JP2004333829A - Projection-type display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-contrast, high image quality projection-type display. <P>SOLUTION: The projection-type display comprises photolysis means 105, 106 for decomposing luminous flux that is generated from a light source 101 and passes through an integrator optical system consisting of a first lens array 102, a second lens array 103, and a superimposed lens 104 into red, green, and blue; light bulbs 112, 113, 114 for optically modulating the decomposed luminous flux to red, green, and blue; and a photosynthesis means 115 for synthesizing each modulated color luminous flux for forming a color image. In the projection-type display, a light-shielding means 1 for limiting the incident angle to the light bulb for a specific color is provided, thus achieving a high-contrast display, without causing brightness to be reduced by securing the balance of each color. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projection display device that projects image light on a screen.
[0002]
[Prior art]
A light output from a light source is applied to a light valve via an illumination optical system to modulate the light into image light, and a projection type display device that projects the light onto a screen by a projection unit uses a transmission type light valve. And a method using a reflection-type light valve. FIG. 1 is a schematic diagram showing a configuration of a projection type display device using a conventional reflection type light valve.
[0003]
In FIG. 1, reference numeral 101 denotes a light source, which includes a lamp 101a and a parabolic mirror 101b. The lamp 101a is arranged at the focal position of the parabolic mirror 101b, and emits light substantially parallel to the optical axis O from the opening 101c. Light emitted from the opening 101c sequentially passes through an integrator optical system formed by a first lens array 102, a second lens array 103, and a superimposing lens 104 in which a plurality of lens cells are arranged. Thereby, the light beam of the light source 101 is efficiently and uniformly irradiated on the effective opening of the light valve described later.
[0004]
Reference numeral 105 denotes a group of dichroic mirrors for separating the light beam of the light source 101 for each predetermined wavelength, and includes two dichroic mirrors 105a and 105b. The dichroic mirror group 105, together with a dichroic mirror 106 described later, constitutes a light decomposing unit that decomposes a light beam from the light source 101 into three colors of red light, green light, and blue light having different wavelength ranges. The dichroic mirrors 105a and 105b are arranged so that the reflection surfaces are orthogonal to each other so that the reflection surfaces make an angle of 45 ° with respect to the optical axis, and the axial light passing through the superimposing lens 104 is incident on the intersection. . In the example shown in this figure, the dichroic mirror 105a reflects blue light upward in the drawing, and the dichroic mirror 105b reflects green light and red light downward in the drawing. The traveling direction of the blue light reflected by the dichroic mirror 105 a is bent by 90 ° by the mirror 107, passes through the field lens 117, and is incident on a polarizing beam splitter (hereinafter, referred to as PBS) 109. The field lens 117 is provided in order to make the light beam from the light source 101 a telecentric light beam and reduce errors in the projected image.
[0005]
On the other hand, the traveling directions of the green light and the red light reflected by the dichroic mirror 105 b are turned 90 ° by the mirror 108, and further separated by the dichroic mirror 106. In the example shown in this figure, the dichroic mirror 106 reflects green light and transmits red light, and the green light reflected by the dichroic mirror 106 passes through the field lens 118 and enters the PBS 110. The red light transmitted through the dichroic mirror 106 passes through the field lens 119 and enters the PBS 111. In this example, an illumination optical system is configured by the above-described integrator optical system, optical decomposition means, field lens, and PBS, and converges light from the light source 101 onto each light valve.
[0006]
The traveling directions of the blue, green, and red light beams are bent by 90 degrees by the corresponding PBSs 109, 110, and 111, respectively, and are incident on light valves 112, 113, and 114 formed of liquid crystal panels. At this time, the polarized light components unnecessary for the illumination of the light valves 112, 113, 114 have been removed by the PBSs 109, 110, 111. The blue, green, and red light fluxes modulated by the light valves 112, 113, and 114 enter the PBSs 109, 110, and 111 again, pass through the PBSs 109, 110, and 111, and remove polarization components unnecessary for screen projection. After that, the light enters the cross dichroic prism 115. In the example shown in this figure, blue light enters from above in the drawing, red light enters from below in the drawing, and green light enters from the right in the drawing.
[0007]
The blue light that has entered the cross dichroic prism 115 is reflected by the reflection surface 115a, the red light is reflected by the reflection surface 115b toward the projection lens 116, and the green light passes through the reflection surfaces 115a and 115b and travels straight. The red light fluxes are color-synthesized, and projected onto a screen (not shown) by a projection lens 116 as a projection unit.
[0008]
Next, a method using a transmission type light valve will be described. FIG. 5 is a schematic diagram showing a configuration of a projection display device using a conventional transmission light valve. When a transmissive light valve is used, the incidence surface on which the light beam enters the light valve and the exit surface of the light beam guided from the light valve to the projection lens are different, so that the PBS is unnecessary in the illumination optical system. Note that a polarizing plate (not shown) is provided on the incident surface side and the emission surface side of each light valve, and takes out only a predetermined polarized light from the light beam instead of the PBS. Further, in the example shown in this figure, the dichroic mirror 123 is one that reflects only red light, and the red light is reflected by the dichroic mirror 123, the traveling direction is bent 90 ° in the upward direction in the drawing, and green light and blue light are reflected. The light passes through the dichroic mirror 123 and travels straight.
[0009]
The red light reflected by the dichroic mirror 123 is further turned 90 ° rightward in the drawing by the mirror 107 and then enters the light valve 114 via the field lens 119. The dichroic mirror 124 is of a type that reflects only green light. Of the green light and blue light transmitted through the dichroic mirror 123, the green light is reflected by the dichroic mirror 124 and the traveling direction is bent 90 ° upward in the drawing. The blue light passes through the dichroic mirror 124 and travels straight. The green light reflected by the dichroic mirror 124 enters the light valve 113 via the field lens 118. On the other hand, for blue light, a relay optical system 128 in which a first relay lens 125, a second relay lens 126, and a third relay lens 127 are combined to prevent a reduction in light use efficiency due to an increase in the optical path length. Light is incident on the light valve 112. The red, green, and blue luminous fluxes incident on each light valve are color-combined by the cross dichroic prism 115, and are projected on a screen (not shown) by the projection lens. A mirror 129 is arranged between the first lens array 102 and the second lens array 103, and the optical path from the light source 101 is bent by 90 °. Other configurations are the same as those in FIG.
[0010]
Since the reflection and transmission characteristics of the cross dichroic prism 115 differ depending on the wavelength and the polarization plane of the incident light, it is known that a so-called color shading phenomenon occurs in which the right and left colors differ in the projected image. Accordingly, a method has been devised for preventing color shading by converting red light, blue light to S-wave, and green light to P-wave so that red light, blue light, and green light pass through the cross dichroic prism 115 evenly. However, when a projection screen composed of a Fresnel lens and a lenticular lens is used, the reflectance of the S wave and the P wave differs depending on the incident angle to the projection screen, so that the color unevenness in which the green color becomes dark at the end of the image. Occurs. Patent Literature 1 discloses a method for preventing the above-described color unevenness by providing a light blocking unit that restricts an optical path of green light.
[0011]
Further, it is known that the liquid crystal panel used for the light valves 112, 113, and 114 has a so-called viewing angle characteristic in which contrast changes depending on the angle of incident light or the like. A method is disclosed in which an attenuating plate for attenuating a part of an incident light beam is provided in accordance with the angular characteristics to prevent the deterioration of contrast caused by the viewing angle characteristics of the liquid crystal panel. Further, in Patent Document 3, an attenuating plate having wavelength selectivity is used to selectively attenuate at least one of the color lights, and light is blocked in accordance with the viewing angle characteristics of the liquid crystal panel. A method for improving the contrast without affecting the image quality is disclosed.
[0012]
[Patent Document 1]
JP-A-9-93598
[Patent Document 2]
JP 2001-222002 A
[Patent Document 3]
JP 2003-107579 A
[0013]
[Problems to be solved by the invention]
In the case of a projection display device using a reflection-type light valve, if a glass material having a large photoelastic constant is used for the PBS, the polarization state changes inside the PBS, and sufficient polarization separation performance cannot be secured. This causes a decrease in contrast. Therefore, in order to ensure high contrast, it is necessary to use a glass material having a small photoelastic constant. However, a glass material having a small photoelastic constant has a lower transmittance of blue light on a shorter wavelength side than light on a longer wavelength side, such as red and green, and causes a shortage of a blue component required for illumination of a light valve. However, the image quality is deteriorated such that the color is yellowish. In an optical system that requires particularly high contrast, a plurality of PBSs may be used for each optical path as shown in FIG. 2, but this phenomenon occurs more remarkably because the distance of light passing through the glass material becomes longer. .
[0014]
Therefore, in order to correct the yellow tint, a method of reducing the light use efficiency in the red and green regions by electrically controlling the light valve has been proposed. FIG. 3 shows the relationship between color correction and brightness / contrast by electrical control of the light valve. Before the color correction (FIG. 3A), the brightness (ON light level) in the brightest modulation state of the projection display device is A, and the brightness (OFF light level) in the darkest modulation state is C. After the color correction (FIG. 3B), the ON light levels of the red light and the green light become k × A (k <1) due to the correction, which is almost the same as the blue light, but the OFF light level is corrected. It is still C. The contrast of the projection display device is represented by ON light level / OFF light level, and the contrast after correction is k × A / C (k <1) for red light and green light, and the contrast A / C before correction is obtained. C is lower than C. That is, with this control method, the OFF light level cannot be reduced, and only the ON light level is reduced. Therefore, not only the brightness of the projection display device is reduced but also the ON light level / OFF light level. This causes a decrease in contrast of the projected display device.
[0015]
Also, in an optical system using a PBS, as the angle of incidence on the PBS increases, the difference between the polarization direction of the light beam incident on the light valve and the polarization direction of the light beam emitted from the light valve increases, so that the OFF light level is increased. In this case, light leakage increases and the contrast decreases. FIG. 4 is a schematic diagram showing a relationship between an incident light beam and a reflected light beam with respect to the PBS. Here, for convenience of description, the light valve is replaced with a plane mirror. In FIG. 4, reference numeral 21 denotes a reflection surface of the PBS 109, which reflects the S-polarized light component and makes the P-polarized light component go straight. The incident optical axis 22 to the PBS 109 is the Y axis, the reflected optical axis 23 is the Z axis, and the direction orthogonal to the Y axis and the Z axis is the X axis.
[0016]
As shown in FIG. 4, when the light ray 24 incident on the PBS 109 is in the XY plane and the incident direction is not parallel to the Y axis, both the light ray 25 incident on the plane mirror 29 and its reflected light ray 26 are in the XZ plane. And the direction which bisects the angle between the incident light beam 25 to the plane mirror 29 and the reflected light beam 26 from the plane mirror 29 is parallel to the Z axis. However, the direction of the S-polarized light with respect to the incident light beam 25 to the plane mirror 29 and the reflected light beam 26 from the plane mirror 29 is not parallel to the XZ plane. That is, the direction of the S-polarized light with respect to the X-axis is such that the incident light beam 25 rotates counterclockwise and the reflected light beam 26 rotates clockwise by the same amount. The S-polarized light with respect to the reflected light beam 26 becomes linearly polarized light in the polarization direction 28, but since the plane mirror 29 does not change the polarization state before and after reflection, the S-polarized light in the reflected light beam 26 becomes linearly polarized light in the polarization direction 29 and reflected by the PBS 109. It does not coincide with the direction 28 of the s-polarized light for the ray 26. For this reason, a part of the reflected light beam 26 travels straight through the PBS 109, causing a decrease in contrast. This phenomenon becomes more remarkable as the angle between the incident light beam 24 and the incident optical axis 22 on the PBS 109 increases.
[0017]
On the other hand, in the case of a projection display device using a transmission type light valve, an ultra-high pressure mercury lamp or a metal halide lamp having excellent luminous efficiency is used as a light source lamp. Since these lamps have a lower ratio of red light than blue light and green light, a method of electrically lowering the light use efficiency of blue light and green light to secure color reproducibility has been adopted. As in the case where the reflection type light valve is used, the brightness and contrast of the projection type display device are reduced.
[0018]
In order to solve such a problem, a method of optically limiting an incident angle of a predetermined light flux among red light, green light, and blue light to the light valve can be considered. However, in the method described in Patent Literature 1, the light blocking unit is provided near the light valve in order to limit the incident angle of the light beam to the projection screen, but when the light blocking unit is arranged near the light valve. Since the shadow of the light shielding means itself enters the light valve, unevenness occurs in the brightness of the color light whose incident angle is limited. In the methods described in Patent Documents 2 and 3, vignetting is used to attenuate a part of the incident light beam asymmetrically with respect to the optical axis in accordance with the viewing angle characteristics of the liquid crystal panel used for the light valve. Image unevenness is inevitable.
[0019]
The present invention has been made in view of the above circumstances, and has as its object to provide a high-quality projection-type display device that is high in contrast and free from illuminance unevenness and color unevenness.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the present invention comprises an illumination optical system, and at least one light valve for modulating light from a light source guided through the illumination optical system to generate image light, wherein the image light In the projection display device that projects light, the illumination optical system spatially or temporally resolves light from a light source into three color lights having different wavelength ranges, and an integrator optical system that uniformly illuminates the light valve. A light decomposing means; and a light shielding means for restricting an incident light beam angle to the light valve for one or two of the color lights decomposed by the light decomposing means, and a position conjugate with the light source by the integrator optical system. And a position conjugate with the light valve is present in the illumination optical system, and the light shielding means is provided at a position conjugate with the light source and a light valve position adjacent to the position conjugate with the light source. Alternatively, it is disposed on a position conjugate with the light source with respect to a midpoint between the position conjugate with the light valve and is symmetrical with respect to two axes passing through the optical axis center and forming a plane perpendicular to the optical axis and orthogonal to each other. It is characterized in that the incident light beam is shielded.
[0021]
According to this configuration, the ON light level and the OFF light level can be simultaneously reduced according to the light having the lowest utilization efficiency among the red light, the green light, and the blue light, and the light utilization of the red light, the green light, and the blue light can be achieved. By adjusting the efficiency to an appropriate ratio, it is possible to provide a projection type display device with high contrast and high image quality without reducing the brightness while ensuring the balance of each color. Further, by adjusting the balance of each color to an appropriate ratio, a desired color temperature can be set. In addition, since the light shielding means is arranged at a predetermined position in the illumination optical system, when an image is projected on the screen, the light amount balance of red light, green light, and blue light is secured at the center and the periphery of the screen, and the screen is screened. Color unevenness during projection is suppressed. Further, since the incident light beam is restricted to be symmetrical with respect to two axes which are orthogonal to the optical axis and form a plane perpendicular to the optical axis, color unevenness due to vignetting can be prevented.
[0022]
Also, in an optical system using a PBS, the angle of the light beam incident on the PBS can be limited, so that in addition to reducing the amount of light incident on the light valve, the polarization plane of the light beam incident on the light valve and the light beam emitted from the light valve can be reduced. The effect of reducing light leakage at the OFF light level generated due to the difference can be obtained, and a projection display device with higher contrast can be provided. It is also known that the transmittance of the P-polarized light component decreases as the angle of the incident light with respect to the reflection film of the PBS increases, and it is preferable to reduce the angle of the incident light beam from the viewpoint of the reflection film design of the PBS.
[0023]
The present invention further includes an illumination optical system, and at least one light valve that modulates light from a light source guided through the illumination optical system to generate image light, and a projection type that projects the image light. In the display device, the illumination optical system is an integrator optical system that uniformly illuminates the light valve, and a light decomposing unit that spatially or temporally decomposes light from a light source into three color lights having different wavelength ranges. Light-blocking means for restricting an incident light beam angle to the light valve with respect to one or two colors of the color light decomposed by the light decomposing means, wherein the light-shielding means varies an incident light beam angle to the light valve; It can be controlled.
[0024]
According to this configuration, the angle of incidence of the light beam on the light valve can be variably controlled depending on the projection state, use state, application, and the like of the projection display device, so that it is easy to adjust the balance and contrast of each color.
[0025]
Further, according to the present invention, in the projection display device having the above-described configuration, an incident light beam angle incident on the light valve is different for each of three color lights having different wavelength ranges.
[0026]
According to this configuration, even when the light use efficiency is different for each of red light, green light, and blue light, the ON light level and the OFF light level can be simultaneously reduced according to the lowest light of the three colors. By equalizing the light use efficiency of light, green light, and blue light, the balance of each color can be secured. In particular, when PBS is used for the optical system, red light is most often limited in order to prevent the image quality from dropping yellowish on the projection screen, and when a high-pressure mercury lamp or metal halide lamp with a low ratio of red light is used as the light source, By limiting blue light most, high-contrast display can be realized while ensuring color reproducibility.
[0027]
Further, according to the present invention, in the projection display device having the above-described configuration, among the three color optical paths having different wavelength ranges decomposed by the photodecomposition means, the three color optical paths are arranged in optical paths having different optical path lengths as compared with other color lights. The illumination optical system includes, in order from the side, a relay optical system including at least one first lens, a second relay lens, and a third relay lens each including at least one lens. It is provided between the middle point of the second relay lens and the middle point of the second relay lens and the third relay lens.
[0028]
According to this configuration, even when light is incident on the light valve via the relay optical system, it is possible to provide a projection type display device that maintains a balance of each color and has high contrast and high image quality without reducing brightness. Can be. Further, by disposing the light shielding means at a predetermined position in the relay optical system, it is possible to prevent color unevenness at the time of screen projection.
[0029]
Further, according to the present invention, in the projection display device having the above-described configuration, the light shielding unit has a dichroic characteristic of transmitting all visible light in a central portion and reflecting light in a part of a wavelength band in a peripheral portion. And
[0030]
According to this configuration, it is possible to easily and reliably reduce only excess components among red light, green light, and blue light of the illumination light from the light source by selecting the coating characteristics of the dichroic coat and adjusting the coating area.
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 6 is a schematic diagram showing the projection display device of the first embodiment. The projection display device using the conventional reflection type light valve shown in FIG. 1 having a color balance as shown in FIG. It was done. The rough configuration and some of the components of the projection display device are common to those in FIG. For convenience of description, the same parts as those in FIG. 1 are denoted by the same reference numerals.
[0032]
In FIG. 6, reference numeral 1 denotes a light blocking unit that limits an incident angle of a predetermined color of a light beam emitted from the light source 101 to the light valve, and is disposed between the second lens array 103 and the superimposing lens 104 with respect to the optical axis. Are arranged vertically. In the present embodiment, by limiting the incident angles of the green light and the red light incident on the light valves 113 and 114, the light use efficiency of the red light, the green light, and the blue light is made uniform, and the balance of each color is secured. High-contrast display without lowering the brightness.
[0033]
As shown in FIG. 7, a color filter in which an anti-reflection coating (hereinafter, referred to as an AR coating) 3 is coated in a circular shape on the center of a flat plate 2 made of glass is used for the light shielding means 1 used in the present embodiment. I have. A dichroic coat 4 that transmits only light of a specific color is coated on the periphery of the antireflection coat 3, and in the present embodiment, a dichroic coat that transmits only blue light is used. FIG. 8 shows the coating characteristics of the AR coat 3 and the dichroic coat 4 used in the present embodiment. The AR coat 3 has nearly 100% transmittance for each wavelength from the blue region to the red region (FIG. 8A). On the other hand, the dichroic coat 4 shows a transmittance close to 100% in the blue region, but the transmittance sharply decreases on the longer wavelength side than the blue region, and the transmittance becomes almost 0% in the green and red regions. (FIG. 8B). In this embodiment, the dichroic coat 4 transmits blue light but does not transmit green light and red light. However, the wavelength is selected in accordance with the color deficient in the projection display device and its light amount. The coat to be transmitted can be arbitrarily selected.
[0034]
The shape of the part coated with the AR coat 3 is not limited to a circle, but may be an ellipse as shown in FIG. 16A, a cat-eye shape as shown in FIG. 16B, or a cat-eye shape as shown in FIG. Other shapes symmetrical about two axes perpendicular to the optical axis, such as a rectangle as shown in FIG. When the characteristics of the polarization plane of the PBS are different in the vertical direction and the horizontal direction, for example, as shown in FIG. 4, the phenomenon of the decrease in contrast due to the direction of the light beam incident on the PBS becomes remarkable due to the shift of the incident light beam in the Y-axis direction. In such a case, in order to limit the incident light beam in the Y-axis direction, it is preferable that the shape be an ellipse or a cat's eye shape elongated in the Z-axis direction.
[0035]
FIG. 9 shows a schematic optical path diagram after the light shielding means in the present embodiment. Mirrors, superimposed lenses, and the like are omitted for convenience of explanation. Although the field lens, the PBS, and the light valve are provided for each color, only one color is shown here. The luminous flux transmitted through the light shielding unit 1 passes through the field lenses 117, 118, 119 and the PBSs 109, 110, 111 and enters the light valves 112, 113, 114. At this time, the blue light passes through the entire area of the light blocking means 1 and reaches the light valve 112, whereas the green light and the red light do not pass through the dichroic coat 4, so that the center circle coated with the AR coat 3 is formed. The light only passes through the light valves 113 and 114 to reach the light valves 113 and 114. Accordingly, the light flux D of all colors passes through the central circular portion, and only the blue light E passes through the peripheral portion. The green light and the red light incident on the light valves 113 and 114 pass through the light valve 112. Since the incident angle is limited as compared with the incident blue light, the light use efficiency of each color light incident on the light valves 112, 113, 114 becomes uniform.
[0036]
FIG. 10 shows the relationship between color correction by reducing the luminous flux angle and brightness / contrast according to the present embodiment. In the present embodiment, in order to optically reduce the amount of incident light using a coat having wavelength selectivity, unlike the case of FIG. 3 in which color correction is performed by an electric control unit, the ON light levels of red light and green light and The OFF light levels are both k × A and k × C (k <1) due to the correction, and are about the same as the blue light (FIG. 10B). As a result, the contrast after correction is k × A / k × C (k <1) = A / C for the red light and the green light, and is maintained at the same level as the contrast A / C before the correction. It is possible to prevent a decrease in contrast of the projection display device represented by the light level / OFF light level. In this embodiment, high contrast is realized by equalizing the balance of red light, green light, and blue light by color correction. However, by adjusting the color balance of each color to an appropriate ratio, a desired ratio can be obtained. Can be set.
[0037]
Next, the effect of the present embodiment in the optical system using the PBS by reducing the light beam angle will be described. FIG. 11 shows the effect of the present embodiment on the PBS by reducing the light beam angle. In an optical system using a PBS, as the angle of incidence on the PBS increases, the difference between the polarization direction of the light beam incident on the light valve and the polarization direction of the light beam emitted from the light valve increases. In this embodiment, in addition to the effect of reducing the amount of incident light (× k) shown in FIG. 10, the OFF light level due to the restriction of the incident angle to the PBS increases the light leakage, which causes a decrease in contrast. Light leakage prevention effect (× m). Therefore, while the ON light levels of the red light and the green light both become k × A (k <1) by correction, the OFF light levels both become kk × m × C (k <1, m <1) by correction. (FIG. 11B). As a result, the contrast after correction for red light and green light is k × A / k × m × C (k <1, m <1) = A / m × C (m <1), and the contrast before correction is obtained. Since it is higher than A / C, higher contrast can be realized than before color correction.
[0038]
Next, another embodiment of the light shielding means used in the present embodiment will be described. FIG. 12 is a schematic configuration diagram showing the light shielding means in the present embodiment, in which the light shielding means 1 can be variably controlled. In FIG. 12, the light shielding unit 1 is composed of two glass flat plates 2 coated with a dichroic coat 4 that transmits only light of a specific color, and covers the upper end and the lower end of the second lens array 103. Are located. Further, each flat plate 2 is configured to be slidable along the lens surface of the second lens array 103, and the incident angle of the light beam can be variably controlled according to the projection state, use situation, use, etc. of the projection display device. The adjustment of the balance and the contrast becomes easy. In this example, the light-shielding means 1 is arranged so as to cover the upper end and the lower end of the second lens array 103 and can be variably controlled. Is also good. Further, the light shielding means 1 may be structured like a diaphragm of a camera so that the size of the light shielding portion can be variably controlled uniformly with respect to the center of the optical axis.
[0039]
In the present embodiment, the light shielding means 1 is arranged near the second lens array 103, but may be arranged at another position in the illumination optical system from the light source 101 to each of the light valves 112, 113, 114. As shown in FIG. 13, they are arranged between a midpoint F between the first lens array 102 and the second lens array 103 and a midpoint H between each of the light valves 112, 113, 114 and the second lens array 103. Is preferred. Since the second lens array 103 is located at a position conjugate to the light source 101 and the first lens array 102 is located at a position conjugate to each of the light valves 112, 113, and 114, the light shielding means 1 is located at a position conjugate to the light source. Must be located at a position conjugate to the light source from the midpoint of the position conjugate to the light valve and at a position conjugate to the light source at a position conjugate to the light source and the midpoint of the light valve. It becomes. When the light source is arranged in the above range, the shadow of the light shielding means 1 itself is not reflected on the light valve, and the blue, green, and red light amount balances are secured between the central portion and the peripheral portion of the screen. Color unevenness can be suppressed. It is also possible to join the light shielding means 1 to an existing optical component, or to use the same as the optical component itself such as the second lens array. For example, when the AR coat 3 and the dichroic coat 4 are coated on one of the surfaces of the second lens array, the AR coat 3 and the dichroic coat 4 may be used.
[0040]
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 14 is a schematic diagram showing the configuration of a projection display device according to a second embodiment, which is an improvement of the projection display device using the conventional transmission light valve shown in FIG. The configuration and components of the projection display device are common to those in FIG. Note that, for convenience of description, the same portions as those in FIG. 5 are denoted by the same reference numerals.
[0041]
The light shielding means 1 of the present embodiment is also arranged between the second lens array 103 and the superimposed lens 104, which are conjugate with the light source 101. The configuration of the light shielding means 1 is the same as that of the first embodiment. However, in this embodiment, since the insufficient light is red light, the dichroic coat 4 transmits the red light in FIG. Those that do not transmit light are used. Further, similarly to the first embodiment, it is possible to arbitrarily select a coat that selectively transmits a wavelength according to a color that is insufficient in the projection display device and its light amount.
[0042]
Further, similarly to the first embodiment, the light shielding means 1 can be variably controlled by a configuration as shown in FIG. 12, and the light shielding means 1 can be joined to an existing optical component, or a second lens array or the like can be used. Can also be used as the optical component itself. Further, the light shielding means 1 is arranged near the second lens array 103, but as shown in FIG. 13, the midpoint F between the first lens array 102 and the second lens array 103, and each light valve 112, 113, 114 Needless to say, it can be arranged between the first lens array 103 and the middle point H of the second lens array 103.
[0043]
In the present embodiment, since the PBS is not used in the optical system, the effect on the PBS by reducing the luminous flux angle does not occur. However, by restricting the luminous flux angle to the light valve, the amount of incident light is optically reduced so that electrical Compared with the case where the color correction is performed by the control means, the contrast after the color correction is maintained at substantially the same level as the contrast before the color correction, and the contrast of the projection display device represented by the ON light level / OFF light level due to the color correction is reduced. Can be prevented.
[0044]
Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 15 is a schematic diagram showing the configuration of a projection display device according to a third embodiment, which is an improvement of the projection display device using the conventional reflection type light valve shown in FIG. PBSs 120, 121, and 122 are added to each of the optical paths of light, green light, and red light. Since the configuration and components of the projection display device are common to those in FIG. 2, the description is omitted. For convenience of description, the same parts as those in FIG. 2 of the conventional example are denoted by the same reference numerals.
[0045]
In the present embodiment, in the projection type display device using the conventional reflection type light valve shown in FIG. 2, the light shielding means 5 is disposed between the dichroic mirror 105b for reflecting green light and red light and the reflection mirror 108. I have. As shown in FIG. 15, the light shielding means 5 is such that a passage hole 5a is formed in, for example, a metal plate or the like, and a portion other than the passage hole 5a is a light shielding portion 5b. The incident angles of the green light and the red light reflected by the dichroic mirror 105b are reduced by passing through the passage holes 5a of the light shielding means 5. In the present embodiment, the shape of the passage hole 5a is an octagon, but an oval shape as shown in FIG. 16 (a), a cat-eye shape as shown in FIG. 16 (b), and a cat-eye shape as shown in FIG. 16 (c). Other shapes, such as a rectangle as shown, can also be used. The illumination light from the light source 101 has a symmetric spread with respect to the optical axis, whereas the projected image usually has a different aspect ratio, so that the panel surface of the light valve also has an aspect ratio. Therefore, especially when the light shielding means 5 is arranged near the light valve, it is more preferable to make the shape according to the image such as an elliptical shape or a cat's eye shape because the image does not become uneven. Also, the size of the passage hole 5a can be arbitrarily selected according to the degree of reducing the amount of incident light. For example, the size of the passage hole 5a can be variably controlled by, for example, making the light shielding means 5 like a camera aperture. It can also be.
[0046]
FIG. 17 shows a schematic optical path diagram after the light shielding means in the present embodiment. Mirrors, superimposed lenses, and the like are omitted for convenience of explanation. The field lens, the PBS, and the light valve are provided for each color. Here, green light and red light are shown for only one color. In the present embodiment, since the light blocking means 5 is not provided in the optical path of the blue light, all the blue light reflected by the dichroic mirror 105a reaches the light valve 112 (FIG. 17A). On the other hand, only the green light and the red light that have passed through the passage hole 2a of the light blocking means 5 reach the light valves 113 and 114 (FIG. 17B). Since the angles of incidence of the green light and red light incident on the light valves 113 and 114 are limited as compared with the blue light incident on the light valve 112, the light use efficiency of each color light incident on the light valves 112, 113 and 114 is equal. become. As a result, even when a plurality of PBSs are used for each optical path, it is possible to prevent a decrease in image quality due to the yellowishness of the projection screen, and to secure a high-contrast and high-quality projected image.
[0047]
Next, a case where the color balance of the projection display apparatus before color correction increases in the order of blue light, green light, and red light as shown in FIG. 19 will be described. FIG. 18 is a schematic diagram showing the configuration of a projection display device according to a fourth embodiment of the present invention, which is a further improvement of the projection display device using the reflection type light valve shown in FIG. The configuration and components of the projection display device are the same as those in FIG.
[0048]
In the present embodiment, in addition to the wavelength-selective first light-blocking means 1 disposed between the second lens array 103 and the superimposing lens 104, the light-blocking means 5 of the third embodiment is used as a second light-blocking means. It is arranged between the dichroic mirror 105b and the reflection mirror. The light incident angles of the lights of each color are corrected in two stages by the light shielding means 1 and 5, and the red light, green light and blue light are equally used by blocking the red light most and then the green light. To ensure the balance of each color.
[0049]
FIG. 20 shows the characteristics and shape of the light shielding means used in this embodiment. As in the first and second embodiments, a color filter is used for the first light shielding means 1, and an AR coat 3 is coated in a circular shape on a central portion of a glass flat plate 2. The peripheral portion is coated with a dichroic coat 4 that transmits only light of a specific color (FIG. 20B). In the present embodiment, a material that transmits only blue light and green light is used, and the dichroic coat 4 shows a transmittance close to 100% in the blue region and the green region, but rapidly transmits on the longer wavelength side than the green region. The transmittance is reduced, and the transmittance is almost 0% in the red region (FIG. 20A). The second light-shielding means 5 is, as in the third embodiment, provided with a through-hole 5a in a metal plate or the like and a portion other than the through-hole 5a as a light-shielding portion 5b. The hole 5a is formed in a size and a shape such that light passing through the circular portion of the first light shielding means 1 coated with the AR coat 3 is not affected (FIG. 20C).
[0050]
FIG. 21 is a schematic optical path diagram after the light shielding means in the present embodiment. Mirrors, superimposed lenses, and the like are omitted for convenience of explanation. The field lens, the PBS, and the light valve are provided for each color. Here, green light and red light are shown for only one color. In this case, the blue light passes through the entire area of the first light blocking means 1, and further, since the second light blocking means 5 is not provided in the optical path of the blue light, all of the blue light passing through the second lens array 103 is emitted. The light reaches the light valve 112 (FIG. 21A). On the other hand, the green light and the red light reach the light valves 113 and 114 by passing through the passage holes 5 a of the second light shielding means 5, but the red light passes through the dichroic coat 4 when passing through the first light shielding means 1. Therefore, the light reaches the light valve 114 without being affected by the second light blocking means 5. On the other hand, like the blue light, the green light passes through the entire region without being restricted by the first light shielding means 1, so that the incident angle is reduced by the second light shielding means 5 and reaches the light valve 113 ( FIG. 21 (b). As a result, the incident angle is restricted in the order of red light and green light, and blue light reaches the light valve without being restricted by the incident angle. Efficiency becomes equal.
[0051]
The first light shielding means 1 can arbitrarily select the size of the coating portion, the type of the coating material that selectively transmits the wavelength, and the like, based on the balance of the red light, green light, and blue light before color correction. Similarly, the shape and size of the passage hole 5a of the second light shielding means 5 can be arbitrarily selected without departing from the object of the present invention. That is, by appropriately combining these light-shielding means 1 and 5, it is possible to achieve an optimal color balance.
[0052]
According to the present embodiment, similarly to the first embodiment, the contrast after color correction is improved by optically reducing the amount of light incident on the light valve, as compared with the case where color correction is performed by the electrical control means. Maintain the same level as the contrast before correction. In addition, since the PBS is used for the optical system, an effect on the PBS by reducing the luminous flux angle is also expected, and the contrast of the projection display device represented by ON light level / OFF light level by color correction can be improved. it can.
[0053]
In the fourth embodiment, the second light blocking means 5 is disposed between the dichroic mirror 105b and the reflection mirror 108. However, the position of the second light blocking means 5 is not limited to this, and the light source may be a light source. It can be arranged at another position in the illumination optical system from 101 to each light valve 112, 113, 114. However, when the light shielding means 5 is configured by a light shielding plate provided with a light passage hole 5a and a light shielding part 5b as in the present embodiment, the angles of all the light beams passing through the light shielding means 5 are limited. It cannot be arranged before the dichroic mirror group 105. By arranging the red light, the green light, and the blue light at a stage subsequent to the light decomposing unit that separates at least one of the light beams, the balance of each color can be adjusted.
[0054]
FIG. 22 is a schematic configuration diagram illustrating a projection display device according to a fifth embodiment of the present invention. In the present embodiment, the second light shielding means 5 is arranged downstream of the reflection mirror 108. The other configuration of the projection display device is common to that of the fourth embodiment, and thus the description is omitted. Further, here, the first light shielding means 1 is arranged near the second lens array 103 similarly to the fourth embodiment, but the arrangement of the first light shielding means 1 is appropriately set within the scope of the present invention. Can be selected.
[0055]
Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 23 is a schematic diagram showing the configuration of a projection display device according to a sixth embodiment, which is an improvement of the projection display device using the conventional transmission light valve shown in FIG. The configuration and components of the projection display device are common to those in FIG. In the present embodiment, it is assumed that blue light is guided to the light valve via the relay optical system, and the color balance of the projection display device before color correction is changed to red light, green light as shown in FIG. , Blue light will be described in this order.
[0056]
In the present embodiment, in addition to the configuration of the second embodiment in which the first light-shielding means 1 is provided by wavelength selection, the second light-shielding means 5 in which a light-shielding plate is provided with a passage hole 5a is used in combination with the fourth embodiment. Similarly, the light use efficiency of each color light is equalized. In FIG. 23, since the optical path of the blue light has a longer optical path length than the red light and the green light, the light use efficiency of the blue light is prevented from being reduced, and the same illumination state as the red light and the green light is used. The light enters the light valve 109 via a relay lens optical system 128 in which a first relay lens 125, a second relay lens 126, and a third relay lens 127 are combined. The first light shielding means 1 is disposed between the second lens array 103 and the superimposed lens 104 similarly to the second embodiment, and the second light shielding means 5 is located at a position conjugate with the second lens array 103 in blue. It is arranged near the second relay lens 126 in the relay optical system 128 provided on the optical path of light.
