Display unit

Abstract

To provide a display unit which can display an operation state of a liquid crystal panel.SOLUTION: The display unit includes: a display panel 30 having a display region for outputting an image; a light source for radiating light from one surface side of the display panel 30; a liquid crystal panel 20 arranged between the display panel 30 and the light source, the liquid crystal panel being provided to be capable of changing the degree of transmission of light between the display panel 30 and the light source; a signal generation unit 61 connected to two electrodes facing each other across the liquid crystal in the liquid crystal panel 20, the signal generation unit providing individual electric signals to two electrodes; and a signal detection unit 62 connected to the two electrodes, the signal detection unit detecting the individual electric signals provided to the two electrodes.SELECTED DRAWING: Figure 15

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] When the liquid crystal panel for light control stops working properly, it may become possible to see an image from a viewing angle range where the image output is not originally intended. It is undesirable to continue outputting an image in such a state. For this reason, there has been a demand for a mechanism for detecting the operating state of the liquid crystal panel in relation to the operational control of a display device.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and has an object to provide a display device capable of detecting the operating state of a liquid crystal panel. [Means for solving the problem]

[0006] A display device according to one embodiment of the present disclosure includes a display panel having a display area for outputting an image, a light source for irradiating light from one side of the display panel, a liquid crystal panel interposed between the display panel and the light source so as to be able to change the degree of light transmission between the display panel and the light source, a signal generation unit connected to two electrodes facing each other across the liquid crystal in the liquid crystal panel and providing individual electrical signals to each of the two electrodes, and a signal detection unit connected to the two electrodes and individually detecting the electrical signals provided to the two electrodes. [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 schematic diagram showing a signal transmission path for the electrode FE1 and a signal transmission path for the electrode FE2. [Figure 15] FIG. 15 is a block diagram showing a configuration connected to the wirings IN1, IN2, OUT1, and OUT2. [Figure 16] FIG. 16 is a graph showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the signal transmission path to the electrode FE1 and the signal transmission path to the electrode FE2 are normal. [Figure 17] FIG. 17 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off. [Figure 18] FIG. 18 is a waveform diagram showing examples of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA2 and wiring IN2 via the connection line CN2 is cut off, when the signal output path lines OUT1 and OUT2 are shorted, when the wiring IN2 and the signal output path line OUT1 are shorted, or when the wiring IN1 and the signal output path line OUT2 are shorted. [Figure 19]FIG. 19 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the connection between the signal output path line OUT1 and the terminal OP3 by the connection line CN3 is cut off. [Figure 20] FIG. 20 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off. [Figure 21] FIG. 21 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the wiring IN1 and the wiring IN2 are short-circuited. [Figure 22] FIG. 22 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the signal transmission path to the electrode FE1 and the signal transmission path to the electrode FE2 are normal. [Figure 23] FIG. 23 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off. [Figure 24] Figure 24 is a waveform diagram showing examples of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA2 and wiring IN2 via the connection line CN2 is cut off, when the connection between the signal output path line OUT2 and terminal OP4 via the connection line CN4 is cut off, when the wiring IN1 and the signal output path line OUT2 are shorted, or when the signal output path line OUT1 and the signal output path line OUT2 are shorted. [Diagram 25] FIG. 25 is a waveform diagram showing an example of inputs from the terminals OP1, OP2, OP3, and OP4 when the wiring IN1 and the wiring IN2 are short-circuited. 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] 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] 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 electrodes FE2 and 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 an area where the electrode FE2 is not formed are covered with an insulating layer 23. One surface of the electrode FE1 and one surface of the second substrate 22 in an area where the electrode FE1 is not formed are covered with an insulating layer 24. The display area AA will be described later.

[0015] At least one of the electrodes FE2 and FE1 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 electrodes FE2 and FE1 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 electrodes FE2 and FE1 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 electrodes FE2 and FE1 (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 GCL and a plurality of signal lines S. The plurality of scanning lines GCL 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 approximately 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] Next, a function relating to the operation verification of the liquid crystal panel 20 included in the display device 1 will be described. In the embodiment, a configuration is provided for checking whether a signal transmission path to the electrode FE1 and a signal transmission path to the electrode FE2 are normally established. The configuration will be described with reference to Figs. 14 to 25.

