JPH0521528U - Piezoelectric vibrator support bonding structure - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] By incorporating laser welding into the support bonding structure of the piezoelectric vibrator, metal-to-metal bonding without intervening foreign substances is performed, and bonding is ensured. [Structure] A pair of lead terminals 3 are hermetically and electrically insulated and sealed in a through hole of an oval hermetic base 1 via a hermetic glass 2, and a piezoelectric plate is inserted into an inner lead side of the lead terminal 3. In a hermetic terminal for a piezoelectric vibrator including a metal support 4 having a slit 10, the metal support 4 is brought into contact with the surface of the inner lead, a laser beam 7 is focused on the surface of the metal support 4 and melted, It is characterized in that the inner lead and the metal support 4 are welded to each other by metal to join them together.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a support joint structure for a piezoelectric vibrator.

[0002]

[Prior Art]

 A conventional support joint structure of a piezoelectric vibrator will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view showing a conventional piezoelectric vibrator, and FIG. 4 is a conventional front view before mounting a piezoelectric plate. Reference numeral 1 is an oval hermetic base having through holes near both ends in the longitudinal direction, and lead terminals 3 and 3 are hermetically and electrically insulated and sealed via hermetic glass 2 and 2 in each through hole. The inner leads 6, 6 of the lead terminals 3, 3 and the metal supports 4, 4 are attached by spot welding. As shown in FIG. 4, the welding direction is generally orthogonal to the center axis of the inner lead. During spot welding, the inner lead and the metal support are sandwiched from the above direction by a pair of electrode tips 8a and 8b, and current is applied while applying pressure. , Spot welding. The piezoelectric plate 5 is a circular AT-cut crystal plate, and the excitation electrode 11 (the back surface is not shown) is formed on the surface of the piezoelectric plate 5 by means such as vapor deposition. It is inserted between the slits 10 and 10 and is conductively fixed by a conductive bonding material (not shown).

[0003]

[Problems to be solved by the device]

 This had the following drawbacks. (A) Since the spot welding of the metal support and the inner lead applies pressure and current from the direction perpendicular to the center axis of the inner lead, the inner lead cannot be shorter than the length of the contact surface of the electrode tip. Therefore, when the support is joined and the piezoelectric plate is mounted to cover the cap to hermetically seal it, the cap becomes taller by the length of the inner lead, and therefore the piezoelectric vibrator cannot be downsized. Also, in the case of a cap of a size according to the standard, the piezoelectric plate has to be downsized by the length of the inner lead, and the area of the excitation electrode is accordingly reduced, which may lead to a CI value. (Crystal impedance value) becomes higher than the desired value, and the electrical characteristics of the piezoelectric vibrator deteriorate. (B) The shape of the welded part of the inner lead changes due to pressure and energization during spot welding. (C) The degree of shape change in (b) above is not constant due to the pressure applied during spot welding, the variation in energization, and the degree of electrode tip wear. The present invention has been made to eliminate these drawbacks.

[0004]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the piezoelectric vibrator of the present invention is constructed such that a pair of lead terminals are hermetically and insulatively sealed to a through hole of a hermetic base through glass, and the inner lead of the lead terminal is sealed. In a hermetic terminal for a piezoelectric vibrator, which is provided with a metal support having a slit for inserting a piezoelectric plate, the metal support is brought into contact with the surface of the inner lead, and the inner lead 4 and the metal support 5 are laser-welded to each other. Join together.

By injecting the above laser light while tilting upward from a direction perpendicular to the center axis of the inner lead, the metal support and the inner lead are joined with an inner lead length shorter than the above required inner lead length. can do.

[0006]

[Action]

 Since the inner lead and the metal support are joined by laser beam welding, the two are joined to each other without any intervening foreign substances, and the joining is ensured.

[0007]

【Example】

 Next, the present invention will be described with reference to the drawings. 1 is an exploded perspective view showing an embodiment of the present invention, and FIG. 2 is a front view showing an embodiment of the present invention when an inner lead length is short. In addition, the same type or the same portion as the drawing in the conventional example is denoted by the same reference numeral. Reference numeral 1 denotes an oval hermetic base having through-holes at both ends in the longitudinal direction, and lead terminals 3 and 3 are hermetically and insulatively sealed to each through-hole via hermetic glass 2 and 2. ing. A metal support 4 has a slit 10 into which the piezoelectric plate 5 can be inserted. The metal supports 4 and 4 are brought into contact with the surfaces of the inner leads 6 and 6 of the lead terminals 3 and 3, and the laser beam 7 is melted at the desired joining position 9 on the surfaces of the metal supports 4 and 4 and melted. 6 and 6 and metal supports 4 and 4 are welded to each other by metal to join them together. The piezoelectric plate 5 is a circular AT-cut crystal plate, and an excitation electrode 11 (the back surface is not shown) is formed on the surface thereof by means such as vapor deposition. The piezoelectric plate 5 is inserted between the slits 10 and 10 of the metal supports 4 and 4, and is conductively fixed by a conductive bonding material (not shown). These piezoelectric plates and the like are covered with a cap 12 made of a metal material and hermetically sealed.

Next, a laser welding method when the inner lead length is short will be described with reference to FIG. The laser beam 7 is tilted upward from the axis X-X in the direction perpendicular to the central axis Y-Y of the inner lead 6 and the focus of the laser beam is incident on the desired joining position 9 so that the inner beam required for FIG. The metal support 4 and the inner lead 6 can be joined with the inner lead length 6b shorter than the lead length 6a.

The output of the laser beam needs to be adjusted in consideration of the materials and thicknesses of the metal support and the inner lead so that they are not damaged more than necessary. For example, when 50 μm nickel silver is used as the metal support and laser beam welding is performed using the 0.6 mm kovar material as the lead terminal, a strong electromechanical joining can be performed with an output of 1 J.

[0010]

[Effect of the device]

 The following effects can be obtained by incorporating laser welding in the joint structure of the inner lead of the hermetic base and the metal support. (A) It is possible to shorten the inner lead length, so that it is possible to reduce the size of the piezoelectric vibrator when the external shape of the same piezoelectric plate is large, and when the external dimensions of the piezoelectric vibrator are the same, the large size of the piezoelectric plate is used. The size of the excitation electrode can be increased and the CI value (crystal impedance value) can be reduced, and the electrical characteristics of the piezoelectric vibrator can be improved. (B) Since the outer shape of the inner lead is not deformed at the time of joining, the residual strain on the metal support after joining is reduced. (C) Since the welding method is non-contact, there is no variation in the shape after welding due to the wear of the electrode tip, which is observed in the spot welding method.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the present invention.

FIG. 2 is a front view showing an embodiment of the present invention when the inner lead length is short.

FIG. 3 is a perspective view showing a conventional example.

FIG. 4 is a front view showing a conventional example.

[Explanation of symbols]

 1 Hermetic Base 2 Hermetic Glass 3 Lead Terminal 4 Metal Support 5 Piezoelectric Plate 6 Inner Leads 6a, 6b Inner Lead Length 7 Laser Light 8a, 8b Electrode Chip 9 Desired Joining Position 10 Slit 11 Excitation Electrode 12 Cap YY Inner Lead 6 Axis of X-X Y-Y

Claims (1)

[Scope of utility model registration request] 1. A pair of lead terminals are hermetically and insulatively sealed to a through hole of a hermetic base through glass,
In an airtight terminal for a piezoelectric vibrator, which comprises a metal support having a slit for inserting a piezoelectric plate on the inner lead of the lead terminal, the metal support is brought into contact with the surface of the inner lead, and the inner lead 4 and the metal support 5 are attached. Support bonding structure for piezoelectric vibrators, characterized by laser welding and metal-to-metal bonding.