Display device

Abstract

To provide a display device in which the decrease in yield can be suppressed.SOLUTION: A display device includes a flexible base material, a first insulating layer provided on the base material, a wire provided on the first insulating layer, and a second insulating layer covering the wire and the first insulating layer. The display device includes a display region and an end region including a bent region. The second insulating layer includes a first region having a first thickness, and a second region having a second thickness larger than the first thickness. The second region overlaps with the bent region. A neutral plane of a multilayer structure of the base material, the first insulating layer, the wire, and the second insulating layer occurs in the wire.SELECTED DRAWING: Figure 11

Description

[Technical field]

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

[0002] 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), etc. are formed on a substrate. Conventionally, a glass substrate has been used as the base material for the display panel, but in recent years, flexible displays that use a resin film or the like as the base material and allow the display panel to be bent have been developed.

[0003] One possible use for flexible displays is to fold the part of the display panel that is located outside the image display area and on which integrated circuits (ICs) and flexible printed circuits (FPCs) are mounted to the back of the display area to create a narrower frame. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-152527 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present embodiment provides a display device capable of suppressing a decrease in yield. [Means for solving the problem]

[0006] A display device according to an embodiment includes: A flexible substrate; A first insulating layer provided on the substrate; A wiring provided on the first insulating layer; a second insulating layer covering the wiring and the first insulating layer; A display device comprising: The display device has a display region and an end region having a folding region, the second insulating layer has a first region having a first thickness and a second region having a second thickness greater than the first thickness; The second region overlaps the folding region, A midplane of the laminated structure of the base material, the first insulating layer, the wiring, and the second insulating layer occurs in the wiring. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is an overall perspective view of a display device according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing an example of a schematic configuration of a display device of a comparative example. [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 an enlarged cross-sectional view of a portion of FIG. [Diagram 5] FIG. 5 is a cross-sectional view of a display device of another comparative example. [Figure 6] FIG. 6 is a cross-sectional view of a display device of another comparative example. [Figure 7] FIG. 7 is a partially enlarged cross-sectional view of the bending region. [Figure 8] FIG. 8 is a diagram showing the relationship between the radius of curvature when the display device is folded and the distance from the lower surface of the base material to the neutral plane. [Figure 9] FIG. 9 is a diagram showing the relationship between the radius of curvature when the display device is folded and the distance from the lower surface of the base material to the neutral plane. [Figure 10] FIG. 10 is a diagram showing the relationship between the radius of curvature and the distance from the lower surface of the base to the neutral plane when the display device of the embodiment is folded. [Figure 11]FIG. 11 is a cross-sectional view showing an example of a schematic configuration of a display device according to an embodiment. [Figure 12] FIG. 12 is a partial plan view showing an example of a schematic configuration of a display panel. [Figure 13] FIG. 13 is a cross-sectional view taken along line A1-A2 of the display panel shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] 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.

[0013] [Embodiment] 1 is an overall perspective view of a display device according to an embodiment. 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] 1, the substrate SUB1 and the multiple pixels PX are collectively referred to as the display panel PNL. The surface of the display panel PNL that emits the light LT is referred to as the surface FF. The surface opposite the surface FF in the third direction Z is referred to as the surface RF. The surface FF can be said to be the emission surface, front surface, or top surface, and the surface RF can be said to be the back surface or bottom surface.

[0015] An area EA at the edge of the substrate SUB1 is disposed outside the display area DA. Of the area EA, an area close to the display area DA will be referred to as an edge ES11. Of the area EA, an edge away from the display area DA along the second direction Y will be referred to as an edge ES12. Of the surfaces of the substrate SUB1, a surface that emits light LT will be referred to as a surface FL. A surface opposite to surface FL will be referred to as a surface RL. Surface RL is the same surface as surface RF. The area EA will also be referred to as an edge area of ​​the display panel PNL.

[0016] A connection part WPD is provided in the area EA on the end ES12 side. 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.

[0017] Between the end ES11 and the end ES12 of the area EA, an area BND is provided. Between the area BND and the end ES12, an area BSF is provided. The area BND is a folding area, and the area BSF is an area that is folded upside down. The areas BND and BSF will be described in detail later.

[0018] A flexible wiring board FPC1 is provided in the connection part WPD of the area EA. The flexible wiring FPC1 has a plurality of wires arranged along the first direction X. The wires of the flexible wiring board FPC1 are electrically connected to the connection part WPD by an anisotropic conductive film (ACF). This electrically connects the wires from the display area DA and the wires of the flexible wiring FPC1.

[0019] Among the ends of flexible wiring FPC1, an end close to connection part WPD is defined as end EF11. Along the second direction Y, an end opposite end EF11 is defined as end EF12. End EF11 is closer to end ES12 of substrate SUB1 than end EF12. In other words, end EF11 is located between end EF12 and end ES12.

[0020] End EF12 of flexible wiring board FPC1 is electrically connected to the printed circuit board PCB. The end of the printed circuit board PCB connected to end EF12 of flexible wiring board FPC1 is defined as end EB11. The end opposite end EB11 along the second direction Y is defined as end EB12. End EB11 is closer to end ES12 of substrate SUB1 than end EB12. In other words, end EB11 is located between end EB12 and end ES12.

[0021] The flexible wiring board FPC1 and the printed circuit board PCB may be collectively referred to as the flexible wiring board FPC. Alternatively, the printed circuit board PCB may not be provided, and only the flexible wiring board FPC1 may be provided.

[0022] The flexible wiring FPC1 may be provided with a driving element that outputs a video signal and a driving signal. The signal from the driving element is input to the pixel PX in the display area DA via the flexible wiring board FPC1. The pixel PX emits light based on the video signal and various control signals.

[0023] The substrate SUB1 includes a flexible base material (base material BA1 described later) and a plurality of pixels PX. The base material may be formed of, for example, a resin film material, more specifically, acrylic, polyimide, polyethylene terephthalate, polyethylene naphthalate, or the like. A plurality of pixels PX including a plurality of switching elements, a plurality of scanning lines, a plurality of signal lines, a plurality of pixel electrodes, a common electrode, a plurality of light-emitting layers, and the like are provided on the base material. A detailed configuration of the pixels PX, etc. will be described later.

[0024] Since the substrate SUB1 is flexible, the display panel PNL is a flexible display.

[0025] Here, a display device of a comparative example will be described. Figures 2 and 3 are cross-sectional views showing an example of a schematic configuration of a display device of a comparative example. Figure 2 is a cross-sectional view of the display device of the comparative example in a folded state. Figure 3 is a cross-sectional view of the display device of the comparative example in a state before being folded.

[0026] The display device DSP includes a display panel PNL, a polarizing plate POL, an optical adhesive OCA1, a cover material CG, a protective member BPT, a protective member UVR, a protective member PRS, a protective member DST, and a flexible wiring board FPC.

[0027] 2, the display panel PNL is folded at the region BND. By folding the display panel PNL at the region BND, the region EA including the connection portion WPD becomes smaller, and the frame can be narrowed.

[0028] The region BSF of the display panel PNL overlaps a part of the display region DA in the direction opposite to the third direction Z. Between the part of the display region DA and the region BSF, the protective members BPT, DST, and SPT are arranged along the direction opposite to the third direction Z.

[0029] A polarizing plate POL is provided on the surface FF side of the display panel PNL in contact with the display area DA. 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.

[0030] A cover material CG is provided on the polarizing plate POL with an optical adhesive OCA1. The cover material CG may be, for example, a thin plate made of glass or plastic.

[0031] A protective member BPT is provided on the surface RF side of the display panel PNL. Of the surfaces of the protective member BPT, the surface that contacts the surface RF of the display panel PNL is referred to as surface FB. Of the surfaces of the protective member BPT, the surface opposite surface FB is referred to as surface RB. A protective member DST is provided in contact with a portion of surface RB. The protective member BPT generally overlaps the display area DA of the display panel PNL. More specifically, the protective member BPT overlaps the display area DA and portions of area EA.

[0032] Among the surfaces of the protective member DST, the surface that contacts the surface RB of the protective member BPT is referred to as a surface FP. Among the surfaces of the protective member DST, the surface opposite to the surface FP is referred to as a surface RP. The protective member SPT is provided in contact with the surface RP. The protective member SPT overlaps the region BSF.

[0033] Of the surfaces of the protective member SPT, the surface that contacts the surface RP of the protective member DST is referred to as surface FS. Of the surfaces of the protective member SPT, the surface opposite to surface FS is referred to as surface RS. Surface RS contacts surface RF of the region BSF of the display panel PNL (surface RL of the substrate SUB1).

[0034] The protective members BPT and SPT may be made of a plate-shaped resin material, for example, plate-shaped polyethylene terephthalate (PET). The protective members BPT and SPT are attached to the surface RF of the display panel PNL and face each other in the third direction Z, sandwiching the protective member DST therebetween. This provides a function of protecting the display panel PNL.

[0035] The protective member DST is a member having adhesive layers on the front and back surfaces, for example, a double-sided tape. The protective member DST bonds the protective member SPT and the protective member BPT. More preferably, the protective member DST is made of a resin material having cushioning properties. The protective member DST has a function of maintaining the gap of the folded display panel PNL at a certain level or more. This keeps the curvature of the region BND within an allowable range even if pressure is applied to the display panel PNL in the thickness direction (third direction Z).

[0036] The protective member UVR is provided in contact with the surface FL in the region BND of the display panel PNL. The protective member UVR has a function of protecting the bending region BND of the display panel PNL. The protective member UVR is provided in contact with the surface FL of the display panel PNL between the end of the polarizing plate POL and the end EF11 of the flexible wiring board FPC.

[0037] 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. If a gap exists between the polarizing plate POL and the protective member UVR, the display panel PNL will break from the gap during the process of bending the display panel PNL, causing the wiring of the display panel PNL to break.

[0038] A protective member PRS is provided near the end portion ES12 of the display panel PNL, in contact with the end portion ES12, the protective member SPT, and the flexible printed circuit board FPC.

[0039] The protective member PRS may be made of, for example, a resin material, and has a function of protecting the edge portion ES12 of the display panel PNL.

[0040] Fig. 4 is an enlarged cross-sectional view of a part of Fig. 2. Fig. 4 is an enlarged view of a portion from near the end of the polarizing plate POL to the end EF11 of the flexible wiring board FPC1, showing the state before the display device DSP shown in Fig. 2 is folded.

[0041] The display panel PNL shown in Fig. 4 includes a base material BA1, an insulating layer BPLN, lead-out wiring LW, and an insulating layer PLN. The insulating layer BPLN is provided to cover the base material BA1. The lead-out wiring LW is provided on the insulating layer BPLN. The insulating layer PLN is provided to cover the lead-out wiring LW and the insulating layer BPLN.

[0042] The flexible wiring board FPC1 is connected to the lead wiring LW via a contact hole provided in the insulating layer PLN.

[0043] The base material BA1 is a base material having the above-mentioned flexibility. As described above, the base material BA1 may be a resin film.

[0044] The lead-out wiring LW is a wiring formed of a metal material. The lead-out wiring LW is formed of a three-layer structure in which titanium (Ti), aluminum (Al), and titanium (Ti) are stacked in the order listed. However, the material of the lead-out wiring LW is not limited to this. For example, it may be a single layer of tantalum (Ta), tungsten (W), molybdenum (Mo), copper (Cu), or silver (Ag), or a stack of these.

[0045] The insulating layer BPLN and the insulating layer PLN are formed of an elastically deformable material. The elastically deformable material is, for example, a resin insulating material such as polyimide or acrylic. The elastic deformation will be described in detail later. The insulating layer BPLN and the insulating layer PLN have the function of flattening their surfaces.

[0046] The protection member UVR has an end EU11 adjacent to the end EP11 of the polarizing plate POL, and an end EU12 adjacent to the end EF11 of the flexible wiring board FPC. The end EP11 and the end EU11 are in contact with each other.

[0047] 2 and 4, the protective member UVR is provided so as not to create a gap between the polarizing plate POL. If a gap exists between the polarizing plate POL and the protective member UVR, the display panel PNL will break from the gap during the process of bending the display panel PNL, causing the wiring of the display panel PNL to be disconnected.

[0048] Fig. 5 is a cross-sectional view of a display device of another comparative example. In the display device DSP shown in Fig. 5, the protection member UVR is disposed at a distance from the polarizing plate POL, as compared with the display device DSP shown in Fig. 4.

[0049] In the display device DSP shown in Fig. 5, an end EU11 of the protection member UVR is separated from an end EP11 of the polarizing plate POL. In Fig. 5, a reinforcing member MPT is provided in contact with the surface of the protection member BPT opposite to the surface in contact with the base material BA1.

[0050] The reinforcing member MPT is formed of, for example, a metal material or a reinforced plastic material. Since the reinforcing member MPT is attached to the protection member BPT, the protection member UVR does not bend at the end EU11.

[0051] Fig. 6 is a cross-sectional view of a display device of another comparative example. The display device DSP shown in Fig. 6 is different from the display device DSP shown in Fig. 4 in that it is not provided with a polarizing plate POL.

[0052] In the display device DSP shown in Fig. 6, a color filter is provided on the array substrate side (substrate SUB1) of the display panel PNL. Therefore, the display device DSP shown in Fig. 6 does not need to be provided with a polarizing plate.

[0053] Also in FIG. 6, since the reinforcing member MPT is attached to the protection member BPT, the protection member UVR does not bend at the end EU11.

[0054] When the display device DSP is bent as shown in Figure 2, tensile stress is generated on the convex side of the neutral plane (neutral axis) of the bent region BND according to the distance from the neutral plane. On the concave side of the neutral plane (neutral axis) of the region BND, compressive stress is generated according to the distance from the neutral plane.

[0055] However, if the protective member UVR is made of a material that undergoes plastic deformation, this has almost no effect on the neutral plane control of the region BND. If the protective member UVR is made of a material that undergoes elastic deformation, such as a polyimide resin material or an acrylic resin material, instead of a material that undergoes plastic deformation, then neutral plane control of the region BND is possible.

[0056] Elasticity is the property of being deformed when stress is applied and returning to its original shape when the stress is removed. Elastic deformation is deformation that returns to its original shape when the stress is removed. On the other hand, plasticity is the property of being deformed when stress is applied and not returning to its original shape even when the stress is removed. Plastic deformation is deformation that does not return to its original shape even when the stress is removed.

[0057] If the protective member UVR is made of a material that undergoes plastic deformation, when stress is applied to the protective member UVR and the protective member UVR is deformed, the protective member UVR does not return to its original shape even when the stress is removed. Therefore, in the display device DSP that is bent at the region BND, a neutral surface is generated within the components other than the protective member UVR.

[0058] If the protective member UVR is made of an elastically deformable material, even if the protective member UVR is deformed by the application of stress, the protective member UVR will return to its original shape when the stress is removed. Therefore, in the display device DSP folded at the region BND, a neutral surface is generated within the components including the protective member UVR.

[0059] However, if the protective member UVR is made of an elastically deformable material such as a polyimide resin material, a gap may occur between the polarizing plate POL and the protective member UVR. If such a gap occurs, there is a risk that the protective member UVR may bend at the end EU11, as described above.

[0060] In order to prevent a gap from occurring between the polarizing plate POL and the protective member UVR, it is preferable that the protective member UVR is made of a material having plasticity. If the material has plasticity, once it is deformed, it will not return to its original shape, so the protective member UVR will not peel off from the polarizing plate POL. Therefore, in consideration of the adhesion with the polarizing plate POL, it is preferable that the protective member UVR is made of a material that undergoes plastic deformation rather than an elastically deformable material.

[0061] However, if the protective member UVR is made of a material that undergoes plastic deformation, as described above, the protective member UVR does not affect the neutral plane NS. In that case, the neutral plane NS may be generated in an undesired location. This will be explained below.

[0062] 7 is a partially enlarged cross-sectional view of the bent region BND. In FIG. 7, of the surfaces of the base material BA1, the insulating layer BPLN, the lead wiring LW, the insulating layer PLN, and the protective member UVR, the surface disposed on the lower side is referred to as the lower surface, and the surface disposed on the upper side is referred to as the upper surface.

[0063] Let the lower surface and the upper surface of the base material BA1 be the lower surface RBA and the upper surface FBA, respectively. Let the lower surface and the upper surface of the insulating layer BPLN be the lower surface RBP and the upper surface FBP, respectively. Let the lower surface and the upper surface of the lead-out wiring LW be the lower surface RLW and the upper surface FLW, respectively. Let the lower surface and the upper surface of the insulating layer PLN be the lower surface RPL and the upper surface FPL, respectively. Let the lower surface and the upper surface of the protection member UVR be the lower surface RVR and the upper surface FVR, respectively.

[0064] Along the third direction Z, let the distance from the lower surface RBA of the base material BA1 to the upper surface FBA be the length t1. The length t1 is the thickness of the base material BA1.

[0065] Along the third direction Z, let the distance from the lower surface RBA of the base material BA1 to the upper surface FBP of the insulating layer BPLN be the length t2. The length 2 is the sum of the thickness of the base material BA1 and the thickness of the insulating layer BPLN.

[0066] Along the third direction Z, let the distance from the lower surface RBA of the base material BA1 to the upper surface FLW of the lead-out wiring LW be the length t3. The length t3 is the sum of the thickness of the base material BA1, the thickness of the insulating layer BPLN, and the thickness of the lead-out wiring LW.

[0067] Along the third direction Z, let the distance from the lower surface RBA of the base material BA1 to the upper surface FPL of the insulating layer PLN be the length t4. The length t4 is the sum of the thickness of the base material BA1, the thickness of the insulating layer BPLN, the thickness of the lead-out wiring LW, and the thickness of the insulating layer PLN.

[0068] When calculating the neutral plane NS (neutral axis) of the region BND, it can be found that it exists inside the base material BA1. Along the third direction Z, let the distance from the lower surface RBA of the base material BA1 to the neutral plane NS be the length tn. The length tn is smaller than the length t1 (tn < t1). The protection member UVR is formed of a material that plastically deforms as described above and has no influence on the neutral plane NS.

[0069] A compressive stress acts on a part of the base material BA1 disposed below the neutral plane NS, and a tensile stress acts on another part of the base material BA1 disposed above the neutral plane NS, the insulating layer BPLN, the leader wiring LW, and the insulating layer PLN.

[0070] 7, a neutral plane NS is generated in the substrate BA1. Therefore, a tensile stress acts on the lead wiring LW disposed above the neutral plane NS, and the lead wiring LW may be broken due to the tensile stress.

[0071] 8 and 9 are diagrams showing the relationship between the radius of curvature and the distance from the lower surface of the substrate to the neutral plane when the display device of the comparative example is folded. In Fig. 8, the horizontal axis is the radius of curvature R (mm) of the folded display device. In Fig. 9, the horizontal axis is the radius of curvature R (mm) of the folded display device. The vertical axis of Figs. 8 and 9 is the distance L (μm) from the lower surface RBA of the substrate BA1 to the neutral plane NS along the third direction Z. Fig. 8 is a partially enlarged view of Fig. 9.

[0072] Plot SMP0 is a plot of a laminate structure of the display device DSP of the comparative example that does not include the protective member UVR. Plots SMP1, SMP2, and SMP3 are plots of laminate structures in which the protective member UVR has a thickness of 100 μm, 200 μm, and 300 μm, respectively.

[0073] As shown in Figure 8, in plot SMP1, elastic deformation occurs up to a radius of curvature R of 70 mm, but when the radius of curvature R exceeds 70 mm, plastic deformation occurs. In other words, the yield point YP1 occurs at a radius of curvature R of 70 mm. The distance L when elastic deformation occurs is 19 (μm).

[0074] In plot SMP0, no elastic or plastic deformation occurs.

[0075] In plots SMP2 and SMP3, the yield points (yield point YP2 and yield point YP3) occur when the radius of curvature R is approximately 100 mm.

[0076] When bending with a curvature radius R of 1 mm or less, plots SMP1 (thickness of UVR protective material 100 μm) to SMP3 (thickness of UVR protective material 300 μm) all converge to the same neutral plane position as plot SMP0 (no UVR protective material). Therefore, it can be said that the UVR protective material has no effect on neutral plane control.

[0077] By providing an elastically deformable material layer above or below the lead-out wiring LW and adjusting the thickness of the elastically deformable material layer so that a neutral plane is generated in the lead-out wiring LW, it is possible to prevent the lead-out wiring LW from being broken due to stress. The position of the neutral plane can be appropriately changed depending on the material of the substrate BA1, the material of the elastically deformable material layer, etc.

[0078] In the display device of this embodiment, the thickness of the insulating layer PLN formed on the lead-out wiring LW is increased in order to generate a neutral surface in the lead-out wiring LW. When the neutral surface is generated in the lead-out wiring LW, almost no stress acts on the lead-out wiring LW, and it is possible to prevent disconnection of the lead-out wiring LW.

[0079] In addition, since the insulating layer PLN is a layer formed during the manufacturing process of the array substrate (substrate SUB1), neutral plane control is possible without increasing the number of manufacturing processes. If the insulating layer PLN is, for example, a polyimide or acrylic resin insulating layer as described above, there is no effect of heat on the thin film transistor (TFT) provided in the pixel PX.

[0080] Fig. 10 is a diagram showing the relationship between the radius of curvature and the distance from the bottom surface of the base material to the neutral plane when the display device of the embodiment is folded. The display device DSP shown in Fig. 10 is provided with a thick insulating layer PLN instead of the protective member UVR, as compared with the display device DSP shown in Fig. 7.

[0081] As described above, the insulating layer PLN is formed of a material that elastically deforms. Therefore, a neutral plane NS occurs in the laminated structure of the base material BA1, the insulating layer BPLN, the lead-out wiring LW, and the insulating layer PLN. By controlling the thickness th of the insulating layer PLN, the length t4 from the lower surface RBA of the base material BA1 to the upper surface FPL of the insulating layer PLN can be controlled. The length t4 is adjusted so that the neutral plane NS occurs in the lead-out wiring LW.

[0082] FIG. 11 is a cross-sectional view showing an example of a schematic configuration of the display device according to the embodiment. In the display device DSP shown in FIG. 11, a thick region PP is provided in a part of the insulating layer PLN. The protective member UVR is provided between the region PP and the flexible wiring board FPC1.

[0083] As described above, a thick region PP is provided so as to overlap with a region BND that is a part of the insulating layer PLN and is a bending region. Among the insulating layer PLN, a region other than the region PP is defined as a region MSG. Along the third direction Z, the distance from the lower surface RPL of the insulating layer PLN to the upper surface FPL1 of the region MSG is defined as a length tf. Along the third direction Z, the distance from the lower surface RPL of the insulating layer PLN to the upper surface FPL2 of the region PP is defined as a length tp. The length tf and the length tp are the film thicknesses of the region MSG and the region PP, respectively. The length tf is smaller than the length tp (tf < tp). The length tp shown in FIG. 11 corresponds to the thickness th shown in FIG. 10.

[0084] Among the ends of the region PP, the end close to the end EF11 of the flexible wiring board FPC1 is defined as an end EN12. Among the ends of the region PP, the end on the side opposite to the end EN12 in the direction opposite to the second direction Y is defined as an end EN11.

[0085] When the length tp (thickness) of the region PP is 25 μm, the length tn from the lower surface RBA of the base material BA1 to the neutral plane NS is 17.75 μm. At this time, the neutral plane NS occurs in the lead-out wiring LW. Therefore, almost no stress is applied to the lead-out wiring LW.

[0086] The display device DSP shown in Fig. 11 also has a protection member UVR. However, it is disposed outside the region BND, which is the bending region. Therefore, the protection member UVR does not contribute to neutral plane control.

[0087] In this embodiment, instead of providing the protective member UVR after the array substrate is created, the insulating layer PLN is partially thickened during the creation of the array substrate. The insulating layer PLN is made of an elastically deformable material. This creates a neutral plane NS on the lead-out wiring LW. Therefore, no stress is applied to the lead-out wiring LW, and there is no risk of breakage. This makes it possible to suppress a decrease in the manufacturing yield of the display device DSP.

[0088] Here, the pixels PX of the display panel PNL will be explained in more detail.

[0089] 12 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.

[0090] FIG. 13 is a cross-sectional view taken along line A1-A2 of the display panel shown in FIG. The base material BA1 may be a base material made of a resin film material, as described above. Examples of the resin film material include acrylic, polyimide, polyethylene terephthalate, polyethylene naphthalate, etc., and may be formed as a single layer or a laminate of multiple layers.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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).

[0095] 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 silicon oxide or silicon nitride.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] The insulating layer PLL shown in Fig. 13 corresponds to the insulating layer BPLN shown in Fig. 11. The insulating layer SEY shown in Fig. 13 corresponds to the insulating layer PLN shown in Fig. 11. When the insulating layer SEY is formed of an insulating layer in which an organic insulating layer is sandwiched between two inorganic insulating layers, the length tp (thickness) of the region PP can be controlled by controlling the film thickness of the organic insulating layer.

[0111] 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.

[0112] 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]

[0113] BND...area, BPLN...insulating layer, DSP...display device, EA...area, LW...lead wiring, NS...neutral plane, PLN...insulating layer, PNL...display panel, SUB1...substrate.

Claims

1. A flexible substrate; A first insulating layer provided on the substrate; A wiring provided on the first insulating layer; a second insulating layer covering the wiring and the first insulating layer; A display device comprising: The display device has a display region and an end region having a folding region, the second insulating layer has a first region having a first thickness and a second region having a second thickness greater than the first thickness; The second region overlaps the folding region, A display device, wherein a neutral plane of a laminated structure of the base material, the first insulating layer, the wiring, and the second insulating layer occurs in the wiring.

2. The display device according to claim 1 , wherein the second insulating layer is made of an elastically deformable material.

3. The display device according to claim 2 , wherein the elastically deformable material is a resin insulating material such as polyimide or acrylic.

4. The display device according to claim 1 , wherein the base material is a resin film material selected from the group consisting of acrylic, polyimide, polyethylene terephthalate, and polyethylene naphthalate.

5. The display device according to claim 1 , wherein the first insulating layer is made of an elastically deformable material.

6. The display device according to claim 5 , wherein the elastically deformable material is a resin insulating material such as polyimide or acrylic.

7. 2. The display device according to claim 1, wherein the wiring is formed of a single layer or a multilayer of titanium (Ti), aluminum (Al), tantalum (Ta), tungsten (W), molybdenum (Mo), copper (Cu), or silver (Ag).

8. a plurality of pixels disposed within the display area; The display device according to claim 1 , wherein each of the plurality of pixels has an organic electroluminescence layer.

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