GRADIENT INDEX LENS ARRAY WITH IMPROVED EXPOSURE UNIFORMITY

Publishing Venue

Xerox Disclosure Journal

Abstract

Imaging systems which utilize gradient index fibers in a lens array are inherently subject to a problem of non-uniformity of exposure of an image at an imaging plane. Figure 1 illustrates a configuration wherein the orientation of a lens array is changed relative to an object and image plane. In this figure, which shows a top view of the lens 4 through an object plane (not shown), the lens array is shown in an original position 40 which is vertically oriented in a first plane normal to the object and image plane 16 and in a new position 42 still normal to the object and image plane but now lying in a second plane separated to an angle 0 with respect to the

Volume 6 Number 2 March/April 1981 75

GRADIENT INDEX LENS ARRAY WITH IMPROVED EXPOSURE UNIFORMITY (Cont'd)

Imaging systems which utilize gradient index fibers in a lens array are inherently subject to a problem of non-uniformity of exposure of an image at an imaging plane. Figure 1 illustrates a configuration wherein the orientation of a lens array is changed relative to an object and image plane. In this figure, which shows a top view of the lens 4 through an object plane (not shown), the lens array is shown in an original position 40 which is vertically oriented in a first plane normal to the object and image plane 16 and in a new position 42 still normal to the object and image plane but now lying in a second plane separated to an angle 0 with respect to the first normal plane.

The exposure at the image plane changes, as shown in Figure 2. The change in orientation has shifted the fiber exposure profiles 20a, 20b, . . . ^of each end in exposure zone 18 in a counterclockwise direction, altering the exposure that points P and PI, traveling at a speed V, will receive as they pass through the zone. An optimum value of Ocan be selected in accordance with the equation:

cos o=

where rA is the gradient index constant of the gradient index fibers, L is the fiber length in the 2 direction (into the page), b is a spacing factor equal to the separation between fiber centers divided by the fiber diameter (2...