Display device

Abstract

To provide a display device in which deterioration of display quality can be suppressed.SOLUTION: In a display device, each of a plurality of first pixels has a transparent layer, in which a refraction index is smaller than refraction indexes of a first base material and a second base material, and that contacts with a common electrode; each of a plurality of second pixels has a first insulation layer, in which a refraction index is higher than a refraction index of the transparent layer, and that contacts with the common electrode; a distance between the transparent layer and a pixel electrode is defined as a first cell gap and a distance between the first insulation layer and the pixel electrode is defined as a second cell gap; the first cell gap and the second cell gap are the same; and a ratio of the plurality of first pixels to a plurality of pixels decreases from a first end toward a second end.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

[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). In a transparent display device using PDLC, an edge light method in which a light source is arranged at an end of a light guide plate is adopted. However, when the edge light method is used for a PDLC display device, there is a problem that the luminance of the display surface decreases as the distance from the light source increases.

[0003] In order to solve such a problem, a display device has been developed in which a light guide element having a low refractive index transparent layer provided in an isosceles triangle shape is provided on a liquid crystal panel.

[0004] However, a new problem has occurred in that moire occurs between the isosceles triangle-shaped transparent layer and the pixels.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object of the present embodiment is to provide a display device capable of suppressing a decrease in display quality.

Means for Solving the Problems

[0007] A display device according to an embodiment is A display panel comprising a first substrate, a second substrate, and a liquid crystal layer having a polymer-dispersed liquid crystal. A plurality of light-emitting elements. Comprising. The first substrate is A first base material, A plurality of switching elements, A plurality of pixel electrodes electrically connected to the plurality of switching elements. Comprising. The second substrate is A second base material having a first end adjacent to the light-emitting element and a second end spaced apart from the light-emitting element. A common electrode facing the plurality of pixel electrodes. Comprising. The display panel includes a plurality of pixels including a plurality of first pixels and a plurality of second pixels. Each of the plurality of first pixels has a transparent layer with a refractive index smaller than that of the first base material and the second base material and in contact with the common electrode. Each of the plurality of second pixels has a first insulating layer with a refractive index higher than that of the transparent layer and in contact with the common electrode. Let the distance between the transparent layer and the pixel electrode be the first cell gap, and the distance between the first insulating layer and the pixel electrode be the second cell gap. The first cell gap and the second cell gap are the same. The ratio of the plurality of first pixels to the plurality of pixels decreases from the first end to the second end.

Brief Description of the Drawings

[0008]

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[0009] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. It should be noted that 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. In addition, 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 this is merely an example and does not limit the interpretation of the present invention. Further, in this specification and each figure, elements that are the same as those described above with respect to the already shown figures may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] The embodiments described in this specification are not general, but are embodiments that describe the same or corresponding special technical features of the present invention. Hereinafter, a display device according to an embodiment will be described in detail with reference to the drawings.

[0011] In this embodiment, the first direction X, the second direction Y, and the third direction Z are orthogonal 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. Note that the first direction X, the second direction Y, and the third direction Z may also be referred to as the X direction, the Y direction, and the Z direction, respectively.

[0012] Also, when referring to "the second member above the first member" and "the 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 member and the second member. On the other hand, when referring to "the second member on the first member" and "the second member under the first member", the second member is in contact with the first member.

[0013] Also, it is assumed that there is an observation position for observing the display device on the tip side of the arrow of the third direction Z, and viewing from this observation position toward the X-Y plane defined by the first direction X and the second direction Y is referred to as a plan view. Viewing the cross section of the display device in the X-Z plane defined by the first direction X and the third direction Z, or in the Y-Z plane defined by the second direction Y and the third direction Z, is referred to as a cross-sectional view.

[0014] [Embodiment] FIG. 1 is a plan view showing a schematic configuration of a display device according to an embodiment. In this embodiment, as an example of the display device DSP, a liquid crystal display device applying polymer-dispersed liquid crystal will be described. 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 a flat plate shape parallel to the X-Y plane. The substrates SUB1 and SUB2 overlap in plan view. The substrates SUB1 and SUB2 are adhered by the seal SAL. The liquid crystal layer LC is held between the substrate SUB1 and the substrate SUB2 and is sealed by the seal SAL.

