USH686H
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electro-optical light modulator for protection of optical systems against pulsed lasers
Assignee: United States Department of the Army
•
Filing: 1988-11-07
•
Granted: 1989-10-03
•
Expires: 2008-11-07
Abstract
Abstract An electro-optic shutter containing liquid crystal material is used to prct optical systems from pulsed laser radiation. The shutter provides the protection by being positioned between the optical system and the pulsed laser radiation and by rapidly alternating between clear and dark states. The alternation occurs in response to the absence or presence of an electric field in the shutter. When the electric field is absent, the shutter becomes clear and admits light and thus visual information whereas presence of the electric field causes the shutter to become dark and prevent the pulsed laser radiation from reaching the optical system. For protection of a binocular system such as the human eyes, in addition to the alternation of clear and dark states of each shutter, the clear-dark cycles of the shutters are staggered to assure that at any given moment at least one optical system is protected.
Inventors
- 👤 William D. Mullins
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 01:00
CPC Classifications
A; A61; A61F; A61F9/00; A61F9/02; A61F9/022; A61F9/023
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
83 words
A device for protecting optical systems from pulsed laser radiation, comprising: an electro-optic shutter for alternating between clear state and dark state to respectively admit or inhibit radiation, a shutter control circuit coupled to drive said shutter to cause said shutter to alternate between the clear and dark states, a housing for containing said control circuit and means for mounting said shutter on an optical system such that said electro-optic shutter is disposed between the optical system to be protected and impinging radiation.
Claim 2
Independent Claim
83 words
A device for protecting optical systems from pulsed laser radiation, comprising: an electro-optic shutter for alternating between clear state and dark state to respectively admit or inhibit radiation, a shutter control circuit coupled to drive said shutter to cause said shutter to alternate between the clear and dark states, a housing for containing said control circuit and means for mounting said shutter on an optical system such that said electro-optic shutter is disposed between the optical system to be protected and impinging radiation.
Claim 3
Dependent Claim
40 words
A device as set forth in claim 1 wherein said electro-optic shutter comprises a liquid crystal layer sandwiched between first and second polarizers, said first and second polarizers having their planes of polarization rotated 90 degrees relative to each other.
Claim 4
Dependent Claim
32 words
A device as set forth in claim 2 wherein said liquid crystal layer, when an electric field is absent therefrom, causes polarization rotation of a portion of said radiation by 90 degrees.
Claim 5
Dependent Claim
33 words
A device as set forth in claim 3 wherein said liquid crystal layer further comprises first and second panels of transparent electrically conductive material and liquid crystal material uniformly sandwiched between said panels.
Claim 6
Dependent Claim
28 words
A device as set forth in claim 4 wherein said liquid crystal layer for providing 90 degrees of polarization rotation is between 5 μm and 1 mm thick.
Claim 7
Dependent Claim
63 words
A device as set forth in claim 5 wherein said shutter control circuit comprises a clock for producing pulses at a set regular frequency, a pulse stretcher coupled between said clock and said shutter for stretching said pulses to control duration of said clear and dark states of said shutter and power source means coupled for driving said clock and said pulse stretcher.
Claim 8
Dependent Claim
21 words
A device as set forth in claim 6 wherein said set regular frequency is selectively between 30 Hz and 100 Hz.
Claim 9
Independent Claim
127 words
A device for protecting optical systems from pulsed laser radiation, comprising: electro-optic shutters for protecting first and second optical systems, said first and second shutters each adapted for alternating between clear and dark states to respectively admit or inhibit radiation, shutter control circuit means coupled to drive said shutters for causing said clear and dark states of said first shutter to be noncoincident with clear and dark states of said second shutter, a housing for housing said control circuit means and means for mounting said device on an optical system such that said first electro-optic shutter is disposed between said first optical system to be protected and impinging radiation, and said second electro-optic shutter is disposed between said second optical system to be protected and impinging radiation.
Claim 10
Independent Claim
127 words
A device for protecting optical systems from pulsed laser radiation, comprising: electro-optic shutters for protecting first and second optical systems, said first and second shutters each adapted for alternating between clear and dark states to respectively admit or inhibit radiation, shutter control circuit means coupled to drive said shutters for causing said clear and dark states of said first shutter to be noncoincident with clear and dark states of said second shutter, a housing for housing said control circuit means and means for mounting said device on an optical system such that said first electro-optic shutter is disposed between said first optical system to be protected and impinging radiation, and said second electro-optic shutter is disposed between said second optical system to be protected and impinging radiation.
Claim 11
Dependent Claim
96 words
A device as set forth in claim 8 wherein said shutter control circuit comprises a clock for producing pulses at a set regular frequency, a first pulse stretcher coupled between said first electro-optic shutter and said clock, a delay circuit, a second pulse stretcher coupled between said second electro-optic shutter and said delay circuit, said delay circuit being further coupled to said clock for delaying said pulse output, said pulse output following an electronic path to said second pulse stretcher to produce non-simultaneous alternation of clear and dark states between said first and second electro-optic shutters.
Claim 12
Dependent Claim
47 words
A device as set forth in claim 9 wherein said first and second electro-optic shutters each comprises a liquid crystal layer sandwiched between a first polarizer and a second polarizer, said first and second polarizers having their planes of polarization rotated 90 degrees relative to each other.
Claim 13
Dependent Claim
32 words
A device as set forth in claim 10 wherein said liquid crystal layer, when an electric field is absent therefrom causes polarization rotation of a portion of said radiation by 90 degrees.
Claim 14
Dependent Claim
33 words
A device as set forth in claim 11 wherein said liquid crystal layer further comprises first and second panels of transparent electrically conductive material and liquid crystal material uniformly sandwiched between said panels.
Claim 15
Dependent Claim
21 words
A device as set forth in claim 12 wherein said set regular frequency is selectively between 30 Hz and 100 Hz.
Claim 16
Dependent Claim
28 words
A device as set forth in claim 13 wherein said liquid crystal layer for providing 90 degrees of polarization rotation is between 5 μm and 1 mm thick.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-10-02 | 1993-04-03 | 1993-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-10-02 | 1997-04-03 | 1997-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-10-02 | 2001-04-03 | 2001-10-03 | $7700.00 | Window Closed / Lapsed |