Browse Prior Art Database

Visual Comparison Microscope

IP.com Disclosure Number: IPCOM000094390D
Original Publication Date: 1966-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Rottman, HR: AUTHOR

Abstract

This microscope aligns two or more transparent or semi-transparent masks. The microscope can be adjusted to bring two masks lying in spaced planes into sharp focus.

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 81% of the total text.

Page 1 of 2

Visual Comparison Microscope

This microscope aligns two or more transparent or semi-transparent masks. The microscope can be adjusted to bring two masks lying in spaced planes into sharp focus.

In photoetching and similar fields the accurate registration of masks is of importance. Normally the registration is achieved with a microscope of low magnification and a large depth of field. The degree of magnification of the microscope is limited by the resultant depth of field. The depth of field of a microscope of high magnification and resolution is not capable ordinarily of simultaneously bringing two masks in slightly spaced planes in sharp focus. This limits the accuracy of registration.

This microscope illuminates plates P1 and P2 lying in planes Al and A2, respectively, with light source LS in combination with condenser C. O is an objective lens with a numerical aperture in the order of 0.2 or greater. P1 in plane A1 is viewed distinctly by the observer through lenses O, E2, and E3. P2 in plane A2 is viewed through lenses O, E1, and E3. Lenses E1 and E2 are chosen and positioned so that the magnification of P1 and P2 is the same.

Beam splitters B1 and B2 and surface reflection mirrors M1 and M2 serve to split and reunite the light beams traversing through O. E1 or E2 can be a zoom lens or a negative lens if desired. Color filters can be inserted in the separate light paths so that the resultant superimposed images appear in different colors and facilitate fine r...