US3899710A - Color cathode ray tube with temperature-responsive color purity magnets - Google Patents

Color cathode ray tube with temperature-responsive color purity magnets Download PDF

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Publication number
US3899710A
US3899710A US329049A US32904973A US3899710A US 3899710 A US3899710 A US 3899710A US 329049 A US329049 A US 329049A US 32904973 A US32904973 A US 32904973A US 3899710 A US3899710 A US 3899710A
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United States
Prior art keywords
screen
magnetic
temperature
cathode ray
tube
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Expired - Lifetime
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US329049A
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English (en)
Inventor
Hiromasa Machida
Noboru Yamaguchi
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Sony Corp
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Sony Corp
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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
    • H01J29/70—Arrangements for deflecting ray or beam
    • H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
    • 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
    • H01J29/006—Arrangements for eliminating unwanted temperature effects
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/56—Correction of beam optics
    • H01J2229/563—Aberrations by type
    • H01J2229/5637—Colour purity

Definitions

  • This invention relates generally to means for avoiding beam mislanding in a color cathode ray tube having a color phosphor screen, and more particularly to means of compensating for such mislanding caused by temperature variations in the color cathode ray tube.
  • One conventional system is to hold the mask by a bimetallic support to change the position of the mask in the tube relative to the screen in response to temperature change.
  • Another compensating system uses an auxiliary beam deflection coil in addition to the main deflection coil. The current in the auxiliary beam deflection coil is changed in response to the mask temperature to change the electron beam path in order to avoid the mislanding of the electron beams.
  • an object of this invention is to provide a color cathode ray tube arrangement which maintains excellent color purity with simple correcting means for compensating for temperature-caused deterioration's in color purity.
  • Another object of this invention is to provide a color cathode ray tube arrangement wherein mislanding of electron beams on the screen of the color cathode ray tube caused by temperature variations in the mask and screen is compensated for by simple correcting means that may be located on the funnel portion of the tubev
  • Still another object of this invention is to provide a color cathode ray tube arrangement in which temperature-induced mislanding of the electron beams is prevented by a temperature-responsive permanent magnetic device of simple construction.
  • a further object of this invention is to provide a simple color-purity correcting means comprising a temperature-responsive permanent magnetic device.
  • a color cathode ray tube arrangement for compensating for electron beam mislanding comprises a temperature-responsive magnetic device. the magnetic flux density of which changes in response to temperature variation.
  • the magnetic compensating means is located at a predetermined position between the beam deflection center of the tube and the screen in order to modify by the magnetic flux originated from the magnetic device the paths of the beams.
  • thermoresponsive magnetic device Various devices may be used as the temperatureresponsive magnetic device.
  • An example of such a temperature-responsive magnetic device is a permanent magnet which will change magnetic flux originated therefrom in response to temperature changes.
  • a preferable example is a combination of a normal permanent magnet and a temperature-responsive magnetic material whose permeability changes in response to temperature changes.
  • FIG. 1 is a plan view of one example of a temperature-responsive magnetic device employed in a color cathode ray tube temperature compensating arrangement according to the invention.
  • FIG. 2 is a cross-sectional view of the device shown in FIG. 1.
  • FIG. 3 is a graph that shows the temperatureresponsive characteristic of the device shown in FIGS. 1 and 2.
  • FIGS. 4 and 5 are perspective views illustrating the color cathode ray tube temperature compensating arrangements according to the invention.
  • FIG. 6 is a cross'sectional view of a fragment of the color cathode ray tube arrangements depicted in FIGS. 4 and 5.
  • FIGS. 7 to 10, inclusive are diagrams for explaining compensation for mislanding of electron beams by means of the invention.
  • FIG. 11 is a perspective view of another example of the color cathode ray tube arrangement according to the invention with a section of the tube broken away to show the interior construction thereof.
  • FIGS. 1 and 2 show an embodiment of a temperature-responsive magnetic device 1 used in accordance with this invention.
  • the device I designates generally a temperature-responsive magnetic device which consists of a permanent magnet 2 and a temperatureresponsive magnetic material 3.
  • the permanent magnet 2 is made of, for example, Ba-ferrite containing BaCO and Fe O in the ratio of 15:85 by mol.% and may be formed as a disc magnetized along its diameter.
  • the temperature-responsive magnetic material 3 may be made of Mn Zn-ferrite and formed as a disc having a recess bounded by an annular projection at the periphery of one surface.
  • the disc 3 has a magnetic permeability that decreases as the temperature increases.
  • An example of a suitable material for the disc 3 is a MnZn-ferrite composed of Fe O MnCO and ZnO combined in the ratio of 50:27:23 by mol.%.
  • a MnZn-ferrite composed of Fe O MnCO and ZnO combined in the ratio of 50:27:23 by mol.%.
  • the relationship between the temperature and the flux density of the external magnetic field from the magnetic device 1 can be made such as shown in the graph of FIG. 3 in which the ordinate represents the magnetic flux density in Gauss and the abscissa temperature in C.
  • the permanent magnet 2 and the temperature-responsive magnetic material 3 used in the device 1 be limited to the configurations mentioned above. They can be formed, for example, with rectangular perimeters with one side of the permanent magnet and its rectangular perimeter covered by the magnetic material. Other polygonal forms may also be used.
  • temperature-responsive magnetic devices 1 each of which is constructed as mentioned above, are mounted on a color cathode ray tube 4 at the corners of its funnel portion 4F, as shown in FIG. 4.
  • a color cathode ray tube provided with a beam selecting mask having a number of vertical slits and a phosphor screen in which respective sets of color phosphor strips extended in the vertical direction are arranged successively along the horizontal beam scanning direction, a shift of the landing position of the electron beams in the horizontal scanning direction, namely in the left and right direction, becomes a problem that must be corrected. Accordingly, it may be possible in such a case that further temperature-responsive magnetic devices similar to the device 1 in FIG.
  • the respective temperatureresponsive magnetic devices 1 be mounted on the tube 4 in such a manner that the side surface of each permanent magnet 2 which is not covered with the temperature-responsive magnetic material 3 faces away from the tube, as shown in FIG. 6.
  • FIGS. 7 and 8 illustrate how mislanding of electron beams may be prevented by mounting the temperature responsive magnetic device I in the manner described above.
  • the magnetic device 1 has the characteristic such as is shown in FIG. 3 and is mounted on the funnel portion 4F of the tube 4 in a manner to make the magnetized direction of the permanent magnet 2 perpendicular to the plane of the sheet of FIG. 7, the magnetic field H+ produced by the permanent magnet 2 will be directed into the plane of the drawing in the tube 4, as indicated by the X within the circle.
  • an electron beam 5 deflected by a deflection coil follows the path shown by the solid line in FIG. 7, while if there is a magnetic field H+ produced by the device I, the electron beam 5 is subjected to a force designated by an arrow F+ and is deflected to the path shown by the broken line.
  • a typical vertical slit or aperture 6a of the beam selecting mask is positioned as shown in FIG. 8 at room temperature.
  • An electron beam having passed through a virtual deflection center 7 on the tube axis 8 follows along a path shown by the solid line 50 through the aperture 6a.
  • the position of the aperture is shifted to the position 6b.
  • the electron beam follows a path shown by the solid line 5b in FIG. 8.
  • the magnetic device is mounted on the tube 4, the electron beam is deflected a little as shown by the broken line 5A at room temperature because the magnetic field I-I+ produced by the magnetic device 1 is weak at room temperature as described above.
  • the electron beam lands at substantially the same position on the phosphor screen 9 irrespective of temperature changes that cause thermal expansion or distortion of the beam selecting mask. It will be easily realized that the electron beams directed along other paths will also land on respective constant positions on the screen.
  • the temperature-responsive magnetic device 1 has a relationship between the magnetic flux density and temperature that is the reverse of that shown in FIG. 3. That is to say, as the temperature goes down, the magnetic flux density of the external magnetic field from the magnetic device 1 increases, while as the temperature rises, the magnetic flux density decreases. Mislanding of electron beams can also be prevented by the use of such a temperature-responsive magnetic device I. With reference to FIGS. 9 and 10, such a case will now be described.
  • the temperature-responsive magnetic device 1 is mounted on the tube 4 in such a manner that the magnetic field I-I- from the magnetic device I passes through the tube 4 in the direction into the plane of the drawing. This is opposite to the direction of the flux H+ in FIG. 7.
  • the electron beam 5 is subjected to the force shown by an arrow F- by the magnetic field H- and hence is deflected as shown by the broken line in FIG. 9.
  • the electron beam having passed through the virtual deflection center 7 on the tube axis 8 is deflected more at room temperature, as shown by the broken line 5A, since the magnetic field H- is greatest when the tube structure is at room temperature.
  • the electron beam is deflected less as shown by the broken line 5B in FIG. 10. Accordingly, it will be understood that in this case the landing position of the electron beam 5 on the phosphor screen 9 of the tube 4 is kept constant irrespective of thermal expansion or distortion of the beam selecting mask due to temperature variations.
  • the temperature responsive magnetic device 1 is not restricted to being mounted on the funnel portion 4F of the tube 4, but it may be mounted on a holder of the deflection coil or a frame for the beam selecting mask 6 inside the tube 4 with the same effect mentioned above. In the case of mounting the device 1 on the frame 10, variation in temperature of the beam selecting mask 6 can be directly detected by the magnetic device I.
  • a color cathode ray tube arrangement comprising:
  • A. a color cathode ray tube comprising:
  • a color phosphor screen comprising areas arranged in a predetermined pattern to emit light of different colors when struck by electrons
  • a beam selecting element disposed near said screen comprising electron passages positioned relative to said areas to allow said electron beams to land on predetermined areas of said screen according to the directions along which said beams pass through said passages;
  • thermoresponsive magnetic means provided on said tube for compensating for mislanding of said electron beams on incorrect ones of said areas of said screen due to thermal expansion of said beam selecting element resulting in displacement of at least some of said passages relative to their respective areas of said screen, said temperature responsive magnetic means comprising:
  • a magnetic shunt element having temperature responsive variable permeability, said magnetic shunt element forming a path for at least a part of the magnetic flux originating in said permanent magnet and being located on said tube to be heated by heat from said beam selecting element to change the intensity of magnetic flux from said magnetic means with temperature variations in said tube to cause the path of said electron beams landing on the screen to change in response to said thermal expansion of the beam selecting element thereby to maintain excellent color purity of light emitted by said screen, said magnetic element being formed into a block-like shape having a recess on one surface, and said permanent magnet being placed in said recess.
  • a color cathode ray tube arrangement according to claim 1, wherein said magnetic element is formed into a disc shape having a pair of opposite flat surfaces one of which is provided with said recess therein and said permanent magnet is also formed into a disc shape having a pair of opposite flat surfaces and placed in said recess with one of said flat surfaces of said magnet exposed to the outside.

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  • Video Image Reproduction Devices For Color Tv Systems (AREA)
US329049A 1972-02-03 1973-02-02 Color cathode ray tube with temperature-responsive color purity magnets Expired - Lifetime US3899710A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP1972014377U JPS5150426Y2 (fr) 1972-02-03 1972-02-03

Publications (1)

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US3899710A true US3899710A (en) 1975-08-12

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Country Status (7)

Country Link
US (1) US3899710A (fr)
JP (1) JPS5150426Y2 (fr)
CA (1) CA960742A (fr)
FR (1) FR2170277B1 (fr)
GB (1) GB1415596A (fr)
IT (1) IT978773B (fr)
NL (1) NL175769C (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4034324A (en) * 1974-09-20 1977-07-05 Tokyo Shibaura Electric Co., Ltd. Deflection device for use in color television receiver
US4143345A (en) * 1978-06-06 1979-03-06 Rca Corporation Deflection yoke with permanent magnet raster correction
US4145677A (en) * 1976-08-20 1979-03-20 Hitachi, Ltd. Color misalignment correction device for color picture tube
US4198614A (en) * 1978-11-06 1980-04-15 Rca Corporation Deflection yoke assembly including a beam positioning magnet arrangement
US5023509A (en) * 1989-10-27 1991-06-11 Rca Licensing Corp. Color CRT-yoke combination having conforming corrective magnetic field means attached to the CRT
US6586870B1 (en) * 1999-04-30 2003-07-01 Sarnoff Corporation Space-saving cathode ray tube employing magnetically amplified deflection
US6674230B1 (en) * 1999-04-30 2004-01-06 Sarnoff Corporation Asymmetric space-saving cathode ray tube with magnetically deflected electron beam
US20040095054A1 (en) * 2001-03-16 2004-05-20 Jong-Eon Choi Color cathode ray tube

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1204132A1 (fr) * 2000-11-02 2002-05-08 Matsushita Display Devices (Germany) GmbH Tube image couleur

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2972073A (en) * 1955-08-31 1961-02-14 Rca Corp Electron beam controlling apparatus
US3296570A (en) * 1963-09-23 1967-01-03 Mitsubishi Electric Corp Device for correcting distortion of deflection in television receiver
US3512035A (en) * 1968-02-27 1970-05-12 Matsushita Electric Ind Co Ltd Convergence device for color television receiver
US3573525A (en) * 1967-11-21 1971-04-06 Sony Corp Color purity temperature compensation system for a color picture tube
US3623151A (en) * 1970-07-13 1971-11-23 Denki Onkyo Co Ltd Convergence yoke cores for cathode-ray tubes

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2972073A (en) * 1955-08-31 1961-02-14 Rca Corp Electron beam controlling apparatus
US3296570A (en) * 1963-09-23 1967-01-03 Mitsubishi Electric Corp Device for correcting distortion of deflection in television receiver
US3573525A (en) * 1967-11-21 1971-04-06 Sony Corp Color purity temperature compensation system for a color picture tube
US3512035A (en) * 1968-02-27 1970-05-12 Matsushita Electric Ind Co Ltd Convergence device for color television receiver
US3623151A (en) * 1970-07-13 1971-11-23 Denki Onkyo Co Ltd Convergence yoke cores for cathode-ray tubes

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4034324A (en) * 1974-09-20 1977-07-05 Tokyo Shibaura Electric Co., Ltd. Deflection device for use in color television receiver
US4145677A (en) * 1976-08-20 1979-03-20 Hitachi, Ltd. Color misalignment correction device for color picture tube
US4143345A (en) * 1978-06-06 1979-03-06 Rca Corporation Deflection yoke with permanent magnet raster correction
US4198614A (en) * 1978-11-06 1980-04-15 Rca Corporation Deflection yoke assembly including a beam positioning magnet arrangement
US5023509A (en) * 1989-10-27 1991-06-11 Rca Licensing Corp. Color CRT-yoke combination having conforming corrective magnetic field means attached to the CRT
US6586870B1 (en) * 1999-04-30 2003-07-01 Sarnoff Corporation Space-saving cathode ray tube employing magnetically amplified deflection
US6674230B1 (en) * 1999-04-30 2004-01-06 Sarnoff Corporation Asymmetric space-saving cathode ray tube with magnetically deflected electron beam
US20040095054A1 (en) * 2001-03-16 2004-05-20 Jong-Eon Choi Color cathode ray tube

Also Published As

Publication number Publication date
DE2305162B2 (de) 1976-09-16
JPS4890525U (fr) 1973-10-31
FR2170277B1 (fr) 1977-08-19
JPS5150426Y2 (fr) 1976-12-04
DE2305162A1 (de) 1973-08-16
NL7301612A (fr) 1973-08-07
FR2170277A1 (fr) 1973-09-14
NL175769B (nl) 1984-07-16
IT978773B (it) 1974-09-20
GB1415596A (en) 1975-11-26
CA960742A (en) 1975-01-07
NL175769C (nl) 1984-12-17

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