Patent ID: 7684053

Claim:
An optical displacement sensor for measuring distance or surface displacement of an object by surface profile scanning comprising: an optical source, a first optical detector, a second optical detector, a first focusing lens and a second focusing lens, said optical source being located intermediate said first and said second optical detectors, said first optical detector being forward of said optical source and said second optical detector being rearward of said optical source, and said first focusing lens and first optical detector being arranged to collect light coming from said object along a first direction, and said second focusing lens and second optical detector being arranged to collect light coming from said object along a second direction, said first and second directions being divergent from said object, and said first and second focusing lens and first and second optical detectors being arranged to collect light emitted by said optical source when scattered by and reflected from surface of said object; wherein said first and second focusing lens and first and second detectors are arranged so that when said optical source emits light towards a depressed surface proximal a step, only light reflected or scattered from said depressed surface and to be collected by one of said optical detectors will be blocked or partially blocked by said step; and wherein said first and second detectors are arranged such that relative movements between said optical source and said object along a scanning direction will output information corresponding to the profile of said surface of said object.