Curved retarder-based optical filters

• US 9,457,523 B2
• Filed: 03/17/2014
• Issued: 10/04/2016
• Est. Priority Date: 10/11/2007
• Status: Expired due to Fees

• Current Assignee: RealD Incorporated
• Original Assignee: RealD Incorporated
• Inventors: Coleman, David A., Sharp, Gary D.
• Primary Examiner(s): Musser, Barbara J
• Application Number:
  US14/216,561
• Publication Number:
  US 20140373997A1
• Time in Patent Office: 932 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B29D 11/00634 Production of filters
• CPC Class Codes: B29D 11/00644 polarizing
• CPC Class Codes: B29D 11/0073 Optical laminates
• CPC Class Codes: B29K 2995/0034 Polarising
• CPC Class Codes: B32B 2307/40 having particular optical properties light or UV resistant B32B2307/71
• CPC Class Codes: B32B 37/12 characterised by using adhesives
• CPC Class Codes: B32B 38/1866 conforming the layers or laminate to a convex or concave profile
• CPC Class Codes: G02B 30/25 using polarisation techniques
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 156/1007 Running or continuous length work
• CPC Class Codes: Y10T 156/1744 Means bringing discrete articles into assembled relationship

Abstract

Curved polarization filters and methods of manufacturing such filters are described in the present disclosure. An exemplary method includes laminating a planar polarization layer to a planar retarder layer at a predetermined orientation and bending the laminate to create a curved filter. The strain on the retarder layer results in stress-induced birefringence, and the predetermined orientation of the retarder substantially compensates for the stress-induced birefringence. In some embodiments, the predetermination is based on mathematical models. In some other embodiment, the predetermination is based on experimental data.

Claims

1. A method for manufacturing a curved optical filter, the method comprising:

providing a drum having a curved surface;

feeding a first optical film onto the drum at a first rate;

feeding a second optical film onto an outer surface of the first optical film at a second rate;

coating the outer surface of the first optical film or an inner surface of the second optical film with an adhesive;

rotating the drum as the first and second optical films are being fed; and

laminating the first and second optical films together using a press roller, whereby the laminated first and second optical films have a curvature.

2. The method of claim 1, wherein the first optical film is fed onto the curved surface of the drum.

3. The method of claim 1, wherein the first and second optical films are fed into the drum at different angles with respect to a tangent of the curved surface of the drum.

4. The method of claim 1, wherein the drum and an inner surface of the curved filter have the same curvature.

5. The method of claim 1, wherein the first optical film is a polarizer.

6. The method of claim 1, wherein the first optical film is a retarder.

7. The method of claim 5, wherein the second optical film is a retarder.

8. The method of claim 1, wherein the adhesive is a pressure-sensitive adhesive.

9. The method of claim 1, wherein the second rate is faster than the first rate.