JP2011191480A - Projector - Google Patents

Abstract

A projector capable of reducing the size of an illumination optical system by shortening the distance from a light source to a liquid crystal panel.
A color separation light-guiding unit 40 directly applies a red light LR as a first color light separated by a first dichroic mirror 41a as a separation mirror to a first liquid crystal light valve 50a as a first light modulation device. Therefore, the distance from the illumination unit 10 to the first liquid crystal light valve 50a can be shortened, and the size of the projector 100 can be reduced by downsizing the illumination unit 10.
[Selection] Figure 1

Description

  The present invention relates to a projector that projects an image formed by illuminating a light-transmissive liquid crystal panel or the like onto a screen.

  As a projector, the light beam from the light source is sequentially branched into three colors by two dichroic mirrors, and the relay lenses are made unnecessary by matching the optical axis paths of the three colors emitted from the dichroic prism for synthesis, and There is one in which the number of times of light beam reflection is made to be an even difference between the colors so that the top, bottom, left, and right after the synthesis of the colors are matched (see Patent Document 1).

  As another projector, the light beam from the light source is sequentially split into three colors by two dichroic mirrors, the optical axis paths of the two light beams incident on the dichroic prism for synthesis are matched, and the remaining one light beam is relayed by a relay lens. There is one that inverts twice and makes the number of reflections of light beams an even number difference between the colors so that the upper, lower, left, and right after the synthesis of the respective colors coincide with each other (see Patent Document 2).

Japanese Patent Laid-Open No. 11-237588 JP-A-10-206815

  However, in the projectors described in Patent Documents 1 and 2, if the viewing angle is to be ensured, the distance from the light source to the liquid crystal panel is increased, and the size of the illumination optical system is increased.

  SUMMARY An advantage of some aspects of the invention is to provide a projector that can reduce the size of an illumination optical system by shortening the distance from a light source to a liquid crystal panel.

  In order to solve the above-described problem, a projector according to the present invention includes a lighting unit including a light source, and a first color light having a predetermined wavelength among light emitted from the lighting unit, and a second color light having another wavelength by transmission. A color separation light-guiding unit having a separation mirror that separates the first color light, a light modulation unit having a first light modulation device that modulates the separated first color light, and a second light modulation device that modulates the separated second color light; A color combining unit that combines the modulated first color light and the second color light to form image light, and a projection optical system that projects the formed image light. The color separation light guide unit causes the first color light separated by the separation mirror to directly enter the first light modulation device and transfers the second color light separated by the separation mirror by projecting twice. The color combining unit has a double relay optical system, and the color combining unit includes a first light incident surface on which the first color light that has passed through the first light modulator is incident, and a second light on which the second color light that has passed through the second light modulator is incident. A light incident surface, a reflective surface that reflects the first color light incident from the first light incident surface, and a light exit surface that faces the projection optical system. The difference between the number of times the optical path is bent due to the reflection of the one color light and the number of times the optical path is bent due to the reflection of the second color light is an even number. Here, direct incidence of the first color light to the first light modulation device means that no optical element accompanied by inversion of a mirror or the like is interposed, and an optical element without inversion of a field lens or the like is interposed. It may be.

  According to the projector, the color separation light guide unit causes the first color light separated by the separation mirror to directly enter the first light modulation device, and projects the second color light separated by the separation mirror twice. Since the double relay optical system is transferred, the effect of the mirror reversal by the mirror (where left and right means the in-plane direction on the reference plane where the system optical axis is present) on the light exit surface of the color composition unit Is neglected, the second color light image can be erected with respect to the first color light image. Furthermore, since the difference between the number of times of bending of the optical path due to reflection relating to the first color light and the number of times of bending of the optical path due to reflection relating to the second color light is an even number, the image of the second color light is a mirror image with respect to the image of the first color light. Inversion can be prevented. That is, the first light modulation device and the second light modulation device can be illuminated with their upper, lower, left, and right aligned, and the image light from these can be combined with their upper, lower, left, and right aligned. As a result, luminance unevenness and color unevenness of the projected image can be reduced. Further, according to the projector, the color separation light guide unit directly causes the first color light separated by the separation mirror to enter the first light modulation device, so that the distance from the illumination unit to the first light modulation device is increased. The projector can be shortened, and the size of the projector can be reduced by downsizing the illumination unit.

  Further, according to a specific aspect or aspect of the present invention, in the projector, the illumination unit is disposed between the light source and the color separation light guide unit and emitted from the light source in a plane orthogonal to the system optical axis. A color-separating light-guiding unit disposed between the color-separating light-guiding unit and the first light modulator to adjust the state of the first color light passing therethrough The effective diameter of the uniformizing optical system is substantially equal to the effective diameter of the emission field lens. In this case, since the illumination unit is reduced in size in the effective diameter direction, the projector can be reduced in thickness.

  According to another aspect of the present invention, the double relay optical system includes a first intermediate field lens disposed in the vicinity of the first conjugate position corresponding to the position of the first light modulation device, and an image at the first conjugate position. A first relay system having a first condensing lens that forms an image at a second conjugate position, a second intermediate field lens disposed in the vicinity of the second conjugate position, and an image at the second conjugate position as a second light modulation And an effective diameter of the first intermediate field lens and the second intermediate field lens is substantially equal to the effective diameter of the exit field lens. . In this case, the illumination of the second light modulation device by the second color light can be equivalent to the illumination of the first light modulation device by the first color light, and the loss of the second color light can be suppressed.

  According to still another aspect of the present invention, the first condenser lens and the second condenser lens are formed of heavy flint optical glass. In this case, the first and second condenser lenses can be reduced in size, and the size of the color separation light guide can be reduced.

  According to still another aspect of the present invention, the color separation light-guiding unit separates the third color light having a wavelength different from the first color light and the second color light from the light emitted from the illumination unit. And a second double relay optical system that transfers the third color light separated by the second separation mirror by projecting it twice, and the light modulation section outputs the separated third color light. A third light modulation device that modulates the light path; the number of times that the light path is bent due to reflection with respect to the first color light and the number of times that the light path is bent due to reflection with respect to the third color light; The difference is even. In this case, it is possible to illuminate the first light modulation device and the third light modulation device in the same direction, and to synthesize the image light from these in the same direction.

  According to still another aspect of the present invention, the first color light is light having a wavelength with relatively weak light intensity emitted from the light source. In this case, it is possible to synthesize the image light that minimizes the loss of the first color light, and it is easy to adjust the color balance.

It is a conceptual diagram explaining the optical system of the projector which concerns on one Embodiment of this invention.

  Hereinafter, a projector 100 according to an embodiment of the invention will be described with reference to FIG. In FIG. 1 and the like, X, Y, and Z mean three coordinate axes that constitute a three-dimensional orthogonal coordinate system in the projector 100. Of these, the YZ plane formed by two axes is parallel to a reference plane in which the system optical axis SA, which is the central axis of the light beam passing through the projector 100, extends two-dimensionally.

  As shown in FIG. 1, the projector 100 according to this embodiment includes an illumination unit 10, a color separation light guide unit 40, a light modulation unit 50, a color synthesis unit 60, and a projection optical system 70.

  First, the illumination unit 10 is an illumination optical system that includes a light source lamp unit 20 and a uniformizing optical system 30.

  Among the illumination units 10, the light source lamp unit 20 includes a lamp unit 21a and a concave lens 21b as light sources. Among these, the lamp unit 21a includes an arc tube 22a such as a high-pressure mercury lamp, and an elliptical concave mirror 22b that reflects the light beam emitted from the arc tube 22a and emits it forward. The concave lens 21b has a role of making the illumination light LF from the lamp unit 21a substantially parallel to the system optical axis SA, but may be omitted when the concave mirror 22b is a parabolic mirror, for example.

  The homogenizing optical system 30 includes first and second lens arrays 31 and 32, a polarization conversion member 34, and a superimposing lens 36. Among these, the first and second lens arrays 31 and 32 are flyers each including a plurality of element lenses 31a and 32a arranged in a matrix with respect to the X direction (ie, the x direction) and the Y direction (ie, the y direction). Eye lens. Among these, the illumination light LF emitted from the light source lamp unit 20 is divided into a plurality of partial light beams by the plurality of element lenses 31 a constituting the first lens array 31. In addition, each of the partial light beams incident from the first lens array 31 is emitted to the polarization conversion member 34 side with an appropriate divergence angle by the plurality of element lenses 32a constituting the second lens array 32. The polarization conversion member 34 is a rectangular flat plate member that is parallel to the XY plane as a whole, and is formed by arranging a plurality of polarization conversion elements 34a extending in the Y direction in the X direction. Each polarization conversion element 34a is a prism-like member composed of a PBS, a mirror, a half-wave plate, or the like. The polarization conversion member 34 converts the illumination light LF emitted from the lens array 32 into only linearly polarized light in a specific direction and emits it to the superimposing lens 36 side. The superimposing lens 36 appropriately superimposes the illumination light LF emitted from the second lens array 32 and passing through the polarization conversion member 34 as a whole, thereby superimposing the light on the liquid crystal light valves 50a, 50b, and 50c of each color provided in the light modulation unit 50. Enable lighting. Here, the superimposing lens 36 is formed of a material having a high refractive index of, for example, a refractive index of 1.7 or more, and the F number of the illumination unit 10 is set to 2.0 or less by adjusting the focal length.

  The color separation light guide 40 includes a first dichroic mirror 41a, a second dichroic mirror 41b, four reflection mirrors 42a, 42b, 42c, and 42d, three intermediate field lenses 44a, 45b, and 46b, and two first 1 condenser lenses 45a, 46a, two second condenser lenses 45c, 46c, and three exit field lenses 43a, 43b, 43c, and the illumination light LF emitted from the illumination unit 10 is red (R). The color light, green (G) color, and blue (B) color are separated, and the separated color lights are led to the subsequent liquid crystal light valves 50a, 50b, and 50c in a substantially equivalent state. Here, the intermediate field lenses 44a and 45b and the first and second condenser lenses 45a and 45c constitute a first double relay optical system 81 as a whole, and the intermediate field lenses 44a and 46b, The second condensing lenses 46a and 46c constitute a second double relay optical system 82 as a whole.

  In the color separation light guide 40, the red light LR among the three colors RGB separated by the first and second dichroic mirrors 41a and 41b is guided to the first optical path OP1 that travels straight, and the green light LG is The detour second light path OP2 is guided, and the blue light LB is guided to the detour third optical path OP3. More specifically, the first dichroic mirror 41a is a separation mirror for separating the red light LR from other light, and transmits the red light LR out of the illumination light LF incident on the color separation light guide 40. The green light LG and the blue light LB are reflected. The second dichroic mirror 41b is a second separation mirror for separating the green light LG and the blue light LB, and the green light LG of the green light LG and the blue light LB reflected by the first dichroic mirror 41a. And blue light LB is reflected. That is, the red light LR that has passed through the first dichroic mirror 41a travels straight in the + Z direction in the shortest first optical path OP1. On the other hand, the green light LG reflected by the first dichroic mirror 41a in the −Y direction and transmitted through the second dichroic mirror 41b is once bent in the + Z direction by the reflection mirrors 42a and 42b in the relatively long second optical path OP2. Finally, it moves backward in the + Y direction. Further, the blue light LB reflected in the −Y direction by the first dichroic mirror 41a and reflected in the + Z direction by the second dichroic mirror 41b is temporarily + Zed by the reflecting mirrors 42c and 42d in the relatively long third optical path OP3. It is bent in the + Y direction from the direction and finally moves backward in the -Z direction.

  On the second and third optical paths OP2 and OP3 between the first and second dichroic mirrors 41a and 41b, that is, immediately before the green light LG and the blue light LB are branched, the position of an R color liquid crystal panel 51a to be described later There is a first conjugate position C1 corresponding to. Further, in correspondence with the provision of the first double relay optical system 81 on the light incident side of the reflection mirror 42b, that is, on the second optical path OP2 where the green light LG travels in the + Z direction alone, the first conjugate. There is a second conjugate position C2 where a conjugate image of the position C1 is formed. Further, in correspondence with the provision of the second double relay optical system 82 on the light incident side of the reflecting mirror 42c, that is, on the third optical path OP3 in which the blue light LB travels in the + Z direction alone, the first conjugate. There is a second conjugate position C2 where a conjugate image of the position C1 is formed.

  In the second optical path OP2 of the green light LG, a first relay system 81a including an intermediate field lens 44a and a first condenser lens 45a is disposed. The intermediate field lens 45b and the second condenser lens 45c A second relay system 81b is arranged. Both relay systems 81 a and 81 b function as a first double relay optical system 81.

  Specifically, in the first and second optical paths OP2 and OP3 before branching common to the green light LG and the blue light LB, the first relay is located in the vicinity of the upstream side of the optical path facing the first conjugate position C1. An intermediate field lens 44a, which is one element of the system 81a, is disposed. Further, in the branched second optical path OP2 through which the green light LG passes alone, it is an intermediate position between the first and second conjugate positions C1 and C2, and is between the second dichroic mirror 41b and the reflection mirror 42a. A first condenser lens 45a, which is another element of the first relay system 81a, is disposed. The former intermediate field lens 44a has a role of making the principal rays substantially parallel to each other with respect to the luminous flux (green light LG) from each point on the first conjugate position C1. The latter first condenser lens 45a is an aspherical lens formed of a high refractive index material (for example, heavy flint optical glass) having a refractive index of 1.7 or more, and a light beam from the first conjugate position C1. Is condensed at the second conjugate position C2 to prevent a decrease in light use efficiency due to light diffusion or the like.

  Further, in the branched second optical path OP2, an intermediate field lens 45b that is one element of the second relay system 81b is disposed in the vicinity of the upstream side of the optical path so as to face the second conjugate position C2. Further, in the branched second optical path OP2, it is an intermediate position between the second conjugate position C2 and the liquid crystal panel 51b, and on the light emission side of the reflection mirror 42b, is another element of the second relay system 81b. A second condenser lens 45c is disposed. The former intermediate field lens 45b has a role of making the principal rays substantially parallel to each other with respect to the light flux (green light LG) from each point on the second conjugate position C2. The second condenser lens 45c is an aspherical lens made of a high refractive index material (for example, heavy flint optical glass) having a refractive index of 1.7 or more, and a light beam from the second conjugate position C2. Is condensed at the position of the liquid crystal panel 51b for G color to prevent a decrease in light use efficiency due to light diffusion or the like.

  Similarly, a first relay system 82a including an intermediate field lens 44a and a first condenser lens 46a is disposed in the third optical path OP3 of the blue light LB, and the intermediate field lens 46b and the second condenser lens 46c. The 2nd relay system 82b comprised by these is arrange | positioned. Both relay systems 82a and 82b function as the second double relay optical system 82.

  Specifically, in the first and second optical paths OP2 and OP3 before branching common to the green light LG and the blue light LB, the intermediate field lens 44a that is one element of the first relay system 82a is disposed. Yes. Further, in the third optical path OP3 after branching through which the blue light LB passes alone, it is an intermediate position between the first and second conjugate positions C1 and C2, and the first dichroic mirror 41b has a first light exit side. A first condenser lens 46a, which is another element of the relay system 82a, is disposed. The former intermediate field lens 44a has a role of making the principal rays substantially parallel to each other with respect to the light flux (blue light LB) from each point on the first conjugate position C1. The latter first condenser lens 46a is an aspherical lens made of a high refractive index material (for example, heavy flint optical glass) having a refractive index of 1.7 or more, and a light beam from the first conjugate position C1. Is condensed at the second conjugate position C2 to prevent a decrease in light use efficiency due to light diffusion or the like.

  Further, in the branched third optical path OP3, an intermediate field lens 46b, which is one element of the second relay system 82b, is disposed in the vicinity of the upstream side of the optical path facing the second conjugate position C2. Further, in the third optical path OP3 after branching, it is an intermediate position between the second conjugate position C2 and the liquid crystal panel 51c, and on the light emission side of the reflection mirror 42c, there is a second element that is another element of the second relay system 82b. Two condensing lenses 46c are arranged. The former intermediate field lens 46b has a role of making the principal rays substantially parallel to each other with respect to the light flux (blue light LB) from each point on the second conjugate position C2. The second condenser lens 46c is an aspherical lens made of a high refractive index material (for example, heavy flint optical glass) having a refractive index of 1.7 or more, and the light flux from the second conjugate position C2. Is condensed at the position of the B-color liquid crystal panel 51c to prevent a decrease in light use efficiency due to light diffusion or the like.

