(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2009/0032771 A1
`(43) Pub. Date:
`Feb. 5, 2009
`SAITO
`
`US 20090032771A1
`
`(52) us. c1. ................................................. .. 252/299.63
`(57)
`ABSTRACT
`A liquid crystal composition having a negative dielectric
`anisotropy that includes tWo components, Wherein the ?rst
`component is at least one compound selected from the group
`consisting of compounds represented by formula (1), and the
`second component is at least one compound selected from the
`group consisting of compounds represented by formula (2):
`
`(54) LIQUID CRYSTAL COMPOSITION AND
`LIQUID CRYSTAL DISPLAY DEVICE
`
`(75) Inventor:
`
`Masayuki SAITO, Chiba (JP)
`
`Correspondence Address:
`HOGAN & HARTSON LLP
`IP GROUP, COLUMBIA SQUARE
`555 THIRTEENTH STREET, N.W.
`WASHINGTON, DC 20004 (US)
`
`(73) Assignees:
`
`CHISSO CORPORATION, Osaka
`(JP); CHISSO
`PETROCHEMICAL
`CORPORATION, Tokyo (JP)
`
`(21) App1.No.:
`
`12/184,900
`
`(22) Filed:
`
`Aug. 1, 2008
`
`(30)
`
`Foreign Application Priority Data
`
`Aug. 1, 2007 (JP) .......................... .. JP 2007-200966
`
`Publication Classi?cation
`
`(51) Int. Cl.
`C09K 19/30
`
`(2006.01)
`
`(1)
`
`X1
`
`X2
`
`RIWZIAGiRZ (2)
`Rl‘®—®iR3
`
`wherein R1 and R2 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons and an alkenyl having 2 to 12 carbons;
`R3 is selected from the group consisting of an alkyl having 1
`to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl
`having 2 to 12 carbons and an alkenyl having 2 to 12 carbons
`in Which arbitrary hydrogen is replaced by ?uorine; Z1 is
`selected from the group consisting of a single bond, ethylene,
`carbonyloxy and methyleneoxy; X1 and X are each indepen
`dently selected from the group consisting of ?uorine and
`chlorine; and s is 0 or 1.
`
`1
`
`MERCK 1014
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`LIQUID CRYSTAL COMPOSITION AND
`LIQUID CRYSTAL DISPLAY DEVICE
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`[0001] This application claims priority under 35 U.S.C.
`§ll9 to Japanese Patent Application No. JP 2007-200966,
`?led Aug. 1, 2007, Which application is expressly incorpo
`rated herein by reference in its entirety.
`
`BACKGROUND OF THE INVENTION
`
`[0002] 1. Field of the Invention
`[0003] The invention relates to a liquid crystal composition
`suitable for use in an active matrix (AM) device, and an AM
`device containing the composition. More speci?cally, the
`
`tion has a nematic phase. General characteristics of the com
`position should be improved to obtain an AM device having
`good general characteristics. Table 1 below summarizes the
`relationship betWeen the general characteristics. The general
`characteristics of the composition Will be explained further
`based on a commercially availableAM device. A temperature
`range of a nematic phase relates to the temperature range in
`Which the device can be used. A desirable maximum tempera
`ture of the nematic phase is approximately 70° C. or more and
`a desirable minimum temperature is approximately —l0o C.
`or less. The viscosity of the composition relates to the
`response time of the device. A short response time is desirable
`for displaying a moving image. Accordingly, a loW viscosity
`of the composition is desirable. A loW viscosity at a loW
`temperature is more desirable.
`
`TABLE 1
`
`General Characteristics of a Liquid Crystal Composition and AM Device
`
`General Characteristics of a
`No Composition
`
`General Characteristics of anAM Device
`
`1 Temperature range of the nematic
`phase is Wide
`2 Viscosity is lOWl) and rotation viscosity
`is 10W
`3 Optical anisotropy is suitable
`4 Dielectric anisotropy is positively or
`negatively large
`
`5 Speci?c resistance is large
`
`6 It is stable With ultraviolet light and
`heat
`
`Usable temperature range is Wide
`
`Response time is short
`
`Contrast ratio is large
`Threshold voltage is lOW, electric poWer
`consumption is small and contrast ratio is
`large
`Voltage holding ratio is large and contrast
`ratio is large
`Service life is long
`
`1)A liquid crystal composition can be injected into a cell in a short time.
`
`invention relates to a liquid crystal composition having a
`negative dielectric anisotropy, and also relates to a device of
`an in-plane sWitching (IPS) mode or a vertical alignment
`(VA) mode.
`[0004] 2. RelatedArt
`[0005] In a liquid crystal display device, classi?cation
`based on an operating mode of liquid crystals includes phase
`change (PC), tWisted nematic (TN), super tWisted nematic
`(STN), electrically controlled birefringence (ECB), optically
`compensated bend (OCB), in-plane sWitching (IPS), vertical
`alignment (VA), and so forth. Classi?cation based on a driv
`ing mode includes a passive matrix (PM) and an active matrix
`(AM). PM is further classi?ed into static, multiplex and so
`forth, and AM is classi?ed into a thin ?lm transistor (TFT), a
`metal insulator metal (MIM) and so forth. TFT is further
`classi?ed into amorphous silicon and polycrystal silicon. The
`latter is classi?ed into a high temperature type and a loW
`temperature type according to the production process. Clas
`si?cation based on the light source includes a re?ection type
`utiliZing the natural light, a transmission type utiliZing a
`backlight, and a semi-transmission type utiliZing both the
`natural light and a backlight.
`[0006] These devices contain a liquid crystal composition
`having suitable characteristics. The liquid crystal composi
`
`[0007] The optical anisotropy of the composition relates to
`the contrast ratio of the device. A product (And) of the optical
`anisotropy (An) of the composition and the cell gap (d) of the
`device is designed to maximiZe the contrast ratio. A suitable
`value of the product depends on the kind of operation mode.
`In a device having aVA mode, a suitable value is in a range of
`from approximately 0.30 pm to approximately 0.40 um, and
`in a device having an IPS mode; a suitable value is in a range
`of from approximately 0.20 um to approximately 0.30 pm. In
`this case, a composition having a large optical anisotropy is
`desirable for a device having a small cell gap. A large dielec
`tric anisotropy of the composition contributes to a loW thresh
`old voltage, small electric poWer consumption and large con
`trast ratio. Accordingly, a large dielectric anisotropy is
`desirable. A large speci?c resistance of the composition con
`tributes to a large voltage holding ratio and a large contrast
`ratio of the device. Accordingly, a composition having a large
`speci?c resistance is desirable at room temperature and also
`at a high temperature in the initial stage. A composition
`having a large speci?c resistance is desirable at room tem
`perature and also at a high temperature after it has been used
`for a long time. The stability of the composition to ultraviolet
`light and heat relates to the service life of the liquid crystal
`display device. In the case Where the stability is high, the
`device has a long service life. These characteristics are desir
`
`2
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`able for an AM device used in a liquid crystal projector, a
`liquid crystal television and so forth.
`[0008] In an AM device having a TN mode, a composition
`having a positive dielectric anisotropy is used. In an AM
`device having a VA mode, a composition having a negative
`dielectric anisotropy is used. In an AM device having an IPS
`mode, a composition having a positive or negative dielectric
`anisotropy is used. A liquid crystal composition having a
`negative dielectric anisotropy is disclosed in the folloWing
`document.
`[0009] A conventional composition is disclosed in JP
`H2-4723 A/l 990.
