Metal-coated multilayer mirror

• US 6,088,163 A
• Filed: 11/14/1997
• Issued: 07/11/2000
• Est. Priority Date: 06/26/1995
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ouderkirk, Andrew J., Gilbert, Laurence R.
• Primary Examiner(s): HENRY, JON W
• Application Number:
  US08/970,271
• Time in Patent Office: 970 Days
• Field of Search: 359/580, 359/584, 359/585, 359/586, 359/589, 359/359, 359/360, 359/884
• US Class Current: 359/585
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 2307/416 Reflective
• CPC Class Codes: B32B 2307/518 bi-axially
• CPC Class Codes: B32B 2551/08 Mirrors
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/36 comprising polyesters
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G02B 5/0866 incorporating one or more organic, e.g. polymeric layers
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid

Abstract

A metal-coated multilayer mirror having high reflectivity and high specularity. The mirror comprises a multilayered polymer film and a reflective metal layer. The multilayered polymer film preferably comprises layers of a crystalline, semi-crystalline, or liquid crystalline material, such as a naphthalene dicarboxylic acid polyester, having an average thickness of not more than 0.5 microns and layers of a second polymer having an average thickness of not more than 0.5 microns. Preferably, the layers of semi-crystalline naphthalene dicarboxylic acid polyester have a positive stress optical coefficient. The reflective metal layer comprises a metal selected from the group consisting of silver, gold, aluminum, nickel, copper, and titanium, with silver and aluminum being particularly preferred. The metal-coated multilayer mirrors are useful in applications requiring broad bandwidth reflection, high specularity, low manufacturing costs, and high reflectivity.

Claims

1. A metal-coated multilayer mirror comprising a multilayered polymer film reflector in which the layers have an average thickness of not more than 0.5 microns, and at least some of the layers exhibit stress induced birefringence and a metal layer comprising a reflective material.

2. The mirror of claim 1 wherein the reflective metal is selected from the group consisting of aluminum, silver, gold, copper, and titanium.

3. The mirror of claim 1 wherein the reflective metal is silver.

4. The mirror of claim 3 wherein the silver layer has a thickness of at least about 75 nm to about 100 nm.

5. The mirror of claim 1 wherein the reflective metal is aluminum.

6. The mirror of claim 5 wherein the aluminum layer has a thickness of at least about 20 nm to about 30 nm.

7. The mirror of claim 1 wherein the reflective metal is coated on the multilayered polymer film by vapor deposition or cathode sputtering.

8. The mirror of claim 1 wherein the reflective metal comprises a metalized polymer or glass sheet that is laminated to the multilayered polymer film.

9. The mirror of claim 1 wherein the reflective metal comprises a metal sheet laminated to the multilayered polymer film.

10. The mirror of claim 1 wherein its reflectivity of visible light is greater than 95%.

11. A reflective article comprising a polymeric mirror comprising at least one birefringent polymer, said reflective article further comprising a metallic reflector layer.