Patent US4252440A successfully refreshed from Google Patents.
US4252440A
Expired / Lapsed
US
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Photomechanical transducer
Assignee: National Aeronautics and Space Administration
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Filing: 1978-12-15
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Granted: 1981-02-24
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Expires: 1998-12-15
Abstract
Abstract Light absorbing ultra-thin films mounted under a fixed strain exhibit the behavior of an optomechanicalor photomechanical transducer. The transducer responds to light in a quick and reversible manner converting a time-variable light source into a time-variable mechanical stress easily monitored by a device such as a strain gage.
Inventors
- 👤 with respect to an invention of Frosch Robert A. Administrator of the National Aeronautics and Space Administration
- 👤 Robert F. Fedors
- 👤 Mohammad N. Sarbolouki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:44
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/56
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
139 words
A photomechanical transducer comprising in combination: an ultrathin strip of a metal or a polymer film having a high glass transition temperature and first and second ends and said strip having a thickness below 75 μm, a low creep rate, a high elastic modulus, high thermal expansion coefficient, low heat capacity and a very highly efficient light absorptive surface; means mounting said surface of the strip in the path of a light illumination source including a first fixed clamping means and a second moveable clamping means for clamping said first and second ends; means for applying a small constant strain to the strip attached to the second moveable clamping means; and strain measuring means connected to the moveable clamping means for measuring dimensional changes in said strip in response to light absorption of said surface from the illumination source.
Claim 2
Dependent Claim
139 words
A photomechanical transducer comprising in combination: an ultrathin strip of a metal or a polymer film having a high glass transition temperature and first and second ends and said strip having a thickness below 75 μm, a low creep rate, a high elastic modulus, high thermal expansion coefficient, low heat capacity and a very highly efficient light absorptive surface; means mounting said surface of the strip in the path of a light illumination source including a first fixed clamping means and a second moveable clamping means for clamping said first and second ends; means for applying a small constant strain to the strip attached to the second moveable clamping means; and strain measuring means connected to the moveable clamping means for measuring dimensional changes in said strip in response to light absorption of said surface from the illumination source.
Claim 3
Dependent Claim
17 words
A transducer according to claim 3 in which the thickness is from 10 A to 75 μm.
Claim 4
Dependent Claim
26 words
A transducer according to claim 2 in which the ultrathin film is a metal or a natural or a synthetic polymer containing a radiation absorbing pigment.
Claim 5
Dependent Claim
18 words
A transducer according to claim 3 in which the pigment is coated onto a surface of the film.
Claim 6
Dependent Claim
19 words
A transducer according to claim 4 in which the plastic is selected from polyimides, polyesters, polyolefins, polyamides or polycarbonates.
Claim 7
Dependent Claim
20 words
A transducer according to claim 5 in which the absorptive coating has a thickness from 50 A to 1000 A.
Claim 8
Dependent Claim
35 words
A transducer according to claim 6 in which the surface of the film from opposite the illumination source includes a coating of a highly reflective substance having a thickness from 500 A to 5000 A.
Claim 9
Dependent Claim
34 words
A transducer according to claim 7 in which the film is an aromatic polyimide, the absorptive coating is a 100-150 A thick chromium film and the reflective coating is about 1000 A thick aluminum.
Claim 10
Dependent Claim
43 words
A method of detecting illumination comprising the steps of: interposing a photomechanical transducer as defined in claim 1 in the path of the illumination; absorbing radiation from the illumination; and measuring the dimensional change of the film in response to changes in illumination.
Claim 11
Dependent Claim
25 words
A method according to claim 9 in which a fixed strain is applied to the transducer and change of strain of the transducer is measured.
Claim 12
Dependent Claim
49 words
A method of converting light to mechanical energy comprising the steps of: interposing a photomechanical transducer as defined in claim 1 in the path of the light; absorbing radiation from the light; dimensionally changing the transducer in response to the light; and connecting the transducer to a moveable element.
Claim 13
Dependent Claim
19 words
A transducer according to claim 6 in which the absorptive coating is selected from chromium, indium, or tin oxide.
Claim 14
Dependent Claim
40 words
A transducer according to claim 2 in which the film is a linear synthetic polymer film, the absorptive surface comprises a coating of a light absorptive pigment and said film contains a rear surface having a high specular reflectance coating.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-02-24 | 1984-08-25 | 1985-02-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-02-24 | 1988-08-25 | 1989-02-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-02-24 | 1992-08-25 | 1993-02-24 | $7700.00 | Window Closed / Lapsed |