KR100190975B1 - Automatic brightness control method of a television receiver - Google Patents

Abstract

The present invention detects the level of the ABL signal for a certain period of time when the television receiver or monitor is used, in particular, when the brightness changes suddenly, and automatically adjusts the video output adjustment level such as brightness, contrast, and tint of the screen to watch. It is an object of the present invention to provide a method for automatically adjusting the brightness of the screen of a television receiver to prevent a person from accumulating a lot of eyes.

The method according to the present invention for achieving the above object comprises the steps of: setting an automatic surface state change mode for searching whether the automatic surface state change mode is selected while the power of the television receiver is driven; When the automatic surface state change mode is set, if the brightness of the screen suddenly changes within a predetermined time, it is characterized in that the automatic surface state change process of informing the user and down the brightness of the screen.

Description

How to automatically adjust the brightness of the television set

1 is a configuration diagram of a cathode ray tube driving apparatus in a conventional television receiver.

2 is a schematic block diagram of a television receiver for implementing the present invention.

3 is a flowchart of an automatic adjustment process of a television receiver according to the technique of the present invention.

* Explanation of symbols for the main parts of the drawings

202 tuner 206 image detector

210: image processing unit 211: image output unit

213: cathode ray tube 215: microprocessor

216: PWM generator 217: integral circuit

220: anode 221: ABL current level detector

222: analog / digital converter 224: OSD generator

225: Timer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver, and more particularly, when a television receiver or a monitor is used, a state of a screen, for example, a sudden change in brightness, is detected for a brightness, contrast, and tint of a screen. The present invention relates to a method for automatically adjusting screen brightness of a television receiver to automatically adjust a video output adjustment level such as (Tint) to prevent viewers from accumulating much eyes.

In general, the high-resolution output of a flyback transformer (FBT) is used depending on the resolution and brightness of a television set or monitor. The flyback transformer uses a rapid current change in the return period of the horizontal deflection current. It generates high voltage pulse and it is used as high voltage source of anode (anode) of cathode ray tube to convert screen brightness.

The high voltage generated by the flyback transformer and supplied to the anode of the cathode ray tube is typically 25KV to 30KV, and is supplied immediately upon turning on the power switch of the television set and the monitor set to drive the cathode ray tube. .

FIG. 1 is a configuration diagram of a cathode ray tube driving apparatus in a conventional television receiver. As shown therein, a horizontal deflection portion generating horizontal pulses for driving the cathode ray tube 106 according to an input horizontal synchronous H ( 100); A capacitor which is switched according to a horizontal pulse provided from the horizontal deflection unit 100 to resonate a low DC voltage (B ⁺ ) generated and input from a low voltage rectifier (not shown) and corrects an S curve of the resonance voltage ( C2) and an input pulse portion 101 composed of a resonant capacitor C1, a damping diode D1, a transistor Q1, and a horizontal deflection coil L1 which form a series of resonant circuits with the capacitor C2; A flyback transformer 103 which receives the resonance voltage generated by the input pulse unit 101 through the primary coil L1 and excites a high voltage to the secondary coil L2; The high voltage generated by the flyback transformer 103 is rectified through the diode D4, smoothed through the capacitor C5, and supplied to the anode 106a of the cathode ray tube 106, and also through the diode D4. A high-voltage rectifier 104 for dividing the rectified voltage through resistors R1 and R2 and outputting the divided voltage; The on / off control of the transistor Q2 is controlled according to the voltage divided by the resistors R1 and R2 of the high voltage rectifying unit 104 and the diode D2 according to the on / off control of the transistor Q2. Resonance voltage compensation unit 102 for boosting and lowering the resonance voltage supplied to the primary coil L1 of the flyback transformer 103 by the combined capacitance values of the capacitors C3 and C4 by (D3). Wow; An image output unit 105 for processing an input image signal as primary color signals R, G, and B and outputting the same; A deflection yoke for deflecting the electron beams for the primary color signals R, G, and B generated by the image output unit 105 in the horizontal and vertical directions due to horizontal and vertical sawtooth wave currents and displaying them on the fluorescent surface of the cathode ray tube 106. It consists of 107.

