US3701067A

US3701067A - Saturable reactor

Info

Publication number: US3701067A
Application number: US221742*A
Authority: US
Inventors: Shuzo Tsubakihara
Original assignee: Denki Onkyo Co Ltd
Current assignee: Denki Onkyo Co Ltd
Priority date: 1971-01-28
Filing date: 1972-01-28
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24
Also published as: JPS533689Y2; DE2203777C3; DE2203777B2; DE2203777A1; JPS472448U

Abstract

A saturable reactor including a pair of bar type cores which are respectively provided with a primary coil and a secondary coil and are arranged in parallel and a pair of magnets which are provided respectively at both ends of the cores and are arranged to contact the ends of both cores at the same time. The magnets have opposed magnetic poles of different polarity so that a biased magnetic flux flows in the cores. The primary coils are arranged so that primary magnetic fluxes are generated in the same direction with reference to the direction of the biased magnetic flux while the secondary coils are arranged so that secondary magnetic fluxes are generated in the opposite direction to each other in reference to the direction of the biased magnetic flux.

Description

United States Patent 1151 3,701,067

Tsuhakihara Oct. 24, 1972 [$4] SATURABLE REACTOR 2,040,768 5/1936 Edwards "336/1 10 X t I h 2,802,170 8/1957 Starr et al. ..336/110 x m] 1;: Twmhm Kanagawa' 2,860,313 11/1953 Israel ..336/110 ['73] Assignee: Denki Onkyo Co., Ltd., Tokyo, Primary ExamingrThomas J. Kozma Japan Attorney-James E. Armstrong et al.

[22] Filed: Jan. 28, 1972 1211 Appl. No.: 221,142

[57] ABSTRACT A saturable reactor including a pair of bar type cores which are respectively provided with a primary coil and a secondary coil and are arranged in parallel and a pair of magnets which are provided respectively at both ends of the cores and are arranged to contact the ends of both cores at the same time. The magnets have opposed magnetic poles of different polarity so that a biased magnetic flux flows in the cores. The primary coils are arranged so that primary magnetic fluxes are generated in the same direction with reference to the direction of the biased magnetic flux while the secondary coils are arranged so that secondary magnetic fluxes are generated in the opposite direction to each other in reference to the direction of the biased magnetic flux.

9 Claims, 5 Drawing figures [30] Foreign Application Priorlty Data Jan. 28, 1971 Japan ..46/3795 [521 11.8. CI. ..336/90, 336/110, 336/132, 336/155 [51] Int. Cl .1101! 21/00 [58] Field of Search ..336/110, 132, 90, 155

[56] References Cited UNITED STATES PATENTS 3,157,848 11/1964 Boiten ..336/110 3,390,364 6/1968 Russell ..336/1 10 2,218,711 10/1940 Hubbard ..336/110 X I '1 l/l/l f I i 15 [ll/ll ljl/l 1 SATURABLE REACTOR BACKGROUND OF THE INVENTION The present invention relates to a reactor for controlling or modifying pincushion" type distortion in cathode ray tube displays. it is particularly well suited for use in conjunction with color display tubes.

Pincushion type distortion of cathode ray tube displays has long been recognized. ln black-and-white displays, this type of distortion is corrected to a considerable extent through the use of permanent magnets, which are so shaped and fixed in positions relative to the cathode as to produce an appropriate magnetic biasing effect on the cathode ray beam. In the case of color display tubes, which are based on the use of shadow mask or similar principles, however, fixed correcting magnets cannot be used.

One approach, which has been adopted in connection with the correction of pincushion distortion in color displays involves the modulation or variation of one of the sweep currents in such a manner as to produce the desired results.

In the arrangement for correction of raster distortion occurring in the vertical direction (e.g., top and bottom pincushion distortion), the cyclically varying vertical scanning current must be modulated at a higher horizontal rate, such as by adding a horizontal rate correction current alternated parabolically to the vertical deflection current.

ln the arrangement for the correction of raster distortion occurring in the horizontal direction (e.g., side pincushion distortion), the cyclically varying horizontal scanning must be varied at a lower vertical rate, since the magnitude of a horizontal scanning current is parabolical.

It has further been suggested in the prior art that this modulation be accomplished eiectromagnetically using a combination of magnetic and electrical circuitry which works on the principle of magnetic saturability.

In general, nominal correction can be produced by this means. There are many kinds of saturable reactor device and circuit connections for correcting pincushion distortion such as those described in U.S. Pats, No. 2,906,919, No. 3,346,765, and No. 3,444,422.

The existing reactor, as seen in the aforementioned U.S. patents, is composed of a core that mutually couples the two ends of three parallel yokes, a coil shuntwound on the two yokes on both sides of the core in opposite winding directions and is connected in series, and another coil wound on the center of the core. Since the vertical deflection current has been applied to one of the above-mentioned coils and the horizontal deflection current has been applied to the other coil, the device has disadvantages as described herein.

In the manufacture of a reactor, coils arefitted to respective yokes of an E-shaped core, and l-shaped core is coupled on the free ends of the yokes of the E- shaped core in order to magnetically couple the yokes. Using this process, the manufacturing process has been time consuming, making it unsuited to mass-production. Magnetic flux leakage has been small, since the yokes formed a closed magnetic path. However, since current magnetic flux density in the closed magnetic path varied markedly depending on the infinitesimal differences in the gaps in the magnetic path, the characteristics of individual products lost uniformity because of disparity in the gap arising in the coupled part of the E-shaped core and the I-shaped core.

Therefore, as described in U.S. Pat. No. 3,571,606, a saturable reactor comprised of one bar type core provided with four coils has been recently offered. However, it is disadvantageous because this type of the saturable reactor has a long bar type core and handling is difficult, for example, when attaching the reactor directly to a deflection yoke.

The present invention provides a saturable reactor which is extremely easily assembled to be compact and manufactured to have uniform quality.

SUMMARY The present invention provides a saturable reactor comprised of a pair of bar type cores provided with primary coils and secondary coils and arranged in parallel and a pair of magnets which have opposed magnetic poles with different polarity to supply a biased magnetic flux to the cores and are mounted so that the magnetic poles contact the ends of said cores at the same time, wherein a pair of said primary coils which are wound on a pair of cores generate both magnetic fluxes in the same direction in reference to the direction of the biased magnetic flux and a pair of secondary coils which are wound on a pair of cores generate the magnetic fluxes in opposite directions to each other in reference to the direction of said biased magnetic flux.

BRIEF DESCRIPTION OF THE INVENTION The present invention is illustrated in detail by the accompanying drawings whereon:

FIG, 1 is a cross sectional front view of important parts of a saturable reactor according to the present invention,

FIG. 2 is a side view of a saturable reactor according to the present invention,

' FIG. 3 is a cross sectional front view of important parts of said saturable reactor showing another embodiment,

FIG. 4 is a side view of the saturable reactor shown in FIG. 3, and

FIG. 5 is a side view of the saturable reactor illustrating another embodiment of the present invention.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2, there is shown a saturable reactor comprised of a pair of bar type cores 1 and l which are arranged in parallel, a pair of primary coils 2 and 2' which are wound on said cores respectively, a pair of

secondary coils

3 and 3 which are wound on said cores respectively and a pair of magnets 4 and 4' which have opposed magnetic poles with different polarities to supply the biased magnetic flux f to the cores and are provided at both ends of a pair of cores. Said reactor is housed in a suitable supporting member, for example, case 5.

Said primary coils 2 and 2' are wound so as to generate both magnetic fluxes in the same direction in reference to the direction of the biased magnetic flux. The magnetic flux are applied in the same direction as or the reverse direction to the biased magnetic flux at the same time according to the direction of the deflection current as known from the prior art.

In other words, the primary coils are wound such that when the flux of the first primary coil is in the same direction as the biased magnetic flux of its core, the flux of the second primary coil is in the same direction as the biased magnetic flux of its core and, conversely, when the flux of the first primary coil is in the opposite direction as the biased magnetic flux of its core, the flux of the second primary coil is also in the opposite direction as the biased magnetic flux of its core.

A pair of said

secondary coils

3 and 3 are wound so as to generate the magnetic fluxes in the opposite direction to each other in reference to the direction of the biased magnetic flux. The direction of the generated magnetic fluxes is reversed in accordance with the direction of the deflection current as known from the prior art.

In other words, the secondary coils are wound such that when the flux of the first secondary coil is in the same direction as the biased magnetic flux of its core, the flux of the second secondary coil is in the opposite direction as the biased magnetic flux of its core and, conversely, when the flux of the first secondary coil is in the opposite direction as the biased magnetic flux of its core, the flux of the second secondary coil is in the same direction as the biased magnetic flux of its core.

When compensating the pincushion distortion appearing at the top and bottom of the raster, the primary coils are series-connected to the horizontal deflection current source and the secondary coils are series-connected to the vertical deflection current source.

However, the power supplies to which the primary coils and secondary coils are to be connected and the method of connection can be determined according to the purpose as known technically.

According to this embodiment, the saturable reactor is advantageous because the bar type core can be shortened thereby reducing length l of the entire reactor. It is also advantageous because one primary coil and one secondary coil can be wound on each core permitting improved production efficiency by divided work. Furthermore, the winding is made easy and the material cost reduced because a short core can be used.

In this embodiment, magnets 4 and 4' are fixed to the cores and are magnetized so that magnetic poles N and S are at both ends in the lengthwise direction.

However, magnets 4 and 4' can be energized in the direction of thickness as shown in FIGS. 3 and 4 and at least one of the magnets can be disc type magnet 4, having a flux varying at a given radius from one radial to another, which is rotatable at support shaft 41 provided at the center of the magnet.

If the saturable reactor is thus formed, the magnetizing bias of the cores can be adjusted because the amount of the biased magnetic flux can be changed as disc-type magnet 4 is rotated. If the magnet is made to be of the rotary type, it is desirable to fonn a knurled surface 42 on the magnet as shown in FIG. 4, thus smoothing rotation of the magnet. The magnetizing bias of the core can be changed by rotating the disctype magnet which is energized in the radial direction. If one or all magnets are made to be movable magnet 4, the magnets can be moved in the radial direction by attracting the magnets to the ends of a pair of cores as shown in FIG. 5. In this case, it is desirable to use the magnet energized in the radial direction. The magnetizing bias of a pair of cores 1 and 1' can be changed to the same degree or the magnetizing bias of a pair of cores can be set to different values. For example, in FIG. 5, the magnetizing bias of core 1 can be reduced by shifting magnetic pole S without shifting magnetic pole N.

As known from the above, it is effective for adjusting the magnetizing bias to make a pair of

magnets

4 and 4 the movable type magnet.

The winding direction of said primary and secondary coils in the embodiment of FIG. 1 is different from that in the embodiment in FIG. 3. The winding direction of these coils is detemrined according to the direction of biased magnetic flux f.

The primary coils of the saturable reactor shown in FIG. I are wound in the same direction and the secondary coils are wound in opposite directions, whereas the primary coils of the saturable reactor shown in FIG. 3 are wound in opposite directions and the secondary coils are wound in the same direction.

The saturable reactor according to the present invention is as described above. It can provide great advantages in employment in the cathode ray tubes for television sets for which the demand is increasing more and more.

Whatl claim is:

l. A saturable reactor comprised of a. a pair of bar type cores arranged in parallel,

b. a pair of magnets having opposed magnetic poles with diflerent polarity which contact both ends of each of said pair of cores at the same time, said magnets being adapted to supply a biased mag netic flux to each of said cores,

c. primary coils wound on each of said cores which are arranged to generate magnetic fluxes in the same direction with reference to the direction of said biased magnetic flux, and

. secondary coils wound on each of said cores which are arranged to generate magnetic fluxes in opposite directions to each other with reference to the direction of said biased magnetic flux.

2. A saturable reactor according to claim 1, wherein at least one of said magnets is rotatable.

3. A saturable reactor according to claim 2, wherein a knurled surface is formed on the external surface of a rotatable magnet.

4. A saturable reactor according to claim I, wherein at least one of said magnets is arranged so as to be shifted in its radial direction.

5. A saturable reactor according to claim I, wherein said primary coils are wound directly on said cores and said secondary coils are wound on said primary coils.

6. A saturable reactor according to claim 1, wherein said primary and secondary coils are all wound directly on said cores.

7. A saturable reactor according to claim 1, wherein the biased magnetic fluxes of each of said cores are in the same direction.

8. A saturable reactor according to claim 1, wherein the biased magnetic fluxes of each of said cores are in opposite directions.

9. A saturable reactor according to claim 1, further comprising a case means for containing the remainder of said saturable reactor.

Claims

1. A saturable reactor comprised of a. a pair of bar type cores arranged in parallel, b. a pair of magnets having opposed magnetic poles with different polarity which contact both ends of each of said pair of cores at the same time, said magnets being adapted to supply a biased magnetic flux to each of said cores, c. primary coils wound on each of said cores which are arranged to generate magnetic fluxes in the same direction with reference to the direction of said biased magnetic flux, and d. secondary coils wound on each of said cores which are arranged to generate magnetic fluxes in opposite directions to each other with reference to the direction of said biased magnetic flux.

4. A saturable reactor according to claim 1, wherein at least one of said magnets is arranged so as to be shifted in its radial direction.

5. A saturable reactor according to claim 1, wherein said primary coils are wound directly on said cores and said secondary coils are wound on said primary coils.