JPH07192631A - Gas discharge type display device - Google Patents

Abstract

PURPOSE:To provide a gas discharge type display device of long life excellent in sputter resistance with a small fluctuation of discharge voltage by giving a cathode having a wide discharge surface from the begining of starting a discharge to improve also its spread without even dispersion in the discharge voltage. CONSTITUTION:A gas discharge type display device comprises front/back glass plates l, 3 held to be opposed to each other by a partition 5, first/second electrode wires 2, 4 respectively provided in internal surfaces of the front/back glass plates l, 3 and a display electrode body 7 provided in the internal surface of the back glass plate 3 so as to be opposed to the first electrode wire 2 and electrically connected to the second electrode wire 4 through a resistor unit 8. By applying voltage across the first/second electrode wires 2, 4, a gas discharge is generated between the first electrode wire 2 and the display electrode body 7. A cathode 7a in a surface part of the display electrode body 7 is formed of cathode material mainly composed of aluminum granule consisting of flake- shaped aluminum grain.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas discharge type display device for displaying characters and images using gas discharge.

[0002]

2. Description of the Related Art In recent years, a gas discharge type display device (plasma display panel, hereinafter referred to as PDP) has been used as a flat type display device for an information terminal such as a portable computer, and has a clear display and a wide viewing angle. (The viewing angle is wider than that of liquid crystal panels), and its application fields are expanding.

Further, as television receivers have become larger and larger, projection-type televisions having a projection cathode-ray tube or a liquid crystal panel have been commercialized to deal with them, but problems still remain in the brightness of the screen and the size of the device. ing.

On the other hand, the PDP has recently been remarkably advanced in its colorization technology, and is in the spotlight as a display device capable of greatly reducing the depth in place of a cathode ray tube. , Faithful color reproduction and improvement of brightness and life are expected.

Hereinafter, a conventional memory drive type DC PD
An example of P will be described with reference to the drawings.

FIG. 6 shows a conventional memory drive type DC type PD.
It is sectional drawing which shows P. As shown in FIG. 6, in a conventional memory drive type DC PDP, a front glass plate 5 is used.
A first electrode wire 52 extending in the left-right direction formed on the first electrode;
The second electrode wires 54 formed in the back glass plate 53 and extending in the front-rear direction are opposed to each other across the partition wall 55 at positions orthogonal to each other, and the discharge cells 56 are formed at the intersections thereof. A discharge gas mainly containing a rare gas is enclosed in the. A display electrode body 57 is provided on the rear glass plate 53 side of the discharge cell 56, and a cathode 57a is formed on the upper layer portion of the display electrode body 57. The display electrode body 57 is connected to the second electrode wire 54 by the resistor 58,
The display electrode body 57 and the first electrode wire 52 form a pair of discharge electrodes. The rear glass plate 53 is coated with a phosphor 59 except for the portion where the display electrode body 57 is provided.

In the memory drive type DC PDP having the above-described structure, when a voltage is applied between the first electrode line 52 and the second electrode line 54, the first electrode line 52 and the display electrode body are A display discharge is generated between the display and 57. Once the discharge is caused by the application of the voltage, the discharge can be restarted at a voltage lower than the voltage for a certain period even when the voltage is removed.

By the way, in the basic principle of the light emission mechanism of the gas discharge type display device, the properties and characteristics of materials such as an electrode body, a resistor, an insulator, an enclosed gas and a phosphor constituting a discharge panel are the discharge voltage and the display. Naturally, the properties are greatly affected, and research on these constituent materials has been continued.

In FIG. 6, the cathode 57a formed in the upper layer portion of the display electrode body 57 is conventionally made of a metal material such as nickel. As another example, there is known one composed of a substance having a large secondary electron emission coefficient, such as lanthanum boride, titanium carbide, tantalum carbide, yttrium oxide or barium oxide (Japanese Patent Laid-Open No. 4-2.
72635).

[0010]

However, in the conventional memory drive type DC PDP, there is a problem that the discharge voltage fluctuates when used for a long time. This fluctuation of the discharge voltage has a great influence on the memory function. That is, when a current is passed through the display electrode body 57 through the resistor 58, the discharge current increases as the discharge voltage decreases, and the DC type P
The brightness of DP fluctuates. If this occurs in a part of the panel, it will appear on the screen as a burn-in pattern. Further, when the discharge memory 56 is caused to perform the memory function of discharge with reference to the discharge voltage, if the reference discharge voltage changes, the memory function cannot be normally maintained.

As a solution to the problem of the conventional memory drive type DC PDP, it is considered to use an oxide conductor instead of a metal material such as nickel or aluminum which has been conventionally used as a cathode material. To be done.

However, although the rate of change of the discharge voltage with respect to the discharge time is reduced by using the oxide conductor, the discharge is concentrated on a part of the cathode surface, and the increase of the sputtering or the discharge voltage due to the increase of the current density. There is a problem in that it causes an increase in Therefore, the oxide conductor material originally used for extending the life and stabilizing the discharge voltage, on the contrary, shortens the life and causes a change in the discharge voltage.

An object of the present invention is to solve the above-mentioned problems all at once, and to provide a gas discharge type display device which has a small variation in discharge voltage, is excellent in spatter resistance and has a long life.

[0014]

In order to achieve the above object, as a result of further consideration of the cause of the fluctuation of the discharge voltage, which is a problem of the conventional memory drive type DC PDP,
The electrode material used as a cathode material, which has been found to be as described below, is used as a paste after being crushed into fine particles. FIG. 7 shows the display electrode body 57 by printing this paste.
FIG. 7 is a schematic enlarged view of the cathode 57a formed in the upper layer portion of FIG. 7. The surface of the completed cathode 57a is shown in FIG.
As shown in FIG. 5, it is formed from an aggregate of particles 61 of the electrode body material. When the discharge 62 is started in this state, the discharge 62
Starts from a part of each particle 61 of the electrode body material and gradually widens the discharge surface. Changes in the discharge state over time are shown in FIGS. 8 (a), 8 (b) and 8 (c).

The reason why the entire surface of the particles of the electrode body material is not discharged at the time of starting the discharge is that the surface of each particle is contaminated during the heating or firing process during the production of the electrode body, or the surface of the material is oxidized to deteriorate. This is because

As shown in FIG. 8A, once the discharge 62
When the start occurs, the deteriorated portion of the discharge surface 63 of the particles 61 of the electrode body material is removed by sputtering, and the area of the discharge surface 63 increases as shown in FIG. 8B. And
The surface of the cathode 57a is transformed into a series of the flat discharge surface 13 which is not an aggregate of the particles 61 of the electrode body material and the adherend 64 of the electrode body material scraped by sputtering, and finally, as shown in FIG. As shown in (c), the discharge 62 spreads over the entire surface of the cathode 57a.

As a basic phenomenon of gas discharge, the discharge voltage depends only on the current density per unit surface area unless the cathode material changes its basic characteristics by discharge, and if the discharge current is constant and the area of the discharge surface increases, The discharge voltage drops.
That is, the fluctuation of the discharge voltage depends on the discharge area. Therefore, the discharge voltage fluctuates and drops in the course of the above series of phenomena.

As described above, the present invention is based on the finding that the change in the discharge voltage is related to the change in the discharge area depending on the cathode material.

Specifically, the solution means taken by the invention of claim 1 is the first and second means, which are held by the partition wall so as to face each other.
Substrate, first and second electrode lines provided on the first and second substrates, respectively, and an electrode body provided on the second substrate and electrically connected to the second electrode line. With and
A gas discharge type display device for performing display by using gas discharge generated between the first electrode line and the electrode body by applying a voltage between the first and second electrode lines, The electrode body is configured such that at least a surface layer of the electrode body is provided with a cathode formed of a cathode material whose main component is conductive powder made of scale-shaped conductive particles.

The invention of claim 2 is, specifically, claim 1
In addition to the configuration of the invention, the remaining portion of the electrode body excluding the portion where the cathode is formed is made of a conductive material having an electric resistivity smaller than that of the cathode material.

The invention of claim 3 is specifically, claim 1.
Alternatively, the above-mentioned conductive powder is an aluminum powder composed of scale-shaped aluminum particles, in addition to the structure of the invention of item 2.

[0022]

According to the structure of the invention of claim 1, at least the surface layer of the cathode on the surface portion of the electrode body is mainly composed of conductive powder made of scale-shaped conductive particles. Therefore, the substantial surface area of the cathode material that contributes to the discharge becomes significantly large, unlike the conventional spherical particles, and a large discharge area can be obtained from the beginning of the discharge. As a result, the width of expansion of the discharge area over time can be reduced,
It is possible to suppress a decrease in discharge voltage.

Further, since the scale-like conductive particles have a smaller thickness than the conventional spherical particles, they form a layer when forming the cathode, and the cathode has very few irregularities on the surface and is uniform without coarse and dense. Will be things. Therefore, the discharge voltage changes extremely stably, and it is possible to prevent an abnormal fluctuation phenomenon of the discharge voltage.

Further, since the discharge spread is good from the beginning and the discharge current is not concentrated on a specific portion of the discharge surface, spatter can be reduced. As a result, scattering of pollutants due to sputtering can be reduced, and, for example, contamination of the glass surface or the surface of the phosphor can be suppressed. For this reason, it is possible to suppress the deterioration of the luminance, and it is possible to extend the life of the gas discharge display device.

According to the structure of the invention of claim 2, the cathode and the second
It is possible to keep good electrical continuity with the electrode wire of.

With the structure of the third aspect of the present invention, the cathode as described above can be realized by aluminum powder made of scale-shaped aluminum particles.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Here, as a gas discharge type display device according to an embodiment of the present invention, a memory drive type direct current type P
An example of DP will be described.

FIG. 1 shows a gas discharge type display device according to the above embodiment. As shown in FIG. 1, in the gas discharge display device of the present embodiment, a group of first electrode lines 2 formed in a front glass plate 1 as a first substrate and extending in the left-right direction, and a second electrode line 2 A group of second electrode wires 4 extending in the front-rear direction formed on a back glass plate 3 as a substrate face each other at a position orthogonal to each other with a partition wall 5 sandwiched therebetween, and a large number of discharge cells 6 are arranged in a matrix at intersections thereof. Is formed in. The front glass plate 1 and the rear glass plate 3 combined together are sealed with low melting point glass or the like around the periphery thereof, and a discharge gas mainly containing a rare gas is sealed inside.

A display electrode body 7 is provided on the back glass plate 3 side of each discharge cell 6, and the display electrode body 7 is a resistor body 8.
Is connected to the second electrode line 4, and the display electrode body 7 and the first electrode line 2 form a pair of discharge electrodes. Therefore, the display electrode body 7 serves as a cathode or an anode of the discharge electrode, and the second electrode wire 4 functions as a cathode bus bar or an anode bus bar with respect to the display electrode body 7. The back glass plate 3 is coated with a phosphor 9 except for the portion where the display electrode body 7 is provided. The front glass plate 1 is transparent, and the surface of the phosphor 9 can be directly observed through the discharge cell 6 except for the portion shielded by the first electrode wire 2. Each of the first electrode line 2, the second electrode line 4, the display electrode body 7,
The resistor 8, the phosphor 9, the partition wall 5, and the like are formed on a glass plate by using a thick film printing technique, and can be manufactured at an extremely low cost.

Next, the operation of the gas discharge type display device configured as described above will be described. In FIG. 1, when a voltage is applied to one set arbitrarily selected from the combination of the first electrode wire 2 and the second electrode wire 4, the first electrode wire 2 is discharged in the discharge cell 6 at the intersection position. A display discharge is generated between the display electrode body 7 and the display electrode body 7. The voltage at this time is called a write voltage. By sequentially applying the writing voltage through the plurality of display electrode bodies 7, discharge is generated in the discharge cells 6 arranged in the entire display device, and light is emitted to display a desired pattern. In the case of color display, for example, xenon is mainly used as a discharge gas, and ultraviolet rays emitted by this are used to excite the phosphor 9.

