JP3449308B2 - Light processing equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phototreatment device for irradiating an object to be irradiated with ultraviolet rays to react a substance which causes a photochemical reaction applied to the object to be irradiated, and further to an ultraviolet curing type. The present invention relates to an optical processing device suitable for bonding two substrates using an adhesive, and more particularly to an optical processing device suitable for bonding liquid crystal substrates in a manufacturing process of a liquid crystal display element.

[0002]

2. Description of the Related Art A protective film, adhesive, paint, ink, resist, etc. applied to an object to be processed is irradiated with ultraviolet light from a photoprocessing device to cure, dry, melt, soften, etc. However, recently, light irradiation processing such as hardening and bonding of a protective film of an optical disk substrate on which aluminum is deposited as an information recording layer and bonding of a liquid crystal substrate provided with a color filter are performed. It is being actively conducted.

A liquid crystal substrate is made by laminating two transparent or semi-transparent substrates and enclosing a liquid crystal between them. An ultraviolet curable adhesive is used to adhere the two substrates to ultraviolet rays. It is performed by irradiating and causing a photochemical reaction in the adhesive. Adhesion of two liquid crystal substrates with an ultraviolet curing adhesive is disclosed in, for example, Japanese Patent Laid-Open No. 8-146436.

The wavelength of the ultraviolet curable adhesive is 3
A material having an ultraviolet ray of 65 nm as a curing wavelength is generally used. A discharge lamp that efficiently radiates this curing wavelength is selected as the light source lamp.
As a discharge lamp that efficiently radiates ultraviolet rays in the vicinity of nm, there is a metal halide lamp in which a metal such as iron and mercury are enclosed.

FIG. 4 shows an example of the spectral radiant flux of a metal halide lamp containing iron and mercury. As you can see, the wavelength of this metal halide lamp is 3
In addition to the ultraviolet light having a wavelength of around 65 nm, far ultraviolet light having a wavelength of 300 nm or less and infrared light having a wavelength of 750 nm or more are also emitted. Therefore, when the light emitted from the metal halide lamp is directly applied to the two liquid crystal substrates that are the objects to be irradiated, infrared rays are absorbed by the substrates and the temperature of the liquid crystal substrate rises. At this time, 2
Of the two substrates, the one closer to the light source lamp has a larger temperature rise, so a difference in the amount of thermal expansion occurs between the two substrates, and if the two substrates are bonded in this state, they will be positioned between the two substrates. Misalignment occurs. When the amount of displacement is 2 to 3 μm or more, the liquid crystal display element with fine pixels becomes defective.

When the object to be irradiated is other than one in which two substrates are bonded together, for example, in order to cure the protective film of the optical disk, a photocurable acrylic resin is applied to the surface of the polycarbonate disk, and the wavelength is 300. Even when the light-curable acrylic resin is dried and solidified by irradiating light of up to 400 nm, if the disk absorbs infrared rays and rises in temperature, a "warp" exceeding the standard occurs on the disk, resulting in a defective product. Also,
When the photocurable ink is dried by irradiating light having a wavelength of 300 to 400 nm, such as drying of printing of a film, for example, label printing of a PET bottle, when the plastic film absorbs infrared rays and rises in temperature, There is a problem that the plastic film expands and contracts, and in the case of multicolor printing, color shift occurs.

[0007]

As described above, when the light irradiation process is performed, a problem occurs if the temperature of the object to be irradiated rises. Therefore, a heat ray absorption filter is arranged between the light source lamp and the object to be irradiated. It can be considered to suppress the temperature rise of the irradiation object. Then, for example, in a manufacturing process of a liquid crystal display element, a heat ray absorption filter is provided between the light source lamp and the liquid crystal substrate in order to prevent the temperature rise of the liquid crystal substrate.
No. 799.

A colored glass filter is generally used as the heat ray absorbing filter. This colored glass filter contains metal atoms in the glass, and transmits short-wavelength light well, but absorbs long-wavelength light to remove or attenuate long-wavelength light.

However, when the colored glass filter is irradiated with light having a wavelength of 330 nm or less, the characteristics of the colored glass filter are deteriorated, and the transmittance of short wavelength light is lowered,
The transmittance of ultraviolet rays near the curing wavelength of 365 nm of the ultraviolet curable adhesive also remarkably decreases. As described above, since the metal halide lamp contains deep ultraviolet rays having a wavelength of 300 nm or less, when a colored glass filter is arranged between the metal halide lamp and the liquid crystal substrate to irradiate light,
Due to the deterioration of the characteristics of the colored glass filter, the transmittance of the curing wavelength is reduced, and it takes a long time to cure the adhesive, and further, the adhesive is not sufficiently cured. Therefore, for example, in the case of laminating liquid crystal display elements, a decrease in throughput and poor adhesion are caused.

Further, since the colored glass filter absorbs or absorbs long-wavelength light to remove or attenuate the long-wavelength light, the absorbed long-wavelength light is converted into heat to raise the temperature of the colored glass filter itself. . Therefore, the object to be irradiated may be heated by the radiant heat from the colored glass filter. The temperature rise can be prevented by directly blowing the cooling air onto the colored glass filter or the object to be irradiated. However, if the object to be irradiated needs to be manufactured in a clean environment such as a liquid crystal display element, if cooling air is inadvertently blown onto the colored glass filter or the object to be irradiated, this cooling air is set in advance in the manufacturing environment. It disturbs the flow of clean air and causes dust.

Therefore, a first object of the present invention is to provide an optical processing device capable of performing optical processing without deteriorating the characteristics of the heat ray absorption filter for suppressing the temperature rise of the object to be irradiated, A second object is to provide an optical processing device that does not deteriorate the characteristics of the heat ray absorption filter and that does not raise the temperature of the irradiated object due to the radiant heat of the colored glass filter.

[0012]

In order to achieve the first object, the invention of claim 1 irradiates an object to be irradiated with a substance causing a photochemical reaction with ultraviolet rays to cause the photochemical reaction. In a light processing device for reacting a substance, a light source unit for irradiating light including ultraviolet light, a far-ultraviolet light cut filter for removing or attenuating light having a wavelength of 330 nm or less,
A heat ray absorption filter for removing or attenuating light having a wavelength of 750 nm or more is provided, and the light of the light source unit passes through the far ultraviolet ray cut filter and then passes through the heat ray absorption filter to irradiate the irradiation object.

In order to achieve the second object, the invention of claim 2 is the invention of claim 1 in which a quartz plate is arranged on the object side of the heat ray absorbing filter, and the quartz plate is placed between the heat ray absorbing filter and the quartz plate. Form a ventilation path through which cooling air flows. Also,
According to a third aspect of the invention, in the first aspect of the invention, a ventilation passage through which cooling air flows is formed between the far ultraviolet ray cut filter and the heat ray absorption filter.

According to a fourth aspect of the present invention, there is provided an optical processing device capable of achieving the first or second object, wherein the object to be irradiated is two substrates, and the substrates are UV-curable adhesive. The present invention relates to an optical processing device for bonding with a chemical, and the invention of claim 5 relates to an optical processing device used in a step of bonding liquid crystal substrates.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an embodiment of the invention according to claim 1. In FIG. 1, the irradiation target is the liquid crystal display element L. That is, an ultraviolet curable adhesive S having a curing wavelength of 365 nm is applied to the peripheral edges of the two transparent or translucent liquid crystal substrates P1 and P2 so as to seal the space between the liquid crystal substrates P1 and P2. Has been done. The liquid crystal display element L is mounted on the quartz plate 6 which is a holding table.

A lamp 1 is arranged below a quartz plate 6 on which a liquid crystal display element L which is an object to be irradiated is mounted.
Lamp 1 is a metal halide lamp in which iron and mercury are enclosed in a tubular bulb, and the lamp radiation output is 16 kW.
Is. The spectral radiant flux is as shown in FIG. 4 and efficiently radiates light near 365 nm. Lamp 1
Is covered with a gutter-shaped mirror 2, a lamp 1 and a mirror 2
It constitutes the light source section. The direct light of the lamp 1 and the reflected light of the mirror 2 are emitted toward the liquid crystal display element L.
The mirror 2 may be a total reflection mirror that reflects all the light from the lamp 1, but it is preferable to use a “cold mirror” in which a multilayer film that transmits heat rays of long wavelength is deposited.

