KR102662279B1 - Flexible Display and Electronic Device Including the Same - Google Patents

Abstract

The flexible display of the present invention can stably support the display panel even during repeated folding and unfolding operations by varying the configuration of the back plate, and can prevent a specific configuration from sagging or changing shape within the device. It relates to flexible displays and electronic devices including the same.

Description

Flexible display and electronic device including the same}

The present invention relates to a flexible display, and more specifically, to a flexible display that maintains rigidity and reliability even during frequent folding operations, and a device including the same.

Video displays, which implement various information on the screen, are a core technology of the information and communication era and are developing into thinner, lighter, and higher performance. Accordingly, flat displays that can reduce the weight and volume, which are disadvantages of cathode ray tubes (CRTs), and organic light-emitting displays that emit self-luminescence and thus can omit a light source unit, are attracting attention.

Organic light emitting displays display images by arranging multiple pixels in a matrix form. Here, each pixel includes a light-emitting element and a pixel driving circuit consisting of a plurality of transistors that independently drive the light-emitting element.

Meanwhile, recently, from the perspective of various applications, the demand for flexible displays that are easy to carry in a pocket or small pouch and can display images on a larger screen than when carried is increasing. The flexible display can be folded or partially bent when carrying or storing, but can be implemented in an unfolded state when displaying an image, thereby increasing the image display area and improving the user's viewing experience and realism.

Meanwhile, a flexible display includes a display panel on which an image is displayed and a backplate that supports and protects the display panel from the bottom.

The backplate is made of a material with higher rigidity than the display panel and protects the display panel from the lower side. However, since the backplate has a greater difference in rigidity than the display panel, when folding and unfolding operations are repeated, damage such as cracks may occur in the display panel due to the hard backplate in the folding portion.

In order to prevent damage to the display panel, when a backplate with similar rigidity as the display panel is provided, the specific gravity of the backplate is low, so the backplate cannot fully support the display panel, and the flexible display maintains a certain shape in the unfolded state. Failure to do so may cause visual impairment to the user.

Accordingly, flexible displays to date cannot maintain reliability even through repeated folding/unfolding operations, and thus improvement is required. Additionally, because there is a difference in rigidity between components, efforts are being made to prevent damage to the relatively soft display panel.

The present invention was developed to solve the above-mentioned problems. By changing the configuration of the back plate, the display panel can be stably supported even during repeated folding and unfolding operations, and the display panel can be stably supported in the device without sagging or changing shape. The problem to be solved is to provide a flexible display that can prevent changes and an electronic device including the same.

The flexible display of the present invention can stably support the display panel even during repeated folding and unfolding operations by varying the configuration of the back plate, and can prevent a specific configuration from sagging or changing shape within the device. It relates to flexible displays and electronic devices including the same.

The flexible display of the present invention according to one embodiment is divided into a display panel, a folding portion, and a non-folding portion, and includes a first layer of a material having higher rigidity than the display panel, and a second layer in the first layer corresponding to the folding portion. It may include a back plate including a first opening pattern having a density of 1 and a second opening pattern having a second density lower than the first density in the first layer corresponding to the non-folding portion.

Additionally, the non-folding portion may be divided into two or more regions, where one region may have a second opening pattern of the second density, and the remaining region may have a third opening pattern of a density different from the first and second densities.

As the distance from the folding part increases, the specific gravity of the back plate including the opening pattern may decrease.

Additionally, the first density is fixed in the folding part, and the second density in the non-folding part may gradually decrease as the distance from the folding part increases.

The first layer may include at least one of stainless steel, amorphous metal, amorphous silicon, and Invar.

The back plate may further include a skin layer on at least one side of the first layer.

A first adhesive layer may be further provided between the display panel and the backplate.

The skin layer may be made of resin.

The resin may be filled in the first and second opening patterns.

The backplate may further include a second adhesive layer between the first layer and the skin layer.

Additionally, the skin layer may be made of a material with higher elastic recovery force than the first layer.

The skin layer may include at least one of stainless steel, amorphous metal, amorphous silicon, and Invar.

The second adhesive layer may be exposed through the first and second opening patterns.

The first and second opening patterns between the second adhesive layer and the surface of the first layer that is not in contact with the second adhesive layer may have a space less than or equal to the thickness of the first layer.

There are a plurality of first opening patterns in the folding part, and each of the first opening patterns may be formed to be long in one direction.

The first opening pattern is arranged in a plurality of columns, and each column may be divided into a plurality of pieces with a discontinuity therebetween. In this case, the first opening pattern may be located in rows where discontinuities are different from each other in adjacent columns.

The skin layer may be thinner than the first layer.

A region in which the first and second opening patterns are not provided may be further included at a border of the folding portion within the first layer of a certain width.

Additionally, the electronic device of the present invention for achieving the same purpose may include the above-described flexible display and a case for storing the flexible display.

The flexible display of the present invention and an electronic device using the same have the following effects.

First, by equipping the back plate supporting the display panel with an opening pattern with a different specific gravity in the folded portion and the non-folded portion, the back plate can also be folded in accordance with the folding operation of the display panel, and at the same time, when unfolded, the back plate can be non-folded. It is possible to prevent pattern deviation between the part and the folding part from being recognized.

Second, by providing a skin layer with lower rigidity than the backplate main body on the surface of the backplate and filling the opening pattern with the material of the skin layer, it is possible to prevent the opening pattern from being visible due to empty space.

Third, in addition to providing an opening pattern in the folding part, the opening pattern in the non-folding part is provided sequentially or in a gradient manner with a difference in density, thereby reducing the difference in stiffness between regions of the back plate and preventing shape imbalance in which a specific part sags. there is.

Fourth, the skin layer opposing the main body of the back plate with the adhesive layer in between is formed of an alloy layer or amorphous silicon inorganic material with better elastic recovery than the main body, thereby ensuring ductility and at the same time forming (etching) the opening pattern. By solidifying the adhesive layer, the skin layer maintains a flat shape, thereby preventing cracks in the display panel due to external forces during use, such as touch.

1 is a cross-sectional view showing an electronic device including a flexible display according to a first embodiment of the present invention.
Figure 2 is a plan view showing the backplate of Figure 1
3A to 3C are cross-sectional views showing lines I to I', lines II to II', and lines III to III' of FIG. 2.
FIGS. 4A and 4B are simulation diagrams showing the density and rigidity of the pattern in each region of FIG. 2
5 is a plan view showing a backplate according to a comparative example.
Figures 6a and 6b are simulation diagrams showing the density and rigidity of patterns in each region of the backplate according to a comparative example.
7A and 7B are simulation diagrams showing the flatness between the comparative example and the backplate of the present invention.
8 is a photograph corresponding to the first area of the backplate of the present invention
9A to 9C are plan views showing various embodiments of the backplate of the present invention.
Figure 10 is a cross-sectional view showing an electronic device including a flexible display according to a second embodiment of the present invention.
Figure 11 is a cross-sectional view showing the backplate of Figure 10
FIGS. 12A to 12C are cross-sectional process views showing a method of manufacturing the backplate of FIG. 11.
FIG. 13A is a plan view showing the folding portion of the back plate of FIG. 11 and its surroundings according to one embodiment.
Figure 13b is an enlarged perspective view of Figure 13a
FIG. 14A is a plan view showing the folding portion of the back plate of FIG. 11 and its surroundings according to another embodiment.
Figure 14b is an enlarged perspective view of Figure 14a
15 is a cross-sectional view showing the display panel of the flexible display of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. Like reference numerals refer to substantially the same elements throughout the specification. In the following description, if it is determined that a detailed description of a known technology or configuration related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Additionally, the component names used in the following description were selected in consideration of the ease of writing specifications, and may be different from the component names of the actual product.

In addition, when a device or layer is referred to as “on” or “on” another device, it includes not only cases directly on top of another device layer, but also cases where another layer or other device is interposed. On the other hand, when an element or layer is referred to as being “in contact with” another element, it indicates that there is no intervening other element or layer.

The size and thickness of each component shown in the drawings are shown for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the components shown.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.

The displays of the embodiments described below represent a foldable display in which the center of the display is folded and a bendable display in which the edges are folded, but the folding area may be in any part of the display, and the present invention In the flexible display, the deformation of the lower plate and the magnetic material corresponding to the folding area can be applied together by changing their positions according to the area change of the folding area of the display. In addition, the flexible display of the present invention can be used by various names, such as foldable, bendable, and rollable, as long as it is flexible.

*Electronic device including a flexible display according to the first embodiment*

1 is a cross-sectional view showing an electronic device including a flexible display according to a first embodiment of the present invention.

As shown in FIG. 1, the flexible display 1000 according to the first embodiment of the present invention includes a flat display panel 100 and a backplate 200 supporting the display panel 100 from the bottom.

An adhesive layer (adhesive sheet) (not shown) is interposed between the lower surfaces of the display panel 100 and the back plate 200 so that they can be attached to each other, and a case 400 in which the display panel 100 and the back plate 200 are stored. It can be stored in the case 400 by adding a fixing device to it.

The electronic device of the present invention refers to a configuration including a display panel 100, a backplate 200, and a case 400. The electronic device may further include a flexible printed circuit board (not shown) on one side to apply an electrical signal to the display panel 100, and this can be folded and attached between the back plate 200 and the case 400. .

In addition, a board with a heat dissipation or shielding function and a battery (not shown) may be added between the back plate 200 and the case 400.

Meanwhile, the flexible display 1000 of the present invention, as its name suggests, can be folded or bent, and each component is flexible, allowing folding, bending, etc.

In particular, the display panel 100 on which images are displayed is manufactured in a thin film form by omitting hard materials such as glass.

Since the display panel in an electronic device cannot support a certain shape by itself and is vulnerable to external stimuli, a back plate 200 with greater rigidity than the display panel is provided on the lower surface opposite to the surface on which the image is displayed. .

For example, the back plate 200 may be made of stainless steel (SUS: Stainless Use Steel) or a plastic material with high hardness to maintain a certain thickness. Alternatively, the back plate 200 may be formed of an amorphous metal or Invar material.

The flexible display 100 of the present invention will be described in detail later in that the shape of the back plate 200 has been changed to prevent damage to the portion of the display panel 100 corresponding to the relatively soft folding portion.

Figure 2 is a plan view showing the backplate of Figure 1. 3A to 3C are cross-sectional views showing lines I to I', lines II to II', and lines III to III' of FIG. 2.

2 to 3C, the backplate 200 used in the flexible display of the present invention is divided into a folding part (FR) and a non-folding part (UFR), and is higher than the display panel (see 100 in FIG. 1). It has a first layer 200a of a material having rigidity, a first opening pattern 205a having a first density in the first layer corresponding to the folding portion FR, and a first opening pattern 205a in the non-folding portion UFR. Correspondingly, the first layer 200a includes a second opening pattern 205b and a third opening pattern 205c having a density lower than the first density.

The first layer 200a may include at least one of stainless steel (SUS), amorphous metal, amorphous silicon, and Invar. That is, the first layer 200a may be made of any of the listed materials, or some of the listed materials may be laminated, alloyed, or plated.

Stainless steel is formed by improving the corrosion resistance of iron and alloying iron with chromium, etc., and is largely divided into iron-chromium-based ferritic stainless steel and iron-nickel-chromium-based austenitic stainless steel. Stainless steel consists of iron and chromium as its basic ingredients, and nickel may be optionally included depending on the classification of stainless steel. Additionally, the degree of elasticity can be adjusted depending on the chromium content ratio.

In addition, amorphous metals are solidified with an amorphous arrangement of atoms similar to glass or liquid, and are formed when crystal growth is interrupted when metal raw materials are ultra-quickly cooled. These amorphous metals are superior to metals with regular atomic arrangements in terms of corrosion resistance and elasticity.

Additionally, amorphous silicon, which has amorphous properties similar to amorphous metals and has better elasticity than amorphous metals, may be used for the first layer 200a.

Invar is an Fe-Ni alloy that has excellent corrosion resistance and tensile strength. It is compared to stainless steel depending on whether it contains chromium.

When looking at the materials themselves, stainless steel and Invar have high rigidity, and amorphous metal and amorphous silicon can be classified as having high elasticity. However, the degree of internal bonding and rigidity can be adjusted by adjusting the component ratio or cooling rate of the metal alloy included. . Through this, all of the listed materials have relatively higher rigidity than the display panel and can be adjusted to have flexibility according to the folding operation.

In the example shown in FIGS. 2 to 3C, the non-folding portion (UFR) is divided into two on one side of the folding portion (FR), and each divided region includes second opening patterns 205b and 205c with different densities. .

In addition, the illustrated example shows that the folding part FR is positioned to divide the center of the first layer 200a in half. This is one embodiment, and the position of the folding part FR can be changed according to device requirements. And, as shown, it may be set along one side of the display panel 100 and the back plate 200, or may be set along a diagonal direction.

In the flexible display of the present invention, what is significant is that the non-folding portion (UFR) also has opening patterns 205b and 205c, and the density of the opening patterns decreases as the distance from the folding portion FR increases.

The point of having the first opening pattern 205a on the back plate 200 corresponding to the folding portion FR partially divides the area where the folding operation is performed and contraction and expansion are repeated to perform the folding operation stably. This is to reduce the contact area with the display panel 100 facing the display panel 100, thus alleviating the impact on the relatively soft side of the display panel 100 during the folding operation.

In addition, the reason for providing the second and third opening patterns 205b and 205c with different densities for each region (UFR-1 and UFR-2) on the back plate 200 corresponding to the non-folding portion (UFR) is , when the folding portion (FR) with a large opening pattern density is provided only in a certain area of the back plate 200 for interlocking operation with the display panel 100 when folded, there is a large difference in density from the remaining portion, so the folding portion (FR) This is to prevent the boundary between the FR) and the non-folding portion (UFR) from being recognized. In addition, this is to prevent a phenomenon in which the folding portion FR, whose specific gravity is reduced due to the high density of the opening pattern, being relatively saggy, occurs.

For reference, a high density of the opening pattern means that a lot of empty space is distributed in the corresponding area of the back plate 200, and the remaining proportion of the first layer 200a itself is reduced. Conversely, a low density of the opening pattern means that there is little empty space in the first layer 200a, so the first layer 200a occupies a large proportion.

And, as shown in FIGS. 3A to 3C, the back plate 200 further includes a skin layer 210 on at least one side of the first layer 200a to form the blanks of the opening patterns 205a, 205b, and 205c. Additional anti-visibility functions can be added by filling the space.

The skin layer 210 is made of a relatively soft material, such as resin, than the first layer 200a, which is the central layer of the back plate 200. When forming the skin layer 210, the skin layer forming material is used. The opening patterns 205a, 205b, and 205c may be filled.

In the illustrated example, the back plate 200 has a folding portion (FR) in the center, and the non-folding portion (UFR) has two regions (B-1, B-2) on one side of the folding portion (FR) and on the other side. ) indicates the state of being divided.

The illustrated flexible display has a folding portion (FR) in a half position in the center of the back plate 200, and for symmetry, the non-folding portion (UFR) located on one side of the folding portion (FR) and the other side have the same shape. and the same number of areas are located.

In the flexible display of the present invention, a difference in visual perception from other areas is generated by the first opening pattern 200a formed at a high first density in the folding part FR, and the boundary between the folding part FR and the non-folding part UFR is generated. In order to prevent this from being visible, the opening patterns are arranged at a density lower than the first density not only in the folding portion (FR) but also in the non-folding portion (UFR).

Here, the area that can be divided in the non-folding portion (UFR) may change depending on the size of the backplate 200. The larger the flexible display area, the more divided areas the non-folding portion (UFR) can be.

Also, it is preferable that there are two or more divided areas in one non-folding portion (UFR). This is because the stress on the back plate 200 can be distributed and a specific area can be prevented from being visible due to a noticeable difference in the density of the opening pattern.

As the distance from the folding portion FR increases, the density of the opening pattern decreases. As shown, the density of the opening pattern has a fixed density according to each region (FR, UFR-1, UFR-2), and the folding portion (FR), the first non-folding portion (UFR-1), and the second non-folding portion It can be reduced step by step in the order of the folding part (UFR-2), or the density of the opening pattern can be linearly increased as the distance from the folding part (FR) increases in the entire non-folding part (UFR), excluding the folding part (FR). It can also be reduced.

Hereinafter, we will look at the amount of stress and deformation in each region of the backplate of the flexible display of the present invention according to the density of the opening pattern in each region.

FIGS. 4A and 4B are simulation diagrams showing the density and rigidity of the pattern for each region of FIG. 2.

When the backplate of FIG. 2 is cut vertically, the density of the opening pattern appears as shown in FIG. 4A. The opening pattern is densest at the center of the back plate 200, that is, at the folding portion, and in the non-folding portion, the density of the opening pattern gradually decreases as the distance from the folding portion increases. In this case, the stress received at the folding portion (FR) of the back plate 200 was equivalent to 26.76 MPa, resulting in a decrease in the stress value compared to the case where the opening pattern was located only at the folding portion (FR).

In addition, when the backplate of the flexible display of the present invention was unfolded again after a plurality of folding operations, looking at the amount of deformation of the backplate, it was confirmed that there was a displacement of 3.75 mm, as shown in FIG. 4B.

Hereinafter, compared to the flexible display of the present invention, we will look at a comparative example having a back plate selectively provided with an opening pattern in the folding portion.

Figure 5 is a plan view showing a backplate according to a comparative example, and Figures 6a and 6b are simulation diagrams showing the density and rigidity of the pattern for each region of the backplate according to a comparative example.

As shown in FIG. 5 , the backplate 20 according to the comparative example is provided with an opening pattern 25 selectively only in the folding portion FR. The backplate 20 according to the comparative example consists only of the first layer 20a including the opening pattern 25 only in the folding portion FR.

As shown in Figure 6a, the stress received at the folding portion (FR) of the back plate 20 is equivalent to 39.47 MPa, resulting in a stress equivalent to 1.485 times the stress received by the back plate of the present invention shown in Figure 4a. Confirmed.

When the backplate of the comparative example was unfolded again after a plurality of folding operations, the amount of deformation of the backplate was examined, and it was confirmed that the backplate had a displacement of 5.64 mm, as shown in FIG. 6B.

In the comparative example, the density of the opening pattern 25 was set to be the same as the density of the opening pattern 205a of the folding part FR of the present invention.

That is, as shown in FIGS. 6A and 6B, the stress experienced by the folding portion of the back plate of the comparative example is 39.74 MPa, which is 1.485 times that of the back plate of the present invention, and the displacement is 5.64 mm, which is 39.74 MPa, which is 1.485 times that of the back plate of the present invention. This corresponds to 1.504 times the comparison. In other words, if you focus on a specific area of the opening pattern, stress is concentrated in that specific area, which means that deformation of the backplate can be directly visible.

7A and 7B are simulation diagrams showing the flatness between the backplate of the comparative example and the present invention.

In FIGS. 7A and 7B, in common, the point where flatness is maintained is the point where the coordinates of the vertical axis are 0, and when it has a value different from 0, it means that flatness is not maintained.

As shown in FIG. 7A, in the backplate of the comparative example, areas where flatness cannot be maintained due to differences in rigidity between the folded portion and the non-folded portion appear at the boundary between the folded portion and the non-folded portion and at the folded portion.

On the other hand, the backplate of the present invention has a difference in the density of the opening patterns, as shown in Figure 7b, and is provided with opening patterns in both the folding portion (FR) and the non-folding portion (UFR), so that almost flatness is maintained in the entire area. can confirm.

Figure 8 is a photograph corresponding to the first area of the backplate of the present invention.

As shown in FIGS. 3A to 3C, the backplate 200 of the present invention has at least one surface of the first layer 200a in addition to the opening patterns 205a, 205b, and 205c of the first layer 200a with different density differences for each region. A skin layer 210 is provided.

The skin layer 210 is made of a resin material and has a flat surface, and as shown in FIG. 8, it can fill the opening patterns 205a, 205b, and 205c in the first layer 200a, thereby forming the first layer 200a. By reducing the significant difference in density between the remaining portion and the remaining portion, the problem of the opening patterns 205a, 205b, and 205c being visible from the outside can be prevented, and a skin layer 210 with a flat upper surface is provided.

9A to 9C are plan views showing various embodiments of the backplate of the present invention.

In another embodiment of the present invention, as shown in FIG. 9A, the back plate 200 is configured such that the first layer 300a is divided only into a folded portion (FR) and a non-folded portion (UFR) and the opening patterns 305a and 305b are folded. It can be distinguished only by the first density of the portion (FR) and the second density of the non-folded portion. In this case as well, the first density of the folding portion (FR) is greater than the second density of the non-folding portion, and the opening pattern 305a of the folding portion (FR) is arranged more densely than the opening pattern 305b of the non-folding portion (UFR). It can be.

Figure 9b shows another embodiment of the present invention, in the first layer 300a of the back plate 200, the non-folding portion (UFR) has three regions (UFR-1) on one side and the other side of the folding portion (FR), respectively. , UFR-2, and UFR-3), and the opening patterns 315a, 315b, 315c, and 315d are arranged sequentially with their density reduced from the folding portion FR.

Figure 9c shows another embodiment of the present invention, in the first layer 300a of the back plate 200, the folding portion FR has an opening pattern 325a distributed at a first density, and the non-folding portion UFR ) The opening pattern 325b is distributed similarly to the first density adjacent to the folding part FR, and gradually becomes gradated as it moves away from the folding part FR, and has a lower density as it moves away from the folding part FR. It is placed.

In all of the above-described configurations, the backplate 200 is provided with opening patterns with different densities in the folding portion (FR) and the non-folding portion (UFR), and the backplate ensures flexibility in the folding operation of the folding portion (FR). In addition, it is significant in that it can reduce the difference in rigidity between the folding portion and the non-folding portion and prevent the boundary portion from being recognized.

