Display device

Abstract

The present invention provides a display device capable of suppressing breakage of a display panel and suppressing bending of the display panel in a state where the display panel is unfolded. The display device (10) includes: a display panel (20) that can be wound; and a cover member (30) laminated on the display panel (20) and capable of being wound together with the display panel (20). When the display panel (20) is wound, the heat shrinkage rate of the cover member (30) in the bending direction (A) in which the display panel (20) bends is smaller than the heat shrinkage rate of the cover member (30) in the orthogonal direction (B) orthogonal to the bending direction (A).

Description

Technical Field

[0001] The present invention relates to a display device, and more particularly to a display device including a flexible display panel. Background Art

[0002] Conventionally, a display device including a flexible display panel has been known. As an example of such a display device, a foldable display in which a polyester film for protecting an organic EL module is disposed is disclosed in Patent Document 1.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-197705

[0004] However, the foldable display of Patent Document 1 has the following problems: the polyester film for protecting the organic EL module is likely to thermally shrink along the bending direction of the organic EL module, and in a state where the organic EL module is unfolded, the organic EL module is bent due to the thermal shrinkage of the polyester film for protecting the organic EL module. In addition, in a conventional display device including a display panel that can be wound, the following problem exists: a cover member for protecting the display panel is likely to thermally shrink along the bending direction of the display panel, and in a state where the display panel is unfolded, the display panel is bent due to the thermal shrinkage of the cover member. In order to suppress the bending of the display panel, it is possible to consider strongly pulling the display panel, but if the display panel is strongly pulled, the display panel is likely to be damaged. Summary of the Invention

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a display device that can suppress damage to a display panel and can suppress bending of the display panel in a state where the display panel is unfolded.

[0006] A display device according to one aspect of the present invention includes: a display panel that can be wound or bent; and a cover member that is laminated on the display panel and can be wound or bent together with the display panel, and the display device satisfies the following (1) or (2): (1) the thermal shrinkage rate of the cover member in the bending direction in which the display panel bends when the display panel is wound is smaller than the thermal shrinkage rate of the cover member in the orthogonal direction orthogonal to the bending direction, (2) the thermal shrinkage rate of the cover member in the bending direction in which the display panel bends when the display panel is bent is smaller than the thermal shrinkage rate of the cover member in the orthogonal direction orthogonal to the bending direction.

[0007] In addition, a display device according to one aspect of the present invention includes: a display panel that can be wound or bent; a cover member laminated on the display panel and capable of being wound or bent together with the display panel; and a circular polarizing plate laminated between the display panel and the cover member and capable of being wound or bent together with the display panel, wherein the cover member does not thermally shrink, and the display device satisfies the following (1) or (2): (1) When the display panel is wound, the thermal shrinkage rate of the circular polarizing plate in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the circular polarizing plate in the orthogonal direction orthogonal to the bending direction. (2) When the display panel is bent, the thermal shrinkage rate of the circular polarizing plate in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the circular polarizing plate in the orthogonal direction orthogonal to the bending direction.

[0008] According to the present invention, it is possible to provide a display device that can suppress breakage of the display panel and can suppress bending of the display panel in a state where the display panel is unfolded. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 FIGS. (a) and (b) are perspective views showing the display device of Embodiment 1.

[0010] Figure 2 It shows Figure 1 exploded perspective view of the display device of FIG. (a).

[0011] Figure 3 It is an exploded perspective view showing the display device of Embodiment 2.

[0012] Figure 4 It shows Figure 3 cross-sectional view of the display device.

[0013] Figure 5 It is an exploded perspective view showing the display device of Embodiment 3.

[0014] Figure 6 FIGS. (a) and (b) are perspective views showing the display device of Embodiment 4.

[0015] Figure 7 It shows Figure 6 exploded perspective view of the display device of FIG. (a).

[0016] Figure 8 FIGS. (a) to (h) are diagrams showing the experimental results regarding wrinkles of the display panel and the like.

[0017] REFERENCE MARK DESCRIPTION

[0018] 10, 10a, 10b, 10c display device

[0019] 20, 20c Display panel

[0020] 21, 21c Display surface

[0021] 30, 30b, 30c Cover member

[0022] 40, 40c Circular polarizing plate

[0023] 41 Polarizer

[0024] 50 Retardation plate

[0025] 60 Optical adhesive sheet Detailed implementation mode

[0026] Hereinafter, an implementation mode of the display device of the present invention will be described with reference to the accompanying drawings. In addition, all the implementation modes described below represent a specific example of the present invention. Therefore, the numerical values, constituent elements, arrangement positions of the constituent elements, connection methods, etc. shown in the following implementation modes are examples and do not limit the gist of the present invention. Therefore, regarding the constituent elements in the following implementation modes that are not described in the independent technical solutions, they can be described as arbitrary constituent elements.

[0027] In each figure, the same reference numerals are added to substantially the same constituent elements. In addition, each figure is a schematic diagram and does not necessarily strictly represent the size ratio of each part, etc.

[0028] (Embodiment 1)

[0029] Figure 1 Figures (a) and (b) are perspective views showing the display device 10 of Embodiment 1. Figure 1 Figure (a) shows a state where the display panel 20 etc. of the display device 10 are unfolded, Figure 1 Figure (b) shows a state where the display panel 20 etc. of the display device 10 are wound. Figure 2 It shows Figure 1 The exploded perspective view of the display device 10 of Figure (a). Refer to Figure 1 Figures (a) and (b) and Figure 2 The display device 10 of Embodiment 1 will be described.

[0030] As Figure 1 Figures (a) and (b) and Figure 2 shown, the display device 10 is a device for displaying images, and includes a display panel 20, a cover member 30, and a circular polarizing plate 40. The display device 10 is a rollable display device that can wind the display panel 20, the cover member 30, and the circular polarizing plate 40 and can unfold the wound display panel 20 etc. For example, the display device 10 is used for a flat panel terminal, a digital TV, a digital signage, a smart phone, or a wearable terminal, etc.

[0031] The display panel 20 is a display panel that can be wound. The display panel 20 is flexible and is a so-called flexible display panel. The display panel 20 displays images. For example, the display panel 20 is connected to a driving substrate (not shown) through a flexible substrate (not shown), and is driven by the driving substrate to display images. The display panel 20 has a display surface 21 for displaying images.

[0032] The display panel 20 is a plate-shaped member that extends in a first direction and a second direction orthogonal to the first direction in an unfolded state, and has a third direction orthogonal to the first direction and orthogonal to the second direction as the thickness direction, and displays images on one side facing the third direction (the positive side of the Z-axis direction). When viewed from the third direction in the unfolded state, the display panel 20 is rectangular. The first direction is the direction represented by the X-axis in (a) and (b) etc. Figure 1 The second direction is the direction represented by the Y-axis in (a) and (b) etc., and the third direction is the direction represented by the Z-axis in (a) and (b) etc. In addition, for example, in the unfolded state, the display panel 20 may not be rectangular, and may be other polygons, circles, ellipses, etc. Figure 1 The second direction is the direction represented by the Y-axis in (a) and (b) etc., and the third direction is the direction represented by the Z-axis in (a) and (b) etc. In addition, for example, in the unfolded state, the display panel 20 may not be rectangular, and may be other polygons, circles, ellipses, etc. Figure 1 The second direction is the direction represented by the Y-axis in (a) and (b) etc., and the third direction is the direction represented by the Z-axis in (a) and (b) etc. In addition, for example, in the unfolded state, the display panel 20 may not be rectangular, and may be other polygons, circles, ellipses, etc.

[0033] The display panel 20 is wound around the first direction. That is, the display panel 20 bends around the first direction in the wound state. In the present embodiment, the display panel 20 is wound in such a manner that the cover member 30 and the circularly polarized light plate 40 are located more internally than the display panel 20.

[0034] When the display panel 20 is wound, the bending direction A in which the display panel 20 bends is a direction parallel to the main surface (such as the display surface 21) of the display panel 20, coincides with the second direction in the unfolded state of the display panel 20, and bends around the first direction in the wound state of the display panel 20.

[0035] The orthogonal direction B orthogonal to the bending direction A is a direction parallel to the main surface (such as the display surface 21) of the display panel 20, and coincides with the first direction.

[0036] For example, the display panel 20 is an OLED (Organic Light Emitting Diode) panel, and is formed by laminating a TFT (Thin Film Transistor), an OLED having an organic EL element, and a TFE (Thin Film Encapsulation).

[0037] The cover member 30 is laminated on the display panel 20 and can be wound together with the display panel 20. The cover member 30 is laminated on the display surface 21 side of the display panel 20 and is arranged to cover the display panel 20 and the circularly polarized light plate 40. The cover member 30 allows the light emitted from the display panel 20 to pass through. The cover member 30 has flexibility.

[0038] The cover member 30 is a plate-like member that extends in the first direction and the second direction and has the third direction as the thickness direction in the unfolded state. The cover member 30 is rectangular when viewed from the third direction in the unfolded state. Additionally, for example, the cover member 30 may not be rectangular in the unfolded state and may be other polygons, circles, ellipses, etc.

[0039] The thermal shrinkage rate of the cover member 30 in the bending direction A is smaller than the thermal shrinkage rate of the cover member 30 in the orthogonal direction B. That is, the cover member 30 is laminated on the display panel 20 in such a manner that the thermal shrinkage rate of the cover member 30 in the bending direction A is smaller than the thermal shrinkage rate of the cover member 30 in the orthogonal direction B. For example, when the cover member 30 thermally shrinks in each of two directions C and D that are parallel to the main surface of the cover member 30 and orthogonal to each other, the cover member 30 is laminated on the display panel 20 in such a manner that the direction C with a smaller thermal shrinkage rate of the cover member 30 among these two directions C and D coincides with the bending direction A.

