OPTICAL FILM WITH CO-CONTINUOUS PHASES

• US 20060114563A1
• Filed: 01/06/2006
• Published: 06/01/2006
• Est. Priority Date: 02/29/1996
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Weber, Michael F., Ouderkirk, Andrew J., Nevitt, Timothy J., Stover, Carl A., Allen, Richard C., Majumdar, Biswaroop, Carlson, Lockwood W., Kotz, Arthur L.
• Granted Patent: US 7,057,816 B1
• Time in Patent Office: Days
• US Class Current: 359/490
• CPC Class Codes: G02B 1/04 made of organic materials, e.g. plastics G02B1/08 takes precedence
• CPC Class Codes: G02B 5/3008 comprising dielectric particles, e.g. birefringent crystals embedded in a matrix
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: Y10T 428/249953 Composite having voids in a component [e.g., porous, cellular, etc.]
• CPC Class Codes: Y10T 428/249955 Void-containing component partially impregnated with adjacent component

Abstract

An optical film is provided which comprises a disperse phase of polymeric particles disposed within a continuous birefringent matrix. The film is oriented, typically by stretching, in one or more directions. The size and shape of the disperse phase particles, the volume fraction of the disperse phase, the film thickness, and the amount of orientation are chosen to attain a desired degree of diffuse reflection and total transmission of electromagnetic radiation of a desired wavelength in the resulting film.

Claims

1. An optical body, comprising:

an open-celled polymeric birefringent first phase; and

a substantially nonbirefringent second phase disposed within the cells of said first phase;

wherein the absolute value of the difference in index of refraction of said first and second phases is Δ

n₁ along a first axis and Δ

n₂ along a second axis orthogonal to said first axis, and wherein the absolute value of the difference between Δ

n₁ and Δ

n₂ is at least about 0.05, and

wherein the diffuse reflectivity of said first and second phases taken together along at least one axis for at least one polarization of electromagnetic radiation is at least about 30%.

2. An optical body, comprising:

an open-celled polymeric birefringent first phase; and

a substantially nonbirefringent second phase disposed within the cells of said first phase;

wherein the absolute value of the difference in index of refraction of said first and second phases is Δ

n₁ along a first axis and Δ

n₂ along a second axis orthogonal to said first axis, and wherein the absolute value of the difference between Δ

n₁ and Δ

n₂ is at least about 0.05, and

wherein said first phase has a larger birefringence than said second phase.

3. The optical body of claim 2, wherein the birefringence of said first phase is at least 0.02 greater than the birefringence of said second phase.

4. The optical body of claim 2, wherein the birefringence of said first phase is at least 0.05 greater than the birefringence of said second phase.