JPS62115631A - Polarization yoke and method for removing or reducing distortion - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A deflection unit or deflection yoke is attached to the neck of the picture tube and serves to deflect the electron beam emitted by the gun so as to effect a scanning of the inner part of the screen coated with phosphor. has.

Typically, a deflection unit or deflection yoke is made of a pair of coils that generate a system of orthogonal magnetic fields capable of deflecting the electron beam in directions X, Y, K, with axis Z being the axis of the picture tube. . The coils are held in place by a plastic support and assembled with a half ring of ferrite. In a scanning system, coils operating at low frequencies and deflecting in the Y@ line are generally referred to as vertical coils, others as horizontal coils. Horizontal coils are most often saddle shaped, while vertical coils are saddle shaped or semi-togioidal (
In other words, each carcass is wound around a cow coil and connected to each other so as to emit opposing magnetic fluxes.1Usually,
The internal shape of the 7E2ite is of a swirling shape, sometimes with a pole shoe, in which case the windings are placed in the slots, and the whole is called a "stator" deflection unit.

Electron beam-kot'L is received @! Due to tolerances in the cypress construction of the tube, large beams that are off center are brought to the axis of the screen by the action of a pair of diametrically magnetized positioning rings on the electron beam prior to deflection. be honest about it.

By rotating such magnets with respect to each other and in opposition to each other, a vector sum of one magnetic field and a change in the resultant magnetic field are obtained, and thus a radial displacement is obtained, whereas by rotating one ring together, such The displacement becomes angularly oriented. Due to the structural tolerances of the yoke, picture tube and their connection, the geometrical distortions shown (8) can occur (systematically and irregularly) and require interference after deflection. Become. At present, this is achieved by using crowns of small magnets (dipole) that are individually adjustable for mostly local and selective correction of the image contour. These dipoles are generally stepped on radially inclined or axially oriented appendages of the plastic support.

The work must be performed manually and is difficult and laborious.

The purpose of this invention is to overcome these difficulties.

A yoke or deflection unit for a television monitor or the like, with a ferromagnetic support for correcting distortions in the image obtained from a picture tube coupled or to be coupled with the yoke, has a deflection area in the wide part of the yoke. The yoke has a magnetizable support placed around the yoke, the local magnetization of which is achieved for distortion and geometrical corrections.

Said magnetizable support is in practice configured as an annular continuous support with means for its fixed angular positioning. The magnetizable support preferably has a surface f:m having a frustoconical shape, but it can also have a cylindrical shape, generally of constant thickness.

The yoke can also include a magnetizable support placed around the neck of the picture tube, which support can be locally magnetized to influence the beam deflection.

It is also an object of the invention to provide for the elimination or reduction of distortion in a yoke-picture tube group by the use of a yoke or deflection unit as described above.

Starting from a yoke with a demagnetized support, a local magnetization is applied to the support □ in order to have the desired influence on the image to be obtained. Magnetization is carried out by direct control of the generated image, either on a picture tube to be permanently associated with the yoke, or on a sample picture tube. Alternatively, magnetization can also be performed on the yoke according to a predetermined program.

In either case, the magnetization of the magnetizable support can be carried out simultaneously for all the points provided thereon, or it can be carried out one after the other.

Embodiments of the present invention will be described below with reference to the drawings.

In the drawing, l designates a plastic structure for supporting the yoke member, which structure is axially open and shaped to accommodate the picture tube cf:.

O/ of the picture tube C indicates the neck through which the narrowest part of the yoke t passes; 3 indicates one half-ring made of ferrite, around which a vertical half-troid, indicated by S; A coil is wound. Numbers indicate horizontal saddle-shaped coil windings. The code D is the neck of the picture tube C/
The reference numeral 10 indicates a contact group tube, and the reference numeral 1 indicates a clip means for holding the ferrite. Customarily, an auxiliary annular element made of synthetic resin or thermoplastic is fitted around the wide part of the support (plastic structure),
It holds a series of radially inclined appendages 16. This appendage 16 is usually provided to receive a small magnet M for manually compensating the distortions of the yoke, primarily geometrical distortions, due to the operations described above. Here, this attached auxiliary element (annular element) is provided for attaching the necessary items.

According to the invention, between the wide end portion of the plastic support (plastic structure) l and the annular element/da fitted therein, a ring ig of plastic ferrite is adapted to the shape of the picture tube C. It is held in a truncated conical shape, and in this shape, it is located at a substantially circumferential distance from the junction of the cervical CI. The ring IS thereby remains engaged between the body (plastic structure) l and the ring (annular element) /9. Ring 1g can be locally sixized as described in particular below in the standards mentioned above.

The yoke according to the invention can also be used - instead of two adjusting rings suitable for influencing the deflection prior to deflection, a second degaussing ring made of plasticized ferrite or the like is particularly illustrated in FIGS. A ring 20 can be provided, which has the same purpose as conventionally achieved with a knuckle-adjustable ring.

Ring /f (and also ring 20 when present) is magnetized by separate magnetization means that can generate local FgTilization along ring 9 to achieve geometrical correction. Magnetization can be performed simultaneously or sequentially. In particular, the total internal magnetization is 4. The ring (or each ring) engages the structure l in a manner that prevents relative angular changes.

The magnetization process can be carried out when coupling the yoke to the picture tube by means of a suitable magnetization device. The group of yoke and receiver gjIIW is then restrained and stabilized to obtain a yoke-picture tube unit to be marketed.

According to another process, magnetization is achieved on a number of yokes fitted into a reference or sample picture tube;
These yokes are therefore used in a group of picture tubes to which they are to be combined and of which the reference picture tube is a typical example. This procedure allows a certain latitude in the realization of the individual yoke-picture tube unit, although it can accelerate the magnetization process, but with a clear loss of accuracy.

Another magnetization process consists in carrying out the magnetization of the magnetic support fitted in the yoke according to a predetermined plan, without attachment to the picture tube to be associated with the yoke or to a reference picture tube. This method provides a yoke that can compensate for systematic errors in a group of yokes.

In such cases where the yoke is not coupled to a particular picture tube, the resulting product is a pre-compensated yoke with a receiver I#! similar to the reference picture tube. Mounting occurs randomly for tubes and picture tubes similar to picture tubes in which the systematic errors to be corrected by magnetization are predetermined. This type of yoke can be positioned by a Futsu positioning ring attached to the yoke by an extremely simple operation (as is customarily done for overall correction as shown at the beginning), and A small magnet M attached to the appendage 16 can be coupled to a lit-like picture tube by later interfering to provide correction of residual geometrical errors.

When the procedure includes pre-sharpening of the magnetic support attached to the yoke, magnetization can be achieved from the external egg as well as from the internal gJ1, regardless of the presence or absence of a picture tube fitted with the yoke, i.e. if the yoke is actually ring 1g (and possibly ring 20 that is present).
) can be achieved by transparency, as is necessary when achieving magnetization.

The yoke may be of the light saddle/torus type as shown, or may be of the saddle/saddle type or the stator type.

The invention is applicable to both monochromatic picture tubes and, for example, light valve type multicolor picture tubes.

The magnetizing device can be realized by means of a coil or the like to generate the induced pulses, but if a standardized magnetization is to be achieved in the yoke, the device, whether coupled to a picture tube or not, is uniform. One can be made with a static magnetic field formed by a magnet arranged to produce an equal magnetization for all of the magnetic supports of the yoke to be processed, then after being coupled to its own picture tube. Furthermore, the yoke can be corrected using a small magnet M or the like.

The magnetic support (ring) 1g and coO can contain an annular truncated conical shape, as shown in Figures 4 and 5 for support -0, and are made of a ferromagnetic material such as plasticized 7-elite. It can be made with. The shape of the magnetic support is
It can also be different from having a frustoconical shape; for example, this can be realized with a cylindrical shape. The magnetic support also
It can also be realized partially so that it is continuous on average around the yoke or discontinuous to a limited extent.

In either case, the magnetic support is provided with means for constant angular engagement in addition to axially retaining engagement with the turn of the yoke unit, so that the ferromagnetic support and the plastic support Standard jags and catches can be deployed to coordinate between structures/etc.

Since the invention is capable of changes in shape and arrangement without departing from the scope of the underlying concept, the drawings are
Examples of the invention are provided merely to give a practical indication of the invention.

q Simple 'fx explanation of the drawings nail t1 Figure, crow; figure and Figure 3 represent the deflection yoke according to the invention, viewed in the axial direction, the chain tmn of Figure 1;
-n and a view along break #m-m of FIG. 1; , 4 and S are axial views and views along the dashed line ■-■ of FIG.
It is.

In the drawing, 7g is a magnetizable support, 120 is another magnetizable support, C is the support, CI is the neck?
show.

Claims (1)

[Claims] 1. A deflection yoke for a television set, etc., comprising a ferromagnetic support for correcting distortion in an image obtained from a picture tube coupled with or to be coupled to the yoke. characterized in that it has a magnetizable support arranged around the yoke so as to pass through a deflection area in a wide part of the yoke, the local magnetization of which is achieved for correction of distortions, in particular geometric correction. deflection yoke. 2. Deflection yoke according to claim 1, wherein the magnetizable support is configured as an annular continuous support with means for fixed angular positioning. 3. Deflection yoke according to claim 1 or 2, wherein the magnetizable support has a surface with a frustoconical shape. 4. Deflection yoke according to claim 3, wherein the magnetizable support has a constant thickness. 5. Further comprising another magnetizable support placed around the neck of the picture tube, which support can be locally magnetized to influence the beam before deflection. The deflection yoke according to any one of items 1 to 4. 6. A method for eliminating or reducing distortion in a yoke picture tube group with a magnetizable support in the yoke, in which the support in the yoke is first demagnetized and then the desired influence on the image to be obtained is obtained. A method characterized in that a localized magnetization is applied to the support in order to give it. 7. A method according to claim 6, wherein the magnetization is carried out by direct control of the generated image on a picture tube arranged to be in constant association with the yoke. 8. The method of claim 6, wherein magnetization is performed on a sample picture tube. 9. magnetization is carried out on the yoke according to a predetermined program, in particular for the correction of systematic errors;
A method according to claim 6. 10. The method of claim 6, wherein magnetization is performed on all zones simultaneously. 11. Magnetization is performed on different areas in sequence;
A method according to claim 6. 12. The method of claim 6, wherein the sum of the internal magnetizations is zero.