JP2006163018A - Light source apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source apparatus efficiently supplying respective color beams by reducing chromatic aberrations and having compact constitution and a projector using the light source apparatus. <P>SOLUTION: The light source apparatus is provided with: light source parts 101, 102 for supplying light; a first mirror 103 of which the concave surface is turned to the light source parts 101, 102; and a second mirror 107 arranged oppositely to the first mirror 103. The first mirror 103 reflects light from the light source parts 101, 102 to the direction of the second mirror 107, and the second mirror 107 reflects light from the first mirror 103 to emit the light to a prescribed direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light source device and a projector, and more particularly to a technology of a light source device including a plurality of solid state light emitting elements.

  In recent years, it has been proposed to use a solid state light emitting device as a light source of a projector. In particular, a light-emitting diode (hereinafter referred to as “LED”) that is a solid-state light-emitting element is characterized by being ultra-compact, ultra-light, and long-life. Further, LEDs have been improved in brightness and efficiency by development and improvement for use for illumination purposes. For this reason, in order to reduce the size and power consumption of the projector, it is expected to use an LED for the light source device of the projector.

  When the currently developed LED is used for a projector, it is necessary to use a plurality of LEDs in order to obtain a bright image. When a plurality of LEDs are used, it is desirable that light from each LED is efficiently incident on the spatial light modulator. For example, Patent Document 1 proposes a technique for efficiently causing light from a plurality of LEDs to enter a spatial light modulator.

JP 2001-343706 A

  In the configuration proposed in Patent Document 1, a lens for converging light from a plurality of LEDs is used. When an image is formed using a lens, so-called chromatic aberration in which the position and size of the image are shifted for each color may occur. When chromatic aberration occurs in the light source device, the use efficiency of light in a specific wavelength region is reduced, so that color reproducibility may be reduced. Further, the configuration proposed in Patent Document 1 is considered to increase the size in the optical axis direction in order to ensure a predetermined focal length. As described above, in the conventional technique, there is a problem that the color reproducibility may be lowered and it is difficult to obtain a compact configuration. The present invention has been made in view of the above-described problems, and provides a light source device having a compact configuration that can efficiently supply each color light by reducing chromatic aberration and a projector using the light source device. Objective.

  In order to solve the above-described problems and achieve the object, according to the present invention, a light source unit that supplies light, a first mirror provided with a concave surface facing the light source unit, and a first mirror A first mirror that reflects light from the light source unit in the direction of the second mirror, and the second mirror has a second mirror from the first mirror. It is possible to provide a light source device that reflects light and emits the light in a predetermined direction.

  Light from the light source unit is reflected by the first mirror and travels in the direction of the second mirror. Since the first mirror is provided with the concave surface facing the light source section, the light reflected by the first mirror converges until it enters the second mirror. The light incident on the second mirror is reflected by the second mirror and then emitted in a predetermined direction. The light source device can efficiently guide light from the light source unit in a predetermined direction by using the first mirror and the second mirror. The present invention includes a configuration in which light reflected by the second mirror travels directly in a predetermined direction, and a configuration in which the traveling direction is converted by another member, for example, the third mirror, and then travels in the predetermined direction. .

  In the first mirror and the second mirror, light in any wavelength region is similarly reflected. The light source device can reduce chromatic aberration if light of any wavelength can travel in the same manner. By reducing chromatic aberration, the light source device can efficiently supply light of any wavelength. In addition, the light source device can be made compact by bending the optical path with the first mirror and the second mirror. Also in the case of providing a plurality of light source units, the light source device can be reduced in size by arranging the light source units around the second mirror. Thereby, each color light can be efficiently supplied by reducing chromatic aberration, and a light source device having a compact configuration can be obtained.

  According to a preferred aspect of the present invention, it is desirable that the first mirror has an opening that allows the light reflected by the second mirror to pass through. The light reflected by the second mirror and traveling in the direction of the first mirror passes through the opening of the first mirror and is emitted in a predetermined direction. Thereby, the light reflected by the second mirror can be emitted in a predetermined direction.

  According to a preferred aspect of the present invention, it is desirable that the second mirror is a curved surface with a convex surface directed toward the first mirror. By using the second mirror with the convex surface facing the first mirror, the light reflected by the second mirror can be diverged. For example, light traveling in a predetermined direction can be collimated by diverging light converged by reflection on the first mirror by reflection on the second mirror.

  As a preferred aspect of the present invention, it is desirable that the second mirror is a curved surface with a concave surface facing the first mirror side. By using the second mirror with the concave surface facing the first mirror side, the light reflected by the second mirror can be converged. Thereby, the light traveling in the predetermined direction can be converged.

  As a preferred embodiment of the present invention, the second mirror is preferably a substantially flat plane. Thereby, the light incident on the second mirror from the first mirror can be bent and advanced as it is.

  As a preferred aspect of the present invention, it is desirable that at least one of the first mirror and the second mirror is an aspherical curved surface. Thereby, spherical aberration can be reduced.

  Moreover, as a preferable aspect of the present invention, it is desirable to have a third mirror that reflects light reflected by the second mirror in a predetermined direction. The light incident on the second mirror travels in the direction of the third mirror after being reflected by the second mirror. The light incident on the third mirror is reflected by the third mirror and then emitted in a predetermined direction. Thereby, light can be emitted in a predetermined direction.

  Furthermore, according to the present invention, the light source device described above, a spatial light modulation device that modulates light from the light source device in accordance with an image signal, and a projection optical system that projects light from the spatial light modulation device are provided. A projector can be provided. By using the light source device described above, each color light can be supplied efficiently and a compact configuration can be achieved. Thus, by efficiently supplying each color light, it is possible to obtain a small projector with good color reproducibility.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a projector 100 according to Embodiment 1 of the present invention. The projector 100 is a so-called single-plate projector that includes a single spatial light modulator 130. The projector 100 has a light source device 110. The light source device 110 includes LEDs 101 and 102 that are light source units. The LEDs 101 and 102 supply white light including red light (hereinafter referred to as “R light”), green light (hereinafter referred to as “G light”), and blue light (hereinafter referred to as “B light”). . Light from the light source device 110 enters the rod integrator 120.

  The rod integrator 120 makes the light intensity distribution from the light source device 110 substantially uniform. The rod integrator 120 is made of a transparent glass member having a quadrangular prism shape. The light incident on the rod integrator 120 travels inside the rod integrator 120 while repeating total reflection at the interface between the glass member and air. The rod integrator 120 is not limited to a solid structure using a glass member, and may have a hollow structure in which an inner surface is formed of a reflective surface. In the case of a rod integrator having an inner surface as a reflecting surface, light incident on the rod integrator travels inside the rod integrator while being repeatedly reflected on the reflecting surface. Further, the rod integrator may be configured to combine a glass member and a reflecting surface.

  The light from the rod integrator 120 enters the spatial light modulator 130. The spatial light modulator 130 is a transmissive liquid crystal display device that modulates light from the light source device 110 according to an image signal. Each pixel of the spatial light modulator 130 is provided with an R light transmission color filter, a G light transmission color filter, and a B light transmission color filter.

  The light from the light source device 110 is modulated by being separated into R light, G light, and B light by a color filter. In addition to the color filter, the spatial light modulator 130 may further include a transparent member that transmits a part of the light from the light source device 110 as it is. By transmitting part of the light from the light source device 110 as it is through the transparent member, the brightness of the projected image can be improved. Each color light modulated by the spatial light modulator 130 is projected onto the screen 150 by the projection optical system 140.

  The light source device 110 includes a first mirror 103 and a second mirror 107. The first mirror 103 is an aspherical curved surface, and is provided with a concave surface facing the LEDs 101 and 102. An opening 105 is provided substantially at the center of the first mirror 103. The second mirror 107 is provided in the vicinity of the LEDs 101 and 102 and at a position facing the first mirror 103. The second mirror 107 is an aspherical curved surface, and is provided with a convex surface facing the first mirror 103 side.

  The first mirror 103 and the second mirror 107 are both arranged so that their center positions substantially coincide with the optical axis AX. In the light source device 110, the first mirror 103 and the second mirror 107 are arranged so that the normal line of the second mirror 107 and the normal line of the first mirror 103 are substantially parallel. With this configuration, the light from the first mirror 103 is reflected by the second mirror 107 and then reflected in the direction of the opening 105. The opening 105 is provided with a size that allows the light reflected by the second mirror 107 to pass therethrough.

  A highly reflective member such as a metal film or a dielectric multilayer film is provided on the concave surface of the first mirror 103 and the convex surface of the second mirror 107. An aspherical surface indicates a curved surface other than a spherical surface, and includes a paraboloid, a hyperboloid, and other free-form surfaces. The positions, sizes, and shapes of the first mirror 103 and the second mirror 107 are not limited to those illustrated. The first mirror 103 and the second mirror 107 are configured such that the light reflected by the first mirror 103 enters the second mirror 107 and the light reflected by the second mirror 107 passes through the opening 105. As long as it is provided.

