Provided is an acceleration sensor capable of realizing a simultaneous operation method of signal detection and servo control in place of a time-division processing method, by an MEMS process in which a manufacturing variation is large.

The acceleration sensor is an MEMS capacitive acceleration sensor and has capacitive elements for signal detection and capacitive elements for servo control different from the capacitive elements for the signal detection. A voltage to generate force in a direction reverse to a detection signal of acceleration by the capacitive elements for the signal detection is applied to the capacitive elements for the servo control. Further, the acceleration sensor includes a variable capacity unit compensating for a mismatch of capacity values of the capacitive elements for the servo control at an ASIC side, detects a leak signal due to the mismatch of the capacity values in an ASIC, controls a capacity value of the variable capacity unit, on the basis of a detection result, compensates for an influence of the mismatch of the capacity values, and executes a normal signal detection/servo control simultaneous operation.

An accelerometer sensor includes a casing, a pendulum fixed to the casing, a movable electrode carried by the pendulum and connected to a detection circuit, a first electrode and a second electrode rigidly attached to the casing to form, with the moving electrode, two capacitors of variable capacitance depending on a distance between the electrodes. The accelerometer sensor further includes a control unit that carries out detection operations to measure the variable capacitances of the capacitors. The control unit also performs a control operation of the movable electrode depending on the capacitances measured by applying a logic signal for controlling a switch for selective connection of the fixed electrodes to an excitation circuit delivering a control signal to the fixed electrodes in order to keep the pendulum in a predetermined position.

A closed-loop microelectromechanical accelerometer includes a substrate of semiconductor material, an out-of-plane sensing mass and feedback electrodes. The out-of-plane sensing mass, of semiconductor material, has a first side facing the supporting body and a second side opposite to the first side. The out-of-plane sensing mass is also connected to the supporting body to oscillate around a non-barycentric fulcrum axis parallel to the first side and to the second side and perpendicular to an out-of-plane sensing axis. The feedback electrodes are capacitively coupled to the sensing mass and are configured to apply opposite electrostatic forces to the sensing mass.

An example system comprising: a microelectromechanical system (MEMS) vibrating beam accelerometer (VBA) comprising: a proof mass; and a first resonator mechanically coupled to the proof mass; a first electrode configured to apply a force to the proof mass.

The purpose of the present invention is to provide a method for manufacturing a three-dimensionally structured member which can be made by a simpler process. The method for manufacturing a three-dimensionally structured member includes shaping a flat plate-shaped base member to produce a three-dimensionally structured member having a plurality of sections that are different from one another in thickness. The manufacturing method comprises: a mask formation step for forming a mask over the whole of at least one main surface of the base member; a mask removal step for removing a part of the mask; and an etching step for etching an exposed part of the base member wherein a combination of the mask removal step and the etching step is performed on the mask and the base member that correspond to each of the plurality of sections of the three-dimensionally structured member, in the order from thinnest to the thickest of thicknesses of the three-dimensionally structured members.

There is provided a resonant sensor comprising: a substrate; a proof mass suspended from the substrate by one or more flexures to allow the proof mass to move relative to the frame along a sensitive axis; a first and a second resonant element connected between the frame and the proof mass; wherein the proof mass is positioned between the first and the second resonant element along the sensitive axis, and wherein the first and the second resonant elements have a substantially identical structure to one another; and drive and sensing circuitry comprising: a first electrode assembly coupled to first drive circuitry configured to drive the first resonant element in a first mode; a second electrode assembly coupled to second drive circuitry configured to drive the second resonant element in a second mode, different to the first mode; and a sensing circuit configured to determine a measure of acceleration.

A capacitive accelerometer includes a proof mass, first and second fixed capacitive electrodes, and a DC biasing element arranged to apply a DC voltage (V.sub.B) to the proof mass based on a threshold acceleration value. A first closed loop circuit is arranged to detect a signal resulting from displacement of the proof mass and control the pulse width modulation signal generator to apply the first and second drive signals V.sub.1, V.sub.2 with a variable mark:space ratio. A second closed loop circuit keeps the mark:space ratio constant and to change the magnitude, V.sub.B, of the DC voltage applied to the proof mass by the DC biasing element so as to provide a net electrostatic restoring force on the proof mass for balancing the inertial force of the applied acceleration and maintaining the proof mass at a null position, when the applied acceleration is greater than a threshold acceleration value.

A semiconductor structure includes a substrate; a sensing device disposed over the substrate and including a plurality of protruding members protruded from the sensing device; a sensing structure disposed adjacent to the sensing device and including a plurality of sensing electrodes protruded from the sensing structure towards the sensing device; and an actuating structure disposed adjacent to the sensing device and configured to provide an electrostatic force on the sensing device based on a feedback from the sensing structure. Further, a method of manufacturing the semiconductor structure is also disclosed.

A motion sensing system uses high-voltage biasing to achieve high resolution with ultra-low power. The motion sensing system consists of a motion sensor, a readout circuit, and a high-voltage bias circuit to generate the optimized bias voltage for the motion sensor. By using the high-voltage bias, the signal from the motion sensor is raised above the readout circuit's noise floor, eliminating the power-hungry amplifier and signal-chopping used in conventional motion sensing systems. The bias circuit, while producing the programmable bias voltages for the motion sensor, also compensates for the process mismatch raised by the high voltage biases.

The invention relates to an acceleration sensor (400) comprising an excitation mass (420) having excitation electrodes (430), which excitation mass is movably mounted over a substrate (410) along a movement axis (x) and comprising detection electrodes (440) which are permanently connected to the substrate (410) and allocated to the excitation electrodes (430). A first group of pairings (450) of excitation electrode (430) and allocated detection electrodes (440) is suitable for deflecting the excitation mass (420) along the movement axis (x) in a first direction (460). A second group of pairings (450) of excitation electrodes (430) and allocated detection electrodes (440) is suitable for deflecting the excitation mass (420) along the movement axis (x) in a second direction (465), which is opposite the first direction (460). The number of pairings (450) in the first group is equal to the number of pairings (450) in the second group. The averaged distance between excitation electrodes (430) and detection electrodes (440) of the pairings (450) of the first group corresponds to the averaged distance between excitation electrodes (430) and detection electrodes (440) of the pairings (450) of the second group.