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US5530566A
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Polymer dispersed ferroelectric smectic liquid crystal formed by inducing a force during phase separation
Assignee: Kent State University
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Filing: 1994-02-25
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Granted: 1996-06-25
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Expires: 2014-02-25
Abstract
Abstract Disclosed is a class of light modulating materials comprising microdomains of ferroelectric smectic liquid crystal dispersed in a light-transmissive polymer medium. The microdomains are formed by phase separation of the liquid crystal from solution with the polymer as the polymer is solidified. The switching of the liquid crystal may be either monostable or multistable (e.g., bistable), depending on the liquid crystal and polymer. The material modulates light in either a scattering-transmissive mode or a birefringence mode. Materials operating in the scattering-transmissive mode do not require polarizers, Advantages of the materials include switching times down to the order of microseconds or less, multistable optical states, wide viewing angles and high contrast.
Inventors
- 👤 Satyendra Kumar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:58
CPC Classifications
G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/137; G02F1/139; G02F1/141; C; C09; C09K; C09K19/00; C09K19/02; C09K19/0225; C09K19/52; C09K19/54; C09K19/542; C09K19/544; G02F1/133; G02F1/1333; G02F1/1334
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
93 words
A method for forming a light modulating material comprising the steps of: a) forming a solution having a mesogenic component capable of forming a ferroelectric smectic liquid crystal phase and a medium-forming component capable of forming a light transmissive polymer medium; b) inducing a force in the solution to promote alignment of molecules of the mesogenic component along a direction relative to a surface of the solution; and c) solidifying the medium-forming component while the force is induced to promote phase separation of microdomains of the ferro-electric smectic phase from the polymeric medium.
Claim 2
Independent Claim
93 words
A method for forming a light modulating material comprising the steps of: a) forming a solution having a mesogenic component capable of forming a ferroelectric smectic liquid crystal phase and a medium-forming component capable of forming a light transmissive polymer medium; b) inducing a force in the solution to promote alignment of molecules of the mesogenic component along a direction relative to a surface of the solution; and c) solidifying the medium-forming component while the force is induced to promote phase separation of microdomains of the ferro-electric smectic phase from the polymeric medium.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein the step of inducing a force in the solution is performed by imposing an electromagnetic field in the solution while the medium-forming component is being solidified.
Claim 4
Dependent Claim
30 words
The method of claim 2 wherein the step of imposing an electromagnetic field includes imposing an electromagnetic field having a electric field component perpendicular to the surface of the solution.
Claim 5
Dependent Claim
30 words
The method of claim 2 wherein the step of imposing an electromagnetic field includes imposing an electromagnetic field having a magnetic field component parallel to the surface of the solution.
Claim 6
Dependent Claim
69 words
The method of claim 4 wherein the step of imposing an electromagnetic field includes imposing an electromagnetic field having a magnetic field component parallel to the surface of the solution and a DC electric field component perpendicular to the surface; and wherein the method includes the additional steps of positioning optical polarizers adjacent the material and adjusting the polarization directions of the polarizers to maximize or minimize light transmission.
Claim 7
Dependent Claim
40 words
A method according to claim 1 wherein the step of inducing a force in the solution is performed by imposing a thermal gradient along a direction parallel to the surface of the solution while the medium-forming component is being solidified.
Claim 8
Dependent Claim
29 words
A method according to claim 1 wherein said step of inducing said force is performed by shearing said material to promote elongation of droplets of the ferroelectric smectic phase.
Claim 9
Dependent Claim
17 words
A method according to claim 7 wherein the mesogenic material is selected to have positive dielectric anisotropy.
Claim 10
Dependent Claim
36 words
A method according to claim 7 wherein the step of shearing the material is performed while heating the material to a temperature in which the liquid crystal is in the smectic A or smectic C phase.
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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) | 1999-06-25 | 1999-12-25 | 2000-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-25 | 2003-12-25 | 2004-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-25 | 2007-12-25 | 2008-06-25 | $7700.00 | Window Closed / Lapsed |