Patent US3716845A successfully refreshed from Google Patents.
US3716845A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical memory with interferometer tracking
Assignee: Honeywell Inc
•
Filing: 1972-03-09
•
Granted: 1973-02-13
•
Expires: 1992-03-09
Abstract
Abstract An optical mass memory utilizing a rotatable substrate is provided with improved tracking. An interferometer measures the distance between a reflective edge surface on the rotatable substrate and a reflective surface on a movable arm. The final lens for focusing the read-write light beam to a focused light spot on the memory medium is mounted on the movable arm. The electrical signal produced by the interferometer is compared to a track selection signal which is indicative of the desired distance between the reflective edge surface and the reflective surface, and a servo control signal is produced which is indicative of the difference of the electrical signal and the track selection signal. The movable arm is positioned in response to the servo control signal.
Inventors
- 👤 J Chaffin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 04:34
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0901; G11B7/085; G11B7/0857; G11B7/08582; G01; G01B; G01B2290/00; G01B2290/45
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
248 words
An optical memory comprising: a rotatable substrate having a memory surface and a reflective edge surface essentially orthogonal to the memory surface, a memory medium attached to the memory surface of the rotatable substrate and capable of having a plurality of tracks of bits of information recorded thereon, first motor means for rotating the substrate and the memory medium, movable arm means extending over the memory surface, the movable arm means being capable of motion in a direction essentially parallel to the memory surface and essentially orthogonal to the reflective edge surface, light source means for producing a light beam for reading and writing on the memory medium, final lens means for focusing the light beam to a focused light spot on the memory medium, final lens mounting means for mounting the final lens means to the movable arm means, a reflective surface attached to the movable arm means, interferometer means for measuring the relative distance between the reflective edge surface and the reflective surface and producing an electrical signal indicative of the relative distance, track selecting means for producing a track selection signal indicative of the desired distance between the reflective edge surface and the reflective surface, signal comparing means for receiving the electrical signal and the track selection signal and for producing a servo control signal indicative of a difference of the electrical signal and the track selection signal, and second motor means for positioning the movable arm means in response to the servo control signal.
Claim 2
Dependent Claim
248 words
An optical memory comprising: a rotatable substrate having a memory surface and a reflective edge surface essentially orthogonal to the memory surface, a memory medium attached to the memory surface of the rotatable substrate and capable of having a plurality of tracks of bits of information recorded thereon, first motor means for rotating the substrate and the memory medium, movable arm means extending over the memory surface, the movable arm means being capable of motion in a direction essentially parallel to the memory surface and essentially orthogonal to the reflective edge surface, light source means for producing a light beam for reading and writing on the memory medium, final lens means for focusing the light beam to a focused light spot on the memory medium, final lens mounting means for mounting the final lens means to the movable arm means, a reflective surface attached to the movable arm means, interferometer means for measuring the relative distance between the reflective edge surface and the reflective surface and producing an electrical signal indicative of the relative distance, track selecting means for producing a track selection signal indicative of the desired distance between the reflective edge surface and the reflective surface, signal comparing means for receiving the electrical signal and the track selection signal and for producing a servo control signal indicative of a difference of the electrical signal and the track selection signal, and second motor means for positioning the movable arm means in response to the servo control signal.
Claim 3
Dependent Claim
248 words
An optical memory comprising: a rotatable substrate having a memory surface and a reflective edge surface essentially orthogonal to the memory surface, a memory medium attached to the memory surface of the rotatable substrate and capable of having a plurality of tracks of bits of information recorded thereon, first motor means for rotating the substrate and the memory medium, movable arm means extending over the memory surface, the movable arm means being capable of motion in a direction essentially parallel to the memory surface and essentially orthogonal to the reflective edge surface, light source means for producing a light beam for reading and writing on the memory medium, final lens means for focusing the light beam to a focused light spot on the memory medium, final lens mounting means for mounting the final lens means to the movable arm means, a reflective surface attached to the movable arm means, interferometer means for measuring the relative distance between the reflective edge surface and the reflective surface and producing an electrical signal indicative of the relative distance, track selecting means for producing a track selection signal indicative of the desired distance between the reflective edge surface and the reflective surface, signal comparing means for receiving the electrical signal and the track selection signal and for producing a servo control signal indicative of a difference of the electrical signal and the track selection signal, and second motor means for positioning the movable arm means in response to the servo control signal.
Claim 4
Dependent Claim
248 words
An optical memory comprising: a rotatable substrate having a memory surface and a reflective edge surface essentially orthogonal to the memory surface, a memory medium attached to the memory surface of the rotatable substrate and capable of having a plurality of tracks of bits of information recorded thereon, first motor means for rotating the substrate and the memory medium, movable arm means extending over the memory surface, the movable arm means being capable of motion in a direction essentially parallel to the memory surface and essentially orthogonal to the reflective edge surface, light source means for producing a light beam for reading and writing on the memory medium, final lens means for focusing the light beam to a focused light spot on the memory medium, final lens mounting means for mounting the final lens means to the movable arm means, a reflective surface attached to the movable arm means, interferometer means for measuring the relative distance between the reflective edge surface and the reflective surface and producing an electrical signal indicative of the relative distance, track selecting means for producing a track selection signal indicative of the desired distance between the reflective edge surface and the reflective surface, signal comparing means for receiving the electrical signal and the track selection signal and for producing a servo control signal indicative of a difference of the electrical signal and the track selection signal, and second motor means for positioning the movable arm means in response to the servo control signal.
Claim 5
Dependent Claim
25 words
The optical memory of claim 1 wherein the rotatable substrate is a circular disc having a planar memory surface and a curved reflective edge surface.
Claim 6
Dependent Claim
14 words
The optical memory of claim 1 wherein the rotatable substrate is a cylindrical drum.
Claim 7
Dependent Claim
118 words
The optical memory of claim 1 wherein the interferometer means comprises: interferometer light source means for directing a first interferometer light beam to the reflective surface and a second interferometer light beam to the reflective edge surface, beam combining means for receiving the first and second interferometer light beams from the reflective surface and the reflective edge surface and for combining the first and second interferometer light beams to produce an interference fringe pattern, interference fringe counting means for counting the number of interference fringe maxima and minima from a predetErmined reference fringe, and for producing a digital signal indicative of the number, and first digital-to-analog converter means for converting the digital signal to an analog electrical signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-13 | 1976-08-14 | 1977-02-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-13 | 1980-08-14 | 1981-02-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-13 | 1984-08-14 | 1985-02-13 | $7700.00 | Window Closed / Lapsed |