JP2009180968A - Light source device and projector - Google Patents

Abstract

To provide a light source device and a projector that can be made thin and can efficiently supply light to an irradiated surface.
A light emitting unit 12 that is disposed on a central axis AX and emits light, and a first reflecting unit that is provided around the central axis AX and reflects light emitted from the light emitting unit 12 toward an irradiated surface. The reflector 13 is opposed to the first reflecting part with the light emitting part 12 interposed therebetween, the secondary mirror 14 is a second reflecting part provided around the central axis AX, and the surface to be irradiated with respect to the second reflecting part And a cone mirror 15 that is a third reflecting portion provided around the central axis AX, and the third reflecting portion becomes gradually thinner toward the irradiated surface side on the central axis AX. The shape which becomes.
[Selection] Figure 1

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 reflector.

  In order to improve portability and ease of installation, the projector is required to be thin. 2. Description of the Related Art Conventionally, a reflector that reflects light emitted from a light emitting unit is used in a lamp used as a light source of a projector, for example, a discharge lamp such as an ultra-high pressure mercury lamp. In order to efficiently transmit light to the surface to be irradiated, many reflectors form a rotating curved surface, for example, a rotating ellipsoid obtained by rotating an ellipse, or a rotating paraboloid obtained by rotating a parabola. The shape is adopted. The reflector needs to have a sufficient size in order to efficiently propagate light to the irradiated surface. For this reason, in the illumination optical system of the projector, in particular, the reflector often becomes an obstacle to making the projector thinner. A light source device including a reflector is required to be able to efficiently supply light to an irradiated surface and be thin. Conventionally, for example, Patent Document 1 proposes a technique for enabling a light source device including a reflector to be thinned. The technique proposed in Patent Document 1 is to reduce the thickness of the light source device by using a cylindrical reflector. By providing a plurality of reflecting surfaces formed along the circumferential direction of the cylindrical body on the inner surface of the reflector, light is condensed at a position on the central axis.

JP 2007-93989 A

  The reflecting surface for condensing light at a position on the central axis is provided on the surface of a corrugated structure, for example, a Fresnel-shaped structure provided in a Fresnel lens. The Fresnel-shaped structure has a backward surface provided between the reflecting surfaces. The backward surface is formed along the circumferential direction of the cylindrical body, similarly to the reflective surface. A part of the light emitted from the light emitting unit is incident on the rear surface directly from the light emitting unit or after being reflected by the reflecting surface. The light incident on the backward surface travels in a direction different from the direction of the irradiated surface. For this reason, according to the conventional technique, there arises a problem that it is difficult to efficiently supply light to the irradiated surface. SUMMARY An advantage of some aspects of the invention is that it provides a light source device and a projector that can be thinned and can efficiently supply light to an irradiated surface.

  In order to solve the above-described problems and achieve the object, a light source device according to the present invention is disposed on a central axis, and emits light from the light emitting unit that is disposed around the central axis and is emitted from the light emitting unit. A first reflecting portion that reflects light toward the irradiated surface, a second reflecting portion that is opposed to the first reflecting portion with the light emitting portion interposed therebetween, and that is provided around the central axis, and the second reflecting portion A third reflecting portion which is provided on the irradiated surface side and is provided with the central axis as a center, and the third reflecting portion has a shape that becomes gradually narrower toward the irradiated surface side on the central axis. It is characterized by.

  The light traveling from the light emitting unit toward the second reflecting unit is reflected by the second reflecting unit and proceeds toward the first reflecting unit. The light source device reflects light emitted from the light emitting unit in a direction other than the first reflecting unit by the second reflecting unit, so that the light emitted from the light emitting unit in the direction other than the first reflecting unit is changed to the first reflecting unit. It can be efficiently used to advance to the irradiated surface. The light that travels directly from the light emitting part or from the light emitting part through the second reflecting part toward the first reflecting part is reflected by the first reflecting part. Of the light reflected by the first reflecting portion, the light traveling in the direction of the third reflecting portion is reflected by the third reflecting portion and travels in the direction of the irradiated surface. By using the third reflecting portion having a shape that gradually becomes thinner toward the irradiated surface side, the light traveling from the first reflecting portion toward the third reflecting portion can be efficiently advanced toward the irradiated surface. it can. By using the second reflecting portion and the third reflecting portion, it is possible to efficiently advance light to the irradiated surface when the first reflecting portion is made thin. Thereby, it is possible to obtain a light source device that can be made thin and can efficiently supply light to the irradiated surface.

  Moreover, as a preferable aspect of the present invention, it is desirable that the third reflecting portion has substantially the same shape as the side surface of the cone. Thereby, a 3rd reflection part provided with the shape which becomes gradually thin as it goes to the irradiated surface side can be obtained.

  Moreover, as a preferable aspect of the present invention, it is desirable that the second reflecting portion and the third reflecting portion are configured integrally. Thereby, the loss of light due to light entering between the second reflecting portion and the third reflecting portion can be reduced.

  Moreover, as a preferable aspect of the present invention, when the specific direction substantially orthogonal to the central axis is the first direction, and the central axis and the direction substantially orthogonal to the first direction are the second direction, the first reflecting portion is the central axis. It is desirable to provide a shape that is long in the second direction with respect to the first direction in a plane substantially orthogonal to the first direction. Thereby, a light source device can be made thin.

  Moreover, as a preferable aspect of the present invention, it is desirable that the first reflecting portion has a substantially elliptical shape on a surface substantially orthogonal to the central axis. Thereby, a 1st reflection part provided with a shape long in the 2nd direction to the 1st direction is obtained.

  Moreover, as a preferable aspect of the present invention, it is desirable that the first reflecting portion includes a plane portion substantially parallel to the central axis and the second direction. Thereby, a 1st reflection part provided with a shape long in the 2nd direction to the 1st direction is obtained.

  As a preferred aspect of the present invention, when the specific direction substantially orthogonal to the central axis is the first direction and the central axis and the direction substantially orthogonal to the first direction are the second direction, the third reflecting portion is the central axis. It is desirable to provide a shape that is long in the second direction with respect to the first direction in a plane substantially orthogonal to the first direction. Thereby, the light from a 1st reflection part provided with a shape long in a 2nd direction with respect to a 1st direction can be efficiently advanced to the direction of a to-be-irradiated surface.

  Furthermore, a projector according to the present invention includes the light source device described above and a spatial light modulation device that modulates light emitted from the light source device in accordance with an image signal. By using the light source device described above, light can be efficiently supplied to the irradiated surface of the spatial light modulator by the thin light source device. As a result, it is possible to obtain a thin projector that can efficiently display a bright image.

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

  FIG. 1 shows a perspective configuration of a light source device 10 according to Embodiment 1 of the present invention. The light source device 10 includes an arc tube 11. The arc tube 11 is, for example, an ultra high pressure mercury lamp. The arc tube 11 includes a light emitting unit 12 that emits light. The light emitting unit 12 is disposed on the central axis AX of the light source device 10. The X axis is an axis orthogonal to the central axis AX. The Y axis is an axis orthogonal to the central axis AX and the X axis. The Z axis is an axis parallel to the central axis AX.

  The reflector 13 is provided around the central axis AX. The reflector 13 functions as a first reflecting unit that reflects light emitted from the light emitting unit 12 toward an irradiated surface (not shown). The irradiated surface is provided at a position where light traveling from the light source device 10 in the arrow direction of the Z axis in the figure enters. The arrow direction of the Z axis is the traveling direction of light from the light source device 10 toward the irradiated surface. The reflector 13 has a concave shape including an opening directed to the side from which light is emitted from the light source device 10 toward the irradiated surface.

  The sub mirror 14 is provided on the irradiated surface side with respect to the light emitting unit 12 and in the vicinity of the light emitting unit 12. The secondary mirror 14 is provided with the side opposite to the irradiated surface side facing the reflector 13 facing the irradiated surface side. The secondary mirror 14 is opposed to the reflector 13 with the light emitting unit 12 interposed therebetween, and functions as a second reflecting unit provided around the central axis AX. The cone mirror 15 functions as a third reflecting portion that is on the irradiated surface side with respect to the secondary mirror 14 and is provided around the central axis AX.

  FIG. 2 shows a YZ plane configuration of the light source device 10. In the drawing, the reflector 13 is shown in a cross section including the central axis AX. In the cross section shown in the figure, the reflector 13 has substantially the same shape as a part of an ellipse having a long axis substantially parallel to the central axis AX. The light emitting unit 12 is disposed at a first focal point which is one of focal points defining such an ellipse. The reflector 13 condenses light at the second focal point of the ellipse in the YZ plane. In the XZ plane, the reflector 13 has substantially the same shape as a part of an ellipse having a long axis substantially parallel to the central axis AX. The ellipse in the XZ plane has a different shape from the ellipse in the YZ plane. The second focal point of the ellipse in the YZ plane is a position closer to the light emitting unit 12 than the second focal point of the ellipse in the XZ plane. The reflector 13 can be formed by applying a dielectric multilayer film or a metal film, which is a highly reflective member, to the surface on the central axis AX side of the concavely shaped base material. The base material of the reflector 13 is comprised using heat resistant glass, for example.

  FIG. 3 shows an XY plane configuration of the reflector 13 on the side where the opening is provided. The XY plane is a plane substantially orthogonal to the central axis AX. The reflector 13 has a substantially elliptical shape in which the major axis is substantially parallel to the X axis and the minor axis is substantially parallel to the Y axis in the illustrated plane. In the XY plane, the reflector 13 has a shape that is longer in the X-axis direction that is the second direction than the Y-axis direction that is the first direction. On the other hand, a reflector having a rotationally curved surface such as a spheroid has a substantially circular shape on the XY plane. The reflector 13 having an elliptical shape in the XY plane can reduce the width in the Y-axis direction as compared with the case of forming a rotating curved surface. Since the width of the reflector 13 in the Y-axis direction can be reduced, the light source device 10 can be made thinner as compared with the case of using a reflector having a rotating curved surface. The light source device 10 can advance a large amount of light to the irradiated surface by ensuring a sufficient diameter of the reflector 13 in the X-axis direction.

  FIG. 4 shows a perspective configuration of the arc tube 11 and the cone mirror 15 in the light source device 10. The conical mirror 15 has substantially the same shape as the conical surface of the conical cone. A conical surface is a side surface of a cone. If a circular plane of the cone is a bottom surface, the side surface is a surface other than the bottom surface of the cone. The cone mirror 15 has a shape that becomes gradually thinner toward the irradiated surface side on the central axis AX. The cone mirror 15 is provided with a dielectric multilayer film or a metal film, which is a highly reflective member, on the surface opposite to the central axis AX side. The cone mirror 15 is a portion corresponding to the bottom surface of the cone, and is disposed so as to cover nearly half of the light emitting unit 12 on the irradiated surface side. The secondary mirror 14 (not shown) is covered with the cone mirror 15. A space for arranging a part of the arc tube 11 and the sub mirror 14 is formed on the side of the central axis AX in the cone mirror 15.

  FIG. 5 shows a YZ cross-sectional configuration of a portion of the light source device 10 where the sub mirror 14 and the cone mirror 15 are provided. The YZ cross section shown includes a central axis AX. The secondary mirror 14 is fixed to the arc tube 11 using, for example, an adhesive. The sub mirror 14 is attached so as to cover nearly half of the light emitting unit 12 on the irradiated surface side. For example, the secondary mirror 14 has the same shape as a part of a spherical surface whose center is the light emission center in the light emitting unit 12. The secondary mirror 14 is configured using a highly reflective member, for example, a metal member. The base material of the secondary mirror 14 is made of quartz, neoceram, which are low thermal expansion materials, or translucent alumina, sapphire, quartz, fluorite, YAG, etc., which are high thermal conductivity materials. In addition to being attached to the outside of the light emitting unit 12, the sub mirror 14 may be obtained by directly depositing a dielectric multilayer film or a metal film, which is a highly reflective member, on the light emitting unit 12. The sub mirror 14 and the cone mirror 15 may be configured integrally. By eliminating the gap between the secondary mirror 14 and the cone mirror 15, it is possible to reduce the loss of light due to light entering between the cone mirror 25 and the secondary mirror 14.

  FIG. 6 illustrates the behavior of light incident on the secondary mirror 14 from the light emitting unit 12. The light emitted from the light emitting unit 12 to the irradiated surface side enters the secondary mirror 14. The light incident on the secondary mirror 14 from the light emitting unit 12 is reflected by the secondary mirror 14 and then travels toward the reflector 13 (see FIG. 2) through the light emission center of the light emitting unit 12. Temporarily, when it is set as the structure which combined only the reflector 13 with the arc_tube | light_emitting_tube 11, it will become difficult to advance the light radiated | emitted from the light emission part 12 to directions other than the reflector 13 to the direction of an irradiated surface efficiently. The light source device 10 reflects the light emitted from the light emitting unit 12 in a direction other than the reflector 13 by the sub mirror 14, thereby efficiently using the reflector 13 to emit the light emitted from the light emitting unit 12 in the direction other than the reflector 13. It can be advanced to the surface to be irradiated.

  FIG. 7 illustrates the behavior of light emitted from the light emitting unit 12. Here, a description will be given assuming that light emitted from the light source device 10 is incident on the concave lens 18. The optical axis of the concave lens 18 substantially coincides with the central axis AX of the light source device 10. The light emitted from the light emitting unit 12 to the side opposite to the irradiated surface side proceeds directly from the light emitting unit 12 to the reflector 13. The light that travels in the direction of the reflector 13 directly from the light emitting unit 12 or through the secondary mirror 14 (see FIG. 6) from the light emitting unit 12 is reflected by the reflector 13. A part of the light reflected by the reflector 13 travels from the reflector 13 toward the irradiated surface. Of the light reflected by the reflector 13, the light traveling in the direction of the cone mirror 15 is reflected by the cone mirror 15 and travels in the direction of the irradiated surface.

  The reflector 13 has a shape that is long in the X-axis direction with respect to the Y-axis direction, so that the reflector 13 moves closer to the light emitting unit 12 in the central axis AX than in the case of a shape that forms a rotating curved surface. The light that goes will increase. The closer the position at which the light beam from the reflector 13 intersects the central axis AX is closer to the light emitting unit 12, the greater the angle between the light beam from the reflector 13 and the central axis AX. If a configuration in which only the reflector 13 is combined with the arc tube 11 is provided, the light that is not taken into the concave lens 18 increases as the light beam having a larger angle with the central axis AX increases, as indicated by the dashed arrow in the figure. It will be. By arranging the concave lens 18 as close as possible to the light source device 10 and increasing the size of the concave lens 18, it is possible to increase the light that can be captured by the concave lens, while reducing the distance between the light source device 10 and the concave lens 18. There is a limit to increasing the size of the concave lens 18. Further, in the case where only the reflector 13 is combined with the arc tube 11, the light traveling from the reflector 13 toward the light emitting unit 12 is scattered by the light emitting unit 12. It is difficult for the light scattered by the light emitting unit 12 to efficiently travel in the direction of the irradiated surface.