[0016] As schematically shown enlarged in FIG. 1, the liquid crystal layer LC includes a polymer dispersed liquid crystal containing a polymer PLM and liquid crystal molecules LCM. In one example, the polymer PLM is a liquid crystalline polymer. The polymer PLM is formed in a streak shape extending along the first direction X. The liquid crystal molecules LCM are dispersed in the gaps of the polymer PLM and are oriented such that their major axes are 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 that of the liquid crystal molecules LCM to an electric field.

[0017] In one example, the orientation direction of the polymer PLM hardly changes regardless of the presence or absence of an electric field. On the other hand, the orientation direction of the liquid crystal molecules LCM changes in response to an electric field when a voltage 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 the light incident on the liquid crystal layer LC is transmitted through the liquid crystal layer LC with little scattering (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 the light incident on the liquid crystal layer LC is scattered within the liquid crystal layer LC (scattering 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] As shown enlarged in FIG. 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 constituted by, for example, a thin film transistor (TFT) and is electrically connected to a scanning line GL and a signal line SL.

[0020] The plurality of scanning lines GL extend along the first direction X and are arranged side by side along the second direction Y. One scanning line GL is electrically connected to the switching element SW in each of the pixels PX arranged along the first direction X.

[0021] The plurality of signal lines SL extend along a direction parallel to the second direction Y and are arranged side by side along the first direction X. One signal line SL is electrically connected to the switching element SW in each of the pixels PX arranged along the second direction Y. The signal line SL intersects the scanning line GL.

[0022] Each of the plurality of pixels PX occupies a region defined by two adjacent signal lines SL and two adjacent scanning lines GL. That is, the plurality of 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 electrode PE is electrically connected to the switching element SW. Each of the pixel electrodes PE faces the common electrode CE and drives the liquid crystal layer LC (in particular, the liquid crystal molecules LCM) by the electric field generated between the pixel electrode PE and the common electrode CE.

[0024] The scanning line GL, the signal line SL, the switching element SW, and the pixel electrode PE are provided on the substrate SUB1. 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.

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

[0026] In the example shown in FIG. 1, in a plan view, the ends E12 and E22, the ends E13 and E23, and the ends E14 and E24 overlap each other, but they do not necessarily 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 ends E11 and E21.

[0027] The IC chip ICP and the wiring board FPC1 are each connected to the extension area Ex. The IC chip ICP incorporates, for example, a display driver that outputs signals necessary for image display. The wiring board FPC1 is a flexible printed circuit board that can be bent. Note that the IC chip ICP may be connected to the wiring board FPC1. The IC chip ICP and the wiring board FPC1 may read signals from the display panel PNL, but mainly function as signal sources that supply 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. 1. The substrate SUB1 includes a base material BA1, an insulating layer INS1, an insulating layer INS2, a capacitive electrode CSE, a switching element SW, a pixel electrode PE, and an alignment film AL1. The substrate SUB1 further includes a scanning line GL and a signal line SL shown in FIG. 1.

[0029] The base material BA1 is formed of a light-transmissive material. The base material BA1 includes a main surface (lower surface) B1A and a main surface (upper surface) B1B on the opposite side of 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 capacitive 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 the opening OP of the capacitive electrode CSE. The pixel electrode PE overlaps with the capacitive electrode CSE with the insulating layer INS2 therebetween, forming the 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, and a transparent layer LRI.

[0032] The base material BA2 is formed of a light-transmissive material. The base material BA2 includes a main surface (lower surface) B2A and a main surface (upper surface) B2B on the opposite side of the main surface B2A. The main surface B2A of the base material BA2 faces the main surface B1B 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 a plurality of pixels PX and directly covers the light-shielding layer BM. The common electrode CE faces the pixel electrode PE. The common electrode CE is electrically connected to the capacitive electrode CSE and has the same potential as the capacitive electrode CSE. Note that the common electrode CE may be provided for each of the plurality of pixels PX.

[0034] A transparent layer LRI is provided in contact with the common electrode CE. Details of the transparent layer LRI will be described later.

[0035] The alignment film AL2 covers the transparent layer LRI and the common electrode CE. The liquid crystal layer LC is located between the main surface B1B and the main surface B2A and is in contact with the alignment film AL1 and the alignment film AL2.

[0036] The base materials BA1 and BA2 are insulating base materials such as glass and plastic. The main surfaces B1A, B1B, B2A, and B2B are surfaces that are substantially parallel to the X-Y plane.

[0037] The insulating layer INS1 is formed of a transparent insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or an acrylic resin. 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.

[0038] The capacitive 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).

[0039] 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 (Mo), aluminum (Al), tungsten (W), titanium (Ti), or silver (Ag).

[0040] 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-treated along the first direction X. Note that the alignment treatment may be a rubbing treatment or an optical alignment treatment.

[0041] Figure 3 is an exploded perspective view showing the main part of the display device. The display device DSP includes, in addition to the display panel PNL, a plurality of light-emitting elements LD and a base material BA3. The substrate SUB1, the substrate SUB2, and the base material BA3 are arranged in this order along the third direction Z. Note that in Figure 3, the base material BA3 is shown separated from the base material BA2, but as shown in Figure 4 described later, the base material BA3 is arranged in contact with the base material BA2.

[0042] The plurality of light-emitting elements LD are arranged at intervals in the first direction X. The plurality of light-emitting elements LD are connected to the wiring substrate FPC2. The light-emitting element LD is, for example, a light-emitting diode. The light-emitting element LD includes, although not detailed, a red light-emitting element, a green light-emitting element, and a blue light-emitting element. The light emitted from the light-emitting element LD travels along the direction of the arrow indicating the second direction Y.

[0043] The base material BA3 is formed of a light-transmissive material. 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 not a laminate of a plurality of base materials but a single base material.

[0044] The base material BA3 includes a main surface (lower surface) B3A, a main surface (upper surface) B3B on the opposite side of 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 surface B3A and the main surface B3B are surfaces substantially parallel to the X-Y plane. The main surface B3A faces the main surface B2B of the base material BA2.

[0045] 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 the first side surface SS1.

[0046] The plurality of light-emitting elements LD are provided facing the end portion E21 of the substrate SUB2. The plurality of light-emitting elements LD may be provided facing the first side surface SS1 of the base material BA3. In the example shown in FIG. 3, the first side surface SS1 is located directly above the end portion E21 of the substrate SUB2, but may be located directly above the extension region Ex or may be located further outside the end portion E11.

[0047] The base material BA3 is formed of, for example, glass or an organic material such as polymethyl methacrylate (PMMA) or polycarbonate (PC).

[0048] In the display area DA, the area near the light-emitting element LD is defined as area CR, and the area separated from the light-emitting element LD is defined as area FR.

[0049] FIG. 4 is a diagram showing a cross-sectional configuration of a schematic configuration of the display device according to the embodiment. In FIG. 4, among the components of the display panel PNL shown in FIG. 2 and the display device DSP shown in FIG. 3, only the elements necessary for the description are shown.

[0050] As shown in FIG. 4, a transparent layer LRI is provided in contact with the common electrode CE. The density of the transparent layer LRI changes according to the distance from the light-emitting element LD. Specifically, the closer to the light-emitting element LD, the larger the number of pixels PX provided with the transparent layer LRI. As a result, in the region CR close to the light-emitting element LD, the amount of light LT reflected by the transparent layer LRI becomes larger than the amount of light LT incident on the liquid crystal layer LC.

[0051] On the other hand, as described above, in the region FR far from the light-emitting element LD, the area of the transparent layer LRI becomes smaller. As a result, in the region far from the light-emitting element LD, the amount of light LT incident on the display panel PNL is larger than the amount of light LT reflected by the transparent layer LRI.

[0052] Let the refractive index of the base material BA1, the refractive index of the base material BA2, and the refractive index of the base material BA3 be the refractive index n1, the refractive index n2, and the refractive index n3, respectively. Let the refractive index of the transparent layer LRI be the refractive index n4. The refractive index n4 is lower than the refractive index n1, the refractive index n2, and the refractive index n3 (n4 < n1, n2, n3). Note that the refractive index n1, the refractive index n2, and the refractive index n3 may be the same (n1 = n2 = n3). That is, n4 < n1 = n2 = n3 may be satisfied.

[0053] The transparent layer LRI is formed of an organic material such as a siloxane resin or a fluororesin. For example, the refractive index n3 of the base material BA3 is about 1.5, and the refractive index n4 of the transparent layer LRI is about 1.0 to 1.4. When the refractive index n1, the refractive index n2, and the refractive index n3 are the same, the refractive index n1 of the base material BA1 and the refractive index n2 of the base material BA2 are also about 1.5.

[0054] FIG. 5 is a diagram showing a cross-sectional configuration of a schematic configuration of the display device of Comparative Example 1. In the display device DSPr1 shown in FIG. 5, the transparent layer LRI is provided outside, not inside, the display panel PNL. Specifically, the transparent layer LRI is provided between the base materials BA2 and BA3 of the display panel PNL. The light-emitting element LD is provided adjacent to the first side surface SS1 of the base material BA3.

[0055] 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 guides light 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.

[0056] As described above, the light LT is reflected by the main surface B3B and the transparent layer LRI. However, when passing through the region NLR where the transparent layer LRI is not provided on the main surface B3A, it enters the display panel PNL through the region NLR. Note that the light LT may also enter the display panel PNL through the transparent layer LRI.

[0057] By reflecting at 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 facing the first side surface SS1. The light LT 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. Thereby, an image is displayed on the display device DSP.

[0058] Returning to FIG. 4, in the display device DSP in which the transparent layer LRI is provided inside the display panel PNL, more specifically, inside the pixel PX, the light emitted from the light-emitting element LD and incident on the display device DSP is guided toward the fourth side surface SS4 while being reflected by the transparent layer LRI.

[0059] As described above, by controlling the area occupied by the transparent layer LRI in the pixel PX, it is possible to control the aperture ratio. However, in the region where the transparent layer LRI is provided and the region where the transparent layer LRI is not provided within the pixel PX, a cell gap difference occurs in the display panel PNL. When a cell gap difference occurs in the display panel PNL, the display quality of the display device DSP deteriorates.

[0060] FIG. 6 is a diagram showing a cross-sectional configuration of a schematic configuration of the display device of Comparative Example 2. In FIG. 6, a cross-sectional configuration of one pixel PX of the display device DSPr2 of Comparative Example 2 is shown. In the display device DSPr2, there are a region where the transparent layer LRI is provided and a region where the transparent layer LRI is not provided within the pixel PX as shown in FIG. 5. Similar to the display device DSP shown in FIG. 4, the transparent layer LRI is provided within the display panel PNL.

[0061] The display device DSPr2 has a substrate SUB1, a substrate SUB2, and a liquid crystal layer LC. The substrate SUB1 includes a base material BA1, a scanning line GL, an insulating layer INS2, a capacitive electrode CSE, a light-shielding layer LS, and a pixel electrode PE.

[0062] The scanning line GL provided on the base material BA1 is covered with an insulating layer INS1. The upper surface USI1 of the insulating layer INS1 is a flattened surface. The capacitive electrode CSE and the light-shielding layer LS are provided in contact with the upper surface USI1 of the insulating layer INS1.

[0063] An insulating layer INS2 is provided covering the insulating layer INS1, the capacitive electrode CSE, and the light-shielding layer LS. A pixel electrode PE is provided in contact with the insulating layer INS2. On the upper surface USI1 of the insulating layer INS1, the flattened upper surface USI2 of the insulating layer INS2 is disposed.

[0064] The substrate SUB2 has a base material BA2, a light-shielding layer BM, a common electrode CE, a transparent layer LRI, and an insulating layer CRC1.

[0065] The light-shielding layer BM provided on the base material BA2 faces the scanning line GL. The common electrode CE is provided to cover the base material BA2 and the light-shielding layer BM. The transparent layer LRI is provided in contact with a partial region of the common electrode CE. The insulating layer CRC1 is provided to cover the transparent layer LRI and the common electrode CE.

[0066] Similar to the insulating layer INS1, the insulating layer CRC1 is formed of a transparent insulating material such as silicon oxide, silicon nitride, silicon oxynitride, or an acrylic resin. In one example, the insulating layer CRC1 includes an inorganic insulating layer and an organic insulating layer. The refractive index of the insulating layer CRC1 is higher than that of the transparent layer LRI. By providing the insulating layer CRC1, peeling of the transparent layer LRI can be suppressed.

[0067] A spacer PS is disposed between the upper surface USI2 of the insulating layer INS2 and the insulating layer CRC1. The spacer PS has a function of maintaining the distance (cell gap) between the substrate SUB1 and the substrate SUB2. The spacer PS may be formed of, for example, a photosensitive resin material.

[0068] Let the thickness of the transparent layer LRI be tr. Let the distance between the pixel electrode PE and the insulating layer CRC1, and the distance between the pixel electrode PE and the transparent layer LRI be the cell gap gp. Let the cell gap in the region YR where the transparent layer LRI is provided be the cell gap gp1, and the cell gap in the region NR where the transparent layer LRI is not provided be the cell gap gp2.

[0069] The cell gap gp2 is longer than the cell gap gp1 by the thickness tr of the transparent layer LRI. The thickness tr, the cell gap gp1, and the cell gap gp2 may be, for example, 1 μm, 3 μm, and not less than 3.5 μm and not more than 4.0 μm, respectively.

[0070] As described above, the difference between the cell gap gp2 and the cell gap gp1 is, for example, 0.5 μm or more and 1.0 μm or less. If a difference in the cell gap occurs within the pixel PX, the effective electric field strength will be different. Therefore, even if the same voltage is applied between the pixel electrode PE and the common electrode CE, the electric field strengths in the region YR and the region NR will be different. In this case, the luminances of the region YR and the region NR will be different, and the display quality of the display device DSPr2 may deteriorate.

[0071] In the display device of this embodiment, as shown in FIG. 4, the pixel PXL provided with the transparent layer LRI and the pixel PXN not provided with the transparent layer LRI are arranged in the display region DA. In the region CR close to the light-emitting element LD, the ratio of the pixel PXL is increased, and in the region FR separated from the light-emitting element LD, the ratio of the pixel PXN is increased. In the pixel PXN, an insulating layer CRC1 having the same thickness as the transparent layer LRI is formed. Thereby, it is possible to change the area of the transparent layer LRI while keeping the cell gap constant over the display region DA.

[0072] FIG. 7 is a plan view showing the arrangement of pixels in a region close to the light-emitting element. FIG. 8 is a plan view showing the arrangement of pixels in a region separated from the light-emitting element.

[0073] In the region CR shown in FIG. 7, the number of pixels PXL provided with the transparent layer LRI is larger than the number of pixels PXN not provided with the transparent layer LRI. For example, in the region CR shown in FIG. 7, out of 100 pixels PX, the number of pixels PXL is 90, and the number of pixels PXN is 10. In other words, the ratio of the pixel PXL is 90%, and the ratio of the pixel PXN is 10%.

[0074] On the other hand, in the region FR shown in FIG. 8, the number of pixels PXL provided with the transparent layer LRI is smaller than the number of pixels PXN not provided with the transparent layer LRI. For example, in the region FR shown in FIG. 8, out of 100 pixels PX, the number of pixels PXL is 20, and the number of pixels PXN is 80. In other words, the ratio of the pixel PXL is 20%, and the ratio of the pixel PXN is 80%.

[0075] In regions CR and FR, among pixels PXL and PXN, it is preferable that the pixel PX with the smaller number is uniformly arranged. That is, in region CR, it is preferable that pixels PXN are dispersed and scattered. Or, it is preferable that pixels PXN are arranged at a certain interval from each other. Similarly, in region FR, it is preferable that pixels PXL are dispersed and scattered. Or, it is preferable that pixels PXL are arranged at a certain interval from each other. This is because if the pixel PX with the smaller number among pixels PXL and PXN is locally concentrated, the arranged part will be easily visible, resulting in a decrease in display quality.

[0076] As the distance from the light-emitting element LD increases, the number of pixels PXL decreases and the number of pixels PXN increases. At this time, it is preferable that the number of pixels PXL decreases stepwise. If the number of pixels PXL decreases rapidly, the luminance will also change rapidly, which is also a cause of the decrease in display quality.

[0077] FIG. 9 is a cross-sectional view of a schematic example of pixel PXL. FIG. 10 is a cross-sectional view of a schematic example of pixel PXN. Regarding FIGS. 9 and 10, the substrate SUB1 has the same configuration as that in FIG. 6.

[0078] In pixel PXL, on substrate SUB2, a transparent layer LRI is provided in contact with the common electrode CE, but the insulating layer CRC1 is not provided (see FIG. 9). On the other hand, in pixel PXN, on substrate SUB2, an insulating layer CRC1 is provided in contact with the common electrode CE, but the transparent layer LRI is not provided (see FIG. 10). Note that it is preferable that the area of the region where the transparent layer LRI is provided in pixel PXL and the area of the region where the insulating layer CRC1 is provided in pixel PXN are the same.

[0079] It is preferable that the thickness of the transparent layer LRI provided in pixel PXL and the thickness of the insulating layer CRC1 provided in pixel PXN are the same.

[0080] In pixel PXL, the distance between the transparent layer LRI and the pixel electrode PE is defined as cell gap gpa. In pixel PXN, the distance between the insulating layer CRC1 and the pixel electrode PE is defined as cell gap gpb. The cell gap gpa and the cell gap gpb are the same.

[0081] Since the cell gap gpa and the cell gap gpb are the same, the electric field strengths in pixels PXL and PXN are constant. Therefore, it is possible to suppress a decrease in the display quality of the display device DSP.

[0082] In the configuration examples shown in FIGS. 9 and 10, a new insulating layer may be provided in contact with the transparent layer LRI and the insulating layer CRC1. FIG. 11 is a cross-sectional view of another schematic example of pixel PXL. FIG. 12 is a cross-sectional view of another schematic example of pixel PXN. The configuration examples shown in FIGS. 11 and 12 are different from the configuration examples shown in FIGS. 9 and 10 in that an insulating layer CRC2 is provided in contact with the transparent layer LRI and the insulating layer CRC1.

[0083] In FIG. 11, the insulating layer CRC2 is formed to cover the transparent layer LRI. By providing the insulating layer CRC2 to cover the transparent layer LRI, it is possible to suppress the transparent layer LRI from peeling off from the common electrode CE, further promote the planarization of the substrate SUB2, and set the cell gap gpc and the cell gap gpd, which will be described later, to be the same.

[0084] In the pixel PXL shown in FIG. 11, the distance between the insulating layer CRC2 and the pixel electrode PE is defined as cell gap gpc. In the pixel PXN shown in FIG. 12, the distance between the insulating layer CRC2 and the pixel electrode PE is defined as cell gap gpd. The cell gap gpc and the cell gap gpd are the same.

[0085] In the pixel PXL, in addition to the transparent layer LRI, an insulating layer CRC2 is provided. Accordingly, for the pixel PXN as well, an insulating layer CRC2 is provided in addition to the insulating layer CRC1. The insulating layer CRC2 provided in the pixel PXL and the pixel PXN needs to have the same thickness. Thereby, the cell gap gpc of the pixel PXL and the cell gap gpc of the pixel PXN can be made the same. Therefore, similar to FIGS. 9 and 10, in the display device DSP having the pixels shown in FIGS. 11 and 12 as well, it is possible to suppress a decrease in the display quality of the display device DSP.

[0086] The insulating layer CRC2 may be formed of the material used for the above-described insulating layer CRC1. The insulating layer CRC2 may be formed of the same material as the insulating layer CRC1 or may be formed of a different material. When the insulating layer CRC1 and the insulating layer CRC2 are of the same material, the insulating layer CRC1 and the insulating layer CRC2 of the pixel PXN may be integrally formed.

[0087] FIG. 13 is a cross-sectional view showing an example of a schematic configuration example of a display device. In the display device DSP shown in FIG. 13, only the components necessary for the description are shown, and other components are omitted.

