Display device

Abstract

It is desirable that a display device capable of securing privacy of a specific image without compromising ease of use. A display device (10) is provided with: a display (30); a polarization module (11) that is disposed so as to overlap the display, can be switched to a plurality of polarization states, and can actively switch the polarization state between a first polarization state and a second polarization state; 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 in a time division manner, and switch a polarization state of the polarization module in synchronization with timing of time division. When the first image is displayed, the polarization state of the polarization module is a first polarization state, and when the second image is displayed, the polarization state of the polarization module is a second polarization state.

Description

Technical Field

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

[0002] In some cases, confidential information, personal information, etc. can be displayed only under certain conditions. For example, Japanese Patent Application Laid-Open No. 2001-255844 (hereinafter, Patent Document 1) discloses a system in which a user who views a display using active glasses with shutter lenses can view personal data, and an unauthorized observer who does not have active glasses can only view personal 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 Technical Problems to be Solved by the Invention

[0004] However, in such a system, glasses with shutter lenses are required. Therefore, the glasses used by the user may become large and expensive. In addition, in order to open and close the lens shutter, it is necessary to synchronize the glasses with the display. Therefore, it is necessary to communicate with the user's wearable items wirelessly or wired, which may sometimes impair the user's convenience. Therefore, a display device that can ensure the confidentiality of a specific image without compromising the convenience of use is desired.

[0005] According to a certain embodiment, a display device comprises: a display; a polarization module, which is arranged on the display in an overlapping manner, can be switched to a plurality of polarization states, and can actively switch the polarization state between a first polarization state and a second polarization state; and a controller. The controller is configured as follows: generating second image data based on first image data, displaying a first image based on the first image data and a second image based on the second image data on the display in a time-division manner, and switching the polarization state of the polarization module in synchronization with the timing of the time-division, so that when the first image is displayed, the polarization state of the polarization module is the first polarization state, and when the second image is displayed, the polarization state of the polarization module is the second polarization state.

[0006] Further details are described as embodiments described later. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the configuration of a display system according to the first embodiment. Figure 2 This is a schematic cross-sectional view of a display device including a display system. Figure 3 This is a schematic plan view of the display device as viewed from the observation surface side. Figure 4 This 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 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 diagram for explaining the brightness observed by an observer without wearing polarized glasses. Figure 8 This is a diagram for explaining the brightness observed by an observer without wearing polarized glasses. Fig. 9 This is a flowchart showing an example of a method for controlling a display device in a display system. Fig.10 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.11 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.12 This is a schematic diagram showing a partial configuration of a display system according to the second embodiment. Fig.13 This is a schematic diagram for explaining the relationship between the display of the display panel and the polarization state of the polarization module in the display system according to the second embodiment. Fig.14 It is used to illustrate Fig.13 A graph of the brightness seen by an observer wearing polarized glasses in relation to . Fig.15 It is used to illustrate Fig.13 A graph of the brightness seen by an observer wearing polarized glasses in relation to . Fig.16 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 third embodiment. Fig.17 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 third embodiment. Fig.18 It is a diagram showing another example of LUT. DETAILED DESCRIPTION

[0008] <1. Overview of Display Device> (1) A display device according to an embodiment includes: a display; a polarization module, which is arranged on the display in an overlapping manner and can be switched to a plurality of polarization states, and can actively switch the polarization state between a first polarization state and a second polarization state; and a controller. The controller is configured to generate second image data from 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 in a time-division manner, and switch the polarization state of the polarization module in synchronization with the timing of the time division so that the polarization state is in the first polarization state when the first image is displayed, and in the second polarization state when the second image is displayed.

[0009] The observer uses polarized glasses, which are images displayed on the display, and the images emitted from the polarization module in the first polarization state are transmitted, and the images emitted in the second polarization state are not transmitted. When the observer wears the polarized glasses, only the first image of the first image and the second image switched and displayed on the display in a time-division manner is visually recognized. When the observer does not wear polarized glasses, both the first image and the second image switched and displayed on the display in a time-division manner are visually recognized. The switching of the display of the first image and the second image is performed at a speed that does not feel flickering (flicker) when the observer does not wear polarized glasses. When the observer does not wear 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 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. 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 of this embodiment can ensure the confidentiality of a specific image (first image) without impairing the usability.

[0010] (2) In the display device described in (1), preferably, the first polarization state allows the observer to recognize the first image through polarized glasses worn by the observer, and the second polarization state prevents the observer from recognizing the second image through the polarized glasses. Thus, by using polarized glasses, the confidentiality of the first image can be easily ensured as described above.

[0011] (3) In the display device described in (1) or (2), generating the second image data preferably includes converting the grayscale of the image data into grayscales having a predetermined relationship. Thus, a composite image of the first image and the second image becomes an image of grayscales corresponding to the predetermined relationship.

[0012] (4) in (1) (3) In the display device described above, the second image data is preferably generated by: converting the grayscale of pixels belonging to at least a portion of the image data into grayscales that are different from each other in a predetermined relationship, and setting the grayscale of pixels belonging to an area other than the portion of the image data to a predetermined grayscale that is independent of the grayscale. Thus, the area where the pattern of the first image may appear in the second image is limited to the portion of the image, and does not appear in other areas. 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. Thus, the confidentiality of the first image can be further improved.

[0013] (5) in (1) (4) In the display device described above, the generation of the second image data preferably includes: dividing the image data into a plurality of regions, and changing the grayscale of each region to a predetermined relationship according to the grayscale of pixels belonging to each region. This includes changing the grayscale of each region to a predetermined relationship. As a result, in the composite image of the first image and the second image, the grayscale of each region may be different.

[0014] (6) in (1) (5) In the display device described above, preferably, switching the polarization state of the polarization module includes: dividing the polarization module into a plurality of segments along the scanning direction of the display, and switching the polarization states of the plurality of segments with a time difference in the order along the scanning direction. Thus, compared with the case where the polarization state of the polarization module is uniformly switched as a whole, the area of ​​the display where the rewriting of the first image is not completed, which is included in the range of the first polarization state in the polarization module, can be suppressed. Therefore, compared with the case where the polarization state of the polarization module is uniformly switched as a whole, the difference (unevenness) in the brightness of the first image observed by the observer when wearing the above-mentioned polarized glasses is suppressed.

[0015] <2. Example of display device>

[0016] [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, a television, and the like.

