US2834902A - Deflection system for cathode ray tubes - Google Patents

Deflection system for cathode ray tubes Download PDF

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Publication number
US2834902A
US2834902A US444298A US44429854A US2834902A US 2834902 A US2834902 A US 2834902A US 444298 A US444298 A US 444298A US 44429854 A US44429854 A US 44429854A US 2834902 A US2834902 A US 2834902A
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United States
Prior art keywords
plates
cathode ray
deflection
electron beam
zone
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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
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US444298A
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English (en)
Inventor
Gundert Eberhard
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Telefunken AG
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Telefunken AG
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Filing date
Publication date
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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
    • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
    • H01J29/74—Deflecting by electric fields only

Definitions

  • the .major axis of this ellipse isin the plane of the direction of the deection.
  • the deiection plates so that they provide a zone of decreasing teld intensity in that area where the ,beam is being deected. 'Ihis decreasing ield intensity must be established in a plane perpendicular to the plane of the deection.
  • unsymmetrical dellecting system -one of the plates may be grounded or .directly connected to the anode of the cathode ray tube,
  • the deflection astigmatism is overcome by positioning lthe zone of decreasing field intensity between the inlet and the outlet edges of the deecting plates and simultaneously providing a zone p of uniform field intensity between the ⁇ lirst zone and the outlet edges of the deecting plates.
  • a second object of the present invention is to provide a new and improved method and apparatus for eliminating deflection astigmatism in cathode ray tubes using l electrostatic beam deection.
  • Still another object of the present invention is to provide a new and improved combination of deecting electric fields for beam deflection purposes in cathode ray p l tubes.
  • a further object of the present invention is to provide an improved shape for deflecting plates in electrostatically il deected cathode ray tubes.
  • the present invention includes a method of preventing astigmatic distortion in a cathode l ray tube using a pair of deecting plates having inlet and outlet edges for electrostatic deflection of an electron beam passing between the plates in direction from the ICC inlet edges to the outlet edges which comprises'estab' lishing in a rst zone between the plates, spaced from the outlet edges, an electric eld varying in intensity in a direction transverse to the direction of the plane of d ⁇ flection ofthe electron beam, and establishing in a second zone between the rst zone and the outlet edges ari electric iield of uniform intensity.
  • Fig. 1 is a transverse cross-sectional view taken on the line B-B of Fig. 2;
  • Fig. 2 is a plan view of the neck of a cathode ray tube showing one embodiment of a deflecting plate incorporating the principles of the present invention
  • Fig. 3 is a transverse cross-sectional view taken on the line A-A of Fig. 2;
  • Fig. 4 is a longitudinal cross-sectional view of the neck of a cathode ray tube showing a second embodiment of an electrostatic deflection system incorporating the principles ,of the present invention
  • Fig. 5 is a plan view of a third embodiment of apparatus using the principles of the present invention.
  • Fig. 6 is a cross-sectional view of a cathode ray tube showing the method of mounting deflection plates shaped in the manner of the present invention.
  • Figs. 1 and 2 the neck of a cathode ray tube is shown.
  • the dotted line 20 in Fig. 1 indicates the path of an undeecte-d electron beam proceeding from the cathode to the screen of the cathode ray tube in the direction of the arrow 30.
  • Diametrieally opposed to each other Iabout the electron beam path 2t) are two deflecting plates 3 and 4 mounted in the neck 1 of the cathode ray tube. At the inlet edges 3a and 4a of the detlecting plates 3 and 4 respectively, the plates are essentially parallel to one another and small in width. At the center portions of the dellecting plates 3 and 4 are re-entrant surfaces 5 and 6 respectively. The outlet edges 3b and 4b of the dellecting plates are at a slight angle to one another and are substantially wider than the inlet edges 3a and 4a.
  • One side of a conventional D. C. power supply 31 is shown connected to deflecting plate 3.
  • the other side of power supply 31 is connected to ground through a variable resistor 32.
  • the plate 4 is also shown connected to ground.
  • an electrostatic iield is set up between the plates.
  • the pattern of this electrostatic eld is indicated in Fig. '3 by the dotted lines 21.
  • Fig. 3 it can be'seen that a strong electric field is established at the axis of the cathode ray tube and the path 20 of the undeected electron beam.
  • the field intensity decreases between the deflecting plates Vin a direction transverse to the deflection plane of the electron beam.
  • One zone provides an electric lield varying in intensity in a direction transverse to the direction of the plane of deflection of the electron beam and spaced from the outlet edges 3a and 34h.
  • the other zone provides an electric eld of uniform intensity and is located between the first zone and the outlet edges '3b and 4b of the deflection plates.
  • Fig. '4. is shown a second embodiment of apparatus incorporating the principles of the present invention.
  • openings 3 and 9 are provided in the plates. lt is apparent that this will have an effect similar to that described above and illustrated in Fig. 3. That is, at the center portions 8 and 9 of the deecting plates 4 and 3 respectively, the electric field intensity will decrease in a plane perpendicular to the deflecting plane of the electron beam.
  • shields 12 are provided about the openings 8 and 9. The purpose of these shields is to prevent any of the other potentials present in the cathode ray tube from affecting the path of the electron beam.
  • a third embodiment incorporating the prin- ⁇ ciples of the present invention is illustrated.
  • This ernbodiment includes narrow inlet edges 11 of the deflecting plates and wide outlet edges 10. It is apparent that at the center portion of the deflecting plates between the inletedges 11 and the outlet edges 10 a decreasing field intensity is provided in a plane perpendicular to the deliecting plane of the electron beam. Near the outlet edges of the deflecting plates, however, the electric field is uniform in a plane perpendicular to the deflection plane of the electron beam.
  • Fig. 6 the method of mounting deecting plates 3 and 4 in the neck of the cathode ray tube is shown.
  • the plates are clipped on to electrically insulated members 13 mounted within the cathode ray tube.
  • a portion of the cathode 15 is shown to indicate the relative position of the deflecting plates with respect to the other parts of the cathode ray tube.
  • Unsymmetrical deflection systems present an additional deflection distortion problem due to a residual astigmatism resulting from a eld distortion.
  • the field distortion in the non-symmetrical deflection system is produced by electrodes arranged near the outlet edges of the defiecting plates which are at the potential of the anode in the cathode ray tube.
  • the electron beam cross-section forms an ellipse due to the action of the positive deflection plate.
  • ellipse is perpendicular to the direction of the deflection.
  • Thisdistortion of the beam can be compensated by an additional feature of the present invention which includes increasing the field intensity in a direction perpendicular to the deflection plane of the electron beam at the outlet edges of the plates.
  • This eld intensity increase is accomplished by removing a portion of the deflection plates at the center of the outlet edge thereof.
  • the arcuate notch 7 indicates the area where a portion of the material has been removed.
  • an electrostatic deflection system for a cathode ray tube; a pair of detlecting plates between which the electron beam passes in direction from the inlet edges to the outlet edges of said plates, said plates having a first zone spaced from the inlet edges thereof wherein said plates are substantially planar and equidistant from the electron beam; and means combined with said deflecting plates for establishing between said first zone and said inlet edges a second zone in which the electric field varies in intensity in a direction transverse to the direction of the plane of deflection of said electron beam.
  • a pair of deflecting plates between which the electron beam passes in direction from the inlet edges to the outlet edges of said plates, said plates having a first zone spaced from the inlet edges thereof wherein said plates are substantially planar and equidistant from the electron beam, the outlet edge of each of said plates including an arcuate shaped portion symmetrically spaced with respect to the electron beam; and means combined with said dellecting plates for establishing between said rst zone and said inlet edges a second zone in which the electric field varies in intensity in a direction transverse to the direction of the plane of'deflection of said electron beam.
  • a pair of deflecting plates between which the electron beam passes in direction from the inlet edges to the outlet edges of said plates; a channel cut in each of said plates between the inlet and the outlet edges thereof so as to form between said plates spaced from the outlet edges of said plates a zone in which the electric field decreases in intensity in a direction transverse to the direction of the plane of deflection of said electron beam; and means combined with said deflecting plates for establishing between said zone of varying field intensity and said outlet edges a zone with uniform electric field intensity.
  • Apparatus as claimed in claim 4 with shield members mounted adjacent each of said channels to prevent extraneous fields from affecting the path of the electron beam.
  • an electrostatic defiecting system for cathode ray tubes including a pair of deflecting plates having an inlet and an outlet portion for the electron beam, the improvement which comprises means for establishing a zone of varying eld intensity between said plates spaced from both the inlet and the outlet portions of said plates; and
  • a pair of deflecting plates between which the electron beam passes in direction from the inlet edges to the outlet edges of said plates, said outlet edges of said plates being substantially wider than said inlet edges so as to form between said plates, spaced from the outlet edges of said plates, a zone in which the electric field varies in intensity in a direction transverse to the direction of the plane of deection of said electron beam; and means combined with said deecting plates for establishing between said zone of varying eld intensity and said outlet edges a zone with uniform electric eld intensity.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US444298A 1953-07-18 1954-07-19 Deflection system for cathode ray tubes Expired - Lifetime US2834902A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE328245X 1953-07-18

Publications (1)

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US2834902A true US2834902A (en) 1958-05-13

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US444298A Expired - Lifetime US2834902A (en) 1953-07-18 1954-07-19 Deflection system for cathode ray tubes

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US (1) US2834902A (enrdf_load_stackoverflow)
CH (1) CH328245A (enrdf_load_stackoverflow)
FR (1) FR1103861A (enrdf_load_stackoverflow)
GB (1) GB773368A (enrdf_load_stackoverflow)
NL (2) NL188970B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986668A (en) * 1957-12-23 1961-05-30 Gen Dynamics Corp Cathode ray tube optical system
US3226594A (en) * 1960-07-08 1965-12-28 Joseph W Griffith Electron beam multiplication tube
US3619687A (en) * 1968-04-14 1971-11-09 Sony Corp Color tv tube having curved convergence deflection plates
JPS50123253U (enrdf_load_stackoverflow) * 1974-03-20 1975-10-08

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2103645A (en) * 1932-12-20 1937-12-28 Schlesinger Kurt Braun tube
US2154127A (en) * 1936-07-07 1939-04-11 Radio Patents Corp Electromechanical oscillating device
US2161437A (en) * 1935-09-30 1939-06-06 Rca Corp Cathode ray deflecting electrode
US2170251A (en) * 1933-11-08 1939-08-22 Loewe Opta Gmbh Television tube
US2524606A (en) * 1939-05-26 1950-10-03 Cossor Ltd A C Electron discharge device
US2574975A (en) * 1950-01-17 1951-11-13 Heinz E Kallmann Electron beam deflecting system
US2734147A (en) * 1956-02-07 beckers

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2734147A (en) * 1956-02-07 beckers
US2103645A (en) * 1932-12-20 1937-12-28 Schlesinger Kurt Braun tube
US2170251A (en) * 1933-11-08 1939-08-22 Loewe Opta Gmbh Television tube
US2161437A (en) * 1935-09-30 1939-06-06 Rca Corp Cathode ray deflecting electrode
US2154127A (en) * 1936-07-07 1939-04-11 Radio Patents Corp Electromechanical oscillating device
US2524606A (en) * 1939-05-26 1950-10-03 Cossor Ltd A C Electron discharge device
US2574975A (en) * 1950-01-17 1951-11-13 Heinz E Kallmann Electron beam deflecting system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986668A (en) * 1957-12-23 1961-05-30 Gen Dynamics Corp Cathode ray tube optical system
US3226594A (en) * 1960-07-08 1965-12-28 Joseph W Griffith Electron beam multiplication tube
US3619687A (en) * 1968-04-14 1971-11-09 Sony Corp Color tv tube having curved convergence deflection plates
JPS50123253U (enrdf_load_stackoverflow) * 1974-03-20 1975-10-08

Also Published As

Publication number Publication date
NL98712C (enrdf_load_stackoverflow)
GB773368A (en) 1957-04-24
CH328245A (de) 1958-02-28
NL188970B (nl)
FR1103861A (fr) 1955-11-08

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