US3590145A
Expired / Lapsed
US
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Method and arrangement for eliminating persistency effects at low light levels in plumbicon tubes
Assignee: Robert Bosch Fernsehanlagen GmbH
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Filing: 1968-10-23
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Granted: 1971-06-29
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Expires: 1988-10-23
Abstract
Abstract An arrangement for eliminating visible persistencies in plumbicon tubes when used in conjunction with low light levels. An auxiliary current is produced in the photolayer of the tube for shifting the operating point for black from the origin of the diode characteristic of the tube. The shift is made to the linear portion of the tube characteristic. The signal portions arising from the auxiliary current are clipped from the output signal.
Inventors
- 👤 Friedrich Michels
- 👤 Horst Zschau
- 👤 Walter Michael
- 👤 Hans-Dieter Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:51
CPC Classifications
H; H01; H01J; H01J31/00; H01J31/08; H01J31/26; H01J31/28; H01J31/34; H01J31/38; H01J29/00; H01J29/02; H01J29/021; H04; H04N; H04N23/00; H04N23/10; H04N23/13; H04N23/16
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
69 words
A method for eliminating visible persistencies in plumbicon tubes for low light levels comprising the steps of producing an auxiliary current in the photolayer of said tube; shifting the operating point for black from the origin of the diode characteristic of the tube to the linear portion of said characteristic; transmitting the resulting signal from said tube; and clipping from said signal the portions arising from said auxiliary current.
Claim 2
Independent Claim
69 words
A method for eliminating visible persistencies in plumbicon tubes for low light levels comprising the steps of producing an auxiliary current in the photolayer of said tube; shifting the operating point for black from the origin of the diode characteristic of the tube to the linear portion of said characteristic; transmitting the resulting signal from said tube; and clipping from said signal the portions arising from said auxiliary current.
Claim 3
Dependent Claim
23 words
The method as defined in claim 1 including the step of illuminating the photocathode with constant uniform light for producing said auxiliary current.
Claim 4
Dependent Claim
23 words
The method as defined in claim 1 including the step of bombarding the photolayer with high velocity electrons for producing said auxiliary current.
Claim 5
Dependent Claim
17 words
The method as defined in claim 1 including the step of embedding raidoActive material in said photocathode.
Claim 6
Dependent Claim
24 words
The method as defined in claim 1 including the step of introducing intermediate layers in said photocathode for providing positively and negatively charged carriers.
Claim 7
Dependent Claim
20 words
The method as defined in claim 1 wherein said auxiliary current has a magnitude of between 5 and 20 nA.
Claim 8
Dependent Claim
82 words
An arrangement for eliminating visible persistencies in plumbicon tubes for low light levels, comprising, in combination, a plumbicon tube with photocathode; means for generating an auxiliary current in the photolayer of said cathode; means for shifting the operating point for black from the origin of the diode characteristic of the tube to the linear portion of said characteristics; means for transmitting the resulting signal from said tube; and clipping means for clipping from said signal the portion arising from said auxiliary current.
Claim 9
Dependent Claim
82 words
An arrangement for eliminating visible persistencies in plumbicon tubes for low light levels, comprising, in combination, a plumbicon tube with photocathode; means for generating an auxiliary current in the photolayer of said cathode; means for shifting the operating point for black from the origin of the diode characteristic of the tube to the linear portion of said characteristics; means for transmitting the resulting signal from said tube; and clipping means for clipping from said signal the portion arising from said auxiliary current.
Claim 10
Dependent Claim
53 words
The arrangement as defined in claim 7 including a camera objective lens functioning in conjunction with said plumbicon tube; a light dispersion member in close proximity to said photocathode and outside of the beam path of said camera objective lens; and a light source for illuminating with constant light said light dispersion member.
Claim 11
Dependent Claim
19 words
The arrangement as defined in claim 7 including a ring of fluorescent material in close proximity to the photocathode.
Claim 12
Dependent Claim
43 words
The arrangement as defined in claim 7 including picture tubes arranged for operating as a color camera, said picture tubes being associated with chrominance channels; and means connected to said picture tubes for generating an auxiliary current whereby said visible persistencies are eliminated.
Claim 13
Dependent Claim
32 words
The arrangement as defined in claim 10 wherein said means for producing an auxiliary current is connected to the red and blue color channels only, said color camera being a four-tube camera.
Claim 14
Dependent Claim
19 words
The arrangement as defined in claim 10 wherein said auxiliary current has a magnitude between 5 and 20 nA.
Claim 15
Dependent Claim
59 words
The arrangement as defined in claim 7 including a plurality of pickup tubes for different colors; an auxiliary light source for illuminating the photocathode with constant and uniform light for producing said auxiliary current, the illumination from said auxiliary light source being of the intensity whereby the auxiliary currents of the individual pickup tubes are all of identical magnitude.
Claim 16
Dependent Claim
24 words
The arrangement as defined in claim 13 wherein said auxiliary light source is arranged on the side of said photocathode facing the beam system.
Claim 17
Dependent Claim
35 words
The arrangement as defined in claim 13 wherein said auxiliary light source comprises a plurality of light sources with one light source associated with one picture pickup tube and independent from the other light sources.
Claim 18
Dependent Claim
39 words
The arrangement as defined in claim 12 including color-splitting means in said camera; and means for blending said auxiliary light from said auxiliary light source with corresponding spectral distribution into the picture light current before reaching the color-splitting means.
Claim 19
Dependent Claim
35 words
The arrangement as defined in claim 15 including test projector means, the mixing through said blending being over the same optical path as the path in which the picture of said test projector is introduced.
Claim 20
Dependent Claim
18 words
The arrangement as defined in claim 15 including means for regulating the spectral distribution of the auxiliary light.
Claim 21
Dependent Claim
32 words
The arrangement as defined in claim 15 wherein said auxiliary light source is a surface uniformly illuminated from different color light sources and imaged upon the photocathode of the picture pickup tube.
Claim 22
Dependent Claim
26 words
The arrangement as defined in claim 15 wherein said auxiliary light source is imaged in the diaphragm claim of the main objective lens of a camera.
Claim 23
Dependent Claim
25 words
The arrangement as defined in claim 15 wherein said auxiliary light source comprises a surface illuminated from different and independent lamps associated with color filters.
Claim 24
Dependent Claim
19 words
The arrangement as defined in claim 20 wherein said coLor filters comprises three color filters and a neutral filter.
Claim 25
Dependent Claim
37 words
The arrangement as defined in claim 21 wherein said color filters comprise first sectors of a circular disc; second sectors of opaque material between said first sectors; and diaphragm sectors over said opaque sectors and independently adjustable.
Claim 26
Dependent Claim
20 words
The arrangement as defined in claim 21 including light tubes for conducting light from said light source to said filters.
Claim 27
Dependent Claim
62 words
The arrangement as defined in claim 19 including optical fiber bundle means with a plurality of parts, one end of said bundle means illuminating said surface and the other end of said bundle means being in the path of light from differently colored and regulatable light sources so that the fibers of the individual bundle parts are statistically intermixed at one end.
Claim 28
Dependent Claim
23 words
The arrangement as defined in claim 19 wherein said surface is illuminated through a neutrally white surface with regulatable lamps of different color.
Claim 29
Dependent Claim
147 words
The arrangement as defined in claim 7 including a auxiliary light source for uniformly illuminating the photocathode with auxiliary illumination to generate said auxiliary current; a prism system of a color television camera for splitting the light beam into a plurality of channels; a first prism in said prism system to which the light from said auxiliary light source is applied, said auxiliary light source having means for regulating a spectral distribution; a second prism in the path of light from said first prism and arranged so that total light reflection prevails at the border surfaces between said prisms; entrance objective means against which the light from said prisms is deflected; and a partially-mirrored surface between said first prism and said entrance objective means, a portion of said auxiliary light from said auxiliary light source being returned from said partially-mirrored surface and distributed onto the pickup tubes.
Claim 30
Dependent Claim
25 words
The arrangement as defined in claim 27 wherein said first prism has a cut for admitting the auxiliary light from said auxiliary light source perpendicularly.
Claim 31
Dependent Claim
24 words
The arrangement as defined in claim 27 including a glass plate between said objective means and said first prism and containing said partially-mirrored surface.
Claim 32
Dependent Claim
20 words
The arrangement as defined in claim 29 wherein said partially-mirrored surface has a reflection coefficient between 5 and 10 percent.
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) | 1974-06-28 | 1974-12-28 | 1975-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-06-28 | 1978-12-28 | 1979-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-06-28 | 1982-12-28 | 1983-06-29 | $7700.00 | Window Closed / Lapsed |