| 摘要 |
PCT No. PCT/SE90/00334 Sec. 371 Date Nov. 19, 1991 Sec. 102(e) Date Nov. 19, 1991 PCT Filed May 18, 1990 PCT Pub. No. WO90/14581 PCT Pub. Date Nov. 29, 1990.An apparatus for emitting and receiving light comprises an emitter, which consists of a light source (5) and a concave mirror (7), and a receiver which receives light from the emitter and which is connected to analyzing equipment (3). Furthermore, the receiver comprises a concave mirror (9) which is disposed behind the mirror (7) of the emitter and whose diameter is larger than that of the mirror (7) of the emitter and whose focus is located in front of the light source (5). In the focus of the mirror (9) is positioned one end of an optical fibre (19) for transmitting the received light to the analyzing equipment (3). Moreover, the apparatus comprises a retroreflector unit (17) for reflecting the light from the emitter to the receiver, and a movable shielding element (11) which is provided between the light source (5) and the optical fibre (19) and which prevents, in a first position, the light from the light source from reaching the optical fibre directly, and lets through, in a second position, the light from the light source directly to the optical fibre. |
