Method of Applying Particles

Abstract

The present application relates to a method of applying particles, an optical film and a method of manufacturing an active liquid crystal device. In the method of applying particles of the present application, the particles can be uniformly applied on a base material and fixed while maintaining the shape of particles. The optical film of the present invention produced by the above method can have excellent particle dispersity. A method of manufacturing an active liquid crystal device using the above method can maintain a cell gap uniformly while simplifying the manufacturing process and preventing gravity defects.

Claims

1. A method of applying particles comprising a process of coating a coating composition comprising microparticles, a curable resin and a solvent on a base material having a surface roughness (Ra) of from 3 nm to 100 nm, followed by drying and curing.

2. The method of applying particles according to claim 1, wherein said base material having a surface roughness (Ra) of 3 nm to 100 nm is produced by any one of the following processes a) to d): a) coating a composition comprising nanoparticles, a curable resin and a solvent on a base material, followed by drying and curing; b) forming a base material with a mold; c) eroding a flat base material with a partially erodible solvent; and d) applying physical force to a flat base material.

3. The method of applying particles according to claim 2, wherein said base material comprise one base material film selected from the group consisting of polyethylene terephthalate, polytetrafluoroethylene, polyethylene, polypropylene, polybutene, polybutadiene, vinyl chloride copolymer, polyurethane, ethylene-vinyl acetate, ethylene-propylene copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer and polyimide.

4. The method of applying particles according to claim 3, wherein said base material further comprises a conductive layer formed on said base material film, and said base material is produced by adjusting the surface roughness of said base material film to 3 nm to 100 nm by any one of said processes a) to d) and then forming the conductive layer on said base material film.

5. The method of applying particles according to claim 1, wherein said microparticles are dispersed in a state fixed on said base material.

6. The method of applying particles according to claim 1, wherein said microparticles have a particle diameter of 1 m to less than 100 m.

7. The method of applying particles according to claim 1, wherein said microparticles have a density of 0.61 g/cm.sup.3 to 2.1 g/cm.sup.3, and the density of said microparticles is greater than the density of the solvent.

8. The method of applying particles according to claim 1, wherein said solvent comprises one or more solvents selected from the group consisting of aliphatics including normal hexane, heptane and octane; aromatics including benzene, toluene and xylene; chlorides including dichloromethane, trichloromethane and tetrachloromethane; alcohols including ethanol, isopropanol and butanol; esters including ethyl acetate, propyl acetate and propylene glycol methyl ether acetate (PGMEA); ketones including methyl ethyl ketone (MEK), methyl iso-butyl ketone (MIBK), cyclohexanone and cyclopentanone; and ethers including tetrahydrofuran, petroleum ether, 1,2-dimethoxy ethane (DME) and diethylene glycol dimethyl ether (diglyme).

9. The method of applying particles according to claim 1, wherein said coating composition has a coating thickness of 10 nm to 1000 nm.

10. The method of applying particles according to claim 1, wherein said coating composition comprises the microparticles in an amount of 0.1 to 10 parts by weight, relative to 100 parts by weight of the solvent.

11. An optical film comprising a base material having a surface roughness (Ra) of 3 nm to 100 nm; and microparticles dispersed on said base material, wherein said microparticles have a dispersity of 0.5 to 2.

12. The optical film according to claim 11, wherein said microparticles are fixed on said base material and present in a dispersed state.

13. A method of manufacturing an active liquid crystal device comprising processes of coating a coating composition comprising microparticles, a photo-alignment resin and a solvent on a lower base material having a surface roughness (Ra) of 3 nm to 100 nm, followed by drying and curing, to form a photo-alignment film, and forming a liquid crystal layer on said photo-alignment film.

14. The method of manufacturing an active liquid crystal device according to claim 13, further comprising a process of laminating an upper base material on said liquid crystal layer, wherein said microparticles function as spacers maintaining a gap between said lower base material and said upper base material.

15. The method of manufacturing an active liquid crystal device according to claim 14, wherein said lower base material or said upper base material comprises a base material film and an electrode layer on said base material film.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0059] FIG. 1 is a diagram illustratively shown for explaining a method of applying particles on a base material.

[0060] FIG. 2 is a diagram illustratively showing a base material having an artificially formed surface roughness according to one embodiment.

[0061] FIG. 3 shows AFM images of the base materials produced in Examples 1 to 5.

[0062] FIG. 4 shows AFM images of the base materials produced in Comparative Examples 1 and 2.

[0063] FIG. 5 shows optical microscope images of the base materials produced in Examples 1 to 5.

[0064] FIG. 6 shows optical microscope images of the base materials produced in Comparative Examples 1 and 2.

[0065] FIG. 7 shows graphs of roughness and microparticle dispersity in the base materials produced in Examples 1 to 5 and Comparative Examples 1 and 2.

DETAILED DESCRIPTION OF THE INVENTION

[0066] Hereinafter, the present application will be described in more detail by way of examples according to the present application and comparative examples not complying with the present application, but the scope of the present application is not limited by the following examples.

[0067] Hereinafter, physical properties in Examples and Comparative Examples were evaluated in the following manner.

[0068] 1. Roughness Measurement

[0069] For a base material prior to coating of a ball spacer composition, the surface roughness (Ra) value in an area of 10 m10 m was measured using an AFM (NX10, Park systems) equipment.

[0070] 2. Dispersity Evaluation

[0071] For the base material fixed with ball spacers, the number of ball spacers in a reference area (1 mm.sup.2) was measured using an optical microscope (BX51, OLYMPUS Co., Ltd.) at 40 magnification, and then a value obtained by dividing the number of ball spacers that are not agglomerated by the total number of ball spacers was evaluated as the dispersity.

Example 1

[0072] Production of Base Material

[0073] Polymethylmethacrylate (PMMA) particles (XX-52BQ, SEKISUI) having a particle diameter of 370 nm and an alignment film (5-norbornene-2-methyl-(4-methoxycinnamate)) from the present applicant were mixed in a solvent of cyclohexanone (cyclohexanone 99%, DAEJUNG Chemicals & Metals Co., Ltd.) to prepare a nanoparticle composition (a weight ratio of solvent:PMMA particles:alignment film from the present applicant=100:0.1:4). The nanoparticle composition was coated on a polyethylene terephthalate (PET, COSMOSHINE A4300 125 m, TOYOBO) base material film (widthlength=100 mm100 mm) using a mayer bar (#4) to a thickness of about 10 m. The coated composition was dried in an oven at about 80 C. for about 2 minutes. The dried composition was irradiated with ultraviolet rays having an intensity of about 200 mW/cm.sup.2 for 10 seconds to cure the base material.

[0074] Application of Ball Spacers

[0075] Ball spacers (KBN-512, SEKISUI) having a density of 1.19 g/cm.sup.3 and a particle diameter of 12 m and an alignment film (5-norbornene-2-methyl-(4-methoxycinnamate)) from the present applicant were added to a solvent of cyclohexanone (cyclohexanone 99%, DAEJUNG Chemicals & Metals Co., Ltd.) having a density of 0.948 g/cm.sup.3, followed by mixing, to prepare a ball spacer composition (a weight ratio of solvent:ball spacer:alignment film from the present applicant=100:1:2). The ball spacer composition was coated on the base material as produced above using a mayer bar (#10) to a thickness of about 25 m. The coated composition was dried in an oven at about 100 C. for about 2 minutes. The dried composition was irradiated with ultraviolet rays having an intensity of about 200 mW/cm.sup.2 for 10 seconds and cured to apply the ball spacers on the base material. The ball spacers were fixed on the base material and applied in a dispersed state.

Example 2

[0076] The ball spacers were coated in the same manner as in Example 1, except that the base material film was changed to polyethylene terephthalate (PET, TH46H, SKC, lengthwidth=100 mm100 mm).

Example 3

[0077] The ball spacers were coated in the same manner as in Example 1, except that the base material film was changed to polyethylene terephthalate (PET, U48, Toray, lengthwidth=100 mm100 mm).

Example 4

[0078] The ball spacers were coated in the same manner as in Example 1, except that the ball spacer composition was directly coated on a polyethylene terephthalate (PET, COSMOSHINE A4300, TOYOBO) base material film, and dried and cured.

Example 5

[0079] The ball spacers were coated in the same manner as in Example 3, except that the spacer composition was directly coated on a polyethylene terephthalate (PET, U48, Toray) base material film, dried and cured.

Comparative Example 1

[0080] The ball spacers were coated in the same manner as in Example 1, except that polymethylmethacrylate (PMMA) particles were not mixed at the time of manufacturing the base material.

Comparative Example 2

[0081] The ball spacers were coated in the same manner as in Example 2, except that the ball spacer composition was directly coated on the polyethylene terephthalate (PET, TH46H, SKC) base material film, and dried and cured.

TABLE-US-00001 TABLE 1 Comparative Example Example Classification 1 2 3 4 5 1 2 Roughness (nm) 15.8 15.9 16.0 5.0 5.4 0.8 1.3 Dispersity 0.78 0.81 0.72 0.32 0.45 0.004 0.04

[0082] As shown in Table 1 and FIGS. 3 to 7, it can be confirmed that the ball spacers in Examples 1 to 5 using the base material satisfying the surface roughness of the present application have excellent dispersity, as compared with Comparative Examples 1 and 2 using the base material not satisfying the surface roughness of the present application.

EXPLANATION OF REFERENCE NUMERALS

[0083] 100: base material [0084] 110: base material film [0085] 120: coating layer [0086] 121: nanoparticles [0087] 122: photo-curable resin [0088] 200: coating composition