Patent ID: 6697152
Filing Date: 2004-02-24
Classification: G01N

Abstract:
An apparatus that detects removable particles initially on a first test surface, the removable particles being transferred to a portion of a tacky surface on a carrier by adhering and then removing the portion of the tacky surface from the first test surface, a first exposed surface being the portion of the tacky surface removed from the first test surface, and an unexposed surface being the first exposed surface prior to being adhered to and removed the first test surface, the apparatus comprising:a controller; a surface inspection means for transmitting to the controller a particulate signal coordinate for each particulate detected in a sensible field of view of the surface inspection means; a positioning means for receiving the carrier with the tacky surface, and for passing the portion of the tacky surface across the sensible field of view of the surface inspection means in response to positioning commands from the controller; a first calculation means for combining the particulate signal coordinates received by the controller with positioning commands to the positioning means, wherein the first calculation means assigns unexposed particle coordinates to particulate signal coordinates from the unexposed surface, and wherein the first calculation means assigns first exposed particle coordinates to particulate signal coordinates from the first exposed surface; a first memory means for storing unexposed particle coordinates from the first calculation means; and a second calculation means for combining first exposed particle coordinates from the first calculation means with unexposed particle coordinates from the first memory means to determine a number of removable particles initially on the first test surface; whereby particles with first exposed particle coordinates that have no corresponding unexposed particle coordinates comprise removable particles initially on the first test surface.