| US 7,615,737 B2 | ||
| High precision compact rotation angle absolute encoder | ||
| Jonathan M. Saint Clair, Seattle, Wash. (US); Bing Wen, Camarillo, Calif. (US); Jian Ma, Thousand Oaks, Calif. (US); and Mitchell D. Voth, Lake Tapps, Wash. (US) | ||
| Assigned to The Boeing Company, Chicago, Ill. (US) | ||
| Filed on May 08, 2007, as Appl. No. 11/745,693. | ||
| Prior Publication US 2008/0277570 A1, Nov. 13, 2008 | ||
| Int. Cl. G01D 5/34 (2006.01) | ||
| U.S. Cl. 250—231.13 [250/231.18] | 32 Claims |
| 1. An absolute encoder, comprising:
a light source;
an encoded code rod with an axis of rotation, wherein the rod has an outer surface encoded with code marks configured in a
plurality of adjacent segments along the axis of rotation of the rod for determining angular rotation position, wherein a
first one of the segments comprises a straight single diagonal code line offset from the axis of rotation by a first non-zero
angle and a second one of the segments comprises a plurality of straight parallel diagonal code lines offset from the axis
of rotation by a second non-zero angle less than the first non-zero angle; and
a light detector configured to detect light reflected from or transmitted through the code marks;
wherein the light detector is configured to detect a first axial position of a first point of intersection between the single
diagonal code line of the first segment and a first line defined by a first portion of the light detector, and configured
to detect a second axial position of a second point of intersection between one of the plurality of straight parallel diagonal
code lines of the second segment and a second line defined by a second portion of the light detector, wherein the first and
second points of intersection move along the length of the code rod as the rod rotates.
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