COMPACT OPTICAL INTEGRATOR

• US 20130010360A1
• Filed: 01/03/2011
• Published: 01/10/2013
• Est. Priority Date: 01/06/2010
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ouderkirk, Andrew J., Yun, Zhisheng, Tan, Kim L.
• Application Number:
  US13/520,190
• Publication Number:
  US 20130010360A1
• Time in Patent Office: Days
• US Class Current: 359/485.07
• CPC Class Codes: G02B 2207/117 Adjustment of the optical path length
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0977 Reflective elements
• CPC Class Codes: G02B 27/283 used for beam splitting or combining

Abstract

Generally, the present disclosure describes a compact optical integrator that provides an increased path length for a beam of light in a compact projection system. The increased path length can improve the uniformity of the light passing through the compact projection system, with a minimal increase in the size of the system. The light can be homogenized by mixing light entering the integrator from different regions of the input area. The compact optical integrator can be positioned in the optical path between a light source and a spatial light modulator, such as a liquid crystal display (LCD) or a digital micro-mirror (DMM) array.

Claims

1. An optical integrator, comprising:

a polarizing beam splitter (PBS) having an input surface disposed to receive an input light beam normal to the input surface, an output surface, and a first and a second side surface;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees; and

a first polarization rotating reflector disposed facing the first side surface,

wherein the reflective polarizer and the polarization rotating reflector cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about two times a length of the PBS measured normal to the input surface.

2. The optical integrator of claim 1, wherein the input surface and the output surface are on adjacent surfaces of the PBS.

3. The optical integrator of claim 1, further comprising a second polarization rotating reflector disposed facing the second side surface.

4. The optical integrator of claim 3, wherein the input surface and the output surface are on opposing surfaces of the PBS, and the reflective polarizer and the polarization rotating reflectors cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about three times a length of the PBS measured normal to the input surface.

5. The optical integrator of claim 3, wherein the input surface and the output surface are on adjacent surfaces of the PBS, and the reflective polarizer and the polarization rotating reflectors cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about three times a length of the PBS measured normal to the input surface.

6. An optical integrator, comprising:

a polarizing beam splitter (PBS) having an first surface disposed to receive an input light beam normal to the first surface, a first side surface, a second side surface, and a third side surface;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees; and

a first, a second, and a third polarization rotating reflector disposed facing the second, third and fourth side surfaces, respectively,

wherein the reflective polarizer and the polarization rotating reflectors cooperate so that a path length of the input light beam from the first surface, through the optical integrator, and returning to the first surface is at least about four times a length of the PBS measured normal to the first surface.

7. An optical integrator, comprising:

a first polarizing beam splitter (PBS), including;

a first input surface disposed to receive an input light beam normal to the input surface, a first output surface adjacent the first input surface, a second output surface opposite the first input surface, and a first side surface;

a first reflective polarizer aligned to a first polarization direction and disposed within the first PBS to intercept the input light beam at an angle of approximately 45 degrees;

a first polarization rotating reflector disposed facing the first side surface;

a second PBS, including;

a second input surface disposed facing the first output surface and capable of receiving a first output light beam from the first PBS, and three side surfaces;

a second reflective polarizer aligned to the first polarization direction and disposed within the second PBS to intercept the first output light beam at an angle of approximately 45 degrees; and

a second, a third, and a fourth polarization rotating reflector disposed facing each of the three side surfaces,

wherein the reflective polarizers and the polarization rotating reflectors cooperate so that a path length of the input light beam from the first input surface to the second output surface within the optical integrator is at least about seven times a length of the first PBS measured normal to the input surface.

8. An optical integrator, comprising:

a first and a second polarizing beam splitter (PBS), each PBS comprising;

an input surface disposed to receive an input light beam normal to the input surface, an output surface adjacent the input surface, and two side surfaces;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees;

a first and a second polarization rotating reflector disposed facing each of the two side surfaces;

wherein the output surface of the first PBS faces the input surface of the second PBS, and further

wherein the reflective polarizers and the polarization rotating reflectors cooperate so that a path length of the input light beam from the input surface of the first PBS to the output surface of the second PBS within the optical integrator is at least about six times a length of the first PBS measured normal to the input surface.

9. An optical integrator, comprising:

a polarizing beam splitter (PBS) having an input surface disposed to receive an input light beam normal to the input surface, an output surface adjacent the input surface, and two side surfaces;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees;

a retarder disposed immediately adjacent the reflective polarizer and opposite the input surface, the retarder aligned at an angle of approximately 45 degrees to the first polarization direction; and

a first and a second broadband mirror disposed facing each of the two side surfaces;

wherein the reflective polarizer, the retarder, and the broadband mirrors cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about three times a length of the PBS measured normal to the input surface.

10. An optical integrator, comprising:

a polarizing beam splitter (PBS) having a first surface disposed to receive an input light beam normal to the first surface, a second surface adjacent the first surface, and two side surfaces;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees;

a retarder disposed immediately adjacent the reflective polarizer and opposite the input surface, the retarder aligned at an angle of approximately 45 degrees to the first polarization direction;

a first and a second broadband mirror disposed facing each of the two side surfaces; and

a polarization rotating reflector disposed facing the second surface,

wherein the reflective polarizer, the retarder, the polarization rotating reflector, and the broadband mirrors cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about three times a length of the PBS measured normal to the input surface.

11. An optical integrator, comprising:

a first polarizing beam splitter (PBS), including;

a first input surface disposed to receive an input light beam normal to the input surface, a first output surface adjacent the first input surface, a second output surface opposite the first input surface, and a first side surface;

a first reflective polarizer aligned to a first polarization direction and disposed within the first PBS to intercept the input light beam at an angle of approximately 45 degrees;

a first polarization rotating reflector disposed facing the first side surface;

a second PBS, including;

a second input surface disposed facing the first output surface and capable of receiving a first output light beam from the first PBS, a first, a second, and a third side surfaces;

a second reflective polarizer aligned to the first polarization direction and disposed within the second PBS to intercept the first output light beam at an angle of approximately 45 degrees;

a retarder disposed immediately adjacent the second reflective polarizer, opposite the second input surface;

a first and a second broadband mirror disposed facing the first and the second side surfaces, respectively, adjacent the retarder; and

a second polarization rotating reflector disposed facing the third side surface,

wherein the reflective polarizers, the polarization rotating reflectors, the retarder, and the broadband mirrors cooperate so that a path length of the input light beam from the first input surface to the second output surface within the optical integrator is at least about seven times a length of the first PBS measured normal to the input surface.

12. An optical integrator, comprising:

a first and a second polarizing beam splitter (PBS), each PBS comprising;

an input surface disposed to receive an input light beam normal to the input surface, an output surface adjacent the input surface, and two side surfaces;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees;

a retarder disposed immediately adjacent the reflective polarizer and opposite the input surface, the retarder aligned at an angle of approximately 45 degrees to the first polarization direction; and

a first and a second broadband mirror disposed facing each of the two side surfaces;

wherein the output surface of the first PBS is facing the input surface of the second PBS, and further

wherein the reflective polarizers, the retarders, and the broadband mirrors cooperate so that a path length of the input light beam from the input surface to the output surface within the optical integrator is at least about six times a length of the PBS measured normal to the input surface.

13. An optical integrator, comprising:

a first and a second polarizing beam splitter (PBS), each PBS comprising;

an input surface disposed to receive an input light beam normal to the input surface, a first output surface, a second output surface opposite the input surface, and a side surface;

a reflective polarizer aligned to a first polarization direction and disposed within the PBS to intercept the input light beam at an angle of approximately 45 degrees;

a first polarization rotating reflector disposed facing the side surface, wherein the first output surface of the first PBS faces the first output surface of the second PBS; and

a half-wave retarder disposed between the first output surface of the first PBS and the first output surface of the second PBS,

wherein the reflective polarizers, the polarization rotating reflectors, and the half-wave retarder cooperate so that a path length of the input light beam from the input surface of the first PBS to the second output surface of the second PBS within the optical integrator is at least about three times a length of the first PBS measured normal to the input surface.

14-20. -20. (canceled)