JP3760593B2 - Plasma display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a discharge gas of a plasma display (hereinafter referred to as PDP) apparatus, and further relates to a stabilizing gas.
[0002]
[Prior art]
For driving a PDP, for example, as disclosed in Japanese Patent Laid-Open No. 4-332430, a method of selecting a cell to emit light according to a preliminary discharge period and an address period before discharge is generally used. It is necessary to form a charge. However, excited Xe * atoms remain in the plasma even after the discharge is completed, and electrons collide with the MgO protective film to generate electrons. Since the lifetime of the Xe * atoms is very long and is about the same as the time required for the preliminary discharge period and the writing period, the electrons generated after the end of the discharge hinder the formation of electric charges during the writing discharge.
[0003]
Therefore, the configuration is not always satisfactory in terms of stable light emission.
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide means capable of reducing erroneous discharge.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, means for adding a gas such as O2, N2, CO2, CF4, H2 or the like to He, Ne, Ar, Kr, Xe, etc., which are the main components of the gas that generates plasma in the PDP cell Is used.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS.
[0007]
FIG. 2 is an exploded perspective view showing a part of the structure of the PDP to which the present invention is applied. Transparent common electrodes (hereinafter referred to as X electrodes) 22-1 to 22-2 are formed on the lower surface of the front glass substrate 21, and FIG. Transparent independent electrodes (hereinafter referred to as Y electrodes) 23-1 to 23-2 are attached. Further, X bus electrodes 24-1 to 24-2 and Y bus electrodes 25-1 to 25-2 are stacked on the X electrodes 22-1 to 22-2 and the Y electrodes 23-1 to 23-2, respectively. . Further, the X electrodes 22-1 to 22-2, Y electrodes 23-1 to 23-2, X bus electrodes 24-1 to 24-2, and Y bus electrodes 25-1 to 25-2 are covered with a dielectric 26. A protective layer 27 such as MgO is attached.
[0008]
On the other hand, on the upper surface of the rear glass substrate 28, electrodes (hereinafter referred to as A electrodes) 29 that are three-dimensionally intersected with the X electrodes 22-1 to 22-2 and the Y electrodes 23-1 to 23-2 are attached. The A electrode 29 is covered with a dielectric 30, and a partition wall 31 is provided on the dielectric 30 in parallel with the A electrode 29. Further, the phosphor 32 is applied to the inside of the portion sandwiching the A electrode 29 in the concave region formed by the wall surface of the partition wall 31 and the upper surface of the dielectric 30.
[0009]
FIG. 3 is a cross-sectional view of the PDP viewed from the direction of the arrow D1 in FIG. 2, and shows one cell which is the minimum unit of the pixel.
[0010]
As shown in FIG. 3, the A electrode 29 is positioned between the two partition walls 31, and the front glass substrate 21, the rear glass substrate 28, and the discharge space 33 surrounded by the partition walls 31 are filled with a gas for generating plasma.
[0011]
The discharge space 33 may be spatially separated by the partition wall 31 or may be spatially continuous by providing a gap between the partition wall 31 and the discharge space side surface of the front glass substrate 21.
[0012]
FIG. 4 is a cross-sectional view of the PDP viewed from the direction of the arrow D2 in FIG. 2, and shows one cell. The cell boundary is the position indicated by the dotted line. From FIG. 4, 3 is an electron, 4 is a positive ion, 5 is a positive wall charge, and 6 is a negative wall charge.
[0013]
FIG. 4 shows a schematic diagram in which a positive voltage is applied to the A electrode 29 and the Y electrode 23-1, and a negative voltage is applied to the X electrode 22-1 as an example. If electrons 3 and positive ions 4 remain in the discharge space in this state, the positive wall charges 5 and the negative wall charges 6 are erased, and writing is inhibited.
[0014]
FIG. 5 is a diagram showing an operation in one field period required to display one image on the PDP shown in FIG. 2. The 1TV field period 40 is divided into a plurality of subfields 41 to 48, and each subfield As shown in (b), it comprises a preliminary discharge period 49, an address discharge period 50 for defining the light emitting cells, and a light emitting display period 51. A waveform 52 is a voltage waveform applied to one A electrode in the write discharge period 50 according to the prior art, a waveform 53 is a voltage waveform applied to the X electrode, and 54 and 55 are i-th and (i + 1) -th of the Y electrode. It is a voltage waveform to apply, and each voltage is set to V0, V1, and V2 (V).
[0015]
From FIG. 5, when the scan pulse 56 is applied to the i-th row of the Y electrode, the write discharge occurs in the cell located at the intersection with the A electrode 29.
[0016]
When the scan pulse 56 is applied to the i-th row of the Y electrode, if the A electrode 29 is at the ground potential, no write discharge occurs and the cell becomes a non-light emitting cell.
[0017]
In this manner, in the write discharge period 50, a scan pulse is applied once to the Y electrode, and the A electrode 29 becomes V0 in the light emitting cell and the ground potential in the non-light emitting cell corresponding to the scan pulse.
[0018]
Heretofore, an example of the PDP configuration to which the present invention is applied has been shown.
[0019]
FIG. 1 is a view showing an embodiment of the present invention and shows a state of charged particles after the end of discharge. In FIG. 1, 1 is a metastable Xe atom Xe *, 2 is a neutral gas molecule or atom, 3 is an electron, and 4 is a positive ion. The arrow extending from Xe * 1 and the electron 3 represents the direction of movement of each particle.
[0020]
The state of atoms and electrons after the end of discharge will be described using the case of a mixed gas of Xe and Ne, which is a general PDP gas composition. As an example, it is assumed that the gas pressure is 300 Torr and the Xe partial pressure is about 18 Torr. In the plasma, many Ne exist as metastable states Ne * or positive ions Ne +. Similarly, many Xe exist as Xe * or Xe +. Ne + is 0.33 μs, Ne * is 0.023 to 0.078 μs, and the internal energy is given as Xe +. Further, this Xe + is about 0.1 μs and is almost absorbed by the X electrodes 22-1 to 22-2, the Y electrodes 23-1 to 23-2, and the A electrode 29, and a part of the Xe + recombines with electrons. Xe ** or Xe *. When a voltage of about 100 V is applied, electrons are absorbed by the electrode on the order of ns or less.
[0021]
Next, a discharge cycle in the PDP will be described in order to examine whether particles having such a lifetime affect the driving of the PDP. As shown in FIG. 5, in the PDP, gradation is expressed by dividing one TV field 40 (1/60 s = 16.7 ms) into subfields 41 to 48 having a plurality of different light emission times. As described above, each subfield has a preliminary discharge period 49, an address discharge period 50, and a light emission display period 51. When the subfield is divided into eight as shown in FIG. 5, the total time of the preliminary discharge period 49 and the write discharge period 50 is about 1.8 ms, and the light emission display period 51 that actually emits light is about at least short. 10 μs or more. Therefore, the phenomenon of 1 μs or less described above does not affect the discharge.
[0022]
However, the lifetime of Xe * is very long as about 1.85 ms, and since it is a neutral particle, it cannot be erased in the preliminary discharge period 49. Further, since Xe ** also becomes Xe * at 0.017 to 0.055 μs, the input energy is Xe + is X electrodes 22-1 to 22-2, Y electrodes 23-1 to 23-2, and A electrode. If the amount absorbed by 29 is removed, it will eventually concentrate on Xe *. In addition, since a large number of Xe * are generated by direct excitation by electrons, the number is very large. As a result, Xe * collides with the MgO protective layer 27 as shown in FIG. 1 and emits secondary electrons. The secondary electrons may increase charged particles (electrons, ions) by colliding with neutral particles, even if they do not lead to discharge. Thus, the charged particles generated after the end of the discharge erase the wall charges that are to be formed in the preliminary discharge period 49 and the write discharge period 50.
[0023]
As a countermeasure against such a problem, a stabilizing gas having an energy level lower than Xe * is used. That is, the energy of Xe * is given to the stabilizing gas, and the deactivation of Xe * is promoted. Since the stabilizing gas is a molecule, it has a low energy level, and its internal energy can be lowered below the work function of the MgO interface, and emission of secondary electrons can be reduced. The energy of the metastable level of Xe * is EM1 = 8.32 eV and EM2 = 9.45 eV from the lowest. Therefore, as a characteristic of the stabilizing gas, it is necessary to have an electron energy level equal to or lower than EM2 or EM1.
[0024]
Here, with respect to the mixing ratio of the stabilizing gas to the gas for generating plasma, an example in which Ne and Xe mixed gas are used as the gas for generating plasma and O2 is used as the stabilizing gas will be described. According to the experimental result of the above example, the result is that the efficiency is very poor when 0.1% or more of O2 is mixed. This is considered to be because the energy deactivation from Ne or Xe to O2 is too large. On the contrary, at the mixing ratio of 0.1% or less, a large decrease in efficiency could not be seen. Therefore, when O2 is added to the Ne and Xe mixed gas, the mixing ratio of O2 is about 0.1%. However, considering the mixing accuracy and the like, it is more practical to keep it at about 0.01%.
[0025]
The above contents can be regarded as substantially the same when other elements or a plurality of elements are used for the gas for generating ultraviolet rays, the base gas, and the stabilizing gas.
[0026]
【The invention's effect】
By applying the present invention, deactivation of excited Xe atoms that cannot be controlled by an electric field can be promoted, secondary electrons generated by the excited Xe atoms can be suppressed, and erroneous discharge can be reduced. realizable.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention. FIG. 2 is an exploded perspective view showing a part of the structure of a plasma display panel of the present invention. FIG. 3 is a plasma display viewed from the direction of arrow D1 in FIG. 4 is a cross-sectional view of the plasma display panel as viewed from the direction of the arrow D2 in FIG. 2. FIG. 5 is a diagram showing the operation during one field period constituting one image.
DESCRIPTION OF SYMBOLS 1 ... Metastable Xe atom 2 ... Neutral atom or molecule 3 ... Electron 4 ... Positive ion 5 ... Positive wall charge 6 ... Negative wall charge 21 ... Front glass substrate 22-1 thru | or 22-2 ... X electrode 23-1 thru | or 23 -480 ... Y electrodes 24-1 to 24-2 ... X bus electrodes 25-1 to 25-2 ... Y bus electrodes 26 ... dielectric 27 ... protective layer 28 ... back glass substrate 29 ... A electrode 30 ... dielectric 31 ... Partition 32 ... Phosphor 33 ... Discharge space 40 ... 1 TV fields 41 to 48, 41-1 to 48-1, 41-2 to 48-2 ... Subfields 49, 49-1, 49-2 ... Predischarge period 50, 50-1, 50-2: Write discharge period 51 ... Light emission display period 52 ... Voltage waveform 53 applied to one A electrode 53 ... Voltage waveform 54 applied to X electrode ... Voltage waveform 55 applied to i-th electrode of Y electrode ... Voltage waveform 56 applied to i + 1th electrode of Y electrode ... i-th row of Y electrode A scan pulse 57 applied to the scan electrode 60 applied to the (i + 1) th row of the Y electrode ... a discharge electrode 61 ... a dielectric 62 ... a discharge space

Claims (7)

A means for generating plasma, a means for generating ultraviolet light by the plasma, and a means for generating visible light by the ultraviolet light, and a gas for generating the plasma is at least a part of the constituent elements,
In a plasma display apparatus , one TV field period is divided into a plurality of subfields, and one subfield is composed of a preliminary discharge period, an address discharge period, and a light emitting display period .
Includes a gas for generating said ultraviolet as at least a part of the gas for generating the plasma, in order from the lower energy of the metastable level of the gas for generating the ultraviolet rays and E M1, E M2 (E M1 <E M2) A plasma display device , wherein a stabilizing gas having an energy level lower than that of EM2 is added to a gas that generates the plasma. In the plasma display apparatus according to claim 1, the gas having a level of lower than the EM1 energy, plasma display device, characterized in that added to the gas for generating the plasma. 2. The plasma display device according to claim 1, wherein the gas that generates ultraviolet rays is Xe. 2. The plasma display device according to claim 1, wherein the stabilizing gas is any one of CO2, N2, O2, CF4, and H2, or a mixed gas thereof. 5. The plasma display device according to claim 4, wherein the stabilizing gas is O2, and the pressure (partial pressure) of O2 is 0.1% or less of the total pressure. 5. The plasma display device according to claim 4, wherein the stabilizing gas is O2, and the pressure (partial pressure) of O2 is 0.01% or less of the total pressure. 5. The plasma display device according to claim 4, wherein the stabilizing gas is CO2, and the pressure (partial pressure) of CO2 is 0.1% or less of the total pressure.

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