Apparatus and method for detection of contaminant particles or component defects

An apparatus for detecting particles on or defects in a transparent media, comprising:

• at least one light source;
• a first array of light-sensitive elements in which each of the elements are configured to produce an electrical signal indicating a characteristic value based on light incident on the element, the first array being disposed a predetermined distance from the at least one light source, thereby permitting positioning of the transparent media between the at least one light source and the first array;
• an addressing circuit configured to read the characteristic values produced by each element;
• an analog-to-digital converter circuit configured to digitize the characteristic values, thereby producing digitized values;
• and
• a processor configured to process the digitized values to determine whether a particle or defect is present,
• wherein the at least one light source is configured to produce light to illuminate the particle or defect,
• wherein, during detection, the first array receives the light passing through the transparent media and a shadow cast by the particle or defect, and
• wherein the processor determines whether the particle or defect is present based at least on a position of the shadow cast by the particle or defect on the first array.