Patent ID: 7714718

Claim:
A security assembly, comprising: a first building structure at least partially defining a building opening, said first building structure having a first surface; a movable building structure movable between a closed position in which said movable building structure covers said opening and an open position in which said movable building structure uncovers said opening, said movable building structure having a perimeter with a second surface disposed in opposition to said first surface when said movable building structure is in the closed position; and an optical sensor apparatus including: an electronics module mounted in association with one of said first surface and said second surface, said electronics module having an optical emitter and an optical receiver, said optical emitter being configured to emit a first beam, the first beam diverging from said optical receiver; and a reflector arrangement mounted in association with an other of said first surface and said second surface, said reflector arrangement being configured to provide a plurality of sequential reflections of the first beam to thereby produce a second beam directed at said optical receiver.