US3234423A - Cathode-ray tube with combined clamping and shielding means - Google Patents
Cathode-ray tube with combined clamping and shielding means Download PDFInfo
- Publication number
- US3234423A US3234423A US96977A US9697761A US3234423A US 3234423 A US3234423 A US 3234423A US 96977 A US96977 A US 96977A US 9697761 A US9697761 A US 9697761A US 3234423 A US3234423 A US 3234423A
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- US
- United States
- Prior art keywords
- tube
- neck
- cathode
- clamp
- ray tube
- 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
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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
- H01J29/56—Arrangements for controlling cross-section of ray or beam; Arrangements for correcting aberration of beam, e.g. due to lenses
Definitions
- the present invention relates to the correction of distortions of the light spot in a cathode-ray tube, particularly where magnetic beam-deflection means are employed, which means include deflection coils mounted on the neck of the tube.
- One prior-art means for magnetic deflection of an electron beam includes saddle-shaped deflection coils mounted on the neck of the tube. As viewed in a plane including the axis of the tube, the deflection field of such deflection coils follows the contour of a bell-shaped curve, ending substantially at the rear end of the deflection coils.
- the contour of the field does not end at the rear end of the deflection coils but extends far behind the deflection coils.
- this interference field of the toroidal deflection coils is capable of counteracting the centering magnets located behind the deflection yoke and of causing other interference.
- this additional terminal ring is both relatively expensive and also considerably diminishes the amplitude of the deflection field.
- the present improvement provides means for fastening the deflection yoke at its rear end to the neck of the tube, these means comprising a substantially cylindrical clamp of forrornagnetic material shaped and located so as to shield from the deflection field the electrode system, especially the electrostatic focussing electrodes located within the neck of the tube.
- a clamp 4 of ferromagnetic material is arranged on the cylindrical extension 3, which clamp secures the yoke 2 to the tube neck.
- the clamp is tightened by cooperating screws 5 preferably transfixing two bent-up lugs 6.
- the position of the clamp on the cylindrical extension 3 of the deflection yoke can be adjusted axially of the tube to an optimum shielding position with respect to the lens system 7 located within the neck of the tube. shown in the drawing is made relatively short, compared 7
- the clamp m 3 ,234,423 Ice Patented Feb. 8, 1966 with the electrode system but may, if desired be made to extend over the length of the whole system.
- its shape and position over the electron lens system may be varied in such a Way as to achieve an optimum shielding effect.
- this clamp of ferromagnetic material prevents the rearwardly-extending deflection-coil field from disturbing the lens system 7, thereby causing the cathode-ray beam not to undergo pre-deflection while still within the lens.
- a cathode-ray tube arrangement comprising, in combinat-ion:
- a magnetic deflection unit arranged exteriorly of said tube and having a cylindrical extension which is coextensive with a portion of the length of said neck and encompasses the same generally in the region of said electrostatic focussing system within said tube neck;
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- Video Image Reproduction Devices For Color Tv Systems (AREA)
Description
Feb. 8, 1966 SCHUBERT 3,234,423
CATHODE-RAY TUBE WITH COMBINED CLAMPING AND SHIELDING MEANS Filed March 2Q. 1961 I 5 5 I 3 )5 If 'l 7 lk A Jnvenfar:
United States Patent 3,234,423 CATHODE-RAY TUBE WITH COMBINED CLAMPING AND SHIELDING MEANS Rudolf Schubert, Nen-Ulm (Danube), Germany, assignor to Telefunken Aktiengesellschaft, Berlin, Germany Filed Mar. 20, 1961, Ser. No. 96,977 Claims priority, application Germany, Mar. 24, 1960,
18,111 4 Claims. (Cl. 31384) The present invention relates to the correction of distortions of the light spot in a cathode-ray tube, particularly where magnetic beam-deflection means are employed, which means include deflection coils mounted on the neck of the tube.
One prior-art means for magnetic deflection of an electron beam includes saddle-shaped deflection coils mounted on the neck of the tube. As viewed in a plane including the axis of the tube, the deflection field of such deflection coils follows the contour of a bell-shaped curve, ending substantially at the rear end of the deflection coils. However, when using toroidal deflection coils where the neck of the cathode-ray tube is surrounded by an annular yoke of ferromagnetic material on which the toroidal coils are wound, the contour of the field does not end at the rear end of the deflection coils but extends far behind the deflection coils. In some deflection systems, this interference field of the toroidal deflection coils is capable of counteracting the centering magnets located behind the deflection yoke and of causing other interference. In this case it has been the practice to abut the deflection coils on the rear side by a ferromagnetic ring, but this additional terminal ring is both relatively expensive and also considerably diminishes the amplitude of the deflection field.
In shallow cathode-ray tubes wherein the neck of the tube is relatively short so that the cathode-ray gun extends into the field of the deflection system, a distortion is frequently noticed which, during deflection of the beam, makes itself apparent in the form of distortion of the light spot on the picture screen of the cathode-ray tube. The present invention has as its primary object the elimination of this distortion.
The present improvement provides means for fastening the deflection yoke at its rear end to the neck of the tube, these means comprising a substantially cylindrical clamp of forrornagnetic material shaped and located so as to shield from the deflection field the electrode system, especially the electrostatic focussing electrodes located within the neck of the tube.
Additional objects and advantages of the present invention will become apparent upon consideration of the following description when taken in conjunction with the accompanying drawings in which the single figure shows a cathode-ray tube 1 with a deflection coil unit or yoke 2, the latter surrounding the neck and extending throughout part of its length. The deflection yoke is provided at its rear end with a cylindrical extension 3, which serves for fixing the yoke 2 by means of the clamp 4. It may be advantageous to provide slots in axial direction in this cylindrical extension 3 which allow the inner diameter to be varied by driving the screws 5.
A clamp 4 of ferromagnetic material is arranged on the cylindrical extension 3, which clamp secures the yoke 2 to the tube neck. The clamp is tightened by cooperating screws 5 preferably transfixing two bent-up lugs 6. The position of the clamp on the cylindrical extension 3 of the deflection yoke can be adjusted axially of the tube to an optimum shielding position with respect to the lens system 7 located within the neck of the tube. shown in the drawing is made relatively short, compared 7 The clamp m 3 ,234,423 Ice Patented Feb. 8, 1966 with the electrode system, but may, if desired be made to extend over the length of the whole system. Besides the width of the clamp, its shape and position over the electron lens system may be varied in such a Way as to achieve an optimum shielding effect.
The provision of this clamp of ferromagnetic material prevents the rearwardly-extending deflection-coil field from disturbing the lens system 7, thereby causing the cathode-ray beam not to undergo pre-deflection while still within the lens.
It will be understood that the above description of the present invention is susceptible to various modifications, changes, and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
What is claimed is:
1. A cathode-ray tube arrangement comprising, in combinat-ion:
(a) a cathode-ray tube having a neck;
(b) an electrostatic focussing system arranged within said tube neck;
(c) a magnetic deflection unit arranged exteriorly of said tube and having a cylindrical extension which is coextensive with a portion of the length of said neck and encompasses the same generally in the region of said electrostatic focussing system within said tube neck; and
(d) means for both attaching said magnetic deflection unit to said tube and shielding said electrostatic focussing system from the magnetic field of said magnetic deflection unit, said means being constituted by a clamp made of ferromagnetic material which firmly encompasses said extension of said magnetic deflection unit thereby to clamp the same to said neck of the said tube, said clamp having the shape of a cylinder which is coaxial with respect to said neck of said tube and also closely surrounds the same in said region of said electrostatic focussing system, in consequence of which said ferromagnetic clamp serves simultaneously to fasten said magnetic deflection unit to said cathode-ray tube as well as to shield said electrostatic focussing ssytem within said tube neck from the magnetic field of said magnetic deflection unit, thereby to prevent distortions of the light spot in the cathode-ray tube which would otherwise be caused by the effect of the magnetic field on said electrostatic focussing system.
2. The arrangement defined in claim 1 wherein said extension is yieldable.
3. The arrangement defined in claim 2 wherein the yieldability of said extension is obtained by the fact that said extension is provided with axially extending slots which allow the diameter of said extension to be varied.
4. The arrangement defined in claim 1 wherein the axial dimension of said extension is greater than that of said clamp, in consequence of which said clamp is displaceable on and with respect to said extension in the direction of the axis of the tube neck.
References Cited by the Examiner UNITED STATES PATENTS 2,717,324 9/1955 Hall 31394 2,830,213 4/1958 Leeds 313-846 2,889,477 6/1959 King et al 313-84.6 2,907,914 10/1959 Brownell 3158 2,922,908 1/1960 Heller 31376 X ROBERT SEGAL, Acting Primary Examiner.
RALPH G. NILSON, DAVID J. GALVIN, GEORGE N. VJESTBY, Examiners.
