REFLECTIVE POLARIZER ASSEMBLY

• US 20060244882A1
• Filed: 06/28/2006
• Published: 11/02/2006
• Est. Priority Date: 10/01/2001
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Watson, Philip E., Kotchick, Keith M., Allen, Richard C.
• Granted Patent: US 7,245,431 B2
• Time in Patent Office: Days
• US Class Current: 349/98
• CPC Class Codes: G02B 27/286 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 Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 2203/09 transflective

Abstract

An assembly that includes a first reflective polarizer substantially reflecting light having a first polarization state and substantially transmitting light having a second polarization state, a polarization rotating layer or depolarizing layer (or both) positioned to receive light passing through the first reflective polarizer, and a second reflective polarizer positioned to receive light passing through the polarization rotating layer or depolarizing layer, the second reflective polarizer substantially reflecting light having a third polarization state back through the polarization rotating layer or depolarizing and substantially transmitting light having a fourth polarization state. Articles containing the assembly can be formed.

Claims

1. An assembly, comprising:

a first reflective polarizer substantially reflecting light having a first polarization state and substantially transmitting light having a second polarization state;

a film comprising birefringent material positioned to receive light passing through the first reflective polarizer; and

a second reflective polarizer positioned to receive light passing through the film, the second reflective polarizer substantially reflecting light having a third polarization state back through the film and substantially transmitting light having a fourth polarization state.

2. The assembly of claim 1, wherein a transmission state of the first reflective polarizer is substantially aligned with a transmission state of the second reflective polarizer.

3. The assembly of claim 1, wherein the birefringent material is a liquid crystal material.

4. The assembly of claim 1, wherein the birefringent material is a polymeric material.

5. The assembly of claim 1, wherein the film further comprises an absorbing material.

6. The assembly of claim 1, wherein the film has wavelength dependent properties.

7. The assembly of claim 1, wherein the film is coupled to at least one of the first and the second reflective polarizers.

8. The assembly of claim 1, wherein both the first reflective polarizer and the second reflective polarizer are linear reflective polarizers or circular reflective polarizers.

9. An assembly, comprising:

a first reflective polarizer substantially reflecting light having a first polarization state and substantially transmitting light having a second polarization state;

a compensation film positioned to receive light passing through the first reflective polarizer; and

a second reflective polarizer positioned to receive light passing through the compensation film, the second reflective polarizer substantially reflecting light having a third polarization state back through the compensation film and substantially transmitting light having a fourth polarization state.

10. The assembly of claim 9, further comprising a depolarizing layer disposed between the first and second reflective polarizers, the depolarizing layer converting a portion of incident light into an orthogonal polarization state, wherein the second reflective polarizer is positioned to receive light passing through the compensation film and the depolarizing layer.

11. The assembly of claim 9, wherein a transmission state of the first reflective polarizer is substantially aligned with a transmission state of the second reflective polarizer.

12. The assembly of claim 9, wherein the compensation film is coupled to at least one of the first and the second reflective polarizers.

13. The assembly of claim 9, wherein both the first reflective polarizer and the second reflective polarizer are linear reflective polarizers or circular reflective polarizers.

14. An assembly, comprising:

a first reflective polarizer substantially reflecting light having a first polarization state and substantially transmitting light having a second polarization state;

an absorbing polarizer positioned to receive light passing through the first reflective polarizer; and

a second reflective polarizer positioned to receive light passing through the absorbing polarizer film, the second reflective polarizer substantially reflecting light having a third polarization state back to the absorbing polarizer film and substantially transmitting light having a fourth polarization state.

15. The assembly of claim 14, wherein a transmission state of the first reflective polarizer is substantially aligned with a transmission state of the second reflective polarizer.

16. The assembly of claim 14, wherein the first reflective polarizer is a linear reflective polarizer having a transmission axis, and wherein a transmission axis of the absorbing polarizer is substantially aligned with the transmission axis of the first reflective polarizer.

17. The assembly of claim 14, wherein the absorbing polarizer is coupled to at least one of the first and the second reflective polarizers.

18. The assembly of claim 14, wherein both the first reflective polarizer and the second reflective polarizer are linear reflective polarizers or circular reflective polarizers.