A passenger detection system comprises an antenna electrode which is provided to the dashboard of a car, an oscillation circuit for generating a high frequency low voltage oscillation signal in order to generate a weak alternating electric field around the antenna electrode, a current detection section for detecting a transmission current which passes between the oscillation circuit and the antenna electrode depending on the weak alternating electric field which is generated around the antenna electrode, a phase difference detection section for detecting the phase difference between the oscillation signal supplied from the oscillation circuit and an output signal which is supplied to the antenna electrode, and a control circuit for judging the presence or absence of a passenger seated on the seat based on the detected phase difference and judging the distance between the passenger and the dashboard based on the detected transmission current. The passenger detection system is connected with an air bag unit, and the air bag unit is set at a ‘no deployment mode’ if it is judged that no passenger is seated on the seat or the distance between the passenger and the dashboard is less than a minimum allowable distance, thereby the passenger who is close to the dashboard is protected from secondary injury due to strong deployment of the air bag.

Passenger detection system

A vehicle passenger sensing system and method in which the presence and position of a passenger is determined by transmitting an electric field (410) from a first electrode (30) and measuring currents induced by the electric field (420, 430) in a plurality of receiver electrodes (40, 50). The induced currents at the various receiver electrodes (40, 50) are then compared to determine the presence of an adult size passenger, to distinguish between a child in a front-facing child safety seat and a child in a rear-facing infant seat, and to detect when a passenger is out of position. A switching circuit (620) is provided to selectively transmit the electric field from each of the plurality of electrodes (511, 512, 516/517, 521, 522).

Vehicle passenger sensing system and method

A capacity type proximity sensor comprised of a capacitance type sensor, a capacitance type reference, and two independent and mutually opposing driven shields respectively adjacent the sensor and reference and which are coupled in an electrical bridge circuit configuration and driven by a single frequency crystal controlled oscillator. The bridge circuit additionally includes a pair of fixed electrical impedance elements which form adjacent arms of the bridge and which comprise either a pair of precision resistances or capacitors. Detection of bridge unbalance provides an indication of the mutual proximity between an object and the sensor. Drift compensation is also utilized to improve performance and thus increase sensor range and sensitivity.

Double-driven shield capacitive type proximity sensor

Apparatus and methods are disclosed for measuring the properties of a material by employing a driven electrode (4), a sensing electrode (6), and a shunting electrode (8). The shunting electrodes are disposed in proximity to the driven and sensing electrodes and function to increase the sensitivity of electrical measurements made between the driven and sensing electrodes by influencing the coupling of the imposed electric field to the sensing electrode to a degree related to the properties of the material under test.

Apparatus and methods for measuring the dielectric and geometric properties of materials

A quasi-electrostatic sensing system surrounds an electrically conductive mass with an electric field, the magnitude of which is sensed at one or more locations to resolve a property of interest concerning the mass. The object intercepts a part of the electric field extending between the AC-coupled "sending" electrode and the other "receiving" electrodes, the amount of the field intercepted depending on the size and orientation of the sensed mass, whether or not the mass provides a grounding path, and the geometry of the distributed electrodes. Because the response of the field to an object is a complex nonlinear function, adding electrodes can always distinguish among more cases. In other words, each electrode represents an independent weighting of the mass within the field; adding an electrode provides information regarding that mass that is not redundant to the information provided by the other electrodes. A "forward model" that relates the behavior of the system to variations in the property to be measured is established, and "inversion" of this model facilitates recovery of the property based on system behavior. The invention is amenable to a wide variety of usages including the detection of user positions and gestures as a means of conveying two- and/or three-dimensional information to, for example, computers, appliances, televisions, furniture, etc.; provision of data input or instructional commands to a device; or sensing of proximity to a reference object for security purposes, to warn of danger, or to conserve energy by withholding power until a potential user approaches the object.

Method for three-dimensional positions, orientation and mass distribution

Apparatus for detecting the amount or presence of material in a detection zone comprising a first electrode, input signal means for supplying an electric input signal to the first electrode; a second, smaller electrode parallel to the first electrode; the detection zone being located between the first and second electrodes; a third electrode which is larger than the second electrode and substantially surrounds the second electrode in a plane parallel to the first electrode, and receiving means for detecting signals on the second electrode, the signal on the second electrode being responsive to material in the zone. The second and third electrodes are not electrically connected but are maintained at near the same electric potential whereby the electric field between the first and second electrodes is, in use, substantially linear and fringing fields, if any, occur only between first and third electrodes at their outer edges.

Richard Edward Junger

Papers

Capacitive material presence detecting apparatus