JP2000009936A - Production of optical compensation sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing an optical compensation sheet capable of inexpensively producing the optical compensation sheet which can impart a good visual field angle characteristic in a TN-LCD over the entire part of a display surface and has excellent heat resistance and mechanical strength. SOLUTION: A coating liquid contg. a polymerizable liquid crystal compd. is applied on a base and thereafter, the coating layer is heated in a heating region 3 to a liquid crystal forming temp. The coating layer is then cooled with a cooler 9 down to the solid-liquid transition temp. of the polymerizable liquid crystal compd. While the temp. of the coating layer is maintained at the solid-liquid transition temp. or below, the coating layer is irradiated with UV rays by a UV irradiation device 5, by which the polymerizable liquid crystal compd. is polymerized and cured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an optical compensatory sheet and an optical compensatory sheet, and more particularly to a method for producing an optical compensatory sheet useful for improving display contrast and viewing angle characteristics of display colors.

[0002]

2. Description of the Related Art CRT as a cathode ray tube type image display device
On the other hand, a liquid crystal display device having great advantages such as thinness, light weight, and low power consumption is generally used as a display device of a portable word processor or a personal computer. Currently popular liquid crystal display devices (hereinafter referred to as L
Most of the CDs use a twisted nematic liquid crystal. Such a liquid crystal display element generally comprises a liquid crystal cell and polarizing plates provided on both sides thereof. A display system using such a liquid crystal can be roughly classified into two systems, a birefringence mode and an optical rotation mode, depending on the operation mode.

A super-twisted nematic liquid crystal display device utilizing a birefringence mode (hereinafter referred to as ST)
The N-LCD uses a super twisted nematic liquid crystal having a twist angle exceeding 90 degrees and steep electro-optical characteristics. Therefore, such STN
-The LCD can display a large amount of data by time division driving. However, practical mode contrast can be obtained in STN-LCD in the yellow mode (yellow-green / dark blue) and blue mode (blue / light yellow). To obtain the black-and-white mode, a retardation plate (uniaxially stretched polymer film) is required. And a compensating liquid crystal cell). In the optical rotation mode, which is a display mode of the TN-LCD, high-speed response (several tens of milliseconds) and high contrast are obtained. Thus, the optical rotation mode has many advantages over the birefringence mode and other modes. However, TN-LCD uses STN-LC
Since no phase difference plate is provided unlike D, there is a problem that the display color and the display contrast tend to change depending on the angle when viewing the liquid crystal display device (viewing angle characteristics).

In order to improve the viewing angle characteristics of the TN-LCD (that is, to enlarge the viewing angle), it is proposed to provide a retardation plate (optical compensation sheet) between a pair of polarizing plates and a liquid crystal cell. Are described in JP-A-4-229828 and JP-A-4-258923. The retardation plate proposed in the above publication does not exert any optical action from directly in front of the liquid crystal cell since the retardation in the vertical direction is almost 0, but the retardation appears when tilted, It compensates for the phase difference generated in the liquid crystal cell by the action.

JP-A-6-75115, JP-A-4-75115
JP-A-1699539 and JP-A-4-276076 disclose an optical compensatory sheet having negative birefringence and an inclined optical axis. That is, the sheet is manufactured by stretching a polymer such as polycarbonate or polyester, and has a direction of the main refractive index that is inclined from the normal line of the sheet. Since the production of the above-mentioned sheet by the stretching treatment requires an extremely complicated stretching treatment, it is extremely difficult to produce a large-area optical compensation sheet by the disclosed method.

On the other hand, an optical compensation sheet using a liquid crystal polymer is also known. For example, JP-A-3-9326 and JP-A-3-291601 disclose an optical compensation sheet obtained by applying a polymer having liquid crystallinity to the surface of an alignment film on a support film.
However, a polymer having liquid crystallinity requires aging at a high temperature for a long time in order to be oriented, and therefore has a very low productivity and is not suitable for mass production. Japanese Patent Laid-Open No. 5-215
No. 921 discloses an optical compensation sheet (birefringent plate) comprising a support and a polymerizable rod-like compound having liquid crystallinity and positive birefringence. This optical compensation sheet is obtained by applying a solution of the polymerizable rod-like compound to a support and curing by heating. However, since the polymer having the liquid crystal property is optically positive uniaxial, the viewing angle can hardly be increased.

[0007] JP-A-6-214116 and JP-A-6-265728 propose an optical compensatory sheet comprising a support and a polymerizable liquid crystal compound having negative birefringence. This optical compensation sheet can improve the viewing angle of the TN-LCD. However, this optical compensatory sheet does not always have sufficient heat resistance and mechanical strength.
No. 7284 and JP-A-8-43624,
A coating liquid containing a discotic liquid crystal compound having a polymerizable group introduced into a side chain of a polymerizable liquid crystal compound having a negative refractive index (a discotic liquid crystal) is applied to a support, and the coating layer is disconematic of the discotic liquid crystal compound. A method has been proposed in which a discotic liquid crystal compound is crosslinked (polymerized and cured) by heating to a phase formation temperature and then irradiating the coating layer with ultraviolet rays or the like. The optical compensation sheet obtained by this manufacturing method improves the viewing angle of the TN-LCD, and is excellent in heat resistance and mechanical strength.

[0008]

Discotic liquid crystal compounds form a discotic nematic phase when the temperature exceeds the solid-liquid crystal transition temperature. It is known that the degree of orientational order of the discotic nematic phase changes continuously according to the temperature of the discotic liquid crystal compound, and that the higher the temperature of the discotic liquid crystal compound, the lower the degree of orientational order of the discotic nematic phase. . According to the study of the present inventors, it has been found that when the coating layer is irradiated with ultraviolet rays to polymerize and cure the discotic liquid crystal compound, the temperature of the coating layer increases. And
As a result of further study, the retardation (product of the intrinsic birefringence of the liquid crystal compound, the thickness of the optically anisotropic layer, and the degree of orientational order) of the optically anisotropic layer obtained by polymerizing and curing the liquid crystal compound was measured by irradiating ultraviolet rays. It has been found that, depending on the temperature of the coating layer at the time of polymerizing and curing the discotic liquid crystal compound, the retardation tends to decrease when the polymerization and curing are performed at a certain temperature or higher. The decrease in retardation can be dealt with by increasing the thickness of the optically anisotropic layer, whereby the viewing angle characteristics of the TN-LCD can be secured. However, in this case, the application amount of the coating liquid per unit increases, which is disadvantageous in cost.

Therefore, the object of the present invention is to
An optical compensatory sheet excellent in heat resistance and mechanical strength while maintaining good viewing angle characteristics in D over the entire display screen, that is, while maintaining the orientational order of the optically anisotropic liquid crystal layer. Is to provide a method of manufacturing an optical compensation sheet which can be manufactured at low cost.

[0010]

According to the present invention, after a coating solution containing a polymerizable liquid crystal compound is applied on a support, the coating layer is heated to a liquid crystal forming temperature, and then the coating layer is coated with the polymerizable liquid crystal compound. And cooling the coating layer to a temperature below the solid-liquid crystal transition temperature and irradiating ultraviolet rays while maintaining the temperature of the coating layer below the solid-liquid crystal transition temperature to polymerize and cure the coating layer.

Preferred embodiments of the method for producing an optical compensation sheet of the present invention are as follows. 1) The polymerizable liquid crystal compound is a discotic liquid crystal compound having a crosslinkable functional group. 2) After the coating layer is heated to a liquid crystal forming temperature, the coating layer is cooled at a cooling rate within a range of 1 to 1000 ° C./min to a temperature lower than the solid-liquid crystal transition temperature. 3) The time from cooling the coating layer to the solid-liquid crystal transition temperature or lower and irradiating ultraviolet rays to polymerize and cure the polymerizable liquid crystal compound is within a range of 0.1 to 1200 seconds. 4) The support is a transparent sheet having an alignment film, and a coating solution is applied to the alignment film surface.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing an optical compensatory sheet of the present invention, when the coating layer is irradiated with ultraviolet rays to polymerize and cure the discotic liquid crystal compound, the temperature of the coating layer is maintained below the solid-liquid crystal transition temperature. Therefore, the degree of orientational order of the discotech nematic phase does not change. Therefore, the retardation of the optically anisotropic layer obtained by the method for producing an optical compensation sheet of the present invention is discotic by irradiating the coating layer with ultraviolet rays while maintaining the temperature of the coating layer at or above the solid-liquid crystal transition temperature. The retardation is higher than the retardation of the optically anisotropic layer obtained by polymerizing and curing the liquid crystal compound. TN-
The retardation (Rth) in the thickness direction, which is particularly important in the optically anisotropic layer of the optical compensation sheet that provides viewing angle characteristics in LCD, is represented by the following equation. Rth = {(nx + ny) / 2-nz} × d (nx and ny represent the in-plane principal refractive index of the support, and nz
Represents the main refractive index in the thickness direction, d represents the thickness of the optically anisotropic layer, and the unit of the above formula is nm.) And the optically anisotropic layer obtained by the method for producing an optical compensation sheet of the present invention. The retardation in the thickness direction per unit thickness (Rth / d) satisfies the following condition. 0.04 <Rth / d Further, in the optically anisotropic layer obtained by the method for producing an optical compensation sheet of the present invention, the in-plane retardation variation is 2% or less in standard deviation.

FIG. 1 shows a method for producing the optical compensation sheet of the present invention.
Shown in Hereinafter, description will be made with reference to the drawings. The coating liquid containing the discotic liquid crystal compound extruded from the coating machine 2 is applied to the alignment film surface of the sheet 7 having the alignment film sent from the feeding machine 1. The coating layer is heated in a heating region 3 at a liquid crystal (discotic nematic phase) forming temperature, and the discotic liquid crystal compound forms a discotic nematic phase. Next, the coating layer is cooled in the cooling region 4 until the temperature of the coating layer becomes equal to or lower than the solid-liquid crystal transition temperature. The coating layer is irradiated with ultraviolet rays by the apparatus 5 to polymerize and cure the discotic liquid crystal compound to form an optically anisotropic layer.
Take up with.

By the heat treatment, the discotic liquid crystal compound forms a discotic nematic phase. The liquid crystal (discotic nematic phase) formation temperature may be a temperature at which a monodomain discotic nematic phase can be formed, and is preferably around a solid-liquid crystal transition temperature. The temperature variation of the heating region 3 is preferably within a range of ± 10 ° C., and more preferably within a range of ± 5 ° C. The heating time is preferably at least 1 minute or more, more preferably 2 minutes or more, in order to stably form a monodomain discotech nematic phase.

The temperature variation of the cooling region 4 is preferably within a range of ± 10 ° C., and more preferably within a range of ± 5 ° C. Further, the temperature of the cooling region only needs to be equal to or lower than the solid-liquid crystal transition temperature, and is preferably in the range of 25 to 50 ° C. The cooling rate of the coating layer is 1 to 1000
C./min., Preferably 5 ° C./min.
0 to 150 ° C./min. If the cooling rate is too slow, a columnar phase develops.

The ultraviolet irradiation lamp used for the ultraviolet irradiation device 5 is not particularly limited, and a mercury lamp, xenon, metal halide, or the like can be used. Moreover, the optimal dose by temperature, the type and the coating layer of the ultraviolet irradiation amount of the compound is preferably in the range of different but 100 to 2000 mJ / m ^2, more preferably in the range of 500~2000mj / m ^2.
Further, the time from cooling the coating layer to the solid-liquid crystal transition temperature or lower and irradiating the coating layer with ultraviolet rays is 0.1 to 1200.
It is preferable to carry out within the range of seconds. If the time until the polymerization and curing is too long, a columnar phase is developed. If the time is too short, the uniformity of the coating layer is low, and the variation in the in-plane retardation of the obtained optically anisotropic layer is large.

Representative examples of the discotic liquid crystal compound used in the present invention include, for example, C.I. Destr
ade et al., Mol. Cryst. Liq. C
ryst. 71, p. 111 (1981), benzene derivatives, triphenylene derivatives, truxene derivatives, phthalocyanine derivatives, B.I. Kohn
e, et al., Angew. Chem. 96 volumes, 70
Page (1984), and cyclohexane derivatives described in J. Am. M. J. Lehn et al. Am. Che
m. Soc. Chem. Comun. , P. 1794 (1
985); Research report by Zhang et al. Am.
Chem. Soc. 116: 2655 (1994)
The azacrown-based and phenylacetylene-based macrocycles described in (1) above are generally used, and these molecules are generally used as a mother nucleus, and a linear alkyl group, an alkoxy group, a substituted benzoyloxy group, or the like is radially formed as a side chain thereof. The substituted structure is not particularly limited as long as the molecule itself has negative uniaxiality and the optical axis is oriented obliquely to the substrate surface by the oblique alignment film.

In the present invention, after the discotic liquid crystal is aligned, the liquid crystal is cross-linked by irradiation with ultraviolet rays.
The heat resistance and mechanical strength of the optically anisotropic layer are improved (after crosslinking, the liquid crystal layer is a layer having discotic liquid crystals fixed thereon and having no liquid crystallinity). Therefore, a crosslinkable functional group (preferably a polymerizable double bond) must be provided to the side chain of the discotic liquid crystal. Examples of such a liquid crystal compound are already known, and are described in detail, for example, in JP-A-8-27284.

The alignment film of the transparent sheet having the alignment film used in the present invention has a role of controlling the liquid crystal molecules in the liquid crystal layer to an arrangement or an inclination suitable for the operation mode of the liquid crystal. As a method of forming the alignment film, there are a method of depositing silicon oxide (SiO) or an organic substance, a method of forming an LB film, and a method of rubbing a thin film of a polymer compound (material for forming an alignment film). In general, a method of rubbing a thin film of an alignment film forming material is used from the viewpoint of productivity, cost, and the like.

Examples of the alignment film forming material include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer,
Styrene / maleimide copolymer, polyvinyl alcohol, poly (N-methylolacrylamide), styrene / vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate Examples include polymers such as polymers, ethylene / vinyl acetate copolymers, carboxymethyl cellulose, polyethylene, polypropylene, and polycarbonate, and compounds such as silane coupling agents. Preferred examples of the polymer include polymers of polyimide, polystyrene, and styrene derivatives, gelatin, polyvinyl alcohol, and polyvinyl alcohol derivatives.

In particular, polyvinyl alcohol or a polyvinyl alcohol derivative has an excellent ability to uniformly align a liquid crystalline discotic compound. Examples of the polyvinyl alcohol derivative include an alkyl-modified polyvinyl alcohol. The alkyl group of the alkyl-modified polyvinyl alcohol preferably has 6 to 14 carbon atoms,
Furthermore, -S -, - C (CH 3) (CN) -, or,
Desirably, the compound is bonded to polyvinyl alcohol via —C (C ₂ H ₅ ) (CN) —. The alkyl-modified polyvinyl alcohol has an alkyl group in a terminal group, and preferably has a saponification degree of 80% or more and a polymerization degree of 200 or more. Further, polyvinyl alcohol having an alkyl group in the side chain is MP103 or MP20 manufactured by Kuraray Co., Ltd.
3. Any commercially available R1130 can be used.

The support of the optical compensation sheet of the present invention is not particularly limited as long as it is transparent. It is desirable that the transmittance of the visible light be 80% or more, and particularly that the material has optical isotropy when viewed from the front. Therefore, it is desirable that the support is manufactured from a material having a small intrinsic birefringence. As such a material, cellulose triacetate can be used. Even for materials with large intrinsic birefringence such as polycarbonate, polyarylate, polysulfone and polyether sulfone, conditions such as solution casting and melt extrusion, as well as stretching studies in the vertical and horizontal directions are appropriately set. By doing so, it can be used.

[0023]

EXAMPLES (Preparation of long transparent sheet having alignment film) Cellulose triacetate (Fujitac, manufactured by Fuji Photo Film Co., Ltd.) coated with a gelatin layer (0.1 μm thick)
A 5% by weight aqueous solution of a long-chain alkyl-modified polyvinyl alcohol (MP-203, manufactured by Kuraray Co., Ltd.) is applied on a thickness: 100 μm, width: 500 mm), dried with hot air at 80 ° C., and then rubbed. By performing the treatment, a sheet having an alignment film was formed.

(Example 1) (Preparation of coating liquid) Discotic liquid crystal (the following compound A) 325 g, compound A:

[0025]

Embedded image

Trimethylpropane EO-added triacetate (V360, Osaka Organic Chemical Co., Ltd.) 32 g, cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Company) 2 g, cellulose acetate butyrate (CAB551-0.2, yeast) 7 g of Man Chemical Co., 4 g of 2,4 diethylthioxanthone (Kamacure DETX-S, manufactured by Nippon Kayaku), and a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1
1 g was dissolved in 620 g of methyl ethyl ketone to prepare a coating solution. This coating solution is applied on a slide glass,
The change was observed with a polarizing microscope while heating, and as a result, the solid-liquid crystal transition temperature was 115 ° C and the liquid crystal-isotropic transition temperature was 150 ° C.

(Preparation of Optical Compensation Sheet) The above-mentioned coating solution was coated on a wire bar (#
3 bar), and the surface temperature of the coating layer is 125 ° C. ± 5 ° C.
The mixture was heated for 2 minutes while maintaining the temperature to form a discotec nematic phase. Next, after standing still in an atmosphere of 50 ° C. for 1 second, ultraviolet irradiation is performed using a high-pressure mercury lamp in this state, and an optical compensation having a 1.8 μm-thick layer containing a discotic compound (optically anisotropic layer) is performed. Created a sheet.

(Example 2) A discotech nematic phase was formed under the same conditions as in Example 1, and then at 90 ° C.
After standing for 20 seconds in this atmosphere, ultraviolet irradiation was performed using a high-pressure mercury lamp in this state to prepare an optical compensation sheet having an optically anisotropic layer having the same thickness.

Comparative Example 1 A coating solution was prepared in the same manner as in Example 1 except that the amount of methyl ethyl ketone was changed to 524 g. Then, the coating solution was applied on an alignment film of a sheet having an alignment film by a wire bar. A discotic nematic phase was formed under the same conditions as in Example 1 except that the coating was performed using (# 3 bar). Next, the temperature of the coating layer was set to 125 ° C.
Ultraviolet irradiation was performed using a high-pressure mercury lamp while maintaining the temperature at ± 5 ° C. to prepare an optical compensation sheet having a 2.0 μm-thick optically anisotropic layer.

(Evaluation) The optical compensatory sheets of the examples and comparative examples were each made up to 50 m, and the following evaluations were made. 1) The surface temperature of the coating layer when irradiating ultraviolet rays was measured.
The measurement was performed using an infrared radiation thermometer (IT2-50, manufactured by Keyence Corporation). Table 1 shows the results. 2) With respect to the optical compensation sheet obtained as described above, the surface including the rubbing axis and perpendicular to the surface of the different phase difference plate,
The retardation value was measured from all directions with an ellipsometer (AEP-100, manufactured by Shimadzu Corporation), and the optical characteristics of the support after removing the discotic compound in the measurement area were measured in the same manner. From these measurements, assuming a negative uniaxial index ellipsoid, the triaxial index n
x, ny, and nz were determined, and the retardation in the thickness direction per unit thickness (Rth / d) was determined. The measurement was performed at five points in the width direction for each 1 m of the optical compensation sheet. Table 1 also shows the results of the average value and the standard deviation. 3) TFT-type liquid crystal color television 6E manufactured by Sharp Corporation
-Remove the C3 polarizing plate, sandwich the liquid crystal cell,
The optical compensation sheet obtained in the example or the comparative example was mounted. Next, polarizing plates were attached to the outside so as to be orthogonal to each other, thereby producing a color liquid crystal display device. With respect to this color liquid crystal display device, white display and black display were performed, and the viewing angle at which the contrast ratio in the upper, lower, left, and right directions was 10: 1 was measured. That is, a rectangular wave voltage is applied to the obtained color liquid crystal display device, and the contrast from the front direction and the direction inclined upward / downward and left / right is measured by a spectrometer (LCD-LCD).
5000, manufactured by Otsuka Electronics Co., Ltd.) to determine the upper / lower and left / right viewing angles at which the contrast is 10. The evaluation was performed only for Example 1 and Comparative Example 1. Table 2 shows the results. In addition, Table 2 shows the evaluation results of a color liquid crystal display device in which the polarizing plates of the TFT type liquid crystal color television 6E-C3 manufactured by Sharp Corporation were peeled off and the polarizing plates were stuck so as to be orthogonal to each other without sandwiching the optical compensation sheet. Shown in

[0031]

[Table 1] Table 1 ────────────────────────────────── Surface temperature (° C) Rth / d Standard deviation ────────────────────────────────── Example 1 98 ± 5 0.049 1.3 Example 2 85 ± 5 0.050 1.4────────────────────────────────── Comparative Example 1 130 ± 5 0.0 045 2.5 mm

[0032]

[Table 2] Table 2 ────────────────────────────────── Vertical (degrees) Left and right (degrees) Remarks ─ ───────────────────────────────── Example 1 123 115 No unevenness occurs even when viewed obliquely. ─────────────────────────────── Comparative Example 1 130 120 Unevenness occurs when viewed obliquely ──────な し No sheet 50 70 No unevenness when viewed from an angle 斜 め─────────────────────────

In Table 1, when Examples 1 and 2 are compared with Comparative Example 1, the retardation in the thickness direction per unit (Rth / d) is larger in Examples 1 and 2. Therefore, although the thickness of the optically anisotropic layer is 1.8 μm in Example 1 and 2.0 μm, which is about 10% thicker in Comparative Example 1, the retardation in the thickness direction of the optically anisotropic layer ( Rt
h) is 88 nm in Example 1 and 90 nm in Comparative Example 1.
And the viewing angle characteristics were similarly good.

[0034]

According to the method for producing an optical compensatory sheet of the present invention, the temperature of the discotic liquid crystal compound can be maintained below the solid-liquid crystal transition temperature even when the coating layer is irradiated with ultraviolet rays to polymerize and cure the discotic liquid crystal compound. Therefore, the degree of orientational order of the discotec nematic phase does not change. Therefore, the retardation in the thickness direction per unit thickness of the optically anisotropic layer obtained by the method for producing an optical compensation sheet of the present invention is high, and its fluctuation is small. As described above, the optical compensatory sheet obtained by the method for producing an optical compensatory sheet of the present invention improves the viewing angle over the entire surface of the TN-LCD and hardly causes image unevenness. Also, since the retardation in the thickness direction per unit thickness of the optically anisotropic layer increases,
The thickness of the optically anisotropic layer can be reduced, and the optical compensation sheet can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a manufacturing process of an optical compensation sheet of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 feeder 2 coating machine 3 heating area 4 cooling area 5 ultraviolet irradiation device 6 winder 7 sheet with alignment film 8 heater 9 cooler

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2H049 BA06 BA26 BA42 BC02 BC05 BC09 BC22 2H091 FA11X FA11Z FB02 FC22 FC23 FC29 KA02 LA02 LA04 LA19 4F073 AA12 AA14 BA03 BA07 BA08 BA13 BA17 BA18 BA19 BA23 BA26 BA31 BB01 CA45 EA59 HA04 HA05 HA06 HA08 HA09 4F213 AA00 AA44 AH81 WA14 WA53 WA58 WA83 WA84 WA86 WA87 WB01 WB18

Claims (4)

[Claims] After coating a coating solution containing a polymerizable liquid crystal compound on a support, the coating layer is heated to a liquid crystal forming temperature, and then the coating layer is heated to a temperature below the solid-liquid crystal transition temperature of the polymerizable liquid crystal compound. And irradiating ultraviolet rays while maintaining the temperature of the cooled coating layer at or below the solid-liquid crystal transition temperature to polymerize and cure the polymerizable liquid crystal compound. 2. The method for producing an optical compensation sheet according to claim 1, wherein the polymerizable liquid crystal compound is a discotic liquid crystal compound having a crosslinkable functional group. 3. After heating the coating layer to a liquid crystal forming temperature,
The optical compensation according to claim 1, wherein the coating layer is cooled at a cooling rate within a range of 1 to 1000 ° C./min to a temperature equal to or lower than the solid-liquid crystal transition temperature. Sheet manufacturing method. 4. The time from cooling the coating layer to the solid-liquid crystal transition temperature or lower, and then irradiating ultraviolet rays to polymerize and cure the polymerizable liquid crystal compound is within a range of 0.1 to 1200 seconds. The method for producing an optical compensation sheet according to claim 1, wherein: