Angular velocity sensor
First Claim
1. An angular velocity sensor formed from crystal material having crystal axes, said crystal axes including an electrical axis, a mechanical axis, and an optical axis,said angular velocity sensor comprising four parallel oscillating arms and a first and second support member for commonly holding the four parallel oscillating arms at both ends of each of the four parallel oscillating arms, said angular velocity sensor configured such that a base of said annular velocity sensor extending along a width of said angular velocity sensor is positioned on said electrical axis, a direction along a length of said angular velocity sensor forms an angle θ
- with said mechanical axis and a direction along a depth of said angular velocity sensor forms the same angle θ
with said optical axis, two of said four oscillating arms defining a driving side tuning fork and the other two of said four oscillating arms defining a detecting side tuning fork, wherein each of the two oscillating arms of the detecting side tuning fork being cut in a middle portion of a respective oscillating arm such that each of said two oscillating arms of said detecting side tuning fork comprises a first and a second oscillating arm, said first oscillating arm of each of said two oscillating arms of said detecting side tuning fork extending from said first support member and said second oscillating arm of each of said two oscillating arms of said detecting side tuning fork extending from said second support member, each of said first and second oscillating arms of each of said two oscillating arms of said detecting side tuning fork being positioned either outside or inside of said two oscillating arms of said driving side tuning fork, said angular velocity sensor further comprising driving electrodes positioned on face and back surfaces or side surfaces of the driving side tuning fork and detecting electrodes positioned on face and back surfaces or side surfaces of the detecting side tuning fork such that applying an alternating-current power to the driving electrodes in either or both oscillating arms of the driving side tuning fork generates and maintains a width direction flexural oscillation in mutually reverse phases on the driving side tuning fork, wherein when an angular velocity vector rotating and acting on the entire angular velocity sensor is applied from outside, said angular velocity sensor detects an electric charge generated in the detecting electrodes by a thickness direction flexural oscillation in mutually reverse phases on the detecting side tuning fork induced from a driving force of a thickness direction component of Coriolis force acting in an oscillating portion in the width direction of the driving side tuning fork or detecting side tuning fork, thereby obtaining an electrical signal in proportion to an input angular velocity.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to an angular velocity sensor used in posture control of a moving element or navigation system, and is intended to realize higher sensitivity, lower offset, lower offset drift, lower translation acceleration sensitivity, and higher impact resistance in a small size and at low cost.
Being made of ceramic piezoelectric material or crystal material, the constitution comprises four parallel oscillating arms 12 to 15, or 112 to 115, and a support member 11, or 111 for supporting one end of the oscillating arms or both ends commonly, in which outer two oscillating arms 12, 15, or 112, 115 of a compound tuning fork 10, or 110 in a comb shape of which position of the inside root of two oscillating arms each on inside and outside to the support member 11, or 111 in the oscillating arm direction is matched or different are used in the driving side tuning for, while inner two oscillating arms 13, 14, or 113, 114 are used in the detecting side tuning fork so as to correspond between driving and detection.
-
Citations
16 Claims
-
1. An angular velocity sensor formed from crystal material having crystal axes, said crystal axes including an electrical axis, a mechanical axis, and an optical axis,
said angular velocity sensor comprising four parallel oscillating arms and a first and second support member for commonly holding the four parallel oscillating arms at both ends of each of the four parallel oscillating arms, said angular velocity sensor configured such that a base of said annular velocity sensor extending along a width of said angular velocity sensor is positioned on said electrical axis, a direction along a length of said angular velocity sensor forms an angle θ - with said mechanical axis and a direction along a depth of said angular velocity sensor forms the same angle θ
with said optical axis,two of said four oscillating arms defining a driving side tuning fork and the other two of said four oscillating arms defining a detecting side tuning fork, wherein each of the two oscillating arms of the detecting side tuning fork being cut in a middle portion of a respective oscillating arm such that each of said two oscillating arms of said detecting side tuning fork comprises a first and a second oscillating arm, said first oscillating arm of each of said two oscillating arms of said detecting side tuning fork extending from said first support member and said second oscillating arm of each of said two oscillating arms of said detecting side tuning fork extending from said second support member, each of said first and second oscillating arms of each of said two oscillating arms of said detecting side tuning fork being positioned either outside or inside of said two oscillating arms of said driving side tuning fork, said angular velocity sensor further comprising driving electrodes positioned on face and back surfaces or side surfaces of the driving side tuning fork and detecting electrodes positioned on face and back surfaces or side surfaces of the detecting side tuning fork such that applying an alternating-current power to the driving electrodes in either or both oscillating arms of the driving side tuning fork generates and maintains a width direction flexural oscillation in mutually reverse phases on the driving side tuning fork, wherein when an angular velocity vector rotating and acting on the entire angular velocity sensor is applied from outside, said angular velocity sensor detects an electric charge generated in the detecting electrodes by a thickness direction flexural oscillation in mutually reverse phases on the detecting side tuning fork induced from a driving force of a thickness direction component of Coriolis force acting in an oscillating portion in the width direction of the driving side tuning fork or detecting side tuning fork, thereby obtaining an electrical signal in proportion to an input angular velocity. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- with said mechanical axis and a direction along a depth of said angular velocity sensor forms the same angle θ
-
10. An angular velocity sensor formed from a crystal material, comprising:
-
six oscillating arms, wherein two of said oscillating arms form a driving side tuning fork and four of said oscillating arms form a detecting side tuning fork;
first and second support members for coupling to said six oscillating members, wherein said six oscillating members are positioned between said first and second support members;
driving electrodes for coupling to said driving side tuning fork and adapted to receive an AC power signal; and
detecting electrodes for coupling to said detecting side tuning fork and adapted to output a detecting signal corresponding to an input angular velocity. - View Dependent Claims (11, 12, 13, 14, 15, 16)
-
Specification