US5039222A
Expired / Lapsed
US
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Apparatus and method for producing fourier transform spectra for a test object in fourier transform spectrographs
Assignee: Fuji Electric Co Ltd
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Filing: 1989-07-17
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Granted: 1991-08-13
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Expires: 2009-07-17
Abstract
Abstract Apparatus and a method for producing Fourier spectra for a test object utilizing a plurality of laser interference signals each having a period corresponding to a wavelength of a laser beam and being out of phase by 1/n of the wavelength of the laser beam, n being a positive integer above 1. An infrared interference signal representing the test object after the test object is irradiated with an infrared light beam is sampled at a time interval corresponding to 1/n of the wavelength of the at least one laser interference signal and n sets of sampled data corresponding to the infrared interference signal are produced. Each set of sampled data is Fourier-transformed independently from the other to generate a Fourier spectrum corresponding to each set. All of the independently generated Fourier spectra are later combined to produce a Fourier spectrum corresponding to the infrared interference signal.
Inventors
- 👤 Akio Izumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 05:50
CPC Classifications
G; G01; G01J; G01J3/00; G01J3/28; G01J3/45; G01J3/453
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
209 words
Apparatus for producing an analysis spectrum for a test object, comprising: first and second light sources for generating first and second light beams, respectively; means, coupled to the first light source, for generating one or more first interference signals having a time period corresponding to the wavelength of the first light beam; means, coupled to the second light source, for irradiating the test object with the second light beam to obtain characteristics of the test object; means, coupled to the irradiating means, for generating a second interference signal representing an irradiated test object; means, coupled to said first and second interference signal generating means, for sampling the second interference signal at a time interval corresponding to 1/n of said time period of the first interference signal to produce sampled data representing the second interference signal; means, coupled to said sampling means, for producing n sets of data, each set containing data representing the sampled data at every nth time interval, n being a positive integer greater than unity; means, coupled to said producing means, for individually generating an analysis spectrum corresponding to said each set of data; and means for combining all of the individually generated analysis spectra to produce a resultant analysis spectrum representing the second interference signal.
Claim 2
Dependent Claim
209 words
Apparatus for producing an analysis spectrum for a test object, comprising: first and second light sources for generating first and second light beams, respectively; means, coupled to the first light source, for generating one or more first interference signals having a time period corresponding to the wavelength of the first light beam; means, coupled to the second light source, for irradiating the test object with the second light beam to obtain characteristics of the test object; means, coupled to the irradiating means, for generating a second interference signal representing an irradiated test object; means, coupled to said first and second interference signal generating means, for sampling the second interference signal at a time interval corresponding to 1/n of said time period of the first interference signal to produce sampled data representing the second interference signal; means, coupled to said sampling means, for producing n sets of data, each set containing data representing the sampled data at every nth time interval, n being a positive integer greater than unity; means, coupled to said producing means, for individually generating an analysis spectrum corresponding to said each set of data; and means for combining all of the individually generated analysis spectra to produce a resultant analysis spectrum representing the second interference signal.
Claim 3
Dependent Claim
9 words
The apparatus of claim 1, where n is 2.
Claim 4
Dependent Claim
9 words
The apparatus of claim 1, where n is 3.
Claim 5
Dependent Claim
14 words
The apparatus of claim 1, wherein the first light beam is a laser beam.
Claim 6
Dependent Claim
15 words
The apparatus of claim 1 wherein said second light beam is an infrared light beam.
Claim 7
Dependent Claim
82 words
The apparatus of claim 2, wherein the means for sampling the second interference signal includes a pair of flip-flops, each producing a sample-and-hold control signal having a wavelength substantially equal to the time period of the first interference signal and being out of phase by 1/2 of the time period with respect to the other, the second interference signal being sampled by each of the sample-and-hold control signals at a time interval corresponding to the phase of a respective sample-and-hold control signal.
Claim 8
Dependent Claim
52 words
The apparatus of claim 1, wherein the one or more first interference signal comprises m first interference signals, m being positive inter about 1, said m first interference signals being out of phase with respect to one another by 1/m of the time period of one of the m first interference signals.
Claim 9
Dependent Claim
29 words
The apparatus of claim 7, wherein said means for sampling the second interference signal includes m flip-flops each corresponding to a respective one of the m first interference signals.
Claim 10
Dependent Claim
20 words
The apparatus of claim 7, further comprising a quarter wavelength plate for effecting the polarization of the first light beam.
Claim 11
Dependent Claim
32 words
The apparatus of claim 3, further comprising m beam splitters for splitting the first light beam into m light beams each corresponding to a respective one of the m first interference signals.
Claim 12
Dependent Claim
44 words
The apparatus of claim 10, further comprising m sets of analyzer and detector each set corresponding to a respective one of the m light beams for analyzing a respective incoming light beam and converting the analyzed light beam into a corresponding first interference signal.
Claim 13
Dependent Claim
12 words
The apparatus of claim 1, wherein the analysis spectrum is Fourier spectrum.
Claim 14
Dependent Claim
11 words
The apparatus of claim 7, wherein said integer m is three(3).
Claim 15
Dependent Claim
30 words
The apparatus of claim 13, wherein said means for sampling the second interference signal includes three (3) flip-flops each corresponding to a respective one of the three first interference signals.
Claim 16
Independent Claim
146 words
A method for producing an analysis spectrum for a test object, comprising: generating one or more first interference signals having a time period corresponding to the wavelength of a first light beam; irradiating the test object with a second light beam to obtain characteristics of the test object; generating a second interference signal responsive representing the irradiated test object; sampling the second interference signal at a time interval corresponding to 1/n of the time period of the first interference signal to produce sampled data representing the second interference signal; producing n sets of data, each set containing data representing the sampled data at every nth time interval, n being a positive integer greater than unity; individually generating an analysis spectrum corresponding to said each set of data; and combining all of the individually generated analysis spectra to produce an analysis spectrum representing the second interference signal.
Claim 17
Independent Claim
146 words
A method for producing an analysis spectrum for a test object, comprising: generating one or more first interference signals having a time period corresponding to the wavelength of a first light beam; irradiating the test object with a second light beam to obtain characteristics of the test object; generating a second interference signal responsive representing the irradiated test object; sampling the second interference signal at a time interval corresponding to 1/n of the time period of the first interference signal to produce sampled data representing the second interference signal; producing n sets of data, each set containing data representing the sampled data at every nth time interval, n being a positive integer greater than unity; individually generating an analysis spectrum corresponding to said each set of data; and combining all of the individually generated analysis spectra to produce an analysis spectrum representing the second interference signal.
Claim 18
Dependent Claim
9 words
The method of claim 15, where n is 2.
Claim 19
Dependent Claim
9 words
The method of claim 15, where n is 3.
Claim 20
Dependent Claim
14 words
The method of claim 15, wherein the first light beam is a laser beam.
Claim 21
Dependent Claim
15 words
The method of claim 15, wherein the second light beam is an infrared light beam.
Claim 22
Dependent Claim
81 words
The method of claim 15, wherein the step of sampling the second interference signal includes generating a pair of sample-and-hold control signals having a time period substantially equal to the time period of the first interference signal and being out of phase by 1/2 of the time period with respect to the other, and sampling the second interference signal with each of the generated sample-and-hold control signals at a time interval corresponding to the phase of a respective sample-and-hold control signal.
Claim 23
Dependent Claim
58 words
The method of claim 15, wherein the step of generating one or more first interference signal include generating m first interference signals, m being positive integer above 1, each of the m first interference signals being out of phase with respect to one another by 1/m of the time period of one of said m first interference signals.
Claim 24
Dependent Claim
38 words
The method of claim 21, wherein the step of generating one or more first interference signal further includes splitting the first light beam into m light beams each corresponding to a respective one of the first interference signals.
Claim 25
Dependent Claim
13 words
The method of claim 15, wherein the analysis spectrum is a Fourier spectrum.
Claim 26
Dependent Claim
12 words
The method of claim 21, wherein said integer m is three (3).
Claim 27
Dependent Claim
39 words
The method of claim 24, wherein the step of generating one or more first interference signal includes splitting the first light beam into three (3) light beams each corresponding to a respective one of the three first interference signals.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1994-08-12 | 1995-02-11 | 1995-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-12 | 1999-02-11 | 1999-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-12 | 2003-02-11 | 2003-08-13 | $7700.00 | Window Closed / Lapsed |