Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1989-01-09
1990-10-16
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
25023117, 250237G, G01D 534
Patent
active
049637339
ABSTRACT:
An incremental encoder comprises a rotatable disc having an axis of rotation and a plurality of circumferentially arranged slots formed in the disc at equal angular increments. Light source is so positioned on one side of the disc so as to illuminate the slots. A first light sensor is so positioned on the other side of the disc as to receive light from the source means transmitted through the slots. A second light sensor is so positioned on the other side of the disc farther from the axis than the first sensor so as to receive light from the source transmitted through the slots out of phase with the light transmitted to the first sensor. A third light sensor is so positioned on the other side of the disc as to receive light from the source transmitted through the slots for control purposes. The third sensor lies at the intersection of an arc having a center at the first sensor and a radius equal to the distance between the first and second sensors and an arc having a center at the axis of rotation and a radius equal to the distance between the axis of rotation and a point, preferably the midpoint, between the first and second sensors. A slit plate having a light transmitting aperture is disposed between the light source and the disc. Another slit plate having three slits defining first, second and third light receiving apertures is disposed between the disc and the sensors. The spacing between the first and second light receiving apertures is equal to 1/4 the spacing between the slots on the disc times the ratio of the distance between slit plates divided by the distance between the first slit plate and the disc.
REFERENCES:
patent: 4218615 (1980-08-01), Zinn, Jr.
patent: 4556792 (1985-12-01), Kano et al.
patent: 4628200 (1986-12-01), Tinios
Nelms David C.
TRJ & Company
LandOfFree
Incremental encoder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Incremental encoder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Incremental encoder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-851096