Glazing unit alarm system

摘要

A glazing unit alarm system comprising a glazing unit having at least one glazing panel and provided with spaced apart first and second faces and electric alarm means. The electric alarm means comprises a light transmitting electrically conductive coating on the first face and conducting breakable means on the second face. The alarm means are connected in series with the electrically conductive coating and the conducting means to respond to changes in resistance occasioned by a breakage or an attempted breakage of the glazing unit.