JPH06350864A - Display picture adjustment circuit - Google Patents

Abstract

PURPOSE:To obtain a display picture adjustment circuit for a horizontal direction having also a picture distortion correcting function by providing an integration circuit to convert vertical DY deflecting current waveform into parabolic waveform, and giving its output to the output of a frequency-voltage conversion circuit. CONSTITUTION:In the display picture adjustment circuit dealing with multiscanning, in order to improve bow-shaped picture distortion to the same direction at both the sides of a screen caused by the performance of a deflecting DY or a circuit system, the output current of a constant current circuit 8 to determine the signal delay quantity of a monostable multivibrator 2 is controlled by the parabolic waveform. Therefore, the saw tooth wave deflecting current of the vertical DY is supplied to a terminal 9. This saw tooth wave deflecting current is integrated by the integration circuit 10, and the parabolic waveform of a vertical period is formed. The distortion of a display picture can be improved by controlling the output current of the constant current circuit 8 by adding the parabolic waveform to the output voltage of the frequency-voltage conversion circuit 7. Besides, since the picture distortion correcting function and a picture display position adjusting function are uited and simplified, the addition of parts can be managed with a small quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT multi-scan display which inputs two or more horizontal synchronizing frequencies, and more particularly to a display image adjusting circuit having a screen distortion correcting function.

[0002]

2. Description of the Related Art In recent years, so-called multi-scan displays, which are compatible with various horizontal frequencies, have become the mainstream of computer displays. Therefore, a problem is the shift of the image display position in the horizontal direction that occurs when the input frequency is switched. As an effective means for solving this problem, for example, as described in Japanese Patent Laid-Open No. 63-30071, a phase relationship between a video signal and a horizontal synchronizing signal is controlled by using a DC voltage proportional to an input horizontal frequency. A display image adjusting circuit is known.

FIG. 4 shows a display image adjusting circuit. In this circuit, the output voltage Vs of the frequency-voltage conversion circuit 7 is the constant current circuit 8
, And its output current controls the delay time of the monomulti 2. Mono-multi 2 and mono-multi 3 generate a delayed horizontal synchronizing signal having a predetermined pulse width. The output signal of the monomulti 3 is supplied to the horizontal AFC circuit 4, and the horizontal deflection current generated by the horizontal oscillator 5 and the horizontal output circuit 6 is supplied to the horizontal deflection coil.

The circuit operation of FIG. 4 will be briefly described with reference to FIGS. 5 and 6. A horizontal sync signal B output from a computer with respect to an input video signal A of an arbitrary signal source is a video signal A which is almost the same as the screen. Since the horizontal sync delay signal C is controlled so as to be positioned at the center, the shift of the horizontal image display position caused by the difference in the timing of the video signal with respect to the horizontal sync signal as shown in FIG. 6A can be reduced. ,
In addition, the display image can be made to be substantially at the center of the screen as shown in FIG. 6B regardless of the horizontal frequency.

[0005]

By the way, the present CR
In the T display, various screen distortions represented by side pin distortion occur due to deflection DY and circuit performance problems, and there is a problem that an original distortion correction circuit is required.

Therefore, according to the present invention, the arcuate screen distortion in the same direction on both sides of the screen can be easily constructed by adding a parabola waveform obtained by integrating the vertical DY deflection current waveform to a horizontal image shift circuit corresponding to multi-scan. It is an object of the present invention to provide a display image adjustment circuit with a screen distortion correction function capable of performing the above.

[0007]

According to the present invention, in a display image adjusting circuit for multi-scan, an integrating circuit for converting a vertical DY deflection current waveform into a parabolic waveform is provided, and the output is converted into a conversion voltage proportional to a horizontal frequency. It is characterized in that the added signal is applied to the horizontal oscillation circuit.

[0008]

According to the above construction, a parabola waveform is formed by an integrator circuit having a sawtooth-shaped vertical DY deflection current waveform as an input, and this output is given to the output of the frequency-voltage conversion circuit so as to have a screen distortion correction function. A horizontal display image adjustment circuit can be configured.

[0009]

EXAMPLE An example of the present invention will be described below.

FIG. 1 shows an embodiment of the present invention. In FIG. 1, the horizontal synchronizing signal Hs is input to the terminal 1.
The horizontal synchronizing signal Hs is supplied to the mono-multi 2 and the frequency-voltage conversion circuit 7. Mono-multi 2 is horizontal sync signal Hs
Is used as a trigger to delay the signal by the delay time Td set by the output of the constant current circuit 8 described later. The delayed signal of the mono-multi 2 is supplied to the mono-multi 3, and the mono-multi 3 generates a delayed horizontal synchronizing signal having a predetermined pulse width. This horizontal synchronizing signal is input to the horizontal AFC circuit 4. Further, this output signal passes through the horizontal oscillation circuit 5 and the horizontal oscillation circuit 6, and a horizontal deflection current is supplied to the horizontal deflection coil (not shown). Here, the feature of the present invention is that in order to improve the bow-shaped screen distortion (refer to FIG. 3) in the same direction on both sides of the screen, which is caused by the deflection DY and the performance of the circuit system, the constant delay that determines the signal delay amount of the monomulti 2 is used. The point is that the output current of the current circuit 8 is controlled by the parabolic waveform. Vertical D for terminal 9
A Y sawtooth deflection current is supplied. The sawtooth deflection current is integrated by the integrating circuit 10 to form a parabolic waveform with a vertical cycle. By adding the parabolic waveform to the output voltage of the frequency-voltage conversion circuit 7 and controlling the output current of the constant current circuit 8, it is possible to improve the distortion of the display image as shown in FIG.

FIG. 2 shows a signal waveform used for screen distortion correction, and FIG. 3 shows the corrected sync signal timing at each position of the screen distortion shown on the right side of FIG. In the screen distortion of FIG. 3, now, e
It is assumed that the horizontal positions of points d and f are shifted from each other by the same amount. The vertical deflection current waveform 9 in FIG.
Is converted into a horizontal phase control signal (parabola waveform) 11 by. The meaning of this signal is that in the screen distortion shown in FIG. 3, the phase of the horizontal synchronizing signal is controlled by the potential d at the screen point d, the potential e at the screen point e, and the potential f at the screen point f. Therefore, the horizontal sync signal timing after screen distortion correction for the video signal A is horizontal sync signal D at the upper part of the screen (point d), horizontal sync signal E at the central part of the screen (point e), and horizontal at the lower part of the screen (point f). It becomes the synchronization signal F. The horizontal image shift amount at the screen points d and f and the screen point e corresponds to the delay time Td of the horizontal synchronizing signal.

According to the above configuration, the parabolic waveform obtained by integrating the vertical deflection current waveform is used for the horizontal phase control, so that the arcuate screen distortion in the same direction can be reduced.
Moreover, the screen display position adjustment function is not lost. further,
With a specific circuit configuration, as shown in FIG. 1, relatively few parts need to be added (several points such as resistors R and capacitors C ₁ and C ₂ ). Further, it goes without saying that the present invention can also be applied to the arcuate screen distortion in the same direction in the opposite direction by inverting the parabolic waveform.

[0013]

As described above, according to the present invention,
Since the parabola waveform obtained by the integrating circuit using the vertical DY sawtooth deflection current waveform as an input is added to the horizontal display position control signal, the screen distortion correction function and the screen display position adjustment function are simplified together. It is possible to configure a circuit relatively easily with less addition of parts due to additional functions, and it is possible to reduce bow-shaped screen distortion in the same direction. Furthermore, the original display image adjusting function can be ensured.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a display position adjusting circuit according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a horizontal phase control waveform used in the present invention.

FIG. 3 is a diagram showing an example of a correction waveform in an example of the present invention.

FIG. 4 is a configuration diagram of a conventional display position adjusting circuit which is a basis of the present invention.

FIG. 5 is a diagram showing an example of signal timing of a conventional display position adjusting circuit which is a basis of the present invention.

FIG. 6 is a diagram showing an example of an image shift operation of a display position adjustment circuit which is the basis of the present invention.

[Explanation of symbols]

1 ... Horizontal sync signal input terminal, 2-3 ... Mono-multi, 4 ...
Horizontal AFC circuit, 5 ... Horizontal oscillation circuit, 6 ... Horizontal output circuit, 7 ... Frequency-voltage conversion circuit, 8 ... Constant current circuit, 9 ...
Vertical DY deflection current waveform, 10 ... Integrator circuit, 11 ... Horizontal phase control signal, Hs ... Input horizontal synchronization signal, Vs ... Frequency-
Voltage conversion circuit output voltage, A ... video signal, B ... input horizontal sync signal waveform, C ... horizontal sync delay signal waveform, D ... screen upper part (point d), corrected horizontal sync signal waveform, E ... screen central part ( e point), horizontal sync signal waveform after correction, F ... lower part of screen (point f), horizontal sync signal waveform after correction, d ... upper part of screen,
e ... central part of screen, f ... bottom part of screen, (a) ... image before horizontal display position adjustment, (b) ... image after horizontal display position adjustment.

Claims (1)

[Claims] 1. A horizontal display position adjusting circuit for a multi-scan display, to which two or more different horizontal synchronizing frequencies are supplied, an integrating circuit for converting a sawtooth vertical DY deflection current waveform into a parabolic waveform, and a horizontal synchronizing frequency. A frequency-voltage conversion circuit for converting the input voltage into a DC voltage proportional to the frequency, a means for combining the two circuit outputs, and a correction signal for adjusting the screen horizontal position and the screen distortion by the combined output signal. A display image adjusting circuit comprising a delay circuit.