Patent US4357286A successfully refreshed from Google Patents.
US4357286A
Expired / Lapsed
US
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Method of making a graphite-glass composite laser mirror
Assignee: RTX Corp
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Filing: 1980-11-05
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Granted: 1982-11-02
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Expires: 2000-11-05
Abstract
Abstract A laser mirror stable at high and low temperatures is described comprising graphite fibers in a glass matrix. The mirror is made by hot pressing a graphite fiber lay-up in a glass matrix in a die having a highly polished mirror replicating surface, the fibers laid up in such a way to produce a central plane of symmetry across the central plane of the composite. In use, the composite requires a separate laser reflecting surface layer. The resulting laser mirror has a low density but no porosity, high elastic stiffness, high strength, high fracture toughness, low thermal expansion, high thermal conductivity and environmental stability.
Inventors
- 👤 Robert K. Stalcup
- 👤 Karl M. Prewo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:47
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
72 words
A method of making a laser mirror comprising laying up alternating ply stacks of graphite fibers and particulate glass in a pressing mold having a highly polished mirror replicating surface, said laying being glass-rich against the replicating surface, hot pressing the graphite-glass in the mold to form a laser mirror composite having a mirror surface requiring little or no surface polishing, and applying a laser radiation reflecting layer to the mirror surface.
Claim 2
Independent Claim
72 words
A method of making a laser mirror comprising laying up alternating ply stacks of graphite fibers and particulate glass in a pressing mold having a highly polished mirror replicating surface, said laying being glass-rich against the replicating surface, hot pressing the graphite-glass in the mold to form a laser mirror composite having a mirror surface requiring little or no surface polishing, and applying a laser radiation reflecting layer to the mirror surface.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the replicating surface is a flat surface.
Claim 4
Dependent Claim
13 words
The method of claim 1 wherein the replicating surface is a curved surface.
Claim 5
Dependent Claim
34 words
The process of claim 1 wherein the mirror contains 40% to 70% by volume graphite fibers having an orientation in the composite of 0° and 90°; 0°, 45° and 90° or 0° and 60°.
Claim 6
Dependent Claim
10 words
The process of claim 1 wherein the glass comprises borosilicate.
Claim 7
Dependent Claim
36 words
The process of claim 1 wherein the graphite fibers have a modulus of elasticity of at least 531 GPa, a tensile strength of at least 1724 MPa and a density of about 1.96 gm/cm 3 .
References Cited (Backward Citations)
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Cited
US3131238A
Cited
US3311522A
Cited
US3766000A
Cited
US3645608A
Cited
FR2215631A1
Cited
US4268562A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-01 | 1986-05-03 | 1986-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-01 | 1990-05-03 | 1990-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-01 | 1994-05-03 | 1994-11-02 | $7700.00 | Window Closed / Lapsed |