JPH04291392A - Driving device for gas discharge panel - Google Patents

Abstract

PURPOSE:To make fluctuations, generated at border lines of gradations inconspicuous without increasing an address frequency (the number of subfields) while corresponding to a large-capacity panel by a batch write address method. CONSTITUTION:While batch display control over plural odd-numbered lines and even-numbered lines is performed, the display order of the subfields is made different between the odd-numbered lines and even-ordered lines and an odd-numbered line side driver 32 and an even-numbered line side driver 33 are independently controlled in the same frame. The fluctuations can, therefore, be prevented without increasing the number of address lines the number of subfields) in one frame.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a driving device for a gas discharge panel that expresses 2N levels of gradation based on display data of N (N is a natural number) bits. The present invention relates to a driving device for a gas discharge panel that makes fluctuations (flicker, virtual motion) that occur in line boundaries during expression inconspicuous.

In recent years, gas discharge panels that utilize light emitted by AC discharge have been widely used as display devices for personal computers, word processors, etc., and many drive devices for these gas discharge panels have been developed.

FIG. 3 is a block diagram showing an example of a conventional gas discharge panel driving device. In the figure, reference numeral 11 denotes a panel in which a large number of gas discharge electrodes are arranged in a matrix on a glass substrate. 12 is a data side driver, which outputs write pulses, sustain pulses, and
An erase pulse or the like is generated and applied to the panel 11. Further, 13, 14, and 15 are delay circuits, respectively, which delay each bit data of bits 1, 2, and 3 of the display data by delay times TA, TB, and TC (TA<TB<TC) to drive the data side driver. Output to 12. Note that the bit data of bit 0 is inputted as is to the data side driver 12 without being delayed.

[0004] This conventional example displays 2N=24=16 gradations using N=4 bits of display data.
Each bit data of the display data representing six gradations is the above-mentioned bits 0 to 3.

An example of display operation will be described below with reference to FIG. FIG. 4 is a timing chart showing the display operation in FIG. For convenience of explanation, line “1”,
"2", "3", ..., "15", gradation "1", "2"
", "3", ..., "15" shall be displayed. The 4-bit data of each line is input in parallel for each bit. First, in the 4-bit data on the line "1", only the value of bit 0 is "1" and all other bits are "0", and only the data of bit 0 is delayed as shown in Figure 3. The data is directly inputted to the data side driver 12 without any interference. The data side driver 12 causes the panel 11 to display line 1 for the first subfield period immediately from the input time based on the bit data.

[0006] Here, the first subfield period is 4
It is one of the four frames in which the display period of one frame is divided according to the bit display data, and each subfield SF
The display periods are weighted, for example, at 1:2:4:8. That is, bits 0 to 3 are weighted. Therefore, the above-mentioned first subfield period is the above-mentioned 4
Line 1 is displayed only during this first subfield period during one frame period. In this way, 16-level gradation display is performed. In addition,
The gas discharge panel (AC-PDP) 11 has a number of discharges (
The brightness is controlled by the display period).

Next, the 4-bit data of line 2 is input in parallel, but in order to express the gradation level "2", only the value of bit 1 is "1", and the values of other bits are is "0". Therefore, the delay circuit 13
Data with a value of "1" is extracted and input to the data side driver 12.

The data side driver 12 displays the period of the second subfield having the weight of "2" for data after a time TA from the time of data input. Similarly, for data after time TB from the time of data input, the period of the third subfield with a weight of "4" is displayed, and for data after time TC from the time of data input, Then, the period of the fourth subfield, which is the longest and has the weight of "8", is displayed.

Therefore, when inputting data on line 2, the second
The display is performed only during the subfield period. Thereafter, in the same manner as above, as shown in the time chart of FIG. 4, the display (light emission) period of one frame period of each line is determined by the input data of each line input at the time timing indicated by the diagonal line of access line bit 0. The period is shown by the solid line. As shown in the figure, data written with access line bit 0 maintains light emission for the first subfield period until the next access line bit 1, and data written with access line bit 1 continues to emit light on the next access line bit 1. Bit 2
Similarly, the data written in access line bits 2 and 3 are kept emitting light for the third and fourth subfield periods, respectively. Also, for example, the gradation level “15” displayed on line 15 is
'' continues for all of the first to fourth subfield periods, that is, one frame period.

However, in the above conventional method, the gradation levels "7" and "8" are 1 as shown in lines 7 and 8 in FIG.
The display (light emission) period within the frame is reversed. Therefore, line 7 is displayed in most of the first half of one frame, and line 8 is displayed in the second half of one frame.

When the gradation difference (luminance difference) between two adjacent lines is large, the difference in display period within one frame is large, and flicker is not visually noticeable. If "8" is displayed on two adjacent lines, the difference in brightness is small, and as described above, 1
Since the display period in the frame is reversed, the boundary between each line (lines 7 and 8 in FIG. 4) is displayed as a fluctuation in brightness (flicker, phantom movement).

Therefore, there is a need for a gas discharge panel driving device that can make fluctuations (flickers) at the boundaries between adjacent lines less noticeable.

[0013]

[Prior Art] As a conventional drive device for this type of gas discharge panel, for example, there is a
There is something described in Patent Application (2) filed on May 2nd, as shown in FIG.

FIG. 5 is a block diagram showing a conventional example of a driving device for a gas discharge panel that makes flicker less noticeable. In the figure, the same components as those in FIG. 3 are denoted by the same reference numerals, and the explanation thereof will be omitted. In the configuration example shown in FIG. 5, the value of N is "4".
In this case, similarly to the apparatus shown in FIG. 3, 16 gray levels are displayed by selecting each display period of four subfields.

The data selection circuit 20 receives a total of 2 bits of data (bit 2 and bit 3 (MSB)) out of 4 bits of data in parallel, and selects bit 2 data on odd lines based on a line switching signal. The data of bit 3 is selectively output to the delay circuit 21 and the data of bit 3 is selectively output to the delay circuit 22. On the other hand, for even-numbered lines, bit 2 data is selectively output to the delay circuit 22, and bit 3 data is selectively output to the delay circuit 21.

The delay circuit 22 also has delay times TC1 and T
C2 (TC1<TC2), and based on the line switching signal, a delay time TC1 is given to data from the data selection circuit 20 on odd lines, and a delay time TC2 is given on even lines, and the data is output. Here, the above delay time TC1 is the same as the delay time TC of the delay circuit 15 in FIG.

Regardless of whether it is an odd or even line, the data side driver 23 displays the period display of the first subfield with the weight "1" on the panel 11 from the time of input when the data of bit 0 is "1". The point is that when the data input after time TA from the data input point of bit 0 is "1", the period of the second subfield with the weight "2" is displayed from that point onwards. This is the same as the driver 12.

In addition, the data side driver 23 displays the third subfield period of weight "4", which is input after time TB from the data input point of bit 0, on the odd line. When the data input after time TC1 is "1", the fourth subfield period with the weight "8" is displayed from that point onwards. Therefore, on odd lines, 1:2:4:
The first to fourth subfields with a weight of 8 are the first →
The subfields are displayed in the order of second → third → fourth subfields. Therefore, the display timing on odd-numbered lines is the same as the display timing shown in FIG.

On the other hand, on an even number line, if the data input after a time TB from the data input point of bit 0 is "1", the data side driver 23 inputs the fourth subfield with the weight "8" from that point on. Display the period,
When the data input after a time TC2 from the data input time of bit 0 is "1", the panel 11 is caused to display the third subfield period with a weight of "4" from that time. Therefore, on even-numbered lines, the first to fourth subfields are displayed in the order of 1st → 2nd → 4th → 3rd subfield, and the display order of subfields is different on odd-numbered lines. It turns out.

Here, since the presence or absence of display in each of the third and fourth subfields corresponds to the values of bits 2 and 3 of the input data, it is necessary to display the correct gradation according to the value of the input data. In order to display the even-numbered lines, as described above, the data selection circuit 20 inputs the data of bit 3 to the delay circuit 21, and the data of bit 2 is input to the delay circuit 22 with a delay time TC2. The bit arrangement is switched by inputting the data into the .

With this configuration, lines 1, 2, 3
, ..., 15, the gradations are "1", "2", "3", respectively.
...A time chart when "15" is displayed for at least one frame is shown in FIG. In the figure, ■ and ■ indicate the first and second subfields, respectively;
indicate the third and fourth subfields on odd-numbered lines, respectively, and ■ and ■ indicate the third and fourth subfields on even-numbered lines, respectively. Further, a thick solid line indicates a display period.

In FIG. 6, since the display within one frame of gradation level "7" is an odd number line, as shown by the thick solid line a in the figure, each of the first, second and third subfields is displayed as in the conventional case. , ■ and ■. On the other hand, gradation "8"
When displaying within one frame of ``8'' on even lines, only bit 3 of the bits 0 to 3 is ``1'', and data of ``1'' is output from the delay circuit 21.
As shown by the thick solid line b in FIG. 6, the display is performed in the fourth subfield (2) on the even numbered line.

As can be seen from FIG. 6, the third odd line
The display order of the subfield (2) and the fourth subfield (2) of the even-numbered line within one frame is the same, and the display periods within one frame overlap in adjacent lines. Therefore, according to the configuration shown in FIG. 5, even if gradations "7" and "8" are displayed on two adjacent lines, the brightness may visually fluctuate at the boundary line due to overlap within one frame of the display period. (flicker) becomes almost invisible.

[0024]

[Problems to be Solved by the Invention] In such a conventional gas discharge panel driving device, when the number of lines on the panel 11 increases, the number of gradations increases to 2N (the number of subfields N).
Because of the problem of not being able to express gradations, a new driving method was proposed that would be able to express appropriate gradations on high-precision panels that increased the number of lines from about 480 to about 1,000. This new method is called the batch write addressing method and is shown in FIG.

FIG. 7 is a block diagram showing a driving device for a gas discharge panel using the conventional batch write address method. In the figure, the same components as those in FIG. 5 are denoted by the same reference numerals, and the explanation thereof will be omitted. In FIG. 7, bits 0 to 3 are output to the data side driver 31 via the frame memory 30. Furthermore, odd line drivers 32 are provided corresponding to odd lines on the panel 11, and even line drivers 33 are provided corresponding to even lines. The odd and even line side drivers 32, 33 and the data side driver 31 are each controlled by a drive waveform generation circuit 34, and the drive waveform generation circuit 34 outputs each control signal based on a vertical synchronization signal and a horizontal synchronization signal. do.

FIG. 8 is a timing chart showing the display operation in FIG. In the figure, one frame is divided into the first to fourth subfields weighted as described above, and the display periods of the subfields are defined by the odd and even line side drivers 32 and 33. Each subfield causes the gas discharge electrode to emit light in SUS1 to SUS4, but in the period immediately before SUS1 to SUS4, each line is raised by the signal W, and the display period within the field is set by the signal E. As mentioned above, such settings are performed by the odd and even line side drivers 32 and 33, and the SUS1 to SUS
In step 4, a plurality of odd and even lines are collectively displayed. Note that in each subfield, bits 0 to 3 are sequentially output from the data side driver 31. According to such a batch writing address method, since a plurality of lines are collectively displayed and controlled, the reproducibility of gradations is excellent even on the panel 11 having a large number of lines.

Incidentally, even in the gas discharge panel driving device using this batch writing address method, fluctuations occur under the conditions shown in FIG. 4. Therefore, Figure 5
As shown in FIG. 2, it is necessary to prevent fluctuations by making the display order of the N subfields in one frame different between odd-numbered lines and even-numbered lines.

However, the above-mentioned fluctuation prevention measures have been proposed in the prior art in which lines are sequentially scanned, and in a gas discharge panel driving device using the batch writing address method, display control of odd and even lines is performed simultaneously. Therefore, it is difficult to change the display order of subfields for each line, and if this is done, the subfield will be divided into odd and even lines, and each line will be displayed in a different order within each divided area. Processing such as control is required, which makes the process complicated. In addition, in this case, the number of addresses within one frame (number of subfields) increases, so the number of gradations decreases on large-capacity panels that do not have enough address time (display time). There was a problem with this.

[Purpose] Therefore, the present invention provides a gas that makes fluctuations occurring in gradation line boundaries less noticeable without increasing the number of addresses (number of subfields) while supporting large-capacity panels using the batch write addressing method. The purpose of the present invention is to provide a drive device for a discharge panel.

[0030]

[Means for Solving the Problems] In order to achieve the above object, the gas discharge panel driving device according to the present invention displays one frame in response to N (N is a natural number) bits of display data in a display period control section. The period is divided into N subfields, and one of the subfields is divided into N subfields by a weighting circuit.
The display period of each image is weighted in correspondence with the bit digit. The odd lines and even lines of the gas discharge panel are excited by the odd line side driver and the even line side driver, respectively, according to the weighted subfields. Then, the data-side driver applies bit data of the corresponding digit to the odd-numbered lines and even-numbered lines in synchronization with the subfield, thereby collectively controlling the display of the plurality of odd-numbered lines and even-numbered lines. Here, the driver control section changes the display order of the subfields between odd and even lines, and independently controls the odd line side driver and the even line side driver within the same frame. Furthermore, the data in the bit digits is replaced by a bit replacement circuit according to the changed display order of the subfields, so that the arrangement order of the bit data is made different between odd and even lines.

[0031]

According to the present invention, bit data of corresponding digits are applied to odd and even lines in synchronization with weighted subfields, and display of a plurality of odd and even lines is collectively controlled. Here, the display order of the subfields is set to be different for odd lines and even lines by the driver control unit, and the odd line side driver and the even line side driver are independently controlled within the same frame. Further, the data of the bit digits is replaced by a bit replacement circuit according to the display order of the subfields, and the arrangement order of the bit data is set to be different between odd and even lines.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the drawings. 1 and 2 are diagrams showing an embodiment of a gas discharge panel driving device according to the present invention, and FIG. 1 is a block diagram thereof, and FIG.
is the timing chart.

First, the configuration will be explained. In FIG. 1, the same numbers as those given to the conventional example shown in FIG. 7 indicate the same parts. Drive waveform generation circuit 40 as a display period control section
divides the display period of one frame into N=4 subfields corresponding to N=4 bits of display data from bit 0 to bit 3. Further, the drive waveform circuit 40 functions as a weighting circuit and weights the upper digits by making the display period of each subfield correspond to bit digits 0 to 3. Furthermore, the waveform drive circuit 40, as a driver control unit, makes the display order of the subfields different between odd lines and even lines, and makes the odd line side driver 32 and the even line side driver 33 independent within the same frame. control. In this embodiment, as in the conventional example described above, the display order of the third and fourth subfields on even lines is switched, so that the display order on odd and even lines is made different.

The odd line side driver 32 excites the odd lines of the gas discharge panel according to the weighted subfields. The even line side driver 33 also excites the even lines of the gas discharge panel according to the weighted subfields.

The bit switching circuit 41 switches the bit digit data according to the display order of the subfield, and makes the arrangement order of the bit data different between odd and even lines. The data side driver 42 applies bit data of the corresponding digit to the odd and even lines in synchronization with the subfield.

The odd line side driver 32 and the even line side driver 33 collectively control the display of a plurality of odd lines and even lines. Next, the operation will be explained with reference to FIG.

The bit switching circuit 41 selects bits 2 and 3 (MSB) of the 4-bit data on even lines.
Regarding bit 2, based on the subfield control signal (signal indicating exchange of the third and fourth subfields in the even-numbered line) from the drive waveform generation circuit 40,
and frame memory 30 by changing the arrangement order of bit 3.
Output to.

Regarding the first subfield and the second subfield, the data side driver 42 applies bit 0 and bit 1 data to each line with a weighting of 1:2, regardless of whether it is an odd line or an even line. . In the third subfield, the weight is 4 for odd lines.
Bit 2 data is applied at a weight of 8, and bit 3 data is applied at a weight of 8 to even lines. Furthermore, in the fourth subfield, bit 3 data is applied to the odd line with a weight of 8, and bit 2 data is applied to the even line with a weight of 4.

Therefore, in FIG. 2, the display periods of the third and fourth subfields in the odd and even lines are different, and in the odd line, the display period is 1:2: as in the conventional case.
The first to fourth subfields having a weight of 4:8 are displayed in the order of first → second → third → fourth subfields.

On the other hand, on even-numbered lines, the first to fourth subfields are displayed in the order of first → second → fourth → third subfields.

With this configuration, in the gas discharge panel driving device using the batch writing addressing method, the lines 1, 2, 3, . . .
”, “3”, ... “15” in one frame, as in the relationship between lines 7 and 8 shown in Figure 6,
The display periods of adjacent lines can overlap.

That is, the weighting of the subfields is set to 1 corresponding to input data bits 0, 1, 2, and 3, respectively.
:2:4:8, the lighting period of the odd numbered line of SUS3 is 4, the lighting period of the even numbered line is 8, and the lighting period of SUS3 is 4.
In US4, the lighting period of odd and even lines is SUS3
Odd and even line drivers 32
, 33 respectively.

In this way, in this embodiment, since the lighting periods of adjacent lines can be overlapped in the total period of SUS3 and SUS4, the gradation levels of "7" and "7" are displayed on the two adjacent lines.
8'' are displayed, the fluctuation (flicker) at the boundary line of brightness can be made visually almost inconspicuous.

In a gas discharge panel driving device using the batch write addressing method, bit data stored in the frame memory 30 is read out, and bit data having different weights is applied to odd and even lines within the same subfield. Then, based on this bit data, the discharge cells (gas discharge electrodes) of the panel are turned on and off to light up the odd and even lines within a predetermined period. At this time,
The lighting periods of the odd and even lines differ depending on the weight of the bit data, and this weighting is achieved by providing separate control signals for the odd and even line drivers 32 and 33 for the odd and even lines.

In this way, in this embodiment, while controlling the display of a plurality of odd and even lines at once, the display order of the subfields is made different between the odd and even lines, and the odd lines are displayed in the same frame. side driver 32
and the even line side driver 33 are independently controlled. Therefore, fluctuations can be prevented without increasing the number of address lines (number of subfields) within one frame.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that the present invention can be applied to other values than 16, for example, for displaying gradations.

[0047]

[Effects of the Invention] As explained above, according to the gas discharge panel driving device according to the present invention, the number of address lines (number of subfields) in one frame can be increased without increasing the number of address lines (number of subfields) in one frame. Since the driver and the even-numbered line side driver can be controlled independently, one
Display periods in a frame can be overlapped between odd and even lines, and fluctuations can be prevented even when the difference in gradation between adjacent lines is small.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a gas discharge panel driving device according to the present invention.

FIG. 2 is a timing chart showing the operation of the embodiment of FIG. 1;

FIG. 3 is a configuration diagram showing an example of a conventional gas discharge panel driving device.

FIG. 4 is a timing chart showing the display operation in FIG. 3;

FIG. 5 is a configuration diagram showing a conventional example of a driving device for a gas discharge panel that makes flicker less noticeable.

FIG. 6 is a timing chart showing the display operation in FIG. 5;

FIG. 7 is a configuration diagram showing a driving device for a gas discharge panel using a conventional batch write address method.

8 is a timing chart showing the display operation in FIG. 7. FIG.

[Explanation of symbols]

32 Odd line side driver 33 Even line side driver 40 Drive waveform generation circuit (display period control section, weighting circuit, driver control section) 41 Bit switching circuit 42 Data side driver

Claims (1)

[Claims] 1. A display period control unit that divides a display period of one frame into N subfields corresponding to N (N is a natural number) bits of display data, and displays each of the subfields one by one. a weighting circuit that weights the period by bit order, an odd line side driver that excites the odd lines of the gas discharge panel according to the weighted subfields, and an even number side driver that excites the even lines of the gas discharge panel according to the weighted subfields. It includes a line side driver and a data side driver that applies bit data of the corresponding digit to the odd and even lines in synchronization with the subfield, and collectively controls display of a plurality of odd and even lines. In the gas discharge panel driving device, a driver control unit that makes the display order of the subfields different between odd and even lines and independently controls the odd line side driver and the even line side driver within the same frame. , a bit swapping circuit that swaps bit digit data according to the display order of the subfields to make the arrangement order of the bit data different between odd and even lines. Device.