KR20170004662A

KR20170004662A - Backplane substrate and Flexible Display Using the Same

Info

Publication number: KR20170004662A
Application number: KR1020150095330A
Authority: KR
Inventors: 국승희; 윤상천
Original assignee: 엘지디스플레이 주식회사
Priority date: 2015-07-03
Filing date: 2015-07-03
Publication date: 2017-01-11

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backplane substrate which improves the reliability of the device by preventing a change in capacitance due to repeated folding operation by changing the configuration, and a flexible display using the backplane substrate. The backplane substrate of the present invention includes a plurality of pixels A first electrode and a second electrode opposed to each other in a plate shape having a plurality of spaced apart holes in at least one pixel and thin film transistors provided in each pixel; And a capacitor made of an insulating film between the electrodes.

Description

BACKPLANE SUBSTRATE AND FLEXIBLE DISPLAY USING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a backplane substrate and a flexible display using the same, which improves the reliability of the device by preventing a change in capacitance due to repetitive folding operation by changing the configuration.

Specific examples of the flat panel display include a liquid crystal display (LCD) device, an organic light emitting display device, a plasma display panel (PDP) device, a quantum dot display device ), A field emission display device (FED), and an electrophoretic display device (EPD). The flat display panel, which realizes images in common, is an essential component, The flat panel display panel has a structure in which a pair of transparent insulation substrates are bonded together with inherent light emission, polarization, or other optical material layers interposed therebetween.

In recent years, there has been a demand for a flat display device to be used in a flexible form.

Flexible displays are being developed in a form that is gradually thinner and collapsible. However, in the flexible display up to the present, the folding operation is repeated and the number of folding operations is increased, so that the folding portion is damaged, which causes various problems. For example, there is a problem in that the folding portion is not turned on at all because the pixels on the folding portion are damaged due to physical stress when folding. Alternatively, even if a tentative point due to folding or the like is not generated, the electrostatic capacity value in each subpixel changes with elapse of time due to the folding repetition, and image quality deterioration may be a problem in some cases.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and it is an object of the present invention to provide a backplane substrate and a flexible display using the backplane substrate, wherein the reliability of the device is improved by preventing a change in capacitance caused by a repeated folding operation. There is a purpose.

According to an aspect of the present invention, there is provided a backplane substrate including a substrate having a plurality of pixels in a matrix, a thin film transistor provided in each pixel, and a plurality of spaced- First and second electrodes facing each other in a plate shape, and a capacitor made of an insulating film between the first and second electrodes.

Here, the second electrode may include a first layer located under the first electrode and having a plurality of first holes, and a second layer located at an upper portion of the first electrode and having a plurality of second holes, The insulating layer may include a first insulating layer between the first layer and the first electrode, and a second insulating layer between the first electrode and the second layer. In this case, it is preferable that the third holes of the first electrode are located at positions corresponding to the first holes of the first layer and the second holes of the second layer, respectively.

The thin film transistor includes an active layer on the substrate, a gate electrode on the first insulating film corresponding to an upper portion of the active layer, and a source electrode connected to both ends of the active layer, And a drain electrode. It is preferable that the first electrode is located on the same layer as the gate electrode, the first layer is located on the same layer as the active layer, and the second layer is located on the same layer as the source electrode and the drain electrode .

Here, the first layer and the second layer may be electrically connected through a contact hole passing through the first insulating layer and the second insulating layer.

On the other hand, the substrate may include a plastic film and a buffer layer in contact with the active layer and the first layer.

In addition, a flat layer may be further formed on the second layer, the source electrode, and the drain electrode.

The capacitor may have the long sides of the first and second electrodes along the folding axis of the substrate. Alternatively, the capacitor may have a long diagonal line between the first and second electrodes along the folding axis of the substrate.

According to another aspect of the present invention, there is provided a flexible display comprising: a substrate having a plurality of gate lines and data lines crossing each other and defining a plurality of pixels; thin-film transistors provided in the pixels; A capacitor including a first electrode and a second electrode opposed to each other in a plate shape having a plurality of spaced apart holes and an insulating film between the first and second electrodes; a flat layer covering the thin film transistor and the capacitor; And an organic light emitting diode including a first electrode and an organic light emitting layer and a second electrode corresponding to the pixels on the flat layer.

Alternatively, the flexible display of the present invention which achieves the same object includes a first substrate having a plurality of gate lines and data lines crossing each other and defining a plurality of pixels, a thin film transistor provided in each pixel, A first electrode and a second electrode opposed to each other in a plate shape having a plurality of spaced holes in at least one pixel; a capacitor formed of an insulating film between the first and second electrodes; and a capacitor covering the thin film transistor and the capacitor And a second substrate for sealing the liquid crystal layer and the liquid crystal layer on the pixel electrode, and a pixel electrode connected to the pixel electrode.

The backplane substrate of the present invention and the flexible display using the same have the following effects.

First, a plurality of holes are provided in the storage capacitors provided in each subpixel to disperse the stress concentrated on a specific region in the subpixel, thereby preventing an external force from being concentrated, thereby preventing cracking of the subpixel even with external force during folding . Therefore, the reliability of the apparatus can be improved.

Second, by stacking the electrodes constituting the storage capacitor, by matching the holes of each other, the area where the external force is applied is reduced, thereby preventing the change of the storage capacitor and preventing the capacitance from changing even if the folding is repeated. Therefore, image quality can be stabilized.

Figs. 1A and 1B are views showing a flexible display according to the present invention and a folding axis thereof during folding thereof
Figures 2a and 2b show equivalent circuit diagrams of subpixels in the flexible display of the present invention
FIGS. 3A and 3B are plan views showing the arrangement of storage capacitor regions of subpixels according to a light emission type in the flexible display of the present invention. FIG.
4 is a schematic perspective view of a storage capacitor in a flexible display according to the present invention.
5A and 5B are a perspective view and a plan view of a storage capacitor according to a first embodiment of the flexible display of the present invention;
FIG. 6 is a cross-sectional view taken along the line I-I '
Figs. 7A to 7C are plan views showing the respective electrodes of Fig.
8 is a cross-sectional view showing one form of the flexible display of the present invention
9 is a cross-sectional view of a storage capacitor according to a second embodiment of the flexible display of the present invention
10A to 10C are plan views showing a modification of the storage capacitor electrode in the flexible display of the present invention.
11A and 11B are plan views showing a modified example of the hole in the storage capacitor electrode in the flexible display of the present invention.
12A and 12B are plan views showing the arrangement of the storage capacitor region according to a modification of the flexible display of the present invention
13 is a cross-sectional view showing another embodiment of the flexible display of the present invention

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, a detailed description of known technologies or configurations related to the present invention will be omitted when it is determined that the gist of the present invention may be unnecessarily obscured. The component names used in the following description are selected in consideration of easiness of specification, and may be different from the parts names of actual products.

FIGS. 1A and 1B illustrate a flexible display according to the present invention and folding axes thereof when folded. FIG.

1A, the flexible display 100 of the present invention is divided into an active area in which a plurality of sub-pixels SP are arranged in a matrix and a non-active area in the vicinity thereof. And a plurality of pad electrodes (not shown) connected to the driving IC 140 on one side of the flexible display 100 among the nonactive areas, and one side of the flexible display 100 having the pad electrodes is connected to the pad area (150).

Here, the subpixel SP is the smallest unit that can be displayed on the flexible display 100, and is also referred to as a pixel.

3A and 3B), data lines (see DL in FIG. 3A and FIG. 3B), and wirings (not shown in FIG. 3B) connecting the pad electrodes to each other (Not shown).

The non-active region may be covered with a soft bezel.

On the other hand, the flexible display 100 has flexibility as shown in FIG. 1B, and can fold the flexible display 100 toward a certain folding axis. In this case, a force is applied in a direction intersecting the folding axis, and this force causes the flexible display 100 to be bent and stressed. Particularly, the stress is concentrated on a portion having a large bending property. For example, when the flexible display 100 is folded up and down by half, stress is concentrated on a portion on the half-divided line. Here, the halved line is called a folding line, and the folding line follows the folding axis.

The flexible display of the present invention is intended to prevent damage due to stress in the folding operation, in particular, to change the configuration of storage capacitors in individual subpixels. The change of the storage capacitor in the subpixel may be made only for the subpixels disposed around the folding line, or for the entire subpixel.

If the folding line is set to several lines in the flexible display, each of the sub-pixels in the plurality of folding lines may have a configuration change.

Meanwhile, in the flexible display of the present invention, the non-active area including the pad area may be covered with a mechanism such as a bezel, and the folding line may be defined by adjusting the bending property of the structure.

The flexible display of the present invention can be applied to an organic light emitting display panel having a self-luminous element without a separate light source unit, or to a liquid crystal display panel provided in a flexible form to a light source unit. That is, the present invention is applied to a display panel having a storage capacitor requiring a capacitance of each sub-pixel at a certain level. Hereinafter, an equivalent circuit of subpixels for each emission mode is referred to.

2A and 2B are equivalent circuit diagrams of subpixels of the flexible display of the present invention.

2A is a circuit diagram of a subpixel of an OLED display panel. In each subpixel of the active area AA, at least one thin film transistor (S-Tr, D-Tr), a storage capacitor Cst, Cst and an organic light emitting diode (OLED) connected to a thin film transistor (D-Tr). 2A shows an example in which a selection thin film transistor (S-Tr) and a driving thin film transistor (D-Tr) are provided as two thin film transistors, and a thin film transistor can be further added if necessary. The driving thin film transistor D-Tr is electrically connected to the first electrode of the organic light emitting diode OLED. The storage capacitor Cst is connected to the gate electrode of the driving thin film transistor D-Tr, And a transistor (D-Tr) is connected between the connection terminal connected to the first electrode of the organic light emitting diode (OLED). The connection terminal may be a source electrode or a drain electrode of the driving thin film transistor (D-Tr). If the drain electrode is connected, the source electrode is connected to the driving current line VDL to receive the driving voltage. When the source electrode is connected only, the drain electrode is connected to the driving current line VDL.

In addition, the circuit portion is provided between the gate line GL and the data line DL which intersect each other and are located at the boundary of the subpixel. The driving current line VDL is disposed in parallel to the data line DL and spaced apart from the data line DL of the adjacent sub-pixel. The selective thin film transistor S-Tr is connected between the gate line GL and the data line DL and is connected to a gate electrode of a driving thin film transistor (D-Tr) connected to the storage capacitor, According to the selective driving of the selective thin film transistor (S-Tr), current is supplied to the organic light emitting diode through the driving thin film transistor (D-Tr) to control ON / OFF of the organic light emitting diode.

2B is a basic circuit diagram of a liquid crystal display panel. In each subpixel defined by a plurality of gate lines GL and a plurality of data lines DL, a thin film transistor (TFT) And a liquid crystal capacitor Clc connected to the liquid crystal capacitor Clc. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the thin film transistor, and a common electrode arranged between the pixel electrode and the liquid crystal. The thin film transistor supplies a video signal from each data line DL to the pixel electrode in response to a scan pulse from each gate line GL.

The liquid crystal capacitor Clc charges the difference voltage between the video signal supplied to the pixel electrode and the common voltage SVcom applied to the common electrode and adjusts the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage Thereby implementing the gradation. In this case, the storage capacitor Cst has a function of maintaining the voltage charged in the pixel electrode, and may be formed by overlapping the insulating film between the pixel electrode and the storage line.

As shown in FIGS. 2A and 2B, when a flexible display is implemented by a display panel including a storage capacitor, all of the storage capacitors can be used. The storage capacitor occupies an area within a subpixel, and can be arranged as follows according to a light emission scheme.

3A and 3B are plan views showing the arrangement of a storage capacitor region of a subpixel according to a light emission type in the flexible display of the present invention.

FIG. 3A shows a configuration in which the storage capacitor ST region is disposed between the gate line GL and the data line DL in the case of the top emission type of the OLED display panel. In the flexible display of the present invention, the storage capacitor includes a plurality of holes on a plate, and first and second electrodes provided in the same position with each other and an insulating film therebetween. The organic light emitting diode (OLED) for light emission may be disposed over the storage capacitor ST region. Therefore, the storage capacitor (ST) region can be arranged freely without affecting the display, and can be arranged with a large area in the sub-pixel (SP).

The selective thin film transistor S-Tr and the driving thin film transistor D-Tr, which are circuit structures except for the organic light emitting diode OLED of FIG. 2A, are arranged in a sub-pixel outside the region of the storage capacitor ST .

FIG. 3B illustrates a case in which the organic light emitting display panel is implemented as a bottom emission type and a storage capacitor ST region in the case of implementing a liquid crystal display panel. The light emitting region EM or the pixel display region PX is a storage Are arranged so as not to overlap with the capacitor (ST) region. That is, in the case of the organic light emitting display panel of the lower emission type, the light emission is directed downward from the light emitting region EM. When the light emitting region EM overlaps with the wiring portion of the circuit, The storage capacitor ST region made of the wiring component is separated from the light emitting region EM. Also, in the case of the liquid crystal display panel, light from the lower light source unit is transmitted to the upper side and display is performed, so that a portion where the storage capacitor ST including the wiring and the pixel display region PX are overlapped The pixel display region PX and the storage capacitor ST region are spaced apart from each other.

In FIG. 3B, the organic light emitting display panel of the lower emission type and the liquid crystal display panel may be different depending on whether or not the driving current line VDL is present. That is, the case where the driving current line VDL is provided is the organic light emitting display panel of the lower emission type.

On the other hand, the ratio of the storage capacitor to the subpixel may vary depending on the light emitting mode or the like, but the flexible display of the present invention can be commonly applied to all display panels having storage capacitors. Further, the present invention can be applied not only to storage capacitors but also to other capacitor structures having electrodes on a plate.

4 is a schematic perspective view of a storage capacitor in the flexible display of the present invention.

4, the storage capacitor of the flexible display of the present invention includes first and second electrodes 105 and 120 facing each other in a plate shape having a plurality of spaced holes 105a and 120a, And an insulating film (not shown) between the second electrodes 105 and 120.

The reason why the first electrode 106 and the second electrode 120 are provided with the holes 105a and 125a is to disperse the stress applied in a specific direction due to the external force at the time of folding.

Table 1 shows the stress applied to the central region when the pattern layer is applied on one plate and divided into a plurality of patterns on the plastic film.

That is, in the first example, in the case of the pattern layer on one plate, the stress applied to the central region is converted to 7.7 MPa, while when divided into a plurality of patterns of the second example, the stress of about 0.3-1.1 MPa Respectively. When at least the pattern layer was divided into a plurality of patterns, it was confirmed that the stress was reduced by 7 times or more.

In the examples of the two patterns, the thicknesses of the plastic film and the pattern layer (pattern) are the same as 20 占 퐉 and 1 占 퐉, respectively. In the first and second examples, Of the population.

rescue Laminated structure Central area stress (MPa) Example 1

Pattern layer 7.7 Plastic film Example 2

Multiple pattern 0.3-1.1 Plastic film

That is, referring to the experimental results of Table 1, the storage capacitor of the present invention has the first and second electrodes provided with a plurality of holes, and by the effect of separating the first and second electrodes, The mechanical stress applied to the electrode is lowered. Unlike the second example of Table 1, the first and second electrodes of the present invention have a plurality of holes that are not island-shaped, in order to apply a common voltage signal to the first and second electrodes, In order to connect them to each other. However, on the straight line passing through the holes, each electrode has a separate effect and has the effect of reducing the stress to the same level as the second example.

And, even if the folding operation is repeated, since the storage capacitor is resistant to stress, the capacitance can be maintained at a substantially constant level without change. Thus, the driving current characteristics can be stabilized in individual subpixels, and the image quality can be kept constant.

* First Embodiment *

5A and 5B are a perspective view and a plan view showing a storage capacitor according to the first embodiment of the flexible display of the present invention, FIG. 6 is a sectional view taken along the line I-I 'of FIG. 5B, And FIG.

The first embodiment of the present invention is characterized in that the second electrode 220 is positioned at the upper and lower positions 2201 and 2202 with respect to the first electrode 210 as shown in FIGS. 5A and 6, The first and second holes 2201a and 2202a are formed in the same region, and three layers of electrodes 2201, 210 and 2202 are stacked.

5A to 7C, the storage capacitor according to the first embodiment of the present invention includes a first layer second electrode 2201 having a plurality of first holes 2201a on a plate, A gate insulating layer 113 covering the first layer second electrode 2201 and a second hole 210b having a third hole 210a corresponding to the first holes 2201a on the gate insulating layer 113, An interlayer insulating film 115 covering the first electrode 210 and a second electrode 210 corresponding to the first hole 2201a and the third hole 210a on the interlayer insulating film 115, And a second layer second electrode 2202 having a hole 2202a.

The first layer second electrode 2201 and the second layer second electrode 2202 are electrically connected to each other and have a first contact hole (CNT1).

The surface of the second layer second electrode 2202 is covered with a protective film 123. A flat layer 125 is formed on the protective layer 123 to flatten the unevenness of the surface of the protective layer 123 by the unevenness of the holes 2201a, 210a and 2202a of the storage capacitor.

The first layer second electrode 2201 and the second layer second electrode 2202 have substantially the same shape in plan view, but in the case of the first electrode 210, the first layer second electrode 2201 and the second layer second electrode 2202 The second layer 2202 is removed at the first contact hole CNT1 to prevent a short circuit between the first electrode 210 and the second electrode 2202 or 2202. [

The first through third holes 2201a, 210a and 2202a are located at corresponding positions with respect to one another in a layered manner and the first and second electrodes 220 and 2201 and 2202 ) Have the same dispersion effect.

The first through third holes 2201a, 210a, and 2202a may be spaced apart from each other at equal intervals on the respective plates, or irregularly spaced from each other. In the latter case, the distance may be adjusted considering the distance to the folding line.

The substrate 110, which is not described above, is formed by laminating a heat-resistant transparent plastic film 111 and a buffer layer 112. Here, the buffer layer 112 is in contact with the first layer second electrode 2201 of the storage capacitor and the active layer 301 of the thin film transistor.

The heat-resistant transparent plastic film 111 may be a copolymer, a polyimide or a polyimide-containing copolymer, an olefin-based copolymer, a polyacrylic acid copolymers comprising polyacrylic acid, polyacrylic acid, copolymers comprising polystyrene or polystyrene, copolymers including polysulfates or polysulfates, polycarbonates or polycarbonates, A copolymer comprising polyamic acid or polyamic acid, a copolymer including polyamine and polyamic acid, a copolymer selected from the group consisting of polyvinylalcohol, polyallyamine, Or more, and the thickness thereof is preferably 5 占 퐉 to 100 占 퐉, Respectively.

In addition, the buffer layer 112 may be formed of an inorganic film, for example, a single layer of SiNx or SiO2, or a continuous layer or an alternating layer thereof. Such a buffer layer functions to prevent penetration of outside air or moisture, and the total thickness of the buffer layer is not more than 10 mu m so as not to increase the thickness of the entire flexible display.

8 is a cross-sectional view showing one embodiment of the flexible display of the present invention.

Referring to FIG. 8, the positional relationship between the storage capacitor and the thin film transistor in the flexible display of the present invention will be described.

8, the thin film transistor includes an active layer 301 on a substrate 110, a gate electrode 310 formed on the gate insulating film 113 in correspondence with the upper portion of the active layer 301, And a source electrode 321 and a drain electrode 322 which are connected to both ends of the layer 301 through the second and third contact holes CNT2 and CNT3 and over the interlayer insulating layer 115, respectively. The first electrode 210 of the storage capacitor is located on the same layer as the gate electrode 310 and the first electrode 2201 of the first layer is located on the same layer as the active layer 301, The second layer second electrode 2202 is located on the same layer as the source electrode 321 and the drain electrode 322. In this case, the electrodes located on the same layer are made of the same material as the component located on the same layer. For example, the first electrode 210 is made of the same material as the gate electrode 310, the first layer first electrode 2201 is made of the active layer 310 material, and the second layer second electrode 2202 are made of the same material as the source electrode 321 and the drain electrode 322. That is, although the storage capacitor of the present invention differs from the general structure in its shape, it can be formed together in the process of forming a thin film transistor without adding a separate process, thereby ensuring stable storage capacitance without burdening the additional process It is possible.

The active layer 310 may be an amorphous silicon layer, a crystalline silicon layer, or an oxide semiconductor layer. The material of the active layer 310 may be selected depending on the mobility or reliability characteristics required for the region.

4, the second electrode 2201 of the first layer having a single layer may be omitted, and the second electrode 2201 may be the same as the source electrode 321 and the drain electrode 322 The second electrode can be formed only in the layer.

In addition, impurities are doped at both ends of the active layer 301 connected to the source electrode 321 and the drain electrode 322, and the active layer 301 has a channel between the impurity doped regions. At this time, the channel is located at a portion overlapping the gate electrode 310.

In addition, since the first layer second electrode 2201 of the second electrode of the storage capacitor functions as an electrode, it is made of the active layer 301 material, and the resistivity is low due to doping with impurities. The first electrode 210 of the first layer 210 is electrically connected to the second electrode 2202 of the first layer 2201 through the contact hole CNT1 to receive a voltage signal. The second layer second electrode 2202 is integrally connected to the drain electrode 322. The drain electrode 322 and the second layer second electrode 2202 receive the same voltage signal. The contact hole CNT1 is defined through the interlayer insulating layer 115 and the gate insulating layer 113. The second layer second electrode 2202 enters the contact hole CNT1, Layer first electrode 2201. The first electrode 2201 is connected to the first electrode 2201.

A protective film 123 is formed to cover the upper portion of the source electrode 321 and the drain electrode 322 and the second layer second electrode 2202. A protective film 123 is formed on the protective film 123, A flat layer 125 is formed to compensate for the planarization. In some cases, the protective film 123 may be omitted and only the flat layer 125 may be provided.

The drain electrode 322 is connected to the first OLED electrode 331 of the organic light emitting diode OLED through the fourth contact hole CNT4 provided in the flat layer 125 and the protective layer 123. [

A bank 325 defining a light emitting region is formed on the flat layer 125, and a portion where the bank 325 is not formed functions as a light emitting region.

An organic light emitting layer 332 is formed on the first OLED electrode 331 and a sidewall of the bank 32 and a second OLED electrode 333 is formed on the organic light emitting layer 332. The first OLED electrode 331, the organic light emitting layer 332 and the second OLED electrode 333 constitute an organic light emitting diode (OLED). 8 includes a top emission type organic light emitting diode to form a flexible display, and a light emission region is defined by overlapping a storage capacitor ST region. In some cases, in the case of the bottom emission type, the light emitting region where the organic light emitting diode (OLED) is formed and the storage capacitor region are not overlapped with each other. In both of the light emitting modes, the thin film transistor and the storage capacitor have a backplane substrate in the same shape.

9 is a cross-sectional view illustrating a storage capacitor according to a second embodiment of the flexible display of the present invention.

As shown in FIG. 9, the storage capacitor according to the second embodiment of the flexible display of the present invention has a structure in which, in addition to the structure in which the electrodes have a plurality of holes, the insulating films also correspond to the holes.

That is, the storage capacitor according to the second embodiment includes a first layer electrode 3201 having a plurality of first electrode holes, a second layer electrode 3201 on the substrate 110 made of a heat-resistant transparent plastic film 111 and a buffer layer 112, A gate insulating film 313 formed on the first layer electrode 3201 and having a gate insulating film hole and a second layer electrode having a second electrode hole corresponding to the first electrode hole on the gate insulating film 311, An interlayer insulating film 315 having an interlayer insulating film hole on the second layer electrode 310 and a third layer electrode 3202 formed on the interlayer insulating film 315. The third layer electrode 3202 is electrically connected to the first layer electrode 3201 through the first contact hole CNT1 passing through the interlayer insulating layer 315 and the gate insulating layer 313. [

The interlayer insulating film 315 and the insulating film hole 3500A of the gate insulating film 313 may be formed to have substantially the same size in the regions corresponding to each other and prevent shorting between the electrodes 3201, It is possible to have a smaller diameter in comparison with the electrode holes of the electrodes 3201, 310 and 3203 of the layers.

A protective layer 123 is formed on the third layer electrode 3202. A flat layer 125 is formed on the third layer electrode 3202 to compensate for unevenness of the storage capacitor. In some cases, the protective film 123 may be provided with an insulating film hole having the same diameter as the above-described insulating film hole 3500A.

As described above, with respect to the storage capacitor, the rigidity of the storage capacitor can be further improved if each electrode has not only the electrode hole but also the insulating film hole correspondingly.

Hereinafter, a modification of the storage capacitor will be described.

10A to 10C are plan views showing a modification of the storage capacitor electrode in the flexible display of the present invention.

10A shows a shape in which a first electrode and a second electrode on a plate forming a storage capacitor ST have a long side along a folding axis. At this time, the two-dimensional shape of the plate is rectangular.

Since the force is applied in the direction perpendicular to the folding axis when folding, the mechanical stress is greater toward the direction perpendicular to the folding axis. The inventors of the present invention compared the mechanical stress along the folding axis and the mechanical stress in the direction perpendicular to the folding axis, and as a result, it was confirmed that the mechanical strain was large in the latter case.

With attention paid to such a change in the mechanical strain, FIG. 9A shows that the first and second electrodes constituting the storage capacitor are elongated along the folding axis. Such a long-side arrangement has rigidity against the external force to be received at the time of folding, and furthermore, when the plurality of holes described above are provided on the plates of the first and second electrodes, such stiffness is further complemented.

FIG. 10B shows a configuration in which the plates of the first electrode and the second electrode forming the storage capacitor ST are formed in a diamond shape in two dimensions, and a long diagonal line is arranged along the folding axis. In this case, the storage capacitor ST can maintain the rigidity because the main direction of the electrode follows the folding axis and the main direction of the electrode of the storage capacitor crosses in the direction in which the external force is applied at the time of folding.

10B shows a case where one side of the diamond shape has an angle of 45 DEG with respect to the folding axis. However, the present invention is not limited to this case, and one side of the polygon may have an angle of 1 DEG to 89 DEG In the range of the angles of the angles.

In the case of FIGS. 10A to 10C, the first and second electrodes of the storage capacitor are provided with a plurality of holes in the plate, and the holes of the first electrode and the holes of the second electrode are provided at the same position. In addition, one of the first electrode and the second electrode may be formed in a two-layer form, as described in the first embodiment, in which case the two-layer electrodes have different layers, You can have a connection. Holes in different layers can also be located at the same position.

11A and 11B are plan views showing modifications of the holes in the storage capacitor electrode in the flexible display of the present invention.

As shown in FIG. 11A, the holes provided in the respective electrodes of the storage capacitor may be formed in a circular shape as well as a rectangular shape as shown above, and circular and square may be formed by mixing together, as shown in FIG. 11B .

In any case, in the present invention, the holes provided in each electrode of the storage capacitor are set to a size capable of maintaining a constant voltage on a plate-shaped electrode and having a dispersing force with respect to an external force at the time of folding.

On the other hand, in the flexible display of the present invention, the major axes of the subpixels can be arranged in the lateral direction. This arrangement modification is intended to facilitate the arrangement of the storage capacitors of Figs. 10a to 10c with diagonal lines of the long side or the long side relative to the folding axis, and when changing the long axis of such sub pixels in the lateral direction, It is advantageous for pixel design to be applied to all the subpixels in common.

12A and 12B are plan views showing the arrangement of a storage capacitor region according to a modification of the flexible display of the present invention.

12A shows that the storage capacitor (ST) region and the light emitting region (EM) are superimposed on the subpixel SP in the top emission type, and these regions are the same as those in which the long axes of the subpixels are arranged along the folding axes The long side follows the folding axis.

12B shows a bottom emission type in which the storage capacitor ST and the emission region EM are separated from each other in the subpixel SP. In the same way as in FIG. 11A, the storage capacitor ST ST) is arranged.

13 is a cross-sectional view showing another embodiment of the flexible display of the present invention.

FIG. 13 shows an example in which the flexible display of the present invention is applied to a liquid crystal display panel, and includes the same thin film transistor (TFT) and storage capacitor ST as described in FIG. 8, and the thin film transistor TFT and the storage capacitor ST A pixel electrode 425 connected to the drain electrode 322 in place of the organic light emitting diode and a liquid crystal layer 423 formed on the flat layer 423 and the pixel electrode 425, A transparent plastic film 435 having a layer 427 opposite to the liquid crystal layer 427 and a common electrode 430 facing the liquid crystal layer 427; 1 and the second polarizing plates 441 and 442.

In this case, the liquid crystal layer 427 may be adhered as a thin film between the common electrode 430, the flat layer 423, and the pixel electrode 425 using a nano liquid crystal, so that the sealing process can be omitted.

The transparent plastic film 435 may be made of a copolymer including a polyester or a polyester, a polyimide or a polyimide, which is a material of the above-mentioned transparent plastic film, A copolymer comprising an olefinic copolymer, a polyacrylic acid or a polyacrylic acid, a copolymer including polystyrene or polystyrene, a copolymer containing a polysulfate or a polysulfate, a polycarbonate ( a copolymer including a polycarbonate or a polycarbonate, a copolymer including a polyamic acid or a polyamic acid, a copolymer including a polyamine and a polyamic acid, a polyvinylalcohol, 0.0 > polyallyamine < / RTI > may comprise one or more polymeric compounds selected from the group consisting of And has a thickness of 5 占 퐉 to 100 占 퐉.

