JP2004219727A - Color correction filter and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem; when a color correction filter such as a filter for reflecting a yellow component to expand a color reproduction range is introduced in a projection type display device, the color purity of red, green, and blue is improved but the chromaticity of white changes greatly to be of a property deviating from a blackbody locus, and when this deviation is corrected by an electric circuit, the contrast performance deteriorates. <P>SOLUTION: The color correction filter is provided with a multi-layer film formed on both surfaces or one surface of a glass substrate. The multilayer film has: a characteristic of cutting off the yellow component or the yellow component and cyan component to improve the color purity of red, green and blue; and a characteristic showing a half mirror performance in the wavelength region of the blue component corresponding to at least the complementary color of the yellow component for correcting the chromaticity of white. Thus, the improvement on the color reproduction range can be made compatible with the chromaticity correction of white without deteriorating a contrast performance, and a projected image can be displayed in favorable quality. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention provides a color correction filter that selectively transmits or reflects wavelengths by laminating a multilayer film on a parallel plane substrate, and enlarges and projects an optical image formed on a light valve on a screen using the color correction filter. The present invention relates to a projection type display device.
[0002]
[Prior art]
Projection display devices that form an optical image corresponding to a video signal on a light valve in order to obtain a large screen image, irradiate the optical image with light, and enlarge and project the image on a screen with a projection lens have been well known. I have. By using three light valves corresponding to the three primary colors of red, green and blue, it is possible to display a projected image with high luminance, high resolution and good color reproducibility.
[0003]
FIG. 11 shows a configuration example of a projection display device using three light valves. Radiation light from a lamp 1 as a light source is converted into substantially parallel light by a concave mirror 2 and condensed on light valves 12R, 12G, and 12B by an illumination optical system 9. The illumination optical system 9 includes lens arrays 4 and 5 for converging a light source image and illuminating the light valves 12R, 12G, and 12B with high efficiency and high uniformity, condensing lenses 6, 8, and an illumination light introducing mirror. 7 is comprised. Light from the illumination optical system 9 passes through a total reflection prism 10 and is separated by a color separation / combination prism 11 that separates white light into red, blue, and green primary color lights, and then the corresponding three light valves 12R and 12G. , 12B. The three light valves 12R, 12G, and 12B are reflection-type light valves that modulate the traveling direction of light in accordance with each video signal to form an optical image. The reflected lights from the light valves 12R, 12G, and 12B are combined again into one by the color separation / combination prism 11, transmitted through the total reflection prism 10, and enlarged and projected by the projection lens 13.
[0004]
When it is necessary to realize a color reproduction range that cannot be achieved only by the color separation / combination prism 11, the color correction filter 3 is introduced between the light source 1 and the total reflection prism 10. In the example of FIG. 11, the color correction filter 3 is disposed between the concave mirror 2 and the lens array 4.
[0005]
The color correction filter 3 may have a spectral transmittance characteristic shown in FIG. 12, for example. The color correction filter 3 reflects about 85% of a yellow component having a peak wavelength of 585 nm. By using such a color correction filter 3, the yellow component of the green component and the yellow component of the red component of the three primary color lights are cut, so that the color purity of the green light and the red light can be arbitrarily and rapidly increased. Can be improved.
[0006]
FIG. 13 shows an example of the spectral spectrum of the output light of the projection display device shown in FIG. 11 using the color correction filter 3 as described above, and FIG. 13 shows an xy chromaticity coordinate graph of white light and red, green, and blue primary color lights. Is shown in FIG.
[0007]
[Patent Document 1]
JP-A-5-83722 [Patent Document 2]
JP-A-7-72450 [Patent Document 3]
Japanese Patent No. 3329070
[Problems to be solved by the invention]
In the projection display apparatus shown in FIG. 11, the color correction filter 3 increases the area of the triangle connecting the chromaticity points of the three primary colors of red, green, and blue shown in FIG. 14, thereby improving the color reproduction range. I have. However, on the other hand, the chromaticity coordinates of the white light tend to move away from the black body locus curve, which is generally used as the reference value of the white chromaticity, as the color reproduction range of the three primary colors is expanded.
[0009]
Conventionally, to solve this problem, means for adjusting the output intensities of red, green, and blue using an electric circuit has been used. However, according to this method, the chromaticity of the black display cannot be corrected, and one of the three primary colors is attenuated only in the white display, so that the contrast ratio represented by the ratio of the brightness of the white display to the brightness of the black display. Decreases.
[0010]
In the conventional example shown in FIGS. 11 to 14, for example, when white light corresponding to a color temperature of 6500 K on a black body locus is adjusted by an electric circuit, the contrast is reduced by about 40%.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to provide a projection-type display device which achieves both improvement of the color reproduction range and correction of the chromaticity of white light without deteriorating the contrast performance, and has good display quality.
[0012]
[Means for Solving the Problems]
In order to solve this problem, a color correction filter according to the present invention has a characteristic of reflecting at least one peak wavelength by at least 40% or more, and has an average transmission in a wavelength region of a complementary color component with respect to the color component having the at least one peak wavelength. It has a half mirror characteristic in which the ratio is in the range of 30% or more and 70% or less.
[0013]
Further, the projection display device of the present invention includes a light source, a light valve as an image forming means, an illumination optical system for condensing light emitted from the light source on the light valve, and an optical image formed on the light valve. A projection lens for enlarging and projecting on a screen is provided, and the color correction filter is arranged between a light source and an illumination optical system or in an optical path of the illumination optical system.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0015]
(Embodiment 1)
FIG. 1 shows a schematic configuration of a projection display apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is a lamp as a light source, 9 is an illumination optical system, 11 is a color separation / combination prism, and 12R. , 12G and 12B are light valves, 13 is a projection lens, and 21 is a color correction filter. The configuration other than the color correction filter 21 is the same as that of the conventional example shown in FIG.
[0016]
The light valves 12R, 12G, and 12B are of a reflection type in which mirror elements are arranged in a matrix for each pixel, and the light traveling direction is modulated according to a video signal to form an optical image as a change in reflection angle.
[0017]
The lamp 1 uses an ultra-high pressure mercury lamp, and the concave mirror 2 is a parabolic mirror having a parabolic cross section. By arranging the illuminant center of the lamp 1 so as to be located substantially near the focal point of the concave mirror 2, the radiated light output from the lamp 1 is converted into substantially parallel light. The concave mirror 2 is formed by forming an optical multilayer film that transmits infrared light and reflects visible light on the inner surface of a glass material. The light output from the concave mirror 2 enters the illumination optical system 9 via a color correction filter 21.
[0018]
The illumination optical system 9 includes lens arrays 4 and 5 for converging a light source image and illuminating the light valves 12R, 12G, and 12B with high efficiency and high uniformity, condensing lenses 6, 8, and an illumination light introducing mirror. 7 is comprised. Light output from the concave mirror 2 is brightest near the center near the optical axis, and tends to sharply darken toward the periphery, so that unevenness of luminance remains in the plane. Therefore, the first lens array 4 treats the aperture shape of each subdivided lens as a secondary surface light source and has the same aspect ratio as the effective display surface of the light valves 12R, 12G, and 12B. From each lens, a light source image is formed on each lens of the corresponding second lens array 5 by subdividing it by the number of lens arrays. The output light from the second lens array 5 is superimposed by the second lens array 5 and the condensing lenses 6 and 8 on the light valves 12R, 12G, and 12B, on which the images of the respective lens shapes of the first lens array 4 are superimposed. Is illuminated.
[0019]
By doing so, it is possible to illuminate uniformly and with high light collection efficiency corresponding to the aspect ratio of the light valves 12R, 12G, and 12B.
[0020]
In this case, the aperture shape of each lens of the second lens array 5 corresponds to the size and shape of the arc image of the lamp 1 that has been segmented and imaged by the first lens array 4. By optimizing the brightness distribution so as to be as close-packed as possible, illumination with higher light-collecting efficiency can be realized.
[0021]
The illumination light emitted from the illumination optical system 9 is configured to enter the total reflection prism 10. The total reflection prism 10 is composed of two prisms, and forms a very thin air layer on the adjacent surfaces of the prisms. When the illuminating light is incident on the air layer, the illuminating light is incident on the air layer at an angle greater than the critical angle, is totally reflected, travels obliquely toward the light valves 12R, 12G, and 12B. The light reflected from 12G and 12B is set at an angle so as to enter and pass through the air layer at an angle equal to or smaller than the critical angle and enter the projection lens 13. By providing the total reflection prism 10 in this way, the entire optical system can be made compact.
[0022]
A color separation / combination prism 11 is arranged between the total reflection prism 10 and the light valves 12R, 12G, 12B, and three light valves 12R, 12G, 12B are used for red, green, and blue. The color separation / combination prism 11 includes three prisms, and a blue reflection dichroic mirror and a red reflection dichroic mirror are formed on the adjacent surfaces of each prism.
[0023]
The light incident from the total reflection prism 10 is first reflected only by the blue reflection dichroic mirror, and then enters the blue light valve 12B. Next, the light transmitted through the blue reflection dichroic mirror is reflected only by the red reflection dichroic mirror and is incident on the red light valve 12R. The green light transmitted through both the blue reflection dichroic mirror and the red reflection dichroic mirror enters the green light valve 12G. After being reflected by the corresponding light valves 12R, 12G, and 12B, the three colors of light are combined again by the blue reflection dichroic mirror and the red reflection dichroic mirror, and enter the total reflection prism 10. As described above, the white light is separated and synthesized into the three primary colors of red, blue, and green, and by using the three light valves 12R, 12G, and 12B corresponding to the respective video signals, a high-definition, full-color projected image is obtained. Can be displayed.
[0024]
Of the illumination light incident on the light valves 12B, 12R, and 12G, light corresponding to white display is transmitted through the total reflection prism 10 and the projection lens 13 and is enlarged and projected on a screen (not shown). On the other hand, light corresponding to black display travels outside the effective diameter of the projection lens 13 and does not reach the screen.
[0025]
The spectral transmittance characteristics of the color correction filter 21 are shown in FIGS. As shown in FIG. 3A, the color correction filter 21 has a first dielectric multilayer film having a spectral transmittance characteristic of reflecting about 85% of a yellow component having a peak wavelength of 585 nm and reflecting about 85% as shown in FIG. On the other side, as shown in FIG. 3B, a second dielectric multilayer film exhibiting a spectral transmittance characteristic that is approximately flat in a wavelength band of 420 to 560 nm and has an average transmittance of about 50% is formed. Thus, the spectral transmittance characteristics as shown in FIG. 2 are shown as a whole. Each of the first and second dielectric multilayer films has an alternating periodic layer structure of Nb ₂ O ₅ as a high refractive index layer and SiO ₂ as a low refractive index layer.
[0026]
In addition, as the high refractive index layer, any one of Ta ₂ O 5, TiO ₂ , ZrO ₂ , ZnS, HfO ₂ , or a mixture thereof may be used. In addition, MgF ₂ may be used as the low refractive index layer.
[0027]
FIG. 4 shows a spectral spectrum of output light of the projection display apparatus shown in FIG. 1 using the color correction filter 21, and FIG. 5 shows an xy chromaticity coordinate graph.
[0028]
The color correction filter 21 has a characteristic of reflecting the yellow component as shown in the conventional example of FIGS. 11 to 14, and from a blue component corresponding to a complementary color of the yellow component to a strong green component which is a characteristic of an ultra-high pressure mercury lamp. It can be seen that the chromaticity of the white light is closer to the locus of the black body as compared with FIG.
[0029]
Accordingly, the chromaticity of the black display also shows a characteristic similar to the locus of the black body, and the color reproduction range is expanded without deteriorating the contrast performance because there is almost no need to adjust the chromaticity in the white display by an electric circuit. be able to.
[0030]
At this time, it is desirable that the reflectance at the peak wavelength of the yellow component is at least 40% or more. If it is less than 40%, the color purity of the green component and the red component cannot be sufficiently improved, and the expansion of the color reproduction range cannot be expected much.
[0031]
The peak wavelength of the yellow light is desirably 570 nm or more and 590 nm or less. When the wavelength is shorter than 570 nm or longer than 590 nm, the amount of light deteriorates more remarkably than the improvement in the color purity of the green component or the red component, and the luminance balance of red, green, and blue is large as a whole. It will collapse. In this case, there is a possibility that it is difficult to achieve both a sufficient color reproduction range and brightness.
[0032]
Further, the average transmittance at 420 to 560 nm is desirably 30% or more and 70% or less. If it is larger than 70%, the chromaticity correction amount of white becomes insufficient in most cases, and if it is smaller than 30%, it becomes excessively conversely corrected, and there is a possibility that the chromaticity correction point departs again from the desired chromaticity point.
[0033]
In the present embodiment, a reflective light valve that modulates the traveling direction of light is used as the light valve. However, a light valve that modulates the polarization direction or scattering state of light, or a light valve that transmits light is used. The same effect is exerted even when is used.
[0034]
(Embodiment 2)
FIG. 6 shows a schematic configuration of a projection display apparatus according to Embodiment 2 of the present invention. In FIG. 6, reference numeral 31 denotes a lamp as a light source, and 33 denotes a color correction filter. Other components and operations are almost the same as those of the configuration shown in FIG.
[0035]
In the present embodiment, a xenon lamp is used as the lamp 31. Output light from the lamp 31 is converted into substantially parallel light by the concave mirror 32, and enters the illumination optical system 39 via the color correction filter 33.
[0036]
The illumination optical system 39 includes a first lens array 34, a second lens array 35, condenser lenses 36 and 38, and an illumination light introducing mirror 37.
[0037]
The illumination light emitted from the illumination optical system 9 enters the color separation / combination prism 41 via the total reflection prism 40, is decomposed into three primary color lights of red, green, and blue, and corresponds to three corresponding light valves 42R, 42G, 42B. The three color optical images formed on the light valves 42R, 42G, and 42B are reflected by the corresponding light valves 42R, 42G, and 42B, respectively, and then combined again by the color separation / combination prism 41, and are totally reflected. The light passes through 40 and is enlarged and projected on a screen (not shown) by a projection lens 43.
[0038]
FIGS. 7 and 8 show the spectral transmittance characteristics of the color correction filter 33 used in the present embodiment. As shown in FIG. 8A, the color correction filter 33 has a first dielectric multilayer film having a spectral transmittance characteristic of reflecting about 95% of a yellow component having a peak wavelength of 575 nm and reflecting about 95% as shown in FIG. As shown in FIG. 3B, the other surface has a characteristic of reflecting about 75% of a cyan component having a peak wavelength of 490 nm, and a substantially flat average transmittance of about 60% in a wavelength band of a blue component of 420 to 470 nm. A second dielectric multilayer film having a spectral transmittance characteristic of is formed, and exhibits a spectral transmittance characteristic as shown in FIG. 7 as a whole.
[0039]
Each of the first and second dielectric multilayer films has an alternating periodic layer structure of Nb ₂ O ₅ as a high refractive index layer and SiO ₂ as a low refractive index layer.
[0040]
In addition, as the high refractive index layer, any one of Ta ₂ O ₅ , TiO ₂ , ZrO ₂ , ZnS, HfO ₂ , or a mixture thereof may be used. In addition, MgF ₂ may be used as the low refractive index layer.
[0041]
FIG. 9 shows a spectral spectrum of output light of the projection display apparatus shown in FIG. 6 using the color correction filter 33, and FIG. 10 shows an xy chromaticity coordinate graph.
[0042]
The color correction filter 33 has a characteristic of transmitting white light in a substantially flat characteristic in a wavelength band of a blue component corresponding to a complementary color of the yellow component, in addition to a characteristic of reflecting the yellow component and the cyan component. It can be seen that the chromaticity is corrected so as to be substantially on the locus of the black body.
[0043]
Accordingly, also in the present embodiment, the chromaticity of the black display similarly shows the chromaticity characteristic substantially on the locus of the black body, and at the same time, there is almost no need to adjust the chromaticity of the white display by an electric circuit. The color reproduction range can be expanded without deterioration.
[0044]
At this time, the peak reflectance of the yellow component and the cyan component is preferably at least 40% or more. If it is less than 40%, the color purity of the red component, the green component and the blue component cannot be sufficiently improved, and the expansion of the color reproduction range cannot be expected much.
[0045]
The peak wavelength of the yellow component is desirably from 570 nm to 590 nm. When the wavelength is shorter than 570 nm or longer than 590 nm, the amount of light deteriorates more remarkably than the improvement in the color purity of the green component or the red component, and the luminance balance of red, green, and blue is large as a whole. It will collapse. In this case, it is difficult to achieve both a sufficient color reproduction range and brightness. Similarly, the peak wavelength of the cyan component is preferably 480 nm or more and 500 nm or less. When the wavelength is shorter than 480 nm or the wavelength is longer than 500 nm, the deterioration of the light amount is more remarkable than the improvement of the color purity of the green component or the blue component. The balance is greatly lost, and it is difficult to achieve both a sufficient color reproduction range and brightness.
[0046]
Further, the average transmittance at 420 to 470 nm, which is a blue component, is preferably 30% or more and 70% or less. If it is larger than 70%, the chromaticity correction amount of white becomes insufficient in most cases, and if it is smaller than 30%, it becomes excessively conversely corrected, and there is a possibility that the chromaticity correction point departs again from the desired chromaticity point.
[0047]
In this embodiment, a reflective light valve that modulates the traveling direction of light is used as the light valve. However, a light valve that modulates the polarization direction and scattering state of light and a light valve that transmits light are used. The same effect is exerted even when is used.
[0048]
【The invention's effect】
As described above, according to the present invention, there is provided a projection display device that can improve the color reproduction range and correct white chromaticity without deteriorating contrast performance, and that can display a projection image with good display quality. Can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention; FIG. 2 is a spectral transmittance characteristic graph of a color correction filter according to an embodiment of the present invention; FIG. 4 is a graph showing a spectral transmittance characteristic of a color correction filter according to an embodiment of the present invention. FIG. 4 is a graph showing a spectral spectral characteristic of output light of a projection display device according to an embodiment of the present invention. An xy chromaticity characteristic graph of a projected image of the display device. FIG. 6 is a schematic configuration diagram of a projection display device according to an embodiment of the present invention. FIG. 7 is a spectral transmittance of a color correction filter according to an embodiment of the present invention. Characteristic graph [FIG. 8] Spectral transmittance characteristic graph of color correction filter according to one embodiment of the present invention [FIG. 9] Spectral spectral characteristic graph of output light of projection type display device according to one embodiment of the present invention [FIG. One embodiment of the present invention Xy chromaticity characteristic graph of the projected image of the projection type display device according to the embodiment [FIG. 11] Schematic configuration diagram of the conventional projection type display device [FIG. 12] Spectral transmittance characteristic graph of the color correction filter in the conventional projection type display device [ FIG. 13 is a graph showing spectral spectrum characteristics of output light in a conventional projection display device. FIG. 14 is a graph showing xy chromaticity characteristics of a projected image in a conventional projection display device.
1, 31 lamp 2, 32 concave mirror 21, 33 color correction filter 9, 39 illumination optical system 11, 41 color separation / combination prism 12R, 12G, 12B, 42R, 42G, 42B light valve 13, 43 projection lens

Claims (13)

A half having a characteristic of reflecting at least one peak wavelength of at least 40% or more, and having an average transmittance in a wavelength region of a complementary color component with respect to the color component of the at least one peak wavelength of 30% or more and 70% or less. A color correction filter having a mirror characteristic. 2. The color correction filter according to claim 1, wherein a color component having a peak wavelength reflected by at least 40% or more is a yellow component. 3. The color correction filter according to claim 2, wherein the peak wavelength of the yellow component is 570 nm to 590 nm. 3. The color correction filter according to claim 2, wherein the wavelength range of the complementary color component is from 420 nm to 560 nm. A dielectric multilayer film having a property of reflecting a yellow component is formed on one surface of a glass substrate, and a dielectric multilayer film having a half mirror characteristic for a wavelength region of a color component complementary to the yellow component is formed on the other surface. 3. The color correction filter according to claim 2, wherein: 2. The color correction filter according to claim 1, wherein the color components of the peak wavelength reflected by at least 40% or more are a yellow component and a cyan component. 7. The color correction filter according to claim 6, wherein the peak wavelength of the yellow component is 570 nm to 590 nm, and the peak wavelength of the cyan component is 480 nm to 500 nm. 7. The color correction filter according to claim 6, wherein the wavelength range of the complementary color component of yellow is from 420 nm to 470 nm. A dielectric multilayer film having a characteristic of reflecting a yellow component is formed on one surface of a glass substrate, and a dielectric multilayer film having a characteristic of reflecting a cyan component and a half mirror characteristic in a wavelength region of a blue component on the other surface. 7. The color correction filter according to claim 6, wherein the color correction filter is formed. The dielectric multilayer film includes a high refractive index layer made of any one of Nb ₂ O ₅ , Ta ₂ O ₅ , TiO ₂ , ZrO ₂ , ZnS, and HfO ₂ , or a mixture thereof, and one of SiO ₂ and MgF ₂ . 10. The color correction filter according to claim 5, wherein the color correction filter has an alternating multilayer structure with a low refractive index layer composed of: A light source, a light valve as an image forming means, an illumination optical system for condensing light emitted from the light source on the light valve, and a projection lens for enlarging and projecting an optical image formed on the light valve on a screen And a color correction filter according to any one of claims 1 to 10, wherein the color correction filter is arranged between the light source and the illumination optical system or in an optical path of the illumination optical system. Display device. 12. The projection display device according to claim 11, wherein the light source uses a mercury lamp. The projection type display device according to claim 11, wherein a xenon lamp is used as a light source.

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