Patent Application
20180019418
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-140364, filed Jul. 15, 2016, the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a display device.
There has been a demand of narrowing the frame in display devices comprising organic electroluminescence (EL) elements or liquid crystal display devices. Under these circumstances, display devices which employ a flexible substrate are being developed. In such display devices, the frame area is reduced by bending the flexible substrate.
The manufacture of such a display device requires a processing step of peeling a flexible substrate off from, for example a support substrate such as a glass substrate. Here, if a foreign matter or the like is attached to the support substrate and a laser beam for peeling-off is irradiated towards the support substrate, laser beam may be absorbed into the foreign matter, thereby causing a peeling error. Moreover, if the foreign matter is firmly stuck onto the support substrate, washing carried out before the irradiating of the laser beam cannot remove the foreign matter only by itself.
In general, according to one embodiment, a display device includes an insulating substrate on which a display function layer is provided, and a protection member attached onto the insulating substrate, and the insulating substrate further includes a first surface on which the display function layer is formed and a second surface on an opposite side to the first surface, on which the protection member is attached, and at least one of the first surface and the second surface includes a projection and a recess.
According to another embodiment, a method of manufacturing a display device includes forming an insulating substrate on a glass substrate comprising a projection and a recess, forming an array layer containing a switching element on the insulating substrate, forming a display function layer on the array layer, irradiating a laser beam onto a surface of the glass substrate, on which the insulating substrate is not formed, and peeling the insulating substrate off from the glass substrate.
Embodiments will be described hereinafter with reference to the accompanying drawings. Incidentally, the disclosure is merely an example, and proper changes within the spirit of the invention, which are easily conceivable by a skilled person, are included in the scope of the invention as a matter of course. In addition, in some cases, in order to make the description clearer, the widths, thicknesses, shapes, etc. of the respective parts are schematically illustrated in the drawings, compared to the actual modes. However, the schematic illustration is merely an example, and adds no restrictions to the interpretation of the invention. Besides, in the specification and drawings, the structural elements having functions, which are identical or similar to the functions of the structural elements described in connection with preceding drawings, are denoted by like reference numerals, and an overlapping detailed description is omitted unless otherwise necessary.
In this embodiment, the positive direction of the third direction Z is defined as up or above, and the negative direction of the third direction Z is defined as down or below. Further, such expressions as “the second member above the first member” and “the second member below the first member”, the second member may be in contact with the first member or may be separated from the first member. In the case of the latter, the third member may be interposed between the first member and the second member.
The display device 1 comprises a display panel 2, a first circuit substrate 3, a second circuit substrate 4 and the like. The display panel 2 comprises a first substrate SUB1 and a second substrate SUB2 disposed to oppose the first substrate SUB1.
The display panel 2 includes a display area DA, a peripheral area SA surrounding the display area DA and a mounting portion MT. The display area DA is an area where images are displayed, and comprises a plurality of pixels PX arrayed in, for example, a matrix. The pixels PX each include a light-emitting device, which will be described later and a switching element which drives the light-emitting device, etc.
The mounting portion MT is provided on one end side of the display panel 2 in the second direction Y. That is, the first substrate SUB1 includes a portion extending out from the region overlapping the second substrate SUB2. More specifically, three side edges of the first substrate SUB1 are aligned with respective three side edges of the second substrate SUB2 in the third direction Z. Each side edge of the first substrate SUB1, which is parallel to the first direction X and a respective side edge of the second substrate SUB2, which is parallel to the first direction X have a substantially same length. Each side edge of the first substrate SUB1, parallel to the second direction Y is longer than a respective side edge of the second substrate SUB2, parallel to the second direction Y. That is, an area of the first substrate SUB1, parallel to an X-Y plane is larger than an area of the second substrate SUB2, parallel to the X-Y plane. Here, the X-Y plane is a plane defined by the first direction X and the second direction Y. In this embodiment, the side edges of substrate SUB2, parallel to the second direction Y may be substantially equal in length to the respective side edges of the first substrate SUB1, parallel to the second direction Y. In this case, the area of the second substrate SUB2, parallel to the X-Y plane is substantially the same as the area of first substrate SUB1, parallel to the X-Y plane.
The first circuit substrate 3 and the second circuit substrate 4 are provided on one end side of the display panel 2 in the second direction Y.
