JP2006084618A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve high-luminance, natural white balance, while minimizing a signal process using luminance value. <P>SOLUTION: Rays of color light LB, LR, and LG, namely image light modulated by liquid crystal panels 51b, 51r, and 51g, are composited by a cross dichroic prism 60. Then, the composed ray of light is projected onto a screen via a projecting lens 70. In the projector 10, the illuminance of green light LG in the illuminated area of the liquid crystal panel 51g can be varied, by adjusting the aperture of a variable diaphragm 90 disposed on a third optical path OP3. In other words, without using an ND filter that is susceptible to heat, liquid crystal panels 51b, 51r, and 51g can be illuminated having a desired balance between them. As a result, the white balance of a color image projected to the screen by the projecting lens 70, after the rays of image light have passed through the liquid crystal panels 51b, 51r, and 51g and composed can be easily adjusted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projector that projects an image using a light modulation device such as a liquid crystal panel.

  As an illumination device for a liquid crystal panel incorporated in a conventional projector, light source light from a white light source is separated into three colors, a relay optical system is disposed on the red illumination optical path, and the optical path lengths for the remaining green and blue There are those that compensate for the difference (see Patent Documents 1, 2, and 3).

  As another lighting device for liquid crystal panels, the light source light from the white light source is separated into three colors, and a relay optical system is arranged on the blue illumination light path, and the difference in optical path length with respect to the remaining two colors is determined. There is something to compensate (see Patent Document 4). In this projector, the incident angle of the illumination light to the blue liquid crystal panel is limited by arranging an attenuation plate on the incident side or emission side of the central lens among the three lenses constituting the relay optical system. Thus, the deterioration of contrast caused by the viewing angle is suppressed.

As another illumination device for a liquid crystal panel, light source light from a white light source is separated into three colors, and light guide means such as a relay optical system is disposed on the green illumination light path, and the remaining two colors are provided. There is one that compensates for the difference in optical path length (see Patent Document 5).
Japanese Patent Laid-Open No. 10-171045 JP 2003-287804 A JP-A-11-242184 Japanese Patent Laid-Open No. 2001-222002 WO94 / 22042

  However, in an illuminating device in which a relay optical system is arranged on the red illumination optical path, red is relatively weak compared to other colors due to the use of, for example, a high-pressure mercury lamp as a light source, and white balance is reduced. It may not be possible to adjust properly. In such a case, white balance can be achieved by signal processing for adjusting the luminance value of the image signal to be input to the liquid crystal panel, but there is a problem that the brightness and contrast of the image are lowered.

  In addition, an illumination device provided with an attenuation plate in the blue light path can prevent a decrease in contrast of the blue image and the entire image, but it can positively compensate for the white balance bias caused by the light emission characteristics of a high-pressure mercury lamp or the like. It cannot be resolved.

  Also, in an illuminating device in which a relay optical system is arranged on the green illumination optical path, the white balance often varies greatly from product to product due to light emission characteristics such as a high-pressure mercury lamp, and the image signal to be input to the liquid crystal panel Signal processing for greatly adjusting the luminance value of the.

  Accordingly, the present invention provides a high-brightness and natural white balance while minimizing signal processing using luminance values even when using a lamp light source having a certain tendency in spectral characteristics such as a high-pressure mercury lamp. An object of the present invention is to provide a projector that can achieve the above.

  In order to solve the above problems, a projector according to the present invention includes: (a) a lighting device including a light source device having a lamp body that forms a light emitting unit; and a concave mirror that reflects light emitted from the lamp body; (B) A color separation optical system that divides blue light, red light, and green light from illumination light emitted from the illumination device and guides blue light, red light, and green light to the first to third optical paths, respectively. And (c) first to third light modulation devices respectively disposed on the first to third optical paths and illuminated by the blue light, red light, and green light, respectively. Here, (d) the distance from the illumination device to the third light modulation device is longer than the distance from the illumination device to the first light modulation device and the distance from the illumination device to the second light modulation device. The three optical paths include a first lens disposed on the light incident side, a second lens disposed on the light exit side, and a third lens disposed between the first and second lenses. (F) A variable stop capable of partially blocking green light is disposed near the incident side or the exit side of the third lens.

  In the projector described above, the variable stop is disposed near the incident side or the exit side of the third lens, and the green light can be partially blocked. Therefore, the third light modulation can be performed by adjusting the variable stop. The illuminance on the apparatus can be adjusted to almost the target value, and the target white balance can be easily achieved without lowering the brightness and contrast of the image. In the projector described above, the relay optical system is arranged on the third light path for green light, so that loss of green light is likely to occur, but a natural white balance is achieved with a lamp light source with a large amount of green light. It will have a rather positive effect on the above. In this case, since the green light has a relatively high visibility, it has a large effect on the white balance. However, since the variable aperture is provided on the third optical path, the illuminance of the green light on the third light modulation device is reduced. By adjusting, the contrast can be adjusted accurately and appropriately.

  In a specific aspect or embodiment of the present invention, an image of a light emitting part (hereinafter referred to as “light source image”) is formed in the vicinity of the third lens. In this case, since the green light can be partially blocked at a position where the light source image becomes clearer or in the vicinity thereof, the uniformity of the illumination light incident on the third light modulation device can be further improved.

  In another specific aspect of the present invention, the variable stop has a variable aperture, and the light shielding amount is adjusted by changing the beam cross section of the green light guided to the third optical path. In this case, simple light quantity adjustment is possible.

  In another specific aspect of the present invention, the variable stop includes a pair of light shielding plates arranged perpendicular to the optical axis of green light, and the pair of light shielding plates in a direction perpendicular to the optical axis of green light. And a drive member for moving the pair of light shielding plates along the guide member. In this case, it is possible to precisely adjust the light amount of the green light with a simple mechanism.

  In another specific aspect of the present invention, the variable aperture is integrated and fixed to the holder of the third lens. In this case, it becomes easy to incorporate the variable aperture, contributing to space saving.

  In another specific aspect of the present invention, the illumination device divides the light emitted from the light source device to form a plurality of wavefront split lights, and superimposes the wavefront split lights to thereby form the first to the first. A uniform optical system that uniformly illuminates the third light modulation device is provided. In this case, a large number of light source images corresponding to a plurality of wavefront split lights are formed in the vicinity of the third lens. By cutting a part of such a large number of light source images by the operation of the variable aperture, the first The illuminance can be adjusted efficiently in the three-light modulation device.

  The homogenizing optical system can be configured to include two fly's eye optical systems and prismatic rods (a hollow rod combining four mirrors and a solid rod made of prismatic glass). .

  In another specific aspect of the present invention, a light combining optical system that combines image light of each color obtained by modulating blue light, red light, and green light by the first to third light modulation devices, respectively, A projection optical system that projects the combined light emitted from the light combining optical system. In this case, the color image synthesized by the light synthesizing optical system can be projected on the screen at a desired size by the projection optical system.

  Hereinafter, the best mode for carrying out the present invention will be described. In the following description, an axis parallel to the traveling direction of light is referred to as a Z axis, and two axes orthogonal to this are referred to as an X axis and a Y axis. In addition, the direction opposite to the light traveling direction is defined as a positive direction (+ Z direction), and the light traveling direction is defined as a negative direction (−Z direction).

  FIG. 1 is a diagram illustrating a projector according to an embodiment of the invention. The projector 10 includes a light source device 20 that generates light source light, a uniformizing optical system 30 that uniformizes illumination light from the light source device 20, and illumination light that has passed through the uniformizing optical system 30 in three colors of red, green, and blue. A color separation optical system 40 that divides into colors, a light modulation unit 50 that is illuminated by illumination light of each color emitted from the color separation optical system 40, and a cross dichroic prism that combines modulated light of each color from the light modulation unit 50 60 and a projection lens 70 that projects image light that has passed through the cross dichroic prism 60 onto a screen (not shown). Among the above, the light source device 20 and the uniformizing optical system 30 function as an illumination device that emits illumination light.

  Here, the light source device 20 includes a lamp main body 21 that forms a substantially dot-like light emitting portion, and a parabolic concave mirror 22 that collimates the light source light emitted from the lamp main body 21. Among these, the lamp body 21 is composed of, for example, a high-pressure mercury lamp, and emits substantially white light source light. Further, the concave mirror 22 reflects the light beam emitted from the lamp body 21 and causes it to enter the uniformizing optical system 30 as a parallel light beam. Instead of the parabolic concave mirror 22, a concave mirror that is not parabolic, such as a spherical surface or an elliptical surface, may be used. When such a concave mirror is used, a parallel light beam can be emitted from the light source device 20 by arranging a parallelizing lens between the concave mirror 22 and the homogenizing optical system 30.

  The homogenizing optical system 30 includes a pair of fly's eye optical systems 31, 32, a superimposing lens 33 for superimposing wavefront split light, and a polarization conversion member 34 for converting illumination light into a predetermined polarization component. . The pair of fly-eye optical systems 31 and 32 includes a plurality of element lenses arranged in a matrix. The element lenses divide the illumination light from the light source device 20 and individually collect and divide the illumination light. The polarization conversion member 34 converts the illumination light emitted from the fly-eye optical systems 31 and 32 into one type of polarized light (for example, only the S-polarized component perpendicular to the paper surface of FIG. 1) and supplies it to the next-stage optical system. The superimposing lens 33 allows the illumination light having passed through the polarization conversion member 34 to appropriately converge as a whole, and enables superimposing illumination on the light modulation devices of the respective colors provided in the light modulation unit 50. In other words, the illumination light that has passed through both the fly-eye optical systems 31 and 32 and the superimposing lens 33 passes through the color separation optical system 40 described in detail below, and the light modulation device for each color constituting the light modulation unit 50, that is, the liquid crystal for each color. The image forming areas of the panels 51b, 51r, and 51g are uniformly superimposed and illuminated.

The color separation optical system 40 includes first and second dichroic mirrors 41a and 41b, reflection mirrors 42a, 42b, and 42c, field lenses 43r and 43b, and first to third lenses 45a, 45b, and 45c. The first dichroic mirror 41a reflects the blue light LB among the three colors of red, blue, and green (R, G, and B) and transmits the green light LG and the red light LR. The second dichroic mirror 41b reflects the red light LR out of the incident green light LG and red light LR and transmits the green light LG. In the color separation optical system 40, the illumination light emitted from the light source device 20 through the uniformizing optical system 30 first enters the first dichroic mirror 41a. The blue light LB reflected by the first dichroic mirror 41a is guided to the first optical path OP1 and enters the field lens 43b for adjusting the incident angle via the reflection mirror 42a. Further, the red light LR transmitted through the first dichroic mirror 41a and reflected by the second dichroic mirror 41b is guided to the second optical path OP2 and enters the field lens 43r. Further, the green light LG that has passed through the second dichroic mirror 41b is guided to the third optical path OP3, and passes through the lenses 45a, 45b, and 45c via the reflection mirrors 42b and 42c. The reflection mirrors 42b and 42c and the lenses 45a, 45b, and 45c are disposed in the third green light path OP3 having the longest light path distance from the light source device 20 to the liquid crystal panels 51b, 51r, and 51g of the respective colors. This relay optical system transmits the image of the first lens 45a almost directly to the third lens 45c via the second lens 45b, thereby preventing a decrease in light use efficiency due to light diffusion or the like. is doing.
A variable stop 90 is disposed in front of the central lens 45b in the vicinity of the lens 45b. As will be described in detail later, the variable stop 90 has a role of adjusting the amount of illumination of the green light LG that passes through the third optical path OP3.

  The light modulator 50 includes three liquid crystal panels 51b, 51r, and 51g on which the three colors of illumination light LB, LR, and LG are incident, and three sets of polarized light disposed so as to sandwich the liquid crystal panels 51b, 51r, and 51g. Filters 52b, 52r, and 52g. Here, for example, the blue light LB liquid crystal panel 51b and the pair of polarizing filters 52b and 52b sandwiching the liquid crystal panel 51b constitute a liquid crystal light valve for two-dimensionally modulating the illumination light. Similarly, the liquid crystal panel 51r for red light LR and the corresponding polarizing filters 52r and 52r also constitute a liquid crystal light valve, and the liquid crystal panel 51g for green light LG and the polarizing filters 52g and 52g also form a liquid crystal light valve. Constitute.

  In the light modulation unit 50, the blue light LB guided to the first optical path OP1 enters the irradiated region of the liquid crystal panel 51b via the field lens 43b. The red light LR guided to the second optical path OP2 enters the irradiated region of the liquid crystal panel 51r through the field lens 43r. The green light LG guided to the third optical path OP3 enters the irradiated area of the liquid crystal panel 51g via the lenses 45a, 45b, and 45c. Each of the liquid crystal panels 51b, 51r, and 51g is a non-luminous and transmissive light modulation device for changing the spatial distribution of the polarization direction of incident illumination light, and is incident on each of the liquid crystal panels 51b, 51r, and 51g. The polarization state of each color light LB, LR, LG is adjusted in units of pixels in accordance with drive signals or image signals input as electrical signals to the liquid crystal panels 51b, 51r, 51g. At that time, the polarization filters 52b, 52r, and 52g adjust the polarization direction of the illumination light incident on the liquid crystal panels 51b, 51r, and 51g, and at the same time, emit light from the light emitted from the liquid crystal panels 51b, 51r, and 51g. The modulated light in the polarization direction is extracted.

  The cross dichroic prism 60 is a photosynthetic optical system, and is a state in which a reflective film (for example, dielectric multilayer film) 61 for reflecting blue light and a reflective film (for example, dielectric multilayer film) 62 for reflecting green light are orthogonal to each other. It is built in. The cross dichroic prism 60 reflects the blue light LB from the liquid crystal panel 51b by the reflection film 61 and emits it to the right in the traveling direction, and the red light LR from the liquid crystal panel 51r goes straight and exits through the reflection films 61 and 62. The green light LG from the liquid crystal panel 51g is reflected by the reflective film 62 and emitted to the left in the traveling direction. The image light combined by the cross dichroic prism 60 in this way is projected as a color image on a screen (not shown) at an appropriate magnification through a projection lens 70 which is a projection optical system.

  FIG. 2 is a perspective view illustrating specific fixing of the color separation optical system 40, the light modulation unit 50, the cross dichroic prism 60, and the like. On the base member 80, dichroic mirrors 41a and 41b, lenses 45a, 45b and 45c, reflection mirrors 42a, 42b and 42c and the like constituting the color separation optical system 40 are fixed in an aligned state. A mount member 81 is fixed to the base member 80, and the projection lens 70 is aligned with the prism unit 85 including the cross dichroic prism 60, the light modulator 50, and the like via the mount member 81. It is supported in the state. The middle lens 45b fixed to the base member 80 is attached to the base member 80 as a lens unit 190 integrated with the variable diaphragm 90, as will be described in detail later.

  FIG. 3 is a development view for explaining the state of the light beam in the third optical path OP3 of the projector 10 shown in FIG. It is a figure to do. Among these, FIG. 3A shows an initial standard state, and FIG. 3B shows a state in which the variable diaphragm 90 arranged in the relay optical system is operated. In the relay optical system, the reflection mirrors 42b and 42c (see FIG. 1) are omitted for the sake of convenience in explaining the imaging state. For convenience, only a part of the light flux is shown in FIGS. 3 (a) and 3 (b).

  In the state shown in FIG. 3A, the homogenizing optical system 30 divides the light emitted from the light source device 20 by the first fly-eye optical system 31 to form a plurality of wavefront-divided lights 30a. A plurality of condensed images are formed near the system 32. This condensed image is an image (light source image) of the light emitting part formed on the lamp main body 21 shown in FIG. Each element lens constituting the second fly's eye optical system 32 relays a plurality of wavefront split lights 30a, and the image formed at the position of the element lens of the first fly's eye optical system 31 is near the position of the lens 45a. The image is formed with. Further, the plurality of wavefront split lights 30a are once superimposed in the vicinity of the position of the lens 45a by the superimposing lens 33. The plurality of wavefront split lights 30a form a plurality of condensed images (light source images) in the vicinity of the lens 45b by the action of the lens 45a. Furthermore, after the plurality of wavefront split lights 30a pass through the lens 45c, they are superimposed again near the position of the liquid crystal panel 51g. In this manner, the irradiated region corresponding to the liquid crystal panel 51g is uniformly illuminated by the green light LG emitted from the uniform optical system 30 and passing through the lenses 45a, 45b, and 45c.

  On the other hand, in the state shown in FIG. 3B as well, as in the state shown in FIG. 3A, the green light LG emitted from the uniformizing optical system 30 and passed through the lenses 45a, 45b, and 45c corresponds to the liquid crystal panel 51g. The illuminated area is illuminated uniformly. However, the pair of shielding plates 91 and 92 constituting the variable stop 90 provided in front of the central lens 45b is moved by an equal distance in the direction of the optical axis OA so as to be close to each other while maintaining a state perpendicular to the optical axis OA. Thus, the opening of the third optical path OP3 is narrowed. By such aperture adjustment, the light beam of the green light LG is partially blocked on the peripheral side, and the irradiated area of the liquid crystal panel 51g is illuminated with a low illuminance corresponding to the aperture adjustment of the variable stop 90. At this time, since the variable diaphragm 90 is disposed at a position close to the plurality of light source images formed in the vicinity of the lens 45b, the illuminance distribution of the green light LG incident on the liquid crystal panel 51g is maintained substantially uniform.

  In general, since the green light LG has a relatively high visibility, it has a great influence on the white balance. Further, the light source device 20 including the lamp body 21 made of a high-pressure mercury lamp is likely to vary in the relative light amount of the green light LG. In this embodiment, since the light amount of the green light LG is adjusted using the aperture adjustment by the variable diaphragm 90, the white balance of the projector 10 can be adjusted efficiently. In the case of a high-pressure mercury lamp, since the amount of green light LG tends to be larger than the amount of blue light LB or red light LR, even if some light loss occurs due to the opening adjustment of the variable aperture 90, Does not work against white balance adjustment. In addition to the variation in the relative light quantity of the lamp, the cause of the influence on the white balance is also the variation in the characteristics of the liquid crystal panel 51g and the variation in the wavelength selection characteristics of the dichroic mirrors 41a and 41b and the cross dichroic prism 60. However, according to the projector of the present embodiment, the white balance of the projector 10 can be set to almost the target value regardless of various factors that cause variations in the light amount of the green light LG. It doesn't sacrifice pod contrast.

  In the above description, the variable diaphragm 90 is disposed in front of the central lens 45b. However, for example, the variable diaphragm 90 may be disposed in the rear of the central lens 45b. Also in this case, the variable diaphragm 90 is disposed near the light source image, and by adjusting the aperture of the variable diaphragm 90, the luminous flux of the green light LG is appropriately blocked, and the green light LG incident on the irradiated region of the liquid crystal panel 51g Increase / decrease adjustment is performed with the light amount kept uniform.