[0057]
FIG. 25 shows the characteristics of the first light shielding means by wavelength selection used in the present embodiment. In the present embodiment, a material that transmits only red light is used, and the dichroic coat 4 shows a transmittance close to 100% in the red region, but the transmittance decreases sharply on the shorter wavelength side than the red region, and the green color In the region and the blue region, the transmittance is almost 0%. As shown in FIG. 22, the second light-shielding means 5 has a circular through-hole 5a formed in a metal plate or the like, as in the third embodiment, and a portion other than the through-hole 5a is a light-shielding portion 5b. However, in the present embodiment, the passage hole 5a is configured to have a size that further reduces the light that has passed through the circular portion of the first light shielding unit 1 on which the AR coat 3 is coated.
[0058]
FIG. 26 is a schematic optical path diagram after the light shielding means in the present embodiment. Mirrors, superimposed lenses, and the like are omitted for convenience of explanation. The field lens and the light valve are provided for each color. Here, green light and red light are shown for only one color. In FIG. 24, the red light reaches the light valve 114 after passing through the entire area of the first light blocking means 1, but the green light passes through the light blocking means 1 when the incident angle is reduced by the dichroic coat 4 to reduce the AR. The light passes through only the central circular portion coated with the coat 3 and reaches the light valve 113 (FIG. 26A). On the other hand, like the green light, the blue light passes through only the central circular portion of the first light-shielding means 1 coated with the AR coat 3 and is guided into the relay optical system 128. The second light blocking means 5 is provided near the second relay lens 126 in the relay optical system 128, and the blue light passes through the passage hole 5 a of the second light blocking means 5, so that the blue light is more than the green light. The incident angle is further reduced and reaches the light valve 112 (FIG. 26B). Thereby, contrary to the fourth embodiment, the incident angle of the blue light is most frequently restricted, then the green light is restricted, and the red light reaches the light valve without any restriction. The light use efficiency of each color light incident on 113 and 114 becomes uniform.
[0059]
Also in the present embodiment, similarly to the fourth embodiment, the shape and size of the coating portion of the first light shielding means 1, the type of the coating material that selectively transmits the wavelength, and the like can be arbitrarily selected. Similarly, the shape and size of the passage hole 5a of the second light shielding means 5 can be arbitrarily selected. In the present embodiment, the second light blocking means 5 is configured to provide the passage hole 5a in the metal plate to limit the incident angle. However, without providing the second light blocking means 5, the second relay lens 126 The incident angle can also be limited by reducing the lens diameter. Further, these light shielding means 1 and 5 may be configured so that the incident angle of the light beam can be variably controlled depending on the projection state, use situation, use, etc. of the projection display device.
[0060]
Further, the first light shielding means 1 and the second light shielding means 5 can be arranged at other positions in the illumination optical system. FIG. 27 is a schematic diagram showing the position where the light shielding means can be arranged in the present embodiment. As shown in FIG. 27, in the present embodiment, in addition to the second lens array 103, the second relay lens 126 is also at a position conjugate with the light source 101, and the first relay lens 125 in addition to the first lens array 102 is also a light. It is at a position conjugate with the valve 112. Therefore, the first light-shielding unit 1 is connected to the second lens array 103 at a position conjugate with the light source 101, and the first lens array 102 and the first lens array 102 at positions conjugate with the light valve 112 adjacent to the second lens array 103. The second light blocking means 5 is disposed between the middle points I and J with the relay lens 125, and the second light blocking means 5 is disposed at a position conjugate with the light source 101 and the light valve 112 adjacent to the second relay lens 126. It is preferable to arrange between the middle point K between the first relay lens 125 and the middle point L between the second relay lens 126 and the light valve 112 at a position conjugate with the first relay lens 125. Here, since the third relay lens 127 is located near the light valve 112, the second light blocking means 5 is located at the midpoint between the first relay lens 125 and the second relay lens 126, and between the second relay lens 126 and the third relay lens 126. It is arranged between the relay lens 127 and the middle point. By arranging the first light-shielding means 1 and the second light-shielding means 5 at positions substantially conjugate to the light source 101 in this manner, it is possible to prevent color unevenness at the time of projecting a screen due to shadows of the light-shielding means 1 and 5 themselves. it can.
[0061]
In the present embodiment, the PBS is not used in the optical system as in the second embodiment, so that the effect on the PBS by reducing the luminous flux angle does not occur. However, by optically reducing the amount of light incident on the light valve, electric power is reduced. As compared with the case where the color correction is performed by the dynamic control means, it is possible to prevent a decrease in the contrast of the projection display device represented by the ON light level / OFF light level due to the color correction.
[0062]
Next, an example in which the present invention is applied to a single-panel light valve projection display device will be described. FIG. 28 is a schematic configuration diagram showing a projection display device according to the seventh embodiment of the present invention. In the present embodiment, a color wheel is used as a light decomposing unit instead of the dichroic mirror. For the sake of convenience, the same parts as those of the conventional example are denoted by the same reference numerals.
[0063]
In FIG. 28, light emitted from a light source 101 is focused by a condenser lens 5 near a color wheel 6. The color wheel 6 has a color filter 7 near the focal point of the condenser lens 5 that passes each color component of red light, green light, and blue light at a position equidistant from the rotation axis 8. The color of transmitted light is sequentially switched over time by rotating at high speed around the center 8. The light transmitted through the color wheel 6 is collimated by the collimator lens 9 with respect to the optical axis. In this embodiment, the condenser lens 5 is used to focus on the vicinity of the color wheel 6, but, for example, the light source 101 is an elliptical reflector having a first focal point and a second focal point, and a color near the second focal point. The configuration may be such that the wheel 6 is disposed so that light emitted from near the first focus is focused near the color wheel 6.
[0064]
The light collimated by the collimator lens 9 is made uniform by the first lens array 102 and the second lens array 103. In the present embodiment, the reflection mirrors 10 and 11 are arranged between the collimator lens 9 and the first lens array 102 and between the first lens array 102 and the second lens array 103 to change the optical path by 180 °. are doing. The light emitted from each cell of the second lens array passes through the superimposing lens 104, the optical path is bent by 90 ° by the reflection mirror 12, passes through the field lens 13, and enters the PBS 14. The field lens 13 is provided to convert the light beam from the light source 101 into a telecentric light beam and to reduce an error in a projected image.
[0065]
The light beam whose traveling direction is bent by 90 ° by the PBS 14 enters the light valve 15. At this time, a polarization component unnecessary for illumination of the light valve 15 is removed by the PBS 14. The light flux modulated by the light valve 15 is incident on the PBS 14 again, and after a polarization component unnecessary for screen projection is removed, the light flux is projected on a screen (not shown) by the projection lens 116.
