JPH08248934A - Burning preventing circuit for display device - Google Patents

Abstract

PURPOSE: To make the burning of a display device inconspicuous by blurring the boundary between a lighting and a nonlighting while moving a display screen by the amount equivalent to a required number of pexels after the lapse of a required time. CONSTITUTION: The video signal from an input part 1 is converted into a digital signal in an A/D conversion part 2 and the required signal processing and synchronization control, etc., are performed in a signal processing and synchronization control part 3 to be inputted to the display part 4 to display it on a plasma display panel, etc. The signal from the A/D conversion part 2 is inputted to an APL detecting part 8 and the mean luminace level of the signal is detected to be recorded in a memory part 9. Then, the data are read out to be inputted to a discrimination part 10 via a control part 11 and next, the discrimination part 10 discriminates the presence of difference between the data concerned and data to be recorded in the memory part 9 by comparing them. When the difference is not present, a timer 6 starts to count a time based on a program read from a storage part 5 and after the lapse of a required time, the display position on the screen is moved horizontally and vertically by an amount equivalent to a required number of pixels by outputting a control signal to a display position control part 7 and by controlling the signal processing and synchronization control part via the display position control part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burn-in prevention circuit for a display, and to a display-shifted circuit in which the display position of the screen is slightly shifted so that the same portion is not illuminated for a long time to prevent burn-in.

[0002]

2. Description of the Related Art Plasma display panels (PDPs)
In such display devices, image sticking occurs on the screen due to the display like a cathode ray tube. This burn-in is lit with high brightness,
In addition, it appears prominently when the same screen is displayed for a long time. For example, as shown in FIG. 3A, when a screen with a high brightness portion 21 is displayed for a long time and then a white screen is displayed, As shown in (b), the shadow 22 remains as if it were burned in on the high-intensity part of the screen of (a). In order to prevent this image sticking, for example, when the same image is displayed for a long time, there is a method of inverting the image, reducing the brightness of the screen, or switching to another screen prepared in advance. Some of them automatically turn off the power when the state continues for a required time. However, the one that inverts the image is a different image from the appearance, and it is good if the original screen is bright when the screen brightness is lowered, but it is difficult to see because the image sinks when changing to a dark screen There is a problem that
It may be misunderstood that the device may be abnormal if the screen you were watching suddenly switches to another screen.

[0003]

Even if the display position of the screen being viewed is moved, if the amount of movement is small, it will not be noticed that the movement has occurred, or even if it is noticed, there should be little problem. In view of such a point, in the present invention, when the same screen is continuously displayed for a required time or more, the display position of the screen is slightly moved in the vertical direction or the horizontal direction, and the burn-in of the lighting / non-lighting boundary is conspicuous. It is to prevent it.

[0004]

In order to solve the above problems, the present invention converts a video signal into a digital signal and performs necessary signal processing and control of a display position for display. It is an object of the present invention to provide a burn-in prevention circuit for a display unit, which is provided with a storage unit for storing a program for moving the display position of the screen and moves the display position of the screen based on the program read from the storage unit.

[0005]

With the above-described configuration, in the image sticking prevention circuit of the present invention, the synchronization control section changes the display position of the screen by the video signal input to the display section every time a required time elapses. At the required time interval, the pixel is moved rightward or leftward and upward or downward by the required pixel, respectively, so that the burning is not noticeable at the lighting / non-lighting boundary. Alternatively, the display position is moved when the same screen is continuously displayed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the burn-in prevention circuit for a display according to the present invention will be described in detail below. FIG. 1 is a block diagram of an essential part of an embodiment of an image sticking prevention circuit for a display according to the present invention. In the figure, reference numeral 1 is an input unit for inputting a video signal. 2 is A /
The D converter converts the video signal from the input unit 1 into a digital signal. A signal processing / synchronization control unit 3 processes the signal from the A / D conversion unit 2 and controls synchronization. Four
Is a display unit, which uses a PDP or the like as a display and displays based on a signal from the signal processing / synchronization control unit 3. A storage unit 5 stores a program for moving the display position of the screen and the like. 6
Is a timer that starts timing when the power is turned on and outputs a signal each time the required time has elapsed. A display position control unit 7 controls the signal processing / synchronization control unit 3 based on the program read from the storage unit 5, and moves the position of the screen displayed on the display unit 4 by the required number of pixels. 8 is an APL detector,
The average luminance level of the video signals of all the pixels of one screen of the video signal from the / D converter 2 is detected. 9 is a memory unit, AP
Data from the L detector 8 is recorded at required time intervals. Ten
The discriminating unit reads out the data previously recorded in the memory unit 9, compares it with the data recorded in the memory unit 9 this time, and outputs a signal when there is no difference. A control unit 11 controls each unit.

Next, the operation of the image sticking prevention circuit of the display according to the present invention will be described. The video signal from the input unit 1 is input to the A / D conversion unit 2, converted into a digital signal, input to the signal processing / synchronization control unit 3, and subjected to gamma correction for displaying on a PDP or the like of the display unit 4. The display position of the screen is controlled based on the signal from the display position control unit 7 while performing signal processing, processing of the synchronization signal, and the like. That is, according to the program read from the storage unit 5 via the control unit 11, in response to a signal output from the timer 6 each time the required time elapses,
As shown in FIG. 2, required pixels are moved to the right and downward,
For example, the display position is moved by one pixel. Then, when the amount of movement reaches the required number of pixels, the movement is performed in the opposite direction (leftward and upward) similarly. The timer 6 outputs a signal at an appropriately set time such as 30 minutes to 2 hours.

The above is an example of moving the screen irrespective of the presence or absence of motion of the image. However, when the contents of the screen do not move, the image sticking is conspicuous. Therefore, the screen should be moved when there is no motion. You can also Therefore, for example, the APL detection unit 8 is provided to detect the average luminance level (APL) of the video signal, and when there is no change in the average luminance level, it is determined that the same screen is continuing. That is, A
The data from the PL detection unit 8 is recorded in the memory unit 9 for each field, and when the data of the next field is recorded, this data is simultaneously input to the determination unit 10 and compared with the previous data read from the memory unit 9. To determine the difference. When it is determined that there is no difference, the timer 6 is started via the control unit 11 to start time measurement, the determination unit 10 continues to monitor the average brightness level, and the determination unit 10 determines the difference until the required time elapses. When the given signal is not output, the display position of the screen is moved based on the program from the storage unit 5.

[0009]

As described above, according to the image sticking prevention circuit of the display device of the present invention, the display screen of the PDP slightly moves in the vertical direction and the horizontal direction each time the required time elapses. Even when the same screen is displayed continuously for a long time, it is possible to make the burn-in of the boundary between lighting and non-lighting inconspicuous. Further, the screen can be moved little by little so that the viewer does not notice that the screen has moved, such as one pixel at a time, so that the viewer does not feel uncomfortable.

[Brief description of drawings]

FIG. 1 is a block diagram of an essential part of an embodiment of an image sticking prevention circuit for a display according to the present invention.

FIG. 2 is a conceptual diagram for explaining screen movement.

FIG. 3 is a conceptual diagram for explaining burn-in of a display device.

[Explanation of symbols]

 2 A / D conversion unit 3 Signal processing / synchronization control unit 4 Display unit 5 Storage unit 6 Timer 7 Display position control unit (horizontal / vertical) 8 APL detection unit 9 Memory unit 10 Discrimination unit 11 Control unit

Claims (8)

[Claims] 1. A display unit for converting a video signal into a digital signal, performing necessary signal processing, controlling display position, etc. for display, and providing a storage unit for storing a program for moving a display position of a screen by the video signal, A burn-in prevention circuit for a display, which moves the display position of the screen based on the program read from the storage unit. 2. A first timer is provided which starts timing when the power is turned on and outputs a signal each time a required time elapses, and a signal from the first timer is used to display a screen based on a program read from the storage unit. The seizure prevention circuit for a display according to claim 1, wherein the display position is moved. 3. A for detecting an average luminance level of a video signal
The PL detection unit, the memory unit that stores the data from the APL detection unit at required time intervals, the data recorded in the memory unit is read, and compared with the data recorded next in the memory unit to determine whether there is a difference. 2. The seizure prevention circuit for a display device according to claim 1, further comprising a discriminating unit, wherein the display position of the screen is moved based on a program read from the storage unit in response to a signal from the discriminating unit. 4. A second timer that starts timing with a signal without a difference from the discriminating unit, continues the timing until a signal with a difference is output from the discriminating unit, and outputs a signal each time a required time elapses. 4. The seizure prevention circuit for a display according to claim 3, wherein the display position of the screen is moved based on a program read from the storage section by a signal from a second timer. 5. The program stored in the storage unit is
The display according to claim 1, claim 2, claim 3 or claim 4, wherein the display position of the screen is moved rightward or leftward and upward or downward by the required number of pixels. Anti-seizure circuit. 6. The program stored in the storage unit is
Move the display position of the screen to the right or left, and up or down by the required number of pixels,
5. The seizure prevention circuit for a display device according to claim 1, claim 2, claim 3, or claim 4, wherein after the required amount of movement is reached, the required number of pixels is moved in the opposite direction. 7. The program stored in the storage unit is
The image sticking according to claim 1, claim 2, claim 3 or claim 4, wherein the display position of the screen is moved rightward or leftward and upward or downward by one pixel each. Prevention circuit. 8. The program stored in the storage unit is
Moving the display position on the screen to the right or left and up or down by 1 pixel each, and after moving to the required amount of movement, moves 1 pixel by 1 pixel in the opposite direction. The seizure prevention circuit for a display according to claim 1, claim 2, claim 3 or claim 4, which comprises