Surface mount crystal oscillator

Abstract

A surface mount crystal oscillator has a package body having a recess and formed with a step on an inner wall of the recess, a flat base plate having a peripheral region secured to the step, a crystal blank secured to the flat base plate, an IC chip having an oscillation circuit, using the crystal blank, integrated therein, and secured to a bottom surface of the recess, and a cover for closing the recess. The crystal blank is disposed above the IC chip within the recess, and the IC chip and the crystal blank are hermetically sealed within the recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating the configuration of a conventional one-chamber type surface mount crystal oscillator;

FIG. 2 is a plan view illustrating a crystal blank;

FIG. 3 is a cross-sectional view illustrating the configuration of a conventional bonding type surface mount crystal oscillator;

FIG. 4A is a cross-sectional view illustrating a surface mount crystal oscillator according to one embodiment of the present invention;

FIG. 4B is a plan view illustrating a flat base plate;

FIG. 4C is a plan view of the flat base plate when a crystal blank is attached to the back side thereof; and

FIG. 5 is a cross-sectional view illustrating the configuration of a surface mount crystal oscillator according to another embodiment of the present invention.

Claims

1. A surface mount crystal oscillator comprising: a package body having a recess and formed with a step on an inner wall of the recess;a flat base plate having a peripheral region secured to the step;a crystal blank secured to said flat base plate;an IC chip having an oscillation circuit integrated therein, and secured to a bottom surface of the recess, said oscillation circuit using said crystal blank; anda cover for closing the recess,wherein said crystal blank is disposed above said IC chip within the recess, and said IC chip and said crystal blank are hermetically sealed within the recess.

2. The crystal oscillator according to claim 1, further comprising: a pair of excitation electrodes disposed respectively on both main surfaces of said crystal blank; anda pair of lead-out electrodes extended respectively from said excitation electrodes to both ends of one side of said crystal blank,wherein said crystal blank is secured to said flat base plate along a peripheral region thereof to which said lead-out electrodes are extended.

3. The crystal oscillator according to claim 2, further comprising a pair of holding terminals disposed on a surface of said flat base plate, wherein said crystal blank is held on said flat base plate by electrically and mechanically connecting both ends of the one side of said crystal blank to said holding terminals with a conductive adhesive.

4. The crystal oscillator according to claim 2, wherein: said flat base plate includes an opening formed through a central region thereof to expose one of said excitation electrodes, andsaid crystal blank is disposed between said flat base plate and said IC chip in the recess.