INSPECTING PHOTOMASKS FOR DUST
Disclosed is an apparatus for inspecting negatives which is provided with a laser beam generating source, a scanner for scanning the laser beam, a holding device for holding a negative having a pattern formed in a reflective area on a first surface of a transparent plate and transferring the negativ...
Saved in:
Main Author | |
---|---|
Format | Patent |
Language | English |
Published |
07.01.1987
|
Edition | 4 |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Disclosed is an apparatus for inspecting negatives which is provided with a laser beam generating source, a scanner for scanning the laser beam, a holding device for holding a negative having a pattern formed in a reflective area on a first surface of a transparent plate and transferring the negative in a direction perpendicular to the scanning direction of the laser beam, a first converging lens for converging the laser beam on said first surface, a second converging lens for converging on a first photocell the beam transmitted through the negative, a third converging lens for converging on a second photocell the beam reflected by the first surface of the negative, and a comparator for comparing a first signal stream put out from the first photocell and a second signal stream put out from the second photocell and detecting an undesirable adhering matter. |
---|---|
Bibliography: | Application Number: GB19830007940 |