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US2713129A - Television camera tube - Google Patents

Television camera tube Download PDF

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Publication number
US2713129A
US2713129A US255242A US25524251A US2713129A US 2713129 A US2713129 A US 2713129A US 255242 A US255242 A US 255242A US 25524251 A US25524251 A US 25524251A US 2713129 A US2713129 A US 2713129A
Authority
US
United States
Prior art keywords
tube
caesium
image
television camera
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US255242A
Other languages
English (en)
Inventor
Bruining Hajo
Lemmens Hendrikus Johannes
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hartford National Bank and Trust Co
Original Assignee
Hartford National Bank and Trust Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hartford National Bank and Trust Co filed Critical Hartford National Bank and Trust Co
Application granted granted Critical
Publication of US2713129A publication Critical patent/US2713129A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/26—Image pick-up tubes having an input of visible light and electric output
    • H01J31/28—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen
    • H01J31/30—Image pick-up tubes having an input of visible light and electric output with electron ray scanning the image screen having regulation of screen potential at anode potential, e.g. iconoscope
    • H01J31/32—Tubes with image amplification section, e.g. image-iconoscope, supericonoscope
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/88—Vessels; Containers; Vacuum locks provided with coatings on the walls thereof; Selection of materials for the coatings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/94—Selection of substances for gas fillings; Means for obtaining or maintaining the desired pressure within the tube, e.g. by gettering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J7/00—Details not provided for in the preceding groups and common to two or more basic types of discharge tubes or lamps
    • H01J7/14—Means for obtaining or maintaining the desired pressure within the vessel
    • H01J7/18—Means for absorbing or adsorbing gas, e.g. by gettering

Definitions

  • This invention relates to television camera tubes.
  • This photo-electric cathode is obtained by precipitating an alkaline metal on a conductive layer of a suitable metal, for example, silver or antimony.
  • Alkaline metal as a rule, caesium is introduced into the tube in the form of vapour and after the required amount of caesium to obtain the desired sensitiveness has been precipitated on the photo-cathode, the excess vapour is pumped out of the tube.
  • the excess caesium which cannot thus be removed from the tube may be rendered innocuous by a gas binder which, as a rule, is provided as a deposit on the tube wall.
  • the said measures are not suflicient for television transmission tubes, comprising an electrode system for producing a directional electron beam which is directed towards the image screen on the same side as the photo-cathode and arranged in a side-branch of the tube. It has been found that in these tubes the insulation of the parts supporting the electrodes deteriorates gradually and the life of the tubes is seriously reduced.
  • the object of the invention is to provide an improved television tube.
  • a television camera tube for producing electron-optical image magnification by photoemission and electrical acceleration of electrons comprising a scanning electrode system provided on the same side of the image electrode as the electron-optical projection means and arranged in a side-branch of the tube, is characterized in that a metal wall coating is applied as a conductive layer to the inner wall of the side-branch in order to avoid unequal voltage distribution thereon and at its end nearer the electrode system is of a metal which binds caesium vapour.
  • Use is preferably made of gold which may readily be applied in the form of a thin coating.
  • the caesium binding coating should not extend within the range of action of the magnetic deflection fields since due to the absorption of caesium, the electrical resistance of the coating and hence the damping which is produced by such a metal layer in an alternating magnetic field varies.
  • a camera tube 1 comprises a glass envelope of substantially circular section in the plane at right angles to the figure.
  • a narrow cylindrical part 2 of the tube merges into a wider part 3 which is closed by a substantially spherical bottom 4.
  • An image electrode 7 is secured by way of a support 5 to the bottom 4, to which support 5 is also secured a current supply wire 6. The construction of such an image electrode is known and will not be further described.
  • the narrow cylindrical part 2 of the tube 1 is closed by a fiat plate 8.
  • the plate 8 is coated with a thin, transparent, conductive layer 9, for example, of iridium.
  • a thin metal layer 10, for example, of silver or antimony is applied by evaporation to the layer 9.
  • the layer 10 is activated by introducing oxygen and caesium vapour into the tube. When the required degree of photosensitiveness is reached, the excess caesium vapour is exhausted in known manner.
  • a deposit 11 of one of the known caesium-binding substances may be applied to the wall of the tube.
  • Electrons emitted by the photo-cathode may be concentrated on the image electrode 7 by a magnetic field produced by a coil 12 and produce a potential image which corresponds with the electron image emitted by the photo-cathode.
  • an electrode system 13 arranged on the same side of the electrode 7 as the photo-cathode and directed towards the image electrode is housed in a side-branch 14 secured to the tube wall and projecting sideways therefrom.
  • the electron beam produced by this system is focussed by means of a magnetic field produced by a coil 15, the required deflection of the electron beam for scanning the image electrode 7 being produced with the use of a coil system 16.
  • the inner surface of the side-branch 14 is coated with a conductive layer 17 in order to neutralize wall charges.
  • This wall coating which may, for example, be of aluminium, may extend into the interior of the tube and thus operate at the same time as a collecting electrode for secondary electrons produced when electrons strike the image electrode 7.
  • the conductive coating 17 is provided with a rim 18 which is a layer of a metal, preferably gold, suitable for binding caesium vapour. In this manner, inadmissible increase in electrical conductivity of those surfaces which are used for the insulated arrangement of the electrodes of the electrode system 13, is counteracted.
  • a television camera tube for producing electronoptical image magnification comprising a vitreous envelope, including a side-branch, a caesium-activated photo-emissive layer disposed on the inner surface of said envelope at one end thereof, an image electrode disposed within said envelope at the other end thereof, electronoptical means for projecting an electron image produced by said photo-emissive layer onto said image electrode, a scanning electrode system disposed on the same side of the image electrode as the photoemissive layer and within the side-branch of the envelope and positioned to scan said image electrode with an electron beam, and a metal conductive coating on the inner surface of the wall of said side-branch of the envelope containing said scanning electrode system to prevent unequal potential distributionsthereon, the portion of said conductive coating adjacent said electrode system being constituted by a metal capable of binding caesium vapour.

Landscapes

  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US255242A 1950-11-13 1951-11-07 Television camera tube Expired - Lifetime US2713129A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL295267X 1950-11-13

Publications (1)

Publication Number Publication Date
US2713129A true US2713129A (en) 1955-07-12

Family

ID=19782948

Family Applications (1)

Application Number Title Priority Date Filing Date
US255242A Expired - Lifetime US2713129A (en) 1950-11-13 1951-11-07 Television camera tube

Country Status (7)

Country Link
US (1) US2713129A (de)
BE (1) BE507061A (de)
CH (1) CH295267A (de)
DE (1) DE954071C (de)
FR (1) FR1045054A (de)
GB (1) GB693678A (de)
NL (2) NL157248B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329853A (en) * 1965-06-16 1967-07-04 Rca Corp Image orthicon with cesium getter adjacent electron multiplier

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1831314A (en) * 1930-06-14 1931-11-10 G M Lab Inc Photoelectric tube
US1936419A (en) * 1930-06-03 1933-11-21 Gen Electric Photo-electric tube
US2149455A (en) * 1934-10-24 1939-03-07 Emi Ltd Television transmitting apparatus
US2189988A (en) * 1937-09-28 1940-02-13 Rca Corp Photoelectric device
US2273639A (en) * 1938-10-25 1942-02-17 Rca Corp Selectivity control circuit

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB567650A (en) * 1943-03-19 1945-02-26 Cinema Television Ltd Improvements in or relating to alloys

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1936419A (en) * 1930-06-03 1933-11-21 Gen Electric Photo-electric tube
US1831314A (en) * 1930-06-14 1931-11-10 G M Lab Inc Photoelectric tube
US2149455A (en) * 1934-10-24 1939-03-07 Emi Ltd Television transmitting apparatus
US2189988A (en) * 1937-09-28 1940-02-13 Rca Corp Photoelectric device
US2273639A (en) * 1938-10-25 1942-02-17 Rca Corp Selectivity control circuit

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3329853A (en) * 1965-06-16 1967-07-04 Rca Corp Image orthicon with cesium getter adjacent electron multiplier

Also Published As

Publication number Publication date
GB693678A (en) 1953-07-01
NL157248B (nl)
BE507061A (de)
CH295267A (de) 1953-12-15
DE954071C (de) 1956-12-13
FR1045054A (fr) 1953-11-24
NL79449C (de)

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