Display device

Abstract

To provide a display device which can detect the operation state of a liquid crystal panel.SOLUTION: A display device 1 includes: a display panel 30 having a display region AA for outputting an image; a light source 60 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 60, the liquid crystal panel being capable of changing the degree of transmission of light between the display panel 30 and the light source 60; a temperature detection unit for detecting the temperature of at least one of the display panel 30 and the liquid crystal panel 20; and a control unit for adjusting a regeneration color by the display panel 30 according to the temperature detected by the temperature detection unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

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

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

[0004] Liquid crystals have a tendency for the response characteristics of liquid crystal molecules to change with temperature when voltage is applied, which means that the chromaticity of the reproduced colors in the display output tends to change depending on the temperature of the display device, resulting in unstable display output quality.

[0005] The present disclosure has been made in consideration of the above problems, and has an object to provide a display device that can suppress changes in display output due to temperature changes. [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 an example of the configuration of a temperature detection panel. [Figure 15] FIG. 15 is a schematic diagram showing an example of the configuration of a temperature detection panel. [Figure 16] FIG. 16 is a diagram showing the positional relationship between the display area and the variable resistor, and a schematic shape of the variable resistor. [Figure 17] FIG. 17 is an enlarged view of a portion CU1 in FIG. [Figure 18] FIG. 18 is an enlarged view of a portion CU2 in FIG. [Figure 19] FIG. 19 is a schematic block diagram showing the relationship between the circuit configuration of a temperature sensor, the circuit configuration of a temperature detection unit including the temperature sensor, and control based on the output from the temperature detection unit. [Figure 20] FIG. 20 is a diagram showing a schematic shape of a temperature detection section when a temperature detection resistive element is disposed inside a display area. [Figure 21] FIG. 21 is a graph showing the VT characteristics of a display panel. [Figure 22] FIG. 22 is an xy chromaticity diagram showing the relationship between the temperature of the display panel and the chromaticity of the colors reproduced by the display output of the display panel. [Diagram 23] FIG. 23 is a graph showing the VT characteristics of a liquid crystal panel. [Figure 24] FIG. 24 is an xy chromaticity diagram showing the relationship between the temperature of the display device and the chromaticity of the color reproduced by the display output of the display device. 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, the temperature detection function of the display device 1 will be described with reference to FIGS.

[0075] 14 and 15 are schematic diagrams showing a configuration example of the temperature detection panel PNL. The temperature detection panel PNL is the liquid crystal panel 20 or the display panel 30. When the temperature detection panel PNL is the liquid crystal panel 20, the first panel PNL1 is the first substrate 21, and the second panel PNL2 is the second substrate 22. When the temperature detection panel PNL is the display panel 30, the first panel PNL1 is the pixel substrate 31, and the second panel PNL2 is the counter substrate 32.

[0076] The frame area GA is a frame area that does not substantially transmit light, and is an area where the seals 25 and 36 described with reference to Fig. 2 are provided. Note that the frame area GA in Fig. 15 is intentionally illustrated thinly in order to clearly illustrate the first frame portion SL1, the second frame portion SL2, the third frame portion SLA3, and the fourth frame portion SLA4 that overlap with the frame area GA in the third direction Z, and does not reflect the actual thickness.

[0077] The temperature detection panel PNL includes a temperature sensor unit SENS (see FIG. 19). The temperature sensor unit SENS is provided in at least one of the first frame unit SL1, the second frame unit SL2, the first display area interior SA1, the second display area interior SA2, and the third display area interior SA3 shown in FIG. 14, and the third frame unit SLA3 and the fourth frame unit SLA4 shown in FIG.

[0078] The display area interior SA shown in Fig. 15 is an example of the first display area interior SA1, the second display area interior SA2, and the third display area interior SA3 when viewed from the third direction Z. As shown in Fig. 15, the display area interior SA is located within the display area AA. As shown in Fig. 14, the first display area interior SA1 is one side of the first panel PNL1. The second display area interior SA2 is the other side of the first panel PNL1. The third display area interior SA3 is the other side of the second panel PNL2.

