JP2003059411A - Plasma display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma display device capable of a high contrast display. SOLUTION: In a panel part, auxiliary electrodes 20X and 20Y are arranged inside a protective layer 19 so as to be opposed to respective sustaining electrodes 17X and 17Y. The auxiliary electrodes 20X and 20Y are respectively connected to a pulse generating circuit, and when the connection is cut off after impressing voltage in a reset period, electric charge is accumulated on a surface of the protective layer 19 according to electric potential of an electric charge holding part CH. These electric charges are electric charge functionally equivalent to wall electric charge, and sustaining discharge is easily started thereby without performing preliminary discharge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display device which performs display by utilizing AC plasma discharge.

[0002]

2. Description of the Related Art In recent years, in response to the trend toward thinner and larger screens, various flat panel displays (FPDs) have been developed.
play) has been developed and put into practical use. A plasma display panel (PDP) is also one of such display devices, and has been commercialized as a wall-mounted television having a large screen of 40 inches or more. Plasma displays are roughly classified into AC type and DC type, but the AC type, which is superior in luminous efficiency and life, is becoming the mainstream.

FIG. 19 shows a schematic structure of a panel portion in a conventional AC type plasma display device. The panel portion 100 has a structure in which a rear glass substrate 101 and a front glass substrate 102 on the display surface side are arranged to face each other, and is hermetically sealed at the peripheral edge portion and filled with a discharge gas. On the rear glass substrate 101, a plurality of address electrodes 103 arranged in parallel with each other are provided. The address electrode 103 is arranged so as to be orthogonal to the sustain electrode 107, and the intersection of the two corresponds to the pixel. Address electrode 10
3 is provided with a dielectric layer 104, and further above that,
Partition wall 10 for partitioning a space for each address electrode 103
5 are provided in stripes. Phosphors 106 are periodically provided between the partition walls 105.

On the other hand, on the front glass substrate 102, sustain electrodes 107 (107X, 107) for performing sustain discharge are provided.
Y) are provided in pairs. A discharge gap between the sustain electrodes 107X and the sustain electrodes 107Y serves as a discharge gap during surface discharge, and is generally about 100 μm. Bus electrodes 110X and 110Y for reducing electric resistance are integrally provided on sustain electrodes 107X and 107Y, respectively. A dielectric layer 108 and a protective layer 109 are sequentially provided on the sustain electrodes 107.

This plasma display device operates as follows, for example. First, all the sustain electrodes 107X and 107Y
When a voltage is applied to the protective layer and a preliminary discharge is performed between them, the protective layer 1
Electric charges (wall charges) are formed on 09. Next, the sustain electrodes 107X and the address electrodes 1 corresponding to the pixels that do not emit light.
When address discharge is performed by applying a voltage to 03, wall charges are erased. Next, the sustain electrodes 107X, 1
When an AC voltage is applied between 07Y, the voltage between the sustain electrodes 107X and 107Y reaches the discharge start voltage due to the superposition of the voltage due to the wall charge and the pulse voltage at the pixel position where the wall charge remains, and discharge occurs. . This discharge is a high frequency discharge, and at the same time, electric charges are accumulated, so that discharge is continuously generated and the discharge state is maintained (sustain discharge). The ultraviolet rays emitted by the discharge gas are emitted to the phosphor 106 by this discharge and emit light to display a pixel.

20A to 20C show an example of a driving method of a plasma display device based on the above principle. FIG. 6B shows voltage waveforms input to each of the m sustain electrodes 107Y. Since the voltage waveforms input to the sustain electrodes 107X paired with these are all the same, this is ) Shows one portion. The display screen of one field in general image display is composed of weighted subfields, and gradation display is performed by control of the subfields. Each subfield is divided into a reset period, an address period following the reset period, and a display period. In the reset period, preliminary discharge is performed for all pixels over the entire screen to uniformly form wall charges. In the address period, a pixel is selected by selectively generating an address discharge in a pixel that does not emit light to erase the wall charge and leaving the wall charge only in a pixel position where light emission is desired. In the next display period, for all pixels (all sustain electrodes 107X, 107Y
AC voltage is applied. At this time, the sustain discharge occurs only in the pixel in which the wall charge is formed, the light emission is continued during the display period, and the pixel is turned on. On the other hand, the pixels in which the wall charges are not formed in the address period do not discharge nor emit light, and thus are displayed in black. In this way, a predetermined pattern of light emission occurs within one subfield.

The driving method described above is called the selective erasing method. In contrast to this, the electric charge is erased by the preliminary discharge, and the wall charge is selectively applied to the pixel position to be emitted by the address discharge. There is a selective writing method that accumulates. In any case, there is no difference in that the preliminary discharge must be generated in the reset period.

[0008]

Recently, although the flat type plasma display device has almost reached the practical range, a sufficient contrast has not been obtained yet. One of the causes is the preliminary discharge performed during the reset period. In the normal image display method, the preliminary discharge is always performed once for each subfield as described above. The discharge light generated at that time is not the light emission for image display, but since the light emission intensity is not a level that can be ignored for screen display, the luminance of the entire screen shifts to the higher side by the contribution of the light emission of the preliminary discharge. I will end up. Therefore, even when displaying a black region, it is difficult to display a sufficiently black region, and therefore the contrast is significantly reduced.

The present invention has been made in view of such problems, and an object thereof is to provide a plasma display device capable of high-contrast display.

[0010]

In a plasma display device according to the present invention, an auxiliary electrode formed in a region between a sustain electrode pair and an address electrode and having a charge holding portion, and a voltage is applied to this auxiliary electrode. And a voltage applying section for

In the plasma display device according to the present invention, when a voltage is applied to the auxiliary electrode, a capacitive potential is generated in the charge holding portion, and the charge is accumulated in each pixel region accordingly.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment] FIG. 1 is a configuration diagram showing a configuration of a panel portion of a plasma display device according to a first embodiment of the present invention, and FIG. 2 is shown in FIG. It is sectional drawing in the II line of a panel part. The panel portion is configured by combining a rear glass substrate 11 and a front glass substrate 12. Of these, the back glass substrate 11
Is a plate of high strain point glass or soda lime glass. Address electrodes 13A made of a metal thin film such as Al (aluminum) are arranged in parallel on the rear glass substrate 11, and Si, for example, is further provided thereon.
A dielectric layer 14 of O ₂ (silicon dioxide) is provided. Further, on the dielectric layer 14, partition walls 15 for partitioning the discharge space into each address electrode 13A are provided. The partition 15 has, for example, a trapezoidal cross section,
It is mainly formed of low melting point glass. A phosphor 16 is provided between the partition walls 15 on the side surface of the partition wall 15 and on the exposed surface of the dielectric layer 14.

The front glass substrate 12 located on the display side is
It is necessary to have high transparency, and for example, high strain point glass or soda lime glass is used similarly to the rear glass substrate 11. A plurality of sets of sustain electrodes 17 (17X, 17Y) are provided on the front glass substrate 12 such that the extension direction of the sustain electrodes 17 and the extension direction of the address electrodes 13A are orthogonal to each other. A matrix having intersections as pixels is formed. These sustain electrodes 17 are transparent electrodes made of, for example, ITO (Indium-Tin Oxide).

In this case, the pair of sustain electrodes 17 is used.
The gap between X and 17Y (discharge gap) is less than 50 μm, preferably 20 μm or less. This is because the sustain discharge by the negative glow discharge is normally performed by the cathode glow discharge in this plasma display device. To use a negative glow, a discharge gap of about 100 μm is required, whereas a cathode glow has a discharge gap of 50 μm.
Discharge is possible even if less than. By narrowing the discharge gap in this way, the size of the pixel is reduced, and high-definition display can be realized. Further, the cathode glow discharge, compared to the negative glow discharge, to increase the discharge efficiency with the same input power, or
There is an advantage that the same or higher luminance can be obtained with a lower discharge sustaining voltage.

On the other hand, the distance between the sustain electrode 17 and the address electrode 13A is set to, for example, about 100 μm, and the address discharge is performed by negative glow discharge. The distance between the pair of adjacent sustain electrodes 17 is, for example, 20 μm or more in order to prevent crosstalk between pixels. Further, as shown in FIG. 2, each of the sustain electrodes 17X and 17Y is provided with a bus electrode 21 made of a metal such as Al for reducing electric resistance.

A dielectric layer 18 made of, for example, SiO ₂ is provided on the sustain electrode 17, and M, for example, is further provided thereon.
A protective layer 19 made of gO (magnesium oxide) is provided. Here, the auxiliary electrode 2 is provided inside the protective layer 19 so as to face the sustain electrode 17 (17X, 17Y).
0 (20X, 20Y) is arranged. However, the auxiliary electrode 20 may be provided inside the dielectric layer 18.

As described above, in the panel portion 10, in the region between the sustain electrodes 17X and 17Y and the address electrode 13A,
Two auxiliary electrodes 20X and 20Y are provided. Each of the auxiliary electrodes 20X and 20Y has a conductive portion CE that is electrically conductive and a charge holding portion CH formed in each pixel region, and the charge holding portions CH of each form an equivalent capacitance. Therefore, when voltages having different polarities are applied to the auxiliary electrodes 20X and 20Y, charges are accumulated on the facing surface side of the charge holding portion CH (FIG. 2). Such an auxiliary electrode 20 can be arbitrarily provided in a region of the panel unit 10 where charge is desired to be accumulated. However, in order for the electric charge to serve to provide a bias voltage with respect to the discharge start voltage between the predetermined electrodes, it is necessary to be accumulated at least in the discharge path between the electrodes. Here, considering that a bias voltage is applied to the sustain discharge by the sustain electrodes 17X and 17Y, the charge holding portions CH of the auxiliary electrodes 20X and 20Y are arranged so as to accumulate charges in the discharge path of the sustain discharge. .

The charge holding portion CH is one of the auxiliary electrodes 20.
It is responsible for the capacitance and at the same time limits the region in the pixel region where charges are accumulated. That is, the position of the auxiliary electrode 20 described above is substantially the position of the charge holding portion CH. This charge holding portion CH is the auxiliary electrode 2
The auxiliary electrode 20 is formed on at least one side in the width direction of 0.
The electric potential is changed by injecting and attracting electric charge through the conductive portion CE, which is the main body portion, and accordingly, the electric charge is formed and held or erased in each pixel region. Further, in order to enable the holding / erasing of charges for each pixel, it is possible that the charges in the charge holding unit CH may flow out, or may flow into another charge holding unit CH through the conductive unit CE. It has a structure to prevent it. For example, in FIG.
As shown in (A) and (B), a tag-shaped charge holding portion C
You may make it attach H. In this case, the constriction of the charge holding portion CH prevents the movement of charges inside and outside thereof. In this way, by devising the shape of the charge holding portion CH, it is conceivable to increase the electric resistance at the boundary with the conductive portion CE.

Alternatively, the structure of the charge holding portion CH is such that the charge transfer as described above can be ignored within a predetermined period (here, a period from the accumulation of charges to the start of sustain discharge). If For example, the boundary portion with the conductive portion CE is formed of a material having higher resistance,
It is conceivable that the whole is made of a material having a resistance higher than that of the conductive portion CE. Charge Retaining Section C in this Embodiment
H has such a structure and is formed at a position corresponding to each pixel region on one side of the conductive portion CE, as shown in an enlarged view in FIG. Further, FIG. 3D shows the case where the charge holding portion CH is formed on both sides of the conductive portion CE, which has the same material configuration as that of FIG. 3C.

The thicknesses and widths of the charge holding portion CH and the conductive portion CE of the auxiliary electrode 20 are appropriately determined in consideration of the charge capacity and the area for accumulating charges (that is, the area for changing the potential). It is set, and its material can be arbitrarily selected. Since they are provided on the display surface side, they are preferably formed of a highly transparent material, such as ITO, but since they have relatively low conductivity, for example, ITO is used for the charge holding portion CH. It is more preferable that the conductive portion CE is made of a metal material and the auxiliary electrode 20 is provided so as not to affect the light emission during display as much as possible.

Therefore, the auxiliary electrode 20X of the present embodiment,
20Y is set as follows. FIG. 4 shows the arrangement of the auxiliary electrodes 20X and 20Y in the panel section 10,
(A) is a partial cross-sectional view of the front glass substrate 12 side, (B)
[Fig. 3] is a plan view of (A). The conductive portions CE of the auxiliary electrodes 20X and 20Y are made of, for example, the same metal material as the bus electrode 21, and are provided in the same shape at positions facing the bus electrode 21, respectively. In addition, the charge holding portions CH of the auxiliary electrodes 20X and 20Y are made of ITO and are formed between the conductive portions CE of the both and in the region intersecting with the address electrode 13A so as to face the sustain electrodes 17X and 17Y. It is assumed that each pixel area is provided. The charge holding portion C
In H, electric charges are concentrated in a region close to the opposite charge holding unit CH (from inside), and wall charges also tend to be formed inside the charge holding unit CH. By considering such a wall charge formation region first, the arrangement and shape of the conductive portion CE and the charge holding portion CH of the auxiliary electrode 20 can be recursively designed.

The rear glass substrate 11 thus constructed
The front glass substrate 12 and the front glass substrate 12 are opposed to each other with a discharge space therebetween, and are hermetically sealed at the peripheral edge portion with a spacer (not shown). A discharge gas is enclosed in the discharge space, and the discharge space partitioned by the partition walls 15 constitutes individual discharge cells and emits light in pixel units. As the discharge gas, for example, He, Ne,
At least one of rare gases of Ar, Xe, and Kr is used, and a mixed gas of Ne and Xe or a gas composed of only Xe is preferable. It should be noted that the panel unit 1 for performing cathode glow discharge
For 0, the Xe concentration in the Xe mixed gas is 3
It is preferably 0% or more and less than 100%. Further, the discharge gas pressure is set to a pressure capable of stably performing high-luminance and high-efficiency discharge in relation to the mutual distance between the sustain electrodes 17X and 17Y and the address electrode 13A that perform discharge. Specifically, the discharge gas pressure is preferably 5 kPa or more and 50 kPa or less.

FIG. 5 shows a drive circuit of this plasma display device. The drive circuit is pulse generation circuits 31 to 33.
And pulse generation circuits 41 and 42. The pulse generating circuits 31 to 33 are connected to the sustain electrodes 17Y and 17X and the address 13A, respectively, and apply a predetermined AC pulse voltage for discharging. The pulse generation circuits 41 and 42 are connected to the auxiliary electrodes 20X and 20Y via the switches S1 and S2, respectively, and apply a pulse voltage for charge storage. These switches S1 and S2 are, for example, FET (Field Effect Transis).
tor) and other semiconductor elements. In addition,
In the present embodiment, the pulse generation circuits 41 and 42 correspond to the “voltage applying section” of the present invention.

The panel section 10 as described above can be manufactured, for example, as follows.

First, a front glass substrate 12 is prepared, and a transparent electrode material such as ITO is used to form a pattern of, for example, sputtering or screen printing to form a pair of stripe-shaped sustain electrodes 17. Then, along one side edge of these sustain electrodes 17, for example, A
The bus electrode 21 is formed in the same manner as the sustain electrode 17 using a highly conductive metal material such as g, Al, Ni, Cu or Cr. After that, for example, SiO ₂ is CVD (Chemical
Vapor Deposition) method or printing method is used to form the dielectric layer 18.

Next, auxiliary electrodes 20X and 20Y are formed on the dielectric layer 18 in a predetermined shape at positions facing the sustain electrodes 17X and 17Y. That is, in the same manner as the sustain electrode 17 and the bus electrode 21, the charge holding portion CH facing the sustain electrodes 17X and 17Y is patterned using ITO or the like, and then the conductive portion facing the bus electrode 21 is made of a metal material. Form CE. Then, a protective layer 19 made of MgO is formed on the entire surface of the dielectric layer 18 on which the auxiliary electrode 20 is formed, for example, by an electron beam evaporation method.
As a result, the auxiliary electrode 20 is formed so as to be embedded inside the protective layer 19 on the substrate 12 side.

Next, the rear glass substrate 11 is prepared, and a highly conductive metal material such as Ag, Al, Ni, Cu, Cr is formed on the rear glass substrate 11 in a stripe shape by sputtering or screen printing. , The address electrode 13A is formed. Next, for example, SiO _{2 is formed} by a CVD method or a printing method, and the dielectric layer 14 is formed to a predetermined thickness. Next, on the upper surface of the dielectric layer 14, the partition wall 1 is formed in the region between the adjacent address electrodes 13A.
5 is formed into a trapezoidal shape. For example, the partition wall 15 is formed by applying and forming a paste-like low melting point glass by a screen printing method, shaping it into a stripe shape by a sandblasting method, and baking it. At that time, the height of the partition wall 15 is 100 μm or more, for example, about 150 μm. Next, from the side surfaces of the adjacent partition walls 15 to the dielectric layer 14 between them.
Then, the phosphor 16 is formed between the partition walls 15 by, for example, printing or applying / exposing the phosphor slurry.

Next, the rear glass substrate 11 and the front glass substrate 12 are assembled. For example, a seal layer made of low melting point glass is formed on the peripheral portion of the front glass substrate 12 by screen printing. After that, the rear glass substrate 11 and the front glass substrate 12 are attached to each other so that the sustain electrodes 17 and the address electrodes 13A are orthogonal to each other, and baked to cure and cure the seal layer. Furthermore, with respect to the discharge space provided between the two substrates 11 and 12 and partitioned by the partition wall 15,
Exhaust and enclose mixed gas. As described above, the mixed gas is preferably a mixed gas of Ne and Xe or a single gas of Xe. In practice, the electrodes 11A, 1
The end portions of 7, 20 are led out from the main body portion, and the pulse generating circuits 31 to 33, 41 and 42 are used as power feeding terminals.
Are connected.

Next, the operation of this plasma display device will be described with reference to FIGS. 2, 5, 6 and 7. 6A to 6E show a drive sequence (for one subfield) showing a voltage waveform input from the drive circuit to the panel unit 10, and FIGS. 7A to 7D show the panel unit 10. The voltage change of each electrode from the start of the operation to the address discharge is shown.

(Reset period) First, the switches S1 and S
2 is in the on state. First, the pulse generation circuits 41 and 42
As a result, when the predetermined pulse voltages + V _r and -V _r are applied to all the auxiliary electrodes 20X and 20Y, the charge holding portions CH of the respective charge holding portions CH are changed in accordance with the potentials (+ V _r and -V _r ) of the auxiliary electrodes 20. On the surface of the protective layer 19, positive charges are accumulated in the area facing the charge holding portion CH on the auxiliary electrode 20X side, and in the area facing the charge holding portion CH on the auxiliary electrode 20Y side while the charges are accumulated inside. Accumulates negative charges. The applied voltage at this time is, for example, +5 with respect to the auxiliary electrode 20X.
The voltage is 0 V and −100 V with respect to the auxiliary electrode 20Y. Here, the region where the negative charges are accumulated is almost within the discharge path of the address discharge.

When a sufficient amount of charge is accumulated, the switches S1 and S2 are opened (OFF state), and the auxiliary electrodes 20X,
By floating 20Y, the charge in each charge holding portion CH is fixed, and the charge on the surface of the protective layer 19 accumulated in response to this is also continuously held. Therefore,
Even after the switches S1 and S2 are opened, positive and negative potentials (+ V _r , -V _r ) are generated on the surface of the protective layer 19 due to the accumulated charges.
Is maintained. Thus, normally, the sustain electrodes 17X, 1
While the so-called wall charges are formed by discharging between 7Y, here, after applying a voltage to the auxiliary electrodes 20X and 20Y, the auxiliary electrodes 20 and the pulse generating circuits 41 and 42 are applied.
By cutting off the connection with the electric charge, the electric charge is normally accumulated in the region where the wall electric charge is formed. In this way, charges corresponding to the wall charges are accumulated without emitting light during the reset period.

(Address Period) Next, the pulse voltage −V _s from the pulse generating circuits 31 and 33 to the sustain electrode 17Y and the address electrode 13A corresponding to the pixels not to be displayed, respectively.
When V _a is applied, negative glow discharge occurs between the two electrodes.
This is the address discharge, and as the voltages −V _s and V _a , for example, −50 V is applied to the sustain electrode 17Y and +70 V is applied to the address electrode 13A. This leaves the accumulated charge in a perfect state only in the pixel to be displayed. In addition,
At the start of the address discharge, the surface potential of the protective layer 19 is
The voltage applied to the sustain electrodes 17Y to potential -V _r due to charge -
V _s is superimposed - a (V _s + V _r). Therefore, the substantial potential difference between the sustain electrode 17Y and the address electrode 13A is V _s + V _r + V _a (FIG. 7), and the voltages −V _s and V are obtained.
_The value of a can be as low as V _r .

Immediately after this address period, the switches S1,
S2 is turned on, and the auxiliary electrodes 20X and 20Y are connected to the pulse generation circuits 41 and 42 and grounded.
The timing of this connection can be set arbitrarily as long as the next reset period comes before the voltage is applied to the auxiliary electrodes 20X and 20Y.

(Maintenance Period) Next, the pulse generation circuit 31,
32, all the sustain electrodes 17Y and the sustain electrodes 17
An AC drive pulse is applied to X. The drive pulse can be set to 160V to 180V, for example. At this time, only the pair of sustain electrodes 17X and 17Y whose potential difference has reached the discharge start voltage by superposing the voltage (2V _r ) due to the accumulated charges on the drive pulse voltage reaches the discharge gap. (Sustaining discharge) occurs. Thus, only the pixels having the accumulated charge continuously emit light during the period in which the drive pulse is applied.

As described above, in the present embodiment, the auxiliary electrodes 20X and 20Y are provided so that the respective charge holding portions CH face the sustain electrodes 17X and 17Y, and the pulse generating circuit 41 and the auxiliary electrodes 20X and 20Y are provided. Since 42 is connected, the pulse generation circuit 4 is connected during the reset period.
1, 42 apply a voltage to the auxiliary electrodes 20X and 20Y, whereby charges are accumulated in regions of the surface of the protective layer 19 facing the sustain electrodes 17X and 17Y, and then the auxiliary electrodes 2
By electrically disconnecting 0 from the pulse generation circuits 41 and 42, the accumulated charge is retained. The accumulated charges are formed at almost the same positions as the wall charges formed by the normal preliminary discharge, and similarly give a bias voltage to the sustain discharge. Therefore, the charge functionally equivalent to the wall charge formed by the preliminary discharge can be accumulated and retained regardless of the discharge, and light is not emitted during the reset period.
High-contrast display is possible.

[Second Embodiment] FIG. 8 is a configuration diagram showing a configuration of a panel portion of a plasma display device according to a second embodiment of the present invention, and FIG. 9 is a panel shown in FIG. It is sectional drawing in the II-II line of a part. In the following description, the same parts as those in the first embodiment will be designated by the same reference numerals, and the description thereof will not be repeated.

In the present embodiment, a case will be described in which auxiliary electrode 20 is arranged so as to accumulate charges corresponding to wall charges even in the discharge path of address discharge. As an example, the panel portion 50 of the plasma display device is provided with the auxiliary electrode 20Y having the same arrangement and shape as the first embodiment and the auxiliary electrode 20A arranged on the rear glass substrate 11 side. , Both form an equivalent capacitance. It is assumed that the auxiliary electrode 20A is located on the discharge space side of the address electrode 13A on the rear glass substrate 11, that is, inside the dielectric layer 14 here.

FIG. 10 shows the auxiliary electrode 2 in the panel section 50.
0A and 20A are arranged, (A) is a partial sectional view of the front glass substrate 12, and (B) is a rear glass substrate 1.
It is a top view of the No. 1 side. The shape and material of the auxiliary electrode 20A are also the same as those of the auxiliary electrode 2 in the first embodiment.
It can be considered in the same manner as 0 and can be appropriately selected in consideration of the charge capacity and the like, but here, it is set as shown in FIG. That is, in the auxiliary electrode 20A, the conductive portion CE made of a metal material is formed under the partition wall 15, and the charge holding portion CH made of ITO or the like is provided at a position facing the charge holding portion CH of the auxiliary electrode 20Y from both sides thereof. Formed. As described above, the charge holding portions CH of the auxiliary electrodes 20Y and 20A are formed in each pixel region and accumulate the charges of the same polarity as themselves on the mutually opposing surface side, but this charge is always the discharge path of the address discharge. It is supposed to exist inside.

The panel portion 50 is composed of the front glass substrate 1
When the auxiliary electrode 20 is formed on the second electrode, only the auxiliary electrode 20Y is formed except the auxiliary electrode 20X, and the auxiliary electrode 20A is formed on the rear glass substrate 11, and the first embodiment is different from the first embodiment. It can be manufactured similarly. The auxiliary electrode 20A is formed, for example, as follows.
After forming the address electrode 13A on the rear glass substrate 11, the dielectric layer 14 is formed to a predetermined thickness. Next, the charge holding portion CH of the auxiliary electrode 20A is patterned at a predetermined position above it to form the conductive portion CE. Then, when a dielectric layer 14 is further formed thereon with a predetermined thickness, an auxiliary electrode 20A is embedded inside the dielectric layer 14.

FIG. 11 shows a driving circuit of this plasma display device. The drive circuit is the pulse generation circuits 31 to 31.
3 and pulse generation circuits 42 and 43. The pulse generation circuit 43 is connected to the auxiliary electrode 20A via the switch S3, and applies a pulse voltage for accumulating charges. In the present embodiment, the pulse generation circuits 42 and 43 correspond to the "voltage applying section" of the present invention.

Next, the operation of such a plasma display device will be described with reference to FIGS. 9, 11 and 12A to 12F. FIG. 12 shows a voltage change in the panel section 50 from the start of operation to the address discharge. Here, assuming that the voltage −V _r is applied to the auxiliary electrode 20A as in the case of the auxiliary electrode 20X, the driving sequence in this case replaces the auxiliary electrode 20X in the first embodiment with the auxiliary electrode 20A. The voltage applied to each electrode is set in the same manner as in the first embodiment (FIG. 6).

(Reset period) First, the switches S2, S
3 is in the on state. First, the pulse generation circuits 42 and 43
As a result, when the predetermined pulse voltages −V _r and + V _r are applied to all the auxiliary electrodes 20Y and 20A, respectively, the charge holding portions CH corresponding to the potentials (−V _r and + V _r ) of each auxiliary electrode 20. Of electric charges are accumulated inside, the negative charges are accumulated in a region of the surface of the protective layer 19 facing the charge holding unit CH, and the negative charges are accumulated in a region of the surface of the dielectric layer 14 facing the charge holding unit CH. Charge is accumulated (FIG. 9).

When a sufficient amount of charge is accumulated, the switches S2 and S3 are opened (OFF state) and the auxiliary electrodes 20Y,
By floating 20A, the charge in each charge holding portion CH is fixed, and the charge on the surface of the protective layer 19 and the dielectric layer 14 accumulated in response to this is also held in each region. These are charges corresponding to wall charges. In this case, even after the switches S2 and S3 are opened, the protective layer 1
9, the potential by accumulated charges in the dielectric layer 14 respective surfaces (-V _r, + V _r) are generated, the potential difference therebetween becomes 2V _r.

Normally, the sustain electrode 1 is provided in the reset period.
The wall charges are formed by discharging 7X and 17Y, but in the present embodiment, the charges corresponding to the wall charges are accumulated / held. Further, here, since the potential difference between the protective layer 19 and the dielectric layer 14 is caused by both positive and negative accumulated charges, positive charges are generated on the sustain electrode 1 on the surface of the protective layer 19.
A potential difference that is about twice as large as that in the normal case of being fixed to the region facing 7X can be obtained.

(Address Period) Next, when the pulse voltage is applied from the pulse generating circuits 31 and 33 to the sustain electrode 17Y and the address electrode 13A corresponding to the pixels not to be displayed, the address discharge is generated between the both electrodes. Here, at the time of this address discharge, the apparent discharge start voltage is lowered between the protective layer 19 and the dielectric layer 14 due to the potential difference (2 V _r ) due to the accumulated charges. Therefore, the sustain electrode 17Y
The voltage V _s applied to the address electrode 13A and the voltage V _a applied to the address electrode 13A are set so that the potential difference (2V _r + V _s + V _a ) between the surfaces of the protective layer 19 and the dielectric layer 14 exceeds the discharge start voltage. It is sufficient that the applied voltage is lower than the conventional one.

After this address period, the switches S2, S
3 is turned on, and the auxiliary electrodes 20Y and 20A are connected to the pulse generation circuits 42 and 43. It should be noted that this connection timing may be until the next application of voltage to the auxiliary electrodes 20Y and 20A.

(Maintenance Period) In the subsequent sustaining period, this plasma display device operates in the same manner as in the first embodiment. However, the voltage difference due to the accumulated charges between the sustain electrodes 17X and 17Y is only −V _r given by the auxiliary electrode 20Y.

As described above, in the present embodiment, the auxiliary electrode 20Y is provided so that its charge holding portion CH faces the sustain electrode 17Y, and the auxiliary electrode 20A has its charge holding portion CH face the address electrode 13A. Since the auxiliary electrodes 20Y and 20A are connected to the pulse generating circuits 42 and 43, the pulse generating circuits 42 and 43 apply a voltage to the auxiliary electrodes 20Y and 20A during the reset period. Electric charges are accumulated in a region of the surface of the protective layer 19 facing the sustain electrode 17Y and a region of the surface of the dielectric layer 14 facing the address electrode 13A, and thereafter, the auxiliary electrode 20 is transferred from the pulse generating circuits 41 and 42. The accumulated charge is retained by electrically disconnecting. Of these, the region on the auxiliary electrode 20Y side where the charges are accumulated is in the path of the sustain discharge, and this accumulated charge is
A bias voltage for the sustain discharge is applied in the same manner as the wall charges formed by the normal preliminary discharge. Therefore, it is not necessary to perform preliminary discharge for forming wall charges, and no light is emitted during the reset period, so that the plasma display device can perform high-contrast display.

Further, here, the positive and negative accumulated charges that are formed are both present in the discharge path of the address discharge, and serve as a bias voltage for the address discharge. Therefore, the voltage applied to the sustain electrode 17Y and the address electrode 13A during the address discharge can be further lowered.

(Application Example) FIG. 13 is a sectional view showing a main part of a plasma display device according to an application example of the second embodiment. This application example is the panel unit 50 of the second embodiment.
On the other hand, the auxiliary electrode 20L is further provided. As described above, the sustain electrode 17 and the address electrode 13A are separated from each other by about 100 μm or more, and when the distance between the auxiliary electrode 20Y and the auxiliary electrode 20A is too long to store the charge as a capacitance between them, a sufficient amount. Charge is not formed. Therefore, the auxiliary electrode 20L is formed inside or on the surface of the partition wall 15 as a relay point between the two.

A pulse generating circuit 44 is connected to the auxiliary electrode 20L through a switch S4, and the auxiliary electrodes 20Y and 2Y are connected to each other.
0A, for example, a voltage having the same polarity as that of the auxiliary electrode 20Y is applied in the same manner as the auxiliary electrode 20Y. By doing so, the address discharge can be started more easily.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made. For example, in the above-described embodiment, the configuration in which positive and negative wall charges are formed at two locations by two or more auxiliary electrodes 20 has been specifically described, but the configuration in which the wall charges are formed at two or more locations is Not limited to the above embodiment, the auxiliary electrodes 20X, 20Y and 20
A may be provided at the same time, and auxiliary electrodes having three or more electrodes may be freely combined. Further, the sustain electrode 17 or the address electrode 13A may be combined with the auxiliary electrode 20 to apply a voltage, and the wall charges may be formed only on the auxiliary electrode 20 side. In that case, the auxiliary electrode 20 may be only one.

In the above embodiment, the case where the charges are accumulated in the discharge paths of both the sustain discharge and the address discharge has been described. However, for example, by providing only the auxiliary electrode 20A in the panel portion, only the address discharge can be performed. You may make it accumulate | store the electric charge which gives a bias voltage. As described above, the present invention is not limited to the case of accumulating charges that contribute only to the sustain discharge as in the case of the conventional wall charges, but may be used to assist discharge or to set the potential in the pixel region to a predetermined value. For control, the present invention is widely applicable to a plasma display device that changes the potential of a predetermined region by accumulating charges in the pixel region using an auxiliary electrode.

Further, the connection between the auxiliary electrode and the pulse generating circuit is not limited to the one described in the above embodiment, but various modifications are possible. Some of such connection forms will be described by representing the connection of the auxiliary electrode 20Y and the pulse generation circuit 42 in the first embodiment.

First, FIG. 14 shows a case where a resistor 81 is added in series between the auxiliary electrode 20Y and the switch S2. When the switch S2 is opened, the charge accumulated in the auxiliary electrode 20Y will flow out if the resistance value is low, but the resistor 81 provided in series with the switch S2 has a function of blocking this. Therefore, it is desirable that the resistor 81 have a resistance value as high as possible. However, the load seen from the pulse generation circuit 42 when the switch S2 is conductive is the resistor 81,
And the resistance value of the resistor 81 must be set so that the CR time constant of the capacitance component between the auxiliary electrode 20Y and another electrode such as the sustain electrode 17 can sufficiently transmit the output waveform from the circuit 42. is there.

Further, FIG. 15 shows a case where a resistor 82 is added in parallel between the auxiliary electrode 20Y and the switch S2. The other end of the resistor 82 has a predetermined potential, for example, the pulse generation circuit 4
By setting the level of the entire drive circuit including 2 as the ground level, it functions as a pull-up / down resistor. Therefore,
It is possible to prevent the potential of the auxiliary electrode 20Y from becoming unstable after the switch S2 is opened, and it is possible to stably discharge in the address period. In addition, this resistor 8
If the resistance value of 2 is too small, the electric charge stored in the auxiliary electrode 20Y will flow out through this, so it is desirable to set the resistance value to a sufficiently high value suitable for storing the electric charge.

FIG. 16 shows the auxiliary electrode 20Y and the switch S2.
This is the case where the capacitor 83 is added in parallel between the two. The other end of the capacitor 83 is set to a predetermined potential, for example, the ground level of the entire drive circuit including the pulse generation circuit 42. Similarly to the above-described resistor 82, the capacitor 83 also prevents the potential of the auxiliary electrode 20Y from becoming unstable after the switch S2 is opened, and further supplies the electric charge to the discharge region through the auxiliary electrode 20Y to discharge. At that time, there is an effect that a sufficient amount of electric charge is secured and stable discharge is performed in the address period. In particular, the auxiliary electrode 20L in the application example of the second embodiment is difficult to store a large amount of charge due to its structure, and the capacitor can be effectively used for this.

FIG. 17 shows a case where the diode 84 is connected to the auxiliary electrode 20Y instead of the switch S2. If the pulse generation circuit 42 always applies a negative pulse voltage, in the diode 84 connected in the direction as shown in the figure, when a pulse is applied, a current flows from the auxiliary electrode 20Y toward the pulse generation circuit 42, The potential of the auxiliary electrode 20Y decreases, and a reverse voltage is applied when no pulse is applied,
It is turned off. Therefore, it is possible to realize the same charge holding function as in the above-described modified examples with a circuit configuration simpler than the case of using the switch S2. The resistor 8 described above
A plurality of the capacitors 1, 82, the capacitors 83, and the diodes 84 may be used, or some of them may be used in combination. The capacitor 83 and the diode 84 are respectively the “capacitance element” in the present invention,
It corresponds to "rectifier element".

Further, FIG. 18 shows a case where the reference potential of the pulse generating circuit 42 is wired so as to be equal to the output potential of the pulse generating circuit 31. In the modification so far, the load in the pulse generating circuit 42 has a capacitance component between the auxiliary electrode 20Y and the reference potential in addition to the capacitance component between the sustain electrode 17 and the auxiliary electrode 20Y. Since the component is removed, the power consumption of the drive circuit can be reduced and the scale of the drive circuit can be reduced.

As described above, the same modification as that of the example described with reference to FIGS. 14 to 18 can be applied to an electrode having a charge holding portion other than the auxiliary electrode 20Y.
Needless to say, the present invention is not limited to the plasma display device of the above embodiment and can be applied to all the plasma display devices of the present invention.

In addition, although the plasma display device having a discharge gap of less than 50 μm has been described in the above embodiment, the present invention can be applied to an AC type plasma display device having another structure.

