High efficiency optical devices

• US 6,210,785 B1
• Filed: 12/15/1999
• Issued: 04/03/2001
• Est. Priority Date: 06/26/1995
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Cobb, Sanford Jr., Weber, Michael F., Ouderkirk, Andrew J., Wortman, David L.
• Primary Examiner(s): Chen, Vivian
• Application Number:
  US09/461,245
• Time in Patent Office: 475 Days
• Field of Search: 359/591, 359/592, 359/594, 359/597, 359/598, 359/489, 359/494, 359/485, 359/487, 359/495, 359/500, 428/212, 428/480, 428/910
• US Class Current: 428/212
• 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 such as light pipes which incorporate multilayer optical films in which the refractive indices of two adjacent layers in the thickness direction are substantially matched or are small relative to the difference in refractive indices of said two adjacent layers in an given in-plane direction which is at least 0.05. 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 body having at least two opposing optical surfaces, at least a portion of each of the optical surfaces comprising a reflective film that reflects incident light of at least one polarization orientation over an intended bandwidth,

wherein the reflective film of each of the optical surfaces comprises a plurality of layers,

wherein a refractive index difference between at least two adjacent layers in a first in-plane direction is greater than or equal to a refractive index difference between the at least two adjacent layers in a second in-plane direction for the reflective film,

and further wherein the refractive index difference in the first in-plane direction is greater than a refractive index difference between the at least two adjacent layers in a third out-of-plane direction for the reflective film.

2. The optical device of claim 1, wherein the device comprises a light guide.

3. The optical device of claim 1, wherein the optical surfaces define a volume.

4. The optical device of claim 1, wherein at least one of the optical surfaces comprises a transmissive area.

5. The optical device of claim 4, wherein the transmissive area comprises a void in the optical surface.

6. The optical device of claim 4, wherein the transmissive area transmits light having a first polarization orientation and reflects light having a second polarization orientation.

7. The optical device of claim 1, wherein one of the at least two opposing optical surfaces comprises a mirror and the other optical surface comprises a reflective polarizer.

8. The optical device of claim 1, wherein the reflective film transmits less than 2% of incident light with a first polarization orientation over an intended bandwidth, and wherein the optical device absorbs less than about 10% of the incident light after five reflections from the reflective film of the opposing optical surfaces.

9. The optical device of claim 8, wherein the device comprises a light guide.

10. The optical device of claim 8, wherein at least one of the optical surfaces comprises a transmissive area in which the incident light with the first polarization orientation over the intended bandwidth is transmitted through the surface.

11. An optical device comprising:

a plurality of diverging wedges, each diverging wedge of the plurality of diverging wedges comprising two opposing optical surfaces, wherein each of the optical surfaces comprise a multilayer optical film,

wherein the multilayer optical film comprises a plurality of layers, wherein a refractive index difference between at least two adjacent layers in a first in-plane direction is greater than or equal to a refractive index difference between the at least two adjacent layers in a second in-plane direction, and further wherein the refractive index difference in the first in-plane direction is greater than a refractive index difference between the at least two adjacent layers in a third out-of-plane direction.

12. The optical device of claim 11, wherein the plurality of diverging wedges are connected to each other.

13. The optical device of claim 11, wherein the plurality of diverging wedges comprise a plurality of adjacent diverging wedges.

14. A decorative article comprising:

a plurality of diverging wedges, each diverging wedge of the plurality of diverging wedges comprising two opposing optical surfaces, wherein each of the optical surfaces comprise a multilayer optical film,

wherein the multilayer optical film comprises a plurality of layers, wherein a refractive index difference between at least two adjacent layers in a first in-plane direction is greater than or equal to a refractive index difference between the at least two adjacent layers in a second in-plane direction, and further wherein the refractive index difference in the first in-plane direction is greater than a refractive index difference between the at least two adjacent layers in a third out-of-plane direction.

15. The decorative article of claim 14, wherein the plurality of diverging wedges are connected to each other.

16. The decorative article of claim 14, wherein the plurality of diverging wedges comprise a plurality of adjacent diverging wedges.

17. The decorative article of claim 14, wherein the article comprises a bow.

18. The decorative article of claim 14, wherein the article comprises a flower.