Display device

Abstract

The invention provides a display device capable of detecting the operation state of a liquid crystal panel. A display device (1) is provided with: a display panel (30) having a display region (AA) for outputting an image; a light source (60) that irradiates light toward one surface side of the display panel (30); a liquid crystal panel (20) that is interposed between the display panel (30) and the light source (60) and that is provided so as to be capable of changing the degree of light transmission between the display panel (30) and the light source (60); and a control unit that controls the potential difference between two electrodes (FE1, FE2) facing each other with the liquid crystal interposed therebetween in the liquid crystal panel (20), and the operating liquid crystal panel (20) differs the degree of transmission of light inclined to one side of the first direction (X) with respect to the third direction (Z) from the degree of transmission of light inclined to the other side. The potential difference corresponds to the inclination angle at which the degree of light transmission is lower when the liquid crystal panel (20) is operated.

Description

Technical Field

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

[0002] In a display device, there is a need to limit 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 vehicle, it is sought to achieve a viewing angle range in which an image can be viewed from the passenger seat side and the image cannot be viewed from the driver's seat side as long as the vehicle is driving. In order to achieve such a viewing angle range, a technology has been proposed in which a dimming liquid crystal panel is superimposed on a panel for image display (for example, Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-195388 Summary of the invention

[0006] In a display device that can limit the angular range of a visual image, there is a demand for being able to set the angular range of the visual image more flexibly. For example, a display device can be mounted on a four-wheeled vehicle of various models. In four-wheeled vehicles of different models, the positional relationship between the driver's seat and the display device may be different. A display device is required that can independently limit the angular range of the visual image corresponding to the positional relationship between the driver's seat and the display device of each of such four-wheeled vehicles of various models. In addition, not limited to four-wheeled vehicles, it is desired to be able to more flexibly determine the angular range of the visual image in all environments where the display device may be set. In previous display devices, it was difficult to meet such a requirement.

[0007] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide a display device capable of more flexibly setting a viewing angle range in which an image can be viewed.

[0008] A display device in one embodiment of the present invention comprises: a display panel having a display area for outputting an image; a light source that irradiates light toward one side of the display panel; a liquid crystal panel that is interposed between the display panel and the light source and is configured to be able to change the degree of light transmittance between the display panel and the light source; and a control unit that controls the potential difference between two electrodes that are opposite to each other across the liquid crystal in the liquid crystal panel, wherein when the liquid crystal panel is in operation, the degree of light transmittance inclined toward one side of the length direction of the rectangular display panel is different from the degree of light transmittance inclined toward the other side of the length direction, based on the relative direction of the display panel and the light source, and the potential difference corresponds to an angle of inclination at which the degree of light transmittance is lower when the liquid crystal panel is in operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram showing a main configuration example of a display device according to an embodiment.

[0010] Figure 2 It is a schematic cross-sectional view of each structure included in the display device.

[0011] Figure 3 This is a diagram showing changes in the polarization direction of light generated by a light source until the light is emitted to the other surface side of the display device.

[0012] Figure 4 The diagram shows the relationship between the rubbing directions R06a and R06b of the alignment films included in the second liquid crystal panel and the transmission axis directions of the second and third polarizing layers that are disposed opposite to each other in the third direction with the second liquid crystal panel interposed therebetween.

[0013] Figure 5 This is a diagram showing the alignment of liquid crystal molecules when the liquid crystal panel is not in operation (OFF).

[0014] Figure 6 This is a diagram showing the alignment of liquid crystal molecules when the liquid crystal panel is in operation (ON).

[0015] Figure 7 This is a diagram showing an example of the viewing angle characteristics of a display device that occurs according to the degree of light transmission when the liquid crystal panel is operating (ON).

[0016] Figure 8 This is a schematic diagram showing an example of the relationship between a display device, a user who can view images regardless of the operation / non-operation (ON / OFF) of the liquid crystal panel, and a user who cannot view images when the liquid crystal panel is in operation (ON).

[0017] Fig. 9 This is a schematic diagram showing the difference between images viewed by a user who views the display device from the front and by a user who views the display device from an angle.

[0018] Fig.10 The graphs show the relationship between the polar angle and the light transmittance when the liquid crystal panel is in operation (ON) for the E mode and the O mode, respectively.

[0019] Fig.11 This is a graph showing the normalized transmittance in the display device in the second state in each of the E mode only, the O mode only, and the combination of the E mode and the O mode.

[0020] Fig.12 This is a graph showing the normalized transmittance in the display device in the second state in each of the E mode only, the O mode only, and the combination of the E mode and the O mode.

[0021] Fig.13 It is a plan view showing an example of a pixel layout in a display panel.

[0022] Fig.14 This is a diagram showing an example of the relationship between three viewing angles on the negative (-) side and the level of the normalized transmittance.

[0023] Fig.15 This is a diagram showing an example of the relationship between three viewing angles on the negative (-) side and control of the normalized transmittance by controlling the voltage applied to the liquid crystal.

[0024] Fig.16 A graph showing an example of each normalized transmittance when the voltage applied to the liquid crystal is any one of 2 [V] to 2.7 [V] (every 0.1 V).

[0025] Fig.17 This is a graph showing an example of the relationship between the voltage applied to liquid crystal and the cut angle.

[0026] Fig.18 This is a schematic diagram showing an example of the positional angle relationship between the display device and a seat where a user who is expected to view an image on the display device at an angle is seated.

[0027] Fig.19 This is a schematic diagram showing an example of a configuration in which a camera is used to determine the positional angle relationship between a user and a display device.

[0028] Description of Reference Numerals

[0029] 1: Display device

[0030] 10: Dimming unit

[0031] 20: LCD panel

[0032] 20A: 1st LCD panel

[0033] 20B: Second LCD panel

[0034] 23a, 24a: Oriented film

[0035] 30: Display Panel

[0036] 60: Light Source

[0037] 70: Control Department

[0038] Ca1, Ca2: Camera

[0039] FE1, FE2: Electrodes DETAILED DESCRIPTION

[0040] Hereinafter, various embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the disclosed content is only an example, and solutions that are more easily conceived by those skilled in the art for appropriate changes that retain the spirit of the invention are of course included in the scope of the present disclosure. In addition, in order to make the description clearer, the drawings show schematically the width, thickness, shape, etc. of each part compared to the actual form, but this is only an example and does not limit the interpretation of the present disclosure. In addition, in this specification and each of the drawings, the same elements as those described in the drawings that have already appeared are sometimes marked with the same figure numbers and detailed descriptions are omitted.

[0041] Figure 1 1 is a schematic diagram showing a main structural example of a display device 1 according to an embodiment. The display device 1 includes a dimming unit 10, a display panel 30, a light source 60, a phase difference generating layer 51, and a phase difference generating layer 52. The direction in which the dimming unit 10, the display panel 30, the light source 60, the phase difference generating layer 51, and the phase difference generating layer 52 overlap is set as a third direction Z. In addition, one of the two directions orthogonal to the third direction Z is set as a first direction X, and the other direction is set as a second direction Y. The first direction X is orthogonal to the second direction Y. The display device 1 overlaps the light source 60, the phase difference generating layer 51, the dimming unit 10, the phase difference generating layer 52, and the display panel 30 in this order from one side to the other side of the third direction Z.

[0042] Figure 2 1 is a schematic cross-sectional view of each structure of the display device 1. Figure 2 In the embodiment, there is a gap between the light source 60, the phase difference generating layer 51, the dimming unit 10, the phase difference generating layer 52, and the display panel 30. The gap is provided for the purpose of making the drawing easier to understand, and is not required in the actual display device 1 (see Figure 1 ).

[0043] The dimming unit 10 is constructed such that the first polarizing layer 11, the first liquid crystal panel 20A, the second polarizing layer 12, the second liquid crystal panel 20B, and the third polarizing layer 13 are overlapped from one side of the third direction Z to the other side. The first polarizing layer 11, the second polarizing layer 12, and the third polarizing layer 13, as well as the fourth polarizing layer 41 and the fifth polarizing layer 42 described later, are optical components arranged in a manner to transmit polarized light in a specific direction to the maximum extent. The specific direction is recorded as the transmission axis direction. The transmission axis direction is along the polarizer. That is, the transmission axis direction is orthogonal to the third direction Z. In addition, the direction orthogonal to the transmission axis direction and the third direction Z is recorded as the absorption axis direction. The absorption axis direction is the polarization direction in which light is most difficult to transmit in the polarizer.

[0044] 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 structure as devices except that they are installed at different positions. Hereinafter, when the liquid crystal panel 20 is recorded, it includes the first liquid crystal panel 20A and the second liquid crystal panel 20B. That is, 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) liquid crystal panel.

[0045] The liquid crystal panel 20 is a structure in which a first substrate 21 is provided on one side and a second substrate 22 is provided on the other side via a liquid crystal LM. The first substrate 21 and the second substrate 22 are translucent substrates. The translucent substrate is, for example, a glass substrate, but is not limited thereto, and may also be a substrate based on other translucent materials. Hereinafter, when it is recorded as one side, it refers to the surface on one side in the third direction Z in the plate-like structure. In addition, when it is recorded as the other side, it refers to the surface on the other side in the third direction Z in the plate-like structure.

[0046] An electrode FE2 is formed on the other surface of the first substrate 21. An electrode FE1 is formed on one surface of the second substrate 22. The electrode FE2 and the electrode FE1 are electrodes provided to cover the display area AA. The other surface of the electrode FE2 and the other surface of the first substrate 21 in the range where the electrode FE2 is not formed are covered by the insulating layer 23. One surface of the electrode FE1 and one surface of the second substrate 22 in the range where the electrode FE1 is not formed are covered by the insulating layer 24. The display area AA will be described later.

[0047] At least one of the electrode FE2 and the electrode FE1 is provided so that the potential can be changed according to the ON / OFF operation of the liquid crystal panel 20. That is, the voltage generated between the electrode FE2 and the electrode FE1 is different when the liquid crystal panel 20 is in operation (ON) and when it is not in operation (OFF).

[0048] Liquid crystal LM is sandwiched between the insulating layer 23 and the insulating layer 24, at least in the display area AA. In addition, outside the display area AA, a sealant 25 is sandwiched between the insulating layer 23 and the insulating layer 24. Although not shown in the figure, the sealant 25 is a frame-shaped member that surrounds the liquid crystal LM when viewed from the front on a plane (XY plane) that is orthogonal to the third direction Z. The liquid crystal LM is surrounded by the sealant 25 between the insulating layer 23 and the insulating layer 24, thereby being sealed in the liquid crystal panel 20.

[0049] In addition, an orientation film 23a is provided on the other surface of the insulating layer 23 in a range covering at least the display area AA. An orientation film 24a is provided on one surface of the insulating layer 24 in a range covering at least the display area AA. The orientation films 23a and 24a orient the liquid crystal molecules contained in the liquid crystal LM in a specific direction. If the potential difference between the electrode FE2 and the electrode FE1 changes, the orientation of the liquid crystal molecules changes.

[0050] 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, which is provided so as to be able to individually control the degree of light transmission at the positions of the plurality of pixels in response to input of image data from the outside.

[0051] Figure 2 The display panel 30 is a so-called IPS (In Plane Switching) liquid crystal panel. The display panel 30 is provided with a pixel substrate 31 on one side of the third direction Z and a counter substrate 32 on the other side via the liquid crystal LQ. In addition, a fourth polarizing layer 41 is provided on one side of the pixel substrate 31. A fifth polarizing layer 42 is provided on the other side of the counter substrate 32. Hereinafter, when described as a panel portion DP, it refers to the portion of the structure of the display panel 30 other than the fourth polarizing layer 41 and the fifth polarizing layer 42.

[0052] On the other side of the pixel substrate 31, a common electrode CE, an insulating layer 33, a pixel electrode P, an insulating layer 34, etc. are stacked from one side to the other side in the third direction Z. A color filter 35, etc. are stacked on one side of the counter substrate 32. In addition, outside the display area AA, a seal 36 is sandwiched 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 surrounded by the seal 36 between the insulating layer 34 and the color filter 35, and is thus sealed in the display panel 30.

[0053] The display area AA is an area in which a plurality of pixel electrodes P are arranged in the display panel 30. The plurality of pixel electrodes P are arranged two-dimensionally along the X-Y plane in the display area AA. The display panel 30 is a so-called active matrix display panel that is configured in such a way that an arbitrary image can be displayed and output by individually controlling the degree of light transmission in each pixel electrode P. More specifically, in the display panel 30 of the embodiment, a potential serving as a reference is provided to the common electrode CE. In addition, by providing a separate potential (pixel signal) to the plurality of pixel electrodes P, 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 for displaying and outputting an image.

[0054] The phase difference generating layers 51 and 52 are optical components that change the phase of light entering from one side in the third direction Z and pass the light to the other side in the third direction Z. The phase difference generating layers 51 and 52 of the embodiment are so-called half-wave plates.

[0055] The light source 60 emits light toward the other side where the polarization generation layer 53 is provided. The polarization generation layer 53 is an optical component that makes the light emitted from the other side of the light source 60 polarized at a specific angle. The polarization generation layer 53 is, for example, DBEF (Dual Brightness Enhancement Film), but is not limited thereto, as long as it is a structure that can make the light emitted from the other side of the light source 60 polarized at a specific angle. The light generated by the light source 60 is emitted to the other side of the display device 1 via the polarization generation layer 53, the dimming unit 10, the fourth polarization layer 41, the display panel 30, and the fifth polarization layer 42.

[0056] Next, refer to Figure 3 A description will be given of a change in the polarization direction of light generated by the light source 60 until the light is emitted to the other surface of the display device 1 .

[0057] Figure 3 1 is a diagram showing the change in polarization direction of light generated by the light source 60 until it is emitted to the other side of the display device 1. In the following description, polarized light along the first direction X is assumed to be polarized light of 0°. Figure 3 In the description of the polarization angle, the angle of polarization light is represented by a minor angle less than 180°, based on the polarization light of 0°. Figure 3 In the description of , a change in the polarization direction of light that rotates counterclockwise by r° along the X-Y plane is described as a “change of +r°”, and a change that rotates in the opposite direction (clockwise) by r° is described as a “change of −r°”. r is a real number greater than 0.

[0058] In the embodiment, the polarization generating layer 53 determines the polarization axis direction V01 so that the light emitted from the other side of the light source 60 is transmitted as 0° polarized light. Therefore, the polarized light that passes through the polarization generating layer 53 and enters the phase difference generating layer 51 is 0° polarized light.

[0059] The phase difference generating layer 51 is a 1 / 2 wavelength plate as described above. The phase difference generating layer 51 of the embodiment causes a change in the counterclockwise (+) direction. In addition, the phase difference generating layer 51 determines the slow axis direction V02 in such a way that it becomes +22.5° relative to the polarized light (0°) transmitted from the polarization generating layer 53. Thus, by transmitting through the phase difference generating layer 51, the polarized light undergoes a change of +45°. Therefore, the polarized light transmitted through the phase difference generating layer 51 and incident on the first polarization layer 11 is 45° polarized light. Figure 3 , an angle V02b of polarized light incident on the phase difference generating layer 51 and an angle V02a of polarized light after passing through the phase difference generating layer 51 are shown.

[0060] The first polarizing layer 11 determines the transmission axis direction V03 so as to transmit 45° polarized light to the maximum extent. Therefore, the light transmitted through the phase difference generating layer 51 can be transmitted through the first polarizing layer 11. In addition, the polarized light transmitted through the first polarizing layer 11 and incident on the first liquid crystal panel 20A is 45° polarized light.

[0061] The liquid crystal panel 20 is set in a manner to provide a +90° change to the polarized light transmitted from one side to the other side in the third direction Z. That is, the polarized light undergoes a +90° change by being transmitted from the first liquid crystal panel 20A. Therefore, the polarized light transmitted from the first liquid crystal panel 20A and incident on the second polarizing layer 12 is 135° polarized light. Figure 3 , an angle V04b of polarized light incident on the first liquid crystal panel 20A and an angle V04a of polarized light after passing through the first liquid crystal panel 20A are shown.

[0062] The second polarizing layer 12 determines the transmission axis direction V05 so as to transmit polarized light of 135° to the maximum extent. Therefore, the light transmitted through the first liquid crystal panel 20A can be transmitted through the second polarizing layer 12. In addition, the polarized light transmitted through the second polarizing layer 12 and incident on the second liquid crystal panel 20B is polarized light of 135°.

[0063] The polarized light changes by +90° when passing through the second liquid crystal panel 20B. Therefore, the polarized light passing through the second liquid crystal panel 20B and entering the third polarizing layer 13 can be said to be polarized light of 225°, which is the same as polarized light of 45°. Figure 3 , an angle V06b of polarized light incident on the second liquid crystal panel 20B and an angle V06a of polarized light after passing through the second liquid crystal panel 20B are shown.

[0064] The third polarizing layer 13 determines the transmission axis direction V07 so as to transmit 45° polarized light to the maximum extent. Therefore, the light transmitted from the second liquid crystal panel 20B can be transmitted from the third polarizing layer 13. In addition, the polarized light transmitted from the third polarizing layer 13 and incident on the phase difference generating layer 52 is 45° polarized light.

[0065] The phase difference generating layer 52 is a 1 / 2 wavelength plate as described above. The phase difference generating layer 52 of the embodiment causes a change in the clockwise (-) direction. In addition, the phase difference generating layer 52 determines the slow axis direction V08 in such a way that it becomes -22.5° relative to the polarized light (45°) transmitted from the polarization generating layer 53. Thus, by transmitting through the phase difference generating layer 52, the polarized light undergoes a change of -45°. Therefore, the polarized light transmitted from the phase difference generating layer 52 and incident on the fourth polarization layer 41 is polarized light of 0°. Figure 3 , an angle V08b of polarized light incident on the phase difference generating layer 52 and an angle V08a of polarized light after passing through the phase difference generating layer 52 are shown.

[0066] The fourth polarizing layer 41 determines the transmission axis direction V09 so as to transmit 0° polarized light to the maximum extent. Therefore, the light transmitted through the phase difference generating layer 52 can be transmitted through the fourth polarizing layer 41. In addition, the polarized light transmitted through the fourth polarizing layer 41 and incident on the panel portion DP is 0° polarized light.

[0067] The panel portion DP is arranged so as to provide a +90° change to the polarized light transmitted from one side to the other side in the third direction Z. That is, the polarized light undergoes a +90° change by being transmitted through the panel portion DP. Therefore, the polarized light transmitted through the panel portion DP and incident on the fifth polarizing layer 42 is 90° polarized light. Figure 3 , an angle V10b of polarized light incident on the panel portion DP and an angle V10a of polarized light transmitted through the panel portion DP are shown.

[0068] The fifth polarizing layer 42 determines the transmission axis direction V11 so as to transmit 90° polarized light to the maximum extent. Therefore, light transmitted from the panel portion DP can be transmitted from the fifth polarizing layer 42. In this way, a transmission path LV of light from the light source 60 to the other side of the fifth polarizing layer 42 is established.

[0069] Next, refer to Figures 4 to 7 The liquid crystal panel 20 will be described in more detail.

[0070] Figure 4The diagram shows the relationship between the rubbing directions R06a and R06b of the orientation films 23a and 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 opposite to each other in the third direction Z across the second liquid crystal panel 20B. Figure 4 and the following Figure 7 In the description of the first direction X, the side (in Figure 4 The direction of the right side is set as the direction of 0°. In addition, the direction that forms an angle opening in the counterclockwise direction with the 0° direction is set as the direction of the positive (+) angle (°), and the direction that forms an angle opening in the clockwise direction is set as the direction of the negative (-) angle (°).

[0071] The alignment films 23a and 24a respectively orient the liquid crystal molecules in specific directions, and therefore are subjected to rubbing treatment on the contact surface side with the liquid crystal LM. The specific direction determined by the relevant rubbing treatment is the rubbing direction. The rubbing direction R06b of the alignment film 23a is 225° (-135°). The rubbing direction R06a of the alignment film 24a is 315° (-45°).

[0072] In the second liquid crystal panel 20B, the first substrate 21 on which the alignment film 23a is laminated faces the second polarizing layer 12 on one side. Figure 3 and Figure 4 As shown in FIG. 1 , the transmission axis direction V05 of the second polarizing layer 12 is 135°. That is, the rubbing direction R06b of the alignment film 23a is orthogonal to the transmission axis direction V05 of the second polarizing layer 12.

[0073] 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. Figure 3 and Figure 4 As shown in FIG. 1 , the transmission axis direction V07 of the third polarizing layer 13 is 45°. That is, the rubbing direction R06a of the alignment film 24a is orthogonal to the transmission axis direction V07 of the third polarizing layer 13.

[0074] As reference Figure 4 As described above, in the second liquid crystal panel 20B of the embodiment, the rubbing direction of the alignment film stacked on the substrate is orthogonal to the alignment axis of the polarizing layer abutting the substrate. That is, the second liquid crystal panel 20B is a so-called O-mode liquid crystal panel.

[0075] In addition, as described above, the first liquid crystal panel 20A and the second liquid crystal panel 20B have a common structure as liquid crystal panels (liquid crystal panel 20). Therefore, the rubbing direction R06b of the orientation film 23a on one side of the first liquid crystal panel 20A is 225° (-135°) in the same manner as the second liquid crystal panel 20B. Here, the transmission axis direction V03 of the first polarizing layer 11 disposed on one side of the first liquid crystal panel 20A is 45°. In addition, the rubbing direction R06a of the orientation film 24a on the other side of the first liquid crystal panel 20A is 315° (-45°) in the same manner as the second liquid crystal panel 20B. The transmission axis direction V05 of the second polarizing layer 12 disposed on the other side of the first liquid crystal panel 20A is 135°. Thus, in the first liquid crystal panel 20A of the embodiment, the rubbing direction of the orientation film stacked on the substrate is parallel to the orientation axis of the polarizing layer abutting against the substrate. That is, the first liquid crystal panel 20A is set as a so-called E-mode liquid crystal panel.

[0076] More specifically, the liquid crystal molecules contained in the liquid crystal LM can be regarded as having an ellipsoidal shape. Here, the major axis direction of the ellipsoid is ne (n extraordinary ) axis. In addition, the minor axis direction of the ellipsoid perpendicular to the ne axis is set to no(n ordinary ) axis. In the E mode, the rubbing direction of the orientation film 23a is determined in such a way that the transmission axis direction of the polarization layer opposite to the orientation film 23a via the first substrate 21 is the same as the ne axis, and the rubbing direction of the orientation film 24a is determined in such a way that the transmission axis direction of the polarization layer opposite to the orientation film 24a via the second substrate 22 is the same as the ne axis. In the O mode, the rubbing direction of the orientation film 23a is determined in such a way that the transmission axis direction of the polarization layer opposite to the orientation film 23a via the first substrate 21 is the same as the no axis, and the rubbing direction of the orientation film 24a is determined in such a way that the transmission axis direction of the polarization layer opposite to the orientation film 24a via the second substrate 22 is the same as the no axis.

[0077] The rubbing direction does not limit the polarized light to be transmitted. That is, the alignment films 23a and 24a transmit light regardless of the rubbing direction.

[0078] The rubbing direction of the alignment films 23a and 24a affects the alignment of the liquid crystal molecules contained in the liquid crystal LM. Figure 4 and the following Figure 5 and Figure 6In the figure, as a liquid crystal molecule included in the liquid crystal LM, the liquid crystal molecule LM2 is shown. In addition, the liquid crystal molecule located on the side of the orientation film 23a and oriented along the rubbing direction R06b among the liquid crystal molecule LM2 is particularly recorded as the liquid crystal molecule LMB. In addition, the liquid crystal molecule located on the side of the orientation film 24a and oriented along the rubbing direction R06a among the liquid crystal molecule LM2 is particularly recorded as the liquid crystal molecule LMA. In addition, the liquid crystal molecule located approximately in the middle between the liquid crystal molecule LMA and the liquid crystal molecule LMB in the third direction Z among the liquid crystal molecule LM2 is particularly recorded as the liquid crystal molecule LMC.

[0079] like Figure 4 As shown, when observing from the front viewpoint of the X-Y plane, for the liquid crystal molecules LM2, the closer the liquid crystal molecules to the orientation film 23a are, the closer the orientation is to the rubbing direction R06b, and the closer the liquid crystal molecules to the orientation film 24a are, the closer the orientation is to the rubbing direction R06a. By the continuity of the change in the orientation of the plurality of liquid crystal molecules LM2 arranged in the third direction Z, the liquid crystal panel 20 provides a +90° change in polarized light transmitted from one side of the third direction Z to the other side.

[0080] Figure 5 It is a diagram showing the alignment of the liquid crystal molecules LM2 when the liquid crystal panel 20 is not in operation (OFF). Figure 6 2 is a diagram showing the orientation of the liquid crystal molecules LM2 when the liquid crystal panel 20 is in operation (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 in operation (OFF), Figure 5 As shown in FIG. 1 , the long axis direction LX of the liquid crystal molecule LM2 is substantially along the XY plane. On the other hand, when the liquid crystal panel 20 is in operation (ON), the electrodes FE2 and FE1 (see FIG. 1 ) are connected. Figure 2 ), the orientation of the liquid crystal molecules LM2 changes so that the long axis direction LX faces the third direction Z. Therefore, when the liquid crystal panel 20 is in operation (ON), as shown in FIG. Figure 6 As shown, the long axis direction LX of the liquid crystal molecule LM2 intersects the XY plane.

[0081] The liquid crystal panel 20 is referenced Figure 5 When the display device 1 is not in operation (OFF), there is almost no difference in the degree of light transmission between the one side in the first direction X and the other side in the first direction X. That is, when both the first liquid crystal panel 20A and the second liquid crystal panel 20B are not in operation (OFF), the image DSP of the display device 1 is respectively recognized from two viewpoints that are line-symmetrical in the first direction X across the viewpoint of observing the display device 1 from the front (refer to Fig. 9), the brightness of the images recognized at the two viewpoints is approximately the same. Hereinafter, when described as image DSP, it refers to the image displayed and output by the display panel 30 of the display device 1. In addition, at this time, from the viewpoint of observing the display device 1 from the front, the image can be viewed with a brightness higher than that of other viewpoints. That is, when the liquid crystal panel 20 is not in operation (OFF), the degree to which light along the third direction Z is transmitted from the liquid crystal panel 20 is greater than the degree to which light crossing the third direction Z is transmitted from the liquid crystal panel 20.

[0082] On the other hand, the liquid crystal panel 20 is Figure 6 When the operation (ON) is described, the light transmission degree is different on one side of the first direction X and on the other side of the first direction X. For the viewing angle characteristics of the display device 1 caused by the light transmission degree when the liquid crystal panel 20 is in operation (ON), refer to Figure 7 Provide explanation.

[0083] Figure 7 This is a diagram showing an example of the viewing angle characteristics of the display device 1 according to the degree of light transmission when the liquid crystal panel 20 is in operation (ON). Figure 7 The center of the concentric circles corresponds to the normal of the display device 1 along the third direction Z, and the concentric circles centered on the normal represent inclination angles of 20°, 40°, 60°, and 80° relative to the normal. The characteristic diagram shown here is obtained by connecting regions of equal transmittance for each direction.

[0084] like Figure 7 As shown, when the line of sight from the user with respect to the display device 1 is tilted toward the direction (0°) on the side of the first direction X, a relatively high light transmittance is obtained. In addition, when the line of sight from the user with respect to the display device 1 is along the normal direction, that is, when the user observes the display device 1 from the front, a relatively high light transmittance is also obtained. In contrast, when the line of sight from the user with respect to the display device 1 is tilted toward the other (180°) side of the first direction X, the light transmittance becomes significantly lower than that of one side. In particular, if the tilt angle of the line of sight to the other (180°) side of the first direction X exceeds 30°, then in Figure 7 In the example shown, the transmittance is 3% or less, and the image becomes so dark that a person cannot substantially recognize the image.

[0085] Reference Figure 7 The viewing angle characteristics described above can be used for display output control with the intention of enabling a user who views the display device 1 from the front or who wishes to view the display device 1 from one side in the first direction X to view an image, and preventing a user who wishes to view the display device 1 from the other side in the first direction X from viewing an image. For an example in which such display output control is applied, refer to Figure 8 Provide explanation.

[0086] Figure 8 This 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 the operation / non-operation (ON / OFF) of the liquid crystal panel 20 , and a user U2 who cannot view the image DSP when the liquid crystal panel 20 is in operation (ON).

[0087] like Figure 8 As shown, the display device 1 and the user U1 face each other in the third direction Z. Figure 8 The other side of the display device 1, i.e., the fifth polarizing layer 42 side is not shown in the figure. Figure 8 Therefore, the light LS1 of the image directed toward the user U1 based on the display output of 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 of observing the display device 1 from the front. On the other hand, the user U2 is at a position of obliquely observing the other side of the display device 1 from a direction inclined to the other side of the first direction X relative to the third direction Z. That is, the light LS2 of the image directed toward the user U2 based on the display output of the display device 1 is along the other side of the first direction X ( Figure 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 of viewing the display device 1 obliquely.

[0088] As Figure 8 The situation where the positional relationship between the display device 1, the user U1, and the user U2 is established is assumed to be, for example, a situation where the display device 1 is installed in a four-wheeled vehicle in which the user U2 sits in the driver's seat and the user U1 sits in the front passenger seat, but the relevant situation is not limited to this. For example, the relevant positional relationship may also be established when the display device 1 is installed as a personal display for each passenger in an aircraft such as a passenger plane, and other situations may also be included.

[0089] Fig. 9 1 is a schematic diagram showing the difference between the image DSP recognized by a user who observes the display device 1 from the front and a user who observes the display device 1 from an angle. The user who observes the display device 1 from the front is, for example, Figure 8 The user U1 in the figure. The user who observes the display device 1 obliquely is, for example, Figure 8 User U2 in reference Fig. 9In the description, the state of the display device 1 in which the display panel 30 performs image display output and the liquid crystal panel 20 is not operated (OFF) is set as the first state. In addition, the state of the display device 1 in which the display panel 30 performs image display output and the liquid crystal panel 20 is operated (ON) is set as the second state.

[0090] As described above, when the liquid crystal panel 20 is not in operation (OFF), the degree of light transmitted from the liquid crystal panel 20 along the third direction Z is greater than the degree of light transmitted from the liquid crystal panel 20 crossing the third direction Z. Figure 7 As described above, even when the liquid crystal panel 20 is in operation (ON), when the user observes the display device 1 from the front, a relatively high light transmittance is obtained. Therefore, regardless of whether the operation state of the display device 1 is the first state or the second state, the user observing the display device 1 from the front can visually recognize the display device 1. Fig. 9 The image DSP shown. It should be noted that Fig. 9 The form of the image DSP shown is just an example and the display panel 30 is not limited thereto.

[0091] On the other hand, as referenced Figure 7 As described above, when the liquid crystal panel 20 is in operation (ON), when the user's line of sight with respect to the display device 1 is tilted toward the other (180°) side of the first direction X, the transmittance of light becomes significantly lower than that of one side. Therefore, when the operation state of the display device 1 is the second state, the user who obliquely observes the display device 1 from the other side of the first direction X becomes substantially unable to recognize the image DSP. In addition, when the operation state of the display device 1 is the first state, even at the other (180°) side of the first direction X, no reference DSP is generated. Figure 7 Therefore, when the operation state of the display device 1 is the first state, even if the user obliquely observes the display device 1 from the other side of the first direction X, he can still recognize substantially the same image DSP as the user who observes the display device 1 from the front.

[0092] In addition, if Fig. 9 As shown in FIG. 1 , the image DSP is viewed as a rectangular image. That is, when the display device 1 is viewed from the front, the display area AA is Fig. 9 The image DSP shown in FIG. 1 is a rectangular shape corresponding to the image DSP. Two of the four sides of the rectangle are along the first direction X, and the other two are along the second direction Y. The dimming unit 10 of the embodiment makes the degree of transmission of the rays inclined to one side of the length direction (first direction X) of the rectangle different from the degree of transmission of the rays inclined to the other side of the length direction based on the third direction Z. Thus, the dimming unit 10 generates a reference Fig. 9 The difference in visibility between the first state and the second state is described.

[0093] In addition, as described above, the dimming unit 10 includes the first liquid crystal panel 20A set as an E-mode liquid crystal panel and the second liquid crystal panel 20B set as an O-mode liquid crystal panel. Figures 10 to 12 Provide explanation.

[0094] Fig.10 The graphs show the relationship between the polar angle and the light transmittance when the liquid crystal panel 20 is in operation (ON) for the E mode and the O mode, respectively. Fig.10 and the following Fig.14 The horizontal axis (polar angle) in the figure represents the angle along the third direction Z as the reference (0°). Figure 7 The other side of the first direction X in the description is Figure 7 The vertical axis (transmittance) represents the transmittance of the light of the ray corresponding to the polar angle shown on the horizontal axis.

[0095] like Fig.10 As shown, in the liquid crystal panel 20 (e.g., the first liquid crystal panel 20A) set as the liquid crystal panel of the E mode and the liquid crystal panel 20 (e.g., the second liquid crystal panel 20B) set as the liquid crystal panel of the O mode, the relationship between the polar angle and the transmittance of light when the liquid crystal panel 20 is in operation (ON) is different. Specifically, in the liquid crystal panel 20 set as the liquid crystal panel of the E mode, the graph showing the relationship between the polar angle and the transmittance is a deep valley-shaped graph with a polar angle of 30° as the peak and the transmittance significantly reduced to less than 1%. On the other hand, in the liquid crystal panel 20 set as the liquid crystal panel of the O mode, the graph showing the relationship between the polar angle and the transmittance is a relatively gentle basin-shaped graph compared to the E mode, such that the polar angle is approximately 1% from the polar angle of 30° to the polar angle of 40°.

[0096] By using reference Fig.10 The difference in optical characteristics between the E mode and the O mode described above can realize a more appropriate viewing angle characteristic for suppressing the image DSP from being viewed from the other side of the first direction X relative to the display device 1 in the second state. Figure 3 , Figure 4 As described, the dimming unit 10 has a liquid crystal panel 20 (for example, the first liquid crystal panel 20A) set as an E-mode liquid crystal panel and a liquid crystal panel 20 (for example, the second liquid crystal panel 20B) set as an O-mode liquid crystal panel, thereby more reliably suppressing the image DSP visible from the other side of the first direction X relative to the display device 1 in the second state.

[0097] Fig.11 and Fig.12 It is a graph showing the normalized transmittance in the display device 1 in the second state, respectively, of the E mode only, the O mode only, and the combination of the E mode and the O mode. "E mode" indicates the case where the E mode is only, that is, the dimming unit 10 has a structure of a liquid crystal panel having only the E mode. "O mode" indicates the case where the O mode is only, that is, the dimming unit 10 has a structure of a liquid crystal panel having only the O mode. "E+O mode" indicates the combination of the E mode and the O mode, that is, the case where the dimming unit 10 has a structure of a liquid crystal panel having both the E mode and the O mode as in the embodiment.

[0098] The standardized transmittance refers to the value of the brightness of the image DSP that can be viewed by the user, with the brightness of the image at the viewing angle where the brightest image can be viewed when the display device 1 is in operation being set to 1.0 and the state where there is no light from the light source 60 (when the display device 1 is not in operation) being set to 0.0, and taking a value within the range of 0.0 to 1.0.

[0099] In addition, Fig.11 and the following Fig.16 In FIG. 1 , the normalized transmittances from 0.00 to 1.00 are shown at equal intervals in the vertical direction. Fig.12 In the diagram, the upper end of the vertical axis is set to 1.0, and the value of the standardized transmittance is set to 1 / 10 each time the scale is dropped downward. Fig.11 and Fig.12 Only the expression method in the vertical axis direction is different, and the relationship between the viewing angle and the normalized transmittance represented is the same. Fig.11 and Fig.12 and the following Fig.16 The horizontal axis direction is based on the line of sight of observing the display device 1 from the front (field of view angle of 0°), and the line of sight from the angle inclined to one side of the first direction X is set to a positive (+) field of view angle, and the line of sight from the angle inclined to the other side of the first direction X is set to a negative (-) field of view angle.

[0100] Assuming that the dimming unit 10 has only an E-mode liquid crystal panel structure, the normalized transmittance is extremely close to 0 at a viewing angle of -30°, and becomes a normalized transmittance of 0.1 or more at a viewing angle on the positive (+) side compared to -20° and on the negative (-) side compared to -40°. As such, in the case of only the E-mode, there is a possibility that the image DSP can be unintentionally recognized even when the viewing angle is slightly deviated from -30° even when observed from an oblique angle.

[0101] On the other hand, when the dimming unit 10 has only an O-mode liquid crystal panel, the normalized transmittance is approximately 0.1 or more up to about -25° even when viewed from the other side of the first direction X. As described above, in the case of only the O-mode, there is a possibility that the suppression of the visual recognition from the other side of the first direction X may become insufficient.

[0102] In contrast, in the case where the dimming unit 10 has a structure of a liquid crystal panel having both E mode and O mode as in the embodiment, if the viewing angle is on the negative side compared to -20°, the normalized transmittance is significantly lower than 0.1. Moreover, even if the viewing angle is on the negative (-) side compared to -40° as in the case of only the E mode, the normalized transmittance will not be higher than 0.1. As described above, according to the embodiment, since the dimming unit 10 has a structure of a liquid crystal panel having both E mode and O mode, it is possible to more reliably suppress the visual recognition of the image DSP from the other side of the first direction X relative to the display device 1 in the second state.

[0103] In addition, in the display device 1, the specific structure of the display panel 30 that can be combined with the dimming unit 10 of the embodiment is not limited to the above-mentioned IPS type liquid crystal panel. The display panel 30 may be of other types as long as it is a so-called transmissive liquid crystal panel and has a plurality of pixels that can independently control the degree of light transmission in response to input of image data from the outside. The following is a description of the structure of the pixels in the IPS type liquid crystal panel that can be used in the display panel 30 as an embodiment, referring to Fig.13 Provide explanation.

[0104] Fig.13 FIG. 1 is a top view showing an example of a pixel layout in the display panel 30. Fig.13 , the overlap between the pixel electrodes PE1 and PE2 and the common electrode CE when viewed from the fifth polarizing layer 42 side is shown. Figure 2 The pixel electrode P is Fig.13 The pixel substrate 31 includes a plurality of scanning lines GCL and a plurality of signal lines S. The plurality of scanning lines GCL extend along the first direction X and are arranged at intervals in the second direction Y. The plurality of signal lines S extend approximately along the second direction Y and are arranged at intervals in the first direction X.

[0105] A plurality of pixel electrodes PE1 are arranged along a first direction X. The pixel electrode PE1 has a strip electrode Pa1 overlapping with a common electrode CE. The strip electrode Pa1 extends along a direction D1 different from the first direction X and the second direction Y. A plurality of pixel electrodes PE2 are arranged along the first direction X. The pixel electrode PE2 has a strip electrode Pa2 overlapping with a common electrode CE. The strip electrode Pa2 extends along a direction D2 different from the direction D1. It should be noted that the number of strip electrodes Pa1 and Pa2 may be one, or may be three or more.

[0106] Next, refer to Figures 14 to 17 The negative (-) side viewing angle control in the display device 1 operating in the second state will be described.

[0107] Fig.14 : is a diagram showing an example of the relationship between the three viewing angles Ps1, Ps2, and Ps3 on the negative (-) side and the level of the standardized transmittance. Fig.14 and the following Fig.15 In order to simplify the description, a line graph G1 is used to represent the reference Fig.11 The standardized transmittance achieved by the combination of two liquid crystal panels 20 is illustrated (eg, “E+O mode”).

[0108] For example, consider the following situation: Fig.14 The normalized transmittance shown in the graph G1 of FIG. 1 is determined assuming that the image cannot be recognized when the user corresponding to the viewing angle Ps1 is observed from an oblique angle. Here, the "user corresponding to the viewing angle Psα" refers to the user who recognizes the display device 1 from a position where the viewing angle relative to the display device 1 is the viewing angle Psα when the image displayed and output by the display device 1 is observed from an oblique angle. α is a natural number. In this case, as shown in FIG. Fig. 9 As described above, the user corresponding to the viewing angle Ps1 cannot visually recognize the image of the display device 1 operating in the second state. Fig.14 The user corresponding to the viewing angle Ps3 located on the negative (-) side of the viewing angle Ps1 cannot visually recognize the image of the display device 1 operating in the second state.

[0109] On the other hand, Fig.14 In the case of the viewing angle Ps2 which is on the positive (+) side compared to the viewing angle Ps1, the normalized transmittance becomes significantly higher than that of the viewing angle Ps1. Therefore, there is a possibility that the user corresponding to the viewing angle Ps2 can visually recognize the image.

[0110] There are various conditions related to the determination of the positional relationship between the display device 1 and the user who observes the display device 1 obliquely. Therefore, if it is assumed that the normalized transmittance of the liquid crystal panel 20 is limited to the reference Fig.14 The normalized transmittance described is sometimes for Fig.14 It cannot be said that it is foolproof for the user to suppress the recognition of the image corresponding to the field of view angle Ps2.

[0111] Therefore, in the embodiment, the voltage applied to the liquid crystal LM is controlled to control the viewing angle range in which the normalized transmittance can be reduced to a degree that can sufficiently suppress image recognition. The voltage applied to the liquid crystal LM corresponds to the potential difference between the potential of the electrode FE1 and the potential of the electrode FE2. In the following, when the reference voltage is described, it means the voltage that is equal to the reference voltage unless otherwise specified. Fig.14 The graph G1 shown is a voltage applied to the liquid crystal LM when the relationship between the normalized transmittance and the viewing angle is established.

[0112] Fig.15 : is a diagram showing an example of the relationship between the three viewing angles Ps1, Ps2, and Ps3 on the negative (-) side and the control of the normalized transmittance by controlling the applied voltage to the liquid crystal LM. Fig.15 The “positive voltage” shown means that the voltage applied to the liquid crystal LM is made higher than the reference voltage. Fig.15 The graph G2 shown shows the normalized transmittance as an example of "positive voltage". In addition, "negative voltage" means that the voltage applied to the liquid crystal LM is lower than the reference voltage. The graph G3 shows the normalized transmittance as an example of "negative voltage".

[0113] like Fig.15 As shown by the "voltage positive" of , by making the voltage applied to the liquid crystal LM higher than the reference voltage, it is possible to prevent even a user corresponding to the viewing angle Ps2 from visually recognizing the image of the display device 1 operating in the second state. Fig.15 As shown by the "voltage negative", by making the applied voltage to the liquid crystal LM lower than the reference voltage, it is possible to prevent the user corresponding to the viewing angle Ps3 from visually recognizing the image of the display device 1 operating in the second state, and to enable the user corresponding to the viewing angle Ps1 to visually recognize the image of the display device 1 operating in the second state.

[0114] Above, refer to Fig.15 The basic structure of controlling the normalized transmittance by controlling the voltage applied to the liquid crystal LM is described below. Fig.16 and Fig.17 A more detailed relationship between the voltage applied to the liquid crystal LM and the normalized transmittance will be described.

[0115] Fig.16This is a graph showing an example of each normalized transmittance when the voltage applied to the liquid crystal LM is any voltage (per 0.1 V) from 2 [V] to 2.7 [V]. Fig.17 : is a graph showing an example of the relationship between the voltage applied to the liquid crystal LM and the cut angle. Fig.17 The horizontal axis in represents the voltage applied to the liquid crystal LM. Fig.17 The cutting angle shown on the vertical axis in is the inclination angle in the first direction X relative to the display device 1 when the angle of the line of sight when observing the display device 1 from the front is set to 0 degrees (°), and is the minimum inclination angle that allows image recognition (or a state in which the image cannot be substantially recognized) at a brightness lower than the brightness of the image when observing the display device 1 from the front. For example, if the cutting angle is set to 10°, a user who views the display device 1 with a line of sight inclined by more than 10° in the first direction X relative to the line of sight (0°) when observing the display device 1 from the front will view the image at a brightness lower than the brightness of the image when observing the display device 1 from the front, or will be in a state in which the image cannot be substantially recognized. In addition, as Fig.16 As shown, in the case of the display device 1 where the viewing angle range in which the normalized transmittance becomes substantially 0 is on the negative (-) side, Fig.17 The numerical values ​​of the cut angles shown are interpreted as absolute values ​​representing negative (-) numerical values. On the contrary, in the case of the display device 1 where the viewing angle range in which the normalized transmittance becomes substantially 0 is on the positive (+) side, Fig.17 The numerical values ​​of the cut angles shown are interpreted as representing positive (+) values.

[0116] like Fig.16 As shown, the relationship between the polar angle and the standardized transmittance corresponds to the applied voltage to the liquid crystal LM. Specifically, as the applied voltage to the liquid crystal LM changes (shifts) from 2 [V] to 2.7 [V] in units of 0.1 [V], the viewing angle range where the standardized transmittance is substantially 0, the polar angle where the standardized transmittance is the lowest, the polar angle where the standardized transmittance is the highest, the relationship between the standardized transmittance and the polar angle represented by a graph of a curve between the lowest standardized transmittance and the highest standardized transmittance, and the relationship between the standardized transmittance and the polar angle represented by a graph of a curve on the positive (+) side relative to the highest standardized transmittance are all shifted (shifted) from the negative (-) side to the positive (+) side. Therefore, by setting the display device 1 to apply a voltage such that the polar angle of the viewing angle of a user (non-permitted user) who is assumed to be substantially not to recognize an image is included in the viewing angle range where the standardized transmittance is substantially 0, the non-permitted user can be prevented from recognizing an image. Furthermore, by setting the polar angle of the viewing angle of a user (permitted user) who is assumed to be able to visually recognize the image to the polar angle at which the normalized transmittance is the highest or a polar angle close thereto, the permitted user can visually recognize the image.

[0117] In addition, in reference to Fig.16 The same viewpoint is given by Fig.17 As shown, the cut angle can be adjusted according to the voltage applied to the liquid crystal LM. Therefore, by setting the polar angle between the polar angle of the viewing angle assumed to be a non-permitted user and the polar angle of the viewing angle assumed to be a permitted user as the cut angle, the viewing angle characteristics of the display device 1 that take into account both the non-permitted user and the permitted user can be achieved.

[0118] In this way, the voltage applied to the liquid crystal LM, that is, the potential difference between the electrode FE2 and the electrode FE1, corresponds to the viewing angle range in which the normalized transmittance becomes substantially 0. In fact, as described above, the viewing angle range in which the normalized transmittance becomes substantially 0, the polar angle at which the normalized transmittance is the lowest, the polar angle at which the normalized transmittance is the highest, the relationship between the normalized transmittance and the polar angle represented by a graph of a curve between the lowest normalized transmittance and the highest normalized transmittance, and the relationship between the normalized transmittance and the polar angle represented by a graph of a curve on the positive (+) side relative to the highest normalized transmittance are shifted in accordance with the change in the voltage applied to the liquid crystal LM, and the control of the applied voltage is performed with the control of the viewing angle range in which the normalized transmittance becomes substantially 0 as the main purpose.

[0119] As reference Figure 7 , Fig.14 , Fig.15 and Fig.16 As described in, etc., the dimming unit 10 uses the relative direction (third direction Z) between the display panel 30 and the light source 60 as a reference, and makes the degree of transmission of light inclined to one side (polar angle on the negative (-) side) in one direction (for example, the first direction X which is the length direction of the display panel 30) along two opposite sides of the four sides of the rectangular display panel 30 different from the degree of transmission of light inclined to the other side (polar angle on the positive (+) side). The tilted angle (polar angle at which the normalized transmittance is lowest) at which the light is transmitted the least when the dimming unit 10 is in operation, i.e., in the second state is included in either one of the one side and the other side. Here, the control of the applied voltage to the liquid crystal LM, i.e., the control of the potential difference between the electrode FE2 and the electrode FE1, is performed with the control of the viewing angle range at which the normalized transmittance becomes substantially 0 as the main purpose, and therefore, the potential difference can be said to correspond to the tilted angle at which the light transmission is lower when the liquid crystal panel 20 is in operation. In addition, as referred to Fig.16 and Fig.17As described above, the greater the potential difference, the smaller the angle of inclination at which the light transmittance is the lowest relative to the relative direction (third direction Z). In addition, the viewing angle range in which the standardized transmittance is substantially 0 can be said to be a set of viewing angles, that is, the viewing angles are the viewing angles that assume that it is difficult or impossible to recognize the image output by the display panel 30 when the liquid crystal panel 20 is operating (in the second state).

[0120] For an example of a positional relationship between the viewing angle of the display device 1 described above and a user who directs his / her line of sight toward the display device 1, refer to Fig.18 Provide explanation.

[0121] Fig.18 1 is a schematic diagram showing an example of the position angle relationship between the display device 1 and the seats SH1 and SH2 where users who are expected to view the image of the display device 1 obliquely are seated. Fig.18 In the position angle relationship between the display device 1 and the seats SH1 and SH2 shown, it is assumed that the viewing angle of the user sitting on the seat SH1 is the viewing angle θ1. In addition, it is assumed that the viewing angle of the user sitting on the seat SH2 is the viewing angle θ2. Here, if the seats SH1, SH2 and the display device 1 are provided in a vehicle such as a four-wheel vehicle, and the seat SH1 is the driver's seat of the vehicle, it is expected that the user sitting on the seat SH1 will not be able to visually recognize the image of the display device 1 during the driving of the vehicle. Therefore, by setting the display device 1 so that the applied voltage to the liquid crystal LM can include the polar angle relative to the viewing angle θ1 within the viewing angle range where the standardized transmittance becomes substantially 0, it is possible to prevent the user sitting on the seat SH1 from visually recognizing the image of the display device 1 when the display device 1 is in the second state. Furthermore, by controlling the operation of the display device 1 so as to be in the first state when the vehicle is stopped and in the second state when the vehicle is not stopped, the user sitting in the seat SH1 can be prevented from viewing the image of the display device 1 while the vehicle is driving.

[0122] Furthermore, if there is no problem in visualizing the image from the user sitting in the seat SH2 , the user sitting in the seat SH2 can also visually recognize the image on the display device 1 by setting the cut angle to between the viewing angle θ1 and the viewing angle θ2 .

[0123] The positional relationship between the display device 1 and the user who obliquely observes the image on the display device 1 is not limited to being predetermined. Fig.19 Provide explanation.

[0124] Fig.19This is a schematic diagram showing an example of a structure using cameras Ca1 and Ca2 in determining the position angle relationship between the users U21 and U22 and the display device 1. The cameras Ca1 and Ca2 include an imaging element and a circuit that generates image data based on the output of the imaging element, and function as a so-called digital camera. The imaging element is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, but is not limited thereto, and may also be another structure that functions in the same manner, such as a CCD (Charge Coupled Device) image sensor.

[0125] The camera Ca1 is arranged on the center line of the display device 1 in the first direction X, and the arrangement in the third direction Z is substantially the same as that of the display device 1. The camera Ca1 directs the viewing angle toward the display output side of the display device 1. Here, the position of the user captured within the shooting range of the camera Ca1 can be made to correspond to the field of view angle control of the display device 1. For example, it is assumed that the field of view angle of the user U22 is the field of view angle θ3. In addition, it is assumed that the field of view angle of the user U21 is the field of view angle θ4. In other words, by making a correspondence between the shooting position of the user U22 within the shooting range of the camera Ca1 and the field of view angle θ3, and making a correspondence between the shooting position of the user U21 and the field of view angle θ4, the field of view angle control of the display device 1 based on the captured image of the camera Ca1 can be realized. For example, by setting the cutting angle to between the field of view angle θ3 and the field of view angle θ4 based on the shooting result of the camera Ca1, the user U22 can not recognize the image, and the user U21 can recognize the image. Of course, the angles of view are not limited to θ3 and θ4, and other angles of view can be handled by appropriately associating the angles with the position of the user within the imaging range of the camera Ca1.

[0126] In addition, the arrangement of the camera for performing imaging for controlling the viewing angle of the display device 1 is not limited to Fig.19 The configuration of the camera Ca1 shown in the figure. For example, the camera Ca2 may be configured at a position away from the display device 1 in the first direction X. Even in this case, by establishing a correspondence between the position of the user in the shooting range and the field of view angle in advance, the field of view angle control of the display device 1 corresponding to the position of the user captured in the shooting range can be achieved. Of course, the field of view angle control may also be performed comprehensively based on the shooting results of multiple cameras (e.g., cameras Ca1 and Ca2).

[0127] The control of the voltage applied to the liquid crystal LM based on the captured image captured by the camera unit such as the cameras Ca1 and Ca2, that is, the control of the potential difference between the electrode FE2 and the electrode FE1, is performed by, for example, Fig.19The control unit 70 shown in the figure is performed. The control unit 70 includes a circuit that realizes multiple functions in its structure. The circuit is, for example, a SoC (System on a Chip), but is not limited to this, and may also include multiple chips that respectively perform different functions. The circuit performs the function of performing image processing such as pattern matching, and performing recognition of the image of the user (for example, users U21, U22) contained in the captured image obtained by the camera unit. In addition, the circuit performs the function of performing a calculation process to determine the position angle relationship between the user at the position and the display device 1 from the position of the user determined based on the image processing. In addition, the circuit has the following functions: based on the position angle relationship between the user and the display device 1 determined by the calculation process, the applied voltage to the liquid crystal LM is determined, and the display device 1 is controlled in a manner that the determined applied voltage performs the second state operation.

[0128] The camera Ca1 and the control unit 70 are connected by wiring in the display device 1. Fig.19 In the illustrated example, the camera Ca2 and the control unit 70 are connected via the wiring 71, but the captured image data may be transmitted and received via wireless communication.

[0129] exist Fig.19 In the embodiment, for the purpose of clear illustration, the control unit 70 is provided in a form protruding toward the back side of the display device 1, but the form of the control unit 70 is not limited to this. For example, a circuit that functions as the control unit 70 may be provided on a circuit substrate provided in the display device 1. Fig.19 The control unit 70 is not shown in the figure, but has a structure (such as a circuit such as SoC) having at least a function of controlling the voltage applied to the liquid crystal LM when the display device 1 operates in the second state. Fig.19 The control unit 70 shown is similarly provided in the display device 1. Fig.18 As described, when the positional relationship between the display device 1 and the user is pre-conceived, setting data representing the applied voltage to the liquid crystal LM for achieving the second state of the cutting angle corresponding to the assumption is pre-retained in the structure, and the structure controls the applied voltage to the liquid crystal LM based on the setting data.

[0130] According to the above embodiment, the display device 1 includes: a display panel 30 having a display area AA for outputting an image; a light source 60 for irradiating light toward one side of the display panel 30; a liquid crystal panel 20 interposed between the display panel 30 and the light source 60, and configured to be able to change the degree of light transmission between the display panel 30 and the light source 60; and a control unit (e.g., a control unit 70) for controlling the potential difference between two electrodes FE1 and FE2 facing each other across the liquid crystal in the liquid crystal panel 20. When the liquid crystal panel 20 is in operation, the degree of light transmission inclined to one side of the longitudinal direction (e.g., the first direction X) of the rectangular display panel 30 is different from the degree of light transmission inclined to the other side of the longitudinal direction, based on the relative direction (e.g., the third direction Z) between the display panel 30 and the light source 60. The potential difference corresponds to the angle of inclination (e.g., the polar angle on the negative (-) side) at which the degree of light transmission is lower when the liquid crystal panel 20 is in operation.

[0131] Thus, the potential difference between the two electrodes FE1 and FE2 facing each other across the liquid crystal in the liquid crystal panel 20 can be set in such a way that it is difficult or impossible for a user who recognizes the display device 1 from the following angle to recognize the image, the angle being an angle at which the light transmission degree is lower when the liquid crystal panel 20 is in operation, that is, a position angle at which it is not desirable to be able to recognize the image of the display device 1 when the liquid crystal panel 20 is in operation. Therefore, by controlling the potential difference according to the position angle relationship between the display device 1 and the user, it is possible to make it difficult or impossible for the user to recognize the image when the liquid crystal panel 20 is in operation. In this way, according to the embodiment, the viewing angle range in which the image can be recognized can be set more flexibly.

[0132] In addition, when the liquid crystal panel 20 is operating, the tilted angle at which the light transmittance is lowest is included in either one side (for example, the negative (-) side) or the other side (for example, the positive (+) side). The greater the potential difference between the two electrodes FE1 and FE2 facing each other across the liquid crystal in the liquid crystal panel 20, the smaller the tilted angle at which the light transmittance is lowest. Therefore, the viewing angle range in which it is difficult or impossible to view an image when the liquid crystal panel 20 is operating can be more flexibly controlled by controlling the potential difference.

[0133] In addition, the potential difference between the two electrodes FE1 and FE2 facing each other across the liquid crystal in the liquid crystal panel 20 corresponds to a field of view angle within the field of view angle range in which the image can be viewed when the liquid crystal panel 20 is not operating, and is intended to make it difficult or impossible to view the image when the liquid crystal panel 20 is operating. Therefore, it is possible to make it difficult or impossible for a user of the display device 1 to view the image from this field of view angle.

[0134] In addition, a camera unit (e.g., cameras Ca1, Ca2) is provided, wherein the shooting range includes the field of view angle range of the display device 1 when the liquid crystal panel 20 is not operating. The control unit (e.g., control unit 70) determines, based on the image captured by the camera unit, a field of view angle that makes it difficult or impossible to view the image when the liquid crystal panel 20 is operating. Thus, higher-precision field of view angle control corresponding to the positional angle relationship between the display device 1 and the user can be performed.

[0135] In addition, two liquid crystal panels 20 are provided, one of the two liquid crystal panels 20 (for example, the first liquid crystal panel 20A) is set as an E-mode liquid crystal panel, and the other (for example, the second liquid crystal panel 20B) is set as an O-mode liquid crystal panel, thereby achieving the display output of images that utilize the advantages of both the E-mode liquid crystal panel and the O-mode liquid crystal panel. The advantage of the E-mode liquid crystal panel is the reduction of the transmittance of steep light relative to the rays of light at a specific angle (for example, near the viewing angle of -30°). The advantage of the O-mode liquid crystal panel is the stable reduction of the transmittance of light in a larger range (for example, on the negative (-) side compared to the viewing angle of -30°). In addition, both the E-mode and the O-mode are capable of transmitting light that can fully recognize the image except for the viewing angle range where the transmittance of light is significantly reduced. In this way, according to the embodiment, while the viewing angle range where the image can be recognized and the viewing angle range where the image cannot be recognized are established at the same time, the viewing angle range where the image cannot be recognized can be more reliably ensured to be larger.

[0136] In addition, the positional relationship between the display panel (display panel 30) and the light source (light source 60), and between the E-mode liquid crystal panel and the O-mode liquid crystal panel may be opposite to that in the embodiment. In this case, it is sufficient to reverse 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. In addition, the slow axis directions V02 and V08 of the phase difference generating layers 51 and 52 are also similar, and it is sufficient to change the direction of the slow axis in a manner that is linearly symmetrical with respect to the second direction Y.

[0137] In addition, in the embodiment, the dimming unit 10 has two liquid crystal panels 20, but the number of liquid crystal panels 20 is not limited to two, and may be one, or may be three or more. In the case of a structure in which the number of liquid crystal panels 20 is different from that in the embodiment, by appropriately adding or changing optical components such as a polarization layer and a phase difference generation layer corresponding to the angle of polarized light, the light transmission path LV can be established in the same manner as in the embodiment.

[0138] In addition, regarding other effects brought about by the form described in this embodiment, effects that can be clearly seen from the description of this specification or effects that can be appropriately imagined by those skilled in the art should be understood as effects brought about by the present disclosure.

Claims

1. A display device, It is characterized in that have: A display panel having a display area for outputting an image; a light source irradiating light toward one side of the display panel; a liquid crystal panel disposed between the display panel and the light source and configured to be able to change the degree of light transmission between the display panel and the light source; as well as a control unit for controlling a potential difference between two electrodes facing each other across the liquid crystal in the liquid crystal panel, When the liquid crystal panel is in operation, the relative direction between the display panel and the light source is used as a reference, so that the degree of transmission of light inclined to one side of the length direction of the rectangular display panel is different from the degree of transmission of light inclined to the other side of the length direction. The potential difference corresponds to an inclined angle at which the light transmission degree is lower when the liquid crystal panel is operated.

2. The display device according to claim 1, It is characterized in that The tilt angle at which the light transmission degree is the lowest when the liquid crystal panel is in operation is included in one of the one side and the other side. The greater the potential difference, the smaller the angle of inclination at which the light transmission degree is the lowest.

3. The display device according to claim 1 or 2, It is characterized in that The potential difference corresponds to a viewing angle that is assumed to make it difficult or impossible to view the image when the liquid crystal panel is operating, within a viewing angle range in which the image can be viewed when the liquid crystal panel is not operating.

4. The display device according to claim 3, It is characterized in that A camera unit is provided, wherein the camera unit includes the angle of view range within the shooting range. The control unit determines, based on the image captured by the imaging unit, a viewing angle that assumes that the image will be difficult or impossible to be viewed when the liquid crystal panel is operating.

5. The display device according to claim 1 or 2, It is characterized in that The liquid crystal panel has two One of the two liquid crystal panels is set as an E-mode liquid crystal panel, and the other is set as an O-mode liquid crystal panel.

Images