JP2009025501A - Wavelength plate with diffraction grating, and method of manufacturing wavelength plate with diffraction grating - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact and lightweight composite element of excellent environment resistant performance, by providing a diffraction grating directly on a resin phase difference plate, without using an adhesive. <P>SOLUTION: Irregular shapes are formed on a film resin surface by a nano-printing method, and the diffraction grating is formed directly on the film resin surface, in this wavelength plate with the diffraction grating. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an optical pickup device, a semiconductor exposure device, and a PDP / liquid crystal substrate used for reading / reproducing a recording medium such as a CD, a DVD (registered trademark), an HD-DVD (registered trademark), and a Blu-Ray Disc (registered trademark). The present invention relates to a wave plate with a diffraction grating and a method for manufacturing a wave plate with a diffraction grating used in an electron beam apparatus such as an exposure apparatus, an electron microscope, a surveying instrument, and an ophthalmic measurement optical apparatus.

  Conventionally, researches such as lightening and downsizing of an optical pickup (optical head) have been actively conducted.

  Of these, when diffracting / diffusing / separating light, etc., one optical element has been introduced into the optical path mainly for one purpose. A composite optical element in which a plurality of functions are integrated into one optical element has also been developed.

  For example, Patent Document 1 discloses a configuration in which a diffraction grating made of SiO 2 is formed on an intermediate layer laminated on one side of an anisotropic crystal plate made of quartz that functions as a wavelength plate, and the whole is integrated. Yes.

  Further, as a method for forming a diffraction grating, for example, in Patent Document 2, a photoresist pattern formed on a transparent substrate is exposed and developed, and a diffraction grating pattern is formed. A metal layer is formed by vacuum deposition, sputtering, etc., then the photoresist pattern and metal layer are removed, and a metal lattice pattern is formed on a transparent substrate by dry etching such as ion beam etching. Discloses a method of forming an etching part to a desired depth and removing a metal mask to form a diffraction grating.

  For example, Patent Document 3 discloses a wave plate having an optical diffraction element made of a birefringent optical crystal. In particular, FIG. 6 discloses a composite optical element in which a birefringent diffractive element and a quarter-wave plate are contained in the same package.

  Further, as described in claim 1 and claim 4 of Patent Document 4, the orthogonal polarization of incident light is converted to zero order by a periodic grating in which birefringent regions and isotropic regions are alternately arranged. In an optical head using a grating-type broadband polarization separation element that separates light into diffracted light, an optical head in which a quarter-wave plate is integrated with the broadband light separation element has been proposed. In paragraphs 0037 to 0038 of the specification of Patent Document 4, a quarter-wave plate is bonded and integrated on the isotropic overcoat layer of the polarization separation element, or on the glass substrate of the polarization separation element. It is disclosed that a quarter wave plate is attached and integrated to form a polarization separation element with a quarter wave plate.

  Patent Document 5 discloses a composite optical element in which a λ / 4 plate is integrated on a polarizing diffractive element in which an oriented thin film formed on a substrate is covered with an isotropic medium. .

  Patent Document 6 discloses a surface having a function equivalent to a quarter-wave plate made of a sub-wavelength structure as a fine periodic structure on one surface (the lower surface in FIG. 1) of a light-transmitting substrate made of glass or the like. The sub-wavelength structure constituting this surface is a structure formed with a size smaller than the wavelength of light used by the formation pitch (uneven pitch) using a fine processing technique such as a nano-processing technique. It is described that other cross-sectional shapes can be selected. Further, in paragraph 0029 of Patent Document 6, as a material constituting the subwavelength structure, a material such as SiNx or Si (preferably having a refractive index of 2.0 or more) can be appropriately selected. Are listed.

Further, for example, Patent Document 7, Paragraph 0083, and FIG. 12 disclose a composite functional optical member in which an aperture is formed on the outer peripheral portion on one side of a quarter-wave plate and a diffraction grating is formed in the center. ing.
JP 2004-101984, paragraph 0008, FIG. Japanese Patent No. 3852253, paragraphs 0036-0038, FIG. Japanese Patent No. 2616018, claims, page 3, left column, line 33 to page 37, line 37, FIG. Japanese Patent No. 3667984, claims, paragraphs 0038-0037, FIG. JP 11-31329 A, paragraph 0032, FIG. Japanese Patent Laying-Open No. 2005-77659, paragraphs 0027-0029, FIG. Japanese Patent Laid-Open No. 7-169062, paragraph 0083, FIG.

  However, conventional optical composite elements such as those disclosed in Patent Documents 3, 4, and 7 are manufactured by, for example, bonding a resin retardation plate to a glass diffraction grating with an adhesive. In this case, since the difference between the linear expansion coefficients of the two materials is large, there is a problem that the bonded portion peels off when used at a high temperature.

  Moreover, when integrating the diffraction grating manufactured as shown in Patent Document 2 with a wave plate, a resin such as an adhesive is required, and the difference in linear expansion coefficient between the two materials is large. When used under high temperature, there were problems such as peeling of the bonded part.

  Further, in the conventional composite optical elements as shown in Patent Documents 1 and 5, when a diffraction grating made of quartz, quartz, or an orientation thin film is bonded to a retardation plate, quartz, quartz, The adhesive part sometimes peeled off due to the difference in linear expansion coefficient between the oriented thin film and the adhesive.

  Furthermore, a general (conventional) UV curable resin has a large expansion coefficient and is bent, and when a diffraction grating is actually manufactured, the aspect ratio deteriorates, the diffraction performance deteriorates, the wavelength A shift will occur.

  For example, also in the invention of Patent Document 6, the sub-wavelength structure is formed on a light-transmitting substrate made of glass or the like by vapor deposition or adhesion, and as described above, the linear expansion between the sub-wavelength structure and the adhesive is performed. The bonded part sometimes peeled off due to the difference in coefficient.

  Therefore, in order to eliminate the above-mentioned problems, the present invention provides a composite element that is compact, lightweight, and has excellent environmental resistance performance, for example, by directly providing a diffraction grating on a resin retardation plate without using an adhesive. The purpose is to do.

  Examples of the solution means of the present invention for solving the above-described problems are as follows.

(1) A wave plate with a diffraction grating, which is directly formed on the surface of a film resin wave plate without using an adhesive.

(2) The above-mentioned wavelength plate with a diffraction grating, wherein a concavo-convex shape is formed on the surface of the film resin by a nanoimprint method, and the diffraction grating is directly provided on the surface of the film resin.

(3) The aforementioned wavelength plate with a diffraction grating, wherein the film resin has a reduced expansion coefficient.

(4) The aforementioned wavelength plate with a diffraction grating, wherein the film resin has a coefficient of expansion lowered by introduction of quartz nanoparticles.

(5) The aforementioned wavelength plate with a diffraction grating, wherein the film resin is made of a photo-curing resin, and a dye having wavelength selection is introduced into the photo-curing resin.

(6) The wave plate with a diffraction grating described above, wherein a convex shape is formed on the surface of the film resin with a high aspect ratio of 5 or less.

(7) A method for producing a wave plate with a diffraction grating, wherein a diffraction grating is directly formed on the surface of a wave plate made of a film resin without using an adhesive.

(8) The method for producing a wave plate with a diffraction grating as described above, wherein a concave and convex shape is formed on the surface of the film resin by a nanoimprint method, and the diffraction grating is directly formed on the surface of the film resin.

(9) The method for producing a wave plate with a diffraction grating as described above, wherein a film resin having a reduced expansion coefficient is used.

(10) The method for producing a wave plate with a diffraction grating as described above, wherein quartz nanoparticles are introduced to lower the expansion coefficient of the film resin.

(11) The method for producing a wave plate with a diffraction grating described above, wherein a photocurable resin is used as the film resin, and a dye having a wavelength selection is introduced into the photocurable resin.

(12) The above-mentioned diffraction, wherein a fluorine-based resin is used as a mold release material for mold mold release treatment, so that an antireflection coating or an antifouling coat is applied to the element at the time of mold release. Manufacturing method of wave plate with grating.

  The present invention can provide a composite element having a small size and light weight and excellent environmental resistance performance by providing a diffraction grating directly on a resin phase difference plate, for example, by a nanoimprint method without using an adhesive.

  Further, since the diffraction grating is formed directly on the surface of the wave plate made of film resin without using an adhesive, the bonded portion does not peel off due to the difference in the linear expansion coefficient of the adhesive.

  In addition, the expansion coefficient of the film resin can be reduced by introducing quartz nanoparticles or the like, and in this case, the thermal change is small and the production with stable performance becomes possible.

  In addition, when a fluorine-based resin is used as a mold release material for mold release treatment, an antireflection coating, a stain prevention coat, or the like can be applied to the element during mold release.

  Further, in the UV nanoimprint, if a dye having wavelength selection is introduced into the photocurable resin, a diffraction grating having wavelength selectivity can be produced.

  In the present invention, a concavo-convex shape is formed on the film resin surface, and a diffraction grating is formed directly on the film resin surface. For example, a diffraction grating is directly provided on a phase difference plate made of a film resin by a nanoimprint method. Preferably, a film resin having a reduced expansion coefficient is used. In particular, quartz nanoparticles are introduced to lower the expansion coefficient of the film resin.

  Moreover, it is preferable to use a photocurable resin as the film resin and introduce a dye having wavelength selection into the photocurable resin.

  Further, it is preferable to apply an antireflection coating or a stain prevention coating to the element at the time of mold release by using a fluorine-based resin as a mold release material for the mold release treatment.

  In the case of thermal nanoimprint, the mold to be used is preferably molded as shown below.

1 is a cross-sectional view of (A), using a technique such as lithography or laser ablation, die to form a fine uneven structure on the Si and SiO ₂ surface 1 (the matrix).

  The size of the mold 1 is, for example, about 1 mm to 100 mm on one side. In particular, when the laser ablation method is used, it is possible to perform ultrafine processing in which the aspect ratio of the convex mold 1a of the mold 1 is 5 or less, preferably about 5.

  When the convex mold 1a is formed by an ultra-sharp beam 2 such as a lithography electron beam or laser ablation laser beam, it is easy to perform ultrafine processing so that the aspect ratio of the convex mold 1a of the mold 1 is about 5. is there.

  In the concavo-convex microstructure, the convex mold 1a may be cylindrical or prismatic.

  Further, the convex mold 1a may have a lattice shape, a staggered shape, or a random structure.

  Preferably, the interval between the convex molds 1a is about several nm to 100 nm.

  As shown in FIG. 1B, a release film 3 is preferably formed on the surface of the mold 1 by coating.

  Furthermore, as shown in FIG. 1C, for example, a film resin constituting the wave plate 4 made of COP (cycloolefin polymer, cyclic polyolefin) resin having a thickness of 0.1 mm manufactured by Colorlink Japan, etc. Nanoimprint on the surface. Corresponding to the mold 1, an uneven fine structure is transferred on the surface of the film resin, and a convex mold 4 a is formed with a high aspect ratio of 5 or less. In that case, the uneven | corrugated fine structure is formed in the space | interval of the convex mold | type 4a about several nm-100 nm.

  The types of film resin to which the concavo-convex microstructure is transferred include polyamide (PA), nylon, polyacetal (POM), polycarbonate (PC), modified polyphenylene ether (m-PPE, modified PPE), and polybutylene in addition to the above-mentioned COP. Engineering plastics (abbreviated as engineering plastic for short) such as terephthalate (PBT), polyethylene terephthalate (PET), polyethylene terephthalate with glass resin (PET-G), glass fiber reinforced polyethylene terephthalate (GF-PET), polyethylene (PE) , High density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), polypropylene (PP), polyvinyl chloride (PVC), polyvinylidene chloride, polystyrene ( S), polyvinyl acetate (PVAc), Teflon (registered trademark), polytetrafluoroethylene, PTFE, ABS resin (acrylonitrile butadiene styrene resin), AS resin, acrylic resin (PMMA), and other thermoplastic resins such as , Phenolic resin (PF), epoxy resin (EP), melamine resin (MF), urea resin (urea resin, UF), unsaturated polyester resin (UP), alkyd resin, polyurethane (PUR), polyimide (PI), etc. A thermosetting resin or the like can be used.

  As described above, the convex mold 4a is formed on the surface of the film resin of the wave plate 4 with a high aspect ratio of 10 or more by the nanoimprint method, and the concave / convex microstructure is generated at intervals of the convex mold 4a of about several nm to 100 nm. A wave plate with a grating is manufactured.

  According to this wave plate 4 with a diffraction grating, for example, a laser beam having a wavelength range of 300 nm to 450 nm (especially a wavelength of 405 nm) used for HD-DVD or Blue-Ray Disc, Even when polarized by swirling light, it is sufficiently diffracted and exhibits a high efficiency of 90% to 99% diffraction efficiency.

In the above embodiment, the diffraction grating is formed on the wave plate made of film resin such as COP by the nanoimprint method, but the present invention is not limited to this. For example, after forming the uneven shape by nanoimprint, a metal grid such as Al or Si may be laminated on the uneven surface to form a wire grid.

(A) shows the outline of the cross section of the metal mold | die used for the optical nanoimprint method concerning this invention. (B) shows a state in which a release film is formed on the mold shown in (A). (C) shows an example of a form in which a diffraction grating is formed on a wavelength plate made of a film resin by a nanoimprint method using the mold with a release film shown in (B).

Explanation of symbols

1 Mold 1a Convex 4 Wave plate 4a Convex

Claims (12)

  1. A wave plate with a diffraction grating, wherein a diffraction grating is directly formed on the surface of a wave plate made of film resin without using an adhesive.   2. The wave plate with a diffraction grating according to claim 1, wherein an uneven shape is formed on the surface of the film resin by a nanoimprint method, and the diffraction grating is directly provided on the surface of the film resin.   The wave plate with a diffraction grating according to claim 1 or 2, wherein the film resin has a reduced expansion coefficient.   The wave plate with a diffraction grating according to claim 1 or 2, wherein the film resin has a coefficient of expansion lowered by introducing quartz nanoparticles.   The wavelength plate with a diffraction grating according to any one of claims 1 to 4, wherein the film resin is made of a photocurable resin, and a dye having wavelength selection is introduced into the photocurable resin. .   The wave plate with a diffraction grating according to claim 1, wherein a convex shape is formed on the surface of the film resin with a high aspect ratio of 5 or less.   A method for producing a wave plate with a diffraction grating, wherein a diffraction grating is directly formed on the surface of a wave plate made of film resin without using an adhesive.   The method for producing a wave plate with a diffraction grating according to claim 7, wherein a concavo-convex shape is formed on the surface of the film resin by a nanoimprint method, and the diffraction grating is directly formed on the surface of the film resin.   The method for producing a wave plate with a diffraction grating according to claim 7 or 8, wherein a film resin having a reduced expansion coefficient is used.   The method for producing a wave plate with a diffraction grating according to claim 9, wherein the expansion coefficient of the film resin is lowered by introducing quartz nanoparticles.   The wavelength plate with a diffraction grating according to any one of claims 7 to 10, wherein a photocurable resin is used as a film resin, and a wavelength-selective dye is introduced into the photocurable resin. Production method.   The antireflection coating or the antifouling coating is applied to the element at the time of mold release by using a fluorine-based resin as a mold release material for mold release processing. A method for producing a wave plate with a diffraction grating according to claim 1.

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