JP2017091941A - Metal wire antioxidation manufacturing method with glass beads - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal wire antioxidation manufacturing method which does not require plating treatment or a large container for sealed space although a noble metal such as platinum may be required and cost may be extremely increased when performing the plating treatment as metal wire antioxidation measures, and a processing device may be enlarged and workability or the like may be reduced since a container for the sealed space may be required separately in processing using a non-oxidative atmosphere.SOLUTION: In the metal wire antioxidation manufacturing method with glass beads, a metallic lead wire comprises hollow glass beads. After the metallic lead wire is installed at a specified place inside of a glass tube in a hollow cylindrical shape, the metallic lead wire is heated by a gas burner, the glass beads are molten and a metal surface of the metallic lead wire is protected. Further, by heating the gas burner, the glass tube is molten, and the glass beads in a molten state and the glass tube are joined. Thereafter, the glass tube is molded into a desired shape by press or the like and a glass foundation is processed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a manufacturing process of an electronic device having a hermetically sealed structure that holds a sensor therein, and a metal used to transmit an electrical signal to the sensor or to output an electrical signal from the sensor. In a manufacturing process in which an element is passed through the hermetic sealing member and fixed to the hermetic sealing member, an oxide film is not generated on the surface of the metal element, thereby reducing the hermetic sealing performance of the electronic device. It relates to manufacturing technology to prevent.

The hermetic sealing member is glass, and the metal material that transmits an electrical signal is a UV sensor used for flame detection using a metal plate as a sensor as the electronic device having a hermetic sealing structure including a Kovar wire. . The UV sensor seals in the UV sensor a pair of discharge electrodes that generate a discharge upon receiving ultraviolet rays contained in a flame, and each lead wire of the pair of discharge electrodes (metal plates) is connected to one end of the glass tube. From the department. The UV sensor is used as a flame sensor for monitoring the combustion state in the boiler.

In the production of the glass tube, which is a constituent element of the UV sensor, a production process for melting a glass material by heating a gas burner and fixing a Kovar wire is conventionally known. FIG. 4 is a cross-sectional view illustrating the overall configuration of the UV sensor. In FIG. 4, 10 is a UV sensor, 11 is a cap portion of a glass tube, 15 and 16 are metal lead wires (actually Kovar wires) for electric signal transmission, and 12 is a joint with the Kovar wires 15 and 16. The glass bases 13 and 14 are metal electrodes (metal plates) having a disk shape or a square shape.

An AC or DC voltage is applied to the 15 and 16 Kovar wires for electric signal transmission.
FIG. 4 does not describe the voltage application device. The inside of the UV sensor 10 discharges air and is filled with a discharge gas that is also a sealing gas. When ultraviolet light transmitted from the 11 cap portion collides with the electrode 14, a discharge phenomenon occurs, and a current flows between the 15 and 16 Kovar lines. A detector (not shown) that detects that the current has flowed outputs to the outside that ultraviolet rays have been detected.

FIG. 5 is a development view of the UV sensor 10, and the components of the UV sensor 10 will be described. FIG. 6 is a diagram illustrating the configuration of the lead wires 15 and 16 and the glass base 12. FIG. 6A shows that the Kovar wires 15 and 16 penetrate the glass base 12 and are fixed to the glass base 12. FIG. 6B shows a state before the Kovar wires 15 and 16 are fixed to the glass base 12.

As a manufacturing process to be processed into the state of FIG. 6A, conventionally, with the gas burner or the like, the Kovar wires 15 and 16 and the glass base 12 are heated, and the glass base 12 is melted. A manufacturing process is used in which the Kovar wires 15 and 16 are brought into contact with the specified positions of the glass base 12 and then cooled and fixed.

In the manufacturing and manufacturing process for joining the Kovar wires 15 and 16 and the glass base 12, the Kovar wires 15 and 16 are heated by the gas burner, so that the surfaces of the Kovar wires 15 and 16 are oxidized and an oxide film is formed. It is formed. The oxide film is often porous.

When the oxide film is porous, the discharge gas sealed inside the UV sensor 10 leaks to the outside through the oxide film, and as a result, the airtightness may not be maintained. That is, if an oxide film is present, the location may cause a leak.

Japanese Patent Laid-Open No. 05-258909 discloses a technique for plating a noble metal on the lead wire of a glass-enclosed thermistor as a technique for preventing oxide film in a manufacturing process that penetrates and fixes a lead wire to a glass material used for hermetic sealing. Kaihei 08-078208 discloses a technique for preventing oxidation of the surface of a lead wire in a non-oxidizing atmosphere or an inert atmosphere in a glass-sealed thermistor element and its manufacturing method.

