DE1144406B - Magnetic deflection arrangement for cathode ray tubes - Google Patents

Description

GERMAN

PATENT OFFICE

T18025 Vmc / 21g

REGISTRATION DAY: MARCH 10, 1960

NOTICE
THE REGISTRATION
ANDOUTPUTE
EDITORIAL: FEBRUARY 28, 1963

The invention relates to a magnetic deflection arrangement for cathode ray tubes, which a A circular ring-shaped yoke made of ferromagnetic material and a saddle-shaped yoke that tightly encloses the beam Deflection coil set for horizontal deflection and a deflection coil set for vertical deflection from continuously wound toroidal coils, whose located on the inside of the yoke ring Winding parts extend over an azimuthal angle which is smaller than 180 °, so that they the longitudinal conductor bundles of the other Ablenlcspulenspulsatzes overlap.

For magnetic deflection of the electron beam from cathode ray tubes for television purposes, deflection arrangements are known in which two diametrically opposite saddle coils with cosine-shaped winding distribution for deflecting the beam in the horizontal direction are arranged within a circular yoke ring made of ferromagnetic material and enclosing the electron beam two continuously wound toroidal coils are used in the vertical direction, which are wound on the yoke ring or pushed onto it. Such a known arrangement is shown in FIG. The neck 1 of a cathode ray tube is enclosed by a circular yoke ring 2 made of ferromagnetic material, on which two diametrically opposite, continuously wound toroidal coils 3 are arranged such that these coils overlap the longitudinal conductor bundles of one saddle coil 4 wound with a cosine-shaped winding distribution. The longitudinal conductor bundles 5 of these saddle coils are shown in section in this arrangement. In this known arrangement, the toroidal coils 3 are either wound beforehand on a straight winding core and then pushed onto the yoke core or wound directly onto the yoke core 2 by means of a winding machine, the advance of the winding machine being selected so that the core is continuously rotated and the wound Wire always runs radially to the center of the circular yoke. With such an arrangement it is also known to wind the toroidal winding in a so-called sawtooth step, the wire being returned to the beginning of the winding after a completed layer. It is also known to make the distribution of the windings of the toroidal coil unevenly in order to change the potential conditions for this coil.
It is also a magnetic deflection system for magnetic deflection assemblies for cathode ray tubes

Applicant:

Telefunken

Patent collecting society m. B. H., Ulm / Danube, Elisabethenstr. 3

Friedrich Kratochvil, Hanover-Ricklingen, has been named as the inventor

Cathode ray tubes known in which the toroidal coil extends along the circumference of the yoke ring extends an azimuthal angle of 180 °, the winding parts located outside the toroidal core extend over a smaller azimuthal angle. With such a long design of the toroidal coil

The result, however, is very large, pillow-shaped raster distortions. It is also known to have short deflection coils on a deflection yoke of relatively large diameter to be arranged with parallel turns. An overlap of coils of different directions of deflection to improve the image quality and to increase the deflection sensitivity is in the known Arrangement not possible.

The invention is based on the object of a deflection arrangement with overlapping saddle-shaped and toroidal deflection coils the sharpness of the displayed image with simple means to improve. This is achieved if, according to the invention, the toroidal coils, which extend over an azimuthal angle extend by less than 180 °, are wound such that the on the outside of the Yoke ring located winding parts extend over a smaller azimuthal angle than that on the Inside of the yoke located winding parts. In a preferred embodiment the winding parts located on the outside of the yoke ring are gathered together by a U-shaped insulating piece.

To explain the invention in more detail, an exemplary embodiment is described below with reference to FIGS. 2 and 3. Fig. 2 shows a yoke ring half 6 on which a toroidal coil 7 is located. This toroidal coil is sized so that its on the outside

309 537/291

of the yoke located coil parts 8 via a Extend substantially smaller azimuthal angle α than those located on the inside of the yoke ring Coil parts. This is achieved in the illustrated embodiment by a U-shaped insulating piece 9, which is located on the outside of the yoke ring between the yoke ring and the winding. In the event that the coil is pushed onto the core, it can be useful on the inside the coil to attach an adhesive strip 10, the end 11 of which is placed around the end faces of the coil will. The legs 12 of the U-shaped insulating piece 9 can be used as handles for moving the toroidal coils be formed along the circumference of the yoke core. This allows z. B. a trapezoidal distortion be balanced or adjusted. After correct setting, the coils can be set, e.g. B. by spraying on plastic.

This measure ensures that the sharpness of the image point displayed on the screen is significantly improved. This will be explained in more detail with reference to the diagrams shown in FIGS. 3 and 4. There, the point sharpness b for the case of a toroidal coil wound according to FIG. 1 and a toroidal coil wound according to the invention is plotted over the vertical and horizontal pincushion distortion. The width of the pixel is understood here under b , which in the most favorable case (pixel in the middle of the screen) is assumed to be 100%. The distance measured at the edge of the image grid from the shape of a rectangle given by the image corners is given as the value for the pincushion distortion. A is the curve for a toroidal coil according to FIG. 1, a curve for the coil according to the invention. With the same point sharpness, the pincushion distortion in the known coil has two to three times the value compared with the coil according to the invention (measured under the same electrical conditions). It has been shown that the point sharpness of the light spot generated by the cathode ray on the luminescent screen results in more favorable values in the case of coils which are recorded in a circle than in the case of coils which are not recorded in the form of a barrel or which are recorded in the form of a barrel. Such circular distortions are, however, not acceptable from the viewer's point of view. A compromise between point sharpness and distortion has therefore always had to be made up to now. As the diagrams shown in FIG. 3 show, the measure described makes it possible to improve the point sharpness without influencing the circular distortion in an unfavorable sense. With such a coil, the compromise between point sharpness and distortion can therefore be made much more favorable. ·

If the toroidal coils are wound in such a way that the turns are all parallel, one can use a Such a coil also simplifies the manufacturing process with an improvement in the point sharpness will. In this case it is possible to wind the coil directly onto the core without doing anything to have to rotate the core to advance.

Claims (5)

PATENT CLAIMS: 1. Magnetic deflection arrangement for cathode ray tubes, in particular for the picture tube of Television receivers that have a circular ring-shaped yoke made of ferromagnetic Material and a saddle-shaped deflection coil set for horizontal deflection and a deflection coil set for vertical deflection made of continuously wound toroidal coils contains, whose winding parts located on the inside of the yoke ring extend over a Extend azimuthal angle, which is less than 180 °, so that they the longitudinal conductor bundle of the other Deflection coil set overlap, characterized in that the toroidal coils are wound in this way are that the winding parts located on the outside of the yoke ring are on a smaller azimuthal angles extend than the winding parts located on the inside of the yoke ring. 2. Magnetic deflection arrangement according to claim 1, characterized in that the ratio the azimuthal angle is less than 1: 2. 3. Magnetic deflection arrangement according to claim 2, characterized in that the turns of the toroidal coils are parallel. 4. Magnetic deflection arrangement according to claim 1, characterized in that between U-shaped insulating pieces are arranged on the outside of the yoke core and the toroidal coils, the outer turns of the coils are located between the legs. 5. Magnetic deflection arrangement according to claim 4, characterized in that the legs designed as handles for moving the toroidal coils along the circumference of the yoke core are. Considered publications: German utility model No. 1768 722; German interpretation document T 11066 VIIIc / 21g (published on June 21, 1956). 1 sheet of drawings © 309 537/291 2.