JPH077702A - Plasma display device - Google Patents

Abstract

PURPOSE:To prevent the production of a false contour caused when a moving picture is displayed by driving video signals scatteringly so as to avoid the sequence of luminance. CONSTITUTION:A write control section 3 of a display control section 9 receives a digital image signal to write and store image signal data via an address control section 5 and a data control section 6. When the write of data by one frame is finished, an address decoder 11 of a read control section 10 outputs a read address signal based on a received control signal and reads video signal data from the memory 8 and inputs the data to the control section 6. A sub address counter 12 of the control section 10 counts signals for each period of sub fields in one frame and gives the counted signal to a sub address decoder 13. The decoder 13 provides sub fields in a predetermined sequence so that the scanning of the sub fields is not executed in the order of luminance when a bit selection section 7 selects bits of the video signal to scatter non-display periods.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device, and more particularly to a video signal driving system.

[0002]

2. Description of the Related Art In a conventional AC type plasma display device using a subfield method of the address / display period separation type, as shown in FIG. 4, a video signal of one frame has a relative luminance ratio of 1: 2 :. 4: 8: 16: 32: 6
There are eight subfields of 4: 128, each subfield is composed of an address period and a light emission sustaining period, and the light emission sustaining period is sequentially lengthened to 1: 2: 4: 8: 16: 3.
The video signals are scanned in the luminance order in the order of 2: 64: 128, and the multi-gradation video signal is displayed by the combination of the luminances of the eight subfields. Figure 3
(A)-(C) is explanatory drawing in the case of displaying the moving image by a prior art example. As shown in FIG. (A), when the image on the left side of the image is dark and the right side of the image is bright, the image level moves slowly to the left in the center of the screen. Assume that the level has changed to 128. As shown in FIG. 7B, the sub-frames are scanned in the order of luminance from sub-frame (SF) 1 to 8, and if an 8-bit signal is used as an image signal, 127 Level is 01
Quantized by 111111, 128 levels are 1000
It is quantized by 0000. Therefore, as shown in FIG. 6C, at the 127 level, SF1 to SF7 are the display period, and in the next frame, SF8 is the display period, and the image is displayed.

[0003]

Therefore, when a moving image as described above is displayed, the non-display period becomes one frame, which is a relatively long period. Therefore, the non-display period becomes a black line in the image. However, there is a problem that a so-called false contour appears. According to the present invention, a video signal is dispersed and driven so as not to be in a luminance order, and even when a moving image as described above is displayed, it is dispersed so that a non-display period does not continue for a long period of time. The purpose is to prevent the generation of contours.

[0004]

In a plasma display device of the present invention, a plurality of subfields having different luminance relative ratios and light emission sustaining periods constitute one frame to display a multi-gradation video signal. It is characterized in that the display device is provided with a means for distributing and scanning the sub-fields so that the sub-fields are not scanned in the order of luminance.

[0005]

According to the present invention, with the above-described structure, it is provided with means for distributing and scanning the sub-fields so that the sub-fields are not scanned in the luminance order, and even when a moving image is displayed, the non-display period is not dispersed for a long period of time. Therefore, it is possible to prevent the occurrence of false contours.

[0006]

1 is a block diagram showing an embodiment of the plasma display device of the present invention. Vertical sync extracted by inputting a digital video signal (RGB signal) input to the write control unit 3 of the display control unit 9 via the input terminal 1 and separating and extracting the clock control signal, the blanking signal and the video signal input as the display control signal. The signal and the horizontal synchronizing signal are input to the display control unit 9 via the input terminal 2. The write control unit 3 outputs a write address signal according to the control signal and inputs it to the address control unit 5 of the I / O buffer unit 4, and also inputs the input video signal to the data control unit 6, and the address control unit The video signal data from the data control unit 6 is written and stored in the frame memory (DRAM module) 8 in accordance with the address signal input from 5.

When the writing of the video signal data for one frame is completed, the address decoder 11 of the read controller 10 outputs a read address signal based on the input control signal and inputs it to the address controller 5. The video signal data is read from the frame memory 8 and input to the data control unit 6. The sub-address counter 12 of the read control unit 10 detects the sub-field, SF1 in one frame.
Up to SF8 are counted and a count signal is output, and the count signal is output by the sub-address decoder 13 in a predetermined sub-field order.

FIGS. 2A and 2B are explanatory views showing an embodiment of a video signal driving system of the present invention. Figure (A)
Indicates the order of sub-fields constituting one frame. SF8 is arranged in the approximate center of the frame, SF7 is arranged at the beginning of the frame, SF6 is arranged at the end of the frame, and SF1 to SF5 are distributed between them. Make sure that the numbers up to are not adjacent and SF7, 5, 3, from the beginning of the frame.
Subfields are dispersed and arranged in the order of 1, 8, 2, 4, and 6. The output of the sub-address decoder 13 is input to the bit selection unit 7 of the I / O buffer unit 4, and the frame memory 8
The video signal data read from is input to the bit selection unit 7 via the data control unit 6.

The bit selection section 7 selects a bit of the video signal data and inputs it to the address drivers 15 and 16,
The display address control unit 14 of the display control unit 9 generates an address signal based on a control signal input via the input terminal 2 and inputs the address signal to the address drivers 15 and 16, and the address drivers 15 and 16 use the video signal. The signal data is written in a designated address portion of the plasma display panel 17 so that a video signal is displayed. Explaining that the video signal data is quantized by 8 bits, in the period of SF7 in FIG. 2A, the bit in the seventh digit is selected and output by the bit selection unit 7, and in the period of SF5, 5 bits are selected. The bit of the digit is selected and output by the bit selecting unit 7, the bit of the third digit is selected and output by the bit selecting unit 7 during the period of SF3, and the bit of the LSB is selected during the period of SF1. The selection unit 7 selects and outputs the bit, the MSB bit is selected and output by the bit selection unit 7 during the SF8 period, and the second digit bit is selected by the bit selection unit 7 during the SF2 period. The bit selector 7 selects and outputs the fourth digit bit during the period SF4, and the bit selector 7 selects and outputs the sixth digit bit during the period SF6.

Therefore, when a moving image as shown in FIG. 3 (A) is displayed, the level 127 is SF7, SF5, SF in the first frame as shown in FIG. 2 (B).
3, SF1 and SF2, SF4, and SF6 are display periods. In the next frame, only SF8 is a display period, and the non-display period is distributed to three places. Therefore, since the non-display period is dispersed and the duration of each non-display period is shortened, it becomes difficult to visually recognize the non-display period, and it is possible to prevent false contours from appearing in the moving image. The arrangement of each sub-field shown in FIG. 2A is an example, and sub-fields having a long relative luminance ratio and a long light emission sustaining period (large sub-field numbers) may be appropriately dispersed and arranged. The left and right sides may be replaced with each other, or the SF8 may be arranged so as to be displaced from the central portion for scanning.

[0011]

As described above, according to the present invention,
By driving the plasma display panel by dispersing the video signals so that they are not in the luminance order, it is possible to disperse the non-display period that occurs when a moving image is displayed and to prevent the occurrence of false contours. A display device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a plasma display display device of the present invention.

2A and 2B are explanatory diagrams showing an embodiment of a video signal driving method according to the present invention.

3A to 3C are explanatory diagrams for displaying a moving image according to a conventional example.

FIG. 4 is an explanatory diagram showing a conventional video signal driving method.

[Explanation of symbols]

 1 Input Terminal 2 Input Terminal 3 Write Control Section 4 I / O Buffer Section 5 Address Control Section 6 Data Control Section 7 Bit Selection Section 8 Frame Memory 9 Display Control Section 10 Read Control Section 11 Address Decoder 12 Sub Address Counter 13 Sub Address Decoder 14 Display Address control unit 15 Address driver 16 Address driver 17 Plasma display panel

Claims (3)

[Claims] 1. In a plasma display device displaying a multi-gradation video signal by constructing one frame with a plurality of sub-fields having different luminance relative ratios and light emission sustaining periods, the sub-fields are not scanned in order of luminance. A plasma display device, characterized in that it is provided with a means for dispersing and scanning the light. 2. The means for scanning the sub-fields in a dispersed manner so that the sub-fields are not scanned in the order of luminance, controls means for designating the order of the sub-fields, and bits of the video signal read from the storage section by an input from the control means. 2. A plasma display display device according to claim 1, further comprising a bit selection means for selecting, and displaying a video signal on the plasma display display device based on an output from the bit selection means. 3. A means for scanning the sub-fields in a distributed manner so that the sub-fields are not scanned in the luminance order, the control means for designating the sub-field order, and the bit of the video signal read from the storage section by the input from the control means. The MSB bit of the video signal becomes substantially the center of the frame by the bit selecting means for selecting, and the second digit (second) and the third digit of the MSB are set to the beginning of the frame. 2. The plasma display device according to claim 1, wherein scanning is performed in the order of the one toward the end or the end.