KR20190060190A - Foldable display device - Google Patents

Abstract

The present invention relates to a foldable display device with a dual function spacer in a folding area. According to the present invention, the foldable display device comprises: a substrate having a folding area with a folding axis and a non-folding area; a bank layer covering part of the outer periphery of an electrode electrically connected to a thin film transistor positioned on the substrate; a first spacer positioned on the bank layer, having a first width and a second width longer than the first width, and positioned in the non-folding area; and a second spacer positioned in the folding area on the bank layer and having a third width having a longer length in a direction extending so that the second width intersects the extended direction and a fourth width shorter than the third width wherein a crack is suppressed in the second spacer.

Description

FOLDABLE DISPLAY DEVICE}

The present invention relates to a foldable display device having a dual function spacer in a folding region.

The image display device that realizes various information on the screen is a core technology of the information communication age. It is a cathode ray tube display panel, a liquid crystal display panel, an electrophoretic display panel, And an organic light emitting display panel.

In particular, organic light emitting display panels for displaying images by controlling the amount of light emitted from organic light emitting elements are being popularized in order to realize thinner, lighter, portable and high-performance image display devices.

Since the organic light emitting display panel is a self light emitting display panel and is implemented without a separate light source device, it can be manufactured in a light and thin form. Further, the organic light emitting display panel is easily realized as a foldable display device by disposing the thin film transistor and the organic light emitting layer on a foldable substrate.

The organic light emitting display panel implemented by the display device of the present invention may be vulnerable to an external impact. Particularly, when the display device of a foldable display is folded, the organic luminescent layer is weak in adhesive force, and peeling of the organic luminescent layer may occur in the vicinity of the folding area and may be broken.

Therefore, the organic light emitting display panel can protect the organic light emitting layer by preventing the peeling of the organic light emitting layer from external impact caused by folding of the display device by positioning the spacer in the non-light emitting region.

At this time, when the display device is folded, folding stress (or stress) may be applied to the organic light emitting display panel by folding. If the stress is continuously applied by repeated folding, the spacer provided in the organic light emitting display panel may be broken. Therefore, the broken spacer may become a foreign object, which may cause a dark spot in the organic light emitting layer. The dark point of the organic light emitting layer can reduce the brightness of the display device.

Accordingly, the inventors of the present invention have recognized the need to minimize the folding stress experienced by the spacer in order to realize a foldable display device. Therefore, the inventors of the present invention have devised a new structure in which the organic light emitting display panel of the display device of the present invention is provided with a spacer but the breakage of the spacer is suppressed.

The problems of the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A foldable display device according to an embodiment of the present invention includes a substrate having a folding region having a folding axis and a folding region, a bank layer covering a part of an outer portion of the electrode electrically connected to the thin film transistor located on the substrate, A first spacer located on the layer and having a second width greater than the length of the first width and located in the folded region on the first spacer and bank layer located in the unfolded region, And a second spacer with a crack-suppressed second spacer having a third longer width in a direction extending in an extended direction and a fourth width shorter than the third width.

The second spacers are arranged in a stretched minimized arrangement structure such that the substrate is folded with respect to the folding axis.

The stretching minimized arrangement structure is a structure in which the fourth spacer is orthogonal to the folding axis so that the stretching in the longitudinal direction of the fourth width is minimized.

The stretching minimized arrangement structure is a structure in which the second spacer is parallel to the folding axis so that the stretching in the longitudinal direction of the third width is minimized.

The length of the third width of the second spacer is equal to the length of the second width and the length of the fourth width of the second spacer is equal to the length of the first width.

The length of the third width of the second spacer is longer than the length of the first width and shorter than the length of the second width and the length of the fourth width of the second spacer is longer than the length of the first width, .

According to another aspect of the present invention, there is provided a display device including a substrate composed of a folding region and an unfolded region, a thin film transistor located on the substrate, a first insulating layer covering the thin film transistor, An electrode electrically connected to the thin film transistor through a contact hole; a second insulating layer located on the first insulating layer and covering a portion of the electrode and the contact hole. And a dual function spacer located on the second insulating layer in the organic light emitting layer and the folding region located on the electrode and capable of improving folding easiness and luminance reduction.

The dual function of the dual function spacer is realized by suppressing the breakage of the dual function spacer with a structure in which the folding stress is minimized.

The structure in which the folding stress is minimized is configured such that the length of the specific width of the dual function spacer is the shortest of the remaining width in the same direction as the direction in which the substrate is stretched.

The dual function spacer is configured to have the longest length of another width perpendicular to the specified width.

The dual function spacer has the same shape as the spacer disposed in the unfolding region.

The dual function spacer has a trapezoidal shape when viewed from one side of the display device.

The size of the largest base of the dual function spacer is larger than the size of the largest base of the spacer disposed in the unfolding region.

The dual function spacer has a structure in which the reflection inside the panel is minimized, thereby improving the efficiency of suppressing the luminance reduction.

The structure in which the reflection inside the panel is minimized is a structure in which a part of the dual function spacer is placed on the contact hole and overlapped to shield it.

The present invention has a dual function spacer, which is a structure that minimizes folding stress in the folding area, so that breakage can be suppressed when the folding display device is folded.

According to the present invention, the double function spacer is provided in the folding area, so that the foldability of the display device can be improved.

The present invention is equipped with a dual function spacer in the folding region, and it is possible to suppress the luminance reduction of the foreign substance display apparatus.

The effects according to the embodiments of the present invention are not limited by the contents exemplified above, and a more various effects are included in the specification.

1 is a plan view of a display device according to an embodiment of the present invention.
2A is a cross-sectional view taken along line IIa-IIa 'of FIG.
2B is a cross-sectional view taken along line IIb-IIb 'of FIG.
3 is a plan view showing the arrangement of spacers of a display device according to an embodiment of the present invention.
4 is a plan view showing the arrangement of spacers of a display device according to another embodiment of the present invention.
5 is a plan view showing the arrangement of spacers of a display device according to another embodiment of the present invention.

Brief Description of the Drawings The advantages and features of the present disclosure, and how to accomplish them, will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. Where the terms "comprises", "having", "done", and the like are used in this specification, other portions may be added unless "only" is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise. In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions. An element or layer is referred to as being another element or layer " on ", including both intervening layers or other elements directly on or in between. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening " or that each component may be " connected, " " coupled, " or " connected " through other components.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

Like reference numerals refer to like elements throughout the specification.

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

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, technically various interlocking and driving, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a plan view of a display device according to an embodiment of the present invention. In FIG. 1, only the organic light emitting display panel 110 is shown among various components of the display device 100 for convenience of explanation.

The organic light emitting display panel 110 is a panel in which an image is implemented. An organic light emitting device for implementing an image, a circuit for driving the organic light emitting device, wiring, and components may be disposed.

The OLED display panel 110 includes a display area AA, a non-display area NA, a folding area FA, and a non-folding area NFA.

The display area AA is an area for displaying an image, and a plurality of pixels made up of organic light emitting elements are arrayed. In the display area AA, an organic light emitting element for displaying an image and a circuit part for driving the organic light emitting element may be disposed. For convenience of explanation, it is assumed that the present invention is a foldable display device 100 including an OLED display panel 110 having an organic light emitting device, but the present invention is not limited thereto.

The circuit portion may include various thin film transistors, capacitors, wirings, and the like for driving the organic light emitting element. For example, the circuitry may include, but is not limited to, a drive thin film transistor, a switching thin film transistor, a storage capacitor, a gate wire, a data wire, and the like.

The non-display area NA is an area in which no image is displayed, and is a region in which a circuit, wiring, and parts for driving the organic light emitting elements in the display area AA are arranged. Various ICs and driving circuits, such as a gate driver IC and a data driver IC, may be disposed in the non-display area NA. For example, various ICs and driving circuits may be mounted on a non-display area NA of the organic light emitting display panel 110 using a GIP (Gate In Panel) or a TCP (Tape Carrier Package) or a COF And may be connected to the organic light emitting display panel 110 in a similar manner.

The organic light emitting display panel 110 may also be defined as a display area AA and a non-display area NA, but may be defined as a folding area FA and a folding area FA.

The folding area (or the folding area) FA is a region where the organic light emitting display panel 110 is folded when the display device 100 is folded, (NA). ≪ / RTI > The present invention is described by way of example in which the folding area FA includes a part of the display area AA and a part of the non-display area NA. However, the present invention is not limited to this, There may be a display area NA. Therefore, the folding area FA may include only a part of the display area AA.

The folding area FA can be folded according to a specific radius of curvature with respect to the folding axis (or the folding axis). Specifically, the folding axis may be the X axis. When the folding area FA is folded with respect to the folding axis, the folding area FA may form part of a circle or an ellipse. At this time, the radius of curvature of the folding area FA means the radius of the circle or the ellipse corresponding to a part of the circle or ellipse formed by the folding area FA. In the present invention, the folding axis in the X axis direction is located in the folding area FA and the folding area NFA is extended in the Y axis direction from the folding area FA and perpendicular to the folding axis. But is not limited thereto.

The non-folding area (or non-folded area) NFA is an area where the organic light emitting display panel 110 is not folded when the display device 100 is folded. That is, the folding area NFA is a region where the organic light emitting display panel 110 maintains a flat state when the display device 100 is folded. The non-folding area NFA may include a part of the display area AA and a part of the non-display area NA.

The folding area NFA may be an extended area located on both sides of the folding area FA. That is, the non-folding area NFA may be a region extending in the Y-axis direction with respect to the folding axis. At this time, the folding area FA may be defined between the non-folding areas NFA. Therefore, when the organic light emitting display panel 110 is folded with respect to the folding axis, the folding area NFA may face each other.

Hereinafter, the folder-type display device 100 will be described in more detail with reference to FIGS. 2A and 2B.

2A is a cross-sectional view taken along line IIa-IIa 'of FIG. 2B is a cross-sectional view taken along line IIb-IIb 'of FIG. FIG. 2A is a sectional view of the display device in the Y-axis direction, and FIG. 2B is a sectional view of the display device in the X-axis direction.

The display device 100 according to an embodiment of the present invention shown in FIGS. 2A and 2B is a display device in which light emitted from the organic light emitting device 130 of the organic light emitting display panel 110 is emitted through a cathode Emitting display panel 100 that emits light to the upper portion of the light-emitting display panel 110. The top- However, the present invention is not limited to the top-emission type of the display device 100, but can be applied to a bottom-emission type display device and a dual side-emission type display device .

The substrate 101 supports various components of the display device 100. The substrate 101 is a flexible substrate 101 that is foldable because it can be made of a plastic material having flexibility. At this time, when the substrate 101 is folded with respect to the folding axis, the foldable display device 100 may be folded. For example, in the case where the substrate 101 is made of polyimide (PI), a manufacturing process is performed in a state where a supporting substrate made of glass is disposed under the substrate 101, and after the manufacturing process is completed, release. Further, a back plate for supporting the substrate 101 may be disposed below the substrate 101 after the supporting substrate is released. The substrate 101 that can be applied to the display device 100 of the present invention may be formed of not only a plastic material but also another material having flexibility as long as the display device 100 is a material that does not break even if folding is repeated .

A thin film transistor (120) is disposed on a substrate (101). The thin film transistor 120 includes an active layer 121 made of polysilicon, a gate electrode 124, a source electrode 122, and a drain electrode 123. The thin film transistor 120 is a thin film transistor of a top gate structure in which a gate electrode 124 is disposed on the active layer 121 (120). 2A and 2B show only the driving thin film transistor among various thin film transistors that can be included in the display device 100 for convenience of explanation, other thin film transistors, such as switching thin film transistors, . Although the thin film transistor 120 is described as being a coplanar structure in this specification, the thin film transistor 120 may be implemented with another structure such as a staggered structure. Although the thin film transistor 120 is disposed on the substrate 101 in FIG. 2, the present invention is not limited thereto. For example, the type and the material of the substrate 101, the structure and the type of the thin film transistor 120, A multi-buffer layer may be disposed between the substrate 101 and the thin film transistor 120.

The active layer 121 of the thin film transistor 120 is disposed on the substrate 101. [ The active layer 121 includes a channel region where a channel is formed when the thin film transistor 120 is driven, a source region and a drain region on both sides of the channel region. The channel region, the source region, and the drain region may be defined by ion doping (impurity doping).

The active layer 121 of the thin film transistor 120 may be made of polysilicon. Thus, polysilicon is formed by depositing an amorphous silicon (a-Si) material on the substrate 101, performing a dehydrogenation process, a crystallization process, an activation process, and a hydrogenation process, (121) may be formed. When the active layer 121 is made of polysilicon, the thin film transistor 120 may be an LTPS thin film transistor 120 using low temperature poly-silicon (LTPS). The polysilicon material has a high mobility, and when the active layer 121 is made of polysilicon, it has an advantage of low energy consumption and excellent reliability.

In addition, the active layer 121 of the thin film transistor 120 may be made of an oxide semiconductor material. The active layer 121 of the thin film transistor 120 may be formed of a metal oxide, for example, a metal oxide such as IGZO, but is not limited thereto. Since the oxide semiconductor material has a larger bandgap than the silicon material, the electrons can not go beyond the bandgap in the off state and thus the off-current is low.

A gate insulating layer 102 is disposed on the active layer 121. The gate insulating layer 102 may be composed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) which is an inorganic material or a multilayer of silicon nitride (SiNx) or silicon oxide (SiOx). The source electrode 122 and the drain electrode 123 are provided in the gate insulating layer 102 with contact holes for making contact with the source region and the drain region of the active layer 121, respectively. In FIG. 2, the gate insulating layer 102 is illustrated as being planarized for convenience of explanation. However, the gate insulating layer 102 may be formed along the shape of the components disposed below.

A gate electrode 124 is disposed on the gate insulating layer 102. A metal layer such as molybdenum (Mo) is formed on the gate insulating layer 102, and a gate electrode 124 is formed by patterning the metal layer. The gate electrode 124 is disposed on the gate insulating layer 102 so as to overlap the channel region of the active layer 121.

An interlayer insulating layer 103 is disposed on the gate electrode 124. The interlayer insulating layer 103 may be composed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx) which is an inorganic material or a multilayer of silicon nitride (SiNx) or silicon oxide (SiOx). The source electrode 122 and the drain electrode 123 of the interlayer insulating layer 103 each have a contact hole for making contact with the source region and the drain region of the active layer 121, respectively. In FIGS. 2A and 2B, the interlayer insulating layer 103 is shown as being planarized for convenience of explanation. However, the interlayer insulating layer 103 may be formed along the shape of the components arranged below.

A source electrode 122 and a drain electrode 123 are disposed on the interlayer insulating layer 103. The source electrode 122 and the drain electrode 123 may be formed of a conductive metal material and may have a three-layer structure of, for example, titanium (Ti) / aluminum (Al) / titanium (Ti) Each of the source electrode 122 and the drain electrode 123 may be connected to each of the source region and the drain region of the active layer 121 through a contact hole provided in the gate insulating layer 102 and the interlayer insulating layer 103. [

A planarization layer (or first insulation layer) 105 is disposed on the thin film transistor 120. At this time, the planarization layer 105 may cover and protect the TFT 120. Also, the planarization layer 105 may be planarized over the thin film transistor 120, and the organic light emitting diode 130 may be more reliably formed. At this time, the planarization layer 105 may include a contact hole through which the anode 131 of the organic light emitting diode 130 is connected to the thin film transistor 120.

The organic light emitting device 130 is disposed on the planarization layer 105. The organic light emitting device 130 includes an anode electrode 131 formed on the planarization layer 105 and electrically connected to the source electrode 122 of the thin film transistor 120, an organic emission layer 122 disposed on the anode electrode 131, And a cathode electrode 133 formed on the organic light emitting layer 132. The anode electrode 131 is located on the planarization layer 105 and may be electrically connected to the thin film transistor 120 through a contact hole provided in the planarization layer 105. The anode electrode 131 is formed in the reflective layer for reflecting the light emitted from the organic light emitting layer 132 toward the cathode 133 and the organic light emitting layer 132 for the hole blocking display device 100 And may include a transparent conductive layer for supplying. However, the anode electrode 131 may include only the transparent conductive layer, and the reflective layer may be defined as a separate component from the anode electrode 131.

The organic light emitting layer 132 may include one of a red organic light emitting layer, a green organic light emitting layer, a blue organic light emitting layer, and a white organic light emitting layer as an organic layer for emitting light of a specific color. If the organic light emitting layer 132 includes a white organic light emitting layer, a color filter may be disposed on the organic light emitting device 130 to convert white light from the white organic light emitting layer into light having a different color. The organic light emitting layer 132 may further include various organic layers and / or inorganic layers such as a hole transporting layer, a hole injecting layer, an electron injecting layer, and an electron transporting layer.

The cathode 133 may be made of a transparent conductive material, for example, a transparent conductive oxide such as IZO or ytterbium (Yb).

The sealing portion 140 may be stacked on the cathode 133. [ At this time, the sealing portion 140 may have a structure in which an inorganic layer and an organic layer are alternately stacked. Accordingly, the sealing portion 140 prevents the organic light emitting device 130, which is vulnerable to moisture and / or oxygen, from being exposed to moisture and / or oxygen, so that the organic light emitting device 130 can be protected.

A bank (or a second insulating layer) 107 is disposed on the anode electrode 131 and the planarization layer 105. At this time, the bank 107 is located on the planarization layer 105, and can cover a part of the outer periphery of the anode electrode 131 and the contact hole included in the planarization layer 105. The bank 107 can be positioned adjacent to each of the pixels arranged in the display area AA and can distinguish each of the pixels so that the bank 107 can define each pixel area. The banks 107 may be made of organic materials. For example, the bank 107 may be made of polyimide, acryl or benzocyclobutene (BCB) resin, but is not limited thereto.

A plurality of spacers 150 and 160 are disposed on the bank 107. An array of spacers 150 and 160 may be located between the pixels of the organic light emitting device 130. At this time, the spacers 150 and 160 may be positioned adjacent to the organic light emitting layer 132. The spacers 150 and 160 can protect the organic light emitting layer 132 from external impacts when the display device 100 is folded. Therefore, the spacers 150 and 160 can prevent lifting due to the weak adhesive force of the organic light emitting layer 132. Accordingly, the spacers 150 and 160 can prevent the organic light emitting layer 132 from peeling off.

At least some of the spacers 160 in the folding area FA of the spacers 150 and 160 may be structurally different from at least some of the spacers 150 in the non-folding area NFA. At this time, the dual function spacer 160 may be disposed in the folding area FA. The dual function spacer 160 can make it easier to fold the display device 100 and to suppress luminance reduction.

As shown in Fig. 2A, when the foldable display device 100 is folded, the substrate 101 can be folded with a specific radius of curvature. At least one feature of the shape, number, position, density, and area characteristics of the dual function spacer 160 disposed in the folding area FA is a characteristic of the flexible substrate 101 in the folding area FA. Can be determined according to the folding radius of curvature.

Specifically, the spacers 150 disposed in the non-folding area NFA and the dual function spacers 160 disposed in the folding area FA may differ in structure and arrangement.

At least a part of the spacers 150 arranged in the non-folding area NFA may be configured such that the length of the specific width of the spacer 150 extending in the direction perpendicular to the folding axis is longer than the remaining width. That is, at least some of the spacers 150 disposed in the non-folding area NFA extend in the Y-axis direction, and the length of the width in the Y-axis direction may be longer than the remaining width.

At least some of the dual function spacers 160 disposed in the folding area FA are configured such that the length of the specific width of the dual function spacer 160 extending in the direction perpendicular to the folding axis is shorter than the remaining width .

2B, at least a part of the dual function spacers 160 disposed in the folding area FA may be formed of a double function spacer 160 extending in the same direction as the extending direction of the folding axis The length of the other width can be made the longest. That is, at least some of the dual function spacers 160 disposed in the folding area FA may extend or be arranged along the folding axis direction (X-axis direction).

Thus, the dual function spacer 160 can be configured to have the longest length of another width that intersects the shortest configured specific width. At this time, the shortest specific width of the dual function spacer 160 may be referred to as the short axis, and the longest specific width of the dual function spacer 160 may be referred to as the long axis. Thus, the intersecting major and minor axes of the dual function spacer 160 may be perpendicular to each other. That is, at least some of the dual function spacers 160 disposed in the folding area FA extend in the X-axis direction, the width in the X-axis direction is the longest, and the width in the Y- have. At this time, the dual function spacer 160 disposed in the folding region FA must protect the organic emission layer 132 without being damaged by an external impact. Therefore, the length of the width of the dual function spacer 160 in the Y-axis direction should be, for example, at least 2 탆 or more. The height of the double function spacer 160 should not be greater than the height of the sealing portion 140. For example, when the sealing portion 140 has a height of 3.5 占 퐉, the height of the dual function spacer 160 may be 3 占 퐉 or less.

The flexible substrate 101 can be folded (or folded) at a specific radius of curvature with respect to the folding axis of the folding area FA. At this time, the flexible substrate 101 can be stretched in the Y-axis direction. At this time, at least some of the dual function spacers 160 disposed in the folding area FA may be configured to have the shortest specific width. The specific width of the dual function spacer 160 is the width in the same direction as the direction in which the flexible substrate 101 is folded and stretched. That is, the short axis of the dual function spacer 160 can extend in the same direction as the direction in which the flexible substrate 101 is stretched when the substrate 101 is folded at a certain radius of curvature. Thus, the elongation of the dual function spacer 160 in the Y-axis direction can be minimized. That is, when the flexible substrate 101 is folded with respect to the folding axis in the folding area FA, the elongation of the dual function spacer can be minimized. Accordingly, when the foldable display device 100 is folded, the folding stress received by the dual function spacer 160 can be minimized.

The dual function spacer 160 disposed in the folding region FA and the spacer 150 disposed in the non-folding region NFA may be static tapered spacers. The constant tapered spacer means a spacer having a trapezoidal shape when viewed from one side, and the reverse staple spacer means a spacer having an inverted trapezoidal shape when viewed from one side. Constant taper spacers can minimize the particles generated during the spacer deposition process over reverse taper spacers. Therefore, the dual function spacer 160 disposed in the folding region FA and the spacer 150 disposed in the non-folding region NFA can be formed as constant taper spacers in the same process. That is, the dual function spacer 160 disposed in the folding area FA and the spacer 150 disposed in the non-folding area NFA may have the same shape.

Further, the reverse trapezoidal reverse tapered spacer has a larger area than that of the regular tapered spacer having a trapezoidal shape, but the thickness of the spacer can be thinned. When the foldable display device 100 is folded, the end of the reverse tapered spacer may be broken by the folding stress received by the spacer. Therefore, the reverse tapered spacer can generate foreign matter by breaking the spacer due to the folding stress. Since the constant tapered spacer becomes thicker at the tip toward the upper portion, breakage of the spacer due to folding stress can be minimized. Therefore, the constant tapered spacer can minimize foreign matter. The dual function spacer 160 disposed in the folding area FA may be a trapezoidal spacer when viewed from one side of the display device 100. Accordingly, the dual function spacer 160 disposed in the folding area FA is a constant taper spacer, and the folding stress can be minimized.

The size of the largest base line '' of the dual function spacer 160 may be greater than the size of the largest base line '' of the spacer 150 disposed in the non-folding area NFA. At this time, the area of the upper surface of the dual function spacer 160 disposed in the folding area FA may be larger than the area of the upper surface of the spacer 150 disposed in the non-folding area NFA. Folding stress is transmitted to the upper surface of the dual function spacer 160 when the foldable display device 100 is folded. At this time, the folding stress that the dual function spacer 160 receives per unit area is inversely proportional to the area of the upper surface of the dual function spacer 160. Therefore, as the area of the upper surface of the dual function spacer 160 is wider, the folding stress can be dispersed. That is, the area of the upper surface of the dual function spacer 160 disposed in the folding area FA is wider than the area of the upper surface of the spacer 150 disposed in the non-folding area NFA, . At this time, if the dual function spacer 160 has a structure capable of dispersing the folding stress, the shape of the upper surface may be a rectangular shape, a rhombus shape, or a polygonal shape.

Therefore, the dual function spacer 160 disposed in the folding area FA has a structure in which the folding stress is dispersed or the folding stress is minimized, so that when the foldable display device 100 is folded, the breakage can be suppressed have. Therefore, the foldable display device 100 can be improved in folding ease.

