| 摘要 |
PURPOSE:To improve resolving power and S/N ratio and thereby perform highly precise detection of a position by performing the detection of the position by using a pattern based on two-valued random numbers or a pattern based on M series or pluralistic M series which are excellent in autocorrelation property. CONSTITUTION:A pair of scales 2 and 3 having patterns prepared, for instance, on the basis of two-valued random numbers of thirty-one cycles (01001010011010 10101110100111010) wherein 1 is assigned to the pass of light and 0 to the interception thereof and constituted by a part 7 passing light and a part 8 intercepting light are used, and the scale 2 is fixed, while the scale 3 is set on a moving body. And the light from a light source 1 passing through windows 7 moving in parallel to each other is detected through the random patterns on the scales 2 and 3 by a detector 4. By detecting the position of coincidence of both random patterns, the coincidence of positions of bodies moving in parallel relatively is detected. |
