US3720782A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Lensless flying-spot scanner for generating color signals
Assignee: AT&T Inc
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Filing: 1971-12-20
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Granted: 1973-03-13
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Expires: 1991-12-20
Abstract
Abstract A color transparency is placed on the face of a flying-spot scanning cathode ray tube whose light spot is raster scanned in a conventional fashion. Three juxtaposed photomultipliers are placed a given distance in front of the cathode ray tube to collect the light transmitted by the transparency. Three primary color signals are selected by the use of appropriate color filters which cover the respective faces of the three photomultipliers. The image parallax resulting from this arrangement is compensated electrically by delay lines at the photomultiplier outputs.
Inventors
- 👤 W Kaminski
- 👤 H Kogelnik
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 01:24
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/222; H04N5/257
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
136 words
In a color camera system, a flying-spot scanner including a cathode ray tube whose light spot is raster scanned over the face of the tube, a color transparency positioned at the face of said tube, three photodetectors positioned side by side a selected distance in front of said tube to collect the light transmitted by the transparency as the same is scanned by the scanning light spot, said photodetectors being mounted on a plane parallel to the horizontal scan lines of said raster scan, three color selection filters respectively covering the faces of the photodetectors and serving to tune the spectral response of the latter to a desired trichromatic taking characteristic, and delay means connected to the output of each photodetector for delaying the photodetector output signals by selected amounts to achieve a time coincidence therebetween.
Claim 2
Dependent Claim
136 words
In a color camera system, a flying-spot scanner including a cathode ray tube whose light spot is raster scanned over the face of the tube, a color transparency positioned at the face of said tube, three photodetectors positioned side by side a selected distance in front of said tube to collect the light transmitted by the transparency as the same is scanned by the scanning light spot, said photodetectors being mounted on a plane parallel to the horizontal scan lines of said raster scan, three color selection filters respectively covering the faces of the photodetectors and serving to tune the spectral response of the latter to a desired trichromatic taking characteristic, and delay means connected to the output of each photodetector for delaying the photodetector output signals by selected amounts to achieve a time coincidence therebetween.
Claim 3
Dependent Claim
136 words
In a color camera system, a flying-spot scanner including a cathode ray tube whose light spot is raster scanned over the face of the tube, a color transparency positioned at the face of said tube, three photodetectors positioned side by side a selected distance in front of said tube to collect the light transmitted by the transparency as the same is scanned by the scanning light spot, said photodetectors being mounted on a plane parallel to the horizontal scan lines of said raster scan, three color selection filters respectively covering the faces of the photodetectors and serving to tune the spectral response of the latter to a desired trichromatic taking characteristic, and delay means connected to the output of each photodetector for delaying the photodetector output signals by selected amounts to achieve a time coincidence therebetween.
Claim 4
Dependent Claim
136 words
In a color camera system, a flying-spot scanner including a cathode ray tube whose light spot is raster scanned over the face of the tube, a color transparency positioned at the face of said tube, three photodetectors positioned side by side a selected distance in front of said tube to collect the light transmitted by the transparency as the same is scanned by the scanning light spot, said photodetectors being mounted on a plane parallel to the horizontal scan lines of said raster scan, three color selection filters respectively covering the faces of the photodetectors and serving to tune the spectral response of the latter to a desired trichromatic taking characteristic, and delay means connected to the output of each photodetector for delaying the photodetector output signals by selected amounts to achieve a time coincidence therebetween.
Claim 5
Dependent Claim
65 words
A color camera system as defined in claim 1 wherein said delay means comprises a delay line of fixed delay in each photodetector output path, the delay line in the path of the intermediately positioned photodetector providing a delay of Delta t seconds, and the delay lines in the paths of the other photodetectors providing respective delays of Delta t + or -Delta t seconds.
Claim 6
Dependent Claim
76 words
A color camera system in accordance with claim 2 wherein the delay value Delta t is given by the equation Delta t d( Delta z)/Dnv where d is the thickness of the glass faceplate of the cathode ray tube, Delta z is the separation between adjacent photodetectors, D is distance separating the cathode ray tube and the photodetectors, n is the index of refraction of the faceplate glass, and v is the horizontal spot scan velocity.
Claim 7
Dependent Claim
23 words
A color camera system as defined in claim 3 wherein the trichromatic taking characteristic comprises the primary colors of red, green and blue.
Claim 8
Dependent Claim
50 words
A color camera system as defined in claim 1 wherein said delay means comprises a delay line of variable delay in the output paths of at least two of said photodetectors, said delay being varied in each case as a function of the horizontal scan time of the scanning spot.
Claim 9
Dependent Claim
99 words
A color camera system as defined in claim 5 wherein the relative delays provided between the output signals of adjacent photomultipliers are exactly determined by the implicit equation1 + (d/y-x)2 n2 + n2 (D/z-y)2 where x represents the instantaneous position of the scanning light spot, y represents the position of a picture element under illumination, z represents the position of a given photomultiplier, d is the thickness of the glass faceplate of the cathode ray tube, n is the index of refraction of the faceplate glass, and D is the distance separating the cathode ray tube and the photodetectors.
References Cited (Backward Citations)
US3472948A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |