US3512023A - Magnetic apparatus for laterally converging the beams of a triple gun cathode ray tube - Google Patents
Magnetic apparatus for laterally converging the beams of a triple gun cathode ray tube Download PDFInfo
- Publication number
- US3512023A US3512023A US816652A US3512023DA US3512023A US 3512023 A US3512023 A US 3512023A US 816652 A US816652 A US 816652A US 3512023D A US3512023D A US 3512023DA US 3512023 A US3512023 A US 3512023A
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- United States
- Prior art keywords
- magnets
- beams
- along
- cathode ray
- displacement
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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.)
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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
- H01J29/702—Convergence correction arrangements therefor
- H01J29/703—Static convergence systems
Definitions
- five magnets are disposed side by side along a line transverse to the axes of the beams. The fields of the magnets are transverse to such line, and also to the axes.
- the third magnet is opposite the first beam.
- the polarization of the second and fourth magnets is opposite to that of the other magnets.
- the fields of the second and fourth magnets are sufficiently stronger than the fields of the other magnets to predominate in the regions around the second and third beams, while the field of the third magnet predominates in the region around the first beam.
- the magnets displace the first beam in one lateral direction while displacing the second and third beams in the opposite lateral direction.
- the magnets displace the beams along the x-axis while neutralizing any tendency towards displacement along the y-axis.
- the magnets are incorporated into a single magnetic memher which is rod shaped and rotatably adjustable about its own axis.
- This invention relates to an apparatus for laterally converging the three electron beams of a triple gun cathode ray tube, which may be of any known or suitable type adapted to be employed in a color television system.
- the need for such lateral convergence is recognized in the'art relating to color television picture tubes, and various arrangements have been provided by the prior art, as attempts to meet this need.
- the general purpose of the lateral convergence apparatus is to displace one electron beam laterally, relative to the other two beams.
- the blue beam of the color television picture tube is displaced along the x-axis relative to th red and green beams.
- the present invention is an improvement upon the lateral convergence apparatus disclosed in FIGS. 6 and 7 of the U.S. patent to Rennick, No. 3,308,328, issued Mar. 7, 1967.
- the Rennick convergence apparatus utilizes five magnets disposed side by side and preferably combined into a single rod shaped magnetic member mounted opposite the neck of the cathode ray tube.
- the third magnet is opposite one of the beams, usually the blue beam.
- the magnets are spaced along a line transverse to the axes of the beams, and the fields of the magnets are transverse to such line, and also to the axes of the beams.
- the polarization of the second and fourth magnets is opposite to that of the first, third and fifth magnets.
- the Rennick arrangement has the disadvantage that the displacement of the blue beam along the x-axis is accompanied by a smaller displacement of the red and green beams in the same direction along the )x-axis. This displacement of the red and green beams in the same direction as the blue beam makes it more diificult to achieve lateral convergence.
- the principal object of the present invention is to provide an improved arrangement whereby the red and green beams are displaced along the x-axis in a direction opposite to the displacement of the blue beam. This arrangement makes it much easier to attain the lateral convergence of the beams.
- the five magnet arrangement of the Rennick patent is modified and improved by giving the second and fourth magnets substantially greater field strength than the third magnet.
- the second and fourth magnets are also preferably stronger than the first and fifth magnets.
- the mag netic fields of the second and fourth magnets are sufficiently stronger than the fields of the other magnets to predominate in the regions of the red and green beams, while the field of the third magnet predominates in the region of the blue beam.
- FIG. 1 is a diagrammatic cross section showing the lateral convergence apparatus to be described as an embodiment of the present invention.
- FIG. 2 is a cross sectional view showing additional details of the lateral convergence apparatus.
- FIG. 3 is a typical graph showing the field strengths of the five magnets employed in the lateral convergence apparatus.
- FIGS. 1 and 2 illustrate a lateral convergence apparatus 10 adapted to be employed in connection with a triple beam cathode ray tube 12, which may be of the type commonly employed in color television systems.
- the three beams are designated B for blue, R for red and G for green.
- the beams are generated by three electron guns 14B, 14R and 14G, disposed in a triangular or delta arrangement, as clearly shown in FIG. 2.
- the electron guns are suitably supported, as by means of three saddle shaped brackets 16 having their ends secured to insulating supports 18.
- Electron guns 14B, R and G are disposed within the neck portion 20 of the cathode ray tube 12.
- the apparatus 10 utilizes five magnets 2125 disposed side by side, opposite the neck of the cathode ray tube 12.
- the magnets 21-25 are arranged along a line extending transversely to the axes of the electron beams B, R and G. It will be seen that the third magnet 23 is opposite one beam, usually the blue beam B.
- the other magnets 21, 22, 24 and 25 are outboard relative to the third magnet 23.
- the five magnets 21-25 are incorporated into a single magnetic member 26, with five pairs of magnetic poles to produce the five magnets.
- the illustrated magnetic member 26 is in the form of a generally cylindrical rod which is rotatably adjustable about its own axis, so that the effective strength of all the magnets can be changed simultaneously.
- the rod shaped magnetic member 26 is mounted for rotary adjustment in a holder 28 which is suitably secured to the neck 20 of the tube 12, as by means of a spring 30.
- the holder 28 has a bore 32 in which the rod 26 is rotatably adjustable. It is preferred to provide a spring 34 in the holder 28 for frictionally retaining the rod 26. The spring 34 insures that the rod 26 will remain in any adjusted position.
- the north and south poles of the magnets 21-25 are indicated by the letters N and S in FIG. 1. It will be seen that the poles of each magnet are on diametrically opposite sides of the magnetic member or rod 26.
- the sec ond and fourth magnets 22 and 24 are polarized oppositely, relative to the first, third and fifth magnets 21, 23 and 25. Thus, the polarity of the magnets alternates along the sequence of five magnets.
- the strength of the second and fourth magnets 22 and 24 is substantially greater than that of the third magnet 23. Moreover, the second and fourth magnets 22 and 24 are preferably greater strength than the first and fifth magnets 21 and 25.
- the third magnet 23 is relatively close to the first electron beam B. Thus, the field of the third magnet 23 predominates in the region of the beam B.
- the fie ds of these magnets are sufiiciently strong to predominate in the regions of the second and third beams R and G, respectively.
- the field of the third magnet 23 causes displacement of the first beam B in one direction along the x-axis, as indicated by the vector 43 in FIG. 1. Because of the reverse polarity of the second and fourth magnets 22 and 24, the second and third beams R and G are displaced in the opposite direction along the x-axis as indicated by the vectors 42 and 44. The opposite displacement of the red and green beams, relative to that of the blue beam, makes it easier to achieve the desired convergence.
- the arrangement of the five magnets 21-25 is such that there is virtually no displacement of the beams B, R and G along the y-axis. This is illustrated by the magnetic field map which has been superimposed upon FIG. 1. Several lines of force are shown, with appropriate arrows to indicate the direction of the magnetic field. Three boundary lines 52, 53 and 54 are shown along which the y-component H of the magnetic field is zero. The blue beam B is directly on the boundary line 53, while the red and green beams R and G are virtually on'the boundary lines 52 and 54. These boundary lines 52, 53 and 54 extend downwardly from the poles of the magnets 22, 23 and 24.
- FIG. 1 also shows boundary lines 56 and 57 along which the x-component H of the magnetic field is zero.
- the polarity of the x-component changes when these bounlary lines are crossed. It will be observed that the red beam R is on the opposite side of the boundary line 56 from the blue beam B. Similarly, the green beam G is on the opposite side of the boundary line 57 from the blue beam B. i
- the graph of FIG. 3 represents the field strength of the five magnets 21-25. It will be seen that the graph has five peaks 61-65 corresponding to the five magnets 21-25.
- the second and fourth peaks 62 and 64 are substantially higher than the third peak 63, thus indicating the greater strength of the second and fourth magnets 22 and 24.
- the second and fourth peaks 62 and are also higher than thefirst and fifth peaks 61 and 65, so as to'indicate that the second and fourth magnets 22 and 24 are stronger than the first and fifth magnets.
- the third magnet is also appreciab y stronger than the first and fifth magnets, as indicated by the greater height of the third peak 63.
- the lateral displacement of the blue beam B is adjusted by' rotating the magnetic member or rod 26 about its own axis in the holder 28, This adjustment changes the effective field strength of all five magnets 2125.
- the blue beam is displaced in one direction along the x-axis, as indicated by the vector 43 in FIG. 1.
- the red and green beams R and G are displaced in the opposite direction along the x-axis, as indicated by the vectors 42 and 44. This opposite displacement results from the greater strength of the second'and fourth magnets 22 I and 24 so that the fields of these magnets predominate in the regions around the red and green beams R and G. There is no appreciable displacement of the beams along the y-axis.
- the opposite lateral displacement of the red and green beams R and G, relative to the displacement of the blue beam B, is highly advantageous, because the desired convergence of the beams is achieved more easily and with a weaker effective magnetic field. 'It is significantly easier to adjust the beams to the desired convergence with the apparatus of the present invention.
- said apparatus comprising an array of five magnets disposed side by side along a line extending transversely to the axes of'the electron'guns,
- said magnets having fields transverse to said line and also to said axes
- the third of said magnets being centrally disposed opposite one of said beams produced by one of said guns
- the second and fourth of said magnets being polarized oppositely relative to the other magnets, said second and fourth magnets having substantially greater field strength than said third magnet whereby said magnets produce displacement of said one electron beam in one lateral direction while displacing the second and third electron beams in the opposite lateral direction.
- the second and fourth magnets have substantially greater field strength than the first and fifth magnets.
- the first, third and fifth magnets have approximately equal field strength.
- said magnetic member having five pairsof magnetic poles to form said five magnets.
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- Video Image Reproduction Devices For Color Tv Systems (AREA)
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US81665269A | 1969-04-16 | 1969-04-16 |
Publications (1)
Publication Number | Publication Date |
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US3512023A true US3512023A (en) | 1970-05-12 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US816652A Expired - Lifetime US3512023A (en) | 1969-04-16 | 1969-04-16 | Magnetic apparatus for laterally converging the beams of a triple gun cathode ray tube |
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Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3684989A (en) * | 1969-08-15 | 1972-08-15 | Denki Onkyo Co Ltd | Convergence apparatus for use in color television cathode ray tubes |
US3713057A (en) * | 1972-01-14 | 1973-01-23 | Motorola Inc | Apparatus for laterally correcting the position of the blue beam in a crt |
US3781731A (en) * | 1973-03-23 | 1973-12-25 | L Poel | Purity and blue lateral assembly for delta beam type cathode ray tube |
US3942146A (en) * | 1974-11-21 | 1976-03-02 | General Instrument Corporation | Purity adjusting device for slotted mask in-line color picture tubes |
US4618843A (en) * | 1984-11-08 | 1986-10-21 | Sony Corporation | Electron beam deflection yoke |
US4749978A (en) * | 1983-11-17 | 1988-06-07 | Denka Seiyaku Kabushiki Kaisha | Magnet for catching thereon foreign bodies within reticulum or ruminant, and method and instrument for manufacture thereof |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3308328A (en) * | 1964-10-02 | 1967-03-07 | Zenith Radio Corp | Magnetic apparatus for converging the beams of a plural gun cathode ray tube |
-
1969
- 1969-04-16 US US816652A patent/US3512023A/en not_active Expired - Lifetime
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3308328A (en) * | 1964-10-02 | 1967-03-07 | Zenith Radio Corp | Magnetic apparatus for converging the beams of a plural gun cathode ray tube |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3684989A (en) * | 1969-08-15 | 1972-08-15 | Denki Onkyo Co Ltd | Convergence apparatus for use in color television cathode ray tubes |
US3713057A (en) * | 1972-01-14 | 1973-01-23 | Motorola Inc | Apparatus for laterally correcting the position of the blue beam in a crt |
US3781731A (en) * | 1973-03-23 | 1973-12-25 | L Poel | Purity and blue lateral assembly for delta beam type cathode ray tube |
US3942146A (en) * | 1974-11-21 | 1976-03-02 | General Instrument Corporation | Purity adjusting device for slotted mask in-line color picture tubes |
US4749978A (en) * | 1983-11-17 | 1988-06-07 | Denka Seiyaku Kabushiki Kaisha | Magnet for catching thereon foreign bodies within reticulum or ruminant, and method and instrument for manufacture thereof |
US4618843A (en) * | 1984-11-08 | 1986-10-21 | Sony Corporation | Electron beam deflection yoke |
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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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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 |