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DOCUMENT IMAGING SYSTEM USING A THREE-DIMENSIONAL RELATIVE ILLUMINATION CORRECTOR

IP.com Disclosure Number: IPCOM000025623D
Original Publication Date: 1986-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Document File: 4 page(s) / 146K

Publishing Venue

Xerox Disclosure Journal

Abstract

This disclosure relates to a document imaging system which incorporates a three-dimensional corrector element positioned along an optical path to correct for cos4 illumination falloff and other illumination non-uniformities of the system projection lens so as to provide a uniform exposure level at the image plane

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 55% of the total text.

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XEROX DISCLOSURE JOURNAL

DOCUMENT IMAGING SYSTEM Proposed Classification USING A THREE-DIMENSIONAL
RELATIVE ILLUMINATION
CORRECTOR
Robert P. Loce
Melvin E. Deibler

U.S. Cl. 355/8 Int. C1. G03G 15/28

FIG lo

I/2 FIELD

A

FIG lb FlG lc

AXIS

&

Volume 11 Number 5 September/October 1986 239

[This page contains 1 picture or other non-text object]

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DOCUMENT IMAGING SYSTEM USING A THREE-DIMENSIONAL RELATIVE ILLUMINATION CORRECTOR (Cont'd)

2 40

    XEROX DISCLOSURE JOURNAL Volume I1 Number 5 September/October 1986

[This page contains 1 picture or other non-text object]

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DOCUMENT IMAGING SYSTEM USING A THREE-IDTMENSIONAL RELATIVE ILLUMINATION CORRECTOR (Cont'd)

This disclosure relates to a document imaging system which incorporates a three-dimensional corrector element positioned along an optical path to correct for cos4 illumination falloff and other illumination non-uniformities of the system projection lens so as to provide a uniform exposure level at the image plane

The general principle is demonstrated by viewing a three-dimensional cone in the object space of an imaging system as shown in Figure 1 Referring to Figure 1, there is shown an object plane 10, a projection lens 12 and a photosensitive image plane 14. The field of view of lens 12 extends from point A to point C with point A being the center axial point A rotationally symmetrical, three-dimensional cone 16 is coincldent with the optical axis of the lens at a distance hl from the entrance pupil The cone will prevent light reflected from the document from reaching the image plane in a varying manner, depending on the position of the object point and the cone shape and position Cone 16 1s chosen to have a geometry and location such that the reduction in energy reaching the image plane from the on-axis location (point
A) to the full field defined by points B and C will vary from the zero vignetting at full field shown in Figure la to the partial vignetting shown in Figure lb to the full vignetting on-axis shown in Figure lc By proper desrgn, cone 16 can be used to compensate for the effects of cos4 illumination falloff at the edges of the field The exact shape of the cone and its position along the opttcal axis is dependent on the desrgn of the lens

For some systems, an optimum shape is a 6th order parabolic parabollzed in a conve...