JP2000021311A - Manufacture of electron tube and its device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an electron tube which has a a long service life and is difficult to leak. SOLUTION: A glass tube 15 is evacuated with an electrode assembly 10a inserted therein from an end thereof. The glass tube 15 is sealed at its one by heating the circumference of a glass member 12 of the electrode assembly 10a from the outside by an electric heater 5a and melting the glass tube 15 and the glass member 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for manufacturing an electron tube in which a lead is sealed at an end of a glass tube and an electrode is connected to a tip of the lead.

[0002]

2. Description of the Related Art A cold cathode fluorescent tube is an example of this type of electron tube. Since this cold cathode fluorescent tube is excellent in miniaturization and weight reduction, it is widely used as a backlight of a liquid crystal display panel. In addition, the cold cathode fluorescent tube is also used as a light source of an information board used for providing various kinds of information to a user in a store or a station.

FIG. 6 is a sectional view of a main part showing a configuration of a general cold cathode fluorescent tube. As shown in FIG. 6, both ends of a transparent glass tube 15 constituting the main body of the cold cathode fluorescent tube are sealed. A phosphor 16 is applied to the inner wall surface of the glass tube 15. Leads 11 pass through and are sealed at both ends of the sealed glass tube 15. An electrode 13 is provided at the tip of each lead in the glass tube 15.
Is connected. Each of the electrodes 13 is opposed to each other and arranged coaxially in the longitudinal direction of the glass tube 15. In the glass tube 15, for example, a mixed gas of argon and mercury is sealed. In addition, 14 is a mercury getter.

When a high voltage is applied between the two electrodes 13, cations and the like collide with the cathode electrode 13, whereby electrons are emitted from the cathode electrode 13 and discharge is started. Due to this discharge, a part of the gas sealed in the glass tube 15 is separated into electrons and cations. When the separated electrons and cations collide with the phosphor 16, the phosphor 16 is excited and emits light. Each of the electrodes 13 functions as a glow discharge electrode and an arc discharge electrode. A strong discharge can be stably obtained by a synergistic effect of the two, so that ultra-high-luminance light emission can be obtained.

Next, a conventional method for sealing the end of the cold cathode fluorescent tube shown in FIG. 6 will be described. FIG. 7 is a cross-sectional view showing a main step in sealing the end of the cold cathode fluorescent tube. First, the electrode 13 is caulked and fixed to one end of the lead 11 to which the glass beads 12 are fixed. Thus, the electrode assembly 10a shown in FIG. 7A is formed. next,
The electrode assembly 10a is inserted from the open end of the glass tube 15. Then, as shown in FIG. 7B, the electrode assembly 10
The periphery of the glass beads 12 of a is heated by the burner 105 from outside the glass tube 15. At this time, the glass tube 15
Heating is performed by the burner 105 while flowing a nitrogen gas therein. Thus, the glass tube 15 and the glass beads 12
Are melted, and the end of the glass tube 15 is sealed.

[0006]

FIG. 8 is an enlarged sectional view showing a part of the electrode assembly 10a shown in FIG. 7 (a). As shown in FIG. 8, the conductive portion 111 of the lead 11
Is made of an Fe—Ni alloy material having a surface plated with copper (Cu). A copper oxide film 1 made of Cu ₂ O (copper (I) oxide) is formed on the copper surface of the conductive portion 111.
The oxide film 112 is coated with a glass film 113.

Here, the function of the copper oxide film 112 and the glass film 113 of the lead 11 will be described. It is difficult to bond glass directly to metal. Therefore, the surface of copper, which is a metal, is covered with an oxide film 112 made of Cu ₂ O, and the glass beads 12 are bonded to the leads 11. However, Cu
₂ O is easily changed to CuO (copper oxide (II)) when exposed to air. This CuO has a very low hiding power. Therefore,
In order to isolate Cu ₂ O from the air, Cu ₂ O is coated with a glass film.

