Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1991-06-11
1993-12-28
McGraw, Vincent P.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
G01D 534
Patent
active
052742296
ABSTRACT:
An optical shaft angle encoder has a circumferentially extending data track having alternating windows and opaque spaces or spokes between the windows. Each window and space between windows has substantially the same width along the track. An array of photodetectors is provided adjacent to the data track, with each photodetector having substantially the same width as a space or window. An LED illuminates the photodetectors through the windows. The lengths of each window transverse to the data track, and hence the area of each window, is selected from a limited set which preferably has lengths varying by powers of 2. The areas of successive windows along the track are in a predetermined sequence which does not repeat around the track. The photo current due to illuminating the photodetectors in the array provides a unique indication of the angular position of the code wheel. To assure a reading of the angular position at essentially all times, including immediately upon startup of the encoder, there are interleaved arrays of odd and even numbered photodetectors. Half-width selection photodetectors select one of the adjacent odd numbered photodetector currents to be added to each even numbered photodetector current so that the entire illumination through each window over the array is measured.
REFERENCES:
patent: 4421980 (1983-12-01), Kuhne
patent: 4691101 (1987-09-01), Leonard
Hantis K. P.
Hewlett--Packard Company
McGraw Vincent P.
LandOfFree
Absolute position 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 Absolute position encoder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absolute position encoder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1544845