KR19980057447U - Display brightness adjustment circuit of display device - Google Patents

Abstract

The present invention obtains an average voltage level from the R (red), G (green), and B (blue) video signals of the display device, adds them according to the brightness ratios of R, G, and B, and adds them according to the added voltage level. It relates to a screen brightness adjustment circuit of the display device for adjusting the brightness.

Input preamplifier and amplification unit for receiving and amplifying synthesized R, G, and B signals and outputting them to CRT, CRT for visually implementing the amplified image, external control signal, horizontal synchronization signal and vertical synchronization signal A microcomputer for receiving and controlling each component of the display device, a deflector for outputting a horizontal deflection sawtooth current and a vertical deflection sawtooth current for horizontal deflection and vertical deflection using horizontal and vertical synchronization signals, and a preamplifier It is composed of an integrating and adding circuit which receives the R, G and B signals outputted from and obtains an average voltage level and adds it according to the brightness ratio of R, G and B, and adds the added voltage level to the microcomputer. The screen brightness of the display device may be kept constant.

Description

Display brightness adjustment circuit of display device

The present invention obtains an average voltage level from the R (red), G (green), and B (blue) video signals of the display device, adds them according to the brightness ratios of R, G, and B, and adds them according to the added voltage level. It relates to a screen brightness adjustment circuit of the display device for adjusting the brightness.

In general, in order to control the brightness of the display device, the brightness of the screen is controlled by adjusting a switch and an adjustment volume exposed to the outside of the display device or by inputting a screen brightness control command with an input device such as a keyboard. The brightness of the screen varies according to the level of the input video signal and the area of the image displayed on the screen.

For example, if you print the entire screen in white and if you print a small white square box on the screen, the screen brightness is different.

When the entire screen is printed in white, the current consumption is greater than when a small white square box is printed on the screen, and the brightness of the screen is relatively darker.

Therefore, in the conventional display device, the brightness of the screen or the pixel is changed according to the width of the area displayed on the screen of the video signal and the ratio of R, G, and B, so that the user cannot easily obtain a screen of constant brightness, which makes the user's eyes easily tired. There was a problem that the brightness of the screen was not stable.

Accordingly, an object of the present invention is to provide a screen brightness adjusting circuit of a display device such that the screen maintains a constant brightness regardless of the width of the area where the video signal is displayed on the screen and the ratio of R, G, and B.

The object of the present invention as described above, the average voltage level is obtained by the integration and addition circuit for the R, G, B signals varying with time, added to the brightness ratio of R, G, B, and then input to the microcomputer, The microcomputer achieves this by comparing the applied voltage level with the reference voltage at regular intervals, calculating a correction value of the screen brightness, and controlling to output the correction value.

1 is a block diagram schematically showing a screen brightness adjusting circuit of a display device according to the present invention;

2 is a circuit diagram showing in detail the integration and addition circuit of FIG.

3 is a flowchart illustrating an operation of a microcomputer to control screen brightness adjustment of a display device.

* Explanation of symbols used in the main part of the drawing

10: preamplifier

11: amplifier

12: CRT

13: microcomputer

14: deflection

15: Integral and Addition Circuit

20: integral part

21: addition unit

C1, C2, C3: Condenser

OP: Operational Amplifier

R11, R21, R31, R12, R22, R32, R4: Resistor

Hereinafter, a preferred embodiment of the screen brightness adjustment circuit of the display device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram schematically illustrating a screen brightness adjusting circuit of a display device according to the present invention. The preamplification unit 10 and the amplifying unit 10 receive and amplify a synthesized R, G, and B signal and output the result to a CRT. 11), a CRT 12 which visually implements the image amplified by the amplifier 11, a micro that receives an external control signal, a horizontal synchronization signal and a vertical synchronization signal and controls each component of the display device accordingly. A computer 13, a deflection portion 14 for outputting a horizontal deflection sawtooth current and a vertical deflection sawtooth current for horizontal and vertical deflection in accordance with the horizontal and vertical synchronization signals output from the microcomputer 13; Receives the R, G, and B signals output from the preamplifier 10, obtains average voltage levels, adds them according to the brightness ratio of R, G, and B, and adds the added voltage levels to the microcomputer 13. doing It consists of an integration and addition circuit 15.

FIG. 2 is a circuit diagram showing the integration and addition circuit 15 in detail. The integrator 20 includes resistors R11, R21, and R31 and capacitors C1, C2, and C3, and resistors R12, R22, It can be broadly divided into an adder 21 composed of R32 and another resistor R4 and an operational amplifier OP.

The integration and addition circuit 15 has R, G, and B signals input from the preamplifier 10 connected to one side of the resistors R11, R21, and R31, respectively, and each of the resistors R11, R21, and R31. The other side of is connected to another resistor (R12, R22, R32), the ground capacitor (C1, C2, C3) is connected between the resistors (R11, R21, R31) and resistors (R12, R22, R32), respectively. do.

The other side of the resistors R12, R22, and R32 are input to the non-inverting input terminal of the operational amplifier OP, the inverting input terminal of the operational amplifier OP is grounded, and the resistors R12, R22, R32 and the operational amplifier are Another resistor R4 is connected between the contact a between OP and the output of the operational amplifier OP.

The R, G, and B signals output from the preamplifier 10 are integrated by the integrator 20 composed of the resistors R11, R21, and R31 and the capacitors C1, C2, and C3, and then the resistors R12, It is added to the operational amplifier OP through R22 and R32 and added. When the values of the resistors R12, R22 and R32 vary depending on the brightness ratio of R, G and B, they are added from the operational amplifier OP. The output voltage value eventually depends on the brightness ratio of R, G, and B.

Looking at the operation of the screen brightness adjustment circuit of the display device having the configuration described above, the synthesized R, G, B signals are amplified by the pre-amplifier 10 and the amplifier 11 is output to the CRT 12 .

On the other hand, a horizontal synchronizing signal and a vertical synchronizing signal are input to the microcomputer 13, and under the control of the microcomputer 13, the horizontal deflection sawtooth current and the vertical deflection sawtooth current are output to the CRT 12. To adjust the deflection of the electron beam.

The R, G, and B signals amplified by the preamplifier 10 are input to the integrating and adding circuit 15, and in the integrating and adding circuit 15, the average voltage levels of the R, G, and B signals input. Calculate and add according to the brightness ratio of R, G, and B.

The added voltage level is input to the analog digital conversion input terminal of the microcomputer 13 and converted into digital. The microcomputer 13 compares the applied voltage level with a predetermined reference voltage at predetermined time intervals, and then compares it. According to the result, a correction value for adjusting the brightness of the screen is applied to the control terminal of the amplifier 11.

3 is a flowchart showing the operation of the microcomputer 13 for controlling the screen brightness adjustment of the display device, in which the added voltage levels of the R, G, and B signals from the integration and addition circuit 15 are reduced to the microcomputer 13. When the input signal is input to the analog digital conversion input terminal (S10), it is determined whether the input voltage level is smaller than the minimum value of the reference voltage range preset for the brightness of the screen (S11).

When the voltage level input in the step S11 is smaller than the minimum value of the reference voltage range, the brightness of the screen is adjusted by increasing the voltage level so as to fall within the reference voltage range (S12), and the brightness of the adjusted screen is controlled by the control terminal of the amplifier. After outputting (S13), a series of processes are ended, and if it is determined that the input voltage level is not smaller than the minimum value of the reference voltage range, it is again determined whether it is greater than the maximum value of the reference voltage range (S14).

If the input voltage level is not greater than the maximum value of the reference voltage range in the step S14, the input voltage level is within the reference voltage range, so that the brightness of the screen is the reference voltage range (S15) and is output to the control terminal of the amplifier. (S13).

If the voltage level input in the step S14 is greater than the maximum value of the reference voltage range, the voltage level is adjusted to fall within the reference voltage range to adjust the brightness of the screen (S16), and output the brightness of the screen to the control terminal of the amplifier. After (S13) a series of processes are terminated.

As described above, according to the screen brightness adjustment circuit of the display device according to the present invention, the screen brightness of the display device can be kept constant regardless of the area of the area where the video signal is displayed on the screen or the ratio of R, G, and B. The brightness of the screen may be changed according to the state of the screen by appropriately selecting the correction value.

Claims (2)

Pre-amplifier and amplification unit for receiving and amplifying the synthesized R, G, B signals and outputting them to the CRT, CRT for visually realizing the image amplified by the amplification unit, perpendicular to the external control signal and the horizontal synchronization signal A microcomputer that receives the synchronization signal and controls each component of the display device accordingly, and a deflection unit that outputs a horizontal deflection sawtooth current and a vertical deflection sawtooth current to horizontally and vertically deflect the electron beam according to the horizontal and vertical synchronization signals. In the configured display device, Integrating and adding circuit which receives R, G and B signals output from the preamplifier, adds the average voltage level according to the brightness ratio of R, G and B, and inputs the added voltage level to the microcomputer. Screen brightness adjustment circuit of the display device characterized in that it comprises. The method according to claim 1, wherein the integration and addition circuit, A brightness ratio of R, G, and B to the first, second, and third integrators for integrating the R, G, and B signals input from the preamplifier, and the output signals of the first, second, and third integrators, respectively. And an adding unit configured to add according to the screen brightness adjusting circuit of the display device.