Display device

Abstract

To provide a display device capable of improving display quality.SOLUTION: According to an embodiment, a display device includes a light source, a prism sheet configured to split illumination light from the light source into transmitted light and refracted light, a liquid crystal panel configured to be illuminated by the transmitted light and the refracted light and to display an image, a diffusion sheet located between the prism sheet and the liquid crystal panel, a first polarizer located between the diffusion sheet and the liquid crystal panel, and a second polarizer sandwiching the liquid crystal panel with the first polarizer. When a polarization component that vibrates parallel to a plane defined by the first normal line and the second normal line is p-polarized light and a polarization component that vibrates perpendicular to the plane is s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light, and the second polarizer has a second transmission axis perpendicular to the first transmission axis.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A technology is known for a display device mounted on a vehicle that displays two images on a single screen and splits the images into one image and the other image. One image can be viewed by looking directly at the screen, while the other image can be viewed as an image projected onto the windshield or the like. In such display devices, there is a demand for improvement in display quality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-259043 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-216794 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the embodiment is to provide a display device that can improve display quality. [Means for solving the problem]

[0005] According to an embodiment, the display device comprises: a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel configured to be illuminated by the transmitted light and the refracted light and to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet positioned between the prism sheet and the liquid crystal panel; a first polarizer positioned between the diffusion sheet and the liquid crystal panel; and a second polarizer sandwiching the liquid crystal panel between the diffusion sheet and the liquid crystal panel, wherein a first normal to the light source's emission surface and a second normal to the liquid crystal panel intersect at an acute angle, and when a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light, and the second polarizer has a second transmission axis perpendicular to the first transmission axis.

[0006] According to an embodiment, the display device comprises: a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel configured to be illuminated by the transmitted light and the refracted light and to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet located between the prism sheet and the liquid crystal panel; a first polarizer located between the diffusion sheet and the liquid crystal panel; a second polarizer sandwiching the liquid crystal panel between the diffusion sheet and the first polarizer; and a retardation plate which is a λ / 2 plate. a first normal to the light output surface of the light source and a second normal to the liquid crystal panel intersect at an acute angle; when a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light; the second polarizer has a second transmission axis perpendicular to the first transmission axis and is located between the liquid crystal panel and the retardation plate; and the retardation plate has an extension axis that intersects with the second transmission axis at an acute angle.

[0007] According to an embodiment, the display device comprises: a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel configured to be illuminated by the transmitted light and the refracted light and to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet located between the prism sheet and the liquid crystal panel; a first polarizer located between the diffusion sheet and the liquid crystal panel; a second polarizer sandwiching the liquid crystal panel between the diffusion sheet and the first polarizer; and a retardation plate which is a λ / 4 plate; a first normal to the exit surface of the light source and a second normal to the liquid crystal panel intersect at an acute angle; when a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light; the second polarizer has a second transmission axis perpendicular to the first transmission axis and is located between the liquid crystal panel and the second polarizer; and the retardation plate has an extension axis that intersects with the second transmission axis at an acute angle. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a display device DSP. [Figure 2] FIG. 2 is an enlarged view of the prism sheet PS and the diffusion sheet DS of the display device DSP shown in FIG. [Figure 3] FIG. 3 is a diagram showing the simulation results of the relationship between the angle θ1 and the transmittance T. [Figure 4] FIG. 4 is a diagram for explaining the polarizer PL1 and the polarizer PL2 applied to the display device DSP shown in FIG. [Figure 5] FIG. 5 is a diagram for explaining the display light DL1 and the display light DL2 in the display device DSP shown in FIG. [Figure 6] FIG. 6 is a diagram showing another example of the configuration of the display device DSP. [Figure 7]FIG. 7 is a diagram illustrating an example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG. [Figure 8] FIG. 8 is a diagram illustrating another example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG. [Figure 9] FIG. 9 is a diagram illustrating another example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. The disclosure is merely an example, and appropriate modifications that a person skilled in the art can easily make while maintaining the gist of the disclosure are naturally included within the scope of the present disclosure. Furthermore, in the drawings, the width, thickness, shape, etc. of each part may be schematically depicted compared to the actual embodiment for clarity of explanation, but these are merely examples and are not intended to limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, components that perform the same or similar functions as those described above with respect to the previous drawings are designated by the same reference numerals, and redundant detailed descriptions may be omitted as appropriate.

[0010] In addition, to facilitate understanding, the drawings depict, where necessary, mutually perpendicular X, Y, and Z axes. 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. Viewing various elements parallel to the third direction Z is referred to as a planar view. Note that terms referring to the relative positions of two or more components, such as above, above, between, and facing, include not only cases where the two or more components are in direct contact, but also cases where they are separated from each other by a gap or another component.

[0011] FIG. 1 is a diagram showing an example of the configuration of a display device DSP.

[0012] The display device DSP includes an illumination device IL, a liquid crystal panel PNL, a polarizer PL1, and a polarizer PL2. The illumination device IL includes a light source LS, an optical system OS, a prism sheet PS, and a diffusion sheet DS.

[0013] The light source LS is, for example, a light-emitting diode and has a substantially flat emission surface ES. The light source LS is configured to emit illumination light L0 from the emission surface ES. The illumination light L0 emitted from the light source LS travels along a normal N1 to the emission surface ES.

[0014] The optical system OS is located between the light source LS and the prism sheet PS. The optical system OS includes at least one lens and is configured to collimate the divergent illumination light L0 emitted from the light source LS.

[0015] The prism sheet PS is located between the optical system OS and the diffusion sheet DS. The prism sheet PS is configured to split the illumination light L0 into transmitted light L1 and refracted light L2. Although not described in detail, the prism sheet PS may have, for example, multiple prisms on the side facing the optical system OS. In such a prism sheet PS, a portion of the illumination light L0 passes through adjacent prisms and becomes transmitted light L1, while another portion of the illumination light L0 is refracted by each prism and becomes refracted light L2. The transmitted light L1 travels along a normal N1. The refracted light L2 travels in a direction different from the normal N1 depending on the shape of the prism.

[0016] The liquid crystal panel PNL is illuminated by the transmitted light L1 and the refracted light L2, and is configured to display a first image based on the transmitted light L1 and a second image based on the refracted light L2. The first image and the second image are different from each other. For example, on the liquid crystal panel PNL, pixels in an area illuminated by the transmitted light L1 are driven by a video signal corresponding to the first image, and pixels in an area illuminated by the refracted light L2 are driven by a video signal corresponding to the second image.

[0017] Such a liquid crystal panel PNL is disposed so as to be inclined with respect to the normal line N1. The normal line N1 to the exit surface ES and the normal line N2 to the liquid crystal panel PNL intersect at an acute angle θ1.

[0018] The diffusion sheet DS is located between the prism sheet PS and the liquid crystal panel PNL. The diffusion sheet DS is configured to diffuse the transmitted light L1 and the refracted light L2. Such a diffusion sheet DS may be, for example, an isotropic diffusion sheet or an anisotropic diffusion sheet.

[0019] Each of the prism sheet PS and the diffusion sheet DS is disposed substantially parallel to the liquid crystal panel PNL, and is inclined with respect to the normal line N1, similar to the liquid crystal panel PNL.

[0020] The polarizer PL1 is located between the diffusion sheet DS and the liquid crystal panel PNL and has a transmission axis T1.

[0021] The polarizer PL2 is located between the user U and the liquid crystal panel PNL and is disposed so as to display the liquid crystal panel PNL between itself and the polarizer PL1. That is, the liquid crystal panel PNL is located between the polarizer PL1 and the polarizer PL2. The polarizer PL2 has a transmission axis T2 perpendicular to the transmission axis T1. For example, each of the polarizers PL1 and PL2 is bonded to the liquid crystal panel PNL.

[0022] Here, the plane defined by normal line N1 and normal line N2 is called the N1-N2 plane. Also, the polarization component oscillating parallel to the N1-N2 plane is called p-polarized light PP, and the polarization component oscillating perpendicular to the N1-N2 plane is called s-polarized light SP. The transmission axis T1 is parallel to the N1-N2 plane, so the polarizer PL1 is configured to transmit p-polarized light PP and absorb s-polarized light SP.

[0023] Illumination light L0 emitted from light source LS is unpolarized and contains p-polarized light PP and s-polarized light SP. The illumination light L0 is split into transmitted light L1 and refracted light L2 by prism sheet PS, and then illuminates liquid crystal panel PNL. The transmitted light L1 forms a first image on the liquid crystal panel PNL. The refracted light L2 forms a second image on the liquid crystal panel PNL.

[0024] The display light DL1 that forms the first image is projected onto a screen (for example, a windshield or combiner of a vehicle) SC and is visible to the user U. The display light DL2 that forms the second image is directly visible to the user U.

[0025] Next, the reason why the transmission axis T1 is parallel to the N1-N2 plane will be explained.

[0026] FIG. 2 is an enlarged view of the prism sheet PS and the diffusion sheet DS of the display device DSP shown in FIG.

[0027] The prism sheet PS has a surface S1, shown by a dashed line, facing the light source LS, and a surface S2, shown by a dashed line, facing the diffusion sheet DS. The diffusion sheet DS has a surface S3, shown by a dashed line, facing the prism sheet PS, and a surface S4, shown by a dashed line, facing the polarizer PL1. These surfaces S1, S2, S3, and S4 are in contact with air and can serve as interfaces that reflect light.

[0028] As described with reference to Figure 1, the prism sheet PS and the diffusion sheet DS are disposed substantially parallel to the liquid crystal panel PNL. Therefore, the normal N2 of the liquid crystal panel PNL is substantially parallel to the normals of the surfaces S1 and S2 of the prism sheet PS. The normal N2 is also substantially parallel to the normals of the surfaces S3 and S4 of the diffusion sheet DS. In other words, the normals of the prism sheet PS and the diffusion sheet DS are inclined at an angle θ1 with respect to the normal N1.

[0029] When illumination light L0 emitted from light source LS travels along normal line N1, a portion of the illumination light L0 is reflected by each of surfaces S1, S2, S3, and S4. This reflected light does not contribute to display and is lost. Therefore, if the reflectance of these four surfaces is high, this will result in a decrease in the brightness of display light DL1, particularly light traveling along normal line N1.

[0030] 1 is mounted on a vehicle, the angle θ1 tends to be set larger in order to suppress undesired reflection of external light incident through the windshield on the display device DSP. If the angle θ1 is large, the reflectance of each of the above four surfaces will further increase, which may be a factor in further reducing the brightness of the display light DL1.

[0031] FIG. 3 is a diagram showing the simulation results of the relationship between the angle θ1 and the transmittance T.

[0032] The horizontal axis of the diagram is the angle θ1 (°) shown in FIG. 2, and the vertical axis of the diagram is the normalized transmittance T when the maximum transmittance is set to 1.

[0033] When the illumination light L0 shown in Figure 2 is s-polarized, the transmittance decreases as the angle θ1 increases, as shown by the dashed line in the figure. In other words, the reflectance of s-polarized light increases as the angle θ1 increases.

[0034] On the other hand, when the illumination light L0 shown in Figure 2 is p-polarized light, as shown by the solid line in the figure, the transmittance increases as the angle θ1 increases from 0°, reaches a maximum when the angle θ1 is approximately 60°, and decreases as the angle θ1 increases further from 60°. In other words, when the angle θ1 is approximately 60°, the reflectance of p-polarized light is minimum. In particular, when the angle θ1 is in the range of 35° to 70°, the reflectance of p-polarized light is 90% or more.

[0035] Thus, when comparing p-polarized light and s-polarized light, it can be seen that the difference in transmittance is significant when the angle θ1 is greater than 30° and less than 75°. Furthermore, when the angle θ1 is set to greater than 45° as a measure against external light, it can be seen that the transmittance of p-polarized light is extremely high and the reflectance of s-polarized light is extremely high. In other words, one of the causes of a decrease in the brightness of the display light when the angle θ1 is large is the increase in the reflectance of s-polarized light. For this reason, in this embodiment, the display device DSP actively utilizes p-polarized light from the illumination light L0 to obtain display light with high brightness.

[0036] FIG. 4 is a diagram for explaining the polarizer PL1 and the polarizer PL2 applied to the display device DSP shown in FIG.

[0037] Here, the direction parallel to the s-polarized light SP is defined as the first direction X, the direction parallel to the p-polarized light PP is defined as the second direction Y, and the direction of light propagation is defined as the third direction Z. The third direction Z is parallel to the normal N2 of the liquid crystal panel PNL shown in Figure 1 etc. The YZ plane defined by the second direction Y and the third direction Z is parallel to the N1-N2 plane shown in Figure 1.

[0038] In the polarizer PL1, the transmission axis T1 is parallel to the second direction Y, and the absorption axis A1 is parallel to the first direction X. Therefore, the polarizer PL1 transmits p-polarized light PP and absorbs s-polarized light SP. In the polarizer PL2, the transmission axis T2 is in a crossed Nicol relationship with the transmission axis T1 and is parallel to the first direction X. The absorption axis A2 is parallel to the second direction Y.

[0039] FIG. 5 is a diagram for explaining the display light DL1 and the display light DL2 in the display device DSP shown in FIG.

[0040] The illumination light L0 emitted from the light source LS, and the transmitted light L1 and refracted light L2 split by the prism sheet PS are all unpolarized and contain p-polarized light PP and s-polarized light SP. Of the transmitted light L1 and refracted light L2, the p-polarized light PP passes through the polarizer PL1 and illuminates the liquid crystal panel PNL. Of the transmitted light L1 and refracted light L2, the s-polarized light SP is absorbed by the polarizer PL1.

[0041] The p-polarized light PP incident on the liquid crystal panel PNL is modulated appropriately for each pixel. A portion of the light transmitted through the liquid crystal panel PNL passes through the polarizer PL2 to form display light DL1 and display light DL2. As shown in FIG. 4, since the transmission axis T2 of the polarizer PL2 is parallel to the first direction X, the display light DL1 and display light DL2 are linearly polarized light parallel to the first direction X. The user U can view both the display light DL1 and display light DL2.

[0042] In this display device DSP, a polarizer PL1 configured to transmit p-polarized light is applied to the liquid crystal panel PNL, which is tilted with respect to the normal N1 of the exit surface ES of the light source LS, and the liquid crystal panel PNL is illuminated with p-polarized light. In other words, by using p-polarized light, which has little reflection loss in the prism sheet PS and the diffusion sheet DS, high-brightness display light DL1 and display light DL2 can be obtained. Therefore, display quality can be improved compared to when a polarizer PL1 configured to transmit s-polarized light is applied.

[0043] Furthermore, in a display device DSP mounted on a vehicle, even if the angle θ1 is set to 60° or more, high-brightness display light DL1 and display light DL2 can be obtained, and deterioration of display quality due to external light entering through the windshield is suppressed.

[0044] The inventors calculated the luminance of the display light DL1 by simulation for an example in which the polarizer PL1 is set to transmit p-polarized light and a comparative example in which the polarizer PL1 is set to transmit s-polarized light.

[0045] In the embodiment, the transmission axis T1 of the polarizer PL1 is set in the second direction Y, and the transmission axis T2 of the polarizer PL2 is set in the first direction X. In the comparative example, the transmission axis T1 of the polarizer PL1 is set in the first direction X, and the transmission axis T2 of the polarizer PL2 is set in the second direction Y.

[0046] It was confirmed that when the angle θ1 was 30°, the luminance of the display light DL1 in the example was increased by approximately 20% compared to the comparative example. It was confirmed that when the angle θ1 was 60°, the luminance of the display light DL1 in the example was increased by approximately 85% compared to the comparative example.

[0047] Next, a case where the user U views the display device DSP while wearing polarized sunglasses will be described.

[0048] FIG. 6 is a diagram showing another example of the configuration of the display device DSP.

[0049] The configuration example shown in FIG. 6 differs from the configuration example shown in FIG. 1 in that the display device DSP further includes a retardation plate RT. The retardation plate RT is located between the polarizer PL2 and the user U. The polarizer PL2 is located between the liquid crystal panel PNL and the retardation plate RT. In one example, one main surface of the retardation plate RT is bonded onto a base film, and the other main surface of the retardation plate RT is bonded to the polarizer PL2. The retardation plate RT is a λ / 2 plate that imparts a phase difference of λ / 2 wavelength to light of a predetermined wavelength, or a λ / 4 plate that imparts a phase difference of λ / 4 wavelength to light of a predetermined wavelength.

[0050] Other elements that are the same as those in the configuration example shown in FIG. 1 are given the same reference numerals, and duplicated explanations will be omitted.

[0051] FIG. 7 is a diagram illustrating an example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG.

[0052] In the polarizer PL1, the transmission axis T1 is parallel to the second direction Y, and the absorption axis A1 is parallel to the first direction X. Therefore, the polarizer PL1 transmits p-polarized light PP and absorbs s-polarized light SP. In the polarizer PL2, the transmission axis T2 is parallel to the first direction X, and the absorption axis A2 is parallel to the second direction Y. The retardation plate RT is a λ / 2 plate and has an extension axis AX. The extension axis AX intersects with the transmission axis T2 at an acute angle. In the illustrated example, the angle θ2 between the transmission axis T2 and the extension axis AX is 45°.

[0053] Polarized sunglasses are generally configured to absorb s-polarized light, meaning that the absorption axis A3 of the polarized sunglasses is set horizontally and is parallel to the first direction X as shown in the figure.

[0054] The display light DL1 and display light DL2 that have passed through the polarizer PL2 are linearly polarized light parallel to the first direction X, but when they pass through the retardation plate RT, the vibration plane of the light rotates by 90°, and they are converted into linearly polarized light parallel to the second direction Y. In other words, the display light DL1 and display light DL2 that have passed through the retardation plate RT are linearly polarized light that is perpendicular to the absorption axis A3 of the polarized sunglasses, and are hardly absorbed by the polarized sunglasses. Therefore, a user U wearing the polarized sunglasses can see the high-brightness display light DL1 and display light DL2.

[0055] FIG. 8 is a diagram illustrating another example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG.

[0056] The example shown in Fig. 8 differs from the example shown in Fig. 7 in that the angle θ2 between the transmission axis T2 and the stretching axis AX is 22.5°. The retardation plate RT is a λ / 2 plate.

[0057] The display light DL1 and display light DL2 that have passed through the polarizer PL2 are linearly polarized light parallel to the first direction X, but when they pass through the retardation plate RT, the vibration plane rotates by 45° and they are converted into linearly polarized light that intersects both the first direction X and the second direction Y. In other words, the display light DL1 and display light DL2 that have passed through the retardation plate RT are linearly polarized light that intersects the absorption axis A3 of the polarized sunglasses at 45°. Therefore, a user U wearing the polarized sunglasses can see the display light DL1 and display light DL2.

[0058] FIG. 9 is a diagram illustrating another example of the polarizer PL1, the polarizer PL2, and the retardation plate RT that are applied to the display device DSP shown in FIG.

[0059] The example shown in FIG. 9 differs from the example shown in FIG. 7 in that the retardation plate RT is a λ / 4 plate, and the angle θ2 between the transmission axis T2 and the stretching axis AX is 45°.

[0060] The display light DL1 and the display light DL2 that have passed through the polarizer PL2 are linearly polarized light parallel to the first direction X, but are further converted into circularly polarized light when passing through the retardation plate RT. Therefore, a user U wearing the polarized sunglasses can see the display light DL1 and the display light DL2.

[0061] In the above embodiment, for example, polarizer PL1 corresponds to the first polarizer, and the transmission axis T1 corresponds to the first transmission axis, polarizer PL2 corresponds to the second polarizer, and the transmission axis T2 corresponds to the second transmission axis. Normal N1 corresponds to the first normal, and normal N2 corresponds to the second normal. Surface S1 corresponds to the first surface, surface S2 corresponds to the second surface, surface S3 corresponds to the third surface, and surface S4 corresponds to the fourth surface.

[0062] According to the embodiment described above, it is possible to provide a display device capable of improving display quality.

[0063] Although several embodiments of the present disclosure have been described, these embodiments are presented as examples and are not intended to limit the scope of the disclosure. 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 disclosure. These embodiments and their modifications are included within the scope and spirit of the disclosure, as well as within the scope of the disclosure and its equivalents as set forth in the claims. [Explanation of symbols]

[0064] DSP...Display device PNL...Liquid crystal panel IL...Lighting device LS...Light source OS...Optical system PS...Prism sheet DS...Diffusion sheet PL1…Polarizing photon T1…Through axis PL2…Polarizing T2…Through axis RT…phase difference plate AX…extension shaft

Claims

1. a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel illuminated by the transmitted light and the refracted light, and configured to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet positioned between the prism sheet and the liquid crystal panel; a first polarizer positioned between the diffusion sheet and the liquid crystal panel; a second polarizer sandwiching the liquid crystal panel between the first polarizer and the second polarizer, a first normal to the light source's emission surface and a second normal to the liquid crystal panel intersect at an acute angle; When a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light, and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light; the second polarizer has a second transmission axis perpendicular to the first transmission axis; Display device.

2. Further, a retardation plate is provided, the second polarizer is located between the liquid crystal panel and the retardation plate, the retarder has an extension axis that intersects with the second transmission axis at an acute angle; The display device according to claim 1 .

3. the retardation plate is a λ / 2 plate, The angle between the second transmission axis and the stretching axis is 45°. The display device according to claim 2 .

4. the retardation plate is a λ / 2 plate, The angle between the second transmission axis and the stretching axis is 22.5°. The display device according to claim 2 .

5. the retardation plate is a λ / 4 plate, The angle between the second transmission axis and the stretching axis is 45°. The display device according to claim 2 .

6. a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel illuminated by the transmitted light and the refracted light, and configured to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet positioned between the prism sheet and the liquid crystal panel; a first polarizer positioned between the diffusion sheet and the liquid crystal panel; a second polarizer sandwiching the liquid crystal panel between the first polarizer and the second polarizer; a retardation plate which is a λ / 2 plate, a first normal to the light source's emission surface and a second normal to the liquid crystal panel intersect at an acute angle; When a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light, and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light; the second polarizer has a second transmission axis perpendicular to the first transmission axis and is located between the liquid crystal panel and the retardation plate; the retarder has an extension axis that intersects with the second transmission axis at an acute angle; Display device.

7. a light source configured to emit illumination light; a prism sheet configured to split the illumination light from the light source into transmitted light and refracted light; a liquid crystal panel illuminated by the transmitted light and the refracted light, and configured to display a first image based on the transmitted light and a second image based on the refracted light; a diffusion sheet positioned between the prism sheet and the liquid crystal panel; a first polarizer positioned between the diffusion sheet and the liquid crystal panel; a second polarizer sandwiching the liquid crystal panel between the first polarizer and the second polarizer; a retardation plate which is a λ / 4 plate, a first normal to the light source's emission surface and a second normal to the liquid crystal panel intersect at an acute angle; When a polarization component vibrating parallel to a plane defined by the first normal and the second normal is defined as p-polarized light, and a polarization component vibrating perpendicular to the plane is defined as s-polarized light, the first polarizer has a first transmission axis parallel to the plane and is configured to transmit the p-polarized light and absorb the s-polarized light; the second polarizer has a second transmission axis perpendicular to the first transmission axis and is located between the liquid crystal panel and the second polarizer; the retarder has an extension axis that intersects with the second transmission axis at an acute angle; Display device.

8. The angle between the first normal and the second normal is 30° or more and 75° or less.

8. The display device according to claim 1, 6, or 7.

9. the prism sheet has a first surface facing the light source and a second surface facing the diffusion sheet, the diffusion sheet has a third surface facing the prism sheet and a fourth surface facing the first polarizer, the first surface, the second surface, the third surface, and the fourth surface are in contact with air; 8. The display device according to claim 1, 6, or 7.

Images