JP2005012303A - Color separation optical system and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color separation optical system capable of obtaining the uniformity of a projection image by improving uniformity of illumination strength for a light valve, and to provide a projection display device. <P>SOLUTION: A plurality of luminous flux of B lights reflected on a dichroic mirror 14 go on through a first lens 17A and a conjugate position I section, are reflected by a deflection mirror 16, and is incident in a relay lens 17B. A plurality of third light source images of B lights which are conjugate with a plurality of second light source images on a second lens plate 12B are formed in an aperture diaphragm 17B-c conjugate with the position of second light source image on the second lens plate 12B. A plurality of luminous flux emitted from the third light source image are diffused through the relay lens 17B and diffused to be incident in a field lens 18B, and are converted into a luminous flux parallel to an axis. The luminous flux is incident into a projection lens 22 through a polarization beam splitter 19B, the light valve 20B, the polarization beam splitter 19B and a cross dichroic mirror prism 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color separation optical system and a projection display device.
[0002]
[Prior art]
The source light is separated into three primary colors of R (red) light, G (green) light, and B (blue) light by two dichroic mirrors, and each color light is reflected through a polarization beam splitter arranged for each color light. The light reflected by the reflective light valve is incident on the polarizing beam splitter, the modulated light is detected and extracted by this polarizing beam splitter, and the color is synthesized by the cross dichroic prism and projected by the projection lens. A projection type display device configured to do so is disclosed in Japanese Patent No. 2599309.
[0003]
This projection display device compares the optical path lengths from the light source of each color light to the light valve. The optical path lengths of the R light and the G light are the same, but the optical path length of the B light is clearly longer than the optical path length of the two-color light, and it is necessary to arrange a relay optical system in the middle of the optical path of the B light. is there. In addition, it is necessary to arrange an integrator that divides the light source light into a plurality of light beams and performs superimposed illumination on the light valve. Furthermore, it is necessary to dispose a field lens immediately before the entrance surface of each polarization beam splitter. A diagram to which these descriptions are added is shown as a diagram for explaining the conventional technology.
[0004]
FIG. 5 is a diagram showing a basic configuration of a conventional projection display apparatus.
[0005]
A substantially parallel light source light emitted from a light source 101 composed of a concave mirror such as a lamp and a parabolic mirror is illumination composed of a first lens plate 102A, a second lens plate 102B, and a condenser lens 103 for superimposed illumination. Incident into the optical system.
[0006]
The light emitted from the illumination optical system is incident on the first dichroic mirror 104 having the B light reflection characteristic disposed at an inclination of 45 degrees with respect to the optical axis, and B (blue) reflected by the first dichroic mirror 104; Color separation is performed into a mixed light of transmitting R (red) light and G (green) light.
[0007]
The mixed light of R light and G light is incident on a second dichroic mirror 105 having a G light reflection characteristic disposed in parallel to the first dichroic mirror 104, and is transmitted through the G light reflected by the second dichroic mirror 105. Color separation into R light. The first dichroic mirror 104 and the second dichroic mirror 105 constitute a color separation optical system.
[0008]
The color-separated R light and G light enter the polarization beam splitters 109R and 109G through the field lenses 108R and 108G, respectively. S-polarized light reflected by the polarization separation unit and emitted from the polarization beam splitters 109R and 109G is incident on the reflection type light valves 110R and 110G, respectively.
[0009]
The color-separated B light travels with the deflection mirror 106 changing the traveling direction by 90 degrees, and enters the field lens 108B through the first relay lens 107a and the second relay lens 107b constituting the relay optical system. The B light that has passed through the field lens 108B enters the polarization beam splitter 109B. The S-polarized light reflected from the polarization separation unit and emitted from the polarization beam splitter 109B enters the reflection type light valve 110B.
[0010]
The light incident on the reflective light valves for each color light 110R, 110G, and 110B is modulated by the color signal of each color light and reflected by the light valves for each color light 110R, 110G, and 110B. The light reflected by the light valves 110R, 110G, and 110B for each color light is incident on the polarization beam splitters 109R, 109G, and 109B again, and the P-polarized light that passes through the polarization separation unit is detected and extracted to form a color synthesis optical system. The incident light enters the cross dichroic prism 111 from different incident surfaces for each color light. The P-polarized light of the R light incident on the cross dichroic prism 111 is reflected by the R-light reflecting dichroic film 111R, the B light is reflected by the B-light reflecting dichroic film 111B, and the G light is transmitted through both the films 11R and 111B to combine colors. And is ejected from the ejection surface. The light incident on the projection lens 112 projects a full color image on a screen (not shown).
[0011]
FIG. 6 is an optical ray diagram for explaining the function of each member of the conventional projection display device. In FIG. 6, the light flux from the lens formed at the center and the outermost side of the first lens plate 102A is shown. The projection lens 112 includes an aperture stop 112C that determines the NA of light from the light valves 110R, 110G, and 110B. Furthermore, a principal ray defined as a ray passing through the central portion of the aperture stop 112C is described.
[0012]
As can be understood from this ray diagram, the principal ray is parallel to the optical axis at the position where the cross dichroic prism 111, the polarization beam splitters 109R, 109G, and 109B and the light valves 110R, 110G, and 110B are arranged, that is, telecentric. is there. The principal ray coincides with the ray emitted from the second light source image at the center of the second lens plate 102B, and the telecentric arrangement is secured by the field lenses 108R, 108G, and 108B.
[0013]
In the B light whose optical path length is different from the R light and the G light, the relay optical system composed of the first relay lens 107a and the second relay lens 107b is used. The first relay lens 107a has a function of taking light emitted from the imaging unit I in a conjugate position with the light valves 110R and 110G and guiding it to the second relay lens 107b. The relay optical system composed of the first relay lens 107a and the second relay lens 107b has a function of forming an image of the imaging portion I on the light valve 110B which is a conjugate position through the field lens 108B. Further, as can be understood from this ray diagram, a light source image of B light having a conjugate relationship with a plurality of second light source images formed on the second lens plate 102B is formed on the second relay lens 107b.
[0014]
The optical path length of the optical axis of each color light in this conventional example is compared. In the case of R light and G light, the optical path length from the first dichroic mirror 104 to the second dichroic mirror 105 is a, the optical path length from the second dichroic mirror 105 to the center of the polarization beam splitter 109R, 109G is b, When the distance from the center of the beam splitters 109R and 109G to the light valves 110R and 110G is c, the optical path lengths of the optical axes from the dichroic mirror 104 to the light valves 110R and 110G are a + b + c, respectively. In the case of B light, since the distance from the first dichroic mirror 104 to the deflecting mirror 106 is 2b and the distance from the deflecting mirror 106 to the light valve 110B is a + b + c, the optical path length of the optical axis from the first dichroic mirror 104 to the light valve 110B is a + 3b + c. It becomes. That is, the optical path length of the B light is 2b longer than the optical path lengths of the R light and the G light.
[0015]
[Patent Literature]
Japanese Patent No. 2599309
[0016]
[Problems to be solved by the invention]
However, in this projection type display device, the imaging of the illumination light beam becomes incomplete due to the spherical aberration of the second relay lens 107b on the B light valve 111B, resulting in uneven illumination intensity and projection. There is a problem that image uniformity cannot be obtained. On the other hand, a method using an aspherical lens as the second relay lens 107b is known, but even if an aspherical lens is used, unevenness in illumination intensity cannot be completely removed.
[0017]
The present invention has been made in view of such circumstances, and the subject thereof is a color separation optical system capable of improving the uniformity of the illumination intensity with respect to the light valve and obtaining the uniformity of the projected image, and a projection using the same. A type display device is provided.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, the invention according to claim 1
According to a second aspect of the present invention, in the color separation optical system according to the first aspect, a deflection mirror and a relay optical system are arranged in the optical path of the first color light color-separated by the first dichroic mirror. It is characterized by.
