Illuminating device and projector

1. An illuminating device, comprising:

a light source,

an optical unit configured to adjust direction of light from the light source,

a reflector,

a light pipe, and

an exciter,

wherein the light pipe receives light having a first wavelength from the optical unit and direct the light having the first wavelength onto the exciter, the exciter converts the light having the first wavelength into light having the second wavelength and reflects the light having the second wavelength to the reflector, wherein a circumferential wall of the light pipe is configured to reflect the light having the first wavelength and to transmit the light having the second wavelength.

2. The illuminating device according to claim 1 ,

wherein the light pipe is tapered.

3. The illuminating device according to claim 2 ,

wherein an inner side of the circumferential wall of the light pipe is coated with a dichromic coating.

4. The illuminating device according to claim 2 ,

wherein the circumferential wall of the light pipe is a dichromic mirror.

5. The illuminating device according to claim 1 ,

wherein the reflector is an ellipse reflector.

6. The illuminating device according to claim 1 ,

wherein the reflector is a reflector with an opening, and the opening is configured in such a manner that the light pipe is at least partially inserted into the reflector through the opening.

7. The illuminating device according to claim 6 ,

wherein the light pipe comprises a first end and a second end, wherein the second end has a size smaller than that of the first end, and the light pipe is at least partially inserted into the ellipse reflector by the second end.

8. The illuminating device according to claim 1 ,

wherein an optical axis of the light pipe passes through a focus of the reflector.

9. The illuminating device according to claim 7 ,

wherein the light pipe receives, at the first end, the light having the first wavelength from the optical unit, and directs at the second end, the light having the first wavelength onto the exciter.

10. The illuminating device according to claim 5 ,

wherein the exciter is provided at first focus of the ellipse reflector.

11. The illuminating device according to claim 6 ,

wherein a distance between the exciter and the second end of the light pipe is 0.5 mm-1.0 mm.

12. The illuminating device according to claim 6 ,

wherein the optical unit comprises collimating lenses, compression optics and a focus lens located in sequence on light path.

13. The illuminating device according to claim 5 ,

wherein the ellipse reflector is a hollow ellipse reflector.

14. The illuminating device according to claim 13 ,

wherein a reflective layer is coated on an end surface of the second end of the light pipe.

15. The illuminating device according to claim 5 , wherein the ellipse reflector comprises a first portion and a second portion, wherein the first portion and the second portion are assembled with each other to define a cavity for inserting the light pipe.

16. The illuminating device according to claim 15 , wherein inner surfaces and outer surfaces of the first portion and the second portion are configured to reflect the light having the second wavelength and to transmit the light having the first wavelength.

17. The illuminating device according to claim 2 , wherein the light pipe is a quadrangular truncated cone, and the light pipe comprises four wall portions assembled together, and the wall portions jointly form the circumferential wall of the light pipe.

18. The illuminating device according to claim 2 ,

wherein the light pipe is a circular truncated cone, and the light pipe comprises two semicylindrical wall portions assembled together, and the wall portions jointly form the circumferential wall of the light pipe.

19. The illuminating device according to claim 5 ,

wherein the exciter comprises a plurality of areas having different excitation properties from each other.

20. The illuminating device according to claim 19 ,

wherein the exciter is a phosphor.