JP2007072401A - Projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type image display device capable of adjusting a display image to a visible brightness without exerting adverse influence on reliability or life of a light source, or else and without bringing about deterioration of contrast and color reproduction in the display image, in regard to the projection type image display device which guides luminous flux emitted from the light source with a lighting optical system, lights a spatial light modulation element, and magnifies and forms the image modulated by the spatial light modulation element by a projective optical system. <P>SOLUTION: A replaceable attenuating optical element 22 that attenuates transmission amount of light of at least a specified wavelength band or a specified polarization component on an outer circumferential side part of a light path of the luminous flux is disposed between the light source 3 and the lighting optical system 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection type image display apparatus that illuminates a spatial light modulation element and enlarges an image displayed by the spatial light modulation element by a projection optical system.

  Conventionally, as shown in FIG. 5, a plurality of spatial light modulation elements 101R, 101G, and 101B are provided, and these spatial light modulation elements 101R, 101G, and 101B are illuminated by an illumination device, and each of the spatial light modulation elements 101R, 101G, and 101B. There has been proposed a projection type image display apparatus that displays an image by enlarging an image modulated by the projection optical system 102 to form an image. The illumination device in such a projection-type image display apparatus includes a light source 103 and an illumination optical system 104 that illuminates the spatial light modulation elements 101R, 101G, and 101B by guiding a light beam from the light source 103. Yes.

  An ultra-high pressure mercury lamp or the like is used as the light source 103 in the illumination device. Further, as the illumination optical system 104, an illumination optical system 104 having an integrator such as a fly eye integrator composed of a pair of fly eye lens arrays 105 and 106 is used in order to equalize the brightness of the light beam from the light source 103 and guide it to the spatial light modulator. Has been.

  That is, in such a projection type image display apparatus, the illumination light emitted from the light source 103 passes through the pair of fly-eye lens arrays 105 and 106, the condenser lens 107, and the relay lens 108, and then enters the first dichroic mirror 109. Incident. In the first dichroic mirror 109, the red component of the illumination light is transmitted and the green component and the blue component are reflected.

  The red component of the illumination light transmitted through the first dichroic mirror 109 is incident on the first polarization beam splitter 113 via the relay lens 110, the mirror 111, and the relay lens 112 for adjusting the optical path length. The red component of the illumination light incident on the first polarization beam splitter 113 is reflected by the reflection film of the first polarization beam splitter 113 and illuminates the spatial light modulation element 101R for red.

  The red component of the illumination light is reflected by the spatial light modulator 101R after being polarization-modulated in accordance with the red component of the display image. The reflected light reenters the first polarization beam splitter 113, passes through the reflective film, and enters the color synthesis prism 114 from the side surface of the color synthesis prism 114.

  On the other hand, the green component and the blue component of the illumination light reflected by the first dichroic mirror 109 are incident on the second dichroic mirror 115. In the second dichroic mirror 115, the blue component of the illumination light is transmitted and the green component is reflected. The green component of the illumination light reflected by the second dichroic mirror 115 is incident on the second polarization beam splitter 116. The green component of the illumination light incident on the second polarization beam splitter 116 is reflected by the reflection film of the second polarization beam splitter 116, and illuminates the green spatial light modulation element 101G.

  The green component of the illumination light is polarized and modulated by the spatial light modulator 101G according to the green component of the display image and reflected. The reflected light reenters the second polarization beam splitter 116, passes through the reflection film, and enters the color synthesis prism 114 from the rear surface portion of the color synthesis prism 114.

  The blue component of the illumination light transmitted through the second dichroic mirror 115 is incident on the third polarization beam splitter 117. The blue component of the illumination light incident on the third polarization beam splitter 117 is reflected by the reflection film of the third polarization beam splitter 117 and illuminates the blue spatial light modulation element 101B.

  The blue component of the illumination light is reflected by the spatial light modulator 101B after being subjected to polarization modulation according to the blue component of the display image. The reflected light reenters the third polarizing beam splitter 117, passes through the reflective film, and enters the color combining prism 114 from the side surface portion of the color combining prism 114.

  The red component, the green component, and the blue component of the illumination light incident on the color synthesis prism 114 are synthesized by the color synthesis prism 114, emitted from the front surface of the color synthesis prism 114, and projected into the projection optical system (projection lens) 102. Is incident on. The projection optical system 102 images incident illumination light on a screen (not shown), and displays an enlarged image of the image displayed by each of the spatial light modulation elements 101R, 101G, and 101B.

  The light source 103 is fixed to the lamp house 118 and can be exchanged from the outside of the outer casing 119 by removing the lid 120 provided on the outer casing 119. The light source 103 is replaced when the light source 103 reaches the end of its life.

  In such a projection-type image display device, when viewing a display image in a bright room, the illumination light that illuminates the spatial light modulation elements 101R, 101G, and 101B is set to high brightness, while the display image is displayed in a dark room. In the case of viewing, it is necessary to suppress the luminance of the illumination light that illuminates the spatial light modulation elements 101R, 101G, and 101B and adjust the luminance so that the display image can be easily viewed.

  As means for adjusting the luminance of illumination light for illuminating the spatial light modulators 101R, 101G, and 101B, conventionally, the output of the light source 103 is adjusted via a power source. That is, it is a means for adjusting the luminance of the illumination light by adjusting the output of the light source 103 by adjusting the amount of current supplied to the light source 103.

  Further, as a means for adjusting the luminance of the illumination light without adjusting the output of the light source 103, adjusting the modulation factor in the spatial light modulation elements 101R, 101G, and 101B is performed.

  In Patent Document 1, the spatial light modulation element 101R, which is a light beam from the light source 103, is adjusted by moving one of the fly-eye lens arrays 105, 106 forming a fly-eye integrator in a direction orthogonal to the optical axis. A configuration for improving the illumination efficiency for 101G and 101B is described. This is intended to improve the illumination efficiency and increase the luminance of the illumination light by matching the illumination range by the illumination optical system with the positions of the spatial light modulation elements 101R, 101G, and 101B. It does not present a means for adjusting the brightness of light.

JP-A-10-115803

  By the way, in the projection type image display apparatus as described above, when adjusting the luminance of the illumination light by adjusting the output of the light source 103, there is a problem of adversely affecting the reliability, life, etc. of the light source 103, 20% The adjustment is limited.

  That is, in a lamp such as an ultra-high pressure mercury lamp used as the light source 103, a temperature condition for stable light emission, a bulb internal pressure condition, and the like are set, but when a lamp output is adjusted via a lamp power source, There is a risk of deviating from these conditions. If the lamp continues to be used in a state deviating from these appropriate temperature conditions, valve internal pressure conditions, etc., there is a risk that reliability, life, etc. may be impaired.

  Further, in the projection type image display apparatus, when adjusting the luminance of the display image by adjusting the modulation factor in the spatial light modulators 101R, 101G, and 101B, the contrast in the display image is deteriorated and the color reproducibility is deteriorated. There is a risk of being invited.

  That is, in the projection type image display device, spectral optics such as the dichroic mirrors 109 and 115 and the dichroic prism 114 are used for color separation and color synthesis of each color light of R (red), G (green) and B (blue). An element is used. Since the characteristics of the dichroic mirrors 109 and 115, the dichroic prism 114, and the like are fixed for each optical element, the color purity of each of the R, G, and B colors and the chromaticity of white in the display image are the spatial light modulation element 101R. , 101G, and 101B.

  Here, if the modulation factors of the spatial light modulation elements 101R, 101G, and 101B are changed for adjusting the luminance of the display image while maintaining the color purity of each color and the chromaticity of white, the spatial light modulation element The dynamic ranges of 101R, 101G, and 101B cannot be fully utilized, and it becomes difficult to secure gradation in the dark part of the display image.

  In addition, such a change in the modulation factor of the spatial light modulators 101R, 101G, and 101B may reduce the color purity reproduction range and lower the color purity.

  Therefore, the present invention is proposed in view of the above-described circumstances, and does not adversely affect the reliability and life of the light source, and also causes deterioration in contrast and color reproducibility in the display image. It is another object of the present invention to provide a projection type image display device that can adjust the display image to a brightness that allows easy viewing.

  In order to solve the above-described problems, a projection-type image display device according to the present invention has any one of the following configurations.

[Configuration 1]
In a projection-type image display apparatus in which a light beam emitted from a light source is guided by an illumination optical system to illuminate a spatial light modulation element and an image modulated by the spatial light modulation element is enlarged and imaged by a projection optical system. Attenuating optical element is provided between the illumination optical system and the optical path for attenuating the transmitted light amount of light of at least a constant wavelength band or a fixed polarization component in the outer peripheral portion of the optical path of the light beam. is there.

  As an attenuating optical element for attenuating the transmitted light amount of light of at least a certain wavelength band or a certain polarization component in the outer peripheral part of the optical path of the light beam, an aperture having an opening in the center part, one side of a transparent substrate, or An interference film formed on both surfaces, a polarizing plate arranged in a rotatable manner, or a combination thereof can be considered. That is, as this attenuating optical element, a combination of an aperture and an interference film, a combination of an aperture and a polarizing plate, a combination of an interference film and a polarizing plate, or an aperture, an interference film and a polarizing plate Combinations are also possible. Further, in the aperture, the outer peripheral side portion of the opening may be a reflecting plate.

[Configuration 2]
In the projection type image display apparatus having the configuration 1, the attenuation optical element is replaceable.

[Configuration 3]
In the projection-type image display device having the configuration 1 or the configuration 2, the attenuation optical element includes a polarizing plate that attenuates the amount of transmitted light of a certain polarization component, and can be rotated around the optical axis. It is characterized by becoming.

  In the projection type image display apparatus according to the present invention, between the light source and the illumination optical system, the transmitted light amount of light having at least a certain wavelength band or a certain polarization component is attenuated in the outer peripheral portion of the optical path of the light beam. Equipped with an attenuating optical element, when viewing a display image in a dark room, the brightness of the illumination light that illuminates the spatial light modulation element is suppressed without reducing the output of the light source, making the display image easy to see Can be adjusted.

  In this projection type image display device, the attenuation optical element can be exchanged to adjust the brightness of the display image and the color balance in the display image according to the surrounding situation (brightness) and the taste of the viewer. It can be performed.

  Further, in this projection type image display apparatus, when the attenuation optical element includes a polarizing plate that attenuates the amount of transmitted light of a certain polarization component, the attenuation optical element can be rotated around the optical axis. Thus, the brightness of the display image can be easily adjusted according to the surrounding situation (brightness).

  That is, the present invention can adjust the brightness of the display image so that the display image is easy to see without adversely affecting the reliability and life of the light source, and without causing deterioration of contrast and color reproducibility in the display image. The projection type image display apparatus made can be provided.

  Hereinafter, the configuration of the projection type image display apparatus according to the present invention will be described in detail.

  FIG. 1 is a plan view showing a configuration of a projection type image display apparatus according to the present invention.

  As shown in FIG. 1, the projection type image display device includes a plurality of spatial light modulation elements 1R, 1G, and 1B. The spatial light modulation elements 1R, 1G, and 1B are illuminated by an illumination device, and each spatial light modulation element is illuminated. This is a projection type image display device that displays an image by enlarging and forming an image modulated by the elements 1R, 1G, and 1B by the projection optical system 2. The illumination device in the projection type image display apparatus includes a light source 3 and an illumination optical system 4 that guides a light beam from the light source 3 and illuminates the spatial light modulation elements 1R, 1G, and 1B.

  As the light source 3 in the illumination device, an ultra-high pressure mercury lamp or the like can be used. Further, as the illumination optical system 4, an illumination optical system 4 having an integrator such as a fly-eye integrator composed of a pair of fly-eye lens arrays 5 and 6 is used in order to equalize the luminance of the light beam from the light source 3 and guide it to the spatial light modulator. can do. In the illumination optical system 4, the light beam emitted from the light source 3 is converted into substantially parallel light by the paraboloid reflector 3 a and is incident on the first fly-eye lens array 5. The light beam that has passed through the first fly-eye lens array 5 is condensed on each of the opposing cells of the second fly-eye lens array 6. The light beam that has passed through the second fly-eye lens array 6 is incident on the PBS array 7. This PBS array 7 is a PS synthesis prism, which separates the non-polarized light transmitted through the second fly-eye lens array 6 into a P-polarized component and an S-polarized component, and a λ / 2 plate (half-wave plate) By converting the S-polarized component into the P-polarized component (or converting the P-polarized component into the S-polarized component), the optical element aligns the polarization direction of the illumination light in a fixed direction.

  In this illumination optical system 4, the shape of the light beam that illuminates each of the spatial light modulation elements 1 R, 1 G, and 1 B serving as the illumination region by the fly eye integrator including the fly eye lens arrays 5 and 6 is the first fly eye lens. A similar image is formed on each cell of the array 5, and the images of all the cells are superimposed.

  The light beam that has passed through the PBS array 7 is incident on the first dichroic mirror 10 via the condenser lens 8 and the relay lens 9. In the first dichroic mirror 10, the red component of the illumination light is transmitted and the green component and the blue component are reflected.

  The red component of the illumination light transmitted through the first dichroic mirror 10 is incident on the first polarization beam splitter 14 via the relay lens 11, the mirror 12 and the relay lens 13 for adjusting the optical path length. The red component of the illumination light incident on the first polarization beam splitter 14 is reflected by the reflection film of the first polarization beam splitter 14 to illuminate the red spatial light modulator 1R.

  The red component of the illumination light is reflected by the spatial light modulator 1R after being polarization-modulated according to the red component of the display image. The reflected light reenters the first polarizing beam splitter 14, passes through the reflective film, and enters the color combining prism 15 from the side surface portion of the color combining prism 15.

  On the other hand, the green component and the blue component of the illumination light reflected by the first dichroic mirror 10 are incident on the second dichroic mirror 16. In the second dichroic mirror 16, the blue component of the illumination light is transmitted and the green component is reflected. The green component of the illumination light reflected by the second dichroic mirror 16 is incident on the second polarization beam splitter 17. The green component of the illumination light incident on the second polarization beam splitter 17 is reflected by the reflection film of the second polarization beam splitter 17 and illuminates the green spatial light modulator 1G.

  The green component of the illumination light is reflected by the spatial light modulator 1G after being polarization-modulated according to the green component of the display image. The reflected light reenters the second polarizing beam splitter 17, passes through the reflective film, and enters the color combining prism 15 from the rear surface portion of the color combining prism 15.

  The blue component of the illumination light transmitted through the second dichroic mirror 16 is incident on the third polarization beam splitter 18. The blue component of the illumination light incident on the third polarization beam splitter 18 is reflected by the reflective film of the third polarization beam splitter 18 and illuminates the blue spatial light modulation element 1B.

  The blue component of the illumination light is reflected by the spatial light modulator 1B after being subjected to polarization modulation according to the blue component of the display image. The reflected light reenters the third polarizing beam splitter 18, passes through the reflective film, and enters the color combining prism 15 from the side surface portion of the color combining prism 15.

  The red component, the green component, and the blue component of the illumination light incident on the color combining prism 15 are combined in the color combining prism 15 and emitted from the front surface of the color combining prism 15, and the projection optical system (projection lens) 2. Is incident on. The projection optical system 2 images incident illumination light on a screen (not shown), and displays an enlarged image of the image displayed by each of the spatial light modulation elements 1R, 1G, 1B.

  Each optical component constituting the projection type image display apparatus is positioned and held by an optical base (not shown). Further, the color synthesizing prism 15 and the polarization beam splitters 14, 17, and 18 are bonded to each other through a spacer glass so that the relative positions are not shifted. Each spatial light modulator 1R, 1G, 1B is positioned so as to be a focus position of the projection optical system 2.

  The light source 3 is fixed to the lamp house 19 and can be exchanged from the outside of the outer casing 20 by removing the lid 21 provided on the outer casing 20. The replacement of the light source 3 is performed when the light source 3 reaches the end of its life.

  FIG. 2 is a cross-sectional view showing a configuration of a lamp house in the projection type image display apparatus.

  As shown in FIG. 2, the lamp house 19 has an attenuation optical that attenuates the amount of transmitted light of at least a constant wavelength band or a constant polarization component in at least the outer peripheral portion of the optical path of the light beam emitted from the light source 3. Element 22 is attached.

  FIG. 3 is a front view showing various configurations of an aperture serving as an attenuation optical element.

  As the attenuating optical element 22, as shown in FIG. 3, an aperture 22b having an opening 22a in the central portion is used as an attenuating optical element 22 that blocks the light beam regardless of the polarization direction in the entire wavelength band at the outer peripheral portion of the light beam. it can.

  As the shape of the opening 22a in the aperture 22b, in addition to the circular shape shown in (a) in FIG. 3, a regular octagon (polygon) shown in (b) in FIG. 3, or (c) in FIG. The rectangle shown in FIG. 3 may be omitted, or the rectangle shown in FIG. Further, as shown in (e) of FIG. 3, the opening 22a may have a non-target shape with respect to the center of the optical axis.

  Thus, by preparing various apertures 22b having different sizes and shapes of the opening 22a and selecting and installing them according to the use of the projection type image display device, the same light source 3 and lamp house 19 are used. Thus, it is possible to configure a projection type image display apparatus in which the brightness of the display image is adapted to the user's desire.

  Further, by using the aperture 22b, the illumination light from the light source 3 is narrowed, the F number of the illumination optical system 4 is increased, and the incident angle of the illumination light with respect to each polarization beam splitter 14, 17, 18 is suppressed. Since the polarization separation characteristics of the polarization beam splitters 14, 17, and 18 are improved, the contrast of the display image can be improved.

  The aperture 22b may be used by combining a plurality of apertures 22a having different shapes.

  In addition, the aperture 22b may have an outer peripheral side portion of the opening 22a as a reflection plate. In this case, the light beam emitted from the light source 3 and blocked by the outer peripheral portion of the opening 22a is returned to the light source 3 side and reused, so that light loss can be suppressed and the contrast of the display image can be suppressed. Can be improved.

  FIG. 4 is a cross-sectional view showing the configuration of the interference film serving as the attenuation optical element.

  Further, as shown in FIG. 4, the attenuating optical element 22 attenuates light in a certain wavelength band regardless of the polarization direction over the entire region of the illumination light beam, and as shown in FIG. An interference film (dichroic film) 22d made of a body may be formed. The interference film 22d can be provided on the surface of the transparent substrate 22c by a manufacturing method such as vapor deposition. By using the attenuation optical element 22 having such an interference film 22d, the color temperature and color purity of the display image can be adjusted.

  In the case where the interference films 22d are formed on both surfaces of the transparent substrate 22c, the characteristics of the entire attenuation optical element 22 can be finely adjusted by making the characteristics of the interference films on each surface different from each other. Fine color adjustment of the image is possible.

  Further, as shown in FIG. 4, such an interference film 22d and the above-described aperture 22b may be used in combination. In this case, both the effect of narrowing the illumination light by the aperture 22b and the effect of adjusting the color temperature by the interference film 22d can be obtained.

  Further, as the attenuating optical element 22, a polarizing plate can be used as an element that attenuates the amount of transmitted light of a certain polarization component for the entire wavelength band in the entire region of the illumination light beam. In this case, it is desirable that the attenuation optical element 22 be disposed so as to be rotatable around the optical axis. In addition, as this polarizing plate, it is desirable to use the wire grid polarizing plate which is a reflection type polarizing plate.

  Further, as the attenuating optical element 22, a combination of the aperture 22b and the polarizing plate, a combination of the interference film 22d and the polarizing plate can be used, and further, the aperture 22b, the interference film 22d, and It is good also as what combined the polarizing plate.

  The attenuating optical element 22 can be exchanged. By making the attenuation optical element 22 replaceable, the user of the projection type image display apparatus can adjust the brightness and color temperature of the display image according to the purpose of use and preference by replacing the attenuation optical element 22. .

It is a top view which shows the structure of the projection type image display apparatus which concerns on this invention. It is sectional drawing which shows the structure of the lamp house in the said projection type image display apparatus. It is a front view which shows the various structure of the aperture used as the attenuation | damping optical element in the said projection type image display apparatus. It is sectional drawing which shows the structure of the interference film | membrane used as the attenuation | damping optical element in the said projection type image display apparatus. It is a top view which shows the structure of the conventional projection type image display apparatus.

Explanation of symbols

1R spatial light modulation element for red 1G spatial light modulation element for green 1B spatial light modulation element for blue 2 projection optical system 3 light source 4 illumination optical system 5 first fly eye lens array 6 second fly eye lens array 22 attenuation optics Element 22a Opening 22b Aperture 22c Transparent substrate 22d Interference film

Claims (3)

In a projection-type image display device that guides a light beam emitted from a light source by an illumination optical system to illuminate a spatial light modulation element, and enlarges and forms an image modulated by the spatial light modulation element by a projection optical system,
An attenuating optical element is provided between the light source and the illumination optical system to attenuate a transmitted light amount of light having at least a constant wavelength band or a constant polarization component in an outer peripheral side portion of the optical path of the light beam. A projection type image display device as a feature. The projection type image display device according to claim 1, wherein the attenuation optical element is replaceable. The attenuating optical element includes a polarizing plate that attenuates the amount of transmitted light of a predetermined polarization component, and is capable of rotating around an optical axis. The projection type image display apparatus according to claim 2.