JPH01183042A - Deflecting yoke for in-line type color picture tube - Google Patents

Abstract

PURPOSE:To improve the convergence property by connecting a diode couple to coma correcting coils and the vertical side winding of a saturable reactor unit in series. CONSTITUTION:A vertical deflecting coil 12, two sets of coma correction coils 1a and 1b, and a vertical side winding 2 of a saturable reactor unit are connected in series, and between a part 2a and the other part 2b of the winding 2, a diode couple 3 of an inverse parallel is connected in series. From the time when the voltage between both ends of a resistance 4 exceeds the starting voltage of the diode, a vertical deflecting current flows in to the coil 1a and the part 2a of the winding 2 suddenly, and thereby, a super linear correcting property as the whole including the other part 2b can be obtained respectively. Consequently, the vertical direction coma error near the central part of the vertical axis and the cross misconvergence near the central part can be corrected at optimum level simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a deflection yoke for an in-line color picture tube.

(Prior Art) In general, a color picture tube with an in-line electron gun is characterized by making the magnetic field of the deflection yoke non-uniform.
It has a so-called self-convergence function in which the three electron beams are made substantially coincident over the entire screen by only the combination of the color picture tube and the deflection yoke without using any external circuit correction means.

This type of deflection yoke for in-line color picture tubes is
Conventionally, the configuration is as shown in FIG. That is, this deflection yoke is of a semi-toroidal type, and includes a pair of upper and lower saddle-shaped horizontal deflection coils 11 disposed inside the ferrite core 10, and a pair of upper and lower toroidal deflection coils wound directly around the ferrite core 10. Vertical deflection coil 12
have.

Even in such a self-convergence type deflection yoke, it is extremely difficult to completely eliminate convergence errors using only the winding distribution of the horizontal and vertical deflection coils. Convergence errors can be roughly divided into errors between side beams and errors between side beams and center beams.

Side beams (usually R and B) and center beam (usually G
) is generally called a coma error, but
One method for correcting this is to provide a coma correction coil on the end surface of the deflection yoke on the electron beam side. Fifth
The figure shows an example of this, which corrects a coma error (VCR) related to vertical deflection, and is connected to the vertical deflection coil 12 of FIG. 4, and is supplied with a vertical deflection current.

On the other hand, as a method to correct errors between side beams,
A method that has been used recently is a method using a saturable reactor, which will be described below. In this case, the convergence error is the cross-miss convergence (PQv
lSl, s2, s3), and other errors are corrected in advance. FIG. 7 shows a typical configuration of the saturable reactor unit 15, which includes two sets of four saturable reactors 16a and 16b each having a horizontal winding wound thereon.

The vertical winding 2 is wound around the entirety of 16c and 15d. In addition, four saturable reactors 16a116b, 16
c and 16d are magnetically biased by a permanent magnet 17.

With this configuration, the vertical deflection current flowing in the vertical winding 2 differentially modulates the inductance seen from the two sets of horizontal terminals of the saturable reactor, thereby changing the deflection current flowing in the upper and lower horizontal deflection coils 11. By providing a difference and making the horizontal deflection magnetic field vertically asymmetric, the cross misconvergence shown in FIG. 6 can be corrected.

FIG. 8 is a typical wiring diagram of a deflection yoke using the saturable reactor unit 15.

(Problems to be Solved by the Invention) FIG. 9 shows a typical convergence error pattern that remains when the coma error is corrected by the above-mentioned coma correction coil. In the figure, the vertical axis end 20 is corrected to zero, but the G beam is excessively deflected due to overcorrection at the vertical axis intermediate portion 21. Also, when looking at the horizontal lines of the raster, a phenomenon called G Droop occurs, in which the center beam droops at the periphery relative to the side beams. The above-mentioned overcorrection near the vertical axis intermediate portion 21 is 0.1 to 0.2 mm in a 14-inch color picture tube.
However, in reality, it is a compromise design with insufficient correction in some corners due to G Droop, and since it is necessary to further strengthen the coma error correction, overcorrection in the intermediate portion tends to be promoted.

On the other hand, FIG. 10 shows an example of the error that remains when cross-misconvergence is corrected using a saturable reactor in the case of a relatively large picture tube such as a 20-inch color picture tube. In this case, before correction by the saturable reactor, PQv remains negative (the pattern in Figure 6 is positive), and when this is corrected, the cross-misconvergence S2 and S3 in the middle are overcorrected. There is. The reason for this is that the correction by the saturable reactor is approximately linear with respect to the distance d along the horizontal axis.

An object of the present invention is to solve the above-mentioned conventional problems and provide a deflection yoke for an in-line color picture tube having good convergence characteristics.

, [Structure of the Invention] (Means for Solving the Problems) The above conventional problem is that both the coma error correction by the coma correction coil and the cross-mistake convergence correction by the saturable reactor unit are This is because the curve is generally linear.

Therefore, in the present invention, a diode pair is connected in series with the coma correction coil and the vertical winding of the saturable reactor unit.

(Function) According to the present invention, a squirrel-bar linear correction characteristic is obtained by utilizing the nonlinear rise characteristic of the diode, and the vertical coma error near the vertical axis middle part, which has been a problem in the past, and the cross correction near the middle part are solved. Misconvergence can be optimally corrected at the same time.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The deflection yoke of the present invention is constructed as shown in FIG. 1, and includes a vertical deflection coil 12 and two sets of coma correction coils l.
a -, 1b and the vertical side winding 2 of the saturable reactor unit are connected in series, and this vertical side winding, part 2a of the line 2
A pair of anti-parallel diodes 3 are connected in series between the other part 2b and the other part 2b. Furthermore, for a series circuit of one set 1a of the coma correction coils la and lb, a part 2a of the vertical winding 2 of the saturable reactor unit, and a diode pair 3,
A resistor 4 is connected in parallel.

In the case of this embodiment, the nonlinearity of the forward direction V-1 characteristic of the diode shown in FIG. ), the vertical deflection current suddenly flows into the coma correction coil 1a and part 2a of the vertical side winding 2 of the saturable reactor unit, so that the coma correction sub coil 1b and the vertical side winding of the saturable reactor unit Superlinear correction characteristics can be obtained as a whole including the other portion 2as2b of the line 2. Therefore, it is possible to simultaneously correct the intermediate misconvergence patterns shown in FIGS. 9 and 10, which have been described as problems.

The two sets of coma correction coils in this embodiment can be wound on separate cores as shown in FIG. 3, or split and wound on the same core of the coma correction coil as shown in FIG. There is a way to turn it.

Furthermore, the diode pair may be in reverse series (in this case, Zener diodes are used and their nonlinear characteristics in the opposite direction are utilized).

In addition, in this invention, the value of the resistor 4, the type of diode, and the winding 1 a, 1 bs 28% 2. It is important to appropriately select the resistance value of b.

(Modified Example) In the above embodiment, a semi-toroidal deflection yoke has been described, but the present invention can also be applied to a saddle-shaped deflection yoke in which both the horizontal and vertical deflection coils are saddle-shaped.

[Effects of the Invention] According to the present invention, it is possible to simultaneously optimally correct the vertical coma error near the middle part of the vertical axis and the cross misconvergence near the middle part, which have been problems in the past.
It is possible to realize a deflection yaw for an in-line color picture tube having good convergence characteristics.

[Brief explanation of the drawing]

FIG. 1 is a wiring diagram showing a vertical deflection coil in a deflection yoke for an in-line color picture tube according to an embodiment of the present invention, and FIG. 2 is a characteristic curve showing the forward direction VI characteristic of the diode used in the present invention. 3 is a wiring diagram showing an example of the coma correction sub-coil consisting of two sets used in this invention, FIG. 4 is a perspective view showing a general semi-toroidal deflection yoke, and FIG. 5 is a conventional coma correction sub-coil. A wiring diagram showing an example of a correction sub-coil, Fig. 6 is an explanatory diagram showing cross-misconvergence, Fig. 7 is a plan view showing a saturable reactor unit, and Fig. 8 is a wiring diagram showing a deflection yoke with a saturable reactor unit. Fig. 9 is an explanatory diagram showing a typical coma error pattern, and Fig. 10 is a characteristic curve diagram showing an example of a cross-mistake convergence error. la, lb...coma correction coil, 2a12b...
・Vertical side winding of the saturable reactor unit, 3...
Diode pair, 4...Resistor, 11...Horizontal deflection coil, 12...Vertical deflection coil. Figure 1! Le Fig. 3 F Fig. 4 Fig. 5 Fig. 6 ■ Terminal Fig. 7

Claims (1)

[Claims] A pair of horizontal deflection coils that deflect in the array direction of an in-line electron gun, a pair of vertical deflection coils that deflect in a direction perpendicular to the array direction, and a coma error between three electron beams related to vertical deflection. and at least one set of coma correction coils for correction, and differentially changing the horizontal deflection current flowing through each horizontal deflection coil by the action of a saturable reactor modulated by the vertical deflection current, In an in-line color picture tube deflection yoke that corrects convergence in the vertical direction with respect to an electron gun array, the vertical deflection coil, the coma correction coil, and the vertical winding of the saturable reactor are sequentially connected in series; A pair of anti-parallel diodes is connected in series between a part of the vertical winding and the other part, and a part of the coma correction coil, a part of the vertical winding, and the anti-parallel diode pair are connected in series. A deflection yoke for in-line color picture tubes characterized by a resistor being connected in parallel to the circuit.