JP3367029B2 - Deflection yoke - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to suppression of vibration components in a deflection yoke used in a television receiver.

[0002]

2. Description of the Related Art In recent years, with the improvement in image quality of television receivers, the deflection yoke has been driven at a high frequency, and as a result, a vibration component called raster ringing is likely to occur and an image other than a signal is formed. Will appear,
This is a problem in image quality.

A conventional deflection yoke will be described below with reference to the drawings. FIG. 3 is a circuit diagram showing a configuration of a conventional deflection yoke and a circuit for driving the deflection yoke. In the figure, 10 is a horizontal deflection switching element, 11 is a damper diode, 12 is a resonance capacitor, 13 is a deflection transformer, 14 is a power supply, 15 is a deflection yoke, and 16 is an S-shaped capacitor.

The mutual relationship and operation of the above-mentioned components will be described. When the horizontal deflection switching element 10 is turned on, the power supply 14 passes through the primary winding of the deflection transformer 13,
Energy is supplied while charging the resonance capacitor 12, and a deflection current in the positive direction, which is substantially proportional to time, flows through the deflection yoke 15. Next, the horizontal deflection switching element 10
Is turned off, a sudden resonance current in the opposite direction due to the combined inductance of the inductance of the primary winding of the deflection transformer 13 and the inductance of the deflection yoke 15 and the capacitance component of the resonance capacitor 12 becomes a negative deflection current. When the current flows and the voltage across the resonance capacitor 12 becomes zero or less, the damper diode 11 becomes conductive and the resonance is dumped. Then again the horizontal deflection switching element 1
0 is turned on and a positive deflection current flows. The above operation is repeated to form the horizontal deflection current in the scanning period, and the deflection operation is continued. In the process of this operation, when the horizontal deflection switching element 10 is turned off, that is, during the blanking period, as shown in FIG. 4, a high voltage, which is several to several tens of times the voltage of the power source 14 called a deflection pulse, is generated. appear. Further, when the resonance current turns negative and the damper diode 11 is turned on, a rapid current change occurs.

Now, the deflection current is IDY, the power supply voltage is + B,
When the horizontal period is TH, the retrace line period is TF, the deflection yoke inductance is LDY, and the deflection pulse voltage is VCP, IDY = B. (TH-TF) / LDY VCP = B. [{(TH / TF) −1} · (π / 2) +1].

[0006]

In such a conventional deflection yoke and drive circuit, the values of the deflection pulse voltage VCP and the deflection current IDY are as shown in the above equation.
When the power supply voltage B of the device is predetermined,
The horizontal period is determined by TH and the flyback period is determined by TF. However, since the magnitude of the deflection pulse voltage VCP is limited by the withstand voltage of the switching element, the flyback period is naturally determined by the set value of TF, and the magnitude of the deflection current is determined. It is no exaggeration to say that the size depends on the inductance LDY. In recent years, the inductance of the deflection yoke has been set low due to the increase in frequency, and further, the inductance of the deflection yoke has been set lower in response to the increase in deflection power accompanying the large-screen wide-angle deflection. However, even if the inductance is set to a small value, the distributed capacitance between the coil winding of the deflection yoke and the ground through the peripheral object and the distributed capacitance between the windings due to the winding structure that causes the predetermined magnetic field distribution are It remains.
Therefore, parasitic oscillation occurs due to the large deflection current and the remaining distributed capacitance.

That is, a vibration component is generated due to a transient response operation at the time when a sudden current change and a corresponding sudden voltage change occur. This phenomenon usually occurs at the boundary between the blanking period and the scanning period. This effect cannot be seen when entering the blanking period from the scanning period because it is not displayed on the screen due to blanking, but when entering the scanning period from the blanking period, it is the beginning of horizontal scanning, so it is not displayed on the screen. The vibration component generated here gives velocity modulation to the electron beam, horizontal luminance change called ringing occurs on the screen, and is displayed as a line in the vertical direction on the screen. In order to improve this problem, measures such as reduction of the distributed capacitance of the deflection yoke and addition of a damping circuit are taken, but in the former case, it operates with a deflection pulse voltage that is several to ten times higher than the power supply voltage. For this reason, the distributed capacitance of the earth is affected, and even from the configuration that generates a predetermined deflection magnetic field distribution, it is not possible to realize a structure that can reduce the distributed capacitance of the winding itself or a winding distribution. is there. on the other hand,
Although the latter is effective, it not only requires high withstand voltage elements and parts, but also causes energy loss in parts other than vibration components and generates heat due to power consumption, which is uneconomical to use large parts. Various improvement measures have been taken.
As described above, there is a problem that the vibration component is generated due to the distributed capacitance of the deflection yoke with respect to the ground and that an uneconomical method is adopted to improve the vibration component.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a deflection yoke capable of reducing the distributed capacitance with respect to ground in the deflection yoke to reduce the vibration component and economically suppressing the vibration. To do.

[0009]

According to the present invention of claim 1, a positive horizontal deflection pulse is applied to one end of a deflection yoke and a negative horizontal deflection pulse is applied to the other end of the deflection yoke at the same time. A deflection yoke having an intermediate tap for connecting a damping circuit to a winding position corresponding to a voltage ratio of a deflection pulse, and the present invention according to claim 2 is a passive component between the intermediate tap and the ground. Alternatively, it is a deflection yoke provided with a damping circuit connected by an active component.

[0010]

In the present invention according to claim 1, the deflection yoke is driven by the positive deflection pulse and the negative deflection pulse, the deflection pulse voltage having a predetermined value is divided into the positive voltage and the negative voltage, and the ground voltage is increased. As the electric potential distribution of the deflection yoke with respect to ground changes, the equivalent distributed capacitance with respect to ground is reduced to reduce vibration components, and a damping circuit can be connected. In the related invention, the damping element or circuit inserted between the intermediate tap at the ground potential and the ground simultaneously damps the resonance on the positive side and the resonance on the negative side to further suppress the vibration component.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the deflection yoke of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a deflection yoke and its drive circuit of the present invention. In the figure, 1 is a horizontal deflection switching element, 2 is a damper diode, 3 is a resonance capacitor, 4 is a power supply, 5 is a deflection transformer, 6 is a deflection transformer 5, and a secondary winding for generating a negative deflection pulse, Reference numeral 7 is a deflection yoke, and 8 is an S-shaped correction capacitor. The deflection yoke 7 is driven by positive and negative deflection pulses and includes an intermediate tap P set at a winding position divided into positive and negative voltage ratios. The intermediate tap P is provided for improving ringing. The damping element or the damping circuit 9 connected between the ground and the ground is connected. The means for supplying the positive and negative deflection pulses may be another means.

The mutual relationship and operation of the above components will be described. As described above, the horizontal deflection current is formed by turning on and off the horizontal deflection switching element 1. Further, in the present invention, as an embodiment, the deflection transformer 5 is provided with the secondary winding 6, and the negative deflection pulse is supplied to the deflection yoke 7. Therefore, a positive deflection pulse is supplied to one end of the deflection yoke 7, that is, the collector or drain side of the horizontal deflection switching element 1, and a negative deflection pulse is supplied to the other end, so that the deflection operation is realized. Now
When the deflection transformer 5 is assumed to be an ideal transformer and its winding ratio is 1: n, the voltage ratio of the positive and negative deflection pulses applied to the deflection coil 7 is assumed to be 1: n.

The ground potential of the deflection yoke 7 divided into 1: n is VCP on the positive side and nVCP on the negative side, as shown in FIG. 2A. In this case, in the operation of the conventional deflection yoke, a positive pulse of VCP ′ = (VCP + n · VCP) is applied to the deflection yoke 7, whereas both the voltage VCP and the voltage n · VCP in the present embodiment. Lower than voltage VCP 'with respect to ground. Further, since the positive and negative deflection pulses are applied, an electric neutral point for the deflection pulse is inevitably formed in the winding of the deflection yoke 7, and the potential distribution with respect to the earth due to each part of the winding and the peripheral objects. Changes, and the distributed capacitance to earth, which is determined by the amount of accumulated charge, also changes, but this distributed capacitance to earth is clearer in the case where there is an electrical neutral point in the deflection yoke than in the conventional case. Reduce. Therefore, due to the deflection voltage lower than the conventional one and the distributed capacitance to ground smaller than the conventional one, the generated vibration component is reduced more than the conventional one. Further, in this embodiment, the intermediate tap P is provided at the position of the electrical neutral point on the deflection yoke.
Is set, and the damping element or the damping circuit 9 is connected to the ground. Generally, the distributed capacitance of a coil can be equivalently expressed as a lumped constant at two points, a winding start end and a winding end end. As shown in FIG. 2B, by inserting the damping element or the damping circuit 9 between the electrical neutral point and the ground, two vibrating circuits are formed around the electrical neutral point. Therefore, the damping circuit 9 commonly damps the positive vibration circuit and the negative vibration circuit to converge the vibration current. in this case,
It is needless to say that the damping element or the damping circuit may be of low withstand voltage and stop power consumption as compared with the case where it is not divided, which is economical.

As described above, according to the deflection yoke of this embodiment, the deflection yoke is driven by the positive and negative deflection pulses, and between the intermediate tap corresponding to the voltage ratio of the positive and negative deflection pulses and the ground. By inserting a damping element or a damping circuit with resistors, resistors and capacitors,
The distributed capacitance of the deflection yoke with respect to ground is reduced equivalently, and the parasitic oscillation circuit is divided into two parts, and each is effectively damped by a damping element or a damping circuit. , Low power ones are sufficient.

[0015]

As is apparent from the above description, according to the present invention, a positive horizontal deflection pulse is applied to one end of the deflection yoke, and a negative horizontal deflection pulse is applied to the other end of the deflection yoke at the same time to drive them. An intermediate tap for connecting the damping circuit to the winding position according to the voltage ratio of the deflection pulse is provided, and
By providing the damping circuit connected by the passive component or the active component between the intermediate tap and the earth, the distributed capacitance of the deflection yoke with respect to the earth can be equivalently reduced, and the oscillating circuit can be equally divided into two. The vibration components can be effectively and economically suppressed by the damping element or the damping circuit having lower breakdown voltage and lower power than the conventional ones.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a drive circuit for a high-frequency deflection coil according to the present invention.

FIG. 2 is a circuit diagram showing an operation equivalent circuit of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a typical conventional horizontal deflection circuit.

FIG. 4 is a waveform diagram showing a deflection pulse.

[Explanation of symbols]

7 Deflection yoke 9 Damping circuit P middle tap

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 29/76 H04N 3/16

Claims (2)

(57) [Claims] 1. A positive horizontal deflection pulse is applied to one end of a deflection yoke, and a negative horizontal deflection pulse is applied to the other end of the deflection yoke at the same time to drive, and damping is performed at a winding position corresponding to a voltage ratio of the applied positive and negative deflection pulses. A deflection yoke with a center tap for connecting circuits. 2. The deflection yoke according to claim 1, further comprising a damping circuit connected by a passive component or an active component connected between the intermediate tap and the ground.