KR20010024952A - Film - Google Patents

Abstract

The present invention relates to an optical retardation film comprising a layer of an anisotropic polymer material having an optical axis substantially parallel to the plane of the layer. The present invention also relates to a method of manufacturing an optical retardation film, the use of an optical retardation film in a liquid crystal display, and a liquid crystal display device including a liquid crystal cell and an optical retardation film.

Description

Film {FILM}

Optical retardation films are used for optical modulation in various optical articles. For example, a quarter wave suppression film (QWF) can transform circularly polarized light into linearly polarized light. The optical retardation film can also be used as a compensator for improving the optical characteristics of a liquid crystal display, such as a contrast ratio or grayscale at a large viewing angle. As a particular application, there is a need for a birefringent optical film having an ideal optical axis parallel to the plane of the film, known as the A-plate.

As A-plates, uniaxially stretched films of granular isotropic or LC polymers have been proposed in the prior art. WO 97/03676 discloses an optical retardation film comprising a layer of an anisotropic polymer material having an optical axis with a relatively low inclination angle relative to the plane of the layer, which is prepared by coating a polymerizable mesogenic mixture on a substrate and arranging and curing the mixture Film.

However, when producing such an optical retardation film, it was difficult to obtain a two-dimensional arrangement of an anisotropic polymer material having a low inclination angle between the optical axis and the surface of the film, in particular, the inclination angle being close to zero or the inclination angle being almost zero.

Thus, useful A-plate optics, which can be used to enhance the optical properties of liquid crystal displays, are flexible films with large areas and are easy to fabricate in large dimensions and have nearly parallel optical axes with a substantially tilting angle of zero relative to the plane of the film Delayed films are still required.

One of the objects of the present invention is to provide such an optical retardation film. It is another object of the present invention to provide a method for producing such an optical retardation film. Other objects of the present invention are apparent to those skilled in the art from the following detailed description.

This object can be achieved by providing an optical retardation film according to the present invention.

The invention relates to an optical retardation film comprising an anisotropic polymer material layer having an optical axis substantially parallel to the plane of the layer, obtainable by a process comprising steps A), B), C) and D) It is about:

A) coating a polymeric mesogenic composition consisting essentially of the following materials a), b) and c) on a substrate in the form of a layer dissolved in an organic solvent at a concentration of 50% by weight or less;

a) from 10 to 50% by weight of one or two polymerizable mesogenic compounds of the formula (Ia) and from 5 to 35% by weight of one or two polymerizable mesogenic compounds of the formula (Ib);

In this formula,

W is H or CH _3,

n is an integer from 3 to 6,

R is alkyl or alkoxy having 1 to 8 carbon atoms,

b) from 15 to 60% by weight of polymerizable mesogenic compounds of the formula (II);

In this formula,

W is H or CH _3,

n is an integer from 3 to 6,

Z ¹ and Z ² are each independently -COO- or -OCO-,

X ¹ and X ² are each independently H or CH ₃ ,

c) 0.1 to 8% by weight of a photoinitiator;

B) arranging the polymerizable mesogenic composition in the same direction;

C) polymerizing the polymerizable mesogenic composition by exposure to UV light; And

D) selectively removing the substrate from the polymerized material, characterized in that it comprises the following steps I), II) and III):

(I) adding to the polymerizable mesogenic composition from 50 to 2500 ppm of a mixture of non-ionic fluoroalkyl-alkoxylate surfactants selected from the group consisting of (III) and (IV) before or during the step A)

C _n F _{2n + 1} SO ₂ N (C ₂ H ₅ ) (CH ₂ CH ₂ O) _x CH ₃

C _n F _{2n + 1} (CH ₂ CH ₂ O) _x H

In this formula,

n is an integer of 4 to 12, and x is an integer of 5 to 15.

II) using PET or TAC film as the substrate on which the polymerizable mesogenic composition is coated in step A) of the process;

III) rubbing the surface of the PET or TAC film adjacent to the polymerizable mesogenic composition prior to step A) of the process in a single direction or covering with a unidirectionally rubbed polyimide layer.

The present invention also relates to a method of manufacturing an optical retardation film as described above, the use of the optical retardation film in a liquid crystal display, and a liquid crystal display device including a liquid crystal cell and an optical retardation film.

The object of the present invention is an optical retardation film comprising a layer of an anisotropic polymer material having an optical axis approximately parallel to the plane of the layer, obtainable by a process comprising the steps A) to D) as described above.

Preferred embodiments of the present invention are the following materials:

An optical retardation film having an angle of inclination between the optical axis and the plane of the layer of said anisotropic polymer material is 0 to 1 deg.

The optical retardation obtainable by the process as described above, wherein the mixture of non-ionic fluoroalkyl-alkoxylate surfactants comprises 50 to 2500, preferably 100 to 1200 ppm of two or more compounds of formula (III) film.

The optical retardation obtainable by the process as described above, wherein the mixture of non-ionic fluoroalkyl-alkoxylate surfactants comprises 50 to 2500, preferably 800 to 1800 ppm of two or more compounds of formula (IV) film.

An optical retardation film obtainable by the process as described above, wherein in the compound of the formula (II), X ¹ is H, X ² is CH ₃ , Z ¹ is -COO-, and Z ² is -OCO-.

An optical retardation film obtainable by the process as described above, wherein W is H in the compounds of the formulas (Ia), (Ib) and (II).

An optical retardation film obtainable by the process as described above, wherein in step A) of the process the PET film is used as a substrate and the surface adjacent to the polymerizable mesogenic composition rubs in a single direction prior to step A).

Another object of the present invention is the preparation of an optical retardation film comprising a layer of an anisotropic polymer material whose optical axis is substantially parallel to the plane of the layer, said process comprising steps A) to D) as described above and hereinafter. Method.

Another object of the present invention is the use of an optical retardation film as described above and below in a liquid crystal display.

Another object of the present invention is a liquid crystal display device comprising a liquid crystal cell and an optical retardation film as described above and below.

The optical retardation of the optical retardation film of the present invention is preferably 20 to 600 nm, particularly preferably 25 to 170 nm, more preferably 300 to 600 nm.

The optical retardation film according to the present invention can be used in electro-optic displays, such as TN, super twisted nematic (STN), electrically controlled birefringence (ECB), optically compensated birefringence (OCB), DAP display based on twisted nematic (TN) effects such as deformation of aligned phases, vertically aligned nematic / cholesteric (VAN / VAC), optical mode interference (OMI) or super birefringence effect (SBE) Type, an in plane switching (IPS) type, a ferroelectric or antiferroelectric type display.

Also, for example, the optical retardation film of the present invention can be used as QWF together with a broadband reflective polarizer having an optical retardation film whose light-scattering film is approximately 0.25 times the center wavelength of the wavelength band reflected by the reflective polarizer.

The optical retardation film of the present invention comprises a layer of polymerized mesogenic material and is characterized by a remarkably high birefringence. Also, for example, the optical properties of optical retardation films such as birefringence properties can be controlled by modifying the type and ratio of polymerizable mesogenic compounds in the polymeric material.

The optical retardation film according to the present invention comprises a layer of an anisotropic polymer having a main optical axis substantially parallel to the plane of the layer. The inclination angle between the optical axis of the layer and the surface of the layer is preferably 0 to 1 degree, particularly 0 to 0.5 degree, and more preferably 0 to 0.3 degree. Particularly preferably, the inclination angle is substantially zero.

The inclination angle of the optical retardation film of the present invention mentioned above or below should be understood as the inclination angle of the entire film, which is the average inclination angle in other regions of the film. The inclined angle thus defined does not have to be equal to the inclination angle at the outer surface of the film, i.e. at the atmospheric surface, and / or the inclination angle at the inner surface of the film, i.e. the surface adjacent to the substrate on which the film is produced.

The optical retardation film of the present invention can be produced by coating a polymerizable mesogenic composition on a substrate in the form of a layer, arranging the material, and polymerizing the arranged material.

As the substrate, PET (polyethylene terephthalate) or TAC (triacetylcellulose) film is used. Particularly preferably, a PET film is used as a substrate. The PET film is commercially available, for example, under the trade name Melinex from ICI. TAC films are commercially available, for example, from Lonza AG (Switzerland) or Fuji Film (Japan).

In the process of the present invention, the two-dimensional arrangement in the coating layer of the polymerizable mesogenic composition, wherein the polymerizable mesogenic molecules in the composition are arranged substantially parallel to the plane of the layer and have a relatively low inclination angle with respect to the plane of the layer, That is, the orientation can be obtained particularly by the following steps.

Using a PET or TAC substrate;

Adding a surfactant to the polymerizable mesogenic composition; And

Rubbing the surface of the substrate or covering the substrate with a polyimide layer and rubbing the polyimide layer before coating the polymerizable composition on the substrate.

