Display apparatus with corrosion-resistant light directing film

• US 6,264,336 B1
• Filed: 10/22/1999
• Issued: 07/24/2001
• Est. Priority Date: 10/22/1999
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Epstein, Kenneth A., Fleming, Robert J., Lyons, Christopher S., Maki, Stephen P., Gardner, Timothy J., Nachbor, Mark D.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US09/425,765
• Time in Patent Office: 641 Days
• Field of Search: 359/606, 359/607, 359/608, 359/599, 359/850, 359/851, 359/852, 359/497, 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 having two sides, where one side includes 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. In a first embodiment of the invention, the light directing film of the display apparatus further includes an inorganic protective layer formed on the metal layer, wherein the inorganic protective layer inhibits molecular transfer to the metal layer and balances the color of reflected and transmitted light. The light directing film further includes a pressure sensitive adhesive layer between a polarizer and the inorganic protective layer. Alternatively, 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 polymer substrate;

a prismatic structure having two sides, one side 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 protects the metal layer from mobile reactive species in the adhesive 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. A 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. A 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. A 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 wherein the polymer substrate is PET.

14. A display apparatus comprising:

a light modulating layer;

a polarizer;

a light directing film comprising;

a polymer substrate;

a prismatic structure having two sides, one including saw-tooth formations having tilted surfaces;

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

a polymer protective layer of polymethyl methacrylate formed over the silver layer; and

a diffusive adhesive layer formed over the polymer protective layer, adhered 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 protects the silver layer from the adhesive layer.