KR100314055B1 - Image sharpness controlling circuit for monitor - Google Patents

Abstract

The present invention relates to an image sharpness adjustment circuit of a monitor, and more particularly, to improve the sharpness of an image by detecting a luminance of a primary color signal and adjusting gain and delay time. The present invention for this purpose, in the monitor for scanning the primary color signal (R, G, B) to the screen of the CD (CDT) 230 through the pre-amplifier 210, the main amplifier 220, the brightness control signal A grid voltage adjusting unit 240 for outputting a grid voltage corresponding to the BRT, a mixer 250 for mixing the primary color signals to generate a luminance signal Y, and an output from the mixer 250. The gain and delay control unit 260 extracts the high frequency component by amplifying the signal to a predetermined gain and then differentiates the modulated signal by adding the output signal of the gain and delay control unit 260 and the output signal of the grid voltage adjusting unit 240. The adder 270 for supplying a grid bias voltage to the grid terminal G1 of the CDT 230, and the gain and derivative time constant of the gain and delay control unit 260 according to a user's key input. It consists of the microcomputer 290 to adjust.

Description

Image sharpness adjustment circuit of monitor {IMAGE SHARPNESS CONTROLLING CIRCUIT FOR MONITOR}

The present invention relates to a monitor, and more particularly to an image sharpness adjustment circuit.

As shown in the block diagram of FIG. 1, the image circuit of the conventional monitor includes a preamplifier 110 for preamplifying the primary color signals R, G, and B of weak levels, and a video from the preamplifier 110. FIG. According to the main amplifier 120 for amplifying the signal at a predetermined level, the CDT 130 for displaying an image by scanning the video signal from the main amplifier 120 and displaying an image, and the brightness control signal BRT. It is composed of a grid voltage adjusting unit 140 for adjusting the voltage of the grid terminal (G1) of the CD (130).

Referring to the operation of the prior art as follows.

When the image signal RGB is input, the preamplifier 110 is amplified to the extent that signal processing is possible.

Accordingly, when the main amplifier 120 amplifies the video signal from the preamplifier 110 to a predetermined level, the image is displayed by being transmitted to the CD 130 and scanned on the screen.

If the user wants to adjust the brightness of the image, the user presses a specific key and then adjusts the level of the brightness control signal BRT using an arbitrary adjustment button or a variable volume.

In this case, the grid voltage adjusting unit 140 supplies a voltage corresponding to the level of the brightness control signal BRT adjusted by the user to the grid terminal of the CD 130.

Therefore, the brightness of the image displayed on the screen is adjusted by adjusting the amount of the electron beam scanned on the screen of the CD 130.

On the other hand, the sharpness of the image displayed on the screen of the CDT (CDT) 130 is a frequency characteristic and video having a uniform video gain in the low and high frequency bands of the preamplifier 110 and the main amplifier 120 It almost depends on the video pulse response characteristics related to the rise and fall times of the signal.

Therefore, the sharpness of the image is determined by the device performance of the preamplifier 110 and the main amplifier 120 to amplify the video signal.

However, the conventional technique has a disadvantage in that the image clarity can no longer be improved dramatically because the performance improvement of the frequency characteristics and the video pulse response characteristics of the device for amplifying a video signal has reached its limit.

Accordingly, an object of the present invention is to provide an image sharpness adjustment circuit of a monitor invented to improve image sharpness by detecting luminance of a primary color signal and adjusting gain and delay time in order to improve a conventional problem. .

1 is a block diagram of a video circuit of a conventional monitor.

2 is a block diagram of a circuit according to an embodiment of the present invention.

3 is a detailed block diagram of a mixer and a gain and delay control in FIG.

FIG. 4 is a waveform diagram of an output signal of the gain and delay controller of FIG. 2. FIG.

Explanation of symbols on the main parts of the drawings

210,220,261: Amplifier 230: CDT

240: grid voltage adjusting unit 250: mixer (MIXER)

251 to 253: multiplier 254,270: adder

260: gain and delay control unit 262: differentiator

280: key input section 290: microcomputer

The present invention provides an image sharpness adjusting circuit of a monitor including a grid voltage adjusting unit for supplying a grid voltage of a CD displaying an image in order to achieve the above object. A mixer for generating the?), A gain and delay control unit for amplifying the output (Y) of the mixer with a predetermined gain, and then demultiplexing and extracting a high pass component, and a high pass signal and brightness in the gain and delay control unit An adder for supplying a grid bias voltage to the grid terminal of the CDT by summing and modulating a grid terminal voltage in the grid voltage adjusting unit corresponding to a control signal, and according to a user's key input, And a microcomputer for adjusting the adjustment gain and differential time constant.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 2 is a block diagram of a device showing an embodiment of the present invention, as shown therein, a preamplifier 210 for preamplifying primary color signals R, G, and B of a weak level, and the preamplifier 210. FIG. Main amplifier 220 for amplifying the video signal at a predetermined level, a CDT 230 for scanning the video signal from the main amplifier 220 on a screen, and displaying it as an image, and a brightness control signal ( A mixer 250 for generating a luminance signal Y by mixing the grid voltage adjusting unit 240 for outputting a grid terminal voltage corresponding to the BRT and the primary color signals R, G, and B at a predetermined ratio. A gain and delay control section 260 for amplifying the output signal Y from the mixer 250 with a predetermined gain and differentiating and extracting a high frequency component; and an output signal of the gain and delay control section 260, and Grid bias voltage by adding and modulating the output signal of the grid voltage adjustment unit 240 The adder 270 for supplying the grid terminal G1 of the CDT 230 and the adjustment gain of the gain and delay control unit 260 as the user selects and adjusts a specific key of the key input unit 280. And a microcomputer 290 for adjusting the differential time constant.