  At the exit of the color separation light guide 40, emission field lenses 43a, 43b, and 43c for the respective colors are arranged corresponding to the branched optical paths OP1, OP2, and OP3. The exit field lenses 43a, 43b, and 43c for each color receive the partial light beams (the respective color lights LR, LG, and LB) that are emitted from the second lens array 32, pass through the superimposing lens 36, and the like and enter the light modulation unit 50. The incident angle is adjusted so as to have an appropriate convergence or divergence with respect to the system optical axis SA on the irradiated areas of the liquid crystal panels 51a, 51b, 51c constituting the liquid crystal light valves 50a, 50b, 50c. Yes. The effective diameter D1 of the exit field lenses 43a, 43b, 43c is substantially equal to the effective diameter D0 of the homogenizing optical system 30. The effective diameter D1 of the emission field lenses 43a, 43b, and 43c is substantially equal to the effective diameters D2, D3, and D4 of the intermediate field lenses 44a, 45b, and 46b in the color separation light guide 40.

  The light modulation unit 50 is a three-color illumination light that is separated from the illumination light LF, that is, three light modulation devices that are illuminated by the red light LR, the green light LG, and the blue light LB. Three liquid crystal light valves 50a, 50b, and 50c on which LR, LG, and LB respectively enter are provided. The first liquid crystal light valve 50a, which is the first light modulation device, includes a liquid crystal panel 51a for red light LR disposed at the center, an incident-side polarizing filter 52a disposed upstream of the optical path, and an optical path. A downstream exit side polarizing filter 53a. A second liquid crystal light valve 50b, which is a second light modulation device, includes a liquid crystal panel 51b for green light LG disposed in the center, an incident-side polarization filter 52b disposed upstream of the light path, and an optical path. And a downstream exit side polarization filter 53b. A third liquid crystal light valve 50c, which is a third light modulation device, includes a liquid crystal panel 51c for blue light LB disposed in the center, an incident-side polarization filter 52c disposed upstream of the light path, and an optical path. A downstream exit side polarizing filter 53c. Each color light LR, LG, LB incident on each of the liquid crystal light valves 50a, 50b, 50c is a pixel unit in accordance with a drive signal or a control signal input as an electrical signal to each of the liquid crystal light valves 50a, 50b, 50c. The intensity is modulated with. Here, each of the liquid crystal panels 51a, 51b, and 51c is a transmissive liquid crystal panel, and a description thereof is omitted. However, the liquid crystal panels 51a, 51b, and 51c include a light-transmitting incident-side substrate having a transparent electrode and the like, a pixel electrode, and the like. A light-transmissive driving substrate; and a liquid crystal layer hermetically sealed between the incident-side substrate and the driving substrate.

  The color synthesizing unit 60 is a cross dichroic prism for synthesizing a color image, and includes a first dichroic film 61 for reflecting R light and a second dichroic film 62 for reflecting B light in a plane. It is arranged in a visual X shape. The color composition unit 60 causes the red light LR from the liquid crystal light valve 50a to be incident from the first light incident surface 60a, reflected by the first dichroic film 61 as an anti-slope, and from the light emitting surface 60d on the right side in the traveling direction. Let it fire. In addition, the color composition unit 60 causes the green light LG from the liquid crystal light valve 50b to enter from the second light incident surface 60b, travel straight through both the dichroic films 61 and 62, and emit the light from the light emitting surface 60d. Further, the color synthesizing unit 60 causes the blue light LB from the liquid crystal light valve 50c to be incident from the third light incident surface 60c, reflected by the second dichroic film 62 as an anti-slope, and the light emitting surface 60d on the left side in the traveling direction. Let it be injected from.

  Here, the number of reflections in each of the optical paths OP1, OP2, and OP3 from the color separation light guide unit 40 to the color synthesis unit 60 will be considered. In the first optical path OP1, the red light LR is reflected once by the first dichroic film 61 and is mirror-inverted left and right. In the second optical path OP2, the green light LG is reflected a total of three times by the first dichroic mirror 41a and the reflection mirrors 42a and 42b, and is mirror-inverted left and right. In the third optical path OP3, the blue light LB is reflected a total of five times by the first and second dichroic mirrors 41a and 41b, the reflecting mirrors 42c and 42d, and the second dichroic film 62, and is mirror-inverted left and right. Therefore, the difference between the number of times the optical path is bent due to reflection in the first optical path OP1 and the number of times the optical path is bent in the second optical path OP2 is an even number. Further, the difference between the number of times the optical path is bent due to reflection in the first optical path OP1 and the number of times the optical path is bent in the third optical path OP3 is also an even number. That is, the result of mirror image reflection in each of the optical paths OP1, OP2, and OP3 is the same on the light exit surface 60d of the color composition unit 60, and inversion between colors is prevented.

  The projection optical system 70 projects the image light combined by the color combining unit 60 as a projection lens as a color image on a screen (not shown).

  As is clear from the above description, according to the projector 100 of the present embodiment, the color separation light guide unit 40 directly receives the red light LR as the first color light separated by the first dichroic mirror 41a as the separation mirror. Therefore, the distance from the illuminating unit 10 to the first liquid crystal light valve 50a can be shortened, and the size of the illuminating unit 10 reduces the size of the projector 100. The size can be reduced.

  In the projector 100 according to the present embodiment, the color separation light guide unit 40 transfers the green light LG as the second color light separated by the first dichroic mirror 41a as the separation mirror by projecting it twice. The double relay optical system 81 and the second double relay optical system 82 that transfers the blue light LB as the third color light by projecting it twice are provided on the light exit surface 60d of the color combining unit 60. If the effects of the first and second dichroic mirrors 41a and 41b, the reflection mirrors 42a, 42b, 42c and 42d, and the dichroic films 61 and 62 are ignored, green light LG and blue light as the second and third color lights The LB image can be erected with respect to the image of the red light LR as the first color light. Furthermore, the difference between the number of times of bending of the optical path due to reflection regarding the red light LR as the first color light and the number of times of bending of the optical path due to reflection regarding the green light LG and the blue light LB as the second and third color lights is an even number. Therefore, it is possible to prevent the images of the green light LG and the blue light LB from being mirror-inverted with respect to the image of the red light LR. That is, the three liquid crystal light valves 50a, 50b, and 50c can be illuminated with their upper, lower, left, and right aligned, and the image light from these can be combined with their upper, lower, left, and right aligned. As a result, luminance unevenness and color unevenness of the projected image can be reduced.

  Furthermore, according to the projector described above, the red light LR is separated by being transmitted by the first dichroic mirror 41a, and is synthesized by being folded by the first dichroic film 61 of the color synthesizing unit 60. The system optical axis SA in the projection optical system 70 is orthogonal. For this reason, even if the inclination angle of the projection optical system 70 is adjusted and changed, the system optical axis SA in the illumination unit 10 can be kept horizontal, and the operation of the illumination unit 10 can be stabilized to prevent a temperature rise or the like. Can do.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  In the projector 100 of the above embodiment, the first condenser lenses 45a and 46a and the second condenser lenses 45c and 46c are configured by one lens, but these condenser lenses are configured by two or more lenses. You can also. At this time, any one or more surfaces of any of the lenses can be aspherical, but all can be spherical.

  In the projector 100 of the above embodiment, since the light source lamp unit 20 as a light source is formed of a high-pressure mercury lamp or the like, the red light LR having the weakest light intensity is guided to the first optical path OP1 that travels straight and has little loss. However, when the color light having a different light source and the weakest light intensity is the green light LG or the blue light LB, these color lights can be guided to the first optical path OP1.

  In the projector 100 of the above embodiment, the effective diameter D1 of the emission field lenses 43a, 43b, and 43c is substantially equal to the effective diameter D0 of the uniformizing optical system 30, but the effective diameter D1 of the emission field lenses 43a, 43b, and 43c. Can be made larger than the effective diameter D0 of the homogenizing optical system 30.

  In the projector 100 of the above embodiment, a pair of lens arrays 31 and 32 is used to divide the light from the light source lamp unit 20 into a plurality of partial light beams. However, a rod integrator is used instead of such a lens array. be able to.

  In the projector 100 of the above embodiment, the polarization conversion member 34 that converts the light from the light source lamp unit 20 or the like into polarized light in a specific direction is used. However, the present invention does not use such a polarization conversion member 34. It is also applicable to.

  Moreover, as a projector, there are a front projection type projector that projects an image from the direction of observing the projection surface and a rear projection type projector that projects an image from the side opposite to the direction of observing the projection surface. The configuration of the projector 100 shown in 1 can be applied to any of them.

  In the above embodiment, only the example of the projector 100 using the three liquid crystal light valves 50a, 50b, and 50c has been described. However, the present invention can also be applied to a projector using two light valves.

