JP2017177519A - Method for joining member and optical element produced by the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for joining members suppressing the positional deviation between workpieces and further suppressing the making of bubbles in joined faces.SOLUTION: Provided is a method for joining the first member and the second member made of a resin, a glass or a crystal, in which at least either joined face of both the members is irradiated with ultraviolet light or plasma to cause surface modification, after the irradiation, the joined faces of both the members are contacted, both the members arranged in a vacuum state, and simultaneously, the joined faces are heated and pressurized.SELECTED DRAWING: Figure 1

Description

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

  2. Description of the Related Art Conventionally, an optical element in which a plurality of members having different optical characteristics are joined with an adhesive is widely known. However, there has been a problem that the strength of the optical element is lowered by the adhesive layer interposed between the members, or the optical properties of the members are impaired.

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

Japanese Patent No. 5152361

  However, in the work laminating method of Patent Document 1, the adhesion is small, ultraviolet light is irradiated onto the joint surfaces, the surfaces are laminated so that the surfaces come into contact with each other, and both works are added so that the joint surfaces are pressurized. Since a plurality of processes are performed in succession, such as heating and heating both workpieces, there is a possibility that bubbles may be mixed into the gaps between the workpieces.

  Moreover, when performing the above-mentioned plurality of steps, it is necessary to move the workpiece into each apparatus, and the positions of the workpieces may be shifted.

  The present invention has been made in view of the above situation, and when directly joining members without using an adhesive, the positions of the members are prevented from shifting during a plurality of steps, and the joining surface is also provided. It aims at providing the joining method of the member which suppresses a bubble entering.

  By performing heating and pressurization of both joining members under vacuum, the present inventors can improve the adhesion between the members, reduce the air bubbles mixed between the members, and the plurality of members with high accuracy. The present inventors have found that the alignment can be performed and have completed the present invention.

  That is, the invention described in claim 1 is a method of bonding the first member and the second member made of resin, glass, or quartz, and irradiates at least one of the bonding surfaces of both members with ultraviolet rays or plasma. This is a method of joining members in which the joint surfaces of both members are brought into contact with each other after irradiation, both members are placed in a vacuum state, and the joint surfaces are heated and pressurized at the same time.

  Invention of Claim 2 is a joining method of Claim 1, It is a joining method of the member whose wavelength of an ultraviolet-ray is 200 nm or less.

  Invention of Claim 3 is a joining method of Claim 1, It is a joining method of the member whose heating temperature is 50-150 degreeC.

  Invention of Claim 4 is a joining method of Claim 1, The joining method of the member whose applied pressure is 1-10 Mpa.

  The invention according to claim 5 is an optical element in which the first member and the second member made of resin, glass, or quartz are joined by the joining method according to any one of claims 1 to 4.

  According to the bonding method of the present invention, since at least one surface of the bonding surfaces of the first member and the second member is activated by ultraviolet rays or plasma, a direct chemical bond is formed between the bonding surfaces of both members. It is formed. For this reason, both members can be joined without interposing an adhesive layer between both members, and optical characteristics are prevented from being damaged by the adhesive layer. Moreover, since a heating and pressurizing process is performed under vacuum, it is suppressed that a bubble enters into a joining surface. Furthermore, since the heating and pressurizing steps are performed at the same time, the positions of the members are prevented from shifting.

It is a schematic diagram which shows the surface treatment process and state change of the member to join. It is a schematic diagram which shows the process of joining a member. It is a schematic diagram which shows the state change of the member arrange | positioned in a vacuum and heated and pressurized. It is a schematic diagram which shows the state change of each member of the same kind / different kind combination arrange | positioned in a vacuum and heated and pressurized. It is a schematic diagram which shows various joining states.

  The present invention is a method for bonding a first member and a second member made of resin, glass, or quartz, and irradiates at least one of the bonding surfaces with ultraviolet rays or plasma to perform surface modification. After the light irradiation, the bonding surfaces of both members are brought into contact with each other, both members are placed in a vacuum state, and the contact surfaces are heated and pressurized at the same time to produce an optical element. Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

(First member and second member to be joined, joined optical element)
As the first member and the second member, for example, the same kind of crystal and crystal, glass and glass, resin and resin may be joined, or different kinds of 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. Panel backlight, projector optical system, mobile phone liquid crystal panel, organic EL panel, solar cell panel, automotive fuel cell molding mold release agent pasting, lens molding mold release agent pasting Widely applied. FIG. 4A shows a schematic diagram when the optical element is film 1 and glass 2, FIG. 4B shows film 1a and film 1b, and FIG. 4C shows a case where glass 2a and glass 2b are joined together.

  FIG. 1 illustrates production of an optical element by bonding a film 1 and glass 2. First, a film 1 and a glass 2 that are optical elements are prepared. The material of the film 1 includes polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polyester, polymethyl methacrylate resin (PMMA), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), and cellulose acetate. Examples thereof include a polymer, a copolymer of polycarbonate (PC) and polystyrene (PS), and a copolymer of polymethyl methacrylate resin (PMMA) and polystyrene (PS). Specifically, COP includes Apel (registered trademark) manufactured by Mitsui Chemicals, ZEONOR (registered trademark) manufactured by Nippon Zeon, and Arton manufactured by JSR. Among these, the optical element is produced by bonding the film 2 made of the same material or different material and the glass 2. In the case of the embodiment of the present invention, for example, the film 1 made of polycarbonate (PC) and the glass 2 are bonded.

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

(Hydrophilic treatment (surface modification) process)
In a preferred embodiment of the present invention, at least one of a first member and a second member formed of any one of glass, resin, and quartz selected for producing the optical element as described above. Hydrophilic treatment (surface modification) is performed so that hydroxyl groups are present on the surface of the member. The surface to be modified is preferably a member with 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. The ultraviolet light is an excimer laser, plasma, or the like.

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

  The same surface modification can be performed also when the surface of the member is irradiated with plasma. For example, when the plasma generated by the atmospheric pressure plasma generator is irradiated, the surface is hydrophilized (surface modification). Is possible.

  By the ultraviolet irradiation or plasma irradiation as described above, oxygen in the air and ozone generated from the oxygen by irradiation act on the ultraviolet light 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, similarly to the film 1, the surface of the glass 2 may be irradiated with ultraviolet rays or plasma to modify the surface, or either one of the surfaces to which the film 1 or the glass 2 is bonded. May only be irradiated. Furthermore, as shown in FIG. 4, the same applies to the case where the films 1 and 2 are joined together.

(Heating / pressurizing process)
Thereafter, after the surfaces of two members formed of glass, resin, or quartz whose surfaces are modified are brought into close contact with each other, as shown in FIG. 2, this is made of a flat plate in a vacuum state. Arranged between the pressure members 4 and 5. As the pressure member, a metal flat plate with high surface accuracy or a member with high surface accuracy and elasticity can be selected.

  The surfaces subjected to the surface treatment are brought into contact with each other and placed between the pressure members in a vacuum to perform heating and pressure treatment. 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 applied pressure is effectively in the range of 1 to 10 MPa, and the most desirable applied pressure is about 2 MPa. The treatment time for heating and pressurizing is effective 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 FIG. 3, the surfaces of the two members are bonded by covalent bonding via oxygen on the surfaces as water is desorbed. Alternatively, as illustrated in FIG. 5, bonding is performed by hydrogen bonding between hydroxyl groups, or bonding is performed in a state where a covalent bond and a hydrogen bond are mixed. That is, the surfaces of the two members are directly joined without an adhesive layer or adhesive film made of an adhesive.

(Other)
The method of the present invention can be employed not only for polycarbonate film and glass but also for bonding films, glasses, or different types of films.
Other suitable examples of the combination of members to be joined include the following.
(A) Bonding of Resin Film and Glass Substrate (b) Bonding of Resin Film and Quartz Substrate Bonding of the resin film and the glass substrate is applied when adjusting the thickness of the optical element of the film. For example, the film itself is about 0.05 mm, but if a 0.5 mm glass substrate is bonded, it becomes 0.55 mm, and rigidity is also obtained. The optical element is a retardation plate or a polarizing plate. It is also used for liquid crystal panels, panel / black light joining members, projector optical systems, mobile phone liquid crystal panels, organic EL panels, solar cell panels, and the like.

  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 diffractive function by bonding to a retardation film.

  If the quartz substrate is a retardation plate, the resin retardation film and the quartz substrate can be bonded to each other in the same manner as the resin retardation film.

  In the case of bonding between quartz substrates, a retardation plate having high light resistance to laser light having a BD wavelength can be produced.

  In other words, a retardation plate using an organic material as a member, such as a retardation plate using a resin retardation film, or a retardation plate obtained by bonding a quartz retardation plate with an adhesive or an adhesive, is a BD wavelength. Although there is a concern that the organic material portion may be deteriorated by the irradiation of the laser beam, according to the manufacturing method of the present invention, it is possible to manufacture a quartz phase difference plate that is not deteriorated by the irradiation of the laser beam having the BD wavelength. .

(Effect of the present invention)
The present invention provides a method for manufacturing an optical element that can bond two members while maintaining transmittance and moisture resistance without using an adhesive, a bonding film, and the like, and an optical device manufactured using the method. An element can be provided. For this reason, the joint between the first member and the second member is characterized in that there is no adhesive layer seen when an adhesive or a pressure-sensitive adhesive is used and no distortion occurs.

  In addition, compared to the conventional bonding method in which a plurality of steps are sequentially performed, since heating and pressurization are simultaneously performed under vacuum, mixing of bubbles contained between members can be reduced, and the adhesion is improved several times. High-precision alignment between members can be performed.

1, 1a, 1b: film 2, 2a, 2b: glass 3: joined body (optical element)
4, 5: Pressurizing member (flat plate)

Claims (5)

A method of joining a first member and a second member made of resin, glass or crystal,
Irradiate at least one of the joint surfaces of both members with ultraviolet rays or plasma to modify the surface,
After the irradiation, the joining surfaces of both members are brought into contact with each other,
A method for joining members, characterized in that both members are placed in a vacuum state, and at the same time, the joining surfaces are heated and pressurized.   The method for bonding members according to claim 1, wherein the wavelength of the ultraviolet light is 200 nm or less.   The said heating temperature is 50-150 degreeC, The joining method of the member of Claim 1 characterized by the above-mentioned.   The method of joining members according to claim 1, wherein the pressure is 1 to 10 MPa.   The optical element by which the 1st member and 2nd member which consist of resin, glass, or a crystal | crystallization were joined by the joining method in any one of Claims 1-4.

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