US3788746A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical dilatometer
Assignee: HP Inc
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Filing: 1972-10-02
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Granted: 1974-01-29
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Expires: 1992-10-02
Abstract
Abstract A dilatometer for measuring the linear coefficient of expansion of a specimen block wrung on a platen. The measurement is made by electronically comparing a set of fringes that are responsive to motion of the sample to a set of fringes that are responsive to motion of the platen. Each set of fringes is generated by interference between a reference light beam and a light beam which has twice traversed the distance to the surface whose motion is being monitored, the two traversals being along separate but parallel paths. Each of the two sets of fringes is generated at the surface of the main beam splitter by recombining beams which have been reflected from cube-corners so that there is no requirement for a separate, precisely aligned, output beam splitter.
Inventors
- 👤 R Baldwin
- 👤 B Ruff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:12
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02; G01B9/02001; G01B9/02007; G01B9/02002; G01N; G01N25/00; G01N25/16; G01B2290/00; G01B2290/45; G01B2290/70
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
295 words
A dilatometer comprising: source means for producing a light beam; a first beam splitter for splitting the light beam into two beams, and for directing each of these two beams along a different optical path; optical means including a second beam splitter for splitting one of said two beams into a first component and a second component, directing said first component to the surface of a specimen on a platen in such a way that said first component traverses the round trip distance to said specimen twice along separate but parallel paths, and directing said second component along a first reference path in such a way that after traversing said first reference path said second component optically interferes with said first component at said second beam splitter; said optical means also being operable for splitting the other of said two beams into a third component and a fourth component, directing said third component to the surface of said platen in such a way that said third component traverses the round trip distance to said platen twice along separate but parallel paths, and for directing said fourth component along a second reference path in such a way that after traversing said second reference path said fourth component optically interferes with said third component at the beam splitting surface of said second beam splitter; first detection means for detecting optical fringes produced by optical interference of said first and second components; second detection means for detecting optical fringes produced by the optical interference of said third and fourth components; and output means for comparing outputs of said first and second detection means, and producing an output responsive to the absolute displacement of the surface of said simple less the absolute displacement of the surface of said platen.
Claim 2
Dependent Claim
295 words
A dilatometer comprising: source means for producing a light beam; a first beam splitter for splitting the light beam into two beams, and for directing each of these two beams along a different optical path; optical means including a second beam splitter for splitting one of said two beams into a first component and a second component, directing said first component to the surface of a specimen on a platen in such a way that said first component traverses the round trip distance to said specimen twice along separate but parallel paths, and directing said second component along a first reference path in such a way that after traversing said first reference path said second component optically interferes with said first component at said second beam splitter; said optical means also being operable for splitting the other of said two beams into a third component and a fourth component, directing said third component to the surface of said platen in such a way that said third component traverses the round trip distance to said platen twice along separate but parallel paths, and for directing said fourth component along a second reference path in such a way that after traversing said second reference path said fourth component optically interferes with said third component at the beam splitting surface of said second beam splitter; first detection means for detecting optical fringes produced by optical interference of said first and second components; second detection means for detecting optical fringes produced by the optical interference of said third and fourth components; and output means for comparing outputs of said first and second detection means, and producing an output responsive to the absolute displacement of the surface of said simple less the absolute displacement of the surface of said platen.
Claim 3
Dependent Claim
239 words
A dilatometer as in claim 1 wherein: said source means comprises a two-frequency laser producing a two-frequency light beam with a first linearly polarized component beam of a first frequency, and a second orthogonally linearly polarized component beam of a second frequency; said optical means comprises a polarizing beam splitter for splitting each of said two beams into its two linearly polarized component beams, a first cube-corner reflector for reflecting said second and fourth component beams in said first and second reference paths, a second cube-corner reflector and a quarter wave plate for directing said first component beam to the surface of said platen and saiD third component beam to the surface of said sample; said first and second detection means each comprise a polarizing analyzer and mixing means for producing an output signal whose frequency is the difference between the two frequencies of said two-frequency beam, doppler shifted in response to the motion of the surface of the platen in the case of said first detection means, and responsive to the motion of the surface of said sample in the case of said second detection means; and said output means comprises a reversible counter for counting in one direction the frequency of the output of said first detection means, counting in another direction the frequency of the output of said second detection means, and producing an output which is the accumulated difference of the counts in each direction.
Claim 4
Dependent Claim
82 words
A dilatometer as in claim 2, wherein: said output means includes an electronic resolution extender for multiplying the doppler shift contribution to the output of said first detection means by a selected factor, multiplying the doppler shift contribution to the output of said second detection means by said selected factor minus one; and said reversible counter counts in one direction the frequency of the output of said resolution extender and counts in the other direction the output of said second detection means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |