Optics: measuring and testing – Inspection of flaws or impurities – Surface condition
Patent
1997-04-28
2000-08-08
Pham, Hoa Q.
Optics: measuring and testing
Inspection of flaws or impurities
Surface condition
3562375, G01N 2188
Patent
active
061009717
ABSTRACT:
A laser based inspection tool (LIT) for inspecting planar surfaces is described. In a preferred embodiment the LIT can simultaneously inspect both planar surfaces of disks for use in disk drives. In an embodiment of the invention, the incident beam is directed onto the surface to be inspected at an angle slightly offset from perpendicular so that the reflected beam is physically separated from the incident beam. Although slightly offset the reflected beam is routed back through the telecentric lens and scanner which are used for the incident beam. Preferably an aperture mask is placed in the path of the reflected beam and the incident beam to limit the cone of scattered light. Since the incident and reflected beams are physically separated, there may be an aperture for each beam, but the two masks may be physically connected. The aperture masks may also be used for alignment adjustments of the beams.
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Imaino Wayne Isami
Juliana, Jr. Anthony
Latta Milton Russell
Lee Charles H.
Leung Wai Cheung
International Business Machines - Corporation
Knight G. Marlin
Pham Hoa Q.
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