Display device

Abstract

To provide a display device which can surely secure a wider range of a viewing angle in which an image cannot be seen while attaining the range of a viewing angle in which an image can be seen and the range of a viewing angle in which an image cannot be seen at the same time.SOLUTION: A display device 1 includes: a display panel 30; a light source 60; and a light adjusting unit 10 capable of changing a degree of transmission of light between the display panel 30 and the light source 60. In the light adjusting unit 10, a first polarization layer 11, a first liquid crystal panel 20A, a second polarization layer 12, a second liquid crystal panel 20B, and a third polarization layer 13 are overlapped in a direction from the light source 60 side to the display panel 30. The first liquid crystal panel 20A is provided as an E-mode liquid crystal panel and a second liquid crystal panel 20B is provided as an O-mode liquid crystal panel.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] In recent years, there is a demand for display devices that are able to change the viewing angle range in which an image can be viewed. For example, in a display device mounted on a vehicle such as a four-wheeled automobile, it is required to realize a viewing angle range in which an image can be viewed from the passenger seat, and the image cannot be viewed from the driver's seat only while driving. In order to realize such a viewing angle range, a technology has been proposed in which a liquid crystal panel for dimming that can switch the viewing angle range is superimposed on a panel for displaying an image (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-195388 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the display device described in Patent Document 1, the viewing angle at which the image becomes so dark that it becomes impossible to view due to the liquid crystal panel for dimming is limited to a very narrow specific viewing angle. Therefore, the image may be visible in a viewing angle range outside the specific viewing angle. Therefore, there has been a demand for a display device that can simultaneously establish a viewing angle range in which the image is visible and a viewing angle range in which the image is not visible, while ensuring a wider and more reliable viewing angle range in which the image is not visible.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a display device that can simultaneously establish a viewing angle range in which an image can be viewed and a viewing angle range in which an image cannot be viewed, while ensuring a wider and more reliable viewing angle range in which an image cannot be viewed. [Means for solving the problem]

[0006] A display device according to one embodiment of the present disclosure comprises a display panel having a display area for outputting an image, a light source for irradiating light from one side of the display panel, and a dimming unit interposed between the display panel and the light source and configured to change the degree of light transmission between the display panel and the light source, wherein the dimming unit has a first polarizing layer, a first liquid crystal panel, a second polarizing layer, a second liquid crystal panel, and a third polarizing layer overlapping from the light source side toward the display panel side, one of the first liquid crystal panel and the second liquid crystal panel being configured as an E-mode liquid crystal panel, and the other of the first liquid crystal panel and the second liquid crystal panel being configured as an O-mode liquid crystal panel. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram showing an example of a main configuration of a display device according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of each of the components of the display device. [Diagram 3] FIG. 3 is a diagram showing changes in the deflection direction of light that occur from the light source until it is emitted to the other surface side of the display device. [Figure 4] FIG. 4 is a diagram showing the relationship between the rubbing directions R6a, R6b of the alignment films of the second liquid crystal panel and the transmission axis directions of the second polarizing layer and the third polarizing layer arranged to face each other in the third direction across the second liquid crystal panel. [Diagram 5] FIG. 5 is a diagram showing the orientation of liquid crystal molecules when the liquid crystal panel is not in operation (OFF). [Figure 6] FIG. 6 is a diagram showing the orientation of liquid crystal molecules when the liquid crystal panel is in operation (ON). [Figure 7] FIG. 7 is a diagram showing an example of the viewing angle characteristics of a display device caused by the degree of light transmission when the liquid crystal panel is in operation (ON). [Figure 8]FIG. 8 is a schematic diagram showing an example of the relationship between a display device, a user who can view an image regardless of whether the liquid crystal panel is operating / not operating (ON / OFF), and a user who cannot view an image when the liquid crystal panel is operating (ON). [Figure 9] FIG. 9 is a schematic diagram showing the difference between an image viewed by a user looking at the display device from the front and an image viewed by a user looking at the display device obliquely. [Figure 10] FIG. 10 is a graph showing the relationship between the polar angle and the light transmittance when the liquid crystal panel is in operation (ON) for each of the E mode and the O mode. [Figure 11] FIG. 11 is a graph showing the normalized transmittance of a display device in the second state for each of the E mode only, the O mode only, and a combination of the E mode and the O mode. [Figure 12] FIG. 12 is a graph showing the normalized transmittance of a display device in the second state for each of the E mode only, the O mode only, and a combination of the E mode and the O mode. [Figure 13] FIG. 13 is a plan view showing an example of a pixel layout in a display panel. [Figure 14] FIG. 14 is a graph showing the relationship between the polar angle and the light transmittance when a liquid crystal panel used as an E-mode liquid crystal panel is operating (ON) when the twist angle is 90° (twist 90°) and when the twist angle is 80° (twist 80°). [Figure 15] FIG. 15 is a graph showing the normalized transmittance on one side and the other side in the first direction when a liquid crystal panel provided as an E-mode liquid crystal panel is operating (ON) when the twist angle is 90° (twist 90°) and when the twist angle is 80° (twist 80°). [Figure 16] FIG. 16 is a graph showing the normalized transmittance on one side and the other side in the first direction when a liquid crystal panel provided as an E-mode liquid crystal panel is operating (ON) when the twist angle is 90° (twist 90°) and when the twist angle is 80° (twist 80°). [Figure 17]FIG. 17 is a graph showing the normalized transmittance on one side and the other side in the first direction when a liquid crystal panel provided as an O-mode liquid crystal panel is operating (ON) when the twist angle is 90° (twist 90°) and when the twist angle is 80° (twist 80°). [Figure 18] Figure 18 is a graph showing the normalized transmittance on one side and the other side in the first direction when a liquid crystal panel provided as an O-mode liquid crystal panel is operating (ON) when the twist angle is 90° (twist 90°) and when the twist angle is 80° (twist 80°). [Figure 19] FIG. 19 is a schematic diagram showing an example of a main configuration of a display device according to the second modification. [Figure 20] FIG. 20 is a schematic diagram showing an example of a polarization angle of the polarized light generating layer that can be employed in the second modification, and an angle range in which the polarization angle can be set. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, each embodiment of the present disclosure 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 are naturally included in the scope of the present disclosure. In addition, in order to make the explanation clearer, the drawings may be schematic in terms of the width, thickness, shape, etc. of each part compared to the actual embodiment, but they are merely examples and do not limit the interpretation of the present disclosure. 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.

[0009] (Embodiment) FIG. 1 is a schematic diagram showing a main configuration example of a display device 1 according to an embodiment. The display device 1 includes a light control unit 10, a display panel 30, a light source 60, a retardation generating layer 51, and a retardation generating layer 52. The direction in which the light control unit 10, the display panel 30, the light source 60, the retardation generating layer 51, and the retardation generating layer 52 overlap is defined as a third direction Z. In addition, one of two directions perpendicular to the third direction Z is defined as a first direction X, and the other is defined as a second direction Y. The first direction X and the second direction Y are perpendicular to each other. In the display device 1, the light source 60, the retardation generating layer 51, the light control unit 10, the retardation generating layer 52, and the display panel 30 overlap in this order from one side to the other side of the third direction Z.

