JPS5833560B2 - Plasma display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a driving method for a plasma display panel in which an upper member and a lower member facing each other across a gas discharge space are constructed asymmetrically in terms of structure or material. In particular, the present invention relates to a new writing method for writing with less voltage.

As is well known, a plasma display panel consists of a substrate, each insulating, a plurality of parallel electrodes disposed on its surface, and a dielectric layer covering the electrodes. A pair of members are arranged facing each other with their respective electrodes crossing each other, and an ionizing gas is filled in a gap provided between the two members.

In such a configuration, in the gas-filling gap, a plurality of discharge points are formed in a matrix shape across the gas space at each intersection of both the electrodes, and each of these discharge points, when discharged, It has an inherent memory due to wall charges attached to the layer surface.

According to the normal driving method for the above plasma display panel, an electrode included in one member (hereinafter referred to as the X electrode) and another electrode included in the other member (hereinafter referred to as the Y electrode) are connected.
With an alternating maintenance voltage applied between the electrodes),
A write voltage exceeding the discharge starting voltage is applied between the selected X electrode and Y electrode.

Thus, a discharge occurs at the discharge point at the intersection of the selected X electrode and Y electrode, and this discharge is thereafter maintained by the alternating sustain voltage until an erase voltage is applied.

In this case, a typical plasma display panel is
Since the upper member and the lower member across the gas space are symmetrical in terms of structure and material, the selected XSY
The polarity of the write voltage to the electrodes is independent of the effects occurring across the gas.

In other words, the absolute value of the voltage required for writing is the same regardless of whether the X electrode or the Y electrode is positively or negatively energized.

On the other hand, recent developments in this type of technology have provided plasma display panels in which an upper member including an X electrode and a lower member including a Y electrode are asymmetrically constructed in terms of structure or material. .

For example, in a plasma display panel in which a phosphor is added on one dielectric layer in order to display by converting discharge light into another color, the structure of the X electrode side and the Y electrode side is asymmetrical. Become.

Furthermore, as another example, a structure has been proposed in which the dielectric layer covering the X electrode and the dielectric layer covering the Y electrode are made of different materials or have different thicknesses.

Furthermore, there is also a plasma display panel with an asymmetrical structure in which the pitch of the X electrode and the Y electrode or the width of the electrodes are different in order to display a special pattern.

Even in such an asymmetrically structured plasma display panel, the electrodes are insulated from the gas space by a dielectric layer and are driven by an alternating voltage, which is the same as in the symmetrically structured plasma display panel described above. Therefore, it may seem that the magnitude of the voltage required for writing is independent of its polarity.

However, the present inventors have discovered that plasma with an asymmetric structure
It has been found that when driving a display panel, the magnitude of the voltage required for writing differs depending on how the polarity of the writing voltage is selected.

Therefore, an object of the present invention is to provide a driving method that can write information with a reduced write voltage when writing information to a plasma display panel that is vertically asymmetrical in terms of structure or material. It is on offer.

Another object of the present invention is to create a plasma with an asymmetric structure.
Three voltages required to drive the display panel,
That is, the load on the drive circuit is reduced by lowering the highest write voltage among the write, erase, and sustain voltages.

Briefly stated, the present invention is based on the recognition that if the materials or structures of the dielectric layers covering the electrodes are different in the upper and lower members, the surfaces in contact with the gas will exhibit different secondary electron emission coefficients from each other. .

Note that the term "dielectric layer" herein refers to all layers, including single layers and multilayers, that directly or indirectly cover the electrode, regardless of the function of each layer, in whole or in part. used as something.

For such plasma display panels,
The side electrode covered with a dielectric layer having a surface with a high secondary electron emission coefficient is selected to have negative polarity, and the side electrode covered with a dielectric layer having a surface with a low secondary electron emission coefficient is selected to have a positive polarity. A write voltage is applied depending on the polarity.

Furthermore, if the pitch or width of the X and Y electrodes is different, there will be a difference in the electric field distribution on the surfaces of the dielectric layers on both sides, so the electrode on the side with higher electric field concentration is selected to be negative. The lower electrode thereof is selected to have positive polarity and a write voltage is applied.

This invention is advantageous when applied to a plasma display panel with an asymmetric structure, and as such a plasma display panel with an asymmetric structure, CI)
There are cases in which the structures or materials of the dielectric layers included in both CID members are different, and cases in which the configurations of electrodes included in both CID members are different.

CI,) categories include, for example, (a) a type in which a phosphor is provided on one dielectric layer for color conversion; and (b) a type in which one dielectric layer is made opaque or black to improve contrast. (C) A protective layer or other layer is provided on one dielectric layer to protect its surface from ion bombardment. Type: (d) Includes a type in which the dielectric layers have different thicknesses in order to create a difference in the amount of wall charge accumulated on both dielectric layers.

Category 'J-Cn) is a type in which (e) one electrode width is wider than the other in order to display a special pattern such as a line; (f> to display a character with a special font) This includes types in which one electrode pitch is wider than the other electrode pitch.

FIG. 1 shows a cross section of a main part of a plasma display panel of the type described in (a) above. It is composed of side members.

The upper member is mainly composed of a transparent insulating substrate 1 and includes a plurality of X electrodes 2 arranged in parallel on the substrate.

Further, the X electrode is covered with a dielectric layer 3 such as low melting point glass.

The lower member is also mainly composed of an insulating substrate 1a, on which a plurality of parallel Y layers whose surfaces are covered with a dielectric layer 3a.
It includes an electrode 2a.

The X electrode 2 and the Y electrode 2a are placed in a relationship that is orthogonal to each other, and a discharge point that crosses the discharge space is formed at each intersection between the two electrodes.

As mentioned above, the upper and lower members are symmetrical, but in FIG. 1 the phosphor 5 is coated on top of the dielectric layer 3 comprised in the upper member.

Thus, the plasma display panel of FIG. 1 has an asymmetric structure.

A plasma display with an asymmetric structure as shown in Figure 1
When driving the panel, according to the present invention, the X electrode 2 included in the upper part has a positive or relatively high potential,
A write voltage is applied such that the Y electrode 2a included in the lower member has a negative or relatively low potential.

More specifically, during the write operation, as shown in FIG. When a voltage is selectively applied so that the X electrode on the side coated with has a positive potential Vs and the Y electrode has a negative potential Vw, the discharge point installed at the intersection of the selected X electrode and Y electrode will have a , 1 +VSI + I -Vwl=V.

A write voltage of 1 is applied, and when this write voltage exceeds the ignition voltage, a discharge occurs.

According to experiments conducted by the present inventors, in a plasma display panel having an asymmetrical structure in which a phosphor is added as shown in FIG. The write voltage VWt was 270v.

That is, from the selected X electrode the same as the sustain voltage 170
A satisfactory write operation was achieved by applying a positive voltage of V and a negative voltage of 100 V from the selected Y electrode.

However, for the same plasma display panel, if the polarity of the writing voltage is reversed as shown in FIG. It was necessary to apply a write voltage of 340 V between the X electrode and the Y electrode.

This fact means that depending on the polarity of the write voltage, the magnitude of the voltage required for writing can be reduced by approximately 20%.

In a plasma display panel with an asymmetric structure, the magnitude of the voltage required for writing depends on the polarity of the writing voltage. First, the secondary electron emission coefficient of the surface of the dielectric layer in contact with the gas is higher than that of the upper member. This is thought to be due to the difference between the lower part and the lower member.

Applying a negative potential to one electrode covered with a dielectric layer having a high secondary electron emission coefficient, and applying a positive potential to the other electrode covered with a dielectric layer having a low secondary electron emission coefficient. When the secondary electrons are emitted from the dielectric surface with a high secondary electron emission coefficient by ion bombardment or electron bombardment, they are attracted by the positive potential of the opposing electrodes, pass through the gas space, and collide with gas molecules. While repeating, effectively excite it.

However, if the polarity was opposite, more 2
The secondary electrons will be pulled back by the positive potential without contributing to the excitation of the gas molecules.

For the above reasons, if there is a relationship r The voltage on the X side and Y side during writing is VWX, respectively.
, VWY, (1) When the polarity of the write voltage is selected in the relationship vwx-VWY>O, that is, as shown in Figure 2 A (the write voltage is applied so that the X electrode is at a relatively high potential). The voltage required for writing at the time is expressed by vwI: (2) The polarity of the write voltage is set in the relationship of VwX-vwY<O, that is, the write voltage is set so that the X electrode side has a relatively low potential as shown in Figure 2B. When the voltage required for writing when is applied is expressed as vw2, there is a relationship of vwl<vw2 between the voltages required for writing.

Therefore, in the plasma display panel shown in FIG. 1, the dielectric layer 3a made of low melting point glass of the lower member has a higher secondary electron density than the phosphor 5 provided on the upper member. Since it has a radiation coefficient, X
It is recommended to write with a polarity in which the electrode side is positive.

In addition, other types included in the aforementioned category [■]
When driving an asymmetrically structured plasma display panel such as b) and KC), according to the present invention, the polarity is such that the electrode on the side having the dielectric surface with a high secondary electron emission coefficient has a relatively high potential. A write voltage is applied at .

The second reason for the polarity dependence of the voltage required for writing is between the X electrode and the Y electrode.
If the arrangement pattern with the electrodes is asymmetrical, this also appears because the degree of concentration of the electric field is different on the surfaces of both dielectric layers.

For example, when the width of the X electrode is formed wider than the Y electrode, the electric field across the gas at each discharge point has a spread distribution on the dielectric layer surface on the X electrode side.

In other words, the lines of electric force are concentrated at a higher density on the surface of the dielectric layer on the narrower Y electrode side.

Therefore, if the Y electrode is negatively energized, high-energy secondary electrons can be emitted from the dielectric layer surface due to strong ion bombardment, and writing can be performed at a lower voltage than in the case of the opposite polarity. can.

For the same reason, in the type (f) plasma display panel with different electrode pitches, the electrode on the narrower side of the pinch is selected to have negative polarity and a write voltage is applied.

In addition, for type (d) panels with different dielectric layer thicknesses, the concentration of the electric field is higher on the thinner dielectric layer side, so the electrode covered with this thinner dielectric layer becomes negative. Apply write voltage with polarity.

As is clear from the above description, according to the present invention, writing can be achieved with a low writing voltage when driving an asymmetrically structured plasma display panel.

Reducing the write voltage, which is required as the highest level voltage, reduces the burden on transistors and other circuit components used for driving, and is useful for constructing inexpensive circuits.

It goes without saying that various other modifications are possible.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a plasma display panel to which the present invention is applied, and FIG. 2 is an explanatory diagram of the operation of the panel of FIG. 1. In the figure, 1 and 1a are substrates, 2 and 2a are electrodes, 3 and 3a are insulating layers, 4 is a discharge space, 5 is a phosphor layer, VW2
is the write pulse.

Claims (1)

[Claims] 1. A first gas disposed facing each other across an ionizable gas space.
and a second member, the first member having a plurality of X electrodes covered with a first dielectric layer having a surface in contact with the gas, and the second member including a first dielectric layer. Covered with a second dielectric layer having a surface with a secondary electron emission coefficient larger than the secondary electron emission coefficient of the surface, and having a plurality of Y electrodes arranged in a direction crossing the X electrodes. A method for driving a plasma display panel having an asymmetric configuration, wherein when applying a write voltage to a selected electrode intersection with sustaining voltage pulses being applied alternately to the X electrode and the Y electrode, the secondary electron emission is A method for driving a plasma display panel, characterized in that a write voltage is applied such that the Y electrode side covered with a second dielectric layer having a surface with a large coefficient has a relatively negative polarity. 2. The first gases are arranged opposite to each other across the ionizable gas space.
and a second member, the first member having a plurality of X electrodes covered with a first dielectric layer having a surface in contact with the gas, and the second member having another X electrode in contact with the gas. a plurality of Y electrodes covered with a second dielectric layer having a surface and arranged in a direction crossing the X electrodes;
and asymmetrically configured such that when a voltage is applied between the X and Y electrodes, the electric field across the gas space is concentrated to a higher degree at the surface of the second dielectric layer than at the surface of the first dielectric layer. 2. A method for driving a plasma display panel in which a write voltage is applied to a selected electrode intersection while sustaining voltage pulses are applied alternately to the X electrode and the Y electrode. A method for driving a plasma display panel, characterized in that a write voltage is applied such that the Y electrode side under the second dielectric layer, which is higher, has a relatively negative polarity.