[0066]
In the present embodiment, the light shielding unit 1 is disposed between the second lens array 103 and the superimposed lens 104 which are conjugate to the light source 101. Accordingly, the incident angle of light of a predetermined color incident on the light valve 15 is limited, the light use efficiency of red light, green light, and blue light is made uniform, the balance of each color is secured, and the brightness is not reduced. Thus, a high-contrast display is realized. The configuration of the light shielding means 1, coat characteristics, disposable positions, and the like are the same as those in the first embodiment, and thus description thereof is omitted. In this embodiment, the position of the color wheel 6 is also changed in addition to the second lens array 103. , It is also possible to arrange the light blocking means 1 between the color wheel 6 and the midpoint between the condenser lens 5 and the collimator lens 9 conjugate with the light valve 15. Further, the light shielding means 1 may be configured so that the incident angle of the light beam can be variably controlled depending on the projection state, use situation, use, and the like of the projection display device.
[0067]
According to the present embodiment, similarly to the first embodiment, the contrast after color correction is improved by optically reducing the amount of light incident on the light valve, as compared with the case where color correction is performed by the electrical control means. Maintain the same level as the contrast before correction. In addition, since the PBS is used for the optical system, an effect on the PBS by reducing the luminous flux angle is also expected, and the contrast of the projection display device represented by ON light level / OFF light level by color correction can be improved. it can. Further, since the light shielding means 1 is arranged near the second lens array 103 which is conjugate to the light source 101, the shadow of the light shielding means 1 itself does not enter the light valve, thereby suppressing unevenness in brightness. it can.
[0068]
FIG. 29 is a schematic configuration diagram showing a projection display device according to the eighth embodiment of the present invention. In the present embodiment, the light valve 16 is configured to have pixels corresponding to red light, green light, and blue light, and further uses a dichroic mirror group instead of the color wheel of the seventh embodiment to change the illumination light to red, green, and , Has been separated into blue colors. For the sake of convenience, the same parts as those of the conventional example are denoted by the same reference numerals.
[0069]
In FIG. 29, a light beam emitted from a light source 101 is made uniform by a first lens array 102 and a second lens array, passes through a superimposing lens 104, and is emitted by a group of dichroic mirrors 17 and 18 as a light decomposing means. , Green light and blue light. The luminous flux separated into each color is converted into a telecentric luminous flux by a field lens 19, and then enters a light valve 16 mounted on a prism 20. A hologram lens (not shown) is provided for each pixel on the light valve 16, and each light beam of red, green, and blue is applied to a pixel corresponding to each color formed on the light valve 16 by the hologram lens. You. The luminous flux of each color is modulated by driving the electrode of the pixel corresponding to each color of the light valve 16 and projected on a screen (not shown) via the projection lens 116.
[0070]
In the present embodiment, as in the seventh embodiment, the light shielding means 1 is disposed between the second lens array 103 and the superposed lens 104 conjugate to the light source 101. This makes it possible to limit the incident angle of light of a predetermined color to the light valve 16, equalize the light use efficiency of red light, green light, and blue light, secure the balance of each color, and increase the brightness. A high-contrast display is realized without lowering. Furthermore, the shadow of the light shielding means 1 itself does not enter the light valve, and thus unevenness in brightness can be suppressed. Note that the configuration of the light shielding means 1, the coating characteristics, the disposable position, and the like are the same as those in the first embodiment, and thus description thereof is omitted. Further, as shown in FIG. 12, the light shielding means 1 may be configured so that the incident angle of the light beam can be variably controlled depending on the projection state, use situation, application, etc. of the projection display device.
[0071]
In addition, when the light shielding unit 1 is not used, the luminous flux is spread, so that the luminous flux of each color is not accurately irradiated to the pixel corresponding to the desired color by the hologram lens, and color mixing may occur. In the projection display device of the present embodiment including the light shielding unit 1, the angle of incidence of the light beam of the desired color on the light valve 16 can be reduced, so that the color mixture of the desired color can be performed while adjusting the brightness and the contrast. It is possible to prevent. In this case, since the pixels corresponding to the respective colors are rectangular, it is possible to effectively prevent color mixing by making the shape of the AR coat portion of the light shielding means 1 an elliptical shape or a cat's eye shape as shown in FIG. Can be.
[0072]
In each of the above embodiments, an integrator optical system using a lens array is used in order to uniformly and efficiently illuminate the light valve. However, other systems, such as an integrator using a rod integrator, are used. An optical system may be used. In an integrator optical system using a rod integrator, a position conjugate with the light source and a position conjugate with the light valve can be defined. As in the case of using a lens array, in an illumination optical system with an integrator optical system using a rod integrator. Also, the light shielding means of the present invention can be effectively applied. In the above embodiment, the liquid crystal panel is used as the light valve. However, the configuration of the light valve is not limited to this. For example, a DMD (Digital Micromirror Device) manufactured by Texas Instruments of the United States can be used. Other elements other than the above may be used.
[0073]
【The invention's effect】
According to the present invention, a projection type that includes an illumination optical system and at least one light valve that modulates light from a light source guided through the illumination optical system to generate image light, and projects the image light In the display device, the illumination optical system is an integrator optical system that uniformly illuminates the light valve, and a light decomposing unit that spatially or temporally decomposes light from a light source into three color lights having different wavelength ranges. Light-blocking means for restricting an incident light beam angle to the light valve for one or two colors of the color light decomposed by the photodecomposition means, and a position conjugate with a light source by the integrator optical system, and a light valve. A conjugate position exists in the illumination optical system, and the light shielding unit includes a position conjugate with the light source and a light valve position or a light valve adjacent to the position conjugate with the light source. The luminous flux is arranged symmetrically with respect to two axes which are arranged on a position conjugate with the light source with respect to the midpoint of the conjugate position and which are orthogonal to each other through the center of the optical axis and form a plane perpendicular to the optical axis. By shielding the light, a balance between the colors can be ensured, and a high-contrast, high-quality projection display device can be provided without reducing the brightness. In addition, when an image is projected on a screen, the light amount balance of red light, green light, and blue light is secured between the central part and the peripheral part of the screen, so that color unevenness at the time of projecting the screen is suppressed, and the color due to vignetting is further reduced. Unevenness can also be prevented.
[0074]
In addition, when a PBS is used for the optical system, the angle of the light beam incident on the PBS can be limited at the same time, so that in addition to the reduction of the amount of light incident on the light valve, the polarization plane of the light beam incident on the light valve and the light beam emitted from the light valve are reduced. The effect of reducing light leakage at the OFF light level generated due to the difference between the two can be obtained, and a projection type display device with higher contrast can be provided. Further, in the case where the light valve has a configuration having pixels corresponding to red light, green light, and blue light, the luminous flux is spread, so that the luminous flux of each color is not accurately applied to the pixel corresponding to the desired color, and color mixing occurs. However, since the angle of incidence of a light beam of a desired color on the light valve can be reduced, it is possible to prevent color mixing while adjusting brightness and contrast.
[0075]
According to the present invention, there is provided a projection system for projecting the image light, comprising: an illumination optical system; and at least one light valve for modulating light from a light source guided through the illumination optical system to generate image light. In the type display device, the illumination optical system includes an integrator optical system that uniformly illuminates the light valve, and a light decomposing unit that spatially or temporally decomposes light from a light source into three color lights having different wavelength ranges. Light-shielding means for limiting an incident light flux angle to the light valve for one or two colors of the color light decomposed by the light decomposing means, wherein the light-shielding means adjusts the incident light flux angle to the light valve. Since variable control can be performed, control according to the projection state, use situation, application, and the like of the projection display device can be performed, and adjustment of the balance and contrast of each color becomes easy.
[0076]
According to the present invention, in the projection display device having the above-described configuration, the incident light flux angle limited by the light blocking unit is different for each of the red light, the green light, and the blue light. Even when the light use efficiency is different for each of the lights, the ON light level and the OFF light level can be simultaneously reduced according to the lowest light among the three colors, and the light use efficiency of the red light, the green light, and the blue light can be reduced. By making them equal, the balance of each color can be ensured. Further, by adjusting the balance of the red light, the green light, and the blue light to an appropriate ratio, a desired color temperature can be set.
[0077]
Further, according to the present invention, one of red light, green light, and blue light is incident on the light valve via a relay optical system including first, second, and third relay lenses in order from the light source side. Since the light blocking means is provided between the middle point between the first relay lens and the second relay lens and between the middle point between the second relay lens and the third relay lens, light is transmitted through the relay optical system. Even when the light is incident on the light valve, it is possible to provide a projection type display device with high contrast and high image quality without reducing the brightness while ensuring the balance of each color. Further, by disposing the light shielding means at a predetermined position in the relay optical system, it is possible to prevent color unevenness at the time of screen projection.
[0078]
Further, according to the present invention, the light shielding means has a dichroic characteristic of transmitting all the visible light in the central portion and reflecting light in a part of the wavelength band in the peripheral portion. This makes it possible to easily and reliably reduce only excess components of the red light, green light, and blue light of the illumination light from the light source by selecting the coating characteristics of the dichroic coat and adjusting the coating area.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a configuration of a projection type display device using a conventional reflection type light valve.
FIG. 2 is a schematic diagram showing a configuration of a conventional projection display device using a plurality of PBSs in an optical path.
FIG. 3 is a schematic diagram showing a relationship between color correction and brightness / contrast by conventional electrical control of a light valve.
FIG. 4 is a schematic diagram illustrating a relationship between an incident light beam and a reflected light beam with respect to a PBS.
FIG. 5 is a schematic diagram showing a configuration of a projection type display device using a conventional transmission type light valve.
FIG. 6 is a schematic diagram showing a projection display device according to the first embodiment of the present invention.
FIG. 7 is a schematic diagram showing an example of coating of a light shielding unit used in the present embodiment.
FIG. 8 is a graph showing coating characteristics of an AR coat and a dichroic coat used in the present embodiment.
FIG. 9 is a schematic optical path diagram after a light shielding unit in the present embodiment.
FIG. 10 is a schematic diagram illustrating a relationship between color correction by reducing the luminous flux angle and brightness / contrast according to the present embodiment.
FIG. 11 is a schematic diagram showing the effect of the present embodiment on PBS by reducing the luminous flux angle.
FIG. 12 is a schematic diagram showing an example in which the light shielding means can be variably controlled in the present embodiment.
FIG. 13 is a schematic view showing a position where the light shielding means can be arranged in the present embodiment.
FIG. 14 is a schematic diagram showing a projection display device according to a second embodiment of the present invention.
FIG. 15 is a schematic diagram illustrating a projection display device according to a third embodiment of the present invention.
FIG. 16 is a schematic diagram showing another embodiment of the light shielding means used in the present embodiment.
FIG. 17 is a schematic optical path diagram after a light shielding unit in the present embodiment.
FIG. 18 is a schematic diagram showing a projection display device according to a fourth embodiment of the present invention.
FIG. 19 is a schematic diagram showing a color balance before color correction in the embodiment.
FIG. 20 is a diagram showing characteristics and shapes of the light shielding means used in the present embodiment.
FIG. 21 is a schematic optical path diagram after a light shielding unit in the present embodiment.
FIG. 22 is a schematic diagram illustrating a projection display device according to a fifth embodiment of the present invention.
FIG. 23 is a schematic diagram illustrating a color balance before color correction in the present embodiment.
FIG. 24 is a graph showing coating characteristics of a dichroic coat used in the present embodiment.
FIG. 25 is a schematic optical path diagram after a light shielding unit in the present embodiment.
FIG. 26 is a schematic view showing a projection display device according to a sixth embodiment of the present invention.
FIG. 27 is a schematic diagram showing a position where the light shielding means can be arranged in the present embodiment.
FIG. 28 is a schematic diagram showing a projection display device according to a seventh embodiment of the present invention.
FIG. 29 is a schematic diagram showing a projection display device according to an eighth embodiment of the present invention.
[Explanation of symbols]
1. Shading means
3. AR coat
4. Dichroic coat
5. Shading means
15,16. Light bulb
17, 18. Dichroic mirror group
101. light source
102. First lens array
103. Second lens array
104. Superimposed lens
105. Dichroic mirror group
106. Dichroic mirror
109-111. PBS
112-114. Light bulb
115. Cross dichroic prism
116. Projection lens
117-119. Field lens
120-122. PBS
123. 1st relay lens
124. Second relay lens
125. Third relay lens
126. Relay optical system

Claims (5)

An illumination optical system, comprising at least one light valve that modulates light from a light source guided through the illumination optical system to generate image light, and a projection display device that projects the image light;
The illumination optical system includes an integrator optical system that uniformly illuminates the light valve, a light decomposing unit that spatially or temporally decomposes light from a light source into three color lights having different wavelength ranges, and the photodecomposition unit. Light-blocking means for limiting an incident light beam angle to the light valve for one or two colors of the color light decomposed by
A position conjugate with the light source by the integrator optical system, and a position conjugate with the light valve are present in the illumination optical system, and the light-shielding unit is provided with a position conjugate with the light source and a position conjugate with the light source. Two axes which are arranged on a position conjugate with the light source from a midpoint between adjacent light valve positions or positions conjugate with the light valve, and which pass through the optical axis center and are orthogonal to each other and form planes perpendicular to the optical axis. A projection display device, wherein an incident light beam is shielded in line symmetry with respect to the display device. An illumination optical system, comprising at least one light valve that modulates light from a light source guided through the illumination optical system to generate image light, and a projection display device that projects the image light,
The illumination optical system includes an integrator optical system that uniformly illuminates the light valve, a light decomposing unit that spatially or temporally decomposes light from a light source into three color lights having different wavelength ranges, and the photodecomposition unit. Light-blocking means for limiting an incident light beam angle to the light valve for one or two colors of the color light decomposed by
The projection type display device, wherein the light shielding means can variably control an incident light beam angle to the light valve. 3. The projection type display device according to claim 1, wherein an angle of a light beam incident on the light valve is different for each of three color lights having different wavelength ranges. Of the three color light paths having different wavelength ranges decomposed by the photodecomposition unit, the first light path is arranged on an optical path having a different optical path length as compared with the other color lights, and includes at least one lens in order from the light source side. , A relay optical system including a second and a third relay lens is provided in the illumination optical system,
The said light-shielding means is provided between the midpoint of the said 1st relay lens and a said 2nd relay lens, and from the midpoint of the said 2nd relay lens and a said 3rd relay lens, The claim 1 characterized by the above-mentioned. 4. The projection display device according to any one of 3. The said light-shielding means has a dichroic characteristic which transmits all the visible light in a center part, and reflects the light of a partial wavelength band in a peripheral part. 3. The projection display device according to 1.

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