GRADIENT INDEX LENS ARRAY FOR FORMING INTENSITY IMAGES FROM PHASE OBJECTS
Original Publication Date: 1982-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
The figure shows an optical imaging system which uses a gradient index lens array for producing an intensity modulated image from a phase object. In the figure, an object lying in plane 10 is illuminated by a source of collimated light. A gradient index lens array 12, comprising a plurality of gradient index fiber lenses is placed between phase object plane 10 and an intensity image plane 14. Array 12 is designed so that such individual fibers simultaneously produce a 1:l erect image of the object at the imaging plane 14. Each lenslet is also designed to have an external second focal point. A plurality of stops, or apertures, 16 are then placed at these second focal points to block the residual collimated light, reflected or transmitted from plane 10, from reaching plane 14. This causes a dark image to appear in image areas where optical variation in object phase is nearly zero. Alternatively, contrast reversal is achieved by blocking all except the residual collimated light by placing an appropriately designed mask (not shown) at the second focal points.