US3250942A - Cathode ray tube with improved deflection magnifying screen - Google Patents

Cathode ray tube with improved deflection magnifying screen Download PDF

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Publication number
US3250942A
US3250942A US126981A US12698161A US3250942A US 3250942 A US3250942 A US 3250942A US 126981 A US126981 A US 126981A US 12698161 A US12698161 A US 12698161A US 3250942 A US3250942 A US 3250942A
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US
United States
Prior art keywords
ray tube
mesh
screen
cathode
insulating material
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
US126981A
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English (en)
Inventor
Yoshida Susumu
Ohkoshi Akio
Nemoto Yasuyoshi
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.)
Sony Corp
Original Assignee
Sony 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 Sony Corp filed Critical Sony Corp
Application granted granted Critical
Publication of US3250942A publication Critical patent/US3250942A/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
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/80—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching

Definitions

  • This invention relates to a cathode-ray tube and, more particularly, to a cathode-ray tube having substantially no secondary electron emission from its electron beam deflection magnifying mesh screen.
  • One object of this invention is to provide acathoderay tube which has an electron beam deflection magnifying mesh screen from which secondary electrons are seldom emitted.
  • Another object of this invention is to provide a cathode-ray tube which has an anode, which sets up a particular electric field such that secondary electrons emitted from an electron beam deflection magnifying mesh screen are attracted to an anode.
  • a further object of this invention is to provide a cathode-ray tube which gives a clear picture on its fluorescent screen without being affected by stray secondary electrons emitted from an electron beam deflection magnifying mesh screen,
  • an electron beam deflection magnifying mesh screen for use in a cathode ray tube and comprises a mesh screen ofan electrical insulating material having low secondary electron emission ratio. Fastened to the insulating material is a layer of electrically conductive material.
  • the mesh screen is further adapted to be fastened to the inside of a cathode-ray tube at the base of a cone, with the insulating material forming the mesh surface which faces in the direction of the supply of electrons for the cathode-ray tube.
  • a curved mesh screen fo'r a cathode-ray tube having first and second anodes having a first layer of electrically insulating material having a low emission ratio and a second layer of an electrically conductive material.
  • the screen is adapted to be disposed in the cathode-ray tube between the first and second anodes with the layer of insulating material forming the mesh screen surface facing the source of electrons and is further adapted to be con- 'nected to an electric potential source lower than that of the first and second anodes.
  • a single figure is an enlarged schematic diagram, partially in section of a main part of a cathode-ray tube illustrating one embodiment of this invention.
  • FIG. 1 illustrates a tube proper and 2 is its cone shaped part and 3 is its neck part.
  • An electron gun assembly (not shown) may be arranged inside the neck and an electron beam deflection device such as a coil 4 is usually disposed outside the neck.
  • An electron beam e from the electron gun passes through the center axis of the tube into an electron beam deflection electromagnetic field of the deflection device 4 to be deflected and directed to a fluorescent screen (not shown).
  • the deflected electron beam 2 meets with a deflection magnifying mesh 5 in the direction of advance directly after deflection.
  • the mesh 5 is arranged inside the base of the cone shaped part, and this mesh is specifically constructed, as will hereinbelow be described, and to which such an electrical potential is applied so that a secondary electron which is caused by a primary electron impacting the mesh does not run into the fluorescent screen.
  • a special curved mesh 5 provided with an insulating layer 5b, on one side surface of a conductive or metallic mesh 5a, is disposed in the base of the cone shaped portion in such a manner that the .insulating layer 5b is on the side toward the electron gun.
  • Means are also provided for affording proper potentials to the mesh screen 5, anode 6 and a second anode 7.
  • the means illustrated is a voltage divider 8 which has fixed contacts at 9, 10 and 11 and resistive portions P P and P which are connected across the terminals of a direct current source S.
  • the contacts 9, 10 and 11 are connected to the mesh 5, the anode 6 and the anode 7, respectively.
  • the connections are such that an electric potential V is applied to the mesh 5 which is a little lower than a potential V applied to the first anode 6 disposed at the neck part 3 and considerably lower than the fluorescent screen potential, namely a potential V on the second anode 7.
  • the first anode 6 electric potential is 5 kv.
  • the second anode 7 potential is 10 kv.
  • an electric potential of about 4.9 kv. is impressed on themesh.
  • an insulation material such as glass which may be made in a mesh configuration by a conventional mechanical method such as embossing or the like.
  • the mesh may also be made by an electrical method such, for example, as causing an electron beam to scan a thin glass plate so as to cut it by melting. Subsequently, on one side surface of a ,mesh thus produced is deposited a proper electrically conducted metal by evaporation.
  • the secondary electron emission ratio decreases because of the insulation material layer 5b so that the number of free electrons e in the vicinity of the mesh is much reduced.
  • the emission of the secondary electrons may be avoided and screen made of an electrical insulating material having a law secondary emission ratio, a layer of electrically conductive material fastened to said electrical insulating material, said mesh screen being adapted to be fastened to the inside of a cathode-ray tube at the base of a cone with said electrically insulating material forming the mesh screen surface which faces in the direction of the supply of electrons for the cathode ray tube.
  • a screen for use as an electron beam deflection magnifier in a cathode-ray tube having first and second anodes comprising a curved screen having first and second layers, ,said first layer being made of an electrically insulating material having a law secondary emission ratio and said second layer being made of an electrically conductive material, said screen being adapted to be 20 disposed in the cathode-ray tube between the first and second anodes with the layer of electrically insulating material facing the source of electrons and being adapted 4 to be connected to an electric potential source that is lower than that applied to the first and second anodes.
  • 3. The electron beam deflection magnifying mesh screen in accordance with claim 2 in which said insulating material having low secondary emission properties is glass.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
US126981A 1960-08-08 1961-07-26 Cathode ray tube with improved deflection magnifying screen Expired - Lifetime US3250942A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3439860 1960-08-08

