Anti-thief security sensor assembly using the opening of the projector cover for beam adjustment

摘要

To provide an anti-thief security sensor assembly wherein an optical axis adjustment of a beam projector can be accurately achieved merely by physically opening a cover of a beam projecting unit while a cover of a beam receiving unit is not opened physically, the anti-thief security sensor assembly includes a beam projecting unit (1) for emitting an infrared beam IR and having a projector cover (21A) mounted on a projector base (20A) so as to cover and protect a sensor circuit. This beam projecting unit (1) includes an opening detecting switch (7) for detecting the physical opening of the projector cover (21A) and a transmission request generating circuit (8) operable in response to the detection by the opening detecting switch (7) to output a received beam level transmission request signal B to the beam receiving unit (2). The beam receiving unit (2) for receiving the infrared beam IR from the beam projecting unit 1 includes a level output circuit (52) operable in response to receipt of the received beam level transmission request signal B to transmit to the beam projecting unit (1) a level display signal C indicative of the amount of the infrared beam received by the beam receiving unit (2).