CN1963641A - Manufacturing method of LCD - Google Patents

Abstract

This invention disclosed a method to produce LCD, which include supply baseplate, on the baseplate eliminate high wettability tropism film; and drip liquid crystal isometry onto the tropism film.

Description

Manufacturing method of liquid crystal display

This application is a divisional application of the patent application with the application number 02159866.5 and the invention title "A device for controlling liquid crystal distribution and a method for manufacturing a liquid crystal display" filed on December 27, 2002, and its entire content is hereby incorporated by reference.

technical field

The invention relates to a liquid crystal display (LCD), in particular to a method for controlling distribution of liquid crystals, which can maximize the distribution of liquid crystals in the process of dripping liquid crystals. The invention also relates to a manufacturing method of LCDs.

Background technique

With the development of information socialization, the demand for various forms of displays is increasing. In recent years, in order to meet these requirements, various flat display panels have been developed, such as liquid crystal displays (LCDs), plasma display panels (Plasma Display Panels, PDPs) ), Electro Luminescent Display (ELD), Vacuum Fluorescent Display (Vacuum Fluorescent Display, VFD), etc., some of which have been used as displays in various devices.

Among various flat-panel displays, LCD has been widely used as a portable display. At the same time, LCD has replaced the cathode ray tube (Cathode Ray Tube, CRT) due to its excellent picture performance, light weight, thin size and low energy consumption. In addition to portable LCDs such as laptop monitors, LCDs are making their way to televisions and computer monitors that receive and display broadcast signals.

An LCD has two opposing substrates between which liquid crystals are injected, which change state with temperature and density.

Liquid crystal is a substance with intermediate properties between liquid and solid, and it has the fluidity of liquid and the regularity of solid in a wide range. That is, a liquid crystal is an intermediate state between a crystalline solid and a liquid before the crystalline solid melts into a liquid. Once light, or electricity, or a magnetic field is added to the liquid crystal, it will show the birefringence (birefringence) unique to the optical anisotropic crystal. In a certain temperature range, liquid and properties of crystalline solids.

The aforementioned LCD can be manufactured by performing arraying, unitizing, and modularizing processes on a glass substrate.

In the arraying process, wiring patterns or switching devices such as thin film transistors (in the case of an active matrix type) can be produced. In the unitization process, alignment treatment, isolation treatment, or injection of liquid crystal into an opposite glass substrate is performed, followed by sealing. In modular processing, driver integrated circuits (ICs) and backlights are installed.

The liquid crystal injection method in the unitization process will be briefly described below.

Firstly, a large board is provided, which is manufactured by combining and fixing together a substrate area including a plurality of TFT units and a substrate area including a plurality of color filter units by means of a sealant.

The TFT unit substrate area is provided with a plurality of grid lines extending in a certain direction at fixed intervals, a plurality of data lines extending in a direction perpendicular to the grid lines at fixed intervals, and on the pixel area matrix defined by the grid lines and data lines A plurality of thin film transistors and pixel electrodes are arranged, and they are respectively formed during array processing.

The substrate area of the color filter unit is provided with a black matrix layer for protecting parts other than the pixel area, the color filter layer and the common electrode.

Cut the large board into multiple LCD cell boards. Then, the liquid crystal and the plurality of LCD unit panels are placed in a vacuum chamber, and the injection hole formed by the sealant is dipped into the liquid crystal. Then, the liquid crystal is injected into the center of the LCD cell panel by returning the vacuum chamber to the atmospheric pressure state. This liquid crystal injection method is called a vacuum injection method and will be described in more detail later.

Referring to FIG. 1 , a container 30 is filled with liquid crystals, and they are placed in a chamber 20 . A degassing process is then performed in which the chamber 20 is maintained in a vacuum state capable of removing moisture in the liquid crystal or moisture adhering to the inner wall of the chamber and small air bubbles in the liquid crystal.

Next, after the liquid crystal is injected into the liquid crystal injection hole of the LCD cell panel 40 or brought into contact with the liquid crystal, nitrogen gas N ₂ is introduced into the chamber 20 to change the pressure of the chamber from vacuum to atmospheric pressure. Then, the liquid crystal is injected into the LCD unit panel through the injection hole by utilizing the pressure difference between the inner wall pressure of the LCD unit panel 40 and the chamber pressure.

When the liquid crystal 25 fills the LCD cell panel 40, the LCD cell panel is cleaned after the injection hole is sealed.

Since liquid crystal injection takes a long time due to cutting the LCD unit panel, maintaining the space between the two substrates in a vacuum state, dripping the LCD unit panel into the liquid crystal, or bringing the LCD unit panel into contact with the liquid crystal, the aforementioned liquid crystal injection method productivity is low. In addition, when a large LCD is manufactured, since the liquid crystal is not completely injected into the LCD cell panel, this causes a defective LCD.

Recently, in order to solve the aforementioned problems, the following liquid crystal dropping method (dropping method) was finally born. Next, a method of manufacturing an LCD using a liquid crystal dropping method will be described with reference to the drawings.

Referring to FIG. 2, an alignment material is coated on a first substrate having a TFT unit substrate region and a second substrate having a color filter unit substrate region. Then, an alignment treatment process is performed such that the liquid crystal molecules have directionality (1S), and the first and second substrates are cleaned (2S).

Load the cleaned second substrate onto the sealant dispenser and apply sealant to the periphery of each plate area (3S). Photocurable and thermosetting resins can be used as the sealant without the need for liquid crystal injection holes.

On the other hand, the first substrate is loaded on a liquid crystal (LC) dispenser, and the liquid crystal is dripped into the active array area of each panel (6S). In this case, the cleaned first and second substrates can be loaded onto a silver (Ag) dispenser to form Ag dots on the common voltage delivery line of the first substrate, or in In Plane Switching (IPS) mode Next, the formation of Ag dots can be omitted.

The liquid crystal dropping method will now be briefly described.

Referring to FIG. 3 , the first substrate 60 is loaded onto the stage 70 of the liquid crystal dispenser 50 . Above the first substrate 60 is a syringe 80 filled with liquid crystals for dripping liquid crystals.

In general, the liquid crystal 65 is dripped onto the substrate 60 in the form of droplets. The substrate 60 moves at a constant speed and direction while the ejector 80 discharges a matching liquid crystal 65 thereto, thus setting the liquid crystal drop position.

Although not shown in the drawings, the ejector 80 has an external gas passage connected thereto for supplying nitrogen gas _N2 from an external gas source so as to pressurize the liquid crystal to drop the liquid crystal.

Referring to the figure below, the first and second substrates are loaded into the vacuum combining chamber for bonding, so that the dripped liquid crystal is evenly filled into the board, and the sealant (7S) is set, thus completing the manufacture of the large board.

Then, carry out scribing/cracking Scribe/Break (S/B) process (9S), this processing comprises scribing process and cracking process, in said scribing process, utilizes the diamond pen with hardness higher than glass hardness Cutting lines are formed on the surface of the glass. During the cracking process, a certain force is applied to the glass to break the glass, thereby cutting the large plate into multiple LCD unit panels for liquid crystal cells.

Then, after the surface of the LCD unit panel is polished (10S), an Auto/Probe (A/P) inspection is performed on the LCD unit panel (11S), thereby completing the liquid crystal cell process.

In the A/P inspection process, the electrical defect of the LCD unit board is inspected by using a device with voltage terminals that can apply a voltage, that is, the voltage terminals are electrically connected with the gate lines and data lines on the TFT substrate in the LCD unit board, using To detect cell gap defects or defective liquid crystal injection (bad injection, or leakage) in the cell panel.

Although not shown in the drawings, once the liquid crystal cell manufacturing process is completed through the aforementioned series of manufacturing procedures, the module manufacturing process starts, in which a driver IC or a background light source is mounted.

However, the LCD manufacturing method of the liquid crystal dropping method used in the above-mentioned prior art has the following problems.

During the bonding process, the first and second substrates are aligned opposite each other, and the environment is vented until the liquid crystal is dispensed on the substrate surfaces to the encapsulant portion at the periphery, thereby bonding the two substrates.

Specifically, referring to FIG. 4 , the liquid crystal is dropped onto the first substrate 60 in the form of liquid droplets at fixed intervals. The distance between adjacent liquid crystal drops 65 has the following relationship:

dZ=d4=d6=ds>d1=d3=d5=d7.

Next, referring to FIG. 5, in the process of bonding the first and second substrates together, the dropped liquid crystal 65 is always slowly distributed in a circular form 65A on the surface of the substrates. A gap 67 that has not been filled with liquid crystal is formed before the liquid crystal bends and spreads. Therefore, when bonding the first and second substrates, the environment is continuously vented until the gap 67 becomes sufficiently small.

However, it takes 20 minutes until the gap 67 becomes small enough to sufficiently complete the liquid crystal dispensing. There is a risk that the sealant will peel off, and liquid crystal leakage will occur due to a pressure difference between the inner side and the outer side of the substrate during this waiting process.

Although not shown, smudges may occur at the boundaries where the liquid crystal is dropped, which will degrade the picture quality.

Contents of the invention

Accordingly, the present invention is directed to an apparatus for controlling the distribution of liquid crystals and a method of manufacturing an LCD that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

The advantage of the present invention is to provide a device for controlling distribution and a manufacturing method of LCD, which can effectively narrow the liquid crystal gap.

Additional advantages of the invention will be set forth in the description which follows, in part will be apparent from the description and in part will be learned by practice. The objectives and other advantages of the invention may be realized or attained by the structure pointed out in the detailed written description and claims hereof as well as the appended drawings.

As described in the embodiments, in order to achieve these and other advantages of the present invention, according to the purpose of the present invention, a method for manufacturing an LCD is provided, which includes: (a) providing a substrate; (b) forming an LCD on the substrate an alignment film with high moisture absorption; and (c) dripping liquid crystals on the alignment film at fixed intervals.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

The accompanying drawings, to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the description serve to explain the principle of the invention:

Description of drawings

In the attached picture:

1 is a perspective view for explaining a vacuum injection method in the prior art;

Fig. 2 is a flowchart for explaining the drip injection method in the prior art;

3 is a perspective view for explaining the liquid crystal dripping method in the prior art;

Fig. 4 is the state after liquid crystal instillation in the prior art;

Fig. 5 is the state after the bonding process in the prior art;

6 is a flow chart for explaining an LCD manufacturing method to which a drip injection method according to an embodiment of the present invention is applied;

7 is a perspective view for explaining a liquid crystal dropping method according to an embodiment of the present invention;

Fig. 8 is the state after liquid crystal dripping; And

FIG. 9 is a state after liquid crystal dripping according to another embodiment of the present invention.

Detailed ways

Reference will now be made in detail to embodiments of the invention, examples of which are illustrated in the accompanying drawings.

FIG. 6 shows a flowchart for explaining an LCD manufacturing method to which a drip injection method according to an embodiment of the present invention is applied. Fig. 7 shows a perspective view for explaining a liquid crystal dropping method according to an embodiment of the present invention. Fig. 8 shows the state after the liquid crystal is dropped.

Although not shown, the present invention provides first and second substrates that have undergone an arraying process and a color filter process. The first and second substrates respectively include a plurality of thin film transistor (TFT) unit substrate regions and color filter unit substrate regions. After the arraying process and the color filter process are completed, the first substrate and the second substrate are respectively loaded on the In the first box and the second box.

The first case and the second case are loaded onto the loader of the liquid crystal unit production line using the conveyor. The TFT unit substrate area includes a plurality of gate lines extending in a certain direction at fixed intervals, a plurality of data lines extending in a direction perpendicular to the gate lines at fixed intervals, and a plurality of pixel areas defined by the gate lines and the data lines. Thin film transistors and pixel electrodes are formed on the matrix.

The color filter unit substrate includes a black matrix layer for protecting components other than the pixel area, the three primary color filter layers, and the common electrodes for driving liquid crystals, together with the pixel electrodes and the like.

The manufacturing process of the liquid crystal cell under the above conditions is explained below.

Referring to Fig. 6, the first substrate loaded on the first box and the second substrate matched with the first substrate loaded on the second box are selected by using the robot arm, and they are loaded on the orientation processing line, wherein the robot arm Information (not shown) of the first and second boxes installed in the loader can be understood.

In order to remove foreign substances and particles from the first and second substrates, the alignment process is carried out in the order of cleaning (20S) before coating the alignment film: coating the alignment film (21S), baking the alignment film (22S), checking (23S ), and friction (24S), they are briefly described below.

The orientation liquid for coating the orientation film (21S) was dripped between the gumming roll and the anilox roll rotating in the dispenser. The orientation liquid adheres to and remains on the surface of the anilox roll called a liquid film, which is then transferred to the print roll to which the rubber sheet is attached. Then, when the first and second substrates fixed on the coating table are advanced, the alignment liquid film is transferred and coated on the first and second substrates.

Next, in order to evaporate the solvent in the alignment films printed on the first and second substrates, a baking process (22S) is performed, the alignment films are inspected (23S), and then rubbed (24S), thereby completing the alignment process.

After the orientation process is completed, the gap process is performed in the following manner.

After cleaning (25S) the first and second substrates that have completed the orientation process, the first substrate is loaded on the liquid dispenser, the second substrate is loaded on the silver (Ag) dispenser followed by the encapsulant dispenser superior.

At this time, Ag dots are coated on the second substrate for electrical connection with the common electrode (27S), and a sealant without liquid crystal injection holes is coated on the periphery of each cell plate area (28S). The sealant is light, curable resin or thermosetting resin.

On the other hand, liquid crystal is dropped onto the TFT unit substrate area of the first substrate (26S), which is opposite to the inner area of the sealant in the color filter unit substrate on the second substrate, which will be described below.

Referring to FIG. 7 , as the substrate 100 is loaded onto the platform 700 of the liquid crystal dispenser 500 , the liquid crystal injector 800 is disposed above the platform 700 , and the liquid crystal 110 is dripped onto the substrate 100 through the syringe 800 .

Platform 700 has an adjustable temperature control fabrication 700a to control the dispensing of liquid crystals. The adjustable temperature control device 700a preferably consists of a heating wire, which is heated through an electrical connection to control the surface temperature of the platform 700 .

The liquid crystal 110 is dripped onto the substrate 100 in the form of liquid droplets. In this case, the adjustable temperature control device 700a is controlled in such a way that the surface temperature of the platform 700 is controlled in the range of about 30°C to 120°C to ensure the minimum distance between adjacent liquid crystal droplets, which will be described in detail later.

Referring to FIGS. 7 and 8 , liquid crystals are dropped onto the substrate 100 on the platform 700 at a fixed pitch. The adjustable temperature control device 700a on the control platform 700 makes its temperature change, so that the distance between adjacent liquid crystal drops 110 has the following relationship: d2=d4=d6=d8>d1=d3=d5=d7, and minimize the distance. D1=d3=d5=d7 can be zero, which is the effect of suppressing stains at the boundaries of liquid crystal droplets in the prior art.

That is, when high-viscosity liquid crystals are dropped from the injector 800 onto the substrate 100 on the platform 700, the liquid crystal drops are distributed in a circular form due to the surface temperature.

Although not shown, a needle is inserted in the injector, one end of which is in contact with the contact portion of the needle plate, wherein when a spring on the needle contacts the needle with the needle plate, discharge of liquid crystal is prevented.

Next, there is a solenoid coil assembly at the top of the needle. If power is supplied to the helical coil, it can generate electromagnetic energy which will move the needle upwards. Nitrogen gas N ₂ is supplied from an external air source, which can pressurize the liquid crystal to make the liquid crystal drop.

Then, when the power supply to the coil is stopped, the needle returns to the original position due to the elastic force of the spring. The up and down movement of the needle discharges the liquid crystal.

Then, referring to FIG. 6, when the first and second substrates are combined (30S), the dropped liquid crystals are distributed on the substrates in a circular form. In this case, since there is no alkalinity between the liquid crystals, which has been sufficiently reduced during the liquid crystal dropping process, the time required for exhausting ambient gas and bonding the substrates will be greatly reduced.

The bonding process was performed as follows.

Although not shown, the first substrate is mounted on a stage movable in a horizontal direction within the vacuum chamber, and the entire bottom surface of the second substrate is vacuum-adsorbed by the first adsorber. Then, the entire bottom surface of the second substrate is adsorbed by the second adsorber, the vacuum chamber is closed, and exhaust gas is started. Let the second absorber move down vertically until there is a predetermined gap between the first and second, and move the workbench on which the first substrate is installed horizontally until the first and second substrates are aligned.

Then, the second absorber is moved downward in the vertical direction so that the second substrate and the first substrate are bonded together with a sealant, and pressure is applied to the first and second substrates so that the dripped liquid crystal is filled to the desired level. thickness, thus forming a large plate.

The large board is taken out from the vacuum chamber, and the sealant is irradiated with ultraviolet light (UV) to cure the sealant (31S), thus completing the gap process. In this case, a liquid crystal dispensing process may be performed before unloading the bonded substrates so that the liquid crystal supersealant in the bonded substrates is dispensed. The liquid crystal dispensing process takes about more than 10 minutes under atmospheric pressure or vacuum state.

Next, as the gap process ends, the TFT substrate and the color filter substrate are glued together, and they are loaded onto the line for an inspection process.

The inspection process includes: a scribing process, which uses a diamond pen with a hardness higher than that of glass to form a cutting line on the glass surface; breaking the glass, which is used to cut the vacuum-bonded substrate into multiple liquid crystal cell panels; and The surface of the liquid crystal cell panel is polished, and each panel is inspected, thereby completing the manufacturing process of the liquid crystal cell.