Meanwhile, in other embodiments, as previously described in FIGS. 3A to 3C, a skin layer (not shown, see 210 in FIGS. 3A to 3C) is provided on one side of the first layer 300a, so that the skin layer The forming resin material may fill empty spaces of the opening patterns 305a, 305b/315a, 315b, 315c, 315d/325a, 325b in the first layer 300a.

The flexible display of the present invention described above is provided with an opening pattern in the folding part, and the opening pattern in the non-folding part is provided with a difference in density in a sequential or gradated manner, thereby reducing the difference in stiffness between regions of the back plate to prevent sagging of a specific part. Shape imbalance can be prevented.

Additionally, by providing an opening pattern with different specific gravity in the folded portion and the non-folded portion on the back plate that supports the display panel, the back plate can also be folded in accordance with the folding operation of the display panel, and at the same time, when unfolded, the back plate can be non-folded. It is possible to prevent pattern deviation between the part and the folding part from being recognized.

In addition, a skin layer having lower rigidity than the backplate main body is provided on the surface of the backplate, and the material of the skin layer fills the opening pattern, thereby preventing the opening pattern from being visible due to empty space.

*Electronic device including flexible display according to second embodiment*

FIG. 10 is a cross-sectional view showing an electronic device including a flexible display according to a second embodiment of the present invention, and FIG. 11 is a cross-sectional view showing the backplate of FIG. 10.

10 and 11, an electronic device including a flexible display according to a second embodiment of the present invention includes a display panel 100, a back plate 4000 supporting the display panel 100 from the bottom, and a back panel 100. It includes a first adhesive layer 190 that bonds the plates 4000 together.

For example, the first adhesive layer 190 may be mainly made of thermosetting resin such as epoxy resin, silicone resin, polyester resin, polyurethane resin, or phenolic resin, or may be made of pressure-sensitive adhesive. Thermosetting resin is generally in a liquid form and is applied to either the display panel 100 or the back plate 4000 to bond the two objects together, and then hardens by applying a predetermined amount of heat to form the first adhesive layer 190 in a solidified state. do. The pressure-sensitive adhesive has adhesive properties on both sides. After attaching one side of the pressure-sensitive adhesive to one side of the display panel 100 and the backplate 4000, the other side of the adhesive is attached to the display panel 100 and the backplate 4000. ), the display panel 100 and the back plate 4000 are bonded to both sides of the pressure-sensitive adhesive using the self-weight of the display panel 100 or additional pressure.

Although not shown, the case 400 of FIG. 1 is provided on the side and bottom of the flexible display to accommodate the flexible display formed by bonding the display panel 100 and the back plate 4000 by the first adhesive layer 190. More may be provided. That is, the case may be located on the side of the display panel 100 and the back plate 4000 and below the back plate 4000.

Meanwhile, the back plate 4000 includes, in order from the bottom, a first rigid support part 4100 having a first opening pattern 405 with respect to the folding part FR, and a second adhesive layer located on the support part 4100 ( 420) and a skin layer 430 on the second adhesive layer 420.

The support portion 4100 includes a first layer 410a and a first opening pattern 405 between the first layers 410a. The first opening pattern 405 is an area without the first layer 410a, and the support portion 4100 is formed on the first layer 410a by removing the area of the first opening pattern 405 patterned from the first layer material. It applies.

The first layer 410a has enough rigidity to support the display panel 100 located on the top, and is made of a material with higher rigidity than the display panel 100, such as stainless steel, amorphous metal, and amorphous material. It may include at least one of silicon and invar.

In the electronic device according to the second embodiment, the main feature is a skin layer 430 on top of the first layer 410 made of a material similar to the first layer 410 and having a higher elastic recovery force than the first layer 410. ) and a second adhesive layer 420 is further provided between the first layer 410 and the skin layer 430. In the above-described first embodiment, a resin material was used, but in the second embodiment, the skin layer 430 is made of at least one of stainless steel, amorphous metal, and Invar, which has a higher elastic recovery force than the first layer 410. It includes, and is formed of alloy or inorganic material. In the stacked structure of the backplate 4000, the skin layer 430 and the first layer 410 are positioned above and below with the second adhesive layer 420 interposed therebetween.

The first layer 410 and the skin layer 430 are formed of the same type of alloy or inorganic material, and the elastic recovery can be adjusted by varying the alloy component ratio, or the elastic recovery can be adjusted by varying the thickness. Alternatively, the first layer 410 and the skin layer 430 may be selected from materials having different elastic recovery properties. For example, the first layer 410 may be formed of stainless steel or invar, and the skin layer 430 may be formed of amorphous metal or amorphous silicon.

The skin layer 430 is further provided to further protect the folding portion FR in the electronic device, thereby preventing visibility or cracking of the folding portion FR when touched by a hand or a pen. . Therefore, reliability can be improved in operations such as touch.

Although not shown in FIGS. 10 and 11, as described in the first embodiment, the non-folding portion (UFR) also has a second opening pattern (not shown) at a lower density than the first opening pattern 405a of the folding portion (FR). ) may be further provided. The second opening pattern is intended to prevent the first opening pattern 405a from being prominently visible.

The skin layer 430 is provided to increase the ductility of the back plate 4000 and is formed to be thinner than the first layer 410a. Approximately, the first layer 410a is formed to have a thickness of 30 ㎛ to 200 ㎛, and the skin layer 430 is formed to have a thickness of 10 ㎛ to 50 ㎛. The second adhesive layer 420 provided in between is formed close to or thinner than the skin layer 430, and can be formed with a thickness of 5㎛ to 20㎛.

The second adhesive layer 420 can be mainly formed of thermosetting resin, such as epoxy resin, silicone resin, polyester resin, polyurethane resin, and phenol resin.

