Patent ID: 7012244

Claim:
An optical turnstile apparatus for monitoring or controlling the flow of persons through a gangway, comprising: a radiation transmitter optically connected to an edge of a first planar optical guide element; a radiation receiver optically connected to an edge of a second planar optical guide element; wherein, the first and second planar optical guide elements are displaced respectively from each other, so as to delimit a gangway through which access may be obtained, the gangway being of suitable size for a person to walk through it; and wherein, an edge of the first planar optical guide element distal from the radiation transmitter is adapted to redirect radiation towards an edge of the second planar optical guide element distal from the radiation receiver, which in turn is adapted to redirect radiation towards the radiation receiver, thereby enabling a transmitted beam of radiation to traverse the intervening gangway and terminate at the radiation receiver; the optical turnstile further comprising means for detecting a break in the transmitted beam.