Angular rate sensor and acceleration sensor

• US 5,952,572 A
• Filed: 01/17/1997
• Issued: 09/14/1999
• Est. Priority Date: 01/19/1996
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamashita, Mitsuhiro, Esashi, Masayoshi
• Primary Examiner(s): Oda, Christine K.
• Application Number:
  US08/784,405
• Time in Patent Office: 970 Days
• Field of Search: 73/504.16, 73/504.12, 73/504.14, 73/504.02, 73/504.15, 73/514.32, 73/514.33, 73/514.34, 73/504.04, 73/514.29, 310/329, 310/321, 310/316, 310/332
• US Class Current: 73/504.04
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 15/125 by capacitive pick-up
• CPC Class Codes: G01P 2015/0828 the mass being of the paddle type being suspended at one of its longitudinal ends
• CPC Class Codes: G01P 2015/084 the mass being suspended at more than one of its sides, e.g. membrane-type suspension, so as to permit multi-axis movement of the mass
• CPC Class Codes: G01P 2015/0842 the mass being of clover leaf shape

Abstract

The sensor is a small-sized vibratory angular velocity sensor, and making use of anisotropic etching characteristics of single crystal silicon substrate, as shown in FIG. 1, four cantilever beams 103 of leading end load (masses 102) type are disposed in a cross form, and the center of gravity (coupling portion 104) thereof is supported by a bridge 105 to form a vibrator, which is excited by electrostatic force by utilizing electrodes 110, 115 formed above and below the end portion of the masses 102, and the angular rate is detected from the capacitance change.

Claims

1. A sensor for detecting angular rate or acceleration comprising:

a vibrator having

at least two masses, formed from a single crystal silicon substrate having a principal surface thereof formed in a (110) crystal plane, and

at least two beams for supporting the masses, each of the at least two beams having a principal surface thereof formed in a (111) crystal plane which is vertical relative to the principal surface of the silicon substrate, such that the beams have flexibility in a plane that is parallel to the principal surface of the silicon substrate; and

electrodes for driving the vibrator.

2. A sensor for detecting angular rate or acceleration as recited in claim 1, wherein said vibrator further includes a beam having a principal surface thereof formed in a (110) crystal plane parallel to the principal surface of the silicon substrate.

5. A sensor for detecting angular rate or acceleration as recited in claim 1, wherein said vibrator is formed by crystallographic anisotropic etching or reactive ion etching.

3. A sensor for detecting angular rate or acceleration comprising:

a vibrator having

at least two masses formed from a single crystal silicon substrate having a principal surface thereof formed in a (100) crystal plane, and

at least two beams for supporting the masses, each of the at least two beams having a principal surface thereof formed in a (100) crystal plane which is vertical relative to the principal surface of the silicon substrate, such that the at least two beams have flexibility in a plane that is parallel to the principal surface of the silicon substrate; and

electrodes for driving the vibrator.

4. A sensor for detecting angular rate or acceleration as recited in claim 3, wherein said vibrator further includes a beam having a principal surface thereof formed in a (100) crystal plane parallel to the principal surface of the silicon substrate.

6. A sensor for detecting angular rate or acceleration as recited in claim 3, wherein said vibrator is formed by crystallographic anisotropic etching or reactive ion etching.