Hereinafter, a method for manufacturing a backplate of an electronic device according to a second embodiment of the present invention will be described.

FIGS. 12A to 12C are cross-sectional process views showing a method of manufacturing the backplate of FIG. 11.

As shown in FIG. 12A, after forming the second adhesive layer 420 on the first layer material 410, a skin layer 430 is formed on the second adhesive layer 420, thereby forming the second adhesive layer 420. The skin layer 430 and the first layer material 410 are attached top and bottom to form a thin layer (lamination).

Next, as shown in FIG. 12B, a photoresist pattern 440 is formed on the surface of the unadhered first layer material 410, excluding the area where the first opening pattern is to be formed (and the second opening pattern).

The exposed first layer material 410 is etched by applying an etchant to the area exposed by the photoresist pattern 440 to form a first opening pattern 405 (and a second opening pattern (not shown)) as shown in FIG. 12C. ) to form a first layer 410a having it inside. When forming the second opening pattern, the density is lower than that of the first opening pattern 405 , so the distance between the second opening patterns may be longer than that of the first opening pattern 405 .

Next, the photosensitive film pattern 440 may be removed to form a backplate 4000 in which the first opening pattern 405 is selectively formed only on the first layer 410a in a layered structure. After completing the process, the second adhesive layer 420 and skin layer 430 maintain their thickness.

In the above-described process, in the thinning process of FIG. 12A, the second adhesive layer 420 may be thermally cured, and accordingly, the second adhesive layer 420 may be solidified before the etching process of the first layer material 410. As is, the thickness is almost maintained, and as shown in Figure 12c, the second adhesive layer 420 can be exposed and observed through the first opening pattern 405 even after the etching process of the first layer material 410. Additionally, in the first opening pattern 405 between the second adhesive layer 420 and the surface of the first layer 410a that is not in contact with the second adhesive layer 420, the first layer ( 410a) It may have a space (s) less than or equal to the thickness. In FIG. 12C, the space s is shown to have the thickness of the first layer 410a, but this is not limiting, and a part of the second adhesive layer 420 enters the first opening pattern 405 to form the first layer ( It may have a space (s) with a thickness lower than that of 410a).

Hereinafter, the first layer in the backplate completed with the first opening pattern 405 is collectively referred to as 410a.

In detail, examples will be examined according to the shape of the opening pattern formed in the first layer.

FIG. 13A is a plan view showing the folding portion of the back plate of FIG. 11 and its surroundings according to an embodiment, and FIG. 13B is an enlarged perspective view of FIG. 13A.

In the backplate according to FIGS. 13A and 13B, the first opening pattern 405 is disposed in a plurality of columns within the layer of the first layer 410a, with a discontinuity DC between each column. It has a support portion 4100 in the form of a plurality of divisions. In this case, the first opening patterns 405 are not parallel in adjacent rows. That is, the first opening patterns 405 in even rows are shifted by a distance smaller than the length of each first opening pattern 405 in the longitudinal direction of the first opening patterns 405 with respect to the first opening patterns 405 in odd rows. You can. This is to distribute force when stress is applied during folding. At this time, the discontinuity DC1 between the first opening patterns 405 in odd columns and the discontinuity DC2 between the first opening patterns 405 in even columns are located in different rows. The discontinuities DC1 and DC2 are integrated with the first layer 410a.

The longitudinal direction in which the first opening pattern 405 is formed may be a folding direction or a direction perpendicular to the folding direction.

In addition, as shown in FIG. 13A, the non-folding portion on both sides of the edge portion E of the folding portion FR is not provided with an opening pattern, and the area maintaining the thickness of the first layer 410a has a certain width. It can be provided. This is to recover the rigidity lost due to the continuation of the opening pattern in the first layer around the folding portion (FR). There are unformed portions of the opening pattern of a certain width on both sides of the edge portion (E) of the folding portion (FR), and again, as shown in FIG. 9B, a second opening pattern (315b, etc.) having a lower density than the first opening pattern (315a). The opening pattern may be further provided on one side of the unformed portion.

The first opening pattern 405 may be repeatedly arranged by pairing two adjacent columns.

The first opening pattern 405 provided in the folding portion FR allows the hard support portion 4100 to have flexibility and operate flexibly like a spring according to the folding operation, thereby reducing stress due to contraction and tension during folding. It will be easy to restore it to its original state without receiving it.

FIG. 14A is a plan view showing the folding portion of the back plate of FIG. 11 and its surroundings according to another embodiment, and FIG. 14B is an enlarged perspective view of FIG. 14A.

The backplate according to FIGS. 14A and 14B includes a plurality of first opening patterns 505 in the folding portion FR within the layer of the first layer 510a, each of which has a support portion ( 510).

The first opening pattern 505 according to FIGS. 13A and 13B described above is formed close to a mesh type, and the first opening pattern 505 according to FIGS. 14A and 14B is formed in a straight type. At this time, the longitudinal direction of the first opening pattern 505 may be a folding direction or a direction perpendicular to the folding direction.

Such a stripe-type opening pattern may be further provided in the non-folding portion at a density smaller than that of the first opening pattern. In the folding part, the hard support part 510 has flexibility according to the folding operation and operates flexibly like a spring, so that it is easy to return to the original state without stress from contraction or tension during folding.

In the backplate of the electronic device according to the above-described second embodiment, the skin layer opposing the first layer of the backplate with the adhesive layer in between is made of an alloy layer or an inorganic material of amorphous silicon with better elastic recovery than the first layer. This ensures ductility and at the same time maintains a flat shape of the skin layer by solidifying the adhesive layer before forming (etching) the opening pattern, thereby preventing the display panel from cracking due to external forces during use such as touch.

Hereinafter, a display panel of a flexible display commonly used in the electronic device of the present invention will be described.

Figure 15 is a cross-sectional view showing the display panel 100 of the flexible display of the present invention.

As shown in FIG. 15, a buffer layer 120 is formed on a flexible substrate (flexible base substrate 112), and a thin film transistor (Tr) is formed on the buffer layer 120. The buffer layer 120 may be omitted.

A semiconductor layer 122 is formed on the buffer layer 120. The semiconductor layer 122 may be made of an oxide semiconductor material or polycrystalline silicon.

When the semiconductor layer 122 is made of an oxide semiconductor material, a light blocking pattern (not shown) may be formed on the lower part of the semiconductor layer 122, and the light blocking pattern prevents light from entering the semiconductor layer 122. This prevents the semiconductor layer 122 from being deteriorated by light. Alternatively, the semiconductor layer 122 may be made of polycrystalline silicon, and in this case, both edges of the semiconductor layer 122 may be doped with impurities.

A gate insulating film 124 made of an insulating material is formed on the semiconductor layer 122. The gate insulating film 124 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 130 made of a conductive material such as metal is formed on the gate insulating film 124 corresponding to the center of the semiconductor layer 122.

In FIG. 16 , the gate insulating film 124 is formed on the entire surface of the flexible base substrate 112, but the gate insulating film 124 may be patterned to have the same shape as the gate electrode 130.

An interlayer insulating film 132 made of an insulating material is formed on the gate electrode 130. The interlayer insulating film 132 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating film 132 has first and second contact holes 134 and 136 exposing both sides of the semiconductor layer 122. The first and second contact holes 134 and 136 are located on both sides of the gate electrode 130 and are spaced apart from the gate electrode 130 .

Here, the first and second contact holes 134 and 136 are also formed within the gate insulating film 124. Alternatively, when the gate insulating layer 124 is patterned to have the same shape as the gate electrode 130, the first and second contact holes 134 and 136 may be formed only within the interlayer insulating layer 132.

A source electrode 140 and a drain electrode 142 made of a conductive material such as metal are formed on the interlayer insulating film 132.

The source electrode 140 and the drain electrode 142 are positioned spaced apart from each other around the gate electrode 130, and are provided on both sides of the semiconductor layer 122 through the first and second contact holes 134 and 136, respectively. come into contact with

The semiconductor layer 122, the gate electrode 130, the source electrode 140, and the drain electrode 142 form the thin film transistor (Tr), and the thin film transistor (Tr) is a driving element. It functions as

The thin film transistor (Tr) may have a coplanar structure in which the gate electrode 130, the source electrode 142, and the drain electrode 144 are located on top of the semiconductor layer 120.

In contrast, the thin film transistor (Tr) may have an inverted staggered structure in which the gate electrode is located at the bottom of the semiconductor layer and the source electrode and drain electrode are located at the top of the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Although not shown, gate wires and data wires intersect each other to define a pixel area, and a switching element connected to the gate wire and data wire is further formed. The switching element is connected to a thin film transistor (Tr), which is a driving element.

In addition, a power wire is formed parallel to and spaced apart from the data wire or the data wire, and a storage capacitor is further provided to keep the voltage of the gate electrode of the thin film transistor (Tr), which is a driving element, constant during one frame. It can be configured.

A protective layer 145 having a drain contact hole 152 exposing the drain electrode 142 of the thin film transistor Tr is formed to cover the thin film transistor Tr. Thin film transistors (Tr) of the same shape are provided in each pixel area, and, including all thin film transistors (Tr) included on the flexible base substrate 112, are called a thin film transistor array.

On the protective layer 145, a first electrode 160 connected to the drain electrode 142 of the thin film transistor (Tr) through the drain contact hole 152 is formed separately for each pixel area. The first electrode 160 may be an anode and may be made of a conductive material with a relatively high work function value. For example, the first electrode 160 is made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO), or such transparent conductive material. It may be made of multiple layers of electrodes including at least one layer of material.

Meanwhile, when the display panel 100 of the present invention is a top-emission type, a reflective electrode or a reflective layer may be further formed below the first electrode 160. For example, the reflective electrode or the reflective layer may be made of aluminum-palladium-copper (APC) alloy. In some cases, a transparent conductive material may be further included under the reflective electrode.

Additionally, a bank layer 166 is formed on the protective layer 145 to cover the edge of the first electrode 160. The bank layer 166 exposes the center of the first electrode 160 corresponding to the pixel area.

An organic light-emitting layer 162 is formed on the first electrode 160. The organic light-emitting layer 162 may have a single-layer structure of an emitting material layer made of a light-emitting material. In addition, in order to increase light emission efficiency, the organic light emitting layer 162 includes a hole injection layer, a hole transport layer, a light emitting material layer, and an electron transport layer sequentially stacked on the first electrode 160. It may have a multi-layer structure of an electron transporting layer and an electron injection layer.

A second electrode 164 is formed on the flexible base substrate 112 on which the organic light emitting layer 162 is formed. The second electrode 164 is located in front of the display area and is made of a conductive material with a relatively low work function value and can be used as a cathode. For example, the second electrode 164 may be made of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg).

The first electrode 160, the organic light emitting layer 162, and the second electrode 164 form an organic light emitting diode (D). The organic light emitting diode (D) is provided in connection with a thin film transistor (Tr) in each pixel area, and organic light emitting diodes formed in the entire pixel area are also collectively referred to as organic light emitting diodes.

