JPS5929538B2 - Sealing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing method using a frit glass mixture for manufacturing color cathode ray tubes, fluorescent display tubes, and the like.

For example, when manufacturing cathode ray tubes, a funnel and a panel are sealed together using a fritted glass mixer (hereinafter referred to as mixer).

That is, as shown in FIG. 1, the mixture 3 is applied to the sealing end surface 2 and above of the funnel 1 as one of the members to be sealed.

This mixture 3 forms a vehicle in which, for example, 1 part of nitrocellulose or ethylcellulose is dissolved in 99 parts of an organic solvent such as amyl isoacetate or butyl isoacetate or butylcarpitol acetate, and 200 meshes are passed through this vehicle. 10 parts of fritted glass powder was added, and the mixture was kneaded to become active.

After applying the mixture 3, it is heated and dried at 130° C. for 5 to 10 minutes, and then applied to the sealed end surface 2 of the funnel 1 on the sealed end surface of the panel 4, which is the other member to be sealed. 5 is accurately aligned using a positioning jig or the like, and joined through the mixer 3, for example, 40
Heat at a high temperature of 0°C for 1 hour.

In this heating process, first, the nitrocellulose in Mixture 3 is decomposed and evaporated, and then the frit glass is melted and crystallized at 400 to 450°C, or it is slowly cooled while remaining amorphous. The sealing is completed and the envelope of the cathode ray tube is formed.

Conventionally, in such a manufacturing process, when applying a mixture relatively thickly, for example, 0.5 to 15 mm,
Since the mixed tea has a high specific gravity, for example, d: 4 to 6, a discharge drop method is used in which the sealed end surface 2 of the funnel 1 is turned upward and the mixed tea discharged from the applicator is dropped.

However, according to such a method, as shown in FIG. 2, a dent is likely to occur in the center of the mixer 3 after drying.

If there is such a recess, when the panel 4 is superimposed on the funnel 1, a space will be created in the recess.

Therefore, if the frit glass is melted and sealed in this state, the air in the space will escape, but a portion will be created where it cannot escape, forming a cavity within the frit glass layer.

In addition, if the tube is sealed while air is escaping, vent holes are formed inside or outside the tube, and further between the inside and outside of the tube.

Not only can there be ventilation holes inside and outside the pipe, but also when there is a ventilation hole on one side, there are also cases where there is no ventilation hole (
However, if the effective length of the frit glass layer is significantly reduced due to cavities, near leakage will occur in that portion, making it impossible to maintain complete vacuum tightness.

In addition, due to the decrease in withstand voltage, a through hole is created in the core due to arc heat, which may also destroy the vacuum seal.
It can destroy the cathode ray tube.

As a method for improving such defects, it is conceivable to turn the sealing end surface 2 of the funnel 1 downward and supply and apply the mixture from below.

According to such a method, the mixture is on the bottom side,
Furthermore, as mentioned above, the specific gravity of Mixture is large and heavy, for example, d: 4 to 6, so the degree of curvature of the surface becomes large, and even after drying, blood loss occurs and the above-mentioned dents do not occur. However, it is possible to obtain good results.

However, even with this method, there are restrictions on the physical characteristics of the mixture used.

For example, if the viscosity of the mixed tea is too low, mountain-shaped protrusions are formed on the surface of the mixed tea 3 as shown in FIG.

In such a state, during sealing, the accuracy of regulating the position with the panel may be hindered, or a portion with a large amount of mixture may protrude in a large amount, and a portion with a small amount of mixture may not be filled, causing vacuum breakdown.

Therefore, the applicant first proposed the sealing end surface 2 of the funnel 1.
We proposed a method in which the funnel 1 is turned downward, the mixture is supplied from below and applied, and then the funnel 1 is turned over so that the sealed end surface 2 is turned upward.

The method will be explained with reference to FIGS. 4 and 5 in the case of manufacturing a cathode ray tube.

11 is a coating device, and this coating device 11 has a container 12 that is long in the horizontal direction.

This container 12 consists of a bottom plate 13, long side plates 14 on the front and back sides, and short end plates 15 on both end faces, and further has an upper lid plate 16 attached to the front and rear parts of the upper surface, and an opening 17 between the front and rear upper lid plates 16. is formed.

