Optical device, illumination apparatus using the device, and projector using the illumination apparatus

1. An optical device which leads light beams emitted by a light source to a predetermined illumination area, comprising:

a first light leading member including:

a first incident surface configured to be entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface configured to emit the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the first incident surface; and

a second light leading member including:

a second incident surface configured to be entered the light beams emitted from the first outgoing radiation surface of the first light leading member;

a second reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface configured to emit the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface;

wherein the first light leading member relatively swivels with respect to the second light leading member,

a diameter of a circumscribing circle of the first outgoing radiation surface shape in the first light leading member is not more than a diameter of an inscribing circle of the second incident surface shape in the second light leading member, and

a center of swiveling when the first light leading member relatively swivels with respect to the second light leading member is substantially the same as a center of the circumscribing circle and the inscribing circle.

2. The device according to claim 1 , wherein

the first outgoing radiation surface of the first light leading member is opposed to the second incident surface of the second light leading member with a gap therebetween, and

a diameter D 2 of the inscribing circle of the second incident surface shape in the second light leading member is a length satisfying the following expression:

D 2 >D 1 +2 d ×tan θ

where D 1 is a diameter of the circumscribing circle of the first outgoing radiation surface shape in the first light leading member, d is a length of the gap, and θ is a maximum outgoing radiation angle of the light beams on the first outgoing radiation surface of the fist light leading member.

3. The device according to claim 1 , wherein one of the first light leading member and the second light leading member is formed of a solid rod, and the other one of the same is formed of a hollow pipe having a reflection surface on an inner surface thereof.

4. The device according to claim 3 , wherein a distance between the incident surface and the outgoing radiation surface of the light leading member formed of the solid rod is longer than a distance between the incident surface and the outgoing radiation surface of the light leading member formed of the hollow pipe.

5. The device according to claim 1 , wherein the first light leading member has a tapered shape in which the first outgoing radiation surface is larger than the first incident surface, and

the second light leading member also has a tapered shape in which the second outgoing radiation surface is larger than the second incident surface.

6. The device according to claim 1 , wherein

the first light leading member has a tapered shape in which the first outgoing radiation surface is larger than the first incident surface, and

the second light leading member has an inverse-tapered shape in which the second outgoing radiation surface is smaller than the second incident surface.

7. The device according to claim 1 , wherein

the first light leading member has an inverse-tapered shape in which the first outgoing radiation surface is smaller than the first incident surface, and

the second light leading member has a tapered shape in which the second outgoing radiation surface is larger than the second incident surface.

8. The device according to claim 1 , wherein the first outgoing radiation surface of the first light leading member is opposed to the second incident surface of the second light leading member with a gap therebetween.

9. The device according to claim 8 , wherein a minimum dimension D 2 of the second incident surface of the second light leading member is a length satisfying the following expression:

D 2 >D 1 +2 d ×tan θ

where D 1 is a maximum dimension of the first outgoing radiation surface of the first light leading member, d is a length of the gap, and θ is a maximum outgoing radiation angle of light beams on the first outgoing radiation surface of the first light leading member.

10. The device according to claim 9 , wherein

the D 1 is a diameter of a circumscribing circle of the first outgoing radiation surface shape in the first light leading member, and

the D 2 is a diameter of an inscribing circle of the second incident surface shape in the second light leading member.

11. An optical device which leads light beams emitted by a light source to a predetermined illumination area, comprising:

a first light leading member including:

a first incident surface configured to be entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface configured to emit the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the first incident surface; and

a second light leading member including:

a second incident surface configured to be entered the light beams emitted from the first outgoing radiation surface of the first light leading member;

a second reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface configured to emit the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface;

wherein the first incident surface shape in the first light leading member is a quadrangle,

the first outgoing radiation surface shape in the first light leading member is one of a circle and a polygon having five or more angles, and

the first outgoing radiation surface shape in the first light leading member is similar to the second incident surface shape in the second light leading member.

12. An optical device which leads light beams emitted by a light source to a predetermined illumination area, comprising:

a first light leading member including:

a first incident surface configured to be entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface configured to emit the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the first incident surface; and

a second light leading member including:

a second incident surface configured to be entered the light beams emitted from the first outgoing& radiation surface of the first light leading member;

a second reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface configured to emit the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface;

wherein the second outgoing radiation surface shape in the second light leading member is a quandrangle, and

the second incident surface shape in the second light leading member is one of a circle and a polygon having five or more angles.

13. The device according to claim 12 , wherein the first outgoing radiation surface shape in the first light leading member is similar to the second incident surface shape in the second light leading member.

14. An optical device which leads light beams emitted by a light source to a predetermined illumination area, comprising:

a first light leading member including:

a first incident surface configured to be entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface configured to emit the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the first incident surface; and

a second light leading member including:

a second incident surface configured to be entered the light beams emitted from the first outgoing radiation surface of the first light leading member;

a second reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface configured to emit the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface;

wherein the first incident surface shape in the first light leading member and the second outgoing radiation surface shape in the second light leading member are quadrangles.

15. The device according to claim 14 , wherein the first outgoing radiation surface shape in the first light leading member is similar to the second incident surface shape in the second light leading member.

16. A projector comprising:

an illumination apparatus which illuminates a predetermined irradiation target surface, including:

a light source configured to emit light beams;

an optical device which leads light beams emitted by the light source to a predetermined illumination area, comprising:

a first light leading member including:

a first incident surface configured to be entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface configured to emit the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the fist incident surface; and

a second light leading member including:

a second incident surface configured to be entered the light beams emitted from the first outgoing radiation surface of the first light leading member;

a second reflection surface comprising at least one surface configured to reflect a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface configured to emit the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface; and

an illumination optical member configured to have an optically conjugate positional relationship between the second outgoing radiation surface of the second light leading member in the optical device and the predetermined irradiation target surface;

a display device arranged on the irradiation target surface; and

a projection optical system configured to project an image formed by the display device onto a screen,

the light source being an LED which emits light beams from a light emission surface thereof, and

both the first incident surface shape in the first light leading member and light emission surface shape of the LED being quadrangles.

17. A projector comprising:

an illumination apparatus for illuminating a predetermined irradiation target surface, including:

a light source for emitting light beams;

an optical device for leading light beams emitted by the light source to a predetermined illumination area, including:

first light leading means including:

a first incident surface for being entered the light beams emitted by the light source;

a first reflection surface comprising at least one surface for reflecting a part of the light beams which enter the first incident surface; and

a first outgoing radiation surface for emitting the light beams reflected on the first reflection surface and a part of the light beams which enter the first incident surface, the first outgoing radiation surface having a shape different from that of the first incident surface; and

second light leading means including:

a second incident surface for being entered the light beams emitted from the first outgoing radiation surface of the first light leading means;

a second reflection surface comprising at least one surface for reflecting a part of the light beams which enter the second incident surface; and

a second outgoing radiation surface for emitting the light beams reflected on the second reflection surface and a part of the light beams which enter the second incident surface, the second outgoing radiation surface having a shape different from that of the second incident surface; and

illumination optical means for having an optically conjugate positional relationship between the second outgoing radiation surface of the second light leading member in the optical device and the predetermined irradiation target surface;

a display device arranged on the irradiation target surface; and

a projection optical system for projecting an image formed by the display device onto a screen,

the light source being an LED which emits light beams from a light emission surface thereof, and

both the first incident surface shape in the first light leading means and a light emission surface shape of the LED being quandrangles.