WO1998014976A1

WO1998014976A1 - Discharge accelerant gas mixtures and plasma display panels using such mixtures

Info

Publication number: WO1998014976A1
Application number: PCT/US1997/017533
Authority: WO
Inventors: Kevin J. Ilcisin; Thomas S. Buzak; Paul C. Martin
Original assignee: Technical Visions, Inc.
Priority date: 1996-09-30
Filing date: 1997-09-30
Publication date: 1998-04-09
Also published as: AU4603397A

Abstract

A plasma display panel using gas mixtures are provided. The gas mixtures include a mixture of a primary discharge gas and a discharge accelerant gas. Discharge accelerant gases include nitrogen and hydrogen, and primary discharge gases include helium, nitrogen, xenon, argon and krypton. The primary discharge gases have primary discharge initiation times that are reduced in combination with a discharge accelerant gas. A combination of the discharge accelerant gases with the primary gases reduces the discharge initiation time when combined over a wide range of relative proportions by volume.

Description

DISCHARGE ACCELERANT GAS MIXTURES AND PLASMA DISPLAY PANELS USING SUCH MIXTURES

Field of the Invention

The present invention relates to plasma display panels and, in particular, to a

discharge gas combination for improving the performance of such display panels.

Background of the Invention

Flat panel displays are desirable because they are compact. One type of flat

panel display sometimes referred to as a matrix addressed display typically includes

two sets of orthogonal addressing structures (row electrodes and column electrodes)

with a light modulator or a light generator at the intersections of the row and column

electrodes. The light modulators/generators at the electrode intersections form picture

elements (pixels) that create a displayed image.

Common optical modulators include liquid crystals, which control the passage

of light emitted from a light source. Typical light generators include gases or

phosphors. It is known that gases may be used either directly as visible light emitters

or as ultraviolet (invisible) light emitters that activate an associated phosphor to

convert the ultraviolet light into visible light. One type of flat panel display, referred

to as a plasma-addressed liquid crystal display (PALC) and described in U.S. Patent

No. 4,896,149 of Buzak et al. , uses a gas discharge to control liquid crystals rather

than as a light generator.

Images are written or formed on the display by applying voltages to the row

and column electrodes to control the light modulator/generator at each pixel. The

voltages applied to the pixels correspond to the visual qualities of the intended image. If a light modulator such as a liquid crystal is used, the applied voltage controls the

amount of light from a light source passing through a pixel. If a light generator is

used, the applied voltage controls the amount of light that is generated by a pixel.

In a typical matrix addressed display, a set of row electrodes is formed on a

flat nonconductive plate, and a set of column electrodes is similarly formed on another

flat nonconductive plate. For transmissive displays, both plates are transparent; for

emissive or reflective displays, only one of the plates need be transmissive. Glass is

commonly used for the plates, but plastic is used in some applications. One or both

sets of electrodes may be transparent. Insulating spacers hold the plates apart and the

gap or cavity between the plates contains the active material of the light

modulator/generator. For example, in a gas discharge display, a dischargeable gas or

gas mixture fills the gap. In a liquid crystal display, a liquid crystal fills the gap.

Many variations of this simple matrix structure are known.

There are two basic types of gas discharge flat panel displays, which are also

known as plasma display panels (PDPs). One type is the DC plasma display panel

(DC PDP). It has simple crossed row and column electrodes spaced apart with

dielectric barriers, the barriers serving both to space the electrodes and to confine the

discharge to a single pixel. The space between the electrodes is filled with a

dischargeable gas, usually neon or a mixture of neon with a small amount of one other

noble gas. Application of a DC voltage across opposed row and column electrodes

switches the gas at the pixel to a conducting discharge or plasma state, electrical

current flows through the gas, and the gas emits light. There are many variations of

the basic DC PDP.

A second type of PDP uses AC gas discharges (AC PDP). In these displays, the row and column electrodes are covered with insulating layers and are not directly

exposed to the gas as in the DC PDP. In addition, sustain electrodes are at or adjacent

to all pixels. The sustain electrodes are also covered with insulating layers. The

sustain electrodes apply an alternating current voltage known as the sustain voltage to

the entire PDP. The sustain voltage is generally a square wave voltage waveform at a

frequency of 25 kHz to 400 kHz. The sustain voltage magnitude is too low to cause

ionization of the gas, but it can sustain or re-initiate discharge in pixels in which

discharge has previously been initiated. There are many known configurations of AC

PDPs.

To adequately display motion, a display panel must display new images or

image frames at rates of about 60 Hz. Therefore, the total time permitted to display a

new image is about 16.7 msec. Plasma display panels are capable of achieving such

imaging rates at VGA or NTSC display addressabilities (i.e. , 480 and 525 lines,

respectively) with 6 to 8-bit grey scales. The electrical properties of the gas, including

forming and quenching the plasma or discharge, typically prevent plasma display

panels from achieving significantly higher display addressabilities. As a consequence,

plasma display panels have been incapable of rendering higher addressability (e.g. ,

SVGA), full color, gray scale motion displays without the use of complicated

electronics, such as dual scan addressing.

The pixel address time, which is the time to write the correct data into a

horizontal line, can be divided into two phases, the discharge initiation phase and the

plasma decay phase. The decay phase also includes the time needed to set-up the

proper wall charges required for conventional AC PDP operation. For typical PDPs

using mixtures of Ne-Xe or He-Xe, the pixel address time can be as long as about 3-6 μsec for each line in the display. For an 8-bit grey scale PDP display, each line is

addressed eight times during each image frame. Therefore, the minimum time required

to address the 480 lines in a VGA display is about 11.5 msec, over half of the 16.7

msec of the image frame period. Only about 5.2 msec is available for the sustain time,

which is when the display emits light. Because the sustain time is so limited, the

display brightness is just acceptable.

A significant part of pixel address time is the discharge initiation time for the

gas to switch between conducting and non-conducting states. The discharge initiation

time or turn-on time includes two distinct delays: the statistical delay and the initiation

delay. The statistical delay is the time needed for a random event to begin the

ionization process. The initiation delay is the time needed after the initial ionization

event for the avalanche process to create a plasma or discharge. Although both of

these times can be reduced by applying a higher firing voltage to turn on the pixel,

most PDPs must operate at as low a voltage as possible due to driver limitations.

Similarly, for typical PDPs using mixtures of Ne-Xe or He-Xe, the plasma

decay time, which is the second phase of the pixel address time, can be as long as 3-6

μsec. The processes that determine the length of this phase of the discharge are not

easily affected by controllable external parameters such as the applied voltage. Since,

for instance, these processes depend on the diffusion coefficients for the particles in

the gas, only gas composition or gross geometrical changes will have significant

effects. In most cases, other factors determine the geometry of the discharge cell and

thus the primary way to influence the plasma phase is through gas composition.

It will be appreciated that at display addressabilities greater than 480 lines, the

sustain time will be too short to provide adequate image brightness. Higher addressability displays for applications such as high definition television ("HDTV") or

computer workstations require 1000 lines or more. The minimum time to address a

1000 line, 256 gray level display using the method discussed above is about 22 msec,

which is greater than the image frame period. From this example, it is readily apparent

that there is a critical need to decrease pixel address time and therefore both the

discharge initiation phase as well as the plasma decay phase.

Gas mixtures of helium and other noble gases such as xenon or neon can

improve the effective decay time of helium. These mixtures are well-known as

Penning or quenching mixtures. These gas mixtures provide collision mechanisms

permitting metastable state de-excitation without ion-electron production. With these

mixtures, the gas changes from its conducting to its non-conducting state more

rapidly. In addition, the mixtures reduce the number of atoms or molecules that enter

into metastable states, reducing the total number of ions and electrons produced.

Unfortunately, quenching mixtures have several significant drawbacks. The

heavier noble gas in the mixtures greatly increases the sputtering rate, i.e. , the rate at

which the gas discharge drives material from the negative electrode (cathode) for DC

PDP or into the phosphors for AC PDPs, shortening the useful display lifetime. Often

the heavier gas must be present in the mixture in small but precise amounts to obtain

the quenching property. This is a serious disadvantage. In an operating display, gas

ions accelerate to and become buried in the electrodes or the phosphors, changing

relative gas concentration. Small changes in the concentration of the heavier gas may

cause the gas mixture to lose the quenching property. Therefore, successful use of

quenching mixtures may require a means of accurately preserving the appropriate gas

concentrations during display use. This probably requires a method of sensing gas concentrations and sourcing gas, further complicating the display.

Summary of the Invention

The present invention includes combinations of discharge gases for reducing

gas discharge switching times in gas discharge or plasma display panels, particularly

AC and DC PDPs of various configurations. A gas combination according to the

invention includes a conventional discharge gas or gas combination (e.g. , He-Xe) and

a discharge accelerant gas that reduces discharge initiation time and, additionally,

reduces the discharge turn-off or decay time in the addressing of gas discharge display

panels. Preferably, the discharge accelerant gas consists of hydrogen (H₂), but may

additionally include or consist of nitrogen (N₂). The combinations of the present

invention are effective over a broad range of concentrations of the discharge accelerant

gas. Relative concentrations of the discharge accelerant gas from about 0.01 % to

about 30% are effective. In contrast, conventional Penning or quenching mixtures that

are used to increase the effective decay rate of some discharge gases are highly

sensitive to the relative gas concentrations. Even slight variations in the relative gas

concentrations of a Penning mixture (e.g. , as little as about 3 percent), such as those

arising from incidental embedding of Penning mixture constituents into containment

walls, significantly degrade the quenching effectiveness of the mixture.

Moreover, the discharge accelerant gas or gases of this invention are of low

atomic weight relative to conventional Penning mixture constituents (e.g., xenon).

Such a low weight discharge accelerant gas decreases cathode sputtering and increases

display lifetime in comparison to conventional Penning mixture constituents.

The foregoing and other objects, features, and advantages of the invention will

become more apparent from the following detailed description of a preferred embodiment which proceeds with reference to the accompanying drawings.

Brief Description of the Drawings

Fig. 1 is a simplified fragmentary side sectional view showing one pixel of an

exemplary AC plasma display panel.

Fig. 2 is a timing representation of an address display period separated sub-

field (ADS) method of operating the AC plasma display panel of Fig. 1.

Fig. 3 is a timing diagram illustrating the address display period separated sub-

field method of Fig. 2.

Detailed Description of Preferred Embodiment

FIG. 1 is a simplified fragmentary side sectional view showing one pixel of a

conventional AC plasma display panel (AC PDP) 10 that employs a discharge gas

mixture of the present invention. It will be appreciated that PDP 10 would include a

large number of pixels, typically arranged in rows and columns, and preferably is of

moderate addressability (e.g. , VGA or NTSC) or high addressability (e.g. , SVGA or

HDTV). While described with reference to AC PDP 10 as a particular exemplary

plasma display panel, the present invention is applicable to and usable with other types

or configurations of PDPs, including other types of AC PDPs and various DC PDPs.

PDP 10 has two flat nonconductive substrates 12 and 14, at least one of which

is transparent. One set of address electrodes 16 (either rows or columns, only one

shown) is formed on substrate 12. Insulating spacers 18 are situated adjacent to

electrode 16 and serve to space apart substrates 12 and 14 and to confine the gas

discharge. A phosphor layer 20 is deposited on and between the insulating spacers 18.

Substrate 14 supports two sets of electrodes 22 and 24 that typically are

orthogonal to electrodes 16 on substrate 12. In this view electrode 24 would be behind electrode 22. Electrode 22 is a sustain voltage electrode, and electrode 24 is a

write/sustain electrode. On top of both of these electrodes are auxiliary electrodes 23

and 25. Electrodes 22 and 24 are typically transparent electrodes, and therefore have

difficulties is carrying high currents due to their high resistivity. Auxiliary electrodes

23 and 25 are typically not transparent and therefore have a much lower resistance.

Insulating layer 26 covers electrodes 22, 23, 24, and 25 and is in turn covered by

another protective insulating layer 28. The separation formed between substrates 12

and 14 by spacers 18 forms a cavity 30 that contains a discharge gas according to the

present invention.

In a display according to the present invention, the cavity 30 is filled with an

improved discharge gas combination. The discharge gas combination has at least one

primary discharge gas and at least one discharge accelerant gas. The primary

discharge gas preferably contains helium, neon, argon, xenon, or krypton, or a

combination of these gases, but other discharge gases are known. The discharge

accelerant gas is preferably hydrogen or nitrogen or a combination thereof.

In a preferred embodiment, the primary discharge gas is a combination of

between 80 and 99.9 percent helium and 20 and 0.1 percent xenon, respectively. The

discharge accelerant gas is hydrogen, which is effective over a wide range of relative

combinations with the primary discharge gas. Preferably, the gases are combined in

proportions from a virtually trace amount of 0.01 percent discharge accelerant gas to

99.99 percent primary discharge gas to a major component amount of about 30 percent

discharge accelerant gas to 70 percent primary discharge gas.

The discharge accelerant gas speeds the initiation and the decay of the

discharge or plasma generated at each pixel within PDP 10. The discharge initiation time is the period during which the discharge gas changes from its non-conducting

state to its conducting state, and the discharge decay time is the period during which

the discharge gas changes from its conducting state to its non-conducting state and the

appropriate wall charge is set. The combination of the discharge initiation time and

the discharge decay time, which is the pixel address time, of conventional PDPs

typically limit the active imaging periods in PDPs to such an extent that the nominal

60 Hz image frame rate necessary for full motion video can be achieved up to VGA

and NTSC addressabilities only.

Speeding the pixel address time provides PDP 10 with longer active imaging

periods, which are referred to as sustain periods for AC PDPs, therefore allowing

PDP 10 to operate at addressabilities above VGA and NTSC (e.g. , SVGA and HDTV

resolutions) for a given grey scale range (e.g. , 8-bits). In addition or as alternatives to

the higher display addressabilities, the longer active imaging periods can provide

increased image brightness, contrast, or grey scale range. For example, grey scale

ranges of more than 8-bits can be used with VGA, NTSC, or higher addressabilities.

Fig. 2 is a timing representation of an address display period separated sub-

field (ADS) method of operating AC PDP 10 to illustrate benefits of this invention

with respect to a conventional VGA display of 480 lines. In the ADS method of

displaying a gray scale image, the image frame period of an AC PDP is divided into

several sub-fields. For 256 gray levels, the period is divided into 8 sub-fields SF0-

SF7. Each sub-field is further divided into a plasma- or discharge-generating address

period and an active imaging sustain period.

The sustain periods of sub-fields SF0-SF7 have relative durations that are of

the binary orders 2° through 2⁷, respectively. Because image brightness is proportional to the length of the sustain period, the relative durations of the sub-field

sustain periods permit display of 256 gray levels. The sub-field address period relates

to the discharge initiation and decay rates and is therefore of generally the same

duration for each sub-field.

Fig. 3 is a timing diagram illustrating the addressing and sustain signals used

within one of the eight sub-fields in the ADS method of Fig. 2. The writing sequence

for each sub-field includes erasing all pixels (step 1), writing all pixels (step 2),

erasing all pixels (step 3), and writing the sub-field data line-by-line (step 4).

In the writing of the sub-field image data, all the pixels in a line (e.g. , row) to

be activated or illuminated during the sub-field receive an address pulse on the address

electrode 16 while the sustain/write electrode 24 of the line receives a scan pulse.

Each line in PDP 10 is similarly addressed during the address period of the sub-field.

The combination of the address pulses on electrodes 16 and the scan pulses on

sustain/write electrodes 24 initiate low-current, low luminance discharges at the

selected pixels after a discharge initiation delay period.

After all the lines in PDP 10 are addressed, they receive sustain pulses

alternately on sustain electrodes 22 and 24 for a sustain period corresponding to the

binary order of the sub-field. The sustain pulses initiate at the selected pixels high-

current, luminant discharges that emit ultraviolet radiation. Phosphor 20 absorbs

some of this radiation and converts it into visible light. Before addressing PDP 10 for

the next sub-field, the discharge gas must decay into its non-conducting state.

In conventional PDPs having a Penning or quenching gas mixture of neon and

xenon or helium and xenon, for example, the pixel address time of each line of each

sub-field can be as much as 3-6 μsec. Therefore, the minimum time required to write in eight sub-fields the 480 lines in a conventional VGA PDP display is about 11.5

msec, which is a significant fraction of the 16.7 msec image frame period. Only about

5.2 msec is available for the active imaging sustain period, which is just adequate for

VGA displays. At higher display addressabilities, however, the addressing period

required by the 3-6 μsec pixel address time requires unacceptable portions of or more

than the 16.7 msec image frame period.

A preferred gas combination of between 0.01 and 30 percent discharge

accelerant gas (e.g., hydrogen) and between 99.99 and 70 percent primary discharge

gas has a discharge initiation time of less than 200 nsec, which is significantly less

than the conventional discharge initiation time of 1-3 μsec which limits display

resolution capabilities of PDPs. Moreover, the preferred gas combination of the

invention also reduces the discharge decay time of about 1-3 μsec by about a factor of

two, which further reduces discharge time limitations on display resolution capabilities

of PDPs.

In addition to providing any of increased addressability, increased brightness,

increased grey scale range, increased contrast, and decreased discharge initiation and

decay times, the gas combinations of the present invention can provide reduced

discharge operating voltage. Reduced drive voltages are desirable because they allow

simplification of the discharge-generating driver electronics, improve the safety of

PDPs, and increase the operational life of PDPs.

The discharge decay time or turn-off time depends on the decay rates of

metastable gas atoms or molecules in the discharge. The metastable states are charge

neutral atomic or molecular energy states for which de-excitation to less energetic

states occurs at relatively slow rates. Metastable states decay predominantly through collisions with other neutral atoms or molecules or with the surfaces confining the gas.

Collisions with other neutral atoms or molecules produce a neutral atom, a positively

charged ion, and an electron. The charged ion and electron keep the gas in an

electrically conducting state, increasing turn-off time.

Conventional methods for minimizing the effects of metastable states include

decreasing the diffusion time to the confining walls, increasing the collision rate, or

providing a collision mechanism producing fewer charged particles. The reduced

charge decay time provided by the discharge accelerant gas indicates reduced effects of

metastable states. This reduction in metastable state effects is achieved without the

difficulties and complications of conventional methods.

The embodiment of FIG. 1 shows a single phosphor layer 20. As is known,

PDPs can render full color images using three or more phosphors. Generally each

pixel is sub-divided into red, green, and blue sub-pixels and appropriate phosphors are

deposited at each sub-pixel. Each sub-pixel is separately addressed to produce the red,

green, or blue intensity of the image to be displayed.

The gas mixtures of this invention are applicable to and compatible with

virtually all PDPs, including AC PDPs and DC PDPs. There are many known AC

PDP configurations that are alternatives to that of AC PDP 10 described hereinabove.

One variant of the PDP is the AC refresh PDP, in which the sustain frequency is very

high, increasing light output.

One type of DC PDP has simple crossed row and column electrodes spaced

apart with dielectric barriers, the barriers serving both to space the electrodes and to

confine the discharge to a single pixel. The space between the electrodes is filled with

a dischargeable gas, usually neon or a mixture of neon with a small amount of one other noble gas. Application of a DC voltage to a row and column electrodes switches

the gas at the pixel to a conducting state, electrical current flows through the gas, and

the gas emits light.

Frequently such DC PDPs have additional trigger electrodes. A sufficiently

large voltage applied to the trigger electrodes ionizes the gas mixture in the

neighborhood of a large number of pixels, reducing the voltage required on the row

and column electrodes to initiate the gas discharge and turn the pixel to its fully

conducting state. Other variants of the DC PDP include photoluminescent PDPs in

which the gas discharge produces ultraviolet light for conversion to the visible by a

phosphor.

Having described and illustrated the principles of our invention with reference

to a preferred embodiment thereof, it will be apparent that the invention can be

modified in arrangement and detail without departing from such principles. In view of

the many possible embodiments to which the principles may be put, it should be

recognized that the detailed embodiment is illustrative only and should not be taken as

limiting the scope of our invention. Accordingly, we claim as our invention all such

modifications as may come within the scope and spirit of the following claims and

equivalents thereto.

Claims

We claim:

1. In a gas discharge display panel having a discharge gas that is switched

between substantially conducting and substantially non-conducting states, a discharge

gas combination, comprising:

a primary discharge gas of one or more constituent gases having a primary gas discharge initiation time; and

a discharge accelerant gas that in combination with the primary gas has a

combined gas discharge initiation time that is less than the primary gas discharge

initiation time with general insensitivity to the relative proportions of the primary

discharge gas and the discharge accelerant gas.

2. The gas combination of claim 1 wherein the discharge accelerant gas

includes nitrogen or hydrogen.

3. The gas combination of claim 1 wherein the discharge accelerant gas

provides the lesser combined gas discharge initiation time over a range of more than

an order of magnitude of relative proportions to the primary discharge gas.

4. The gas combination of claim 3 wherein the discharge accelerant gas and

the primary discharge gas are combined in proportions by volume of X and 1-X,

respectively, where X is between about 0.01 and 0.3.

5. The gas combination of claim 1 wherein the primary discharge gas includes

one or more of the following gases: helium, neon, xenon, argon, krypton.

6. The gas combination of claim 1 wherein the discharge accelerant gas is

hydrogen.

7. The gas combination of claim 6 wherein the discharge accelerant gas and

the primary discharge gas are combined in proportions by volume of X and 1-X, respectively, where X is between about 0.01 and 0.3.

8. The gas combination of claim 7 wherein the primary discharge gas includes

one or more of the following gases: helium, neon, xenon, argon, krypton.

9. The gas combination of claim 1 wherein the discharge accelerant gas is

nitrogen.

10. The gas combination of claim 9 wherein the discharge accelerant gas and

the primary discharge gas are combined in proportions by volume of X and 1-X,

respectively, where X is between about 0.01 and 0.3.

11. The gas combination of claim 10 wherein the primary discharge gas

includes one or more of the following gases: helium, neon, xenon, argon, krypton.

12. In a gas discharge display panel having a discharge gas that is switched

between substantially conducting and substantially non-conducting states, the

improvement comprising hydrogen in the discharge gas.

13. The gas discharge display panel of claim 12 configured as an AC plasma

display panel or a DC plasma display panel.

14. The gas discharge display panel of claim 12 further comprising a display

resolution of at least 480 lines and a grey scale range of more than 8 bits.

15. The gas discharge display panel of claim 12 further comprising a grey

scale range of at least 8 bits and a display resolution of more than 525 lines.

16. The gas discharge display panel of claim 12 wherein the discharge gas

further includes a primary discharge gas combined with the hydrogen in proportions

by volume of 1-X and X, respectively, where X is between about 0.01 and 0.3.

17. The gas discharge display panel of claim 16 wherein the primary discharge

gas includes one or more of the following gases: helium, neon, xenon, argon, krypton.

18. The gas discharge display panel of claim 11 wherein the discharge gas

further includes one or more of the following gases: helium, neon, xenon, argon,

krypton.

19. In a gas discharge display panel having a discharge gas that is switched

between substantially conducting and substantially non-conducting states, the

improvement comprising nitrogen in the discharge gas.

20. The gas discharge display panel of claim 19 configured as an AC plasma

display panel or a DC plasma display panel.

21. The gas discharge display panel of claim 19 further comprising a display

resolution of at least 480 lines and a grey scale range of more than 8 bits.

22. The gas discharge display panel of claim 19 further comprising a grey

scale range of at least 8 bits and a display resolution of more than 525 lines.

23. The gas discharge display panel of claim 19 wherein the discharge gas

by volume of 1-X and X, respectively, where X is between about 0.01 and 0.3.

24. The gas discharge display panel of claim 23 wherein the primary discharge

25. The gas discharge display panel of claim 19 wherein the discharge gas

krypton.

26. In a gas discharge display panel having a discharge gas that is switched

gas combination, comprising:

a primary discharge gas of one or more constituent gases having a primary gas discharge voltage; and

a discharge accelerant gas that in combination with the primary gas has a

combined gas discharge voltage that is less than the primary gas discharge voltage.

27. A discharge gas combination for a gas discharge display panel wherein

the discharge gas combination is switched between substantially conducting and

substantially non-conducting states, the discharge gas combination, comprising:

a primary discharge gas including one or more of the following gases:

helium, neon, xenon, argon, krypton; and

a discharge accelerant gas comprising nitrogen gas; and

wherein the primary discharge gas and the discharge accelerant gas are

combined in proportions by volume of X and 1-X, respectively, where X is between

about 0.10 and 0.3.

28. In a gas discharge display panel having a discharge gas that is switched

between substantially conducting and substantially non-conducting states, the

improvement comprising nitrogen in the discharge gas in a proportion of between

about 0.1 and 0.3.

29. A discharge gas combination for a gas discharge display panel wherein

the discharge gas combination is switched between substantially conducting and

substantially non-conducting states, the discharge gas combination comprising:

a primary discharge gas including one or more of the following gases:

helium, neon, xenon, argon, krypton; and a discharge accelerant gas comprising hydrogen gas.

30. The discharge gas combination of claim 29 wherein the discharge

accelerant gas and the primary discharge gas are combined in proportion by volume of

X and 1-X, respectively, where X is between about 0.01 and 0.3.

31. A plasma display panel wherein a discharge gas is switched between

substantially conducting and substantially non-conducting states, comprising:

a first non-conducting plate;

a second non-conducting plate, parallel to the first plate and defining a cavity

therebetween;

a set of row electrodes, supported by the first plate and facing the cavity;

a set of column electrodes, supported by the second plate and facing the

cavity;

a discharge gas in the cavity, the discharge gas comprising a primary

discharge gas including at least one of the following gases: helium, neon, xenon,

argon, krypton; and a discharge accelerant gas comprising nitrogen gas; and wherein

the primary discharge gas and the discharge accelerant gas are combined in

proportions by volume of X and 1-X, respectively, where X is between about 0.10 and

0.3.

32. A plasma display panel wherein a discharge gas is switched between

substantially conducting and substantially non-conducting states, comprising:

a first plate; a second plate, parallel to the first plate and defining a cavity therebetween;

a set of row electrodes, supported by the first plate and facing the cavity;

a set of column electrodes, supported by the second plate and facing the

cavity;

a discharge gas in the cavity, the discharge gas comprising a primary

argon, krypton; and hydrogen.

33. The plasma display panel according to claim 32, wherein the primary

discharge gas and hydrogen are combined in proportions by volume of 1-X and X,

respectively, where X is between about 0.01 and 0.3.