US3892994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vidicon camera tube with internal light source for setting dark current level
Assignee: Teledyne UK Ltd
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Filing: 1974-05-13
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Granted: 1975-07-01
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Expires: 1994-05-13
Abstract
Abstract A camera tube, in particular a vidicon tube, is provided with a lamp arranged to provide illumination of the target electrode to reduce the effect known as ''''build-up lag.'''' Undesirable internal reflections are reduced by the provision of light absorbing material in the vicinity of the window of the tube. The internal reflections would otherwise result in unacceptable variations in the intensity of illumination in different regions of the target electrode.
Inventors
- 👤 Hans Scholz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:52
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/86; H01J29/89; H01J31/00; H01J31/08; H01J31/26; H01J31/28; H01J31/34; H01J31/38
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
169 words
A camera tube of the vidicon type comprising an envelope, closed at one end to form the face of the tube, which includes a sidewall, the face of the tube, and a portion joining said sidewall and said face; a light source within saiD envelope for emitting light which is conducted via said sidewall and said portion to said face; a target disposed between said light source and said face and sufficiently close to said face so that some of the light is conducted into said face to illuminate the target and cause a small quiescent current to flow therein while some of the light is reflected at said portion of the envelope tending to impinge directly on the target and produce non-uniform illumination thereof; and suppression means provided at said portion for reducing the internal reflection which produces direct impingement of light on said target so as to result in a more uniform illumination of the target and to cause a more uniform quiescent current to flow therein.
Claim 2
Dependent Claim
169 words
A camera tube of the vidicon type comprising an envelope, closed at one end to form the face of the tube, which includes a sidewall, the face of the tube, and a portion joining said sidewall and said face; a light source within saiD envelope for emitting light which is conducted via said sidewall and said portion to said face; a target disposed between said light source and said face and sufficiently close to said face so that some of the light is conducted into said face to illuminate the target and cause a small quiescent current to flow therein while some of the light is reflected at said portion of the envelope tending to impinge directly on the target and produce non-uniform illumination thereof; and suppression means provided at said portion for reducing the internal reflection which produces direct impingement of light on said target so as to result in a more uniform illumination of the target and to cause a more uniform quiescent current to flow therein.
Claim 3
Dependent Claim
33 words
A tube as claimed in claim 1 and wherein said last mentioned means comprises light absorbent material provided on the outside of said portion of the tube envelope and framing said face thereof.
Claim 4
Dependent Claim
53 words
A tube as claimed in claim 2 including a target mesh electrode between said target and said light source and wherein the light absorbing material extends from the edge of the face of the tube inwardly towards and ends approximately at the projected outer boundary of the target mesh electrode of the tube.
Claim 5
Dependent Claim
17 words
A tube as claimed in claim 2 and wherein the light absorbing material is matt black cellulose.
Claim 6
Dependent Claim
73 words
A tube as claimed in claim 1 including a base located at that end of the tube opposite to the face, electrical connection means passing through said base, and a cathode heater connected to said electrical connection means, and wherein the light source is located on the axis of the tube and comprises a single filament positioned in the region between the cathode heater of the tube and the base of the tube.
Claim 7
Dependent Claim
30 words
A tube as claimed in claim 5 and wherein the light source is electrically connected to and supported by the electrical connector means so as to operate in parallel therewith.
Claim 8
Dependent Claim
27 words
A tube as claimed in claim 5 and wherein said light source is a filament similar to the filament of the cathode heater of the camera tube.
Claim 9
Dependent Claim
42 words
A tube as claimed in claim 2 and wherein light absorbent material is provided on the tube envelope in the region of the light source, so as to absorb a portion of the light from the source entering the envelope side walls.
Claim 10
Dependent Claim
39 words
A tube as claimed in claim 1 wherein said portion is of such dimensions as to cause an optimum amount of light to be conducted around said portion, past said suppression means and into said face of the tube.
References Cited (Backward Citations)
US3751703A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |