KR20180047603A - Foldable display device - Google Patents

Abstract

The present invention relates to a foldable display device which reduces transferring and distortion phenomenon of a folding part, prevents sagging of a display panel and can increase an adhesion property between the display panel and a back cover while having an excellent folding property. The foldable display device of the present invention comprises: the display panel including at least one folding part and an unfolding part on a display region; and the back cover attached to the back surface of the display panel through an adhesion layer. A board is attached to the back surface of the unfolding part. The back cover includes a plurality of segments attached to the back surface of the folding part. The segments are separated from each other and are located so as to be parallel to a folding axis of the folding part.

Description

FOLDABLE DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foldable display apparatus, and more particularly, to a foldable display apparatus capable of reducing transferring and distortion of a folding unit of a foldable display apparatus and preventing deflection of the display panel.

The image display device that realizes various information on the screen is the core technology of the information communication age, and it is becoming thinner, lighter, portable, and higher performance. Accordingly, an organic light emitting display device for displaying an image by controlling the amount of light emitted from the organic light emitting layer by using a flat panel display capable of reducing weight and volume, which is a disadvantage of a cathode ray tube (CRT)

In an organic light emitting display, a plurality of pixels are arranged in a matrix form to display an image. Here, each pixel includes a light emitting element and a pixel driving circuit composed of a plurality of transistors that independently drive the light emitting element.

Since such an organic light emitting display device uses self-emission organic light emitting devices, it does not require a separate light source and can form a spherical shape of an ultra-thin display device. In recent years, organic light emitting devices have been used, The present invention relates to an in-cell touch type display device.

Such a foldable display device has a structure in which the display device itself including the display panel is folded, and a back cover is applied to protect the display panel having such a flexible characteristic. At this time, the back cover that protects the display panel from the back of the display panel should also be designed to be foldable.

The back cover of the conventional foldable display device has a structure in which the region corresponding to the folding portion includes silicone resin and the like and the region corresponding to the other unfolding portion is made of metal or plastic having rigidity And has a structure for protecting the display panel.

In the conventional foldable display device using the back cover, the folding unit and the folding unit are formed using different materials. At this time, the materials have different physical properties such as stiffness, elasticity and ductility, and there is a high possibility that unevenness occurs at the interface between the different materials due to the difference in the degree of compression of the respective materials during the process. As a result, the display screen is transferred and distorted due to the unevenness occurring between the folding unit and the unfolding unit. Further, in the conventional foldable display device using the back cover, the folding area of the flexible structure is stressed several times after the folding, and the display panel is lifted or sagged. In the high temperature and high humidity condition, There is a problem that the outer shape of the resin is deformed or hardened.

SUMMARY OF THE INVENTION The present invention has been conceived in order to solve the above-described problems, and it is an object of the present invention to provide a foldable display device capable of reducing transfer and distortion of a folding portion, preventing deflection of a display panel, And a display device.

According to an aspect of the present invention, there is provided a display apparatus including a display panel including at least one folding unit and a folding unit, and a back cover attached to the backside of the display panel through an adhesive layer. A sheet material is attached to the back surface of the unfolded portion.

The back cover includes a plurality of segments attached to the back surface of the folding portion. Where the segments are spaced apart from one another and are arranged parallel to the folding axis of the folding section.

INDUSTRIAL APPLICABILITY In the present invention, the back cover is formed of a material such as metal having high rigidity of the same kind, so that even when pressure is applied to the display panel at the time of cementing, the thickness of the back cover is not affected at all. Accordingly, the present invention has the effect of preventing not only a high flatness but also a transferring and distortion of the display surface.

Also, the display apparatus according to the present invention has a plurality of segments. When the display panel is folded, the segments do not affect the folding, and accordingly, the foldable display device according to the present invention has excellent folding characteristics.

 The foldable display device according to the second embodiment of the present invention has the effect of securing the position of a segment precisely and ensuring excellent folding characteristics in addition to the effects described in the first embodiment.

FIG. 1 is a schematic view for explaining a foldable display device according to a first embodiment of the present invention, and FIG. 2 is a schematic view for explaining a cross section of a portion II 'of FIG.
3 is a schematic view for explaining the rear surface of the display device of the present embodiment shown in Fig.
FIG. 4 is a side view of a foldable display device according to the present invention, and FIG. 5 is a schematic view for explaining the shape of a support when the foldable display device according to the present invention is folded.
FIG. 6 is a schematic view for explaining a foldable display device according to a second embodiment of the present invention, and FIG. 7 is a schematic view for explaining when the foldable display device of FIG. 5 is folded.
FIG. 8A shows a distortion and a transfer phenomenon of a display surface in a conventional foldable display device, and FIG. 8B shows a display surface 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.

The term " on "or " on" of another element encompasses not only the element just above the other element layer but also intervening layers or other elements in the middle. On the other hand, an element or layer is referred to as being "tangential " to another element, indicating that no other element or layer is interposed.

The sizes and thicknesses of the respective components shown in the figures are shown for convenience of explanation, and the present invention is not necessarily limited to the sizes and thicknesses of the components shown.

FIG. 1 is a schematic view for explaining a foldable display device according to a first embodiment of the present invention, and FIG. 2 is a schematic view for explaining a cross section taken along line I-I 'of FIG.

Referring to FIGS. 1 and 2, the display device 100 includes a display panel 100 including at least one folding unit F / A in a display area, (1000) are bonded together. A region of the display panel 100 excluding the folding portion F / A is defined as a folding portion N / A. In the back cover 1000, a support part 1200 is provided in a region located on the back surface of the folding part F / A. This will be described later.

2, the display panel 100 according to the embodiment of the present invention includes a first substrate 100 bonded to the back cover 1000 through an adhesive layer 110, And a thin film transistor array (140) having pixels formed in a matrix on the first buffer layer (130) and having thin film transistors for each pixel, wherein the first buffer layer (130) A protective layer 160 covering the thin film transistor array 140 and the organic light emitting array 150 except for the pad portion; A second buffer layer 220 formed on the touch electrode array 230 in order, a second substrate 210, and a second substrate 210. The first substrate 210 and the second substrate 210 are bonded to each other with an adhesive layer 400 interposed therebetween, And a cover window 3000 positioned above the second substrate 210.

The display panel according to the present invention is not necessarily limited to the above embodiment, and a foldable display device including the thin film transistor array 140 and the organic light emitting array 150 can be widely applied.

An active area A / A and a dead area D / A are defined in the first buffer layer 130 and the second buffer layer 220, respectively. The active area A / A and the dead area D / A are defined in the first buffer layer 130 and the second buffer layer 220, Thin film transistors in the thin film transistor array 140 except for the portion are formed in the active region A / A. The touch pad portion and the pad portion of the thin film transistor array are defined in a part of the dead region (D / A).

Herein, the first and second substrates 120 and 210 serve to prevent damage to the internal array in a laser irradiation or etching process, and in some cases, And the like. The first and second substrates 120 and 210 may be formed of a polymer material such as polyimide and photoacryl.

The first buffer layer 130 and the second buffer layer 220 are formed by successively stacking inorganic films such as an oxide film (SiO2) or a nitride film (SiNx) in the same kind or alternately stacking different inorganic films. The first and second buffer layers 130 and 210 function as a barrier for preventing moisture or outside air from being permeated into the organic light emitting array 150 in the subsequent process of attaching the upper substrate on the lower substrate.

The touch electrode array 230 and the touch pad portion 2350 are formed on the same surface of the second buffer layer 220. The touch pad portion 2350 is connected to a pad portion (not shown) of the thin film transistor array 140 by a seal 450 including a conductive ball 455 in a top-bottom adhesion process by the adhesive layer 400. At this time, the adhesive layer 400 has a moisture-proof function. In addition to the functions of the protective layer 160 in contact with the protective layer 160 covering the organic light-emitting array 150, And to prevent moisture permeation more surely.

The thin film transistor array 140 including the pads protrudes one side of the touch electrode array 230, and a signal for driving the touch electrode array and the thin film transistor array and the organic light emitting array together But the present invention is not limited thereto. Though not shown, the driving circuit, the thin film transistor array driving pad, and the dummy pads include a plurality of dummy electrodes, and are connected to the driving circuit by wiring. The driving circuit may be controlled by an MCU (Micro Control Unit, not shown) and a timing controller (not shown) provided in the FPCB by being connected to a flexible printed circuit board (FPCB) . The dummy pad is formed in the same layer as the metal forming the gate line or the data line in the region corresponding to the touch pad portion among the dead regions outside the active region. Further, the driving circuit may be mounted on the FPCB or the anisotropic conductive film or the like and provided on the back surface of the display panel 100.

The driving circuit mounted on the flexible printed circuit board or the anisotropic conductive film (ACF) may be mounted by a COF (Chip On Film) method.

 Though not shown, the thin film transistor array driving pad and the dummy pads are connected to the flexible printed circuit board by wiring (not shown). The flexible printed circuit board may further include a controller (not shown) for controlling the driving circuit.

The dummy pad is formed in the same layer as the metal forming the gate line or the data line in the region corresponding to the touch pad portion 2350 of the dead region outside the active region.

Hereinafter, components other than the back cover 1000 and the adhesive layer 110 will be referred to as a display panel 100 for convenience. As described above, the display panel 100 is not necessarily limited to the configuration of FIG. 2, and display devices having various configurations including the thin film transistor array 140 and the organic light emitting array 150 may be applied.

3 is a schematic view for explaining the rear surface of the display device of the present embodiment shown in Fig.

Referring to FIG. 3, a plurality of segments 1203 are attached to a supporting portion 1200 of a back surface of a folding portion F / A of the display panel 100. FIG. Further, a plate member 1204 is provided on the back surface of the unfolding portion N / A. At this time, the segment 1203 and the plate member 1204 may be formed of the same material such as a metal having high rigidity, but the present invention is not limited thereto. At this time, the segment 1203 and the plate member 1204 may be formed of any one of metals having high rigidity such as Fe, Ni, Cr, or an alloy thereof.

Each segment 1203 is spaced apart from and parallel to the folding axis of the folding section F / A. Each of the segments 1203 may extend from one side of the folding portion F / A of the display panel 100 to the other side of the folding portion F / A, But it is not always limited to this.

The thickness of each of the segments 1203 is equal to the thickness of the plate 1204. The folding portion F / A and the folding portion N / A of the display panel 100 are formed of a material having high strength such as metal when the display panel 100 is placed on a flat surface, And is supported by the back cover 1000 having the same height without a step. Therefore, the display device of the present invention has high flatness.

Segments 1203 of the support portion 1200 are formed to have a fine width of 0.03 to 0.1 mm. Also, each segment 1203 is spaced a certain distance from adjacent segments. At this time, the ratio of the width of the segments 1203 to the width of the space between the segments is about 1: 4. For example, if the segments 1203 are formed to have a width of 0.05 mm, the adjacent segments 1203 are preferably spaced about 2 mm apart. That is, although the width of the segment 1203 is shown to be considerably wide in FIGS. 1 and 3 for convenience of explanation, substantially each support portion 1200 forms a fine pattern through each of the segments 1203.

FIG. 4 is a side view of a foldable display device according to the present invention, and FIG. 5 is a schematic view for explaining a shape of a support part 1200 when the foldable display device according to the present invention is folded.

As shown in FIG. 4, the foldable display device according to the present invention supports a folding portion F / A by a plurality of segments 1203 formed to have a minute size and spaced from each other. When the display panel 100 is folded, the segments 1203 are separated from each other at the back surface of the folding portion F / A as shown in FIG. 5 because they have a fine pattern. In other words, when the display panel 100 is folded, the segments 1203 do not affect the folding, and accordingly, the foldable display device according to the present invention has excellent folding characteristics.

On the other hand, the back cover of the conventional foldable display device supports the back surface of the unfolded portion F / A with a hard material and supports the back surface of the folded portion F / A with a material different from the hard material . When the display device is bonded to such a back cover, an adhesive or the like is applied and then attached using a roller or the like. At this time, the soft material is pressed while thinning the soft material, and accordingly, the flatness of the display panel is lowered, Transfer and distortion occurred.

On the other hand, according to the present invention, since the back cover 1000 is formed of a material such as metal having high rigidity of the same kind, even when pressure is applied to the display panel 100 at the time of attaching the back cover 1000, There is no effect at all. Accordingly, the present invention has the effect of preventing not only a high flatness but also a transferring and distortion of the display surface.

FIG. 6 is a schematic view for explaining a foldable display device according to a second embodiment of the present invention, and FIG. 7 is a schematic view for explaining when the foldable display device of FIG. 5 is folded.

The display panel 100 of the folder-type display apparatus according to the second embodiment of the present invention is the same as that of the first embodiment, and has a difference in the shape of the back cover 1000.

The back cover 1000 of the second embodiment includes segments 1203 on the back surface of the folding portion F / A of the display panel 100 as in the first embodiment. The detailed features of the segment 1203 have been described in the first embodiment and will not be described here.

According to the second embodiment, a connection portion 1204 is further provided between the segments 1203. The connection portion 1204 is attached to the back surface of the display panel 100 to connect the segments 1203. At this time, it is preferable that the connection portion 1204 is formed simultaneously with the same material as the segment 1203 through a method such as patterning one metal plate.

At this time, as the thickness of the connecting portion 1204 increases, the folding characteristic of the back cover 1000 decreases, so that the connecting portion 1204 should be formed to have a thickness sufficient to maintain the folding characteristic. At this time, it is preferable that the thickness of the connection portion 1204 has a value between 10 and 20 mu m.

The supporting portion 1200 of the display device of the present embodiment includes a plurality of segments 1203 completely separated from each other. In this case, it is difficult to align the gaps between the segments 1203 completely uniformly, and the possibility that the segment 1203 is erected obliquely to the side also increases. That is, it is very difficult to align the segment 1203 so that the position of the segment 1203 is exactly where desired, and a space that the segment 1203 can not support can occur.

According to the second embodiment, since the segments 1203 are connected to each other by the connecting portion 1204, the segments 1203 are fixed to have a predetermined interval. Accordingly, the segment 1203 is aligned at the correct position and prevents a space that the segment 1203 can not support.

On the other hand, since the connecting portion 1204 has a very thin thickness of 10 to 20 탆, the connecting portion 1205 hardly affects the folding characteristic of the display panel 100.

In other words, the foldable display device according to the second embodiment of the present invention has the effect of securing the position of the segment 1203 accurately and securing excellent folding characteristics, in addition to the effects described in the first embodiment.

FIG. 8A shows a distortion and a transfer phenomenon of a display surface in a conventional foldable display device, and FIG. 8B shows a display surface of the present invention.

Referring to FIG. 8A, it can be seen that the light from the light source incident on and reflected from the upper side is distorted as if it is separated into two.

On the other hand, referring to FIG. 8B, which is a foldable display device according to the present invention, it can be seen that one light source is reflected and visible without distortion.

As described above, the present invention provides a foldable display device that has excellent folding characteristics and high rigidity while securing excellent image quality by improving transferring and distortion of the display surface.

The foregoing description is merely illustrative of the present invention, and various modifications may be made by those skilled in the art without departing from the spirit of the present invention. Accordingly, the embodiments disclosed in the specification of the present invention are not intended to limit the present invention. The scope of the present invention should be construed according to the following claims, and all the techniques within the scope of equivalents should be construed as being included in the scope of the present invention.

100: Display panel 1000: Back cover
120: first substrate 130: first substrate
140: thin film transistor array 150: organic light emitting array
160: protective layer 400: adhesive layer
210: second substrate 220: second buffer layer
230: Touch electrode array 1200: Support
1203: segment 1204: connection

Claims (12)

A display panel including at least one folding portion and a folding portion in a display region,
And a back cover attached to the rear surface of the display panel through an adhesive layer,
Wherein the back cover includes a plurality of segments attached to a back surface of the folding unit. The method according to claim 1,
And a plate member attached to a back surface of the unfolded portion. The method according to claim 1,
Wherein each of the segments is spaced apart from and parallel to the folding axis of the folding unit. 3. The method of claim 2,
Wherein the thickness of each of the segments is equal to the thickness of the plate material. 3. The method of claim 2,
Wherein at least one of the segment and the plate member is made of a metal. 6. The method of claim 5,
Wherein the segment and the plate member are made of the same metal material. The method according to claim 1,
Wherein the ratio of the width of the segment to the width of the space between the segments is about 1: 4. The method according to claim 1,
And the width of the segment has a value between 0.03 and 0.1 mm. The method according to claim 1,
Further comprising: a plurality of connection portions located in an area where the display panel and the segments contact with each other and connecting the segments adjacent to each other. 10. The method of claim 9,
Wherein the thickness of the connection pattern has a value between 10 and 20 mu m. 10. The method of claim 9,
Wherein the connection patterns are integrally formed of the same material as the segments. 12. The method of claim 11,
Wherein the segments and the connection patterns are made of the same metal material.

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