Abstract: In a method for fabricating an electrostatic capacitance-type acceleration sensor having a capacitor which electrostatic capacitance between a movable electrode and a fixed electrode changes according to the displacement of the movable electrode, the method includes: a step of forming a groove on at least one of the surface of an insulative substrate and the surface of a semiconductor substrate; a step of forming a hole in the semiconductor substrate so as to penetrate the semiconductor substrate at a position communicating with a passage formed by the groove; and a step of forming an electrode extraction hole in the insulative substrate so as to penetrate the insulative substrate, at a position communicating with the passage formed by the groove.

Abstract: An acceleration sensor circuit 1 of the invention includes an acceleration sensor 11 having a first capacitor C1 whose capacitance changes according to a position of a first movable electrode and a second capacitor C2 whose capacitance changes as opposed to the first capacitor according to a position of a second movable electrode moved together with the first movable electrode, a first circuit 15A for generating a sinusoidal AC signal of a predetermined frequency, a second circuit 12 for generating a signal according to the positions of the movable electrodes, and an arithmetic circuit 14 for analyzing data in which a signal generated by the second circuit 12 is encoded and outputting data of acceleration.

Abstract: A pseudo rock includes a housing, a strain sensor, a three-axis acceleration sensor, a vibration generator and a controller. The housing has an average shape and size of rocks. The strain sensor detects a stress acting in positive and negative directions of each axis with respect to three-dimensional coordinates using the center of the housing as the origin. The three-axis acceleration sensor detects acceleration acting in each axis of the three-dimensional coordinates. The vibration generator produces vibration in a specific direction with respect to the three-dimensional coordinates. The controller converts respective detected values of the strain sensor and the three-axis acceleration sensor into vibration pulses of specific patterns and outputting the vibration pulses to the vibration generator.

Abstract: In a method for fabricating an electrostatic capacitance-type acceleration sensor having a capacitor which electrostatic capacitance between a movable electrode and a fixed electrode changes according to the displacement of the movable electrode, the method includes: a step of forming a groove on at least one of the surface of an insulative substrate and the surface of a semiconductor substrate; a step of forming a hole in the semiconductor substrate so as to penetrate the semiconductor substrate at a position communicating with a passage formed by the groove; and a step of forming an electrode extraction hole in the insulative substrate so as to penetrate the insulative substrate, at a position communicating with the passage formed by the groove.

Abstract: An acceleration sensor circuit 1 of the invention includes an acceleration sensor 11 having a first capacitor C1 whose capacitance changes according to a position of a first movable electrode and a second capacitor C2 whose capacitance changes as opposed to the first capacitor according to a position of a second movable electrode moved together with the first movable electrode, a first circuit 15A for generating a sinusoidal AC signal of a predetermined frequency, a second circuit 12 for generating a signal according to the positions of the movable electrodes, and an arithmetic circuit 14 for analyzing data in which a signal generated by the second circuit 12 is encoded and outputting data of acceleration.

Abstract: A pseudo rock includes a housing, a strain sensor, a three-axis acceleration sensor, a vibration generator and a controller. The housing has an average shape and size of rocks. The strain sensor detects a stress acting in positive and negative directions of each axis with respect to three-dimensional coordinates using the center of the housing as the origin. The three-axis acceleration sensor detects acceleration acting in each axis of the three-dimensional coordinates. The vibration generator produces vibration in a specific direction with respect to the three-dimensional coordinates. The controller converts respective detected values of the strain sensor and the three-axis acceleration sensor into vibration pulses of specific patterns and outputting the vibration pulses to the vibration generator.

Abstract: Electromagnetic field transmissions between a sensor unit mounted on the inside surface of a tire and a sensor control unit mounted on the vehicle body are attenuated by the wall surface of a tire disposed between the units, and sensitivity is reduced. A booster antenna (18) is embedded in the tire wall surface between the sensor unit (6) and the sensor control unit (10). The booster antenna (18) is a coil antenna, and is configured so that the resonance frequency, which corresponds to the impedance and capacitance component of the booster antenna coil, corresponds to the frequency f0 of the transmission electromagnetic field of the sensor control unit (10). The booster antenna (18) is disposed in a position in which a magnetic coupling is formed with the coil antenna of the sensor unit (6), and transmissions via the electromagnetic field between the sensor unit (6) and the sensor control unit (10) are carried out through the booster antenna (18).

Abstract: The position of the rotation of a tire complicates the establishing of a wireless connection between a sensor unit attached to the tire and a sensor control unit attached to a vehicle body. A reflection plate is attached to an inner surface of a wheel housing at a position different from that of a sensor control unit. A transmission electromagnetic field from the sensor control unit is reflected by the metal reflection plate and transmitted to a sensor unit rotated to a position to which the field does not readily reach directly from the sensor control unit. The sensor unit varies an impedance of a coil antenna in accordance with transmission data, and generates a variation in the transmission electromagnetic field. The variation is detected via the reflection plate as a variation in a transmission load of the sensor control unit, and the transmission data from the sensor unit is detected in the sensor control unit.

Abstract: The present invention provides a battery-free electronic key used in motorcycles and improves security. A communication circuit (44) is actuated when an electronic key is inserted into a keyhole. An electromotive force generated in a coil L2 is rectified by a power circuit (74) and supplied to the components of an electronic key-side circuit (40) as a source of power, in accordance with the variations of an electromagnetic field having a frequency of f0 generated by the communication circuit (44). The electronic key-side circuit (40) reads identification information from a storage unit (72), and the information is converted to ternary value data in a binary value/ternary value conversion circuit (70). Transistors Tr1 and Tr2 are switched on and off in accordance with the bit values of 2-bit data that expresses ternary value data, which generates three-stage variations in the electromagnetic field between coils L1 and L2.

Abstract: Electromagnetic field transmissions between a sensor unit mounted on the inside surface of a tire and a sensor control unit mounted on the vehicle body are attenuated by the wall surface of a tire disposed between the units, and sensitivity is reduced. A booster antenna (18) is embedded in the tire wall surface between the sensor unit (6) and the sensor control unit (10). The booster antenna (18) is a coil antenna, and is configured so that the resonance frequency, which corresponds to the impedance and capacitance component of the booster antenna coil, corresponds to the frequency f0 of the transmission electromagnetic field of the sensor control unit (10). The booster antenna (18) is disposed in a position in which a magnetic coupling is formed with the coil antenna of the sensor unit (6), and transmissions via the electromagnetic field between the sensor unit (6) and the sensor control unit (10) are carried out through the booster antenna (18).

Abstract: The position of the rotation of a tire complicates the establishing of a wireless connection between a sensor unit attached to the tire and a sensor control unit attached to a vehicle body. A reflection plate (20) is attached to an inner surface of a wheel housing (16) at a position different from that of a sensor control unit (10). A transmission electromagnetic field from the sensor control unit (10) is reflected by the metal reflection plate (20) and transmitted to a sensor unit (6) rotated to a position to which the field does not readily reach directly from the sensor control unit (10). The sensor unit (6) varies an impedance of a coil antenna in accordance with transmission data, and generates a variation in the transmission electromagnetic field. The variation is detected via the reflection plate (20) as a variation in a transmission load of the sensor control unit (10), and the transmission data from the sensor unit (6) is detected in the sensor control unit (10).

Abstract: A tire inflation pressure determining system is provided in which measurement results are transmitted to the exterior without providing a high precision oscillation circuit to a tire-mounted air pressure determining system. An LC resonance circuit is composed of a coil Ls and an inflation pressure sensor in which the electric capacitance varies in accordance with tire air pressure. The fluctuations of the electromagnetic field having a frequency f0 generated by a sensor control unit are sensed in a coil L2, a clock is generated based on the sensed fluctuations, the clock is inputted to a coil Le that is transformer coupled to the coil Ls, and the LC resonance circuit is excited.

Abstract: A tire inflation pressure determining system is provided in which measurement results are transmitted to the exterior without providing a high precision oscillation circuit to a tire-mounted air pressure determining system. An LC resonance circuit is composed of a coil Ls and an inflation pressure sensor in which the electric capacitance varies in accordance with tire air pressure. The fluctuations of the electromagnetic field having a frequency f0 generated by a sensor control unit are sensed in a coil L2, a clock is generated based on the sensed fluctuations, the clock is inputted to a coil Le that is transformer coupled to the coil Ls, and the LC resonance circuit is excited.

Abstract: A method of estimating an eccentric position of an acceleration sensor for a double turntable-type acceleration generating apparatus includes the steps of mounting the acceleration sensor on an auxiliary rotating body; rotating the auxiliary rotating body at a constant frequency with a main rotating body held at a standstill; measuring an output signal from the acceleration sensor; determining an amount of eccentricity in an X-axis direction of the acceleration sensor from the frequency of the auxiliary rotating body and the output signal; and determining an amount of eccentricity in a Y-axis direction by using tangential acceleration generated by the rotation of the auxiliary rotating body in a state in which the amount of eccentricity in the X-direction is set to substantially zero.

Abstract: An eccentric error corrector for a rotary-type acceleration generating apparatus. The eccentric error corrector includes a large-diameter turntable and a small-diameter turntable. The large-diameter turntable is rotated by a first servo motor. The small-diameter turntable is mounted on the outer periphery portion of the large-diameter turntable and rotatable by a second servo motor, in which an acceleration sensor is attachable to the small-diameter turntable. The eccentric error corrector includes a DC-component remover removing only the DC component from an output signal of the acceleration sensor attached on the small-diameter turntable.

Abstract: To improve a response rate and an impact detection precision of an auxiliary acceleration sensor device for an air bag system, an auxiliary acceleration sensor device includes a longitudinal G sensor for sensing a longitudinal acceleration G of a vehicle, and lateral G sensor for sensing a lateral acceleration G of the vehicle. The longitudinal G sensor includes a constant current source circuit, a detector portion for outputting an electrical signal representative of a longitudinal acceleration G, and an amplifier portion for amplifying the signal received from the detecting portion. The comparator includes comparing elements that compare the voltage values corresponding to longitudinal threshold values Tf1 to Tf4 of the longitudinal acceleration G with an output signal of the amplifier portion.

Abstract: The invention provides a semiconductor acceleration sensor which is small in size, light in weight, simple in manufacture, low in manufacturing cost, and high in accuracy, and which, with a switch-on time set to a predetermined value, is stable in operation. In a semiconductor acceleration sensor in which a central board 1 having a central contact section 11, and outside boards 2 at least one of which has an outside contact section 21 are stacked; the central board 1 has a weight 12 near the central contact section 11, and the outside board 2 having the outside contact section 21 has a weight confronting section 11 which confronts with the weight 12, for squeezed damping effect.

Abstract: A turntable acceleration generating apparatus includes a first servo motor, a large-diameter turntable rotated by the first servo motor, and a small-diameter turntable being mounted on the large-diameter turntable at a position offset from the central axis of the large-diameter turntable such that the small-diameter turntable is rotated by a rotary shaft. Furthermore, the turntable acceleration generating apparatus includes a signal line for deriving signals from an acceleration sensor located on one of the sides of the large-diameter turntable, and a control signal line for applying control signal to a second servo motor located on the other side of the large-diameter turntable, wherein the large-diameter turntable is grounded such that the large-diameter turntable prevents noise leakage from the control signal line to the signal line.

Abstract: A semiconductor acceleration sensor including a central board having a movable electrode section, an outside board having a stationary electrode section, and a sealing insulating section for joining the central board and the outside board which are laminated on each other, wherein the sealing insulating section has a conductive layer, and the conductive layer is a sealing member or an anodic bonding electrode.

Abstract: An acceleration sensor includes a first substrate, a second substrate and a third substrate. The second substrate has a through-hole, a first contact formed on an inner surface of the through-hole, and a first bonding pad connected to the first contact. An electrically conductive ball is accommodated in the through-hole. The third substrate has a recess, a second contact formed in the recess contacting the bottom of the electrically conductive ball, and a second bonding pad connected to the second contact.