JPH0210542B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a display tube, and more particularly to a method for manufacturing a display tube having a structure that does not include an exhaust pipe for exhausting the inside of the display tube. A fluorescent display tube will be described below as an example of the display tube.

A fluorescent display tube is a display tube that emits electrons by heating a filament-shaped cathode disposed inside the envelope, and emits electrons by impinging on the phosphor layer on the anode. The interior is kept under high vacuum. Further, the envelope is constructed of a flat box made of glass parts, and an exhaust pipe for exhausting the air inside is installed through a part of the box.

As shown in FIG. 1, a conventional fluorescent display tube is made by stacking a glass substrate 1 on which electrodes, etc. are formed on the inside, and a front container 2 formed from glass into the shape of a flat-bottom boat, and then heating and melting a sealing material 3. After sealing, the air in the envelope was removed through an exhaust pipe 4 provided through the substrate 1, and in a state of high vacuum, the exhaust pipe 3 was heated and melted to seal and cut. Furthermore, as shown in FIG.
The front container 2 consisting of the front panel a and the front panel 2b are stacked together, and the sealing material 3, which is mainly composed of glass, is applied to each joint by heating and melting to seal it and penetrate a part of the side panel 2a. The air inside the envelope is evacuated by a vacuum pump through the exhaust pipe 4 provided as a vacuum pump, and the exhaust pipe 4 is heated and melted in a high vacuum state of about 1×10 ^-6 Torr to seal it.
Furthermore, the getter was blown away, creating a high vacuum inside the tube. The heating and melting of the exhaust pipe 4 causes cracks in the envelope because the root of the exhaust pipe 4 is sealed by heat.

Therefore, in order to heat and melt a position a certain distance from the envelope, a portion of the exhaust pipe 4 remains by a few millimeters and is formed to protrude outside the display tube, as shown in Figs. 1 and 2. So it was hot. This exhaust pipe 4 is
Although it is necessary during exhaust, it is not only unnecessary after exhaust, but it often becomes a hindrance when installing the fluorescent display tube in the display set or when designing the layout of the display set, and it is a problem in miniaturization. I was getting used to it.

Therefore, a fluorescent display tube without the exhaust pipe 4 is required, but none has been put into practical use. However, as a method for manufacturing a fluorescent display tube without an exhaust pipe, there is Japanese Patent Application No. 121472/1982 (Japanese Unexamined Patent Publication No. 45865/1989) titled ``Method for Manufacturing a Small Electron Tube.'' In this method, frit glass is applied to the sealed portion of the glass substrate and front container so that the surface becomes uneven, and then assembled into an envelope shape. This envelope assembly is installed inside the bell gear, and the inside of the bell gear is sealed. Make a vacuum and heat it,
This is a method of manufacturing a small electron tube by heating and melting the frit glass.

However, the frit glass is made into a paste by mixing fine particles of low-melting point powder glass with a viscous organic material, and the frit glass contains a large amount of components that emit gas at high temperatures in vacuum. There is.

In the conventional method described above, organic solvents and organic materials are decomposed by heating up to 300℃ in air, and most of the decomposed gas is decomposed in the next step by heating to 350-370℃ and exhausting with a vacuum pump. The glass component contained in the powdered glass will decompose, but the glass components contained in the powdered glass will melt until the fritted glass begins to melt.
Since it will not be released from the glass unless it is heated to a temperature above 370°C, there is a drawback that sufficient degassing cannot be achieved even if it is heated below that temperature (370°C) and evacuated. In addition, in the case of a method in which the spacing between electrode leads is used or the surface of the fritted glass is made uneven to form a gas passage that penetrates the inside and outside of the display tube, the electrode leads have a thickness of at most 30 to 50 μm. The thickness of the fritted glass formed by this method is several hundred micrometers at most, so the gas passage that penetrates the inside and outside of the container is narrow and the exhaust resistance is large, and the exhaust capacity is small, and it is extremely difficult to create a high vacuum of 10 ^-6 Torr. Furthermore, as mentioned above, the gas contained in the frit glass begins to emit carbonized gas, mainly consisting of CO ₂ , from around 380°C, and as the temperature rises, the amount of gas released increases. However, at around 380°C, the temperature at which gas release begins, gas release continues for several hours even after the vacuum is drawn. Therefore, even in the conventional process of raising the temperature to 370°C, the gas is not completely exhausted. Therefore, since the tube is heated to 450° C. and sealed before gas evacuation is completely completed, there is a drawback that a fluorescent display tube with a poor degree of vacuum is produced.

Therefore, the present invention improves the above-mentioned drawbacks by completely pre-firing and reducing the exhaust resistance of the generated gas, based on the knowledge of gas release characteristics through gas release experiments of fritted glass, and makes high vacuum evacuation easier. It is an object of the present invention to provide a method for manufacturing a fluorescent display tube without an exhaust pipe.

The gist of the present invention is to provide a step of applying a sealing material mainly composed of frit glass to a sealed portion of a glass component constituting an envelope of a fluorescent display tube, and a step of applying the sealing material to a sealed portion of a glass component constituting an envelope of a fluorescent display tube. A step of pre-firing at a temperature higher than the softening point of the material, and assembling the void forming material formed of the void forming material made of low melting point glass and having a softening point higher than the softening point of the sealing material and the glass component. A method for manufacturing a fluorescent display tube, comprising the steps of forming an envelope with a cavity, and sealing the envelope with a cavity by heating and melting it in a vacuum to a temperature higher than the softening point of the cavity forming member. .

The details of the present invention will be described below with reference to an embodiment shown in the drawings. FIG. 3 is a longitudinal cross-sectional view of a fluorescent display tube formed by the manufacturing method of the present invention, showing only the envelope and omitting internal electrodes. 11 is an insulating substrate made of glass material. A side plate 12 is formed at right angles around the surface of this insulating substrate 11 with a sealing material 13a of crystalline glass interposed therebetween. Inside the side plate 12, a void forming material 1 made of low melting point glass is provided.
4 are arranged. On the top surface of the side plate 12,
Front plate 1 via a sealing material 13b of amorphous glass
5 are arranged.

A fluorescent display tube having such a structure is manufactured by the following steps. As shown in FIG. 4, the substrate 11 is formed by cutting soda lime glass, which is used for window glass, for example, and then stacking wiring, an insulating layer, an anode conductor, and a phosphor layer. , the formation method is the same as the conventional method, so it will be omitted. A crystalline glass sealing material 13a, which is a mixture of crystalline glass powder and a vehicle such as terpineol or ethyl cellulose, is printed around this substrate 11 by a seal printing method. The printed board 11 is
After heating at 150℃ in the air for about 1 hour, further heating at 300℃
After heating at 380℃ for about 10 minutes, pre-baking at approximately 500℃ in CO ₂ to prevent deterioration of the cathode and phosphor. Next, as shown in FIG. 5, the side plate 12 is assembled in a grid shape using a sealing material 13a of crystalline glass, and
is welded to. A high softening point oxide solder, such as LS-0206, is applied to the upper seal part of this side plate 12.
(manufactured by Nippon Electric Glass Co., Ltd., softening point: about 410° C.) or the like is applied as a sealing material 13b of amorphous glass. Thereafter, the sealing material 13b is preliminarily fired for 1 to 2 hours at a temperature higher than the softening point of the sealing material 13b (for example, 450 to 550 DEG C.) in a vacuum to sufficiently degas the vehicle and the amorphous glass.

On the other hand, the front plate 15 is formed by cutting soda lime glass, and after seal-printing the sealing material 13b of amorphous glass around it, baking it at 400 to 550°C in the air, and then heating it at 450 to 550°C in vacuum. Pre-bake for about 1 to 2 hours. The gap forming material 14 is arranged between the substrate 11 and the front plate 15 so that the pre-fired amorphous glass sealing material 13b of the front plate 15 and the amorphous glass sealing material 13b of the side plate 12 face each other. established,
Assemble as shown in Figure 5. Secure the assembled envelope with clips, etc. so that pressure is applied from above and below. The assembled envelope contains the void forming material 1
4, a gap 16 is formed between the front plate 15 and the side plate 12. This assembled envelope is placed in a bell gear, and the inside of the bell gear is evacuated using a vacuum pump to create a high vacuum state of about 10 ^-6 Torr, and heated, and the cathode is lit at 400°C.
Activate the oxide electrode. Thereafter, when the air is evacuated and heated to 450 to 550°C, since the softening point of the void forming material 14 of low melting point glass is 450 to 550°C, it gradually softens and the void becomes gradually narrower due to pressure from above and below. The material of the void forming material 14 is selected so that its softening point Ts is always higher than the softening point of the amorphous glass sealing material 13b, preferably its working point (400 to 500° C.), by an appropriate temperature. When the gap forming material 14 begins to melt and deform to eliminate the gap 16, the sealing material 13b has melted to a working state sufficient for sealing, so that sealing is fully possible. Once the sealing is complete, adjust the heating temperature to a temperature gradient that can sufficiently alleviate the thermal distortion of the glass, gradually cool it down, return the vacuum in the bell jar to normal pressure, take it out, and if necessary, blow the getter to reduce the vacuum inside the tube. After increasing the temperature further, an aging process is performed to complete a fluorescent display tube without an exhaust pipe.

In FIG. 6, there is no side plate 12, and the board 11 and
This is another embodiment in which the envelope is constructed of a flat-bottomed boat-shaped front container 17, in which a sealing material 13b of amorphous glass is disposed at the sealed portion of the substrate 11 and the front container 17, and a gap forming material 14 is provided. It is a sectional view in which
This is an example of assembling with a gap 16 formed, evacuation and sealing in a bell jar.

FIG. 7 shows that a groove 17a is bored in the front container 17,
This is another embodiment in which a gap forming material 14 is disposed within this groove to form a gap 16. In this embodiment, the molten void-forming material 14 flows into the groove 17a and does not flow into or out of the tube, resulting in a clean finish.

In the embodiment shown in FIG. 8, the gap forming material 14 is disposed on the upper surface of the substrate 11 so as to be located outside the side plate 12. In the embodiment shown in FIG. In this way, by disposing the gap forming material 14 on a member where the side plate 12 is not disposed, it can act as a guide so that the sealed portion of the substrate 11 and the front container 17 does not shift, and the upper and lower seals can be This has the effect that the attached parts are sealed together without shifting.

As explained above, the present invention applies a sealing material containing glass as a main component to the sealing parts of glass members such as the substrate side plate and front plate of a display tube, and after pre-baking, the low melting point glass is applied. This method involves adding a gap-forming material, assembling, and heat-sealing in a vacuum, so it has the following effects. Since the fluorescent display tube has a gap formed in the bell jar until just before sealing, the exhaust resistance can be reduced, the baking effect can be made more efficient, and high vacuum exhaust can be easily performed. Furthermore, the glass parts are thoroughly pre-fired to reduce the amount of gas generated in the sealant as much as possible, so there is almost no gas released during sealing during the bell jar, making it easy to make display tubes without chip tubes. It has an excellent feature of being able to provide highly reliable fluorescent display tubes in a vacuum with a high yield, and its effects are extremely large.

Furthermore, the present invention is not limited to the above-described fluorescent display tube, but can also be applied to display tubes such as discharge display tubes and plasma displays that utilize gas discharge. The display tube that uses gas discharge has a rare gas such as Ar gas or Ne gas in the vacuum envelope.
Gas, etc. is sealed in the vacuum container, but if the structure eliminates the chip tube, the rare gas would have to be introduced from between the components of the envelope in the vacuum container, but in the conventional method, the gaps were small and it was difficult to enter the rare gas. In the present invention, since gaps are formed between the members by the gap-forming material, there is an effect that rare gas can be easily introduced. Therefore, it has the excellent effect of being able to provide highly reliable gas discharge display tubes, plasma displays, etc. with excellent display quality.

[Brief explanation of drawings]

Figures 1 and 2 are external diagrams of conventional fluorescent display tubes.
FIG. 3 is a sectional view of one embodiment of the present invention, FIG. 4 is a plan view of a substrate of the same embodiment, and FIGS. 5 to 8 are sectional views showing the assembled state of the present invention. 11...Substrate, 12...Side plate, 13...Sealing material, 14...Gap forming material, 16...Gap.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a display tube provided with an airtight envelope for accommodating electrodes such as an anode and a cathode, the envelope being constituted by a plurality of members, a step of applying a sealing material containing glass as a main component to the sealing portion of the member; and a step of pre-firing the member to which the sealing material is applied at a temperature higher than the softening point of the sealing material. , a space made of low melting point glass and whose softening point is higher than the softening point of the sealing material of the final sealing part.
a step of previously forming a cavity between the members using a forming material; and a step of sealing the envelope member with a cavity by heating and melting the cavity member in a vacuum container to a temperature higher than the softening point of the cavity forming member. A method for manufacturing a display tube, comprising: 2. The method of manufacturing a display tube according to claim 1, wherein the glass that is the main component of the sealing material is amorphous glass, and the preliminary firing is performed in a vacuum. 3. The method of manufacturing a display tube according to claim 1, wherein the glass that is the main component of the sealing material is crystalline glass, and the preliminary firing is performed in the atmosphere. 4. The method for manufacturing a display tube according to claim 1, 2, or 3, wherein the envelope member is a plurality of glass members. 5. Claim 1 or 2 or 3 or 4, wherein the display tube in which the envelope member is placed in a vacuum container and heat-sealed in a high vacuum atmosphere is a fluorescent display tube. 2. Method for manufacturing a display tube as described in Section 1. 6. Claims 1, 2, or 3, wherein the display tube in which the envelope member is placed in a vacuum container and heat-sealed in an ionized gas atmosphere is a display tube that utilizes gas discharge. 4. The method for manufacturing a display tube according to item 4.