Patent ID: 6564639
Filing Date: 2003-05-20
Classification: G01C

Abstract:
An angular rate sensor comprising:a tuning fork vibrator having at least two tuning fork prongs and at least one tuning fork base, said tuning fork vibrator comprising a first vibrator having a first orientation of crystallographic axis and a second vibrator having a second orientation of crystallographic axis, said first vibrator and said second vibrator being directly bonded into one piece such that the first orientation of crystallographic axis is opposite to the second orientation of crystallographic axis thereby producing a piezoelectric phenomenon of reversed polarity with respect to each other in a first direction and a second direction; a first electrode disposed on a front surface of a first tuning fork prong; a second electrode disposed on a front surface of a second tuning fork prong; a third electrode disposed on a back surface of one of said first and said second tuning fork prongs; a fourth electrode disposed on a back surface of another of said first and said second tuning fork prongs; fifth through eighth electrodes disposed on two surfaces of said first tuning fork prong and two surfaces of said second tuning fork prong, respectively; and a driving power supply operable to supply driving signals, wherein said fifth through said eighth electrodes are sensor electrodes and are parallel to one another in a driving direction of said tuning fork vibrator, wherein said first vibrator comprises at least two prongs and at least one base connecting said at least two prongs, wherein said first vibrator comprises a first mono-quartz piezoelectric material, wherein said second vibrator comprises a second mono-quartz piezoelectric material in a shape generally similar to said first vibrator, wherein one of said first electrode and said third electrode is a first driving electrode, and one of said second electrode and said fourth electrode is a second driving electrode, wherein said driving power supply is operable to supply a first driving signal having a first phase to said one of said first electrode and said third electrode connected thereto, wherein said driving power supply is operable to supply a second driving signal having a second phase different from said first phase to said one of said second electrode and said fourth electrode connected thereto, wherein said fifth electrode is disposed on an exterior-side surface of one of said first tuning fork prong and said second tuning fork prong, wherein said eighth is disposed an other exterior-side surface of the other of said first tuning fork prong and said second tuning fork prong, wherein said sixth electrode is disposed on an interior-side surface of one of said first tuning fork prong and said second tuning fork prong, wherein said seventh electrode is disposed on an interior-side surface of the other of said first tuning fork prong and said second tuning fork prong, wherein said fifth electrode and said eighth electrode are commonly connected together, wherein said sixth electrode and seventh electrode are commonly connected together, and wherein said fifth through said eighth electrodes are arranged and connected to enable said angular rate sensor to obtain a sensor signal from points of the common connections.