Patent ID: 7012201
Filing Date: 2006-03-14
Classification: G01D,G05G,H01H

Abstract:
1. A rotary encoder comprising: a roller of substantially cylindrical shape having a center hole; a tubular inner shaft inserted in and connected to the center hole, the inner shaft having a slit formed at one end along a direction parallel to the axis thereof; a translucent cylindrical light guide shaft inserted in the inner shaft in a manner that one end is surrounded by the slit, the light guide shaft having: a pair of holders securely holding one end of the light guide shaft, and supporting the roller in a rotatable manner through the inner shaft; a light-detecting device disposed under one end of the light guide shaft; and a light-emitting device disposed under the other end of the light guide shaft, wherein light emitted by the light-emitting device enters the light guide shaft at the first plane, is reflected off the first inclined plane and the second inclined plane, led to an outside of the light guide shaft through the second plane, and detected by the light-detecting device when it passes through the slit.