| 摘要 |
<p>A directional optical microphone (2) includes a housing (4) having an open wall portion closed by a membrane (22) attached thereto. The membrane (22) has an outer surface, and an inner surface facing the inside of the housing (4). A first light waveguide (12) is accommodated within the housing (4), this waveguide having an output end portion (20) for transmitting light towards the inner surface of the membrane (22). A second light waveguide (14) has an input end portion (20') for receiving light reflected from the inner surface of the membrane (22). The output and input end portions (20 and 20') are positioned in close proximity to, and in optical isolation from, each other. At least one aperture (6) is made in a wall of the housing (4), said aperture having a cross-sectional area of not less than 1 mm<2> , and being provided for admitting sound waves into the housing to impinge on the inner surface of the membrane (22). <IMAGE></p> |
