JP6770816B2 - Method of joining members and optical elements manufactured by that method - Google Patents

Description

The present invention relates to, for example, an optical element in which different or similar members selected from resin, glass and quartz are bonded without having an adhesive layer, and a bonding method thereof.

Conventionally, an optical element in which a plurality of members having different optical characteristics are bonded with an adhesive has been widely known. However, there are problems that the strength of the optical element is lowered by the adhesive layer interposed between the members and the optical characteristics of the members are impaired.

On the other hand, as shown in Patent Document 1, it is a method of bonding the first and second workpieces made of resin and resin or resin and glass to each other, and ultraviolet light is applied to at least one of the surfaces to which both workpieces are bonded. After irradiating with light, laminating the above-mentioned bonded surfaces of both works so as to contact each other, pressurizing both works so that the contact surfaces are pressurized, and after releasing the pressurization, both works are pressed. A method of bonding workpieces to be heated is known. According to this method, both members can be directly joined without using an adhesive.

Japanese Patent No. 5152361 Japanese Unexamined Patent Publication No. 2000-21204

However, in the work bonding method of Patent Document 1, the adhesion is small, the joint surface is irradiated with ultraviolet light, the surfaces are laminated so as to be in contact with each other, and both works are added so that the joint surface is pressurized. Since a plurality of steps are continuously performed such as pressing and heating both works, there is a possibility that air bubbles may be mixed in the gaps between the works.

Further, when performing the above-mentioned plurality of steps, it is necessary to move the workpieces into the respective devices, and the positions of the workpieces may be displaced from each other.

By the way, conventionally, trimethylglycine, which is a kind of betaine-structured single molecule, has been used as an absorbent for diapers and as a moisturizing ingredient for cosmetic packs as described in paragraph 0046 of Patent Document 2. .. As a result of diligent research by the present inventors, it has been found that this betaine-structured single molecule can be bonded to a large number of substances such as resin, glass, and metal.

The present invention has been made in view of the above situation, and is a joining method in which members are directly joined without using an adhesive, and the positions of the members are suppressed from being displaced during a plurality of steps. Further, it is an object of the present invention to provide a joining method of a member for suppressing the entry of air bubbles into the joining surface.

The present inventors apply a betaine-structured single molecule to a surface-modified film, glass, etc., and bond them by placing them in an environment of optimum atmospheric pressure (vacuum degree), temperature, pressure, etc., and various optical elements. Was found to produce. In addition, by heating and pressurizing both joint members under vacuum, the adhesion between the members can be improved, air bubbles mixed between the members can be reduced, and a plurality of members can be aligned with high accuracy. We have found that we can do this, and have completed the present invention.

That is, the invention according to claim 1 is a method of joining a first member made of resin, glass or quartz and a second member made of resin, glass or quartz , and at least one of the joining surfaces of both members. Is surface-modified by irradiating with ultraviolet rays or plasma, and after irradiation, a betaine structure single molecule is placed between both members, the joint surfaces of both members are brought into contact with each other, and the joint surfaces of both members are heated and pressurized. It is a method of joining members characterized by.

The invention according to claim 2 is a method for joining members in which the joining surface is heated and pressurized in a vacuum in the joining method according to claim 1.

In the bonding method according to claim 1, the invention according to claim 3 has a betaine structure single molecule, which is commonly known as glycochol betaine, α-arrain, lolamin AMB-13, lubrin C, abromin, or glycine. Betaine, trimethylglycol, oxyneurine, oxyneurin, glycine Betaine, lysine, trimethylglycine, at least one selected from the system name, 2- (trimethylaminio) acetate anion, N, N-dimethyl-N- (Carboxyrate Methyl) Methanaminium, trimethylaminioacetate, N, N, N-trimethylaminioacetate, Carboxyratomethyltrimethylaminium, Carboxyrat-N, N, N-trimethylmethaneaminium, N, N, N-trimethylcarboxyrat methaneaminium, (carboxyrat methyl) trimethyl aminium, N, N-dimethyl-N-carboxyrat methyl methane aminium, α-carboxyrat-N, N, N-trimethyl methane aminium , 2-Oxo-2-oxyrat-N, N, N-trimethylethaneaminium, N, N, N-trimethyl-2-oxylat-2-oxoetaminium, (trimethylaminio) acetate anion, (trimethylami Nio) A method for joining at least one member selected from acetate, carboxylatomethyltrimethylammonium, and (2-oxo-2-oxylatethyl) trimethylaminium.

The invention according to claim 4 is the joining method for members having an ultraviolet wavelength of 200 nm or less in the joining method according to claim 1.

The invention according to claim 5 is a method for joining members having a heating temperature of 50 to 150 ° C. in the joining method according to claim 1.

The invention according to claim 6 is a method for joining members having a pressing force of 1 to 10 MPa in the joining method according to claim 1.

According to the joining method of the present invention, at least one surface of the joining surface of the first member and the second member is activated by ultraviolet rays or plasma, so that the betaine structure single molecule and the member to be subsequently arranged A direct chemical structure is formed between them. As a result, bonds are formed between both members via a betaine-structured single molecule. Therefore, both members can be joined without the need for an adhesive layer between the two members, and it is possible to prevent the adhesive layer from impairing the optical characteristics. Further, when the heating and pressurizing steps are performed under vacuum, air bubbles are suppressed from entering the joint surface. Further, since the heating and pressurizing steps are performed at the same time, it is possible to prevent the members from being displaced from each other.

It is a schematic diagram which shows the surface treatment process and the state change of the member to be joined. It is a schematic diagram which shows the state which the betaine structure single molecule is arranged between both members. It is a schematic diagram which shows the process of joining a member. It is a schematic diagram which shows various bonding states.

The present invention is a method of joining a first member and a second member made of resin, glass or quartz, and irradiating at least one joining surface of these members with ultraviolet rays or plasma to modify the surface. After irradiation with light, a betaine-structured single molecule is placed on one surface by coating, the joint surfaces of both members are brought into contact with each other, and the contact surfaces are heated and pressurized to produce an optical element. However, in carrying out the present invention, a specific embodiment thereof will be described in detail with reference to the drawings.

(First member and second member to be joined, optical element to be joined)
As the first member and the second member, the same type may be joined, for example, crystal and crystal, glass and glass, resin and resin, or different materials may be selected from crystal, glass and resin. It may be joined. Specific examples of the optical element composed of the first member and the second member include a lens, a prism, a wave plate used in a DVD or blue laser reader, a polarizing plate, a liquid crystal panel, and a liquid crystal display. Panel backlight, projector optical system, mobile phone liquid crystal panel, organic EL panel, solar cell panel, automobile fuel cell molding mold release agent pasting, lens molding mold release agent pasting Widely applied, such as attaching. FIG. 4A shows a schematic diagram in which the optical elements are film 1 and glass 2, (b) is film 1a and film 1b, and FIG. 4C is a schematic diagram in which glass 2a and glass 2b are bonded to each other.

FIG. 1 describes the production of an optical element by joining the film 1 and the glass 2. First, a film 1 and a glass 2 to be optical elements are prepared. The material of the film 1 is a combination of polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polyester, polymethyl methacrylate resin (PMMA), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), and cellulose acetate. There are polymers, copolymers of polycarbonate (PC) and polystyrene (PS), copolymers of polymethyl methacrylate resin (PMMA) and polystyrene (PS), and the like. Specifically, COP includes Apel (registered trademark) manufactured by Mitsui Chemicals, Zeonoa (registered trademark) manufactured by Zeon Corporation, and Arton manufactured by JSR. Of these, an optical element is manufactured by joining a film 1 made of the same material or a different material to a glass 2. In the case of the embodiment of the present invention, for example, a film 1 made of polycarbonate (PC) and a glass 2 are joined.

As the glass 2, a base material having a high flatness that has been mirror-polished or optically polished is used.

(Hydrophilic treatment (surface modification) process)
In one preferred embodiment of the present invention, at least one of a first member and a second member made of any of glass, resin, or quartz selected for producing the optical element as described above. Hydrophilization treatment (surface modification) is performed so that hydroxyl groups are present on the surface of the member. It is desirable that the surface to be surface-modified is a member having a high flatness.

First, in the case of the embodiment of the present invention, as shown in FIG. 1, a surface modification treatment is performed so as to make the surface of the film 1 made of polycarbonate hydrophilic. As a preferred method, the surface is irradiated with ultraviolet rays. Ultraviolet rays include excimer lasers and plasma.

Particularly preferable ultraviolet irradiation conditions are described. As the light source, light in a wavelength range of 200 nm or less is used, and an excimer laser or an excimer lamp having a emission line of 172 nm is preferable, but a low-pressure mercury lamp, a xenon lamp, or a deuterium lamp is used. be able to. Further, since the light may be 200 nm or less, a method of irradiating an electron beam of about several nm to several tens of nm may be used. For example, it may be an electron beam of about 5 nm to 90 nm. The illuminance is preferably 10 mW / cm ² , and irradiation is performed for at least 10 seconds, most preferably about 30 seconds.

Further, the same surface modification can be performed when the surface of the member is irradiated with plasma. For example, when the surface is irradiated with plasma generated by an atmospheric pressure plasma generator, the surface hydrophilization treatment (surface modification) is performed. It is possible.

By irradiating with ultraviolet rays or plasma as described above, oxygen in the air and ozone generated from oxygen by irradiation act with ultraviolet rays or plasma to generate active oxygen. This active oxygen modifies the surface of the film 1. As a result, the film 1 has a hydroxyl group as shown in FIG. 1 and has a surface state suitable for bonding.

As shown in FIG. 1, the surface of the glass 2 may be irradiated with ultraviolet rays or plasma to modify the surface as in the case of the film 1, or either the film 1 or the glass 2 is bonded. You may irradiate only. Further, as shown in FIG. 4, the same applies to the case where the films 1 and the glasses 2 are joined to each other.

(Arrangement of betaine structure monatomic gas)
Next, after surface modification of at least one of the joint surfaces of the first member and the second member, a betaine structure single molecule is arranged between the two members. A betaine-structured single molecule has positive and negative charges in non-adjacent positions within the same molecule, and the atom with positive charge does not have a dissociable hydrogen atom bonded (quaternary ammonium, sulfonium, phosphonium). It is a general term for compounds (intramolecular salts) that do not have an electric charge as a whole molecule. It is a substance that is widely present in plants and marine products in nature, and is used as a moisturizer for food additives and cosmetics. It is used. The trivial name have been collectively referred to as betaine, representative compounds, trimethyl glycine represented by the chemical formula C ₅ H ₁₁ NO _2, glycine betaine are known. The structural formula is as follows.

Others used as the betaine structure single molecule of the present invention include glycocholic betaine, α-arlein, lolamin AMB-13, lublin C, abromin, glycylbetaine, trimethylglycol, oxyneurine, etc. Examples thereof include oxyneurin, glycine betaine, lysine and trimethylglycine.

In the system name, 2- (trimethylaminio) acetate anion, N, N-dimethyl-N- (carboxyratmethyl) methaneaminium, trimethylaminioacetate, N, N, N-trimethylaminioacetate , Carboxylamethyl trimethylaminium, Carboxyrate-N, N, N-trimethylmethaneaminium, N, N, N-trimethylcarboxylatamethaneaminium, (Carboxylamethyl) trimethylaminium, N, N-dimethyl- N-carboxyrat Methyl Methane Aminium, α-Carboxyrat-N, N, N-trimethyl Methane Aminium, 2-oxo-2-Oxyrat-N, N, N-trimethylethane Aminium, N, N, N- Trimethyl-2-oxylat-2-oxoethaneaminium, (trimethylaminio) acetate anion, (trimethylaminio) acetate, carboxylatomethyltrimethylammonium, (2-oxo-2-oxylatethyl) trimethylaminium, etc. Can be mentioned.

As a method of arranging the betaine structure single molecule between the two members, a solution of betaine is prepared and the betaine structure is arranged in a wet manner by a known coating method. Specifically, a liquid in which trimethylglycine, which is a kind of betaine structure single molecule, is dissolved is prepared, and wet (solution coating method) such as dip coating method, solution coating method (immersion method), spin coating method, and bar coating method is used. ), Apply by brush coating method, etc. The betaine then forms a monolayer between the two members by removing the solvent.

In the examples of the present invention, specifically, as the betaine structure single molecule, a superhydrophilic coating agent manufactured by Osaka Organic Chemical Industry Co., Ltd., a hydrophilic coating agent manufactured by Nittobo Medical, and the like were used. Although the figure illustrates an example using trimethylglycine, the present invention is not limited to this example.

When trimethylglycine is placed on the glass 2 as shown in FIG. 2 (a) and the film 1 is brought into contact with the film 1, the oxygen group of trimethylglycine and the hydroxyl group of the glass are combined with ammonium nitrogen as shown in FIG. 2 (b). The hydroxyl groups of the film are bonded by hydrogen bonds to bond both members. Alternatively, depending on the bonding conditions (temperature, pressure) described later, trimethylglycine reacts with the hydroxyl group on the surface of the film or glass as shown in FIG. 2C, and the film or glass is bonded by a covalent bond via oxygen.

(Heating / pressurizing process)
After that, the surfaces were modified and the surfaces of the two members formed of glass, resin, or quartz on which the betaine-structured single molecule was arranged were brought into close contact with each other, and then this was applied as shown in FIG. It is arranged between the pressure members 4 and 5 made of a flat plate. As the pressurizing member, a metal flat plate having high surface accuracy or a member having high surface accuracy and elasticity can be selected.

The surface-treated surfaces are brought into contact with each other, placed between the pressurizing members under atmospheric pressure, and heated and pressurized. At this time, the heating temperature is effectively in the range of about 50 ° C. to 150 ° C., and the most desirable temperature is about 80 ° C. The pressing force is effective in the range of 1 to 10 MPa, and the most desirable pressing force is about 2 MPa. The treatment time for the heating and pressurizing treatment is effectively in the range of 30 seconds to 300 seconds, and the most desirable treatment time is about 100 seconds.

By this heating and pressurizing treatment, as shown in FIGS. 4A to 4C, the surfaces of the two members are bonded by forming a hydrogen bond between the single molecule having a betaine structure and the hydroxyl group on the surface of the member. (B) A single molecule having a betaine structure reacts with a hydroxyl group on the surface of a member to form a covalent bond via oxygen, or (c) a bond is formed in a state where a covalent bond and a hydrogen bond are mixed. .. That is, the surfaces of the two members are directly bonded without an adhesive layer or film of adhesive.

In the present invention, it is preferable that the heating and pressurizing steps are performed under vacuum. In that case, after the surfaces of two members formed of glass, resin, or quartz, whose surfaces have been modified and betaine-structured single molecules are arranged, are brought into close contact with each other, they consist of a flat plate under vacuum. It is arranged between the pressurizing members 4 and 5. The preferable heating conditions, temperature conditions, and treatment time under vacuum are the same as in the same step under normal pressure.

(Other)
The method of the present invention can be adopted not only for bonding polycarbonate films and glass, but also for bonding films to each other, between glasses, or to different types of films.
Other suitable examples of combinations of members to be joined include the following.
(A) Bonding of resin film and glass substrate (b) Bonding of resin film and crystal substrate Bonding of resin film and glass substrate is applied when adjusting the thickness of the optical element of the film. For example, the film alone is about 0.05 mm, but if a 0.5 mm glass substrate is joined, it becomes 0.55 mm, and rigidity can be obtained. The optical element is a retardation plate or a polarizing plate. It is also used in liquid crystal panels, joint members between panels and black lights, optical systems for projectors, liquid crystal panels for mobile phones, organic EL panels, solar cell panels, and the like.

Further, when the glass substrate to be bonded is a diffraction grating, it is possible to manufacture a composite optical element having both a polarizing function and a diffraction function by bonding with a retardation film.

In the bonding of the resin retardation film and the crystal substrate, if the crystal substrate is a retardation plate, the wide band of the retardation plate can be widened by laminating in the same manner as the bonding of the resin retardation film.

In the case of joining crystal substrates to each other, it is possible to manufacture a retardation plate having high light resistance to laser light having a BD wavelength.

That is, a retardation plate using an organic material as a member, such as a retardation plate using a resin retardation film or a retardation plate made by laminating a crystal retardation plate with an adhesive or an adhesive material, has a BD wavelength. Although there is a concern that the organic material portion may be deteriorated by the irradiation of the laser beam of the above, according to the manufacturing method of the present invention, it is possible to manufacture a crystal retardation plate which is not concerned about the deterioration by the irradiation of the laser beam of the BD wavelength. ..

(Effect of the present invention)
The present invention is a method for manufacturing an optical element capable of joining two members while maintaining transmittance and moisture resistance without using an adhesive, a bonding film, or the like, and an optical manufactured using the method. The element can be provided. Compared with the conventional technique using an adhesive layer having a macro thickness, betaine is arranged as a single molecule, so that it has almost no adverse effect on the optical properties, and the first member and the second member are not affected. The joint portion is characterized in that, in appearance, there is no adhesive layer that is seen when an adhesive or an adhesive material is used, and distortion or the like does not occur.

In addition, when a betaine structure single molecule such as trimethylglycine is interposed, any substance such as glass and metal, film and metal, and metal can be bonded in addition to resin to glass, glass to glass, and resin to glass. it can.

As a result, when an optical element to which a film is attached with an adhesive is used in the ultraviolet region, the adhesive undergoes a chemical change, but when a betaine structure single molecule is used, it also changes with ultraviolet rays. You can work without any trouble. Further, even when it is used for a liquid crystal panel or the like, the image, characters, etc. displayed by the backlight can be clearly displayed without being distorted. The same applies to the organic EL panel, and images, characters, and the like can be clearly displayed without being distorted. In particular, even when displaying a three-dimensional image, the depth can be clearly displayed, so that an object that is exactly the same as an object that is naturally seen without any discomfort is displayed on the screen.

Further, in the mode in which heating and pressurization are performed under vacuum, the mixing of air bubbles contained between the members can be reduced as compared with the case where the mixing is performed under atmospheric pressure, the adhesion is improved several times, and the positions of the members are highly accurate. You can make adjustments.

1: Film 2: Glass 3: Joined body (optical element)
4, 5: Pressurizing member (flat plate)

Claims (6)

A method of joining a first member made of resin, glass or quartz and a second member made of resin, glass or quartz .
Irradiate at least one of the joint surfaces of both members with ultraviolet rays or plasma to modify the surface.
After the irradiation, a betaine-structured single molecule was placed between the two members.
The joint surfaces of both members are brought into contact with each other.
A method for joining members, which comprises heating and pressurizing the joint surfaces of both members. The method for joining members according to claim 1, wherein the joint surface is heated and pressurized in a vacuum. The betaine structure single molecule is
By trivial name, at least one selected from glycochol betaine, α-earlein, lolamin AMB-13, lublin C, abromin, glycylbetaine, trimethylglycol, oxyneurine, oxyneurin, glycine betaine, lysine, trimethylglycine. And
In the system name, 2- (trimethylaminio) acetate anion, N, N-dimethyl-N- (carboxyratmethyl) methaneaminium, trimethylaminioacetate, N, N, N-trimethylaminioacetate, carboxy Latomethyltrimethylaminium, Carboxyrate-N, N, N-trimethylmethaneaminium, N, N, N-trimethylcarboxylatamethaneaminium, (carboxylatomethyl) trimethylaminium, N, N-dimethyl-N- Carboxyrate Methylmethane Aminium, α-Carboxyrat-N, N, N-trimethylmethane Aminium, 2-oxo-2-oxylat-N, N, N-trimethylethaneaminium, N, N, N-trimethyl- Selected from 2-oxylat-2-oxoethaneaminium, (trimethylaminio) acetate anion, (trimethylaminio) acetate, carboxylatomethyltrimethylammonium, (2-oxo-2-oxylatethyl) trimethylaminium The method for joining members according to claim 1, wherein the number is at least one. The method for joining members according to claim 1, wherein the wavelength of the ultraviolet rays is 200 nm or less. The method for joining members according to claim 1, wherein the heating temperature is 50 to 150 ° C. The method for joining members according to claim 1, wherein the pressing force is 1 to 10 MPa.

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