US2513929A - Beam centering device for cathode-ray tubes - Google Patents

Beam centering device for cathode-ray tubes Download PDF

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Publication number
US2513929A
US2513929A US28315A US2831548A US2513929A US 2513929 A US2513929 A US 2513929A US 28315 A US28315 A US 28315A US 2831548 A US2831548 A US 2831548A US 2513929 A US2513929 A US 2513929A
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US
United States
Prior art keywords
sleeve
cathode ray
magnet
ring
neck
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
US28315A
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English (en)
Inventor
Richard B Gethmann
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.)
General Electric Co
Original Assignee
General Electric 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 General Electric Co filed Critical General Electric Co
Priority to US28315A priority Critical patent/US2513929A/en
Priority to GB13137/49A priority patent/GB666907A/en
Priority to FR986384D priority patent/FR986384A/fr
Application granted granted Critical
Publication of US2513929A publication Critical patent/US2513929A/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
    • H01J29/54—Arrangements for centring ray or beam

Definitions

  • My invention relates to cathode ray tubes of the type which are used in television receivers and has for its object to provide a beam centering device which is simple in adjustment and construction.
  • cathode ray tubes which are used in television receivers, it is customary to employ a device for focussing the cathode ray beam and an additional device for deflecting the beam through transverse paths for scanning fluorescent end walls provided in such tubes.
  • a device for focussing the cathode ray beam and an additional device for deflecting the beam through transverse paths for scanning fluorescent end walls provided in such tubes.
  • the cathode ray beam itself be accurately centered relative to the axis of the tube.
  • the centering force is applied to the beam prior to: the focussing force, it has been found that a distortion is produced around the edge of the reproduced screen which is known as neck shadow.
  • One of the features of my invention consists in employing two permanent magnets having high directional characteristics and; adapted to provide a magnetic field of uniform cross section across a narrow portion of the neck of the cathode ray tube.
  • One of the magnets is adjustable in position relative to a magnetic shunt to control the strength and direction of the centering force.
  • the deflection yoke 9 may consist of a plurality of coils (not shown) for deflecting the cathode ray beam in both horizontal and vertical directions to scan the fluorescent screen 3 in the usual manner.
  • a beam centering device Positioned between the focus coil 8 and the deflection yoke 2 is a beam centering device comprising a non-magnetic sleeve l 0 having a. longitudinal slot I l therein.
  • Supported on the sleeve Ill are a pair of ring-shaped permanent magnets l2, I3.
  • the construction of the beam centering device may be more clearly seen in the enlarged view of Fig. 2.
  • the focus coil 8 includes an end plate l4 formed of steel or any other suitable ferromagnetic material having a neck i5 which engages the outer surface of the tube l.
  • a spacer 16 Positioned between the sleeve Hiand the tubing 1 is a spacer 16 which supports sleeve ill.
  • One end of sleeve It! is arranged to slide over neck iii of the end plate of the focus coil.
  • the end of sleeve l0 remote from end plate M has a groove H which receives the peripherally incomplete permanent magnet 13.
  • the adjacent ends of the magnet I 3 are bentinwardly to engage slot H inthe end of sleeve l0.
  • Permanent magnet 12 for reasons to be pointed out later, is larger than magnet i3 and likewise has inwardly turned ends which flt into slot H.
  • Magnets l2, l3 preferably are formed of any suitable permanent magnet material having a magnetic materials of the copper-nickel-iron alloy type, known as cunife, are well adapted for 7 use as the rings l2, it, other magnetic materials, such as the copper-nickel-cobalt alloys including cunico, and the silver-manganese-aluminum alloys including silmanal, are also well adapted for use in this construction. Similarly,
  • the magnet I3 is provided and is so magnetized that it provides a flux which is adjusted both in field strength and direction to produce a deflection of the cathode ray beam in adirection opposite to that produced by the shunted permanent magnet I2.
  • the strength of ring 13 is sufilcient in magnitude approximately to balance out the deflection produced by magnet l2 when shunted by neck 15.
  • the metallic sleeve I8 is provided on its periphery with a pair of diametrically positioned outwardly protruding portions l9.
  • Adjustably supported for axial movement along the outer surface of the sleeve I3 is a first ring-shaped permanent magnet 2
  • the neck l5 functions as a magnetic shunt for the permanent magnet 2!.
  • the degree of shunting action obtained depends upon the extent to which the sleeve [8 telescopes neck 15 and the position. of magnet 2i relative to the right-hand edge of sleeve l8.
  • a first permanent magnet ring 21- is supported upon and preferably fixed, a by cementing, to a non-magnetic supporting sleeve 28, while the second permanent magnet ring 29 is arranged concentric and coplanar with ring 27.
  • the ring 29 is provided with tabs 30 by means of which it may be rotated relative to ring 21.
  • a non-magnetic sleeve 31 may be positioned between rings 21, 29 if desired.
  • a non-magnetic shunt such as the shunt l5 illustrated in connection with the embodiment of Fig. 7, is not required.
  • a beam centering device for a cathode ray tube of the type having a neck portion and means for projecting a cathode ray beam axially of said neck portion comprising, a non-magnetic supporting sleeve adapted to encircle the neck of a cathode ray tube, a pair of peripherally incomplete ring-shaped permanent magnets supported on said sleeve, said magnets producing parallel uniform magnetic fields across said sleeve in a direction normal to the axis thereof, the field of one of said magnets having a polarity opposite to that of the other, a first of said magnets being attached to said sleeve in a predetermined position axially thereof, the other of said magnets being movable axially of said sleeve, said sleeve and other magnet having portions resisting rotation of said other magnet relative to said sleeve, and magnetic means extending within said sleeve for shunting a variable amount of the flux of said other magnet

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US28315A 1948-05-21 1948-05-21 Beam centering device for cathode-ray tubes Expired - Lifetime US2513929A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US28315A US2513929A (en) 1948-05-21 1948-05-21 Beam centering device for cathode-ray tubes
GB13137/49A GB666907A (en) 1948-05-21 1949-05-17 Improvements in and relating to cathode ray tubes
FR986384D FR986384A (fr) 1948-05-21 1949-05-20 Perfectionnements aux tubes cathodiques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US28315A US2513929A (en) 1948-05-21 1948-05-21 Beam centering device for cathode-ray tubes

Publications (1)

Publication Number Publication Date
US2513929A true US2513929A (en) 1950-07-04

Family

ID=21842756

Family Applications (1)

Application Number Title Priority Date Filing Date
US28315A Expired - Lifetime US2513929A (en) 1948-05-21 1948-05-21 Beam centering device for cathode-ray tubes

Country Status (3)

Country Link
US (1) US2513929A (fr)
FR (1) FR986384A (fr)
GB (1) GB666907A (fr)

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2539156A (en) * 1949-01-19 1951-01-23 Tele Tone Radio Corp Ion trap magnet
US2544898A (en) * 1949-12-31 1951-03-13 Guardian Electric Mfg Co Centering device for beams of cathode-ray tubes
US2552341A (en) * 1949-02-03 1951-05-08 Clarostat Mfg Co Inc Magnetic structure for use in ion-traps
US2552342A (en) * 1949-11-17 1951-05-08 Clarostat Mfg Co Inc Magnetic structure for use in ion-traps
US2553792A (en) * 1949-10-01 1951-05-22 Indiana Steel Products Co Ion trap and centering magnet assembly
US2569327A (en) * 1948-08-31 1951-09-25 Rca Corp Electron beam bender
US2569517A (en) * 1949-09-09 1951-10-02 Du Mont Allen B Lab Inc Magnet for cathode-ray tube ion traps
US2574039A (en) * 1951-02-17 1951-11-06 All Star Products Inc Magnetic centering device for cathode ray tubes
US2575067A (en) * 1948-05-13 1951-11-13 Clarostat Mfg Co Inc Ion trap
US2597465A (en) * 1951-03-23 1952-05-20 Emmer Milton Beam deflector for cathode-ray tubes
US2597298A (en) * 1949-02-18 1952-05-20 Pye Ltd Beam centering device for cathoderay tubes
US2598916A (en) * 1951-08-11 1952-06-03 All Star Products Inc Ion trap of uniform flux density
US2603550A (en) * 1951-07-12 1952-07-15 Philco Corp Method of aligning cathode-ray tube assemblies
US2653262A (en) * 1951-06-05 1953-09-22 Philco Corp Control device
US2663815A (en) * 1950-09-26 1953-12-22 Clarostat Mfg Co Inc Ion trap
US2717324A (en) * 1950-05-04 1955-09-06 Emi Ltd Cathode ray tubes
US2817782A (en) * 1954-07-09 1957-12-24 Rca Corp Cathode ray tube deflection apparatus
US2854598A (en) * 1955-11-21 1958-09-30 Baermann Max Magnetic field adjuster for television picture tubes
US2885586A (en) * 1954-12-24 1959-05-05 Sylvania Electric Prod Television receiver
US2898493A (en) * 1956-05-31 1959-08-04 Sylvania Electric Prod Method and apparatus for controlling electron beams
US2922908A (en) * 1955-08-31 1960-01-26 Westinghouse Electric Corp Retaining device
US3303444A (en) * 1964-07-16 1967-02-07 Videocraft Mfg Co Electron beam convergence and deflection apparatus
US3303443A (en) * 1964-08-31 1967-02-07 Rca Corp Magnetic device having elliptically shaped opening

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1067941B (fr) * 1959-10-29
GB731451A (en) * 1952-10-23 1955-06-08 Dennis Henry Covill Improvements in or relating to arrangements for use with cathode ray tubes

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB464637A (en) * 1934-10-19 1937-04-21 Fernseh Ag Improvements in or relating to magnetic deflecting means for cathode-ray tubes
US2102421A (en) * 1934-07-12 1937-12-14 Gen Electric Cathode ray oscillograph
US2200039A (en) * 1937-11-01 1940-05-07 Emi Ltd Permanent magnet device for producing axially symmetrical magnetic fields
US2224933A (en) * 1934-02-09 1940-12-17 Loewe Radio Inc Magnetic distortion correcting means for cathode ray tubes
US2418487A (en) * 1944-03-31 1947-04-08 Bell Telephone Labor Inc Cathode ray magnetic focusing device
US2431077A (en) * 1943-08-31 1947-11-18 Rca Corp Cathode-ray tube with revolving magnets and adjustable sleeve
US2442975A (en) * 1943-08-31 1948-06-08 Rca Corp Focusing system
US2456474A (en) * 1946-07-02 1948-12-14 Gen Electric Electric discharge device
US2460609A (en) * 1946-01-24 1949-02-01 Rca Corp Beam aligning apparatus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2224933A (en) * 1934-02-09 1940-12-17 Loewe Radio Inc Magnetic distortion correcting means for cathode ray tubes
US2102421A (en) * 1934-07-12 1937-12-14 Gen Electric Cathode ray oscillograph
GB464637A (en) * 1934-10-19 1937-04-21 Fernseh Ag Improvements in or relating to magnetic deflecting means for cathode-ray tubes
US2200039A (en) * 1937-11-01 1940-05-07 Emi Ltd Permanent magnet device for producing axially symmetrical magnetic fields
US2431077A (en) * 1943-08-31 1947-11-18 Rca Corp Cathode-ray tube with revolving magnets and adjustable sleeve
US2442975A (en) * 1943-08-31 1948-06-08 Rca Corp Focusing system
US2418487A (en) * 1944-03-31 1947-04-08 Bell Telephone Labor Inc Cathode ray magnetic focusing device
US2460609A (en) * 1946-01-24 1949-02-01 Rca Corp Beam aligning apparatus
US2456474A (en) * 1946-07-02 1948-12-14 Gen Electric Electric discharge device

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2575067A (en) * 1948-05-13 1951-11-13 Clarostat Mfg Co Inc Ion trap
US2569327A (en) * 1948-08-31 1951-09-25 Rca Corp Electron beam bender
US2539156A (en) * 1949-01-19 1951-01-23 Tele Tone Radio Corp Ion trap magnet
US2552341A (en) * 1949-02-03 1951-05-08 Clarostat Mfg Co Inc Magnetic structure for use in ion-traps
US2597298A (en) * 1949-02-18 1952-05-20 Pye Ltd Beam centering device for cathoderay tubes
US2569517A (en) * 1949-09-09 1951-10-02 Du Mont Allen B Lab Inc Magnet for cathode-ray tube ion traps
US2553792A (en) * 1949-10-01 1951-05-22 Indiana Steel Products Co Ion trap and centering magnet assembly
US2552342A (en) * 1949-11-17 1951-05-08 Clarostat Mfg Co Inc Magnetic structure for use in ion-traps
US2544898A (en) * 1949-12-31 1951-03-13 Guardian Electric Mfg Co Centering device for beams of cathode-ray tubes
US2717324A (en) * 1950-05-04 1955-09-06 Emi Ltd Cathode ray tubes
US2663815A (en) * 1950-09-26 1953-12-22 Clarostat Mfg Co Inc Ion trap
US2574039A (en) * 1951-02-17 1951-11-06 All Star Products Inc Magnetic centering device for cathode ray tubes
US2597465A (en) * 1951-03-23 1952-05-20 Emmer Milton Beam deflector for cathode-ray tubes
US2653262A (en) * 1951-06-05 1953-09-22 Philco Corp Control device
US2603550A (en) * 1951-07-12 1952-07-15 Philco Corp Method of aligning cathode-ray tube assemblies
US2598916A (en) * 1951-08-11 1952-06-03 All Star Products Inc Ion trap of uniform flux density
US2817782A (en) * 1954-07-09 1957-12-24 Rca Corp Cathode ray tube deflection apparatus
US2885586A (en) * 1954-12-24 1959-05-05 Sylvania Electric Prod Television receiver
US2922908A (en) * 1955-08-31 1960-01-26 Westinghouse Electric Corp Retaining device
US2854598A (en) * 1955-11-21 1958-09-30 Baermann Max Magnetic field adjuster for television picture tubes
US2898493A (en) * 1956-05-31 1959-08-04 Sylvania Electric Prod Method and apparatus for controlling electron beams
US3303444A (en) * 1964-07-16 1967-02-07 Videocraft Mfg Co Electron beam convergence and deflection apparatus
US3303443A (en) * 1964-08-31 1967-02-07 Rca Corp Magnetic device having elliptically shaped opening

Also Published As

Publication number Publication date
FR986384A (fr) 1951-07-31
GB666907A (en) 1952-02-20

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