JP2000215814A - Discharge type display panel and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To omit a dielectric layer on the front side and to realize manufacture at a low cost and high light transmittance by exposing first electrodes on the back glass side, second electrodes on the address discharging front glass side and third electrodes nearby like DC electrodes, or covering them with a conductive cathode material with high secondary electron emissivity or a thin insulating cathode material, and applying sustain pulses between them in turn. SOLUTION: Stripe-like first electrodes 1 on the back glass side are covered with a dielectric layer 2 on the back glass side to form AC type electrodes, lattice-like barrier ribs 3 are formed on the AC type electrodes, and a phosphor is applied. No dielectric layer is provided on the surfaces of stripe-like second electrodes 5 on the front glass side and third electrodes 6 parallel to the second electrodes 5, and they are covered with LaB6 having high secondary electron emissivity or MgO of an insulator having a thin film layer forming no wall charge by conductivity as a protective layer. Both glasses are sealed, evacuated and filled with discharge gas to form a discharge panel, fine sustain pulses are applied between the second and third electrodes 5, 6 at a high frequency, and a sustain discharge is continued in a sufficient plasma residual state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of a discharge type display device.

[0002]

2. Description of the Related Art FIG. 6 and FIG.
The conventional technique will be briefly described with reference to FIG. FIG. 7 shows a three-electrode surface discharge type ACPDP, and FIG. 8 shows a two-electrode opposed discharge type ACPDP. FIG. 9 shows a pulse memory type DCPDP. First, a conventional technique will be described with reference to FIG. The back glass substrate has a first electrode 1 whose surface is covered with a dielectric layer 2.
Partition walls 3 are arranged on both sides of the partition wall to form a discharge space, and a phosphor 4 is applied on the partition wall surface and the dielectric layer 2 covering the first electrode. The shape of the partition wall is generally a stripe shape, but may be a lattice shape.

On the front glass side, a second electrode 5 extending so as to face and intersect the first electrode 1 on the back side and a third electrode 6 extending in parallel with the second electrode 5 are formed. . The second electrode 5 intersects the first electrode 1 to form an XY matrix. However, since the third electrode does not need to have an address function, the lines are usually used by commonly connecting the lines. The surfaces of the second and third electrodes, which are a pair of discharge electrodes, so to speak, are first covered with a front-side dielectric layer 7, and the surface of the dielectric layer has a high secondary electron emissivity and a high ion impact. It is covered with a protective layer 8 of a material which is also strong, for example, magnesium oxide, strontium oxide, or the like.
Usually, this protective layer 8 is formed by a thin film method, for example, 0.5 μm
Since the film itself is so thin that it cannot be a dielectric layer for wall charge accumulation, which is the original ACDPP operation, a dielectric film obtained by printing and firing low melting glass having a thickness of about 10 to 20 μm is usually used. The structure is such that the electrode is covered with the layer 7 and the protective layer 8 is further covered thereon.

As a method of driving the panel having the conventional structure, for example, a pulse as shown in FIG. 4 is applied to each electrode. First, an image signal C corresponding to an image is applied to the first electrode 1 in FIG. 6 during the address period in FIG. The scanning signal A is applied to the second electrode 5 extending in the horizontal direction. Since these electrodes intersect in an XY matrix, a wall charge is formed on the dielectric layer of each electrode at the pixel where the discharge has occurred, and on the phosphor on the dielectric layer on the back side at this time. For example, with the pulse having the polarity shown in FIG. 4, a positive wall charge is formed on the first electrode 1 side, and a negative wall charge is formed on the second electrode 5 side. Naturally, such a wall charge is not formed in an unselected pixel in which the address discharge has not occurred. Now, the scanning signal A
Address discharge is sequentially performed, and the address of one screen is completed. When the screen is viewed, a distribution of pixels having no wall charges and no pixels is formed.

In this state, the next sustain period starts,
When a sustain pulse as shown in FIG. 4 is applied, discharge occurs between the second electrode 5 and the third electrode 6 only in a pixel in which a so-called wall voltage due to wall charge is generated. When the discharge occurs, the polarity of the wall charges of the second electrode 5 is reversed and becomes positive, and the negative wall charges are formed on the third electrode 6. After that, the sustain pulse is applied to the second electrode 5 and the third electrode.
By alternately applying the voltage to the electrodes 6, the discharge is maintained while the wall charges are formed in reverse.

A characteristic feature of such a conventional panel structure and driving method is that the discharge is stopped each time the sustain discharge is performed, that is, charged particles such as ions and electrons are already diffused or recombined in the discharge space. It disappears and stops with only a small amount of metastable atoms present, and the polarity of the wall charge of the dielectric layer on each electrode is reversed. This can be achieved when the width of the sustain pulse is about 2.0 microseconds or more. If the width of the sustain pulse is 1.0 microsecond or less, the discharge is not continued because the wall charges are not sufficiently formed.

Therefore, in the conventional PDP, the condition is that the wall charge is continuously formed during the sustain period. Therefore, the dielectric layer 7 is indispensable, and the width of the sustain pulse is at least about two. On the order of 0.0 microseconds has been required.

The structure of such a conventional AC type PDP and the concept of the driving method are basically the same in the conventional two-electrode opposed discharge panel shown in FIG. However, in the structure of FIG. 8, since the sustain discharge is performed between the first electrode 1 and the second electrode 5 of the opposing electrodes, the fluorescent substance 4 on the first electrode on the back side is charged with ions. Shocked and deteriorates quickly. Therefore, conventionally, a window 9 for opening an electrode is provided in a part of the phosphor 4. Since the structure of this panel does not include the three-electrode type third electrode 6 shown in FIG. 7, the driving pulse is also as shown in FIG. 5, but the operation is basically the same, so that its detailed description will be omitted. Omitted.

In each of the above AC type PDPs, an electrode is covered with a dielectric layer, and a method of giving a so-called memory function by forming wall charges on the electrode is adopted. On the other hand, the DC type panel shown in FIG. 9 does not have a memory function structurally because neither electrode is covered with a dielectric layer. Although a resistor for preventing overcurrent is inserted on the anode side in FIG. 9, this resistor may be omitted from the viewpoint of basic operation. In order to perform the memory drive, that is, the sustain operation, of this panel, the effect of a decrease in the discharge voltage due to the so-called priming effect due to the metastable atoms remaining in the discharge space abundantly is utilized. However, in order to maintain discharge in a plurality of pixels at the same time, the discharge space immediately after each pixel starts discharging is operated with a relatively high impedance. For this purpose, the pulse is applied with a narrow pulse, for example, a pulse width of about 1.0 microsecond or less. This is called a pulse memory operation in DCPDP. In this case, since the state of the discharge space has a memory function, it is necessary to immediately enter the sustain state after the address discharge.

[0010]

As described above, in a conventional AC-type discharge display device, that is, an ACPDP, first, a so-called reflective P-type display panel having a phosphor layer on the back side in a panel structure.
In the case of DP, the electrode on the front side was an AC type electrode which was always covered with a dielectric layer as a main discharge electrode. For this reason, a material having high transparency is required for the dielectric layer, and there are many steps such as printing, drying and firing of the dielectric layer, and there is a problem such as distortion of the glass due to the firing step. Further, in the conventional driving method, since it is a necessary condition that the formation of the wall charges is completely performed even during the sustain period, there is a limit in increasing the frequency of the sustain, and thus there is a limit in luminance. In the conventional DC discharge display device, that is, DCPDP, the electrodes are not structurally formed to have a memory function, so that there is a limitation in driving.

[0011]

In order to solve the above-mentioned problems, the present invention combines an AC type electrode having a dielectric layer and a DC type electrode having no dielectric layer in the electrode structure to continue the conventional sustain discharge by wall charge. Instead, a narrow sustain pulse is applied at a high frequency, and sustain discharge is continued by maintaining a state in which the plasma sufficiently remains in the discharge space. A PDP having a simple structure in which a dielectric layer is omitted is proposed.

[0012]

[Embodiment 1] First, regarding claim 1 of the present invention,
Embodiment 1 will be described with reference to a part of a developed perspective view of the display panel shown in FIG. A first electrode 1 and a dielectric layer 2 covering the first electrode 1 are formed on the rear glass, and a partition 3 is formed on the dielectric layer 2 to define each pixel and as a spacer to the front glass. In FIG. 1, the partition walls 3 are shown in a lattice shape, but may be in a stripe shape depending on the panel and driving conditions. Phosphors 4 that contribute to light emission using ultraviolet rays generated by the discharge are applied on the wall surfaces of the partition walls 3 and on the dielectric layer 2. First
The electrode 1 is formed by printing and baking a conductive ink by a method such as screen printing, and the dielectric layer 2 can be easily formed by printing and baking a low-melting glass paste so as to cover the first electrode 1. The partition walls 3 can be formed by overprinting of low-melting glass, but excavation by sandblasting or the like has also been put to practical use. Phosphors can also be formed by, for example, a printing method, and red, green, and blue phosphors are selectively applied to each pixel.

On the front glass side, parallel striped electrodes are formed as second and third electrodes 5 and 6. This can be formed by printing a silver paste or the like, for example, or by pattern-forming a transparent conductive film such as indium tin oxide or a deposited film such as chrome. The characteristic feature of the panel of the present invention shown in FIG. 1 is that the dielectric layer 7 is not provided on the front glass side as is clear as compared with FIG. With respect to the protective layer 8, the operation alone of the AC type PDP was originally insufficient for forming wall charges alone, and was not formed separately from the dielectric layer 7 in the conventional structure. In the display device of the present invention, the wall charge is not formed during the sustain discharge period unlike the related art, so that the dielectric layer 7 as shown in FIG. 7 is unnecessary. Has a role of secondary electron emission as a cathode material. Therefore, also in the present invention, the surface of the second electrode 5 is directly covered with a conductive cathode material having a high secondary electron emissivity, such as lanthanum hexaboride, without covering the surface of the second electrode 5 with the dielectric layer 7, or Similarly, by forming a cathode material having a high secondary electron emissivity and having a small thickness although it is an insulator, a DC current flows in a discharge state and a so-called A
A cathode material that does not form wall charges, such as a C-type PDP, may be coated with a thin film layer of magnesium oxide, strontium oxide, barium oxide, yttrium oxide, or the like. Even if these are usually insulators, they can operate as DC electrodes in any case by making them as thin as, for example, about 5000 Å as described above.

[0014]

[Embodiment 2] Next, with regard to claim 2 of the present invention,
Embodiment 2 will be described with reference to a part of an exploded perspective view of the display panel shown in FIG. Since the back glass side is exactly the same as that shown in FIG. 1 of the first embodiment,
Here, redundant description is omitted. However, in the case of this structure, the sustain discharge is performed between the first electrode 1 and the second electrode 5, but due to the operation of the narrow pulse described later, the ion impact on the phosphor 4 is small. Therefore, the electrode window 9 as shown in the conventional two-electrode opposed discharge panel of FIG. 8 is unnecessary. However, since a cathode material for secondary electron emission is effective, a cathode material similar to the protective layer 8 of the first embodiment may be applied on the phosphor 4 in some cases. The shape of the partition wall 3 is not limited to a lattice shape as in the first embodiment, but may be a stripe shape.

A second electrode 5 is formed on the front glass side. This is also exactly the same as that shown in FIG. 1 which is the first embodiment, except that the third electrode 6 is omitted, and thus redundant description is omitted here.

[0016]

[Embodiment 3] Next, regarding claim 3 of the present invention,
The third embodiment will be described with reference to a part of a developed perspective view of the display panel shown in FIG. The back glass side is exactly the same as that shown in FIG. 1 of the first embodiment and FIG. 2 of the second embodiment, and a redundant description is omitted here. In the case of this structure, the basic operation is the same as that of FIG. 2, but it is characterized in that the second electrode 5 is formed of a metal wire. When it is necessary to match the expansion coefficient with glass, an alloy of iron nickel chrome, titanium, or the like is used as the metal material. Besides, tungsten, aluminum and the like may be used. In addition, the surface of the wire may be covered with a thin film of a cathode material, for example, magnesium oxide, strontium oxide, barium oxide, yttrium oxide, or the like, or of course, with a conductive cathode material such as lanthanum hexaboride. It may be coated. These can be easily formed by a method such as an electrodeposition method.

[0017]

Sustain pulse applied to the embodiment of the present invention In the structure shown in FIG. 1 of the first embodiment of the present invention, the sustain discharge is performed between the second electrode 5 and the third electrode 6 which are DC electrodes. In order to prevent an excessive current from flowing, the sustain pulse width must be as narrow as about 1.0 microsecond or less. 2 and 3 of the second embodiment.
In FIG. 3, in order to prevent the phosphor 4 covering the first electrode 1 on the back side from being sputtered due to ion bombardment, the sustain pulse width must also be as narrow as about 1.0 microsecond or less. . Further, in order to realize the above-described structures of the present invention best, a driving method combined with the above-mentioned structures is that a plasma is always present in the discharge space during the sustain period so that the structure has conductivity. A driving method that is placed in an inclined state is effective.
For this purpose, the pulse width and the interval between the sustain pulses shown in FIG. 6 are set as follows. That is, the pulse widths 10 and 12 of the sustain pulses A and B shown in FIG.
And pulse intervals 11 and 13 between A and B and between B and A, and all of these times are set to about 1.0 microsecond or less. In this way, plasma and metastable atoms are always present in the discharge space while being reproduced. Although the pulse waveform itself shown in FIG. 6 has no novelty, a new discharge display device is realized by setting the pulse timing as described above and applying the pulse timing to the PDPs of the first, second and third embodiments. I do.

[0018]

When driving the PDP having the structure shown in FIG. 1 according to the first embodiment of the present invention, the timing of the pulse to be applied is basically the same in the PDP having the structure shown in FIG. There is a necessary condition in the sustain pulse. That is, an AC pulse is applied between both electrodes at a very short period, that is, at a high frequency, during which the plasma, that is, ions, electrons, and metastable atoms do not disappear in the discharge space during the sustain period. This differs depending on the dimensions in the panel, the gas pressure, the gas composition, the electrode voltage and the like, but usually the pulse width and the interval between each pulse may be set to about 1.0 microsecond or less. That is, the frequency of each pulse alternately applied between both electrodes is 250
kHz or higher is a condition. The condition of the sustain pulse is exactly the same when applied to the second and third embodiments, and the operation is the same. This will be described in more detail below.

First, consider applying the pulse shown in FIG. 4 to the PDP having the structure shown in FIG. Here, the pulse C is applied to the first electrode 1, the pulse A is applied to the second electrode 5, and the pulse B is applied to the third electrode 6, respectively. Exciting a discharge at the intersection of the XY matrix corresponding to the image during the address period is the same as in a conventional PDP. However, in this case, the wall charges are formed only on the AC electrode on the back side, that is, only on the phosphor 4. The address period ends, and the operation proceeds to the sustain period. The first discharge is selectively generated between the first electrode 1 and the second electrode 5 based on the presence or absence of the wall charges. In such a case, the discharge is immediately applied to the second electrode 5 and the third electrode 6.
In the case of the structure of FIG. 2, the second electrode and the first
Continue between electrodes. At this time, the pulse width and the pulse interval of the sustain are extremely short, about 1.0 μsec, so that there is still enough plasma in the discharge space and the discharge space is still conductive. Therefore, the wall charges formed on the dielectric layer 2, that is, the phosphor 4, are lost by the address discharge, and wall charges of the opposite polarity are formed such that the sustain pulse is inverted before the wall charges of the opposite polarity are formed again. no time. However, the conductivity of the discharge space between the electrodes is reduced only in the immediate vicinity of the two electrodes, and there is a large difference in the discharge voltage between the non-selected pixels. Therefore, the sustain discharge is selectively continued here. Done. That is, in the high frequency sustain discharge, the sustain discharge can be selectively sustained according to the image even without the wall charge, so that the front-side dielectric layer 7 in the conventional structure becomes unnecessary.

In general, when a discharge is performed between a pair of DC electrodes, unless a load resistance is inserted in series, the impedance between the electrodes becomes extremely low after the start of the discharge, so that an excessive current flows and the electrodes are damaged. However, if the pulse width, that is, the voltage application time is reduced to, for example, about 1.0 microsecond or less, the cathode has not yet fallen in the gas space, so that the internal impedance is low and an excessive current does not flow. That is, it is known that the current can be controlled by the pulse width, and that the discharge during this period has high luminous efficiency.

There is a concern that charged particles and metastable atoms in the plasma diffuse around the discharged electrode and reduce the discharge voltage of the non-selected pixels in the vicinity, thereby lowering the selection effect and deteriorating the operating conditions. For this reason, the grid-like partition walls can prevent the diffusion of plasma and widen the operating conditions. However, depending on the pixel spacing and the composition of the discharge gas, the stripe-shaped partition walls can also have a sufficiently wide operating range.

[0022]

First, in the structure according to the first, second and third aspects of the present invention, since there is no dielectric layer on the front side as in a normal PDP, the number of manufacturing steps is small and the cost is low. Brightness is high because it is high. In the structure according to the third aspect, the use of a metal wire for the electrode eliminates the step of firing the electrode, thereby reducing the number of steps. In addition, since the problem of deformation of the glass substrate is avoided, the step is simplified, and the assembly accuracy is reduced. Will also be higher. Further, by driving the panel having the structure according to the first, second and third aspects with a narrow and high frequency AC type sustain pulse, a display device with high luminance and high luminous efficiency is realized. The discharge voltage is reduced due to the residual plasma effect compared with the case of driving, and the ion impact on the electrode is reduced, resulting in a longer life.

[0023]

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of Embodiment 2 of the present invention.

FIG. 3 is an exploded perspective view of Embodiment 3 of the present invention.

FIG. 4 is a timing diagram of a sustain pulse for driving a PDP having a structure according to the present invention;

FIG. 5 is an exploded perspective view of a conventional three-electrode surface discharge type ACPDP.

FIG. 6 is an exploded perspective view of a conventional two-electrode opposed discharge type ACPDP.

FIG. 7 is an exploded perspective view of a conventional DC pulse memory PDP.

[0023]

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st electrode 2 back side dielectric layer 3 partition 4 fluorescent substance 5 2nd electrode 6 3rd electrode 7 front side dielectric layer 8 protective layer 9 electrode window

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[Procedure amendment]

[Submission date] April 30, 1999 (1999.4.3)
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a developed perspective view of a first embodiment.

FIG. 2 is an exploded perspective view of the second embodiment.

FIG. 3 is an exploded perspective view of the third embodiment.

FIG. 4 is a pulse timing chart of each electrode for driving the PDP according to the first embodiment.

FIG. 5 is a pulse timing chart of each electrode for driving the PDP according to the second embodiment.

FIG. 6 shows a sustain pulse waveform and timing applied to the embodiment.

FIG. 7 is an exploded perspective view of a conventional three-electrode surface discharge type ACPDP.

FIG. 8 is an exploded perspective view of a conventional two-electrode opposed discharge type ACPDP.

FIG. 9 is an exploded perspective view of a conventional pulse memory type PDP.

[Description of Signs] 1 First electrode 2 Back side dielectric layer 3 Partition wall 4 Phosphor 5 Second electrode 6 Third electrode 7 Front side dielectric layer 8 Protective layer 9 Electrode window

Claims (5)

[Claims] In a structure of a discharge type display panel, that is, a so-called plasma display panel, first, an electrode configuration thereof is provided. On a back glass side, a stripe-shaped first electrode constituting one electrode of an XY matrix which performs an address function is provided. It is formed as a so-called AC type electrode whose surface is covered with a dielectric layer. On the same back glass plate, a grid-like shape surrounding the first electrode or a stripe-like shape sandwiching the first electrode is formed. A phosphor is applied on the partition wall surface and the dielectric layer of the first electrode, and a stripe constituting the other electrode of the XY matrix for performing an address discharge is formed on the front glass side. And a second electrode, which does not perform address discharge but is arranged in parallel with or close to the second electrode, which is a shape-shaped electrode. It has a third electrode for performing in-discharge, and both of these electrodes are so-called DC electrodes, that is, a structure in which the surface is directly exposed to the discharge space without coating the surface with a dielectric layer, or the surface is secondary. Either a structure coated with a conductive cathode material with a high electron emissivity, or a structure coated with a cathode material that is an insulator but has a property that is not equivalent to conductivity because it is formed of an extremely thin layer In this structure, both of these electrodes are formed as so-called DC type discharge electrodes, and these front glass and rear glass are arranged as if the electrodes face each other via a partition wall, and then sealed with a glass frit. A discharge panel completed through processes such as vacuum evacuation and discharge gas filling; a DC-type second electrode disposed on the front glass side;
A discharge type display panel structure wherein AC type sustain discharge is performed by alternately applying a sustain pulse between the C type third electrodes. 2. The structure of a discharge type display panel, that is, a so-called plasma display panel, in which the electrode structure is a stripe-shaped electrode constituting one electrode of an XY matrix having an address function and a sustain function on the back glass side. The first electrode is formed as a so-called AC type electrode whose surface is covered with a dielectric layer, and is formed on the same back glass plate as a grid or a sandwich formed so as to surround the first electrode. And a phosphor is applied on the partition wall surface and the dielectric layer of the first electrode, and on the front glass side, an address is provided facing the first electrode. It has a second electrode which is a striped electrode constituting the other electrode of the XY matrix for performing the discharge and the sustain discharge, and this second electrode is a so-called DC type. An electrode, that is, a structure in which the surface is directly exposed to the discharge space without being covered with a dielectric layer, or a structure in which the surface is covered with a conductive cathode material having a high secondary electron emissivity, or an insulator, for example, The second electrode is formed as a DC-type discharge electrode in any structure, such as a structure coated with a cathode material that exhibits a property that does not actually differ from the conductivity because it is formed as a thin layer. After the electrodes are arranged as if they face each other via a partition wall, they are sealed with a glass frit and completed through processes such as evacuation and discharge gas filling. Said AC-type first electrode,
A structure of a discharge type display panel characterized in that an AC type sustain discharge is performed by alternately applying a sustain pulse between the DC type second electrodes arranged on the front side. 3. In a structure of a discharge type display panel, that is, a so-called plasma display panel, first, an electrode configuration thereof is a stripe-shaped electrode constituting one electrode of an XY matrix having an address function and a sustain function on a back glass side. The first electrode is formed as a so-called AC type electrode whose surface is covered with a dielectric layer, and is formed on the same back glass plate as a grid or a sandwich formed so as to surround the first electrode. A phosphor is applied on the partition wall surface and the dielectric layer of the first electrode, and on the front glass side, facing the first electrode. It has a second electrode which is a striped electrode constituting the other electrode of the XY matrix for performing the address discharge and the sustain discharge, and the second electrode is a thin metal wire. This wire electrode is a so-called DC type electrode, that is, a structure in which the surface is directly exposed to the discharge space without being covered with a dielectric layer, or the surface is covered with a conductive cathode material having a high secondary electron emissivity. Any structure, such as a structure that is covered with a cathode material that is an insulator but formed of an extremely thin layer and that does not actually have the same conductivity as the second structure, can be used as the second structure.
Are formed as DC type discharge electrodes. After these front glass and rear glass are arranged as if the electrodes face each other via a partition, they are sealed with a glass frit, evacuated and filled with discharge gas. The AC type is applied by alternately applying a sustain pulse between the DC type second electrode disposed on the front glass side and the AC type first electrode disposed on the rear side. A structure of a discharge type display panel characterized by performing a sustain discharge. 4. A discharge panel according to claim 1, having a pair of second and third parallel discharge electrodes both of which are DC discharge electrodes on the front side, and a sustain pulse applied to both electrodes. A discharge display device for applying
As a condition of the sustain pulse, the pulse width and the interval between each pulse are set within the time when the plasma does not disappear in the discharge space, for example, the pulse width and the pulse interval are all about 1.0 microsecond or less. A discharge display device that is driven by a sustain pulse under the above conditions. 5. A second electrode which is a DC-type discharge electrode on the front side and an AC on the rear side according to claim 2 and 3.
And a discharge panel in which a first electrode, which is a type of electrode, intersects and a sustain pulse is applied to both electrodes. The conditions of the sustain pulse include a pulse width and a pulse width between each pulse. The discharge is required to be performed within a time period in which the plasma does not disappear in the discharge space, for example, the pulse width and the pulse interval are all about 1.0 microsecond or less, and the panel having the above structure is driven by the sustain pulse under the above conditions. Display device.