The surfactant used in the process of the present invention is a mixture of nonionic fluoroalkoxylate surfactants selected from formulas (III) and (IV).

C _n F _{2n + 1} SO ₂ N (C ₂ H ₅ ) (CH ₂ CH ₂ O) _x CH ₃ (III)

C _n F _{2n + 1} (CH ₂ CH ₂ O) _x H (IV)

Wherein n is an integer from 4 to 12 and x is an integer from 5 to 15.

When such a surfactant is used, a polymerized film having a very low inclination angle can be produced.

Surfactants of the formula (III) are commercially available under the trade names Fluorad 171 (3M) and Zonyl FSN (DuPont).

The amount of surfactant is preferably 500 to 2500 ppm, especially 1000 to 2500 ppm, very preferably 1500 to 2500 ppm.

In addition to the above-described methods, obtaining a low tilt angle and parallel arrangement also depends on the friction angle, i.e., the principal rubbing direction and the angle between the main optical axes of the respective substrate or polyimide layers. Preferably in a single direction substantially parallel to the main optical axis of the substrate.

Examples of the friction method are friction rolls or frictional rolls which are applied by a flat bar or, in each case, one or two rollers are selectively covered with a friction cloth, for example, a rapid spinning roller Or by positioning the substrate between the two rollers.

It may also be rubbed by covering the substrate at least partially at a predetermined angle around the roller coated with a rubbing cloth.

All the molasses of the friction cloth can be used for those applications known to those skilled in the art. For example, a commercially available standard type of velvet may be used as the friction cloth.

The performance of the substrate to induce alignment in the polymerizable mesogenic composition coated on the substrate after rubbing of the substrate is determined by the friction pressure, the friction speed and the rotational speed of the roller, the tension on the friction roller circumference and the substrate, And also on the process parameters of the friction process.

The friction length in the friction process of the preferred embodiment as described above is preferably 0.2 to 5 m, especially 0.5 to 3 m, most preferably 1.0 to 2.5 m.

The polymerizable mesogenic composition is cured by photopolymerization which is carried out by decomposing under UV radiation to form free radicals to expose the composition to UV light in the presence of a UV absorbing photoinitiator which initiates the polymerization reaction.

The polymerization can be carried out in air or under an inert gas, such as nitrogen gas. For example, a commercially available photoinitiator Irgacure 906 can be used for curing in air, but curing under a nitrogen gas is suitable, for example, commercially available Irgacure 651 or 184 (all manufactured by Ciba Geigy AG).

The amount of photoinitiator in the polymerizable mesogenic composition is from 0.1 to 8% by weight, preferably from 0.5 to 6% by weight, most preferably from 1 to 5% by weight of the total mixture.

The polymerizable mesogenic composition is preferably dissolved in an organic solvent before being coated on the substrate. Suitable solvents are preferably organic solvents such as methyl ethyl ketone, toluene, cyclohexanone or cyclopetanone, or mixtures of two or more of such solvents, which are used in conjunction with co-solvents such as xylene or isopropyl alcohol.

In order to obtain a polymer film having good alignment, the polymerization reaction must be carried out on the liquid crystal of the polymerizable mesogenic composition. Preferably, the curing temperature should be at least 40 占 폚 lower than the clearing temperature of the polymerizable mesogenic composition. Particularly preferably, the curing temperature is 30 to 60 占 폚.

Preferably, high-pressure or medium-pressure UV light having a radiation wavelength of 250 nm to 420 nm, especially 320 nm to 390 nm, is used.

As a source of the chemical beam, for example, a single UV lamp or a set of UV lamps may be used. When using high lamp power, the curing time can be reduced. The radiation produced by the lamp used in the present invention is preferably 0.01 to 100 mW / cm 2, particularly preferably 10 to 50 mW / cm 2.

The curing time according to the present invention is preferably not more than 1 minute, particularly preferably less than 30 seconds, and most preferably less than 5 seconds.

The thickness of the optical retardation film of the present invention obtainable by the above-described method is preferably 0.5 to 30 占 퐉, particularly 0.5 to 20 占 퐉, and most preferably 0.5 to 15 占 퐉.

The polymerizable mesogenic compositions used to prepare the optical retardation films of the present invention include the following polymerizable mesogenic compounds a) and b):

a) from 10 to 50% by weight of one or two polymerizable mesogenic compounds of formula (Ia) and from 5 to 35% by weight of one or two polymerizable mesogenic compounds of formula (Ib);

(Ia)

(Ib)

In this formula,

W is H or CH _3,

n is an integer from 3 to 6,

R is alkyl or alkoxy having 1 to 8 carbon atoms,

b) from 15 to 60% by weight of a polymerizable mesogenic compound of formula (II);

(II)

In this formula,

W is H or CH _3,

n is an integer from 3 to 6,

Z ¹ and Z ² are each independently -COO- or -OCO-,

X ¹ and X ² are each independently H or CH ₃ .

Preferably, a composition comprising a compound of formula (Ia), a compound of formula (Ib) and a compound of formula (II) is used.

In formula (Ia), R is preferably straight chain alkyl.

In the formulas (Ia), (Ib) and (II), W is preferably H.

In the formula (II), preferably, X ¹ represents H and X ² represents CH ₃ .

By varying the concentration of the bifunctional mesogenic compound of the formula (II) and the concentration of the monofunctional compound of the formula (Ia) and (Ib), the cross-linking density of the polymer film can be influenced. Thus, the properties of the film such as optical parameters and their temperature dependence, glass transition temperature, thermal and mechanical stability and solvent resistance can be controlled.

The amount of the compound of formula (Ia) in the polymerizable mesogenic composition is preferably 20 to 45% by weight, especially 30 to 40% by weight, based on the total mixture.

The amount of the compound of formula (Ib) is preferably 10 to 30% by weight, especially 15 to 25% by weight, based on the weight of the whole mixture.

The amount of the compound of the formula (II) is preferably 20 to 55% by weight, especially 35 to 50% by weight, based on the weight of the whole mixture.

The polymerizable mesogenic compounds of the formulas (Ia), (Ib) and (II) are described in the literature cited in standard studies of organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart Can be carried out by methods known to those skilled in the art. Compounds of formula (II) are described, for example, in D.J. Broer et al., Makromol. Chem. 190, 3201-3215 (1989). Compounds of formula (Ia) are disclosed in WO 97/00843.

Those skilled in the art will appreciate that the present invention may be fully utilized without any additional effort, by referring to the above detailed description. Accordingly, the following examples are illustrative only and are not intended to limit the scope of the invention.

In the above and following examples, all temperatures are in ° C unless otherwise stated, all parts and percentages are parts by weight and% by weight.

Example A: Comparative Example

The following polymerizable compositions are prepared as follows.

Compound (1) 45%

Compound (2) 35%

Compound (3) 20%

(One)

(2)

(3)

The compounds (1) to (3) Broer et al., Makromol. Chem 190, 3201-3215 (1989) and WO 97/00843.

To this polymerizable composition was added 6% by weight of the radical photoinitiator Irgacure 906 (manufactured by Ciba Geigy). The polymerizable composition comprising the photoinitiator was then dissolved in an organic solvent mixture of 2: 1: 1 toluene / xylene / isopropyl alcohol at a concentration of 20% by weight. The solution was filtered to remove impurities and small particles.

Two sheets of PET (Melinex 401, ICI) were rubbed in a single direction with a flat, polished aluminum bar. The friction length was set to about 1000 mm for the first sheet and 2000 mm for the second sheet.

The solution was coated with a film having a thickness of about 12 占 퐉 in each of the first and second PET sheets, and the solvent was evaporated at 55 占 폚. The mixture was then cured in air at 30 to 40 DEG C for several seconds by irradiation with UV light having a wavelength of 360 mW / cm < 2 > and radiation. In this way, two polymer films 1A and 2A were obtained which could be used as optical retardation films.

Film A1 was obtained on an PET sheet having a 1000 mm friction length, and film A2 was obtained on an PET sheet having a friction length of 2000 mm.

Example B

Prior to dissolving the polymerizable composition in the organic solvent mixture, 1000 ppm of a non-ionic fluorocarbon surfactant Fluorad FC 171 (3M) was added to each polymerizable composition, as described in Example A to provide two Polymer films B1 and B2 were prepared.

Film B1 was produced on an PET sheet having a 1000 mm friction length, and film B2 was produced on an PET sheet having a friction length of 2000 mm.

Usage Example

The photoconductivity R of films A1, A2, B1 and B2 of Examples A and B was measured at various angles of incidence angle &thetas; with respect to the direction of rubbing in an Olympus polarizing microscope using a Berek compensator. For this measurement, each film was removed from the PET substrate, adhered to the TAC substrate, and placed on a glass slide. The results are shown in Table 1 below.

Table 1: Optical coupling at various incident angles θ R (nm)

The optical transparency R of the optical retardation film of the present invention, which depends on the incident angle of light? And the inclination angle? Between the optical axis of the film and the plane of the film, can be expressed as a product of birefringence? N and film thickness d according to the following equation have.

(One)

In this formula, Is the birefringence of the film, and is defined as follows.

(2)

Where n _e and n _o respectively represent ideal refraction and normal refraction of the polymerized mesogenic material, respectively.

The values of n _e and n _o can be measured using an Abbe refractometer, Can be measured at various incident angles? As described above.

Therefore, the average inclination angle [phi] for the optical retardation film of the present invention described in Examples A and B having the thickness d can be expressed by the following formula: _e and n _o .

For polymer films A1, A2, B1 and B2, n _e measured with an Abbe refractometer is 1.64 and n _o is 1.50. R values for various incident angles? Are shown in Table 1. The average inclination angle? Is shown in Table 2 below.

Table 2: Tilt angles of optical retardation films of Examples A and B

The above results show that in the process of the present invention using a surfactant the tilt angle is reduced to almost zero and the quality of the two-dimensional orientation of the polymerized mesogenic material can be obtained with high optical film.

The above examples can be successfully repeated by replacing generally or specifically described reactants or by adjusting the conditions of the present invention to those used in the above examples.

From the above detailed description, those skilled in the art can easily ascertain the main points of the present invention and can apply various changes and modifications of the present invention to various uses and conditions without departing from the spirit and scope of the present invention.

Claims (13)

An optical retardation film comprising an anisotropic polymeric material layer having an optical axis substantially parallel to the plane of the layer, obtainable by a process comprising steps A), B), C) and D) A) a step of coating a polymeric mesogenic composition consisting essentially of a), b) and c), in a layer form, on a substrate in an organic solvent at a concentration of 50% by weight or less; a) from 10 to 50% by weight of one or two polymerizable mesogenic compounds of formula (Ia) and from 5 to 35% by weight of one or two polymerizable mesogenic compounds of formula (Ib); (Ia) (Ib) In this formula, W is H or CH _3, n is an integer from 3 to 6, R is alkyl or alkoxy having 1 to 8 carbon atoms, b) from 15 to 60% by weight of a polymerizable mesogenic compound of formula (II); (II) In this formula, W is H or CH _3, n is an integer from 3 to 6, Z ¹ and Z ² are each independently -COO- or -OCO-, X ¹ and X ² are each independently H or CH ₃ , c) 0.1 to 8% by weight of a photoinitiator; B) arranging the polymerizable mesogenic composition in the same direction; C) polymerizing the polymerizable mesogenic composition by exposure to UV light; And D) selectively removing the substrate from the polymerized material, characterized in that it comprises the following steps I), II) and III): (I) adding to the polymerizable mesogenic composition from 50 to 2500 ppm of a mixture of non-ionic fluoroalkyl-alkoxylate surfactants selected from the group consisting of (III) and (IV) before or during the step A) C _n F _{2n + 1} SO ₂ N (C ₂ H ₅ ) (CH ₂ CH ₂ O) _x CH ₃ (III) C _n F _{2n + 1} (CH ₂ CH ₂ O) _x H (IV) In this formula, n is an integer of 4 to 12, and x is an integer of 5 to 15. II) using PET or TAC film as the substrate on which the polymerizable mesogenic composition is coated in step A) of the process; III) rubbing the surface of the PET or TAC film adjacent to the polymerizable mesogenic composition prior to step A) of the process in a single direction or covering with a unidirectionally rubbed polyimide layer. The film of claim 1 wherein the angle of inclination between the optical axis and the plane of the anisotropic polymeric material layer is between 0 and 1 degrees. 3. A film according to claim 1 or 2, characterized in that the mixture of non-ionic fluoroalkyl-alkoxylate surfactants comprises from 100 to 1200 ppm of at least two compounds of formula (III). 4. A film according to any one of claims 1 to 3, characterized in that the mixture of non-ionic fluoroalkyl-alkoxylate surfactants comprises from 800 to 1800 ppm of at least two compounds of formula (IV). The film according to any one of claims 1 to 4, wherein in the compound of the formula (II), X ¹ is H, X ² is CH ₃ , Z ¹ is -COO- and Z ² is -OCO-. . 6. The film according to any one of claims 1 to 5, wherein W is H in the formulas (Ia), (Ib) and (II). Method according to any one of claims 1 to 6, wherein the PET film is used as a substrate in step A) of the process and the surface of the PET film adjacent to the polymerizable mesogenic composition is rubbed in a single direction before step A) ≪ / RTI > A method for producing an optical retardation film according to any one of claims 1 to 7. Use of an optical retardation film according to any one of claims 1 to 7 in a liquid crystal display. A liquid crystal display device comprising a liquid crystal cell and an optical retardation film according to any one of claims 1 to 7. A film comprising a layer of an anisotropic polymer material having an optical axis substantially parallel to the plane of the layer, obtainable by a process comprising steps A), B), C) and D) A) coating a polymeric mesogenic composition comprising the following materials a), b) and c) on a substrate in the form of a layer dissolved in an organic solvent at a concentration of 50% by weight or less; a) from 10 to 50% by weight of one or two polymerizable mesogenic compounds of formula (Ia) and from 5 to 35% by weight of one or two polymerizable mesogenic compounds of formula (Ib); (Ia) (Ib) In this formula, W is H or CH _3, n is an integer from 3 to 6, R is alkyl or alkoxy having 1 to 8 carbon atoms, b) from 15 to 60% by weight of a polymerizable mesogenic compound of formula (II); (II) In this formula, W is H or CH _3, n is an integer from 3 to 6, Z ¹ and Z ² are each independently -COO- or -OCO-, X ¹ and X ² are each independently H or CH ₃ , c) 0.1 to 8% by weight of a photoinitiator; B) arranging the polymerizable mesogenic composition in the same direction; C) polymerizing the polymerizable mesogenic composition by exposure to UV light; And D) selectively removing the substrate from the polymerized material, characterized in that it comprises the following steps I), II) and III): (I) adding to the polymerizable mesogenic composition from 50 to 2500 ppm of a mixture of non-ionic fluoroalkyl-alkoxylate surfactants selected from the group consisting of (III) and (IV) before or during the step A) C _n F _{2n + 1} SO ₂ N (C ₂ H ₅ ) (CH ₂ CH ₂ O) _x CH ₃ (III) C _n F _{2n + 1} (CH ₂ CH ₂ O) _x H (IV) In this formula, n is an integer of 4 to 12, and x is an integer of 5 to 15. II) using PET or TAC film as the substrate on which the polymerizable mesogenic composition is coated in step A) of the process; III) rubbing the surface of the PET or TAC film adjacent to the polymerizable mesogenic composition prior to step A) of the process in a single direction or covering with a unidirectionally rubbed polyimide layer. A film obtainable by a process comprising the following steps A), B), C) and D): A) coating a polymeric mesogenic composition consisting of the following materials a), b) and c) on a substrate in the form of a layer by dissolving it in an organic solvent at a concentration of 50% by weight or less; a) from 10 to 50% by weight of one or two polymerizable mesogenic compounds of formula (Ia) and from 5 to 35% by weight of one or two polymerizable mesogenic compounds of formula (Ib); (Ia) (Ib) In this formula, W is H or CH _3, n is an integer from 3 to 6, R is alkyl or alkoxy having 1 to 8 carbon atoms, b) from 15 to 60% by weight of a polymerizable mesogenic compound of formula (II); (II) In this formula, W is H or CH _3, n is an integer from 3 to 6, Z ¹ and Z ² are each independently -COO- or -OCO-, X ¹ and X ² are each independently H or CH ₃ , c) 0.1 to 8% by weight of a photoinitiator; B) arranging the polymerizable mesogenic composition in the same direction; C) polymerizing the polymerizable mesogenic composition; And D) optionally comprising steps I), II) and III) of: removing the substrate selectively from the polymerized material; (I) adding to the polymerizable mesogenic composition from 50 to 2500 ppm of a mixture of non-ionic fluoroalkyl-alkoxylate surfactants selected from the group consisting of (III) and (IV) before or during the step A) C _n F _{2n + 1} SO ₂ N (C ₂ H ₅ ) (CH ₂ CH ₂ O) _x CH ₃ (III) C _n F _{2n + 1} (CH ₂ CH ₂ O) _x H (IV) In this formula, n is an integer of 4 to 12, and x is an integer of 5 to 15. II) using PET or TAC film as the substrate on which the polymerizable mesogenic composition is coated in step A) of the process; III) rubbing the surface of the PET or TAC film adjacent to the polymerizable mesogenic composition prior to step A) of the process in a single direction or covering with a unidirectionally rubbed polyimide layer. A layer of an anisotropic polymer material having an optical axis substantially parallel to the plane of the layer.