A new method of position detection using an optical scanning angle sensor

A new position detecting method, which uses a 2-D angle grid and a 2-D angle sensor, is proposed. The angle grid has a 2-D sinusoidal angular pattern on the surface. The relative displacements between the angle grid and the angle sensor in the X- and Y-directtons can be detected from the output of the angle sensor. Because of the angle independency in the X- and Y- directions, it is possible to detect the X- and Y-directional positions from the 2-D angle sensor outputs. Furthermore, use of an optical scanning angle sensor, which scans a beam spot on the angle grid, can reduce the effect of the form error of the angle grid. Rolling and pitching can also be detected by using this method. In this paper, a scanning 2-D angle sensor is designed and manufactured. Experimental results of position detection are reported.