US3701121A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fine grain ferroelectric ceramic optical display device utilizing thermal depoling write-in
Assignee: AT&T Inc
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Filing: 1970-04-22
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Granted: 1972-10-24
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Expires: 1990-04-22
Abstract
Abstract An optical display device includes a fine grain polycrystalline ferroelectric ceramic plate, which is located between an optical polarizer and an analyzer. The ferroelectric plate is ''''reset'''' by means of an applied electric field, which electrically polarizes the entire plate. Then, the plate is subjected to a ''''write-in'''' by means of an intensity modulated scanning electron (or laser) beam, which locally heats and thereby selectively depolarizes portions of the plate. The plate is then subjected to a ''''readout'''' beam of light, which is selectively transmitted through the device at those portions of the plate which have been exposed to maximum intensity of the ''''write-in'''' beam.
Inventors
- 👤 David Bruce Fraser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:52
CPC Classifications
G; G11; G11C; G11C13/00; G11C13/04; G11C13/047
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
17 words
A device according to claim 1 in which the plate is essentially lanthanum doped lead zirconate-lead titanate.
Claim 2
Dependent Claim
23 words
A device according to claim 1 which further includes an optical polarizer and an optical analyzer positioned on opposite sides of the plate.
Claim 3
Dependent Claim
31 words
A device according to claim 1 which further includes a pair of interdigitated electrodes disposed on a major surface of the plate, the voltage means being electrically connected to said electrodes.
Claim 4
Dependent Claim
19 words
The device recited in claim 1 in which the write-in beam is an intensity modulated scanning beam of electrons.
Claim 5
Dependent Claim
49 words
The device recited in claim 1 in which the means for forming the write-in beam is a laser, and which further includes a filter located on the side of the plate away from the laser, the filter being adapted to absorb the write-in beam after transmission through the plate.
Claim 6
Dependent Claim
26 words
An optical image storage and display system which comprises: a. the device recited in claim 1; and b. means for forming the readout beam of liGht.
Claim 7
Dependent Claim
17 words
The system recited in claim 7 in which the plate is essentially lanthanum doped lead zirconate-lead titanate.
Claim 8
Dependent Claim
47 words
An optical image storage and display system which comprises: a. the device recited in claim 5; b. an intensity modulated electron gun, in order to supply the write-in beam; and c. means for deflecting and directing the write-in beam onto the plate in accordance with the pattern.
Claim 9
Dependent Claim
18 words
The system recited in claim 9 in which the plate is essentially lead zirconate-lead titanate doped with lanthanum.
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) | 1975-10-24 | 1976-04-24 | 1976-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-24 | 1980-04-24 | 1980-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-24 | 1984-04-24 | 1984-10-24 | $7700.00 | Window Closed / Lapsed |