JP3454292B2 - Display burn-in prevention circuit - Google Patents

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 panel (PDP)
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 reversing the image, lowering the screen brightness, 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 reverses the image is that the screen becomes a different image visually, 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 so that the burning of the lighting / non-lighting boundary is conspicuous. It is to prevent it.

In order to solve the above problems, the present invention, in a display device for converting a video signal into a digital signal, performing necessary signal processing and controlling the display position, and displaying, moves the display position of the screen by the video signal. Storage unit for storing the above program and AP for detecting the average luminance level of the video signal
Data from the L detection section and the APL detection section are separated by the required time interval.
And the data stored in the memory section
Read out and compare with the data stored next in the memory section
With a discriminating unit that discriminates the presence or absence of
It is an object of the present invention to provide a burn-in prevention circuit for a display, which moves a display position of a screen based on a program read from the storage unit by a signal .

[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. Duration , average brightness level of video signal
When there is no change in the bell, the pixels are moved rightward or leftward and upward or downward by the required number of pixels 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
The data from the L detection unit 8 stores in the required time intervals. Ten
The discriminating unit reads out the data previously stored in the memory unit 9, compares it with the data stored 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. signal processing, the processing of the synchronization signal
Done.

[0008] APL detecting unit 8 detects an average luminance level of movies image signal (APL), when there is no change in the average luminance level you determined that the same screen is continued. That is, the data from the APL 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 input to the determination unit 10 at the same time and the previous data read from the memory unit 9 is recorded. Compare and 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. If there the signal is not output, the display position control unit 7 performs control to move the display position of the screen based on the program from the storage unit 5. Figure 2 shows the movement of the display position on the screen .
As shown in, the required pixels to the right and downward, for example,
For example, the display position is moved by one pixel. And the amount of movement
Has reached the required number of pixels, this time in the reverse direction (to the left and
And upward).

[0009]

As described above, according to the image sticking prevention circuit of the display according to the present invention, when the display screen of the PDP does not change in the average luminance level of the video signal for the required time ,
Since it moves slightly in the vertical direction and the horizontal direction, even when the same screen is continuously displayed for a long time, it is possible to make the burning of the lighting / non-lighting boundary 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 converter 3 Signal processing / synchronization control unit 4 Display 5 memory 6 timer 7 Display position controller (horizontal / vertical) 8 APL detector 9 memory 10 Discriminator 11 Control part

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Claims (4)

(57) [Claims] 1. A video signal is converted into a digital signal, and necessary signal processing and display position control are performed for display.
In the display unit , a storage unit that stores a program for moving the display position of the screen according to the video signal and an average luminance level of the video signal.
APL detection unit that detects the bell and the data from the APL detection unit.
Memory unit that stores data at required time intervals
The stored data is read out and then stored in the memory section.
A judgment unit that compares the data and judges whether there is a difference is provided.
A burn-in prevention circuit for a display device, wherein the display position of the screen is moved based on a program read from the storage unit by a signal indicating no difference from another unit . 2. A starts counting by the signal without difference from the determination unit continues the counting until the signal has a difference from the determination unit is output, to output the signal each time the required time filter timer the <br/> chromatography provided, said at signal from the timer, burn-in prevention circuit indicator as to the claim 1, wherein moving the display position of the screen based on the read program from the storage unit. 3. The program stored in the storage unit is
3. The burn-in prevention circuit for a display device according to claim 1 , wherein the display position of the screen is moved rightward or leftward and upward or downward by the required number of pixels. 4. 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,
3. The method according to claim 1 , wherein after the required movement amount is reached, the movement is performed by the required number of pixels in the opposite direction to the previous direction.
Anti-seizure circuit of the indicated display.