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US4484069A
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Apparatus and method for sensing distance
Assignee: ST Regis Paper Co
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Filing: 1981-10-15
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Granted: 1984-11-20
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Expires: 2001-10-15
Abstract
Abstract Apparatus for sensing the distance from a reference point to a remote object comprises a light source and optics to project light from the light source onto the remote object. One component of the optics is a movable mirror which is used to position the projected light on a remote object. A sensor is provided to detect the position of the projected light on the remote object. In response to position information from the sensor, control circuitry produces a drive signal which controls a galvanometer. The galvanometer shaft is attached to rotate the mirror. When the mirror has been positioned such that the projected light impinges on the remote object at a predetermined location, the value of the drive signal can be used to compute the distance to the remote object by triangulation.
Inventors
- 👤 Irving R. Brenholdt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:01
CPC Classifications
G; G01; G01S; G01S17/00; G01S17/02; G01S17/06; G01S17/46; G01S17/48
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
122 words
Apparatus for sensing the distance from a reference point to a remote object comprising: a light source; optical means including a movable mirror for projecting light from said light source onto said remote object; means for sensing the position of said projected light on said remote object; means for moving said mirror; and control means, responsive to said sensing means, for producing a drive signal to cause said moving means to move said mirror until said projected light impinges upon said remote object at a location coincident with a fixed predetermined imaginary line extending from said apparatus toward said object, the value of said drive signal when said light impinges at said location being indicative of the distance to said remote object.
Claim 2
Dependent Claim
122 words
Apparatus for sensing the distance from a reference point to a remote object comprising: a light source; optical means including a movable mirror for projecting light from said light source onto said remote object; means for sensing the position of said projected light on said remote object; means for moving said mirror; and control means, responsive to said sensing means, for producing a drive signal to cause said moving means to move said mirror until said projected light impinges upon said remote object at a location coincident with a fixed predetermined imaginary line extending from said apparatus toward said object, the value of said drive signal when said light impinges at said location being indicative of the distance to said remote object.
Claim 3
Dependent Claim
19 words
The apparatus of claim 1 further comprising an infrared filter disposed between said sensing means and said remote object.
Claim 4
Dependent Claim
19 words
The apparatus of claim 1 further comprising an ultraviolet filter disposed between said sensing means and said remote object.
Claim 5
Dependent Claim
15 words
The apparatus of claim 1 wherein said mirror moves by rotating about an axis thereof.
Claim 6
Dependent Claim
15 words
The apparatus of claim 4 wherein said means for moving said mirror is a galvanometer.
Claim 7
Dependent Claim
17 words
The apparatus of claim 1 or 5 wherein said means for sensing comprises a position sensing photodetector.
Claim 8
Dependent Claim
89 words
The apparatus of claim 1 wherein said sensing means produces first and second output currents, said currents being equal when a light beam is centered on said sensor and unequal when said beam is off-center, and said control means comprises: first and second amplifiers coupled to said first and second outputs respectively, and differential amplifier means for producing said drive signal, said differential amplifier means having a first input coupled to the output of said first amplifier and a second input coupled to the output of said second amplifier.
Claim 9
Dependent Claim
41 words
The apparatus of claim 7 wherein said means for moving said mirror is a galvanometer and further comprising power amplifier means having an input coupled to the output of said differential amplifier means and an output adapted to drive said galvanometer.
Claim 10
Dependent Claim
31 words
The apparatus of claim 7 further comprising means coupled to the outputs of said first and second amplifiers for determining if the sum of said outputs is within a predetermined range.
Claim 11
Dependent Claim
30 words
The apparatus of claim 9 further comprising means coupled to the output of said differential amplifier for determining if the value of said drive signal is within a predetermined range.
Claim 12
Dependent Claim
24 words
The apparatus of claim 7 further comprising means for linearizing the output value of said differential amplifier means by computing the square root thereof.
Claim 13
Dependent Claim
104 words
The apparatus of claim 1 wherein said means for sensing comprises a first position sensing photodetector having at least one lens associated therewith for providing a first, relatively wide field of view, and a second position sensing photodetector having at least one lens assoicated therewith for providing a second, relatively narrow field of view, said first photodetector with said first field of view enabling said control means to provide a drive signal for coarse control of said mirror, and said second photodetector with said second field of view enabling said control means to produce a drive signal for more precise control of said mirror.
Claim 14
Independent Claim
119 words
A method for determining the distance from a reference point to a remote object comprising the steps of: (a) projecting light from a light source, through optical means including an electrically movable mirror, onto a remote object; (b) sensing the position of said projected light on said remote object; (c) producing an electrical signal indicative of said sensed position; (d) moving said mirror in accordance with said electrical signal to re-position said projected light on said remote object at a location coincident with a fixed predetermined imaginary line extending toward said object; and (e) computing the distance to said remote object on the basis of the magnitude of said electrical signal when said projected light is at said location.
Claim 15
Independent Claim
119 words
A method for determining the distance from a reference point to a remote object comprising the steps of: (a) projecting light from a light source, through optical means including an electrically movable mirror, onto a remote object; (b) sensing the position of said projected light on said remote object; (c) producing an electrical signal indicative of said sensed position; (d) moving said mirror in accordance with said electrical signal to re-position said projected light on said remote object at a location coincident with a fixed predetermined imaginary line extending toward said object; and (e) computing the distance to said remote object on the basis of the magnitude of said electrical signal when said projected light is at said location.
Claim 16
Dependent Claim
19 words
The method of claim 13 wherein said sensing step includes the use of at least one position sensing photodetector.
Claim 17
Dependent Claim
25 words
The method of claim 13 or 14 wherein said moving step includes the use of a galvanometer to rotate said mirror about an axis thereof.
Claim 18
Dependent Claim
20 words
The apparatus of claim 1 wherein said imaginary line is the center line of sight of said means for sensing.
Claim 19
Dependent Claim
20 words
The method of claim 14 wherein said imaginary line is the center line of sight of said position sensing photodetector.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-11-20 | 1988-05-21 | 1988-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-11-20 | 1992-05-21 | 1992-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-11-20 | 1996-05-21 | 1996-11-20 | $7700.00 | Window Closed / Lapsed |