[0063]

As described above, according to the plasma display device of the present invention, the auxiliary electrode having the charge holding portion in each pixel region and formed in the region between the sustain electrode pair and the address electrode. And a voltage applying section for applying a voltage to the auxiliary electrode, charge is accumulated in a predetermined area in each pixel region by applying a voltage to the auxiliary electrode from the voltage applying section, Is controlled. Since the charges accumulated in the region where the wall charges are normally formed are functionally equivalent to the wall charges, this plasma display device can operate without performing the preliminary discharge, and the plasma display device can emit light during the reset period. It is possible to prevent a decrease in contrast. In addition, since the auxiliary electrode accumulates electric charge in an arbitrary region in each pixel region, it gives a desired bias voltage to both sustain discharge and address discharge, and each discharge can be generated more easily. ,
It is possible to lower the applied voltage at the start of discharge.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main configuration of a plasma display device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the panel section shown in FIG. 1 taken along line I-I.

FIG. 3 is a plan view for explaining the shape of an auxiliary electrode in the panel section shown in FIG.

4A and 4B are diagrams showing a structure of an auxiliary electrode in the panel portion shown in FIG. 1, FIG. 4A being a partial sectional view of the panel portion,
(B) is a plan view of (A).

5 is a cross-sectional view showing a drive circuit connected to the panel section shown in FIG.

6 is a diagram showing voltage waveforms input from a drive circuit to the panel unit shown in FIG.

FIG. 7 is a diagram showing a voltage change in the panel section shown in FIG. 1.

FIG. 8 is a perspective view showing a main configuration of a plasma display device according to a second embodiment of the present invention.

9 is a cross-sectional view taken along line II-II of the panel unit shown in FIG.

10 is a diagram showing a structure of an auxiliary electrode in the panel section shown in FIG. 8, (A) is a partial sectional view of the panel section,
(B) is a plan view of (A).

11 is a cross-sectional view showing a drive circuit connected to the panel section shown in FIG.

12 is a diagram showing a voltage change in the panel section shown in FIG.

13 is a cross-sectional view showing an application example of the plasma display device shown in FIG.

14 is a cross-sectional view showing a modified example of the plasma display device shown in FIG.

15 is a cross-sectional view showing a modified example of the plasma display device shown in FIG.

16 is a cross-sectional view showing a modified example of the plasma display device shown in FIG.

17 is a cross-sectional view showing a modified example of the plasma display device shown in FIG.

18 is a cross-sectional view showing a modified example of the plasma display device shown in FIG.

FIG. 19 is a perspective view showing a main part of a conventional plasma display device.

20 is a diagram for explaining a general driving method of the plasma display device shown in FIG.

[Explanation of symbols]

10, 50 ... Panel part, 11 ... Rear glass substrate, 12 ...
Front glass substrate, 13A ... Address electrode, 14 ... Dielectric layer, 15 ... Partition wall, 16 ... Phosphor layer, 17, 17X, 17
Y ... Sustain electrode, 18 ... Dielectric layer, 19 ... Protective layer, 20,
20X, 20Y, 20A, 20L ... Auxiliary electrode, 21 ... Bus electrode, 31-33, 41-44 ... Pulse generation circuit, 8
1, 82 ... Resistance, 83 ... Capacitor, 84 ... Diode, S1 to S4 ... Switch, CH ... Charge holding section, CE ...
Conductive part.

Claims (12)

[Claims] 1. A pair of sustain electrodes, of a first substrate and a second substrate which are arranged to face each other, paired on the first substrate via a discharge gap, and on the second substrate. In a plasma display device in which address electrodes are provided, and a pixel is formed in a region where the sustain electrode pair intersects with the address electrode, a charge holding portion is provided in each pixel region, and a space between the sustain electrode pair and the address electrode is provided. 2. A plasma display device, comprising: an auxiliary electrode formed in the region of 1. and a voltage applying section for applying a voltage to the auxiliary electrode. 2. The plasma display device according to claim 1, wherein the auxiliary electrode has the charge holding portion on at least one side in a width direction. 3. The plasma display device according to claim 1, wherein the auxiliary electrode is arranged so as to accumulate charges in a discharge path generated in the sustain electrode pair. 4. The auxiliary electrode is arranged so as to accumulate charges in a path of a discharge generated between one of the sustain electrode pair and the address electrode. Plasma display device. 5. A protective layer is provided on the sustain electrode pair, and at least one of the auxiliary electrodes is provided between the protective layer and the sustain electrode pair or inside the protective layer. The plasma display device according to claim 1, which is characterized in that. 6. A dielectric layer is provided on the address electrode, and at least one of the auxiliary electrodes is provided between the dielectric layer and the address electrode or inside the dielectric layer. The plasma display device according to claim 1, wherein: 7. A partition for partitioning a discharge space is provided between the first substrate and the second substrate, and the auxiliary electrode is provided on a side surface or inside of the partition. The plasma display device according to claim 1. 8. The plasma display device according to claim 1, wherein a resistor is provided between the auxiliary electrode and the voltage applying section. 9. The plasma display device according to claim 1, wherein a capacitive element is provided between the auxiliary electrode and the voltage applying section. 10. A rectifying element is provided between the auxiliary electrode and the voltage applying section.
The plasma display device described. 11. The plasma display device of claim 1, wherein the discharge gap is less than 50 μm. 12. The plasma display device according to claim 1, wherein the discharge gap is 20 μm or less.