Display device

Abstract

To provide a display device that can suppress a falling in display quality without using a low refractive index material.SOLUTION: According to one embodiment, a display device comprises: a display panel; a plurality of light emitting elements; a third transparent substrate; and a structure. The display panel includes: a first transparent substrate; a second transparent substrate; a polymer dispersion type crystal liquid layer that is positioned between the first transparent substrate and the second transparent substrate; a first pixel electrode and second pixel electrode; and a common electrode. The plurality of light emitting elements lines in a first direction. The third transparent substrate has a lateral face facing the plurality of light emitting elements, and faces the second transparent substrate. The structure contacts with the second transparent substrate and the third transparent substrate. The second pixel electrode is separated from the plurality of light emitting elements further than the first pixel electrode, and the structure includes: a plurality of first structures overlapping the first pixel electrode; and a second structure that has a plurality of openings overlapping the second pixel electrode.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Embodiments of the present invention relate to a display device.

Background Art

[0002] In recent years, various display devices using polymer dispersed liquid crystal (hereinafter referred to as PDLC) that can be switched between a scattered state and a transparent state have been proposed. In one example, a display device using PDLC includes a display panel, a transparent substrate adhered to the display panel, a light source disposed on one end side of the transparent substrate, and a low refractive index layer located between the display panel and the transparent substrate and having a refractive index smaller than that of the transparent substrate. The low refractive index layer has, for example, an opening that becomes smaller as it moves away from the light source.

[0003] For example, the siloxane-based resin used as the material of the low refractive index layer is likely to gasify and may have various adverse effects during the production process. In addition, fluorine compounds used as other materials for the low refractive index layer are subject to increasing global regulations.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a display device capable of suppressing a decrease in display quality without using a low refractive index material.

Means for Solving the Problem

[0006] According to one embodiment, a display device includes a display panel, a plurality of light-emitting elements, a third transparent substrate, and a structure. The display panel includes a first transparent substrate, a second transparent substrate facing the first transparent substrate, a polymer-dispersed liquid crystal layer positioned between the first transparent substrate and the second transparent substrate, a first pixel electrode and a second pixel electrode positioned between the first transparent substrate and the liquid crystal layer, and a common electrode positioned between the second transparent substrate and the liquid crystal layer and facing the first pixel electrode and the second pixel electrode. The plurality of light-emitting elements are arranged in a first direction. The third transparent substrate has a side surface facing the plurality of light-emitting elements and faces the second transparent substrate. The structure is in contact with the second transparent substrate and the third transparent substrate and guides light emitted from the plurality of light-emitting elements from the third transparent substrate to the liquid crystal layer. The second pixel electrode is spaced farther from the plurality of light-emitting elements than the first pixel electrode, and the structure includes a plurality of first structures overlapping the first pixel electrode and a second structure having a plurality of openings overlapping the second pixel electrode. The plurality of first structures and the plurality of openings are each arranged at a first pitch in the first direction and are each arranged at a second pitch equal to the first pitch in a second direction orthogonal to the first direction. The area where the first structure overlaps the first pixel electrode is smaller than the area where the second structure overlaps the second pixel electrode.

Brief Description of the Drawings

[0007]

Figure 1

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Embodiments for Carrying Out the Invention

[0008] Some embodiments will be described with reference to the drawings. The disclosure is merely an example, and for those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the invention, they are naturally included in the scope of the present invention. Also, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but it is merely an example and does not limit the interpretation of the present invention. Further, in this specification and each figure, components having the same or similar functions as those described above with respect to the previously presented figures are given the same reference numerals, and detailed descriptions that are redundant may be omitted as appropriate.

[0009] In the drawings, for the sake of easy understanding if necessary, the X-axis, Y-axis, and Z-axis that are orthogonal to each other are described. The direction along the X-axis is referred to as the first direction X, the direction along the Y-axis is referred to as the second direction Y, and the direction along the Z-axis is referred to as the third direction Z. Looking at various elements parallel to the third direction Z is called a plan view. The first direction X and the second direction Y are directions parallel to the main surface of the substrate constituting the display device, and the third direction Z corresponds to the thickness direction of the display device.

[0010] In the present embodiment, as an example of the display device, a highly light-transmissive liquid crystal display device (so-called transparent display device) applying polymer-dispersed liquid crystal is disclosed. However, the configuration disclosed in the present embodiment, particularly the configuration regarding the mounting area and various elements arranged in the vicinity thereof, is applicable to other types of display devices as well.

[0011] [First Embodiment] FIG. 1 is a diagram showing a configuration example of a display device DSP according to the first embodiment. The display device DSP includes a display panel PNL, a light source unit LU, and a light guide LG. In FIG. 1, a broken line is attached to the light source unit LU and the light guide LG to omit a part thereof.

[0012] The display panel PNL includes a first substrate SUB1 and a second substrate SUB2 stacked in the third direction Z. In FIG. 1, the shapes of the first substrate SUB1 and the second substrate SUB2 in plan view both have a rectangular shape with a long side parallel to the first direction X. However, the shapes of the first substrate SUB1 and the second substrate SUB2 are not limited to this example, and may be, for example, a rectangular shape with a long side parallel to the second direction Y, a circular shape, an elliptical shape, or the like.

[0013] The width of the first substrate SUB1 in the second direction Y is larger than the width of the second substrate SUB2 in the second direction Y. Thereby, the first substrate SUB1 has a mounting area MA that does not overlap with the second substrate SUB2. An integrated circuit or a flexible circuit board (not shown) is mounted in the mounting area MA.

[0014] The display panel PNL has a display area DA for displaying an image and a frame-shaped peripheral area SA surrounding the display area DA. Both the display area DA and the peripheral area SA are formed in a portion where the first substrate SUB1 and the second substrate SUB2 overlap. The display area DA includes a plurality of pixels PX arranged in a matrix in the first direction X and the second direction Y.

[0015] The display panel PNL further includes a liquid crystal layer LC sealed between the first substrate SUB1 and the second substrate SUB2. As schematically shown in an enlarged view below FIG. 1, the liquid crystal layer LC is composed of a polymer dispersed liquid crystal containing a polymer 31 and liquid crystal molecules 32. In one example, the polymer 31 is a liquid crystalline polymer. The polymer 31 is formed in a streak shape extending along the first direction X and arranged side by side in the second direction Y. The liquid crystal molecules 32 are dispersed in the gaps of the polymer 31 and are oriented such that their major axes are along the first direction X.

[0016] 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. 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 according to the voltage applied to the liquid crystal layer LC.

[0017] In a state where 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 the light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC with almost no scattering (transparent state).

[0018] In a state where a voltage is applied to the liquid crystal layer LC, the optical axes of the polymer 31 and the liquid crystal molecules 32 cross each other, and the light incident on the liquid crystal layer LC is scattered within the liquid crystal layer LC (scattering state).

[0019] As shown enlarged above FIG. 1, a plurality of scanning lines G and a plurality of signal lines S are arranged in the display area DA. The plurality of scanning lines G extend in the first direction X and are arranged side by side in the second direction Y. The plurality of signal lines S extend in the second direction Y and are arranged side by side in the first direction X. The plurality of signal lines S intersect the plurality of scanning lines G.

[0020] Each pixel PX includes a switching element SW, a pixel electrode PE, a common electrode CE, and a capacitor CS. The switching element SW is constituted by, for example, a thin film transistor (TFT) and is electrically connected to the scanning line G and the signal line S. The pixel electrode PE is electrically connected to the switching element SW.

[0021] The liquid crystal layer LC (particularly, liquid crystal molecules 32) is driven by an electric field generated between the pixel electrode PE and the common electrode CE. The capacitor 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.

[0022] The light source unit LU and the light guide LG are arranged along the mounting area MA. The light source unit LU includes a plurality of light emitting elements LS arranged side by side in the first direction X. Each light emitting element LS irradiates the light guide LG with light. As the light guide LG, for example, a lens such as a prism lens can be used.

[0023] For example, the plurality of light emitting elements LS include a light emitting element that emits red light, a light emitting element that emits green light, and a light emitting element that emits blue light. These light emitting elements may be arranged side by side in the first direction X or may be stacked in the third direction Z. As the light emitting element LS, an LED (Light Emitting Diode) can be used.

[0024] FIG. 2 is a cross-sectional view showing a configuration example of the display panel PNL shown in FIG. 1. The first substrate SUB1 includes a first transparent substrate 10, insulating films 11 and 12, a capacitive electrode 13, a switching element SW, a pixel electrode PE, and an alignment film AL1. Although not shown, the first substrate SUB1 further includes the scanning line G and the signal line S shown in FIG. 1. The switching element SW is disposed on the upper surface of the first transparent substrate 10. The insulating film 11 covers the switching element SW. The capacitive electrode 13 is located between the insulating films 11 and 12. In the illustrated example, the insulating film 11 and the capacitive electrode 13 are disposed over the entire surface of each pixel PX, but the present invention is not limited to this example. The insulating film 11 may be disposed so as to cover at least the switching element SW, the scanning line G, and the signal line S. The capacitive electrode 13 may be formed in a lattice pattern along the scanning line G and the signal line S. The pixel electrode PE is disposed for each pixel PX on the insulating film 12. The pixel electrode PE is electrically connected to the switching element SW through the opening OP of the capacitive electrode 13. The pixel electrode PE overlaps the capacitive electrode 13 with the insulating film 12 interposed therebetween, and forms the capacitance CS of the pixel PX. The alignment film AL1 covers the pixel electrode PE.

[0025] The second substrate SUB2 includes a second transparent substrate 20, a light-shielding layer BM, a common electrode CE, and an alignment film AL2. The second transparent substrate 20 faces the first transparent substrate 10 in the third direction Z. The light-shielding layer BM and the common electrode CE are disposed on the lower surface of the second transparent substrate 20. The light-shielding layer BM is located, for example, directly above the switching element SW and directly above the scanning line G and the signal line S (not shown). The common electrode CE faces the pixel electrode PE with the liquid crystal layer LC interposed therebetween in the third direction Z. The common electrode CE is disposed across a plurality of pixels PX and directly covers the light-shielding layer BM. The common electrode CE is electrically connected to the capacitive electrode 13 and has the same potential as the capacitive electrode 13. The alignment film AL2 covers the common electrode CE.

[0026] The liquid crystal layer LC is positioned between the first transparent substrate 10 and the second transparent substrate 20 and is in contact with the alignment films AL1 and AL2. On the first substrate SUB1, the insulating film 11, the insulating film 12, the capacitive electrode 13, the switching element SW, the pixel electrode PE, the alignment film AL1, and the scanning line G and the signal line S shown in FIG. 1 are positioned between the first transparent substrate 10 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 positioned between the second transparent substrate 20 and the liquid crystal layer LC.

[0027] The first transparent substrate 10 and the second transparent substrate 20 are insulating substrates such as glass substrates and plastic substrates. The insulating film 11 is formed of a transparent insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or acrylic resin. In one example, the insulating film 11 includes an inorganic insulating film and an organic insulating film. The insulating film 12 is an inorganic insulating film such as silicon nitride. The capacitive electrode 13, 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 is, for example, a conductive layer having a lower resistance than the common electrode CE. In one example, the light-shielding layer BM is formed of an opaque metal material such as molybdenum, aluminum, tungsten, titanium, or silver. The alignment films AL1 and AL2 are horizontal alignment films having an alignment regulating force substantially parallel to the X-Y plane. In one example, the alignment films AL1 and AL2 are alignment-processed along the first direction X. Note that the alignment process may be a rubbing process or an optical alignment process.

[0028] FIG. 3 is a schematic cross-sectional view of the display device DSP along the line A-A' shown in FIG. 1. In FIG. 3, the structure of the display panel PNL and the like is schematically shown, and elements such as the scanning line G, the signal line S, and the switching element SW are omitted.

[0029] The display panel PNL further includes a seal SE that bonds the first substrate SUB1 and the second substrate SUB2. The seal SE surrounds the display area DA in a plan view. The liquid crystal layer LC is sealed in a space surrounded by the seal SE.

[0030] The display device DSP further includes a third transparent substrate 30, a structure 40, and an adhesive AD.

[0031] The third transparent substrate 30 faces the second transparent substrate 20 in the third direction Z. The third transparent substrate 30 has a side surface 30S that faces a plurality of light-emitting elements LS with the light guide LG sandwiched therebetween in the second direction Y. In the example of FIG. 3, the side surface 30S is a plane parallel to the X-Z plane. The side surface 30S overlaps the side surface 20S of the second substrate SUB2 in the third direction Z.

[0032] In one example, the third transparent substrate 30 is a cover glass formed of glass. As another example, the third transparent substrate 30 may be formed of plastic. The third transparent substrate 30 is sufficiently thicker than the first substrate SUB1 and the second substrate SUB2. In one example, the third transparent substrate 30 has a thickness that is twice or more that of the first substrate SUB1 and the second substrate SUB2.

[0033] The structure 40 is located between the second transparent substrate 20 and the third transparent substrate 30 in the third direction Z and is in contact with the second transparent substrate 20 and the third transparent substrate 30. In the example of FIG. 3, the structure 40 adheres the upper surface 20U of the second transparent substrate 20 and the lower surface 30L of the third transparent substrate 30. When the structure 40 has almost no adhesive force, the structure 40 may be adhered to the second transparent substrate 20 and the third transparent substrate 30 by a transparent adhesive having a refractive index substantially equal to that of the second transparent substrate 20 and the third transparent substrate 30, for example.

[0034] The structure 40 includes a plurality of first structures 41 and a second structure 42. The plurality of first structures 41 are located closer to the light-emitting elements LS than the second structure 42 in the second direction Y. That is, the second structure 42 is spaced farther from the light-emitting elements LS than the plurality of first structures 41.

[0035] Details will be described later, but the plurality of first structures 41 are formed, for example, in a dot shape arranged at a predetermined pitch in a plan view. Each of the first structures 41 is arranged so as not to overlap with each other in a plan view. Each of the first structures 41 is surrounded by a low refractive index layer AR having a lower refractive index than the first structure 41. The low refractive index layer AR is not a layer formed of a low refractive index material such as a siloxane resin or a fluorine compound, but is, for example, an air layer, or may be a void in a vacuum state. Thus, in this specification, the low refractive index layer AR is not a solid layer formed using a low refractive index material, but is a gas layer or void such as air or an inert gas.

[0036] The second structure 42 has a plurality of openings AP. Details will be described later, but the plurality of openings AP are formed, for example, in a dot shape arranged at a predetermined pitch in a plan view. Each of the openings AP is arranged so as not to overlap with each other in a plan view. Each of the openings AP is filled with a medium (gas) having a lower refractive index than the second structure 42. For example, each of the openings AP is filled with air, or may be a void in a vacuum state.

[0037] In one example, the structure 40 is formed of a material such as an acrylic resin or an epoxy resin having adhesiveness. It is desirable that the refractive index of the structure 40 is equivalent to the refractive index of each of the second transparent substrate 20 and the third transparent substrate 30.

[0038] The adhesive AD adheres the upper surface 20U of the second transparent substrate 20 and the lower surface 30L of the third transparent substrate 30. The adhesive AD overlaps the seal SE in the third direction Z. For the adhesive AD, for example, OCA (Optical Clear Adhesive) or the like can be used. In addition, when the structure 40 has adhesiveness, the adhesive AD may be formed of the same material as the structure 40. The refractive index of the adhesive AD may be equivalent to or different from the refractive index of each of the structure 40, the second transparent substrate 20, and the third transparent substrate 30.

