JP2685886B2 - Electronic device stem - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stem for an electronic device having a standoff.

(Prior Art) When mounting an electronic device on a mounting board or the like, a standoff is formed on the outer surface of the case body so that the case of the electronic device does not directly contact the mounting board, and the standoff contacts the mounting board. There is a stem for an electronic device in which the case is separated from the mounting substrate.

5 and 6 show a conventional example of a standoff provided in a stem for an electronic device. In the figure, 10 is a case body and 12 is a standoff. The standoff 12 is formed by welding glass into a through hole 14 provided in the case body 10 and further projecting it in a hemispherical shape from the outer surface of the case body. As the glass forming the standoff 12, a glass having a smaller thermal expansion coefficient than the thermal expansion coefficient of the case body is used, and the glass is hermetically welded in the through hole 14 by the compressive force of the case body 10. There is. Normally, mild steel is used as the material of the case body 10, and soft glass is used as the material of the standoffs 12.

When forming the standoff, the glass hemispherical portion 16 is formed by welding glass so as to rise from the outer surface of the case body 10 in a hemispherical shape. When mounting an electronic device, attach the top of the glass hemisphere 16 formed on the stem to the mounting board as shown in the figure.
Abut on 18 and mount. By bringing the tops of the glass hemispheres 16 into contact with each other in this manner, a required gap is formed between the case body 10 of the stem and the mounting substrate 18.

In this way, standoff 12
If they are separated from each other, there is an advantage that the electrical insulation between the mounting substrate 18 and the electronic device is completed, and in the case where the electronic device generates heat, heat is not directly transferred to the mounting substrate.

(Problems to be Solved by the Invention) The conventional standoff is formed by welding glass into the through hole of the case body. However, as described above, the compression type is caused by the difference in the coefficient of thermal expansion between the case body and the glass. However, there is a problem that cracks occur in the standoffs 12 due to the compression stress. In particular, the corner portion a of the through hole 14 in which the shearing stress acts strongly on the glass when the case body 10 is stored.
Cracks are likely to occur. When a crack occurs, the glass hemisphere 16 may be chipped off and result in a defective product, or the airtightness of the through hole 14 may decrease, so it is necessary to take measures to prevent the standoff 12 from cracking. .

In FIG. 6, in order to prevent the occurrence of cracks at the corners of the through holes 14, the corners of the through holes 14 are chamfered to reduce the shearing stress applied to the glass at the corners. It is a thing. However, even if this chamfering is performed, it is extremely difficult to completely prevent the generation of cracks.

Further, since the glass flow-out state differs depending on the surface state of the outer surface of the case body, it is difficult to control the standoff size to be constant.

Therefore, the present invention has been made to solve the above problems, and the purpose thereof is to cause cracks in the standoffs due to the compression stress of glass welding, and as a result, the standoffs may be missing. The present invention seeks to provide a stem for electronic devices without a problem.

(Means for Solving the Problems) The present invention has the following configuration to achieve the above object.

That is, an electronic device having a standoff in which a glass having a smaller coefficient of thermal expansion than that of the metal of the case body is made to project further hemispherically from the outer surface of the case body and is welded to a hole provided in the metal case body for housing the electronic component. In the device stem, a projecting peripheral portion is formed around the hole on the outer surface of the case body,
The base portion of the hemispherical standoff is welded to the upper surface of the protruding portion. Further, a groove is provided around the hole on the outer surface of the case body to form a projecting peripheral portion between the groove and the hole, and the base of the hemispherical standoff is welded to the upper surface of the projecting peripheral portion. It is characterized by being formed. Also,
A step portion having a diameter larger than an inner diameter of the hole is formed at a peripheral portion of the hole on the outer surface of the case body, and a base side surface of the hemispherical standoff is welded to an inner wall surface of the step portion. And

(Function) By providing the protruding portion around the hole on the outer surface of the case body, the metal thickness of the corner portion of the hole where the compression stress acts most strongly becomes partially thin, and when the case body shrinks, Relieves the stress applied to. Also,
By providing a step on the periphery of the hole, the side surface of the base of the glass hemisphere is welded to the inside of the case body, reducing the stress concentration on the base of the glass hemisphere where compression stress acts most strongly. To do. In addition, by matching the outer diameter size of the outer wall surface of the projecting portion or the inner diameter size of the stepped portion with the outer diameter size of the glass hemisphere portion to be formed, it is possible to obtain a standoff having a constant size such as a height size. it can.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an embodiment of an electronic device stem having a standoff according to the present invention. In the figure, 10 is a case body and 12 is a standoff. Welding the through holes 14 with glass is similar to the conventional example. This embodiment is characterized in that a projecting peripheral portion 20 is provided around the through hole 14 on the outer surface of the case body 10. That is, the protruding portion 20 is formed as a ring-shaped protrusion on the outer surface of the case body 10 surrounding the through hole 14. Further, the outer peripheral diameter (ridge line portion) of the projecting peripheral portion 20 is formed so as to match the outer diameter size of the glass hemisphere portion 16 to be formed. Further, the corner portion of the inner wall surface of the projecting portion 20 is chamfered.

When the protruding portion 20 is provided on the outer surface of the case body 10 around the through hole 14 and the glass is welded as described above, the protruding portion is provided as shown in the figure.
20 The base of the glass hemisphere 16 is welded to the upper surface, and the stress at the corner of the through hole 14 where the compression stress has been the strongest in the past, is the protruding portion formed with a thin metal wall thickness.
Since it acts on the glass via 20, the shearing stress applied to the glass can be relaxed. That is, the projecting portion
By reducing the metal wall thickness of 20, it is possible to reduce the stress generated at the time of cooling after melting the glass and prevent the glass from cracking.

Since the angle between the upper surface of the protruding portion 20 for welding the glass and the outer wall surface of the protruding portion 20 is formed at an acute angle, the glass does not flow out to the outer wall surface of the protruding portion due to the surface tension of the molten glass. By forming the outer diameter size of the outer wall surface of the protruding portion 20 in the size of the glass hemisphere portion 16 to be formed, the shape of the glass is regulated by the protruding portion 20 to change the size of the glass hemisphere portion 16. There is also an effect that it can be formed uniformly.

FIG. 2 shows another embodiment of an electronic device stem having a standoff. In this embodiment, a groove 22 is provided around the through hole 14 on the outer surface of the case body. This groove 22
By forming the, the thin projecting peripheral portion 24 is formed on the outer surface of the case body around the through hole 14. The groove inner diameter size of the concave groove 22 is made to match the outer diameter size of the glass hemisphere portion 16 to be formed. Further, the corner portion of the inner wall surface of the projecting portion 24 is chamfered.

In the case of this embodiment, when the through hole 14 is glass-welded,
The outer diameter line of the base of the glass hemisphere 16 is projected on the upper surface of the protruding portion 24
It is welded almost in line with the ridgeline of the outer wall surface. The compression stress when welding glass is
Since it acts through the glass, the stress applied to the glass can be relaxed and the glass can be prevented from cracking.

FIG. 3 is an explanatory view showing a method of forming standoffs on the case body 10 shown in FIG. Reference numerals 30 and 31 denote carbon jigs for accommodating the case body 10. A glass tablet 32 is inserted into a through hole 14 provided in the case body 10 and heated to fuse the glass. The standoff forming portion of the carbon jig 30 is a void 33. The glass tablet 32 is made larger than the amount filling the through hole 14 at the time of melting so that the welded glass rises from the outer surface of the case body. The molten glass naturally has a hemispherical shape on the upper surface of the projecting portion, and a glass hemispherical portion 16 as shown in FIG. 2 is formed.

FIG. 4 shows still another embodiment. This embodiment is characterized in that a step portion 26 is provided on the peripheral portion of the through hole 14 on the outer surface of the case body. The diameter size of the inner wall surface of the stepped portion 26 is made substantially equal to the outer diameter size of the glass hemisphere portion 16. Also, the step 26
And the corner portion of the inner wall surface of the through hole 14 is chamfered.

When the step portion 26 is formed and the glass is welded to the through hole 14 as described above, the base side surface of the glass hemisphere portion 16 is welded to the inner wall surface of the step portion 26. As a result, the side surface of the base of the glass hemisphere 16 where the compression stress acts most strongly is welded to the inside of the case body, so that the compression stress acting on the base of the glass hemisphere 16 can be relaxed.

Even in the case of this embodiment, the glass does not flow out to the outer surface of the case body, and the outer diameter size of the glass hemisphere portion 16 is regulated by the diameter size of the inner wall surface of the stepped portion 26. The effect is that it can be kept constant.

The standoff 12 is formed by glass welding for the purpose of improving the reliability of the electronic device stem having the standoff, but in the product in which the lead is sealed with glass in the through hole provided in the case body, The lead glass sealing and the standoff glass welding can be performed at the same time, which is efficient in terms of work.

Further, in the case of the stem form of each of the above-mentioned embodiments, there is no difference in material from the current product, there is no significant change in the manufacturing process, and there is an advantage that no special equipment burden is imposed.

In this embodiment, the case body is formed with a through hole, and the standoff is glass-welded to the through hole. However, the hole for forming the standoff is not limited to the through hole. The present invention can be similarly applied to a hole which is not penetrated and which has a concave portion.

As described above, the present invention has been described variously with reference to the preferred embodiments. However, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. That is.

(Effect of the Invention) As described above, the electronic device stem of the present invention can relieve the shearing compression stress applied to the standoffs and prevent cracks from occurring in the standoffs. As a result, it is possible to prevent the occurrence of product defects such as chipping off of the standoff. Further, by providing the projecting peripheral portion and the stepped portion, it is possible to easily control the size of the standoff formed in the stem for the electronic device to a constant effect.

[Brief description of the drawings]

1 is a sectional view showing an embodiment of an electronic device stem according to the present invention, FIG. 2 is a sectional view showing another embodiment, FIG. 3 is an explanatory view showing a method of forming a standoff, and FIG. Is a cross-sectional view showing still another embodiment, and FIGS. 5 and 6 are cross-sectional views showing a conventional example of a standoff provided in a stem for an electronic device. 10 …… Case body, 12 …… Standoff, 14 …… Through hole,
16 …… Glass hemisphere, 18 …… Mounting board, 20 …… Surface,
22 …… Concave groove, 26 …… Step portion, 30, 31 …… Carbon jig,
32 …… Glass tablet.

Claims (3)

(57) [Claims] 1. A standoff in which glass having a coefficient of thermal expansion smaller than that of the metal of the case body is further protruded from the outer surface of the case body in a hemispherical shape and welded to a hole provided in a metal case body for housing electronic components. In the stem for an electronic device, the electronic device is characterized in that a protruding peripheral portion is formed around the hole on the outer surface of the case body, and the base of the hemispherical standoff is welded to the upper surface of the protruding peripheral portion. For stem. 2. A standoff in which glass having a smaller thermal expansion coefficient than the metal of the case body is further hemispherically projected from the outer surface of the case body and welded to a hole provided in a metal case body for housing electronic components. In the stem for an electronic device having a recess, a groove is provided around the hole on the outer surface of the case body, and a projecting peripheral portion is formed between the recess groove and the hole, and the base of the hemispherical standoff is the projecting peripheral portion. A stem for an electronic device, characterized by being welded to the upper surface of the part. 3. A standoff in which glass having a smaller thermal expansion coefficient than the metal of the case body is further hemispherically projected from the outer surface of the case body and is welded to a hole provided in a metal case body for housing electronic components. In a stem for an electronic device having a stepped portion having a diameter larger than an inner diameter of the hole is formed at a peripheral portion of the hole on the outer surface of the case body, and a base side surface of the hemispherical standoff is an inner wall surface of the stepped portion. An electronic device stem characterized by being welded to.