JPH03173049A - Deflection yoke - Google Patents

Abstract

PURPOSE:To obtain the preventive effect of wavy ringing and the reducing effect of frequency dependance of convergence by specifying the ratio of the self-inductance of a pair of saddle-form vertical deflecting coils connected in series each other, and the resistance values of resistances connected in parallel to both vertical deflecting coils respectively. CONSTITUTION:The ratio P (=L/R) of the self-inductances L (mH) of a pair of saddle-form vertical deflecting coils 1 and 2 connected in series each other to the resistance values R (kOMEGA) of resistances 12 and 13 connected in parallel to the vertical deflecting coils 1 and 2 respectively is made 3 to 40. When the P value exceeds 40, the Q dumping effect of the vertical deflecting coils 1 and 2 is increased, while the frequency dependent property of convergence is reduced. And when the P value is less than 3, the effect of the Q dumping is reduced, making liable to generate a wavy ringing, and the frequency dependent property of convergence is increased. Consequently, the generation of wavy ringing can be prevented sufficiently, and the frequency dependent property of convergence can be reduced sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a deflection yoke mounted on a color picture tube equipped with an in-line electron gun.

Conventional technologyWhen horizontal lines of blue, green, or red are projected on the phosphor screen surface of a color picture tube equipped with an in-line electron gun,
Wave-like undulations as shown in FIG. 5 may occur.

This phenomenon occurs when the ringing current induced in the saddle-type vertical deflection coil is superimposed on the vertical deflection current, and the ringing current occurs at approximately the same period as the horizontal retrace period, as shown in FIG.

In order to eliminate this wave-like ringing, resistors 3 and 4 are connected in parallel to a pair of saddle-type vertical deflection coils 1 and 2, which are connected in series, as shown in FIG. However, it is not always possible to obtain an appropriate Q damping effect.

For example, as shown in FIG. 8, if the vertical symmetry of the coils 5.6 is impaired due to an error that occurs during the step of combining a pair of saddle-type vertical deflection coils 5.6, the neutral point of the bridge circuit a.

5, a differential current as shown in FIG. 9 flows, and a quadrupole magnetic field as shown by the broken line in FIG. 10 is generated.
a, and + for the red light emitting electron beam RR.
A Lorentz force VFR in the y direction acts on each of them.

The differential current is approximately 25 times the horizontal deflection period after the horizontal scan is completed.
50% period, the blue and red lines on the phosphor screen surface cause misconvergence 8B, 8R at the left end as shown in FIG. Furthermore, the differential current changes as the horizontal retrace period changes, and the pre-at misconvergence changes in proportion to the differential current.

In order to achieve such frequency dependence of convergence,
As shown in FIG. 12, a resistor 9.10 is connected in parallel to a pair of saddle-type vertical deflection coils 1 and 2 connected in series, and an inductor 11 is connected between neutral points a and b of the bridge circuit. There has been a proposal to cut the differential current flowing in the horizontal deflection period by connecting the
In this case, the inductor 11 also cuts off the ringing current of frequency components higher than the horizontal deflection frequency, which impairs the Q-damping effect.

Problems to be Solved by the Invention Therefore, it is an object of the present invention to provide a deflection yoke that can prevent wavy ringing and in which the frequency dependence of convergence at the left end of the phosphor screen surface is slight. be.

According to the invention, each self-inductance L (mH) of a pair of saddle-type vertical deflection coils connected in series with each other.
and the resistance value R (KΩ) of the resistor connected in parallel to each of the vertical deflection coils, the ratio P (=L/R) is 3 to 4.
Make it 0.

With this configuration, it is possible to sufficiently prevent the occurrence of wave-like ringing as described above, and furthermore, it is possible to minimize the frequency dependence of convergence as described above.

Example Next, the present invention will be explained along with examples.

This embodiment is a saddle-saddle type deflection yoke (hereinafter referred to as SS deflection yoke) in which both the horizontal and vertical deflection coils are saddle-shaped, and is for a 14-inch 90-degree deflection type color picture tube. The first diagram shows the connection of the vertical deflection coil.
In the figure, resistors 12.13 are connected in parallel to a pair of saddle-type vertical deflection coils 1.2, which are connected in series. A series connection body consisting of a diode 14 and a correction coil 15 and a series connection body consisting of a diode 16 and a correction coil 17 are connected in parallel to the high voltage terminal a side of this bridge circuit.
An auxiliary circuit is added in which a resistor 18 is connected to the diode 4 and a resistor 19 is connected in parallel to the diode 16.

The correction coils 15, 17 of this circuit have a quadrupole magnetic field for correcting vertical isotropic astigmatism 20B, 2OR as shown in FIG. A hexapole magnetic rise is generated near the electron gun side opening of the deflection yoke in synchronization with the vertical deflection period.

The total inductance of the horizontal and vertical deflection coils of the SS deflection yoke having such a vertical deflection circuit is 0.394 mH, 5, and 25 mH, respectively, and the self-inductance L of the vertical deflection coils 1 and 2 is 2. As OOmH, each resistance value R of resistor 12.13 is IKΩ (that is, L/
R=P=2.0) and 220Ω (i.e. P
=9'', 1), the frequency dependence of convergence becomes as shown by a and b in FIG.

That is, the amount of misconvergence caused by changing the horizontal retrace period from 8 μs to 3.2 μs is P =
2.0, it is 0.14mm, whereas P=9.1
In this case, it will be as small as 0.03 am.

When the P value exceeds 40, the Q damping effect of the vertical deflection coil 1.2 increases, while the frequency dependence of convergence is reduced. However, since the DC resistance value of the resistors 12 and 13 becomes too small, the vertical deflection power increases due to the current that does not contribute to beam deflection. Furthermore, if the P value is less than 3, the effect of the Q damping is reduced, wavy linking is likely to occur, and the frequency dependence of convergence becomes large. Therefore, the appropriate value range for P is 3 to 4
It is 0.

Although the above description has been made regarding the SS deflection yoke to be attached to a 14-inch 90-degree deflection type in-line color picture tube, the present invention can also be applied to a deflection yoke having at least one pair of saddle-type vertical deflection coils. Can be done.

Effects of the Invention Since the present invention is configured as described above, it is possible to achieve both the effect of preventing wave-like ringing and the effect of reducing the frequency dependence of convergence at a very low cost.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram of the vertical deflection circuit of a deflection yoke implementing the present invention, Fig. 2 is an illustration of vertical isotropic astigmatism, Fig. 3 is an illustration of vertical coma aberration, and Fig. 4 is a phosphor screen. A characteristic diagram showing the frequency dependence of convergence λ at the left end of the surface, Figure 5 is an explanatory diagram of wave-like ringing, Figure 6 is a waveform diagram of ringing current, Figure 7 is a wiring diagram of a conventional vertical deflection circuit, Figure 8 is a diagram to explain the assembly error of a pair of vertical deflection coils, Figure 9 is a waveform diagram of the differential current in the horizontal deflection period, and Figure 10 is the waveform generated when the differential current flows through the vertical deflection coils. Figure 11 is an explanatory diagram of misconvergence caused by differential current flowing through the vertical deflection coil.
FIG. 12 is a wiring diagram of a conventional vertical deflection circuit. 1.2... Vertical deflection coil, 12.13...
...Resistance, 14.16...Diode, 15
．． 17. Old correction coil, 18. Resistor for 19.

Claims (1)

[Claims] Each self-inductance L (mH) of a pair of saddle-type vertical deflection coils connected in series with each other, and the resistance value R (K
A deflection yoke characterized by having a ratio (L/R) of 3 to 40.