Front projection screens including reflective and refractive layers of differing spatial frequencies, and methods of fabricating same

• US 20070014004A1
• Filed: 07/12/2005
• Published: 01/18/2007
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Bright View Technologies Corporation (Tredegar Corporation)
• Original Assignee: Bright View Technologies, Inc. (Tredegar Corporation)
• Inventors: Wood, Robert
• Granted Patent: US 7,324,276 B2
• Time in Patent Office: Days
• US Class Current: 359/449
• CPC Class Codes: B29C 39/006 Monomers or prepolymers by reaction injection moulding B29C67/246
• CPC Class Codes: B29C 39/026 characterised by the shape of the surface
• CPC Class Codes: B29D 11/00365 Production of microlenses lenticular sheets B29D11/00278
• CPC Class Codes: B29L 2011/0016 Lenses
• CPC Class Codes: B29L 2011/0083 Reflectors
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 17/008 Systems specially adapted to form image relays or chained systems
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G02B 27/0983 being curved
• CPC Class Codes: G02B 5/0205 characterised by the diffusing properties
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G03B 21/602 Lenticular screens G03B21/625 takes precedence

Abstract

Projection screens include a substrate, a reflective layer on the substrate and a refractive layer on the substrate. The reflective layer includes reflective microstructures of about 5 μm to about 500 μm in size, and arranged in a first pattern to reflect light at a first spatial frequency. The refractive layer includes refractive microstructures of about 5μm to about 500μm in size, and arranged in a second pattern that is different from the first pattern, to refract light at a second spatial frequency that is different than the first spatial frequency. Related fabrication methods also are described.

Claims

1. A projection screen comprising:

a substrate;

a reflective layer on the substrate, the reflective layer comprising reflective microstructures of about 0.5 μ

m to about 500 μ

m in size and arranged in a first pattern to reflect light at a first spatial frequency; and

a refractive layer on the substrate, the refractive layer comprising refractive microstructures of about 0.5 μ

m to about 500 μ

m in size and arranged in a second pattern that is different from the first pattern to refract light at a second spatial frequency that is different than the first spatial frequency.

4. A projection screen according to claim 1 wherein the first pattern comprises a texture pattern and wherein the refractive microstructures comprise an array of anamorphic microlenses.

5. A projection screen according to claim 4 wherein the substrate includes first and second opposing faces, wherein the refractive layer is on the first face and wherein the reflective layer is between the refractive layer and the first face.

6. A projection screen according to claim 4 wherein the substrate includes first and second opposing faces, wherein the refractive layer is on the first face and wherein the reflective layer is on the second face.

12. A projection screen according to claim 1 wherein the reflective microstructures are between about I Jm and about 100pm in size and wherein the refractive microstructures are between about I im and about 1 OOpm in size.

13. A projection screen according to claim 1 wherein the first and second patterns are randomly and/or regularly arranged.

15. A projection screen according to claim 1 wherein the refractive layer is a first refractive layer and wherein the projection screen further comprises a second refractive layer on the substrate, the second refractive layer comprising refractive microstructures of about 0.5 μ

m to about 500 μ

m in size arranged in the first pattern, and wherein the reflective layer extends conformally on the second refractive layer.

16. A projection screen according to claim 15 wherein the substrate includes first and second opposing faces, wherein the first refractive layer is on the first face, wherein the second refractive layer is on the second face and wherein the reflective layer is on the second refractive layer opposite the second face.

2. A projection screen according to claim I wherein the projection screen has a front and a back and wherein the reflective layer and the refractive layer are arranged on the substrate such that light that is projected to the front of the projection screen passes through and is refracted by the refractive layer to impinge on the reflective layer and is reflected from the reflective layer back through the refractive layer to emerge from the front of the projection screen.

3. A projection screen according to claim 2 wherein the projection screen has a vertical axis and a horizontal axis and wherein the reflective layer and/or the refractive layer are configured to produce a vertical half angle of the light that emerges from the front of the projection screen that is less than a horizontal half angle of the light that emerges from the front of the projection screen.

7. A projection screen according to claim 2 wherein the projection screen has a vertical axis and a horizontal axis and wherein the first pattern comprises a plurality of grooves that extend along the vertical axis and wherein the refractive microstructures comprise a plurality of anamorphic microlenses having a vertical half angle that is less than a horizontal half angle thereof.

8. A projection screen according to claim 7 wherein the substrate includes first and second opposing faces, wherein the anamorphic microlenses are on the first face and wherein the plurality of grooves are between the refractive layer and the first face.

9. A projection screen according to claim 2 wherein the projection screen has a vertical axis and a horizontal axis and wherein the first pattern comprises a plurality of anamorphic reflectors having a vertical half angle that is less than a horizontal half angle thereof and wherein the refractive microstructures comprise a plurality of anamorphic microlenses having a vertical half angle that is less than a horizontal half angle thereof.

10. A projection screen according to claim 9 wherein the substrate includes first and second opposing faces, wherein the plurality of anamorphic microlenses are on the first face and wherein the plurality of anamorphic reflectors are on the second face.

11. A projection screen according to claim 2 wherein the projection screen has a vertical axis and a horizontal axis and wherein one of the reflective layer or the refractive layer is configured to preferentially reflect or refract light along the horizontal axis compared to the vertical axis and wherein the other of the reflective layer or the refractive layer is configured to preferentially reflect or refract light along the vertical axis compared to the horizontal axis.

14. (canceled)

17. A projection screen comprising:

a substrate including a reflective metal face having a textured surface to provide reflective microstructures of about 0.5 μ

m to about 500 μ

m in size and arranged in a first pattern to reflect light at a first spatial frequency; and

an array of refractive microstructures of about 0.5 μ

m to about 500 μ

m in size on the textured surface and arranged in a second pattern that is different from the first pattern to refract light at a second spatial frequency that is different than the first spatial frequency.

18. A projection screen according to claim 17 wherein the projection screen has a vertical axis and a horizontal axis and wherein the first pattern comprises a plurality of grooves that extend along the vertical axis and wherein the refractive microstructures comprise a plurality of anamorphic microlenses having a vertical half angle that is less than a horizontal half angle thereof.

19. A projection screen comprising:

a transparent substrate having front and back faces;

a first array of refractive microstructures of about 0.5 μ

m to about 500 μ

m in size on the front face, and arranged in a first pattern to refract light at a first spatial frequency;

a second array of refractive microstructures of about 0.5 μ

m to about 500 μ

m in size on the back face, and arranged in a second pattern that is different from the first pattern to refract light at a second spatial frequency that is different than the first spatial frequency; and

a reflective layer that extends conformally on the second array of microstructures to provide an array of reflective microstructures of about 0.5 μ

m to about 500 μ

m in size on the back face, and arranged in the second pattern to reflect light at the second spatial frequency.

20. A projection screen according to claim 19 wherein the projection screen has a vertical axis and a horizontal axis and wherein the first and second arrays of refractive microstructures comprise respective first and second arrays of anamorphic microlenses having vertical half angles that are less than horizontal half angles thereof.

21. A method of fabricating a projection screen comprising:

texturing a surface of a reflective metal substrate;

arranging a mold of microlenses adjacent the surface that was textured, with liquid photopolymer between the mold and the surface that was textured, to thereby mold the microlenses in the liquid photopolymer;

photocuring the liquid photopolymer; and

removing the mold.

22. A method according to claim 21 wherein arranging a mold of microlenses adjacent the surface that was textured, with liquid photopolymer between the mold and the surface that was textured to thereby mold the microlenses in the liquid photopolymer comprises:

placing the mold adjacent the surface that was textured; and

injecting the liquid photopolymer between the mold and the surface that was textured.

23. A method according to claim 21 wherein arranging a mold of microlenses adjacent the surface that was textured, with liquid photopolymer between the mold and the surface that was textured to thereby mold the microlenses in the liquid photopolymer comprises:

placing the liquid photopolymer on the surface that was textured; and

placing the mold on the liquid photopolymer.