| 摘要 |
<p>PURPOSE:To enable measurement of length with the same accuracy as that for laser interference length measurement with removed side peak, by detecting a beam of light of each frequency band with a plurality of different high-speed detectors and filtering it to make a function S(nu) a peakless one. CONSTITUTION:A product of a frequency concentration distribution function of a light source and a frequency sensitivity characteristic function of a detector is assumed to be S(nu). By using a complementary dichroic mirrors of perfect reflection and transmission as wave-branching elememts 8-10, the beam of light, under prevention of generation of a discontinuous point, is irradiated into detectors 12-14 through filters 20-22 featuring a transmission spectroscopic characteristic of making the function f(nu) peakless. By employment of composition of output of the detector, that is to say, composition of output combining a stepless resistance 18 in a boundary of a responsible band range, generation of a side peak is prevented and detection of a high-speed interference zero fringe, namely accurate determination of a fixed poit for length measurement becomes available.</p> |
