Compression accelorometer utilizing a lithium niobate piezoelectric crystal

Claim 2

In a transducer of the compression type in which an electrical signal is developed across two flat parallel faces of a piezoelectric element in response to the relative motion of two mechanical members adapted to move relatively to each other in response to forces parallel to an axis perpendicular to such faces, said element being mounted between said two mechanical members, and in which means are provided for conducting such electrical signal to a utilization device responsive thereto, the improvement wherein said piezoelectric element comprises a lithium niobate crystal having its Z-axis at an angle of about -51.4* + or - 10* to an axis normal to said parallel faces.

Claim 3

A transducer as defined in claim 1 comprising an accelerometer wherein said element is of cylindrical configuration and in which one of said two members constitutes an inertial member supported by said element from the other of said two members and wherein said electrical signal is developed in response to the acceleration of an object that is secured to the other of said two members.

Claim 4

An accelerometer as defined in claim 2 wherein one of said members has a base provided with a base surface attachable to the surface of said accelerating object, said base surface being in a plane parallel to said flat parallel surfaces of said element.

Claim 5

An accelerometer as defined in claim 3 wherein communication is provided between said crystal and an oxygen containing atmosphere and providing a cover member cooperating with one of said two members for enclosing said crystal.

Claim 6

An accelerometer as defined in claim 2 comprising at least two annular piezoelectric elements mounted on a post secured to said base and having their sensitive axes anti-parallel with the outer surfaces thereof electrically connected together and having a common electrode between adjacent surfaces.

Claim 7

A transducer as defined in claim 1 in which said element has a central hole therein and a post extends through said element, said two members being composed of metal.

Claim 8

In a transducer of the compression type in which an electrical signal is developed across two flat parallel faces of a piezoelectric element in response to the relative motion of two mechanical members adapted to move relatively to each other in a direction perpendicular to such faces, which element is mounted between said two mechanical members, and in which means are provided for conducting such electrical signal to a utilization device responsive thereto, the improvement wherein said piezoelectric element comprises a lithium niobate crystal containing impurities, said crystal having a Z axis rotated theta * + or - 10* from an axis normal to said parallel faces, the angle theta being the counterclockwise angle through which the Z-axis is rotated about the X axis such that the d34 piezoelectric coefficient is equal to zero.

Claim 9

In a transducer of the compression type in which an electrical signal is developed across two flat parallel faces of a piezoelectric element in response to the relative motion of two mechanical members adapted to move relatively to each other in a direction perpendicular to such faces, which element is mounted between said two mechanical members, and in which means are provided for conducting such electrical signal to a utilization device responsive thereto, the improvement wherein said piezoelectric element comprises a lithium niobate crystal containing impurities, said crystal having a Z axis rotated theta * + or - 10* from an axis normal to said parallel faces, the angle theta being the counterclockwise angle through which the Z-axis is rotated about the X axis such that the d34 piezoelectric coefficient is equal to zero.