An apparatus and method for etching a point on the surface of a magnetic medium to reduce the reflectivity of the point and for verifying that proper etching occured. A light source (40) provides a collimated incident beam of light (42). The incident beam is focused to a point on the medium (57) and a portion of the beam is reflected. The reflected beam (67) is separated from the incident beam and the intensity is compared to a threshold value and verification is indicated if the measured intensity exceeds the threshold value.

Title
Apparatus for and method of verifying etching of optical servo information on magnetic media
Application Number
PCT/US1993/005355
Publication Number
1993/026004
Application Date
June 4, 1993
Publication Date
December 23, 1993
Inventor
Johnson Paul R
Short Robert
Bero James
Thomas Fred Charles
Agent
KURTZ Richard E
Assignee
Minnesota Mining And Manufacturing Company
IPC
G11B 05/82
G11B 05/596
G11B 33/10
B23K 26/03
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