  In the light source device 10 of the present invention, by providing the cone mirror 15, the light traveling from the reflector 13 toward the position near the light emitting unit 12 in the central axis AX can be advanced toward the irradiated surface. The cone mirror 15 has a function of reducing the angle formed by the light beam and the central axis AX by making the shape gradually narrower toward the irradiated surface side. By reducing the angle formed between the light beam and the central axis AX, the light reflected by the cone mirror 15 can be efficiently advanced to the concave lens 18. Further, by covering nearly half of the light emitting unit 12 on the irradiated surface side with the cone mirror 15, most of the light traveling from the reflector 13 to the light emitting unit 12 can be reflected by the cone mirror 15. Therefore, it is possible to suppress the light traveling from the reflector 13 to the light emitting unit 12 from being scattered by the light emitting unit 12.

  As described above, the light source device 10 can efficiently make light incident on the concave lens 18 using the thin reflector 13, the secondary mirror 14, and the cone mirror 15. By making light incident on the concave lens 18 efficiently, the light can efficiently travel to the irradiated surface. As a result, it is possible to reduce the thickness and efficiently supply light to the irradiated surface.

  FIG. 8 shows an XY plane configuration on the side where the opening is provided in the reflector 20 according to the modification of the present embodiment. The reflector 20 according to this modification can be applied to the light source device 10 described above. The reflector 20 according to this modification is configured by combining two curved surface portions 21 and 22 and two flat surface portions 23 and 24. The reflector 20 functions as a first reflecting unit that reflects light emitted from the light emitting unit 12 (see FIG. 2) toward an irradiated surface (not shown).

  The curved surface portions 21 and 22 have substantially the same shape as a part of the rotational curved surface S1 obtained by rotating the curve around the central axis AX. The rotating curved surface S1 is, for example, a rotating ellipsoid obtained by rotating a part of an ellipse. The rotating curved surface S1 forms a circle on the XY plane shown in the figure. The 1st plane part 23 and the 2nd plane part 24 have a plane located in the center axis | shaft AX side with respect to parts other than the part in which the curved surface parts 21 and 22 were provided among rotation curved surface S1. The reflector 20 can efficiently propagate the light reflected by the curved surface portions 21 and 22 having substantially the same shape as a part of the rotating curved surface S1 toward the irradiated surface.

  The first plane part 23 and the second plane part 24 are plane parts substantially parallel to the central axis AX and the X-axis direction that is the second direction. The first plane part 23 and the second plane part 24 are opposed to each other via the central axis AX. The reflector 20 has a shape that is longer in the X-axis direction, which is the second direction, than the Y-axis direction, which is the first direction, on the XY plane that is substantially orthogonal to the central axis AX. The reflector 20 can be made thinner by providing the first flat surface portion 23 and the second flat surface portion 24 facing each other as compared with the case where only the shape substantially the same as the rotational curved surface S1 is used. Also in this modified example, the light incident on the cone mirror 15 (see FIG. 2) from the first plane part 23 and the second plane part 24 can be efficiently advanced in the direction of the irradiated surface.

  The reflector 20 is not limited to one having two flat portions facing each other. The reflector 20 only needs to have at least one plane portion. By providing at least one plane portion, it is possible to obtain an effect of making the reflector 20 thinner as compared with the case where only the shape substantially the same as that of the rotating curved surface S1 is used. Further, the reflector 20 is not limited to the one having the curved surface portions 21 and 22 having substantially the same shape as a part of the rotating curved surface S1. For example, the reflector 20 may have a curved surface portion having substantially the same shape as a part of a curved surface having an elliptical shape on the XY plane.

  The light source device 10 according to the present embodiment is not limited to the case where the reflectors 13 and 20 are long in the X-axis direction with respect to the Y-axis direction on the XY plane. The light source device 10 may use a reflector that is miniaturized in the Y-axis direction and the X-axis direction. Therefore, the reflector may have a shape with substantially the same length in the Y-axis direction and the X-axis direction on the XY plane, or may have a shape whose X-axis direction is shorter than the Y-axis direction. Even when the reflector is downsized not only in the Y-axis direction but also in the X-axis direction, the light source device 10 can efficiently supply light to the irradiated surface by using the secondary mirror 14 and the cone mirror 15. .

  FIG. 9 shows a perspective configuration of a cone mirror 25 according to a modification of the present embodiment and a connecting mirror 26 connected to the cone mirror 25. The cone mirror 25 and the connection mirror 26 according to this modification can be applied to the light source device 10 described above. The cone mirror 25 functions as a third reflecting portion provided on the irradiated surface side with respect to the secondary mirror 14 (not shown) (see FIG. 5) and provided around the central axis AX.

  The cone mirror 25 has substantially the same shape as the side surface of the elliptic cone, which is a cone whose bottom surface is elliptical. The cone mirror 25 has a shape that becomes gradually thinner toward the irradiated surface side on the central axis AX. Further, the elliptical shape included in the cone mirror 25 and the elliptical shape included in the XY plane configuration of the reflector 13 (see FIG. 3) are substantially similar to each other. The cone mirror 25 has a shape that is long in the X-axis direction, which is the second direction, with respect to the Y-axis direction, which is the first direction, in the XY plane that is substantially orthogonal to the central axis AX. By using the cone mirror 25 having such a shape, light traveling from the reflector 13 toward the cone mirror 25 can efficiently travel toward the irradiated surface. The shape of the cone mirror 25 may be appropriately changed according to the shape of the reflector 13.

  The connection mirror 26 connects the secondary mirror 14 (not shown) and the cone mirror 25. The connection mirror 26 reflects light incident on the connection mirror 26 from the reflector 13. The connection mirror 26 is provided around the central axis AX, and a highly reflective member is provided on the surface opposite to the central axis AX side. The end of the connecting mirror 26 on the cone mirror 25 side has an elliptical shape that is substantially the same as the elliptical shape of the cone mirror 25. In the connection portion of the cone mirror 25 and the connection mirror 26, the width n1 in the X-axis direction is larger than the width m1 in the Y-axis direction.

An opening is formed on the connection mirror 26 on the side opposite to the cone mirror 25 side. The opening has a circular shape that is substantially the same as the circular shape of the secondary mirror 14. The secondary mirror 14 is fitted into the opening of the connection mirror 26. The width m2 of the opening in the Y-axis direction and the width n2 in the X-axis direction are substantially equal. The width m1 in the Y-axis direction of the connection portion of the cone mirror 25 and the connection mirror 26 is substantially equal to the width m2 of the opening in the Y-axis direction. Therefore, the following relationship holds.
n1> m1 = n2 = m2

  Thus, the cone mirror 25 and the secondary mirror 14 are integrally configured via the connection mirror 26. By adopting a configuration in which the cone mirror 25 and the secondary mirror 14 are connected by the connection mirror 26, it is possible to reduce light loss due to light entering between the cone mirror 25 and the secondary mirror 14. Note that the configuration in which the cone mirror 25 and the sub mirror 14 are integrated is not limited to the case of using the connection mirror 26 described in the present modification, and can be appropriately modified.

  FIG. 10 shows a schematic configuration of a projector 60 according to Embodiment 2 of the present invention. The projector 60 is a front projection type projector that projects light onto a screen (not shown) and observes an image by observing light reflected from the screen. The projector 60 includes the light source device 10 according to the first embodiment. The light source device 10 emits light including red (R) light, green (G) light, and blue (B) light. The concave lens 18 collimates the light emitted from the light source device 10. The first integrator lens 61 and the second integrator lens 62 have a plurality of lens elements arranged in an array. The first integrator lens 61 divides the light beam from the concave lens 18 into a plurality of parts. Each lens element of the first integrator lens 61 condenses the light beam from the concave lens 18 in the vicinity of the lens element of the second integrator lens 62. The lens element of the second integrator lens 62 forms an image of the lens element of the first integrator lens 61 on the spatial light modulator.

  Light that has passed through the two integrator lenses 61 and 62 is converted into linearly polarized light in a specific vibration direction by the polarization conversion element 63. The superimposing lens 64 superimposes the image of each lens element of the first integrator lens 61 on the spatial light modulator. The first integrator lens 61, the second integrator lens 62, and the superimposing lens 64 make the intensity distribution of light from the light source device 10 uniform on the spatial light modulator. The light from the superimposing lens 64 enters the first dichroic mirror 65. The first dichroic mirror 65 reflects R light and transmits G light and B light. The R light incident on the first dichroic mirror 65 has its optical path bent by the first dichroic mirror 65 and the reflection mirror 66, and enters the R light field lens 67R. The R light field lens 67R collimates the R light from the reflection mirror 66 and makes it incident on the R light spatial light modulator 68R.

  The spatial light modulator 68R for R light is a spatial light modulator that modulates R light according to an image signal, and is a transmissive liquid crystal display device. A liquid crystal panel (not shown) provided in the R light spatial light modulation device 68R encloses a liquid crystal layer for modulating light according to an image signal between two transparent substrates. The R light modulated by the R light spatial light modulator 68R is incident on a cross dichroic prism 69 which is a color synthesis optical system.

  The G light and B light that have passed through the first dichroic mirror 65 enter the second dichroic mirror 70. The second dichroic mirror 70 reflects G light and transmits B light. The G light incident on the second dichroic mirror 70 has its optical path bent by the second dichroic mirror 70 and is incident on the G light field lens 67G. The G light field lens 67G collimates the G light from the second dichroic mirror 70 and makes it incident on the G light spatial light modulator 68G. The G light spatial light modulator 68G is a spatial light modulator that modulates the G light according to an image signal, and is a transmissive liquid crystal display device. The G light modulated by the G light spatial light modulator 68G is incident on a different surface of the cross dichroic prism 69 from the surface on which the R light is incident.

  The B light transmitted through the second dichroic mirror 70 is transmitted through the relay lens 71, and then the optical path is bent by reflection at the reflection mirror 72. The B light from the reflection mirror 72 further passes through the relay lens 73, and then the optical path is bent by reflection by the reflection mirror 74, and enters the B light field lens 67B. Since the optical path of the B light is longer than the optical path of the R light and the optical path of the G light, relay lenses 71 and 73 are provided in the optical path of the B light in order to make the illumination magnification in the spatial light modulator equal to that of other color lights. The relay optical system to be used is adopted.

  The B light field lens 67B collimates the B light from the reflection mirror 74 and makes it incident on the B light spatial light modulator 68B. The B light spatial light modulator 68B is a spatial light modulator that modulates B light in accordance with an image signal, and is a transmissive liquid crystal display device. The B light modulated by the B light spatial light modulator 68B is incident on a surface of the cross dichroic prism 69 that is different from the surface on which the R light is incident and the surface on which the G light is incident.

  The cross dichroic prism 69 has two dichroic films 75 and 76 that are substantially orthogonal to each other. The first dichroic film 75 reflects R light and transmits G light and B light. The second dichroic film 76 reflects B light and transmits R light and G light. The cross dichroic prism 69 combines R light, G light, and B light incident from different directions and emits the light toward the projection lens 77. The projection lens 77 projects the light combined by the cross dichroic prism 69 toward the screen.

  By using the light source device 10 described above, the projector 60 can efficiently supply light to the irradiated surfaces of the color light spatial light modulators 68R, 68G, and 68B by the thin light source device 10. Thereby, there is an effect that the projector 60 can be made thin and a bright image can be efficiently displayed. Since the projector 60 can be made thin, it can be excellent in portability and installability.

  The projector 60 according to the present invention is not limited to the case where a transmissive liquid crystal display device is used as the spatial light modulation device. As the spatial light modulator, a reflective liquid crystal display (Liquid Crystal On Silicon; LCOS), DMD (Digital Micromirror Device), GLV (Grating Light Valve), or the like may be used. The projector 60 is not limited to a configuration including a spatial light modulator for each color light. The projector 60 may be configured to modulate two or three or more color lights with one spatial light modulator. The projector 60 is not limited to the case where a spatial light modulator is used. The projector 60 may be a slide projector that uses a slide having image information. The projector 60 may be a so-called rear projector that supplies light to one surface of the screen and observes an image by observing light emitted from the other surface of the screen. The light source device according to the present invention is not limited to that used for the projector 60. The light source device may be applied to, for example, a lighting device such as a flashlight or a headlight of an automobile.

  As described above, the light source device according to the present invention is suitable for use in a projector.

The figure which shows the perspective structure of the light source device which concerns on Example 1 of this invention. The figure which shows the YZ plane structure of a light source device. The figure which shows XY plane structure of the side provided with opening among reflectors. The figure which shows the perspective structure of a light-emitting tube and a cone mirror. The figure which shows the YZ cross-section structure of the part in which the submirror and the cone mirror were provided. The figure explaining the behavior of the light which injected into the secondary mirror from the light emission part. The figure explaining the behavior of the light inject | emitted from the light emission part. The figure which shows the structure of the reflector which concerns on the modification of Example 1. FIG. FIG. 6 is a diagram illustrating a configuration of a cone mirror and a connection mirror according to a modification of the first embodiment. FIG. 5 is a diagram illustrating a schematic configuration of a projector according to a second embodiment of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Light source device, 11 Light emission tube, 12 Light emission part, 13 Reflector, 14 Secondary mirror, 15 Conical mirror, AX Central axis, 18 Concave lens, 20 Reflector, 21, 22 Curved surface part, 23 1st plane part, 24 2nd plane Part, S1 rotating curved surface, 25 cone mirror, 26 connecting mirror, 60 projector, 61 first integrator lens, 62 second integrator lens, 63 polarization conversion element, 64 superimposing lens, 65 first dichroic mirror, 66 reflecting mirror, 67R Field lens for R light, field lens for 67G G light, field lens for 67B B light, spatial light modulation device for 68R R light, spatial light modulation device for 68G G light, spatial light modulation device for 68B B light, 69 cross dichroic Prism, 70 Second dichroic mirror, 71, 73 Rerenzu, 72, 74 reflecting mirror, 75 a first dichroic film, 76 second dichroic film, 77 a projection lens

Claims (8)

A light emitting unit disposed on the central axis and emitting light;
A first reflecting portion provided around the central axis and configured to reflect light emitted from the light emitting portion toward an irradiated surface;
A second reflecting portion provided around the central axis so as to face the first reflecting portion across the light emitting portion;
A third reflecting portion provided on the irradiated surface side with respect to the second reflecting portion and provided around the central axis,
The light source device according to claim 3, wherein the third reflecting portion has a shape that gradually becomes narrower toward the irradiated surface side on the central axis.   The light source device according to claim 1, wherein the third reflecting portion has substantially the same shape as a side surface of the cone.   The light source device according to claim 1, wherein the second reflection unit and the third reflection unit are integrally formed. When a direction substantially orthogonal to the central axis is a first direction, and a direction substantially orthogonal to the central axis and the first direction is a second direction,
The said 1st reflection part is equipped with a shape long in the said 2nd direction with respect to the said 1st direction in the surface substantially orthogonal to the said central axis, The Claim 1 characterized by the above-mentioned. Light source device.   5. The light source device according to claim 4, wherein the first reflecting portion has a substantially elliptical shape on a surface substantially orthogonal to the central axis.   5. The light source device according to claim 4, wherein the first reflecting portion includes a flat portion substantially parallel to the central axis and the second direction. When a specific direction substantially orthogonal to the central axis is a first direction, and a direction substantially orthogonal to the central axis and the first direction is a second direction,
The said 3rd reflection part is provided with a shape long in the said 2nd direction with respect to the said 1st direction in the surface substantially orthogonal to the said center axis | shaft, The any one of Claims 4-6 characterized by the above-mentioned. Light source device. The light source device according to any one of claims 1 to 7,
And a spatial light modulation device that modulates light emitted from the light source device in accordance with an image signal.

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