JPS6022698Y2 - Pink tension distortion correction circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bin cushion correction circuit in a display device using a color cathode ray tube.

Generally, when deflection is performed by supplying a sawtooth wave current to a deflection coil in a display device using a color cathode ray tube, vertical and horizontal bottle cushion distortion occurs in the delta gun type cathode ray tube.

On the other hand, in-line gun type cathode ray tubes produce left and right bin cushion distortion.

Conventionally, as means for correcting the distortion, a method has been adopted in which a parabolic current (a current having a parabolic waveform) derived from a vertical deflection waveform is supplied to a variable reactor.

However, when displaying graphics particularly in character displays used for computer terminals, conventional correction circuits alone are often insufficient for color display.

Therefore, the present invention provides a new bottle cushion distortion correction circuit that eliminates the above-mentioned drawbacks.The explanation will be given below according to the drawings.FIG. 1 shows the bottle cushion distortion correction circuit of the present invention, and FIG. Explanatory screen diagram of the devised circuit, Figure 3 A9
The opening shows an explanatory waveform diagram of the circuit of the present invention.

In the drawing, 1 is a vertical deflection circuit, 2 is a vertical deflection coil, 3 is a coupling capacitor, 4 is a first series circuit consisting of a resistor 5 and a capacitor 6, and 7 is a second series circuit consisting of a resistor 8.9 and a capacitor 10. Series circuit, 11 is a correction loop consisting of a resistor 12 and a diode 13, 14 is a primary coil 15
and a correction transformer having a secondary coil 16, 17 a coupling capacitor, 18 a horizontal deflection coil, 19 a horizontal deflection circuit, and a vertical deflection current and a horizontal deflection current 8 are assumed to flow through each of the coils.

The screen without the correction circuit shown by the broken line in Figure 1 is as follows:
The bottle cushion distortion (pincushion distortion) shown in FIG. 2A appears, but as described above, when parabola correction is performed, the waveform becomes as shown by the solid line at the beginning of FIG. 2, and the linearity of the periphery cannot be corrected completely.

Therefore, when using the circuit of the present invention shown in FIG. The waveform of part B is corrected as shown by the broken line.

That is, first, the parabolic voltage obtained by the first series circuit 4 is connected to the primary winding 15 of the correction transformer 14 by the diode 13.
The negative polarity current flowing towards the diode 13 is enhanced (forward current of the diode 13), while the positive polarity current flowing in the opposite direction of the diode 13 flows through the resistor 8.

At this time, the resistor 8 is larger than the forward impedance of the diode 13, so the positive polarity current is suppressed.

Here, a second series circuit 7 is connected in parallel to the primary coil 15 of the correction transformer 14, and its resistor 9 and capacitor 10 change the phase of the correction current flowing through the primary coil 15. The position of the bottle cushion in the vertical direction can be corrected by integrating the correction voltage by the first series circuit 4 and using a time constant determined by the resistor 9 and capacitor 10.

Therefore, compared to the case where only the parabolic waveform is corrected, the horizontal deflection current IH flowing through the horizontal deflection coil 18 in the circuit of the present invention is corrected from the dashed line waveform to the broken line waveform as shown in the opening of FIG. The upper raster becomes almost a straight line as indicated by the broken line in FIG. 2, and the linearity of the entire screen is improved.

As described above, according to the present invention, when a current with a waveform obtained by shaping the horizontal deflection current is superimposed on the horizontal deflection current, it is not a conventional parabolic waveform current, but a current with a waveform close to a trapezoid. The accompanying bottle cushion distortion can be removed, and the present invention is particularly useful as a character display that performs overscanning for a display device for a terminal of a slave computer.

[Brief explanation of the drawing]

FIG. 1 shows the bottle cushion distortion correction circuit of the present invention, FIG. 2, A-9, is a screen diagram for explaining the circuit, and FIG. Explanation of main figure numbers, 1... Vertical deflection circuit, 2...
Curved vertical deflection coil, 4...First series circuit, 7.
Song/Second series circuit, 11...Correction loop, 14
... Correction transformer, 18 ... Horizontal deflection coil, 19 ... Bent wood flat deflection circuit.

Claims (1)

[Scope of utility model registration request] a first series circuit consisting of a resistor and a capacitor to which a vertical deflection signal from the vertical deflection circuit is applied; a resistor and a correction transformer connected in series are connected in parallel to the first series circuit; A second series circuit consisting of a resistor and a capacitor is connected, a third series circuit consisting of a diode and a resistor is connected in parallel to the resistor connected in series with the correction transformer, and the correction signal obtained by the correction transformer is horizontally deflected. In addition to the circuit, a bottle cushion distortion correction circuit is characterized in that it removes bottle cushion distortion.