JPS6248888B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electronic components such as tantalum capacitors and methods of manufacturing the same, and in particular to housing electronic components with airtight terminals that have a metal ring on the outer circumferential surface and are insulated from terminals such as lead wires with glass. The present invention relates to an electronic component for sealing an open end of a metal case and a method for manufacturing the same.

In the case of electronic components that are conventionally housed in a metal case and sealed with airtight terminals as described above, if there is no problem in using solderable silver, copper, etc. as the metal case material, the metal case and airtight seal are used. The terminals were soldered and sealed. In the case of soldering, since the temperature was relatively low, there was almost no thermal effect on the hermetic terminal. However, due to the relationship with the electrolyte, such as electrolyte-filled wet tantalum capacitors, there are restrictions on the metal ring material for the metal case and airtight terminal, making it impossible or difficult to solder stainless steel, tantalum, titanium, etc.
In some cases, niobium or alloys thereof had to be used. Conventionally, arc welding (in an inert gas such as argon, if necessary) has generally been used to connect the metal ring of the airtight terminal to the metal case made of a material that is impossible or difficult to solder. However, when welding is performed using a heat source with low power linear density such as arc welding, the quality of the welded part changes and cracks occur, and the heat affects areas other than the welded area, causing damage to the glass of the airtight terminal, and damage to the metal. Problems such as separation of the ring and the glass or separation of the lead wire or terminal and the glass have occurred. In order to prevent these phenomena and to reduce the effect of heat during welding, attempts have been made to weld the airtight terminal or metal case with a heat sink of good thermal conductivity such as copper for the purpose of heat dissipation. ,
The heat effect cannot be avoided and the yield in the welding process alone is about 50%, which has the drawback of making the electronic parts expensive.

The present invention has been made in view of the above points, and is an electronic component having a structure in which a metal case housing an electronic component element is sealed with an airtight terminal, and the metal case and the airtight terminal are welded by laser welding. This is intended to eliminate heat effects on areas other than the welded area, improve yields, and provide low-cost electronic components. This will be explained below using examples. As shown in Fig. 1, a capacitor element 1 wound with tantalum foil has an outer diameter of 9.5 mm and a thickness of 0.35 mm.
It is housed in a metal case 2 made of stainless steel SUS304 with a diameter of 1.5 mm, and an electrolyte 3 is injected therein. The metal case 2
The airtight terminal 4 is inserted into the open end of the airtight terminal 4.
is the tantalum lead wire 5 connected to the capacitor element 1 in the center, and the thickness is
It consists of a metal ring 7 made of 0.35 mm stainless steel SUS304. The contact portion between the metal case 2 and the metal ring 7 is irradiated with a pulsed laser beam in an atmosphere of an inert gas such as Ar or N to melt the contact portion and seal the contact portion, but the laser beam irradiation conditions in this case are is as follows.

Pulse width: 7ms Voltage: 500v Focus deviation dimension: 7mm (Dimension B in Figure 2) Irradiation speed: 2 times/s Number of irradiations: 100 times For welding, as shown in Figure 2, capacitor element 1 and airtight terminal 4 are placed on rotating jig 8. Inlaid metal case 2
is placed, and the laser source 9 is determined by scanning the laser beam scanner of the welding machine so that the center of the laser beam is located on the joint surface between the metal case 2 and the airtight terminal 4. Thereafter, the focus of the laser beam is shifted in consideration of the thickness of the metal case 2 and the thickness of the metal ring 7 of the airtight terminal 4. Thereafter, the rotating jig 8 is rotated by irradiating a laser beam under the above-determined conditions set in advance, and the contact portions of the metal case 2 and the metal ring 7 are successively welded and sealed. In this embodiment, the rotating jig 8
Although the case has been described in which the laser source 9 is rotated, the laser source 9 may be moved along the contact portion between the metal case and the metal ring by scanning with a laser beam scanner. The results of an airtightness test on 50 capacitors in which the metal case 2 of the capacitor containing the element 1 wound with tantalum foil and the airtight terminal 4 were welded by a laser beam are shown below. The test conditions are He Leak.
Using a detector, a value of 5×10 ^-8 atm cc/s or less in terms of air was determined to be a good product, and there were no defects.

As described above, in an electronic component in which a metal case and a metal ring are welded by pulsed laser beam, the power line density of the laser beam during welding is high, so the thermal efficiency of the heat source is high and the amount of heat input is small. Therefore, since the heat affected area is small, it is possible to obtain welding with less occurrence of thermal deformation, thermal strain, etc. Furthermore, by using a pulsed laser beam, the deterioration of the welded area and the thermal effect on areas other than the welded area are so small that they can be completely ignored, and as mentioned in the conventional example, the yield during welding is about 50%. However, the electronic component according to the present invention was able to improve this to 100%. In the above embodiment, the metal case 2 and the metal ring 7 are made of SUS304, but the same effect can be obtained when they are made of one or more of tantalum, titanium, niobium, or stainless steel. However, it is obvious that the welding conditions will vary depending on the materials, thicknesses, etc. of the metal case and metal ring. It goes without saying that it can also be used for capacitors and electronic components other than tantalum capacitors.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of a capacitor according to the present invention, and FIG. 2 is a front sectional view showing an embodiment of an electronic component manufacturing apparatus according to the invention. 1...Capacitor element, 2...Metal case, 3
...Electrolyte, 4...Airtight terminal, 5...Tantalum lead wire, 6...Glass, 7...Metal ring, 8...Rotating jig.

Claims (1)

[Scope of Claims] 1. An electronic component in which an electronic component element is housed in a metal case and the open end of the metal case is sealed with an airtight terminal having a metal ring on the outer circumferential surface, wherein the metal case and the metal of the airtight terminal are sealed. An electronic component characterized by a ring welded using a laser beam. 2. The electronic component according to claim 1, wherein the metal case and the metal ring are made of one of stainless steel, tantalum, titanium, niobium, or an alloy thereof. 3. A method of manufacturing an electronic component, which comprises fitting an airtight terminal having a metal ring on the outer peripheral surface into the open end of a metal case housing an electronic component element, and irradiating and welding the contact portion between the metal case and the metal ring with a laser beam. 4. The method of manufacturing an electronic component according to claim 3, wherein the laser beam irradiation is performed in an inert gas atmosphere. 5. The method for manufacturing an electronic component according to claim 3 or 4, characterized in that the laser beam is intermittently irradiated. 6. The method for manufacturing an electronic component according to any one of claims 3 to 5, characterized in that the contact portion between the metal case and the metal ring or a laser beam scanner that irradiates the contact portion is rotated. .