KR19990009531A - Luminance Correction Device of Image Display Equipment - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly, to a luminance correction device of an image display device for compensating luminance of upper, lower, left, and right sides of a CRT screen by combining vertical and horizontal parabola waveforms with a cathode current indicating luminance unbalance in right, left, and top of a CRT. .

In the brightness adjusting apparatus of the conventional video display device, the amplification ratio of the image amplifier is adjusted by the superimposed vertical parabola wave and the horizontal parabola wave, and the amplification and reproduction of the image signal to be reproduced at the corner portion rather than the center of the screen is performed. The brightness between the corners was adjusted, but the brightness of the screen top, bottom, left and right was not corrected.

Therefore, in order to solve the above problems, the present invention clamps a parabola composite signal obtained by synthesizing a horizontal parabola waveform in a vertical parabola waveform and outputs it to a preamplifier, thereby correcting the brightness above and below the screen by the vertical parabola waveform and horizontal parabola. Since the brightness of the left and right of the screen is corrected by the waveform, the main purpose is to provide a clear picture quality to the user and to improve the quality of the product.

Description

Luminance Correction Device of Image Display Equipment

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly, to a luminance correction device of an image display device that combines vertical and horizontal parabola waveforms to a cathode current indicating brightness imbalance between right and left and up and down of a CRT to correct the brightness of the screen.

As shown in FIG. 1, the luminance adjusting device of the conventional image display apparatus includes a parabolic generator 11 for outputting vertical and horizontal parabola waves corresponding to input vertical and horizontal synchronous signals, and the parabolic generator 11. First and second amplifiers 12 and 13 for amplifying and outputting the vertical and horizontal parabola waves outputted by the variable resistors VR1 and VR2 at the amplification factor set by the variable resistors VR1 and VR2, and the input image signal RGB. Amplified output through the image amplifier 14 while varying according to the amplification ratio of the image amplifier 14 and the first and second amplifiers 12, 13 to amplify and output to the CRT (15). It is composed of a variable resistor VR3 for adjusting the amplification factor of the video signal RGB to be used. Herein, reference numerals R1 to R4 are resistors.

The operation of the brightness adjusting device of the conventional video display device configured as described above will be described with reference to FIGS. 1 and 2.

First, when the vertical synchronizing signal and the horizontal synchronizing signal are input to the parabola generator 11, the parabolic generator 11 corresponds to the vertical and horizontal synchronizing signals as shown in FIG. Outputs parabola waves.

At this time, the vertical parabola wave output from the parabola generator 11 is smoothed in the condenser C1 and output to the negative terminal of the first amplifier 12, and the negative terminal of the first amplifier 12 is negative. The amplified vertical parabola wave is amplified by the amplification factor set by the variable resistor VR1 and output to the capacitor C3.

In addition, the horizontal parabola wave output from the parabola wave generator 11 is smoothed in the condenser C2 and output to the negative terminal of the second amplifier 13, and negative in the second amplifier 13. The horizontal parabola wave inputted to the terminal is amplified by the amplification factor set by the variable resistor VR2 and output to the condenser C3.

In the condenser C3, the vertical parabola waves and the horizontal parabola waves amplified and output by the first and second amplifiers 12 and 13 are superimposed, and at the same time with the direct current voltage A by the power source B ⁺ . Overlapping is performed, and the waveform as shown in FIG. 2C is input to the image amplifier 14.

In this case, in the image amplifier 14, the amplified RGB signal is amplified according to the amplification ratios of the first and second amplifiers 12 and 13, and the variable resistor VR3 is amplified by overlapping vertical and horizontal parabola waves. By adjusting the amplification rate, the brightness of the screen is corrected by further amplifying the image signal RGB to be displayed at each corner rather than the center of the screen.

However, in the brightness adjusting device of the conventional video display device, the amplification ratio of the image amplifier is adjusted through the waveforms in which the vertical parabola waves and the horizontal parabola waves overlap, thereby amplifying and reproducing the image signal to be reproduced at the corner rather than the center of the screen. The brightness of the top, bottom, left and right screens could not be corrected only by adjusting the brightness between the part and the corner part.

Therefore, the present invention clamps the parabola composite signal synthesized with the horizontal parabola waveform in the vertical parabola waveform to solve the conventional problems as described above, and outputs the preamplifier. Thus, the vertical parabola waveform corrects the brightness above and below the screen and the horizontal parabola. The main purpose is to provide the user with clear picture quality and to improve the product quality by correcting the brightness of the screen left and right by the waveform.

1 is a block diagram showing the configuration of a luminance adjusting device of a conventional video display device;

2 (a) to (c) are each sub-output waveform diagram of a conventional video display device.

3 is a block diagram showing the configuration of a luminance correction device of an image display device of the present invention;

4A to 4D are waveform diagrams of the sub-outputs of the video display device of the present invention.

5 is a circuit diagram of a clamp control unit of the present invention.

6 is a view showing an output screen by the luminance correction device of the present invention;

As shown in FIG. 3, the configuration of the luminance correcting apparatus of the image display apparatus for achieving the above object includes a parabola synthesizer 21 for synthesizing vertical and horizontal parabola waves corresponding to vertical and horizontal synchronous signals. A clamp control unit 22 for clamping the parabola composite signal by the parabola synthesis unit 21 by DC voltage DC by gain control, and a preamplifier for amplifying the input image signal RGB microscopically. 23) and a main amplifier 24 for main amplifying the video signal amplified by the preamplifier 23 and outputting the amplified video signal to the CRT.

The operation of the luminance correction device of the image display device of the present invention configured as described above will be described with reference to FIGS. 3 to 6.

First, vertical and horizontal parabolas such as (a) of FIG. 4 corresponding to vertical and horizontal synchronous signals are input to the parabola compounding unit 21, and the vertical parabola wave input from the parabola compounding unit 21 is input. A horizontal parabola wave is synthesized in the inside, and a parabola composite signal as shown in FIG.

At this time, the clamp control unit 22 clamps the parabola composite signal by the DC voltage DC by the gain control and outputs it to the preamplifier 23.

As an example, as shown in FIG. 5, the parabola composite signal generated by the parabola synthesis unit 21 is applied to the capacitor C1 of the clamp control unit 22 including the capacitor C1, the diode D1, and the resistor R1. The parabola composite signal smoothed and output from the capacitor C1 is clamped by the DC voltage DC by the gain control through the diode D1 and the resistor R1, thereby preamplifying the preamplifier 23 and the main amplifier ( It is output to the cathode output terminal via 24).

On the other hand, the image signal RGB is amplified through the preamplifier 21 and the main amplifier 22 and then output to the cathode output stage. At this time, the parabola composite signal clamped and output by the clamp control unit 22 is a preamplifier ( 21) and the luminance amplification of the image signal amplified by the main amplifier 22 and output to the cathode output terminal is corrected and displayed on the CRT screen.

That is, as shown in FIG. 6, the vertical parabola waveform brightens the image signals displayed on the upper and lower screens, thereby correcting the brightness of the upper and lower screens, and the horizontal parabola waveform brightens the image signals displayed on the left and right screens. Since the luminance at the left and right sides is corrected, the luminance of the entire screen is uniform.

The brightness correction device of the image display device of the present invention that acts as described above corrects the brightness of the upper and lower screens by the vertical parabola waveform, and corrects the brightness of the left and right screens by the horizontal parabola waveform so that the brightness of the entire screen is uniform. It has the effect of providing clear picture quality and improving product quality.

Claims (2)

The parabola synthesizing unit 21 for synthesizing the vertical and horizontal parabola waves corresponding to the vertical and horizontal synchronizing signals, and the parabola synthesizing signal by the parabola synthesizing unit 21 are clamped by the DC voltage DC by gain control. A pre-amplifier 23 which micro-amplifies the input image signal RGB, and an image signal amplified by the pre-amplifier 23 and outputs the amplified image to the CRT 25. Luminance correction apparatus for a video display device, characterized in that the main amplifier 24. The method of claim 1, wherein the clamp control unit 22 is composed of a capacitor (C1), a diode (D1) and a resistor (R1), the parabola compound 21 is connected to one side of the capacitor (C1) and the diode ( D1) and a DC voltage (DC) is applied to one side of the resistor (R1) to clamp the parabola composite signal to output to the preamplifier (23).