Nihon Dempa Kogyo Co., Ltd.

Tamotsu Kurosawa

Kozo Ono

Akio Chiba

Masahiro Yoshimatsu

Minoru Ishihara

A stacked crystal unit includes: a first crystal plate in which a vibration member links to an outer circumferential frame portion, and a pair of extending electrode extends to the frame portion from excitation electrodes; and a second and third crystal plates which have a concave portion in an area opposite to the vibration member and whose open end surfaces are joined by direct bonding to both principal surfaces of the frame portion in the first crystal plate. The extending electrodes are electrically extended to an outer surface of at least one of the second and third crystal plates via electrode through-holes provided in the frame portion. The electrode through-hole includes: a first electrode through-hole penetrating through the frame portion from the principal surface of the frame portion where the extending electrode extends; and a second electrode through-hole provided in the second or third crystal plate.

Crystal unit having stacked structure

A method of manufacturing a thin quartz crystal wafer from a quartz crystal block which is cut from a crystal body of synthetic quartz crystal and has a flat principal surface, comprises the steps of (a) converging a laser beam at a region in said quartz crystal block at a predetermined depth from the principal surface thereof to cause multiphoton phenomenon state, thereby breaking Si&#x2014;O&#x2014;Si bonds of quartz crystal in said region to form voids in said region, and (b) peeling said thin quartz crystal wafer from a body of said quartz crystal block along said voids. The above process is repeatedly performed on one quartz crystal block to peel off a plurality of thin quartz crystal wafers successively from the principal surface of the quartz crystal block. Each of the thin quartz crystal wafers is divided into individual quartz crystal blanks for making quartz crystal units.

Method of manufacturing thin quartz crystal wafer

A tuning fork type quartz crystal unit has a base and a pair of arms extending from respective ends of the base in a crystallographic Y direction of quartz crystal. Each of the arms comprises a first crystal member and a second crystal member which extend in the Y direction. The first crystal member and the second crystal member are joined to each other in a crystallographic YZ plane by a direct bonding such that the first crystal member and the second crystal member have respective crystallographic X directions oriented away from each other and extending parallel to each other. Each of the arms has excitation electrodes disposed respectively on a pair of exposed surfaces thereof which lie in the YZ plane. The direct bonding comprises, for example, a siloxane bond by which the first crystal member and the second crystal member are joined to each other.

Growing community of inventors

Saitama, Japan

Tamotsu Kurosawa