JP5501918B2 - Optical element manufacturing method and optical element produced by the method - Google Patents

Description

  The present invention relates to an optical element manufacturing method and an optical element manufactured by the method, and for example, a birefringent material used as a retardation plate for an optical pickup and a manufacturing method of a holding substrate and a phase difference optical manufactured by the method The present invention relates to an optical element such as a diffraction element, a prism, and a lens.

  A birefringent material such as a retardation film or a quartz substrate is used as a retardation plate for an optical pickup.

  In addition, in an optical pickup that can share DVD (registered trademark) and CD (registered trademark) or Blu-ray Disc (registered trademark), when light of a plurality of wavelengths is used in the same optical system, an arbitrary phase difference is set. A retardation plate that is produced by laminating a plurality of birefringent materials and that functions at a plurality of wavelengths is used.

  Among the retardation plates used in this, for example, when a retardation film is bonded to a fixed substrate such as glass, it is known to use an adhesive or a pressure-sensitive adhesive as shown in Patent Document 1.

  Moreover, when joining retardation films in order to manufacture a laminated phase difference plate, using the joining technique as shown in patent document 2 is known.

Japanese Patent No. 3458895 JP 2001-277433 A

  In a phase difference plate for an optical pickup, for example, in the joining method described in Patent Document 1, transmission wavefront aberration characteristics required as a phase difference plate may be deteriorated due to uneven coating film thickness of the adhesive. Further, the light transmittance is also affected by the difference in refractive index between the retardation plate and the adhesive, and the transmittance is lowered.

  Furthermore, in a reliability test such as a humidity test, the adhesive may be peeled off and the quality may be deteriorated.

  Moreover, in the joining method as described in Patent Document 2, for example, there is a residual solvent in a manufactured product due to solvent welding using an organic solvent. Moreover, since an environmentally hazardous substance is used, such a method is not a preferable manufacturing method.

  The present invention provides an optical element manufacturing method and method capable of bonding two members while maintaining transmission wavefront aberration characteristics, transmittance, and moisture resistance without using an adhesive, a bonding film, or the like. An object of the present invention is to provide an optical element manufactured using the same.

  Examples of the solving means of the present invention are as follows.

(1) After applying hydrophilic treatment on the surface of any two substrates of glass, resin, or quartz so that a hydroxyl group exists, and bringing the treated surfaces of any two substrates of glass, resin, or quartz into close contact with each other A method for producing an optical element, comprising heating to 50 ° C. to 150 ° C. and pressurizing at a pressure of 1 to 10 MPa to produce an optical element by bonding without an adhesive and an adhesive film.

(2) In the method for manufacturing an optical element according to claim 1, the optical element in a state in which the processing surfaces of any two substrates of glass, resin, and quartz are in close contact with a base material having high flatness is placed. And pressurizing with a member having elasticity with a heat-resistant resin from the upper side of the optical element.

(3) The method of manufacturing an optical element, wherein the optical element is any one of a retardation plate, a diffraction element, a prism, and a lens.

(4) In the method of manufacturing an optical element according to any one of claims 1 to 3, the surface of any two substrates of glass, resin, and quartz is formed by covalent bonding or hydrogen bonding via oxygen on the surface. A method for manufacturing an optical element, wherein the optical element is bonded.

(5) After performing hydrophilic treatment on the surface of any two substrates of glass, resin, or quartz so that a hydroxyl group exists and bringing the treated surfaces of any two substrates of glass, resin, or quartz into close contact with each other An optical element characterized by being bonded without an adhesive or an adhesive film by heating to 50 ° C. to 150 ° C. and pressurizing at a pressure of 1 to 10 MPa.

(6) In the optical element according to claim 4, the substrate is mounted on a base material having high flatness in a state where the processing surfaces of any two substrates of glass, resin, and quartz are in close contact with each other, and heat resistance is applied from above. An optical element that is bonded by pressurizing with an elastic member made of a functional resin.

(7) The optical element according to any one of claims 4 to 6, wherein the optical element is any one of a retardation plate, a diffraction element, a prism, and a lens.

(8) In the optical element according to any one of claims 4 to 7, the surfaces of any two substrates of glass, resin, and quartz are joined by covalent bonding or hydrogen bonding via oxygen on the surface. An optical element.

  According to the present invention, a hydrophilic treatment is performed so that a hydroxyl group exists on the surface to which a member such as resin, glass, or quartz is bonded, the members are bonded to each other, and placed on a substrate having high flatness. The members can be joined together by applying pressure with a member having elasticity with a heat resistant resin.

  In the present invention, since no adhesive, pressure-sensitive adhesive, bonding film or the like is required, transmission wavefront aberration characteristics required as a retardation plate are deteriorated due to uneven coating thickness of adhesive or uneven thickness of adhesive. There is no.

  Regarding the light transmittance, when the same base material is bonded, there is no reduction in transmittance because there is no layer having a difference in refractive index compared to the case where an adhesive is used.

  Furthermore, even in a reliability test such as a humidity test, no peeling of the adhesive occurs and high quality can be maintained.

  Further, even when compared with a joining method by solvent welding using an organic solvent, according to the present invention, there is no fear of deterioration with time due to the residual solvent, and no environmentally hazardous substance is discharged.

  In addition, a retardation plate using an organic material as a member, such as a retardation plate using a resin retardation film or a quartz retardation plate bonded with an adhesive or an adhesive, is a BD wavelength laser beam. There is a concern that the organic material portion may be deteriorated by the irradiation, but there is no concern of such deterioration if the quartz phase difference plate is produced by the manufacturing method of the present invention.

Explanatory drawing of the state of the base material by which the surface treatment was carried out. Explanatory drawing of arrangement | positioning of each member at the time of pressurization. Explanatory drawing of the joined state after a heating and pressurization.

  In one preferred embodiment of the present invention, a hydrophilic treatment is performed so that hydroxyl groups are present on the surfaces of two substrates formed of glass, resin, or quartz, and then glass, resin, or quartz is used. After the surfaces of the two substrates formed in any one of them are brought into close contact with each other, they are placed on a substrate having high flatness, and are sandwiched between members having elasticity with a heat resistant resin from above, and are kept at 50 ° C. to 150 ° C. By heating and pressurizing at a pressure of 1 to 10 MPa, the surfaces of the two substrates formed of any one of glass, resin, and quartz are bonded by covalent bonding or hydrogen bonding via oxygen on the surface. That is, the surfaces of the two substrates are bonded without an adhesive or an adhesive film.

  In addition, the optical element of the present invention was formed of any one of glass, resin, and quartz after applying a hydrophilic treatment on the surface of any two substrates of glass, resin, and quartz so that a hydroxyl group exists. After the surfaces of the two substrates are brought into close contact with each other, they are placed on a substrate having high flatness, sandwiched between members having elasticity with a heat-resistant resin from the upper side, heated to 50 ° C. to 150 ° C., and 1 to 10 MPa. It is joined without the adhesive and the adhesive film. As a result, the surfaces of the two substrates formed of any one of glass, resin, and quartz are joined by covalent bonds or hydrogen bonds via oxygen on the surfaces.

  In addition, the above-described optical element is preferably any one of a retardation plate, a diffraction element, a prism, and a lens.

Description of Illustrated Example A case where the optical element is a retardation plate, particularly a case where phase difference films (retardation plates) made of resin are bonded to each other will be described with reference to the drawings.

  Hereinafter, the production of the retardation optical element by joining the retardation films (retardation plates) will be described.

  Two retardation films 1 and 2 to be a retardation optical element are prepared.

  As materials for the retardation films 1 and 2, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polyester, polymethyl methacrylate resin (PMMA), polyvinyl alcohol (PVA), triacetyl cellulose (TAC), Examples thereof include a cellulose acetate copolymer, a polycarbonate (PC) and polystyrene (PS) copolymer, and a polymethyl methacrylate resin (PMMA) and polystyrene (PS) copolymer. Specifically, COP includes Apel (registered trademark) manufactured by Mitsui Chemicals, ZEONOR (registered trademark) manufactured by Nippon Zeon, and Arton manufactured by JSR.

  Among these, an optical element is produced as a retardation plate by bonding the retardation films 1 and 2 made of the same material or different materials.

  In the case of the present embodiment, for example, retardation films 1 and 2 made of polycarbonate (PC) are joined.

  First, a surface treatment is performed to make the surfaces of the retardation films 1 and 2 made of polycarbonate hydrophilic. As a preferred method, the surface is irradiated with ultraviolet rays. Particularly preferable ultraviolet irradiation conditions are as follows. Using light having a wavelength region of 200 nm or less, irradiation is performed at an illuminance of 10 mW / cm 2 for at least 10 seconds, and most desirably for about 30 seconds.

  By such ultraviolet irradiation, oxygen in the air and ozone generated from oxygen by the ultraviolet irradiation act on the ultraviolet rays to generate active oxygen. This active oxygen modifies the surfaces of the retardation films 1 and 2. As a result, the retardation films 1 and 2 are in a surface state suitable for bonding as shown in FIG.

  As an ultraviolet light source, an excimer lamp having an emission line of 172 nm is preferable, but a low-pressure mercury lamp, a xenon lamp, or a deuterium lamp can be used.

  Also, the same surface modification can be performed when the substrate surface is irradiated with plasma. For example, the surface can be made hydrophilic even when the plasma generated by the atmospheric pressure plasma generator is irradiated. .

  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.

  Next, the surfaces subjected to the surface treatment are brought into contact with each other, and heating and pressure treatment are performed. 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 arrangement of each member during pressurization is shown in FIG. The film 3 in which the surfaces subjected to the surface treatment are brought into contact with each other is sandwiched between the flat plates 4 and 5. The flat plate 4 is disposed below the film 3 and the flat plate 5 is disposed on the upper side to sandwich the film 3.

  The flat plate 4 uses a base material having high flatness such as a mirror-finished metal plate or an optically polished glass substrate. The flat plate 5 uses a heat-resistant rubber-like flat base material such as silicon rubber, and is uniformly pressed on the entire surface of the film 3 by the flat plate 5 from above the film 3 by a pressurizing mechanism (not shown). The flat plate 5 may be a heat-resistant resin and an elastic member in addition to the heat-insulating rubber-like flat base material.

  The processing time is effectively in the range of 30 to 300 seconds, and the most desirable processing time is about 100 seconds.

  By the above treatment, as shown in FIG. 3, covalent bonds or hydrogen bonds via oxygen are formed on the surfaces of the retardation films 1 and 2, and the retardation films 1 and 2 are firmly bonded to each other.

  The phase difference films 1 and 2 have the following features in appearance. That is, there is no adhesive layer observed when an adhesive or a pressure-sensitive adhesive is used, and no distortion occurs.

  The above-described method can be used not only for bonding polycarbonate films but also for bonding the above-described retardation films or different types of films.

  Other preferred examples of the combination of substrates to be joined include the following.

(A) Bonding of resin retardation film and glass substrate (b) Bonding of resin retardation film and crystal substrate For bonding of retardation film of resin and glass substrate, adjusting the thickness of the retardation film of the film Applies to For example, the retardation 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.

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. .

1, 2 retardation film 3 film 4, 5 flat plate

Claims (2)

When irradiating with ultraviolet rays or plasma, the surface of the retardation film made of two optical resins is irradiated with light having a wavelength range of 200 nm or less at an illuminance of about 10 mW / cm 2 for at least 10 seconds, and a hydroxyl group is present. hydrophilized to, then, the surface between the two retardation films, namely two hydrophilic treatment surface was between close contact, and a member having a high elasticity is high surface accuracy metal flat plate or surface accuracy In that state, they are hydrophilized in the form without an adhesive / adhesive film by heating them to 50-150 ° C. and pressurizing them at a pressure of 1-10 MPa . A method for producing a phase difference optical element, characterized by joining treated surfaces. Retardation optical element manufactured by the manufacturing method according to claim 1.

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