Projection-type video display device and video display control method

Abstract

This projection-type video display device comprises: an optical modulation element that uses light from red, green, and blue light sources to form an image including a plurality of pixels; a movable unit capable of transitioning so as to displace the optical axis of light reflected by the optical modulation element; an image control unit that expresses the hue and gradation of each pixel by controlling the optical modulation element on the basis of the usage setting of each segment in a subframe including a plurality of segments corresponding to red, a plurality of segments corresponding to green, and a plurality of segments corresponding to blue; and a movement control unit that causes the movable unit to transition on the basis of the cycle of the subframe. The image control unit sets, on the basis of the gradation of the pixels corresponding to the subframe, whether or not to use each segment in the subframe.

Description

Projection-type image display device and image display control method 【0001】 This disclosure relates to a projection-type image display device and an image display control method. 【0002】 In projectors, there is a well-known technique called pixel shifting (also known as wobbling or pixel shifting) that increases the resolution of projected images. 【0003】 Patent Document 1 discloses a projector comprising: an optical modulation element (DMD) that forms an image using light from a light source; an optical unit that guides light from the light source to the optical modulation element and projects the image formed by the optical modulation element; a drive unit that periodically displaces the optical modulation element; and an image control unit that creates a moving-period image without color information for a predetermined period that includes at least the point in time when the moving speed of the optical modulation element is fastest during the periodic displacement of the optical modulation element, and controls the projection of the moving-period image. 【0004】 Japanese Patent Publication No. 2018-5000 【0005】 However, image quality tends to degrade during the pixel shifting process, leaving room for further improvement. 【0006】 This disclosure aims to provide a technology for improving image quality in pixel shifting. 【0007】 One aspect of the present disclosure provides a projection-type image display device comprising: an optical modulation element that forms an image including a plurality of pixels using light from red, green, and blue light sources; a movable unit that can transition to displace the optical axis of the light reflected by the optical modulation element; an image control unit that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe including a plurality of segments corresponding to red, a plurality of segments corresponding to green, and a plurality of segments corresponding to blue; and a movement control unit that transitions the movable unit based on the period of the subframe, wherein the image control unit sets whether or not to use each segment in the subframe based on the gradation of the pixels corresponding to the subframe. 【0008】One aspect of the present disclosure provides a video display control method for controlling an optical modulation element that forms an image including a plurality of pixels using light from red, green, and blue light sources, and a movable unit that is transitionable to displace the optical axis of the light reflected by the optical modulation element, wherein the method includes image control that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe including a plurality of segments corresponding to red, a plurality of segments corresponding to green, and a plurality of segments corresponding to blue, and movement control that transitions the movable unit based on the period of the subframe, wherein the image control sets whether or not each segment in the subframe is used based on the gradation of the pixels corresponding to the subframe. 【0009】 These comprehensive or specific embodiments may be implemented as systems, devices, methods, integrated circuits, computer programs, or recording media, or as any combination of systems, devices, methods, integrated circuits, computer programs, and recording media. 【0010】 According to this disclosure, it is possible to improve image quality in pixel shifting. 【0011】 A schematic diagram showing the optical configuration of the projection-type video display device according to Embodiment 1. A schematic diagram showing the RGB light source unit in Embodiment 1. A schematic diagram showing the excitation light source unit in Embodiment 1. A schematic diagram showing the phosphor wheel in Embodiment 1. A spectral diagram of color light in the projection-type video display device of Embodiment 1. A block diagram showing an example of the functional configuration of the control device according to Embodiment 1. A diagram explaining the relationship between the input image and pixel shift due to wobbling according to Embodiment 1. A graph showing the change in the transition amount of the movable unit during wobbling according to Embodiment 1. A diagram for explaining the relationship between subframes, segments and pixel shift in the prior art. A graph showing the relationship between signal level and gradation according to Embodiment 1. A diagram for explaining the relationship between gradation and the usage setting of segments in subframes according to Embodiment 1. 【0012】Embodiments of the present disclosure will be described in detail below, with appropriate reference to the drawings. However, descriptions that are unnecessarily detailed may be omitted. For example, detailed descriptions of already well-known matters and redundant descriptions of substantially identical configurations may be omitted. This is to avoid the following description becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure and are not intended to limit the subject matter of the claims. The functions of one configuration shown in this embodiment may be realized by two or more physical configurations, or the functions of two or more configurations may be realized by, for example, one physical configuration. 【0013】 (Embodiment 1) <Projection-type image display device> First, the configuration of the projection-type image display device 100 according to Embodiment 1 will be described. Figure 1 is a schematic diagram showing the optical configuration of the projection-type image display device 100 according to Embodiment 1. Note that the projection-type image display device 100 may be read as a projector. Embodiment 1 will illustrate the case in which red component light R, green component light G, blue component light B, and yellow component light Ye are used as the image light. 【0014】 As shown in Figure 1, firstly, the projection-type image display device 100 includes a phosphor wheel 30, a dichroic mirror 40, a rod integrator 50, a DMD (Digital Mirror Device) 60, a projection unit 70, and a light source device 150. The light source device 150 includes an RGB light source unit 10, an excitation light source unit 20, and a control device 180. 【0015】 The control device 180 may be composed of, for example, a processor, an LSI (Large Scale Integration), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit). The control device 180 may also include a storage unit composed of a volatile storage medium and / or a non-volatile storage medium. 【0016】Figure 2 is a schematic diagram showing the RGB light source unit 10 in Embodiment 1. As shown in Figure 2, the RGB light source unit 10 is composed of a red light source 10R, a green light source 10G, a blue light source 10B, a mirror 14R, a dichroic mirror 14G, and a dichroic mirror 14B. The red light source 10R is composed of a red light source heat dissipation substrate 11R, a plurality of red light source emitters 12R, and a plurality of red light source collimating lenses 13R. The green light source 10G is composed of a green light source heat dissipation substrate 11G, a plurality of green light source emitters 12G, and a plurality of green light source collimating lenses 13G. The blue light source 10B is composed of a blue light source heat dissipation substrate 11B, a plurality of blue light source emitters 12B, and a plurality of blue light source collimating lenses 13B. The red light source emitter 12R, the green light source emitter 12G, and the blue light source emitter 12B are composed of, for example, laser diodes (LDs) or light-emitting diodes (LEDs). In this embodiment, the red light source emitter 12R is composed of a red laser diode that emits light with a main wavelength of 642 nm (red component light R), the green light source emitter 12G is composed of a green laser diode that emits light with a main wavelength of 525 nm (green component light G), and the blue light source emitter is composed of a blue laser diode that emits light with a main wavelength of 465 nm (blue component light B). However, these wavelengths are not limited; for example, the main wavelength of the red light source emitter 12R may be 630 to 650 nm, the main wavelength of the green light source emitter 12G may be 515 to 535 nm, and the main wavelength of the blue light source emitter 12B may be 440 to 470 nm. 【0017】Mirror 14R reflects the light emitted from the red light source 10R. Dichroic mirror 14G reflects the light emitted from the green light source 10G and transmits the light emitted from the red light source 10R that has been reflected by mirror 14R. Dichroic mirror 14B reflects the light emitted from the blue light source 10B, transmits the light emitted from the red light source 10R that has been reflected by mirror 14R and transmitted by dichroic mirror 14B, and transmits the light emitted from the green light source 10G that has been reflected by dichroic mirror 14G. Therefore, the light emitted from the RGB light source unit 10 is white light, which is a combination of light with a dominant wavelength of 642 nm (red component light R), light with a dominant wavelength of 525 nm (green component light G), and light with a dominant wavelength of 465 nm (blue component light B). 【0018】 Figure 3 is a schematic diagram showing the excitation light source unit 20 in Embodiment 1. As shown in Figure 3, the excitation light source unit 20 consists of an excitation light source 20Ex and a mirror 24. The excitation light source 20Ex consists of an excitation light source heat dissipation substrate 21, a plurality of excitation light source emitters 22, and a plurality of excitation light source collimating lenses 23. The excitation light source emitters 22 are, for example, laser diodes (LD) or light-emitting diodes (LED). 【0019】 In this embodiment, the excitation light source emitter 22 is composed of a blue laser diode that emits light with a main wavelength of 455 nm (excitation light Ex). However, this wavelength is not limited; for example, the main wavelength of the excitation light source emitter 22 may be 440 to 470 nm, or it may be the same main wavelength as the blue light source emitter 12B. 【0020】 Figure 4 is a schematic diagram showing the phosphor wheel 30 in Embodiment 1. As shown in Figure 4, the phosphor wheel 30 is composed of a substrate 31, a reflective film 32 formed on the substrate 31, a phosphor film 33 coated in an annular shape on the reflective film 32, and a motor 34 for rotating the substrate 31. The phosphor wheel 30 is an example of a wavelength conversion element. Figure 4(a) is a view of the phosphor wheel in the z direction of Figure 1, and Figure 4(b) is a view of the phosphor wheel in the y direction of Figure 1. 【0021】 The phosphor film 33 is composed of a yellow phosphor film that emits yellow light when irradiated with excitation light Ex. In Figure 4(a), the symbols in parentheses indicate that the components with symbols not in parentheses are located on the upper layer. That is, Figure 4(a) shows that the reflective film 32 is placed on the substrate 31, and the phosphor film 33 is placed on the reflective film 32. 【0022】 The phosphor film 33 is composed of a yellow phosphor film that emits yellow light (light with a main wavelength of 560-590 nm) when irradiated with excitation light. The yellow light mentioned above is an example of colored light output by a wavelength conversion element. The phosphor film 33 can be manufactured, for example, by mixing ceramic phosphor powder with an adhesive (silicone resin), coating it onto a substrate, and curing it at a high temperature. Examples of ceramic phosphors used in the phosphor film 33 include cerium-equipped active garnet structure phosphors such as YAG phosphors and LAG phosphors. 【0023】 As the phosphor wheel 30 rotates with the motor 34, the position to which the excitation light is irradiated changes circumferentially, and emitted light Ye is emitted from the phosphor film 33. In this embodiment, a phosphor wheel 30 is used, but a stationary, non-rotating fluorescent light source may also be used. 【0024】 Returning to Figure 1, the dichroic mirror 40 transmits red component light R, green component light G, and blue component light B, and emits light Ye ０ Yellow component light Ye １ It has a coating property that reflects light. 【0025】 Referring to Figure 1, we will first explain the optical paths of the red component light R, the green component light G, and the blue component light B. The light emitted from the RGB light source unit 10 (red component light R, green component light G, and blue component light B) is guided to the rod integrator 50 via mirror 111, diffuser plate 112, lens 113, mirror 114, diffuser plate 115, mirror 116, lens 117, dichroic mirror 40, lens 118, mirror 119, and lens 121. 【0026】 Mirrors 111, 114, and 116 are reflective mirrors that reflect red component light R, green component light G, and blue component light B. 【0027】 Mirror 119 is a reflective mirror that reflects red component light R, green component light G, blue component light B, and yellow component light Ye. １ It is a reflective mirror that reflects the light. 【0028】 Diffusion plates 112 and 115 are diffusion plates that adjust the divergence angle of red component light R, green component light G, and blue component light B. 【0029】 Lens 113 is a lens that condenses red component light R, green component light G, and blue component light B near diffusion plate 115. At this time, the size and shape of the condensing spot formed on diffusion plate 115 are determined according to the diffusion angle characteristics of diffusion plate 112. Lens 117 is a lens that substantially parallelizes the divergent light emitted from diffusion plate 115. Lenses 118 and 121 are lenses that condense the light substantially parallelized by lens 117 onto rod integrator 50. At this time, the condensing spot formed on diffusion plate 115 is substantially imaged on the incident surface of rod integrator 50 via lenses 117, 118, and 121 (the incident surface of diffusion plate 115 and rod integrator 50 are substantially conjugate). 【0030】 Next, the optical paths of excitation light Ex, emission light Ye ０ , and yellow component light Ye １ will be described. The emitted light (excitation light Ex) from excitation light source unit 20 is irradiated onto phosphor wheel 30 via diffusion plate 122, dichroic mirror 40, lenses 123, and lens 124. Due to the irradiation of excitation light Ex, emission light Ye ０ is emitted from phosphor wheel 30. Emission light Ye ０ is guided to rod integrator 50 via lens 124, lens 123, dichroic mirror 40, lens 118, mirror 119, and lens 121. At this time, emission light Ye ０ is reflected by dichroic mirror 40 and becomes yellow component light Ye １ . 【0031】 Diffusion plate 122 is a diffusion plate that adjusts the divergence angle of excitation light Ex. 【0032】Lenses 123 and 124 are lenses that focus the excitation light Ex onto the surface of the phosphor wheel 30. At this time, the size and shape of the focused spot formed on the phosphor wheel 30 are determined according to the diffusion angle characteristics of the diffuser plate 122. Lenses 123 and 124 also focus the emitted light Ye from the phosphor wheel 30. ０ To make the light approximately parallel. 【0033】 Lenses 118 and 121 are lenses that focus the light, which has been made into approximately parallel light by lenses 123 and 124, onto the rod integrator 50. At this time, the emitted light Ye from the phosphor wheel 30 ０ The phosphor is substantially imaged onto the incident surface of the rod integrator 50 via lenses 124, 123, 118, and 121 (the exit surface of the phosphor wheel 30 and the incident surface of the rod integrator 50 are substantially conjugate). 【0034】 Figure 5 is a spectral diagram of color light in the projection-type image display device 100 of Embodiment 1. Figure 5 shows the spectra of each color light. The dichroic mirror 40 transmits excitation light Ex, blue component light B, green component light G, and red component light R, and emits light Ye ０ Of these, the yellow component light Ye １ It reflects the yellow component light Ye １ The wavelength band is located between the green component light (525 nm) and the red component light (642 nm), and is mainly light between 525 and 642 nm. That is, yellow component light Ye １ The dominant wavelength is 525-642 nm. In this example, the yellow component light Ye １ The dominant wavelength is 575 nm. However, the yellow component light Ye １ The wavelength band can be any other major wavelength as long as it is within the yellow wavelength band (560-590 nm). 【0035】 The rod integrator 50 is a solid rod made of a transparent material such as glass. The rod integrator 50 homogenizes the light emitted from the RGB light source unit 10 and the light emitted from the phosphor wheel 30. The rod integrator 50 may also be a hollow rod whose inner wall is made of a mirror surface. The rod integrator 50 is an example of a light homogenization element. 【0036】 The light emitted from the rod integrator 50 passes through the lenses 131, 132, and 133, enters the total reflection prism composed of the triangular prism 141 and the triangular prism 142, and then enters the DMD 60. The DMD 60 may be read as an optical modulation element. 【0037】 The DMD 60 modulates each color component light (red component light R, green component light G, blue component light B, yellow component light Ye) generated by the RGB light source unit 10 and the phosphor wheel 30 in a time-sharing manner. Specifically, the DMD 60 is composed of a plurality of micromirrors, and the plurality of micromirrors are movable. Each micromirror basically corresponds to one pixel. The DMD 60 switches whether to reflect light to the projection unit 70 side by a modulation operation of changing the angle of each micromirror according to the video signal. 【0038】 Further, the movable unit 61 is disposed between the triangular prism 142 and the projection unit 70. The movable unit 61 wobbles to displace the optical axis of the light reflected by the DMD 60, thereby realizing pixel shift. Thereby, a high-resolution feeling of the video projected from the projection unit 70 onto the screen is realized. 