KR890001433B1 - Fluorescent lamp of attached method - Google Patents

Abstract

This invention is a fluorescent lamp attaching method using low melting point glass (Frist) as attaching material. This fluorescent lamp attaching method consists of three steps. In the first step a front window glass cover and a base glass plate are spreaded with Frit, before the part except metal parts are heated in oxidation atmosphere and are kept at 420 to 480 degrees of Celsius for a normal time to release gas decomposed. In the second step metal parts are inserted and are heated to 200 to 250 degrees of Celsius in oxidation atmosphere to decompose the residual gas. In the third step the furnace is metathesised into inert atmosphere and is heated to 420 to 460 degrees of Celsius.

Description

Sealing method of fluorescent display tube

The figure is an exploded perspective view of a fluorescent display tube.

* Explanation of symbols for main parts of the drawings

10: windshield 11: upper frit

20: exhaust pipe 41: grid

30 spacer 42 filament

40: supporter 43: lead frame

50 substrate glass 51 lower frit

52: fluorescent pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing method of a fluorescent display tube using low melting glass (hereinafter referred to as frit) as a sealing material in a sealing process of a fluorescent display tube.

The fluorescent display tube uses a phenomenon in which hot electrons are emitted from the filament and collide with the phosphor to emit light. Therefore, since a high vacuum state is required inside the fluorescent display tube, the frit is used as a sealing material. In the process of plastic fusion, the discharge process of discharging binder gas, which is inevitably generated from decomposition of organic substances contained in frit, must be carried out. Since the process is performed at a high temperature, it is accompanied by a secondary problem of preventing electron emission deterioration due to oxidation of the metal parts embedded in the display tube and preventing contamination of the cathode 1 phosphor due to the high temperature emission gas.

A well-known sealing process is explained in full detail by a mounting drawing as follows. First, the ceramic or glass plate is cut to the required standard, washed and dried to form the substrate glass 50 and printed with a predetermined pattern 52 to produce a substrate. At this time, after printing the first conductive layer on the lowermost layer for printing the four layers, an insulating layer mainly composed of low melting point glass is formed, and the second conductive layer (segment layer) and the phosphor are printed.

At this time, the firing temperature of each layer is a high temperature of about 400-600 ℃.

Phosphor forms a substrate using a low-speed excitation phosphor, nitro cellulose resin, acrylic resin, etc. as a binder (Binder).

The lower frit 51 is applied to the outer upper end surface of the substrate glass 50 and used as the spacer 30 and the adhesive agent.

The supporter 40 supporting the integrated metal parts is placed on the upper portion of the substrate glass 50 fabricated as described above, in which a very thin stainless steel sheet is mashed using a photo-etching technique. Ternary compound, which is a material for emitting hot electrons to the hydrogenated black lead frame 43 and fine tungsten wire to improve adhesion to glass using grit 41 manufactured in the form and iron-nickel-chromium alloy ( A filament 42 having BaCO ₃ , CaCO ₃ , and SrCO ₃ ) attached thereto by an electrodeposition method, and a getter (not shown) which adsorbs the residual gas in the tube to increase the degree of vacuum are provided.

The metal parts are extremely precisely manufactured, so that they are easily oxidized and fouled due to the high temperature emission gas in the subsequent discharge process and the firing process.

The spacer 30 and the exhaust pipe 20 are placed on the upper part of the supporter 40, and the upper frit 11 is coated on the supporter 40 again, and the transparent film is formed to prevent the influence of the electric field difference with the outside. SnO ₂ coated windshield 10 is covered. At this time, the large amount of upper frit 11 used to fuse the spacer 30 and the exhaust pipe 20 with the windshield 10 will also release a considerable amount of decomposition gas in the subsequent process.

It is a known method of sealing a fluorescent display tube that a combination of each of the above-listed components is fabricated in a temporary manner using a furnace (Furncae) to produce a fluorescent display tube.

There are several conditions to get a good quality fluorescent tube,

(A) To raise the airtightness of frit by releasing the binder gas of frit glass to the maximum.

(B) To prevent fouling of cathodes, phosphors, etc. due to emission gas;

(C) It is concentrated to prevent oxidation of embedded metal parts and to prevent a decrease in vacuum and electron emission.

In the known method, since the parts are combined and fired at one time, the inside of the display tube is closed except for the exhaust pipe 20, so that a large amount of the exhaust gas is discharged only to the narrow exhaust pipe, so that it is difficult to completely discharge the metal parts. The above conditions for obtaining a high-quality fluorescent display tube such as oxidized fouling cannot be satisfied, and the result of the increase in the defective rate was inevitably left.

As a subsequent invention improved on this

(A) A method in which the encapsulation preprocess is carried out in an inert atmosphere (nitrogen, argon gas).

This method can prevent the oxidation of metal parts, but it is not possible to decompose and erase the binder gas due to lack of oxygen due to inert atmosphere. Dignity falls.

(B) A method in which the sealing step is carried out only in an oxidizing atmosphere (in air).

This method satisfies the requirements of (a) and (b) of the above conditions, but the deterioration of vacuum due to the oxidation of metal parts and the oxidation of filaments with tungsten-based metals cause the fatal defects.

(C) After applying the upper frit 11 and the lower frit 51 to the sealing portion of the windshield 10 and the substrate glass 50, insert the metal parts to fix in the shape of a sealed container and then binder gas in one step Sealing by heating in an oxidizing atmosphere to decompose and replacing the inside of the furnace with an inert gas atmosphere in two steps.

This method can obtain a better sealing state than the above (A), (B) method, but because the gas inside the sealed display tube is discharged only to the narrow exhaust pipe 20, the gas inside the tube is not completely discharged.

As a result, there is a problem in that the phosphor and the cathode are not contaminated and the partial oxidation of the metal part due to the one-stage heating that is heated in an oxidizing atmosphere of about 350 ° C. cannot be prevented.

The present invention relates to a method of sealing a fluorescent display tube for solving the above-mentioned problems, which will be described in detail as follows.

[Step 1]

After the windshield 10, the exhaust pipe 20 and the spacer 30 are assembled using frits, the frit is applied to the lower portion of the spacer 30 again to form a windshield portion.

Substrate glass 50 is separately coated with a lower frit 51 and maintained at a high temperature of about 420-480 ° C. for about 20-30 minutes in an acid atmosphere having good air circulation, thereby decomposing and erasing organic substances contained in the frit as much as possible. To complete the integral windshield portion and the separate substrate glass 50 portion.

[To second process]

Place the supporter 40 supported on the metal parts on the substrate glass 50, cover the windshield glass, and oxidize the temperature to 4-7 ℃ per minute to a relatively low temperature of 200-250 ℃ while applying an appropriate load. The residual binder gas is decomposed by heating to raise the temperature in the atmosphere.

[To third process]

The inside is replaced with an inert gas atmosphere at 200-250 ° C., heated to about 420-460 ° C., maintained for about 5 minutes, and then cooled slowly to complete sealing.

By adopting the method as described above, by disassembling and erasing the binder gas at the sealing part while completing the windshield part in the first step, it is advantageous for mass production because no separate equipment is required, and the decomposition emission generated during the combined firing with the substrate glass 50 is eliminated. The gas can be discharged to the outside, and a small amount of remaining gas can be decomposed and discharged in the second process to prevent airtightness of the frit and contamination of the cathode and the phosphor, and the decomposition of the gas is completed in the first and second heating processes. Since it is possible at the low temperature of the 3rd process of an inert atmosphere, and can suppress the oxidation of a metal part as much as possible, it satisfies all the conditions of (a)-(c) mentioned above.

Claims (1)

In the process of sealing the fluorescent display tube, the integrally formed front windshield cover and the separate substrate glass part are each coated with frit, and the parts other than the metal parts are heated in an oxidizing atmosphere and maintained at 420-480 ° C for a predetermined time. Discharging the gas, decomposing residual gas by inserting a metal part and heating to 200-250 ° C. in an oxidizing atmosphere, and replacing the furnace with an inert atmosphere and heating it to 420-460 ° C. in a three-step heating process. Sealing method of the fluorescent display tube, characterized in that made.

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