[0088] In FIG. 13, the display area DA of the display device DSP is divided into, for example, 11 regions from the end portion E21 to the end portion E24 of the substrate SUB2. That is, the display area DA is divided into 11 regions from the side adjacent to the light-emitting element LD toward the side farthest from the light-emitting element LD. It can be said that the display area DA includes a region RR1, a region RR2, a region RR3, a region RR4, a region RR5, a region RR6, a region RR7, a region RR8, a region RR9, a region RR10, and a region RR11 from the side adjacent to the light-emitting element LD.

[0089] Let the aperture ratios of region RR1, region RR2, region RR3, region RR4, region RR5, region RR6, region RR7, region RR8, region RR9, region RR10, and region RR11 be aperture ratio OR1, aperture ratio OR2, aperture ratio OR3, aperture ratio OR4, aperture ratio OR5, aperture ratio OR6, aperture ratio OR7, aperture ratio OR8, aperture ratio OR9, aperture ratio OR10, and aperture ratio OR11, respectively.

[0090] When not distinguishing regions RR1 to RR11, they are simply called region RR. When not distinguishing aperture ratios OR1 to OR11, they are simply called aperture ratio OR. The number of regions RR is not limited to 11. The larger the number of regions RR, the smoother the change in aperture ratio OR. When the change in aperture ratio OR becomes smoother, the display quality improves. However, due to manufacturing constraints such as manufacturing costs, the number of regions RR may be limited. The number of regions RR may be appropriately determined in view of display quality and manufacturing constraints.

[0091] Aperture ratios OR1 to OR11 are, respectively, the ratios of the regions where the transparent layer LRI is not provided in regions RR1 to RR11. In other words, it can also be said to be the ratio of pixel PXN to all pixels PX. Aperture ratio OR may be the number of pixels PXN to the total number of all pixels PX in region RR. It may also be the area occupied by pixel PXN to the area occupied by all pixels PX in region RR.

[0092] As described above, it is desirable that aperture ratios OR1 to OR11 change smoothly. Ideally, aperture ratio OR preferably increases continuously. However, if it is difficult to increase continuously in manufacturing, it may be increased step by step.

[0093] Let the overall length of the display area DA along the direction parallel to the second direction Y be length dd. Let the lengths of region RR1, region RR2, region RR3, region RR4, region RR5, region RR6, region RR7, region RR8, region RR9, region RR10, and region RR11 along the direction parallel to the second direction Y be length dr1, length dr2, length dr3, length dr4, length dr5, length dr6, length dr7, length dr8, length dr9, length dr10, and length dr11, respectively.

[0094] For example, when aperture ratios OR1, OR2, OR3, OR4, OR5, OR6, OR7, OR8, OR9, OR10, and OR11 are 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% respectively, the ratios of length dr1, length dr2, length dr3, length dr4, length dr5, length dr6, length dr7, length dr8, length dr9, length dr10, and length dr11 to length dd can be 5%, 10%, 10%, 10%, 10%, 10%, 10%, 10%, 10%, 10%, and 5% respectively. That is, the lengths of region RR1 and region RR11 are 5% of the total length dd, and the lengths of region RR2 to region RR10 are 10% of the total length dd.

[0095] For example, the aperture ratio OR2 of region RR2 is 10%. The pixels PXL and PXN of region RR2 may be arranged as described in FIG. 7. Similarly, for example, the aperture ratio OR9 of region RR9 is 80%. The pixels PXL and PXN of region RR9 may be arranged as described in FIG. 8.

[0096] Also, in adjacent regions RR, among the pixels PXL and PXN, it is preferable that the pixels PX with the smaller number are dispersed and scattered with respect to each other. This is because if the pixels PX with the smaller number are locally concentrated and arranged at the boundary of adjacent regions RR, the arranged part is likely to be visually recognized, resulting in a decrease in display quality.

[0097] The display device DSP of this embodiment reduces the ratio occupied by the transparent layer LRI from the side adjacent to the light-emitting element LD toward the side spaced apart. As a result, in the region close to the light-emitting element LD, the ratio of the light LT from the light-emitting element LD reflected by the transparent layer LRI increases, and the light LT propagates toward the side spaced apart from the light-emitting element LD. On the side spaced apart from the light-emitting element LD, since the ratio occupied by the transparent layer LRI is small, the ratio of the light LT incident into the pixel PX increases. Thereby, the light LT becomes uniform over the display area DA.

[0098] In the pixel PXN where the transparent layer LRI is not provided, an insulating layer CRC1 is provided instead of the transparent layer LRI. Thereby, the cell gaps of the pixel PXL where the transparent layer LRI is provided and the pixel PXN where the transparent layer LRI is not provided become uniform. Thereby, a decrease in display quality can be suppressed.

[0099] <Configuration Example 1> FIG. 14 is a cross-sectional view showing an example of another configuration of the display panel of the embodiment. The display panel PNL shown in FIG. 14 is different in that the transparent layer LRI is provided in the same layer as the light-shielding layer BM as compared with the display panel PNL shown in FIG. 2.

[0100] The transparent layer LRI is disposed on the main surface B2A, similarly to the light-shielding layer BM. The common electrode CE is provided to cover the transparent layer LRI and the light-shielding layer BM. The alignment film AL2 is provided to cover the common electrode CE. Also in this configuration example, the same effects as those of the embodiment are achieved.

[0101] <Configuration Example 2> FIG. 15 is a cross-sectional view showing an example of another configuration of the display panel of the embodiment. The display panel PNL shown in FIG. 15 is different in that the transparent layer LRI is provided between the pixel electrode PE and the alignment film AL2 as compared with the display panel PNL shown in FIG. 2.

[0102] In FIG. 15, a transparent layer LRI is provided in contact with the pixel electrode PE. The alignment layer AL1 is provided so as to cover the pixel electrode PE, the transparent layer LRI, and the insulating layer INS2. Further, the transparent layer LRI is not limited to this example, and may be provided, for example, between the alignment layer AL1 and the alignment layer AL2. Also in this configuration example, the same effects as those of the embodiment are obtained.

[0103] 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, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0104] BA1... substrate, BA2... substrate, BA3... substrate, CR... region, CRC1... insulating layer, CRC2... insulating layer, DA... display region, DSP... display device, FR... region, LC... liquid crystal layer, LD... light emitting element, LRI... transparent layer, LT... light, NLR... region, NR... region, OR... aperture ratio, PNL... display panel, PX... pixel, PXL... pixel, PXN... pixel, RR... region, YR... region, gp... cell gap.

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; Equipped with The first substrate is A first substrate; A plurality of switching elements; A plurality of pixel electrodes electrically connected to the plurality of switching elements; Equipped with The second substrate is a second substrate having a first end adjacent the light emitting element and a second end spaced from the light emitting element; a common electrode facing the plurality of pixel electrodes; Equipped with the display panel includes a plurality of pixels including a plurality of first pixels and a plurality of second pixels; each of the first pixels has a transparent layer having a refractive index smaller than that of the first substrate and the second substrate and in contact with the common electrode; Each of the second pixels includes a first insulating layer having a refractive index higher than that of the transparent layer and in contact with the common electrode; a distance between the transparent layer and the pixel electrode is a first cell gap, and a distance between the first insulating layer and the pixel electrode is a second cell gap; the first cell gap and the second cell gap are the same; A display device, wherein a ratio of the first pixels to the pixels decreases from the first end to the second end.

2. The display device of claim 1 , wherein the number of the first pixels decreases from the first end to the second end.

3. The display device according to claim 1 , wherein areas of the first pixels decrease from the first end to the second end.

4. The display device according to claim 1 , further comprising a second insulating layer in contact with the transparent layer and the first insulating layer, the second insulating layer having a refractive index higher than that of the transparent layer.

5. The display device according to claim 1 , further comprising a third substrate having the same refractive index as the first substrate and the second substrate and in contact with the second substrate.

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

7. The display device according to claim 1 , wherein the first and second substrates have a refractive index of 1.5, and the transparent layer has a refractive index of 1.0 to 1.

4.

8. The display device according to claim 5 , wherein the third substrate has a refractive index of 1.

5.

9. The first substrate is 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; The display device according to claim 1 , further comprising: a plurality of switching elements electrically connected to the plurality of scanning lines and the plurality of signal lines.

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