The lamp 1 and the liquid crystal display element L which is the object to be irradiated
A far-ultraviolet ray cut filter 3 and a heat ray absorption filter 4 which is a colored glass filter are arranged between the two. Here, the far ultraviolet ray cut filter 3 is arranged on the lamp 1 side, and the heat ray absorption filter 4 is arranged on the liquid crystal display element L side. The far-ultraviolet cut filter 3 is a quartz plate on which a multilayer film designed to reflect light having a wavelength of 330 nm or less is deposited, and the transmittance is, for example, 50% or less in the range of 300 to 330 nm, and 300 nm. The following is 0%. That is, light of 300 nm or less is completely removed, and 300 to 3
It has a characteristic of attenuating light having a wavelength of 30 nm by 50% or more. Since various colored glass filters having different absorption wavelength ranges are commercially available, the heat ray absorption filter 4 used in the present invention has a transmittance of 50% in the range of 720 to 730 nm and 1001 to 1100 nm. 1% or less is selected, but any material having a property of completely removing light having a wavelength of 750 nm or more or attenuating it by 50% or more may be used.

The light in the vicinity of 365 nm emitted from the lamp 1 is transmitted through the far-ultraviolet ray cut filter 3 and the heat ray absorption filter 4 in this order and applied to the liquid crystal display element L, as described later. Then, in a state where the liquid crystal display element L is pressed from above by a pressing means (not shown), the adhesive S
Two liquid crystal substrates P1, which are cured by 5 nm ultraviolet light
P2 is pasted together. When the bonding process is completed,
Liquid crystal is injected into the space between the two liquid crystal substrates P1 and P2 from an injection port provided in the peripheral portion of the liquid crystal display element L.

FIG. 5 shows the spectral radiant flux of the light transmitted through the far-ultraviolet ray cut filter 3. Far-ultraviolet rays having a wavelength of 330 nm or less are completely removed or largely attenuated. Then, the light transmitted through the far-ultraviolet ray cut filter 3 enters the heat ray absorption filter 4 formed of a colored glass filter. Figure 6
Shows the spectral radiant flux of the light transmitted through the heat ray absorption filter 4. The heat ray absorption filter 4 almost eliminates the light having a long wavelength of 750 nm or more, and only the ultraviolet light around 365 nm is the irradiated liquid crystal. The display element L is irradiated and the adhesive S having a curing wavelength of 365 nm is efficiently cured.

As described above, the far-ultraviolet cut filter 3 removes far-ultraviolet rays having a wavelength of 330 nm or less, or the light greatly attenuated enters the heat-ray absorption filter 4 formed of a colored glass filter, so that the characteristics of the heat-ray absorption filter 4 are deteriorated. Suppressed. FIG. 7 shows a characteristic deterioration curve of the heat ray absorption filter. In FIG. 7, the dotted curve shows the characteristic deterioration curve of the conventional example in which the light emitted from the discharge lamp is directly incident on the heat ray absorption filter without using the far-ultraviolet ray cut filter, which is initially about 85 to 90%. Wavelength 36
The transmittance of 5 nm light decreases greatly with irradiation time,
When the irradiation time is 100 hours, it is about 60 to 65%, which is about 25 to 30% lower. Therefore, ultraviolet rays having a wavelength of 365 nm, which is the curing wavelength of the adhesive, are greatly attenuated. On the other hand, the solid curve shows the characteristic deterioration curve in the example of the present invention, but the decrease in the transmittance of light having a wavelength of 365 nm is about 10% even after irradiation for 90 hours. Therefore, even if irradiation is performed for a long time, the attenuation of ultraviolet rays having a wavelength of 365 nm, which is the curing wavelength of the adhesive, can be suppressed to half that of the conventional case, and the decrease in throughput of the liquid crystal display element L and the adhesion failure can be prevented.

Further, since the light of the spectral radiant flux shown in FIG. 6 is transmitted to the liquid crystal display element L, which is the object to be irradiated, after passing through the far ultraviolet ray cut filter 3 and the heat ray absorption filter 4,
The liquid crystal substrate is not irradiated with infrared rays, and the temperature of the liquid crystal display element L hardly rises. Therefore, the two liquid crystal substrates P1 and P2 are
The temperature difference is extremely small, and the "deviation" between the two liquid crystal substrates P1 and P2 due to the difference in thermal expansion does not occur, and the product yield can be improved.

FIG. 2 shows an embodiment of the invention of claim 2. The liquid crystal display element L which is the object to be illuminated and the lamp 1 and the mirror 2 which are the light source section are the same as those of the embodiment of the invention of claim 1 shown in FIG. The heat ray absorption filter 4 has a large size and is not commercially available.
A plurality of heat ray absorption filters 4 having a size of about 3 are arranged on the far-ultraviolet ray cut filter 3. The characteristics of the far ultraviolet ray cut filter 3 and the heat ray absorption filter 4 are as described above.

The holding frame 7 for holding the heat ray absorbing filter 4 and the far-ultraviolet ray cut filter 3 has an air supply port 71 and an exhaust port 72 formed on its side surface, and its upper and lower surfaces are open.
The heat ray absorption filter 4 and the far ultraviolet ray cut filter 3 are held so as to cover the opened lower surface of the holding frame 7. The blower 8 for cooling air is connected to the air supply port 71 through the duct 9, and the exhaust port 72 is also connected to the duct 9 that guides the exhausted air to the outside. The quartz plate 5 is held so as to cover the open upper surface of the holding frame 7, and the closed space defined by the heat ray absorbing filter 4, the quartz plate 5 and the holding frame 7 is provided in the cooling air ventilation passage 10. Has become. And
When the blower 8 operates, the cooling air flowing through the ventilation passage 10
The heat ray absorption filter 4 that absorbs long-wavelength light and rises in temperature is cooled. The blower 8 is connected to the exhaust port 72
An exhaust type (pull type) cooling device provided on the side may be used.

FIG. 3 shows an embodiment of the invention according to claim 3. Here, one heat ray absorption filter 4 having the same size as the far ultraviolet ray cut filter 3 is used, and the far ultraviolet ray cut filter 3 and the heat ray absorption filter 4 are held so as to cover the lower surface and the upper surface of the holding frame 7, respectively. ing. And
A closed space defined by the heat ray absorption filter 4, the far-ultraviolet ray cut filter 3, and the holding frame 7 serves as a ventilation passage 10 for cooling air. Other configurations are the same as those of the embodiment of the invention of claim 2 shown in FIG.

2 and 3, when the blower 8 is actuated and the lamp 1 is turned on, the ultraviolet light of about 365 nm among the light emitted from the lamp 1 passes through the far ultraviolet cut filter 3 and the heat ray absorption filter 4. Then, the liquid crystal display element L is irradiated and the adhesive S is cured. At this time, the light of 330 nm or less is emitted by the far-ultraviolet cut filter 3.
The heat ray absorption filter 4 does not deteriorate in characteristics because it is removed or attenuated by the heat ray absorption filter 4. Also, since the light having a long wavelength of 750 nm or more is removed or attenuated by the heat ray absorption filter 4, the liquid crystal display element L has a long wavelength. This is the same as the embodiment of the invention of claim 1 shown in FIG. 1 in that it is possible to prevent the “deviation” between the two liquid crystal substrates P1 and P2 due to the difference in the amount of thermal expansion, since it does not absorb the above light and does not heat up. is there.

Then, the cooling air sent from the blower 8 cools the heat ray absorption filter 4 which has absorbed long-wavelength light and has risen in temperature, so that almost no radiant heat is emitted from the heat ray absorption filter 4 and the object to be irradiated is radiated. That is, a great effect can be obtained in preventing the temperature rise of the liquid crystal display element L. By the way,
, The input of the lamp 1 is 200 W, the distance between the lower liquid crystal substrate P2 and the quartz plate 5 is 550 mm, and the liquid crystal substrate P2 is
Is 370 × 470 mm and a color filter is provided on the liquid crystal substrate P2, if the cooling air volume is 3.5 m ³ / min, then the two liquid crystal substrates P1,
The temperature difference of P2 is about 0.9 to 1.3 deg, and the “deviation” between the two liquid crystal substrates P1 and P2 is 2 to 3 μm or less, which is a practical problem even when bonding high-definition liquid crystal display elements. It turns out that there is no. Further, since the cooling air is discharged to the outside through the ventilation passage 10 in the closed space, the cooling air does not disturb the flow of clean air that is set in the manufacturing environment in advance, and the clean environment is maintained. Then, the light irradiation process can be performed.

In the embodiment of the invention of claim 2 shown in FIG. 2, since a plurality of heat ray absorbing filters 4 are arranged without being fixed to each other, when the heat ray absorbing filter 4 absorbs long wavelength light and rises in temperature. The thermal expansion can be absorbed by the minute gap generated between the heat ray absorption filters 4, and there is an advantage that troubles such as deformation and damage due to the heat expansion of the heat ray absorption filter 4 can be prevented. In addition, the heat ray absorption filter 4
In the embodiment of the invention of claim 3 shown in FIG. 3, the lower surface on which the light of the lamp 1 is incident (the surface on the side of the lamp 1) is heated by cooling air. Since it is cooled, there is an advantage that the heat ray absorption filter 4 can be efficiently cooled.

In the above embodiment, the object to be irradiated is the liquid crystal display element L in which the two liquid crystal substrates P1 and P2 are bonded together. However, for example, a protective film curing process for an optical disc or a drying process for printing a film is performed. As described above, although the two plate-like objects are not attached to each other, the present invention can be effectively applied even when the object to be irradiated absorbs long-wavelength light and rises in temperature during the light irradiation process. Can be applied.

[0029]

As described above, the light of the lamp is 3
Since a far-ultraviolet ray cut filter that removes or attenuates light having a wavelength of 30 nm or less and a heat ray absorption filter that removes or attenuates light having a wavelength of 750 nm or more is transmitted in this order to the object to be irradiated, the heat ray absorbing filter It is possible to effectively irradiate the irradiation target with ultraviolet rays in the vicinity of 365 nm for a long time without causing the characteristic deterioration, and to prevent the irradiation target from absorbing light having a long wavelength and raising the temperature. Further, since the heat ray absorption filter is cooled by the cooling air flowing through the ventilation passage which is a closed space, it is possible to prevent the temperature rise of the heat ray absorption filter which absorbs the light of long wavelength, and to raise the irradiated object due to the radiation heat of the heat ray absorption filter. A great effect can be obtained in preventing temperature. Therefore, the present invention can be effectively applied to a light irradiation process although the defect rate increases as the temperature of the irradiation target increases, such as two liquid crystal substrates in which the irradiation target is bonded with an ultraviolet curable adhesive. You can

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the invention of claim 1.

FIG. 2 is an explanatory diagram of an embodiment of the invention of claim 2;

FIG. 3 is an explanatory diagram of an embodiment of the invention of claim 3;

FIG. 4 is a spectral radiant flux diagram of a lamp.

FIG. 5 is a spectral radiant flux diagram of light transmitted through a far-ultraviolet ray cut filter.

FIG. 6 is a spectral radiant flux diagram of light transmitted through a far ultraviolet ray cut filter and a heat ray absorption filter.

FIG. 7 is an explanatory diagram of characteristic deterioration of the heat ray absorption filter.

[Explanation of symbols]

1 lamp 2 mirror 3 Deep UV cut filter 4 Heat ray absorption filter 5 Quartz plate 6 Quartz plate 7 holding frame 71 Air inlet 72 Exhaust port 8 Blower 9 ducts 10 Ventilation path L liquid crystal display element P1, P2 liquid crystal substrate S adhesive

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-11-254540 (JP, A) JP-A-8-114787 (JP, A) JP-A-9-185071 (JP, A) JP-A-8- 146436 (JP, A) JP-A-6-144890 (JP, A) JP-A-9-258026 (JP, A) JP-A-8-101395 (JP, A) JP-A-61-219932 (JP, A) JP-A-8-211396 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/13-1/141

Claims (5)

(57) [Claims] 1. A light irradiation device for irradiating an object to which a substance that causes a photochemical reaction is applied with ultraviolet rays to react the substance that causes the photochemical reaction, a light source section for irradiating light including ultraviolet rays, and 330 nm or less. A far ultraviolet cut filter for removing or attenuating light having a wavelength of 750 nm and a heat ray absorbing filter for removing or attenuating light having a wavelength of 750 nm or more. An optical processing device, characterized in that it is transmitted through an absorption filter and irradiated onto an object to be irradiated. 2. The light according to claim 1, wherein a quartz plate is arranged on the object side of the heat ray absorbing filter, and a ventilation passage through which cooling air flows is formed between the heat ray absorbing filter and the quartz plate. Processing equipment. 3. The optical processing device according to claim 1, wherein a ventilation passage through which cooling air flows is formed between the far ultraviolet ray cut filter and the heat ray absorption filter. 4. The substance that causes the photochemical reaction is an ultraviolet curable adhesive, and the object to be irradiated is two substrates.
Irradiate the adhesive applied between the two substrates with ultraviolet rays and
The optical processing apparatus according to any one of claims 1, 2, and 3, wherein a plurality of substrates are bonded together. 5. The optical processing apparatus according to claim 4, wherein the substrate is a liquid crystal substrate.