In the memory drive type DC PDP, charged particles remain in the discharge cell 6 when discharge is once caused by the application of the write voltage, so that the write voltage is removed for a certain period (normally). The discharge can be restarted at a voltage (Vm) lower than the initial writing voltage (Vw) for several microseconds. The memory driving method utilizes this phenomenon, and therefore the stability of the discharge voltage is extremely important in this method. If a voltage pulse of about Vm is continuously applied within the fixed period,
Continuous display emission occurs. Since the light emission of the phosphor 9 is attenuated with time, there is also an effect of improving the display brightness by excitation with a continuous pulse voltage utilizing the memory effect. A display luminance of 100 cd / m ² or more is measured by this method, which satisfies the value required for a television display device.

Here, the difference between the gas discharge type display device of this embodiment and the conventional example will be described.

FIG. 2 shows a part of the structure of the gas discharge type display device according to this embodiment. As shown in FIG. 2, the display electrode body 7 is composed of a cathode 7a formed on the surface thereof and a display electrode 7b which is a portion excluding the cathode 7a.

The present embodiment is different from the conventional example shown in FIG. 6 in the structure of the display electrode body 7, and is particularly characterized in the cathode material contained in the cathode 7a as a main component.

More specifically, as shown in FIG. 3, instead of the aluminum powder composed of spherical aluminum particles (hereinafter referred to as spherical particle aluminum powder) which has been conventionally used as a cathode material, a scaly shape, that is, It is characterized in that an aluminum powder 17 composed of flake-shaped aluminum particles (hereinafter referred to as flake-shaped aluminum powder) is used. It is shown in (Table 1) in order to compare the characteristics of the cathode 7a according to the present embodiment, which is made of aluminum powder of flake particles, and the conventional cathode made of aluminum powder of spherical particles.

[0036]

[Table 1]

However, if aluminum powder of flake particles is pasted and printed to form the entire display electrode body 7, the electric resistance of the display electrode body 7 increases, and electrical conduction cannot be obtained as it is. Therefore,
In the present embodiment, as shown in FIG. 3, when the aluminum powder 17 of flake particles is used as a cathode material in the display electrode body 7, the display electrode body 7 is electrically connected to the second electrode wire 4 in order to achieve electrical connection. The aluminum powder 18 having spherical particles was used as 7b, and the cathode 7a was formed on the aluminum powder 17 having flake particles.

In forming the display electrode 7b and the cathode 7a, first, 10 to 50% by weight of glass powder is added to spherical aluminum powder 18, organic solvent and resin components are added as a binder, and the mixture is sufficiently kneaded to form a paste. To obtain a display electrode paste. Similarly, 1 to 50% by weight of glass powder is added to the aluminum powder 17 of flake particles, and the mixture is kneaded with an organic solvent and a resin component to obtain a cathode paste. Next, on the rear glass plate 3, a display electrode paste is linearly printed with a thickness of 10 to 50 μm so as to be connected to the second electrode wire 4 via the resistor 8. Next, a cathode paste of 10 to 50 μm is formed on top of it.
Print with the thickness of. In this way, the rear glass plate 3 having the display electrode 7b and the cathode 7a patterned is placed in a baking furnace and baked at a temperature of 500 to 600 ° C. to form the display electrode body 7. Flake-shaped aluminum powder 1
The cathode 7a of 7 shrinks due to firing, so that the display electrode 7
It is formed thinner than the thickness of b.

A comparative test of the characteristics of the gas discharge type display device of the present example having the display electrode body 7 as described above and the conventional gas discharge type display device was conducted. Here, both of them were filled with 200 Torr (26.6 kPascal) of a He / Xe mixed gas containing 5% of Xe, and a discharge current of 100 μA was applied to each unit cell to perform discharge lighting. The sample used in the comparison test this time has a gas pressure reduced to about 60% as compared with the gas discharge display device as a product. Generally, in a display panel using gas discharge, when the gas pressure is lowered, the sputtering of electrodes becomes more intense and the characteristics (discharge voltage, lowering of luminance, etc.) are deteriorated at an accelerated rate. The gas pressure is 6 like this time
It has been confirmed that the rate of deterioration becomes 10 times or more when it is reduced to about 0%.

FIG. 4 is a characteristic diagram showing the relationship between the discharge voltage and the discharge time of the gas discharge display device of this embodiment and the conventional gas discharge display device. This characteristic diagram is obtained as a result of selecting five discharge cells from each of the gas discharge type display device of the present example and the conventional example and measuring the discharge voltage thereof over time. In addition, in order to stabilize the discharge, the display panel generally performs a so-called aging in the initial stage of lighting by passing a larger current than that during normal use, but in this comparative test, the stability of each discharge cell is also evaluated. The measurement was performed without this aging.

In FIG. 4, the solid line shows the characteristic curve of the discharge voltage according to this embodiment, and the broken line shows the characteristic curve of the discharge voltage according to the conventional example. As is clear from FIG. 4, in the conventional example in which the spherical aluminum powder is used as the cathode, the discharge voltage varies greatly among the discharge cells. This is because there are variations in the discharge spread in the initial stage of lighting. Compared with the conventional example, in the present example in which the aluminum powder of flake particles was used for the cathode, the discharge voltage was lower from the initial lighting. This indicates that the discharge surface has spread from the beginning of lighting.

Further, as the discharge time elapses, the conventional example shows a very unstable state in which the discharge voltage fluctuates in a complicated manner. On the other hand, in the present embodiment, there is little variation between the discharge voltages of the respective discharge cells, there is little variation with the passage of time, and moreover, no specific behavior is observed in the variation for each discharge cell. The abnormal fluctuation phenomenon of the discharge voltage in the conventional example is caused by expansion or contraction of the discharge surface due to sputtering, but in the present embodiment having a wide discharge surface from the beginning, such a phenomenon does not occur, Therefore, the discharge voltage also changes extremely stably.

FIG. 5 is a characteristic diagram showing the relationship between the relative luminance and the discharge time of the gas discharge display device of this embodiment and the conventional gas discharge display device.

In FIG. 5, the solid line shows the characteristic curve of relative luminance according to the present embodiment, and the broken line shows the characteristic curve of relative luminance according to the conventional example. The deterioration in brightness occurs because the front glass plate and the surface of the phosphor are contaminated with scattered substances due to sputtering of the cathode material. Therefore, FIG. 5 shows that the conventional cathode made of spherical aluminum powder has many scattering of pollutants due to discharge sputtering.

The deterioration of the brightness is the most important factor for determining the life of the gas discharge type display device, and assuming that the time when the brightness decreases to half the initial value is the life of the device, the gas discharge type display device of this embodiment is used. According to the measurement result shown in FIG. 5, the display device has a life of about 2.8 times that of the conventional example. That is, in the aluminum powder of the flake-like particles used for the cathode of the present example, the spread of the discharge surface was good from the beginning, the discharge current was not concentrated on a specific part of the discharge surface, and the sputtering was also reduced. It contributes to longer life.

As described above, according to this embodiment, the cathode 7a containing aluminum powder of flake particles as a main component is formed on the surface of the display electrode body 7 formed on the back glass plate 3.
Since the discharge surface is wide, the discharge surface is wide from the beginning of discharge, therefore the discharge spread is good, there is no variation in the discharge voltage, and there is little fluctuation in the discharge voltage over time. A display device can be obtained.

In this embodiment, in the display electrode body 7, the example in which the cathode 7a containing aluminum powder of flake particles as a main component is provided on the display electrode 7b has been described. It suffices that the surface layer is composed mainly of aluminum powder of flake particles, the display electrode 7b and the cathode 7a are of the same quality, and the same effect can be obtained even if they are formed at the same time.

Further, in the present embodiment, the example in which the cathode 7a is formed on the rear glass plate 3 has been described, but it is obvious that the same effect can be obtained by forming the cathode on the front glass plate 1. Don't wait

[0049]

As described above, according to the gas discharge display device of the first aspect of the invention, at least the surface layer of the cathode on the surface of the electrode body is made of conductive powder having scale-shaped conductive particles. Since it is composed mainly of, it is possible to obtain a large discharge area from the beginning of the discharge. As a result, the width of expansion of the discharge area with the passage of time can be reduced, so that it is possible to suppress a decrease in the discharge voltage. Further, since the cathode has very few irregularities on its surface and becomes a homogeneous one without sparse and dense, the discharge voltage changes extremely stably and an abnormal variation phenomenon of the discharge voltage can be prevented. Further, the discharge spread is good from the beginning, and the discharge current is not concentrated on a specific portion of the discharge surface, so that the spatter can be reduced. Therefore, it is possible to suppress the deterioration of the brightness, and it is possible to extend the life of the gas discharge display device.

Further, since spatter can be reduced and scattering of contaminants due to spatter can be suppressed, deterioration of brightness can be suppressed and the life of the display device can be extended.

According to the gas discharge type display device of the second aspect of the present invention, good electrical continuity between the cathode and the second electrode line can be maintained.

Further, according to the gas discharge type display device of the third aspect of the invention, the cathode as described above can be realized by aluminum powder made of scale-shaped aluminum particles.

As described above, according to the present invention, it is possible to provide a gas discharge type display device which has a small fluctuation in discharge voltage, excellent spatter resistance and a long life.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing a gas discharge display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a main part of the gas discharge type display device according to the above embodiment.

FIG. 3 is a schematic view showing a display electrode body of the gas discharge type display device according to the above embodiment.

FIG. 4 is a characteristic diagram showing the relationship between the discharge voltage and the discharge time of the gas discharge type display device according to the above-mentioned embodiment and the conventional gas discharge type display device.

FIG. 5 is a characteristic diagram showing a relationship between relative luminance and discharge time of the gas discharge display device according to the above-described embodiment and the conventional gas discharge display device.

FIG. 6 is a cross-sectional view showing a conventional gas discharge display device.

FIG. 7 is a schematic view showing a display electrode body of a conventional gas discharge display device.

8A and 8B show changes in the discharge state of a conventional gas discharge display device over time, FIG. 8A is a schematic diagram showing an initial discharge state at the start of discharge, and FIG. 8B is an intermediate stage. FIG. 3C is a schematic diagram showing a discharge state in FIG. 4C, and FIG. 6C is a schematic diagram showing a final discharge state.

[Explanation of symbols]

 1 Front Glass Plate (First Substrate) 2 First Electrode Line 3 Back Glass Plate (Second Substrate) 4 Second Electrode Line 5 Partition 7 Display Electrode Body 7a Cathode 17 Aluminum Powder of Clake Particles

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuo Sakai 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside the Japan Broadcasting Corporation Broadcasting Technology Laboratory (72) Inventor Yasushi Motoyama 1-1-10 Kinuta, Setagaya-ku, Tokyo No. 72 Broadcasting Technology Research Institute of Japan Broadcasting Corporation (72) Inventor Mizuyoshi Gozawa 1-10-11 Kinuta, Setagaya-ku, Tokyo Inside Broadcasting Technology Research Institute of Japan Broadcasting Corporation

Claims (3)

[Claims] 1. A first substrate and a second substrate which are held to face each other by a partition wall, first and second electrode lines respectively provided on the first and second substrates, and the second substrate. An electrode body provided on a substrate and electrically connected to the second electrode wire, wherein a voltage is applied between the first electrode wire and the second electrode wire so that the first electrode wire and the electrode A gas discharge type display device for performing display by using gas discharge generated between the body and the body, wherein the electrode body is mainly composed of conductive powder having at least a surface layer made of scale-shaped conductive particles on a surface portion thereof. A gas discharge type display device comprising a cathode formed of a cathode material as a component. 2. The remaining portion of the electrode body, excluding the portion where the cathode is formed, is made of a conductive material having an electric resistivity smaller than that of the cathode material. Gas discharge type display device. 3. The gas discharge display device according to claim 1, wherein the conductive powder is an aluminum powder composed of scale-shaped aluminum particles.