KR102008255B1 - Photo-alignment apparatus using pulse uv - Google Patents

Abstract

The present invention relates to a photo-alignment device using pulsed UV, characterized in that the alignment of the liquid crystal by irradiating the pulsed UV to the alignment film, according to an embodiment of the present invention, the chamber, the UV installed above the chamber Provided is an optical alignment apparatus using pulsed UV including a lamp for emitting light, a stage provided on the lower portion of the chamber and a substrate on which an alignment layer is formed, and a polarizer detachably installed between the stage and the lamp. do.

Description

Optical alignment device using pulse shocks {PHOTO-ALIGNMENT APPARATUS USING PULSE ＵＶ}

The present invention relates to an optical alignment device, and more particularly, to an optical alignment device using pulsed UV, characterized in that the alignment of the liquid crystal is carried out by irradiating pulsed UV to the alignment layer.

With the progress of the liquid crystal panel manufacturing technology, liquid crystal display devices are widely used in the field of optical information processing.

In the conventional case, TN (Twisted Nematic) display method is most commonly used as a liquid crystal display device used in small and medium-sized displays. The electrodes are installed on two substrates and the liquid crystal directors are arranged to be twisted 90 degrees, and then It is a technique of driving a liquid crystal director by applying a voltage.

TN type liquid crystal display device provides excellent contrast and color reproducibility, among which vertical alignment (VA) mode in which the long axis of the liquid crystal molecules is arranged perpendicular to the upper and lower display panels without an electric field applied thereto. Liquid crystal display devices are in the spotlight due to their large contrast ratio. However, the TN type liquid crystal display has a problem that the viewing angle is narrow.

In order to solve the viewing angle problem of the TN method, a PVA mode (Patterned Verticlally Aligned Mode) in which a cutout is applied to a liquid crystal display device in a vertical alignment mode, two electrodes are formed on one substrate, and the two electrodes are formed between two electrodes. IPS mode (In-Plane Switching Mode) for controlling the director of the liquid crystal is introduced.

Thereafter, in order to improve the low aperture ratio and transmittance of the IPS mode, the gap between the counter electrode and the pixel electrode is formed to be narrow between the counter electrode and the pixel electrode while the counter electrode and the pixel electrode are formed of a transparent conductor. Fringe field switching mode (FFS) for operating liquid crystal molecules has emerged.

On the other hand, the FIS mode has been developed to solve the problem that the light efficiency of the FFS mode is less than the TN mode, in addition to improving the low transmittance between the pixel electrode in the conventional FFS mode, voltage application method through two thin film transistors As a result, a liquid crystal display device capable of driving a low voltage can be achieved.

In addition, each of these modes has a unique liquid crystal array and optical anisotropy. Therefore, in order to compensate for the phase difference resulting from the optical anisotropy of these liquid crystal modes, the optical retardation film of the optical anisotropy corresponding to each mode is required. The optical retardation film was developed as a color compensation film of LCD, but in recent years, various functions such as high wavelength dispersion, wide viewing angle, temperature compensation, and high phase difference film are required.

In the case of a liquid crystal display device, the orientation of the liquid crystal molecules controlled in advance is changed to another alignment state by applying an electric field, and the polarization direction or polarization state of the transmitted light is changed, and the change is made into a contrast of contrast with a polarizing plate or the like. It is common to change the display.

As a conventional method for orienting the liquid crystal, a contact rubbing method is used in which a polymer film such as polyimide is applied to a substrate such as glass, and the surface is rubbed with a fiber such as nylon or polyester in a constant direction. The liquid crystal alignment by the contact rubbing method as described above has the advantage of obtaining a simple and stable alignment of the liquid crystal, but when the fiber and the polymer film is rubbed, fine dust or electrostatic discharge (ESD) is generated and the substrate is damaged. As the roll is enlarged due to the increase in process time and the enlargement of the glass, it may cause serious problems in manufacturing the liquid crystal panel due to process difficulties such as uneven rubbing strength.

In order to solve the problems of the contact rubbing method as described above, research on the manufacture of a non-contact alignment film of a new method is actively conducted. As a method for producing a non-contact type alignment film, there are a photo alignment method, an energy beam alignment method, a vapor deposition alignment method, and an etching method using lithography.

In particular, the photo-alignment method refers to a mechanism for forming a photopolymerizable liquid crystal alignment film in which a photoreaction material bonded to a photoreactive polymer by linearly polarized UV causes a photoreaction to be uniformly aligned, thereby aligning liquid crystals.

For this purpose, when irradiating linearly polarized ultraviolet rays, the photoreactive material should be arranged in a certain direction and angle according to the polarization direction, and the matching with the reactive liquid crystal is well performed so that the liquid crystal alignment is well performed by interaction with the reactive liquid crystal. Should be done. In particular, the photo-alignment material forming the photo-alignment layer should have good physical properties such as printability, orientation stability, and thermal stability.

As the photoreaction by ultraviolet irradiation, photopolymerization reactions such as cinnamate, coumarin, chalcone, stilbene, diazo, photoisomerization of cis-trans isomerization, and molecular chain cleavage of decomposition are known. There are cases in which the molecular light reaction by ultraviolet rays is applied to the alignment of liquid crystals by ultraviolet irradiation through the design of appropriate alignment layer molecules and optimization of ultraviolet irradiation conditions.

For example, in Republic of Korea Patent Publication No. 10-0423213 (Patent Document 1), the liquid crystal alignment ability is imparted by performing linearly polarized ultraviolet irradiation without performing a rubbing process. The liquid crystal display element which has this liquid crystal aligning film is disclosed. In particular, a number of patents related to the optical alignment method have been filed in Japan, Korea, Europe, the United States, and the like, which are related to the LCD industry. However, since the initial idea was derived, it has been in mass production but has not been widely applied throughout the industry.

This is because it is possible to induce a simple liquid crystal alignment by the optical reaction, but because it does not maintain or provide a stable alignment characteristics in terms of external heat, light, physical shock and chemical impact. That is, the photo-alignment method has lower productivity or reliability than the rubbing method. The main causes of such problems include low alignment energy (anchoring energy), low orientation stability of the liquid crystal compared to the rubbing method.

KR 10-0423213 B1 (2004.03.04 Enrollment)

The present invention has been made to solve the problems described above, by shortening the process time of the photo-alignment agent using the polarized pulse UV, to provide an optical alignment apparatus using a pulse UV that can maximize the productivity and efficiency of the photoreaction The purpose.

In addition, another object of the present invention is to provide an optical alignment device using pulsed UV which has an orientation property and an orientation stability to have an excellent retardation ability.

According to a preferred embodiment of the present invention, a chamber, a lamp installed on the upper part of the chamber and emitting UV light, a stage provided on the lower part of the chamber and the alignment film is formed on the surface, and the stage and the lamp There is provided an optical alignment device using pulsed UV including a polarizer detachably installed therebetween.

Here, the lamp is characterized in that it emits pulsed UV light.

In this case, the lamp may be installed in a housing installed on the upper one side of the chamber.

In addition, the polarizer is replaceably installed on a support installed between the lamp and the stage.

At this time, the support is horizontally installed between the lamp and the stage, the opening is formed in one side opening in the vertical direction, the coupling portion having a slide groove is formed along the edge of the opening to enable insertion of the polarizer do.

In this case, the support may be installed to be elevated in the chamber.

In addition, the stage may be installed to be movable slide, it is also possible to be installed to be adjustable height.

At this time, the pulsed UV light has a 0.1mJ / pulse ~ 500J / pulse energy.

In addition, the pulsed UV light is preferably irradiated at 1Hz ~ 60Hz.

According to a photoalignment apparatus using pulsed UV according to an exemplary embodiment of the present invention, shorten the exposure process time of the photoalignment agent including the reactive liquid crystal using polarized pulsed UV, thereby improving productivity and mass production.

In addition, since polarized pulsed UV is used, it is possible to have an excellent retardation ability by having orientation and orientation stability.

1 is a schematic diagram of an optical alignment device using pulsed UV according to an embodiment of the present invention.
2 is a perspective view of a support according to an embodiment of the present invention.
3 is a schematic diagram illustrating the characteristics of pulsed UV.
Figure 4 is a flow chart of the manufacturing method of the optical retardation film using the optical alignment device according to an embodiment of the present invention.
5 is a flowchart illustrating a manufacturing method of a general liquid crystal display using an optical alignment device according to an embodiment of the present invention.

Hereinafter, a preferred embodiment of the optical alignment device using the pulse UV of the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of the components shown in the drawings may be exaggerated for clarity and convenience of description.

In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to the intention or convention of a user or an operator. Therefore, definitions of these terms should be made based on the contents throughout the specification.

In addition, the following examples are not intended to limit the scope of the present invention but merely illustrative of the components set forth in the claims of the present invention, which are included in the technical spirit throughout the specification of the present invention and constitute the claims Embodiments that include a substitutable component as an equivalent in the element may be included in the scope of the present invention.

Example

1 is a schematic diagram of an optical alignment device using pulsed UV according to an embodiment of the present invention.

As shown in FIG. 1, an optical alignment device (hereinafter, referred to as an “optical alignment device”) 100 using pulsed UV according to an embodiment of the present invention may include a chamber 200 and an upper portion of the chamber 200. The lamp 300 is installed and emits pulsed UV light, and is provided below the chamber 200 and is detachably disposed between the stage 400 on which the substrate 500 is seated and between the stage 400 and the lamp 300. It includes a polarizer 600 is installed.

In this case, the lamp 300 may include a pulsed UV light source and a lens, and is preferably installed in the housing 310 provided above the chamber 200. The lamp 300 may be made of a material having a good UV transmission efficiency, for example, quartz or sapphire, and may be formed into various shapes such as a straight tube, a U-shape, and a spiral. However, in order to uniformly irradiate the pulse UV to the target substrate 500, it is preferable to manufacture the lamp 300 in a form similar to the shape of the substrate 500.

The stage 400 may be installed to be slidably moved in front, rear, left, and right directions. To this end, for example, a guide rail is provided on the bottom surface of the chamber to guide the direction of movement of the stage, and a moving cylinder or a motor for moving the stage may be installed at one side of the chamber. At this time, the cylinder rod end of the moving cylinder is coupled to one side of the stage 400, or one end of the lead screw coupled to the motor shaft is screwed to one side of the stage 400.

In addition, the height of the stage 400 may be adjusted by cylinder or motor operation. In this case, the distance between the substrate 500 and the lamp 300 or the polarizer 600 seated on the stage 400 may be adjusted. This is possible. An alignment film is formed on the surface of the substrate 500. In this case, the alignment layer may include, for example, polyimide, polyvinyl, polysiloxane, polysiloxane, polyacryl, or polyacryl including photoreaction of cinnamate, chalcone, coumarin, stilbene, diazo, and the like. It can be made of a) -based material.

The substrate 500 includes a photomask 510. The photomask 510 is positioned on the alignment layer-coated substrate 500 to allow formation of a multi-domain pattern. In this case, the photomask 510 may be attached to the surface of the substrate 500, or may be spaced apart from the upper portion of the substrate 500.

The method of forming a multi-domain pattern using the photomask 510 may include, for example, forming the first domain using the photomask during the first exposure and exposing the entire surface after removing the photomask during the second exposure. The first exposure may be performed first, followed by partial secondary exposure using a photomask. At this time, since the polarization direction at the time of the primary exposure and the secondary exposure is different, it is necessary to be configured to enable the rotation or movement of the polarizer 600 or the substrate 500 in order to adjust the polarization direction.

The optical alignment device 100 according to the exemplary embodiment of the present invention is supplied with power by a DC power supply (not shown) provided at one side of the chamber 200. The constant energy supply thus supplied is stored in the form of current by the capacitor and accumulates at high energy. The accumulated high energy current is converted into pulses by the pulse generator 320, and the shape, waveform, and wavelength of the pulse are determined according to the type of the pulse generator 320 and the UV lamp 300. High energy in the form of pulses injected by the pulse generator 320 is irradiated to the substrate 500 in the form of pulse UV by the lamp 300.

Meanwhile, the optical alignment device 100 according to the exemplary embodiment of the present invention may further include a band pass filter 800 disposed between the lamp 300 and the polarizer 600. The band pass filter 800 can appropriately adjust the wavelength of the pulse UV irradiated from the lamp 300.

2 is a perspective view of a support according to an embodiment of the present invention.

A cross-bar between the lamp 300 and the stage 400, the support 700 in the form of a cube bar (bar) is installed horizontally in the chamber 200. One side of the support 700 is opened up and down to allow the pulse UV emitted from the lamp 300 to be irradiated to the substrate 500 on the stage 400 through the support 700.

The polarizer 600 is installed in the opening 710 of the bottom of the support 700 to polarize the pulsed UV emitted from the lamp 300. In this case, the opening 710 and the substrate 500 may be formed to have an area corresponding to a region where the energy and intensity uniformity of the pulse UV is 80% or more. In addition, the polarizer 600 is preferably installed to be fixed or detachable to the opening 710 of the support (700). To this end, a coupling part 720 having a slide groove is formed along the edge of the opening 710 of the bottom of the support 700.

The coupling part 720 includes an extension part 721 extending downward along the edge of the opening 710, and a seating part 722 bent inwardly from the lower end of the extension part 721. One side of 721 is open. That is, for example, when the opening 710 is formed in a rectangular cross-sectional shape, one edge of the coupling portion 720 is opened, and the polarizer 600 may be slide-coupled to the coupling portion 720 through the opening portion. .

The support 700 may be installed to be elevated in the chamber 200. For example, a guide rail may be provided on the inner wall of the chamber 200 to guide the lifting direction of the support 700, and the support 700 may be lifted along the guide rail by an operation of a moving cylinder or driving a motor. Can be. At this time, the cylinder rod end of the moving cylinder is coupled to one side of the support 700, or one end of the lead screw coupled to the motor shaft is screwed to one side of the support 700. As such, when the support 700 is installed to be elevated, the gap between the polarizer 600 and the lamp 300 or the polarizer 600 and the substrate 500 can be freely adjusted as necessary.

Meanwhile, the support 700 may be configured to allow the polarizer 600 to be rotated. For example, the entire support 700 may be rotated along the guide groove formed on the inner circumferential surface of the inner wall of the chamber 200 by driving the motor. Can be configured. As another example, the coupling part 720 to which the polarizer 600 is coupled may be manufactured as a separate member, and the coupling part 720 may be configured to rotate on the support 700 by motor driving. In this case, the supporter 700 and the polarizer 600 may be configured to rotate together with the substrate 500 in a fixed state.

The above-described movement or rotation of the stage 400, the support 700, and the coupling unit 720 may be controlled by a controller (not shown) provided outside the chamber 200. By the rotation of the support 700 or the coupling part 720, it is possible to form multi-domains having different orientation directions on the substrate 500.

That is, when the surface of the substrate 500 is divided into a plurality of domains, for example, after the first domain is photo-aligned, the stage 400 is moved so that the second domain is positioned under the polarizer 600 and the polarizer ( By irradiating pulse UV to the second domain after rotating the predetermined angle 600), the liquid crystal alignment directions of the first domain and the second domain may be different from each other.

3 is a schematic diagram illustrating the characteristics of pulsed UV.

In FIG. 3, the x-axis is time t, and the y-axis is peak power having a unit of W (watt). The general UV irradiation method applied to the curing and the like is a method of continuously irradiating ultraviolet rays having a constant energy, in the present invention, UV having a high energy in the form of a pulse (pulse) is irradiated. This pulsed UV is only irradiated for a very short time and cooled for a relatively long time. That is, the duty cycle (the time the pulse is on / the total time the pulse is repeated × 100 (%)) has a very small value of less than 1%, so that the irradiation time is short overall and the cooling time is long, so the pulse There is an advantage that no heat is generated during the UV irradiation process.

According to an embodiment of the present invention, the pulsed UV polarized by the polarizer 600 may output a wavelength of 50 nm to 800 nm. The polarized pulse UV may emit light in the wavelength range of 400 nm to 800 nm as well as light in the ultraviolet range of 50 nm to 400 nm.

Thus, unlike conventional mercury UV lamps, metal halide UV lamps, or gallium UV lamps, each of which emit light only at a particular wavelength in the ultraviolet region, the lamp 300 of the present invention can emit light in a wide wavelength region. Will be.

The polarized pulse UV can be irradiated at 0.1 mJ / pulse to 500 J / pulse with a pulse width of 20 microseconds or less and a pulse of 1 to 60 Hz per second. Thus, for example, if a conventional UV lamp is oriented 12 seconds at 100 mW to orient the photoalignment layer, the lamp 300 of the present invention is, for example, 0.02 due to the strong irradiation energy and intensity of the pulsed UV. Even if it is irradiated for less than a second, it becomes possible to orientate the optical alignment layer of a board | substrate. That is, according to one embodiment of the present invention, there is an effect of shortening the process time by shortening the light irradiation time at the time of optical alignment, thereby improving productivity. In addition, since light is irradiated only for a very short time, it is possible to prevent thermal damage and thermal deformation of the optical alignment layer.

As the light emitting lamp is far from the surface of the object, the difference between the light intensity at the point corresponding to the lamp center and the light intensity at the peripheral portion thereof is more severe. Therefore, UV brightness and uniformity are better as the substrate 500 is closer, but in the conventional case, a minimum irradiation distance has to be maintained due to thermal deformation directly received by the substrate 500. In general, the irradiation distance of about 100 ~ 150mm is secured. In this case, the uniformity of the lamp center and the periphery is about 30%.

However, in the case of the lamp 300 according to the exemplary embodiment of the present invention, as the pulse UV is irradiated, heat generation is almost insignificant and thus does not thermally affect the surface of the substrate 500. Therefore, pulse UV may be irradiated as close to the surface of the substrate 500 as possible (for example, within 5 mm), and uniformity of brightness may be maintained at about 100%.

In addition, since the polarized pulse UV irradiates the optical alignment layer of the substrate 500 with an instantaneous pulse wave in a very short time, it has a strong penetration force during optical alignment. As a result, the polarized pulsed UV can evenly distribute the light even in a thickness layer.

In terms of cost, the polarized pulsed UV can reduce power consumption by 80% or more than when using a conventional arc discharge lamp. Polarized pulsed UV uses instantaneous UV energy, reducing power usage.

In addition, the polarized pulse UV is capable of instantaneous ON / OFF function, the lamp can be turned off when UV irradiation is unnecessary in the process flow, there is an energy saving effect and does not require an opening and closing device such as a shutter. In addition, heat reduction can lead to longer life of the lamp or equipment. In addition, since there is no cost of replacing consumables such as cold mirrors and hot mirrors used in conventional UV lamps, there is an advantage in terms of economy.

4 is a flowchart illustrating a method of manufacturing an optical retardation film using an optical alignment device according to an embodiment of the present invention. Referring to FIG. 4, in order to prepare an optical retardation film, a photo alignment agent is first coated on a substrate and dried. Subsequently, the substrate is irradiated with a polarization pulse UV, in which case an optical alignment device according to an embodiment of the present invention may be used, and a multi-domain forming process may be included. Thereafter, coating and drying of the reactive liquid crystal mixture are performed, and the substrate is irradiated with a non-polarized pulse UV or a general unpolarized UV to finish the substrate.

5 is a flowchart illustrating a method of manufacturing a general liquid crystal display using an optical alignment device according to an embodiment of the present invention. Referring to FIG. 5, a photo alignment agent is first coated and dried on a washed TFT substrate or a CF substrate. Subsequently, the substrate is irradiated with a polarization pulse UV, in which case an optical alignment device according to an embodiment of the present invention may be used, and a multi-domain forming process may be included. Subsequently, the liquid crystal is injected and sealed by an ODF (One-Drop-Filling) method, followed by a cell assembly step including a seal hardening, followed by heat treatment.

100: optical alignment device
200: chamber
300 lamp
310: housing
320: pulse generator
400: stage
500: Substrate
510: photomask
600: polarizer
700: support
800: Band Pass Filter

Claims (10)

chamber;
A lamp installed at an upper portion of the chamber and emitting pulsed UV light;
A stage provided below the chamber and on which a substrate having an alignment layer formed thereon is mounted;
A polarizer detachably installed between the stage and the lamp; And
A supporter installed between the lamp and the stage to move up and down in the chamber, and the polarizer replaceably installed;
Optical alignment device using a pulse UV comprising a.
The method according to claim 1,
And a band pass filter disposed between the lamp and the polarizer.
The method according to claim 1,
The lamp is optical alignment device using a pulse UV, characterized in that installed in the housing installed on the upper side of the chamber.
delete The method according to claim 1,
The support is installed horizontally between the lamp and the stage, the opening is formed in one side opening in the vertical direction, the coupling portion having a slide groove is formed along the edge of the opening to enable insertion of the polarizer. Optical alignment device using a pulse UV characterized in that.
delete The method according to claim 1,
The stage is an optical alignment device using a pulse UV, characterized in that the slide movement is installed.
The method according to claim 1,
The stage is an optical alignment device using a pulse UV, characterized in that the height adjustable.
The method according to claim 1,
The pulse UV light is an optical alignment device using a pulse UV, characterized in that having an energy 0.1mJ / pulse ~ 500J / pulse.
The method according to claim 1,
The pulse UV light is an optical alignment device using a pulse UV, characterized in that irradiated at 1Hz ~ 60Hz.

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