KR20040026413A - Image displayer with rejection after image - Google Patents

Abstract

PURPOSE: An image display system having an image sticking removing function is provided to reduce deterioration of pixels and remove image sticking. CONSTITUTION: An image display system includes a receiver(110), a signal processor(200), and a controller(300). The receiver receives a broadcasting signal and tunes a predetermined channel. The signal processor processes the broadcasting signal and outputs a video signal to be displayed on a screen. The controller changes an image displayed on the screen when video signals having the same pattern, output from the signal processor, are displayed on the screen for a period of time longer than a predetermined period of time.

Description

Image display device with afterimage removal function {Image displayer with rejection after image}

The present invention relates to a video display device, and more particularly, to a video display device having an afterimage removal function.

In general, a display device (eg, a CRT, LCD, PDP, etc.) for displaying an image has a feature of deteriorating pixels when displaying a still image for a long time. For example, when a stock display is viewed with a video display device, a fixed character and a graph are concentrated on a specific pixel of the video display device for a long time, so that a certain pixel may shorten its lifespan compared to other pixels in the vicinity. In particular, in the case of the PDP representing an image by ultraviolet rays generated during gas discharge, the degradation of pixels is more serious. PDP generates light by applying an electric field to a tube in which helium and xenon gas are embedded. The PDP is discharged by a residual electric field for a predetermined time even when the supply of the electric field is stopped. Accordingly, when watching a program such as a stock quote on the PDP, when a specific pixel keeps emitting light by a fixed character and a graph, the pixel becomes brighter than necessary, and when switching to another image by the residual electric field of the pixel, Afterimage phenomenon occurs.

1 is a view illustrating a conventional screen protection method.

As shown in the related art, when a still image is displayed on the screen for a predetermined time or more, in order to reduce the occurrence of an afterimage of the still image, each pixel constituting the screen is shifted left and right by four pixels / line at a predetermined time. . For example, when an image displayed on an image display device (not shown) is a still image, every pixel of 10 seconds or more is moved to the right, the lower side, the right side, and the lower side by four pixels and four lines. 8 pixels / line each. As a result, the display device returns to its original position after one minute, and it is possible to protect the pixels to some extent even on a still image. However, in the pixel shifting method as shown in FIG. 1, the paths to be moved every 10 seconds are determined, and thus, the pixels having the predetermined moving paths cannot be deteriorated and the afterimage remains.

Meanwhile, in addition to the screen protection method described with reference to FIG. 1, a method of reducing the brightness of each pixel constituting the screen by 50% when a still picture exceeds a predetermined time has been presented. It did not block the afterimage phenomenon.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an image display device with less degradation of pixels and less afterimage phenomenon.

1 is a view for explaining a conventional screen protection method, and

Figure 2 shows a block diagram according to a preferred embodiment of the video display device having the afterimage removal function.

* Description of the symbols for the main parts of the drawings *

110: tuner 120: analog-to-digital converter

200: signal processing unit 210: signal separation unit

220: image signal processor 230: audio signal processor

300: control unit 310: comparison unit

320: character signal detection unit 330: counter

340: microcomputer 350: switching unit

410: PDP panel 420: speaker

430 power

According to the present invention, the object of the present invention includes a receiver for receiving a broadcast signal and tuning a predetermined channel, a signal processor for processing a broadcast signal tuned by the receiver, and outputting a video signal for display on a screen. When the signal is displayed on the screen for more than a predetermined time, it is achieved by the controller for changing the image displayed on the screen.

Preferably, the controller sequentially stores the video signal output from the signal processor every frame, and compares the sequentially stored frames and outputs a comparison result every predetermined time, the same frame as the comparison result of the comparison unit is continuous A counter for counting the number of times and a counter value of the counter are respectively compared with at least one preset value.When the count value of the microcomputer and the counter which changes the video signal according to the comparison result exceeds the preset final setting value, the power is applied from the outside. It includes a switching unit for turning off.

Preferably, the microcomputer outputs a first control signal to the signal processor to reduce the signal level of the video signal output to the screen by a predetermined amount when the count value of the counter exceeds a first preset value. When the second preset value is exceeded, the receiver outputs a second control signal for changing the channel selected by the receiver to the receiver, and when the count value exceeds the third preset value, the screen is controlled to configure the screen. Outputs a third control signal for flickering pixels in contrasting colors to the screen, and outputs the fourth control signal for turning on / off power applied from the outside when the count value exceeds the preset fourth set value. .

Preferably, a text signal detection unit is provided between the output terminal of the signal processing unit and the counter, and when the same text signal is displayed on the screen for more than a predetermined time in the signal processing unit, the text signal detection unit outputs a predetermined pulse to the counter every predetermined time. Include.

Preferably, the text signal is any one of a caption broadcasting subtitle signal, a teletext signal, and a teleweb signal.

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

Figure 2 shows a block diagram according to a preferred embodiment of the video display device having the afterimage removal function.

The video display device having the afterimage removal function shown in the drawing includes a tuner 110, an analog-to-digital converter (A / D converter) 120, a signal processor 200, a controller 300, a PDP panel 410, and a speaker ( 420, and a power source 430.

The tuner 110 tunes any one of a broadcast signal transmitted from a broadcast station or a satellite, and the analog-to-digital converter 120 converts the tuned broadcast signal to analog-digital conversion.

The signal processor 200 separates the analog-digital converted broadcast signal into an audio signal and a video signal, processes it, and outputs the processed signal to the PDP panel 410 and the speaker 420.

The controller 300 determines whether the image signal processed by the signal processor 200 is a still image or a moving image. As a result of the determination, when the same video signal is displayed on the screen for more than a preset time, the tuner 110 is controlled so that the tuner 110 tunes to another broadcast signal or the signal level of the video signal applied to the PDP panel 410. Lower or cut off the video signal applied to the PDP panel 410, and finally cut off the power 430 applied to the video display device.

Preferably, the signal processor 200 includes a signal separator 210, an image signal processor 220, and an audio signal processor 230.

The signal separator 210 separates the broadcast signal output from the analog-digital converter 120 into a video signal and an audio signal.

The video signal processor 220 and the audio signal processor 230 process the video signal and the audio signal, respectively, and output the same to the PDP panel 410 and the speaker 420.

Preferably, the controller 300 includes a comparator 310, a text signal detector 320, a counter 330, a microcomputer 340, and a switching unit 350.

The comparator 310 sequentially stores the image signals output from the image signal processor 220 to the PDP panel 410 for each frame, and compares the sequentially stored frames. Accordingly, it is detected whether the PDP panel 410 continues to display the same image, that is, a still image, and if it is determined that the same screen is continuously displayed on the PDP panel 410, one pulse is output. The output interval of the pulse is made according to a preset time.

The text signal detector 320 detects an image displayed on the PDP panel 410 when a video or a text caption does not change. In general, when viewing a program that expresses stock quotes in graphs or letters, in addition to general dramas and news, the video display apparatus often does not change letters / numbers that express stock quotes. As a result, a specific pixel of the PDP panel 410 continuously maintains a light emitting state, thereby deteriorating a state of the pixel, and the deteriorated pixel generates an afterimage when a channel is changed. When the character signal detection unit 320 watches a program similar to the above, the character signal detection unit 320 detects whether or not the character signal located in a specific region of the PDP panel 410 is changed every predetermined time. Generate a pulse. Here, the text signal detection unit 320 detects a broadcasting caption subtitle signal, a teletext signal, a teleweb signal, and the like.

The counter 330 counts pulses output at predetermined times by the comparator 310 and the character signal detector 320. The coefficient of the pulse is reset when the moving picture is applied to the comparing unit 310 and when the text signal applied to the text signal detecting unit 320 is changed.

The microcomputer 340 controls the tuner 110, the image signal processor 220, the PDP panel 410, and the switching unit 350 based on the count value counted by the counter 330.

The microcomputer 340 has a predetermined memory (for example, RAM, ROM, etc.), and stores the first to fourth setting values therein and compares these setting values with the count values output from the counter 330. As a result of the comparison, when the count value of the counter 330 is larger than the first set value, the video signal processor 220 is controlled to reduce the signal level of the video signal output from the video signal processor 220 to the PDP panel 410. The luminance of an image displayed on the PDP panel 410 is reduced. As a result, the residual electric field excited by the PDP panel 410 is reduced, thereby reducing the afterimage phenomenon in the PDP panel 410. If the count value of the counter 330 is larger than the second set value, the microcomputer 340 controls the tuner 110 to tune another broadcast signal to switch the image displayed on the PDP panel 410, and the counter. If the count value is larger than the third set value, the microcomputer outputs a predetermined pattern to the PDP panel 410. Here, the preset pattern means that the colors (for example, white and black) contrasted with each other are displayed on each pixel of the PDP panel 410 for the protection of the PDP panel 410, thereby remaining in each pixel constituting the PDP panel 410. This means that no electric field is formed. As a result, afterimages do not occur in each pixel of the PDP panel 410. Finally, when the count value of the counter exceeds the fourth set value, the microcomputer 340 controls the switching unit 350 to cut off power applied to the video display device, thereby constituting the PDP panel 410. To protect the pixels.

That is, by controlling the PDP panel 410 sequentially according to the four preset values as described above, afterimages of pixels constituting the PDP panel 410 are sequentially reduced by sequentially decreasing the electric field applied to the PDP panel 410. Decreases. Conventionally, the method of moving the pixels constituting the PDP panel 410 or reducing the electric field applied to the pixels eventually deteriorates the pixels over time. However, the present invention is directed to configuring the PDP panel 410 according to a preset time. By sequentially protecting the pixels, the degradation of the pixels as well as the prevention of deterioration of the pixels are reduced.

As described above, by sequentially protecting the pixels constituting the PDP panel according to a preset time according to a preset setting value, the present invention prevents deterioration of the pixels constituting the PDP panel and reduces the occurrence of afterimages in the pixels.

Claims (5)

A receiver which receives a broadcast signal and tunes into a predetermined channel; A signal processor for processing a broadcast signal selected by the receiver and outputting a video signal to be displayed on a screen; And And a control unit for changing the image displayed on the screen when the image signal having the same pattern from the signal processor is displayed on the screen for more than a predetermined time period. . The method of claim 1, The control unit, A comparison unit sequentially storing the video signal output from the signal processing unit every frame, and comparing the sequentially stored frames and outputting a comparison result every predetermined time; A counter for counting the number of times the same frame is continuous as a result of the comparison of the comparison unit; A microcomputer that compares the count value of the counter with at least one preset value and changes the video signal according to a comparison result; And And a switching unit to turn on / off power applied from the outside when the count value of the counter exceeds a predetermined final set value. 2. The method of claim 2, The microcomputer, When the count value of the counter exceeds a predetermined first set value, a first control signal for reducing a signal level of the video signal output to the screen by a predetermined amount is output to the signal processor, and the count value is pre-set. When the second set value is exceeded, the second control signal for changing the channel tuned by the receiver is output to the receiver, and when the count value exceeds the preset third set value, the screen is controlled to display the screen. Outputting a third control signal for blinking each pixel constituting each of the pixels to be contrasted with each other on the screen, and when the count value exceeds a fourth preset value, the power for turning on / off the power applied from the outside And a fourth image control device for outputting a fourth control signal. The method of claim 2, It is provided between the output terminal of the signal processing unit and the counter, When the same text signal is displayed on the screen for more than a predetermined time in the signal processor, a text signal detector for outputting a predetermined pulse to the counter every predetermined time; afterimage removal function characterized in that it further comprises Image display device having a. The method of claim 3, The text signal is, An image display device having an afterimage removing function, which is any one of a caption broadcasting subtitle signal, a teletext signal, and a teleweb signal.