Patent US3720926A successfully refreshed from Google Patents.
US3720926A
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Information storage using m color centers in alkali fluorides
Assignee: Individual
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Filing: 1971-03-31
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Granted: 1973-03-13
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Expires: 1991-03-31
Abstract
Abstract Anisotropic color centers, such as M and MA centers in alkali fluoride crystals such as sodium fluoride (NaF), are used for the storage of information. Polarized optical irradiation is used to align the color centers along discrete crystallographic directions. Reorientation of a center can occur whenever the incident irradiation is of proper wavelength and is absorbed by the center. An information state is related to the particular orientation of the color centers and is subsequently read-out by detecting and interpreting the degree of absorption of incident polarized optical radiation thereon or its induced polarized emission. Unlike other materials for which this technique is applied, the operational temperature of the NaF is much higher (above 200*K) than has ever previously been required.
Inventors
- 👤 I Schneider
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:01
CPC Classifications
G; G11; G11C; G11C11/00; G11C13/00; G11C13/04
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
115 words
An optical information storage and retrieval system comprising: an optical material having MA centers capable of being aligned in a common direction at temperatures above 200*K; first irradiating means including polarized radiation operatively associated with said material to align substantially all said Ma centers in a common direction; second irradiation means including polarized radiation of different polarity from said first irradiating means operatively associated with said material to reorient said MA centers in predetermined portions of said optical material whereby information is written into said optical material; and detection means including third irradiating means operatively associated with said material for determining the information state thereof; wherein the improvement comprises alkali fluoride as said optical material.
Claim 2
Dependent Claim
115 words
An optical information storage and retrieval system comprising: an optical material having MA centers capable of being aligned in a common direction at temperatures above 200*K; first irradiating means including polarized radiation operatively associated with said material to align substantially all said Ma centers in a common direction; second irradiation means including polarized radiation of different polarity from said first irradiating means operatively associated with said material to reorient said MA centers in predetermined portions of said optical material whereby information is written into said optical material; and detection means including third irradiating means operatively associated with said material for determining the information state thereof; wherein the improvement comprises alkali fluoride as said optical material.
Claim 3
Dependent Claim
12 words
The system of claim 1 wherein said alkali fluoride is sodium fluoride.
Claim 4
Dependent Claim
12 words
The system of claim 1 wherein said alkali fluoride is lithium fluoride.
Claim 5
Dependent Claim
98 words
An optical memory system utilizing the anisotropic properties of color centers within an alkali halide memory element for representing information states comprising: a memory element comprising an alkali fluoride having MA centers dispersed therein which can be reoriented at temperatures above 200*K; optical excitation means directed toward predetermined portions of said element including a first polarized irradiation means for orienting selected MA centers to represent stored information and for removing said information; a second polarized irradiation means for interrogating said selected MA centers; and, detection means operatively associated with said memory element for determining the information state thereof.
Claim 6
Dependent Claim
98 words
An optical memory system utilizing the anisotropic properties of color centers within an alkali halide memory element for representing information states comprising: a memory element comprising an alkali fluoride having MA centers dispersed therein which can be reoriented at temperatures above 200*K; optical excitation means directed toward predetermined portions of said element including a first polarized irradiation means for orienting selected MA centers to represent stored information and for removing said information; a second polarized irradiation means for interrogating said selected MA centers; and, detection means operatively associated with said memory element for determining the information state thereof.
Claim 7
Dependent Claim
12 words
The system of claim 4 wherein said alkali fluoride is sodium fluoride.
Claim 8
Dependent Claim
12 words
The system of claim 4 wherein said alkali fluoride is lithium fluoride.
Claim 9
Dependent Claim
24 words
An alkali fluoride memory element containing MA centers dispersed therein which are oriented at temperatures above 200*K along predetermined directions to represent stored information.
Claim 10
Dependent Claim
24 words
An alkali fluoride memory element containing MA centers dispersed therein which are oriented at temperatures above 200*K along predetermined directions to represent stored information.
Claim 11
Dependent Claim
13 words
The memory element of claim 7 wherein said alkali fluoride is lithium fluoride.
Claim 12
Dependent Claim
13 words
The memory element of claim 7 wherein said alkali fluoride is sodium fluoride.
Claim 13
Dependent Claim
14 words
The sodium fluoride memory element of claim 9 which has been doped with Na2O2.
Claim 14
Dependent Claim
14 words
The sodium fluoride memory element of claim 9 which has been doped with LiF.
Claim 15
Independent Claim
71 words
A method of storing and retrieving information at temperatures above 200*K including room temperature comprising the steps of: establishing particular orientations of MA centers in at least portions of an alkali fluoride crystal with a first optical radiation at a temperature between 200*K and room temperature; and determining the orientation of said MA centers by irradiating said portions of said crystal with a second optical radiation and measuring the transmission therefrom.
Claim 16
Independent Claim
71 words
A method of storing and retrieving information at temperatures above 200*K including room temperature comprising the steps of: establishing particular orientations of MA centers in at least portions of an alkali fluoride crystal with a first optical radiation at a temperature between 200*K and room temperature; and determining the orientation of said MA centers by irradiating said portions of said crystal with a second optical radiation and measuring the transmission therefrom.
Claim 17
Dependent Claim
12 words
The method of claim 12 wherein said alkali fluoride is sodium fluoride.
Claim 18
Dependent Claim
14 words
The method of claim 12 wherein said steps are carried out at room temperature.
Claim 19
Dependent Claim
12 words
The method of claim 12 wherein said alkali fluoride is lithium fluoride.
Claim 20
Dependent Claim
14 words
The method of claim 12 wherein said first and second radiations are linearly polarized.
References Cited (Backward Citations)
US3466616A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-12 | 1976-09-11 | 1977-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-12 | 1980-09-11 | 1981-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-12 | 1984-09-11 | 1985-03-13 | $7700.00 | Window Closed / Lapsed |