JPH0449739B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a gas display device that displays a color image by coating a fluorescent substance on the inner surface of a front plate or a back plate that divides the discharge space of each gas discharge cell by arranging it in a matrix. The present invention relates to a discharge display panel, which has been improved in particular to improve luminous efficiency and to be simple and easy to manufacture.

(Prior Art) Conventionally, in various DC type gas discharge display panels including memory type, a high luminous efficiency of about 0.3%, for example, has been achieved by using the light emission of the positive column generated during gas discharge. By adding a function, the light emitting time can be extended, and the display brightness can be further increased. However, in a gas discharge cell using a positive column, it is necessary to lengthen the discharge path in order to generate a positive column, and in order to configure a long discharge path, a cell sheet is required to separate the inner surfaces of the front and rear panels. Furthermore, since it requires a manufacturing technique for applying phosphor to the inner wall surface of the elongated cell space bored in the cell sheet, it is difficult to manufacture, is not suitable for mass production, and has the drawback of increasing manufacturing cost.

On the other hand, a gas discharge cell that uses negative glow generated by gas discharge to emit light has a luminous efficiency of 0.02%.
Because of the extremely low level, it was almost abandoned for use in color displays, and the instability of gas discharge caused by small currents was said to be a serious drawback that made it impossible to put it to practical use.

(Summary of the Invention) An object of the present invention is to eliminate the above-mentioned conventional drawbacks, utilize negative glow, which was previously thought to be impractical especially for color display, based on new knowledge, and easily It is an object of the present invention to provide a new gas discharge display panel that can be easily manufactured with a simple structure, operates stably even with a small current, and can obtain high luminous efficiency.

That is, in the gas discharge display panel of the present invention, a phosphor is coated on the inner surface of at least one of a front plate and a rear plate that partition gas discharge spaces in which gas discharge cells are arranged in a matrix. The product _P0・d of the distance d between the cathodes and the reference pressure _P0 in the cell of the ultraviolet radiation gas is 0.5 to
The gas discharge cells are constituted by negative glow cells in the range of 8 Torr cm, and for each gas discharge cell, the area of the cathode does not exceed 15% of the total inner wall area, and for any consecutive period of 50 μsec. It is characterized in that the average discharge current at no more than 50 μA.

(Example) The present invention will be described in detail below with reference to the drawings.

First, the inventors' new findings regarding negative growth cells, which form the basis of the present invention, will be explained.

A gas discharge cell that uses the negative glow generated during gas discharge for light emission, that is, a negative glow cell, generally has a first
Conventionally, as shown in Figure 1b, it has been assumed that the luminous output is proportional to the discharge current and the luminous efficiency is almost constant with respect to the discharge current. was. In addition, in a negative glow cell using the green phosphor Zn ₂ SiO ₄ :Mn, it has been recognized that the luminous efficiency increases to some extent in the micro current region based on the saturation characteristics of the phosphor itself.

However, in the microcurrent region where the discharge current is less than 50μA, the gas discharge becomes unstable, so
The mode of its operation has not been fully elucidated until now. In order to clarify the operating characteristics of a negative glow cell in such a small discharge current region, the present inventors reduced the cathode area as described in Japanese Utility Model Publication No. 1981-8130, which was proposed by the present inventors. Detailed measurements of the operating characteristics of a negative glow cell, which stabilizes gas discharge by stabilizing the gas discharge, revealed that, contrary to conventional expectations, the luminous efficiency sharply increases when the current value approaches 50 μA. We discovered that there are modes of operation.

The configuration of the negative growth cell that was the object of the above-mentioned discovery by the present inventors is shown in FIG. 2a, and the mode of its movement is shown in FIG. 2b. The configuration of the test negative growth cell is as follows:
As is clear from the comparison of Fig. 2a with Fig. 1a, the display part is almost the same as the display part of a conventional negative glow cell, and the cathode material is _BaAl4 , and the filler gas is He-Xe2%, 200 Torr. However, as will be explained in detail later, it was found that the operating characteristics showed almost the same tendency, without much dependence on the cathode material or the filler gas. Further, even in the case of pulsed discharge operation, the same tendency was maintained as long as the average discharge current was made small. In other words, the operating characteristics of the test negative glow cell, as shown in Figure 2b, are a region of average discharge current that is much smaller than the average discharge current region of the conventional negative glow cell shown in Figure 1b. , the luminous efficiency expressed as the ratio of the luminous output P ₀ to the discharge current 1 is dramatically different from the ratio line expected from the conventional characteristics shown in FIG. 1b, depending on the characteristics of the luminous output P ₀ It showed a dramatic rise.

The basic structure of the gas discharge display panel of the present invention based on the above-mentioned new knowledge regarding the luminous efficiency of negative glow cells is shown in FIGS. 3a and 3b. As shown in the figure, the rectangular discharge cells are individually independent due to the cross-shaped cell sheet CS inserted between the front glass plate FG and the rear glass plate RG, but the cell sheets CS are enclosed through a small gap. The moth is uniform and communicates with all discharge cells. In order to stabilize the discharge, the cathode C of each discharge cell is covered with an insulating film along with the cathode bus bar CB deposited on the inner surface of the rear glass plate RG, except for the opening in each cell. Note that the insulating film can also be replaced by a phosphor layer Rh deposited on the inner surface of the rear glass plate RG, but if it is made of thick film glass, the discharge can be reliably stabilized. can. Further, the phosphor layer Ph is deposited on the insulating film and the cathode bus bar CB by a printing technique or the like.
Note that, in the configuration example shown in the figure, the display panel is configured as a reflective type, so that the phosphor layer Ph can be deposited to a sufficient thickness. In addition, those cathodes C,
The electrode conductor pieces such as the cathode bus bar CB or the display anode DA attached to the inner surface of the front glass plate FG can be easily manufactured using well-known and commonly used manufacturing techniques such as thick film printing.

Therefore, in the gas discharge cell of the present invention having the configuration shown in the drawings, in order to form a negative glow during discharge, the discharge distance d expressed as the distance between the front glass plate FG and the rear glass plate RG and the type of filled gas are used. and the sealed gas pressure p. First, when using a rare gas system, which is the most important filler gas for ultraviolet radiation, the filler gas average P ₀ standardized based on experiments is P ₀ = max {0.8P _He・1.5P _Ne , 2PAr , 6 _Kr , 9P _Xe } (1). In addition, P _He in the above formula (1),
P _Ne , P _Ar , P _Kr , P _Xe are filled gas He,
It represents the partial pressure of Ne, Ar, Kr, and Xe.
Therefore, in a gas discharge cell using conventional positive column light emission, the normalized gas pressure P ₀ and the discharge distance d
The product P ₀ ·d is 12≦P ₀ ·dTorr·cm, whereas in the negative glow cell according to the present invention, it is 0.5≦P ₀ ·d≦8.

In addition, in gas discharge display panels, when a cathode made of a Ni-based metal material is generally used, mercury (Hg) is generally introduced into the discharge space to prevent spatter, but the partial pressure of the mercury vapor is very small. Therefore, we will ignore it here.

On the other hand, the discharge current in the negative glow cell of the present invention having the configuration shown in the figure is limited to 50 μA or less. moreover,
In the negative glow cell of the present invention having the configuration shown in the figure, in order to stabilize the discharge, the exposed surface of the cathode C is made small as described above, but it exceeds 15% of the total inner wall surface area within the discharge cell. Limit it so that it doesn't.

Note that in a discharge cell having a configuration in which an inner wall surface is not provided between the individual discharge cells by cell sea CB, the area of the inner wall surface of the discharge cell is determined by arranging a virtual cell inner wall at the boundary of each discharge cell region.

In the configuration example shown in Figure 3, the display anode DA is disposed on the inner surface of the front glass plate FG, but depending on the material of the cathode C, the cathode C may be disposed on the inner surface of the front glass plate FG. In some cases, it was advantageous to move the display anode DA to the inner surface of the rear glass plate RG. For example, when a material with a small work function such as BaAl ₄ was used for the cathode C, the luminous efficiency was increased by about 1.5 times. In addition,
Even in such a case, an opening is provided in the cathode C and only the opening is exposed, and the other metal members constituting the cathode are covered with a transparent insulating film, or
It is necessary to ensure that the cathode material is deposited locally.

In addition, as another example of the structure of the negative glow cell according to the present invention, as shown in FIG. 4, if the cathode C is raised above the cathode bus line CB and protrudes from the surface of the phosphor layer Ph, the luminous efficiency can be increased by 20 % increase. If at least the surface layer of the protruding portion of the cathode C is made of a material with a small work function, the voltage of the negative glow cell can be lowered, so that the luminous efficiency is further increased.

Next, configuration examples in which the present invention is applied to various memory type gas discharge display panels will be described.

As can be seen from the luminescence characteristics of the test negative glow cell shown in FIG. 2b, the negative glow cell according to the present invention has the following characteristics:
Although it has excellent luminous efficiency, the luminous output itself is small, so a sufficient display brightness cannot be obtained unless the luminous time is extended by some method. For this purpose, the gas discharge display panel of the present invention needs to be constructed in the form of various memory type gas discharge display panels, and the present invention may be applied to various memory type display panels to improve luminous efficiency. An example of a configuration in which a negative glow discharge with a high value is performed is shown below.

(1-a) Memory-type display panel using resistors An example of a structure in which the present invention is applied to this type of memory-type display panel is shown in FIGS. 5a and 5b. In the illustrated configuration example, for the display anode bus bar DAB,
A display anode DA is connected to each cell via a resistive element R. This resistance element R and display anode bus bar
The exposed part inside the DAB cell is a transparent insulator IG,
For example, cover with glass material. Further, the resistance value of the resistive element R is preferably set in the range of 100 Kft to several tens of MΩ. It should be noted that the same effect can be obtained even if this resistance element R is disposed on the inner surface of the rear glass plate RG and interposed between the cathode bus bar CB and the cathode C, contrary to the state shown in the figure. , the same effect as described above can be obtained even if the electrode on the inner surface of the front glass plate FG in the illustrated configuration is operated as a cathode.

(1-b) Pulse Memory Operation Display Panel It is easily understood that in the gas discharge display panel having the configuration shown in FIG. 3, a so-called pulse memory operation can be performed by repeatedly applying a panel array to the display anode DA. The repetition period of the applied pulse train is within the range of 2μs to 50μs, and the average value of the discharge current in any consecutive 50μs period is 50μA.
It is necessary to set the signal waveform of the drive pulse train so that it does not exceed . In particular, the product of the discharge current value and discharge time width in one pulse discharge is:
It is easier to obtain good luminous efficiency by not exceeding 10 nc (nano coulombs). Under such operating conditions, the luminous efficiency is close to the luminous efficiency when DC discharge is performed at a discharge current value approximately equal to the average current. In addition, if the resistance value of the resistance element R in the configuration shown in No. 5 is set to several hundred kilohms or less,
A pulse memory operation with current limitation can be performed, and transition to arc discharge and damage to the discharge cells accompanying the transition can be prevented.

On the other hand, in order to display a moving image with halftones on a gas discharge display panel, it is necessary to display images in 6 to 8 subfields within one field period, and in each subfield period,
It is necessary to scan all the rows of the display surface within a short period of about 2 m sec to cause the display discharge cells in each row to perform the required gas discharge. For this purpose, in the negative glow discharge display panel according to the present invention, it is necessary to configure the display panel by combining each negative glow cell for display with an auxiliary discharge cell for scanning. An example of the structure of the panel will be described below.

(2-a) Burrows-type display panel The conventional negative glow cell with the configuration shown in FIG. Because it is unstable, the exposed part of cathode C
Must be limited to 15% or less.
For this purpose, it is necessary to expose only the priming hole portion of the cathode C, and cover the other portions, including the phosphor, with an insulating material. A negative glow discharge display panel having such a configuration can obtain relatively high luminous efficiency when operated as a pulse memory type display panel. Furthermore, if a resistor R is inserted between the display anode DA or cathode C and each bus bar as shown in FIG. 5, it can also be operated as the above-mentioned resistive memory type display panel, increasing luminous efficiency. You can also do it.

In addition, in the display panel having the configuration shown in FIG. 1a, the cell sheet CS1 section is used as a conductor for the cathode
A ribbon-shaped cathode conductor CR sandwiched between CS2 and CS2 is used, but as the cell pitch is made smaller to create a high-resolution display panel, contact between the ribbon-shaped cathode conductors occurs, causing manufacturing problems. There is a risk of causing

The configuration example shown in FIG. 6, which will be described in the next section, is configured to avoid the occurrence of such a problem. In the display panel with the configuration shown in the figure, all components such as the above-mentioned cathode C, cathode bus bar CB, display anode DA, scanning anode SA, resistor R, etc. can be printed only with thick film, or with thick film printing and thin film. It is formed by only adhering.

(2-b) Display panel with auxiliary discharge area for scanning The configuration example shown in Figures 6a and b is a front anode type in which a display anode DA is disposed on the inner surface of the front glass plate FG. It is also a resistive memory type that has a resistive element R directly on the anode DA, and is formed by thick film printing on the inner surface of the front glass plate FG to form a partition wall between each cell.The inner surface of the rear glass plate RG at the lower end of the cell sheet CS A scanning auxiliary discharge cell is formed by a scanning anode SA attached to the lower end surface of the cell sheet SC and an exposed portion of the cathode bus bar CS curved along the concave cutout. The scanning anodes SA attached to the lower end surface of the cell sheet CS are arranged in one row for every two rows of display anodes DA.
It is configured to commonly exert a priming effect on two display cells adjacent on both sides. In addition, the recessed part provided on the inner surface of the rear glass plate RG is in the form of a groove facing the scanning anode SA.
Formed by cutting, etc. A cathode bus line CB is disposed across the groove, and the conductor of the cathode bus line CB is exposed only at the center of the bottom surface of the display cell portion to form the cathode C.

In such a configuration, the exposed portion of the cathode bus bar CB in the recessed part of the rear glass plate RG and the scanning anode SA
An auxiliary discharge is generated near the point of proximity to the cell sheet, and the excited particles generated by the auxiliary discharge are transferred to the cell sheet.
The priming effect is performed by diffusing to the display cell side through the slit SL between the CS and the recessed part. Note that the slit SL also functions as a ventilation path for introducing the sealed gas into each cell.

The display panel of FIG. 6 with such a configuration has a fifth
As in the illustrated display panel, the resistive element R
If it is made smaller, it can also be operated as a pulse memory type display panel. Furthermore, it is well known that even if the positional relationship between the anodes DA and SA and the cathode C is completely reversed, they will operate in exactly the same way.
It is also well known that it can be disposed on the inner surface of RG and inserted in series with cathode C.

Next, constituent materials, manufacturing methods, and operational aspects common to the various configuration examples described above of the negative glow discharge display panel according to the present invention will be explained.

(3-a) Electrode conductor and cathode material A 42-6 alloy ribbon or wire is usually used as the cathode material. In addition, a Ni-based paste is used as a printing material for thick films and the like, and is used after being fired.
It has good conductivity as a material for cathode busbars.
It is also possible to use AU, Ag, Cu, Al, etc. or alloys or mixtures thereof, with Ni coated only on the surface by printing, plating, vapor deposition, sputtering, etc. As the anode material, the above-mentioned metal materials may be used as they are, and as the cathode material, it is well known that the above-mentioned metal materials are coated with a surface layer of an electron-emitting substance. The electron emitting materials, that is, the so-called emitters include BaAl ₄ , Ba, LaB ₆ ,
BaAl ₂ O ₄ , Mg, etc., and mixtures and alloys thereof are used.

(3-b) Insulator If the insulator film used is relatively thin, a transparent glass thick film is used. Note that, of course, the insulating thin film can be formed by a conventional manufacturing method such as vapor deposition. Further, when forming a thick insulating layer such as a cell partition wall, that is, a so-called bank or a cell sheet, a thin plate of glass, photosensitive glass, Macol, etc. may be formed by etching or machining. Furthermore, such a thick insulating layer can also be formed by printing and baking a glassy ultra-thick film paste.

(3-c) Resistor Antibodies used in gas discharge cells are usually
Although a thick film of RuO ₂ is used, a thin film of a transparent conductor such as Ta, NiCr or SnO ₂ can also be used.

(3-b) Phosphor For red color, (Y, Gd) BO ₃ :Eu,
YBO ₃ : Eu, for green color Zn ₂ SiO ₄ : Mn,
BaAl ₁₂ O ₁₉ :Mn, for blue color
BaMgAl ₁₄ O ₂₈ :Eu ²⁺ , BaMg ₂ Al ₁₄ O ₂₄ : Eu ²⁺ ,
Each is applied using printing, spraying, a photosensitive adhesive method, etc. It is sufficient that the phosphor layer in the display panel of the present invention is coated on the flat surface of each discharge cell, that is, on the inner surface of the front glass plate or the back glass plate, but it is also sufficient to coat the phosphor layer on the wall surface of the cell sheet. By doing so, the luminous efficiency can be further increased.

(3-e) Manufacturing method For pattern formation of each component of the discharge cell,
It is well known that it is suitable to use photolithography in addition to printing methods.

In addition, when manufacturing a resistive memory type display panel,
In addition to the inner surface of the front glass plate, the resistance element can be placed on the inner surface of the rear glass plate. In any case, it is sufficient to arrange the resistance element so that it can be inserted in series with the discharge electrode of each discharge cell.

(Effects) As is clear from the above description, according to the present invention, it is possible not only to realize a gas discharge display panel with significantly higher luminous efficiency than the conventional one, but also to achieve low current operation of the negative glow discharge cell. Since the phosphor layer can be applied to the flat surface of the discharge cell to effectively emit light, a special effect can be obtained in that a high-density, high-efficiency display panel with a fine cell pitch can be easily produced.

Furthermore, when scanning priming discharge is used in combination, high-speed addressing becomes possible, making it suitable for displaying television images.

[Brief explanation of the drawing]

Figures 1a and b are cross-sectional views and characteristic curve diagrams respectively showing the configuration and luminescence characteristics of a conventional negative glow discharge display panel, and Figures 2a and b are the basic configuration and luminescence characteristics of a negative glow discharge display panel according to the present invention. cross-sectional diagrams and characteristic curve diagrams respectively showing
FIGS. 3a and 3b are a sectional view and a plan view respectively showing an example of the structure of the gas discharge display panel of the present invention, FIG. 4 is a sectional view showing another example of the structure of the gas discharge display panel, and FIGS. 6b is a sectional view and a plan view showing still another example of the gas discharge display panel, and FIGS. 6a and 6b are a plan view and a sectional view respectively showing still another example of the gas discharge display panel. It is. FG...Front glass plate, RG...Rear glass plate,
DA...display anode, SA...auxiliary scanning anode, CR
...Cathode conductor, PH...Priming hole, Ph...
Phosphor layer, CS, CS1, CS2...Cell sheet, C
...Cathode, CB...Cathode bus bar, d...Discharge distance,
IG...Insulating glass coating, IR...Insulating material, DAB...
...display anode busbar.

Claims (1)

[Scope of Claims] 1. In a gas discharge display panel in which a phosphor is coated on the inner surface of at least one of a front plate and a back plate which partition gas discharge spaces by arranging gas discharge cells in a matrix, the distance between the anode and the cathode is The product P ₀・d of d and the reference pressure P ₀ in the cell of the ultraviolet radiation gas is
The gas discharge cells are constituted by negative glow cells in the range of 0.5 to 8 Torr cm, and for each gas discharge cell, the area of the cathode does not exceed 15% of the total inner wall area, and any continuous
A gas discharge display panel characterized in that the average discharge current during a period of 50μsec does not exceed 50μA. 2. The display panel according to claim 1, wherein the gas discharge cell has a memory function,
The current/time width product in one pulse discharge is
A gas discharge display panel characterized by a pulse memory operation not exceeding 10nC.