[0017] Figure 2 1 is a schematic cross-sectional view of the display device 10. The display device 10 includes a display 30 and a polarization module 11 arranged to overlap with the display 30. Figure 2In the figure, the polarization module 11 is shown with a gap relative to the display 30, but the polarization module 11 and the display 30 may not have a gap, or may overlap with an extremely small gap. 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 the figure, the backlight source 13 is shown with a gap relative to the display panel 12, but the backlight source 13 and the display panel 12 may not have a gap, or may overlap with a very small gap. The polarization module 11 is arranged in front of the display panel 12 (upper surface). The display device 10 is observed by the observer A from the front side of the display panel 12. Therefore, the front side of the display panel 12 is also the observation side.

[0018] Figure 3 This is a schematic top view of the display device 10 when viewed from the observation surface side. The display device 10, as an example, has a display area 1100 and a frame area 1200 configured as a frame at the outer edge of the display area 1100. The display area 1100 is an area for displaying an arbitrary image, etc. That is, when the backlight source 13 is turned on, it is an area observed from the observation surface side of the display device 10. The frame area 1200 does not transmit light. The display device 10 may not have the frame area 1200.

[0019] The display panel 12 has a plurality of pixels. It is preferred that a plurality of pixels are arranged in a matrix 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 be a structure in which a liquid crystal layer is clamped between a pair of substrates on which pixel electrodes and a common electrode are formed on one substrate, and a voltage is applied between the pixel electrodes and the common electrode so as to apply a lateral electric field (including a fringe electric field) to the liquid crystal layer, thereby performing a display. As another example, the display panel 12 may also be a structure in which a liquid crystal layer is clamped between a pair of substrates on which pixel electrodes are formed on another substrate, and a voltage is applied between the pixel electrodes and the common electrode so as to apply a longitudinal electric field to the liquid crystal layer, thereby performing a display. As a lateral electric field mode, FFS mode, IPS mode, etc. may be cited, and as a longitudinal electric field mode, VA (Vertical Alignment: vertical electric field variation) mode, TN (Twisted Nematic: twisted nematic) mode, etc. may be cited.

[0020] The liquid crystal mode of the display panel 12 is not particularly limited. The liquid crystal mode of the display panel 12 is not particularly limited, and black display can be performed by aligning the liquid crystal molecules in the liquid crystal layer 260 perpendicular to the substrate surface, or by aligning the liquid crystal molecules in the liquid crystal layer 260 in a direction parallel to the substrate surface or in a direction that is neither perpendicular nor parallel. 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 address mode, etc. may also be used.

[0021] 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 these are sandwiched by insulating films 231 and 232. Pixel electrodes and common electrodes not shown are provided on one substrate (substrate 211). On the substrate 211, a black matrix layer (BM layer) 250 and color filter layers 240 (blue color filter layer 240B, red color filter layer 240R, and green color filter layer 240G) regularly arranged between the BM layers are formed. The display panel 12 preferably has a BM layer 250, and the BM layer 250 is arranged in a grid shape when viewed from above.

[0022] 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 and sequentially displays a main image (first image) and a sub-image (second image) described later in a time-division manner under the control of the display panel driving unit 16.

[0023] The backlight 13 has one or more light sources (not shown). Each light source 22 is, for example, an LED (Light Emitting Diode).

[0024] The backlight source 13 is connected to the backlight source (BL) driving unit 17, and is turned on and off by the BL driving unit 17. Multiple light sources not shown in the figure can be turned on and off individually or in a unified manner. When the display panel driving unit 16 switches the first image and the second image described later in a time-division manner and displays them sequentially on the display panel 12, the BL driving unit 17 turns on all the backlights of the display area 1100.

[0025] 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 an 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) on the display panel 12 according to the control of the AR panel driver 15. As an example, when the display panel 12 displays the first image, the polarization module 11 becomes the first polarization state, and when the display panel 12 displays the second image, the polarization module 11 becomes the second polarization state.

[0026] 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 of the display panel 12 is given a polarized 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 of the display panel 12 is given a polarized state by the polarization module 11 and reaches the eyes of observer A without passing through the polarized glasses 200. The display of the display panel 12 entering the field of vision of observer A is called "visual recognition", and the display entering the field of vision is understood in a meaningful way as "perception".

[0027] Polarizing films are attached to both eye parts of the polarized glasses 200. The polarizing films are preferably circular polarizing films. The polarizing films are not limited to circular polarizing films, and may be other types of polarizing films.

[0028] The polarized glasses 200 transmit the image displayed on the display panel 12 for the first polarization state of the polarized module 11, and do not transmit the image displayed on the display panel 12 for the second polarization state. In other words, the first polarization state in the polarized module 11 is a polarization state that allows the first image displayed on the display panel 12 to transmit the polarized glasses 200, and the second polarization state is a polarization state that does not allow the second image displayed on the display panel 12 to transmit the polarized glasses 200.

[0029] Thus, when the observer A is not wearing the polarized glasses 200, he can visually recognize both the first image and the second image that are switched and displayed in a time-division manner on the display panel 12. When the observer A is wearing the polarized glasses 200, he can visually recognize only the first image of the first image and the second image that are switched and displayed in a time-division manner on the display panel 12. The display system 100 does not need 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 need a control mechanism or a power supply.

[0030] 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 and 112, a pair of electrodes 121 and 122, a liquid crystal layer 160, and columnar spacers 151 and 152. More specifically, from the observation side, it includes a first substrate 111, a first electrode 121, a liquid crystal layer 160, a second electrode 122, and a second substrate 112. Between the first substrate 111 and the first electrode 121, a light shielding layer 170 for limiting light shielding of the columnar spacers 151 and 152 is provided, and between the light shielding layer 170 and the first electrode 121, a planarization film 180 is provided. In addition, between the electrodes 121 and 122 and the liquid crystal layer 160, insulating films 131 and 132 and alignment films 141 and 142 are respectively arranged in order from the electrode side.

[0031] 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 surface pressure resistance.

[0032] The first spacer 151 is configured in a floating island shape, which means that the first spacer 151 is configured in a floating island shape in the liquid crystal layer 160. Specifically, when observed in cross section, it means that the liquid crystal layer 160 exists between the first spacer 151 and the first substrate 111 or the second substrate 112. That is, the height of the first spacer 151 is smaller 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.

[0033] 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 can be a value less than 100%, for example,

[0034] 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 (for example, 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 by sandwiching a liquid crystal material, whereby a 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 151, and the other columnar spacers become the second spacer 152.

[0035] As an example of a light shielding unit for limiting the shielding of the first spacer 151 and the second spacer 152, the optical stack 110 has a light shielding portion (also referred to as a light shielding layer) 170. 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 shift around the columnar spacer can be fully suppressed.

[0036] 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.

[0037] 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) formed of a metal, a resin black matrix (also referred to as a resin BM) formed of a resin material, and the like. Examples of the material of the metal BM include metal materials such as aluminum, copper, titanium, molybdenum, chromium, and alloys thereof. Examples of the resin BM include a black resist, preferably a black photosensitive resin. Specifically, examples include a black photosensitive acrylic resin. The light shielding portion 170 may be a single-layer film or a multi-layer film.

[0038] The light shielding portion 170 preferably has a light transmittance of, for example, 0 to 1%. The thickness of the light shielding portion 170 is not particularly limited. For example, the thickness of the light shielding portion 170 is preferably 10 nm to 2 μm. The thickness of the light shielding portion 170 is more preferably 50 nm to 1.5 μm.

[0039] Figure 4 It 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 the 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 932.4 μm×932.4 μm square when looking down on the liquid crystal layer 160 is taken as the basic unit (also called a repeating unit) U, and the polarization module 11 is constructed so that the basic unit U is repeatedly configured in the entire area of ​​the liquid crystal layer 160. Figure 4 In the figure, one basic unit U is surrounded by a dotted line. In the basic unit U, two second spacers 152 with a diameter φ of about 15.3 μm and a height of 1.6 μm are arranged, and 44 first spacers 151 with a short diameter of about 15 μm, a long diameter of 40 μm, a height of 1.3 μm, and a quarter-circle corner are arranged.

[0040] In order to obtain the unit U, first, the interval (gap) between the first spacer 151 and other first spacers 151 adjacent thereto in the horizontal direction is 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 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 3) are removed from the left side 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 (3) 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 arranged here is arranged so as to be aligned with the adjacent first spacers 151a and 151b in the middle position in the vertical direction.

[0041] Furthermore, the third first spacer 151 (1 piece) is also removed from the right side of the fourth row, 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.

[0042] 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, for example, an organic insulating film. As the organic insulating film, 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 used. Specifically, organic films such as acrylic resins, polyimide resins, and novolac resins, and laminates thereof can be cited. The thickness of the planarization film 180 is not particularly limited, and for example, it is preferably not less than 10 nm and not more than 5 μm. The thickness of the planarization film 180 is more preferably not less than 30 nm and not more than 3 μm.

[0043] The first substrate 111 and the second substrate 112 are preferably transparent substrates. The transparent substrate may be any substrate as long as it is transparent to visible light, for example, a glass substrate, a plastic substrate, etc.

[0044] The first electrode 121 and the second electrode 122 are preferably transparent electrodes, which can 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.

[0045] 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 solid-surface electrodes, but may also be patterned electrodes.

[0046] As an example, the polarizing 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. 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 are also a type of ECB mode in the sense that the birefringence of the liquid crystal layer is controlled by applying a voltage. In the polarizing module 11 of 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.

[0047] The liquid crystal layer 160 is composed of a liquid crystal material including liquid crystal molecules 1601. A voltage is applied to the liquid crystal layer 160, and the orientation state of the liquid crystal molecules 1601 is changed according to the applied voltage, thereby controlling the amount of light transmitted. 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.

[0048] The liquid crystal molecules 1601 preferably have 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)

[0049] The liquid crystal molecules 1601 may also have a negative dielectric anisotropy (Δε). In the polarization module 11 of 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 becomes the direction of the slow axis.

[0050] The liquid crystal molecules 1601 also preferably satisfy the following formula (1). K11≧γ1 / {(Δε)2×1.3×1011} Formula (1) (In the formula, K11 represents the splay elastic constant (pN) of the liquid crystal molecule 1601. In the formula, γ1 represents the rotational viscosity coefficient of the liquid crystal material (mPa·second). Δε represents the dielectric constant anisotropy of the liquid crystal molecule 1601.)

[0051] 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 can provide a polarization module 11 capable of following faster image switching.

[0052] The dielectric anisotropy Δε of the liquid crystal molecule 1601 only needs to be within the range satisfying the above formula (1). From the viewpoint of achieving high-speed response, it is preferably greater than 0.1. 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.

[0053] From the perspective of achieving high-speed response, the liquid crystal molecule 1601 preferably has a flexure elastic constant K11 of 5 pN or more. More preferably, the flexure elastic constant K11 is 10 pN or more. In addition, from the same perspective, the flexure elastic constant K11 is preferably 30 pN or less. More preferably, the flexure elastic constant K11 is 20 pN or less. The most preferred range of the flexure elastic constant K11 is 10 to 20 pN.

[0054] From the viewpoint of achieving high-speed response, the liquid crystal material constituting the liquid crystal layer 160 preferably has a rotational viscosity coefficient γ1 of 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. The most preferred range of the rotational viscosity coefficient γ1 is 30 to 60 mPa·second.

[0055] The thickness (cell thickness) of the liquid crystal layer 160 is preferably 100 nm to 10 μm, more preferably 500 nm to 5 μm, and even more preferably 1 μm to 3 μm.

[0056] 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 of 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.

[0057] The alignment films 141 and 142 have a function of controlling the alignment of liquid crystal molecules included in the liquid crystal layer 160. When the voltage applied to the liquid crystal layer is less than the threshold voltage (including no voltage application), the alignment films mainly function to control the alignment of liquid crystal molecules in the liquid crystal layer 160. As the material of the alignment films 141 and 142, a common material in the field of liquid crystal display panels such as a polymer having polyimide in the main chain, a polymer having polyamic acid in the main chain, and a polymer having polysiloxane in the main chain can be used.

[0058] The insulating films 131 and 132 are preferably inorganic insulating films, for example. As the inorganic insulating film, for example, silicon nitride (SiN x ), inorganic films such as silicon oxide (SiO2) (relative dielectric constant ε = 5 to 7), and laminated films thereof. The thickness of each insulating film is not particularly limited, and is preferably 10 nm to 500 nm. More preferably, the thickness of each insulating film is 30 nm to 300 nm.

[0059] The phase difference plate 120 combined with the optical laminate 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. The absolute value |Ro| of the in-plane phase difference Ro is preferably greater than 50nm. More preferably, the absolute value |Ro| is greater than 80nm, and further preferably greater than 100nm. In addition, the absolute value |Ro| is preferably less than 500nm. More preferably, the absolute value |Ro| is less than 400nm, and further preferably less than 350nm.

[0060] The phase difference plate 120 is preferably 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). In the polarization module 11 of the embodiment, a λ / 4 plate is used as the phase difference plate 120 as described later.

[0061] The phase difference plate 120 may have 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.

[0062] The thickness of the phase difference plate 120 is not particularly limited, but is preferably, 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.

[0063] The material of the phase difference plate 120 is not particularly limited, and for example, a material obtained by stretching a polymer film, a material obtained by fixing the 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 not particularly limited.

[0064] In the case where the phase difference plate 120 is formed by a polymer film, the forming method may be, for example, a solvent casting method, a melt extrusion method, or the like. The forming method of the phase difference plate 120 may be a co-extrusion method, and a plurality of phase difference plates 120 may be formed simultaneously. Even if the phase difference plate 120 exhibits a desired phase difference, the phase difference plate 120 may be unstretched or stretched. There is no particular limitation on the stretching method. In addition to the inter-roll stretching method, the inter-roll compression stretching method, the tenter transverse uniaxial stretching method, the inclined stretching method, and the longitudinal and transverse biaxial stretching method, a special stretching method for stretching under the action of the shrinkage force of a heat shrinkable film may also be used.

[0065] In addition, when 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 phase difference plate 120 exhibits a desired phase difference, the formation method may also be a method of not subjecting the substrate film to a special orientation treatment, or a method of peeling off the substrate film after the orientation is fixed and transferring it to another film. Moreover, the formation method of the phase difference plate 120 may also use a method of not fixing the orientation of the liquid crystal material. In addition, when the phase difference plate 120 is formed of a non-liquid crystal material, the formation method may also use the same formation method as when it is formed of a liquid crystal material.

[0066] As the phase difference plate 120, a phase difference layer obtained by stretching a film containing a material having positive intrinsic birefringence (intrinsic refractive index anisotropy) as a component can be appropriately used. Examples of materials having positive intrinsic birefringence include polycarbonate, polysulfone, polyethersulfone, polyethylene terephthalate, polyethylene, polyvinyl alcohol, norbornene, triacetyl cellulose, diethyl cellulose, cycloolefin polymers, and the like.

[0067] The method for producing the optical layered body 110 and the method for producing the polarizing module 11 using the optical layered body 110 and the phase difference plate 120 are not particularly limited, and methods commonly used in the field of liquid crystal display panels can be used.

[0068] 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. Thus, the polarization module 11 is switched to a plurality of polarization states.

[0069] In the polarization module 11 of the embodiment, the optical stack 110 performs phase difference switching between λ / 2 and 0. In the polarization module 11 of the embodiment, the phase difference plate 120 used is a λ / 4 plate, 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 involved in the embodiment can perform phase difference switching between +λ / 4 and -λ / 4.

[0070] In this case, a polarizing film of a phase difference of -λ / 4 and a phase difference of +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 of 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 switching 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 switching state is -λ / 4), the phase difference is 0 (=(-λ / 4)+(λ / 4)), and the polarizing glasses 200 do not transmit polarized light. In the case where the first polarization state and the second polarization state of the polarizing module 11 in the phase difference switch of +λ / 4 and -λ / 4 are opposite, a polarizing film of a phase difference of -λ / 4 may be attached to the polarizing glasses 200.

[0071] The controller 20 includes a timing controller 21, a memory 22, an image generating section 23, and a data selector 25. The memory 22 includes a storage area 221 for storing first image data D1 input from the outside as an image signal Sg1.

[0072] The image generation unit 23 generates the second image data D2 from the first image data D1 stored in the memory 22. To generate the second image data D2 from 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 constituted by a circuit or may be realized by software control.

[0073] The timing controller 21 inputs the synchronization signal Sg2 to the memory 22, the data selector 25, and the AR panel driving unit 15 at a predetermined timing. As an example, the predetermined timing is each frame of the first image data D1 included in the signal Sg1.

[0074] 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 the timing of the synchronization signal Sg2. Thus, the first image and the second image data D2 are alternately displayed on the display panel 12 in a time-division manner based on the timing of the synchronization signal Sg2. 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 it is a speed at which the first image and the second image are not perceived separately and flickering is not felt when the observer A does not wear the polarized glasses 200. The switching of the display of the first image and the second image is preferably above 180 Hz.

[0075] 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 time 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, at the moment when the first image is displayed on the display panel 12, the polarization module 11 switches to the first polarization state, and at the moment when the second image is displayed on the display panel 12, the polarization module 11 switches to the second polarization state.

[0076] Generating the second image data D2 from the first image data D1 in the image generating unit 23 means converting at least a portion of the first image data D1 to generate the second image data D2, wherein the second image data D2 is an image in which the first image cannot be perceived by being synthesized with the first image. Preferably, the second image data D2 may also be an image in which the first image is not perceived by being synthesized with the first image in a state where there is a brightness influence caused 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, which is synthesized with the first image recognized by the observer A so that the observer A cannot perceive the first image. The image generating unit 23 converts the pixel values ​​of predetermined pixels in each pixel shown in the first image data D1 in 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.

[0077] Figure 5 301 and 302. FIG. Figure 5 The first image 301 is an image in which "A" is represented by black pixels in a 6×6 dot matrix and the other pixels are white pixels. As an example, the image generation unit 23 generates the second image data D2 by performing a black-and-white inversion on the first image data D1 used for the first image 301. Figure 5 In the example of , the second image 302 is an image in which "A" is represented by black pixels among 6×6 dots and the other pixels are white pixels.

[0078] Will Figure 5 The first image 301 and the second image 302 are alternately displayed on the display panel 12 in a time-division manner, so that when the observer A does not wear the polarized glasses 200, he perceives the composite image (gray image) of the first image 301 and the second image 302 and recognizes only the first image 301. When the observer A wears the polarized glasses 200, he cannot visually recognize the second image 302, so he only visually recognizes the first image 301. Therefore, 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.

[0079] The LUT 24 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 the LUT 24. Preferably, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 is determined as follows: a combination of grayscales of the first image data D1 and the second image data D2 is measured using a luminance meter so that the integrated brightness of each combination is constant, wherein the first image data D1 and the second image data D2 are displayed with the display settings of the display panel 12, such as the responsiveness of the display panel 12, the responsiveness of the polarization module 11, the overdrive or the gamma value, etc., being the same as those of the display device 10. As another example, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 may be specified by a function or an arithmetic expression. In addition, as another example, the correspondence between the pixel values ​​of the first image data D1 and the second image data D2 is that the image generating unit 23 may also perform machine learning through deep learning or the like to use the first image data D1 as an input value and output the second image data D2.

[0080] Figure 6 2 is a diagram showing an example of LUT 24. LUT 24 defines pixel values ​​242 of second image data D2 corresponding to pixel values ​​241 of first image data D1. Specifically, for each pixel value 0, ... 127, 128, ... 255 of first image data D1, pixel values ​​255, ... X, Y, ... 0 of second image data D2 are defined.

[0081] 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 within a specified period. Therefore, the brightness of each pixel of the display panel 12 visually recognized by observer A becomes the integral value of the brightness change of the pixel during the specified period. The integral value of the brightness in a pixel during a specified period is also distinguished from the instantaneous brightness in the pixel and is called "integrated brightness". By alternately displaying the first image and the second image on the display panel 12 in time division, the brightness of each pixel observed by observer A when not wearing polarized glasses 200 becomes the integrated brightness of the pixel of the first image and the second image.

[0082] Figure 7 and Figure 8 2 is a diagram for explaining the brightness observed by the observer A when he / she does not wear the polarized glasses 200. Figure 7 and Figure 8 In FIG. 1 , the horizontal axis represents the passage of time. The vertical axis represents the brightness of the display panel 12 in grayscale values. Figure 7 and Figure 8 In the example, the second image data D2 is obtained by comparing the first image data D1 with 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.

[0083] exist Figure 7 as well as Figure 8 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 at time t2-t3, the first image is displayed on the display panel 12 as the first image period T1. At time t1-t2 and at time t3-t4, the second image is displayed on the display panel 12 as the second image period T2. 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, Figure 7 and Figure 8 In this case, the response of the polarization module 11 is set to be sufficiently fast.

[0084] Here, we focus on the pixels whose pixel values ​​in the first image are 0 grayscale and the pixels whose pixel values ​​in the first image are 255 grayscale. 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 7 The curve L1 represents the change in instantaneous brightness of the first object pixel. Figure 8 The curve L2 represents the instantaneous brightness change of the second object pixel.

[0085] Reference Figure 7 , by displaying the brightness of the first object pixel switched 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 is 0 grayscale, which means that the irradiation light from the backlight source 13 is blocked. By displaying the switch 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 is 255 grayscale, which means that the irradiation light from the backlight source 13 is transmitted.

[0086] Reference Figure 8 , the brightness of the second object pixel changes from the grayscale value before the switch (0 grayscale) to 255 grayscale by displaying the switch from the first image to the second image at time t0. By displaying the switch 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.

[0087] Regarding the first object pixel, the brightness recognized by the observer A when not wearing the polarized glasses 200 is the integral value of the curve L1. The integral value of the curve L1 is Figure 7 The area S1 indicated by the hatching in FIG. 1 is shown in FIG. 1 . Regarding the second object pixel, the brightness observed by the observer A when not wearing the polarized glasses 200 is the integral value of the curve L2. The integral value of the curve L2 is Figure 8 The area S2 is shown by the hatched line.

[0088] Regarding the first object pixel, when the brightness of the first object pixel in the second image is 255 grayscale, the brightness observed by the observer A when not wearing the polarized glasses 200 is the maximum. Regarding the second object pixel, when the brightness of the second object pixel in the second image is 0 grayscale, the brightness observed by the observer A when not wearing the polarized glasses 200 is the minimum.

[0089] The pixel value of each pixel of the first image data D1 and the second image data D2 is Figure 6 The corresponding relationship is specified by LUT24, so Figure 7 The area S1 and Figure 8 Therefore, the maximum brightness of the first object pixel and the minimum brightness of the second object pixel that can be recognized when the observer A does not wear the polarized glasses 200 are equal. That is, the pixel value of the second image data D2 is specified by LUT24 so that the integrated brightness is equal, so that when the observer A does not wear the polarized glasses 200, the entire image can be recognized at a specific integrated brightness.

[0090] The method of 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 6 As 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.

[0091] LUT24 does not need to define the correspondence of the pixel values ​​of the second image data D2 for all the pixel values ​​of the first image data D1, but only needs to define it for at least a part of the pixel values. For example, LUT24 may define the correspondence of the second image data D2 for a plurality of pixel values ​​less than all the first image data D1, and obtain other pixel values ​​by linear interpolation or the like. Furthermore, LUT24 may be prepared for each temperature, and LUT24 corresponding to the temperature on the display panel 12 may be used. Alternatively, LUT24 for each specific temperature may be prepared, and linear interpolation may be performed according to the temperature on the display panel 12 for use.

[0092] Fig. 9 1 is a flowchart showing an example of a method for controlling the display device 10 in the display system 100. As an example, Fig. 9 The control starts when the display of the first image data D1 is instructed by an input device (not shown) or the like, and the first image data D1 inputted from the outside as the image signal Sg1 is stored in the memory 22. 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 a normal display. As another example, the information as a secret image included in the first image data D1 may be read from the first image data D1 to be displayed in the display system 100. Fig. 9 control.

[0093] 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.

[0094] The data selector 25 outputs a control signal to the display panel drive unit 16 at the time indicated by the synchronization signal Sg2, 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). In addition, at the same time indicated by the synchronization signal Sg2, the AR panel drive unit 15 sets the polarization module 11 to the first polarization state (step S105).

[0095] If the synchronization signal Sg2 indicating the time of the next frame is received from the timing controller 21 ("Yes" in step S107), the data selector 25 outputs a control signal to the display panel drive unit 16 so that the second image is displayed on the display panel 12 from the second image data D2 (step S109). In addition, at the same time indicated by the synchronization signal Sg2, the AR panel drive unit 15 causes the polarization module 11 to be in the second polarization state (step S111).

[0096] If the synchronization signal Sg2 indicating the time of the next frame is received from the timing controller 21 ("Yes" in step S113), repeat from step S103. That is, until the synchronization signal Sg2 indicating the time of the next frame is not received from the timing controller 21 ("No" in step S107 or "No" in step S113), the data selector 25 outputs a control signal to the display panel drive unit 16 together with the synchronization signal Sg2 from the timing controller 21, so that the display panel 12 alternately displays the first image and the second image. In addition, the AR panel drive unit 15 alternately switches the polarization state of the polarization module 11 to the first polarization state and the second polarization state.

[0097] Fig.10 and Fig.11 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 viewed by the observer A. FIG. Fig.10 2 represents the image perceived by observer A wearing polarized glasses 200 . Fig.11 200 represents the image perceived by the observer A when he is not wearing the polarized glasses 200 .

[0098] exist Fig.10 as well as Fig.11 In the embodiment, at time t0-t1 and time t2-t3, the display panel 12 displays the first image 301. In addition, at time t0 and time t2, the polarization module 11 switches to the first polarization state. Fig.10 as well as Fig.11 In the embodiment, at time t1 to t2 and time t3 to t4, the second image 302 is displayed on the display panel 12. In addition, at time t1 and time t3, the polarization module 11 is switched to the second polarization state.

[0099] When observer A wears polarized glasses 200 ( Fig.10 ), the first image 301 displayed at time t0-t1 and time t2-t3 is seen by observer A through the polarized glasses 200. The second image 302 displayed at time t1-t2 and time t3-t4 is not seen by observer A through the polarized glasses 200. Therefore, when observer A wears the polarized glasses 200, the first image 301 is seen at time t0-t1 and time t2-t3, and cannot be seen at time t1-t2 and time t3-t4. As a result, observer A wearing the polarized glasses 200 only sees the first image 301.

[0100] When observer A does not wear polarized glasses 200 ( Fig.11 ), the first image 301 displayed at time t0-t1 and time t2-t3 and the second image 302 displayed at time t1-t2 and time t3-t4 are also visually recognized by observer A. Therefore, when observer A does not wear polarized glasses 200, the first image 301 and the second image 302 are visually recognized by switching frame by frame. As a result, observer A who does not wear polarized glasses 200 perceives a third image 303 that is a synthesis of the first image 301 and the second image 302. The first image 301 and the second image 302 have the same integrated brightness for each pixel when displayed. Therefore, the third image 303 is an image with an overall uniform grayscale, such as a gray image.

[0101] 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, an image different from the first image (the second image) is also visually recognized, and therefore the first image cannot be perceived. Thus, the first image can be perceived only by a specific user wearing the polarized glasses 200. Alternatively, the first image can be perceived only at a specific moment when the polarized glasses 200 can be worn. The confidentiality of the first image can be ensured, for example, by using secret information or personal information. In this way, in the display system 100 of 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.

[0102] <Second Embodiment> Fig.12 1 is a schematic diagram showing a partial structure of a display system 100 according to the second embodiment. In the display panel 12, a voltage based on image data is sequentially applied to each pixel by the display panel driving unit 16, so that an image is sequentially written in a direction D. The direction D represents 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, an image is sequentially written to the display panel 12 from the upper end 12U to the lower end 12D.

[0103] In the display system 100 according to the second embodiment, the polarization module 11 is divided into a plurality of segments in the direction D. Fig.12 In the example of FIG. 1 , the polarization component 11 is divided into an upper segment 11A and a lower segment 11B. The upper end 11AU of the upper segment 11A coincides with the upper end 12U of the display panel 12, and the lower end 11BD of the lower segment 11B coincides with the lower end 12D of the display panel 12. The lower end 11AD of the upper segment 11A coincides with the upper end 11BU of the lower segment 11B, and they coincide with the center of the display panel 12. The AR panel driving unit (15) independently controls the polarization states of the upper segment 11A and the lower segment 11B.

[0104] Fig.13 This is a schematic diagram for explaining the relationship between 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. Fig.13 The horizontal axis represents the passage of time. Fig.13 The vertical axis (Y axis) indicates the position of the polarization module 11 and the display panel 12 in the direction D. The position 0 (Y=0) of the vertical axis Y is 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.

[0105] In 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 during one frame time T, thereby writing an image. Fig.13 The writing direction E indicated by the arrow represents the writing position and time in the display panel 12. The first image 301 is written from the upper end 12U of the display panel 12 at time t0 and t2, and the writing is completed at the lower end 12D of the display panel 12 at time t1 and t3 after time T. The first image 302 is written from the upper end 12U of the display panel 12 at time t1 and t3, and the writing is completed at the lower end 12D of the display panel 12 at time t2 and t4 after time T. Therefore, at the start time t0 and t2 of writing the first image 301, the first image 301 is not displayed below the upper end 12U of the display panel 12, and the second image 302 before the switching is displayed. In addition, at the start time t1 and t3 of writing the second image 302, the second image 302 is not displayed below the upper end 12U of the display panel 12, and the first image 301 before the switching is displayed.

[0106] At this time, when the AR panel driving unit 15 switches the polarization state of the entire polarization module 11 to the first polarization state at time t0 and t2 according to the synchronization signal Sg2 from the timing controller 21, when the observer A wears the polarization glasses 200, only the upper end 12U of the display panel 12 displays the first image 301, and the screen showing the second image 302 is seen below the upper end 12U. That is, if the entire polarization module 11 is switched to the first polarization state at the same time as the start of writing the first image 301, the first image 301 may not be properly visually recognized.

[0107] In this regard, the AR panel driving unit 15 according to the second embodiment switches the polarization state of the upper segment 11A and the polarization state of the lower segment 11B in a staggered order in the direction D based on the synchronization signal Sg2 from the timing controller 21. In this example, the AR panel driving unit 15 switches the polarization state of the lower segment 11B by staggering half a frame (T / 2) from the upper segment 11A.

[0108] Thus, at least when the upper end 12U of the display panel 12 displays the first image 301, the upper segment 11A is in the first polarization state, and when the observer A wears the polarized glasses 200, the first image 301 can be visually recognized at least at the upper end 12U. On the other hand, at this moment, the lower segment 11B is not switched to the first polarization state but to the second polarization state, so when the observer A wears the polarized glasses 200, the second image 302 that remains displayed can be suppressed from being recognized.

[0109] Preferably, the AR panel driving unit 15 switches the polarization state of the upper segment 11A after a predetermined time from the start of writing an image to the display panel 12. By switching the polarization state of the upper segment 11A after a specified time from the start of writing an image to the display panel 12, when the upper segment 11A is switched to the first polarization state, the area where writing to the display panel 12 is completed increases.

[0110] As an example, the AR panel driving unit 15 switches the upper segment 11A to the first polarization state after a time difference dt1 (dt1 < T) from times t0 and t2. The AR panel driving unit 15 switches the lower segment 11B to the first polarization state after a time difference dt2 (dt2 = dt1 + T / 2) from times t0 and t2, with a half-frame T / 2错开 from the upper segment 11A. Further, the AR panel driving unit 15 switches the upper segment 11A to the second polarization state after a time difference dt1 (dt1 < T) from times t1 and t3. The AR panel driving unit 15 switches the lower segment 11B from times t1 and t3 to the second polarization state after a time difference dt2 (dt2 = dt1 + T / 2), with a half-frame (T / 2)错开 from the upper segment 11A.

