| 摘要 |
PCT No. PCT/JP97/00742 Sec. 371 Date Nov. 7, 1997 Sec. 102(e) Date Nov. 7, 1997 PCT Filed Mar. 10, 1997 PCT Pub. No. WO97/33186 PCT Pub. Date Sep. 12, 1997A laser beam generated from a laser beam generating means 201 is reflected on a semiconductor mirror galvanometer 102. A region 105 to be inspected is scanned with the reflected laser beam 106. The laser beam 106 passing through the region 105 to be inspected is received by a light receiving device array 130. A pulse train included in an output signal produced from the light receiving device array 130 are monitored by a signal processing circuit 206. If an obstacle intrudes into the region 105 to be inspected and induces a pulse deficiency in the pulse train, the deficiency is detected by use of a pulse deficiency detecting circuit 204. A constitution mentioned above provides an optical barrier apparatus capable of reducing manufacturing costs without endangering a fail-safe property.
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