摘要 |
A position control system employing a movable detector means which communicates energy to and from a pattern of passive, position-related indicia or marks on a surface. In the preferred embodiment the movable detector means includes a light source and a four-quadrant detector, with the surface having a high contrast checkerboard square pattern. The four-quadrant detector will report different states as the detector means is moved across different squares. The states are decoded in a lookup table and electrical signals are generated for controlling X and Y registers of a cursor control or the like.
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