As described above, conventionally, when sealing the end of the glass tube 15, the glass tube 15 and the glass beads 12 are melted by heating with the burner 105. However, when the burner 105 is used, the glass bead 12 and the oxide film 112 made of Cu ₂ O are heated to 1000 ° C. or higher. When heated at an unnecessarily high temperature, the thickness of the oxide film 112 becomes extremely thin due to baking, and there is a risk that the glass beads 12 come into direct contact with the copper base surface. That is, since the glass is in direct contact with the metal, the sealing force between the glass tube 15 and the lead 11 is reduced. Thus, the airtightness in the glass tube 15 of the cold cathode fluorescent tube shown in FIG. 6 is reduced, which causes a leak and shortens the life of the cold cathode fluorescent tube.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such problems, and an object of the present invention is to provide a method of manufacturing an electron tube capable of manufacturing an electron tube having a long service life and hardly causing leakage. .

[0010]

In order to achieve the above object, the present invention provides an electrode assembly in which an electrode is connected to one end of a lead and a glass member smaller than the inside diameter of a glass tube is attached on the way. Prepare and exhaust the gas inside the glass tube with the electrode assembly inserted from one end of the glass tube from the electrode side, and heat the surroundings of the glass member of the electrode assembly from outside the glass tube with an electric heater Then, the glass tube and the glass member are melted to seal one end of the glass tube, and then, from the other end of the glass tube, an electrode assembly having substantially the same configuration as the above-described electrode assembly is placed on the electrode side. The gas in the glass tube is evacuated in a state where the glass tube is inserted from above, and the periphery of the glass member of the electrode assembly is heated with a heater from the outside of the glass tube to melt the glass tube and the glass member, and the other end of the glass tube is heated Seal.

If an electric heater is used, the heater can be heated at a lower temperature than a conventionally used burner. Therefore, even if the leads are covered with the oxide film, excessive diffusion of the oxide film layer due to burning can be prevented by heating with the heater. Therefore, when sealing the end of the glass tube, the glass material can be bonded to the lead via the oxide film.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram of a first embodiment of an electron tube manufacturing apparatus according to the present invention. The apparatus for manufacturing an electron tube shown in FIG.
It comprises a heater heating device 5a and a high-frequency heating device 6.

The sealing means 4 seals one end of the glass tube 15a of the electron tube when both ends are open. This sealing means 4 is provided at the end of the glass tube 15a.
Can be removed. The sealing means has a cap shape and a plug shape, and for example, a rubber one is used. The vacuum device 1 exhausts gas from the glass tube 15a having an open end. The vacuum apparatus 1 has a plurality of suction ports 1a, and can simultaneously exhaust a plurality of glass tubes 15a each having an opening end attached to each suction port 1a. Further, the vacuum apparatus 1 includes a unit for supplying an inert gas such as argon into the glass tube 15a. The vacuum device 1 and the sealing means 4 constitute an exhaust means.

The heater heating device 5a is an electric heater and has an electric heating coil. Heater heating device 5a
Can easily be heated at a desired temperature by controlling the power supplied to the electric heating coil. The heater heating device 5a is arranged outside the glass tube 15a.
The electric heating coil of the heater heating device 5a is arranged close to a glass tube 15a around glass beads of an electrode assembly described later.

FIG. 2 is a perspective view showing the arrangement of the electric heating coils of the heater heating device 5a. FIG. 2 (a) shows a case where the heater heating device 5a has four electric heating coils.
(B) shows a case where the heater heating device 5a has one electric heating coil.

As shown in FIG. 2A, when the heater heating device 5a has four electric heating coils 51, the electric heating coils 51 are arranged at equal intervals around the glass tube 15a. That is, each electric heating coil 51 is connected to the glass tube 1.
It is arranged every 90 ° around 5a. This makes it possible to uniformly heat the glass tube 15a and the glass beads of the electrode assembly. In this case, the number of the electric heating coils 51 included in the heater heating device 5a is not limited to four. Further, in order to heat the glass tube 15a and the like more evenly, each electric heating coil 51 may rotate around the glass tube 15a. Also, as shown in FIG.
When the heater heating device 5a includes one electric heating coil 52, the electric heating coil 52 is spirally arranged around the glass tube 15a.

The high-frequency heating device 6 is for high-frequency heating a mercury getter of an electrode assembly described later. The high-frequency heating device 6 is disposed outside the glass tube 15a, and the glass tube 1 around the mercury getter of the electrode assembly.
It is arranged close to 5a.

Next, a method of manufacturing a cold cathode fluorescent tube using the electron tube manufacturing apparatus shown in FIG. 1 will be described. FIG. 3 is a cross-sectional view showing main steps for manufacturing a cold cathode fluorescent tube. FIG. 4 is a cross-sectional view showing the main process subsequent to FIG. In FIGS. 3 and 4, the same or corresponding parts as those in FIGS. 6 and 7 are denoted by the same reference numerals.

First, the electrode assemblies 10a and 10b as shown in FIG. As described above, the lead 11 has a conductive portion 111 formed of an Fe—Ni alloy material with a copper plating on the surface, and a copper oxide film made of Cu ₂ O formed on the copper surface of the conductive portion 111. 112 and a glass film 113 which coats the oxide film 112. Both ends of the lead 11 are not covered with the oxide film 112 and the glass film 113.
The glass beads 12 are spherical glass members smaller than the inner diameter of the glass tube 15. Reed 11 and crow beads 12
Are connected via an appropriate oxide film 112.

The electrode 13 is formed by applying nickel plating to the surface of an iron plate. Two electrodes 13 are caulked and fixed to one end of the lead 11 to which the glass beads 12 are fixed, so as to face each other to form electrode assemblies 10a and 10b. However, on the glass tube 15 side of the electrode 13 of the electrode assembly 10b, a mercury getter 14 is formed. The mercury getter 14 is made of a Ti ₃ Hg alloy material. No mercury getter 14 is formed on the electrode 13 of the electrode assembly 10a.

The vacuum apparatus 1 shown in FIG. 1 has an electrode assembly support 2a and a glass tube support 3 in a suction port 1a. An electrode assembly 10a is attached to the electrode assembly support 2a.
Lead 11 is inserted. Further, the fluorescent material 16 is applied to the inner surface up to the glass tube supporting portion 3 of the suction port 1a, and one end of the glass tube 15 having both ends opened is inserted.

The positional relationship between the electrode assembly supporting portion 2a and the glass tube supporting portion 3 is determined by the lead 11 of the electrode assembly 10a.
Are arranged on the tube axis of the glass tube 15, and the glass beads 12 of the electrode assembly 10 a are arranged on a portion of the glass tube 15 where the phosphor 16 is not applied.
Is set. Further, the other end of the glass tube 15 is sealed by the sealing means 4. This state is shown in FIG.

Next, the gas in the glass tube 15 is evacuated by the vacuum device 1 from one end of the glass tube 15 while the electrode assembly 10a is inserted from the electrode 13 side. Reduce the pressure. For example, the glass tube 1
When the thickness of the glass of No. 5 is 0.45 to 0.6 mm, the pressure in the glass tube 15 is set to about 10 ⁻³ to 10 ⁻⁴ Torr. In this state, the outside of the glass tube 15 is heated around the glass beads 12 of the electrode assembly 10 a by the heater heating device 5.
The heater is heated in a. When the heated part of the glass tube 15 starts to melt, this part starts to indent due to the pressure difference between the inside and outside of the glass tube 15. Continue heating,
The glass tube 15 and the glass beads 12 are melted and sealed. This state is shown in FIG.

After the pressure in the glass tube 15 is reduced, an inert gas such as argon may be flowed into the glass tube 15 from the vacuum device 1 and then heated by the heater 5a. When the glass tube 15 and the glass beads 12 are heated and melted, the inside of the glass tube 15 is set to an inert atmosphere, so that oxidation of the electrode 13 can be prevented.

Next, after the glass tube 15 has cooled, an unnecessary portion at one end is cut off and removed.
Thus, a glass tube 15 having one end sealed as shown in FIG. 3D is obtained.

Subsequently, the other end of the glass tube 15 is sealed. First, the lead 11 of the electrode assembly 10b is inserted into the electrode assembly support 2a. Further, the sealing means 4 is removed from the other end of the glass tube 15, and the other end of the glass tube 15 is inserted into the glass tube supporting portion 3 of the suction port 1 a of the vacuum device 1. This state is shown in FIG.

Next, the gas in the glass tube 15 is exhausted from the other end of the glass tube 15 by the vacuum device 1 with the electrode assembly 10b inserted from the electrode 13 side. Subsequently, argon is poured into the glass tube 15 from the vacuum device 1 so that the pressure inside the glass tube 15 is set to about 20 to 100 Torr. In this state, the area around the glass beads 12 of the electrode assembly 10b is heated by the heater 5a from outside the glass tube 15. Then, the glass tube 15 and the glass beads 12 are melted and sealed. Next, an unnecessary portion at the other end of the glass tube 15 is cut off and removed. The glass tube 1 sealed at both ends in this manner.
5 is obtained.

Next, as shown in FIG. 4B, the mercury getter 14 sealed in the glass tube 15 is
Is heated by a high-frequency heating device 6 from the outside to evaporate mercury (Hg) from the mercury getter 14. As a result, a mixed gas of argon and mercury is sealed in the glass tube 15.

By the way, in the step of melting and sealing each end of the glass tube 15, the heater is heated so that the temperature of the glass beads 12 of each of the electrode assemblies 10a and 10b becomes 600 ° C. to 800 ° C. At such a temperature, it is possible to prevent the thickness of the oxide film 112 from becoming too thin by baking, so that when the end of the glass tube 15 is sealed, the glass material is led through the oxide film 112. 11 can be adhered. Thereby, the sealing force between the glass tube 15 and the lead 11 can be increased, so that the airtightness inside the cold cathode fluorescent tube can be improved.

[Second Embodiment] FIG. 5 is a sectional view showing a main part of a second embodiment of the apparatus for manufacturing an electron tube according to the present invention. In the electron tube manufacturing apparatus shown in FIG.
The electrode assembly support 2a is provided in the suction port 1a of the vacuum device 1. In the electron tube manufacturing apparatus shown in FIG.
Further, the sealing means 4 is also provided with an electrode assembly support 2b. The electrode assembly support 2b is fixed to the center of the sealing means 4. When the lead 11 of the electrode assembly 10a is inserted into the electrode assembly support 2b, the lead 11 of the electrode assembly 10a is It is arranged on the axis. In addition,
At this time, the glass beads 12 of the electrode assembly 10a are arranged in a portion of the glass tube 15 where the phosphor 16 is not applied.

The apparatus for manufacturing an electron tube shown in FIG.
It has two heater heating devices 5a and 5b. The heater heating device 5b has the same configuration as the heater heating device 5a of the electron tube manufacturing apparatus shown in FIG. The heaters 5a and 5b are disposed on both ends of the glass tube 15, respectively. Other configurations of the electron tube manufacturing apparatus shown in FIG. 5 are the same as those of the electron tube manufacturing apparatus shown in FIG.

Next, a method for manufacturing a cold cathode fluorescent tube using the electron tube manufacturing apparatus shown in FIG. 5 will be described. First, the electrode assemblies 10a and 10b shown in FIG. Next, the lead 11 of the electrode assembly 10b is inserted into the electrode assembly support portion 2a provided at the suction port 1a of the vacuum device 1, and the glass whose both ends are opened up to the glass tube support portion 3 of the suction port 1a. Insert one end of tube 15. Further, the electrode assembly supporting portion 2b provided in the sealing means 4 includes
The lead 11 of the electrode assembly 10a is inserted, and the other end of the glass tube 15 is sealed by the sealing means 4.

Next, while the electrode assemblies 10a and 10b are inserted from both ends of the glass tube 15 from the electrode 13 side, the gas in the glass tube 15 is exhausted by the vacuum device 1, Reduce the pressure. For example, glass tube 1
When the thickness of the glass of No. 5 is 0.45 to 0.6 mm, the pressure in the glass tube 15 is set to about 10 ⁻³ to 10 ⁻⁴ Torr. In this state, the outside of the glass tube 15 is heated around the glass beads 12 of the electrode assembly 10 a by the heater heating device 5.
The heater is heated in b. Then, the glass tube 15 and the glass beads 12 of the electrode assembly 10a are melted and sealed. Note that, at this time, the inside of the glass tube 15 may be set to an inert atmosphere, and then heating may be performed by the heater heating device 5b.

Next, the gas in the glass tube 15 is evacuated by the vacuum device 1, and then argon is flowed into the glass tube 15 from the vacuum device 1 to reduce the pressure in the glass tube 15 to 20 to 1.
Set to about 00 Torr. In this state, the area around the glass beads 12 of the electrode assembly 10b is heated by the heater 5a from outside the glass tube 15. Then, the glass tube 15 and the glass beads 12 of the electrode assembly 10b are melted and sealed. Next, unnecessary portions at both ends of the glass tube 15 are cut off and removed. Thus, a glass tube 15 having both ends sealed is obtained. The following steps are the same as the case of manufacturing using the electron tube manufacturing apparatus shown in FIG.

When the apparatus for manufacturing an electron tube shown in FIG. 1 is used, a step of replacing the glass tube 15 with the suction port 1a of the vacuum device 1 after sealing one end of the glass tube 15 is required. However, if the electron tube manufacturing apparatus shown in FIG. 5 is used, this step can be omitted. That is,
Since the cold cathode fluorescent tube can be manufactured in a small number of steps, the manufacturing cost of the cold cathode fluorescent tube can be reduced. In the first and second embodiments, a method for manufacturing a cold cathode fluorescent tube using the electron tube manufacturing apparatus shown in FIGS. 1 and 5 has been described. However, the apparatus for manufacturing an electron tube shown in FIGS. 1 and 5 is not limited to a cold cathode fluorescent tube, and is used for manufacturing an electron tube in which electrodes are hermetically sealed with a glass tube, for example, a vacuum tube and a discharge tube other than the cold cathode fluorescent tube. Can also be used.

[0036]

As described above, according to the present invention, the glass tube is evacuated with the electrode assembly inserted from one end of the glass tube, and heated by an electric heater so that one side of the glass tube is heated. Then, the glass tube is evacuated with the electrode assembly inserted from the other end of the glass tube, and the other end of the glass tube is sealed by heating with an electric heater. To wear. Thereby, even when the lead is covered with the oxide film, it is possible to prevent the thickness of the oxide film of the lead from becoming too thin when sealing the end of the glass tube. For this reason, since the sealing force at the end of the glass tube can be increased, it is possible to manufacture an electron tube that has a long life and is less likely to leak.

According to the second aspect of the present invention, the glass tube is evacuated while the electrode assemblies are inserted from both ends of the glass tube, and both ends of the glass tube are sealed by heating with an electric heater. . Thereby, since the electron tube can be manufactured in a small number of steps, the manufacturing cost of the electron tube can be reduced. In the invention according to the fourth aspect, when sealing the end of the glass tube, the glass member of the electrode assembly is heated so that the temperature of the glass member is 600 ° C. to 800 ° C. Thus, even if the leads are covered with the oxide film, it is possible to prevent the thickness of the oxide film from becoming too thin, so that it is possible to manufacture an electron tube having a long life and less occurrence of leakage.

According to the fifth aspect of the present invention, the glass tube is evacuated and then an inert gas is poured into the glass tube. When the glass tube and the glass member are heated and melted, the inside of the glass tube is set to an inert atmosphere, thereby preventing oxidation of the electrode. When sealing both ends of the glass tube, an inert gas can be sealed in the glass tube.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of an electron tube manufacturing apparatus according to the present invention.

FIG. 2 is a perspective view showing an arrangement of an electric heating coil of the heater heating device.

FIG. 3 is a cross-sectional view showing main steps for manufacturing a cold cathode fluorescent tube.

FIG. 4 is a cross-sectional view showing a main step following FIG. 3;

FIG. 5 is a sectional view of a main part showing a configuration of a second embodiment of an electron tube manufacturing apparatus according to the present invention.

FIG. 6 is a sectional view of a main part showing a configuration of a general cold cathode fluorescent tube.

FIG. 7 is a cross-sectional view showing main steps of a conventional sealing method of an end of a cold cathode fluorescent tube.

FIG. 8 is an enlarged sectional view showing a part of the electrode assembly.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vacuum apparatus, 1a ... Suction port, 2a, 2b ... Electrode assembly support part, 3 ... Glass tube support part, 4 ... Sealing means, 5a, 5
b: heater heating device, 6: high frequency heating device, 10a, 1
0b: electrode assembly, 11: lead, 12: glass bead, 13: electrode, 14: mercury getter, 15, 15a ...
Glass tube, 16: phosphor, 51, 52: electric heating coil, 1
11: conductive part, 112: oxide film, 113: glass film.

Continuation of the front page (72) Inventor Sato Winter 1-33-136 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Co., Ltd. Inside (72) Inventor Tsuyoshi Maeboshi 3-1-1-3, Noritakeshinmachi, Nishi-ku, Nagoya-shi, Aichi Prefecture Noritake Co., Ltd. F-term (reference) 5C012 JJ09

Claims (7)

[Claims] 1. Production of an electron tube comprising: a glass tube; leads sealed at both ends of the glass tube; and electrodes respectively connected to tips of the respective leads arranged in the glass tube. In the method, there is provided an electrode assembly in which the electrode is connected to one end of the lead, and a glass member smaller than the inner diameter of the glass tube is attached in the middle, and the electrode assembly is provided from one end of the glass tube. The gas inside the glass tube is exhausted while being inserted from the electrode side, and the periphery of the glass member of the electrode assembly is heated from outside the glass tube with an electric heater to separate the glass tube and the glass member. The glass tube was melted and sealed at one end, and then an electrode assembly having substantially the same configuration as the above-described electrode assembly was inserted from the other end of the glass tube from the electrode side. The gas in the glass tube is exhausted in a state, and the periphery of the glass member of the electrode assembly is heated by the heater from the outside of the glass tube to melt the glass tube and the glass member, and the other of the glass tubes A method of manufacturing an electron tube, comprising sealing an end of the electron tube. 2. Manufacture of an electron tube comprising: a glass tube; leads sealed at both ends of the glass tube; and electrodes respectively connected to tips of the respective leads arranged in the glass tube. In the method, an electrode assembly in which the electrode is connected to one end of the lead and a glass member smaller than the inner diameter of the glass tube is attached on the way, and an electrode assembly having substantially the same configuration as the electrode assembly are provided. The gas in the glass tube is exhausted in a state where the respective electrode assemblies are inserted from both ends of the glass tube from the electrode side, and the periphery of each glass member of each of the electrode assemblies is electrically supplied from outside the glass tube. A method of manufacturing an electron tube, comprising heating the glass tube and each of the glass members by heating with a heater of a type, and sealing both ends of the glass tube. 3. The method of manufacturing an electron tube according to claim 1, wherein the lead has an oxide film formed on a surface of a portion where the glass member is attached. 4. The temperature of each of the glass members of each of the electrode assemblies according to claim 1 or 2,
A method for producing an electron tube, wherein the method is heated to 00 ° C. 5. The method for manufacturing an electron tube according to claim 1, wherein the gas in the glass tube is exhausted, and then an inert gas is poured into the glass tube. 6. Production of an electron tube comprising: a glass tube; leads sealed at both ends of the glass tube; and electrodes respectively connected to tips of the respective leads arranged in the glass tube. In the apparatus, exhaust means for exhausting gas inside the glass tube, in which an electrode assembly in which the electrode is connected to one end of the lead and a glass member smaller than the inner diameter of the glass tube is attached in the middle is disposed. And heating the periphery of the glass member of the electrode assembly disposed in the glass tube from outside the glass tube to melt the glass tube and the glass member and seal an end of the glass tube. An apparatus for manufacturing an electron tube, comprising: a heater of a type. 7. The electron tube manufacturing apparatus according to claim 6, wherein the exhaust unit includes a sealing unit that seals one end when both ends of the glass tube are open.