US3661442A
Expired / Lapsed
US
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Electrically operated optical shutter
Assignee: Hitachi Ltd
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Filing: 1970-03-17
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Granted: 1972-05-09
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Expires: 1990-03-17
Abstract
Abstract An optical shutter comprising a pair of crossed polarizing means, and at least one double-refractive crystal and at least one Z-cut irregular ferroelectric crystal both interposed between the pair of crossed polarizing means, the said crystal having equal retardations, the value of the resulting retardation R of the crystals in the open position of the shutter being 80 </= R </= 320 or R >/= 2000, whereby a field at least equal to the magnitude of the coercive field Ec of the irregular ferroelectric crystal or a stress at least equal to the magnitude of the coercive stress Tc of the irregular ferroelectric crystal is applied to the same crystal to rotate the optic axial plane thereof by 90 DEG to pass or stop the natural light transmitted through the shutter as desired.
Inventors
- 👤 Akio Kumada
- 👤 Massashi Koga
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:18
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/03; G02F1/05
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
141 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelastic-ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refractive light passing through said double-refractive crystal plate is equal to the retardation of double-refractive light passing through said Z-cut irregular ferroelastic-ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter satisfies one of the relationships 80 < OR = R < OR = 320, 2,000 < OR = R, and means provided on said irregular ferroelastic-ferroelectric crystal plate for applying thereto a field or stress at least equal to the magnitude of the coercive field or stress, respectively, of that crystal plate.
Claim 2
Dependent Claim
141 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelastic-ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refractive light passing through said double-refractive crystal plate is equal to the retardation of double-refractive light passing through said Z-cut irregular ferroelastic-ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter satisfies one of the relationships 80 < OR = R < OR = 320, 2,000 < OR = R, and means provided on said irregular ferroelastic-ferroelectric crystal plate for applying thereto a field or stress at least equal to the magnitude of the coercive field or stress, respectively, of that crystal plate.
Claim 3
Dependent Claim
16 words
An optical shutter as defined in claim 1, wherein said irregular ferroelastic-ferroelectric crystal is gadolinium molybdate.
Claim 4
Dependent Claim
141 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one plate of double-refractive material plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said plate of double-refractive material is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes 80 < or = R < or = 320, a transparent electrode provided in the Z-cut plane of said irregular ferroelectric crystal, and electric means for applying through said transparent electrode a field at least equal to the magnitude of the coercive field of said irregular ferroelectric crystal.
Claim 5
Dependent Claim
141 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one plate of double-refractive material plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said plate of double-refractive material is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes 80 < or = R < or = 320, a transparent electrode provided in the Z-cut plane of said irregular ferroelectric crystal, and electric means for applying through said transparent electrode a field at least equal to the magnitude of the coercive field of said irregular ferroelectric crystal.
Claim 6
Dependent Claim
16 words
An optical shutter as defined in claim 3, wherein said irregular ferroelectric crystal is gadolinium molybdate.
Claim 7
Dependent Claim
16 words
An optical shutter as defined in claim 4, wherein said transparent electrode is formed of SnO2.
Claim 8
Dependent Claim
134 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive material plate both interposed between said pair of polariZing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said double-refractive material plate is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes R > or = 2000, a transparent electrode provided in the Z-cut plane of said irregular ferroelectric crystal, and electric means for applying through said transparent electrode a field at least equal to the magnitude of the coercive field of said irregular ferroelectric crystal.
Claim 9
Dependent Claim
134 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive material plate both interposed between said pair of polariZing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said double-refractive material plate is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes R > or = 2000, a transparent electrode provided in the Z-cut plane of said irregular ferroelectric crystal, and electric means for applying through said transparent electrode a field at least equal to the magnitude of the coercive field of said irregular ferroelectric crystal.
Claim 10
Dependent Claim
16 words
An optical shutter as defined in claim 6, wherein said irregular ferroelectric crystal is gadolinium molybdate.
Claim 11
Dependent Claim
18 words
An optical shutter as defined in claim 7, wherein said transparent electrode is formed of SnO2 or InO2.
Claim 12
Dependent Claim
144 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected such that the retardation of double-refracted light passing through said double-refractive crystal plate is equal to the retardation of the double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes 80 < or = R < or = 320, and pressure means are provided to said irregular ferroelectric crystal plate for applying thereto a stress at least equal in magnitude to the coercive stress of that crystal plate by means of pressing elements movable along the X- and Y-axes of said crystal plate.
Claim 13
Dependent Claim
144 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected such that the retardation of double-refracted light passing through said double-refractive crystal plate is equal to the retardation of the double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes 80 < or = R < or = 320, and pressure means are provided to said irregular ferroelectric crystal plate for applying thereto a stress at least equal in magnitude to the coercive stress of that crystal plate by means of pressing elements movable along the X- and Y-axes of said crystal plate.
Claim 14
Dependent Claim
16 words
An optical shutter as defined in claim 9, wherein said irregular ferroelectric crystal is gadolinium molybdate.
Claim 15
Dependent Claim
139 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said double-refractive crystal plate is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes R > or = 2000, and pressure means provided to said irregular ferroelectric crystal plate for applying thereto a stress at least equal to the magnitude of the coercive stress of that crystal plate by means of pressing elements movable along the X- and Y-axes of said crystal plate.
Claim 16
Dependent Claim
139 words
An optical shutter comprising a pair of crossed polarizing means, at least one Z-cut irregular ferroelectric crystal plate and at least one double-refractive crystal plate both interposed between said pair of polarizing means, said crystal plates having a thickness selected so that the retardation of double-refracted light passing through said double-refractive crystal plate is equal to the retardation of double-refracted light passing through said Z-cut irregular ferroelectric crystal plate and that the value of the resulting retardation R of said crystal plates in the open position of said shutter becomes R > or = 2000, and pressure means provided to said irregular ferroelectric crystal plate for applying thereto a stress at least equal to the magnitude of the coercive stress of that crystal plate by means of pressing elements movable along the X- and Y-axes of said crystal plate.
Claim 17
Dependent Claim
16 words
An optical shutter as defined in claim 11, wherein said irregular ferroelectric crystal is gadolinium molybdate.
References Cited (Backward Citations)
US2680146A
Cited
US3559185A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |