JP2765154B2 - Driving method of plasma display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dot matrix type plasma used in personal computers and office workstations, which are remarkably progressing in recent years, or wall-mounted televisions which are expected to develop in the future. The present invention relates to a method for driving a display panel.

[Conventional technology]

FIG. 7 shows a structural example of a conventional plasma display panel. 7A is a plan view, and FIG. 7B is a sectional view taken along the line aa 'of FIG. In FIG. 7, 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 SnO ₂ or ITO, or a thick silver film,
4 is a striped column electrode, 5 and 6, which is also made of SnO ₂ , ITO, or a thick silver film, and is formed in a direction orthogonal to the row electrode 3.
Is an insulating layer made of thick glass, 7 is a protective layer made of MgO or the like, 8 is a discharge space in which a discharge gas in which He is mixed with Xe by several%, 9 is a phosphor, 10 is a partition separating pixels, 11 Is a pixel. FIG. 8 shows the overall configuration of this plasma display panel. Row electrodes 3 are two groups in FIG. 8, i.e. common and scanning electrodes S ₁ to S _m row electrodes C ₁ ~C _{m + 1}
Divided into Reference numeral 12 denotes a seal portion made of a low-melting glass or the like that bonds the first insulating substrate 1 and the second insulating substrate 2 together.

The arrangement of the phosphors is schematically shown in FIG. 9A. This is a phosphor array called a so-called triangular pixel array. In this arrangement, since one color pixel of three colors has a shape as shown in FIGS. 9B and 9C, two rows of pixels constitute one unit row of color display.

An example of the driving waveform of this plasma display panel is shown in FIG.
Figure 10 shows. Negative sustain pulse is commonly applied to the common row electrode C ₁ ~C _{m + 1.} Also the scanning electrodes S ₁ to S _m, in addition to the common negative sustain pulse to any electrode, independently of each scanning electrode, a scanning panel and erase panel line-sequentially applied. Further, a positive pulse voltage is applied to the column electrodes according to the emission data. For example, to emit the intersection of the pixel of the scanning electrode S ₁ and the column electrodes D _1, applying a positive pulse to the column electrodes D ₁ in synchronization with the scan pulse applied to the scan electrodes S ₁ as FIG. 10 I do. Then, a discharge is generated in this pixel, and light emission is generated. This discharge light emission sustain pulse is maintained by being applied, the erase pulse of narrow scan electrodes S ₁ a low voltage is applied, discharge light emission is stopped. By such means, light emission of each pixel can be controlled over the entire screen.

As it can be seen from the description of FIG. 8 pulse configuration and the driving waveform of FIG. 10, for example, the arrangement of pixels in two rows, including a scanning electrode S ₁ at the timing of the write pulse applied to the scan electrodes S ₁ At the same time, the start of light emission is controlled, and the light is simultaneously turned off at the timing of the erase pulse. That is, the light emission states of the pixels arranged in two rows are simultaneously controlled. This corresponds to the fact that one unit row of the color display is composed of two rows of pixels as shown in FIG.

Next, a gradation display method will be described. By controlling the number of times of light emission using the driving waveform as shown in FIG. 10, gradation display can be performed. That is, a so-called one-field period for displaying one screen is divided into subfields, and the number of times of light emission in each subfield is changed, so that the plasma display can perform gradation display. A time chart in this case is shown in FIG. No.
In FIG. 11, the horizontal axis indicates time, the vertical axis indicates the position of each scanning electrode, and the hatched portion indicates a time zone in which light emission is possible. 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 in one unit row of color display are written simultaneously. This timing is the write timing, and since each row is sequentially written, the write timing shifts for each row. Similarly, the timing of erasing the state written in line-sequential and stopping the light emission is the erasing timing.

By the way, the number of light emission in each subfield is set to be 2 ⁿ times. Therefore, the brightness B of a certain dot
In the example of FIG. 10 becomes _{^{B = 2 8 x 1 +2 7}} x 2 +2 5 x 3 +2 5 x 4 +2 4 x 5 +2 3 x 6. Wherein x ₁ ~x ₆ are variables take values 1 or 0 to the weighting of the luminance. Therefore, the luminance B can take a value of 2 ⁶ = 64 levels, which is the number of combinations of x ₁ to x ₆ . That is, display of 64 gradations is possible.

[Problems to be solved by the invention]

However, when a plasma display is driven by using such a gradation control method, if a non-lighting state (= non-discharge state) of a certain pixel is long, ions or ions which are present in the pixel and serve as discharge seeds are present. The electrons and recombination disappear, and the discharge starting voltage becomes abnormally high. Therefore, even if a non-lighting state is continued for a long time, even if a pulse voltage for starting light emission is applied to discharge light suddenly, discharge does not occur immediately. There was a point.

An object of the present invention is to realize a driving method of a plasma display without such an ignition error.

[Means for solving the problem]

According to the present invention, an AC-type dot matrix type plasma display panel is used, wherein one field period for displaying one screen is divided into a plurality of sub-fields, and the number of times of light emission in each sub-field is set to a predetermined value. In the method for driving a plasma display panel, a method for driving a plasma display is provided in which a specific period for performing preliminary discharge for all cells is provided for each of a plurality of selected subfields.

[Action]

The present invention has solved the problems of the prior art by using the above configuration. That is, unlike FIG. 11, as shown in FIG. 1, a sub-field for preliminary discharge is provided separately from that for gradation display, and pre-discharge is performed in all pixels within the period of this sub-field. By doing so, ions and electrons always stay in each pixel. Therefore, when a pulse voltage for starting the discharge is applied, the staying ions and electrons act as a trigger for starting the discharge, so that an ignition mistake does not occur.

The preliminary discharge does not necessarily need to be performed for each field, and a sufficient effect can be obtained even by performing the preliminary discharge once in several fields. Hereinafter, a specific example of the preliminary discharge method will be described in detail.

Embodiment 1 FIG. 2 shows driving waveforms during a pre-discharge subfield period according to 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, 4 μs, and 1 μs, respectively. These values are common to all subfields. The plasma display panel used in the experiment is the same as that described in the conventional example, and the number m of scanning electrodes is 120,
The number n of column electrodes is 480.

The operation of the first to sixth subfields is the same as that of the conventional example, and the description is omitted. The basic operation of the pre-discharge method according to the present embodiment is similar to the first operation shown in FIG.
Unlike the operation of the sixth to sixth subfields, unlike the conventional example of FIG. 10, in the present embodiment of FIG. 2, an erasing pulse is inserted immediately after the scanning pulse. In addition, all the column electrodes D _j (j
= 1 to 480), a data pulse for lighting a pixel is inserted. Thus, for example, in any pixel that is controlled by the scanning electrode S _1, discharge emission waveform is a second view lowermost waveform.

By performing such a preliminary discharge, it is possible to eliminate a lighting mistake when a pixel that has not been lit for a long time is suddenly lit. Moreover, the basic driving method is
There is an advantage that it can be easily realized because it is not different from other subfields that perform light emission control.

In the present embodiment, sustain pulse applied to the scan electrodes S ₁ to S _120, since not directly related to the preliminary discharge operation,
The operation may be stopped during the pre-discharge subfield period. Although the data pulse is applied to the column electrode, the pulse is not necessarily required to be a pulse, but may be maintained at a high voltage during the predischarge subfield as described in the second embodiment. Alternatively, without applying the data voltage,
The scan pulse voltage may be increased only during the predischarge subfield.

[Embodiment 2] FIG. 3 is a driving waveform during a pre-discharge subfield period according to a second embodiment of the present invention. The operations in the first to sixth subfields for performing the gradation display control are the same as those in the first embodiment.

This embodiment is largely different from the first embodiment is that the sustain pulses are applied is in the common sustain electrode C ₁ -C ₁₂₁ during the preliminary discharge period is in the erase pulse width 1 [mu] s.
As a result, as shown in the lowermost part of FIG. 3, the number of times of discharge light emission of the preliminary discharge was two, and the light emission intensity by the preliminary discharge was further weakened as compared with the first embodiment. Therefore, there is an effect that the contrast of the screen is further improved.

Although a constant voltage is applied to all the column electrodes during the predischarge subfield, it goes without saying that a data pulse may be applied similarly to FIG.

In FIG. 3, sustain pulses are continuously applied to all scan electrodes. However, since these sustain pulses are not directly related to the preliminary discharge operation, they may be stopped during the preliminary discharge subfield period. .

[Embodiment 3] FIG. 4 shows driving waveforms during a pre-discharge subfield period according to a third embodiment of the present invention. The operations in the first to sixth subfields for performing the gradation display control are the same as those in the first embodiment.

