A through-the-lens method and system for focusing a projected image onto an imaging surface employs a confocal process and apparatus. Electromagnetic radiation projected through a subresolution aperture of origin located in an object plane passes through a confocal imaging device which forms an image...http://www.google.fr/patents/US5306902?utm_source=gb-gplus-shareBrevet US5306902 - Confocal method and apparatus for focusing in projection lithography
Confocal method and apparatus for focusing in projection lithography
