JPS6362130A - Manufacture of fluorescent character display tube - Google Patents

Abstract

PURPOSE:To obtain a uniform display electrode layer of the same height as that of an insulation layer and a smooth phosphor screen having a uniform film thickness by printing graphite paste on recessed part of the insulation layer by the knife coater method. CONSTITUTION:After an aluminum film is applied to an insulation substrate 1 of glass, a feeder 2 is formed in a desired form. Next insulation paste of which major components are glass of low fusing point and a pigment is applied except for the part where a graphite display electrode 4 is to be formed, and baked, so that a black insulation layer 3 is formed. Then graphite paste is supplied to the recessed part formed by the lack of application of the paste by means of the paste supplying roll of a knife coater so as to form a graphite electrode 4 of the same thickness as the insulation layer 3. Then zinc oxide- based phosphor paste is applied on the graphite electrode 4 by screen printing method and baked, so that a phosphor layer 5 is formed. Thus a fluorescent character display tube of a high display grade free from nonuniformity of light emission can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a fluorescent display tube, and particularly to a method for forming display electrodes on an anode substrate thereof.

[Conventional technology]

In recent years, there has been an increase in the number of highly visible fluorescent display tubes that have an insulating layer that is the same color as the phosphor. Conventionally, this type of fluorescent display tube has Ag or Al on an insulating substrate 1 as shown in FIG.
A feed line 2 is formed by forming a feed line 2, and a hole or a recess is provided at a position where a display electrode is to be formed in an insulating layer 3 made of low-melting glass and a colored pigment having a through hole thereon, and the height of the surface of the insulating layer 3 is made within the insulating layer 3. Almost identical display electrodes 4 and a phosphor layer 5 were formed on the display electrodes by a screen printing method to form an anode substrate. A fluorescent display tube was manufactured by combining and sealing the thus obtained anode substrate with a 7° filament cover glass 8 using a known method.

[Problem that the invention seeks to solve]

However, in the above-mentioned method for manufacturing a fluorescent display tube substrate, display electrodes are provided in the recesses of the insulating layer by screen printing, so it is difficult to form a layer with a uniform thickness, and the printing of the phosphor on the display electrodes is difficult. Furthermore, in fluorescent display tubes that are manufactured in small quantities in a wide variety of products, the efficiency of the graphite printing process is significantly reduced.

[Means for solving problems]

In the method for manufacturing a substrate for a fluorescent display tube of the present invention, by printing graphite paste on the four parts of the insulating layer using a knife coater method, a uniform display T-pole layer having the same height as the insulating layer can be obtained, and a rough display T-pole layer can be obtained. When a phosphor layer is formed on a display electrode by a screen printing method, a uniform thickness of -fx, m can be maintained, and a smooth phosphor surface can be obtained. Furthermore, it has the feature that the efficiency of the graphite printing process is greatly improved.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

The outline of the knife coater used in the present invention will now be explained. Figure 3 shows the structure of this knife coater. Each roll 11,1 other than the steel roll supplying the paste'
2, 13, 14, 15, and 16 used rubber rolls to avoid damaging the anode substrate of the fluorescent display tube. Also, the first doctor 19 and the second doctor 20 are structured so that the scraped paste is sucked by a pump from a suction tube 21 and returned to the paste tank using a squeegee rubber for screen printing. Furthermore, a doctor roll 16 was provided to adjust the amount of paste applied so that a uniform film thickness could be obtained. Printing was carried out on an anode substrate having recesses in the insulating layer using a knife coater having these structures. Next, the method for manufacturing a fluorescent display tube of the present invention is shown in FIG. 1, which is a longitudinal cross-sectional view of the present invention. Let me explain 0 First, glass SP! A 1 μm thick AI film was temporarily deposited on the W substrate 1 by sputtering, and a power supply line 2 having a desired shape was formed by photolithography. Next, an insulating paste containing low melting point glass and pigment as main components is applied by screen printing except for the part where the graphite display electrode 4 will be formed, and baked at 520°C to form a black insulating layer with a thickness of 30 μm. 3 was formed. Next, the substrate having the recesses caused by not applying the paste in the insulating layer 3 described above was fixed to a stainless steel plate.
Graphite paste whose viscosity was adjusted to 0.00 (poise) was supplied to the paste supply roll of the knife coater described above, printed at a speed of 5 m/min, and then fired at 500°C to form a graphite electrode 4 with a thickness of 30 μm similar to the insulating layer 3. was formed.

In this case, in order to obtain the optimum film thickness, the doctor roll was sufficiently adjusted, and the printing pressure of the doctor blade was adjusted by the air cylinder 18, and 2 kg/cm2 was the optimum among those examined. Furthermore, a zinc oxide-based phosphor paste is applied onto the graphite electrode 4 by a screen printing method.
An anode substrate was obtained by forming a phosphor layer 5 by firing at 00°C. A fluorescent display tube obtained by combining and sealing the thus obtained anode substrate, a grid 6° filament 7, and a cover glass 8 using a known method (compared to a fluorescent display tube manufactured using a conventional manufacturing method, a graphite printing process is required) Efficiency was improved by 50%, and the characteristics of no unevenness in the luminescence of the phosphor were obtained.In addition, when the feeder line 2 was formed of Ag paste by screen printing, similar results were obtained. [Effects] As explained above, the present invention provides a fluorescent display in which a position Kl or a recess is provided for forming a display electrode in an insulating layer, and a graphite display electrode is formed within the recess with the surface height approximately the same as that of the insulating layer. In the tube, by forming the display electrodes using the knife coater method, the efficiency of the graphite printing process was greatly improved, and furthermore, a fluorescent display tube with excellent display quality without uneven light emission was obtained.

Incidentally, although graphite is used as the display electrode in the present invention, it goes without saying that the present invention does not depart from the scope of the present invention even if the display electrode is formed of other conductive materials.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a fluorescent display tube manufactured by the manufacturing method of the present invention. Further, FIG. 2 is a longitudinal sectional view of a fluorescent display tube manufactured by a conventional manufacturing method. Furthermore, FIG. 3 is a structural diagram of a knife coater used in the present invention. ]...Insulating board, 2...Power supply line, 3...
... Insulating layer, 4 ... Display electrode, 5 ...
Phosphor layer, 6...Guri. 7...Filament, 8...Cover glass, 11.12.13.14...Feed roll, 15°°°°°Coating roll, 16.
...Do pp-o-le, 17...Kawa paste tank, 18...Kawa air clear F, 19...1st doctor blade, 20...2nd doctor blade , 21...Paste suction tube 0 is shown in Figure 2.

Claims (1)

[Claims] In the method for manufacturing a fluorescent display tube, which is provided with a power supply line, an insulating layer, and a display electrode serving as a base for a phosphor layer on an insulating substrate, and which emits light by electrons from a filament, a recess is provided on the insulating layer; Display electrodes are printed using a roll coater (knife coater) that has a doctor blade in the recess.
1. A method for manufacturing a fluorescent display tube, characterized by forming a fluorescent display tube.