[0075] Fig. 14 is a schematic diagram showing a signal transmission path for the electrode FE1 and a signal transmission path for the electrode FE2. As shown in Fig. 14, the electrode FE1 is connected to the wiring IN1 via a conductive layer CHC1. The electrode FE1 is also connected to the signal output path line OUT1 via a conductive layer CHC2. The wiring IN1 and the signal output path line OUT1 are wirings mounted on the first substrate 21, for example.

[0076] The conductive layer CHC1 is a signal transmission path extending in the third direction Z to connect the electrode FE1 mounted on the surface of the second substrate 22 facing the first substrate 21 to the wiring IN1. The conductive layer CHC2 is a signal transmission path extending in the third direction Z to connect the electrode FE1 to the wiring IN2. The conductive layers CHC1 and CHC2 are conductive layers formed in a hole (contact hole) penetrating the liquid crystal panel 20 in the third direction Z between the electrode FE1 and the first substrate 21 shown in FIG. 2, for example.

[0077] 14, the electrode FE2 is connected to the wiring IN2 and the signal output path line OUT2. The wiring IN2 and the signal output path line OUT2 are, for example, wirings mounted on the first substrate 21. The wirings IN1, IN2, OUT1, and OUT2 may be provided on the second substrate 22. In that case, the positional relationship between the electrodes FE1 and FE2 may be interchanged.

[0078] FIG. 15 is a block diagram showing a configuration connected to wirings IN1, IN2, OUT1, and OUT2. As shown in FIG. 15, a signal generating unit 61 is connected to wirings IN1 and IN2. Specifically, the signal generating unit 61 has signal input path lines IPA1 and IPA2. The signal input path line IPA1 is connected to wiring IN1 via a connection line CN1. The signal input path line IPA2 is connected to wiring IN2 via a connection line CN2. Also, as shown in FIG. 15, a branch line IPB1 branches off from the signal input path line IPA1. Also, as shown in FIG. 15, a branch line IPB2 branches off from the signal input path line IPA2.

[0079] 15, a signal detection unit 62 is connected to the signal output path lines OUT1 and OUT2. Specifically, the signal detection unit 62 has terminals OP1, OP2, OP3, and OP4. The terminal OP1 is connected to the branch line IPB1. The terminal OP2 is connected to the branch line IPB2. The terminal OP3 is connected to the signal output path line OUT1 via a connection line CN3. The terminal OP4 is connected to the signal output path line OUT2 via a connection line CN4.

[0080] The connection lines CN1, CN2, CN3, and CN4 may be, for example, wiring provided on a flexible printed circuit board on which the signal generating unit 61, the signal detecting unit 62, and the operation control unit 63 described later are mounted, or wiring provided on a connector that connects the board on which the signal generating unit 61, the signal detecting unit 62, and the operation control unit 63 are mounted to the first board 21, or may transmit signals in other forms.

[0081] The signal generating unit 61 is a circuit that outputs a carrier wave and a constant potential. Specifically, the signal generating unit 61 outputs a carrier wave in which a fluctuation in signal strength occurs periodically from one of the signal input path line IPA1 or the signal input path line IPA2 (for example, the signal input path line IPA1). The carrier wave is, for example, a pulse signal such as a rectangular wave, but is not limited to this as long as it is a carrier wave in which a fluctuation in signal strength occurs periodically as determined in advance, and may be, for example, a sine wave. In addition, the signal generating unit 61 outputs a constant potential from the other of the signal input path line IPA1 or the signal input path line IPA2 (for example, the signal input path line IPA2). The constant potential is, for example, a ground potential, but is not limited to this, and may be a potential at which a passive electrical change occurs in the electrode FE2 as the carrier wave output from the signal input path line IPA1 is applied to the electrode FE1.

[0082] The signal detection unit 62 is a circuit that detects inputs from terminals OP1, OP2, OP3, and OP4. A carrier wave output from a signal input path line IPA1 and transmitted via a branch line IPB1 is input to the terminal OP1. A constant potential output from a signal input path line IPA2 and transmitted via a branch line IPB2 is input to the terminal OP2. An output from a signal output path line OUT1 connected to the terminal OP3 via a connection line CN3 is input to the terminal OP3. An output from a signal output path line OUT2 connected to the terminal OP4 via a connection line CN4 is input to the terminal OP4.

[0083] In this manner, the signal detection unit 62 of the embodiment is connected to a signal input path (signal input path lines IPA1, IPA2) that connects the signal generation unit 61 to two electrodes (electrodes FE1, FE2), and a signal output path (signal output path lines OUT1, OUT2) to which the two electrodes are connected and to which the signal generation unit 61 is not connected.

[0084] The output from the signal output path line OUT1 corresponds to the potential of the electrode FE1, and the output from the signal output path line OUT2 corresponds to the potential of the electrode FE2.

[0085] The signal detection unit 62 outputs to the operation control unit 63 in accordance with the inputs from the terminals OP1, OP2, OP3, and OP4. The operation control unit 63 is a circuit that controls the operation of the display panel 30.

[0086] The relationship between waveform diagrams showing examples of inputs from terminals OP1, OP2, OP3, and OP4 and the signal transmission path for electrode FE1 and the signal transmission path for electrode FE2 will be described below with reference to Figures 16 to 25. Note that the waveform diagrams shown in Figures 16 to 25 are visualizations of the potentials obtained at each of terminals OP1, OP2, OP3, and OP4 using an oscilloscope, but the potentials detected by signal detection unit 62 are also similar to the waveform diagrams.

[0087] Fig. 16 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 when the signal transmission path for electrode FE1 and the signal transmission path for electrode FE2 are normal. The waveform diagrams from Fig. 16 to Fig. 21 are waveform diagrams in the case where a square wave from the signal generating unit 61 is input to wiring IN1 and applied to the electrode FE1, and a ground potential from the signal generating unit 61 is input to wiring IN2 and applied to the electrode FE2. That is, when the waveform diagrams from Fig. 16 to Fig. 21 are obtained, a square wave is output from the signal input path line IPA1 of the signal generating unit 61, and a ground potential is output from the signal input path line IPA2.

[0088] Note that a case where a rectangular wave is output from one of the signal input path line IPA1 or the signal input path line IPA2 of the signal generating unit 61 and a ground potential is output from the other is, for example, a case where the liquid crystal panel 20 is operating (ON). In the embodiment, when the liquid crystal panel 20 is not operating (OFF), the electrical signal output to the signal input path line IPA1 and the electrical signal output to the signal input path line IPA2 are the same.

[0089] As described above, when a square wave is output from the signal input path line IPA1 of the signal generating unit 61, the square wave is transmitted to the terminal OP1 via the branch line IPB1. Therefore, as shown in FIG. 16, a square wave appears as a detection result at the terminal OP1. FIG. 16 shows that a square wave that rises from a low level (L) to a high level (H) at a timing Ta and falls from a high level (H) to a low level (L) at a timing Tb after the timing Ta is input to the terminal OP1. Furthermore, when a ground potential is output from the signal input path line IPA2, the ground potential is transmitted to the terminal OP2 via the branch line IPB2. Therefore, as shown in FIG. 16, a ground potential G is detected at the terminal OP2.

[0090] In addition, the square wave output from the signal input path line IPA1 is transmitted to the electrode FE1 via the connection line CN1, the wiring IN1, and the conductive layer CHC1, and is transmitted from the electrode FE1 to the terminal OP3 via the conductive layer CHC2, the signal output path line OUT1, and the connection line CN3. Therefore, as shown in Fig. 16, a square wave similar to that of the terminal OP1 appears as a detection result at the terminal OP3.

[0091] Also, the ground potential output from the signal input path line IPA2 is transmitted to the electrode FE2 via the connection line CN2 and the wiring IN2. Therefore, the potential of the electrode FE2 is kept at the potential L2 corresponding to the ground potential for most of the period. However, as the potential of the electrode FE1 rises from a low level (L) to a high level (H) at the timing Ta, the potential of the electrode FE2 also rises temporarily to a potential L1 higher than the ground potential, and then immediately returns to the potential L2. In FIG. 16, the potential change from the potential L2 to the potential L1 and then immediately returns to the potential L2 is shown as a potential change PU1. Also, as the potential of the electrode FE1 rises from a high level (H) to a low level (L) at the timing Tb, the potential of the electrode FE2 also falls temporarily to a potential L3 lower than the ground potential, and then immediately returns to the potential L2. In FIG. 16, the potential change from the potential L2 to the potential L3 and then immediately returns to the potential L2 is shown as a potential change PD1. The potential of the electrode FE2, including the changes shown as potential change PU1 and potential change PD1, is transmitted to the terminal OP4 via the signal output path line OUT2 and the connection line CN4. Therefore, as shown in Fig. 16, the terminal OP4 is maintained at potential L2 corresponding to the ground potential for most of the period as a detection result, but a potential transition pattern including changes such as potential change PU1 at timing Ta and potential change PD1 at timing Tb appears.

[0092] Above, examples of inputs from terminals OP1, OP2, OP3, and OP4 when the signal transmission path to electrode FE1 and the signal transmission path to electrode FE2 are normal, that is, when the signal transmission path shown in Fig. 15 is normally established, have been described with reference to Fig. 16, but if the signal transmission path becomes in a state different from that shown in Fig. 15 for some reason, the inputs from terminals OP1, OP2, OP3, and OP4 will also be different from those shown in Fig. 16. Below, examples of inputs from terminals OP1, OP2, OP3, and OP4 different from those shown in Fig. 16 will be described with reference to Figs. 17 to 21.

[0093] FIG. 17 is a waveform diagram showing an example of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off. Even if the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off, the input to the terminal OP1 via the branch line IPB1 branching off from the signal input path line IPA1 is the same as that described with reference to FIG. 16. Therefore, as shown in FIG. 17, a square wave appears as a detection result at the terminal OP1. Also, even if the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off, the input to the terminal OP2 is the same as that described with reference to FIG. 16. Therefore, as shown in FIG. 17, the ground potential G is detected at the terminal OP2.

[0094] On the other hand, when the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off, the square wave output from the signal input path line IPA1 is not transmitted to the electrode FE1. Therefore, unlike the case described with reference to FIG. 16, the detection result at the terminal OP3 does not show a square wave. In this case, a constant potential is continuously detected at the terminal OP3 as shown in FIG. 17. Also, in this case, the potential of the electrode FE2 does not change in conjunction with the rise and fall of the potential of the electrode FE1. Therefore, unlike the case described with reference to FIG. 16, the detection result at the terminal OP4 does not show a potential transition pattern in which the potential changes to a potential deviating from the potential L2 (potential L1 or potential L3). In this case, a constant potential is continuously detected at the terminal OP4 as shown in FIG. 17.

[0095] 18 to 21, the description of the same detection results as in Fig. 16 will basically be omitted, and the description will focus on detection results that differ from Fig. 16. Note that, even for detection results similar to Fig. 16, supplementary explanations will be provided in cases where there are noteworthy points.

[0096] 18 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 in the case where the connection between the signal input path line IPA2 and the wiring IN2 by the connection line CN2 is cut off, the signal output path line OUT1 and the signal output path line OUT2 are shorted, the wiring IN2 and the signal output path line OUT1 are shorted, or the wiring IN1 and the signal output path line OUT2 are shorted. When the connection between the signal input path line IPA2 and the wiring IN2 by the connection line CN2 is cut off, the ground potential output from the signal input path line IPA2 is not transmitted to the electrode FE2. In this case, the potential of the electrode FE2 fluctuates in conjunction with the change in potential due to the square wave transmitted to the electrode FE1. Therefore, in this case, a square wave similar to that of the terminal OP3 appears as a detection result at the terminal OP4.

[0097] Also, when the signal output path line OUT1 and the signal output path line OUT2 are shorted, a detection result similar to the detection result at the terminal OP1 also appears at the terminal OP4. When the wiring IN1 and the signal output path line OUT2 are shorted, a detection result similar to the detection result at the terminal OP3 also appears at the terminal OP4. When the wiring IN2 and the signal output path line OUT1 are shorted, a signal similar to the signal transmitted from the signal output path line OUT1 to the terminal OP3 via the connection between the wiring IN2 and the signal output path line OUT1 is transmitted to the terminal OP4 via the wiring IN2, the electrode FE2, the signal output path line OUT2, and the connection line CN4. That is, in this case as well, a detection result similar to the detection result at the terminal OP3 also appears at the terminal OP4. Therefore, in either of these cases, a square wave appears as the detection result at the terminal OP4, as shown in FIG. 18.

[0098] 19 is a waveform diagram showing an example of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal output path line OUT1 and the terminal OP3 by the connection line CN3 is cut off. When the connection between the signal output path line OUT1 and the terminal OP3 by the connection line CN3 is cut off, the change in potential occurring at the electrode FE1 is no longer transmitted to the terminal OP3. Therefore, in this case, a constant potential continues to be detected at the terminal OP3 as shown in FIG.

[0099] On the other hand, since there is no problem with the connection between the signal input path line IPA1 and the wiring IN1 and the rectangular wave output from the signal input path line IPA1 is transmitted to the electrode FE1, the change in the potential of the electrode FE2 in response to the rise in the potential of the electrode FE1 at timing Ta (potential change PU1) and the change in the potential of the electrode FE2 in response to the fall in the potential of the electrode FE1 at timing Tb (potential change PD1) occur in the same manner as in the case described with reference to Fig. 16. Therefore, even in this case, the detection result at the terminal OP4 is the same as the detection result described with reference to Fig. 16.

[0100] In other words, in the example shown in Fig. 19, the change in potential occurring at the electrode FE1 is simply not transmitted to the terminal OP3, and the change in potential at the electrodes FE1 and FE2 due to the transmission of a rectangular wave to the electrode FE1 occurs in the same manner as in the case described with reference to Fig. 16. That is, as far as the input of a signal from the signal generating unit 61 to the liquid crystal panel 20 is concerned, even in the case described with reference to Fig. 19, the signal transmission path functions in the same manner as in the example described with reference to Fig. 16.

[0101] 20 is a waveform diagram showing an example of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off. When the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off, the change in potential occurring at the electrode FE2 is no longer transmitted to the terminal OP4. Therefore, in this case, a constant potential continues to be detected at the terminal OP4 as shown in FIG.

[0102] Furthermore, if there is no problem with the connection between the signal input path line IPA2 and the wiring IN2, and the ground potential output from the signal input path line IPA2 is transmitted to the electrode FE2, even in the case described with reference to Figure 20, the transition pattern of the potential of the electrode FE2 will be the same as that described with reference to Figure 16.

[0103] However, in the example shown in Figure 20, it cannot be completely denied that there may actually be a change in the potential of electrode FE2 similar to that described with reference to Figure 18, and therefore, unlike the case described with reference to Figure 19, it is considered difficult to completely deny that signals are being correctly input to electrodes FE1 and FE2 of liquid crystal panel 20.

[0104] FIG. 21 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 when the wiring IN1 and the wiring IN2 are shorted. When the wiring IN1 and the wiring IN2 are shorted, the degree of change in the potential of the electrode FE1 due to the square wave transmitted from the signal input path line IPA1 to the wiring IN1 becomes small. Therefore, as shown in FIG. 21, the upper and lower peaks of the square wave in the detection result at the terminals OP1 and OP3 do not reach the high level (H) and the low level (L). In other words, when a square wave whose upper and lower peaks do not reach the high level (H) and the low level (L) appears as the detection result at the terminals OP1 and OP3 as shown in FIG. 21, it can be estimated that the wiring IN1 and the wiring IN2 are shorted and there is a high possibility that a problem has occurred in the signal transmission path related to the input of a signal to the electrodes FE1 and FE2.

[0105] The operation control unit 63 controls the operation of the display panel 30 based on the detection result of the electrical signal by the signal detection unit 62. Specifically, the operation control unit 63 determines whether the liquid crystal panel 20 is operating normally based on the electrical signal detected in the signal input path (signal input path lines IPA1, IPA2) and the electrical signal detected in the signal output path (signal output path lines OUT1, OUT2).

[0106] More specifically, when any of the examples of Figures 16 to 21 is detected by the signal detection unit 62, the operation control unit 63 determines that the liquid crystal panel 20 is operating normally when the detection results of the terminals OP1, OP2, OP3, and OP4 shown in Figure 16 are obtained. On the other hand, the operation control unit 63 determines that the liquid crystal panel 20 is not operating normally when the detection results of the terminals OP1, OP2, OP3, and OP4 shown in any of Figures 17 to 21 are obtained.

[0107] The operation control unit 63 causes the display panel 30 to output an image when it is determined that the liquid crystal panel 20 is operating normally, and causes the display panel 30 to stop outputting an image when it is determined that the liquid crystal panel 20 is not operating normally.

[0108] The case where a square wave, which is an example of a carrier wave, is output from the signal input path line IPA1 and a ground potential, which is an example of a constant potential, is output from the signal input path line IPA2 has been described above with reference to Figures 16 to 21. Below, a case where a square wave, which is an example of a carrier wave, is output from the signal input path line IPA2 and a ground potential, which is an example of a constant potential, is output from the signal input path line IPA1 will be described with reference to Figures 22 to 25.

[0109] Fig. 22 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 when the signal transmission path for electrode FE1 and the signal transmission path for electrode FE2 are normal. The waveform diagrams from Fig. 22 to Fig. 25 are waveform diagrams when a rectangular wave from signal generating unit 61 is input to wiring IN2 and applied to electrode FE2, and a ground potential from signal generating unit 61 is input to wiring IN1 and applied to electrode FE1.

[0110] As described above, when a square wave is output from the signal input path line IPA2 of the signal generating unit 61, the square wave is transmitted to the terminal OP2 via the branch line IPB1. Therefore, as shown in FIG. 22, a square wave appears as a detection result at the terminal OP2. FIG. 22 shows that a square wave that falls from a high level (H) to a low level (L) at a timing Tc and rises from a low level (L) to a high level (H) at a timing Td is input to the terminal OP2. Furthermore, when a ground potential is output from the signal input path line IPA1, the ground potential is transmitted to the terminal OP1 via the branch line IPB1. Therefore, as shown in FIG. 22, a ground potential G is detected at the terminal OP1.

[0111] In addition, the ground potential output from the signal input path line IPA1 is transmitted to the electrode FE1 via the connection line CN1, the wiring IN1, and the conductive layer CHC1, and is transmitted from the electrode FE1 to the terminal OP3 via the conductive layer CHC2, the signal output path line OUT1, and the connection line CN3. Therefore, as shown in Fig. 22, a constant potential square wave similar to that of the terminal OP1 appears as a detection result at the terminal OP3.

[0112] In addition, the square wave output from the signal input path line IPA2 is transmitted to the electrode FE2 via the connection line CN2 and the wiring IN2, and is transmitted from the electrode FE2 to the terminal OP4 via the signal output path line OUT2 and the connection line CN4. Therefore, as shown in Fig. 22, the ground potential G is detected at the terminal OP4, similar to that at the terminal OP2.

[0113] Thus far, examples of inputs from terminals OP1, OP2, OP3, and OP4 have been described with reference to Fig. 22 when the signal transmission path to electrode FE1 and the signal transmission path to electrode FE2 are normal, that is, when the signal transmission path shown in Fig. 15 is normally established, but if the signal transmission path becomes in a state different from that shown in Fig. 15 for some reason, the inputs from terminals OP1, OP2, OP3, and OP4 will also be different from those shown in Fig. 22. Below, examples of inputs from terminals OP1, OP2, OP3, and OP4 different from those shown in Fig. 22 will be described with reference to Figs. 23 to 25.

[0114] 23 to 25, the description of the same detection results as in Fig. 22 will basically be omitted, and only the detection results different from Fig. 22 will be described. Note that, even for the detection results similar to those in Fig. 22, supplementary explanations will be given regarding any notable points.

[0115] 23 is a waveform diagram showing an example of inputs from terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off. When the connection between the signal input path line IPA1 and the wiring IN1 by the connection line CN1 is cut off, the ground potential output from the signal input path line IPA1 is not transmitted to the electrode FE1. In this case, the potential of the electrode FE1 fluctuates in conjunction with the change in potential due to the square wave transmitted to the electrode FE1. Therefore, in this case, a square wave similar to that of the terminal OP4 appears as a detection result at the terminal OP3.

[0116] 24 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 when the connection between the signal input path line IPA2 and the wiring IN2 by the connection line CN2 is cut off, when the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off, when the wiring IN1 and the signal output path line OUT2 are shorted, or when the signal output path line OUT1 and the signal output path line OUT2 are shorted. When the connection between the signal input path line IPA2 and the wiring IN2 by the connection line CN2 is cut off, the square wave output from the signal input path line IPA2 is not transmitted to the electrode FE2. Also, when the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off, the change in potential occurring at the electrode FE2 is not transmitted to the terminal OP4. Also, when the wiring IN1 and the signal output path line OUT2 are shorted, the ground potential input from the wiring IN1 to the electrode FE1 through the connection between the wiring IN1 and the signal output path line OUT2 is transmitted to the terminal OP4 through the signal output path line OUT2 and the connection line CN4. At this time, a path (ground path) to the ground potential is also established for the electrode FE2 through the signal output path line OUT2. Even when the signal output path line OUT1 and the signal output path line OUT2 are shorted, the potential state of the electrode FE2 and the terminal OP4 is the same as when the wiring IN1 and the signal output path line OUT2 are shorted. Therefore, in these cases, unlike the case described with reference to FIG. 22, the detection result at the terminal OP4 does not show a square wave. In this case, a constant potential continues to be detected at the terminal OP4 as shown in FIG. 24.

[0117] Of the various cases described with reference to Fig. 24, only when the connection between the signal output path line OUT2 and the terminal OP4 by the connection line CN4 is cut off, the change in potential occurring at the electrode FE2 is not transmitted to the terminal OP4, and the change in potential of the electrodes FE1 and FE2 occurs in the same manner as in the case described with reference to Fig. 22. However, in other cases, the change in potential of the electrodes FE1 and FE2 differs from the case described with reference to Fig. 22. Therefore, when an input similar to the waveform diagram shown in Fig. 24 is obtained from the terminals OP1, OP2, OP3, and OP4, it is desirable to consider that the signal generating unit 61 is not necessarily operating normally and that there is a possibility of an abnormality.

[0118] FIG. 25 is a waveform diagram showing an example of input from terminals OP1, OP2, OP3, and OP4 when the wiring IN1 and the wiring IN2 are shorted. When the wiring IN1 and the wiring IN2 are shorted, the degree of change in the potential of the electrode FE2 due to the square wave transmitted from the signal input path line IPA2 to the wiring IN2 becomes small. Therefore, as shown in FIG. 25, the upper and lower peaks of the square wave in the detection result at the terminals OP2 and OP4 do not reach the high level (H) and the low level (L). In other words, when a square wave whose upper and lower peaks do not reach the high level (H) and the low level (L) appears as the detection result at the terminals OP2 and OP4 as shown in FIG. 25, it can be estimated that the wiring IN1 and the wiring IN2 are shorted and there is a high possibility that a problem has occurred in the signal transmission path related to the input of a signal to the electrodes FE1 and FE2.

[0119] Even when the connection between the signal output path line OUT1 and the terminal OP3 by the connection line CN3 is cut, inputs can be obtained from the terminals OP1, OP2, OP3, and OP4 similar to those in Fig. 22. However, if the connection between the signal output path line OUT1 and the terminal OP3 by the connection line CN3 is simply cut, it can be said that the signal transmission path functions in the same manner as the example described with reference to Fig. 22, as far as the input of a signal from the signal generating unit 61 to the liquid crystal panel 20 is concerned.

[0120] When any of the examples of Figures 22 to 25 is detected by the signal detection unit 62, the operation control unit 63 determines that the liquid crystal panel 20 is operating normally when the detection results of the terminals OP1, OP2, OP3, and OP4 shown in Figure 22 are obtained. On the other hand, the operation control unit 63 determines that the liquid crystal panel 20 is not operating normally when the detection results of the terminals OP1, OP2, OP3, and OP4 shown in any of Figures 23 to 25 are obtained.

[0121] As described above, according to the embodiment, 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, a liquid crystal panel (liquid crystal panel 20) 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, a signal generating unit (signal generating unit 61) connected to two electrodes (electrodes FE1, FE2) facing each other across a liquid crystal (liquid crystal LM) in the liquid crystal panel and providing individual electric signals to each of the two electrodes, and a signal detecting unit (signal detecting unit 62) connected to the two electrodes and detecting the electric signals provided to the two electrodes individually. That is, the signal detecting unit can detect whether the electric signals to be provided are provided to the two electrodes, and information regarding the validity of the signal transmission path of the electric signals provided to the two electrodes in accordance with the operation of the liquid crystal panel can be obtained. Thus, according to the embodiment, the operating state of the liquid crystal panel (liquid crystal panel 20) can be detected.

[0122] In addition, by providing an operation control unit (operation control unit 63) that determines whether the liquid crystal panel (liquid crystal panel 20) is operating normally based on an electrical signal detected in the signal input path (signal input path lines IPA1, IPA2) and an electrical signal detected in the signal output path (signal output path lines OUT1, OUT2), it is possible to determine whether the liquid crystal panel is operating normally or whether some abnormality has occurred.

[0123] In addition, a signal detection unit (signal detection unit 62) is connected to a signal input path (signal input path lines IPA1, IPA2) connecting the signal generation unit (signal generation unit 61) and two electrodes (electrodes FE1, FE2), and a signal output path (signal output path lines OUT1, OUT2) to which the two electrodes are connected and to which the signal generation unit 61 is not connected, and an operation control unit (operation control unit 63) causes the display panel (display panel 30) to output an image when it is determined that the liquid crystal panel (liquid crystal panel 20) is operating normally, and stops the output of an image by the display panel when it is determined that the liquid crystal panel is not operating normally, thereby outputting an image only when the liquid crystal panel is normal, and not outputting an image when the liquid crystal panel is abnormal.

[0124] Therefore, for example, in the case where the display device (display device 1) is installed in a four-wheeled vehicle, if it is determined that the liquid crystal panel (liquid crystal panel 20) is not operating normally during an operation intended to output an image that allows a certain user (e.g., user U1) to view the image and prevents another user (e.g., user U2) from viewing the image, the output of the image can be stopped. In other words, it is possible to prevent the occurrence of a situation in which the other user unintentionally becomes able to view the image. This makes it possible to prevent the occurrence of unintended situations, such as when the other user is the driver of the four-wheeled vehicle, in which the other user unintentionally becomes able to view the image while driving and loses attention.

[0125] Moreover, by providing one of the two liquid crystal panels 20 (for example, the first liquid crystal panel 20A) as an E-mode liquid crystal panel and the other (for example, the second liquid crystal panel 20B) as an O-mode liquid crystal panel, it is possible to realize an image display output utilizing both the advantages of the E-mode liquid crystal panel and the advantages of 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. Thus, according to the embodiment, it is possible to simultaneously establish a viewing angle range in which an image is viewable and a viewing angle range in which an image is not viewable, while more reliably securing a viewing angle range in which an image is not viewable.

[0126] Furthermore, during operation, the liquid crystal panel 20 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.

[0127] 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.

[0128] In addition, in the embodiment, the light control 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 three or more. When a configuration in which the number of liquid crystal panels 20 is different from that in the embodiment is adopted, the light transmission path LV can be established similarly to the embodiment by appropriately adding or changing optical members such as a polarizing layer and a phase difference generating layer according to the angle of polarization.

[0129] 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]

[0130] 1 Display device 10. Dimming section 20 Liquid crystal panel 20A 1st LCD panel 20B Second LCD panel 23a, 24a Alignment film 30 Display Panel 60 light source 61 Signal Generator 62 Signal detection unit 63 Motion control section FE1,FE2 electrode

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 liquid crystal panel interposed between the display panel and the light source so as to be capable of changing a degree of light transmission between the display panel and the light source; a signal generating section connected to two electrodes that face each other across the liquid crystal in the liquid crystal panel and that supplies individual electric signals to the two electrodes; A signal detection unit connected to the two electrodes and detecting the electrical signals applied to the two electrodes individually. Display device.

2. an operation control unit that controls an operation of the display panel based on a detection result of the electrical signal by the signal detection unit; The display device according to claim 1 .

3. the signal detection unit is connected to a signal input path that connects the signal generation unit and the two electrodes, and a signal output path to which the two electrodes are connected and to which the signal generation unit is not connected; The operation control unit is determining whether the liquid crystal panel is operating normally based on the electrical signal detected in the signal input path and the electrical signal detected in the signal output path; outputting an image on the display panel when it is determined that the liquid crystal panel is operating normally, and stopping the output of an image by the display panel when it is determined that the liquid crystal panel is not operating normally. The display device according to claim 2 .

4. The liquid crystal panel is provided with two One of the two liquid crystal panels is provided as an E-mode liquid crystal panel, and the other is provided as an O-mode liquid crystal panel. The display device according to claim 1 .

5. During operation, the liquid crystal panel differentiates a degree of light transmission inclined toward one side in a longitudinal direction of the rectangular display panel from a degree of light transmission inclined toward 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