The first circuit substrate 3 is provided between the display panel 2 and the second circuit substrate 4. The first circuit substrate 3 is a flexible printed circuit substrate, for example. In the example illustrated, the first circuit substrate 3 is mounted above the mounting portion MT. The display panel 2 and the first circuit substrate 3 are electrically connected to each other. The first circuit substrate 3 comprises a drive IC chip 5 which drives the display panel 2, etc. In the example illustrated, the driving IC chip 5 is mounted above the first circuit substrate 3, but may be below the circuit substrate 3. In the example illustrated, the length of side edges of the first circuit substrate 3, parallel to the first direction X is less than the length of the respective side edges of the first substrate SUB1 and second substrate SUB2, parallel to the first direction X, but they may be substantially equal respectively to each other.
The second circuit substrate 4 is a flexible printed circuit substrate, for example. The second circuit substrate 4 is connected to the first circuit substrate 3, for example, under the first circuit substrate 3.
Here, in this embodiment, the display device 1 includes a bending area BA, which is a region bent when accommodated in a housing such as of an electronic device. The bending area BA is hatched in the figure. The bending area BA is bent so as to place the first circuit substrate 3 and the second circuit substrate 4 below the display area DA.
A protection member PP is attached to below the display panel 2. The protection member PP is not placed at a position overlapping the bending area BA in the third direction Z.
As shown in
The first insulating substrate 10 is formed of, for example, an organic insulating material such as polyimide. The first insulating substrate 10 comprises a first surface 10A and second surface 10B, which is a surface on an opposite side to the first surface 10A. The organic EL device OD is formed on a first surface 10A side. The protection member PP is formed on a second surface 10B side with an adhesive member GL. The protection member PP is a protection film which protects the first insulating substrate 10 and is formed of, for example, polyethylene terephthalate (PET). The protection member PP comprises a third surface PA attached onto the second surface 10B. For example, a thickness TPP of the protection member PP is greater than a thickness T10 of the first insulating substrate 10.
In this embodiment, at least one of the first surface 10A and the second surface 10B is a rough surface with projections and recesses. The rough surface will be described in detail later, but the grade of a rough surface can be defined by, for example, the surface coarseness. In the example shown in
The adhesive member GL is in contact with the third surface PA, which is more even than the second surface 10B and the second surface 10B. Thus, the adhesive member GL includes a region in the X-Y plane, whose thickness differs from one location to another. More specifically, a thickness T1 of the adhesive member GL in contact with the recesses of the second surface 10B is greater than a thickness T2 of the adhesive member GL in contact with the projections adjacent respectively to the projections.
On the first surface 10A of the first insulating substrate 10, a first insulating film 11 is formed as an overcoat layer. The first insulating film 11 is in contact with the first surface 10A. The first insulating film 11 may be omitted. Moreover, the first insulating film 11 may contain a barrier layer to suppress the entering of moisture or the like, from the first insulating substrate 10 towards the organic EL device OD.
The switching elements SW are formed on the first insulating film 11. The switching elements SW are each a thin film transistor (TFT), for example. The switching elements each comprise a semiconductor layer SC, a gate electrode GE, a source electrode SE and a drain electrode DE. The semiconductor layer SC is formed on the first insulating film 11 and is covered by a second insulating film 12. The gate electrode GE is formed on the second insulating film 12 and is covered by a third insulating film 13. The source electrode SE and the drain electrode DE are both formed on the third insulating film 13 and are in contact with semiconductor layer SC. The first to third insulating films 11 to 13 are each formed from an inorganic insulating material such as silicon oxide, silicon nitride or silicon oxynitride. In this embodiment, the first insulating film 11 is equivalent to an inorganic insulating layer. In the example illustrated, the switching element SW is of a top-gate type, but it may be of a bottom-gate type.
The switching element SW is covered by a fourth insulating film 14. The fourth insulating film 14 is formed from an organic insulating material.
The organic EL device OD is formed on the fourth insulating film 14. In the example illustrated, the organic EL device OD is of the so-called top-emission type, which emits light to an opposite side to the first insulating substrate 10, but may be of the so-called bottom-emission type, which emits light to a first insulating substrate 10 side. The organic EL device OD comprises a pixel electrode PE, a common electrode CE and an organic light-emitting layer ORG between the pixel electrode PE and the common electrode CE.
The organic EL device OD is partitioned into each pixel PX with a rib 15 formed from an organic insulating material. That is, in a region where the rib 15 is provided, the pixel electrode PE and the organic light-emitting layer ORG are not in contact with each other (that is, insulated from each other), and therefore the organic light-emitting layer ORG does not emit light.
The pixel electrode PE is provided on the fourth insulating film 14. The pixel electrode PE is in contact with the drain electrode DE of the switching element SW via a contact hole formed in the fourth insulating film 14, and is electrically connected to the switching element SW. As shown in
The organic light-emitting layer ORG emits light at a luminance according to a voltage (or current) applied between the pixel electrode PE and the common electrode CE. The organic light-emitting layer ORG may include other layers in addition to the light-emitting layer, such as an electron-injection layer, a hole-injection layer, an electron-transport layer, and a hole-transport layer, to improve luminous efficiency.
The common electrode CE is formed on the organic light-emitting layer ORG. The common electrode CE and the pixel electrode PE are formed from, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). Note that though omitted from the illustration, the organic EL device OD should preferably be sealed with a protection film to protect the organic EL device OD from moisture and the like.
The organic EL device OD is covered by a sealing layer 30. The sealing layer 30 is formed to seal the members disposed between the first insulating substrate 10 and the sealing layer 30. The sealing layer 30 inhibits entering of oxygen and moisture to the organic EL device OD, to suppress degradation of the organic EL device OD. The sealing layer 30 may be formed from a stacked layer body of an inorganic film and an organic film.
On the other hand, the second substrate SUB2 comprises a second insulating substrate 20, a color filter layer 21 and the like. The second insulating substrate 20 may be a glass substrate or a resin substrate, or an optical element containing an optical film, a polarizer, etc. The color filter layer 21 is provided on an inner side of the second insulating substrate 20 (that is, a side which opposes the first substrate SUB1). The color filter layer 21 comprises color filters CF. The color filters CF are formed from, for example, resin materials colored red, blue, green, white, etc.
The first substrate SUB1 and the second substrate SUB2 prepared as above are attached together with the sealing layer 30, for example. The color filters CF provided on the second substrate SUB2 are arranged so as to cover at least the light-emitting regions of the organic EL device OD formed on the first substrate SUB1.
In the example illustrated, the organic EL device OD is formed so as to comprise a common organic light-emitting layer ORG provided for a plurality of pixels PX, but the structure thereof is not limited to this. For example, an organic light-emitting layer which emits blue light, an organic light-emitting layer which emits green light, and an organic light-emitting layer which emits red light may be provided for every pixel. In such structure, the color filter layer 21 may be omitted.
In
The second surface 10B is formed such that a distance H2 between the first position P1 closest to the organic EL device OD in the thickness direction of the first insulating substrate 10 and the second position P2 farthermost from the organic EL device OD in the thickness direction becomes 0.01 μm or more but 10 μm or less, preferably, 0.1 μm or more but 10 μm or less. Moreover, in the second surface 10B, also, a distance between a recess and a projection adjacent to each other can be specified. For example, a region A3 is equivalent to a recess, and a region A4 is equivalent to a projection adjacent to the region A3. A distance L2 of a third position P3, which is a bottom of the region A3 and a fourth position P4, which is a top of the region A4 is set to 15 μm or less. Note that a distance H3 between the third position P3 and the fourth position P4 along the thickness direction, that is, the distance H3 along thickness direction between a recess and a projection adjacent to each other is 0.01 μm or more but 10 μm or less, preferably, 0.1 μm or more but 10 μm or less.
In the case where the thickness of the first insulating substrate 10 is greater than 20 μm, for example, the first surface 10A may become more even than the second surface 10B. In other words, a surface coarseness Ra1 of the first surface 10A may be less than a surface coarseness Ra2 of the second surface 10B. In such a case, a distance H1 in the thickness direction between a first position P1 and a second position P2 in the first surface 10A may be less than the distance H2 in the thickness direction of the first position P1 and the second position P2 in the second surface 10B. Or between an adjacent pair of a recess and a projection, a distance L1 between a third position P3 and a fourth position P4 in the first surface 10A may be less than the distance L2 between the third position P3 and the fourth position P4 in the second surface 10B.
Next, a method of manufacturing the display device 1 will be described with reference to
First, as shown in
In the example illustrated, both of the front surface 40A and a rear surface 40B of the glass substrate 40 are formed into rough surfaces, but in order to form a rough-surfaced first insulating substrate 10, it suffices if at least the front surface 40A, on which the first insulating substrate 10 is formed, is formed to be rough. In order to prevent foreign matters from attaching to the glass substrate 40, which will be described later, it suffices if the rear surface 40B is formed to be rough. The above-provided description with reference to
Next, as shown in
Next, an optical layer 43 containing the insulating substrate 20 is attached onto the display function layer 42. The optical layer 43 is equivalent to the second substrate SUB2 shown in
For example, when the glass substrate 40 is cut, glass chips (cullet) may be created while cutting. The rear surface 40B of the glass substrate 40 is formed rough to such an extent that it includes recesses and projections sufficiently smaller than the size of the cullet. Therefore, as shown in
Next, as shown in
The laser beam irradiated onto the glass substrate 40 is of a wavelength of 355 nm. The laser beam is irradiated from under the glass substrate 40 (that is, the rear surface 40B side of the glass substrate 40), and transmitted through the glass substrate 40, and then reaches the second surface 10B of the first insulating substrate 10. The first insulating substrate 10 absorbs the laser beam in the vicinity of the interface between the glass substrate 40 and the first insulating substrate 10, to cause ablation, by which the first insulating substrate 10 is partially decomposed. Thus, a space is created between the glass substrate 40 and the first insulating substrate 10, peeling the glass substrate 40 off from the first insulating substrate 10.
In the example illustrated, a foreign matter is attached to the rear surface 40B of the glass substrate 40. Here, even if a foreign matter is not removed in washing and still attached to the rear surface 40B of the glass substrate 40 as shown in
Next, as shown in
Next, as shown in
Next, as shown in
Next, a support member 50 is aligned and attached to the protection member PP via an adhesive member 51. Then, the bending area BA of the display panel 2 is bent so as to dispose the first circuit substrate 3 and the second circuit substrate 4 below the display area DA. More specifically, the first circuit substrate 3 and the second circuit substrate 4 is pivoted around the support member 50 so as to be located thereunder and attached to the support member 50 via the adhesive member 51. In this embodiment, the thickness of the display panel PNL in the bending area BA is, for example, about 130 μm. Note that the support member 50 need not be provided.
The bending area BA is bent so that the display panel 2 opposes the first circuit substrate 3 and the second circuit substrate 4. In this embodiment, the radius of curvature can be set to 1.0 mm or less and the radius of curvature of the bending area BA is, for example, about 0.3 mm. The support member 50 is located between the protection member PP and the first circuit substrate 3. With the support member 50 provided, the display panel 2 and the first circuit substrate 3 can be protected from being easily damaged even when a shock is applied from outside. Further, with the support member 50, the adhesiveness between the protection member PP and the first circuit substrate 3 can be improved.
Note that the above-described process is an example and the processing steps are not limited to the above-indicated order.
According to this embodiment, the display device 1 comprises the first insulating substrate 10 including the first surface 10A and the second surface 10B, at least one of which is a rough surface. Since the first insulating substrate 10 is formed to have a rough surface, it becomes possible to ease concentration of stress, and therefore the first insulating substrate 10 can be easily bent. Further, when the second surface 10B to be attached to the protection member PP is formed rough as well, the contact area between the second surface 10B and the adhesive member GL is increased, making it possible to improve the adherence of the protection member PP.
Moreover, in the glass substrate 40, the front surface 40A on which the first insulating substrate 10 is formed and the rear surface 40B on the opposite side to the front surface 40A are formed rough, it is possible to suppress foreign matters and the like from attaching to the rear surface 40B of the glass substrate 40. Further, even if a foreign matter or the like attaches to the rear surface 40B of the glass substrate 40, it can be easily removed.
Furthermore, the laser beam to peel the glass substrate 40 off from the first insulating substrate 10 is scattered on the rear surface 40B of the glass substrate 40, and therefore even if a foreign matter is attached to the rear surface 40B of the glass substrate 40, it is possible to apply the laser beam to reach the second surface 10B of the first insulating substrate 10. Thus, the peeling-off error of the glass substrate can be suppressed.
As described above, with use of the glass substrate 40 comprising a rough surface in the manufacture of the display device 1, the yield of the product can be easily improved.
In addition, when the display device 1 is a liquid crystal display, the liquid crystal display may be any of a transmissive type which displays images by selectively transmitting light from a rear side thereof, a reflective type which displays images by selectively reflecting light from a front side thereof and a trans-reflective type comprising a transmissive display function and a reflective display function. When the display device 1 is a liquid crystal display, the above-described display function layer 42 is equivalent to the layers containing a pixel electrode, a liquid crystal layer and a common electrode.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-140364 | Jul 2016 | JP | national |
