TWI731141B - Liquid crystal composition of negative monomer containing cyclopentyl cyclohexene group and liquid crystal display element thereof - Google Patents

Abstract

本發明公開的液晶組合物，性能優異，光學各向異性在0.080~0.150範圍內，並且具有低的旋轉黏度、較快的反應時間、和良好的化學、光、熱穩定性，非常適用於製造液晶顯示元件，尤其適合於主動矩陣顯示元件，如使用VA、FFS或IPS模式的主動矩陣顯示器。 The invention discloses a liquid crystal composition and a display element using the liquid crystal composition. The liquid crystal composition contains one or more compounds of general formula I, general formula II, and general formula III.

The liquid crystal composition disclosed by the present invention has excellent performance, optical anisotropy in the range of 0.080 to 0.150, low rotational viscosity, fast reaction time, and good chemical, optical and thermal stability, and is very suitable for manufacturing Liquid crystal display elements are particularly suitable for active matrix display elements, such as active matrix displays using VA, FFS or IPS modes.

Description

Liquid crystal composition of negative monomer containing cyclopentyl cyclohexene group and its liquid crystal Display element

The invention of this application belongs to the field of liquid crystal compounds, and specifically relates to a negative dielectric anisotropy liquid crystal composition and a liquid crystal display element using the liquid crystal composition.

Display is the process of converting electrical signals (data information) into visible light (visual information). The device that completes the display is the Man-Machine Interface (MMI). Flat Panel Display (FPD) is currently the most popular A type of display device. Liquid Crystal Display (LCD) is the first product developed and commercialized in FPD. At present, Thin Film Transistor Liquid Crystal (TFT-LCD) has become a mainstream product in LCD applications.

The development of TFT-LCD has gone through a long stage of basic research. After the realization of mass production and commercialization, TFT-LCD products have become more and more widely used due to their advantages of lightness, thinness, environmental protection, and high performance. Whether it is a small-sized mobile phone screen, a large-sized notebook PC (Notebook PC) or monitor (Monitor), and a large-scale liquid crystal TV (LCDTV), TFT-LCD applications can be seen everywhere. Early commercial TFT-LCD products basically adopted a twisted nematic (TN) display mode. The biggest problem is that the viewing angle is not large enough. With the increase in the size of TFT-LCD products, especially the application of TFT-LCD in the TV field, in-plane switching (In-Plane Swiching, IPS) display mode was developed and used. The IPS display mode was first published in a paper by American R. Soref in 1974, and it was proposed by the German G. Baur to apply IPS as a wide viewing angle technology in TFT-LCD. In 1995, Hitachi of Japan developed the world's first 13.3-inch IPS mode wide viewing angle TFT-LCD product. Hyundai Corporation of South Korea has developed Fringe Field Switching (FFS) display mode TFT-LCD products based on IPS.

TFT-LCD is a liquid crystal display device controlled by a TFT switch. The electrical and optical characteristics of the liquid crystal directly affect the display effect. Different types of liquid crystals have different electrical and optical characteristics and different display modes. The performance parameters that have a greater impact on the liquid crystal materials used in TFT-LCD include: operating temperature range, driving voltage, response speed, contrast, hue, gradation, viewing angle, etc., among which the driving voltage is affected by dielectric anisotropy and elastic coefficient The effect is greater. The viscosity and elastic coefficient affect the reaction speed of the liquid crystal material, and the phase difference and refractive index anisotropy affect the color tone of the liquid crystal display. In the past, those cyano-containing compounds could not meet these conditions, and only fluorine-containing liquid crystal materials could be suitable for making TFT-LCDs.

In addition, one type of liquid crystal molecule cannot meet all the requirements of TFT-LCD display, and a combination of multiple liquid crystal molecules must be carried out. Various physical property requirements of liquid crystal materials can be achieved by combining a variety of liquid crystal molecules. These requirements mainly include 1) high stability. 2) Moderate birefringence. 3) Low viscosity. 4) Larger dielectric anisotropy. 5) Wide temperature range. The ideal storage temperature range is -40℃~100℃. Generally, for special applications such as vehicle display, the temperature may be expanded to -40℃~110℃.

Nowadays, LCD product technology is very mature, successfully solving technical difficulties such as viewing angle, resolution, color saturation and brightness, and its display performance has approached or exceeded CRT displays. Large-size and medium- and small-size LCDs have gradually occupied the mainstream status of flat panel displays in their respective fields. In order to pursue higher performance specifications, speeding up the response time has become the goal pursued by various device manufacturers.