[0040] In the present embodiment, the direction C is the direction in which the thermal shrinkage rate of the cover member 30 is the smallest, and the cover member 30 is laminated on the display panel 20 in such a manner that the direction C with the smallest thermal shrinkage rate of the cover member 30 coincides with the bending direction A. That is, in the present embodiment, the direction C with the smallest thermal shrinkage rate of the cover member 30 coincides with the bending direction A. For example, when the cover member 30 thermally shrinks in each of a plurality of directions that are parallel to the main surface of the cover member 30 and cross each other, the cover member 30 is laminated on the display panel 20 in such a manner that the direction C with the smallest thermal shrinkage rate of the cover member 30 among these plurality of directions coincides with the bending direction A.

[0041] For example, the cover member 30 is bonded to the circularly polarized light plate 40 via an optical adhesive sheet (not shown). For example, as the optical adhesive sheet, an acrylic-based, silicone-based, epoxy-based, or rubber-based adhesive can be used. For example, the cover member 30 is formed using polyethylene terephthalate (PET) having a hard coat (HC). For example, the cover member 30 may be a single layer or a laminated structure obtained by laminating different materials.

[0042] The circularly polarized light plate 40 is laminated between the display panel 20 and the cover member 30 and can be wound together with the display panel 20. The circularly polarized light plate 40 is laminated on the display surface 21 side of the display panel 20 and is arranged to cover the display panel 20. The circularly polarized light plate has a structure in which a retardation plate is laminated on a polarizing plate. For example, the circularly polarized light plate 40 functions to suppress reflection of external light from the panel surface and improve the contrast of the displayed image. The circularly polarized light plate 40 is flexible.

[0043] The circularly polarized light plate 40 is a plate-like member that extends in the first direction and the second direction in the unfolded state and has the third direction as the thickness direction. When the circularly polarized light plate 40 is viewed from the third direction in the unfolded state, it is rectangular. In addition, for example, the circularly polarized light plate 40 may not be rectangular in the unfolded state and may be other polygons, circles, ellipses, etc.

[0044] The thermal shrinkage rate of the circularly polarized light plate 40 in the bending direction A is smaller than the thermal shrinkage rate of the circularly polarized light plate 40 in the orthogonal direction B. That is, the circularly polarized light plate 40 is laminated between the display panel 20 and the cover member 30 in such a manner that the thermal shrinkage rate of the circularly polarized light plate 40 in the bending direction A is smaller than the thermal shrinkage rate of the circularly polarized light plate 40 in the orthogonal direction B. For example, when the circularly polarized light plate 40 thermally shrinks in each of two directions E and F that are parallel to the main surface of the circularly polarized light plate 40 and orthogonal to each other, the circularly polarized light plate 40 is laminated on the display panel 20 in such a manner that the direction E with a smaller thermal shrinkage rate of the circularly polarized light plate 40 among these two directions E and F coincides with the bending direction A.

[0045] In the present embodiment, the direction E is the direction in which the thermal shrinkage rate of the circularly polarized light plate 40 is the smallest, and the circularly polarized light plate 40 is laminated between the display panel 20 and the cover member 30 in such a manner that the direction E with the smallest thermal shrinkage rate of the circularly polarized light plate 40 coincides with the bending direction A. That is, in the present embodiment, the direction E with the smallest thermal shrinkage rate of the circularly polarized light plate 40 coincides with the bending direction A. For example, when the circularly polarized light plate 40 thermally shrinks in each of a plurality of directions that are parallel to the main surface of the circularly polarized light plate 40 and cross each other, the circularly polarized light plate 40 is laminated between the display panel 20 and the cover member 30 in such a manner that the direction E with the smallest thermal shrinkage rate of the circularly polarized light plate 40 among these plurality of directions coincides with the bending direction A.

[0046] For example, the circularly polarized light plate 40 is bonded to the display panel 20 via an optical adhesive sheet (not shown). For example, as the optical adhesive sheet, an acrylic-based, silicone-based, epoxy-based, or rubber-based adhesive can be used.

[0047] The display device 10 of Embodiment 1 has been described above.

[0048] The display device 10 according to Embodiment 1 includes: a display panel 20 that can be wound; and a cover member 30 that is laminated on the display panel 20 and can be wound together with the display panel 20, and when the display panel 20 is wound, the heat shrinkage rate of the cover member 30 in the bending direction A in which the display panel 20 bends is smaller than the heat shrinkage rate of the cover member 30 in the orthogonal direction B orthogonal to the bending direction A.

[0049] Accordingly, since the heat shrinkage of the cover member 30 in the bending direction A can be suppressed, the bending of the display panel 20 caused by the heat shrinkage of the cover member 30 in the bending direction A can be suppressed. Therefore, since the bending of the display panel 20 can be suppressed without strongly pulling the display panel 20, the breakage of the display panel 20 can be suppressed, and the bending of the display panel 20 in the unfolded state of the display panel 20 can be suppressed.

[0050] In addition, in the display device 10 according to Embodiment 1, the cover member 30 is laminated on the display panel 20 such that the direction C with the minimum heat shrinkage rate of the cover member 30 coincides with the bending direction A.

[0051] Accordingly, since the heat shrinkage of the cover member 30 in the bending direction A can be further suppressed, the breakage of the display panel 20 can be suppressed, and the bending of the display panel 20 in the unfolded state of the display panel 20 can be further suppressed.

[0052] In addition, the display device 10 according to Embodiment 1 further includes a circularly polarized light plate 40 that is laminated between the display panel 20 and the cover member 30 and can be wound together with the display panel 20, and the heat shrinkage rate of the circularly polarized light plate 40 in the bending direction A is smaller than the heat shrinkage rate of the circularly polarized light plate 40 in the orthogonal direction B.

[0053] Accordingly, since the heat shrinkage of the circularly polarized light plate 40 in the bending direction A can be suppressed, the bending of the display panel 20 caused by the heat shrinkage of the circularly polarized light plate 40 in the bending direction A can be suppressed. Therefore, since the bending of the display panel 20 can be further suppressed without strongly pulling the display panel 20, the breakage of the display panel 20 can be suppressed, and the bending of the display panel 20 in the unfolded state of the display panel 20 can be further suppressed.

[0054] In addition, in the display device 10 according to Embodiment 1, the circularly polarized light plate 40 is laminated between the display panel 20 and the cover member 30 such that the direction E with the minimum heat shrinkage rate of the circularly polarized light plate 40 coincides with the bending direction A.

[0055] Accordingly, since the heat shrinkage of the circularly polarized light plate 40 in the bending direction A can be further suppressed, the breakage of the display panel 20 can be suppressed, and the bending of the display panel 20 in the unfolded state of the display panel 20 can be further suppressed.

[0056] In addition, in the above-described Embodiment 1, the case where the thermal shrinkage rate of the circular polarizing plate 40 in the bending direction A is smaller than the thermal shrinkage rate of the circular polarizing plate 40 in the orthogonal direction B has been described, but it is not limited thereto. For example, the thermal shrinkage rate of the circular polarizing plate 40 in the bending direction A may also be larger than the thermal shrinkage rate of the circular polarizing plate 40 in the orthogonal direction B. The direction in which the thermal shrinkage rate of the cover member 30 is the smallest is important.

[0057] In addition, in the above-described Embodiment 1, the case where the display device 10 includes the display panel 20, the cover member 30, and the circular polarizing plate 40 has been described, but it is not limited thereto.

[0058] For example, the display device 10 may not include the circular polarizing plate 40.

[0059] In addition, for example, the display device 10 may further include: a winding device for winding the display panel 20 and the like; and a pulling-out device for pulling out the wound display panel 20 and the like. For example, the winding device includes: a core connected to one end of the display panel 20 and the like for winding the display panel 20 and the like; and a motor for rotating the core. In addition, for example, the pulling-out device includes: a fixing member fixed to the other end of the display panel 20 and the like; and a pantograph section for pushing the fixing member in the pulling-out direction. This is the same for Embodiment 2 and Embodiment 3 described later.

[0060] (Embodiment 2)

[0061] Figure 3 FIG. is an exploded perspective view showing the display device 10a of Embodiment 2. Figure 4 It shows Figure 3 A cross-sectional view of the display device 10a. Refer to Figure 3 And Figure 4 The display device 10a of Embodiment 2 will be described.

[0062] As Figure 3 And Figure 4 Shown, the main difference between the display device 10a and the display device 10 is that a polarizing film 41 and a retardation plate 50 are directly provided on the cover member 30, and the cover member 30, the polarizing film 41, and the retardation plate 50 are integrally formed. The polarizing film 41 mentioned here is a polarizing film obtained by impregnating PVA (polyvinyl alcohol) into a polyiodide compound or a dye and stretching it in one direction. In the present embodiment, the configuration of the circular polarizing plate includes the polarizing film 41 and the retardation plate 50. That is, in the present embodiment, the cover member 30 and the circular polarizing plate (the polarizing film 41 and the retardation plate 50) are integrally formed with each other.

[0063] The cover member 30 and the polarizing plate 41 are integrally formed with each other. For example, the cover member 30 and the polarizing plate 41 are directly bonded to each other in the circularly polarized light plate manufacturing process, and are integrally formed with each other without passing through an optical adhesive sheet.

[0064] The retardation plate 50 is provided so that light entering from the outside is reflected by the display panel 20 and does not transmit to the outside. The retardation plate 50 is laminated between the display panel 20 and the polarizing plate 41. The retardation plate 50 and the polarizing plate 41 are integrally formed with each other. For example, the retardation plate 50 and the polarizing plate 41 are joined using a 5-μm thin adhesive material or a thin adhesive member of about 1 μm.

[0065] The lower surface of the retardation plate 50 is bonded to the display panel 20 via an optical adhesive sheet 60. For example, as the optical adhesive sheet 60, an acrylic-based, silicone-based, epoxy-based, or rubber-based adhesive can be used.

