Apparatus and method for characterizing defects in a transparent substrate
AssigneeCorning Incorporated
InventorsPhilip Robert LeBlanc, Vitor Marino Schneider, Correy Robert Ustanik
Life of this patent
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Abstract
An apparatus and method for detecting defects in a transparent substrate by simultaneously using a combination of bright field and dark field light sources for illuminating the substrate. The apparatus is capable of detecting both inclusions and surface defects simultaneously while the substrate is in motion, simplifying the characterization of substrates in a manufacturing setting.
Claims16
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.
An apparatus for detecting defects in a transparent substrate comprising:
- a first bright field light source arranged to direct a first bright field light through a back surface of the transparent substrate;
- a second bright field light source arranged to direct a second bright field light through a front surface of the transparent substrate;
- a first dark field light source arranged to directing a dark field light though the front surface of the transparent substrate;
- a scanning imaging camera arranged opposite the front side surface of the transparent substrate for simultaneously receiving the first and second bright field lights, and dark field light from the first dark field light source scattered by a defect in an interior of the transparent substrate;
- and
- a translating means for translating the substrate relative to the imaging system.
An apparatus for detecting defects in a transparent substrate comprising:
- first and second white light sources for illuminating an interior portion of the transparent substrate in the bright field of the imaging system, the first and second light sources arranged opposite front and back surfaces of the transparent substrate, respectively;
- first and second dark field light sources arranged opposite the front and back surfaces of the transparent substrate, respectively;
- a line scanning camera arranged opposite one of the front or back surfaces for scanning the transparent substrate;
- a translating means for translating the transparent substrate relative to the scanning imaging camera while the scanning imaging system is scanning the transparent substrate;
- and
- wherein the line scanning camera simultaneously detects light from the first and second bright field light sources and the first and second dark field light sources to detect defects on a surface and within an interior of the transparent substrate.
Dependencies are inferred from the claim text.