`[0010] A desirable AM device is characterized as having a
`usable temperature range that is Wide, a response time that is
`short, a contrast ratio that is large, a threshold voltage that is
`loW, a voltage holding ratio that is large, a service life that is
`long, and so forth. Even one millisecond shorter response
`time is desirable. Thus, a composition having characteristics
`such as a high maximum temperature of a nematic phase, loW
`minimum temperature of a nematic phase, loW viscosity,
`large optical anisotropy, large positive or negative dielectric
`anisotropy, large speci?c resistance, high stability to ultravio
`let light, high stability to heat, and so forth is especially
`desirable.
`
`SUMMARY OF THE INVENTION
`
`[0011] The invention relates to a liquid crystal composition
`having a negative dielectric anisotropy that includes tWo com
`ponents, Wherein the ?rst component is at least one com
`pound selected from the group of compounds represented by
`formula (1), and the second component is at least one com
`pound selected from the group of compounds represented by
`formula (2):
`
`liquid crystal display device of the invention may occasion
`ally be expressed simply as “the composition” or “the
`device,” respectively. A liquid crystal display device is a
`generic term for a liquid crystal display panel and a liquid
`crystal display module. The “liquid crystal compound” is a
`generic term for a compound having a liquid crystal phase
`such as a nematic phase, a smectic phase and so forth, and also
`for a compound having no liquid crystal phase but being
`useful as a component of a composition. The useful com
`pound contains, for example, a 6-membered ring such as
`l,4-cyclohexylene and l,4-phenylene, and a rod like molecu
`lar structure. An optically active compound may occasionally
`be added to the composition. Even in the case Where the
`compound is a liquid crystal compound, the compound is
`classi?ed into an additive. At least one compound selected
`from a group of compounds represented by formula (1) may
`be abbreviated to “the compound (1).” The “compound (1)”
`means one compound, or tWo or more compounds, repre
`sented by formula (1). The other formulas are applied With the
`same rules. The term “arbitrary” means that not only the
`position but also the number are arbitrary, but the case Where
`the number is Zero is not included.
`[0014] A higher limit of a temperature range of a nematic
`phase may be abbreviated to “a maximum temperature.” A
`loWer limit of a temperature range of a nematic phase may be
`abbreviated to “a minimum temperature.” “A speci?c resis
`tance is large” means that the composition has a large speci?c
`resistance at room temperature and also at a high temperature
`in the initial stage; the composition has a large speci?c resis
`tance at room temperature and also at a high temperature even
`after it has been used for a long time. “A voltage holding ratio
`is large” means that a device has a large voltage holding ratio
`at room temperature and also at a high temperature in the
`initial stage, the device has a large voltage holding ratio at
`room temperature and also at a high temperature even after it
`has been used for a long time. In the description of the char
`acteristics such as optical anisotropy, the characteristics of the
`composition such as the optical anisotropy and so forth are
`values measured in the methods disclosed in Examples. The
`?rst component includes one compound or tWo or more com
`pounds. “A ratio of the ?rst component” means the percent
`age by Weight (% by Weight) of the ?rst component based on
`the total Weight of liquid crystal composition. A ratio of the
`second component and so forth are applied With the same
`rule. A ratio of an additive mixed With the composition means
`the percentage by Weight (% by Weight) based on the total
`Weight of liquid crystal composition.
`[0015] In the chemical formulas of the component com
`pounds, symbol R1 is used in plural compounds. In these
`compounds, plural Rl may be the same as or different from
`each other. In one case, for example, R1 of the compound (1)
`is ethyl and R1 of the compound (2) is ethyl. In another case,
`R1 of the compound (1) is ethyl and R1 of the compound (2) is
`propyl. This rule is also applicable to the symbols R2, R3 and
`so forth.
`[0016] One advantage of the invention is to provide a liquid
`crystal composition that satis?es many characteristics among
`the characteristics such as a high maximum temperature of a
`nematic phase, a loW minimum temperature of a nematic
`phase, a small viscosity, a large optical anisotropy, a large
`negative dielectric anisotropy, a large speci?c resistance, a
`high stability to ultraviolet light and a high stability to heat.
`Another advantage of the invention is to provide a liquid
`crystal composition that is properly balanced regarding at
`
`(1)
`
`x1
`
`x2
`
`RIWZIA©iRZ (2)
`Rl4®—®iR3
`
`wherein R1 and R2 are each independently selected from
`either an alkyl having 1 to 12 carbons, and alkoxy having 1 to
`12 carbons or an alkenyl having 2 to 12 carbons; R3 is selected
`from either an alkyl having 1 to 12 carbons, an alkoxy having
`1 to 12 carbons, an alkenyl having 2 to 12 carbons or an
`alkenyl having 2 to 12 carbons in Which arbitrary hydrogen is
`replaced by ?uorine; Z1 is either a single bond, ethylene,
`carbonyloxy or methyleneoxy; X1 and X2 are each indepen
`dently selected from either ?uorine or chlorine; and s is 0 or
`1.
`[0012] The invention also relates to a liquid crystal display
`device that includes the liquid crystal composition, and so
`forth.
`
`DETAILED DESCRIPTION OF THE INVENTION
`
`[0013] The terms used in the speci?cation and claims are
`de?ned as folloWs. The liquid crystal composition and/or the
`
`3
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`least tWo characteristics. Another advantage of the invention
`is to provide a liquid crystal display device that contains the
`liquid crystal composition. One aspect of the invention is to
`provide a liquid crystal composition that has a large optical
`anisotropy, a large negative dielectric anisotropy, a high sta
`bility to ultraviolet light and so forth, and is to provide anAM
`device that has a short response time, a large voltage holding
`ratio, a large contrast ratio, a long service life and so forth.
`[0017] The invention includes the folloWing features.
`[0018] 1. A liquid crystal composition having a negative
`dielectric anisotropy comprising tWo components, Wherein
`the ?rst component is at least one compound selected from the
`group consisting of compounds represented by formula (1),
`and the second component is at least one compound selected
`from the group consisting of compounds represented by for
`mula (2):
`
`-continued
`
`(Z)
`
`wherein R1 and R2 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons and an alkenyl having 2 to 12 carbons;
`R3 is selected from the group consisting of an alkyl having 1
`to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl
`having 2 to 12 carbons and an alkenyl having 2 to 12 carbons
`in Which arbitrary hydrogen is replaced by ?uorine; and Z1 is
`selected from the group consisting of a single bond, ethylene,
`carbonyloxy and methyleneoxy.
`[0020] 3. The liquid crystal composition according to item
`2, Wherein the ?rst component is a mixture of at least one
`compound selected from the group consisting of compounds
`represented by formula (1-1) and at least one compound
`selected from the group consisting of compounds represented
`by formula (1-2).
`[0021] 4. The liquid crystal composition according items 1
`to 3, Wherein a ratio of the ?rst component is from approxi
`mately 15% by Weight to approximately 70% by Weight, and
`a ratio of the second component is from approximately 20%
`by Weight to approximately 65% by Weight, based on the total
`Weight of the liquid crystal composition.
`[0022] 5. The liquid crystal composition according to any
`one of items 1 to 4, Wherein the composition further com
`prises at least one compound selected from the group consist
`ing of compounds represented by formula (3) as a third com
`ponent:
`
`(3)
`
`R3 @ Z2 @ Z3
`
`R4
`
`Wherein R3 and R4 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons, an alkenyl having 2 to 12 carbons and
`an alkenyl having 2 to 12 carbons in Which arbitrary hydrogen
`is replaced by ?uorine; ring A, ring B and ring C are each
`independently selected from the group consisting of an 1,4
`cyclohexylene,
`1,4-phenylene,
`2-?uoro-1,4-phenylene,
`3-?uoro-1,4-phenylene and 2,5-di?uoro-1,4-phenylene; Z2
`and Z3 are each independently selected from the group con
`sisting of a single bond, ethylene and carbonyloxy; and m is
`1 or 2.
`[0023] 6. The liquid crystal composition according to item
`5, Wherein the third component is at least one compound
`selected from the group consisting of compounds represented
`by formulas (3-1) to (3-4):
`
`Rsm R6
`
`(3-1)
`
`X1
`
`X2
`
`RIWZIAURZ
`Rl4®—®~R3
`
`(1)
`
`(2)
`
`wherein R1 and R2 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons and an alkenyl having 2 to 12 carbons;
`R3 is selected from the group consisting of an alkyl having 1
`to 12 carbons, an alkoxy having 1 to 12 carbons, an alkenyl
`having 2 to 12 carbons and an alkenyl having 2 to 12 carbons
`in Which arbitrary hydrogen is replaced by ?uorine; Z1 is
`selected from the group consisting of a single bond, ethylene,
`carbonyloxy and methyleneoxy; X1 and X2 are each indepen
`dently selected from the group consisting of ?uorine and
`chlorine; and s is 0 or 1.
`[0019] 2. The liquid crystal composition according to item
`1, Wherein the composition has a negative dielectric anisot
`ropy and comprises at least one compound selected from the
`group consisting of compounds represented by formulas
`(1-1) and (1-2) as the ?rst component, and at least one com
`pound selected from the group consisting of compounds rep
`resented by formula (2) as the second component:
`
`F
`
`F
`
`F
`
`F
`
`(1-1)
`
`(1-2)
`
`4
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`-continued
`2
`1
`Y Y
`
`Y3
`
`Y
`
`(3-2)
`
`(3-3)
`
`(3-4)
`
`wherein R5 and R6 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons and an
`alkenyl having 2 to 12 carbons; and Y1, Y2 and Y3 are each
`independently selected from the group consisting of hydro
`gen and ?uorine.
`[0024] 7. The liquid crystal composition according to item
`6, Wherein the third component is a mixture of at least one
`compound selected from the group consisting of compounds
`represented by formula (3-1) and at least one compound
`selected from the group consisting of compounds represented
`by formula (3-2).
`[0025] 8. The liquid crystal composition according to item
`6, Wherein the third component is a mixture of at least one
`compound selected from the group consisting of compounds
`represented by formula (3-1) and at least one compound
`selected from the group consisting of compounds represented
`by formula (3-4).
`[0026] 9. The liquid crystal composition according to any
`one of items 5 to 8, Wherein a ratio of the third component is
`from approximately 5% by Weight to approximately 35% by
`Weight based on the total Weight of the liquid crystal compo
`sition.
`[0027] 10. The liquid crystal composition according to any
`one of items 1 to 9, Wherein the composition further com
`prises at least one compound selected from the group consist
`ing of compounds represented by formula (4) as a fourth
`component:
`
`R3 ‘0% R4
`
`(4)
`
`Wherein R3 and R4 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons, an alkenyl having 2 to 12 carbons and
`an alkenyl having 2 to 12 carbons in Which arbitrary hydrogen
`is replaced by ?uorine; and ring D is selected from the group
`consisting of 1,4-cyclohexylene and 1,4-phenylene.
`
`[0028] 1 1 . The liquid crystal composition according to item
`10, Wherein a ratio of the fourth component is from approxi
`mately 5% by Weight to approximately 40% by Weight based
`on the total Weight of the liquid crystal composition.
`[0029] 12. The liquid crystal composition according to any
`one of items 1 to 11, Wherein the composition further com
`prises at least one compound selected from the group consist
`ing of compounds represented by formula (5) as a ?fth com
`ponent:
`
`X1
`
`X2
`
`(5)
`
`wherein R1 and R2 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons and an alkenyl having 2 to 12 carbons;
`ring E is selected from the group consisting of 1 ,4-cyclohexy
`lene and 1,4-phenylene; Z1 is selected from the group con
`sisting of a single bond, ethylene, carbonyloxy and methyl
`eneoxy; X1 and X2 are each independently selected from the
`group consisting of ?uorine and chlorine; and n is 1 or 2.
`[003 0]
`13. The liquid crystal composition according to item
`12, Wherein the ?fth component is at least one compound
`selected from the group consisting of compounds represented
`by formulas (5-1) to (5-4):
`
`(5-1)
`
`(5-2)
`
`(5-3)
`
`(5-4)
`
`F
`
`F
`
`F
`
`F
`
`R2
`
`F
`
`F
`
`F
`
`F
`
`R2
`
`R2
`
`R1
`
`R1
`
`R1
`
`wherein R1 and R2 are each independently selected from the
`group consisting of an alkyl having 1 to 12 carbons, an alkoxy
`having 1 to 12 carbons and an alkenyl having 2 to 12 carbons.
`[0031] 14. The liquid crystal composition according to item
`13, Wherein the ?fth component is a mixture of at least one
`compound selected from the group consisting of compounds
`represented by formula (5-1) and at least one compound
`selected from the group consisting of compounds represented
`by formula (5-3).
`
`5
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`[0032] 15. The liquid crystal composition according to item
`13, wherein the ?fth component is a mixture of at least one
`compound selected from the group consisting of compounds
`represented by formula (5-2) and at least one compound
`selected from the group consisting of compounds represented
`by formula (5-4).
`[0033] 16. The liquid crystal composition according to any
`one of items 12 to 15, Wherein a ratio of the ?fth component
`is from approximately 5% by Weight to approximately 50%
`by Weight based on the total Weight of the liquid crystal
`composition.
`[0034] 17. The liquid crystal composition according to any
`one of items 1 to 16, Wherein the composition has a maximum
`temperature of a nematic phase of approximately 70° C. or
`more, an optical anisotropy (250 C.) at a Wavelength of 589
`nm of approximately 0.08 or more, and a dielectric anisotropy
`(250 C.) at a frequency of 1 kHz of approximately —2 or less.
`[0035] 18. A liquid display device comprising the liquid
`crystal composition according to any one of items 1 to 17.
`[0036] 19. The liquid crystal display device according to
`item 18, Wherein the liquid crystal display device has an
`operation mode selected from the group consisting of a VA
`mode and an IPS mode, and has a driving mode of an active
`matrix mode.
`[0037] The invention further includes: (1) the composition
`described above, Wherein the composition further contains an
`optically active compound; (2) the composition described
`above, Wherein the composition further contains an additive,
`such as an antioxidant, an ultraviolet light absorbent and/or an
`antifoaming agent; (3) an AM device containing the compo
`sition described above; (4) a device having a TN, ECB, OCB,
`IPS or VA mode, containing the composition described
`above; (5) a device of a transmission type, containing the
`composition described above; (6) use of the composition
`described above as a composition having a nematic phase;
`and (7) use as an optically active composition by adding an
`optically active compound to the composition described
`above.
`[0038] The composition of the invention Will be explained
`in the folloWing order. First, the constitution of component
`compounds in the composition Will be explained. Second, the
`main characteristics of the component compounds and the
`main effects of the compounds on the composition Will be
`explained. Third, combinations of components in the compo
`sition, desirable ratios of the component compounds and the
`basis thereof Will be explained. Fourth, a desirable embodi
`ment of the component compounds Will be explained. Fifth,
`examples of the component compound Will be shoWn. Sixth,
`additives that may be added to the composition Will be
`explained. Seventh, the preparation methods of the compo
`nent compound Will be explained. Lastly, use of the compo
`sition Will be explained.
`[0039] First, the constitution of component compounds in
`the composition Will be explained. The composition of the
`invention is classi?ed into the compositionA and the compo
`sition B. The composition A may further contain other com
`pounds such as another liquid crystal compound, an additive,
`an impurity, and so forth. This liquid crystal compound is
`different from compound (1), compound (2), compound (3),
`compound (4) and compound (5). Such a liquid crystal com
`pound is mixed With the composition for the purpose of
`adjusting the characteristics of the composition. Among the
`liquid crystal compounds, an amount of a cyano compound is
`desirably small from the vieWpoint of stability to heat or
`
`ultraviolet light. The amount of a cyano compound is more
`desirably approximately 0% by Weight. The additive includes
`an optically active compound, an antioxidant, an ultraviolet
`light absorbent, a coloring matter, an antifoaming agent and
`so forth. The impurity is a compound contaminated in the
`process, such as, the synthesis of a component compound and
`so forth.
`[0040] The composition B essentially consists of the com
`pounds selected from compound (1), compound (2), com
`pound (3), compound (4) and compound (5). The term
`“essentially” means that the composition does not contain a
`liquid crystal compound Which is different from these com
`pounds. The term “essentially” also means that the composi
`tion may further contain an additive, an impurity, or other
`similar chemicals. The components of composition B are
`feWer than those of composition A. The composition B is
`preferable to compositionA from the vieWpoint of costs. The
`compositionA is preferable to composition B, because char
`acteristics of composition A can be further adjusted by mix
`ing With other liquid crystal compounds. Second, the main
`characteristics of the component compounds and the main
`effects of the compounds on the composition Will be
`explained. The main characteristics of the component com
`pounds are summarized in Table 2. In Table 2, the symbol L
`represents large or high, the symbol M represents a middle
`degree, and the symbol S represents small or loW. The sym
`bols L, M and S are classi?cation based on qualitative com
`parison among the component compounds.
`
`TABLE 2
`
`Characteristics of Compounds
`
`Maximum temperature
`Viscosity
`Optical anisotropy
`Dielectric anisotropy
`Speci?c resistance
`
`(1)
`
`S-M
`M-L
`S-M
`M-Ll)
`L
`
`Compound
`
`(2) (3)
`
`(4)
`
`(5)
`
`S M-L
`S M-L
`M M-L
`0
`0
`L L
`
`S S-M
`S M-L
`S M-L
`0 M-Ll)
`L L
`
`1)A value of dielectric anisotropy is negative, and the symbols shoW magni
`tude of absolute values.
`
`[0041] The main effects of the component compounds to
`the characteristics of the composition upon mixing the com
`ponent compounds to the composition are as folloWs. Com
`pound (l) increases the absolute value of the dielectric anisot
`ropy. Compound (2) increases the optical anisotropy and
`decreases the viscosity. Compound (3) increases the maxi
`mum temperature. Compound (4) decreases the optical
`anisotropy and decreases the viscosity. Compound (5)
`decreases the minimum temperature and increases the abso
`lute value of the dielectric anisotropy.
`[0042] Third, combinations of components in the compo
`sition, desirable ratios of the component compounds and the
`basis therefore Will be explained. Examples of the combina
`tions of the components in the composition include (?rst
`component+second component), (?rst component+second
`component+third component), (?rst component+second
`component+fourth component), (?rst component+second
`component+?fth component), (?rst component+ second com
`ponent+third component+fourth component), (?rst compo
`nent+second component+third component+?fth compo
`nent),
`(?rst
`component+second
`component+fourth
`component+?fth component) and (?rst component+second
`
`6
`
`

`
`US 2009/0032771 A1
`
`Feb. 5, 2009
`
`component+third component+fourth component+?fth com
`ponent). Desirable examples of the combinations of the com
`ponents in the composition include (?rst component+second
`component+four‘th component), (?rst component+second
`component+third component+fourth component) and (?rst
`component+second component+third component+four‘th
`component+?fth component). More desirable examples of
`the combinations of the components in the composition
`include (?rst component+second component+third compo
`nent +fourth component) and (?rst component+second com
`ponent+third component+four‘th component+?fth compo
`nent).
`[0043] A desirable ratio of the ?rst component is approxi
`mately 15% by Weight or more for increasing the absolute
`value of the dielectric anisotropy, and is approximately 70%
`by Weight or less for decreasing the minimum temperature. A
`more desirable ratio is from approximately 20% by Weight to
`approximately 65% by Weight. A particularly desirable ratio
`is from approximately 25% by Weight to approximately 60%
`by Weight.
`[0044] A desirable ratio of the second component is
`approximately 5% by Weight or more for increasing the opti
`cal anisotropy and decreasing the viscosity, and is approxi
`mately 30% by Weight or less for decreasing the minimum
`temperature. A more desirable ratio is from approximately
`5% by Weight to approximately 25% by Weight. A particu
`larly desirable ratio is from approximately 5% by Weight to
`approximately 20% by Weight.
`[0045] The third component is particularly suitable for pre
`paring a composition having a high maximum temperature of
`a nematic phase. A desirable ratio of the component is from
`approximately 5% by Weight to approximately 35% by
`Weight. A more desirable ratio is from approximately 5% by
`Weight to approximately 30% by Weight. A particularly desir
`able ratio is from approximately 5% by Weight to approxi
`mately 25% by Weight.
`[0046] A desirable ratio of the fourth component is
`approximately 5% by Weight or more for decreasing the vis
`cosity, and is approximately 40% by Weight or less for
`increasing the absolute value of the dielectric anisotropy. A
`more desirable ratio is from approximately 5% by Weight to
`approximately 35% by Weight. A particularly desirable ratio
`is from approximately 10% by Weight to approximately 35%
`by Weight.
`[0047] A desirable ratio of the ?fth component is approxi
`mately 5% by Weight or more for increasing the absolute
`value of the dielectric anisotropy, and is approximately 50%
`by Weight or less for decreasing the minimum temperature. A
`more desirable ratio is from approximately 5% by Weight to
`approximately 45% by Weight. A particularly desirable ratio
`is from approximately 10% by Weight to approximately 40%
`by Weight.
`[0048] Fourth, a desirable embodiment of the component
`compound Will be explained. R1 and R2 are each indepen
`dently selected from either an alkyl having 1 to 12 carbons, an
`alkoxy having 1 to 12 carbons or an alkenyl having 2 to 12
`carbons. Desirable R1 is an alkyl having 1 to 12 carbons or an
`alkenyl having 2 to 12 carbons in order to decrease the mini
`mum temperature and to decrease the viscosity. Desirable R2
`is an alkoxy having 1 to 12 carbons in order to increase the
`absolute value of the dielectric anisotropy. R3 and R4 are each
`independently selected from either an alkyl having 1 to 12
`carbons, an alkoxy having 1 to 12 carbons, an alkenyl having
`2 to 12 carbons or alkenyl having 2 to 12 carbons in Which
`
`arbitrary hydrogen is replaced by ?uorine. Desirable R3 and
`R4 are each an alkyl having 1 to 12 carbons or alkenyl having
`2 to 12 carbons in order to enhance the stability to ultraviolet
`light or heat and so forth, and to decrease the viscosity. R5 and
`R6 are each independently selected from either an alkyl hav
`ing 1 to 12 carbons or alkenyl having 2 to 12 carbons. Desir
`able R5 and R6 are each an alkyl having 1 to 12 carbons in
`order to enhance the stability to ultraviolet light or heat and so
`forth.
`[0049] Desirable alkyl is methyl, ethyl, propyl, butyl, pen
`tyl, hexyl, heptyl, or octyl. More desirable alkyl is ethyl,
`propyl, butyl, pentyl, or heptyl for decreasing a viscosity.
`[0050] Desirable alkoxy is methoxy, ethoxy, propoxy,
`butoxy, pentyloxy, hexyloxy, or heptyloxy. More desirable
`alk