Light source module

• US 8,382,293 B2
• Filed: 04/30/2009
• Issued: 02/26/2013
• Est. Priority Date: 05/05/2008
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Phillips, William E. III, Moskovich, Jacob, Yun, Zhisheng
• Primary Examiner(s): Dowling, William C
• Application Number:
  US12/990,801
• Publication Number:
  US 20110058350A1
• Time in Patent Office: 1,398 Days
• Field of Search: 353/98, 353/99, 353/38, 385/133, 385/901, 362/551, 362/553, 362/555, 362/559, 362/561, 362/227, 362/230, 362/231, 362/234
• US Class Current: 353/102
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: G02B 27/0994 Fibers, light pipes optical fibers per se G02B6/02
• CPC Class Codes: G03B 21/2033 LED or laser light sources
• CPC Class Codes: G03B 21/208 Homogenising, shaping of the illumination light

Abstract

A light source module is disclosed. The light source module includes an emitter having a light emitting surface, a solid integrating optic aligned to accept light emitted from the emitter at an entrance face and deliver light to an exit face, and a lens aligned to receive light from the exit face. The lens has a substantially hemispherical portion having a radius of curvature and the exit face of the solid integrating optic has an exit face diagonal. The ratio of the radius of curvature to the exit face diagonal is greater than 0.7. The solid integrating optic and the lens each have an index of refraction, and the ratio of the lens index of refraction to the solid integrating optic index of refraction is greater than unity.

Claims

1. A light source module, comprising:

an emitter comprising a light emitting surface;

a solid integrating optic aligned to accept light emitted from the emitter at an entrance face and deliver light to an exit face, wherein the exit face has an exit face surface area and an exit face diagonal; and

a lens aligned to receive light from the exit face of the solid integrating optic, the lens comprising a substantially hemispherical portion having a radius of curvature;

wherein

the ratio of the radius of curvature to the exit face diagonal is greater than 0.7; and

the solid integrating optic has a solid integrating optic index of refraction, the lens has a lens index of refraction, and the ratio of the lens index of refraction to the solid integrating optic index of refraction is greater than unity.

2. The light source module of claim 1, wherein the ratio of the lens index of refraction to the solid integrating optic index of refraction is at least 1.3.

3. The light source module of claim 1, wherein the solid integrating optic index of refraction is no greater than 1.7.

4. The light source module of claim 1, wherein the lens index of refraction is at least 1.8.

5. The light source module of claim 1, wherein the lens further comprises a cylindrical portion.

6. The light source module of claim 1, wherein the substantially hemispherical portion of the lens is aspheric.

7. The light source module of claim 1, wherein the light emitting surface comprises an array comprising a plurality of light emitting areas.

8. The light source module of claim 1, wherein the entrance face has dimensions and shape substantially matching dimensions and shape of the light emitting surface.

9. The light source module of claim 1, wherein the exit face has a shape approximately the same as an imager shape.

10. The light source module of claim 1, wherein the entrance face has an entrance face surface area smaller than the exit face surface area.

11. The light source module of claim 1, further comprising an encapsulant disposed between the light emitting surface and the solid integrating optic.

12. The light source module of claim 11, wherein the encapsulant has an encapsulant index of refraction less than the lens index of refraction.

13. The light source module of claim 12, wherein the encapsulant index of refraction is not greater than the solid integrating optic index of refraction.

14. The light source module of claim 1, further comprising a reflective polarizer disposed between the light emitting surface and the entrance face.

15. The light source module of claim 14, wherein the light emitting surface, reflective polarizer, and entrance face are bonded.

16. The light source module of claim 1, further comprising a reflective polarizer disposed between the exit face and the lens.

17. The light source module of claim 16, wherein the exit face, reflective polarizer, and lens are bonded.

18. The light source module of claim 1, wherein the solid integrating optic has at least one side surface having a reflective coating on at least part of the side surface.

19. The light source module of claim 1, further comprising an antireflection coating disposed between the exit face and the lens.

20. A projection system, comprising:

at least one light source module, comprising;

an emitter comprising a light emitting surface;

a solid integrating optic aligned to accept an illumination light emitted from the emitter at an entrance face and deliver the illumination light to an exit face, wherein the exit face has an exit face diagonal; and

a lens aligned to receive the illumination light from the exit face of the solid integrating optic, the lens comprising a substantially hemispherical portion having a radius of curvature, the lens conforming to the exit face over substantially the entire exit face surface area;

wherein

the ratio of the radius of curvature to the exit face diagonal is greater than 0.7; and

the solid integrating optic has a solid integrating optic index of refraction, the lens has a lens index of refraction, and the ratio of the lens index of refraction to the solid integrating optic index of refraction is greater than unity;

an imager;

optical elements arranged to deliver the illumination light from the at least one light source module to the imager; and

a projection lens arranged to receive an image light from the imager and project the image light.