IMPROVED RESOLUTION FOR A GRADIENT INDEX LENS ARRAY
Original Publication Date: 1989-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
Gradient index lens arrays are used as compact imaging devices in conjunction with RIS and ROS image bar systems. Typically the spacial density of these RIS/ROS devices is in the range of 240-400 spi. At higher spatial densities, image quality (MTF) begins to deteriorate. It is proposed to increase the spatial density to 600 spi by reducing the maximum field (k) of the lens array by increasing the length 1 of the gradient index fibers which comprise the array. The amount of overlap between adjacent fibers is reduced and less fibers contribute to any one point in the image. The resulting increase in a radiance and exposure modulation is compensated for by oscillating the lens laterally during an exposure interval. While any periodic osculation in the array direction will improve the uniformity, an optimum motion for maximum modulation is given by the expression bR where b is the lens array inter-fiber spacing parameter and R is the fiber radius.