JP2005257707A - Optical modulation device, optical display device, optical modulation method and picture display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the enlargement of the dynamic range of luminance and the number of gradation, the improvement of the luminance and the quality of a display picture, and the miniaturization of a device. <P>SOLUTION: In the optical modulation device, a projection type display device 100 is equipped with a light source 10, dichroic mirrors 44a and 44b separating a light beam from the light source 10 to light beams of three primary colors RGB, a plurality of color modulation light valves on which the light beams separated by the dichroic mirrors 44a and 44b are made incident respectively and which have a plurality of pixels whose transmittance T2 can be controlled independently, a dichroic prism 48 composing the light beams from the respective color modulation light valves, a relay lens 16 forming the optical images of the respective color modulation light valves on the pixel surface of a reflection type liquid crystal light valve 50, and the reflection type liquid crystal light valve 50 on which the light beam from the relay lens 16 is made incident and which have a plurality of pixels whose reflectance T1 can be controlled independently. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for modulating light from a light source via a plurality of light modulation elements, and in particular, to expand the dynamic luminance range and the number of gradations, improve the luminance and image quality of a display image, and reduce the size of the apparatus. The present invention relates to a light modulation device, an optical display device, a light modulation method, and an image display method that are suitable for realizing the image processing.

In recent years, LCD (Liquid Crystal Display), EL, plasma display, CRT (Cathode Ray Tube), projectors, and other optical display devices have seen remarkable improvements in image quality, and the resolution and color gamut have achieved performance that is almost comparable to human visual characteristics. It is being done. However, regarding the luminance dynamic range, the reproduction range is limited to about 1 to 10 ² [nit], and the number of gradations is generally 8 bits. On the other hand, human visual perception has a luminance dynamic range perceived at a time of about 10 ⁻² to 10 ⁴ [nit], and the luminance discrimination capability is about 0.2 [nit], which is the number of gradations. Is converted to 12 bits. Looking at the display image of the current optical display device through such visual characteristics, the narrowness of the luminance dynamic range is conspicuous, and in addition, the reality and power of the display image are insufficient due to the lack of gradation in the shadow part and highlight part. Will feel unsatisfactory.

  Further, in computer graphics (hereinafter abbreviated as CG) used in movies, games, etc., display data (hereinafter referred to as HDR (High Dynamic Range) display data) that represents a luminance dynamic range and gradation number close to human vision. The movement of pursuing the reality of depiction is being mainstream. However, since the performance of the optical display device that displays it is insufficient, there is a problem that the expressive power inherent in the CG content cannot be fully exhibited.

Further, in the next OS (Operating System), the adoption of a 16-bit color space is planned, and the luminance dynamic range and the number of gradations are dramatically increased as compared with the current 8-bit color space. Therefore, it is desired to realize an optical display device that can make use of the 16-bit color space.
Among optical display devices, projection display devices such as liquid crystal projectors and DLP projectors are capable of displaying on a large screen and are effective in reproducing the reality and power of display images. In this field, the following proposals have been made to solve the above problems.

  As a projection display device with a high dynamic range, for example, there is a technique disclosed in Patent Document 1, which includes a light source, a first light modulation element that modulates luminance in the entire wavelength region of light, and a wavelength region of light. Among these, each wavelength region of the RGB three primary colors is provided with a second light modulation element that modulates the luminance of the wavelength region, and the light from the light source is modulated by the first light modulation element to form a desired luminance distribution, and its optical image Is imaged on the pixel surface of the second light modulation element, color-modulated, and second-order modulated light is projected. Each pixel of the first light modulation element and the second light modulation element is individually controlled based on the first control value and the second control value determined from the HDR display data. As the light modulation element, a transmission type light modulation element having a pixel structure or a segment structure whose transmittance can be controlled independently and capable of controlling a two-dimensional transmittance distribution is used. A typical example is a liquid crystal light valve.

  Consider a case where a light modulation element having a dark display transmittance of 0.2% and a bright display transmittance of 60% is used. With a single light modulation element, the luminance dynamic range is 60 / 0.2 = 300. Since the conventional projection display apparatus corresponds to optically arranging light modulation elements having a luminance dynamic range of 300 in series, a luminance dynamic range of 300 × 300 = 90000 can be realized. The same idea holds for the number of gradations, and an 8-bit gradation light modulation element is optically arranged in series, whereby a gradation number exceeding 8 bits can be obtained.

In addition, as a projection display device that realizes a high luminance dynamic range, for example, a projection display device disclosed in Patent Document 2 is known.
The invention described in Patent Document 2 includes a DMD (Digital Micromirror Device) in which a plurality of pixels are arranged in a line, an illumination unit that irradiates a light beam to the DMD, a processing unit that converts an input video signal into a DMD drive signal, An optical scanning unit that scans the light beam modulated by the DMD and a projection lens that projects the light beam from the light scanning unit onto the screen surface, and the illumination unit modulates the amount of irradiation light according to the input video signal.
Japanese Patent Laid-Open No. 2001-1000068 JP 2001-174919 A

FIG. 23 is a diagram illustrating a pixel surface of each pixel of the transmissive liquid crystal light valve.
In the transmissive liquid crystal light valve, transistors and signal wirings for driving pixel electrodes are provided in each pixel surface. Therefore, as shown in FIG. 23, the transmissive liquid crystal light valve is an opening (a part through which light is transmitted) in each pixel. ) Becomes a window shape, and the opening ratio is generally 60% or less.
Therefore, in the invention described in Patent Document 1, in order to ensure the brightness of the display image, the optical image of the opening of each pixel of the first light modulation element is used as the opening of the corresponding pixel of the second light modulation element. Therefore, it is necessary to perform alignment so as to form an image accurately, and high alignment accuracy is required.

FIG. 24 is a diagram showing the configuration of the optical paths of the first light modulation element and the second light modulation element in the projection display device described in Patent Document 1. Although other optical elements such as mirrors are also arranged on the actual optical path, FIG. 24 is drawn with these optical elements omitted for easy understanding of the following description.
In the optical system of FIG. 24, the first light modulation element 130 for luminance modulation is disposed on the light source side with the fly-eye lenses 112a and 112b interposed therebetween, and the color modulation is performed on the opposite side of the light source with the fly-eye lenses 112a and 112b interposed therebetween. The second light modulation element 140 is arranged. In this optical system, an optical image of the first light modulation element is formed on the second light modulation element by the fly-eye lenses 112a and 112b and the condenser lens 112d. By the way, the fly-eye lenses 112a and 112b and the condenser lens 112d are optical elements used for the purpose of uniforming the luminance distribution and have low imaging performance.

For this reason, in the invention described in Patent Document 1, it is difficult to accurately transmit the optical image of the first light modulation element to the pixel surface of the second light modulation element, and the luminance of the display image is low. There was a problem of lowering.
FIG. 25 is a diagram illustrating a pixel surface of each pixel of the reflective light modulation element.
On the other hand, a reflection type light modulation element such as a DMD can be provided with a drive unit for driving the mirror on the back surface of the mirror. Therefore, as shown in FIG. In general, the aperture ratio is 90% or more.

Patent Document 1 describes that the second light modulation element can be formed of DMD, but has the following problems.
In the optical system of FIG. 24, the partial optical image of the first light modulation element 130 for each range corresponding to each element lens constituting the fly-eye lens 112 a close to the first light modulation element 130 is a pixel of the second light modulation element 140. The image is superimposed on the surface. Therefore, in order to obtain a desired luminance distribution, this luminance distribution must be formed for each range corresponding to each element lens. By the way, the fly-eye lenses 112a and 112b are optical elements used for the purpose of uniforming the luminance distribution, and for that purpose, it is desirable that the number of element lenses is large. Then, the size of each element lens is inevitably smaller than each pixel size of the second light modulation element 140. Specifically, those having a size of about 1/3 to 1/5 are used. Now, considering that the pixels of the second light modulation element 140 and the pixels of the first light modulation element 130 have a one-to-one correspondence, the pixel density of the first light modulation element 130 is the pixel of the second light modulation element 140. 3-5 times the density is required. However, the current light modulation element (for example, a liquid crystal light valve) has a pixel density close to the upper limit of the microfabrication technology for high definition, and considering that point, the first light modulation element 130 It is difficult to achieve a pixel density of 3 to 5 times. Accordingly, the accuracy of the luminance distribution that can be formed by the first light modulation element 130 must be 3 to 5 times as coarse as the pixel density of the second light modulation element 140. Furthermore, since the optical image of each element lens is formed on the pixel surface of the second light modulation element 140 by at most two lenses, the fly-eye lens 112b and the condenser lens 12d that are far from the first light modulation element 130, Sufficient aberration correction cannot be performed and it must be considerably blurred.

On the other hand, in the invention described in Patent Document 2, since a solid-state laser or a semiconductor laser is used as a light source, there is a problem that the apparatus becomes large. In addition, when a semiconductor laser is used as the light source, there is a problem that the luminance of the display image is lowered because the light output is small.
Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and has been made to expand the luminance dynamic range and the number of gradations, improve the luminance and image quality of the display image, and the apparatus. An object of the present invention is to provide a light modulation device, an optical display device, a light modulation method, and an image display method that are suitable for realizing the downsizing of the display.

[Invention 1] In order to achieve the above object, an optical modulation device of Invention 1 comprises:
A first light modulation element that modulates light; and a second light modulation element that receives light from the first light modulation element and modulates light; and the first light modulation element and the second light modulation element A device for modulating light from a light source via
The second light modulation element is constituted by a reflection type light modulation element,
A relay lens for forming an optical image of the first light modulation element on a light receiving surface of the second light modulation element is provided on an optical path between the first light modulation element and the second light modulation element. To do.

With such a configuration, the light from the light source is first-order modulated by the first light modulation element, and the optical image of the first light modulation element is formed on the light receiving surface of the second light modulation element via the relay lens. Is done. The light from the first light modulation element is secondarily modulated by reflecting the light from the first light modulation element by the second light modulation element.
Thereby, since the light from the light source is modulated via the first light modulation element and the second light modulation element, an effect that a relatively high luminance dynamic range and gradation number can be realized is obtained. In addition, since the second light modulation element is composed of a reflective light modulation element having a high aperture ratio, the brightness of the display image can be increased to some extent even if the alignment accuracy between the first light modulation element and the second light modulation element is not high. Can be secured. Therefore, the effect that it can suppress that the brightness | luminance of a display image falls compared with the past is also acquired. Further, since the optical image of the first light modulation element is formed on the light receiving surface of the second light modulation element via the relay lens, the optical image of the first light modulation element is relatively formed on the light receiving surface of the second light modulation element. Since an image can be formed with high accuracy, relatively high-precision modulation can be performed. Accordingly, an effect that the possibility that the image quality is deteriorated can be reduced as compared with the conventional case. Furthermore, since it is not necessary to use a solid laser or a semiconductor laser as a light source, it is possible to obtain an effect that the apparatus can be reduced in size and brightness as compared with the conventional case.

Here, as the light source, any medium that generates light can be used. For example, the light source may be a light source built in an optical system such as a lamp, or may be a sun light or an indoor light. It may be an external light source. Hereinafter, the same applies to the light modulation method of the tenth invention.
In addition, the first light modulation element may have any configuration as long as it modulates light, and the structure may be, for example, a single plate type composed of a single light modulation element. In addition, a multi-plate type composed of a plurality of light modulation elements may be used. As a function, for example, the luminance of the entire wavelength region of light may be modulated, or the luminance of the specific wavelength region may be modulated for a plurality of different specific wavelength regions out of the wavelength region of light. It may be. The same applies to the optical display device of the invention 2, the light modulation method of the invention 10, and the image display method of the invention 11.

  In addition, the second light modulation element may have any configuration as long as it reflects light, and the structure may be, for example, a single plate type composed of a single light modulation element. In addition, a multi-plate type composed of a plurality of light modulation elements may be used. As a function, for example, the luminance of the entire wavelength region of light may be modulated, or the luminance of the specific wavelength region may be modulated for a plurality of different specific wavelength regions out of the wavelength region of light. It may be. Hereinafter, the same applies to the light modulation method of the tenth invention.

[Invention 2] On the other hand, in order to achieve the above object, an optical display device of Invention 2 comprises:
A light source, light separating means for separating light from the light source into light of a plurality of different specific wavelength regions, and a plurality of first light modulation elements that respectively enter the light separated by the light separating means and modulate the light A light combining means for combining the light from each of the first light modulation elements, and a second light modulation element for receiving the light from the light combining means and modulating the light, and each of the first light modulation elements, An apparatus for displaying an image by modulating light from the light source via a second light modulation element,
The second light modulation element is constituted by a reflection type light modulation element,
A relay lens for forming an optical image of each of the first light modulation elements on a light receiving surface of the second light modulation element is provided on an optical path between the light combining unit and the second light modulation element.

  With such a configuration, the light from the light source is separated into light of a plurality of specific wavelength regions by the light separating means, and each separated light from the light separating means is primarily modulated by each first light modulation element. The Next, light from each first light modulation element is combined by the light combining means, and the combined light is incident on the second light modulation element. At this time, an optical image of each first light modulation element is formed on the light receiving surface of the second light modulation element via the relay lens. Then, the light from the light combining means is secondarily modulated by reflecting the light from the light combining means by the second light modulation element.

  Thereby, since the light from the light source is modulated via the first light modulation element and the second light modulation element, an effect that a relatively high luminance dynamic range and gradation number can be realized is obtained. In addition, since the second light modulation element is composed of a reflective light modulation element having a high aperture ratio, the brightness of the display image can be increased to some extent even if the alignment accuracy between the first light modulation element and the second light modulation element is not high. Can be secured. Therefore, the effect that it can suppress that the brightness | luminance of a display image falls compared with the past is also acquired. Further, since the optical image of each first light modulation element is formed on the light receiving surface of the second light modulation element via the relay lens, the optical image of each first light modulation element is formed on the light receiving surface of the second light modulation element. Since imaging can be performed with relatively high accuracy, modulation with relatively high accuracy can be performed. Accordingly, an effect that the possibility that the image quality is deteriorated can be reduced as compared with the conventional case. Furthermore, since it is not necessary to use a solid laser or a semiconductor laser as a light source, it is possible to obtain an effect that the apparatus can be reduced in size and brightness as compared with the conventional case.

  Here, the specific wavelength region is not limited to be set for each of the RGB three primary colors, but can be arbitrarily set as necessary. However, if it is set for each of the RGB primary colors, the existing liquid crystal light valve can be used as it is, which is advantageous in terms of cost. The same applies to the image display method of the eleventh aspect.

[Invention 3] Furthermore, the optical display device of Invention 3 is the optical display device of Invention 2,
The second light modulation element is composed of a reflective liquid crystal display element.

  With such a configuration, since the second light modulation element is configured by a reflective liquid crystal display element having a high aperture ratio, even if the alignment accuracy between the first light modulation element and the second light modulation element is not high, The brightness of the display image can be secured to some extent. In addition, polarization characteristics can be maintained in light transmission between the first light modulation element and the second light modulation element. Therefore, it is possible to further suppress the decrease in the luminance of the display image.

[Invention 4] Furthermore, the optical display device of Invention 4 is the optical display device of Invention 2,
The second light modulation element is composed of DMD.
With such a configuration, since the second light modulation element is configured with DMD having a high aperture ratio, the brightness of the display image can be obtained even if the alignment accuracy between the first light modulation element and the second light modulation element is not high. Can be secured to some extent. In addition, the second light modulation element can be digitally driven.

[Invention 5] Further, the optical display device of Invention 5 is the optical display device of any one of Inventions 2 to 4,
The second light modulation element is composed of a reflective light modulation display panel that modulates light and displays an image,
The reflective light modulation display panel has a light diffusion structure.

With such a configuration, since the reflection type light modulation display panel has a light diffusion structure, light from the first light modulation element is scattered and reflected to display an image.
Thereby, the effect that it can suppress that the viewing angle of a reflection type light modulation display panel falls is acquired.

[Invention 6] Furthermore, the optical display device of Invention 6 is the optical display device of Invention 5,
The reflection type light modulation display panel has a light diffusion structure for diffusing light so as to converge substantially in a predetermined direction.

With such a configuration, the reflection type light modulation display panel has a light diffusion structure for diffusing light so as to almost converge toward a predetermined direction, so that light from the first light modulation element can be transmitted in all directions. Is scattered and reflected within a certain range.
As a result, if the reflective light modulation display panel is viewed from within a certain range, a viewing angle with almost no problem in viewing can be obtained, and the appearance brightness and the uniformity of display brightness distribution of the display image are prevented from deteriorating. The effect that it can do is acquired.

[Invention 7] Furthermore, the optical display device of Invention 7 is the optical display device of any one of Inventions 5 and 6,
An uneven portion having a light diffusion function is formed on the reflection surface of the reflection type light modulation display panel.
With such a configuration, since the uneven portion is formed on the reflection surface of the reflective light modulation display panel, the light from the first light modulation element is scattered and reflected by the uneven portion.
Thereby, the effect that it can suppress that the viewing angle of a reflection type light modulation display panel falls is acquired.

[Invention 8] The optical display device of Invention 8 is the optical display device of Invention 7,
A plurality of concavo-convex portions are formed on the reflection surface of the reflective light modulation display panel, and the cross-sectional shape of the concave portion or the convex portion in each concavo-convex portion is asymmetrical when viewed from the apex, and the center of the reflective light modulation display panel Alternatively, the degree of asymmetry is changed according to the distance from the vicinity thereof.

With such a configuration, the light from the first light modulation element is scattered and reflected by each uneven portion, and the scattered reflected light can be substantially converged in a predetermined direction due to the difference in asymmetry of each uneven portion. .
As a result, if the reflective light modulation display panel is viewed from within a certain range, a viewing angle with almost no problem in viewing can be obtained, and the appearance brightness and the uniformity of display brightness distribution of the display image are prevented from deteriorating. The effect that it can do is acquired.

[Invention 9] Furthermore, the optical display device of Invention 9 is the optical display device of any one of Inventions 5 to 8,
The reflection type light modulation display panel is provided with a Fresnel lens.
With such a configuration, the diffuse reflected light of the reflective light modulation display panel can be substantially converged in the direction of the viewer by the condensing function of the Fresnel lens.

  As a result, if the reflective light modulation display panel is viewed from within a certain range, a viewing angle with almost no problem in viewing can be obtained, and the appearance brightness and the uniformity of display brightness distribution of the display image are prevented from deteriorating. The effect that it can do is acquired.

[Invention 10] On the other hand, in order to achieve the above object, the light modulation method of Invention 10 includes:
A first modulation step for modulating light from the light source via the first light modulation element; and a second modulation step for modulating light from the first light modulation element via the second light modulation element. , A method of modulating light from the light source,
The second light modulation element is a reflective light modulation element,
An optical image of the first light modulation element is formed on a light receiving surface of the second light modulation element through a relay lens in an optical path between the first light modulation element and the second light modulation element. .
Thereby, an effect equivalent to that of the light modulation device of aspect 1 is obtained.

[Invention 11] On the other hand, in order to achieve the above object, an image display method of Invention 11 includes:
A light separation step for separating the light from the light source through a light separation means for separating the light into a plurality of different specific wavelength regions, and for each separated light from the light separation means, through the first light modulation element A first modulation step for modulating the separated light, a light synthesis step for synthesizing the separated light from each of the first light modulation elements via light synthesis means for synthesizing light, and a second light modulation element for A second modulation step of modulating the light from the light combining means, and modulating the light from the light source to display an image,
The second light modulation element is a reflective light modulation element,
An optical image of each of the first light modulation elements is formed on a light receiving surface of the second light modulation element via a relay lens in an optical path between the light combining unit and the second light modulation element.
Thereby, an effect equivalent to that of the optical display device of aspect 2 is obtained.

[Invention 12] Further, the image display method of Invention 12 is the image display method of Invention 11,
The second light modulation element is a reflective liquid crystal display element.
Thereby, an effect equivalent to that of the optical display device of aspect 3 is obtained.

[Invention 13] The image display method of Invention 13 is the image display method of Invention 11,
The second light modulation element is a DMD.
Thereby, an effect equivalent to that of the optical display device of aspect 4 is obtained.

[Invention 14] Furthermore, the image display method of Invention 14 is the image display method of any one of Inventions 11 to 13,
The second light modulation element is a reflective light modulation display panel that modulates light and displays an image,
The reflective light modulation display panel has a light diffusion structure.
Thereby, an effect equivalent to that of the optical display device of aspect 5 is obtained.

[Invention 15] Furthermore, the image display method of Invention 15 is the image display method of Invention 14,
The reflection type light modulation display panel has a light diffusion structure for diffusing light so as to converge substantially in a predetermined direction.
Thereby, an effect equivalent to that of the optical display device of aspect 6 is obtained.

[Invention 16] Furthermore, the image display method of Invention 16 is the image display method of any one of Inventions 14 and 15,
An uneven portion having a light diffusion function is formed on the reflection surface of the reflective light modulation display panel.
Thereby, an effect equivalent to that of the optical display device of aspect 7 is obtained.

[Invention 17] Further, the image display method of Invention 17 is the image display method of Invention 16,
A plurality of concavo-convex portions are formed on the reflection surface of the reflective light modulation display panel, and the cross-sectional shape of the concave portion or the convex portion in each of the concavo-convex portions is asymmetric when viewed from the apex, and the reflective light modulation display The degree of asymmetry changes according to the distance from the center of the panel or the vicinity thereof.
Thereby, an effect equivalent to that of the optical display device of aspect 8 is obtained.

[Invention 18] Furthermore, the image display method of Invention 18 is the image display method of any one of Inventions 14 to 17,
The reflection type light modulation display panel is provided with a Fresnel lens.
Thereby, an effect equivalent to that of the optical display device of aspect 9 is obtained.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 to 12 are diagrams showing a first embodiment of a light modulation device and an optical display device, and a light modulation method and an image display method according to the present invention.
In the present embodiment, the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention are applied to a projection display device 100 as shown in FIG.

First, the configuration of the projection display device 100 will be described with reference to FIG.
FIG. 1 is a block diagram illustrating a hardware configuration of the projection display apparatus 100.
As shown in FIG. 1, the projection display device 100 includes a light source 10, a luminance distribution uniformizing unit 12 that uniformizes a luminance distribution of light incident from the light source 10, and a light incident from the luminance distribution uniforming unit 12. The color modulation unit 14 that modulates the luminances of the RGB three primary colors in the wavelength region, the relay lens 16 that relays the light incident from the color modulation unit 14, and the luminance in the entire wavelength region of the light that is incident from the relay lens 16 The luminance modulation unit 18 and a projection unit 20 that projects light incident from the luminance modulation unit 18 onto a screen (not shown) are configured.

The light source 10 includes a lamp 10a such as a high-pressure mercury lamp and a reflector 10b that reflects light emitted from the lamp 10a.
The color modulation unit 14 includes three transmissive liquid crystal light valves 40R, 40G, and 40B in which a plurality of pixels whose transmittance can be independently controlled are arranged in a matrix, and five field lenses 42R, 42G, and 42B ₁ to. and 42B _3, 2 dichroic mirrors 44a, and 44b, 3 mirrors 46a, 46b, and 46c, is constituted by a dichroic prism 48. First, it lights the dichroic mirror 44a from uniform luminance distribution section 12, as well as spectral red, green and blue RGB3 primary by 44b, via the field lens 42R, 42G, and 42B ₁ ~42B ₃ and mirror 46a~46c The light enters the transmissive liquid crystal light valves 40R to 40B. The luminance of the RGB three primary colors is then modulated by the transmissive liquid crystal light valves 40R to 40B, and the modulated RGB three primary colors are synthesized by the dichroic prism 48 and emitted to the relay lens 16.

  The transmissive liquid crystal light valves 40R to 40B include a glass substrate on which pixel electrodes and switching elements such as thin film transistors and thin film diodes for driving the pixel electrodes are formed in a matrix, and a glass substrate on which a common electrode is formed over the entire surface. This is an active matrix type liquid crystal display element in which a TN liquid crystal is sandwiched between and a polarizing plate is disposed on the outer surface. The transmissive liquid crystal light valves 40R to 40B are in a normally white mode in which a white / bright (transmission) state is applied when no voltage is applied, and a black / dark (non-transmission) state is applied when a voltage is applied, or vice versa. It is driven, and the gradation between light and dark is analog controlled according to the given control value.

The dichroic prism 48 is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in an X-shaped cross section. With these dielectric multilayer films, RGB three primary colors can be synthesized.
The luminance modulation unit 18 includes a reflective liquid crystal light valve 50 in which a plurality of pixels whose reflectance can be controlled independently is arranged in a matrix and has a resolution lower than that of the transmissive liquid crystal light valves 40R to 40B, and transmits P-polarized light. The polarizing beam splitter 52 that reflects S-polarized light and the λ / 4 plate 54 for improving the contrast characteristics of the reflective liquid crystal light valve 50 are configured. First, the P-polarized component of the light flux from the relay lens 16 is incident on the reflective liquid crystal light valve 50 via the polarizing beam splitter 52 and the λ / 4 plate 54, and the polarization state in the entire wavelength region of the incident light is reflected. The light is modulated and reflected by the liquid crystal light valve 50. Then, the reflected light is incident on the polarization beam splitter 52 via the λ / 4 plate 54, and the S-polarized component (luminance-modulated light subjected to the second light modulation) of the incident light flux is transmitted via the polarization beam splitter 52. To the projection unit 20.

  The reflective liquid crystal light valve 50 is configured by disposing a silicon substrate having reflective pixel electrodes formed in a matrix on the surface and a transparent substrate having transparent electrodes disposed therebetween via a spacer, and enclosing liquid crystal therebetween. Yes. A drive circuit for driving the reflective pixel electrode is also formed on the silicon substrate. An alignment film for aligning liquid crystals in a predetermined direction is formed on the surfaces of these two substrates. The reflective liquid crystal light valve 50 is driven in a normally white mode in which a white / bright (transmission) state is applied when no voltage is applied, and a black / dark (non-transmission) state is applied when a voltage is applied, or vice versa. The gradation between light and dark is analog controlled according to the given control value.

  The luminance distribution uniformizing unit 12 includes two fly-eye lenses 12a and 12b, a polarization conversion element 12c, and a condenser lens 12d. Then, the brightness distribution of the light from the light source 10 is made uniform by the fly-eye lenses 12a and 12b, and the uniformed light is polarized by the polarization conversion element 12c in the incident polarization direction of the color modulation light valve to collect the polarized light. The light is condensed by the lens 12 d and emitted to the color modulation unit 14.

For example, the polarization conversion element 12c includes a PBS array and a half-wave plate. The half-wave plate converts incident linearly polarized light into linearly polarized light orthogonal thereto.
FIG. 2 is a diagram illustrating a configuration of the relay lens 16.
The relay lens 16 forms an optical image of each of the transmissive liquid crystal light valves 40R to 40B on the pixel surface of the reflective liquid crystal light valve 50, and is substantially symmetric with respect to the aperture stop as shown in FIG. This is an equal-magnification imaging lens composed of a front lens group and a rear lens group arranged in the lens. The front lens group and the rear lens group are configured by a plurality of convex lenses and one concave lens. However, the shape, size, arrangement interval and number of lenses, telecentricity, magnification and other lens characteristics can be appropriately changed depending on required characteristics, and are not limited to the example of FIG.

FIG. 3 is a diagram illustrating the operating principle of the relay lens 16.
As shown in FIG. 3, the relay lens 16 is typically formed with an equal-magnification image, so even if the pixel densities of the transmissive liquid crystal light valves 40R to 40B and the reflective liquid crystal light valve 50 are the same, The pixels of the transmissive liquid crystal light valves 40R to 40B and the pixels of the reflective liquid crystal light valve 50 can be made to correspond one-to-one. Further, since the relay lens 16 is composed of a large number of lenses, aberration correction is good, and the luminance distribution formed by each of the transmissive liquid crystal light valves 40R to 40B is accurately transmitted to the reflective liquid crystal light valve 50. Can do.

  On the other hand, the projection display device 100 includes a display control device 200 (not shown) that controls the transmissive liquid crystal light valves 40R to 40B and the reflective liquid crystal light valve 50. Hereinafter, the transmissive liquid crystal light valves 40R to 40B are generically referred to as color modulation light valves, and the reflective liquid crystal light valve 50 is generically referred to as a luminance modulation light valve. In the present embodiment, the color modulation light valve determines the display resolution (refers to the resolution perceived by the observer when the observer views the display image of the projection display device 100).

Next, the configuration of the display control apparatus 200 will be described in detail with reference to FIGS.
FIG. 4 is a block diagram illustrating a hardware configuration of the display control apparatus 200.
As shown in FIG. 4, the display control device 200 reads out from the CPU 70 that controls the operation and the entire system based on the control program, the ROM 72 that stores the control program of the CPU 70 in a predetermined area, the ROM 72, and the like. It is composed of a RAM 74 for storing data and calculation results required in the calculation process of the CPU 70, and an I / F 78 that mediates input / output of data to / from an external device, and these are used for transferring data. They are connected to each other via a bus 79 which is a signal line so as to be able to exchange data.

The I / F 78 is connected as an external device to a light valve driving device 80 that drives the luminance modulation light valve and the color modulation light valve, a storage device 82 that stores data, tables, and the like as files, and an external network 199. And a signal line for connecting.
The storage device 82 stores HDR display data.
The HDR display data is image data capable of realizing a high luminance dynamic range that cannot be realized by a conventional image format such as sRGB, and stores pixel values indicating pixel luminance levels for all pixels of the image. Currently, it is used to synthesize CG objects into actual scenery, especially in the CG world. Although there are various image formats, there are many formats in which pixel values are stored in a floating-point format in order to realize a luminance dynamic range higher than a conventional image format such as sRGB. As values to be stored, physical radiance that does not consider human visual characteristics (Radiance = W / (sr · m ² )), or luminance that considers human visual characteristics (luminance = cd / m ² ). It is also a feature that it is a value regarding. In this embodiment, a format in which pixel values indicating radiance levels for each of the three primary colors of RGB are stored as floating point values for one pixel as HDR display data is used. For example, a value of (1.2, 5.4, 2.3) is stored as the pixel value of one pixel.

  The HDR display data is generated based on a HDR image having a high luminance dynamic range and a captured HDR image. However, with current film cameras and digital still cameras, HDR images with a high luminance dynamic range in nature cannot be taken at a time. Therefore, one HDR image is generated from a plurality of photographed images whose exposure is changed by some method. For details of the method for generating HDR display data, see, for example, publicly known document 1 “PEDebevec, J. Malik,“ Recovering High Dynamic Range Radiance Maps from Photographs ”, Proceedings of ACM SIGGRAPH97, pp.367-378 (1997). It is published in.

Assuming that the luminance level of the pixel p in the HDR display data is Rp, the reflectance of the pixel corresponding to the pixel p of the luminance modulation light valve is T1, and the transmittance of the pixel corresponding to the pixel p of the color modulation light valve is T2, (1) and (2) hold.

Rp = Tp × Rs (1)
Tp = T1 × T2 × G (2)

However, in the above formulas (1) and (2), Rs is the luminance of the light source 10 and G is a gain, both of which are constants. Tp is a light modulation rate.

From the above equations (1) and (2), it can be seen that there are an infinite number of combinations of T1 and T2 for the pixel p. However, T1 and T2 may not be arbitrarily determined. Since the image quality may deteriorate depending on the method of determination, T1 and T2 need to be appropriately determined in consideration of the image quality.
When the luminance modulation light valve and the color modulation light valve have different resolutions, the pixel p1 is imaged across a plurality of pixels of the color modulation light valve for one pixel p1 of the luminance modulation light valve, and vice versa. For one pixel p2 of the color modulation light valve, a plurality of pixels of the luminance modulation light valve are imaged on the pixel p2. Here, when calculating the reflectance T1 for the pixel p1 of the luminance modulation light valve, if the transmittance T2 of a plurality of overlapping pixels of the color modulation light valve is determined, an average value of the transmittance T2 is calculated. Considering the calculated average value and the like as the transmittance T2 of the pixel corresponding to the pixel p1 of the color modulation light valve, it is conceivable to calculate the reflectance T1 by the above equations (1) and (2). However, since the average value or the like is regarded as the transmittance T2 of the color modulation light valve, an error is inevitably generated there. This error occurs regardless of the order of determination, regardless of whether the reflectance T1 of the luminance modulation light valve is determined first or the transmittance T2 of the color modulation light valve is determined first. The modulation light valve and the color modulation light valve that determine the display resolution have a large visual influence, so it is better to minimize the error.

  Therefore, let us examine how the magnitude of the error changes depending on the order of determination. First, consider determining the transmittance T2 of the color modulation light valve first. The reflectance T1 of the pixel p1 of the luminance modulation light valve is calculated by calculating the average value or the like of the transmittance T2 of a plurality of overlapping pixels of the color modulation light valve, and using the above formula (1 ) And (2). As a result, when viewed from the pixel p1 of the luminance modulation light valve, the reflectance T1 has an error with respect to the transmittance T2 of a plurality of overlapping pixels of the color modulation light valve, but the degree of error is an average value or the like. This is the degree of error caused by statistical calculations. On the other hand, when viewed from the pixel p2 of the color modulation light valve, even if the transmittance T2 is calculated as an average value or the like of the reflectance T1 of a plurality of overlapping pixels of the luminance modulation light valve, Thus, a large error may occur that does not satisfy the above equations (1) and (2). This is because even if the relationship (a relationship satisfying the above equations (1) and (2)) with a plurality of overlapping pixels of the color modulation light valve is defined based on the pixel p1, the opposite relationship is not necessarily established. It is thought to be caused. Therefore, the error of the transmittance T2 of the color modulation light valve is likely to be larger.

The same applies to the opposite case, and when the reflectance T1 of the luminance modulation light valve is determined first, there is a high possibility that the error of the reflectance T1 of the luminance modulation light valve will be larger.
From the above, from the viewpoint of improving the image quality, the reflectance or transmittance (hereinafter referred to as reflectance or the like) of the luminance modulation light valve and the color modulation light valve that determines the display resolution is determined later. It can be concluded that the effect of error is less. In this embodiment, since the color modulation light valve determines the display resolution, the transmittance T2 of the color modulation light valve is determined later.

Further, the storage device 82 stores a control value registration table 400 in which control values of the luminance modulation light valve are registered.
FIG. 5 is a diagram illustrating a data structure of the control value registration table 400.
In the control value registration table 400, as shown in FIG. 5, one record is registered for each control value of the luminance modulation light valve. Each record includes a field in which the control value of the luminance modulation light valve is registered and a field in which the reflectance of the luminance modulation light valve is registered.

  In the example of FIG. 5, “0” is registered as the control value and “0.003” as the reflectance is registered in the first row record. This indicates that when the control value “0” is output to the luminance modulation light valve, the reflectance of the luminance modulation light valve becomes 0.3%. Note that FIG. 5 shows an example in which the number of gradations of the luminance modulation light valve is 4 bits (0 to 15 values), but in reality, there is a record corresponding to the number of gradations of the luminance modulation light valve. be registered. For example, when the number of gradations is 8 bits, 256 records are registered.

The storage device 82 stores control value registration tables 420R, 420G, and 420B in which the control values of the color modulation light valves are registered for each color modulation light valve.
FIG. 6 is a diagram illustrating a data structure of the control value registration table 420R.
In the control value registration table 420R, as shown in FIG. 6, one record is registered for each control value of the transmissive liquid crystal light valve 40R. Each record includes a field in which the control value of the transmissive liquid crystal light valve 40R is registered and a field in which the transmittance of the transmissive liquid crystal light valve 40R is registered.

  In the example of FIG. 6, “0” is registered as the control value and “0.004” is registered as the transmittance in the first row record. This indicates that when the control value “0” is output to the transmissive liquid crystal light valve 40R, the transmittance of the transmissive liquid crystal light valve 40R is 0.4%. FIG. 6 shows an example in which the number of gradations of the color modulation light valve is 4 bits (0 to 15 values). However, in actuality, there is a record corresponding to the number of gradations of the color modulation light valve. be registered. For example, when the number of gradations is 8 bits, 256 records are registered.

The data structure of the control value registration tables 420G and 420B is not particularly shown, but has the same data structure as that of the control value registration table 420R. However, the difference from the control value registration table 420R is that the transmittance corresponding to the same control value is different.
Next, the configuration of the CPU 70 and the processing executed by the CPU 70 will be described.
The CPU 70 includes a microprocessing unit (MPU) or the like, starts a predetermined program stored in a predetermined area of the ROM 72, and executes display control processing shown in the flowchart of FIG. 7 according to the program. .

FIG. 7 is a flowchart showing the display control process.
The display control process is a process of determining the control values of the luminance modulation light valve and the color modulation light valve based on the HDR display data, and driving the luminance modulation light valve and the color modulation light valve based on the determined control value. When executed in the CPU 70, as shown in FIG. 7, first, the process proceeds to step S100.

In step S100, the HDR display data is read from the storage device 82.
In step S102, the read HDR display data is analyzed, and a histogram of pixel values, a maximum value, a minimum value, an average value, and the like of the luminance level are calculated. This analysis result is for use in automatic image correction such as brightening a dark scene, darkening a scene that is too bright, or coordinating intermediate contrast, or for tone mapping.

Next, the process proceeds to step S104, and tone mapping is performed on the luminance level of the HDR display data to the luminance dynamic range of the projection display device 100 based on the analysis result of step S102.
FIG. 8 is a diagram for explaining tone mapping processing.
As a result of analyzing the HDR display data, it is assumed that the minimum value of the luminance level included in the HDR display data is Smin and the maximum value is Smax. Further, it is assumed that the minimum value of the luminance dynamic range of the projection display apparatus 100 is Dmin and the maximum value is Dmax. In the example of FIG. 8, since Smin is smaller than Dmin and Smax is larger than Dmax, HDR display data cannot be appropriately displayed as it is. Therefore, normalization is performed so that the histogram of Smin to Smax falls within the range of Dmin to Dmax.

Details of tone mapping are disclosed in, for example, publicly known document 2 “F. Drago, K. Myszkowski, T. Annen, N. Chiba,“ Adaptive Logarithmic Mapping For Displaying High Contrast Scenes ”, Eurographics 2003, (2003)”. It is posted.
Next, the process proceeds to step S106, and the HDR image is resized (enlarged or reduced) in accordance with the resolution of the color modulation light valve. At this time, the HDR image is resized while maintaining the aspect ratio of the HDR image. Examples of the resizing method include an average value method, an intermediate value method, and a nearest neighbor method (nearest neighbor method).

Next, the process proceeds to step S108, and based on the luminance level Rp of each pixel of the resized image and the luminance Rs of the light source 10, the light modulation rate Tp is calculated for each pixel of the resized image by the above equation (1).
Next, the process proceeds to step S110, where an initial value (for example, 0.2) is given as the transmittance T2 of each pixel of the color modulation light valve, and the transmittance T2 of each pixel of the color modulation light valve is provisionally determined.

  Next, the process proceeds to step S112, and based on the calculated light modulation rate Tp, provisionally determined transmittance T2 and gain G, the reflection of the luminance modulation light valve in units of pixels of the color modulation light valve according to the above equation (2). The rate T1 ′ is calculated. Here, since the color modulation light valve is composed of three transmissive liquid crystal light valves 40R to 40B, the reflectance T1 'is calculated for each of the three primary colors of RGB for the same pixel. On the other hand, since the luminance modulation light valve is composed of one reflection type liquid crystal light valve 50, the average value thereof is calculated as T1 'of the pixel.

Next, the process proceeds to step S114, and for each pixel of the luminance modulation light valve, the weighted average value of the reflectance T1 ′ calculated for the pixel of the color modulation light valve overlapping with the pixel on the optical path is used as the reflectance T1 of the pixel. Calculate as Weighting is performed based on the area ratio of overlapping pixels.
Next, the process proceeds to step S116, and for each pixel of the luminance modulation light valve, a control value corresponding to the reflectance T1 calculated for that pixel is read from the control value registration table 400, and the read control value is controlled for that pixel. Determine as value. In reading the control value, the reflectance closest to the calculated reflectance T1 is searched from the control value registration table 400, and the control value corresponding to the reflectance found by the search is read. This search is performed using, for example, a binary search method, thereby realizing a high-speed search.

  Next, the process proceeds to step S118, and for each pixel of the color modulation light valve, the weighted average value of the reflectance T1 determined for the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is calculated, and the calculated average value Based on the light modulation rate Tp and the gain G calculated in step S108, the transmittance T2 of the pixel is calculated by the above equation (2). Weighting is performed based on the area ratio of overlapping pixels.

  Next, the process proceeds to step S120, and for each pixel of the color modulation light valve, a control value corresponding to the transmittance T2 calculated for the pixel is read from the control value registration tables 420R to 420B, and the read control value is read from the pixel. Is determined as the control value. In the reading of the control value, the transmittance that most closely approximates the calculated transmittance T2 is searched from the control value registration tables 420R to 420B, and the control value corresponding to the transmittance found by the search is read. This search is performed using, for example, a binary search method, thereby realizing a high-speed search.

Next, the process proceeds to step S122, the control values determined in steps S116 and S120 are output to the light valve driving device 80, the brightness modulation light valve and the color modulation light valve are driven to project a display image, and a series of operations are performed. End the process and return to the original process.
Next, the operation of the present embodiment will be described with reference to FIGS.
In the following, all of the color modulation light valves have a resolution of 18 horizontal pixels × 12 vertical pixels and a gradation number of 4 bits, and the luminance modulation light valves have a resolution of 15 horizontal pixels × 10 vertical pixels and a 4-bit resolution. The case where the number of gradations is provided will be described as an example. The diagrams of the luminance modulation light valve and the color modulation light valve are both viewed from the light source 10 side.

  In the display control device 200, the HDR display data is read through steps S100 to S104, the read HDR display data is analyzed, and the luminance level of the HDR display data is determined based on the analysis result. Tone-mapped to 100 luminance dynamic range. Next, through step S106, the HDR image is resized in accordance with the resolution of the color modulation light valve.

  Next, through step S108, the light modulation rate Tp is calculated for each pixel of the resized image. For example, the light modulation rate Tp of the pixel p in the resized image is such that the luminance level Rp (R, G, B) of the pixel p is (1.2, 5.4, 2.3) and the luminance Rs (R, R, If (G, B) is (10000, 10000, 10000), then (1.2, 5.4, 2.3) / (10000, 10000, 10000) = (0.00012, 0.00054, 0.00023).

FIG. 9 is a diagram showing a case where the transmittance T2 of the color modulation light valve is provisionally determined.
Next, through step S110, the transmittance T2 of each pixel of the color modulation light valve is provisionally determined. When the pixels in the upper left four sections of the color modulation light valve are p21 (upper left), p22 (upper right), p23 (lower left), and p24 (lower right), the transmittance T2 of the pixels p21 to p24 is shown in FIG. Thus, an initial value T20 is given.

FIG. 10 is a diagram illustrating a case where the reflectance T1 ′ of the luminance modulation light valve is calculated for each pixel of the color modulation light valve.
Next, through step S112, the reflectance T1 ′ of the luminance modulation light valve is calculated for each pixel of the color modulation light valve. When attention is paid to the pixels p21 to p24, the reflectances T11 to T14 of the luminance modulation light valves corresponding to the pixels p21 to p24 are as shown in FIG. It can be calculated by the following formulas (3) to (6).

Actually calculate using numerical values. When Tp1 = 0.00012, Tp2 = 0.05, Tp3 = 0.02, Tp4 = 0.01, T20 = 0.1, T11 = 0.0012, T12 = 0.5, T13 = 0.2, T14 = 0.1 according to the following equations (3) to (6). Become.

T11 = Tp1 / T20 (3)
T12 = Tp2 / T20 (4)
T13 = Tp3 / T20 (5)
T14 = Tp4 / T20 (6)

FIG. 11 is a diagram illustrating a case where the reflectance T1 of each pixel of the luminance modulation light valve is determined.

  Next, through step S114, the reflectance T1 of each pixel of the luminance modulation light valve is determined. Since the color modulation light valve and the luminance modulation light valve are in an inverted image relationship by the relay lens 16, the pixels in the upper left four sections of the color modulation panel are imaged on the lower right portion of the luminance modulation light valve. When the pixels in the lower right four sections of the luminance modulation light valve are p11 (lower right), p12 (lower left), p13 (upper right), and p14 (upper left), as shown in FIG. Since the color modulation light valve and the luminance modulation light valve have different resolutions, they overlap with the pixels p21 to p24 on the optical path. Since the resolution of the color modulation light valve is 18 × 12 and the resolution of the luminance modulation light valve is 15 × 10, the pixel p11 can be divided into a 6 × 6 rectangular area from the least common multiple. Then, the overlapping area ratio of the pixel p11 and the pixels p21 to p24 is 25: 5: 5: 1 as shown in FIG. Therefore, the reflectance T15 of the pixel p11 can be calculated by the following equation (7) as shown in FIG.

Actually calculate using numerical values. When T11 = 0.0012, T12 = 0.5, T13 = 0.2, and T14 = 0.002, T15 = 0.008 according to the following equation (7).

T15 = (T11 × 25 + T12 × 5 + T13 × 5 + T14 × 1) / 36 (7)

Similarly to the pixel p11, the reflectances T16 to T18 of the pixels p12 to p14 can be obtained by calculating a weighted average value based on the area ratio.

  Next, through step S116, for each pixel of the luminance modulation light valve, a control value corresponding to the reflectance T1 calculated for that pixel is read from the control value registration table 400, and the read control value is It is determined as a pixel control value. For example, since T15 = 0.008, referring to the control value registration table 400, 0.09 is the closest value as shown in FIG. Therefore, “8” is read from the control value registration table 400 as the control value of the pixel p11.

FIG. 12 is a diagram illustrating a case where the transmittance T2 of each pixel of the color modulation light valve is determined.
Next, through step S118, the transmittance T2 of each pixel of the color modulation light valve is determined. As shown in FIG. 12A, the pixel p24 overlaps the pixels p11 to p14 on the optical path because the color modulation light valve and the luminance modulation light valve have different resolutions. Since the resolution of the color modulation light valve is 18 × 12 and the resolution of the luminance modulation light valve is 15 × 10, the pixel p24 can be divided into a rectangular area of 5 × 5 from its least common multiple. Then, the overlapping area ratio of the pixel p24 and the pixels p11 to p14 is 1: 4: 4: 16 as shown in FIG. Therefore, when attention is paid to the pixel p24, the reflectance T19 of the luminance modulation light valve corresponding to the pixel p24 can be calculated by the following equation (8). Then, the transmittance T24 of the pixel p24 can be calculated by the following equation (9) as shown in FIG. 12C when the gain G is “1”.

Actually calculate using numerical values. When T15 = 0.09, T16 = 0.33, T17 = 0.15, T18 = 0.06, and Tp4 = 0.01, T19 = 0.1188 and T24 = 0.0842 are obtained from the following equations (8) and (9).

T19 = (T15 × 1 + T16 × 4 + T17 × 4 + T18 × 16) / 25 (8)
T24 = Tp4 / T19 (9)

Similarly to the pixel p24, the transmittances T21 to T23 of the pixels p21 to p23 can be obtained by calculating a weighted average value based on the area ratio.

  Next, through step S120, for each pixel of the color modulation light valve, a control value corresponding to the transmittance T2 calculated for the pixel is read from the control value registration tables 420R to 420B, and the read control value is read out. Is determined as the control value of the pixel. For example, when T24 = 0.0842 for the pixel p24 of the transmissive liquid crystal light valve 40R, referring to the control value registration table 420R, 0.07 is the closest approximation as shown in FIG. Therefore, “7” is read from the control value registration table 420R as the control value of the pixel p24.

Then, through step S122, the determined control value is output to the light valve driving device 80. Thereby, the luminance modulation light valve and the color modulation light valve are driven, and an optical image is formed on the pixel surface of the luminance modulation light valve and the color modulation light valve.
In the projection display device 100, the light from the luminance distribution uniformizing unit 12 is separated into light of RGB three primary colors by the dichroic mirrors 44a and 44b, and the transmittance is controlled for each pixel by each color modulation light valve. Each separated light is first-order modulated. Next, the light from each color modulation light valve is combined by the dichroic prism 48, and the combined light is incident on the luminance modulation light valve. At this time, an optical image of each color modulation light valve is formed on the pixel surface of the luminance modulation light valve via the relay lens 16. The light from the dichroic prism 48 is reflected by the luminance modulation light valve, and the reflectance is controlled for each pixel, whereby the light from the dichroic prism 48 is secondarily modulated.

  In this way, in the present embodiment, the light source 10, the dichroic mirrors 44a and 44b that separate the light from the light source 10 into RGB three primary colors, and the light separated by the dichroic mirrors 44a and 44b are incident and transmitted, respectively. A plurality of color modulation light valves having a plurality of pixels capable of independently controlling the rate T2, a dichroic prism 48 for synthesizing light from each color modulation light valve, and an optical image of each color modulation light valve for a reflective liquid crystal light valve 50 A relay lens 16 that forms an image on the pixel surface, and a reflective liquid crystal light valve 50 that has a plurality of pixels that receive light from the relay lens 16 and that can independently control the reflectance T1.

Thereby, since the light from the light source 10 is modulated through the color modulation light valve and the luminance modulation light valve, a relatively high luminance dynamic range and number of gradations can be realized.
Further, since the luminance modulation light valve is constituted by the reflective liquid crystal light valve 50 having a high aperture ratio, the luminance of the display image is secured to some extent even if the alignment accuracy between the color modulation light valve and the luminance modulation light valve is not high. be able to. In addition, polarization characteristics can be maintained in light transmission between the color modulation light valve and the luminance modulation light valve. Therefore, it is possible to suppress a decrease in the brightness of the display image as compared with the conventional case.

Furthermore, since the optical image of each color modulation light valve is formed on the pixel surface of the luminance modulation light valve via the relay lens 16, the optical image of each color modulation light valve is connected to the pixel surface of the luminance modulation light valve with relatively high accuracy. Since an image can be obtained, relatively high-precision modulation can be performed. Therefore, it is possible to reduce the possibility that the image quality is deteriorated as compared with the conventional case.
Furthermore, since it is not necessary to use a solid-state laser or a semiconductor laser as the light source 10, it is possible to reduce the size and increase the brightness of the apparatus as compared with the conventional case.

Further, in the present embodiment, the color modulation light valve and the luminance modulation light valve are liquid crystal light valves.
Thereby, since an existing optical component can be used, an increase in cost can be further suppressed.
Furthermore, in the present embodiment, the luminance distribution uniformizing unit 12 that uniformizes the luminance distribution of the light from the light source 10 is provided on the optical path between the light source 10 and the color modulation unit 14.

This can reduce the possibility of uneven brightness.
Furthermore, in the present embodiment, the luminance distribution uniformizing unit 12 includes a polarization conversion element 12c that polarizes the light from the light source 10 in the incident polarization direction of the color modulation light valve.
As a result, most of the amount of light from the light source 10 is to be modulated by the color modulation light valve, so that the brightness of the display image can be improved.

  Furthermore, in this embodiment, the transmittance T2 of each pixel of the color modulation light valve is provisionally determined, and the reflectance T1 of each pixel of the luminance modulation light valve is determined based on the provisionally determined transmittance T2 and HDR display data. The control value of each pixel of the luminance modulation light valve is determined based on the determined reflectance T1, and the transmittance T2 of each pixel of the color modulation light valve is determined based on the determined reflectance T1 and HDR display data. The control value for each pixel of the color modulation light valve is determined based on the determined transmittance T2.

Thereby, since the transmittance T2 of the color modulation light valve that determines the display resolution is determined later, the influence of the error can be suppressed, and the possibility that the image quality is deteriorated can be reduced. Furthermore, since it is not necessary to maintain the number of gradation tables corresponding to the number of gradations, even if the number of gradations is increased, the size and generation time of the gradation table do not increase so much.
Furthermore, in the present embodiment, the reflectance T1 ′ of the luminance modulation light valve is calculated for each pixel of the color modulation light valve based on the provisionally determined transmittance T2 and HDR display data, and the calculated reflectance T1 ′ is calculated. Based on this, the reflectance T1 of each pixel of the luminance modulation light valve is calculated.

  When the luminance modulation light valve and the color modulation light valve have different resolutions, rather than directly calculating the reflectance T1 of each pixel of the luminance modulation light valve based on the provisionally determined transmittance T2, it is temporarily determined. It is easier to calculate the reflectance T1 ′ of each luminance modulation light valve after calculating the reflectance T1 ′ of the luminance modulation light valve in units of pixels of the color modulation light valve based on the transmitted transmittance T2. become. Therefore, when the luminance modulation light valve and the color modulation light valve have different resolutions, the reflectance T1 of each pixel of the luminance modulation light valve can be calculated relatively easily.

Further, in the present embodiment, for each pixel of the luminance modulation light valve, the reflectance T1 of the pixel is calculated based on the reflectance T1 ′ calculated for the pixel of the color modulation light valve that overlaps the pixel on the optical path. It is supposed to be.
Thus, when the luminance modulation light valve and the color modulation light valve have different resolutions, the reflectance T1 of each pixel of the luminance modulation light valve is the transmittance of the pixel of the color modulation light valve that overlaps the pixel in the optical path. Since it is a relatively appropriate value for T2, the possibility of image quality deterioration can be further reduced. In addition, the reflectance T1 of each pixel of the luminance modulation light valve can be calculated more easily.

Further, in the present embodiment, for each pixel of the luminance modulation light valve, the weighted average value of the reflectance T1 ′ calculated for the pixel of the color modulation light valve that overlaps the pixel on the optical path is used as the reflectance T1 of the pixel. Is calculated as
Thus, when the luminance modulation light valve and the color modulation light valve have different resolutions, the reflectance T1 of each pixel of the luminance modulation light valve is the transmittance of the pixel of the color modulation light valve that overlaps the pixel in the optical path. Since it becomes a more appropriate value with respect to T2, the possibility that the image quality deteriorates can be further reduced. In addition, the reflectance T1 of each pixel of the luminance modulation light valve can be calculated more easily.

Further, in the present embodiment, for each pixel of the color modulation light valve, the transmittance T2 of the pixel is calculated based on the reflectance T1 determined for the pixel of the luminance modulation light valve that overlaps the pixel on the optical path. It is like that.
Accordingly, when the luminance modulation light valve and the color modulation light valve have different resolutions, the transmittance T2 of each pixel of the color modulation light valve is the reflectance of the pixel of the luminance modulation light valve that overlaps the pixel in the optical path. Since it is a relatively appropriate value for T1, the possibility of image quality degradation can be further reduced. Further, the transmittance T2 of each pixel of the color modulation light valve can be calculated relatively easily.

Furthermore, in the present embodiment, for each pixel of the color modulation light valve, a weighted average value of the reflectance T1 determined for the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is calculated, and based on the average value Then, the transmittance T2 of the pixel is calculated.
Accordingly, when the luminance modulation light valve and the color modulation light valve have different resolutions, the transmittance T2 of each pixel of the color modulation light valve is the reflectance of the pixel of the luminance modulation light valve that overlaps the pixel in the optical path. Since it becomes a more appropriate value with respect to T1, the possibility that the image quality is deteriorated can be further reduced. In addition, the transmittance T2 of each pixel of the color modulation light valve can be calculated more easily.

Furthermore, in this embodiment, a color modulation light valve is used as the first-stage light modulation element, and a luminance modulation light valve is used as the second-stage light modulation element.
Accordingly, since only one light modulation element needs to be added to the conventional projection display device, the projection display device 100 can be configured relatively easily.
In the first embodiment, the color modulation light valve corresponds to the first light modulation element of the invention 1, 2, 10 or 11, and the reflective liquid crystal light valve 50 is the invention 1 to 3, 10 to 12. This corresponds to the second light modulation element, the reflection type light modulation element of the invention 1, 2, 10 or 11, or the reflection type liquid crystal display element of the invention 3 or 12. The dichroic mirrors 44a and 44b correspond to the light separating means of the invention 2 or 11, and the dichroic prism 48 corresponds to the light combining means of the invention 2 or 11.

Next, a second embodiment of the present invention will be described with reference to the drawings. 13 and 14 are diagrams showing a second embodiment of the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention.
In the present embodiment, the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention are applied to a direct-view display device 110 as shown in FIG. Hereinafter, only the parts different from the first embodiment will be described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

First, the configuration of the direct-view display device 110 will be described with reference to FIG.
FIG. 13 is a block diagram illustrating a hardware configuration of the direct-view display device 110.
As shown in FIG. 13, the direct-view display device 110 includes a light source 10, a luminance distribution uniformizing unit 12 that uniformizes the luminance distribution of light incident from the light source 10, and a light incident from the luminance distribution uniforming unit 12. The luminance modulation unit 18 that modulates the luminance of the entire wavelength region, the projection unit 20 that projects the light incident from the luminance modulation unit 18, and the luminance of the RGB three primary colors in the wavelength region of the light incident from the projection unit 20 are respectively modulated. A reflective color liquid crystal panel 66 is used.

  The luminance modulation unit 18 includes a transmissive liquid crystal light valve 62 in which a plurality of pixels whose transmittance can be independently controlled are arranged in a matrix, and a field lens 64. Then, the light from the luminance distribution uniformizing unit 12 enters through the field lens 64, the luminance in the entire wavelength region of the incident light is modulated by the transmissive liquid crystal light valve 62, and the modulated light is emitted to the projection unit 20. To do.

  The transmissive liquid crystal light valve 62 includes a pixel electrode and a glass substrate on which switching elements such as thin film transistors and thin film diodes for driving the pixel electrode are formed in a matrix and a glass substrate on which a common electrode is formed over the entire surface. This is an active matrix type liquid crystal display element in which a TN liquid crystal is sandwiched between and a polarizing plate is disposed on the outer surface. The transmissive liquid crystal light valve 62 is driven in a normally white mode in which a white / bright (transmission) state is applied when no voltage is applied, and a black / dark (non-transmission) state is applied when a voltage is applied, or vice versa. The gradation between light and dark is analog controlled according to the given control value.

Next, the configuration of the reflective color liquid crystal panel 66 will be described in detail with reference to FIG.
FIG. 14 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction.
As shown in FIG. 14, the reflective color liquid crystal panel 66 includes a polarizing plate 501, a phase difference plate 502, a front glass substrate 503, a color filter 504, a common electrode 505, a liquid crystal 506, a reflective pixel electrode 507, a thin film transistor 508, and a rear glass. A substrate 509 is used. The front glass substrate 503 and the rear glass substrate 509 are arranged to face each other at a predetermined interval, and a liquid crystal layer filled with the liquid crystal 506 is formed therebetween. A color filter 504 and a common electrode 505 are stacked in that order on the surface of the front glass substrate 503 on the liquid crystal layer side. A reflective pixel electrode 507, a thin film transistor 508, and signal wiring (not shown) are provided in a matrix on the surface of the rear glass substrate 509 on the liquid crystal layer side. Further, on the surface of the front glass substrate 503 opposite to the liquid crystal layer, a phase difference plate 502 and a polarizing plate 501 are arranged close to each other in that order.

  The reflective pixel electrode 507 is made of a highly reflective metal material such as aluminum, and is formed so as to cover the thin film transistor 508 and the signal wiring through an insulating film (not shown). Therefore, the aperture ratio becomes high. Further, by forming a fine uneven portion on the insulating film by using photolithography and forming the reflective pixel electrode 507 on the insulating film, the reflective pixel electrode 507 having the fine uneven portion on the surface can be formed. Since the reflective pixel electrode 507 can scatter and reflect the incident light by the concavo-convex portion, the viewing angle of the reflective color liquid crystal panel 66 can be expanded.

  The light beam incident on the reflective color liquid crystal panel 66 reaches the reflective pixel electrode 507 through the liquid crystal layer, is reflected there, and reaches the polarizing plate 501 again through the liquid crystal layer. When the reflective color liquid crystal panel 66 is driven, the arrangement of the liquid crystal molecules changes according to the control signal, and the polarization state of the incident light beam changes accordingly, so that the amount of light transmitted through the polarizing plate 501 again depends on the control signal. Change. In this way, the reflectance T1 is controlled for each pixel.

  A feature of this embodiment is that a reflective color liquid crystal panel 66 is used as a light modulation element in the subsequent stage. In the direct-view display device 110, an optical image of the transmissive liquid crystal light valve 62 is formed on the display surface of the reflective color liquid crystal panel 66 by the projection unit 20. Here, when a transmissive liquid crystal display panel is used instead of the reflective color liquid crystal panel 66, the opening is narrow, so that light does not pass through the opening due to a slight alignment error, and the brightness of the display image is lowered. Further, since the light shielding part is conspicuous, moire is easily noticeable. On the other hand, when the reflective color liquid crystal panel 66 is used as in the present embodiment, since the opening is large, the luminance of the display image does not decrease so much even if there is a slight alignment error. Furthermore, since the light shielding portion is narrow, moire is not noticeable.

  The display control device 200 controls the transmissive liquid crystal light valve 62 and the reflective color liquid crystal panel 66. This control can be performed in the same manner as in the first embodiment. That is, the control for the transmissive liquid crystal light valve 62 is performed similarly to the control for the transmissive liquid crystal light valves 40R to 40B, and the control for the reflective color liquid crystal panel 66 is performed similarly to the control for the reflective liquid crystal light valve 50. Good.

Next, the operation of the present embodiment will be described.
In the direct-view display device 110, the light from the luminance distribution uniformizing unit 12 is primarily modulated by controlling the transmittance T <b> 2 for each pixel by the transmissive liquid crystal light valve 62, and is transmitted by the projection unit 20. An optical image of the liquid crystal light valve 62 is formed on the display surface of the reflective color liquid crystal panel 66. The light from the transmissive liquid crystal light valve 62 is reflected by the reflective color liquid crystal panel 66, and the light from the transmissive liquid crystal light valve 62 is secondarily modulated by controlling the reflectance T1 for each pixel. The At this time, since the uneven portion is formed in the reflective pixel electrode 507 of the reflective color liquid crystal panel 66, the light from the transmissive liquid crystal light valve 62 is scattered and reflected by the uneven portion, and an image is displayed.

  In this way, in the present embodiment, the light source 10, the transmissive liquid crystal light valve 62 having a plurality of pixels that can receive light from the light source 10 and can independently control the transmittance T2, and the reflectance T1. A reflective color liquid crystal panel 66 having a plurality of independently controllable pixels and a projection unit 20 that forms an optical image of the transmissive liquid crystal light valve 62 on the display surface of the reflective color liquid crystal panel 66 are provided.

Thereby, since the light from the light source 10 is modulated via the transmissive liquid crystal light valve 62 and the reflective color liquid crystal panel 66, a relatively high luminance dynamic range and number of gradations can be realized.
Further, since the light modulation element at the rear stage is constituted by the reflective color liquid crystal panel 66 having a high aperture ratio, even if the alignment accuracy between the transmissive liquid crystal light valve 62 and the reflective color liquid crystal panel 66 is not high, the display image is displayed. A certain level of luminance can be secured. In addition, polarization characteristics can be maintained in light transmission between the transmissive liquid crystal light valve 62 and the reflective color liquid crystal panel 66. Therefore, it is possible to suppress a decrease in the brightness of the display image as compared with the conventional case.

Furthermore, since it is not necessary to use a solid-state laser or a semiconductor laser as the light source 10, it is possible to reduce the size and increase the brightness of the apparatus as compared with the conventional case.
Further, in the present embodiment, the concavo-convex portion is formed on the reflective pixel electrode 507 of the reflective color liquid crystal panel 66.
Thereby, it can suppress that the viewing angle of the reflection type color liquid crystal panel 66 falls.

In the second embodiment, the reflective color liquid crystal panel 66 corresponds to the second light modulation element of the invention 5 or 14, or the reflection light modulation display panel of the invention 5, 7, 14 or 16.
Next, a third embodiment of the present invention will be described with reference to the drawings. FIGS. 15 to 17 are diagrams showing a third embodiment of the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention.

  In the present embodiment, the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention are applied to a direct-view display device 110 as shown in FIG. The difference from this embodiment is that the reflective color liquid crystal panel 66 has a light diffusion structure for diffusing light toward the viewer. Hereinafter, only the parts different from the second embodiment will be described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  Although the reflective color liquid crystal panel 66 has a characteristic of scattering and reflecting light in order to widen the viewing angle characteristic, for the purpose of improving the apparent brightness of the display image, the scattering angle range is not expanded unnecessarily but is a certain range. It is preferable to limit to. However, if such scattering reflection characteristics are uniformly formed over the entire surface of the reflective color liquid crystal panel 66, when the reflective color liquid crystal panel 66 is enlarged, the luminance distribution of the display image is uneven. Problems arise. This phenomenon will be described with reference to FIGS.

FIGS. 15 and 16 are diagrams for explaining an image observation state of the direct-view display device 110 having the large reflective color liquid crystal panel 66. FIG.
In FIG. 15, the scattering reflection angle range of the reflective color liquid crystal panel 66 is limited to a certain range, and the scattering reflection characteristics are uniform within the display surface. The light reaches the viewer, but only weak reflected light reaches the viewer as it moves away from the center. For this reason, the display image that can be seen by the viewer has a luminance distribution unevenness in which the central part is bright and the peripheral part is dark. In order to solve such a problem, as shown in FIG. 16, the scattered reflection characteristics are given directivity, and strong reflected light from any part of the display surface of the reflective color liquid crystal panel 66 is received by the viewer. Should be reached.

Specifically, the reflective color liquid crystal panel 66 is configured as follows.
FIG. 17 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction.
As shown in FIG. 17, an uneven portion 510 is formed on the reflective surface of the reflective pixel electrode 507. Here, the cross-sectional shape of the concave portion or the convex portion in the concavo-convex portion 510 is an asymmetric saw shape as viewed from the apex thereof. Further, the inclination of the concavo-convex portion 510 of each pixel varies depending on the distance from the center of the reflective color liquid crystal panel 66. That is, a reflection angle is formed so that strong reflected light reaches the viewer from any part of the display surface of the reflective color liquid crystal panel 66.

Next, the operation of the present embodiment will be described.
In the direct-view display device 110, the light from the luminance distribution uniformizing unit 12 is primarily modulated by controlling the transmittance T <b> 2 for each pixel by the transmissive liquid crystal light valve 62, and is transmitted by the projection unit 20. An optical image of the liquid crystal light valve 62 is formed on the display surface of the reflective color liquid crystal panel 66. The light from the transmissive liquid crystal light valve 62 is reflected by the reflective color liquid crystal panel 66, and the light from the transmissive liquid crystal light valve 62 is secondarily modulated by controlling the reflectance T1 for each pixel. The At this time, since the uneven portion 510 is formed on the reflective pixel electrode 507 of the reflective color liquid crystal panel 66, the light from the transmissive liquid crystal light valve 62 is scattered and reflected by each uneven portion 510 and an image is displayed. A high luminance distribution is formed around the direction of the viewer due to the difference in inclination of each uneven portion 510.

Thus, in this embodiment, a plurality of uneven portions 510 are formed in the reflective pixel electrode 507 of the reflective color liquid crystal panel 66, and the cross-sectional shape of the concave portion or the convex portion in each uneven portion 510 is asymmetrical when viewed from the apex. In addition, the degree of asymmetry was changed according to the distance from the center of the reflective color liquid crystal panel 66.
As a result, if the reflective color liquid crystal panel 66 is viewed from within a certain range, a viewing angle with almost no problem in viewing can be obtained, and the appearance brightness and uniformity of display brightness distribution of the display image are prevented from being lowered. can do.

In the third embodiment, the reflective color liquid crystal panel 66 corresponds to the reflective light modulation display panel of the invention 6, 8, 15 or 17.
In the first embodiment, the polarization beam splitter 52 is disposed between the relay lens 16 and the reflective liquid crystal light valve 50 to separate the incident light beam and the reflected light beam. A configuration not using the polarization beam splitter 52 is also possible.

FIG. 18 is a diagram illustrating a case where the projection display apparatus 100 is configured without using the polarization beam splitter 52.
As shown in FIG. 18, the projection display device 100 includes a light source 10, a luminance distribution uniformizing unit 12, a color modulation unit 14, a relay lens 16, a luminance modulation unit 18, and a projection unit 20.
The luminance modulator 18 includes a reflective liquid crystal light valve 50 in which a plurality of pixels whose reflectance can be controlled independently is arranged in a matrix, and a λ / 4 plate 54 for improving the contrast characteristics of the reflective liquid crystal light valve 50. And a polarizing plate 60. The λ / 4 plate 54 and the reflective liquid crystal light valve 50 are disposed off-axis with respect to the optical axes of the relay lens 16 and the projection unit 20. First, the light beam from the relay lens 16 is incident on the reflective liquid crystal light valve 50 through the λ / 4 plate 54, and the polarization state of the entire wavelength region of the incident light is modulated and reflected by the reflective liquid crystal light valve 50. . At this time, since the reflective liquid crystal light valve 50 is arranged obliquely with respect to the incident light beam, the reflected light beam is spatially separated from the incident light beam. Then, the reflected light is incident on the polarizing plate 60 through the λ / 4 plate 54, and a polarization component (luminance modulated light subjected to the second light modulation) necessary for image display is emitted to the projection unit 20.

Accordingly, since it is not necessary to provide the polarizing beam splitter 52, the loss of the amount of light is reduced, and the contrast reduction caused by the birefringence of the glass material constituting the polarizing beam splitter 52 can be prevented.
In the first embodiment, the luminance modulation light valve is configured by the reflective liquid crystal light valve 50. Instead, the luminance modulation light valve is configured by DMD 56 as shown in FIG. You can also.

FIG. 19 is a diagram illustrating a case where the projection display apparatus 100 is configured using the DMD 56.
As shown in FIG. 19, the projection display device 100 includes a light source 10, a luminance distribution uniformizing unit 12, a color modulation unit 14, a relay lens 16, a luminance modulation unit 18, and a projection unit 20.
The luminance modulation unit 18 includes a DMD 56 in which a plurality of pixels whose reflectance can be controlled independently is arranged in a matrix, and a TIR prism 58. The DMD 56 is disposed in front of the projection unit 20, and the dichroic prism 48 and the relay lens 16 are inclined (off-axis) with respect to the DMD 56 so that light enters at a predetermined incident angle via the TIR prism 58. Has been placed.

  The DMD 56 is a reflection type light modulation element that controls the reflection direction of the light beam as a mirror. In other words, the DMD 56 performs modulation by time control that switches a light passing state or a blocking state. When each pixel of the DMD 56 is controlled in a predetermined frame unit, for example, if the control is performed so that incident light is reflected toward the projection unit 20 for a half time of one frame, the luminance of the pixel becomes 1/2.

  First, light from the relay lens 16 is reflected by the TIR prism 58 and incident on the DMD 56, and the luminance in the entire wavelength region of the incident light is modulated by the DMD 56 and reflected. Then, a predetermined component of the reflected light beam is emitted to the projection unit 20 via the TIR prism 58. A TIR prism 58 is disposed between the relay lens 16 and the DMD 56. The TIR prism 58 is used to improve the contrast characteristics of an optical system using the DMD 56, and is a color modulation light valve. The imaging relationship of the DMD 56 is not affected.

Thereby, since the luminance modulation light valve is configured by the DMD 56 having a high aperture ratio, the luminance of the display image can be ensured to some extent even if the alignment accuracy between the color modulation light valve and the luminance modulation light valve is not high. In addition, the luminance modulation light valve can be digitally driven.
In the first embodiment, the P-polarized light is emitted from the dichroic prism 48. However, the present invention is not limited to this. When the S-polarized light is emitted from the dichroic prism 48, the dichroic prism 48 and the polarization beam splitter If a λ / 2 plate is provided on the optical path 52 and the polarization direction of the light beam is rotated by 90 °, the same optical arrangement as in FIG. 1 can be adopted. Further, in order to make the light in the S polarization direction enter the reflective liquid crystal light valve 50 as it is, the reflective liquid crystal light valve 50 and the λ / 4 plate 54 are projected below the polarizing beam splitter 52 (with the polarizing beam splitter 52 sandwiched therebetween). What is necessary is just to arrange | position on the other side of the part 20.

  In the first embodiment, the transmissive liquid crystal light valves 40R to 40B are configured using active matrix liquid crystal display elements. However, the present invention is not limited to this, and the transmissive liquid crystal light valves 40R to 40B are passive. A matrix type liquid crystal display element and a segment type liquid crystal display element can also be used. The active matrix type liquid crystal display has an advantage that precise gradation display can be performed, and the passive matrix type liquid crystal display element and the segment type liquid crystal display element have an advantage that they can be manufactured at low cost.

  In the first embodiment, since the luminance modulation light valve is composed of one reflective liquid crystal light valve 50, one control value registration table 400 is prepared, and the control value registration table 400 is prepared. However, the present invention is not limited to this, and control value registration tables 400R, 400G, and 400B are prepared for each of the RGB three primary colors. The control value of each pixel of the luminance modulation light valve can be determined based on 400B. Since the luminance modulation light valve modulates the luminance in the entire wavelength region of light, the control value registration table 400 registers the reflectance of light having typical wavelengths. However, the respective reflectances of the RGB three primary colors are not necessarily registered reflectances.

  Therefore, for the luminance modulation light valve, strictly, the reflectance corresponding to the control value is measured for each of the three primary colors of RGB, and the control value registration tables 400R to 400B are configured. Next, the reflectance T1 of each pixel of the luminance modulation light valve is determined for each of the RGB three primary colors, the reflectance closest to the reflectance T1 calculated for R is retrieved from the control value registration table 400R, and the search is performed by searching. A control value corresponding to the reflected reflectance is read out. Similarly, the corresponding control value is read out from the control value registration tables 400G and 400B based on the reflectance T1 calculated for G and the reflectance T1 calculated for B. Then, the average value of the control values read for the same pixel of the luminance modulation light valve is calculated as the control value of that pixel.

As a result, the control value of each pixel of the luminance modulation light valve becomes a relatively appropriate value with respect to the reflectance of each of the RGB primary colors of the pixel of the color modulation light valve that overlaps the pixel in the optical path. The possibility of doing so can be further reduced.
In the first embodiment, the color modulation light valve is configured as a light modulation element that determines display resolution. However, the present invention is not limited to this, and the luminance modulation light valve is a light modulation element that determines display resolution. It can also be configured as. In this case, after determining the transmittance T1 of each pixel of the color modulation light valve (the reflectance of the light modulation element determined in advance is T1), the reflectance T2 of each pixel of the luminance modulation light valve is determined. (The reflectance of the light modulation element, which will be determined later, is T2.) Is determined. Further, similarly to the above, the control value registration tables 400R to 400B are prepared for each of the three primary colors of RGB, and the control value of each pixel of the luminance modulation light valve is determined based on the control value registration tables 400R to 400B. You can also.

  Specifically, the reflectance T2 of each pixel of the luminance modulation light valve is determined for each of the RGB three primary colors, and the reflectance closest to the reflectance T2 calculated for R is searched from the control value registration table 400R. The control value corresponding to the reflectance retrieved by is read out. Similarly, the corresponding control value is read from the control value registration tables 400G and 400B based on the reflectance T2 calculated for G and the reflectance T2 calculated for B. Then, the average value of the control values read for the same pixel of the luminance modulation light valve is calculated as the control value of that pixel.

As a result, the control value of each pixel of the luminance modulation light valve becomes a relatively appropriate value with respect to the reflectance of each of the RGB primary colors of the pixel of the color modulation light valve that overlaps the pixel in the optical path. The possibility of doing so can be further reduced.
In the first embodiment, the control values of the luminance modulation light valve and the color modulation light valve are determined based on the HDR display data. However, normal 8-bit RGB image data for each color is used. In this case, a value of 0 to 255 in normal RGB image data is not a physical quantity of luminance but a relative value of 0 to 255. Therefore, in order to display the display device of the present invention based on normal RGB image data, the physical brightness Rp to be displayed or the reflectance Tp of the entire display device or the like must be determined from the normal RGB image. should not.

FIG. 20 is a diagram illustrating a data structure of the input value registration table 440.
Therefore, by using the input value registration table 440 of FIG. 20, it is possible to convert an input value of 0 to 255 of a normal RGB image into Tp such as physical reflectance, and the reflectance of this table. It is possible to easily change the display appearance (gradation characteristics) of a normal RGB image depending on the setting of equal Tp. Since the reflectance Tp in this table is Tp in the above equation (2), once this value is determined, a plurality of light modulations are performed by performing the same processing as in the first embodiment. The reflectance T1 and transmittance T2 of the element are determined and can be displayed.

FIG. 21 is a diagram showing the data structure of the input value registration table 460.
The input value registration table 460 in FIG. 21 uses the luminance Rp instead of the reflectance Tp. Since the luminance Rp in this table is Rp in the above equation (1), if this value is determined, the same processing as in the first embodiment is performed thereafter, so that the plurality of light modulation elements The reflectance T1 and the transmittance T2 are determined and can be displayed.

In the first embodiment, for each pixel of the color modulation light valve, the weighted average value of the reflectance T1 determined for the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is calculated. The transmittance T2 of the pixel is calculated based on the average value. However, the present invention is not limited to this. For each pixel of the color modulation light valve, the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is determined. Based on the control value, the reflectance T1 _table corresponding to the control value is read from the control value registration table 400, the weighted average value of the read reflectance T1 _table is calculated, and the pixel value is calculated based on the average value. It can also be configured to calculate the transmittance T2.

  In the first embodiment, the average value of the reflectance T1 ′ calculated for each of the three primary colors of RGB for the same pixel is calculated as T1 ′ of the pixel. However, the present invention is not limited to this. The reflectance T1 ′ may be calculated as it is for each of the three primary colors of RGB, and in step S114, the average value of the reflectance T1 calculated for each of the three primary colors of the same pixel may be calculated as T1 of that pixel.

  In the first embodiment, for each pixel of the color modulation light valve, the weighted average value of the reflectance T1 determined for the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is calculated. The transmittance T2 of the pixel is calculated based on the average value. However, the present invention is not limited to this. For each pixel of the color modulation light valve, the pixel of the luminance modulation light valve that overlaps the pixel on the optical path is determined. The maximum value, the minimum value, or the average value of the reflectance T1 can be calculated, and the transmittance T2 of the pixel can be calculated based on the calculated value.

  In the first embodiment, the color modulation light valve is composed of the transmissive liquid crystal light valves 40R to 40B. However, the present invention is not limited to this, and the light modulation having a plurality of pixels whose light propagation characteristics can be controlled independently. Any element can be used. Here, the light propagation characteristics refer to characteristics that affect light propagation, and include, for example, light transmission characteristics, reflection characteristics, refraction characteristics, and other propagation characteristics.

In the first embodiment, the light modulation element having a small number of pixels and the number of gradations is used for the sake of simplicity. However, the light modulation element having a large number of pixels and the number of gradations is used. Can be processed in the same manner as in the first embodiment.
In the first embodiment, for the sake of simplicity, the gain G is set to 1.0, but the gain G is not 1.0 depending on the hardware configuration. Further, when considering the actual calculation cost, it is better to register the control value, the reflectance and the like in the control value registration table in a manner including the influence of the gain G.

  In the second embodiment, the reflective pixel electrode 507 of the reflective color liquid crystal panel 66 is formed with a concavo-convex portion. However, the structure in which the reflective color liquid crystal panel 66 has diffusibility is provided. It is not limited to. For example, even when the surface of the reflective pixel electrode 507 is a smooth mirror surface, a transparent film having a scattering function is attached to the surface of the front glass substrate 503, or a structure using a scattering type liquid crystal as the liquid crystal 506 has the same diffusibility. You can have it. In the latter structure, the polarizing plate 501 and the retardation plate 502 are not necessary.

In the third embodiment, the uneven portion 510 is formed in the reflective pixel electrode 507 of the reflective color liquid crystal panel 66 for controlling the direction of the scattered reflected light, and the light scattered and reflected there is in a specific direction. However, the present invention is not limited to this, and a structure as shown in FIG. 22 can be employed.
FIG. 22 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction.

  On the surface opposite to the liquid crystal layer of the front glass substrate 503, a Fresnel lens 511 is provided as shown in FIG. The Fresnel lens 511 contains fine particles serving as a light scattering source in a dispersed manner, and at the same time, a stepped and concentric ring zone part 512 is formed on the surface thereof. Each annular zone 512 functions as a single large lens as a whole by functioning as a small refractive surface (prism surface). With this lens function, strong reflected light reaches the viewer from any part of the display surface of the reflective color liquid crystal panel 66.

As a result, if the reflective color liquid crystal panel 66 is viewed from within a certain range, a viewing angle with almost no problem in viewing can be obtained, and the appearance brightness and uniformity of display brightness distribution of the display image are prevented from being lowered. can do.
Further, in the first embodiment, the case where the control program stored in advance in the ROM 72 is executed when executing the processing shown in the flowchart of FIG. 7 is described, but the present invention is not limited to this. The program may be read into the RAM 74 from a storage medium storing the program indicating the above and executed.

  Here, the storage medium is a semiconductor storage medium such as RAM or ROM, a magnetic storage type storage medium such as FD or HD, an optical reading type storage medium such as CD, CDV, LD, or DVD, or a magnetic storage type such as MO. / Optical reading type storage media, including any storage media that can be read by a computer regardless of electronic, magnetic, optical, or other reading methods.

  In the first to third embodiments, the light modulation device and the optical display device, and the light modulation method and the image display method according to the present invention are as shown in FIG. 1, FIG. 13, and FIG. Although the present invention is applied to the projection display device 100 and the direct view display device 110, the present invention is not limited to this and can be applied to other cases without departing from the gist of the present invention.

2 is a block diagram showing a hardware configuration of a projection display apparatus 100. FIG. 2 is a diagram illustrating a configuration of a relay lens 16. FIG. FIG. 4 is a diagram illustrating an operation principle of the relay lens 16. 3 is a block diagram illustrating a hardware configuration of a display control device 200. FIG. 6 is a diagram illustrating a data structure of a control value registration table 400. FIG. It is a figure which shows the data structure of the control value registration table 420R. It is a flowchart which shows a display control process. It is a figure for demonstrating a tone mapping process. It is a figure which shows the case where the transmittance | permeability T2 of a color modulation light valve is provisionally determined. It is a figure which shows the case where the reflectance T1 'of a brightness | luminance modulation light valve is calculated per pixel of a color modulation light valve. It is a figure which shows the case where the reflectance T1 of each pixel of a brightness | luminance modulation light valve is determined. It is a figure which shows the case where the transmittance | permeability T2 of each pixel of a color modulation light valve is determined. 2 is a block diagram illustrating a hardware configuration of a direct-view display device 110. FIG. 6 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction. FIG. It is a figure for demonstrating the image observation state of the direct-view type display apparatus 110 which has a large reflective color liquid crystal panel 66. FIG. It is a figure for demonstrating the image observation state of the direct-view type display apparatus 110 which has a large reflective color liquid crystal panel 66. FIG. 6 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction. FIG. It is a figure which shows the case where the projection type display apparatus 100 is comprised without using the polarizing beam splitter 52. FIG. It is a figure which shows the case where the projection type display apparatus 100 is comprised using DMD56. It is a figure which shows the data structure of the input value registration table. It is a figure which shows the data structure of the input value registration table 460. 6 is a cross-sectional view of the reflective color liquid crystal panel 66 in the optical axis direction. FIG. It is a figure which shows the pixel surface of each pixel of a transmissive liquid crystal light valve. It is a figure which shows the structure of the optical path of the 1st light modulation element in a projection type display apparatus of patent document 1, and a 2nd light modulation element. It is a figure which shows the pixel surface of each pixel of a reflection type light modulation element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Projection type display apparatus, 110 ... Direct view type display apparatus, 10 ... Light source, 10a ... Lamp, 10b ... Reflector, 12 ... Brightness distribution equalization part, 12a, 12b ... Fly eye lens, 12c ... Polarization conversion element, 12d ... Condensing lens, 14... Color modulation unit, 40R to 40B, 40RB... Transmissive liquid crystal light valve, 42R, 42G, 42B _{1 to} 42B ₃ , 42RB ... field lens, 44a, 44b. 48 ... Dichroic prism, 16 ... Relay lens, 18 ... Luminance modulator, 50 ... Reflective liquid crystal light valve, 52 ... Polarization beam splitter, 54 ... λ / 4 plate, 56 ... DMD, 58 ... TIR prism, 60 ... Polarizing plate , 20 ... projection unit, 62 ... transmissive liquid crystal light valve, 64 ... field lens, 6 6 ... reflective color liquid crystal panel, 501 ... polarizing plate, 502 ... phase difference plate, 503 ... front glass substrate, 504 ... color filter, 505 ... common electrode, 506 ... liquid crystal, 507 ... reflective pixel electrode, 508 ... thin film transistor, 509 ... Subsequent glass substrate, 510 ... Uneven portion, 511 ... Fresnel lens, 512 ... Ring zone, 70 ... CPU, 72 ... ROM, 74 ... RAM, 78 ... I / F, 79 ... Bus, 80 ... Light valve driving device, 82 ... Storage device, 199 ... Network, 400, 400R to 400G, 420R to 420G ... Control value registration table, 440,460 ... Input value registration table, 112a, 112b ... Fly eye lens, 112d ... Condensing lens, 130 ... No. 1 light modulation element, 140 ... second light modulation element

Claims (11)

A first light modulation element that modulates light; and a second light modulation element that receives light from the first light modulation element and modulates light; and the first light modulation element and the second light modulation element A device for modulating light from a light source via
The second light modulation element is constituted by a reflection type light modulation element,
A relay lens for forming an optical image of the first light modulation element on a light receiving surface of the second light modulation element is provided on an optical path between the first light modulation element and the second light modulation element. Light modulation device. A light source, light separating means for separating light from the light source into light of a plurality of different specific wavelength regions, and a plurality of first light modulation elements that respectively enter the light separated by the light separating means and modulate the light A light combining means for combining the light from each of the first light modulation elements, and a second light modulation element for receiving the light from the light combining means and modulating the light, and each of the first light modulation elements, An apparatus for displaying an image by modulating light from the light source via a second light modulation element,
The second light modulation element is constituted by a reflection type light modulation element,
An optical system comprising: a relay lens that forms an optical image of each first light modulation element on a light receiving surface of the second light modulation element on an optical path between the light combining unit and the second light modulation element. Display device. In claim 2,
An optical display device, wherein the second light modulation element is constituted by a reflective liquid crystal display element. In claim 2,
An optical display device, wherein the second light modulation element is constituted by DMD. In any one of Claims 2 thru | or 4,
The second light modulation element is composed of a reflective light modulation display panel that modulates light and displays an image,
The reflection type light modulation display panel has an optical diffusion structure. In claim 5,
The reflection type light modulation display panel has a light diffusion structure for diffusing light so as to almost converge toward a predetermined direction. In any one of Claim 5 and 6,
An optical display device, wherein a concavo-convex portion having a light diffusion function is formed on a reflection surface of the reflection type light modulation display panel. In claim 7,
A plurality of concavo-convex portions are formed on the reflection surface of the reflective light modulation display panel, and the cross-sectional shape of the concave portion or the convex portion in each concavo-convex portion is asymmetrical when viewed from the apex, and Alternatively, an optical display device characterized in that the degree of asymmetry is changed according to the distance from the vicinity thereof. In any one of Claims 5 thru | or 8,
An optical display device comprising a Fresnel lens provided on the reflective light modulation display panel. A first modulation step for modulating light from the light source via the first light modulation element; and a second modulation step for modulating light from the first light modulation element via the second light modulation element. , A method of modulating light from the light source,
The second light modulation element is a reflective light modulation element,
An optical image of the first light modulation element is formed on a light receiving surface of the second light modulation element through a relay lens in an optical path between the first light modulation element and the second light modulation element. Light modulation method. A light separation step for separating the light from the light source through a light separation means for separating the light into a plurality of different specific wavelength regions, and for each separated light from the light separation means, through the first light modulation element A first modulation step for modulating the separated light, a light synthesis step for synthesizing the separated light from each of the first light modulation elements via light synthesis means for synthesizing light, and a second light modulation element for A second modulation step of modulating the light from the light combining means, and modulating the light from the light source to display an image,
The second light modulation element is a reflective light modulation element,
An image display characterized in that an optical image of each first light modulation element is formed on a light receiving surface of the second light modulation element via a relay lens in an optical path between the light combining means and the second light modulation element. Method.

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