Imaging rotation angle absolute encoder
First Claim
Patent Images
1. An absolute encoder, comprising:
- a light source;
an encoded code rod, wherein the rod has an outer surface encoded with code marks for determining angular position, wherein the code marks comprise a fine code line pattern and a plurality of staggered non-overlapping approximately equal length coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod; and
a light detector configured to detect light reflected from or transmitted through the code marks.
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Accused Products
Abstract
An angle absolute encoder comprises an encoded code rod that has code marks, such as pairs of fine code lines and coarse code lines. Light is reflected from or transmitted through the code marks and detected by a light detector to determine absolute angle position.
92 Citations
33 Claims
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1. An absolute encoder, comprising:
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a light source; an encoded code rod, wherein the rod has an outer surface encoded with code marks for determining angular position, wherein the code marks comprise a fine code line pattern and a plurality of staggered non-overlapping approximately equal length coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod; and a light detector configured to detect light reflected from or transmitted through the code marks. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of determining an absolute angle position of an object, the method comprising:
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providing an encoded code rod; rotating the code rod; and detecting code marks on the code rod to determine absolute angle position, wherein the code marks comprise a fine code line pattern and a plurality of non-overlapping coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod and having a total length approximately equal to the circumference of the code rod, wherein the detecting comprises determining which one of the coarse code lines is in view of a sensor and measuring a corresponding fine code line to determine where within the coarse code line the code has rotated. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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- 21. A code rod for an absolute encoder, the code rod comprising code marks located along the circumference and length of the rod, wherein the code marks are used to determine an absolute angle position and comprise a fine code line pattern and a plurality of non-overlapping coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod and each fine code line corresponds to a coarse code line to form a code line pair, and wherein the coarse code lines are staggered and approximately of equal length.
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27. A code rod for an absolute encoder, comprising:
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a cylindrical rod; code marks located along the circumference and length of the rod, the code marks comprising; a fine code line pattern; and a plurality of staggered non-overlapping approximately equal length coarse code line segments around the circumference of the rod and between the fine code line pattern and a first end of the rod, wherein the coarse code lines are oriented approximately perpendicular to the axis of rotation of the code rod; and a reference line along the circumference of the rod and between the fine code line pattern and a second end of the rod. - View Dependent Claims (28, 29, 30)
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31. A method of determining an absolute angle position of an object, the method comprising:
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providing an encoded code rod; rotating the code rod; and detecting code marks on the code rod to determine absolute angle position, wherein the code marks comprise a fine code line pattern and a plurality of non-overlapping coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod and staggered and approximately of equal length, wherein the detecting comprises determining which one of the coarse code lines is in view of a sensor and measuring a corresponding fine code line to determine where within the coarse code line the code has rotated.
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32. A code rod for an absolute encoder, the code rod comprising code marks located along the circumference and length of the rod, wherein the code marks are used to determine an absolute angle position and comprise a fine code line pattern and a plurality of non-overlapping approximately equal length coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod and each fine code line corresponds to a coarse code line to form a code line pair, and wherein the total length of the coarse code lines is approximately equal to the circumference of the code rod.
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33. A code rod for an absolute encoder, the code rod comprising code marks located along the circumference and length of the rod, wherein the code marks are used to determine an absolute angle position and comprise a fine code line pattern and a plurality of non-overlapping coarse code lines around the circumference of the code rod, with the coarse code lines oriented approximately perpendicular to the axis of rotation of the code rod and each fine code line corresponds to a coarse code line to form a code line pair, and wherein each code line pair comprises non-parallel fine and coarse code lines.
Specification