JPS6236340B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a gas discharge panel in which discharge cells constituting pixels of a display screen are arranged in a matrix. That is, it was devised for the purpose of improving the brightness and luminous efficiency, which are problems of this type of gas discharge display panel.

A conventional gas discharge display panel in which pixels are arranged in a matrix is constructed as shown in FIG. 1, for example. That is, in the gas discharge display panel 1', first, a large number of ribbon-shaped or linear anode electrodes 2' are arranged in parallel, and an insulating spacer is formed in which a large number of round window holes 3' forming discharge cells are bored. 4' is placed on the anode electrode 2', and a ribbon-shaped cathode electrode 6' having a small round window hole 5' is disposed perpendicularly to the spacer 4'. The cathode electrode 6' and the anode electrode 2' are connected via insulating spacers 7' and 8' to a front plate 9' made of, for example, a transparent glass plate, and a back plate 10 similarly made of a glass plate (which may be opaque). ′. The front plate 9' and the back plate 10' are sealed together at their respective peripheries to form an airtight envelope, and the interior of the envelope is once evacuated and then filled with neon, argon, helium. Gas that contributes to discharge light emission, mainly consisting of inert gases such as , xenon, and krypton, is sealed.

The problem with conventional gas discharge display panels as described above is that when trying to increase the display capacity and increase the display pixel density to compete with CRTs, etc., and to perform high-definition display by increasing the display pixel density, it is necessary to increase the display capacity as the pixels become smaller. As a result, not only the luminance of the luminescence itself decreases, but also the luminous efficiency of gas discharge luminescence, and various studies have been made to solve these problems. Examples include a method of providing a display memory function to a gas discharge display panel, and a method of improving the duty cycle by simultaneous multi-row driving (simultaneous driving of multiple discharge cells).

The present invention was devised in view of these problems associated with conventional gas discharge display panels, and in order to increase the surface area of the cathode and secure more discharge current related to gas discharge, We introduced a hollow cathode structure with a window hole in the part located in the discharge cell facing the electrode, and further improved the shape of the window hole in the cathode electrode that makes up this hollow cathode structure and the plate thickness of the cathode electrode. Even with narrow cathode electrodes with high arrangement density, it is possible to maintain a large discharge current while keeping the current density low. In other words, it is possible to achieve high luminance and high luminous efficiency while increasing the operating voltage. The object of the present invention is to provide a gas discharge display panel that is free of oxidation.

The structure of the present invention is that a large number of cathode electrodes with window holes forming a discharge cell are arranged on the front plate side, and a large number of anode electrodes are aligned with the positions of the window holes and spaced apart from the cathode electrodes by a predetermined distance. In a gas discharge display panel, the front plate and the back plate are arranged to intersect with each other on the back plate side, the front plate and the back plate constitute an envelope, and a gas contributing to discharge is sealed inside the envelope together with the two electrodes, The shape of the window hole of the cathode electrode is approximately rectangular, the length D of one side of the cathode electrode window hole, the plate thickness T of the cathode electrode, and the mean free path of electrons in the sealed gas is λ.
The present invention relates to a gas discharge display panel characterized in that, when e, 40λe≦D≦500λe (1) 10λe≦T≦100λe (2).

In order to set the optimal numerical range for D and T, we introduce the parameter λe, the mean free path of electrons, which is a concept commonly used when discussing the motion of electrons and atoms (or molecules). What was expressed is that, in general, the characteristics of gas discharge phenomena depend not only on the physical structure of the gas discharge display panel, but also on various variables such as the state of the gas medium space, that is, the type of gas enclosed, its vapor pressure, and temperature. Therefore, changing any one variable will change the discharge characteristics, making it difficult to determine whether the physical structure of the gas discharge display panel is truly optimal for the environment of the medium space created by the enclosed gas, etc. It was extremely difficult to make a qualitative judgment in advance. Therefore, it is directly and ultimately involved in the gas discharge mechanism, and qualitatively expresses the characteristics of the medium space as a function that depends on the various variables mentioned above, that is, in response to all types and conditions of the filled gas. It has the same length dimension as D and T, etc., and can be calculated theoretically once the value of each variable is determined, making it easy to use. ) This is because there is a close correlation in that the shape directly affects the electric field distribution in the discharge space and, by extension, affects the electron mean free path λe itself.

The present invention will now be explained based on an embodiment shown in the drawings.

1 in the figure is a gas discharge display panel main body of the present invention. 2 is a linear anode electrode, and a large number of them are arranged in parallel. Numeral 6 is a ribbon-shaped cathode electrode, and a large number of ribbon-shaped cathode electrodes are arranged to intersect with the anode electrode 2 at a predetermined interval. That is, for example, the cathode electrode 6 is placed on a plate-shaped insulating spacer 4 which is placed on the anode electrode 2 and in which a large number of rectangular window holes 3 are bored, and further, the cathode electrode 6 is placed on a plate-shaped insulating spacer 4 that is placed on the anode electrode 2 and in which a large number of rectangular window holes 3 are bored. A substantially rectangular (square in this embodiment) window hole 5, which is somewhat smaller than the window hole 3, but which is the gist of the present invention to be described later, is bored in the opposing portions. The cathode electrode 6 and the anode electrode 2 are connected to a front plate 9 made of transparent glass or the like through insulating spacers 7 and 8, respectively, and a back plate 0 made of glass or the like (which may be opaque). The insulating spacers 7 and 8 are also provided with window holes 7a having the same shape as the insulating spacer 4.
A plurality of holes 8a are bored at positions opposite to the window holes 5 of the cathode electrode 6. Also, like the conventional gas discharge display panel described above, the front plate 9 and the back plate 10 constitute an airtight envelope by hermetically sealing the periphery, and the inside of this airtight envelope is is filled with an inert gas such as neon, argon, xenon, or krypton.

However, in the gas discharge display panel of the present invention, the shape of the window hole 5 of the cathode electrode 6 shown in FIGS. 2 and 3 is a rectangular shape such as a square, or a modified side thereof, so that each side is inside the window hole. The cathode electrode 6 has a substantially pincushion shape with a curved protrusion in the direction, a substantially pincushion shape with chamfered four corners, or a rectangular shape or a substantially diamond shape with bag-like arcuate notches at the four corners. Let the length D of one side of the approximately rectangular window hole and the plate thickness T be the mean free path λ of electrons in the enclosed inert gas space that is responsible for discharge light emission.
If e is set to a value that satisfies the following relationships: 40λe≦D≦500λe (1) 10λe≦T≦100λe (2), the hollow cathode effect ( Hollow cathode effect: A phenomenon in which the recombination field of gas ions becomes particularly dense due to the presence of electric fields with different directions in close proximity, locally or completely overlapping. An efficient gas discharge display panel is realized.

Here, we will give an overview of general hollow cathode discharge. When a discharge operation is performed using the inner surface of a cylindrical or conical electrode as a cathode, or when parallel electrodes are placed facing each other and the inner surface is used as a common cathode. The discharge when operated as a hollow cathode discharge is called a hollow cathode discharge, and its general characteristics include the following points. In other words, since the ionized ion density in the cathode space is high, the discharge current density can be much higher than that in normal regular glow discharge, resulting in a lower discharge sustaining voltage and the cathode metal in the cathode space. Because of the high vapor density, the mean free path of space-traveling electrons becomes small, and the thickness of the cathode dark area (the non-luminous space that exists between the glow discharge area and the cathode) becomes small, which means that negative glow light emission becomes abundant. Moreover, since the opposing directions of the cathode surfaces are continuous or closed by the opposing cathode surfaces, the amount of spatter scattered to the outside is small. That is, the present invention aims to utilize various effects obtained by such hollow cathode discharge to improve the brightness and luminous efficiency of a gas discharge display panel.

In the present invention, in order to apply this hollow cathode discharge to gas discharge display panels, we conducted experiments with various cathode window hole shapes under various gas conditions. 4 As shown in Figure A, the four corners 5a, 5b, 5 inside the window hole 5
In c and 5d, the negative glow overlaps because the distance between the sides of the opposing cathode window holes is narrow, and unlike the conventional window hole 5' shape shown in FIG. 4B, the desired hollow cathode discharge does not occur. The fact that this occurs has been obtained. Furthermore, in order to increase the effect of the rectangular window hole 5, experiments were conducted by changing the thickness of the cathode electrode 6. The results of these experimental studies are shown in FIG.

In FIG. 5, the horizontal axis shows the length D of one side of the rectangular window hole, the vertical axis shows the relative brightness of the cathode electrode, and the curve A shows the relative brightness of the cathode electrode of the conventional gas discharge display panel. The relative brightness of the window hole (round hole),
Curve B is the relative brightness when the cathode plate thickness is 10λe and the window hole shape of the cathode electrode is square.
Curve C is the relative brightness when the thickness of the cathode electrode is 100λe and the window hole shape of the cathode electrode is also rectangular.

From the graph shown in Fig. 5, in order to effectively apply hollow cathode discharge to gas discharge display panels, the length D of one side of the cathode window hole and the thickness T of the cathode electrode must be 40λe≦D≦500λe. It has been found that it is necessary to set the condition such that 10λe≦T≦100λe.

FIG. 6 shows a comparison of the discharge voltage and current characteristics between the gas discharge display panel according to the present invention and a conventional gas discharge display panel using a flat cathode. According to this, in a conventional gas discharge display panel using a flat cathode, when the discharge current I is increased, the discharge sustaining voltage V also increases accordingly, but the gas discharge display panel according to the present invention In the case of , the increase in the discharge sustaining voltage V when the discharge current I increases is smaller than that in the case of a flat plate electrode, and this tendency becomes particularly noticeable as the plate thickness increases.

As described above, in the gas discharge display panel according to the present invention that utilizes hollow cathode discharge, the cathode current (discharge current) can be increased with a small cathode, the discharge sustaining voltage can be lowered, and the rate of increase in cathode current can be increased. Due to the excellent characteristics of hollow cathode discharge, such as being able to suppress spatter phenomenon to a lower level than that of conventional hollow cathode discharge, the operating voltage is low despite high brightness, and there is little occurrence of spatter phenomenon, which is a major cause of deterioration in display quality. A gas discharge display panel can be provided.

FIG. 7 shows a modified example of the shape of the cathode electrode window hole 5, and FIG. 7A shows an example in which each side of the window hole is curved and protrudes inward from the window hole to have a substantially pincushion shape. , Fig. 7B shows an approximately pincushion-like shape in which each side of the window hole is curved and protrudes inward from the window hole, and the four corners are chamfered, and Fig. 7C shows an approximate shape. It is formed by providing bag-like arcuate notches at the four corners of a rectangle, and in the modified examples shown in FIGS. The holes are identical, i.e. straight holes. On the other hand, the window hole 5 of the cathode electrode 6 shown in FIGS. 7D and F has a square shape in both the upper (toward the display surface) and the lower (toward the anode electrode) part, but there is a step in the middle. This is a modified example in which the length of one side of the window hole in the upper part is longer than the length of one side of the window hole in the lower part. The length gradually becomes shorter as it goes downward, forming a horn shape. Further, although not shown, the shape of the window hole may be asymmetrical with respect to the axis of the cathode electrode, for example, a substantially rhombic shape. In any of these modifications, the length of one side of the substantially rectangular shape forming the window hole of the cathode electrode described above (the length of this one side is the length of the side of the cathode electrode as exemplified in FIGS. 7A to 7C). In the case of a window hole and a substantially diamond-shaped window hole, the length of one side is determined by assuming a circumscribed rectangle that includes the window hole, and the window of the cathode electrode as exemplified in FIGS. If the length of the side of the hole is different on the front plate side and the back plate side, the length of the side of both the window holes on the front plate side and the back plate side is D, the plate thickness of the cathode electrode When T is the mean free path of the electron and λe is the mean free path of the electron, when the above D and T are under the following conditions: 40λe≦D≦500λe ………(1) 10λe≦T≦100λe ………(2) It is capable of exerting its effects.