[0079] As shown in FIG. 15, the first frame portion SL1, the second frame portion SL2, the third frame portion SLA3, and the fourth frame portion SLA4 are arranged along one of the four sides forming the rectangular outer edge of the display area AA when the XY plane is viewed from the front, and the sides along which the first frame portion SL1, the second frame portion SL2, the third frame portion SLA3, and the fourth frame portion SLA4 are arranged are different from each other. The first frame portion SL1, the second frame portion SL2, the third frame portion SLA3, and the fourth frame portion SLA4 form a rectangular frame that contains the display area AA inside. As shown in FIG. 14, the configuration of the temperature sensor portion SENS provided in the first frame portion SL1 and the second frame portion SL2 (for example, variable resistors ER1 and ER2 described later) is formed on the other side of the first panel PNL1. Although not shown in FIG. 14, the configuration of the temperature sensor portion SENS provided in the third frame portion SLA3 and the fourth frame portion SLA4 is also formed on the same surface as the first frame portion SL1 and the second frame portion SL2.

[0080] The second frame portion SL2 is located on the end side of the first panel PNL1 in the second direction Y where wiring (e.g., an FPC, etc.) connecting the temperature detection panel PNL to an external circuit or information processing device is connected, and the first frame portion SL1 is located on the opposite side.

[0081] The temperature sensor unit SENS will be described in more detail below. First, a configuration example in which the variable resistor included in the temperature sensor unit SENS is provided in the first frame portion SL1, the fourth frame portion SLA4, and the second frame portion SL2 will be described with reference to FIGS.

[0082] 16 is a diagram showing the positional relationship between the display area AA and the variable resistors ER1 and ER2, and the schematic shapes of the variable resistors ER1 and ER2. The variable resistors ER1 and ER2 are components of a temperature detection unit provided in the first frame portion SL1, the fourth frame portion SLA4, and the second frame portion SL2. Specifically, the variable resistors ER1 and ER2 are conductors arranged at a distance from each other across a separation portion Sep in the second frame portion SL2. That is, the variable resistors ER1 and ER2 are electrically independent of each other. The separation portion Sep is a range in the second frame portion SL2 where neither the variable resistor ER1 nor the variable resistor ER2 extends.

[0083] The variable resistor ER1 is a structure in which a conductor extending in the first direction X in the first frame portion SL1, a conductor extending in the second direction Y in the fourth frame portion SLA4, and a conductor extending in the first direction X on one side of the separation portion Sep in the second frame portion SL2 in the first direction X are continuous. The variable resistor ER2 is a conductor extending in the first direction X on the other side of the separation portion Sep in the second frame portion SL2 in the first direction X. The conductor constituting the variable resistors ER1 and ER2 is, for example, copper, but is not limited thereto and may be other metals, alloys, compounds, or other conductors.

[0084] Fig. 17 is an enlarged view of a portion CU1 in Fig. 16. As shown in Fig. 17, the variable resistor ER1 is a lattice-shaped conductor. The lattice holes Gap1 of the variable resistor ER1 shown in Fig. 17 are rectangular in shape with their longitudinal direction aligned with the first direction X, but are not limited thereto and may have other shapes.

[0085] Fig. 18 is an enlarged view of a portion CU2 in Fig. 16. As shown in Fig. 18, the variable resistor ER2 is a ladder-shaped conductor that continues around the gap Gap2. The gap of the ladder has a shape similar to that of the lattice hole Gap1 shown in Fig. 17, but may have a different shape.

[0086] 16, the variable resistor ER1 has an input terminal Vin1 and an output terminal Vout1 that extend in the second direction Y near the separated part Sep. The variable resistor ER2 has an input terminal Vin2 and an output terminal Vout2 that extend in the second direction Y near the separated part Sep.

[0087] The electric resistance value of each of the variable resistors ER1 and ER2 corresponds to the temperature of each of the variable resistors ER1 and ER2. Therefore, the temperature of the temperature detection panel PNL in which the variable resistors ER1 and ER2 are provided can be detected based on the electric resistance values ​​of the variable resistors ER1 and ER2. Hereinafter, when simply referring to the resistance value, it refers to the electric resistance value unless otherwise specified. The mechanism of temperature detection based on the resistance value will be described with reference to FIG. 19.

[0088] 19 is a schematic block diagram showing the relationship between the circuit configuration of the temperature sensor SENS(m), the circuit configuration of a temperature detection unit 100 including the temperature sensor SENS(m), and control based on the output from the temperature detection unit 100. As shown in FIG. 19, the temperature detection unit 100 includes a temperature sensor SENS(m), a storage unit 80, and a temperature detection circuit 90.

[0089] 19, the temperature sensor SENS(m) is configured by electrically connecting a reference resistor 71 and a temperature detection resistor element ER(m) in series between an input potential Vin input from a temperature detection circuit 90 and a reference potential GND. The temperature sensor SENS(m) outputs an output potential Vout(m) according to the volume resistivity of the temperature detection resistor element ER(m). In other words, the potential at the connection point between the temperature detection resistor element ER(m) and the reference resistor 71 is output as the output potential Vout(m) of the temperature sensor SENS(m).

[0090] In the temperature sensor SENS(m), a current generated according to the input potential Vin attempts to flow to the reference potential GND, but the flow of the current to the reference potential GND is blocked according to the volume resistivity of the temperature detection resistor element ER(m), so that a current flows toward the temperature detection circuit 90. This current flowing toward the temperature detection circuit 90 generates an output potential Vout(m). That is, the higher the volume resistivity of the temperature detection resistor element ER(m), the higher the output potential Vout(m). In other words, the output potential Vout(m) reflects the electrical resistance value of the temperature detection resistor element ER(m) according to the temperature.

[0091] If the resistance value of the reference resistor 71 is Rref and the resistance value of the temperature detection resistive element ER(m) is Re(m), the output potential Vout(m) of the temperature sensor SENS(m) is expressed by the following formula (1).

[0092] Vout(m)=[Re(m) / {Re(m)+Rref}]×Vin...(1)

[0093] At this time, the temperature TPA(m) detected by the temperature sensor SENS(m) is expressed by the following formula (2).

[0094] TPA(m)=[Rref / {(Vin / Vout(m))-1}]×a(m)+b(m)...(2)

[0095] In the above formula (2), the first coefficient a(m) and the second coefficient b(m) are inherent values ​​for compensating for electrical characteristic variations of the temperature detection resistor element ER(m), and are different values ​​for each temperature detection resistor element ER(m). Therefore, when calculating the temperature of each partial temperature detection area PA detected by the temperature sensor SENS(m), the temperature detection circuit 90 needs to apply different first coefficients a(m) and second coefficients b(m) to each temperature detection resistor element ER(m) of the temperature sensor SENS(m), in other words, to each output potential Vout(m) output from each partial temperature detection area PA.

[0096] The variable resistors ER1 and ER2 described with reference to Fig. 16 to Fig. 18 function as temperature detection resistance elements ER(m). Therefore, the first coefficient a(m) and the second coefficient b(m) are prepared separately for the variable resistors ER1 and ER2. The individual first coefficients a(m) and second coefficients b(m) are stored in the storage unit 80. The storage unit 80 is, for example, a rewritable non-volatile memory such as a flash memory.

[0097] The temperature detection circuit 90 is a circuit having the function of accessing the memory unit 80, reading out each first coefficient a(m) and each second coefficient b(m) corresponding to the output potential Vout(m) output from each temperature sensor SENS(m), and calculating the temperature of each partial temperature detection area PA in the temperature detection area SA.

[0098] When the variable resistor ER1 is regarded as a temperature detection resistor element ER(m), the input potential Vin is provided to the input terminal Vin1, and the output potential Vout(m) is obtained from the output terminal Vout1. When the variable resistor ER2 is regarded as a temperature detection resistor element ER(m), the input potential Vin is provided to the input terminal Vin2, and the output potential Vout(m) is obtained from the output terminal Vout2. The temperature detection circuit 90 calculates a temperature (first temperature) based on the resistance value of the variable resistor ER1 and a temperature (second temperature) based on the resistance value of the variable resistor ER2 separately. The temperature detection circuit 90 may determine the temperature of the temperature detection panel PNL provided with the variable resistor (e.g., the variable resistor ER1 and the variable resistor ER2) and the display device 1 including the temperature detection panel PNL as the average of the first temperature and the second temperature, or may determine the higher of the first temperature and the second temperature. In the embodiment, the temperature detection panel PNL is regarded as the temperature of the display device 1. When there are a plurality of temperature detection panels PNL, the temperature of the display device 1 is determined to be the average of the temperatures of the plurality of temperature detection panels PNL or the temperature of the temperature detection panel PNL in which the highest temperature is detected.

