JPH07242874A - Nematic liquid crystal composition and liquid crystal display using the same - Google Patents

Abstract

PURPOSE:To obtain the subject composition exhibiting nematic phase down to lower temperature, low in threshold voltage, having high voltage retentivity, excellent in stability, for use in e.g. liquid crystal displays, comprising trifluorophenyl group-contg. dicyclohexane-based compound(s). CONSTITUTION:This composition comprises compound(s) selected from compounds of formula I (R<1> is a 2-7C alkyl), compounds of formula II (R<2> is a 2-7C alkenyl) and compounds of formula III (R<3> is 1 2-7C alkyl). The composition has the following characteristics: exhibiting nematic phase over a wide range of temperatures, esp. to lower temperatures; low in threshold voltage; having high voltage retentivity; and excellent in chemical stability. The liquid crystal display using the composition has the following advantages: improved in the flickering or cross talk phenomena of displayed picture images; useful for e.g. active matrix system with much information; and giving good driving characteristics and display characteristics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nematic liquid crystal composition useful as an electro-optical display material and a liquid crystal display device using the nematic liquid crystal composition.

[0002]

2. Description of the Related Art TN-LCD is a typical liquid crystal display device.
(Twisted nematic liquid crystal display element)
Used in clocks, calculators, electronic organizers, pocket computers, word processors, personal computers, etc. On the other hand, the amount of information displayed on one screen is increasing with the increase in processing information of OA devices.
ffer) et al. [SID '85 Digest, p. 120 (1985)] or Kinugawa et al. [SID '86 Digest, p. 122 (1986)]
STN (Super Twisted Nematic) -LCD has been developed and is beginning to be widely used in displays for high information processing such as word processors and personal computers.

Further, because of its excellent display quality, an active matrix type liquid crystal display device has been put on the market as an effective one for application fields of displays such as liquid crystal televisions, projector displays and computers. The active matrix display method uses a TFT for each pixel
A switching element such as (thin film transistor) or MIM (metal insulator metal) is used, and it is important in this method that leakage current is small, that is, high voltage holding ratio. Therefore, in order to deal with such a display device, new liquid crystal compounds or liquid crystal compositions have been proposed at present.

[0004]

[Problems to be Solved by the Invention] This TN-LCD or STN-LCD
Have problems such as chemical stability of liquid crystal materials, low voltage drivability and response characteristics of liquid crystal display devices.

For example, an STN-LCD having a large amount of information such as a word processor and a personal computer is required to have a good driving characteristic with a high time division number. However, an increase in the time division number causes an increase in drive voltage, which results in a drive circuit. Have a great influence on. One way to reduce this is

[0006]

[Equation 1]

(Wherein V _th is a threshold voltage, k is a proportional constant, K is an elastic constant, and Δε is a dielectric anisotropy). A method of reducing a driving voltage by using a material is known. However, since many such liquid crystal materials tend to increase the viscosity of the liquid crystal material, it is difficult to obtain good response characteristics or the capacitance component of each pixel is increased. There are problems such as narrowing the possible driving frequency range and causing a crosstalk phenomenon.

On the other hand, in the case of a conventional liquid crystal material that can be driven at a low voltage, it is generally known that the resistance value is low at the prepared initial stage or after an accelerated test by heating or ultraviolet irradiation. Such a low resistance value of the liquid crystal material is not preferable because it causes a flicker of the display screen and a decrease in contrast due to an increase in the number of time divisions.

Further, in order to compensate for the dark image quality due to the increase in the amount of information, it is common to use a backlight as an auxiliary light source in STN-LCD. For this reason, liquid crystal materials used for backlight STN-LCDs are required to have new chemical stability such as heat resistance and light resistance.

In addition to these required characteristics, particularly in the active matrix system, it is important that the leakage current is small and the voltage holding ratio is high in order to obtain uniform and high contrast. In order to obtain such characteristics,
For example, the following compounds have been used.

[0011]

[Chemical 6]

(In the formula, R ¹⁰ represents a straight-chain alkyl group, and X ² represents a hydrogen atom or a fluorine atom.) However, even when such a compound is used, nematic liquid crystallinity is exhibited in a wide temperature range, especially at a low temperature. It has not been possible to prepare a composition satisfying both the requirement of maintaining the above and the threshold voltage required for the active matrix system being sufficiently reduced.

In addition, in order to obtain uniform and high contrast liquid crystal display characteristics, the thickness d of the liquid crystal layer of the liquid crystal panel.
And the birefringence Δn of the liquid crystal material Δn · d is 0.40
It is said that it is preferable to adjust to a range of 0.55 (hereinafter, referred to as first minimum).
Since the thickness d of the light control layer used in the current liquid crystal panel manufacturing process is about 4.5 μm or more, the birefringence Δn of the liquid crystal material should be in the range of 0.07 to 0.10. Is required to be adjusted. However, conventionally, when the birefringence Δn of the liquid crystal material is adjusted to this range, the threshold voltage V of the display device manufactured using the birefringence Δn is adjusted.
On the contrary, _th tends to rise, and it was difficult to satisfy both at the same time.

The problem to be solved by the present invention is to solve the above-mentioned problems, and in particular, it exhibits liquid crystallinity in a wide temperature range, has a low threshold voltage, and has a sufficiently high voltage holding ratio. It is an object of the present invention to provide a liquid crystal composition having a birefringence index Δn suitable for the setting conditions of the device, and further to provide a liquid crystal display device which is free from flicker and excellent in contrast by using this liquid crystal composition.

[0015]

In order to solve the above-mentioned problems, the present invention provides the following nematic liquid crystal compositions.

First, as the first liquid crystal composition of the present invention,
(1) General formula (I)

[0017]

[Chemical 7]

(Wherein R ¹ represents a linear alkyl group having 2 to 7 carbon atoms) and (2)
General formulas (II) to (III)

[0019]

[Chemical 8]

(Wherein R ² represents a straight chain alkenyl group having 2 to 7 carbon atoms and R ³ represents a straight chain alkyl group having 2 to 7 carbon atoms). There is provided a nematic liquid crystal composition containing a compound selected from the group.

As the second liquid crystal composition of the present invention,
(1) A compound represented by the above general formula (I) and (2)
General formula (IV) ~ (V)

[0022]

[Chemical 9]

(Wherein each R ⁴ independently represents a linear alkyl group having 2 to 7 carbon atoms) is characterized by containing a compound selected from the group consisting of compounds A nematic liquid crystal composition is provided.

Further, as the third liquid crystal composition of the present invention,
(1) a compound represented by the general formula (I), (2) a compound selected from the group consisting of the compounds represented by the general formulas (II) to (III), and (3) the general formula (IV). ) ~ (V)
There is provided a nematic liquid crystal composition containing a compound selected from the group consisting of compounds represented by:

In the present invention, in the above-mentioned first to third liquid crystal compositions, the components other than the above are (A) the general formulas (VI) to (XI).

[0026]

[Chemical 10]

(In the formula, R ⁵ represents a linear alkenyl group having 2 to 7 carbon atoms, R ⁶ independently represents a linear alkyl group having 2 to 7 carbon atoms, and X ¹ Each independently represent H or F, and r represents 0 or 1), and preferably contains one or more compounds selected from the group consisting of compounds represented by

Here, the general formulas (I) to (XI) according to the present invention are described.
Table 1 below shows typical examples of the compounds represented by and their phase transition temperatures. In the table below, m. p. Is the temperature at which the phase transition from the crystalline phase to the liquid crystal phase or the isotropic liquid phase is expressed by c.
p. Are the temperatures at which the liquid crystal phase changes to the isotropic liquid phase. Each liquid crystal compound was used after being sufficiently purified by removing impurities by methods such as distillation, column purification, and recrystallization.

[0029]

[Table 1]

The liquid crystal composition of the present invention is characterized in that it contains the compound represented by the above general formula (I) as an essential component. The compound represented by the general formula (I) has an effect of reducing the driving voltage of the liquid crystal composition and maintaining and improving the high voltage holding ratio, even though the dielectric anisotropy is relatively small at around +8. . The birefringence Δn is 0.0
Since it is extremely small, around 6, it has excellent characteristics in preparing a liquid crystal composition used in a device used to satisfy the conditions of the above-mentioned first minimum. However, the compound of the general formula (I) has a drawback that it tends to exhibit a smectic phase. For example, a composition (2-1) consisting only of the compound of general formula (I)

[0031]

[Chemical 11]

Has a nematic phase temperature range of 77 to 56.
It was difficult to prepare a nematic liquid crystal composition which can be driven at a particularly low temperature by using only the compound of the general formula (I), which is extremely narrow at 0 ° C.

The present inventors have examined the combination of the compound represented by the general formula (I) with various liquid crystal compounds, and as a result, as shown in the first to third liquid crystal compositions of the present invention,
(II) ~ (III) by using a compound selected from the group consisting of compounds and / or compounds selected from the group consisting of compounds represented by the general formula (IV) ~ (V) It has been found that a nematic liquid crystal composition that can be used in a wide temperature range can be prepared without impairing the excellent properties of the compound represented by (I).

In the first to third nematic liquid crystal compositions of the present invention, it is preferable that the compound other than the compound represented by the general formula (I) contains a compound represented by the general formula (II), In addition to this, in addition to the general formula (III)
It is also preferable to contain a compound represented by and / or a compound represented by the general formula (V).

As described above, in the first to third liquid crystal compositions of the present invention, in addition to the components represented by the general formulas (I) to (V), (A) the general formulas (VI) to (XI). It is preferable to contain a compound selected from the group consisting of compounds represented by

Among them, (1) a compound selected from the group consisting of compounds represented by the general formulas (VI) to (VII) and /
Alternatively, (2) it is preferable to contain a compound selected from the group consisting of the compounds represented by the general formulas (IX) to (X). Specific examples of the combination include the following.

(I) + (II) + (VI) + (VII) + (X) ・ (I) + (II) + (VI) + (VII) + (IX) + (X) ・ (I ) + (II) + (III) + (VI) ・ (I) + (II) + (VII) ・ (I) + (II) + (III) + (V) + (VIII) + (IX) + (X) + (XI)

The compounds represented by the general formulas (II) to (XI) used in the nematic liquid crystal composition of the present invention have the effect of maintaining or reducing the driving voltage without lowering the voltage holding ratio of the composition. Have. Such an effect is
It is considered that each of the compounds (II) to (XI) has a 3,4,5-trifluorophenyl group or a 3,4-difluorophenyl group.

Among them, the compound represented by the general formula (II) or (VI) is important in adjusting the elastic constant ratio (K ₃₃ / K ₁₁ ) which plays an important role in display characteristics according to the use. It is also a compound and can reduce the viscosity of the nematic liquid crystal composition. Therefore, by using it in combination with the compound of the general formula (I), it is possible to easily prepare a liquid crystal material which exhibits a nematic phase in a wide temperature range and has a high-speed response. As the compounds represented by the general formula (II) or (VI), the following compounds are particularly excellent.

[0040]

[Chemical 12]

Further, the compounds represented by the general formulas (III) to (V) have the effect of reducing the driving voltage of the liquid crystal composition, but using these compounds, a liquid crystal composition exhibiting a nematic phase up to a low temperature is used. Was difficult to prepare. In particular, the compound of the general formula (V) is inferior in compatibility with other liquid crystal compounds, and conventionally, this compound is, for example, one of the general formulas (2-2) to (2-4).

[0042]

[Chemical 13]

(In the formula, R ¹¹ represents an alkyl group, and X ³
Represents F, OCF ₃ , OCHF ₂ or CF ₃ , X ⁴ and X ⁵ each independently represent H or F, and X ⁶ represents OC
It represents F ₃ , OCHF ₂ or CF ₃ , and s represents 0 or 1. It was essential to use it in combination with the compound represented by However, even if such means are used, the above-mentioned problems have not been sufficiently solved.

Regarding the compounds represented by the general formulas (III) to (V), for example, JP-A-5-500681 discloses a compound represented by the general formula (2-2) and a general formula relating to the present invention. (II
There is a description about a liquid crystal composition in which the compound of I) to (V) or (VII) is mixed, and the mixing ratio is preferably 1: 4 to 1: 1 and the content of the compound of the general formula (2-2) is Is more preferably 40% or more. However, such a composition has a nematic phase-isotropic liquid phase transition temperature T _NI as low as 80 ° C. or lower, or TN-LCD.
In the present situation, no one satisfying the characteristics currently required, such as a high threshold voltage V _th of 1.5 V or more, has not been obtained. Furthermore, the general formula (2-
Since the content of the compound of 2) is large, the vapor pressure temperature characteristic is deteriorated, the liquid crystal injection condition becomes strict in the manufacturing process of the liquid crystal display panel, or a new problem such as uneven injection occurs. It wasn't practical.

Further, for example, in Japanese Patent Publication No. 5-500830,
The compound of the general formula (2-4) and the general formula relating to the present invention
There is a description of a liquid crystal composition in which the compound of (III) to (V) or (VII) is mixed, and the mixing ratio is 1: 4 to 1: 1.
It is described that the content of the compound of the general formula (2-4) is 40% or more is more preferable. However, since such a composition also has a large content of the compound of the general formula (2-4) in order to improve the nematic phase at low temperature, T _NI or V _th is similar to the above. It was the current situation that no product satisfying the required characteristics was obtained. Furthermore, when a material having a large birefringence Δn of 0.12 or more is used, the first minimum (Δn
In order to satisfy the condition (d = 0.5), the cell thickness d needs to be about 4 μm or less, and the uniform cell manufacturing conditions in the manufacturing process of the liquid crystal display panel become strict, or display unevenness occurs. It is not practical because it causes a new problem such as generation.

On the other hand, in the present invention, by using the compound of the general formula (I) in combination, the above-mentioned problems can be solved and the excellent characteristics of each compound are not impaired. It is possible to obtain an excellent composition that can be driven in a wide temperature range up to a low temperature.

Such an effect is apparent from the following example, for example. Composition comprising only compound of general formula (V) (2-5)

[0048]

[Chemical 14]

Shows a nematic phase in the range of 71 to 44 ° C. Further, a composition (2-6) comprising the compound of general formula (V) and the compound of general formula (VII)

[0050]

[Chemical 15]

Shows a nematic phase in the range of 85 to 33 ° C., and the temperature range of the nematic phase, particularly the lower limit temperature, does not decrease so much even if the number of components increases. However, a composition (2-7) obtained by mixing the compound of the general formula (I) and the compound of the general formula (V), which are essential components of the present invention.

[0052]

[Chemical 16]

Shows a nematic phase in the range of 74 to 18 ° C. and is a composition (2-8) obtained by mixing the compound of the general formula (I) and the compound of the general formula (VII).

[0054]

[Chemical 17]

Indicates a nematic phase in the range of 89 to 0 ° C., and the nematic phase largely expands to the low temperature side. A composition (2-9) obtained by mixing the compound of the general formula (I) and the compound of the general formula (II)

[0056]

[Chemical 18]

Shows a nematic phase in the range of from 83 to 15 ° C., and is a composition obtained by mixing the compound of general formula (I), the compound of general formula (II) and the compound of general formula (VI) (2- 10)

[0058]

[Chemical 19]

Shows a nematic phase in the range of 90 to -30 ° C., and is a composition (2-11) obtained by mixing the compound of the general formula (I) and the compound of the general formula (VI).

[0060]

[Chemical 20]

Shows a nematic phase in the range of 96 to -20 ° C., and it is clear that the maximum temperature of the nematic phase is high, and the temperature range of the nematic phase is greatly expanded to the low temperature side.

Therefore, by using the compound represented by the general formula (I) in combination with the compound represented by the general formulas (II) to (XI), a nematic liquid crystal composition which can be used in a wider temperature range, particularly in a low temperature side. It is clear that

In addition, Japanese Patent Publication No. 5-501735 discloses a compound having a 3,4,5-trifluorophenyl group represented by the general formula (2-3) and a 3,4-difluorophenyl group. There is a description about a liquid crystal composition in which a compound is mixed, and this mixing ratio is preferably 1: 4 to 1: 1 and has a 3,4,5-trifluorophenyl group represented by the above general formula (2-3). It is described that it is preferable that the content of the compound is 50% by weight or less. This technology
Although it was developed to achieve a lower threshold voltage, it has not been sufficiently reduced, and the cause is that the mutual compatibility of liquid crystal compounds or the nematic phase is narrow at low temperatures. It seems that it is because it cannot be contained.

However, the liquid crystal composition of the present invention comprises a compound having a 3,4,5-trifluorophenyl group represented by the general formula (I) to (III) or (V), a compound represented by the general formula (IV), (V
Even if the mixing ratio with the compound having a 3,4-difluorophenyl group represented by I) or (VII) is 1: 1 or more,
Alternatively, even if the total content of the compounds having a 3,4,5-trifluorophenyl group is 50% by weight or more, as is apparent from the above examples, a nematic liquid crystal composition which can be used in a wide temperature range is prepared. it can.

The compounds represented by the general formulas (VI) to (XI) (A) that can be used in the first to third nematic liquid crystal compositions of the present invention have the effects of maintaining and improving the above-mentioned characteristics. Have each.

More specifically, the compounds represented by the general formulas (VI) to (XI) have a birefringence (Δn) of the liquid crystal composition of 0.07 to
The value can be optimized within the range of 0.10, whereby the effects of improving the viewing angle characteristics of the liquid crystal display device, increasing the contrast ratio, and the like can be obtained. Further, it has the effect of expanding the nematic phase temperature range of the composition to the high temperature side and the low temperature side, and can further expand the drivable temperature range of the liquid crystal display device.

Among these compounds, the compounds of the general formulas (VIII) and (I
The compound of X) or (XI) is-(CH ₂)_Four-Or-
(CH₂)₂-Having a linking group, the above general formula (I) ~ (VII)
Excellent compatibility with liquid crystal compositions consisting of
It Further, the compound represented by the general formula (IX) has the general formula (V
In III), compared with the compound with r = 0,
The liquid crystal composition of the present invention is
Even if the compound of the formula (IX) is heavily used, the manufacturing process of the liquid crystal display panel
Liquid crystal injection conditions can be relaxed, and large liquid
Injecting unevenness in the manufacturing process of crystal panel
It also has features.

The first to third liquid crystal compositions of the present invention are (B) general formulas (XII) to (XVI).

[0069]

[Chemical 21]

(In the formula, R ^7's each independently represent a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^8's each independently represent a linear alkyl group having 2 to 7 carbon atoms. Group represented by a linear alkyl group, an alkenyl group, an alkoxy group or an alkenyloxy group, each R ⁹ independently represents a linear alkyl group having 2 to 7 carbon atoms). It may contain a compound.

Among them, it is particularly preferable to contain the compound represented by the general formula (XII), the general formula (I), (II),
Liquid crystal compositions containing the compounds represented by (VI), (IX), (X) and (XII) are particularly preferred.

The compounds represented by the general formulas (XII) to (XVI) can extend the temperature range of the nematic phase of the liquid crystal composition especially to the low temperature side. Moreover, since these compounds can also reduce the viscosity of the nematic liquid crystal composition, it is possible to obtain a liquid crystal material having a high-speed response in a wide temperature range. Particularly, the compound represented by the general formula (XII) or (XIII) is very suitable for obtaining such an effect.

Further, the liquid crystal composition of the present invention has the general formula (I)
In addition to the compounds (XVI) to (XVI), in order to improve other properties of the liquid crystal composition, a normal nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal or the like recognized as a liquid crystal compound may be contained.