Publications (1)

Publication Number Publication Date
US3250942A true US3250942A (en) 1966-05-10

Family

ID=12413064

Family Applications (1)

Application Number Title Priority Date Filing Date
US126981A Expired - Lifetime US3250942A (en) 1960-08-08 1961-07-26 Cathode ray tube with improved deflection magnifying screen

Country Status (4)

Country Link
US (1) US3250942A (en, 2012)
DE (1) DE1220525B (en, 2012)
GB (1) GB916958A (en, 2012)
NL (1) NL267802A (en, 2012)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706896A (en) * 1969-07-16 1972-12-19 Licentia Gmbh Cathode-ray tube having planar grid accelerator adjacent and on screen side of beam deflectors
US3772553A (en) * 1972-06-19 1973-11-13 Hewlett Packard Co Secondary emission structure

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2487078A (en) * 1945-03-17 1949-11-08 Westinghouse Electric Corp Tube
US2622219A (en) * 1949-07-09 1952-12-16 Hartford Nat Bank & Trust Co Television image tube
US2858466A (en) * 1955-11-25 1958-10-28 Westinghouse Electric Corp Method of reducing secondary emission from bombarded surfaces
US2888601A (en) * 1954-04-29 1959-05-26 English Electric Valve Co Ltd Television and like camera tube arrangements
US2901661A (en) * 1955-03-01 1959-08-25 Rca Corp Television pickup tube circuit arrangements
US2916664A (en) * 1954-12-06 1959-12-08 Westinghouse Electric Corp Electron discharge device
US3013178A (en) * 1953-03-23 1961-12-12 Fairchild Camera Instr Co Focussing mask for cathode ray tube
US3035203A (en) * 1959-12-11 1962-05-15 Sylvania Electric Prod Cathode-ray tube
US3042832A (en) * 1959-04-16 1962-07-03 Abtronics Inc High-sensitivity cathode-ray tube
US3154710A (en) * 1958-11-13 1964-10-27 Motorola Inc Cathode-ray display system having electrostatic magnifying lens

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2487078A (en) * 1945-03-17 1949-11-08 Westinghouse Electric Corp Tube
US2622219A (en) * 1949-07-09 1952-12-16 Hartford Nat Bank & Trust Co Television image tube
US3013178A (en) * 1953-03-23 1961-12-12 Fairchild Camera Instr Co Focussing mask for cathode ray tube
US2888601A (en) * 1954-04-29 1959-05-26 English Electric Valve Co Ltd Television and like camera tube arrangements
US2916664A (en) * 1954-12-06 1959-12-08 Westinghouse Electric Corp Electron discharge device
US2901661A (en) * 1955-03-01 1959-08-25 Rca Corp Television pickup tube circuit arrangements
US2858466A (en) * 1955-11-25 1958-10-28 Westinghouse Electric Corp Method of reducing secondary emission from bombarded surfaces
US3154710A (en) * 1958-11-13 1964-10-27 Motorola Inc Cathode-ray display system having electrostatic magnifying lens
US3042832A (en) * 1959-04-16 1962-07-03 Abtronics Inc High-sensitivity cathode-ray tube
US3035203A (en) * 1959-12-11 1962-05-15 Sylvania Electric Prod Cathode-ray tube

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3706896A (en) * 1969-07-16 1972-12-19 Licentia Gmbh Cathode-ray tube having planar grid accelerator adjacent and on screen side of beam deflectors
US3772553A (en) * 1972-06-19 1973-11-13 Hewlett Packard Co Secondary emission structure

Also Published As

Publication number Publication date
DE1220525B (de) 1966-07-07
NL267802A (en, 2012)
GB916958A (en) 1963-01-30

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