[0039] In this embodiment, the refractive index of the structure 40 is equal to the refractive index of each of the second transparent substrate 20 and the third transparent substrate 30. Also, the refractive index of air is smaller than the refractive index of each of the third transparent substrate 30 and the structure 40. In such a configuration, the light emitted from the light-emitting element LS passes through the light guide LG and enters the third transparent substrate 30 from the side surface 30S. The light incident on the third transparent substrate 30 is totally reflected at the boundary between the upper surface 30U of the third transparent substrate 30 and air, the boundary between the lower surface 30L of the third transparent substrate 30 and the low refractive index layer AR, and the boundary between the lower surface 30L of the third transparent substrate 30 and the opening AP, and propagates through the third transparent substrate 30. Also, since the refractive index of the structure 40 is equal to the refractive index of each of the second transparent substrate 20 and the third transparent substrate 30, the light propagating through the third transparent substrate 30 is hardly reflected at the boundary between the lower surface 30L and the structure 40. That is, a part of the light propagating through the third transparent substrate 30 passes through the structure 40, the second transparent substrate 20, and the common electrode CE and is incident on the liquid crystal layer LC. Thus, the structure 40 has a function of guiding the light emitted from the plurality of light-emitting elements LS from the third transparent substrate 30 to the liquid crystal layer LC. In order for light not to be reflected at the boundary between the lower surface 30L and the structure 40 and at the boundary between the upper surface 20U and the structure 40, the refractive index difference between the structure 40 and the second transparent substrate 20 and the refractive index difference between the structure 40 and the third transparent substrate 30 are desirably 0.05 or less, respectively. Also, as described above, since the light-emitting element LS faces only the side surface 30S of the third transparent substrate 30 in the second direction Y, the light emitted from the light-emitting element LS hardly directly enters the adhesive AD and the display panel PNL.

[0040] In the example shown in FIG. 3, the light L1 propagating through the third transparent substrate 30 is reflected at the boundary between the lower surface 30L and the low refractive index layer AR. Thereafter, the light L1 is reflected at the boundary between the upper surface 30U and air and enters the display panel PNL through the first structure 41. Also, the light L2 propagating through the third transparent substrate 30 is reflected at the boundary between the lower surface 30L and the opening AP. Thereafter, the light L2 is reflected at the boundary between the upper surface 30U and air and enters the display panel PNL through the second structure 42.

[0041] FIG. 4 is a plan view showing an example of the first structure 41. The first structure 41 includes a first structure 41a and a first structure 41b that is farther from the light-emitting element LS than the first structure 41a in the second direction Y.

[0042] Each of the plurality of pixel electrodes PE is surrounded by two scanning lines G adjacent to each other in the second direction Y and two signal lines S adjacent to each other in the first direction X.

[0043] The plurality of first structures 41 overlap the pixel electrode PE in the third direction Z. In the example of FIG. 4, a part of the plurality of first structures 41 overlaps the plurality of scanning lines G and the plurality of signal lines S in the third direction Z. In the example of FIG. 4, each of the first structures 41 is arranged at equal intervals in the first direction X and the second direction Y.

[0044] In plan view, the total area of the first structure 41b overlapping one pixel electrode PE (hereinafter referred to as the total area) is larger than the total area of the first structure 41a overlapping one pixel electrode PE. That is, the total area of the first structure 41 overlapping one pixel electrode PE in plan view increases as it moves away from the light-emitting element LS in the second direction Y.

[0045] FIG. 5 is a diagram showing an example of the second structure 42 and the opening AP. The opening AP includes an opening APa and an opening APb that is farther from the light-emitting element LS than the opening APa in the second direction Y.

[0046] The plurality of openings AP overlap the pixel electrode PE in the third direction Z. In the example of FIG. 5, a part of the plurality of openings AP overlaps the plurality of scanning lines G and the plurality of signal lines S in the third direction Z. In the example of FIG. 5, each of the openings AP is arranged at equal intervals in the first direction X and the second direction Y.

[0047] In plan view, the total area of the openings APb overlapping one pixel electrode PE is smaller than the total area of the openings APa overlapping one pixel electrode PE. That is, in plan view, the total area of the openings AP overlapping one pixel electrode PE becomes smaller as it moves away from the light-emitting element LS in the second direction Y. In other words, the total area of the second structure 42 overlapping one pixel electrode PE becomes larger as it moves away from the light-emitting element LS in the second direction Y.

[0048] FIG. 6 is a plan view showing a configuration example of the structure 40 and the adhesive AD. Note that the illustration of the third transparent substrate 30 is omitted. In the example of FIG. 6, the adhesive AD is disposed in the peripheral region SA and surrounds the display region DA. Further, the adhesive AD surrounds the structure 40 (the first structure 41 and the second structure 42).

[0049] The structure 40 is disposed in the region surrounded by the adhesive AD. In the example of FIG. 6, the structure 40 overlaps the display region DA. However, the structure 40 may overlap the display region DA and the peripheral region SA.

[0050] FIG. 7 is a plan view showing another configuration example of the structure 40 and the adhesive AD.

[0051] The adhesive AD extends along the first direction X and is located between the plurality of light-emitting elements LS and the structure 40 in plan view. Specifically, the adhesive AD is located between the side surface 20S of the second substrate SUB2 and the first structure 41 in plan view. In the example of FIG. 7, the structure 40 overlaps the display region DA and the peripheral region SA, but may overlap only the display region DA.

[0052] As shown in FIGS. 4 and 5, the area of the structure 40 becomes smaller as it approaches the light-emitting element LS. That is, when the structure 40 has an adhesive force, the adhesive area between the structure 40 and the second transparent substrate 20 and the third transparent substrate 30 becomes smaller as it approaches the light-emitting element LS. Therefore, compared with a location far from the light-emitting element LS, the third transparent substrate 30 is more likely to be peeled off from the display panel PNL at a location close to the light-emitting element LS. On the other hand, in the present embodiment, by disposing the adhesive AD between the light-emitting element LS and the structure 40, the third transparent substrate 30 is less likely to be peeled off from the display panel PNL on the side close to the light-emitting element LS. Further, as shown in FIG. 6, by disposing the adhesive AD so as to surround the structure 40, the third transparent substrate 30 becomes even less likely to be peeled off from the display panel PNL.

[0053] FIG. 8 is a plan view showing an example of the relationship between the structure 40 and the pixel electrode PE. The pixel electrode PE includes pixel electrodes PE1 to PE4. In the example of FIG. 8, the pixel electrodes PE1 and PE2 are arranged along the second direction Y. The pixel electrodes PE3 and PE4 are arranged along the second direction Y. The pixel electrodes PE1 and PE3 are arranged along the first direction X. The pixel electrodes PE2 and PE4 are arranged along the first direction X. The pixel electrodes PE2 and PE4 (second pixel electrodes) are spaced farther from the light-emitting element LS than the pixel electrodes PE1 and PE3 (first pixel electrodes). The pixel electrodes PE1 and PE3 are arranged in pixels in a region extremely close to the light-emitting element LS, and the pixel electrodes PE2 and PE4 are arranged in pixels in a region extremely far from the light-emitting element LS. A large number of pixel electrodes are arranged between the pixel electrode PE1 and the pixel electrode PE2, and between the pixel electrode PE3 and the pixel electrode PE4.

[0054] The plurality of scanning lines G shown in FIG. 1 includes scanning lines G1 to G4. Also, the plurality of signal lines S shown in FIG. 1 includes signal lines S1 to S3. Scanning line G1 is adjacent to scanning line G2. Scanning lines G1 and G2 are arranged in the second direction Y with a pitch PG1 (the fourth pitch). Scanning line G3 is adjacent to scanning line G4. Scanning lines G3 and G4 are arranged in the second direction Y with a pitch PG2 (the fourth pitch). Signal line S1 is adjacent to signal line S2. Signal lines S1 and S2 are arranged in the first direction X with a pitch PS1 (the third pitch). Signal line S2 is adjacent to signal line S3. Signal lines S2 and S3 are arranged in the first direction X with a pitch PS2 (the third pitch). Pixel electrode PE1 is surrounded by scanning lines G1, G2 and signal lines S1, S2. Pixel electrode PE2 is surrounded by scanning lines G3, G4 and signal lines S1, S2. Pixel electrode PE3 is surrounded by scanning lines G1, G2 and signal lines S2, S3. Pixel electrode PE4 is surrounded by scanning lines G3, G4 and signal lines S2, S3. Pixel electrodes PE1 and PE2 are electrically connected to signal line S1, for example. Pixel electrodes PE3 and PE4 are electrically connected to signal line S2, for example.

[0055] The plurality of first structures 41 overlap pixel electrodes PE1 and PE3. Also, in the example of FIG. 8, the plurality of first structures 41 overlap scanning lines G1, G2 and signal lines S1, S2, S3. In other words, a pair of scanning lines G1, G2 located on both sides of pixel electrode PE1 among the plurality of scanning lines G, and a pair of signal lines S1, S2 located on both sides of pixel electrode PE1 among the plurality of signal lines S overlap the plurality of first structures 41. Similarly, a pair of scanning lines G1, G2 located on both sides of pixel electrode PE3 among the plurality of scanning lines G, and a pair of signal lines S2, S3 located on both sides of pixel electrode PE1 among the plurality of signal lines S overlap the plurality of first structures 41.

[0056] In the illustrated example, each of the first structures 41 overlapping the pixel electrode PE1 has the same shape and has substantially equal areas. In the example of FIG. 8, the plurality of first structures 41 are formed in a square shape, but the present invention is not limited to this example. For example, the plurality of first structures 41 may be formed in a rectangular shape or a circular shape. Also, in the example of FIG. 8, the area of each of the plurality of first structures 41 is smaller than the area of each of the pixel electrodes PE1 and PE3. Note that the number of the first structures 41 overlapping the pixel electrodes PE1 and PE3 is not limited to the illustrated example.

[0057] In the present embodiment, the plurality of first structures 41 are regularly arranged. In the example of FIG. 8, the plurality of first structures 41 are arranged in a staggered pattern. Specifically, the first structures 41 arranged in a line parallel to the first direction X and the first structures 41 arranged in a line shifted by one row in the second direction Y from the line are arranged with a 1 / 2 pitch shift in the first direction X.

[0058] As shown in FIG. 8, the plurality of first structures 41 are each arranged at a pitch PX1 (first pitch) in the first direction X. Also, the plurality of first structures 41 are each arranged at a pitch PY1 (second pitch) in the second direction Y. In the example of FIG. 8, the pitch PY1 is equal to the pitch PX1. Here, the pitch PX1 is the distance along the first direction X between the centers of two adjacent first structures on a straight line LX1 parallel to the first direction X (the extending direction of the scanning lines G1 to G4). The pitch PY1 is the distance along the second direction Y between the centers of two adjacent first structures on a straight line LY parallel to the second direction Y (the extending direction of the signal lines S1 to S3). Note that the first structure 41 only needs to be arranged so that the pitch PX1 and the pitch PY1 are equal, and it does not necessarily have to be arranged in a staggered pattern.

[0059] The second structure 42 has a plurality of openings AP as described above. The plurality of openings AP overlap the pixel electrode PE2. Also, in the example of FIG. 8, the plurality of openings AP overlap the scanning lines G3, G4 and the signal lines S1, S2, S3. In other words, a pair of scanning lines G3, G4 located on both sides of the pixel electrode PE2 among the plurality of scanning lines G, and a pair of signal lines S1, S2 located on both sides of the pixel electrode PE2 among the plurality of signal lines S overlap the plurality of openings AP. Similarly, a pair of scanning lines G3, G4 located on both sides of the pixel electrode PE4 among the plurality of scanning lines G, and a pair of signal lines S2, S3 located on both sides of the pixel electrode PE4 among the plurality of signal lines S overlap the plurality of openings AP.

[0060] In the illustrated example, each of the openings AP overlapping the pixel electrode PE2 has the same shape and has substantially equal area. In the example of FIG. 8, the plurality of openings AP are formed in a square shape, but it is not limited to this example. For example, the plurality of openings AP may be formed in a rectangular shape or a circular shape. Also, in the example of FIG. 8, the area of each of the plurality of openings AP is smaller than the area of each of the pixel electrodes PE2, PE4. Note that the number of openings AP overlapping the pixel electrodes PE2, PE4 is not limited to the illustrated example.

[0061] In this embodiment, the plurality of openings AP are regularly arranged. In the example of FIG. 8, the plurality of openings AP are arranged in a staggered pattern. Specifically, the openings AP arranged on a straight line parallel to the first direction X and the openings AP arranged on a straight line shifted by one row in the second direction Y from the straight line are arranged with a 1 / 2 pitch shift in the first direction X.

[0062] As shown in FIG. 8, the plurality of openings AP are arranged side by side at a pitch PX2 (first pitch) in the first direction X. Also, the plurality of openings AP are arranged side by side at a pitch PY2 (second pitch) in the second direction Y. In the example of FIG. 8, the pitch PY2 is equal to the pitch PX2. Here, the pitch PX2 is the distance along the first direction X between the centers of two adjacent openings AP on a straight line LX2 parallel to the first direction X (the extending direction of the scanning lines G1 to G4). The pitch PY2 is the distance along the second direction Y between the centers of two adjacent openings AP on a straight line LY parallel to the second direction Y (the extending direction of the signal lines S1 to S3). Note that the openings AP may be arranged such that the pitch PX2 and the pitch PY2 are equal, and they do not necessarily have to be arranged in a staggered manner.

[0063] The pitch PS1 is desirably an integral multiple of the pitches PX1 and PX2. In the example of FIG. 8, the pitch PS1 is twice the pitches PX1 and PX2. Similarly, it is desirable that the pitch PS2 is an integral multiple of the pitches PX1 and PX2, the pitch PG1 is an integral multiple of the pitch PY1, and the pitch PG2 is an integral multiple of the pitch PY2. In the example of FIG. 8, the pitch PS2 is twice the pitches PX1 and PX2, the pitch PG1 is twice the pitch PY1, and the pitch PG2 is twice the pitch PY2.

[0064] According to such a configuration, the total area of the first structure 41 overlapping one pixel electrode PE in a plan view is equal for each of the pixel electrodes PE arranged along the first direction X. In the example of FIG. 8, the total area of the first structure 41 overlapping the pixel electrode PE1 is equal to the total area of the first structure 41 overlapping the pixel electrode PE3. Similarly, the total area of the openings AP overlapping one pixel electrode PE in a plan view is equal for each of the pixel electrodes PE arranged along the first direction X. In the example of FIG. 8, the total area of the openings AP overlapping the pixel electrode PE2 is equal to the total area of the openings AP overlapping the pixel electrode PE4.

[0065] As a result, in the pixel electrodes PE arranged in the first direction X, the amount of light incident on each of the pixel electrodes PE becomes substantially equal. Therefore, it is possible to suppress the occurrence of moiré caused by the difference in the amount of light per pixel, and it is possible to suppress a decrease in display quality.

[0066] Also, according to such a configuration, the pattern of the first structure 41 overlapping each of the pixel electrodes PE is the same for each of the pixel electrodes PE arranged in the first direction X. In the example of FIG. 8, the pattern of the first structure 41 overlapping the pixel electrode PE1 is the same as the pattern of the first structure 41 overlapping the pixel electrode PE3. Further, the pattern of the first structure 41 overlapping each of the pixel electrodes PE is the same for each of the pixel electrodes PE arranged in the first direction and including the pixel electrodes PE1 and PE3.

[0067] Similarly, the pattern of the aperture AP overlapping each of the pixel electrodes PE is the same for each of the pixel electrodes PE arranged in the first direction X. In the example of FIG. 8, the pattern of the aperture AP overlapping the pixel electrode PE2 is the same as the pattern of the aperture AP overlapping the pixel electrode PE4. Further, the pattern of the aperture AP overlapping each of the pixel electrodes PE is the same for each of the pixel electrodes PE arranged in the first direction and including the pixel electrodes PE2 and PE4.

[0068] When the pitch of the scanning lines and the signal lines is not an integer multiple of the pitch of the first structure 41 and the aperture AP, the patterns of the first structure 41 and the aperture AP overlapping each of the pixel electrodes PE are different for each of the pixel electrodes PE arranged in the first direction X. In such a configuration, in the first direction X, a dense portion and a sparse portion are formed by the first structure 41 and the aperture AP, and a pattern is generated in a streak shape, which may lead to a decrease in display quality.

[0069] On the other hand, in the present embodiment, the patterns of the first structure 41 and the aperture AP overlapping each of the pixel electrodes PE are the same for each of the pixel electrodes PE arranged in the first direction X. Therefore, it is possible to suppress the occurrence of the above-described streak pattern, and it is possible to suppress a decrease in display quality.

[0070] Further, according to the present embodiment, the area where the first structure 41 overlaps with the pixel electrode PE1 is smaller than the area where the second structure 42 overlaps with the pixel electrode PE2. Also, the area of the first structure 41 in plan view increases as it moves away from the light-emitting element LS, and the area of the aperture AP in plan view decreases as it moves away from the light-emitting element LS. Therefore, the area of the region where the light irradiated from the light-emitting element LS can enter the pixel electrode PE1 is smaller than the area of the region where the light irradiated from the light-emitting element LS can enter the pixel electrode PE2. On the other hand, the light irradiated from the light-emitting element LS attenuates as it moves away from the light-emitting element LS. Therefore, the luminance of the light in the region close to the light-emitting element LS is higher than the luminance of the light in the region away from the light-emitting element LS. That is, the luminance of the light incident on the pixel electrode PE1 is higher than the luminance of the light incident on the pixel electrode PE2. Accordingly, the amount of light in the pixel electrode PE1 and the pixel electrode PE2 can be equalized, and a decrease in display quality can be suppressed.

[0071] Also, as described above, since the light-emitting element LS faces only the side surface 30S of the third transparent substrate 30 in the second direction Y, the light irradiated from the light-emitting element LS hardly directly enters the adhesive AD and the display panel PNL. Therefore, it is possible to suppress a decrease in display quality due to undesired scattering in the adhesive AD and the seal SE. Further, the luminance gradient caused by the light emitted from the light-emitting element LS directly entering the first substrate SUB1 and the second substrate SUB2 is alleviated.

[0072] Also, generally, a siloxane-based resin or a fluorine compound can be used for the low refractive index layer that reflects the light emitted from the light-emitting element. However, the siloxane-based resin is likely to gasify and may have various adverse effects during the production process. Also, the movement to regulate fluorine compounds is intensifying globally. On the other hand, according to the present embodiment, the low refractive index layer AR is an air layer, and the aperture AP is filled with air. Also, the structure 40 is formed of a material such as an acrylic-based resin or an epoxy-based resin. Therefore, according to the present embodiment, it is possible to provide a display device capable of suppressing a decrease in display quality without using a low refractive index material such as a siloxane-based resin or a fluorine compound.

[0073] FIG. 9 is a plan view showing another example of the relationship between the structure 40 and the pixel electrode PE. FIG. 9 is different from FIG. 8 in that the first structure 41 and the opening AP do not overlap the scanning lines G1 to G4 and the signal lines S1 to S3.

[0074] Also in FIG. 9, similar to FIG. 8, the pitch PS1 is an integral multiple (2 times) of the pitches PX1 and PX2, the pitch PS2 is an integral multiple (2 times) of the pitches PX1 and PX2, the pitch PG1 is an integral multiple (2 times) of the pitch PY1, and the pitch PG2 is an integral multiple (2 times) of the pitch PY2. Therefore, as shown in FIG. 9, even if the first structure 41 and the opening AP do not overlap the scanning lines G1 to G4 and the signal lines S1 to S3, the same effects as those described with reference to FIG. 8 can be obtained.

[0075] Here, as an example of a method for forming the structure 40, a method of forming the structure 40 by applying a material for forming the structure 40 onto the second transparent substrate 20 or the third transparent substrate 30, drying it, and patterning it can be mentioned. In such a manufacturing process, positional accuracy of patterning and bonding accuracy of the substrates are required. On the other hand, according to the present embodiment, as shown in FIGS. 8 and 9, by setting the pitches of the scanning lines and the signal lines to integral multiples of the pitches of the first structure 41 and the opening AP, even if the positions of the first structure 41 and the opening AP deviate from the design values in patterning or substrate bonding, the above-described effects can be obtained.

[0076] [Second Embodiment] Next, the second embodiment will be described. The same or similar elements as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0077] FIG. 10 is a diagram showing a schematic configuration example of the display device DSP according to the second embodiment. In the present embodiment, the shape of the structure 40 is different from that in the first embodiment.

[0078] The structure 40 includes a plurality of strip portions 43 arranged at intervals in the first direction X. Each of the strip portions 43 extends along the second direction Y. A low refractive index layer AR is disposed between adjacent strip portions 43. The plurality of strip portions 43 are disposed in the display area DA. However, the plurality of strip portions 43 may be disposed in the display area DA and the peripheral area SA.

[0079] In the example of FIG. 10, the strip portion 43 is formed in a trapezoidal shape in which the width WL (the length along the first direction X) increases as it moves away from the plurality of light emitting elements LS in the second direction Y. In one example, the pixel electrode PE overlaps two adjacent strip portions 43 in plan view. Therefore, the area where the strip portion 43 overlaps with the pixel electrode PE1 is smaller than the area where the strip portion 43 overlaps with the pixel electrode PE2.

[0080] FIG. 11 is a schematic cross-sectional view of the display device DSP along the line B-B' shown in FIG. 10. In the example shown in FIG. 11, the light L3 propagating through the third transparent substrate 30 is reflected at the boundary between the lower surface 30L of the third transparent substrate 30 and the low refractive index layer AR. Thereafter, the light L3 is reflected at the boundary between the upper surface 30U of the third transparent substrate 30 and the air, and is incident on the display panel PNL through the first structure 41.

[0081] According to the second embodiment, as in the first embodiment, the area of the region where the light emitted from the light emitting element LS can be incident on the pixel electrode PE1 is smaller than the area of the region where the light emitted from the light emitting element LS can be incident on the pixel electrode PE2. Therefore, the illumination light amounts at the pixel electrode PE1 and the pixel electrode PE2 can be equalized.

[0082] As described above, based on the display device described as an embodiment of the present invention, all display devices that can be appropriately designed and modified by those skilled in the art also belong to the scope of the present invention as long as they include the gist of the present invention.

[0083] Those skilled in the art can conceive of various modifications within the scope of the idea of the present invention, and these modifications are also understood to fall within the scope of the present invention. For example, with respect to the above-described embodiments, those in which a person skilled in the art appropriately adds, deletes, or changes the design of components, or adds, omits, or changes the conditions of the steps, are also included in the scope of the present invention as long as they have the gist of the present invention.

[0084] In addition, with respect to other operational effects brought about by the aspects described in the above-described embodiments, those that are obvious from the description of this specification or that can be appropriately conceived by those skilled in the art are naturally understood to be brought about by the present invention.

Description of Reference Numerals

[0085] DSP... Display device, PNL... Display panel, PX... Pixel, DA... Display area, SA... Peripheral area, MA... Mounting area, 10... First transparent substrate, 20... Second transparent substrate, 30... Third transparent substrate, LC... Liquid crystal layer, 31... Polymer, 32... Liquid crystal molecules, LU... Light source unit, LS... Light-emitting element, LG... Light guide, AD... Adhesive, AP... Aperture, AR... Low refractive index layer, G, G1 to G4... Scanning lines, S, S1 to S4... Signal lines, PE, PE1 to 4... Pixel electrodes, 40... Structure, 41... First structure, 42... Second structure, 43... Band portion.

Claims

1. A first transparent substrate, a second transparent substrate facing the first transparent substrate, a polymer-dispersed liquid crystal layer positioned between the first transparent substrate and the second transparent substrate, a first pixel electrode and a second pixel electrode positioned between the first transparent substrate and the liquid crystal layer, and a common electrode positioned between the second transparent substrate and the liquid crystal layer and facing the first pixel electrode and the second pixel electrode, a display panel comprising; 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 and facing the second transparent substrate; A structure in contact with the second transparent substrate and the third transparent substrate for guiding light emitted from the plurality of light-emitting elements from the third transparent substrate to the liquid crystal layer, comprising; The second pixel electrode is spaced apart from the plurality of light-emitting elements more than the first pixel electrode; The structure includes a plurality of first structures overlapping the first pixel electrode and a second structure having a plurality of openings overlapping the second pixel electrode; The plurality of first structures and the plurality of openings are each arranged at a first pitch in the first direction and are each arranged at a second pitch equal to the first pitch in a second direction orthogonal to the first direction; An area where the first structure overlaps the first pixel electrode is smaller than an area where the second structure overlaps the second pixel electrode; A display device.

2. The display panel further includes a plurality of scanning lines positioned between the first transparent substrate and the liquid crystal layer, and a plurality of signal lines intersecting the plurality of scanning lines; The plurality of signal lines are arranged at a third pitch in the first direction; The plurality of scanning lines are arranged at a fourth pitch in the second direction; The third pitch is an integer multiple of the first pitch; The fourth pitch is an integer multiple of the second pitch; The display device according to Claim 1.

3. A pair of scanning lines positioned on both sides of the first pixel electrode among the plurality of scanning lines, and a pair of signal lines positioned on both sides of the first pixel electrode among the plurality of signal lines overlap the plurality of first structures; A pair of scanning lines positioned on both sides of the second pixel electrode among the plurality of scanning lines, and a pair of signal lines positioned on both sides of the second pixel electrode among the plurality of signal lines overlap the plurality of openings; The display device according to Claim 2.

4. A refractive index of the structure is equivalent to a refractive index of each of the second transparent substrate and the third transparent substrate; The display device according to Claim 1.

5. The refractive index difference between the structure and the second transparent substrate, and the refractive index difference between the structure and the third transparent substrate are each 0.05 or less. The display device according to claim 1.

6. The area of each of the plurality of first structures is smaller than the area of the first pixel electrode. The display device according to claim 1.

7. The area of each of the plurality of openings is smaller than the area of the second pixel electrode. The display device according to claim 1.

8. The plurality of first structures are arranged in a staggered pattern. The display device according to claim 1.

9. The plurality of openings are arranged in a staggered pattern. The display device according to claim 1.

10. The structure is formed of an acrylic resin or an epoxy resin. The display device according to claim 1.

11. Furthermore, an adhesive for bonding the second transparent substrate and the third transparent substrate is provided. The adhesive extends along the first direction and is located between the plurality of light-emitting elements and the structure in a plan view. The display device according to claim 1.

12. Furthermore, an adhesive for bonding the second transparent substrate and the third transparent substrate is provided. The adhesive surrounds the structure. The display device according to claim 1.

13. The refractive index of the adhesive is equivalent to the refractive index of the structure. The display device according to claim 11 or 12.

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