US5430563A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for obtaining composite materials based on polymers and liquid crystals with dichroic dyes
Assignee: Thales SA
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Filing: 1994-02-23
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Granted: 1995-07-04
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Expires: 2014-02-23
Abstract
Abstract Disclosed is an original method for preparing composite materials for a display screen, these materials containing a polymer, liquid crystal and dye. The present problem is one of inserting molecules of dye into composites of this type. The disclosed method proposes the preparation, in a first step, of a porous film of reticulate polymer. Then, molecules of liquid crystal (XL) and molecules of dye (C) are made to diffuse therein by a polymer-expanding solvent. After evaporation of the solvent, a film of polymer is obtained with inclusions containing liquid crystal (XL) and dye (C) with a wide range of concentrations in liquid crystal, thus making it possible to optimize the performance characteristics in terms of contrast and control voltage of the screen thus made.
Inventors
- 👤 Laurent Bouteiller
- 👤 Pierre Le Barny
- 👤 Jean-Pierre Vairon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:59
CPC Classifications
C; C09; C09K; C09K19/00; C09K19/52; C09K19/54; C09K19/542; C09K19/544; G; G02; G02F; G02F1/00; G02F1/01; G02F1/13; G02F1/133; G02F1/1333; G02F1/1334
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
100 words
A method to obtain composite material for a display screen, comprising a polymer (P), molecules of liquid crystal (XL) and molecules of dichroic dyes (C) wherein said method comprises the following steps: the making of a porous film (F) of reticulate polymer on a substrate (S); the diffusion, in the porous film (F), of a mixture (M) containing a solvent (L) capable of expanding the polymer, molecules of liquid crystal (XL) and molecules of dichroic dye; the evaporation of the solvent, leading to the obtaining of a polymer film with inclusions comprising a mixture of liquid crystal and dichroic dye.
Claim 2
Independent Claim
100 words
A method to obtain composite material for a display screen, comprising a polymer (P), molecules of liquid crystal (XL) and molecules of dichroic dyes (C) wherein said method comprises the following steps: the making of a porous film (F) of reticulate polymer on a substrate (S); the diffusion, in the porous film (F), of a mixture (M) containing a solvent (L) capable of expanding the polymer, molecules of liquid crystal (XL) and molecules of dichroic dye; the evaporation of the solvent, leading to the obtaining of a polymer film with inclusions comprising a mixture of liquid crystal and dichroic dye.
Claim 3
Dependent Claim
38 words
A method for obtaining composite material for a display screen according to claim 1, wherein the porous film of reticulate polymer is obtained from a mixture (M) o of photopolymerizable monomer, photoinitiator and liquid crystal (XL) o .
Claim 4
Dependent Claim
29 words
A method for obtaining composite material for a display screen according to claim 2, wherein the monomer is polyfunctional to form a network of reticulate polymer during the polymerization.
Claim 5
Independent Claim
53 words
A method for obtaining composite material for a display screen according to either of the claims 2 or 3, wherein the mixture (M) o is introduced by capillarity into a dismountable cell having a substrate (S) and a second substrate (S) o with low surface energy, separated from the substrate (S) by shims.
Claim 6
Dependent Claim
28 words
A method for obtaining composite material for a display screen according to claim 4, wherein the photopolymerization is achieved by ultraviolet irradiation through the substrate (S) o .
Claim 7
Dependent Claim
64 words
A method for obtaining composite material for a display screen according to claim 5 wherein, after the polymerization, the substrate (S) o is removed and the porous film of reticulate polymer containing inclusions of liquid crystal (XL) o is washed with a solvent (L) o so as to eliminate the traces of monomer and initiator as well as the liquid crystal (XL) o .
Claim 8
Dependent Claim
25 words
A method for obtaining composite material for a screen according to claim 6, wherein the mixture (M) is introduced into the porous film of polymer.
Claim 9
Dependent Claim
25 words
A method for obtaining composite material for a display screen according to claim 6, wherein the solvent (L) o is identical to the solvent (L).
Claim 10
Dependent Claim
19 words
A method for obtaining composite material according to claim 8, wherein the photopolymerizable monomer is of the acrylic type.
Claim 11
Dependent Claim
20 words
A method for obtaining composite material for a display screen according to claim 9 wherein the solvent (L) is dichloromethane.
Claim 12
Dependent Claim
16 words
A method for obtaining composite material according to claim 9, wherein the solvent (L) is hexane.
Claim 13
Dependent Claim
41 words
A method for obtaining composite material for a display screen according to claim 2, wherein the liquid crystal (XL) o used to create the porosity of the film is the same as the liquid crystal (XL) of the final composite material.
Claim 14
Dependent Claim
19 words
A method for obtaining composite material according to claim 12, wherein the photopolymerizable monomer is of the acrylic type.
Claim 15
Dependent Claim
60 words
A method for obtaining composite material for a display screen according to claim 1, wherein the porous film (F) of reticulate polymer is obtained from a mixture (M)' o of monomer, a liquid that is a solvent of monomer and not a solvent of polymer formed out of the polymer, said liquid having a low surface tension at ambient temperature.
Claim 16
Dependent Claim
39 words
A method for obtaining composite material for a display screen according to claim 1, wherein the step for the evaporation of the solvent (L) is followed by a second step of vacuum-drying to eliminate the remaining traces of solvent.
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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) | 1998-07-03 | 1999-01-02 | 1999-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-03 | 2003-01-02 | 2003-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-03 | 2007-01-02 | 2007-07-04 | $7700.00 | Window Closed / Lapsed |