ILLUMINATING DEVICE AND PROJECTOR

Abstract

An illuminating device includes: a lamp device that includes a lamp body, which is a light source, and a concave reflector for reflecting light emitted from the lamp body; and a lens member that has a planar optical surface and a nonplanar optical surface opposite to the planar optical surface and is provided on an emission side of the lamp device. In the illuminating device, the lens member is arranged such that a normal line of the planar optical surface is slightly inclined at a predetermined angle with respect to an optical axis of the lamp device. The lens member is arranged such that light beams substantially parallel to the optical axis are incident on the planar optical surface, and a filter that reflects at least one of an ultraviolet ray and an infrared ray is provided on the planar optical surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers refer like elements.

FIG. 1 is a diagram illustrating an optical system of a projector according to a first embodiment of the invention.

FIG. 2A is a cross-sectional view illustrating a light source lamp unit provided in the projector shown in FIG. 1.

FIG. 2B is a diagram illustrating a concave lens 23 that has a normal line H of a planar surface 23b inclined at a very small angle of a with respect to a lamp axis OA.

FIG. 3 is a perspective view illustrating the light source lamp unit provided in the projector shown in FIG. 1.

FIG. 4 is a graph illustrating the relationship between the angle α and reduction in the temperature of a light emitting portion 81 of a lamp body 21.

FIG. 5 is a diagram illustrating an optical system of the main part of a projector according to a second embodiment of the invention.

FIG. 6 is a diagram illustrating an optical system of the main part of a projector according to a third embodiment of the invention.

Claims

1. An illuminating device comprising: a lamp device that includes a lamp body, which is a light source, and a concave reflector that reflects light emitted from the lamp body; anda lens member that has a planar optical surface and a nonplanar optical surface opposite to the planar optical surface and is provided on an emission side of the lamp device,wherein the lens member is arranged such that a normal line of the planar optical surface is slightly inclined at a predetermined angle with respect to an optical axis of the lamp device,the lens member is arranged such that light beams substantially parallel to the optical axis are incident on the planar optical surface, anda filter that reflects at least one of an ultraviolet ray and an infrared ray is provided on the planar optical surface.

2. The illuminating device according to claim 1, wherein the concave reflector is an ellipsoidal reflector that reflects the light emitted from the lamp body to converge,the lens member is a lens that collimates the light reflected from the ellipsoidal reflector,the nonplanar optical surface of the lens member is a concave surface, andthe concave surface is arranged closer to the ellipsoidal reflector than the planar optical surface.

3. The illuminating device according to claim 1, wherein the concave reflector is a paraboloidal reflector that reflects the light emitted from the lamp body to travel as parallel light,the lens member is a lens that condenses the parallel light reflected from the paraboloidal reflector,the nonplanar optical surface of the lens member is a convex surface, andthe planar optical surface is arranged closer to the paraboloidal reflector than the convex optical surface.

4. The illuminating device according to claim 1, further comprising: a plano-convex lens provided on an emission side of the concave reflector,wherein the concave reflector is a paraboloidal reflector that reflects the light emitted from the lamp body to travel as parallel light,the plano-convex lens condenses the parallel light reflected from the paraboloidal reflector,the lens member is a lens that collimates the light condensed by the plano-convex lens, and is arranged on an emission side of the plano-convex lens,the nonplanar optical surface of the lens member is a concave surface, andthe concave surface is arranged closer to the plano-convex lens than the planar optical surface.

5. The illuminating device according to claim 1, wherein the predetermined angle is in a range of 1° to 13°.

6. The illuminating device according to claim 1, further comprising: a housing that holds the lamp device and the lens member and shields a space between the lamp device and the lens member from the outside.

7. A projector comprising: the illuminating device according to claim 1;a light modulating device that modulates illumination light emitted from the illuminating device to form an optical image; anda projection optical system that projects the optical image formed by the light modulating device.

8. The projector according to claim 7, wherein the concave reflector is an ellipsoidal reflector that reflects the light emitted from the lamp body to converge,the lens member is a lens that collimates the light reflected from the ellipsoidal reflector,the nonplanar optical surface of the lens member is a concave surface, andthe concave surface is arranged closer to the ellipsoidal reflector than the planar optical surface.

9. The projector according to claim 7, wherein the concave reflector is a paraboloidal reflector that reflects the light emitted from the lamp body to travel as parallel light,the lens member is a lens that condenses the parallel light reflected from the paraboloidal reflector,the nonplanar optical surface of the lens member is a convex surface, andthe planar optical surface is arranged closer to the paraboloidal reflector than the convex optical surface.

10. The projector according to claim 7, further comprising: a piano-convex lens provided on an emission side of the concave reflector,wherein the concave reflector is a paraboloidal reflector that reflects the light emitted from the lamp body to travel as parallel light,the plano-convex lens condenses the parallel light reflected from the paraboloidal reflector,the lens member is a lens that collimates the light condensed by the plano-convex lens, and is arranged on an emission side of the plano-convex lens,the nonplanar optical surface of the lens member is a concave surface, andthe concave surface is arranged closer to the plano-convex lens than the planar optical surface.

11. The projector according to claim 7, wherein the predetermined angle is in a range of 1° to 13°.

12. The projector according to claim 7, further comprising: a housing that holds the lamp device and the lens member and shields a space between the lamp device and the lens member from the outside.