A LOW-COST MINIATURE VOID SENSOR

MECHANICAL G-SWITCHES ARE PRESENTLY AVAILABLE THAT SENSE WHEN THE ACCELERATION EXCEEDS A SPECIFIED VALUE. CONTACT RESISTANCE IS A PROBLEM EVEN WITH NEWLY FABRICATED MECHANICAL G-SWITCHES. MECHANICAL CONTACTS ARE ALSO SUBJECT TO SWITCH BOUNCE AND DAMAGE DURING THE INITIAL SHOCK OF IMPACT. SILICON DESIGNS HAS DEVELOPED A PROCESS FOR BUILDING MICROMECHANICAL SENSE ELEMENTS ON THE SURFACE OF A SILICON WAFER THAT CONTAINS SENSING CIRCUITRY FABRICATED WITH STANDARD INTEGRATED CIRCUIT (IC) TECHNOLOGY. THIS ALLOWS THE LARGE QUANTITY PRODUCTION OF ACCELEROMETERS WITH SOPHISTICATED ACCOMPANYING ELECTRONICS AT A LOW COST. EACH TRANSDUCER CHIP IS THEN PACKAGED MUCH LIKE STANDARD ICS. SENSE ELEMENTS CAN BE DESIGNED FOR A WIDE RANGE OF ACCELERATIONS. HIGH RELIABILITY, LOW-COST G-SWITCHES CAN BE BUILT WITH THIS TECHNOLOGY THAT DO NOT RELY ON METAL-TO-METAL CONTACTS. IN ADDITION, EACH SENSOR CAN BE INDIVIDUALLY CALIBRATED AFTER FABRICATION, RESULTING IN HIGH PRODUCTION YIELDS. WE ANTICIPATE THAT ELECTRONIC G-SWITCHES CAN BE MANUFACTURED USING THIS TECHNOLOGY IN HIGH VOLUMES FOR LESS THAN $5 EACH, POSSIBLY IN THE $2-3 RANGE, DEPENDING ON THE TEST REQUIREMENTS.