Non-contact servotrack writing with phase sensitive detection
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United States of America Patent
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Nov 23, 1999
Grant Date -
N/A
app pub date -
Mar 4, 1997
filing date -
Mar 4, 1997
priority date (Note) -
Expired
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Abstract
A servotrack writing apparatus (10) for use on computer disk drive workpieces (12). A writer controller (58) puts the writing apparatus (10) in the role of master to direct the workpiece (12) as a slave to position its read-write head (36) and to write the servotracks. A tracking section (54) provides a modulated light beam (72) from which a reflected portion is detected by a bi-cell photo sensor (70) and processed in the writer controller (58) to determine the position of a thru-hole (40) or a detection region (42) in the actuator arm (24) of the workpiece (12). The writer controller (58) may use a lock-in amplifier (102, 104) for the processing the reflected portion of the light beam (72). A reference arm (44) is locked and moved in a synchronous relationship with the actuator arm (24). A measurement section (56) determines the position of the reference arm (44), and may include an interferometer system (122) having a differential head (128) and a differential target (124), to permit increased resolution and nulling of errors. The interferometer system (122) may also use multiple frequency techniques to further increase resolution.
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- 15 United States
- 10 France
- 8 Japan
- 7 China
- 5 Korea
- 2 Other
Patent Owner(s)
- EXCEL PRECISION, INC.
International Classification(s)
Inventor(s)
Inventor Name | Address | # of filed Patents | Total Citations |
---|---|---|---|
Chi, Jean | San Jose, CA | 1 | 7 |
Hopson, Mervyn L | Cupertino, CA | 1 | 7 |
Song, Hubert | Sunnyvale, CA | 13 | 114 |
Tsai, John C | Saratoga, CA | 47 | 567 |
Yan, Kam-Fung | Mountain View, CA | 1 | 7 |
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