Light directing construction having corrosion resistant feature

• US 6,626,545 B2
• Filed: 12/31/2002
• Issued: 09/30/2003
• 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., Griffith, Richard F.
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US10/335,334
• Publication Number:
  US 20030095332A1
• Time in Patent Office: 273 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: G02B 1/105 Protective coatings
• CPC Class Codes: G02B 1/111 using layers comprising organic materials
• CPC Class Codes: G02B 1/14 Protective coatings, e.g. hard coatings
• CPC Class Codes: G02B 5/045 Prism arrays
• 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 light directing construction for use in a display apparatus. The light directing construction includes a light directing film that has a prismatic structure having two sides, where one side includes saw tooth formations having tilted surfaces, and a metal coating on the side of the prismatic substrate having the saw-tooth formations. A corrosion-resistant feature is provided on the light directing construction to minimize the effects of corrosion experienced in salt atmospheres. In a first embodiment of the invention, the light directing construction includes an intermediate layer positioned between the light directing film and the metal coating. In a second embodiment of the invention, a peripheral polymeric coating is provided on the light directing constriction. This peripheral coating can be formed with a laser.

Claims

1. A light directing construction, comprising:

(a) a prismatic structure having first and second surfaces, the second surface including saw-tooth formations having tilted surfaces;

the prismatic structure made from a non-halogenated UV polymerizable composition;

(b) a transflective metal coating provided proximate to the saw-tooth formations, the transflective metal coating having a transmission of at least 10% of visible light; and

(c) a corrosion resistant intermediate layer present between the transflective metal coating and the prismatic structure, the corrosion resistant layer providing a decrease in the sum of transmission and reflection of visible light of less than 5%.

2. The light directing construction of claim 1 wherein the corrosion resistant layer provides a decrease in the sum of transmission and reflection of visible light of less than 2%.

3. The light directing construction of claim 1 wherein the UV polymerizable composition comprises a cross-linked epoxy acrylate.

4. The light directing construction of claim 3 wherein the UV polymerizable composition comprises bisphenol-A epoxy diacrylate, at a weight percent of about 55-80% of the total UV-curable resin material;

methyl styrene, at a weight percent of about 5-25% of the total UV-curable resin material;

acrylated epoxy, at a weight percent of about 1-10% of the total UV-curable resin material;

a photoinitiator, at a weight percent of about 0.25-5% of the total UV-curable resin material; and

a fluorosurfactant, at a weight percent of about 0.1-0.3% of the total UV-curable resin material.

5. The light directing construction of claim 1 wherein the transflective metal coating comprises a material selected from a group consisting of silver, chromium, nickel, aluminum, titanium, gold, zirconium, platinum, palladium, rhodium, and alloys thereof.

6. The light directing construction of claim 5 wherein the transflective metal coating comprises silver.

7. The light directing construction of claim 5 wherein the tranflective metal coating has a thickness of about 300 angstroms to about 400 angstroms.

8. The light directing construction of claim 1 wherein the corrosion resistant layer comprises a material selected from the group consisting of chromium, nickel, iron, aluminum, titanium, silver, gold, haffiium, zirconium, tantalum, niobium, tungsten, platinum, vanadium, molybdenum, tin, palladium, rhodium, and alloys thereof.

9. The light directing construction of claim 8 wherein the corrosion resistant layer comprises a nickel-chromium alloy.

10. The light directing construction of claim 9 wherein the corrosion resistant layer comprises a nickel-chromium-iron alloy.

11. The light directing construction of claim 1 further comprising:

(a) a pressure sensitive adhesive layer formed on the inorganic protective layer; and

(b) a polarizer disposed on the pressure sensitive adhesive layer.

12. The light directing construction of claim 11, 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 coating.

13. The light directing construction of claim 12, wherein the pressure sensitive adhesive layer includes optical diffuser particles.

14. The light directing construction of claim 1 further comprising:

(a) a polymer protective layer;

(b) a pressure sensitive adhesive layer formed on the polymer protective layer; and

(c) a polarizer disposed on the pressure sensitive adhesive layer.

15. The light directing construction of claim 14, 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.

16. The light directing construction of claim 14 wherein the polymer protective layer has a thickness of about 1 nanometer to 25 micrometers.

17. The light directing construction of claim 14, 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.

18. The light directing construction of claim 14, wherein the polymer protective layer includes polymethyl methacrylate.

19. The light directing construction of claim 1, further comprising a polymer substrate disposed on the first surface, the polymer substrate comprising a material selected from the group of PET, polyether sulphone, polycarbonate, cellulose diacetate, and cellulose triacetate.

20. The light directing construction of claim 19, the polymer substrate having a thickness of greater than or equal to about 25 micrometers and less than or equal to about 1000 micrometers.

21. The light directing construction of claim 1, wherein the prismatic layer includes tilted surfaces with a tilt angle of about 6°

to about 9°

.

22. The light directing construction of claim 1, wherein the saw-tooth formations have a repeat distance of about 30 micrometers to about 80 micrometers.