Display device

Abstract

To provide a display device capable of suppressing deterioration in display quality.SOLUTION: A light guide plate, a first transparent substrate, a second transparent substrate disposed between the light guide plate and the first transparent substrate, a liquid crystal layer disposed between the first transparent substrate and the second transparent substrate and including a stripe-shaped polymer and liquid crystal molecules, A first transparent layer having an opening opposed to the liquid crystal layer, and a protective layer disposed between the light guide and the first transparent substrate and overlapping the opening in planar view, wherein the first transparent layer has a refractive index smaller than those of the second transparent substrate and the protective layer, and the protective layer has a light scattering property higher than that of the second transparent substrate.SELECTED DRAWING: Figure 3

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. 2020-16684 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 comprises a light guide plate, a first transparent substrate, a second transparent substrate arranged between the light guide plate and the first transparent substrate, a liquid crystal layer arranged between the first transparent substrate and the second transparent substrate and containing streaky polymer and liquid crystal molecules, a first transparent layer arranged between the light guide plate and the first transparent substrate and having an opening facing the liquid crystal layer, and a protective layer arranged between the light guide plate and the first transparent substrate and overlapping the opening in a planar view, wherein the first transparent layer has a refractive index smaller than that of the second transparent substrate and the protective layer, and the protective layer has a light scattering property higher than that of the second transparent substrate. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a plan view showing an example of the configuration of a display device according to this embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the configuration of the display panel shown in FIG. [Figure 3] FIG. 3 is an exploded perspective view showing a main part of the display device shown in FIG. [Figure 4] FIG. 4 is a plan view showing an example of the configuration of the second substrate shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing an example of the configuration of the display device of this embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing another example of the configuration of the second substrate shown in FIG. [Figure 7] FIG. 7 is a plan view showing an example of the configuration of the second substrate 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 in the shape of flat plates parallel to the XY plane. The first substrate SUB1 and the second substrate SUB2 overlap each other in a planar view. The first substrate SUB1 and the second substrate SUB2 are bonded together with the seal SE.

[0011] The first substrate SUB1 has an edge E1 extending along the first direction X. The second substrate SUB2 has an edge E2 extending along the first direction X. The edge E2 does not overlap the edge E1 in a plan view. The first substrate SUB1 has an extending portion Ex extending from the edge E2 in the second direction Y in a plan view. In the example shown, the extending portion Ex corresponds to a region of the first substrate SUB1 that does not overlap with the second substrate SUB2.

[0012] The liquid crystal layer LC is held between the first substrate SUB1 and the second substrate SUB2 and sealed with a seal SE. In Fig. 1, the liquid crystal layer LC is indicated by dots and the seal SE is indicated by diagonal lines.

[0013] As schematically shown in an enlarged view in FIG. 1, the liquid crystal layer LC includes a polymer-dispersed liquid crystal including a polymer 31 and liquid crystal molecules 32. In one example, the polymer 31 is a liquid crystal polymer. The polymer 31 is formed in stripes extending along a first direction X. The liquid crystal molecules 32 are dispersed in gaps between the polymer 31 and are oriented with their major axes aligned along the first direction X. Each of the polymer 31 and the liquid crystal molecules 32 has optical anisotropy or refractive index anisotropy. The responsiveness of the polymer 31 to an electric field is lower than that of the liquid crystal molecules 32 to an electric field.

[0014] In one example, the alignment direction of the polymer 31 hardly changes regardless of the presence or absence of an electric field. On the other hand, the alignment direction of the liquid crystal molecules 32 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 31 and the liquid crystal molecules 32 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 31 and the liquid crystal molecules 32 intersect with each other, and light incident on the liquid crystal layer LC is scattered within the liquid crystal layer LC (scattered state).

[0015] The display panel PNL includes, in a plan view, a display section DA that displays an image in an area where the first substrate SUB1 and the second substrate SUB2 overlap, and a frame-shaped non-display section NDA that surrounds the display section DA. The seal SE is located in the non-display section NDA. The display section DA includes pixels PX arranged in a matrix in the first direction X and the second direction Y. The display section DA has edges E3 and E4 that extend along the first direction X. The edge E3 is located between the edge E2 and the edge E4 in the second direction Y.

[0016] 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 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 drives the liquid crystal layer LC (particularly, liquid crystal molecules 32) 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.

[0017] 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.

[0018] Fig. 2 is a cross-sectional view showing an example of the configuration of the display panel PNL 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.

[0019] The first substrate SUB1 includes a transparent substrate 10, insulating layers 11 and 12, a capacitance electrode 13, a switching element SW, a pixel electrode PE, and an alignment film AL1. The first substrate SUB1 further includes the scanning lines G and signal lines S shown in FIG. 1. The scanning lines G are disposed, for example, between the transparent substrate 10 and the insulating layer 11.

[0020] 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. The switching element SW is disposed on the main surface 10B, for example. The insulating layer 11 covers the switching element SW and the main surface 10B. The capacitive electrode 13 is disposed between the insulating layer 11 and the insulating layer 12.

[0021] The pixel electrode PE is disposed for each pixel PX between the insulating layer 12 and the alignment film AL1. The pixel electrode PE is electrically connected to the switching element SW through an opening OP1 in the capacitance electrode 13. The pixel electrode PE overlaps with the capacitance electrode 13 with the insulating layer 12 sandwiched therebetween, forming a capacitance CS for the pixel PX. The alignment film AL1 covers the pixel electrode PE and the insulating layer 12.

[0022] The second substrate SUB2 includes a transparent substrate 20, a light-shielding layer BM, a common electrode CE, a transparent layer 41, a protective layer 50, and an alignment film AL2. The transparent substrate 20 includes a main surface (lower surface) 20A and a main surface (upper surface) 20B opposite the main surface 20A. The main surfaces 20A and 20B are surfaces 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.

[0023] The light-shielding layer BM is disposed between the main surface 20A and the alignment film AL2. In the example shown in Fig. 2, the light-shielding layer BM is formed on the main surface 20A. The light-shielding layer BM is located above the switching elements SW and above the signal lines S and scanning lines G (not shown).

[0024] The common electrode CE is disposed between the principal surface 20A and the alignment film AL2. In the example shown in FIG. 2, the common electrode CE is disposed on the principal surface 20A. The common electrode CE covers the light-shielding layer BM. The common electrode CE is disposed across the plurality of pixels PX and faces each of the pixel electrodes PE in the third direction Z via the liquid crystal layer LC. The common electrode CE is electrically connected to the capacitance electrode 13 and has the same potential as the capacitance electrode 13.

[0025] The transparent layer 41 is disposed between the main surface 20A and the alignment film AL2. In the example shown in Fig. 2, the transparent layer 41 is disposed between the common electrode CE and the protective layer 50, and is formed on the surface of the common electrode CE that faces the liquid crystal layer LC. The transparent layer 41 is in contact with the common electrode CE and the protective layer 50. The transparent layer 41 overlaps the display section DA in a plan view.

[0026] In the example shown in FIG. 2, the transparent layer 41 includes a plurality of strip portions 41a. The strip portions 41a are arranged side by side in the first direction X, extend along the second direction Y, and are formed in a generally isosceles triangle shape. For example, the strip portions 41a are located above the switching elements SW in the third direction Z and overlap the switching elements in a planar view. The strip portions 41a are also located above the light-shielding layer BM and overlap the light-shielding layer BM in a planar view. Although not shown, the strip portions 41a may be located above the signal lines S in the third direction Z and overlap the signal lines S in a planar view. The shape of the strip portions 41a will be described later.

[0027] The transparent layer 41 has an opening OP2 between adjacent strip portions 41a. The opening OP2 faces the liquid crystal layer LC. In the example shown in Fig. 2, the common electrode CE is exposed from the transparent layer 41 at the opening OP2.

[0028] The protective layer 50 covers the transparent layer 41. The protective layer 50 is disposed between the transparent layer 41 and the alignment film AL2. The protective layer 50 is also disposed at the opening OP2 between the main surface 20A and the alignment film AL2. In the example shown in FIG. 2, the protective layer 50 is disposed between the common electrode CE and the alignment film AL2. The protective layer 50 overlaps the opening OP2 in a plan view. In the example shown in FIG. 2, the protective layer 50 is in contact with the transparent layer 41 and the alignment film AL2, and is in contact with the transparent layer 41, the alignment film AL2, and the common electrode CE at the opening OP2. The alignment film AL2 covers the protective layer 50. The liquid crystal layer LC is disposed between the first substrate SUB1 and the second substrate SUB2, and is in contact with the alignment films AL1 and AL2.

[0029] On the first substrate SUB1, the switching element SW, insulating layers 11 and 12, capacitive electrode 13, pixel electrode PE, and 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, common electrode CE, transparent layer 41, protective layer 50, and alignment film AL2 are located between the main surface 20A and the liquid crystal layer LC.

[0030] The transparent substrates 10 and 20 are insulating substrates such as glass substrates, plastic substrates, etc. The insulating layers 11 and 12 are inorganic insulating films such as silicon oxide, silicon nitride, and silicon oxynitride, or organic insulating films such as acrylic resin.

[0031] The capacitance electrode 13, pixel electrode PE, and common electrode CE are transparent electrodes made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The light-shielding layer BM may be a light-absorbing layer made of a light-absorbing material, or a light-reflecting layer made of a light-reflective material. The light-shielding layer BM may also be an insulating layer made of an inorganic or organic material, or a conductive layer made of a metal material.

[0032] The transparent layer 41 is an insulating layer formed of an organic material such as a siloxane-based resin or a fluorine-based resin. The protective layer 50 is a layer formed of a material having light scattering properties. The protective layer 50 is formed of an insulating material containing a filler having light scattering properties. The filler is, for example, an inorganic filler or a hollow filler. The filler is, for example, hollow silica. The insulating material is, for example, an inorganic insulating material or an organic insulating material.

[0033] 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.

[0034] The transparent substrate 10 has a thickness T1, and the transparent substrate 20 has a thickness T2. In the illustrated example, the thickness T1 is equal to the thickness T2. The transparent layer 41 has a thickness T41. The thickness T41 is, for example, 1 μm or more.

[0035] The transparent substrate 10 has a refractive index n10, the transparent substrate 20 has a refractive index n20, and the protective layer 50 has a refractive index n50. The transparent layer 41 has a refractive index n41 that is smaller than the refractive indices n10, n20, and n50. For example, the refractive indices n10 and n20 are approximately 1.4 to 2.5, the refractive index n50 is approximately 1.5, and the refractive index n41 is 1.0 or greater and 1.41 or less.

[0036] The protective layer 50 has a higher light scattering property than the transparent substrate 20. For example, the light scattering property of the protective layer 50 is equivalent to the light scattering property of the transparent layer 41.

[0037] Fig. 3 is an exploded perspective view showing the main part of the display device DSP shown in Fig. 1. In Fig. 3, the transparent layer 41 is shown in a transparent manner by a dotted line.

[0038] 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.

[0039] The light emitting module LM includes a plurality of light emitting elements LD and a wiring board F. 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 the wiring board F. In the example shown in FIG. 3, 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.

[0040] The light guide element LG includes a transparent substrate 30. The transparent substrate 30 includes 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 that are approximately parallel to the XY plane. The main surface 30A faces the main surface 20B of the transparent substrate 20.

[0041] The transparent substrate 30 has a side surface 30C. The side surface 30C is a plane that is approximately parallel to the XZ plane defined by the first direction X and the third direction Z. The side surface 30C is located on the side facing the light-emitting element LD in a plan view. The side surface 30C faces the light-emitting element LD in the second direction Y.

[0042] The transparent substrate 30 is bonded to the transparent substrate 20. In the example shown in Fig. 3, the side surface 30C is located on the edge E2 of the transparent substrate 20, but it may be located on the extension Ex or may be located further outward than the edge E1.

[0043] The transparent substrate 30 is an insulating substrate. 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.

[0044] The transparent substrate 30 has a thickness T3. In one example, the thickness T3 is thicker than the thickness T1 of the transparent substrate 10 and the thickness T2 of the transparent substrate 20. Note that the thickness T3 may be equal to the thicknesses T1 and T2. In one example, the thickness T3 is 200 μm to 2000 μm.

[0045] The transparent substrate 30 has a refractive index n30. The refractive index n30 is equivalent to the refractive indices n10 and n20 of the transparent substrates 10 and 20, and is higher than the refractive index n41 of the transparent layer 41. Here, "equivalent" does not necessarily mean that the difference in refractive index is zero, but also includes a case where the difference in refractive index is 0.03 or less.

[0046] Fig. 4 is a plan view showing an example of the configuration of the second substrate SUB2 shown in Fig. 2. The protective layer 50 is omitted in Fig. 4. In Fig. 4, the band portion 41a is schematically shown with its width in the first direction X enlarged. In Fig. 4, the area overlapping with the display portion DA is shown by a dashed line.

[0047] 4, the transparent layer 41 has a plurality of strip portions 41a aligned in the first direction X. Each strip portion 41a 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 first end portions 411 are arranged on the same straight line along the first direction X.

[0048] 4, the first end 411 overlaps the edge E3 of the display unit DA in a plan view, and the second end 412 overlaps the edge E4 of the display unit DA in a plan view, but this is not limiting. From the perspective of suppressing light leakage between the edge E2 of the second substrate and the display unit DA, it is desirable that the first end 411 be close to the edge E2 beyond the display unit DA.

[0049] 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 term "width" refers 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 L of one light-emitting element LD, and one light-emitting element LD is arranged across multiple strip portions 41a aligned in the first direction X. 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). The first width W1 and the second width W2 are approximately the same for all strip portions 41a.

[0050] 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. In the example shown in FIG. 4 , 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.

[0051] 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.

[0052] The strip portion 41a having such a shape has a width that gradually decreases at a constant rate or at an arbitrary rate from the first end portion 411 to the second end portion 412. The pitch between adjacent strip portions 41a 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).

[0053] The common electrode CE is exposed between adjacent strip portions 41a, i.e., at the opening OP2. Although not shown, the protective layer 50 overlaps the strip portions 41a and the opening OP2. The pixel electrode PE overlaps two adjacent strip portions 41a in plan view.

[0054] 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 41 is larger than the area where the pixel electrode PE2 overlaps with the transparent layer 41. In other words, the area where the main surface 20A and the pixel electrode PE1 overlap without the transparent layer 41 is smaller than the area where the main surface 20A and the pixel electrode PE2 overlap without the transparent layer 41. In this way, the overlapping area between the pixel electrode PE and the transparent layer 41 is larger in the region close to the light-emitting element LD than in the region farther from the light-emitting element LD.

[0055] The shape of the transparent layer 41 is not limited to the above-described shape, but may be any shape that allows the overlapping area between the pixel electrode PE and the transparent layer 41 to be larger in a region close to the light-emitting element LD than in a region away from the light-emitting element LD.

[0056] As will be described later, the area overlapping the transparent layer 41 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 20A without going through the transparent layer 41 corresponds to an area where light from the light-emitting element LD can enter the display panel PNL.

[0057] 5 is a cross-sectional view showing an example of the configuration of the display device DSP of this embodiment. Note that only the main parts of the display panel PNL are shown. With reference to FIG. 5, the light emitted from the light emitting element LD will be described.

[0058] The light-emitting element LD emits light L1 toward the side surface 30C of the transparent substrate 30. Because an air layer exists between the light-emitting element LD and the side surface 30C, the light L1 emitted from the light-emitting element LD is refracted at the side surface 30C and enters the transparent substrates 20 and 30. 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. Furthermore, of the light L1 incident on the transparent substrate 20, a portion of the light traveling toward the transparent layer 41 is reflected at the interface between the common electrode CE and the transparent layer 41 and does not reach the alignment film AL2, the liquid crystal layer LC, or the first substrate SUB1. On the other hand, of the light traveling from the transparent substrate 20 toward the transparent layer 41, the light with an incident angle smaller than the critical angle passes through the transparent layer 41 and reaches the alignment film AL2, the liquid crystal layer LC, and the first substrate SUB1, as indicated by the dashed lines.

[0059] In this way, most of the light L1 is repeatedly reflected near the side surface 30C (or in the region where the transparent layer 41 is present) and travels inside the transparent substrates 20 and 30. Of the traveling light L1, the light traveling toward the region where the transparent layer 41 is not present passes through the protective layer 50 and enters the liquid crystal layer LC and the first substrate SUB1.

[0060] The liquid crystal layer LC of a pixel to which a voltage is applied scatters the light L1. The liquid crystal layer LC of a pixel to which no voltage is applied transmits the light L1. The display device DSP can be observed from the main surface 10A side and also from the main surface 30B side. The background of the display device DSP can be observed through the display device DSP whether the display device DSP is observed from the main surface 10A side or the main surface 30B side.

[0061] According to this embodiment, it is possible to suppress a decrease in the display quality of the display panel PNL. 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 of unwanted light L1 by the liquid crystal layer LC, the switching element SW, the signal line S, various insulating films, etc.

[0062] The area where the transparent layer 41 overlaps the pixel electrode PE corresponds to the area where light from the light-emitting element LD hardly enters the alignment film AL1 and the liquid crystal layer LC, and the area where the transparent layer 41 does not overlap the pixel electrode PE (or the area between adjacent transparent layers 41) corresponds to the area where light from the light-emitting element LD enters the liquid crystal layer LC through the protective layer 50.

[0063] In the region close to the light-emitting element LD, the overlapping area of ​​the transparent layer 41 per pixel electrode PE is larger 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 of light L1 by the liquid crystal layer LC, switching element SW, signal line S, various insulating films, etc. is 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 41 shown in FIG. 4 is larger than the overlapping area between the pixel electrode PE2 and the transparent layer 41. 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. On the other hand, 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.

[0064] In such a display device DSP, undesired light scattering may occur in the transparent layer 41. This may make the boundary between the area overlapping with the transparent layer 41 and the area not overlapping with the transparent layer 41 more visible in plan view, which may impair the display quality of the display panel PNL.

[0065] The transparent layer 41 has an opening OP2. The opening OP2 corresponds to a region where the transparent layer 41 is not provided. The protective layer 50 is provided so as to overlap the opening OP2. The protective layer 50 has light scattering properties. This makes it possible to prevent a difference in the light scattering properties of the display panel PNL between the region overlapping with the transparent layer 41 and the region overlapping with the opening OP2 (i.e., the region not overlapping with the transparent layer 41). This makes it possible to prevent the boundary between the region overlapping with the transparent layer 41 and the region not overlapping with the transparent layer 41 from becoming easily visible in the display panel PNL.

[0066] In this way, according to this embodiment, it is possible to suppress a decrease in the display quality of the image displayed on the display panel PNL.

[0067] Next, another configuration example of this embodiment will be described. Fig. 6 is a cross-sectional view showing another example of the configuration of the second substrate SUB2 shown in Fig. 2. The description above will be used to omit a description of the same configuration as the above example. The example shown in Fig. 6 differs from the example shown in Fig. 2 in that the second substrate SUB2 further includes a transparent layer 42.

[0068] The transparent layer 41 is formed on the surface of the common electrode CE facing the liquid crystal layer LC. The transparent layer 41 is in contact with the common electrode CE, the protective layer 50, and the transparent layer 42. The transparent layer 41 has a plurality of strip portions 41a aligned in the first direction X. The transparent layer 41 has openings OP2 between adjacent strip portions 41a that face the liquid crystal layer LC.

[0069] The transparent layer 42 is disposed between the transparent substrate 20 and the protective layer 50. In the example shown in Fig. 6, the transparent layer 42 is disposed between the common electrode CE and the protective layer 50, and is formed on the surface of the common electrode CE that faces the liquid crystal layer LC. Although not shown, the transparent layer 42 may also be formed on the main surface 20A.

[0070] The transparent layer 42 is disposed in the opening OP2 in plan view. From another perspective, the transparent layer 42 has a plurality of openings OP3 facing the liquid crystal layer LC, and the strip portion 41a is disposed in each of the plurality of openings OP3. Each of the plurality of openings OP3 is disposed side by side in the first direction X and extends in the second direction Y. The openings OP3 have the same planar shape as the strip portions 41a.

[0071] The transparent layer 42 is in contact with the common electrode CE, the transparent layer 41, and the protective layer 50. The transparent layers 41 and 42 are arranged alternately in the first direction X.

[0072] The protective layer 50 is disposed between the transparent layer 41 and the alignment film AL2, and between the transparent layer 42 and the alignment film AL2. The protective layer 50 covers the transparent layer 41 and the transparent layer 42. In the example shown in Fig. 6, the protective layer 50 contacts the transparent layer 41, the transparent layer 42, and the alignment film AL2. The protective layer 50 overlaps the opening OP2 in a plan view.

[0073] The transparent layer 42 is formed of a material different from that of the protective layer 50. The transparent layer 42 is an insulating layer formed of, for example, an organic material such as an acrylic resin, an inorganic material such as silicon dioxide, or glass. When the transparent layer 42 is formed on the main surface 20A, the transparent layer 42 and the transparent substrate 20 may be integrally formed of the same material.

[0074] The transparent layer 42 has a thickness T42. The thickness T42 is, for example, 1 μm or more. In the example shown in FIG.

[0075] The transparent layer 42 has a refractive index n42. The refractive index n42 is equivalent to the refractive index n50 of the protective layer 50 and is higher than the refractive index n41 of the transparent layer 41. 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.

[0076] 7 is a plan view showing an example of the configuration of the second substrate SUB2 shown in FIG. 6. The description above will be used to omit explanations of the same configuration as the above example. In FIG. 7, the protective layer 50 is omitted. In addition, in FIG. 7, the width of the band portion 41a in the first direction X is enlarged and schematically shown. In addition, in FIG. 7, the area overlapping with the display portion DA is indicated by a dashed line.

[0077] The transparent layer 41 has a plurality of band portions 41a aligned in the first direction X. The transparent layer 42 is formed between adjacent band portions 41a, i.e., in the openings OP2, and overlaps the openings OP2 in plan view. From another perspective, the transparent layer 42 has a plurality of openings OP3. In the example shown in FIG. 7, each of the plurality of openings OP3 is aligned in the first direction X and extends in the second direction Y. The band portion 41a is formed in each of the plurality of openings OP3.

[0078] The opening OP3 has the same planar shape as the transparent layer 41. In the example shown in FIG. 7, the opening OP3 has a first end 421 facing the light-emitting element LD, a second end 422 opposite the first end 421, a first edge 423, and a second edge 424. The opening OP3 has a width that gradually decreases at a constant rate or an arbitrary rate from the first end 421 to the second end 422. In the example shown in FIG. 7, the transparent layer 42 is also provided on the peripheral edge of the second substrate SUB2 so as to surround the multiple band portions 41a.

[0079] In plan view, the pixel electrode PE overlaps two adjacent transparent layers 41. The pixel electrode PE overlaps the transparent layer 42 between the transparent layers 41, that is, in the opening OP2.

[0080] The display device DSP scatters light L1 incident on the liquid crystal layer LC by applying an electric field to the liquid crystal layer LC to change the alignment direction of the liquid crystal molecules. If the thickness of the liquid crystal layer LC is non-uniform, the electric field strength applied to the liquid crystal layer LC will be non-uniform, which may impair the display quality of the display panel PNL.

[0081] The transparent layer 41 has a certain thickness or more to reflect the light L1. When the transparent layer 41 is provided inside the display panel PNL, the thickness of the transparent layer 41 may affect the thickness of the liquid crystal layer LC, which may result in non-uniformity.

[0082] The transparent layer 42 is provided between two adjacent transparent layers 41, i.e., in the opening OP2. This reduces the difference in thickness between the region where the transparent layer 41 is provided (the region where the incidence of the light L1 on the display panel PNL is suppressed) and the region where the transparent layer 41 is not provided (the region where the light L1 is incident on the display panel PNL), and makes it possible to flatten the alignment film AL2 provided on the protective layer 50. This makes it possible to uniformize the distance between the alignment film AL1 and the alignment film AL2, i.e., the thickness of the liquid crystal layer LC.

[0083] In this configuration example, the same effects as those of the configuration example shown in Fig. 2 can be obtained. In addition, since it is possible to prevent the thickness of the liquid crystal layer LC from becoming non-uniform, it is possible to further prevent a decrease in the display quality of the image displayed on the display panel PNL.

[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, the transparent substrate 10 corresponds to the first transparent substrate, the transparent substrate 20 corresponds to the second transparent substrate, the transparent substrate 30 corresponds to the light guide plate, the transparent layer 41 corresponds to the first transparent layer, the transparent layer 42 corresponds to the second transparent layer, the pixel electrode PE1 corresponds to the first pixel electrode, and the pixel electrode PE2 corresponds to the second 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 31...polymer 32...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 10, 20, 30...Transparent substrate 41, 42...Transparent layer 50...Protective layer

Claims

1. A light guide plate; a first transparent substrate; a second transparent substrate disposed between the light guide plate and the first transparent substrate; a liquid crystal layer disposed between the first transparent substrate and the second transparent substrate, the liquid crystal layer including streaky polymer and liquid crystal molecules; a first transparent layer disposed between the light guide plate and the first transparent substrate, the first transparent layer having an opening facing the liquid crystal layer; a protective layer disposed between the light guide plate and the first transparent substrate and overlapping the opening in a plan view; the first transparent layer has a refractive index smaller than that of the second transparent substrate and the protective layer; The display device, wherein the protective layer has a higher light scattering property than the second transparent substrate.

2. the protective layer is disposed between the second transparent substrate and the liquid crystal layer; The display device according to claim 1 , wherein the first transparent layer is disposed between the second transparent substrate and the protective layer.

3. further comprising a common electrode disposed between the second transparent substrate and the first transparent layer; The display device according to claim 2 , wherein the protective layer is in contact with the common electrode at the opening.

4. Further, a second transparent layer is provided in the opening, The display device according to claim 1 , wherein the refractive index of the second transparent layer is equal to the refractive index of the protective layer.

5. The display device according to claim 4 , wherein the second transparent layer is formed of a material different from that of the protective layer.

6. the protective layer is disposed between the second transparent substrate and the liquid crystal layer; The display device according to claim 4 , wherein the first transparent layer and the second transparent layer are disposed between the second transparent substrate and the protective layer.

7. a common electrode provided between the second transparent substrate and the second transparent layer; The display device according to claim 6 , wherein the second transparent layer is in contact with the first transparent layer, the protective layer, and the common electrode.

8. The display device according to claim 1 , wherein the protective layer contains a filler having light scattering properties.

9. The display device according to claim 8 , wherein the filler is made of an inorganic material.

10. The display device according to claim 9 , wherein the filler is formed of hollow silica.

11. The liquid crystal display device further includes a plurality of light-emitting elements arranged in a first direction, and first and second pixel electrodes arranged in a second direction perpendicular to the first direction, the first pixel electrode is located between the second pixel electrode and the plurality of light-emitting elements; The display device according to claim 1 , wherein an area of ​​the first pixel electrode overlapping the first transparent layer in a plan view is larger than an area of ​​the second pixel electrode overlapping the first transparent layer.

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