However, according to the present invention, the window hole shape of the cathode electrode is made into a substantially rectangular shape, which is completely different from the conventional round shape,
By setting the length of one side of this approximately rectangular shape and the thickness of the cathode electrode under the above-mentioned constant conditions with respect to the mean free path of electrons in the sealed gas, it is possible to By making the window hole shape of the cathode electrode substantially rectangular rather than round, it is possible to improve the brightness due to the hollow cathode effect that can be effectively obtained at the four corners of the window hole, and this hollow cathode discharge The sustaining voltage is lower than that in normal gas discharge, and the discharge current is more likely to collect inside the window hole, so the luminous efficiency is good, and compared to a round window hole, the upper and lower corners of the four corners are limited. To provide a gas discharge display panel with extremely excellent display quality and high luminous area efficiency over the entire display surface, in which the presence of non-luminescent parts between discharge cells does not matter much when displaying characters, etc. became possible.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view of a conventional gas discharge display panel, Fig. 2 is a schematic perspective view of a gas discharge display panel according to an embodiment of the present invention, and Fig. 3 is a schematic perspective view of the gas discharge display panel in Fig. 2. 4A is a top view showing the discharge state of the window hole of the cathode electrode of the gas discharge display panel of the present invention, and FIG. 4B is the window hole of the cathode electrode of the conventional gas discharge display panel. Figure 5 is a top view showing the discharge state of the cathode electrode when the window hole is round, when the window hole is square and the plate thickness is 10λe, and when the window hole is square and the plate thickness is 100λe. FIG. 6 is a graph comparing the relative brightness of each of the two. FIG. 6 is a graph showing the voltage-current characteristics of the gas discharge display panel of the present invention and the conventional gas discharge display panel.
Figures A to C are top views showing modified examples of the window holes in the cathode electrode of the gas discharge display panel of the present invention, and Figures 7 D and E are other modifications of the window holes of the cathode electrode of the gas discharge display panel of the present invention. FIG. 7F is a sectional view of FIG. 7D, and FIG. 7G is a sectional view of FIG. 7E. 2... Anode electrode, 3... Window hole, 4... Insulating spacer, 5... Window hole, 6... Cathode electrode,
7, 8...Insulating spacer, 9...Front plate,
10...Back plate.

Claims (1)

[Claims] 1. A large number of cathode electrodes with window holes forming a discharge cell are arranged on the front plate side, and a large number of anode electrodes are aligned with the positions of the window holes and spaced apart from the cathode electrodes by a predetermined distance. In a gas discharge display panel, the front plate and the back plate constitute an envelope, and a gas contributing to discharge is sealed in the envelope together with the two electrodes. , when the shape of the window hole of the cathode electrode is approximately rectangular, the length of one side of the cathode electrode window hole is D, the plate thickness of the cathode electrode is T, and the mean free path of electrons in the filled gas is λe, A gas discharge display panel characterized in that 40λe≦D≦500λe (1) 10λe≦T≦100λe (2). 2. A gas characterized in that the substantially rectangular window hole of the cathode electrode according to claim 1 has a substantially pincushion shape with each side curved and protruding inward from the window hole. Discharge display panel. 3. The substantially rectangular window hole of the cathode electrode according to claim 1 has a substantially pincushion shape with each side curved and protruding inward of the window hole, and the four corners are chamfered. A gas discharge display panel characterized in that: 4. A gas discharge display panel characterized in that the substantially rectangular window hole of the cathode electrode according to claim 1 has a substantially rhombic shape. 5. A gas discharge display panel characterized in that the substantially rectangular window hole of the cathode electrode according to claim 1 is formed by providing bag-shaped arcuate cutouts at the four corners of the substantially rectangular shape. 6. The substantially rectangular window hole of the cathode electrode according to any one of claims 1 to 5 is a straight hole having the same shape and the same size on both the front and back surfaces of the cathode electrode. gas discharge display panel. 7. The substantially rectangular window hole of the cathode electrode according to any one of claims 1 to 5 is such that the length of one side of the window hole on the front plate side of the cathode electrode is the same as that of the window hole on the back plate side. A gas discharge display panel characterized in that it is formed longer than the length of one side of the panel.