DESCRIPTION OF SYMBOLS 10 ... Illuminating part, 20 ... Light source lamp unit, 21a ... Lamp part, 30 ... Uniformation optical system 31, 32 ... Lens array, 34 ... Polarization conversion member, 36 ... Superimposing lens, 40 ... Color separation light guide part, 41a , 41b ... Dichroic mirror, 42a, 42b, 42c, 42d ... Reflection mirror, 43a, 43b, 43c ... Emission field lens, 44a, 45b, 46b ... Intermediate field lens, 45a, 45c, 46a, 46c ... Condensing lens, 50 Light modulator, 50a, 50b, 50c ... Liquid crystal light valve, 51a, 51b, 51c ... Liquid crystal panel, 52a, 52b, 52c ... Incident side polarization filter, 53a, 53b, 53c ... Emission side polarization filter, 60 ... Color composition 60a: first light incident surface, 60b: second light incident surface, 60c: third Incident surface, 60d ... light exit surface, 61 ... first dichroic film, 62 ... second dichroic film, 70 ... projection optical system, 81 ... second double relay optical system, 81a ... first relay system, 81b ... second Relay system, 82 ... first double relay optical system, 82a ... first relay system, 82b ... second relay system, 100 ... projector, C1 ... first conjugate position, C2 ... second conjugate position, LF ... illumination light, LB ... Blue light, LG ... Green light, LR ... Red light, LR, LG, LB ... Color light, illumination light, OP1, OP2, OP3 ... Optical path, SA ... System optical axis

Claims (6)

An illumination unit including a light source;
A color separation light guide having a separation mirror that separates first color light having a predetermined wavelength from light emitted from the illumination unit from second color light having another wavelength by transmission;
A light modulation unit comprising: a first light modulation device that modulates the separated first color light; and a second light modulation device that modulates the separated second color light;
A color combining unit that combines the modulated first color light and the second color light to form image light;
A projection optical system that projects the formed image light,
The color separation light guide unit causes the first color light separated by the separation mirror to directly enter the first light modulation device, and projects the second color light separated by the separation mirror twice. Have double relay optics to transfer by
The color combining unit includes a first light incident surface on which the first color light that has passed through the first light modulation device is incident, and a second light incident surface on which the second color light that has passed through the second light modulation device is incident. And a reflecting surface that reflects the first color light incident from the first light incident surface, and a light exit surface that faces the projection optical system,
In the projector from the color separation light guide unit to the color synthesis unit, a difference between the number of times of bending of the optical path due to reflection regarding the first color light and the number of times of bending of the optical path due to reflection regarding the second color light is an even number. . The illumination unit includes a homogenizing optical system that is disposed between the light source and the color separation light guide unit and uniformizes the illuminance of light emitted from the light source in a plane orthogonal to the system optical axis. ,
The color separation light guide unit includes an emission field lens that adjusts a state of the first color light that is disposed between the color separation light guide unit and the first light modulation device and passes therethrough,
The projector according to claim 1, wherein an effective diameter of the uniformizing optical system is substantially equal to an effective diameter of the emission field lens. The double relay optical system forms a first intermediate field lens disposed in the vicinity of a first conjugate position corresponding to the position of the first light modulator, and an image of the first conjugate position at a second conjugate position. A first relay system having a first condensing lens, a second intermediate field lens disposed in the vicinity of the second conjugate position, and an image of the second conjugate position at the position of the second light modulator. A second relay system having a second condenser lens for imaging,
The projector according to claim 2, wherein an effective diameter of the first intermediate field lens and the second intermediate field lens is substantially equal to an effective diameter of the emission field lens.   The projector according to any one of claims 1 to 3, wherein the first condenser lens and the second condenser lens are formed of heavy flint optical glass. The color separation light guide unit includes a second separation mirror that separates third color light having a wavelength different from that of the first color light and the second color light from light emitted from the illumination unit, and the second separation. A second double relay optical system for transferring the third color light separated by the mirror by projecting it twice.
The light modulation unit further includes a third light modulation device that modulates the separated third color light,
The difference between the number of times the optical path is bent due to reflection relating to the first color light and the number of times the optical path is bent due to reflection relating to the third color light is an even number from the color separation light guide unit to the color combining unit. The projector according to any one of claims 1 to 4.   The projector according to any one of claims 1 to 5, wherein the first color light is light having a wavelength with which light intensity emitted from the light source is relatively weak.

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