REAR PROJECTION SCREENS AND LIGHT FILTERS WITH CONFORMABLE COATINGS AND METHODS OF MAKING THE SAME

• US 20020051290A1
• Filed: 06/09/1999
• Published: 05/02/2002
• Est. Priority Date: 06/09/1998
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation
• Original Assignee: Avery Dennison Corporation
• Inventors: HANNINGTON, MICHAEL
• Granted Patent: US 6,600,599 B2
• Time in Patent Office: Days
• US Class Current: 359/452
• CPC Class Codes: G03B 21/60 characterised by the nature of the surface
• CPC Class Codes: Y10T 156/109 Embedding of laminae within face of additional laminae
• CPC Class Codes: Y10T 428/24372 Particulate matter
• CPC Class Codes: Y10T 428/24876 Intermediate layer contains particulate material [e.g., pigment, etc.]
• CPC Class Codes: Y10T 428/24926 including ceramic, glass, porcelain or quartz layer
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]

Abstract

AVER 2363 This invention relates to a light transmitting filter comprising (a) light absorbing layer having a first and second surface, (b) microspheres embedded in the light absorbing layer and (c) an optically clear, substantially uniform, conformable layer covering the microspheres, wherein the microspheres provide light tunnels through the light absorbing layer. The invention also relates to methods of making the same. The invention also relates to a method of preparing a light transmitting filter comprising the step of laminating a clear substantially uniform conformable layer over transparent microspheres embedded in a light absorbing layer wherein the transparent bead form light tunnels through the light absorbing layer. The light transmitting filters of the present invention have improved light throughput and improved angularity.

Claims

1. A light transmitting filter comprising (a) light absorbing layer having a first and second surface, (b) microspheres embedded in the light absorbing layer and (c) an optically clear, substantially uniform, conformable layer covering the first surface of the light absorbing layer, wherein the microspheres provide light tunnels through the light absorbing layer.

2. The filter of claim 1 wherein the light absorbing layer comprises polymethacrylate and at least one pigment.

3. The filter of claim 1 wherein the light absorbing layer comprises a black polyvinylcarboxylate.

4. The filter of claim 1 wherein the microspheres have a diameter from about 25 to about 300 microns.

5. The filter of claim 1 wherein the conformable layer has an average thickness from about 2.5 microns to about 270 microns.

6. The filter of claim 1 wherein the conformable layer comprises a polymethacrylate or polyvinylcarboxylate.

7. The filter of claim 1 wherein the second surface of the light absorbing layer is adhered to an optically clear support layer.

8. The filter of claim 7 wherein the clear support layer comprises a polyester or polymethacrylate.

9. The filter of claim 1 further comprising a polymeric tie layer between the clear conformable layer and the first surface of the light absorbing layer.

10. A light transmitting filter comprising (a) light absorbing layer having a first and second surface, (b) a monolayer of transparent microspheres embedded in the light absorbing layer, wherein the microspheres provide light tunnels through the light absorbing layer, and (c) an optically clear, highly conformable layer laminated in substantially full contact with the microsphere covered surface of the light absorbing layer, whereby it is in contact with, and follows the curved surfaces of, the microspheres protruding from the light absorbing layer, and has a thickness of about 10% to about 90% of the diameter of the average microsphere.

11. The light transmitting filter of claim 10 in which the light absorbing layer has a thickness from about 10% to 80% of the microsphere diameter.

12. The light transmitting filter of claim 10 in which the transparent microspheres which provide light tunnels through the light absorbing layer are embedded to a level of about 10% to about 80% of their diameter.

13. The light transmitting filter of claim 10 in which the transparent microspheres which provide light tunnels through the light absorbing layer are present in substantially a monolayer generally covering from 60% to about 90% of the surface area of the assembly.

14. The light transmitting filter of claim 10 in which the transparent microspheres which provide light tunnels through the light absorbing layer are have a refractive index from about 1.5 to about 2.3.

15. The light transmitting filter of claim 10 in which the transparent microspheres have an average diameter from about 25 to about 300 microns and vary in diameter through a range less than 50% of the average diameter of the microspheres.

16. The light transmitting filter of claim 10 wherein the conformable layer comprises a polymethacrylate or polyvinylcarboxylate.

17. The light transmitting filter of claim 10 further comprising a polymeric tie layer between the clear conformable layer and the first surface of the light absorbing layer.

19. The method of claim 18 wherein the microspheres are embedded in the light absorbing layer by placing the microspheres on a substrate and partially surrounding the microspheres with a light absorbing material.

20. The method of claim 18 in which the Vicat softening point of the molding layer is less than that of the optically clear conformable layer.

21. The method of claim 18 in which in which the light absorbing layer has a thickness from about 10% to 80% of the microsphere diameter.

22. The method of claim 18 in which the transparent microspheres which provide light tunnels through the light absorbing layer are present in substantially a monolayer generally covering from 60% to about 90% of the surface area of the assembly.

23. The method of claim 18 in which the transparent microspheres which provide light tunnels through the light absorbing layer are have a refractive index from about 1.5 to about 2.3.

24. The method of claim 18 in which the transparent microspheres have an average diameter from about 25 to about 300 microns and vary in diameter through a range less than 50% of the average diameter of the microspheres.

25. The method of claim 18 wherein the conformable layer comprises a polymethacrylate or polyvinylcarboxylate.

26. The method of claim 18 further comprising a polymeric tie layer between the clear conformable layer and the first surface of the light absorbing layer.

27. The method of claim 18 further comprising a silicone release layer between the clear conformable layer and the molding layer.

29. The method of claim 28 wherein the molding layer is a polyolefin and the support layer is a paper or polymeric liner.

30. The method of claim 28 wherein the light absorbing layer comprises polymethacrylate or polyvinylcarboxylate and at least one pigment, and the support layer is paper or a polymeric liner.

31. The method of claim 28 wherein transparent microspheres are embedded in the light absorbing layer.

32. The method of claim 28 wherein the transparent microspheres are embedded in the optically clear polymeric layer.

33. The method of claim 28 further comprising a polymeric tie layer on the optically clear polymeric layer.

34. The method of claim 33, wherein the transparent microspheres are embedded in the tie layer.

18. The method of making a light transmitting filter comprising the steps of (1) providing (a) a first assembly comprising a light absorbing layer having a first and second surface, and a monolayer of transparent microspheres embedded in the light absorbing layer, wherein the microspheres provide light tunnels through the light absorbing layer;

and (b) a second assembly comprising an optically clear, highly conformable layer, a molding layer, and a substrate;

(2) laminating the microsphere containing surface of the first assembly to the optically clear highly conformable surface of the second assembly; and

(3) removing the substrate and molding layer, where the conformable layer remains on the microspheres, follows the curved surfaces of the microspheres, and is substantially uniform.

28. A method of preparing a light transmitting filter comprising the steps of

(1) providing a first construction comprising a molding layer having a first and second surface, a support layer on the first surface of the molding layer, and an optically clear polymeric layer on the second surface of the molding layer, wherein the Vicat softening point of the optically clear polymeric layer is greater than the Vicat softening point of the molding layer,

(2) providing a second construction comprising a light absorbing layer with a first and second surface, and a support layer on the first surface of the light absorbing layer,

(3) heat laminating the optically clear polymeric layer of the first construction to the second surface of the second construction,

(4) removing the support layer and molding layer from the laminate, provided that either the first or second construction contains transparent microspheres and the transparent microspheres form light tunnels through the light absorbing layer.