JP2000305516A - Ac plasma display panel and its driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC plasma display panel having a high luminous efficiency without enlarging the length between electrodes, and without increasing largely an application voltage for discharge sustainment. SOLUTION: A first electrode X and a second electrode Y are installed in parallel on either of two parallel substrates 3, 4, and a belt-like partition wall 10 parallel to the first and second electrodes X, Y is installed on the other substrate 4, and a third electrode A is installed on the bottom part of the partition wall 10. By giving a wall charge selectively to the partition wall 10 beforehand, a voltage applied on a discharge space between the second and third electrodes Y, A when an initial sustained discharge is generated, becomes a voltage obtained by adding a voltage obtained by a sustained voltage pulse to a voltage obtained by the wall charge, and the added voltage exceeds a firing potential between the second and third electrodes Y, A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a structure of an AC type plasma display panel capable of obtaining high luminous efficiency and a driving method thereof.

[0002]

2. Description of the Related Art The configuration of a conventional AC type plasma display panel is shown in FIG. FIG. 6B is a cross-sectional view taken along a line DD ′ shown in FIG. 6A. As shown in FIG. 6, a conventional AC plasma display panel (hereinafter referred to as a panel) 15 has a first
The glass substrate 13 and the second glass substrate 4 are arranged to face each other. The first glass substrate 13 is a transparent glass substrate. On the first glass substrate 13, a pair of strip-shaped scan electrodes 7 and sustain electrodes 8 covered with a dielectric layer 5 and a protective layer 6 are provided. Are arranged in parallel with each other. The scanning electrode 7 and the sustaining electrode 8 are respectively composed of transparent electrodes 7a, 8a and metal busbars 7b, 8b for increasing conductivity.
It is composed of

[0003] On the second glass substrate 4, strip-shaped data electrodes 9 are arranged in parallel to each other at right angles to the scanning electrodes 7 and the sustaining electrodes 8. These data electrodes 9 are isolated from each other and discharged. A strip-shaped partition 10 for forming the space 2 is provided between the data electrodes 9. In addition, a phosphor 11 is formed from above the data electrode 9 to the side surface of the partition wall 10. Further, helium, neon,
A mixed gas of at least one kind of rare gas and xenon is sealed in argon. The panel 15 is configured to view an image display from the first glass substrate 13 side, which is the display surface side, and is exposed to ultraviolet light generated by a discharge between the scan electrode 7 and the sustain electrode 8 in the discharge space 2. The phosphor 11 is excited, and visible light from the phosphor 11 is used for display light emission.

Next, a method for displaying image data on the conventional panel 15 will be described. As a conventional method of driving a panel, one field period is divided into a plurality of subfields having a weight of a light emitting period based on a binary system,
A gradation display is performed by a combination of subfields to emit light. Each subfield includes an initialization period, an address period, and a sustain period. In order to display image data, different signal waveforms are applied to the electrodes during the initialization period, the address period, and the sustain period. In the initialization period, for example, a positive pulse voltage is applied to the sustain electrodes 8 and the data electrodes 9 to all the scan electrodes 7 to accumulate wall charges on the protective layer 6 and the phosphor 11. In the address period, while sequentially applying a negative pulse to the scan electrode 7, the data electrode 9 is applied only when there is display data.
Is applied with a positive data pulse. At this time, a discharge between the scan electrode 7 and the sustain electrode 8 is induced by a discharge between the data electrode 9 and the scan electrode 7, and a wall charge is formed on the protective layer 6 according to the presence or absence of a data pulse. In the subsequent sustain period, a voltage sufficient to maintain discharge is applied between scan electrode 7 and sustain electrode 8 for a certain period. This allows
Discharge plasma is generated at the intersection of the scan electrode and the sustain electrode,
The phosphor 11 is excited to emit light for a certain period. No discharge or light emission occurs in the discharge space where no data pulse was applied during the address period.

In such a conventional panel, the scanning electrodes 7
And the gap 12 between the sustain electrodes 8 is formed near a value at which a minimum discharge voltage determined by Paschen's law is obtained.
This is for reducing the external sustain voltage Vsus applied between the scan electrode 7 and the sustain electrode 8 during the sustain period. That is, when the discharge start voltage between the sustain electrode 8 and the scan electrode 7 is Vfss, and the wall voltage between them is Vwss, there is a relationship of Vfss <Vsus + Vwss (1). By designing the panel so that Vfss is minimized, the display discharge can be maintained at a lower applied voltage Vsus. The lower the external sustain voltage Vsus is, the easier the circuit design is, and the loss due to reactive power can be reduced. At present, it is known that the luminous efficiency of the panel being manufactured is highest when the total pressure of the sealed gas is about 50 to 60 kPa and the partial pressure of the xenon gas is 5 to 10%.
At this time, when the gap 12 is 80 to 100 μm, Vsus becomes extremely small, and Vsus = 180 to 200 V is obtained.

[0006]

The above-mentioned conventional panel has a drawback that the light emission efficiency is extremely low as compared with a display device such as a CRT. For example, in the above-described panel having the gap 12 of 80 to 100 μm, the luminous efficiency is about 1 lm / W, which is about one fifth of the CRT. In general, it is known that the luminous efficiency of discharge increases as the distance between the electrodes causing discharge increases, but when the distance between the operating electrode 7 and the sustaining electrode 8 is increased, the discharge starting voltage Vfss also sharply follows the Paschen curve. And driving becomes difficult. In view of the above, the present invention provides an AC-type plasma display panel with high light emission efficiency without greatly increasing an applied voltage for sustaining discharge, with respect to a panel having an increased electrode length.

[0007]

According to the AC type plasma display panel of the present invention, two substrates are arranged to face each other with a strip-shaped partition therebetween, and a first substrate is provided on one of the substrates in a direction orthogonal to the partition. A first electrode and a second electrode covered with a dielectric layer are formed, and a third electrode covered with a second dielectric layer is formed on the other substrate in parallel with the partition wall; One electrode constitutes one discharge cell, a pulse voltage is applied between the first electrode and the third electrode during the address period to selectively form wall charges on the dielectric layer, and during the sustain period, (1) A sustain voltage pulse is alternately applied to the second electrode, and a voltage applied to the discharge space between the second and third electrodes when the first sustain discharge occurs is caused by the second voltage with the first dielectric layer serving as a cathode. , The discharge starting voltage between the third electrodes or higher. With this configuration, it is possible to increase the inter-electrode length related to the sustain discharge without greatly increasing the discharge sustain voltage, and to obtain an AC-type plasma display panel with significantly improved luminous efficiency.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. FIG.
It is sectional drawing cut | disconnected along line EE 'shown to (a). As shown in FIG. 1, A of the first embodiment of the present invention
C-type plasma display panel (hereinafter called panel)
In 1, a first glass substrate 3 and a second glass substrate 4 are arranged to face each other with a discharge space 2 interposed therebetween. The first glass substrate 3 is a transparent glass substrate, and the first glass substrate 3 is covered with a dielectric layer 5 and a protective layer 6,
An electrode group consisting of a pair of strip-shaped first and second electrodes X and Y is arranged in parallel with each other. The protective layer 6 is made of a material having a high secondary electron emission coefficient such as MgO.

On the second glass substrate 4, a third group of band-shaped third electrodes A are arranged in parallel with each other at right angles to the first electrode X and the second electrode Y. A strip-shaped partition wall 10 for isolating and forming a discharge space is provided between the third electrodes A. Further, the phosphor 11 is formed from the third electrode A to the side surface of the partition wall 10. Further, the discharge space 2 is filled with a mixed gas of at least one rare gas and xenon among helium, neon, and argon. The panel 1 is configured to view an image display from the first glass substrate 3 side, which is the display surface side, and excites the phosphor 11 by ultraviolet rays generated by the discharge in the discharge space 2. Is used for display light emission.

In the panel of this embodiment, the first electrode X
The gap between the first electrode X and the second electrode Y (hereinafter referred to as the main discharge gap) is dss.
When a gap between them (called a sub-discharge gap) is dsa, dss> dsa. Next, a method for displaying image data on the panel 1 of the present embodiment will be described. As a method of driving the panel 1 of the present embodiment, one field period is divided into a plurality of subfields having a weight of a light emission period based on a binary system, and gradation display is performed by a combination of subfields to emit light. Each subfield includes an initialization period, an address period, and a sustain period. To display image data, the initialization period,
Different signal waveforms are applied to the electrodes during the address period and the sustain period. In the initialization period, for example, a positive pulse voltage is applied to all the first electrodes X with respect to the second electrode Y and the third electrode A, and the dielectric layer 6 and the phosphor 1
1 accumulate wall charges.

In the address period, scanning is performed by sequentially applying a negative pulse to the first electrode X. If there is display data, a positive data pulse is applied to the third electrode A while scanning the first electrode X. At this time, the first electrode X is discharged by the discharge between the third electrode A and the first electrode X.
A discharge is induced between the electrode X and the second electrode Y, and wall charges are formed on the protective layer 6 according to the presence or absence of a data pulse. In the subsequent sustain period, a voltage sufficient to maintain the discharge is applied between the first electrode X and the second electrode Y for a certain period. Thus, during the sustain period, the discharge plasma is generated in the main discharge gap between the first electrode X and the second electrode Y by the preliminary discharge generated between the first electrode X or the second electrode Y and the third electrode A. Is generated, and the phosphor 11 is excited and emits light for a certain period. No discharge or light emission occurs in the discharge space where no data pulse was applied during the address period.

Next, the relationship between the applied voltage waveform and the wall voltage in the address period and the sustain period will be described in detail with reference to the driving waveforms shown in FIGS. In FIG. 2, (a)
Is the voltage Vx (t) applied to the first electrode X, (b) is the voltage Vy (t) applied to the second electrode Y, and (c) is the voltage Va (t) applied to the third electrode A FIG. In FIG.
(A) is the applied voltage of X viewed from Y (Vx (t) -Vy (t)),
(B) is the applied voltage of X viewed from A (Vx (t) -Va (t)),
(C) is the applied voltage of Y viewed from A (Vy (t) -Va (t)).
Are shown by solid lines, and the waveform diagrams of the wall voltage in each case are shown by dotted lines. The polarity of the wall voltage is chosen so that the difference from the applied voltage indicates the voltage applied between each discharge gap.

Here, the firing voltage between the electrodes is defined as follows. Vfss: a discharge starting voltage between the first electrode X and the second electrode Y. Vfsa: a discharge starting voltage between the first electrode X (or the second electrode Y) and the third electrode A using the first electrode X (or the second electrode Y) as a cathode. Vfas: a discharge starting voltage between the first electrode X (or the second electrode Y) and the third electrode A using the third electrode A as a cathode. Vfssa: first electrode X (or second electrode Y) and third electrode A
Between the first electrode X and the second electrode X when a discharge exists between
A firing voltage between the electrode Y. Vfss is the same as the discharge starting voltage between the scanning electrode 7 and the sustaining electrode 8 in the conventional panel, but in the present embodiment, the gap between the first electrode X and the second electrode Y is enlarged, This value is larger than the discharge starting voltage between the scan electrode 7 and the sustain electrode 8 in the panel. Vfsa and Vfas
Vfsa is different from Vfsa in that the cathode is MgO having a high secondary electron emission coefficient, whereas Vfsa is Vfsa.
As has a relation of Vfsa≪Vfas because as uses a phosphor whose secondary electron emission coefficient is considerably lower than that of MgO as a cathode. If a discharge has previously occurred between the first electrode X or the second electrode Y and the third electrode A, a large amount of initial charges exist in the discharge space where the discharge has occurred,
The firing voltage between the first electrode X and the second electrode Y decreases, and V
fssa≪Vfss.

FIG. 4 is a table showing design parameters of the panel of this embodiment. In this panel, each discharge starting voltage was Vfss = 700 V Vfsa = 280 V Vfas = 380 V Vfssa = 450 V.

Based on the above preparation, the driving waveforms of FIGS. 2 and 3 will be described. First, in the address period, a pulse of about -100 V is applied to the first electrode X and a +70 V pulse is applied to the third electrode A to cause a discharge (address discharge) to cause a wall on the MgO and the phosphor layer. Accumulate charge. At this time, the second electrode Y is at a positive bias potential of +250 V, and discharge occurs between the second electrode and the first electrode or the third electrode due to the address discharge. As a result, the wall charges are distributed over the entire surface of the protective layer 6 and the phosphor 11, so that the wall voltage has a value that cancels the voltage applied from the outside.
For this reason, FIG. 3 illustrates that the wall voltage matches the applied voltage when the address discharge occurs. When entering the sustain period, first, the second electrode Y is lowered to a negative bias potential of -300 V. At the same time, the amplitude Vsus = 300 V is applied to the first electrode X.
Is applied. Subsequently, a sustain pulse having an amplitude of 300 V having a phase 180 ° different from that of the first electrode X is applied to the second electrode Y, and the pulse is applied alternately during the sustain period.

Looking at the voltage applied to the gap between the electrodes at the time when the sustain period starts (time t1), the wall voltage is applied, so that about 850 is applied between X and Y.
FIG. 3 shows that a voltage of about 370 V is applied between V and X-A and a voltage of about 480 V is applied between Y and A. Also, a voltage is applied between X-A with a polarity using the phosphor as a cathode, and between YA with a polarity using MgO as a cathode. Therefore,
From the relationship of Vfsa <480V, Vfas> 370V, it is understood that discharge starts between YA. Also, a voltage higher than the discharge starting voltage is applied between X and Y. However, when the first sustain discharge pulse is applied, most of the space charges formed by the address discharge have disappeared, so the X-Y discharge start voltage rises to the above value, 700 V or more. I have. As a result, the discharge may not be started by the first sustain pulse.
No. 485 has been proposed. This prior art discloses a method of increasing the voltage of the first pulse of the sustain period or increasing the pulse width. In this embodiment, as described above, first, a discharge is caused between YA and a discharge between X and Y is induced using this as a trigger, so that a sustain pulse having a constant amplitude and pulse width is applied from the beginning. Thus, the sustain discharge can be reliably started.

When the second pulse of the sustain period is applied (time t2), about 600 V is applied between X and Y, and about 300 V is applied between X and A and YA. At this time, the voltage applied between X-A has a polarity using MgO as a cathode, and the voltage applied between YA has a polarity using a phosphor as a cathode, so that Vfsa <300 V, Vfas> From the relationship of 300 V, discharge starts first between XA. XY
Vfssa <600 V <Vfss From equation (2), discharge starts with discharge between X and A as a trigger. By repeating the above operation, a panel having a large main discharge gap dss can be displayed with a relatively low sustain voltage of 300 V.

From FIG. 3 and equation (2), it can be seen that V in the sustain period.
Since the sum of sus and the wall charge Vwss is added to the main discharge gap, it can be seen that Vfss and Vfssa may appear to be effectively 1/2 from the outside. Next, the applied voltage in the sustain period when driving the panel of the present embodiment is shown.
This will be described with reference to FIG. In FIG. 5, the horizontal axis represents the main discharge gap ds.
s and the vertical axis is voltage. Vfss and Vfs
The sa is halved from the above consideration so that it can be compared with the externally applied voltage. The discharge starting voltage Vfss is a so-called Paschen curve having a minimum value at a relatively small dss. Vfssa is a curve having almost the same shape as Vfss, but its value is lower than Vfss. On the other hand, Vfsa does not depend on dss and is a substantially horizontal straight line. Note that Vfss = Vfsa is not always satisfied when dss = dsa.
This is because the electric field distribution differs between the main discharge gap and the sub discharge gap. In the example shown in FIG. 5, dss =
When dsa, Vfss> Vfsa.

The panel of this embodiment operates in the region B where the applied voltage Vsus is Vfsa <Vsus and 1 / 2.Vfssa <Vsus <1 / 2.Vfss during the sustain period. As a result, even when the main discharge gap dss is set to be larger than the conventional one such as dss> dsa, the sustain discharge can be induced by the discharge generated in the sub discharge gap, so that the luminous efficiency is greatly increased. Further, the discharge can be maintained at a relatively low externally applied voltage despite the increase in the main discharge gap dss. Further, when the main discharge gap dss at which Vfssa / 2 = Vfsa is d0, by setting dss ≦ d0, the minimum value of the external sustaining voltage Vsus is substantially equal to the maximum sustaining voltage (fVfsa) of the conventional panel. Therefore, the luminous efficiency can be improved without imposing a large load on the driving circuit. On the other hand, in the conventional panel,
For example, dsa = 130 to 150 μm and dss = 80 to 100 μm, and the relationship between the electrodes is designed to be dss <dsa. In the sustain period when such a conventional panel is driven, an external sustain voltage Vsus that satisfies Vwsa <Vfsa Equation (3) is applied in addition to the condition of Equation (1). Therefore, in the sustain period, Vwss ≒ Vsus, Vwsa ≒ Vsus
Then, in the conventional panel, Expressions (1) and (3)
5 (see FIG. 5), and no discharge occurred in the address discharge space.

In the panel whose design values are shown in FIG.
m / W luminous efficiency, which is 2
The luminous efficiency has improved almost twice. As described above, in the present embodiment, since the main discharge gap can be enlarged, it is possible to obtain an AC-type plasma display panel with high luminous efficiency and suppressed increase in driving voltage.

[0021]

As described above, the present invention provides an AC-type plasma display panel in which the main discharge gap is made wider than the sub-discharge gap, thereby improving the luminous efficiency without greatly increasing the sustaining voltage. It is. In this embodiment, the address period and the sustain period are separated.
Although the so-called address-sustain separation type drive has been described as an example,
It goes without saying that the same effect can be obtained in an AC type plasma display using another addressing method.

[Brief description of the drawings]

FIG. 1 is a sectional view of an AC type plasma display panel according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an applied voltage waveform of the AC type plasma display panel of the present invention.

FIG. 3 is a diagram showing a wall voltage waveform of the AC type plasma display panel of the present invention.

FIG. 4 is a view showing an example of design values of an AC type plasma display panel according to the first embodiment of the present invention.

FIG. 5 is a diagram for explaining an operating voltage in a sustain period of the AC plasma display panel of the present invention.

FIG. 6 is a cross-sectional view of a conventional AC plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC type plasma display panel 2 Discharge space 3 1st glass substrate 4 2nd glass substrate 5 Dielectric layer 6 Protective layer X 1st electrode Y 2nd electrode A 3rd electrode 10 Partition 11 Phosphor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 11/00 H01J 11/00 K 11/02 11/02 B (72) Inventor Koji Ito Kadoma, Osaka 1006 Oaza Kadoma Matsushita Electric Industrial Co., Ltd. GG12 HH02 HH04 JJ04 JJ05 JJ06

Claims (9)

[Claims] 1. Two substrates are arranged opposite to each other with a strip-shaped partition therebetween, and a first electrode and a second electrode covered with a first dielectric layer in a direction orthogonal to the partition on one of the substrates. An electrode is formed, and a second electrode is formed on the other substrate in parallel with the partition wall.
Forming a discharge cell with the three electrodes, and applying a pulse voltage between the first electrode and the third electrode during an address period to form a dielectric cell. Forming wall charges selectively on the layer,
A sustain voltage pulse is alternately applied to the first and second electrodes, and a voltage applied to a discharge space between the second and third electrodes when the first sustain discharge is generated is a voltage applied to the first dielectric layer using the first dielectric layer as a cathode. 2. A which is higher than the discharge starting voltage between the third electrodes
A method for driving a C-type plasma display panel. 2. An amplitude of the sustain voltage pulse is larger than a discharge starting voltage between a first or second electrode and a third electrode using the first dielectric layer as a cathode, and the first electrode or the second electrode is
First and second triggered by discharge between the electrode and the third electrode
2. The method of driving an AC-type plasma display panel according to claim 1, wherein the discharge start voltage between the electrodes is greater than 1/2. 3. The method of driving an AC plasma display panel according to claim 1, wherein the amplitude of the sustain voltage pulse is smaller than 1/2 of a firing voltage between the first and second electrodes. 4. A first electrode and a second substrate covered with a first dielectric layer in a direction perpendicular to the partition on one of the substrates, wherein two substrates are opposed to each other with a strip-shaped partition therebetween. An electrode is formed, and a second electrode is formed on the other substrate in parallel with the partition wall.
Forming a discharge cell with the three electrodes, and applying a pulse voltage between the first electrode and the third electrode during an address period to form a dielectric cell. Forming wall charges selectively on the layer,
A sustain voltage pulse is alternately applied to the first and second electrodes, and the voltage applied to the discharge space between the second and third electrodes when the first sustain discharge occurs is determined by the voltage obtained by the sustain voltage pulse and the wall charge. And the resulting voltage is the sum of the voltages,
A method of driving an AC plasma display panel, wherein the added voltage is equal to or higher than a discharge starting voltage between the second and third electrodes using the first dielectric layer as a cathode. 5. A method according to claim 1, wherein two substrates are opposed to each other with a strip-shaped partition therebetween, and a first electrode and a second electrode which are covered with a first dielectric layer in a direction orthogonal to the partition on one of the substrates. An electrode is formed, and a second electrode is formed on the other substrate in parallel with the partition wall.
Forming a discharge cell with the three electrodes, comprising an address pulse generating means and a sustain pulse generating means, wherein the address pulse generating means is provided during an address period. A pulse voltage is applied between the first electrode and the third electrode to selectively form wall charges on the dielectric layer, and the sustain pulse generating means applies a sustain voltage to the first and second electrodes during a sustain period. The voltage applied to the discharge space between the second and third electrodes when pulses are alternately applied and the first sustain discharge occurs is caused by the discharge between the second and third electrodes using the first dielectric layer as a cathode. An AC-type plasma display panel characterized by having a starting voltage or higher. 6. An amplitude of the sustain voltage pulse is larger than a discharge starting voltage between a first or second electrode and a third electrode using the first dielectric layer as a cathode, and the first electrode or the second electrode.
First and second triggered by discharge between the electrode and the third electrode
6. The AC type plasma display panel according to claim 5, wherein the voltage is higher than 1/2 of a discharge starting voltage between the electrodes. 7. The AC type plasma display panel according to claim 5, wherein the amplitude of the sustain voltage pulse is smaller than 1/2 of a discharge starting voltage between the first and second electrodes. 8. The method according to claim 1, wherein the gap between the first and second electrodes is the first,
6. The AC type plasma display panel according to claim 5, wherein the width is wider than a gap between the third electrodes or between the second and third electrodes. 9. Two substrates are arranged opposite to each other with a strip-shaped partition therebetween, and a first electrode and a second electrode which are covered with a first dielectric layer in a direction orthogonal to the partition on one of the substrates. An electrode is formed, and a second electrode is formed on the other substrate in parallel with the partition wall.
Forming a discharge cell with the three electrodes, comprising an address pulse generating means and a sustain pulse generating means, wherein the address pulse generating means is provided during an address period. A pulse voltage is applied between the first electrode and the third electrode to selectively form wall charges on the dielectric layer, and the sustain pulse generating means applies a sustain voltage to the first and second electrodes during a sustain period. The voltage applied to the discharge space between the second and third electrodes when pulses are alternately applied and the first sustain discharge is caused is the sum of the voltage obtained by the sustain voltage pulse and the voltage obtained by the wall charge. An AC-type plasma display panel, wherein the voltage is equal to or higher than a discharge starting voltage between the second and third electrodes using the first dielectric layer as a cathode.