[0066] The display device 10a of the second embodiment has been described above.

[0067] In the display device 10a of the second embodiment, the cover member 30 and the circularly polarized light plate (polarizing plate 41 and retardation plate 50) are integrally formed with each other.

[0068] Accordingly, since it is not necessary to provide the optical adhesive sheet 60 below the cover member 30, it is possible to achieve a single layer, and by minimizing the influence of thermal shrinkage, it is possible to suppress the bending of the display panel 20. Therefore, it is possible to suppress breakage of the display panel 20, and it is possible to further suppress the bending of the display panel 20 in the state where the display panel 20 is unfolded. It is also possible to suppress the bending deformation when the cover member is bent inward in the direction where the thermal shrinkage of the cover member is small.

[0069] (Embodiment 3)

[0070] Figure 5 is an exploded perspective view showing the display device 10b of the third embodiment. Refer to Figure 5 The display device 10b of the third embodiment will be described.

[0071] As Figure 5 shown, the display device 10b mainly differs from the display device 10 in that it includes a cover member 30b instead of the cover member 30.

[0072] The cover member 30b is laminated on the display panel 20 and can be wound together with the display panel 20. The cover member 30b is mainly different from the cover member 30 in that it does not thermally shrink. The cover member 30b is formed of a material that does not thermally shrink. For example, the cover member 30b is formed of glass such as Ultra Thin Glass (UTG). For example, the cover member 30b is bonded to the circularly polarized light plate 40 using an optical adhesive sheet (not shown). For example, the thickness of the cover member 30b is 70 μm.

[0073] As described above, the display device 10b of Embodiment 3 has been described.

[0074] The display device 10b of Embodiment 3 includes: a display panel 20 that can be wound; a cover member 30b that is laminated on the display panel 20 and can be wound together with the display panel 20; and a circularly polarized light plate 40 that is laminated between the display panel 20 and the cover member 30b and can be wound together with the display panel 20. The cover member 30b does not thermally shrink, and the thermal shrinkage rate of the circularly polarized light plate 40 in the bending direction A in which the display panel 20 bends when the display panel 20 is wound is smaller than the thermal shrinkage rate of the circularly polarized light plate 40 in the orthogonal direction B orthogonal to the bending direction A.

[0075] Accordingly, since the cover member 30b does not thermally shrink, bending of the display panel 20 due to thermal shrinkage of the cover member 30b can be suppressed. In addition, since thermal shrinkage of the circularly polarized light plate 40 in the bending direction A can be suppressed, bending of the display panel 20 due to thermal shrinkage of the circularly polarized light plate 40 in the bending direction A can be suppressed. Therefore, bending of the display panel 20 can be suppressed without strongly pulling the display panel 20, so that breakage of the display panel 20 can be suppressed, and bending of the display panel 20 in the unfolded state of the display panel 20 can be suppressed.

[0076] (Embodiment 4)

[0077] Figure 6 (a) and (b) of are perspective views showing the display device 10c of Embodiment 4. Figure 6 (a) of shows a state in which the display panel 20c of the display device 10c is unfolded, Figure 6 (b) of shows a state in which the display panel 20c of the display device 10c is bent. Figure 7 is a perspective view showing Figure 6 (a) of the display device 10c. Refer to Figure 6 (a) and (b) of and Figure 7 to describe the display device 10c of Embodiment 4.

[0078] As shown in Figure 6 (a) and (b) of and Figure 7As shown, the display device 10c is a device that displays images, and includes a display panel 20c, a cover member 30c, and a circularly polarizing plate 40c. The display device 10c is a foldable display device that can fold the display panel 20c, the cover member 30c, and the circularly polarizing plate 40c and can unfold the folded display panel 20c and the like. For example, the display device 10c is used for a tablet terminal, a digital TV, a digital signage, a smart phone, or a wearable terminal, etc.

[0079] The display panel 20c is a display panel that can be bent. The display panel 20c has flexibility and is a so-called flexible display panel. The display panel 20c displays images. For example, the display panel 20c is connected to a driving substrate (not shown) via a flexible substrate (not shown) and is driven by the driving substrate to display images. The display panel 20c has a display surface 21c for displaying images.

[0080] The display panel 20c is a plate-like member that extends in a first direction and a second direction and has a third direction as a thickness direction in an unfolded state, and displays images toward one side in the third direction (the positive side in the Z-axis direction). The display panel 20c is rectangular when viewed from the third direction in an unfolded state. In addition, for example, the display panel 20c may not be rectangular in an unfolded state and may be other polygons, a circle, an ellipse, etc.

[0081] The display panel 20c is bent around the first direction. That is, the display panel 20c is bent around the first direction in a bent state. In the present embodiment, the display panel 20c is bent in such a manner that the cover member 30c and the circularly polarizing plate 40c are more inside than the display panel 20c.