In addition, since the double function spacer 160 disposed in the folding region FA is prevented from breakage, particles generated due to the breakage of the spacer can be minimized. Foreign matter generated by breakage of the spacer can penetrate into the organic light emitting layer 132, and the height of the organic light emitting layer 132 can be changed. In addition, the foreign matter generated by breakage of the spacer may apply a magnetic field to the organic light emitting layer 132 to break the organic light emitting layer 132. When the height of the organic light emitting layer 132 is changed or the organic light emitting layer 132 is broken, a dark spot may be generated in the display device 100. The dark spot may be a defect of the display device 100 of the present invention. Therefore, the double function spacer 160 with the breakage suppressed by the reduction of the folding stress can minimize foreign matter. Accordingly, the change in the height of the organic luminescent layer 132 due to the foreign matter and the breakage of the organic luminescent layer 132 can be minimized, so that the occurrence of the dark spot can be suppressed and the luminance reduction of the display device 100 can be suppressed.

At this time, the area occupied by the spacers 150 and 160 in the display area AA of the display device 100 may be 0.25% to 1.25% of the total area of the display area AA, for example. The area occupied by the spacers 150 and 160 can be determined in consideration of various factors such as the size of the pixel, the arrangement of the TFT, the arrangement of the spacer, and the process.

Specifically, the area occupied by the spacer 150 disposed in the non-folding area NFA may be, for example, 0.45% to 0.5% of the total area of the display area AA. The area occupied by the dual function spacer 160 disposed in the folding area FA may be, for example, 0.45 to 1% or less of the total area of the display area AA. That is, the total area occupied by the dual function spacer 160 disposed in the folding area FA does not exceed twice the total area occupied by the spacer 150 disposed in the non-folding area NFA. The area occupied by the dual function spacer 160 disposed in the folding area FA in the entire area of the display area AA is determined by the folding stress received by the dual function spacer 160 when the foldable display device 100 is folded The area occupied by the spacer 150 disposed in the non-folding area NFA can be larger than the area occupied by the spacer 150. [

At this time, the size of each pixel of the display device 100 may be different. Therefore, the dual function spacer 160 disposed adjacent to the pixel can be formed in consideration of the size of the pixel. The pixel can be composed of a plurality of sub-pixels, and at least one dual function spacer 160 per sub-pixel can correspond. At this time, the smaller the size of the dual function spacer 160, the larger the adjacent sub-pixels can be formed, so that the brightness of the display device 100 can be improved. The dual function spacer 160 can be arranged to increase the density (or number) of the dual function spacers 160 that are small in the area where the dual function spacers 160 are disposed in the folding area FA. That is, it is possible to increase the density of the dual function spacers 160 by forming a plurality of relatively small dual function spacers 160, rather than forming one dual function spacer 160 in the same area. Accordingly, the folding stress experienced by the dual function spacer 160 can be minimized, and the size of the sub-pixel adjacent to the dual function spacer 160 can be made relatively larger. Accordingly, the brightness of the display device 100 can be improved.

At this time, the dual function spacer 160 may be formed of, for example, an acrylic material, a polyimide, a polyamide, a carbon compound, or a silicon material, no.

The dual function spacers 160 located on the banks 107 may also be located on the contact holes of the planarization layer 105. A portion of the anode electrode 131 may be located in the contact hole of the planarization layer 105 and electrically connected to the thin film transistor 120. When the display device 100 is folded, the light emitted from the organic light emitting layer 132 can be diffused by a part of the anode electrode 131 located inside the contact hole. Therefore, the (100) contact hole of the display device of the folder can be viewed, or a dark spot may be generated in the pixel due to the interference of light. At this time, a portion of the dual function spacer 160 may be overlapped with the contact hole of the planarization layer 105. Also, a part of the dual function spacer 160 may overlap with a part of the anode electrode 131 located in the contact hole. Thus, the dual function spacer 160 shields the contact holes, thereby minimizing internal panel reflection. At this time, one dual function spacer 160 can shield not only one contact hole but also the contact hole in the neighboring pixel. That is, one dual function spacer 160 may shield a plurality of contact holes.

As a result, the contact hole of the display device 100 can be viewed or the occurrence of dark points due to the interference of light can be minimized. Thus, the efficiency of suppressing the luminance reduction of the display device 100 can be improved.

FIGS. 3 to 5 are plan views showing the arrangement of spacers of the display device according to the embodiment of the present invention. 3 to 5 are plan views schematically depicting only the structure and arrangement of the spacers provided in the display device. Therefore, the configurations, positions, materials, and the like of other components are the same as those of the above-described foldable display device according to the present invention, and therefore duplicate description will be omitted.

For convenience of explanation, the spacer located in the non-folding region NFA is referred to as a first spacer 150, 350 and the dual function spacer 160, 260 located in the folding region FA is referred to as a second spacer 150, Spacers 160 and 260, respectively.

As shown in FIG. 3, spacers 150 and 160 may be located on the bank layer 107.

The first spacer 150 located in the unfolded region NFA may have a first width 151 and a second width 153 that is longer than the first width.

The second spacer 160 located in the folding region FA may have a third width 161 and a fourth width 163 that is shorter than the third width 161. At this time, the direction in which the third width 161 of the second spacer 160 extends may intersect the direction in which the second width 153 of the first spacer 150 extends. That is, the second spacer 160 may have a longer length of the third width 161, which is a width at which the second spacer 153 of the first spacer 150 intersects the extended direction. At this time, the direction in which the second width 153 extends and the direction in which the third width 161 extends may be orthogonal to each other.

Since the substrate 101 is folded on the basis of the folding axis in the folding area FA, it can be stretched in the Y-axis direction. At this time, since the fourth width 163 of the second spacer 160 is arranged in the Y-axis direction, the second spacer 160 can be extended in the fourth width 163 direction. The second spacers 160 may have a third width 163 such that the fourth width 163 is orthogonal to the folding axis and the stretching in the third width 161 direction is minimized so that the stretching in the fourth width 163 direction is minimized. (161) is parallel to the folding axis. At this time, the length of the fourth width 163 constituting the second spacer 160 is shorter than the length of the third width 161. Thus, the second spacer 160 can be minimally extended in the direction of the fourth width 163 when the substrate 101 is folded. That is, when the substrate 101 is folded with respect to the folding axis, the second spacer 160 is disposed in a stretch minimizing arrangement structure in which stretching is minimized, so that the folding stress experienced by the second spacers 160 can be minimized. Therefore, since the second spacer 160 disposed in the folding area FA can be prevented from being broken, the foldable display device 100 can be easily folded.

In addition, since breakage of the second spacer 160 disposed in the folding area FA is suppressed, foreign matter caused by breakage of the second spacer 160 can be minimized. This can minimize the change in the height of the organic luminescent layer 132 due to foreign matter and the breakage of the organic luminescent layer 132, thereby suppressing the occurrence of the dark spot and suppressing the luminance reduction of the display device 100. [

At this time, the first spacer 150 in which the non-folding region NFA is disposed and the second spacer 160 disposed in the folding region FA may have the same shape. Specifically, the length of the third width 161 of the second spacer 160 may be equal to the length of the second width 153 of the first spacer 150. The length of the fourth width 163 of the second spacer 160 may be the same as the length of the first width 151 of the first spacer 150. Accordingly, the first spacer 150 and the second spacer 160 can be formed in the same process. Accordingly, the process of forming the first spacer 150 and the second spacer 160 can be simplified, so that foreign matter generated by the breakage of the spacer due to repetition of the process can be minimized.

FIG. 4 is different from FIG. 3 only in the structure of the second spacer, and the remaining structures are the same, and a duplicate description will be omitted.

4, the second spacer 260 located in the folding region FA may have a third width 261 and a fourth width 263 that is shorter than the third width length . The length of the third width 261 of the second spacer 260 is longer than the length of the first width 151 of the first spacer and may be shorter than the length of the second width 153. The length of the fourth width 263 of the second spacer 260 is longer than the length of the first width 151 of the first spacer 150 and the length of the third width 261 of the second spacer 160 . That is, the length of the third width 261 and the fourth width 263 of the second spacer 260 may be longer than the length of the first width 151 of the first spacer 150. Therefore, the area of the upper surface of the second spacer 260 may be larger than the area of the upper surface of the first spacer 150. Folding stress is transmitted to the upper surface of the second spacer 260 when the foldable display 100 is folded. At this time, as the area of the upper surface of the second spacer 260 is larger, the folding stress can be dispersed. Therefore, breakage of the second spacer 260 disposed in the folding area FA can be suppressed, so that the foldable display device 100 can be improved in folding ease.

5 differs from FIG. 4 only in the first spacer structure, and the remaining structures are the same, so that redundant description is omitted.

As shown in FIG. 5, the first spacer 350 disposed in the non-folding region NFA may have the same shape as the second spacer 260 disposed in the folding region FA in FIG. Specifically, the length of the second width 353 of the first spacer 350 may be the same as the length of the third width 261 of the second spacer 260. The length of the first width 351 of the first spacer 350 may be equal to the length of the fourth width 263 of the second spacer 260. Accordingly, the first spacer 350 and the second spacer 260 can be formed in the same process. Accordingly, the process of forming the first spacer 350 and the second spacer 260 can be simplified, and foreign matter generated by the breakage of the spacer due to repetition of the process can be minimized.

Further, the area of the upper surface of the second spacer 260 can be made wide, and the folding stress can be dispersed. Therefore, breakage of the second spacer 260 disposed in the folding area FA can be suppressed, so that the foldable display device 100 can be improved in folding ease.

The features of the embodiments described above may be described as follows.

The present invention relates to a flexible substrate which is foldable; An array of pixels comprising light emitting devices on the flexible substrate; And an array of spacers located between the pixels, wherein the first spacers in the folding area of the spacers are arranged in a non-folding area, 2 spacers and at least one feature of their shape, number, position, density and area characteristics.

The closer one of the first spacers to the folding axis of the folded region, the more different at least one of the shape, the number, the position, the density, and the area characteristics may be different.

Each of the pixels is composed of a plurality of sub-pixels, one first spacer is associated with each sub-pixel, and the size of the corresponding first spacer may be different depending on the size of each sub-pixel.

When the folded region is inward folding, the size of the first spacers adjacent to the folding axis may be smaller than the size of the first spacers away from the folding axis.

In the case of outward folding of the folded region, the size of the first spacers adjacent to the folding axis may be greater than the size of the first spacers away from the folding axis.

Further, the features of the embodiments described above may be described as follows.

The present invention relates to a flexible substrate which is foldable; An array of pixels comprising light emitting devices on the flexible substrate; And an array of spacers located between the pixels, wherein at least some of the first spacers in the folding area of the spacers are in a non-folding area The second spacers being different in structure from at least a part of the second spacers.

At least one feature of the shape, number, position, density, and occupied area characteristics of the first spacers may be determined according to a particular folding radius of curvature of the flexible substrate in the folded area.

At least some of the first spacers may extend or be arranged along a folding axis direction.

The total area and density occupied by the first spacers do not exceed twice the total area and density occupied by the second spacers.

Each of the pixels is composed of a plurality of sub-pixels, and one first spacer is associated with each sub-pixel. The size of each of the first spacers is 2 占 퐉 or more and the height is 3 占 퐉 or less.

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

100: Foldable display device
110: organic light emitting display panel
120: thin film transistor
130: Organic light emitting device
140:
150, 350: a spacer (or first spacer)
160, 260: dual function spacer (or second spacer)

Claims (20)

A substrate having a folding region with a folding axis and an unfolded region;
A bank layer covering a part of an outer portion of an electrode electrically connected to the thin film transistor located on the substrate;
A first spacer located on the bank layer and having a first width and a second width greater than the length of the first width, the first spacer being located in the unfolded region; And
Having a third width greater in length in a direction extending in a direction intersecting with the extended direction of the second width and a fourth width shorter than the length of the third width, located in the folding region on the bank layer wherein the first spacer includes a second spacer whose crack is suppressed. The method according to claim 1,
Wherein the second spacers are arranged in a stretched minimized arrangement structure such that the substrate is folded with respect to the folding axis. 3. The method of claim 2,
Wherein the stretching minimized arrangement structure is a structure in which the fourth spacer is orthogonal to the folding axis so that the stretching in the longitudinal direction of the fourth width is minimized. The method of claim 3,
Wherein the stretching minimized arrangement structure has a structure in which the second spacer is parallel to the folding axis so that the stretching in the longitudinal direction of the third width is minimized. 5. The method of claim 4,
The length of the third width of the second spacer being the same as the length of the second width,
And the length of the fourth width of the second spacer is the same as the length of the first width. 5. The method of claim 4,
The length of the third width of the second spacer is longer than the length of the first width and shorter than the length of the second width,
The length of the fourth width of the second spacer is longer than the length of the first width and shorter than the length of the third width. A substrate composed of a folding region and an unfolding region;
A thin film transistor located on the substrate;
A first insulating layer covering the thin film transistor and having a contact hole;
An electrode disposed on the first insulating layer and electrically connected to the thin film transistor through the contact hole;
A second insulating layer located on the first insulating layer and covering a portion of the electrode and the contact hole;
An organic light emitting layer disposed on the electrode; And
And a dual function spacer located on the second insulating layer in the folding area, the double function spacer enabling easy folding and luminance reduction suppression. 8. The method of claim 7,
Wherein the dual function of the dual function spacer has a structure in which the folding stress is minimized so that breakage of the dual function spacer is suppressed. 9. The method of claim 8,
Wherein the structure in which the folding stress is minimized is configured such that the length of a specific width of the dual function spacer is shorter than the remaining width in the same direction as the direction in which the substrate is stretched, 10. The method of claim 9,
Wherein the dual function spacer has the longest length of another width perpendicular to the specific width. 11. The method of claim 10,
Wherein the dual function spacer has the same shape as the spacer disposed in the folding area. 12. The method of claim 11,
Wherein the dual function spacer has a trapezoidal shape when viewed from one side of the above-mentioned display device. 13. The method of claim 12,
Wherein the size of the largest base of the dual function spacer is larger than the size of the largest base of the spacer disposed in the unfolding region. 10. The method of claim 9,
Wherein the dual function spacer has a structure in which the reflection inside the panel is minimized, thereby improving the efficiency of suppressing the decrease in luminance. 15. The method of claim 14,
Wherein a structure in which reflection of the inside of the panel is minimized is a structure in which a part of the dual function spacer is positioned on the contact hole and overlapped and shielded. A foldable flexible substrate;
An array of pixels comprising light emitting devices on the flexible substrate; And
And an array of spacers located between the pixels,
Wherein at least some of the first spacers in the folding area of the spacers are different in structure from at least some of the second spacers in the non-folding area. 17. The method of claim 16,
Wherein at least one feature of the shape, number, position, density, and area features of the first spacers is determined by a specific folding radius of curvature of the flexible substrate in the folded region. 18. The method of claim 17,
Wherein at least some of the first spacers are extended or arranged along a folding axis direction. 19. The method of claim 18,
Wherein the total area and density occupied by the first spacers do not exceed twice the total area and density occupied by the second spacers. 20. The method of claim 19,
Wherein each of the pixels is composed of a plurality of sub-pixels, one first spacer is associated with each sub-pixel, and each of the first spacers has a size of 2 mu m or more and a height of 3 mu m or less.

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