JPS60149263A - Horizontal deflecting circuit - Google Patents

Abstract

PURPOSE:To correct accurately the bobbin distortion deflected horizontally and to improve the characteristics of a horizontal deflecting circuit, by changing the power supply voltage of a horizontal deflection basic circuit by a correction signal corresponding accurately to the vertical deflection distance from the centerof a CRT. CONSTITUTION:The voltage VC of a basic circuit 7 of a horizontal deflecting circuit is connected to the emitter of a transistor TR6 which serves as a correction circuit. While the DC voltage VCC is connected to the collector of the TR6, and a correction signal VC correcsponding accurately to the vertical deflection distance from the center of a CRT is supplied to the base of the TR6. Then the voltage VC corresponding to the signal VC is delivered to the emitter of the TR6. Thus the amplitude is modulated for a deflection signal iy of a ramp waveform which flows to a deflecting coil 8 that is controlled by a signal VB. This corrects accurately the bobbin distortion deflected horizontally and improves the characteristic of the horizontal deflecting circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a horizontal deflection circuit in a TV rask scan display using a cathode ray tube (CRT).

FIG. 1 shows the basic circuit of this type of horizontal deflection circuit. A conventional horizontal deflection circuit uses a choke coil.

It consists of a transistor 2 whose collector is connected to the choke coil 1, a damper diode 3 connected in parallel to the transistor 2, a capacitor 4, and a deflection coil 5. The flowing current ly is controlled.

Figures 2(a), (b), and (C) show the power supply voltage V of the circuit in Figure 1.
c,) shows the control signal input to the base of the transistor 2 and the deflection current lj flowing through the deflection coil 5, and as is clear from the figure, the deflection current has a ramp waveform with a constant amplitude.

By the way, in a normal cathode ray tube, the radius of curvature in the fluorescent direction is larger than the axial distance from the center of deflection to the fluorescent surface.
On the fluorescent surface, there was a problem in that the rectangle that should be shown by the dotted line in FIG. 3 was distorted into a pincushion shape as shown by the solid line.

Conventionally, a saturable reactor method has been used to correct this pincushion distortion as shown by the dotted line in Figure 3, but this saturable reactor method utilizes the saturation characteristics of magnetism.
It has been difficult to accurately correct pincushion distortion because the magnetic saturation characteristics and the amount of correction do not match.

An object of the present invention is to provide a horizontal deflection circuit that can accurately correct pincushion distortion.

In order to achieve the above object, the horizontal deflection circuit according to the present invention is a horizontal deflection circuit of a TV rask scanning display device, and includes a correction circuit that changes the power supply voltage by a correction signal corresponding to the vertical deflection distance from the center of the cathode ray tube, and a correction circuit that changes the power supply voltage by a correction signal corresponding to the vertical deflection distance from the center of the cathode ray tube; a horizontal deflection basic circuit whose power source is a voltage controlled by the circuit, and configured to amplitude-modulate a ramp waveform polarization current flowing through a deflection coil of the horizontal deflection basic circuit with a vertical deflection distance. .

According to the above configuration, pincushion distortion can be accurately corrected, and the object of the present invention is completely achieved.

Invention X will be explained in more detail below with reference to the drawings.

FIG. 4 is a circuit diagram showing an embodiment of the horizontal deflection circuit according to the present invention. In the figure, 7 is the horizontal deflection basic circuit, and the first
The configuration is the same as the one shown in the figure. The power supply Vc of this basic horizontal deflection circuit 7 is connected to the emitter of a transistor 6 which is a correction circuit. The collector of transistor 6 is DC power supply Vc
c, and a correction signal corresponding to the vertical deflection distance with respect to the center of the cathode ray tube is input to the base.

A voltage Vc corresponding to the correction signal VC is output to the emitter of the transistor 6.

Therefore, the ramp waveform deflection signal iy controlled by the signal VB and flowing to the deflection coil 8 has an amplitude modulated waveform.

! 5(a), (b), (c), (d), and (e) are the power supply voltage and correction signal vc applied to the collector of the transistor 6.

The waveforms of the voltage Vc applied to the basic horizontal deflection circuit, the signal VB input to the pace of the transistor 9, and the deflection current are shown, respectively.

As a result, horizontal pincushion distortion is corrected.

Although the deflection angle and curvature differ depending on the type of cathode ray tube, the pincushion distortion of various cathode ray tubes can be easily corrected by changing the amplitude and shape of the correction signal vc accordingly.

As described in detail above, the present invention has the effect of accurately correcting pincushion distortion in horizontal deflection by changing the power supply voltage of the basic horizontal deflection circuit using a correction signal that accurately corresponds to the vertical deflection distance from the center of the cathode ray tube. There is.

[Brief explanation of drawings]

Figure 1 is a basic circuit diagram of the horizontal deflection circuit, Figure 2 is a waveform diagram to explain the operation of Figure 1, Figure 3 is a diagram showing pincushion distortion on the fluorescent surface, and Figure 4 is the main FIG. 5 is a circuit diagram showing an embodiment of the horizontal deflection circuit according to the invention, and FIG. 5 is a waveform diagram for explaining the operation of FIG. 4. 1... Choke coil 2.6.9... Transistor 3... Damper diode 4... Capacitor 5...
・Deflection coil 7...Basic circuit of horizontal deflection circuit Patent applicant: NEC Corporation Representative, Patent attorney Hisashi Inoro 21 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A horizontal deflection circuit of a TV scan type display device includes a correction circuit that changes the power supply voltage according to a correction signal corresponding to the vertical deflection distance from the center of the cathode ray tube, and a horizontal deflection circuit whose power source is the voltage controlled by the correction circuit. 1. A horizontal deflection circuit, comprising a basic circuit, and configured to amplitude-modulate a ramp waveform deflection current flowing through a deflection coil of the horizontal deflection basic circuit according to a vertical deflection distance.