JP2001013510A - Manufacture of plastic liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a fused decomposed substance from contaminating a liquid crystal in the liquid crystal element by half-cutting a plastic substrate with laser beam machining, cleaning and removing the fused decomposed substance, subsequently parting it and injecting the liquid crystal. SOLUTION: Two plastic substrates 1 are stuck via a sealant 2 composed of an epoxy type adhesive or the like. An opening part (an injection port) 3 is preliminarily provided on a part of the sealant 2. The outside part of the substrates 1 is half-cut by focusing a laser beam 4 on the two substrates 1, regulating the output of oscillation and fusing the substrates 1 from the outside halfway to the thickness direction of the substrates 1. The fused decomposed substance 5 of the substrates is cleared and removed by spraying an organic solvent such as acetone or toluene or water or the like from a spray nozzle on the substrates. The substrates 1 are parted by bending the half-cut notch of the substrates 1. The injection port 3 for injecting the liquid crystal is exposed to the outside. The liquid crystal is injected fully into the liquid crystal element through the injection port 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a liquid crystal device using a plastic substrate.

[0002]

2. Description of the Related Art In a liquid crystal element, a transparent electrode pattern made of indium tin oxide (ITO) or the like is formed on an insulating substrate, and two insulating substrates are bonded to each other via a sealing material having an opening with the transparent electrodes facing each other. After the alignment, the liquid crystal is injected from the opening (injection hole) of the sealant into the gap between the two insulating substrates surrounded by the sealant and sealed.

In recent years, liquid crystal devices have been applied to small and lightweight portable electronic devices, and plastic substrates instead of glass have been adopted as insulating substrates due to demands for weight reduction. Polyether sulfone (PES) as plastic material,
A gas barrier layer formed by coating silicon oxide (SiO2) on polyethylene terephthalate (PET), modified acrylic resin, or the like is used. This means that the density of glass is approximately 2.4 g / cm3, whereas the density of these engineering plastic materials is approximately 1.
The reason is that it is significant in reducing the weight of the liquid crystal element because it is as small as 4 g / cm 3, and that it has an advantage that it is harder to break even when stress is applied because it has more elastic properties than glass.

However, when manufacturing industrially using a plastic substrate, it is necessary to partially change the process from the method of manufacturing using a glass substrate. In the case of an insulating substrate made of a glass material, a desired cracking position is formed by forming a minute crack line on the glass surface with a scribe wheel, and then pressure is applied to the minute crack line to bring stress to the side opposite to the glass surface and the wafer is cut. However, since the plastic material has a strong elastic property, a method using a glass material cannot be adopted when dividing the plastic substrate into individual liquid crystal elements.
Then, as one method of dividing the plastic substrate, there is a method of melting and dividing the plastic substrate with a carbon dioxide laser.

FIG. 4 is a cross-sectional view of a liquid crystal element immediately before a dividing step in a conventional method of manufacturing a liquid crystal element using a plastic substrate. A gas barrier layer (not shown) made of silicon oxide (SiO2) or the like for preventing gas such as moisture from entering from outside the liquid crystal element when the liquid crystal element is formed on the plastic substrate 1 together with indium tin oxide (ITO)
A transparent conductive film pattern (not shown) is formed. The two plastic substrates 1 are bonded together via a sealing material 2. At this time, an opening (injection hole) is provided in advance in a part of the sealing material 2, and this opening is used for injecting liquid crystal into an inner region of the plastic substrate surrounded by the sealing material after the plastic substrate is divided. It becomes a hole.

FIG. 5 is a cross-sectional view of a liquid crystal element, showing a process of melting and dividing a plastic substrate with a carbon dioxide gas laser. Since the plastic material absorbs the oscillation wavelength light (about 10 μm) of the carbon dioxide gas laser, it can be melt-processed. The division is achieved by irradiating the plastic substrate 1 with a laser beam 4 to melt and divide a part of the plastic substrate. As a result, the injection hole 3 is exposed.

Hereinafter, liquid crystal is injected from the injection hole into the empty cell of the divided liquid crystal element, and the injection hole is sealed with an adhesive to obtain a liquid crystal element.

[0008]

However, the melting and cutting of a plastic substrate by laser processing involves the melting and decomposition of a plastic material, so that the melt decomposition product 5 adheres to the cross section. The melt decomposed product contains a polymer compound constituting a plastic material that has been decomposed into low molecules, and thus is dissolved in the liquid crystal or injected into the device together with the liquid crystal at the time of injection. Therefore, there are problems such as the inability to obtain the original optical characteristics of the liquid crystal element and a liquid crystal element lacking reliability.

An object of the present invention is to provide a method for manufacturing a liquid crystal element which has the original optical characteristics of a liquid crystal element and also ensures reliability without mixing a molten and decomposed product of a plastic substrate into the liquid crystal element. It is to provide.

[0010]

In order to achieve the above object, a method of manufacturing a liquid crystal device according to the present invention employs the following means.

In the method for manufacturing a liquid crystal element according to the present invention,
After the two plastic substrates are bonded together with a sealing material having an opening, a half-cutting step of melting the outer portions of the two plastic substrates by laser processing, a cleaning step of cleaning and removing molten decomposed products, and a half-cutting And a liquid crystal injecting step of injecting a liquid crystal through an opening of the sealant.