As described above, in the conventional cathode ray tube driving apparatus of the conventional television receiver, when the main power switch of the television receiver is turned on, the horizontal synchronization signal H for the composite synchronization signal is detected by the synchronization detection means (not shown) and the horizontal deflection is performed. It is provided to the part 100.

The horizontal deflection unit 100 waveform-forms and amplifies the input horizontal synchronization signal H, generates a horizontal pulse signal corresponding thereto, and provides it to the base of the transistor Q1 configured in the input pulse unit 101.

Since the base current of the input pulse unit 101 to the transistor Q1 is driven corresponding to the horizontal pulse signal derived from the horizontal deflection unit 100, the primary coil of the flyback transformer 103 to be described later. (L1), the resonant capacitor (C1) and the damping diode (D1) are brought into a continuous resonance state by the low DC voltage (B ⁺ ) which is rectified and input in the low voltage rectifier.

Accordingly, a large resonance current flows through the primary coil L1 of the flyback transformer 103, and the horizontal deflection coil L1 and the capacitor C2 correct the S curve of the resonance voltage.

The large resonance current applied to the primary coil L1 of the flyback transformer 103 is induced to its secondary coil L2 by an electromagnetic induction effect, and the induced resonance voltage is a diode of the high voltage rectifier 104. Rectified through D4) and smoothed through condenser C5, it is supplied to anode 106a of cathode ray tube 106 at high DC voltage.

On the other hand, the resonant voltage compensator 102 is present between the input pulse unit 101 and the flyback transformer 103 to compensate the secondary high voltage of the flyback transformer 103 is detected by the high voltage rectifier 104 The combined capacitance values of the capacitors C3 and C4 by the diodes D2 and D3 are selected in accordance with the transistor Q2 controlled by the signal and the on / off control of the transistor Q2.

For example, when the transistor Q2 of the resonance voltage compensator 102 is connected by the high voltage detection signal of the high voltage rectifying unit 104 by the resistance R1 and the voltage divider resistor R2 or more, the resonance voltage compensator 102 ) Is determined by the value of the capacitor (C3) only, and the resonant frequency is changed through the combined capacitance of the capacitor (C3) and the resonant capacitor (C1) of the input pulse unit 101 is output from the high-voltage rectifier (104) The high DC voltage supplied to the anode 106a of the cathode ray tube 106 is lowered.

On the contrary, in the case of a high voltage detection signal below the normal value by the high voltage rectifying unit 104, the transistor Q2 of the resonance voltage compensating unit 102 is cut off, and thus the synthesized capacitance of the resonance voltage compensating unit 102 is the capacitor C3. ) Is determined by the series connection circuit of (C4), and the synthesized capacitance and the capacitance of the resonant capacitor C1 of the input pulse unit 101 are synthesized so that the resonant frequency is greatly changed. The high DC voltage supplied to the anode 106a of the tube 106 is increased to stabilize the resolution of the cathode ray tube 106.

As such, the cathode ray tube 106 driven by the high DC voltage output from the flyback transformer 103 deflects the primary color signals R, G, and B of the image output unit 105 due to the input image signal. The display is displayed on the fluorescent screen by the horizontal and vertical deflection of 107, thereby determining the brightness of the screen.

When the main power switch of the television receiver is turned off, the driving of the flyback transformer 103 is stopped, and a DC high voltage of 25 KV to 30 KV remains for a predetermined time on the anode 106a side of the cathode ray tube 106. Over time, the residual high voltage disappears.

However, as described above, the cathode ray tube driving apparatus of the conventional television receiver controls the secondary high voltage of the flyback transformer according to the high and low voltage supplied to the anode of the cathode ray tube to adjust the resolution and brightness of the screen. There is a problem that the viewer watching a lot of fatigue when the brightness of the screen suddenly changes several times within a short time to give a function only.

Therefore, the present invention has been made to improve the above-described problems of the prior art, and when using a television receiver or a monitor, the brightness of the screen by detecting the level of the ABL signal when the state of the screen, for example, the brightness suddenly changes for a certain time, It is an object of the present invention to provide a method for automatically adjusting screen brightness of a television receiver to automatically adjust a video output adjustment level such as contrast and tint to prevent a viewer from accumulating a lot of eyes.

The method according to the present invention for achieving the above object comprises the steps of: setting an automatic surface state change mode for searching whether the automatic surface state change mode is selected while the power of the television receiver is driven; When the automatic surface state change mode is set, if the brightness of the screen suddenly changes within a predetermined time, it is characterized in that it consists of an automatic surface state change process to notify the user and down the brightness of the screen.

The automatic surface state change process may include detecting an ABL signal level in response to detecting an automatic surface state change mode setting; Operating a timer in addition to detecting the ABL signal level; Searching whether the ABL signal level repeats more than a set upper and lower limit for a time set by the timer; OSD warning through a screen when the ABL signal level is repeated above a set upper and lower limit; Lowering the level of brightness of the screen with the OSD alert; Maintaining a normal screen state when the automatic screen state change mode is released after the brightness of the screen is down. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of an automatic screen brightness adjusting device of a television receiver for implementing the present invention. As shown therein, a channel up / down function, a volume up / down function, and an on / off time of a television receiver are shown by a user. A remote controller 213 which selects a setting, a channel setting, a menu screen, an automatic screen state control function, and sends an infrared signal to the selected function key; A remote control receiver 214 for receiving an infrared signal transmitted from the remote controller 213 and digitizing and outputting the infrared signal; A microprocessor (215) for controlling each part of the system by detecting a function selection signal of the user output from the remote control receiver (214); Amplified a high frequency (RF) signal received from the antenna 201 according to the control signal output from the microprocessor 215, and converts a frequency to convert the complex intermediate frequency (IF) signal to tune to a broadcast channel selected by the viewer. A tuner 202 for detecting and outputting; An intermediate frequency amplifier 203 for amplifying and outputting a complex intermediate frequency signal of a corresponding broadcast channel output from the tuner 202 to a predetermined level; A video / audio (P / S) separator 204 for separating the complex intermediate frequency signal amplified by the intermediate frequency amplifier 203 into an image and an audio intermediate frequency signal; A voice detector 205 which detects the 4.5 MHz audio intermediate frequency signal from the video / audio (P / S) separation unit 204 and restores the original audio signal; A voice processor 207 for processing a base, treble, volume, etc. and outputting the voice signal detected and input by the voice detector 205; A voice amplifier 208 for low frequency amplifying the voice signal output from the voice processor 207 and outputting the voice signal through the speaker 209; An image detector 206 for detecting an image intermediate frequency signal from the image / audio separator 204 and restoring and outputting the original image signal; Under the control of the microprocessor 215, an OSD (On Screen Display) character for displaying a selection state such as a channel selected by a user, an automatic surface state control function, etc. is displayed on the screen and outputted from the OSD font ROM 224. An OSD generator 223; Adjust brightness, contrast, tint, etc. of characters and video signals output from the OSD generator 223 or the image detector 206 according to the control of the microprocessor 215. An image processor 210 for outputting; An image output unit 211 which scans the image signal (R, G, B) signal and outputs the image signal to the cathode ray tube 213 from the image signal output from the image processor 210; An ABL current level detector 221 for detecting the ABL current level output from the anode 220 which changes according to the brightness of the image signal displayed through the cathode ray tube 213; An analog / digital (A / D) converter 222 for converting an analog signal output from the ABL current level detector 221 into a digital signal and outputting the digital signal to the microprocessor 215; PWM for generating a predetermined pulse width modulation (Plus PWM) signal of a control signal of the microprocessor 215 that senses the ABL current level output from the analog / digital conversion unit 222. A generator 216; The integrated circuit unit 217 integrates the corresponding PWM signal output from the PWM generator 216 and outputs the integrated signal to the image processor 210.

Here, reference numeral 212 indicates that the electron beams for the primary color signals R, G, and B generated by the image output unit 211 are deflected in the horizontal and vertical directions due to the horizontal and vertical sawtooth wave currents of the cathode ray tube 213. A deflection yoke displayed on the fluorescent surface, 225 is a timer 225 for supplying time under the control of the microprocessor 215.

Referring to the preferred embodiments of the present invention configured as described above with reference to Figures 2 and 3 as follows.

3 is a flowchart of a process of automatically adjusting screen brightness of a television receiver according to the present invention. As shown in the drawing, when a user first drives the power of the television receiver through the remote controller 213, the remote controller receiver 214 detects this. The microprocessor 215 detects it and controls each part of the system to perform a television reception mode.

That is, the tuner 202 detects and amplifies a high frequency signal of a predetermined channel through the antenna 201 under the control of the microprocessor 215, detects the corresponding complex intermediate frequency signal, and outputs the complex intermediate frequency signal to the intermediate frequency amplifier 203. .

The intermediate frequency amplifying unit 203 amplifies the detected intermediate frequency signal to a predetermined level, and the audio intermediate frequency signal is the audio detector 205 and the image intermediate frequency signal is detected by the image / audio separation unit 204. It is output to the unit 206 and processed through the respective audio and image processing units 207 and 210, and then outputs audio and image through the speaker 209 or the cathode ray 213.

At this time, when the user selects the automatic surface state control mode, the microprocessor 215 detects this to operate the timer 225 and drives the ABL current level detector 221 to the anode 220 of the cathode ray tube 213. Detects the level of the ABL current and converts it into a digital signal through the analog / digital converter 222 and outputs it to the microprocessor 215.

At this time, the microprocessor 215 receives the set time from the timer 225 and detects when the ABL current output from the analog / digital converter 222 repeats more than a predetermined upper and lower limits within a set time. By controlling the PWM generator 216 to lower the brightness level of the current screen.

Meanwhile, the microprocessor 215 controls the OSD generator 224 to detect whether the brightness is adjusted according to the result detected by the user, and detects the corresponding character from the OSD font ROM 223 and outputs it to the image processor 210. .

That is, the PWM generator 216 receives the control signal from the microprocessor 215 and downs the brightness by the corresponding level to generate the corresponding PWM signals such as brightness, contrast, and tint.

The signal output from the PWM generator 216 is output to the respective terminals Bri, Cont, and Tint of the image processor 210 through the integration circuit 217.

The image processor 210 outputs the text data output from the OSD generator 224 to the image output unit 211 and displays the text data on the screen through the cathode ray tube 213 and outputs from the integrator circuit 217. The image signal output from the image detector 206 is adjusted according to the brightness, contrast, tint, and the like, and is output to the image output unit 211.

As such, the image signal whose brightness is adjusted in the image processor 210 displays the image output signals R, G, and B on the screen through the cathode ray tube 213 in the image output unit 211.

As described above, the present invention senses the level of the ABL signal when the state of the screen, especially the brightness, changes suddenly when using a television receiver or a monitor to adjust the level of image output control such as brightness, contrast, tint, etc. of the screen. It automatically adjusts to prevent viewers from accumulating much fatigue in their eyes. And while certain embodiments of the invention have been described and illustrated, it will be appreciated that the invention is not so limited, as various modifications are possible.

It is therefore to be understood that the invention and all modifications which come within the true spirit and scope of the principles described and claimed herein may be covered.

Claims (1)

Detecting the ABL signal level according to the automatic surface state change mode setting, operating the timer together with detecting the ABL signal level, and whether the ABL signal level repeats more than the set upper and lower limits for a time set by the timer. Searching, and if the ABL signal level is repeated above the set upper and lower limits, OSD warning through the screen, down the brightness of the screen with the OSD warning, and lowering the brightness of the screen If the automatic screen state change mode after the step of maintaining the normal screen state, characterized in that the automatic adjustment of the screen brightness of the television receiver.