The content of the compound represented by formula (I) in the liquid crystal composition of the present invention is preferably in the range of 3 to 60% by weight. In addition, (2) general formulas (II) to (III)
The total content of the compounds selected from the group consisting of the compounds represented by the formula (3) is preferably in the range of 3 to 50% by weight. At this time, the content of each compound is the compound represented by the general formula (II). In the range of 0 to 25% by weight and the general formula
It is more preferable to contain the compound represented by (III) in the range of 0 to 30% by weight.

Further, (3) the content of the compound selected from the group consisting of the compounds represented by the general formulas (IV) to (V) is preferably in the range of 3 to 40% by weight. The content of each compound is preferably 0 to 30% by weight of the compound represented by the general formula (IV), and 3 to 30% by weight of the compound represented by the general formula (V). .

When the compounds represented by the general formulas (VI) to (VII) are contained, the total content is preferably in the range of 3 to 55% by weight. At this time, the content of each compound is , Each in the range of 0 to 35% by weight. When the compounds represented by the general formulas (VIII) to (XI) are contained, the total content is preferably in the range of 3 to 35% by weight. At this time, the content of each compound is It is preferably in the range of 0 to 20% by weight, respectively.
When the compound selected from the group consisting of the compounds represented by the general formulas (XII) to (XVI) is contained, the total amount is 3 to 2
It is preferable to contain it in the range of 5% by weight.
The compound (XII) is preferably contained in the range of 3 to 25% by weight.

The liquid crystal composition of the present invention is preferably used, for example, in the following composition according to the purpose of use. For the purpose of particularly lowering the crystal phase or smectic phase-nematic phase transition temperature T → _N of the liquid crystal composition, (1) the compound of the general formula (I) and (2) the compound of the general formulas (II) to (IV) The compound selected from the group consisting of is preferably used in combination, and for the purpose of further lowering T → _N ,
(3) Compounds selected from the group consisting of compounds of the general formulas (VI) to (VII) are preferably used in combination, and further selected from the group consisting of compounds of the general formulas (IX) to (XI). It is preferable to use the compounds in combination.

For the purpose of increasing the nematic phase-isotropic liquid phase transition temperature T _NI of the liquid crystal composition and decreasing the crystal phase or smectic phase-nematic phase transition temperature T → _N ,
(1) compounds of general formula (I) and (2) general formulas (II) to (IV)
It is preferable to use a combination of compounds selected from the group consisting of the above compounds, and it is more preferable to use a compound selected from the group consisting of the compounds of (3) the general formulas (X) to (XI) in combination.

For the purpose of lowering the threshold voltage V _th of liquid crystal display, (1) the compound of the general formula (I), (2) the general formula (II)
To (III), a compound selected from the group consisting of compounds and (3) a compound of general formula (V) are preferably used in combination, and further (4) a group consisting of compounds of general formulas (IX) to (XI) It is preferable to use a combination of compounds selected from

For the purpose of speeding up the response characteristic of the liquid crystal display,
It is preferable to use the compound of the general formula (I), the compound of the general formula (II), the compound of the general formula (II), and the compound of the general formula (VI), in combination with the compound of the general formula (4). ) To (XVI) are preferably used in combination with a compound selected from the group consisting of compounds.

The birefringence Δn of the liquid crystal composition is 0.07 to
For the purpose of adjusting to the range of 0.08, (1) general formula (I)
It is preferable to use a compound selected from the group consisting of compounds of (2) general formulas (III) to (V) and a compound of (3) general formula (VII) in combination. For the purpose of adjusting Δn in the range of 0.08 to 0.10, (1) the compound of general formula (I), (2) the compound of general formula (II) and (3) the general formula (VI) It is preferable to use a combination of compounds, and moreover, general formula (4), general formulas (X) to (XI)
It is preferable to use a combination of compounds selected from the group consisting of

The liquid crystal composition of the present invention thus obtained has a nematic phase-isotropic liquid phase transition temperature (T _NI ) in the range of 80 to 100 ° C., as shown in Examples described later. And the threshold voltage (V _th ) is 1.2 to 1.6
Those in the range of V are obtained, or the nematic phase-
The isotropic liquid phase transition temperature (T _NI ) is in the range of 100 to 120 ° C., and the threshold voltage (V _th ) is 1.6 to
Those having a range of 2.0 V are obtained, and these nematic liquid crystal compositions have a crystal phase or a smectic phase-nematic phase transition temperature (T → _N ) of −10 ° C. or less and a birefringence Δn of 0. It is in the range of 0.07-0.10 and the dielectric anisotropy (Δε) is + 6-9, which is very practical.
It was possible to obtain the one that almost satisfied the required characteristics.

The nematic liquid crystal composition of the present invention is
As shown in the examples described below, a heating acceleration test and an ultraviolet irradiation acceleration test were performed, and after each acceleration test, 9
It was confirmed that it has a high voltage holding ratio of 8% or more and that it is chemically stable and has a high resistance value.

Therefore, the liquid crystal display device using such a nematic liquid crystal composition also has very excellent characteristics, and the present invention also provides a liquid crystal display device using the above-mentioned various nematic liquid crystal compositions. To do.

The liquid crystal display device of the present invention, especially active
The matrix type liquid crystal display device or the twisted nematic or super twisted nematic liquid crystal display device exhibits liquid crystallinity in a wide temperature range, has a low threshold voltage, and has a sufficiently high voltage holding ratio. Especially in the active matrix liquid crystal display device, TN-LCD and STN-LC have excellent contrast without flicker.
It was confirmed that the D liquid crystal display device can display at a wide range of driving frequencies.

[0086]

The present invention will be described in detail below with reference to examples.
The invention is not limited to these examples. Further, "%" in the compositions of the following examples is "% by weight"
Means

The specific resistance of the composition is 2 g of the liquid crystal composition.
In an ampoule tube, degassed in vacuum, and then nitrogen-filled and sealed, 180 ° C, 1 hour heating acceleration test, and 1
The specific resistance of the liquid crystal composition after the 0-hour ultraviolet irradiation acceleration test “SUNTEST” (manufactured by Original Hanau) was measured.

In addition, the meaning of each symbol of the measured characteristics in the examples is as follows. T _NI : Nematic phase-isotropic liquid phase transition temperature (° C) T → _N : Crystal phase or smectic phase-nematic phase transition temperature (° C) V _th : Panel liquid crystal layer thickness d, first minimum Δn Threshold voltage (V) when configuring a TN-LCD with d = 0.5 Δε: Dielectric anisotropy Δn: Birefringence τr = τd: Light is applied when voltage is applied from no voltage applied A response time (msec) in which the rise time τr until the light is transmitted becomes equal to the fall time τd until the light is no longer transmitted except the voltage from the voltage applied state.

(Example 1)

[0090]

[Chemical formula 22]

A nematic liquid crystal composition (3-1) comprising
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 82.0 ° C. T → _N : −32.0 ° C. V _th : 1.37 V Δε: 9.2 Δn: 0.076 Specific resistance before test: 7.5 × 10 ¹³ Ω c
Specific resistance after m heating acceleration test: 5.6 × 10 ¹³ Ω c
m Specific resistance after UV irradiation acceleration test: 3.0 × 10 ¹³ Ω c
m Voltage holding ratio before test: 99.6% (Measuring temperature 80 ° C) Voltage holding ratio after heating acceleration test: 98.7% (Measuring temperature 80 ° C) Voltage holding ratio after ultraviolet irradiation acceleration test: 98.3% ( (Measurement temperature 80 ℃)

When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-1) as a constituent material was produced, it was confirmed that the leakage current was small and flicker did not occur.

(Example 2)

[0094]

[Chemical formula 23]

A nematic liquid crystal composition (3-2) consisting of
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 85.7 ° C. T → _N : −25.0 ° C. V _th : 1.42 V Δε: 7.4 Δn: 0.074

(Example 3)

[0097]

[Chemical formula 24]

A nematic liquid crystal composition (3-3) consisting of
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 93.2 ° C. T → _N : −30.0 ° C. V _th : 1.60 V Δε: 7.2 Δn: 0.080

(Example 4)

[0100]

[Chemical 25]

A nematic liquid crystal composition consisting of (3-4)
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 92.1 ° C. T → _N : <−70.0 ° C. V _th : 1.58 V Δε: 6.5 Δn: 0.084

(Example 5)

[0103]

[Chemical formula 26]

A nematic liquid crystal composition (3-5) consisting of
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 119.3 ° C. T → _N : <−70.0 ° C. V _th : 1.63 V Δε: 7.3 Δn: 0.091 τr = τd: 29.0 msec

(Example 6)

[0106]

[Chemical 27]

A nematic liquid crystal composition (3-6) consisting of
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 124.5 ° C. T → _N : <−70.0 ° C. V _th : 2.00 V Δε: 7.0 Δn: 0.093 Specific resistance before test: 7.0 × 10 ¹³ Ω c
m Specific resistance after accelerated heating test: 5.8 × 10 ¹³ Ω c
m Specific resistance after UV irradiation acceleration test: 2.7 × 10 ¹³ Ω c
m Voltage holding ratio before test: 99.8% Voltage holding ratio after heating accelerated test: 98.6% Voltage holding ratio after ultraviolet irradiation accelerated test: 97.5%

When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-6) as a constituent material was produced, it was confirmed that the leakage current was small and flicker did not occur.

(Example 7)

[0110]

[Chemical 28]

A nematic liquid crystal composition consisting of (3-7)
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 98.6 ° C. T → _N : <−70.0 ° C. V _th : 1.73 V Δε: 6.0 Δn: 0.087 Specific resistance before test: 7.2 × 10 ¹³ Ω c
Specific resistance after m heating acceleration test: 5.5 × 10 ¹³ Ω c
m Specific resistance after UV irradiation acceleration test: 3.2 × 10 ¹³ Ω c
m Voltage holding ratio before test: 99.0% Voltage holding ratio after heating accelerated test: 97.8% Voltage holding ratio after ultraviolet irradiation accelerated test: 97.3%

When an active matrix liquid crystal display device using the nematic liquid crystal composition (3-7) as a constituent material was produced, it was confirmed that the leakage current was small and flicker did not occur.

Further, this nematic liquid crystal composition (3-
A chiral substance “S-811” (manufactured by Merck) was added to 7) to prepare a mixed liquid crystal. On the other hand, an organic film of "SAN EVER 150" (manufactured by Nissan Kagaku Co., Ltd.) is rubbed on the opposing flat transparent electrodes to form an alignment film, and STN-L with a twist angle of 220 degrees is formed.
A cell for CD display was produced. The above-mentioned mixed liquid crystal was injected into this cell to construct a liquid crystal display device, and display characteristics were measured.
As a result, the threshold voltage is low, high time division characteristics are excellent,
ST with improved display screen flickering and crosstalk
A liquid crystal display device having N-LCD display characteristics was obtained.

(Embodiment 8)

[0115]

[Chemical 29]

A nematic liquid crystal composition consisting of (3-8)
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 83.0 ° C. V _th : 1.29 V Δε: 8.6 Δn: 0.076

(Example 9)

[0118]

[Chemical 30]

A nematic liquid crystal composition (3-9) consisting of
Was prepared and various properties of this composition were measured. The results were as follows. T _NI : 84.3 ° C. V _th : 1.30 V Δε: 8.8 Δn: 0.077

(Embodiment 10)

[Chemical 31]

A nematic liquid crystal composition (3-1
0) was prepared and various properties of this composition were measured.
The results were as follows. T _NI : 89.3 ° C. T → _N : −45.0 ° C. V _th : 1.48 V Δε: 7.9 Δn: 0.088

(Embodiment 11)

[0123]

[Chemical 32]

A nematic liquid crystal composition (3-1
1) was prepared and various properties of this composition were measured.
The results were as follows. T _NI : 83.3 ° C. T → _N : <−70.0 ° C. V _th : 1.32 V Δε: 8.7 Δn: 0.082

[0125]

The nematic liquid crystal composition of the present invention exhibits a nematic phase in a wide temperature range, has a low threshold voltage,
It has a high voltage holding ratio and high chemical stability. Therefore, the liquid crystal display device of the present invention using this can improve the flickering of the display screen and the crosstalk phenomenon,
Good drive characteristics and display characteristics can be obtained in TN-LCD, STN-LCD or active matrix method with a large amount of information.

Claims (35)

[Claims] 1. A general formula (I): (Wherein R ¹ represents a linear alkyl group having 2 to 7 carbon atoms) and (2) general formula (II) to
(III) [Chemical formula 2] (Wherein R ² represents a linear alkenyl group having 2 to 7 carbon atoms, and R ³ represents a linear alkyl group having 2 to 7 carbon atoms). A nematic liquid crystal composition containing a compound described below. 2. The nematic liquid crystal composition according to claim 1, containing a compound represented by the general formula (II). 3. The nematic liquid crystal composition according to claim 2, containing a compound represented by the general formula (III). 4. A compound represented by the general formula (I) according to claim 1 and (2) general formulas (IV) to (V): (In the formula, each R ⁴ independently represents a linear alkyl group having 2 to 7 carbon atoms.) A nematic liquid crystal composition containing a compound selected from the group consisting of compounds Stuff. 5. A compound selected from the group consisting of (1) a compound represented by the general formula (I), (2) a compound represented by the general formula (II) to (III) according to claim 1, and (3) A nematic liquid crystal composition comprising a compound selected from the group consisting of compounds represented by the general formulas (IV) to (V) according to claim 4. 6. A nematic liquid crystal composition according to claim 5, containing the compound represented by the general formula (II) according to claim 1 and the compound represented by the general formula (V) according to claim 4. Stuff. 7. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II) and a compound represented by the general formula (V) according to claim 4. The nematic liquid crystal composition according to claim 6. 8. A compound represented by the general formula (II) according to claim 1, a compound represented by the general formula (III) and claim 4.
6. The nematic liquid crystal composition according to claim 5, containing the compound represented by the general formula (V). 9. A compound represented by the general formula (I), a compound represented by the general formula (II), and a general formula (III) according to claim 1.
9. The nematic liquid crystal composition according to claim 8, comprising a compound represented by the formula (4) and a compound represented by the general formula (V) according to claim 4. 10. General formulas (VI) to (XI): (In the formula, R ⁵ represents a linear alkenyl group having 2 to 7 carbon atoms, and R ⁶ independently represents 2 to 7 carbon atoms.
Represents a straight chain alkyl group, X ¹ independently represents H or F, and r represents 0 or 1. 9. A nematic liquid crystal composition according to claim 1, which contains a compound selected from the group consisting of compounds represented by 11. A compound selected from the group consisting of compounds represented by general formulas (VI) to (VII) and general formulas (IX) to (X).
11. The nematic liquid crystal composition according to claim 10, containing a compound selected from the group consisting of compounds represented by: 12. A compound represented by the general formula (II) according to claim 1, a compound represented by the general formula (VI) according to claim 10, a compound represented by the general formula (VII) and a general formula (X). A compound containing a compound represented by:
The nematic liquid crystal composition according to item 1. 13. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), and
13. The nematic liquid crystal composition according to claim 12, comprising the compound represented by the general formula (VI), the compound represented by the general formula (VII) and the compound represented by the general formula (X). 14. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), and
The compound represented by the general formula (VI), the compound represented by the general formula (VII), the compound represented by the general formula (IX) and the compound represented by the general formula (X). 11. The nematic liquid crystal composition according to item 11. 15. The nematic liquid crystal composition according to claim 10, containing the compound represented by the general formula (VI) according to claim 10. 16. A compound represented by the general formula (I), a compound represented by the general formula (II), and a general formula (II) according to claim 1.
The compound represented by I) and the general formula (VI) according to claim 10.
A compound represented by the formula 1.
The nematic liquid crystal composition according to item 5. 17. The nematic liquid crystal composition according to claim 10, containing a compound represented by the general formula (VII). 18. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), and
18. The nematic liquid crystal composition according to claim 17, which comprises a compound represented by the general formula (VII). 19. The nematic liquid crystal composition according to claim 10, which contains a compound selected from the group consisting of compounds represented by formulas (VIII) to (XI). 20. The compound represented by the general formula (VIII), the compound represented by the general formula (IX), and the general formula according to claim 10.
20. The nematic liquid crystal composition according to claim 19, containing a compound represented by (X) and a compound represented by the general formula (XI). 21. The compound represented by the general formula (I), the compound represented by the general formula (II), or the general formula (II) according to claim 1.
A compound represented by formula (I), a compound represented by formula (V) according to claim 4, a compound represented by formula (VIII) according to claim 10, a compound represented by formula (IX), a formula
The nematic liquid crystal composition according to claim 20, comprising a compound represented by formula (X) and a compound represented by formula (XI). 22. General formulas (XII) to (XVI): (In the formula, R ^7's each independently represent a linear alkyl group or alkenyl group having 2 to 7 carbon atoms, and R ^8's each independently represent a linear alkyl group having 2 to 7 carbon atoms. Represents an alkenyl group, an alkoxy group or an alkenyloxy group, and each R ⁹ independently has 2 to 2 carbon atoms.
7 represents a linear alkyl group. And a compound selected from the group consisting of compounds represented by the formula (1), (2), (3), (4), (5), (6)
The nematic liquid crystal composition according to 12, 14, 15, 17, 19 or 20. 23. The nematic liquid crystal composition according to claim 22, containing a compound represented by the general formula (XII). 24. A compound represented by the general formula (II) according to claim 1, a compound represented by the general formula (VI) according to claim 10, a compound represented by the general formula (IX), and a general formula (X). 23. A compound represented by the formula (21) and a compound represented by the general formula (XII) according to claim 21.
The described nematic liquid crystal composition. 25. A compound represented by the general formula (I) according to claim 1, a compound represented by the general formula (II), and
A compound represented by the general formula (VI), a compound represented by the general formula (IX), a compound represented by the general formula (X), and a compound represented by the general formula (XII) according to claim 21. 25. The nematic liquid crystal composition according to claim 24. 26. The nematic liquid crystal composition according to claim 1, wherein the content of the compound represented by the general formula (I) according to claim 1 is in the range of 3 to 60% by weight. 27. The general formulas (II) and (III) according to claim 1.
27. The nematic liquid crystal composition according to claim 26, wherein the total amount of the compounds selected from the group consisting of the compounds is represented by 3 to 50 wt%. 28. The content of the compound represented by the general formula (II) according to claim 1 in the range of 0 to 25% by weight, and the content of the compound represented by the general formula (III) according to claim 1 The nematic liquid crystal composition according to claim 27, wherein the content is in the range of 0 to 30% by weight. 29. The content of the compound selected from the group consisting of the compounds represented by the general formulas (IV) to (V) according to claim 4 is in the range of 3 to 40% by weight in total. 29. The nematic liquid crystal composition according to claim 26, 27 or 28. 30. The nematic liquid crystal composition according to claim 29, wherein the content of the compound represented by the general formula (V) according to claim 4 is in the range of 3 to 30% by weight. 31. The general formulas (VI) to (VII) according to claim 10.
31. The nematic liquid crystal composition according to claim 26, 27, 28, 29 or 30, wherein the total content of the compounds selected from the group consisting of the compounds represented by the formulas is in the range of 3 to 55% by weight. 32. The general formulas (XII) to (XVI) according to claim 22.
The nematic liquid crystal composition according to claim 26, 27, 28, 29, 30 or 31, characterized in that the content of the compound selected from the group consisting of the compounds is in the range of 3 to 25% by weight. Stuff. 33. The nematic liquid crystal composition according to claim 32, wherein the content of the compound represented by the general formula (XII) according to claim 22 is in the range of 3 to 25% by weight. 34. An active matrix liquid crystal display device using the nematic liquid crystal composition according to claim 1. 35. A twisted nematic or super twisted nematic liquid crystal display device using the nematic liquid crystal composition according to claim 1.