[Operation] The present invention includes a half-cutting step of melting the outer portions of the two plastic substrates by laser processing while the two plastic substrates are bonded together with a sealing material. The melted and decomposed product of the plastic substrate generated in this half-cutting process does not adhere to the injection hole portion because the plastic substrate has not been divided. Next, there is provided a washing step of washing and removing the melt decomposition product. The molten decomposed product of the plastic substrate generated in the previous half-cutting process is removed in this process, but during this process, the plastic substrate is not divided yet, so the plastic decomposed product or chemicals required for cleaning may contaminate the injection hole part. There is no. And a subsequent dividing step of dividing the two half-cut plastic substrates,
A liquid crystal element that has the original optical characteristics and also ensures reliability by preventing the molten decomposed product of the plastic substrate from entering the liquid crystal element during the liquid crystal injection step of injecting liquid crystal from the opening of the sealing material. Can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a liquid crystal device manufacturing method according to the best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a view for explaining a half-cutting step in which two plastic substrates are bonded together with a sealing material having an opening, and then the outer portions of the two plastic substrates are melted by laser processing. FIG.

On the plastic substrate 1, a gas barrier layer (not shown) made of silicon oxide (SiO2) or the like for preventing gas such as moisture from entering from outside the liquid crystal element when the liquid crystal element is formed, and indium tin oxide (ITO) or the like A transparent conductive film pattern (not shown) is formed. The two plastic substrates 1 are bonded together via a sealing material 2 made of an epoxy adhesive or the like. At this time, an opening (injection hole) is provided in advance in a part of the sealing material 2, and this opening is used for injecting liquid crystal into an inner region of the plastic substrate surrounded by the sealing material after the plastic substrate is divided. It becomes hole 3. Before bonding the two plastic substrates, an alignment film is formed on the plastic substrate, and then an alignment process is performed by rubbing with a rotating body covered with a cloth, or a spacer made of plastic particles is sprayed on the alignment film. Although there is a spraying process, it is omitted to avoid complicating the drawing.

In the half-cutting step of melting the outer portions of the two plastic substrates by laser processing, the laser beam 4 emitted from the carbon dioxide laser oscillator is focused on the two plastic substrates 1 to adjust the oscillation output. However, this is achieved by dissolving the plastic substrate 1 from the outside to the middle of the thickness direction of the plastic substrate 1. The amount of the half cut can be controlled by changing the output and the focus of the laser light. After this step is completed, the two plastic substrates 1 are notched so that they are easily separated. In addition, the melt decomposition product 5 by laser processing of plastic substrate 5
Adheres to the periphery of the cut of the plastic substrate, but does not adhere to the periphery of the injection hole 3.

As shown in FIG. 2, the washing step for washing and removing the molten decomposed product is a method of spraying an organic solvent such as acetone or toluene or water or the like which dissolves the decomposed product of the plastic substrate from the spray nozzle 6, or an organic solvent. This can be achieved by a method of wiping with a cloth impregnated with a solvent, water, or the like. Since the molten decomposed product 5 is a low-molecular organic substance obtained by decomposing a plastic substrate material, it can be dissolved in an organic solvent or wiped off with water. After the cleaning step, the remaining organic solvent, water, and the like may be blown off with dry air to dry the cut portion where the plastic substrate is half-cut.

The dividing step of dividing the two half-cut plastic substrates is achieved by bending the cut half-cut portions of the plastic substrate 1 as shown in FIG. By bending and dividing in this manner, the injection hole 3 for injecting the liquid crystal appears for the first time outside, and the periphery of the injection hole is not contaminated with the melted and decomposed material of the plastic substrate material.

Although a liquid crystal injecting step of injecting liquid crystal through the opening of the sealing material is not shown, a liquid crystal container filled with liquid crystal and a liquid crystal element into which liquid crystal is injected are put in a vacuum chamber, and the liquid crystal is injected. After the injection hole of the element is immersed in the liquid crystal container, the inside of the chamber is returned to atmospheric pressure with nitrogen or the like. This is achieved by filling the liquid crystal into the liquid crystal element through the injection hole. Thereafter, the injection hole is sealed with an adhesive to obtain a liquid crystal element.

[0019]

According to the method of the present invention for manufacturing a liquid crystal element comprising a plastic substrate, the plastic substrate is half-cut by laser processing from the outside of each substrate to a point in the thickness of the substrate, and the molten and decomposed product of the plastic substrate is washed. Since the liquid crystal is injected after being separated after the removal, the liquid crystal in the liquid crystal element is not contaminated by the melted and decomposed product, and a liquid crystal element having the original optical characteristics of the liquid crystal element and not inferior in reliability can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal device, illustrating a half-cutting step of melting outer portions of two plastic substrates by laser processing in a method for manufacturing a liquid crystal device of the present invention.

FIG. 2 is a cross-sectional view of the liquid crystal device, illustrating a cleaning step of cleaning and removing a molten decomposition product in the method for manufacturing a liquid crystal device of the present invention.

FIG. 3 is a cross-sectional view of the liquid crystal element, illustrating a dividing step of dividing the two half-cut plastic substrates in the method for manufacturing a liquid crystal element of the present invention.

FIG. 4 is a cross-sectional view of a liquid crystal element immediately before a dividing step in a conventional liquid crystal element manufacturing method.

FIG. 5 is a cross-sectional view of a liquid crystal element, showing a step of melting and dividing a plastic substrate with a carbon dioxide laser in a conventional method of manufacturing a liquid crystal element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic substrate 2 Sealing material 3 Injection hole 4 Laser beam 5 Melt decomposition product 6 Spray nozzle

Claims (1)

[Claims] After bonding two plastic substrates with a sealing material having an opening, the two plastic substrates are laminated by laser processing.
A half-cutting step of melting the outer portions of the two plastic substrates, a cleaning step of cleaning and removing the molten decomposed product, a dividing step of dividing the two half-cut plastic substrates, and a liquid crystal from the opening of the sealing material. And a liquid crystal injecting step of injecting the liquid crystal.