  FIG. 4 is a diagram for explaining the role of the variable diaphragm 90 for adjusting the amount of light shown in FIGS. FIG. 4A is a diagram for conceptually explaining the distribution of the green light LG at the position of the variable diaphragm 90, and FIG. 4B is a diagram illustrating a variable aperture by operating the variable diaphragm 90 for light amount adjustment. Indicates the case of narrowing down.

  As shown in FIG. 4A, at the position where the variable aperture 90 is disposed, that is, at the position close to the central lens 45b on the third optical path OP3, as described above, the fly-eye optical system of FIG. A plurality of light source images SSP are formed in a matrix-like arrangement corresponding to the arrangement of the element lenses constituting 31 and 32. Further, as shown in FIG. 4B, when aperture adjustment is performed by operating the variable stop 90, the aperture AP of the third optical path OP3 includes all of one or more columns on both ends of the light source image SSP. Or a part is removed. As a result, the amount of the green light LG passing through the third optical path OP3 is reduced, but the illuminance distribution of the green light LG in the irradiated region of the liquid crystal panel 51g is uniform only by reducing the number of the light source images SSP. Maintained.

  When the aperture stop AP is narrowed by operating the variable stop 90, the shielding plate 91, 92 is moved stepwise so that the light source image SSP is removed from the end side in units of columns. This is advantageous in ensuring the uniformity of the green light LG. At this time, the illuminance of the green light LG in the irradiated region of the liquid crystal panel 51g changes in a stepped manner, and fine adjustment of the illuminance to compensate for the illuminance is performed by electric signal processing on the luminance value of the image signal supplied to the liquid crystal panel 51g It becomes possible by doing.

  FIG. 5 is a perspective view for explaining the structure of the lens unit 190 shown in FIG. This lens unit 190 includes a lens holder 193 that holds the lens 45b, and a shielding plate holder 194 that holds a pair of shielding plates 91 and 92 constituting the variable diaphragm 90 so as to be slidable.

  On the side wall of the former lens holder 193, a pair of convex portions 193a and 193b to be fitted into slot portions provided at appropriate positions of the base member 80 (see FIG. 2) are formed to face each other. It can be accurately fixed on the three optical paths OP3. A pair of claws 193c and 193d are erected on the upper surface of the lens holder 193 for the convenience of holding the lens holder 193 when the lens holder 193 is attached or detached.

  The latter shielding plate holder 194 includes a seat plate 194 a fixed to the lens holder 193, a guide plate 194 b that guides the upper ends of the shielding plates 91 and 92, and a drive screw 194 c that moves the lower ends of the shielding plates 91 and 92. Prepare. Here, the seat plate 194a and the guide plate 194b function as guide members and engage the upper ends of the shielding plates 91 and 92 to allow the shielding plates 91 and 92 to slide in the ± X directions. A pair of support plate portions 194d and 194f erected on the lower end of the seat plate 194a supports the drive screw 194c so as to be rotatable in its axial direction. Here, the drive screw 194c functions as a drive member for opening and closing the shielding plates 91 and 92 in cooperation with the support plate portions 194d and 194f. Annular grooves GR1 and GR2 are formed around the head 194j and the link 194k provided on the drive screw 194c, respectively. Both grooves GR1 and GR2 are formed in U-shaped grooves of both support plate portions 194d and 194f. The drive screws 194c are not loosened by the support plate portions 194d and 194f. Screw portions SC1 and SC2 extend on the right side (X direction) of the head 194j and the link 194k, respectively, and are drilled in a pair of support plate portions 91g and 92g erected at the lower ends of the shielding plates 91 and 92. Screwed into the opening. Here, the screw threads SC1 and SC2 are threaded in the opposite directions on the outer periphery thereof, and the shielding plates 91 and 92 come close to each other and move away with the rotation of the drive screw 194c. ing. At this time, the drive screws 194c are inserted through the openings formed in the guide plates 91h and 92h so that the posture of the shielding plates 91 and 92 extending in the Y direction can be maintained.

  When the drive screw 194c is rotated, for example, clockwise to bring the shielding plates 91 and 92 close to each other, the standing plate 194m and the guide plate 91h cooperate with each other to move the shielding plate 91 in the + X direction. The link 194k and the support plate portion 92g also function as a limit when the shielding plate 92 moves in the −X direction in cooperation with each other. In addition, when the drive screw 194c is rotated, for example, counterclockwise to rotate the shield plates 91 and 92 away from each other, the head 194j and the support plate portion 91g cooperate with each other so that the shield plate 91 is -X. The standing plate 194n and the guide plate 92h also function as a limit when the shielding plate 92 moves in the + X direction in cooperation with each other. As described above, both the shielding plates 91 and 92 can be moved synchronously within a certain range, and the aperture AP of the variable diaphragm 90 can be adjusted freely.

  Hereinafter, the operation of the projector 10 according to the present embodiment will be described. The illumination light from the light source device 20 is subjected to color division by the first and second dichroic mirrors 41 a and 41 b provided in the color separation optical system 40 after the polarization direction is aligned through the uniformizing optical system 30 and correspondingly. The light beams enter the liquid crystal panels 51b, 51r, and 51g as the color lights LB, LR, and LG, respectively. Each liquid crystal panel 51b, 51r, 51g is modulated by an image signal from the outside and has a two-dimensional refractive index distribution, and modulates each color light LB, LR, LG in a two-dimensional space in units of pixels. As described above, the color lights LB, LR, LG modulated by the liquid crystal panels 51b, 51r, 51g, that is, the image light, are combined by the cross dichroic prism 60 and then incident on the projection lens 70. The image light incident on the projection lens 70 is projected on a screen (not shown). In the projector 10, the green light in the irradiated area of the liquid crystal panel 51g is adjusted by adjusting the aperture of the variable diaphragm 90 disposed on the third optical path OP3 during or after the assembly of the color separation optical system 40 and the like. The illuminance of LG can be changed as appropriate. That is, each liquid crystal panel 51b, 51r, 51g can be illuminated with a desired balance without using an ND filter that is susceptible to thermal influence. Therefore, the white balance of the color image synthesized through the liquid crystal panels 51b, 51r and 51g and projected onto the screen by the projection lens 70 can be easily adjusted.

  In addition, this invention is not restricted to said embodiment, In the range which does not deviate from the summary, it can implement in a various aspect, For example, the following deformation | transformation is also possible.

  In the projector 10 of the above embodiment, a high-pressure mercury lamp is used as the light source device 20, but other metal halide lamps, rare gas discharge lamps, or the like can be used instead of the high-pressure mercury lamp. Also in this case, the white balance of the illumination light from the lamp light source can be appropriately adjusted by arranging the variable stop 90 on the third light path OP3 for green light and adjusting the opening.

  Further, the structure of the shielding plate holder 194 for driving and fixing the variable stop 90 incorporated in the color separation optical system 40 is not limited to that illustrated in FIG. 5 and can be various. .

  In the above embodiment, the two fly's eye optical systems 31 and 32 are used in order to divide the light from the light source device 20 into a plurality of partial light beams. The present invention can also be applied to a projector that does not use a lens array. Furthermore, the fly-eye optical systems 31 and 32 can be replaced with rod integrators. In this case, the variable stop 90 is disposed adjacent to the lens disposed in the vicinity of the position where the light source image is formed in the relay optical system subsequent to the rod integrator.

  In the projector 10, the polarization conversion member 34 that converts the light from the light source device 20 into a specific direction of polarization is used. However, the present invention can also be applied to a projector that does not use such a polarization conversion member 34. is there.

  In the above embodiment, an example in which the present invention is applied to a transmissive projector has been described. However, the present invention can also be applied to a reflective projector. Here, “transmission type” means that the light valve including the liquid crystal panel is a type that transmits light, and “reflection type” is a type that the light valve reflects light. Means. In the case of a reflection type projector, the light valve can be constituted only by a liquid crystal panel, and a pair of polarizing plates is unnecessary. The light modulation device is not limited to a liquid crystal panel or the like, and may be a light modulation device using a micromirror, for example.

  Further, as the projector, there are a front projector that projects an image from the direction of observing the projection plane and a rear projector that projects an image from the opposite side to the direction of observing the projection plane. The projector configuration shown in FIG. Is applicable to both.

It is a figure explaining the optical system of the projector which concerns on embodiment. It is a perspective view explaining concrete fixation of a color separation optical system, a light modulation part, etc. (A) shows the light beam of the 3rd optical path of a projector, (b) shows the state which operated the variable aperture_diaphragm | restriction. (A) shows the green light distribution at the position closest to the lens, and (b) shows the case where the variable aperture is operated. It is a perspective view explaining the structure of a lens unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Projector, 20 ... Light source device, 30 ... Uniformation optical system 31, 32 ... Fly eye optical system, 34 ... Polarization conversion member, 40 ... Color separation optical system, 41a, 41b ... Dichroic mirror, 42a, 42b, 42c Reflector mirrors 42b, 42c, 45a, 45b, 45c ... Relay optical system, 43r, 43b ... Field lenses, 45a, 45b, 45c ... Lenses constituting the relay lens, 50 ... Light modulators, 51b, 51r, 51g ... Liquid crystal panel, 52b, 52r, 52g ... polarizing filter, 60 ... cross dichroic prism, 70 ... projection lens, 90 ... variable aperture, 91, 92 ... shielding plate, 190 ... lens unit, 193 ... lens holder, 194 ... shielding plate holder 194a ... Seat plate, 194b ... Guide plate, 194c ... Drive screw, 19 j ... head, 194k ... link, AP ... opening, LB, LR, LG ... each color light, OA ... optical axis, OP1 ... first optical path, OP2 ... second optical path, OP3 ... third optical path

Claims (7)

An illuminating device including a light source device having a lamp main body forming a light emitting unit and a concave mirror that reflects light emitted from the lamp main body;
A color separation optical system that branches blue light, red light, and green light from the illumination light emitted from the illumination device and guides the blue light, red light, and green light to first to third optical paths, respectively; ,
First to third light modulators respectively disposed on the first to third optical paths and illuminated by the blue light, red light, and green light, respectively;
A projector comprising:
The distance from the illumination device to the third light modulation device is longer than the distance from the illumination device to the first light modulation device and the distance from the illumination device to the second light modulation device,
The third optical path includes a first lens disposed on the light incident side, a second lens disposed on the light exit side, and a third lens disposed between the first and second lenses. A relay optical system having a lens,
A projector in which a variable stop capable of partially shielding the green light is disposed in the vicinity of an incident side or an emission side of the third lens.   The projector according to claim 1, wherein an image of the light emitting unit is formed in the vicinity of the third lens.   The variable aperture has a variable aperture, and adjusts a light shielding amount by changing a beam cross section of the green light guided to the third optical path. The projector according to one item.   The variable diaphragm includes a pair of light shielding plates arranged perpendicular to the optical axis of the green light, and a guide for holding the pair of light shielding plates so as to be slidable in a direction perpendicular to the optical axis of the green light. The projector according to claim 1, further comprising: a member; and a driving member that moves the pair of light shielding plates along the guide member.   The projector according to any one of claims 1 to 4, wherein the variable aperture is integrated and fixed to a holder of the third lens.   The illumination device divides the light emitted from the light source device to form a plurality of wavefront split lights, and uniformly illuminates the first to third light modulation devices by superimposing the wavefront split lights. The projector according to claim 1, further comprising: an optical system. A light combining optical system that combines image light of each color obtained by modulating the blue light, red light, and green light by the first to third light modulation devices, and combined light emitted from the light combining optical system The projector according to claim 1, further comprising: a projection optical system that projects

Images