Display apparatus with corrosion-resistant light directing film

• US 6,508,560 B2
• Filed: 12/20/2001
• Issued: 01/21/2003
• Est. Priority Date: 10/22/1999
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Gardner, Timothy J., Epstein, Kenneth A.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US10/028,345
• Publication Number:
  US 20020067547A1
• Time in Patent Office: 397 Days
• Field of Search: 359/606, 359/607, 359/601, 359/608, 359/599, 359/850, 359/851, 359/852, 359/497, 359/493, 349/57, 349/62, 349/64, 349/86, 349/112, 349/113, 362/31
• US Class Current: 359/606
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133553 Reflecting elements associated to illuminating devices G02F1/133605
• CPC Class Codes: G02F 2202/022 polymeric

Abstract

The present invention is a display apparatus that provides protection against damage for a metallic layer. The display apparatus includes a light modulating layer, a polarizer, and a light directing film. The light directing film includes a prismatic structure including saw tooth formations having tilted surfaces and a metal layer on the side of the prismatic substrate having the saw-tooth formations. A tilt angle of the tilted surfaces offsets an optimal viewing angle for the display from a glare angle for the display. The light directing film of the display apparatus of the present invention includes a polymer protective layer formed over the metal layer to protect the metal layer from damage. The light directing film also includes a diffuse adhesive layer formed over the polymer layer, attached to the polarizer. The polymer protective layer protects the metal layer from the adhesive layer. The display apparatus may include both the inorganic protective layer and the polymer protective layer, in one embodiment.

Claims

1. A display apparatus comprising:

a light modulating layer;

a polarizer; and

a light directing film, comprising;

a substrate having a prismatic structure including saw-tooth formations having tilted surfaces;

a metal layer on the side of the prismatic substrate having saw-tooth formations;

a polymer protective layer formed over the metal layer; and

a diffuse adhesive layer formed over the polymer layer, attached to the polarizer;

wherein the display apparatus has a glare angle at which front surface glare is viewed and a tilt angle of the tilted surfaces of the saw-tooth formations offsets an optimal viewing angle for the display from the glare angle;

wherein the polymer protective layer is configured to protect the metal layer from mobile reactive species in the adhesive layer by inhibiting molecular transfer to the metal layer.

2. The display apparatus of claim 1 wherein the metal layer comprises a silver layer having a thickness of about 400 angstroms.

3. The display apparatus of claim 1 wherein the polymer protective layer is selected from a group consisting of soluble polyester, epoxy resin, acrylic resin, epoxy acrylate, polyethylene, polyvinylidene chloride, and polyvinyl alcohol.

4. The display apparatus of claim 1 wherein the polymer protective layer comprises polymethyl methacrylate.

5. The display apparatus of claim 4 wherein the polymer protective layer has a thickness of about 10 microns.

6. The display apparatus of claim 1 wherein the polymer protective layer comprises one side adjacent to the saw tooth formations and a second side that is substantially planar.

7. The display apparatus of claim 1 wherein the diffuse adhesive layer comprises butyl acrylate acrylic acid.

8. The display apparatus of claim 1 wherein the prismatic structure comprises UV curable epoxy acrylate.

9. The display apparatus of claim 1 wherein the saw-tooth formations include tilted surfaces at about 6 degrees or more and about 9 degrees or less.

10. The display apparatus of claim 1, wherein the saw-tooth formations have a repeat distance of about 5 microns or more and about 200 microns or less.

11. The display apparatus of claim 1, wherein the saw-tooth formations have a repeat distance of about 30 microns or more and about 80 microns or less.

12. The display apparatus of claim 1, wherein the saw-tooth formations have a repeat distance of about 50 microns.

13. The display apparatus of claim 1, the polymer protective layer comprising an additive that inhibits corrosion in metals.

14. The display apparatus of claim 13 wherein the additive is glycol dimercaptoacetate.

15. The display apparatus of claim 1 wherein the polymer protective layer is conformally deposited onto the metal layer.

16. The display apparatus of claim 1 wherein the polymer protective layer is configured to protect the metal layer from airborne pollutants, solid borne ions, reactive monomers and solvents.