JPS5885825A - Colorless liquid crystal substance, liquid crystal composition and liquid crystal display element - Google Patents

Abstract

NEW MATERIAL:A compound of formulaI(R and R' are <=12C alkyl; X is CO2, OCO or direct bond). EXAMPLE:4-(gamma-Methoxypropylphenyl)-4'-pentylcyclohexylcarboxylate (formula II). USE:A liquid crystal compound, capable of extending the liquid crystal temperature range to the low temperature region, and giving liquid crystal display elements having improved response characteristics. PROCESS:Metallic sodium is dissolved in CH3OH, and gamma-bromopropylbenzene is dropped thereto under heating and refluxing to give gamma-methoxypropylbenzene. The resultant gamma-methoxypropylbenzene and anhydrous AlCl3 are then poured in methylene chloride, and acetyl chloride is dropped to the resultant reaction mixture under stirring and cooling with ice to afford 4-(gamma-methoxypropyl)- acetophenone, which is then reacted with formic acid, acetic anhydride, concentrated sulfuric acid and hydrogen peroxide to give the corresponding phenol. The resultant phenol is then reacted with trans-pentylcyclohexylcarboxylic acid chloride to afford the aimed compound of formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel colorless liquid crystal substance, a liquid crystal composition containing the colorless liquid crystal substance, and a liquid crystal display element having the liquid crystal composition as a liquid crystal layer.

In this specification, a colorless liquid crystal substance means a liquid crystal substance that does not absorb visible light. Further, the liquid crystalline substance includes a substance that exhibits a liquid crystal layer by itself at room temperature and is useful as a compounding component of a liquid crystal composition.

In order to obtain a liquid crystal display element with excellent response characteristics not only at room temperature but also in low-temperature environments, it is necessary to extend the liquid crystal temperature range to the low-temperature region. This becomes possible if the viscosity of the liquid crystal composition is reduced.

Typical conventional liquid crystal materials (integers) have high viscosity for the above purpose. On the other hand, the non-determined electrons of compounds with similar general formulas and oxygen move together, increasing the dielectric constant and resulting in high viscosity. On the other hand, the latter has a low dielectric constant, so its viscosity is low, but since it does not have polar atoms or groups like oxygen atoms, the polarity of the molecule as a whole is small, and therefore it cannot exhibit a liquid crystal phase. Therefore, we conducted further research and arrived at the present invention in the process of investigating a molecular structure that could provide properties intermediate between the two.

In addition, as described in JP-A-52-68881, - (where R is CH3, C, H,, n-C3HY, '', c,
H.

The compound represented by ) is a low-viscosity liquid crystal substance and can widen the liquid crystal temperature range. 1.However, this compound is a colored Schiff base liquid crystalline substance.

An object of the present invention is to provide a colorless liquid crystal material and a liquid crystal composition that can extend the liquid crystal temperature range to a low temperature region, and furthermore, it is an object of the present invention to provide a colorless liquid crystal material and a liquid crystal composition that can extend the liquid crystal temperature range to a low temperature region. The present invention provides a display element.

The colorless liquid crystalline substance of the present invention has the general formula (wherein R, R,' represent an alkyl group having a carbon number not exceeding 12, and Xl represents CO2, OCO, or a direct bond without anything). It is characterized by being a compound shown below. Among these, when X is a direct bond without any, and R and R' have 8 or less carbon atoms, the improvement in response characteristics due to lower viscosity is particularly excellent.

Incidentally, one of the physical property values of a liquid crystal material is refractive index anisotropy (hereinafter abbreviated as Δn. Δn is the difference between the extraordinary ray refractive index and the normal ray refractive index).

Δn greatly affects the display quality of a liquid crystal display element, and liquid crystals with a large Δn and liquid crystals with a small Δn are required depending on the driving method. It is well known that the display quality of a liquid crystal display element can be improved by using these.

In the present invention, it has been confirmed that Δn changes by changing the distance between the benzene ring and the oxygen atom. The colorless liquid crystal substance according to the present invention is also a compound that makes the Δn of the liquid crystal composition smaller.

In the above general formula, R and R' may have the same or different numbers of carbon atoms, and may be linear or branched. It is shown by this general formula. The compound is 1
It can be manufactured using conventional methods. In particular, the combination of Williamson's ether synthesis method, Friedel-Crafts reaction, and Earpilga method is the easiest.

Note 1. Not only Schiff base-based colored liquid crystal substances such as those in the conventional example, but also colored liquid crystal substances such as azo and azoxy-based substances are of course outside the scope of the present invention.

The liquid crystal composition of the present invention is characterized in that it contains a liquid crystal substance represented by the above general formula as a compounding component. Furthermore, since the liquid crystal material of the present invention can be mixed with any known type of liquid crystal material, the obtained liquid crystal composition can be applied to all liquid crystal display methods.

Furthermore, in the liquid crystal composition of the present invention, the colorless liquid crystal substance represented by the above general formula can be used in any composition ratio as desired, and it is also possible to consist only of the compound represented by the above general formula. .

Furthermore, the liquid crystal display element of the present invention is characterized by a structure in which the colorless liquid crystal composition of the present invention described above is sandwiched between two opposing electrode substrates as a liquid crystal layer, and a sleeping pressure is applied between the electrode substrates. This is an optical device that optically modulates the liquid crystal layer. The liquid crystal display element of the present invention is effective for various display systems such as TN type, phase transition type, and guest-host type.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the following explanation, the value of phase transition and position will vary slightly depending on the measurement method and purity. Further, the transition temperature from the crystal to the nematic phase is indicated by the symbol TCN, and the transition temperature from the nematic phase to the isotropic liquid phase is indicated by the symbol TNr. In addition, in the case of a monotropic transition that shows a liquid crystal phase only upon cooling, the transition temperature from an isotropic liquid phase to a nematic phase is 〉→CH, -? Manufacturing method and physical properties of colorless liquid crystal material expressed by MOR' 20 g of metallic sodium was dissolved in 600 g of anhydrous methanol, heated to reflux, and 120 g of r-7'o moprobilbenzene was added dropwise. . After 6 hours, the reaction solution was poured into 2 tons of ice water, and the separated oil gold benzene was extracted.

If benzene is distilled off and then distilled under reduced pressure, r-methoxypropylbenzene can be obtained. The boiling point of this compound is 96-98C
/15■Hg.

Next, add 1,5 methylene chloride and 195 g of anhydrous aluminum chloride and 100 g of r-methoxypropylbenzene.
and cooled on ice while stirring. 79 g of acetyl chloride was added dropwise little by little to this, and stirring was continued for 6 hours while cooling with water. After the generation of hydrogen chloride gas had stopped, the reaction solution was poured into dilute hydrochloric acid, and the methylene chloride layer was separated.
After methylene chloride is distilled off, 4-(r-methoxypropyl)-acetophenone is obtained by distillation under reduced pressure. The boiling point of this compound is 94-95 C/0.3 mHg.

4-(r-methoxypropyl)-acetophenone 679
and 88% formic acid (620 W) were mixed and stirred, and then acetic anhydride (310 m) and concentrated sulfuric acid (44.35%) hydrogen peroxide solution (1 ml) were mixed and stirred.
Drop in the order of 10 mA'. After heating to a temperature of 40 to -50 CK and stirring for 8 hours, one reaction solution was poured into water.

After extracting the separated oil and distilling off the melt, 100 mJ of methanol and 250 mJ of 2N caustic soda aqueous solution were added, and the mixture was heated under reflux for 2 hours. After cooling, the oil is separated by acidifying the first reaction solution with hydrochloric acid. Extract this with benzene,
After Hensen is distilled off, 4-(r-methoxyprobyltophenol is obtained) by distillation under reduced pressure. The boiling point of this compound is 106 to 108 C'/10 smHgf.

10 g of 4-(r-methoxypropyl)-7-ethanol was dissolved in 100111 benzene and 50% pyridine.
14 g of trans-pentylcyclohexylcarboxylic acid chloride is added dropwise while stirring, and stirring is continued at room temperature for 3 hours. The reaction solution is poured into water, extracted with benzene, and the residue after distilling off the benzene is recrystallized with acetone to obtain 4-(r-methoxypylphenyl)4/-pentylcyclohexylcarboxylate.

The infrared absorption spectrum of the compound obtained by this method is the first
As shown in the figure, the absorption of the ester bond is shown at 1750cPII''l, and the absorption of the ether bond is shown at 1120m-'.In addition, in the mass spectrum, the peak of the molecular ion is m
/e346. From both facts and the relationship with the raw material compounds, the chemotactic compound synthesized here is 4-(
It was confirmed that the product was methoxypropylphenyl 47-pentylcyclohexylcarboxylate (hereinafter abbreviated as MPCB).

The phase transition temperature of this compound is mp, =42'C.

(TIN) = 32tl'.

Similarly, compounds such as those exemplified below can be produced.

(1) 4-(r-methoxypropylphenyl)-4'-
Flohir cyclohexyl carboxylate (2) 4-(
γ-methoxypropylphenyl), a/-butylcyclohexylcarboxylate (3) 4- (r
(nimethoxypropylphenyl), i/-hexylne chlorohexyl carboxylate (4), 4- (r
-methoxypropylphenyl)-41-1-hebutylcyclohexylcarboxylate (5) 4-(r-methoxypropylphenyl)-47-octylcyclohexylcarboxylate (6) 4-(rI-ethoxypropylphenyl)-4 '-furobylcyclohexylcarpoxylate (7) 4-(r-ethoxypropylphenyl)
4/-pentylcyclohexylcarboxylate (8)
4-(r-ethoxypropylphenyl)-4'-hebutylcyclohexylcarboxylate (9) 4-(r
-proboxyglopylphenyl)-4'-7"ropylcyclohexylcarboxylate QOI 4-(r-7"roboxyglopylphenyl)
-4'-butylcyclohexylcarboxylate Ql)
4-(r-7'roboxypropylphenyl)-4-
Pentylcyclohexylcarboxylate Q5 4-(r, -7' oxypropylphenyl)=
4'-Hebutylcyclohexylcarboxylate, (13) 4-(r-butoxypropylphenyl)-4'
-Ethylcyclohexylcarboxylate Q4) 4
-(r-))xypropylphenyl)'4/-hentylcyclohexylcarboxylate (15) 4-(r-pentyloxyphenyl)-4'-ethylcyclohexylcarboxylate α94-(r-pentyloxyphenyl) 4 /-pentylcyclohexylcarboxylate Example 2 Characteristics of a liquid crystal composition containing the colorless liquid crystal material produced in Example 1 above as a compounding component> The liquid crystal composition of Example 1 described above was added to the liquid crystal composition having the composition shown in Table 1. MPCE manufactured in was added. Table 2 shows a comparison of the viscosity of the liquid crystal composition re-prepared in this way with the viscosity of the sample without the addition of the above sample (ie, only the base liquid crystal).

Table 1 Table 2 As is clear from Table 2, the liquid crystal compositions according to the present examples have a viscosity that is 15 to 35% lower than that of the corresponding parent liquid crystal.

Example 3 A response patent for a liquid crystal display element using the liquid crystal composition according to the present invention manufactured by rA in Example 2 above.
A TN-type liquid crystal display element was prepared using a liquid crystal composition containing 20% by weight of PCE as a liquid crystal composition.

This liquid crystal display element has transparent NESA electrodes formed inside each of the upper and lower glass substrates, and an alignment control film of an organic polymer compound for aligning liquid crystal molecules. The gap between the upper and lower substrates was controlled so that the thickness of the liquid crystal layer was approximately 10 μm. When a voltage of 6V was applied to this liquid crystal display element in an environment with an ambient temperature of -30C, the response time was 8 seconds.

In addition, in the liquid crystal display element using only the base liquid crystal B, the response time under the same conditions was 3.6 seconds.

That is, according to this embodiment, there is an effect that the response time of the liquid crystal display element can be greatly improved.

(Production method and properties of colorless liquid crystal substance expressed by CH2>sOR') 50'Occ of methylene chloride, 80 g of anhydrous aluminum chloride, and 130 g of trans-pentylcyclohexanecarboxylic acid chloride are placed in a Furusco and stirred.
106 g of (3-bromopropyl)benzene is added dropwise under water cooling. After 6 hours, the reaction solution was poured into a dilute aqueous hydrochloric acid solution to decompose the complex. If the methylene chloride layer is washed with water, dehydrated, and filtered, methylene chloride is removed, and recrystallized with ligroin, p-(
3'-bromopropyl)phenylketone is obtained. The melting point of this compound is 38-39C.

Next, add trans-4-pentylcyclohexyl-p-(3'-bromopropyl)phenylketone 409 to the flask.
Add 200Ω of methanol and stir. after that,
A sodium methylate-methanol solution prepared by dissolving 3.5 g of sodium metal in 80 g of anhydrous methanol was added dropwise and refluxed. 6- Concentrate the reaction solution, pour it into ice water, and extract the separated oil with benzene. After the benzene was distilled off, trans-4-pentylcyclohexyl-p-(3'-methoxypropyl)phenyl ketone was obtained by distillation under reduced pressure. The boiling point of this compound is 168-171C10,
It is 0'l■Hg.

Flasconidlan-4-pentylcyclohexyl-p
-(3'-Methoxypropyl)phenyl ketone 249 and 88% droplet acid 130 were mixed and stirred. Next, 65 μl of acetic anhydride, 1 μl of concentrated sulfuric acid, and 20 μl of 35% hydrogen peroxide were added dropwise in this order. After heating to 40-50C and stirring for 13 hours, one reaction solution was poured into water. The separated oil is extracted with benzene, the solvent is distilled off, distilled under reduced pressure, and recrystallized with methanol to obtain 4-(r-methoxypropyl), 4/
-Pentylcyclohexylcarbonyloxybenzene is also obtained. The boiling point of this compound is 181-188C10,
15 exposed Hg.

The infrared absorption spectrum of the compound obtained by this method is the second
As shown in the figure, absorption of ester bond is shown at 1720crIt''''1, and absorption of ether bond is shown at 1120cW1-'. Furthermore, a molecular ion peak appears at m/e 346 in the mass spectrum. From the relationship between both facts and the starting material compound i, the compound synthesized here is 4-(γ'methoxypropyl)4/-pentylcyclohexylcarbonyloxybenzene (hereinafter referred to as MPCC) represented by the following formula.
It is abbreviated as. ).

The phase transition temperature of this compound is mp,=30tr.

(Tra)=13t:'.

Similarly, compounds such as those exemplified below can be produced.

(1) 4-(γ-methoxypropyl)-4'-propylcyclohexylcarbonyloxybenzene (2) 4-(
γ-methoxypropyl)-47-butylcyclohexy to carbonyloxybenzene (3) 4-(γ-methoxypropyl)-4'- to xylcyclohexylcarbonyloxybenzene (4) 4-(γ-methoxypropyl)-
4'-heptylcyclohexylcarbonyloxybenzene (5) 4-(r-methoxypropyl)-4'-octylcyclohexylcarbonyloxybenzene (6)
j-(r-ethoxypropyl)-4'-probylcyclohexylcarbonyloxybenzene/(7) 4-(r-ethoxypropyl)-・4/-pebutylcyclohexylcarbonyloxybenzene (8) 4-(γ- ethoxypropyl)-4'-hebutylcyclohexylcarbonyloxybenzene (9) 4-(r-propoxypropyl)4
/-propylcyclohexylcarbonyloxybenzene α(It 4-(γ-propoxyprobyl) 4/
-butylcyclohexylcarbonyloxypenze/aυ
4-(γ-propoxypropyl)4/-pentylcyclohexylcarbonyloxybenzene (1347-(γ-propoxyp90vir)-4'-hephtercyclohexylcarbonyloxybenzene a 4-(r-butoxypropyl)-4' -Nitylcyclohexylcarbonyloxybenzene (J4) 4
-r-butoxyglovir)-4'-pentylcyclohexylcarbonyloxybenzene Q514-(γ-bentyloxyglovir) 4′
- Bentylcyclohexylcarbonyloxybenzene Example 5 Characteristics of a liquid crystal composition containing the colorless liquid crystal material produced in Example 4 above as a compounding component> A liquid crystal composition having the composition shown in Table 1 was added to the liquid crystal composition of Example 4 above Table 3 shows a comparison of the viscosity of the liquid crystal composition prepared in this manner with respect to the viscosity of the above sample without addition.
Shown below.

Table 3 As is clear from Table 3, the liquid crystal compositions according to the present examples have a viscosity that is 15 to 35% lower than that of the corresponding parent liquid crystal.

Example 6 Response characteristics of a liquid crystal display element using the liquid crystal composition according to the present invention prepared in Example 5> 20 weight of MPCC manufactured in Example 4 was added to the base liquid crystal B shown in Example-j2. A TN-type liquid crystal display element was prepared using the liquid crystal composition doped with % galvanic acid as a liquid crystal layer.

This liquid crystal display element has transparent NESA electrodes formed inside each of the upper and lower glass substrates, and an alignment control film of an organic polymer for aligning liquid crystal molecules. The gap between the upper and lower substrates was controlled so that the thickness of the liquid crystal layer was about 10 μm. When a voltage of 6 V was applied to this liquid crystal display element at an ambient temperature of -300°C, the response time was 1.8 seconds. In addition, in the liquid crystal display element using only the base liquid crystal B, the response time under the same conditions was 3.6 seconds.

In other words, according to this example as well, in the same manner as in Example 3,
The effect is that the response time of the liquid crystal display element can be greatly improved.

Example 7 Production method and physical properties of a colorless liquid crystal substance represented by General 2RR3)-gΣHeal+rOR' 4-n-pentyl-4/(acetylphenyl)cyclohexane 409, 20 g of thallium nitrate, and perchlorine Acid (7
Add 300 ml of methyl alcohol to 87 g (0%) and stir at room temperature for 4 hours. After that, it is filtered, and the filtrate is extracted with benzene, washed with water, and then dehydrated. After that, it was recrystallized from methyl alcohol to obtain the desired product, 4-n-pentyl-4.
'(Methoxycarbonylmethylphenyl) sifted to obtain hexane.

This compound has a melting point of 46-470.

Next, dry ethyl ether 4O-01RI was added to 6 g of lithium aluminum hydride and stirred. While cooling this with water, add 4-n-pentyl-4'(meth,oxycarbonylmethylphenyl)cyclohexane y36 (l) very slowly dropwise. After the completion of 11 drops, continue stirring at below 30C for 3 hours.Filter. The filtrate is extracted with benzene. After distilling off the benzene, recrystallization is performed with n-hexane.
-n-<7 f-4' (β-hydroxyethylphenyl)cyclohexane is obtained. The melting point of this compound is 44-46C.

20 g of this compound, 18 g of thionyl chloride and 0.0 g of pyridine.
Add 6g of benzene and 300ml of benzene and reflux for 5 hours. After distilling off excess thionyl chloride, t+4"-pentyl-4' (β-chloroethylphenyl)cyclohexane is obtained. The boiling point of this compound is 174-176 tl.
'/1■Hg.

17) 9 g of 4-n-pentyl-4' (β-chloroethylphenyl)cyclohexane, DMSolooml and 2.3 g of sodium cyanide are stirred at 140 to 150 C for 2 hours. After cooling, sodium cyachlorate aqueous solution (10%)
Add. Further, water is poured into this and the precipitate is recrystallized with ligroin to obtain 4-n-pentyl-4' (β-cyanoethylphenyl)cyclohexane. The melting point of this compound is 44-46C.

6 g of this compound, 11 g of caustic potassium, and 80 ml of water.
Add ethyl alcohol 130R1 and reflux for 10 hours. Ethyl alcohol is distilled off, extracted with ethyl ether, and then the extract is washed with water. After distilling off the ethyl ether, the residue was recrystallized from ligroin, resulting in 4-n-pentyl-
4/(β-carboxyethylphene)cyclohexane is obtained.

It was confirmed that this compound exhibits a liquid crystal phase in the range of 128.8 to 164.3r.

Next, 0.829 liters of lithium aluminum hydride was added to 5011 Il of dry ethyl ether and stirred. 4-
Squeeze 5 g of n-hentyl-4' (β-carboxyethylphenyl)cyclohexane. Thereafter, the mixture was stirred for 5 hours and filtered. Ethyl ether was distilled off from the filtrate and the residue was recrystallized from n-hexane to give 4-n-
A linker leading to pentyl-4' (r-methoxypropylphenyl)cyclo can be obtained. The melting point of this compound is 70.7
~72.5C.

3.6 g of thionyl chloride, 1 drop of pyridine, 59 d of benzene
Then, 4.3 g of 4n-pentyl-4'(r-methoxypropylphenyl)cyclohexane obtained above was added and refluxed for 5 hours. Thereafter, excess thionyl chloride is distilled off to obtain 4-n~benzene-4'(γ-chloropropylphenyl)cyclohexane. The melting point of this compound is 7
o, 7-72,5C.

Next, 1 g of metallic sodium was added to 50 ml of dry methyl alcohol and dissolved. To this is added 4.3 g of 4-n-pentyl-4'(r-chloropropylphenyl)cyclohexane obtained above. After 62 hours of reflux, the methyl alcohol was distilled off, and the residue was washed with water, dried, and distilled to give 4-n-henf-4'(r-methoxypropylphenyl)cyclohexane. .

The infrared absorption spectrum of this compound shows ether absorption at 1120 crn'''1 as shown in FIG.

From 2800 to 3000 crn-', absorption of -ci(, - group increases. Also, in the mass spectrum, a molecular ion peak appears at m/e302. From both facts, the compound synthesized here has the following formula: It was confirmed to be 4-n-be7f-4' (γ-methoxypropylphenyl).

The phase transition temperature of this compound is mp,=,zor,(TIN
) = -16C.

Similarly, the compounds shown below can be synthesized.

(1) 4-n-ethyl-4' (r-butoxypropy.
cyclohexane (2) 4-n-ethyl-4' (r-probyloxypropylphenyl) cyclohexane (314-n-propyl-4' (γ-methoxydipropylphenyl) cyclohexane (4) 4-n'-propyl -4' (r-ethoxypropylphenyl)cyclohexane (5) 4-n-propyl-4' (r-probyloxypropylphenyl)cyclohexane (6) 4-n-propyl-4' (γ-butoxypropylphenyl)cyclohexane (7) 4-n-butyl-4' (γ-methoxypropylphenyl)cyclohexane (8) 4-n-butyl-4'(γ-ethoxyglopylphenyl)cyclohexadi(914-n-butyl-4' ( γ-propylphenyl)cyclohexane Q (ll14-n-benzi/l/-4' (r-ethoxypropylphenyl)cyclohexane aυ 4- n-benzene4' (r-propylphenyl)cyclohexane α2) 4- n-hexyl-4' (γ-methoxypropylphenyl) cyclohexane 034 20-hexyl-4' (r-ethoxypropylphenyl) cyclohexane Ql) 4-1-hexyl-4' (r-probyloxypropylphenyl ) cyclohexane (J'; J 4-n-hebutyl-4' (γ-methoxypropylphenyl) cyclohexane (114-n-heptyl-4' (r-ethoxypropylphenyl) cyclohexane/ α14-n-hebutyl-4 '(T-probyloxypropylphenyl)cyclohexane a barrel 4-n-octyl-4' (r-ethoxypropylphenyl)cyclohexane (194-n-octyl-h-4', (r-ethoxypropylphel)/ Clohexane ■ 4-n-octyl-4'(r-probyloxypropylphenyl)cyclohexane Example 8 Characteristics of a liquid crystal composition containing the colorless liquid crystal substance produced in Example 7 above as a compounding component> Table 1 shows 5PCI produced in Example 7 above was added to the liquid crystal composition having the composition shown above.The properties of the liquid crystal composition thus re-prepared were compared to those of the sample without addition.

A comparison of the viscosities (ie, of the parent liquid crystal alone) is shown in Table 4.

Table 4 From Table 4, the viscosity of the liquid crystal composition according to this example is 36 to 41% lower, and Δn is 23 to 30% lower than that of the base liquid crystal.
It's getting smaller.

Example 9 - <Response characteristics of a liquid crystal display element prepared in the above Example 8 and using the liquid crystal composition according to the present invention> The 5P obtained in Example 7 was added to the base liquid crystal B used in Example 2.
A TN type liquid crystal display element was made using a liquid crystal composition containing 201n1% of CI. The element structure is the same as in Example 3. The gap between the glass substrates, that is, the thickness of the liquid crystal layer was adjusted to about 10 μm.

When a voltage of 6V was applied to this liquid crystal display element at -30C and the response time was measured, it was 1.4 seconds. Similarly, when only the base liquid crystal B was measured, the time was 3.6 seconds under the same conditions.

In other words, according to this example as well, in the same manner as in Example 3,
The effect is that the response time of the liquid crystal display element can be greatly improved.

As explained above, the colorless liquid crystal material of the present invention has a wide liquid crystal temperature range from room temperature to low temperature environments to high temperature environments.

Moreover, it is important to obtain a colorless liquid crystal composition with a small Δn. In addition, it has the effect of imparting excellent response characteristics to a liquid crystal display element using this colorless liquid crystal composition.

[Brief explanation of the drawing]

Figures 1 to 3 are a continuation of page 1 of various colorless liquids according to the present invention.0 Inventor: Inuyo Kotobuki, Kanto Kagaku Co., Ltd., 3-7 Nihonbashi Honmachi, Chuo-ku, Tokyo.0 Inventor: Kaoru Furuto, Tokyo. 3-7, Nihonbashi-honmachi, Chuo-ku, Kanto Kagaku Co., Ltd. Inventor: Hiroshi Hirai; Kanto Kagaku Co., Ltd., 3-7, Nihonbashi-honmachi, Chuo-ku, Tokyo; inventor: Yoshiaki Okabe, 3-1, Saiwaimachi, Hitachi City No. 1 Stock % formula 3-1-1 Saiwai-cho, Hitachi City Hitachi Research Institute, Hitachi, Ltd. 0 Inventor Shintabe Hattori 3-1-1 Saiwai-cho, Hitachi City Stock % formula 3 Saiwai-cho, Hitachi City Hitachi Research Institute, Hitachi, Ltd. 1-1-1 Hitachi, Ltd. 0 Inventor: Akio Mukai 3-1-1 Saiwai-cho, Hitachi City 3-1-1 Saiwai-cho, Hitachi City Hitachi Research Co., Ltd. Office @ Applicant Hitachi, Ltd. 5-1 Marunouchi-chome, Chiyoda-ku, Tokyo

Claims (1)

[Claims] 1. Represented by the general formula (in the formula, n and R/ represent an alkyl group with a carbon number not exceeding 12, and X represents CO, OCO, or a direct bond without any). A colorless liquid crystalline substance characterized by: 2. The colorless liquid crystalline substance according to claim 1, characterized in that the above general formula is represented by (wherein R,, R' represents an alkyl group having a carbon number not exceeding 8) . (In the formula, R and R' represent an alkyl group whose number of carbon atoms does not exceed 12, and X represents C40, OCO, or an empty direct bond.) A liquid crystal composition characterized by: 4. A liquid crystal layer is sandwiched between two opposing electrode substrates. In a liquid crystal display element in which the liquid crystal layer is optically modulated by applying a voltage between the electrode substrates, the liquid crystal layer (in the formula:
R' represents an alkyl group having a carbon number not exceeding 12;
represents a direct bond of Co2 or OCO or nothing. ) A liquid crystal display element characterized by containing a colorless liquid crystal substance represented by: