US4994204A
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Light modulating materials comprising a liquid crystal phase dispersed in a birefringent polymeric phase
Assignee: Kent State University
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Filing: 1989-03-20
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Granted: 1991-02-19
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Expires: 2009-03-20
Abstract
Abstract A haze-free light modulating polymer dispersed liquid crystal (PDLC) material is disclosed which comprises a polymer matrix which is birefringent and possesses anisotropic optical properties similar to those of the dispersed liquid crystal microdroplets such that the PDLC material in its transparent state exhibits a refractive index that is matched for all directions of incident light providing for an optically clear, scatter-free film for all angles of view. Electrooptic light shutters are possible from this material which are transparent in the field OFF-state and opaque in the field ON-state or vice versa, depending upon the microdroplet structure and configuration of the light shutter device.
Inventors
- 👤 Joseph W. Doane
- 👤 John L. West
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:48
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/52; C09K19/04; C09K19/38; C09K19/54; C09K19/542; C09K19/544; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1334; C09K2323/00; G02F1/13347
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
87 words
A light modulating liquid crystal material comprising a liquid crystal phase interspersed with a birefringent, light transmissive polymer, the effective indices of refraction of the liquid crystal phase and the polymer being matched for all directions of incident light so that the material is transparent and haze-free in one of a field-ON state or a field-OFF state, and the effective indices of refraction are mismatched for all directions of incident light so that the material is opaque in the other of the field-ON state or field-OFF state.
Claim 2
Dependent Claim
87 words
A light modulating liquid crystal material comprising a liquid crystal phase interspersed with a birefringent, light transmissive polymer, the effective indices of refraction of the liquid crystal phase and the polymer being matched for all directions of incident light so that the material is transparent and haze-free in one of a field-ON state or a field-OFF state, and the effective indices of refraction are mismatched for all directions of incident light so that the material is opaque in the other of the field-ON state or field-OFF state.
Claim 3
Dependent Claim
70 words
The material of claim 1 wherein the liquid crystal phase has ordinary and extraordinary indices of refraction which are respectively matched to the ordinary and extraordinary indices of refraction of the polymer, the material being transparent and haze-free when the optical axes of the liquid crystal phase and the polymer are aligned and being opaque when the optical axes of the liquid crystal phase and the polymer are not aligned.
Claim 4
Dependent Claim
13 words
The material of claim 1 wherein the polymer is a liquid crystal polymer.
Claim 5
Dependent Claim
11 words
The material of claim 3 wherein the polymer comprises a liquid-crystal-side-group.
Claim 6
Dependent Claim
13 words
The material of claim 1 wherein the polymer comprises a liquid-crystal-side-group polymeric epoxy.
Claim 7
Dependent Claim
15 words
The material of claim 4 wherein at least one of the liquid-crystal-side-groups comprises a cyanobiphenyl.
Claim 8
Dependent Claim
16 words
The material of claim 1 wherein the liquid crystal phase exhibits a frequency dependent dielectric anisotropy.
Claim 9
Dependent Claim
122 words
A light modulating liquid crystal material comprising a first optically birefringent phase dispersed in a second optically birefringent phase, one of said first and second birefringent phases comprising a polymer phase having mesogenic moieties with optical axes aligned relative to a surface of the material, the other of said first and second birefringent phases comprising a liquid crystal phase, and the ordinary and extraordinary indices of refraction of the first and second birefringent phases being matched, whereby the material is transparent and haze-free at all viewing angles when the optical axes of the liquid crystal phase and the mesogenic moieties are aligned, and the material is opaque when the optical axes of the liquid crystal phase and the mesogenic moieties are unaligned.
Claim 10
Dependent Claim
122 words
A light modulating liquid crystal material comprising a first optically birefringent phase dispersed in a second optically birefringent phase, one of said first and second birefringent phases comprising a polymer phase having mesogenic moieties with optical axes aligned relative to a surface of the material, the other of said first and second birefringent phases comprising a liquid crystal phase, and the ordinary and extraordinary indices of refraction of the first and second birefringent phases being matched, whereby the material is transparent and haze-free at all viewing angles when the optical axes of the liquid crystal phase and the mesogenic moieties are aligned, and the material is opaque when the optical axes of the liquid crystal phase and the mesogenic moieties are unaligned.
Claim 11
Dependent Claim
27 words
The material of claim 8 wherein the second birefringent phase consists essentially of a liquid-crystal-side-group polymer and the first birefringent phase consists essentially of a liquid crystal.
Claim 12
Dependent Claim
24 words
The material of claim 9 wherein the liquid-crystal-side-group polymer comprises liquid-crystal-side-groups having a labile moiety capable of cross-linking with another moiety identical to itself.
Claim 13
Dependent Claim
15 words
The material of claim 10 wherein the moieties are cross-linked to permanently align the liquid-crystal-side-groups.
Claim 14
Dependent Claim
95 words
A fail-safe, light modulating liquid crystal material comprising microdroplets of liquid crystal exhibiting negative dielectric anisotropy dispersed in a light transmissive, liquid-crystal-side-group polymeric synthetic resin matrix, the ordinary and extraordinary indices of refraction of the microdroplets being respectively matched to the ordinary and extraordinary refractive indices of the matrix, the liquid-crystal-side-groups exhibiting positive dielectric anisotropy, and the optical axes of the matrix and microdroplets being perpendicular to a viewing surface of the material, whereby the material is transparent in the absence of an applied field and is opaque in the presence of an applied field.
Claim 15
Dependent Claim
95 words
A fail-safe, light modulating liquid crystal material comprising microdroplets of liquid crystal exhibiting negative dielectric anisotropy dispersed in a light transmissive, liquid-crystal-side-group polymeric synthetic resin matrix, the ordinary and extraordinary indices of refraction of the microdroplets being respectively matched to the ordinary and extraordinary refractive indices of the matrix, the liquid-crystal-side-groups exhibiting positive dielectric anisotropy, and the optical axes of the matrix and microdroplets being perpendicular to a viewing surface of the material, whereby the material is transparent in the absence of an applied field and is opaque in the presence of an applied field.
Claim 16
Dependent Claim
87 words
A fail-safe, light modulating liquid crystal material comprising a light transmissive, liquid crystal polymeric synthetic resin matrix containing microdroplets of liquid crystal, the ordinary and extraordinary indices of refraction of the microdroplets and the matrix being respectively matched, and the optical axes of the microdroplets and matrix being aligned parallel in a direction oblique to the viewing angle of incident light, and the microdroplets being responsive to an applied field to misalign the optical axes of the microdroplets and whereby the material is opaque in the ON-state.
Claim 17
Dependent Claim
87 words
A fail-safe, light modulating liquid crystal material comprising a light transmissive, liquid crystal polymeric synthetic resin matrix containing microdroplets of liquid crystal, the ordinary and extraordinary indices of refraction of the microdroplets and the matrix being respectively matched, and the optical axes of the microdroplets and matrix being aligned parallel in a direction oblique to the viewing angle of incident light, and the microdroplets being responsive to an applied field to misalign the optical axes of the microdroplets and whereby the material is opaque in the ON-state.
Claim 18
Dependent Claim
61 words
A light modulating liquid crystal material comprising discrete quantities of liquid crystal contained in a birefringent solid, the discrete quantities of liquid crystal having ordinary and extraordinary indices of refraction which are respectively matched to ordinary and extraordinary indices of refraction of the matrix so that the material is light-transmissive when the optical axes of the microdroplets and matrix are aligned.
Claim 19
Dependent Claim
61 words
A light modulating liquid crystal material comprising discrete quantities of liquid crystal contained in a birefringent solid, the discrete quantities of liquid crystal having ordinary and extraordinary indices of refraction which are respectively matched to ordinary and extraordinary indices of refraction of the matrix so that the material is light-transmissive when the optical axes of the microdroplets and matrix are aligned.
Claim 20
Dependent Claim
28 words
A material according to claim 1 wherein the polymer comprises a polymer matrix and the liquid crystal phase comprises microdroplets of liquid crystal dispersed in the polymer matrix.
Claim 21
Dependent Claim
25 words
A material according to claim 8 wherein the first birefringent phase is the liquid crystal phase and the second birefringent phase is the polymer phase.
Claim 22
Dependent Claim
165 words
A light modulating liquid crystal material comprising a first optically birefringent phase dispersed in a second optically birefringent phase, one of said first and second birefringent phases comprising a polymer phase having mesogenic moieties and the other of said first and second birefringent phases comprising a liquid crystal phase; ordinary and extraordinary indices of refraction of the liquid crystal phase and the mesogenic moieties being matched; optical axes of the liquid crystal phase and the mesogenic moieties being aligned in the absence of an electric or magnetic field so that the effective indices of refraction of the liquid crystal phase and the mesogenic moieties for all directions of incident light are matched; and said liquid crystal phase being responsive to an applied electric or magnetic field to reorient the optical axis of the liquid crystal out of alignment with the optical axis of the liquid crystalline polymer phase so that the material is less light transmissive in a field-on state than in a field-off state.
Claim 23
Dependent Claim
165 words
A light modulating liquid crystal material comprising a first optically birefringent phase dispersed in a second optically birefringent phase, one of said first and second birefringent phases comprising a polymer phase having mesogenic moieties and the other of said first and second birefringent phases comprising a liquid crystal phase; ordinary and extraordinary indices of refraction of the liquid crystal phase and the mesogenic moieties being matched; optical axes of the liquid crystal phase and the mesogenic moieties being aligned in the absence of an electric or magnetic field so that the effective indices of refraction of the liquid crystal phase and the mesogenic moieties for all directions of incident light are matched; and said liquid crystal phase being responsive to an applied electric or magnetic field to reorient the optical axis of the liquid crystal out of alignment with the optical axis of the liquid crystalline polymer phase so that the material is less light transmissive in a field-on state than in a field-off state.
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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) | 1994-02-18 | 1994-08-20 | 1995-02-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-02-18 | 1998-08-20 | 1999-02-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-02-18 | 2002-08-20 | 2003-02-19 | $7700.00 | Window Closed / Lapsed |