Patent Application
20230253375
Exemplary embodiments of the invention relate generally to a displaying apparatus having light emitting devices, a method of manufacturing the same, and a method of transferring light emitting devices.
Light emitting devices are semiconductor devices using light emitting diodes which are inorganic light sources, and are used in various fields such as displaying apparatuses, automobile lamps, general lighting, and the like. Light emitting diodes have advantages such as long lifespan, low power consumption, and rapid response, and thus are rapidly replacing existing light sources.
In the meantime, a conventional light emitting diode has been mainly used as a light source of a backlight unit in a displaying apparatus. Recently, a micro LED used in a displaying apparatus implementing a direct image using a light emitting diode has been developed.
A displaying apparatus generally implements various colors by using mixed colors of blue, green and red. The displaying apparatus comprises a plurality of pixels to implement various images, and each pixel has blue, green, and red subpixels. A color of a particular pixel is determined through colors of these subpixels, and an image is implemented by a combination of these pixels.
In the case of a micro LED display, micro LEDs are arranged on a two-dimensional plane corresponding to each sub-pixel, and thus it is necessary that a large number of micro LEDs are arranged on one substrate. However, the micro LED whose size is less than 200 microns, further less than 100 microns is very small, and various problems occur because of these small sizes. In particular, it is difficult to handle light emitting diodes of a small size and it is not easy to mount a light emitting diode on a display panel.
The above information disclosed in this Background section is only for understanding of the background of the inventive concepts, and, therefore, it may contain information that does not constitute prior art.
Exemplary embodiments of the inventive concepts provide a method of manufacturing a displaying apparatus by which a plurality of light emitting devices formed on a growth substrate can be easily mounted on a display panel substrate and a displaying apparatus manufactured through the method.
Exemplary embodiments of the inventive concepts also provide a method of transferring light emitting devices capable of safely transferring a large amount of light emitting devices to a display panel substrate.
Additional features of the inventive concepts will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts.
A displaying apparatus according to an exemplary embodiment may comprise: a panel substrate; a plurality of light emitting devices arranged on the panel substrate; and at least one connection tip disposed on one surface of each of the light emitting devices, wherein each of the light emitting devices may comprise a light emitting structure comprising a first conductivity type semiconductor layer, a second conductivity type semiconductor layer and an active layer interposed between the first and second conductivity type semiconductor layers; and first and second electrode pads disposed on the light emitting structure.
A method of transferring light emitting device according to an exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a mask layer covering the plurality of light emitting devices, and having at least one hole over each of the light emitting devices; forming a connection layer on the mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a first temporary substrate to an upper surface of the connection layer; removing the substrate and the mask layer from the light emitting devices; coupling a second temporary substrate to lower surfaces of the light emitting devices; and separating the light emitting devices from the connection layer.
A method of transferring light emitting devices according to an exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a first mask layer covering the plurality of light emitting devices; coupling a first temporary substrate to an upper surface of the first mask layer; removing the substrate from the light emitting devices; forming a second mask layer under the first mask layer, and having at least one hole under each of the light emitting devices; forming a connection layer under the second mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a second temporary substrate to a lower surface of the connection layer; removing the first temporary substrate and the first and second mask layers from the light emitting devices; and separating the light emitting devices from the connection layer.
A method of manufacturing a displaying apparatus according to an exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a mask layer covering the plurality of light emitting devices, and having at least one hole over each of the light emitting devices; forming a connection layer on the mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a first temporary substrate to an upper surface of the connection layer; removing the substrate and the mask layer from the light emitting devices; coupling a second temporary substrate to lower surfaces of the light emitting devices; separating the light emitting devices from the connection layer; and separating at least one light emitting device among the plurality of light emitting devices disposed on the second temporary substrate from the second temporary substrate.
A method of manufacturing a displaying apparatus according to an exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a first mask layer covering the plurality of light emitting devices; coupling a first temporary substrate onto the first mask layer; removing the substrate from the light emitting devices; forming a second mask layer under the first mask layer, and having at least one hole under each of the light emitting devices; forming a connection layer on the second mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a second temporary substrate to a lower surface of the connection layer; removing the first temporary substrate and the first and second mask layers from the light emitting devices; and separating at least one light emitting device among the light emitting devices on the second temporary substrate from the connection layer.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention, and together with the description serve to explain the inventive concepts.
In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of various exemplary embodiments or implementations of the invention. As used herein “embodiments” and “implementations” are interchangeable words that are non-limiting examples of devices or methods employing one or more of the inventive concepts disclosed herein. It is apparent, however, that various exemplary embodiments may be practiced without these specific details or with one or more equivalent arrangements. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring various exemplary embodiments. Further, various exemplary embodiments may be different, but do not have to be exclusive. For example, specific shapes, configurations, and characteristics of an exemplary embodiment may be used or implemented in another exemplary embodiment without departing from the inventive concepts.
Unless otherwise specified, the illustrated exemplary embodiments are to be understood as providing exemplary features of varying detail of some ways in which the inventive concepts may be implemented in practice. Therefore, unless otherwise specified, the features, components, modules, layers, films, panels, regions, and/or aspects, etc. (hereinafter individually or collectively referred to as “elements”), of the various embodiments may be otherwise combined, separated, interchanged, and/or rearranged without departing from the inventive concepts.
The use of cross-hatching and/or shading in the accompanying drawings is generally provided to clarify boundaries between adjacent elements. As such, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, dimensions, proportions, commonalities between illustrated elements, and/or any other characteristic, attribute, property, etc., of the elements, unless specified. Further, in the accompanying drawings, the size and relative sizes of elements may be exaggerated for clarity and/or descriptive purposes. When an exemplary embodiment may be implemented differently, a specific process order may be performed differently from the described order. For example, two consecutively described processes may be performed substantially at the same time or performed in an order opposite to the described order. Also, like reference numerals denote like elements.
When an element, such as a layer, is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it may be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. When, however, an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present. To this end, the term “connected” may refer to physical, electrical, and/or fluid connection, with or without intervening elements. Further, the D1-axis, the D2-axis, and the D3-axis are not limited to three axes of a rectangular coordinate system, such as the x, y, and z-axes, and may be interpreted in a broader sense. For example, the D1-axis, the D2-axis, and the D3-axis may be perpendicular to one another, or may represent different directions that are not perpendicular to one another. For the purposes of this disclosure, “at least one of X, Y, and Z” and “at least one selected from the group consisting of X, Y, and Z” may be construed as X only, Y only, Z only, or any combination of two or more of X, Y, and Z, such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms “first,” “second,” etc. may be used herein to describe various types of elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. Thus, a first element discussed below could be termed a second element without departing from the teachings of the disclosure.
Spatially relative terms, such as “beneath,” “below,” “under,” “lower,” “above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), and the like, may be used herein for descriptive purposes, and, thereby, to describe one elements relationship to another element(s) as illustrated in the drawings. Spatially relative terms are intended to encompass different orientations of an apparatus in use, operation, and/or manufacture in addition to the orientation depicted in the drawings. For example, if the apparatus in the drawings is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90 degrees or at other orientations), and, as such, the spatially relative descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms, “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. Moreover, the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It is also noted that, as used herein, the terms “substantially,” “about,” and other similar terms, are used as terms of approximation and not as terms of degree, and, as such, are utilized to account for inherent deviations in measured, calculated, and/or provided values that would be recognized by one of ordinary skill in the art.
Various exemplary embodiments are described herein with reference to sectional and/or exploded illustrations that are schematic illustrations of idealized exemplary embodiments and/or intermediate structures. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, exemplary embodiments disclosed herein should not necessarily be construed as limited to the particular illustrated shapes of regions, but are to include deviations in shapes that result from, for instance, manufacturing. In this manner, regions illustrated in the drawings may be schematic in nature and the shapes of these regions may not reflect actual shapes of regions of a device and, as such, are not necessarily intended to be limiting.
As customary in the field, some exemplary embodiments are described and illustrated in the accompanying drawings in terms of functional blocks, units, and/or modules. Those skilled in the art will appreciate that these blocks, units, and/or modules are physically implemented by electronic (or optical) circuits, such as logic circuits, discrete components, microprocessors, hard-wired circuits, memory elements, wiring connections, and the like, which may be formed using semiconductor-based fabrication techniques or other manufacturing technologies. In the case of the blocks, units, and/or modules being implemented by microprocessors or other similar hardware, they may be programmed and controlled using software (e.g., microcode) to perform various functions discussed herein and may optionally be driven by firmware and/or software. It is also contemplated that each block, unit, and/or module may be implemented by dedicated hardware, or as a combination of dedicated hardware to perform some functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions. Also, each block, unit, and/or module of some exemplary embodiments may be physically separated into two or more interacting and discrete blocks, units, and/or modules without departing from the scope of the inventive concepts. Further, the blocks, units, and/or modules of some exemplary embodiments may be physically combined into more complex blocks, units, and/or modules without departing from the scope of the inventive concepts.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein.
A displaying apparatus according to an exemplary embodiment may comprise: a panel substrate; a plurality of light emitting devices arranged on the panel substrate; and at least one connection tip disposed on one surface of each of the light emitting devices, wherein each of the light emitting devices may comprise a light emitting structure comprising a first conductivity type semiconductor layer, a second conductivity type semiconductor layer and an active layer interposed between the first and second conductivity type semiconductor layers; and first and second electrode pads disposed on the light emitting structure.
In one exemplary embodiment, the at least one connection tip is disposed on the light emitting structure, and may be disposed between the first and second electrode pads.
A thickness of the at least one connection tip may be smaller than thicknesses of the first and second electrode pads. Accordingly, an upper end of the connection tip is located lower than upper ends of the first and second electrode pads.
In one exemplary embodiment, the at least one connection tip may be disposed on an opposite side of the light emitting structure opposite to the first and second electrode pads.
The at least one connection tip may contact the first conductivity type semiconductor layer.
In addition, a plurality of connection tips may be disposed on each of the light emitting devices, and wherein the plurality of connection tips arranged on each of the light emitting devices may be disposed asymmetrically to at least one alignment direction of the light emitting devices arranged on the panel substrate.
Here, the at least one connection tip may comprise three connection tips arranged in triangular shape, wherein one of the three connection tips may be disposed along a first row, and the others may be disposed along another row adjacent to the first row.
The at least one connection tip may further comprise a connection tip disposed at a center of the light emitting device, wherein the connection tip disposed at the center of the light emitting device may be disposed in the triangle formed by the three connection tips.
Furthermore, the connection tips may have right triangular shapes. In addition, the connection tip disposed at the center of the light emitting device may be disposed in a different direction from that of the other connection tips.
The plurality of connection tips may have different thicknesses.
In the meantime, an area ratio of the connection tip to a planar area of the light emitting device may be 1.2% or less.
The first electrode pad may be electrically connected to the first conductivity type semiconductor layer through a via-hole formed in the second conductivity type semiconductor layer and the active layer.
In addition, the light emitting device may further comprise an insulation layer covering the second conductivity type semiconductor layer and side surfaces of the first conductivity type semiconductor layer.
The light emitting device may further comprise an ohmic-layer disposed on the second conductivity type semiconductor layer, and the insulation layer may cover the ohmic-layer and side surfaces of the first conductivity type semiconductor layer.
The displaying apparatus may further comprise: bumps electrically connected to the light emitting devices; a base substrate disposing opposite to the bumps and transmitting light emitted from the light emitting devices; a step adjustment layer disposed between the bumps and the light emitting devices to cover the light emitting devices; and an adhesive layer disposed between the base substrate and the light emitting devices to adhere the light emitting devices to the base substrate, wherein the step adjustment layer and the adhesive layer cover side surfaces of the light emitting device.
In addition, the displaying apparatus may further comprise a protection layer covering side surfaces of the bumps and the step adjustment layer.
Furthermore, the connection tip may be buried in the adhesive layer.
The base substrate may have irregularities on the surface thereof.
The displaying apparatus may further comprise: a light blocking layer disposed between the adhesive layer and the base substrate, wherein the light blocking layer may have a window transmitting light generated in the light emitting device, and a width of the window may be smaller than that of the light emitting device.
A method of transferring light emitting device according to another exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a mask layer covering the plurality of light emitting devices, and having at least one hole over each of the light emitting devices; forming a connection layer on the mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a first temporary substrate to an upper surface of the connection layer; removing the substrate and the mask layer from the light emitting devices; coupling a second temporary substrate to lower surfaces of the light emitting devices; and separating the light emitting devices from the connection layer.
Furthermore, the method of transferring light emitting device may further comprise transferring at least one light emitting device among the plurality of light emitting devices disposed on the second temporary substrate to another substrate.
Here, separating the light emitting devices from the connection layer may be performed by applying an external force to one side of the second temporary substrate in a direction opposite to the first temporary substrate.
As the connection layer and the light emitting devices are separated by the external force, connection tips as portions of the connection layer may remain on the light emitting devices.
In addition, in the step of coupling the first temporary substrate, the first temporary substrate may be coupled to the upper surface of the connection layer so as to dispose a film portion between the connection layer and the first temporary substrate.
The method may further comprise, after the mask layer is removed, removing the first temporary substrate disposed over the light emitting devices from the film portion, wherein the second temporary substrate may be coupled to lower surfaces of the light emitting devices after the first temporary substrate is removed.
A method of transferring light emitting device according to another exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a first mask layer covering the plurality of light emitting devices; coupling a first temporary substrate to an upper surface of the first mask layer; removing the substrate from the light emitting devices; forming a second mask layer under the first mask layer, and having at least one hole under each of the light emitting devices; forming a connection layer under the second mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a second temporary substrate to a lower surface of the connection layer; removing the first temporary substrate and the first and second mask layers from the light emitting devices; and separating the light emitting devices from the connection layer.
When the light emitting devices are separated from the connection layer, a portion of the connection layer may remain on at least one of the light emitting devices to form a connection tip.
A method of manufacturing a displaying apparatus according to another exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a mask layer covering the plurality of light emitting devices, and having at least one hole over each of the light emitting devices; forming a connection layer on the mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a first temporary substrate to an upper surface of the connection layer; removing the substrate and the mask layer from the light emitting devices; coupling a second temporary substrate to lower surfaces of the light emitting devices; separating the light emitting devices from the connection layer; and separating at least one light emitting device among the plurality of light emitting devices disposed on the second temporary substrate from the second temporary substrate.
Separating the light emitting devices from the connection layer may be performed by applying an external force to one side of the second temporary substrate in a direction perpendicular to the first temporary substrate.
A method of manufacturing a displaying apparatus according to another exemplary embodiment may comprise: forming a plurality of light emitting devices regularly arranged on a substrate; forming a first mask layer covering the plurality of light emitting devices; coupling a first temporary substrate onto the first mask layer; removing the substrate from the light emitting devices; forming a second mask layer under the first mask layer, and having at least one hole under each of the light emitting devices; forming a connection layer on the second mask layer, the connection layer being connected to the light emitting devices through the holes; coupling a second temporary substrate to a lower surface of the connection layer; removing the first temporary substrate and the first and second mask layers from the light emitting devices; and separating at least one light emitting device among the light emitting devices on the second temporary substrate from the connection layer.
Here, when the light emitting device is separated from the connection layer, a portion of the connection layer may remain on the light emitting device to form a connection tip.
The present disclosure may be variously modified and realized in many different forms, and thus specific embodiments will be exemplified in the drawings and described in detail hereinafter. However, the present disclosure should not be limited to the specific disclosed forms, and be construed to include all modifications, equivalents, or replacements included in the inventive concepts.
The present disclosure relates a light emitting device including a pixel. The light emitting device in the present disclosure includes a displaying apparatus and/or a lighting device including a light emitting device. In the light emitting device, in a case where light emitting devices are used as pixels that display an image, the light emitting device may be used as the displaying apparatus. The displaying apparatus includes a television set, a tablet computer, an e-book displaying apparatus, a computer monitor, a kiosk, a digital camera, a game console, a mobile phone, a personal digital assistant (PDA), a large-sized outdoor/indoor display board, or the like. The lighting device may include a backlight used for the displaying apparatus, an indoor/outdoor lighting device, a street light device, or a vehicle lighting device.
The light emitting device according to an exemplary embodiment includes micro-light emitting devices. The micro-light emitting devices may be elements with a width or length of about 1 micrometer to about 800 micrometers scale, about 1 micrometer to about 500 micrometers scale, or about 10 micrometers to about 300 micrometers scale. However, the micro-light emitting devices do not need to have the width or length in the above-mentioned ranges and, if necessary, may have a smaller or larger width or length.
Hereinafter, exemplary embodiments will be explained in detail with reference to the accompanying drawings.
Referring to
The substrate 10 includes at least one pixel area 10d and a non-pixel area 10nd surrounding the pixel area 10d. The pixel area 10d corresponds to an area in which the pixel 111 is disposed and through which a light exiting from a light emitting device 150 described later travels to be perceived by a user. The non-pixel area 10nd corresponds to an area except for the pixel area 10d. The non-pixel area 10nd is provided adjacent to at least one side portion of the pixel 111, and in the exemplary embodiment, the non-pixel area 10nd is provided to surround the pixel area 10d.
The substrate 10 may be formed of a light transmitting insulating material. The expression of “the substrate 10 has the light transmitting property” indicates various cases where the substrate 10 is transparent to transmit the light entirely, the substrate 10 is semi-transparent to transmit only light having a specific wavelength, and the substrate 10 is partially transparent to transmit only a portion of the light having the specific wavelength.
As the material for the substrate 10, a glass, a quartz, an organic polymer, or an organic-inorganic composite material may be used, however it should not be limited thereto or thereby. That is, the material for the substrate 10 should not be particularly limited as long as the material is optically transparent and insulative.
Each pixel unit 110 is a minimum unit that displays the image and the pixel unit is provided in plural in the display. Each pixel unit 110 may emit a white light and/or a color light. Each pixel unit 110 may include one pixel 111 emitting one color or may include plural pixels 111 different from each other to emit the white light and/or the color light obtained by combining different colors. For example, each pixel unit 110 may include first, second, and third pixels 111a, 111b, and 111c.
The pixel 111 is provided in the pixel area 10d of the substrate 10. The pixel 111 is provided in one pixel area 10d in a group or one-to-one fashion according to embodiments. In other words, each pixel unit 110 may be provided with at least one pixel 111, for example, each pixel unit 110 may include the first, second, and third pixels 111a, 111b, and 111c. The first, second, and third pixels 111a, 111b, and 111c are provided in first, second, and third pixel areas 10a, 10b, and 10c, respectively. The first, second, and third pixels 111a, 111b, and 111c may be implemented by first, second, and third light emitting devices 150a, 150b, and 150c that emit lights having different wavelength bands from each other. That is, when the lights emitted by the first, second, and third light emitting devices 150a, 150b, and 150c are referred to as “first, second, and third lights”, respectively, the first to third lights may have different wavelength bands. In the exemplary embodiment, the first, second, and third lights may correspond to blue, red, and green wavelength bands, respectively. However, the wavelength bands of the lights emitted by the pixels 111 included in each pixel unit 110 should not be limited thereto or thereby, and the wavelength bands may correspond to cyan, magenta, and yellow wavelength bands. Hereinafter, a structure in which each pixel unit 110 includes the first, second, and third pixels 111a, 111b, and 111c that respectively emit blue, red, and green lights will be described as an example.
The pixel 111 includes a light passing layer 120 provided on the substrate 10, the light emitting device 150 provided on the light passing layer 120, an insulation layer 160 provided on the light emitting device 150, and a terminal part 170 provided on the insulation layer 160.
The light passing layer 120 is a layer through which a light emitted from the light emitting device 150 passes and is provided in the pixel area 10d. The light passing layer 120 may be provided in each pixel area 10d in a one-to-one fashion. For example, when the first, second, and third pixels 111a, 111b, and 111c are provided, the light passing layer 120 is provided in every first, second, and third pixels areas 10a, 10b, and 10c in which the first, second, and third pixels 111a, 111b, and 111c are respectively provided. In
When viewed in a plan view, the light passing layer 120 is provided in a shape corresponding to a shape of the pixel area 10d. when viewed in a cross section, the light passing layer 120 has a rectangular shape with an upper surface 120p and a side surface 120q. In the exemplary embodiment, the upper surface 120p may be substantially parallel to a surface of the substrate 10 disposed thereunder such that the light emitting device 150 may be provided on the upper surface 120p.
The light reaching the light passing layer 120 from the light emitting device 150 passes through the light passing layer 120 after being incident into the light passing layer 120 and exits to the outside. The light passing layer 120 transmits at least a portion (e.g., at least a portion of light amount and/or at least a portion of specific wavelength) of the light from the light emitting device 150.
The light passing through the light passing layer 120 may maintain a wavelength thereof when being incident into the light passing layer 120 or may be converted to a light with a wavelength different from the wavelength when being incident into the light passing layer 120.
In the case where the light passing through the light passing layer 120 maintains the same wavelength before and after passing through the light passing layer 120, the light passing layer 120 may serve as a waveguide. In the case where the light passing through the light passing layer 120 have different wavelengths before and after passing through the light passing layer 120, the light passing layer 120 may serve as a light conversion layer 120f. In the present exemplary embodiment, for the convenience of explanation, when the light passing layer 120 serves as the light conversion layer 120f, the light passing layer 120 will be referred to as the “light conversion layer” 120f and will be assigned with a separate reference numeral. However, it should be understood that the light conversion layer 120f has been explained as a component included in the light passing layer 120 depending on situations.
As described above, the light conversion layer 120f absorbs the wavelength of the light from the light emitting device 150 and emits the light having the different wavelength. The light conversion layer 120f absorbs the light of relatively shorter wavelength and emits the light having longer wavelength than that of the absorbed light. The light conversion layer 120f may selectively include materials that are able to absorb a light having a predetermined wavelength and emit a light having a different wavelength. As an example, the light conversion layer 120f may include a nano-structure such as a fluorescent substance and a quantum dot, an organic material capable of converting color, or a combination thereof. For example, when the fluorescent substance is used as the material for the light conversion layer 120f, the fluorescent substance may absorb a blue light and may emit a red light. The fluorescent substance may be provided in a mixed form with a transparent or semi-transparent binder, such as PDMS (polydimethylsiloxane), PI (polyimide), PMMA (poly(methyl 2-methylpropenoate)), or ceramic.
The light emitting device 150 is provided on the light conversion layer 120f such that an adhesive layer 180 is disposed between the light emitting device 150 and the light conversion layer 120f. The adhesive layer 180 may include a non-conductive material and may include a material with the light transmitting property. For instance, the adhesive layer 180 may be an optically clear adhesive (OCA). The material for the adhesive layer 180 should not be particularly limited as long as the material is optically clear and stably attaches the light emitting device 150. The adhesive layer 180 is provided in the pixel area 10d corresponding to an area to which the light emitting device 150 is attached and has an area corresponding to an area of the light emitting device 150 when viewed in a plan view.
The light emitting device 150, for example, the first, second, and third light emitting devices 150a, 150b, and 150c are provided on the light passing layers, respectively, with the adhesive layer 180 therebetween.
The light emitting device 150 may be provided in each pixel 111 to emit the lights of various wavelengths.
In the exemplary embodiment, the first, second, and third lights may have blue, red, and green wavelength bands. In this case, the first, second, and third light emitting devices 150a, 150b, and 150c may be implemented by a blue light emitting diode, a red light emitting diode, and a green light emitting diode. However, the first, second, and third lights need not have the blue, red, and green wavelength bands, respectively, to display the blue, red, and green colors. Although the first to third lights have the same wavelength band, the color of the light finally emitted may be controlled by using the light conversion layer 120f that converts at least a portion of the first to third lights to a light having a different wavelength band. This is because the light conversion layer 120f includes the material, such as the fluorescent substance or the quantum dot, that converts the light having the predetermined wavelength to the light having the different wavelength. In other words, the first, second, and third pixels 111a, 111b, and 111c do not necessarily use the green, red, and blue light emitting diodes to implement the green, red, and/or blue colors, and light emitting diodes other than the above-mentioned color may be used. As an example, the red light emitting diode may be used to implement the red color, however, when using the light conversion layer 120f that absorbs the blue light or the ultraviolet light and emit the red light, the blue or ultraviolet light emitting diode may used to implement the red color.
The light conversion layer 120f may selectively include materials that are able to absorb a light having a predetermined wavelength and emit a light having a different wavelength. The light conversion layer 120f may include the nano-structure such as the fluorescent substance and the quantum dot, an organic material capable of converting colors, or the combination thereof. A color filter layer 130 may be further disposed at a portion adjacent to the light conversion layer 120f to increase a purity of the color of the light finally emitted.
In the exemplary embodiment, it will be described that the first light emitting device 150a is green light emitting diode, the second light emitting device is a blue light emitting diode and the third light emitting device 150c is a blue light emitting diode, as an example
In the exemplary embodiment, the first, second, and third light emitting devices 150a, 150b, and 150c are shown to have the same size, however, the first, second, and third light emitting devices 150a, 150b, and 150c may have the same size or different sizes from each other.
As shown in drawings, the first, second, and third light emitting devices 150a, 150b, and 150c are shown to have the same height, however the first, second, and third light emitting devices 150a, 150b, and 150c may have the same height as or different heights from each other. According to embodiments, at least one light emitting device of the first, second, and third light emitting devices 150a, 150b, and 150c may have a different height from those of the other light emitting devices. The height of the first, second, and third light emitting devices 150a, 150b, and 150c may vary depending on the materials and optical characteristics of the first, second, and third light emitting devices 150a, 150b, and 150c. For example, the first light emitting device 150a emitting the green light may have the height greater than that of the third light emitting device 150c emitting the blue light. However, in the exemplary embodiment, although the first, second, and third light emitting devices 150a, 150b, and 150c have different heights from each other, the heights of the first, second, and third light emitting devices 150a, 150b, and 150c are lower than those of a conventional light emitting device since the first, second, and third light emitting devices 150a, 150b, and 150c are manufactured by a manufacturing method described later and transferred onto the substrate by a transferring method described later. That is, first to third light emitting devices used in the conventional light emitting apparatus are transferred onto a substrate with a growth substrate when being employed in the conventional light emitting apparatus. However, since the first to third light emitting devices used in the light emitting apparatus according to the exemplary embodiment are transferred right after being separated from the growth substrate, the heights of the light emitting devices are lower than those of the conventional light emitting device. For instance, in the exemplary embodiment, the height from an upper surface of the substrate to an active layer may be in a range from about 2 micrometers to about 15 micrometers. As another way, in the exemplary embodiment, the height from the upper surface of the substrate to the active layer may be in a range from about 5 micrometers to about 10 micrometers.
In the exemplary embodiment, the first, second, and third light emitting devices 150a, 150b, and 150c are provided separated from an element substrate (e.g., a sapphire substrate) for growth of a semiconductor layer. Accordingly, it is possible to thin the device. In particular, in a case of the light emitting devices emitting the green and blue lights, for example, since the first and third light emitting devices may be provided without the sapphire substrate, a thickness of the light emitting device may be equal to or smaller than about 15 micrometers. When the sapphire substrate is provided, the thickness of the light emitting device has a remarkably larger value (e.g., about 50 micrometers to about 100 micrometers) than that when the sapphire substrate is not provided. Therefore, in the exemplary embodiment, a difference in thickness between the light emitting devices depending on the presence or absence of the element substrate may be reduced, and defects caused by a difference in height may be prevented in the following other processes described later.
The insulation layer 160 is provided on the light emitting device 150. The insulation layer 160 is provided in all the pixel area 10d and the non-pixel area 10nd. The insulation layer 160 covers an upper surface of the light passing layer 120 and the light emitting device 150 in an area corresponding to the pixel area 10d. A space between the pixel area 10d and another pixel area 10d is filled with the insulation layer 160 in an area corresponding to the non-pixel area 10nd, and the insulation layer 160 makes contact with the upper surface of the substrate 10. The insulation layer 160 is provided between the light passing layers 120 respectively provided in the pixel areas 10d. Accordingly, the light passing layers 120 are separated by the insulation layer 160. Therefore, all the upper surface and the side surface of the light passing layer 120 are covered by the insulation layer 160.
The insulation layer 160 includes a non-conductive material. The insulation layer 160 may include a material that transmits the light or a material that does not transmit the light. According to embodiments, when a color mixture occurs between the pixels 111 adjacent to each other, the insulation layer 160 may include a non-transmitting material, and when the color mixture is required or there is no possibility of color mixture, the insulation layer 160 may include a transmitting material.
As the transmitting material, an organic polymer, such as epoxy, polysiloxane, or photoresist, may be used. As an example, PDMS (polydimethylsiloxane) may be used as the polysiloxane material. However, the material for the insulation layer 160 should not be limited thereto or thereby, and materials, such as HSSQ (Hydrogen Silsesquioxane), MSSQ (Methyksilsesquioxane), polyimide, Divinyl Siloxane, DVS-BCS (bis-Benzocyclobutane), PFCB (Perfluorocyclobutane), and PAE (Polyarylene Ether) may be used.
The non-transmitting material may include a light absorbing material and may include a material substantially having a light transmittance equal to or smaller than about 10%. For example, the insulation layer 160 may have a black color, and particularly may include a black matrix material used in a displaying apparatus. In the present exemplary embodiment, the insulation layer 160 may include a black photoresist and may include a carbon black. In the case where the insulation layer 160 includes the black photoresist, the insulation layer 160 may be easily patterned using a photolithography process. However, the material for the insulation layer 160 should not be limited thereto or thereby, and various materials may be used for the insulation layer 160.
The insulation layer 160 may have a single-layer structure or a multi-layer structure. In the exemplary embodiment, the insulation layer 160 may include a first insulation layer 161 provided on the substrate 10 and a second insulation layer 163 provided on the first insulation layer 161. The first insulation layer 161 may be provided on the substrate 10 and disposed in the non-pixel area 10nd between the light passing layers 120. The second insulation layer 163 may be provided on the light passing layer 120 and the light emitting device 150 and may be provided in all the pixel area 10d and the non-pixel area 10nd. In the present exemplary embodiment, the first insulation layer 161 and the second insulation layer 163 may include the same material as or different materials from each other.
A plurality contact holes is defined by partially removing the insulation layer 160 to expose at least a portion of first and second electrodes 159p and 159q of the light emitting device 150.
The terminal part 170 is provided on the insulation layer 160 and connected to the light emitting device 150.
The terminal part 170 may include a common pad 171d used to apply a common voltage to the light emitting device 150 and a data pad used to apply image signals, i.e., data signals, to the light emitting device 150. The data pad includes first, second, and third data pads 171a, 171b, and 171c that respectively apply the data signals to the first, second, and third light emitting devices 150a, 150b, and 150c.
The terminal part 170 is electrically connected to each light emitting device 150 through the contact hole CH defined through the insulation layer 160. That is, the common pad 171d and the first data pad 171a are connected to the first light emitting device 150a through the contact hole CH. The common pad 171d and the second data pad 171b are connected to the second light emitting device 150b through the contact hole CH. The common pad 171d and the third data pad 171c are connected to the third light emitting device 150c through the contact hole CH.
Various types of light emitting diodes may be employed as the first, second, and third light emitting devices 150a, 150b, and 150c.
Referring to
In an embodiment, in a case of the light emitting device 150 that emits the green light, the first semiconductor layer 153, the active layer 155, and the second semiconductor 157 may include indium gallium nitride (InGaN), gallium nitride (GaN), aluminum indium gallium nitride (AlInGaN), gallium phosphide (GaP), aluminum gallium indium phosphide (AlGaInP), and aluminum gallium phosphide (AlGaP). In an embodiment, in a case of the light emitting device 150 that emits the red light, the first semiconductor layer 153, the active layer 155, and the second semiconductor 157 may include aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), and gallium phosphide (GaP). In an embodiment, in a case of the light emitting device 150 that emits the blue light, the first semiconductor layer 153, the active layer 155, and the second semiconductor 157 may include gallium nitride (GaN), indium gallium nitride (InGaN), aluminum indium gallium nitride (AlInGaN), and zinc selenide (ZnSe).
In the present exemplary embodiment, the first and second semiconductor layers may be doped with impurities of opposite types and may be an n-type or p-type semiconductor layer depending on the type of impurity. For example, the first semiconductor layer may be the n-type semiconductor layer, and the second semiconductor layer may be the p-type semiconductor layer. On the contrary, the first semiconductor layer may be the p-type semiconductor layer, and the second semiconductor layer may be the n-type semiconductor layer. In the following descriptions, a configuration in which the first semiconductor layer is the n-type semiconductor layer and the second semiconductor layer is the p-type semiconductor layer will be described as a representative example.
In
The first electrode 159p is disposed on the first semiconductor layer 153 on which the active layer 155 and the second semiconductor layer 157 are not provided, and the second electrode 159q is disposed on the second semiconductor layer 157.
The first electrode 159p and/or the second electrode 159q may have a single- or multi-layer structure of metal. The first electrode 159p and/or the second electrode 159q may include various metals of Al, Ti, Cr, Ni, Au, Ag, Cr, or Cu and an alloy thereof.
In the present exemplary embodiment, a plurality of concavo-convex portions may be provided on a rear surface (i.e., an opposite surface of the surface on which the active layer 155 is provided) of the first semiconductor layer 153 to increase a light emitting efficiency. The concavo-convex portions may be provided in various shapes, such as a polygonal pyramid, a hemisphere, or a surface having a roughness, on which the concavo-convex portions are randomly arranged. As an example, the rear surface of the first semiconductor layer 153 may be textured through various etching processes. As another way, various shapes of concavo-convex portions may be formed on the first semiconductor layer 153 by forming the first semiconductor layer 153 on the patterned sapphire substrate and separating the sapphire substrate.
The insulation layer 160 is provided on the first and second electrodes 159p and 159q, and the common pad 171d connected to the first electrode 159p through the contact hole CH and the data pad 171a are provided on the insulation layer 160. In the present exemplary embodiment, the first electrode 159p is connected to the common pad 171d, and the second electrode 159q is connected to the data pad 171a, however this is for the convenience of explanation, and they should not be limited thereto or thereby. For example, the first data pad 171a may be connected to the first electrode 159p, and the common pad 171d may be connected to the second electrode 159q.
The common pad 171d and/or the first data pad 171a may include a single- or multi-layer of metal. The common pad 171d and/or the first data pad 171a may include various metals of Al, Ti, Cr, Ni, or Au and an alloy thereof.
In the exemplary embodiment, the light emitting device 150 is roughly described with reference to drawings. The light emitting device 150 may further include a layer with additional functionality in addition to the above-mentioned layers. For instance, various layers, such as a reflection layer that reflects the light, an additional insulation layer that insulates specific components, and a solder prevention layer that prevents a solder from being diffused, may be included in the light emitting device 150.
In addition, when the lateral-type light emitting device is formed, a mesa may be formed in various shapes, and locations and shapes of the first and second electrodes may be changed in various ways.
According to the light emitting apparatus of the exemplary embodiment, the light emitting device 150 is turned on in response to the common voltage and the data signal applied thereto to emit the light, and the emitted light travels to the rear surface of the substrate 10 after passing through the substrate 10 thereunder.
According to the light emitting apparatus of the exemplary embodiment, since the pixels and the terminal part are sequentially formed on the substrate, the light emitting apparatus may be manufactured without using a separate printed circuit board. In a case where the light emitting apparatus is manufactured by mounting the light emitting device on the separate printed circuit board, a process for forming a conductive electrode on the printed circuit board and/or a process for connecting a wire are required. However, the forming and connecting processes may be omitted in the exemplary embodiment. The manufacturing method of the displaying apparatus will be described later.
According to the light emitting apparatus of the above-described embodiment, the manufacturing process is simplified, and color purity and color reproducibility are also improved.
In a conventional displaying apparatus, when a pixel is formed by mounting a light emitting apparatus on a substrate, the light emitting apparatus is mounted on a transparent insulation layer formed on the substrate. In a case where the insulation layer used on the substrate is transparent, the transparent insulation layer is used as a waveguide, and thus there is a problem in which a light is propagated from one pixel to another pixel adjacent to the one pixel. However, according to the exemplary embodiment, since the insulation layer that does not transmit the light is provided in each pixel area 10d, the insulation layer is not used as the waveguide. In particular, the insulation layer may be provided to have the black color, and thus the light may be prevented from traveling to adjacent pixels. Accordingly, the color mixture or a light interference between the pixels adjacent to each other may be prevented, and the final color purity and color reproducibility may be improved
In addition, since the area displayed in the black color increases, a contrast ratio between the black area and the light emitted from each light emitting apparatus increases, and characteristics of the displaying apparatus is improved.
Further, according to the exemplary embodiment, a color filter layer or a color filter part may be additionally used in addition to the light conversion layer. Therefore, the color purity and the color reproducibility may be further improved. The light that is not completely converted by the light conversion layer or the light traveling from the adjacent pixel are blocked once again by the color filter layer or the color filter part.
According to the exemplary embodiment, the light emitting apparatus may have various configurations without departing from the inventive concepts.
Referring to
The first sub-insulation layer 161p may be provided on a substrate 10 to directly make contact with the substrate 10, and a side surface and an upper surface of the first sub-insulation layer 161p may be completely covered by the second sub-insulation layer 161q. As another way, the first sub-insulation layer 161p may be provided at the same height as a light passing layer 120, and in this case, the upper surface of the first sub-insulation layer 161p may be covered by a second insulation layer 163.
The first sub-insulation layer 161p may be provided as a white insulation layer 160. The second sub-insulation layer 161q may be provided as a black insulation layer 160. When the white insulation layer 160 and the black insulation layer 160 are combined with each other, most of the wavelength bands, particularly, most of the light in the visible light band, which is emitted from one pixel, may be prevented from traveling to other pixels 111 adjacent to each other.
In the present exemplary embodiment, the first sub-insulation layer 161p may include an insulating material having the white color, such as an organic polymer or an organic-inorganic composite material. The second sub-insulation layer 161q may include a non-light transmitting material as the second insulation layer 163 and may include the same material as the second insulation layer 163.
The light emitting apparatus according to the exemplary embodiment may further include various additional components to improve the light emitting efficiency.
Referring to
In the exemplary embodiment, the diffusion plate 191 is described as a representative example, however various optical sheets for improving the light efficiency may be further disposed on the rear surface of the substrate 10. For example, a prism sheet for linearity of light and/or a filter for blocking or transmitting a light having a specific wavelength may be further disposed on the rear surface of the substrate 10. The optical sheets may be arranged in various orders depending on desired functions.
The light emitting apparatus according to the exemplary embodiment may further include additional components to improve the light emitting efficiency and prevent the color mixture of the light between pixels adjacent to each other.
Referring to
The reflection layer 140 may include a conductive or non-conductive material that reflects the light emitted from the light emitting device 150. As the conductive material, a metal or metal alloy may be used, and as the non-conductive material, an organic-inorganic composite material or a dielectric mirror may be used.
The metal or metal alloy may include a metal material with high reflectance, e.g., silver, aluminum, copper, platinum, and gold.
The organic-inorganic composite material may be provided in the form of an inorganic filler having a small particle diameter mixed with a polymer resin. The inorganic filler may include barium sulfate, calcium sulfate, magnesium sulfate, barium carbonate, calcium carbonate, magnesium chloride, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, titanium dioxide, alumina, silica, talc, or zeolite, however it should not be limited thereto or thereby.
The dielectric mirror may have a structure in which insulation layers having different refractive indices from each other are stacked one on another. A material for the dielectric mirror should not be particularly limited, and various organic or inorganic materials may be used as the dielectric mirror.
In the exemplary embodiment, the material and structure of the reflection layer 140 may be determined in accordance with the wavelength band of the light emitted from the light emitting device 150 of the corresponding pixel 111. Since specific materials or metals have different reflectances depending on the wavelength, it is advantageous to select the material of the reflection layer 140 among materials with high reflectance in the wavelength band of the light from the light emitting device 150. As an example, in a case where the light emitting device 150 emits a light having an ultraviolet wavelength band, aluminum or an aluminum alloy having high reflectance in the ultraviolet wavelength band may be selected as the material for the reflection layer 140, and the reflectance of the dielectric mirror in the ultraviolet wavelength band may increase by adjusting the material or the number of stacked layers.
In the present exemplary embodiment, the reflection layer 140 provided between the first insulation layer 161 and the side surface 120q of the light passing layer 120 is described, however it should not be limited thereto or thereby. According to another embodiment, the reflection layer 140 may be also provided on the upper surface 120p of the light passing layer 120, i.e., between the light passing layer 120 and the second insulation layer 163. However, in a case where the reflection layer 140 includes the conductive material such as the metal material, the reflection layer 140 is provided in an insulated state not to be electrically connected to a terminal part 170 of the light emitting device 150.
According to the exemplary embodiment, the light emitted from the light emitting device 150 travels through the corresponding light passing layer 120 by the reflection layer 140 and the traveling of the light to the adjacent pixels 111 is prevented as much as possible. As a result, the color mixture in which the light from the specific pixel 111 is mixed with the light from the adjacent pixels 111 may be prevented.
The light emitting apparatus according to the exemplary embodiment may implement the color light using various light emitting devices having different wavelength from the above-mentioned embodiment and the light conversion layer corresponding to the light emitting devices.
Referring to
In the present exemplary embodiment, first, second, and third light emitting devices 150a, 150b, and 150c respectively provided in first, second, and third pixels 111a, 111b, and 111c may emit the ultraviolet light, and the light conversion layer 120f is provided in all the first pixel 111a to the third pixel 111c. Accordingly, the light conversion layer 120f of the first pixel 111a may include a light conversion material that converts the ultraviolet light emitted from the first light emitting device 150a to a blue light, the light conversion layer 120f of the second pixel 111b may include a light conversion material that converts the ultraviolet light emitted from the second light emitting device 150b to a red light, and the light conversion layer 120f of the third pixel 111c may include a light conversion material that converts the ultraviolet light emitted from the third light emitting device 150c to a green light.
The light conversion material may include a nano-structure such as a fluorescent substance and a quantum dot, an organic material capable of converting colors, or a combination thereof and may be selected depending on desired colors.
In the present exemplary embodiment, a color filter part CF may be further provided between a substrate 10 and the light passing layer 120. The color filter part CF may include color filters B, R, and G provided in a pixel area 10d corresponding to each pixel 111 and a black matrix BM provided corresponding to a non-pixel area 10nd. The color filters B, R, and G may be provided corresponding to the color of each pixel 111 and may include a blue color filter B, a red color filter R, and a green color filter G.
The color filters B, R, and G may improve the color purity of the light converted by each light conversion layer 120f and may substantially simultaneously block the light that is not converted among the lights emitted from the light emitting device 150. In particular, in the case where the light emitting device 150 emits the ultraviolet light, a portion of the ultraviolet light may not be converted to the specific color, such as blue, red, and green colors, and the color filter may block the ultraviolet light that is not converted.
The light emitting apparatus according to an exemplary embodiment may implement the color light using various light emitting devices having different wavelength from that in the exemplary embodiment of
Referring to
In the present exemplary embodiment, first, second, and third light emitting devices 150a, 150b, and 150c respectively provided in first, second, and third pixels 111a, 111b, and 111c may emit the blue light. Accordingly, the first pixel 111a corresponding to the blue pixel 111 does not need the light conversion, and the light passing layer 120 that transmits all the lights emitted from the light emitting device 150 is provided. Since the second pixel 111b and the third pixel 111c need the light conversion, the light conversion layer 120f is provided in the second pixel 111b and the third pixel 111c. That is, the light conversion layer 120f of the second pixel 111b may include a light conversion material that converts the blue light emitted from the second light emitting device 150b to the red light, and the light conversion layer 120f of the third pixel 111c may include a light conversion material that converts the blue light emitted from the third light emitting device 150c to the green light.
The light conversion material may include a nano-structure such as a fluorescent substance and a quantum dot, an organic material capable of converting colors, or a combination thereof and may be selected depending on desired colors.
In the present exemplary embodiment, a color filter part CF may be further provided between a substrate 10 and the light passing layer 120. However, since the blue light is emitted from the light emitting device 150 in the case of the first pixel 111a, a blue color filter that additionally blocks ultraviolet light is not required. Accordingly, the blue color filter may be omitted with respect to the first pixel 111a, and a transparent insulation layer T may be provided in the first pixel 111a. On the other hand, since there may be the blue light that is not completely converted by the light conversion layer 120f in the second and third pixels 111b and 111c, a red color filter R and a green color filter G may be respectively provided in the pixel areas 10d to block the blue light that is not completely converted.
In the above-described embodiments, the configuration in which at least one light passing layer among the light passing layers is the light conversion layer is described, however according to the exemplary embodiment, the light emitting apparatus may be manufactured without employing the light conversion layer.
Referring to
For example, in an embodiment, the first light emitting device 150a may include gallium nitride (GaN), indium gallium nitride (InGaN), aluminum indium gallium nitride (AlInGaN), and zinc selenide (ZnSe), and particularly may include aluminum indium gallium nitride (AlInGaN).
In an embodiment, the second light emitting device 150b may include aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide (AlGaInP), and gallium phosphide (GaP), and particularly may include aluminum gallium indium phosphide (AlGaInP).
In an embodiment, the third light emitting device 150c may include indium gallium nitride (InGaN), gallium nitride (GaN), aluminum indium gallium nitride (AlInGaN), and zinc selenide (ZnSe), and particularly may include aluminum indium gallium nitride (AlInGaN).
In the present exemplary embodiment, since each of the first, second, and third light emitting devices 150a, 150b, and 150c emits the color light having the specific wavelength, no separate light conversion layer is required, and the light emitting apparatus may be manufactured in a relatively simple manner.
Referring to
In the present exemplary embodiment, first and second electrodes of the second light emitting device 150b may be respectively provided on upper and lower side surfaces, and each of the first and second electrodes may be electrically connected to a common pad 171d or a second data pad 171b through a contact hole. In the exemplary embodiment, the vertical-type light emitting device has an advantage of occupying less area than the lateral-type light emitting device when viewed in a plan view, and thus the vertical-type light emitting devices can be formed in a higher density than the lateral-type light emitting devices.
As described above, according to the exemplary embodiment, when the light emitting device that emits the light having the specific color is manufactured, it is possible to select the type of the light emitting device that is relatively easy to manufacture among the vertical-type or the lateral-type in accordance with the substrate or material used.
It has been previously described that the lateral or vertical type devices are used, but a light emitting device is not limited to these type devices.
The light emitting apparatus according to the exemplary embodiment may be employed in various apparatuses and, for example, may be employed in a backlight unit used in the displaying apparatus.
Referring to the above-described embodiments and
In the present exemplary embodiment, the terminal part 170 includes the common pad 171p used to apply the common voltage to one electrode of the first and second electrodes of the light emitting device 150 and the data pad 171q used to apply the light emitting signal to the other electrode of the first and second electrodes. The common pad 171p and the data pad 171q may be spaced apart from each other and may extend in one direction. One electrode of the first and second electrodes of each light emitting device 150 may be connected to the common pad 171p through the contact hole CH, and the other electrode of the first and second electrodes of each light emitting device 150 may be connected to the data pad 171q through the contact hole CH. Consequently, each light emitting device 150 is connected in parallel between the common pad 171p and the data pad 171q.
The light emitting apparatus having the above-mentioned structure according to the exemplary embodiments may be manufactured by preparing the substrate and sequentially forming components on the substrate. In particular, the light emitting apparatus may be manufactured through preparing light emitting devices and transferring the light emitting devices to a substrate.
Hereinafter, a method of forming and transferring light emitting devices is first described in sequence, and then a light emitting apparatus will be described.
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In the exemplary embodiment, the second temporary substrate 10q may be a sapphire substrate, and the separation layer 10q′ may include a metal oxide material, such as indium tin oxide (ITO). However, the second temporary substrate 10q and the separation layer 10q′ should not be limited thereto or thereby. That is, the second temporary substrate 10q and the separation layer 10q′ may include various materials as long as they sufficiently support the protective layer 165 and the light emitting devices 150 in the protective layer 165 and are easily removed.
In the present exemplary embodiment, the laser LSR is irradiated to the interface between the light emitting devices 150 and the first temporary substrate 10p while the light emitting devices 150 and the protective layer 165 are supported by the second temporary substrate 10q. In detail, the laser LSR is irradiated to the interface between the first semiconductor layer 153 and the first temporary substrate 10p.
The laser LSR is used to pyrolyze molecules in the interface between the first semiconductor layer 153 and the first temporary substrate 10p. In the exemplary embodiment, the first semiconductor layer 153 includes gallium nitride (GaN), the gallium nitride (GaN) is pyrolyzed by the irradiation of the laser LSR, and as a result, nitrogen atoms are removed as nitrogen gas (N2). Accordingly, an auxiliary layer 151 containing gallium (Ga) is formed between the first semiconductor layer 153 and the first temporary substrate 10p after removing nitride (N) from the gallium nitride (GaN). In this case, since the gallium (Ga) still remains between the first semiconductor layer 153 and the first temporary substrate 10p, the light emitting device is continuously attached onto the substrate due to an adhesion of the gallium (Ga). However, the adhesion between the first semiconductor layer 153 and the first temporary substrate 10p after irradiating the laser LSR is markedly weakened when compared with the adhesion between the first semiconductor layer 153 and the first temporary substrate 10p before irradiating the laser LSR.
The second temporary substrate 10q prevents the light emitting device 150 and the protective layer 165 from being lifted when the laser LSR is irradiated to the interface between the first semiconductor layer 153 and the first temporary substrate 10p. The light emitting device 150 and/or the protective layer 165 adjacent to the light emitting device 150 may be lifted due to heat and gas generated when the laser LSR is irradiated, however, since the second temporary substrate 10q supports the light emitting devices 150 and the protective layer 165 while downwardly pressing the light emitting devices 150 and the protective layer 165, the lift of the light emitting devices 150 and the protective layer 165 may be minimized.
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In the exemplary embodiment, the light emitting devices 150 attached to the conveying apparatus 190 are aligned on and attached to the substrate 10 on which the adhesive layer 180 is formed. In this case, an attachment area between the light emitting device 150 and the adhesive layer 180 may be wider than an attachment area between the light emitting devices 150 and the temporary adhesive layer 181 on the conveying apparatus 190.
Referring to
As described above, according to the exemplary embodiment, the light emitting device formed on the separate substrate may be easily transferred on the desired substrate. In more detail, according to the exemplary embodiment, it is possible to form the epitaxial stack on the growth substrate, such as the sapphire substrate, and to directly transfer the light emitting device from the growth substrate onto the substrate, on which the light emitting device is to be formed. In addition, since it is possible to precisely and selectively align only the light emitting devices corresponding to desired locations on the substrate using the conveying apparatus after forming the light emitting devices on the growth substrate, such as the sapphire substrate, defects caused by misalignment of the light emitting devices in the manufacturing process of the light emitting apparatus are reduced. Further, since it is possible to directly transfer the light emitting device without additional processes, a polishing or breaking process is not needed. Therefore, the manufacturing process of the light emitting apparatus may be simplified, a production yield of the light emitting apparatus may increase, and a manufacturing cost of the light emitting device may be reduced.
In addition, although not shown in drawings, the light emitting device that does not use the gallium nitride (GaN) semiconductor, e.g., the red light emitting device, may be transferred onto the substrate after being manufactured in various ways other than the above-described method. In the exemplary embodiment, the method of manufacturing and transferring the red light emitting device on the gallium arsenide (GaAs) semiconductor substrate may be performed by forming a sacrificial layer on the gallium arsenide (GaAs) semiconductor substrate, forming aluminum gallium indium phosphide (AlGaInP) semiconductor layer on the sacrificial layer, forming the electrode part on the semiconductor layer to manufacture the red light emitting device, removing the sacrificial layer, and conveying the red light emitting device onto the substrate using the conveying apparatus.
In the exemplary embodiment, the light emitting device may be manufactured and transferred as described in
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The patterned first temporary substrate 10p has the concavo-convex portions PR, and each concavo-convex portion PR may be provided in various shapes, such as a polygonal pyramid, a hemisphere, or a surface having a roughness, on which the concavo-convex portions are randomly arranged. In
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As described above, when the concavo-convex portions are formed in the light emitting device, the light emitting efficiency increases. There may be a difference in intensity between lights emitted from the light emitting devices, and the difference in intensity may cause a difference in visibility. Accordingly, the concavo-convex portions may be selectively formed in the light emitting device in accordance with the light emitting efficiency.
In the exemplary embodiments, the light emitting apparatuses according to the above-described embodiments may be manufactured through substantially the same method with some structural differences. Hereinafter, a method of manufacturing the light emitting apparatus shown in
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In the drawings according to the present exemplary embodiment, a process of forming the reflection layer is not shown, however the reflection layer may be further formed on the substrate 10, on which the first insulation layer 161 is formed, before the color filter layer 130 is formed. The reflection layer may be formed, for example, by forming the metal layer or the dielectric mirror layer and patterning the metal layer or the dielectric mirror layer using a photolithography process.
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The light emitting apparatus according to the exemplary embodiment may be easily formed using the above-described method. In particular, since the pixels and the terminal part may be sequentially formed on the substrate using the conventional processes, e.g., a coating process, a silk-screen process, and a photolithography process, processes for separately manufacturing the pixel units and mounting the pixel units on the separate substrate are not necessary.
In the conventional art, a light emitting apparatus is completed by separately manufacturing a light emitting device chip, separately manufacturing a PCB substrate on which a terminal part and wirings are formed, and attaching the light emitting device chip to the PCB substrate using a conductive paste. In this case, the terminal part and the wirings are formed on the PCB substrate through complex processes of forming thru-holes penetrating through top and bottom of the PCB substrate and forming additional electrode and connection wirings, which are electrically connected to each other through the thru-holes. In addition, since areas are additionally required in the PCB substrate to form the thru-holes, it is difficult to miniaturize pixels. The areas for the thru-holes may be reduced by decreasing a diameter of the thru-holes, however in this case, it is difficult to form the thru-holes due to the decreased diameter of the thru-holes, and a difficulty and a cost in fabricating sharply increase.
In contrast, the light emitting apparatus according to the exemplary embodiment is manufactured by forming the contact holes through the insulation layer without employing the separate printed circuit board and connecting the terminal part through the contact holes. Thus, the pixel may be miniaturized, and the light emitting apparatus may be simply manufactured at a low cost.
In the above drawings, the light emitting apparatus is shown with respect to one pixel unit, however plural pixel units may be substantially simultaneously formed on a large-sized substrate, and the large-sized substrate may be divided into individual display units of various sizes through a cutting process. The term “display unit” means a unit in which one or plural pixel units are mounted on one substrate. The divided individual display units are assembled and mounted on a base substrate on which wirings or driving circuits are mounted, for example, on the printed circuit board, and thus the light emitting apparatus or displaying apparatus of various sizes may be manufactured.
According to the exemplary embodiment, the manufacturing method of the displaying apparatus includes the transferring method of stably and efficiently transferring plural light emitting devices.
Referring to
The green light emitting devices 150G and the blue light emitting devices 150B, which are formed on the separate temporary substrate 10p, are transferred onto a third temporary substrate 10r using a conveying apparatus 190. The third temporary substrate 10r may have heat resistance, flexibility, and/or viscosity and may be provided in the form of sheet. The third temporary substrate 10r is a temporary substrate on which the light emitting devices are temporarily aligned before the blue light emitting devices 150B or the green light emitting devices 150G are transferred onto a final substrate.
The light emitting devices 150, which are to be finally mounted, are arranged on the third temporary substrate 10r to correspond to the pixels.
An additional process, e.g., a process of forming the electrode part, may be performed on the light emitting devices 150 on the third temporary substrate 10r. A temporary adhesive layer 183 is provided on the third temporary substrate 10r, the light emitting devices 150 is attached on the temporary adhesive layer.
Referring to
The third temporary substrate 10r on which the light emitting devices 150 are formed is gripped by the conveying apparatus 190 and inverted to face the substrate 10 with the light emitting devices 150 interposed therebetween.
Referring to
Referring to
According to the above-described embodiment, it is possible to manufacture the display apparatus in which the defects, for example, the light emitting devices are separated from their locations or the light emitting devices are inclinedly attached, are prevented as much as possible.
Referring to
Referring to
Referring to
The displaying apparatus may include the display units 101 assembled to include the pixel units 110. In the exemplary embodiment, each pixel unit 110 may include a green pixel, a red pixel, and a blue pixel, and the first, second, and third pixels 111a, 111b, and 111c may correspond to the green pixel, the red pixel, and the blue pixel, respectively. However, the pixel included in each pixel unit should not be limited thereto or thereby. For instance, each pixel unit may include a cyan pixel, a magenta pixel, and a yellow pixel.
The pixel units 110 and/or the pixels 111a, 111b, and 111c are arranged in a matrix form. The expression that the pixel units 110 and/or the pixels 111a, 111b, and 111c are arranged in the matrix form does not indicate only that the pixel units 110 and/or the pixels 111a, 111b, and 111c are arranged exactly in line along rows or columns, and detailed locations of the pixel units 110 and/or the pixels 111a, 111b, and 111c may be changed while being arranged along the rows or columns taken as a whole, such as a zigzag form.
Referring to
The timing controller 350 receives various control signals and image data, which are required to drive the displaying apparatus, from an external source (e.g., a system that transmits the image data). The timing controller 350 rearranges the received image data and applies the rearranged image data to the data driver 330. In addition, the timing controller 350 generates scan control signals and data control signals, which are required to drive the scan driver 310 and the data driver 330, and applies the generated scan control signals and the data control signals to the scan driver 310 and the data driver 330, respectively.
The scan driver 310 receives the scan control signals from the timing controller 350 and generates scan signals in response to the scan control signals.
The data driver 330 receives the data control signals from the timing controller 350 and generates data signals in response to the data control signals.
The line part includes a plurality of signal lines. In detail, the line part includes first lines 103 that connect the scan driver 310 and the pixels and second lines 102 that connect the data driver 330 and the pixels. In the exemplary embodiment, the first lines 103 may be scan lines, and the second lines 102 may be data lines. Accordingly, hereinafter the first lines and the second lines will be described as the scan lines and the data lines, respectively. In addition, the line part may further include lines that connect the timing controller 350 and the scan driver 310, the timing controller 350 and the data driver 330, or other components to each other to transmit signals.
The scan lines 103 transmit the scan signals generated by the scan driver 310 to the pixels. The data signals generated by the data driver 330 are applied to the data lines 102. The data signals applied to the data lines 102 are input to pixels of a horizontal pixel unit line selected by the scan signal.
The pixels 111a, 111b, and 111c are connected to the scan lines 103 and the data lines 102. The pixels 111a, 111b, and 111c selectively emit the light in response to the data signals provided from the data lines 102 when the scan signals from the scan lines 103 are applied thereto. As an example, each of the pixels 111a, 111b, and 111c emits the light at a brightness corresponding to the data signal applied thereto during each frame period. The pixels 111a, 111b, and 111c, to which the data signals corresponding to a black brightness are applied, do not emit the light during corresponding frame period.
In the exemplary embodiment, the pixels 111a, 111b, and 111c may be driven in passive matrix or active matrix manners. When the displaying apparatus is driven in the active matrix manner, the displaying apparatus may be driven by being further supplied with first and second power sources in addition to the scan signals and the data signals.
Referring to
When a voltage equal to or greater than a threshold voltage is applied to between the first electrode and the second electrode, the light emitting device 150 emits the light at a brightness corresponding to a level of the voltage applied thereto. That is, the light emission of the first pixel 111a may be controlled by controlling a voltage of the scan signal applied to the scan line 103 and/or a voltage of the data signal applied to the data line 102.
In the exemplary embodiment, one light emitting device 150 connected between the scan line 103 and the data line 102 is shown, but the number of the light emitting devices 150 connected between the scan line 103 and the data line 102 should not be limited to one. That is, plural light emitting devices 150 may be connected between the scan line 103 and the data line 102, and in this case, the light emitting devices 150 may be connected to each other in parallel or series.
Referring to
A first electrode of the light emitting device 150 is connected to the first pixel power source ELVDD via the transistor part TFT, and a second electrode of the light emitting device 150 is connected to the second pixel power source ELVSS. The first pixel power source ELVDD and the second pixel power source ELVSS may have different electric potentials from each other. As an example, the second pixel power source ELVSS may have the electric potential lower than the electric potential of the first pixel power source ELVDD by the threshold voltage of the light emitting device 150 or more. Each of the light emitting devices 150 emits the light at a brightness corresponding to a driving current controlled by the transistor part TFT.
According to the exemplary embodiment, the transistor part TFT includes first and second transistors M1 and M2 and a storage capacitor Cst. However, a configuration of the transistor part TFT should not be limited to the embodiment shown in
The first transistor M1 (switching transistor) includes a source electrode connected to the data line 102, a drain electrode connected to a first node N1, and a gate electrode connected to the scan line 103. The first transistor M1 is turned on upon receiving the scan signal having the voltage sufficient to turn on the first transistor M1 through the scan line 103 to electrically connect the data line 102 and the first node Ni. In this case, the data signal of the corresponding frame is applied to the data line 102, and thus the data signal is applied to the first node N1. The storage capacitor Cst is charged with the data signal applied to the first node N1.
The second transistor M2 (driving transistor) includes a source electrode connected to the first pixel power source ELVDD, a drain electrode connected to the first electrode of the light emitting device, and a gate electrode connected to the first node N1. The second transistor M2 controls an amount of the driving current supplied to the light emitting device 150 in response to the voltage of the first node N1.
One electrode of the storage capacitor Cst is connected to the first pixel power source ELVDD, and the other electrode of the storage capacitor Cst is connected to the first node N1. The storage capacitor Cst is charged with the voltage corresponding to the data signal applied to the first node N1 and maintains the charged voltage until a data signal of a next frame is provided.
For the convenience of explanation,
According to the exemplary embodiment, the large-sized displaying apparatus may be implemented by the displaying apparatus according to the above-described embodiments alone, however, when regarding the displaying apparatus according to the above-described embodiments as one display module, it is possible to implement a displaying apparatus with a larger area than that of the conventional displaying apparatus by assembling a plurality of display modules to each other.
Referring to
In the present exemplary embodiment, each of the display modules DM or at least some display modules may be independently driven. As another way, at least some display modules DM may be dependently driven in conjunction with other display modules DM. In the case where the display modules DM are driven in conjunction with each other, one image may be displayed as shown in
In the present exemplary embodiment, the display modules DM have the same size as each other, however the present disclosure should not be limited thereto or thereby. That is, at least one display module DM may have a size different from that of the other display modules DM. In addition, at least one display module DM may have a different number of pixels from that of the other display modules DM, and thus they may have different resolutions from each other. Further, in a case where the resolution of all areas does not need to be the same, the multi-module displaying apparatus may be manufactured by arranging the display modules DM having different resolutions from each other.
Referring to
The panel substrate 210 may comprise a circuit for a passive matrix drive or an active matrix drive. In one exemplary embodiment, the panel substrate 210 may comprise wires and resistors therein, and in another embodiment, the panel substrate 210 may comprise wires, transistors, and capacitors. The panel substrate 210 may also have pads on its top surface allowing electrical access to the disposed circuit. Although the present disclosure describes that the panel substrate 210 comprises the circuit, the panel substrate 210 may be a transparent substrate capable of transmitting light.
The plurality of light emitting devices 800 are arranged on the panel substrate 210. Each light emitting device 800 may constitute one subpixel SP. The light emitting device 800 has first and second electrode pads 112 and 114, and the first and second electrode pads 112 and 114 may be electrically connected to the panel substrate 210.
In the present disclosure, the light emitting devices 800 may comprise a blue light emitting device 802, a green light emitting device 804, and a red light emitting device 806. The blue light emitting device 802 may be an inorganic light emitting diode emitting blue light and may comprise an AlGaInN-based well layer. The green light emitting device 804 may be an inorganic light emitting diode emitting green light, and may comprise an AlGaInP-based well layer or an AlInGaN-based well layer. The red light emitting device 806 may be an inorganic light emitting diode emitting red light, and may comprise an AlGaInP-based well layer. Furthermore, the light emitting devices 800 are not limited to the light emitting devices 802, 804, and 806 emitting light of a single color, and one light emitting device 800 may have a plurality of well layers having a stacked structure so as to emit light of various colors such as blue, green, and red.
In the present disclosure, the blue light emitting device 802, the green light emitting device 804, and the red light emitting device 806 are disposed in different subpixels SPs, respectively and one or more light emitting devices may be disposed in one subpixel SP. Three subpixels SPs in which the blue light emitting device 802, the green light emitting device 804 and the red light emitting device 806 are disposed, respectively, may form one pixel P.
A specific example of the light emitting device 800 will be described with reference to
Referring to
The light emitting structure 29 comprises a first conductivity type semiconductor layer 23, an active layer 25, and a second conductivity type semiconductor layer 27. The active layer 25 may be disposed on the first conductivity type semiconductor layer 23, and the second conductivity type semiconductor layer 27 may be disposed on the active layer 25.
The active layer 25 may have a multi-quantum well structure in particular. A wavelength of light emitted by the light emitting device 800 may be varied according to a composition of the active layer 25, and thus it may become a blue light emitting device 802, a green light emitting device 804, or a red light emitting device 806.
In addition, the first conductivity type semiconductor layer 23 may be an n-type semiconductor layer, and the second conductivity type semiconductor layer 27 may be a p-type semiconductor layer. In the present disclosure, a mesa M may be formed over the first conductivity type semiconductor layer 23. The mesa M may be formed by etching the active layer 25 and the second conductivity type semiconductor layer 27, and may comprise a portion of the first conductivity type semiconductor layer 23.
The ohmic-layer 33 may be disposed on the second conductivity type semiconductor layer 27. The ohmic-layer 33 is in ohmic contact with the second conductivity type semiconductor layer 27. The ohmic-layer 33 may comprise a reflection layer, and the reflection layer reflects light generated in the active layer 25 to prevent the light from being absorbed by the first and second electrode pads 112 and 114 or a substrate and lost. In one example, the ohmic-layer 33 may comprise an ohmic-contact layer and a reflection layer. However, the present disclosure is not limited thereto, but the ohmic-layer 33 may be formed of a transparent metal layer or a transparent conductive oxide layer.
The insulation layer 31 may cover the ohmic-layer 33 and the mesa M, and may also cover a portion of an upper surface and sides of the first conductivity type semiconductor layer 23. As it will be described later, the insulation layer 31 may cover sides of a via hole formed for allowing the first electrode pad 112 to be electrically connected to the first conductivity type semiconductor layer 23. The insulation layer 31 may be formed of a single layer or multiple layers of a silicon oxide layer or a silicon nitride layer. Furthermore, the insulation layer 31 may be formed of a distributed Bragg reflector.
The first electrode pad 112 is electrically connected to the first conductivity type semiconductor layer 23. As illustrated in
The second electrode pad 114 is electrically connected to the second conductivity type semiconductor layer 27. The second electrode pad 114 may be disposed over the insulation layer 31, and electrically connected to the ohmic-layer 33 through an opening formed in the insulation layer 31. In the present disclosure, the ohmic-layer 33 is formed of a conductive material, and electrically connects the second electrode pad 114 to the second conductivity type semiconductor layer 27.
One or more connection tips 55b may be disposed over the insulation layer 31, and may be disposed between the first electrode pad 112 and the second electrode pad 114. The connection tip 55b may be formed in a process of transferring the light emitting device 800 to the panel substrate 210. An upper surface of the connection tip 55b may not be a flat surface but a generally irregular inclined surface, and may have an uneven structure. In addition, a plurality of connection tips 55b disposed on one light emitting device 800 may have different lengths one another. In the present disclosure, the connection tip 55b may comprise an organic material such as poly dimethylpolysiloxane (PDMS), epoxy, acryl, color polyimide, or others. However, the present disclosure is not limited thereto, but the connection tip 55b may comprise a material other than an organic material.
In the present disclosure, the plurality of connection tips 55b may be disposed on the light emitting device 800, and the plurality of connection tips 55b may be arranged asymmetrically to a particular direction. For example, as shown in
Referring to
As shown, since the ohmic-layer 33 is omitted, a second electrode pad 114 may be electrically connected directly to a second conductivity type semiconductor layer 27. Since the light emitting device 800′ has a relatively small size, current can be evenly spread over a wide area of the light emitting device 800′ even if the ohmic-layer 33 is omitted.
In the meantime, although the connection tip 55b in the above exemplary embodiment is illustrated and described as formed on the same side as the surface where the first and second electrode pads 112 and 114 are disposed on, the connection tip 55b may be formed on an opposite side of the light emitting device 800 to the first and second electrode pads 112 and 114. Formation of the connection tip 55b under the light emitting device 800 is related to a method of transferring the light emitting devices 800, and can be understood through a later description of a method of transferring the light emitting devices 800.
Referring to
Referring to
Referring to
The first mask layer 53 may be formed of a photosensitive material, and the plurality of holes Hs may be formed through a photolithography process. The plurality of holes Hs may be formed through an exposure and development processes, but the present disclosure is not necessarily limited thereto, but an etching process may be used. The plurality of holes Hs may be formed in a triangular shape as shown in the drawing. However, the number of holes Hs is not necessarily limited to three.
Referring to
The connection layer 55 may be formed of an organic material such as poly dimethylpolysiloxane (PDMS), epoxy, acryl, color polyimide, or the like, but it is not limited thereto. Here, the connection layer 55 may have a light transmittance of 90% or more, and a refractive index may be 1.4 to 1.7.
Referring to
When the first temporary substrate 57 is coupled to the connection layer 55, the substrate 51 is removed from the light emitting devices 800 as in
Referring to
Referring to
When coupling the second temporary substrate 59 to the light emitting devices 800 is completed, the light emitting devices 800 are removed from the connection layer 55 by using the second temporary substrate 59 as shown in
The external force applied to the second temporary substrate 59 as shown in the drawing, may be applied in a direction perpendicular to the connection layer 55 at one side of the second temporary substrate 59. Accordingly, each of the light emitting devices 800 may be separated from the connection layer 55 in such a manner that the at least one connection portion 55a connected to each light emitting device 800 is sequentially cut from one side of the second temporary substrate 59.
Referring to
Referring to
The pickup 70 picks up and transfers a portion of the plurality of light emitting devices 800, and selectively picks up the light emitting devices 800 arranged in accordance with an interval of the panel substrate 210. Accordingly, as shown in the drawing, the pickup 70 doesn't pick up adjacent light emitting devices 800 together, but picks up the light emitting devices 800 at a certain interval at a time. The interval of the light emitting devices 800 to be picked up may vary depending on an interval of pixels in the panel substrate 210 onto which the light emitting devices 800 is transferred.
The pickup 70 picks up the light emitting devices 800 disposed with an interval matching an interval of the pixels Ps shown in
In the present disclosure, the light emitting devices 800 may be picked up with the first and second electrode pads 112 and 114 disposed thereon. Accordingly, an additional temporary substrate may be used in a process of mounting the light emitting devices 800 on the panel substrate 210 by using the pickup 70. That is, the light emitting devices 800 picked up through the pickup 70 may be first arranged on the additional temporary substrate at the interval of the pixels Ps. The blue light emitting device 802, the green light emitting device 804, and the red light emitting device 806 may be all arranged on the additional temporary substrate at the interval of the pixels Ps. The blue light emitting devices 802, the green light emitting devices 804, and the red light emitting devices 806 disposed on the additional temporary substrate may be transferred to the panel substrate 210 at once. The light emitting devices 800 may be transferred for the first and second electrode pads 112 and 114 to be bonded to the panel substrate 210.
Referring to
Referring to
Subsequently, referring to
The first mask layer 53 may be formed of a photosensitive material, and the plurality of holes Hs may be formed through a photolithography process. For example, the holes Hs may be formed through an exposure and development processes, but it is not limited thereto, but an etching process may be used. The plurality of holes Hs may be formed in a triangular shape as shown in the drawing.
Referring to
The connection layer 55 may be formed of an organic material such as poly dimethylpolysiloxane (PDMS), epoxy, acryl, color polyimide, or the like, but it is not limited thereto. Here, the coupling layer 55 may have a light transmittance of 90% or more, and a refractive index may be 1.4 to 1.7.
Referring to
When the first temporary substrate 57 is coupled to the upper surface of the connection layer 55, bubbles generated in the connection layer 55 in a vacuum state may be removed, and a hardening process of the connection layer 55 may be performed at a temperature lower than a melting point of the first mask layer 53. In this process, the first temporary substrate 57 may be coupled to the connection layer 55.
Referring to
Referring to
Referring to
Referring to
When the second temporary substrate 59 is coupled to the light emitting devices 800, the light emitting devices 800 are removed from the connection layer 55 by using the second temporary substrate 59 as shown in
The external force applied to the second temporary substrate 59 as shown in the drawing, may be applied in a direction perpendicular to the connection layer 55 at one side of the second temporary substrate 59. Accordingly, each of the light emitting devices 800 may be separated from the connection layer 55 in such a manner that the connection portions 55a connected to each light emitting device 800 is sequentially cut.
Referring to
And referring to
Referring to
Referring to
Referring to
Referring to
Referring to
Referring to
The second mask layer 65 may be formed with a photosensitive material as the first mask layer 53, and the plurality of holes Hs may be formed by a photolithography process. The plurality of holes Hs may be formed in a triangular shape as shown in the drawing.
Referring to
The connection layer 55 may comprise an organic material such as poly dimethylpolysiloxane (PDMS), epoxy, acryl, color polyimide, or the like, but it is not limited thereto. Here, the coupling layer 55 may have a light transmittance of 90% or more, and a refractive index may be 1.4 to 1.7.
And a second temporary substrate 59 is coupled to a lower surface of the connection layer 55. The second temporary substrate 59 may be a polymer substrate the same as the first temporary substrate 57 such as PET, PEN, PI sheet, or others, or may be a substrate such as glass, PC, PMMA, or others.
Referring to
Referring to
Once the first and second mask layers 53 and 65 are removed, the light emitting devices 800 are disposed over the second temporary substrate 59 while being connected to the connection layer 55 and the connection portion 55a as shown in
Referring to
In light emitting devices 800 according to the modified examples shown in
Referring to
Referring to
And a total area of the three connection tips 55b may be 0.65% as compared with the planar area of the light emitting device 800.
Referring to
Here, the connection tips 55b may be formed in a diamond shape, and the four connection tips 55b may be disposed at each corner of the diamond shape. At this time, a total area of the four connection tips 55b may be 1.22% as compared with the planar area of the light emitting device 800.
Referring to
Each of the connection tips 55b may be formed in a diamond shape, and the four connection tips 55b may be disposed at each corner of the diamond shape. At this time, a total area of the four connection tips 55b may be 1.22% as compared with the planar area of the light emitting device 800.
Referring to
Referring to
Referring to
A total area of the three connection tips 55b may be 0.58% as compared with the planar area of the light emitting device 800.
Referring to
Referring to
Referring to
Referring to
Referring to
At this time, a total area of the connection tip 55b may be 1.92% as compared with the planar area of the light emitting device 800.
Referring to
At this time, a total area of the connection tip 55b may be 1.161% as compared with the planar area of the light emitting device 800.
Referring to
Referring to
The two connection tips disposed at the locations overlapped with the second electrode pad 114 may be disposed near one edge of the second electrode pad 114, and may be disposed to be opposite to each other with respect to an elongated straight line passing through the center.
In the meantime, the one connection tip disposed at the location overlapped with the first electrode pad 112 may be disposed near one edge of the first electrode pad 112, and may be disposed apart from the elongated straight line passing through the center.
Each of the connection tips may have a right triangular shape, and the connection tip disposed at the center of the light emitting device 800 may be disposed in a direction opposite to the other connection tips as shown in the drawing.
When the light emitting devices are separated from the connection layer using the connection tips, the connection tip overlapped with the first electrode pad 112 may be formed first, then the connection tip near the center may be formed, and the connection tips overlapped with the second electrode pad 114 may be formed last. Accordingly, the light emitting devices may be easily separated from the connection layer, and it is possible to prevent cracks that may occur in the light emitting device.
Furthermore, when the light emitting device 800 is picked up or mounted, the light emitting device 800 may be unstably picked up or mounted depending on locations of the connection tips, and thus cracks may be caused. On the contrary, by arranging the connection tips at both side edges of the light emitting device 800 and near the center of the light emitting device 800, respectively, the light emitting device 800 may be stably picked up or mounted, and it is possible to prevent cracks that may occur in the light emitting device.
A total area of the four connection tips 55b may be 0.8% as compared with the planar area of the light emitting device 800.
When areas of the connection tips 55b formed in the light emitting device 800 are formed to be different from one another, Table 1 shows a comparison between area ratios of the connection tips 55b and success probabilities of picking up the light emitting device 800.
Through the first to fifteenth modified examples, it is confirmed that the pick-up success rate of the light emitting devices 800 is satisfactory when the area ratio of the connection tips 55b is about 1.2% or less as compared with the planar area of the light emitting device 800.
Referring to
The first conductivity type semiconductor layer 2110, the active layer 2112, and the second conductivity type semiconductor layer 2114 may be grown on a substrate. The substrate may be a variety of substrates capable of growing semiconductors such as a gallium nitride substrate, a GaAs substrate, a Si substrate, a sapphire substrate, especially a patterned sapphire substrate, or others. The growth substrate may be separated from the semiconductor layers using techniques such as mechanical polishing, laser lift off, chemical lift off, or others. However, the present disclosure is not limited thereto, and a portion of the substrate may remain to form at least a portion of the first conductivity type semiconductor layer 2110.
