Patent ID: 7099002

Claim:
A defect detector, comprising: a first optical system including: a first light source configured to irradiate a surface of a subject with coaxial incident-light while scanning the subject, and a first imaging device configured to receive light regularly reflecting from the subject and change the light to a first electrical signal to form a first electrical image; a second optical system including: a second light source configured to irradiate the surface of the subject with inclined light while scanning the subject, and a second imaging device configured to receive light scattered at the subject and to change the light to a second electrical signal to form a second electrical image, wherein the inclined light of the second light source does not meet the coaxial incident-light of the first light source; a computer configured to compare the first electrical signal with a predetermined first threshold to detect a concavo-convex defect on the surface of the subject, and to compare the second electrical signal with a predetermined second threshold to detect a blocky color defect on the surface of the subject; and a storage device, wherein the computer is further configured to process the first electrical image to determine a first position of the concavo-convex defect and the second electrical image to determine a second position of the blocky color defect, the computer is further configured to store the first and second positions in the storage device, and the computer is further configured to compare the first position with the second position, and when the first and the second positions are the same, the computer is configured to compare the first electrical signal with a predetermined third threshold to detect the concavo-convex defect and the second electrical signal with a predetermined fourth threshold to detect the blocky color defect.