Encoder, Dual Head, Diagonal
Sunday, September 03, 2006
The Dual Head Optical Encoder has been designed and developed consisting of a laser, beam-steering optics and an array of photodetectors. The Encoder contains two optical heads at diametrically opposite positions. The optical heads can move perpendicular to the surface of the grooved disk track (maintaining focus) and along the diameter between the heads to track the radial positions of the grooved disk. One of the optical heads components is a lens mounted on a device that can be moved up or down electromagnetically to track the surface of the disk. The lens distorts the reflected light so that variations in the distance from the disk surface give rise to variations of illumination of the individual photodetectors. This information is used to maintain focus. After the Encoder is adjusted for focus and radial position, its automatic alignment features allows for continuous positional correction using the middle groove of the grooved disk as a zero reference.
Source: NASA Tech Briefs, April 1991
Reference: E. Osborne, Goddard Space Flight Center
Industrial Products
posted by JD52 @ 12:48 AM,
