JPH07210113A - Method for driving plasma display panel - Google Patents

Abstract

PURPOSE:To reduce power consumption while maintaining the number of gradations by reducing a frequency of light emission of a line in the upper end and/or the lower end of a picture of every sub-field than the line in the center of a screen. CONSTITUTION:The display of 256 gradation is performed by dividing one frame into eight sub-fields and selecting light emission in the sub-field for pixels on every scanning line. Then, a position (timing when an erasure pulse is applied) of erasure is controlled so that the frequency of light emission (light emission time) is reduced for the scanning line (row) of the center of the screen as approaching the upper end (1 row) or the lower end (K row) of the screen. That is, respective scanning lines in the vicinity of the center of the screen of respective sub-fields are written by the application of a data pulse and a scanning pulse, and discharge light emission is started, and the discharge light emission is repeated by a maintaining pulse by the frequency of light emission according to the weighting, and the light emission is stopped by the application of the erasure pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of driving a plasma display panel which achieves low power consumption while maintaining the number of gradations.

[0002]

2. Description of the Related Art In a plasma display panel, a pair of discharge electrodes (cathode and anode) are regularly arranged between two glass plates containing a rare gas mainly containing neon, and minute electrodes formed at the intersections of both electrodes. This is a display panel that utilizes a discharge light emission phenomenon (negative glow, positive column) that is generated by applying a voltage to various discharge cells.

Further, such a plasma display panel is roughly classified into a DC type and an AC type in terms of operation. Further, the display function and the driving method are classified into a refresh method, a memory method, a self-scan method, and the like.

When performing color display on such a plasma display panel, it becomes necessary to add a gradation display function.

As a method of performing such gradation display, for example, as shown in FIG. 1, one frame displaying one screen is divided into a plurality of subfields and the light emission time of each subfield is controlled. Has been.

FIG. 1 shows a case where a display of 2 ⁸ = 256 gradations is performed. One frame period is divided into eight subfields 1 to 8 and the weighting is heavy (light emission time By extending the time of the (long) subfield and distributing the long time, the number of times of light emission is increased, the ratio of the light emission time is increased, and gradation display with high brightness is enabled.

Here, the time lengths of the first to eighth subfields are set to a ratio of 6: 3: 2: 1: 1: 1: 1: 1, respectively. Further, the light emission period from the excitation pulse to the erase pulse in each subfield is T,
T / 2, T / 4, T / 8, T / 16, T / 32, T / 6
It is set to 4, T / 128.

[0008]

In this way, gradation display is performed, but in the color display plasma display panel, display light is obtained by exposing the phosphor to ultraviolet rays generated by plasma. Therefore, the luminous efficiency is reduced. If the power is increased to compensate for this, the life is shortened and the power consumption is increased.

Therefore, it is possible to reduce the power consumption by lowering the amplitude of the video signal in the peripheral portion of the screen by utilizing the fact that there is no visual problem even if the luminance in the peripheral portion of the screen is slightly lower than that in the central portion. Although it is conceivable, there was a problem that the number of gradations in the peripheral portion of the screen was reduced. That is, for example, 2
This is because if the amount of light in the peripheral portion of the screen of a panel displaying 56 gradations is set to 50%, that portion can display only 128 gradations.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a driving method of a plasma display panel capable of reducing power consumption while maintaining the number of gradations. .

[0011]

In order to achieve the above object, the present invention provides a method for driving a plasma display panel, wherein one frame is divided into a plurality of subfields and gradation display is performed by modulating the number of times of light emission. It is characterized in that the number of times of light emission of the line at the upper end and / or the lower end of the screen of the subfield is made smaller than that of the line at the center of the screen.

[0012]

In the driving method of the plasma display panel according to the present invention, the number of light emission of the line at the upper end and / or the lower end of the screen of each sub-field, which does not cause a visual problem even if the brightness is slightly lowered, is determined by the line at the center of the screen. By further reducing the number, it is possible to drive with low power consumption while maintaining the original number of gradations in a pseudo manner.

[0013]

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

As shown in the figure, the A / D converter 1 converts the input composite video signal into, for example, 8-bit pixel data and sends it to the frame memory 3. The timing pulse generation circuit 5 generates various timing pulses based on the horizontal and vertical synchronization signals extracted from the input composite video signal by the synchronization separation circuit 4.

When the memory control circuit 6 supplies the write and read pulses synchronized with the timing pulse from the timing pulse generation circuit 5 to the frame memory 3, the frame memory 3 outputs from the A / D converter 1 based on the write pulse. Of the pixel data, and the pixel data acquired based on the read pulse is sent to the output processing circuit 7.

The output processing circuit 7 sends only the most significant bit of each pixel data in synchronization with the timing pulse from the write / read pulse generating circuit 1, only the (most significant -1) digit bit. The second mode for transmitting the ..., The pixel data transmission mode of the eighth mode for transmitting only the least significant bit is transmitted to the address electrode driver 8 for each field.

The write / erase control circuit 9 outputs a drive signal for writing or erasing in synchronization with the timing pulse from the write / read pulse generating circuit 2 to the first sustain electrode driver 10 and the second sustain electrode. Output to the electrode driver 11.

FIG. 3 shows the above-mentioned address electrode driver 8,
First sustain electrode driver 10 and second sustain electrode driver 1
1 shows a voltage waveform applied from 1 to each electrode.
That is, FIG. 3A shows the data pulse applied from the address electrode driver 8 to the column electrodes A1 to AJ. In the same figure, (b) shows the second sustain electrode driver 11 to the common row electrode Y.
3 shows a negative sustain pulse applied to 1 to YK.

The figures (c), (d) and (e) show the first,
From the second and third sustain electrode drivers 10 to the scan electrodes X1,
A sustain pulse having a negative polarity applied to X2 and X3 is shown. Here, to each sustain pulse, a scanning pulse for starting light emission and an erasing pulse with a short pulse width for stopping the light emission according to the data pulse are given.

FIG. 1F shows the row electrodes X1 and Y1 of the first row.
Is a signal waveform showing the discharge light emission state of the pixel at the intersection of the column electrodes A1 to AJ. The light emission is started by the application of the data pulse and the scan pulse, the discharge light emission is repeatedly performed by the sustain pulse, and the light emission is performed by the erase pulse. Indicates that it will be stopped.

FIG. 4 shows a driving method of the plasma display according to the present invention. In FIG. 4, 2 ⁸ = 25
The case where 6 gradations are displayed is shown, and one frame for displaying one screen is divided into eight subfields from first to eighth. The pixels on each scanning line can display 256 gradations by selecting light emission in each subfield. Then, in each subfield, the number of times of light emission (in other words, light emission time) with respect to the scanning line (row) at the center of the screen decreases as it approaches the upper end (1 line) or the lower end (k line) of the screen. The position (timing at which the erase pulse is applied) is controlled.

That is, each scan line in the vicinity of the screen center of each subfield is written by application of a data pulse and a scan pulse, discharge discharge is started, and the number of times of light emission according to the weighting (for example, the most weighted one is heavy). 128x4 times, 64x4 times, 32x in order from subfield
4 times, 16x4 times, 8x4 times, 4x4 times, 2x4 times, 1
The discharge pulse is repeatedly emitted by the sustain pulse and the emission pulse is stopped by the application of the erase pulse, and the number of emission of the scanning line in each subfield decreases as the upper end or the lower end of the screen is approached. , In the top (first row) or bottom (kth) line of the screen of each subfield, for example, 128 × 2 times, 64 × 2 times in order from the subfield with the highest weight,
32 × 2 times, 16 × 2 times, 8 × 2 times, 4 × 2 times, 2 × 2
The application timing of the erase pulse is controlled according to the scanning line (row) so that the number of times is 1 × 2 times.

FIG. 4 shows a structure in which the number of times of light emission of each scanning line in each subfield is gradually reduced from the scanning line at the center of the screen to the scanning line at the upper end or the lower end. May be done.

Further, the application of the above-mentioned erase pulse is performed by writing / writing.
In the erasing control circuit 9, it is performed at a timing corresponding to a scanning line (row).

Although the above embodiment shows the case of 256 gradation display, the present invention can be applied even if the gradation to be displayed is a value other than 256.

[0026]

As described above, according to the driving method of the plasma display panel of the present invention, the upper end and / or the lower end of the screen of each subfield which does not cause a visual problem even if the brightness is slightly lowered. By reducing the number of times of light emission of the line in the line from the line in the center of the screen, it is possible to drive with low power consumption while maintaining the original number of gradations in a pseudo manner.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a driving method for performing gradation display in a conventional plasma display panel.

FIG. 2 is a diagram showing a driving device of a plasma display panel to which the present invention can be applied.

FIG. 3 is a diagram showing a pulse waveform applied to each electrode of the driving device of FIG.

FIG. 4 is a diagram illustrating a driving method of the plasma display panel of the present invention.

[Explanation of symbols]

 1 A / D Converter 3 Frame Memory 4 Sync Separation Circuit 5 Timing Pulse Generation Circuit 6 Memory Control Circuit 7 Output Processing Circuit 8 Address Electrode Driver 9 Write / Erase Control Circuit 10 First Sustain Electrode Driver 11 Second Sustain Electrode Driver

Claims (1)

[Claims] 1. A driving method of a plasma display panel, in which one frame is divided into a plurality of subfields to perform gradation display by modulating the number of times of light emission, and the number of times of light emission of a line at the upper end and / or the lower end of the screen of each subfield is determined. A driving method of a plasma display panel, characterized in that the number of lines is reduced from the line in the center of the screen.