[0099] The temperature of the display device 1 obtained by the temperature detection circuit 90 is output to the control unit 99. The control unit 99 includes a circuit that adjusts the reproduced color of the display panel 30 according to the temperature detected by the temperature detection unit 100. For example, the control unit 99 outputs to a DDIC 39 (Display Driver Integrated Circuits) of the display panel 30 to apply a gamma curve corresponding to the temperature to the display panel 30. The DDIC 39 controls the potential difference between the pixel electrodes P and the common electrode CE (see FIG. 2) of the display panel 30 according to the output. Details regarding the adjustment of reproduced colors by the control unit 99 will be described later with reference to FIGS. 21 to 24.

[0100] Next, a configuration example in which the variable resistor included in the temperature sensor unit SENS is provided in the first display area interior SA1, the second display area interior SA2, or the third display area interior SA3 will be described with reference to FIG.

[0101] Fig. 20 is a diagram showing a schematic shape of a temperature detection section when a temperature detection resistive element ER is arranged inside the display area SA. The panel PNL in the example shown in Fig. 20 includes a panel PNLk, a temperature sensor section SENS, a memory section 80, and a temperature detection circuit 90. The temperature sensor section SENS shown in Fig. 20 is a collection of multiple temperature sensors SENS(m) (see Fig. 19). The panel PNLk is the first panel PNL1 or the second panel PNL2.

[0102] The panel PNLk has a temperature detection area SA and a frame area GA. The temperature detection area SA includes a plurality of partial temperature detection areas PA. Each of the partial temperature detection areas PA is an area in which a plurality of temperature detection resistance elements ER of the temperature sensor unit SENS is provided. In FIG. 20, five partial temperature detection areas PA are arranged in the first direction Dx and three partial temperature detection areas PA are arranged in the second direction Dy, resulting in a total of 15 partial temperature detection areas PA, but the number of partial temperature detection areas PA is not limited to this. For example, a configuration in which four partial temperature detection areas PA are arranged in the first direction Dx and three partial temperature detection areas PA are arranged in the second direction Dy, resulting in a total of 12 partial temperature detection areas PA, may also be adopted.

[0103] The first direction Dx is a direction in a plane parallel to the panel PNLk. The second direction Dy is a direction in a plane parallel to the panel PNLk and perpendicular to the first direction Dx. The second direction Dy may not be perpendicular to the first direction Dx but may intersect with it. The third direction Dz is a direction perpendicular to the first direction Dx and the second direction Dy, and is a normal direction to the panel PNLk.

[0104] The temperature detection resistor ER is an electric resistor made of an alloy, a compound containing a metal (metal compound), or a metal. The resistor ER may be a laminate in which a plurality of materials corresponding to at least one of a metal, an alloy, and a metal compound are laminated. In the embodiment, the temperature detection resistor ER is formed of a material having translucency, such as ITO (Indium Tin Oxide). In the example shown in FIG. 20, the temperature detection resistor ER is in a form in which a plurality of L-shaped wirings whose long sides are aligned with the second direction Dy are connected in the first direction Dx. In this form, the plurality of L-shaped wirings are connected so that the short sides of two L-shaped wirings adjacent to each other in the first direction Dx are staggered in the second direction Dy, thereby forming the shape of the temperature detection resistor ER.

[0105] The frame region GA is provided with a plurality of reference resistors 71 and a storage unit 80. The temperature detection resistive elements ER provided in the partial temperature detection region PA and the reference resistors 71 provided in the frame region GA constitute a temperature sensor unit SENS.

[0106] If the number of partial temperature detection areas PA is M (in the example shown in FIG. 20, M=15), any natural number from 1 to M is substituted for m. The temperature detection circuit 90 regards each of the M resistance elements ER as a temperature detection resistance element ER(m), and derives the temperature of the temperature detection panel PNL in which the temperature detection resistance element ER is provided and the display device 1 including the temperature detection panel PNL in a manner similar to that described with reference to FIG.

[0107] Next, the relationship between the temperature of the temperature detection panel PNL and the reproduced color in the display output of the display device 1 will be described with reference to Fig. 21 to Fig. 24. First, the case where the temperature detection panel PNL is the display panel 30 will be described with reference to Fig. 21 and Fig. 22.

[0108] FIG. 21 is a graph showing the VT characteristics of the display panel 30. The VT characteristics are the relationship between the voltage applied to the liquid crystal and the degree of light transmission according to the orientation of the liquid crystal molecules contained in the liquid crystal to which the applied voltage is applied. In FIGS. 21 and 23, the degree of light transmission is shown as a normalized transmittance. In other words, the level of the normalized transmittance according to the voltage applied to the liquid crystal depends on the VT characteristics. FIG. 21 shows the cases where the temperature of the display panel 30 is -30 degrees (°C), 25 degrees (°C), and 80 degrees (°C) separately.

[0109] The display panel 30 of the embodiment is a so-called normally black transmissive liquid crystal panel. In general, in a normally black transmissive liquid crystal panel, when the normalized transmittance is increased, a control is applied to increase the voltage applied to the liquid crystal. However, as shown in FIG. 21, when the temperature of the display panel 30 is −30 degrees (° C.), the normalized transmittance is less than 1 even if the voltage applied to the liquid crystal LQ of the display panel 30 exceeds 6 V. On the other hand, when the temperature of the display panel 30 is 25 degrees (° C.), if the voltage applied to the liquid crystal LQ of the display panel 30 is 6 V, the normalized transmittance is 1. Also, when the temperature of the display panel 30 is 80 degrees (° C.), when the voltage applied to the liquid crystal LQ of the display panel 30 is between 5 V and 5.5 V, the normalized transmittance is 1. In this way, the VT characteristic of the display panel 30 changes depending on the temperature.

[0110] 22 is an xy chromaticity diagram showing the relationship between the temperature of the display panel 30 and the chromaticity of the color reproduced by the display output of the display panel 30. The lower the x chromaticity, the stronger the blueness, and the higher the x chromaticity, the stronger the redness. The lower the y chromaticity, the stronger the blueness, and the higher the y chromaticity, the stronger the greenness.

[0111] Chromaticities PC1, PC2, and PC3 in Fig. 22 are chromaticities when the voltage applied to the liquid crystal LQ is equal, but the temperatures of the display panel 30 are different. When chromaticity PC3 is obtained, the temperature of the display panel 30 is higher than when chromaticity PC1 and chromaticity PC2 are obtained. When chromaticity PC2 is obtained, the temperature of the display panel 30 is higher than when chromaticity PC1 is obtained.

[0112] The VT characteristic of the display panel 30, i.e., the level of normalized transmittance according to the applied voltage, changes with temperature, and therefore the chromaticity of the reproduced color in the display output of the display panel 30 also changes with temperature. Specifically, as shown by the relationship between chromaticity PC1, chromaticity PC2, and chromaticity PC3 in Fig. 22, the higher the temperature, the more bluish the chromaticity of the reproduced color in the display output of the display panel 30 becomes.

[0113] Next, a case where the temperature detection panel PNL is the liquid crystal panel 20 will be described with reference to FIG.

[0114] Fig. 23 is a graph showing the VT characteristics of the liquid crystal panel 20. Fig. 23 shows cases where the temperature of the liquid crystal panel 20 is -30 degrees (°C), 0 degrees (°C), 25 degrees (°C), and 60 degrees (°C).

[0115] The liquid crystal panel 20 of the embodiment is a so-called normally white transmissive liquid crystal panel. In general, in a normally white transmissive liquid crystal panel, when the normalized transmittance is to be lowered, a control is applied to increase the voltage applied to the liquid crystal. As shown in FIG. 21, when the temperature of the liquid crystal panel 20 is −30 degrees (° C.), the normalized transmittance is approximately 1 when the voltage applied to the liquid crystal LM of the liquid crystal panel 20 is 2.2 V or less. On the other hand, when the temperature of the liquid crystal panel 20 is 0 degrees (° C.), the normalized transmittance becomes less than 1 when the voltage applied to the liquid crystal LM of the liquid crystal panel 20 exceeds 2 V. In addition, when the temperature of the display panel 30 is 25 degrees (° C.), the normalized transmittance becomes less than 1 when the voltage applied to the liquid crystal LM of the display panel 30 exceeds 2 V, and the degree of decrease in the normalized transmittance according to the increase in voltage when an applied voltage exceeding 2 V is applied is more remarkable than when the temperature of the liquid crystal panel 20 is 0 degrees (° C.). Furthermore, when the temperature of the liquid crystal panel 20 is 80 degrees (° C.), the normalized transmittance becomes less than 1 when the voltage applied to the liquid crystal LM of the liquid crystal panel 20 becomes equal to or higher than 1.9 V. In this way, the VT characteristic of the liquid crystal panel 20 changes with temperature.

[0116] Next, the relationship between the temperature of the display device 1 and the reproduced colors in the display output will be described with reference to FIG.

