Projector device, light source device, and light source driving method

Abstract

A projector apparatus or a light source apparatus comprising: a first light source which outputs a first light source light; a second light source of which the wavelength of primary color light is different from the wavelength of primary color light of the first light source, and which outputs a second light source light; a phase modulating element for converting the distribution of the amount of the second light source light; an amplitude modulating element on which the first light source light and the second light source light that has passed through the phase modulating element are both incident, and which performs amplitude modulation with respect to the incident light; and a signal processing unit. The signal processing unit generates an amplitude-modulation drive signal with respect to the amplitude modulating element on the basis of a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulating element.

Description

Technical Field

[0001] The present technology relates to a projector device, a light source device provided in the projector device and the like, and a light source driving method.

Background Art

[0002] There is known a technique of reproducing an image having a desired light intensity distribution by performing amplitude modulation (spatial light intensity modulation) on incident light using a spatial light modulator (SLM) such as a liquid crystal element or a DMD (Digital Micromirror Device).

[0003] In such a technical field, Patent Document 1 below discloses a technique for reducing color unevenness that occurs when two projectors are stacked and projected.

Prior Art Document

Patent Document

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, there is also known a technique of projecting a desired reproduced image by performing spatial light phase modulation (simply referred to as "phase modulation" in the present disclosure) on incident light. When performing amplitude modulation, a part of the incident light is attenuated or blocked when reproducing a desired light intensity distribution, but in the case of phase modulation, it is possible to reproduce a desired light intensity distribution without performing light attenuation or light blocking.

[0006] In the present disclosure, when considering a projector device that uses a plurality of light sources and combines phase modulation and amplitude modulation, an object is to reduce the occurrence of color unevenness.

Means for Solving the Problems

[0007] The projector device according to the present technology includes a first light source that outputs first light source light, a second light source that outputs second light source light whose primary color light wavelength is different from the primary color light wavelength of the first light source, an amplitude modulation element into which both the first light source light and the second light source light are incident and that performs amplitude modulation on the incident light, and a signal processing unit that generates an amplitude modulation drive signal for the amplitude modulation element based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element. The light source device according to the present technology also has a similar configuration. For example, assume a case where the wavelengths of R light, G light, and B light from the first light source are different from the wavelengths of R light, G light, and B light from the second light source due to differences in the light sources themselves. For example, the wavelength of R light from the first light source is different from the wavelength of R light from the second light source. The wavelengths of G light and B light are also different between the first light source and the second light source. A case where some of the wavelengths of R light, G light, and B light are different between the first light source and the second light source is also assumed. In these cases, if an amplitude modulation drive signal is generated assuming a fixed gamma curve corresponding to the first light source or a fixed gamma curve corresponding to the second light source in the amplitude modulation element, the amplitude modulation of the originally assumed gradation cannot be achieved, and color unevenness occurs. Therefore, a gamma curve corresponding to the ratio of the first light source light and the second light source light is calculated, and an amplitude modulation drive signal is generated based on it.

Brief Description of the Drawings

[0008]

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MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, the embodiments will be described in the following order. <1. Amplitude Modulation and Phase Modulation in the Projector Device> <2. Configuration of the Projector Device in the Embodiment> <3. Generation and Countermeasure of Color Unevenness> <4. Signal Processing in the First Embodiment> <5. Signal Processing in the Second Embodiment> <6. Signal Processing in the Third Embodiment> <7. Summary and Modification Example>

[0010] <1. Amplitude Modulation and Phase Modulation in the Projector Device> For understanding the embodiment, first, amplitude modulation and phase modulation in the projector device will be described.

[0011] FIG. 1 simply shows the configuration of a projector (or a light source device) using an amplitude modulation element 5. Illumination light 100 from the light source 111 is incident on the amplitude modulation element 5 via an optical system (not shown). The illumination light 100 is light having a uniform brightness distribution in the in-plane region as schematically shown, and this is split into R light (red light), G light (green light), and B light (blue light) temporally or spatially by the optical system and then incident on the amplitude modulation element 5. In the amplitude modulation element 5, light that forms an image as a projected video is emitted by modulating the light intensity for each pixel of the incident light. For the sake of distinction in the description, the projector of this method will be referred to as an amplitude modulation type projector.

[0012] Figure 2 simply shows the configuration of a projector (or a light source device) using the phase modulation element 3 and the amplitude modulation element 5. The illumination light 101 from the light source 112 is light having a uniform brightness distribution in the in-plane region as schematically shown. This illumination light 101 is phase-modulated in the phase modulation element 3 according to the phase modulation drive signal Sd2. That is, illumination light 102 having an arbitrary distribution is generated using the principle of diffraction or refraction of light. For example, it is also possible to obtain a light quantity distribution in which the light quantity rises partially in the in-plane region.

[0013] Figure 3 schematically shows the relationship between each ray of the illumination light 101 incident on the phase modulation surface Sm of the phase modulation element 3, the wavefront of the phase distribution in the phase modulation element 3, each ray after phase modulation, and the light intensity distribution formed on the virtual projection surface Sp by each ray after phase modulation. The wavefront of the phase distribution corresponding to the phase modulation drive signal Sd2 in the phase modulation element 3 draws a smooth curve as shown in the figure, for example. By the spatial light phase modulation in the phase modulation element 3, each incident ray is refracted so as to travel in the normal direction of the wavefront of the phase distribution. Due to this refraction, on the projection surface Sp, a portion where the ray density increases and a portion where the ray density becomes sparse are formed, and thereby, a light intensity distribution is formed on the projection surface Sp.

[0014] The illumination light 102 phase-modulated in this way by the phase modulation element 3 in FIG. 2 is incident on the amplitude modulation element 5 and amplitude-modulated according to the amplitude modulation drive signal Sd1 based on the video signal, as in the case of FIG. 1, so that light forming an image of the projected video is emitted. For the sake of distinction in explanation, the projector of the method in FIG. 2 will be referred to as a phase / amplitude modulation type projector.

[0015] In the case of an amplitude modulation type projector as in FIG. 1, unnecessary light is discarded by the amplitude modulation element 5. However, in the case of a phase / amplitude modulation type projector as in FIG. 2, by generating a light quantity distribution corresponding to the input video signal with the phase modulation element 3, it is possible to reduce the amount of light discarded by the subsequent amplitude modulation element 5. Therefore, the energy efficiency can be improved. Furthermore, in the phase / amplitude modulation type projector, since it is possible to boost the light quantity by collecting light from a dark area to a bright area in the plane, the dynamic range of the projected video can be expanded.

[0016] <2. Configuration of the Projector Device of the Embodiment> Based on the configurations of FIGS. 1 and 2 above, the configuration of the projector device (or light source device) of the embodiment will be described. The projector device of the embodiment can be called a hybrid type projector that combines the amplitude modulation type projector of FIG. 1 and the phase / amplitude modulation type projector of FIG. 2. The outline of the configuration as a hybrid type projector (or light source device) of the embodiment is shown in FIG. 4.

[0017] As shown in the figure, the hybrid type projector of the embodiment has a first light source 1 (hereinafter referred to as "light source 1") and a second light source 2 (hereinafter referred to as "light source 2"). Light source 1 is a light source corresponding to light source 111 in the configuration of the amplitude modulation type projector of FIG. 1, and for example, a phosphor light source is used. The illumination light from light source 1 will be referred to as first light source light 104. The light source 2 corresponds to the light source 112 in the configuration of the phase / amplitude modulation type projector of FIG. 2, and for example, a laser light source is used. The illumination light from the light source 2 is distinguished before and after the phase modulation element 3, and is referred to as the second light source light 105 or the second light source light 106. Note that the light sources 1 and 2 are not limited to a phosphor light source or a laser light emitting element, and other light emitting elements such as an LED (Light Emitting Diode) can also be used.

[0018] The first light source light 104 from the light source 1 is incident on the amplitude modulation element 5 via the multiplexing optical system 4. The amplitude modulation element 5 is formed by a reflective or transmissive liquid crystal panel or a DMD (DMD that performs amplitude modulation).

[0019] On the other hand, the second light source light 105 from the light source 2 is incident on the phase modulation element 3. This phase modulation element 3 is composed of a reflective or transmissive liquid crystal panel or a DMD. However, the DMD in this case is not a general DMD in which each pixel tilts to bend light, but a phase modulation DMD in which each pixel shifts in the normal direction to change the phase amount of light. And in the phase modulation element 3, as described in FIG. 3, the incident light is phase-modulated and output to have an arbitrary distribution using the principle of diffraction or refraction of light. Therefore, the second light source light 106 emitted from the phase modulation element 3 is the light obtained by phase-modulating the second light source light 105.

[0020] The second light source light 106 is incident on the amplitude modulation element 5 via the multiplexing optical system 4. Therefore, the first light source light 104 and the second light source light 106 are multiplexed and incident on the amplitude modulation element 5. In the amplitude modulation element 5, the light intensity of each pixel is modulated by the amplitude modulation drive signal Sd1 based on the video signal, and the projection video light 107 is emitted. Thereby, a projection video based on the video signal is displayed on a screen surface (not shown).

[0021] As shown in FIG. 4, in the hybrid projector of the embodiment, it has the configuration of an amplitude modulation type projector by the light source 1 and the amplitude modulation element 5, and the configuration of a phase / amplitude modulation type projector by the light source 2, the phase modulation element 3, and the amplitude modulation element 5.

[0022] And it includes a signal processing unit 10 that generates a phase modulation drive signal Sd2 supplied to the phase modulation element 3 and an amplitude modulation drive signal Sd1 supplied to the amplitude modulation element 5. The signal processing unit 10 can be configured to include a microcomputer having, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc.

[0023] The signal processing unit 10 calculates the phase distribution of the phase modulation element 3 based on the input video signal D. Then the signal processing unit 10 supplies the phase modulation drive signal Sd2 to the phase modulation element 3 according to the calculated phase distribution to control the phase modulation operation. Specifically, phase modulation is performed so that the light density in the low-luminance region on the video plane projected by the video signal D is low and the light density in the high-luminance region is high. Note that the video signal D is, for example, an RGB signal of an R signal Dr, a G signal Dg, and a B signal Db.

[0024] Also, the signal processing unit 10 generates an amplitude modulation drive signal Sd1 that controls the amplitude modulation of each pixel of the amplitude modulation element 5 based on the input video signal D and supplies it to the amplitude modulation element 5. As a result, the amplitude modulation element 5 performs amplitude modulation according to the luminance specified by the video signal for each pixel, and projection video light 107 corresponding to the video signal D is generated.

[0025] The above FIG. 4 is simplified for comparison with FIGS. 1 and 2, and a more detailed configuration of the projector of the embodiment is shown in FIG. 5.

[0026] For example, the light source 1 as a phosphor light source and the first illumination optical system 8 are formed. The light from the light source 1 is white light, which is split into R light, G light, and B light by the first illumination optical system 8 and guided to the multiplexing optical system 4.

[0027] For example, the light source 2 and the second illumination optical system 6 are formed by a laser light source. The light from the light source 2 is white light, which is split into R light, G light, and B light by the second illumination optical system 6 and guided to the phase modulation element 3.

[0028] The phase modulation element 3 is provided with a phase modulation element 3R corresponding to R light, a phase modulation element 3G corresponding to G light, and a phase modulation element 3B corresponding to B light. The R light from the second illumination optical system 6 is phase-modulated by the phase modulation element 3R, the G light is phase-modulated by the phase modulation element 3G, and the B light is phase-modulated by the phase modulation element 3B. This phase-modulated R light, G light, and B light correspond to the above-mentioned second light source light 106 and are incident on the multiplexing optical system 4.

[0029] In the multiplexing optical system 4, the R lights, G lights, and B lights of the first light source light 104 and the second light source light 106 are multiplexed and guided to the amplitude modulation elements 5 respectively. The amplitude modulation element 5 is provided with an amplitude modulation element 5R corresponding to R light, an amplitude modulation element 5G corresponding to G light, and an amplitude modulation element 5B corresponding to B light. The multiplexed R light is amplitude-modulated by the amplitude modulation element 5R, the multiplexed G light is amplitude-modulated by the amplitude modulation element 5G, and the multiplexed B light is amplitude-modulated by the amplitude modulation element 5B. Then, the amplitude-modulated R light, G light, and B light are synthesized into projection video light 107 and projected by the projection lens 9.

[0030] In this Figure 5, the image creation signal processing unit 11 and the phase pattern generation unit 12 shown by the broken lines are processing functions realized by software in the signal processing unit 10 shown in Figure 4. The image creation signal processing unit 11 generates an amplitude modulation drive signal Sd1 for each of the amplitude modulation elements 5R, 5G, and 5B based on the input video signal D(Dr, Dg, Db).

[0031] Also, based on the input video signal D (Dr, Dg, Db), the image creation signal processing unit 11 generates a phase distribution to be realized by the phase modulation elements 3R, 3G, and 3B. The phase pattern generation unit 12 generates phase pattern signals PHr, PHg, and PHb for actually performing phase modulation by the phase modulation elements 3R, 3G, and 3B respectively from the phase distribution based on the video signals Dr, Dg, and Db, and outputs these as phase modulation drive signals Sd2 to the phase modulation elements 3R, 3G, and 3B.

[0032] Note that specific processing examples of the signal processing unit 10 including the image creation signal processing unit 11 and the phase pattern generation unit 12 will be described later as the signal processing of the first, second, and third embodiments. With the configuration of FIG. 5 above, a hybrid projector using each primary color light of R light, G light, and B light is realized.

[0033] <3. Generation and Countermeasures of Color Mura> Here, the color mura in the hybrid projector as described above will be explained. As an example, consider the case where the input video signal D is a signal of a grayscale gradation video. FIGS. 6A and 6B show that the first light source light 104 and the phase-modulated second light source light 106 are incident on the amplitude modulation element 5.

[0034] In the following embodiments, on the premise of using a reflective liquid crystal panel or a DMD as the amplitude modulation element 5, an example of controlling the reflectivity by the amplitude modulation element 5 will be described. However, the following description part regarding the reflectivity can be rephrased as the transmittance when using a transmissive liquid crystal panel.

[0035] In the case of the hybrid projector as shown in FIG. 4, basically, as shown in FIG. 6B, a light amount distribution corresponding to the gradation is generated by the second light source light 106 that has passed through the phase modulation element 3, and it is desirable to set the transmittance or reflectivity to the maximum in the amplitude modulation element 5 so as not to discard the light. Setting the reflectivity to the maximum with the amplitude modulation element 5 means making the reflectivity distribution 110 of the amplitude modulation element 5 controlled by the amplitude modulation drive signal Sd1 uniform in the plane and maximum as shown in the figure. As a result, the projected video light 107 becomes light that projects a gradation as shown in the figure.

[0036] On the other hand, as shown in FIG. 6A, it is also conceivable that the second light source light 106 has a uniform light amount distribution and a gradation-like reflectivity distribution is generated by the amplitude modulation element 5. Due to the characteristics of the phase modulation element 3, it is difficult to generate a light amount distribution having a spatial resolution as high as that of the pixels of the amplitude modulation element 5 in the second light source light 106. On the other hand, in the case of the amplitude modulation element 5, the incident light can be modulated for each pixel. For example, as shown in FIG. 6C, consider a case where there is a bright region 131 (low spatial frequency) in a dark background 130 and a narrow gradation-like region 132 (high spatial frequency) is present therein. In this case, the bright region 131 in the dark background 130 can be realized by the light amount of the second light source light 106, and the narrow region 132 therein can be realized by the amplitude modulation element 5. Taking the narrow region 132 in such a case as an example, in order to consider color unevenness and its countermeasures in a hybrid projector, for simplicity, the case of FIG. 6A where the entire screen is gradation and it is realized by the reflectivity of the amplitude modulation element is used in the following explanation.

[0037] In the hybrid projector having the configurations shown in FIGS. 4 and 5 above, if the wavelengths of the R light, G light, and B light from the light source 1 and the light source 2 and the white points of the light source 1 and the light source 2 are the same, even when the first light source light 104 and the second light source light 106 after phase modulation are added together, the white point in the in-plane region does not change. Therefore, if the reflectivities of the RGB colors of each pixel are the same with the amplitude modulation element 5, the white point of the finally generated image also does not change, and color unevenness does not occur. In the present disclosure, the “wavelength” of primary color light such as R light, G light, and B light means the dominant wavelength, i.e., the main wavelength, in the case of a light source having a certain wavelength width for one color.

[0038] On the other hand, when using liquid crystal as the amplitude modulation element with different wavelengths for each of the R, G, and B lights from light source 1 and light source 2, color unevenness occurs even when the white points are the same. This is because even for the same color, if the wavelengths are different, the characteristics of the reflectance with respect to the voltage of the liquid crystal (hereinafter referred to as the VR curve) are different.

[0039] For example, for light source 1 and light source 2, the wavelengths of each color are different as follows. · Wavelength of B light... Light source 1: 445 nm, Light source 2: 462 nm · Wavelength of G light... Light source 1: 555 nm, Light source 2: 520 nm · Wavelength of R light... Light source 1: 610 nm, Light source 2: 635 nm

[0040] In this case, each VR curve is as shown in FIG. 7. In FIG. 7, the R light (R1), G light (G1), and B light (B1) of light source 1 are shown by dashed lines, and the R light (R2), G light (G2), and B light (B2) of light source 2 are shown by solid lines.

[0041] Here, considering the case of the amplitude modulation type projector as shown in FIG. 1, for each of the R, G, and B lights, the VR curve is measured, and from the relationship between the reflectance with respect to the gradation (gamma curve, for example, reflectance = gradation to the power of 2.2), the relationship between the voltage with respect to the gradation (gamma table) is determined by adjustment.

[0042] However, in the case of the hybrid type projector of the present embodiment, the light quantity distribution of the second light source light 106 is different for each frame of the video. When the light quantity distribution of the second light source light 106 is not uniform in a certain frame, at the stage of the amplitude modulation element 5, the ratio of the light quantities of the first light source light 104 and the second light source light 106 is different for each pixel.

[0043] That is, in the phase modulation element 3, since light is moved to other regions by phase modulation, as the distribution of the second light source light 106, there are pixels where almost no light from the light source 2 exists and pixels where light is concentrated. In pixels where almost no light from the light source 2 exists, the VR curve of the amplitude modulation element 5 becomes almost equal to the VR curve when only the light source 1 is lit. On the other hand, for the pixels in the region where the light from the second light source 106 is extremely concentrated and the light amount surges, the pixels receive much more light from the second light source than from the first light source. In this case, since the light from the first light source can be ignored, the VR curve of those pixels is almost equal to the VR curve when only the second light source is lit. That is, the actual VR curve varies for each frame and each pixel, and changes according to the ratio of the light from the first light source and the light from the second light source. Therefore, the VR curve is a curve between the VR curve when only the first light source is lit and the VR curve when only the second light source is lit.

[0044] When the VR curve changes, the gamma curve also changes. This is shown in FIG. 8. FIG. 8 shows the gamma curve C1 of a certain color of the amplitude modulation element 5 when only the first light source is lit, and the gamma curve C2 of a certain color of the amplitude modulation element 5 when only the second light source is lit. Also shown is an intermediate gamma curve C3.

[0045] Now, in a certain pixel, even if an amplitude modulation drive signal with a certain voltage value is given to achieve a certain gradation, the reflectance of that pixel will differ depending on the gamma curves C1, C2, and C3. Therefore, even if the same gradation control is performed for each pixel of the amplitude modulation drive signal, the reflectance of each pixel will differ depending on the light amount ratio of the first light source light 104 and the second light source light 106 in each pixel, resulting in color unevenness.

[0046] When the white point at the highest gradation is made to match for both the first light source and the second light source, the white point does not change at the highest gradation regardless of the light amount of the second light source. However, at gradations below the highest gradation, color unevenness occurs depending on the light amount of the light from the second light source due to the reasons described above.

[0047] A specific example of color unevenness is shown in FIG. 9. FIG. 9 shows the case where the first light source light 104 and the second light source light 106 are combined and incident on the amplitude modulation element 5 in which the reflectance of each pixel is controlled by the reflectance distribution 110 by the amplitude modulation drive signal Sd1.

[0048] Note that in this case, the video is such that the rectangle located in the center has high brightness and the surrounding area has low brightness. Then, by the phase modulation element 3, the second light source light 106 is phase-modulated so that the center of the rectangle has high brightness. However, since it is difficult to control the light amount with high spatial resolution depending on the phase modulation, the second light source light 106 has a light amount distribution where the edges of the central region are blurred.

[0049] In this case, as the amplitude modulation drive signal, as shown in the figure, it is a signal that performs control such that the reflectance at the center is lower than that at the edge even within the high-brightness region. As a result, the video by the projection video light 107 is a video where the central rectangle has high brightness. However, within the central region of the rectangle, the light amount ratio of the first light source light 104 and the second light source light 106 incident on each pixel is different. Therefore, as schematically shown in the figure, color unevenness Z occurs.

[0050] Fig. 10 shows the difference in light amount distribution in detail. Each distribution is shown corresponding to the A-A cross section in the horizontal direction of the projection video light 107. The first light source light 104 has a uniform light amount distribution in the plane, and the light amount distribution is flat even when viewed in the A-A cross section. The second light source light 106 is assumed to have the light amount distribution in the A-A cross section as shown in the figure by being phase-modulated according to the video. The total light amount distribution is the distribution of the light incident on the amplitude modulation element 5 and is the sum of the first light source light 104 and the second light source light 106.

[0051] By controlling the amplitude modulation element 5 with the reflectance distribution 110 as shown in the lowermost stage for the incident light indicated by this total light amount distribution, the light amount distribution of the projection video light 107 becomes the light amount distribution corresponding to the video as shown by the final light amount distribution. However, since the second light source light 106 has a light amount distribution where the center bulges, the light amount ratio of the first light source light 104 and the second light source light 106 is also different for each pixel within the central region of the rectangle. Therefore, color unevenness Z occurs.

[0052] In this embodiment, a process for reducing or eliminating such color unevenness is performed. FIG. 11 shows gamma curves C1 and C2 in the same manner as FIG. 8. In this embodiment, as shown in FIG. 11, from the gamma curve C1 of the amplitude modulation element 5 when only the light source 1 measured in advance is lit and the gamma curve C2 of the amplitude modulation element 5 when only the light source 2 is lit, a gamma curve Cm is calculated according to the light quantity ratio when both light sources 1 and 2 are lit.

[0053] This gamma curve Cm changes according to the light quantity ratio between the light source 1 and the light source 2. That is, the higher the light quantity ratio of the light source 1, the closer it is to the gamma curve C1, and the higher the light quantity ratio of the light source 2, the closer it is to the gamma curve C2. As will be described later, there are also examples of calculating the gamma curve statically and examples of calculating the gamma curve dynamically for each frame, pixel image, etc.

[0054] Then, using this gamma curve, the necessary gradation is obtained from the desired reflectance. In the figure, when assuming a certain reflectance, it shows that the gradation is different depending on the gamma curve, which means that the voltage value of the amplitude modulation drive signal is adjusted according to the adopted gamma curve according to the assumed reflectance. By performing this process for each of the RGB colors, the assumed reflectance for each color can be obtained, and as a result, the occurrence of color unevenness can be eliminated.

[0055] By the way, as the amplitude modulation element 5, it is possible to use a liquid crystal panel or a DMD. Furthermore, several types of characteristics of the light sources 1 and 2 can be assumed. Therefore, here, the configuration of the device in which the application of this technology is assumed and the types of color unevenness correction for it will be described.

[0056] First, the following two items can be considered as the characteristics of the light source. · Whether the wavelengths of R, G, and B of the light sources 1 and 2 are the same or different · Whether the white points (white balances) of the light sources 1 and 2 are the same or different

[0057] Next, the following two items can be considered from the perspective of the devices used as the phase modulation element 3 and the amplitude modulation element 5. · Whether to use a liquid crystal panel or a DMD as the phase modulation element 3 · Whether to use a liquid crystal panel or a DMD as the amplitude modulation element 5

[0058] As a result, a total of 16 types of configurations can be considered as shown in FIG. 12. These configurations can be roughly classified into cases where color unevenness correction indicated by "#4" in the figure is unnecessary and cases where color unevenness correction indicated by "#1", "#2", and "#3" is necessary. When color unevenness correction is necessary, it can be further divided into three types: correction of the white point of "#1", correction of the gamma curve of "#2", and correction of both the white point and the gamma curve of "#3". These will be described below.

[0059] · #1 When the wavelengths of the R, G, and B colors of the light sources 1 and 2 are the same and the white points of both light sources 1 and 2 are different, it is appropriate to perform white point correction according to the ratio of the first light source light 104 and the second light source light 106. Even when the wavelengths of the R, G, and B colors of the light sources 1 and 2 are different, the white points of both light sources 1 and 2 are different, and a DMD is used as the amplitude modulation element 5, it is similarly appropriate to perform white point correction.

[0060] · #2 When the wavelengths of the R, G, and B colors of the light sources 1 and 2 are different, the white points of both light sources 1 and 2 are the same, and a liquid crystal panel is used as the amplitude modulation element 5, it is appropriate to calculate the gamma curve according to the ratio of the first light source light 104 and the second light source light 106 and perform color unevenness correction.

[0061] · #3 When the wavelengths of the R, G, and B colors of the light sources 1 and 2 are different, the white points of both light sources 1 and 2 are different, and a liquid crystal panel is used as the amplitude modulation element 5, it is appropriate to correct color unevenness considering both the white point and the gamma curve.

[0062] ·#4 When the wavelengths of each of the R, G, and B colors of the light source 1 and the light source 2 are the same and the white points of both the light sources 1 and 2 are the same, since the gamma curve and the white point are the same, the gamma curve and the white point do not depend on the ratio of the first light source light 104 and the second light source light 106, and no color unevenness correction is required. Also, since the DMD has no wavelength dependence, even when the wavelengths of the light source 1 and the light source 2 are different but the white points of both the light sources 1 and 2 are made to coincide and the DMD is used as the amplitude modulation element 5, no color unevenness correction is necessary.

[0063] <4. Signal Processing of the First Embodiment> As a signal processing example of the first embodiment, an example of static color unevenness correction will be described with reference to FIG. 13. The process of FIG. 13 shows a case where the wavelengths and white balance of each primary color light of the light sources 1 and 2 are different and the amplitude modulation element 5 uses a liquid crystal panel.

[0064] Note that the processes of each embodiment described below with reference to FIGS. 13 to 16 are signal processing examples executed for each frame of the video signal D by the signal processing unit 10 of FIG. 4 having the drawing creation signal processing unit 11 and the phase pattern generation unit 12 as shown in FIG. 5. Also, in FIGS. 13, 14, and 16, when showing the signal processing content, it is shown as "S1", "S2",... and the information input and output related to the process is shown as "IM1", "IM2",... Also, in FIGS. 13, 14, and 16, in order to avoid complication of the figure, the three systems of R, G, and B are shown together without distinction, but it should be understood that each information (IM) and each process (S) are performed independently for each of R, G, and B.

[0065] In the example of FIG. 13, first, the signal processing unit 10 acquires the target luminance chromaticity distribution IM1. This is information representing the in-plane luminance and chromaticity distribution of the video to be projected, that is, it corresponds to the data of one frame of the video signal D.

[0066] The signal processing unit 10 extracts luminance information from the data of one frame as the video signal D in the luminance extraction process S1. Thereby, information as the luminance distribution IM2 is obtained. The luminance distribution is information on the light quantity distribution to be realized by phase modulation or amplitude modulation.

[0067] The signal processing unit 10 performs the first / second light quantity separation process S2 according to the luminance distribution (light quantity distribution) IM2. Thereby, as the light quantity IM5 by the light source 1, the light quantity with a uniform light quantity distribution within the plane is set. Also, as the light quantity distribution IM6 by the light source 2, a light quantity distribution IM6 in which the light quantity of a partial region is increased or the light quantity of a partial region is decreased according to the video content is set.

[0068] The signal processing unit 10 performs a phase calculation process S5 based on the light quantity distribution IM6 and obtains a phase distribution IM7. Based on this phase distribution IM7, the phase pattern signals PHr, PHg, PHb shown in FIG. 5 are generated and supplied to the phase modulation elements 3R, 3G, 3B.

[0069] On the other hand, the signal processing unit 10 performs a reflectance calculation process S3 regarding amplitude modulation. This is performed by dividing the target luminance chromaticity distribution IM1 by the luminance distribution (light quantity distribution) IM2. Thereby, reflectance distributions IM3 for R, G, and B are obtained.

[0070] Then, the signal processing unit 10 performs a calculation process S4 for the liquid crystal drive voltage for each of R, G, and B. This liquid crystal drive voltage is a voltage value applied to each pixel of the amplitude modulation elements 5R, 5G, 5B by the liquid crystal panel as the amplitude modulation drive signal Sd1.

[0071] The liquid crystal drive voltages for R, G, and B are calculated using the reflectance distributions IM3 for R, G, and B and the gamma curve. For example, if the gamma curve C1 in FIG. 11 is set, the gradation of each pixel is derived from the reflectance of each pixel defined by the reflectance distribution IM3, and thus the liquid crystal drive voltage for each pixel is calculated according to the gradation.

[0072] However, if the gamma curve C1 corresponding to the light source 1 or the gamma curve C2 corresponding to the light source 2 is used, as described above, color unevenness becomes a problem. Therefore, in the first embodiment, the gamma curve Cm obtained from the typical light quantity ratio between the first light source light 104 and the phase-modulated second light source light 106 is used. For example, calculations are performed on the gamma curves C1 and C2 using the light quantity ratio between the first light source light 104 and the second light source light 106 to calculate the gamma curve Cm. This is done for each of the R, G, and B colors. Therefore, for each of the amplitude modulation elements 5R, 5G, and 5B, the gamma curve Cm (hereinafter referred to as "CmR", "CmG", and "CmB" respectively) calculated based on the typical light quantity ratio is obtained. The signal processing unit 10 stores such gamma curves Cm corresponding to both light sources 1 and 2 as information IM4. Then, in the processing of each frame, the signal processing unit 10 performs the calculation process S4 of the liquid crystal drive voltage using the gamma curves CmR, CmG, and CmB as the information IM4 set in advance using these typical light quantity ratios.

[0073] Specifically, the signal processing unit 10 obtains the liquid crystal drive voltage for each pixel of the amplitude modulation element 5R using the reflectance distribution IM3 of the R light and the gamma curve CmR of the amplitude modulation element 5R for the R light. Similarly, the signal processing unit 10 obtains the liquid crystal drive voltage for each pixel of the amplitude modulation element 5G using the reflectance distribution IM3 of the G light and the gamma curve CmG of the amplitude modulation element 5G for the G light. Further, the signal processing unit 10 obtains the liquid crystal drive voltage for each pixel of the amplitude modulation element 5B using the reflectance distribution IM3 of the B light and the gamma curve CmB of the amplitude modulation element 5B for the B light.

[0074] Through such a calculation process S4, the liquid crystal drive voltage distributions IM8 for R, G, and B are obtained. Then, an amplitude modulation drive signal Sd1 corresponding to this voltage distribution is supplied to the amplitude modulation elements 5R, 5G, and 5B.

[0075] In the processing example of the above first embodiment, the gamma curves CmR, CmG, and CmB of the amplitude modulation elements 5R, 5G, and 5B are the gamma curves when the first light source light 104 and the second light source light 106 are added together at a certain representative ratio. Since these gamma curves CmR, CmG, and CmB are static, color unevenness can be eliminated when the first light source light 104 and the second light source light 106 are incident at the ratio determined as the representative ratio, but color unevenness occurs at other ratios. However, compared with the case of using the gamma curve C1 corresponding to the light source 1 and the gamma curve C2 corresponding to the light source 2, color unevenness can be reduced.

[0076] Note that this first embodiment is effective when using two light sources with different wavelengths for each of R, G, and B, and is also effective when not using the phase modulation element 3. For example, it is a configuration in which light from two light sources is incident on the amplitude modulation element 5. In that case, a distribution like a boost in the light amount in a partial region in the plane does not occur for both light sources 1 and 2, and the light amount ratio from each light source in the plane becomes equal in each frame (time). Therefore, if the amplitude modulation drive signal Sd1 is calculated using the gamma curve corresponding to the light amount ratio of the two light sources incident on the amplitude modulation element 5, color unevenness can be prevented from occurring.

[0077] However, even in the case of a configuration without using the phase modulation element 3 like this, if the light amount ratio from each light source differs depending on the frame, a color difference will occur between frames. Even in such a case, if the amplitude modulation drive signal Sd1 is calculated using the gamma curve corresponding to the representative light amount ratio of the two light sources, color unevenness can be reduced.

[0078] <5. Signal Processing of the Second Embodiment> An example of the signal processing of the second embodiment is shown in FIG. 14. This is an example of dynamically correcting color unevenness when the wavelengths of the primary color lights of the light sources 1 and 2 are different and the amplitude modulation element 5 uses a liquid crystal panel.

[0079] Even in the example of FIG. 14, the signal processing unit 10 acquires the target luminance chrominance distribution IM1 as data for each frame of the video signal D. Then, as the luminance extraction process S1, the signal processing unit 10 extracts luminance information from the data of one frame as the video signal D. Thereby, information as the luminance distribution (light quantity distribution) IM2 is obtained.

[0080] The signal processing unit 10 performs the first / second light quantity separation process S2 according to the luminance distribution (light quantity distribution) IM2. Thereby, as the light quantity IM5 by the light source 1, the light quantity of a uniform light quantity distribution within the plane is set. Also, as the light quantity distribution IM6 by the light source 2, a light quantity distribution IM6 in which the light quantity of a partial region is increased or the light quantity of a partial region is decreased according to the video content is set.

[0081] The signal processing unit 10 performs the phase calculation process S5 based on the light quantity distribution IM6 to obtain the phase distribution IM7. Based on this phase distribution IM7, the phase pattern signals PHr, PHg, and PHb shown in FIG. 5 are generated and supplied to the phase modulation elements 3R, 3G, and 3B.

[0082] On the other hand, the signal processing unit 10 performs the light quantity ratio calculation process S10 of the first light source light 104 and the second light source light 106 regarding amplitude modulation. That is, it is a process of calculating the ratio of the first light source light 104 and the second light source light 106 in each region within the plane from the light quantity IM5 of the light source 1 and the light quantity distribution IM6 of the light source 2. Thereby, the light quantity ratio distribution IM12 of the first light source light 104 and the second light source light 106 in the current frame is obtained.

[0083] The signal processing unit 10 performs the calculation process S11 of calculating the gamma curve Cm in the current frame using the information IM10 of the gamma curve C1 for the light source 1, the information IM11 of the gamma curve C2 for the light source 2, and the light quantity ratio distribution IM12. Then, a gamma curve distribution IM13 within the plane according to the calculation result is obtained, and the calculation process S12 of the liquid crystal drive voltage is performed using the gamma curve distribution IM13.

[0084] As the calculation process S11 of the gamma curve Cm, the following examples (processing example a), (processing example b), and (processing example c) can be considered. (Processing example a) Obtain the gamma curve Cm to be applied to all in-plane pixels in the current frame. (Processing example b) Obtain the gamma curve Cm to be applied to each block in the plane in the current frame. (Processing example c) Obtain the gamma curve Cm to be applied to each pixel in the plane in the current frame.

[0085] First, the example of the above (processing example a) will be described. FIG. 15A shows the entire area in the plane that forms one frame of video. Calculate the gamma curve Cm to be applied to all the pixels in this plane. In this case, obtain a representative light amount ratio from the light amount ratio distribution IM12 of the current frame. Then, using the representative light amount ratio, calculate the gamma curve Cm that reflects the respective ratios of the gamma curve C1 for light source 1 and the gamma curve C2 for light source 2.

[0086] Specifically, in such a method, the signal processing unit 10 calculates the gamma curves CmR, CmG, and CmB calculated with the representative light amount ratio in the current frame for each of the amplitude modulation elements 5R, 5G, and 5B. That is, the signal processing unit 10 uses the light amount ratio distribution IM12 of R light in the current frame and the gamma curves C1 and C2 corresponding to light sources 1 and 2 for the amplitude modulation element 5R to obtain the gamma curve CmR to be applied to the amplitude modulation element 5R for the current frame. Similarly, the signal processing unit 10 uses the light amount ratio distribution IM12 of G light in the current frame and the gamma curves C1 and C2 corresponding to light sources 1 and 2 for the amplitude modulation element 5G to obtain the gamma curve CmG to be applied to the amplitude modulation element 5G for the current frame. Furthermore, the signal processing unit 10 uses the light amount ratio distribution IM12 of B light in the current frame and the gamma curves C1 and C2 corresponding to light sources 1 and 2 for the amplitude modulation element 5B to obtain the gamma curve CmB to be applied to the amplitude modulation element 5B for the current frame.

[0087] Thus, the gamma curves CmR, CmG, and CmB to be applied to the current frame are obtained. However, in the case of this (processing example a), the gamma curve distribution IM13 is uniform within the plane. Then, as the calculation process S12 of the liquid crystal drive voltage, the signal processing unit 10 uses the reflectance distributions IM3 of R, G, and B obtained by dividing the target luminance chromaticity distribution IM1 by the luminance distribution (light quantity distribution) IM2, and the gamma curves CmR, CmG, and CmB to obtain the liquid crystal drive voltages of the respective pixels of the amplitude modulation elements 5R, 5G, and 5B. As a result, the liquid crystal drive voltage distributions IM8 of R, G, and B are obtained, and an amplitude modulation drive signal Sd1 corresponding to this voltage distribution is supplied to the amplitude modulation elements 5R, 5G, and 5B.

[0088] According to this (processing example a), for each frame, the gamma curve Cm is dynamically obtained based on the ratio of the first light source light 104 and the second light source light 106 in that frame, and the amplitude modulation drive signal Sd1 is obtained, so that the color unevenness reduction effect can be made higher than that of the first embodiment.

[0089] Subsequently, the example of the above (processing example b) will be described. FIG. 15B shows an example in which the plane forming the video of one frame is divided into several blocks BK. One block is a region composed of a plurality of pixels. Here, an example in which the plane of one frame is divided into eight blocks BK is shown, but the number of blocks BK for dividing the plane, the number of pixels constituting the block BK, and the shape of the block BK can be considered in various ways.

[0090] Based on the setting of such a block BK, the signal processing unit 10 obtains a representative light quantity ratio for each block BK from the light quantity ratio distribution IM12 of the current frame. Then, for each block BK, a gamma curve Cm reflecting the respective ratios of the gamma curve C1 for the light source 1 and the gamma curve C2 for the light source 2 is calculated using the representative light quantity ratio.

[0091] Specifically, the signal processing unit 10 uses the calculation process S11 to obtain the gamma curve CmR to be applied to each block BK of the R light in the current frame based on the light amount ratio distribution IM12 of each block BK of the R light and the gamma curves C1 and C2 corresponding to the light sources 1 and 2 of the amplitude modulation element 5R in the current frame. For example, the gamma curves CmR to be applied to each block BK, such as the gamma curve CmR(BK1) for the first block BK, the gamma curve CmR(BK2) for the second block BK, ··· CmR(BKm), are obtained. Here, "m" is the number of blocks.

[0092] Similarly, for the amplitude modulation element 5G, the gamma curves CmG to be applied to each block BK are obtained, that is, in this case, the gamma curves CmG(BK1), CmG(BK2), ··· CmG(BKm). Similarly, for the amplitude modulation element 5B, the gamma curves CmB to be applied to each block BK are obtained, that is, in this case, the gamma curves CmB(BK1), CmB(BK2), ··· CmB(BKm).

[0093] By obtaining the gamma curves CmR, CmG, and CmB to be applied to each block BK in the current frame in this way, a gamma curve distribution IM13 with different gamma curves for each block BK is obtained. Then, the signal processing unit 10 uses the calculation process S12 with the reflectance distributions IM3 of R, G, and B respectively and the gamma curves CmR, CmG, and CmB for each block BK to obtain the liquid crystal drive voltages of each pixel of the amplitude modulation elements 5R, 5G, and 5B. As a result, the liquid crystal drive voltage distributions IM8 of R, G, and B are obtained, and an amplitude modulation drive signal Sd1 corresponding to this voltage distribution is supplied to the amplitude modulation elements 5R, 5G, and 5B.

[0094] According to this (processing example b), for each frame and for each block BK in that frame, the gamma curve Cm is dynamically obtained based on the ratio of the first light source light 104 and the second light source light 106, and the amplitude modulation drive signal Sd1 is obtained, so that the effect of reducing color unevenness can be further enhanced.

[0095] Next, an example of the above (processing example c) will be described. FIG. 15C shows each pixel PX in the plane that forms one frame of video. One cell of the grid represents one pixel. Note that the figure is schematic and the number of pixels does not conform to the actual situation. Then, in the calculation process S11, the signal processing unit 10 calculates a gamma curve Cm that reflects the respective ratios of the gamma curve C1 for the light source 1 and the gamma curve C2 for the light source 2, using the light quantity ratios indicated for each pixel PX in the light quantity ratio distribution IM12 of the current frame.

[0096] Specifically, using the light quantity ratio for each pixel PX of the R light in the current frame and the gamma curves C1 and C2 corresponding to the light sources 1 and 2 for the amplitude modulation element 5R, a gamma curve CmR to be applied to each pixel PX of the amplitude modulation element 5R for the current frame is obtained. For example, gamma curves CmR(PX1), CmR(PX2) ··· CmR(PXn) are obtained, that is, gamma curves CmR to be applied to each pixel PX are obtained. Note that "n" is the number of pixels.

[0097] Similarly, for the amplitude modulation element 5G, gamma curves CmG to be applied to each pixel PX are obtained, that is, in this case, gamma curves CmG(PX1), CmG(PX2) ··· CmG(PXn). Similarly, for the amplitude modulation element 5B, gamma curves CmB to be applied to each pixel PX are obtained, that is, in this case, gamma curves CmB(PX1), CmB(PX2) ··· CmB(PXn).

[0098] By obtaining the gamma curves CmR, CmG, and CmB to be applied to each pixel PX in the current frame in this way, a gamma curve distribution IM13 with different gamma curves for each pixel PX is obtained. Then, the signal processing unit 10 uses the reflectance distributions IM3 of R, G, and B respectively and the gamma curves CmR, CmG, and CmB for each pixel PX to perform a calculation process S12 to obtain the liquid crystal drive voltages for the respective pixels of the amplitude modulation elements 5R, 5G, and 5B. As a result, the liquid crystal drive voltage distributions IM8 of R, G, and B are obtained, and an amplitude modulation drive signal Sd1 corresponding to this voltage distribution is supplied to the amplitude modulation elements 5R, 5G, and 5B.

[0099] According to this (processing example c), for each frame and for each pixel PX, a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 is obtained, and by obtaining the amplitude modulation drive signal Sd1, color unevenness can be eliminated.

[0100] In the above (processing example b) and (processing example c), an example of obtaining the gamma curve Cm for each block BK or for each pixel PX has been described. However, an example of obtaining the gamma curve Cm for each such in-plane region can also be applied to the first embodiment. That is, in the first embodiment, a representative ratio of the first light source light 104 and the second light source light 106 is obtained for each block BK or for each pixel PX. Then, fixed gamma curves CmR, CmG, and CmB for static correction may be prepared for each block BK or for each pixel PX and used in the calculation of the amplitude modulation drive signal Sd1.

[0101] <6. Signal Processing of the Third Embodiment> The third embodiment will be described with reference to FIG. 16. Since the processing example of this FIG. 16 has many similarities with FIG. 14, the same reference numerals are given to the same processes and information, and only the differences will be described.

[0102] In FIG. 16, the signal processing unit 10 performs a calculation process S20 for calculating the gamma curve Cm in the current frame using the gamma curve C1 and white balance information IM20 for the light source 1, the gamma curve C2 and white balance information IM21 for the light source 2, and the light quantity ratio distribution IM12. Therefore, the obtained gamma curves CmR, CmG, and CmB assume differences in light quantity ratio and white balance.

[0103] Then, the signal processing unit 10 obtains an in-plane gamma curve distribution IM13 according to the calculation result of the calculation process S20, and performs a calculation process S12 of the liquid crystal drive voltage using the gamma curve distribution IM13. The rest is the same as in FIG. 14. Also in this case, processes corresponding to the respective examples of (process example a), (process example b), and (process example c) described in FIG. 14 can be considered.

[0104] In the case of this third embodiment, when the white balances of the light source 1 and the light source 2 are different, color unevenness correction that reduces the influence of the difference can be realized.

[0105] <7. Summary and Modification Examples> According to the above embodiments, the following effects can be obtained. The projector device of the embodiment includes a light source 1 (first light source) that outputs first light source light 104, and a light source 2 (second light source) that outputs second light source light 106 whose primary color light wavelength is different from the primary color light wavelength of the light source 1. The projector device also includes an amplitude modulation element 5 that receives both the first light source light 104 and the second light source light 106 and performs amplitude modulation on the incident light, and a signal processing unit 10 that generates an amplitude modulation drive signal Sd1 for the amplitude modulation element 5 based on a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5. Each of the R light, G light, and B light of the first light source light 104 and the second light source light 106 is incident on the amplitude modulation element 5, but the wavelengths of the respective primary color lights are different from each other. For this reason, as described in FIGS. 7 and 8, neither the gamma curve C1 of the amplitude modulation element 5 assuming the light source 1 nor the gamma curve C2 of the amplitude modulation element 5 assuming the light source 2 becomes a gamma curve for obtaining appropriate gradation projection video light, and color unevenness occurs. Therefore, a gamma curve corresponding to the ratio of the first light source light 104 and the second light source light 106 is calculated, and an amplitude modulation drive signal is generated based on it. Thereby, an amplitude modulation drive signal based on a more appropriate gamma curve can be generated, and color unevenness can be reduced or eliminated.

[0106] In the configuration of FIG. 5, a configuration that does not include the projection lens 9 can be considered as the light source device. Therefore, the present technology can also be applied to a light source device that is not configured as a projector device.

[0107] In the configuration example of the embodiment, a phase modulation element 3 for converting the light quantity distribution of the light from the light source 2 is provided, and both the first light source light 104 and the second light source light 106 that has passed through the phase modulation element 3 are incident on the amplitude modulation element 5. The first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5 not only have different wavelengths of R light, G light, and B light from each other, but also the light quantity distribution of the second light source light 106 is made non-uniform by the phase modulation element 3. For this reason, the light quantity ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element varies in a frame or in-plane region. In that case, when the amplitude modulation drive signal Sd1 is generated using the gamma curve C1 assuming the light source 1 and the gamma curve C2 assuming the light source 2, the problem of color unevenness becomes significant. Therefore, in such a configuration, it is effective to calculate a gamma curve corresponding to the ratio of the first light source light 104 and the second light source light 106 that has passed through the phase modulation element 3, and generate the amplitude modulation drive signal Sd1 based on it. Thereby, an amplitude modulation drive signal based on a more appropriate gamma curve can be generated, and color unevenness can be reduced or eliminated.

[0108] The amplitude modulation drive signal Sd1 described in the embodiment is a signal for controlling the light quantity of each pixel of the amplitude modulation element 5 according to the video signal D, and the control value of each pixel of the amplitude modulation element 5 corresponding to the gradation value of each pixel in the video signal D is generated based on the gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106. By controlling the reflectance or transmittance of the amplitude modulation element 5 by the amplitude modulation drive signal Sd1 corresponding to the video signal D to control the light quantity, the projection video irradiates video light corresponding to the video signal. In this case, by setting the control value of each pixel, for example, the drive voltage value of the liquid crystal panel, based on the gamma curve Cm corresponding to the ratio of the first light source light 104 and the phase-modulated second light source light 106, amplitude modulation suitable for the synthesized light is performed, and color unevenness can be reduced or eliminated.

[0109] In the second embodiment, an example was described in which the signal processing unit 10 obtains a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5 for each frame of the video signal D, and generates an amplitude modulation drive signal Sd1. When the ratio of the first light source light 104 and the phase-modulated second light source light 106 incident on the amplitude modulation element 5 changes for each frame of the video signal, by calculating a gamma curve Cm suitable for each frame and using the gamma curve Cm to generate the amplitude modulation drive signal Sd1, the effect of reducing color unevenness can be improved.

[0110] In the second embodiment, an example was described in which the signal processing unit 10 obtains a gamma curve Cm corresponding to the ratio of the incident first light source light 104 and the second light source light 106 for each pixel block BK obtained by dividing the plane of the amplitude modulation element 5, and generates an amplitude modulation drive signal Sd1 (processing example b). In one screen of the projected video, the light quantity distribution by the phase modulation element 3 changes. Therefore, the light quantity ratio of the first light source light 104 and the second light source light 106 is different within the plane of the amplitude modulation element 5. Therefore, as in (processing example b), for each pixel block BK obtained by dividing the plane of the amplitude modulation element 5, a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5 is calculated, and the amplitude modulation drive signal Sd1 is generated using the gamma curve Cm. Thereby, amplitude modulation drive is performed corresponding to the light quantity ratio for each region of each block BK within the plane, and the effect of reducing color unevenness can be improved. In particular, by calculating the gamma curve Cm for each block BK for each frame, it becomes possible to cope with both the difference in the light quantity ratio within the plane and the difference in the light quantity ratio on the time axis, and the effect of reducing color unevenness becomes more remarkable. Note that using the gamma curve Cm for each block BK as in (Processing Example b) is also effective when performing the static color unevenness correction in the first embodiment.

[0111] In the second embodiment, an example was described (Processing Example c) in which the signal processing unit 10 obtains a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 incident on each pixel PX of the amplitude modulation element 5 and generates the amplitude modulation drive signal Sd1. In one screen of the projected image, since the light amount distribution by the phase modulation element 3 changes for each pixel PX, the light amount ratio of the first light source light 104 and the second light source light 106 within the plane of the amplitude modulation element 5 differs for each pixel PX. Therefore, as in (Processing Example c), for each pixel PX of the amplitude modulation element 5, a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5 is calculated, and the amplitude modulation drive signal Sd1 is generated using the gamma curve Cm. Thereby, amplitude modulation driving is performed corresponding to the light amount ratio for each pixel within the plane, and color unevenness can be effectively reduced. In particular, by calculating the gamma curve Cm for each pixel PX for each frame, it becomes possible to cope with both the difference in the light amount ratio for each pixel within the plane and the difference in the light amount ratio on the time axis, and the occurrence of color unevenness can be almost eliminated. Note that using the gamma curve Cm for each pixel PX as in (Processing Example c) is also effective when performing the static color unevenness correction in the first embodiment.

[0112] In the first embodiment, the signal processing unit 10 obtains a gamma curve Cm corresponding to the representative value of the ratio of the first light source light 104 and the second light source light 106 incident on the amplitude modulation element 5 and generates the amplitude modulation drive signal Sd1. By generating the amplitude modulation drive signal Sd1 using the gamma curve Cm corresponding to a representative ratio as the ratio of the first light source light 104 and the second light source light 106, the effect of reducing color unevenness can be obtained. This is a static color unevenness reduction method when the wavelengths of the primary color lights and the white balance for the light source 1 and the light source 2 are different, and color unevenness reduction can be realized in a state with a relatively small processing load.

[0113] In the third embodiment, an example was given in which the signal processing unit 10 generates an amplitude modulation drive signal Sd1 for correcting the difference in white balance between the light source 1 and the light source 2. As described with reference to FIG. 16, by including the difference in white balance between the light source 1 and the light source 2 in the calculation of the gamma curve Cm, it becomes possible to obtain an effect of reducing color unevenness caused by the difference in white balance.

[0114] In the embodiment, the phase modulation element 3 is configured to convert incident light into outgoing light with different light beam densities for each in-plane region according to the phase pattern signals PHr, PHg, and PHb generated based on the video signal D. By interposing such a phase modulation element 3, it becomes possible to obtain projection video light 107 having a light quantity distribution including partial increases and decreases in light quantity according to the video signal D, and realize video projection with a wide dynamic range.

[0115] In the embodiment, the amplitude modulation element 5 is assumed to be composed of a liquid crystal panel or a DMD. By calculating a gamma curve Cm corresponding to the ratio of the first light source light 104 and the second light source light 106 according to the characteristics of the liquid crystal panel or DMD, and generating an amplitude modulation drive signal Sd1 based on it, it is possible to reduce color unevenness corresponding to the device type of the amplitude modulation element 5.

[0116] In the embodiment, as an example of primary color light, the wavelengths of the red light from the light source 1 and the red light from the light source 2, the green light from the light source 1 and the green light from the light source 2, and the blue light from the light source 1 and the blue light from the light source 2 are different from each other. Regarding the light sources 1 and 2, the fact that the wavelengths of R light, G light, and B light are different from each other is a factor causing color unevenness. In this case, generating an amplitude modulation drive signal Sd1 based on a gamma curve according to the light quantity ratio is particularly effective for improving the image quality by reducing color unevenness. Note that, for example, a case is also assumed where some of the wavelengths of R light, G light, and B light from the first light source and the R light, G light, and B light from the second light source are different from each other between the first light source and the second light source, and the technology of the embodiment can also be applied in that case.

[0117] In the embodiment, one of the light source 1 and the light source 2 is a laser light source, and the other is constituted by another light source device. By using a laser light source for one of the light source 1 and the light source 2 and another light source device such as a phosphor light source for the other, it is possible to relatively inexpensively achieve higher brightness of the projected image. In this case, color unevenness occurs due to the difference in the wavelengths of the primary color lights, but the color unevenness can be reduced or eliminated by the technique described in the embodiment. As a result, a projector device that realizes a high-brightness and high-quality projected image can be realized at a relatively low cost.

[0118] Although the embodiment has taken the configuration of performing color video projection using R, G, and B as an example, the present technology is also effective when using primary color lights of other combinations. It can also be applied to a projector device or a light source device that performs monochrome video projection.

[0119] Note that the effects described in this specification are merely examples and are not limited, and there may be other effects.

[0120] Note that the present technology can also adopt the following configurations. (1) A first light source that outputs first light source light, A second light source that outputs second light source light whose primary color light wavelength is different from the primary color light wavelength of the first light source, An amplitude modulation element into which both the first light source light and the second light source light are incident and that performs amplitude modulation on the incident light, A signal processing unit that generates an amplitude modulation drive signal for the amplitude modulation element based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element, A projector device. (2) A phase modulation element that converts the light quantity distribution of the second light source light is provided, Both the first light source light and the second light source light that has passed through the phase modulation element are incident on the amplitude modulation element The projector device according to (1) above. (3) The amplitude modulation drive signal is a signal for controlling the light amount of each pixel of the amplitude modulation element according to a video signal. The control value of each pixel of the amplitude modulation element according to the gradation value of each pixel in the video signal is generated based on a gamma curve according to the ratio of the first light source light and the second light source light. The projector device according to (1) or (2) above. (4) The signal processing unit For each frame of the video signal, obtains a gamma curve according to the ratio of the first light source light and the second light source light incident on the amplitude modulation element, and generates the amplitude modulation drive signal. The projector device according to any one of (1) to (3) above. (5) The signal processing unit For each pixel block obtained by dividing the plane of the amplitude modulation element, obtains a gamma curve according to the ratio of the first light source light and the second light source light incident thereon, and generates the amplitude modulation drive signal. The projector device according to any one of (1) to (4) above. (6) The signal processing unit For each pixel of the amplitude modulation element, obtains a gamma curve according to the ratio of the first light source light and the second light source light incident thereon, and generates the amplitude modulation drive signal. The projector device according to any one of (1) to (4) above. (7) The signal processing unit Obtains a gamma curve according to a representative value of the ratio of the first light source light and the second light source light incident on the amplitude modulation element, and generates the amplitude modulation drive signal. The projector device according to any one of (1) to (3) above. (8) The signal processing unit Generates the amplitude modulation drive signal for correcting the difference in white balance between the first light source and the second light source. The projector device according to any one of (1) to (7) above. (9) The phase modulation element is configured to convert incident light into outgoing light with different light beam densities for each in-plane region according to a phase pattern generated based on a video signal The projector device according to (2) above. (10) The amplitude modulation element is constituted by a liquid crystal panel The projector device according to any one of (1) to (9) above. (11) The amplitude modulation element is constituted by a digital micromirror device The projector device according to any one of (1) to (9) above. (12) As the primary color light, red light from the first light source and red light from the second light source, green light from the first light source and green light from the second light source, blue light from the first light source and blue light from the second light source, each having different wavelengths The projector device according to any one of (1) to (11) above. (13) One of the first light source and the second light source is a laser light source, and the other is constituted by another light source device The projector device according to any one of (1) to (11) above. (14) A first light source that outputs first light source light, A second light source that outputs second light source light whose primary color light wavelength is different from that of the primary color light of the first light source, An amplitude modulation element into which both the first light source light and the second light source light are incident and which performs amplitude modulation on the incident light, A signal processing unit that generates an amplitude modulation drive signal for the amplitude modulation element based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element. A light source device. (15) A first light source that outputs first light source light, A second light source that outputs second light source light whose wavelength of primary color light is different from the wavelength of the primary color light of the first light source, an amplitude modulation element that receives both the first light source light and the second light source light and performs amplitude modulation on the incident light, In a light source device including: driving the amplitude modulation element with an amplitude modulation drive signal generated based on a gamma curve corresponding to a ratio of the first light source light and the second light source light incident on the amplitude modulation element Light source driving method.

Explanation of symbols

[0121] 1 Light source (first light source) 2 Light source (second light source) 3, 3R, 3G, 3B Phase modulation element 4 Combining optical system 5, 5R, 5G, 5B Amplitude modulation element 6 Second illumination optical system 7 Relay optical system 8 First illumination optical system 9 Projection lens 10 Signal processing unit 11 Image creation signal processing unit 12 Phase pattern generation unit 104 First light source light 105, 106 Second light source light 107 Projected image light 110 Reflectance distribution

Claims

1. a first light source that outputs first light source light; a second light source that outputs second light source light whose primary color light wavelength is different from the primary color light wavelength of the first light source; an amplitude modulation element into which both the first light source light and the second light source light are incident and that performs amplitude modulation on the incident light; a signal processing unit that generates an amplitude modulation drive signal for the amplitude modulation element based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element; and a projector device.

2. comprising a phase modulation element that converts the light quantity distribution of the second light source light, wherein both the first light source light and the second light source light that has passed through the phase modulation element are incident on the amplitude modulation element The projector device according to claim 1.

3. The amplitude modulation drive signal is a signal that controls the light quantity of each pixel of the amplitude modulation element according to a video signal, and the control value of each pixel of the amplitude modulation element according to the gradation value of each pixel in the video signal is generated based on a gamma curve corresponding to the ratio of the first light source light and the second light source light. The projector device according to claim 1.

4. The signal processing unit obtains a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element for each frame of the video signal, and generates the amplitude modulation drive signal. The projector device according to claim 1.

5. The signal processing unit obtains a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element for each pixel block obtained by dividing the plane of the amplitude modulation element, and generates the amplitude modulation drive signal. The projector device according to claim 1.

6. The signal processing unit obtains a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element for each pixel of the amplitude modulation element, and generates the amplitude modulation drive signal. The projector device according to claim 1.

7. The signal processing unit obtains a gamma curve corresponding to the representative value of the ratio of the first light source light and the second light source light incident on the amplitude modulation element, and generates the amplitude modulation drive signal. The projector device according to claim 1.

8. The signal processing unit generates the amplitude modulation drive signal that corrects the difference in white balance between the first light source and the second light source. The projector device according to claim 1.

9. The phase modulation element Convert the incident light into outgoing light with different light beam densities for each in-plane region according to the phase pattern generated based on the video signal. The projector device according to claim 2.

10. The amplitude modulation element is constituted by a liquid crystal panel. The projector device according to claim 1.

11. The amplitude modulation element is constituted by a digital micromirror device. The projector device according to claim 1.

12. As the primary color light, Red light from the first light source and red light from the second light source, Green light from the first light source and green light from the second light source, Blue light from the first light source and blue light from the second light source, each having different wavelengths The projector device according to claim 1.

13. One of the first light source and the second light source is a laser light source, and the other is constituted by another light source device. The projector device according to claim 1.

14. A first light source that outputs first light source light, A second light source that outputs second light source light whose primary color light wavelength is different from that of the primary color light of the first light source, An amplitude modulation element into which the first light source light and the second light source light are both incident and that performs amplitude modulation on the incident light, A signal processing unit that generates an amplitude modulation drive signal for the amplitude modulation element based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element. Light source device.

15. A first light source that outputs first light source light, A second light source that outputs second light source light whose primary color light wavelength is different from that of the primary color light of the first light source, An amplitude modulation element into which the first light source light and the second light source light are both incident and that performs amplitude modulation on the incident light, In a light source device comprising: Drive the amplitude modulation element with an amplitude modulation drive signal generated based on a gamma curve corresponding to the ratio of the first light source light and the second light source light incident on the amplitude modulation element. Light source driving method.

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