KR0162199B1 - Brightness correction apparatus of a television - Google Patents

Abstract

The present invention is a device for correcting the magnitude of the luminance signal for the entire screen according to the luminance characteristics of the cathode ray tube by using the same focus signal in order to make the brightness of the screen as a whole uniform, the luminance correction by receiving the same focus signal Means for making a basic signal for the signal, means for receiving the luminance correction signal and the entire luminance signal and synthesizing the signal into a signal having a predetermined average luminance size, and synthesizing the synthesized luminance signal and the image signal to a cathode ray tube; Means are provided so that the brightness of the screen is the same at the center and the edge of the screen by making the magnitude of the luminance signal uniform throughout the screen. In addition, the luminance correction device according to the present invention can be used more effectively in a high resolution screen or a large screen.

Description

TV luminance correction device

1 is a block diagram showing an example of a conventional luminance correction device.

2 is a schematic diagram showing the distribution of luminance over the entire screen.

3 is a circuit diagram showing an embodiment of a luminance correction device according to the present invention.

4 is a waveform diagram showing a dynamic focus signal.

5 is a waveform diagram of a luminance-compensated signal in the apparatus of FIG.

* Explanation of symbols for main parts of the drawings

10: gain adjusting unit 12: parabola signal generating unit

16: cathode ray tube operation unit 18, 38: cathode ray tube

31: luminance correction signal generator 32: reference luminance signal adjustment unit

33: luminance signal synthesizing unit 37: video signal output unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the correction of luminance signals in television signal processing, and more particularly, to a luminance correction apparatus for televisions for correcting luminance signals using dynamic focus signals so that the luminance of the entire screen is uniform.

In general, in a display device using a cathode ray tube such as a television, a phenomenon in which the luminance of the entire screen is not maintained uniformly appears. That is, when the television signal is displanned, the center of the screen is bright and the screen darkens toward the edge. In addition, as the screen is enlarged and the resolution is increased, such unevenness of luminance appears more remarkably. Therefore, a luminance correction device for continuously eliminating the phenomenon in which luminance appears unevenly throughout the screen has been continuously developed.

1 schematically shows a conventional luminance correction device. The apparatus of FIG. 1 is provided with a gain adjusting unit 10 for adjusting the gain of a signal by receiving an image signal Sv, and a parabola signal for appropriately adjusting the magnitude of luminance among the image signals. Since the parabola signal generator 12 to supply, the amplifier 14 for amplifying the gain-adjusted video signal to a predetermined size, and the video signal output from the amplifier 14 are received and displayed on the cathode ray tube, The cathode ray tube operating unit 16 converts and outputs a signal to an appropriate level, and the cathode ray tube 18 displaying an image by receiving the output signal of the cathode ray tube operating unit 16 in an emergency.

In the apparatus of FIG. 1, the parabola signal generator 12 is a means for adjusting the luminance signal on the screen made of the input image signal Sv to have a uniform size throughout the screen. The parabola signal generator 12 receives the horizontal synchronous signal and the vertical synchronous signal of the video signal to set the synchronization pattern, and has a parabola waveform in the vertical and horizontal synchronous periods so that the magnitude of the luminance signal increases toward the edge of the screen. Generate a signal. Then, the gain adjusting unit 10 appropriately adjusts the size of the image signal Sv according to the position of each screen according to the parabola signal supplied from the parabola signal generator 12. That is, the size of the video signal is reduced in the center portion of the screen, and the gain of the video signal is adjusted so as to increase the size of the video signal toward the edge of the screen. The gain-adjusted video signal controls the beam current of the cathode ray tube. That is, as the size of the video signal decreases, the beam current also decreases, and as a result, the brightness of the screen decreases. On the contrary, as the size of the video signal increases, the beam current increases and accordingly the brightness of the screen increases. Therefore, in such a luminance correction device, the beam current can be made smaller with respect to the center portion of the screen, and the beam current can be increased toward the edge to make the luminance of the entire screen uniform.

However, the parabola signal used in the conventional luminance compensator has a problem in that the luminance cannot be adaptively adjusted when the luminance characteristic of the cathode ray tube is changed. That is, when the luminance characteristic of the cathode ray tube is changed, the size of the parabola waveform should be appropriately adjusted accordingly. In the conventional luminance compensator, the parabola signal generator has a problem in that it is difficult to adaptively convert the magnitude of the output parabola signal. Due to this problem, the conventional luminance compensator has a higher screen resolution and a larger screen size. In particular, in a large screen such as a projection screen, the luminance correction for the entire screen is not effectively performed.

Accordingly, an object of the present invention is to provide a luminance correction circuit for maintaining the luminance of the entire screen uniformly by adaptively correcting the magnitude of the image signal according to the luminance characteristics of the cathode ray tube.

The object of the present invention is a luminance correction device for correcting the magnitude of a luminance signal so that the magnitude of the luminance signal is uniform throughout the screen in an apparatus for displaying a composite video signal. A luminance correction signal generator for generating a luminance correction signal for correcting the luminance component by adjusting the size of the input focus signal, and for adjusting and generating a reference luminance signal corresponding to the basic level of the luminance signal magnitude of the entire screen. The luminance signal included in the reference luminance signal adjusting unit, the luminance correction signal output from the luminance correction signal generator, and the luminance signal included in the reference luminance signal and the composite image signal output from the reference luminance signal adjusting unit are supplied to the luminance correction signal and the luminance signal. The luminance signal synthesizing unit and the luminance signal synthesizing unit for synthesizing a signal having a predetermined level by the signal. It is achieved by the brightness correction device including a video signal output for supplying a luminance signal by synthesizing the synthesized image signal with the luminance compensation video signal to the display.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Before describing an embodiment of the present invention, a brief description will be made of a distribution state of luminance over the entire screen as shown in FIG. FIG. 2 (a) shows the luminance distribution before the correction on the luminance signal, and FIG. 2 (b) shows the luminance distribution after the correction on the luminance signal. In FIG. 2 (a), the magnitude of the luminance signal is larger at the center of the screen and smaller at the edge. That is, the magnitude of the luminance signal is not kept uniform throughout the screen. On the other hand, in FIG. 2 (b), the magnitude of the luminance signal has the same value at the center and the edge of the screen. That is, the magnitude of the luminance signal is kept uniform throughout the screen.

3 shows an embodiment of a luminance correction device for television according to the present invention. The apparatus of FIG. 3 includes an input terminal to which the dynamic focus signal DF is input, a luminance correction signal generator 31 for outputting a luminance correction signal by adjusting the magnitude of the dynamic focus signal DF, and a luminance signal of the entire screen. A reference luminance signal adjusting unit 32 for setting a reference value, and a luminance signal synthesizing unit for synthesizing the luminance correction signal output from the luminance correction signal generating unit 31 and the reference luminance signal output from the reference luminance signal adjusting unit 32. (33), the luminance signal amplifier 34, the luminance signal output unit 35, and the image signal amplifier 36 for amplifying and outputting the luminance signal output from the luminance signal synthesis unit 33 to a predetermined size. And a video signal output section 37 for combining the video signal amplified to a predetermined size with the brightness signal output from the brightness signal output section 35 and supplying the brightness correction video signal to the cathode ray tube 38.

The dynamic focus signal DF applied to the input terminal in the apparatus of FIG. 3 removes the DC component while passing through the capacitor C1. The waveform of the dynamic focus signal DF from which the DC component has been removed is shown in FIG. 4. FIG. 4 (a) shows the horizontal dynamic period of the dynamic focus signal DF, and FIG. 4 (b) shows the vertical dynamic period of the dynamic focus signal DF. The dynamic focus signal DF passing through the capacitor C1 is supplied to the luminance correction signal generator 31, and the luminance correction signal generator 31 uses two resistors R1 and R2 and the variable resistor VR1. By adjusting the peak-to-peak value of the dynamic focus signal DF to an appropriate size, a basic luminance correction signal for luminance correction is made. The luminance correction signal output from the luminance correction signal generator 31 is supplied to one input terminal of the luminance signal synthesis unit 33, and the luminance signal of the entire screen is input to the other input terminal of the luminance signal synthesis unit 33. The two resistors R3 and R4 of the luminance signal synthesizing unit 33 play a role of synthesizing the luminance correction signal and the overall luminance signal applied to each resistor. The signal synthesized by the two resistors R3 and R4 is input to the inverting terminal (-) of the amplifier AMP. The resistors R7 and R8 and the capacitor C2 coupled between the inverting terminal (-) of the amplifier AMP and the output terminal adjust the gain of the amplifier AMP. The luminance signal synthesized by the luminance signal synthesizing unit 33 is input to the luminance signal amplifying unit 34. The reference luminance signal adjusting unit 32 is a means for basically providing an average luminance size of the entire screen. The reference luminance signal adjusting unit 32 distributes the power supply Vcc to the variable resistor VR2 to synthesize the luminance signal through the two resistors R5 and R6. The non-inverting terminal (+) of the amplifier AMP of the unit 33 is input. The magnitude of the voltage applied from the reference luminance signal adjusting unit 32 to the non-inverting terminal (+) of the amplifier AMP of the luminance signal synthesizing unit 33 is adjusted by the variable resistor VR2 of the reference luminance signal adjusting unit 32. The basic output level of the amplifier AMP is determined by adjusting the reference luminance signal to adjust the voltage difference between the non-inverting terminal (+) and the inverting terminal (-) of the amplifier AMP. The luminance signal amplifier 34 amplifies the luminance signal supplied from the luminance signal synthesis unit 33 to a predetermined size using the transistor Q1 and the resistors R10 and R11. The luminance signal output from the luminance signal amplifier 34 is supplied to the image signal output unit 37 via the luminance signal output unit 35. The luminance signal output unit 35 includes a transistor Q2 and resistors R12 and R13 and serves as a buffer for the input signal. The image signal output unit 37 synthesizes the luminance signal supplied from the luminance signal output unit 35 and the image signal Sv supplied from the image signal amplifier 36. The video signal output from the video signal amplifier 36 removes the DC component while passing through the capacitor C3. The synthesized signal from the video signal output unit 37 is supplied to the cathode ray tube 38, and the output signal of the video signal output unit 37 is shown in FIG. FIG. 5 (a) shows the horizontal drive section of the signal input to the cathode ray tube 38, and FIG. 5 (b) shows the vertical drive section.

As described above, the television luminance correction device according to the present invention adaptively corrects the magnitude of the luminance signal of the entire screen according to the luminance characteristics of the cathode ray tube using the dynamic focus signal DF, thereby making it possible to display a high resolution screen or a large size. In screens, especially large screens such as projection screens, luminance correction for the entire screen is more effective.

Claims (8)

A luminance compensator for correcting a magnitude of a luminance signal such that the magnitude of the luminance signal is uniform throughout the screen in an apparatus for displaying a composite image signal, comprising: an input terminal to which a dynamic focus signal is input; A luminance correction signal generator for generating a luminance correction signal for correcting a luminance component by adjusting a magnitude of a dynamic focus signal input through the input terminal; A reference luminance signal adjusting unit for adjusting and generating a reference luminance signal corresponding to a basic level of the magnitude of the luminance signal of the entire screen; The luminance correction signal output from the luminance correction signal generation unit, the reference luminance signal output from the reference luminance signal adjusting unit, and the luminance signal included in the composite image signal are supplied to the luminance correction signal and the luminance signal as the reference. A luminance signal synthesizing unit for synthesizing the signal into a signal having a predetermined level by the luminance signal; And an image signal output unit configured to synthesize the luminance signal synthesized by the luminance signal synthesis unit and the image signal to supply the luminance compensated image signal to the display unit. The luminance correction apparatus of claim 1, further comprising a capacitor coupled between the input terminal and the luminance correction signal generator to remove a DC component from the dynamic focus signal. The brightness compensating device of claim 1, wherein the brightness compensating signal generator comprises a variable resistor for varying the magnitude of the dynamic focus signal. The display device of claim 1, wherein the luminance signal synthesis unit comprises: a resistor to which an output signal of the luminance correction signal generation unit is applied to one side terminal; Another resistor to which a luminance signal included in the composite video signal is applied to one terminal; And an amplifying unit connected with the other terminals of the two resistors, the connecting terminal being coupled to one input terminal, and the output signal of the reference luminance signal adjusting unit being applied to the other input terminal. . The brightness compensating apparatus of claim 4, wherein the brightness signal synthesizing unit further comprises a gain adjusting unit coupled between one input terminal and the output terminal of the amplifier and configured to adjust the gain of the amplifier. The apparatus of claim 1 or 4, wherein the reference luminance signal adjusting unit receives a DC voltage having a predetermined magnitude and adjusts a variable resistor for varying the level of the reference luminance signal supplied to one input terminal of the amplifier unit of the luminance signal synthesis unit. Luminance correction apparatus comprising a. The luminance signal amplifier of claim 1, wherein the luminance signal amplification unit is coupled between the luminance signal synthesis unit and the image signal output unit to amplify the luminance signal output from the luminance signal synthesis unit to a predetermined displayable size and supply the amplified luminance signal to the image signal output unit. Luminance correction device, characterized in that it further comprises. The luminance correction device of claim 1 or 8, wherein the image signal output unit comprises a capacitor for removing a DC component from an input image signal.