Display device and control method for display device

Abstract

To suppress crosstalk when a plurality of images is displayed with light of different wavelength bands.SOLUTION: A display device includes a plurality of display elements, a first light source, a second light source, a signal synthesizer that generates a mixed image signal, a pixel control unit that controls an applied voltage of the display element on the basis of the mixed image signal, and a light source control unit that controls the first and second light sources. During a period in which second illumination light is radiated, the pixel control unit controls the applied voltage of some of the display elements among the plurality of display elements according to a signal value of an input signal, and regardless of the signal value of the input signal, the applied voltage of some of the other display elements from among the plurality of display elements is set to a constant value.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a display device and a method for controlling the display device. [Background technology]

[0002] In flight training for airplanes and helicopters, not only actual flight training but also training using a training simulator system that can reproduce various situations is effective. In particular, in night flights of helicopters and the like, one of the main pilot and the co-pilot may fly with the naked eye, while the other pilot wears night vision goggles. For this reason, a simulator system has been developed in which a visible light image and an infrared light image are displayed on a screen, and a pilot with the naked eye and a pilot wearing night vision goggles can train at the same time. Patent Document 1 describes a projector that projects both visible light images and infrared light images on the same display device. Patent Document 1 describes that a video signal for visible light images and a video signal for infrared light images are output in sequence in a frame sequential manner, that is, in a time-division manner. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-524662 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a video signal for a visible light image and a video signal for an infrared light image are output in sequence, so-called crosstalk may occur. For example, even after switching from outputting a video signal for an infrared light image to outputting a video signal for a visible light image, an afterimage caused by the video signal for an infrared light image remains and is visually recognized as crosstalk. Therefore, when displaying multiple images using light of different wavelength bands, such as a visible light image and an infrared light image, it is necessary to suppress crosstalk.

[0005] In view of the above-mentioned problems, an object of the present invention is to provide a display device and a method for controlling the display device that are capable of suppressing crosstalk when displaying a plurality of images using light of different wavelength bands. [Means for solving the problem]

[0006] A display device according to one aspect of the present invention includes a plurality of display elements, a first light source that irradiates a first illumination light which is light in a first wavelength band, a second light source that irradiates a second illumination light which is light in a second wavelength band, a signal synthesis unit that generates a mixed image signal based on an input signal in which frames of a first image signal for displaying an image based on the first illumination light and frames of a second image signal for displaying an image based on the second illumination light are alternately repeated, a pixel control unit that controls an application voltage to the display elements based on the mixed image signal, and a light source control unit that controls the first light source and the second light source, wherein during a period in which the second illumination light is irradiated, the pixel control unit controls an application voltage to some of the display elements in accordance with a signal value of the input signal, while keeping the application voltage to the other display elements of the plurality of display elements at a constant value regardless of the signal value of the input signal.

[0007] A control method for a display device according to one aspect of the present invention is a control method for a display device including a display element, a first light source that irradiates a first illumination light that is light in a first wavelength band, and a second light source that irradiates a second illumination light that is light in a second wavelength band, the control method including: a signal combining step of generating a mixed image signal based on an input signal, in which frames of a first image signal for displaying an image based on the first illumination light and frames of a second image signal for displaying an image based on the second illumination light are alternately repeated; a pixel control step of controlling an applied voltage to the display element based on the mixed image signal; and a light source control step of controlling the first light source and the second light source, wherein in the pixel control step, during a period in which the second illumination light is irradiated, a voltage applied to some of the display elements among the plurality of display elements is controlled in accordance with a signal value of the input signal, while a voltage applied to other of the plurality of display elements is kept constant regardless of the signal value of the input signal. Effect of the Invention

[0008] According to the present invention, crosstalk can be suppressed when a plurality of images are displayed using light of different wavelength bands. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a display device according to the present embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of the polarization conversion element according to this embodiment. [Diagram 3] FIG. 3 is a schematic block diagram of a control unit according to the present embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a signal. [Diagram 5] FIG. 5 is a diagram showing an example of the drive gradation table. [Figure 6] FIG. 6 is a schematic diagram illustrating an image display according to a comparative example. [Figure 7] FIG. 7 is a schematic diagram illustrating the display of an image according to this embodiment. [Figure 8]FIG. 8 is a schematic diagram illustrating an image display according to another example of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

[0011] (Display Device Configuration) Fig. 1 is a schematic diagram of a display device according to the present embodiment. As shown in Fig. 1, the display device 100 according to the present embodiment includes a display mechanism 10 and a control unit 12. The display device 100 is a display device that displays a visible light image, which is an image based on visible light, and an infrared light image, which is an image based on infrared light. The display mechanism 10 includes a first light source 101, a second light source 102, a phosphor 103, polarizing plates 105R, 105G, and 105B, a first display element 106R, a second display element 106G, a third display element 106B, polarizing plates 107R, 107G, and 107B, a color synthesis prism 108, a projection lens 109, dichroic mirrors 120 to 123, reflecting mirrors 130 to 132, lenses 140 to 148, and a polarization conversion element 150. When there is no need to distinguish between the first display element 106R, the second display element 106G, and the third display element 106B, they will be referred to as display elements 106.

[0012] The dichroic mirrors 120 to 123 have the property of separating incident light by reflection and transmission, with the separation wavelength as the separation boundary. The dichroic mirrors 120 to 123 can be fabricated by forming, for example, a dielectric multilayer film on a predetermined region of a transparent material such as a glass plate or a prism. The optical properties can be set according to the material and film thickness of the dielectric material constituting the dielectric multilayer film.

[0013] The first light source 101 emits a first illumination light, which is light in a first wavelength band. In this embodiment, the first wavelength band is a wavelength band of visible light, and the first illumination light is visible light. More specifically, the first light source 101 according to this embodiment is, for example, a blue laser light source composed of a blue laser element. Note that the blue illumination light is, for example, light in a wavelength band of 450 nm or more and 495 nm or more. The first light source 101 emits blue illumination light, which is blue laser light, as the first illumination light. The blue illumination light is irradiated onto the dichroic mirror 120. The dichroic mirror 120 has a characteristic of reflecting the blue illumination light and transmitting the yellow illumination light.

[0014] The blue illumination light emitted from the first light source 101 is reflected by the dichroic mirror 120 and is then collected by the lens 140 and applied to the phosphor 103 .

[0015] Phosphor 103 has a fluorescent layer and a reflective surface. The fluorescent layer generates yellow illumination light containing a red band component and a green band component, the intensity of which corresponds to the energy intensity of the blue illumination light emitted from first light source 101. The reflective surface reflects the blue illumination light transmitted through the fluorescent layer and the yellow illumination light generated by the fluorescent layer.

[0016] Yellow illumination light, which is fluorescence generated by phosphor 103, is irradiated in the direction of dichroic mirror 120 via lens 140. The yellow illumination light passes through dichroic mirror 120 and is irradiated onto dichroic mirror 121.

[0017] The blue illumination light reflected by phosphor 103 is irradiated in the direction of dichroic mirror 120 via lens 140. The surface area of ​​dichroic mirror 120 is set to be slightly larger than the luminous flux of the blue laser light irradiated from first light source 101. On the other hand, since the blue illumination light reflected by phosphor 103 is diffused upon reflection, the luminous flux of the blue illumination light irradiated from lens 140 to dichroic mirror 120 spreads out sufficiently larger than the area of ​​dichroic mirror 120. In other words, the blue illumination light irradiated from lens 140 to dichroic mirror 120 is partially reflected by dichroic mirror 120, but the majority is irradiated to dichroic mirror 121.

[0018] The second light source 102 emits second illumination light, which is light in a second wavelength band different from the first wavelength band. In this embodiment, the second wavelength band is an infrared wavelength band, and the second illumination light is infrared light. More specifically, the second light source 102 according to this embodiment is, for example, an infrared LED light source composed of a near-infrared LED element. The second light source 102 emits infrared LED light. Hereinafter, the infrared LED light is referred to as infrared illumination light. Note that the infrared illumination light is, for example, light in a wavelength band of 0.7 μm to 1000 μm. The infrared illumination light is irradiated onto the dichroic mirror 121 via lenses 141 and 142. The dichroic mirror 121 has a characteristic of reflecting the infrared illumination light and transmitting the yellow illumination light and the blue illumination light.

[0019] The blue illumination light and yellow illumination light transmitted through dichroic mirror 121 , and the infrared illumination light reflected by dichroic mirror 121 are further reflected by reflecting mirror 130 , and enter lens 143 .

[0020] The lenses 143 and 144 are, for example, fly-eye lenses. The blue illumination light, yellow illumination light, and infrared illumination light reflected by the reflecting mirror 130 are uniformly distributed by the lenses 143 and 144 and then enter the polarization conversion element 150.

[0021] Fig. 2 is a diagram showing an example of the configuration of a polarization conversion element according to this embodiment. As shown in Fig. 2, polarization conversion element 150 has a polarization beam splitter 151 and a retardation plate 152. Polarization beam splitter 151 reflects either s-polarized light or p-polarized light and transmits the other. Fig. 2 shows a state in which polarization beam splitter 151 reflects s-polarized light and transmits p-polarized light.

[0022] The retardation plate 152 converts either s-polarized light or p-polarized light into the other. Fig. 2 shows the retardation plate 152 converting s-polarized light into p-polarized light. The retardation plate 152 is, for example, a λ / 2 retardation plate. The polarization conversion element 150 converts each illumination light into p-polarized light.

[0023] 1, each illumination light converted into p-polarized light by the polarization conversion element 150 is irradiated onto the dichroic mirror 122 via the lens 145. The lens 145 is, for example, a condenser lens.

[0024] The dichroic mirror 122 separates the incident blue illumination light BL from the yellow illumination light YL and the infrared illumination light IRL. The yellow illumination light YL and the infrared illumination light IRL separated by the dichroic mirror 122 are reflected by the reflecting mirror 131 and enter the dichroic mirror 123.

[0025] The dichroic mirror 123 separates the incident yellow illumination light YL and infrared illumination light IRL into red illumination light RL and infrared illumination light IRL containing a red band component, and green illumination light GL containing a green band component, using a wavelength between the red light band and the green light band as a separation boundary. Specifically, the dichroic mirror 123 reflects the green band component of the incident yellow illumination light YL to emit green illumination light GL, and transmits the red band component of the incident yellow illumination light YL to emit red illumination light RL. The dichroic mirror 123 also transmits the infrared illumination light IRL. The red illumination light RL is, for example, light in a wavelength band of 620 nm to 750 nm, and the green illumination light GL is, for example, light in a wavelength band of 495 nm to 570 nm.

[0026] The red illumination light RL and the infrared illumination light IRL separated by the dichroic mirror 123 are irradiated onto the polarizing plate 105R via a lens 146. The green illumination light GL separated by the dichroic mirror 123 is irradiated onto the polarizing plate 105G via a lens 147. The blue illumination light BL separated by the dichroic mirror 122 is reflected by the reflecting mirror 132 and irradiated onto the polarizing plate 105B via a lens 148.

[0027] The polarizing plates 105R, 105G, and 105B have the property of reflecting either s-polarized light or p-polarized light and transmitting the other. Fig. 1 shows a state in which the polarizing plates 105R, 105G, and 105B reflect s-polarized light and transmit p-polarized light. The polarizing plates 105R, 105G, and 105B are also called reflective polarizing plates. The polarizing plates 105R, 105G, and 105B are, for example, wire grid polarizing plates.

