JPH11296136A - Driving method of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the plasma display panel, which has a high picture quality and a low cost by stabilizing the discharge during a writing interval. SOLUTION: Bias voltage pulses are applied to data electrodes 141 to 14M and writing pulses are superimposed to realize a stable writing and a high quality picture display. To realize the above, the data electrode driving circuit is constituted of a data electrode selection driving circuit 31 and a bias voltage pulse applying circuit 32. Thus, the high picture quality plasma display panel is realized at a low cost while the discharging delay during a writing discharge is improved, the malfunction in writing is greatly reduced and the deterioration in contrast is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a circuit for driving a plasma display panel used for displaying images on computers and televisions, and more particularly, to a plasma display which facilitates data writing and realizes high quality panels. The present invention relates to a panel driving method.

[0002]

2. Description of the Related Art In recent years, expectations for high-definition and large-screen televisions such as high-definition televisions have been increasing.
CRT, liquid crystal display (hereinafter abbreviated as LCD), plasma display panel (Plasma Display P)
In the field of each display such as anel (hereinafter referred to as PDP), a display suitable for this is being developed.

Conventionally, CRTs, which have been widely used as television displays, are excellent in resolution and image quality, but have a large screen of 40 inches or more in that the depth and weight increase with the screen size. Is not suitable. In addition, LCDs have excellent performance such as low power consumption and low driving voltage, but have technical difficulties in producing a large screen and have a limited viewing angle.

On the other hand, a PDP can realize a large screen even with a small depth, and a 40-inch class product has already been developed. PDPs are roughly classified into a direct current type (DC type) and an alternating current type (AC type). At present, the AC type suitable for upsizing is mainly used. It is also suitable for high-definition screen display.

A conventional PDP generally has a configuration as shown in FIG. In FIG. 7, a band-shaped first display electrode group 19a and a band-shaped second display electrode group 19b are formed on a front substrate 11, and the display electrode groups 19a and 19b are made of a dielectric glass layer made of lead glass or the like. The surface of the dielectric glass layer 17 is covered with a protective layer 18 made of a MgO vapor-deposited film or the like.

On the back substrate 12, a band-like data electrode group 1 is provided.
4 and an insulator layer 13 made of lead glass or the like that covers the surface, and a partition 15 is provided thereon. The front substrate 11 and the rear substrate 12 are combined so that respective electrode groups are orthogonal to each other. The partition 15 is adhered to the rear substrate 12 and is in contact with the front substrate 11. Normally, the front substrate 11 and the rear substrate 12 face each other and are sealed by the partition walls 15 at intervals of about 100 to 200 microns.

The display electrode groups 19a, 19 on the front substrate 11
After forming wall charges by the initializing discharge on the respective dielectric surfaces of the data electrode group 14 on the rear substrate 12 and the data electrode group 14b,
By selectively applying a binary data voltage of zero and a certain value between the first display electrode group 19a and the data electrode group 14, the charge generated by the gas discharge at the intersection of the selected electrodes is reduced. After a writing operation of accumulating on the dielectric glass insulating film 17 and accumulating a latent image of a pixel for one screen by scanning the first display electrode group 19a, the first display electrode group on the front substrate 11 is formed. By the sustain discharge operation of applying an AC pulse voltage between the first display electrode group 19a and the second display electrode group 19b,
An image is displayed when the discharge cells selected in the writing operation emit light simultaneously.

Since the discharge occurs in the space separated by the front substrate 11, the rear substrate 12, and the partition 15, the light emission does not diffuse. That is, the partition 15 has the purpose of defining the distance between the front substrate 11 and the rear substrate 12 and the purpose of performing high-resolution display.

Further, when performing color display, the phosphor 16 is applied to the periphery of the discharge space which is blocked by the partition. Since the phosphor is formed by converting ultraviolet light generated by the discharge into visible light, three primary colors of red (R), green (G), and blue (B) are used, and the emission intensity of each is reduced. By appropriate adjustment, color display becomes possible.

As the discharge gas, in the case of a single color display, a mixed gas mainly composed of neon, which emits light in the visible region at the time of discharge, and in the case of a color display, the emission of light during the discharge is in an ultraviolet region. A mixed gas centered on xenon is selected. The gas pressure assumes the use of PDP under atmospheric pressure,
Usually, the pressure inside the substrate is reduced to 2
It is set in a range from about 00 Torr to about 500 Torr. FIG. 8 shows an electrode matrix diagram of a conventional PDP.

FIG. 9 shows a block diagram of a conventional drive circuit. In FIG. 9, the first display electrode driving circuit includes a scan circuit for performing line-sequential scanning and a sustain discharge circuit.
The second display electrode drive circuit includes a sustain discharge circuit. The data electrode drive circuit includes a serial-parallel conversion circuit for input signals and an output driver circuit. Since the scan circuit and the data electrode drive circuit have a very large number of drive electrodes, a high voltage CMOS IC or the like is usually used. Also, the number of these ICs has increased, which has been a factor in increasing the cost of PDPs.

Next, a conventional PDP driving method will be described with reference to FIG. In FIG. 10, first, electrode group 1
9b initialization pulse is applied to the ₁ through 19b _N, initializing a wall charge in the discharge cells of the panel. Next, the first display electrode group 1
A scanning pulse is applied to the first electrode 19a ₁ of the electrode 9a and a line 14 ₁ corresponding to a discharge cell for displaying the data electrode group 14.
A write pulse is simultaneously applied to .about.14 _M to perform a write discharge to accumulate wall charges on the surface of the dielectric layer.

[0013] Next, zero and 80V the second scan pulse to the line electrodes 19a ₂ of the electrode group 19a, the line 14 ₁ to 14 _M corresponding to the discharge cells for displaying data electrode groups 14
A write pulse of approximately two values is simultaneously applied to perform a write discharge, thereby accumulating wall charges on the surface of the dielectric layer.
Subsequently, similarly, a latent image for one screen is written by sequentially accumulating wall charges corresponding to cells to be displayed by continuous scanning on the surface of the dielectric layer.

Next, in order to perform sustain discharge, the data electrode group 14 is grounded, and the first electrode group 19a and the second electrode group 19
In the cell in which wall charges are accumulated on the surface of the dielectric layer by alternately applying the sustain pulse to b, a discharge occurs when the potential difference on the dielectric surface exceeds the discharge starting voltage, and the sustain pulse is applied. During this period, the main discharge of the display cell selected by the write pulse is maintained. At this time, gradation can be expressed by weighting the number of sustain pulses applied during the sustain period.

Thereafter, a weak discharge is generated by applying an erase pulse having a small width, and the wall charges disappear, so that an erase operation is performed.

As described above, in the conventional PDP driving method,
Image display is performed by a series of driving methods including an initialization period, a writing period, a sustaining period, and an erasing period.

[0017]

However, in the above-mentioned conventional driving method, the write pulse voltage applied during the write period is limited by the withstand voltage of the output driver IC of the data electrode drive circuit, and the write pulse voltage is sufficiently high. There is a problem that stable data writing is not performed on a panel having a high discharge starting voltage, and image quality is deteriorated such as flickering or non-lighting of an image.

In particular, in driving a high-definition panel, it is necessary to end the discharge within a short write pulse time, and for that purpose, the data electrode drive voltage is higher than in the case of VGA screen display. was there.

As a method for solving this problem, an initializing discharge is performed at a high voltage during the initializing period, and a wall voltage having a high absolute value is formed on the dielectric surface on the first display electrode group and the data electrode group. However, there is a problem that the light emission intensity due to the high-voltage reset discharge increases, the black level increases, and the contrast decreases.

As another method for solving the above-mentioned problem, it is conceivable to use an IC having a high withstand voltage as the output driver IC. However, such a driver IC generally increases the cost of a large driving circuit. There was a problem that.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a high-quality and low-cost PDP by stabilizing discharge during a writing period.

[0022]

In order to achieve the above object, the present invention comprises a plurality of opposed first and second display electrodes covered by a dielectric between a pair of parallel substrates; A data electrode disposed so as to be orthogonal to one display electrode, and a discharge space is formed by at least one partition provided between and in contact with at least one of the two substrates. In a method of driving a plasma display panel in which a writing pulse voltage is applied to a discharge cell that is filled and selected between a first display electrode and a data electrode to write data and form a latent image, data is written during a data writing period. A method is used in which a constant bias voltage pulse is applied to the electrodes, and a data pulse is superimposed on the pulse to form a latent image.

It is desirable that the voltage difference between the data pulses for selecting display or non-display be equal to or larger than the voltage difference between the completely selected discharge voltage of the data electrode voltage of the plasma display panel and the completely unselected discharge voltage.

According to another aspect of the present invention, there is provided a display device comprising: a plurality of opposed first and second display electrodes covered by a dielectric between a pair of parallel substrates; And a data electrode disposed so as to be orthogonal to
A discharge space is formed between at least one substrate and at least one partition provided in contact with the substrate, and the discharge space is filled with a discharge gas and is selected between the first display electrode and the data electrode. A first display electrode drive circuit, a second display electrode drive circuit, and a data electrode drive circuit, in a plasma display panel drive circuit for applying a write pulse voltage to a discharge cell and writing data to form a latent image. The data electrode driving circuit has a configuration including a data selection driving circuit for outputting a binary data voltage and a bias voltage pulse applying circuit for applying a constant bias voltage pulse during a data writing period.

Further, as a preferred embodiment, a ground line of the data selection drive circuit is connected to an output terminal of the bias voltage pulse application circuit, a signal input line of the data selection drive circuit is electrically insulated, and There is a configuration including an insulating signal transmitting unit that transmits an input pulse signal to the signal input line.

In a preferred embodiment of the present invention, the insulated signal is transmitted by a photocoupler composed of a combination of a light emitting element and a light receiving element which are electrically insulated from each other. In another preferred embodiment, the insulation signal transmission unit is constituted by an electrically insulated pulse transformer. Alternatively, it is preferable that the insulation signal transmission unit is constituted by a capacitor.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a PDP panel used in the present invention is basically the same as that of a conventional PDP panel. Less than,
An embodiment of the present invention will be described with reference to FIGS.

(Embodiment 1) FIG. 1 is a time chart showing a driving method according to Embodiment 1 of the present invention. FIG.
The difference from the conventional driving method is that the writing pulse applied during the writing period is a binary pulse voltage of zero or a constant voltage in the conventional driving method, whereas the writing pulse of the present invention is A constant bias voltage pulse superimposed on the write data pulse is used and applied to the data electrode to selectively discharge a discharge cell selected by the first display electrode and form a latent image. Therefore, the write pulse takes three values.

The data electrode potential changes up and down in accordance with a write data pulse voltage corresponding to display and non-display data, and these values are superimposed on the write pulse more than the data electrode potential during the initialization period. The potential (including the sign) is increased by the amount of the applied bias pulse voltage.
Thus, the wall voltage of the first display electrode and the data electrode accumulated during the initialization period can be used in the writing period while maintaining the same value as in the conventional driving method. It is effective for conversion.

If a bias voltage having a constant amplitude is applied during the entire driving period, the wall voltage accumulated between the data electrode and the first display electrode during the initialization period becomes lower by the amount of the bias voltage. So it is not a valid method. This is the gist of the present invention.

In addition, since the write pulse potential can be raised by the bias pulse voltage, a data electrode potential higher by the bias pulse voltage can be applied even with the same data pulse voltage.
For the display selection data, the selective discharge of the cell can be reliably performed, and the image quality can be improved without deteriorating the contrast during the initialization period.

Similarly, for the non-display selection data, the data electrode potential increases by the amount of the bias pulse voltage. However, the accumulated wall voltage is maintained as it is, but in the subsequent sustain discharge, the wall voltage has a polarity opposite to that of the voltage applied to the first display electrode. The state is realized.

The present inventors have arrived at the present invention by measuring and examining the wall voltage in detail in the data writing state of the plasma display panel. This will be described below in detail with reference to the drawings.

FIG. 2 shows an example of the wall voltage formed on the first display electrode when the data write voltage is used as a parameter. Cell structure is 140μm trio pitch, 420μm
The cell pitch and the rib height are 100 μm. The initialization voltage applied to the first display electrode was about 400 V, the scanning voltage applied to the second display electrode was 70 V, and the width of the scanning pulse and the writing pulse was 1.5 μs.

The threshold voltage Vdmax (in this case,
(Vdmax = approximately 100 V), display selection discharge occurs,
It has been found that the main discharge between the first and second display electrodes is completely completed within the first electrode scanning pulse period. It is considered that the reason why the wall voltage gradually rises above the threshold voltage value is an increase in the wall voltage due to the discharge between the data electrode and the first display electrode accompanying the increase in the data voltage. Further, at a data voltage equal to or lower than the voltage Vdmin (Vdmin = about 40 V in this case), no wall voltage change occurs and no discharge occurs.

With a voltage between the two, a discharge delay occurs when a pulse voltage is applied, and the discharge does not end within the pulse application time. Therefore, the formed wall charges are partially erased by the after-glow discharge after the pulse application. It is considered to be a phenomenon that occurs for a reason. The higher the voltage applied to the data electrode, the shorter the discharge delay time and the easier the data writing is, and the more complete the data writing becomes. Needless to say, this curve depends on the initialization pulse voltage and the voltage applied to the second display electrode.

As described above, in the data electrode potential shown in FIG.
By setting the voltage between dmax and Vdmin, the complete selective discharge and the complete non-selective discharge are possible. That is, it is preferable that the write data pulse voltage be set to a value equal to or more than (Vdmax-Vdmin). The bias pulse voltage is Vdm
It is preferable to set a value of in or less. In the example of FIG.
The bias pulse voltage may be set to a voltage of about 40V.

With such a configuration, a driver IC of a data electrode driving circuit capable of driving a voltage output of Vdmax (100 V or more) is conventionally required, and a high V
When driving a PDP exhibiting a dmax value, the driver IC becomes expensive, leading to an increase in cost. In the present invention, a driver IC that can drive a relatively low voltage (Vdmax-Vdmin) or more (about 60 V or more in this example) can be used, and cost can be reduced.

In FIGS. 1 and 2, voltage waveforms based on the ground potential are shown for the sake of simplicity, but the present invention is not limited to this and each electrode is made of a dielectric material. Since it is covered and insulated, it goes without saying that the reference potential may be other than zero and the polarity may be different from that shown. It is needless to say that the present invention is not limited to this as long as the sequence of the relative potential difference between the electrode potentials is the same.

(Embodiment 2) FIG. 3 is a block diagram of a driving circuit of a plasma display panel according to Embodiment 2 of the present invention. The difference from the conventional drive circuit is that the data electrode drive circuit is configured to output a binary data voltage, whereas in the present embodiment, the data electrode drive circuit is configured to output a binary data voltage. And a bias voltage pulse applying circuit 32 for applying a constant bias voltage pulse during a data writing period.
This is a point composed of The data electrode drive voltage is the sum of the output of the data electrode selection drive circuit 31 and the output of the bias voltage pulse application circuit 32.

As shown in FIG. 3, a specific configuration for achieving such a configuration is to connect the ground electrode of the data electrode selection drive circuit 31 and its drive power supply 33 to the output terminal of the bias voltage pulse application circuit 32. It is preferable that the entire structure is floated. With this configuration, there is an advantage that the number of bias voltage pulse application circuits 32 can be reduced.
At the same time, the signal to be input to the data electrode selection drive circuit 31 is electrically insulated and transmitted through the insulation signal transmission unit 34.

In the driving circuit of the plasma display panel having such a configuration, the voltage difference between the data pulses for selecting the display and the non-display depends on the completely selected discharge voltage of the data electrode voltage of the plasma display panel and the completely unselected voltage. It is preferable that the difference be equal to or more than the voltage difference from the discharge voltage.

Here, as an example of a specific embodiment of the insulating signal transmitting section 34, as shown in FIG. 4, a combination of a light emitting element and a light receiving element which are electrically insulated and opposed to each other is used. It may be constituted by a photocoupler.

Another specific embodiment of the insulated signal transmitting section is, as shown in FIG. 5, constituted by an electrically insulated pulse transformer.

Further, as another specific example of the embodiment of the insulating signal transmitting section, as shown in FIG. 6, it is preferable that the insulating signal transmitting section is constituted by a capacitor.

By adopting such a configuration, the driving method disclosed in (Embodiment 1) becomes possible, and high-speed writing can be performed while suppressing deterioration of contrast, and complete writing without flicker can be performed. This enables a high-quality screen display.

A driver IC in which the output voltage range of the data selection drive circuit is lower than the maximum voltage required by the data electrode for writing by a bias voltage pulse.
Therefore, the cost of the drive circuit can be reduced. In particular, it is effective for driving a high-definition plasma display panel having a high discharge starting voltage.

[0048]

As described above, according to the present invention, a discharge delay at the time of writing discharge is improved, a writing defect is remarkably improved, and a contrast deterioration is suppressed.
Can be realized at low cost.

[Brief description of the drawings]

FIG. 1 is a timing chart showing a driving method of a plasma display panel according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the dependence of a wall voltage Vw of a first display electrode on Vdata in the first embodiment of the present invention.

FIG. 3 is a block diagram of a driving circuit of the plasma display panel according to the second embodiment of the present invention;

FIG. 4 is a diagram illustrating an example of a specific embodiment in which an insulating signal transmission unit according to a second embodiment of the present invention is configured by a photocoupler;

FIG. 5 is a diagram showing an example of a specific embodiment in which an insulating signal transmission unit according to the second embodiment of the present invention is configured by a pulse transformer;

FIG. 6 is a diagram showing an example of a specific embodiment in which an insulating signal transmission unit according to a second embodiment of the present invention is configured by a capacitor.

FIG. 7 is a configuration diagram of a conventional plasma display panel.

FIG. 8 is an electrode matrix diagram of a conventional plasma display panel.

FIG. 9 is a block diagram of a driving circuit of a conventional plasma display panel.

FIG. 10 is a timing chart of a conventional plasma display panel driving method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Front substrate 12 Back substrate 13 Insulator layer 14 Data electrode group 15 Partition wall 16 Phosphor 17 Dielectric glass layer 18 Protective film 19a Electrode group 19b Electrode group 31 Data electrode selection drive circuit 32 Bias voltage pulse application circuit 33 Drive power supply 34 Insulation Signal transmission section

Claims (8)

[Claims] A plurality of opposing first and second display electrodes covered with a dielectric material between a pair of parallel substrates; and a data electrode disposed orthogonal to the first display electrodes. A discharge space is formed between the two substrates by a partition wall provided in contact with at least one of the substrates, the discharge space is filled with a discharge gas, and the first display electrode and the data are formed. A method for driving a plasma display panel in which a write pulse voltage is applied to discharge cells selected between electrodes to write data and form a latent image, wherein a constant bias voltage pulse is applied to a data electrode during the data write period. And driving a plasma display panel by superimposing a data pulse thereon to form a latent image. 2. The method according to claim 1, wherein a voltage difference between data pulses for selecting display or non-display is equal to or greater than a voltage difference between a completely selected discharge voltage and a completely unselected discharge voltage of data electrode voltages of the plasma display panel. The method for driving a plasma display panel according to claim 1. 3. A plurality of opposing first and second display electrodes covered with a dielectric between a pair of parallel substrates, and a data electrode disposed so as to be orthogonal to the first display electrode. A discharge space is formed between the two substrates by a partition wall provided in contact with at least one of the substrates, the discharge space is filled with a discharge gas, and the first display electrode and the data are formed. A driving circuit for driving a first display electrode, wherein the driving circuit drives a first display electrode, the driving circuit applying a write pulse voltage to a discharge cell selected between the electrodes to write data and form a latent image; And a data electrode drive circuit, the data electrode drive circuit outputting a binary data voltage, and a constant bias voltage during a data write period. Driving circuit of a plasma display panel, comprising the bias voltage pulse applying circuit for applying a pulse. 4. A ground line of a data selection drive circuit is connected to an output terminal of a bias voltage pulse application circuit, a signal input line of the data selection drive circuit is electrically insulated, and an input to the signal input line is provided. 4. The driving circuit for a plasma display panel according to claim 3, further comprising an insulating signal transmitting unit that transmits a pulse signal. 5. The apparatus according to claim 3, wherein the insulated signal transmitting section is constituted by a photocoupler comprising a combination of a light emitting element and a light receiving element which are electrically insulated from each other.
Or the driving circuit of the plasma display panel according to 4. 6. The driving circuit for a plasma display panel according to claim 3, wherein the insulation signal transmission unit is constituted by an electrically insulated pulse transformer. 7. The driving circuit for a plasma display panel according to claim 3, wherein the insulation signal transmission section is constituted by a capacitor. 8. A plurality of opposing first and second display electrodes covered with a dielectric and a data electrode arranged to intersect with the first display electrode between a pair of substrates. A discharge cell group is formed by a partition wall between the two substrates, the discharge cell group is filled with a discharge gas, and a write pulse voltage is applied to a discharge cell selected between the first display electrode and the data electrode. An image display device for writing data by applying the data and forming a latent image, wherein
An image display device characterized by using a value.