Patent ID: 7567344

Claim:
A method for detecting defects in a transparent substrate comprising: providing a transparent substrate comprising a front surface and a back surface; illuminating an interior portion of the transparent substrate with at least one light source arranged to provide dark field illumination of the interior portion relative to a scanning imaging system; illuminating the transparent substrate interior portion with at least one light source arranged to provide bright field illumination of the interior portion relative to the scanning imaging system, wherein light comprising the bright field illumination enters the interior portion through the transparent substrate front surface and is reflected from the transparent substrate back surface within the interior portion of the transparent substrate; translating the transparent substrate relative to the scanning imaging system; and simultaneously detecting the light from the at least one bright field light source reflected from the back surface of the transparent substrate and light scattered by a defect within the interior portion illuminated by the dark field illumination by scanning the transparent substrate with the scanning imaging system while the transparent substrate is translated.