A quartz-crystal unit comprises a container body having a recess, a quartz-crystal blank having a pair of excitation electrodes respectively disposed on one and the other principal surfaces, and a pair of extending electrodes respectively extended from the pair of excitation electrodes, and a cover for sealing an opening plane of the recess. The extending electrodes are led to both sides of one end of the crystal blank, and the one end is secured by a conductive adhesive to hold the crystal blank in the recess in parallel to the cover. The crystal unit satisfies 0<d/L<0.64, where L is the length from the one end to the other end opposing the one end in the crystal blank, and d is a gap between mutually opposing surfaces of the crystal blank and the cover.
An acceleration insensitive piezo-microresonator provides substantially reduced acceleration sensitivity with a plano--plano piezo-microresonator, upper gap and lower gap embedded in a rigid structural supporting member holding major surfaces of the piezo-microresonator firm and steady. The piezo-microresonator has neither electrodes on its surfaces nor contacts with any electrodes. Electrodes are doped regions incorporated into the support member. The upper and lower gaps are adjacent to the major surfaces of the piezo-microresonator, permitting it to vibrate freely. The support member surrounds and supports the plano--plano piezo-microresonator plate, upper gap and lower gap, maintaining a constant upper gap height and lower gap height. The electrodes provide a thickness-directed electrical field exciting the piezo-microresonator. A method of desensitizing a resonant frequency of a piezo-microresonator to acceleration stresses is also provided.
Manufacturing a piezoelectric vibration device, includes: forming a bonding electrode on a part of a piezoelectric substrate to which a cover makes contact; forming a part defining a through hole to the cover so that a profile of an edge of an opening of the through hole at a first surface of the cover is positioned inside an outer shape of the taking out electrode in a plan view when the cover and the piezoelectric substrate are overlapped; forming a first glass film on the first surface of the cover; forming a second glass film on the first surface of the cover; bonding the first glass film to the taking out electrode as well as the second glass film to the bonding electrode by generating an electric field; and cutting an electrical coupling between the taking out electrode and the bonding electrode after step (e).
