A collision deformation sensor for use within the crush zone of a vehicle consists of first and second spaced apart substrates for mounting to or forming respective vehicle components, with a compressible carrier medium filling the space between the substrates. The carrier medium is formed from a material transparent or translucent to light or other wave energy, and includes wave energy scattering centers dispersed within the medium to create a scattered energy volume. Alternatively the carrier medium forms a hollow cavity, the inside surface of which is coated with a wave energy dispersion coating. A source and receiver of light or other wave energy communicates with the carrier medium. Signal couplings and processors are associated with the source and receiver. The device operates on the principle whereby compression of the space between the substrates increases the intensity of a light or other wave energy, and this increase is detected by the receiver and signal processor, which in turn activates an air bag, or seat belt tightener or the like.

Collision deformation sensor using a source of wave energy for use in the crush zone of a vehicle

A three-axis accelerometer is provided for sensing acceleration in three orthogonal axes. The accelerometer includes a support substrate, fixed electrodes having fixed capacitive plates fixed to the support substrate, and a movable inertial mass having movable capacitive plates capacitively coupled to the fixed capacitive plates. The accelerometer includes banks of fixed and movable capacitive plates oriented to sense acceleration in orthogonal X- and Y-axes. Additionally, the accelerometer includes fixed and movable capacitive plates having a height variation between adjacent plates to sense acceleration in the vertical Z-axis. Input signals are applied to certain electrodes coupled to the fixed capacitive plates, and an output signal is generated on the inertial mass, which is indicative of acceleration in each of the sensing axes. The output signal may be further processed to generate individual acceleration outputs for each of the sensing axes.

Multiple-axis linear accelerometer

A silicon-based microaccelerometer for seismic application is provided using a low-resonant frequency (10 Hz), large proof mass (1 gram), and high Q suspension to achieve high sensitivity of less than 1 ng with a bandwidth a 0.05 to 50 Hz. The proof mass is cut away from a planar substrate in the form of a disk using abrasive cutting, which disk closely fits but does not touch a surrounding angular frame. The spring of the microaccelerometer between the angular frame and the proof mass is provided from two continuous, 3 microns thick membranes. The fixed capacitive electrodes are provided on separate, subsequently bonded substrates, and movable capacitive plates are provided on the membranes. By fabricating capacitive plates on the separate substrates, the gap between the fixed and movable capacitive plates in the differential capacitive sensor is closely controlled. The use of continuous membranes for the spring produces a shock resistant, robust sensor.

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Silicon micromachined accelerometer/seismometer and method of making the same

A MEMS sensor includes a substrate having a MEMS structure movably attached to the substrate, a cap attached to the substrate and encapsulating the MEMS structure, and an electrode formed on the cap that senses movement of the MEMS structure.

MEMS Sensor with Cap Electrode

A balanced angular accelerometer is provided having a substrate, a fixed electrode with a plurality of fixed capacitive plates, and a rotational inertia mass with a central opening and substantially suspended over a cavity and including a plurality of movable capacitive plates arranged to provide a capacitive coupling with the first plurality of fixed capacitive plates. The accelerometer has a central member and an outer member fixed to the substrate. According to one embodiment, a plurality of inner support arms extend between the central member and the inertia mass and a plurality of outer support arms extend between the inertia mass and the outer member to support the mass over the cavity. According to another embodiment, one or more cut out apertures are formed in the inertia mass to compensate for a channel and signal line so as to balance the inertia mass about the center of the inertia mass.

Angular accelerometer having balanced inertia mass

A capacitive acceleration sensor is composed of a silicon plate, a glass plate and a substrate The silicon plate has a fixed portion and a movable portion supported by the fixed portion through spring beams The movable portion is moved in response to the change in the acceleration and is provided with a moving electrode thereon The glass plate is provided with a fixed electrode and anodically bonded to the silicon plate so that the fixed electrode faces the moving electrode with a predetermined gap On the glass plate, a first dummy electrode is formed at a location corresponding to the spring beams of the silicon plate The dummy electrode has a terminal portion at one end so as to be electrically connected with the silicon plate during anodic bonding of the plates On the substrate, a second dummy electrode is formed at a location corresponding to the movable portion of the silicon plate The dummy electrode, similarly, has a terminal portion at one end so as to be electrically connected with the silicon plate during anodic bonding of the silicon plate and the substrate

Nakane Kunie

Papers

Capacitive sensor for detecting a physical value such as acceleration