JP2004038086A - projector - Google Patents

Abstract

An object of the present invention is to easily improve light use efficiency in a projector including a rod integrator.
A light source device that emits condensed light, and a light incident surface is disposed near a converging position of the condensed light, the illuminance distribution of light emitted from the light source device is made uniform, and the light is emitted from a light exit surface. A rod-type integrator, and a reflection-type light modulation device that receives light emitted from the rod integrator, reflects the light according to a given image signal, and emits the light as image light representing an image. A relay optical system for guiding light emitted from the rod integrator to the reflection type light modulation device. The rod integrator sets a maximum inclination angle of light emitted from the light exit surface of the rod integrator with respect to a central axis perpendicular to the light exit surface, perpendicularly to the light incident surface of the condensed light emitted from the light source device. And a tilt angle changing unit for making the tilt angle smaller than the maximum tilt angle with respect to the central axis.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projector (projection display device) for projecting and displaying an image, and more particularly, to a projector including a rod integrator that can make the illuminance distribution of light uniform.
[0002]
[Prior art]
Generally, in a projector, light (illumination light) emitted from a light source device (illumination optical system) illuminates a light incident surface (also referred to as a light irradiation surface) of a light modulation device (also referred to as an electro-optical device). . Light incident from the light incident surface of the light modulation device is modulated according to an image signal (image information), and is emitted from the light modulation device as image light representing an image. Then, an image is displayed by projecting the image light emitted from the light modulation device onto a screen via a projection optical system.
[0003]
As the light modulation device, a reflection type light modulation device of a type in which modulated image light is emitted as reflected light from a light incident surface, and a modulated image light is emitted as transmitted light from a light emission surface opposite to the light incident surface. There is a type of transmission type light modulator. Examples of the reflection type light modulator include a micromirror type light modulator (reflection direction control type light modulator) such as a digital micromirror device (DMD, a trademark of TI), a reflection type liquid crystal panel, and the like. can give. An example of the transmission type light modulation device is a transmission type liquid crystal panel. Note that the DMD has a higher use efficiency of light applied to a light irradiation surface than a liquid crystal panel.
[0004]
In a projector using one light modulation device (also referred to as a “single-panel projector”), for example, color display can be realized as follows. That is, the illumination light is made incident on a color wheel having three color filters corresponding to the three primary colors of red (R), green (G), and blue (B), and the light of the three primary colors RGB included in the illumination light is sequentially circulated. And let it pass through. The light of the three primary colors emitted from the color wheel is sequentially applied to the light incident surface of the light modulator. The light modulation device modulates light sequentially incident from a light incident surface based on a color signal corresponding to the color of the light, thereby generating image light of a color component corresponding to each color signal. An image represented by the generated image light of each color (hereinafter, also referred to as a “color component image”) is sequentially projected. The three color component images projected in order are combined by the afterimage effect of the human eye, and appear as one color image.
[0005]
The display of the color image by sequentially displaying the color component images corresponding to the light of the three primary colors RGB is also referred to as “time-division display” or “field sequential display”.
[0006]
Here, in the case of the field sequential display, light of a color that cannot be transmitted through the color wheel is wasted. For example, G light and B light are wasted when R light is transmitted, B light and R light are transmitted when G light is transmitted, and R light and G light are wasted when B light is transmitted. For this reason, light emitted from the light source device is not sufficiently used as illumination light, and there is a problem in utilization efficiency.
[0007]
A method of solving such a problem and improving the light use efficiency is described in SOCITY FOR INFORMATION DISPLAY 2001 INTERNATIONAL SYMPOSIUM DIGEST OF TECHNICAL PAPERS / Volume / Reagent / Replacement / Reagent / Replacement / Release. Color (D. Scott Dewald, Steven M. Penn, and Michael Davis).
[0008]
FIG. 6 is a schematic plan view showing a main part of a projector using the SCR (Sequential Color Recovery) technology described in the above-mentioned document. The projector 1000 (hereinafter, referred to as “SCR projector”) includes a light source device 100, a rod integrator 200 for SCR (hereinafter, referred to as “SCR integrator”), and a color wheel 300 for SCR (hereinafter, “SCR integrator”). An SCR wheel is called.), A relay optical system 400, a reflection mirror 500, a field lens 600, a DMD 700, and a projection lens (projection optical system) 800 are sequentially arranged along the system optical axis 1000ax. It is configured.
[0009]
The light source device 100 includes an elliptical reflector 110 having a spheroidal reflective surface, and a light source lamp 120 using a high-pressure discharge lamp such as a metal halide lamp or a high-pressure mercury lamp. The central axis 100ax of the light source device 100 and the central axis 200ax of the SCR integrator 200 are arranged so as to coincide with the system optical axis 1000ax. The light source lamp 120 is disposed at the first focal point F1 of the elliptical reflector 110, and the light emitted from the light source device 100 becomes condensed light that is focused at the second focal point F2 of the elliptical reflector 110. The SCR integrator 200 is arranged such that the center of the light incident surface 202 (point on the central axis 200ax) is the second focal point F2 of the elliptical reflector 110. With such a configuration, the condensed light emitted from the light source device 100 can efficiently enter the inside from the light incident surface 202 of the SCR integrator 200. As the light source device, a light source device having a reflector having a paraboloidal reflecting surface may be used. However, in this case, since the emitted light is substantially parallel light, it is necessary to use a lens to collect the light.
[0010]
Light that has entered the inside from the light incident surface 202 of the SCR integrator 200 is emitted from the light exit surface 204 while being internally reflected. The SCR integrator 200 has a function of converting the light incident on the light incident surface 202 into uniform light and emitting the light from the light exit surface even when the illuminance distribution of the light incident on the light incident surface 202 is not uniform by repeating reflection inside. have.
[0011]
FIG. 7 is an explanatory diagram showing the SCR integrator 200. 7B shows a plan view of the SCR integrator 200, FIG. 7A shows a side view on the light incident surface 202 side, and FIG. 7C shows a side view on the light exit surface 204 side. . The SCR integrator 200 is a square rod-shaped translucent rod having a light incident surface 202 and a light exit surface 204 having a substantially rectangular outline.
[0012]
The SCR integrator 200 is entirely formed of a translucent member, and transmits the light incident from the light incident surface 202 to the light exit surface 204 by total internal reflection due to the difference in the refractive index of the medium at the boundary between the rod side surfaces. It has a function of guiding and substantially uniforming the illuminance distribution of light emitted from the light exit surface 204.
[0013]
The contour shape of the light exit surface 204 is usually similar to the light entrance surface in consideration of the illumination efficiency of light for illuminating the light entrance surface of the DMD 700. For example, since the aspect ratio (aspect ratio) of the light incident surface of the DMD 700 is about 4: 3 or about 16: 9, the contour shape of the light exit surface 204 is also about 4: 3 or about 16: 9. It is configured as follows.
[0014]
In addition, as the SCR integrator, a hollow rod integrator, which is also called a light tunnel and whose inner surface is covered with a reflection surface, can be used. In other words, even when the illuminance distribution of the light incident from the light incident surface is not uniform, the SCR integrator guides the light to the light exit surface while reflecting the light, so that the light has a uniform illuminance distribution. Any rod integrator having a function of converting the light and emitting the light from the light emission surface may be used.
[0015]
Outside the light incidence surface 202 of the SCR integrator 200, a reflection mirror 206 having a side in contact with the light incidence surface 202 as a reflection surface is formed. The reflective mirror 206 has a circular opening 206 a centered on a central axis 200 ax perpendicular to the light incident surface 202. Only light passing through the opening 206a can enter the inside of the SCR integrator 200 from the light incident surface 202.
[0016]
The size of the opening 206a is appropriately set in consideration of the efficiency of light incident from the light source device 100 into the SCR integrator 200 and the efficiency of light reflection by the reflecting mirror 206 described later. Normally, the opening diameter of the opening 206a is set to about １ ／ of the size of the reflection mirror 206 in the longitudinal direction.
[0017]
The reflection mirror 206 is formed by forming an aluminum film, a silver film, and the like on the light incident surface 202 except for a portion corresponding to the opening 206a. It can also be formed by depositing a dielectric multilayer film (such as a cold mirror). Also, it can be formed by attaching an ESR film (manufactured by 3M). It is to be noted that a material obtained by selectively forming an aluminum film, a silver film, a dielectric multilayer film, an ESR film, or the like on a flat transparent body (eg, a glass plate) is disposed close to the light incident surface 202 or bonded. It is also possible.
[0018]
Light emitted from the light exit surface 204 of the SCR integrator 200 shown in FIG. 6 enters the SCR wheel 300.
[0019]
FIG. 8 is an explanatory diagram showing the SCR wheel 300. The SCR wheel 300 has a disk-shaped filter surface 310 that is configured to be rotatable around a rotation shaft 320 by a motor (not shown). On the filter surface 310, the boundary lines (curves shown by solid lines in the figure) of the respective color filters of R (red), G (green), and B (blue) are positioned at the center point on the rotation axis 320 on the filter surface 310. They are arranged so as to form an Archimedes spiral at the center. Each of the R, G, and B color filters is a filter that transmits the corresponding color light and reflects the other color light. These color filters are formed by coating the corresponding dichroic films on the filter surface 310, respectively.
[0020]
The SCR wheel 300 has a filter surface 310 disposed close to and parallel to the light exit surface 204 of the SCR integrator 200.
[0021]
The light emitted from the light emission surface 204 of the SCR integrator 200 enters a plurality of color filters at a certain timing as shown by a broken line in FIG. 8, transmits only the corresponding color light, and transmits the other color light. reflect.
[0022]
FIG. 9 is an explanatory diagram showing light reflected by the SCR wheel 300. For example, among the light emitted from the light emission surface 204 of the SCR integrator 200 and incident on the R light transmission filter 310R formed on the filter surface 310 of the SCR wheel 300, R light is transmitted, and G light and B light are transmitted. The light is reflected and reenters the inside of the SCR integrator 200 from the light exit surface 204.
[0023]
The reflected G light and B light (hereinafter referred to as “GB light”) return to the light incident surface 202 while repeating reflection inside the SCR integrator 200. Since the reflection mirror 206 is formed on the light incident surface 202, the GB light that has reached the light incident surface 202 excludes a part of the GB light that passes through the opening 206a of the reflection mirror 206. Is reflected by
[0024]
The GB light reflected by the reflection mirror 206 travels toward the light exit surface 204 while reflecting inside the SCR integrator 200, exits from the light exit surface 204, and enters the SCR wheel 300 again. When the GB light that has entered the SCR wheel 300 again enters a transmissible color filter, for example, the G light transmission filter 310G for G light and the B light transmission filter 310B for B light, it passes through the SCR wheel 300. On the other hand, the GB light that has re-entered the SCR wheel 300 can be used as illumination light. When the GB light has entered the non-transmittable filter, that is, the R light transmission filter 310R, it is reflected again and can be transmitted. The light reciprocates in the SCR integrator 200 until it enters the filter and is used as effective light.
[0025]
Although the above description has been made by taking as an example the case of light that first enters the R light filter 310R, the same applies to light that first enters the other G light transmission filter 310G or B light transmission filter 310B. is there.
[0026]
As described above, in the SCR projector 1000, it is possible to reuse the light reflected by the SCR wheel 300 and not effectively used. Therefore, it is possible to efficiently use the light emitted from the light source device 100 while suppressing the waste of light due to the color wheel, which is generated in the field sequential display. The technique of reusing light in this way is called "SCR technique".
[0027]
6 forms an image of light on the light exit surface 204 of the SCR integrator 200 that has passed through the SCR wheel 300 at a predetermined imaging magnification on a region including at least the light incident surface 702 of the DMD 700. It has a function and can be constituted by at least one or more lenses.
[0028]
Here, since the filter surface 310 of the SCR wheel 300 is disposed close to the light exit surface 204 of the SCR integrator 200, the relay optical system 400 forms an image of the light passing through the SCR wheel 300 at a predetermined imaging magnification. You can think of it as an image. The size (horizontal or vertical size) DA of an image formed as an illumination area (hereinafter, also referred to as an “image of an illumination area”) is equal to the size of the light exit surface of the SCR integrator 200 ( Assuming that DI is the size in the horizontal or vertical direction and ks is the imaging magnification, it is expressed by the following equation.
[0029]
DA = DI · ks (1)
[0030]
The predetermined imaging magnification ks is set such that the size (horizontal or vertical size) of the image of the illumination area DA is equal to the size of the light incident surface 702 so that the light irradiation surface of the DMD 700 is efficiently illuminated. They are set to be approximately equal. Usually, the imaging magnification ks is set in a range of about 1.5 to about 2.5 times.
[0031]
The reflection mirror 500 reflects the light emitted from the relay optical system 400 so as to enter the DMD 700 via the field lens 600.
[0032]
The DMD 700 reflects image light representing an image in the direction of the projection lens 800 by reflecting light incident from the light incident surface 702 on a micromirror corresponding to each pixel according to a given image signal (image information). This is a reflection direction control type optical modulator (micromirror type optical modulator) having a function of emitting light. Image light emitted from the light incident surface 702 of the DMD 700 is projected via the field lens 600 and the projection lens 800. Thus, the image represented by the image light is projected and displayed.
[0033]
Note that the system optical axis 1000ax from the reflection mirror 500 to the DMD 700 has a predetermined inclination with respect to the system optical axis 1000ax from the DMD 700 to the projection lens 800 due to the restriction on the function of controlling the above-described reflection direction of the DMD 700. It is required to have. Therefore, the reflection mirror 500 is arranged so as to reflect the central axis of the light emitted from the relay optical system 400 and have a predetermined inclination with respect to the system optical axis 1000ax from the DMD 700 to the projection lens 800. . However, the reflection mirror 500 can be omitted depending on the arrangement of the optical system from the light source device 100 to the relay optical system 400. Further, the number of the reflecting mirrors 500 is not necessarily one, and a plurality of reflecting mirrors can be combined.
[0034]
Here, the “light incident surface 702 of the DMD 700” indicates a region where the irradiated light can be used as image light, that is, a region where the micro mirror corresponding to each pixel described above is formed.
[0035]
In addition, the “predetermined inclination” is appropriately determined according to a device to be used, and is not a problem in the following description, and thus the description is omitted.
[0036]
FIG. 10 is an explanatory diagram schematically showing an image of light formed on a region including at least the light incident surface 702 of the DMD 700. The light emitted from the light exit surface 204 of the SCR integrator 200 enters a plurality of color filters at a certain timing as shown by a broken line in FIG. Therefore, an image of light formed by passing through the SCR wheel 300 is divided into a plurality of R, G, and B color light regions as shown in FIG. In addition, since the boundaries of the color filters move in the radial direction in accordance with the rotation of the SCR wheel 300, a plurality of R, G, and B light beams are formed in the image of the light that has passed through the SCR wheel 300. For example, as shown in FIGS. 10A and 10B, the pattern of the area divided into the color light changes from the state at the display timing T = 0 to the state at the display timing T = 1, for example. . The display timing indicates a unit time for updating data of a display image.
[0037]
Therefore, at a certain display timing, it is necessary to supply each pixel of the DMD 700 with an image signal corresponding to a color component image corresponding to the color of light applied to the pixel. For example, the color pattern of the light to be illuminated can be uniquely determined according to the position of a reference point (not shown) provided on the SCR wheel 300 so as to change in accordance with the rotation of the SCR wheel. . An image processing circuit (not shown) obtains pattern information of a corresponding light color by observing the position of the reference point, generates an image signal of each pixel according to the pattern information, and supplies the image signal to the DMD 700.
[0038]
As described above, in the SCR projector 1000, a color component image corresponding to the color of the irradiated light is displayed on each pixel. Then, the displayed color component images of the respective pixels are combined by the afterimage effect of the human eye, and thus appear as one color image.
[0039]
[Problems to be solved by the invention]
By the way, the size of the arc image of the light source lamp 120 (hereinafter, referred to as “secondary light source image”) formed near the light incident surface 202 of the SCR integrator 200 is determined as follows. That is, the size of the arc image of the light source lamp 120 (the size in the horizontal or vertical direction) is Ds, the size of the secondary light source image (the size in the horizontal or vertical direction) is Di, and the size of the elliptical reflector 110 is Assuming that the first and second focal lengths are f1 and f2, the size Di of the secondary light source image is represented by the following equation.
[0040]
Di = Ds · f2 / f1 (2)
[0041]
Since the size Ds of the arc image has a finite size, the size of the secondary light source image also has a finite size as can be seen from the above equation (2). Therefore, the size Di of the secondary light source image may be larger than the size of the opening 206a of the reflection mirror 206.
[0042]
In order to efficiently use the condensed light emitted from the light source device 100, it is preferable that the size Di of the secondary light source image be smaller than the size of the opening 206a of the reflection mirror 206. As can be seen from the above equation (2), the size of the secondary light source image can be reduced by increasing the first focal length f1 or decreasing the second focal length f2. However, simply reducing the size of the secondary light source image has the following problems.
[0043]
FIG. 11 is an explanatory diagram illustrating a problem when the secondary light source image is reduced. FIG. 11A shows the illumination optical system portion of the SCR projector 1000 in an enlarged manner. As shown in FIG. 11A, the first focal length of the elliptical reflector 110 of the light source device 100 is f1, and the second focal length is f2. The size Di of the secondary light source image is represented by the above equation (2). The maximum inclination angle (hereinafter, simply referred to as “incident angle”) of the condensed light emitted from the light source device 100 with respect to the central axis 100ax (the central axis of the light source device 100) is θi, and the light emission of the SCR integrator 200 is performed. The maximum inclination angle of the light emitted from the surface 204 with respect to the central axis 100ax (hereinafter, simply referred to as “emission angle”) is θo. The exit angle θo is substantially equal to the incident angle θi. The central axis 200ax of the SCR integrator 200 (the central axis perpendicular to the light incident surface 202 and the light exit surface 204) coincides with the central axis 100ax of the light source device 100.
[0044]
FIG. 11B illustrates a light source device 100 ′ having an elliptical reflector 110 ′ having a second focal length f2 ′ (<f2) shorter than the elliptical reflector 110 of the light source device 100 in FIG. 11A. Is shown.
[0045]
The size Di ′ of the secondary light source image in the case of FIG. 11B is represented by the following equation.
[0046]
Di ′ = Ds · f2 ′ / f1 (3)
[0047]
Further, the incident angle of the condensed light emitted from the light source device 100 ′ is θi ′, and the emission angle of the light emitted from the light emission surface 204 of the SCR integrator 200 is θo ′. The exit angle θo ′ is substantially equal to the incident angle θi ′.
[0048]
In the case of FIG. 11B, as can be seen by comparing the above equations (2) and (3), the size of the secondary light source image is reduced by satisfying Di ′ <Di by f2 ′ <f2. Is possible.
[0049]
However, assuming that the size of the opening surface of the elliptical reflector 110 ′ in FIG. 11B is equal to the size of the opening surface of the elliptical reflector 110 in FIG. 11A, θi ′> θi, and accordingly θo. '> Θo. For this reason, in order to efficiently use the light emitted from the SCR integrator 200, the size Ld '(lens diameter) of the relay optical system 400' in FIG. It needs to be larger than the lens diameter Ld of the system 400. That is, if the size of the secondary light source image is simply reduced, a relay optical system having a large lens aperture is required. However, a relay optical system having a large lens aperture may have problems such as aberrations and manufacturing costs.
[0050]
The present invention has been made to solve the above-described problem in the related art, and easily improves the light use efficiency in a projector including a rod integrator that can make the illuminance distribution of light uniform. The aim is to provide a technology that can.
[0051]
[Means for Solving the Problems and Their Functions and Effects]
In order to solve at least a part of the problems described above, the present invention is a projector that projects an image,
A light source device for emitting condensed light,
A rod integrator is provided in which a light incident surface is disposed near a converging position of the condensed light, and a rod integrator for uniformizing the illuminance distribution of light emitted from the light source device and emitting the light from the light emitting surface.
Light emitted from the rod integrator is incident, and the light is emitted from the rod integrator, reflecting the light according to a given image signal and emitting the reflected light as image light representing an image; A relay optical system for guiding to the reflection type light modulation device,
The rod integrator sets a maximum inclination angle of light emitted from the light exit surface of the rod integrator with respect to a central axis perpendicular to the light exit surface, perpendicularly to the light incident surface of the condensed light emitted from the light source device. And a tilt angle changing unit for making the tilt angle smaller than the maximum tilt angle with respect to the central axis.
[0052]
In the projector according to the aspect of the invention, the maximum inclination angle of the light emitted from the light exit surface of the rod integrator with respect to the central axis perpendicular to the light exit surface is set to the central axis perpendicular to the light entrance surface of the condensed light emitted from the light source device. Can be made smaller than the maximum inclination angle with respect to, and as described in the conventional example, the arc image of the light source lamp can be reduced without increasing the lens aperture of the relay optical system. This makes it possible to easily improve the utilization efficiency of light emitted from the light source device.
[0053]
Here, the inclination angle changing unit can be easily formed by a concave lens.
[0054]
Note that the rod integrator has a hollow interior, and has, at both ends, an entrance opening surface corresponding to the light entrance surface and an exit opening surface corresponding to the light exit surface, and a reflection surface on the inner side surface of the interior. A hollow rod having a shape, and guiding the light incident from the entrance opening surface to the exit opening surface while reflecting the light on the inner side surface, so that the illuminance distribution of the light exiting from the exit opening surface is substantially uniform. It is preferable that the concave lens is provided at an end having the entrance opening surface, the hollow lens including a hollow rod to be formed.
[0055]
Alternatively, the rod integrator is a columnar rod formed entirely of a translucent member, and converts the light incident from the light incident surface of the rod into a refractive index difference between the internal medium and the external medium. It is also preferable that the rod includes a rod for guiding the light emitted from the light exit surface to the light exit surface by total internal reflection of the rod to substantially uniform the illuminance distribution of light emitted from the light exit surface, and the concave lens is provided near the light incident surface of the rod. .
[0056]
In any of the rod integrators described above, it is easy to make the maximum inclination angle of the light emitted from the light exit surface of the rod integrator smaller than the maximum inclination angle of the condensed light emitted from the light source device. .
[0057]
In the above projector,
Further, a reflection type color filter which is disposed close to the light exit surface of the rod integrator and transmits desired color light and reflects other color light, divides the light emitted from the rod integrator into a plurality of color lights. A plurality of color lights included in the transmitted light are formed in a spiral shape so as to be transmitted, and are rotated around a rotation axis substantially parallel to a central axis of the light emitted from the light exit surface of the rod integrator. The segmented area includes a color wheel configured to change cyclically, and the concave surface of the concave lens is provided at a portion substantially centered on the central axis of the condensed light emitted from the light source device. Yes,
The rod integrator is a reflection mirror further provided in the vicinity of the concave lens, has an opening in a portion corresponding to the concave surface of the concave lens, is reflected by the color wheel on the outer peripheral side of the opening, It is also possible to provide a reflection mirror having a reflection surface for reflecting light returning from the light exit surface side to the light incident surface side in the rod integrator.
[0058]
According to the above configuration, the present invention can be applied to a projector using the SCR technology.
[0059]
In addition, it is preferable that the reflection mirror is formed on a surface of the concave lens facing the exit opening surface.
[0060]
In this case, it is possible to suppress the loss of light in the rod integrator as compared with the case where the reflection mirror is not formed on the surface of the concave lens facing the exit opening side.
[0061]
Further, the present invention is an illumination optical system for illuminating a predetermined area,
A light source device for emitting condensed light,
A rod integrator is provided in which a light incident surface is disposed near a converging position of the condensed light, and a rod integrator for uniformizing the illuminance distribution of light emitted from the light source device and emitting the light from the light emitting surface.
A relay optical system for guiding light emitted from the light exit surface of the rod integrator to the predetermined region,
The rod integrator sets a maximum inclination angle of light emitted from the light exit surface of the rod integrator with respect to a central axis perpendicular to the light exit surface, perpendicularly to the light incident surface of the condensed light emitted from the light source device. And a tilt angle changing unit for making the tilt angle smaller than the maximum tilt angle with respect to the central axis.
[0062]
If the illumination optical system of the invention is applied to a projector, the projector of the invention can be configured.
[0063]
BEST MODE FOR CARRYING OUT THE INVENTION
A. Example:
FIG. 1 is a schematic plan view showing an SCR projector according to an embodiment of the present invention. This SCR projector 1000A is different from the conventional example in that the SCR integrator 200 of the SCR projector 1000 (FIG. 6) is replaced with an SCR integrator 200A, and the light source device 100 is equivalent to the light source device 100 ′ (FIG. 11). It has the same configuration except that it has been replaced with 100A. The components 100A, 200A, 300, 400, 600, 700, and 800 except for the reflection mirror 500 indicate the minimum components required for the SCR projector, and include a reflection mirror and a lens between the components. Various optical elements can be appropriately arranged. Since the function of each component is exactly the same as that of the conventional example, the SCR integrator 200A will be particularly described below.
[0064]
FIG. 2 is an explanatory diagram showing the SCR integrator 200A. As shown in the perspective view of FIG. 2A, the SCR integrator 200A has a hollow hollow rod 210 having a hollow interior, open ends at both ends, and a substantially rectangular outline at both ends. I have.
[0065]
A reflection mirror is formed on the entire hollow inner surface. This reflection mesh is formed by an aluminum film, a silver film, or the like. It can also be formed by depositing a dielectric multilayer film (such as a cold mirror). Also, it can be formed by attaching an ESR film (manufactured by 3M).
[0066]
The hollow rod 210 guides the light incident from the opening surface at one end to the opening surface at the other end while reflecting the light on the inner surface, and the illuminance distribution of the light emitted from the opening surface at the other end. Has a function of substantially uniformity. This hollow rod 210 has the same function as the translucent rod included in the conventional SCR integrator 200 (FIG. 6).
[0067]
One open end of the hollow rod 210 corresponds to the light incident surface 212, and the other end corresponds to the light exit surface 214. As shown in FIG. 2B, a concave lens 220 is fitted in one end corresponding to the light incident surface 212.
[0068]
In the concave lens 220, a concave surface 222a is formed on one surface 222 facing outward from the hollow rod 210, and a reflection mirror 230 is formed on the other surface 224 facing inward. The reflection mirror 230 corresponds to the reflection mirror 206 in the conventional SCR integrator 200 (FIG. 7). The concave surface 222a is formed on one surface 222 of the concave lens 220 at a part centered on the central axis 200Aax of the SCR integrator 200A perpendicular to the light incident surface 212 and the light exit surface 214. In the reflection mirror 230, an opening (not shown) is formed in a portion corresponding to the concave surface 222 a of the concave lens 220, similarly to the opening 206 a of the reflection mirror 206. In addition, on the surface on which the reflection mirror 230 is formed, a concave surface may be formed at a portion corresponding to the opening of the reflection mirror 230. Further, the reflection mirror 230 may be formed on the surface 222 on which the concave surface 222a is formed.
[0069]
FIG. 3 is an explanatory diagram showing functions of the SCR integrator 200A. The condensed light emitted from the light source device 100A has an incident angle θi that is larger than the incident angle θi when the light source device 100 is used, as in the case of using the light source device 100 ′ described in the above-described problem (FIG. 11). ', The light enters the inside of the SCR integrator 200A via the concave surface 222a of the concave lens 220.
[0070]
Since the concave lens 220 has a function of diverging light, that is, has a so-called negative lens power, the maximum inclination angle θp of the light incident inside via the concave lens 220 (hereinafter, referred to as “internal incident angle”) .) Can be made smaller than the incident angle θi ′. Accordingly, by appropriately selecting the characteristics of the concave lens, the internal incident angle θp can be made substantially equal to the incident angle θi (FIG. 11) when the light source device 100 is used as in the conventional SCR projector 1000. It is. In general, the incident angle to the hollow rod 210 and the exit angle are equal, so that the exit angle θo ′ in this example can be made substantially equal to the incident angle θi in the conventional SCR projector 1000, and the exit angle θo (FIG. It can be almost equal to 11). Therefore, as described in the problem, there is no need to use a relay optical system having a large lens diameter in order to reduce the size of the secondary light source image. Further, if the internal incident angle θp is made smaller than the incident angle θi, a relay optical system having a smaller lens diameter can be used, and the size of the apparatus can be reduced. Note that the concave lens 220 corresponds to the tilt angle changing unit of the present invention.
[0071]
Further, since the light source device 100A is configured using the elliptical reflector 110 ′ having the second focal length f2 ′ shorter than the second focal length f2 of the elliptical reflector 110 of the light source device 100 of the conventional example, the SCR integrator 200A Can be made smaller than the size Di of the secondary light source image in the light source device 100 of the conventional example. As a result, it is possible to improve the efficiency of light incident on the SCR integrator 200A.
[0072]
As described above, in the projector 1000A of this embodiment, the relay optical system 400 of the projector 1000 of the conventional example can be used as it is by using the SCR integrator 200A. The problem that an optical system needs to be used can be solved, and the light use efficiency can be easily improved. In addition, a uniform and brighter image can be easily projected and displayed.
[0073]
B. Modification:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist of the present invention, and for example, the following modifications are possible.
[0074]
B1. Modification 1
FIG. 4 is a schematic perspective view showing an SCR integrator 200B as a modification.
[0075]
This SCR integrator 200B is not a hollow rod 210 as in the SCR integrator 200A (FIG. 2) in the embodiment, but a rod 210B (light transmitting) in which the whole inside is formed of a translucent member like the SCR integrator 200 in the conventional example. A concave lens 220 (FIG. 2) as a tilt angle changing portion is bonded on a light incident surface 212B of the sex rod (a flexible rod) on the surface on which the reflection mirror 230 is formed.
[0076]
Even when the SCR integrator 200B of the present modification is replaced with the SCR integrator 200A of the embodiment, the same operation and effect as those of the embodiment can be obtained.
[0077]
B2. Modified example 2:
FIG. 5 is an explanatory diagram showing an SCR integrator 200C as another modification.
[0078]
The SCR integrator 200C has a configuration in which a reflection mirror 230C corresponding to the reflection mirror 206 is formed on a light incident surface 212C of a light transmitting rod 210C as shown in a schematic perspective view of FIG. ing. The configuration of the SCR integrator 200C is basically similar to that of the conventional SCR integrator 200 (FIG. 2), but differs from the SCR integrator 200 except for the following points.
[0079]
FIG. 5 (B) shows a schematic cross section of the SCR integrator 200C cut in a direction indicated by an arrow A as shown by a dashed line in FIG. 5 (A). As shown in the schematic section, the light-transmitting rod 210C is formed of a light-transmitting member having a refractive index of n2, and has a concave portion 210Ca on both surfaces (hereinafter, referred to as a “concave portion”). Two portions 210Cb and 210Cc formed of a light-transmitting member having a refractive index n1 sandwiching the concave portion 210Ca and having a convex surface whose surface corresponding to the concave surface is substantially equal to the curvature of the concave surface (hereinafter, referred to as “ (Referred to as a “convex-shaped portion”).
[0080]
The refractive index n2 of the concave portion 210Ca is larger than the refractive index n1 of the two convex portions 210Cb and 210Cc. As a result, the concave portion 210Ca functions as a concave lens, and the maximum inclination angle θ2 of the light incident on and emitted from the concave portion 210Ca can be made smaller than the maximum inclination angle θ1 of the incident light. This concave portion 210Ca corresponds to the tilt angle changing portion of the present invention.
[0081]
Therefore, the SCR integrator 200C of the present modification is the same as the SCR integrator 200A of the embodiment and the SCR integrator 200B of the modification, and the same operation and effect can be obtained by replacing the SCR integrator 200A of the embodiment. .
[0082]
B3. Modification 3:
In the above-described embodiment and the first modification, the configuration in which the concave lens is formed on the light incident surface side is shown. However, the configuration in which the concave lens is formed on the light exit surface side is also possible. In this case, it is necessary to form a reflection mirror formed on the surface of the concave lens on the light incident surface.
[0083]
B4. Modification 4:
In the above embodiment, the projector including the DMD is described as an example of the reflection type light modulation device. However, for example, the invention can be applied to a projector including one reflection type liquid crystal panel. The present invention can be applied to a projector using various reflection type modulation devices.
[0084]
B5. Modification 5:
In the above embodiment, the projector using the SCR technology has been described as an example, but the present invention can be applied to a projector that does not use the SCR technology. In the case of a projector that does not use the SCR technology, the reflection mirror formed on the light incident surface side of the SCR integrator in the embodiment and the modification can be omitted. Further, as the concave lens, a lens having a concave surface formed on the front surface instead of a part of the surface having the concave surface may be used.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an SCR projector according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing an SCR integrator 200A.
FIG. 3 is an explanatory diagram showing functions of an SCR integrator 200A.
FIG. 4 is a schematic perspective view showing an SCR integrator 200B as a modification.
FIG. 5 is an explanatory diagram showing an SCR integrator 200C as another modified example.
FIG. 6 is a schematic plan view showing a main part of a projector using the SCR technology.
FIG. 7 is an explanatory diagram showing an SCR integrator 200.
FIG. 8 is an explanatory view showing an SCR wheel 300.
FIG. 9 is an explanatory diagram showing light reflected by the SCR wheel 300.
FIG. 10 is an explanatory diagram schematically showing an image of light formed on a region including at least a light incident surface 702 of a DMD 700.
FIG. 11 is an explanatory diagram showing a problem when a secondary light source image is reduced.
[Explanation of symbols]
1000 ... Projector (SCR projector)
1000A ... Projector (SCR projector)
1000ax ... System optical axis 100 ... Light source device 100 '... Light source device 100A ... Light source device 100ax ... Central axis 110 ... Elliptical reflector 120 ... Light source lamp 110' ... Elliptical reflector 200 ... Rod integrator (SCR integrator)
200ax central axis 202 light incident surface 204 light exit surface 206 reflecting mirror 200A rod integrator (SCR integrator)
200Aax central axis 210 hollow rod 212 light incident surface 214 light exit surface 220 concave lenses 222 and 224 surface 222a concave surface 230 reflecting mirror 200B rod integrator (SCR integrator)
210B: translucent rod 212B: light incident surface 214B: light exit surface 200C: rod integrator (SCR integrator)
200Cax central axis 210C translucent rod 212C light incident surface 214C light emitting surface 210Ca concave shape portion 210Cb, 210Cc convex shape portion 230C reflection mirror 300 SCR wheel (color wheel for SCR)
310 filter surface 310R R light transmission filter 310G G light transmission filter 310B B light transmission filter 320 rotating shaft 400 relay optical system 400ax central axis 500 reflecting mirror 600 field lens 600ax central axis 700 DMD
700ax central axis 702 light incident surface 800 projection lens (projection optical system)

Claims (7)

A projector for projecting an image,
A light source device for emitting condensed light,
A rod integrator is provided in which a light incident surface is disposed near a converging position of the condensed light, and a rod integrator for uniformizing the illuminance distribution of light emitted from the light source device and emitting the light from the light emitting surface.
Light emitted from the rod integrator is incident, and the light is emitted from the rod integrator, reflecting the light according to a given image signal and emitting the reflected light as image light representing an image; A relay optical system for guiding to the reflection type light modulation device,
The rod integrator sets a maximum inclination angle of light emitted from the light exit surface of the rod integrator with respect to a central axis perpendicular to the light exit surface, perpendicularly to the light incident surface of the condensed light emitted from the light source device. Characterized in that it comprises a tilt angle changing unit for making it smaller than the maximum tilt angle with respect to the central axis,
projector. The projector according to claim 1, wherein the inclination angle changing unit includes a concave lens. The projector according to claim 2, wherein
The rod integrator has a hollow interior, and has, at both ends, an entrance opening surface corresponding to the light entrance surface and an exit opening surface corresponding to the light exit surface, and a reflection surface on the inner side surface of the interior. A column-shaped hollow rod, which guides the light incident from the entrance opening surface to the exit opening surface while reflecting the light on the inner surface, and makes the illuminance distribution of the light exiting from the exit opening surface substantially uniform. A projector comprising a hollow rod, wherein the concave lens is provided at an end having the entrance aperture surface. The projector according to claim 2, wherein
The rod integrator is a columnar rod formed entirely of a translucent member. The rod integrator converts the light incident from the light incident surface of the rod into an inner part due to a difference in refractive index between an internal medium and an external medium. A projector, comprising: a rod that guides light to a light exit surface by total reflection and makes the illuminance distribution of light emitted from the light exit surface substantially uniform, and the concave lens is provided near a light incident surface of the rod. The projector according to claim 3 or 4, wherein:
Further, a reflection type color filter which is disposed close to the light exit surface of the rod integrator and transmits desired color light and reflects other color light, divides the light emitted from the rod integrator into a plurality of color lights. A plurality of color lights included in the transmitted light are formed in a spiral shape so as to be transmitted, and are rotated around a rotation axis substantially parallel to a central axis of the light emitted from the light exit surface of the rod integrator. The segmented area includes a color wheel configured to change cyclically, and the concave surface of the concave lens is provided at a portion substantially centered on the central axis of the condensed light emitted from the light source device. Yes,
The rod integrator is a reflection mirror further provided in the vicinity of the concave lens, has an opening in a portion corresponding to the concave surface of the concave lens, is reflected by the color wheel on the outer peripheral side of the opening, A projector, comprising: a reflection mirror having a reflection surface that reflects light returning from the light exit surface side to the light incident surface side in the rod integrator. The projector according to claim 5, wherein the reflection mirror is formed on a surface of the concave lens facing the exit opening surface. An illumination optical system that illuminates a predetermined area,
A light source device for emitting condensed light,
A rod integrator is provided in which a light incident surface is disposed near a converging position of the condensed light, and a rod integrator for uniformizing the illuminance distribution of light emitted from the light source device and emitting the light from the light emitting surface.
A relay optical system for guiding light emitted from the light exit surface of the rod integrator to the predetermined region,
The rod integrator sets a maximum inclination angle of light emitted from the light exit surface of the rod integrator with respect to a central axis perpendicular to the light exit surface, perpendicularly to the light incident surface of the condensed light emitted from the light source device. Characterized in that it comprises a tilt angle changing unit for making it smaller than the maximum tilt angle with respect to the central axis,
Illumination optics.

Images