Patent ID: 6399941
Filing Date: 2002-06-04
Classification: G01C

Abstract:
An inclination angle sensor comprising:a slit plate supported rotatably about a rotary shaft, and having a zero detection slit and a plurality of equally spaced angle detection slits along a circumferential direction thereof; a weight attached to said slit plate; three pairs of photo-interrupters, each pair comprising a light-emitting element and a light-receiving element, fixed with respect to a bearing so that said light-emitting element and said light-receiving element confront each other with said slit plate therebetween; and an eddy current damping means fixed with respect to said bearing in a position for generating electromagnetic damping with said weight by an eddy current, first and second pairs of said three pairs of photo-interrupters are positioned so that light is transmitted or shielded by said angle detection slits in said slit plate, and are shifted from each other by 90Â° in phase of an emerging cycle of said angle detection slits in a rotational direction of said slit plate, and a third pair of said three pairs of photo-interrupters is positioned so that light is transmitted through said zero detection slit when said slit plate is in a position of 0Â°.