JP4659956B2 - Manufacturing method of liquid crystal display element - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display element and a liquid crystal display element, and in particular, a liquid crystal display element characterized by a method for sealing liquid crystal injected into a cavity formed between two substrates constituting the liquid crystal display element. It relates to a manufacturing method.
[0002]
[Prior art]
Conventionally, in the manufacturing process of a liquid crystal display element, two substrates 2 and 3 are bonded together with a seal portion formed and applied in a frame-like pattern with a sealing material, and then thermocompression bonding is performed to produce a multi-substrate 6. Thereafter, the multi-substrate 6 is cut into a stick shape or a single cell shape to open the liquid crystal injection port 5.
[0003]
As shown in FIG. 4, the opening operation of the liquid crystal injection port 5 at this time is performed by cutting the opposing positions of the two substrates 2 and 3 constituting the multi-substrate 4, respectively. It is formed substantially flush. Then, liquid crystal is injected from the liquid crystal injection port 5 into the cavity between the bonded substrates 2 and 3, and then the liquid crystal injection port 5 is sealed with a sealing material 8.
[0004]
In general, the liquid crystal injection port 5 is sealed by using a two-component epoxy resin, a photocurable or visible light acrylic resin, etc. as a resin sealing material, a dispenser, a spring pin, or a roller. For example, a method of applying and sealing to the liquid crystal inlet 5 is used.
[0005]
[Problems to be solved by the invention]
By the way, in the liquid crystal display element, the substrates 2 and 3 are becoming lighter and thinner. For example, in a plastic liquid crystal display element (hereinafter, plastic liquid crystal display element 1), the substrate thickness is 0.1 mm to 0.4 mm. Something very thin is also used.
[0006]
However, when the thicknesses of the substrates 2 and 3 are reduced in this way, the sealing material 8 hangs laterally from the end surfaces of the substrates 2 and 3 due to the surface tension as shown in FIG. 5 (FIG. 5 (1)). Therefore, it is easy to protrude (FIG. 5 (2)), and therefore it is necessary to improve the coating accuracy. In the case where the substrates 2 and 3 are glass substrates, the problem is that the dripping or protruding sealing material 8 can be removed without damaging the glass substrate using polishing or a cutter. In the case where the substrates 2 and 3 are plastic substrates, the method of forced removal by polishing, cutter, etc. can easily damage the plastic substrate, and the manufacturing condition management such as adjustment of the amount of sealing material applied can be controlled. There was a problem that it was severe and workability was very bad.
[0007]
Further, in the plastic liquid crystal display element 1, a seal portion is designed in which a dummy inlet is connected to and extended from the open end of the liquid crystal inlet 5, and the liquid crystal inlet 5 and the dummy inlet are sealed after liquid crystal sealing. A method of cutting the substrate from the connecting portion has also been developed, but this method has problems in productivity and cost, such as an increase in the cutting step in the work process and an increase in consumption of the sealing material 8.
[0008]
The present invention has been made in view of the above points, and a liquid crystal display capable of manufacturing a product with stable quality by preventing the sealing material from dripping or protruding to the substrate, and improving productivity and reducing cost. An object of the present invention is to provide an element manufacturing method and a liquid crystal display element.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing a liquid crystal display element according to the present invention includes forming a frame-shaped seal portion having a liquid crystal inlet on one of two substrates on which a transparent electrode is formed, and forming the other. After bonding the substrate and cutting the substrates so that the liquid crystal injection port is opened to form cells, liquid crystal is injected from the liquid crystal injection port into the cavity surrounded by the seal portion, and the liquid crystal of the cell In the method of manufacturing a liquid crystal display element in which an inlet is sealed with a sealing material, the substrate is cut such that the liquid crystal inlet side edge of the other substrate is closer to the liquid crystal inlet side edge of the other substrate. A step is provided so as to protrude in the extending direction of the liquid crystal, and the liquid crystal injection port is sealed with the sealing material. The liquid crystal injection port is opened upward, and the liquid crystal injection port is opened upward. The surface facing one of the substrates is directed upward, and The cutting end surface formed by the cutting line of the one substrate is arranged to be inclined at a predetermined set angle so that it extends in the horizontal direction, and a predetermined 25 ° ± 5 ° with respect to the set angle. The sealing material is applied from the direction of the coating angle .
[0010]
According to the present invention, the sealing material applied to the liquid crystal injection port can be extended along the step by generating a step at both substrate end portions on the liquid crystal injection port side of the cell. The sealing material can be prevented from dripping and adhering to the substrate surface of the display element, and a liquid crystal display element free from contamination on the substrate surface can be easily produced.
[0011]
Further, the present invention is characterized in that the width between the liquid crystal inlet side edges of the two substrates is in a range of 1.5 mm ± 0.5 mm.
[0012]
By forming the width within a range of 1.5 mm ± 0.5 mm as in the present invention, the above-described effects can be reliably obtained.
[0013]
Furthermore, the present invention is characterized in that the predetermined set angle is 55 ° ± 5 ° .
[0014]
According to the present invention, pressurization using a pressurizing jig can be appropriately performed, and a sealing operation is easily performed.
[0015]
Further, the present invention is characterized in that the sealing of the liquid crystal injection port with the sealing material is performed by setting in a pressure jig that makes the in-plane gap uniform.
[0016]
According to the present invention, it is possible to prevent the sealing material from coming into contact with the end surface portion of the other substrate protruding from the one substrate due to the step, and the sealing material from dripping on the surface of the other substrate. it can.
[0018]
ADVANTAGE OF THE INVENTION According to this invention, the contamination by the protrusion and dripping of the sealing material with respect to a board | substrate can be prevented reliably, and it can respond to thickness reduction of a board | substrate.
[0020]
According to the present invention, the above-described effects can be obtained with certainty.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.
[0022]
First, the substrates 2 and 3 used for manufacturing the liquid crystal display element of the present embodiment are large plastic substrates 2 and 3 which are divided into necessary numbers later to obtain a desired plastic liquid crystal display element 1. It is what. Of the two substrates 2 and 3, one substrate 2 is subjected to a patterning process and an alignment process process. Specifically, as the substrates 2 and 3 of this embodiment, a plastic substrate having a thickness of 0.1 mm is used. Then, after patterning the transparent electrode into a predetermined shape on one substrate 2, an alignment film is applied and baked, and a rubbing process is performed.
[0023]
After that, a sealing material is applied by applying a sealing material in the substrate bonding / panel dividing step. The sealing material may be applied by screen printing or dispenser drawing. However, when applying the sealant, it is applied thicker than the diameter of the spacer to be used, and then the substrate is laminated. In the process, it is extended to the diameter of the spacer.
[0024]
In this embodiment, the shape of the seal portion 4 is a frame having a liquid crystal inlet 5 protruding outward as shown in FIG.
[0025]
Further, as the sealing material used here, a thermosetting type sealing material, for example, an epoxy type thermosetting sealing material having a conventionally used physical property is used. And before entering into the bonding process following a sealing material application process, a pre-cure process is performed and leveling of a sealing material and solvent removal are performed.
[0026]
On the other hand, on the opposing substrate 3, a transparent electrode (not shown) is formed by patterning into a predetermined shape, an alignment film is applied and rubbed, and then spacers (not shown) are dispersed.
[0027]
Next, the substrate 2 on which the seal portion 4 is formed and the substrate 3 on which spacers are dispersed are accurately overlapped and thermocompression bonded so that alignment marks (not shown) formed on the respective substrates 2 and 3 match. Through the seal curing process, a multi-substrate 6 is obtained that becomes a liquid crystal layer having a thickness substantially the same as the diameter of the spacer.
[0028]
Then, cutting for opening the liquid crystal injection port 5 of the substrates 2 and 3 constituting the large-sized multi-substrate 6 is performed so as to provide a step at the cut portions of both the substrates 2 and 3. Is obtained.
[0029]
That is, as shown in FIG. 1, cutting for opening the liquid crystal injection port of one substrate 2 is performed at the end portion of the seal portion 4 that forms the liquid crystal injection port 5. A cutting line L1 parallel to the formation side of the entrance 5 is performed, and the cutting for opening the liquid crystal injection port 5 of the other substrate 3 is parallel to the cutting line L1 and more than the cutting line L1. The cutting is performed on a cutting line L2 having a predetermined width (hereinafter referred to as a step width W) and spaced from the side of the sealing portion 4 where the liquid crystal injection port 5 is formed. The step width W, which is the width between the edges of the substrates 2 and 3 on the liquid crystal injection port 5 side, is preferably 1.5 mm ± 0.5 mm. In this embodiment, the step width W is 1.5 mm. .
[0030]
Subsequently, liquid crystal is injected from the liquid crystal injection port 5 into the cavity surrounded by the seal portion 4 of each cell 7. In this embodiment, the cell 7 is set at a predetermined angle (hereinafter referred to as a set angle α) to a pressure jig (not shown) for uniformizing the in-plane gap. This set angle α is desirably 55 ° ± 5 °, and in this embodiment, the set angle α is 55 °.
[0031]
As shown in FIG. 2, the set of the cells 7 at this time is such that the liquid crystal injection port 5 opens upward, and the liquid crystal of one of the substrates 2 and 3 constituting the cell 7 is liquid crystal. The surface of the substrate 3 that is cut in such a manner that the edge of the substrate 3 is cut out so as to protrude from the substrate edge on the side of the inlet 5 is directed upward, and the cutting line It arrange | positions so that the cut end surface of the board | substrate 2 formed of L1 may extend in a horizontal direction. Between the cells 7, the adjacent cells 7 are aligned so that the surfaces of the substrates 2 and 3 face each other, and a pressure sponge is interposed between the cells 7.
[0032]
In this state, a predetermined pressure is applied by the pressure jig, and the in-plane gap is made uniform by blowing out excess liquid crystal under pressure. Subsequently, with respect to the liquid crystal inlet 5 of each cell 7 opened upward using a spring pin, the surface of the substrate 3 facing the one substrate 2 and directed upward is predetermined. A photocurable resin as the sealing material 8 is applied from an angle (hereinafter referred to as an application angle β), and the sealing material 8 is cured by irradiation with light. That is, the coating angle β is an angle with respect to the set angle α, and the coating angle β is preferably 25 ° ± 5 °. In the present embodiment, the coating angle β is 25 °.
[0033]
The sealing material 8 applied to the liquid crystal injection port 5 in this way forms a step at the position of the side edge of the liquid crystal injection port 5 on both the substrates 2 and 3, and thus, FIGS. As shown in FIG. 2, the flow is along the cutting end surface of the substrate 2 formed by the cutting line L1 and extending in the horizontal direction, so that it does not hang down or protrude from the side surfaces of the substrates 2 and 3, Since the sagging or protruding sealing material 8 is not forcibly removed by polishing or a cutter, the thin plastic liquid crystal display element 1 can be manufactured without damaging the substrates 2 and 3. .
[0034]
In addition, the sealing method in this invention is not restricted to the method using the spring pin of the above-mentioned embodiment, The sealing material 8 to be used is not restricted to the photocurable resin used in the above-mentioned embodiment.
[0035]
Further, the cell 7 when the pressure is applied by the pressure jig and the liquid crystal inlet 5 is sealed by the sealing material 8 may be formed in a stick shape as shown in FIG. The plastic liquid crystal display element 1 may be formed in a single cell size.
[0036]
Further, the substrate edge on the side opposite to the liquid crystal injection port of each cell 7 uses the cutting lines L1 and L2 at that time when both substrates 2 and 3 are cut from the multi-substrate 6 to open the liquid crystal injection port 5 of the cell 7. However, there may be a step in the edge position, or the edge position may be trimmed by adding a cutting step, and the processing is arbitrary.
[0037]
Next, specific experimental examples of the method for manufacturing the liquid crystal display element of the present invention described above will be described.
[0038]
Experimental example 1
Two substrates 2 and 3 made of plastic having a thickness of 0.2 mm were bonded together and thermocompression bonded to produce a multi-substrate 6. Then, when the two substrates 2 and 3 are opened when the liquid crystal injection port of each cell 7 is opened, the step width W is varied in units of 0.5 mm from 0.5 mm to 4.0 mm, so that eight types of cells are provided. 7 was formed in a stick shape. Liquid crystal was injected into each cell 7 having different step widths W, and set in the above-described pressure jig. At this time, the set angle α is 55 °, the application angle β of the sealing material 8 with a spring pin is 25 °, and the dripping or protrusion of the sealing material 8 in each cell 7 in which the step width W is different. Was tested.
[0039]
As a result, the cell 7 having a step width W of 0.5 mm caused the sealing material 8 to sag because the step width W was small. On the other hand, the sealing material 8 does not sag when the thickness is 2.5 mm or more, but stress is easily applied to the substrate 3 on the side protruding from the one substrate 2 by handling in the steps after the sealing step, and the seal is peeled off. As a result, it was found that the step width W is preferably in the range of 1.5 mm ± 0.5 mm.
[0040]
Experimental example 2
Two plastic substrates 2 and 3 each having a thickness of 0.2 mm are bonded and thermocompression bonded to form a multi-substrate 6, and the two substrates 2 and 3 are cut when the liquid crystal injection port 5 of each cell 7 is opened. A cell 7 having a step width W of 1.5 mm was formed in a stick shape.
[0041]
Liquid crystal was injected into the stick-like cell 7 and set in the pressure jig described above. At this time, the set angle α was varied in units of 10 ° from 45 ° to 65 °, and the state of pressure applied to the cell and the occurrence of sealing sag were tested. The application angle β of the sealing material 8 with the spring pin at this time was fixed at 25 °.
[0042]
As a result, when the set angle α was 45 °, the set stick-like cell 7 was displaced from the pressurizing jig when the pressurization pressure was increased, and uniform pressurization could not be performed. Further, when the set angle α is 65 ° or more, there is a high probability that the sealing material 8 sags or protrudes. Therefore, it was found that the set angle α is preferably set in the range of 55 ° ± 5 °.
[0043]
Experimental example 3
Two plastic substrates 2 and 3 each having a thickness of 0.2 mm are bonded and thermocompression bonded to form a multi-substrate 6, and the two substrates 2 and 3 are cut when the liquid crystal injection port 5 of each cell 7 is opened. A cell 7 having a step width W of 1.5 mm was formed in a stick shape.
[0044]
Liquid crystal is injected into the stick-shaped cell 7, the set angle α is set to 55 ° in the pressure jig, and the application angle β of the sealing material 8 with the spring pin is set to 10 ° to 40 °. It was varied in units of 10 ° to test whether the sealing material 8 sag or protruded.
[0045]
As a result, when the application angle β is set to 10 °, the sealing material 8 comes into contact with the end surface portion of the other substrate 3 protruding from the one substrate 2 due to the step when the spring pin is lowered. Then, sagging of the sealing material 8 occurred on the surface of the other substrate 3 . Therefore, it is not desirable that the coating angle β is 10 ° or less. If the coating angle β is 40 ° or more, dripping of the sealing material 8 occurs conversely on the surface of the one substrate 2, so that the coating angle β is 25 °. It has been found that ± 5 ° is desirable.
[0046]
Experimental Example 4
The tests disclosed in Examples 1 to 3 were tried for the plastic substrates 2 and 3 having a thickness of 0.1 mm and 0.4 mm, respectively. The same results as in the example could be obtained.
[0047]
In addition, this invention is not limited to the thing of the said embodiment, A various change is possible as needed.
[0048]
【The invention's effect】
As described above, according to the method of manufacturing a liquid crystal display element according to the present invention, it is possible to reliably prevent the sealing material from protruding or sagging from the substrate, and to prevent the substrate from being thinned. The liquid crystal display element using the manufactured substrate can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a shape of a seal portion and a cutting line of each substrate in a method for manufacturing a liquid crystal display element according to the present invention. FIG. FIG. 3 is an explanatory view showing a flow direction of a sealing material during liquid crystal sealing in the present embodiment. FIG. 4 shows a shape of a seal portion and a cutting line of each substrate in a conventional method for manufacturing a liquid crystal display element. Explanatory drawing [FIG. 5] Schematic cross-section showing problems with conventional liquid crystal sealing [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Plastic liquid crystal display elements 2 and 3 Board | substrate 4 Sealing part 5 Liquid crystal inlet 6 Multi-substrate 7 Cell 8 Sealing material L1 Cutting line L2 Cutting line

Claims (4)

A frame-like seal portion having a liquid crystal injection port is formed on one of the two substrates on which the transparent electrode is formed and bonded to the other substrate, and each of the substrates is opened so that the liquid crystal injection port is opened. In the method of manufacturing a liquid crystal display element, after forming the cell by cutting, injecting liquid crystal from the liquid crystal injection port into the cavity surrounded by the seal portion, and sealing the liquid crystal injection port of the cell with a sealing material.
The substrate is cut by providing a step so that the liquid crystal inlet side edge of the other substrate protrudes in the extending direction of the substrate from the liquid crystal inlet side edge of the one substrate ,
The sealing of the liquid crystal injection port with the sealing material is such that each cell opens the liquid crystal injection port upward, the surface of the other substrate facing the one substrate is directed upward, and The cutting end surface formed by the cutting line of one of the substrates is disposed obliquely at a predetermined set angle so that the cut end surface extends in the horizontal direction, and a predetermined coating of 25 ° ± 5 ° is further applied to the set angle. A method for manufacturing a liquid crystal display element, which is performed by applying a sealing material from an angle direction .   2. The method for manufacturing a liquid crystal display element according to claim 1, wherein the width between the liquid crystal inlet side edges of the two substrates is set to a width within a range of 1.5 mm ± 0.5 mm. The method for manufacturing a liquid crystal display element according to claim 1, wherein the predetermined set angle is 55 ° ± 5 ° .   4. The liquid crystal according to claim 1, wherein the sealing of the liquid crystal injection port with the sealing material is performed by setting in a pressure jig that makes the in-plane gap uniform. 5. A method for manufacturing a display element.

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