Display device

Abstract

To provide a display device that can suppress deterioration in display quality.SOLUTION: A display device comprises a first substrate, a second substrate, a liquid crystal layer, a plurality of light-emitting elements arranged in a first direction, a third transparent substrate having a side surface opposing the plurality of light-emitting elements, and a transparent layer having a refractive index lower than that of the third transparent substrate. The third transparent substrate includes, in a plan view, a straight portion located on a side opposing the light-emitting elements and along the first direction, and a curved portion opposing the straight portion in a second direction. The transparent layer includes a plurality of strip portions arranged side by side in the first direction and extending in the second direction. Each of the plurality of strip portions has a first end portion on the side opposing the light-emitting elements and a second end portion on an opposite side to the first end portion. A width of the first end portion is larger than a width of the second end portion, and each of the plurality of strip portions has the same width along the first direction at a location of an equal distance from the straight portion along the second direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a display device. [Background technology]

[0002] Various display devices using polymer-dispersed liquid crystals have been proposed that can switch between a scattering state that scatters incident light and a transparent state that transmits incident light. Display devices using polymer-dispersed liquid crystals sometimes use an edge-light system in which a light-emitting module is located at the edge of the display panel. Because such display devices have high transmittance, they are expected to be used in a variety of fields. However, there is a demand for improvements to be made to the phenomenon in which brightness decreases with increasing distance from the light-emitting module. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-180535 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present embodiment is to provide a display device capable of suppressing degradation in display quality. [Means for solving the problem]

[0005] According to one embodiment, a display device includes a first substrate including a first transparent substrate and pixel electrodes arranged on the first transparent substrate for each of a plurality of pixels; a second substrate including a second transparent substrate; a liquid crystal layer arranged between the first substrate and the second substrate and including striated polymer and liquid crystal molecules; a third transparent substrate having a plurality of light-emitting elements aligned in a first direction and a side surface facing the plurality of light-emitting elements; and a transparent layer arranged between the second substrate and the third transparent substrate and having a refractive index lower than that of the third transparent substrate, wherein the third transparent substrate has a refractive index of a straight portion located on the side facing the light-emitting element and extending along the first direction, and a curved portion facing the immediately preceding portion in a second direction perpendicular to the first direction, the transparent layer having a plurality of band portions arranged in a line in the first direction and extending in the second direction, each of the plurality of band portions having a first end portion on the side facing the light-emitting element and a second end portion opposite the first end portion, the width of the first end portion being greater than the width of the second end portion, and each of the plurality of band portions having the same width along the first direction at a position equidistant from the straight portion along the second direction. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view showing an example of the configuration of a display device DSP according to this embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing the main part of the display device DSP shown in FIG. [Figure 3] FIG. 3 is a cross-sectional view showing an example of the configuration of the display device DSP shown in FIG. [Figure 4] FIG. 4 is a plan view showing an example of the configuration of the light guide element LG shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing an example of the configuration of the display device DSP of this embodiment. [Figure 6] FIG. 6 is a plan view showing a light guide element LG' of a comparative example. [Figure 7] FIG. 7 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. [Figure 8] FIG. 8 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. [Figure 9] FIG. 9 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. [Figure 10] FIG. 10 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] The present embodiment will be described below with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily make while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment for clarity of explanation, but these are merely examples and are not intended to limit the interpretation of the present invention. Furthermore, in this specification and each drawing, components that perform the same or similar functions as those described above with reference to the previous drawings are designated by the same reference numerals, and redundant detailed descriptions may be omitted as appropriate.

[0008] FIG. 1 is a plan view showing an example of the configuration of the display device DSP of this embodiment. In one example, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but they may intersect at an angle other than 90 degrees. The first direction X and the second direction Y correspond to directions parallel to the main surfaces of the substrates constituting the display device DSP, and the third direction Z corresponds to the thickness direction of the display device DSP. In this specification, the direction from the first substrate SUB1 to the second substrate SUB2 is referred to as the "upper side" (or simply "up"), and the direction from the second substrate SUB2 to the first substrate SUB1 is referred to as the "lower side" (or simply "lower"). When referring to a "second member above the first member" and a "second member below the first member," the second member may be in contact with the first member or may be spaced apart from the first member. Furthermore, the tip of the arrow indicating the third direction Z is assumed to be an observation position for observing the display device DSP, and viewing from this observation position toward the XY plane defined by the first direction X and the second direction Y is referred to as planar viewing.

[0009] In this embodiment, a liquid crystal display device using a polymer dispersed liquid crystal will be described as an example of the display device DSP. The display device DSP includes a display panel PNL, an IC chip 1, and a wiring substrate 2.

[0010] The display panel PNL includes a first substrate SUB1, a second substrate SUB2, a liquid crystal layer LC, and a seal SE. The first substrate SUB1 and the second substrate SUB2 are formed as flat plates parallel to the XY plane. The first substrate SUB1 has a straight portion S1 extending along the first direction X and a curved portion C1 facing the straight portion S1 in the second direction Y. The second substrate SUB2 has a straight portion S2 extending along the first direction X and a curved portion C2 facing the straight portion S2 in the second direction Y. The curved portion C2 overlaps the curved portion C1 in a plan view. The straight portion S2 does not overlap the straight portion S1. The first substrate SUB1 has an extending portion Ex extending from the straight portion S2 in the second direction Y in a plan view.

[0011] The first substrate SUB1 and the second substrate SUB2 overlap in a plan view. The first substrate SUB1 and the second substrate SUB2 are bonded together by a seal SE. The extension portion Ex does not overlap with the second substrate SUB2 in a plan view. The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2 and is sealed by the seal SE. In FIG. 1, the liquid crystal layer LC and the seal SE are indicated by different diagonal lines.

[0012] As schematically shown in an enlarged view in FIG. 1, the liquid crystal layer LC includes a polymer-dispersed liquid crystal including a polymer 51 and liquid crystal molecules 52. In one example, the polymer 51 is a liquid crystal polymer. The polymer 51 is formed in stripes extending along a first direction X. The liquid crystal molecules 52 are dispersed in gaps between the polymer 51 and are oriented with their major axes aligned along the first direction X. Each of the polymer 51 and the liquid crystal molecules 52 has optical anisotropy or refractive index anisotropy. The responsiveness of the polymer 51 to an electric field is lower than that of the liquid crystal molecules 52 to an electric field.

[0013] In one example, the alignment direction of the polymer 51 hardly changes regardless of the presence or absence of an electric field. On the other hand, the alignment direction of the liquid crystal molecules 52 changes in response to an electric field when a high voltage equal to or greater than a threshold value is applied to the liquid crystal layer LC. When no voltage is applied to the liquid crystal layer LC, the optical axes of the polymer 51 and the liquid crystal molecules 52 are parallel to each other, and light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC with almost no scattering within the liquid crystal layer LC (transparent state). When a voltage is applied to the liquid crystal layer LC, the optical axes of the polymer 51 and the liquid crystal molecules 52 intersect with each other, and light incident on the liquid crystal layer LC is scattered within the liquid crystal layer LC (scattered state).

[0014] The display panel PNL includes a display section DA that displays an image in an area where the first substrate SUB1 and the second substrate SUB2 overlap in a plan view, and a non-display section NDA that surrounds the display section DA. The seal SE is located in the non-display section NDA. In the example shown in Fig. 1, the display section DA has an edge section E1 that is adjacent to the straight section S2 and extends along the first direction X, and an edge section E2 that is adjacent to the curved section C2 and faces the straight section S2 in the second direction Y. The display section DA includes pixels PX that are arranged in a matrix in the first direction X and the second direction Y.

[0015] As shown enlarged in FIG. 1, each pixel PX includes a switching element SW, a pixel electrode PE, a common electrode CE, a liquid crystal layer LC, etc. The switching element SW is formed, for example, by a thin film transistor (TFT) and is electrically connected to a scanning line G and a signal line S. The scanning line G extends in a first direction X and is electrically connected to the switching element SW in each of the pixels PX aligned in the first direction X. The signal line S extends in a second direction Y, intersects with the scanning line G, and is electrically connected to the switching element SW in each of the pixels PX aligned in the second direction Y. The pixel electrode PE is electrically connected to the switching element SW. Each pixel electrode PE faces the common electrode CE, and the liquid crystal layer LC (particularly, liquid crystal molecules 52) is driven by an electric field generated between the pixel electrode PE and the common electrode CE. The capacitance CS is formed, for example, between an electrode having the same potential as the common electrode CE and an electrode having the same potential as the pixel electrode PE.

[0016] The IC chip 1 and the wiring board 2 are each connected to the extension portion Ex. The IC chip 1 has built-in, for example, a display driver that outputs signals necessary for image display. The wiring board 2 is a bendable flexible printed circuit board. The IC chip 1 may be connected to the wiring board 2. The IC chip 1 and the wiring board 2 may read signals from the display panel PNL, but they mainly function as signal sources that supply signals to the display panel PNL.

[0017] Fig. 2 is an exploded perspective view showing the main part of the display device DSP shown in Fig. 1. In Fig. 2, the side surface of the second substrate SUB2 along the linear portion S2 is shown transparently by a dotted line.

[0018] The display device DSP includes a light guide element LG and a light emitting module LM in addition to the display panel PNL. The first substrate SUB1, the second substrate SUB2, and the light guide element LG are arranged in this order along the third direction Z.

[0019] The light emitting module LM includes a plurality of light emitting elements LD, a light guide LB, and a wiring board F.

[0020] The plurality of light-emitting elements LD are arranged at intervals in the first direction X. Each of the plurality of light-emitting elements LD is connected to a wiring substrate F. In the example shown in FIG. 2, each of the plurality of light-emitting elements LD overlaps the extension portion Ex in a planar view. The light-emitting element LD is, for example, a light-emitting diode. Although not described in detail, the light-emitting element LD includes a red light-emitting portion, a green light-emitting portion, and a blue light-emitting portion. Light emitted from the light-emitting element LD travels along the direction of the arrow indicating the second direction Y. The light guide body LB is formed in a rod shape extending in the first direction X, and is disposed between the light-emitting element LD and the light-guiding element LG in the second direction Y.

[0021] The light guide element LG includes a transparent substrate 30 and a transparent layer 40.

[0022] The transparent substrate 30 has a straight portion S3 extending along the first direction X and a curved portion C3 opposing the straight portion S3 in the second direction Y. The straight portion S3 is located on the side of the transparent substrate 30 facing the light-emitting element LD. The straight portion S3 has one end 33b along the first direction X and another end 33c opposite the one end 33b. A position equidistant from the one end 33b and the other end 33c is referred to as the center 33a of the straight portion S3. In the example shown in FIG. 2, the distance R1 from the center 33a of the straight portion S3 to the one end 33b of the straight portion S3 is equal to the distance R2 from the center 33a of the straight portion S3 to the curved portion C3 along the second direction Y. In the example shown, the curved portion C3 is formed in an arc shape, and the transparent substrate 30 has a semicircular shape in a plan view. The curved portions C1, C2, and C3 overlap in a plan view. The straight portions S2 and S3 overlap in a plan view. The straight portion S3 is located between the straight portion S1 and the display portion DA in a plan view.

[0023] 2, each of the first substrate SUB1, the second substrate SUB2, and the light guide element LG includes a reflective member RM disposed on the side surface along the curved portions C1, C2, and C3. The reflective member RM is formed of a metal material with high reflectivity, such as aluminum, silver, or titanium. The reflective member RM may be a sheet adhered to the side surface, or may be a thin film formed directly on the side surface by a method such as vapor deposition.

[0024] The transparent substrate 30 has a side surface 31 along the straight portion S3. The side surface 31 is a plane that is approximately parallel to the XZ plane defined by the first direction X and the third direction Z. In a plan view, the side surface 31 is located on the side facing the light-emitting element LD, and faces the plurality of light-emitting elements LD in the second direction Y via the light guide LB. The transparent substrate 30 also has a side surface 32 along the curved portion C3. The side surface 32 faces the side surface 31 in the second direction Y.

[0025] The transparent layer 40 is disposed between the transparent substrate 30 and the second substrate SUB2. In the illustrated example, the transparent layer 40 is formed on the surface of the transparent substrate 30 facing the second substrate SUB2. The transparent layer 40 may also be formed on the surface of the second substrate SUB2 facing the transparent substrate 30. The transparent layer 40 includes a plurality of band portions 41 aligned in the first direction X. Each of the band portions 41 extends along the second direction Y and is formed in a generally isosceles triangle shape.

[0026] When the display panel PNL and the light guide element LG shown in FIG. 2 are overlapped, the plurality of strip portions 41 overlap the display portion DA in a plan view.

[0027] Fig. 3 is a cross-sectional view showing an example of the configuration of the display device DSP shown in Fig. 1. Here, a cross section of the display unit DA in the XZ plane defined by the first direction X and the third direction Z will be described.

[0028] The first substrate SUB1 includes a transparent substrate 10, insulating films 11, 12, and 13, a capacitance electrode 14, metal lines ML, signal lines S, pixel electrodes PE, and an alignment film AL1. The first substrate SUB1 further includes the switching elements SW and scanning lines G shown in FIG. 1. The scanning lines G are disposed, for example, between the transparent substrate 10 and the insulating film 11.

[0029] The transparent substrate 10 has a main surface (lower surface) 10A and a main surface (upper surface) 10B opposite to the main surface 10A. The main surfaces 10A and 10B are surfaces that are approximately parallel to the XY plane. An insulating film 11 covers the main surface 10B. The signal lines S are disposed on the insulating film 11.

[0030] The insulating film 12 covers the signal lines S. Although not described in detail, the insulating film 12 is formed in a lattice shape overlapping the scanning lines G and the signal lines S. The capacitance electrodes 14 are disposed on the insulating film 12. The metal lines ML are disposed on the capacitance electrodes 14. Although not described in detail, the capacitance electrodes 14 and the metal lines ML are formed in a lattice shape overlapping the insulating film 12.

[0031] The insulating film 13 covers the insulating film 11, the capacitance electrode 14, and the metal line ML. The pixel electrode PE is arranged on the insulating film 13 for each pixel PX. The pixel electrode PE is electrically connected to the switching element SW. The pixel electrode PE faces the capacitance electrode 14 via the insulating film 13, forming a capacitance CS of the pixel PX. The alignment film AL1 covers the pixel electrode PE and the insulating film 13.

[0032] The second substrate SUB2 includes a transparent substrate 20, a light-shielding layer BM, a common electrode CE, and an alignment film AL2.

[0033] The transparent substrate 20 has a main surface (lower surface) 20A and a main surface (upper surface) 20B opposite to the main surface 20A. The main surfaces 20A and 20B are surfaces that are approximately parallel to the XY plane. The main surface 20A of the transparent substrate 20 faces the main surface 10B of the transparent substrate 10.

[0034] The light-shielding layer BM and the common electrode CE are disposed on the main surface 20A. The light-shielding layer BM is located, for example, directly above the signal lines S and directly above the switching elements SW and scanning lines G (not shown). The common electrode CE is disposed across multiple pixels PX, faces each of the pixel electrodes PE in the third direction Z via the liquid crystal layer LC, and directly covers the light-shielding layer BM. The common electrode CE is electrically connected to the capacitance electrode 14 and has the same potential as the capacitance electrode 14.

[0035] The alignment film AL2 covers the common electrode CE. The liquid crystal layer LC is located between the main surface 10B and the main surface 20A, and is in contact with the alignment films AL1 and AL2.

[0036] On the first substrate SUB1, the insulating films 11, 12, and 13, the capacitance electrode 14, the signal line S, the pixel electrode PE, and the alignment film AL1 are located between the main surface 10B and the liquid crystal layer LC. On the second substrate SUB2, the light-shielding layer BM, the common electrode CE, and the alignment film AL2 are located between the main surface 20A and the liquid crystal layer LC.

[0037] The transparent substrates 10 and 20 are insulating substrates such as glass substrates or plastic substrates. The insulating film 11 is an inorganic insulating film made of silicon oxide, silicon nitride, silicon oxynitride, or the like. The insulating film 12 is an organic insulating film made of, for example, acrylic resin, or the like. The insulating film 13 is an inorganic insulating film made of silicon nitride.

[0038] The capacitance electrode 14, the pixel electrode PE, and the common electrode CE are transparent electrodes formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The light-shielding layer BM may be a conductive layer or an insulating layer.

[0039] The alignment films AL1 and AL2 are horizontal alignment films having an alignment restriction force substantially parallel to the XY plane. In one example, the alignment films AL1 and AL2 are subjected to an alignment treatment along the first direction X. The alignment treatment may be a rubbing treatment or a photo-alignment treatment.

[0040] The light guide element LG includes a transparent substrate 30 and a transparent layer 40.

[0041] The transparent substrate 30 is an insulating substrate and has a refractive index n1. The transparent substrate 30 is, for example, a glass substrate, but may also be a plastic substrate made of polymethyl methacrylate (PMMA), polycarbonate (PC), or the like. In one example, the transparent substrate 30 is a single substrate rather than a laminate of multiple substrates. The transparent substrate 30 has a main surface (lower surface) 30A and a main surface (upper surface) 30B opposite to the main surface 30A. The main surfaces 30A and 30B are surfaces approximately parallel to the XY plane. The main surface 30A faces the main surface 20B of the transparent substrate 20.

[0042] The transparent layer 40 is disposed on the main surface 30A. The transparent layer 40 is formed of an organic material such as a siloxane-based resin or a fluorine-based resin. The transparent layer 40 has a plurality of strip portions 41 arranged in a first direction X. Each of the strip portions 41 extends along a second direction Y. The main surface 30A is exposed between adjacent strip portions 41. In the example shown in FIG. 3, the strip portions 41 are located above the signal lines S and overlap each other in a planar view. The detailed shape of the transparent layer 40 will be described later.

[0043] 3, the transparent substrate 30 is adhered to the transparent substrate 20 of the second substrate SUB2 by a transparent adhesive layer AD. The transparent adhesive layer AD contacts almost the entire main surface 20B, covers the transparent layer 40, and contacts the main surface 30A in areas where the transparent layer 40 is missing.

[0044] The transparent substrate 10 has a thickness T1, the transparent substrate 20 has a thickness T2, the transparent substrate 30 has a thickness T3, the transparent layer 40 has a thickness T4, and the transparent adhesive layer AD has a thickness T5. Note that the thickness in this specification corresponds to the length along the third direction Z.

[0045] In the illustrated example, thickness T1 is equal to thickness T2, and thickness T3 is thicker than thicknesses T1 and T2. Note that thickness T3 may be equal to thicknesses T1 and T2. In one example, thickness T3 is 200 μm to 2000 μm. Thickness T4 of transparent layer 40 is equal to or less than the maximum wavelength of light L1 emitted from light-emitting element LD, which will be described later. In one example, thickness T4 is 250 nm to 1500 nm. Thickness T5 of transparent adhesive layer AD is 4 μm to 4000 μm.

[0046] The transparent layer 40 has a refractive index n2 that is smaller than the refractive index n1 of the transparent substrate 30. The refractive index n1 of the transparent substrate 30 is approximately 1.5, and the refractive index n2 of the transparent layer 40 is approximately 1.0 to 1.4. The refractive indices of the transparent substrates 10 and 20 and the transparent adhesive layer AD are equivalent to the refractive index n1 of the transparent substrate 30 and higher than the refractive index n2 of the transparent layer 40. Here, "equivalent" does not necessarily mean that the difference in refractive index is zero, but also includes cases where the difference in refractive index is 0.03 or less.

[0047] Fig. 4 is a plan view showing a configuration example of the light guide element LG shown in Fig. 3. In Fig. 4, the band portion 41 is shown schematically with an enlarged width in the first direction X. In Fig. 4, the area that overlaps with the display unit DA when the light guide element LG overlaps with the display panel PNL shown in Fig. 2 is shown by a dashed dotted line. The strip portion 41 has a first end portion 411 facing the light emitting element LD, a second end portion 412 opposite the first end portion 411, a first edge 413, and a second edge 414. The strip portions 41 are arranged side by side in the first direction X. The first end portions 411 are arranged on the same straight line along the first direction X.

[0048] With regard to the length of each of the band portions 41 along the second direction Y, the length of the band portion 41a extending in the second direction Y from near the center 33a of the straight portion S3 is the longest, and the lengths of the band portion 41b extending in the second direction Y from near one end 33b of the straight portion S3 and the band portion 41c extending in the second direction Y from near the other end 33c are the shortest. Furthermore, the length of the band portion 41 gradually shortens from the band portion 41a to the band portion 41b, and similarly, the length of the band portion 41 gradually shortens from the band portion 41a to the band portion 41c.

[0049] 4, each of the first ends 411 overlaps an edge E1 of the display unit DA in a plan view, and each of the second ends 412 overlaps an edge E2 of the display unit DA in a plan view, but this is not limiting. From the perspective of suppressing light leakage between the straight line portion S3 and the display unit DA, it is desirable that each of the first ends 411 be close to the straight line portion S3 beyond the display unit DA.

[0050] Each of the first end 411 and the second end 412 has a first width W1 and a second width W2. In this specification, the width corresponds to the length along the first direction X. The first width W1 is larger than the second width W2. In one example, the first width W1 is smaller than the width WLD of one light-emitting element LD, and one light-emitting element LD is arranged across multiple strip portions 41 aligned in the first direction X. In addition, the first width W1 is equal to or smaller than the width WP of one pixel electrode PE (or the pitch of the pixel electrodes PE aligned in the first direction X).

[0051] The first width W1 is substantially the same for all of the band portions 41. On the other hand, the second width W2 of the band portion 41a is smaller than the second width W2 of each of the band portions 41b and 41c.

[0052] The first edge 413 and the second edge 414 extend in directions different from the first direction X and the second direction Y between the first end 411 and the second end 412. For example, a direction intersecting the second direction Y at an acute angle in a clockwise direction is defined as direction D1, and a direction intersecting the second direction Y at an acute angle in a counterclockwise direction is defined as direction D2. Note that the angle θ1 between the second direction Y and direction D1 and the angle θ2 between the second direction Y and direction D2 are the same, but this is not limiting, and the angle between the second direction Y and direction D1 and the angle between the second direction Y and direction D2 may be different.

[0053] The first edge 413 extends along direction D1, and the second edge 414 extends along direction D2. Here, the first edge 413 and the second edge 414 both extend linearly, but they may also be formed in curved shapes. The first width W1 and the second width W2 correspond to the distance between the first edge 413 and the second edge 414 in the first direction X.

[0054] The strip portions 41 having this shape have a width that gradually decreases at a constant rate or an arbitrary rate from the first end portion 411 to the second end portion 412. Each of the strip portions 41 has the same width WL along the first direction X at a position that is equidistant L along the second direction Y from the straight portion S3. The position of equidistant L is a position closer to the curved portion C3 than the first end portion 411, and the distance L is, for example, approximately 1 / 4 to 1 / 2 of the distance R2 shown in FIG. 2. The pitch between adjacent strip portions 41 is preferably equal to or less than twice the width WP of the pixel electrode PE (or the pitch of the pixel electrodes PE aligned in the first direction X).

[0055] The pixel electrode PE overlaps two adjacent strip portions 41 in plan view. The pixel electrode PE overlaps the main surface 30A of the transparent substrate 30 between the strip portions 41.

[0056] In the display unit DA, attention is focused on the pixel electrode PE1 closest to the light-emitting element LD and the pixel electrode PE2 farthest from the light-emitting element LD. The area where the pixel electrode PE1 overlaps with the transparent layer 40 is larger than the area where the pixel electrode PE2 overlaps with the transparent layer 40. In other words, the area where the main surface 30A and the pixel electrode PE1 overlap without the transparent layer 40 is smaller than the area where the main surface 30A and the pixel electrode PE2 overlap without the transparent layer 40. In this way, the overlapping area between the pixel electrode PE and the transparent layer 40 is larger in the region close to the light-emitting element LD than in the region farther from the light-emitting element LD.

[0057] Furthermore, among the pixel electrodes PE located in the display area DA at a distance L from the straight line portion S3 in the second direction Y, attention is focused on the pixel electrode PE3 located in the center in the first direction X and the pixel electrode PE4 located at an end in the first direction X. The area where the pixel electrode PE3 overlaps with the transparent layer 40 is equal to the area where the pixel electrode PE4 overlaps with the transparent layer 40. Furthermore, the area where the pixel electrode PE3 overlaps with the main surface 30A is equal to the area where the pixel electrode PE4 overlaps with the main surface 30A.

[0058] As will be described later, the area overlapping the transparent layer 40 corresponds to an area where almost no light from the light-emitting element LD enters the display panel PNL, and the area overlapping the main surface 30A without going through the transparent layer 40 corresponds to an area where light from the light-emitting element LD can enter the display panel PNL.

[0059] Fig. 5 is a cross-sectional view showing an example of the configuration of the display device DSP shown in Fig. 1. Note that only the main part of the display panel PNL is shown. With reference to Fig. 5, the light emitted from the light emitting element LD will be described. The light emitting element LD emits light L1 toward the side surface 31. After transmitting through the light guide LB, the light L1 emitted from the light emitting element LD is refracted at the side surface 31 and enters the transparent substrate 30. Of the light L1 that enters the transparent substrate 30, a portion of the light that travels from the transparent substrate 30 toward the transparent layer 40 is reflected at the interface between the transparent substrate 30 and the transparent layer 40 and does not reach the second substrate SUB2, the liquid crystal layer LC, or the first substrate SUB1. Furthermore, of the light that travels from the transparent substrate 30 toward the transparent layer 40, light that has an incident angle smaller than the critical angle transmits through the transparent layer 40 and reaches the liquid crystal layer LC, as indicated by the dashed line.

[0060] Furthermore, of the light L1 incident on the transparent substrate 30, the light traveling toward the main surface 30B is reflected at the interface between the transparent substrate 30 and the air layer. In this way, most of the light L1 travels inside the transparent substrate 30 while being repeatedly reflected near the side surface 31 (or the region where the transparent layer 40 is present). Of the traveling light L1, the light traveling toward the region where the transparent layer 40 is not present, i.e., the region where the transparent substrate 30 and the transparent adhesive layer AD are in contact, passes through the transparent substrate 30 and then passes through the transparent substrate 20 via the transparent adhesive layer AD.

[0061] The liquid crystal layer LC of a pixel to which a voltage is applied scatters the light L1, while the liquid crystal layer LC of a pixel to which no voltage is applied transmits the light L1.

[0062] 5, when a reflecting member RM is provided on the opposite side of the light emitting element LD, for example, light L1 that reaches the side surface 32 is reflected by the reflecting member RM toward the display unit. This prevents light from leaking from the side surface 32, and improves the utilization efficiency of light L1 compared to when the reflecting member RM is not provided.

[0063] As described with reference to FIG. 4, the overlapping area between the pixel electrode PE and the strip portion 41 is larger in the region close to the light-emitting element LD than in the region away from the light-emitting element LD. Therefore, in the region close to the light-emitting element LD, the incidence of light L1 on the pixel electrode PE is suppressed, while in the region away from the light-emitting element LD, the incidence of light L1 on the pixel electrode PE is promoted. Note that in the region close to the light-emitting element LD, the light L1 is not completely blocked from entering the display panel PNL. As shown in FIG. 4, the light L1 enters the display panel PNL through gaps between adjacent strip portions 41, and light with an incident angle outside the total reflection condition also enters the display panel PNL. In regions spaced the same distance L from the light-emitting element LD, the overlapping area between the pixel electrode PE and the transparent layer 40 is the same. Therefore, in regions spaced the same distance L from the light-emitting element LD, the light L1 is incident on each pixel electrode PE to the same extent.

[0064] Of the light incident on the liquid crystal layer LC, light traveling toward the transparent layer 40 is reflected at the interface between the transparent substrate 30 and the transparent layer 40. Light L1 incident on the liquid crystal layer LC passes through pixels in the transparent state and is scattered by pixels in the scattering state. The display device DSP can be observed from both the main surface 10A side and the main surface 30B side. The display device DSP is a so-called transparent display, and the background of the display device DSP can be observed through the display device DSP whether observed from the main surface 10A side or the main surface 30B side.

[0065] According to this embodiment, it is possible to prevent the luminance of the display panel PNL from becoming non-uniform. When focusing on the luminance distribution of the light L1 from the light emitting element LD, the luminance tends to decrease in areas farther from the light emitting element LD. One of the causes of this decrease in luminance is the absorption and scattering of undesired light L1 by the liquid crystal layer LC, the signal line S, various insulating films, etc.

[0066] Furthermore, in a display device DSP having a shape other than rectangular, the distance from the side surface 31, where the light L1 enters the transparent substrate 30, to the side surface 32 opposite to the side surface 31 in the second direction Y is not constant. When light L1 of the same intensity is irradiated from each of the light emitting elements LD, the luminance of the display panel PNL tends to decrease in an area where the distance in the second direction Y from the side surface 31 to the side surface 32 is longer. Thus, in a display device DSP having a shape other than rectangular, there is a risk that the luminance of the display panel PNL will become non-uniform.

[0067] The area where the transparent layer 40 overlaps the pixel electrode PE corresponds to the area where light L1 from the light-emitting element LD is hardly incident on the display panel PNL, and the area where the transparent layer 40 does not overlap the pixel electrode PE (or the area between adjacent strip portions 41) corresponds to the area where light L1 from the light-emitting element LD is incident on the display panel PNL.

[0068] The overlapping area of ​​the transparent layer 40 per pixel electrode PE is larger in the region close to the light-emitting element LD than in the region farther from the light-emitting element LD. Therefore, in the region close to the light-emitting element LD, the incidence of light L1 on the display panel PNL is suppressed, and absorption and scattering of light L1 by the liquid crystal layer LC, the signal line S, various insulating films, etc. are suppressed. On the other hand, in the region farther from the light-emitting element LD, the incidence of light L1 on the display panel PNL is promoted. As described above, the light from the light-emitting element LD attenuates with increasing distance from the light-emitting element LD. The overlapping area between the pixel electrode PE1 and the transparent layer 40 shown in FIG. 4 is larger than the overlapping area between the pixel electrode PE2 and the transparent layer 40. Therefore, the area where light L1 can enter the pixel electrode PE1 is smaller than the area where light L1 can enter the pixel electrode PE2. Meanwhile, the intensity of light incident on the pixel electrode PE1 is stronger than the intensity of light incident on the pixel electrode PE2. This allows the brightness of the display panel PNL at the pixel electrodes PE1 and PE2 to be equalized.

[0069] 4, the overlapping area between the pixel electrode PE3 and the transparent layer 40 is equal to the overlapping area between the pixel electrode PE4 and the transparent layer 40. In addition, the intensity of the light L1 incident on the pixel electrode PE3 is equal to the intensity of the light L1 incident on the pixel electrode PE4. Therefore, the luminance of the display panel PNL at the pixel electrode PE3 and the pixel electrode PE4 can be equalized.

[0070] As described above, according to the present embodiment, even in a display device having a shape other than a rectangle, uneven brightness of the display panel PNL can be suppressed, and therefore, deterioration in the display quality of the image displayed on the display panel PNL can be suppressed.

[0071] 6 is a plan view showing a light guide element LG′ of a comparative example. The light guide element LG′ of the comparative example differs from the light guide element LG in that the band portions 41 do not have the same width in the first direction X at positions equidistant L from the straight portion S3 in the second direction Y.

[0072] In the comparative example shown in Fig. 6, each of the band portions 41 has an isosceles triangular shape extending in the second direction Y. In the comparative example shown in Fig. 6, with regard to the width WL of the band portion 41 along the first direction X at a position equidistant L in the second direction Y from the straight portion S3, the length of the band portion 41a extending in the second direction Y from near the center 33a of the straight portion S3 is the greatest, and the length of the band portion 41b extending in the second direction Y from near one end 33b of the straight portion S3 and the length of the band portion 41c extending in the second direction Y from near the other end 33c are the smallest. The width WL gradually decreases from the band portion 41a to the band portion 41b, and similarly, the width WL gradually decreases from the band portion 41a to the band portion 41c.

[0073] In the comparative example shown in FIG. 6 , among the pixel electrodes PE located at a distance L in the second direction Y from the straight portion S3, attention is focused on the pixel electrode PE3 located at the center in the first direction X and the pixel electrode PE4 located at an end in the first direction X. The area where the pixel electrode PE3 overlaps with the transparent layer 40 is larger than the area where the pixel electrode PE4 overlaps with the transparent layer 40. Therefore, the area of ​​the region where the light L1 can enter the pixel electrode PE3 is smaller than the area of ​​the region where the light L1 can enter the pixel electrode PE4. On the other hand, as described above, the intensity of the light L1 entering the pixel electrode PE3 is equal to the intensity of the light L1 entering the pixel electrode PE4. Therefore, the luminance of the pixel electrode PE3 is smaller than the luminance of the pixel electrode PE4, and the luminance of the display panel PNL at the pixel electrodes PE3 and PE4 cannot be equalized.

[0074] In the comparative example shown in FIG. 6, in a light-guiding element LG′ in which each of the band portions 41 does not have the same width WL along the first direction X at a position equidistant L from the straight portion S3 along the second direction Y, it is not possible to prevent the brightness of the display panel PNL from becoming uneven, and it is not possible to prevent a deterioration in the display quality of the image displayed on the display panel PNL.

[0075] Next, another configuration example of this embodiment will be described.

[0076] 7 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. 2. The example of the configuration shown in FIG. 7 differs from the example of the configuration shown in FIG. 2 in that the distance R2 along the second direction Y from the center 33a of the straight portion S3 to the curved portion C3 is different from the distance R1 from one end 33b of the straight portion S3 to the center 33a. The distance R1 from the center 33a of the straight portion S3 to one end 33b of the straight portion S3 is longer than the distance R2 along the second direction Y from the center 33a of the straight portion S3 to the curved portion C3. The transparent substrate 30 has a substantially semicircular shape in a plan view. The band portions 41 are arranged side by side in the first direction X.

[0077] With regard to the length of each of the band portions 41 along the second direction Y, the length of the band portion 41a extending in the second direction Y from near the center 33a of the straight portion S3 is the longest, while the lengths of the band portion 41b extending in the second direction Y from near one end 33b of the straight portion S3 and the band portion 41c extending in the second direction Y from near the other end 33c are the shortest. The length of the band portion 41 gradually decreases from the band portion 41a to the band portion 41b, and similarly, the length of the band portion 41 gradually decreases from the band portion 41a to the band portion 41c. Each of the band portions 41 has the same width WL along the first direction X at a position equidistant L from the straight portion S3 along the second direction Y. In this configuration example, the same effects as those in the configuration example shown in FIG. 2 can be obtained.

[0078] 8 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. 2. The example of the configuration shown in FIG. 8 differs from the example of the configuration shown in FIG. 2 in that the distance R2 along the second direction Y from the center 33a of the straight portion S3 to the curved portion C3 is different from the distance R1 from one end 33b of the straight portion S3 to the center 33a. The distance R1 from the center 33a of the straight portion S3 to one end 33b of the straight portion S3 is shorter than the distance R2 along the second direction Y from the center 33a of the straight portion S3 to the curved portion C3. The transparent substrate 30 has a substantially semicircular shape in a plan view. The band portions 41 are arranged side by side in the first direction X.

[0079] With regard to the length of each of the band portions 41 along the second direction Y, the length of the band portion 41a extending in the second direction Y from near the center 33a of the straight portion S3 is the longest, while the lengths of the band portion 41b extending in the second direction Y from near one end 33b of the straight portion S3 and the band portion 41c extending in the second direction Y from near the other end 33c are the shortest. The length of the band portion 41 gradually decreases from the band portion 41a to the band portion 41b, and similarly, the length of the band portion 41 gradually decreases from the band portion 41a to the band portion 41c. Each of the band portions 41 has the same width WL along the first direction X at a position equidistant L from the straight portion S3 along the second direction Y.

[0080] 9 is a plan view showing another example of the configuration of the light guide element LG shown in FIG. 2. The example of the configuration shown in FIG. 9 differs from the example of the configuration shown in FIG. 2 in that the transparent substrate 30 has a straight portion S3 extending along the first direction X, a straight portion S31 extending along the second direction Y, and a curved portion C3 facing the straight portion S3 in the second direction Y. The straight portion S3 has one end 33b connected to the curved portion C3 and the other end 33c connected to the straight portion S31. The transparent substrate 30 has a fan shape in a plan view. The band portions 41 are arranged side by side in the first direction X.

[0081] With regard to the length of each of the band portions 41 along the second direction Y, the length of the band portion 41b extending in the second direction Y from near one end 33b of the straight portion S3 is the smallest, and the length of the band portion 41c extending in the second direction Y from near the other end 33c of the straight portion S3 is the largest. The length of the band portion 41 gradually increases from the band portion 41b to the band portion 41c. Each of the band portions 41 has the same width WL along the first direction X at a position equidistant L along the second direction Y from the straight portion S3.

[0082] Fig. 10 is a plan view showing another configuration example of the light guide element LG shown in Fig. 2. The configuration example shown in Fig. 10 differs from the configuration example shown in Fig. 2 in that the transparent substrate 30 has a notch 33 that faces the straight line portion S3 in the second direction Y. In the example shown, the notch 33 is located between a curved line portion C31 connected to one end 33b of the straight line portion S3 and a curved line portion C32 connected to the other end 33c of the straight line portion S3. The notch 33 has a straight line portion S32 that extends along the first direction X. With respect to the length of each of the band portions 41 along the second direction Y, the length of the band portion 41 extending toward the straight portion S32 is approximately constant. The length of the band portion 41d adjacent to one end 33d of the straight portion S32 and extending toward the curved portion C31 and the length of the band portion 41e adjacent to the other end 33e of the straight portion S32 and extending toward the curved portion C32 are the longest. The length of the band portion 41b extending from near the one end 33b of the straight portion S3 and the length of the band portion 41c extending from near the other end 33c of the straight portion S3 are the shortest. The length of the band portion 41 gradually decreases from the band portion 41d toward the band portion 41b. The length of the band portion 41 gradually decreases from the band portion 41e toward the band portion 41c. Each of the band portions 41 has the same width WL along the first direction X at a position equidistant L from the straight portion S3 along the second direction Y.

[0083] In this configuration example, the same effects as those in the configuration example shown in FIG. 2 can be obtained.

[0084] As described above, according to this embodiment, it is possible to provide a display device capable of suppressing degradation in display quality.

[0085] In this embodiment, for example, transparent substrate 10 corresponds to the first transparent substrate, transparent substrate 20 corresponds to the second transparent substrate, transparent substrate 30 corresponds to the third transparent substrate, pixel electrode PE1 corresponds to the first pixel electrode, pixel electrode PE2 corresponds to the second pixel electrode, pixel electrode PE3 corresponds to the third pixel electrode, and pixel electrode PE4 corresponds to the fourth pixel electrode.

[0086] Although several 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 embodied 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 within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0087] DSP...Display device PNL...Display panel SE...Seal DA...Display area NDA...Non-display area PX...Pixel LC...liquid crystal layer 51...polymer 52...liquid crystal molecules LG: Light guide element LD: Light emitting element SW: Switching element PE: Pixel electrode CE: Common electrode G...Scanning line S...Signal line AD…Transparent adhesive layer RM: Reflective material 10...Transparent substrate 20...Transparent substrate 30...Transparent substrate 40...Transparent layer 41...Band part 411...First end part 412...Second end part 413...First edge 414...Second edge

Claims

1. a first substrate including a first transparent substrate and pixel electrodes arranged on the first transparent substrate for each of a plurality of pixels; a second substrate comprising a second transparent substrate; a liquid crystal layer disposed between the first substrate and the second substrate and including streaky polymer and liquid crystal molecules; A plurality of light-emitting elements arranged in a first direction; a third transparent substrate having a side surface facing the plurality of light-emitting elements; a transparent layer disposed between the second substrate and the third transparent substrate and having a refractive index lower than that of the third transparent substrate; Equipped with the third transparent substrate has, in a plan view, a straight portion located on a side facing the light emitting element and extending along the first direction, and a curved portion facing the straight portion and a second direction perpendicular to the first direction, the transparent layer includes a plurality of band portions arranged side by side in the first direction and extending in the second direction; Each of the plurality of strip portions has a first end portion facing the light emitting element and a second end portion opposite the first end portion, The width of the first end is greater than the width of the second end, Each of the plurality of band portions has the same width along the first direction at a position equidistant from the linear portion along the second direction. Display device.

2. each of the first transparent substrate and the second transparent substrate has a curved portion that overlaps a curved portion of the third transparent substrate in a plan view; The display device according to claim 1 .

3. the second transparent substrate has a linear portion that overlaps the linear portion of the third transparent substrate in a plan view, the first transparent substrate has an extension portion that extends in the second direction from the linear portion of the second transparent substrate in a plan view; The light-emitting element overlaps the extension portion in a plan view. The display device according to claim 2 .

4. The liquid crystal display device further includes a reflecting member disposed on a side surface along the curved portion of each of the first substrate, the second substrate, and the third transparent substrate. The display device according to claim 2 .

5. the first ends of the plurality of band portions are arranged on the same straight line along the first direction; The display device according to claim 1 .

6. a length from a center of the straight line portion to the curved line portion along the second direction is equal to a length from an end of the straight line portion to the center; The display device according to claim 1 .

7. The curved portion is formed in an arc shape. The display device according to claim 6.

8. a length from a center of the linear portion to the curved portion along the second direction is different from a length from an end of the linear portion to the center; The display device according to claim 1 .

9. the third transparent substrate has a notch facing the linear portion in the second direction; The display device according to claim 1 .

10. the first substrate further includes scanning lines, signal lines intersecting the scanning lines, and switching elements electrically connected to the scanning lines and the signal lines; Each of the plurality of strip portions overlaps the signal line. The display device according to claim 1 .

11. The pixel electrodes include a first pixel electrode and a second pixel electrode aligned in the second direction, the second pixel electrode is closer to the curved portion than the first pixel electrode; an area where the first pixel electrode overlaps the transparent layer is larger than an area where the second pixel electrode overlaps the transparent layer; The display device according to claim 1 .

12. the pixel electrodes include a third pixel electrode and a fourth pixel electrode that are arranged at equal distances from the linear portion along the second direction and are aligned in the first direction, the third pixel electrode is located at the center in the first direction, the fourth pixel electrode is closer to the curved portion than the third pixel electrode; an area where the third pixel electrode overlaps with the transparent layer is equal to an area where the fourth pixel electrode overlaps with the transparent layer; The display device according to claim 1 .

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