JPH0362752B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a liquid crystal composition, and in particular to an electro-optic system in which a liquid crystal composition containing a specific dye is interposed between two opposing electrode plates, and which utilizes the guest-host effect of the liquid crystal to enable good color display. The present invention relates to a liquid crystal composition used in an element. In general, display systems using liquid crystals include those that utilize the electro-optical effect of the liquid crystal substance itself, and those that utilize the electro-optical effect that occurs as a result of interaction with other contaminants. A typical example of the latter is
There is a display method using a liquid crystal composition in which a dye called a pleochroic dye is dissolved in a liquid crystal such as a nematic liquid crystal, a cholesteric liquid crystal, or a smectic liquid crystal. The present invention relates to a liquid crystal composition used in the latter method. Pigments called pleochroic pigments can be broadly divided into two types. In the first type, the direction of the absorption transition moment of visible light is almost parallel to the long axis direction of the molecule, and when the dye molecule is dissolved in the host liquid crystal as a guest molecule, the long axis of the dye molecule is aligned in the direction of the liquid crystal molecular axis. It is a pigment that has the property of aligning in the same direction as the Such dyes are called pleochroic dyes having parallel dichroism. In the second type, unlike the case of parallel dichroic dyes, the direction of the absorption transition moment of visible light is almost perpendicular to the long axis direction of the molecule, but when dissolved in liquid crystal as a guest molecule, the direction of the absorption transition moment of visible light is almost perpendicular to the long axis direction of the molecule. As in the case of chromatic dyes, it is a dye that has the property that the long axis of the dye molecules is aligned in the same direction as the alignment direction of the liquid crystal molecular axes. Such dyes are called pleochroic dyes having vertical dichroism. The present invention relates to the second of these, namely, a liquid crystal composition containing a pleochroic dye having vertical dichroism. A feature of pleochroic dyes having parallel dichroism or perpendicular dichroism is that the light absorption intensity is determined depending on the relative direction between the absorption transition moment of the dye molecule and the electric vector of light. In other words, the absorption intensity is highest when the direction of the absorption transition moment is parallel to the electric vector of the light.
The absorption intensity is the lowest when it is vertical. Therefore, in the case of a pleochroic dye having parallel dichroism, as shown in Figure 1, the dye molecules are oriented in the direction 3 relative to the light 2 polarized in the direction shown by arrow 1. The absorption intensity is large when the object is facing the direction 4 and 5, whereas the absorption intensity is small when the object is facing the directions 4 and 5. Conversely, in the case of pleochroic dyes with vertical dichroism, the absorption intensity is large when the dye molecules face the light in directions like 4 and 5 in Figure 1; The absorption intensity is small when facing the direction. Nematic liquid crystals containing such pleochroic pigments,
If a cholesteric liquid crystal or smectic liquid crystal is interposed between two opposing electrode plates and a voltage is applied, the liquid crystal molecules will cause disturbance motion or move in the direction of the electric field based on the dielectric properties and flow characteristics of the liquid crystal. It creates a uniform molecular arrangement. At this time, the pleochroic dye molecules also move together with the liquid crystal molecules, causing a change in the relative direction of the absorption transition moment of the pleochroic dye molecules and the incident light, resulting in a liquid crystal display device. This will result in a change in the light absorption properties of. Such a phenomenon is widely known as the "guest-host effect," and by utilizing this effect, an electrically controlled color display device can be constructed. (“Guest−Host
Interaction in Nematic Liquid Crystals：A
New Electro-Optic Effects”GH Heilmeier
and LAZanoni, Applied Physics Letters, Vol.
See volume 13, page 91 (1968). ) For example, including a polychromatic dye having parallel dichroism,
And a nematic liquid crystal with positive dielectric anisotropy,
The surface in contact with the liquid crystal is subjected to homogeneous alignment treatment,
When placed between two parallel transparent electrode plates, the liquid crystal molecules form a homogeneous alignment in which the long axes of the molecules are parallel to the electrode surfaces and aligned in a fixed direction (see FIG. 2). At this time, the pleochroic dye molecules 10 dissolved in the liquid crystal are also aligned in a constant direction with their long axes parallel to the electrode surface. White light 11, which travels in a direction perpendicular to the electrode surface and is polarized by the polarizing plate 13 in the same direction as the alignment direction of the liquid crystal, propagates through the guest-host material having such an arrangement state. Then, since the electric vector becomes parallel to the long axis of the pleochroic dye molecule, a specific wavelength region is particularly strongly absorbed by the pleochroic dye molecule, and as a result, the guest-host substance assumes a strongly colored state. Next, when an electric field is applied to the liquid crystal material having such an arrangement through the transparent electrode plate, since the dielectric anisotropy of the host liquid crystal is positive, the host liquid crystal molecules 9 and the guest pleochroic dye molecules It assumes a homeotropic orientation with its long axis aligned perpendicular to the electrode surface (see Figure 3). At this time, the long axis of the pleochroic dye molecule is perpendicular to the electric vector of the incident white polarized light 11, so the incident light is hardly absorbed by the pleochroic dye molecule, leaving the guest-host substance in a weakly colored state. appear. By utilizing the difference between such a strongly colored state and a weakly colored state, display by electrical drive becomes possible. The above example is a case where a parallel dichroic dye is used as the dye, but if a perpendicular dichroic dye is used, an effect completely opposite to the above example can be obtained. That is, when the guest-host material is oriented as shown in FIG. 2, it appears weakly colored, and when it is oriented as shown in FIG. 3, it appears strongly colored. In this way, by using a perpendicular dichroic dye, parallel dichroism can be achieved using exactly the same device configuration, liquid crystal alignment state, and host liquid crystal as in the case of a guest-host type liquid crystal display device using a conventional parallel dichroic dye. It becomes possible to display a display in which the shading is completely opposite to that in the case of sexual pigments. Furthermore, by using a vertical dichroic dye and a parallel dichroic dye, which have different hues as guests, color switching display becomes possible. That is, when the guest-host substance is oriented as shown in Figure 2, the color of the parallel dichroic dye changes, and when the guest-host substance is oriented as shown in Figure 3, the color of the parallel dichroic dye is The colors of each chromatic pigment will be observed. An example of color switching display using this effect is “Field-induced
color switching in Iiquid crystal displays”
M.Scnadt, Journal of Chemical Physics, No.
Seen in Volume 71, Page 2336 (published in 1980). The above was an example of using a nematic liquid crystal as the host liquid crystal, but even if a cholesteric liquid crystal or smectic liquid crystal is used as the host liquid crystal, if an appropriate element configuration and driving method are used, the same effect can be achieved as in the case of nematic liquid crystal and cholesteric liquid crystal. Display can be made by utilizing the difference between a strongly colored state and a weakly colored state. In order to obtain excellent display contrast in a liquid crystal display device that utilizes the guest-host effect as described above, the pleochroic dye that is the guest must exhibit strong coloring in one arrangement state and strong coloring in the other arrangement state. It must have the property of being nearly transparent and uncolored. In order to give a strongly colored state, the absorption transition moment of the pleochroic dye molecule needs to be aligned as much as possible parallel to the electric vector of the incident white light, i.e. as perpendicular as possible to the direction of light propagation, and on the other hand, close to transparent. In order to provide a non-colored state, the absorption transition moments of the pleochroic dye molecules need to be aligned as perpendicular to the electric vector of the incident white light as possible, ie, as parallel as possible to the direction of light propagation. The orderly arrangement of pleochroic dye molecules in a specific direction in a liquid crystal determines the contrast of the device. The orderliness of the arrangement of dye molecules in a liquid crystal medium is usually expressed by a value called an order parameter (degree of orientational order) or a value called a dichroic ratio. The order parameter (usually denoted by the symbol S) represents the degree of parallelism of the absorption transition moment of the dye molecule to the alignment direction of the liquid crystal molecules (usually denoted by a vector called director), and is defined as follows: Ru. S = 1/2 (3 ² -1) where the term cos ² θ is time averaged, and θ is the relationship between the absorption transition moment vector of the pleochroic dye and the orientation direction (director) of the liquid crystal. It's an angle. The order parameter S of the pleochroic dye dissolved in the liquid crystal can be determined using the following equation. S=A-A⊥/2A⊥+A In the formula, A and A⊥ represent the absorbance of the dye molecule with respect to light polarized parallel and perpendicular to the orientation direction (director) of the host liquid crystal, respectively.
In addition, the dichroic ratio (usually represented by the symbol R) is A
and A⊥, it can be determined by the following formula. R=A/A⊥ Therefore, by measuring the absorption spectrum, A,
By determining A⊥, the order parameter S and dichroic ratio R of the dye in the host liquid crystal can be obtained, and the orientation of the dye can be evaluated. The value of the order parameter S of the pleochroic dye dissolved in the host liquid crystal takes a value between 0 and 1 in the case of a pleochroic dye having parallel dichroism,
On the other hand, in the case of vertical dichroic dyes handled in the present invention, 0
takes a value between -0.5. Further, the value of the dichroic ratio R is 1 or more in the case of a parallel dichroic dye, and 1 or less in the case of a perpendicular dichroic dye. Pleochroic dyes generally have an elongated shape, and due to their molecular structure, their dichroism is generally parallel dichroism. Almost all of the merocyanine-based, azo-based, anthraquinone-based, and other pleochroic dyes that have been developed to date have parallel dichroism. An example of such a parallel dichroic dye is disclosed in Japanese Patent Application Laid-open No.
-56386 Publication, JP-A-52-2885, JP-A-Sho
This can be found in JP-A No. 53-126033, JP-A-54-71088, JP-A-55-123673, etc. On the other hand, vertical dichroic dyes are difficult to achieve both absorption transition moment direction and orientation due to their molecular structure, and have not been studied much at present. Vertical dichroic dyes with practical characteristics include tetrazine dyes, which are disclosed in JP-A-54-110185. (R′, R″ represent halogen atoms, alkyl groups, alkoxy groups, etc.) As a result of intensive study of the molecular structure of the anthraquinone pleochroic dye, which exhibits vertical dichroism in hues such as yellow, red, purple, and blue, the present invention is characterized by the following general formulas [] to [] A liquid crystal composition characterized by containing at least one type of anthraquinone dye represented by the formula and exhibiting vertical dichroism. [In the formula, R ³ and R ⁴ are an alkyl group, an alkenyl group, a phenethyl group which may be substituted with an alkoxy group, an alkoxycarbonyl group, or an alkylcarbonyloxy group.

[Formula] [However, R ⁵ is an alkyl group, an alkoxy group, a hydroxyl group,

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

【formula】

[Formula] (R″ represents an alkyl group), dialkylamino group, chlorine atom, nitro group,
represents a cyano group] or

[Formula] (wherein R ⁶ represents an alkyl group or an alkoxy group). ] [In the formula, R ³ and R ⁴ are alkyl groups,

[Formula] (However, R ⁵ represents an alkyl group or an alkoxy group)
or

[Formula] (wherein R ⁶ represents an alkyl group or an alkoxy group). ] [In the formula, R ³ and R ⁴ are

[Formula] (wherein R ⁵ represents an alkyl group or an alkoxy group). ] [In the formula, R ³ and R ⁴ represent an alkyl group, an alkenyl group, or a phenethyl group which may be substituted with an alkoxy group, an alkoxycarbonyl group, or an alkylcarbonyloxy group. ] [In the formula, R ⁷ is an alkyl group or an alkoxy group,
R ⁸ is an alkoxycarbonyl group or an alkyl group substituted with an alkylcarbonyloxy group, a phenethyl group substituted with an alkoxy group, an alkenyl group,

[expression] or

[Formula] (R ⁹ represents an alkyl group or an alkoxy group). ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group or an alkoxy group. ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group or an alkoxy group. ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group. ] Specific examples of R ³ and R ⁴ in the general formula [] include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a nonyl group. alkyl groups such as decyl, dodecyl, pentadecyl, octadecyl; alkoxy groups such as ethoxy, propoxy, butoxy; alkoxycarbonyl or acetoxy groups such as ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl; Alkyl group substituted with alkylcarbonyloxy group such as propionyloxy group; alkenyl group such as allyl group, propenyl group, butenyl group; phenethyl group; 4-position is methyl group, ethyl group,
Alkyl groups such as propyl group, butyl group, pentyl group, hexyl group, or methoxy group, ethoxy group,
propoxy group, butoxy group, pentyloxy group,
Examples include a cyclohexyl group which may be substituted with an alkoxy group such as a hexyloxy group; or a phenyl group having a substituent at the P position. This substituent includes an alkyl group, an alkoxy group, a 4-alkyl-substituted cyclohexyl group, a P-alkylphenyl group, a hydroxyl group, a 4-alkylcyclohexylcarbonyloxy group, a P-alkylbenzoylamino group, and a 4-alkylcyclohexylcarbonylamino group. , P-alkylphenylsulfonyloxy group, P-alkylphenylsulfonylamino group, P-alkylphenoxycarbonyl group, dialkylamino group, chlorine atom, nitro group or cyano group. Specific examples of the alkyl group as a substituent for the phenyl group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, and the like. Specific examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, peptyloxy group, octyloxy group, and the like. 4-
Specific examples of the alkyl-substituted cycloalkyl group include 4-propylcyclohexyl group and 4-pentylcyclohexyl group. Specific examples of P-alkylphenyl group include P-tolyl group, P-
Examples include butylphenyl group, P-pentylphenyl group, and the like. Specific examples of the 4-alkylcyclohexylcarbonyloxy group include 4-butylcyclohexylcarbonyloxy group and 4-pentylcyclohexylcarbonyloxy group. Specific examples of the P-alkylcyclohexylcarbonylamino group include 4-butylcyclohexylcarbonylamino group, 4-pentylcyclohexylcarbonylamino group, etc. Specific examples of the P-alkylbenzoylamino group include P-
Examples include toluoyl amino group and P-butylbenzoylamino group. Specific examples of the P-alkylphenylsulfonyloxy group include a tosyloxy group and a P-butylphenylsulfonyloxy group. Specific examples of P-alkylphenylsulfonylamino group include tosylamino group, P-
Examples include butylphenylsulfonylamino group. Specific examples of the P-alkylphenyloxycarbonyl group include a P-tolyloxycarbonyl group and a P-butylphenyloxycarbonyl group. Specific examples of the dialkylamino group include dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group, and the like. In R ³ and R ⁴ in the general formula [], specific examples of the alkyl group include methyl group, ethyl group, linear or branched propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group. group, nonyl group, decyl group, dodecyl group, pentadecyl group, octadecyl group, etc. Specific examples of the alkoxy group include ethoxy group, propoxy group, butoxy group, etc.

Specific examples of R ⁵ in [Formula] include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group; and methoxy group, ethoxy group, propoxy group, butoxy group. group, alkoxy groups such as pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group,

Specific examples of R ⁶ in [Formula] include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, or methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, Examples include alkoxy groups such as hexyloxy. In R ³ and R ⁴ in general formula []

Specific examples of R ⁵ in [Formula] include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group; and methoxy group, ethoxy group,
propoxy group, butoxy group, pentyloxy group,
Examples include alkoxy groups such as hexyloxy, heptyloxy, and octyloxy groups. Specific examples of R ³ and R ⁴ in the general formula [] include methyl group, ethyl group, linear or branched propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group. , decyl group, dodecyl group, pentadecyl group, octadecyl group, etc.; these include alkoxy groups such as ethoxy group, propoxy group, butoxy group; or an alkylcarbonyloxy group such as an acetoxy group or a propionyloxy group. Other examples include alkenyl groups such as allyl group, propenyl group, and butenyl group; and phenethyl group. In the general formula [], R ⁷ is a methyl group,
Ethyl group, propyl group, butyl group, pentyl group,
Examples include alkyl groups such as hexyl, heptyl and octyl groups, and alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy and octyloxy groups. R ⁸ is an ethoxycarbonylethyl group,
An alkyl group substituted with an alkoxycarbonyl group such as a butoxycarbonylethyl group; an alkyl group substituted with an alkoxycarbonyloxy group such as an acetoxyethyl group or a propionyloxyethyl group; a phenethyl group substituted with an alkoxy group; an allyl group or butenyl Alkenyl groups such as P-tolyl group, P-propylphenyl group, P-butylphenyl group, P-hexylphenyl group, P-methoxyphenyl group, P-propoxyphenyl group, P-
Pentyloxyphenyl group etc.

Group represented by the formula; tosylsulfonyl group, P-ethylphenylsulfonyl group, P-butylphenylsulfonyl group, P-methoxyphenylsulfonyl group,
P-butoxyphenylsulfonyl group etc.

Examples include groups represented by the formula: In the general formula [], specific examples of ^R10 include alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, and octyl group; and methoxy group, ethoxy group, and propoxy group. and alkoxy groups such as butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, and octyloxy group. Also

Specific examples of the group represented by [Formula] include P-tolyl group, P-propyl group, P-tolyl group, P-propyl group,
-propylphenyl group, P-butylphenyl group,
Examples include P-alkylphenyl groups such as P-hexylphenyl group, and P-alkoxyphenyl groups such as P-methoxyphenyl group, P-propoxyphenyl group, and P-pentyloxyphenyl group. In the general formula [], specific examples of R ¹⁰ and R ¹¹ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group,
Alkyl groups such as octyl group; and alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, and octyloxy group. In the general formula [], specific examples of R ¹⁰ and R ¹¹ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group,
Examples include alkyl groups such as octyl group. The nematic liquid crystal used in the present invention may be one that exhibits a nematic state within the operating temperature range.
You can choose from a fairly wide range. Furthermore, by adding an optically active substance to such a nematic liquid crystal, it can be made to assume a cholesteric state. Examples of nematic liquid crystals include the substances shown in Table 1 and their derivatives.

【table】

【table】

[Table] In the above table, R' represents an alkyl group or an alkoxy group, and X represents a nitro group, a cyano group, or a halogen atom. All of the liquid crystals listed in Table 1 have positive dielectric anisotropy. LCD also
It can be mixed with a liquid crystal having positive dielectric anisotropy to form a positive liquid crystal as a whole. Furthermore, it goes without saying that even a liquid crystal with negative dielectric anisotropy can be used as is if an appropriate element configuration and driving method are used. The host liquid crystal substance used in the present invention may be any of the liquid crystal compounds shown in Table 1 or a mixture thereof, but the following four types of liquid crystal compounds may be used. A liquid crystal substance sold by Merck under the trade name ZLI-1132 as a mixture of
types of liquid crystal compounds E from British Drug House as a mixture of
A liquid crystal material sold under the tradename -7 has been found to be particularly useful in the present invention. As the element used in the present invention, a known liquid crystal display element can be used. That is, generally, transparent electrodes in an arbitrary pattern are provided on two glass substrates, at least one of which is transparent, and the two glass substrates are placed parallel to each other with an appropriate spacer interposed so that the electrode surfaces face each other. A configuration of elements is used. In this case, the gap of the element is determined by the spacer. The element gap is 3 to 100μ.
m, particularly preferably from 5 to 50 μm from a practical standpoint. Examples of the vertical dichroic and pleochroic anthraquinone dyes used in the liquid crystal composition of the present invention and liquid crystal compositions using these dyes will be specifically described below with reference to Examples. Example 1 Examples of pleochroic anthraquinone dyes used in the present invention are shown in Tables 2 to 9 below, along with their hues.

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

【table】

[Table] The characteristics of each dye listed in Tables 2 to 9 were investigated as follows. That is, one of the dyes shown in Tables 2 to 9 is added as a pleochroic dye to the above-mentioned phenylcyclohexane mixed liquid crystal ZLI-1132, heated to 70°C or higher, and the liquid crystal becomes isotropic. The dye was dissolved by repeatedly stirring the liquid and then leaving it to cool. The above-mentioned liquid crystal composition prepared in this manner was applied to an intersubstrate gap 10 consisting of two glass substrates, upper and lower glass substrates, each having a transparent electrode and having a polyamide resin applied to the surface in contact with the liquid crystal, cured, and rubbed to give a homogeneous alignment treatment. It was encapsulated in an element of ~100 μm. In the element subjected to the alignment treatment, when no voltage is applied, the liquid crystal composition assumes a homogeneous alignment state as shown in FIG. 1, and the dye molecules also assume a similar alignment according to the host liquid crystal. Furthermore, the absorption spectrum of the guest-host element was measured using light polarized parallel to and perpendicular to the alignment direction of the liquid crystal molecules, and the absorbance of the dye for each polarized light was measured.
When I investigated ⊥, I found that for both dyes, A⊥ is better than A.
It was found that it was larger than the previous one and showed vertical dichroism. Furthermore, an accelerated deterioration test was conducted to obtain knowledge regarding the practical stability of the guest dye of this example. The liquid crystal containing the dye dissolved therein was sealed in the element and left in a sunshine weather meter for 100 hours, and the rate of decrease in absorbance was monitored.
As a result, the accelerated deterioration time for all of the dyes in this example was
It was found that the absorbance decrease rate was less than 10% after 100 hours, indicating excellent stability. The transparent glass substrate used in this example has a thickness of 300 nm (3×10 ^-4
The light transmittance was almost zero at wavelengths below (mm). Example 2 The aforementioned phenylcyclohexane-based mixed liquid crystal ZLI
−1132, the next dye (reddish yellow) A liquid crystal composition saturated with
100 μm). In such a device, the liquid crystal composition assumes a homogeneous orientation as shown in FIG. Using light polarized parallel to and perpendicular to the alignment direction of liquid crystal molecules,
The absorption spectrum of the guest-host element was measured to determine the absorbance A and A⊥ of the dye for each of the polarized lights and the maximum absorption wavelength. In determining the absorbance of the dye, corrections were made for absorption by the host liquid crystal and reflection loss of the element. Using the absorbance value A of the dye for each polarized light and the value of A⊥ obtained in this way, the value of the order parameter S is calculated from the above formula S=A−A⊥/2A⊥+A, and the value of the order parameter S is calculated using the formula R The dichroic ratio R values were calculated from =A-A⊥. The absorption spectrum of the dye of this example obtained as described above is shown in FIG. In the figure, curve 15 is A
Curve 16 shows A⊥, respectively. Absorption peaks are seen at 471 nm and 494 nm, of which the maximum absorption wavelength is 494 nm. A at the maximum absorption wavelength was 0.794, and A⊥ was 1.294. Therefore, the order parameter S of the dye of this example is -
0.15, and the dichroic ratio R is 0.61. Example 3 The following dye (reddish yellow) was added as a pleochroic dye to the same liquid crystal as that used in Example 2. A liquid crystal composition containing 0.30% by weight of
100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 17 indicates A, and a curve 18 indicates A⊥. Absorption peaks are 472nm and 493n
The maximum absorption wavelength is 493 nm. A at the maximum absorption wavelength is 0.439, A⊥
was 0.898. Therefore, the order parameter S of the dye of this example is -0.21, and the dichroic ratio R is 0.49. Example 4 A liquid crystal completely similar to that used in Example 2 was coated with the following dye (reddish yellow). The liquid crystal composition saturated with the liquid crystal composition was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was about 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 19 indicates A, and a curve 20 indicates A⊥.
Absorption peaks are seen at 464 nm and 496 nm, of which the maximum absorption wavelength is 496 nm. A at the maximum absorption wavelength was 0.067, and A⊥ was 0.116. Therefore, the order parameter S of the dye of this example is -0.16, and the dichroic ratio R is 0.58. Example 5 A liquid crystal completely similar to that used in Example 2 was coated with the following dye (blueish red). The liquid crystal composition saturated with the liquid crystal composition was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was about 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 21 indicates A, and a curve 22 indicates A⊥.
Absorption peaks are seen at 543 nm and 584 nm, of which the maximum absorption wavelength is 543 nm. A at the maximum absorption wavelength was 0.056, and A⊥ was 0.214. Therefore, the order parameter S of the dye of this example is -0.33, and the dichroic ratio R is 0.26. Example 6 The following dye (red) was added to the same liquid crystal as that used in Example 2. A liquid crystal composition to which 0.19% by weight of was added was encapsulated in the same device as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, curve 23 represents A, and curve 24 represents A⊥
are shown respectively. Absorption peaks are 490nm and 508nm
and 544 nm, of which the maximum absorption wavelength is 508 nm. A at the maximum absorption wavelength is
0.113, and A⊥ was 0.451. Therefore, the order parameter S of the dye of this example is -0.33, and the dichroic ratio R is 0.25. Example 7 The following dye (yellowish red) was added to the same liquid crystal as that used in Example 2. A liquid crystal composition containing 0.29% by weight of
100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 25 indicates A, and a curve 26 indicates A⊥. Absorption peaks are seen at 472nm, 499nm and 533nm, of which the maximum absorption wavelength is
It is 499nm. A at the maximum absorption wavelength is
0.169, and A⊥ was 0.646. Therefore, the order parameter of the dye of this example is -0.33, and the dichroic ratio R is 0.26. Example 8 A liquid crystal completely similar to that used in Example 2 was coated with the following dye (yellowish red). A liquid crystal composition to which 0.25% by weight of was added was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, curve 27 indicates A, and curve 28 indicates A.
⊥ is shown respectively. Absorption peaks are 471nm and 495n
m and 528 nm, of which the maximum absorption wavelength is 495 nm. A at maximum absorption wavelength
was 0.244, and A⊥ was 1.046. Therefore, the order parameter S of the dye of this example is -0.34, and the dichroic ratio R is 0.24. Example 9 The following dye (yellow) was added to the same liquid crystal as that used in Example 2. The liquid crystal composition saturated with the liquid crystal composition was encapsulated in the same device as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 29 indicates A, and a curve 30 indicates A⊥. The maximum absorption wavelength was 450 nm. A at the maximum absorption wavelength was 0.195, and A⊥ was 0.275. Therefore, the order parameter S of the dye of this example is -0.11, and the dichroic ratio R is 0.71. Example 10 The same liquid crystal as that used in Example 2 was coated with the following dye (yellow). The liquid crystal composition saturated with the liquid crystal composition was encapsulated in the same device as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, a curve 31 indicates A, and a curve 32 indicates A⊥. The maximum absorption wavelength was 460 nm. A at the maximum absorption wavelength was 0.040, and A⊥ was 0.046. Therefore, the order parameter S of the dye of this example is -0.05, and the dichroic ratio R is 0.87. Example 11 A liquid crystal completely similar to that used in Example 2 was coated with the following dye (reddish yellow). A liquid crystal composition containing 0.43% by weight of the liquid crystal composition was encapsulated in the same device as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is the 13th
As shown in the figure. In the figure, a curve 33 indicates A, and a curve 34 indicates A⊥. The maximum absorption wavelength is 482 nm. A at the maximum absorption wavelength is 0.258, A⊥
was 0.396. Therefore, the order parameter S of the dye of this example is -0.13, and the dichroic ratio R is 0.65. Example 12 The following dye (purple) was added to the same liquid crystal as that used in Example 2. A liquid crystal composition containing 0.56% by weight of 0.56% by weight was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was approximately 10 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, curve 37 indicates A, and curve 38 indicates A.
⊥ is shown respectively. The absorption peak is at 546nm and
It is observed at 584nm, of which the maximum absorption wavelength is 546n.
It is m. A at the maximum absorption wavelength is 0.072,
A⊥ was 0.122. Therefore, the order parameter S of the dye of this example is -0.16, and the dichroic ratio R is
It becomes 0.59. Example 13 The following dye (blue) was added to the same liquid crystal as that used in Example 2. A liquid crystal composition containing 0.35% by weight of 0.35% by weight was encapsulated in the same device as in Example 2 (however, the gap between the substrates was approximately 50 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, curve 39 indicates A, and curve 40 indicates A.
⊥ is shown respectively. The maximum absorption wavelength was 592 nm. A at the maximum absorption wavelength is 0.295, A⊥
was 0.358. Therefore, the order parameter S is -0.06 and the dichroic ratio R is 0.82. Example 14 A liquid crystal exactly the same as that used in Example 2 was coated with the following dye (greenish blue). The liquid crystal composition saturated with was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure,
Curve 41 represents A, and curve 42 represents A⊥. Absorption peaks are seen at 600nm and 642nm,
The maximum absorption wavelength was 642 nm. A at the maximum absorption wavelength was 0.360, and A⊥ was 0.418. Therefore, the order parameter S of the dye of this example is -0.05, and the dichroic ratio R is 0.86. Example 15 A liquid crystal completely similar to that used in Example 2 was coated with the following dye (blueish red). The liquid crystal composition saturated with was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was approximately 100 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure,
Curve 43 represents A, and curve 44 represents A⊥. Absorption peaks are at 518nm, 555nm and 590nm
The maximum absorption wavelength was 555 nm. A at the maximum absorption wavelength is 0.193, A⊥
was 0.361. Therefore, the order parameter S of the dye of this example is -0.18, and the dichroic ratio R is 0.53. Example 16 A liquid crystal exactly similar to that used in Example 2 was treated with the following dye (purple). A liquid crystal composition containing 0.30% by weight of 0.3% by weight was encapsulated in a device exactly the same as in Example 2 (however, the gap between the substrates was approximately 50 μm), and the absorption spectrum was measured in the same manner as in Example 2. The spectrum is shown in FIG. In the figure, curve 45 indicates A, and curve 46 indicates A.
⊥ is shown respectively. The absorption peak is 505nm,
It was observed at 544 nm and 580 nm, of which the maximum absorption wavelength was 544 nm. A at the maximum absorption wavelength was 0.236, and A⊥ was 0.386. Therefore, the order parameter S of the dye of this example is -
0.15, and the dichroic ratio R is 0.61.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the relative directional relationship between a pleochroic dye and light, FIG. 2 is a schematic cross-sectional view of an example device of the present invention in a state where no voltage is applied, and FIG. 4 to 18 are graphs showing the spectral characteristics of the display elements of Examples 2 to 16 of the present invention. 6... Observer, 7... Transparent glass substrate, 8...
Transparent electrode, 9...liquid crystal molecule, 10...polychroic dye molecule, 11...incident white light, 13...polarizing plate.

Claims (1)

[Scope of Claims] 1. A liquid crystal composition characterized by containing a liquid crystal compound and at least one type of anthraquinone dye represented by the following general formulas [] to [] that exhibits vertical dichroism. . [In the formula, R ³ and R ⁴ are an alkoxy group, an alkyl group which may be substituted with an alkoxycarbonyl group or an alkylcarbonyloxy group, an alkenyl group, a phenethyl group, [Formula] [However, R ⁵ is an alkyl group , alkoxy group, hydroxyl group, [formula] [formula] [formula] [formula] [formula] [formula] [formula] [formula] (R″ represents an alkyl group), dialkylamino group, chlorine atom, nitro group ,
represents a cyano group] or [Formula] (wherein R ⁶ represents an alkyl group or an alkoxy group). ] [In the formula, R ³ and R ⁴ are an alkyl group, [Formula] (However, R ⁵ is an alkyl group or an alkoxy group)
or [Formula] (wherein R ⁶ represents an alkyl group or an alkoxy group). ] [Wherein, R ³ and R ⁴ represent [Formula] (wherein R ⁵ represents an alkyl group or an alkoxy group). ] [In the formula, R ³ and R ⁴ represent an alkyl group, an alkenyl group, or a phenethyl group that may be substituted with an alkoxy group, an alkoxycarbonyl group, or an alkylcarbonyloxy group. ] [In the formula, R ⁷ is an alkyl group or an alkoxy group,
R ⁸ is an alkoxycarbonyl group or an alkyl group substituted with an alkylcarbonyloxy group, a phenethyl group substituted with an alkoxy group, an alkenyl group, [Formula] or [Formula] (R ⁹ represents an alkyl group or an alkoxy group) represents. ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group or an alkoxy group. ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group or an alkoxy group. ] [In the formula, R ¹⁰ and R ¹¹ represent an alkyl group. ]