Browse Prior Art Database

CONSTANT MAGNIFICATION ZOOM LENS FOR AUTO FOCUSING

IP.com Disclosure Number: IPCOM000023477D
Original Publication Date: 1977-Dec-31
Included in the Prior Art Database: 2004-Mar-31
Document File: 2 page(s) / 221K

Publishing Venue

Xerox Disclosure Journal

Abstract

This concept relates to a constant magnification zoom lens for auto focusing. In an apparatus where photographic slides are copied, it is observed that the plane of the transparency varies slightly from slide to slide. A lens which accurately

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 100% of the total text.

Page 1 of 2

XEROX DISCLOSURE JOURNAL

CONSTANT MAGNIFICATION ZOOM LENS Proposed Classification

FOR AUTO FOCUSING U~S. C1~ 350/184
Earl V~ Jackson Int, Cl, G02b 15/00

This concept relates to a constant magnification zoom lens for
auto focusing. In an apparatus where photographic slides are
copied, it is observed that the plane of the transparency
varies slightly from slide to slide. A lens which accurately

resolves a first slide may require adjustment to accurately
resolve a second slide because of the slight change in the
plane of the transparency. The slight adjustment of the lens
to compensate for the change in transparency plane is normally
a movement of the lens either toward or away from the trans~
parency. This movement focuses the image but also changes the
magnification of the image.

In the present concept, a zoom lens is used and its focal
length is changed by moving one or more elements. Changes in
location of the plane of the transparency represent a change
in the total object~to~imagedistance. The lens is moved so
as to maintain a constant magnification and image location.
The small range of adjustment required should permit use of a
relatively simple zoom lens,

Volume 2 Number 6 November/December 1977 105

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

Page 2 of 2

                  XEROX DISCLOSURE JOURNAL
106 Volume 2 Number 6 November/December 1977

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