Patent ID: 8897111

Claim:
A system for determining a cleanliness of a lens of an optical disc drive, the system comprising: a controller configured to control movement of the lens of the optical disc drive between (i) a first position relative to an optical disc and (ii) a second position relative to the optical disc, wherein first position is located a first distance from an outer surface of the optical disc, the first position corresponds to a position causing the lens to focus light on a data layer of the optical disc, the second position is located a second distance, different than the first distance, from the outer surface of the optical disc, and the second position corresponds to a position causing the lens to focus light on the outer surface of the optical disc, receive a measurement of light reflected by the optical disc while the lens is in the second position, and determine the cleanliness of the lens based on the measurement of the light reflected by the optical disc while the lens is in the second position.