| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a linear encoder having high light-receiving sensitivity for detecting surely light output from a light source, even when using a high-output light source. Ž<P>SOLUTION: In a linear gage 1, lights having first and second wavelengths having mutually different wavelengths are output from light sources 20 (a first LED 20a, a second LED 20b), and the lights output from the light sources are collimated by a lens array 30 (collimator lens), condensed by a fresnel lens 40, and introduced into one end 50a of an optical fiber 50. Then, light output from the other end 50b of the optical fiber 50 is separated into lights having the first and second wavelengths by a dichroic filter 70, transmitted through a scale 100 (a first track 100a, a second track 100b), and received by a first light receiving element 140 and a second light receiving element 150 wherein each range of receivable wavelengths is not overlapped. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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