US2198327A - Mosaic electrode structure - Google Patents

Mosaic electrode structure Download PDF

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Publication number
US2198327A
US2198327A US193129A US19312938A US2198327A US 2198327 A US2198327 A US 2198327A US 193129 A US193129 A US 193129A US 19312938 A US19312938 A US 19312938A US 2198327 A US2198327 A US 2198327A
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US
United States
Prior art keywords
particles
film
sheet
metal
mosaic
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
US193129A
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English (en)
Inventor
Bandringa Menze
Teves Marten Cornelis
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.)
RCA Corp
Original Assignee
RCA Corp
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 RCA Corp filed Critical RCA Corp
Application granted granted Critical
Publication of US2198327A publication Critical patent/US2198327A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/41—Charge-storage screens using secondary emission, e.g. for 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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/43—Charge-storage screens using photo-emissive mosaic, e.g. for orthicon, for iconoscope
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/913—Material designed to be responsive to temperature, light, moisture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24355—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
    • Y10T428/24364—Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.] with transparent or protective coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24942—Structurally defined web or sheet [e.g., overall dimension, etc.] including components having same physical characteristic in differing degree
    • Y10T428/2495—Thickness [relative or absolute]
    • Y10T428/24967—Absolute thicknesses specified
    • Y10T428/24975—No layer or component greater than 5 mils thick

Definitions

  • the mosaic electrode of television transmitting tubes of the type known as the iconoscope frequently comprises a thin sheet of insulating material such as a sheet of mica which constitutes the dielectric of a multiple condenser.
  • the mica sheet is coated on one side with a conductive layer, such as a sheetof metal, which serves as a common electrode of the condenser. .On the other side of the mica sheet there are, distributed over the entire surface, mutually separated con.
  • ductive particles which are electrically insulated from each other and which are coated or sensitized with .a-substance capable of emitting photoelectrons or secondary electrons.
  • sensitized particles constitute the complementary electrodes of the multiple condenser and are referred to hereinafter as sensitive particlesfif They may jointly cover, about one quarter toone'half of the surface of the dielectric. Thus, the voids left between the sensitive parts occupy about one half to three quarters of the surface.
  • the sensitive particles When an optical image is projected on the mosaic electrode the sensitive particles acquire electrostatic charges which vary in magnitude in accordance with the incident light, but when the electrode is scanned bythe cathode ray beam to neutralize the charges, it is found that electrons find their way through the voids between the sensitive particles and dislodge from the exposed dielectric secondary electrons which influence the electrostatic charges on the sensitiveparticles in an unfavorable way thus introducing spurious slgnalswhich interfere with the desired operation of the device.
  • An object of our invention is to provide an improved mosaic electrode for use in television transmitting tubes wherein secondary electron emission from the exposed dielectric between the sensitive particles is suppressed
  • Another object of our invention is to provide a mosaic electrode which is uniformly responsive to the influence of light over its active surface.
  • the sheet of insulating material of dielectric has-applied to it, before the formation of the sensitive particles, a braking layer which is formed from metal only slightly capable of emitting secondary electrons and which prevents the electrons of the cathode ray beam which enter the voids between the sensitive particles from dislo ging secondary electrons from the dielectric.
  • our new and improved mosaic electrode comprises a foundation sheetof insulating material such as the sheet of mica ill with a uniform coating or. film of an electrical conductor such as the metal film ii on one side to serve as the signal plate ofthe electrode,'and a multiplicity of individually separated photosensitive particles I? supported from the opposite side of the sheet of mica ill by an intermediate film or layer of metal is which will hereinafter be termed the braking layer.
  • the sensitive particles l2 are mutually, insulated one from the other except for the very-slight electrical conduction which may take place through the braking layer.
  • the braking layer must be thick enough to obtain the desired advantages, and must also be of such a kind that it does not electrically conmeet the sensitive particles or at least connects them by a very high resistance, so that the conductivity in the layer does not exceed that which is admissible for the operation oi the tube in which the mosaic is used.
  • a layer of sufficiently high resistance maybe obtained by male ing the layer very thin.
  • the resistance of the braking layer over a width oi looms. is preferably at least 10 ohms per cm, of length, as such a layer, has negligible electrical conductivity at the voltages applied to the film during operation.
  • any oxide film that may be present should, preferably, be less than 20 atoms thick.
  • Suitable metals for the braking layer are, for example, aluminum, platinum, gold, and chromium.
  • Aluminum layers have a particular advantage in'that they do not have appreciable conductivity even when of comparatively large mean-thickness, for example, a mean thickness of approximately 100 atoms. The thicker the braking layer, the greater is the protection against penetration of primary electrons into the insulating material.
  • the coating of the mica with athin film of metal which serves as the braking layer may be done most conveniently by mounting the mica sheet within a sealed envelope together with a tungsten filament which may be heated to incandescence and which has been coated with the aluminum or other metal with whichthe mica sheet is to be coated.
  • the envelope is then evacuated and the filament heated to flash of? enough of the metal with which it is coated to produce the desired film on the mica sheet.
  • good results have been obtained with a a" x sheet of mica by placing the filament approximately 10 inchesfrom the surface of the mica.
  • aluminum When using aluminum as a metal with which to coat the mica, about 42 mgs. of aluminum is vaporized from. the filament to give a deposit of 0.67 mg.
  • the mica sheet which corresponds to a layer 'of aluminum approximately 100 atoms thick.
  • the exact quantity of aluminum to be evaporated may be applied to the tungsten filament which is then heated to a temperature of 1,000 to 1200 C. for a period of approximately 10 minutes to insure vaporization of the entire amount.
  • the above data are calculated from the atomic weight oialuminum and the crystalline structure of the metal as determined by X-ray analysis.
  • a mosaic electrode for a television transmitting tube comprising a sheet of insulating material, a coating of electrically conductive material on the surface of one side of said sheet of insulating. material to serve as a signal plate for the electrode, a film having, high electrical re-,.
  • said film of metal having negligible electrical conductivity, and a multiplicity of mutually separated photosensitive 'metal particles'on said film coextensive with said coating of electrically conductive material, the

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US193129A 1937-03-05 1938-02-28 Mosaic electrode structure Expired - Lifetime US2198327A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE496018X 1937-03-05

Publications (1)

Publication Number Publication Date
US2198327A true US2198327A (en) 1940-04-23

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ID=6544977

Family Applications (1)

Application Number Title Priority Date Filing Date
US193129A Expired - Lifetime US2198327A (en) 1937-03-05 1938-02-28 Mosaic electrode structure

Country Status (4)

Country Link
US (1) US2198327A (en(2012))
FR (1) FR834864A (en(2012))
GB (1) GB496018A (en(2012))
NL (1) NL52244C (en(2012))

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2476590A (en) * 1943-07-03 1949-07-19 Westinghouse Electric Corp Cathode coating
US2745772A (en) * 1950-02-23 1956-05-15 Emi Ltd Manufacture of mosaic screens such as are utilized in television transmission tubes
US2874101A (en) * 1952-09-17 1959-02-17 Farnsworth Res Corp Method of making double-sided mosaic
US2882413A (en) * 1953-12-04 1959-04-14 Vingerhoets Antonius Wilhelmus Luminescent screen
US3070721A (en) * 1959-10-19 1962-12-25 Eitel Mccullough Inc Electron tube

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2476590A (en) * 1943-07-03 1949-07-19 Westinghouse Electric Corp Cathode coating
US2745772A (en) * 1950-02-23 1956-05-15 Emi Ltd Manufacture of mosaic screens such as are utilized in television transmission tubes
US2874101A (en) * 1952-09-17 1959-02-17 Farnsworth Res Corp Method of making double-sided mosaic
US2882413A (en) * 1953-12-04 1959-04-14 Vingerhoets Antonius Wilhelmus Luminescent screen
US3070721A (en) * 1959-10-19 1962-12-25 Eitel Mccullough Inc Electron tube

Also Published As

Publication number Publication date
NL52244C (en(2012))
FR834864A (fr) 1938-12-05
GB496018A (en) 1938-11-23

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