US4191473A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and apparatus for measuring the absolute wavelength of a source of unknown frequency radiation
Assignee: Individual
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Filing: 1978-01-09
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Granted: 1980-03-04
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Expires: 1998-01-09
Abstract
Abstract The invention constitutes a method of and apparatus for measuring the absolute wavelength of a source of unknown frequency radiation through directing radiant energy of known frequency against a diffraction grating of predetermined pattern so as to image a calibrated scale on a suitable screen or the like, and then directing the radiant energy from the unknown frequency source along the same path to the diffraction grating and onto the screen, where a visually available easy-to-read measurement of the wavelength appears.
Inventors
- 👤 Theodor W. Hansch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 21:18
CPC Classifications
G; G01; G01J; G01J9/00; G01J3/00; G01J3/12; G01J3/18; G01J3/28; G01J2003/2866
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
82 words
Apparatus for measuring the absolute wavelength of a source of unknown frequency radiation which comprises a diffraction grating having a predetermined grating pattern with periodic variations in at least some of its grating lines and arranged to receive radiation from the radiation source, a reference source of radiation of known wavelength (frequency) arranged to direct its radiation against said diffraction grating, and means for imaging the diffracted radiation from both sources, the imaged radiation from said reference source providing a calibration scale.
Claim 2
Dependent Claim
82 words
Apparatus for measuring the absolute wavelength of a source of unknown frequency radiation which comprises a diffraction grating having a predetermined grating pattern with periodic variations in at least some of its grating lines and arranged to receive radiation from the radiation source, a reference source of radiation of known wavelength (frequency) arranged to direct its radiation against said diffraction grating, and means for imaging the diffracted radiation from both sources, the imaged radiation from said reference source providing a calibration scale.
Claim 3
Dependent Claim
31 words
Apparatus for measuring absolute wavelength according to claim 1 wherein said diffraction grating has predetermined variations in the characteristics of its grating lines, such as length, width, phase and the like.
Claim 4
Dependent Claim
17 words
Apparatus for measuring absolute wavelength according to claim 2 wherein said line variations constitute different line lengths.
Claim 5
Dependent Claim
17 words
Apparatus for measuring absolute wavelength according to claim 2 wherein said line variations constitute different line widths.
Claim 6
Dependent Claim
34 words
Apparatus for measuring absolute wavelength according to claim 1 wherein the grating lines on said diffraction grating are spaced to provide a calibration scale in a whole number of angstroms at said imaging means.
Claim 7
Dependent Claim
23 words
Apparatus for measuring absolute wavelength according to claim 1 which comprises means for masking some of the grating lines on said diffraction grating.
Claim 8
Dependent Claim
23 words
Apparatus for measuring absolute wavelength according to claim 1 wherein said diffraction grating has grating lines with different spacings on different areas thereof.
Claim 9
Dependent Claim
26 words
Apparatus for measuring absolute wavelength according to claim 1 wherein both sources of radiation traverse a common path through at least a portion of their travel.
Claim 10
Dependent Claim
17 words
Apparatus for measuring absolute wavelength according to claim 1 wherein said diffraction grating constitutes a holographic grating.
Claim 11
Dependent Claim
21 words
Apparatus for measuring absolute wavelength according to claim 9 wherein said holographic grating includes indicia for presentation on said imaging means.
Claim 12
Independent Claim
66 words
The method of measuring the absolute wavelength of a source of unknown frequency radiation which comprises the steps of positioning a diffraction grating in the path of radiation from the unknown source, imaging radiation dispersed from the diffraction grating, and directing a source of known frequency radiation against the diffraction grating to provide a wavelength calibration scale superimposed on the imaged radiation source of unknown frequency.
Claim 13
Independent Claim
66 words
The method of measuring the absolute wavelength of a source of unknown frequency radiation which comprises the steps of positioning a diffraction grating in the path of radiation from the unknown source, imaging radiation dispersed from the diffraction grating, and directing a source of known frequency radiation against the diffraction grating to provide a wavelength calibration scale superimposed on the imaged radiation source of unknown frequency.
Claim 14
Dependent Claim
49 words
A diffraction grating which comprises a plate, and means forming a plurality of grooves on said plate in a predetermined pattern so as to produce a divided wavelength scale when illuminated by a reference source of radiation, said predetermined pattern including grooves with a periodic variation in groove characteristics.
Claim 15
Dependent Claim
49 words
A diffraction grating which comprises a plate, and means forming a plurality of grooves on said plate in a predetermined pattern so as to produce a divided wavelength scale when illuminated by a reference source of radiation, said predetermined pattern including grooves with a periodic variation in groove characteristics.
Claim 16
Dependent Claim
19 words
A diffraction grating according to claim 12 wherein said variation constitutes a variation in groove length at decimal intervals.
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) | 1983-03-04 | 1983-09-03 | 1984-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-03-04 | 1987-09-03 | 1988-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-03-04 | 1991-09-03 | 1992-03-04 | $7700.00 | Window Closed / Lapsed |