Issued Patents 1997
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5682239 | Apparatus for detecting positional deviation of diffraction gratings on a substrate by utilizing optical heterodyne interference of light beams incident on the gratings from first and second light emitters | Kenji Saitoh, Koichi Sentoku | 1997-10-28 |
| 5625453 | System and method for detecting the relative positional deviation between diffraction gratings and for measuring the width of a line constituting a diffraction grating | Yoshiaki Ohtsu, Kenji Saitoh, Koichi Sentoku | 1997-04-29 |
| 5610718 | Apparatus and method for detecting a relative displacement between first and second diffraction gratings arranged close to each other wherein said gratings have different pitch sizes | Koichi Sentoku, Noriyuki Nose, Minoru Yoshii, Kenji Saitoh | 1997-03-11 |