The present disclosure relates to display devices, and in particular to display devices that include light-emitting diodes.
As digital technology develops, display devices are being used more widely in our society. For example, display devices have been applied in modern information and communication devices such as televisions, notebooks, computers, and mobile phones (e.g., smartphones). In addition, each generation of display devices has been developed to be thinner, lighter, smaller, and more fashionable than the previous generation.
Among the various types of display devices available, light-emitting diode (LED) display devices are gaining in popularity, since LEDs have such advantages as high efficiency and a long life span.
However, existing LED display devices have not been satisfactory in every respect.
Some embodiments of the present disclosure provide a display device. The display device includes a first light-emitting diode. The first light-emitting diode includes a first conductive pad, a second conductive pad adjacent to the first conductive pad, and a first light-emitting portion on the first conductive pad. The display device also includes a second light-emitting diode. The second light-emitting diode includes a third conductive pad, a fourth conductive pad adjacent to the third conductive pad, and a second light-emitting portion on the third conductive pad. A distance between the first conductive pad and the third conductive pad is less than a distance between the second conductive pad and the fourth conductive pad.
Some embodiments of the present disclosure provide a light-emitting diode. The light-emitting diode includes a semiconductor layer. The semiconductor layer has a first side. The light-emitting diode also includes a first conductive pad on the semiconductor layer, and a second conductive pad on the semiconductor layer. A distance between the first conductive pad and the first side is less than or equal to 25 micrometer.
Some embodiments of the present disclosure provide a display device. The display device includes a substrate. The substrate includes a first bonding pad. The display device also includes a light-emitting diode. The light-emitting diode includes a first conductive pad. The first conductive pad is electrically connected to the first bonding pad. The display device also includes a conductive adhesive layer disposed between the substrate and the light-emitting diode. The conductive adhesive layer includes at least one of In, Ag, or Sn.
A detailed description is given in the following embodiments with reference to the accompanying drawings.
The disclosure can be more fully understood from the following detailed description when read with the accompanying figures. It is worth noting that in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter provided. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact.
In addition, the present disclosure may repeat reference numerals and/or letters in the various embodiments. This repetition is for simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Some embodiments of the present disclosure will be described below. Additional operations may be provided before, during, and/or after the steps described in these embodiments. Some of the steps described may be replaced or omitted in different embodiments. In addition, although some embodiments of the present disclosure will be discussed in the following paragraphs with several steps in a specific order, these steps may be performed in other reasonable orders.
The arrangement of the light-emitting diodes of the display device of Embodiment 1 may increase the contrast ratio of the display device, and the details will be discussed in the following paragraphs.
As shown in
Still referring to
Now referring to
For example, each of the semiconductor layer 102a and the semiconductor layer 102b may be made of GaN, AlGaN, AlN, GaAs, GaInP, AlGaAs, InP, InAlAs, InGaAs, AlGaInP, other applicable III-V group semiconductor materials, or a combination thereof, but the present disclosure is not limited thereto. The light-emitting portion 102e may be made of GaN, AlGaN, AlN, GaAs, GaInP, AlGaAs, InP, InAlAs, InGaAs, AlGaInP, other applicable III-V group semiconductor materials, or a combination thereof, but the present disclosure is not limited thereto. In some embodiments, the light-emitting portion 102e may include a quantum well structure. In some embodiments, the recombination rate of the electrons and the holes in the quantum well structure discussed above is high, thus increasing the light-emitting efficiency of the display device 10.
For example, an epitaxial process may be used to form the semiconductor layer 102a, the light-emitting portion 102e and the semiconductor layer 102b on an applicable epitaxial substrate (not shown in the figures), and the epitaxial substrate may be removed after the light-emitting diode 102 is bonded onto the substrate 100. For example, the epitaxial substrate may include sapphire substrate, SiC substrate, Si substrate, MgAl2O4 substrate, MgO substrate, LiAlO2 substrate, LiGaO2 substrate, GaN substrate, GaAs substrate, GaP substrate, glass substrate, other applicable substrates, or a combination thereof, but the present disclosure is not limited thereto. For example, the epitaxial process may include a molecular-beam epitaxy (MBE) process, a metalorganic chemical vapor deposition (MOCVD) process, a hydride vapor phase epitaxy (HVPE) process, another applicable epitaxial process, or a combination thereof, but the present disclosure is not limited thereto.
In some embodiments, the conductive type of the dopants doped in the semiconductor layer 102a and the conductive type of the dopants doped in the semiconductor layer 102b may be opposite to each other (e.g., the semiconductor layer 102a may be doped with n-type dopants, and the semiconductor layer 102b may be doped with p-type dopants). For example, the semiconductor layer 102a and the semiconductor layer 102b may be in-situ doped or doped by an ion implantation process, but the present disclosure is not limited thereto. For example, in some embodiments, the semiconductor layer 102a may be made of n-type GaN doped with dopants such as silicon or oxygen, and the semiconductor layer 102b may be made of p-type GaN doped with dopants such as magnesium, but the present disclosure is not limited thereto.
In some embodiments, the semiconductor layer 102a, the semiconductor layer 102b, and the light-emitting portion 102e may be patterned by an applicable patterning process. For example, the patterning process may include a lithography process, an etching process, other applicable processes, or a combination thereof. In some embodiments, the lithography process may include resist coating, soft baking, exposure, post-exposure baking, developing, other applicable processes, or a combination thereof, but the present disclosure is not limited thereto. In some embodiments, the etching process may include a wet etching process, a dry etching process, other applicable processes, or a combination thereof, but the present disclosure is not limited thereto.
In some embodiments, the conductive pad 102c and the conductive pad 102d may be respectively made of a metal, other applicable conductive materials, or a combination thereof, but the present disclosure is not limited thereto. For example, the metal may include Cu, W, Ag, Sn, Ni, Cr, Ti, Pb, Au, Bi, Sb, Zn, Zr, Mg, In, Te, Ga, other applicable metals, alloys thereof, or a combination thereof. In some embodiments, the conductive pad 102c and the conductive pad 102d may be respectively made of a transparent conductive material. For example, the transparent conductive material may include ITO, SnO, IZO, IGZO, ITZO, ATO, AZO, other applicable transparent conductive materials, or a combination thereof, but the present disclosure is not limited thereto.
In some embodiments, a blanket layer (not shown in the figures) of a metal or a transparent conductive material may be formed on the semiconductor layer 102a and the semiconductor layer 102b by a physical vapor deposition process (e.g., evaporation process or sputtering process), an electro-plating process, an atomic layer deposition process, other applicable processes, or a combination thereof, and then a patterning process such as a lithography process and an etching process may be used to pattern the blanket layer of the metal or transparent conductive material to form the conductive pad 102c and the conductive pad 102d. In some embodiments, the conductive pad 102c and the conductive pad 102d may be the electrodes of the light-emitting diode 102, and may be used to provide an electrical connection with the substrate 100 of the display device 10. For example, one of the conductive pad 102c and the conductive pad 102d may be the p-type electrode of the light-emitting diode 102, and the other of the conductive pad 102c and the conductive pad 102d may be the n-type electrode of the light-emitting diode 102. In some embodiments, the conductive pad 102c is in direct contact with the semiconductor layer 102b, and the conductive pad 102d is in direct contact with the semiconductor layer 102a.
It should be understood that the elements and/or the forming methods of the light-emitting diode 104 and the light-emitting diode 106 may be the same as or similar to those of the light-emitting diode 102. Furthermore, the light-emitting diode 104 and the light-emitting diode 106 may respectively include a semiconductor layer 104a and a semiconductor layer 106a the same as or similar to the semiconductor layer 102a, the light-emitting diode 104 and the light-emitting diode 106 may both include another semiconductor layer (not shown in the figures) the same as or similar to the semiconductor layer 102b, the light-emitting diode 104 and the light-emitting diode 106 may respectively include a light-emitting portion 104e and a light-emitting portion 106e the same as or similar to the light-emitting portion 102e, the light-emitting diode 104 and the light-emitting diode 106 may respectively include a conductive pad 104c and a conductive pad 106c the same as or similar to the conductive pad 102c, and the light-emitting diode 104 and the light-emitting diode 106 may respectively include a conductive pad 104d and a conductive pad 106d the same as or similar to the conductive pad 102d. In some embodiments, the dimensions, the shapes, and/or the sizes of these light-emitting diodes may be substantially the same as each other according to the design requirements, but the present disclosure is not limited thereto. In some other embodiments, the dimensions, the shapes, and/or the sizes of these light-emitting diodes may be different from each other according to the design requirements.
In some embodiments, as shown in
In some embodiments, as shown in
For example, in some embodiments, the ratio of the distance D1 to the distance D2 may be greater than zero and less than one (e.g., 0<(D1/D2)<1), and the ratio of the distance D3 to the distance D4 may be greater than zero and less than one (e.g., 0<(D3/D4)<1).
In some embodiments, the light-emitting diodes corresponding to a pixel of the display device 10 may be arranged in a triangle. For example, as shown in
In some embodiments, the light-emitting portions and the conductive pads corresponding to the light-emitting portions of the light-emitting diodes of a pixel of the display device 10 are disposed toward the interior of the pixel, and the conductive pads not corresponding to the light-emitting portions are disposed in the periphery of the pixel, and thus the contrast ratio of the display device 10 may be increased. For example, as shown in
In some embodiments, two light-emitting diodes in a pixel (e.g., pixels P1, P2, P3, P4, P5, P6, P7, and P8) of the display device 10 may have an included angle therebetween. For example, the included angel may be defined as the angle between the central connecting line (which extends in one direction) of two adjacent conductive pads (e.g., conductive pad 102c and conductive pad 102d) of one light-emitting diode (e.g., the light-emitting diode 102) and the central connecting line (which extends in another direction) of two adjacent conductive pads (e.g., conductive pad 104c and conductive pad 104d) of another light-emitting diode (e.g., the light-emitting diode 104). In some embodiments, as shown in
In some embodiments, the light-emitting diode 102, the light-emitting diode 104, and the light-emitting diode 106 may be the same color (i.e., the emitting light of the light-emitting diode 102, the emitting light of the light-emitting diode 104, and the emitting light of the light-emitting diode 106 are the same color), and therefore a wavelength conversion layer (not shown in the figures) may be disposed on the substrate 100 of the display device 10 so that the display device 10 can emit white light. For example, the light-emitting diode 102, the light-emitting diode 104, and the light-emitting diode 106 may be blue light-emitting diodes, but the present disclosure is not limited thereto. In some embodiments, “two light-emitting diodes being the same color” means the absolute value of the difference between the wavelength corresponding to the maximum peak of the output spectrum of one light-emitting diode (e.g., light-emitting diode 102) and the wavelength corresponding to the maximum peak of the output spectrum of another light-emitting diode (e.g., light-emitting diode 104) is smaller than or equal to 2 nm. On the other hand, in some embodiments, “two light-emitting diodes being different colors” means the absolute value of the difference between the wavelength corresponding to the maximum peak of the output spectrum of one light-emitting diode (e.g., light-emitting diode 102) and the wavelength corresponding to the maximum peak of the output spectrum of another light-emitting diode (e.g., light-emitting diode 104) is larger than 2 nm.
In some embodiments, the light-emitting diode 102, the light-emitting diode 104, and the light-emitting diode 106 may be different colors (i.e., the emitting light of the light-emitting diode 102, the emitting light of the light-emitting diode 104, and the emitting light of the light-emitting diode 106 are different colors). For example, in some embodiments, the light-emitting diode 102 of the display device 10 is a blue light-emitting diode, the light-emitting diode 104 of the display device 10 is a red light-emitting diode, and the light-emitting diode 106 of the display device 10 is a green light-emitting diode, but the present disclosure is not limited thereto.
As shown in
In some embodiments, as shown in
In some embodiments, a bonding pad group may include at least one bonding pad. For example, as shown in
In some embodiments, the bonding pad 100a may correspond to the conductive pad 102c corresponding to the light-emitting portion 102e of the light-emitting diode 102, the bonding pad 100a′ may correspond to the conductive pad 102d not corresponding to the light-emitting portion 102e of the light-emitting diode 102, the bonding pad 100b may correspond to the conductive pad 104c corresponding to the light-emitting portion 104e of the light-emitting diode 104, the bonding pad 100b′ may correspond to the conductive pad 104d not corresponding to the light-emitting portion 104e of the light-emitting diode 104, the bonding pad 100c may correspond to the conductive pad 106c corresponding to the light-emitting portion 106e of the light-emitting diode 106, the bonding pad 100c′ may correspond to the conductive pad 106d not corresponding to the light-emitting portion 106e of the light-emitting diode 106. In other words, in these embodiments, the bonding pad 100a may be bonded to and electrically connected to the conductive pad 102c, the bonding pad 100a′ may be bonded to and electrically connected to the conductive pad 102d, the bonding pad 100b may be bonded to and electrically connected to the conductive pad 104c, the bonding pad 100b′ may be bonded to and electrically connected to the conductive pad 104d, the bonding pad 100c may be bonded to and electrically connected to the conductive pad 106c, the bonding pad 100c′ may be bonded to and electrically connected to the conductive pad 106d. In some embodiments, from a top view of the substrate, the shapes of the bonding pads may be designed to be the same as or different from the shapes of their own corresponding conductive pads of the light-emitting diodes. For example, the shapes of the bonding pads may be round or polygon, but the present disclosure is not limited thereto. In some embodiments, the bonding pads may be designed to be any other applicable shape according to the design requirements.
In some embodiments, a flip chip bonding process may be used to bond the light-emitting diode 102, the light-emitting diode 104, and the light-emitting diode 106 onto the substrate 100 through the bonding pad group 100A, the bonding pad group 100B, and the bonding pad group pad 100C.
