JPH0436929A - Manufacture of electron tube - Google Patents

Abstract

PURPOSE:To prevent crack initiation at a chipped-off part by heating the exhaust device side portion of an exhaust pipe, which lies inside of a heater coil, to a high temp. relative to the electron tube body side portion, melting that portion, and thereby lessening a projection likely to be generated when the molten glass is sucked to the electron tube body side. CONSTITUTION:A heater coil 30 to be arranged around an exhaust pipe 28 is wound tightly, and a taper is provided so that the coil dia. DU on the color image-receiving tube body side is larger than the coil dia. DL on the exhaust device side. If this heater coil 30 for chipping off the exhaust pipe 28 of glass upon melting it is formed tapered, the exhaust pipe portion lying inside of this heater coil 30 is so heated that its exhaust device 31 side nearer the coil gets higher temp. that the color image-receiving tube body side further from the coil and is melted and chipped off quickly. This chipping-off with melting spreads gradually to the color image-receiving tube body side.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an electron tube, and in particular, to a method for manufacturing an electron tube, and in particular, a method for producing a tip-off shape in the exhaust process of a color picture tube, etc., which uses a glass exhaust pipe. The present invention relates to a method of manufacturing an electron tube with good quality.

(Prior Art) For example, in a color picture tube, various internal features such as a phosphor screen, a shadow mask, an inner silt, and an internal conductive film are arranged inside an envelope consisting of panels and funnels that are joined together. The electron gun is further sealed in the neck of the funnel and then evacuated.

The electron gun is sealed by inserting the electron gun into a predetermined position inside the neck, then heating and welding the flared part of the stem with a glass exhaust pipe attached to the electron gun and the neck part opposite to this flared part. It is done by doing. Then, for exhaust, an electric heating coil 1) shown in Fig. 4 is placed around the exhaust pipe coaxially with the exhaust pipe, and
The distal end side of the exhaust pipe (2) is connected to an exhaust device 17 to exhaust air, and the electric heating coil (1) generates heat by energizing the exhaust pipe portion located inside the electric heating coil (1) as shown by the dashed line. After melting and tipping off, the molten part (
3) is located at the position not indicated by the broken line (4) and is not separated.

By the way, color picture tubes are required to have larger exhaust conductance in order to improve productivity, quality, and reliability as they become more and more popular as dolls.

Is it possible to increase this exhaust conductance by increasing the exhaust pipe diameter that determines it?
As shown in Figure 5, the outer diameter of the stem is 7.
The outer diameter DI" of the 177 part (6) is determined by the inner diameter of the neck of the funnel, and around the exhaust pipe (2) provided in the center of the flare part (6), there is a binder circle determined by international unified standards. Attach multiple lead pins (7
), there is a limit to the expansion of the outside diameter of the exhaust pipe, and it is not possible to attract many people.

Another method 7 is to relatively enlarge the inner diameter dE of the exhaust pipe (2), but if the inner diameter dE is enlarged, the wall thickness of the exhaust pipe (2) becomes thinner, as shown in Fig. 6. As shown in the figure, the molten glass is sucked into the main body of the color picture tube due to the heat generated by the electric heating coil (1), and the protrusion (9) that extends L (E) becomes too large, and this protrusion (9) and the exhaust pipe (2) A deep V-shaped groove (10) is formed between the chip and the inner wall, which makes it easy for cracks (11) to occur in the chip-off area.

In severe cases, as shown in Figure 7, a protrusion (9
) extends greatly and tilts, and comes into contact with the inner wall of the exhaust pipe (2), causing a crack (11) to form at the contact area.

Furthermore, when speeding up the exhaust process for the purpose of improving productivity, the heating time by the electric heating coil becomes shorter accordingly. In order to achieve the required chip-off in such a short heating time, it is necessary to increase the heating temperature. However, 7. When the heating temperature of the electric heating coil is increased, the temperature difference between the molten part (3) and the part adjacent to this molten part (3) increases, and as shown in Fig. 4, the molten part (3) The outer diameter of the adjacent part (12) changes gradually, or as shown in Fig. 8, the outer diameter changes sharply, and in this case, the protrusion (9) due to suction
If the tip-off portion becomes too large, a deep V-shaped groove (10) is formed between the protrusion (9) and the inner wall of the exhaust pipe (2), and cracks (11) are likely to occur at the tip-off portion.

(Invention or problem to be solved) As mentioned in item 1, when the inner diameter of the glass exhaust pipe is increased in order to increase the exhaust conductance of an electron tube such as a color picture tube, the wall of the exhaust pipe becomes thicker or thinner. , the protrusion that occurs when the molten glass is sucked into the color picture tube body side due to the heat generated by the electric heating coil becomes excessive, and a deep V-shaped groove is formed between this protrusion and the inner wall of the exhaust pipe, resulting in tip-off. Cracks are more likely to occur in parts. In extreme cases, the protrusion may extend greatly and tilt, making contact with the inner wall of the exhaust pipe and causing cracks to occur at the contact area.

In addition, when speeding up the exhaust process for the purpose of improving productivity, the heating time by the electric heating coil (1) is shortened, so the heating temperature is increased to perform the required tip-off in that short heating time. There is a need. However, when the heating temperature of the electric heating coil is increased, the temperature difference between the molten part and the part adjacent to this molten part becomes large, and the change in outer diameter between the molten part and the adjacent part becomes steep, and in this case as well, protrusions due to suction occur. If the protrusion becomes too large, a deep V-shaped groove is formed between the protrusion and the inner wall of the exhaust pipe, and cracks are likely to occur at the tip-off portion.

This invention has been made in view of the problems described in ``-'', and when the glass exhaust pipe of an electron tube is heated and melted by the heat generated by the electric heating coil and is tipped off, the molten part that is heated and melted by the electric heating coil and the molten part. The purpose is to prevent cracks from occurring in the tip-off part by making the outer diameter change gradually with the adjacent part and reducing the size of the protrusion that occurs when molten glass is sucked into the electron tube body.

[Structure of the invention] (Means for solving the problem) An electric heating coil is arranged around a glass exhaust pipe installed in the electron tube body, and the exhaust pipe portion located inside the glass exhaust pipe is melted by this electric heating coil. In the manufacturing method of an electron tube, in which the electron tube body is tipped off by chipping off the electron tube body, C1 the diameter of the coil on the electron tube body side of the above-mentioned electric heating coil is made larger than the coil diameter on the exhaust device side, or the winding pitch of the coil on the electron tube body side of the above-mentioned electric heating coil is The winding pitch of the coil on the device side is made coarser than the winding pitch of the coil on the device side, and the part on the exhaust device side of the exhaust pipe located inside this electric heating coil is heated to a relatively higher temperature than the part on the side of the main body of the electric heating coil. Made the exhaust pipe tip-off.

(Function) When a glass exhaust pipe is heated and melted using an electric heating coil with the above coil diameter or winding pitch, the outer diameter change between the melted part inside the electric heating coil and its adjacent part can be smoothed, and the melted It is possible to reduce the protrusion that occurs due to the glass or electrons (i) being sucked into the main body side, and to avoid contact with the inner wall of the exhaust pipe.

(Example) The present invention will now be described based on an example with reference to the drawings.

FIG. 1 shows, as an example, an evacuation step in a method of manufacturing a color picture tube.

Generally, in manufacturing a color picture tube, a fluorescent image (21) consisting of a dot-shaped or striped three-color phosphor layer is formed on the inner surface of a panel (20), and a shadow mask (22) is attached to the inner surface of the fluorescent image (21). , and this shadow mask (22)
Take the inner shield (23) into the panel (20) on which the various pipe internal materials are arranged, and insert it into a funnel-shaped funnel (25) with an internal conductive film (24) formed on the inner surface.
After that, the electron gun (27) is inserted into the glass neck (26) of the funnel (25), and the glass exhaust pipe (=J stem) attached to the electron gun (27) is inserted into the glass neck (26) of the funnel (25). and the neck (26) are welded to seal the electron gun (27).Then, attach the exhaust pipe (28) to the wall of the exhaust pipe (28) near the main body of the color picture tube so that it is coaxial with the exhaust pipe (28). An electric heating coil (30) is placed in the exhaust pipe (28), and the distal end of the exhaust pipe (28) is connected to the exhaust device (31).The inside of the pipe is evacuated to a high vacuum, and the electron gun ( 26) After activating the cards that make up the
It is manufactured by melting and tipping off the exhaust pipe portion located inside the first electric heating coil (30) by energizing and generating heat.

By the way, in the color picture tube manufacturing method of this example, the electric heating coil (30
) is formed in the structure shown in FIG.

That is, the coil is tightly wound, and the coil diameter DU on the color picture tube main body side is 1. The coil diameter D on the device side is 1. It is formed into a larger tapered shape.

When the electric heating coil (30) for melting and tipping off the glass exhaust pipe (28) is made into a tapered shape, the exhaust pipe portion located inside the electric heating coil (30) is far from the coil. The exhaust device (31) side, which is closer to the coil than the color picture tube body side, is heated to a high temperature and melts quickly to cause tip-off, and the melted tip-off gradually extends toward the color picture tube body side. . Therefore, the outer diameter of the portion melted by the electric heating coil (30) and the adjacent portion on the color picture tube main body side is relatively gradual. Therefore, not only conventional exhaust pipes with thick walls, but also exhaust pipes with thin walls to increase exhaust conductance, the protrusion (32a) that is created due to the suction of molten glass is made smaller. This makes it possible to prevent cracks at the chip-off portion, which conventionally occur due to excessive protrusions. Furthermore, similar results can be obtained even if the heating temperature of the electric heating coil (30) is higher than usual in order to improve productivity.

In this case as well, since the exhaust device (28) side is heated to a high temperature, a large protrusion (32b) is formed due to suction, but this exhaust device (28) side is a part that is to be cut off and discarded after sealing. ,No problem.

Next, other embodiments will be described.

In the first embodiment, the electric heating coil is set to the coil diameter DO on the color picture tube main body side or the coil diameter DI on the exhaust device side.

Either the coil diameter is kept constant and the winding pitch Pv of the coil on the color picture tube body side is coarser than the winding pitch Pv of the coil on the exhaust device side, as shown in Fig. 3. Similarly to the above embodiment, the exhaust device side can be heated to a higher temperature than the color picture tube body side to quickly form the melting part 11'', and the protrusion (32a) produced by the suction hole on the color picture tube body side can be removed. By making the size smaller, cracks in the sealed portion can be prevented.

Furthermore, by combining the above embodiments, the coil diameter DtJ on the color picture tube body side of the electric heating coil is made into a tapered shape larger than the coil diameter DI on the exhaust device side, and the coil on the color picture tube body side is wound. When the pitch Pv is made coarser than the winding pitch Pv of the coil on the exhaust device side, the degree of freedom in designing the electric heating coil increases, and a more practical and optimal electric heating coil can be obtained.

Although the above embodiments have been described with respect to a method of manufacturing a color picture tube as an example of an electron tube, the present invention can be applied to methods of manufacturing various electron tubes having a glass exhaust pipe.

[Effects of the Invention] The diameter of the electric heating coil for heating and melting the glass exhaust pipe attached to the electron tube body to seal it is made larger than that of the coil on the exhaust device side, or the diameter of the coil on the electron tube body side is If the winding pitch is made coarser than the winding pitch of the coil on the exhaust device side, the outer diameter change between the melted part by the electric heating coil and the adjacent part on the electron tube body side is smoothed out, and the molten glass is sucked into the electron tube body side. The resulting protrusion can be made small and contact with the inner wall of the exhaust pipe can be avoided. Therefore, it is possible to obtain a crack-free tip-off even with a relatively thin exhaust pipe, and for electron tubes where the outer diameter of the exhaust pipe cannot be increased, it is possible to increase the exhaust conductance by expanding the inner diameter of the exhaust pipe. Therefore, it is possible to improve the pumping speed and the degree of vacuum inside the tube, and it can be applied to, for example, a large color picture tube to improve its productivity and quality. In addition, even when applied to electron tubes with conventionally used thick exhaust pipes, a good tip-off shape can be obtained, making it possible to speed up exhaust.

[Brief explanation of the drawing]

Figures 1 to 3 are detailed explanatory diagrams of this invention.
The figure is a diagram for explaining an evacuation method for a color picture tube, which is one example of the method, Fig. 2 is a diagram showing the structure of an electric heating coil that melts and tips off the exhaust pipe after evacuation, and Fig. A diagram showing another structure of the electric heating coil; FIG. 4 is a diagram showing the arrangement of the conventional electric heating coil with respect to the exhaust pipe of a color picture tube;
FIG. 5 is a diagram showing the shape of a stem for a color picture tube, and FIGS. 6 and 7 are diagrams for explaining the problems that occur when a thin-walled exhaust pipe is heated and melted using a conventional electric heating coil, respectively. FIG. 8 is a diagram for explaining problems that occur when the evacuation process is sped up. 2G...Neck, 27...Electron gun, 28
...Exhaust pipe, 30...Electric heating coil, 81
...Exhaust device, 32...Protrusion,] 2 Agent: Patent attorney Norio Ogo

Claims (1)

[Claims] An electric heating coil is disposed coaxially with the glass exhaust pipe around a glass exhaust pipe attached to the electron tube body, and the glass exhaust pipe is connected to an exhaust device so that the electron tube body is In the method for manufacturing an electron tube in which the glass exhaust pipe is tipped off by melting the exhaust pipe portion located inside the electric heating coil by energizing and generating heat in the electric heating coil after exhausting the air, the diameter of the electron tube main body side of the electric heating coil is is larger than the coil diameter on the exhaust device side, or the winding pitch of the electron tube body side coil of the electric heating coil is made coarser than the winding pitch of the coil on the exhaust device side, so that the diameter of the exhaust pipe located inside the electric heating coil is increased. A method for manufacturing an electron tube, characterized in that the glass exhaust pipe is tipped off by heating and melting the exhaust device side part at a relatively higher temperature than the electron tube main body side part.