Transmissive optical polarizing filters designed to maximize a desired portion of a spectral output

• US 6,310,673 B1
• Filed: 07/30/1999
• Issued: 10/30/2001
• Est. Priority Date: 05/23/1995
• Status: Expired due to Term

• Current Assignee: RealD Incorporated
• Original Assignee: University Technology Corporation
• Inventors: Sharp, Gary D.
• Primary Examiner(s): Parker, Kenneth
• Application Number:
  US09/362,954
• Time in Patent Office: 823 Days
• Field of Search: 349/106, 349/18, 349/117, 349/119, 349/61, 359/634, 359/113
• US Class Current: 349/106
• CPC Class Codes: G02B 27/288 Filters employing polarising elements, e.g. Lyot or Solc filters G02B5/3016 takes precedence
• CPC Class Codes: G02F 1/0136 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation G02F1/0353 takes precedence
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 1/13473 for wavelength filtering or for colour display without the use of colour mosaic filters
• CPC Class Codes: G02F 1/23 for the control of the colour G02F1/03 - G02F1/21 take precedence
• CPC Class Codes: G02F 2413/04 Number of plates greater than or equal to 4
• CPC Class Codes: G02F 2413/08 with a particular optical axis orientation
• CPC Class Codes: H04N 5/66 Transforming electric information into light information scanning details H04N3/00
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells
• CPC Class Codes: H04N 9/3111 for displaying the colours sequentially, e.g. by using sequentially activated light sources sequential projection in colour photography G03B33/08
• CPC Class Codes: H04N 9/3126 for spatial light modulators in series
• CPC Class Codes: H04N 9/3167 for polarizing the light beam polarizing optical systems per se G02B27/28

Abstract

This invention provides a complementary color polarizer using a single polarizing film followed by a stack of two or more retarders. In a preferred embodiment, the color polarizers of this invention produce orthogonally polarized complementary primary colors (red/cyan, green/magenta, or blue/yellow). This invention further provides color filters which utilize the color polarizers of this invention in combination with a polarization separator to separate the orthogonally polarized colors. The polarization separator can be passive, such as a polarizing beam splitter, or active, such as a switchable polarizer. The switchable polarizer can employ a nematic or a smectic liquid crystal cell. Two color filters of this invention can be cascaded to provide a three color (RGB) filter with an off-state. In combination with a monochrome display or camera, the color filters of this invention provide color displays or cameras.

Claims

1. A transmissive color polarization manipulator, comprising:

a retarder stack comprising at least three retarder films each having a retardance and an orientation selected such that, when light from an optical source passes through the at least three retarder films, a desired spectral portion of the optical source is substantially polarized with a first polarization and a different spectral portion is substantially polarized with an orthogonal polarization, wherein the retardance and orientation of each of the at least three retarder films is selected such that the optical power for the desired spectral portion of the optical source substantially polarized with a first polarization is substantially maximized for the given number of retarder films.

2. The device of claim 1, wherein the at least three retarder films comprise polymer retarders.

3. The device of claim 1, wherein the at least three retarder films comprise thin films.

4. The device of claim 1, wherein the desired spectral portion comprises a desired color.

5. The device of claim 4, wherein the desired color comprises a desired primary color.

6. The device of claim 4, wherein the desired color is saturated.

7. An optical system, comprising:

an optical source that outputs light having a given spectral output and a given power distribution within the spectral output; and

a transmissive color polarization manipulator comprising at least two retarder films optically coupled to the optical source, wherein each of the at least two retarder films has a retardance and an orientation selected such that, when light from the optical source passes through the at least two retarder films, a desired spectral portion of the optical source is substantially polarized with a first polarization and a different spectral portion is substantially polarized with an orthogonal polarization, wherein the retardance and orientation of each of the at least two retarder films is selected such that the optical power for the desired spectral portion of the optical source substantially polarized with a first polarization is substantially maximized for the given number of retarder films.

8. The device of claim 7, wherein the at least two retarder films comprise polymer retarders.

9. The device of claim 7, wherein the at least two retarder films comprise thin films.

10. The device of claim 7, wherein the desired spectral portion comprises a desired color.

11. The device of claim 10, wherein the desired color comprises a desired primary color.

12. The device of claim 10, wherein the desired color is saturated.

13. A transmissive color polarization manipulator, comprising at least five retarder films arranged in a stacked configuration and each having a retardance and an orientation selected such that, when light from an optical source passes through the at least five retarder films, a desired spectral portion of the optical source is substantially polarized with a first polarization and a different spectral portion is substantially polarized with an orthogonal polarization, wherein the retardance and orientation of each of the at least five retarder films is selected such that the optical power for the desired spectral portion of the optical source substantially polarized with a first polarization is substantially maximized for the given number of retarder films.

14. The color polarization manipulator of claim 13, wherein the at least five retarder films comprise one or more polymer films.

15. The color polarization manipulator of claim 13, wherein the at least five retarder films are stacked on top of each other.

16. The color polarization manipulator of claim 13, wherein the at least five retarder films comprise at least fifteen retarder films.

17. The color polarization manipulator of claim 13, wherein at least two or more of the at least five retarder films abut each other.

18. The color polarization manipulator of claim 13, wherein the at least five retarder films abut each other.

19. An optical system, comprising:

an optical source; and

a transmissive color polarization manipulator comprising a plurality of optical retarders optically coupled to each other and to the optical source, each of the plurality of retarders having an orientation and a retardance selected such that, when light from the optical source passes through the plurality of retarders, a desired spectral portion having at least one predetermined color coordinate is substantially polarized with a first polarization and a different spectral portion is substantially polarized with an orthogonal polarization, wherein the retardances and orientations of each of the retarders are selected such that a throughput of the desired spectral portion substantially polarized with a first polarization is substantially maximized for the given number of retarders.

20. The optical system of claim 19, wherein the at least one predetermined color coordinate comprises a predetermined hue.

21. The optical system of claim 20, wherein the predetermined hue corresponds to a primary color.

22. The optical system of claim 19, wherein the at least one predetermined color coordinate comprises a predetermined saturation.

23. The optical system of claim 19, wherein the at least one predetermined color coordinate comprises a predetermined saturation and a predetermined hue.

24. The optical system of claim 19, wherein the desired spectral portion substantially polarized with the first polarization has a substantially saturated hue.

25. The optical system of claim 24, wherein the substantially saturated hue is a substantially saturated primary color.

26. A transmissive color polarization manipulator for receiving light from an optical source and outputting a desired spectral portion having at least one predetermined color characteristic, comprising:

a plurality of retarders optically coupled to each other and to an optical source, each of said plurality of retarders having an orientation and a retardance selected such that, when light from the optical source passes through the plurality of retarders, the desired spectral portion having at least one predetermined color characteristic is substantially polarized with a first polarization and a different spectral portion is substantially polarized with an orthogonal polarization, wherein the retardances and orientations of the retarders are selected such that a throughput of the desired spectral portion substantially polarized with a first polarization is substantially maximized for the given number of retarders.

27. The color polarization manipulator of claim 26, wherein the at least one predetermined color characteristic comprises a predetermined hue.

28. The color polarization manipulator of claim 27, wherein the predetermined hue corresponds to a prixmary color.

29. The color polarization manipulator of claim 26, wherein the at least one predetermined color characteristic comprises a predetermined saturation.

30. The color polarization manipulator of claim 26, wherein the at least one predetermined color characteristic comprises a predetermined saturation and a predetermined hue.

31. The color polarization manipulator of claim 26, wherein the desired spectral portion has a substantially saturated hue.

32. The color polarization manipulator of claim 31, wherein the substantially saturated hue is a substantially saturated primary color.