A resonant element includes: a fixed substrate having a main surface in orthogonal X- and Z-directions; a planar vibrating body fixed via support beams so as to be vibratable in an X-direction, the planar vibrating body having a weight portion which is isolated from the fixed substrate; an exciter for...http://www.google.com.hk/patents/US6430998?utm_source=gb-gplus-share專利 US6430998 - Resonant element
