| 摘要 |
<p>If a pulse encoder having a plurality of absolute-type slits (24, 26, 28, 30) and a plurality of increment-type slit groups (14, 16, 18, 20) has a structure wherein the shape of each increment-type slit group is rectangular, it is impossible to irradiate both of these groups and the absolute-type slits with one light-emitting element (46). To solve this problem in this invention, the increment-type slit groups are formed each in a sectorial shape and are radially arranged about the optical axis (13) of the light-emitting element (46). It becomes thus possible to arrange the absolute-type slits (24, 26, 28, 30) in the remainder of a region (12) irradiated with the one light-emitting element (46) and, hence, to provide a pulse encoder which is compact at a low cost.</p> |