A coating mechanism 21 is provided within the container 12.

In this application mechanism 21, a rotating shaft 22 is rotatably supported between end plates 15 at both ends of a container 120, and a roller 23 made of stainless steel, rubber, etc. is fixed to this rotating shaft 22. Opening 17 on the top surface of the container 12
It is slightly protruding from the surface.

A driving gear 2 is attached to a protrusion on one side of the rotating shaft 22.
A drive device (not shown) is connected to this gear 24, and the roller 23 is rotated together with the rotating shaft 22.

Further, a roller 2 is provided inside the side plate 14 on the front side of the container 12.
A thickness regulating piece 25 is attached to the circumferential surface of the container 12 via a support mechanism 26 so as to be freely adjustable forward and backward.
A residue scraping piece 27 is attached to the inner side of the rear side plate 14 with respect to the circumferential surface of the roller 23 via a support mechanism 28 so as to be adjustable in forward and backward movement.

A transfer device 31 is disposed above the coating device 11.

In this transfer device 31, suspension devices 33 are movably provided on a rail 32 at predetermined intervals.

Further, a support stand 34 is provided below the rail 32 up to the coating device 11 section.

Then, the mixture 3 is placed in the container 12 of the coating device 11.
is injected and stored so that the lower part of the roller 23 is submerged and in contact with it.

Then, when the roller 23 is rotated in the direction of the arrow, the mixture 3 adheres to the roller 23, is drawn up, and rises.

This is scraped off at the tip of the thickness regulating piece 25 so that the mixed tea film 3a has a desired thickness, thereby regulating the amount of the mixed tea film 3a that adheres to the roller 23 and moves up.

On the other hand, one of the funnels 1 as a member to be sealed is held by the neck part of each suspension device 33 of the transfer device 31 and suspended with the sealed end surface 2 facing downward. It moves along the rail 32 in the direction of the arrow along the support stand 34.

Then, when the funnel 1 is placed on the roller 23 coated with the mixed tea film 3a, its sealed end face 2 comes into contact with the mixed tea film 3a, and this mixed tea film 3a adheres to the sealed end face 2.

In this case, it is preferable to set the sealing end surface 2 of the funnel 1 at a position slightly above the upper outer circumferential surface of the roller 23 so that it bites into the mixture film 3a by about 0.05 to 0.5 mm.

Note that the rotational speed of the roller 23 is determined by setting the peripheral speed of the roller 23 to be the same as the feeding speed of the funnel 1, so that the peripheral speed of the mixer at the position corresponding to the sealed end surface 2 of the funnel 1 is set to be the same as the feeding speed of the funnel 1. The thickness of the mixture applied to the sealing end surface 2 of the can be made most uniform.

Next, as the roller 23 rotates, the excess mixed tea 3 adhering to the roller 23 is removed by the residue scraping piece 27, merges with the mixed tea 3 in the container 12, and moves up again by the roller 23.

In this way, after applying the mixed chatter 3 with the sealed end face 2 of the funnel 1 facing downward, the funnel 1 is turned over and the sealed end face 2 is turned upward within the time that the applied mixed chat 3 does not dry. do.

As a result, the protruding portion of the mixture 3 that appears downward is lowered by its own weight and surface tension, sinks into the nearby mixture layer, and becomes flush with the protrusion.

The surface of the frit glass after drying has little curvature and becomes nearly flat as shown in FIG.

After applying the mixed cha 3 and drying it in the same manner as before, the sealed end face 5 of the panel 4, which is the other member to be sealed, is placed on the sealed end face 2 of the funnel 1 using the mixed cha 3. The tubes are bonded together through a tube, heated and sealed, and then subjected to a cooling process to form the envelope of a cathode ray tube.

Although the method described above allows the mixture to be applied uniformly over almost the entire surface, the apparatus described above has the following problems.

(1) The sealed end surface 2 of the funnel 1 is coated with the mixture 3 in a state parallel to the rotating shaft 22 of the roller 21, and as shown in FIG. Immediately before leaving the tea 3, the mixed tea 3 adhering to the funnel 1 remains on the roller 21 and is pulled by the mixed tea 3 trying to leave, and as a result, the rotating shaft 22 of the roller 21
In the two sides on both sides where the mixer 3 is fed at right angles to the funnel 1, there is no problem because the mixer 3 has a symmetric cross section with respect to the inner and outer surfaces of the funnel 1, but in the two sides on the front and back, as shown in FIG. In this case, the mixed tea 3 is pulled backward and lateral in the feeding direction and dries without returning to the center, and when this happens, the mixed tea 3 is biased toward the thicker side during sealing.

That is, as shown in FIG. 9, among the front and rear sides of the funnel 10, the mixer 3 is on the inside on the leading side, and on the trailing side, the mixer 3 is on the outside, protruding from the side of the cathode ray tube.

On the contrary, on the opposite side, that is, on the side with less amount of mixer 3, the sealed portion between the funnel 1 and the panel 4 cannot be filled.

In such a state, the cathode ray tube is likely to be destroyed due to the substantial reduction in the bonding area and the formation of sharp corners.

In addition, the length in the outside and outside directions of the tube is small (as a result, the insulating force decreases, it cannot withstand high voltage differences between the inside and outside of the tube, and dielectric breakdown is likely to occur).

(2) In order to apply a certain amount of mixed tea, for example 0, 6 mtttJJ, it is essential to have a high viscosity of the mixed tea.
In order to make it more than m, it is necessary to use a mixture with a viscosity of more than 10,000 centipoise.

Then, increase the viscosity of the mixture (the more
The speed at which the new mix 3 in the container 12 enters the mix char 3 that has adhered to the funnel 1 on the roller 21 and has become dented is slowed down, and the returned mix char 3 and the mix char 3 in the container 12 are The contact angle with the mixed cha 3 becomes acute, and in either case, the mixed cha 3 on the roller 21 becomes insufficient, resulting in a partial decrease in the amount of coating, or it eats up air bubbles, resulting in an uneven coating state. It happens.

Moreover, air bubbles remain even after sealing and reduce the withstand voltage.

For these reasons, it is not possible to increase the coating speed too much.

In addition, as mentioned above, increase the viscosity of the mixed tea (then the high viscosity mixed tea will be difficult to move in the container 12, that is, it will not mix easily, so when replenishing the mixed tea, the new mixed tea to be replenished will be Naturally, the physical properties of the mixture will differ due to drying and changes over time.
The mixer in the container 12 and the newly replenished mixer are difficult to mix in a short period of time (If the two cannot be used together, the composition of the old mixer will continue to change and the coating characteristics may partially change on the roller. This causes uneven application of the mixture.

(3) When using funnels or panels with poor flatness where the sealing surface is not polished, it is necessary to increase the amount of application.
Depending on the degree, shortages may occur.

However, when the amount of mixed tea applied is large, the amount of mixed tea that drips from the funnel once applied is large, resulting in large material loss.

The present invention has been made in view of the above-mentioned points, and an object of the present invention is to prevent uneven application of the mixture and to uniformly apply the mixture over the entire surface.

Next, one embodiment of the present invention will be described with reference to FIG.

A first coating device 41a, a first drying device 42a, a direction changing device 43, a second coating device 41b, and a second drying device 42b are arranged in series.

The first coating device 41a and the second coating device 41b
is shown in FIGS. 4 and 5 above.

Then, the funnel 1 is transferred to the first coating device 41.
Mixture 3 is applied to the sealed end surface 2 of the funnel 1 in step a, and then sent to the first drying device 42a to be dried.
Furthermore, it is sent to a direction changing device 43 to reverse the front and rear directions.

That is, the leading side and the trailing side of the funnel 1 are reversed.

Next, the funnel 1 is further transferred, and the mixture 3 is again applied to the sealed end surface 2 of the funnel 1 by the second application device 41b, and then dried by the second drying device 42b.

Then, the sealing end surface 2 of the funnel 1 is joined to the sealing end surface 5 of the panel 4 which is in contact with the funnel 1 via the mixer 3.

In the above process, the first application of mixed tea is performed with the sealing end surface 2 of the funnel 1 facing downward, and then the funnel 1 is inverted and the first drying is performed with the coated surface of the mixed chat facing upward. Then, the funnel 1 is turned over and the sealed end surface 2 faces downward to apply the mixture for the second time, and the second drying is performed as it is.
After the second application of the mixed tea, the funnel 1 is inverted and the second drying is performed with the mixed tea application surface facing upward.

Note that the entire process may be performed with the sealed end surface 2 of the funnel 1 facing upward.

The target application amount of the mixture on the sealed end surface 2 of the funnel 1 is the sum of the first and second application amounts, so each application amount is small (in this case, the first application amount is The ratio of the amount of application and the second application may be freely selected.

Note that when performing the second application, since the mixture has already been applied to a certain thickness in the first application, the sealing end surface 2 of the funnel 1 is applied to that thickness or slightly less. is released from the roller 21.

According to such a method, the mixture cannot be shifted as shown in FIG.

In other words, on the side where the roller 210 is sent parallel to the rotating shaft 22 to be coated, a tendency as shown in Fig. 8 occurs in the first coat, but since the coat is divided into two coats, the coating is applied in one coat. Since the amount is small, the amount of deviation will be small.

Furthermore, by performing the second application with the leading side and the trailing side facing in opposite directions, the second application is offset in the opposite direction to the offset that occurred during the first application.

Therefore, the two offsets cancel each other out and are resolved as shown in FIG. 11.

In the figure, the dotted line inside the mixture 3 is drawn for convenience to show the first and second coating states, and is not visible in the actual cross section.

Moreover, the problem of off-centering does not occur on the side where the roller 210 is fed perpendicularly to the rotating shaft 22 and coated.

In addition, if the mixture is made to be particularly thick, no dents will occur.

In other words, by reducing the amount of the first coating, the curved surface of the applied mixture is small, and the difference in effective surface area that contributes to drying is small between the center and both sides, and the amount of coating is small, so the drying process is reduced. There is almost no difference, and the second application did the same (no dents were formed).

Furthermore, since the amount of coating per time in the first and second coating can be reduced, for example, each half of the target coating amount is sufficient, so the viscosity of the mixture can be significantly lowered.

There are various ways to adjust the amount of coating other than regulating the viscosity, but when applying a particularly thick coating, a high viscosity is usually an essential condition, but the coating is divided into two coats. This can also be achieved with a viscosity of 1/10 or less.

As a result, the speed of replenishing the traces of mixcha lost during application on the roller is more than five times faster, and the contact angle between the mixchae that returns (returns) and the mixchae inside the container increases (becomes larger). Therefore, there is no possibility of air bubbles being trapped or insufficient supply of mixture.

Therefore, the coating speed can be further increased significantly, for example by a factor of five.

Furthermore, since a low-viscosity mixer can be used, the remaining mixer in the container and the replenishing mixer can easily mix together in a short time, making it possible to improve uneven coating due to insufficient mixing.

In addition, the viscosity of the mixed tea applied to the funnel is more likely to be small than that of high viscosity, but under certain constraint conditions, if the time to dry or the time to turn over is long, the difference is relatively small. The influence of the amount applied in one application is greater than that.

Therefore, by applying the product in two times, the amount of application per time is small, so there is less dripping.

(In addition, in the second application, some of the solvent is absorbed into the mixture applied in the first application, so there is no dripping, and therefore the material used for dripping is saved. can.

Furthermore, the amount of mixture applied can be increased.

That is, there is almost no effect even if the amount of application is increased by about 50%.

In addition, if the mixture does not shift as described above, for example, if the width of the application area is small, the amount of application is extremely large (or if a slow-drying vehicle is used, The direction of the funnel may be reversed for the second application.

In addition, in the case of a mixture using a solvent vehicle with a relatively fast drying rate, it is possible to lengthen the funnel feed line (to dry naturally) after the first and second coats without using a drying device. You can also do this.

Next, an example of the process will be described with reference to FIGS. 12 and 13.

A, , A2...... are funnels before application of mixcha, B, , B2......
is the funnel after the first coating, cl, C2... is the funnel after the second coating, and 41 is the mixture coating device.

In the case of Fig. 12, first funnel A, , A2・°
.

After this first application, funnel B1.
B2...... is the uncoated funnel A1 after passing through the drying process. It is placed in the middle of A2...... and transported.

Then, a second application is performed through the same application device 41 and the same location as before.

Funnels C1 and C2 after this second application...
. . . exits from the coating path and is sent to the bonding process with the panel.

In this case, funnels C1 and C after the second application
2... may be performed in the same place as the drying of the first application, and taken out halfway.

In the case of FIG. 13, the coating section of the coating device 41 has a width sufficient to coat two funnels at the same time.

And funnel A before application of mixcha, ,
In A2, the first coating is carried out passing near one end of the coating section, and the second coating is carried out passing near the other end of the coating section after a drying process.

Incidentally, a reversing device or a direction changing device is disposed in the middle of the route shown in FIGS. 12 and 13 as necessary to perform vertical reversal and forward/backward reversal.

By doing this, it is possible to apply two times in succession with one coating device, and the main part of the device can be made smaller. Since the funnel can be supplied without leaving any space, the coating efficiency can be improved.

In addition, if the coating is to be carried out by hand or in half-time, the first coating may be performed, the coating may be removed once to dry, and then the second coating may be carried out all at once.

In the above description, the case where the mixture is applied twice has been described, but it is of course possible to apply the mixture three times or more.

However, if the coating is applied three times or more, the process becomes more complicated and losses increase accordingly, so two coatings are usually appropriate.

Further, the method of applying the mixture is not limited to the method using a roller, but may be any suitable method such as a stamp application method or a belt application method.

Furthermore, in each of the above-mentioned embodiments, the case where the cathode ray tube, that is, the funnel and the panel are sealed with a mixture, has been described. For example, the base glass and cover glass of a flat fluorescent display tube are sealed with a mixture. It can be widely used in the manufacture of articles such as glass tubes.

According to the present invention, it is possible to apply the mixture uniformly over the entire surface without unevenly applying the mixture (and preventing the formation of depressions on the application surface), and also to increase the application speed and prevent dripping. etc., and materials can be saved.

In addition, by changing the direction of the mixed material on the parts to be sealed between the first and second times, it is possible to apply the mixed chatter to a thicker layer (even when applying it, the unevenness of the application can be prevented). It can be prevented.

Furthermore, by performing the first and second application of the mixed tea in the same application section, and further by performing the application of the mixed chatter in parallel in the same application section, The main parts of the device can be made smaller and management becomes easier.

[Brief explanation of drawings]

Figure 1 is a perspective view of the funnel and panel of a cathode ray tube, Figures 2 and 3 are cross-sectional views showing the conventional application state;
Fig. 4 is a sectional view showing an embodiment of the coating device, Fig. 5 is a partially cutaway perspective view, Fig. 6 is a sectional view showing its coating state, and Fig. 7 is the coating shown in Fig. 4. A cross-sectional view of a part of the device,
FIG. 8 is a sectional view showing the applied state, FIG. 9 is a sectional view of the sealed state, and FIG. 10 is a plan view showing an embodiment of the present invention.
FIG. 11 is a sectional view showing the coating state by the method of the present invention;
FIGS. 12 and 13 are plan views showing other embodiments of the present invention. 1...Funnel as one member to be sealed,
2...Sealed end face, 3...Frit glass mixture, 4...Panel as the other member to be sealed, 5...Sealed end face , 4L41a, 4
1b...-Coating device.

Claims (1)

[Scope of Claims] 1. After applying a frit glass mixture to the sealed end face of one of the members to be sealed and drying, apply a frit glass mixture again on the applied frit glass mixture, and then . A sealing method, characterized in that the sealing end face of the one member to be sealed is joined to the end face of the other member to be sealed. 2. The sealing method according to claim 1, wherein the first and second applications of the frit glass mixture to the members to be sealed are performed by changing the orientation of the members to be sealed. . 3. Applying the frit glass mixture at the application section while transporting the members to be sealed at intervals, and arranging the members to be sealed at the above-mentioned intervals, which have been coated for the first time,
2. The sealing method according to claim 1, wherein the second application is performed in the same application area as the first application. 4 Using a coating device that has a coating section that can coat two members to be sealed in parallel with a frit glass mixture,
2. The sealing method according to claim 1, wherein the first application is performed at one position of the application section, and the second application is performed at the other position.