US4870635A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Precision measurement and positioning system for disk storage system
Assignee: International Business Machines Corp
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Filing: 1986-09-19
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Granted: 1989-09-26
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Expires: 2006-09-19
Abstract
Abstract The invention uses a small sized, low cost, high accuracy, semiconductor laser interferometer to position the transducer in a disc storage system. Light is reflected back over the path to be measured and directly back into the semiconductor laser. This causes the power present in the laser to be varied. Unexpectedly, the output of the photosensor associated with the laser has an asymmetric, sawtooth waveform.
Inventors
- 👤 Timothy R. Block
- 👤 Mark R. Enstrom
- 👤 Francis S. Luecke
- 👤 Karl A. Shidler
- 👤 Ronald L. Soderstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:15
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/48; G11B5/54; G11B5/55; G11B5/5521; G11B5/5526
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
29 words
An interferometric device for measuring distance and direction of motion between said device and a target surface comprising a semiconductor laser including a laser cavity for generating coherent radiation;
Claim 2
Dependent Claim
29 words
An interferometric device for measuring distance and direction of motion between said device and a target surface comprising a semiconductor laser including a laser cavity for generating coherent radiation;
Claim 3
Dependent Claim
105 words
means carried by said target surface to reflect radiation from said laser back to said laser cavity; measurement means for generating an output pulse train signal representative of optical conditions in said laser cavity; and signal processing means connected to said measurement means for converting said output pulse train signal into distance measurements and the direction of relative motion between said device and said target, said signal processing means including means for sensing pulses with a greater slope leading edge, indicative of relative motion in one direction and pulses with a greater slope trailing edge, indicative of motion in the direction opposite said one direction.
Claim 4
Dependent Claim
105 words
means carried by said target surface to reflect radiation from said laser back to said laser cavity; measurement means for generating an output pulse train signal representative of optical conditions in said laser cavity; and signal processing means connected to said measurement means for converting said output pulse train signal into distance measurements and the direction of relative motion between said device and said target, said signal processing means including means for sensing pulses with a greater slope leading edge, indicative of relative motion in one direction and pulses with a greater slope trailing edge, indicative of motion in the direction opposite said one direction.
Claim 5
Independent Claim
26 words
A device according to 1 wherein said signal processing means includes digital means for counting in response to said output signal and producing said distance measurements.
Claim 6
Independent Claim
26 words
A device according to 1 wherein said signal processing means includes digital means for counting in response to said output signal and producing said distance measurements.
Claim 7
Dependent Claim
19 words
A device according to claim 2 wherein said digital means counts in response to changes in said output signal.
Claim 8
Dependent Claim
13 words
A device according to claim 3 wherein digital means includes a programmed microprocessor.
Claim 9
Dependent Claim
24 words
A device according to claim 4 wherein said programmed microprocessor includes storage means having distance measurements stored at addresses corresponding to said output signals.
Claim 10
Dependent Claim
22 words
A device according to claim 4 wherein said programmed microprocessor processes said output signals to provide additional distance measurements intermediate said transitions.
Claim 11
Dependent Claim
24 words
A device according to claim 6 wherein said programmed microprocessor processes said output signals by interpolation to provide additional distance measurements intermediate said transitions.
Claim 12
Dependent Claim
137 words
An interferometric measurement and positioning system for a disk storage system comprising: a medium adapted for the storage of data; transducer means for coacting with said data; actuator means for positioning said transducer relative to said medium; a semiconductor laser for generating coherent radiation; collimating means for aligning the radiation generated by said laser; retroreflector means operable to move in synchronism with said transducer means and reflect at least a portion of said coherent radiation back into said laser; measurement means associated with said laser for generating an output signal including a sequence of pulses representative of a condition within said laser responsive to said reflected light; and signal processing means connected to said measurement means for converting said output signal into distance measurements and the direction of relative motion between said semiconductor laser and said retroreflector.
Claim 13
Dependent Claim
137 words
An interferometric measurement and positioning system for a disk storage system comprising: a medium adapted for the storage of data; transducer means for coacting with said data; actuator means for positioning said transducer relative to said medium; a semiconductor laser for generating coherent radiation; collimating means for aligning the radiation generated by said laser; retroreflector means operable to move in synchronism with said transducer means and reflect at least a portion of said coherent radiation back into said laser; measurement means associated with said laser for generating an output signal including a sequence of pulses representative of a condition within said laser responsive to said reflected light; and signal processing means connected to said measurement means for converting said output signal into distance measurements and the direction of relative motion between said semiconductor laser and said retroreflector.
Claim 14
Dependent Claim
56 words
An interferometric measurement and positioning system for a disk storage system as in claim 8 wherein said signal processing means includes means for sensing pulses with a greater slope leading edge, indicative of relative motion in one direction and pulses with a greater slope trailing edge, indicative of motion in the direction opposite said one direction.
Claim 15
Dependent Claim
36 words
A system according to claim 9 further including; actuator control means, connected to said signal processing means and responsive to said distance measurements, for driving said actuator to position said transducer for coaction with desired data.
Claim 16
Dependent Claim
53 words
A system according to claim 10 further including: means for supplying desired data position information to said signal processing means; and said signal processing means includes means for determining the distance and direction of movement of said transducer means required for coaction of said transducer means with said data at said desired position.
Claim 17
Dependent Claim
32 words
A system according to claim 11 wherein: said signal processing means includes means responsive to said output signal for maintaining said transducer in position for coaction with data at said desired position.
Claim 18
Dependent Claim
14 words
A system according to claim 9 wherein said actuator means comprises a rotary actuator.
Claim 19
Dependent Claim
14 words
A system according to claim 9 wherein said actuator means comprises a linear actuator.
Claim 20
Dependent Claim
14 words
A system according to claim 9 wheren said actuator means comprises a stepper motor.
Claim 21
Dependent Claim
45 words
A system according to claim 9 wherein said retroreflector means is mechanically coupled to said transducer to move in synchronism therewith and provide a change in the length of the path followed by the reflected radiation which approximates twice the distance moved by said transducer.
Claim 22
Dependent Claim
16 words
A system according to claim 9 wherein said retroreflector means is mechanically coupled to said transducer.
Claim 23
Dependent Claim
37 words
A system according to claim 9 wherein said retroreflector means is mechanically coupled to said transducer to move in synchronism therewith and the path followed by said reflected radiation is coaxial with the movement of said transducer.
Claim 24
Dependent Claim
41 words
A system according to claim 9 wherein said retroreflector means is mechanically copled to said transducer to move in synchronism therewith and the path followed by said reflected radiation is at an angle with respect to the movement of said transducer.
Claim 25
Dependent Claim
12 words
A system according to claim 19 wherein said angle is 90 degrees.
References Cited (Backward Citations)
JPS52435A
Cited
US4377036A
Cited
US4371902A
Cited
US4481613A
Cited
US4452533A
Cited
US4495608A
Cited
US4498775A
Cited
US4509858A
Cited
US4531167A
Cited
US4706234A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-25 | 1993-03-27 | 1993-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-25 | 1997-03-27 | 1997-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-25 | 2001-03-27 | 2001-09-26 | $7700.00 | Window Closed / Lapsed |