US3781905A
Expired / Lapsed
US
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Optical mass memory
Assignee: Honeywell Inc
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Filing: 1972-09-22
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Granted: 1973-12-25
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Expires: 1992-09-22
Abstract
Abstract An optical mass memory of the Curie point writing type which utilizes a pulsed laser to write on low temperature phase manganese bismuth film. The duration of the laser pulses is less than 10 nanoseconds. Greatly reduced readout signal level variation due to crystallographic phase change is achieved.
Inventors
- 👤 E Bernal
- 👤 Chen Di
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:55
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10582; G11B11/10586; G11B11/10502; G11B11/10504; G11B11/10508; G11B11/10532; G11B11/10534; G11B11/10536; G11B11/10541; G11B11/10543; G11B11/1055; G11B11/10556; G11B11/10595
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
97 words
A bit-by-bit optical mass memory of the Curie point writing type having a memory medium of low temperature phase MnBi film and being characterized by greatly reduced readout signal level variation due to crystallographic phase changes, the optical mass memory comprising: light source means for producing light pulses having an intensity sufficient to heat a region of the MnBi film above the low temperature phase Curie point, the light pulses each having a duration of less than 10 nanoseconds; and light pulse directing means for directing a light pulse to a predetermined region of the MnBi film.
Claim 2
Dependent Claim
97 words
A bit-by-bit optical mass memory of the Curie point writing type having a memory medium of low temperature phase MnBi film and being characterized by greatly reduced readout signal level variation due to crystallographic phase changes, the optical mass memory comprising: light source means for producing light pulses having an intensity sufficient to heat a region of the MnBi film above the low temperature phase Curie point, the light pulses each having a duration of less than 10 nanoseconds; and light pulse directing means for directing a light pulse to a predetermined region of the MnBi film.
Claim 3
Dependent Claim
53 words
The optical mass memory of claim 1 and further comprising: light source control means for controlling the production of light pulses by the light source means; address control means for controlling the light pulse directing means; and memory control means for coordinating the operation of light source control means and address control means.
Claim 4
Dependent Claim
62 words
The optical mass memory of claim 2 wherein the light source means produces a continuous train of light pulses, and wherein the light source control means comprises: shutter means for allowing selected individual light pulses of the continuous train to impinge upon the MnBi film in response to a shutter control signal; and shutter control means for producing the shutter control signal.
Claim 5
Dependent Claim
45 words
The optical mass memory of claim 3 further comprising pulse monitoring means for monitoring the continuous train of light pulses and for providing a synchronizing pulse signal to the memory control means, the synchronizing pulse signal being indicative of each pulse of the continuous train.
Claim 6
Dependent Claim
16 words
The optical mass memory of claim 4 wherein the light source means is a mode-locked laser.
Claim 7
Dependent Claim
28 words
The optical mass memory of claim 5 wherein the mode-locked laser comprises: a gas laser havinG a laser cavity; and an acousto-optic mode-locker positioned in the laser cavity.
Claim 8
Dependent Claim
26 words
The optical mass memory of claim 6 and further comprising clock means for providing a timing signal to the memory control means and the acousto-optic mode-locker.
Claim 9
Dependent Claim
64 words
The optical mass memory of claim 4 wherein the pulse monitoring means comprises: beam splitter means positioned between the light source means and the shutter means for splitting off a portion of the continuous train of light pulses; and detector means for receiving the portion of the continuous train and for producing a synchronizing pulse signal indicative of each pulse of the continuous train.
Claim 10
Dependent Claim
16 words
The optical mass memory of claim 1 wherein the light source is a cavity dump laser.
Claim 11
Dependent Claim
26 words
The optical mass memory of claim 1 wherein the light source means produces the light pulses at a rate of greater than 106 pulses per second.
Claim 12
Dependent Claim
19 words
The optical mass memory of claim 1 wherein the pulses have a duration of greater than about one-tenth nano-second.
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |