Display apparatus with corrosion-resistant light directing film

• US 6,357,880 B2
• Filed: 04/12/2001
• Issued: 03/19/2002
• 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: Maki, Stephen P., Gardner, Timothy J, Epstein, Kenneth A., Fleming, Robert J., Lyons, Christopher S., Nachbor, Mark D.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US09/834,164
• Publication Number:
  US 20010019452A1
• Time in Patent Office: 341 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 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 the saw-tooth formations;

an inorganic protective layer formed on the metal layer, wherein the inorganic protective layer inhibits molecular transfer to the metal layer; and

a pressure sensitive adhesive layer between the polarizer and the inorganic protective layer;

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

wherein the inorganic protective layer protects the metal layer and balances the color of reflected and transmitted light.

2. The display apparatus of claim 1, wherein the pressure sensitive adhesive layer comprises an acrylate acrylic acid adhesive layer, the adhesive layer being optically diffuse, and wherein the adhesive layer inhibits damage to the metal layer.

3. The display apparatus of claim 1, wherein the pressure sensitive adhesive layer includes optical diffuser particles.

4. The display apparatus of claim 1, wherein the inorganic protective layer is selected from the group consisting of titanium and titanium oxides.

5. The display apparatus of claim 4 wherein the inorganic protective layer has a thickness greater than or equal to about 10 angstroms and less than or equal to about 3000 angstroms.

6. The display apparatus of claim 1, wherein the inorganic protective layer is selected from the group consisting of indium tin oxide, zinc sulfide, tin oxide, indium oxide, and titanium oxide.

7. The display apparatus of claim 6 wherein the inorganic protective layer has a thickness greater than or equal to about 300 angstroms and less than or equal to about 1000 angstroms.

8. The display apparatus of claim 1, wherein the inorganic protective layer is selected from the group consisting of silicon dioxide, silicon monoxide, and magnesium fluoride.

9. The display apparatus of claim 8 wherein the inorganic protective layer has a thickness greater than or equal to about 300 angstroms and less than or equal to about 1500 angstroms.

10. The display apparatus of claim 1, the light directing film further comprising a polymer protective layer, formed on the inorganic protective layer, the pressure sensitive adhesive layer being between the polymer protective layer and the polarizer, wherein the polymer protective layer impedes molecular transfer to the metal layer.

11. The display apparatus of claim 10, wherein the polymer protective layer is selected from a group consisting of polyester, soluble polyester, cross-linked epoxy resin, acrylic resin, epoxy acrylate, polyethylene, polyvinylidene chloride, polyvinyl alcohol and polymethyl methacrylate.

12. The display apparatus of claim 11 wherein the polymer protective layer is formed by vapor deposited and cured polymer precursor materials.

13. The display apparatus of claim 12 wherein the polymer protective layer is formed by condensing a vaporized liquid composition containing a monomer or pre-polymer onto the metal layer.

14. The display apparatus of claim 12 wherein the polymer protective layer is cured using a process selected from the group of thermal radiation, ultraviolet radiation, electron beam radiation, plasma exposure and corona exposure.

15. The display apparatus of claim 14 wherein the polymer protective layer has a thickness of about 1 nanometer to 2 micrometers.

16. The display apparatus of claim 10 wherein the polymer protective layer is formed by a plasma process selected from the group consisting of plasma-polymerization and plasma-enhanced chemical vapor deposition.

17. The display apparatus of claim 10, wherein the polymer protective layer has a thickness of about 100 to 5000 Angstroms.

18. The display apparatus of claim 10, wherein the polymer protective layer includes one side having tilted surfaces corresponding to the tilted surfaces of the prismatic structure and a second side being substantially planar.

19. The display apparatus of claim 10, wherein the polymer protective layer includes polymethyl methacrylate.

20. The display apparatus of claim 10, wherein the polymer protective layer is solution coated.

21. The display apparatus of claim 1 further comprising a polymer substrate.

22. The display apparatus of claim 21, the polymer substrate comprising a material selected from the group of PET, polyether sulphone, polycarbonate, cellulose diacetate, and cellulose triacetate.

23. The display apparatus of claim 21, the polymer substrate being birefringent.

24. The display apparatus of claim 21, the polymer substrate being non-birefringent.

25. The display apparatus of claim 21, the polymer substrate having a thickness of greater than or equal to about 25 microns and less than or equal to about 1000 microns.

26. The display apparatus of claim 1, the prismatic structure comprising cured resin.

27. The display apparatus of claim 1, the prismatic structure comprising UV curable cross-linked epoxy-acrylate.

28. The display apparatus of claim 1, the metal layer comprising a material selected from a group consisting of silver, chromium, nickel, aluminum, titanium, aluminum-titanium alloy, gold, zirconium, platinum, palladium, aluminum-chromium alloy and rhodium.

29. The display apparatus of claim 1, the metal layer having a thickness greater than or equal to about 25 angstroms and less than or equal to about 3000 angstroms.

30. The display apparatus of claim 1, wherein the metal layer is vacuum deposited.

31. The display apparatus of claim 1, wherein the metal layer is deposited by plating.

32. The display apparatus of claim 1, further comprising a light cavity for providing light to the light modulating layer, adjacent to the prismatic polymer substrate, wherein the metal layer is partially transmissive.

33. The display apparatus of claim 1, wherein the pressure sensitive adhesive layer includes one side having tilted surfaces corresponding to the tilted surfaces of the prismatic structure and a second side being substantially planar.

34. The display apparatus of claim 1, further comprising a cured polymer layer between the metal layer and the pressure sensitive adhesive layer, the cured polymer layer including one side having tilted surfaces corresponding to the tilted surfaces of the prismatic structure and a second side being substantially planar.

35. The display apparatus of claim 1, wherein the pressure sensitive adhesive layer is incorporated into the polarizer.

36. The display apparatus of claim 1, wherein the pressure sensitive adhesive layer is incorporated into the prismatic polymer substrate.

37. A display apparatus of claim 1, wherein the prismatic layer includes tilted surfaces with a tilt angle of about 1°

or more and about 35°

or less from horizontal.

38. A display apparatus of claim 1, wherein the prismatic layer includes tilted surfaces with a tilt angle of about 3°

or more and about 12°

or less from horizontal.

39. A display apparatus of claim 1, wherein the prismatic layer includes tilted surfaces with a tilt angle of about 6°

or more and about 9°

or less from horizontal.

40. 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.

41. 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.

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