Display device

Abstract

To provide a display device capable of having a narrower frame.SOLUTION: A display device includes a substrate including a display region including a plurality of pixels, and an end part region including a connection part, a flexible wiring board including a wire and a flexible base material, and a driving IC chip provided on the flexible wiring board. The flexible wiring board is bent in a bent region. The driving IC chip includes a protection member facing the display region, extending from an end part of the substrate, and overlapping with the wire of the flexible wiring board. The protection member has an elastic modulus of 10 MPa or more and 20 MPa or less.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present embodiment relates to a display device. [Background technology]

[0002] 2. Description of the Related Art A flat panel display such as an organic electroluminescence (EL) display device has a display panel in which thin film transistors (TFTs), organic light-emitting diodes (OLEDs), and the like are formed on a substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-003788 A Summary of the Invention [Problem to be solved by the invention]

[0004] This embodiment provides a display device that can have a narrow frame. [Means for solving the problem]

[0005] A display device according to an embodiment includes: a substrate having a display region having a plurality of pixels and an edge region having a connection portion; A flexible wiring board including wiring and a flexible base material; A driving IC chip provided on the flexible wiring board; The flexible wiring board is folded at a folding region, the driving IC chip faces the display area, a protective member extending from an end of the substrate and overlapping the wiring of the flexible wiring substrate; Equipped with The protective member has an elastic modulus of 10 MPa or more and 20 MPa or less. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing a configuration example of a display device according to an embodiment. [Diagram 2] FIG. 2 is a diagram of the display device shown in FIG. 1 as viewed from the rear side. [Diagram 3] FIG. 3 is a cross-sectional view showing an example of a schematic configuration of a display device of a comparative example. [Figure 4] FIG. 4 is a cross-sectional view showing an example of a schematic configuration of a display device of a comparative example. [Diagram 5] FIG. 5 is a cross-sectional view showing an example of a schematic configuration of the display device according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing an example of a schematic configuration of a display device according to an embodiment. [Figure 7] FIG. 7 is a diagram showing the relationship between the elastic modulus of the protective member and the distance that the flexible wiring board protrudes outward from the end of the board. [Figure 8] FIG. 8 is a partial plan view showing an example of a schematic configuration of a display panel. [Figure 9] FIG. 9 is a cross-sectional view taken along line A1-A2 of the display panel shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while maintaining the gist of the invention, which are naturally included in the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments described in this specification are not general, but are embodiments describing the same or corresponding special technical features of the present invention.

[0009] In this embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but may intersect at an angle other than 90 degrees. The direction toward the tip of the arrow of the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow of the third direction Z is defined as down or downward. The first direction X, the second direction Y, and the third direction Z may also be called the X direction, the Y direction, and the Z direction, respectively.

[0010] Furthermore, in the case of "a second member above the first member" and "a second member below the first member," the second member may be in contact with the first member or may be located away from the first member. In the latter case, a third member may be interposed between the first and second members. On the other hand, in the case of "a second member above the first member" and "a second member below the first member," the second member is in contact with the first member.

[0011] Also, it is assumed that an observation position for observing the display device is located at the tip side of the arrow in the third direction Z, and a planar view refers to a view from this observation position toward the XY plane defined by the first direction X and the second direction Y. A cross-sectional view refers to a view of a cross section of the display device in the XZ plane defined by the first direction X and the third direction Z, or in the YZ plane defined by the second direction Y and the third direction Z.

[0012] [Embodiment] Fig. 1 is a perspective view showing a configuration example of a display device according to this embodiment. The display device DSP shown in Fig. 1 includes, for example, an active matrix display panel PNL.

[0013] The display device DSP has a display area DA and a peripheral area FA provided around the display area DA on a substrate SUB1. The display device DSP has a plurality of pixels PX arranged in the display area DA. In the display device DSP, light LT from the pixels PX is emitted upward.

[0014] The surface of the display panel PNL from which the light LT is emitted is referred to as a surface FF. The surface opposite the surface FF in the third direction Z is referred to as a surface RF. The surface FF can be said to be an emission surface, a front surface, or a top surface, and the surface RF can be said to be a back surface or a bottom surface.

[0015] An edge area EA of the substrate SUB1 is disposed outside the display area DA. The area EA is also called an edge area of ​​the display panel PNL. A connection part WPD is provided in the area EA. Wiring from the display area DA extends to the connection part WPD. The wiring from the display area DA is a scanning line or a signal line from the pixel PX, or a wiring connected to the scanning line or the signal line.

[0016] A flexible wiring board FPC1 is provided in the connection part WPD of the area EA. The flexible wiring board FPC1 has a plurality of wirings arranged along the first direction X. The wirings of the flexible wiring board FPC1 are electrically connected to the connection part WPD by an anisotropic conductive film (ACF). This electrically connects the wirings from the display area DA and the wirings of the flexible wiring board FPC1.

[0017] An end of flexible wiring board FPC1 that is close to connection part WPD is defined as end EF11. An end opposite end EF11 in second direction Y is defined as end EF12. Of the faces of flexible wiring board FPC1, a face on the same side as face FF is defined as face FP. Of the faces of flexible wiring board FPC1, a face on the same side as face RF is defined as face RP.

[0018] The flexible wiring board FPC1 is mounted with a driving IC chip ICP as a signal supply source that supplies signals necessary to drive the display panel PNL. That is, the flexible wiring board FPC1 is a COF (Chip On Film). An end EF12 of the flexible wiring board FPC1 extends from an end ES11 of the substrate SUB1. The driving IC chip ICP is provided in the extended area.

[0019] Fig. 2 is a view of the display device shown in Fig. 1 as seen from the back side. As shown in Fig. 2, the flexible wiring board FPC1 of the display device DSP is folded back to the surface RF side, which is the back side of the display panel PNL. The area where the flexible wiring board FPC1 is folded back is called the folding area BND. The area of ​​the flexible wiring board FPC1 that is folded back to the surface RF side of the display panel PNL is called the area BSF.

[0020] The length (width) of the bending region BND along the second direction Y is defined as length db (see FIG. 1). The smaller the bending region BND, the narrower the frame can be. In other words, the smaller the length db, the narrower the frame can be. However, the smaller the length db, the smaller the curvature, which may cause breaks in the flexible wiring board FPC1.

[0021] Therefore, in this embodiment, a reinforcing resin is provided in the bending region BND to reinforce the bending region BND.

[0022] Here, a display device of a comparative example will be described. Figures 3 and 4 are cross-sectional views showing an example of a schematic configuration of a display device of a comparative example. Figure 3 is a cross-sectional view of the display device in a folded state. Figure 4 is a cross-sectional view of the display device in a state before being folded.

[0023] The display device DSP includes a substrate SUB1, a polarizing plate POL, an adhesive ADH, an anisotropic conductive film ACF, a flexible wiring board FPC1, a protective member UVR, a protective member PRS, a protective member FMT, a protective member DST, a protective member SRT, and a driving IC chip ICP.

[0024] The substrate SUB1, the polarizing plate POL, the adhesive ADH, the flexible wiring board FPC1, and the driving IC chip ICP constitute the display panel PNL. The flexible wiring board FPC1 includes a base material FPCB and wiring FPCL having flexibility.

[0025] In the display device DSP shown in Fig. 3, the flexible wiring board FPC1 is bent at a bending region BND. More specifically, the bending region BND has a flat region BNDF and a region BNDR having a curve. The bending region BND can also be said to be a region protruding from the end ES11 of the substrate SUB1. By bending the flexible wiring board FPC1 at the bending region BND, the distance dh protruding outward from the end ES11 of the substrate SUB1 is reduced, making it possible to narrow the frame.

[0026] A polarizing plate POL is attached to the substrate SUB1 by an adhesive ADH. The adhesive ADH is, for example, an optical adhesive having light-transmitting properties. Of the surfaces of the polarizing plate POL, the surface opposite to the surface facing the substrate SUB1 corresponds to the surface FF of the display panel PNL. The polarizing plate POL is, for example, a circular polarizing plate. By providing the polarizing plate POL, for example, it is possible to suppress reflection of external light in the display area DA of the display panel PNL.

[0027] Of the surfaces of the substrate SUB1, the surface facing the polarizing plate POL is referred to as surface FS. The surface opposite to surface FS is referred to as surface RS. Surface RS of the substrate SUB1 corresponds to surface RF of the display panel PNL.

[0028] In the region EA of the substrate SUB1, an anisotropic conductive film ACF is provided on the connection portion WPD. The wiring of the substrate SUB1 and the wiring FPCL of the flexible wiring board FPC1 are electrically connected by the anisotropic conductive film ACF.

[0029] On the area EA, a protection member UVR is provided between the end EP11 of the polarizing plate POL and the end EF11 of the flexible wiring board FPC1.

[0030] The protective member UVR may be made of, for example, a photocurable resin material. The protective member UVR is provided so as not to leave a gap between the polarizing plate POL and the protective member UVR. The protective member UVR is disposed for the purpose of protecting the polarizing plate POL or the wiring and electrode parts not covered with the anisotropic conductive film ACF from moisture.

[0031] Between the substrate SUB1 and the region BSF of the flexible wiring board FPC1, along the direction opposite to the third direction Z, a protection member FMT, a protection member DST, and a driving IC chip ICP are arranged.

[0032] The protective member FMT is a protective member in which a tape is provided on the front and back surfaces of a base material having cushioning properties. In other words, the protective member FMT can be said to be a double-sided tape having cushioning properties. The protective member DST is a member having an adhesive layer on the front and back surfaces, for example, a double-sided tape. The protective member DST may also have cushioning properties.

[0033] The protective members FMT and DST bond the driving IC chip ICP and the region BSF of the flexible wiring board FPC1 provided on the substrate SUB1. The protective member FMT has a cushioning base material and thus has the function of maintaining a certain distance between the bent flexible wiring board FPC1 and the driving IC chip ICP. This keeps the curvature of the bending region BND within an allowable range even if pressure is applied to the flexible wiring board FPC1 in the thickness direction (third direction Z).

[0034] A protective member SRT is provided in contact with the wiring FPCL of the flexible wiring board FPC1. The protective member SRT is formed of, for example, a heat-resistant resin material, more specifically, a so-called solder resist. The protective member SRT is provided in a region where the wiring FPCL is provided, other than a region in contact with the anisotropic conductive film ACF and a region in contact with the driving IC chip ICP. The protective member SRT protects the wiring FPCL.

[0035] The protective member PRS extends from the end ES11 of the substrate SUB1 in the second direction Y and overlaps with a portion of the protective member SRT. A portion of the anisotropic conductive film ACF and a portion of the wiring FPCL are exposed near the end ES11 of the substrate SUB1. The protective member PRS protects the exposed portion of the anisotropic conductive film ACF and the wiring FPCL. If the protective member PRS is not provided, the exposed portion of the wiring FPCL may be damaged by the end ES11 of the substrate SUB1, which may result in disconnection of the wiring FPCL. Furthermore, by providing the protective member PRS, the strength of the connection part WPD can be ensured.

[0036] The protective member PRS may be made of, for example, a resin material. However, if the elastic modulus of the resin material is high, the flexible wiring board FPC1 becomes difficult to bend. The length of the flat area BNDF in the bending area BND becomes long, and the distance dh becomes long.

[0037] Therefore, in this embodiment, a resin material with a low modulus of elasticity, for example, a resin material with a modulus of elasticity of 10 MPa or more and 20 MPa or less, is used as the protective member PRS. If such a resin material with a low modulus of elasticity is used, when the flexible wiring board FPC1 is bent, the protective member PRS is crushed and bent together with the flexible wiring board FPC1. This makes it possible to reduce the distance dh by which the flexible wiring board FPC1 protrudes outward from the end portion ES11. This makes it possible to narrow the frame of the display device DSP.

[0038] Figures 5 and 6 are cross-sectional views showing an example of a schematic configuration of a display device according to an embodiment. Figure 5 is a cross-sectional view of the display device in a folded state. Figure 6 is a cross-sectional view of the display device before being folded. The display device shown in Figures 5 and 6 is different from the display device shown in Figures 3 and 4 in that the protective member PRS is made of a resin material having a low elastic modulus.

[0039] The display device DSP shown in Figures 5 and 6 is the same as the display device DSP shown in Figures 3 and 4, except that the protective member PRS uses a resin material with a low elastic modulus. Therefore, the description of the display device DSP shown in Figures 5 and 6 other than the protective member PRS will be omitted by citing the description of Figures 3 and 4.

[0040] The protective member PRS of the comparative example (see FIG. 3) is provided in the flat region BNDF of the region BND. On the other hand, the protective member PRS of the present embodiment (see FIG. 5) extends not only in the flat region BNDF of the region BND but also so as to overlap with a part of the region BNDR having a curve.

[0041] The protective member PRS of the present embodiment is made of a resin material with a low elastic modulus, so that when the flexible wiring board FPC1 is bent, the protective member PRS is crushed and folded together with the flexible wiring board FPC1 as described above. On the other hand, the protective member PRS of the comparative example has a high elastic modulus, so that when the flexible wiring board FPC1 is bent, the protective member PRS is not folded together with the flexible wiring board FPC1. Therefore, the protective member PRS of the comparative example is not provided in the region BNDR having a curve.

[0042] Fig. 7 is a diagram showing the relationship between the elastic modulus of the protective member and the distance that the flexible wiring board protrudes outward from the end of the substrate. As shown in Fig. 7, when a resin material with an elastic modulus of 50 MPa to 60 MPa is used as the protective member PRS, the distance dh is 0.3 mm to 0.5 mm.

[0043] On the other hand, when a resin material having an elastic modulus of 10 MPa or more and 20 MPa or less is used as the protective member PRS, the distance dh is 0.1 mm or more and 0.2 mm or less. In this way, the distance dh protruding from the end ES11 of the substrate SUB1 is reduced, so that the frame of the display device DSP can be narrowed.

[0044] Here, the pixels PX of the display panel PNL will be explained in more detail.

[0045] 8 is a partial plan view showing an example of a schematic configuration of a display panel. The pixels PX include a pixel PXR that emits red light, a pixel PXG that emits green light, and a pixel PXB that emits blue light. The pixels PXR, PXG, and PXB are also referred to as a first pixel, a second pixel, and a third pixel, respectively. The pixel PXR is disposed adjacent to the pixel PXB along the first direction X and the second direction Y. The pixel PXG is disposed adjacent to the pixel PXB along the first direction X and the second direction Y. The pixel PXB is disposed adjacent to the pixel PXR along the first direction, and adjacent to the pixel PXG along the second direction Y.

[0046] FIG. 9 is a cross-sectional view taken along line A1-A2 of the display panel shown in FIG. The base material BA1 is an insulating base material, for example, glass.

[0047] An insulating layer UC1 is provided on the base material BA1. The insulating layer UC1 is formed of, for example, a single layer or a laminate of a silicon oxide film and a silicon nitride film.

[0048] A light-shielding layer BM may be provided on the insulating layer UC1 so as to overlap the transistor Tr. The light-shielding layer BM suppresses changes in transistor characteristics due to light intrusion from the back surface of the channel of the transistor Tr. When the light-shielding layer BM is formed of a conductive layer, it is also possible to provide a backgate effect to the transistor Tr by applying a predetermined potential.

[0049] An insulating layer UC2 is provided to cover the insulating layer UC1 and the light-shielding layer BM. The insulating layer UC2 may be made of the same material as the insulating layer UC1. The insulating layer UC2 may be made of a different material from the insulating layer UC1. For example, the insulating layer UC1 may be made of silicon oxide, and the insulating layer UC2 may be made of silicon nitride. The insulating layers UC1 and UC2 are collectively referred to as the insulating layer UC.

[0050] A transistor Tr is provided on the insulating layer UC. The transistor Tr has a semiconductor layer SC, an insulating layer GI, a gate electrode GE (scanning line GL), an insulating layer ILI, a source electrode SE (signal line SL), and a drain electrode DE. The transistor Tr is a thin film transistor (TFT).

[0051] The semiconductor layer SC is made of amorphous silicon, polysilicon, or an oxide semiconductor. The insulating layer GI is formed, for example, by using a single layer or a stack of layers of silicon oxide or silicon nitride.

[0052] The gate electrode GE is made of, for example, a molybdenum tungsten alloy (MoW). The gate electrode GE may be formed integrally with the scanning line GL.

[0053] An insulating layer ILI is provided to cover the semiconductor layer SC and the gate electrode GE. The insulating layer ILI is formed of, for example, a single layer or a multilayer of silicon oxide layers or silicon nitride layers.

[0054] A source electrode SE and a drain electrode DE are provided on the insulating layer ILI. The source electrode SE and the drain electrode DE are connected to the source region and the drain region of the semiconductor layer SC via contact holes provided in the insulating layer ILI and the insulating layer GI, respectively. The source electrode SE may be formed integrally with the signal line.

[0055] An insulating layer PAS is provided covering the source electrode SE, the drain electrode DE, and the insulating layer ILI. An insulating layer PLL is provided covering the insulating layer PAS.

[0056] The insulating layer PAS is formed using an inorganic insulating material. Examples of the inorganic insulating material include a single layer or a laminate of silicon oxide or silicon nitride. The insulating layer PLL is formed using an organic insulating material. Examples of the organic insulating material include polyimide and acrylic resin insulating materials. By providing the insulating layer PLL, the step caused by the transistor Tr can be flattened.

[0057] An anode AD is provided on the insulating layer PLL. The anode AD is connected to the drain electrode DE via a contact hole provided in the insulating layer PAS and PLL. The anode provided in the pixel PXR is referred to as the anode ADR, the anode provided in the pixel PXB is referred to as the anode ADB, and the anode provided in the pixel PXG is referred to as the anode ADG. When there is no need to distinguish between the anode ADR, anode ADG, and anode ADB, they are simply referred to as the anode AD.

[0058] The anode AD may be formed, for example, of a laminate of a reflective electrode and a transparent electrode. The reflective electrode is formed of a conductive material with high reflectivity, for example, silver (Ag) or aluminum (Al). The transparent electrode is formed, for example, of indium tin oxide (ITO) or indium zinc oxide (IZO). In this embodiment, the configuration from the substrate BA1 to the insulating layer PLL is referred to as a backplane BPS.

[0059] A bank BK (also called a protrusion or rib) is provided between adjacent anodes AD. The bank BK is made of an organic material similar to that of the insulating layer PLL. The bank BK is opened so as to expose a part of the anode AD.

[0060] The opening provided in pixel PXR is referred to as an opening OPR, the opening provided in pixel PXB is referred to as an opening OPB, and the opening provided in pixel PXG is referred to as an opening OPG. When there is no need to distinguish between the openings OPR, OPB, and OPG, they are simply referred to as openings OP.

[0061] The edge of the opening OP preferably has a gently tapered shape in cross section, since if the edge of the opening OP has a steep shape, poor coverage will occur in the organic EL layer ELY to be formed later.

[0062] The organic EL layer ELY is provided between the adjacent banks BK so as to overlap with the anode AD. The organic EL layer ELY includes a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. The organic EL layer ELY may further include an electron blocking layer and a hole blocking layer, if necessary.

[0063] The organic EL layer provided in pixel PXR is referred to as organic EL layer ELYR, the organic EL layer provided in pixel PXB is referred to as organic EL layer ELYB, and the organic EL layer provided in pixel PXG is referred to as organic EL layer ELYG. When there is no need to distinguish between the organic EL layer ELYR, the organic EL layer ELYG, and the organic EL layer ELYB, they are simply referred to as the organic EL layer ELY.

[0064] A cathode CD is provided on the organic EL layer ELY. The cathode CD is formed using, for example, a magnesium-silver alloy (MgAg) film, a single layer film of silver (Ag), or a laminate film of silver (Ag) and a transparent conductive material. The transparent conductive material may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or the like.

[0065] An insulating layer SEY is provided to cover the cathode CD. The insulating layer SEY has a function of preventing moisture from entering the organic EL layer ELY from the outside. The insulating layer SEY is preferably one having high gas barrier properties. As the insulating layer SEY, for example, an insulating layer in which an organic insulating layer is sandwiched between two inorganic insulating layers containing nitrogen can be mentioned. Examples of materials for the organic insulating layer include resin insulating materials such as polyimide and acrylic. Examples of materials for the inorganic insulating layer containing nitrogen can be silicon nitride and aluminum nitride.

[0066] Light emitted from the organic EL layer ELY is extracted upward through the cathode CD. That is, the display device DSP (display panel PNL) of this embodiment has a top emission structure.

[0067] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0068] BND...area, BNDF...area, BNDR...area, BSF...area, DA...display area, DSP...display device, DST...protective material, EA...area, FMT...protective material, FPC1...flexible wiring board, FPCB...substrate, FPCL...wiring, ICP...driver IC chip, PNL...display panel, PRS...protective material, SRT...protective material, SUB1...substrate, UVR...protective material.

Claims

1. a substrate having a display region having a plurality of pixels and an edge region having a connection portion; A flexible wiring board including wiring and a flexible base material; A driving IC chip provided on the flexible wiring board; The flexible wiring board is folded at a folding region, the driving IC chip faces the display area, a protective member extending from an end of the substrate and overlapping the wiring of the flexible wiring substrate; Equipped with The display device, wherein the protective member has an elastic modulus of 10 MPa or more and 20 MPa or less.

2. The bending region has a flat region and a region having a curvature, The display device according to claim 1 , wherein the protective member overlaps the region having the curvature.

3. The display device according to claim 1 , further comprising a cushioning double-sided tape provided between the driving IC chip and the display area.

4. The display device according to claim 1 , further comprising a polarizing plate provided on the substrate.

5. The display device according to claim 1 , further comprising a heat-resistant resin provided to cover the wiring of the flexible wiring board.

6. The display device according to claim 1 , wherein the wiring and the connection portion of the flexible wiring board are electrically connected by an anisotropic conductive film.

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