Abstract: An optical inspection apparatus operates at high speed at very high resolution for detecting defects in transparent disks in a production environment. These transparent disks are of the type commonly used as disk platters in hard disk drives. This apparatus uses a laser beam directed to a polygon scanner, which provides a linear scan of the beam along a radius of the disk. The disk to be inspected is rotated such that its entire surface passes the scan path of the laser beam. The laser beam, after passing through the unit to be inspected, is directed to a parallel detector array, which detects changes in the nominal Gaussian distribution of the laser beam that correspond to defects in the surface of the transparent disk above a programmable threshold level. This parallel detection method allows the inspection apparatus to identify defects much smaller than the diffraction limits of the optics used, and will accurately identify changes of the laser beam caused by defects in the disk.

Abstract: An optical inspection apparatus operates at high speed at very high resolution for detecting defects in reflective disks in a production environment. These reflective disks are of the type commonly used as disk platters in hard disk drives. This apparatus uses a laser which provides a light beam directed to a polygon scanner, which provides a linear scan of the beam along a radius on both sides of the disk by using two mirrors to direct the light beam. The disk to be inspected is rotated such that its entire surface passes the scan path of the light beam. The light beam is reflected off the reflective disk, and returns to the scanning optics and the polygon scanner in a path coincident with the transmitted light beam.

Abstract: An optical inspection apparatus operates at high speed at very high resolution for detecting defects in transparent flat panels in a production environment. This apparatus uses a laser which provides a light beam directed to a polygon scanner, which provides a linear scan of the beam along the width of the flat panel. The flat panel to be inspected is moved such that its entire surface passes the scan path of the light beam. The light beam passes through the transparent flat panel, and is reflected off a spherical mirror, back through the transparent flat panel, and returns to the scanning optics and the polygon scanner in a path coincident with the transmitted light beam.

Abstract: An optical inspection apparatus operates at high speed at very high resolution for detecting defects in flat, polished media in a production environment. The configuration of the first embodiment is used to inspect transparent disks such as those used as disk platters in hard disk drives. The configuration of the second embodiment is used to inspect reflective disks. The configuration of the third embodiment is used to inspect transparent flat panels such as those commonly used in Liquid Crystal Display (LCD) panels. All embodiments use a laser providing a light beam directed to a polygon scanner, which provides a linear scan of the beam. The unit to be inspected is moved such that its entire surface passes the scan path of the light beam. The light beam, after contacting the unit to be inspected, is directed to a parallel detector array, which detects changes in the nominal Gaussian distribution of the light beam that correspond to defects above a programmable threshold level.