US2689923A - Cathode-ray tube - Google Patents

Cathode-ray tube Download PDF

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Publication number
US2689923A
US2689923A US250983A US25098351A US2689923A US 2689923 A US2689923 A US 2689923A US 250983 A US250983 A US 250983A US 25098351 A US25098351 A US 25098351A US 2689923 A US2689923 A US 2689923A
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US
United States
Prior art keywords
deflection
cathode
coil
ray tube
layers
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
US250983A
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English (en)
Inventor
Janssen Peter Johanne Hubertus
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 US2689923A publication Critical patent/US2689923A/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
    • 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
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
    • H01J29/76—Deflecting by magnetic fields only
    • H01J29/762—Deflecting by magnetic fields only using saddle coils or printed windings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/70—Electron beam control outside the vessel
    • H01J2229/703—Electron beam control outside the vessel by magnetic fields
    • H01J2229/7031—Cores for field producing elements, e.g. ferrite

Definitions

  • This invention relates to cathode-ray tubes, having a coil for deflecting the electron beam, wherein the radius of curvature of the surface scanned by the beam exceeds the distance of this surface from the centre of the active length of the deflection coil.
  • Such a combination is, for example, employed in modern television receivers, in which the surface of the cathode-ray tube to be scanned is substantially flat and of such a size that the beam must be deflected over a large angle both for horizontal and vertical scanning.
  • this surface has a spherical shape and the centre of the sphere substantially coincides with the centre of the effective length of the deflection coil i. e. with the point at which the deflection action of the coil may be imagined to be concentrated, the displacement of the point of scanning spot over thesurface is proportional to the intensity of the deflecting magnetic field.
  • cathode-ray tubes having a substantially flat scanning surface are employed in combination with normal deflection coils producing a substantially homogeneous magnetic field, a raster having a pronounced cushion-like distortion and a poor linearity is obtained in the case of strong deflection, for example, in horizontal and vertical scanning in a television receiver.
  • the present invention has for its object to obviate the aforesaid drawback in a simple manner has the feature that the deflection coil comprises a shell consisting of at least two separated layers of ferromagnetic material surrounding the coil substantially throughout its active length.
  • the single accompanying figure is a crosssection of a coil system, according to one embodiment of the invention, in a plane at right angles to the longitudinal axis of the system and, at the centre of the active length.
  • the neck I of the cathode-ray tube is surrounded by a line-deflection coil consisting of coil halves 2 and 3, and a frame-deflection coil consisting of coil halves 4 and 5.
  • the coils may be of normal construction so that the individual turns (not shown) extend at right angles to the plane of the drawing and substantially parallel to the tube wall I also extending at right angles to the plane of the drawing.
  • the two deflection systems are surrounded by a shell consisting in this case of three layers E, I and 8 of ferromagnetic material, between which insulating layers 9 and ID are sandwiched.
  • the layers 6, 1 and 8 extend at right angles to the plane of the drawing substantially throughout the active length of the coils and surround them.
  • Each layer may consist of band-shaped material, the band being wound on the coil bases in such manner that the winding pitch corresponds to or slightly exceeds the width of the band so that, viewed in a longitudinal direction of the coil, the windings just do not overlap and, notwithstanding that, form a practically continuous surface so that the layers may be operative as magnetic short-circuit turns, with the result that the magnetic field is concentrated within these rings.
  • the magnetic flux successively will saturate the layer 6, the layer 1 and the layer 8 which involves a slower increase in strength of the magnetic deflection field than corresponds to the occurring amplitude of the deflection current, so that the beam of the cathode-ray tube is less deflected.
  • the total angle of deflection of the beam was ten layers consisting of mu metal having a thickness of 50 mu were used, which layers were separated by paper layers of mu thick.
  • a deflection coil system for a cathode ray tube in which the radius of curvature of a surface to be scanned exceeds the distance of this surface from the center of the active length of the coil system comprising a deflection coil and a ferromagnetic shell surrounding said coil, said 4 2.

Landscapes

  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Details Of Television Scanning (AREA)
US250983A 1950-11-01 1951-10-12 Cathode-ray tube Expired - Lifetime US2689923A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL157036 1950-11-01

Publications (1)

Publication Number Publication Date
US2689923A true US2689923A (en) 1954-09-21

Family

ID=19750506

Family Applications (1)

Application Number Title Priority Date Filing Date
US250983A Expired - Lifetime US2689923A (en) 1950-11-01 1951-10-12 Cathode-ray tube

Country Status (8)

Country Link
US (1) US2689923A (enrdf_load_stackoverflow)
BE (1) BE506783A (enrdf_load_stackoverflow)
CH (1) CH294532A (enrdf_load_stackoverflow)
DE (1) DE977535C (enrdf_load_stackoverflow)
ES (1) ES200197A1 (enrdf_load_stackoverflow)
FR (1) FR1044371A (enrdf_load_stackoverflow)
GB (1) GB691164A (enrdf_load_stackoverflow)
NL (1) NL78898C (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2830213A (en) * 1955-09-08 1958-04-08 Gen Electric Deflection coil
US3007087A (en) * 1958-06-04 1961-10-31 Gen Dynamics Corp Electromagnetic deflection coil
US3974421A (en) * 1973-11-09 1976-08-10 U.S. Philips Corporation Television deflection coil

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2155514A (en) * 1935-11-30 1939-04-25 Rca Corp Deflecting coil for cathode ray tubes
US2167379A (en) * 1936-02-28 1939-07-25 Rca Corp Cathode ray tube deflecting device
US2207777A (en) * 1937-11-16 1940-07-16 Rca Corp Cathode ray deflecting device

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL48160C (enrdf_load_stackoverflow) * 1936-03-03
GB476947A (en) * 1936-06-18 1937-12-20 Baird Television Ltd Improvements in or relating to magnetic deflecting means for electron discharge devices
DE743844C (de) * 1939-02-08 1944-01-04 Fernseh Gmbh Elektromagnetisches Ablenksystem fuer Elektronenstrahlroehren
US2333806A (en) * 1939-06-02 1943-11-09 Jefferson Electric Co Coil structure
BE440582A (enrdf_load_stackoverflow) * 1940-02-17
NL77952C (enrdf_load_stackoverflow) * 1948-07-28

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2155514A (en) * 1935-11-30 1939-04-25 Rca Corp Deflecting coil for cathode ray tubes
US2167379A (en) * 1936-02-28 1939-07-25 Rca Corp Cathode ray tube deflecting device
US2207777A (en) * 1937-11-16 1940-07-16 Rca Corp Cathode ray deflecting device

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2830213A (en) * 1955-09-08 1958-04-08 Gen Electric Deflection coil
US3007087A (en) * 1958-06-04 1961-10-31 Gen Dynamics Corp Electromagnetic deflection coil
US3974421A (en) * 1973-11-09 1976-08-10 U.S. Philips Corporation Television deflection coil

Also Published As

Publication number Publication date
ES200197A1 (es) 1952-03-01
BE506783A (enrdf_load_stackoverflow)
GB691164A (en) 1953-05-06
CH294532A (de) 1953-11-15
NL78898C (enrdf_load_stackoverflow)
FR1044371A (fr) 1953-11-17
DE977535C (de) 1967-01-12

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