JPH03285235A - Cathode for gas discharge type display panel - Google Patents

Abstract

PURPOSE:To achieve a good conductivity after baking in an atmosphere of air, and set the discharge starting voltage and minimum discharge maintaining voltage low by forming a cathode of Ni3B. CONSTITUTION:The cathode of a gas discharge display panel is formed of Ni3B. An Ni layer can also be formed as a primary electrode. The finest grains of several mum or less do not have a deterioration in an electric resistance by oxidation even after baking. Because the material is a boride, an electron radiation efficiency is high, the conductivity is good, the minimum discharge maintaining voltage and the discharge start voltage are set low, and the discharge characteristics are improved largely. The cost on a drive circuit can be low, and the reliability can be improved. Attachment of ions to the front surface glass side by sputtering by discharge is reduced, and the light emission efficiency of the display panel is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cathode for a gas discharge display panel that displays characters, graphics, etc. using gas discharge.

BACKGROUND OF THE INVENTION The cathode of a conventional gas discharge type display panel is manufactured by screen printing N1 paste on a glass substrate and baking it in an air atmosphere. Since this Ni paste can be easily fired in an air atmosphere, it can be easily produced. However, the 20N1 cathode has a relatively high discharge starting voltage and minimum discharge sustaining voltage, and cannot be said to be a sufficient cathode material.Also, Ni is sputtered due to ion sputtering due to discharge, and it adheres to the front glass side. The light transmittance decreases, the brightness decreases, and the lifespan of the display panel is shortened. Therefore, a two-layered cathode was developed in which Ni was used as the base electrode, LaB1 with a small work function was mixed with a small amount of alkali glass on the Ni base, and the mixture was made into a paste, screen printed, and fired. There is. In addition,
This type of cathode is described in, for example, the Technical Report of the Television Telegraph Society IPD59-10 (1981).

The problem to be solved by the invention L a B a has a work function of 2.66 eV,
Since it has a smaller value than Ni's 5.24 eV, if a cathode exhibiting the original value can be formed, a gas discharge type display panel with low discharge starting voltage and minimum discharge sustaining voltage can be obtained. . However, LaB tends to generate an oxide layer on its surface, and when it becomes small particles of several micrometers or less, the area of the oxide layer increases as the surface area oxidizes, and the overall electrical conductivity decreases significantly. On the other hand, in the above conventional technology, in order to reduce the manufacturing cost of the panel as much as possible, soda glass is used as the substrate, and the cathode is printed using a screen printing method that facilitates mass production. It is also fired in an air atmosphere. As a result, a part of LaBa is oxidized, and the electrical conductivity decreases by more than three orders of magnitude from the original value of LaBa.Therefore, the discharge starting voltage and minimum discharge sustaining voltage are also large, leading to problems such as instability. Ta. As a countermeasure against this problem, a method of firing in an inert gas atmosphere such as argon or nitrogen is used. However, although this method is effective for large LaBa powder particles having a particle size of several tens of micrometers or more, it is not effective for small particle sizes of several micrometers or less, and there are problems similar to those described above.

The present invention solves the above problems, and exhibits good conductivity even when fired in an air atmosphere, has low discharge start voltage and minimum discharge sustaining voltage, and can improve discharge characteristics. Therefore, it is possible to reduce the cost of the drive circuit, improve reliability, etc., and reduce adhesion of ions to the front glass side due to sputtering due to discharge.
Therefore, it is an object of the present invention to provide a cathode for a gas discharge type display panel that can improve the luminous efficiency of the display panel.

Means for Solving the Problems The cathode of the gas discharge type display panel of the present invention for achieving the above object is formed of N15B.

Further, a Ni layer can also be used as a base electrode.

Therefore, according to the present invention, there is no decrease in electrical resistance even when fired in an air atmosphere, and since it is a boride, it has a better electron emissivity than Ni alone, so it improves conductivity and discharges. The starting voltage and minimum discharge sustaining voltage can be lowered to improve the discharge characteristics, and the sputtering rate of ions due to discharge is lower than that of N1 metal, so it is less likely to be spattered and will not adhere to the front glass side. can be reduced.

Example Examples of the present invention will be described below.

First, we will compare the N15B used in the present invention and the conventional 1
The characteristics of aBi will be explained.

Since it is difficult to measure the absolute value of the electrical conductivity of powder, we will show the relative resistivity value depending on the type of powder.
The material was compacted into a pellet using cii, and the specific resistance was conveniently calculated from the dimensions of the pellet and the resistance value between both surfaces.

If the relative resistivity of LaBa particle size #325 mesh powder is 1, then LaB1 powder, which has a smaller particle size and an average particle size of 3.6 μm, has a relative resistivity of about 1000. On the other hand, Ni and B used in the present invention have an average particle size of 3 μm and a relative resistivity of 0.1 or less.

Next, these powders were heated at 600°C in an air atmosphere.
The characteristics after firing for 30 minutes are shown below.

While L a B a is an insulator with a relative resistivity of 10 or more, Ni and B have a relative resistivity of 0.1 or less, which hardly changes.

Next, a procedure for producing a cathode and a gas discharge type display panel using the above Ni and B powders will be described. By the generally known three-roller method, Ni, B powder, alkali glass powder, and organic solvent are adjusted to an appropriate viscosity.
A paste is prepared by sufficiently separating the bound particles.

As shown in FIG. 1, N1 paste is first screen printed as a cathode pattern on the rear glass substrate 1, and then fired to form a Ni base electrode 2.
Ni and B paste, which will become the cathode 3 of the present invention, is laminated on the i-base electrode 2 by screen printing. After printing, it is dried in air at 100°C, and then baked in air at 550'C to 660°C for 30 minutes. The back glass substrate l on which the cathode 3 is formed in this way, and the front glass substrate 6 on which the anode 4 as a transparent electrode and the partition wall 5 are provided are stacked together with the partition wall 5 in between, and the periphery is fired using glass flint. and seal airtight. Thereafter, the inside of the display discharge space 7 is evacuated to a high vacuum, and 10 to 500 orr of gas such as Ne-Ar or Ne-Xe is introduced to produce a gas discharge type display panel.

As described above, regarding the discharge characteristics of the gas discharge type display panel obtained using the N15B cathode 3 of the present invention example formed on the Ni base electrode, the Ni
and a comparative example using LaBa formed on a Ni base electrode.

FIG. 2 shows the gas pressure and the minimum discharge sustaining voltage, respectively. As is clear from FIG. 2, the voltage of the Ni, B cathode 3 of the embodiment of the present invention is significantly lower than that of the conventional Ni cathode or the LaBa cathode provided on the Ni base electrode. . Furthermore, the voltage-current characteristics are very stable over time.

As described above, the cathode of the above embodiment is very effective in improving the discharge characteristics compared to the conventional cathode. Effects of the Invention As described above, according to the present invention, the cathode is made of Ni, B, Even if this N15B is made into fine particles of less than a micrometer and is fired in air, it will not deteriorate in electrical resistance due to oxidation like LaBa, and is more efficient in electron emission than Ni alone because it is a boride. is high, so the conductivity is good and the minimum discharge sustaining voltage and discharge starting voltage are low.
Discharge characteristics can be significantly improved. therefore,
It is possible to reduce the cost of the drive circuit and improve reliability. In addition, there is less adhesion of ions to the front glass side due to sputtering caused by discharge, and therefore, it is possible to improve the luminous efficiency of the display panel.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a gas discharge type display panel constructed using a cathode according to an embodiment of the present invention, and Figure 2 is a graph showing the gas pressure and minimum discharge of the cathode of the embodiment of the present invention and a conventional cathode as a comparative example. FIG. 3 is a characteristic diagram showing a sustain voltage. 1... Back glass substrate, 2... Ni base electrode, 3... Cathode, 4... Anode, 5
......Partition wall, 6...Front glass substrate, 7
・・・・・・Discharge space.

Claims (2)

[Claims] (1) A cathode of a gas discharge display panel made of Ni_3B. (2) The cathode of a gas discharge type display panel according to claim 1, comprising a Ni layer as a base electrode.