| 摘要 |
An analog position indicating optical encoder is provided including: an element (1) with a band (2) having a transparency which substantially is complete with respect to two wavelengths (11 and 12) but varies as a function of the angular or linear distance for a third wavelength (13) at wavelength which is between the above-said two wavelengths (11 and 12); light emitting means (31,32,33) emitting three light beams (71,72,73) at the above said wavelengths (11,12,13); a first optical coupler (5,6) mixing the beams (71,72,73); optical bidirectional transmission means of the optical fiber type (B); a second optical coupler (18,19) dividing into three beams (201,202,20'3) the light leaving the means (B) after being reflected by the optical element (13) and after passing through the band (2); three readers (231,232,233) responsive to the wavelength (11,12, and 13); and an electronic unit (25) connected to the optical readers (231,232), and determining the ratio between the mean readers reading the wavelengths 11 and 12 corresponding to the wavelength 13 the responses of 231 and 232 and the response of 233.
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