Tropel Corporation
24Patents
0Active
24Granted
31Portfolio score
Filing activity: Jan 31, 1980 → Nov 9, 2000
Most-cited patents
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US6191887A | Laser illumination with speckle reduction | Physics | 186 | Expired |
| US5353322A | Lens system for X-ray projection lithography camera | Physics | 74 | Expired |
| US5650877A | Imaging system for deep ultraviolet lithography | Physics | 61 | Expired |
| US4277141A | Multifaceted mirror and assembly fixture and method of making such mirror | Emerging Cross-Sectional Technologies | 42 | Expired |
| US6560039B1 | Double mirror catadioptric objective lens system with three optical surface multifunction component | Physics | 36 | Expired |
| US5416586A | Method of testing aspherical optical surfaces with an interferometer | Physics | 35 | Expired |
| US5923425A | Grazing incidence interferometry for measuring transparent plane-parallel plates | Physics | 29 | Expired |
| US5982475A | Raster-scan photolithographic reduction system | Physics | 27 | Expired |
| US5757493A | Interferometer with catadioptric imaging system having expanded range of numerical aperture | Physics | 24 | Expired |
| US4325637A | Phase modulation of grazing incidence interferometer | Physics | 21 | Expired |
| US5654798A | Interferometric measurement of surfaces with diffractive optics at grazing incidence | Physics | 20 | Expired |
| US5909282A | Interferometer for measuring thickness variations of semiconductor wafers | Physics | 17 | Expired |
| US5793488A | Interferometer with compound optics for measuring cylindrical objects at oblique incidence | Physics | 11 | Expired |
| US5991035A | Interferometric method of measuring toric surfaces at grazing incidence | Physics | 9 | Expired |
| US5889591A | Interferometric measurement of toric surfaces at grazing incidence | Physics | 7 | Expired |
| US5684594A | Object fixturing in interferometer | Physics | 7 | Expired |
| US5719676A | Diffraction management for grazing incidence interferometer | Physics | 6 | Expired |
| US5724137A | Fringe pattern discriminator for interferometer using diffraction gratings | Physics | 6 | Expired |
| US5777738A | Interferometric measurement of absolute dimensions of cylindrical surfaces at grazing incidence | Physics | 6 | Expired |
| US5532821A | Testing of recessed surfaces at grazing incidence | Physics | 3 | Expired |
| US6456384B1 | Moiré interferometer with overlapping illumination and imaging systems | Physics | 3 | Expired |
| US6043886A | Interferometric method of measuring toric surfaces at grazing incidence with phase shifting | Physics | 3 | Expired |
| US5349434A | Method of measuring artifact taper | Physics | 2 | Expired |
| US5909281A | Interferometric measurement of surfaces with diffractive optics and planar wavefront imaging | Physics | 2 | Expired |
Source: USPTO / EPO open patent data. Counts and citation impact are objective bibliographic measures.