JPH07210109A - Method of driving flat display device - Google Patents

Abstract

PURPOSE:To prevent erroneous light emission and the change in light emission luminance based on deformation and distortion of a glass plate due to heat. CONSTITUTION:The luminance data by one frame constituting one picture are divided corresponding to division blocks of a discharge panel 11 so as to divide the whole discharge panel 11 to optional blocks, and whether or not a luminance signal level exceeds a prescribed level is discriminated at every block by a level detection means 32, and the conditions of peripheral blocks of the block becoming the prescribed level or above are discriminated, and the block causing a white peak is detected. This method is constituted so that the number of times where the white peak occurs continuously are integrated at every block by a block classification integration counter 34, and the fact that the number of times (times) exceeds a prescribed value is detected by a controller 30, and a control signal lowering the luminance signal level of the block is outputted. Thus, since the luminance of a part where the number of occurrence times (times) of the white peak exceeds the prescribed value is lowered, the erroneous light emission and the change in the light emission luminance due to the deformation and the distortion of the glass plate are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving a flat display device such as a plasma display panel.

[0002]

2. Description of the Related Art In a general display device, power consumption increases when a white peak occurs on the entire screen.
The current value to the display device and the integrated value (= average value) of the input video signal are detected, and the brightness is controlled by adjusting the contrast, brightness, etc. accordingly, and the white peak is suppressed to reduce the power consumption. I am trying to let you.

However, in a flat panel display device such as a plasma display panel, as shown in FIG. 1, when a spot-like white peak is continuously generated instead of the entire screen, the glass surface is partially heated. The heat causes the glass plate to be deformed or distorted, resulting in erroneous light emission or a change in emission brightness.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and it is possible to simultaneously achieve reduction in power consumption and erroneous light emission or change in light emission luminance due to deformation and distortion of a glass plate. It is an object of the present invention to provide a method for driving a flat display device capable of achieving the above.

[0005]

In order to achieve the above object, a method of driving a flat panel display device according to the present invention has a luminance signal level of an input video signal corresponding to a part of a display screen with respect to a peripheral part of the part. It is characterized in that it detects that a high state has continuously occurred for a predetermined time, and accordingly lowers the level of the luminance signal corresponding to that portion relatively.

[0006]

In the method for driving a flat display device of the present invention, spot white peaks are detected and alleviated, so that the power consumption is reduced and the display panel is partially deformed or deformed by heat. It is possible to suppress the occurrence of erroneous light emission and prevent erroneous light emission and change in light emission luminance.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows a driving circuit according to an embodiment when the present invention is applied to a plasma display panel.

As shown in the figure, in the signal processing unit 1, the input composite video signal is, for example, 8 in the A / D converter 3.
It is converted into bit pixel data and sent to the frame memory 8 via the brightness adjusting means 31. On the other hand, the timing generation circuit 6 generates various timing pulses based on the horizontal and vertical sync signals extracted from the input composite video signal by the sync separation circuit 5.

The memory control circuit 7 outputs a write pulse synchronized with the timing pulse from the timing pulse generation circuit 6 and a read pulse synchronized with the read timing pulse generated by the read timing pulse generation circuit 20 based on this timing pulse to the frame memory. 8 is supplied to the frame memory 8, the frame memory 8 supplies the brightness adjusting means 31 based on the write pulse.
The pixel data from the image data is taken in and the image data taken in based on the read pulse is sent to the output processing circuit 9.

The output processing circuit 9 outputs only the most significant bit of each pixel data in synchronization with the timing pulse from the read timing pulse generating circuit 20 in the first mode,
A second mode in which only the (most significant-1) digit bit is sent,
.. The pixel data transmission mode of the eighth mode in which only the least significant bit is transmitted is transmitted to the address electrode driver 13 for each field.

The write / erase control circuit 10 outputs a drive signal for writing or erasing in synchronization with the timing pulse from the read timing pulse generating circuit 20 to the sustain electrode driver 12 of the discharge panel 1 of the display section 2. Supply to.

From the address electrode driver 13 to the column electrode X1
Data pulses having a positive characteristic are applied to .about.Xm, and negative sustain pulses are applied from the sustain electrode driver 12 to the row electrodes Y1 to Ym. It should be noted that each sustain pulse is provided with a scan pulse having a negative characteristic for starting light emission in response to the data pulse and an erase pulse having a short negative pulse width for stopping the light emission.

The pixel at the intersection of each row electrode and column electrode starts light emission by application of a data pulse and a scan pulse, discharge light emission is repeatedly performed by a sustain pulse, and light emission is stopped by an erase pulse.

As described above, the A / D converter 3 converts the composite video signal into 8-bit image data according to the sampling clock supplied from the timing pulse generation circuit 6. The block-by-block level detection means 32 determines whether or not the brightness data exceeds a predetermined level for each block obtained by dividing an arbitrary number of brightness data for one frame constituting one screen, and the peripheral block status determination means 33. Is
The situation of the peripheral blocks with respect to the blocks exceeding the predetermined level is determined, and the spot-like white peak is detected.

In this way, the number of white peak occurrences (time) detected by the level detection means 32 and the peripheral block status determination means 33 is the block-by-block integration counter 34.
Is added up for each block.

When the number of white peak occurrences (time) for any block exceeds a predetermined value (for example, several tens of seconds to several minutes), the controller 30 determines that the number of white peak occurrences (time) is a predetermined value. The control signal for the block exceeding the above is output.

When the brightness adjusting means 31 receives the control signal from the controller 30, the brightness adjusting means 31 adjusts the contrast, brightness, etc. by correcting the serial data of the Y / C signal included in the composite video signal. .

In this way, when a part of the display screen is extremely bright and the surroundings are dark for a long time (for example, several tens of seconds to several minutes), the display panel becomes hot. Can be prevented.

In the above, an example in which it is applied to a plasma display panel has been shown, but it goes without saying that the present invention can also be applied to other flat display devices such as EL display devices and liquid crystal display devices.

[0020]

As described above, according to the driving method of the flat display device of the present invention, the luminance signal level of the input video signal corresponding to a part of the display screen is higher than the peripheral part of the part. Since it is detected that it has occurred continuously for a predetermined time and the brightness of that part is lowered accordingly, the occurrence of partial heat deformation and distortion on the glass plate is suppressed, It is possible to prevent erroneous light emission and change in light emission luminance due to deformation and distortion.

[Brief description of drawings]

FIG. 1 is a diagram showing a white peak occurrence state in the discharge panel of FIG.

FIG. 2 is a diagram showing a driving circuit according to an embodiment of a driving method of a flat panel display device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal processing section 2 Display section 11 Discharge panel 30 Controller 31 Brightness adjusting means 32 Level detection means for each block 33 Peripheral block status determination means 34 Integration counter for each block

Claims (1)

[Claims] 1. A method of detecting that a state in which a luminance signal level of an input video signal corresponding to a part of a display screen is high with respect to a peripheral part of the part continuously for a predetermined time, and correspondingly corresponding to the part is detected. Driving method of a flat panel display device, wherein the level of a luminance signal to be controlled is relatively lowered.