US3657550A
Expired / Lapsed
US
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Apparatus for measuring the spatial response of optical systems
Assignee: AT&T Inc
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Filing: 1970-04-07
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Granted: 1972-04-18
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Expires: 1990-04-07
Abstract
Abstract To measure the spatial response characteristics of optical systems, control circuitry is provided to electrically generate a predetermined one-dimensional spatial waveform (e.g., sinusoidal) on the display screen of a cathode ray tube. The optical system to be tested (e.g., a television system) is placed between the spatial waveform display and a suitable detector which comprises a mask having a narrow slit followed by a photomultiplier. The output of the latter is then displayed on an oscilloscope, or measured in some other known fashion. A linear light modulation is achieved for the spatial waveform display by gating a linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses. Appropriate waveforms can be selected to evaluate the spatial frequency response, transient response, linearity, or steady state response of the optical system under test.
Inventors
- 👤 Earl Franklin Brown
- 👤 William Kaminski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:17
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0292
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
145 words
Apparatus for measuring the spatial response characteristics of an optical system comprising a cathode ray tube, means for electrically generating on the display screen of said cathode ray tube a predetermined spatial waveform whose intensity varies in one-dimension and is linearly related to the signal electrically generating the same, said generating means including means for varying the periodicity of said spatial waveform, a mask having a sMall aperture, the optical system under test being disposed between said mask and cathode ray tube and serving to relay an image of a segment of said spatial waveform to the aperture in said mask, a photo-detector disposed behind said mask, means coupled to the output of said photo-detector for providing for the measurement of the light intensity detected by said photodetector, and means for causing a slow scan of the spatial waveform image with respect to said aperture.
Claim 2
Dependent Claim
145 words
Apparatus for measuring the spatial response characteristics of an optical system comprising a cathode ray tube, means for electrically generating on the display screen of said cathode ray tube a predetermined spatial waveform whose intensity varies in one-dimension and is linearly related to the signal electrically generating the same, said generating means including means for varying the periodicity of said spatial waveform, a mask having a sMall aperture, the optical system under test being disposed between said mask and cathode ray tube and serving to relay an image of a segment of said spatial waveform to the aperture in said mask, a photo-detector disposed behind said mask, means coupled to the output of said photo-detector for providing for the measurement of the light intensity detected by said photodetector, and means for causing a slow scan of the spatial waveform image with respect to said aperture.
Claim 3
Dependent Claim
149 words
Apparatus for measuring the spatial response characteristics of an optical system comprising a cathode ray tube, means for electrically generating a one-dimensional spatial waveform on the display screen of said cathode ray tube with the luminosity of said cathode ray display bearing a linear proportional relationship to the signal electrically generating the same, said generating means including means for varying the periodicity of said spatial waveform, an opaque mask having a small aperture therein, the optical system under test being disposed between said mask and cathode ray tube and serving to image a small segment of the spatial waveform display upon said aperture, a photo-detector disposed behind said opaque mask, means coupled to the output of said photo-detector for providing for the measurement of the spatial response of the optical system under test, and means for causing a slow drift of the one-dimensional spatial waveform relative to said aperture.
Claim 4
Dependent Claim
149 words
Apparatus for measuring the spatial response characteristics of an optical system comprising a cathode ray tube, means for electrically generating a one-dimensional spatial waveform on the display screen of said cathode ray tube with the luminosity of said cathode ray display bearing a linear proportional relationship to the signal electrically generating the same, said generating means including means for varying the periodicity of said spatial waveform, an opaque mask having a small aperture therein, the optical system under test being disposed between said mask and cathode ray tube and serving to image a small segment of the spatial waveform display upon said aperture, a photo-detector disposed behind said opaque mask, means coupled to the output of said photo-detector for providing for the measurement of the spatial response of the optical system under test, and means for causing a slow drift of the one-dimensional spatial waveform relative to said aperture.
Claim 5
Dependent Claim
23 words
Apparatus as defined in claim 2 wherein said electrical generating means serves to generate a one-dimensional sinusoidal spatial waveform of n sine waves.
Claim 6
Dependent Claim
14 words
Apparatus as defined in claim 3 wherein said sinusoidal spatial waveform is frequency modulated.
Claim 7
Dependent Claim
22 words
Apparatus as defined in claim 2 wherein said electrical generating means serves to generate a spatial waveform comprising n triangular spatial waves.
Claim 8
Dependent Claim
22 words
Apparatus as defined in claim 2 wherein said electrical generating means serves to generate a spatial waveform comprising n spatial square waves.
Claim 9
Dependent Claim
180 words
Apparatus for measuring the spatial response of optical systems comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a predetermined one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for varying the duty cycle of the gating pulses in a selected manner, an opaque mask having a narrow slit therein, the optical system under test being disposed between said mask and the cathode ray tube and serving to relay an image of a small segment of the spatial waveform display to said slit, a photo-detector disposed behind said opaque mask, means coupled to the output of said photo-detector for providing for the measurement of the light intensity detected by said photo-detector, and means for causing a slow drift of the one-dimensional spatial waveform relative to the slit in said mask.
Claim 10
Dependent Claim
180 words
Apparatus for measuring the spatial response of optical systems comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a predetermined one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for varying the duty cycle of the gating pulses in a selected manner, an opaque mask having a narrow slit therein, the optical system under test being disposed between said mask and the cathode ray tube and serving to relay an image of a small segment of the spatial waveform display to said slit, a photo-detector disposed behind said opaque mask, means coupled to the output of said photo-detector for providing for the measurement of the light intensity detected by said photo-detector, and means for causing a slow drift of the one-dimensional spatial waveform relative to the slit in said mask.
Claim 11
Dependent Claim
31 words
Apparatus as defined in claim 7 wherein the duty cycle of said gating pulses is varied sinusoidally so as to generate a one-dimensional sinusoidal spatial waveform of n spatial sine waves.
Claim 12
Dependent Claim
33 words
Apparatus as defined in claim 8 wherein the sinusoidal variation of said duty cycle is carried out at a linearly varying rate so as to provide a linearly varying sinusoidal spatial waveform display.
Claim 13
Dependent Claim
32 words
Apparatus as defined in claim 7 wherein the duty cycle of the gating pulses is varied in a manner such as to achieve a spatial waveform display of n triangular spatial waves.
Claim 14
Dependent Claim
32 words
Apparatus as defined in claim 7 wherein the duty cycle of the gating pulses is varied in a manner such as to achieve a spatial waveform display of n spatial square waves.
Claim 15
Dependent Claim
46 words
Apparatus as defined in claim 7 wherein the electron beam scanning means is operated at a non-synchronous offset frequency with respect to a sub-multiple of the operating frequency of the duty cycle varying means so as to effect a slow drift in the spatial waveform display.
Claim 16
Dependent Claim
179 words
Apparatus for measuring the spatial frequency response of an optical system comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for sinusoidally varying the duty cycle of said gating pulses, an opaque mask having a narrow slit therein, the optical system under test being disposed between said mask and the cathode ray tube and serving to relay an image of a finite segment of the spatial waveform display to said slit, a photo-detector disposed behind said opaque mask, oscilloscope means connected to the output of said photo-detector for providing a visual indication of the instantaneous light intensity detected by said photo-detector, and means for causing a slow drift in the one-dimensional sinusoidal spatial waveform displayed on said display screen.
Claim 17
Dependent Claim
179 words
Apparatus for measuring the spatial frequency response of an optical system comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for sinusoidally varying the duty cycle of said gating pulses, an opaque mask having a narrow slit therein, the optical system under test being disposed between said mask and the cathode ray tube and serving to relay an image of a finite segment of the spatial waveform display to said slit, a photo-detector disposed behind said opaque mask, oscilloscope means connected to the output of said photo-detector for providing a visual indication of the instantaneous light intensity detected by said photo-detector, and means for causing a slow drift in the one-dimensional sinusoidal spatial waveform displayed on said display screen.
Claim 18
Dependent Claim
35 words
Apparatus as defined in claim 13 wherein the sinusoidal variation of said duty cycle is carried out in a linear frequency modulated fashion so as to provide a linear frequency modulated sinusoidal spatial waveform display.
Claim 19
Dependent Claim
118 words
A spatial waveform display for use in making spatial response measurements off optical systems comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a predetermined one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for varying the duty cycle of the gating pulses in a selected manner, and means for causing a slow drift in the spatial waveform generated on the display screen of said cathode ray tube.
Claim 20
Dependent Claim
118 words
A spatial waveform display for use in making spatial response measurements off optical systems comprising a cathode ray tube, means for linearly scanning the electron beam of said cathode ray tube in one given direction, means for gating the linearly scanned electron beam with constant amplitude, constant duration, variable duty cycle pulses so as to generate on the display screen of said cathode ray tube a predetermined one-dimensional spatial waveform whose luminosity is linearly related to the duty cycle of the gating pulses, means for varying the duty cycle of the gating pulses in a selected manner, and means for causing a slow drift in the spatial waveform generated on the display screen of said cathode ray tube.
Claim 21
Dependent Claim
35 words
Apparatus as defined in claim 15 wherein the duty cycle of said gating pulses is varied sinusoidally so as to generate a one-dimensional sinusoidal spatial waveform of n spatial sine waves on said display screen.
Claim 22
Dependent Claim
32 words
Apparatus as defined in claim 16 including means for linearly varying the frequency of the sinusoidal variations of said duty cycle so as to provide a linearly varying sinusoidal spatial waveform display.
Claim 23
Dependent Claim
32 words
Apparatus as defined in claim 15 wherein the duty cycle of the gating pulses is varied in a manner such as to achieve a spatial waveform display of n triangular spatial waves.
Claim 24
Dependent Claim
32 words
Apparatus as defined in claim 15 wherein the duty cycle of the gating pulses is varied in a manner such as to achieve a spatial waveform display of n spatial square waves.
Claim 25
Dependent Claim
48 words
Apparatus as defined in claim 15 wherein the electron beam scanning means is operated at a non-synchronous frequency which is offset with respect to a sub-multiple of the operating frequency of the duty cycle varying means so as to effect the slow drift in the spatial waveform display.
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) | 1975-04-18 | 1975-10-18 | 1976-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-18 | 1979-10-18 | 1980-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-18 | 1983-10-18 | 1984-04-18 | $7700.00 | Window Closed / Lapsed |