It should be understood that although the above paragraphs are discussed by using an example in which a pixel (e.g., pixels P1, P2, P3, P4, P5, P6, P7, and P8) of the display device 10 corresponds to or includes three bonding pad groups (i.e., the boding pad group 100A, the bonding pad group 100B, and the bonding pad group 100C), the present disclosure is not limited thereto. In some other embodiments, a pixel of the display device may correspond to or include any other applicable number of bonding pad groups according to the design requirements (e.g., according to the number of light-emitting diodes which a pixel corresponds to or includes).
In some embodiments, the bonding pad group 100A, the bonding pad group 100B, and the bonding pad group 100C may be made of a metal, other applicable conductive materials, or a combination thereof, but the present disclosure is not limited thereto. For example, the metal may include Cu, W, Ag, Sn, Ni, Cr, Ti, Pb, Au, Bi, Sb, Zn, Zr, Mg, In, Te, Ga, other applicable metals, alloys thereof, or a combination thereof.
For example, the substrate 100 may include a driving circuit (not shown in the figures), and the driving circuit may be electrically connected to the light-emitting diode 102, the light-emitting diode 104, and the light-emitting diode 106, so as to control and/or adjust the brightness of these light-emitting diodes. In some embodiments, the substrate 100 may be a thin-film transistor (TFT) array substrate, but the present disclosure is not limited thereto.
It should be understood that although they are not shown in the figures, the display device 10 may also include some other elements (e.g., a cover plate or an optical film). For example, the cover plate may be made of glass, indium tin oxide, polyimide, polyethylene terephthalate, other applicable materials, or a combination thereof, but the present disclosure is not limited thereto. For example, the optical film may include a diffuser film, a condenser lens, other applicable optical films, or a combination thereof, but the present disclosure is not limited thereto.
In some embodiments, the pixels of the display device 10 may be staggered to each other, and thus the resolution of the display device 10 may be increased. For example, in some embodiments, as shown in
In summary, in the display device of the present embodiment, the distance between conductive pads corresponding to the light-emitting portions of two adjacent light-emitting diodes is less than the distance between the conductive pads not corresponding to the light-emitting portions of the two adjacent light-emitting diodes, thereby increasing the contrast ratio of the display device. In addition, in some embodiments, the pixels of the display device may be staggered to each other, and thus the resolution of the display device may be increased.
One difference between Embodiment 1 and Embodiment 2 is that two adjacent pixels of the display device 30 of Embodiment 2 may share or jointly correspond to at least one light-emitting diode, so that the display device 30 may have higher resolution.
It should be noted that, unless otherwise specified, the elements of Embodiment 2 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
As shown in
In some embodiments, as shown in
It should be understood that although the above paragraphs are discussed by using an example in which the light-emitting diode 302 has two separated light-emitting portions 302e, the present disclosure is not limited thereto. For example, in some other embodiments, the light-emitting diode 302 may have more separated light-emitting portions 302e (e.g., more than two light-emitting portions 302e) according to design requirements, and the number of semiconductor layers 302b and the number of conductive pads 302c may be increased accordingly.
In some embodiments, since the light-emitting diode 302 has a plurality of separated light-emitting portions 302e, two adjacent pixels of the display device 30 may share or jointly correspond to at least one light-emitting diode 302, increasing the resolution of the display device 30. In addition, in some embodiments, the plurality of separated light-emitting portions 302e of the light-emitting diode 302 may share one conductive pad 302d, and thus the resolution of the display device 30 may be further increased.
One difference between Embodiment 1 and Embodiment 3 is that the light-emitting diode of the display device 40 of Embodiment 3 has a plurality of separated light-emitting portions, and thus the manufacturing cost of the display device 40 may be lower.
It should be noted that, unless otherwise specified, the elements of Embodiment 3 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
As shown in
In some embodiments, the light-emitting diodes 402 which a pixel of the display device 40 corresponds to may be the same color, but the present disclosure is not limited thereto. In some other embodiments, the light-emitting diodes 402 which a pixel of the display device 40 corresponds to may be different colors.
In some embodiments, as shown in
It should be understood that although the above paragraphs are discussed by using an example in which the light-emitting diode 402 has two separated light-emitting portions 402e, the present disclosure is not limited thereto. For example, in some other embodiments, the light-emitting diode 402 may have more separated light-emitting portions 402e (e.g., more than two light-emitting portions 402e) according to design requirements, and the number of semiconductor layers 402b and the number of conductive pads 402c may be increased accordingly.
In some embodiments, since the light-emitting diode 402 has a plurality of separated light-emitting portions 402e, if one of the light-emitting portions 402e cannot emit the light normally (e.g., due to abnormal quality), the emitting light of any other light-emitting portion 402e may still be used to maintain the display function of the display device 40, and thus the yield of the display device 40 may be improved and the manufacturing cost may be reduced.
One difference between Embodiment 4 and Embodiment 1 is that the substrate 500 of the display device 50 of Embodiment 4 includes redundant bonding pad groups, so that the manufacturing process of the display device 50 may have a greater flexibility.
It should be noted that, unless otherwise specified, the elements of Embodiment 4 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
In some embodiments, the light-emitting diodes 102 which a pixel of the display device 50 corresponds to may be the same color, but the present disclosure is not limited thereto. In some other embodiments, the light-emitting diodes 102 which a pixel of the display device 50 corresponds to may be different colors.
Similar to the display device 10 of Embodiment 1, the substrate 500 of the display device 50 may include a plurality of bonding pad groups 100A, and the light-emitting diodes 102 may be bonded to and electrically connected to the substrate 500 through the bonding pad groups 100A. As shown in
In some embodiments, some light-emitting diodes 102 may be bonded to the substrate 500 through the bonding pad groups 100A, and then a quality test may be performed to test the qualities of these light-emitting diodes 102, if the qualities of these light-emitting diodes are abnormal (e.g., being unable to emit the light normally), other light-emitting diodes 102 may be bonded to the substrate 500 through the redundant bonding pad groups 500A, such that the display device 50 may still have normal display function. In other words, in these embodiments, since the substrate 500 includes the redundant bonding pad groups 500A, the manufacturing process of the display device 50 may have a greater flexibility and lower cost. Furthermore, similar to the display device 10 of Embodiment 1, in some embodiments, the light-emitting portions 102e and the conductive pads 102c corresponding to the light-emitting portions 102e of the light-emitting diodes 102 which a pixel of the display device 50 corresponds to may be disposed toward the interior of the pixel, and the conductive pads 102d not corresponding to the light-emitting portions 102e of the pixel may be disposed in the periphery of the pixel. Therefore, in these embodiments, in a pixel of the display device 50, the light-emitting locations of the light-emitting diodes 102 bonded to the substrate 500 through the bonding pad groups 100A may be close to the light-emitting locations of the light-emitting diodes 102 bonded to the substrate 500 through the redundant bonding pad groups 500A. Thus, when the emitting lights of the light-emitting diodes 102 bonded to the substrate 500 through the bonding pad groups 100A are replaced with the emitting lights of the light-emitting diodes 102 bonded to the substrate 500 through the redundant bonding pad groups 500A, the visual effect may still be maintained as expected.
In some embodiments, after the quality test discussed above, the qualities of the light-emitting diodes 102 bonded to the substrate 500 through the bonding pad groups 100A are normal (e.g., able to emit the lights normally), so it may not be necessary to bond other light-emitting diodes 102 onto the substrate 500 through the redundant bonding pad groups 500A. Therefore, in these embodiments, the redundant bonding pad groups 500A of the final display device 50 may not be bonded with any light-emitting diodes 102.
In some embodiments, as shown in
In some embodiments, in a pixel of the display device 50, the number of bonding pad groups 100A may be the same as the number of redundant bonding pad groups 500A. For example, as shown in
It should be understood that although the above paragraphs are discussed by using an example in which a pixel (e.g., pixels P1, P2, P3, P4, P5, P6, P7, and P8) of the display device 50 corresponds to or includes three bonding pad groups 100A and three redundant bonding pad groups 500A, the present disclosure is not limited thereto. In some other embodiments, a pixel of the display device 50 may correspond to or include any other applicable number of the bonding pad groups 100A and the redundant bonding pad groups 500A according to design requirements. It should be understood that the materials, functions of the bonding pads 500a and 500a′ of the redundant bonding pad group 500A, and/or their corresponding relationships with the light-emitting diode 102 may be the same as or similar to those of the bonding pads 100a and 100a′ of the bonding pad group 100A. For simplicity and clarity, the details will not be repeated.
The light-emitting diodes of Embodiment 5 have high strength, so it may reduce the occurrence of cracks in the manufacturing process (e.g., a laser lift-off process) and reduce the manufacturing cost. Details of Embodiment 5 will be discussed in the following paragraphs.
It should be noted that, unless otherwise specified, the elements of Embodiment 5 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
First, as shown in
As shown in
For example, the semiconductor layer 602a may be the same as or similar to the semiconductor layer 102a, the semiconductor layers 602b may be the same as or similar to the semiconductor layer 102b, the light-emitting portions 602e may be the same as or similar to the light-emitting portion 102e, the conductive pads 602c may be the same as or similar to the conductive pad 102c, and the conductive pad 602d may be the same as or similar to the conductive pad 102d. In other words, the materials, functions, and/or forming methods of the elements of the light-emitting diode 602 may be the same as or similar to those of the light-emitting diode 102 of the above embodiments. For simplicity and clarity, the details will not be repeated.
Furthermore, in some embodiments, the conductive pad 602c and the conductive pad 602d may be made of a metal (e.g., Cu, W, Ag, Sn, Ni, Cr, Ti, Pb, Au, Bi, Sb, Zn, Zr, Mg, In, Te, Ga, other applicable metals, alloys thereof, or a combination thereof).
As shown in
In some embodiments, the distance (minimum distance) between at least one of the conductive pads 602c and 602d, and at least one of the sides (e.g., sides S1, S2, S3, and S4) of the semiconductor layer 602a may be less than or equal to 25 μm (e.g., in a range between 0.5 μm and 25 μm), and thus the edge strength of the light-emitting diode 602 may be increased, reducing the occurrence of cracks in the manufacturing process. For example, as shown in FIG. 6B, the distance (minimum distance) T1 between the conductive pad 602d and the side S1 of the semiconductor layer 602a may be less than or equal to 25 μm (e.g., 0.5 μm≤T1≤25 μm).
Furthermore, in some embodiments, the distances (minimum distances) between at least one of the conductive pads 602c and 602d of the light-emitting diode 602, and all the adjacent sides of the semiconductor layer 602 may be less than or equal to 25 μm (e.g., in a range between 0.5 μm and 25 μm), and thus the edge strength of the light-emitting diode 602 may be further increased, further reducing the occurrence of cracks in the manufacturing process and reducing the manufacturing cost. For example, in some embodiments, as shown in
In some embodiments, the conductive pad 602c and the conductive pad 602d are made of the metals discussed above, these metals have high strength, and thus the edge strength of the light-emitting diode 602 may be further increased.
In some embodiments, the distance (e.g., minimum distance) between two adjacent conductive pads of the light-emitting diode 602 may be less than or equal to 30 μm (e.g., in a range between 2 μm and 30 μm), and thus the strength for supporting the light-emitting diode 602 may be increased. For example, as shown in
In some embodiments, in a top view, the ratio of the sum of the areas of all conductive pads (e.g., the conductive pad 602c and the conductive pad 602d) of the light-emitting diode 602 to the area of the semiconductor layer 602a of the light-emitting diode 602 may be greater than or equal to 50% (e.g., greater than or equal to 50%, and less than or equal to 90%), and thus the strength of the light-emitting diode 602 may be increased.
It should be understood that although the above paragraphs are discussed by using an example in which two conductive pads (i.e., conductive pad 602c and conductive pad 602d) are disposed on the surface 602t of the semiconductor layer 602a of the light-emitting diode 602, the present disclosure is not limited thereto. For example, any applicable number of conductive pads (e.g., one, or more than two) may be disposed on the surface 602t of the semiconductor layer 602a of the light-emitting diode 602 according to the design requirements. For example, in some embodiments, the light-emitting diode 602 may be a vertical-type light-emitting diode, and thus there may be only one conductive pad disposed on the surface 602t of the semiconductor layer 602a, and there may be another conductive pad disposed on another surface of the semiconductor layer 602a opposite to the surface 602t.
In some embodiments, the conductive pad of the light-emitting diode 602 may have at least one round corner, which may further reduce the occurrence of cracks of the light-emitting diode 602 in the manufacturing process (e.g., a laser lift-off process). For example, in some embodiments, as shown in
In some embodiments, the semiconductor layer 602a of the light-emitting diode 602 may have at least one round corner, which may further reduce the occurrence of cracks of the light-emitting diode 602 in the manufacturing process (e.g., a laser lift-off process). For example, in some embodiments, as shown in
In some embodiments, a curvature of the round corner C1 of the conductive pad (602d or 602c) may be different from a curvature of the round corner C2 of the semiconductor layer 602a, which may more effectively reduce the occurrence of cracks of the light-emitting diode 602 in the manufacturing process.
In some embodiments, the conductive pad of the light-emitting diode 602 may have at least one curved portion (e.g., a curved side), which may further reduce the occurrence of cracks of the light-emitting diode 602 in the manufacturing process (e.g., a laser lift-off process). For example, in some embodiments, as shown in
In some embodiments, a radius of curvature of the curved portion Z1 of the conductive pad (602d or 602c) may be different from a radius of curvature of the round corner Z2 of the semiconductor layer 602a, which may more effectively reduce the occurrence of cracks of the light-emitting diode 602 in the manufacturing process.
In Embodiment 6, the light-emitting diodes of the display device are bonded onto the substrate through a conductive adhesive layer, the conductive adhesive layer includes conductive materials, the conductive materials may be made of a metal having low melting point or an alloy having low eutectic point, and thus the reliability of the display device may be increased and the manufacturing cost may be reduced. The details will be discussed below.
It should be noted that, unless otherwise specified, the elements of Embodiment 6 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
First, as shown in
Still referring to
In some embodiments, the conductive materials 704b may be made of a metal having low melting point. For example, the metal having low melting point may include In, Ga, Sn, other applicable metals, or a combination thereof. In some embodiments, the metal having low melting point may include, for example, nano-metal powders (e.g., nano-silver powders, nano-copper powders, nano-gold powders, other applicable nano-metal powders, or a combination thereof), but the present disclosure is not limited thereto. In some embodiments, the conductive materials 704b may be made of a metal alloy having low eutectic point. For example, the metal alloy having low eutectic point may include In—Ag alloy, In—Sn alloy, Ag—Sn alloy, Sn—Zn alloy, Sn—Bi alloy, Sn—Au alloy, Sn—Ag—Cu alloy, In—Ag—Sn alloy, other applicable metal alloys, or a combination thereof.
In some embodiments of which the conductive materials 704b are made of a metal alloy having low eutectic point, the properties (e.g., the melting point, the hardness, and/or the toughness) of the conductive materials 704b may be adjusted by adjusting the composition ratios of the metals of the metal alloy, and thus the flexibility of the manufacturing process may be increased.
In some embodiments, the non-conductive adhesive material 704a may be a light curing material, a thermal curing material, other applicable materials, or a combination thereof. For example, the non-conductive adhesive material 704a may include gels (or glues) made of polymers (e.g., acrylic, epoxy, other applicable polymers, or a combination thereof), but the present disclosure is not limited thereto.
Still referring to
Then, as shown in
In some embodiments, the attaching process may include heating the non-conductive adhesive material 704a to an applicable temperature (e.g., in a range between 100° C. to 250° C.) to increase the flowability of the non-conductive adhesive material 704a. In some embodiments, the attaching process may include using the pick-up head 708 to apply an applicable pressure toward the substrate 700, such that the conductive materials 704b disposed between the conductive pad 706c (or 706d) and the bonding pad 702 may be slightly deformed. Then, in some embodiments, the pick-up head 708 is removed.
Then, as shown in
In some embodiments, the non-conductive adhesive material 704a is a thermal curing material, and the curing temperature of the non-conductive adhesive material 704a is greater than the process temperature of the bonding process. Therefore, in these embodiments, after the light-emitting diode 706 is bonded to the substrate 700 by the bonding process, the non-conductive adhesive material 704a has not been cured yet, increasing the feasibility of rework. In other words, in these embodiments, after the bonding process, a quality test may be performed to test the qualities of the light-emitting diodes 706 bonded to the substrate 700, since the non-conductive adhesive material 704a has not been cured yet, the light-emitting diodes 706 which are tested to be abnormal in quality may still be removed from the substrate 700 and be replaced with other light-emitting diodes 706 before the curing process (e.g., heating the non-conductive adhesive material 704a to a temperature higher than or equal to the curing temperature of the non-conductive adhesive material 704a) is performed to cure the non-conductive adhesive material 704a.
In some embodiments, the non-conductive adhesive material 704a is a thermal curing material, and the curing temperature of the non-conductive adhesive material 704a is less than or equal to the process temperature of the bonding process. In other words, in these embodiments, the non-conductive adhesive material 704a is cured in the bonding process, reducing the occurrence of short circuit resulting from the connection between the conductive materials 704b in the bonding process.
In some embodiments, the non-conductive adhesive material 704a is a light curing material (e.g., UV light curing material). In these embodiments, the curing process for curing the non-conductive adhesive material 704a may not substantially affect the conductive materials 704b. In some embodiments of which the non-conductive adhesive material 704a is a light curing material, the curing process for curing the non-conductive adhesive material 704a may be performed after the bonding process, increasing the feasibility of rework. In some embodiments, when the non-conductive adhesive material 704a is a light curing material, the curing process for curing the non-conductive adhesive material 704a may be performed before the bonding process, reducing the occurrence of short circuit.
In some embodiments, as shown in
In the embodiments illustrated in
One difference between Embodiment 7 and Embodiment 6 is that the conductive materials of the conductive adhesive layer of Embodiment 7 are disposed corresponding to the bonding pads of the substrate and/or the conductive pads of the light-emitting diodes, and thus the occurrence of short-circuit may be reduced.
It should be noted that, unless otherwise specified, the elements of Embodiment 7 the same as or similar to those of the above embodiments will be denoted by the same reference numerals, and the forming methods thereof may be the same as or similar to those of the above embodiments.
First, as shown in
Still referring to
In some embodiments, as shown in
In some embodiments, since the conductive materials 904b are disposed on and corresponding to the bonding pads 902, there is no conductive materials between adjacent bonding pads 902, reducing the occurrence of short circuit.
For example, a conductive blanket layer (not shown in the figures) may be formed on the substrate 900 by a physical vapor deposition process (e.g., evaporation process or sputtering process), an electroplating process, an atomic layer deposition process, other applicable processes, or a combination thereof, and then a patterning process such as a lithography process and an etching process may be used to pattern the conductive blanket layer to form the conductive materials 904b on the bonding pads 902 of the substrate 900, and then a process such as a spin-on coating process may be used to form the non-conductive adhesive material 904a on the substrate 900 and the conductive materials 904b, such that the conductive adhesive layer 904 including the non-conductive adhesive material 904a and the conductive materials 904b is formed on the substrate 900.
Then, as shown in
In some embodiments, since the conducive materials 904b are disposed on and corresponding to the bonding pads 902, and the conductive pad 906c and the conductive pad 906d of the light-emitting diode 906 are also disposed on and corresponding to the conductive materials 904b, there is no conductive materials 904b between the conductive pad 906c and the conductive pad 906d adjacent to the conductive pad 906c of the light-emitting diode 906, and the occurrence of shot circuit may be reduced. In some other embodiments, there is at least one conductive material 904b between the conductive pad 906c and the conductive pad 906d adjacent to the conductive pad 906c of the light-emitting diode 906, but the at least one conductive material 904b is electrically floated with respect to the conductive pads 906c and 906d on the left side and right side of the at least one conductive material 904b, and thus the occurrence of short circuits may be avoided.
For example, the main portion 906m of the light-emitting diode 906 may be the same as or similar to the main portion 706m of the light-emitting diode 706 of the above embodiments, the conducive pads 906c and 906d of the light-emitting diode 906 may be the same as or similar to the conductive pads 706c and 706d of the light-emitting diode 706. In some embodiments, since the conductive materials 904b are also made of a metal having low melting point or a metal alloy having low eutectic point, the present embodiment also has the advantages (e.g., low manufacturing cost) the same as or similar to those of the above embodiments.
It should be understood that although the conductive adhesive layer 904 is formed on the substrate 900, and then the light-emitting diodes 906 are bonded to the substrate 900 through the conductive materials 904b in the embodiment discussed above, the present disclosure is not limited thereto. In some other embodiments, the light-emitting diodes 906 may be disposed on a substrate (not shown in the figures), and then the conductive materials 904b are disposed on and corresponding to the conductive pads 906c and the conductive pads 906d of the light-emitting diodes 906, and then the non-conductive adhesive material 904a is disposed on the substrate, the conductive pads 906c, the conductive pads 906d, and the conductive materials 904b corresponding to the conductive pads 906c and the conductive pads 906d, and then a bonding process may be performed to bond the light-emitting diodes 906 onto the substrate 900 through the conductive materials 904b, and a curing process may be performed to cure the non-conductive adhesive material 904a to form the display device 90.
First, as shown in
For example, the temporary substrate 1000 may be made of polyimide, but the present disclosure is not limited thereto. For example, the openings 1002 may be formed in the temporary substrate 1000 by a lithography process, an etching process, a mechanical drilling process, a laser drilling process, other applicable processes, or a combination thereof, but the present disclosure is not limited thereto.
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Then, as shown in
Still referring to
In summary, the conductive materials of the conductive adhesive layer of the present embodiment are disposed corresponding to the bonding pads of the substrate of the display device and/or the conductive pads of the light-emitting diodes, and thus the occurrence of short circuits may be reduced.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure. In addition, each claim can be an individual embodiment of the present disclosure, and the scope of the present disclosure includes the combinations of every claim and every embodiment of the present disclosure.
Number | Date | Country | Kind |
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201810342285.5 | Apr 2018 | CN | national |
This application claims priority of provisional application of U.S. Patent Application No. 62/561,220 filed on Sep. 21, 2017, provisional application of U.S. Patent Application No. 62/608,004 filed on Dec. 20, 2017, and China Patent Application No. 201810342285.5 filed on Apr. 17, 2018, the entirety of which are incorporated by reference herein.
Number | Date | Country | |
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62608004 | Dec 2017 | US | |
62561220 | Sep 2017 | US |