Piezoelectric transducer having a crystal orientation selected from (xyl) + 31.7° (±1°) and (xyl) + 76.7° (±1°) or symmetrical equivalent

Abstract

A lithium niobate piezoelectric single crystal transducer having selected rotational orientations with respect to X, Y and Z rectangular coordinate axes. Compressional mode accelerometers having low or zero shear and torsion sensitivity are provided in which the crystal is oriented, in IRE notation, as (a) a (yxl) +38.6° cut or symmetrical equivalents thereof, such as (zxl) (b) a +60°/+51.4° cut. Shear mode accelerometers having low or zero compression sensitivity are provided in which the crystal is oriented, in IRE notation, as (a) (xyl) +31.7° cut, or symmetrical equivalents, and (b) an (xyl) +76.7° cut.

We claim: 
     
       1. In a piezoelectric device including at least one transducer element comprising a piezoelectric crystal, the improvement according to which said piezoelectric crystal is cut from a larger crystal of lithium niobate, said cut crystal having a crystal orientation selected from the following: .[.(yxl) + 38.6°(±1°), (zxtl) +60°(±1°)/+51.4° (±1°),.].   (xyl) +31.7°(±1°), (xyl) +76.7°(±1°), or a symmetrical equivalent thereof.  .[.2. The improvement according to claim 1 in which said cut crystal, has a (xyl) +38.6°(±1°)   
     
     
        orientation or a symmetrical equivalent thereof..]. 3. The improvement according to claim 1 in which said cut crystal, has an (xyl) +31.7°(±1°) orientation or a symmetrical equivalent 
     
     
        thereof. 4. The improvement according to claim 1 in which said cut crystal, has an (xyl) +76.7°(±1°) orientation or a symmetrical equivalent thereof.  .[.5. The invention according to claim 1 in which said cut crystal, has a (zxtl) +60°(±1°)/+51.4°(±1°) orientation or a symmetrical equivalent thereof..]. .[.6. In an accelerometer wherein a piezoelectric crystal is operatively associated in a compressional relationship with an inertial member, the improvement according to which said piezoelectric crystal is cut from a larger crystal of lithium niobate, said cut crystal, having a crystal orientation selected from the following: (yzl) +38.6°(±1°) and (zxtl) + 60°(±1°)/+51.4°(±1°),   or a symmetrical equivalent thereof..]. .[.7. The improvement according to claim 6 in which said cut crystal, has a (yzl) +38.6°(±1°) orientation or a symmetrical equivalent thereof..]. .[.8. The improvement according to claim 6 in which said cut crystal, has a (zxtl) + 60°(±1°)/+51.4°(±1°) orientation or a   
     
     
        symmetrical equivalent thereof..]. 9. In a piezoelectric accelerometer wherein a piezoelectric crystal is operatively associated in a shear relationship with an inertial member, the improvement according to which said piezoelectric crystal is cut from a larger crystal of lithium niobate, said cut crystal having a crystal orientation selected from the following: (xyl) +31.7°(±1°) and (xyl) +76.7°(±1°)   
     
     
        or a symmetrical equivalent thereof. 10. The improvement according to claim 9 in which said cut crystal, has an (xyl) +31.7°(±1°) orientation or a symmetrical equivalent 
     
     
        thereof. 11. The improvement according to claim 9 in which said cut crystal, has an (xyl) +76.7°(±1°) orientation or a 
     
     
        symmetrical equivalent thereof. 12. A single crystal plate of lithium niobate having a crystal orientation selected from the following: .[.(xyl) +38.6° (±1°), (zxtl) + 60°(±1°)/+ 51.4° (±1°),.]. (xyl) 31.7°(±1°) and (xyl) + 76.7°(±1°).  .[.13. The single crystal plate of claim 12 having a (xyl) + 38.6°(±1°) orientation..]. .[.14. The single crystal plate of claim 12 having a (zxtl) +60°(±1°)/+51.4°(±1°) orientation..]. 
     
     
            The single crystal plate of claim 12 having an (xyl) 
     
     
        +31.7°(±1°) orientation. 16. The single crystal plate of claim 12 having an (xyl) +76.7°(±1°) orientation.