KR100813715B1 - Method for minimizing image sticking effect of a plasma display panel - Google Patents

Abstract

The present invention relates to a method of removing afterimages such that afterimages do not occur even when a still image persists in a PDP. The afterimage removing method of the present invention includes detecting that an input image signal is a still image, setting the image retention mode to a "afterimage removal mode" when the still image lasts for a predetermined time, and in the afterimage removal mode, a predetermined number of lines in one frame. Displays a normal video signal, displays the remaining lines of a white or black video signal, and cancels the afterimage removal mode if the input video signal is a video signal.

According to the present invention, it is possible to prevent afterimages from occurring more efficiently without affecting the image quality.

PDP, Afterimage, Image Sticking

Description

Afterimage removal method in plasma display panel {METHOD FOR MINIMIZING IMAGE STICKING EFFECT OF A PLASMA DISPLAY PANEL}

1 is a block diagram generally showing a PDP display device according to the present invention;

2 is a block diagram illustrating a PDP display device for detecting input of a still image according to an embodiment of the present invention.

Figure 3 is a flow chart for sequentially explaining the process of setting the "image retention mode" according to the present invention.

Figure 4 is a flow chart for sequentially explaining an embodiment of the afterimage removal method according to the present invention.

5 is a flowchart for sequentially explaining another embodiment of the afterimage removing method according to the present invention;

6 is a screen for setting the afterimage removal mode according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: video processor

110: analog-to-digital converter (ADC)

130: PDP module

132: drive unit                 

140: micom

250: still image detection unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing an image sticking phenomenon that occurs when a still image continues for a long time in a plasma display panel (hereinafter referred to as "PDP").

PDP is a display that displays characters or graphics by using light generated by excitation of phosphors by 147 nm ultraviolet rays generated during the discharge of He + Xe or Ne + Xe gas. With this development, image quality has been greatly improved and manufacturing cost has been reduced, attracting attention as a next generation display.

However, such a PDP is used as a PC monitor or a TV, and when it is used as a PC monitor, the same screen is often displayed for a long time, and even when used as a home TV, it is the same as a broadcast control screen. Displaying the screen for a long time often occurs.

However, unlike CRTs and LCDs, in case of a still image being displayed for a long time, the PDP wears out phosphors in a cell partition wall and causes an afterimage between a bright part and a dark part. There is a problem that is reduced significantly.

As described above, the conventional PDP products have proposed various methods to reduce the afterimage phenomenon that occurs when a still image continues for a long time.

One way is to reduce afterimages by gradually dimming the overall brightness of the image. However, the method of reducing the brightness of the image as a whole does not significantly affect the afterimage prevention, because only the difference is reduced because the still image keeps its position.

Another method is to move the still picture up, down, left, or right after a certain time so that the effect on the cell is not concentrated. By the way, the motion of the screen is not large, but there is a problem that the viewer to recognize the movement.

Another method is to reduce the brightness (maximum brightness) to 30% when the same screen lasts more than 5 minutes, and automatically adjust the brightness of the microcomputer to return to normal brightness when the data on the same screen changes by 0.36%. To have it. However, this method is effective for removing afterimages when the same screen is displayed for less than 5 hours, but there is still a problem that afterimages occur when the same screen is maintained for 5 hours or more.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus in which a afterimage does not occur even if the same image is displayed for a predetermined time in a PDP panel.

A feature of the afterimage removal method in the plasma display panel according to the present invention for achieving the above object is in the afterimage removal method in the plasma display panel (PDP), (a) detecting the duration of the still image on the PDP; And (b) when the detected duration is greater than or equal to a predetermined time, the operation mode of the PDP is set to an afterimage elimination mode, and a predetermined number of lines for one frame display a normal video signal and The remaining lines include displaying a video signal of black or white, and (c) canceling the afterimage removing mode and sequentially displaying the input video signal when a video is input while displaying a still image. Characterized in that.

In this case, in the afterimage removal mode, the ratio of the number of lines displaying a normal video signal to the number of lines displaying a black or white video signal is preferably determined according to the duration of the still image.

On the other hand, it is preferable that the line displaying the black or white video signal in the previous frame displays the normal video signal in the subsequent frame.

Another feature of the afterimage removal method of the present invention for achieving the above object is (a) setting a frame frequency that the user will not display in the afterimage removal mode, (b) the image signal input to the plasma display panel Determining whether the still image or the moving image is a still image, (c) if the input image signal is a still image, detecting a time for which the still image persists, and if the still image lasts for a predetermined time, the microcomputer sets an afterimage removing mode. Displaying a video signal of full white or full black without displaying a normal video signal for the number of frames corresponding to the predetermined frame frequency for a predetermined time interval; and (d) if the input video signal is a video. Canceling the afterimage removal mode and displaying the input image signal normally.

According to the present invention, an afterimage does not occur even if a still image persists in the plasma display panel.

Hereinafter, a PDP display device capable of preventing efficient afterimage generation and an afterimage removal method thereof will be described in detail with reference to the accompanying drawings.

An embodiment of the afterimage removing method according to the present invention includes the steps of: (a) determining whether an input image is a still image or a video; (C) releasing the " afterimage removal mode " if the inputted image is a video; and (d) under the afterimage removal mode, one line for a certain number of lines in one frame. Displaying a white or black video signal. Hereinafter, each step will be described in detail.

First, the step of determining whether the input image of step (a) is a still image or a moving image will be described with reference to FIG. 1.

1 is a block diagram schematically illustrating a configuration of an image display apparatus having a general PDP module. As shown in FIG. 1, in general, an image display apparatus including a PDP module receives an image signal to be displayed through an video processor 100 from an external form in an analog form. The input image signal is converted into a digital image signal through the ADC 110, and then converted into a format suitable for the PDP module by the scaler 120 and input to the PDP module 130 for display. On the other hand, the overall operation is controlled by the microcomputer 140.

In such a PDP display device, whether the input video signal is a moving picture or a still picture is determined by the driving unit 132 in the PDP module. The detection signal indicating whether the input video signal is a moving picture or a still picture is transmitted to the microcomputer 140. When the microcomputer receives the detection signal indicating that the still image is received from the PDP module, the microcomputer checks the time duration of the still image using a time counter, and sets the "afterimage removal mode" when the still image lasts for a predetermined time. On the other hand, when the microcomputer receives a detection signal indicating that the video input from the PDP module is a video, it releases the "afterimage removal mode" and controls to display normally.

Meanwhile, in the present invention, determining whether the input image is a moving image or a still image may be performed in another form as illustrated in FIGS. 2 and 3.

Referring to FIGS. 2 and 3, a still picture detecting unit 250 is further provided between the ADC 110 and the scaler 120, and the still picture detecting unit 250 continuously operates from the ADC 110. If the two frames to be output are the same (step 300), a detection signal indicating this is transmitted to the micom (step 310). When the microcomputer receives a detection signal indicating that two consecutive frames are the same, the microcomputer checks the duration of the same image using an internal time counter (step 320). Next, when the time for which the same image is maintained reaches more than a predetermined time, the microcomputer sets the "afterimage removal mode" (step 330). On the other hand, if the detection signal indicating that two consecutive frames are the same from the still image detection unit 250 is not received, the microcomputer releases the "afterimage removal mode".

As described above, when the "afterimage removal mode" is set by the micom, a certain number of lines in one frame display a normal video signal, and the following lines display a white or black video signal, To prevent this from happening. In addition, as the duration of the still image increases, the afterimage prevention effect may be further increased by adjusting the number of lines for displaying a normal image signal. In addition, the line on which the white or black video signal is displayed in the current frame is displayed so that the normal video signal is displayed in the subsequent frame, thereby preventing the afterimage while preventing the viewer from detecting a change in the image.

Hereinafter, the above-described display method will be described by way of example with reference to the following Table 1 and FIG. 4.

Still image duration First frame Second frame Third frame Fourth frame Fifth frame Still image start Main screen display 5 minutes 1,5,9,13 ... the first line is a black display 2,6,10,14 ... th line is black display 3,7,11,15 ... th line is black display 4th, 8th, 12th, 16 ... th line is black display Repeat first frame. 7 minutes 1,4,7,10 ... th line is black display 2,5,8,11 ... th line is black display 3,6,9,12 ... th line is black display Repeat first frame. Repeat second frame. 10 minutes 1,3,5,7 ... th line is black display 2,4,6,8..th line is black display Repeat first frame. Repeat second frame. Repeat first frame.

First, when a still image starts, all frames display a normal image signal (step 410).

Next, when 5 minutes of the duration of the still image has elapsed (step 420), one line of four lines in one frame displays a black image signal (step 430). As shown in Table 1, the first frame includes 1, 5, 9, 13... The first line displays a black video signal, and the remaining line displays a normal video signal. The second frame is a line in which a black video signal is displayed in the first frame, so that the second frame is 2, 6, 10, 14... The first line displays a black video signal, and the remaining line displays a normal video signal. The third and fourth frames are also displayed in this manner, and the fifth frame is repeatedly displayed in the same manner as the first frame.

On the other hand, when the duration of the still image is 7 minutes or more (step 440), one line of the three lines in one frame displays the black image signal (step 450). As shown in Table 1, the first frame includes 1,4,7,10... The first line displays a black video signal, and the remaining line displays a normal video signal. The second frame is a line in which the black video signal is displayed in the first frame, so that the second frame is 2, 5, 8, 11... The first line displays a black video signal, and the remaining line displays a normal video signal. The third frame is also displayed in this manner, and the fourth frame is repeatedly displayed in the same manner as the first frame.

 On the other hand, when the duration of the still image is 10 minutes or more (step 460), one line of the two lines in one frame displays a black image signal (step 470). As shown in Table 1, the first frame includes 1, 3, 5, 7... The first line displays a black video signal, and the remaining line displays a normal video signal. The second frame is a line in which a black video signal is displayed in the first frame, so that the second frame is 2, 4, 6, 8... The first line displays a black video signal, and the remaining line displays a normal video signal. The third frame is repeatedly displayed in the same manner as the first frame.

Hereinafter, another embodiment of the present invention will be described with reference to FIGS. 5 and 6.

In the present embodiment, as shown in FIG. 6, when the still image persists for a predetermined time in the afterimage removal mode through the input menu screen where the user can set the frame frequency in the afterimage removal mode (ISM Mode). The frame frequency for displaying a full white or full black image for a predetermined time interval, for example, 1 second, is input. At this time, the frame frequency number of the afterimage removal mode is set to "0" as a default, and it is preferable to set the desired frame frequency. Therefore, unless the user inputs it separately, the frame frequency in the afterimage removal mode is set to "0", thereby operating normally even in the afterimage removal mode.

Next, if the image input to the image display apparatus is a still image and the still image persists for a predetermined time or more, the microcomputer in the image display apparatus sets the afterimage removal mode and reads the preset frame frequency (step 520). During the predetermined time interval, a full white or full black screen is displayed by the read frame frequency (step 550).

That is, assuming that m frames are displayed for 1 second, and the user sets n afterimage removal mode to n, the number of full white images to be displayed for 1 second is n. Is displayed at m ÷ n frame intervals. For example, if m is set to 60 and n is set to 2, one frame displays a full white image every 30 frames.

On the other hand, if it is detected that a video is input to the image display device, the micom cancels the afterimage removal mode and displays the input image signal normally.

According to the present invention, an afterimage does not occur in the PDP even if the same screen is continued for a predetermined time or more. As a result, the PDP can be effectively used as a monitor of a PC that has the same screen, and can be usefully used in a product advertisement screen where the still screen is continued.

Claims (5)

In the afterimage removal method in the plasma display panel (PDP), Detecting a time duration of a still image in the PDP; When the detected duration is more than a predetermined time, the operation mode of the PDP is set to an afterimage elimination mode, and a certain number of lines display a normal video signal for one frame, and the remaining lines are black or white. Displaying an image signal of the; If a video is input while displaying a still image, canceling the afterimage removing mode and sequentially displaying the input image signal. An afterimage removal method in a plasma display panel having a. The method of claim 1, wherein, in the afterimage removal mode, a ratio of the number of lines displaying a normal image signal to the number of lines displaying a black or white image signal is determined according to the duration of the still image. The afterimage removal method in the plasma display panel. The afterimage removal method of claim 1, wherein the line displaying the black or white video signal in the previous frame displays the normal video signal in the subsequent frame. In a PDP display device having a microcomputer, a converter, a scaler, and a PDP module, A still image detecting unit is further provided between the converter and the scaler. The still image detecting unit detects that two identical frames are continuously output from the converter, and transmits a detection signal indicating the same to the micom, The microcomputer checks the duration of the still image when the detection signal is transmitted from the still image detector, sets the afterimage removal mode when the still image lasts for a predetermined time, and detects the detection signal from the still image detector. If is not transmitted, cancel image retention mode and display input video signal normally. The scaler minimizes afterimage generation, in which a certain number of lines display a normal video signal for one frame and the remaining lines display a white or black video signal instead of a normal video signal in an afterimage removing mode. Video display device. (a) setting a frequency of frames not to be displayed by the user in the afterimage removal mode; (b) determining whether an image signal input to the plasma display panel is a still image or a moving image; (c) if the input image signal is a still image, detecting a time for which the still image lasts; if the still image lasts for a predetermined time or more, sets an afterimage removal mode, and sets the afterimage to the preset frame frequency for a predetermined time interval. A corresponding number of frames displaying a full white or full black video signal without displaying a normal video signal, and (d) if the input image signal is a moving image, canceling the afterimage removing mode and displaying the input image signal normally An afterimage prevention method for a plasma display panel having a.

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