Abstract:
A motion sensor in the form of an angular rate sensor (10) and a method of making a sensor are provided and includes a support substrate (12) and a silicon sensing ring (14) supported by the substrate and having a flexural resonance. Drive electrodes (20A) apply electrostatic force on the ring (14) to cause the ring to resonate. Sensing electrodes (20B) sense a change in capacitance indicative of vibration modes of resonance of the ring (14) so as to sense motion. A plurality of silicon support rings (16) connect the substrate (12) to the ring (14). The support springs (16) have portions (B1 and B2) are located at an angle to substantially match a modulus of elasticity of the silicon, such as about 22.5° and 67.5°, with respect to the crystalline orientation of the silicon. Also disclosed is a method of making a silicon integrated sensor.
Abstract:
A balanced angular accelerometer (10;110) is provided having a substrate (60), a fixed electrode (20A) with a plurality of fixed capacitive plates (24), and a rotational inertia mass (12) with a central opening (13) and substantially suspended over a cavity (34) and including a plurality of movable capacitive plates (14) arranged to provide a capacitive coupling with the first plurality of fixed capacitive plates (24). The accelerometer (10) has a central member (15) and an outer member (18) fixed to the substrate (60). According to one embodiment, a plurality of inner support arms (16A-16D) extend between the central member (15) and the inertia mass (12) and a plurality of outer support arms (40A-40D) extend between the inertia mass (12) and the outer member (18) to support the mass (12) over the cavity (34).
Abstract:
A motion sensor (10) includes a micromachined sensing structure and a number of capacitive electrodes (20) disposed about a periphery thereof. The sensing structure includes a ring (14) supported above a substrate (12) so as to have an axis of rotation normal to the substrate (12), and a number of springs (16) attached to a post (18) positioned at the center of the ring (14). Certain diametrically opposed ones of the capacitive electrodes (20) are configured as drive electrodes (20a), and other diametrically opposed ones of the capacitive electrodes (20), positioned 90 degrees relative to the corresponding drive electrodes (20a) are configured as sense electrodes (20b). Signals produced at the opposed sense electrodes (20b) are conditioned and coupled to a common input of an amplifier circuit (64,70). With the configuration of the drive (20a) and sense (20b) electrodes and supporting circuitry (60-70), the resulting sensor (10) is operable to reject the effects of linear forces thereupon due to road vibrational effects.
Abstract:
A strain gauge (10) for sensing strain is provided and includes a support substrate (40), and first and second electrodes (20A and 12) supported on the substrate (40). The first and second electrodes (20A and 12) include first and second capacitive plates (24 and 14), respectively. The first capacitive plates (24) are movable relative to the second capacitive plates (14) responsive to strain. The strain gauge (10) further has an input (26) electrically coupled to one of the first and second electrodes (20A and 12) for receiving an input signal (CLK), and an output (30) electrically coupled to the other of the first and second electrodes (20A and 12) for providing an output signal (V oi ) which varies as a function of the capacitive coupling and is indicative of sensed strain.
Abstract:
A balanced angular accelerometer (10 or 110) is provided having a substrate (60), a fixed electrode (20A) with a plurality of fixed capacitive plates (24), and a rotational inertia mass (12) with a central opening (13) and substantially suspended over a cavity (34) and including a plurality of movable capacitive plates (14) arranged to provide a capacitive coupling with the first plurality of fixed capacitive plates (24). The accelerometer (10) has a central member (15) and an outer member (18) fixed to the substrate (60). According to one embodiment, a plurality of inner support arms (16A-16D) extend between the central member (15) and the inertia mass (12) and a plurality of outer support arms (40A-40D) extend between the inertia mass (12) and the outer member (18) to support the mass (12) over the cavity (34). According to another embodiment, one or more cut out apertures (150) are formed in the inertia mass (112) to compensate for a channel (141) and signal line (140) so as to balance the inertia mass (112) about the center of the inertia mass (112).
Abstract:
A balanced angular accelerometer (10 or 110) is provided having a substrate (60), a fixed electrode (20A) with a plurality of fixed capacitive plates (24), and a rotational inertia mass (12) with a central opening (13) and substantially suspended over a cavity (34) and including a plurality of movable capacitive plates (14) arranged to provide a capacitive coupling with the first plurality of fixed capacitive plates (24). The accelerometer (10) has a central member (15) and an outer member (18) fixed to the substrate (60). According to one embodiment, a plurality of inner support arms (16A-16D) extend between the central member (15) and the inertia mass (12) and a plurality of outer support arms (40A-40D) extend between the inertia mass (12) and the outer member (18) to support the mass (12) over the cavity (34). According to another embodiment, one or more cut out apertures (150) are formed in the inertia mass (112) to compensate for a channel (141) and signal line (140) so as to balance the inertia mass (112) about the center of the inertia mass (112).
Abstract:
A strain gauge (10) for sensing strain is provided and includes a support substrate (40), and first and second electrodes (20A and 12) supported on the substrate (40). The first and second electrodes (20A and 12) include first and second capacitive plates (24 and 14), respectively. The first capacitive plates (24) are movable relative to the second capacitive plates (14) responsive to strain. The strain gauge (10) further has an input (26) electrically coupled to one of the first and second electrodes (20A and 12) for receiving an input signal (CLK), and an output (30) electrically coupled to the other of the first and second electrodes (20A and 12) for providing an output signal (V oi ) which varies as a function of the capacitive coupling and is indicative of sensed strain.