Polarizing beam splitters providing high resolution images and systems utilizing such beam splitters

Patent metadata

Field	Value
Publication number	US-9535256-B2
Application number	US-201214359972-A
Country	US
Kind code	B2
Filing date	Nov 14, 2012
Priority date	Nov 28, 2011
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

Polarizing beam splitters and systems incorporating such beam splitters are described. More specifically, polarizing beam splitters and systems with such beam splitters that incorporate multilayer optical films and reflect imaged light towards a viewer or viewing screen with high effective resolution are described.

First claim

The invention claimed is:

1. A polarization subsystem comprising:
a first imager; and
a polarizing beam splitter receiving imaged light from the imager, the polarizing beam splitter comprising a reflective polarizer;
wherein the reflective polarizer comprises a multilayer optical film, and wherein the polarizing beam splitter reflects imaged light towards a viewer or screen, and
further wherein the imaged light is reflected from the polarizing beam splitter towards a viewer or screen with an effective pixel resolution of less than 12 microns.

2. The polarization subsystem of claim 1 , wherein the imaged light is reflected from the polarizing beam splitter towards a viewer or screen with an effective pixel resolution of less than 9 microns.

3. The polarization subsystem of claim 1 , further comprising a second imager, wherein the polarizing beam splitter receives imaged light from the second imager at a second face and receives imaged light from the first imager at a first face different from the second face.

4. The polarization subsystem of claim 1 , further comprising a projection lens that receives light from the polarizing beam splitter after light is imaged and projects it towards the viewer or screen.

5. The polarization subsystem of claim 1 , wherein the polarizing beam splitter comprises a first cover, a reflective polarizing film, and a second cover, the reflective polarizing film being positioned between the first cover and the second cover.

6. The polarization subsystem of claim 1 , wherein the reflective polarizer has a surface roughness Ra of less than 45 nm or a surface roughness Rq of less than 80 nm.

7. The polarization subsystem of claim 1 , wherein the surface of the multilayer optical film upon which imaged light is reflected is processed to substantially have a flatness of a flat substrate.

8. A three-dimensional image projector comprising the polarization subsystem of claim 1 .

9. A polarizing beam splitter, comprising a reflective polarizer positioned between a first cover and a second cover, the reflective polarizer comprising a multilayer optical film, wherein the polarizing beam splitter is capable of reflecting imaged light towards a viewer or screen, the effective pixel resolution of the imaged light being less than 12 microns after reflection from the polarizing beam splitter.

10. The polarizing beam splitter of claim 9 , wherein the effective pixel resolution of the imaged light is less than 9 microns after reflection from the polarizing beam splitter.

11. The polarizing beam splitter of claim 9 , wherein the first and second cover comprises glass or an optical plastic.

12. The polarizing beam splitter of claim 9 , wherein the first and second cover is attached to the reflective polarizer with a pressure sensitive adhesive, UV cured adhesive or optical epoxy.

13. The polarizing beam splitter of claim 9 , wherein the reflective polarizer is rendered flat via a vacuum process after attaching to the first cover or second cover.

14. The polarizing beam splitter of claim 9 , wherein the reflective polarizer has a surface roughness Ra of less than 45 nm or a surface roughness Rq of less than 80 nm.

15. A projection subsystem, comprising:
a light source;
a polarizing beam splitter receiving light from the light source, the polarizing beam splitter comprising a reflective polarizer, the reflective polarizer comprising a multilayer optical film,
a first imager positioned adjacent to the polarizing beam splitter; and
a second imager positioned adjacent to the polarizing beam splitter on a different side of the polarizing beam splitter than the first imager;
wherein light from the light source is incident upon the polarizing beam splitter, and further wherein a first polarization of incident light is transmitted through the reflective polarizer and a second polarization of incident light orthogonal to the first polarization is reflected by the reflective polarizer; and
wherein light of the second polarization travels from the polarizing beam splitter to the second imager, and is imaged and reflected back towards the polarizing beam splitter; light reflected from the second imager transmitting through the polarizing beam splitter to an image plane; and
wherein light of the first polarization is transmitted through the polarizing beam splitter to the first imager, and is imaged and reflected back towards the polarizing beam splitter; light reflected from the first imager being reflected at the polarizing beam splitter towards an image plane with an effective pixel resolution of less than 12 microns.

16. The projection subsystem of claim 15 , wherein the light reflected from the first imager is reflected at the polarizing beam splitter towards an image plane with an effective pixel resolution of less than 9 microns.

17. The projection subsystem of claim 15 , wherein the reflective polarizer has a surface roughness Ra of less than 45 nm or a surface roughness Rq of less than 80 nm.

18. A polarization subsystem comprising:
a first imager; and
a polarizing beam splitter receiving imaged light from the imager, the polarizing beam splitter comprising a reflective polarizer;
wherein the reflective polarizer comprises a multilayer optical film, and wherein the polarizing beam splitter reflects imaged light towards a viewer or screen, and
wherein the reflective polarizer has a surface roughness Ra of less than 45 nm or a surface roughness Rq of less than 80 nm.

19. The projection subsystem of claim 18 , wherein the reflective polarizer has a surface roughness Ra of less than 40 nm or a surface roughness Rq of less than 70 nm.

20. The projection subsystem of claim 18 , wherein the reflective polarizer has a surface roughness Ra of less than 35 nm or a surface roughness Rq of less than 55 nm.

Assignees

• 3M Innovative Properties Co

Inventors

• Carls Joseph C
• Lee Seong Taek
• Teo Yeow Leng
• Chan Kin Sheng
• Cheng Xiaohui

Classifications

• G02B30/25

  using polarisation techniques · CPC title

• G02B27/286

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title

• G02B27/283 Primary

  used for beam splitting or combining · CPC title

• G02B5/3041

  comprising multiple thin layers, e.g. multilayer stacks · CPC title

• G03B21/14

  Details · CPC title