Abstract:
A novel Si MEMS piezoresistive resonator is described. The resonator has a shape of a frame, such as a ring or a polygon frame, which has two or more anchors. Electrodes located at the outer or inner rim of the resonant structure are used to excite the structure electrostatically into resonance with a desired mode shape. One or plurality of locally doped regions on the structure is used for piezoresistive readout of the signal. In the most preferred embodiments, the structure is a ring, which has four anchors, two electrodes and four piezoresistive regions at different segments of the structure. The piezoresistive regions are alternatively located at the outer rim and inner rim of the structure in such a way that the piezoresistive signals of the same sign from different regions can be collected. Advantages of this device are large readout signal, large electrode area, robustness, suppressed out-of-plane vibration and larger usable linear range.
Abstract:
The present invention relates to a detection system for the detection of movements of a movable object. The detection system may comprises: a light emitting device (S) for emitting light, a reflecting unit (5) being arranged in functional connection with the movable object and being adapted for reflecting the emitted light, a plurality of detectors (D1 to D4) for detecting the reflected light and outputting detection signals for determining a movement of the movable object. When reflecting the emitted light, the reflecting unit causes a light spot to be incident on the plurality of detectors, and the plurality of detectors are arranged in a predetermined manner so as to be located completely inside the light spot irrespective of any movement of the movable object. The present invention further relates to a method of detecting movements of the movable object, and an IC having implemented therein the detection system.
Abstract:
A resonator comprises a resonator mass (34), a first connector (30) on a first side of the mass connected between the resonator mass and a first fixed mounting and a second connector (32) on a second, opposite, side of the mass connected between the resonator mass and a second fixed mounting. Drive means drives the mass (34) into a resonant mode in which it oscillates in a sideways direction, thereby compressing one of the first and second connectors while extending the other of the first and second connectors.
Abstract:
A pressure/vacuum sensor and method, comprising: driving a MEMS piezoresistive resonator (8) into resonant vibration, applying Joule heating to the resonator (8); and sensing a variable parameter that varies in response to the tendency of the resonant frequency (fo) to depend upon the temperature of the resonator (8), the temperature thereof depending upon the pressure. The variable parameter may be the resonant frequency of the resonator (8), or a change therein, or may be derived from a feedback loop, being for example a time integrated feedback signal (82) or a reading (94) of the sense current (22), the loop keeping the resonant frequency constant in opposition to the above mentioned tendency. A reference MEMS capacitive resonator (62) may be located in the vicinity of the resonator (8) for compensating purposes.
Abstract:
Consistent with an example embodiment, devices comprise sensor arrangements with field detectors for detecting components of magnetic fields in planes of the field detectors. The sensor arrangements further include movable objects for, in response to tilting movements, changing at least parts of the components of the magnetic fields in the planes of the field detectors so that the sensor arrangements are made less sensitive to in-plane stray fields by providing the field detectors with saturated field-dependent elements. The movable object may comprise a movable field generator for generating the magnetic field, or the movable object and the field generator may be different objects. The magnetic field is such that the field-dependent element is saturated. The field generator is smaller than the field detector, and the movable object is larger than the field detector, to reduce alignment problems. The movable object has a pivoting point close to the field detector.
Abstract:
Devices (1) are provided with sensor arrangements (2) comprising field generators (10) for generating magnetic fields and first/second/third field detectors (11,12,13) comprising first/second/third elements (R1-R4, S1-S4, T1-T4) for detecting first/second/third components of the magnetic fields in a plane and movable objects (14) for, in response to first/second/third accelerations of the movable objects (14) in first/second/third directions, changing the first/second/third components of the magnetic fields (11,12,13) is more sensitive to the first (second, third) acceleration than to the other accelerations. Such devices (1) have a good sensitivity and a good linearity. The elements (R1-R4, S1-S4, T1-T4) form part of bridges. The first elements (R1-R4) surround the second and third elements (S1-S4, T1-T4), or vice versa. The first elements (R1-R4) may be in round or rectangular form and the second and third elements (S1-S4, T1-T4) may be in the form of sun beams leaving a sun. The first elements are non-saturated barberpole magnetoresistive elements measuring the field strength which varies in response to accelerations in a direction perpendicular to the plane. The second and third elements are saturated barberpole magnetoresistive elements measuring changes in the direction of the magnetic field in response to accelerations in directions parallel to the plane.
Abstract:
Devices (40) are provided with sensor arrangements (41) comprising field generators (42) for generating magnetic fields, field detectors (43) comprising magnetic field dependent elements (51-58) for detecting components of the magnetic fields in planes of the elements (51-58), and movable objects (44) for, in response to accelerations of the movable objects (44) parallel to the planes, changing the components of the magnetic fields. Length axes of the magnetic field dependent elements (51-58) make angles between minus 80 degrees and plus 80 degrees with the components to be detected. Means for forcing the movable objects (44) into rest positions comprise elastic material (59) or fixed objects (46) whereby one of the objects (44,46) comprises the field generator (42) and the other comprises magnetic material or a further field generator (50).
Abstract:
The present invention concerns a detection system and a corresponding method for detecting movements of a movable object that compensate for unintentional tilt movement of the movable object in a first direction and/or in a second direction when a linear movement in a third direction is detected.
Abstract:
The present invention relates to a detection system for the detection of movements of a movable object. The detection system may comprises: a light emitting device (S) for emitting light, a reflecting unit (5) being arranged in functional connection with the movable object and being adapted for reflecting the emitted light, a plurality of detectors (D1 to D4) for detecting the reflected light and outputting detection signals for determining a movement of the movable object. When reflecting the emitted light, the reflecting unit causes a light spot to be incident on the plurality of detectors, and the plurality of detectors are arranged in a predetermined manner so as to be located completely inside the light spot irrespective of any movement of the movable object. The present invention further relates to a method of detecting movements of the movable object, and an IC having implemented therein the detection system.
Abstract:
A MEMS resonator has a component which provides a capacitance associated with the transduction gap which has a temperature-dependent dielectric characteristic, which varies in the same direction (i.e. the slope has the same sign) as the Young's modulus of the material of the resonator versus temperature. This means that the resonant frequency is less dependent on temperature.