Patent ID: 6973731
Filing Date: 2005-12-13
Classification: G01D

Abstract:
1. An encoder comprising: a fixed member; a rotary member; and a click mechanism for stabilizing the rotary member at each rotation for a predetermined click angle, one of the fixed member and the rotary member being provided with an electrode having A-channel, B-channel and C-channel patterns, the other of the fixed member and the rotary member being provided with contacts which are to be opposed to the electrode so 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, wherein 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) the state between the A-channel and the C-channel switches between the first state and the second state at each rotation of the rotary member for the click angle, (b) as the rotary member is rotated for the click angle in one direction from a reference phase where the state between the A-channel and the C-channel is in the first state while the rotary member is stabilized by the click mechanism, the state between the B-channel and the C-channel remains unchanged from the first or second state, and (c) as the rotary member is rotated for the click angle in an opposite direction from the reference phase, the state between the B-channel and the C-channel switches twice between the first state and the second state.