English: The optical sensor array extracted from the laser optical pickup of a CD player. The three dark rectangles are photosensors which read the data from the disk, senses beam focus and senses beam centering on the disc's optical track. Two tracking photosensors, each adjacent to the signal photosensor on the center, helps the optical servo system to keep the laser beam on track.
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.