US5585913A
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US
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Ultrashort pulsewidth laser ranging system employing a time gate producing an autocorrelation and method therefore
Assignee: Aisin Corp
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Filing: 1994-04-01
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Granted: 1996-12-17
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Expires: 2014-04-01
Abstract
Abstract An optical correlator is disclosed which, in combination with an ultrafast optical pulsed source, can be used for estimating distances of objects with submicron precision. The system includes at least one ultrafast pulsed laser source feeding into an amplitude-division device, an entity for launching pulsed radiation at the target along with an entity for collecting the radiation scattered or reflected off the surface of the object, a nonlinear device for timegating the collected signal with the amplitude-divided source, and a detection device for observing the timegated signal.
Inventors
- 👤 Anand Hariharan
- 👤 Donald J. Harter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:12
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/23; H01S3/2383; G; G01; G01P; G01P3/00; G01P3/64; G01P3/80; G01P3/806; G01R; G01R13/00; G01R13/20; G01R13/22; G01R13/34; G01R13/347; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/08; G01S17/10; G01S17/18; G01S17/50; G01S7/00; G01S7/48; G01S7/483; G01S7/484; G01S7/486
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
112 words
An apparatus for measuring a distance to at least one object, comprising: at least first and second distinct source means for generating pulsed light beams of ultrashort pulsewidth; means for directing a first, measurement beam to said object and collecting a reflected beam; means for directing a second, reference beam along a reference optical path; means for controlling repetition rates of said first and second source means, so as to control a frequency of temporal coincidence of said pulsed light beams; means for combining said reference and reflected beams and directing said beams to a timegate; and means for determining a distance to said object from the output generated by said timegate.
Claim 2
Independent Claim
112 words
An apparatus for measuring a distance to at least one object, comprising: at least first and second distinct source means for generating pulsed light beams of ultrashort pulsewidth; means for directing a first, measurement beam to said object and collecting a reflected beam; means for directing a second, reference beam along a reference optical path; means for controlling repetition rates of said first and second source means, so as to control a frequency of temporal coincidence of said pulsed light beams; means for combining said reference and reflected beams and directing said beams to a timegate; and means for determining a distance to said object from the output generated by said timegate.
Claim 3
Dependent Claim
30 words
An apparatus as claimed in claim 1, wherein said combining means directs said beams to said timegate in parallel fashion, and including means for overlapping said beams within said timegate.
Claim 4
Dependent Claim
15 words
An apparatus as claimed in claim 2, wherein said timegate comprises a non-linear optical crystal.
Claim 5
Dependent Claim
29 words
An apparatus as claimed in claim 1, wherein said distance determining means includes means for comparing a time-of-flight of said reference beam with a time-of-flight of said measurement beam.
Claim 6
Dependent Claim
49 words
An apparatus as claimed in claim 1, wherein said timegate comprises a non-linear frequency doubling crystal, which, when said reference beam and said measurement beam are applied thereto, produces an autocorrelation function of said beams having maxima at locations where the pulses of said beams are coincident in time.
Claim 7
Independent Claim
92 words
An apparatus for measuring a distance to at least one object, comprising: at least first and second distinct source means for generating pulsed light beams of ultrashort pulsewidth, at at least two distinct wavelengths; means for directing a first, measurement beam to said object and collecting a reflected beam; means for directing a second, reference beam along a reference optical path; means for combining said reference and reflected beams and directing said beams to a timegate; and means for determining a distance to said object from the output generated by said timegate.
Claim 8
Independent Claim
92 words
An apparatus for measuring a distance to at least one object, comprising: at least first and second distinct source means for generating pulsed light beams of ultrashort pulsewidth, at at least two distinct wavelengths; means for directing a first, measurement beam to said object and collecting a reflected beam; means for directing a second, reference beam along a reference optical path; means for combining said reference and reflected beams and directing said beams to a timegate; and means for determining a distance to said object from the output generated by said timegate.
Claim 9
Dependent Claim
30 words
An apparatus as claimed in claim 6, wherein said combining means directs said beams to said timegate in parallel fashion, and including means for overlapping said beams within said timegate.
Claim 10
Dependent Claim
15 words
An apparatus as claimed in claim 7, wherein said timegate comprises a non-linear optical crystal.
Claim 11
Dependent Claim
18 words
An apparatus as claimed in claim 8, wherein said timegate timegates the input signals on a subpicosecond timescale.
Claim 12
Dependent Claim
33 words
An apparatus as claimed in claim 9, wherein said timegate outputs a timegate signal proportional to both the reflected beam and to a time-correlation product of the reflected beam and the reference beam.
Claim 13
Dependent Claim
23 words
An apparatus as claimed in claim 10, wherein said timegate timegates virtually an entire photon energy of the reflected beam, providing high sensitivity.
Claim 14
Dependent Claim
23 words
An apparatus as claimed in claim 8, wherein said optical crystal is comprised of a beta-barium borate crystal approximately 1.0 mm in thickness.
Claim 15
Dependent Claim
21 words
An apparatus as claimed in claim 8, wherein said means for combining comprises a lens having a relatively short focal length.
Claim 16
Dependent Claim
29 words
An apparatus as claimed in claim 6, wherein said distance determining means includes means for comparing a time-of-flight of said reference beam with a time-of-flight of said measurement beam.
Claim 17
Dependent Claim
49 words
An apparatus as claimed in claim 6, wherein said timegate comprises a non-linear frequency doubling crystal, which, when said reference beam and said measurement beam are applied thereto, produces an autocorrelation function of said beams having maxima at locations where the pulses of said beams are coincident in time.
Claim 18
Dependent Claim
29 words
An apparatus as claimed in claim 6, further comprising an aperture for rejecting extraneous light from the combined reference and reflected beams, including second harmonics of the combined beams.
Claim 19
Dependent Claim
18 words
An apparatus as claimed in claim 6, wherein said ultrashort pulsewidth is on the order of 100 fs.
Claim 20
Dependent Claim
14 words
An apparatus as claimed in claim 6, wherein said object has a rough component.
Claim 21
Dependent Claim
14 words
An apparatus as claimed in claim 6, wherein said object has an unclear component.
Claim 22
Dependent Claim
14 words
An apparatus as claimed in claim 6, wherein said object is a rotating shaft.
Claim 23
Dependent Claim
14 words
An apparatus as claimed in claim 6, wherein said object is a vibrating element.
Claim 24
Independent Claim
143 words
An apparatus for measuring an instantaneous distance to, or tracking the motions of, a vibratory object, comprising: means for generating a pulsed light beam of ultrashort pulsewidth; means for dividing said light beam into a reference beam and a measurement beam; means for directing said measurement beam to said object and collecting a reflected beam; means for combining said reference and reflected beams and directing said beams to a timegate; means for determining a distance to said object from the output generated by said timegate; said reference beam traveling along a reference path of fixed length, and said measurement beam traveling along a measurement path having a length which varies with the vibration of said object; said distance determining means including means for mathematically fitting successive autocorrelation maxima to a sinusoidal function to thereby determine at least a vibrational frequency of said object.
Claim 25
Independent Claim
143 words
An apparatus for measuring an instantaneous distance to, or tracking the motions of, a vibratory object, comprising: means for generating a pulsed light beam of ultrashort pulsewidth; means for dividing said light beam into a reference beam and a measurement beam; means for directing said measurement beam to said object and collecting a reflected beam; means for combining said reference and reflected beams and directing said beams to a timegate; means for determining a distance to said object from the output generated by said timegate; said reference beam traveling along a reference path of fixed length, and said measurement beam traveling along a measurement path having a length which varies with the vibration of said object; said distance determining means including means for mathematically fitting successive autocorrelation maxima to a sinusoidal function to thereby determine at least a vibrational frequency of said object.
Claim 26
Independent Claim
166 words
An apparatus for measuring an instantaneous distance to, or tracking the motion of, a rotating object, comprising: means for generating a pulsed light beam of ultrashort pulsewidth; means for dividing said light beam into a reference beam and a measurement beam; means for directing said measurement beam to said object and collecting a reflected beam; means for combining said reference and reflected beams and directing said beams to a timegate; means for determining a distance to said object from the output generated by said timegate; and wherein said reference beam travels along a reference path of fixed length, and wherein said measurement beam travels along a measurement path having a length which varies with the movement of said object; said rotating object comprising a rotating body having at least one portion susceptible to reflection/scatter of said measurement beam as said object rotates, and said distance determining means including means for calculating a velocity value in accordance with the timing of the reflection of said measurement beam.
Claim 27
Independent Claim
166 words
An apparatus for measuring an instantaneous distance to, or tracking the motion of, a rotating object, comprising: means for generating a pulsed light beam of ultrashort pulsewidth; means for dividing said light beam into a reference beam and a measurement beam; means for directing said measurement beam to said object and collecting a reflected beam; means for combining said reference and reflected beams and directing said beams to a timegate; means for determining a distance to said object from the output generated by said timegate; and wherein said reference beam travels along a reference path of fixed length, and wherein said measurement beam travels along a measurement path having a length which varies with the movement of said object; said rotating object comprising a rotating body having at least one portion susceptible to reflection/scatter of said measurement beam as said object rotates, and said distance determining means including means for calculating a velocity value in accordance with the timing of the reflection of said measurement beam.
References Cited (Backward Citations)
US3669541A
Cited
US4097148A
Cited
US4377036A
Cited
US4619529A
Cited
US4767210A
Cited
US4830486A
Cited
US4606639A
Cited
US4660978A
Cited
US4708481A
Cited
US4729653A
Cited
US4767197A
Cited
US4978219A
Cited
US5037206A
Cited
US4886363A
Cited
US5050988A
Cited
US5170217A
Cited
US4973160A
Cited
US5106191A
Cited
US5166751A
Cited
US5189489A
Cited
US5172186A
Cited
US5194918A
Cited
US5299170A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-12-17 | 2000-06-17 | 2000-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-12-17 | 2004-06-17 | 2004-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-12-17 | 2008-06-17 | 2008-12-17 | $7700.00 | Window Closed / Lapsed |