A vibrator suitable for use in a timepiece is provided which includes a crystal having a torsional vibrational mode, a pair of discrete electrode tracks deposited thereon, a continuous runner defining the discrete electrode tracks and a sole conductive support member for supporting the crystal and conductively mounting the crystal, as desired. The conductive support is connected to the crystal and the material of which the conductive support is fabricated is substantially identical with the material of the crystal. The crystal and support are preferably integrally connected and most preferably, they are integrally connected along a transverse, rigid channel which extends into a thickened, elongated body member. According to a second aspect of the invention, the crystal may be mounted on an oscillator terminal tag with opposed contacts fixedly connected thereto, each contact being connected to one of the respective discrete electrode tracks deposited on the crystal. The fixed connection between the contacts and conductive support may be a solder bond which secures the vibrator to the case. This mounting provides high Q value and shock-resistance.
CROSS REFERENCE TO RELATED APPLICATION
This application is a Continuation-In-Part of my copending application, Ser. No. 289,519, filed Sept. 15, 1972, now abandoned.
The micro-resonator comprises, cut from the same quartz crystal, a bar and a suspension frame means. The bar is cut in a substantially Z cut mode. The excitation electrodes are disposed on the sides of the bar. The length of the bar is substantially parallel to the Y axis. This produces a resonator which vibrates in a main mode of extension-compression, at from 0.5 MHz to 4 MHz.
A resonator has a parallelepipedal bar of a piezoelectric material designed to vibrate in an extension mode, and suspension means of said bar which form a single, integral part with the latter and which are only connected to one of its lateral faces. This arrangement makes it possible to reduce the number of parasitic vibration modes which could couple to the main mode as well as coupling between these modes, and hence variations as a function of the temperature in the characteristics of the resonator, notably in its quality factor.
Resonators adapted to be supported from a single support arm are made by a rocess wherein the resonator and its support arm are blanked in a single piece from a flat plate of piezoelectric material. The resonator electrodes are formed on the resonator and conductors formed on the support arm in a single metallization operation. If desired, the support arm may be left attached to the flat plate by a region of reduced cross section after the blanking step. The metallization step may include metallization of a portion of the flat plate to form a circuit over the conductor to the electrodes. The resonator may then be vibrated and tested while its support arm is still attached to the flat plate by applying an electrical potential to the metallized portion of the plate. After testing, the resonator support arm may be broken away from the flat plate at the region of reduced cross section. Several resonators may be made simultaneously by the process from a single flat plate of piezoelectric material.
A mounting is provided for a GT-cut, coupled mode piezoelectric resonator. The mount includes pedestals with recesses. Portions of the resonator are mounted in the recesses.
In a conventional quartz crystal resonator, a sacrificial quartz layer attached to the mounting posts and between the active, vibrating quartz layer and the package base reduces mechanical stresses on the active quartz layer caused by thermal expansion coefficient differences. The intermediate quartz layer is a sacrificial layer which acts to maintain the spacing of mounting posts.
