EP0488544A1
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Birefringent interference polarizer
Assignee: 3M Co
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Filing: 1991-11-08
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Granted: —
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Expires: 2011-11-08
Abstract
Abstract A birefringent interference polarizer which may be fabricated from readily available materials using established coextrusion techniques is provided. The polarizer has a level of light absorption near zero and can be fabricated to polarize and reflect light of specific wavelengths while transmitting light of other wavelengths. The polarizer includes multiple alternating oriented layers of at least first and second polymeric materials having respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between the polymeric materials. The refractive index mismatch in a first plane of polarization is different from the refractive index mismatch in a second plane normal to the first plane. The refractive index mismatch in the first plane is preferably at least 0.03.
Inventors
- 👤 Walter J. Schrenk
- 👤 John A. Wheatley
- 👤 Victor S. Chang
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 22:28
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; G; G02; G02B; G02B5/00; G02B5/30; B32B27/18; B32B27/20; B32B27/36; B32B33/00; B32B7/00; B32B7/02; B32B7/023; G02B1/00; G02B1/04; G02B1/08; G02B5/08; G02B5/0816; G02B5/0825; G02B5/0841; G02B5/0883; G02B5/20; G02B5/26; G02B5/3025; G02B5/3033; G02B5/3041; G02B5/305; B32B2307/00; B32B2307/40; B32B2307/418; B32B2307/50; B32B2307/514; B32B2307/516; B32B2367/00; B32B2369/00; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1335; G02F1/133528; G02F1/133545; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
72 words
A birefringent interference polarizer comprising multiple alternating oriented layers of at least first and second polymeric materials wherein the said materials have respective nonzero stress optical coefficients which are sufficiently different to produce a refractive index mismatch between said first and second polymeric materials in a first plane which is different from the refractive index mismatch between said first and second polymeric materials in a second plane normal to said first plane.
Claim 2
Dependent Claim
22 words
A polarizer as claimed in Claim 1 in which said first and second polymeric materials have substantially equal refractive indices when unoriented.
Claim 3
Dependent Claim
29 words
A polarizer as claimed in Claim 1 or Claim 2 in which said oriented first and second polymeric materials have substantially equal refractive indices in one of said planes.
Claim 4
Dependent Claim
22 words
A polarizer as claimed in any one of the preceding claims in which said first and second polymeric materials are uniaxially oriented.
Claim 5
Dependent Claim
34 words
A polarizer as claimed in any one of the preceding claims in which said first polymeric material has a positive stress optical coefficient and said second polymeric material has a negative stress optical coefficient.
Claim 6
Dependent Claim
25 words
A polarizer as claimed in any one of the preceding claims in which said refractive index mismatch in said first plane is at least 0.03.
Claim 7
Dependent Claim
26 words
A polarizer as claimed in any one of the preceding claims in which the optical thickness of each layer is from 0.09 micrometers to 0.70 micrometers.
Claim 8
Dependent Claim
25 words
A polarizer as claimed in any one of the preceding claims in which said layers increase in thickness monotonically to produce a layer thickness gradient.
Claim 9
Dependent Claim
24 words
A polarizer as claimed in any one of the preceding claims in which said first polymeric material is a polycarbonate or a polyethylene terephthalate.
Claim 10
Dependent Claim
34 words
A polarizer as claimed in any one of the preceding claims in which said second poymeric material is polystyrene, a copolymer of styrene and acrylonitrile, a copolymer of styrene and methylmethacrylate, or polyethylene naphthalate.
Claim 11
Dependent Claim
21 words
A polarizer as claimed in any one of the preceding claims in which said second polymeric material is a syndiotactic polystyrene.
Claim 12
Dependent Claim
35 words
A polarizer as claimed in any one of the preceding claims in which said polarizer reflects and polarizes a portion of the light incident on its surface while transmitting the remainder of said incident light.
Claim 13
Dependent Claim
38 words
A polarizer as claimed in any one of the preceding claims in which said polarizer reflects and polarizes substantially all light incident in said first plane while transmitting and polarizing substantially all light incident in said second plane.
Claim 14
Dependent Claim
43 words
A polarizer as claimed in any one of the preceding claims in which said first and second polymeric materials comprise copolymers or miscible blends of polymers to adjust the respective refractive indices, stress optical coefficients, and glass transition temperatures of said polymeric materials.
Claim 15
Dependent Claim
27 words
A polarizer as claimed in any one of the preceding claims in which a coloring agent is incorporated into at least one layer of said birefringent polarizer.
Claim 16
Dependent Claim
18 words
A polarizer as claimed in Claim 15, in which said coloring agent is a pigment or a dye.
Claim 17
Dependent Claim
33 words
A polarizer as claimed in any one of the preceding claims in which said polarizer is tunable by variably polarizing wavelengths of light dependent upon the degree of elongation of said polymeric materials.
Claim 18
Dependent Claim
17 words
A polarizer as claimed in any one of the preceding claims wherein the polymeric materials are elastomers.
Claim 19
Independent Claim
73 words
A method of making a birefringent interference polarizer comprising the steps of: coextruding at least first and second polymeric materials having respective nonzero stress optical coefficients in multiple alternating layers, and stretching said layers to orient said polymeric materials and produce a refractive index mismatch in a first plane which is different from the refractive index mismatch between said first and second polymeric materials in a second plane normal to said first plane.
Claim 20
Dependent Claim
30 words
The method of Claim 19 in which said stretching step is carried out at a temperature above the glass transition temperature but below the melting temperature of said polymeric materials.
Claim 21
Dependent Claim
23 words
The method of Claim 19 or Claim 20 in which said first and second polymeric materials have substantially equal refractive indices when unoriented.
Claim 22
Independent Claim
27 words
The method of any one of Claims 19 to 21 wherein the stretching is carried out so as to orient said first and second polymeric materials uniaxially.
Claim 23
Independent Claim
33 words
The method of any one of Claims 19 to 22 in which said first polymeric material has a positive stress optical coefficient and said second polymeric material has a negative stress optical coefficient.
Claim 24
Independent Claim
25 words
The method of any one of Claims 19 to 23 in which the refractive index mismatch in the plane of orientation is at least 0.03.
Claim 25
Independent Claim
26 words
The method of any one of Claims 19 to 24 in which the final optical thickness of each layer is from 0.09 micrometers to 0.70 micrometers.
Claim 26
Independent Claim
24 words
The method of any one of Claims 19 to 25 in which said layers increase in thickness monotonically to produce a layer thickness gradient.
Claim 27
Independent Claim
21 words
The method of any one of Claims 19 to 26 in which said first polymeric material is polycarbonate or polyethylene terephthalate.
Claim 28
Independent Claim
35 words
The method of any one of Claims 19 to 27 in which the said second polymeric material is polystyrene, a copolymer of styrene and acrylonitrile, a copolymer of styrene and methyl methacrylate, or polyethylene naphthalate.
Claim 29
Dependent Claim
15 words
The method of Claim 28 in which said second polymeric material is a syndiotactic polystyrene.
References Cited (Backward Citations)
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