# US 5,705,094 A · Antiferroelectric liquid crystal composition and liquid crystal display element using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,094 A - Document ID: US5705094A - Status: Granted - Kind: A - Application number: 08/503,970 - Filed: 1995-07-19 - Granted: 1998-01-06 - Earliest claimed: 1994-07-19 - Assignees: Nippon Soken, Inc. - Inventors: Akira Takeuchi; Norio Yamamoto; Takayuki Fujikawa; Toshio Yamamoto - Web page: https://patentgrep.com/patent/US5705094A ## CPC - C09K 19/0266: {Antiferroelectrics} - C07C 69/90: with esterified hydroxyl and carboxyl groups - C07C 69/94: of polycyclic hydroxy carboxylic acids, the hydroxy groups and the carboxyl groups of which are bound to carbon atoms of six-membered aromatic rings - C09K 19/2021: {Compounds containing at least one asymmetric carbon atom} - G02F 1/0063: {Optical properties, e.g. absorption, reflection or birefringence (materials for non-linear optics G02F1/355)} - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract The antiferroelectric liquid crystal composition comprising at least one chiralsmectic liquid crystal compound having a positive specific rotatory power ›.alpha.!.sub.D.sup.25 and at least one chiralsmectic liquid crystal compound having a negative specific rotatory power, and the value of the specific rotatory power of the composition is between -25.degree. and +25.degree. C. This invention provides a method for blending liquid crystal compounds to form an antiferroelectric liquid crystal composition which has a decreased dark luminance of a liquid crystal display element. ## Claims ### Claim 1 An antiferroelectric liquid crystal composition comprising: at least one first chiralsmectic liquid crystal compound having a positive specific rotatory power ›.alpha.!.sub.D.sup.25 (hereinafter the specific rotatory powers described are ›.alpha.!.sub.D.sup.25) and an R type absolute configuration; and at least one second chiralsmectic liquid crystal compound having a negative specific rotatory power and an R type absolute configuration, wherein the at least one first and second chiralsmectic liquid crystal compounds are optically active compounds represented by the following general formula (II), ##STR37## wherein m is an integer of 1 to 18; n is an integer of 3 to 10; A, B and C are one or a combination of two selected from the following formulae (III); X.sup.1, X.sup.2 and X.sup.3 are independently selected from the following formulae (IV); Z.sup.1, Z.sup.2 and Z.sup.3 are independently selected from the following formulae (V); and Y is any one of CH.sub.3, CF.sub.3, C.sub.2 H.sub.5 and C.sub.2 F.sub.5, (III): ##STR38## (IV) single bond (--), --COO--, --OCO--, --CO--, --O--, --CH.sub.2 O-- and --C.tbd.C--, and (V) H, F, Cl, Br, CN and CH.sub.3, and wherein the composition has a specific rotatory power of from 0.degree. to +25.degree.. ### Claim 2 (depends on 1) The antiferroelectric liquid crystal composition according to claim 1, wherein Y in the at least one first chiralsmectic liquid crystal compound is CF.sub.3, and wherein Y in the at least one second chiralsmectic liquid crystal compound is CH.sub.3. ### Claim 3 (depends on 1) The antiferroelectric liquid crystal composition according to claim 1, which comprises 40 to 90% by weight of the at least one first chiralsmectic liquid crystal compound represented by the formula (II) wherein the absolute configuration is R type and the specific rotatory power is positive, and 10 to 60% by weight of the at least one second chiralsmectic liquid crystal compound represented by the formula (II) wherein the absolute configuration is R type and the specific rotatory power is negative. ### Claim 4 (depends on 1) A liquid crystal display device comprising the liquid crystal composition according to claim 1. ### Claim 5 (depends on 2) A liquid crystal display device comprising the liquid crystal composition according to claim 2. ### Claim 6 (depends on 3) A liquid crystal display device comprising the liquid crystal composition according to claim 3. ### Claim 7 An antiferroelectric liquid crystal composition comprising: at least one first chiralsmectic liquid crystal compound having a negative specific rotatory power and an S type absolute configuration; and at least one second chiralsmectic liquid crystal compound having a positive specific rotatory power and an S type absolute configuration, wherein the at least one first and second chiralsmectic liquid crystal compounds are optically active compounds represented by the following general formula (II), ##STR39## wherein m is an integer of 1 to 18; n is an integer of 3 to 10; A, B and C are one or a combination of two selected from the following formulae (III); X.sup.1, X.sup.2 and X.sup.3 are independently selected from the following formulae (IV); Z.sup.1, Z.sup.2 and Z.sup.3 are independently selected from the following formulae (V); and Y is any one of CH.sub.3, CF.sub.3, C.sub.2 H.sub.5 and C.sub.2 F.sub.5, (III): ##STR40## (IV) single bond (--), --COO--, --OCO--, --CO--, --O--, --CH.sub.2 O-- and --C.tbd.C--, and (V) H, F, Cl, Br, CN and CH.sub.3, and wherein the composition has a specific rotatory power of from -25.degree. to 0.degree.. ### Claim 8 (depends on 7) The antiferroelectric liquid crystal composition according to claim 7, wherein Y in the at least one first chiralsmectic liquid crystal compound is CF.sub.3, and wherein Y in the at least one second chiralsmectic liquid crystal compound is CH.sub.3. ### Claim 9 (depends on 7) The antiferroelectric liquid crystal composition according to claim 7, which comprises 40 to 90% by weight of the at least one first chiralsmectic liquid crystal compound represented by the formula (II) wherein the absolute configuration is S type and the specific rotatory power is negative, and 10 to 60% by weight of the at least one second chiralsmectic liquid crystal compound represented by the formula (II) wherein the absolute configuration is S type and the specific rotatory power is positive. ### Claim 10 (depends on 7) A liquid crystal display device comprising the liquid crystal composition according to claim 7. ### Claim 11 (depends on 8) A liquid crystal display device comprising the liquid crystal composition according to claim 8. ### Claim 12 (depends on 9) A liquid crystal display device comprising the liquid crystal composition according to claim 9. ### Claim 13 An antiferroelectric liquid crystal composition comprising: at least one first chiralsmectic liquid crystal compound having a positive specific rotatory power and an asymmetric chemical constitution; and at least one second chiralsmectic liquid crystal compound having a negative specific rotatory power and an asymmetric chemical constitution, wherein the at least one first and second chiralsmectic liquid crystal compounds are represented by the following formula (I), ##STR41## wherein R is any one of CH.sub.3, CF.sub.3, C.sub.2 H.sub.5 and C.sub.2 F.sub.5, and wherein an absolute configuration of the at least one first and second chiralsmectic liquid crystal compounds are both R type or both S type, and the composition has a specific rotatory power of from -25.degree. to +25.degree.. ### Claim 14 (depends on 13) A liquid crystal display device comprising the liquid crystal composition according to claim 13.