Method of making a quartz crystal oscillator

• US 4,293,986 A
• Filed: 12/05/1978
• Issued: 10/13/1981
• Est. Priority Date: 12/05/1977
• Status: Expired due to Term

• Current Assignee: Matsushima Kogyo Kabushiki Kaisha
• Original Assignee: Matsushima Kogyo Kabushiki Kaisha
• Inventors: Kobayashi, Masatoshi, Fujii, Hiroyuki, Hara, Yukio, Shimakawa, George, Kabushiki Kaisha Seikosha
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US05/966,688
• Time in Patent Office: 1,043 Days
• Field of Search: 29/25.35, 310/344, 310/370, 228/121, 228/198
• US Class Current: 29/25.35
• CPC Class Codes: G04F 5/063 Constructional details
• CPC Class Codes: H03H 3/02 for the manufacture of piezoelectric or electrostrictive resonators or networks H03H3/08 takes precedence
• CPC Class Codes: H03H 9/0595 the holder support and resonator being formed in one body
• CPC Class Codes: H03H 9/1021 the BAW device being of the cantilever type
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A quartz crystal oscillator package comprising a quartz crystal vibrator leaf enclosed in an evacuated housing. The vibrator leaf frame is sandwiched and sealed between a pair of housing elements formed by etching at one time the periphery of each housing element and at another time etching a concave portion in each housing element. Opposed concave portions provide the internal volume wherein the vibrator leaf is sealed under vacuum. Using heat and vacuum, a metal film deposited on the sealing surfaces of the housing elements fuses with a binder material to form a eutectic alloy seal. A flat package having small size, high structural strength, an excellent hermetic seal, and high internal vacuum is produced by this method.

Claims

1. A method for manufacturing a quartz crystal oscillator package having a high internal vacuum, said package comprising a quartz crystal vibrator with a frame, a pair of housing elements having peripheral surfaces, said peripheral surfaces being shaped to register one to the other, a hermetic seal at the periphery of said oscillator package, comprising the steps of:

(a) coating said peripheral surfaces with a metal film;

(b) coating at least one of said metal films with a gas free material capable of forming an alloy with said metal film, said alloy forming coating being produced on said at least one said metal film at an ambient pressure less than 10^-2 torr, whereby gas is eliminated from said alloy forming coating during step (b);

(c) positioning said coated housing elements in an opposed position, said coatings being opposed one to the other, said crystal vibrator with a frame being enclosed within said opposed housing elements;

(d) drawing a high vacuum over the elements of said quartz crystal oscillator package and within said housing elements;

(e) applying heat under said high vacuum to fuse said alloy forming coating with said metal film to form an alloy whereby said housing elements are rigidly and hermetically joined together and said package has said high internal vacuum within said joined housing elements.

2. The method of claim 1, wherein said alloy is a eutectic alloy.

3. The method of claim 1, wherein said frame is coated with a metal film, said frame being sandwiched between said peripheral surfaces of said opposed housing elements, and said alloy forming coating element is interposed between said frame and said associated opposed housing elements.