The mixer 250 and the gain and delay control unit 260 are configured as shown in the block diagram of FIG.

The mixer 250 adds multipliers 251 to 253 for multiplying the primary color signals R, G, and B by a predetermined gain, and outputs the output signals of the multipliers 251 to 253 to obtain a luminance signal Y. The adder 254 outputs.

The gain and delay control unit 260 is an amplifier 261 for adjusting the gain of the output signal (Y) of the mixer 250 by the control of the microcomputer 290, and the derivative by the control of the microcomputer 290 The time constant is adjusted to constitute a differentiator 262 which extracts a high frequency component by differentiating the output signal of the amplifier 261.

The differentiator 262 may include an electronic variable resistor and a capacitor.

Referring to the operation and effect of the embodiment of the present invention configured as described above are as follows.

When the image signal RGB is input, the level of the image signal is weak enough to process the signal, so that the preamplifier 210 amplifies the signal to a level sufficient for signal processing.

Accordingly, when the main amplifier 220 amplifies the video signal from the preamplifier 210 to a predetermined level, the image is displayed by being transmitted to the CD 230 and scanned on the screen.

If the brightness of the image is adjusted, the conventional technique is performed by outputting only the output voltage (DC voltage) from the grid voltage adjuster 240 to the grid voltage terminal of the CD 230 without operating the gain and delay controller 260. Can be operated in the same way as

In addition, when the user wants to adjust the sharpness of the image, the user presses a specific function key in the key input unit 280 and then selects and adjusts an arbitrary adjustment button so that the microcomputer 290 gains or times the gain and delay control unit 260. The delay amount is adjusted.

In this case, the grid voltage adjusting unit 240 outputs a grid terminal voltage corresponding to the level of the brightness control signal BRT, and the output voltage is supplied to the grid terminal G1 of the CD 230 through the adder 270. Lose.

The mixer 250 outputs the luminance signal Y to the gain and delay control unit 260 by multiplying and adding the respective gains to the input image signals R, G, and B, respectively.

That is, in the mixer 250, the multipliers 251 to 252 multiply predetermined values (0.3, 0.6, and 0.1) with respect to each of the image signals R, G, and B, and the adder 254 multiplies the respective multiplication values. The sum is outputted to the gain and delay control unit 260 of the luminance signal (Y = 0.6G + 0.3R + 0.1B).

Accordingly, the gain and delay control unit 260 causes the amplifier 261 to amplify the output signal Y from the mixer 250 by a predetermined gain, and the differentiator 262 differentiates the amplified signal to a predetermined time constant to obtain a high range. By extracting the components, a high frequency component signal GD such as the waveform diagram of FIG. 4 is input to the adder 270. The amplification gain and derivative time constant are selected by the user in the key input unit 280. As the adjustment is made, the microcomputer 290 adjusts.

The differentiator 262 may be configured using an electronic variable resistor and a condenser. The differential time constant is adjusted by changing the variable resistance value under the control of the microcomputer 290.

In this case, the adder 270 inputs the grid bias voltage G1 to the grid terminal of the CD 230 by modulating the output signal of the grid voltage adjusting unit 240 and the output signal of the gain and delay control unit 260. Let's go.

Therefore, the scan amount of the electron beam is controlled in the CD 230 which receives the output voltage of the adder 270 through the grid terminal G1, thereby improving the sharpness of the image.

That is, the signal supplied to the grid terminal of the CD 230, the gain is adjusted to the brightness signal (DC voltage) as in the prior art, and the brightness signal (Y) from which the high-pass component is extracted is combined, the image sharpness state of the screen It is adjusted by the user's choice.

For example, in the present invention, the blurring phenomenon of the image is unobtrusive in the case of the window screen or the text screen, and the gain of the high frequency component is largely adjusted, and the differential time constant is small, thereby increasing the difference in contrast to improve the sharpness of the image. .

In the present invention, in the case of a moving picture (MPEG) or a still picture (JPEG), by increasing the differential time constant of the high frequency component, the blurring phenomenon of the image is increased to improve the sharpness of the image.

In other words, when the gain is increased in the waveform diagram of FIG. 4, the difference in contrast increases, and when the differential time constant is increased, the blurring phenomenon of the image increases.

In the above-described operation, the gain and delay control unit 260 adjusts the gain and then differentiates it to extract a high frequency component. On the contrary, the high frequency component may be extracted and then the gain of the high frequency component may be adjusted.

As described in detail above, the present invention adjusts the gain of the luminance signal from the primary color signal or adjusts the derivative time constant at the time of extracting the high frequency component to further increase the brightness difference of contrast and the degree of smear of the image. By adjusting, the sharpness of the image can be improved.

Claims (2)

An image sharpness adjusting circuit of a monitor having a grid voltage adjusting unit for supplying a grid voltage of a CD displaying an image of a primary color as an image, comprising: a mixer for generating a luminance signal Y by mixing primary colors at a predetermined ratio And a gain and delay control unit for amplifying the output Y of the mixer with a predetermined gain and then demultiplexing to extract the high frequency component, and the grid corresponding to the high frequency component signal and the brightness control signal of the gain and delay control unit. An adder for supplying a grid bias voltage to the grid terminal G1 of the CDT by summing and modulating the grid terminal voltages in the voltage adjusting unit, and for adjusting the gain and derivative time constant of the gain and delay control unit. An image sharpness adjustment circuit of a monitor comprising a control means. The image sharpness adjusting circuit of a monitor according to claim 1, wherein the control means is configured to adjust a gain of the high frequency component in the case of a window screen or a text screen, and adjust a derivative time constant of the high frequency component in the case of a moving image or a still image. .