[0019]
According to a third aspect of the present invention, light from a light source is color-separated into a first color light, a second color light, and a third color light by a color separation optical system, and each color light separated by the color separation optical system is separated for each color light. In a projection type display device that enters the light valve disposed in the projector, modulates and emits the light, and color-synthesizes it with a color-synthesizing optical system, and projects the color-synthesized light with a projection lens. The light from the light source is arranged obliquely so that the incident angle with respect to the optical axis is less than 45 degrees, and the light from the light source is separated into first color light, mixed light of second color light and third color light. A first dichroic mirror that is arranged obliquely with respect to the incident optical axis, a second dichroic mirror that separates color light into second color light that reflects the mixed light and transmitted third color light, and the first dichroic mirror, The first color with the light bulb for the first color light And having a deflecting mirror and the relay optical system in the optical path of the.
[0020]
According to a fourth aspect of the present invention, in the projection type display device according to the third aspect, the light valve disposed for each color light is a reflection type light valve, and each of the color separated color lights is a field lens. And the polarization beam splitter, and enters the reflection light valve for each color light, extracts the analysis light by the polarization beam splitter, and performs color synthesis by the color synthesis optical system.
[0021]
According to a fifth aspect of the present invention, in the projection display device according to the third aspect, the light valve is a transmissive light valve, and the color-separated color lights are respectively incident on the field lens and the light valve. The light incident on the light valve through the polarizer disposed on the surface side, and the light emitted from the light valve is taken out as transmitted light of the polarizer disposed on the light exit surface side of the light valve, Color synthesis is performed by the color synthesis optical system.
[0022]
According to a sixth aspect of the present invention, light from a light source is color-separated into a first color light, a second color light, and a third color light by a color separation optical system, and each color light separated by the color separation optical system is separated for each color light. In a projection type display device that enters the light valve disposed in the projector, modulates and emits the light, and color-synthesizes it with a color-synthesizing optical system, and projects the color-synthesized light with a projection lens. The light from the light source is arranged obliquely so that the incident angle with respect to the optical axis is 45 degrees, and the light from the light source is separated into first color light, mixed light of second color light and third color light. A first dichroic mirror, a second dichroic mirror that is disposed in parallel with the first dichroic mirror and separates the mixed light into a second color light that reflects the mixed light and a third color light that passes therethrough; the second dichroic mirror; Between light bulbs for three-color light An optical path length from the light source to the light valve for the third color light, the optical path length from the light source to the first color light and the second color light. The optical path length of the first color light and the second color light to the light valve is larger than the optical path length of the optical axis between the first dichroic mirror and the second dichroic mirror. Characterized by being enlarged.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0024]
FIG. 1 is a plan view for explaining the configuration of a projection display apparatus according to the first embodiment of the present invention, and FIG. 2 is an optical ray diagram thereof.
[0025]
A substantially parallel light source light beam emitted from a light source 11 composed of a lamp and a concave mirror such as a parabolic mirror includes a first lens plate 12A having a plurality of lenses 12A-a arranged in a matrix, and a lens 12A-. The lens 12B-a is incident on an illumination optical system including a condenser lens 13 and an integrator 12 including a second lens plate 12B in which lenses 12B-a are arranged in a matrix corresponding to a. The light source light beam is divided into a plurality of intermediate light beams by the lens 12A-a of the first lens plate 12A. Each light beam enters the lens 12B-a of the corresponding second lens plate and is condensed to form a plurality of second light source images. A plurality of light beams emitted from the second light source image enter the condenser lens 13 and are illuminated by being superimposed on the reflection type light valves 20R, 20G, and 20B.
[0026]
The light emitted from the condenser lens 13 is incident on a dichroic mirror 14 disposed so that an incident angle with respect to the incident optical axis (an angle formed by the incident optical axis and the normal of the incident surface is less than 45 degrees). Has a characteristic of reflecting blue (B) light and transmitting red (R) light and green (G) light, and the dichroic mirror 14 is a mixed light of R light and G light transmitted in the same direction as the optical axis. And the B light reflected at a reflection angle of less than 45 degrees which is the same as the incident angle with respect to the normal line perpendicular to the dichroic mirror 14. As shown in the figure, the dichroic mirror 14 The reflected B light travels diagonally backward.
[0027]
The R light and G light that pass through the dichroic mirror 14 are incident on the G light reflecting dichroic mirror 15 arranged so that the incident angle with respect to the incident optical axis is 45 degrees, and the R light that is transmitted and the reflected G light. And color separation. The R light and the G light are incident on the polarization beam splitters 19R and 19G through the field lenses 18R and 18G, respectively. The respective color lights incident on the polarization beam splitters 19R and 19G are reflected by the polarization separation unit, emitted from the exit surface, and enter the reflection type light valves 20R and 20G arranged near the exit surface.
[0028]
The B light reflected by the dichroic mirror 14 is arranged substantially parallel to the first dichroic mirror 14 through the first lens 17A of the relay lens 17B and the first lens 17A having the function of a field lens constituting the relay optical system. The incident light enters the deflecting mirror 16. The B light is incident on the deflecting mirror 16 at an incident angle of the incident optical axis that is the same as the incident angle on the dichroic mirror 14. The B light is reflected by the deflecting mirror 16, travels substantially parallel to the mixed light of the R light and G light transmitted through the dichroic mirror 14, and enters the field lens 18B through the relay lens 17B. The B light that has passed through the field lens 18B enters the polarization beam splitter 19B. The B light incident on the polarization beam splitter 19B is reflected by the polarization separation unit, exits from the exit surface, and enters the reflection light valve 20B for B light disposed near the exit surface.
[0029]
Each color light incident on the light valves 20R, 20G, and 20B for each color light is modulated by a color signal, and mixed light of modulated light whose polarization direction is changed and unmodulated light having the same polarization direction as the incident polarization. reflect. The light emitted from the light valves 20R, 20G, and 20B again enters the polarization beam splitters 19R, 19G, and 19B for each color light, and is polarized and separated into modulated light and non-modulated light by the polarization separation unit. A composite prism configuration in which modulated light is analyzed and extracted as light passing through a polarization separation unit, and an R light reflecting dichroic film 21R and a B light reflecting dichroic film 21B constituting a color synthesizing optical system are disposed inside at right angles to each other. The cross dichroic rhythm 21 is made incident from different incident surfaces. The B light incident on the cross dichroic rhythm 21 is reflected by the B light reflecting dichroic film 21B, the R light is reflected by the R light reflecting dichroic film 21R, and the G light is transmitted through both films 21B and 21R, and is color-combined and emitted. Ejected from the face. The combined light enters the projection lens 22 and is enlarged and projected on a screen (not shown).
[0030]
Next, the optical ray diagram of FIG. 2 will be described. FIG. 2 illustrates three light beams formed by the central lens 12A-a and the outermost lens 12A-a of the first lens plate 12A out of the light beam from the light source 11.
[0031]
The intermediate light beam emitted from the second light source image on the lens 12B-a of the second lens plate 12B passes through the condenser lens 13 and travels as a diffused light beam, passes through the dichroic mirror 14, and is emitted by the dichroic mirror 15. Color separation is performed into R light and G light whose axes are orthogonal to each other, and the entire light valves 20R and 20G are superimposed and illuminated through the field lenses 18R and 18G and the polarization beam splitters 19R and 19G. The light beam from the light source on the central lens 12B-a at the position of the optical axis of the second lens plate 12B travels parallel to the optical axis through the field lenses 18R and 18G and enters the light valves 20R and 20B. . The R light and G light are reflected by the light valves 20R and 20B, travel through the polarization beam splitters 19R and 19G and the cross dichroic prism 21 in parallel to the optical axis, and enter the projection lens 22. Since the projection lens 22 is telecentricly formed on the light valves 20R and 20G side, the projection lens 22 is focused on the central portion of the aperture stop 22c disposed inside the projection lens 22 and emitted from the central portion while diffusing. To do. That is, with respect to the cross dichroic prism 21, the polarization beam splitters 19R and 19G, and the light valves 20R and 20G, the principal ray defined by the aperture stop 22c of the projection lens 22 is arranged at a so-called telecentric position parallel to the optical axis. Yes.
[0032]
On the other hand, a plurality of light beams of B light reflected by the dichroic mirror 14 travel through the first lens 17A and the conjugate position I portion, are reflected by the deflecting mirror 16, and enter the relay lens 17B. The aperture stop 17B-c of the relay lens 17B is conjugate with the position of the second light source image on the second lens plate 12B, and a plurality of second light source images on the second lens plate 12B are contained in the aperture stop 17B-c. A plurality of third light source images of the B light conjugate with the first light source image are formed. The plurality of light beams emitted from the third light source image are diffused through the relay lens 17B and enter the field lens 18B. The light beam from the third light source image formed at the center of the aperture stop 17B-c of the relay lens 17B is converted into a light beam parallel to the axis through the field lens 18B. The light beam passes through the polarizing beam splitter 19B, the light valve 20B, the polarizing beam splitter 19B, and the cross dichroic prism 21, enters the projection lens 22, and is collected at the center of the aperture stop 22c of the projection lens 22. Regarding the B light, similarly to the R light and G light, with respect to the polarization beam splitter 19B, the light valve 20B, and the cross dichroic prism 21, the principal ray defined by the aperture stop 22c of the projection lens 22 is in a telecentric position.
[0033]
As can be understood from the ray diagram of the B light, the conjugate position I and the light valve 20B have a conjugate relationship with respect to the relay lens 17B.
[0034]
Further, as can be understood from the ray diagram of the B light, the relay lens 17B can be disposed at a position where the respective optical path lengths from the polarization beam splitter 19B and the conjugate position I are made larger. By increasing the optical path length, the spread angle of each light beam emitted from the plurality of third light source images in the aperture stop 17B-c of the relay lens 17B and spread over the entire light valve 20B is suppressed. It becomes possible.
[0035]
According to this embodiment, the power of the lens of the field lens 18B can be reduced. In addition, the field lens 18B can be used to achieve the telecentric state, and the light bulb 20B can be overlaid. Further, the uniformity of the illumination intensity can be improved as compared with the conventional example, and the uniformity of the projected image can be obtained.
[0036]
The lengths of the optical axes of the respective color lights in the projection display device according to this embodiment are compared. In the case of R light and G light, the optical path length from the dichroic mirror 14 to the dichroic mirror 15 is a, the optical path length from the dichroic mirror 15 to the center of the polarization beam splitters 19R and 19G is the same b, and the polarization beam splitters 19R and 19G. When the distance from the center to the light valves 20R and 20G is c, the optical path lengths of the optical axes from the dichroic mirror 14 to the light valves 20R and 20G are a + b + c. In the case of B light, the optical path length from the dichroic mirror 14 to the deflecting mirror 16 is greater than 2b, and from the deflecting mirror 16 to the light valve 20B is greater than a + b + c, so the optical path of the optical axis from the dichroic mirror 14 to the light valve 20B The length is greater than a + 3b + c. That is, when the optical path length of the B light to the light valve 20B is compared with the optical path lengths of the R light and G light, the difference is greater than 2b. As described above, the optical path length difference in the conventional example is 2b.
[0037]
In this embodiment, the B light is reflected by the dichroic mirror 14, and the mixed light of the R light and the G light transmitted through the dichroic mirror 14 is separated into colors. However, as another embodiment, the B light is dichroic. A configuration may be adopted in which color separation is performed with mixed light of R light and G light that is transmitted through the mirror 14 and reflected by the dichroic mirror 14. At that time, it is necessary to change the optical characteristics of the dichroic mirror 14, the arrangement of the light source 11, the integrator 12, and the condenser lens 13. Further, the monochromatic light that is reflected or transmitted by the dichroic mirror 14 and is color-separated is not limited to B light, and can be G light or R light depending on the optical characteristics of the dichroic mirror 14. At that time, the color separation optical system is configured by changing the optical characteristics of the dichroic mirror 14.
