JPH06187923A - Convergence yoke device - Google Patents

Abstract

PURPOSE:To better the convergence compensation sensitivity of a converging yoke device so as to provide the compact and low-cost yoke device by forming even-numbered projection- shaped polar parts in the inner face of a ring-shaped core unit formed out of a magnetic body, and then directly wrapping a converging coil around the core part of the core unit between two adjacent ones each of the polar parts. CONSTITUTION:Four projection-shaped polar parts 12 are formed in a body in the inner face of a cross-sectionally quadrangular ring-shaped core unit 11 formed out of a magnetic body, and then a converging coil 13 is directly wrapped around the recessed part 14 of the core unit 11 between two adjacent ones each of the polar parts 12. The core unit 11 is also formed in such structure as to be divided into two sections by crevices 16 diametrically formed in the two respective polar parts 12, and when a parabolic current is supplied to each of the coils 13, a magnetic field 15 is generated from each of the polar parts 12. This magnetic field 15 can compensate the shape of an electron beam in the neck part of a cathode- ray tube, mounted onto a converging yoke device invented. The convergence compensation sensitivity of the yoke device can thus be improved by about 30% higher than that of a conventional device while the overall length of a deflection yoke can be shortened by about 5mm more than that of the conventional device so as to equalize intensities of the magnetic fields generated in the yoke device of this invention with one another at low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convergence yoke device.

[0002]

2. Description of the Related Art Conventionally, there has been known a color projection device for projecting an image of a monochromatic CRT corresponding to the three primary colors of R, G and B. In this color projection device, a so-called convergence is provided outside the main deflection yoke. A convergence yoke device for correction is used as a sub deflection yoke.

FIG. 2 is an exploded perspective view of a conventional convergence yoke device. FIG. 2A is a perspective view of an annular core portion.
(B) is a perspective view of a winding part.

Convergence coil 3 is provided on a plurality of rectangular columnar pole portions 2 (four poles are shown in the figure) having a quadrangular cross section protruding from the inner surface of an annular core portion 1 having a quadrangular cross section made of a magnetic material shown in FIG. The conventional convergence yoke device is assembled by inserting the bobbins 4 each having a hollow quadrangular cross section, which are wound around the outer circumference.

The convergence yoke device having such a structure is mounted on the neck portion of the CRT, and a magnetic field 5 generated as shown in FIG.
Is supplied to the neck portion of the CRT to perform convergence correction.

[0006]

However, the conventional convergence yoke device having such a structure has the following drawbacks. (1) Since the magnetic field generated only from the end face 6 of each pole portion 2 is used, sufficient convergence correction sensitivity cannot be obtained. (2) Since the bobbin 4 is required to wind the convergence coil 3, the entire convergence yoke device becomes large, and the assembling work becomes complicated, resulting in an increase in man-hours. (3) The convergence correction characteristic varies depending on the insertability when inserting the bobbin 4 into each pole portion 2, that is, the coil positions are not uniform.

The present invention has been made in view of the above points, and an object of the present invention is to provide a convergence yoke device having a good convergence correction sensitivity, a compact size, and a low cost.

[0008]

In order to solve the above problems, the present invention comprises an annular core portion formed of a magnetic material,
An even number of projecting pole portions are formed on the inner surface of the annular core portion, and a convergence coil is wound around a concave portion between the pole portions of the core portion.

Further, the present invention is characterized in that the annular core portion is divided into two in the diametrical direction at the pole portion.

[0010]

Since the convergence coil is wound directly on the portion on the inner surface of the core portion where the protruding pole portion does not exist, the magnetic field is concentratedly generated from the protruding pole portion, and the convergence correction sensitivity is improved. In addition, the internal magnetic field can be made uniform by generating the magnetic field by optimally determining the number and positions of the protrusions.

[0011]

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

FIG. 1 is a perspective view of the convergence yoke device of the present invention.

The convergence yoke device of FIG. 1 includes an annular core portion 11 having a quadrangular cross section, and an even number (at least four) of protruding pole portions 12 integrally formed with the inner surface of the core portion 11. I'm out. The core portion 11 between the pole portions 12 and 12 serves as a concave portion 14, and the convergence coil 13 is directly wound around the concave portion 14. Further, the core portion 11 is configured to be divided into two by a crack 16 formed in the pole portion 12 in the diameter direction.

When a parabolic current is supplied to the convergence coil 13 of the convergence yoke device having the above structure, a magnetic field 15 is generated from the pole portion 12 as shown in the figure. The magnetic field 15 corrects the electron beam shape inside the neck portion of the CRT in which the convergence yoke device is mounted.

In the above embodiment, the pole portion is formed in an arc shape, but other shapes such as a square shape can be adopted.

The above embodiment illustrates a four-pole convergence yoke device having four poles, and the number of poles is at least four and an even number of more poles can be used. As described above, the core portion can be divided into two, if necessary. When the core portion is divided into two, there is an effect that the convergence coil can be easily wound around the core portion.

[0017]

As described above, according to the present invention, an even number of projecting pole portions are formed on the inner surface of an annular core portion formed of a magnetic material, and the core portion between the pole portions is formed. Since the convergence coil is directly wound, the following excellent effects can be obtained. (1) When the present invention is applied to a 4-pole convergence yoke device, the convergence correction sensitivity is improved by about 30% as compared with the conventional one. (2) Since the coil bobbin, which was required in the conventional convergence yoke device, is not required in the present invention, the entire convergence yoke device becomes compact, and the total length of the deflection yoke can be shortened by about 5 mm as compared with the conventional one. (3) Therefore, it is possible to improve the efficiency of the focus coil by bringing the focus coil mounted after the deflection yoke close to the tube surface side. (4) Since the coil bobbin is not used as described above,
The variation in the position when this is inserted is eliminated, and the fluctuation of the convergence characteristic is reduced. (5) The internal magnetic field can be made uniform.

[Brief description of drawings]

FIG. 1 is a perspective view of a convergence yoke device of the present invention.

FIG. 2 is an exploded perspective view of a conventional convergence yoke device, (a) is a perspective view of an annular core portion, and (b) is a perspective view of a winding portion.

[Explanation of symbols]

 11 Core Part 12 Pole Part 13 Convergence Coil 14 Recess 15 Magnetic Field 16 Crack

Claims (2)

[Claims] 1. An annular core portion made of a magnetic material is provided, an even number of projecting pole portions are formed on the inner surface of the annular core portion, and a convergence is formed in a recess between the pole portions of the core portion. A convergence yoke device in which a coil is wound. 2. The convergence yoke device according to claim 1, wherein the annular core portion is divided into two in the diametrical direction at the pole portion.