Display device

Abstract

To provide a display device that can improve the display quality.SOLUTION: A display device includes a display panel, a transparent substrate ME1, a fixing member, and a first light source unit. The transparent substrate ME1 includes a first main surface (Sa1), a first light incidence surface corresponding to a side surface (Sb1) in contact with the first main surface at a first side (SI5), and a first non-light incidence surface corresponding to another side surface in contact with the first main surface at a second side. The shape of the first light incidence surface and the shape of the first non-light incidence surface are different.SELECTED DRAWING: Figure 15

Description

[Technical field]

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

[0002] In recent years, display devices have been proposed that include a polymer dispersed liquid crystal (hereinafter sometimes referred to as "PDLC") panel that can switch between a diffusion state that diffuses incident light and a transmission state that transmits the incident light, and that can display an image while allowing the background to be seen through. In such display devices, one frame period has multiple subframe periods, and a multi-color display is achieved by displaying an image while switching the display color for each subframe period. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-174531 A [Patent Document 2] JP 2022-174556 A [Patent Document 3] International Publication No. 2022 / 158478 Summary of the Invention [Problem to be solved by the invention]

[0004] The present embodiment provides a display device capable of improving the display quality. [Means for solving the problem]

[0005] A display device according to an embodiment includes: a display panel having a display area for displaying an image and transmitting external light; a transparent substrate having a first main surface overlapping the display region, a first light-entering surface which is a side surface contacting the first main surface at a first side, and a first non-light-entering surface which is another side surface contacting the first main surface at a second side; a fixing member positioned between the transparent substrate and the display panel, the fixing member fixing the display panel to the transparent substrate; a first light source unit that faces the first light incident surface of the transparent substrate and irradiates the first light incident surface with light, The first light-entering surface and the first non-light-entering surface have different shapes.

[0006] Moreover, the display device according to one embodiment includes: a display panel having a display area for displaying an image and transmitting external light; a transparent substrate having a first main surface overlapping the display region, a first light-entering surface which is a side surface contacting the first main surface at a first side, and a first non-light-entering surface which is another side surface contacting the first main surface at a second side; a fixing member positioned between the transparent substrate and the display panel, the fixing member fixing the display panel to the transparent substrate; a first light source unit that faces the first light incident surface of the transparent substrate and irradiates the first light incident surface with light, the transparent substrate further has a first corner portion located on the first side and a second corner portion located on the second side, The second corner is chamfered, The first corner is sharper than the second corner. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a plan view showing an example of the configuration of a display device according to a first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing the display device of FIG. 1 in an exploded state. [Diagram 3] FIG. 3 is a diagram showing the main components of the display device of FIG. [Figure 4A] FIG. 4A is a diagram showing a part of a display panel of the display device, and is a diagram showing a schematic view of a liquid crystal layer in a transparent state. [Figure 4B] FIG. 4B is a diagram showing a part of the display panel, and is a diagram showing a schematic diagram of a liquid crystal layer in a scattering state. [Figure 5A] FIG. 5A is a developed cross-sectional view of a display panel and a transparent substrate when the liquid crystal layer is in a transparent state, and also shows light-emitting elements. [Figure 5B] FIG. 5B is a developed cross-sectional view of the display panel and the transparent substrate when the liquid crystal layer is in a scattering state, and also shows light-emitting elements. [Figure 6] FIG. 6 is a graph showing the scattering characteristics of a liquid crystal layer. [Figure 7A] FIG. 7A is a diagram showing an overview of one-line inversion driving. [Figure 7B] FIG. 7B is a diagram showing an overview of two-line inversion driving. [Figure 7C] FIG. 7C is a diagram illustrating an overview of frame inversion driving. [Figure 8] FIG. 8 is a diagram showing an example of a common voltage and a source line voltage in display driving. [Figure 9] FIG. 9 is a diagram showing an example of a common voltage and a source line voltage in transparent driving. [Figure 10] FIG. 10 is a diagram showing another example of the common voltage and the source line voltage in the transparent driving mode. [Figure 11] FIG. 11 is a diagram illustrating an example of a configuration of the timing controller illustrated in FIG. [Figure 12] FIG. 12 is an exploded perspective view showing the display panel and cover panel of the display device, illustrating the state before the display panel is adhered to the cover panel. [Figure 13] FIG. 13 is a cross-sectional view showing the display device. [Figure 14] FIG. 14 is a perspective view showing an exploded view of the transparent substrate according to the first embodiment. [Figure 15] FIG. 15 is a cross-sectional view showing the transparent substrate of FIG. 14 taken along line XV-XV. [Figure 16] FIG. 16 is a cross-sectional view showing the transparent substrate of FIG. 14 taken along line XVI-XVI. [Figure 17] FIG. 17 is a cross-sectional view showing the transparent substrate of FIG. 14 taken along line XVII-XVII. [Figure 18] FIG. 18 is a cross-sectional view showing the transparent substrate of FIG. 14 taken along line XVIII-XVIII. [Figure 19] 19 is an enlarged perspective view of a portion of the transparent substrate of FIG. [Figure 20] FIG. 20 is a cross-sectional view showing a transparent substrate according to a modified example of the first embodiment. [Figure 21] FIG. 21 is a cross-sectional view showing a display device according to the second embodiment. [Figure 22] FIG. 22 is a plan view showing a cover panel, a first light source unit, and a second light source unit according to the second embodiment. [Diagram 23] FIG. 23 is a cross-sectional view showing the transparent substrate according to the second embodiment. [Figure 24] FIG. 24 is a cross-sectional view showing a transparent substrate according to Modification 1 of the second embodiment. [Diagram 25] FIG. 25 is a cross-sectional view showing a transparent substrate according to Modification 2 of the second embodiment. [Figure 26] FIG. 26 is a cross-sectional view showing a display device according to the third embodiment. [Figure 27] FIG. 27 is a plan view showing the cover panel, the first light source unit, and the optical members of the display device according to the third embodiment. [Figure 28] FIG. 28 is a perspective view showing a part of the optical member according to the third embodiment. 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 conceive of appropriate modifications while maintaining the gist of the invention 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] In each embodiment, a display device to which a polymer dispersed liquid crystal is applied will be described as an example of the display device.

[0010] (First embodiment) FIG. 1 is a plan view showing an example of the configuration of a display device DSP in this embodiment. As shown in FIG. 1, the first direction X and the second direction Y intersect with each other, and the third direction Z intersects with the first direction X and the second direction Y. The first direction X corresponds to the row direction, and the second direction Y corresponds to the column direction. In one example, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but may intersect with each other at an angle other than 90 degrees. In this specification, the direction toward the tip of the arrow indicating the third direction Z is referred to as upward (or simply upward), and the direction in the opposite direction from the tip of the arrow is referred to as downward (or simply downward).

[0011] The display device DSP includes a display panel PNL and wiring boards F1, F2, F4, and F5. The display panel PNL includes a display area DA for displaying an image, and a frame-shaped non-display area NDA surrounding the display area DA. The display area DA includes n gate lines G (G1 to Gn), m source lines S (S1 to Sm), and the like. Note that both n and m are positive integers, and n may be equal to m or may be different from m. The gate lines G each extend in a first direction X and are arranged at intervals in a second direction Y. In other words, the gate lines G extend in the row direction. The source lines S each extend in the second direction Y and are arranged at intervals in the first direction X. The display panel PNL has ends E1 and E2 along the first direction X and ends E3 and E4 along the second direction Y.

[0012] The wiring board F1 includes a gate driver GD. A plurality of gate lines G are connected to the gate driver GD. The wiring board F2 includes a source driver SD. A plurality of source lines S are connected to the source driver SD. The wiring boards F1 and F2 are connected to the display panel PNL and the wiring board F4, respectively. The wiring board F5 includes a timing controller TC, a power supply circuit PC, and the like. The wiring board F4 is connected to the connector CT of the wiring board F5. The wiring boards F1 and F2 may be replaced with a single wiring board. Alternatively, the wiring boards F1, F2, and F4 may be replaced with a single wiring board. The gate driver GD, the source driver SD, and the timing controller TC described above constitute the control unit CON of this embodiment, and the control unit CON is configured to control the driving of the plurality of gate lines G, the plurality of source lines S, the plurality of pixel electrodes described later, the common electrode described later, and the light source unit described later.

[0013] Fig. 2 is a cross-sectional view showing an expanded view of the display device DSP in Fig. 1. Here, only a part of the configuration will be described in a cross section of the display device DSP in a YZ plane defined by the second direction Y and the third direction Z.

[0014] As shown in Fig. 2, the display device DSP includes a cover panel CO1. The cover panel CO1 includes a transparent substrate ME1. The transparent substrate ME1 is a cover glass and is made of glass. The transparent substrate ME1 is a non-flexible substrate. The transparent substrate ME1 overlaps at least the entire display area DA.

[0015] The transparent substrate ME1 has a principal surface Sa1, a principal surface Sa2, a side surface Sb1, and a side surface Sb2. The principal surface Sa2 is located on the opposite side to the principal surface Sa1. The principal surfaces Sa1 and Sa2 overlap with the display area DA.

[0016] The side surface Sb1 is located between the main surface Sa1 and the main surface Sa2. The side surface Sb1 is a first light entrance surface. The side surface Sb2 is located between the main surface Sa1 and the main surface Sa2, and is located on the opposite side to the side surface Sb1. In this embodiment, the side surface Sb1 and the side surface Sb2 are located in the non-display area NDA. The angle between the main surface Sa1 and the side surface Sb1 is defined as θ1. In this embodiment, the angle θ1 is 90°.

[0017] The display panel PNL has a display area DA that displays an image and transmits external light. The display panel PNL faces the main surface Sa1 of the transparent substrate ME1. The display panel PNL is flexible. The display panel PNL includes a first substrate SUB1, a second substrate SUB2, and a liquid crystal layer 30 as a display function layer. The first substrate SUB1 includes a transparent first substrate 10, a pixel electrode 11, an alignment film 12, and the like. The second substrate SUB2 includes a transparent second substrate 20, a common electrode 21, an alignment film 22, and the like. The second substrate 20 is located between the first substrate 10 and the transparent substrate ME1. The pixel electrode 11 and the common electrode 21 are formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The liquid crystal layer 30 is located at least in the display area DA.

[0018] The liquid crystal layer 30 is located between the first substrate 10 (first substrate SUB1) and the second substrate 20 (second substrate SUB2). More specifically, the liquid crystal layer 30 is located between the alignment film 12 and the alignment film 22. The liquid crystal layer 30 contains polymer dispersed liquid crystal. The liquid crystal layer 30 of this embodiment uses reverse mode polymer dispersed liquid crystal (R-PDLC). The liquid crystal layer 30 maintains the parallelism of incident light when the applied voltage is low, and scatters the incident light when the applied voltage is high. The first substrate SUB1 and the second substrate SUB2 are bonded by a seal material 40. The first substrate SUB1 has an extension portion EX that extends in the second direction Y beyond the side surface Sc1 of the second substrate 20.

[0019] The adhesive sheet AD1 is located between the transparent substrate ME1 and the display panel PNL, and adheres the display panel PNL to the transparent substrate ME1. The adhesive sheet AD1 is in contact with and adheres to the transparent substrate ME1 on one side, and in contact with and adheres to the display panel PNL on the other side. The adhesive sheet AD1 overlaps at least the entire display area DA. The adhesive sheet AD1 is formed of an optically clear adhesive (OCA) as a solid adhesive. However, the adhesive sheet AD1 may be formed of a material other than OCA, for example, an optically clear resin (OCR). Furthermore, the display panel PNL and the transparent substrate ME1 may be bonded together. That is, the present embodiment includes a structure in which the display panel PNL and the transparent substrate ME1 are fixed together. Therefore, the adhesive sheet AD1 is also called a fixing member. It is also preferable that no air layer is located between the display panel PNL and the transparent substrate ME1.

[0020] The wiring boards F1 and F2 are connected to the extending portion EX of the first substrate SUB1. The first light source unit LU1 is located in the non-display area NDA outside the display area DA. The first light source unit LU1 includes a light-emitting element LS, a wiring board F6, and the like. The light-emitting element LS is connected to the wiring board F6 and is located on the extension portion EX. The light-emitting element LS faces the side surface Sb1 and has a light-emitting portion (light-emitting surface) EM that irradiates light to the side surface Sb1.

[0021] As described below, illumination light emitted from the light-emitting unit EM is incident on the side surface Sb1 and propagates through the transparent substrate ME1 (cover panel CO1), the adhesive sheet AD1, and the display panel PNL. In this embodiment, the light-emitting unit EM also faces the side surface Sc1 of the second base material 20. Illumination light emitted from the light-emitting unit EM is also incident on the side surface Sc1.

[0022] The first base material 10 and the second base material 20 are each formed of glass. The first base material 10 has a thickness Tb1, and the second base material 20 has a thickness Tb2. The thicknesses Tb1 and Tb2 are each 0.2 mm or less. More specifically, the thicknesses Tb1 and Tb2 are each 0.1 to 0.2 mm. In this embodiment, the thicknesses Tb1 and Tb2 are each 0.15 mm. By forming the first base material 10 and the second base material 20 thin, it is possible to provide flexibility to the display panel PNL.

[0023] Here, in the direction in which the transparent substrate ME1 and the display panel PNL face each other, the transparent substrate ME1 has a thickness Ta, and the display panel PNL has a thickness Tb. The thickness Tb includes thickness Tb1, thickness Tb2, the thickness of the liquid crystal layer 30, and the like. It is desirable that the thickness Ta of the transparent substrate ME1 be larger than the thickness Tb of the display panel PNL. In this embodiment, the thickness Ta of the transparent substrate ME1 is larger than the thickness Tb of the display panel PNL. The thickness Ta is 0.7 to 3.0 mm.

[0024] As described above, even if the thickness Tb2 of the second base material 20 is reduced, the transparent substrate ME1 has a thickness Ta that is greater than the thickness Tb2. The first light source unit LU1 can irradiate light onto the side surface Sb1 of the transparent substrate ME1. Therefore, compared to the case where the first light source unit LU1 irradiates light onto the side surface Sc1 of the second base material 20, the user can better view the display image of the display device DSP. For example, the contrast ratio of the display device DSP can be increased.

[0025] In this embodiment, the first light source unit LU1 irradiates light not only to the side surface Sb1 but also to the side surface Sc1, allowing the user to more clearly view the image displayed on the display device DSP.

[0026] In this embodiment, the transparent substrate ME1 and the display panel PNL are curved. However, the transparent substrate ME1 and the display panel PNL do not have to be curved. In that case, as shown in FIG. 2, the main surface Sa1 and the like only need to be parallel to the XY plane.

[0027] FIG. 3 is a diagram showing the main components of the display device DSP shown in FIG. 3, the display device DSP includes a controller CNT indicated by a dashed line in the figure. The controller CNT includes a timing controller TC, a gate driver GD, a source driver SD, a Vcom circuit VC, a light source driver LSD, and the like.

[0028] The timing controller TC generates various signals based on image data and synchronization signals input from the outside. In one example, the timing controller TC performs predetermined signal processing based on the image data and outputs a video signal generated to the source driver SD. The timing controller TC also outputs control signals generated based on the synchronization signal to the gate driver GD, the source driver SD, the Vcom circuit VC, and the light source driver LSD. The timing controller TC will be described in detail later.

[0029] A plurality of pixels PX are arranged in a display area DA indicated by a two-dot chain line in the figure. Each pixel PX includes a switching element SW and a pixel electrode 11. The switching element SW is formed of, for example, a thin film transistor. The switching element SW is electrically connected to a gate line G and a source line S. A plurality of pixel electrodes 11 are located in the display area DA and are arranged in a matrix. Therefore, for example, a plurality of pixel electrodes 11 are arranged in a plurality of rows. The pixel electrodes 11 are connected to the source line S via the switching element SW. A common electrode 21 is located in the display area DA. The common electrode 21 faces the plurality of pixel electrodes 11. Unlike this embodiment, the common electrode 21 may be divided into at least one pixel PX, each of which is connected to a common line and a common common voltage is applied to the common electrodes 21.

[0030] A gate signal is supplied to each of the gate lines G from the gate driver GD. A video signal (image signal) is supplied to each of the source lines S from the source driver SD. A common voltage Vcom is supplied to the common electrode 21 from the Vcom circuit VC. The video signal supplied to the source line S is applied to the pixel electrode 11 connected to the switching element SW during a period in which the switching element SW is in a conductive state based on the gate signal supplied to the gate line G. In the following description, applying a video signal to the pixel electrode 11 to form a potential difference between the pixel electrode 11 and the common electrode 21 may be described as writing a video signal to the pixel PX including the pixel electrode 11 (or applying a voltage).

[0031] The first light source unit LU1 is configured to irradiate the liquid crystal layer 30 with light. In this embodiment, the first light source unit LU1 is configured to irradiate the liquid crystal layer 30 with light of a color other than achromatic colors. The first light source unit LU1 includes light-emitting elements LS of multiple colors. For example, the first light source unit LU1 includes a light-emitting element (first light-emitting element) LSR that irradiates the liquid crystal layer 30 with light of a first color, a light-emitting element (second light-emitting element) LSG that irradiates the liquid crystal layer 30 with light of a second color, and a light-emitting element (third light-emitting element) LSB that irradiates the liquid crystal layer 30 with light of a third color. It goes without saying that the first color, the second color, and the third color are different from each other. In this embodiment, the first color is red, the second color is green, and the third color is blue.

[0032] The light source driver LSD controls the lighting periods of these light emitting elements LSR, LSG, and LSB. As will be described in detail later, in a driving method in which one frame period has multiple subframe periods, at least one of the three light emitting elements LSR, LSG, and LSB lights up in each subframe, and the color of the illumination light is switched for each subframe.

[0033] An example of the configuration of a display device including a liquid crystal layer 30 that is a polymer dispersed liquid crystal layer will be described below. FIG. 4A is a diagram showing a part of the display panel PNL, and is a diagram showing a schematic view of the liquid crystal layer 30 in a transparent state.

[0034] As shown in FIG. 4A, the liquid crystal layer 30 includes a liquid crystal polymer 31, which is a streaky polymer, and liquid crystal molecules 32. The liquid crystal polymer 31 is obtained, for example, by polymerizing a liquid crystal monomer in a state where the liquid crystal monomer is aligned in a predetermined direction by the alignment restraining force of the alignment films 12 and 22. The liquid crystal molecules 32 are dispersed in the liquid crystal monomer, and are aligned in a predetermined direction depending on the alignment direction of the liquid crystal monomer when the liquid crystal monomer is polymerized. In this embodiment, the alignment films 12 and 22 are horizontal alignment films that initially align the liquid crystal monomer and the liquid crystal molecules 32 along the XY plane defined by the first direction X and the second direction Y. The liquid crystal molecules 32 are positive-type liquid crystal molecules having a positive dielectric anisotropy. However, unlike this embodiment, the alignment films 12 and 22 may be vertical alignment films that initially align the liquid crystal monomer and the liquid crystal molecules 32 along the third direction Z. In addition, the liquid crystal molecules 32 may be negative type liquid crystal molecules having negative dielectric anisotropy.

[0035] The liquid crystal polymer 31 and the liquid crystal molecules 32 have the same optical anisotropy. Alternatively, the liquid crystal polymer 31 and the liquid crystal molecules 32 have approximately the same refractive index anisotropy. That is, the liquid crystal polymer 31 and the liquid crystal molecules 32 have approximately the same ordinary refractive index and extraordinary refractive index. The ordinary refractive index and extraordinary refractive index of the liquid crystal polymer 31 and the liquid crystal molecules 32 do not have to be completely the same, and deviations due to manufacturing errors and the like are allowed. In addition, the responsiveness of the liquid crystal polymer 31 and the liquid crystal molecules 32 to an electric field is different. That is, the responsiveness of the liquid crystal polymer 31 to an electric field is lower than that of the liquid crystal molecules 32 to an electric field.

[0036] The example shown in Figure 4A corresponds to, for example, a state in which no voltage is applied to the liquid crystal layer 30 (a state in which the potential difference between the pixel electrode 11 and the common electrode 21 is zero), or a state in which a second transparent voltage described later is applied to the liquid crystal layer 30.

[0037] 4A, the optical axis Ax1 of the liquid crystal polymer 31 and the optical axis Ax2 of the liquid crystal molecule 32 are parallel to each other. In the illustrated example, both the optical axis Ax1 and the optical axis Ax2 are parallel to the first direction X. The optical axis here corresponds to a line parallel to the traveling direction of a light ray whose refractive index has one value regardless of the polarization direction.

[0038] As described above, the liquid crystal polymer 31 and the liquid crystal molecules 32 have substantially the same refractive index anisotropy, and the optical axes Ax1 and Ax2 are parallel to each other, so that there is almost no difference in refractive index between the liquid crystal polymer 31 and the liquid crystal molecules 32 in all directions including the first direction X, the second direction Y, and the third direction Z. Therefore, the light L1 incident on the liquid crystal layer 30 in the third direction Z is transmitted through the liquid crystal layer 30 without being substantially scattered. The liquid crystal layer 30 can maintain the parallelism of the light L1. Similarly, the light L2 and L3 incident in an oblique direction inclined to the third direction Z are hardly scattered in the liquid crystal layer 30. Therefore, high transparency is obtained. The state shown in FIG. 4A is called a "transparent state".

[0039] FIG. 4B is a diagram showing a part of the display panel PNL, and is a diagram showing a schematic view of the liquid crystal layer 30 in a scattering state. As shown in FIG. 4B, as described above, the responsiveness of the liquid crystal polymer 31 to the electric field is lower than that of the liquid crystal molecules 32 to the electric field. Therefore, in a state where a voltage (scattering voltage described later) higher than each of the second transparent voltage and the first transparent voltage described later is applied to the liquid crystal layer 30, the alignment direction of the liquid crystal polymer 31 hardly changes, whereas the alignment direction of the liquid crystal molecules 32 changes according to the electric field. That is, as shown in the figure, the optical axis Ax1 is almost parallel to the first direction X, whereas the optical axis Ax2 is inclined with respect to the first direction X. Therefore, the optical axes Ax1 and Ax2 intersect with each other. Therefore, a large refractive index difference occurs between the liquid crystal polymer 31 and the liquid crystal molecules 32 in all directions including the first direction X, the second direction Y, and the third direction Z. As a result, the light L1 to L3 incident on the liquid crystal layer 30 is scattered within the liquid crystal layer 30. The state shown in FIG. 4B is called a "scattering state". The control unit CON switches the liquid crystal layer 30 to at least one of a transparent state and a scattering state.

[0040] 5A is a cross-sectional view showing the display panel PNL and the transparent substrate ME1 in an expanded state when the liquid crystal layer 30 is in a transparent state, and also showing the light-emitting element LS. As shown in FIG. 5A, the first substrate 10 has a lower surface 10B, and the second substrate 20 has an upper surface 20T. Illumination light emitted from the light-emitting element LS is incident on the cover panel CO1 and the display panel PNL from the side surface Sb1 of the transparent substrate ME1 and the side surface Sc1 of the second substrate 20.

[0041] For example, illumination light L11 emitted from the light-emitting element LS and incident on the side surface Sb1 of the transparent substrate ME1 propagates through the transparent substrate ME1, the adhesive sheet AD1, the second base material 20, the liquid crystal layer 30, the first base material 10, etc. When the liquid crystal layer 30 is in a transparent state, the illumination light L11 is hardly scattered by the liquid crystal layer 30, and therefore hardly leaks out from the lower surface 10B of the first base material 10 and the main surface Sa2 of the transparent substrate ME1 to the outside.

[0042] External light L12 incident on the display panel PNL is transmitted through the liquid crystal layer 30 with almost no scattering. That is, external light incident on the display panel PNL from the lower surface 10B is transmitted through the main surface Sa2 of the transparent substrate ME1, and external light incident from the main surface Sa2 is transmitted through the lower surface 10B. Therefore, when the display device DSP is observed from the main surface Sa2 side, the user can see the background on the lower surface 10B side through the display panel PNL. Similarly, when the display device DSP is observed from the lower surface 10B side, the user can see the background on the main surface Sa2 side through the display panel PNL.

[0043] 5B is a cross-sectional view showing the display panel PNL and the transparent substrate ME1 in an expanded state when the liquid crystal layer 30 is in a scattering state, and also showing the light-emitting element LS. As shown in FIG. 5B, illumination light emitted from the light-emitting element LS is incident on the cover panel CO1 and the display panel PNL from the side surface Sb1 of the transparent substrate ME1 and the side surface Sc1 of the second base material 20.

[0044] For example, illumination light L21 emitted from the light-emitting element LS and incident on the side surface Sb1 of the transparent substrate ME1 propagates through the transparent substrate ME1, the adhesive sheet AD1, the second base material 20, the liquid crystal layer 30, the first base material 10, etc. In the illustrated example, the liquid crystal layer 30 between the pixel electrode 11α and the common electrode 21 (the liquid crystal layer to which the voltage applied between the pixel electrode 11α and the common electrode 21 is applied) is in a transparent state, so that the illumination light L21 is hardly scattered in the region of the liquid crystal layer 30 facing the pixel electrode 11α.

[0045] On the other hand, since the liquid crystal layer 30 between the pixel electrode 11β and the common electrode 21 (the liquid crystal layer to which the voltage is applied between the pixel electrode 11β and the common electrode 21) is in a scattering state, the illumination light L21 is scattered in a region facing the pixel electrode 11β of the liquid crystal layer 30. Of the illumination light L21, a part of the scattered light L211 is emitted to the outside from the principal surface Sa2, and a part of the scattered light L212 is emitted to the outside from the lower surface 10B.

[0046] At the position overlapping with the pixel electrode 11α, the external light L22 incident on the display panel PNL is transmitted through without being scattered by the liquid crystal layer 30, similar to the external light L12 shown in Fig. 5A. At the position overlapping with the pixel electrode 11β, the external light L23 incident from the lower surface 10B is partially transmitted through the principal surface Sa2 after being scattered by the liquid crystal layer 30, at a portion L231. Moreover, the external light L24 incident from the principal surface Sa2 is partially transmitted through the lower surface 10B after being scattered by the liquid crystal layer 30, at a portion L241.

[0047] Therefore, when observing the display device DSP from the main surface Sa2 side, the color of the illumination light L21 can be visually recognized at the position overlapping with the pixel electrode 11β. In addition, since a part of the external light L231 passes through the display panel PNL, the background on the lower surface 10B side can also be visually recognized through the display panel PNL. Similarly, when observing the display device DSP from the lower surface 10B side, the color of the illumination light L21 can be visually recognized at the position overlapping with the pixel electrode 11β. In addition, since a part of the external light L241 passes through the display panel PNL, the background on the main surface Sa2 side can also be visually recognized through the display panel PNL. Note that at the position overlapping with the pixel electrode 11α, since the liquid crystal layer 30 is in a transparent state, the color of the illumination light L21 is hardly visually recognized, and the background can be visually recognized through the display panel PNL.

[0048] FIG. 6 is a graph showing the scattering characteristics of the liquid crystal layer 30, and represents the relationship between the voltage VLC applied to the liquid crystal layer 30 and the luminance. The luminance here corresponds to the luminance of the scattered light L211 obtained when the illumination light L21 emitted from the light-emitting element LS is scattered by the liquid crystal layer 30, as shown in FIG. 5B for example. From another point of view, this luminance represents the degree of scattering of the liquid crystal layer 30.

[0049] As shown in FIG. 6, when the voltage VLC is increased from 0 V, the luminance sharply increases from about 8 V and saturates at about 20 V. Note that even when the voltage VLC is between 0 V and 8 V, the luminance slightly increases. In the present embodiment, the voltage in the region surrounded by the two-dot chain line, that is, the range of 8 V to 16 V, is used for the gradation expression (for example, 256 gradations) of each pixel PX. Hereinafter, the voltage of 8 V < VLC ≤ 16 V is referred to as the “scattering voltage”. In the present embodiment, the voltage in the region surrounded by the one-dot chain line, that is, 0 V ≤ VLC ≤ 8 V, is referred to as the “transparent voltage”. The transparent voltage VA includes the first transparent voltage VA1 and the second transparent voltage VA2 described above. Note that the lower limit value and the upper limit value of the scattering voltage VB and the transparent voltage VA are not limited to this example, and can be appropriately determined according to the scattering characteristics of the liquid crystal layer 30.

[0050] Here, the degree of scattering when the degree of scattering of light incident on the liquid crystal layer 30 is highest when a scattering voltage VB is applied to the liquid crystal layer 30 is set to 100%. Here, the degree of scattering when a scattering voltage VB of 16V is applied to the liquid crystal layer 30 is set to 100%. For example, the transparent voltage VA can be defined as the range of voltage VLC where the degree of scattering (brightness) is less than 10%. Alternatively, the transparent voltage VA can be defined as a voltage VLC equal to or lower than the voltage corresponding to the lowest grayscale (8V in the example of FIG. 6). Furthermore, the transparent voltage VA (the first transparent voltage VA1 and the second transparent voltage VA2) may be different from the example shown in Fig. 6. For example, the first transparent voltage VA1 may be a voltage that results in a scattering degree in the range of 10% to 50%. Furthermore, the second transparent voltage VA2 may be a voltage that results in a scattering degree in the range of less than 10%.

[0051] 6 is applicable to cases where the polarity of the voltage applied to the liquid crystal layer 30 is positive (+) or negative (-). In the latter case, the voltage VLC is the absolute value of the negative voltage.

[0052] The display device DSP can employ polarity inversion driving that inverts the polarity of the voltage applied to the liquid crystal layer 30. Figures 7A, 7B, and 7C are diagrams showing an overview of polarity inversion driving. 7A shows one-line inversion driving in which the voltage applied to the liquid crystal layer 30 (voltage written to the pixels PX) is inverted between positive polarity (+) and negative polarity (-) for each group of pixels PX (one line) connected to one gate line G. In such a driving method, for example, the polarity of the common voltage supplied to the common electrode 21 and the polarity of the video signal supplied from the source driver SD to the source line S (polarity of the source line voltage) are inverted for each horizontal period in which the gate driver GD supplies a gate signal to the gate line G. In the same horizontal period, the polarity of the common voltage and the polarity of the video signal are, for example, opposite to each other.

[0053] 7B shows two-line inversion driving in which the voltage applied to the liquid crystal layer 30 is inverted between positive polarity (+) and negative polarity (-) every two lines. The example is not limited to that shown in FIG. 7A and FIG. 7B, and the polarity may be inverted every three or more lines.

[0054] 7C shows frame inversion driving in which the voltage applied to the liquid crystal layer 30 is inverted between positive (+) and negative (-) polarities for each frame period in which an image corresponding to one piece of image data is displayed. In such a driving method, for example, the polarity of the common voltage and the polarity of the video signal are inverted for each frame period. In the same frame period, the polarity of the common voltage and the polarity of the video signal are, for example, opposite to each other.

[0055] FIG. 8 is a diagram showing an example of a common voltage Vcom supplied to the common electrode 21 and a source line voltage Vsig supplied to the source line S (or pixel electrode 11) in a display drive that applies the one-line inversion drive shown in FIG. 7A.

[0056] As shown in FIG. 8, for the source line voltage Vsig, a waveform corresponding to the maximum value (max) of the gradation and a waveform corresponding to the minimum value (min) of the gradation are shown. Here, the waveform of the source line voltage Vsig(min) is shown by a solid line, the waveform of the common voltage Vcom is shown by a two-dot chain line, and the waveform of the source line voltage Vsig(max) is shown by a dashed line. In the example of this figure, the common voltage Vcom and the source line voltage Vsig (see the maximum value waveform) are inverted in polarity every frame period Pf. The reference voltage Vsig-c is, for example, 8V. For each of the common voltage Vcom and the source line voltage Vsig, the lower limit is 0V and the upper limit is 16V. However, when the frame period Pf includes multiple subframe periods, the polarity of the common voltage Vcom and the polarity of the source line voltage Vsig may be inverted every frame period Pf, or may be inverted every field period.

[0057] 8, and focusing on polarity inversion driving including the example of FIG. 9 described later, when the driving voltage (voltage written to pixel PX) applied to the liquid crystal layer 30 is positive, the difference (Vsig-Vcom) between the source line voltage Vsig and the common voltage Vcom is 0V or a positive voltage value. On the other hand, when the driving voltage (voltage written to pixel PX) applied to the liquid crystal layer 30 is negative, the difference (Vsig-Vcom) between the source line voltage Vsig and the common voltage Vcom is 0V or a negative voltage value.

[0058] 8, in a period in which a positive voltage is written to the pixel PX, the common voltage Vcom is 0V, and the source line voltage Vsig has a voltage value in the range of 8V or more and 16V or less according to the gradation indicated by the image data. On the other hand, in a period in which a negative voltage is written to the pixel PX, the common voltage Vcom is 16V, and the source line voltage Vsig has a voltage value in the range of 0V or more and 8V or less according to the gradation indicated by the image data. That is, in either case, a voltage in the range of 8V or more and 16V or less is applied between the common electrode 21 and the pixel electrode 11.

[0059] 6, even if the voltage VLC applied to the liquid crystal layer 30 is 8 V, in other words, even if the first transparent voltage VA1 is applied to the liquid crystal layer 30, the liquid crystal layer 30 has a scattering degree of about 0 to 10%. Therefore, even if the source line voltage Vsig is set to the minimum grayscale value, the external light incident on the display panel PNL is slightly scattered, which may reduce the visibility of the background of the display panel PNL. Therefore, by incorporating transparent driving, which makes the voltage between the pixel electrode 11 and the common electrode 21 smaller than the lower limit of the gradation, into the image display sequence, the visibility of the background of the display panel PNL can be improved.

[0060] Here, the relationship between the output of the source driver SD and the common voltage Vcom will be described. When the withstand voltage of the source driver SD is low, the common voltage Vcom is inverted to increase the liquid crystal application voltage. At this time, the source driver SD can only output either a positive source line voltage Vsig (e.g., reference voltage Vsig-c to 16V) or a negative source line voltage Vsig (e.g., 0V to reference voltage Vsig-c) at the same time. The polarity of the common voltage Vcom is opposite to that of the output of the source driver SD.

[0061] However, when a high-voltage source driver SD is used, the relationship between the source line voltage Vsig and the common voltage Vcom may be as described above, or may be as follows: The common voltage Vcom is fixed at 0V, and the source line voltage Vsig output by the source driver SD is 0 to +16V when positive and -16 to 0V when negative.

[0062] 9 is a diagram showing an example of the common voltage Vcom and the source line voltage Vsig in transparent driving, in which the waveform of the source line voltage Vsig is shown by a solid line, and the waveform of the common voltage Vcom is shown by a two-dot chain line. As shown in FIG. 9, like the example in FIG. 8, the common voltage Vcom alternates between 0V and 16V for each frame period Pf. In transparent driving, the voltage value of the source line voltage Vsig coincides with the common voltage Vcom for each frame period Pf (Vsig=Vcom=0V or Vsig=Vcom=16V). In FIG. 9, the source line voltage Vsig and the common voltage Vcom are shown slightly offset from each other for the sake of illustration. Therefore, 0V is applied to the liquid crystal layer 30. In other words, a second transparent voltage VA2 is applied to the liquid crystal layer 30.

[0063] However, the source line voltage Vsig in transparent driving is not limited to the example shown in FIG. 9. For example, during the period when the common voltage Vcom is 0 V, the source line voltage Vsig may exceed 0 V and be less than 8 V (0 V < Vsig < 8 V). During the period when the common voltage Vcom is 16 V, the source line voltage Vsig may exceed 8 V and be less than 16 V (8 V < Vsig < 16 V). In any case, according to transparent driving, the absolute value of the difference between the source line voltage Vsig and the common voltage Vcom is less than 8 V, and the parallelism of the light transmitted through the liquid crystal layer 30 increases. In other words, the second transparent voltage VA2 is not limited to 0 V, and the absolute value of the second transparent voltage VA2 may be less than 8 V.

[0064] Note that in transparent driving, it is sufficient that the voltage applied to the liquid crystal layer 30 is less than the lower limit value of the gradation (for example, 8 V), and the source line voltage Vsig does not have to exactly match the common voltage Vcom. As described above, when the scattering voltage VB is applied to the liquid crystal layer 30, the degree of scattering when the degree of scattering of the light incident on the liquid crystal layer 30 is the highest is set to 100%. For example, it is desirable that the second transparent voltage VA2 is a voltage at which the degree of scattering is less than 10%.

[0065] FIG. 10 is a diagram showing another example of the common voltage Vcom and the source line voltage Vsig in transparent driving. Here, the waveform of the source line voltage Vsig is shown by a solid line, and the waveform of the common voltage Vcom is shown by a two-dot chain line. As shown in FIG. 10, in this example, in transparent driving, the polarity inversion of the common voltage Vcom and the source line voltage Vsig is stopped. Further, the common voltage Vcom and the source line voltage Vsig coincide at 8 V (the above-mentioned reference voltage Vsig-c). Note that the common voltage Vcom and the source line voltage Vsig may coincide at a voltage other than the reference voltage Vsig-c, such as 0 V. Also, similar to the case shown in FIG. 9, it is desirable that the second transparent voltage VA2 is a voltage at which the degree of scattering is less than 10%. As described above, transparent driving has been described by taking 1-line inversion driving as an example, but the same transparent driving can also be applied to 2-line or more line inversion driving and frame inversion driving.

[0066] Next, a configuration example of the timing controller TC will be described. In this case, a driving method in which one frame period has a plurality of subframe (field) periods is applied to the display device DSP. Such a driving method is called, for example, a field sequential method. In each subframe period, red, green, and blue images are displayed respectively. The images of each color displayed in this time division manner are combined and visually recognized by the user as a multi-color display image.

[0067] FIG. 11 is a diagram showing an example of the configuration of the timing controller TC shown in FIG. As shown in FIG. 11, the timing controller TC includes a timing generation unit 50, a frame memory 51, line memories 52R, 52G, and 52B, a data conversion unit 53, a light source control unit 54, and a detection unit 55 which is an address detection unit.

[0068] Frame memory 51 stores one frame's worth of image data input from the outside. Line memories 52R, 52G, and 52B store red, green, and blue subframe data, respectively. Each subframe data represents a red, green, or blue image (e.g., the gradation value of each pixel PX) to be displayed in a time-division manner in each pixel PX. The subframe data of each color stored in line memories 52R, 52G, and 52B corresponds to the previous frame of image data stored in frame memory 51.

[0069] The data conversion unit 53 performs various data conversion processes such as gamma correction on the subframe data of each color stored in the line memories 52R, 52G, and 52B to generate a video signal, and outputs it to the above-mentioned source driver SD. The timing controller TC may be configured so that the frame memory 51 divides the data into RGB data and sends the RGB data to the data conversion unit 53. In this case, it is also possible to configure the timing controller TC without the line memories 52R, 52G, and 52B.

[0070] The light source control unit 54 outputs a light source control signal to the light source driver LSD described above. The light source driver LSD drives the light emitting elements LSR, LSG, and LSB based on the light source control signal. The light emitting elements LSR, LSG, and LSB can be driven by, for example, PWM (Pulse Width Modulation) control. That is, the light source driver LSD can adjust the luminance of each of the light emitting elements LSR, LSG, and LSB depending on the duty ratio of the signal output to the light emitting elements LSR, LSG, and LSB.

[0071] The timing generation unit 50 controls the operation timings of the frame memory 51, the line memories 52R, 52G, 52B, the data conversion unit 53, and the light source control unit 54 in synchronization with a vertical synchronization signal Vsync and a horizontal synchronization signal Hsync input from the outside. The timing generation unit 50 also controls the source driver SD by outputting a source driver control signal, controls the gate driver GD by outputting a gate driver control signal, and outputs a Vcom control signal.

[0072] The detection unit 55 is configured to detect the address of the image data when the image data of one frame input from the outside includes the image data. The image is a character displayed in a part of the display area DA. The character may be a symbol including a letter, a figure, an icon, or the like. The case where the image data includes character data is a case where at least one of all bits of the digital data includes data other than 0. The address information of the image data is given to the data conversion unit 53. Therefore, when the image data input from the outside includes the image data, the timing controller TC can generate a processed video signal and output it to the source driver SD in order to adjust the degree of scattering (transparency) of the area other than the area where the image is displayed. The processed video signal can be generated by calculation by the data conversion unit 53 or by using data stored in a table 56 of the timing controller TC.

[0073] Next, a process of adhering the display panel PNL to the cover panel CO1 in the manufacturing method of the display device DSP of this embodiment will be described. Fig. 12 is an exploded perspective view showing the display panel PNL and the cover panel CO1 of the display device DSP, showing the state before the display panel PNL is adhered to the cover panel CO1.

[0074] As shown in Fig. 12, a cover panel CO1 is prepared. The transparent substrate ME1 of the cover panel CO1 is formed to be curved. The transparent substrate ME1 is formed to be curved so that the main surface Sa2 side is convex. However, the transparent substrate ME1 may be formed to be curved so that the main surface Sa1 side is convex.

[0075] The transparent substrate ME1 further includes a side surface Sb3 and a side surface Sb4. The side surface Sb1 and the side surface Sb2 each extend in a straight line. More specifically, the side SI1, which is the long side of the side surface Sb1, and the side SI2, which is the long side of the side surface Sb2, are straight lines. On the other hand, the side surfaces Sb3 and Sb4 each extend in a curved manner. More specifically, the side SI3, which is the long side of the side surface Sb3, and the side SI4, which is the long side of the side surface Sb4, are curved lines. From the above, the side surface Sb1 facing the light-emitting element LS is a non-curved surface. The cross section of the transparent substrate ME1 on the YZ plane is not curved, but the cross section of the transparent substrate ME1 on the XZ plane is curved.

[0076] Next, the display panel PNL is adhered to the cover panel CO1. At that time, the adhesive sheet AD1 is adhered to one of the display panel PNL and the cover panel CO1. Here, the adhesive sheet AD1 is adhered to the display panel PNL. Then, the display panel PNL and the cover panel CO1 are arranged facing each other. Before adhering the display panel PNL to the cover panel CO1, the display panel PNL is not curved. Then, the display panel PNL is pressed against the cover panel CO1, and the display panel PNL is adhered to the cover panel CO1. As a result, the display panel PNL is curved in accordance with the cover panel CO1.

[0077] Fig. 13 is a cross-sectional view showing a display device DSP according to this embodiment. In Fig. 13, only the first base material 10 and the second base material 20 of the display panel PNL are shown. As shown in FIG. 13, in a cross section of the display device DSP on a virtual plane parallel to the YZ plane, the cover panel CO1 (transparent substrate ME1), adhesive sheet AD1, and display panel PNL are curved so that the main surface Sa2 side is convex.

[0078] The light-emitting element LS is formed of a light-emitting diode. However, the light-emitting element LS may be a laser or a laser diode. In that case, it is preferable to provide a lens between the light-emitting element LS and the side surfaces Sb1 and Sc1, and to expand the light emitted by the light-emitting element LS in the XY plane direction before it is incident on the side surfaces Sb1 and Sc1.

[0079] The light-emitting element LS can irradiate light onto the side surface Sb1 of the transparent substrate ME1 having a thickness Ta. Since the size of the light-emitting element LS arranged opposite the side surface Sb1 can be increased, the luminance level of the light irradiated by the light-emitting element LS can be increased in proportion to the size. Therefore, the user can clearly view the display image of the display device DSP.

[0080] In this embodiment, the side surface Sb1 and the side surface Sc1 are located on the same plane. Moreover, the light-emitting element LS faces not only the side surface Sb1 of the transparent substrate ME1 but also the side surface Sc1 of the second base material 20. The size of the light-emitting element LS can be further increased, and the luminance level of the light emitted by the light-emitting element LS can be further increased. Therefore, the user can more clearly view the display image of the display device DSP.

[0081] FIG. 14 is a perspective view showing the transparent substrate ME1 according to the first embodiment in an exploded state. As shown in Fig. 14, the transparent substrate ME1 has a rectangular plate shape. The transparent substrate ME1 has sides SI1, SI2, SI3, SI4, SI5, SI6, SI7, SI8, SI9, SI10, SI11, and SI12. The transparent substrate ME1 has vertices V1, V2, V3, V4, V5, V6, V7, and V8. As described above, the transparent substrate ME1 has six faces, twelve sides, and eight vertices.

[0082] The main surface Sa1 and the side surface Sb1 are in contact with each other at a side SI5. The main surface Sa1 and the side surface Sb2 are in contact with each other at a side SI6. The main surface Sa1 and the side surface Sb3 are in contact with each other at a side SI7. The main surface Sa1 and the side surface Sb4 are in contact with each other at a side SI8. The main surface Sa2 and the side surface Sb1 are in contact with each other at a side SI1. The main surface Sa2 and the side surface Sb2 are in contact with each other at a side SI2. The main surface Sa2 and the side surface Sb3 are in contact with each other at a side SI3. The main surface Sa2 and the side surface Sb4 are in contact with each other at a side SI4. The side surface Sb1 and the side surface Sb3 are in contact with each other at a side SI9. The side surface Sb1 and the side surface Sb4 are in contact with each other at a side SI10. The side surface Sb2 and the side surface Sb3 are in contact with each other at a side SI11. The side surface Sb2 and the side surface Sb4 are in contact with each other at a side SI12.

[0083] Vertex V1 is in contact with sides SI1, SI3, and SI9. Vertex V2 is in contact with sides SI5, SI7, and SI9. Vertex V3 is in contact with sides SI1, SI4, and SI10. Vertex V4 is in contact with sides SI5, SI8, and SI10. Vertex V5 is in contact with sides SI2, SI3, and SI11. Vertex V6 is in contact with sides SI6, SI7, and SI11. Vertex V7 is in contact with sides SI2, SI4, and SI12. Vertex V8 is in contact with sides SI6, SI8, and SI12.

[0084] In this embodiment, the multiple faces, multiple sides, and multiple vertices of the transparent substrate ME1 function as follows. Principal surface Sa1: first principal surface, Principal surface Sa2: second principal surface, Side surface Sb1...first light incident surface, Side Sb2…Non-light incident surface, Side surface Sb3...first non-light incident surface, Side surface Sb4...second non-light incident surface, Side SI5 ... 1st side, Side SI7 ... second side, Side SI6 ... third side, Side SI8 ... 4th side, Side SI9 ... 5th side, Side SI1 ... 6th side, Side SI3 ... 7th side, Vertex V2: the first vertex, Vertex V1...second vertex.

[0085] Among the multiple sides in contact with the main surface Sa1, sides SI5 and SI6 are long sides, and sides SI7 and SI8 are short sides shorter than sides SI5 and SI6. Among the multiple sides in contact with the main surface Sa2, sides SI1 and SI2 are long sides, and sides SI3 and SI4 are short sides shorter than sides SI1 and SI2. Among the multiple sides in contact with the side surface Sb1, sides SI1 and SI5 are long sides, and sides SI9 and SI10 are short sides shorter than sides SI1 and SI5. Among the multiple sides in contact with the side surface Sb3, sides SI3 and SI7 are long sides, and sides SI9 and SI11 are short sides shorter than sides SI3 and SI7.

[0086] Fig. 15 is a cross-sectional view showing the transparent substrate ME1 taken along line XV-XV in Fig. 14. In the drawing, the dashed line indicates the outline of the transparent substrate ME1 before chamfering. As shown in Fig. 15, the shape of side surface Sb1 and the shape of side surface Sb2 are different from each other. Side surface Sb1 is a surface obtained by drawing a scribe line on a glass substrate and breaking the glass substrate. Side surface Sb1 is a fractured surface. Side surface Sb1 is a flat surface. Side surface Sb1 is not polished.

[0087] Since the light-emitting element LS emits light to the side surface Sb1, the transparent substrate ME1 can effectively propagate the light inside. For example, the light incident on the main surface Sa2 satisfies the condition of total reflection, so that the light incident on the transparent substrate ME1 is less likely to leak out from the main surface Sa2 to the outside.

[0088] In the transparent substrate ME1, a corner C5 located on the side SI5 and a corner C1 located on the side SI1 are not chamfered. Therefore, light incident on the transparent substrate ME1 is less likely to leak out from the main surface Sa2. In this embodiment, the corner C5 functions as a first corner, and the corner C1 functions as a sixth corner.

[0089] All side surfaces of the second base material 20, including the side surface Sc1, are fractured surfaces and are not polished surfaces (FIG. 2). Furthermore, the second base material 20 is not chamfered (FIG. 2).

[0090] However, when the corners C1 and C5 of the transparent substrate ME1 are chamfered or the side surface Sb1 is polished, the transparent substrate ME1 has difficulty in smoothly propagating light inside. For example, the light incident on the main surface Sa2 contains a component of light incident on the main surface Sa2 at an angle close to 90°, so that the light incident on the transparent substrate ME1 is likely to leak out from the main surface Sa2 to the outside.

[0091] To obtain the side surface Sb2, first, a scribe line is drawn on the glass substrate and the glass substrate is broken. Then, the side surface Sb2 is polished. Since the side surface Sb2 has an uneven surface, the side surface Sb2 is not flatter than the side surface Sb1. In other words, the surface roughness of the side surface Sb2 is greater than the surface roughness of the side surface Sb1. By polishing the side surface Sb2, for example, the size of the transparent substrate ME1 in the second direction Y can be adjusted.

[0092] In the transparent substrate ME1, a corner C6 located on the side SI6 and a corner C2 located on the side SI2 are chamfered. In this embodiment, the surface of the corner C6 is an inclined surface inclined from each of the main surface Sa1 and the side surface Sb2. The corner C6 functions as a third corner. The surface of the corner C2 is an inclined surface inclined from each of the main surface Sa2 and the side surface Sb2. The corners C5 and C1 are sharper than the corners C6 and C2, respectively.

[0093] The corners C6 and C2 of the transparent substrate ME1 are chamfered, which can suppress or prevent chipping caused by handling during the manufacture of the transparent substrate ME1 or during assembly of a module using the transparent substrate ME1.

[0094] Fig. 16 is a cross-sectional view showing the transparent substrate ME1 taken along line XVI-XVI in Fig. 14. In the drawing, the dashed line indicates the outline of the transparent substrate ME1 before chamfering. As shown in FIG. 16, the shape of the side surface Sb3 and the shape of the side surface Sb4 are different from the shape of the side surface Sb1.

[0095] To obtain the side surface Sb3, first, a scribe line is drawn on the glass substrate and the glass substrate is broken. Then, the side surface Sb3 is polished. The surface roughness of the side surface Sb3 is greater than the surface roughness of the side surface Sb1.

[0096] To obtain the side surface Sb4, first, a scribe line is drawn on the glass substrate and the glass substrate is broken. Then, the side surface Sb4 is polished. The surface roughness of the side surface Sb4 is greater than the surface roughness of the side surface Sb1. By polishing the side surface Sb3 and the side surface Sb4, for example, the size of the transparent substrate ME1 in the first direction X can be adjusted.

[0097] In the transparent substrate ME1, a corner C7 located on a side SI7, a corner C3 located on a side SI3, a corner C8 located on a side SI8, and a corner C4 located on a side SI4 are chamfered. The corner C7 functions as a second corner, the corner C8 functions as a fourth corner, and the corner C3 functions as a seventh corner.

[0098] In this embodiment, the surface of the corner C7 is an inclined surface inclined from each of the main surface Sa1 and the side surface Sb3. The surface of the corner C3 is an inclined surface inclined from each of the main surface Sa2 and the side surface Sb3. The surface of the corner C8 is an inclined surface inclined from each of the main surface Sa1 and the side surface Sb4. The surface of the corner C4 is an inclined surface inclined from each of the main surface Sa2 and the side surface Sb4.

[0099] Incidentally, corners C5 and C1 are sharper than corners C7, C3, C8, and C4, respectively (FIG. 15).

[0100] The transparent substrate ME1 has corners C7, C3, C8, and C4 chamfered, which can suppress or prevent chipping caused by handling during manufacturing of the transparent substrate ME1 or during assembly of a module using the transparent substrate ME1.

[0101] FIG. 17 is a cross-sectional view showing the transparent substrate ME1 of FIG. 14 taken along line XVII-XVII. 17, in the transparent substrate ME1, corner C9 located on side SI9, corner C10 located on side SI10, corner C11 located on side SI11, and corner C12 located on side SI12 are not chamfered. Corner C9 functions as a fifth corner.

[0102] Corners C9, C10, C11, and C12 are sharper than corners C6 and C2, respectively (FIG. 15). Corners C9 and C10 on both sides of side surface Sb1 are not chamfered. Compared to when corners C9 and C10 are chamfered, light can be propagated more satisfactorily inside transparent substrate ME1.

[0103] Fig. 18 is a cross-sectional view showing the transparent substrate ME1 taken along line XVIII-XVIII in Fig. 14. In the drawing, the dashed line indicates the outline of the transparent substrate ME1 before chamfering. 18, the transparent substrate ME1 has an apex P2 located at the apex V2, an apex P1 located at the apex V1, an apex P8 located at the apex V8, and an apex P3 located at the apex V3. The apex V2 functions as the first apex, and the apex V1 functions as the second apex. In addition, the apex P2 functions as the first apex, and the apex P1 functions as the second apex.

[0104] The apex P2, the apex P1, the apex P8, and the apex P3 are each chamfered. Although not shown, the apexes located at the apexes V6, V5, V4, and V3 are also chamfered.

[0105] Fig. 19 is an enlarged perspective view showing a part of the transparent substrate ME1 of Fig. 14. Here, the top part P2 will be described as a representative of the multiple top parts of the transparent substrate ME1. 19, the surface of the apex P2 is an inclined surface inclined from each of the main surface Sa1, the side surface Sb1, and the side surface Sb3. The surface of the apex P2 is also inclined from the surface of the corner C7. Therefore, the occurrence of the chipping can be further suppressed or prevented.

[0106] According to the display device DSP according to the first embodiment configured as described above, the display device DSP includes a display panel PNL, a transparent substrate ME1, an adhesive sheet AD1, and a first light source unit LU1. When the side surface Sb1 is polished or when the corners C1 and C5 are chamfered, it becomes difficult for the transparent substrate ME1 to smoothly propagate light therein.

[0107] If it becomes difficult to effectively propagate light inside the transparent substrate ME1, the amount of light becomes insufficient, making it difficult for the user to visually recognize the image (characters) displayed on the display device DSP. In addition, the brightness of the image displayed by the display device DSP tends to differ between the side surface Sb1 and the side surface Sb2.

[0108] Therefore, the shape of the side surface Sb1 is different from the shape of the side surface Sb3. The side surface Sb1 is a fracture surface. Light incident on the transparent substrate ME1 is less likely to leak out from the main surface Sa2 to the outside. In addition, corners C1 and C5 are not chamfered, which makes it even more difficult for light incident on the transparent substrate ME1 to leak outward from the main surface Sa2. This makes it easier for the user to visually recognize the image (character) displayed on the display device DSP, thereby making it possible to obtain a display device DSP that can improve the display quality.

[0109] Furthermore, in the manufacturing process of the display device DSP, the occurrence of chipping can be suppressed or prevented. Therefore, the display device DSP can be obtained with a high manufacturing yield. In addition to the above, various other preferable effects can be obtained from this embodiment.

[0110] (Modification of the first embodiment) Next, a modified example of the first embodiment will be described. The display device DSP is configured similarly to the display device DSP of the first embodiment, except for the configuration described in this modified example. Figure 20 is a cross-sectional view showing a transparent substrate ME1 according to this modified example. In the figure, the dashed line indicates the outline of the transparent substrate ME1 before chamfering.

[0111] 20, the chamfering of the corners of the transparent substrate ME1 is not limited to C-chamfering, and may be R-chamfering. The surface of corner C6 is a curved surface that protrudes outward from the transparent substrate ME1. The surface of corner C2 is a curved surface that protrudes outward from the transparent substrate ME1. In this modified example, the same effects as those of the first embodiment can be obtained.

[0112] Second embodiment Next, a second embodiment will be described. The display device DSP is configured similarly to the display device DSP of the first embodiment, except for the configuration described in this second embodiment. In this second embodiment, the display device DSP is not curved. FIG. 21 is a cross-sectional view showing the display device DSP according to this second embodiment. FIG. 22 is a plan view showing the cover panel CO1, the first light source unit LU1, and the second light source unit LU2 according to this second embodiment.

[0113] As shown in Fig. 21 and Fig. 22, the display device DSP includes a second light source unit LU2. The first light source unit LU1 and the second light source unit LU2 can irradiate light from both sides onto the transparent substrate ME1 and the second base material 20. The second base material 20 includes a side surface Sc2 located on the opposite side to the side surface Sc1. The light-emitting element LS of the second light source unit LU2 is located on the side surface Sc2 (side surface Sb2) side of the display area DA in the second direction Y, and can irradiate light toward the display area DA. The light-emitting element LS of the second light source unit LU2 faces the side surface Sb2 and has a light-emitting portion (light-emitting surface) EM that irradiates light onto the side surface Sb2.

[0114] Illumination light emitted from the light-emitting portion EM of the second light source unit LU2 is incident on the side surface Sb2 and propagates through the transparent substrate ME1 (cover panel CO1), the adhesive sheet AD1, and the display panel PNL. In the second embodiment, the light-emitting portion EM of the second light source unit LU2 also faces the side surface Sc2 of the second base material 20, and further irradiates light onto the side surface Sc2.

[0115] In the second embodiment, the side surface Sb2 functions as a second light incident surface. The side surface Sb3 is located between the side surfaces Sb1 and Sb2. The side surface Sb4 is located between the side surfaces Sb1 and Sb2.

[0116] FIG. 23 is a cross-sectional view showing the transparent substrate ME1 according to the second embodiment. As shown in Figures 23, 16, and 22, the shape of side Sb2 is different from the shapes of side Sb3 and Sb4. Side Sb2 is a surface obtained by drawing a scribe line on a glass substrate and breaking the glass substrate. Side Sb2 is a fractured surface. Side Sb2 is a flat surface. Side Sb2 is not polished. The surface roughness of side Sb3 and Sb4 is greater than the surface roughness of side Sb2.

[0117] Since the light-emitting element LS of the second light source unit LU2 irradiates the side surface Sb2 with light, the transparent substrate ME1 can effectively propagate the light inside. For example, since the light incident on the main surface Sa2 satisfies the condition of total reflection, the light incident on the transparent substrate ME1 is less likely to leak out from the main surface Sa2 to the outside.

[0118] The transparent substrate ME1 has corners C6 and C2 that are not chamfered. The corners C6 and C2 are sharper than the corners C7, C3, C8, and C4. This makes it even more difficult for light incident on the transparent substrate ME1 to leak outward from the main surface Sa2.

[0119] In the second embodiment, the same effects as those in the first embodiment can be obtained. Furthermore, the first light source unit LU1 and the second light source unit LU2 can be used to irradiate light onto both sides of the transparent substrate ME1. This makes it possible to suppress a decrease in the luminance level of the display device DSP.

[0120] (Modification 1 of the second embodiment) Next, a first modified example of the second embodiment will be described. The display device DSP has the same configuration as the display device DSP of the second embodiment, except for the configuration described in this first modified example. Fig. 24 is a cross-sectional view showing a transparent substrate ME1 according to the first modified example.

[0121] As shown in Fig. 24, the side surface Sb3 and the side surface Sb4, which are the non-light-entering surfaces of the transparent substrate ME1, are polished. The transparent substrate ME1 does not need to be chamfered. For example, corners C7, C3, C8, and C4 of the transparent substrate ME1 are not chamfered. Corners C7, C3, C8, and C4 are sharp like corners C5 and C1, respectively (Fig. 23). In the present modified example 1 as well, the same effects as those of the second embodiment can be obtained.

[0122] (Modification 2 of the second embodiment) Next, a second modification of the second embodiment will be described. The display device DSP has the same configuration as the display device DSP of the second embodiment, except for the configuration described in the second modification. Fig. 25 is a cross-sectional view showing a transparent substrate ME1 according to the second modification.

[0123] As shown in Fig. 25, the side surface Sb3 and the side surface Sb4, which are the non-light-entering surfaces of the transparent substrate ME1, do not need to be polished. The transparent substrate ME1 is chamfered. For example, corners C7, C3, C8, and C4 of the transparent substrate ME1 are chamfered. Corners C5 and C1 are sharper than corners C7, C3, C8, and C4, respectively (Fig. 23). In the present modified example 2 as well, the same effects as those of the second embodiment can be obtained.

[0124] (Third embodiment) Next, a third embodiment will be described. The display device DSP is configured similarly to the display device DSP of the first embodiment, except for the configuration described in this third embodiment. In this second embodiment, the display device DSP is not curved. FIG. 26 is a cross-sectional view showing the display device DSP according to this third embodiment. FIG. 27 is a plan view showing the cover panel CO1, the first light source unit LU1, and the optical member 70 of the display device DSP according to this third embodiment. FIG. 28 is a perspective view showing a part of the optical member 70 according to this third embodiment.

[0125] As shown in FIG. 26 and FIG. 27, the display device DSP further includes an optical member 70. The optical member 70 extends in the first direction X and is located between the side surface Sb1 of the transparent substrate ME1 and the first light source unit LU1 (light-emitting element LS). The light-emitting element LS irradiates light toward the optical member 70. The optical member 70 has a function of converging the light incident from the first light source unit LU1 and transmitting it to the side surface Sb1 side. In the YZ plane, the optical member 70 can increase the component of light traveling in a direction parallel to the second direction Y and transmit the light to the side surface Sb1. The optical member 70 can also restrict light in the thickness direction (third direction Z). For example, the light incident on the transparent substrate ME1 is less likely to leak out from the main surface Sa2 to the outside. Therefore, the light can be well propagated inside the transparent substrate ME1 to the side surface Sb2 side.

[0126] In this embodiment, the optical member 70 is also located between the side surface Sc1 of the second base material 20 and the first light source unit LU1 (light-emitting element LS). The optical member 70 can also focus light incident from the first light source unit LU1 and transmit it to the side surface Sc1.

[0127] As shown in Fig. 28, the optical member 70 is a microlens array having a plurality of arranged microlenses 71 and a plate-shaped transparent layer 72. The plurality of microlenses 71 and the transparent layer 72 are integrally formed. Each microlens 71 is raised so as to be convex toward the side surface Sb1 or the side surface Sc1. In a plan view of the optical member 70 seen from the side surface Sb1 side, the shape of the microlens 71 is quadrangular. However, in a plan view, the shape of the microlens 71 may be a polygon other than a quadrangle, such as a hexagon, or may be circular.

[0128] The display device DSP according to the third embodiment configured as above can also obtain the same effects as those of the first embodiment, and can obtain a display device DSP capable of improving display quality. By providing the optical member 70, the components of light perpendicularly incident on the side surfaces Sb1 and Sc1 can be increased. The light emitted from the light emitting element LS can be efficiently input (transmitted) into the inside of the transparent substrate ME1 and the inside of the second base material 20. Therefore, the user can view the display image of the display device DSP more satisfactorily. Alternatively, the power consumption of the first light source unit LU1 can be reduced. The optical member 70 may be a lenticular lens.

[0129] 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.

[0130] For example, the first color, the second color, and the third color are not limited to red, green, and blue, respectively. The light source unit LU may include light-emitting elements LS of two or less colors, or may include light-emitting elements LS of four or more colors. Alternatively, the light source unit LU may include white light-emitting elements LS. The number of line memories, subframe data, and subframe periods may be increased or decreased depending on the number of types (number of colors) of the light-emitting elements LS.

[0131] A normal type polymer dispersed liquid crystal may be used for the liquid crystal layer 30. The liquid crystal layer 30 maintains the parallelism of incident light when a high voltage is applied, and scatters the incident light when a low voltage is applied.

[0132] The first substrate 10 and the second substrate 20 of the display panel PNL may each be formed of a resin. In that case, it is preferable that the first substrate 10 and the second substrate 20 are each formed of an amorphous resin. An example of the amorphous resin is cycloolefin polymer (COP). By forming the first substrate 10 and the second substrate 20 from an amorphous resin, scattering of light inside the first substrate 10 and the second substrate 20 can be suppressed, and light can be guided well.

[0133] The first base material 10 and the second base material 20 may each be made of a crystalline resin. An example of the crystalline resin is polyethylene terephthalate (PET). [Explanation of symbols]

[0134] DSP: display device, PNL: display panel, SUB1: first substrate, SUB2: second substrate, 10...first substrate, 20...second substrate, 30...liquid crystal layer, 31...liquid crystal polymer, 32... liquid crystal molecule, PX... pixel, SW... switching element, G... gate line, S... source line, 11... pixel electrode, 21... common electrode, CO1... cover panel, ME1: transparent substrate; Sa1, Sa2, Sa3, Sa4: main surface; Sb1 to Sb4: side surface; SI1~SI12...sides, C1~C12...corners, V1~V8...vertices, P1, P2, P3, P8...top, AD1...adhesive sheet, LU1...first light source unit, LU2: second light source unit; LS: light emitting element; 70: optical member; 71: microlens; 72...transparent layer, DA...display area, NDA...non-display area, X...first direction, Y...second direction, Z…Third direction.

Claims

1. a display panel having a display area for displaying an image and transmitting external light; a transparent substrate overlapping the display region and having a first main surface having a first side and a second side, a first light-entering surface being a side surface contacting the first main surface at the first side, and a first non-light-entering surface being another side surface contacting the first main surface at the second side; a fixing member positioned between the transparent substrate and the display panel, the fixing member fixing the display panel to the transparent substrate; a first light source unit that faces the first light incident surface of the transparent substrate and irradiates the first light incident surface with light, The shape of the first light-entering surface and the shape of the first non-light-entering surface are different from each other. Display device.

2. The first light entrance surface is a fractured surface. The display device according to claim 1 .

3. The surface roughness of the first non-light-entering surface is greater than the surface roughness of the first light-entering surface. The display device according to claim 1 .

4. Further comprising a second light source unit, the transparent substrate further has a second light incident surface which is another side surface in contact with the first main surface at a third side and is located on the opposite side to the first light incident surface, the first non-light-entering surface is located between the first light-entering surface and the second light-entering surface, the second light source unit faces the second light incident surface of the transparent substrate and irradiates light onto the second light incident surface; The shape of the second light-entering surface and the shape of the first non-light-entering surface are different from each other. The display device according to claim 1 .

5. The second light entrance surface is a fractured surface. The display device according to claim 4.

6. the transparent substrate further has a second non-light-entering surface that is another side surface in contact with the first main surface at a fourth side and is located on the opposite side to the first non-light-entering surface, The shape of the second light-entering surface and the shape of the second non-light-entering surface are different from each other. The display device according to claim 4.

7. The surface roughness of the second non-light-entering surface is greater than the surface roughness of the second light-entering surface. The display device according to claim 6.

8. The transparent substrate has a rectangular plate shape, Among the multiple sides contacting the first main surface, The first side is a long side, The second side is a shorter side than the first side. The display device according to claim 1 .

9. a display panel having a display area for displaying an image and transmitting external light; a transparent substrate overlapping the display region and having a first main surface having a first side and a second side, a first light-entering surface being a side surface contacting the first main surface at the first side, and a first non-light-entering surface being another side surface contacting the first main surface at the second side; a fixing member positioned between the transparent substrate and the display panel, the fixing member fixing the display panel to the transparent substrate; a first light source unit that faces the first light incident surface of the transparent substrate and irradiates the first light incident surface with light, the transparent substrate further has a first corner portion located on the first side and a second corner portion located on the second side, The second corner portion has a chamfered shape, The first corner is sharper than the second corner. Display device.

10. The surface of the second corner portion is a curved surface protruding outward from the transparent substrate, or an inclined surface inclined from each of the first main surface and the first non-light-entering surface. The display device according to claim 9.

11. Further comprising a second light source unit, the transparent substrate further has a second light incident surface which is another side surface in contact with the first main surface at a third side and is located on the opposite side to the first light incident surface, the first non-light-entering surface is located between the first light-entering surface and the second light-entering surface, the second light source unit faces the second light incident surface of the transparent substrate and irradiates light onto the second light incident surface; the transparent substrate further has a third corner portion located on the third side, The third corner is sharper than the second corner. The display device according to claim 9.

12. the transparent substrate further includes a second non-light-entering surface that is another side surface in contact with the first main surface at a fourth side and is located on the opposite side to the first non-light-entering surface, and a fourth corner portion located on the fourth side, The fourth corner portion has a chamfered shape, The third corner is sharper than the fourth corner. The display device according to claim 11.

13. the transparent substrate further has a fifth corner portion located on a fifth side where the first light incident surface and the first non-light incident surface are in contact, The fifth corner is sharper than the second corner. The display device according to claim 9.

14. the transparent substrate further has a first apex located at a first apex where the first side, the second side, and the fifth side meet, The first apex has a chamfered shape. The display device according to claim 13.

15. the transparent substrate further has a second main surface located on the opposite side to the first main surface, the second main surface being in contact with the first light-entering surface at a sixth side and the first non-light-entering surface at a seventh side, a sixth corner portion located on the sixth side, and a seventh corner portion located on the seventh side, The seventh corner portion has a chamfered shape, The sixth corner is sharper than the seventh corner. The display device according to claim 13.

16. the transparent substrate further has a second apex located at a second apex where the fifth side, the sixth side, and the seventh side meet, The second apex has a chamfered shape, The display device according to claim 15.

17. The transparent substrate has a rectangular plate shape, Among the multiple sides contacting the first main surface, The first side is a long side, The second side is a shorter side than the first side. The display device according to claim 9.

18. The shape of the first light-entering surface and the shape of the first non-light-entering surface are different from each other. The display device according to claim 9.

19. The first light entrance surface is a fractured surface. The display device according to claim 18.

20. The surface roughness of the first non-light-entering surface is greater than the surface roughness of the first light-entering surface. The display device according to claim 18.

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