Xin H Chen

US Patent:

6569504, May 27, 2003

Filed:

Aug 11, 2000

Appl. No.:

09/639500

Inventors:

David M. Walba - Boulder CO
Daniel J. Dyer - Pasadena CA
Uwe Muller - Berlin, DE
Peter Cobben - Waalre, NL
Xin Hua Chen - Boulder CO
William Thurmes - Longmont CO
Michael Wand - Boulder CO

Assignee:

Displaytech, Inc. - Longmont CO

International Classification:

C09K 1952

US Classification:

428 11, 25229901, 2522992, 2522996, 25229963, 25229961

Abstract:

This invention provides LC compositions useful as birefringent materials in electrooptic devices which exhibit zero or low negatively sloped birefringence dispersioon (e. g. , exhibiting positive birefringence dispersion significantly lower than that of currently available LC compositions) or more preferably positively sloped birefringence dispersion in which birefringence of the material increases with wavelength. The invention provides compounds useful as components of LC compositions which exhibit negative birefringence where n is higher than n. The compounds of this invention are dimers of LC-like compounds in which the monomers are linked to each other through a high birefringence moiety (dimerization linker). The LC monomers consist of an LC core and one or two tail groups. Preferred monomers for this invention have low birefringence in comparison to the birefringence of the monomer linking moiety.

US Patent:

6838128, Jan 4, 2005

Filed:

Feb 5, 2002

Appl. No.:

10/068557

Inventors:

Michael Wand - Boulder CO, US
Xin Hua Chen - Erie CO, US

Assignee:

Displaytech, Inc. - Longmont CO

International Classification:

C09K 1934
C09K 1942
C07D30756
C07D23924
C07D40502

US Classification:

428 11, 25229901, 25229961, 25229962, 25229963, 25229966, 25229967, 544329, 544333, 546268, 546283, 549313, 549318, 549319

Abstract:

The invention relates to chiral nonracemic liquid crystal compounds which are useful as components in liquid crystal compositions to impart high polarization to the mixture. The materials of this invention can be combined with liquid crystal host materials to impart improved properties to mixtures. Chiral nonracemic compounds of this invention can function as additives or dopants in host materials to impart chirality into an LC material. Most generally the invention provides mixtures containing one or more chiral nonracemic dopants which have a chiral nonracemic tail that is an optionally substituted α-ester γ-lactone of the formula: where * indicates a chiral carbon; Ris a straight-chain or branched alkyl or alkenyl group wherein one or more non-neighboring carbon atoms can be replaced with an oxygen atom and wherein one or more carbons can be substituted with one or more halogens; Rand R, independently of one another, can be hydrogen, a halogen or a lower alkyl or alkenyl group; and X is hydrogen or a lower alkyl group. LC compounds having a chiral nonracemic tail of this general formula have large dipoles (and large spontaneous polarization (P)) and when doped into hosts such as achiral smectic C FLC hosts, lead to improved switching speeds of the FLC materials.

US Patent:

7083832, Aug 1, 2006

Filed:

May 11, 2001

Appl. No.:

09/854181

Inventors:

Michael Wand - Boulder CO, US
Neil Gough - Longmont CO, US
Xin Hua Chen - Erie CO, US

Assignee:

Displaytech, Inc. - Longmont CO

International Classification:

C09K 19/20
C09K 19/34
C07C 69/76
C07C 25/13
C07D 239/02

US Classification:

428 11, 25229961, 25229964, 25229965, 560 65, 560 83, 560 85, 570127, 570129, 544303, 544334

Abstract:

The invention provides LC compositions that exhibit V-shaped switching when aligned in an analog device configuration and exhibit bistability when aligned in a bookshelf-type device configuration. The invention more specifically provides LC compositions of formula 1 and particularly chiral nonracemic compounds of formula 1 which exhibit bistable switching as well as V-shaped switching when aligned in appropriate device configurations. The invention also provides methods of using the compounds of the invention in making LC compositions and electooptical devices comprising an aligned layer of the compositions of this invention.

US Patent:

7195719, Mar 27, 2007

Filed:

Jan 3, 2002

Appl. No.:

10/038054

Inventors:

Michael Wand - Boulder CO, US
Xin Hua Chen - Erie CO, US
William N. Thurmes - Longmont CO, US

Assignee:

Displaytech, Inc. - Longmont CO

International Classification:

C09K 19/34
C09K 19/30
C09K 19/12
C09K 19/20
C07D 303/08

US Classification:

25229961, 252 9963, 25229966, 25229967, 544242, 544298, 544335, 549324, 549455, 549563

Abstract:

The invention relates to chiral nonracemic liquid crystal compounds having achiral tails comprising a perfluoroalkyl terminal portion which are useful as components in liquid crystal to impart high polarization to the mixture. The materials of this invention can be combined with known liquid crystal host materials to impart improved properties. Chiral nonracemic compounds of this invention can function as additives or dopants in host materials to impart chirality into an LC material.

US Patent:

20030003245, Jan 2, 2003

Filed:

Jan 3, 2001

Appl. No.:

09/753749

Inventors:

Neil Gough - Longmont CO, US
Xin Chen - Erie CO, US
William Thurmes - Longmont CO, US
Michael Wand - Boulder CO, US

International Classification:

C09K019/34
C09K019/30
C09K019/20
C09K019/12
C07C025/13
C07C069/76

US Classification:

428/001100, 252/299610, 560/056000, 570/127000, 570/129000, 570/131000, 252/299640, 252/299660, 252/299670, 252/299630

Abstract:

Chiral nonracemic, chiral racemic and achiral compounds useful as component of LC compositions which have a silane tail group which is partially fluorinated. The silane tail group comprises a perfluoroalkyl group. The silane tail group of this invention has the formula: where k is 0 or an integer ranging from 1-10; m and n are integers ranging from 1 to about 20; j is 0 or an integer ranging from 1 to 20; Z is —O— or a single bond; R, R, Rand R are alkyl groups or perfluorinated alkyl groups; and Ris a perfluorinated alkyl group. The invention also provides LC compositions comprising one or more compounds of the invention with partially fluorinated silane tails. The invention also provides optical devices, particularly display devices which contain an aligned layer of an LC composition comprising one or more silane compounds of this invention.

US Patent:

61397717, Oct 31, 2000

Filed:

Apr 4, 1997

Appl. No.:

8/833280

Inventors:

David M. Walba - Boulder CO
Daniel J. Dyer - Pasadena CA
Uwe Muller - Berlin, DE
Peter Cobben - Waalre, NL
Xin Hua Chen - Boulder CO
William Thurmes - Longmont CO
Michael Wand - Boulder CO

Assignee:

Displaytech, Inc. - Longmont CO

International Classification:

C09K 1952
C09K 1906
C07D23902
C07C 1908

US Classification:

25229901

Abstract:

This invention provides LC compositions useful as birefringent materials in electrooptic devices which exhibit zero or low negatively sloped birefringence dispersion (e. g. , exhibiting positive birefringence dispersion significantly lower than that of currently available LC compositions) or more preferably positively sloped birefringence dispersion in which birefringence of the material increases with wavelength. The invention provides compounds useful as components of LC compositions which exhibit negative birefringence where n. sub. o is higher than n. sub. e. The compounds of this invention are dimers of LC-like compounds in which the monomers are linked to each other through a high birefringence moiety (dimerization linker). The LC monomers consist of an LC core and one or two tail groups. Preferred monomers for this invention have low birefringence in comparison to the birefrigence of the monomer linking moiety.