Control method for projection-type image display device and projection-type image display device

Abstract

In this control method of a projection-type image display device comprising a light source for emitting red light, a light source for emitting green light, and a light source for emitting blue light, a primary color including one of the red light, the green light, and the blue light, and at least one of a complementary color including two of the red light, the green light, and the blue light or a white color including all of the red light, the green light, and the blue light are assigned to each of a plurality of sections constituting one cycle, the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned, and turning on and off of each light source is controlled to output image light of the color assigned to each of the plurality of sections.

Description

Control method for projection-type image display device and projection-type image display device 【0001】 This disclosure relates to a control method for a projection-type image display device and a projection-type image display device. 【0002】 Patent Document 1 discloses a light source device comprising a laser optical system, a fluorescence optical system, and a photosynthesizer that combines the emitted light from the laser optical system and the fluorescence optical system, as well as a projection-type display device equipped with the light source device. In this projection-type display device, three digital micromirror devices are used as image forming means. 【0003】 Japanese Patent Publication No. 2020-177070 【0004】 This disclosure was devised in light of the conventional circumstances described above, and aims to suppress the decrease in brightness of the video light. 【0005】 This disclosure provides a control method for a projection-type image display device comprising a light source that emits red light, a light source that emits green light, and a light source that emits blue light, wherein each of a plurality of sections constituting one cycle is assigned a primary color including one of the red light, the green light, and the blue light, and at least one of a complementary color including two of the red light, the green light, and the blue light, or white including all of the red light, the green light, and the blue light, and the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned, and the on / off of each light source is controlled to output image light of the color assigned to each of the plurality of sections. 【0006】Furthermore, this disclosure provides a projection-type image display device comprising a light source that emits red light, a light source that emits green light, a light source that emits blue light, and a control device, wherein the control device controls the lighting and extinguishing of each of the light sources to output image light of a color assigned to each of a plurality of sections constituting one cycle, and each of the plurality of sections is assigned a primary color including one of the red light, the green light, and the blue light, and a complementary color including two of the red light, the green light, and the blue light, or white including all of the red light, the green light, and the blue light, and the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned. 【0007】 Furthermore, any combination of the above components, as well as any conversion of the expressions of this disclosure between methods, apparatus, systems, storage media, computer programs, etc., are also valid as aspects of this disclosure. 【0008】 According to this disclosure, it is possible to suppress the decrease in brightness of the image light. 【0009】 Schematic diagram showing the optical configuration of the projection-type video display device in Embodiment 1 Schematic diagram showing the RGB light source unit in Embodiment 1 Schematic diagram showing the excitation light source unit in Embodiment 1 Schematic diagram showing the phosphor wheel in Embodiment 1 Spectrum diagram of color light in the projection-type video display device of Embodiment 1 Schematic diagram showing an example of the subframe configuration of Embodiment 1 Schematic diagram showing an example of the video frame configuration of Embodiment 1 Spectrum diagram of color segment R in Embodiment 1 Spectrum diagram of color segment Ye in Embodiment 1 Spectrum diagram of color segment G in Embodiment 1 Spectrum diagram of color segment Cy in Embodiment 1 Spectrum diagram of color segment B in Embodiment 1 Chromaticity diagram in Embodiment 1 Chromaticity diagram in Embodiment 1 Schematic diagram for explaining the dark time during color switching Schematic diagram for explaining an example of the order of colors of video light in Embodiment 1 Schematic diagram for explaining an example of the order of colors of video light in Embodiment 1 Schematic diagram for explaining an example of the order of colors of video light in Embodiment 1 Chromaticity diagram for explaining an example of the order of colors of video light in Embodiment 1 【0010】(Background to obtaining one form of this disclosure) Conventionally, a projection-type image display device using a single digital micromirror device (hereinafter referred to as "DMD") is known, which is a single-chip DLP system. DLP stands for Digital Light Processing. In a single-chip DLP system projection-type image display device, when switching between red, green, and blue, the light sources for each color may be turned off to prevent color mixing. In this case, the brightness of the image light may decrease as the light sources for each color are turned off. Therefore, it is preferable that a single-chip DLP system projection-type image display device can prevent unwanted color mixing and suppress a decrease in the brightness of the image light. 【0011】 The embodiments will be described in detail below, with reference to the drawings as appropriate. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding by those skilled in the art. The accompanying drawings and the following explanation are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims. 【0012】 (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 with reference to Figures 1 to 6. 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 exemplifies 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. 【0013】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. The control device 180 may be configured, for example, by a processor, an LSI (Large Scale Integration), an FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated Circuit). 【0014】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. 【0015】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). 【0016】 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). 【0017】 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. 【0018】 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. 【0019】 The phosphor film 33 is composed of a yellow phosphor film that emits yellow light upon irradiation with excitation light Ex. In (a) of FIG. 4, the sign with brackets means that the component of the sign without brackets is located on the upper layer side thereof. That is, in (a) of FIG. 4, it shows that the reflective film 32 is disposed on the substrate 31, and the phosphor film 33 is located on the reflective film 32. 【0020】 The phosphor film 33 is composed of a yellow phosphor film that emits yellow light (light having a main wavelength of 560 to 590 nm) upon irradiation with excitation light. The above-described yellow light is an example of the color light output by the wavelength conversion element. The phosphor film 33 can be produced, for example, by mixing a powder of a ceramic phosphor into an adhesive (silicone resin), applying the mixture to a substrate, and curing it at a high temperature. Examples of the ceramic phosphor used for the phosphor film 33 include YAG phosphor and LAG phosphor, which are cerium-activated garnet structure phosphors. 【0021】 The phosphor wheel 30 emits emission light Ye from the phosphor film 33 while the position irradiated with the excitation light changes in the circumferential direction due to the rotation of the motor 34. In the present embodiment, the phosphor wheel 30 is used, but a fixed phosphor light source that does not rotate may also be used. 【0022】 Returning to FIG. 1, the dichroic mirror 40 has a coating property that transmits red component light R, green component light G, and blue component light B and reflects yellow component light Ye ０ of the emission light Ye １ among them. 【0023】 Referring to FIG. 1, first, the optical paths of the red component light R, the green component light G, and the blue component light B will be described. The emitted light (red component light R, green component light G, and blue component light B) from the RGB light source unit 10 is guided to the rod integrator 50 through the mirrors 111, diffusion plates 112, lenses 113, 114, diffusion plates 115, mirrors 116, lenses 117, dichroic mirror 40, lenses 118, mirrors 119, and lens 121. 【0024】 The mirrors 111, 114, and 116 are reflective mirrors that reflect the red component light R, the green component light G, and the blue component light B. 【0025】 Mirror 119 is a reflection mirror that reflects red component light R, green component light G, blue component light B, and yellow component light Ye. １ It is a reflection mirror that reflects red component light R, green component light G, blue component light B, and yellow component light Ye. 【0026】 Diffusion plates 112 and 115 are diffusion plates that adjust the divergence angles of red component light R, green component light G, and blue component light B. 【0027】 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, according to the diffusion angle characteristics of diffusion plate 112, the size and shape of the condensed spot formed on diffusion plate 115 are determined. 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 condensed spot formed on diffusion plate 115 is substantially imaged on the incident surface of rod integrator 50 via lenses 117, 118, and 121 (the diffusion plate 115 and the incident surface of rod integrator 50 are substantially conjugate). 【0028】 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 . 【0029】 Diffusion plate 122 is a diffusion plate that adjusts the divergence angle of excitation light Ex. 【0030】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. 【0031】 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). 【0032】 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). 【0033】 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. 【0034】 Light emitted from the rod integrator 50 passes through lenses 131, 132, and 133, enters a total internal reflection prism consisting of triangular prisms 141 and 142, and then enters the DMD 60. 【0035】 The DMD 60 modulates the 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-division manner. In detail, the DMD 60 is composed of multiple micro-mirrors, and these micro-mirrors are movable. Each micro-mirror basically corresponds to one pixel. The DMD 60 switches whether or not to reflect light towards the projection unit 70 by modulating the angle of each micro-mirror according to the video signal. 【0036】 Figure 6A is a schematic diagram showing an example of the subframe configuration of Embodiment 1. Figure 6B is a schematic diagram showing an example of the video frame configuration of Embodiment 1. Figures 6A and 6B show the correspondence between the display period of each color in the DMD 60 and the emission period of each color light source. In this embodiment, in the operation of the DMD 60, one video frame (for example, 1 / 60 sec) is composed of multiple subframes (Figure 6B), and one subframe is composed of color segments corresponding to the display of the colors R, Ye, G, Cy (cyan), and B (Figure 6A). The more subframes there are per video frame, the faster the color switching speed becomes, and thus the color breaking phenomenon can be reduced. To achieve a switching speed at which the color breaking phenomenon is almost invisible, it is desirable that the number of subframes be 16 or more (16 times faster). The configuration of the color segments in one subframe may be R, G, B, or R, G, B, Ye, and configurations with different numbers of colors may be mixed in each subframe. The order of the color segments may also be regular or irregular. Examples of the order of color segments will be discussed later with reference to Figures 10, 11, and 12. 【0037】The principle of image light generation in the DMD 60 will be explained with reference to Figures 6A, 6B, and 7A to 7E. Figure 7A is the spectral diagram of color segment R in Embodiment 1. Figure 7B is the spectral diagram of color segment Ye in Embodiment 1. Figure 7C is the spectral diagram of color segment G in Embodiment 1. Figure 7D is the spectral diagram of color segment Cy in Embodiment 1. Figure 7E is the spectral diagram of color segment B in Embodiment 1. 【0038】 The DMD60 performs gradation representation of each color corresponding to the color segments R, Ye, G, Cy, and B. During the period of color segment R, the red light source 10R and the excitation light source 20Ex are lit, that is, as shown in Figure 7A, the red component light R and the yellow component light Ye generated in response to the excitation light Ex are lit. １ This is modulated by the DMD 60. During the period of color segment Ye, the red light source 10R, the green light source 10G, and the excitation light source 20Ex are lit, that is, as shown in Figure 7B, the yellow component light Ye is generated in accordance with the red component light R, the green component light G, and the excitation light Ex. １ This is modulated by the DMD 60. During the period of color segment G, the green light source 10G and the excitation light source 20Ex are lit, that is, as shown in Figure 7C, the green component light G and the yellow component light Ye generated in response to the excitation light Ex are emitted. １ This is modulated by the DMD 60. During the color segment Cy, the green light source 10G, the blue light source 10B, and the excitation light source 20Ex are lit, that is, as shown in Figure 7D, the green component light G, the blue component light B, and the yellow component light Ye generated in response to the excitation light Ex. １ The light is modulated by the DMD 60. During the period of color segment B, the blue light source 10B is lit, that is, the blue component light B is modulated by the DMD 60 as shown in Figure 7E. The DMD 60 is an example of an optical modulation element. In other words, the red light source 10R, the green light source 10G, the blue light source 10B, and the excitation light source 20Ex are controlled by the control device 180 so that the light sources are lit in the subframes corresponding to their respective segment periods, and so that the light sources are turned off in the subframe periods that do not correspond to them. In other words, the control device 180 controls each light source by pulse drive. 【0039】 Returning to Figure 1, the image light generated by the DMD 60 is transmitted through the triangular prisms 141 and 142 and incident on the projection unit 70. The image light incident on the projection unit 70 is projected onto a screen (not shown) at an enlarged size. 【0040】 Here, the chromaticity in each color segment can be adjusted by adjusting the emission intensity (current supplied to the laser diode) of the excitation light source 20Ex using the control device 180. This will be explained with reference to Figures 8A and 8B. Figures 8A and 8B are chromaticity diagrams in Embodiment 1. Specifically, for example, during the period of color segment R, the red component light R and the yellow component light Ye １ The intensity ratio can be adjusted. As shown in Figure 8A, the chromaticity point R(x Ｒ , y Ｒ ) Color light and chromaticity point Ye(x Ｙｅ , y Ｙｅ As a result of mixing the colored light of ), the composite chromaticity point R'(x' Ｒ , y' Ｒ ) becomes colored light. Similarly, during the period of color segment G, green component light G and yellow component light Ye １ The intensity ratio can be adjusted. As shown in Figure 8A, the chromaticity point G(x Ｇ , y Ｇ ) Color light and chromaticity point Ye(x Ｙｅ , y Ｙｅ As a result of mixing the colored light of ), the composite chromaticity point G'(x' Ｇ , y' Ｇ The resulting color light is the composite chromaticity point R'(x'). As a result, the color gamut of the projection-type image display device 100 is the composite chromaticity point R'(x'). Ｒ , y' Ｒ ), composite chromaticity point G'(x' Ｇ , y' Ｇ ), chromaticity point B(x Ｂ , y Ｂ This forms a triangular region (Figure 8A) and covers the color gamut of Rec. 709. On the other hand, the light intensity of the excitation light source 20Ex can be freely adjusted within the specifications range of the laser diode, but it can also be turned off completely. In that case, the color gamut of the projection-type image display device 100 is as shown in Figure 8B, with chromaticity point R(x Ｒ , y Ｒ ), chromaticity point G(x Ｇ, y Ｇ ), chromaticity point B(x Ｂ , y Ｂ This forms a triangular region. 【0041】 In this way, the color gamut can be freely varied by adjusting the emission intensity of the excitation light source 20Ex using the control device 180. Regarding the video modes of the projection-type video display device 100, modes supporting Rec. 709 and modes supporting Rec. 2020 can be provided. However, the supported color gamut standards are not limited to these and can be freely set. Furthermore, the color gamut can be dynamically changed while analyzing the video frame according to the video frame. 【0042】 [Color Order of Image Light] The projection-type image display device 100 is a projection-type image display device using a single DMD 60 in a single-chip DLP system. In a single-chip DLP system projection-type image display device, when switching between red, green, and blue, the light sources for each color may be turned off to prevent color mixing. In this case, the brightness of the image light may decrease due to the turning off of the light sources for each color. A specific example will be explained with reference to Figure 9. Figure 9 is a schematic diagram to explain the dark time during color switching. 【0043】 Figure 9 shows the display period for each color in the DMD 60, the current supplied to the laser diode of each color light source, and the correspondence with the output light. The output light refers to the image light generated by modulation in the DMD 60. Hereinafter, the current supplied to the laser diode of the red light source 10R may be referred to as the R-LD current. The current supplied to the laser diode of the green light source 10G may be referred to as the G-LD current. The current supplied to the laser diode of the blue light source 10B may be referred to as the B-LD current. The current supplied to the laser diode of the excitation light source 20Ex may be referred to as the excitation LD current. The current supplied to the laser diode of each color light source is represented by a graph, which indicates whether the current is ON or OFF. When the current is ON, the light source is lit; when the current is OFF, the light source is turned off. The lighting and turning off of each color light source are controlled by the control device 180. 【0044】 In the example in Figure 9, each of the sections P1, P2, P3, and P4 that constitute one cycle is composed of a color segment. Each section corresponds to the display period of each color. Specifically, section P1 is composed of color segment R, section P2 is composed of color segment G, section P3 is composed of color segment Ye, and section P4 is composed of color segment B. Note that each of the sections may be a subframe. For example, one video frame may be composed of at least the subframes of sections P1, P2, P3, and P4. In this case, each subframe is composed of one color segment. Alternatively, each of the sections may be a color segment that constitutes a subframe. For example, one subframe may be composed of at least the color segments of sections P1, P2, P3, and P4. For the sake of explanation, each of the sections P1, P2, P3, and P4 is assumed to constitute one cycle. Therefore, the DMD 60 displays the color of section P4, and then displays the color of section P1 again. In this context, one period, which is comprised of each section, may be one video frame, one subframe, a part of one video frame, or a part of one subframe. 【0045】 Figure 9 shows a magnified view of the graphs of the current supplied to the laser diodes of each color light source at the transition between sections, along with the output light. In the example in Figure 9, when switching from section P1 to section P2, that is, when the color of the output light switches from red to green, the R-LD current and the excitation LD current switch from ON to OFF, resulting in a dark time D1. During the dark time, there is no output light from the DMD 60, so the screen (not shown) becomes dark. In other words, the brightness of the image light decreases due to the occurrence of the dark time. As shown in the graphs of the current supplied to the laser diodes of each color, a predetermined amount of time is required for each color light source to switch from ON to OFF, or from OFF to ON. Therefore, if one attempts to eliminate the dark time D1 when the color of the output light switches from red to green, there is a possibility that red and green light will mix. 【0046】Furthermore, in the example shown in Figure 9, a dark time D2 occurs when the interval switches from interval P3 to interval P4, that is, when the color of the output light switches from yellow to blue. Additionally, a dark time D3 occurs when the interval switches from interval P4 to interval P1, that is, when the color of the output light switches from blue to red. 【0047】 However, when the section switches from section P2 to section P3, that is, when the color of the output light switches from green to yellow, no dark time occurs. This is because the G-LD current remains ON when the section switches from section P2 to section P3; in other words, the green light source 10G remains lit. Thus, depending on the order of the output colors (the order of the color segments), it is possible to suppress the decrease in brightness of the image light without causing a dark time. 【0048】 Referring to Figures 10, 11, and 12, we will provide further specific examples to explain how to prevent the occurrence of dark time. Note that in the explanation of Figures 10, 11, and 12, sections that are the same as those explained with reference to Figure 9 may be omitted or simplified. 【0049】 Hereafter, yellow (Ye), cyan (Cy), and magenta (M) may be referred to as complementary colors. This is because yellow is the complementary color of blue, cyan is the complementary color of red, and magenta is the complementary color of green. Also, hereafter, red (R), green (G), and blue (B) may be referred to as primary colors. Yellow light is produced by mixing red light and green light. Cyan light is produced by mixing green light and blue light. Magenta light is produced by mixing blue light and red light. 【0050】 Figure 10 is a schematic diagram illustrating an example of the color sequence of the video light in Embodiment 1. In the example in Figure 10, sections P5, P6, P7, and P8 constitute one cycle. Under the control of the control device 180, section P5 is composed of color segment R, section P6 is composed of color segment Ye, section P7 is composed of color segment G, and section P8 is composed of color segment B. 【0051】In the example in Figure 10, no dark time occurs when the interval switches from interval P5 to interval P6, that is, when the color of the output light switches from red to yellow. This is because the R-LD current remains ON when the interval switches from interval P5 to interval P6, in other words, the red light source 10R remains lit. Similarly, no dark time occurs when the interval switches from interval P6 to interval P7, that is, when the color of the output light switches from yellow to green. This is because the G-LD current remains ON when the interval switches from interval P6 to interval P7, in other words, the green light source 10G remains lit. 【0052】 However, a dark time D4 occurs when the section switches from section P7 to section P8, that is, when the color of the output light switches from green to blue. Also, a dark time D5 occurs when the section switches from section P8 to section P5, that is, when the color of the output light switches from blue to red. 【0053】 Thus, when a complementary color containing the primary color is assigned to a section before or after a section to which the primary color is assigned by the control device 180, the occurrence of dark time between the section to which the primary color is assigned and the section to which the complementary color is assigned can be suppressed. In other words, when a primary color included in the complementary color is assigned to a section before or after a section to which the complementary color is assigned, the occurrence of dark time between the section to which the primary color is assigned and the section to which the complementary color is assigned can be suppressed. This suppresses the decrease in brightness of the image light. In the example in Figure 10, the number of dark times occurring in one cycle composed of multiple sections is reduced compared to the example in Figure 9. In other words, when the order of the colors of the image light of the projection-type image display device 100 is as shown in Figure 10, the decrease in brightness of the image light is suppressed compared to when the order of the colors of the image light is as shown in Figure 9. 【0054】Figure 11 is a schematic diagram illustrating an example of the color sequence of the video light in Embodiment 1. In the example in Figure 11, sections P9, P10, P11, P12, and P13 constitute one cycle. Under the control of the control device 180, section P9 is composed of color segment R, section P10 of color segment Ye, section P11 of color segment G, section P12 of color segment Cy, and section P13 of color segment B. In the example in Figure 11, cyan is added to the color of the video light generated by the DMD 60 compared to the example in Figure 10. 【0055】 In the example in Figure 11, no dark time occurs when the interval switches from interval P9 to interval P10, that is, when the color of the output light switches from red to yellow. This is because the R-LD current remains ON when the interval switches from interval P5 to interval P6, in other words, the red light source 10R remains lit. Similarly, no dark time occurs when the interval switches from interval P10 to interval P11, that is, when the color of the output light switches from yellow to green. This is because the G-LD current remains ON when the interval switches from interval P10 to interval P11, in other words, the green light source 10G remains lit. As in the example in Figure 10, when the order of the video light is red, yellow, and green, no dark time occurs when switching from red to yellow and when switching from yellow to green. 【0056】 Furthermore, in the example shown in Figure 11, no dark time occurs when the interval switches from interval P11 to interval P12, that is, when the color of the output light switches from green to cyan. This is because the G-LD current remains ON when the interval switches from interval P11 to interval P12, in other words, the green light source 10G remains lit. Similarly, no dark time occurs when the interval switches from interval P12 to interval P13, that is, when the color of the output light switches from cyan to blue. This is because the B-LD current remains ON when the interval switches from interval P12 to interval P13, in other words, the blue light source 10B remains lit. 【0057】However, when the interval switches from interval P13 to interval P9, that is, when the color of the output light switches from blue to red, a dark time D6 occurs. 【0058】 Thus, when the video light generated by the DMD 60 includes cyan, which is its complementary color, and the section assigned to cyan is after (or before) the section assigned to green, no dark time occurs when switching between cyan and green. This is because the green light source 10G remains lit during the section switch. Also, when the section assigned to cyan is before (or after) the section assigned to blue, no dark time occurs when switching between cyan and blue. This is because the blue light source 10B remains lit during the section switch. In this way, by including cyan as a complementary color in addition to yellow, and by setting the order of each color to a predetermined order (for example, the order shown in Figure 11), the occurrence of dark time can be further suppressed compared to, for example, the case where the video light colors are only red, green, blue, and yellow. Furthermore, this makes it possible to suppress the decrease in the brightness of the video light. 【0059】 Figure 12 is a schematic diagram illustrating an example of the color sequence of the video light in Embodiment 1. In the example in Figure 12, sections P14, P15, P16, P17, P18, and P19 constitute one cycle. Under the control of the control device 180, section P14 is composed of color segment R, section P15 of color segment Ye, section P16 of color segment G, section P17 of color segment Cy, section P18 of color segment B, and section P19 of color segment M. In the example in Figure 12, magenta is added to the colors of the video light generated by the DMD 60 compared to the example in Figure 11. 【0060】 Similar to the example in Figure 11, no dark time occurs when the interval switches from interval P14 to interval P15, from interval P15 to interval P16, from interval P16 to interval P17, and from interval P17 to interval P18. In other words, no dark time occurs when the output light switches in the order of red, yellow, green, cyan, and blue. 【0061】In the example in Figure 11, the output light switches from blue to red, but in the example in Figure 12, the output light switches from blue to magenta and from magenta to red. When the section switches from section P18 to section P19, that is, when the color of the output light switches from blue to magenta, no dark time occurs. This is because the B-LD current remains ON when the section switches from section P18 to section P19, in other words, the blue light source 10B remains lit. Also, when the section switches from section P19 to section P14, that is, when the color of the output light switches from magenta to red, no dark time occurs. This is because the R-LD current remains ON when the section switches from section P19 to section P14, in other words, the red light source 10R remains lit. 【0062】 Thus, when the video light generated by the DMD 60 includes magenta, which is a complementary color, and the section to which magenta is assigned is after (or before) the section to which blue is assigned, no dark time occurs when switching between magenta and blue. This is because the blue light source 10B remains lit during the section switch. Also, when the section to which magenta is assigned is before (or after) the section to which red is assigned, no dark time occurs when switching between magenta and red. This is because the red light source 10R remains lit during the section switch. In this way, by including magenta as a complementary color in addition to yellow and cyan, and by setting the order of each color to a predetermined order (for example, the order shown in Figure 12), the occurrence of dark time can be further suppressed compared to, for example, when the colors of the video light are only red, green, blue, yellow, and cyan. Furthermore, this makes it possible to suppress the decrease in brightness of the video light. 【0063】As explained above with reference to Figures 10, 11, and 12, each of the multiple sections constituting one cycle may be assigned a primary color containing one of red, green, and blue light, and a complementary color containing two of red, green, and blue light. In this case, the primary color included in the complementary color may be assigned to a second section before or after the first section to which the complementary color is assigned. Note that the terms "first," "second," and later "third" and "fourth" are used merely to distinguish them from other elements and are not intended to be interpreted restrictively. The control device 180 may control the lighting (ON) and turning off (OFF) of each light source to output video light of the color assigned to each section. For example, as shown in Figure 12, if the primary color red is assigned to section P14, which precedes section P15 where the complementary color yellow is assigned, and the primary color green is assigned to section P16, which follows section P15, then it is possible to prevent dark time from occurring at the transitions between sections P14, P15, and P16. 【0064】 Furthermore, the light source corresponding to the primary color of the second section may remain lit between the first section before or after the second section and the second section. For example, the light source corresponding to the red color assigned to section P14 in Figure 12, i.e., the red light source 10R, may remain lit between section P14 and section P15, i.e., when switching between section P14 and section P15. 【0065】Furthermore, among multiple intervals, a complementary color may be assigned to the third interval, and a primary color included in that complementary color may be assigned to the fourth interval following the third interval. The light source corresponding to the primary color not assigned to the fourth interval among the two primary colors included in the complementary color assigned to the third interval may be temporarily turned off when switching from the third interval to the fourth interval. Here, we will explain using the example where the third interval is interval P12 shown in Figure 11, and the fourth interval is interval P13 shown in Figure 12. Cyan is assigned to interval P12, and blue, one of the green and blue included in cyan, is assigned to interval P13. The green light source 10G corresponding to the primary color not assigned to interval P13 among the green and blue included in cyan assigned to interval P12, i.e., green, is temporarily turned off when switching from interval P12 to interval P13. As a result, the color of the output light switches from cyan to blue without the occurrence of dark time. It should be noted that the light source does not turn off permanently, but rather turns on periodically, hence the expression "temporarily turns off." 【0066】 In this way, by defining the order of the output light colors such that the colors before and after a primary color are complementary colors including that primary color, the occurrence of dark time can be prevented and the decrease in brightness can be suppressed. The order of the colors of the video light generated by the DMD 60 will be explained with reference to Figure 13. Figure 13 is a chromaticity diagram for illustrating an example of the order of the colors of the video light in Embodiment 1. The order of the output colors is preferably in the direction indicated by the arrows in Figure 13, that is, in a clockwise or counterclockwise direction. Specifically, the order of the output colors is preferably red, yellow, green, cyan, blue, magenta, or red, magenta, blue, cyan, green, yellow. For the sake of explanation, the first color in the order of colors is shown as red, but it is not limited to this. 【0067】Furthermore, in order to prevent the occurrence of dark time and suppress the decrease in brightness of the image light by setting the output order of each primary color and each complementary color to a predetermined order, yellow light (fluorescent light) from the excitation light is not essential. This is because yellow light can be generated from red light and green light. However, as explained with reference to Figures 8A and 8B, if the projection-type image display device 100 is equipped with an excitation light source 20Ex (excitation light source unit 20), the chromaticity in each color segment can be adjusted by adjusting the emission intensity of the excitation light source 20Ex (current supplied to the laser diode) using the control device 180. 【0068】 Furthermore, the colors assigned to multiple sections are not limited to primary or complementary colors; white light, including red, green, and blue light, may also be assigned. Outputting white light as image light can improve the brightness of a screen (not shown). This is because white light contains all colors of light, in other words, all of red, green, and blue light, and therefore outputs more light compared to other colors of light. 【0069】 (Summary of Embodiments) The following technologies are disclosed based on the above description of embodiments. The components etc. in the above embodiments are examples, but are not limited to these. 【0070】 (Technology 1) A control method for a projection-type image display device (e.g., projection-type image display device 100) comprising a light source that emits red light (e.g., red light source 10R), a light source that emits green light (e.g., green light source 10G), and a light source that emits blue light (e.g., blue light source 10B), wherein each of a plurality of sections constituting one cycle (e.g., section P5, section P6, etc.) is assigned a primary color including one of red light, green light, and blue light, and at least one of a complementary color including two of red light, green light, and blue light, or white including all of red light, green light, and blue light, and the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned, and the on / off of each light source is controlled to output image light of the color assigned to each of the plurality of sections. 【0071】As a result, the control method for projection-type image display devices can prevent the occurrence of dark time, for example, when switching between consecutive subframes or color segments. This also allows the control method for projection-type image display devices to suppress a decrease in the brightness of the image light. 【0072】 (Technical 2) In the control method for projection-type image display device described in Technical 1, the light source corresponding to the primary color of the second section may remain lit between the first section and the second section. 【0073】 As a result, the control method for projection-type image display devices can, for example, keep the red, green, or blue light source lit when switching between consecutive subframes or color segments, thereby preventing the occurrence of dark time. 【0074】 (Technical 3) In the control method for a projection-type image display device described in Technical 1 or 2, the primary colors included in the complementary color are assigned to a fourth section following a third section to which the complementary color is assigned, and the light source corresponding to the primary color among the two primary colors included in the complementary color assigned to the third section that is not assigned to the fourth section may be temporarily turned off when switching from the third section to the fourth section. 【0075】 This allows the control method for projection-type image display devices to switch the color of the image light from complementary colors to primary colors without causing dark time. 【0076】 (Technology 4) The projection-type image display device comprises a light source that emits red light, a light source that emits green light, a light source that emits blue light, and a control device. The control device controls the lighting and extinguishing of each light source to output image light of a color assigned to each of a plurality of sections that constitute one cycle. Each of the plurality of sections is assigned a primary color that includes one of red light, green light, and blue light, and at least one of a complementary color that includes two of red light, green light, and blue light, or white that includes all of red light, green light, and blue light. The primary color included in the complementary color is assigned to a second section that is either before or after a first section to which the complementary color is assigned. 【0077】 As a result, the projection-type image display device can achieve the same effect as in Technology 1. 【0078】Although various embodiments have been described above with reference to the attached drawings, this disclosure is not limited to such examples. It will be 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 will also be understood to fall within the technical scope of this disclosure. Furthermore, the components of the various embodiments described above can be combined arbitrarily without departing from the spirit of the invention. 【0079】 The technology disclosed herein is useful as a control method for projection-type image display devices and as a projection-type image display device itself. 【0080】 10 RGB light source unit 10R Red light source 10G Green light source 10B Blue light source 20 Excitation light source unit 30 Phosphor wheel 40 Dichroic mirror 50 Rod integrator 60 DMD 70 Projection unit 100 Projection type image display device 150 Light source device 180 Control device

Claims

1. A control method for a projection-type image display device comprising a light source emitting red light, a light source emitting green light, and a light source emitting blue light, wherein each of a plurality of sections constituting one cycle is assigned a primary color including one of the red light, the green light, and the blue light, and at least one of a complementary color including two of the red light, the green light, and the blue light, or white including all of the red light, the green light, and the blue light, and the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned, and the on / off of each of the light sources is controlled to output image light of the color assigned to each of the plurality of sections.

2. The control method for a projection-type image display device according to claim 1, wherein the light source corresponding to the primary color of the second section remains lit between the first section and the second section.

3. A control method for a projection-type image display device according to claim 2, wherein the primary color included in the complementary color is assigned to a fourth section following a third section to which the complementary color is assigned, and the light source corresponding to the primary color among the two primary colors included in the complementary color assigned to the third section that is not assigned to the fourth section is temporarily turned off when switching from the third section to the fourth section.

4. A projection-type image display device comprising: a light source that emits red light; a light source that emits green light; a light source that emits blue light; and a control device, wherein the control device controls the lighting and extinguishing of each of the light sources to output image light of a color assigned to each of a plurality of sections constituting one cycle; and each of the plurality of sections is assigned by the control device at least one of a primary color including one of the red light, the green light, and the blue light, and a complementary color including two of the red light, the green light, and the blue light, or white including all of the red light, the green light, and the blue light; and the primary color included in the complementary color is assigned to a second section before or after a first section to which the complementary color is assigned.

5. The projection-type image display device according to claim 4, wherein the light source corresponding to the primary color of the second section remains lit between the first section and the second section.

6. The projection-type image display device according to claim 5, wherein the primary color included in the complementary color is assigned to a fourth section following a third section to which the complementary color is assigned, and the light source corresponding to the primary color among the two primary colors included in the complementary color assigned to the third section that is not assigned to the fourth section is temporarily turned off when switching from the third section to the fourth section.

Images