An encapsulation film 170 is formed on the second electrode 164 to prevent external moisture from penetrating into the organic light emitting diode (D). The encapsulation film 170 may have a stacked structure of a first inorganic insulating layer 172, an organic insulating layer 174, and a second inorganic insulating layer 176, but is not limited to this and may include an inorganic insulating layer and It is composed of alternating organic insulating layers, with the inorganic insulating layer located on the outermost side.

Additionally, a touch electrode array including first touch electrodes 181 and second touch electrodes 182 that cross each other for touch detection may be further provided on the encapsulation film 170. The illustrated form includes a bridge wiring 181a on the outermost second inorganic insulating layer 176, a touch insulating film 183 on top of the bridge wiring 181a, and the touch insulating film 183. ) is provided with a first touch pattern 181b and a second touch electrode 182 spaced apart from each other. Here, the first touch pattern 181b is electrically connected to the bridge wire 181a through a contact hole in the touch insulating layer 183 to form the first touch electrode 181. The second touch electrode 182 in the drawing only shows a portion. The second touch electrode 182 is located on the touch insulating film 183 where the first touch pattern 181b is not located, and is spaced apart from the first touch electrode 182. A mutual capacitance (Cm) is generated between the second touch pattern 181b and the second touch pattern 181b.

Additionally, a touch may be detected through a change in mutual capacitance (Cm) depending on whether or not the touch is touched.

The illustrated touch electrode array is an example and is not limited thereto. As shown, the touch electrode array may be formed directly on the encapsulation film 170, or may be further provided with a separate substrate or insulating film. And, a touch electrode array may be provided on top of the cover film, or a touch electrode array may be provided inside the cover film. In some cases, it may be considered that the touch electrode array is not provided or that the upper part of the display panel 100 is located with the encapsulation film 170.

Additionally, a polarizer (not shown) may be attached to the top of the touch electrode array to reduce external light reflection. For example, the polarizer may be a circular polarizer. Alternatively, a cover layer such as a cover window may be further provided to protect the upper part of the touch electrode array.

Meanwhile, '1100', which is not described, refers to an array of thin film transistors (Tr) formed on the flexible base material 112, an array of organic light emitting diodes (D) connected to each thin film transistor (Tr), and an encapsule covering them. It refers to an array structure that includes both a lation film 170 and a touch electrode array 181, 182, and 183.

Meanwhile, the above-mentioned display panel is an organic light emitting display panel as an example, and can be changed to other types of display panels if flexible. For example, a flexible liquid crystal panel, quantum dot display panel, electrophoretic display panel, etc. may replace the organic light emitting display panel described above.

In the above, specific embodiments have been described with reference to the drawings to illustrate the technical idea of the present invention. However, the present invention is not limited to the same configuration and effect as the specific embodiments as described above, and various modified examples are within the scope of the present invention. It can be implemented within the limits of . Therefore, such modifications should also be considered to fall within the scope of the present invention, and the true technical protection scope of the present invention should be determined by the technical spirit of the patent claims described later.

100: display panel 200: backplate
200a: first layer 205a, 205b, 205c: opening pattern
210: skin layer 400: case

Claims (20)

display panel; and
It is divided into a folding part and a non-folding part, a first layer of a material having higher rigidity than the display panel, a first opening pattern corresponding to the folding part and having a first density in the first layer, and the non-folding part a back plate including a second opening pattern corresponding to the first layer and having a second density lower than the first density,
The second density gradually decreases in the non-folding portion as the distance from the folding portion increases. According to clause 1,
The non-folding portion is divided into two or more regions,
A flexible display including a backplate where one area has a second opening pattern of the second density, and the remaining area has a third opening pattern of a density different from the first and second densities. According to clause 2,
A flexible display in which the density of the second and third opening patterns in the non-folding part becomes lower as the distance from the folding part increases. According to clause 1,
The first density is a fixed flexible display in the folding unit. According to clause 1,
The first layer is a flexible display comprising at least one of stainless steel, amorphous metal, amorphous silicon, and Invar. According to clause 1,
The back plate is a flexible display further comprising a skin layer on at least one side of the first layer. According to clause 1,
A flexible display further comprising a first adhesive layer between the display panel and the backplate. According to clause 6,
A flexible display in which the skin layer is made of resin. According to claim 8,
A flexible display in which the resin is filled in the first and second opening patterns. According to clause 6,
The backplate is
A flexible display further comprising a second adhesive layer between the first layer and the skin layer. According to clause 10,
A flexible display wherein the skin layer is made of a material with higher elastic recovery than the first layer. According to clause 11,
A flexible display wherein the skin layer includes at least one of stainless steel, amorphous metal, amorphous silicon, and Invar. According to clause 10,
A flexible display in which the second adhesive layer is exposed through the first and second opening patterns. According to clause 10,
A flexible display having a space less than or equal to the thickness of the first layer in the first and second opening patterns between the second adhesive layer and a surface of the first layer that is not in contact with the second adhesive layer. According to clause 1,
A flexible display wherein the first opening pattern is plural in the folding part, and each of the first opening patterns is formed to be long in one direction. According to clause 1,
The first opening pattern is arranged in a plurality of columns, and each column is divided into a plurality of pieces with a discontinuity therebetween. According to clause 16,
The first opening pattern is a flexible display in which discontinuities are located in different rows in adjacent columns. According to clause 11,
The skin layer is a flexible display whose thickness is thinner than the first layer. According to clause 10,
A flexible display further including a region of a predetermined width in which the first and second opening patterns are not provided at a boundary portion of the folding portion in the first layer. A flexible display according to any one of claims 1 to 19; and
An electronic device including a case storing the display panel and back plate.