Display device

Abstract

Provided is a display device capable of ensuring the confidentiality of a specific image and improving the visually recognized image quality. A display device (10) is provided with: a display panel (12); a polarization module (11) which is disposed so as to overlap the display panel and which is capable of actively switching a polarization state between a first polarization state and a second polarization state; a backlight (13) disposed so as to overlap the display panel; and a controller (20). The controller is configured to generate second image data from the first image data, display a first image based on the first image data and a second image based on the second image data on the display panel in a time division manner, and switch a polarization state of the polarization module in synchronization with timing of the time division so that the polarization state is a first polarization state when the first image is displayed and the polarization state is a second polarization state when the second image is displayed. When the first image is displayed, the second image is in a second polarization state, and the backlight is controlled so as to be turned off during a predetermined period from the start of a display period in which the first or second image is displayed on the display panel and then turned on.

Description

Technical Field

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

[0002] Sometimes, it is desirable to display secret information, private information, etc. only under certain conditions. For example, Japanese Patent Application Laid-Open No. 2001-255844 (hereinafter referred to as Patent Document 1) discloses a system in which a user who visually recognizes a display using an active pair of glasses with shutter lenses can see private data, while an unauthorized observer who does not have active glasses can only see private data covered by masking data. Prior art literature Patent Literature

[0003] Patent Document 1: Japanese Patent Application Publication No. 2001-255844 Summary of the invention

[0004] Sometimes, it is desired to visually recognize a confidential image with good image quality. Therefore, a display device that can ensure the confidentiality of a specific image and improve the quality of the image to be visually recognized is desired.

[0005] According to a certain embodiment, a display device includes: a display panel; a polarization module, which is overlapped with the display panel and can actively switch the polarization state between a first polarization state and a second polarization state; a backlight source, which is overlapped with the display panel; and a controller. The controller is configured to: generate second image data based on first image data, display a first image based on the first image data and a second image based on the second image data on the display panel in a time-division manner, switch the polarization state of the polarization module synchronously with the timing of the time division so that the first polarization state is used when the first image is displayed and the second polarization state is used when the second image is displayed, and control the backlight source so that it is extinguished within a specified period from the beginning of the display period in which the first image or the second image is displayed on the display panel, and then illuminated.

[0006] Further details will be described as the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic configuration diagram of a display system according to the first embodiment. Figure 2 This is a schematic cross-sectional view of a display device included in the display system. Figure 3 This is a schematic plan view of the display device as viewed from the observation surface side. Figure 4 It is a schematic plan view showing an example of the arrangement (layout) of the first spacer and the second spacer included in the polarization module included in the display device. Figure 5 FIG. 1 is a diagram showing an example of a first image and a second image. Figure 6 It is a diagram showing an example of a lookup table (LUT). Figure 7 This is a schematic diagram showing a partial configuration of a display system. Figure 8 This is a diagram for explaining the brightness visually recognized when an observer does not wear polarized glasses. Fig. 9 This is a diagram for explaining the brightness visually recognized when an observer does not wear polarized glasses. Fig.10 This is a schematic diagram showing the relationship between the display of the display panel, the polarization state of the polarization module, and the lighting state of the backlight in the display system according to the first embodiment. Fig.11 This is a flowchart showing an example of a method for controlling a display device in a display system. Fig.12 This is a flowchart showing an example of a method for controlling a display device in a display system. Fig.13 This is a flowchart showing an example of a method for controlling a display device in a display system. Fig.14 It is a schematic diagram showing an example of the display of the display panel, the polarization state of the polarization module, and the image perceived by the observer. Fig.15 It is a schematic diagram showing an example of the display of the display panel, the polarization state of the polarization module, and the image perceived by the observer. Fig.16 This is a diagram for explaining the brightness visually recognized by an observer wearing polarized glasses. Fig.17 This is a diagram for explaining the brightness visually recognized by an observer wearing polarized glasses. Fig.18 It is a schematic diagram of the configuration of a display system according to the second embodiment. Fig.19 This is a diagram for explaining an example of a non-lighting period and a lighting period in the display system according to the second embodiment. Fig. 20 This is a diagram for explaining an example of a method of generating second image data from first image data in the display system according to the second embodiment. Fig.21 is a diagram showing another example of the LUT. Fig. 22 It is used to illustrate Fig.21 A diagram of the relationship of data set A specified in the LUT. Fig.23 This is a schematic diagram showing an example of display of a display panel, a polarization state of a polarization module, and an image perceived by an observer in a display system according to the second embodiment. Fig.24 This is a schematic diagram for explaining the relationship between the display of the display panel, the polarization state of the polarization module, and the lighting state of the backlight in the display system according to the modification. DETAILED DESCRIPTION

[0008] <1. Overview of Display Device> (1) A display device according to an embodiment includes: a display panel; a polarization module, which is overlapped with the display panel and can actively switch the polarization state between a first polarization state and a second polarization state; a backlight, which is overlapped with the display panel; and a controller. The controller is configured to: generate second image data based on first image data, display a first image based on the first image data and a second image based on the second image data on the display panel in a time-division manner, switch the polarization state of the polarization module in synchronization with the timing of the time division so that the first polarization state is used when the first image is displayed and the second polarization state is used when the second image is displayed, and control the backlight so that the backlight is turned off for a predetermined period from the start of a display period in which the first image or the second image is displayed on the display panel, and then turns on.

[0009] The observer uses polarized glasses, which transmit the image emitted from the polarization module in the first polarization state as the image displayed on the display panel, but do not transmit the image emitted in the second polarization state. When the observer wears the polarized glasses, during the period when the backlight source is lit, only the first image of the first image and the second image switched and displayed in a time-division manner on the display panel is visually recognized. When the observer does not wear the polarized glasses, during the period when the backlight source is lit, both the first image and the second image switched and displayed in a time-division manner on the display panel are visually recognized. If the switching of the display of the first image and the second image is performed at a speed that is not only perceived by the first image and does not feel flicker when the observer does not wear the polarized glasses, then when the observer does not wear the polarized glasses, the composite image of the first image and the second image is perceived. Thus, the first image can be perceived only when the polarized glasses are worn or only by the user wearing the polarized glasses. At this time, it is not necessary to change the polarization state of the polarized glasses synchronously with the display on the display panel. Therefore, it is not necessary to control the polarized glasses through wireless communication or the like. In addition, the polarized glasses do not require a control mechanism or a power supply. Therefore, the display device according to the present embodiment can ensure the confidentiality of a specific image (first image) without impairing the usability.

[0010] Furthermore, in the display device according to the embodiment, the backlight source is turned off during a predetermined period (non-lighting period) from the start of the display period in which the first image or the second image is displayed on the display panel, and then the backlight source is turned on (lighting period). By setting the non-lighting period during a period when the brightness is unstable, such as just after the first image or the second image is written on the display panel, and setting the lighting period during a period when the brightness is stable, the image is irradiated from the display panel with stable brightness. Thus, the quality of the first image visually recognized by the observer when not wearing polarized glasses can be improved.

[0011] (2) In the display device described in (1), preferably, switching the polarization state of the polarization module includes: dividing the polarization module into a plurality of segments along the scanning direction, and switching the polarization states of the plurality of segments with a time difference in the order along the scanning direction. Thus, at each position in the scanning direction of the display panel, the polarization module is in the first polarization state while the first image is irradiated with a stable brightness. Therefore, compared with the case where the polarization state of the entire polarization module is uniformly switched at the beginning of the display of each image, the difference (unevenness) in the brightness of the first image visually recognized by the observer when wearing the above-mentioned polarized glasses can be suppressed. In addition, the brightness of the display panel is stable. As a result, the display quality when the observer wears the polarized glasses is improved.

[0012] (3) In the display device described in (2), preferably, controlling the backlight source includes lighting the backlight source during a period when the polarization states of the plurality of segments of the corresponding polarization module are all in the first polarization state or in the second polarization state. Thus, the quality of the first image visually recognized by the observer when not wearing polarized glasses can be improved.

[0013] (4) In the display device described in (2), preferably, controlling the backlight source includes: lighting the backlight source during a period when the polarization states of the plurality of segments of the corresponding polarization module are all in the first polarization state when the first image is displayed, or during a period when the polarization states of the plurality of segments of the corresponding polarization module are all in the second polarization state when the second image is displayed. In this way, the quality of the first image visually recognized by the observer when not wearing polarized glasses can be improved.

[0014] (5) In the display device described in (4), preferably, the light-emitting surface of the backlight source is divided into a plurality of segments, and controlling the backlight source includes: in order along the scanning direction of the display panel, the plurality of segments are turned off for a predetermined period of time from the start of writing the first image or the second image for the area in the display panel corresponding to each of the plurality of segments, and then turned on again. Thus, compared with the case where the entire back panel is turned off and on uniformly, the first image is illuminated at a stable brightness at each position in the scanning direction of the display panel.

[0015] (6) In the display device described in (1) to (5), preferably, controlling the backlight includes: making the amount of light irradiated from the backlight different between the display period for displaying the first image and the display period for displaying the second image. Thus, the amount of light irradiated from the backlight can be made different between the first display period and the second display period according to characteristics such as response conditions of the display panel and the polarization module. As a result, the brightness of the image irradiated from the display panel is more stable.

[0016] (7) In the display device described in (6), preferably, making the amount of light irradiated from the backlight different includes: making the length of the period during which the backlight is turned on different between the display period during which the first image is displayed and the display period during which the second image is displayed. Thus, the amount of light irradiated from the backlight can be made different between the first display period and the second display period.

[0017] (8) In the display device described in (1) to (7), preferably, the first polarization state enables the observer to visually recognize the first image through polarized glasses worn by the observer, and the second polarization state enables the observer to visually not recognize the second image through the polarized glasses. Thus, by using polarized glasses, as described above, the confidentiality of the first image can be easily ensured.

[0018] (9) In the display device described in (1) to (8), preferably, generating the second image data includes: converting the grayscale of the image data into a grayscale having a predetermined corresponding relationship, so that the composite image of the first image and the second image becomes an image of a grayscale corresponding to the predetermined relationship.

[0019] (10) In the display device described in (1) to (9), preferably, generating the second image data includes: dividing the image data into a plurality of regions, changing the grayscale to a predetermined corresponding relationship selected for each region, and the corresponding relationships selected for the plurality of regions include at least two corresponding relationships. Thus, the composite image of the first image and the second image becomes an image of grayscales corresponding to the predetermined relationships of the plurality of regions.

[0020] <2. Example of Display Device>

[0021] [First embodiment] Figure 1 1 is a schematic diagram of a display system 100 according to the first embodiment. The display system 100 includes a display device 10 and a controller 20 for controlling display on the display device 10. The display device 10 is mounted on, for example, a smartphone, a tablet terminal, a smart watch, an in-vehicle information display, a personal computer, a monitor for a personal computer, and a television (TV).

[0022] Figure 21 is a schematic cross-sectional view of a display device 10. The display device 10 includes a display 30 and a polarization module 11 arranged to overlap with the display 30. Figure 2 In FIG. 1 , the polarization module 11 is shown to be spaced apart from the display 30, but the polarization module 11 and the display 30 may not be spaced apart or may overlap with each other at a very small distance. The display 30 includes a display panel 12 and a backlight source 13 arranged to overlap with the back surface (lower surface) of the display panel 12. Figure 2 In FIG. 1 , the backlight source 13 is shown to be spaced apart from the display panel 12, but the backlight source 13 and the display panel 12 may not be spaced apart, or may overlap with a very small space. The polarization module 11 is disposed on the front surface (upper surface) of the display panel 12. The display device 10 is observed by the observer A from the front surface side of the display panel 12. Therefore, the front surface of the display panel 12 is also an observation surface.

[0023] Figure 3 This is a schematic top view of the display device 10 when viewed from the observation surface side. As an example, the display device 10 has a display area 1100 and a frame area 1200 arranged in a frame shape at the outer edge of the display area 1100. The display area 1100 is an area where an arbitrary image or the like is displayed. That is, it is an area visually recognized from the observation surface side of the display device 10 when the backlight source 13 is turned on. The frame area 1200 is opaque. The display device 10 may not have the frame area 1200.

[0024] The display panel 12 has a plurality of pixels. Preferably, the plurality of pixels are arranged in a matrix form on the display panel 12. The structure of the display panel 12 is not particularly limited. The display panel 12 may be, for example, a structure in which a liquid crystal layer is clamped between a pair of substrates. In detail, the display panel 12 may also be displayed by clamping a liquid crystal layer between a pair of substrates having pixel electrodes and a common electrode formed on one substrate, applying a voltage between the pixel electrodes and the common electrode, and applying a lateral electric field (including a fringe electric field) to the liquid crystal layer. As another example, the display panel 12 may also be displayed by clamping a liquid crystal layer between a pair of substrates having pixel electrodes formed on one substrate and a common electrode formed on the other substrate, applying a voltage between the pixel electrodes and the common electrode, and applying a longitudinal electric field to the liquid crystal layer. As a lateral electric field mode, FFS mode, IPS mode, etc. may be listed, and as a longitudinal electric field mode, VA (Vertical Alignment) mode, TN (Twisted Nematic) mode, etc. may be listed.

[0025] The liquid crystal mode of the display panel 12 is not particularly limited. The liquid crystal mode of the display panel 12 can be, for example, black display by aligning the liquid crystal molecules in the liquid crystal layer 260 perpendicular to the substrate surface, or black display by aligning the liquid crystal molecules in the liquid crystal layer 260 in a direction parallel to or not perpendicular to or not parallel to the substrate surface. In addition, as a driving mode of the display panel 12, in addition to the TFT mode (active matrix mode), a simple matrix mode (passive matrix mode), a plasma addressing mode, etc. may also be used.

[0026] As an example, the display panel 12 has a structure in which a liquid crystal layer 260 is sandwiched between a pair of substrates 211 and 212, and the liquid crystal layer 260 is sandwiched by insulating films 231 and 232. Pixel electrodes and common electrodes not shown are provided on one substrate (substrate 211). A black matrix layer (BM layer) 250 and color filter layers 240 (blue filter layer 240B, red filter layer 240R, and green filter layer 240G) regularly arranged between the BM layers are formed on the substrate 211. The display panel 12 preferably has a BM layer 250, and the BM layer 250 is configured in a lattice shape when viewed from above.

[0027] The display panel 12 is connected to the display panel driving unit 16, and displays are realized by the display panel driving unit 16. The display panel 12 switches the main image (first image) and the sub-image (second image) described later in a time-division manner under the control of the display panel driving unit 16 and displays them sequentially.

[0028] The backlight 13 includes a plurality of light sources, for example, and is a scanning backlight capable of controlling the plurality of light sources individually. For example, the light source is an LED (Light Emitting Diode).

[0029] The backlight source 13 is connected to a backlight source (BL) driving unit 17, and the turning on and off of a plurality of light sources not shown is independently controlled by the BL driving unit 17. As described later, when the display panel driving unit 16 switches a first image and a second image to be described later on the display panel 12 in a time-division manner and displays them sequentially, the BL driving unit 17 controls the backlight source 13 in synchronization with the switching timing of the display.

[0030] As an example, the polarization module 11 is a panel composed of an active retarder. The polarization module 11 is switched to a plurality of polarization states by the AR (Active Retarder) panel driver 15. The polarization module 11 is switched to a first polarization state and a second polarization state in synchronization with the switching of the main image (first image) and the sub-image (second image) in the display panel 12 according to the control of the AR panel driver 15. As an example, when the first image is displayed on the display panel 12, the polarization module 11 becomes the first polarization state, and when the second image is displayed on the display panel 12, the polarization module 11 becomes the second polarization state.

[0031] Observer A uses detachable polarized glasses 200 to observe the display of the display area 1100. In addition, the polarized glasses 200 do not have a shutter function. When observer A wears the polarized glasses 200, the display displayed on the display panel 12 and illuminated from behind by the lit backlight 13 is given a polarization state by the polarization module 11, and reaches the eyes of observer A through the polarized glasses 200. When observer A does not wear the polarized glasses 200, the display displayed on the display panel 12 and illuminated from behind by the lit backlight 13 is given a polarization state by the polarization module 11, and does not reach the eyes of observer A through the polarized glasses 200. In the following description, it is expressed as when an image is displayed on the display panel 12 and illuminated from behind by the lit backlight 13, an image is displayed or illuminated from the display panel 12. The display illuminated from the display panel 12 entering the field of view of observer A is called "visual recognition", and the perception and grasp of the display entering the field of view is called "perception".

[0032] Polarized glasses 200 have polarized films attached to two lenses. The polarized films are preferably circularly polarized films. The polarized films are not limited to circularly polarized films, and may be other types of polarized films.

[0033] The polarization glasses 200 transmit the image emitted from the display panel 12 in the first polarization state of the polarization module 11, and do not transmit the image emitted from the display panel 12 in the second polarization state. In other words, the first polarization state in the polarization module 11 is a polarization state in which the first image emitted from the display panel 12 is transmitted through the polarization glasses 200, and the second polarization state is a polarization state in which the second image emitted from the display panel 12 is not transmitted through the polarization glasses 200.

[0034] Thus, when the observer A is not wearing the polarized glasses 200, he / she visually recognizes both the first image and the second image switched and irradiated from the display panel 12 in a time-division manner. When the observer A is wearing the polarized glasses 200, he / she visually recognizes only the first image of the first image and the second image switched and irradiated from the display panel 12 in a time-division manner. In the display system 100, it is not necessary to change the polarization state of the polarized glasses 200 synchronously with the display on the display panel 12. Therefore, it is not necessary to control the polarized glasses 200 by wireless communication or the like. In addition, the polarized glasses 200 do not require a control mechanism or a power supply.

[0035] The polarization module 11 includes an optical stack 110 and a phase difference plate 120. The optical stack 110 includes a pair of substrates 111, 112, a pair of electrodes 121, 122, a liquid crystal layer 160, and columnar spacers 151, 152. More specifically, from the observation side, there are a first substrate 111, a first electrode 121, a liquid crystal layer 160, a second electrode 122, and a second substrate 112. A light shielding layer 170 for limited light shielding of the columnar spacers 151, 152 is provided between the first substrate 111 and the first electrode 121, and a flattening film 180 is provided between the light shielding layer 170 and the first electrode 121. In addition, between each of the electrodes 121, 122 and the liquid crystal layer 160, insulating films 131, 132, and alignment films 41, 142 are sequentially arranged from the electrode side.

[0036] The second spacer 152 is disposed to control the thickness of the liquid crystal layer 160. The first spacer 151 is disposed in a floating island shape. Thus, the polarization module 11 can be provided with resistance to surface pressure.

[0037] The first spacer 151 is arranged in a floating island shape, which means that the first spacer 151 is arranged in a floating island shape in the liquid crystal layer 160. Specifically, it means that the liquid crystal layer 160 exists between the first spacer 151 and the first substrate 111 or the second substrate 112 in cross-section. That is, the height of the first spacer 151 is less than the thickness of the liquid crystal layer 160. On the other hand, the height of the second spacer 152 is equal to the thickness of the liquid crystal layer 160.

[0038] The height of the first spacer 151 is smaller than the thickness of the liquid crystal layer 160. That is, when the thickness of the liquid crystal layer 160 is set to 100%, the height of the first spacer 151 may be a value smaller than 100%, for example, 5 to 95%.

[0039] The first spacer 151 and the second spacer 152 are formed of, for example, a light-transmitting resin material. The first spacer 151 and the second spacer 152 can be formed by forming a plurality of columnar spacers of different heights on one substrate (e.g., the first substrate 111). Specifically, for example, after columnar spacers of different heights are formed on the first substrate 111, the second substrate 112 is attached with a liquid crystal material sandwiched therebetween, and the columnar spacer having a height lower than the thickness of the liquid crystal layer 160 formed by the liquid crystal material becomes the first spacer 15, and the other columnar spacers become the second spacer 152.

[0040] The optical laminate 110 has a light shielding portion (also referred to as a light shielding layer) 170 as an example of a light shielding unit for limitedly shielding the first spacer 151 and the second spacer 152. The light shielding portion 170 is arranged at a position overlapping with the columnar spacer. By having such a light shielding unit, the degradation of display performance caused by the phase difference deviation around the columnar spacer can be fully suppressed.

[0041] The light shielding portion 170 is arranged at a position overlapping with the columnar spacer, which means that 80% to 100% of the area of ​​the columnar spacer overlaps with the light shielding layer in a plan view. Preferably, 85% to 100%, more preferably 90% to 100% of the area of ​​the columnar spacer overlaps with the light shielding layer.

[0042] The light shielding portion 170 is formed of a light shielding material. Examples of the light shielding material include a metal black matrix (also referred to as a metal BM) made of a metal, a resin black matrix (also referred to as a resin BM) made of a resin material, and the like. Examples of the metal BM include a metal film containing aluminum, molybdenum, chromium, titanium, or an alloy thereof. Examples of the resin BM include a black resist, among which a black photosensitive resin is preferred. Specifically, for example, a black photosensitive acrylic resin can be cited. The light shielding portion 170 can be a single-layer film or a multi-layer film.

[0043] Preferably, the light transmittance of the light shielding portion 170 is, for example, 0 to 1%. The thickness of the light shielding portion 170 is not particularly limited. The thickness of the light shielding portion 170 is, for example, 10 nm (≥10 nm) or more and 2 μm or less. The thickness of the light shielding portion 170 is more preferably 50 nm or more and 1.5 μm or less.

[0044] Figure 4It is a schematic top view showing an example of the configuration (layout) of the first spacer 151 and the second spacer 152. The units of numbers in the figure are μm. The left-right direction in the figure is parallel to the long side direction of the active area of ​​the polarization module 11, that is, the area corresponding to the display area 1100 of the display device 10. The length of the long side of the display area 1100 is set to 59.6736 cm, and the length of the pitch B parallel to the long side A of the display area 1100 in the pixel pitch of the display panel 12 is set to 77.7 μm. The unit composed of a 932.4 μm×932.4 μm angle when observing the liquid crystal layer 160 from a top view is set as a basic unit (also called a repeating unit) U, and the polarization module 11 is constructed so that the basic unit U is repeatedly configured over the entire area of ​​the liquid crystal layer 160. Figure 4 In the figure, a dotted line is used to represent a basic unit U. In the basic unit U, the diameter Two second spacers 152 of about 15.3 μm in diameter and 1.6 μm in height are arranged, and 44 first spacers 151 of about 15 μm in short axis, 40 μm in long axis, 1.3 μm in height and quarter arc shape are arranged.

[0045] In order to obtain the unit U, the interval (gap) between the first spacer 151 and other first spacers 151 adjacent thereto in the horizontal direction is first set to 37.7 μm, and the interval (gap) between the first spacer 151 and other first spacers 151 adjacent thereto in the vertical direction is first set to 217.6 μm, and a plurality of first spacers 151 are regularly arranged. Then, the third, fourth, and fifth first spacers 151 (a total of three) are removed from the left of the second row from the bottom, and one second spacer 152 (second spacer 152A) is arranged at the center of the removed area. The interval (gap) between the first spacers 151a and 151b on the left and right sides of the removed first spacers 151 (three) and the second spacer 152A arranged this time is 127.75 μm. Figure 4 The X diagram on the right side of shows that the second spacer 152A disposed here and the adjacent first spacers 151a and 151b are disposed so that the center positions in the vertical direction thereof coincide with each other.

[0046] Furthermore, the third first spacer 151 (1 piece) from the right in the fourth row from the bottom is also removed, and a second spacer 152 (second spacer 152B) is arranged at the center of the removed area. The interval (gap) between the first spacers 151c and 151d on the left and right sides of the removed first spacer 151 (1 piece) and the second spacer 152B arranged this time is 50.05 μm.

[0047] A planarization film (also referred to as a planarization layer) 180 for planarization is provided between the light shielding layer 170 and the first electrode 121. The planarization film 180 is preferably an organic insulating film, for example. As the organic insulating film, for example, an organic film with a small relative dielectric constant such as a photosensitive resin (relative dielectric constant ε=2 to 5), and a laminated film thereof can be cited. Specifically, for example, organic films such as acrylic resins, polyimide resins, and novolac resins, and their laminates can be cited. The thickness of the planarization film 180 is not particularly limited, for example, it is greater than 10 nm and less than 5 μm. The thickness of the planarization film 180 is more preferably greater than 30 nm and less than 3 μm.

[0048] The first substrate 111 and the second substrate 112 are preferably transparent substrates. The transparent substrate may be any substrate that is transparent to visible light, for example, a glass substrate, a plastic substrate, etc.

[0049] The first electrode 121 and the second electrode 122 are preferably transparent electrodes, which may be formed of transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO), or alloys thereof.

[0050] The first electrode 121 and the second electrode 122 are electrodes arranged in a planar shape on the entire surface of each substrate, that is, so-called full-surface electrodes, but may also be patterned electrodes.

[0051] As an example, the polarization module 11 is driven in ECB mode. ECB mode refers to a mode in which the birefringence of the liquid crystal layer 160 is controlled by applying a voltage, and is divided into a horizontal orientation type, a vertical orientation type (VA), and a HAN type according to the different initial orientation states of the liquid crystal molecules. In these modes, a longitudinal voltage is applied to the liquid crystal layer. In addition, the FFS (Fringe Field Switching) mode and the IPS (In-Plane Switching) mode in which a transverse voltage is applied can also be referred to as a type of ECB mode in the sense of controlling the birefringence of the liquid crystal layer by applying a voltage. In the polarization module 11 involved in the embodiment, a positive liquid crystal is used, and a longitudinal electric field type ECB mode in which the initial orientation of the liquid crystal molecules is in a horizontal orientation state is adopted.

[0052] The liquid crystal layer 160 is composed of a liquid crystal material including liquid crystal molecules 1601. By applying a voltage to the liquid crystal layer 160, the orientation state of the liquid crystal molecules 1601 changes according to the applied voltage, and the amount of light transmission can be controlled. In addition, the state in which the applied voltage to the liquid crystal layer 160 is less than the threshold value is referred to as a no-voltage-applied state.

[0053] It is preferable that the liquid crystal molecule 1601 has a positive value of dielectric anisotropy (Δε) defined by the following formula. Δε=(dielectric constant in the long axis direction)-(dielectric constant in the short axis direction)

[0054] For the liquid crystal molecules 1601, the dielectric anisotropy (Δε) defined by the following formula may also have a negative value. In the polarization module 11 involved in the embodiment, liquid crystal molecules having a positive dielectric anisotropy (Δε) are used. In addition, liquid crystal molecules having positive dielectric anisotropy are also called positive liquid crystals, and liquid crystal molecules having negative dielectric anisotropy are also called negative liquid crystals. The long axis direction of the liquid crystal molecules is the direction of the slow axis.

[0055] The liquid crystal molecules 1601 also preferably satisfy the following formula (1). K11≥γ1 / {(Δε)2×1.3×1011} Formula (1) (Wherein, K11 represents the splay elastic constant (pN) of the liquid crystal molecule 1601. γ1 represents the rotational viscosity coefficient (mPa·second) of the liquid crystal material. Δε represents the dielectric constant anisotropy of the liquid crystal molecule 1601.)

[0056] That is, it is preferable to select liquid crystal molecules having a dielectric anisotropy Δε satisfying the relationship of equation (1) as the liquid crystal molecules 1601. This can shorten the response time from voltage on to off, and obtain a polarization module 11 capable of following faster image switching.

[0057] The dielectric anisotropy Δε of the liquid crystal molecule 1601 may be within the range satisfying the above formula (1), but is preferably greater than 0.1 from the viewpoint of further achieving high-speed response. More preferably, the dielectric anisotropy Δε is greater than 0.11. In addition, from the viewpoint of considering the actual production unit thickness control, the dielectric anisotropy Δε is preferably less than 0.22. More preferably, the dielectric anisotropy Δε is less than 0.2.

[0058] From the viewpoint of further achieving high-speed response, the flexure elastic constant K11 of the liquid crystal molecule 1601 is preferably greater than 5 pN. More preferably, the flexure elastic constant K11 is greater than 10 pN. In addition, from the same viewpoint, the flexure elastic constant K11 is preferably less than 30 pN. More preferably, the flexure elastic constant K11 is less than 20 pN. Most preferably, the flexure elastic constant K11 ranges from 10 to 20 pN.

[0059] From the viewpoint of further achieving high-speed response, the rotational viscosity coefficient γ1 of the liquid crystal material constituting the liquid crystal layer 160 is preferably 100 mPa·second (mPa·s) or less. More preferably, the rotational viscosity coefficient γ1 is 60 mPa·second or less. In addition, from the same viewpoint, the rotational viscosity coefficient γ1 is preferably 20 mPa·second or more. More preferably, the rotational viscosity coefficient γ1 is 30 mPa·second or more. Most preferably, the range of the rotational viscosity coefficient γ1 is 30 to 60 mPa·second.

[0060] Preferably, the thickness (cell thickness) of the liquid crystal layer 160 is 100 nm to 10 μm, more preferably, the cell thickness is 500 nm to 5 μm, and further preferably, 1 μm to 3 μm.

[0061] Alignment films 141 and 142 are disposed on both sides (observation side and back side) of the liquid crystal layer 160. Furthermore, an insulating film may be disposed between the alignment film and the electrode. In the polarization module 11 according to the embodiment, an insulating film 131 and an alignment film 141 are disposed in order from the electrode side between the first electrode 121 and the liquid crystal layer 160, and an insulating film 132 and an alignment film 142 are disposed in order from the electrode side between the second electrode 122 and the liquid crystal layer 160.

[0062] The orientation films 141 and 142 have a function of controlling the orientation of the liquid crystal molecules contained in the liquid crystal layer 160. When the voltage applied to the liquid crystal layer 160 is less than the threshold voltage (including no voltage applied), the orientation of the liquid crystal molecules in the liquid crystal layer 160 is controlled mainly by the action of the orientation films. As materials for the orientation films 141 and 142, materials commonly used in the field of liquid crystal display panels such as polymers having polyimide in the main chain, polymers having polyamic acid in the main chain, and polymers having polysiloxane in the main chain can be used.

[0063] The insulating films 131 and 132 are preferably inorganic insulating films, for example. As inorganic insulating films, for example, inorganic films (relative dielectric constant ε = 5 to 7) such as silicon nitride (SiNx) and silicon oxide (SiO2) and laminated films thereof can be cited. The thickness of each insulating film is not particularly limited, for example, preferably greater than 10 nm and less than 500 nm. More preferably, the thickness of each insulating film is greater than 30 nm and less than 300 nm.

[0064] The phase difference plate 120 combined with the optical stack 110 only needs to have an in-plane phase difference Ro or a thickness direction phase difference Rth. The phase difference plate 120 is preferably a uniaxial phase difference plate having an in-plane phase difference Ro. Preferably, the absolute value |Ro| of the in-plane phase difference Ro is greater than 50nm. More preferably, the absolute value |Ro| is greater than 80nm, more preferably greater than 100nm. In addition, the absolute value |Ro| is preferably less than 500nm. More preferably, the absolute value |Ro| is greater than 400nm, more preferably greater than 350nm.

[0065] A λ / 4 phase difference plate (also referred to as a λ / 4 plate) or a λ / 2 phase difference plate (also referred to as a λ / 2 plate) is preferable as the phase difference plate 120. In the polarization module 11 according to the embodiment, a λ / 4 plate is used as the phase difference plate 120 as described later.

[0066] The phase difference plate 120 may be a single-layer structure or a stacked structure of two or more layers. When the display panel 12 and the polarization module 11 are combined, the phase difference plate 120 is preferably disposed on the display panel 12 side.

[0067] The thickness of the phase difference plate 120 is not particularly limited, and is, for example, 10 μm or more and 500 μm or less. More preferably, the thickness is 50 μm or more and 200 μm or less.

[0068] The material of the phase difference plate 120 is not particularly limited, and for example, a stretched polymer film, a material with a fixed orientation of a liquid crystal material, a thin plate made of an inorganic material, etc. The method for forming the phase difference plate 120 is also not particularly limited.

[0069] In the case where the phase difference plate 120 is formed by a polymer film, the formation method can use, for example, a solvent casting method, a melt extrusion method, etc. The formation method of the phase difference plate 120 is set to a co-extrusion method, and a plurality of phase difference plates 120 can also be formed at the same time. As long as the desired phase difference is shown by the phase difference plate 120, the phase difference plate 120 can be non-stretched or stretched. The stretching method is not particularly limited. In addition to the roller traction stretching method, the roller compression stretching method, the tenter transverse uniaxial stretching method, the oblique stretching method, and the longitudinal and transverse biaxial stretching method, a special stretching method for stretching under the action of the shrinkage force of the heat shrinkable film can also be used.

[0070] In the case where the phase difference plate 120 is formed of a liquid crystal material, the formation method may be, for example, a method of coating a liquid crystal material on a substrate film subjected to an orientation treatment and fixing the orientation. As long as the desired phase difference is exhibited by the phase difference plate 120, the formation method may also be a method of not subjecting the substrate film to a special orientation treatment, a method of peeling off the substrate film after the orientation is fixed and transferring the processing to other films, etc. Furthermore, the formation method of the phase difference plate 120 may also use a method of not fixing the orientation of the liquid crystal material. Even in the case where the phase difference plate 120 is formed of a non-liquid crystal material, the formation method may use the same formation method as that formed by a liquid crystal material.

[0071] As the phase difference plate 120, a material obtained by stretching a film containing a material having positive intrinsic birefringence (intrinsic refractive index anisotropy) as a component can be appropriately used. As the material having positive intrinsic birefringence, for example, polycarbonate, polysulfone, polyethersulfone, polyethylene terephthalate, polyethylene, polyvinyl alcohol, norbornene, triacetyl cellulose, diethyl cellulose, cycloolefin polymer, etc. can be listed.

[0072] The method for producing the optical layered body 110 and the method for producing the polarization module 11 using the optical layered body 110 and the phase difference plate 120 are not particularly limited, and methods generally used in the field of liquid crystal panels can be used.

[0073] The AR panel driving unit 15 controls application of a voltage to the liquid crystal layer 160 in accordance with control from a controller 20 described later. As a result, the polarization module 11 is switched to a plurality of polarization states.

[0074] In the polarization module 11 according to the embodiment, the optical stack 110 switches the phase difference between λ / 2 and 0. In the polarization module 11 according to the embodiment, a λ / 4 plate is used as the phase difference plate 120, and the slow axis of the optical stack 110 and the slow axis of the phase difference plate 120 are arranged to be orthogonal to each other. Thus, the polarization module 11 according to the embodiment includes switching the phase difference between +λ / 4 and -λ / 4.

[0075] In this case, a polarizing film having a phase difference of -λ / 4 or +λ / 4 is attached to the polarizing glasses 200. As an example, when the phase of +λ / 4 in the polarizing module 11 is set to the first polarization state and the phase of -λ / 4 is set to the second polarization state, a polarizing film having a phase difference of +λ / 4 is attached to the polarizing glasses 200. Thus, when the polarizing module 11 is in the first state (the phase difference switch state is +λ / 4), the phase difference is +λ / 2 (=(+λ / 4)+(+λ / 4)), and the polarizing glasses 200 transmit polarized light. When the polarizing module 11 is in the second state (the phase difference switch state is -λ / 4), the phase difference is 0 (=(-λ / 4)+(+λ / 4)), and the polarizing glasses 200 do not transmit polarized light. When the first polarization state and the second polarization state of the polarizing module 11 in the phase difference switching between +λ / 4 and -λ / 4 are set to be opposite, a polarizing film having a phase difference of -λ / 4 is attached to the polarizing glasses 200.

[0076] The controller 20 has a timing controller 21, a memory 22, an image generating section 23, and a data selector 25. The memory 22 has a storage area 221 for storing first image data D1 inputted from the outside as an image signal Sg1.

[0077] The image generation unit 23 generates the second image data D2 based on the first image data D1 stored in the memory 22. To generate the second image data D2 based on the first image data D1, the image generation unit 23 uses a lookup table (LUT) 24 described later. The image generation unit 23 may be formed by a circuit or may be implemented by software control.

[0078] In the image generating unit 23, generating the second image data D2 based on the first image data D1 is to convert at least a part of the first image data D1 to generate the second image data D2, and the second image data D2 is an image in which the first image can no longer be perceived by being synthesized with the first image. Preferably, the second image data D2 can be an image in which the first image can no longer be perceived by being synthesized with the first image in a state in which the brightness is affected by the responsiveness of the display panel 12. In other words, the second image data D2 is an image displayed on the display panel 12, and the first image can no longer be perceived by the observer A by being synthesized with the first image visually recognized by the observer A. The image generating unit 23 converts the pixel values ​​of predetermined pixels in each pixel shown in the first image data D1 according to a predetermined relationship. The predetermined pixels are, for example, all pixels of the first image. As an example, the second image is an image in which all pixels become specific pixel values ​​(for example, a gray image) by being synthesized with the first image.

[0079] Figure 5 301 and 302 are diagrams showing an example of a first image 301 and a second image 302 . Figure 5The first image 301 is an image of 6×6 dots, in which “A” is represented by black pixels and the other pixels are white pixels. As an example, the image generation unit 23 generates the second image data D2 by inverting the black and white of the first image data D1 used for the first image 301. Figure 5 In the example of FIG. 3 , the second image 302 is an image consisting of 6×6 dots, in which “A” is represented by white pixels and the other pixels are black pixels.

[0080] By alternately irradiating the display panel 12 in a time-division manner Figure 5 When the observer A does not wear the polarized glasses 200, the first image 301 and the second image 302 are perceived as a composite image (gray image) of the first image 301 and the second image 302, and only the first image 301 is visually recognized. When the observer A wears the polarized glasses 200, since the second image 302 is not visually recognized, only the first image 301 is visually recognized. Thus, the first image 301 can be perceived only when the polarized glasses 200 are worn or only by the user wearing the polarized glasses 200.

[0081] LUT24 specifies the correspondence between the pixel values ​​of the first image data D1 and the second image data D2. The image generation unit 23 generates the second image data D2 by converting the pixel value of each pixel of the first image data D1 into the pixel value specified by LUT24. Preferably, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 is determined as follows: using a luminance meter, the grayscale combination of the first image data D1 and the second image data D2 is measured so that the responsiveness of the display panel 12, the responsiveness of the polarization module 11, the overdrive or gamma value of the display panel 12 and the display settings of the display device 10 are the same as those of the display device 10, so that the integrated brightness of each combination is constant. As another example, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 can also be specified by a function or an operation expression. In addition, as another example, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 can also be machine-learned by deep learning or the like, so that the first image data D1 is used as an input value and the second image data D2 is output.

[0082] Figure 6 2 is a diagram showing an example of the LUT 24. The LUT 24 specifies the pixel value 242 of the second image data D2 corresponding to the pixel value 241 of the first image data D1. Specifically, for each of the pixel values ​​0, ... 127, 128, ... 255 of the first image data D1, the pixel value 255, ... X, Y, ... 0 of the second image data D2 is specified.

[0083] The timing controller 21 inputs the synchronization signal Sg2 to the memory 22, the data selector 25, the AR panel driver 15, and the BL driver 17 at a predetermined timing. As an example, the predetermined timing is every frame of the first image data D1 included in the signal Sg1.

[0084] The data selector 25 obtains the first image data D1 stored in the memory 22 and the second image data D2 generated by the image generation unit 23. The data selector 25 alternately outputs the first image data D1 and the second image data D2 to the display panel drive unit 16 at a timing based on the synchronization signal Sg2. As a result, the first image based on the first image data D1 and the second image based on the second image data D2 at a timing based on the synchronization signal Sg2 are alternately displayed on the display panel 12 in a time-division manner. Based on the timing of the synchronization signal Sg2, the first image based on the first image data D1 and the second image based on the second image data D2 are alternately displayed on the display panel 12 in a time-division manner. As an example, the timing based on the synchronization signal Sg2 is every frame. The switching of the display of the first image and the second image is not limited to every frame, as long as the speed is such that the observer A does not perceive the first image and the second image separately and does not feel flickering when not wearing the polarized glasses 200. The switching of the display between the first image and the second image is preferably above 180 Hz.

[0085] Figure 7 1 is a schematic diagram showing a part of the configuration of the display system 100. On the display panel 12, by sequentially applying voltages based on image data to each pixel by the display panel driving unit 16, images are sequentially written in a direction D. The direction D indicates a scanning direction of the display panel 12, and the direction D is a direction from the upper end 12U to the lower end 12D of the display panel 12. That is, images are sequentially written to the display panel 12 from the upper end 12U to the lower end 12D.

[0086] The AR panel driving unit 15 alternately switches the polarization state of the polarization module 11 between the first polarization state and the second polarization state in synchronization with the switching of the first image and the second image on the display panel 12 at the timing based on the synchronization signal Sg2. As an example, the AR panel driving unit 15 switches the polarization state of the polarization module 11 to the first polarization state and the second polarization state for each frame. That is, when the first image is displayed on the display panel 12, the polarization module 11 switches to the first polarization state, and when the second image is displayed on the display panel 12, the polarization module 11 switches to the second polarization state.

[0087] The polarization module 11 is divided into a plurality of segments in the direction D. Figure 7In the example of , the polarization module 11 is divided into an upper section 11A and a lower section 11B. The upper end 11AU of the upper section 11A coincides with the upper end 12U of the display panel 12, and the lower end 11BD of the lower section 11B coincides with the lower end 12D of the display panel 12. The lower end 11AD of the upper section 11A coincides with the upper end 11BU of the lower section 11B, and they coincide with the center of the display panel 12. The AR panel driving unit 15 controls the polarization states of the upper section 11A and the lower section 11B independently.

[0088] The BL driving unit 17 controls the lighting and extinguishing of the backlight 13 at a timing based on the synchronization signal Sg2 . That is, the BL driving unit 17 controls the lighting and extinguishing of the backlight 13 in synchronization with the switching between the first image and the second image in the display panel 12 .

[0089] Specifically, the BL driving unit 17 turns off the backlight source 13 during a first display period in which the first image is displayed on the display panel 12, during a second display period in which the second image is displayed, and during a non-lighting period specified in each display period. The BL driving unit 17 turns on the backlight source 13 during a lighting period other than the non-lighting period of each of the first display period and the second display period.

[0090] The brightness (luminance) of each pixel of the display panel 12 visually recognized by observer A is the amount of light received by observer A from the pixel during the period when the backlight source 13 is turned on. Therefore, the brightness of each pixel of the display panel 12 visually recognized by observer A becomes the integrated value of the brightness change of the pixel during the period when the backlight source 13 is turned on. The integrated value of the brightness during the period when the backlight source 13 is turned on in the pixel is also distinguished from the instantaneous brightness in the pixel, which is called "integrated brightness". By alternately irradiating the first image and the second image from the display panel 12 in a time-division manner, the brightness of each pixel visually recognized by observer A when not wearing polarized glasses 200 becomes the integrated brightness of the first image and the second image during the period when the backlight source 13 of the pixel is turned on.

[0091] Figure 8 and Fig. 9 2 is a diagram for explaining the brightness visually recognized by the observer A when he / she is not wearing the polarized glasses 200. Figure 8 and Fig. 9 In FIG. 1 , the horizontal axis represents the passage of time. The vertical axis represents the brightness of the display panel 12 using grayscale values. Figure 8 and Fig. 9 In the example, the second image data D2 is relative to the first image data D1. Figure 6 The corresponding relationship is specified in the LUT 24. That is, the pixel value of the second image corresponding to the pixel value of 0 grayscale in the first image is 255 grayscale, and the pixel value of the second image corresponding to the pixel value of 255 grayscale in the first image is 0 grayscale.

[0092] exist Figure 8 and Fig. 9 In the figure, time t0-t1, time t1-t2, time t2-t3 and time t3-t4 are all one frame of time T. At time t0-t1 and time t2-t3, a first image is displayed on the display panel 12, and the first image period T1 is set. At time t1-t2 and time t3-t4, a second image is displayed on the display panel 12, and the second image period T2 is set. The polarization state of the polarization module 11 is switched from the second polarization state to the first polarization state at time t0 and t2, and from the first polarization state to the second polarization state at time t1 and t3. In addition, at Figure 8 and Fig. 9 In the above description, it is assumed that the response of the polarization module 11 is fast enough.

[0093] Here, we focus on pixels whose pixel values ​​are 0 grayscale in the first image and pixels whose pixel values ​​are 255 grayscale in the first image. The former pixels are called first object pixels, and the latter pixels are called second object pixels. The first object pixels have a pixel value of 255 grayscale in the second image, and the second object pixels have a pixel value of 0 grayscale in the second image. Figure 8 The curve L1 represents the change in instantaneous brightness of the first object pixel. Fig. 9 The curve L2 represents the change in instantaneous brightness of the first object pixel.

[0094] Reference Figure 8 By switching the display to the first image at time t0, the brightness of the first object pixel changes from the grayscale value before switching (255 grayscale) to 0 grayscale. The object pixel being 0 grayscale means that the irradiation light from the backlight source 13 is shielded. By switching the display from the first image to the second image at time t1, the brightness of the first object pixel changes from 0 grayscale to 255 grayscale of the second image. The object pixel being 255 grayscale means that the irradiation light from the backlight source 13 is transmitted.

[0095] Reference Fig. 9 By switching the display to the first image at time t0, the brightness of the second object pixel changes from the grayscale value before switching (0 grayscale) to 255 grayscale. By switching the display from the first image to the second image at time t1, the brightness of the second object pixel changes from 255 grayscale to 0 grayscale of the first image.

[0096] When the display panel 12 is a liquid crystal display, a time lag occurs from the grayscale of the target pixel from the start time of the display switching to the grayscale after the switching, or until the grayscale close to the grayscale after the switching stabilizes. The time lag is caused by the responsiveness of the display panel 12, etc. For example, the curve L1 ( Figure 8) After the first object pixel shown in FIG. 1 is switched to display at time t0, the grayscale gradually decreases from 255 during the first image period T1 and stabilizes at a grayscale close to 0. In the period before reaching the grayscale close to 0, the pixel value of the first object pixel changes at a grayscale greater than 0. In addition, when the display is switched at time t1, the grayscale gradually increases in the second image period T2 and stabilizes at a grayscale close to 255. In the period before reaching the grayscale close to 255, the pixel value of the first object pixel changes at a grayscale less than 255. Therefore, after switching the image displayed on the display panel 12, it is sometimes difficult for the brightness of the display panel 12 to stabilize.

[0097] When the brightness of the backlight source 13 during the lighting period V2 is constant, the brightness of the first object pixel visually recognized by the observer A when not wearing the polarized glasses 200 is the integral value of the lighting period V2 in the curve L1. The integral value of the lighting period V2 in the curve L1 is Figure 8 The area S1 is shaded in the middle. For the second object pixel, the brightness visually recognized by the observer A when not wearing the polarized glasses 200 is the integral value of the lighting period V2 in the curve L2. The integral value of the lighting period V2 in the curve L2 is Fig. 9 The area S2 is shown in the shaded area.

[0098] For the first object pixel, when the brightness of the first object pixel in the second image is 255 grayscale, the brightness visually recognized by the observer A when not wearing the polarized glasses 200 is maximum. For the second object pixel, when the brightness of the second object pixel in the second image is 0 grayscale, the brightness visually recognized by the observer A when not wearing the polarized glasses 200 is minimum.

[0099] Since the pixel values ​​of each pixel of the first image data D1 and the second image data D2 are Figure 6 The corresponding relationship is specified in LUT24, so Figure 8 The area S1 and Fig. 9 Therefore, the maximum brightness of the first object pixel that can be visually recognized by the observer A when not wearing the polarized glasses 200 is equal to the minimum brightness of the second object pixel. That is, LUT24 specifies the pixel value of the second image data D2 relative to the pixel value of the first image data D1 so that the integrated brightness is equal, thereby enabling the observer A to visually recognize the entire image at a specific integrated brightness when not wearing the polarized glasses 200.

[0100] The value defining the relationship between the pixel value of the first image data D1 and the pixel value of the second image data D2 is not limited to Figure 6As another example, the pixel value of the second image data D2 can be obtained by substituting the pixel value of the first image data D1. The LUT 24 can define the relationship between the pixel values ​​of the first image data D1 and the second image data D2 for each of the R, G, and B pixels, or can define the relationship between the pixel values ​​of the first image data D1 and the second image data D2 for each of the R, G, and B pixels.

[0101] LUT24 does not need to define the correspondence between the pixel values ​​of the second image data D2 and all the pixel values ​​of the first image data D1, as long as at least a portion of the pixel values ​​are defined. For example, LUT24 can define the correspondence of the second image data D2 for a plurality of pixel values ​​less than all the pixel values ​​of the first image data D1, and other pixel values ​​can be obtained by linear interpolation or the like. In addition, LUT24 can be prepared for each temperature, and LUT24 corresponding to the temperature on the display panel 12 can be used. Alternatively, LUT24 for each specific temperature can be prepared and used for linear interpolation according to the temperature on the display panel 12.

[0102] The backlight source 13 divides the light emitting surface into a plurality of segments ( Figure 7 ). The BL driving unit 17 controls the lighting / extinguishing of each segment of the backlight source 13 independently. Figure 7 In the example of , the backlight source 13 is divided into eight groups of the first segment 13A to the eighth segment 13H. The first segment 13A is closest to the upper end 12U of the display panel 12, and the eighth segment 13H is closest to the lower end 12D of the display panel 12. In addition, the first segment 13A to the fourth segment 13D overlap with the upper segment 11A of the polarization module 11 in a plan view, and the fifth segment 13E to the eighth segment 13H overlap with the lower segment 11B of the polarization module 11 in a plan view.

[0103] Fig.10 This is a schematic diagram for explaining the relationship between the display of the display panel 12 , the polarization state of the polarization module 11 , and the lighting state of the backlight 13 in the display system 100 . Fig.10 The horizontal axis represents the passage of time. Fig.10 The vertical axis (Y axis) indicates the position of the polarization module 11, the display panel 12 and the backlight 13 in the direction D. The position 0 (Y=0) of the vertical axis Y is set to the lower end 12D of the display panel 12 and the lower end 11BD of the lower segment 11B. The negative direction of the Y axis coincides with the direction D.

[0104] On the display panel 12 , the display panel driving section 16 sequentially applies voltages based on image data from the upper end 12U to the lower end 12D in a time period T of one frame, thereby writing an image. Fig.10The writing direction E indicated by the arrow represents the writing position and timing in the display panel 12. The first image 301 starts writing from the upper end 12U of the display panel 12 at times t0 and t2, and finishes writing at the lower end 12D of the display panel 12 at times t1 and t3 after time T. The first image 302 starts writing from the upper end 12 of the display panel 12 at times t1 and t3, and finishes writing at the lower end 12D of the display panel 12 at times t2 and t4 after time T. Therefore, at the start times t0 and t2 of writing the first image 301, the second image 302 before switching is displayed instead of the first image 301 below the upper end 12U of the display panel 12. In addition, at the start times t1 and t3 of writing the first image 302, the first image 301 before switching is displayed instead of the first image 302 below the upper end 12U of the display panel 12.

[0105] The AR panel driving unit 15 offsets and switches the polarization states of the upper segment 11A and the lower segment 11B in the order of direction D based on the synchronization signal Sg2 from the timing controller 21. In this example, the AR panel driving unit 15 offsets the lower segment 11B by half a frame (T / 2) from the upper segment 11A to switch the polarization state.

[0106] Specifically, the AR panel driving unit 15 switches the polarization state of the upper segment 11A after a time difference dt1 (dt1 < T) from the start of writing an image to the display panel 12. After that, the AR panel driving unit 15 offsets by half a frame (T / 2) to switch the first polarization state of the lower segment 11B. In Fig.10 this example, as an example, the time difference dt1 is set to a period of half a frame (T / 2) (dt1 = T / 2).

[0107] The BL driving unit 17 sequentially lights the first segment 13A to the eighth segment 13H of the backlight 13 in the order along the direction D based on the synchronization signal Sg2 from the timing controller 21. In this example, for each of the first segment 13A to the eighth segment 13H, the BL driving unit 17 turns off the non-lighting period V1 from the start time point of writing at the corresponding position of the display panel 12, and then lights it. The positions of the display panel 12 corresponding to the respective segments of the backlight 13 correspond to the regions where the respective segments of the backlight 13 overlap when viewed from above in the screen of the display panel 12.

[0108] Specifically, in the period from the start time t0 of writing the first image 301 to the start time t1 of writing the second image 302 (first image period T1, which is equivalent to the length T of 1 frame), the BL driving unit 17 turns off the first segment 13A during a prescribed period (non-lighting period V1) starting from the time t0, and after the non-lighting period V1, turns on the first segment 133A only during the lighting period V2. The same applies to the segments 13B to 13H. That is, in the period from the start time t0 of writing the first image 301 to the start time t1 of writing the second image 302 (a period equivalent to the length T of 1 frame), the BL driving unit 17 turns off the segment corresponding to the position during the initial prescribed period (a period of the same length as the non-lighting period V1), and then turns on the segment. Fig.10 In FIG. 1 , the lighting periods of the segments 13A to 13H when the first image 301 is sequentially written along the direction D from the start time t0 are represented by the shaded portions M1A to M1H, respectively. Fig.10 As shown, the segments 13A to 13H of the backlight 13 are sequentially turned on in the direction D for a predetermined period (a period having the same length as the lighting period V2 of the first segment 13A), and are turned off in other periods.

[0109] The non-lighting period at each position in the direction D of the display panel 12 corresponding to the segments 13A to 13H, respectively (for example, the period V1 of the first segment 13A), for example, is a period starting from the start time point of writing the image to the area of ​​the display panel 12 that overlaps the segments when viewed from above (for example, the moment t0 for the first segment 13A), and is shorter than the first image period T1. The non-lighting period is the period required for the pixel value of each pixel to reach the grayscale after switching, or the period until it stabilizes at a grayscale close to that after switching, that is, a period equivalent to the above-mentioned time delay. As an example, the length of the non-lighting period can be determined based on characteristics such as the responsiveness of the display panel 12, and can also be determined based on the measurement results of the brightness under specific conditions, etc.

[0110] During the period from the start time t1 of writing the second image 302 to the start time t2 of writing the first image 301 (a period corresponding to the length T of 1 frame), the period from the start time t2 of writing the first image 301 to the start time t3 of writing the second image, and the period from the start time t3 of writing the second image 302 to the start time t4 of writing the first image 301, the BL driving unit 17 starts writing images to the areas corresponding to the segments of the backlight source 13 at the corresponding positions of the display panel 12 for the segments 13A to 13H, and then turns them off for a specified period (a period corresponding to the length of the non-lighting period V1), and then turns on the segments for a period corresponding to the lighting period V2. Fig.10In the figure, the lighting periods of segments 13A to 13H when the second image 302 is written sequentially from the starting time t1 are represented by shaded portions M2A to M2H, respectively. The lighting periods of segments 13A to 13H when the first image 301 is written sequentially from the starting time t2 are represented by shaded portions M3A to M3H, respectively. The lighting periods of segments 13A to 13H when the second image 302 is written sequentially from the starting time t3 are represented by shaded portions M4A to M4H, respectively.

[0111] The lighting periods M1A-H, M2A-H, M3A-H, and M4A-H of the segments 13A-13H are included in the period when the first image 301 is written and the polarization module 11 is in the first polarization state at the corresponding position of the display panel 12, or when the second image 302 is written and the polarization module 11 is included in the period when the second polarization state is included. Thus, the first image 301 or the second image 302 is illuminated at each position in the direction D of the display panel 12 with stable brightness.

[0112] Figures 11 to 13 1 is a flowchart showing an example of a method for controlling the display device 10 in the display system 100. The memory 22 stores first image data D1 input from the outside as an image signal Sg1. As an example, Figure 11 to Figure 13 The control starts when the display of the first image data D1 is instructed by an input device (not shown) or the like. As an example, the instruction to display may include a designation of whether to display the first image data D1 as a secret image or as a normal display. As another example, the display system 100 may include information of a secret image in the first image data D1 and information of reading secret information from the first image data D1. Fig.11 And~ Fig.13 control.

[0113] The image generator 23 generates second image data D2 based on the first image data D1 stored in the memory 22 (step S101), and inputs the second image data D2 to the data selector 25. The timing controller 21 outputs a synchronization signal Sg2 for each frame of the first image data D1 included in the signal Sg1.

[0114] At the timing indicated by the synchronization signal Sg2, the data selector 25 starts writing the first image on the display panel 12 by outputting a control signal to the display panel driver 16 so that the first image is displayed on the display panel 12 according to the first image data D1 stored in the memory 22 (step S103). The AR panel driver 15 switches the upper segment 11A of the polarization module 11 to the first polarization state based on the timing indicated by the synchronization signal Sg2 (step S105). Fig.10In the example of step S105, the AR panel driving unit 15 switches the upper segment 11A to the first polarization state after the time difference dt after the display panel 12 starts writing the first image.

[0115] For each segment 13A to 13H of the backlight source 13, the BL driving unit 17 sequentially lights up the segments 13A to 13H only during the lighting period after a non-lighting period of a predetermined length has elapsed since the writing of the first image started at the corresponding position of the display panel 12, and then turns them off. That is, for the first segment 13A, the BL driving unit 17 lights up the segments 13A only during the lighting period V2 after a non-lighting period V1 has elapsed since the writing of the first image started at the corresponding position of the display panel 12, and then turns them off (step S107).

[0116] exist Fig.10 In the example, since the first segment 13A is turned off at a time (dt+T / 2) from when the display panel 12 starts writing the first image, the AR panel drive unit 15 switches the lower segment 11B to the first polarization state at this timing (step S109). Fig.10 In the example, at the timing when the first segment 13A is turned off (time t1), one frame of time has passed since the first image was written to the display panel 12. Therefore, the data selector 25 outputs a control signal to the display panel drive unit 16 based on the synchronization signal Sg2, so that the display panel 12 displays the second image according to the second image data D2. Thus, the writing of the second image starts on the display panel 12 (step S111). That is, in the area illuminated by the first segment 13A of the backlight source 13, after the lighting of the first segment 13A ends, the rewriting from the first image to the second image is performed. The same is true for the second segment 13B to the eighth segment 13H.

[0117] Next, for the second segment 13B, the BL driving unit 17 lights up only during the lighting period M1B after a non-lighting period V1 (a period equivalent to the length of V1, the same below) has passed since the writing of the first image started at the corresponding position of the display panel 12, and then turns it off (step S113). For the third segment 13C to the fifth segment 13E, the BL driving unit 17 sequentially lights up only during the lighting periods M1C, M1D, and M1E after a non-lighting period has passed since the writing of the first image started at the corresponding position of the display panel 12, and then turns it off (steps S115, 117, 119).

[0118] exist Fig.10 In the example of , when the fifth segment 13E turns off, one frame has passed since the upper segment 11A of the polarization module 11 switched to the first polarization state. Therefore, the AR panel driving unit 15 switches the upper segment 11A to the second polarization state (step S121).

[0119] Next, for the sixth segment 13F to the eighth segment 13H, the BL driving unit 17 sequentially lights up the segments only during the lighting periods M1F, M1G, and M1H after the non-lighting period has passed since the writing of the first image started at the corresponding position of the display panel 12, and then turns them off (steps S123, 125, and 127). In addition, for the first segment 13A, the BL driving unit 17 lights up the segments only during the lighting period M2A after the non-lighting period has passed since the writing of the second image started at the corresponding position of the display panel 12, and then turns them off (step S131).

[0120] exist Fig.10 In the example, since the time when the first segment 13A is extinguished has passed since the writing of the second image on the display panel 12 began (dt+T / 2), the AR panel drive unit 15 switches the lower segment 11B to the second polarization state (step S133). In addition, when displaying the next image ("Yes" in step S134), the image generation unit 23 generates the second image data D2 based on the first image data D1 stored in the memory 22 (step S135), and inputs the second image data D2 to the data selector 25. The timing controller 21 outputs the synchronization signal Sg2 based on the first image data D1 contained in the signal Sg1. At the timing shown by the synchronization signal Sg2, the data selector 25 starts writing the first image on the display panel 12 by outputting a control signal to the display panel drive unit 16 so that the first image is displayed on the display panel 12 according to the first image data D1 stored in the memory 22 (step S137).

[0121] Next, for the second segment 13B to the fifth segment 13E, the BL driving unit 17 starts writing the second image at the corresponding position of the display panel 12 in sequence, and after a non-lighting period, respectively lights up M2B, M2C, M2D, and M2E only during the lighting period, and then turns them off (steps S139, 141, 143, and 145).

[0122] exist Fig.10 In the example of , when the fifth segment 13E turns off, one frame has passed since the upper segment 11A of the polarization module 11 was switched to the second polarization state. Therefore, the AR panel driving unit 15 switches the upper segment 11A to the second polarization state (step S147).

[0123] Next, for the 6th segment 13F to the 8th segment 13H, the BL driving unit 17 sequentially starts writing the second image at the corresponding position of the display panel 12, and after the non-lighting period has passed, respectively lights up the segments M2F, M2G, and M2H only during the lighting period, and then turns them off (steps S149, 151, and 153). Thereafter, the process starting from step S107 is repeated.

[0124] When there is no next image to be displayed ("No" in step S134), then, for the second segment 13B to the eighth segment 13H, the BL driving unit 17 starts writing the second image at the position of the corresponding display panel 12 in sequence, and after a non-lighting period, respectively lights up M2B, M2C, M2D, M2E, M2F, M2G, and M2H only during the lighting period, and then turns them off (steps S161, 163, 165, 167, 171, 173, and 179). These processes are the same as the above-mentioned steps S139, 141, 143, 145, 149, 151, and 153. At this time, the AR panel driving unit 15 may switch the polarization state of the upper segment 1A at an appropriate timing (for example, the timing of turning off the fifth segment 13E, etc.) (step S169), or it may not switch. Fig.10 In the example of FIG. 1 , the AR panel driving unit 15 switches the polarization state of the upper segment 11A at the timing when the fifth segment 13E turns off.

[0125] Fig.14 and Fig.15 1 is a schematic diagram showing an example of the display of the display panel 12 , the polarization state of the polarization module 11 , and the image visually recognized by the observer A. FIG. Fig.14 An image perceived when the observer A wears the polarized glasses 200 is shown. Fig.15 An image perceived by the observer A when he does not wear the polarized glasses 200 is shown.

[0126] exist Fig.14 and Fig.15 The horizontal axis represents the passage of time. The first image 301 and the second image 302 are alternately displayed on the display panel 12. In addition, when the first image 301 is displayed, the polarization module 11 switches to the first polarization state, and when the second image 302 is displayed, the polarization module 11 switches to the second polarization state.

[0127] When observer A wears polarized glasses 200 ( Fig.14 ), during the lighting period, the first image 301 is transmitted through the polarized glasses 200 and is visually recognized by the observer A. The second image 302 is not transmitted through the polarized glasses 200 and is not visually recognized by the observer A. Therefore, when the observer A wears the polarized glasses 200, only the first image 301 is visually recognized during the lighting period, and no image is visually recognized when the second image 302 is displayed. As a result, for the observer A wearing the polarized glasses 200, only the first image 301 is visually recognized.

[0128] When observer A does not wear polarized glasses 200 ( Fig.15), during the lighting period, observer A can see both the first image 301 and the second image 302. Therefore, when observer A does not wear polarized glasses 200, the first image 301 and the second image 302 are switched frame by frame and are visually recognized during the lighting period in the frame. As a result, for observer A who does not wear polarized glasses 200, a third image 303 synthesized by the first image 301 and the second image 302 is perceived. For each pixel, the integrated brightness of the first image 301 and the second image 302 when displayed is equal. Therefore, the third image 303 is an image with a uniform grayscale as a whole, such as a gray image.

[0129] By using the display system 100 involved in the embodiment, the first image can be perceived only when the observer A wears the polarized glasses 200. When the observer A does not wear the polarized glasses 200, the first image cannot be perceived because an image different from the first image (the second image) can also be seen. As a result, the first image can be perceived only by a specific user who can wear the polarized glasses 200. Alternatively, the first image can be perceived only at a specific timing when the polarized glasses 200 are worn. The first image can be set as secret information or private information, for example, so as to ensure the confidentiality of such information. In this way, in the display system 100 involved in the present embodiment, the confidentiality of a specific image can be ensured without compromising the user's convenience of use, simply by the presence or absence of the polarized glasses 200.

[0130] In addition, by using the display system 100 according to the embodiment, an image is not emitted during a period when the brightness of the display panel 12 changes, and an image is emitted during a period when the brightness is stable. Therefore, the brightness of the image emitted from the display panel 12 is stable. When the observer A wears the polarized glasses 200, only the first image is emitted to the observer A. At this time, by emitting the first image with stable brightness from the display panel 12, when the observer A wears the polarized glasses 200, the first image can be visually recognized with high image quality.

[0131] Fig.16 and Fig.17 2 is a diagram for explaining the brightness visually recognized by the observer A when wearing the polarized glasses 200. Fig.16 and Fig.17 In FIG. 1 , the horizontal axis represents the passage of time, and the vertical axis represents the brightness of the display panel 12 using grayscale values. Fig.16 The curve L2 and Fig.17 The curve L3 shows the change in instantaneous brightness of a pixel whose pixel value is 255 grayscale (the above-mentioned second target pixel) in the first image 301. Fig.16 The instantaneous brightness change when the second target pixel is located near the upper end 12U of the display panel 12 is shown. Fig.16 The curve L2 and Fig. 9 The curve L2 is the same. Fig.17The instantaneous brightness change when the second target pixel is located near the lower end 12D of the display panel 12 is shown.

[0132] When the second target pixel is located near the upper end 12U of the display panel 12 ( Fig.16 ), the first image 301 is written at times t0 and t2 when writing of the first image is started, and is displayed until times t1 and t3. After the non-lighting period V1 from times t0 and t2, the backlight source 13 is lit. During the lighting period V2, the first image 301 is illuminated. After the time difference dt1, the upper segment 11A changes to the first polarization state. The lighting period V2 is included in the period when the upper segment 11A is in the first polarization state. Therefore, when observer A wears polarized glasses 200, the first image 301 illuminated during the lighting period V2 is visually recognized. Therefore, in this case, the brightness visually recognized by observer A is the integral value of the visually recognized period corresponding to the lighting period V2 in curve L2. The integral value of the lighting period V2 in curve L2 is Fig.16 The area S3 shown by the shaded area.

[0133] exist Fig.10 In the example, the lower segment 11B is offset by half a frame (T / 2) from the upper segment 11A and switches the polarization state. Therefore, the positional relationship of the second object pixel located near the upper end 12U of the display panel 12 relative to the upper segment 11A is equal to the positional relationship of the second object pixel located at the center or below the display panel 12 relative to the lower segment 11B. Therefore, even if the second object pixel is located at the center or below the display panel 12, the brightness visually recognized by the observer A when wearing the polarized glasses 200 becomes Fig.16 The area is S3.

[0134] When the second target pixel is located near the lower end 12D of the display panel 12 ( Fig.17), the first image 301 is written at a time delayed by the amount of writing time from the time t0, t2 when the writing of the first image starts, that is, after the time T of 1 frame from the time t0, t2 (time t1, t3), and displayed until the time t2, t4. After the non-lighting period V1 from the time t1, t3, the backlight source 13 is lit. During the lighting period V2, the first image 301 is illuminated. At the time point of half a frame (T / 2) offset by the time difference dt1 from the time t0 and t2, the lower segment 11B changes to the first polarization state. The lighting period V2 is included in the period when the lower segment 11B is in the first polarization state. Therefore, when the observer A wears the polarized glasses 200, the illuminated first image 301 is visually recognized during the lighting period V2. Therefore, in this case, the brightness visually recognized by the observer A is the integral value of the visually recognized period corresponding to the lighting period V2 in the curve L3. The integral value of the lighting period V2 in the curve L3 is Fig.17 The area S4 shown by the shaded area.

[0135] exist Fig.10 In the example, the lower segment 11B is offset by half a frame (T / 2) from the upper segment 11A and switches the polarization state. Therefore, the positional relationship of the second object pixel located near the lower end 12B of the display panel 12 relative to the lower segment 11B is equal to the positional relationship of the second object pixel located slightly above the center of the display panel 12 relative to the upper segment 11A. Therefore, even in the case where the second object pixel is located slightly above the center of the display panel 12, the brightness visually recognized by the observer A when wearing the polarized glasses 200 becomes Fig.17 The area is S4.

[0136] In the display system 100 according to the present embodiment, the polarization module 11 is divided into a plurality of segments in the direction D, and the polarization state is sequentially shifted and switched along the direction D. Thus, compared with the case where the polarization state of the entire polarization module 11 is uniformly switched at the beginning of each frame, the difference (unevenness) in the brightness of the first image visually recognized by the observer when wearing the above-mentioned polarized glasses can be suppressed.

[0137] In addition, in the display system 100 involved in the present embodiment, the light-emitting surface of the backlight source 13 is divided into a plurality of segments in the direction D, and the segments are sequentially lit one by one in the order along the direction D. In addition, in the display panel 12, during the period of writing an image into an area corresponding to a segment of the backlight source 13, the segment is first extinguished, and during the period of writing the image into the above-mentioned area, the segment is finally lit. During the display period of the first image 301, the lighting period V2 of the light source of the backlight source 13 at each divided position is included in the period during which the first image 301 is written at the corresponding position of the display panel 12 and the polarization module 11 is in the first polarization state. Thus, the first image 301 is irradiated with a stable brightness at each position in the direction D of the display panel 12. The BL driving unit 17 is also controlled in the same manner during the display period of the second image 302, and the second image 302 is irradiated with a stable brightness at each position in the direction D of the display panel 12.

[0138] The timing deviation of switching the polarization state of the upper segment 11A and the lower segment 11B is not limited to 1 / 2 (T / 2) of the time of 1 frame, and may also be other time differences. The timing deviation of switching the polarization state of the upper segment 11A and the lower segment 11B may be set according to the response of the writing of the display panel 12, etc., or may be set according to the response speed of the polarization module 11. In addition, the division of the direction D of the polarization module 11 is not limited to being divided into two. The polarization module 11 may also be divided into a plurality of three or more in the direction D.

[0139] In addition, the timing of turning off and lighting each segment 13A to 13H of the backlight source 13, the length of the turning off period, and the length of the lighting period are not limited to the above examples, and may be other. The length of the turning off period and the length of the lighting period can be set according to the response of the writing of the display panel 12, the response speed of the polarization module 11, etc. In addition, the number of segments of the backlight source 13 is not limited to 8, and it can be divided into more than 8, or less than 7.

[0140] [Second embodiment] The control of the backlight source 13 may include making the amount of light irradiated from the backlight source 13 different between the first image period T1 in which the first image is displayed and the second image period T2 in which the second image is displayed. Making the amount of light irradiated from the backlight source 13 different between the first image period T1 and the second image period T2 means, as an example, making the length of the non-lighting period and the length of the lighting period different between the first image period T1 and the second image period T2. In other words, making the amount of light irradiated from the backlight source 13 different between the first image period T1 and the second image period T2 means making the ratio of the non-lighting period and the lighting period in each image period different between the first image period T1 and the second image period T2. In the display system 100 involved in the second embodiment, the ratio of the non-lighting period and the lighting period is different between the first image period T1 and the second image period T2. As an example, in the display system 100 involved in the second embodiment, according to the characteristics such as the response conditions of the display panel 12 and the polarization module 11, the non-lighting period and the lighting period are made different for each frame.

[0141] Fig.18 1 is a schematic diagram of the display system 100 according to the second embodiment. The display system 100 according to the second embodiment is different from the display system 100 according to the first embodiment ( Figure 1 ) is that the timing controller 21 receives a signal Sg3 from the data selector 25, and the signal Sg3 indicates whether the image data output to the display panel drive unit 16 is the first image data D1 or the second image data D2. In addition, in this case, the display system 100 ( Figure 1 ) is that the timing controller 21 outputs a synchronization signal Sg2-1 corresponding to the signal Sg3 to the BL driving unit 17, instead of the synchronization signal Sg2 in the display system 100 involved in the first embodiment. The synchronization signal Sg2-1 is a signal for determining the timing of displaying the first image or the timing of displaying the second image on the display panel 12.

[0142] Fig.19 1 is a diagram for explaining an example of a non-lighting period and a lighting period in the display system 100 according to the second embodiment. In the display system 100 according to the second embodiment, the BL driving unit 17 makes the non-lighting period and the lighting period different in the first image period T1 and the second image period T2 based on the synchronization signal Sg2-1. Fig.19In the figure, the lighting periods of segments 13A to 13H when the first image 301 is written sequentially from the starting time t0 are represented by shaded portions N1A to N1H, respectively. The lighting periods of segments 13A to 13H when the second image 302 is written sequentially from the starting time t1 are represented by shaded portions N2A to N2H, respectively. The lighting periods of segments 13A to 13H when the first image 301 is written sequentially from the starting time t2 are represented by shaded portions N3A to N3H, respectively. The lighting periods of segments 13A to 13H when the second image 302 is written sequentially from the starting time t3 are represented by shaded portions N4A to N4H, respectively. Fig.19 In the example, for the first segment 13A, the BL driving unit 17 makes the non-lighting period V11 in the first image period T1 longer than the non-lighting period V21 in the second image period T2, and makes the lighting period V12 in the first image period T1 shorter than the lighting period V22 in the second image period T2. As another example, for the first segment 13A, the BL driving unit 17 may make the non-lighting period V11 in the first image period T1 shorter than the non-lighting period V21 in the second image period T2, and make the lighting period V12 in the first image period T1 longer than the lighting period V22 in the second image period T2. The same is true for segments 13B to 13H.

[0143] The length of the non-lighting period and the lighting period in the first image period T1, and the length of the non-lighting period and the lighting period in the second image period T2 can be set according to the characteristics such as the response conditions of the display panel 12 and the polarization module 11. The BL driving unit 17 pre-stores the lengths of the non-lighting period, the lighting period, the non-lighting period, and the lighting period. Based on the synchronization signal Sg2-1, the BL driving unit 17 turns off the backlight source 13 during the corresponding non-lighting period. In addition, the BL driving unit 17 turns on the backlight source 13 for the corresponding lighting period after the non-lighting period. In this way, the amount of light irradiated from the backlight source 13 can be different during the first image period T1 and the second image period T2.

[0144] Making the amount of light irradiated from the backlight source 13 different between the first image period T1 and the second image period T2 is not limited to making the lengths of the non-lighting period and the lighting period different between the first image period T1 and the second image period T2. As another example, making the amount of light irradiated from the backlight source 13 different between the first image period T1 and the second image period T2 may be by making the current value provided to the light source of the backlight source 13 different between the first image period T1 and the second image period T2, or by making the duty cycle of the on and off of the light source (e.g., LED) of the backlight source 13 different, or by making a combination thereof.

[0145] By making the amount of light irradiated from the backlight source 13 different in the first image period T1 and the second image period T2, the integrated brightness during the lighting period of the backlight source 13 can be made different from the case where the amount of light irradiated from the backlight source 13 is the same in the first image period T1 and the second image period T2 (first embodiment). This can be different from the case where the brightness of the image perceived by the observer A when not wearing the polarized glasses 200 is the same as that of the light irradiated from the backlight source 13 in the first image period T1 and the second image period T2.

[0146] Generating the second image data D2 from the first image data D1 in the image generating unit 23 may mean dividing the first image 301 into a plurality of regions and changing the pixel values ​​of the pixels belonging to each region to pixel values ​​of a predetermined correspondence relationship, or using at least two or more correspondence relationships for a plurality of regions.

[0147] Fig. 20 This is a diagram for explaining an example of a method of generating second image data D2 from first image data D1 in the display system 100 according to the second embodiment. The image generating unit 23 uses a correspondence relationship selected from a plurality of correspondence relationships defined in the LUT 24 to change the pixel values ​​of the pixels belonging thereto to a plurality of regions 301a to 301i defined in advance for the first image data D1.

[0148] Fig.21 2 is a diagram showing another example of the LUT 24. The LUT 24 specifies a plurality of data sets 243, 244, 245 of pixel values ​​of the second image data D2 corresponding to the pixel value 241 of the first image data D1. Specifically, Fig.21 LUT24 in the specification specifies a data set (data set A) 243 of pixel values ​​Ua, ..., Va, Wa, ..., Xa, Ya, ..., 0 of the second image corresponding to pixel values ​​0 to 255 of the first image data D1, a data set (data set B) 244 of pixel values ​​Ub, ..., Vb, Wb, ..., Xb, Yb, ..., Zb of the second image, and a data set (data set C) 245 of pixel values ​​Uc, ..., Vc, Wc, ..., Xc, Yc, ..., Zc of the second image.

[0149] Fig. 22 It is used to illustrate Fig.21 A diagram showing the relationship between the data set A specified in the LUT 24. Fig. 22 In the figure, time t0-t1 is the first image period T1, and time t1-t2 is the second image period T2. During the lighting period V12 of the first image period T1, the backlight source 13 is lit, and the first image is irradiated from the display panel 12. During the lighting period V22 of the second image period T2, the backlight source 13 is lit, and the second image is irradiated from the display panel 12.

[0150] The data set A is a combination of pixel values ​​of the first image data D1 and the second image data D2 , which has the minimum brightness visually recognized when the observer A does not wear the polarized glasses 200 . Fig. 22 The curve L5 represents the change in instantaneous brightness of a pixel with a pixel value of 255 grayscale in the first image (the above-mentioned second object pixel). In data set A, the pixel in the second image corresponding to the second object pixel of the first image is set to 0 grayscale. Fig. 22 In the curve L5, the brightness visually recognized by the observer A when not wearing the polarized glasses 200, that is, the integrated brightness is the integrated value of the lighting period V12 and the lighting period V22 in the curve L5, and is an area S5 represented by hatching.

[0151] The grayscale values ​​of the pixels in the second image of the dataset A corresponding to the other pixels in the first image are determined by measuring or calculating so that the integrated brightness is consistent with the area S5. Fig. 22 In the example case, the pixel value of the second image corresponding to the pixel with a pixel value of 0 grayscale in the first image (the first object pixel mentioned above), that is, Ua grayscale, is determined by measuring or calculating so that the integral value (area S6) of the lighting period V12 and the lighting period V22 in the curve L6 as the change of instantaneous brightness becomes area S5.

[0152] For data sets B and C, similarly, the integral brightness of the lighting period V12 and the lighting period V22 when the pixels in the second image corresponding to the second object pixels of the first image are set to the Zb and Zc grayscales, and the grayscale values ​​of the pixels in the second image corresponding to other pixels of the first image are determined by measurement or calculation to make the integral brightness of the lighting period V12 and the lighting period V22 consistent.

[0153] exist Fig.21 In the example, LUT24 specifies data sets A, B, and C of pixel values ​​of the second image data D2 corresponding to the pixel value 241 of the first image data D1, but LUT24 may specify more than four data sets, or may specify two data sets.

[0154] The value defining the relationship between the pixel value of the first image data D1 and the pixel value of the second image data D2 is not limited to Fig.21 As another example, multiple tables may be prepared for each range of pixel values ​​of the first image data D1, or multiple calculation expressions may be prepared. In addition, LUT24 may define the relationship between the pixel value of the first image data D1 and the pixel value of the second image data D2 for each of the color pixels of R, G, and B, or may define the relationship between the pixel value of the first image data D1 and the pixel value of the second image data D2 for each of the color pixels of R, G, and B.

[0155] The number of regions only needs to be 2 or more. As an example, the image generation unit 23 divides the first image 301 into predetermined regions such as 10 pixels x 10 pixels. For example, as 1 pixel x 1 pixel, each pixel of the display panel 12 can also be a region. The size of the region is not limited to a specific size, and can also be determined according to predetermined conditions. The shape of the region is also not limited to a specific shape. The image generation unit 23 selects a data set of pixel values ​​of the second image for each region from the multiple data sets A, B, and C specified in the LUT 24. The image generation unit 23 generates the second image data D2 by converting the pixel values ​​of the pixels of each region belonging to the first image data D1 using the data set of pixel values ​​of the second image determined for the region.

[0156] The method of selecting a data set of pixel values ​​of the second image for each region from the plurality of data sets A, B, and C specified in the LUT 24 is not limited to a specific method. For the first image data D1, at least two of the plurality of data sets A, B, and C may be used. The image generation unit 23 may select randomly or according to a specific user operation. In addition, for example, the image generation unit 23 may also select based on the range of the grayscale of each region, that is, the minimum and maximum values ​​of the grayscale, the average value of the grayscale, etc. Preferably, a data set with a small difference between the pixel value of the first image data D1 and the pixel value of the second image data D2 is selected. Thus, the influence of crosstalk caused by the response can be suppressed, and the first image 301 can be easily visually recognized when the observer A wears the polarized glasses 200. In addition, as another example, the image generation unit 23 may also set a predetermined specific grayscale value (e.g., 0 grayscale) for a specific region among the plurality of regions of the first image data D1, and select a data set of pixel values ​​of the second image used for other regions.

[0157] In the display system 100 according to the first embodiment, when the observer A does not wear the polarized glasses 200, the entire screen of the display panel 12 is visually recognized with the same brightness. In this case, by repeating pixels of different grayscales for each frame at short intervals, when the observer A does not wear the polarized glasses 200, the first image 301 may be instantly perceived due to the line of sight tracking integration effect due to blinking or sudden line of sight movement.

[0158] In contrast, in the display system 100 according to the second embodiment, the pixel values ​​are converted using the correspondence relationship selected for each region of the first image 301 to generate the second image data D2. Therefore, in the display system 100 according to the second embodiment, when the observer A does not wear the polarized glasses 200, the pattern visually recognized is discontinuous, that is, the entire display panel 12 is visually recognized as uneven by the observer A. Therefore, even if there is blinking or a sudden movement of the line of sight, it is difficult to perceive the pattern of the first image 301. As a result, the confidentiality of the first image 301 can be improved.

[0159] In the display system 100 according to the second embodiment, when the observer A does not wear the polarized glasses 200 , he or she perceives the fourth image 305 synthesized from the first image 301 and the second image 304 . Fig.23 This is a schematic diagram showing an example of the display of the display panel 12 and the polarization state of the polarization module 11 in the display system 100 according to the second embodiment, and an image perceived by the observer A, and shows the image perceived when the observer A does not wear the polarization glasses 200 .

[0160] exist Fig.23 In the lighting period from time t0 to t1 and from time t2 to t3, the first image 301 is irradiated from the display panel 12. In addition, at time t0 and t2, the polarization module 11 is switched to the first polarization state. During the lighting period from time t1 to t2 and from time t3 to t4, the second image 304 is irradiated from the display panel 12. At time t1 and t3, the polarization module 11 is switched to the second polarization state.

[0161] When observer A does not wear polarized glasses 200, he perceives fourth image 305 synthesized from first image 301 and second image 304. The integrated brightness of each pixel in regions 301a to 301i of first image 301 and second image 304 is equal. Therefore, regions 301a to 301i of fourth image 305 are specific grayscales such as gray images. Moreover, since the second image 304 is generated using two or more data sets, the integrated brightness of regions 301a to 301i is at least two or more different values. Therefore, regions 301a to 301i of fourth image 305 are not specific grayscales as a whole, but have at least two grayscales.

[0162] Thus, in the display system 100 according to the second embodiment, when the observer A does not wear the polarized glasses 200, various image patterns can be obtained. In addition, the area of ​​the region where the pattern of the first image can be perceived can be made smaller and discontinuous by blinking, etc. Therefore, the confidentiality of the first image 301 can be ensured.

[0163] The size of each region 301a to 301i is not necessarily constant (the same). As another example, the size of each region 301a to 301i may also be determined based on the content included in the first image 301. As an example, when the first image 301 includes text, the size may correspond to the font size. In this case, the image generation unit 23 may also identify the size of the font size based on the information included in the image signal Sg1, and determine the size of each region 301a to 301i based on the correspondence between the size of the pre-stored font size and the size of the region.

[0164] In the above embodiment, an example in which the number of segments of the backlight 13 is 8 has been described, but the number of segments of the backlight 13 is not limited to 8, and the backlight 13 may be divided into 8 or more segments, or may be divided into 7 or less segments.

[0165] [Modification 1] Furthermore, the backlight 13 is not limited to a scanning backlight whose light emitting surface is divided into a plurality of parts, and the backlight 13 may be a backlight whose light emitting surface as a whole is turned off or on.

[0166] Fig.24 This is a schematic diagram for explaining the relationship between the display of the display panel 12 , the polarization state of the polarization module 11 , and the lighting state of the backlight 13 in the display system 100 according to the first modification. Fig.24 The horizontal axis (Y-axis) represents the passage of time. Fig.24 The vertical axis (Y axis) represents the positions of the polarization module 11 , the display panel 12 , and the backlight source 13 in the direction D.

[0167] In the display system 100 according to the first modification, the relationship between the display of the display panel 12 and the polarization state of the polarization module 11 and the lighting state of the backlight source 13 in the display system according to the first embodiment is different ( Fig.10 ), the difference is that the BL driving unit 17 turns off the entire backlight source 13 during the non-lighting period based on the synchronization signal Sg2 from the timing controller 21, and then turns on the entire backlight source 13 only during the lighting period.

[0168] In this case, the lighting period is set as a period during the first image period T1, during which the first image 301 is written in the display panel 12 and the polarization module 11 contains more areas in the first polarization state. Preferably, the lighting period is set as a period during which the first image 301 is written near the center of the screen of the display panel 12 and the polarization module 11 contains more areas in the first polarization state. Alternatively, preferably, the lighting period is set as a period during the first image period T1, during which the first image 301 is written in the display panel 12 and the polarization module 11 contains the most areas in the first polarization state. In addition, the lighting period V2 is set as a period during the second image period T2, during which the second image 302 is written in the display panel 12 and the polarization module 11 contains more areas in the second polarization state. Preferably, the lighting period is set as a period during the second image period T2, during which the second image 302 is written in the display panel 12 and the polarization module 11 contains the most areas in the second polarization state. Fig.24 In the figure, the lighting period V2 of the backlight source 13 during the period from the writing start time t0 of the first image 301 to the writing start time t1 of the second image 302 (a period corresponding to the length T of one frame) is represented by the shaded portion R1. The lighting period of the backlight source 13 during the period from the writing start time t1 of the second image 302 to the writing start time t2 of the first image 301 is represented by the shaded portion R2. The lighting period of the backlight source 13 during the period from the writing start time t2 of the first image 301 to the writing start time t3 of the second image 302 is represented by the shaded portion R3. The lighting period of the backlight source 13 during the period from the writing start time t1 of the second image 302 to the writing start time t2 of the first image 301 is represented by the shaded portion R4.

[0169] Thus, even if the backlight 13 includes a single light source or a plurality of light sources whose on / off are collectively controlled, the brightness of the image emitted from the display panel 12 can be stabilized. Thus, the viewer can visually recognize the image with high image quality.

[0170] [Modification 2] The B1 driving unit 17 may also control the backlight source 13 in synchronization with the timing of display switching together with the so-called local dimming control. Local dimming is a control that divides the backlight source 13 into a plurality of parts and turns on and off necessary parts according to the image displayed on the display panel 12.

[0171] <3. Notes> The present invention is not limited to the above-described embodiment, and various modifications are possible. Description of Reference Numerals

[0172] 10: display device, 11: polarization module, 12: display panel, 13: backlight source, 20: controller, 30: display, 100: display system, 200: polarization glasses, 301: first image, 302: second image, D1: first image data, D2: second image data

Claims

1. A display device, characterized in that: include: Display panel; A polarization module, which is overlapped and arranged on the display panel and can actively switch the polarization state between a first polarization state and a second polarization state; A backlight source, which is overlapped and arranged on the display panel; as well as Controller, The controller is composed of: generating second image data based on the first image data, causing a first image based on the first image data and a second image based on the second image data to be displayed on the display panel in a time-division manner, switching the polarization state of the polarization module synchronously with the timing of the time division, so that the polarization state of the polarization module is the first polarization state when the first image is displayed, and the polarization state of the polarization module is the second polarization state when the second image is displayed, The backlight is controlled to be turned off for a predetermined period and then turned on after starting a display period in which the first image or the second image is displayed on the display panel.

2. The display device according to claim 1, wherein: The polarization module is divided into a plurality of segments along the scanning direction, Switching the polarization state of the polarization module includes switching the polarization states of a plurality of segments of the polarization module with a time difference in a sequence along the scanning direction.

3. The display device according to claim 2, wherein: Controlling the backlight includes lighting the backlight during a period when the polarization states of the plurality of segments of the corresponding polarization module are all in the first polarization state or in the second polarization state.

4. The display device according to claim 2, wherein: Controlling the backlight includes lighting the backlight while the polarization states of the plurality of segments of the polarization module are all in the first polarization state when the first image is displayed or while the polarization states of the plurality of segments of the polarization module are all in the second polarization state when the second image is displayed.

5. The display device according to claim 4, characterized in that The light emitting surface of the backlight source is divided into a plurality of segments, Controlling the backlight source includes: in order along the scanning direction of the display panel, making the multiple segments one by one, starting from the writing of the first image or the second image for the area in the display panel corresponding to each of the multiple segments, extinguished within the specified period, and then lit again.

6. The display device according to claim 1, wherein: Controlling the backlight includes making the amount of light irradiated from the backlight different between a display period in which the first image is displayed and a display period in which the second image is displayed.

7. The display device according to claim 6, characterized in that Making the amount of light emitted from the backlight different includes making the length of the period during which the backlight is turned on different between a display period during which the first image is displayed and a display period during which the second image is displayed.

8. The display device according to claim 1, wherein: The first polarization state enables an observer to visually recognize the first image through polarized glasses worn by the observer. The second polarization state makes it impossible for the observer to visually recognize the second image through the polarized glasses.

9. The display device according to claim 1, wherein: Generating the second image data includes converting the grayscale of the image data into a grayscale having a predetermined corresponding relationship.

10. The display device according to claim 1, wherein: Generating the second image data includes: dividing the image data into a plurality of regions, and changing the grayscale to a predetermined corresponding relationship selected for each region, The corresponding relationships respectively selected for the multiple regions include at least two corresponding relationships.

Images