Japanese Patent Laid-Open No. 05-258909 JP 08-078208

As a countermeasure for preventing oxidation of metal wires, when plating is performed, a noble metal such as platinum is required, which is very expensive. In addition, since a container for a sealed space is required separately in processing using a non-oxidizing atmosphere, the processing apparatus becomes large and workability is reduced. There is a need for a metal wire oxidation-preventing manufacturing method that does not require the plating process or a large container for a sealed space.

The metal lead wire is provided with hollow glass beads, and after the metal lead wire is installed at a prescribed place inside the hollow cylindrical glass tube, the glass lead is melted by heating with a gas burner. The metal surface of the metal lead wire is protected. Further, by heating the gas burner, the glass tube is melted, and the molten glass beads and the glass tube are joined. Then, the metal wire oxidation prevention manufacturing method by the glass bead which shape | molds the said glass chip into a desired shape with a press etc., and processes a glass base.

Protects the surface of metal lead wires to reduce the possibility of oxide film generation, and eliminates the need for surface plating of the lead wires and the processing of the lead wires in an inert atmosphere. Can provide significant benefits.

Start of metal wire oxidation prevention manufacturing Manufacturing process during melting of glass beads Manufacturing process during bonding of glass beads and glass material Cross section of UV sensor Development view of UV sensor Illustration of the composition of the Kovar wire and glass base

Embodiment 1 of the present invention will be described in detail with reference to FIGS. 1 to 3 and FIG.
Embodiment 1 FIG.
As shown in FIG. 4, the hermetic sealing material of the UV sensor 10 used as a flame sensor is a glass material composed of a glass tube cap portion 11 and a glass base 12 through which Kovar wires 15 and 16 penetrate. It is.
The present invention uses one or a plurality of cylindrical glass beads for each Kovar wire in a manufacturing process in which a glass material is melted by heating a gas burner to join the glass base 12 and the Kovar wires 15 and 16. Features.

FIG. 1 is a diagram for explaining a starting state of metal wire oxidation prevention manufacturing. The Kovar wires 15 and 16 are passed through hollow cylindrical glass beads 17-0 and 18-0, and the glass beads are set at predetermined positions of the Kovar wire. In addition, the manufacturing apparatus which sets the said Kovar wire to the said glass bead is not described in FIG. One or more glass beads may be used. 12-0 is a hollow cylindrical glass tube that becomes the glass base 12 after processing. The Kovar wires 15 and 16 provided with the hollow cylindrical glass beads 17-0 and 18-0 are installed at predetermined locations inside the hollow cylindrical glass tube 12-0. A gas burner 19 is mounted on a mechanism (not shown) that moves back and forth in the direction of the glass tube. Reference numeral 20 denotes a gas burner flame of the gas burner 19. The glass beads 17-0 and 18-0 and the glass tube 12-0 are heated by directing the gas burner flame 20 toward the hollow cylindrical glass tube 12-0. As a manufacturing apparatus according to the present invention, a temperature sensor (not shown) that measures the temperature of both the hollow cylindrical glass beads 17-0 and 18-0 and the glass tube 12-0 or the glass tube 12-0. For example, there is a radiation thermometer, and there is a control device (not shown) for adjusting the heating power of the gas burner 19 based on the measured value of the temperature sensor. In addition, air and a fuel system to be supplied to the gas burner 19 are provided but are not shown in the figure.

FIG. 2 is a diagram illustrating a manufacturing process during melting of glass beads. The glass beads 17-1 and 18-1 are melted by the heating of the gas burner flame 20 and are attached to the surfaces of the Kovar wires 15 and 16. Although related to the volume of the glass material, the heat capacity of the hollow cylindrical glass tube 12-1 is set to a value smaller than the heat capacities of the glass beads 17-1 and 18-1. Therefore, in the state heated at the same high temperature by the gas burner flame 20, the glass beads 17-1 and 18-1 having a small heat capacity are melted in time earlier than the hollow cylindrical glass tube 12-1.

Since the melting temperature of the metal Kovar wire is 1450 ° C. and the glass melting point temperature is 705 ° C., the temperature at which the gas burner flame 20 heats the glass is lower than the melting temperature of the metal Kovar wire 1450 ° C. Control is performed by a control device (not shown) such that the melting point is higher than 705 ° C., for example, 800 ° C. By adopting this temperature condition, the glass beads 17-1 and 18-1 are dissolved and the Kovar wires 15, 16 are dissolved before the surfaces of the Kovar wires 15, 16 are oxidized to form a porous oxide film. It sticks to the surface of 16. Since the glass beads 17-1 and 18-1 dissolved in this manner prevent the formation of oxide films on the surfaces of the Kovar wires 15 and 16, the glass beads 17-1 and 18-1 and the Kovar. The junction interface between the lines 15 and 16 does not cause a leak.

FIG. 3 shows a manufacturing process in which a glass tube having a hollow cylindrical shape is melted by joining a melted glass bead and a Kovar wire and then a gas burner flame is continuously applied to bond the glass bead and the glass tube. It is a figure which shows a process. 12-2 is the glass tube of the said hollow cylindrical shape of the melted state.

After the glass beads 17-1 and 18-1 and the glass tube 12-2 are fused as shown in FIG. 3, the air and fuel supplied to the gas burner 19 are throttled to weaken the gas burner flame 20 and move the gas. The gas burner 19 is retracted from the glass tube 12-2 by a mechanism.

Then, a press machine (not shown) is moved toward the glass tube 12-2 in a high temperature state, and the glass tube 12-2 is shaped into a prescribed shape, specifically, the glass base 12 of the UV sensor 10. To process.

The air and fuel to the gas burner 19 are increased again to strengthen the gas burner flame 20 and gradually cool the glass base 12 so that the glass material does not rapidly cool.

By adopting the metal wire oxidation-preventing manufacturing method using the glass beads of the present invention, heating of the surface of the metal lead wire and generation of an oxide film due to contact with oxygen are prevented. Further, unlike the plating process on the surface of the lead wire used for preventing the oxidation of the lead wire, an expensive noble metal such as platinum is not required, so that the cost can be reduced.

In the manufacturing process in which the sealed space is filled with a non-oxidizing atmosphere and the lead wire is processed without generating an oxide film, the processing apparatus becomes expensive and large, and workability and the like are reduced. However, since the present invention does not require the use of such an expensive apparatus, it can be manufactured at low cost with little risk of deterioration in workability.

It is described that manufacturing process No. 1 in which glass beads are melted and bonded to Kovar wire and manufacturing process No. 2 in which the hollow cylindrical glass tube is heated and melted and bonded to glass beads are performed continuously. However, the manufacturing steps 1 and 2 may be performed in separate steps in time or space.

After the electrodes 13 and 14 are welded to the Kovar wires 15 and 16 of the glass base 12 manufactured by the metal wire oxidation prevention manufacturing method of the present invention, the glass base 12 and the glass tube cap part, respectively. 11 is heated and melted with a gas burner, and further tightly fused to form an airtight sealed structure. Thereafter, the UV sensor 10 is completed by filling the inside with a discharge gas (sealing gas). A manufacturing process in which a gap is provided in a part of the glass tube cap portion 11 or the glass base 12, the discharge gas is filled through the gap from the outside of the UV sensor 10, and then the gap is closed is a conventional manufacturing process. Can be realized with technology.

10 UV sensor
DESCRIPTION OF SYMBOLS 11 Cap part of glass tube 12 Glass foundation 12-0, 12-1 Glass tube 12-2 Glass tube of melted state 13 Anode electrode 14 Cathode electrode 15, 16 Kovar wire (lead wire)
17-0, 17-1 Glass beads 18-0, 18-1 Glass beads 19 Gas burner 20 Gas burner flame

Claims (5)

A manufacturing method of melting a glass material by heating and joining the glass lead and the glass material,
After the hollow cylindrical glass beads are penetrated through the metal lead wire and set in a predetermined position of the metal lead wire, the metal lead wire is placed at a predetermined place inside the hollow cylindrical glass tube. By using glass beads, the glass beam and the glass tube are heated and melted by a gas burner and bonded to the metal lead wire to produce a glass base for hermetic sealing. Metal wire oxidation prevention manufacturing method. In claim 1,
The method for producing metal wire oxidation-preventing by using glass beads, wherein the heat capacity of the hollow cylindrical glass tube is larger than the heat capacity of the glass beads. 2. The temperature sensor for measuring the temperature of both the hollow cylindrical glass tube and the glass bead or one of the surfaces, and the control for controlling the flame strength of the gas burner by a signal from the temperature sensor. A metal wire oxidation-preventing manufacturing method using glass beads, comprising an apparatus. In claim 3,
The temperature at which the hollow cylindrical glass tube and the glass beads are heated by the gas burner is higher than the melting temperature of the hollow cylindrical glass tube and the glass beads and lower than the melting temperature of the metal lead wire. A method for producing metal wire oxidation-preventing by glass beads, characterized by being at a specific temperature. In claim 1,
The method for producing metal wire oxidation-preventing by glass beads, wherein the glass beads before melting are one or a plurality of hollow cylindrical glasses.

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