Although not shown in the lower part of the first polarizing plate 441, a flexible light source may be provided.

The flexible display of the present invention can be realized in the form of a display panel of various light emitting modes including a storage capacitor. The flexible display includes a plurality of holes in electrodes of storage capacitors provided in each sub pixel, So as to disperse the stress applied to each sub pixel when folded. Thus, electrode cracking due to stress can be prevented, and ultimately, the storage capacitance can be prevented from changing, thereby stabilizing the image quality.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Will be apparent to those of ordinary skill in the art.

100: flexible display 110: substrate
111: heat-resistant transparent flaky stick film 112: buffer layer
113: gate insulating film 115: interlayer insulating film
105: first electrode 120: first electrode
105a: first hole 120a: second hole
210: first electrode 220: second electrode
2201: first layer second electrode 2202: second layer second electrode
2201a: first hole 2202a: second hole
210a: third hole CNT1 to CNT4: contact hole
310: active layer 310: gate electrode
321: source electrode 322: drain electrode
125, 423: flat layer 331: first OLED electrode
332: organic light emitting layer 333: second OLED electrode
325: bank 425: pixel electrode
427: liquid crystal layer 430: common electrode
435: transparent plastic film 441: first polarizer plate
442: second polarizer plate

Claims

A substrate having a plurality of pixels on a matrix;
A thin film transistor provided in each pixel; And
A backplane substrate comprising first and second electrodes facing each other in a plate shape having a plurality of spaced holes in at least one pixel and a capacitor made of an insulating film between the first and second electrodes.

The method according to claim 1,
Wherein the second electrode comprises a first layer located under the first electrode and having a plurality of first holes and a second layer positioned over the first electrode and having a plurality of second holes,
Wherein the insulating film includes a first insulating film between the first layer and the first electrode, and a second insulating film between the first electrode and the second layer.

3. The method of claim 2,
Wherein the third holes of the first electrode are respectively in a position corresponding to the first holes of the first layer and the second holes of the second layer.

3. The method of claim 2,
The thin-
A gate electrode on the first insulating film corresponding to an upper portion of the active layer, and a source electrode and a drain electrode which are respectively connected to both ends of the active layer and are located above the second insulating film, .

5. The method of claim 4,
The first electrode is located on the same layer as the gate electrode,
Wherein the first layer is located on the same layer as the active layer,
And the second layer is located on the same layer as the source electrode and the drain electrode.

3. The method of claim 2,
Wherein the first layer and the second layer are electrically connected through a contact hole passing through the first insulating film and the second insulating film.

3. The method of claim 2,
Wherein the substrate comprises a plastic film and a buffer layer in contact with the active layer and the first layer.

3. The method of claim 2,
And a flat layer is further formed on the second layer, the source electrode, and the drain electrode.

The method according to claim 1,
Wherein said capacitor has a long side of said first and second electrodes along a folding axis of said substrate.

The method according to claim 1,
Wherein the capacitor has a long diagonal line of the first and second electrodes along the folding axis of the substrate.

A substrate having a plurality of gate lines and data lines crossing each other and defining a plurality of pixels;
A thin film transistor provided in each pixel;
A capacitor including at least one pixel including first and second electrodes facing each other in a plate shape having a plurality of spaced apart holes and an insulating film between the first and second electrodes;
A flat layer covering the thin film transistor and the capacitor; And
And an organic light emitting diode including a first electrode and an organic light emitting layer and a second electrode corresponding to the respective pixels on the flat layer.

A first substrate having a plurality of gate lines and data lines crossing each other and defining a plurality of pixels;
A thin film transistor provided in each pixel;
A capacitor including at least one pixel including first and second electrodes facing each other in a plate shape having a plurality of spaced apart holes and an insulating film between the first and second electrodes;
A flat layer covering the thin film transistor and the capacitor;
A pixel electrode connected to the thin film transistor;
A liquid crystal layer on the pixel electrode; And
And a second substrate for sealing the liquid crystal layer.