A method and device to create discrete, axially displaced focal regions to provide a sharp focus at two separated planes.
Problem Solved by this Technology
Current systems for the simultaneous acquisition of two separate surface images require special lenses, crystals, or data storage and processing equipment. The necessary equipment tends to be bulky, expensive, and easily damaged.
This method can enable the simultaneous inspection of two faces of high quality glass plates, such as those used in liquid crystal displays. Another such use would be in the inspection of semiconductor masks and reticles, which often must be examined at two planes, for example at both the top and bottom of a trench. It could be used in a confocal imaging system to provide simultaneous acquisition of two separate surface images enabling cell imaging at two different axial depths, without requiring later image registration. It could also enable a differential interference contrast microscope without the use of anisotropic crystals, and in an optical data storage system for interrogating two layers of an optical data storage material at the same time.
URV Reference Number: 2-11150-07020