VISCOELASTIC LIGHTGUIDE

1 . (canceled)

2 . (canceled)

3 . (canceled)

4 . (canceled)

5 . (canceled)

6 . (canceled)

7 . (canceled)

8 . An optical device comprising a light source and an optical article, the optical article comprising a viscoelastic lightguide disposed on a substrate, wherein light emitted by the light source enters the viscoelastic lightguide and is transported within the lightguide by total internal reflection.

9 . The optical device of claim 8 , wherein an interface formed between the viscoelastic lightguide comprises a plurality of features oriented to extract light being transported within the viscoelastic lightguide.

10 . The optical device of claim 8 , wherein at least about 80% of light being transported within the viscoelastic lightguide is extracted from the lightguide and into the substrate.

11 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted from the substrate.

12 . The optical device of claim 8 , wherein at least one surface of the substrate comprises a plurality of features oriented to emit light extracted from the viscoelastic lightguide.

13 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted uniformly from the substrate.

14 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted in one or more predetermined directions from the substrate.

15 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted randomly from the substrate.

16 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted in a predetermined shape from the substrate.

17 . The optical device of claim 8 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted at different intensities from the substrate.

18 . The optical device of claim 8 , wherein greater than about 50% of light is emitted from the substrate, relative to the amount of light that enters the viscoelastic lightguide.

19 . The optical device of claim 8 , wherein:

the viscoelastic lightguide comprises a (meth)acrylic pressure sensitive adhesive, the (meth)acrylic pressure sensitive adhesive comprising

a first monomer comprising a monoethylenically unsaturated alkyl(meth)acrylate monomer, and

a second monomer, wherein a homopolymer of the second monomer has a Tg of at least about 10° C.

20 . The optical device of claim 8 , wherein the substrate comprises a silicone pressure sensitive adhesive.

21 . The optical device of claim 8 , wherein the substrate comprises a stretch releasable pressure sensitive adhesive.

22 . (canceled)

23 . The optical device of claim 8 , wherein the substrate comprises an imaged polymeric film.

24 . The optical device of claim 8 , 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%.

25 . The optical device of claim 8 , wherein the substrate comprises a reflector.

26 . The optical device of claim 8 , wherein the substrate comprises a release liner.

27 . (canceled)

28 . The optical device of claim 8 , wherein the first substrate comprises regions that extract light from the viscoelastic layer, and regions that do not.

29 . An optical device comprising a light source and an optical article, the optical article comprising a viscoelastic lightguide disposed between first and second substrates, wherein light emitted by the light source enters the viscoelastic lightguide and is transported within the lightguide by total internal reflection.

30 . The optical device of claim 29 , comprising a first interface formed between the viscoelastic lightguide and the first substrate and a second interface formed between the viscoelastic lightguide and the second substrate, wherein the first and second interfaces each comprise a plurality of features oriented to extract light being transported within the viscoelastic lightguide.

31 . The optical device of claim 29 , wherein at least about 80% of light being transported within the viscoelastic lightguide is extracted from the lightguide and into the first and second substrates.

32 . The optical device of claim 29 , wherein at least some of the light being transported within the viscoelastic lightguide is emitted from the first and second substrates.

33 . The optical device of claim 29 , wherein greater than about 50% of light is emitted from the first and second substrates, relative to the amount of light that enters the viscoelastic lightguide.

34 . (canceled)

35 . (canceled)

36 . (canceled)

37 . The optical device of claim 29 , wherein the first substrate comprises an imaged polymeric film, and the second substrate comprises a reflector.

38 . (canceled)

39 . The optical device of claim 29 , 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%.

40 . A sign or marking comprising the optical article of claim 1 .

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

42 . A keypad assembly comprising a one or more keys and the optical article of claim 1 .

43 . 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 .

44 . An illumination device comprising a housing, a light emitting layer and the optical device of claim 1 .