[0028] The red illumination light RL and the infrared illumination light IRL, which are p-polarized light, are transmitted through the polarizing plate 105R and are irradiated onto the first display element 106R. The green illumination light GL, which is p-polarized light, is transmitted through the polarizing plate 105G and is irradiated onto the second display element 106G. The blue illumination light BL, which is p-polarized light, is transmitted through the polarizing plate 105B and is irradiated onto the third display element 106B. In this way, the infrared illumination light IRL from the second light source 102 is irradiated onto the same first display element 106R as the illumination light based on the illumination light from the first light source 101 (here, the red illumination light RL).

[0029] The first display element 106R, the second display element 106G, and the third display element 106B are, for example, reflective liquid crystal display elements. In this embodiment, the first display element 106R, the second display element 106G, and the third display element 106B are reflective liquid crystal display elements, but they are not limited to reflective types and may be configured to use transmissive liquid crystal display elements. In addition, various applications are possible for configurations that use other display elements instead of liquid crystal display elements.

[0030] The first display element 106R optically modulates the p-polarized red illumination light RL based on image data of the red component to generate s-polarized red image light RM. The first display element 106R also optically modulates the p-polarized infrared illumination light IRL based on image data of the infrared light component to generate s-polarized infrared image light IRM. The red image light RM and the infrared image light IRM are also collectively referred to as the first image light RM / IRM.

[0031] The second display element 106G optically modulates the p-polarized green illumination light GL based on image data of the green component to generate s-polarized green image light GM. The third display element 106B optically modulates the p-polarized blue illumination light BL based on image data of the blue component to generate s-polarized blue image light BM. That is, the first display element 106R functions as a red image light modulation element and an infrared image light modulation element, the second display element 106G functions as a green image light modulation element, and the third display element 106B functions as a blue image light modulation element.

[0032] The polarizing plates 107R, 107G, and 107B have the property of transmitting either s-polarized light or p-polarized light and reflecting or absorbing the other. Fig. 1 shows a state in which the polarizing plates 107R, 107G, and 107B transmit s-polarized light and absorb unnecessary p-polarized light. The polarizing plates 107R, 107G, and 107B are also called transmissive polarizing plates.

[0033] In displaying an infrared light image, it is required to irradiate the infrared image light with high illuminance. Therefore, optical components on the optical path of the infrared illumination light IRL or the infrared image light IRM are more likely to generate heat than optical components on the optical path of illumination light or image light of other colors. For this reason, a wire grid polarizer that has high heat resistance and good characteristics over a wide band is used for the polarizer 107R that is the optical path of the infrared image light IRM. This makes it possible to improve reliability and performance compared to the case where a general resin polarizer is used. On the other hand, since the wire grid polarizer is expensive compared to a general resin polarizer, a general resin polarizer may be used for the polarizers 107G and 107B that are not on the optical path of the infrared image light IRM.

[0034] Red image light RM and infrared image light IRM, which are s-polarized light and generated by first display element 106R, are reflected by polarizing plate 105R, transmitted through polarizing plate 107R, and irradiated onto color synthesis prism 108. Green image light GM, which is s-polarized light and generated by second display element 106G, is reflected by polarizing plate 105G, transmitted through polarizing plate 107G, and irradiated onto color synthesis prism 108. Blue image light BM, which is s-polarized light and generated by third display element 106B, is reflected by polarizing plate 105B, transmitted through polarizing plate 107B, and irradiated onto color synthesis prism 108.

[0035] The color synthesis prism 108 reflects the red image light RM, the infrared image light IRM, and the blue image light BM, transmits the green image light GM, and irradiates each image light onto a projection lens 109.

[0036] The red image light RM, the infrared image light IRM, the green image light GM, and the blue image light BM are projected onto a screen (not shown) or the like via a projection lens 109. A visible light image is displayed by the red image light RM, the green image light GM, and the blue image light BM. An infrared light image is displayed by the infrared image light IRM.

[0037] The display mechanism 10 has the above-described configuration. However, the configuration of the display mechanism 10 is not limited to the above description, and may have any configuration. For example, the first light source 101 is not limited to irradiating blue illumination light as the first illumination light, and may irradiate visible light, and may irradiate light of a different wavelength band from the second light source 102. Furthermore, the second light source 102 is not limited to irradiating infrared illumination light as the second illumination light. Furthermore, the display mechanism 10 of the present embodiment is a projector that projects an image onto a screen provided separately from the display device 100, but is not limited thereto, and may be, for example, a device that displays an image on a display integrated with the display device 100.

[0038] FIG. 3 is a schematic block diagram of the control unit according to this embodiment. FIG. 4 is a diagram showing an example of a signal. The control unit 12 controls the display mechanism 10 to display a visible light image and an infrared light image. As shown in FIG. 3, the control unit 12 includes a signal synthesis unit 20, a signal processing unit 22, a light source control unit 24, a subframe data generation unit 26, and a pixel control unit 28. The signal synthesis unit 20, the signal processing unit 22, the light source control unit 24, the subframe data generation unit 26, and the pixel control unit 28 may be configured as an integrated circuit, which is hardware, or may be configured as a central processing unit (CPU) which is a computing device of a computer, and a memory, and may be configured to perform the processing described below by causing the CPU to execute a computer program (software) stored in the memory. In this embodiment, the pixel control unit 28 is a pixel circuit that drives the display element 106.

[0039] The signal synthesis unit 20 synthesizes the first image signal S V and the second image signal S I The first image signal S V is an input signal for displaying an image using light based on the first illumination light, and in this embodiment, is an input signal for displaying a visible light image. V The second image signal S I is an input signal for displaying an image using light based on the second illumination light, and in this embodiment, is an input signal for displaying an infrared light image. I The visible light image and the infrared light image are generated by the first display element 106R, the second display element 106G, and the third display element 106B, so the first image signal S V and the second image signal S I The signal synthesis unit 20 includes information about the voltages applied to the first display element 106R, the second display element 106G, and the third display element 106B. V and the second image signal S Imay be input, or information on an image captured by the camera may be input as a first image signal S V and the second image signal S I That is, the first image signal S V and the second image signal S I The method of inputting is arbitrary.

[0040] First image signal S V and the second image signal S I is a signal that is divided into periods of processing length, i.e., frame rates, and an intensity is assigned to each frame rate. In FIG. 4, the first image signal S V and the second image signal S I The figure shows an example in which both frame rates are 60 Hz.

[0041] The signal synthesis unit 20 synthesizes the input first image signal S V and the second image signal S I and combine them to produce a mixed image signal S F A mixed image signal S F is the first image signal S V and the second image signal S I That is, the first image signal S V and the second image signal S I The first image signal S is a signal in which one frame's worth of a first image signal S is alternately repeated, and can also be called a frame sequential signal. V and the second image signal S I The frame rate (display speed) of the first image signal S is converted to a predetermined multiple. V and the second image signal S I The mixed image signal S F That is, the mixed image signal S F is the first image signal S V and the second image signal S I The first image signal S V and the second image signal S I The mixed image signal S FIn FIG. 4, the signal synthesis unit 20 synthesizes a first image signal S V and the second image signal S I and are converted by a factor of two to obtain the first image signal S V and the second image signal S I A mixed image signal S with a frame rate of 120 Hz is generated so that F Here is an example of generating

[0042] In FIG. 4, the first image signal S V and the second image signal S I The first image signal S V and the second image signal S I The frequency is not limited to 60 Hz, but may be other frequencies (for example, 50 Hz, 24 Hz, etc.). The signal synthesis unit 20 converts these signals into signals with double the frequency, but the frequency conversion is not limited to double and may be more than that. It may also be 1x (same frequency).

[0043] In addition, the display time of the visible light image and the infrared light image, i.e., the mixed image signal S F A first image signal S included in V The frame length of the second image signal S I The frame lengths do not have to be the same. For example, within a 60 Hz period, a visible light image may be displayed for 1 / 3 of the period, and an infrared light image may be displayed for 2 / 3 of the period. Since the gradation of an infrared light image is expected to be higher than that of a visible light image, the light intensity of the infrared light image can be kept strong by lengthening the display period of the infrared light image.

[0044] The signal processing unit 22 shown in FIG. F The signal processor 22 generates image data D0 with N gradations (N is a natural number) by performing calculations between neighboring pixels or between frames. V and the second image signal S IFor each of the frames, the signal processing unit 22 generates first image data D0R for the first display element 106R, second image data D0G for the second display element 106G, and third image data D0B for the third display element 106B as image data. The signal processing unit 22 outputs the generated image data D0 to the subframe data generating unit 26. The subframe data generating unit 26 converts the N gradation image data D0 into subframe data D1 consisting of 1s and 0s based on a drive gradation table. The subframe data D1 is data that indicates the on / off state of the voltage applied to the display element 106 within a frame. The signal processing unit 22 generates first sub-frame data D1R indicating the on / off state of the applied voltage to the first display element 106R from the first image data D0R, generates second sub-frame data D1G indicating the on / off state of the applied voltage to the second display element 106G from the second image data D0G, and generates third sub-frame data D1B indicating the on / off state of the applied voltage to the third display element 106B from the third image data D0B.

[0045] FIG. 5 is a diagram showing an example of the drive gradation table. In this embodiment, the subframe data generating unit 26 divides one frame into N subframes, and performs gradation display by switching on and off each subframe. The subframes are named SF1, SF2, . . . SFN in order from the most recent subframe. The vertical columns of the drive gradation table shown in FIG. 5 indicate gradations, and the subframe data D1 is generated based on the values ​​of the drive gradation table corresponding to the gradations of the image data. In this embodiment, the case of N=12 is described as an example. The value of N is not limited to 12 and can be set to various values. For example, the value of N may be 32 or 64. The drive gradation table of this embodiment is a table in which the subframes that are 1 extend from the later subframes in time to the earlier subframes in time as the gradation becomes higher. That is, the subframe data D1 is generated so that the number of subframes that are 1 increases from the last subframe to the earlier subframes in time as the gradation of the image data becomes higher in one frame. However, the subframe data generator 26 is not limited to generating the subframe data D1 in this manner. For example, the subframe data generator 26 may generate the subframe data D1 such that the number of subframes that are 1 increases from the first subframe to later subframes as the grayscale of the image data becomes higher.

[0046] The subframe data generating unit 26 controls the pixel control unit 28 based on the generated subframe data D1. The pixel control unit 28 drives the display element 106 based on the subframe data D1. Specifically, the pixel control unit 28 controls the voltage applied to the display element 106 based on the subframe data D1. For example, a 1 in the subframe data D1 corresponds to turning on the voltage applied to the display element 106, and a 0 in the subframe data D1 corresponds to turning off the voltage applied to the display element 106. That is, the pixel control unit 28 turns on the voltage applied to the display element 106 during a period in which 1 continues in the subframe data D1 in one frame. Then, the pixel control unit 28 turns off the voltage applied to the display element 106 during a period in which 0 continues in the subframe data D1 in one frame. The pixel control unit 28 controls the voltage applied to the first display element 106R based on the first subframe data D1R, controls the voltage applied to the second display element 106G based on the second subframe data D1G, and controls the voltage applied to the third display element 106B based on the third subframe data D1B. F Since the mixed image signal S is generated from the image data D0 based on F It can be said that the voltage applied to the display element 106 is controlled based on the above.

[0047] The signal processor 22 outputs the mixed image signal S F The first light source control signal S LV , the second light source control signal S LI The light source control unit 24 generates the first light source control signal S LV , the second light source control signal S LI In more detail, the first light source control signal S LV is a signal for controlling the first light source 101. The light source control unit 24 outputs the first light source control signal S LV Based on the second light source control signal S LIis a signal for controlling the second light source 102. The light source control unit 24 outputs the second light source control signal S LI Based on the first light source control signal S, the second light source 102 is switched on and off to emit the second illumination light. LV and the second light source control signal S LI The period of the mixed image signal S F The period of the first light source control signal S LV is the mixed image signal S F The first image signal S V During the frame period, the irradiation of the first illumination light is turned on, and the second image signal S I During the period of the frame, the irradiation of the first illumination light is turned off. LI is the mixed image signal S F The first image signal S V During the frame period, the irradiation of the second illumination light is turned off, and the second image signal S I In this embodiment, the first light source control signal S is used to control the first light source 101 and the second light source 102. LV and the second light source control signal S LI The mixed image signal S F Alternatively, the first light source 101 and the second light source 102 may be controlled by a single signal synchronized with the above.

[0048] 1, the first illumination light from the first light source 101 is irradiated as infrared illumination light IRL, green illumination light GL, and color illumination light BL to the first display element 106R, the second display element 106G, and the third display element 106B, respectively, while the second illumination light from the second light source 102 is irradiated as infrared illumination light IRL only to the first display element 106R. Therefore, it can be said that the light source control unit 24 causes the first light source 101 to irradiate the first display element 106R, the second display element 106G, and the third display element 106B with the first illumination light, while causing the second light source 102 to irradiate the second illumination light only to the first display element 106R among the first display element 106R, the second display element 106G, and the third display element 106B.

[0049] Here, the pixel control unit 28 according to the present embodiment receives the first image signal S V In the frame, i.e., in the period in which a visible light image is displayed, the first image signal S V On the other hand, the pixel control unit 28 controls the applied voltages to the first display element 106R, the second display element 106G, and the third display element 106B based on the second image signal S I In the frame, i.e., in the period in which the infrared light image is displayed, the second image signal S I While controlling the voltage applied to the first display element 106R based on the second image signal S I Regardless of this, the voltage applied to the second display element 106G and the third display element 106B is kept constant (off in this embodiment). Specific explanations will be given below.

[0050] (Comparative Example) 6 is a schematic diagram for explaining the display of an image according to a comparative example. As shown in FIG. 6, in the following example, the first light source control signal S LV and the second light source control signal S LI The first light source control signal S is switched between 0 and 1, that is, the first illumination light and the second illumination light are switched on and off every period T, with the period T being from time t1 to time t3. LV is 0, that is, the light source control unit 24 turns off the irradiation of the first illumination light (visible light) by the first light source 101, and the second light source control signal S LI is 1, that is, the light source control unit 24 turns on the emission of the second illumination light (infrared light) by the second light source 102. Then, during the period from time t2 to time t3 (time t1 of the next cycle T), the first light source control signal S LV is 1, that is, the light source control unit 24 turns on the irradiation of the first illumination light (visible light) by the first light source 101, and the second light source control signal S LI is 0, that is, the light source control unit 24 turns off the emission of the second illumination light (infrared light) by the second light source 102. Note that when switching between the emission of the first illumination light and the second illumination light, a blank period during which neither the first illumination light nor the second illumination light is emitted may be provided.

[0051] Subframe data and the first light source control signal S LV and the second light source control signal S LI That is, the subframe data is synchronized in phase with the second light source control signal S LI The period from time t1 to time t2 during which the second image signal S is on is a period during which the second image signal S is used to display an infrared image. i The first light source control signal S LV The period from time t2 to time t3 (time t1 of the next period T) during which the first image signal S is turned on is a period during which the first image signal S is turned on. V is assigned as a frame.

[0052] In this example, the first image signal S V The first image signal S includes information (signal value) to turn on all of the applied voltages to the first display element 106R, the second display element 106G, and the third display element 106B. V In the frame, the first image data D0Rx for the first display element 106R, the second image data D0Gx for the second display element 106G, and the third image data D0Bx for the third display element 106B are included in the first image signal S V 6, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx for the third display element 106B each have a gradation of 1 or more depending on the signal value of each of the first and second subframe data D1Rx, D1Gx, and D1Bx. Therefore, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx each have a period during which they are 1. In the example of FIG. 6, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx are 1 from time t2a to time t3.

[0053] In this example, the second image signal S I The second image signal S also includes information to turn on all of the applied voltages to the first display element 106R, the second display element 106G, and the third display element 106B. I In the frame, the second light source control signal S LI Since the subframe data is generated according to the signal value of the second image signal S IIn the frame, the first image data D0Rx, the second image data D0Gx, and the third image data D0Bx are included in the second image signal S I Depending on the signal value of each of the second image signals S, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx each include a period during which the data is 1. In the example of FIG. 6, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx are all 1 from time t1a to time t2. Note that in the example of FIG. 6, the first subframe data D1Rx, the second subframe data D1Gx, and the third subframe data D1Bx are all 1. I The length of the period during which the subframe data is 1 in the frame (from time t1a to time t2) is L However, this is only an example, and the length of each period is longer than the length of the period (from time t2a to time t3) in which the subframe data is 1 in the first image signal S V and the second image signal S I It depends on.

[0054] Here, the intensity of the output light output from the display device 100, that is, the intensity of the light of the visible light image or the infrared light image, when the display element 106 is constantly irradiated with illumination light from a light source while driving the display element 106 with a predetermined subframe data, is defined as the output light response degree. That is, the higher the output light response degree, the higher the intensity of the output light. However, since the output light response degree refers to the intensity of the output light when it is assumed that the display element 106 is always irradiated with illumination light, when the illumination light is not actually irradiated, even if the output light response degree is higher than zero, the actual intensity of the output light is zero. That is, the output light response degree can be said to indicate the degree of orientation of the liquid crystal of the display element 106 when the display element 106 is driven with the subframe data. In this case, the higher the output light response degree, the closer the orientation of the liquid crystal of the display element 106 is to the orientation in a state in which a voltage is applied. Hereinafter, the orientation in a state in which a voltage is applied is described as a display orientation, and the orientation in a state in which a voltage is not applied is described as a non-display orientation.

[0055] When a voltage is applied to the display element 106, that is, when the subframe data is switched to 1, the orientation of the liquid crystal of the display element 106 is switched from the non-display orientation to the display orientation, and the output light response degree increases. In this case, the liquid crystal is gradually switched from the non-display orientation to the display orientation, that is, the orientation change of the liquid crystal is delayed with respect to the voltage, so the output light response degree gradually increases from the timing when the subframe data is switched to 1, and becomes a constant value when the display orientation is reached. Also, when the voltage application to the display element 106 is stopped, that is, when the subframe data is switched to 0, the orientation of the liquid crystal of the display element 106 is switched from the display orientation to the non-display orientation, and the output light response degree decreases. In this case, the liquid crystal is gradually switched from the display orientation to the non-display orientation, so the output light response degree gradually decreases from the timing when the subframe data is switched to 0, and becomes a constant value when the non-display orientation is reached.

[0056] In the example of FIG. 6, the output photoresponse degree Ax gradually increases and then remains constant from time t1a when the subframe data D1x is switched to 1, and gradually decreases and then remains constant at zero from time t2 when the subframe data D1x is switched to 0. This behavior of the output photoresponse degree Ax is expressed by the second image signal S Ix This behavior corresponds to the gradation of an infrared light image. After that, the output photoresponse degree Ax gradually increases from time t2a when the subframe data D1x is switched to 1, and then remains constant. Then, from time t3 when the subframe data D1x is switched to 0 (time t1 of the next period T), the output photoresponse degree Ax gradually decreases and then remains constant. This behavior of the output photoresponse degree Ax is the first image signal S VxThis corresponds to the behavior of the output light response degree Ax from time t1 to time t2, that is, the gradation of the visible light image. Here, the second illumination light (infrared light) is irradiated from time t1 to time t2. Therefore, from time t1a to time t2, an infrared light image based on the second illumination light (infrared light) corresponding to the output light response degree Ax from time t1a to time t2 is displayed. Also, the first illumination light (visible light) is irradiated from time t2 to time t3. Therefore, from time t2a to time t3 when the output light response degree Ax starts to rise again, a visible light image based on the first illumination light (visible light) corresponding to the output light response degree Ax from time t2a to time t3 is displayed. However, due to the delay in the alignment change of the liquid crystal relative to the voltage, the output light response degree Ax does not become zero and remains, for example, even in the period between time t2 and time t2a. Therefore, in the period between time t2 and time t2a when it is not actually desired to display a visible light image, a visible light image corresponding to the remaining output light response degree Ax is displayed (the portion indicated by the dashed circle in FIG. 6). Ix Since this corresponds to the behavior of the infrared light image, that is, the gradation for the infrared light image, the image for the infrared light image ends up being displayed as a visible light image in the period between time t2 and time t2a, and therefore the visible light image in the period between time t2 and time t2a is perceived as crosstalk by a viewer of the visible light image.

[0057] (Present embodiment) 7 is a schematic diagram for explaining the display of an image according to the present embodiment. In this embodiment, the second image signal S I In the frame, the second image signal S I Regardless of the signal value, the voltage applied to the second display element 106G and the third display element 106B is kept at a constant value (0 in this example), thereby suppressing crosstalk.

[0058] The example of FIG. 7 also uses the first image signal S V and the second image signal S I That is, the first image signal S VThe first image signal S includes information to turn on all of the voltages applied to the first display element 106R, the second display element 106G, and the third display element 106B. V In the frame, the first image data D0R, the second image data D0G, and the third image data D0B are converted into a first image signal S V The subframe data generator 26 generates the first subframe data D1R, the second subframe data D1G, and the third subframe data D1B so that each of them has a gradation of 1 or more depending on the signal value of the first image signal S. Therefore, in this embodiment as well, the first subframe data D1R, the second subframe data D1G, and the third subframe data D1B are 1 between time t2a and time t3, and the pixel controller 28 turns on the voltages applied to the first display element 106R, the second display element 106G, and the third display element 106B between time t2a and time t3. In this way, the first image signal S V In the frame, the pixel control unit 28 outputs the first image signal S V The control circuit 106 controls the voltages applied to the first display element 106R, the second display element 106G, and the third display element 106B in accordance with the signal value.

[0059] In this embodiment, the second image signal S I In the frame, the second image signal S I Regardless of the signal value of the second image signal S, the gradation of the second image data D0G for the second display element 106G and the third image data D0B for the third display element 106B is set to 0. In this example, I Since the second image signal S also includes information to turn on all of the applied voltages to the first display element 106R, the second display element 106G, and the third display element 106B, the signal processing unit 22 I In the frame, the second image signal S I On the other hand, the signal processing unit 22 converts the first image data D0R into a gray scale of 1 or more according to the signal value of the second image signal S I Regardless of the signal value of the second image signal S, the gradation of the second image data D0G and the third image data D0B is set to 0.I In the frame, the first subframe data D1R is generated so as to include a period in which the data is 1, while the second subframe data D1G and the third subframe data D1B are generated so as not to include a period in which the data is 1, that is, the second image signal S I In the example of FIG. 7, in this embodiment, the first subframe data D1R is 1 from time t2a to time t3, and the second subframe data D1G and the third subframe data D1B are 0 from time t2 to time t3, and the pixel control unit 28 turns on the voltage applied to the first display element 106R from time t2a to time t3, and turns off the voltage applied to the second display element 106G and the third display element 106B for the entire period from time t2 to time t3. In this way, the second image signal S I In the frame, the pixel control unit 28 outputs the second image signal S I While controlling the voltage applied to the first display element 106R according to the signal value of I Regardless of the signal value of the second image signal S I During the entire period of this frame, the voltage applied to the second display element 106G and the third display element 106B is turned off.

[0060] In this embodiment, since the control is performed as described above, the output light response degree AG of the second display element 106G and the output light response degree AB of the third display element 106B behave as shown in FIG. 7. That is, since the second subframe data D1G and the third subframe data D1B are 0 from time t1 to time t2, the output light response degrees AG and AB are in a non-display orientation at time t2 when the first illumination light (visible light) is irradiated (the portion of the dashed circle in FIG. 7). Therefore, in this embodiment, it is possible to prevent the visible light image (i.e., the green image light GM and the blue image light BM) by the second display element 106G and the third display element 106B from being displayed until time t2a. Note that the output light response degree of the first display element 106R may remain after time t2, but since the output light response degrees AG and AB do not remain as described above, the luminance of the remaining image is reduced, and crosstalk can be suppressed. Furthermore, by turning on the voltage applied to the first display element 106R from time t1a to time t2, an infrared image can be appropriately displayed by the second illumination light (infrared illumination light IRL) irradiated to the first display element 106R from time t1a to time t2.

[0061] In the above description, the second image signal S I In the frame, that is, from time t1 to time t2, the voltage applied to the second display element 106G and the third display element 106B is set to 0, but it is not limited to being 0 and may be a constant value other than 0. The constant value may be set arbitrarily, but it is preferable to set it to, for example, a value smaller than the voltage applied to the first display element 106R.

[0062] In the above description, the second image signal S I In the frame, the gradation values ​​of the second image data D0G and the third image data D0B are set to a constant value (0 in this case), so that the second image signal S IIn the entire period of the frame, the second subframe data D1G and the third subframe data D1B are set to a constant value (0 in this case), and the voltages applied to the second display element 106G and the third display element 106B are set to a constant value (0 in this case). However, this is not limited to this. For example, the second image data D0G and the third image data D0B, or the second subframe data D1G and the third subframe data D1B, I However, the voltages applied to the second display element 106G and the third display element 106B may be set to a constant value (0 in this example) regardless of the calculation of the second image signal S. I In the frame, the gradation values ​​of the second image data D0G and the third image data D0B are I However, the second sub-frame data D1G and the third sub-frame data D1B may be set to a constant value (here, 0) regardless of the gradation values ​​of the second image data D0G and the third image data D0B. Furthermore, the display device 100 generates the second sub-frame data D1G and the third sub-frame data D1B according to the signal value of the second image signal S I However, the voltages applied to the second display element 106G and the third display element 106B may be constant (0 in this case) regardless of the values ​​of the second subframe data D1G and the third subframe data D1B.

[0063] In the above description, the first display element 106R, the second display element 106G, and the third display element 106B are included as the display elements 106 that display light of different colors, but the present invention is not limited thereto and may be configured to include a plurality of display elements 106. In this embodiment, the pixel control unit 28 outputs the second image signal S I In this case, the pixel control unit 28 controls the applied voltage of some of the display elements 106 in response to the signal value of the input signal, while keeping the applied voltage of the other display elements 106 (display elements different from the display elements whose applied voltage is controlled in response to the signal value of the input signal) constant regardless of the signal value of the input signal. VIn this frame, the voltage applied to all of the display elements 106 may be controlled in accordance with the signal value of the input signal.

[0064] In addition, the plurality of display elements 106 receive the second image signal S I In the frame, the display elements (part of the display elements) are irradiated with the second illumination light from the second light source 102, and the second image signal S I In other words, the first illumination light from the first light source 101 includes display elements (other display elements) that are not irradiated with the second illumination light from the second light source 102 in the frame. In this case, the first illumination light from the first light source 101 is V In this frame, the second illumination light from the second light source 102 is irradiated not only to the display elements that are irradiated with the second illumination light from the second light source 102 but also to the display elements that are not irradiated with the second illumination light from the second light source 102.

[0065] As described above, the display device 100 according to this embodiment includes a plurality of display elements 106, a first light source 101 that emits a first illumination light that is light in a first wavelength band, a second light source 102 that emits a second illumination light that is light in a second wavelength band, a signal synthesis unit 20, a pixel control unit 28, and a light source control unit 24. The signal synthesis unit 20 receives an input signal, i.e., a first image signal S V and the second image signal S I A first image signal S for displaying an image based on the first illumination light based on the first image signal S V and a second image signal S for displaying an image based on the second illumination light. I A mixed image signal S F The light source control unit 24 controls the first light source 101 and the second light source 102. The pixel control unit 28 generates a mixed image signal S F The pixel control unit 28 controls the voltage applied to the display element 106 based on the second image signal S IIn the frame (a), the display device 100 controls the applied voltage of some of the display elements 106 according to the signal value of the input signal, while keeping the applied voltage of the other display elements 106 constant regardless of the signal value of the input signal. In the display device 100 according to the present embodiment, the applied voltage of the other display elements is kept constant during the period in which the second illumination light is irradiated, so that the output light response degree (output light response degrees AG, AB in the example of the present embodiment) of the other display elements due to the light from the second light source 102 can be lowered (the orientation of the liquid crystal can be set to a non-display orientation) at a timing after the time t2 when the first light source 101 irradiates light. Therefore, when the first light source 101 starts irradiating light, the output light response degree of the other display elements can be suppressed from remaining, and crosstalk can be suppressed when an image based on the light from the first light source 101 is displayed. In addition, since the applied voltage of some display elements is controlled according to the input signal, it is possible to appropriately display an image based on the light from the second light source 102.

[0066] Furthermore, the pixel control unit 28 turns off the voltage applied to the other display elements during the period when the second illumination light is applied. By turning off the voltage applied to the other display elements, the display device 100 according to this embodiment can more suitably suppress the remaining output light response degrees (output light response degrees AG, AB in the example of this embodiment) of the other display elements, thereby suppressing crosstalk when displaying an image based on the light from the first light source 101.

[0067] Furthermore, the light source control unit 24 causes the first light source 101 to irradiate all of the display elements 106 with the first illumination light, and causes the second light source 102 to irradiate only some of the display elements with the second illumination light. The display device 100 according to this embodiment controls the voltage applied to the some of the display elements that irradiate the second illumination light in response to an input signal, and therefore, it becomes possible to appropriately display an image based on the light from the second light source 102.

[0068] The first illumination light is visible light, and the second illumination light is infrared light. The display device 100 according to this embodiment can appropriately suppress crosstalk when displaying a visible light image and an infrared light image in a time-division manner.

[0069] The display elements 106 include a first display element 106R as a part of the display elements, and a second display element 106G and a third display element 106B as other parts of the display elements. The first light source 101 irradiates the first display element 106R with red visible light, irradiates the second display element 106G with green visible light, and irradiates the third display element 106B with blue visible light. The display device 100 according to this embodiment can appropriately suppress crosstalk by turning off the voltage applied to the second display element 106G and the third display element 106B for realizing green and blue colors.

[0070] 8 is a schematic diagram illustrating an image display according to another example of the present embodiment. As shown in FIG. 8, the display device 100 receives a second image signal S I In the frame, the voltage applied to the second display element 106G and the third display element 106B is turned off, and the phase of the subframe data D1 is changed to the first light source control signal S LV and the second light source control signal S LI For example, in the example of FIG. 8, the phase of the subframe data D1 may be shifted from the phase of the first light source control signal S LV and the second light source control signal S LI Therefore, the phase of the second image signal S I The time (time t1b) at which the first subframe data D1R, which is set based on the signal value of LI becomes 0, the timing is before time t2, and the first image signal S V The time (time t2b) at which the first subframe data D1R, which is set based on the signal value of LVThis is the timing before time t3 (time t1) when becomes 0. By shifting the phase in this manner, it is possible to decrease the output light response degree AR of the first display element 106R from time t1b, and the output light response degree AR is prevented from remaining during the period from time t2 when a visible light image is displayed (the portion surrounded by a dashed circle in FIG. 8), and crosstalk caused by the first display element 106R can also be appropriately suppressed.

[0071] Although the embodiments and modifications of the present invention have been described above, the embodiments are not limited by the contents of these embodiments and modifications. The above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be appropriately combined, and the configurations of each embodiment and modification can also be combined. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the gist of the above-described embodiments and modifications. [Explanation of symbols]

[0072] 10 Display mechanism 12 Control section 20 Signal synthesis section 22 Signal Processing Section 24 Light source control unit 26 Subframe data generator 28 Pixel control unit 100 display device 101 1st light source 102 Second light source 106B Third display element 106G Second display element 106R First display element D0 Image data D1 Subframe Data S F Mixed Image Signal S V First image signal S I Second Image Signal

Claims

1. A plurality of display elements; a first light source that emits a first illumination light that is light of a first wavelength band; a second light source that emits second illumination light that is light in a second wavelength band; a signal synthesis unit that generates a mixed image signal in which frames of a first image signal for displaying an image based on the first illumination light and frames of a second image signal for displaying an image based on the second illumination light are alternately repeated based on an input signal; a pixel control unit that controls an applied voltage to the display element based on the mixed image signal; a light source control unit that controls the first light source and the second light source; Equipped with the plurality of display elements include a first display element corresponding to the first separated light and a second separated light obtained by separating the first illumination light for each wavelength, and a second display element corresponding to the second separated light having a wavelength different from that of the first separated light, The pixel control unit during a period in which the second illumination light is irradiated, a voltage applied to the first display element among the plurality of display elements is controlled in accordance with a signal value of the input signal, while a voltage applied to the second display element among the plurality of display elements that is not controlled in accordance with the signal value of the input signal is set to a constant value regardless of the signal value of the input signal; the first illumination light is visible light, and the second illumination light is infrared light; the plurality of display elements include a red display element as the first display element, and a green display element and a blue display element as the second display element, the first light source irradiates the red display element with red visible light, the green display element with green visible light, and the blue display element with blue visible light; Display device.

2. The display device according to claim 1 , wherein the pixel control unit turns off a voltage applied to the second display element during a period in which the second illumination light is emitted.

3. The light source control unit is causing the first light source to irradiate all of the display elements with the first illumination light; The display device according to claim 1 , wherein the second light source is configured to irradiate the second illumination light only onto the first display element.

4. A method for controlling a display device including a plurality of display elements, a first light source that irradiates a first illumination light that is light in a first wavelength band, and a second light source that irradiates a second illumination light that is light in a second wavelength band, wherein the plurality of display elements include a first display element corresponding to the first separated light, and a second display element corresponding to the second separated light having a wavelength different from that of the first separated light, of first separated light and second separated light obtained by separating the first illumination light by wavelength, a signal synthesis step of generating a mixed image signal in which frames of a first image signal for displaying an image based on the first illumination light and frames of a second image signal for displaying an image based on the second illumination light are alternately repeated based on an input signal; a pixel control step of controlling an applied voltage of the display element based on the mixed image signal; a light source control step of controlling the first light source and the second light source; Including, In the pixel control step, during a period in which the second illumination light is irradiated, a voltage applied to the first display element among the plurality of display elements is controlled in accordance with a signal value of the input signal, while a voltage applied to the second display element among the plurality of display elements that is not controlled in accordance with the signal value of the input signal is set to a constant value regardless of the signal value of the input signal; the first illumination light is visible light, and the second illumination light is infrared light; the plurality of display elements include a red display element as the first display element, and a green display element and a blue display element as the second display element, the first light source irradiates the red display element with red visible light, the green display element with green visible light, and the blue display element with blue visible light; A method for controlling a display device.

Images