[0082] When the display panel 20c is bent, the bending direction A1 in which the display panel 20c is bent is a direction parallel to the main surface (such as the display surface 21c) of the display panel 20c, coincides with the second direction in an unfolded state of the display panel 20c, and is bent around the first direction in a bent state of the display panel 20c.

[0083] The orthogonal direction B1 orthogonal to the bending direction A1 is a direction parallel to the main surface (such as the display surface 21c) of the display panel 20c and coincides with the first direction.

[0084] For example, the display panel 20c is an OLED (Organic Light Emitting Diode) panel and is formed by laminating a TFT (Thin Film Transistor), an OLED having an organic EL element, and a TFE (Thin Film Encapsulation).

[0085] The cover member 30c is laminated on the display panel 20c and can be bent together with the display panel 20c. The cover member 30c is laminated on the display surface 21c side of the display panel 20c so as to cover the display panel 20c and the circularly polarized light plate 40c. The cover member 30c allows the light emitted from the display panel 20c to pass through. The cover member 30c has flexibility.

[0086] The cover member 30c is a plate-like member that extends in the first direction and the second direction in the unfolded state and has the third direction as the thickness direction. When viewed from the third direction in the unfolded state, the cover member 30c is rectangular. In addition, for example, the cover member 30c may not be rectangular in the unfolded state and may be other polygons, circles, ellipses, etc.

[0087] The thermal shrinkage rate of the cover member 30c in the bending direction A1 is smaller than the thermal shrinkage rate of the cover member 30c in the orthogonal direction B1. That is, the cover member 30c is laminated on the display panel 20c in such a manner that the thermal shrinkage rate of the cover member 30c in the bending direction A1 is smaller than the thermal shrinkage rate of the cover member 30c in the orthogonal direction B1. For example, when the cover member 30c thermally shrinks in each of two directions C1 and D1 that are parallel to the main surface of the cover member 30c and orthogonal to each other, the cover member 30c is laminated on the display panel 20c in such a manner that the direction C1 with the smaller thermal shrinkage rate of the cover member 30c in these two directions C1 and D1 coincides with the bending direction A1.

[0088] In the present embodiment, the direction C1 is the direction in which the thermal shrinkage rate of the cover member 30c is the smallest, and the cover member 30c is laminated on the display panel 20c in such a manner that the direction C1 with the smallest thermal shrinkage rate of the cover member 30c coincides with the bending direction A1. That is, in the present embodiment, the direction C1 with the smallest thermal shrinkage rate of the cover member 30c coincides with the bending direction A1. For example, when the cover member 30c thermally shrinks in each of a plurality of directions that are parallel to the main surface of the cover member 30c and cross each other, the cover member 30c is laminated on the display panel 20c in such a manner that the direction C1 with the smallest thermal shrinkage rate of the cover member 30c in these plurality of directions coincides with the bending direction A1.

[0089] For example, the cover member 30c is bonded to the circularly polarized light plate 40c via an optical adhesive sheet (not shown). For example, as the optical adhesive sheet, an acrylic-based, silicone-based, epoxy-based, or rubber-based adhesive can be used. For example, the cover member 30c is formed using polyethylene terephthalate (PET) having a hard coat (HC).

[0090] The circularly polarized light plate 40c is laminated between the display panel 20c and the cover member 30c and can be bent together with the display panel 20c. The circularly polarized light plate 40c is laminated on the display surface 21c side of the display panel 20c and is arranged to cover the display panel 20c. The circularly polarized light plate 40c is flexible.

[0091] The circularly polarized light plate 40c is a plate-like member that extends in the first direction and the second direction in the unfolded state and has the third direction as the thickness direction. The circularly polarized light plate 40c is rectangular when viewed from the third direction in the unfolded state. Additionally, for example, the circularly polarized light plate 40c may not be rectangular in the unfolded state and may be other polygons, circles, ellipses, etc.

[0092] The thermal shrinkage rate of the circularly polarized light plate 40c in the bending direction A1 is smaller than the thermal shrinkage rate of the circularly polarized light plate 40c in the orthogonal direction B1. That is, the circularly polarized light plate 40c is laminated on the display panel 20c in such a manner that the thermal shrinkage rate of the circularly polarized light plate 40c in the bending direction A1 is smaller than the thermal shrinkage rate of the circularly polarized light plate 40c in the orthogonal direction B1. For example, when the circularly polarized light plate 40c shrinks thermally in each of two directions E1 and F1 that are parallel to the main surface of the circularly polarized light plate 40c and orthogonal to each other, the circularly polarized light plate 40c is laminated on the display panel 20c in such a manner that the direction E1 with the smaller thermal shrinkage rate of the circularly polarized light plate 40c among these two directions E1 and F1 coincides with the bending direction A1.

[0093] In the present embodiment, the direction E1 is the direction in which the thermal shrinkage rate of the circularly polarized light plate 40c is the smallest, and the circularly polarized light plate 40c is laminated between the display panel 20c and the cover member 30c in such a manner that the direction E1 with the smallest thermal shrinkage rate of the circularly polarized light plate 40c coincides with the bending direction A1. That is, in the present embodiment, the direction E1 with the smallest thermal shrinkage rate of the circularly polarized light plate 40c coincides with the bending direction A1. For example, when the circularly polarized light plate 40c shrinks thermally in each of a plurality of directions that are parallel to the main surface of the circularly polarized light plate 40c and cross each other, the circularly polarized light plate 40c is laminated between the display panel 20c and the cover member 30c in such a manner that the direction E1 with the smallest thermal shrinkage rate of the circularly polarized light plate 40c among these plurality of directions coincides with the bending direction A1.

[0094] For example, the circularly polarized light plate 40c is bonded to the display panel 20c via an optical adhesive sheet (not shown). For example, as the optical adhesive sheet, an acrylic-based, silicone-based, epoxy-based, or rubber-based adhesive can be used.

[0095] The display device 10c of the fourth embodiment has been described above.

[0096] The display device 10c according to Embodiment 4 includes: a display panel 20c that can be bent; and a cover member 30c that is laminated on the display panel 20c and can be bent together with the display panel 20c, and when the display panel 20c is bent, the heat shrinkage rate of the cover member 30c in the bending direction A1 in which the display panel 20c bends is smaller than the heat shrinkage rate of the cover member 30c in the orthogonal direction B1 orthogonal to the bending direction A1.

[0097] Accordingly, since the heat shrinkage of the cover member 30c in the bending direction A1 can be suppressed, the bending of the display panel 20c caused by the heat shrinkage of the cover member 30c in the bending direction A1 can be suppressed. Therefore, since the bending of the display panel 20c can be suppressed without strongly pulling the display panel 20c, breakage of the display panel 20c can be suppressed, and bending of the display panel 20c in the unfolded state of the display panel 20c can be suppressed.

[0098] In addition, in the above Embodiment 4, the case where the heat shrinkage rate of the circularly polarized light plate 40c in the bending direction A1 is smaller than the heat shrinkage rate of the circularly polarized light plate 40c in the orthogonal direction B1 has been described, but it is not limited thereto. For example, the heat shrinkage rate of the circularly polarized light plate 40c in the bending direction A1 may also be larger than the heat shrinkage rate of the circularly polarized light plate 40c in the orthogonal direction B1.

[0099] In addition, in the above Embodiment 4, the case where the display device 10c includes the display panel 20c, the cover member 30c, and the circularly polarized light plate 40c has been described, but it is not limited thereto. For example, the display device 10c may include a cover member that does not heat shrink and can be bent together with the display panel 20c, such as the cover member 30b, instead of the cover member 30c. In addition, for example, the display device 10c may not include the circularly polarized light plate 40c. It may be wound or bent in such a manner that the cover member 30c and the circularly polarized light plate 40c are located more outside than the display panel 20c.

[0100] Figure 8 (a) to (h) are diagrams showing the experimental results regarding the curling of the display panel and the like. Refer to Figure 8 The experimental results regarding the curling of the display panel and the like will be described with reference to (a) to (h).

[0101] Figure 8 (a) and (b) are the test results of Embodiment 2. They show the panel unit in the state of being unfolded after being wound into a ring with a radius of approximately 20 mm and placed in an environment of 95°C for 18 hours in the state where the panel unit is obtained by laminating the display panel and the circularly polarized light plate integrated with the cover member. Figure 8 (a) is the result of winding the panel unit in such a manner that the direction in which the heat shrinkage rate of the circularly polarized light plate becomes the minimum coincides with the bending direction of the display panel, Figure 8The result of winding the panel unit in such a way that the direction in which the thermal shrinkage rate of the circularly polarizing plate is minimized is orthogonal to the bending direction of the display panel.

[0102] For Figure 8 (a) and Figure 8 Comparing (b), it can be seen that: compared with Figure 8 (b), Figure 8 (a) has no wrinkles. Compared with the case where the direction in which the thermal shrinkage rate of the circularly polarizing plate is minimized is orthogonal to the bending direction of the display panel, when the direction in which the thermal shrinkage rate of the circularly polarizing plate is minimized is the same as the bending direction of the display panel, it is difficult to leave wrinkles.

[0103] Figure 8 (c) and Figure 8 (d) are the results of reproducing the test of Japanese Patent Laid-Open Publication No. 2020-197705 of the existing literature. It shows the cover member in the state after being unfolded after being placed in an environment of 95 °C for 18 hours in a state where only the cover member is wound into a ring with a radius of approximately 20 mm. Figure 8 (c) is the result of winding the cover member in such a way that the direction in which the thermal shrinkage rate of the cover member is minimized is the same as the bending direction of the cover member, Figure 8 (d) is the result of winding the cover member in such a way that the direction in which the thermal shrinkage rate of the cover member is minimized is orthogonal to the bending direction of the cover member.