[0038]
FIG. 3 is a plan view for explaining the configuration of a projection display apparatus according to the second embodiment of the present invention.
[0039]
This embodiment differs from the first embodiment in that a transmissive light valve is used.
[0040]
The configuration of the color separation optical system is substantially the same as that of the first embodiment. The light source light emitted from the light source 31 passes through the integrator 32 and the condenser lens 33 having the same configuration as in the first embodiment, and is arranged so that the incident angle of the incident optical axis is less than 45 degrees. The light is incident on the mirror 34 and is separated into B light reflected and mixed light of R light and G light.
[0041]
The mixed light of R light and G light is incident on the G light reflecting dichroic mirror 35 arranged so that the incident angle of the incident optical axis is 45 degrees, and is separated into reflected G light and transmitted R light. Is done. The G light is reflected by the reflection deflection mirror 39G and enters the field lens 38G, and then enters the transmission type light valve 40G sandwiched between the two polarizers through the field lens 38G. The R light is reflected by the reflection deflecting mirror 39R, enters the field lens 38R, and enters the transmission light valve 40R sandwiched between the two polarizers through the field lens 38R. The B light reflected by the dichroic mirror 34 passes through the lens 37A of the relay lens optical system including the lens 37A and the relay lens 37B as in the first embodiment, and is deflected substantially parallel to the dichroic mirror 34. Incident on the mirror 36. The B light reflected by the deflection mirror 36 travels substantially parallel to the mixed light of the G light and the R light transmitted through the dichroic mirror 34, and enters the reflection deflection mirror 39B through the relay lens 37B. The B light reflected by the reflection deflecting mirror 39B passes through the field lens 38B and is incident on a transmission light valve 40B for B light having the same structure as the light valves 40R and 40G for R light and G light.
[0042]
Polarized light that has passed through a polarizer disposed on the incident surface side of the light valves 40R, 40G, and 40B for each color light enters the light valves 40R, 40G, and 40B, is modulated by color signals, and is modulated light and non-modulated light. And emitted as mixed light. The transmitted light is detected and extracted by a polarizer disposed on the exit surface side, and is incident on the cross dichroic prism 41 of the color synthesis optical system from different entrance surfaces. The color lights incident on the cross dichroic prism 41 are color-combined and emitted from the exit surface. The combined light enters the projection lens 42 and is enlarged and projected onto a screen (not shown).
[0043]
In this embodiment, since the ray diagram is substantially the same as the ray diagram of the first embodiment, its illustration is omitted, but the integrator 32, the condenser lens 33, the lens 37A, the relay lens 37B, and the field lenses 38R, 38G, and 38B. The roles and functions thereof are the same as those in the first embodiment.
[0044]
The lengths of the optical axes of the respective color lights in the projection display device according to this embodiment are compared. In the case of R light and G light, the optical path length from the dichroic mirror 34 to the dichroic mirror 35 is a, the optical path length from the dichroic mirror 35 to the deflecting mirrors 39R and 39G is the same b, and the mirrors 39R and 39G to the light valve 40R. Assuming that the optical path length up to 40G is c, the optical path lengths of the optical axes from the dichroic mirror 34 to the light valves 40R and 40G are a + b + c, respectively. In the case of B light, the optical path length from the dichroic 34 to the deflecting mirror 36 is greater than 2b, and the optical path length from the deflecting mirror 36 to the light valve 40B is greater than a + b + c, so the optical axis from the dichroic mirror 34 to the light valve 40B. Is longer than a + 3b + c. In other words, the optical path length of the B light to the light valve is 2b longer than the optical path lengths of the R light and G light.
[0045]
According to this embodiment, the same effect as that of the first embodiment can be obtained, and the illumination on the transmission type light valve can be made uniform, in particular, the uniform illumination to the light valve 40B of the B light having a long optical path length can be achieved. The uniformity of the projected image can be achieved.
[0046]
In this embodiment, the color separation method using the dichroic mirrors 34 and 45 is also possible as in the first embodiment.
[0047]
FIG. 4 is a plan view for explaining the configuration of a projection type display apparatus according to the third embodiment of the present invention. The parts common to the second embodiment are denoted by the same reference numerals and the description thereof is omitted.
[0048]
The light source light from the light source 31 passes through the integrator 32 and the condenser lens 33 and is arranged so that the incident angle of the incident optical axis is 45 degrees, transmits the R light, and reflects the mixed light of the G light and the B light. The light is incident on the dichroic mirror 54 having characteristics and is separated into R light that is transmitted and light that is mixed with reflected G light and B light. The color-separated R light is incident on the field lens 38R by the reflection deflection mirror 56R arranged in parallel with the dichroic mirror 54, and is incident on the transmission light valve 40R through the field lens 38R.
[0049]
The mixed light of B light and G light is incident on a dichroic mirror 55 that reflects G light disposed substantially parallel to the dichroic mirror 54, and is color-separated into reflected G light and transmitted B light. The color-separated G light is incident on the transmissive light valve 40G through the field lens 38G.
[0050]
The B light color-separated as the transmitted light of the dichroic mirror 55 passes through the lens 58A of the relay optical system including the lens 58A and the relay lens 58B, and enters the deflection mirror 57B arranged in parallel with the dichroic mirrors 54 and 55. The B light is reflected by the deflecting mirror 57B, passes through the relay lens 58B, and enters the deflecting mirror 56B arranged so as to be orthogonal to the deflecting mirror 57B. The B light is reflected by the deflecting mirror 56B and enters the transmissive light valve 40B through the field lens 38B.
[0051]
The analysis light emitted from the exit surface side polarizer enters the cross dichroic prism 41 of the color synthesis optical system, and is color-combined and emitted from the exit surface. The combined light enters the projection lens 42 and is enlarged and projected onto a screen (not shown).
[0052]
The optical path length to the light valves 40R, 40G, and 40B of the optical axes of the respective color lights will be described. When the optical path length from the R light dichroic mirror 54 to the light valve 40R is a, the optical path length from the G light dichroic mirror 54 to the dichroic mirror 55 is b, and the optical path length from the dichroic mirror 55 to the light valve 40G is c. A = b + c. The optical path length of the B light from the dichroic mirror 54 to the dichroic mirror 55 is b as in the G light, and the optical path length from the dichroic mirror 55 to the deflection mirror 57B is larger than b. The distance from the deflecting mirror 57B to the light valve 40B is larger than a (= b + c). That is, the optical path length from the dichroic mirror 54 to the light valve 40B is larger than 3b + c. Therefore, when comparing the optical path length (a = b + c) from the dichroic mirror 54 to the light valves 40R, 40G of the optical axis of the R light and G light and the optical path length from the dichroic mirror 54 of the B light to the light valve 40B, the difference Is greater than 2b.
[0053]
According to this embodiment, there is an effect similar to that of the first embodiment and the second embodiment.
.
【The invention's effect】
As described above, according to the present invention, the uniformity of the projection intensity can be obtained by improving the uniformity of the illumination intensity with respect to the light valve.
[Brief description of the drawings]
FIG. 1 is a plan view illustrating a configuration of a projection display device according to a first embodiment of the present invention.
FIG. 2 is an optical ray diagram of the projection display apparatus according to the first embodiment of the present invention.
FIG. 3 is a plan view for explaining the configuration of a projection display apparatus according to a second embodiment of the present invention.
FIG. 4 is a plan view for explaining the configuration of a projection display apparatus according to a third embodiment of the present invention.
FIG. 5 is a diagram showing a basic configuration of a conventional projection display device.
FIG. 6 is an optical ray diagram illustrating the function of each member of a conventional projection display device.
[Explanation of symbols]
11, 31 Light source
12, 32 Integrator
13, 33 condenser lens
14, 15, 34, 35, 54, 55 Dichroic mirror
16, 36, 39R, 39G, 39B, 56R, 56B, 57B Reflective deflection mirror
17A, 37A, 58A lenses
17B, 37B, 58B Relay lens
18R, 18G, 18B, 38R, 38G, 38B Field lens
19R, 19G, 19B Polarizing beam splitter
20R, 20G, 20B Reflective light valve
40R, 40G, 40B Transmission type light valve
21, 41 Cross dichroic prism
22, 42 Projection lens

Claims (6)

A first dichroic mirror disposed obliquely with respect to the optical axis of the light from the light source, and color-separating the light from the light source into a first color light and a mixed light of the second color light and the third color light; and incident light In a color separation optical system configured by a second dichroic mirror that is disposed obliquely with respect to the axis and separates the mixed light of the second color light and the third color light into the second color light and the third color light,
The color separation optical system, wherein an incident angle of an optical axis of light from the light source of the first dichroic mirror to the first dichroic mirror is less than 45 degrees. 2. The color separation optical system according to claim 1, wherein a deflection mirror and a relay optical system are disposed in an optical path of the first color light color-separated by the first dichroic mirror. The light from the light source is separated into the first color light, the second color light, and the third color light by the color separation optical system,
Each color light color-separated by the color separation optical system is incident on a light valve arranged for each color light, modulated and emitted, color-synthesized by a color synthesis optical system, and the color-synthesized light is projected into a projection lens. In the projection type display device that projects in
The color separation optical system is
The light from the light source is arranged obliquely so that the incident angle with respect to the optical axis is less than 45 degrees, and the light from the light source is separated into first color light, mixed light of second color light and third color light. A first dichroic mirror that
A second dichroic mirror disposed obliquely with respect to the incident optical axis and color-separating into a second color light reflecting the mixed light and a third color light transmitting;
A projection type display apparatus comprising: a deflection mirror and a relay optical system in an optical path of the first color light between the first dichroic mirror and a light valve for first color light. The light valves arranged for the respective color lights are reflection type light valves, and the respective color light components separated by color are incident on the reflection type light valves for the respective color lights through a field lens and a polarization beam splitter, respectively. 4. The projection display device according to claim 3, wherein the analyzing light is taken out by the polarization beam splitter and color synthesis is performed by the color synthesis optical system. The light valve is a transmissive light valve, and the color-separated color lights enter the light valve through a field lens and a polarizer disposed on the incident surface side of the light valve, The light emitted from the light valve is extracted as light for analysis through a polarizer disposed on the light exit surface side of the light valve, and color synthesis is performed by the color synthesis optical system. Projection type display device. The light from the light source is separated into the first color light, the second color light, and the third color light by the color separation optical system,
Each color light color-separated by the color separation optical system is incident on a light valve arranged for each color light, modulated and emitted, color-synthesized by a color synthesis optical system, and the color-synthesized light is projected into a projection lens. In the projection type display device that projects in
The color separation optical system is
The light from the light source is arranged obliquely so that the incident angle with respect to the optical axis is 45 degrees, and the light from the light source is separated into first color light, mixed light of second color light and third color light. The first dichroic mirror,
A second dichroic mirror disposed in parallel with the first dichroic mirror and color-separating into a second color light reflecting the mixed light and a third color light transmitting;
A deflecting mirror disposed in an optical path between the second dichroic mirror and the light valve for the third color light, and a relay optical system;
The optical path length of the optical axis from the light source to the light valve for the third color light is the optical axis of the first color light and the second color light from the light source to the light valve of the first color light and the second color light. And an optical path length between the first dichroic mirror and the second dichroic mirror greater than twice the optical path length of the first dichroic mirror.

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