KR100375503B1 - A photosensitive liquid crystal alignment layer for liquid crystal display element and liquid crystal display using thereit - Google Patents

Abstract

The present invention relates to a liquid crystal alignment film made of a photosensitive composition used in a liquid crystal display device, and more particularly, to a photoresist portion selected from the group consisting of a photoresist portion comprising a polymer backbone having a urethane structure and a cinnamoyl derivative. It relates to a photosensitive polymer liquid crystal alignment film for a liquid crystal display device constituted.

According to the liquid crystal alignment film of the present invention configured as described above it is possible to produce a liquid crystal alignment film having excellent photosensitivity, heat resistance and light stability, and also to save a lot of time for light irradiation in the optical alignment, production yield is improved Suitable for mass production

Description

Photosensitive polymer liquid crystal aligning film for liquid crystal display device and liquid crystal display device using the same TECHNICAL FIELD

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal alignment film made of a photosensitive composition used in a liquid crystal display device (LCD), and more particularly, to a photoresist non-reactive part including a polymer back bone having a urethane structure. And a photosensitive reaction part selected from the group consisting of cinnamoyl derivatives.

In general, a liquid crystal display device is formed by aligning a liquid crystal layer between two upper and lower substrates coated with an alignment layer and substrates thereof, and in order to obtain uniform brightness and high contrast ratio, the liquid crystal layer is not disturbed in the molecular axis direction. It is important to orient uniformly, but it is the liquid crystal aligning film which makes this possible.

The liquid crystal alignment layer is mainly made of an organic polymer material, and techniques such as rubbing, stretching, light irradiation, and the like are known as techniques for controlling the arrangement of liquid crystals using the liquid crystal alignment layer.

Among these, the most widely used industrially is the rubbing method, which forms microgrooves by rubbing a substrate coated with a polyimide alignment layer with an alignment cloth (mainly cloth) and using the liquid crystal to form a microgroove. This is a method of deriving the array direction. In addition, the rubbing method has a simple process, large area and high speed can be processed.

However, the above rubbing method has some serious disadvantages with regard to friction.

For example, first, since the shape of the microgrooves formed in the alignment layer varies according to the friction strength between the alignment cloth and the alignment layer, the arrangement of liquid crystal molecules becomes non-uniform, resulting in phase distortion and light scattering. ) Has the disadvantage that can occur.

Secondly, friction or static electricity due to friction may not only cause serious optical defects of the display, but also may cause breakage of the thin film transistor.

Third, there is a disadvantage in that it is difficult to adopt a multi domain process for solving a narrow viewing angle, which occupies a large part of various disadvantages of the liquid crystal display device.

In order to solve the above-mentioned disadvantages of the rubbing method, there is a photo-alignment method proposed as an orientation treatment method.

The photoalignment method is a method of controlling the alignment direction of liquid crystals by irradiating linearly polarized ultraviolet rays onto a substrate coated with a photoactive alignment agent.

The orientation direction has a certain direction with respect to the polarization direction of the linearly polarized ultraviolet light, the pretilt direction is changed by the incident direction of the irradiated ultraviolet light, the pretilt angle is changed by the irradiation energy.

In addition, since the optical alignment method is a non-contact method, it is a method that can fundamentally solve the problem of introducing impurities such as dust or generating static electricity, and is suitable for mass production due to the simple alignment treatment, and easily adjusts the pretilt angle by adjusting the amount of light. Can be controlled.

In the optical alignment method of imparting the pretilt direction using ultraviolet rays as described above, the liquid crystal display device is formed by rotating the polarizing plate at a predetermined angle according to a region and irradiating ultraviolet rays with different polarization directions to form domains having different alignment directions. It is possible to multi-domain process which can greatly improve the viewing angle.

However, the photo-alignment film used in the photo-alignment method known so far has disadvantages such as a lot of irradiation time due to low photosensitivity, weak anisotropy, light stability, low heat resistance. In addition, the disclination due to the alignment unevenness and interaction of the liquid crystal also remains a challenge.

Therefore, the present invention was devised to solve the above problems of the prior art, and an object of the present invention is to provide an alignment layer of a non-contact liquid crystal display device, and another object is a liquid crystal having excellent photosensitivity, heat resistance, and light stability. Another object of the present invention is to provide a liquid crystal alignment layer of a display element, and another object of the present invention is to provide a liquid crystal alignment layer applicable to liquid crystal display elements of various modes (TN, IPS, VA).

The photosensitive polymer liquid crystal alignment film for a liquid crystal display device of the present invention for achieving the above object is composed of a photoresist portion selected from the group consisting of a photoresist portion consisting of a polymer backbone having a urethane structure and a cinnamoyl derivative, which is described below. Have the same structural formula.

[Formula 1]

In Structural Formula 1, A may have a structure as shown in Structural Formula 2 below.

[Formula 2]

In Structural Formula 2, p and q may be independently 0 or 1 (but not both p and q may be 0), and A ₁ and A ₂ may be independently selected from 3 to 10 carbon cycles. Alkyl, cycloalkyl which may have at least one or more substituents, cycloalkenyl, an aromatic structure which may be absent or may have one or more substituents, said aromatic structure being a monocyclic structure of six carbons or nitrogen, ten Bicyclic structures of carbon or nitrogen, or tricyclic structures of 12 carbons or nitrogen. And A ₃ is O, C═O, alkyl having 1 to 10 carbon atoms, or cycloalkyl which may have at least one substituent, and the alkyl may be linear or branched alkyl.

In addition, B of Structural Formula 1 may be alkyl having 3 to 10 carbon atoms, alkyl which may have at least one or more substituents, alkenes that may have at least one substituent, cycloalkyl, cycloalkyl which may have at least one or more substituents. , Cycloalkenyl, cycloalkenyl which may have at least one or more substituents, an aromatic structure which may be free or having one or more substituents, the aromatic structure is a monocyclic structure of 6 carbon or nitrogen, 10 It may be a bicyclic structure made of carbon or nitrogen or a tricyclic structure made of 12 carbon or nitrogen.

In addition, n in Structural Formula 1 may be an integer between 10 and 500,000.

In the above formula 1, P is a photo active group (photo active group) can be represented by the following formula (3).

[Formula 3]

P, q and m in the formula 3 may be 0 or 1 independently of each other,

G can be expressed as ­G1­G2­G3­, ­G2­G3­, ­G1­G2­, or ­G2­, and if both p and q are 0, G should be expressed as ­G1­G2­ or ­G2­.

G1 and G3 may be independently of each other NHC (= 0), O, OC (= 0), COO or C (= 0) O and G2 is (CH ₂ ) _a , C _a H _2a OC _b H _2b , C _a H _2a COC _b H _2b , C _a H _2a OC (= O) C _b H _2b , C _a H _2a COOC _b H _2b , C _a H _2a CONR ₁ C _b H _2b , C _a H _2a R ₁ NC (O) C _b H _2b , C _a H _2a CH = CHC _b H _2b , C _a H _2a C≡CC _b H _2b , wherein a and b are each independently an integer between 1 and 6, and R ₁ Is hydrogen or lower alkyl;

E of formula 3 is O or NR ₁ , and R ₁ is hydrogen or lower alkyl;

X ₁ , X ₂ , X ₃ of Formula 3 are each independently H or 1 to 4 H is substituted with methyl, trifluoromethylmethoxy, trifluoromethoxy, halogen, cyano and / or nitro Can be;

X ₄ and Y of Formula 3 are each independently hydrogen, halogen, cyano, nitro, C _s H _{2s + 1} , C _s H _2s OC _t H _{2t + 1} , C _s H _2s COC _t H _{2t + 1} , C _s H _2s COOC _t H _{2t + 1} , C _s H _2s CONR ₁ C _t H _{2t + 1} , C _s H _2s OC (= O) C _t H _{2t + 1} , or C _s H _2s NR ₁ C _t H _{2t + 1} , C _s H _2s CH = CHC _t H _{2t + 1} , C _s H _2s C≡CC _t H _{2t + 1} , R ₁ is hydrogen or lower alkyl, and s is between 0 and 10 It is an integer, t is an integer between 1 and 10, and hydrogen (H) couple | bonded with carbon (C) is each independently replaceable with fluorine (F).

An embodiment of the present invention will be described below.

(First embodiment)

Polymer C is produced by the following reaction sequence.

0.1 mol of 4-fluorocinnamic acid is reacted with 0.2 mol of thionyl chloride (SOCl ₂ ) under a dimethylformamide (N, N-dimethyl formamide) catalyst to 4-fluorocinnamoyl. 4. Chloride (4-fluorocinnamoyl chloride) is obtained, which is 0.1 mol of 3, 5-dinitroaniline under 1 liter of CH ₂ Cl ₂ solvent and 0.1 mol of triethylamine base at room temperature. Intermediate A was obtained by reaction with (3,5-dinitroaniline), and 0.1 mol of the intermediate A was dissolved in 1 L of dimethylformamide, followed by addition of 10 ml of concentrated hydrochloric acid and 0.25 mol of iron (Fe). It reacted at 80 degreeC for 10 hours, and obtained intermediate B. Then, 0.1 mol of the intermediate B was dissolved in 300 ml of dimethylformamide, and then reacted with 0.1 mol of 1, 4-phenylenediisocyanate (1, 4-phenylene diisocyanate) at room temperature for 6 hours. The solution was added dropwise to 2 L of methanol to obtain Polymer C in the form of a precipitate.

The polymer C obtained by the reaction as described above was dissolved in 1% of dimethylformamide, spin coated onto a glass substrate on which ITO was deposited to a thickness of 500Å, and then heat-treated at 150 ° C. for 1 hour.

The heat-treated substrates were oriented by irradiating polarized ultraviolet rays of 1J / cm 2 using an OREL Co., Ltd. 500 Ｗ ultraviolet lamp, and then spreading 4 and 5 μm spacers on the surface and coating them with the same material. A cell was formed by adhering with ITO. And MLC6043 liquid crystal of Merck Co. was injected into the formed cell, and the resultant was heat-treated at 100 ° C. for 5 minutes.

The tilt of the completed cell was measured using a crystal rotation method, and the measured values are shown in Table 1.

(Second embodiment)

Polymer F is produced by the following reaction sequence.

0.1 moles of cinnamic acid is reacted with 0.2 moles of thionyl chloride (SOCl ₂ ) under a dimethyl formamide (N, N-dimethyl formamide) catalyst to obtain cinnamoyl chloride, This was reacted with 0.1 mol of 3, 5-dinitrphenol at room temperature under 1 L of methylene chloride (CH ₂ Cl ₂ ) solvent and 0.1 mol of triethylamine base. Intermediate D was obtained, and 0.1 mol of the intermediate D was dissolved in 1 L of dimethylformamide, 10 ml of concentrated hydrochloric acid and 0.25 mol of iron (Fe) were added, and the mixture was reacted at 80 DEG C for 10 hours. Got. Then, 0.1 mol of the intermediate E was dissolved in 300 ml of dimethylformamide, and then reacted with 0.1 mol of 1,4-diisocyanatobutane (1, 4-diisocyanatobutane) at room temperature for 6 hours, and then the reaction solution. Was added dropwise to 2 L of methanol to obtain Polymer F in the form of a precipitate.

The polymer F obtained by the reaction as described above was dissolved in 1% of dimethylformamide, spin coated onto a glass substrate on which ITO was deposited to a thickness of 500 kV, and then heat-treated at 150 ° C. for 1 hour.

The heat-treated substrates were oriented by irradiating polarized ultraviolet rays of 1J / cm 2 using a 500 Ｗ ultraviolet lamp manufactured by ORIEL Co., and then spreading 4 and 5 μm spacers on the surface and coating them with the same material. Adhesion was made with oriented ITO to form a cell. And MLC6043 liquid crystal of Merck Co. was injected into the formed cell, and the resultant was heat-treated at 100 ° C. for 5 minutes.

The tilt of the completed cell was measured using a crystal rotation method, and the measured values are shown in Table 1.

Type of material First embodiment Second embodiment Pretilt angle measurement 1.5 to 3.5 ° 0 to 1 °

As described above, according to the liquid crystal alignment film of the present invention, it is possible to produce a liquid crystal alignment film having excellent photosensitivity, heat resistance, and light stability.

In addition, it can save a lot of time for light irradiation in light alignment, so the production yield is improved, which is suitable for mass production.

The present invention is not limited to the above-described embodiments, and various modifications and changes may be made by those skilled in the art without departing from the spirit of the present invention and the equivalent scope of the claims to be described below. Of course it is possible.

Claims (4)

Photoresist ratio reaction unit consisting of a polymer backbone having a urethane structure as a liquid crystal alignment material of the photosensitive polymer material; And A photosensitive polymer liquid crystal alignment film for a liquid crystal display device, characterized by comprising a photosensitive reaction part selected from the group consisting of cinnamoyl derivatives. The method of claim 1, The polymer backbone having a urethane structure as the photosensitivity reaction part is made of the following Structural Formula 1, [Formula 1] A in Formula 1 has the same structure as in Formula 2 below, [Formula 2] P and q in the structural formula 2 is 0 or 1 independently of each other, Aromatic structure of the structural formula 2 A ₁ and A ₂ are independently of one another can have from 3 to 10 carbon atoms of cycloalkyl, or is cycloalkyl, cycloalkyl alkenyl, substituents which may have one or more substituents or one or more substituents Is, The aromatic structure is a monocyclic structure of 6 carbons or nitrogen, a bicyclic structure of 10 carbons or nitrogen, or a tricyclic structure of 12 carbons or nitrogen, A ₃ in Formula 2 is O, C═O, alkyl having 1 to 10 carbon atoms, or cycloalkyl which may have at least one substituent, In Formula 1, B is alkyl having 3 to 10 carbon atoms, alkyl having at least one or more substituents, alkenes having at least one substituent, cycloalkyl having at least one substituent, and cyclo having at least one substituent. Alkyl, cycloalkenyl, cycloalkenyl, which may have at least one or more substituents, an aromatic structure that may be absent or may have one or more substituents, The aromatic structure is a monocyclic structure of 6 carbons or nitrogen, a bicyclic structure of 10 carbons or nitrogen or a tricyclic structure of 12 carbons or nitrogen, N in the formula 1 is an integer between 10 and 500,000, the photosensitive polymer liquid crystal alignment film for a liquid crystal display device. The method of claim 1, The cinnamoyl derivative as the photosensitive reaction part is made of the following Structural Formula 3, [Formula 3] P, q, and m in the structural formula 3 is 0 or 1 independently of each other, G is represented by G1G2G3, G2G3, G1G2, or G2, and when both p and q are 0, G is G1G2 or G2 Expressed, G 1 and G 3 are each independently NHC (= 0), O, OC (= 0), COO or C (= 0) O, and G2 is (CH ₂ ) _a , C _a H _2a OC _b H _2b , C _a H _2a COC _b H _2b , C _a H _2a OC (= O) C _b H _2b , C _a H _2a COOC _b H _2b , C _a H _2a CONR ₁ C _b H _2b , C _a H _2a R ₁ NC (O) C _b H _2b , C _a H _2a CH = CHC _b H _2b , C _a H _2a C≡CC _b H _2b , A, b are each independently an integer of 1 to 6, R ₁ is hydrogen or lower alkyl, E in formula 3 is O or NR ₁ , R ₁ is hydrogen or lower alkyl, X ₁ in the formula 3, X _2, X ₃ are each independently H or a one to four H with methyl, methyl-methoxy, Romero ethoxy, halogen, cyano and / or nitro triple as a triple Can be substituted, X ₄ and Y in Formula 3 are each independently hydrogen, halogen, cyano, nitro, C _s H _{2s + 1} , C _s H _2s OC _t H _{2t + 1} , C _s H _2s COC _t H _{2t + 1} , C _s H _2s COOC _t H _{2t + 1} , C _s H _2s CONR ₁ C _t H _{2t + 1} , C _s H _2s OC (= O) C _t H _{2t + 1} , or C _s H _2s NR ₁ C _t H _{2t + 1} , C _s H _2s CH = CHC _t H _{2t + 1} , C _s H _2s C≡CC _t H _{2t + 1} , R ₁ is hydrogen or lower alkyl, s is between 0 and 10 An integer, t is an integer between 1 and 10, and hydrogen (H) bonded to carbon (C) can be independently substituted with fluorine (F), respectively. The photosensitive polymer liquid crystal alignment film for liquid crystal display device. In the liquid crystal display device, A liquid crystal display device comprising a liquid crystal alignment film containing the photosensitive polymer material according to any one of claims 1 to 3.