[0010] Fig. 2 is a schematic cross-sectional view of each of the components of the display device 1. In Fig. 2, there are gaps between the components of the light source 60, the retardation generating layer 51, the light control section 10, the retardation generating layer 52, and the display panel 30. The gaps are provided for the purpose of making the drawing easier to understand, and are not necessary in the actual display device 1 (see Fig. 1).

[0011] The light control unit 10 is configured such that a first polarizing layer 11, a first liquid crystal panel 20A, a second polarizing layer 12, a second liquid crystal panel 20B, and a third polarizing layer 13 are overlapped from one side to the other side in the third direction Z. The first polarizing layer 11, the second polarizing layer 12, and the third polarizing layer 13, as well as a fourth polarizing layer 41 and a fifth polarizing layer 42 described later, are optical members provided to transmit polarized light in a specific direction most. The specific direction is referred to as a transmission axis direction. The transmission axis direction is along the polarizing plate. In other words, the transmission axis direction is perpendicular to the third direction Z. The direction perpendicular to the transmission axis direction and the third direction Z is referred to as an absorption axis direction. The absorption axis direction is a polarization direction in which light is least likely to transmit through the polarizing plate.

[0012] The first liquid crystal panel 20A and the second liquid crystal panel 20B are liquid crystal panels. The first liquid crystal panel 20A and the second liquid crystal panel 20B have the same configuration as a device, except that they are provided at different positions. Hereinafter, when the liquid crystal panel 20 is described, it includes the first liquid crystal panel 20A and the second liquid crystal panel 20B. In other words, the description of the liquid crystal panel 20 can be commonly applied to the first liquid crystal panel 20A and the second liquid crystal panel 20B. The liquid crystal panel 20 of the embodiment is a so-called TN (Twisted Nematic) type liquid crystal panel.

[0013] The liquid crystal panel 20 has a configuration in which a first substrate 21 is provided on one side of the liquid crystal LM, and a second substrate 22 is provided on the other side. The first substrate 21 and the second substrate 22 are light-transmitting substrates. The light-transmitting substrate is, for example, a glass substrate, but is not limited thereto, and may be a substrate made of other light-transmitting materials. Hereinafter, when "one side" is described, it refers to a surface on one side in the third direction Z in a plate-like configuration. Furthermore, when "the other side" is described, it refers to a surface on the other side in the third direction Z in a plate-like configuration.

[0014] A first electrode FE1 is formed on the other surface of the first substrate 21. A second electrode FE2 is formed on one surface of the second substrate 22. The first electrode FE1 and the second electrode FE2 are electrodes provided to cover the display area AA. The other surface of the first electrode FE1 and the other surface of the first substrate 21 in an area where the first electrode FE1 is not formed are covered with an insulating layer 23. One surface of the second electrode FE2 and the one surface of the second substrate 22 in an area where the second electrode FE2 is not formed are covered with an insulating layer 24. The display area AA will be described later.

[0015] At least one of the first electrode FE1 and the second electrode FE2 is provided so that the potential can be changed depending on the ON / OFF state of the liquid crystal panel 20. That is, the voltage generated between the first electrode FE1 and the second electrode FE2 differs between when the liquid crystal panel 20 is operating (ON) and when it is not operating (OFF).

[0016] Between the insulating layer 23 and the insulating layer 24, at least in the display area AA, liquid crystal LM is interposed. In addition, outside the display area AA, a seal 25 is interposed between the insulating layer 23 and the insulating layer 24. Although not shown, the seal 25 is a frame-shaped member that surrounds the liquid crystal LM when viewed from the front on a plane (XY plane) perpendicular to the third direction Z. The liquid crystal LM is enclosed by the seal 25 between the insulating layer 23 and the insulating layer 24, and is thereby sealed in the liquid crystal panel 20.

[0017] An alignment film 23a is provided on the other surface of the insulating layer 23 in an area that covers at least the display area AA. An alignment film 24a is provided on one surface of the insulating layer 24 in an area that covers at least the display area AA. The alignment films 23a and 24a orient the liquid crystal molecules contained in the liquid crystal LM in a specific direction. The alignment of the liquid crystal molecules changes when the potential difference between the first electrode FE1 and the second electrode FE2 changes.

[0018] The display panel 30 is a liquid crystal panel different from the liquid crystal panel 20. The display panel 30 has a plurality of pixels. The display panel 30 is a liquid crystal panel for displaying images that is provided so that the degree of light transmission at each position of the plurality of pixels can be individually controlled in response to input of image data from the outside.

[0019] The display panel 30 shown in Fig. 2 is a so-called IPS (In Plane Switching) type liquid crystal panel. In the display panel 30, a pixel substrate 31 is provided on one side in the third direction Z with liquid crystal LQ sandwiched therebetween, and a counter substrate 32 is provided on the other side. Furthermore, a fourth polarizing layer 41 is provided on one surface side of the pixel substrate 31. A fifth polarizing layer 42 is provided on the other surface side of the counter substrate 32. Hereinafter, when the term "panel section DP" is used, it refers to the portion of the display panel 30 excluding the fourth polarizing layer 41 and the fifth polarizing layer 42.

[0020] On the other surface of the pixel substrate 31, a common electrode CE, an insulating layer 33, a pixel electrode P, an insulating layer 34, etc. are laminated from one side to the other side in the third direction Z. On one surface of the counter substrate 32, a color filter 35, etc. are laminated. Outside the display area AA, a seal 36 is interposed between the insulating layer 34 and the color filter 35. The seal 36 has the same shape as the seal 25 described above. The liquid crystal LQ is enclosed in the display panel 30 by being surrounded by the seal 36 between the insulating layer 34 and the color filter 35.

[0021] The display area AA is an area in the display panel 30 where a plurality of pixel electrodes P are arranged. The plurality of pixel electrodes P are arranged two-dimensionally along the XY plane in the display area AA. The display panel 30 is a so-called active matrix type display panel that is provided so as to be capable of displaying and outputting any image by individually controlling the degree of light transmission in each pixel electrode P. More specifically, in the display panel 30 of the embodiment, a reference potential is applied to the common electrode CE. Furthermore, individual potentials (pixel signals) are applied to the plurality of pixel electrodes P, so that the degree of light transmission in each pixel electrode P is individually controlled. Therefore, the display area AA can be said to be an area where an image is displayed and output.

[0022] The retardation generating layer 51 and the retardation generating layer 52 are optical members that change the phase of light entering from one side in the third direction Z and transmit the light to the other side in the third direction Z. The retardation generating layer 51 and the retardation generating layer 52 in the embodiment are so-called 1 / 2 wavelength plates.

[0023] The light source 60 emits light toward the other surface on which the polarized light generating layer 53 is provided. The polarized light generating layer 53 is an optical member that polarizes the light emitted from the other surface of the light source 60 at a specific angle. The polarized light generating layer 53 is, for example, a DBEF (Dual Brightness Enhancement Film), but is not limited thereto, and may be configured to polarize the light emitted from the other surface of the light source 60 at a specific angle. The light generated by the light source 60 passes through the polarized light generating layer 53, the dimming unit 10, the fourth polarizing layer 41, the display panel 30, and the fifth polarizing layer 42 and is emitted to the other surface of the display device 1.

[0024] Next, a change in the deflection direction of light that occurs before the light generated by the light source 60 is emitted to the other surface side of the display device 1 will be described with reference to FIG.

[0025] FIG. 3 is a diagram showing changes in the deflection direction of light that occur before the light generated by the light source 60 is emitted to the other side of the display device 1. In the following description, polarization along the first direction X is defined as 0° polarization. In addition, in the description with reference to FIG. 3, the polarization angle is shown as an acute angle less than 180° with respect to the 0° polarization. In addition, in the description with reference to FIG. 3, among the changes in the deflection direction of light, a change in counterclockwise rotation by r° along the XY plane is described as a "change of +r°", and a change in the opposite (clockwise) rotation by r° is described as a "change of -r°". r is a real number equal to or greater than 0.

[0026] In the embodiment, the polarization axis direction V01 of the polarization generating layer 53 is determined so as to transmit the light emitted from the other surface of the light source 60 as 0° polarized light. Therefore, the polarized light transmitted through the polarization generating layer 53 and incident on the phase difference generating layer 51 is 0° polarized light.

[0027] The retardation generating layer 51 is a half-wave plate as described above. The retardation generating layer 51 of the embodiment generates a change in the counterclockwise (+) direction. The retardation generating layer 51 has a slow axis direction V02 set to be +22.5° with respect to the polarized light (0°) transmitted through the polarized light generating layer 53. As a result, the polarized light is changed by +45° by transmitting through the retardation generating layer 51. Therefore, the polarized light transmitted through the retardation generating layer 51 and incident on the first polarizing layer 11 is polarized at 45°. FIG. 3 shows the angle V02b of the polarized light incident on the retardation generating layer 51 and the angle V02a of the polarized light transmitted through the retardation generating layer 51.

[0028] The first polarizing layer 11 has a transmission axis direction V03 determined so as to transmit the maximum amount of 45° polarized light. Therefore, the light transmitted through the phase difference generation layer 51 can be transmitted through the first polarizing layer 11. Moreover, the polarized light transmitted through the first polarizing layer 11 and incident on the first liquid crystal panel 20A is polarized at 45°.

[0029] The liquid crystal panel 20 is provided so as to give a change of +90° to the polarized light transmitted from one side to the other side in the third direction Z. That is, a change of +90° occurs in the polarized light by transmitting through the first liquid crystal panel 20A. Therefore, the polarized light transmitted through the phase difference generating layer 51 and incident on the first polarizing layer 11 is polarized at 135°. FIG. 3 shows the angle V04b of the polarized light incident on the first liquid crystal panel 20A and the angle V04a of the polarized light transmitted through the first liquid crystal panel 20A.

[0030] The second polarizing layer 12 has a transmission axis direction V05 determined so as to transmit 135° polarized light to the maximum extent possible. Therefore, the light transmitted through the first liquid crystal panel 20A can transmit through the second polarizing layer 12. Moreover, the polarized light that transmits through the second polarizing layer 12 and enters the second liquid crystal panel 20B is polarized at 135°.

[0031] By passing through the second liquid crystal panel 20B, the polarized light changes by +90°. Therefore, the polarized light passing through the phase difference generating layer 51 and entering the first polarizing layer 11 can be said to be polarized at 225°, which is the same as the polarized light at 45°. FIG. 3 shows the angle V06b of the polarized light entering the second liquid crystal panel 20B and the angle V046 of the polarized light passing through the second liquid crystal panel 20B.

[0032] The third polarizing layer 13 has a transmission axis direction V07 determined so as to transmit the maximum amount of 45° polarized light. Therefore, the light transmitted through the second liquid crystal panel 20B can be transmitted through the third polarizing layer 13. Moreover, the polarized light transmitted through the third polarizing layer 13 and incident on the phase difference generating layer 52 is polarized at 45°.

[0033] The retardation generating layer 52 is a half-wave plate as described above. The retardation generating layer 52 of the embodiment generates a change in the clockwise (-) direction. The retardation generating layer 52 has a slow axis direction V08 set to be -22.5° with respect to the polarized light (45°) transmitted through the polarized light generating layer 53. As a result, the polarized light is changed by -45° when it passes through the retardation generating layer 52. Therefore, the polarized light that passes through the retardation generating layer 52 and enters the fourth polarizing layer 41 is polarized at 0°. FIG. 3 shows the angle V08b of the polarized light that enters the retardation generating layer 52 and the angle V08a of the polarized light that has passed through the retardation generating layer 52.

[0034] The fourth polarizing layer 41 has a transmission axis direction V09 determined so as to transmit 0° polarized light to the maximum extent. Therefore, the light transmitted through the phase difference generation layer 52 can be transmitted through the fourth polarizing layer 41. Moreover, the polarized light transmitted through the fourth polarizing layer 41 and incident on the panel unit DP is 0° polarized light.

[0035] The panel part DP is provided so as to impart a change of +90° to the polarized light transmitted from one side to the other side in the third direction Z. That is, a change of +90° occurs in the polarized light as it passes through the panel part DP. Therefore, the polarized light that passes through the panel part DP and enters the fifth polarizing layer 42 is polarized at 90°. FIG. 3 shows an angle V10b of the polarized light that enters the panel part DP and an angle V10a of the polarized light that has passed through the panel part DP.

[0036] The fifth polarizing layer 42 has a transmission axis direction V11 determined so as to transmit a maximum amount of 90° polarized light. Therefore, the light transmitted through the panel unit DP can transmit through the fifth polarizing layer 42. In this manner, a light transmission path LV from the light source 60 to the other surface side of the fifth polarizing layer 42 is established.

[0037] Next, the liquid crystal panel 20 will be described in more detail with reference to FIGS.

[0038] 4 is a diagram showing the relationship between the rubbing directions R6a, R6b of the alignment films 23a, 24a of the second liquid crystal panel 20B and the transmission axis directions of the second polarizing layer 12 and the third polarizing layer 13 arranged to face each other in the third direction Z across the second liquid crystal panel 20B. In the description with reference to FIG. 4 and FIG. 7 described later, the direction toward one side of the first direction X (the right in FIG. 4) is defined as the 0° direction. The direction that forms an angle counterclockwise with respect to the 0° direction is defined as the plus (+) angle (°) direction, and the direction that forms an angle clockwise is defined as the minus (-) angle (°) direction.

[0039] The alignment films 23a and 24a are each subjected to a rubbing treatment on the surface facing the liquid crystal LM in order to orient the liquid crystal molecules in a specific direction. The specific direction determined by the rubbing treatment is the rubbing direction. The rubbing direction R6b of the alignment film 23a is 225° (-135°). The rubbing direction R6a of the alignment film 24a is 315° (-45°).

[0040] In the second liquid crystal panel 20B, one side of the first substrate 21 on which the alignment film 23a is laminated faces the second polarizing layer 12. As shown in Figures 3 and 4, the transmission axis direction V5 of the second polarizing layer 12 is 135°. That is, the rubbing direction R6b of the alignment film 23a and the transmission axis direction V5 of the second polarizing layer 12 are perpendicular to each other.

[0041] In the second liquid crystal panel 20B, the second substrate 22 on which the alignment film 24a is laminated faces the third polarizing layer 13 on the other side. As shown in Figures 3 and 4, the transmission axis direction V7 of the third polarizing layer 13 is 45°. That is, the rubbing direction R6a of the alignment film 24a and the transmission axis direction V7 of the third polarizing layer 13 are perpendicular to each other.

[0042] 4, in the second liquid crystal panel 20B of the embodiment, the rubbing direction of the alignment film laminated on the substrate is perpendicular to the alignment axis of the polarizing layer that abuts on the substrate, i.e., the second liquid crystal panel 20B is provided as a so-called O-mode liquid crystal panel.

[0043] As described above, the first liquid crystal panel 20A and the second liquid crystal panel 20B have a common configuration (liquid crystal panel 20) as liquid crystal panels. Therefore, the rubbing direction R6b of the alignment film 23a on one side of the first liquid crystal panel 20A is 225° (−135°) like the second liquid crystal panel 20B. Here, the transmission axis direction V3 of the first polarizing layer 11 arranged on one side with the first liquid crystal panel 20A sandwiched between them is 45°. The rubbing direction R6a of the alignment film 24a on the other side of the first liquid crystal panel 20A is 315° (−45°) like the second liquid crystal panel 20B. The transmission axis direction V5 of the second polarizing layer 12 arranged on the other side with the first liquid crystal panel 20A sandwiched between them is 135°. From these, in the first liquid crystal panel 20A of the embodiment, the rubbing direction of the alignment film laminated on the substrate and the alignment axis of the polarizing layer abutting the substrate are parallel. That is, the first liquid crystal panel 20A is provided as a so-called E-mode liquid crystal panel.

[0044] More specifically, the liquid crystal molecules contained in the liquid crystal LM can be considered to have an elongated spheroid shape. Here, the long axis direction of the elongated spheroid is defined as ne(n extraordinary ) axis. The short axis direction of the spheroid perpendicular to the ne axis is no(n ordinary ) axis. In the E mode, the rubbing direction of the alignment film 23a is determined so that the transmission axis direction of the polarizing layer facing the alignment film 23a across the first substrate 21 is the same as the ne axis, and the rubbing direction of the alignment film 24a is determined so that the transmission axis direction of the polarizing layer facing the alignment film 24a across the second substrate 22 is the same as the ne axis. In the O mode, the rubbing direction of the alignment film 23a is determined so that the transmission axis direction of the polarizing layer facing the alignment film 23a across the first substrate 21 is the same as the no axis, and the rubbing direction of the alignment film 24a is determined so that the transmission axis direction of the polarizing layer facing the alignment film 24a across the second substrate 22 is the same as the no axis.

[0045] The rubbing direction does not limit the polarized light that is transmitted, that is, the alignment films 23a and 24a transmit light regardless of the rubbing direction.

[0046] The rubbing directions of the alignment films 23a and 24a affect the alignment of the liquid crystal molecules contained in the liquid crystal LM. In FIG. 4 and FIG. 5 and FIG. 6 described later, liquid crystal molecules LM2 are shown as liquid crystal molecules contained in the liquid crystal LM. Among the liquid crystal molecules LM2, those located on the alignment film 23a side and aligned along the rubbing direction R6b are specifically referred to as liquid crystal molecules LMB. Among the liquid crystal molecules LM2, those located on the alignment film 24a side and aligned along the rubbing direction R6a are specifically referred to as liquid crystal molecules LMA. Among the liquid crystal molecules LM2, those located approximately midway between the liquid crystal molecules LMA and LMB in the third direction Z are specifically referred to as liquid crystal molecules LMC.

[0047] 4, when viewed from the front of the XY plane, the liquid crystal molecules LM2 closer to the alignment film 23a exhibit an alignment closer to the rubbing direction R6b, and the liquid crystal molecules LM2 closer to the alignment film 24a exhibit an alignment closer to the rubbing direction R6a. Due to the continuity of the change in alignment of the multiple liquid crystal molecules LM2 aligned in the third direction Z, the liquid crystal panel 20 changes the polarized light passing from one side to the other side in the third direction Z by +90°.

[0048] FIG. 5 is a diagram showing the orientation of the liquid crystal molecules LM2 when the liquid crystal panel 20 is not operating (OFF). FIG. 6 is a diagram showing the orientation of the liquid crystal molecules LM2 when the liquid crystal panel 20 is operating (ON). As described above, the liquid crystal panel 20 is a TN type liquid crystal panel. Therefore, when the liquid crystal panel 20 is not operating (OFF), as shown in FIG. 5, the long axis direction LX of the liquid crystal molecules LM2 is approximately along the XY plane. On the other hand, when the liquid crystal panel 20 is operating (ON), the orientation of the liquid crystal molecules LM2 changes so that the long axis direction LX faces the Z direction side according to the potential difference between the first electrode FE1 and the second electrode FE2 (see FIG. 2). Therefore, when the liquid crystal panel 20 is operating (ON), as shown in FIG. 6, the long axis direction LX of the liquid crystal molecules LM2 intersects the XY plane.

[0049] When the liquid crystal panel 20 is in a non-operating state (OFF) as described with reference to FIG. 5, there is almost no difference in the degree of light transmission between one side in the first direction X and the other side in the first direction X. That is, when the first liquid crystal panel 20A and the liquid crystal panel 20 are both in a non-operating state (OFF), when the image DSP (see FIG. 9) of the display device 1 is viewed from each of two viewpoints that are linearly symmetric in the first direction X with the viewpoint in which the display device 1 is viewed from the front, the brightness of the image recognized at the two viewpoints is almost the same. Hereinafter, when the image DSP is described, it refers to an image displayed and output by the display panel 30 of the display device 1. In addition, at this time, the image can be viewed at a viewpoint in which the display device 1 is viewed from the front with a brightness higher than that of the other viewpoints. That is, when the liquid crystal panel 20 is in a non-operating state (OFF), the degree to which light along the third direction Z transmits through the liquid crystal panel 20 is equal to or higher than the degree to which light intersecting the third direction Z transmits through the liquid crystal panel 20.

[0050] On the other hand, when the liquid crystal panel 20 is in the operation (ON) described with reference to Fig. 6, the degree of light transmission differs between one side in the first direction X and the other side in the first direction X. The viewing angle characteristics of the display device 1 caused by the degree of light transmission when the liquid crystal panel 20 is in the operation (ON) will be described with reference to Fig. 7.

[0051] Fig. 7 is a diagram showing an example of the viewing angle characteristics of the display device 1 caused by the degree of light transmission when the liquid crystal panel 20 is in operation (ON). The center of the concentric circles in Fig. 7 corresponds to the normal line of the display device 1 along the third direction Z, and the concentric circles centered on the normal line indicate that the inclination angles with respect to the normal line are 20°, 40°, 60°, and 80°, respectively. The characteristic diagram shown here was obtained by connecting the regions of equal transmittance for each orientation.

[0052] As shown in Fig. 7, when the line of sight of the user with respect to the display device 1 is inclined toward one side (0°) of the first direction X, a relatively high light transmittance is obtained. Also, when the line of sight of the user with respect to the display device 1 is along the normal direction, that is, when the user looks at the display device 1 from the front, a relatively high light transmittance is obtained. In contrast, when the line of sight of the user with respect to the display device 1 is inclined toward the other side (180°) of the first direction X, the light transmittance becomes significantly lower than that of the one side. In particular, when the inclination angle of the line of sight toward the other side (180°) of the first direction X exceeds 30°, the transmittance becomes 3% or less in the example shown in Fig. 7, and the image becomes so dark that it is practically unrecognizable to humans.

[0053] The viewing angle characteristics as described with reference to Fig. 7 can be used for display output control intended to make an image visible to a user who views the display device 1 from the front or from one side in the first direction X, and to make an image invisible to a user who views the display device 1 from the other side in the first direction X. An example of application of such display output control will be described with reference to Fig. 8.

[0054] FIG. 8 is a schematic diagram showing an example of the relationship between the display device 1, a user U1 who can view the image DSP regardless of whether the liquid crystal panel 20 is operating / non-operating (ON / OFF), and a user U2 who cannot view the image DSP when the liquid crystal panel 20 is operating (ON).

[0055] As shown in FIG. 8, the display device 1 and the user U1 face each other in the third direction Z. Although not shown in FIG. 8, the other side of the display device 1, that is, the fifth polarizing layer 42 side, is the user U1 side in FIG. 8. Therefore, the light LS1 of the image directed to the user U1 in association with the display output by the display device 1 is along the third direction Z. In the case of such a positional relationship between the display device 1 and the user U1, it can be said that the user U1 is at a viewpoint that views the display device 1 from the front. On the other hand, the user U2 is at a position that views the other side of the display device 1 obliquely from a direction inclined toward the other side of the first direction X with respect to the third direction Z. In other words, the light LS2 of the image directed to the user U2 in association with the display output by the display device 1 is inclined toward the other side of the first direction X (180° in FIG. 7). In the case of such a positional relationship between the display device 1 and the user U2, it can be said that the user U2 is at a viewpoint that views the display device 1 obliquely.

[0056] 8, a case where the display device 1 is provided in a four-wheeled vehicle in which the user U2 sits in the driver's seat and the user U1 sits in the passenger seat is assumed, but the case is not limited to this. For example, such a positional relationship may be provided when the display device 1 is provided as a personal monitor for each passenger in an aircraft such as a passenger plane, and other cases may also be included.

[0057] 9 is a schematic diagram showing the difference between the image DSP viewed by a user looking at the display device 1 from the front and a user looking at the display device 1 obliquely. The user looking at the display device 1 from the front is, for example, user U1 in FIG. 8. The user looking at the display device 1 obliquely is, for example, user U2 in FIG. 8. In the explanation with reference to FIG. 9, a state of the display device 1 in which the display panel 30 displays and outputs an image and the liquid crystal panel 20 is not operating (OFF) is defined as a first state. Also, a state of the display device 1 in which the display panel 30 displays and outputs an image and the liquid crystal panel 20 is operating (ON) is defined as a second state.

[0058] As described above, when the liquid crystal panel 20 is not in operation (OFF), the degree to which light along the third direction Z passes through the liquid crystal panel 20 is equal to or greater than the degree to which light intersecting the third direction Z passes through the liquid crystal panel 20. Also, as described with reference to FIG. 7, even when the liquid crystal panel 20 is in operation (ON), a relatively high light transmittance is obtained when the user views the display device 1 from the front. Therefore, the image DSP shown in FIG. 9 can be viewed by a user viewing the display device 1 from the front, regardless of whether the operating state of the display device 1 is the first state or the second state. Note that the aspect of the image DSP shown in FIG. 9 is merely an example and is not limited thereto. The display panel 30 can display and output any image.

[0059] On the other hand, as described with reference to FIG. 7, when the liquid crystal panel 20 is in operation (ON), if the user's line of sight with respect to the display device 1 is tilted toward the other side (180°) of the first direction X, the light transmittance is significantly lower than that of the one side. Therefore, when the operating state of the display device 1 is the second state, a user who views the display device 1 obliquely from the other side of the first direction X cannot substantially view the image DSP. Note that, when the operating state of the display device 1 is the second state, a significant decrease in light transmittance as described with reference to FIG. 7 does not occur even on the other side (180°) of the first direction X. Therefore, when the operating state of the display device 1 is the first state, a user who views the display device 1 obliquely from the other side of the first direction X can view approximately the same image DSP as a user who views the display device 1 from the front.

[0060] As shown in FIG. 9, the image DSP is visually recognized as a rectangular image. That is, when the display device 1 is viewed from the front, the display area AA is a rectangle corresponding to the image DSP shown in FIG. 9. Of the four sides of the rectangle, two sides are along the first direction X, and the other two sides are along the second direction Y. The light control unit 10 of the embodiment makes the degree of light transmission of the ray inclined to one side of the longitudinal direction (first direction X) of the rectangle different from the degree of light transmission of the ray inclined to the other side of the longitudinal direction, based on the third direction Z. As a result, the light control unit 10 generates a visual difference between the first state and the second state described with reference to FIG. 9.

[0061] As described above, the light control unit 10 includes the first liquid crystal panel 20A provided as an E-mode liquid crystal panel and the second liquid crystal panel 20B provided as an O-mode liquid crystal panel. Hereinafter, the optical characteristics resulting from the mixture of the E-mode liquid crystal panel and the O-mode liquid crystal panel will be described with reference to Figs. 10 to 12.

[0062] Fig. 10 is a graph showing the relationship between the polar angle and the light transmittance when the liquid crystal panel 20 is in operation (ON) for each of the E mode and the O mode. The horizontal axis (polar angle) in Fig. 10 and Fig. 14 described later indicates the angle between the reference (0°) of the angle along the third direction Z and the ray of light inclined to the other side of the first direction X in the explanation with reference to Fig. 7 (the 180.0 side in Fig. 7). The vertical axis (transmittance) indicates the light transmittance of the ray corresponding to the polar angle indicated by the horizontal axis.

[0063] As shown in FIG. 10, the relationship between the polar angle and the light transmittance when the liquid crystal panel 20 is in operation (ON) is different between the liquid crystal panel 20 (e.g., the first liquid crystal panel 20A) provided as the liquid crystal panel in the E mode and the liquid crystal panel 20 (e.g., the second liquid crystal panel 20B) provided as the liquid crystal panel in the O mode. Specifically, in the liquid crystal panel 20 provided as the liquid crystal panel in the E mode, the graph showing the relationship between the polar angle and the transmittance is a deep valley-like graph in which the transmittance peaks at a polar angle of 30° and then drops significantly to less than 1%. On the other hand, in the liquid crystal panel 20 provided as the liquid crystal panel in the O mode, the graph showing the relationship between the polar angle and the transmittance is a relatively gentle basin-like graph compared to the E mode, where the transmittance is approximately 1% from a polar angle of 30° to a polar angle of 40°.

[0064] By utilizing the difference in optical characteristics between the E mode and the O mode as described with reference to Fig. 10, it is possible to realize viewing angle characteristics more suitable for suppressing the visibility of the image DSP from the other side in the first direction X for the display device 1 in the second state. Specifically, as described with reference to Figs. 3 and 4, by having one liquid crystal panel 20 (e.g., the first liquid crystal panel 20A) provided as a liquid crystal panel for the E mode and one liquid crystal panel 20 (e.g., the second liquid crystal panel 20B) provided as a liquid crystal panel for the O mode, it is possible to more reliably suppress the visibility of the image DSP from the other side in the first direction X for the display device 1 in the second state.

[0065] 11 and 12 are graphs showing the normalized transmittance of the display device 1 in the second state for each of the E mode only, the O mode only, and a combination of the E mode and the O mode. "E mode" shows only the E mode, that is, the dimming unit 10 has only an E mode liquid crystal panel. "O mode" shows only the O mode, that is, the dimming unit 10 has only an O mode liquid crystal panel. "E+O mode" shows a combination of the E mode and the O mode, that is, the dimming unit 10 has both the E mode and the O mode liquid crystal panels as in the embodiment.

[0066] Normalized transmittance is a value that represents the brightness of the image DSP that can be seen by the user, with the brightness of the image at the viewing angle at which the brightest image can be seen when the display device 1 is operating being taken as 1.0, and the state in which there is no light from the light source 60 (when the display device 1 is not operating) being taken as 0.0, and takes a value within the range of 0.0 to 1.0.

[0067] In FIG. 11 and FIG. 15 and FIG. 17 described later, normalized transmittances from 0.00 to 1.00 are shown at equal intervals along the vertical axis. In FIG. 12 and FIG. 16 and FIG. 18 described later, the top end of the vertical axis is 1.0, and the value of the normalized transmittance is reduced to 1 / 10 for each scale mark downward. FIG. 11 and FIG. 12 only differ in the way of expressing the vertical axis, and the relationship between the viewing angle and the normalized transmittance is the same. In FIG. 11 and FIG. 12 and FIG. 15 to FIG. 18 described later, the horizontal axis direction is shown with the line of sight of the display device 1 viewed from the front as the reference (viewing angle of 0°), and the line of sight from an angle tilted to one side of the first direction X as a viewing angle with a plus (+) value, and the line of sight from an angle tilted to the other side of the first direction X as a viewing angle with a minus (-) value.

[0068] If the light control unit 10 were configured to have only an E-mode liquid crystal panel, the normalized transmittance would be extremely close to 0 at a viewing angle of -30°, while the normalized transmittance would be 0.1 or more at viewing angles on the plus (+) side of -20° and on the minus (-) side of -40°. Thus, with only the E mode, even a slight deviation from the viewing angle of -30° may leave the possibility of the image DSP being unintentionally visible even with squinting eyes.

[0069] On the other hand, when the light control unit 10 has only an O-mode liquid crystal panel, the normalized transmittance is generally 0.1 or more up to about -25° even from the other side of the first direction X. In this way, with only the O-mode, there is a possibility that the suppression of visibility from the other side of the first direction X may be insufficient.

[0070] In contrast, when the light control unit 10 has both E-mode and O-mode liquid crystal panels as in the embodiment, the normalized transmittance falls significantly below 0.1 when the viewing angle is more negative than -20°. Moreover, as in the case of only E-mode, the normalized transmittance does not become 0.1 or more even when the viewing angle is more negative (-) than -40°. Thus, according to the embodiment, since the light control unit 10 has both E-mode and O-mode liquid crystal panels, it is possible to more reliably suppress the visibility of the image DSP from the other side in the first direction X with respect to the display device 1 in the second state.

[0071] In the display device 1, the specific configuration of the display panel 30 that can be combined with the light control unit 10 of the embodiment is not limited to the above-mentioned IPS type liquid crystal panel. The display panel 30 may be of another type as long as it is a so-called transmissive liquid crystal panel having a plurality of pixels that can individually control the degree of light transmission in response to input of image data from the outside. The following describes the configuration of pixels provided in the IPS type liquid crystal panel that can be used as the display panel 30 of the embodiment with reference to FIG. 13.

[0072] Fig. 13 is a plan view showing an example of a pixel layout in the display panel 30. Fig. 13 shows overlapping between the pixel electrodes PE1, PE2 and the common electrode CE when viewed from the fifth polarizing layer 42 side. The pixel electrode P described with reference to Fig. 2 is the pixel electrode PE1 or the pixel electrode PE2 in Fig. 13. The pixel substrate 31 includes a plurality of scanning lines G and a plurality of signal lines S. The plurality of scanning lines G each extend along the first direction X and are arranged at intervals in the second direction Y. The plurality of signal lines S each extend roughly along the second direction Y and are arranged at intervals in the first direction X.

[0073] The pixel electrodes PE1 are aligned along the first direction X. The pixel electrode PE1 has a charging electrode Pa1 overlapping the common electrode CE. The charging electrode Pa1 extends along a direction D1 different from the first direction X and the second direction Y. The pixel electrodes PE2 are aligned along the first direction X. The pixel electrode PE2 has a charging electrode Pa2 overlapping the common electrode CE. The charging electrode Pa2 extends along a direction D2 different from the direction D1. The number of charging electrodes Pa1 and Pa2 may be one or three or more.

[0074] The display device 1 according to the embodiment has been described above with reference to Fig. 1 to Fig. 13. Below, modifications of the embodiment will be described with reference to Fig. 13 to Fig. 20.

[0075] (Variation 1) In the embodiment, the rubbing directions of one of the two alignment films (alignment film 23a and alignment film 24a) facing each other with the liquid crystal LM sandwiched therebetween in the liquid crystal panel 20 are different by 90°. That is, in the embodiment, the twist angle of the liquid crystal panel 20 is 90°, but the twist angle of the liquid crystal panel 20 is not limited to this. For example, the twist angle of the liquid crystal panel 20 may be less than 90°. Furthermore, the twist angle of the liquid crystal panel 20 (for example, the second liquid crystal panel 20B) provided as a liquid crystal panel in an O mode may be smaller than the twist angle of the liquid crystal panel 20 (for example, the first liquid crystal panel 20A) provided as a liquid crystal panel in an E mode. Hereinafter, the relationship between the twist angle and the optical characteristics of the liquid crystal panel 20 will be described with reference to FIG. 14 to FIG. 18.

[0076] Fig. 14 is a graph showing the relationship between the polar angle and the light transmittance when liquid crystal panel 20 provided as an E-mode liquid crystal panel is in operation (ON) for each of the cases where the twist angle is 90° (twist 90°) and where the twist angle is 80° (twist 80°). Figs. 15 and 16 are graphs showing the normalized transmittance on one side and the other side in the first direction X when liquid crystal panel 20 provided as an E-mode liquid crystal panel is in operation (ON) for each of the cases where the twist angle is 90° (twist 90°) and where the twist angle is 80° (twist 80°).

[0077] As shown in Fig. 14, in the case of E mode, when the twist angle is 90°, within the range of the polar angle from 0° to 25° or more and less than 30°, the degree of decrease in transmittance as the polar angle increases is steeper than when the twist angle is 80°. Therefore, as shown in Fig. 15 and Fig. 16, for a liquid crystal panel 20 provided as an E mode liquid crystal panel, within the polar angle range from 0° to 25° or more and less than 30°, that is, within the viewing angle range on the positive (+) side of a viewing angle of -30°, a twist angle closer to 90° tends to be preferable compared to a configuration with a twist angle of 80° in that the normalized transmittance decreases more favorably as the viewing angle approaches the other side of the first direction X.

[0078] On the other hand, in the case of liquid crystal panel 20 provided as an E-mode liquid crystal panel, when the twist angle is 90°, the transmittance becomes higher when the polar angle exceeds 30° compared to when the twist angle is 80°. For this reason, in the viewing angle range on the negative (-) side of -30° or less, it is desirable to lower the normalized transmittance by other means.

[0079] 17 and 18 are graphs showing normalized transmittances on one side and the other side in the first direction X when the liquid crystal panel 20 provided as an O-mode liquid crystal panel is in operation (ON) for a twist angle of 90° (twist 90°) and a twist angle of 80° (twist 80°). As shown in Figs. 17 and 18, in the case of O-mode, when the twist angle is 80°, the transmittance is almost equal to or lower than that when the twist angle is 90° within the range of polar angles from 0° to about 35°. Furthermore, in the case of O-mode, when the polar angle is 40° or more, the transmittance is significantly lower at a twist angle of 80° than that at a twist angle of 90°, and a nearly stable transmittance is obtained. Therefore, for liquid crystal panel 20 provided as an O-mode liquid crystal panel, a twist angle of 80° can ensure a sufficiently low normalized transmittance in the viewing angle range on the positive (-) side, based on a viewing angle of -40°, and tends to provide an even lower normalized transmittance in the viewing angle range on the negative (-) side.

[0080] Based on the respective tendencies of the E mode and the O mode described with reference to FIG. 14 to FIG. 18, in the first modification, as described above, the twist angles of the first liquid crystal panel 20A and the second liquid crystal panel 20B of the light control unit 10 are set so that the twist angle of the liquid crystal panel 20 (for example, the second liquid crystal panel 20B) provided as the O mode liquid crystal panel is smaller than the twist angle of the liquid crystal panel 20 (for example, the first liquid crystal panel 20A) provided as the E mode liquid crystal panel. As a specific example of the twist angle in the first modification, the twist angle of the first liquid crystal panel 20A is set to 90° or an angle closer to 90° even if it is less than 90°. In addition, in this specific example, the twist angle of the second liquid crystal panel 20B is set to 80°. This makes it possible to more reliably obtain both the steeper light-shielding cutoff characteristic on the other side of the first direction X by the E mode and the wider light-shielding viewing angle range by the O mode.

[0081] In addition, since the twist angle in the first modification is different from that in the embodiment, the transmission axis directions V05 and V07 (see FIG. 3) are also set to angles corresponding to the twist angle in the first modification. In addition, by making the slow axis direction V08 of the phase difference generation layer 52 larger (for example, about −27.5° to −28°), even if the specific example of the twist angle in the first modification is adopted, the light can be transmitted through the transmission path LV as in the embodiment. Of course, the light can be transmitted through the transmission path LV by making the polarization-related characteristics other than the slow axis direction V08 correspond to the first modification, such as by adjusting the transmission axis direction V09 and the transmission axis direction V11.

[0082] (Variation 2) 19 is a schematic diagram showing a main configuration example of a display device 1A according to Modification 2. The display device 1A is similar to the embodiment except that the retardation generating layer 51 is omitted from the configuration of the display device 1 according to the embodiment (see FIG. 1) and the matters related to the polarization angle of the polarized light generating layer 53, which will be noted below.

[0083] In the embodiment, the phase difference generating layer 51 is provided, but by changing the polarization angle of the polarization generating layer 53, which is set to transmit the light emitted from the other surface of the light source 60 as 0° polarized light in the embodiment, the phase difference generating layer 51 can be omitted as shown in Fig. 19. The polarization angle of the polarization generating layer 53 in the second modification will be described below with reference to Fig. 20.

[0084] 20 is a schematic diagram showing polarization axis directions V21, V22, which are examples of polarization angles of the polarized light generating layer 53 that can be adopted in the second modification, and angle ranges R21, R22 in which the polarization angles can be set. For example, assume that there is a configuration that reflects light LS3 from the display device 1 to generate light LS4, as in the reflector 102 shown in FIG. 8. In this case, when the light LS4 reaches the user U2, it may unintentionally establish a state in which the image DSP output by the display device 1 in the second state is also visible from the user U2. In this case, for example, when FIG. 8 is an example of the inside of a four-wheeled vehicle, the side window on the passenger side may function as the reflector 102, and this may be established.

[0085] Therefore, in the second modification, the polarization angle of the polarization generating layer 53 is determined so as to make it more difficult to generate the light LS3. Specifically, when making it more difficult to generate the light LS3 in the relationship between the display device 1 and the user U2 shown in FIG. 8, the polarization angle is determined along the XY plane and in a direction intersecting the first direction X and the second direction Y, as in the polarization axis direction V22 of FIG. 20. More specifically, in this case, the polarization generating layer 53 of the second modification is determined so as to polarize the light emitted from the other surface of the light source 60 at +135° and transmit it. In this case, the light transmission path LV is not established from the slow axis direction V02 to the transmission axis direction V11 in the embodiment described with reference to FIG. 3, but the light transmission path LV is established even in this case by reversing the relationship between one side of the first direction X and the other side of the first direction X in the description of the polarization described with reference to FIG. 3. Due to such a polarization axis direction V22, the light emitted from the light source 60 and transmitted through the polarized light generating layer 53 shows an elliptical light spread as shown in the light region L22. The relationship between the major axis of the ellipse shown in FIG. 20 as the light region L22, the minor axis of the ellipse, and the polarization axis direction V22 is such that the acute angle between the major axis and the polarization axis direction V22 is smaller than the acute angle between the minor axis and the polarization axis direction V22. Such an elliptical spread of light suppresses the generation of the light LS3 traveling from the display device 1 toward the reflector 102 in FIG. 8.

[0086] In addition, when the user U2 shown in FIG. 8 is a driver of a four-wheeled vehicle, for example, the steering wheel of the four-wheeled vehicle is located at or near the position of the configuration 101 facing the user U2 in the third direction Z. That is, if FIG. 8 is an example of the inside of a four-wheeled vehicle, the example is an example of a left-hand steering wheel. In the case of a right-hand steering wheel, the positional relationship between the display device 1 and the configuration 101 is reversed. That is, in this case, the user U2 is in a state of looking at the display device 1 from the front, and the user U1 is in a state of looking at the configuration 101 obliquely from one side of the first direction X. In this case, for example, by rotating the retardation generating layer 51, the light control unit 10, and the retardation generating layer 52 of the configuration of the display device 1 by 180° with the third direction Z as the rotation axis relative to the other configurations, the relationship between one side of the first direction X and the other side of the first direction X in the description with reference to FIG. 7 can be reversed, so that the relationship between the front view and the oblique view shown in FIG. 9 can be similarly realized. That is, the display device 1 can appropriately set the orientation relationship of "the relationship between one side of the first direction X and the other side of the first direction X" in the description with reference to Fig. 7 depending on the physical orientation of the liquid crystal panel 20. Also, in the case of a right-hand drive vehicle, the above-mentioned "state in which the image DSP output by the display device 1 in the second state is also visible from the user U2" may be unintentionally established by the reflector 103 on the user U2 side instead of the reflector 102 on the user U1 side in the case of a left-hand drive vehicle.

[0087] In the case of a right-hand drive vehicle, the polarization generating layer 53 of the second modified example has a polarization axis direction V21 determined so that the light emitted from the other surface of the light source 60 is polarized at +45° and transmitted. In this case, the light transmission path LV is established by a configuration in which the phase difference generating layer 51 is removed from the embodiment described with reference to FIG. 3. Due to such a polarization axis direction V21, the light emitted from the light source 60 and transmitted through the polarization generating layer 53 shows an elliptical light spread different from the light region L22, as in the light region L21. The relationship between the major axis of the ellipse shown in FIG. 20 as the light region L21, the minor axis of the ellipse, and the polarization axis direction V21 is such that the acute angle between the major axis and the polarization axis direction V21 is smaller than the acute angle between the minor axis and the polarization axis direction V21.

[0088] The polarization axis of the polarized light generating layer 53 in the second modification is not limited to the polarization axis directions V21 and V22. For example, in the case of a right-hand drive vehicle, the polarization axis may be set within an angle range R21 of -15° to +105°. In addition, in the case of a left-hand drive vehicle, the polarization axis may be set within an angle range R22 of +75° to +195°. However, even within the angle ranges R21 and R22, it is preferable that the polarization axis is not aligned with the arrangement direction of the user U1 and the user U2, that is, the direction corresponding to the first direction X (0°, 180°). Note that a configuration combining both the first modification and the second modification can also be realized.

[0089] As described above, the display device (display device 1) includes a display panel (display panel 30) having a display area for outputting an image, a light source (light source 60) for irradiating light from one side of the display panel, and a dimming unit (dimming unit 10) disposed between the display panel and the light source so as to be capable of changing the degree of light transmission between the display panel and the light source. The dimming unit includes a first polarizing layer (first polarizing layer 11), a first liquid crystal panel (first liquid crystal panel 20A), a second polarizing layer (second polarizing layer 12), a second liquid crystal panel (second liquid crystal panel 20B), and a third polarizing layer (third polarizing layer 13) that are overlapped from the light source side toward the display panel side, and one of the first liquid crystal panel and the second liquid crystal panel (for example, the first liquid crystal panel 20A) is provided as an E-mode liquid crystal panel, and the other of the first liquid crystal panel and the second liquid crystal panel (for example, the second liquid crystal panel 20B) is provided as an O-mode liquid crystal panel.

[0090] This makes it possible to realize an image display output that utilizes both the advantages of the E-mode liquid crystal panel and the O-mode liquid crystal panel. The advantage of the E-mode liquid crystal panel is a steep reduction in light transmittance with respect to the ray of light at a specific angle (for example, near a viewing angle of -30°). The advantage of the O-mode liquid crystal panel is a stable reduction in light transmittance in a wider range (for example, on the negative (-) side of a viewing angle of -30°). In addition, both the E-mode and the O-mode can transmit light that allows an image to be sufficiently viewed, except for a viewing angle range where the light transmittance is particularly reduced. In this way, according to the embodiment, a viewing angle range where an image is viewable and a viewing angle range where an image is not viewable can be simultaneously established, while a viewing angle range where an image is not viewable can be more reliably secured.

[0091] In addition, the first rubbing direction of one of the two alignment films (alignment films 23a, 24a) arranged on the light source (light source 60) side and the second rubbing direction of the other of the two alignment films (alignment film 24a) arranged on the display panel side are common to the first liquid crystal panel (first liquid crystal panel 20A) and the second liquid crystal panel (second liquid crystal panel 20B), so that two identical liquid crystal panels (liquid crystal panel 20) can be prepared, one of which is an E-mode liquid crystal panel and the other is an O-mode liquid crystal panel. Therefore, there is no need to manufacture the E-mode liquid crystal panel and the O-mode liquid crystal panel separately, and the display device of the embodiment can be provided as a display device with higher mass productivity and lower cost.

[0092] In addition, because the twist angle of the liquid crystal in an O-mode liquid crystal panel is smaller than that in an E-mode liquid crystal panel, the advantages of both the E-mode liquid crystal panel and the O-mode liquid crystal panel described above can be utilized to an even greater extent.

[0093] Furthermore, since the twist angle of the liquid crystal in the first liquid crystal panel (first liquid crystal panel 20A) and the second liquid crystal panel (second liquid crystal panel 20B) is less than 90°, it is possible to enhance and utilize both the advantages of the E-mode liquid crystal panel and the O-mode liquid crystal panel described above.

[0094] Furthermore, the display device (display device 1) is provided with a polarization generating layer (polarization generating layer 53) that is provided between the light source (light source 60) and the dimming unit (dimming unit 10) and polarizes the light emitted from the light source in a specific direction, and the specific direction is a direction (e.g., polarization axis direction V21 or polarization axis direction V22) that intersects all four sides of the rectangular display area (display area AA), making it easier to prevent unintended viewing of an image due to a reflector (e.g., reflector 102) that is in the opposite position as seen by the user who wishes to prevent the image from being viewed through a squinted line.

[0095] Furthermore, when the first liquid crystal panel (first liquid crystal panel 20A) and the second liquid crystal panel (second liquid crystal panel 20B) are in operation, the light control unit (display panel 30) differentiates the degree of light transmission inclined to one side in the longitudinal direction of the rectangular display panel (one side in the first direction X) from the degree of light transmission inclined to the other side in the longitudinal direction (the other side in the first direction X) based on the opposing direction (third direction Z) between the display panel (display panel 30) and the light source (light source 60). This makes it possible to simultaneously establish a viewing angle range in which an image is visible and a viewing angle range in which an image is not visible.

[0096] The positional relationship between the E-mode liquid crystal panel and the O-mode liquid crystal panel between the display panel (display panel 30) and the light source (light source 60) may be reversed from that in the embodiment. In that case, the relationship between the transmission axis direction and the absorption axis direction of each of the first polarizing layer 11, the second polarizing layer 12, and the third polarizing layer 13 may be reversed. Also, the slow axis directions V02 and V08 of the retardation generating layers 51 and 52 may be changed so as to be linearly symmetrical with respect to the second direction Y.

[0097] Furthermore, other advantageous effects brought about by the aspects described in this embodiment that are obvious from the description in this specification or that can be appropriately thought of by a person skilled in the art are naturally understood to be brought about by the present disclosure. [Explanation of symbols]

[0098] 1 Display device 10. Dimming section 11 First polarizing layer 12 Second polarizing layer 13 Third polarizing layer 20 Liquid crystal panel 20A 1st LCD panel 20B Second LCD panel 23a, 24a Alignment film 30 Display Panel 53 Polarization generation layer 60 light source

Claims

1. a display panel having a display area for outputting an image; a light source that irradiates light from one side of the display panel; a light control unit that is interposed between the display panel and the light source and is capable of changing a degree of light transmission between the display panel and the light source, The light control unit includes: a first polarizing layer, a first liquid crystal panel, a second polarizing layer, a second liquid crystal panel, and a third polarizing layer are overlapped in this order from the light source side to the display panel side; one of the first liquid crystal panel and the second liquid crystal panel is provided as an E-mode liquid crystal panel, and the other of the first liquid crystal panel and the second liquid crystal panel is provided as an O-mode liquid crystal panel; Display device.

2. a first rubbing direction by one of two alignment films disposed on the light source side of the two alignment films facing each other with a liquid crystal therebetween, and a second rubbing direction by the other of the two alignment films disposed on the display panel side of the two alignment films, the first liquid crystal panel and the second liquid crystal panel being common to each other; The display device according to claim 1 .

3. The O-mode liquid crystal panel has a smaller twist angle of liquid crystal than the E-mode liquid crystal panel. The display device according to claim 1 .

4. The first liquid crystal panel and the second liquid crystal panel have a twist angle of the liquid crystal less than 90°. The display device according to claim 3 .

5. a polarization generating layer provided between the light source and the dimming unit to polarize the light emitted from the light source in a specific direction; The specific direction is a direction that intersects with all four sides of the rectangular display area. The display device according to claim 1 .

6. the light control unit, when the first liquid crystal panel and the second liquid crystal panel are in operation, differentiates a degree of light transmission inclined to one side in a longitudinal direction of the rectangular display panel from a degree of light transmission inclined to the other side in the longitudinal direction, based on a facing direction of the display panel and the light source. The display device according to claim 1 .

Images