[0111] Fig.14 and Fig.15 are diagrams for explaining the brightness visually recognized by the observer A wearing the polarization glasses 200 in the relationship of Fig.13 . In Fig.14 and Fig.15 , the horizontal axis represents the passage of time. The vertical axis represents the brightness of the display panel 12 shown as a gray value. Fig.14 The curve L2 of Fig.15 and the curve L3 of Fig.14 represent the change in the instantaneous brightness of the pixels with a pixel value of 255 gray levels of the first image 301 (the above-mentioned second target pixels). Fig.14 represents the change in the instantaneous brightness when the second target pixel is located near the upper end 12U of the display panel 12. Figure 8 The curve L2 of Fig.15 is the same as the curve L2 of

[0112] In the case where the second target pixel is located near the upper end 12U of the display panel 12 ( Fig.14),The first image 301 is written at times t0 and t2 when writing of the first image starts, and is displayed at times t1 and t3. After a time difference dt1, the upper segment 11A is in the first polarization state. Therefore, when the observer A wears the polarized glasses 200, the first image 301 is visible during the period from after the time difference dt1 until times t1 and t3. Since writing of the second image 302 starts at times t1 and t3, the second image 302 is visible in the vicinity of the upper end 12U from times t0 and t2 until a lapse of time T. Therefore, in this case, the brightness recognized by the observer A is the integral value of the visible period in the curve L2. The integral value of the visible period in the curve L2 is the area S3 indicated by the shaded line in Fig.14 In

[0113] In the example of Fig.13 , the lower segment 11B is shifted from the upper segment 11A by half a frame (T / 2) to switch the polarization state. Therefore, the positional relationship of the second object pixels near the upper end 12U of the display panel 12 with respect to the upper segment 11A is equal to the positional relationship of the second object pixels slightly below the middle of the display panel 12 with respect to the lower segment 11B. Therefore, when the second object pixels are located slightly below the middle of the display panel 12, the brightness viewed by the observer A wearing the polarized glasses 200 also becomes Fig.14 the area S3 of

[0114] When the second object pixels are located near the lower end 12D of the display panel 12 ( Fig.15 ), the first image 301 is written at times that are delayed by the amount of writing time from the times t0 and t2 when writing of the first image starts, that is, after a time T of 1 frame from times t0 and t2 (times t1 and t3), and is displayed until times t2 and t4. After a time difference dt2 (dt2 < T) from time t2, the upper segment 11A is in the first polarization state, and when a time T has elapsed (t2 + dt2 + T), the first polarization state is switched to the second polarization state. Therefore, when the observer A wears the polarized glasses 200, the first image 301 is visible during the period from time t3 until the upper segment 11A ends the first polarization state. Since the second image 302 is written until time t3, the second image 302 is visible from after a time difference dt2 (dt2 < T) from time t2 until time t3. Therefore, in this case, the brightness recognized by the observer A is the integral value of the visible period in the curve L3. The integral value of the visible period in the curve L3 is the area S4 indicated by the shaded line in Fig.15 In

[0115] In Fig.13In the example, the lower segment 11B switches the polarization state by shifting half a frame (T / 2) from the upper segment 11A. Therefore, the positional relationship of the second object pixel located near the lower end 12D 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 middle of the display panel 12 relative to the upper segment 11A. Therefore, when the second object pixel is located slightly above the middle of the display panel 12, the brightness perceived by the observer A wearing the polarized glasses 200 becomes Fig.15 The area is S4.

[0116] By dividing the polarization module 11 into a plurality of segments in the direction D and switching the polarization state in a staggered manner, it is possible to suppress the area of ​​the display panel 12 that is included in the range of the first polarization state in the polarization module 11 and has not been rewritten to the first image 301, compared with the case where the polarization state of the entire polarization module 11 is switched uniformly at the beginning of each frame. Therefore, compared with the case where the polarization state of the entire polarization module 11 is switched uniformly at the beginning of each frame, the difference (unevenness) in the brightness of the first image 301 that is viewed by the observer A wearing the polarization glasses 200 is suppressed. As a result, the observer A can improve the display quality when wearing the polarization glasses 200.

[0117] The offset of the time for switching the polarization state of the upper segment 11A and the lower segment 11B is not limited to 1 / 2 (T / 2) of 1 frame time, and may be other time differences. The offset of the time for 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.

[0118] The control of making the timing of switching the polarization state of the upper segment 11A and the lower segment 11B different may also include the timing of switching the polarization state of the upper segment 11A and the lower segment 11B at the same time, that is, the control of uniformly switching the polarization state of the entire polarization module 11. That is, the AR panel drive unit 15 may also switch the polarization state of the upper segment 11A and the lower segment 11B at the same time. The division of the polarization module 11 in the direction D is not limited to two divisions. The polarization module 11 may also be divided into three or more in the direction D.

[0119] <Third Embodiment> As another example, in which the image generating unit 23 generates the second image data D2 from the first image data D1, the pixel values ​​of pixels belonging to at least a portion of the first image data D1 can be transformed according to the LUT 24, and the pixel values ​​of pixels belonging to an area other than the portion of the first image data D1 can be set as specific grayscale values ​​that are pre-set regardless of the pixel values.

[0120] Fig.16This is a diagram for explaining an example of a method for generating second image data D2 from first image data D1 in the display system 100 of the third embodiment. The image generating unit 23 converts the pixel value of a specific pixel of the first image data D1 into a pixel value specified by the LUT 24. The specific pixel is a pixel belonging to one or more regions 301a, 301b, 301c, and 301d that are predefined in the first image 301. The image generating unit 23 performs black-and-white inversion on each pixel of the regions 301a, 301b, 301c, and 301d, as in the first embodiment.

[0121] In addition, the image generation unit 23 sets the pixels in the area other than the areas 301a, 301b, 301c, and 301d to a predetermined grayscale such as black (grayscale 0). The converted color is not limited to black (grayscale 0), but may be another grayscale. For example, different grayscales may be specified for RGB.

[0122] In the display system 100 according to the first embodiment, since all pixels of the first image data D1 are converted into the second image data D2 having a specific relationship, the pattern of the first image 301 may be represented in the second image 302. Therefore, when the observer A does not wear the polarized glasses 200, the pattern of the first image 301 may be instantly perceived due to the line of sight tracking integral effect due to blinking, sudden line of sight movement, etc.

[0123] In contrast, in the display system 100 of the third embodiment, the area in the second image 304 where the pattern of the first image 301 may be displayed is limited to a part of the area, and is not displayed in other areas. Therefore, even if there is blinking or a sudden movement of the line of sight, the pattern of the first image 301 is difficult to be perceived. As a result, the confidentiality of the first image 301 can be further improved.

[0124] In the display system 100 according to the third embodiment, when the observer A does not wear the polarized glasses 200 , the fourth image 305 in which the first image 301 and the second image 304 are synthesized is perceived. Fig.17 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 third embodiment, and an image perceived by the observer A, and shows an image perceived when the observer A does not wear the polarization glasses 200 .

[0125] exist Fig.17In the embodiment, at time t0-t1 and time t2-t3, the first image 301 is displayed on the display panel 12. In addition, at time t0 and t2, the polarization module 11 is switched to the first polarization state. At time t1 to t2 and at time t3 to t4, the second image 304 is displayed on the display panel 12. In addition, at time t1 and t3, the polarization module 11 is switched to the second polarization state.

[0126] When the observer A does not wear the polarized glasses 200, he perceives the fourth image 305 obtained by synthesizing the first image 301 and the second image 304. The sum of the pixel values ​​of the regions 301a, 301b, 301c, and 301d of the first image 301 and the second image 304 is equal. The region other than the regions 301a, 301b, 301c, and 301d is a monochrome region such as black (0 grayscale) of the pixel value of the second image 304. Therefore, the region other than the regions 301a, 301b, 301c, and 301d of the fourth image 305 is an image including the pattern of the first image 301, but the regions 301a, 301b, 301c, and 301d are, for example, gray images, etc., and the entirety is a specific grayscale. Therefore, when the observer A does not wear the polarized glasses 200, the first image 301 is not perceived. As a result, the confidentiality of the first image 301 can be ensured.

[0127] Regions 301a, 301b, 301c, and 301d may be any region as long as they are of a size and shape that makes it difficult to perceive the pattern of the first image 301 regardless of blinking, sudden eye movement, etc. Preferably, regions 301a, 301b, 301c, and 301d are smaller than the first image 301 and their positions are discontinuous. Fig.16 In the example of , in the first image 301, the regions 301a, 301b, 301c, and 301d are arranged on a staggered grid. As a result, when the observer A does not wear the polarized glasses 200, the pattern of the first image 301 is more difficult to perceive. In addition, the region where the pixel value is converted is smaller than the first image 301 as a whole, so the amount of calculation in the image generation unit 23 is suppressed.

[0128] The sizes of the regions 301a, 301b, 301c, and 301d are not necessarily fixed (the same). As another example, the sizes of the regions 301a, 301b, 301c, and 301d may be determined based on the content included in the first image 301. For 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 font size based on the information included in the image signal Sg1, and determine the sizes of the regions 301a, 301b, 301c, and 301d based on the correspondence between the font size and the size of the region stored in advance.

[0129] <Fourth Embodiment> As another example, the image generating unit 23 may generate the second image data D2 from the first image data D1 by dividing the first image 301 into a plurality of regions, and changing the pixel values ​​of each region to a predetermined pixel value according to the pixel values ​​belonging to each region. In this case, the LUT 24 specifies the correspondence of the pixel values ​​for the pixel values ​​of the pixels belonging to the region. As an example, the pixel values ​​of the pixels belonging to the region may also be the range of the grayscale of each region, that is, the minimum and maximum values ​​of the grayscale. As another example, other characteristics such as the average value of the grayscale may also be used.

[0130] Fig.18 24 is a diagram showing another example of the LUT 24. The LUT 24 of the fourth embodiment defines a plurality of data groups 243, 244, and 245 of pixel values ​​of the second image data D2 corresponding to the pixel value 241 of the first image data D1. Specifically, the LUT 24 of the fourth embodiment defines a plurality of data groups 243, 244, and 245 of pixel values ​​of the second image data D2 corresponding to the pixel value 241 of the first image data D1. A data group (data group A) 243 of pixel values ​​127, ..., 0 of the second image corresponding to each pixel value within the range of A data group (data group B) 244 of pixel values ​​255, ..., 0 of the second image corresponding to each pixel value within the range of A data group (data group C) 245 of pixel values ​​255, ..., 64 of the second image corresponding to each pixel value within the range of .

[0131] The method of 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.18 As another example, it may be a plurality of tables prepared for each range of pixel values ​​of the first image data D1, or it may be a plurality of calculation expressions. In addition, LUT24 may separately 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 color pixel of R, G, and B, or it may jointly 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 color pixel of R, G, and B.

[0132] The plurality of regions may be two or more. As an example, the image generation unit 23 divides the first image 301 into predetermined regions such as 10 pixels × 10 pixels. The size of the region is not limited to a specific size, and may be determined according to predetermined conditions. The image generation unit 23 determines a data set of pixel values ​​of the second image of each region by calculating the maximum value and the minimum value of the pixel value of each region. The image generation unit 23 transforms the pixel values ​​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, thereby generating the second image data D2.

[0133] use Fig.18 In the case of LUT24, the minimum and maximum values ​​of the pixel values ​​are For an area where the minimum and maximum pixel values ​​are 64 to 255, the image generation unit 23 can select either the data set A or the data set B. Similarly, for an area where the minimum and maximum pixel values ​​are 64 to 255, the image generation unit 23 can select either the data set B or the data set C. In such a case, the image generation unit 23 can select a predetermined data set, randomly select, or select according to a specific user operation.

[0134] Preferably, a data set having a small difference between the pixel values ​​of the first image data D1 and the second image data D2 is selected. This can suppress the influence of crosstalk caused by the response and make it easier for the observer A to visually recognize the first image 301 when wearing the polarized glasses 200.

[0135] In the display system 100 according to the fourth embodiment, a data set of pixel values ​​of the second image that is different for each region of the first image 301 can be used. By generating the second image data D2 in this way, the grayscale of each region may be different in the composite image of the first image 301 and the second image perceived by the observer A when the observer A does not wear the polarized glasses 200. That is, by generating the second image data D2 in this way, when the observer A does not wear the polarized glasses 200, the third image including a plurality of grayscales can be perceived.

[0136] <3. Notes> The present invention is not limited to the above-described embodiment, and various modifications are possible. Description of Reference Numerals

[0137] 10: display device, 11: polarization module, 12: display panel, 20: controller, 30: display, 100: display system, 200: polarization glasses, D1: first image data (image data), D2: second image data

Claims

1. A display device, characterized in that: include: monitor; A polarization module, arranged in an overlapping manner on the display, capable of actively switching the polarization state between a first polarization state and a second polarization state; as well as and a controller, The controller is constructed as follows: generating second image data based on the first image data, displaying a first image based on the first image data and a second image based on the second image data on the display in a time-division manner, The polarization state of the polarization module is switched 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.

2. The display device according to claim 1, characterized in that The first polarization state enables the observer to see the first image through polarized glasses worn by the observer. The second polarization state prevents the observer from visually recognizing the second image through the polarized glasses.

3. The display device according to claim 1, characterized in that Generating the second image data includes: converting the grayscale of the image data into a grayscale of a predetermined relationship.

4. The display device according to claim 1, characterized in that Generating the second image data includes: converting the grayscale of pixels belonging to at least a portion of the image data into a grayscale with a different predetermined relationship according to the grayscale, and setting the grayscale of pixels belonging to an area other than the portion of the image data to a specific grayscale that is predetermined independently of the grayscale.

5. The display device according to claim 1, characterized in that Generating the second image data includes: dividing the image data into a plurality of regions, and changing the grayscale of each region to a predetermined relationship according to the grayscale of pixels belonging to each of the regions.

6. The display device according to claim 1, characterized in that: Switching the polarization state of the polarization module includes: dividing the polarization module into a plurality of segments along a scanning direction of the display, so that the polarization states of the plurality of segments are switched with a time difference in a sequence along the scanning direction.

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