JPH0963512A - Deflection yoke and convergence correcting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance image quality by correcting mis-convergence corresponding to not only the front part of a deflecting yoke but also all parts, particularly, the mis-convergence of a green beam. SOLUTION: A gap between the funnel part 2 of a cathode-ray tube A and a deflecting yoke 3 is formed in both front and rear parts of the deflection yoke 3. Mis-convergence is corrected by making it feasible to insert a convergence correcting ferrite sheet 8 in both directions to enhance image qualily.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke in which a ferrite for convergence correction is externally fitted to a cathode ray tube and a method for correcting convergence using the deflection yoke.

[0002]

2. Description of the Related Art As shown in FIG. 4, in a color cathode ray tube, in order to deflect three electron beams emitted from three electron guns by applying vertical and horizontal forces by a magnetic field,
A deflection yoke 30 is externally fitted to an outer portion near the boundary between the neck portion 10 and the funnel portion 20 of the color cathode-ray tube A, and the three electron beams are designed so as to be exactly on the fluorescent screen and are wedge-shaped. It is fixed with a seat 50. However, it may shift due to variations in parts and variations in assembly. Concentration of three electron beams at one point on the shadow mask surface of the color cathode ray tube is called convergence, and the deviation is called misconvergence.
When the horizontal deflection magnetic field of the deflection yoke 30 has a certain inclination with respect to the horizontal axis, or when the center electron beam G is displaced upward or downward with respect to the electron beams R and B on both sides. Misconvergence occurs. In addition, if the convergence is not completely obtained, a color image having a color misregistration such as a primary color plate printing with poor superposition is obtained.

Such misconvergence is a problem in general TVs, but it is a particularly troublesome problem in color cathode ray tubes used for high-definition display monitors. Therefore, the deflection yoke 30
The small plate-shaped magnetic pieces 40a to 40d as shown in FIG. 5 are fixed to the bobbin or the coil itself of FIG. 5 by an adhesive or a double-sided adhesive tape on the inner surface 30a side of the deflection yoke 30, or as shown in FIG. It is a practical example that the convergence correcting ferrite sheet 8 having the magnetic material 8b fixed to one end of the elongated non-magnetic material 8a is inserted between the deflection yoke 30 and the funnel 20 and fixed by the adhesive or the double-sided tape 8c.
No. 8-7965. However, when the magnetic pieces 40a to 40d are directly attached to the inner surface of the deflection yoke 30, there is a problem that fine adjustment cannot be performed when the product is completed, and the elongated ferrite sheet 8 of about 3 mm width × 100 mm is used as the deflection yoke 30. With the one that is inserted between the funnel 20 and fixed with the adhesive or the double-sided adhesive tape 8c, fine adjustment can be made to some extent, but the correction ferrite sheet 8 is inserted in a narrow gap as shown in FIG. Therefore, the adjustment range is limited because it only faces in the tube axis direction along the funnel 20.

[0004]

When the latter method is adopted, the convergence correction ferrite sheet 8 cannot be placed too deeply by the adjustment only from the front side of the deflection yoke 30, that is, the phosphor screen side, and the deflection yoke 30 is prevented. There is a problem that only the misconvergence corresponding to the front part 31 of the can be corrected. In particular, since the green convergence is determined by the relative relationship between the electron beams corresponding to red and blue, it is almost impossible to adjust from the front direction. The present invention has been made in view of such a situation, and fine adjustment of misconvergence can be performed from either the front portion 31 or the rear portion 32 of the deflection yoke 30, and the misconvergence corresponding to the entire deflection yoke 30, particularly the green. It is intended to allow the correction of convergence.

[0005]

A deflection yoke for adjusting misconvergence by inserting a ferrite sheet for correcting convergence into a gap formed by being externally fitted to a funnel portion of a cathode ray tube, the ferrite sheet for correcting from both front and rear directions. There is provided a deflection yoke in which the gap is formed so as to allow the insertion. Also, a gap between the retaining ring of the deflection yoke and the coil bobbin is secured by a separator, and this gap is set to 0.5.
A deflection yoke having a size of mm to 2 mm is provided. Further, there is provided a convergence correction method in which a correction ferrite sheet is inserted from both front and rear directions, and the correction ferrite sheet inserted through the gap in the rear portion is swung to correct the misconvergence.

[0006]

[Function] The distance between the funnel portion of the cathode ray tube and the deflection yoke is widened not only in the front portion but also in the rear neck side, and the ferrite sheet for convergence correction can be inserted from the rear side. You can fix the convergence, especially the green misconvergence. Further, by connecting the expanded coil bobbin and the stop ring with a separator, the deflection yoke can be fixed to the neck in the same manner as in the conventional case.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a front view showing the essential structure of a color cathode ray tube which is an embodiment of the present invention. This color cathode ray tube A is composed of a panel portion 4, a funnel portion 2 and a neck portion 1, and an in-line type electron gun (not shown) which emits three electron beams passing through the same plane in the neck portion 1 of the funnel portion 2. Is provided, and a deflection yoke 3 including a pair of horizontal deflection coils and vertical deflection coils is disposed outside the funnel portion 2 at a predetermined position. That is, the deflection yoke 3 is fixed by inserting a plurality of wedge-shaped seats 5 made of a rubber-like elastic body between the fluorescent screen side end (front end) and the outside of the funnel part 2. The convergence correcting ferrite sheet 8 can be inserted from between the seat 5 and the misconvergence mainly concerning the electron beams R and B on both sides can be corrected. This part is no different from the conventional example. The other end (rear end) on the side of the electron gun is an iron stop ring 6 for fixing the deflection yoke. The neck 1 is provided with plastic or cloth tape (not shown) to prevent cracking of the neck 1. , And the deflection yoke 3 is attached at a predetermined position in an adjusted state. In this way, the stop ring 6 at the rear end is connected to the coil bobbin 9 with a gap of 0.5 mm to 2 mm from the neck 1 by the separator 7, and the ferrite sheet 8 for correction is also inserted from this direction. Mainly, the misconvergence related to the electron beam G of the center can be corrected. This gap is preferably as narrow as possible in relation to the deflection sensitivity, but a gap in which the correction ferrite sheet 8 having a thickness of a polyester film sheet coated with a magnetic material can be inserted is necessary. According to the mounting structure of the deflection yoke 3 described above, the gap between the deflection yoke 3 and the neck portion 1 can be arbitrarily set by the length dimension of the separator 7 of the stop ring 6, so that the rear portion of the deflection yoke 3 is larger than the rear portion. The correction ferrite sheet 8 to be inserted can be moved not only in the front-rear direction but also in a swinging motion, so that a more accurate convergence correction method can be obtained.

Further, FIG. 3 shows that the notch 6a for inserting the correction ferrite sheet 8 is provided on the inner peripheral surface of the stop ring 6 without using the separator 7 described above.

Although the color cathode ray tube having the in-line type electron gun which emits three electron beams passing through the same plane has been described above, the present invention can be applied to the color cathode ray tube having the delta type electron gun.

[0010]

By forming a gap between the funnel portion of the cathode ray tube and the deflection yoke so that the convergence correcting ferrite sheet can be inserted from the front-rear direction, only from the front portion of the deflection yoke as in the prior art. It is possible to correct not only the misconvergence corresponding to the magnetic field of, but also the misconvergence corresponding to all positions, especially the green misconvergence, and it is possible to provide a color cathode ray tube having a good characteristic with no deviation in convergence.

[Brief description of drawings]

FIG. 1 is a front view showing a configuration of a color cathode ray tube in which a convergence correcting ferrite sheet according to the present invention is inserted from front and rear portions.

FIG. 2 is an enlarged view of a retaining ring portion of a deflection yoke when FIG. 1 is viewed from the rear.

FIG. 3 Enlarged view of different retaining rings

FIG. 4 is a front view showing a configuration in which a convergence correction ferrite sheet is inserted from the front into a conventional color cathode ray tube.

FIG. 5 is a plan view of a deflection yoke with a magnetic piece attached, as seen from the front.

FIG. 6 is a plan view of a ferrite sheet for correcting convergence.

[Explanation of symbols]

 1 neck part 2 funnel part 3 deflection yoke 4 panel part 5 seater 6,60 retaining ring 60a notch 7 separator 8 ferrite sheet for convergence correction 9 coil bobbin A cathode ray tube (color cathode ray tube)

Claims (4)

[Claims] 1. A deflection yoke for correcting misconvergence by inserting a ferrite sheet for correcting convergence into a gap formed by being fitted on a funnel portion of a cathode ray tube, wherein the ferrite sheet for correcting convergence is inserted from both front and rear directions. A deflection yoke in which the gap is formed as possible. 2. The deflection yoke according to claim 1, wherein the rear gap is formed by a separator connecting a stop ring of the deflection yoke and a coil bobbin, and the gap is 0.5 mm to 2 mm. 3. The deflection yoke according to claim 1, wherein a notch for inserting a ferrite sheet for convergence correction is provided on the inner peripheral surface of the stop ring of the deflection yoke. 4. The convergence correction in which the convergence correction ferrite sheets are inserted from both front and rear directions of the deflection yoke according to claim 1, and the convergence correction ferrite inserted through the rear gap is swung to correct misconvergence. Method.