US4201475A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device/process for contact free distance and thickness measurement
Assignee: Siemens AG
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Filing: 1978-04-28
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Granted: 1980-05-06
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Expires: 1998-04-28
Abstract
Abstract A system is disclosed for non-contact distance or thickness measurements. A deflectable laser beam scans the object and produces a measuring impulse during a forward and reverse motion when the laser beam hits a point on an object along a sighting line of a measuring detector. A rectangular pulse is produced from each measuring pulse and rising or falling edges of the rectangular pulse are used for measurement. The impulse widths and possible store times of the evaluation circuitry do not influence the measuring result in the system disclosed.
Inventors
- 👤 Viktor Bodlaj
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:43
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/02; G01B11/06; G01B11/0608
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
266 words
A system for measuring the distance of a point on a surface of an object from a zero plane, comprising: a sharply focused light beam; beam deflector means for periodically deflecting the light beam in one direction and then a reverse direction over a measuring area in which the object is arranged, a point on the object being located on a predetermined line of sight during both directions of scan; a measuring photo-detector means for receiving light only along said predetermined line of sight and for providing a measuring pulse at a measuring time when the point on the object surface is hit by the light beam; means providing a reference pulse at a reference time when said beam deflector means deflects the light beam towards a zero plane point located on said predetermined line of sight; pulse former means for converting measuring pulses of the measuring photo-detector means into rectangular pulses; said measuring photo-detector means producing a first measuring pulse and said pulse former means producing a corresponding first rectangular pulse during deflection movement of the light beam by said deflector means in the one direction; said measuring photo-detector means producing a second measuring pulse and said pulse former means producing a corresponding second rectangular pulse during deflection movement of the light beam by said deflector means in the reverse direction; and means for determining a time difference representative of the distance from a comparison of corresponding same side edges of the first and second rectangular pulses with reference times produced during deflection of the light beam in the one and in the reverse directions.
Claim 2
Independent Claim
266 words
A system for measuring the distance of a point on a surface of an object from a zero plane, comprising: a sharply focused light beam; beam deflector means for periodically deflecting the light beam in one direction and then a reverse direction over a measuring area in which the object is arranged, a point on the object being located on a predetermined line of sight during both directions of scan; a measuring photo-detector means for receiving light only along said predetermined line of sight and for providing a measuring pulse at a measuring time when the point on the object surface is hit by the light beam; means providing a reference pulse at a reference time when said beam deflector means deflects the light beam towards a zero plane point located on said predetermined line of sight; pulse former means for converting measuring pulses of the measuring photo-detector means into rectangular pulses; said measuring photo-detector means producing a first measuring pulse and said pulse former means producing a corresponding first rectangular pulse during deflection movement of the light beam by said deflector means in the one direction; said measuring photo-detector means producing a second measuring pulse and said pulse former means producing a corresponding second rectangular pulse during deflection movement of the light beam by said deflector means in the reverse direction; and means for determining a time difference representative of the distance from a comparison of corresponding same side edges of the first and second rectangular pulses with reference times produced during deflection of the light beam in the one and in the reverse directions.
Claim 3
Dependent Claim
19 words
A system as claimed in claim 1, characterized in that the light deflector means has a stabilized deflection speed.
Claim 4
Dependent Claim
36 words
A system as claimed in claim 1, characterized in that an additional photo-detector means is provided for receiving a sub-light beam gated thereto during deflection movement for measuring a deflection speed of the light deflector means.
Claim 5
Dependent Claim
20 words
A system as claimed in claim 1 wherein said pulse former has a low threshold value, fast switching speed characteristic.
Claim 6
Dependent Claim
16 words
A system as claimed in claim 4 wherein said pulse former means comprises a Schmitt trigger.
Claim 7
Dependent Claim
16 words
A system as claimed in claim 4 wherein said pulse former means comprises a monostable multivibrator.
Claim 8
Dependent Claim
28 words
A system as claimed in claim 1 wherein diaphragm means is employed with the measuring photo-detector means for ensuring reception of light only along the light of sight.
Claim 9
Independent Claim
208 words
A method for measuring the distance of a point on a surface of an object from a zero plane comprising the steps of: providing a sharply focused light beam; periodically deflecting the light beam over a measuring area in which the object is arranged; receiving light only along a predetermined line of sight with a measuring photo-detector; during deflection of the light beam in one direction (i) determining a first reference time when said light beam strikes a reference plane point on said line of sight; (ii) producing a first measuring pulse at a first measuring time when an object surface point located on the line of sight is struck by the light beam; during deflection of the light beam in an opposite direction (i) producing a second measuring pulse at a second measuring time when said object surface point is again struck by the light beam; (ii) determining a second reference time when said light beam again strikes said reference plane point; converting the first and second measuring pulses to first and second rectangular pulses during deflection; and determining a time difference representative of distance from a comparison of the reference times with measuring times corresponding to same side edges of the first and second rectangular pulses.
Claim 10
Independent Claim
208 words
A method for measuring the distance of a point on a surface of an object from a zero plane comprising the steps of: providing a sharply focused light beam; periodically deflecting the light beam over a measuring area in which the object is arranged; receiving light only along a predetermined line of sight with a measuring photo-detector; during deflection of the light beam in one direction (i) determining a first reference time when said light beam strikes a reference plane point on said line of sight; (ii) producing a first measuring pulse at a first measuring time when an object surface point located on the line of sight is struck by the light beam; during deflection of the light beam in an opposite direction (i) producing a second measuring pulse at a second measuring time when said object surface point is again struck by the light beam; (ii) determining a second reference time when said light beam again strikes said reference plane point; converting the first and second measuring pulses to first and second rectangular pulses during deflection; and determining a time difference representative of distance from a comparison of the reference times with measuring times corresponding to same side edges of the first and second rectangular pulses.
Claim 11
Dependent Claim
55 words
The method of claim 8 in which the time difference Δt d , the first measuring time t c , the second measuring time t cr , the first reference time t z , and the second reference time t' z arerelated such that Δt d =t c -t z +t' z -t cr .
References Cited (Backward Citations)
DE2157813A1
Cited
DE2508836A1
Cited
US3923395A
Cited
US4068955A
Cited
US4053234A
Cited
US4111552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-05-06 | 1983-11-05 | 1984-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-05-06 | 1987-11-05 | 1988-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-05-06 | 1991-11-05 | 1992-05-06 | $7700.00 | Window Closed / Lapsed |