| 摘要 |
PURPOSE:To simplify the constitution of an invasion monitor apparatus by reducing the number of invasion sensors and to reduce the number of anchoring processes, by providing a refraction means between a light emitter and a light receiver. CONSTITUTION:Between the light emitter T1 of the cylinder 1 at the corner part A of an invasion area F and the light receiver R1 of the cylinder 3 at the other corner part C, a reflective mirror M1 for refracting laser beam is further provided so as to be arranged to the cylinder 2 at the other corner part B. Light transmitters and light receivers T2 and R2, T3 and R3, T4 and R4 at the corner parts A-D of the area F are also similarly provided and it is unnecessary to provide the light transmitters and light receivers of invasion sensors at every corner parts. Therefore, the number of invasion sensors are reduced and the constitution of the invasion monitor apparatus becomes simple and the number of anchoring processes of said apparatus are reduced. |