Inspections include: visual inspection to check the alignment status of liquid crystals, Anto/Probe (A/P) inspection to check defective blots and electrical switch status. Defective blots can be detected automatically with the naked eye or with a solid-state imaging device such as a charge-coupled device (CCD).

Once the liquid crystal cell manufacturing process is completed through the aforementioned process sequence, a module process of installing a driver IC or installing a backlight source, etc. may be performed.

Although the distance between the liquid crystal drops on the substrate is controlled by controlling the surface temperature of the platform of the adjustable temperature control device in the foregoing embodiments, it is also possible to control the performance of the alignment film formed on the platform during the alignment process to maximize Minimize the distance between liquid crystal drops.

That is to say, referring to FIG. 9, as the alignment film 120 coated in the alignment step in FIG. Good distribution is achieved on the surface of the alignment film 120, with the result that the contact angle θ between the liquid crystal 110 and the alignment film 120 is smaller.

The contact angle θ is the angle formed when a liquid is in thermal equilibrium on a solid surface. In this case, due to the high wettability and good hydrophilicity of the alignment film, the liquid crystal drop 110 tends to contact the thin film of the alignment film 120 , so the contact angle θ is small, and the liquid crystal drop is in contact with it.

Therefore, by minimizing the surface energy between the liquid crystal droplet 110 and the alignment film 120,

The distance between adjacent liquid crystal drops 110 can be minimized, which is enough to make the gap where the liquid crystal does not exist very small. That is to say, the alignment film can form an alignment film with high wettability, thereby providing the effect of inhibiting the stains at the boundaries of liquid crystal droplets in the prior art, which provides the distance relationship between adjacent liquid crystal droplets 110: d2=d4=d6=d8>d1=d3=d5=d7 while minimizing this distance. D1=d3=dS=d7 may be zero.

As already explained, the device for controlling liquid crystal distribution and the LCD manufacturing method of the present invention have the following advantages:

First, the distance between adjacent liquid crystal droplets can be minimized by adopting a platform with heating wires that can change the surface temperature, or by forming an alignment film with good wettability and hydrophilicity on the substrate, which will As a result, the gap in which no liquid crystal exists can be made sufficiently small.

Second, shortening the time required to press and bond the two substrates by evacuating the environment to eliminate the gap can avoid the pressure difference between the inside and outside of the two substrates while waiting to bond the two substrates. The peeling of the sealant and the leakage of the liquid crystal caused by it.

Third, a platform with heating wires or an alignment film with good wettability and hydrophilicity facilitates the distribution of viscous liquid crystals dripping onto the substrate and can shorten the processing time.

Fourth, suppressing the occurrence of blots at the boundaries of liquid crystal droplets can improve picture quality. It will be apparent to those skilled in the art that various modifications and changes can be made in the liquid crystal distribution control device and LCD manufacturing method of the present invention without departing from the spirit or scope of the present invention. Thus, it is intended that the present invention cover the modifications and variations of this invention if they come within the scope of the appended claims and their equivalents.

Claims (13)

1, a kind of manufacture method of LCD, it comprises:

Substrate is provided;

On substrate, eliminate the oriented film of high wettability; And

With constant spacing with liquid crystal drip-injection to oriented film.

2, method according to claim 1, wherein oriented film has very high surface energy, is reduced to minimum in order to the distance between adjacent lcd is dripped.

3, method according to claim 1, it further is included in and forms oriented film clean substrate before.

4, method according to claim 1, it bakes oriented film before further being included in dispenser method.

5, method according to claim 4, it further comprises the inspection oriented film.

6, method according to claim 5, it further comprises oriented film is rubbed.

7, method according to claim 1 wherein is loaded into substrate on the liquid crystal dispensing apparatus, then another piece substrate is loaded on the silver-colored divider, and then is loaded on the coating apparatus for sealant.

8, method according to claim 7, it further is included on the substrate in this substrate and another substrate and applies sealant.

9, method according to claim 8, wherein sealant uses a kind of smooth solidity, thermoset resin.

10, method according to claim 1, it further comprises the control temperature so that the control liquid crystal distributes.

11, method according to claim 10 wherein is controlled at temperature in about 30 ℃-120 ℃ scope.

12, method according to claim 11 is wherein controlled temperature and is dwindled the distance of adjacent lcd between dripping to greatest extent.

13, method according to claim 8, it further comprises in conjunction with substrate and another substrate.

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