Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Device for Inspecting Cleaned Surfaces

IP.com Disclosure Number: IPCOM000095804D
Original Publication Date: 1964-Jul-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Lipschutz, LD: AUTHOR

Abstract

Inspection of magnetic recording tape for foreign particles is accomplished by using a carefully precleaned and reeled transparent tape 10 as a protection cover over the sample tape 12 to be examined. The cover tape can have a contact adhesive along its edges to seal the clean surfaces from contamination.

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 89% of the total text.

Page 1 of 2

Device for Inspecting Cleaned Surfaces

Inspection of magnetic recording tape for foreign particles is accomplished by using a carefully precleaned and reeled transparent tape 10 as a protection cover over the sample tape 12 to be examined. The cover tape can have a contact adhesive along its edges to seal the clean surfaces from contamination.

The two tapes are pressed together by being drawn under tension over a cylindrical surface 14. An interference pattern is created by reflecting monochromatic light from the top and bottom surfaces of the tape. The light from source 15 is directed through collimating lens 16 and filter 17 to the tape surfaces by being reflected from a dichroic mirror 18. The reflected light from the top and bottom surfaces of the cover tape will interfere if the tapes are separated by a particle trapped between them. The tape is inspected not for the particles themselves, but for the much larger tents or areas of separation the particles produce between the two tapes. The diameter of the area of separation may be on the order of 100 times the diameter of the particle causing the separation so that there is magnification.

The interference pattern can be sharpened by coating the top Surface of the cover tape 10 with a partially reflecting layer.

The same result can be obtained without a sample cover by trapping the particle between a tape and a transparent cylindrical surface. The light must then be directed through the transparent surface. Th...