117 results about "Capacitive accelerometer" patented technology

A multi-axis accelerometer is consisted of a substrate with sensing electrodes and a structure layer. The structure layer includes anchor bases fixed on the substrate. A first proof mass is disposed over the substrate and has a first opening and a second opening symmetric to each other. The first proof mass is suspended to the anchor bases. Fixed sensing blocks are disposed on the substrate, and capacitors are formed between each fixed sensing block and the first proof mass for sensing acceleration along two in-plane directions. A second proof mass and a third proof mass are disposed in the first opening and the second opening and are asymmetrically suspended. Separate electrodes are disposed on the substrate and form two differential capacitors with the second proof mass and the third proof mass for sensing the out-of-plane acceleration.

A multi-axis accelerometer is consisted of a substrate with sensing electrodes and a structure layer. The structure layer includes anchor bases fixed on the substrate. A first proof mass is disposed over the substrate and has a first opening and a second opening symmetric to each other. The first proof mass is suspended to the anchor bases. Fixed sensing blocks are disposed on the substrate, and capacitors are formed between each fixed sensing block and the first proof mass for sensing acceleration along two in-plane directions. A second proof mass and a third proof mass are disposed in the first opening and the second opening and are asymmetrically suspended. Separate electrodes are disposed on the substrate and form two differential capacitors with the second proof mass and the third proof mass for sensing the out-of-plane acceleration.

A pendulous capacitive accelerometer including a substrate having a substantially planar upper surface with an electrode section, and a sensing plate having a central anchor portion supported on the upper surface of the substrate to define a hinge axis. The sensing plate includes a solid proof mass on a first side of the central anchor portion and a substantially hollow proof mass on a second side of the central anchor portion, providing for reduced overall chip size and balanced gas damping. The solid proof mass has a first lower surface with a first electrode element thereon, and the substantially hollow proof mass has a second lower surface with a second electrode element thereon. Both the solid proof mass and the hollow proof mass have the same capacitive sensing area. The sensing plate rotates about the hinge axis relative to the upper surface of the substrate in response to an acceleration.

The invention provides a built-in self test circuit for a parallel plate capacitive MEMS (Micro-Electro-Mechanical-System) accelerometer and a self test method. Electric excitation is provided for the parallel plate capacitive accelerometer, signals outputted by a capacitive sensing module are simplified and subjected to analog-to-digital conversion and digital processing, the sensitivity S is analyzed according to self test power supply voltages V1 and V2 in different conditions and an output response Vc of the capacitive sensing module, technical defects of the parallel plate capacitive MEMS accelerometer are then diagnosed, and built-in self test is carried out on the sensitivity S of the capacitive accelerometer. Influences on output signals by the external environment and parasitic capacitance are optimized, the test standardization degree is improved, dependence on a complicated test instruction is reduced, and the test cost and the product cost are effectively reduced.

The invention discloses a temperature compensating device for a micro-machined capacitive accelerometer. The temperature compensating device mainly comprises a coherent demodulator, a low pass filter and a temperature compensating circuit, wherein an output end of the coherent demodulator is connected with an input end of the low pass filter; and the output end of the low pass filter is connectedwith the input end of the low temperature compensating circuit. By taking the internal capacitance which changes with the temperature of the micro-machined capacitive accelerometer as a compensating reference signal of an output signal of the accelerometer, the temperature compensating device does not need a thermistor or an integrated temperature sensor for measuring the temperature of an acceleration sensor, so the structure of the temperature compensating device is simplified, and the cost is reduced; the influence on compensating precision due to temperature measurement error is eliminated, and the temperature compensating precision is improved; and no temperature sensor is needed to be arranged and used on the micro-machined capacitive accelerometer, so a temperature measurement error due to a temperature gradient of a metal pipe shell of the acceleration sensor is avoided, and the temperature compensating precision is further improved.

A comb capacitive accelerometer comprising a substrate, a mobile electrode relative to said substrate fitted with a plurality of mobile fingers, an electrode fixed relative to said substrate fitted with a plurality of fixed fingers, each of said mobile fingers being positioned between two contiguous fixed fingers so as to form a microstructure with interdigital combs. According to the invention the mobile fingers are connected to one another by at least a first connecting beam etched directly into the substrate, and / or the fixed fingers are connected to one another by at least a second connecting beam etched directly in the substrate.

A system for determining in-plane acceleration of an object. The system includes an in-plane accelerometer with a substrate rigidly attached to an object, and a proof mass—formed from a single piece of material—movably positioned a predetermined distance above the substrate. The proof mass includes a plurality of electrode protrusions extending downward from the proof mass to form a gap of varying height between the proof mass and the substrate. The proof mass is configured to move in a direction parallel to the upper surfaces of each of the plurality of substrate electrodes when the object is accelerating, which results in a change in the area of the gap, and a change in capacitance between the substrate and the proof mass. The in-plane accelerometer can be fabricated using the same techniques used to fabricate an out-of-plane accelerometer and is suitable for high-shock applications.

A multi-axis capacitive accelerometer is disclosed. A first mass is disposed and held by an anchor supported by a substrate, wherein the first mass is asymmetrically suspended on the anchor by means of two cantilevers, so that the first mass rotates about a rotation axis, for sensing the acceleration in a first direction perpendicular to the substrate. A second mass is disposed in the first mass and suspended on the first mass by means of a set of springs to sense the acceleration in a second direction parallel to the substrate. Furthermore, a third mass can be disposed in the second mass, wherein the third mass is suspended on the second mass by means of another set of springs to sense the acceleration in a third direction. The first direction, the second direction and the third direction are mutually orthogonal to each other.

A capacitive accelerometer having one or more micromachined acceleration sensor assembly is disclosed. The acceleration sensor assembly comprises a spring-mass-support structure, a top cap and a bottom cap. The proof mass plate of the spring-mass-support structure has cutout spaces and is supported by a pair of branched torsional beams which are substantially located in the cutout spaces. The torsional axis of the proof mass plate is offset from the mass center in direction perpendicular to the proof mass plate. The acceleration sensor assembly further comprises multiple coplanar electrodes for differential capacitive sensing and electrostatic forcing. The capacitive accelerometer according to the present invention may comprise one, two or six micromachined acceleration sensor assemblies with electronic signal detection, conditioning and control circuits in different configurations and applications to detect and measure linear and angular accelerations. Methods to fabricate the micromachined acceleration sensor assembly are disclosed.

There is provided a bidirectional readout circuit for detecting direction and amplitude of an oscillation sensed at a capacitive microelectromechanical system (MEMS) accelerometer, the bidirectional readout circuit converting capacitance changes of the capacitive MEMS accelerometer into a time change amount by using high resolution capacitance-to-time conversion technology and outputting the time change amount as the direction and the amplitude of the oscillation by using time-to-digital conversion (TDC) technology, thereby detecting not only the amplitude of the oscillation but also the direction thereof, which is capable of being applied to various MEMS sensors.

The invention relates to a manufacturing method for a quartz comb teeth capacitive accelerometer. The accelerometer comprises an upper cover plate, a lower cover plate and sensitive components. The manufacturing method refers to manufacturing of the sensitive components, manufacturing of the upper cover plate and the lower cover plate and bonding between the upper cover plate and the lower cover plate. According to the method, quartz materials are adopted in manufacturing of the teeth capacitive accelerometer for the first time, the manufacturing method aiming at the specific structure of the accelerometer is innovatively designed, and new purposes of the quartz materials are achieved. The whole structure of the capacitive accelerometer is made of the quartz materials, thermal expansion coefficient is matched with the accelerometer, temperature performance of sensors can be improved, great sensing masses and initial capacitance values can be obtained, sensitivity and resolution of the sensors can be obviously improved, and it is ensured that manufactured comb teeth have large depth-to-width ratios.

A micromechanical structure for a MEMS structure is provided with: a substrate; a single inertial mass having a main extension in a plane and arranged suspended above the substrate; and a frame element, elastically coupled to the inertial mass by coupling elastic elements and to anchorages, which are fixed with respect to the substrate by anchorage elastic elements. The coupling elastic elements and the anchorage elastic elements are configured so as to enable a first inertial movement of the inertial mass in response to a first external acceleration acting in a direction lying in the plane and also a second inertial movement of the inertial mass in response to a second external acceleration acting in a direction transverse to the plane.

A Z-axis capacitive accelerometer includes a substrate, a capacitance sensing plate, a proof mass and at least one pair of spring beams. The capacitance sensing plate includes two symmetrical sense areas to create differential capacitive measurement. A decoupling structure separates the proof mass and the capacitance sensing plate and their rotational motions from each other. In the proposed Z axis capacitive accelerometer, the distance of the capacitance sensing plate relative to its rotation axis is considerably increased, thereby effectively enhancing the sensitivity when measuring the Z-axis acceleration.

A capacitance accelerometer includes a housing, and a plate fixed within the housing. A moveable plate is disposed in substantially parallel relation to the fixed plate and is coupled to the housing along at least an edge. The moveable plate and the fixed plate define a distance. The distance varies in response to acceleration forces acting upon the moveable plate, and wherein the moveable plate and the fixed plate generate a charge displacement capacitance signal. A transimpedance amplifier receives the charge displacement capacitance signal and generates a scaled voltage signal therefrom. An acceleration signal is generated from the scaled voltage signal.