Display device

Abstract

To provide a display device capable of inhibiting deterioration of display quality.SOLUTION: A light guide element includes a third substrate and a transparent layer having refractive index lower than that of the third substrate. The transparent layer includes a plurality of band parts arrayed in a first direction, the band parts each having a triangular shape with a first side, a second side and a third side. The first side is shorter than the second side and the third side; the second side is shorter than the third side; and the first side extends along the first direction. An extension direction of a virtual line connecting a first point at the center of the first side and a second point where the second side intersects the third side is defined as an extension direction of each of the plurality of band parts. The extension direction is inclined at 4° with respect to a second direction. Length of the first side is shorter than a gap between a plurality of signal lines.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] A display device has been proposed that can switch between a scattering state, in which incident light is scattered, and a transmission state, in which incident light is transmitted, by using polymer dispersed liquid crystal (PDLC). Transparent display devices using PDLC adopt an edge light method in which a light source is placed at the edge of a light guide plate. However, when the edge light method is used in a PDLC display device, there is a problem in that the brightness of the display surface decreases with increasing distance from the light source.

[0003] In order to solve such problems, a display device has been developed in which a light guide element having a transparent layer with a low refractive index arranged in an isosceles triangle shape is provided on a liquid crystal panel (see Patent Documents 3 and 4).

[0004] However, the display devices shown in Patent Documents 3 and 4 have a new problem in that moire occurs between the transparent layer and pixels in the isosceles triangle shape. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-032411 A [Patent Document 2] JP 2020-016724 A [Patent Document 3] JP 2022-174556 A [Patent Document 4] International Publication No. 2022 / 158477 [Patent Document 5] International Publication No. 2022 / 158478 [Patent Document 6] International Publication No. 2020 / 022112 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present embodiment is to provide a display device capable of suppressing degradation in display quality. [Means for solving the problem]

[0007] A display device according to an embodiment includes: A display panel including a first substrate, a second substrate, and a liquid crystal layer having a polymer dispersed liquid crystal; A plurality of light emitting elements; A light guide element; Equipped with The first substrate is A first substrate; A plurality of scanning lines provided on the first substrate, extending along a first direction, and arranged side by side along a second direction intersecting the first direction; A plurality of signal lines provided on the first base material, extending along the second direction, and arranged side by side along the first direction; a plurality of switching elements electrically connected to the plurality of scanning lines and the plurality of signal lines; A plurality of pixel electrodes electrically connected to the plurality of switching elements; Equipped with The second substrate is A second substrate; a common electrode facing the plurality of pixel electrodes; Equipped with The light guide element is A third substrate; a transparent layer having a refractive index lower than the refractive index of the third substrate; Equipped with the transparent layer has a plurality of strips arranged side by side in the first direction, Each of the plurality of band portions has a triangular shape having a first side, a second side, and a third side; The first side is shorter than the second side and the third side, The second side is shorter than the third side, The first side extends along the first direction, The extension direction of each of the plurality of band portions is defined as an extension direction of a virtual line connecting a first point at the center of the first side and a second point at which the second side and the third side intersect, The stretching direction is inclined at 4° with respect to the second direction, The length of the first side is shorter than the spacing between the signal lines. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a plan view showing a schematic configuration of a display device according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a schematic configuration of the display panel shown in FIG. [Diagram 3] FIG. 3 is an exploded perspective view showing a main part of the display device. [Figure 4] FIG. 4 is a cross-sectional view showing an example of a schematic configuration of a display device. [Diagram 5] FIG. 5 is a plan view illustrating an example of a schematic configuration of a light guide element. [Figure 6] FIG. 6 is a plan view illustrating an example of a schematic configuration of a light guide element. [Figure 7] FIG. 7 shows the results of a simulation of the moire intensity and pitch when the pitch of the bands is changed. [Figure 8] FIG. 8 is a diagram showing that no moire occurs when the extending direction of the strip is inclined. [Figure 9] FIG. 9 is a diagram showing that moire occurs when the extending direction of the strip is not inclined. [Figure 10] FIG. 10 shows the results of a simulation showing the occurrence of moire when the pitch of the bands is changed and when the stretching direction of the bands is changed. [Figure 11] FIG. 11 shows the results of a simulation showing how moire occurs when the pitch of the bands is changed and when the stretching direction of the bands is changed. [Figure 12] FIG. 12 shows the results of a simulation showing the occurrence of moire when the pitch of the bands is changed and when the stretching direction of the bands is changed. [Figure 13] FIG. 13 shows the results of a simulation showing the occurrence of moire when the pitch of the bands is changed and when the stretching direction of the bands is changed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Note that the disclosure is merely an example, and those who are skilled in the art can easily come up with appropriate modifications while maintaining the gist of the invention, which are naturally included in the scope of the present invention. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. In addition, in this specification and each figure, elements similar to those described above with respect to the previous figures may be given the same reference numerals, and detailed explanations may be omitted as appropriate.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments described in this specification are not general, but are embodiments describing the same or corresponding special technical features of the present invention.

[0011] In this embodiment, the first direction X, the second direction Y, and the third direction Z are perpendicular to each other, but may intersect at an angle other than 90 degrees. The direction toward the tip of the arrow of the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow of the third direction Z is defined as down or downward. The first direction X, the second direction Y, and the third direction Z may also be called the X direction, the Y direction, and the Z direction, respectively.

[0012] Furthermore, in the case of "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 located away from the first member. In the latter case, a third member may be interposed between the first and second members. On the other hand, in the case of "a second member above the first member" and "a second member below the first member," the second member is in contact with the first member.

[0013] Also, it is assumed that an observation position for observing the display device is located at the tip side of the arrow in the third direction Z, and a planar view refers to a view from this observation position toward the XY plane defined by the first direction X and the second direction Y. A cross-sectional view refers to a view of a cross section of the display device in the XZ plane defined by the first direction X and the third direction Z, or in the YZ plane defined by the second direction Y and the third direction Z.

[0014] [Embodiment] FIG. 1 is a plan view showing a schematic configuration of a display device according to an embodiment. In this embodiment, a liquid crystal display device to which a polymer dispersed liquid crystal is applied will be described as an example of the display device DSP. The display device DSP includes a display panel PNL, an IC chip ICP, and a wiring board FPC1.

[0015] The display panel PNL includes a substrate SUB1, a substrate SUB2, a liquid crystal layer LC, and a seal SAL. The substrates SUB1 and SUB2 are formed in the shape of flat plates parallel to the XY plane. The substrates SUB1 and SUB2 overlap each other in a planar view. The substrates SUB1 and SUB2 are bonded together by the seal SAL. The liquid crystal layer LC is held between the substrates SUB1 and SUB2, and is sealed by the seal SAL.

[0016] As shown enlarged and schematic in FIG. 1, the liquid crystal layer LC includes a polymer-dispersed liquid crystal including a polymer PLM and liquid crystal molecules LCM. In one example, the polymer PLM is a liquid crystal polymer. The polymer PLM is formed in stripes extending along a first direction X. The liquid crystal molecules LCM are dispersed in gaps in the polymer PLM, and are oriented such that their major axes are aligned along the first direction X. Each of the polymer PLM and the liquid crystal molecules LCM has optical anisotropy or refractive index anisotropy. The responsiveness of the polymer PLM to an electric field is lower than the responsiveness of the liquid crystal molecules LCM to an electric field.

[0017] In one example, the alignment direction of the polymer PLM hardly changes regardless of the presence or absence of an electric field. On the other hand, the alignment direction of the liquid crystal molecules LCM changes in response to an electric field when a high voltage equal to or higher 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 PLM and the liquid crystal molecules LCM 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 PLM and the liquid crystal molecules LCM cross each other, and light incident on the liquid crystal layer LC is scattered within the liquid crystal layer LC (scattered state).

[0018] The display panel PNL includes a display area DA for displaying an image and a frame-shaped non-display area NDA surrounding the display area DA. The seal SAL is located in the non-display area NDA. The display area DA includes pixels PX arranged in a matrix in the first direction X and the second direction Y.

[0019] 1, each of the pixels 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 of, for example, a thin film transistor (TFT), and is electrically connected to the scanning line GL and the signal line SL.

[0020] The multiple scanning lines GL extend along a first direction X and are arranged side by side along a second direction Y (see FIG. 6 described later). Each scanning line GL is electrically connected to the switching elements SW in each of the pixels PX arranged in the first direction X.

[0021] The signal lines SL extend in a direction parallel to the second direction Y and are arranged side by side in the first direction X (see FIG. 6 described later). Each signal line SL is electrically connected to the switching elements SW in each of the pixels PX arranged in the second direction Y. The signal lines SL intersect with the scanning lines GL.

[0022] As shown in Fig. 1 and Fig. 6 described later, each of the pixels PX occupies an area defined by two adjacent signal lines SL and two adjacent scanning lines GL. That is, the pixels PX are arranged at a predetermined pitch along each of the first direction X and the second direction Y. The pitch of the pixels PX along the first direction X is equal to the pitch of the signal lines SL. The pitch of the pixels PX along the second direction Y is equal to the pitch of the scanning lines GL.

[0023] The pixel electrodes PE are electrically connected to the switching elements SW. Each pixel electrode PE faces a common electrode CE, and drives the liquid crystal layer LC (particularly, liquid crystal molecules LCM) by an electric field generated between the pixel electrodes PE and the common electrode CE.

[0024] The scanning lines GL, signal lines SL, switching elements SW, and pixel electrodes PE are provided on a substrate SUB1. 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.

[0025] The substrate SUB1 has ends E11 and E14 extending along the first direction X, and ends E12 and E13 extending along the second direction Y. The substrate SUB2 has ends E21 and E24 extending along the first direction X, and ends E22 and E23 extending along the second direction Y.

[0026] 1, the ends E12 and E22, the ends E13 and E23, and the ends E14 and E24 overlap each other in a plan view, but they do not have to overlap. The end E21 is located between the end E11 and the display area DA in a plan view. The substrate SUB1 has an extension area Ex between the end E11 and the end E21.

[0027] The IC chip ICP and the wiring board FPC1 are each connected to the extension region Ex. The IC chip ICP has built-in, for example, a display driver that outputs signals necessary for image display. The wiring board FPC1 is a bendable flexible printed circuit board. The IC chip ICP may be connected to the wiring board FPC1. The IC chip ICP and the wiring board FPC1 may read out signals from the display panel PNL, but mainly function as a signal source that supplies signals to the display panel PNL.

[0028] FIG. 2 is a cross-sectional view showing a schematic configuration of the display panel shown in FIG. The substrate SUB1 includes a base material BA1, an insulating layer INS1, an insulating layer INS2, a capacitance electrode CSE, a switching element SW, a pixel electrode PE, and an alignment film AL1. The substrate SUB1 further includes the scanning lines GL and the signal lines SL shown in FIG.

[0029] The base material BA1 is made of a light-transmitting material. The base material BA1 has a main surface (lower surface) B1A and a main surface (upper surface) B1B opposite to the main surface 10A. The switching element SW is disposed on the main surface B1B.

[0030] The insulating layer INS1 covers the switching element SW. The capacitance electrode CSE is located between the insulating layer INS1 and the insulating layer INS2. The pixel electrode PE is disposed for each pixel PX on the insulating layer INS2. The pixel electrode PE is electrically connected to the switching element SW through an opening OP of the capacitance electrode CSE. The pixel electrode PE overlaps with the capacitance electrode CSE with the insulating layer INS2 sandwiched therebetween to form a capacitance CS of the pixel PX. The alignment film AL1 covers the pixel electrode PE.

[0031] The substrate SUB2 includes a base material BA2, a light-shielding layer BM, a common electrode CE, and an alignment film AL2.

[0032] The base material BA2 is formed of a light-transmitting material. The base material BA2 has a main surface (lower surface) B2A and a main surface (upper surface) B2B opposite to the main surface B2A. The main surface B2A of the base material BA2 faces the main surface B2B of the base material BA1. The light-shielding layer BM and the common electrode CE are disposed on the main surface B2A. The light-shielding layer BM is located, for example, directly above the switching element SW and directly above the scanning line GL and the signal line SL (not shown).

[0033] The common electrode CE is disposed across multiple pixels PX and directly covers the light-shielding layer BM. The common electrode CE faces the pixel electrodes PE. The common electrode CE is electrically connected to the capacitive electrode CSE and has the same potential as the capacitive electrode CSE. The alignment film AL2 covers the common electrode CE. The liquid crystal layer LC is located between the principal surface B1B and the principal surface B2A and is in contact with the alignment films AL1 and AL2.

[0034] The base material BA1 and the base material BA2 are insulating base materials made of glass, plastic, etc. The principal surface B1A, the principal surface B1B, the principal surface B2A, and the principal surface B2B are surfaces substantially parallel to the XY plane.

[0035] The insulating layer INS1 is formed of a transparent insulating material such as silicon oxide, silicon nitride, silicon oxynitride, acrylic resin, etc. In one example, the insulating layer INS1 includes an inorganic insulating layer and an organic insulating layer. The insulating layer INS2 is an inorganic insulating layer such as silicon nitride.

[0036] The capacitance electrode CSE, 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).

[0037] 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 made of an opaque metal material such as molybdenum (Mo), aluminum (Al), tungsten (W), titanium (Ti), or silver (Ag).

[0038] The alignment films AL1 and AL2 are horizontal alignment films having an alignment regulating force substantially parallel to the XY plane. In one example, the alignment films AL1 and AL2 are aligned along the first direction X. The alignment treatment may be a rubbing treatment or a photo-alignment treatment.

[0039] FIG. 3 is an exploded perspective view showing a main part of the display device. The display device DSP includes a plurality of light emitting elements LD and a light guide element LG in addition to the display panel PNL. The substrate SUB1, the substrate SUB2, and the light guide element LG are arranged in the third direction Z in this order.

[0040] The light emitting elements LD are arranged at intervals in the first direction X. The light emitting elements LD are connected to a wiring board FPC2. The light emitting elements LD are, for example, light emitting diodes. Although not described in detail, the light emitting elements LD include a red light emitting element, a green light emitting element, and a blue light emitting element. Light emitted from the light emitting elements LD travels along the direction of the arrow indicating the second direction Y.

[0041] The light guide element LG includes a base material BA3 and a transparent layer LRI. The base material BA3 is formed of a material having light-transmitting properties. The base material BA3 is an insulating base material such as glass or plastic, and has a refractive index n1. In one example, the base material BA3 is a single base material, not a combination of multiple base materials.

[0042] The base material BA3 has a main surface (lower surface) B3A, a main surface (upper surface) B3B opposite to the main surface B3A, a first side surface SS1, a second side surface SS2, a third side surface SS3, and a fourth side surface SS4. The main surfaces B3A and B3B are substantially parallel to the XY plane. The main surface B3A faces the main surface B2B of the base material BA2.

[0043] The first side surface SS1 faces the multiple light-emitting elements LD. The first side surface SS1 and the fourth side surface SS4 extend in the first direction X. The second side surface SS2 and the third side surface SS3 extend in the second direction Y. The first side surface SS1 and the fourth side surface SS4 face each other. The second side surface SS2 and the third side surface SS3 face each other. The second side surface SS2 and the third side surface SS3 intersect with the first side surface SS1.

[0044] As described later, the base material BA3 is bonded to the base material BA2 with a transparent layer LRI sandwiched therebetween. In the example shown in Fig. 3, the first side surface SS1 is located directly above the end E21 of the substrate SUB2, but may be located directly above the extension region Ex or may be located further outward than the end E11.

[0045] The transparent layer LRI is disposed on the main surface B3A. The transparent layer LRI has a refractive index n2 lower than the refractive index n1 of the base material BA3. The transparent layer LRI includes a plurality of band portions BND arranged at intervals. Each of the band portions BND extends along a predetermined direction. The main surface B3A is exposed between adjacent band portions BND. The transparent layer LRI also includes a frame portion FRM surrounding the plurality of band portions BND.

[0046] The area of ​​the main surface B3A that is occupied by the strip portions BND overlaps with the display area DA. The detailed shape of the transparent layer LRI will be described later.

[0047] The base material BA3 is formed of an organic material such as glass, polymethylmethacrylate (PMMA), polycarbonate (PC), etc. The transparent layer LRI is formed of an organic material such as a siloxane-based resin, a fluorine-based resin, etc. The refractive index n1 of the base material BA3 is about 1.5, and the refractive index n2 of the transparent layer LRI is about 1.0 to 1.4.

[0048] FIG. 4 is a cross-sectional view showing an example of a schematic configuration of a display device. The light LT emitted from the light emitting element LD is incident on the first side surface SS1 of the base material BA3. The light LT incident on the first side surface SS1 is guided inside the base material BA3 while being reflected by the main surface B3B and the transparent layer LRI. The main surface B3B is the interface between the base material BA3 and the air layer.

[0049] As described above, the light LT is reflected by the principal surface B3B and the transparent layer LRI. However, when the light LT passes through the region NLR of the principal surface B3A where the transparent layer LRI is not provided, the light LT passes through the region NLR and enters the display panel PNL. Note that the light LT may also pass through the transparent layer LRI and enter the display panel PNL.

[0050] By being reflected by the transparent layer LRI, the light LT can be guided from the first side surface SS1, which is the incident surface, to the fourth side surface SS4 opposite to the first side surface SS1. The light LT that is incident on the display panel PNL in the region NLR is diffused or transmitted by the liquid crystal layer LC of the display panel PNL. As a result, an image is displayed on the display device DSP.

[0051] The density of the transparent layer LRI is changed according to the distance from the light emitting element LD. Specifically, the area of ​​the transparent layer LRI is increased as it is closer to the light emitting element LD. As a result, in the area close to the light emitting element LD, the amount of light LT reflected by the transparent layer LRI is greater than the amount of light LT incident on the display panel PNL.

[0052] On the other hand, as described above, the area of ​​the transparent layer LRI is smaller in the region far from the light emitting element LD, so that in the region far from the light emitting element LD, the amount of light LT incident on the display panel PNL is greater than the amount of light LT reflected by the transparent layer LRI.

[0053] To achieve this, it is preferable to provide the transparent layer LRI as a triangular strip BND, as shown in Fig. 3. The base of the triangle is located in a region close to the light-emitting element LD. The apex of the triangle is located in a region far from the light-emitting element LD.

[0054] With the above configuration, it is possible to guide the light LT to an area far from the light emitting element LD, and it is possible to make the brightness of the image displayed on the display device DSP uniform.

[0055] However, as described above, a new problem occurs in that moire occurs between the transparent layer LRI and the pixel PX, which will be described in detail below with reference to the drawings.

[0056] 5 and 6 are plan views showing examples of schematic configurations of light guide elements. As described above, the transparent layer LRI provided on the light guide element LG includes a plurality of strip portions BND and a frame portion FRM surrounding the plurality of strip portions BND. Fig. 5 shows only the plurality of strip portions BND. Fig. 6 shows only the plurality of strip portions BND, the plurality of pixels PX, the plurality of signal lines SL, and the plurality of scanning lines GL. In Fig. 6, the shaded area indicates one pixel PX.

[0057] Each of the multiple band portions BND has a triangular shape. The triangular band portion BND has points LP, RP, and CP. The side formed by points LP and RP is called side TH. The side formed by points CP and LP is called side NH. The side formed by points CP and RP is called side MH. The point on side TH that is equidistant from points LP and RP is called point HP.

[0058] A plurality of band portions BND are arranged side by side along the first direction X. The sides TH of the plurality of band portions BND form a straight line extending along the first direction X. In Fig. 4, the straight line formed by the sides TH of the plurality of band portions BND coincides with the first side surface SS1. However, there may be a gap between the straight line formed by the sides TH of the plurality of band portions BND and the first side surface SS1.

[0059] The length of side NH is longer than the length of side MH. The length of side TH is shorter than the lengths of sides NH and MH. In other words, if the lengths of sides NH, MH, and TH are nh, mh, and th, respectively, then nh>mh>th holds.

[0060] From the above, the shape of the band portion BND is a triangle, but not an isosceles triangle. The imaginary line connecting the points HP and CP is defined as an imaginary line ES. The extending direction of the imaginary line ES is defined as the extending direction of the band portion BND. The extending direction of the band portion BND is inclined at an angle θ with respect to the second direction Y.

[0061] An imaginary line MS that passes through point HP and extends along the second direction Y does not pass through point CP. Also, an imaginary line KS that passes through point CP, which is the vertex, and extends along the second direction Y does not pass through point HP.

[0062] Consider a case where the extension direction of the band portion BND is parallel to the second direction Y. The extension direction of the multiple signal lines SL is also parallel to the second direction Y. If the extension direction of the band portion BND and the extension direction of the signal lines SL are the same, moire will occur between the signal lines SL and the band portion BND.

[0063] However, in the embodiment, the band portion BND is inclined at an angle θ with respect to the second direction Y. This prevents interference between the band portion BND and the signal lines SL, and prevents moire from occurring.

[0064] In this embodiment, the pitch of the band portions BND and the pitch of the signal lines SL are preferably different, because if the pitch of the band portions BND and the pitch of the signal lines SL are the same, moire is likely to occur.

[0065] In this embodiment, the pitch of the band portion BND corresponds to the length th of the side TH. The pitch of the multiple signal lines SL is the distance between the signal lines SL.

[0066] In this embodiment, the pitch of the band portion BND is preferably smaller than the pitch of the signal lines SL. The pitch of the band portion BND, i.e., the length th of the side TH, is preferably 133.2 μm, for example. On the other hand, the pitch of the multiple signal lines SL (the spacing between the signal lines SL) is, for example, 360 μm.

[0067] In this embodiment, the pitch of the band portion BND and the pitch of the signal lines SL are also different, so that the possibility of moire occurring between the signal lines SL and the band portions BND is reduced. By making the extending direction and pitch of the band portion BND different from the extending direction and pitch of the signal lines SL, it is possible to suppress the occurrence of moire.

[0068] The multiple scanning lines GL are arranged side by side at intervals of 360 μm along the second direction Y. In other words, the pitch of the multiple scanning lines GL (the interval between the scanning lines GL) is the same as the pitch of the multiple signal lines SL (the interval between the signal lines SL).

[0069] The interference between the scanning lines GL and the band portions BND has a smaller effect than the interference between the signal lines SL and the band portions BND. The direction in which the scanning lines GL extend is parallel to the first direction X. The direction in which the straight lines formed by the sides TH of the multiple band portions BND extend is parallel to the first direction X. However, the sides TH of the band portions BND exist only in the vicinity of the first side surface SS1. Therefore, moire caused by the interference between the scanning lines GL and the band portions BND is unlikely to occur.

[0070] 5 and 6, the area occupied by the multiple bands BND overlaps with the display area DA as described above. The area occupied by the bands BND may be larger than the display area DA. In other words, the length of each of the multiple bands BND along the second direction Y is equal to or greater than the length of the display area DA along the second direction Y.

[0071] Fig. 7 shows the results of a simulation of the moire intensity and pitch when the pitch of the strips is changed. As described above, the pitch of the strips BND is equal to the length th of the side TH. In the simulation shown in Fig. 7, as described above, the pitch of the pixels PX, i.e., the spacing between the signal lines SL and the spacing between the scanning lines GL, is set to 360 μm. The direction in which the strips BND extend is tilted by 4° with respect to the second direction Y, as shown in Fig. 5.

[0072] The horizontal axis of Fig. 7 is the pitch (μm) of the band portion BND, the left vertical axis is the moire pitch (μm), and the right vertical axis is the normalized strength of the moire. In Fig. 7, the solid line indicates the moire pitch, and the dotted line indicates the normalized strength of the moire.

[0073] The closer the moire pitch (solid line) is to 0 μm, the less visible the moire. Similarly, the closer the normalized moire intensity (dotted line) is to 0, the less visible the moire. In FIG. 7, both the moire pitch (solid line) and the normalized moire intensity (dotted line) are close to 0 when the pitch of the band portion BND is 133.2 μm. Therefore, a pitch of 133.2 μm is preferable for the band portion BND.

[0074] Fig. 8 is a diagram showing that moire does not occur when the extending direction of the strip is inclined. Fig. 9 is a diagram showing that moire occurs when the extending direction of the strip is not inclined. Fig. 8 and Fig. 9 are each photographs of the display device DSP as viewed from above.

[0075] 8 and 9, the pitch of the band portions BND is 133.2 μm. In FIG. 8, the extending direction of the band portions BND is inclined at 4° with respect to the second direction Y. On the other hand, in FIG. 9, the extending direction of the band portions BND is parallel to the second direction Y. In other words, the extending direction of the band portions BND is not inclined with respect to the second direction Y.

[0076] No moire is observed in Fig. 8. On the other hand, multiple streaks are observed in Fig. 9. In Fig. 9, two of the multiple streaks are indicated by dotted lines to make the streaks easier to see. From Figs. 8 and 9, it can be seen that the occurrence of moire is suppressed by tilting the extension direction of the band portion BND by 4° with respect to the second direction Y.

[0077] The fact that the extension direction of the band portion BND is inclined at 4° with respect to the second direction Y means that the triangle formed by the band portion BND is not an isosceles triangle. FIG. 9 shows a case where the band portion BND is an isosceles triangle.

[0078] 10 to 13 are simulation results showing the occurrence of moire when the pitch of the band portion is changed and when the stretching direction of the band portion is changed. In FIG. 10, the pitch of the band portion BND is 133.2 μm, and the stretching direction of the band portion BND is inclined by 4° with respect to the second direction Y. In FIG. 11, FIG. 12, and FIG. 13, the pitch of the band portion BND is 133.2 μm, 192 μm, and 360 μm, respectively. In FIG. 11 to FIG. 13, the stretching direction of the band portion BND is parallel to the second direction Y.

[0079] Comparing Fig. 10 and Fig. 11, white bright spots or white streaks are visible in Fig. 11, but such streaks are not observed in Fig. 10. That is, Fig. 10 and Fig. 11 show that when the extension direction of the band portion BND is inclined with respect to the second direction Y, the occurrence of white streaks (moiré) is suppressed.

[0080] 11 to 13, wide streaks extending in a direction roughly parallel to the first direction X are visible in Fig. 13. Comparing Fig. 11 and Fig. 12, diagonally extending white streaks are formed at regular intervals in Fig. 12. The white streaks shown in Fig. 12 are more clearly visible than the white streaks shown in Fig. 11.

[0081] As shown in Figures 10 to 13, the occurrence of white streaks (moire) in Figure 10 is suppressed more than in Figures 11 to 13. That is, it is shown that the pitch of the band portion BND of 133.2 μm and the extension direction inclined by 4° from the second direction Y are effective in suppressing moire.

[0082] The display device DSP of the present invention includes a display panel PNL and a light guide element LG. The light guide element LG has a transparent layer LRI with a low refractive index. The transparent layer LRI has a plurality of strip parts BND. Each of the strip parts BND is formed in a triangular shape that is not an isosceles triangle.

[0083] The extension direction of the imaginary line ES passing through a point HP, which is the center point of the side TH, which is the base of the band portion BND, and a point CP, which is the apex of the band portion BND, is set as the extension direction of the band portion BND. It is preferable that the extension direction of the band portion BND is inclined by 4° with respect to the second direction Y.

[0084] The extending direction of the signal lines SL is parallel to the second direction Y. Therefore, it can be said that the extending direction of the band portion BND is inclined by 4 degrees with respect to the extending direction of the signal lines SL.

[0085] The pitch of the strips BND is preferably different from the pitch of the signal lines SL, and more preferably is smaller than the pitch of the signal lines SL.

[0086] The pitch of the strip portions BND is, for example, 133.2 μm. The pitch of the signal lines SL is, for example, 360 μm. The pitch of the scanning lines GL is, for example, 360 μm. Therefore, the pitch of the pixels PX in each of the first direction X and the second direction Y is, for example, 360 μm.

[0087] By providing the strip BND as described above, it is possible to suppress moire occurring between the strip BND and the signal line SL, in other words, between the strip BND and the pixel PX, thereby making it possible to obtain a display device DSP with improved display quality.

[0088] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0089] BA3...substrate, BND...band, CP...point, MS...virtual line, DSP...display device, ES...virtual line, GL...scanning line, HP...point, KS...virtual line, LG...light-guiding element, LP...point, LRI...transparent layer, LT...light, MH...edge, NH...edge, NLR...area, PNL...display panel, PX...pixel, RP...point, SL...signal line, SS1...first side, SS2...second side, SS3...third side, SS4...fourth side, TH...edge.

Claims

1. A display panel including a first substrate, a second substrate, and a liquid crystal layer having a polymer dispersed liquid crystal; A plurality of light emitting elements; A light guide element; Equipped with The first substrate is A first substrate; A plurality of scanning lines provided on the first substrate, extending along a first direction, and arranged side by side along a second direction intersecting the first direction; a plurality of signal lines provided on the first base material, extending along the second direction, and arranged side by side along the first direction; a plurality of switching elements electrically connected to the plurality of scanning lines and the plurality of signal lines; A plurality of pixel electrodes electrically connected to the plurality of switching elements; Equipped with The second substrate is A second substrate; a common electrode facing the plurality of pixel electrodes; Equipped with The light guide element is A third substrate; a transparent layer having a refractive index lower than the refractive index of the third substrate; Equipped with The transparent layer has a plurality of band portions arranged side by side in the first direction, Each of the plurality of band portions has a triangular shape having a first side, a second side, and a third side; The first side is shorter than the second side and the third side, The second side is shorter than the third side, The first side extends along the first direction, an extension direction of a virtual line connecting a first point at the center of the first side and a second point at which the second side and the third side intersect is defined as an extension direction of each of the plurality of band portions; The stretching direction is inclined at 4° with respect to the second direction, A display device, wherein the length of the first side is shorter than the spacing between the plurality of signal lines.

2. The length of the first side is 133.2 μm; The display device according to claim 1 , wherein the signal lines are spaced apart from one another by 360 μm.

3. The display device according to claim 1 , wherein the transparent layer is made of a siloxane-based resin or a fluorine-based resin.

4. 2. The display device according to claim 1, wherein the third substrate has a refractive index of 1.5, and the transparent layer has a refractive index of 1.0 to 1.4.

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