[0117] FIG. 24 is an xy chromaticity diagram showing the relationship between the temperature of the display device 1 and the chromaticity of the color reproduced by the display output of the display device 1. In FIG. 24, visual control OFF refers to the first state. Moreover, visual control ON refers to the second state. Chromaticity OFF1, chromaticity OFF2, and chromaticity OFF3 in FIG. 24 are chromaticities in the case where the conditions related to the voltages applied to the liquid crystal LQ and the liquid crystal LM are the same, but the temperatures of the display device 1, which is the first state, are different from each other. When chromaticity OFF3 is obtained, the temperature of the display device 1 is higher than when chromaticity OFF1 and chromaticity OFF2 are obtained. When chromaticity OFF2 is obtained, the temperature of the display device 1 is higher than when chromaticity OFF1 is obtained. Chromaticity ON1, chromaticity ON2, and chromaticity ON3 are chromaticities in the case where the conditions related to the voltages applied to the liquid crystal LQ and the liquid crystal LM are the same, but the temperatures of the display device 1, which is the second state, are different from each other. When chromaticity ON3 is obtained, the temperature of the display device 1 is higher than when chromaticity ON1 and chromaticity ON2 are obtained. When chromaticity ON2 is obtained, the temperature of the display device 1 is higher than when chromaticity ON1 is obtained. Note that when chromaticity OFF1 is obtained, the temperature of the display device 1 is the same as when chromaticity ON1 is obtained. Also, when chromaticity OFF2 is obtained, the temperature of the display device 1 is the same as when chromaticity ON2 is obtained. Also, when chromaticity OFF3 is obtained, the temperature of the display device 1 is the same as when chromaticity ON3 is obtained.

[0118] The display output of the display device 1 is light from the light source 60 that has passed through the liquid crystal panel 20 and the display panel 30. Therefore, the display output of the display device 1 is affected by both the relationship between the temperature and the VT characteristics of the liquid crystal panel 20 and the relationship between the temperature and the VT characteristics of the display panel 30. As described with reference to Figures 1 and 2, the liquid crystal panel 20 and the display panel 30, which essentially constitute an integrated device as the display device 1, are placed in substantially the same external temperature environment, and therefore the temperature of the liquid crystal panel 20 and the temperature of the display panel 30 are substantially the same.

[0119] 21 and 22, when viewed only from the display panel 30, the chromaticity of the reproduced color tends to become bluish as the temperature of the display panel 30 increases. On the other hand, as described with reference to Fig. 23, the liquid crystal panel 20 tends to show a more pronounced responsiveness to the decrease in the normalized reduction rate in response to an increase in the voltage applied to the liquid crystal LM as the temperature increases. The display output of the display device 1 reflects these tendencies of both the display panel 30 and the liquid crystal panel 20.

[0120] Specifically, as shown in Fig. 24, when the visual control is OFF, that is, in the first state, as shown by the positional relationship between chromaticity OFF1, chromaticity OFF2, and chromaticity OFF3, redness tends to weaken and greenness tends to strengthen up to a predetermined temperature (temperature at which chromaticity OFF2 is obtained), but when the low temperatures are exceeded, redness tends to strengthen and greenness tends to weaken. Also, when the visual control is ON, that is, in the second state, as shown by the positional relationship between chromaticity ON1, chromaticity ON2, and chromaticity ON3, redness and greenness tend to strengthen up to a predetermined temperature (temperature at which chromaticity ON2 is obtained), but when the low temperatures are exceeded, redness and greenness tend to weaken.

[0121] 21 to 24, the chromaticity of reproduced colors in the display output of the display device 1 is affected by the temperature of the display device 1. Therefore, by adjusting the reproduced colors of the display panel 30 in accordance with the temperature, it is possible to make the effect of temperature on the chromaticity of reproduced colors substantially invisible.

[0122] Specifically, in consideration of the relationship between the temperature and chromaticity of the display device 1 described with reference to Fig. 24, gamma curves for different temperatures of the display device 1 are prepared in advance, and a gamma curve corresponding to the temperature of the temperature detection panel PNL detected by the temperature detection unit is applied to the display panel 30, so that the temperature of the reproduced color can be substantially uniform regardless of the temperature. Based on the description with reference to Fig. 24, in the first state, a gamma curve is applied in which the chromaticity at the temperature at which the chromaticity OFF2 is obtained is used as a reference, and a gamma curve is applied in which the redness is strengthened and the greenness is weakened when the temperature is low, and a gamma curve is applied in which the redness is weakened and the greenness is strengthened when the temperature is high. In the second state, a gamma curve is applied in which the chromaticity at the temperature at which the chromaticity ON2 is obtained is used as a reference, and a gamma curve is applied in which the redness and greenness are weakened when the temperature is low, and a gamma curve is applied in which the redness and greenness are strengthened when the temperature is high.

