JPH06174919A - Rotary polarization film and liquid crystal display constituted by using the same - Google Patents

Abstract

PURPOSE:To improve the contrast and coloration of a liquid crystal display by incorporating a compd. which has specific transition and in which plural chromphores exist in asymmetric positions and asymmetric exciton interaction is induced among the chromphores as an optically active substance into this film. CONSTITUTION:This rotary polarization film contains the compd. which has the pi-pi transition and in which the plural chromphores exist ion the asymmetric positions and the asymmetric exciton interaction is induced among the chromphores as the optically active substance. This optically active substance is more preferably used by being incorporated at 0.1 to 30% into the stretched film of a polymer having a positive or negative intrinsic double refractive value as not only the rotary polarization but its double refraction can be independently controlled. The lower content thereof is more preferable in terms of absorption, bleed out and cost. Then, the larger G value of this optically active substance, i.e., the ratio of the specific angle of rotation and absorption intensity thereof is more preferable. More specifically, the specific angle of rotation is preferably >=100 deg. and the G value is >=1/3000. This liquid crystal display device is constituted by disposing the above-mentioned rotary polarization film as a compensation film into a liquid crystal cell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using twisted nematic liquid crystal, cholesteric liquid crystal, smectic liquid crystal or the like, and a rotatory film used for improving display quality such as color removal of the liquid crystal display device and increase of contrast. And a liquid crystal display device using the same.

[0002]

2. Description of the Related Art A liquid crystal display device can be directly connected to an IC circuit with low voltage and low power consumption, has a variety of display functions, can be manufactured with high productivity, and can be reduced in weight. It has features and its applications have expanded. Currently, a dot-matrix liquid crystal display device used in OA-related equipment such as a word processor and a personal computer, a super twisted nematic liquid crystal display device (hereinafter STN-LCD) having a twist angle of liquid crystal molecules of 160 ° or more has been put into practical use and has become the mainstream. ing. This is because the STN-LCD can maintain high contrast even during high-multiplex driving, as compared with the conventional twisted nematic liquid crystal display device (TN-LCD) having a twist angle of 90 °.

However, in the STN-LCD,
It was difficult to make the background color of the display screen white, and the background usually had a green to yellow-red tint, and the display quality was insufficient. In order to solve this background coloring problem, a method of disposing one or more birefringent films between a pair of polarizing plates has been proposed.

For example, in JP-A-63-189804, the retardation value (product of birefringence value and film thickness) is 2
A method of using a birefringent polycarbonate film uniaxially stretched to have a thickness of 00 to 350 nm or 475 to 625 nm is disclosed. In addition, JP-A-63-16
No. 7303 discloses a cellulose-based birefringent film, and JP-A-2-42406 discloses a thermoplastic birefringent polymer film.

Further, Japanese Patent Laid-Open No. 63-167304 discloses that
A film laminate in which two or more uniaxially stretched birefringent films or sheets are stacked is disclosed. All of these inventions compensate the phase difference caused by passing through the liquid crystal by controlling the birefringence, but the compensation effect is not sufficient, and complete color removal has not yet been achieved. . On the other hand, a method of compensating using a film having optical activity has been devised, for example, JP-A-2-96115 and JP-A-3-352.
No. 01 discloses a method using a film in which obliquely vapor-deposited layers which are deviated from each other by a certain angle are laminated, and also disclosed in JP-A-2-245725.
JP-A No. 1994-242 discloses a method of using a film obtained by laminating a water-spreading polymer film. In addition, JP-A-63-149624
JP-A-63-271433, JP-A 1-20663
18, JP-A-2-222220, JP-A-62-13.
6602, JP-A-3-294821 and the like disclose methods using a liquid crystalline polymer film.

In the above invention, the problem of coloring when viewed from the front is considerably improved by using a film having optical rotatory power. However, this type of film is complicated in the manufacturing method and costly, and the optical rotation is high. And its wavelength dependence (optical rotation dispersion)
It was not possible to completely compensate the background coloring because it was difficult to control.

The present inventors independently control optical rotatory power and birefringence by a compensation film characterized by comprising a non-liquid crystal forming polymer having no optical rotatory power and an optical rotatory substance, Allowed significant color removal and has already filed. (Japanese Patent Application No. 4-179962) However, when it is necessary to impart a large optical rotatory power, it is necessary to add a large amount of the optical rotatory substance, and there are problems of bleed-out and cost.

[0008]

SUMMARY OF THE INVENTION The first object of the present invention is to:
Another object of the present invention is to provide a compensating film capable of improving the background coloring and viewing angle characteristics of a liquid crystal display, that is, the reduction in contrast and the change in color due to the viewing angle. The second object of the present invention is
In, using the compensation film having the above excellent characteristics,
An object is to provide a liquid crystal display device having excellent display quality.

[0009]

The above object of the present invention has been achieved by the following means. That is, (1) a plurality of chromophores having a π-π ^* transition are present at asymmetric positions, and a compound that causes an asymmetric exciton interaction between the chromophores is included as an optically active substance. Polarizing film. (2) An optical rotatory film comprising the optical rotatory substance described in (1) above and a polymer having no optical rotatory power. (3) The optical rotatory film as described in (2) above, wherein the polymer has positive intrinsic birefringence and also has optical transparency. (4) The optical rotatory film as described in (2) above, wherein the polymer has negative intrinsic birefringence and also has optical transparency. (5) A liquid crystal display device, characterized in that at least the optical rotation film according to (1), (2), (3) or (4) is disposed on at least one side of a liquid crystal cell as a compensation film. (6) The liquid crystal display device according to the above (5), wherein the liquid crystal display device has a backlight, and the optical rotatory film does not substantially absorb at the wavelength of the bright line of the light of the backlight.

The present invention will be described in detail below. First, the optical rotatory substance used in the present invention will be described. Regarding optically active compounds and optical rotatory power, the "coupled oscillator theory" and "group polarizability theory" by Kuhn and Kirkwood have long been known. (Kuhn, W., Trans. Faraday So
c., 26, 293 (1930), Kirkwood, JG, J. Che.
m. Phys., 5, 479 (1937)) which later evolved into the exciton theory in optical rotation. (Koji Nakanishi, Nobuyuki Harada, "Circular dichroism spectrum", Tokyo Kagaku Dojin (198
2)) The present inventors have remarkably improved the background coloring and contrast of an LCD by an optical rotation film characterized by containing a compound exhibiting strong optical rotation and optical dispersion by asymmetric exciton interaction. As a result, they have found the present invention.

The optical rotatory dispersion of the optical rotatory substance is given by the Cotton effect, and it is more preferable that the chromophore is closer to the asymmetric center.
Further, it has a close relationship with the absorption maximum wavelength (λ max) and the absorption intensity (ε) due to the chromophore, but when used in a liquid crystal display, the transmitted light must not be colored. Usually, a liquid crystal display of a liquid crystal display device has a backlight, and its light is R (630 nm), G (550 nm), B.
It has a bright line of (440 nm). It is preferred that there is substantially no absorption at said wavelength. Specifically, the transmittance at each wavelength is preferably 70% to 100%, and more preferably 90% or more. Further, it is preferable that the difference in transmittance at each wavelength is within 10%. Generally, the optical rotatory dispersion near λmax of absorption is large,
Further, the larger ε, the larger the optical rotatory dispersion. Therefore, λmax is different from the wavelengths of R, G, and B, and a chromophore having sharp absorption is preferable.

The optical rotatory substance of the present invention contains 0.1 to 0.1 in a stretched film of a polymer having a positive or negative intrinsic birefringence value.
By containing 30%, not only the optical rotatory power but also the birefringence can be controlled independently, which is more preferable, but the smaller the content, the more preferable in terms of absorption, bleed-out and cost. Therefore, the larger the G value of the optical rotatory substance, that is, the ratio between the specific optical rotation and ε, the better. Specifically, the specific rotation is 10
It is preferably 0 ° or more, and the G value is preferably 1/3000 or more.

The optical rotatory film of the present invention is greatly characterized in that the required optical rotatory dispersion and optical rotatory power can be freely expressed in accordance with the characteristics of the liquid crystal. That is, R,
In order to control the optical rotation at each wavelength of G and B, it is possible to achieve the required optical rotation at each wavelength by selecting an optically active substance and controlling the added amount and the film thickness. Further, if necessary, two or more kinds of optical rotatory substances may be combined. Specific examples of the optically active substance of the present invention are shown below, but the present invention is not limited thereto. In the formula, Me represents a methyl group and Et represents an ethyl group.

[0014]

[Chemical 1]

[0015]

[Chemical 2]

[0016]

[Chemical 3]

[0017]

[Chemical 4]

[0018]

[Chemical 5]

[0019]

[Chemical 6]

[0020]

[Chemical 7]

[0021]

[Chemical 8]

[0022]

[Chemical 9]

[0023]

[Chemical 10]

[0024]

[Chemical 11]

[0025]

[Chemical 12]

[0026]

[Chemical 13]

[0027]

[Chemical 14]

In the optical rotatory film of the present invention, birefringence can be imparted independently of optical rotatory property by including the rotatory substance in at least a polymer having no optical rotatory property,
More preferable. Next, the polymer having at least a positive or negative intrinsic birefringence value having no optical rotatory power of the present invention will be described in detail.

As a polymer having a positive intrinsic birefringence,
Although not particularly limited, the film preferably has a light transmittance of 70% or more and is achromatic, and more preferably has a light transmittance of 90% or more and is achromatic. Further, if the polymer has a liquid crystal forming ability such as nematic, it becomes unfavorable because it becomes a cholesteric liquid crystal by the addition of an optical rotatory substance and exhibits optical rotatory power and cannot be controlled independently. Specifically, polycarbonate, polyarylate, polyethylene terephthalate, polysulfone, polyether sulfone, polyphenylene sulfide, polyphenylene oxide, polyallyl sulfone, polyamide imide, polyimide, polyolefin, polyvinyl chloride, cellulose, polyethylene naphthalate, other polyester-based high Molecules and the like are preferable, and particularly, polymers such as polycarbonate-based polymers, polyarylate-based polymers, polysulfone-based polymers, polyester-based polymers and the like, which have a large intrinsic birefringence value and are easy to form a planar homogeneous film by solution casting preferable. The above-mentioned polymer is not only a homopolymer but also a copolymer,
They may be derivatives or blends thereof.

Also in the polymer having a negative intrinsic birefringence value used in the compensation film of the present invention, it is preferable that the film has a light transmittance of 70% or more and is achromatic, and more preferably a light transmittance of 90. % Or more is achromatic. Specifically, styrene-based polymers, acrylic acid ester-based polymers, methacrylic acid ester-based polymers, acrylonitrile-based polymers and methacrylonitrile-based polymers, vinylnaphthalene-based polymers, vinylpyridine-based polymers, vinylcarbazole-based polymers. Polymers and phenylacrylamide-based polymers are preferable, and styrene-based polymers are from three points of view, that is, the absolute value of the intrinsic birefringence value is large, the transparency is excellent, there is no coloring, and solution film formation is possible. Most preferred.

Here, the styrene-based polymer is a homopolymer of styrene and a styrene derivative, a copolymer of styrene and a styrene derivative, a blended product or the like. The styrene derivative is, for example, α-methylstyrene, o-methylstyrene, p-methylstyrene, p-chlorostyrene, o.
Examples include, but are not limited to, -nitrostyrene, p-aminostyrene, p-carboxystyrene, p-phenylstyrene, and 2,5-dichlorostyrene. Copolymers and blends of styrene and styrene derivatives (hereinafter abbreviated as ST) are not particularly limited as long as they have an appropriate film-forming property with ST, and even if they have a phase separation structure, transparency, etc. Is not impaired and is a subject of the present invention.
T / acrylonitrile, ST / methacrylonitrile,
ST / methyl methacrylate, ST / ethyl methacrylate, ST / α-chloroacrylonitrile, ST-methyl acrylate, ST / ethyl acrylate, ST / butyl acrylate, ST / acrylic acid, ST / methacrylic acid, ST / butadiene, ST / isoprene, ST / maleic anhydride, ST / N-phenylmaleimide, ST / itaconic acid, ST / vinylcarbazole, ST / n-phenylacrylamide, ST / vinylpyridine, ST / vinylnaphthalene, α- Methylstyrene / acrylonitrile, α-methylstyrene / methacrylonitrile, ST /
Examples thereof include vinyl acetate copolymers and styrene / styrene derivative copolymers. Of course, in addition to the binary copolymers listed above, ternary or higher copolymers such as ST / α-methylstyrene / acrylonitrile, ST / N-phenylmaleimide / acrylonitrile, and ST / α-methylstyrene / methylmethacrylate can also be used.

Further, a graft copolymer obtained by addition-polymerizing the styrene-based polymer to rubber such as SBR, SBS and BR can also be used. In addition to the above-mentioned styrene homopolymer, styrene derivative homopolymer, and blend of styrene and styrene derivative copolymer, the blend includes a polymer composed of styrene and a styrene derivative (hereinafter abbreviated as PST) and a polymer not containing PST. Blends of can also be used. Examples of these blends include PST / butyl cellulose and PST / chroman resin. The styrene-based polymer is generally fragile and has a problem in brittleness. As the polymer having a negative intrinsic birefringence value of the present invention, the styrene-based polymer is addition-polymerized with a rubber such as SBR, SBS or BR. The above graft copolymer is preferred.

Next, a method for producing the optical rotatory film of the present invention will be described. When the polymer having no optical rotatory power and the optical rotatory substance have a common solvent or they are compatible with each other, a dope containing them is used to perform either casting in a molten state or solution casting. The optical rotatory film of the present invention can also be produced by a method. From the viewpoint of the stability of the optical rotatory substance and the smoothness of the surface of the film, solution casting is preferable. In the case of solution casting, the solvent is preferably a common solvent for the polymer and the optical rotatory substance, and the optical rotatory substance may be added in the state of dope, or may be added to the pipe immediately before casting.

The polymer having at least no optical activity used in the present invention is mostly insoluble in water and soluble in an organic solvent. Therefore, as the common solvent for the polymer and the optically active substance, organic solvents such as methylene chloride, dioxane, ethyl acetate, tetrahydrofuran, acetone, methyl ethyl ketone, toluene, cyclohexanone, benzyl alcohol, methyl cellosolve, butyl acetate are preferable. The dope is cast on a stainless steel band or stainless steel drum, peeled off, dried while carrying out roll conveyance,
The optical rotatory film of the present invention can be obtained by winding the material into a roll after performing an orientation operation such as stretching. The film thickness is 1
0 to 200 μ is preferable and the amount of the optically active substance is 0.1 to 30.
% Is preferred.

When there is no common solvent for the polymer and the optical rotatory substance, the optical rotatory substance may be coated on the polymer film before or after the orientation operation such as stretching. At this time, it is preferable to use a transparent polymer that is compatible with the optical rotatory substance and has good adhesion with the polymer as a binder. When the optical rotatory substance is soluble in water, the coating liquid contains gelatin, methylcellulose, alginic acid, pectin, gum arabic, pullulan, etc. as a water-soluble synthetic binder such as polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyvinyl. It is preferable to use a solution in which an optical rotatory substance is dissolved in an aqueous solution of sodium benzenesulfonate and polyethylene glycol. When the optically active substance is insoluble in water, it is preferable to use a solid dispersion of the optically active substance in the polymer aqueous solution as a coating liquid. Further, in the case of an organic solvent in which the optical rotatory substance is soluble but the polymer used in the present invention is insoluble, the optical rotatory substance may be dissolved in the organic solvent and applied as a coating solution in the same manner as above.

Next, a liquid crystal display device of the present invention and a display device equipped with the same will be described. The liquid crystal display device is a liquid crystal device handbunker (Japan Society for the Promotion of Science
42 Committee), or as described in Figure 1,
At least a backside white light source (backlight) (BL), a polarizer (P1), a compensation film (D1), a liquid crystal cell (L)
C), a compensation film (D2), and an analyzer (P2). At this time, only one compensation film is D1.
Or, it is attached to D2, two pieces are attached separately to D1 and D2, or two pieces are attached to D1 or D2 in a stacked manner. 3
There is a method such as mounting one or more retardation films in combination with D1 and D2. In the embodiment of the present invention, a method of mounting two compensation films on D1 and D2 is preferable because the viewing angle becomes wide. This aspect will be described.

In the present invention, one optical rotation film may be used, but it is preferable to use two optical rotation films. As shown in FIG. 1, at least one of D1 and D2 has an optical rotatory film containing a polymer having no optical rotatory power and an optical rotatory substance as shown in FIG. When a plurality of optical rotatory films of the present invention are used, the positions thereof may be anywhere and the optical rotatory substances used for each may be the same or different. When a compensation film made of a polymer having a positive intrinsic birefringence and a compensation film made of a polymer having a negative intrinsic birefringence are used in combination, at least one of them is an optical rotatory film of the present invention, and both of them A film may be used. When laminating both films on one side of a liquid crystal cell, overlapping the stretching axes of the films undesirably cancels the retardation and the crossing angle is 70 ° to 110 °.
Is preferred. It is preferable to arrange both via a liquid crystal cell, but in this case, the crossing angle is 30 ° to 150 °.
° is preferred.

When the above-mentioned compensation film is incorporated between two polarizing plates, the stretching axes of the polarizing films are optimized, and the compensating film is attached using an adhesive. A protective film made of triacetyl cellulose is used before and after the polarizing plate, but the protective film on the liquid crystal cell side can be substituted with the optical rotatory film of the present invention.

[Method of Synthesizing Compound] Compound SK-25 was synthesized by the following route.

[0040]

[Chemical 15]

(I) Synthesis of compound (I) 300 ml of 12% hydrochloric acid was added to 27.4 g (0.2 mol) of p-aminobenzoic acid, and the internal temperature was 0 to 5 ° C while stirring under ice cooling.
Sodium nitrite 16.6g (0.24mol)
70 mol of water solution of was added dropwise. After stirring for 2 hours under ice cooling 3-
Methyl-N, N-diethylaniline 32.6 g (0.2
100 ml of 12% hydrochloric acid (mol) solution was added dropwise while maintaining the internal temperature at 5 to 10 ° C. After completion of the dropping, a solution of 164 g (2.0 mol) of sodium acetate in 800 ml of water was added to the reddish orange suspension, and the mixture was stirred for 2 hours. The precipitated solid was collected by filtration, washed with water, and air-dried to obtain compound (I). Yield 45 g (yield 72%) (ii) Synthesis of compound (II) To 10 g (0.032 mol) of compound (I), 11.5 g (0.096 mol) of thionyl chloride, 1 drop of N, N-dimethylformamide, and 300 ml of benzene was added and the mixture was heated under reflux for 2 hours. After allowing to cool to room temperature, the precipitated solid was collected by filtration,
It was washed with benzene and dried under reduced pressure to obtain the compound (II). Yield 7.6 g (yield 72%) (iii) Synthesis of Compound SK-25 (1R, 2R)-(-)-1,2-diaminocyclohexane 1.3 g (0.012 mol) in triethylamine 2.
4 g (0.024 mol) and 300 ml of THF were added, and 7.6 g of compound (II) was gradually added with stirring at room temperature. The precipitated hydrochloride was collected by filtration, the solvent of the filtrate was distilled off under reduced pressure with an evaporator, and then purified by silica gel column chromatography (eluent: methylene chloride / ethyl acetate = 1/1) to give compound SK-25. Obtained. Yield 4.9 g (58% yield) λmax = 400 nm ε = 68300

SK-35 was synthesized by the following route.

[0043]

[Chemical 16]

(I) Synthesis of Compound (III) Compound (III) was prepared by FM Hamer,
“Heterocyclic Compounds-Cyanine Soybean and Relayed Compounds (Heterocycli
c Compounds-Cyanine Dyes and Related Compounds) ”
Chapter 4, Chapter 5, Chapter 6, pages 86-119, published by John Wileyand Sons (1964), DM Starmer (DMSturmer)
Written by Heterocyclic Compounds-Special
Topics in Heterocyclic Chemistry
(Heterocyclic Compounds-Special Topics in Heterocy
clic Chemistry) ", Chapter 8, pp. 482-515,
It was synthesized based on the method described in John Wiley and Sons (1977). (ii) Synthesis of Compound (IV) Compound (IV) was synthesized according to the method of (ii) in the synthesis of SK-25. (iii) Synthesis of SK-35 Compound SK- was prepared according to the method of (iii) in the synthesis of SK-25.
35 was synthesized.

[0045]

Example 1 20% by weight of polycarbonate having a weight average molecular weight of 100,000
The compound SK-25 was mixed with the methylene chloride solution at a concentration of 1% by weight with respect to the polymer to prepare a polycarbonate solution for casting. Then, the above polymer solution was cast on a stainless steel band, dried until the residual solvent of the peeled film became 3%, and then uniaxially stretched under a temperature condition of 158 ° C. to obtain a polycarbonate birefringent film (E -1) was obtained.

Further, the above compounds SK-25 and SK-35 were respectively added to the polymer in 20% by weight methylene chloride solution of polycarbonate having a weight average molecular weight of 100,000 per 1 polymer.
A polymer solution for casting was prepared by mixing in a weight% concentration ratio. Then, the polymer solution was cast on a stainless steel band, dried until the residual solvent of the peeled film became 3%, and then uniaxially stretched under a temperature condition of 158 ° C. to obtain a polycarbonate birefringent film (E -2) was obtained.

Example 2 Styrene-based polymer having a weight average molecular weight of 400,000 ((A) styrene / butadiene copolymer (monomer copolymerization ratio 20/8)
0) to (B) styrene / acrylonitrile / α-methylstyrene (copolymerization ratio 60/20/20) (A):
(B) = graft polymerized at a ratio of 10:90) 2
The above compound P-2 was added to a 0 wt% methylene chloride solution.
5 was mixed with the polymer at a concentration of 1% by weight.
After that, it is cast on a stainless steel band and the residual solvent is 1%.
And then uniaxially stretched at a temperature of 110 ° C. to obtain a birefringent film (E-3).

Further, the compounds SK-25 and SK-35 were mixed with a 20% by weight methylene chloride solution of the styrene-based polymer having a weight average molecular weight of 400,000, respectively, at a concentration of 1% by weight with respect to the polymer. Then, it was cast on a stainless steel band, dried until the residual solvent became 3%, and then uniaxially stretched under a temperature condition of 105 ° C to obtain a birefringent film (E-4).

Comparative Example 1 20% by weight of polycarbonate having a weight average molecular weight of 100,000
The methylene chloride solution was cast on a stainless steel band, dried until the residual solvent of the peeled film became 3%, and then uniaxially stretched at a temperature of 158 ° C. to obtain a polycarbonate birefringent film (CO- 1)
Got

Comparative Example 2 A 20 wt% methylene chloride solution of the styrene polymer described in Example 2 having a weight average molecular weight of 400,000 was cast on a stainless steel band and dried until the residual solvent of the peeled film was 1%. And then stretched under the temperature condition of 110 ° C.,
A birefringent film (CO-2) was obtained.

Evaluation of Viewing Angle Dependence in Liquid Crystal Panel Evaluation was carried out with a liquid crystal panel of a black and white display using an STN liquid crystal cell having the structure shown in FIG. 1 (obtained by disassembling and removing the Toshiba word processor JW01). The birefringent film, E-1, E-2, E-3, E-4,
CO-1 and CO-2 were used as the retardation film of the liquid crystal panel of FIG. 1, and the liquid crystal panels of 1-9 of the structure shown in Table 1 were produced. The contrast ratio when viewed from the front of the obtained liquid crystal panel (luminance ratio in a driving state and a non-driving state),
The coloring state at that time, the vertical viewing angle at which the contrast ratio was 5: 1 or more, and the coloring state at the maximum viewing angle were evaluated and shown in Table 1.

[0052]

[Table 1]

Liquid crystal display devices (1, 2, 4, 5, 7, 8, 1) using the retardation films (E-1 to 4) of the present invention.
0) has high front contrast and no coloring. or,
Even if the viewing angle changes in the vertical direction, the contrast does not easily deteriorate, and there is almost no coloring, and the retardation film (CO
It can be seen that the display quality is far superior to that of the liquid crystal display device (3, 6, 9) using -1, 2). It was also confirmed that the same performance as E-1 was obtained when CO-1 and CO-2 were coated with a methanol solution of the optical rotatory substance such as the compound P-25 or P-75.

[Brief description of drawings]

FIG. 1 shows an arrangement of a liquid crystal panel.

[Explanation of symbols]

 BL: backlight P1: polarizing plate D1: retardation film LC: liquid crystal cell D2: retardation film P2: polarizing plate

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[Procedure amendment]

[Submission date] March 9, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

The optical rotatory dispersion of the optical rotatory substance is given by the Cotton effect, and the closer the chromophore is to the asymmetric center, the better.
Further, it has a close relationship with the absorption maximum wavelength (λ max) and the absorption intensity (ε) due to the chromophore, but when used in a liquid crystal display, the transmitted light must not be colored. Usually, a liquid crystal display of a liquid crystal display device has a backlight, and its light is R (630 nm), G (550 nm), B.
It has a bright line of (440 nm). It is preferred that there is substantially no absorption at said wavelength. Specifically, the transmittance at each wavelength is preferably 70% to 100%, and more preferably 90% or more. Further, it is preferable that the difference in transmittance at each wavelength is within 10%. Generally, the optical rotatory dispersion near λmax of absorption is large,
Further, the larger ε, the larger the optical rotatory dispersion. Therefore, λmax is different from the wavelengths of R, G, and B, and a chromophore having sharp absorption is preferable.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

[0027]

[Chemical 14]

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

Next, a method for producing the optical rotatory film of the present invention will be described. When a polymer having no optical rotatory power and an optical rotatory substance have a common solvent and are compatible with each other, a dope containing them is used to perform either casting in a molten state or solution casting. However, the optical rotatory film of the present invention can be produced. From the viewpoint of the stability of the optical rotatory substance and the smoothness of the surface of the film, solution casting is preferable. In the case of solution casting, the solvent is preferably a common solvent for the polymer and the optical rotatory substance, and the optical rotatory substance may be added in the state of dope, or may be added to the pipe immediately before casting.

Claims (6)

[Claims] 1. A compound having a π-π ^* transition, at which a plurality of chromophores are present at asymmetric positions and containing a compound which causes an asymmetric exciton interaction between the chromophores as an optically active substance. Polarizing film. 2. An optical rotatory film comprising the optical rotatory substance according to claim 1 and a polymer having no optical rotatory power. 3. The optical rotatory film according to claim 2, wherein the polymer has a positive intrinsic birefringence and is light transmissive. 4. The optical rotatory film according to claim 2, wherein the polymer has a negative intrinsic birefringence and is light transmissive. 5. A liquid crystal display device, wherein the optical rotation film according to claim 1, 2, 3 or 4 is disposed as a compensation film on at least one side of a liquid crystal cell. 6. The liquid crystal display device according to claim 5, wherein the liquid crystal display device has a backlight, and absorption of the optical rotation film is substantially absent at a wavelength of a bright line of light of the backlight.