US4806289A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of making a hollow light pipe
Assignee: Dow Chemical Co
•
Filing: 1987-01-16
•
Granted: 1989-02-21
•
Expires: 2007-01-16
Abstract
Abstract A hollow light conductor with enhanced light-transmitting properties is formed by the coextrusion of polymeric materials. The hollow light conductor comprises a continuous annular core layer encased in inner and outer cladding layers.
Inventors
- 👤 Larry J. Laursen
- 👤 Virgil W. Coomer
- 👤 Walter J. Schrenk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:06
CPC Classifications
B; B29; B29D; B29D11/00; G; G02; G02B; G02B6/00; G02B6/02; G02B6/032; B29C; B29C48/00; B29C48/03; B29C48/05; B29C48/09; B29C48/16; B29C48/18; B29C48/21; B29C48/25; B29C48/30; B29C48/32; B29C48/335; B29C48/336; B29C48/3363; B29C48/36; B29C48/49; B29D11/00663; B29C55/00; B29K; B29K2995/00; B29K2995/0037; B29K2995/005; B29L; B29L2011/00; B29L2011/0075
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
114 words
A method of constructing a hollow light conductor, comprising the steps of: heat plasticizing a core material which is capable of conducting light; heat plasticizing a cladding material which has an index of refraction that is lower than the index of refraction of said core material; coextruding said cladding material along the inner and outer surfaces of said core material to form a tri-layer hollow light conductor having smooth surfaces between said core material and said cladding material with said core material being formed in a predetermined shape; and cooling said light conductor below the glass transition temperatures of said cladding and core materials so that said light conductor will maintain said predetermined shape.
Claim 2
Independent Claim
114 words
A method of constructing a hollow light conductor, comprising the steps of: heat plasticizing a core material which is capable of conducting light; heat plasticizing a cladding material which has an index of refraction that is lower than the index of refraction of said core material; coextruding said cladding material along the inner and outer surfaces of said core material to form a tri-layer hollow light conductor having smooth surfaces between said core material and said cladding material with said core material being formed in a predetermined shape; and cooling said light conductor below the glass transition temperatures of said cladding and core materials so that said light conductor will maintain said predetermined shape.
Claim 3
Dependent Claim
13 words
The method according to claim 1, wherein said predetermined shape is substantially annular.
Claim 4
Dependent Claim
18 words
The method according to claim 1, wherein said core material is polystyrene and said cladding material is PMMA.
Claim 5
Dependent Claim
26 words
The method according to claim 1, including the step of introducing a gas flow through the center of said hollow light conductor during said coextrusion step.
Claim 6
Dependent Claim
20 words
The method according to claim 1, wherein said light conductor is drawn around rolls which are operating at different speeds.
Claim 7
Dependent Claim
30 words
The method according to claim 1, wherein said light conductor is drawn at a temperature above the glass transition temperatures of said core and cladding materials to provide molecular orientation.
Claim 8
Dependent Claim
18 words
The method according to claim 1, wherein said core material is PMMA and said cladding material is PVDF.
Claim 9
Dependent Claim
12 words
The method according to claim 1, wherein said core material is SAMS.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-21 | 1992-08-22 | 1993-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-21 | 1996-08-22 | 1997-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-21 | 2000-08-22 | 2001-02-21 | $7700.00 | Window Closed / Lapsed |