Claims (1)
1. A CATHODE-RAY TUBE ARRANGEMENT COMPRISING, IN COMBINATION: (A) A CATHODE-RAY TUBE HAVING A NECK; (B) AN ELECTROSTATIC FOCUSSING SYSTEM ARRANGED WITHIN SAID TUBE NECK; (C) A MAGNETIC DEFLECTION UNIT ARRANGED EXTERIORLY OF SAID TUBE AND HAVING A CYLINDRICAL EXTENSION WHICH IS COEXTENSIVE WITH A PORTION OF THE LENGTH OF SAID NECK AND ENCOMPASSES THE SAME GENERALLY IN THE REGION OF SAID ELECTROSTATIC FOCUSSING SYSTEM WITHIN SAID TUBE NECK; AND (D) MEANS FOR BOTH ATTACHING SAID MAGNETIC DEFLECTION UNIT TO SAID TUBE AND SHIELDING SAID ELECTROSTATIC FOCUSSING SYSTEM FROM THE MAGNETIC FIELD OF SAID MAGNETIC DEFLECTION UNIT, SAID MEANS BEING CONSTITUTED BY A CLAMP MADE OF FERROMAGNETIC MATERIAL WHICH FIRMLY ENCOMPASSES SAID EXTENSION OF SAID MAGNETIC DEFLECTION UNIT THEREBY TO CLAMP THE SAME TO SAID NECK TO THE SAID TUBE, SAID CLAMP HAVING THE SHAPE OF A CYLINDER WHICH IS COAXIAL WITH RESPECT TO SAID NECK OF SAID TUBE AND ALSO CLOSELY SURROUNDS THE SAME IN SAID REGION OF SAID ELECTROSTATIC FOCUSSING SYSTEM, IN CONSEQUENCE OF WHICH SAID FERROMAGNETIC CLAMP SERVES SIMULTANEOUSLY TO FASTEN SAID MAGNETIC DEFLECTION UNIT TO SAID CATHODE-RAY TUBE AS WELL AS TO SHIELD SAID ELECTROSTATIC FOCUSSING SYSTEM WITHIN SAID TUBE NECK FROM THE MAGNETIC FIELD OF SAID MAGNETIC DEFLECTION UNIT, THEREBY TO PREVENT DISTORTIONS OF THE LIGHT SPOT IN THE CATHODE-RAY TUBE WHICH WOULD OTHERWISE BE CAUSED BY THE EFFECT OF THE MAGNETIC FIELD ON SAID ELECTROSTATIC FOCUSSING SYSTEM.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DET18111A DE1144407B (en) | 1960-03-24 | 1960-03-24 | Device to avoid distortion of the light spot in cathode ray tubes |
Publications (1)
Publication Number | Publication Date |
---|---|
US3234423A true US3234423A (en) | 1966-02-08 |
Family
ID=7548826
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US96977A Expired - Lifetime US3234423A (en) | 1960-03-24 | 1961-03-20 | Cathode-ray tube with combined clamping and shielding means |
Country Status (4)
Country | Link |
---|---|
US (1) | US3234423A (en) |
BE (1) | BE601634A (en) |
DE (1) | DE1144407B (en) |
GB (1) | GB977465A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3831051A (en) * | 1968-10-09 | 1974-08-20 | Sony Corp | Color picture tube with deflection center control |
DE3128299A1 (en) * | 1981-07-17 | 1983-06-09 | Videocolor S.A., 92128 Montrouge | Beam generator system of a television tube or the like |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2717324A (en) * | 1950-05-04 | 1955-09-06 | Emi Ltd | Cathode ray tubes |
US2830213A (en) * | 1955-09-08 | 1958-04-08 | Gen Electric | Deflection coil |
US2889477A (en) * | 1955-06-16 | 1959-06-02 | Sylvania Electric Prod | Clamp and mounting arrangement |
US2907914A (en) * | 1954-05-26 | 1959-10-06 | Magnetic Metals Company | Electrically energized magnetic shield |
US2922908A (en) * | 1955-08-31 | 1960-01-26 | Westinghouse Electric Corp | Retaining device |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2926272A (en) * | 1958-06-24 | 1960-02-23 | Philco Corp | Combined shielding and centering means for cathode ray tubes |
-
1960
- 1960-03-24 DE DET18111A patent/DE1144407B/en active Pending
-
1961
- 1961-03-20 US US96977A patent/US3234423A/en not_active Expired - Lifetime
- 1961-03-22 BE BE601634A patent/BE601634A/en unknown
- 1961-03-24 GB GB10862/61A patent/GB977465A/en not_active Expired
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2717324A (en) * | 1950-05-04 | 1955-09-06 | Emi Ltd | Cathode ray tubes |
US2907914A (en) * | 1954-05-26 | 1959-10-06 | Magnetic Metals Company | Electrically energized magnetic shield |
US2889477A (en) * | 1955-06-16 | 1959-06-02 | Sylvania Electric Prod | Clamp and mounting arrangement |
US2922908A (en) * | 1955-08-31 | 1960-01-26 | Westinghouse Electric Corp | Retaining device |
US2830213A (en) * | 1955-09-08 | 1958-04-08 | Gen Electric | Deflection coil |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3831051A (en) * | 1968-10-09 | 1974-08-20 | Sony Corp | Color picture tube with deflection center control |
DE3128299A1 (en) * | 1981-07-17 | 1983-06-09 | Videocolor S.A., 92128 Montrouge | Beam generator system of a television tube or the like |
Also Published As
Publication number | Publication date |
---|---|
DE1144407B (en) | 1963-02-28 |
BE601634A (en) | 1961-07-17 |
GB977465A (en) | 1964-12-09 |
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