[0123] Furthermore, in order to eliminate the difference in chromaticity between the first state and the second state described with reference to Figure 24, a gamma curve for the first state and a gamma curve for the second state are prepared for each temperature, and a gamma curve according to the temperature of the temperature detection panel PNL detected by the temperature detection unit and the operating state of the display device 1 (first state or second state) is applied to the display panel 30, thereby making it possible to roughly unify the temperature of the reproduced colors regardless of the temperature or the operating state of the display device 1.

[0124] As described above, according to the embodiment, the display device 1 includes a display panel 30 having a display area AA that outputs an image, a light source 60 that irradiates light from one side of the display panel 30, a liquid crystal panel 20 that is interposed between the display panel 30 and the light source 60 so as to be able to change the degree of light transmission between the display panel 30 and the light source 60, a temperature detection unit 100 that detects the temperature of at least one of the display panel 30 and the liquid crystal panel 20, and a control unit 99 that adjusts the color reproduced by the display panel 30 in accordance with the temperature detected by the temperature detection unit 100.

[0125] This allows the reproduced color by the display panel 30 to correspond to the temperature detected by the temperature detection unit 100. In other words, by adjusting the reproduced color so that substantially the same reproduced color can be obtained regardless of the temperature, it is possible to suppress changes in the display output due to changes in temperature.

[0126] Furthermore, by the control unit 99 applying a gamma curve according to the temperature of the display device 1 to the display panel 30, it is possible to more reliably adjust the reproduced colors so that substantially the same reproduced colors can be obtained regardless of the temperature. Therefore, it is possible to more reliably suppress changes in the display output due to changes in temperature.

[0127] Furthermore, the temperature detection unit 100 has a variable resistor (for example, the temperature detection resistive element ER shown in FIG. 20, the variable resistor ER1 and the variable resistor ER2 shown in FIG. 19, etc.) that exhibits an electrical resistance value according to the temperature, and detects the temperature based on the electrical resistance value of the variable resistor, thereby enabling temperature detection with a simple mechanism.

[0128] Furthermore, the variable resistors ER1 and ER2 (see FIG. 19), which function as variable resistors, are provided in the frame area GA (see FIG. 15 and FIG. 16) that frames the display area AA, which is provided in the panel to be able to transmit light from the light source 60, so that there is no need to consider the direct effect that the configuration functioning as the variable resistor has on the display output, and the degree of freedom in selecting the material of the variable resistor is further improved. Therefore, it becomes easier to use a material for the variable resistor that is more suitable for calculating temperature based on the correspondence between temperature and electrical resistance value and has higher responsiveness to temperature. This makes it easier to improve the accuracy of temperature detection.

[0129] Furthermore, a temperature-detecting resistive element ER (see FIG. 20) functioning as a variable resistor has light-transmitting properties and is provided in the display area AA, thereby making it possible to detect the temperature of the display area AA, which is the part of the display device 1 that contributes most to the display output. This makes it possible to adjust the reproduced color according to the temperature of the display area AA, thereby more reliably suppressing changes in the display output due to changes in temperature.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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]

[0135] 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 99 Control section 100 Temperature detection unit AA display area ER(m) Temperature sensing resistor element GA Frame Area

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 temperature detection unit that detects a temperature of at least one of the display panel and the liquid crystal panel; a control unit that adjusts the color reproduced by the display panel in response to the temperature detected by the temperature detection unit. Display device.

2. The control unit applies a gamma curve according to temperature to the display panel. The display device according to claim 1 .

3. the temperature detection unit has a variable resistor that exhibits an electrical resistance value according to temperature, and detects temperature based on the electrical resistance value of the variable resistor. The display device according to claim 1 .

4. the variable resistor is provided in a frame region of the panel that borders a display region that is provided to be capable of transmitting light from the light source; The display device according to claim 3 .

5. the variable resistor has a light-transmitting property and is provided in a display area of ​​the panel that is provided to be capable of transmitting light from the light source; The display device according to claim 3 .

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