JP2004177542A - Method and device for manufacturing liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and device for manufacturing an inexpensive liquid crystal display element with high image quality and high productivity. <P>SOLUTION: The method for manufacturing includes a sealing adhesive applying step to form a frame of a sealing adhesive 13 on a periphery of an pixel electrode 11 formed on a substrate by application and a dropping step to drop liquid droplets 12a of a liquid crystal 12 inside the frame while removing electrostatic charge in a space electrically shielded from the outside. Also, the device 51 for manufacturing is provided with a sealing adhesive applying means 53 to form the frame of the sealing adhesive 13 on the periphery of the pixel electrode 11 by application, a dropping means 54 to drop the liquid droplets 12a of the liquid crystal 12 inside the frame, an electrically shielding means 55 to surround the substrate 8 with the pixel electrode formed thereon and the dropping means 54 and to electrically shield the inside from the outside and an electrostatic charge removing means 18 to remove the electrostatic charge from the space inside the electrically shielding means 55 including the liquid droplets 12a. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a liquid crystal display element, and more particularly to a method and an apparatus for manufacturing a liquid crystal display element having a step of attaching a substrate after dropping liquid crystal on a display area.
[0002]
[Prior art]
FIG. 6 shows a general structure of a reflective liquid crystal display element, which is called LCOS (Liquid Crystal on Silicon) and is attracting attention for its high resolution and high luminance, which is obtained by bonding a silicon IC substrate and a glass substrate.
FIG. 6A is an assembled view, and FIG. 6B is a cross-sectional view at a position corresponding to a BB cross section in FIG. 6A after the assembly.
[0003]
The reflection type liquid crystal display element 100 includes a silicon IC having a glass substrate 102 formed on each of opposing surfaces of an antireflection film 108 and a transparent electrode film 101 and a pixel electrode (hereinafter referred to as a display area) 103 on one surface. The substrate 104 is disposed opposite to the substrate 104, and the substrates 102 and 104 are fixed to each other with a seal adhesive 107 applied in a frame shape surrounding the display area 103, and a liquid crystal 105 is supplied from a liquid crystal injection port 109 to a cell gap in the frame. It is configured to be injected and sealed.
The seal adhesive 107 is made of a spacer ball and an adhesive for keeping the gap (cell gap) between both substrates constant.
[0004]
The main application of the reflective liquid crystal display device (LCOS) is for small data projectors and rear projection televisions, which are fiercely cost-competitive. Therefore, the market is required to greatly reduce the cost of this device as well. I have.
In a general manufacturing method of a liquid crystal display element, a liquid crystal injection step and an injection port sealing step are performed in a vacuum after bonding two glass substrates with a sealing adhesive. This requires a total of 10 hours or more of manufacturing time, and the size of the apparatus is increased.
[0005]
On the other hand, in a reflective liquid crystal display element (LCOS), the panel size of the element is generally a relatively small size of 0.5 inches to 0.9 inches.
The cell gap is a narrow gap of 1 μm to 3 μm in order to increase the response speed of the liquid crystal. Therefore, there is a problem that the liquid crystal filling port has a layout close to the effective pixel area, and a defect due to the sealing process is easily generated in the pixel area.
[0006]
Therefore, in order to reduce costs and to avoid defects caused by the sealing process, a sealing adhesive is applied in a frame shape to one of the two glass substrates in advance, and the liquid crystal is placed in the frame. A so-called liquid crystal dropping method has been proposed in which both glass substrates are pressed together and then bonded together (see Non-Patent Document 1).
[0007]
That is, when bonding a glass substrate having a transparent electrode and a color filter to a TFT array substrate, first, an alignment film is formed on each substrate, and the thickness of the liquid crystal layer of the element (cell) is formed on one substrate. A spacer ball that determines the gap) is sprayed, and a seal adhesive is applied on the other substrate in a frame shape without providing a sealing opening around the effective pixel area by a press to bond the two substrates together later. deep.
Next, an appropriate amount of liquid crystal is dropped in a range surrounded by the seal adhesive.
Thereafter, the two substrates are pressed until the sealing adhesive comes into contact with the substrates, and the sealing adhesive is cured by irradiating UV light or the like, thereby fixing the two substrates at a predetermined cell gap.
According to this method, a liquid crystal display element having a desired size can be obtained without performing a liquid crystal injection step and a liquid crystal sealing step.
[0008]
On the other hand, Patent Document 1 describes a method for shortening the time required for dropping liquid crystal.
In this method, the liquid crystal droplets to be dropped are forcibly charged, and the droplets adhere to the substrate by electrostatic force so as to be attracted to the substrate, so that the time required for the dropping can be reduced.
[0009]
[Patent Document 1]
JP-A-3-39929 [Non-Patent Document 1]
"SID (Society for Information Display) 01 DIGEST", (USA), 2001, p. 1350-1353
[0010]
[Problems to be solved by the invention]
In the meantime, the above-described liquid crystal dropping method is capable of relatively easily quantifying the liquid crystal particularly in a manufacturing process of a large liquid crystal panel.
For example, the liquid crystal drop amount required for a cell gap of 3 μm in a 10-inch element panel is about 100 μl (microliter), and the liquid crystal drop amount required for a cell gap of 5 μm in a 22-inch element panel is , About 0.75 ml (milliliter).
These amounts are such that the quantification at the time of dropping can be performed without any trouble using a commercially available dispenser.
[0011]
However, in the manufacturing process of the reflective liquid crystal display element (LCOS), the required amount of liquid crystal to be dropped is 0.1 μl (microliter) to 1 μm because the size is small and the cell gap is narrow as described above. It was a very small amount of 0.2 μl (microliter), and it was extremely difficult to quantitatively determine such a small volume with good reproducibility using a commercially available dispenser and to discharge and drop.
[0012]
Therefore, in order to realize the quantification of this minute amount of droplets and the ejection and dropping, a special device that is not commercially available and capable of accurate quantification and ejection and dropping is required, which increases the manufacturing cost of the element. There was a problem.
Further, it has been found that when a small amount of droplets are dropped using such a special device, there is a problem that a constant amount of droplets cannot be stably dropped and sufficient reproducibility cannot be obtained.
[0013]
Further, in the method of charging and dropping the liquid crystal, since the liquid crystal is made to have a high resistivity of 10 ¹⁴ Ω · m or more in order to function as a display element, when the liquid crystal passes through a path such as a pipe in the dispenser. And a small amount of droplets were not stably charged, causing variations in the amount of droplets.
In addition, there has been a problem that reproducibility of the drop cannot be obtained due to the influence of the charging state around the dispenser around which the liquid is dropped and the electrical influence from the outside of the apparatus.
Due to the various problems described above, the liquid crystal display device manufactured by the conventional manufacturing method and apparatus has low image quality, low productivity, and high cost.
[0014]
Therefore, the problem to be solved by the present invention is that a very small amount of liquid crystal droplets can be dropped on a substrate with good reproducibility, and a high-quality liquid crystal display device with high image quality and productivity can be manufactured. And a method and apparatus for manufacturing a liquid crystal display element.
[0015]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration as means.
That is, claim 1 has a first substrate 7 and a second substrate 8 having a pixel electrode 11 formed on the surface thereof, and is provided between the first and second substrates 7 and 8 by a sealing adhesive 13. In a method for manufacturing a liquid crystal display element comprising sealing the liquid crystal 12 and bonding the first and second substrates 7 and 8,
A sealing adhesive application step of forming a frame of the sealing adhesive 13 around the pixel electrode 11 by coating, and a droplet 12a of the liquid crystal 12 in the frame in a space electrically shielded from the outside. A dropping step of dropping while discharging the liquid crystal.
[0016]
Further, the present invention has a first substrate 7 and a second substrate 8 having a pixel electrode 11 formed on the surface thereof, and is provided between the first and second substrates 7 and 8 by a sealing adhesive 13. In an apparatus for manufacturing a liquid crystal display element, which seals the liquid crystal 12 and bonds the first and second substrates 7 and 8,
A seal adhesive applying means 53 for forming a frame of the seal adhesive 13 around the pixel electrode 11 by coating, a dropping means 54 for dropping the droplets 12a of the liquid crystal 12 into the frame, A shielding means 55 surrounding the substrate 8 and the drip means 54 and electrically shielding the inside and the outside thereof, and a charge eliminating means 18 for eliminating electricity in a space inside the shielding means 55 including the droplet 12a. An apparatus 51 for manufacturing a liquid crystal display element 50 comprising:
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic front view showing an embodiment of the apparatus for manufacturing a liquid crystal display element of the present invention,
FIG. 2 is a schematic plan view showing another embodiment of the apparatus for manufacturing a liquid crystal display element of the present invention,
FIG. 3 is a perspective view and a cross-sectional view illustrating a liquid crystal display device manufactured by the liquid crystal display device manufacturing apparatus of the present invention.
FIG. 4 is a perspective view illustrating another substrate configuration of the liquid crystal display element manufactured by the liquid crystal display element manufacturing apparatus of the present invention,
FIG. 5 is a schematic view for explaining a main part of a liquid crystal display element manufacturing apparatus according to the present invention.
[0018]
FIG. 1 shows an embodiment of an apparatus 51 for manufacturing a liquid crystal display element 50 according to the present invention.
This apparatus is composed of a plurality of blocks corresponding to a manufacturing process, and is configured in an in-line type in which each block is arranged in order from the left side to the right side of the drawing according to the manufacturing process.
The liquid crystal display element 50 is manufactured while moving each block by the transport device 22 provided in each block.
[0019]
First, the configuration of an example of the liquid crystal display element 50 manufactured by the manufacturing apparatus 51 will be described with reference to FIG.
FIG. 3A is a perspective view for explaining the assembling, and FIG. 3B is a sectional view at a position corresponding to the AA section in FIG. 3A after the assembling.
[0020]
The liquid crystal display element 50 is of a reflection type, and has on one surface a glass substrate 7 in which an antireflection film 9 and a transparent electrode film 10 are formed on opposite surfaces, and a pixel electrode (hereinafter referred to as a display area) 11. The silicon IC substrate 8 is disposed to face, a seal adhesive 13 is applied in a frame shape around the display area 11, and the substrates 7, 8 are fixed while sealing the liquid crystal 12 in the frame. I have.
The seal adhesive 13 is made of a spacer ball and an adhesive for keeping the gap (cell gap) between the two substrates 2 and 4 constant.
[0021]
Next, each block in the manufacturing apparatus 51 of the above-described liquid crystal display element 50 will be described with reference to FIG.
[0022]
<First block>
The first block is a substrate supply stage 1.
The silicon IC substrate 8 set on the transfer device 7 is transferred to the second block by the transfer device 22 and supplied to the second block. The display area 11 is formed on the silicon IC substrate 8 in advance.
[0023]
The silicon IC substrate 8 is not limited to the above-described one-element unit form (see FIG. 3), but may be a wafer form capable of obtaining a plurality of liquid crystal display elements as shown in FIG.
FIG. 4 shows a state in which the sealing adhesive 13 is applied in a frame shape around each display area on the circular silicon IC substrate 8A on which a plurality of display areas (not shown) are formed. On the other hand, the glass substrate 7A has a rectangular shape.
[0024]
<Second block>
The second block is a sealing adhesive application chamber 2.
The coating chamber 2 includes a transport device 22, a coating head 14 which is a coating unit 53 for coating the seal adhesive 13, and a coating control device 15 for controlling a coating width and a coating amount.
[0025]
In this block, a seal adhesive 13 is applied in a frame shape around the display area 11 on the silicon IC substrate 8 transported from the first block.
In the case of the silicon IC substrate 8A in the form of a wafer, the seal adhesive 13 is applied in a frame shape around each display area.
[0026]
After this coating, the silicon IC substrate 8 is transported by the transport device 22 to the third block. Details of the seal adhesive 13 will be described later.
[0027]
<Third block>
The third block is a liquid crystal dropping chamber 3.
The liquid crystal dropping chamber 3 includes a transport device 22, a dropping head 16 having a needle 16 a which is a dropping unit 54 for dropping the liquid crystal 12, and a dropping control device 17 for performing quantitative measurement and controlling dropping. I have.
In the vicinity of the tip of the needle 16a of the dropping head 16, a charge removing electrode 18b of the charge removing device 18 is provided. Further, a shielding shield 19 for electrically shielding the silicon IC substrate 8 and the dropping head 16 from the outside is provided.
[0028]
The shield 19 and the static eliminator 18 will be described in detail with reference to FIG.
A dropping head 16 for dropping the liquid crystal 12 is disposed above the silicon IC substrate 8 set on a dropping table 20 which is grounded.
FIG. 2 shows a state immediately before dropping of the liquid crystal 12 when the droplet of the liquid crystal 12 adheres to the tip of the needle 16 a of the dropping head 16.
[0029]
A shielding shield 19 is provided around the drip head 16 and the silicon IC substrate 8. The shielding shield 19 is formed of a grounded metal net (or plate).
Therefore, the inside surrounded by the shielding shield 19 and the dropping table 20 as the shielding means 55 is electrically shielded from the outside and is not charged.
[0030]
On the other hand, the static eliminator 18 as a static eliminator is of a high-voltage application type, and is composed of a high-voltage transformer 18a, a static-eliminating electrode 18b for applying a high-voltage ion stream, and a high-voltage cable 18c for connecting these electrodes. An ion current is generated from the neutralizing electrode by corona discharge due to application of a high voltage, and the neutralized object is neutralized.
[0031]
The high-voltage transformer 18a is arranged outside the shielding shield 19, and a static elimination electrode 18b is arranged near the tip of the needle 16a of the drip head 16, and each is connected by a high-voltage cable 18c. The static eliminator 18 is not limited to the high-voltage application type.
[0032]
Even if the droplets 12a of the liquid crystal 12 to be dropped are charged by the charge removing device 18, the charges can be removed and the droplets 12a can be dropped in an electrically neutralized state. In addition, since the inside of the shielding shield is also made a space neutralized by neutralization, the liquid crystal can be dropped with high reproducibility.
[0033]
In FIG. 1, the silicon IC substrate 8 transported from the second block is set at a predetermined position on the dropping table 20.
From the tip of the needle 16 a of the dropping head 16, the droplet 12 a quantified by the dropping control device 17 is dropped on the display area 11 of the silicon IC substrate 8 surrounded by the seal adhesive 13.
In this dropping, since the charge removing device 18 is operated as described above, the droplet 12a is dropped with the charge removed.
[0034]
After the completion of the dropping of the predetermined amount, the silicon IC substrate 8 is transferred by the transfer device 22 to the fourth block.
[0035]
<Fourth block>
The fourth block is a press room 4 in which temporary bonding is performed.
The press chamber 4 includes a transfer device 22, a press platen including an upper platen 23a and a lower platen 23b, a press device 24, a pressure control device 25 for controlling the pressure in the room, and a vacuum pump 26. ing.
[0036]
The glass substrate 7 previously loaded and supplied to the press chamber 4 by a supply device (not shown) is set below the upper platen, and the silicon IC substrate 8 transported from the third block is set above the lower platen. You.
[0037]
After the positioning of the substrates 7 and 8 is performed, the air in the room is evacuated by the vacuum pump 26 until a substantially vacuum state of 1 Pa or less is obtained.
[0038]
After the evacuation is completed, the upper and lower platens 23a and 23b are brought close to each other by the press device 24, and pressed until the seal adhesive 13 comes into close contact with the silicon IC substrate 8 and the glass substrate 7.
[0039]
Thereafter, the pressure in the room is increased from a substantially vacuum state of 1 Pa or less to an atmospheric pressure state by the pressure control device 25.
[0040]
As the pressure increases, the space (hereinafter, referred to as the liquid crystal cell portion 21) sealed by the silicon IC substrate 8, the glass substrate 7, and the sealing adhesive 13 gradually decreases its cell gap, and the sealing adhesive is applied. The temporary bonding is completed when the spacer mixed in the agent 13 comes into contact with both substrates 7 and 8 to form a predetermined uniform cell gap.
At this time, in order to reduce the cell gap, in addition to the increase in the pressure, the upper and lower platens 23a and 23b may be brought close to each other by the press device 24 to press the silicon IC substrate 8 and the glass substrate 7 in an auxiliary manner. .
[0041]
The liquid crystal display element 8 on which the temporary bonding is completed is transported to the fifth block by the transport device 22.
[0042]
<Fifth block>
The fifth block is a fixing chamber 5 in which the actual bonding is performed.
The fixing chamber 5 includes a transfer device 22 and a UV light irradiation device 26.
[0043]
The UV light irradiation device 26 irradiates a predetermined amount of UV light to the seal adhesive 13 of the liquid crystal display element 50 that has been temporarily bonded and conveyed from the fourth block and has been completed.
As a result, the seal adhesive 13 is hardened, and the glass substrate 7 and the silicon IC substrate 8 are completely fixed, and the liquid crystal 12 dropped in the third block is completely sealed, and the actual bonding is completed.
Depending on the adhesive curing system used, the adhesive may be completely cured by heating after UV light irradiation.
[0044]
Thereafter, the liquid crystal display element 50 is transported by the transport device 22 to the sixth block.
[0045]
<Sixth block>
The sixth block 6 is a completed substrate stage.
The liquid crystal display element 50, which has been completely bonded in the fifth stage, is transported to this stage, where it is supplied to a step of performing the same processing as a normal liquid crystal display element, such as cell cutting.
[0046]
In the present embodiment, each of the second to fifth blocks has been described as a continuous and integrated manufacturing apparatus. However, each block is an independent apparatus, and a transport apparatus is arranged between the apparatuses. It may be a manufacturing device.
Also, each block is not necessarily continuous, and another step may be provided between each block.
[0047]
Although the above-described embodiment is an in-line type manufacturing apparatus, an embodiment in which the arrangement of each block is changed to a cluster type will be described with reference to FIG.
This modified embodiment is a manufacturing apparatus 51A in which a substrate supply robot 52 is disposed at the center, and the above-described first to sixth blocks 1 to 6 are disposed around the substrate supply robot 52 so as to surround the substrate supply robot 52.
[0048]
The substrate supply robot 52 supplies and unloads substrates to and from each block. A glass substrate 7 is also prepared on the substrate supply stage 1 and supplied to the press chamber 4 by the robot 52.
In this figure, the above-mentioned wafer type silicon IC substrate 8A is shown as the silicon IC substrate.
[0049]
It goes without saying that the manufacturing apparatus of the present invention is not limited to the in-line type or the cluster type, and if the work of each block is executed in the order described above, the arrangement form of each block in the manufacturing apparatus may be an installation environment or the like. Can be set freely according to
[0050]
Next, the seal adhesive 13 will be described in detail.
As described above, in this embodiment, the liquid crystal 12 dropped on the display area 11 comes into direct contact with the uncured seal adhesive 13 applied around the display area 11.
If the components of the seal adhesive 13 dissolve into the liquid crystal 12 side in this state, a defect on the displayed image will occur. Therefore, it is necessary that the liquid crystal 12 and the seal adhesive 13 have no material compatibility. There is.
[0051]
Therefore, the seal adhesive 13 has a component configuration in which the concentration of the organic solvent as the base agent is reduced.
In other words, the viscosity of the seal adhesive 13 is set to be equal to or higher than the predetermined viscosity so that compatibility with the liquid crystal is lost, thereby preventing occurrence of a defect on a displayed image.
[0052]
The viscosity of the seal adhesive for preventing the occurrence of the defect may be 300,000 mPa · s or more, and a suitable seal adhesive having this viscosity is, for example, World Lock No. manufactured by Kyoritsu Chemical Sangyo Co., Ltd. . 717 ("World Lock" is a registered trademark of Kyoritsu Chemical Industry Co., Ltd.).
[0053]
The embodiment of the present invention is not limited to the above-described configuration, and can be modified without departing from the gist of the present invention.
[0054]
【The invention's effect】
As described in detail above, according to the method of manufacturing a liquid crystal display element of the present invention, a seal adhesive application step of forming a seal adhesive frame around a pixel electrode by application, and an electric shield from the outside. In the space, a dropping step of dropping liquid crystal droplets while discharging the liquid in the frame is included, so that a very small amount of liquid crystal droplets can be dropped onto the substrate with good reproducibility, and image quality can be improved. In addition, it is possible to produce a low-cost liquid crystal display element with high productivity.
[0055]
Further, according to the liquid crystal display element manufacturing apparatus of the present invention, a seal adhesive applying means for forming a frame of the seal adhesive around the pixel electrode by applying, and a drip means for dropping liquid crystal droplets into the frame. A shielding means for surrounding the substrate on which the pixel electrode is formed and the dropping means and electrically shielding the inside and outside thereof; and a charge removing means for removing electricity in a space inside the shielding means including liquid crystal droplets. As a result, a very small amount of liquid crystal droplets can be dropped onto the substrate with good reproducibility, and an effect of producing a low-cost liquid crystal display device with high image quality and productivity can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic front view showing one embodiment of a device for manufacturing a liquid crystal display element of the present invention.
FIG. 2 is a schematic plan view showing another embodiment of the apparatus for manufacturing a liquid crystal display element of the present invention.
3A and 3B are a perspective view and a cross-sectional view illustrating a liquid crystal display element manufactured by the liquid crystal display element manufacturing apparatus according to the invention.
FIG. 4 is a perspective view illustrating another substrate configuration of a liquid crystal display element manufactured by the liquid crystal display element manufacturing apparatus of the present invention.
FIG. 5 is a schematic view for explaining a main part of a liquid crystal display element manufacturing apparatus according to the present invention.
FIG. 6 is a diagram illustrating a general configuration of a liquid crystal display element.
[Explanation of symbols]
1 Substrate supply stage (first block)
2 (Seal adhesive) application chamber (second block)
3 Liquid crystal dripping chamber (third block)
4 Press room (temporary bonding part) (4th block)
5 Fixing room (final bonding part) (fifth block)
6 Completed substrate stage (sixth block)
7,7A glass substrate (first substrate)
8.8A silicon IC substrate (second substrate)
9 Anti-reflection film 10 Transparent electrode film 11 Pixel electrode (display area)
DESCRIPTION OF SYMBOLS 12 Liquid crystal 12a Droplet 13 Seal adhesive 14 Application head 15 Application control device 16 Dropping head 16a Needle 17 Dropping control device 18 Static elimination device (means)
Reference numeral 18a High-voltage transformer 18b Static electricity removing electrode 18c High-voltage cable 19 Shielding shield 20 Dropping table 21 Liquid crystal cell unit 22 Transport device 23a Upper surface plate 23b Lower surface plate 24 Press device 25 Pressure control device 26 UV light irradiation device 50 Liquid crystal display elements 51, 51A Manufacturing device 52 substrate supply robot 53 coating means 54 dropping means 55 shielding means

Claims (2)

A first substrate and a second substrate having a pixel electrode formed on a surface thereof;
In a method of manufacturing a liquid crystal display element, a liquid crystal is sealed between the first and second substrates with a seal adhesive, and the first and second substrates are bonded to each other.
A seal adhesive application step of forming the seal adhesive frame around the pixel electrode by application,
A method of dropping the liquid crystal droplets into the frame while removing electricity in a space that is electrically shielded from the outside, the method comprising: A first substrate and a second substrate having a pixel electrode formed on a surface thereof;
In a manufacturing apparatus for a liquid crystal display device, a liquid crystal is sealed between the first and second substrates with a seal adhesive, and the first and second substrates are bonded to each other.
Seal adhesive applying means for forming a frame of the seal adhesive around the pixel electrode by applying,
Dropping means for dropping the liquid crystal droplets in the frame,
Shielding means for surrounding the second substrate and the dropping means, and electrically shielding the inside and outside thereof,
A device for removing static electricity from a space inside the shielding means including the liquid droplets.

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