Microscope with Enhanced Depth of Field and 3–D Capability

In the summer of 1969, R. L. Gregory was working at Bell Labs, and suggested one might be able to increase the effective depth of field of a microscope if, instead of making the objective achromatic, one arranged that the different spectral colors come to foci at different distances from the lens. J. S. Courtney-Pratt suggested that one might then be able to view the image in 3-D by use of a simple binocular eyepiece modified to give a convergence of the images that varied with the spectral color. A 16-mm NA 0.4 objective has been made that gives a lateral resolution of 1 micro and a depth of field of 100 micro. 3-D displays present sharp images of objects with dark field illumination with depth magnification at any chosen value up to+/- 4 10,000x.