US3614688A - Convergence unit for color television picture tube - Google Patents
Convergence unit for color television picture tube Download PDFInfo
- Publication number
- US3614688A US3614688A US46311A US3614688DA US3614688A US 3614688 A US3614688 A US 3614688A US 46311 A US46311 A US 46311A US 3614688D A US3614688D A US 3614688DA US 3614688 A US3614688 A US 3614688A
- Authority
- US
- United States
- Prior art keywords
- legs
- convergence
- core
- coils
- picture 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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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
- H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
- H01J29/702—Convergence correction arrangements therefor
Definitions
- the illustrated convergence unit comprises three generally triangular cores adapted to be mounted around the neck of a color television picture tube at equal angular intervals.
- Each core comprises two legs directed inwardly toward the central axis of the tube, and crossbar means extending between the outer end portions of the legs.
- the legs and the crossbar means form a triangular shape.
- the legs are positioned substantially along radii which extend outwardly from the central axis.
- Horizontal and vertical convergence coils are mounted on the legs.
- the triangular shape of the cores increases the efficiency of the coils. Moreover, the legs are brought into closer proximity to the three electron beams of the picture tube.
- This invention relates to convergence units adapted to be mounted around the neck of a color television cathode-ray picture tube.
- a picture tube has three electron guns in spaced relation to the axis of the tube.
- the beam of each gun is directed to illuminate phosphor dots of a certain color on the screen of the tube.
- the phosphor dots are usually arranged in arrays for each color.
- the electron beam from each gun passes through an aperture screen or shadow mask which has a single set of holes in the same geometric configuration as each array of dots. When the electron beam travels its intended course, it illuminates only those dots which produce the intended color.
- the electron beams from all three guns are aimed to converge upon the holes in the mask, and thereafter the beams diverge as they pass through the holes and arrive at the screen as three individual beams.
- the beams may be aimed to converge at the center of the mask, but problems arise when the beams are swept from side to side and up and down.
- the convergent point of the beams sweeps in an arc which moves it away from the mask at points other than the center of the mask.
- Convergence coil assemblies or units have been devised and are used to meet this problem.
- the beams must converge on the mask so that all three beams pass through the same hole in the mask at correct angles to strike the corresponding phosphor dots on the screen.
- These'assemblies are known as dynamic convergence units because they correct any variations in the length from the deflection point to the apertured mask, as the beams are deflected from the center to the edges of the mask.
- Prior convergence units have generally utilized a plurality of U-shaped cores having legs with horizontal and vertical convergence coils mounted thereon.
- the coils are energized with horizontal and vertical convergence signals developed by special circuits in the television set. These signals are effective to maintain the convergence of the three beams as they are deflected both horizontally and vertically from the center of the mask.
- One type of convergence unit utilizes three cores and three sets of coils thereon, spaced at equal angular intervals around the axis of the tube so as to be opposite the three electron beams.
- One object of the present invention is to provide a new and improved convergence unit in which the legs of the cores are brought into closer proximity to the electron beams of the picture tube, and in which the convergence coils are enabled to operate with improved efficiency.
- a further object is to provide a convergence unit which is especially well adapted for use with a picture tube having a neck of small diameter.
- a further object is to provide a new and improved convergence unit which is especially well adapted for use with a picture tube in which the electron beams are deflected over an exceptionally wide angle.
- the present invention comprises a convergence unit having a plurality of cores made of a ferrite or other suitable magnetically permeable material, the cores being spaced at angular intervals around the central axis of the picture tube.
- Horizontal and vertical convergence coils are mounted on the cores.
- Each core comprises two legs with inner ends directed toward the central axis.
- the coils are mounted on the legs of the cores.
- Each core has crossbar means extending between the outer end portions of the legs.
- the two legs and the crossbar means of each core form a triangular shape.
- the legs extend generally along radii emanating from the central axis. By virtue of this construction, the legs are brought into closer proximity to the electron beams. Moreover, the coils are enabled to operate with improved efficiency.
- FIGURE is an elevational view, partly in section, of a convergence unit to be described as an illustrative embodiment of the present invention.
- the drawing illustrates a convergence unit 10 adapted to be mounted around the neck of a color television picture tube 12.
- the illustrated tube comprises three electron guns or the like for producing three electron beams, designated B, R and G in the drawing, for the three primary colors, blue, red and green.
- the convergence unit 10 comprises three cores or core units 14, one for each of the electron beams.
- the cores 14 are opposite the corresponding electron beams and thus are spaced at equal angular intervals around the central axis of the picture tube 12. It will be seen that the cores 14 are mounted on frames or brackets 16, adapted to be secured to the picture tube 12 by suitable means, such as the illustrated clamp 18.
- each core 14 is generally triangular in shape.
- each core 14 comprises a pair of legs 20 having their inner ends directed toward the central axis of the tube 12.
- Each core 14 comprises crossbar means 22 extending between the outer ends of the legs 20.
- the cores 14 are made of ferrite, or some other suitable material having a high magnetic permeability, and a low-loss factor.
- Pole shoes 24 are preferably mounted against the ends of the legs 20 so as to spread the magnetic flux over wider areas.
- the pole shoes 24 are also made of ferrite or some other suitable material.
- Horizontal and vertical convergence coils 26 and 28 are mounted on the cores 14. In this case, one horizontal coil 26 and one vertical coil 28 are mounted on each leg 20 of each core 14. However, the number of coils can be varied.
- the coils 26 and 28 are wound on bobbins 30 and 32. In the illustrated construction, the bobbins 30 for horizontal coils 26 are mounted in hollow spaces 34, formed in the bobbins 32 for the vertical coils 28. In this way, it is possible to locate both the horizontal and vertical coils 26 and 28 close to the ends of the legs 20.
- each crossbar means 22 It is preferred to split the crossbar means 22 so as to provide a narrow gap 36 therein. Tape or other nonmagnetic material may be mounted in the gap 36. As illustrated, an adjustable permanent magnet 38 is positioned against each crossbar means 22 so as to bridge the gap 36. By adjusting the position of each permanent magnet 38, the initial magnetic flux in the corresponding core 14 can be changed.
- the permanent magnets 38 are preferably disc shaped and are rotatably mounted on the frames 16 for ease of adjustment.
- each core 14 is preferably formed in two pieces 40, each of which comprises one of the legs 20 and one-half of the crossbar means 22.
- the pieces 40 may be moulded or otherwise formed of ferrite material. The formation of each core 14 in two pieces makes it easy to assemble the cores 14 and the coils 26 and 28.
- the legs 20 extend inwardly from the crossbar means 22, generally along radii emanating from the central axis of the picture tube 12. Due to the triangular shape of the core 14, there is an acute angle between such radii for each pair of legs 20. Moreover, acute angles are formed between the crossbar means 22 and the corresponding legs 20.
- the triangular shape of the cores 14 makes it possible to bring the inner ends of the legs 20 close together so that such ends are in close proximity to the corresponding electron beams. In this way, the efficiency of the convergence coils 26 and 28 is greatly improved. Accordingly, the convergence unit of the present invention is especially well adapted for use with a television picture tube having an exceptionally wide deflection angle.
- the triangular construction of the cores 14 also makes it possible to mount the convergence unit around a picture tube having an exceptionally small neck. With the triangular core construction, it is possible to use convergence coils of adequate size, while complying with very severe space limitations.
- the convergence unit of the present invention is exceptionally compact yet highly efficient in operation.
- a convergence unit for a color television picture tube
- each core unit comprising two legs with inner ends directed toward said central axis
- said coils being mounted on said legs
- each core unit comprising crossbar means extending between the outer end portions of said legs
- said legs and said crossbar means being generally in the form of a triangle.
- each leg and the corresponding crossbar means in which an acute angle is formed between each leg and the corresponding crossbar means.
- said coils comprise at least one horizontal convergence coil and at least one vertical convergence coil on each core unit
- each crossbar means is split to form a gap therein
- an adjustable permanent magnet being mounted across said
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Abstract
Description
Claims (7)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US4631170A | 1970-06-15 | 1970-06-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3614688A true US3614688A (en) | 1971-10-19 |
Family
ID=21942763
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US46311A Expired - Lifetime US3614688A (en) | 1970-06-15 | 1970-06-15 | Convergence unit for color television picture tube |
Country Status (1)
Country | Link |
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US (1) | US3614688A (en) |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2897390A (en) * | 1955-12-23 | 1959-07-28 | Glaser Steers Corp | Magnetic convergence assembly |
US3348177A (en) * | 1965-12-27 | 1967-10-17 | Zenith Radio Corp | Convergence device for color television |
-
1970
- 1970-06-15 US US46311A patent/US3614688A/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2897390A (en) * | 1955-12-23 | 1959-07-28 | Glaser Steers Corp | Magnetic convergence assembly |
US3348177A (en) * | 1965-12-27 | 1967-10-17 | Zenith Radio Corp | Convergence device for color television |
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Legal Events
Date | Code | Title | Description |
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AS | Assignment |
Owner name: TORONTO-DOMINION BANK, THE,STATELESS Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC., (SEE RECORD FOR REMAINING GRANTORS);REEL/FRAME:004829/0701 Effective date: 19871216 Owner name: TORONTO-DOMINION BANK, THE Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC., (SEE RECORD FOR REMAINING GRANTORS);REEL/FRAME:004829/0701 Effective date: 19871216 |
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AS | Assignment |
Owner name: TORONTO-DOMINION BANK, THE Free format text: SECURITY INTEREST;ASSIGNORS:TRACOR, INC.;LITTLEFUSE, INC.;TRACOR AEROSPACE, INC.;AND OTHERS;REEL/FRAME:005234/0127 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVING ASSOCIAT Free format text: SECURITY INTEREST;ASSIGNOR:TORONTO DOMINION BANK, THE,;REEL/FRAME:005284/0163 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNORS:TORONTO-DOMINION BANK;TRACOR, INC.;REEL/FRAME:005224/0276 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC.;REEL/FRAME:005217/0247 Effective date: 19880801 Owner name: BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIA Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR INC.;REEL/FRAME:005217/0224 Effective date: 19880801 Owner name: BANK OF AMERICA AS AGENT Free format text: SECURITY INTEREST;ASSIGNOR:TORONTO-DOMINION BANK, THE;REEL/FRAME:005197/0122 Effective date: 19880801 |
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Owner name: TRACOR, INC. Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION AS COLLATERAL AGENT;REEL/FRAME:005957/0562 Effective date: 19911220 Owner name: TRACOR, INC. Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:BANK OF AMERICA NATIONAL TRUST AND SAVINGS ASSOCIATION AS COLLATERAL AGENT;REEL/FRAME:005957/0542 Effective date: 19911227 Owner name: TRACOR, INC. A DE CORPORATION, TEXAS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:OTC TRACOR, INC., A DE CORPORATION;REEL/FRAME:005955/0348 Effective date: 19911220 Owner name: OTC TRACOR, INC. Free format text: CHANGE OF NAME;ASSIGNOR:TRACOR INC., A CORPORATION OF DE;REEL/FRAME:005955/0323 Effective date: 19911122 Owner name: CONTINENTAL BANK N.A. Free format text: SECURITY INTEREST;ASSIGNOR:TRACOR, INC.;REEL/FRAME:005953/0965 Effective date: 19911227 |
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Owner name: BANKERS TRUST COMPANY, NEW YORK Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TRACOR, INC.;REEL/FRAME:006674/0551 Effective date: 19930825 |
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AS | Assignment |
Owner name: TRACOR, INC., TEXAS Free format text: RELEASE BY SECURED PARTY;ASSIGNOR:CONTINENTAL BANK N.A.;REEL/FRAME:006683/0046 Effective date: 19930825 |