METHOD AND APPARATUS FOR SENSING PROXIMITY OR POSITION OF AN OBJECT USING NEAR-FIELD OR MAGNETIC EFFECTS

摘要

A method and apparatus for sensing proximity of an object using near-field effects or magnetic effects. The sensor chips are designed to accommodate numerous sensing elements. In the electromagnetic sensor, radio frequency energy is fed to an antenna. The antenna radiates this radio frequency energy to charge the surface of an object. When the position of the object changes, the impedance of the antenna due to near-field effects changes. This impedance change is detected to provide an indication of the object's movement. In the magnetic sensor, the sensing element is placed at a right angle to the sensor electronics to provide a smaller surface area across the diameter of the sensor. The magnet that charges the object to be detected is manufactured as a part of the sensor encapsulant. The sensing device may be packaged to be inserted into a wall to provide a sensor having a leakfree seal.