  FIG. 2 illustrates the arrangement of the LEDs and the second mirror 107, and is a planar configuration when the LEDs and the second mirror 107 are viewed from the first mirror 103 side. Around the second mirror 107, eight LEDs are arranged at substantially equal intervals. In FIG. 1, two LEDs 101 and 102 that are vertically arranged across the second mirror 107 among the eight LEDs are illustrated. Thus, by arranging a plurality of LEDs around the second mirror 107, the light source device 110 can be made compact. The light source device 110 is not limited to the configuration in which eight LEDs are provided, and the number of LEDs can be determined as appropriate according to the required light amount.

  Returning to FIG. 1, the light from each LED including the LEDs 101 and 102 enters the first mirror 103. The first mirror 103 reflects light from the LED, which is a light source unit, in the direction of the second mirror 107. Since the first mirror 103 is provided with the concave surface facing the LED side, the light reflected by the first mirror 103 converges until it enters the second mirror 107. The second mirror 107 reflects the light from the first mirror 103 and travels toward the opening 105 of the first mirror 103. The light traveling from the second mirror 107 toward the opening 105 passes through the opening 105 and travels toward the rod integrator 120 that is a predetermined direction.

  Since the second mirror 107 is provided with the convex surface facing the first mirror 103 side, the light reflected by the second mirror 107 diverges. The light source device 110 emits substantially parallel light in the direction of the rod integrator 120 by diverging the light converged before entering the second mirror 107 until it becomes substantially parallel. The light source device 110 can efficiently guide the light from the LED to the rod integrator 120 by using the first mirror 103 and the second mirror 107. In addition, the 2nd mirror 107 is not restricted to the structure arrange | positioned in the vicinity of LED. The second mirror 107 may be located at a position where the light reflected by the first mirror 103 is incident, and may be disposed at a position closer to the LED or a position farther from the LED as viewed from the first mirror 103. .

  In the first mirror 103 and the second mirror 107, light in any wavelength region is similarly reflected. If light of any wavelength can be made to travel in the same manner, the chromatic aberration of the light source device 110 can be reduced. By reducing the chromatic aberration of the light source device 110, light of any wavelength can be supplied efficiently. Further, by bending the optical path with the first mirror 103 and the second mirror 107, the light source device 110 can be made compact. Furthermore, as described above, the light source device 110 can also be reduced in size by arranging the LEDs around the second mirror 107.

  Accordingly, it is possible to efficiently supply each color light by reducing chromatic aberration, and to achieve an effect that a compact configuration can be obtained. By efficiently supplying each color light from the light source device 110, the projector 100 can realize good color reproducibility. In addition, since the distance between the LED of the light source device 110 and the spatial light modulator 130 can be shortened, the projector 100 can be reduced in size. Since the projector 100 does not need to consider chromatic aberration, the projector 100 can be configured to be simple and easy to manufacture.

  By setting the first mirror 103 and the second mirror 107 to be aspherical curved surfaces, the light source device 110 can reduce spherical aberration. Here, the light source device 110 is not limited to the configuration in which the first mirror 103 and the second mirror 107 are aspherical curved surfaces. By making at least one of the first mirror 103 and the second mirror 107 an aspherical curved surface, the light source device 110 can reduce spherical aberration. The first mirror 103 and the second mirror 107 may be spherical curved surfaces having a predetermined curvature.

  The second mirror 107 is not limited to a curved surface with a convex surface directed to the first mirror 103 side. The light source device 310 illustrated in FIG. 3 includes a curved second mirror 307 with a concave surface directed toward the first mirror 103. Since the second mirror 307 is provided with the concave surface facing the first mirror 103 side, the light reflected by the second mirror 307 converges. The light source device 310 can converge the light traveling in the direction of the rod integrator 120.

  FIG. 4 shows a configuration of a light source device 410 according to the first modification of the present embodiment. The light source device 410 includes a second mirror 407 having a substantially flat planar shape. The first mirror 403 is an aspherical curved surface, similar to the first mirror 103 (see FIG. 1). The first mirror 103 is provided with an opening 105, whereas the first mirror 403 is not provided with an opening. The LEDs 101 and 102 and the first mirror 403 are arranged so that light incident on the first mirror 403 from the LEDs 101 and 102 travels in a direction substantially perpendicular to the direction of the rod integrator 120 which is a predetermined direction. Has been.

  The second mirror 407 is provided at a position where the light reflected by the first mirror 403 enters. In the light source device 410, the second mirror 407 is tilted so that the normal line of the second mirror 407 and the normal line of the first mirror 403 are not parallel to each other. With this configuration, the light from the first mirror 403 travels in a predetermined direction different from the direction of the first mirror 403 after being reflected by the second mirror 407.

  The first mirror 403 is provided with a concave surface facing the LEDs 101 and 102. For this reason, the light reflected by the first mirror 403 is converged until it enters the second mirror 407. The second mirror 407 bends the light from the first mirror 403 as it is and advances it in the direction of the rod integrator 120 which is a predetermined direction. Since the second mirror 407 returns the convergent light from the first mirror 403 as it is, the light traveling in the direction of the rod integrator 120 is converged as it is.

  FIG. 5 shows a configuration of a light source device 510 according to the second modification of the present embodiment. The light source device 510 includes a third mirror 508 in addition to the first mirror 403 and the second mirror 107. The third mirror 508 is a substantially flat plane. The LEDs 101 and 102 and the first mirror 403 are arranged so that light incident on the first mirror 403 from the LEDs 101 and 102 travels in a direction substantially perpendicular to the direction of the rod integrator 120 which is a predetermined direction. Yes.

  The third mirror 508 is provided at a position between the first mirror 403 and the second mirror 107 where the light reflected by the second mirror 107 is incident. In the light source device 510, the third mirror 508 is tilted so that the normal line of the third mirror 508 and the normal line of the second mirror 107 do not become parallel to each other. With this configuration, the light from the second mirror 107 travels in a predetermined direction different from the direction of the second mirror 107 after being reflected by the third mirror 508.

  The light reflected by the first mirror 403 enters the third mirror 508 after being reflected by the second mirror 107. The third mirror 508 bends the light from the second mirror 107 as it is and advances it in the direction of the rod integrator 120 which is a predetermined direction. The light incident on the rod integrator 120 can be converged or collimated according to the shapes of the first mirror 403 and the second mirror 107. In this embodiment, an LED that supplies white light is used as the light source unit. However, instead of the LED that supplies white light, for example, an R light LED that supplies R light and a G light that supplies G light are used. A light LED and a B light LED that supplies B light may be used.

  FIG. 6 shows a schematic configuration of a projector 600 according to Embodiment 2 of the present invention. The same parts as those of the projector 100 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The projector 600 of this embodiment is a so-called three-plate projector that includes three spatial light modulators 130R, 130G, and 130B. The projector 600 includes an R light source device 110R, a G light source device 110G, and a B light source device 110B.

  The light source device for R light 110R, the light source device for G light 110G, and the light source device for B light 110B all have the same configuration as the light source device 110 of Embodiment 1 (see FIG. 1). The light source device 110R for R light includes an LED 101R for R light that supplies R light as a light source unit. The R light from the R light source device 110R passes through the rod integrator 120R and then enters the spatial light modulator 130R. The spatial light modulator 130R modulates the R light from the R light source device 110R according to the image signal. The light modulated by the spatial light modulator 130R enters the cross dichroic prism 135.

  The G light source device 110G includes a G light LED 101G that supplies G light as a light source unit. The G light from the G light source device 110G passes through the rod integrator 120G and then enters the spatial light modulator 130G. The spatial light modulator 130G modulates the G light from the G light source device 110G according to the image signal. The light modulated by the spatial light modulator 130G enters the cross dichroic prism 135 from a surface different from the R light.

  The light source device 110B for B light includes a B light LED 101B that supplies B light as a light source unit. The B light from the B light source device 110B passes through the rod integrator 120B and then enters the spatial light modulator 130B. The spatial light modulator 130B modulates the B light from the B light source device 110B according to the image signal. The light modulated by the spatial light modulator 130B enters the cross dichroic prism 135 from a different surface from the R light and G light.

  The cross dichroic prism 135 is configured by arranging a first dichroic film 135a and a second dichroic film 135b in an X shape. The first dichroic film 135a reflects R light and transmits G light and B light. The second dichroic film 135b reflects B light and transmits G light and R light. The R light incident on the cross dichroic prism 135 is reflected by the first dichroic film 135 a and travels in the direction of the projection optical system 140.

  The G light incident on the cross dichroic prism 135 passes through the first dichroic film 135a and the second dichroic film 135b and travels straight in the direction of the projection optical system 140. The B light incident on the cross dichroic prism 135 is reflected by the second dichroic film 135 b and travels toward the projection optical system 140. The cross dichroic prism 135 synthesizes each color light in this way.

  By using the light source devices 110R, 110G, and 110B for each color light, the projector 600 can achieve good color reproducibility as well as the projector 100 of the first embodiment, and the projector 100 can be downsized. Furthermore, since each color light source device 110R, 110G, 110B can efficiently supply light of any wavelength, it is possible to use optical systems having substantially the same configuration for each color light. Thus, the projector 600 can be configured to be simple and easy to manufacture. Each color light source device 110R, 110G, 110B may have the same configuration as the light source device 110 described above, or may have the same configuration as the other light source devices of the first embodiment.

  FIG. 7 shows a schematic configuration of a projector 700 according to Embodiment 3 of the present invention. The same parts as those of the projector 100 of the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The light source device 710 has the same configuration as the light source device 110 (see FIG. 1) of the first embodiment. The light source device 710 includes, as a light source unit, an R light LED 101R, a G light LED 101G, and a B light LED (not shown). The light from the light source device 710 passes through the rod integrator 120 and then enters the spatial light modulator 730.

  The spatial light modulator 730 is a tilt mirror device that modulates each color light from the light source device 710 according to an image signal. One example of a tilt mirror device is the DMD® from Texas Instruments. The projector 700 sequentially supplies the R light, the G light, and the B light from the light source device 710 so as to sequentially modulate the R light, the G light, and the B light using the single spatial light modulation device 730. The light source device 710 sequentially turns on the R light LED 101R, the G light LED 101G, and the B light LED so as to sequentially supply R light, G light, and B light. The light modulated by the spatial light modulator 730 enters the projection optical system 140. By using the light source device 710, the projector 700 can achieve good color reproducibility and can be downsized as in the projector 100 of the first embodiment.

  The projectors of the above embodiments may use a transmissive liquid crystal display device or a tilt mirror device as the spatial light modulator, for example, a reflective liquid crystal display device. The projector is not limited to a so-called front projection type projector that observes an image by observing light reflected by the screen 150. The present invention can also be applied to a so-called rear projector that supplies light to one surface of a screen and observes an image by observing light emitted from the other surface of the screen. Moreover, although the light source device of each said Example uses LED as a light source part, it is not restricted to this. Instead of the LED, other solid light emitting elements such as an EL element and a semiconductor laser may be used.

  As described above, the light source device according to the present invention is useful as a light source device for a projector, and is particularly suitable when a plurality of solid state light emitting elements are used.

1 is a schematic configuration diagram of a projector according to a first embodiment of the invention. The figure explaining arrangement | positioning of LED and a 2nd mirror. Explanatory drawing of the structure which provides the 2nd mirror by which the concave surface was turned to the 1st mirror side. FIG. 6 is a schematic configuration diagram of a light source device according to a first modification of the first embodiment. FIG. 6 is a schematic configuration diagram of a light source device according to a second modification of the first embodiment. FIG. 6 is a schematic configuration diagram of a projector according to a second embodiment of the invention. FIG. 6 is a schematic configuration diagram of a projector according to a third embodiment of the invention.

Explanation of symbols

  100 projector, 101, 102 LED, 103 first mirror, 105 aperture, 107 second mirror, 110 light source device, 120 rod integrator, 130 spatial light modulator, 140 projection optical system, 150 screen, AX optical axis, 307 2nd mirror, 310 light source device, 403 1st mirror, 407 2nd mirror, 410 light source device, 508 3rd mirror, 510 light source device, 600 projector, LED for 101R R light, LED for 101G G light , 101B B light LED, 110R R light source device, 110G G light source device, 110B B light source device, 120R, 120G, 120B rod integrator, 130R, 130G, 130B spatial light modulator, 135 cross dichroic prism , 13 a, 135b dichroic film, 700 a projector, 710 light source device, 730 a spatial light modulator

Claims (8)

A light source unit for supplying light;
A first mirror provided with a concave surface facing the light source part;
A second mirror provided opposite to the first mirror,
The first mirror reflects light from the light source unit toward the second mirror,
The light source device, wherein the second mirror reflects the light from the first mirror and emits the light in a predetermined direction.   The light source device according to claim 1, wherein the first mirror has an opening through which the light reflected by the second mirror passes.   The light source device according to claim 1, wherein the second mirror is a curved surface having a convex surface directed toward the first mirror.   The light source device according to claim 1, wherein the second mirror is a curved surface having a concave surface directed toward the first mirror.   The light source device according to claim 1, wherein the second mirror is a substantially flat plane.   6. The light source device according to claim 1, wherein at least one of the first mirror and the second mirror is an aspherical curved surface.   The light source device according to any one of claims 1 to 6, further comprising a third mirror that reflects light reflected by the second mirror in the predetermined direction. The light source device according to any one of claims 1 to 7,
A spatial light modulator that modulates light from the light source device according to an image signal;
A projection optical system that projects light from the spatial light modulation device.

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