【0039】 FIG. 6 is a block diagram showing a functional configuration example of the control device 180 according to the first embodiment. 【0040】 The control device 180 includes, as functions, an image control unit 201, a movement control unit 202, and a light source control unit 203. 【0041】The image control unit 201 sets whether to use the multiple segments 401R corresponding to red, multiple segments 401G corresponding to green, and multiple segments 401B corresponding to blue that constitute the subframe 400 (see Figure 11) based on the input image input from an external I / F (not shown). Each segment 401 represents the hue and gradation of one pixel that constitutes the input image. The image control unit 201 controls the ON / OFF state of one of the micro-mirrors of the DMD 60 based on whether to use the multiple segments 401 that constitute the subframe 400. The image control unit 201 generates an image to be projected onto the screen by similarly controlling the ON / OFF state of each micro-mirror of the DMD 60 for each pixel that constitutes the input image. 【0042】 The motion control unit 202 performs wobbling control of the movable unit 61 equipped with the DMD 60 based on the period of the subframe 400, thereby achieving pixel shifting. This makes it possible to increase the resolution of the image projected onto the screen to a level higher than the resolution of the DMD 60. 【0043】 The light source control unit 203 controls the power supplied to the red light source 10R, the green light source 10G, and the blue light source 10B, thereby controlling the amount of light emitted from the red light source 10R, the green light source 10G, and the blue light source 10B. 【0044】 Figure 7 illustrates the relationship between the input image and pixel shifting due to wobbling according to Embodiment 1. 【0045】 As shown in Figure 7, assume that as part of the input image, pixel 2 is aligned to the right of pixel 1, pixel 3 is aligned below pixel 2, pixel 4 is aligned to the left of pixel 3, and pixel 1 is aligned above pixel 4. Pixel shifting is performed as shown in (A1) to (A4) below. 【0046】 (A1) First, the movement control unit 202 displaces the movable unit 61 from the upper left corresponding to pixel 1 to the upper right corresponding to pixel 2. At this time, the image control unit 201 switches from controlling the DMD 60 based on the first subframe corresponding to pixel 1 to controlling the DMD 60 based on the second subframe corresponding to pixel 2. 【0047】(A2) Next, the movement control unit 202 displaces the movable unit 61 from the upper right corresponding to pixel 2 to the lower right corresponding to pixel 3. At this time, the image control unit 201 switches from controlling the DMD 60 based on the second subframe corresponding to pixel 2 to controlling the DMD 60 based on the third subframe corresponding to pixel 3. 【0048】 (A3) Next, the movement control unit 202 displaces the movable unit 61 from the lower right corresponding to pixel 3 to the lower left corresponding to pixel 4. At this time, the image control unit 201 switches from controlling the DMD 60 based on the third subframe corresponding to pixel 3 to controlling the DMD 60 based on the fourth subframe corresponding to pixel 4. 【0049】 (A4) Finally, the movement control unit 202 displaces the movable unit 61 from the lower left corresponding to pixel 4 to the upper left corresponding to pixel 1. At this time, the image control unit 201 switches from controlling the DMD 60 based on the fourth subframe corresponding to pixel 4 to controlling the DMD 60 based on the first subframe corresponding to pixel 1. 【0050】 By repeating the wobbling process described in (A1) through (A4) above, four times the number of pixels can be represented by a single micro-mirror of the DMD60. Therefore, through wobbling, an image with four times the resolution of the micro-mirror of the DMD60 can be projected onto the screen. 【0051】 Figure 8 is a graph showing the change in the amount of transition of the movable unit 61 during wobbling according to Embodiment 1. 【0052】 In the graph 250 shown in Figure 8, the horizontal axis represents time, and the vertical axis represents the transition amount (displacement amount) of the movable unit 61. 【0053】 For example, when performing a pixel shift from pixel 1 to pixel 2 by wobbling, as shown in graph 250 of Figure 8, the amount of transition of the movable unit 61 is small (i.e., it doesn't move much) near the center of the first subframe 400A, and the amount of transition of the movable unit 61 is large (it moves a lot) near the point where it switches from the first subframe 400A to the second subframe 400B. 【0054】Hereinafter, the period when the amount of transition is large before and after the switching of subframe 400 will be referred to as the high transition period 291, and the period of subframe 400 other than the high transition period will be referred to as the low transition period 292. 【0055】 Figure 9 is a diagram illustrating the relationship between subframes, segments, and pixel shifting in the prior art. 【0056】 In wobbling, during the pixel shift from pixel 1 to pixel 2, the color of pixel 1 moves toward pixel 2, which can make pixel 1 appear larger, reducing the perceived resolution and potentially causing false contours. 【0057】 To address this challenge, conventional technology, as shown in Figure 9, places red, green, and blue segments during the low transition period of the subframe, and white segments during the high transition period. 【0058】 As a result, during high-transition periods where pixels move significantly from pixel 1 to pixel 2, the movement of the white pixel 1 towards pixel 2 becomes less noticeable, suppressing a decrease in perceived resolution and making false contours less visible. Furthermore, compared to cases where black segments are placed during high-transition periods in subframes, the decrease in pixel brightness is suppressed. 【0059】 However, the high transition period is relatively long, for example, 1 to 2 ms. If a white segment is placed during this period, the segments to which red, green, and blue can be assigned become shorter, resulting in a decrease in the brightness of these primary colors. 【0060】 This embodiment discloses a method for suppressing the decrease in perceived resolution and the decrease in the brightness of primary colors during wobbling. 【0061】 Figure 10 is a graph 300 showing the relationship between signal level and grayscale according to Embodiment 1. 【0062】 In the graph 300 shown in Figure 10, the horizontal axis represents the signal level, and the vertical axis represents the grayscale. As shown in Figure 10, the grayscale increases as the signal level increases. 【0063】Here, as shown in graph 300 of Figure 10, the range of predetermined gradations including the maximum gradation is referred to as the high gradation range 302, and the range of signal levels corresponding to the high gradation range 302 is referred to as the high signal level range 301. 【0064】 Furthermore, for the purposes of the explanation described later, the gradation when the first signal level 331 is outside the high signal level range 301 will be referred to as the first gradation 341. The gradation when the second signal level 332 is outside the high signal level range 301 and greater than the first signal level 331 will be referred to as the second gradation 342. The gradation when the third signal level 333 is within the high signal level range 301 will be referred to as the third gradation 343. 【0065】 Figure 11 is a diagram illustrating the relationship between gradation and the range of segment usage in a subframe according to Embodiment 1. Figure 11(a) shows an example of segment usage in a subframe when the first gradation 341 is shown in graph 300 of Figure 10. Figure 11(b) shows an example of segment usage in a subframe when the second gradation 342 is shown in graph 300 of Figure 10. Figure 11(c) shows an example of segment usage in a subframe when the third gradation 343 is shown in graph 300 of Figure 10. Note that Figures 11(a), (b), and (c) are examples when grayscale pixels are displayed, but this embodiment is applicable when displaying pixels of any hue. 【0066】 As shown in Figures 8 and 11, the area near the center of subframe 400 corresponds to the low transition period 292, and the area before and after subframe 400 switches corresponds to the high transition period 291. 【0067】 The image control unit 201 sets whether or not to use each segment 401 in the subframe 400 based on the grayscale of the pixels corresponding to the subframe 400. 【0068】For example, as shown in Figures 11(a) and (b), when the image control unit 201 displays pixels with low gradation (e.g., first gradation 341, second gradation 342) that do not belong to the high gradation range 302 (i.e., below the lower threshold of the high gradation range 302), it preferentially uses segments belonging to the low transition period 292 of the subframe 400 to represent the hue of those low gradations (e.g., first gradation 341, second gradation 342). 【0069】 In other words, as shown in Figures 11(a) and (b), when representing low gradations that do not belong to the high gradation range 302, the hue of that gradation is represented without using the segment 401 belonging to the high transition period 291 of the subframe. 【0070】 As a result, when displaying low-gradation pixels, for example, during the high transition period 291 when switching from the first subframe 400A to the second subframe 400B, the minute mirror of the DMD 60 is turned OFF while the pixel is shifting from pixel 1 to pixel 2. Therefore, as the black pixel 1 moves toward pixel 2, the movement of pixel 1 becomes less noticeable, and the decrease in perceived resolution can be suppressed. 【0071】 For example, as shown in Figure 11(c), when the image control unit 201 displays pixels of a gradation (e.g., a third gradation 343) belonging to the high gradation range 302 (i.e., above the lower threshold of the high gradation range 302), it uses not only the segment 401 belonging to the low transition period 292 of the subframe 400 but also the segment 401 belonging to the high transition period 291 of the subframe 400 to represent the hue of that gradation (e.g., the third gradation 343). 【0072】 As a result, compared to the conventional technology described in Figure 9, this embodiment allows the use of red, green, and blue segments 401 in the high transition period 291 of the subframe 400 when displaying high-gradation pixels, thereby suppressing a decrease in the brightness of the primary colors. 【0073】 (Summary of this disclosure) Based on the description of Embodiment 1 above, the following technology is disclosed. 【0074】<Technology 1> A projection-type image display device (100) according to one embodiment includes an optical modulation element (e.g., DMD 60) that forms an image including multiple pixels using light from red, green, and blue light sources; a movable unit (61) that can transition to displace the optical axis of the light reflected by the optical modulation element; an image control unit (201) that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe (400) including a plurality of segments corresponding to red (401R), a plurality of segments corresponding to green (401G), and a plurality of segments corresponding to blue (401B); and a movement control unit (202) that transitions the movable unit based on the period of the subframe, wherein the image control unit sets whether or not to use each segment in the subframe based on the gradation of the pixels corresponding to the subframe. This makes it possible to improve image quality in pixel shifting. 【0075】 <Technology 2> In the projection-type image display device described in Technology 1, the motion control unit moves the movable unit such that the amount of transition in the first period before and after the subframe is switched is greater than the amount of transition in the second period when the subframe is not switched, and the image control unit is set to use the segment of the subframe included in the first period. As a result, the segment of the subframe included in the first period, in which the amount of transition of the movable unit is large, can also be used, thereby suppressing a decrease in the brightness of the primary colors. 【0076】 <Technology 3> In the projection-type image display device described in Technology 2, the image control unit does not use the segment included in the first period of the subframe if the gradation of the pixel corresponding to the subframe is below a predetermined threshold. As a result, when the pixel has a low gradation, the segment of the subframe included in the first period, in which the transition amount of the movable unit is large, is not used, so the movement of the pixel in pixel shifting becomes less noticeable, and a decrease in perceived resolution can be suppressed. 【0077】<Technology 4> In the projection-type image display device described in Technology 3, the image control unit uses a segment included in the first period of the subframe when the gradation of the pixel corresponding to the subframe is equal to or greater than the threshold. As a result, when the pixel has high gradation, a segment of the subframe included in the first period, in which the transition amount of the movable unit is large, is also used, thereby suppressing a decrease in the brightness of the primary color. 【0078】 <Technology 5> A video display control method that controls an optical modulation element (e.g., DMD 60) that forms an image containing multiple pixels using light from red, green, and blue light sources, and a movable unit (61) that can transition to displace the optical axis of the light reflected by the optical modulation element, performs image control that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe (400) which includes multiple segments corresponding to red (401R), multiple segments corresponding to green (401G), and multiple segments corresponding to blue (401B), and moves the movable unit to transition based on the period of the subframe, wherein the image control sets whether or not to use each segment in the subframe based on the gradation of the pixels corresponding to the subframe. This makes it possible to improve image quality in pixel shifting. 【0079】 While embodiments have been described above with reference to the attached drawings, this disclosure is not limited to such examples. It is clear to those skilled in the art that various modifications, alterations, substitutions, additions, deletions, and equivalents can be conceived within the scope of the claims, and these are also understood to fall within the technical scope of this disclosure. Furthermore, the components of the embodiments described above can be combined in any way without departing from the spirit of the invention. 【0080】 The technology disclosed herein is useful for projection-type image display devices and projectors, etc. 【0081】10 RGB light source unit 10B Blue light source 10G Green light source 10R Red light source 11B Blue light source heat dissipation substrate 11G Green light source heat dissipation substrate 11R Red light source heat dissipation substrate 12B Blue light source emitter 12G Green light source emitter 12R Red light source emitter 13B Blue light source collimating lens 13G Green light source collimating lens 13R Red light source collimating lens 14B, 14G, 40 Dichroic mirrors 14R, 24, 111, 114, 116, 119 Mirrors 20 Excitation light source unit 20Ex Excitation light source 21 Excitation light source heat dissipation substrate 22 Excitation light source emitter 23 Excitation light source collimating lens 30 Phosphor wheel 31 Substrate 32 Reflective film 33 Phosphor film 34 Motor 50 Rod integrator 60 DMD 61 Movable Unit 70 Projection Unit 100 Projection-type Image Display Device 112, 115, 122 Diffuser Plate 113, 117, 118, 121, 123, 124, 131, 132, 133 Lens 141, 142 Triangular Prism 150 Light Source Device 180 Control Device 201 Image Control Unit 202 Movement Control Unit 203 Light Source Control Unit 210 External I / F 250 Graph 291 High Transition Period 292 Low Transition Period 300 Graph 301 High Signal Level Range 302 High Tone Range 331 First Signal Level 332 Second Signal Level 333 Third Signal Level 341 First Tone 342 Second Tone 343 Third Tone 400, 400A, 400B subframes; 401, 401R, 401G, 401B segments.

Claims

1. A projection-type image display device comprising: an optical modulation element that forms an image including multiple pixels using light from red, green, and blue light sources; a movable unit that can be transitioned to displace the optical axis of the light reflected by the optical modulation element; an image control unit that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe including multiple segments corresponding to red, multiple segments corresponding to green, and multiple segments corresponding to blue; and a movement control unit that transitions the movable unit based on the period of the subframe, wherein the movement control unit transitions the movable unit such that the amount of transition in a first period before and after the subframe switches is greater than the amount of transition in a second period when the subframe does not switch; and the image control unit sets whether or not to use the segments included in the first period of the subframe based on the gradation of the pixels corresponding to the subframe.

2. The projection-type video display device according to claim 1, wherein the image control unit does not use a segment included in the first period of the subframe if the grayscale of a pixel corresponding to the subframe is less than a predetermined threshold.

3. The projection-type video display device according to claim 2, wherein the image control unit uses a segment included in the first period of the subframe when the grayscale of the pixel corresponding to the subframe is equal to or greater than the threshold.

4. A video display control method for controlling an optical modulation element that forms an image including multiple pixels using light from red, green, and blue light sources, and a movable unit that can transition to displace the optical axis of the light reflected by the optical modulation element, comprising: image control that expresses the hue and gradation of each pixel by controlling the optical modulation element based on the usage settings of each segment in a subframe including multiple segments corresponding to red, multiple segments corresponding to green, and multiple segments corresponding to blue; and movement control that transitions the movable unit based on the period of the subframe, wherein in the movement control, the movable unit is transitioned such that the amount of transition in a first period before and after the subframe switches is greater than the amount of transition in a second period when the subframe does not switch; and in the image control, whether or not to use the segments included in the first period of the subframe is set based on the gradation of the pixels corresponding to the subframe.

Images