[0104] For Figure 8 (c) and Figure 8 Comparing (d), it can be seen that: compared with Figure 8 (c), Figure 8 (d) has no wrinkles. When evaluating with the cover member alone, even if the thermal shrinkage rate is large, if it is bent in the direction with a small refractive index and elastic modulus, it is also difficult to leave wrinkles.

[0105] Figure 8 (e) and Figure 8 (g) show the panel unit in the state after being unfolded after being placed in an environment of 95 °C for 18 hours in a state where the panel unit obtained by sequentially laminating the display panel, the circularly polarizing plate, the optical adhesive sheet, and the cover member is wound into a ring with a radius of approximately 20 mm. Figure 8 (e) is the result of winding the panel unit in such a way that the direction in which the thermal shrinkage rate of the cover member is minimized and the direction in which the thermal shrinkage rate of the circularly polarizing plate is minimized are the same as the bending direction of the display panel. Figure 8The result of winding the panel unit in such a way that the direction in which the heat shrinkage rate of the cover member is minimized coincides with the bending direction of the display panel and the direction in which the heat shrinkage rate of the circular polarizing plate is minimized is orthogonal to the bending direction of the display panel. From this result, it can be seen that the influence of the direction of the magnitude of the heat shrinkage rate of the circular polarizing plate is small, and the direction in which the heat shrinkage rate of the cover member is minimized is important.

[0106] Figure 8 of (f) and Figure 8 of (h) shows the panel unit in the state of being unwound after being placed in an environment of 95°C for 18 hours in a state where the panel unit obtained by laminating the display panel, the circular polarizing plate, the optical adhesive sheet, and the cover member in this order is wound into a ring shape with a radius of approximately 20 mm. Figure 8 The result of winding the panel unit in such a way that the direction in which the heat shrinkage rate of the cover member is minimized is orthogonal to the bending direction of the display panel, but the direction in which the heat shrinkage rate of the circular polarizing plate is minimized coincides with the bending direction of the display panel. Figure 8 The result of winding the panel unit in such a way that the direction in which the heat shrinkage rate of the cover member is minimized and the direction in which the heat shrinkage rate of the circular polarizing plate is minimized are orthogonal to the bending direction of the display panel. From this result, it can be seen that the influence of the direction of the magnitude of the heat shrinkage rate of the circular polarizing plate is small, and the direction in which the heat shrinkage rate of the cover member is minimized is important.

[0107] As described above, the experimental results regarding the curl of the display panel and the like have been described.

[0108] (Other embodiments, etc.)

[0109] As described above, the display device of the present invention has been described according to the embodiments, but the present invention is not limited to the above embodiments. Modification examples obtained by making various modifications that can be conceived by those skilled in the art to the above embodiments without departing from the gist of the present invention, and various devices incorporating the display panel of the present invention are also included in the present invention.

[0110] Industrial Applicability

[0111] The display device of the present invention can be used for digital TVs, digital signage, smartphones, tablet terminals, or wearable terminals, etc.

Claims

1. A display device, characterized in that, the display device includes: a display panel that can be wound or bent; and a cover member laminated on the display panel and capable of being wound or bent together with the display panel, the display device satisfies the following (1) or (2): (1) When the display panel is wound, the thermal shrinkage rate of the cover member in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the cover member in the orthogonal direction orthogonal to the bending direction, (2) When the display panel is bent, the thermal shrinkage rate of the cover member in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the cover member in the orthogonal direction orthogonal to the bending direction.

2. The display device according to claim 1, characterized in that, the cover member is laminated on the display panel in such a manner that the direction in which the thermal shrinkage rate of the cover member is the smallest coincides with the bending direction.

3. The display device according to claim 1 or 2, characterized in that, the display device further includes a circularly polarized light plate, the circularly polarized light plate is laminated between the display panel and the cover member and can be wound or bent together with the display panel, the thermal shrinkage rate of the circularly polarized light plate in the bending direction is smaller than the thermal shrinkage rate of the circularly polarized light plate in the orthogonal direction orthogonal to the bending direction.

4. The display device according to claim 3, characterized in that, the circularly polarized light plate is laminated between the display panel and the cover member in such a manner that the direction in which the thermal shrinkage rate of the circularly polarized light plate is the smallest coincides with the bending direction.

5. The display device according to claim 3, characterized in that, the cover member and the circularly polarized light plate are integrally formed with each other.

6. A display device, characterized in that, the display device includes: a display panel that can be wound or bent; a cover member laminated on the display panel and capable of being wound or bent together with the display panel; and a circularly polarized light plate laminated between the display panel and the cover member and capable of being wound or bent together with the display panel, the cover member does not thermally shrink, the display device satisfies the following (1) or (2): (1) When the display panel is wound, the thermal shrinkage rate of the circularly polarized light plate in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the circularly polarized light plate in the orthogonal direction orthogonal to the bending direction, (2) When the display panel is bent, the thermal shrinkage rate of the circularly polarized light plate in the bending direction in which the display panel bends is smaller than the thermal shrinkage rate of the circularly polarized light plate in the orthogonal direction orthogonal to the bending direction.

Images