EP0357946B1
Expired / Lapsed
EP
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Method for preparing light polarizer
Assignee: Polaroid Corp
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Filing: 1989-07-29
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Granted: 1994-08-31
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Expires: 2009-07-29
Abstract
No abstract record available.
Inventors
- 👤 Edwin H. Land
- 👤 Anthony J. Dirocco
- 👤 Leonard Polizzotto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:47
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/30; G02B5/3025; G02B5/3033; G02B1/00; G02B1/08; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S428/00; Y10S428/91; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31786; Y10T428/31797; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
241 words
A method of preparing a light polarizer sheet, the method comprising the steps of: providing a support sheet of amorphous polymeric material; uniaxially stretching the amorphous polymeric support sheet in a first direction and at a temperature at or above the glass transition temperature of the polymeric support sheet material to partially orient the molecules of the polymeric support sheet material along said first direction; applying a coating of an aqueous polyvinyl alcohol-containing composition to the surface fo the uniaxially stretched polymeric support sheet; stretching the polyvinyl alcohol-coated uniaxially stretched polymeric support sheet at a temperature at or above the glass transition temperature of the polymeric support sheet material and in a second direction of stretch; said second direction of stretch being at an angle within about ± 60 degrees from a normal to said first direction of stretch; the amount of stretch along said first direction being sufficient to impart to the polymeric support sheet resistance to stress-induced fracture along said first direction, and the amount of stretch along said second direction being sufficient to simultaneously orient the molecules of said polyvinyl alcohol layer to thereby adapt the layer so that it can be modified in such a way that visible dichroism is obtained therein, and to impart to the support layer resistance to stress-induced fracture along said second direction; modifying the polyvinyl alcohol layer in such a way that visible dichroism is obtained therein to provide said light polarizer.
Claim 2
Dependent Claim
64 words
The method of Claim 1 wherein said amorphous polymeric support sheet is stretched along said first direction to about 175 % to about 350 % of its original dimension and wherein said polyvinyl alcohol-coated uniaxially stretched polymeric support sheet is stretched in said second direction to about 300 % to about 700 %, preferably to about 400 to about 600 of its original dimension.
Claim 3
Independent Claim
41 words
The method of Claims 1 and 2, wherein said second direction of stretch is at an angle within about ± 45 degrees, preferably within about ± 10 degrees, in particular 0 degrees, with respect to a normal to said first direction.
Claim 4
Independent Claim
47 words
The method of anyone of Claims 1 to 3, wherein said support sheet of amorphous polymeric material comprises a polyester such as polyethylene terephthalate and each of said first and second stretching steps is conducted at a temperature in the range of 80 °C to 125 °C.
Claim 5
Independent Claim
36 words
The method of anyone Claims 1 to 4, wherein the polyvinyl alcohol containing composition is applied to said uniaxially stretched polymeric support sheet to a dry thickness of from about 0.0064 mm to about 0.0762 mm.
Claim 6
Independent Claim
44 words
The method of anyone of Claims 1 to 5, wherein after said step of uniaxially stretching the amorphous polymeric support sheet, and before said step of applying said coating of polyvinyl alcohol, an adhesive or primer layer is applied to said polymeric support sheet.
Claim 7
Dependent Claim
28 words
The method of Claim 1, wherein said modification of the polyvinyl alcohol layer to obtain visible dichroism is done by staining said layer with an iodine-containing staining composition.
Claim 8
Dependent Claim
36 words
The method of Claim 1, wherein said modification of the polyvinyl alcolhol layer to obtain visible dichroism is done by the contact with hydrochloric acid vapor for conversion of polyvinyl alcohol molecules to polyvinlyene light-polarizing species.
References Cited (Backward Citations)
No citation records indexed.
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