Patent ID: 7385685
Filing Date: 2008-06-10
Classification: G01C

Abstract:
1. A position detecting device, comprising: a liquid having a free surface; a light source configured to irradiate a light flux toward the free surface of the liquid; a dark field pattern provided between the liquid and the light source and including patterns having widths different from each other in both an X-direction and a Y-direction, and configured to form the patterns of the light flux irradiated by the light source; a light-receiving sensor configured to detect the patterns of the light flux reflected by the free surface of the liquid; and an arithmetic unit configured to calculate positions of the patterns from results of detection of the light-receiving sensor, add the results of the detection of the light-receiving sensor in the X-direction and the Y-direction of the light-receiving sensor, and calculate the positions of the patterns from an output obtained by adding the results of the detection in the X-direction and the Y-direction.