JP2011170024A - Method for manufacturing liquid crystal display elements - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing liquid crystal display elements for improving productivity, wherein liquid crystal is not contaminated by a sealing material and cell gap adjustment is easily performed. <P>SOLUTION: The photo-curable sealing material 21 is applied in a circular shape around a display pixel region 4, on a liquid crystal driving substrate 6 including a display pixel region 4 in which a plurality of pixel electrodes 3 are formed. Then, the liquid crystal 23 is supplied on the display pixel region 4. A transparent electrode substrate 15 in which transparent electrodes 13 are formed and liquid crystal driving substrate 6 are stuck together via the sealing material 21 so that the plurality of pixel electrodes 3 may face the transparent electrodes 13, and the liquid crystal 23 may not come into contact with the sealing material 21. Then, light UV1 of a predetermined illuminance is emitted onto an inner surface layer section A21 of the sealing material 21. Cell gap adjustment is performed between the transparent electrode substrate 15 and the liquid crystal driving substrate 6, and light UV2 of higher illuminance than the predetermined illuminance is emitted onto the whole sealing material 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a liquid crystal display element.

  In recent years, liquid crystal display elements have been widely used in display fields such as projectors, projection televisions, and head mounted displays.

  Here, a general manufacturing method of the liquid crystal display element will be described.

First, a sealing material is applied in an annular shape with a discontinuous portion for each element on at least one of a liquid crystal driving substrate and a transparent electrode substrate.
Next, the liquid crystal driving substrate and the transparent electrode substrate are bonded together with a sealing material.
Further, the bonded liquid crystal driving substrate and transparent electrode substrate are divided for each element.
The discontinuous portion described above serves as an injection port for injecting liquid crystal into the gap between the liquid crystal driving substrate and the transparent electrode substrate.

Next, liquid crystal is injected into the gap from the injection port for each element under a reduced pressure environment.
Further, after adjusting the cell gap for each element, the inlet is sealed with a sealant.
Through the above steps, a liquid crystal display element is manufactured.

  However, in the above-described method for manufacturing a liquid crystal display element, the liquid crystal is injected under a reduced pressure environment for each divided element, or the injection port is sealed for each element with a sealing agent. Have the problem of being bad.

An example of means for solving the above-described problem is disclosed in Patent Document 1.
The means disclosed in Patent Document 1 is applied to a liquid crystal driving substrate or a transparent electrode substrate by applying a sealing material in a ring shape without discontinuities for each element, dropping liquid crystal inside the ring, and then reducing the pressure. The sealing material is cured after the liquid crystal driving substrate and the transparent electrode substrate are bonded together under the environment and the cell gap is adjusted.

However, with the means disclosed in Patent Document 1, when the liquid crystal driving substrate and the transparent electrode substrate are bonded together, the liquid crystal comes into contact with the uncured sealing material, so that the sealing material is eluted into the liquid crystal. May contaminate the LCD.
The contamination of the liquid crystal becomes a factor that deteriorates the display quality of the liquid crystal display element.

An example of means for preventing liquid crystal contamination is disclosed in Patent Document 2.
The means disclosed in Patent Document 2 is a method in which the surface layer portion of the uncured sealing material is semi-cured over the whole, and then the liquid crystal driving substrate and the transparent electrode substrate are bonded together.

JP 2005-148215 A JP 2008-293000 A

However, the means disclosed in Patent Document 2 has a problem that it is difficult to set curing conditions for semi-curing the entire surface layer portion of the sealing material.
If the surface layer of the sealing material is not sufficiently cured, the sealing material will elute into the liquid crystal and contaminate the liquid crystal.
On the other hand, if the surface layer part of the sealing material is excessively cured, the cell gap adjustment becomes difficult due to the cured surface layer part.

  Further, the means disclosed in Patent Document 2 requires a protrusion forming step of forming a plurality of protrusions for breaking through the hardened surface layer portion on the substrate on which the sealing material is not formed. Since the manufacturing process of a display element becomes complicated, productivity is bad and the further improvement is desired.

  Therefore, an object of the present invention is to provide a method for manufacturing a liquid crystal display element that can easily adjust the cell gap without causing the liquid crystal to be contaminated by the sealing material and improve the productivity.

In order to solve the above problems, the present invention provides the following method for manufacturing a liquid crystal display element.
1) A sealing material (21) having a photo-curing property is annularly formed on a liquid crystal driving substrate (6) having a display pixel region (4) in which a plurality of pixel electrodes (3) are formed so as to surround the display pixel region. A sealing material application process for applying, a liquid crystal supply process for supplying liquid crystal (23) onto the display pixel region after the sealing material application process, and a transparent electrode (13) formed after the liquid crystal supply process. The transparent electrode substrate (15) and the liquid crystal drive substrate are bonded via the sealing material so that the plurality of pixel electrodes and the transparent electrode face each other and the liquid crystal and the sealing material do not contact each other. A bonding process for combining, a first light irradiation process for irradiating light (UV1) with a predetermined illuminance on the inner peripheral surface layer portion (A21) of the sealing material after the bonding process, and the first light irradiation process After A cell gap adjustment step for adjusting a cell gap between the electrode substrate and the liquid crystal driving substrate, and a second irradiation of light (UV2) with an illuminance higher than the predetermined illuminance on the entire sealing material after the cell gap adjustment step. A process for producing a liquid crystal display element (30).
2) In the first light irradiation step, the light having the predetermined illuminance is applied to the inner peripheral surface layer portion through a light shielding mask (25) whose region corresponding to the inner peripheral surface layer portion is a light transmission region (A25). Irradiating, the manufacturing method of the liquid crystal display element of 1 description characterized by the above-mentioned.

  According to the present invention, the cell gap can be easily adjusted without the liquid crystal being contaminated by the sealing material, and the productivity can be improved.

It is a flowchart for demonstrating the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the liquid-crystal drive board | substrate preparation process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the transparent electrode substrate preparation process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the sealing material application | coating process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the liquid crystal dropping process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the board | substrate bonding process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the sealing material semi-hardening process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the sealing material semi-hardening process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the cell gap adjustment process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the sealing material main hardening process in the Example of the manufacturing method of the liquid crystal display element of this invention. It is typical sectional drawing for demonstrating the element separation process in the Example of the manufacturing method of the liquid crystal display element of this invention.

The preferred embodiments of the present invention will be described with reference to FIGS.
In the embodiment of the method for manufacturing a liquid crystal display element according to the present invention, a plurality of liquid crystal display elements can be obtained at one time from one semiconductor wafer and one transparent substrate. However, in FIGS. For convenience, only one liquid crystal display element is shown from the beginning of the process.

<Example>
In this embodiment, a method for manufacturing a reflective liquid crystal display element will be described as an example. However, the present invention is not limited to this, and the method for manufacturing a liquid crystal display element according to the present invention is applied to a transmission liquid crystal display element. It is also possible to apply.

[Liquid crystal drive substrate manufacturing process]
As shown in FIG. 1 (step 1) and FIG. 2, first, a drive circuit unit 2 for driving a liquid crystal 23 to be described later for each pixel electrode 3 is formed on a semiconductor substrate 1 using a known semiconductor process.
Next, a plurality of pixel electrodes 3 are formed on the semiconductor substrate 1. A region where the plurality of pixel electrodes 3 are formed is a display pixel region 4 for displaying an image.
Further, an alignment film 5 is formed on the semiconductor substrate 1 so as to cover the plurality of pixel electrodes 3 (display pixel regions 4), and the liquid crystal driving substrate 6 is manufactured.

In the example, a silicon (Si) wafer was used as the semiconductor substrate 1.
In the embodiment, as the pixel electrode 3, a light reflection type electrode containing at least one of aluminum (Al) and silver (Ag) as a main component is formed.
In the example, an inorganic alignment film such as a rubbed polyimide film or a silicon oxide film was formed as the alignment film 5.

[Transparent electrode substrate manufacturing process]
As shown in FIG. 1 (step 2) and FIG. 3, an antireflection film 12 is formed on one surface 11a side of a transparent substrate 11 having light transmittance, and a transparent electrode 13 having light transmittance and orientation on the other surface 11b side. The film 14 is sequentially formed to produce the transparent electrode substrate 15.

In the example, a glass substrate was used as the transparent substrate 11.
In the example, an inorganic oxide film such as an aluminum oxide film was formed as the antireflection film 12.
In the example, an ITO (indium tin oxide) film was formed as the transparent electrode 13.
In the example, an inorganic alignment film such as a rubbed polyimide film or a silicon oxide film was formed as the alignment film 14.

The order of the above-mentioned “liquid crystal driving substrate manufacturing process” and “transparent electrode substrate manufacturing process” is not limited.
The “liquid crystal driving substrate manufacturing process” may be performed after the “transparent electrode substrate manufacturing process”, or the “transparent electrode substrate manufacturing process” and the “liquid crystal driving substrate manufacturing process” may be performed in parallel.

[Sealing material application process]
As shown in FIG. 1 (step 3) and FIG. 4, the sealing material 21 is applied on the liquid crystal driving substrate 6 in an annular shape so as to surround the display pixel region 4.

In the embodiment, as the sealing material 21, a material in which spacers 21b which are spherical particles having a predetermined diameter are dispersed in an uncured resin 21a is used.
In the example, a combined curing resin using ultraviolet rays and heat was used as the resin 21a.
In addition, the sealing material 21 is not limited to an Example, What is necessary is just to contain the resin which has photocurability at least.

  In the embodiment, the sealing material 21 is applied to the liquid crystal driving substrate 6 side. However, the present invention is not limited to this. For example, the sealing material 21 may be applied to the transparent electrode substrate 15 side. The sealing material 21 may be applied to the 6 side and the transparent electrode substrate 15 side, respectively.

[Liquid crystal dropping process]
As shown in FIG. 1 (step 4) and FIG. 5, a predetermined amount of liquid crystal 23 is dropped onto the display pixel region 4 surrounded by the sealing material 21.

[Board bonding process]
As shown in FIG. 1 (step 5) and FIG. 6, the liquid crystal drive substrate 6 and the transparent electrode substrate 15 are replaced with the pixel electrode 3 (or alignment film 5) and the transparent electrode 13 (or alignment film 14) under a reduced pressure environment. Paste them so that they face each other.
At this time, the liquid crystal 23 is in contact with the alignment film 5 of the liquid crystal driving substrate 6 and the alignment film 14 of the transparent electrode substrate 15, but not in contact with the uncured sealing material 21.

  In the example, the liquid crystal drive substrate 6 and the transparent electrode substrate 15 were bonded together in a vacuum chamber depressurized to a predetermined pressure.

[Seal material semi-curing process]
As shown in FIG. 1 (step 6) and FIG. 7, low-intensity ultraviolet rays are applied to the inner peripheral surface portion A21 including the inner peripheral surface of the annularly applied sealing material 21 using a light shielding mask 25 under a reduced pressure environment. Irradiate UV1.
In the light shielding mask 25, a region corresponding to the inner peripheral surface layer portion A21 is a light transmitting region A25, and regions other than the light transmitting region A25 are regions B21 other than the inner peripheral surface layer portion A21 of the sealing material 21 and display pixel regions. 4 is a light shielding region B25 so that ultraviolet rays UV1 are not irradiated.

The inner peripheral surface portion A21 (resin 21a) irradiated with the low-intensity ultraviolet ray UV1 is in a semi-cured state (see FIG. 8).
The semi-cured state here refers to a state where the sealing material 21 (resin 21 a) is cured to the extent that it does not elute into the liquid crystal 23 when the liquid crystal 23 comes into contact with the sealing material 21.

At this time, in the sealing material 21, the region B21 (resin 21a) other than the inner peripheral surface layer portion A21 in a semi-cured state is in an uncured state.
At this time, the liquid crystal 23 is not in contact with the inner peripheral surface layer portion A21 in which the sealing material 21 is in a semi-cured state.
At this time, the space S surrounded by the liquid crystal driving substrate 6, the transparent electrode substrate 15, the sealing material 21, and the liquid crystal 23 is a closed space where the pressure is reduced.

[Cell gap adjustment process]
As shown in FIG. 1 (step 7) and FIG. 9, the cell gap between the liquid crystal drive substrate 6 and the transparent electrode substrate 15 and the distribution range thereof are set to a predetermined value and a predetermined distribution range under an atmospheric pressure environment. Adjust the cell gap.
At the time of this cell gap adjustment, the liquid crystal 23 expands toward the outer peripheral portion, so that the void S in the reduced pressure state is filled with the liquid crystal 23.

When adjusting the cell gap, the liquid crystal 23 comes into contact with the inner peripheral surface portion A21 of the sealing material 21, but the inner peripheral surface layer portion A21 (resin 21a) is in a semi-cured state, and therefore the sealing material 21 (resin 21a) is in the liquid crystal 23. Elution into the inside can be prevented.
Further, even when the inner peripheral surface layer portion A21 is in a state where the curing has progressed further than the desired semi-cured state when the UV light UV1 having low illuminance is irradiated in the semi-curing process of the sealing material, Since the sealing material 21 in the region B21 easily spreads in the outer peripheral direction, the shape of the sealing material 21 easily changes. For this reason, cell gap adjustment can be performed easily and with high accuracy.
Further, when the cell gap is adjusted, the sealing material 21 is deformed on the outer peripheral side, but the inner peripheral surface layer portion A21 is in a semi-hardened state, and therefore hardly deforms on the inner peripheral portion side. Therefore, the volume change due to the cell gap adjustment in the region filled with the liquid crystal 23 can be suppressed, so that the cell gap adjustment can be performed easily and with high accuracy.

[Seal material main curing process]
As shown in FIG. 1 (step 8) and FIG. 10, using the light shielding mask 27, the entire sealing material 21 is irradiated with ultraviolet rays UV2 having a higher illuminance than the ultraviolet rays UV1 in a state where the display pixel region 4 is shielded from light.
In the light shielding mask 27, a region corresponding to the sealing material 21 is a light transmission region A27, and a region other than the light transmission region A27 is a light shielding region B27 so that the display pixel region 4 is not irradiated with the ultraviolet rays UV2. .

Further, as shown in FIG. 1 (step 9) and FIG. 11, the bonded structure 29 of the liquid crystal driving substrate 6 and the transparent electrode substrate 15 is heated at a predetermined temperature for a predetermined time, thereby providing a sealing material. 21 is fully cured.
Here, the main curing means that the cured sealing material 21 (resin 21a) has a desired characteristic (for example, adhesion strength between the liquid crystal driving substrate 6 and the transparent electrode substrate 15 and water absorption). .

[Element isolation process]
As shown in FIG. 1 (step 10), a plurality of liquid crystal display elements 30 (see FIG. 10) are obtained at a time by dividing the bonded structure 29 that has undergone the above-described process into each element.

  According to the above-described method for manufacturing a liquid crystal display element, in particular, after the cell gap is adjusted in a state where only the inner peripheral surface layer portion of the sealing material on the side in contact with the liquid crystal is semi-cured, the entire sealing material is fully cured. This makes it possible to easily adjust the cell gap without the liquid crystal being contaminated by the sealing material, and it is not necessary to form a plurality of convex portions for breaking through the hardened surface layer portion, thereby improving productivity. The effect is.

  The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.

For example, in the embodiment, the light shielding mask 25 is used to irradiate the ultraviolet ray UV1 only on the inner peripheral surface layer portion including the inner peripheral surface of the sealing material. However, the present invention is not limited to this.
Instead of the light shielding mask 25, an optical member such as an optical fiber or a lens may be used so that the ultraviolet ray UV1 is condensed in a spot shape and scanned in an annular shape along the inner periphery of the sealing material. Only the inner peripheral surface layer portion including the inner peripheral surface of the sealing material may be cured by condensing in a line shape.

In the embodiment, the light shielding mask 27 is used to shield the display pixel region and irradiate the entire sealing material with the ultraviolet ray UV2. However, the present invention is not limited to this.
Instead of the light shielding mask 27, an optical member such as an optical fiber or a lens may be used so that the ultraviolet ray UV2 is condensed in a spot shape and scanned in an annular shape along the inner periphery of the sealing material. Only the inner peripheral surface layer portion including the inner peripheral surface of the sealing material may be cured by condensing in a line shape.

DESCRIPTION OF SYMBOLS 1_ Semiconductor substrate 2_ Drive circuit part 3_ Pixel electrode 4_ Display pixel area 5, 14_ Alignment film 6_ Liquid crystal drive substrate 11_ Transparent substrate, 11a, 11b_ Surface 12_ Antireflection film 13_ Transparent electrode 15_ Transparent electrode substrate 21_ Seal material, 21a_ Resin, 21b_ Spacer 23_liquid crystal 25, 27_light shielding mask 29_bonding structure 30_liquid crystal display element A21_inner peripheral surface layer, UV1, UV2_ultraviolet light, S_gap

Claims (2)

A sealing material application step of annularly applying a photocurable sealant so as to surround the display pixel area on a liquid crystal driving substrate having a display pixel area in which a plurality of pixel electrodes are formed;
A liquid crystal supply step for supplying liquid crystal onto the display pixel region after the sealing material application step;
After the liquid crystal supplying step, the transparent electrode substrate on which the transparent electrode is formed and the liquid crystal driving substrate are arranged such that the plurality of pixel electrodes and the transparent electrode face each other, and the liquid crystal and the sealing material do not contact each other. Then, a bonding step of bonding through the sealing material,
A first light irradiation step of irradiating the inner peripheral surface layer portion of the sealing material with light having a predetermined illuminance after the bonding step;
A cell gap adjusting step for adjusting a cell gap between the transparent electrode substrate and the liquid crystal driving substrate after the first light irradiation step;
After the cell gap adjustment step, a second light irradiation step of irradiating the entire sealing material with light having an illuminance higher than the predetermined illuminance,
A method for producing a liquid crystal display element, comprising:   The said 1st light irradiation process irradiates the said inner peripheral surface layer part through the light-shielding mask whose area | region corresponding to the said inner peripheral surface layer part is a light transmissive area | region with the said predetermined illumination intensity light. Item 2. A method for producing a liquid crystal display element according to Item 1.

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