Patent ID: 6946979
Filing Date: 2005-09-20
Classification: G01D,H03M

Abstract:
1. An encoder comprising: a fixed member; a rotary member; and a click mechanism for stabilizing the rotary member at predetermined click angles, wherein one of the fixed member and the rotary member has an electrode with a predetermined pattern, the other of the fixed member and the rotary member has A-channel, B-channel and C-channel contacts opposing the electrode such that as the rotary member is rotated, a state between the A-channel and the C-channel and a state between the B-channel and the C-channel switch between a first state and a second state according to contact/noncontact between the respective contacts and the electrode, one of the first state and the second state is a conductive state, and the other of the first state and the second state is a nonconductive state, wherein (a) if a phase where the state between the A-channel and the C-channel is in the first state and the state between the B-channel and the C-channel is in the second state while the rotary member is stabilized by the click mechanism, is taken as a reference phase, (b) when the rotary member is stabilized after rotation over one click angle in one direction from the reference phase, the state between the A-channel and the C-channel is in the second state and the state between the B-channel and the C-channel is in the first state, and (c) when the rotary member is stabilized after rotation for the click angle in an opposite direction from the reference phase, both the state between the A-channel and the C-channel and the state between the B-channel and the C-channel are in the first state.