| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement information detector capable of accurately detecting position and angle information suitable for industrial measuring machines. SOLUTION: A diffraction grating scale for relatively moving coherent light flux from a source means is lit to generate two different orders of diffracted lights, and two diffracted lights are diffracted and deflected by a diffraction grating formed by arranging arc or annular curves in a lattice shape with non-equal pitches. The diffraction grating scale is lit again to diffract again, both diffracted lights are overlapped with each other to interfere with each other, and the coherent light is led to a light receiving element to detect periodic signals accompanying the relative movement of the diffraction grating scale. COPYRIGHT: (C)2004,JPO
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