An optical transducer includes a housing containing a light source and a light
detector laterally spaced from the light source; and a deformable membrane mounted
over the light source and light detector such that an inner surface of the membrane
reflects light from the light source to the light detector to produce, from the
light detector, an output electrical signal modulated in accordance with the deformations
of the membrane. The inner surface of the membrane has a small central region of
high light reflectivity to maximize the output electrical signal produced by the
deformations of the membrane, and a large outer region of lower light reflectivity
to minimize noise in the output electrical signal produced by multi-reflection
of light from the light source to the light detector. The membrane is preferably
formed in its outer region with circular corrugations coaxial with each other and
with the central region of high light reflectivity to increase the deformability
of the central region.
