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US3700903A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical detecting systems for sensing variations in the lateral motion of light rays
Assignee: Zenith Electronics LLC
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Filing: 1970-12-09
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Granted: 1972-10-24
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Expires: 1990-12-09
Abstract
Abstract An instrument is described which renders Rayleigh or surface waves visible on a television screen. A flying spot scanner uses a laser beam to scan a substrate horizontally and vertically at standard television rates. The periodic tilting or warping of the surface caused by the passage of an acoustic wave modulates the light reflected from the surface. This modulation is picked up by a photocell, filtered, amplified and heterodyned with a reference signal taken from the sound generator. The resulting difference signal reproduces the surface wave pattern on the television screen, with the waves standing still as if their motion had been arrested by a stroboscope. Normally visible features of the substrate may also be reproduced to serve as background. In a further embodiment, the system is expanded to provide for recording of acoustic holograms.
Inventors
- 👤 Robert Adler
- 👤 Adrianus Korpel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:29
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/76; G; G01; G01H; G01H9/00; G01H9/002; H04N5/89
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
150 words
For use with a laser for generating a coherent light beam apparatus for detecting a characteristic of surface waves of predetermined acoustic wavelength on an object surface to be inspected, comprising: an optical system for focusing said light beam on said object surface to a spot smaller than said acoustic wavelength and for causing said light beam to obliquely scan said object surface transverse to said surface waves in accordance with a predetermined repetitive scanning pattern; output signal developing means including a photodetector and mask means having at least one edge in front of said photodetector for sensing variations in the lateral motion of light rays reflected obliquely from said object surface along a path which is inclined with respect to that of the incident scanning beam for developing an output signal; and optical means for imaging the exit pupil of said scanning system onto said output signal developing means.
Claim 2
Dependent Claim
150 words
For use with a laser for generating a coherent light beam apparatus for detecting a characteristic of surface waves of predetermined acoustic wavelength on an object surface to be inspected, comprising: an optical system for focusing said light beam on said object surface to a spot smaller than said acoustic wavelength and for causing said light beam to obliquely scan said object surface transverse to said surface waves in accordance with a predetermined repetitive scanning pattern; output signal developing means including a photodetector and mask means having at least one edge in front of said photodetector for sensing variations in the lateral motion of light rays reflected obliquely from said object surface along a path which is inclined with respect to that of the incident scanning beam for developing an output signal; and optical means for imaging the exit pupil of said scanning system onto said output signal developing means.
Claim 3
Dependent Claim
112 words
For use with a laser generating a coherent light beam, apparatus for detecting a characteristic of surface waves of predetermined acoustic wavelength on an object surface to be inspected, comprising: an optical system for focusing said light beam on said object surface to a spot smaller than said acoustic wavelength and for causing said light beam to scan said object surface in accordance with a predetermined repetitive scanning pattern; and means including photodetecting means and mask means having at least one edge in front of said photodetecting means for sensing variations in the lateral motion of light rays reflected from said surface for determining a characteristic of said waves on said surface.
Claim 4
Dependent Claim
112 words
For use with a laser generating a coherent light beam, apparatus for detecting a characteristic of surface waves of predetermined acoustic wavelength on an object surface to be inspected, comprising: an optical system for focusing said light beam on said object surface to a spot smaller than said acoustic wavelength and for causing said light beam to scan said object surface in accordance with a predetermined repetitive scanning pattern; and means including photodetecting means and mask means having at least one edge in front of said photodetecting means for sensing variations in the lateral motion of light rays reflected from said surface for determining a characteristic of said waves on said surface.
Claim 5
Dependent Claim
112 words
In combination: an ultrasonic transducer responsive to an applied electrical input signal for developing a field of acoustic vibrations in a predetermined surface plane; means including a flying spot laser scanner for scanning said surface plane with a collimated light beam; means responsive to variations in a predetermined characteristic of light reflected from said surface plane for developing an electrical output signal having a component dependent upon the acoustic vibrations in said surface plane; means for heterodyning said input and output signals; and means including an image display device coupled to said heterodyning means and synchronized to said flying spot laser scanner for generating a stationary visual display of said acoustic vibrations.
Claim 6
Dependent Claim
112 words
In combination: an ultrasonic transducer responsive to an applied electrical input signal for developing a field of acoustic vibrations in a predetermined surface plane; means including a flying spot laser scanner for scanning said surface plane with a collimated light beam; means responsive to variations in a predetermined characteristic of light reflected from said surface plane for developing an electrical output signal having a component dependent upon the acoustic vibrations in said surface plane; means for heterodyning said input and output signals; and means including an image display device coupled to said heterodyning means and synchronized to said flying spot laser scanner for generating a stationary visual display of said acoustic vibrations.
Claim 7
Dependent Claim
28 words
The combination of claim 3, in which said output signal developing means comprises a photodetector and an opaque element for detecting lateral motion in said reflected light beam.
References Cited (Backward Citations)
US3510664A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |