FIG. 1 shows an example of a prior art vibrator support structure. In FIG. 1, a vibrator 9 is made by adhering piezoelectric elements 8a and 8b to two side surfaces 1a and 1b, respectively, that are adjacent but separated by a ridgeline of vibrator body 1 which vibrator body I has the overall shape of a rectangular column. Two support filaments 3 and 4, which are nearly rectangular U-shaped when seen from the front, are attached to ridgeline 2 which is opposite the aforesaid ridgeline separating the piezoelectric elements 8a and 8b. The feet of these support filaments 3 and 4 are attached on substrates 5c and 5d, respectively, which substrates 5c and 5d are positioned so as to be mutually separated on damper material 6 disposed on a support stand 7.
One end of each lead line 10a and 10b is connected to the piezoelectric elements 8a and 8b, respectively, while the other end of each lead line 10a, 10b is connected to terminals 11a and 11b, respectively. These terminals 11a and 11b, as well as ground terminal 11c connected to support filament 4, are connected to an electric circuit (not shown) via the respective lead wires 12a, 12b and 12c. When a drive a.c. voltage is applied from an electric circuit (not shown) via these lead wires 12a, 12b, 12c, 10a and 10b, and terminals 11a and 11b, to the piezoelectric elements 8a and 8b, vibrator 9 undergoes flexural vibration along the directions of the X-axis depicted in the drawing.
In a support structure of this sort, the main purpose of arranging damper material 6 over support stand 7 is to shield out external vibrations in order to prevent external leakage of the vibration of vibrator 9 and to remove the effects imparted to vibrator 9 by external vibration. The reason why substrates 5c and 5d are mutually separated on a single damper material 6 is to remove any restraint on the flexural vibration of vibrator 9 by freeing the back and forth displacement of the mountings of the support filaments 3 and 4 relative to vibrator 9.
However, this sort of vibrator support structure has problems in that the support posture of vibrator 9 may become rather unstable because substrates 5c and 5d are mutually separated on damper material 6. That is, when lead wires 12a, 12b and 12c are bent over during the packaging of the vibrator 9 arranged on support stand 7 together with the electric circuit connected to lead wires 12a, 12b and 12c inside a specified case, stresses such as tension and contraction occur in lead wires 12a, 12b and 12c. The subsequent transmittal of these stresses to substrate 5d causes deformations in damper material 6 that directly supports this substrate 5d, which damper material 6 comprises a soft material such as rubber or sponge. As a result, if the substrate 5d subsides somewhat after the stresses are removed, its left end side slants at an angle .THETA..sub.1, as shown for example by the side view in FIG. 2(a). The leg 4b of one support filament 4 attached to this substrate 5d compensates its posture of support for vibrator 9 by swaying somewhat toward the other support filament 3 from the vertical posture (as shown by the virtual line in the drawing) so that the stability of flexural vibration in vibrator 9 is lost. Also, when substrate 5d subsides at its left end side as shown in frontal view in FIG. 2(b), the single support filament 4 attached to substrate 5 distorts its posture relative to the vibrator axis thereby substantially decreasing the stability of flexural vibration.
This invention resulted from investigations undertaken to resolve the problems of such support structures. The object of this invention is to provide a vibrator support structure that does not impart an effect on the vibrator support posture arising from bending lead wires and, consequently, is capable of maintaining the constant stability of the flexural vibration of the vibrator.