Patent US5594543A successfully refreshed from Google Patents.
US5594543A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser diode radar with extended range
Assignee: Goodrich Corp
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Filing: 1990-01-16
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Granted: 1997-01-14
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Expires: 2010-01-16
Abstract
Abstract An optical radar system includes a laser diode and an external cavity formed by a partial reflector for reflecting a first portion of the laser beam back into the diode. A second portion of the beam is passed out of the external cavity for backscatter thereof from a target back into the diode. The emission thereby has a beat frequency related to the velocity of the target. A frequency chirp is introduced by mechanically oscillating the partial reflector longitudinally resulting in a modulation frequency in the emission corresponding to the range of the target. A photodetector and processor are used to determine the velocity and range.
Inventors
- 👤 Peter de Groot
- 👤 Gregg M. Gallatin
- 👤 Chandra Roychoudhuri
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:57
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/50; G01S17/58; G01S17/06; G01S17/08; G01S17/10; G01S17/26; G01S7/00; G01S7/48; G01S7/481; G01S7/4811; G01S7/491; G01S7/4912; G01S7/4916
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
125 words
An optical radar system with an extended range, comprising: a laser diode for producing laser emission including a laser beam; external cavity means receptive of the beam, including a partial reflector spaced from the laser diode for reflecting a first portion of the beam back into the laser diode, the partial reflector passing a second portion of the beam out of the external cavity so as to allow backscatter of the second portion from a target object back through the partial reflector into the laser diode, whereby the emission has a modulation associated with spatial information on the target object; a photodetector responsive to the emission for generating a signal representing the modulation; and processing means receptive of the signal for computing the spatial information.
Claim 2
Dependent Claim
125 words
An optical radar system with an extended range, comprising: a laser diode for producing laser emission including a laser beam; external cavity means receptive of the beam, including a partial reflector spaced from the laser diode for reflecting a first portion of the beam back into the laser diode, the partial reflector passing a second portion of the beam out of the external cavity so as to allow backscatter of the second portion from a target object back through the partial reflector into the laser diode, whereby the emission has a modulation associated with spatial information on the target object; a photodetector responsive to the emission for generating a signal representing the modulation; and processing means receptive of the signal for computing the spatial information.
Claim 3
Dependent Claim
57 words
The optical radar system according to claim 1 wherein the laser diode has an front facet for passing the beam from the diode, and the cavity means further includes a lens disposed in the beam between the partial reflector and the front facet, the lens having conjugate foci respectively at the partial reflector and the front facet.
Claim 4
Dependent Claim
17 words
The optical radar system according to claim 1 wherein the partial reflector comprises a partially reflective mirror.
Claim 5
Dependent Claim
57 words
The optical radar system according to claim 1 wherein the laser diode is a single-mode type laser diode, the system further comprises power supply means for driving the laser diode in substantially single mode operation, and the partial reflector is spaced from the laser diode by a cavity distance less than a critical distance of multimode operation.
Claim 6
Dependent Claim
20 words
The optical radar system according to claim 4 wherein the cavity distance is between about 1 cm and 15 cm.
Claim 7
Dependent Claim
24 words
The optical radar system according to claim 1 further comprising objective means for focusing the second portion of the beam on the target object.
Claim 8
Dependent Claim
78 words
The optical radar system according to claim 6 wherein the laser diode has an front facet for passing the beam from the diode, and the cavity means further includes a lens disposed in the beam between the partial reflector and the front facet, the lens having conjugate foci respectively at the partial reflector and the front facet and the objective means comprises an objective lens with conjugate foci positioned respectively at the partial reflector and the target object.
Claim 9
Dependent Claim
38 words
The optical radar system according to claim 1 wherein the modulation comprises a beat frequency in the emission corresponding to velocity of the target object relative to the laser diode, and the spatial information computed includes the velocity.
Claim 10
Dependent Claim
66 words
The optical radar system according to claim 8 further comprising chirp means for effecting a frequency chirp in the emission such that the emission has a further modulation associated with spatial information on the target object, the further modulation being a modulation frequency in the emission corresponding to range of the target object from the laser diode, and the spatial information computed further includes the range.
Claim 11
Dependent Claim
47 words
The optical radar system according to claim 9 wherein the chirp means comprises oscillator means for mechanically oscillating the partial reflector longitudinally with respect to the beam so that the first portion of the beam reflected into the laser diode effects the frequency chirp in the emission.
Claim 12
Dependent Claim
31 words
The optical radar system according to claim 9 further comprising focusing means receptive of the spatial information on distance for focusing the second portion of the beam on the target object.
Claim 13
Dependent Claim
50 words
The optical radar system according to claim 1 further comprising chirp means for effecting a frequency chirp in the emission such that the modulation comprises a modulation frequency in the emission corresponding to range of the target object from the laser diode, and the spatial information computed includes the range.
Claim 14
Dependent Claim
47 words
The optical radar system according to claim 12 wherein the chirp means comprises oscillator means for mechanically oscillating the partial reflector longitudinally with respect to the beam so that the first portion of the beam reflected into the laser diode effects the frequency chirp in the emission.
Claim 15
Dependent Claim
31 words
The optical radar system according to claim 12 further comprising focusing means receptive of the spatial information on distance for focusing the second portion of the beam on the target object.
Claim 16
Independent Claim
130 words
A method of measuring spatial information on a target object, comprising: providing an optical radar system having a laser diode for producing laser emission including a laser beam, and further having an external cavity with a partial reflector spaced from the laser diode, the external cavity being receptive of the beam; reflecting a first portion of the beam from the reflector back into the laser diode; passing a second portion of the beam out of the external cavity to a target object; directing backscatter of the beam from the target object back through the partial reflector into the laser diode to effect a modulation of the emission associated with spatial information on the target object; detecting the modulation; and computing from the modulation the spatial information on the target object.
Claim 17
Independent Claim
130 words
A method of measuring spatial information on a target object, comprising: providing an optical radar system having a laser diode for producing laser emission including a laser beam, and further having an external cavity with a partial reflector spaced from the laser diode, the external cavity being receptive of the beam; reflecting a first portion of the beam from the reflector back into the laser diode; passing a second portion of the beam out of the external cavity to a target object; directing backscatter of the beam from the target object back through the partial reflector into the laser diode to effect a modulation of the emission associated with spatial information on the target object; detecting the modulation; and computing from the modulation the spatial information on the target object.
Claim 18
Dependent Claim
56 words
The method according to claim 15 wherein the laser diode has a front facet for passing the beam from the diode, and the external cavity has therein a lens disposed in the beam between the partial reflector and the front facet, the lens having conjugate foci positioned respectively at the partial reflector and the front facet.
Claim 19
Dependent Claim
15 words
The method according to claim 15 wherein the partial reflector comprises a partially reflective mirror.
Claim 20
Dependent Claim
58 words
The method according to claim 1 wherein the laser diode is a single-mode type laser diode, and the method further comprises providing a driver current so as to operate the laser diode in substantially single mode operation, and spacing the partial reflector from the laser diode by a cavity distance less than a critical distance of multimode operation.
Claim 21
Dependent Claim
18 words
The method according to claim 18 wherein the cavity distance is between about 1 cm and 15 cm.
Claim 22
Dependent Claim
18 words
The method according to claim 18 further comprising operating the laser diode with a current near threshold current.
Claim 23
Dependent Claim
25 words
The method according to claim 20 wherein the current is such as to operate the laser diode between about 1% and 5% of rated power.
Claim 24
Dependent Claim
18 words
The method according to claim 15 further comprising operating the laser diode with a current near threshold current.
Claim 25
Dependent Claim
25 words
The method according to claim 22 wherein the current is such as to operate the laser diode between about 1% and 5% of rated power.
Claim 26
Dependent Claim
19 words
The method according to claim 15 further comprising focusing the second portion of the beam on the target object.
Claim 27
Dependent Claim
36 words
The method according to claim 15 wherein the modulation comprises a beat frequency in the emission corresponding to velocity of the target object relative to the laser diode, and the spatial information computed includes the velocity.
Claim 28
Dependent Claim
61 words
The method according to claim 25 further comprising effecting a frequency chirp in the emission such that the emission has a further modulation associated with spatial information on the target object, the further modulation being a modulation frequency in the emission corresponding to range of the target object from the laser diode, and the spatial information computed further includes the range.
Claim 29
Dependent Claim
45 words
The optical radar system according to claim 26 wherein the step of effecting a frequency chirp comprises mechanically oscillating the partial reflector longitudinally with respect to the beam so that the first portion of the beam reflected into the laser diode effects the frequency chirp.
Claim 30
Dependent Claim
27 words
The method according to claim 27 further comprising utilizing the spatial information on the range for focusing the second portion of the beam on the target object.
Claim 31
Dependent Claim
47 words
The method according to claim 15 further comprising effecting a frequency chirp in the emission such that the modulation comprises a modulation frequency in the emission corresponding to a range of the target object from the laser diode, and the spatial information computed further includes the distance.
Claim 32
Dependent Claim
43 words
The method according to claim 29 wherein the step of effecting a frequency chirp comprises mechanically oscillating the partial reflector longitudinally with respect to the beam so that the first portion of the beam reflected into the laser diode effects the frequency chirp.
Claim 33
Dependent Claim
27 words
The method according to claim 29 further comprising utilizing the spatial information on the range for focusing the second portion of the beam on the target object.
Claim 34
Dependent Claim
24 words
The optical radar system according to claim 1 wherein the photodetector is disposed to receive a portion of the emission separate from the beam.
Claim 35
Dependent Claim
26 words
The method according to claim 15 wherein the modulation is detected by a photodetector disposed to receive a portion of the emission separate from the beam.
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) | 2000-01-14 | 2000-07-15 | 2001-01-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-01-14 | 2004-07-15 | 2005-01-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-01-14 | 2008-07-15 | 2009-01-14 | $7700.00 | Window Closed / Lapsed |