High efficiency optical devices

• US 7,833,593 B2
• Filed: 01/31/2007
• Issued: 11/16/2010
• Est. Priority Date: 06/26/1995
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wortman, David L., Cobb, Sanford Jr., Weber, Michael F., Ouderkirk, Andrew J.
• Primary Examiner(s): Chen; Vivian
• Application Number:
  US11/669,624
• Publication Number:
  US 20070122641A1
• Time in Patent Office: 1,385 Days
• Field of Search: None
• US Class Current: 428/34.1
• CPC Class Codes: B32B 2250/05 5 or more layers
• CPC Class Codes: B32B 2250/42 Alternating layers, e.g. ABAB(C), AABBAABB(C)
• CPC Class Codes: B32B 2307/42 Polarizing, birefringent, filtering
• CPC Class Codes: B32B 2307/518 bi-axially
• CPC Class Codes: B32B 2307/704 Crystalline
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 2551/00 Optical elements
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/30 comprising vinyl (co)polymers; comprising acrylic (co)polymers
• CPC Class Codes: B32B 27/302 comprising aromatic vinyl (co)polymers, e.g. styrenic (co)polymers
• CPC Class Codes: B32B 27/304 comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: B32B 7/023 Optical properties
• CPC Class Codes: G02B 5/0841 comprising organic materials, e.g. polymers
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 : for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0096 : the lights guides being of the hollow type
• CPC Class Codes: G02F 1/133545 : Dielectric stack polarisers
• CPC Class Codes: G02F 1/133615 : Edge-illuminating devices, i.e. illuminating from the side
• CPC Class Codes: G02F 1/13362 : providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: Y10S 428/91 : Product with molecular orientation
• CPC Class Codes: Y10T 428/13 : Hollow or container type article [e.g., tube, vase, etc.]
• CPC Class Codes: Y10T 428/1352 : Polymer or resin containing [i.e., natural or synthetic]
• CPC Class Codes: Y10T 428/139 : Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 : Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/24322 : Composite web or sheet
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/24967 : Absolute thicknesses specified
• CPC Class Codes: Y10T 428/31504 : Composite [nonstructural laminate]
• CPC Class Codes: Y10T 428/31786 : Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31797 : Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31935 : Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31938 : Polymer of monoethylenically unsaturated hydrocarbon

Abstract

Optical devices according to the present invention include a multilayer optical film in which at least one of the layers comprises an oriented birefringent polymer. The multilayer optical film exhibits low absorptivity and can reflect light approaching at shallow angles as well as normal to the film.

Claims

1. An optical device comprising:

a substantially enclosed volume separating at least two opposing reflective surfaces, a first of the two opposing reflective surfaces comprising an asymmetric reflective film that preferentially transmits light polarized along a first axis of the film over light polarized along a second axis of the film orthogonal to the first axis;

wherein the asymmetric reflective film has a reflectivity for visible light polarized parallel to the first axis that increases at off-normal angles of incidence.

2. The optical device of claim 1, wherein the asymmetric reflective film comprises a polymeric multilayer film.

3. The optical device of claim 1, wherein a second of the two opposing reflective surfaces comprises a multilayer mirror film.

4. The optical device of claim 3, wherein the multilayer mirror film has a reflectance of at least 95%.

5. The optical device of claim 3, wherein the multilayer mirror film has a reflectance of at least 99%.

6. The optical device of claim 1, wherein a second of the two opposing reflective surfaces is selectively transmissive.

7. The optical device of claim 1, wherein the substantially enclosed volume comprises a hollow volume.

8. The optical device of claim 1, wherein the asymmetric reflective film transmits an average of less than 50% of visible light polarized along the first axis and transmits an average of less than 20% of visible light polarized along the second axis.

9. The optical device of claim 1, wherein the asymmetric reflective film has an RMS color that is less than 10% for visible light incident at angles of at least 30 degrees from the normal.

10. The optical device of claim 1, wherein the asymmetric reflective film is laminated to a support.

11. The optical device of claim 1, further comprising a mechanism for randomizing polarization orientation of light reflected back into the enclosed volume.

12. The optical device of claim 1 disposed to allow transmission of polarized light into a liquid crystal display panel.