This embodiment differs from the second embodiment in that the erase pulse applied to the common row electrode is limited to the common row electrodes on both sides of the scan electrode to which the scan pulse is applied, as shown in FIG. That is. For example, the case of applying a scanning pulse to the scanning electrodes S _1, is applied only erase pulse to the common row electrode C ₁ and C ₂ on both sides of the scanning electrode S ₁ is followed pull thereto. Discharge light emission waveform of the pixel at this time on the scanning electrode S ₁ is as bottom Figure 4. At this time, the pixels on the other scanning electrodes do not emit light.

By using such a drive waveform, unnecessary erasing pulses are not applied, and power consumption accompanying the erasing pulse application can be reduced. Also, by removing the sustain pulse applied to the scan electrode, the power consumption accompanying the application of the sustain pulse could be reduced. As described above, the power consumption due to the preliminary discharge can be reduced.

Embodiment 4 FIG. 5 shows a driving waveform in a preliminary discharge period according to a fourth embodiment of the present invention. The operations in the first to sixth subfields for controlling the light emission are the same as those in the first embodiment.

In the present embodiment, the preliminary discharge is performed simultaneously and collectively on all the screens. At this time, the width of the scan pulse and the data pulse is 20 μs, and the erase pulse applied to the common row electrode is 1 μs.
s width.

Since the preliminary discharge is performed on the entire surface at once,
The time spent in the pre-discharge period can be greatly reduced as compared with the first, second and third embodiments. Therefore, when the number of subfields for light emission control is increased in order to perform finer gradation display, it is particularly advantageous in terms of time.

In addition, if the preliminary discharge is performed on the entire surface in this way, a considerably large discharge current flows, so that a large-capacity power supply is required. In such a case, the entire screen may be divided into several groups, and the preliminary discharge may be performed collectively for each group.

Also, different from the present embodiment, the pre-discharge may be performed first between the common row electrode and the column electrode by changing the voltage applied to the common row electrode and the scan electrode, and then the erase pulse voltage may be applied to the scan electrode.

Further, in the present embodiment, the first preliminary discharge is performed between the scan electrode and the column electrode, but unlike this, no voltage is applied to the column electrode, and a voltage pulse is applied only to the scan electrode side. Good. FIG. 6 shows such an example. In FIG. 6, a pre-discharge is generated by applying a common scan pulse to all the scan electrodes, and then the pre-discharge is stopped by applying an erase pulse to all the common row electrodes.

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

In the embodiment described above, the preliminary discharge is performed by providing one preliminary discharge period in one field. However, the preliminary discharge does not necessarily need to be performed for each field.
Even one preliminary discharge in the field is effective in preventing lighting errors.

In the embodiment described above, the plasma display panel shown in FIGS. 7 to 9 has been described as an example. However, such a plasma display panel is not necessarily required to be a so-called AC type plasma display panel. The driving method of the present invention is applicable to any type of display panel.

In the above-described embodiment, the number of subfields for gradation control is described as 6. However, the number of subfields is not limited to six, and it is needless to say that two or eight subfields may be used.

〔The invention's effect〕

As described above, by using the present invention, it is possible to obtain a driving method of a plasma display panel that can perform gradation display without causing lighting errors. Therefore, it is possible to obtain a plasma display with very good tone reproducibility and high display quality with good color and form reproducibility,
Very useful industrially.

[Brief description of the drawings]

FIG. 1 is a time chart provided with a pre-discharge subfield according to the present invention, and FIGS. 2 to 5 are diagrams showing respective drive waveforms of the first to fourth embodiments for performing a pre-discharge according to the present invention. FIG. 6, FIG. 6 is a diagram showing driving waveforms in a different form of the fourth embodiment of the present invention, FIG. 7 is a plan view and a sectional view showing an example of a plasma display panel, and FIG. FIG. 9 shows the overall configuration of the plasma display panel, FIG. 9 shows the color pixel arrangement of the plasma display panel of FIG. 7, FIG. 10 shows the driving waveform of the plasma display panel, and FIG. 6 is a time chart of one field period when performing grayscale display on a plasma display panel by a conventional driving method. 1,2 ... insulating substrate, 3 ... row electrode, 4 ... column electrode, 5,6 ...
... an insulating layer, 7 ... a protective layer, 8 ... a discharge space, 9 ... a phosphor, 10 ... a partition, 11 ... a pixel.

Claims (1)

(57) [Claims] An AC-type plasma using an AC-type dot matrix type plasma display panel, dividing one field period for displaying one screen into a plurality of sub-fields, and setting the number of times of light emission in each sub-field to a predetermined value. A method for driving a display panel, comprising: providing a specific period for performing a preliminary discharge for all cells in each of a plurality of selected subfields.