Patent ID: 8193483
Filing Date: 2012-06-05
Classification: G01D,G02B

Abstract:
1. A triple dome lens reflective optical encoder, comprising: a printed circuit board or lead frame substrate having a top surface with opposing first and second sides defined by a first axis disposed therebetween, and opposing third and fourth sides defined by a second axis disposed therebetween, the first axis being substantially perpendicular to the second axis; a light emitter mounted on or attached to the first side and configured to emit light therefrom, the light emitter being covered by a first dome lens formed thereover and in direct contact therewith such that no air gap is located between the light emitter and the first dome lens, the first lens being transfer molded directly over the light emitter; an index channel detector mounted on or attached to a first area defined by a first overlap of the second and third sides, the index channel detector being covered by a second dome lens formed thereover and in direct contact therewith such that no air gap is located between the index channel detector and the second dome lens, the second lens being transfer molded directly over the index channel detector; at least one data channel detector mounted on or attached to a second area defined by a second overlap of the second and fourth sides, the data channel detector being covered by a third some lens formed thereover and in direct contact therewith such that no air gap is located between the data channel detector and the second dome lens, the data channel detector comprising at least four light detectors corresponding to A, B, A and B data channels, respectively, the third lens being transfer molded directly over the data channel detector; an optically opaque light barrier, air gap trench or portion disposed between the light emitter and the first side and the second and third dome lenses on the second side, the light barrier, air gap trench or portion being configured to prevent or inhibit direct light rays emitted by the light emitter from impinging directly upon the index channel detector or the data channel detector; wherein the first dome lens is configured to permit light emitted from the light source to be refracted through portions thereof for reflection from a first code scale or code wheel comprising data strips as well as for reflection from a second index scale or index wheel, the first code wheel or code strip and the index wheel or index strip being configured to travel along respective parallel third and fourth axes, the index scale or index wheel being located operably in respect of the first and second dome lenses such that at least a portion of the light reflected from the index strip or index wheel is directed towards the second dome lens and refracted through portions thereof for detection by the index channel detector, the code scale or code wheel being located operably in respect of the first and third dome lenses such that at least a portion of the light reflected from the code strip or code wheel is directed towards the third dome lens and refracted through portions thereof for detection by the data channel detector, the optical encoder further being configured to provide a first output signal corresponding to the index channel and second output signals corresponding to the A and B data channels, the first output signal having a duration less than that of the second output signals.