US3573449A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical pulse expansion system
Assignee: Unisys Corp
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Filing: 1968-10-21
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Granted: 1971-04-06
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Expires: 1988-10-21
Abstract
Abstract An optical pulse expansion device includes first and second ultrasonic light modulators and a coded mask positioned so that a collimated light beam can be passed serially through these elements and focused on a photodetector. The first ultrasonic light modulator is sandwiched between crossed polarizers that block the passage of light under quiescent conditions. First acoustic pulses are propagated through the first ultrasonic light modulator in synchronism with second acoustical pulses that are propagated through the second ultrasonic light modulator. These pulses limit the light to the acoustically stressed regions of the second ultrasonic light modulator when scanning the coded mask.
Inventors
- 👤 William T Maloney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:37
CPC Classifications
G; G06; G06E; G06E3/00; G06E3/001; G02; G02F; G02F1/00; G02F1/01; G02F1/11
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
156 words
A pulse expansion device comprisIng means to produce a collimated light beam; an ultrasonic scanner; a first ultrasonic light modulator in said scanner; a second ultrasonic light modulator; a coded mask; said scanner, said second light modulator and said coded mask being arranged serially in the path of said collimated light beam; said coded mask being placed in an amplitude plane of the Fresnel zone of the second light modulator; said scanner being arranged to pass light only in an area stressed by the acoustic wave; said first light modulator and said second light modulator being constructed to propagate acoustic waves at the same velocity and arranged to propagate acoustic waves in the same in the same direction across said light beam; means for simultaneously launching acoustic waves in both of said light modulators; and detection means to produce an electrical signal indicative of the instantaneous value of the total light passing through said coded mask.
Claim 2
Dependent Claim
156 words
A pulse expansion device comprisIng means to produce a collimated light beam; an ultrasonic scanner; a first ultrasonic light modulator in said scanner; a second ultrasonic light modulator; a coded mask; said scanner, said second light modulator and said coded mask being arranged serially in the path of said collimated light beam; said coded mask being placed in an amplitude plane of the Fresnel zone of the second light modulator; said scanner being arranged to pass light only in an area stressed by the acoustic wave; said first light modulator and said second light modulator being constructed to propagate acoustic waves at the same velocity and arranged to propagate acoustic waves in the same in the same direction across said light beam; means for simultaneously launching acoustic waves in both of said light modulators; and detection means to produce an electrical signal indicative of the instantaneous value of the total light passing through said coded mask.
Claim 3
Dependent Claim
58 words
The apparatus of claim 1 in which said ultrasonic scanner includes first and second light polarizing means arranged on opposite sides of the first ultrasonic light modulator; said first and second polarizing means being arranged so that their axes of polarization are parallel to and perpendicular to the acoustic propagation axis of the first ultrasonic light modulator respectively.
Claim 4
Dependent Claim
50 words
The apparatus of claim 2 in which the acoustic wave launching means provides burst of energy at a radiofrequency and in which the highest frequency of the acoustic wave launched in the first modulator is less than one-third the lowest frequency of the acoustic wave launched in the second modulator.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |