MXPA97010154A

MXPA97010154A - Optical alignment composition formed alignment layer using the same and a liquid crystal display device which has the alineamine layer

Info

Publication number: MXPA97010154A
Application number: MXPA/A/1997/010154A
Authority: MX
Inventors: Yu Hansung; Chae Byunghoon
Original assignee: Samsung Display Devices Co Ltd
Priority date: 1996-12-17
Filing date: 1997-12-15
Publication date: 1998-11-12

Abstract

An optical alignment composition, a forming layer formed by using it with excellent thermal stability, and an LCD having the alignment layer are provided. The optical alignment composition includes a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8. In this way, one can obtain an optical alignment composition and an alignment layer each having excellent thermal stability and alignment property while adopting an optical, non-destructive alignment method. Therefore, an LCD can be obtained with improved performance

Description

COMPOSITION OF OPTICAL ALIGNMENT, FORMED ALIGNMENT LAYER USING THE SAME AND A VISUALIZATION DEVICE T) F. LIQUID CRYSTAL WHICH HAS THE ALIGNMENT LAYER FIELD OF THE INVENTION The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an optical alignment composition, an alignment layer formed using the optical alignment composition, and an LCD having the optical alignment layer. alignment.

BACKGROUND OF THE INVENTION In general, a liquid crystal has an intermediate property of a liquid and a solid that has the fluidity of a liquid and that has the optical property of a solid, and can be changed in its optical anisotropy by an electric field or heat. A liquid crystal display (LCD) device uses such properties. FIGURE 1 is a sectional view of a general LCD. With reference to FIGURE 1, the transparent electrodes 3 and 3 'made of oxide of REF: 26470 tin of indium (ITO) is formed on a pair of transparent substrates 2 and 2 'made of glass. The isolation layers 4 and 4 'and alignment layers 5 and 5' for the alignment of the liquid crystals are formed sequentially on the transparent electrodes 3 and 3 '. A spacer 6 for maintaining a constant cell opening is interposed between the alignment layers 5 and 5 '. A liquid crystal material is injected into the opening of the cell to form a liquid crystal layer 7. Polarization plates 1 and 1 'are provided to polarize the incoming and transmission lights on the outside of the substrates 2 and 2' . One of the determining factors in the performance of an LCD is an appropriate alignment of liquid crystals. Alignment layers are generally used for the purpose of aligning liquid crystals appropriately. Among these, conventionally, the alignment layer formed by rubbing or polishing a polymer layer has been widely used. However, according to the friction or polishing treatment, dust or static electricity can be generated due to mechanical contact between a polishing cloth and the alignment layer.

In this way, in order to solve the problem caused by a polished technology, a technology has been developed to solve the problem that has arisen. Optical, non-destructive alignment. According to this technology, polarized light is irradiated within a layer of photopolymer alignment, which causes anisotropic light-curing. As a result, liquid crystal molecules align uniformly. As the material of a photopolymer alignment layer, a polycinating agent such as PVCN (polyvinyl acetate) or PVMC (polyvinyl etoxicinamate) has been used. However, such polymers have poor thermal stability, although they have an excellent optical alignment property. In other words, the thermal stability of an alignment layer depends on the polymer, which depends on a vitreous transition temperature and crosslink density. Since policinamate in general has a vitreous transition temperature of 100 ° C or less and it is difficult to subject a photoreaction of 50% or more in a solid state, the increase in crosslink density is limited, which decreases the thermal stability of the alignment layer.

BRIEF DESCRIPTION OF THE INVENTION In order to solve the above problem (s), it is an object of the present invention to provide an optical alignment composition having excellent thermal stability. It is another object of the present invention to provide an alignment layer formed of an optical alignment composition having excellent thermal stability. It is still another object of the present invention to provide a liquid crystal display (LCD) device having the alignment layer. Therefore, to achieve the first objective, an optical alignment composition is provided which includes a ultifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8. The second objective of the present invention is achieved by an alignment layer that includes a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8. A third objective of the present invention is achieved by an LCD having an alignment layer that includes a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8. It is preferable that the multifunctional cinnamate compound have two to four cinnamate groups and be selected from the group consisting of alkyldiol dicynamate of 2 to 6 carbon atoms, alkyltriol tricinamate of 2 6 carbon atoms and alkyl tetrahydrate tetracinamate of 2 to 6. carbon atom. Although the cinnamate group containing the polymer is not specifically restricted, it is preferably selected from the group consisting of poly (vinylcinnamate) (PVCi), poly (vinylmethoxycinnamate) (PVMC) and polyimide having a cinnamate group in its chain side, and the weight average molecular weight thereof is preferably 5,000 to 200,000. In the present invention, the mixing ratio of the cinnamate compound to the polymer-containing cinnamate group is preferably in the range of 1: 9 to 2: 8. This is because excellent thermal stability and o-ring alignment are exhibited within the range.

BRIEF DESCRIPTION OF (THE) DRAWING (S) The above objects and advantages of the present invention will become more apparent when describing in detail a preferred embodiment thereof with reference to the accompanying drawing in which: FIGURE 1 is a sectional view of a general liquid crystal display device.

DESCRIPTION OF THE PREFERRED MODALITY (S) (S) In the present invention, there is provided an optical alignment composition having excellent thermal stability, an alignment layer formed using it, and an LCD having the alignment layer. Now, the manufacturing method of the same will be described. First, as an example of the multifunctional cinnamate compound, pentaerythritol tetracinate is produced by mixing pentaerythritol and cinnaoyl chloride with tetrahydrofuran and adding pyridine thereto and reacting the resultant. The multifunctional cinnamate compound produced and the polymer-containing cinnamate group are mixed in a weight ratio of 1: 9 to 2: 8 and mixed with an appropriate sol to produce an optical alignment composition. At the same time, as the polymer-containing cinnamate group, PVCi, PVMC or polyimide having a cinnamate group in its side chain can be used, and it is preferable that a polymer having a weight average molecular weight of 5,000 to 200,000 is used. . The solvent is preferably selected from N-methylpyrrolidone (NMP), dimethylformamide (DMF) and butylcellosolve, although it is not specifically restricted thereto. The composition is coated on two glass substrates where the electrodes are formed, respectively, and then the solvent is dried to produce an alignment layer. Subsequently, linear polarized light is irradiated within the alignment layer for a photoreaction. Then, two glass substrates are adhered while maintaining a predetermined aperture therebetween using a separator, and the liquid crystals are injected into the aperture, thereby completing the LCD. Subsequently, the present invention will be described in more detail through the detailed embodiments.

SYNTHETIC EXAMPLE: Synthesis of the multifunctional cinnamate compound (pentaerythritol tetracinamate) 100 ml of tetrahydrofuran was mixed with 13.6 g of pentaerythritol and 17 g of cinnamoyl chloride and then 3 g of pyridine were added thereto to react the resulting at room temperature environment for 2 hours and then at 60 ° C for 1 hour. After the reaction, the resultant was cooled and the unreacted ingredients were removed and a pyridine salt as a by-product was removed and then recrystallized, whereby the pentaerythritol tetracinnamate was obtained.

EXAMPLE 1 0.03 g of the pentaerythritol tetracinamate compound produced in the Synthetic Example was dissolved in 10 ml of NMP and then 0.27 g of PVCi (fg by Aldrich Industries, Ltd.) was added, whereby an optical alignment composition was prepared. The composition was coated with rotation on two glass substrates and then the NMP was evaporated and stirred at 100 ° C for about 1 hour, whereby an alignment layer was produced. Subsequently, linear polarized light of 313 nm wavelength was irradiated within the alignment layer to conduct a photoreaction for about 5 minutes. Then, two glass substrates adhered while maintaining a predetermined aperture therebetween using a separator, and liquid crystals (commercially available under the trademark ZLT 22 mtd. By Merck &Co., Ltd.) were injected inside the opening, with which the LCD was completed.

EXAMPLE 2 With the exception that 0.06 g of pentaerythritol tetracinamate and 0.24 g of PVCi were used, an LCD was manufactured in the same manner as described in Example 1.

EXAMPLE 3 With the exception that 0.03 g of pentaerythritol tetracinamate and 0.27 g of PVMC were used, instead of PVCi, an LCD was manufactured in the same manner as described in Example 1.

EXAMPLE 4 With the exception that 0.06 g of pentaerythritol tetracinnamate and 0.24 g of PVMC were used, instead of PVCi, an LCD was manufactured in the same manner as described in Example 1.

EXAMPLE 5 With the exception that 0.03 g of pentaerythritol tetracinamate and 0.27 g of polyimide containing a cinnamate group were used in its side chain, instead of PVCi, an LCD was manufactured in the same manner as described in Example 1.

COMPARATIVE EXAMPLE 1 With the exception that tetracinamate pentaerythritol was not added, an LCD was manufactured in the same manner as described in Example 1.

COMPARATIVE EXAMPLES 2-5 With the exception that 0.09 g and 0.21 g (Comparative Example 2), 0.12 g and 0.18 g (Comparative Example 3), 0.15 g and 0.15 g of (Comparative Example 4), and 0.18 g and 0.12 g (Comparative Example 5) of tetracinamate were used. of pentaerythritol and PVCi, respectively, an LCD was manufactured in the same manner as described in Example 1. Then, with respect to the LCDs manufactured according to the Examples and Comparative Examples, the degree of alignment and the thermal stability were measured of the alignment layer. The degree of alignment was observed by means of a polarization film. The thermal stability was measured by aging while the temperature is increased (up to about 200 ° C), the temperature is lowered to room temperature, and then the degree of deformation of the alignment layer is observed by a polymerization film. As a result, the LCDs manufactured in accordance with the Examples had excellent alignment property and had such excellent thermal stability that the alignment layer barely transformed even when the temperature was raised to 200 ° C. However, the LCD manufactured according to Comparative Example 1 had an excellent alignment property, but had poor thermal stability so that the alignment layer deformed starting at about 80 ° C. In the case of the LCDs manufactured according to Comparative Examples 2 to 5, the thermal stability thereof was somewhat improved, but the alignment property thereof was at an intermediate or lower level. As described above, according to the present invention, an optical alignment composition and an alignment layer each having excellent thermal stability and alignment property can be obtained while adopting an optical, non-destructive alignment method. Therefore, an LCD with improved performance can be obtained.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, property is claimed as contained in the following:

Claims

1. An optical alignment composition, characterized in that it comprises a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8.

2. The optical alignment composition according to claim 1, characterized in that the multifunctional cinnamate compound has two to four cinnamate groups.

3. The optical alignment composition according to claim 2, characterized in that the multifunctional cinnamate compound is a compound selected from the group consisting of alkyldiol dicynamate of 2 to 6 carbon atoms, tricylin of alkyltriol of 2 to 6 carbon atoms and alkyltetraol tetracinamate of 2 to 6 carbon atoms.

4. The optical alignment composition according to claim 1, characterized in that the polymer-containing cinnamate group is selected from the group consisting of poly (inylcinamate) (PVCi), poly (vinylmethoxycin ate) (P and polyimide having a cinnamate group in its side chain.

5. The optical alignment composition according to claim 4, characterized in that the polymer-containing cinnamate group has a weight-average molecular weight in the range of 5,000 to 200,000.

6. An alignment layer characterized in that it comprises a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2.8.

7. The alignment layer according to claim 6, characterized in that the multifunctional cinnamate compound has two to four cinnamate groups.

8. The alignment layer according to claim 7, characterized in that the multifunctional cinnamate compound is a compound selected from the group consisting of alkyldiol dicynamate of 2 to 6 carbon atoms, alkyltriol tricinamate of 2 to 6 carbon atoms and tetracinamate of alkyltetraol of 2 to 6 carbon atoms.

9. The alignment layer according to claim 6, characterized in that the polymer-containing cinnamate group is selected from the group consisting of poly (vinylcinnamate) (PVCi), poly (vinylmethoxycinnamate) (PVCM) and polyimide having a cinnamate group in its side chain.

10. The alignment layer according to claim 9, characterized in that the polymer-containing cinnamate group has a weight-average molecular weight in the range of 5,000 to 200,000.

11. A liquid crystal display (LCD) device, characterized in that it comprises an alignment layer having a multifunctional cinnamate compound and a cinnamate group containing polymer in a weight ratio of 1: 9 to 2: 8.

12. The LCD according to claim 11, characterized in that the multifunctional cinnamate compound has two to four cinnamate groups.

13. The LCD according to claim 12, characterized in that the multifunctional cinnamate compound is a compound selected from the group consisting of alkyldiol dicynamate of 2 to 6 carbon atoms, alkyltriol tricinamate of 2 to 6 carbon atoms and tetratetranyl of tetratetralol from 2 to 6 carbon atoms.

14. The LCD according to claim 11, characterized in that the polymer-containing cinnamate group is selected from the group consisting of poly (vinylcinnamate) (PVCi), poly (vinylmethoxycinnamate) (P and polyimide having a cinnamate group in its side chain.

15. The LCD according to claim 14, characterized in that the polymer-containing cinnamate group has a weight-average molecular weight in the range of 5,000 to 200,000.