JP2012181531A - Image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device for achieving high contrast by displaying dark images in low brightness and displaying a bright point in high brightness with low power consumption.SOLUTION: An image display device 200 comprises: a light source 210; a diffraction optical element 220 for diffracting light radiated from the light source 210; and a light modulation element 230 for modulating diffraction light diffracted with the diffraction optical element 220. In the image display device 200, diffraction characteristics of the diffraction optical element 220 is controlled based on a given diffraction optical element control signal.

Description

  The present invention relates to an image display device.

  Conventionally, a projection type image display apparatus (projector) using a light source such as a laser is known. In this type of projection-type image display apparatus, for example, the laser beams of RGB color components are subjected to luminance modulation in accordance with an image signal and then combined to display an image. In recent years, projection-type image display devices are not limited to the above-described methods, and higher resolution and higher contrast are required, and higher image quality is being promoted.

  One of the problems to be solved by such a projection type image display apparatus that performs an image display apparatus with a light source is a decrease in contrast caused by light leakage or stray light generated by an optical element constituting the optical system. Various techniques for suppressing the decrease in contrast have been proposed. For example, Patent Document 1 includes a movable shielding plate, and displays a dark image by adjusting the amount of light applied to the light modulation element from the light source. A technique for artificially improving the contrast by reducing the amount of light is disclosed.

JP 2005-17500 A

  However, in the technique disclosed in Patent Document 1, in order to uniformly adjust the light amount of the entire screen, when a bright spot (light source or glossy image) exists in a dark image, the brightness of the bright spot is reduced. There is a problem of generating a so-called black float.

  The present invention has been made in view of the above technical problems, and the object of the present invention is to realize high contrast by displaying bright spots with high brightness and displaying dark images with low brightness. An image display device is provided.

  In order to solve the above problems, the present invention includes a light source, a diffractive optical element that diffracts the light emitted from the light source, and a light modulation element that modulates the diffracted light diffracted by the diffractive optical element. The present invention relates to an image display apparatus in which the diffraction characteristics of the diffractive optical element are controlled based on a given diffractive optical element control signal.

  According to the present invention, a diffractive optical element is provided between a light source and a light modulation element, and an image can be displayed by optically modulating diffracted light obtained by diffracting light from the light source into a desired luminance distribution. Therefore, by using the amount of light from the light source for other parts in the image, it is possible to realize high contrast by displaying bright spots with high luminance and displaying dark images with low luminance.

  In addition, according to the present invention, since the amount of light of the entire screen is not adjusted uniformly, for example, even when a bright spot (light source or glossy part) exists in the image, a decrease in brightness of the bright spot is suppressed, The occurrence of so-called black float can be suppressed.

  Further, the present invention is provided with a plurality of light sources provided for each color component, a diffractive optical element that is shared by the plurality of light sources and diffracts light emitted from the plurality of light sources, and is provided for each of the color components, A plurality of light modulation elements that modulate the diffracted light diffracted by the diffractive optical element, and relates to an image display device in which diffraction characteristics of the diffractive optical element are controlled based on a given diffractive optical element control signal .

  According to the present invention, a diffractive optical element is provided between a light source and a light modulation element, and an image can be displayed by optically modulating diffracted light obtained by diffracting light from the light source into a desired luminance distribution. Therefore, by using the amount of light from the light source for other parts in the image, it is possible to realize high contrast by displaying bright spots with high luminance and displaying dark images with low luminance.

  In addition, according to the present invention, since the amount of light of the entire screen is not adjusted uniformly, for example, even when a bright spot (light source or glossy part) exists in the image, a decrease in brightness of the bright spot is suppressed, The occurrence of so-called black float can be suppressed.

  Furthermore, according to the present invention, since the diffractive optical element is shared for a plurality of light sources, the number of parts of the image display device is greatly reduced, contributing to cost reduction and power consumption of the image display device. become able to.

  In the image display device according to the present invention, the intensity of light from each of the plurality of light sources may be controlled to be the same, and the modulation amount of each of the plurality of light modulation elements may be controlled for each color component. .

  According to the present invention, in addition to the above-described effects, control is performed so that the intensities of the light sources are uniform, so that control of image display using the diffractive optical element and the light modulation element can be simplified.

  The present invention also provides a plurality of light sources provided for each color component, and a plurality of diffractive optical elements provided for each color component, wherein each diffractive optical element diffracts light emitted from each light source of the plurality of light sources. A plurality of light modulation elements provided for each of the color components, each light modulation element modulating the diffracted light diffracted by each diffractive optical element of the plurality of diffractive optical elements, and a given diffractive optical element The present invention relates to an image display device in which diffraction characteristics of each diffractive optical element are controlled based on a control signal.

  According to the present invention, a diffractive optical element is provided between a light source and a light modulation element, and an image can be displayed by optically modulating diffracted light obtained by diffracting light from the light source into a desired luminance distribution. Therefore, by using the amount of light from the light source for other parts in the image, it is possible to realize high contrast by displaying bright spots with high luminance and displaying dark images with low luminance.

  In addition, according to the present invention, since the amount of light of the entire screen is not adjusted uniformly, for example, even when a bright spot (light source or glossy part) exists in the image, a decrease in brightness of the bright spot is suppressed, The occurrence of so-called black float can be suppressed.

  Furthermore, according to the present invention, since the diffractive optical element is provided for each light source, the intensity of the light source can be controlled for each color component, and the intensity of the light source for each color component does not need to be uniformed. Compared with the case where the control is performed in a uniform manner, the intensity of the light source is not increased unnecessarily, and low power consumption can be realized.

  In the image display device according to the present invention, the light intensity of each of the plurality of light sources may be controlled for each color component, and the modulation amount of each of the plurality of light modulation elements may be controlled for each color component.

  According to the present invention, since the diffractive optical element, the light modulation element, and the light source can be finely controlled, it is possible to contribute to further prevention of image quality deterioration and low power consumption.

  In the image display device according to the present invention, the diffractive optical element control signal may be a signal generated based on an input image signal.

  According to the present invention, when displaying an image according to an input image signal, it is possible to provide an image display device that realizes high contrast by displaying bright spots with high brightness and displaying dark images with low brightness. become.

  In the image display device according to the present invention, the diffractive optical element control signal may be generated using a diffraction pattern corresponding to an illumination distribution of light from the light source calculated based on the input image signal.

  According to the present invention, a process for using light from a light source that is originally focused to express a dark part of an image as light of another part in the image using the diffraction pattern of the diffractive optical element is simplified. It becomes possible to become.

  In the image display device according to the present invention, the light source may generate coherent light.

  According to the present invention, since the diffraction phenomenon of the diffractive optical element is used, the image quality of the display image can be improved by using coherent light.

1 is a block diagram of a configuration example of an image display system according to a first embodiment of the present invention. 1 is a block diagram of a configuration example of an image display device according to a first embodiment of the present invention. 1 is a schematic plan view of a diffractive optical element according to a first embodiment. FIG. 4 is a schematic cross-sectional view taken along the line AA of the diffractive optical element of FIG. Explanatory drawing of the function of the diffractive optical element in 1st Embodiment. 1 is a block diagram of a configuration example of an image processing apparatus according to a first embodiment. FIG. 7 is a block diagram of a configuration example of a main part of the image processing apparatus in FIG. 6. FIG. 3 is a flowchart of a processing example of the image processing apparatus according to the first embodiment. 1 is a block diagram of a hardware configuration example of an image processing apparatus according to a first embodiment. The block diagram of the example of composition of the principal part of the image processor in the modification of a 1st embodiment. The flowchart of the example of a process of the image processing apparatus in the modification of 1st Embodiment. The block diagram of the structural example of the image display system in the 2nd Embodiment of this invention. The block diagram of the structural example of the image processing apparatus in 2nd Embodiment. FIG. 9 is a flowchart of a processing example of an image processing apparatus according to a second embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

[First Embodiment]
The image display device according to the first embodiment of the present invention and the image processing device that controls the image display device are applied to, for example, the following image display system.

  FIG. 1 is a block diagram showing a configuration example of an image display system according to the first embodiment of the present invention.

  The image display system 10 can include an image signal generation device 20, an image processing device 100, and an image display device 200. The image signal generation device 20 generates an image signal corresponding to an image (content) to be displayed on the image display device 200, and outputs the image signal to the image processing device 100 as an input image signal of the image processing device 100. The image processing apparatus 100 receives the image signal from the image signal generation apparatus 20 and generates a control signal for controlling the image display apparatus 200 including the diffractive optical element and the light modulation element based on the image signal. The image display device 200 displays an image obtained by modulating the diffracted light obtained by diffracting the light from the light source with the diffractive optical element with the light modulation element.

  FIG. 2 is a block diagram showing a configuration example of the image display apparatus 200 according to the first embodiment of the present invention.

  The image display apparatus 200 includes a light source 210, a diffractive optical element 220 irradiated with light from the light source, and a light modulation element 230 that modulates the diffracted light generated by the diffractive optical element 220. Based on the element control signal, the diffraction characteristic of the diffractive optical element 220 is controlled. The diffractive optical element control signal is generated in the image processing apparatus 100 based on the image signal (input image signal) from the image signal generation apparatus 20.

  The diffractive optical element 220 is irradiated with light from the light source 210 as incident light, and has a function of diffracting the light from the light source 210 into a luminance distribution specified based on the diffractive optical element control signal. As such a diffractive optical element 220, for example, there is an LC (Liquid Crystal) -CGH (Computer Generated Hologram) employing a transmissive liquid crystal panel. This liquid crystal panel is obtained by sealing liquid crystal, which is an electro-optical material, in a pair of transparent glass substrates. For example, a diffractive optical from the image processing apparatus 100 using a polysilicon thin film transistor (TFT) as a switching element. The incident light is diffracted into a diffraction pattern specified by the element control signal.

  The light modulation element 230 is irradiated with diffracted light from the diffractive optical element 220, and modulates the light transmission rate (transmittance, modulation rate) for each pixel based on the image signal from the image processing apparatus 100. As such a light modulation element 230, a light valve composed of a transmissive liquid crystal panel is employed. The liquid crystal panel is a liquid crystal panel, which is an electro-optical material, sealed and encapsulated in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element, and the light of each pixel corresponding to an image signal from the image processing apparatus 100 is used. Modulate the pass rate of.

  In the first embodiment, since the diffractive optical element 220 is provided and the diffracted light obtained by diffracting the light from the light source by the diffractive optical element 220 is modulated, the light source 210 uses the electroluminescence effect and is coherent. A coherent light source such as a high light emitting diode (LED) or a coherent laser light source is preferable, but a coherent light source is more preferable. In the following description, it is assumed that a laser light source that generates laser light is employed as the light source 210.

  In such an image display device 200, more specifically, the light source 210 includes a plurality of light sources 210R, 210G, 210B (R light source 210R, G light sources 210G, B provided for each color component in the RGB color space. The light modulation element 230 is also provided for each color component of the RGB color space. The light modulation elements 230R, 230G, and 230B (the R light modulation element 230R, the G light modulation element 230G, B light modulation element 230B). On the other hand, the diffractive optical element 220 is shared by the plurality of light sources 210R, 210G, and 210B, and is irradiated with light from the plurality of light sources 210R, 210G, and 210B.

  The R light source 210R generates red laser light having a wavelength of R component light among the three primary colors RGB. The G light source 210G generates green laser light having the wavelength of the G component light among the three primary colors RGB. The B light source 210B generates blue laser light having the wavelength of the B component light among the three primary colors RGB. The R light modulation element 230R modulates the diffracted light obtained by diffracting the red laser light from the R light source 210R by the diffractive optical element 220. The G light modulation element 230G modulates diffracted light obtained by diffracting the green laser light from the G light source 210G by the diffractive optical element 220. The B light modulation element 230B modulates the diffracted light obtained by diffracting the blue laser light from the B light source 210B by the diffractive optical element 220. By adopting such a configuration, it is only necessary to provide one diffractive optical element 220 for the light sources of the three primary colors of RGB, and the cost of the image display apparatus 200 can be reduced.

  2 further includes mirrors 240R, 240G, 240B, dichroic mirrors 242, 244, mirrors 246, 248, 250, relay lenses 252, 254, collimating lenses 256R, 256G, 256B, dichroic prism 258, A projection lens 260 can be included.

  The mirror 240R totally reflects the red laser light from the R light source 210R and guides the diffractive optical element 220 to irradiate the laser light. The mirror 240G totally reflects the green laser light from the G light source 210G and guides the diffractive optical element 220 to irradiate the laser light. The mirror 240B totally reflects the blue laser light from the B light source 210B and guides the diffractive optical element 220 to irradiate the laser light. The diffractive optical element 220 diffracts the laser light from the light sources 210R, 210G, and 210B into a luminance distribution specified by the diffractive optical element control signal.

  Here, the diffractive optical element 220 in the first embodiment will be described with reference to FIGS. In the following description, it is assumed that LC-CGH is adopted as the diffractive optical element 220.

  FIG. 3 shows a schematic plan view of the diffractive optical element 220 in the first embodiment.

  FIG. 4 is a schematic cross-sectional view taken along the line AA of the diffractive optical element 220 in FIG.

  FIG. 5 shows an explanatory diagram of the function of the diffractive optical element 220 in the first embodiment. In FIG. 5, the vertical axis indicates the intensity of each pixel on the incident light irradiation surface of the diffractive optical element 220 and the intensity of each pixel on the outgoing light emission surface.

  The LC-CGH as the diffractive optical element 220 can change the refractive index of transmitted light for each pixel of the display image. The image processing apparatus 100 generates a diffractive optical element control signal based on a diffraction pattern that designates a refractive index for each pixel as shown in FIG. The diffractive optical element control signal from the image processing apparatus 100 is supplied to the LC-CGH. In LC-CGH, an applied voltage is supplied to each pixel based on a diffractive optical element control signal, and the refractive index of light transmitted through each pixel changes.

  The diffraction pattern is generated, for example, by performing predetermined arithmetic processing on the image signal (luminance component) of the image. As this arithmetic processing, for example, there is a known iterative Fourier method. The image processing apparatus 100 generates a diffraction pattern by performing an iterative Fourier method on the luminance component of the image signal, and generates a diffractive optical element control signal corresponding to the diffraction pattern.

  As a result, the refractive index changes for each LC-CGH pixel, and a phase difference occurs in the outgoing light transmitted through the LC-CGH. Thus, the outgoing light having the phase difference interferes to generate an intensity distribution of the outgoing light. For this reason, by preparing a desired diffraction pattern, as shown in FIG. 5, the area of the predetermined area is compared to the other areas, for example, only the predetermined area has an intensity with respect to the intensity distribution of the incident light. Thus, an intensity distribution (luminance distribution) of the emitted light having a high intensity can be obtained.

  In this case, since the incident light is merely diffracted by the diffractive optical element 220, the amount of incident light can be used for other parts in the image, so that the light use efficiency can be improved. .

  Returning to FIG. 2, the description will be continued. The diffracted light from the diffractive optical element 220 having the above-described function is applied to the dichroic mirror 242.

  The dichroic mirror 242 reflects the light of the R component color among the diffracted light by the diffractive optical element 220 and guides it to the mirror 246 and transmits the light of the G component and B component colors. The mirror 246 totally reflects the light reflected by the dichroic mirror 242 and guides it to the collimating lens 256R. The collimating lens 256R converts the incident light into parallel light and outputs the parallel light to the R light modulation element 230R. Based on the image signal from the image processing apparatus 100, the R light modulation element 230R optically modulates the parallel light from the collimating lens 256R and outputs it to the dichroic prism 258.

  The dichroic mirror 244 totally reflects the G component light out of the light transmitted through the dichroic mirror 242, guides it to the parallelizing lens 256G, and transmits the B component color light. The collimating lens 256G converts the incident light into parallel light and outputs the parallel light to the G light modulation element 230G. Based on the image signal from the image processing apparatus 100, the G light modulation element 230G optically modulates the parallel light from the collimating lens 256G and outputs it to the dichroic prism 258.

  The mirror 248 totally reflects the B component light transmitted through the dichroic mirror 244 and guides it to the mirror 250. The mirror 250 totally reflects the light from the mirror 248 and guides it to the collimating lens 256B. The collimating lens 256B converts the incident light into parallel light and outputs the parallel light to the B light modulation element 230B. The B light modulation element 230 </ b> B modulates the parallel light from the parallelizing lens 256 </ b> B based on the image signal from the image processing apparatus 100 and outputs the light to the dichroic prism 258. Since the optical path length of the B component light transmitted through the dichroic mirror 244 is different from the optical path lengths of the other R component and G component light, the relay lenses 252 and 254 cause the color components between the light source and the light modulation element. Correct the distance difference as much as possible.

  The dichroic prism 258 has a function of outputting combined light obtained by combining incident light from the light modulation elements 230R, 230G, and 230B as outgoing light. The projection lens 260 is a lens that enlarges and forms an output image on a screen (not shown).

  As described above, in the image display device 200 according to the first embodiment, the diffractive optical element is provided between the light source and the light modulation element. Therefore, it is possible to display an image by optically modulating the diffracted light obtained by diffracting the light from the light source into a desired luminance distribution with an image signal, and the amount of light from the light source can be used for other parts in the image. , Can improve the light utilization efficiency. Therefore, according to the first embodiment, the amount of heat generated by the image display device 200 can be suppressed, and the cost and power consumption can be reduced by reducing the number of components.

  Further, according to the first embodiment, since the light amount of the entire screen is not adjusted uniformly, for example, even when a bright spot (light source or glossy part) exists in the image, the brightness of the bright spot is reduced. It is possible to suppress the occurrence of so-called black float.

  Furthermore, there is a case where the content is displayed by providing so-called black belt portions at the upper and lower portions in the screen due to a mismatch between the aspect ratio of the display image of the image display device 200 and the aspect ratio of the content image. According to the embodiment, since the light amount of the entire screen is not adjusted uniformly, the luminance of the black belt portion does not vary depending on the image to be displayed. For this reason, it is possible to avoid a situation in which an unnatural image whose luminance varies according to a change in the image that should be displayed with a constant luminance is displayed.

  Furthermore, according to the first embodiment, the output of the light source can be reduced to the maximum according to the input image signal without degrading the quality of the image. The power consumption can be reduced.

  Next, the image processing apparatus 100 according to the first embodiment in which the diffractive optical element is provided as described above and control is performed so that the reduced light amount is used in other parts of the image will be described.

  FIG. 6 is a block diagram illustrating a configuration example of the image processing apparatus 100 according to the first embodiment. In FIG. 6, in order to facilitate understanding of the configuration of the image processing apparatus 100, the main part of the image display apparatus 200 of FIG. In FIG. 6, the same parts as those in FIG. 1 or FIG.

  The image processing apparatus 100 receives the image signal generated by the image signal generation apparatus 20 of FIG. 1 as an input image signal. Then, the image processing apparatus 100 controls, based on the input image signal, a control signal (image signal) for controlling the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B of the image display apparatus 200, A diffractive optical element control signal for controlling the diffractive optical element 220 of the image display device 200 and a control signal for controlling the R light source 210R, the G light source 210G, and the B light source 210B of the image display device 200 are generated. Output for.

  The image processing apparatus 100 includes a diffractive optical element control unit 110 for controlling the diffractive optical element 220 of the image display apparatus 200, and a light modulation element 230 (R light modulation element 230R, G light modulation element) of the image display apparatus 200. 230G, and the light modulation element controller 120 for controlling the light modulation element 230B for B). The diffractive optical element control unit 110 generates a diffractive optical element control signal for controlling the diffraction characteristics of the diffractive optical element 220 based on the input image signal. The light modulation element control unit 120 controls the modulation characteristics of the light modulation elements 230 (R light modulation element 230R, G light modulation element 230G, and B light modulation element 230B) based on the input image signal.

  By so doing, the diffractive optical element 220 can diffract light from the light source into a luminance distribution corresponding to the input image signal. Then, the diffracted light is modulated based on the input image signal, thereby realizing image display. This makes it possible to control so that light from a light source that is originally focused to represent a dark part of an image can be used as light of another part in the image.

  More specifically, the diffractive optical element control unit 110 is based on a diffraction pattern calculation unit (a diffraction pattern generation unit in a broad sense) 112 that generates a diffraction pattern of the diffractive optical element 220 based on an input image signal, and the diffraction pattern. The diffractive optical element drive unit 114 controls the diffractive optical element 220, and the diffractive optical element control unit 110 controls the diffractive optical element 220 based on the diffraction pattern. The diffraction pattern calculation unit 112 can generate a diffraction pattern by performing a known iterative Fourier method on the input image signal.

  Thereby, it is possible to simplify the processing for using the light from the light source that is originally focused to express the dark part of the image as the light of the other part in the image by using the diffraction pattern of the diffractive optical element 220. It becomes like this.

  More specifically, the diffractive optical element control unit 110 includes an illumination distribution calculation unit 116 that calculates an ideal illumination distribution (illumination distribution in a broad sense) of light irradiated to the light modulation element based on the input image signal. The pattern calculation unit 112 generates a diffraction pattern corresponding to this ideal illumination distribution. That is, the diffraction pattern is a pattern for realizing an ideal illumination distribution. Therefore, it is desirable that the light modulation element control unit 120 controls the light modulation element based on the illumination distribution obtained from the diffraction pattern generated by the diffraction pattern calculation unit 112. However, since the diffraction pattern is generated based on the ideal illumination distribution as will be described later, the light modulation element may be controlled based on the ideal illumination distribution for the purpose of simplifying the processing.

  On the other hand, the light modulation element control unit 120 includes a transmittance calculation unit 122 and a light modulation element driving unit 124. The transmittance calculator 122 calculates the transmittance of each of the R light modulator 230R, the G light modulator 230G, and the B light modulator 230B. The transmittance calculation unit 122 calculates the transmittance of each light modulation element based on the luminance distribution of the input image signal and the illumination distribution (ideal illumination distribution or actual illumination distribution obtained from the diffraction pattern corresponding to the ideal illumination distribution). To do. The light modulation element driving unit 124 controls each of the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B so that the transmittance obtained by the transmittance calculation unit 122 is obtained.

  Further, the image processing apparatus 100 can include a light source driving unit 130. The light source driving unit 130 controls the intensity of light from the light sources (the R light source 210R, the G light source 210G, and the B light source 210B) irradiated to the diffractive optical element 220. In the first embodiment, since one diffractive optical element 220 is shared by a plurality of color components, the light source driving unit 130 adjusts the intensity of light from the plurality of light sources provided for each color component. Control each light source.

  The image processing apparatus 100 can further include a gamma conversion unit 140 and a laser output calculation unit 150.

  The gamma conversion unit 140 performs processing for converting the signal format of the input image signal. In the first embodiment, in order to control the illumination distribution, the transmittance, and the intensity of the light source based on the luminance distribution, the gamma conversion unit 140 converts, for example, an input image signal in RGB format into luminance. The image signal after the gamma conversion by the gamma conversion unit 140 is output to the light modulation element control unit 120 and the laser output calculation unit 150.

  The laser output calculation unit 150 calculates the outputs of the laser light sources constituting the R light source 210R, the G light source 210G, and the B light source 210B based on the image signal converted into the luminance component by the gamma conversion unit 140. The transmittance calculation unit 122 obtains the transmittance using the luminance distribution of the input image signal obtained by the laser output calculation unit 150. In addition, the illumination distribution calculation unit 116 calculates the illumination distribution of light from the light source irradiated on the light modulation element, using the luminance distribution of the input image signal obtained by the laser output calculation unit 150. The light source driving unit 130 drives the light source based on the luminance distribution of the input image signal obtained by the laser output calculation unit 150.

  FIG. 7 shows a block diagram of a configuration example of a main part of the image processing apparatus 100 of FIG. In FIG. 7, the same parts as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

FIG. 7 illustrates a configuration example of the diffraction pattern calculation unit 112. The diffraction pattern calculation unit 112 includes an iterative Fourier calculation unit 180 and a fast Fourier transform (FFT) calculation unit 182. The iterative Fourier computation unit 180 obtains a diffraction pattern H (x, y) for each pixel by _performing iterative Fourier computation on the ideal illumination distribution L _ideal (x, y) obtained by the illumination distribution calculation unit 116.

  The diffraction pattern H (x, y) obtained by the iterative Fourier calculation unit 180 is output to the FFT calculation unit 182 and the diffractive optical element driving unit 114.

The FFT calculation unit 182 performs an FFT calculation on the diffraction pattern for one screen using the diffraction pattern H (x, y) obtained by the iterative Fourier calculation unit 180, thereby obtaining an actual illumination distribution L _real ( x, y) is obtained. The actual illumination distribution L _real (x, y) is output to the transmittance calculation unit 122. The transmittance calculation unit 122 obtains the transmittance of the light modulation element using the actual illumination distribution L _real (x, y).

  Thus, in the first embodiment, since the diffractive optical element 220 shared by the RGB color components is provided, the intensity of light from the light source of each color component irradiated to the diffractive optical element 220 is made constant, and each color component In this case, the light from the light source that is originally focused to express the dark part of the image can be obtained without providing the diffractive optical element 220 for each color component. It becomes possible to control the image display device 200 that is used as the light of other parts in the image.

  Next, an operation example of the image processing apparatus 100 having the configuration shown in FIGS. 6 and 7 will be described.

  FIG. 8 shows a flowchart of a processing example of the image processing apparatus 100 according to the first embodiment.

  First, the image signal generated by the image signal generation device 20 is input to the image processing device 100 as an input image signal (step S10). Here, the input image signal is described as an RGB format signal, but the input image signal according to the present invention is not limited to an RGB format signal. For example, when the input image signal is a signal in a format other than the RGB format, when the input image signal is input to the image processing apparatus 100, the processing described below is performed by converting the input image signal into an RGB format signal. Can be realized.

Next, the gamma conversion unit 140 of the image processing apparatus 100 converts the input image signal in the RGB format into luminance Y _R , Y _G , Y _B for each color component (step S12). More specifically, the gamma conversion unit 140 obtains normalized luminances Y _R , Y _G , and Y _B for each color component for each pixel according to the following equation.

In the above equation, (x, y) is the coordinate position of the pixel in the image, R is the luminance signal of the R component of the pixel, R _max is the maximum value of the luminance signal of the R component, and γ is a constant representing the gradation characteristics. Show. Note that γ is determined by the standard of the image signal, and has the same value (usually 1.8 to 2.4) for the R component, the G component, and the B component. Such luminances Y _R (x, y), Y _G (x, y), and Y _B (x, y) are supplied to the light modulation element control unit 120 and the laser output calculation unit 150.

Subsequently, the laser output calculator 150 uses the luminances Y _R (x, y), Y _G (x, y), and Y _B (x, y) obtained by the gamma converter 140 for the R light sources 210R and G. The laser output P of each light source of the light source 210G and the B light source 210B is obtained (step S14). More specifically, the laser output calculation unit 150 obtains the laser output P so that each light source is the same according to the following equation and the output is the minimum necessary for displaying the input image.

In the above equation, N represents the number of pixels of the input image signal (for example, N = x _max × y _max ), and max [] represents the maximum value in []. That is, the laser output P is a value obtained by obtaining a maximum value of the highest luminance in RGB for each pixel and integrating the obtained maximum values in the screen and averaging them. Therefore, the laser output P has a value of 0 to 1, and is output to the diffractive optical element control unit 110, the light modulation element control unit 120, and the light source driving unit 130.

Subsequently, in the illumination distribution calculation unit 116 of the diffractive optical element control unit 110, an ideal illumination distribution L _ideal (x, y) is obtained (step S16). More specifically, the illumination distribution calculation unit 116 irradiates the light modulation element with the illumination distribution L _ideal (x, y) using the laser output P, Y _max (x, y) for each pixel according to the following equation. )

The illumination distribution L _ideal (x, y) obtained by the above equation is output to the diffraction pattern calculation unit 112.

The diffraction pattern calculation unit 112 calculates a diffraction pattern H (x, y) from the illumination distribution L _ideal (x, y) (step S18). More specifically, the diffraction pattern calculation unit 112 performs diffraction on the illumination distribution L _ideal (x, y) by performing predetermined arithmetic processing such as an iterative Fourier method for each pixel as shown in the following equation. A pattern H (x, y) is calculated.

  In the above equation, a predetermined calculation process such as an iterative Fourier method is represented by a function G. The diffraction pattern H (x, y) calculated in this way is output to the diffractive optical element driving unit 114.

Further, the diffraction pattern calculation unit 112 obtains the actual illumination distribution L _real (x, y) using the diffraction pattern H (x, y) obtained in step S18 (step S20). More specifically, as shown in the following equation, the diffraction pattern calculation unit 112 uses a diffraction pattern H (x, y) obtained in step S18 to perform a predetermined process such as FFT on the diffraction pattern for one screen. An actual illumination distribution L _real (x, y) is obtained by performing arithmetic processing.

In the above equation, a function for obtaining an actual illumination distribution for each pixel by performing FFT on a predetermined calculation process such as Fourier transform over all pixels of one screen is represented by F. The actual illumination distribution L _real (x, y) obtained in this way is output to the transmittance calculation unit 122.

Next, the transmittance calculation unit 122 of the light modulation element control unit 120 determines the brightness Y _R (x, y), Y _G (x, y), Y _B (x, y) obtained in step S12 and the step S20. From the obtained actual illumination distribution L _real (x, y), the transmittances T _R (x, y), T _G (x, y), and T _B (x, y) of the light modulation elements of the respective color components are obtained ( Step S22).

The transmittances T _R (x, y), T _G (x, y), and T _B (x, y) obtained by the above equation are output to the light modulation element driving unit 124.

  Then, the light source driving unit 130 drives each light source based on the laser output P obtained in step S14 so that the R light source 210R, the G light source 210G, and the B light source 210B have the same intensity (step). S24).

Further, the diffractive optical element driving unit 114 generates a diffractive optical element control signal for controlling the diffractive optical element 220 based on the diffraction pattern H (x, y) obtained in step S18, and outputs the diffractive optical element control signal to the diffractive optical element 220. (Step S26). Thus, the light output from each of the R light source 210R, the G light source 210G, and the B light source 210B is diffracted when passing through the diffractive optical element 220, and the R light modulation element 230R and the G light modulation The illumination distribution L _real (x, y) is realized on each light modulation element of the element 230G and the B light modulation element 230B.

  Subsequently, the light modulation element driving unit 124 has the transmittance obtained in step S22 for each of the light modulation elements 230R, 230G, and 230B. Each light modulation element is driven (step S28). Thereby, the light applied to the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B is modulated, and an image is output.

  Thereafter, when there is an input image signal to be processed next (step S30: Y), the process returns to step S10 to continue the processing. On the other hand, when there is no input image signal to be processed next (step S30: N), the series of processing ends (end).

  Note that the processing of the image processing apparatus 100 in the first embodiment may be realized by hardware such as a gate array or a dedicated circuit, or may be realized by software processing.

  FIG. 9 shows a block diagram of a hardware configuration example of the image processing apparatus 100 according to the first embodiment.

  6 includes a central processing unit (CPU) 300, a program memory 310, an interface (I / F) circuit 320, a frame memory 330, and a light modulation element driving circuit. 340, a diffractive optical element driving circuit 350, and a light source driving circuit 360 may be included. In the image processing apparatus 100, the CPU 300 electrically connects the program memory 310, the I / F circuit 320, the frame memory 330, the light modulation element driving circuit 340, the diffractive optical element driving circuit 350, and the light source driving circuit 360 via the bus 370. Connected to.

  The CPU 300 controls each part of the program memory 310, the I / F circuit 320, the frame memory 330, the light modulation element driving circuit 340, the diffractive optical element driving circuit 350, and the light source driving circuit 360 via the bus 370. The program memory 310 stores a program corresponding to the control content of the CPU 300. The I / F circuit 320 performs interface processing with the image signal generation device 20 and receives an image signal from the image signal generation device 20 via the input terminal TM1. The frame memory 330 stores image signals and also functions as a working memory.

  The light modulation element driving circuit 340 outputs an image signal and a control signal via the output terminal TM2 according to the control contents of the CPU 300, and outputs the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B. Drive control is performed. The diffractive optical element drive circuit 350 outputs a control signal via the output terminal TM3 in accordance with the control contents of the CPU 300, and controls the diffraction characteristics of the diffractive optical element 220. The light source driving circuit 360 performs control to change the light emission intensity of the R light source 210R, the G light source 210G, and the B light source 210B by outputting a control signal via the output terminal TM4 in accordance with the control contents of the CPU 300.

  As described above, the program memory 310 stores a program for realizing the processing shown in FIG. 8 in advance, and the CPU 300 reads the program stored in the program memory 310 and executes the processing corresponding to the program. Thus, the processing of the image processing apparatus 100 in the first embodiment can be realized by software processing.

  Note that the image processing apparatus 100 according to the first embodiment is not limited to the configuration illustrated in FIGS. 6 and 7.

  FIG. 10 is a block diagram illustrating a configuration example of a main part of the image processing apparatus 100 according to the modification of the first embodiment. 10, parts that are the same as those in FIG. 7 are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

The configuration of the image processing apparatus 100 according to the modification of the first embodiment is the same as that shown in FIG. However, as shown in FIG. 10, the diffraction pattern calculation unit 112 includes only the iterative Fourier calculation unit 180 and does not calculate the actual illumination distribution L _real . Then, the ideal illumination distribution L _ideal obtained by the illumination distribution calculation unit 116 is output to the transmittance calculation unit 122 as it is. The transmittance calculating unit 122 calculates the transmittance of the light modulation element using the ideal illumination distribution L _ideal obtained by the illumination distribution calculating unit 116.

  FIG. 11 is a flowchart of a processing example of the image processing apparatus 100 according to the modification of the first embodiment. In FIG. 11, the same parts as those in FIG.

The processing of FIG. 11 is different from the processing of FIG. 8 in that the illumination distribution calculation unit 116 _{obtains the} ideal illumination distribution L _ideal (x, y) in step S16, and then the diffraction pattern calculation unit 112 performs the diffraction pattern H (x, y) is obtained (step S19), and the transmittance calculation unit 112 calculates the transmittance of each light modulation element using the ideal illumination distribution L _ideal (x, y) (step S23).

That is, the ideal illumination distribution L _ideal (x, y) obtained in step S 16 is output to the diffraction pattern calculation unit 112 and the transmittance calculation unit 122. Therefore, the transmittance calculation unit 122 uses the ideal illumination distribution L _ideal (x, y) instead of the actual illumination distribution L _real (x, y) to transmit the transmittances T _R (x, y), T _G (x , Y), T _B (x, y).

According to such a modification of the first embodiment, the diffraction pattern calculation unit 112 performs a Fourier calculation on the diffraction pattern H (x, y) obtained by the iterative Fourier calculation unit 180 to perform the actual illumination distribution L. _Since it is not necessary to obtain _real (x, y), for example, when the error between the ideal illumination distribution L _ideal (x, y) and the actual illumination distribution L _real (x, y) is small, the image processing apparatus 100 Processing load can be greatly reduced.

  As described above, according to the first embodiment or the modification thereof, in the case of displaying an image by modulating the diffracted light obtained by diffracting the light from the light source into a desired luminance distribution using the image signal. The light quantity from the light source can be controlled so that it can be used for other parts in the image. Therefore, the light use efficiency in the image display device 200 can be increased. Therefore, according to the first embodiment, it is possible to provide the image processing apparatus 100 that can reduce the amount of heat generated by the image display apparatus 200 and can reduce the cost and power consumption by reducing the number of parts. .

  Further, according to the first embodiment or the modification thereof, the amount of light of the entire screen is not adjusted uniformly. For example, even when a bright spot (light source or glossy part) exists in the image, It is possible to provide the image processing apparatus 100 that performs control so as to suppress the decrease in brightness and the occurrence of so-called black floating.

  Furthermore, when the content is displayed by providing so-called black belt portions in the upper and lower portions of the screen due to a mismatch between the aspect ratio of the display image of the image display apparatus 200 and the aspect ratio of the content image, the first embodiment or According to the modification, it is possible to provide the image processing apparatus 100 that can be controlled so that the luminance of the black belt portion does not fluctuate depending on the image to be displayed.

  Furthermore, according to the first embodiment or its modification, the output of the light source can be reduced to the maximum according to the input image signal without degrading the image quality, in addition to preventing the deterioration of the image quality. Therefore, it is possible to provide the image processing apparatus 100 that can reduce the power consumption of the image display apparatus.

[Second Embodiment]
In the first embodiment, in the image display apparatus 200, the diffractive optical element 220 is configured to be shared by the R light source 210R, the G light source 210G, and the B light source 210B. It is not limited.

  FIG. 12 is a block diagram showing a configuration example of an image display system according to the second embodiment of the present invention. In FIG. 12, the same parts as those in FIG.

  The image display apparatus 200a in the second embodiment can also be applied to the image display system 10 in FIG. 1 instead of the image display apparatus 200 in FIG. The difference between the image display device 200a in the second embodiment and the image display device 200 in the first embodiment is that the diffractive optical element is shared by a plurality of color components in the first embodiment. In the second embodiment, a diffractive optical element is provided for each color component.

  In other words, the image display device 200a includes a plurality of light sources provided for each color component, and a plurality of diffractive optical elements provided for each color component, each diffractive optical element being irradiated with light from each light source of the plurality of light sources. And a plurality of light modulation elements that modulate the diffracted light generated by each diffractive optical element of the plurality of diffractive optical elements, provided for each color component, and a given diffractive optical element control signal Based on the above, the diffraction characteristics of each diffractive optical element are controlled. In FIG. 12, an R light source 210R, a G light source 210G, and a B light source 210B are provided as a plurality of light sources, and an R diffractive optical element 220R, a G diffractive optical element 220G, and a B light source are provided as a plurality of diffractive optical elements. A diffractive optical element 220B is provided, and an R light modulation element 230R, a G light modulation element 230G, and a B light modulation element 230B are provided as a plurality of light modulation elements.

  The light intensity of each of the plurality of light sources is controlled for each color component, and the modulation amount of each of the plurality of light modulation elements is controlled for each color component.

  In FIG. 12, the R diffractive optical element 220R is irradiated with the light from the R light source 210R as incident light, and the luminance distribution designated based on the (R) diffractive optical element control signal is used for the R light. It has a function of diffracting light from the light source 210R. The G diffractive optical element 220G is irradiated with the light from the G light source 210G as incident light, and the luminance distribution specified based on the (G) diffractive optical element control signal has a luminance distribution from the G light source 210G. It has a function to diffract light. The B diffractive optical element 220B is irradiated with light from the B light source 210B as incident light, and the luminance distribution specified based on the (B) diffractive optical element control signal is changed from the B light source 210B. Has the function of diffracting the light.

  As the R diffractive optical element 220R, the G diffractive optical element 220G, and the B diffractive optical element 220B, for example, there is an LC-CGH employing a liquid crystal panel. In this liquid crystal panel, liquid crystal, which is an electro-optical material, is hermetically sealed in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element, and diffraction is specified by a diffractive optical element control signal from an image processing apparatus. The pattern diffracts incident light.

  The R light modulation element 230R is irradiated with diffracted light from the R diffractive optical element 220R. Based on the (R) image signal from the image processing apparatus, the light transmission rate (transmittance, Modulation). The G light modulation element 230G is irradiated with diffracted light from the G diffractive optical element 220G, and based on the (G) image signal from the image processing apparatus, the light transmission rate (transmittance, Modulation). The B light modulation element 230B is irradiated with the diffracted light from the B diffractive optical element 220B. Based on the (B) image signal from the image processing apparatus, the light transmittance (transmittance, Modulation).

  As the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B, a light valve composed of a transmissive liquid crystal panel is employed. A liquid crystal panel is a liquid crystal panel, which is an electro-optical material, sealed and encapsulated in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element, and the light of each pixel corresponding to an image signal from an image processing apparatus. Modulate the pass rate.

  Also in the second embodiment, the R light source 210R, the G light source 210G, and the B light source 210B are preferably coherent light sources such as LEDs or laser light sources utilizing the electroluminescence effect, but more preferably. A coherent light source is desirable.

  In FIG. 12, the collimating lens 256R converts the diffracted light from the R diffractive optical element 220R into parallel light and outputs the parallel light to the R light modulating element 230R. The R light modulation element 230R modulates the parallel light from the collimating lens 256R based on the R image signal from the image processing device and outputs the light to the dichroic prism 258. The collimating lens 256G makes the diffracted light by the G diffractive optical element 220G parallel light and outputs it to the G light modulating element 230G. The G light modulation element 230G optically modulates the parallel light from the collimating lens 256G based on the G image signal from the image processing apparatus and outputs the light to the dichroic prism 258. The collimating lens 256B converts the diffracted light from the B diffractive optical element 220B into parallel light and outputs the parallel light to the B light modulating element 230B. The B light modulation element 230 </ b> B modulates the parallel light from the collimating lens 256 </ b> B based on the B image signal from the image processing apparatus and outputs the light to the dichroic prism 258.

  The dichroic prism 258 has a function of outputting combined light obtained by combining incident light from the light modulation elements 230R, 230G, and 230B as outgoing light. The projection lens 260 is a lens that enlarges and forms an output image on a screen (not shown).

  FIG. 13 is a block diagram illustrating a configuration example of the image processing apparatus according to the second embodiment. In FIG. 13, in order to facilitate understanding of the configuration of the image processing apparatus, the main part of the image display apparatus 200a of FIG. 12 is also shown. In FIG. 13, the same parts as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  The image processing apparatus 100a in the second embodiment can also be applied to the image display system 10 in FIG. 1 instead of the image processing apparatus 100 in FIG. The difference between the image processing apparatus 100a in the second embodiment and the image processing apparatus 100 in the first embodiment is that the intensity of the light source is made uniform for each color component since the first embodiment has one diffractive optical element. In contrast, in the second embodiment, the intensity of the light source, the diffraction characteristics of the diffractive optical element, and the modulation amount of the light modulation element can be controlled for each color component.

Therefore, the laser output calculation unit 150a can obtain the laser outputs P _R , P _G , and P _B of each light source for each color component. The illumination distribution calculation unit 116a can also obtain the ideal illumination distribution LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) for each color component. Furthermore, the diffraction pattern calculation unit 112a can also obtain diffraction patterns H _R (x, y), H _G (x, y), and H _B (x, y) for each color component. Then, the diffractive optical element driving unit 114a controls the diffraction characteristics of the diffractive optical element provided for each color component, using the diffraction pattern obtained for each color component by the diffraction pattern calculating unit 112a. Similarly, the transmittance calculating unit 122a also calculates the transmittance for each color component by using the laser output obtained for each color component.

  The diffraction pattern calculation unit 112a has the same configuration as that in FIG. 7, and can obtain a diffraction pattern and an actual illumination distribution for each color component.

  The image processing apparatus 100a according to the second embodiment includes a light source driving unit 130a that controls the intensity of light from a light source irradiated on the diffractive optical element, and a diffractive optical element is provided for each color component. In this case, the light source driving unit 130a can control the intensity of light from the light source independently for each color component.

  FIG. 14 shows a flowchart of a processing example of the image processing apparatus 100a in the second embodiment.

  First, the image signal generated by the image signal generation device 20 is input to the image processing device 100a as an input image signal (step S40). Here, the input image signal is described as an RGB format signal, but the input image signal according to the present invention is not limited to an RGB format signal. For example, when the input image signal is a signal in a format other than the RGB format, when the input image signal is input to the image processing apparatus 100a, the processing described below is performed by converting the input image signal into an RGB format signal. Can be realized.

Next, the gamma conversion unit 140 of the image processing apparatus 100a converts the input image signal in RGB format into luminance Y _R , Y _G , Y _B for each color component (step S42). More specifically, the gamma conversion unit 140 obtains normalized luminances Y _R , Y _G , and Y _B for each color component for each pixel. This process is the same as step S12 in FIG.

Subsequently, the laser output calculation unit 150a calculates R for each color component from the luminances Y _R (x, y), Y _G (x, y), Y _B (x, y) obtained by the gamma conversion unit 140. The laser outputs P _R , P _G , and P _B of the light sources 210R, 210G, and 210B are obtained (step S44). More specifically, the laser output calculation unit 150a obtains the laser outputs P _R , P _G , and P _B of each light source necessary for displaying the input image for each color component according to the following equation.

In the above equation, N is the number of pixels of the input image signal (for example, N = x _max × y _max ), and Y _R (x, y), Y _G (x, y), Y _B (x, y) is This is the luminance of each color component obtained in step S42. These laser outputs P _R , P _G , and P _B are output to the diffractive optical element control unit 110a, the light modulation element control unit 120, and the light source driving unit 130.

Subsequently, an ideal illumination distribution LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) are obtained for each color component in the illumination distribution calculation unit 116a of the diffractive optical element control unit 110a. (Step S46). More specifically, the illumination distribution calculation unit 116a performs laser output P _R , P _G , P _B , Y _R (x, y), Y _G (x, y) in units of pixels for each color component according to the following equation. ), Y _B (x, y), the illumination distributions LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) to be irradiated on the light modulation element are obtained. The illumination distribution LR _ideal (x, y) is an ideal illumination distribution for R, LG _ideal (x, y) is an ideal illumination distribution for G, and LB _ideal (x, y) is an ideal illumination distribution for B.

The illumination distributions LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) obtained by the above equation are output to the diffraction pattern calculation unit 112a.

Subsequently, the diffraction pattern calculation unit 112a determines the diffraction pattern H _R (x, y) from the illumination distributions LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) for each color component. , H _G (x, y), H _B (x, y) are calculated (step S48). More specifically, the diffraction pattern calculation unit 112a performs, for each pixel, the illumination distribution LR _ideal (x, y), LG _ideal (x, y), and LB _ideal (x, y) as shown in the following equation. The diffraction patterns H _R (x, y), H _G (x, y), and H _B (x, y) are calculated by performing predetermined arithmetic processing such as an iterative Fourier method. The diffraction pattern H _R (x, y) is an R diffraction pattern, H _G (x, y) is a G diffraction pattern, and H _B (x, y) is a B diffraction pattern.

In the above equation, a predetermined calculation process such as an iterative Fourier method is represented by a function G. The diffraction patterns H _R (x, y), H _G (x, y), and H _B (x, y) calculated in this way are output to the diffractive optical element driving unit 114a.

Thereafter, the diffraction pattern calculation unit 112a uses the diffraction patterns H _R (x, y), H _G (x, y), and H _B (x, y) obtained in step S48 to calculate the actual illumination distribution LR _real ( x, y), LG _real (x, y), and LB _real (x, y) are obtained (step S50). More specifically, as shown in the following equation, the diffraction pattern calculation unit 112a calculates the diffraction patterns H _R (x, y), H _G (x, y), H _B (x, y) obtained in step S48. Is used to perform a predetermined calculation process such as Fourier transform on the diffraction pattern for one screen, so that the actual illumination distributions LR _real (x, y), LG _real (x, y), LB _real (x, y) is determined. The illumination distribution LR _real (x, y) is the actual illumination distribution for R, LG _real (x, y) is the actual illumination distribution for G, and LB _real (x, y) is the actual illumination distribution for B. is there.

In the above equation, a function for obtaining an actual illumination distribution for each pixel by performing FFT on a predetermined calculation process such as Fourier transform over all pixels of one screen is represented by F. The actual illumination distributions LR _real (x, y), LG _real (x, y), and LB _real (x, y) thus obtained are output to the transmittance calculation unit 122a.

Next, the transmittance calculation unit 122a of the light modulation element control unit 120 determines the luminances Y _R (x, y), Y _G (x, y), Y _B (x, y) obtained in step S42 and in step S50. From the obtained actual illumination distributions LR _real (x, y), LG _real (x, y), and LB _real (x, y), the transmittances T _R (x, y) and T _G of the light modulation elements of the respective color components. (X, y) and T _B (x, y) are obtained (step S52).

The transmittances T _R (x, y), T _G (x, y), and T _B (x, y) obtained by the above equation are output to the light modulation element driving unit 124.

The light source driving unit 130a controls the intensities of the R light source 210R, the G light source 210G, and the B light source 210B for each color component based on the laser outputs P _R , P _G , and P _B obtained in step S44. Then, each light source is driven (step S54).

Furthermore, the diffractive optical element driving unit 114a performs the R diffractive optical element 220R based on the diffraction patterns H _R (x, y), H _G (x, y), and H _B (x, y) obtained in step S48. A diffractive optical element control signal for controlling the G diffractive optical element 220G and the B diffractive optical element 220B is generated and output to each diffractive optical element (step S56). Thus, the light output from each of the R light source 210R, the G light source 210G, and the B light source 210B is transmitted through the R diffractive optical element 220R, the G diffractive optical element 220G, and the B diffractive optical element 220B. Diffracted and the illumination distributions LR _real (x, y), LG _real (x, y), R light modulation element 230R, G light modulation element 230G, and B light modulation element 230B LB _real (x, y) is realized.

  Subsequently, the light modulation element driving unit 124 sets the transmittance obtained in step S52 for each of the light modulation elements 230R, 230G, and 230B. Each light modulation element is driven (step S58). Thereby, the light applied to the R light modulation element 230R, the G light modulation element 230G, and the B light modulation element 230B is modulated, and an image is output.

  Thereafter, when there is an input image signal to be processed next (step S60: Y), the process returns to step S40 to continue the processing. On the other hand, when there is no input image signal to be processed next (step S60: N), the series of processing ends (end).

  Note that the processing of the image processing apparatus 100a in the second embodiment may be realized by hardware such as a gate array or a dedicated circuit, or may be realized by software processing. In this case, the hardware configuration example of the image processing apparatus 100a in the second embodiment is the same as that in FIG.

  Also in the second embodiment, in order to simplify the processing, the configuration shown in FIG. 10 may be adopted and the processing shown in FIG. 11 may be executed.

  In the second embodiment described above, a diffractive optical element is provided for each color component. That is, since the diffractive optical element is provided for each light source, the intensity of the light source can be controlled for each color component, so that the intensity of the light source for each color component does not have to be uniformed. Therefore, although the number of components increases as compared with the configuration of the first embodiment, there may be a case where even lower power consumption can be realized as compared with the first embodiment.

  The image processing device, the image display device, the image processing method, and the program according to the present invention have been described based on the above embodiments, but the present invention is not limited to each of the above embodiments, and the gist thereof The present invention can be implemented in various forms without departing from the scope of the invention, and for example, the following modifications are possible.

  (1) In each of the above embodiments, the image display device has been described as having the configuration shown in FIG. 2 or FIG. 12, but the present invention is not limited to this, and the diffractive optical element and the light modulation element Or an image processing apparatus for controlling the image display apparatus, an image processing method, and a program for controlling the image processing apparatus.

  (2) In each of the above embodiments, the diffractive optical element is described as being, for example, LC-CGH, but the present invention is not limited to this.

  (3) In each of the above-described embodiments, the light modulation element is described as a light valve composed of, for example, a transmissive liquid crystal panel. However, the present invention is not limited to this. For example, a light modulation element other than a transmissive liquid crystal panel, such as DLP (Digital Light Processing) (registered trademark), LCOS (Liquid Cristal On Silicon), or the like may be employed.

  (4) In each of the above embodiments, the image processing apparatus has been described as having the configuration shown in FIG. 6 or FIG. 13, but the present invention is not limited to this. The image processing apparatus is not limited to the one having all the blocks in FIG. 6 or FIG. 13, and may have a configuration in which a part of the image processing apparatus in FIG. 6 or 13 is omitted. For example, in the image processing apparatus of FIG. 6 or FIG. 13, the gamma conversion unit 140 may be omitted.

  (5) In each of the embodiments described above, the illumination distribution is obtained and then the diffraction pattern is obtained. However, the present invention is not limited to this.

  (6) In each of the embodiments described above, the iterative Fourier method is used as a method for obtaining a diffraction pattern. However, the present invention is not limited to an arithmetic processing method for obtaining a diffraction pattern.

  (7) In the above embodiments, the diffractive optical element control signal has been described as being generated based on the input image signal. However, the present invention is not limited to this. For example, the diffractive optical element control signal may be generated based on the shape of the screen projected by the image display device.

  (8) In each of the above-described embodiments, the present invention is an image processing apparatus and an image display apparatus that make it possible to use light from a light source focused to express a dark part of an image for other parts of the image. Although described as an image processing method and program, the present invention is not limited to this. For example, it may be a recording medium on which a program describing a processing procedure for realizing the present invention is recorded.

  DESCRIPTION OF SYMBOLS 10 ... Image display system, 20 ... Image signal generation apparatus, 100, 100a ... Image processing apparatus, 110, 110a ... Diffraction optical element control part, 112, 112a ... Diffraction pattern calculation part, 114, 114a ... Diffraction optical element drive part, 116, 116a ... Illumination distribution calculation unit, 120 ... Light modulation element control unit, 122, 122a ... Transmittance calculation unit, 124 ... Light modulation element drive unit, 130, 130a ... Light source drive unit, 140 ... Gamma conversion unit, 150, 150a ... laser output calculation unit, 180 ... iteration Fourier calculation unit, 182 ... FFT calculation unit, 200, 200a ... image display device, 210 ... light source, 210R ... light source for R, 210G ... light source for G, 210B ... light source for B, 220 ... Diffraction optical element, 220R ... R diffractive optical element, 220G ... G diffractive optical element, 220B ... B diffractive optical element, 2 DESCRIPTION OF SYMBOLS 0 ... Light modulation element, 230R ... R light modulation element, 230G ... G light modulation element, 230B ... B light modulation element, 240R, 240G, 240B, 246, 248, 250 ... Mirror, 242, 244 ... Dichroic mirror , 252,254 ... relay lens, 256R, 256G, 256B ... collimating lens, 258 ... dichroic prism, 260 ... projection lens, 300 ... CPU, 310 ... program memory, 320 ... I / F circuit, 330 ... frame memory, 340 ... Light modulating element driving circuit, 350. Diffractive optical element driving circuit, 360... Light source driving circuit, 370... Bus, TM1 .. Input terminal, TM2, TM3, TM4.

Claims (8)

A light source;
A diffractive optical element that diffracts light emitted from the light source;
A light modulation element that modulates the diffracted light diffracted by the diffractive optical element,
An image display apparatus, wherein diffraction characteristics of the diffractive optical element are controlled based on a given diffractive optical element control signal. A plurality of light sources provided for each color component;
A diffractive optical element that is shared by the plurality of light sources and diffracts the light emitted from the plurality of light sources;
A plurality of light modulation elements that are provided for each of the color components and modulate the diffracted light diffracted by the diffractive optical element,
An image display apparatus, wherein diffraction characteristics of the diffractive optical element are controlled based on a given diffractive optical element control signal. In claim 2,
The light intensity of each of the plurality of light sources is controlled to be the same,
The image display device according to claim 1, wherein a modulation amount of each of the plurality of light modulation elements is controlled for each color component. A plurality of light sources provided for each color component;
A plurality of diffractive optical elements provided for each of the color components, each diffractive optical element diffracting light emitted from each light source of the plurality of light sources;
A plurality of light modulation elements that are provided for each of the color components, and each light modulation element modulates diffracted light diffracted by each diffractive optical element of the plurality of diffractive optical elements,
An image display apparatus characterized in that diffraction characteristics of each diffractive optical element are controlled based on a given diffractive optical element control signal. In claim 4,
The light intensity of each light source of the plurality of light sources is controlled for each color component,
The image display device according to claim 1, wherein a modulation amount of each of the plurality of light modulation elements is controlled for each color component. In any one of Claims 1 thru | or 5,
The diffractive optical element control signal is:
An image display device characterized by being a signal generated based on an input image signal. In claim 6,
The diffractive optical element control signal is:
An image display device generated using a diffraction pattern corresponding to an illumination distribution of light from the light source calculated based on the input image signal. In any one of Claims 1 thru | or 7,
The light source is
An image display device that generates coherent light.