Patent US4547694A successfully refreshed from Google Patents.
US4547694A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low-loss cathode for a television camera tube
Assignee: US Philips Corp
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Filing: 1982-11-12
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Granted: 1985-10-15
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Expires: 2002-11-12
Abstract
Abstract By providing the cathode, in a diode electron gun in a television camera tube, with an at least 40 μm high collar extending in the direction of the anode, the anode current is considerably reduced.
Inventors
- 👤 Erich E. Himmelbauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:49
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/02; H01J29/04; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/28; H01J29/46; H01J29/48; H01J29/485; H01J9/00; H01J9/02; H01J9/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
169 words
A television camera tube comprising: an evacuated envelope having an axis and first and second opposite ends; a photosensitive target at the first end of the envelope; a cathode arranged toward the second end of the envelope opposite the first end, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; an anode arranged between the cathode and the target, said anode having a central aperture around the axis; and a focusing lens arranged between the anode and the target for focusing an electron beam from the cathode and anode onto the target; characterized in that: the camera tube further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis at least 40 microns in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
Claim 2
Dependent Claim
169 words
A television camera tube comprising: an evacuated envelope having an axis and first and second opposite ends; a photosensitive target at the first end of the envelope; a cathode arranged toward the second end of the envelope opposite the first end, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; an anode arranged between the cathode and the target, said anode having a central aperture around the axis; and a focusing lens arranged between the anode and the target for focusing an electron beam from the cathode and anode onto the target; characterized in that: the camera tube further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis at least 40 microns in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
Claim 3
Dependent Claim
17 words
A television camera tube as claimed in claim 1, characterized in that the collar is a cylinder.
Claim 4
Dependent Claim
18 words
A television camera tube as claimed in claim 2, characterized in that the collar is a circular cylinder.
Claim 5
Dependent Claim
17 words
A television camera tube as claimed in claim 1, characterized in that the collar extends 100 microns.
Claim 6
Dependent Claim
17 words
A television camera tube as claimed in claim 1, characterized in that the collar extends 150 microns.
Claim 7
Dependent Claim
35 words
A television camera tube as claimed in claim 1, characterized in that: the cathode is a dispenser cathode with a holder which envelops a porous emissive body; and the collar is integral with the holder.
Claim 8
Dependent Claim
32 words
A television camera tube as claimed in claim 10, characterized in that the pores in the portion of the emissive surface adjacent to the collar are sealed by a high energy beam.
Claim 9
Dependent Claim
117 words
A diode electron gun comprising: a cathode arranged on an axis, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; and an anode arranged on the axis spaced from the cathode, said anode having a central aperture around the axis; characterized in that: the electron gun further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis at least 40 microns in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
Claim 10
Dependent Claim
117 words
A diode electron gun comprising: a cathode arranged on an axis, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; and an anode arranged on the axis spaced from the cathode, said anode having a central aperture around the axis; characterized in that: the electron gun further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis at least 40 microns in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
Claim 11
Dependent Claim
17 words
A diode electron gun as claimed in claim 8, characterized in that the collar extends 100 microns.
Claim 12
Dependent Claim
17 words
A diode electron gun as claimed in claim 8, characterized in that the collar extends 150 microns.
Claim 13
Dependent Claim
112 words
An electron gun comprising: a cathode arranged on an axis, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; and an anode arranged on the axis spaced from the cathode, said anode having a central aperture around the axis; characterized in that: the electron gun further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
Claim 14
Dependent Claim
112 words
An electron gun comprising: a cathode arranged on an axis, said cathode having an emissive surface centered on and extending substantially perpendicular to the axis; and an anode arranged on the axis spaced from the cathode, said anode having a central aperture around the axis; characterized in that: the electron gun further comprises an electrically conductive collar arranged around the emissive surface of the cathode, said collar extending from the emissive surface substantially parallel to the axis in the direction of the anode; and the emissive surface of the cathode is porous, and the emissive surface has a portion adjacent to the collar which is less porous than a central portion thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |