JPH04280289A - Drive method of plasma display panel - Google Patents

Abstract

PURPOSE:To prevent an ignition error due to the action of ions or electrons as a trigger to start a discharge process by providing pre-discharge sub-field, and causing charged particles or the like to reside in a discharge cell at all times. CONSTITUTION:In addition to pre-discharge sub-field for the display of gradation, another pre-discharge sub-field A is provided and pre-discharge is carried out in all picture elements within the required time. As a result, ion and electron come to reside in each picture element at all times. When discharge start pulse voltage is applied to the element, therefore, the residual ions or electrons act as a trigger to start a discharge process. In this case, for example, an erase pulse C is inserted immediately after a scanning pulse E, and all line electrodes Dj (j=1 to 480) are applied with data pulses D for lighting the picture elements. In any picture element controlled with a scanning electrode Si, therefore, a discharge luminous waveform is, for example, as shown in the lowest line of the illustration. By performing the pre-discharge as aforementioned, it becomes possible to eliminate an error in suddenly lighting a picture element not lit for a long time.

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 dot matrix type plasma display panel used in personal computers and office workstations, which have been rapidly progressing in recent years, and wall-mounted televisions, which are expected to develop in the future.

0002

2. Description of the Related Art An example of the structure of a conventional plasma display panel is shown in FIG. In FIG. 8, (A) is a plan view, (
B) Figure is a sectional view taken along line a-a' in Figure (A). In FIG. 8, 1 is a first insulating substrate made of glass or the like, 2 is a second insulating substrate made of glass or the like, 3 is a striped row electrode made of SnO2, ITO, or a thick film of silver, and 4 is SnO2.
2, a striped column electrode made of thick film of ITO, silver, etc., and made in a direction perpendicular to the row electrode 3; 5 and 6 are insulating layers made of thick film glass, etc.; 7 is a protection layer made of MgO, etc. layer, 8 is a discharge space in which a discharge gas containing several percent of Xe mixed with He, 9 is a phosphor, 10 is a partition wall that separates pixels, 11
is a pixel. FIG. 9 shows the overall configuration of this plasma display panel. In FIG. 9, the row electrodes 3 are divided into two groups: scan electrodes S1 to Sm and common row electrodes C1 to Cm+1. Also, 12 is the first
This is a sealing portion made of low melting point glass or the like that bonds the insulating substrate 1 and the second insulating substrate 2 together.

[0003] The arrangement of phosphors is schematically shown in FIG. 10(A). This is a phosphor array called a so-called triangular pixel array. In this arrangement, one unit of color pixels of three colors has a shape as shown in FIGS. 10B and 10C, so two rows of pixels form one unit row of color display.

FIG. 11 shows an example of the driving waveform of this plasma display panel. Common row electrode C1 ~ Cm+1
A negative sustain pulse is commonly applied to. Furthermore, in addition to the negative sustain pulse common to all electrodes, a scan pulse and an erase pulse are independently applied to each scan electrode in a line-sequential manner to the scan electrodes S1 to Sm. Furthermore, a positive pulse voltage is applied to the column electrodes according to the light emission data. For example, to cause a pixel at the intersection of scan electrode S1 and column electrode D1 to emit light, a positive pulse is applied to column electrode D1 in synchronization with a scan pulse applied to scan electrode S1, as shown in FIG. Then, a discharge occurs within this pixel, causing light emission. This discharge light emission is maintained by applying a sustain pulse, but when a narrow low voltage erase pulse is applied to the scan electrode S1, the discharge light emission stops. With such means, each pixel can control light emission over the entire screen.

As can be seen from the panel configuration in FIG. 9 and the explanation of the drive waveform in FIG. The start of light emission is controlled, and the light is turned off at the same time as the erase pulse. That is, the light emitting states of the pixels arranged in two rows are controlled simultaneously. This corresponds to the fact that one unit row of color display consists of two rows of pixels, as shown in FIG.

Next, the gradation display method will be explained. Figure 11
Gradation display can be performed by controlling the number of times of light emission using a drive waveform as shown in FIG. That is, by dividing a so-called one field period in which one screen is displayed into subfields and changing the number of times of light emission in each subfield, it is possible to cause the plasma display to display gradations. A time chart in this case is shown in FIG. In FIG. 12, the horizontal axis shows time, the vertical axis shows the position of each scanning electrode, and the shaded area shows the time period in which light can be emitted. In this example, one field period is divided into six subfields. In each subfield, writing is performed by so-called line sequential scanning in which pixels of one unit row of color display are written simultaneously. This timing is the write timing, and since each row is written in sequence, the write timing shifts from row to row. Similarly, the erasing timing is the timing at which the line-sequentially written state is erased and the light emission is stopped.

By the way, the number of times of light emission in each subfield is set to 2n times. Therefore, in the example of FIG. 11, the brightness B of a certain dot is

[0008]

[0009] Here, x1 to x6 are variables that weight the brightness and take a value of 1 or 0. Therefore, the brightness B is the number of combinations of x1 to x6 26 = 6
It can take four levels of values. In other words, display with 64 gradations is possible.

0010

[Problems to be Solved by the Invention] However, when a plasma display is driven using such a gradation control method, if a certain pixel remains in a non-lighting state (=non-discharge state) for a long time, the The ions and electrons that form the seeds of the discharge recombine and disappear, resulting in an abnormally high discharge starting voltage. Therefore, even if you apply a pulse voltage to start emitting light after a long period of non-lighting, the discharge will not occur immediately.
There was a problem in that pixels that were supposed to light up did not light up due to an ignition error.

An object of the present invention is to realize a method for driving a plasma display that is free from such ignition errors.

0012

[Means for Solving the Problems] According to the present invention, one field period for displaying one screen is divided into a plurality of subfields in order to display gradation using an AC dot matrix type plasma display panel. However, in a method for driving a plasma display panel that performs gradation display by setting the number of times of light emission in each subfield to a different value, at least one subfield per field or one subfield per several fields is used in addition to the gradation display. A method for driving a plasma display panel is obtained, which is characterized in that a field is provided and a preliminary discharge is caused to occur within the period of this subfield.

[0013]

[Operation] The present invention solves the problems of the prior art by using the above-described structure. That is, unlike the conventional example shown in FIG. 12, as shown in FIG. 1, a subfield for preliminary discharge is provided separately from the subfield for gradation display, and preliminary discharge is caused to occur in all pixels within the period of this subfield. By doing so, ions and electrons always stay in each pixel. Therefore, when a pulse voltage for starting discharge is applied, the accumulated ions and electrons act as a trigger for starting discharge, and ignition errors no longer occur. A specific example of the preliminary discharge method will be described in detail below.

[0014]

Embodiment 1 FIG. 2 shows drive waveforms during a preliminary discharge subfield period in a first embodiment of the present invention. Here, the period of the sustain pulse is approximately 18.6 μs, and the sustain pulse width, scan pulse width, data pulse width, and erase pulse width are 5 μs, 4 μs, and 4 μs, respectively.
, 1 μs. These values are common to all subfields. The plasma display panel used in the experiment was the same as that described in the conventional example, and the number m of scanning electrodes was 120, and the number n of column electrodes was 480.

The operations of the first to sixth subfields are the same as in the conventional example, and therefore their explanation will be omitted. The basic operation of the pre-discharge method of this embodiment is the same as the operation of the first to sixth subfields for normal light emission control shown in FIG.
Unlike the conventional example shown in FIG. 11, in this embodiment shown in FIG. 2, an erase pulse is inserted immediately after the scan pulse. Further, data pulses for lighting pixels are inserted into all column electrodes Dj (j=1 to 480). Therefore, for example, in any pixel controlled by the scan electrode S1, the discharge light emission waveform becomes the waveform shown in the bottom row of FIG.

By performing such a preliminary discharge, it has become possible to eliminate lighting mistakes when suddenly lighting a pixel that has not been lit for a long time. Moreover, since the basic driving method is the same as in other subfields that perform light emission control, there is an advantage that it can be easily realized.

Note that in this embodiment, scanning electrodes S1 to S
Since the sustain pulse applied to 120 is not directly related to the pre-discharge operation, it may be stopped during the pre-discharge subfield period. Furthermore, although data pulses are applied to the column electrodes, they do not necessarily have to be pulses, and may simply be maintained at a high voltage during the pre-discharge subfield as described in the second embodiment. Alternatively, the scanning pulse voltage may be increased only during the preliminary discharge subfield without applying the data voltage.

Embodiment 2 FIG. 3 shows drive waveforms during a preliminary discharge subfield period in a second embodiment of the present invention. Note that the operations of the first to sixth subfields for performing gradation display control are the same as in the first embodiment.

The major difference between this embodiment and the first embodiment is that the common sustain electrodes C1 to C121 are connected to each other during the preliminary discharge period.
The sustain pulse applied to is an erase pulse with a width of 1 μs. As a result, as shown in the bottom row of FIG. 3, the number of times of discharge light emission in the preliminary discharge became two, and the light emission intensity due to the preliminary discharge became even weaker than in the first example. Therefore, there was an effect that the contrast of the screen was further improved.

Although a constant voltage was applied to all column electrodes during the pre-discharge subfield, it goes without saying that data pulses may also be applied as in FIG. 2. do not have.

Furthermore, although sustain pulses are continuously applied to all scanning electrodes in FIG. 3, these sustain pulses are not directly related to the preliminary discharge operation, so they are stopped during the preliminary discharge subfield period. Good too.

Embodiment 3 FIG. 4 shows drive waveforms during a preliminary discharge subfield period in a third embodiment of the present invention. Note that the operations of the first to sixth subfields for performing gradation display control are the same as in the first embodiment.

This embodiment is different from the second embodiment in that the erase pulse applied to the common row electrode is applied to the common row electrodes on both sides of the scan electrode to which the scan pulse is applied, as shown in FIG. It is limited. For example, if a scan pulse is applied to scan electrode S1, then scan electrode S
The erase pulse is applied only to the common row electrodes C1 and C2 on both sides of the cell. At this time, the discharge light emission waveform of the pixel on the scanning electrode S1 becomes as shown in the bottom row of FIG. At this time, pixels on other scanning electrodes do not emit light.

By using such a drive waveform,
Unnecessary erasing pulses are not applied, and power consumption associated with erasing pulse application can be reduced. Furthermore, by removing the sustain pulses that had been applied to the scan electrodes, power consumption associated with the application of sustain pulses could also be reduced. As a result of the above, it was possible to reduce power consumption associated with preliminary discharge.

Embodiment 4 FIG. 5 shows drive waveforms during the preliminary discharge period in a fourth embodiment of the present invention. Note that the operations in the first to sixth subfields for controlling light emission are the same as in the first embodiment.

In this embodiment, preliminary discharge is simultaneously performed on the entire screen. At this time, the width of the scan pulse and the data pulse was 20 μs, and the width of the erase pulse applied to the common row electrode was 1 μs.

Since the preliminary discharge is performed all at once over the entire surface in this manner, the time spent in the preliminary discharge period can be greatly reduced compared to the first, second, and third embodiments. Therefore, it is advantageous especially in terms of time when the number of subfields for light emission control is increased in order to display finer gradations.

[0028] If preliminary discharge is performed all at once in this way, a large capacity power source is required to flow a considerably large discharge current. In such a case, the entire screen may be divided into several groups and preliminary discharge may be performed for each group at once.

Furthermore, unlike this embodiment, the voltage applied to the common row electrode and the scan electrode may be switched, a preliminary discharge is first performed between the common row electrode and the column electrode, and then an erase pulse voltage is applied to the scan electrode. good.

Further, in this example, the first preliminary discharge was performed between the scanning electrode and the column electrode, but unlike this, no voltage was applied to the column electrode, and a voltage pulse was applied only to the scanning electrode side. You may. Such an example is shown in FIG. In FIG. 6, a common scan pulse is applied to all scan electrodes to generate a preliminary discharge, and then an erase pulse is applied to all common row electrodes to stop the preliminary discharge.

In this embodiment, the width of the erase pulse is set to 1μ.
Although so-called narrow width erasing is performed as s, the invention is not limited to this, and so-called wide erasing may be performed using a wider erasing pulse.

Further, in the embodiments described above, preliminary discharge was performed by providing one preliminary discharge period in one field, but it is not necessarily necessary to perform preliminary discharge for each field.
For example, preliminary discharge may be performed once every four fields.

[0033] Also, on the contrary, there are two
It is also possible to more effectively prevent lighting errors by performing preliminary discharge more than once. A time chart in this case is shown in FIG. In FIG. 7, two preliminary discharge subfields are provided during one field period. Note that the preliminary discharge method was an entire-surface batch method as shown in FIGS. 5 and 6.

Furthermore, in the embodiments described above, the plasma display panels shown in FIGS. The driving method of the present invention can be applied to any type of plasma display panel.

Further, in the embodiments described above, the number of subfields for gradation control has been described as six, but it is needless to say that the number is not necessarily limited to this, and may be two subfields or eight subfields, for example.

[0036]

As described above, by using the present invention, it is possible to obtain a method of driving a plasma display panel capable of displaying gradations without causing lighting errors. Therefore, it is possible to obtain a high-quality plasma display with very good gradation reproducibility, good color and shape reproducibility, and it is very useful industrially.

[Brief explanation of the drawing]

FIG. 1 is a time chart in which a preliminary discharge subfield of the present invention is provided.

FIG. 2 is a diagram showing drive waveforms in a first embodiment of the present invention that performs preliminary discharge.

FIG. 3 is a diagram showing drive waveforms of a second embodiment of the present invention that performs preliminary discharge.

FIG. 4 is a diagram showing drive waveforms of a third embodiment of the present invention that performs preliminary discharge.

FIG. 5 is a diagram showing driving waveforms of a fourth embodiment of the present invention that performs preliminary discharge.

FIG. 6 is a diagram showing different driving waveforms in a fourth embodiment of the present invention.

FIG. 7 is a time chart when two preliminary discharge subfields of the present invention are provided in one field.

8A and 8B are diagrams showing an example of a plasma display panel, in which FIG. 8A is a plan view and FIG. 8B is a sectional view taken along line aa' in FIG.

9 is a diagram showing the overall configuration of the plasma display panel shown in FIG. 8. FIG.

FIG. 10 is a diagram showing the color pixel arrangement of the plasma display panel in FIG. FIG. 3 is a diagram showing color pixels.

FIG. 11 is a diagram showing driving waveforms of a plasma display.

FIG. 12 is a time chart of one field period when gradation display is performed on a plasma display panel using a conventional driving method.

[Explanation of symbols]

1 First insulating substrate 2 Second insulating substrate 3 Row electrode 4 Column electrode 5, 6 Insulating layer 7 Protective layer 8 Discharge space 9. Phosphor 10 Partition wall 11 pixels 12 Seal part

Claims (1)

[Claims] 1. A plasma display panel that uses an AC dot matrix type plasma display panel, divides one field period for displaying one screen into a plurality of subfields, and sets the number of times of light emission in each subfield to a different value. A plasma display characterized in that, in the driving method, at least one subfield is provided separately from that for gradation display, or one subfield is provided in several fields, and a preliminary discharge is caused to occur within the period of this subfield. How to drive the panel.