0645043-A1 is referenced by 4 patents and cites 1 patents.

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
EP19940902519 19930604
Publication Number
0645043 (A1)
Application Date
June 4, 1993
Publication Date
March 29, 1995
Inventor
Johnson Paul R
US
Short Robert
US
Bero James
US
Thomas Fred Charles
US
Assignee
Minnesota Mining & Mfg
US
IPC
G11B 11/12
G11B 11/10
G01D 05/34
G11B 13/04
G11B 33/00
G11B 21/10
G11B 13/00
G11B 11/00
G11B 05/82
G11B 05/596
B23K 26/02
G11B 33/10
G11B 21/10
G11B 13/04
G11B 11/105
G11B 05/82
G11B 05/596
B23K 26/03
G11B 11/10
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