Specifically, the reaction time of the liquid crystal is limited by the rotational viscosity γ 1/elastic constant K of the liquid crystal. Therefore, considering the liquid crystal material, it is necessary to find ways to reduce the rotational viscosity γ 1 of the liquid crystal medium while increasing the elastic constant K to speed up Reaction time. In actual research, it is found that the rotational viscosity and the elastic constant are a pair of contradictory parameters. Reducing the rotational viscosity will also cause a decrease in the elastic constant, failing to achieve the goal of reducing the response time. From the device aspect, the goal of speeding up the reaction time can be achieved by reducing the cell thickness d, and this is easy to achieve, but since the retardation of the device △nd is fixed, then reducing the cell thickness d requires an increase in the liquid crystal material. Its optical anisotropy is △n.

Therefore, in order to meet the above requirements, it is necessary to develop a series of compounds with superior performance to solve the problem of slow response time of liquid crystal displays.

In view of the patent problems of the existing negative liquid crystal compounds of the cyclohexene group of the alkyl end groups and the technical problems of the low refractive index of the negative liquid crystal compounds of the cyclohexane group containing the cyclopentyl substituent, the present invention intends The invention provides a liquid crystal medium of a negative liquid crystal compound containing a cyclopentyl cyclohexene group. The optical anisotropy of the liquid crystal composition is in the range of 0.080~0.150, has a wide nematic temperature range, good low temperature performance, and has good mutual solubility, and also has good light and thermal stability, and also has Low rotational viscosity, faster response time, suitable for high-performance display components. The term "display component" in this article covers the general term "display, display device, etc.".

其中，R₁、R₂、R₃、R₄、R₅各自獨立地表示碳原子數為1-5的烷基、碳原子數為1-5的烷氧基、碳原子數為2-5的鏈烯基，所述R₄、R₅所示基團中任一個CH₂可以被碳原子數為3-5的伸環烷基替代；m表示1或2，n表示1或2；Z表示單鍵、-COO-、-CH₂O-或-CH₂CH₂-；

、

表示

及/或

；

表示

、

、

、

、

、

或

In order to solve the above-mentioned technical problems, the technical solution adopted by the present invention is: the present invention provides a liquid crystal composition, which comprises a first component composed of one or more compounds represented by general formula I, and is composed of one or more general formula II The second component composed of the compounds shown and the third component composed of one or more compounds represented by the general formula III,

Wherein, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ each independently represent an alkyl group having 1-5 carbon atoms, an alkoxy group having 1-5 carbon atoms, and 2-5 carbon atoms. alkenyl, said R _4, R ₅ in the group represented by any one of the CH ₂ can be of 3-5 carbon atoms, a cycloalkyl group extending alternatively; m represents 1 or 2, n represents 1 or 2; Z Represents a single bond, -COO-, -CH ₂ O- or -CH ₂ CH ₂ -;

,

Means

And/or

；

Means

,

,

,

,

,

or

Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is that: the present invention discloses a negative dielectric anisotropy liquid crystal medium, which has excellent performance, optical anisotropy in the range of 0.080 to 0.150, and has a low Rotational viscosity, fast reaction time, appropriate negative dielectric anisotropy and good low-temperature reliability are very suitable for the manufacture of VA mode liquid crystal display elements, especially suitable for active matrix display elements, such as the use of FFS or IPS, Active matrix displays with MVA, PVA, PSVA, and UV2A effects.

The compound represented by the general formula I provided by the present invention, due to the introduction of a cyclopentyl substituent, not only avoids the patent problem of the negative liquid crystal compound whose terminal group is an alkyl group, but also improves its clarity point and K33 value at the same time; In addition, the introduction of cyclohexene groups increases the refractive index of negative liquid crystal compounds compared to cyclohexane groups. Therefore, the liquid crystal medium containing the liquid crystal compound represented by the general formula I has a high sharp point, a large dielectric anisotropy, a large K33 value and a high refractive index. It is precisely because the liquid crystal compound represented by the general formula I has such advantages, it will become the required liquid crystal compound for the liquid crystal medium for active matrix display elements in the future.

The dielectrically neutral compound represented by the general formula II provided by the present invention generally has a smaller viscosity and good mutual solubility. According to actual needs, an appropriate amount of the compound of general formula II can be added to adjust the various characteristics of the liquid crystal medium.

The dielectric negative compound represented by the general formula III provided by the present invention and the compound with a linear alkyl group at the end can be used to reduce the pretilt angle of the liquid crystal, so as to improve the black state of the liquid crystal, increase the contrast, and adjust the liquid crystal characteristics. Order to improve the residual image level of liquid crystals in display devices; compounds with linear alkenyl groups at the end have a large K value, after power off, due to their own elastic constant, can indirectly increase their reaction time The fall time.

The further improvement of the technical scheme of the present invention is that: in the liquid crystal composition, the mass percentage of the first component is 1 to 55%, the mass percentage of the second component is 1 to 55%, and the third component is The mass percentage content of 1~50%.

所述通式Ⅱ所示化合物具體為式Ⅱ1~Ⅱ5所示化合物，

所述通式Ⅲ所示化合物具體為式Ⅲ1~Ⅲ20所示化合物，

其中，r表示1~5的整數；R₂、R₃、R₄、R₅各自獨立地表示碳原子數為1-5的烷基、碳原子數為1-5的烷氧基、碳原子數為2-5的鏈烯基，所述R₄、R₅所示基團中任一個CH₂可以被碳原子數為3-5的伸環烷基替代。 A further improvement of the technical scheme of the present invention is that: the compound represented by the general formula I is specifically the compound represented by the formula I1 to I3,

The compound represented by the general formula II is specifically the compound represented by the formula II1 to II5,

The compound represented by the general formula III is specifically the compound represented by formula III1 to III20,

Wherein, r represents an integer of 1 to 5; R ₂ , R ₃ , R ₄ , and R ₅ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a carbon atom For the alkenyl group with the number of 2-5 _{, any CH 2 of the groups represented by R 4} and R ₅ can be replaced by a cycloalkylene group with a carbon number of 3-5.

Preferably, the compound represented by the general formula I is specifically the compound represented by the formula I1-1 to I3-10,

Preferably, the compound represented by the general formula II is specifically the compound represented by the formula II1-1 to II5-4,

Preferably, the compound represented by general formula III is specifically the compound represented by formula III1-1 to III17-3,

其中，R₆表示碳原子數為1~5的直鏈烷基，其中任一個CH₂可以被碳原子數為3-5的伸環烷基替代；R₇表示碳原子數為1~5的直鏈烷基。 A further improvement of the technical scheme of the present invention is that the liquid crystal composition further comprises a fourth component composed of one or more compounds represented by the general formula IV, and the mass percentage of the fourth component in the liquid crystal composition is 1 ~30%,

Among them, R ₆ represents a linear alkyl group with 1 to 5 carbon atoms, and any CH ₂ can be replaced by a cycloalkylene group with 3 to 5 carbon atoms _{; R 7 represents a straight chain alkyl group with 1 to 5 carbon atoms} Straight chain alkyl.

其中，R₆表示碳原子數為1~5的直鏈烷基，其中任一個CH₂可以被碳原子數為3-5的伸環烷基替代。 A further improvement of the technical scheme of the present invention is that the compound represented by the general formula IV is specifically the compound represented by the formula IV1 to IV8,

Wherein, R ₆ represents a straight-chain alkyl group having 1 to 5 carbon atoms, and any CH ₂ can be replaced by a cycloalkylene group having 3 to 5 carbon atoms.

Preferably, the compound represented by formula IV is specifically the compound represented by formula IV1-1 to IV5-1,

其中，R₈、R₉各自獨立地表示碳原子數為1-5的烷基、碳原子數為1-5的烷氧基、碳原子數為2-5的鏈烯基，所述R₈、R₉所示基團中任一個CH₂可以被碳原子數為3-5的伸環烷基替代；W表示O或S。 A further improvement of the technical scheme of the present invention is that the liquid crystal composition further comprises a fifth component composed of one or more compounds represented by the general formula V, and the mass percentage of the fifth component in the liquid crystal composition is 1 ~15%,

Wherein, R ₈ and R ₉ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an alkenyl group having 2 to 5 carbon atoms. The R _{8 , Any CH 2} in the group represented by R ₉ can be replaced by a cycloalkylene group having 3 to 5 carbon atoms; W represents O or S.

A further improvement of the technical scheme of the present invention is that the compound represented by the general formula V is specifically the compound represented by formula V1 to V2,

其中，R₈、R₉各自獨立地表示碳原子數為1-5的烷基、碳原子數為1-5的烷氧基、碳原子數為2-5的鏈烯基，所述R₈、R₉所示基團中任一個CH₂可以被碳原子數為3-5的伸環烷基替代；較佳地，所述通式Ⅳ所示化合物具體為式Ⅴ1-1~Ⅴ2-2所示化合物，

Wherein, R ₈ and R ₉ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an alkenyl group having 2 to 5 carbon atoms. The R _{8 , Any CH 2} in the group represented by R ₉ can be replaced by a cycloalkylene having 3 to 5 carbon atoms; preferably, the compound represented by the general formula IV is specifically the formula Ⅴ1-1~Ⅴ2-2 The compound shown,

其中，R₁₀、R₁₁各自獨立地表示碳原子數為1-5的烷基、碳原子數為1-5的烷氧基、碳原子數為2-5的鏈烯基，所示R₁₀、R₁₁所示基團中任一個CH₂可以碳原子數為3-5的伸環烷基替代。 A further improvement of the technical scheme of the present invention is that the liquid crystal composition further comprises a sixth component composed of one or more compounds represented by the general formula VI, and the mass percentage of the sixth component in the liquid crystal composition is 1 ~15%,

Wherein, R ₁₀ and R ₁₁ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and an alkenyl group having 2 to 5 carbon atoms, as R ₁₀ , _{Any CH 2} in the group represented by _{R 11} can be replaced by a cycloalkylene group with 3 to 5 carbon atoms.

R₁₁₁表示碳原子數為1-5的烷氧基。 Preferably, the compound represented by formula IV is specifically the compound represented by formula VI1 and VI2,

R ₁₁₁ represents an alkoxy group having 1 to 5 carbon atoms.

The present invention also discloses a liquid crystal display element comprising the above-mentioned negative dielectric anisotropic liquid crystal composition, and the display element is an active matrix display element or a passive matrix display element.

Due to the adoption of the above technical solution, the technical progress of the present invention is that: the liquid crystal medium disclosed in the present invention has excellent performance, optical anisotropy in the range of 0.080~0.150, and has low rotational viscosity, faster reaction time, and good The chemical, optical, and thermal stability of the product is very suitable for the manufacture of liquid crystal display elements, especially for active matrix display elements, such as active matrix displays using VA, FFS or IPS modes.

In detail, the liquid crystal composition disclosed in the present invention has low viscosity, good compatibility with other liquid crystal compounds, and has an appropriate size of optical anisotropy and dielectric constant anisotropy for use in liquid crystal displays In the case of an element, a liquid crystal composition having a rapid response characteristic and a liquid crystal display element containing the liquid crystal composition.

The liquid crystal composition disclosed in the present invention, with different proportions of the components, will show slightly different properties, such as dielectric anisotropy △ ε , optical anisotropy △n, and the transformation temperature of the nematic phase of liquid crystal into liquid The point CP and the stability at low temperature will be different, which can be applied to different types of display elements, but the same feature is that its rotational viscosity γ 1 is low. Applied to liquid crystal display elements, quick response can be achieved.

The present invention will be further described in detail below in conjunction with the examples: The parts involved in the following examples are percentages by weight, and the temperature unit is °C. The specific meanings and test conditions of other symbols are as follows: SN represents the crystalline state of the liquid crystal. The melting point of nematic phase (℃); Cp represents the clear point of liquid crystal (℃), the test instrument: Mettler-Toledo-FP System microthermal analyzer; γ 1 is the rotational viscosity (mPa·s), the test condition is: 25 ℃, INSTEC: ALCT-IR1, 20-micron parallel box or 18-micron vertical box; K11 is the torsional elastic constant, K33 is the splay elastic constant, the test conditions are: 25℃, INSTEC: ALCT-IR1, 20-micron parallel box or 18 vertical micron cartridge; △ ε represents dielectric anisotropy, △ ε = ε ∥ -ε⊥, wherein, ε∥ is a dielectric constant parallel to the molecular axis, ε ⊥ is the dielectric constant in the molecular axis, perpendicular to the test conditions : 25℃, INSTEC: ALCT-IR1, 20-micron parallel box or 18-micron vertical box; △n represents optical anisotropy, △n=no-ne, where no is the refractive index of ordinary light, and ne is extraordinary light Test conditions: 589nm, 25±0.2°C; the following examples 1 to 6 respectively weigh the liquid crystal compounds in proportion to prepare liquid crystal media. The various liquid crystal monomers used can be synthesized by well-known methods or obtained by commercial channels.

The equipment and instruments used to prepare the liquid crystal medium are:

(1) Electronic precision balance (precision 0.1mg)

(2) Stainless steel beaker: used for weighing liquid crystal

(3) Spoon: used to add monomer

(4) Magnet: used for stirring

(5) Temperature control electromagnetic stirrer

The preparation method of the liquid crystal medium includes the following steps: (1) Put the monomers in order in order; (2) Place the stainless steel beaker on the balance, and use a small spoon to put the monomers into the stainless steel beaker; (3) Add the monomer liquid crystal according to the required weight in sequence; 4) Put the added stainless steel beaker on a magnetic stirring instrument and heat it to melt; (5) After most of the mixture in the stainless steel beaker is melted, add a magnet to the stainless steel beaker, stir the liquid crystal mixture evenly, and cool it to the room After warming, the liquid crystal medium is obtained.

The structure of the liquid crystal monomer in the application examples of the present invention is expressed by codes, and the code expression methods of the liquid crystal ring structure, end groups, and connecting groups are shown in the following table (1) and table (2)

表示為3CCV1，

表示為3CCOYO2。 E.g:

Expressed as 3CCV1,

Expressed as 3CCOYO2.

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8

Comparative Example 1 of Example 8

Comparative Example 2 of Example 8

Comparative Example 3 of Example 8

Comparative Example 4 of Example 8

Comparative Example 5 of Example 8

It can be seen from the comparative example in Example 8 that the liquid crystal composition of the present invention has a higher refractive index and a lower rotational viscosity γ 1 than cyclopentyl and alkyl CY and alkyl LY. The base CLY has a lower refractive index and a sharp point, but its rotational viscosity γ 1 is particularly low. The liquid crystal composition of the present invention can be used for liquid crystal displays to achieve rapid response, and is especially suitable for VA, IPS, and FFS modes. Liquid crystal material.

Claims (9)

A liquid crystal composition comprising a first component composed of one or more compounds represented by general formula I, a second component composed of one or more compounds represented by general formula II, and one or more general formula III A third component of the compound shown:

Wherein, R ₁ , R ₂ , R ₃ , R ₄ , and R ₅ each independently represent an alkyl group having 1-5 carbon atoms, an alkoxy group having 1-5 carbon atoms, or 2-5 carbon atoms In the alkenyl group, _{any CH 2 of the groups represented by R 4} and R ₅ can be replaced by a cycloalkylene group with a carbon number of 3-5; m represents 1 or 2, n represents 1 or 2; Z represents a single Bond, -COO-, -CH ₂ O- or -CH ₂ CH ₂ -;

,

Means

And/or

；

Means

,

,

,

,

,

The liquid crystal composition according to claim 1, wherein the mass percentage of the first component is 1-30%, and the mass percentage of the second component is 10-65%. And the mass percentage of the third component is 1-50%. The liquid crystal composition according to claim 1, wherein the compound represented by the general formula I is the compound represented by the formula I1 to I3:

The compound represented by the general formula II is the compound represented by the formula II1~II5:

The compound represented by the general formula III is the compound represented by formula III1~III17:

Wherein, r represents an integer of 1 to 5; R ₂ , R ₃ , R ₄ , and R ₅ each independently represent an alkyl group with 1 to 5 carbon atoms, an alkoxy group with 1 to 5 carbon atoms, or a carbon atom For the alkenyl group with the number of 2-5 _{, any CH 2 of the groups represented by R 4} and R ₅ can be replaced by a cycloalkylene group with a carbon number of 3-5. The liquid crystal composition according to claim 1, further comprising a fourth component composed of one or more compounds represented by the general formula IV, and the mass percentage of the fourth component is 1-30%:

Among them, R ₆ represents a straight-chain alkyl group with 1 to 5 carbon atoms, and any CH ₂ can be replaced by a cycloalkylene group with 3 to 5 carbon atoms _{; R 7 represents a straight chain alkyl group with 1 to 5 carbon atoms} Straight chain alkyl. The liquid crystal composition according to claim 4, wherein the compound represented by the general formula IV is the compound represented by the formula IV1 to IV5:

Wherein, R ₆ represents a straight-chain alkyl group having 1 to 5 carbon atoms, and any CH ₂ can be replaced by a cycloalkylene group having 3 to 5 carbon atoms. The liquid crystal composition according to claim 1, further comprising a fifth component composed of one or more compounds represented by the general formula V, and the mass percentage of the fifth component is 1-15%:

Wherein, R ₈ and R ₉ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms, R ₈ , R _{Any CH 2 of the} groups shown in ₉ can be replaced by a cycloalkylene group having 3 to 5 carbon atoms; W represents O or S. The liquid crystal composition according to claim 1, further comprising a sixth component composed of one or more compounds represented by the general formula VI, and the mass percentage of the sixth component is 1-15%:

Wherein, R ₁₀ and R ₁₁ each independently represent an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms, R ₁₀ , R _{Any CH 2} in the groups shown in ₁₁ may be substituted with a cycloalkylene group having 3 to 5 carbon atoms. A liquid crystal display element of the liquid crystal composition according to any one of claims 1-7, wherein the liquid crystal display element is an active matrix display element or a passive matrix display element. The liquid crystal display element according to claim 8, wherein the active matrix display element is a TN-TFT, IPS-TFT or VA-TFT liquid crystal display element.