Illumination apparatus, projector, and illumination method

1. A projector comprising:

an illumination optical system;

a light modulation element adapted to modulate a light beam from the illumination optical system; and

a projection optical system adapted to project the light beam modulated by the light modulation element,

wherein the illumination optical system includes a first light source section,

a plurality of second light source sections including one second light source section and another second light source section, and

an optical axis conversion element adapted to emit light beams, which are input from the first light source section and the plurality of second light source sections, in predetermined directions, respectively,

the optical axis conversion element emits the light beam, which is input from the first light source section, so that an exit optical axis of the light beam approximately matches with an illumination optical axis, and emits the light beams, which are respectively input from the plurality of second light source sections, so that exit optical axes of the light beams intersect the exit optical axis of the light beam from the first light source section between the optical axis conversion element and the light modulation element,

the exit optical axis of the light beam of the first light source section is disposed between an exit optical axis of the light beam of the one second light source section and an exit optical axis of the another second light source section,

the optical axis conversion element having a first transmissive end plane disposed at a first end of the optical axis conversion element,

a second transmissive end plane disposed at a second end of the optical axis conversion element opposite the first end, the first and second transmissive end planes being perpendicular to the illumination optical axis, and the first end having a smaller area than the second end, and

an integrator optical system disposed between the optical axis conversion element and the light modulation element.

2. The projector according to claim 1 , wherein

the optical axis conversion element emits the light beams, which are input from the plurality of second light source sections, so that the exit optical axes of all of the light beams from the plurality of second light source sections intersect the exit optical axis of the light beam from the first light source section at a point between the optical axis conversion element and the light modulation element.

3. The projector according to claim 1 , wherein

the integrator optical system includes at least a lens array adapted to divide the light beams, which are input from the first light source section and the plurality of second light source sections, into a plurality of light beams, and

the optical axis conversion element emits the light beams, which are input from the plurality of second light source sections, so that the exit optical axes of all of the light beams from the plurality of second light source sections intersect the exit optical axis of the light beam from the first light source section at a position of or close to the lens array.

4. The projector according to claim 1 wherein

the integrator optical system includes at least an integrator rod, and

the optical axis conversion element emits the light beams, which are input from the plurality of second light source sections, so that the exit optical axes of all of the light beams from the plurality of second light source sections intersect the exit optical axis of the light beam from the first light source section at a position of or close to an incident end of the integrator rod.

5. The projector according to claim 1 , wherein

the first light source section is disposed on an illumination optical axis, and the plurality of second light source sections is disposed at positions shifted from the illumination optical axis.

6. The projector according to claim 5 , wherein

the light beam from the first light source section is focused on a position of or close to an exit end of the optical axis conversion element.

7. The projector according to claim 5 , wherein

the optical axis conversion element reflects the light beams, which are emitted respectively from the plurality of second light source sections, to emit the light beams.

8. The projector according to claim 7 , wherein

on or close to each of constituent reflecting surfaces of the plurality of reflecting surfaces, the light beam from the second light source section corresponding to the reflecting surface is focused.

9. The projector according to claim 7 , wherein

the reflecting surfaces of the optical axis conversion element are surface-reflecting surfaces adapted to surface-reflect the light beams, which are emitted respectively from the plurality of second light source sections.

10. The projector according to claim 9 , wherein

the reflecting surface is provided with a dielectric multilayer film.

11. The projector according to claim 7 , wherein

the reflecting surfaces of the optical axis conversion element are total-reflecting surfaces adapted to totally reflect the light beams, which are emitted respectively from the plurality of second light source sections.

12. The projector according to claim 5 , wherein

the optical axis conversion element refracts the light beams, which are emitted respectively from the plurality of second light source sections, to emit the light beams.

13. The projector according to claim 5 , wherein the one second light source section and the another second light source section are disposed on opposite sides of the illumination optical axis.

14. The projector according to claim 1 , wherein

a first light source section dedicated optical axis conversion element adapted to deflect an optical axis of the light beam, which is emitted from the first light source section, is provided on an entrance side of the optical axis conversion element.

15. The projector according to claim 1 , wherein

a second light source section dedicated optical axis conversion element adapted to deflect an optical axis of the light beam, which is emitted from at least one of the plurality of second light source sections, is provided on an entrance side of the optical axis conversion element.

16. The projector according to claim 1 , wherein

the optical axis conversion element is provided with a radiation member.

17. The projector according to claim 1 , wherein

the optical axis conversion element is housed in a housing having a light transmitting property.

18. The projector according to claim 1 , wherein

the optical axis conversion element has at least two reflecting surfaces tilted at predetermined angles with the illumination optical axis, and each of the light beams, which are emitted from the plurality of second light source sections, is reflected by either one of the plurality of reflecting surfaces,

the at least two reflecting surfaces being formed on opposite sides of the optical axis conversion element and at the same predetermined angle with respect to the illumination optical axis such that the exit optical axes of the light beams reflected by the at least two reflecting surfaces form angles of +α and −α with the illumination optical axis.

19. An illumination apparatus for illuminating an illumination object, comprising:

a first light source section;

a plurality of second light source sections including one second light source section and another second light source section, and

an optical axis conversion element adapted to emit light beams, which are input from the first light source section and the plurality of second light source sections, in predetermined directions, respectively,

wherein the optical axis conversion element emits the light beam, which is input from the first light source section, so that an exit optical axis of the light beam approximately matches with an illumination optical axis, and emits the light beams, which are respectively input from the plurality of second light source sections, so that exit optical axes of the light beams intersect the exit optical axis of the light beam from the first light source section on an exit side and outside of the optical axis conversion element,

the exit optical axis of the light beam of the first light source section is disposed between an exit optical axis of the light beam of the one second light source section and an exit optical axis of the another second light source section,

the optical axis conversion element having a first transmissive end plane disposed at a first end of the optical axis conversion element,

a second transmissive end plane disposed at a second end of the optical axis conversion element opposite the first end, the first and second transmissive end planes being perpendicular to the illumination optical axis, and the first end having a smaller area than the second end, and

an integrator optical system disposed between the optical axis conversion element and the illumination object.

20. An illumination method comprising:

emitting a light beam, which is emitted from a first light source section, towards an illumination object by using an optical axis conversion element so that an exit optical axis of the light beam approximately matches with an illumination optical axis; and

emitting light beams, which are emitted from a plurality of second light source sections including one second light source section and another second light source section, towards the illumination object so that exit optical axes of the light beams intersect the exit optical axis of the light beam from the first light source section on an exit side and outside of the optical axis conversion element,

the exit optical axis of the light beam of the first light source section being disposed between an exit optical axis of the light beam of the one second light source section and an exit optical axis of the another second light source section,

the optical axis conversion element having a first transmissive end plane disposed at a first end of the optical axis conversion element,

a second transmissive end plane being disposed at a second end of the optical axis conversion element opposite the first end, the first and second transmissive end planes being perpendicular to the illumination optical axis, and the first end having a smaller area than the second end, and

an integrator optical system being disposed between the optical axis conversion element and the illumination object.