Lightguide having a viscoelastic layer for managing light

• US 9,285,531 B2
• Filed: 07/30/2009
• Issued: 03/15/2016
• Est. Priority Date: 08/08/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Sherman, Audrey A., Meis, Michael A., Boulos, Marie A., Schaffer, Kevin R., Winkler, Wendi J.
• Primary Examiner(s): Sember, Thomas M
• Application Number:
  US13/057,498
• Publication Number:
  US 20110134623A1
• Time in Patent Office: 2,420 Days
• Field of Search: 362/618
• US Class Current: 1/1
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the 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 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0095 Light guides as housings, housing portions, shelves, doors, tiles, windows, or the like

Abstract

Disclosed herein is an optical device including a light source and an optical article. The optical article includes a lightguide and a viscoelastic layer disposed on the lightguide. Light emitted by the light source enters the lightguide and is transported within the lightguide by total internal reflection. The viscoelastic layer manages light, for example, at least about 50%, or less than about 10%, of light that enters the lightguide may be extracted. The optical device can be used in a variety of constructions for signs, markings, display devices, keypad assemblies, tail light assemblies and illumination devices.

Claims

1. An optical device comprising a light source and an optical article, the optical article comprising a lightguide and a viscoelastic cladding layer, wherein the viscoelastic cladding layer comprises a pressure sensitive adhesive, wherein the viscoelastic cladding layer has an index of refraction lower by about 0.2 than an index of refraction of the lightguide and wherein the viscoelastic cladding layer is disposed on the lightguide, and wherein light emitted by the light source enters the lightguide and is reflected at at least a portion of an interface between the lightguide and the viscoelastic cladding layer;

and wherein the interface between the lightguide and the viscoelastic cladding layer comprises a plurality of features oriented to extract light being transported within the lightguide.

2. The optical device of claim 1, wherein the viscoelastic cladding layer comprises first and second regions, wherein at least about 50% of light that enters the lightguide is extracted from the lightguide and into the first region, and less than about 10% of light that enters the lightguide is extracted from the lightguide and into the second region.

3. The optical device of claim 1, wherein the lightguide comprises a polymeric material or glass.

4. The optical device of claim 1, wherein the viscoelastic cladding layer comprises a silicone pressure sensitive adhesive.

5. The optical device of claim 1, wherein the viscoelastic cladding layer comprises a stretch releasable pressure sensitive adhesive.

6. The optical device of claim 1, wherein the viscoelastic cladding layer comprises a (meth)acrylate, rubber, silicone, urethane, or a combination thereof.

7. The optical device of claim 1, wherein the viscoelastic cladding layer comprises first and second regions having different refractive indices.

8. The optical device of claim 1, wherein the optical article has a light transmittance of from about 90 to about 100% and a haze value of from about 0.01 to less than about 5%.

9. The optical device of claim 1, the optical article further comprising a first substrate disposed on the viscoelastic cladding layer opposite the lightguide, wherein the first substrate comprises a polymer, metal, glass, ceramic, release liner, a graphic, paper, fabric, grease, antiseptic gel, or a combination thereof.

10. The optical device of claim 9, wherein the first substrate emits light extracted from the viscoelastic cladding layer.

11. The optical device of claim 10, wherein at least about 50% of light extracted from the viscoelastic cladding layer is emitted from the first substrate.

12. The optical device of claim 10, wherein a surface of the first substrate comprises a plurality of features oriented to emit light from the first substrate.

13. The optical device of claim 10, wherein the first substrate comprises an imaged polymeric film.

14. The optical device of claim 10, wherein light is emitted uniformly from the first substrate.

15. The optical device of claim 10, wherein light is emitted in one or more predetermined directions from the first substrate.

16. The optical device of claim 10, wherein light is emitted at different intensities from the first substrate.

17. The optical device of claim 9, wherein the first substrate does not emit light.

18. The optical device of claim 1, the optical article further comprising a first substrate disposed on the viscoelastic cladding layer opposite the lightguide, wherein the first substrate comprises a multilayer optical film, a reflector, a mirror, a polarizer, a prismatic film, a three-quarter polarizer, a retroreflective film or a combination thereof.

19. The optical device of claim 1, the optical article further comprising a third substrate disposed on the lightguide opposite the viscoelastic cladding layer, wherein the third substrate comprises a multilayer optical film, a reflector, a mirror, a polarizer, a prismatic film, a three-quarter polarizer, a retroreflective film, polymer, metal, glass, ceramic, a graphic, paper, fabric or a combination thereof.

20. The optical device of claim 19, wherein the third substrate emits light extracted from the lightguide.

21. The optical device of claim 19, wherein the third substrate comprises an imaged polymeric film.

22. The optical device of claim 19, wherein light is emitted uniformly from the third substrate.

23. The optical device of claim 19, wherein light is emitted in one or more predetermined directions from the third substrate.

24. The optical device of claim 19, wherein light is emitted at different intensities from the third substrate.

25. A sign or marking comprising the optical device of claim 1.

26. A display device comprising a display panel and the optical device of claim 1.

27. A keypad assembly comprising one or more keys and the optical device of claim 1.

28. A tail light assembly suitable for use with a vehicle, the tail light assembly comprising a housing, a transparent cover and the optical device of claim 1.

29. An illumination device comprising a housing and the optical device of claim 1.