In the case of a light emitting device emitting green light, semiconductor layers may comprise indium gallium nitride (InGaN), gallium nitride (GaN), gallium phosphide (GaP), aluminum gallium indium phosphide (AlGaInP), or aluminum gallium phosphide (AlGaP). In one exemplary embodiment, in the case of a light emitting device emitting red light, semiconductor layers may comprise aluminum gallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide, or gallium phosphide (GaP). In one exemplary embodiment, in the case of a light emitting device emitting blue light, a semiconductor layer may comprise gallium nitride (GaN), indium gallium nitride (InGaN), or zinc selenide (ZnSe).
The semiconductor layers comprise specifically the first conductivity type semiconductor layer 2110, the active layer 2112, and the second conductivity type semiconductor layer 2114. As the first conductivity type and the second conductivity type are opposite in polarity, when the first conductivity type is n-type, the second conductivity type is p, and when the second conductivity type is p-type, the second conductivity type is n-type
The first conductivity type semiconductor layer 2110, the active layer 2112 and the second conductivity type semiconductor layer 2114 may be formed on a substrate in a chamber using a known method such as metal organic chemical vapor deposition (MOCVD). In addition, the first conductivity type semiconductor layer 2110 comprises n-type impurities (for example, Si, Ge, and Sn), and the second conductivity type semiconductor layer 2114 comprises p-type impurities (for example, Mg, Sr and Ba). In one exemplary embodiment, the first conductivity type semiconductor layer 2110 may comprise GaN or AlGaN containing Si as a dopant, and the second conductivity type semiconductor layer 2114 may comprise GaN or AlGaN containing Mg as a dopant.
Although each of the first conductivity type semiconductor layer 2110 and the second conductivity type semiconductor layer 2114 is illustrated as a single layer in the drawings, these layers may be multiple layers, or may comprise superlattice layers. The active layer 2112 may comprise a single quantum well structure or a multiple quantum well structure, and a composition ratio of a nitride-based semiconductor is adjusted to emit a desired wavelength. For example, the active layer 2112 may emit blue light, green light, red light, or ultraviolet light.
The second conductivity type semiconductor layer 2114 and the active layer 2112 have a mesa (M) structure and are disposed on the first conductivity type semiconductor layer 2110. The mesa M may comprise the second conductivity type semiconductor layer 2114 and the active layer 2112, and may comprise a portion of the first conductivity type semiconductor layer 2110 as shown in
In addition, the mesa M may have a through hole 2114a exposing the first conductivity type semiconductor layer 2110. The through hole 2114a may be disposed close to one side edge of the mesa M, but the present disclosure is not limited thereto, the through hole 2114a may be disposed at a center of the mesa M.
The ohmic-contact layer 2116 is disposed on the second conductivity type semiconductor layer 2114 to be in ohmic-contact with the second conductivity type semiconductor layer 2114. The ohmic-contact layer 2116 may be formed as a single layer or a multiple layer, or may be formed of a transparent conductive oxide layer or a metal layer. Examples of the transparent conductive oxide layers include ITO, ZnO or others, and examples of the metal layers include metals such as Al, Ti, Cr, N1, Au, or an alloy thereof.
The insulation layer 2120 covers the mesa M and the ohmic-contact layer 2116. Further, the insulation layer 2120 may cover an upper surface and side surfaces of the first conductivity type semiconductor layer 2110 exposed around the mesa M. In the meantime, the insulation layer 2120 may have an opening 2120a exposing the ohmic-contact layer 2116 and an opening 2120b exposing the first conductivity type semiconductor layer 2110 in the through hole 2114a. The insulation layer 2120 may be formed of a single- or multi-layer of a silicon oxide layer or a silicon nitride layer. In addition, the insulation layer 2120 may comprise an insulated reflector, such as a distributed Bragg reflector.
The first terminal 2122 and the second terminal 2124 are disposed on the insulation layer 2120. The first terminal 2122 may be electrically connected to the ohmic-contact layer 2116 through the opening 2120a, and the second terminal 2124 may be electrically connected to the first conductivity type semiconductor layer 2110 through the opening 2120b.
The first and/or second terminals 2122 and 2124 may have a single-, or a multi-layer metal. The first and/or second terminals 2122 and 2124 may include metals such as Al, Ti, Cr, N1, Au, or an alloy thereof.
In the meantime, the connection tips 55b may be disposed as described with reference to
In the exemplary embodiment, the light emitting device 811 is roughly described with reference to drawings. The light emitting device 811 may further include a layer with additional functionality in addition to the above-mentioned layers. For instance, various layers, such as a reflection layer that reflects the light, an additional insulation layer that insulates specific components, and a solder prevention layer that prevents a solder from being diffused, may be included in the light emitting device 811.
In addition, when a flip-chip type light emitting device is formed, a mesa may be formed in various shapes, locations and shapes of the first and second terminals 2122 and 2124 may be variously changed. In addition, the ohmic-contact layer 2116 may be omitted, and the first terminal 2122 may directly contact the second conductivity type semiconductor layer 2114. Further, a second contact layer may be formed on the first conductivity type semiconductor layer 2110, and the second terminal 2124 may be connected to the second contact layer as in the case of the light emitting devices 511 and 611 described above.
Referring to
In the present exemplary embodiment, the base substrate 900 does not include a circuit. The base substrate 900 is a light-transmitting substrate such as a glass substrate, a quartz substrate, or a sapphire substrate.
Although a single pixel region Pa is shown here, a plurality of pixels P may be formed on the single base substrate 900.
The base substrate 900 is disposed on a light emitting surface of the displaying apparatus and light emitted from the light emitting devices 811, 813, and 815 is emitted to outside through the base substrate 900. The base substrate 900 may have projections and depressions PR on the light emitting surface, and light emission efficiency may be improved through the projections and depressions PR, and more uniform light may be emitted. The base substrate 900 may have a thickness of, for example, 50 um to 500 um.
The light blocking layer 902 may comprise an absorbing material that absorbs light, such as carbon black. The light absorbing material prevents the light generated in the light emitting devices 811, 813 and 815 from leaking to a side in a region between the base substrate 900 and the light emitting devices 811, 813 and 815, and thus contrast of the displaying apparatus may be improved.
The light blocking layer 902 may have a window for providing a light path so that the light generated in the light devices 811, 813, and 815 is incident on the base substrate 900. For this purpose, the light blocking layer 902 may be subjected to patterning to expose the base substrate 900. A width of the window may be smaller than that of the light emitting device.
The adhesive layer 903 is attached on the base substrate 900. The adhesive layer 903 may be attached to the entire surface of the base substrate 900, and used to attach the light emitting devices 811, 813, and 815. The adhesive layer 903 may fill the window formed in the light blocking layer 902.
The adhesive layer 903 transmits light emitted from the light emitting devices 811, 813, and 815 to a light-transmitting layer. The adhesive layer 903 may comprise diffusers such as SiO2, TiO2, or ZnO to diffuse light. The light diffusing material prevents the light emitting devices 811, 813, and 815 from being observed from the light emitting surface.
The alignment markers 901 (shown in
In the meantime, each of the first to third light emitting devices 811, 813, and 815 are disposed on regions formed by the alignment markers 901. The first to third light emitting devices 811, 813 and 815 may be a green light emitting device, a red light emitting device, or a blue light emitting device, for example. In the present exemplary embodiment, the first to third light emitting devices 811, 813 and 815 are illustrated as arranged in a triangle, but the present disclosure is not limited thereto, they may be arranged linear.
The first to third light emitting devices 811, 813, and 815 may be those described above with reference to
The step adjustment layer 905 covers the first to third light emitting devices 811, 813, and 815. The step adjustment layer 905 has openings 905a exposing the first and second terminals 2122 and 2124 of the light emitting devices. The step adjustment layer 905 may be formed to equalize a height of a location where the bumps are formed when forming the bumps. The step adjustment layer 905 may be formed of polyimide, for example.
Connection layers 907a and 907c are formed on the step adjustment layer 905. Connection layers 907a, 907b, and 907c are electrically connected to the first and second terminals 2122 and 2122 of the first to third light emitting devices 811, 813, and 815 through the openings 905a of the step adjustment layer 905.
For example, the connection layers 907a are electrically connected to the first conductivity type semiconductor layer of the second light emitting device 813, and the connection layer 907c is electrically connected to the second conductivity type semiconductor layers of the first to third light emitting devices 811, 813, and 185. The connection layers 907a and 907c may be formed together on the step adjustment layer 905, and may include Au, for example.
Bumps 921, 923, 925, and 930 are formed on the connection layers 907a. For example, the first bump 921 may be electrically connected to the first conductivity type semiconductor layer of the first light emitting device 811 through the connection layer 907a, and the second bump 923 may be electrically connected to the first conductivity type semiconductor layer of the second light emitting device 813 through the connection layer 907a, and the third bump 925 may be electrically connected to the first conductivity type semiconductor layer of the third light emitting device 815 through the connection layer 907a. In the meantime, the fourth bump 930 may be commonly connected to the second conductivity type semiconductor layers of the first to third light emitting devices 811, 813, and 815 through the connection layer 907c. The bumps 921, 923, 925, and 930 may be formed of a solder for example.
In the meantime, a protection layer 909 may cover side surfaces of the bumps 921, 923, 925, and 930, and may cover the step adjustment layer 905. Further, the protection layer 909 may cover the adhesive layer 903 exposed around the step adjustment layer 905. The protection layer 909 may be formed of a photosensitive solder resist (PSR), for example, and thus the bumps 921, 923, 925, and 930 may be formed after patterning the protection layer 909 through photolithography and development. The protection layer 909 may also be formed of a light-absorbing material such as a white reflective material or black epoxy to prevent light leakage.
Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concepts are not limited to such embodiments, but rather to the broader scope of the appended claims and various obvious modifications and equivalent arrangements as would be apparent to a person of ordinary skill in the art.
This application is a Continuation of U.S. patent application Ser. No. 17/353,699, filed on Jun. 21, 2021, which is a Continuation of U.S. patent application Ser. No. 16/904,081, filed on Jun. 17, 2020, issued as U.S. Pat. No. 11,043,476, which is a Continuation of U.S. patent application Ser. No. 16/207,692, filed on Dec. 3, 2018, issued as U.S. Pat. No. 10,797,027, and which claims priority from and the benefit of U.S. Provisional Application No. 62/595,010, filed on Dec. 5, 2017, U.S. Provisional Application No. 62/610,489, filed on Dec. 26, 2017, and U.S. Provisional Application No. 62/694,353, filed on Jul. 5, 2018, all of which are hereby incorporated by reference for all purposes as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 62694353 | Jul 2018 | US | |
| 62610489 | Dec 2017 | US | |
| 62595010 | Dec 2017 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17353699 | Jun 2021 | US |
| Child | 18123321 | US | |
| Parent | 16904081 | Jun 2020 | US |
| Child | 17353699 | US | |
| Parent | 16207692 | Dec 2018 | US |
| Child | 16904081 | US |
