WO2012005220A1 - Optical member - Google Patents
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- WO2012005220A1 WO2012005220A1 PCT/JP2011/065305 JP2011065305W WO2012005220A1 WO 2012005220 A1 WO2012005220 A1 WO 2012005220A1 JP 2011065305 W JP2011065305 W JP 2011065305W WO 2012005220 A1 WO2012005220 A1 WO 2012005220A1
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
- G02B1/11—Anti-reflection coatings
- G02B1/118—Anti-reflection coatings having sub-optical wavelength surface structures designed to provide an enhanced transmittance, e.g. moth-eye structures
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
- G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
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- the present invention relates to an optical member for terahertz waves.
- the terahertz wave is an electromagnetic wave having a frequency of about 0.1 THz to 10 THz (wavelength of about 30 ⁇ m to 3 mm), and is expected to be used for various devices such as medical devices and space observation devices.
- the apparatus includes an optical system such as a spectroscopic device for measuring and detecting terahertz waves, and the optical system includes an optical member (lens, window, etc.) made of high resistance silicon or the like that absorbs less terahertz waves. Materials, polarizers, filters, etc.) are used.
- the surface of the optical member is composed of a plurality of convex portions (protrusions having a triangular section, a cone, a pyramid, a truncated pyramid, etc.). It has been proposed to form an antireflection structure (such as a moth-eye structure) (see Patent Documents 1 and 2).
- the width of the convex portion (same as the pitch) is 45 ⁇ m or less and the height is 60 ⁇ m or more, whereby the reflectance of the terahertz wave is reduced compared to a flat plate having no antireflection structure on the surface. Yes.
- Patent Document 1 when the material of the optical member is high-resistance silicon and only the reflectivity of the terahertz wave with an incident angle of 0 ° is evaluated, the pitch of the convex portion is determined regardless of the material of the optical member. However, it has not been confirmed that the antireflection structure having a thickness of 45 ⁇ m or less exhibits the effect of reducing the reflectivity of the terahertz wave. For example, when the material of the optical member is a fluororesin, the antireflection structure having a convex pitch of 45 ⁇ m or less has a terahertz wave reflectance of a flat plate having no antireflection structure on the entire surface over an incident angle of 0 to 80 °.
- An object of the present invention is to provide an optical member having an antireflection structure that has an effect of reducing the reflectivity of terahertz waves and has a small wavelength dependency of the reflectivity of terahertz waves, regardless of the material of the optical member. is there.
- the optical member of the present invention is an optical member for terahertz waves, has an antireflection structure composed of a plurality of convex portions on the surface, and the convex portions are formed in parallel with each other at a predetermined pitch.
- the pitch of the convex portions is 50 ⁇ m or more and less than 300 ⁇ m.
- the shape of the cross section orthogonal to the longitudinal direction of the ridge is preferably a triangle.
- the convex portion is preferably made of a fluororesin.
- the fluororesin is preferably a fluoropolymer having a fluorinated aliphatic ring structure in the main chain.
- the optical member of the present invention has an effect of reducing the reflectivity of the terahertz wave regardless of the material of the optical member, and can reduce the wavelength dependency of the reflectivity of the terahertz wave. It is preferable as an optical member (lens, window material, polarizer, filter, etc.) in various devices such as.
- the optical member of the present invention is an optical member used in an optical system that handles terahertz waves, and has an antireflection structure composed of a plurality of convex portions having a predetermined pitch on the surface.
- an antireflection structure including a plurality of convex portions is formed on the surface of the base material, and a support base material may be provided on the back surface side of the base material.
- Examples of the material for the substrate include high-resistance silicon, crystal, and synthetic resin (fluorine resin, cycloolefin resin, etc.). Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
- the refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
- Examples of the shape of the substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape. What is necessary is just to design the thickness of a base material suitably according to the use of an optical member.
- Examples of the material of the convex portion include high resistance silicon, crystal, synthetic resin (fluorine resin, cycloolefin resin, etc.) and the like. Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
- the refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
- the convex part is preferably made of the same material as the base material and is formed integrally with the base material from the viewpoint of suppressing reflection due to the presence of the interface with the base material.
- line extended to the surface of a base material is mentioned.
- the shape of the ridge include a straight line, a curved line, a bent shape, and the like, and a straight line is preferable from the viewpoint of antireflection. From the viewpoint of preventing reflection, it is preferable that a plurality of ridges exist in parallel and have a striped shape.
- the shape of the cross section perpendicular to the longitudinal direction of the ridge include a triangle, a trapezoid, a rectangle, and a semicircle. From the viewpoint of preventing reflection, a triangle or a trapezoid is preferable, and a triangle is particularly preferable. This is because the reflection at the top of the ridge is reduced and the reflectance is low over a wide wavelength range.
- the pitch P of the convex portions is 50 ⁇ m or more and less than 300 ⁇ m. If the pitch P of the convex portions is 50 ⁇ m or more, there is an effect of reducing the reflectivity of the terahertz wave regardless of the material of the optical member, and the wavelength dependency of the reflectivity of the terahertz wave becomes small.
- the pitch P of the convex portion is preferably the wavelength of the terahertz wave handled by the optical system in which the optical member is used, that is, the used wavelength or less, and is preferably less than 300 ⁇ m from the viewpoint of suppressing the generation of diffracted light, and sufficiently generates diffracted light. From the point of restraining to 75 micrometers or less, it is still more preferable.
- the pitch P of the convex portion is the sum of the width of the bottom portion of the convex portion and the width of the bottom portion of the groove formed between the convex portions.
- the aspect ratio (H / P) of the convex portion (height H of the convex portion / pitch P of the convex portion) is not particularly limited, but is preferably 0.3 to 5. Particularly preferred is 0.5-3.
- the width W of the bottom of the convex portion is the same as the pitch P of the convex portion when the convex portions are arranged without a gap.
- the width W of the bottom of the convex portion is preferably 0.5 to 1 times the pitch P of the convex portion, and particularly preferably 1 time. This is because if there is a flat part at the bottom of the convex part, reflected light is generated from that part and the reflection reduction effect is reduced.
- the width W of the bottom of the convex portion is the length of the bottom in the cross section orthogonal to the longitudinal direction.
- Examples of the material for the supporting substrate include those used as materials for conventional optical members for terahertz waves. For example, high resistance silicon, crystal, gallium-germanium alloy, synthetic quartz, resin (polyethylene, polyfluoroethylene, etc.) and the like can be mentioned, and high resistance silicon, crystal and the like are preferably used.
- Examples of the shape of the supporting substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape. What is necessary is just to design the thickness of a support base material suitably according to the use of an optical member.
- Fluoropolymers include fluorine-containing polymers having a fluorine-containing aliphatic ring structure in the main chain, ethylene-tetrafluoroethylene copolymer (ETFE), propylene-tetrafluoroethylene copolymer, vinyl ether-chlorotrifluoroethylene copolymer Examples thereof include vinylidene fluoride-trifluoroethylene copolymer and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
- ETFE ethylene-tetrafluoroethylene copolymer
- propylene-tetrafluoroethylene copolymer propylene-tetrafluoroethylene copolymer
- vinyl ether-chlorotrifluoroethylene copolymer examples thereof include vinylidene fluoride-trifluoroethylene copolymer and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer.
- a fluorine-containing polymer or ETFE having a fluorine-containing aliphatic ring structure in the main chain is preferred, and a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is particularly preferred.
- the fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is an amorphous or amorphous polymer. Having a fluorinated aliphatic ring structure in the main chain means that at least one carbon atom constituting the ring of the fluorinated aliphatic ring in the polymer is a carbon atom constituting the main chain of the polymer.
- the atoms constituting the fluorine-containing aliphatic ring may contain oxygen atoms, nitrogen atoms and the like in addition to carbon atoms.
- the fluorine-containing aliphatic ring is preferably a fluorine-containing aliphatic ring having 1 to 2 oxygen atoms.
- the number of atoms constituting the fluorinated aliphatic ring is preferably 4 to 7.
- the fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is obtained by polymerizing a monomer component containing a fluorine-containing monomer capable of forming a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain. Obtained.
- the fluorine-containing monomer has a carbon-carbon double bond and a fluorine-containing aliphatic ring structure, and at least one carbon atom constituting the carbon-carbon double bond is one of the fluorine-containing aliphatic ring structures. And a cyclic diene monomer having two carbon-carbon double bonds.
- the carbon atom constituting the main chain is derived from the carbon atom of the carbon-carbon double bond, and the diene monomer is subjected to cyclopolymerization.
- the obtained polymer it is derived from 4 carbon atoms of 2 carbon-carbon double bonds.
- the ratio of the number of fluorine atoms bonded to carbon atoms to the total number of hydrogen atoms bonded to carbon atoms and fluorine atoms bonded to carbon atoms is 80% or more, respectively. Preferably, 100% is particularly preferable.
- compound (1) or compound (2) is preferable.
- X 1 represents a fluorine atom or a perfluoroalkoxy group having 1 to 3 carbon atoms
- R 1 and R 2 each represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms
- X 2 and X 2 3 represents a fluorine atom or a perfluoroalkyl group having 1 to 9 carbon atoms.
- the perfluoroalkyl group may be linear or branched.
- compound (1) examples include compounds (1-1) to (1-3).
- compound (2) examples include compounds (2-1) to (2-2).
- the compound (3) is preferable.
- Q represents a perfluoroalkylene group having 1 to 3 carbon atoms (which may have an etheric oxygen atom).
- the etheric oxygen atom may be present at one end of the group or may be present at both ends of the group, and the carbon atom of the group May be present between From the viewpoint of cyclopolymerization, it is preferably present at one end of the group.
- a fluorinated polymer having one or more monomer units of the following formulas (I) to (III) is obtained by cyclopolymerization of the compound (3).
- compound (3) include compounds (3-1) to (3-9).
- CF 2 CFOCF (CF 3 )
- CF CF 2 (3-2)
- CF 2 CFOCF (CF 3 )
- CF 2 CF CF 2 (3-4)
- CF 2 CFOCF 2 CF (CF 3 )
- CF CF 2 (3-5)
- the ratio of the monomer units having a fluorinated alicyclic structure to the total monomer units (100 mol%) is preferably 20 mol% or more, preferably 40 mol%. The above is more preferable, and 100 mol% is particularly preferable.
- the monomer unit having a fluorinated alicyclic structure is a monomer unit formed by polymerization of a cyclic monomer or a monomer unit formed by cyclopolymerization of a diene monomer.
- FIG. 1 is a perspective view showing an example of the optical member of the present invention.
- the optical member 10 is formed on the surface of the base material 12 in parallel with each other at a predetermined pitch P, and the cross-sectional shape orthogonal to the length direction is a plurality of ridges 14 (convex portions) having a triangular shape. It has a structure.
- a groove having a V-shaped cross section is formed between the plurality of ridges 14.
- the ridges 14 and the substrate 12 are integrated and are made of the same material.
- the pitch P of the ridges 14 is 50 ⁇ m or more and less than 300 ⁇ m.
- FIG. 2 is a perspective view showing an example of the optical member of the present invention.
- the optical member 11 has a cross-section orthogonal to the length direction formed on the surface of the resin film 22 (base material) formed on the surface of the plate-like support base material 20 in parallel with each other at a predetermined pitch P. It has an antireflection structure composed of a plurality of ridges 14 (convex portions) having a triangular shape. A groove having a V-shaped cross section is formed between the plurality of ridges 14.
- the ridges 14 and the resin film 22 are integrated and are made of the same resin.
- the support base 20 is made of high resistance silicon or the like.
- the pitch P of the ridges 14 is 50 ⁇ m or more and less than 300 ⁇ m.
- Examples of the method for producing the optical member of the present invention include the following methods ( ⁇ ) to ( ⁇ ).
- ( ⁇ ) A method of forming a plurality of convex portions on the surface of a base material by cutting using a dicing saw, a pulse laser or the like.
- ( ⁇ ) A method of forming a plurality of convex portions on the surface of the substrate by photolithography.
- ( ⁇ ) When the substrate is a resin, a method of forming a plurality of convex portions by a known resin molding method.
- Specific examples of the method ( ⁇ ) include the following methods ( ⁇ 1) to ( ⁇ 4).
- a method for obtaining an optical member having a surface of a substrate After injecting molten resin into a cavity of a mold having a concave part obtained by inverting the convex part of the optical member, the resin is cooled to cool the antireflection structure composed of a plurality of convex parts corresponding to the concave part of the mold.
- a method for obtaining an optical member having a surface of a substrate After injecting molten resin into a cavity of a mold having a concave part obtained by inverting the convex part of the optical member, the resin is cooled to cool the antireflection structure composed of a plurality of convex parts corresponding to the concave part of the mold.
- the optical member of the present invention Since the optical member of the present invention has an effect of reducing the reflectance over a wide range of incident angles of light, the terahertz wave light is incident on the optical member of the present invention obliquely to prevent the reflection of the terahertz wave. can do. Further, since the optical member of the present invention is excellent in the effect of reducing the reflectance of polarized light parallel to the longitudinal direction of the ridges, the polarization of the terahertz wave is incident so that the polarization direction and the longitudinal direction of the ridges are parallel. In addition, reflection of terahertz waves can be prevented.
- the surface has an antireflection structure consisting of a plurality of convex portions having a pitch of 50 ⁇ m or more and less than 300 ⁇ m.
- an antireflection structure consisting of a plurality of convex portions having a pitch of 50 ⁇ m or more and less than 300 ⁇ m.
- the surface of the substrate 12 is formed of a plurality of ridges 14 (convex portions) formed in parallel with each other at a predetermined pitch P and having a triangular cross section perpendicular to the length direction.
- the reflectance of the terahertz wave 150 ⁇ m or 500 ⁇ m
- the incident angle was calculated while changing at an interval of 10 ° between 0 and 80 °.
- the polarization in the direction parallel to the ridges 14 is s-polarized light
- the polarization in the perpendicular direction is p-polarized light
- the respective polarizations are calculated.
- GSolver manufactured by Grafting Solver Development Company
- the pitch P of the convex portions and the aspect ratio (H / P) were the values shown in Table 1.
- the width of the bottom of the convex portion is one time the pitch of the convex portion.
- the reflectivity of the terahertz wave is calculated by optical simulation in the same manner as the optical member 10 for the smooth base material (reference) having no antireflection structure on the surface.
- the reflectance and the reflectance of the optical member 10 were compared and evaluated according to the following criteria. The results are shown in Table 1.
- ⁇ The reflectance of the optical member 10 is lower than the reflectance of the reference over the entire incident angle of 0 to 80 °.
- ⁇ The reflectance of the optical member 10 is lower than the reflectance of the reference at some of the incident angles of 0 to 80 °.
- X The reflectance of the optical member 10 is equal to or higher than the reflectance of the reference over almost the entire incident angle of 0 to 80 °.
- Example 11 to 18 The reflectance of the terahertz wave (150 ⁇ m or 500 ⁇ m) is calculated by optical simulation in the same manner as in Examples 1 to 10 except that the material of the substrate 12 and the ridges 14 is high resistance silicon (refractive index: 3.4). And evaluated. The results are shown in Table 2.
- Example 19 As shown in FIG. 1, an antireflection structure comprising a plurality of ridges 14 having a triangular cross-section formed in parallel to each other and at a predetermined pitch P on the surface of the base material 12.
- the reflectance of the terahertz wave (150 ⁇ m to 500 ⁇ m) was calculated for the optical member 10 having the above by optical simulation.
- the material of the substrate 12 and the ridges 14 was quartz (refractive index: 2.108).
- the pitch P of the ridges was 50 ⁇ m, and the aspect ratio (H / P) was 2.
- the width of the bottom of the convex portion is one time the pitch of the convex portion.
- Example 20 to 26 Similarly, the terahertz wave (from 150 ⁇ m to 150 ⁇ m) is similarly applied to the optical member made of the same material as in Example 19 having an antireflection structure made of a trapezoid whose cross-sectional shape is orthogonal to the length direction.
- the sample having a triangular cross-sectional shape has a lower reflectance than seven samples having a trapezoidal cross-sectional shape trapezoidal.
- the sample having a triangular cross-sectional shape had a lower reflectance than the four samples having a trapezoidal cross-sectional shape.
- the sample having a triangular cross-sectional shape has a higher reflectance than the sample having a trapezoidal cross-sectional shape. From the above, it was found that the reflectance is lower when the cross-sectional shape of the ridge is a triangle than a trapezoid over a wide range of wavelengths.
- the optical member of the present invention is useful as an optical member (lens, window material, polarizer, filter, etc.) used in an optical system that handles terahertz waves. It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-153011 filed on July 5, 2010 are cited herein as the disclosure of the specification of the present invention. Incorporated.
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Abstract
Disclosed is an optical member, comprising a reflection prevention structure that, irrespective of the material of the optical member, has the effect of minimizing terahertz reflectivity, and wherein the wavelength dependency of the terahertz reflectivity is small. A terahertz optical member (10) comprises a reflection prevention structure, which is formed on the surface of a substrate (12), the reflection prevention structure further comprising a plurality of peaks (convex parts) (14), the cross-sections whereof that are orthogonal to the longitudinal direction being triangular, said peaks (convex parts) (14) being formed in parallel and at a prescribed pitch P, wherein the pitch P of the convex parts (14) is greater than or equal to 50μm and less than 300μm.
Description
本発明は、テラヘルツ波用の光学部材に関する。
The present invention relates to an optical member for terahertz waves.
テラヘルツ波は、周波数が約０．１ＴＨｚ～１０ＴＨｚ（波長が約３０μｍ～３ｍｍ）の電磁波であり、医療機器、宇宙観測機器等の各種機器への利用が期待されている。該機器においては、テラヘルツ波の測定、検出のための分光装置等の光学系が備えられており、該光学系には、テラヘルツ波の吸収が少ない高抵抗シリコン等からなる光学部材（レンズ、窓材、偏光子、フィルタ等）が用いられている。
The terahertz wave is an electromagnetic wave having a frequency of about 0.1 THz to 10 THz (wavelength of about 30 μm to 3 mm), and is expected to be used for various devices such as medical devices and space observation devices. The apparatus includes an optical system such as a spectroscopic device for measuring and detecting terahertz waves, and the optical system includes an optical member (lens, window, etc.) made of high resistance silicon or the like that absorbs less terahertz waves. Materials, polarizers, filters, etc.) are used.
該光学部材においては、表面におけるテラヘルツ波の反射を抑えてテラヘルツ波の透過率をできるだけ高くすることが求められている。
そこで、光学部材の表面におけるテラヘルツ波の反射率を低減するために、光学部材の表面に、複数の凸部（断面三角形の凸条、円錐形、角錐形、角錐台形等の突起等）からなる反射防止構造（モスアイ構造等）を形成することが提案されている（特許文献１、２参照）。特許文献１においては、凸部の幅（ピッチと同じ）を４５μｍ以下、高さを６０μｍ以上とすることによって、テラヘルツ波の反射率が、表面に反射防止構造のない平板に比べ低減するとされている。 In the optical member, it is required to suppress the reflection of the terahertz wave on the surface and to increase the transmittance of the terahertz wave as much as possible.
Therefore, in order to reduce the reflectivity of the terahertz wave on the surface of the optical member, the surface of the optical member is composed of a plurality of convex portions (protrusions having a triangular section, a cone, a pyramid, a truncated pyramid, etc.). It has been proposed to form an antireflection structure (such as a moth-eye structure) (see Patent Documents 1 and 2). In Patent Document 1, the width of the convex portion (same as the pitch) is 45 μm or less and the height is 60 μm or more, whereby the reflectance of the terahertz wave is reduced compared to a flat plate having no antireflection structure on the surface. Yes.
そこで、光学部材の表面におけるテラヘルツ波の反射率を低減するために、光学部材の表面に、複数の凸部（断面三角形の凸条、円錐形、角錐形、角錐台形等の突起等）からなる反射防止構造（モスアイ構造等）を形成することが提案されている（特許文献１、２参照）。特許文献１においては、凸部の幅（ピッチと同じ）を４５μｍ以下、高さを６０μｍ以上とすることによって、テラヘルツ波の反射率が、表面に反射防止構造のない平板に比べ低減するとされている。 In the optical member, it is required to suppress the reflection of the terahertz wave on the surface and to increase the transmittance of the terahertz wave as much as possible.
Therefore, in order to reduce the reflectivity of the terahertz wave on the surface of the optical member, the surface of the optical member is composed of a plurality of convex portions (protrusions having a triangular section, a cone, a pyramid, a truncated pyramid, etc.). It has been proposed to form an antireflection structure (such as a moth-eye structure) (see Patent Documents 1 and 2). In Patent Document 1, the width of the convex portion (same as the pitch) is 45 μm or less and the height is 60 μm or more, whereby the reflectance of the terahertz wave is reduced compared to a flat plate having no antireflection structure on the surface. Yes.
しかし、特許文献１においては、光学部材の材料が高抵抗シリコンの場合、かつ入射角０゜のテラヘルツ波の反射率のみを評価しており、光学部材の材料によらずに、凸部のピッチが４５μｍ以下の反射防止構造で、テラヘルツ波の反射率の低減効果が発揮されることが確認されているわけではない。
たとえば、光学部材の材料がフッ素樹脂の場合、凸部のピッチが４５μｍ以下の反射防止構造では、テラヘルツ波の反射率が、入射角０～８０°の全体にわたって、表面に反射防止構造のない平板に比べ大きくなる場合がある、すなわち反射率の低減効果がない場合がある。
また、高抵抗シリコンで、かつ凸部のピッチが４５μｍ超の反射防止構造、すなわち特許文献１ではテラヘルツ波の反射率の低減効果がないとされている場合であっても、テラヘルツ波の反射率の低減効果が、入射角０゜のときには発揮されなくても、それ以外の入射角では発揮される場合がある。 However, in Patent Document 1, when the material of the optical member is high-resistance silicon and only the reflectivity of the terahertz wave with an incident angle of 0 ° is evaluated, the pitch of the convex portion is determined regardless of the material of the optical member. However, it has not been confirmed that the antireflection structure having a thickness of 45 μm or less exhibits the effect of reducing the reflectivity of the terahertz wave.
For example, when the material of the optical member is a fluororesin, the antireflection structure having a convex pitch of 45 μm or less has a terahertz wave reflectance of a flat plate having no antireflection structure on the entire surface over an incident angle of 0 to 80 °. There is a case where it becomes larger than that, that is, there is a case where there is no effect of reducing reflectance.
Further, even if the anti-reflection structure is made of high-resistance silicon and the pitch of the protrusions exceeds 45 μm, that is, in Patent Document 1, it is considered that there is no effect of reducing the reflectivity of the terahertz wave, the reflectivity of the terahertz wave Even if the reduction effect is not exhibited at an incident angle of 0 °, it may be exhibited at other incident angles.
たとえば、光学部材の材料がフッ素樹脂の場合、凸部のピッチが４５μｍ以下の反射防止構造では、テラヘルツ波の反射率が、入射角０～８０°の全体にわたって、表面に反射防止構造のない平板に比べ大きくなる場合がある、すなわち反射率の低減効果がない場合がある。
また、高抵抗シリコンで、かつ凸部のピッチが４５μｍ超の反射防止構造、すなわち特許文献１ではテラヘルツ波の反射率の低減効果がないとされている場合であっても、テラヘルツ波の反射率の低減効果が、入射角０゜のときには発揮されなくても、それ以外の入射角では発揮される場合がある。 However, in Patent Document 1, when the material of the optical member is high-resistance silicon and only the reflectivity of the terahertz wave with an incident angle of 0 ° is evaluated, the pitch of the convex portion is determined regardless of the material of the optical member. However, it has not been confirmed that the antireflection structure having a thickness of 45 μm or less exhibits the effect of reducing the reflectivity of the terahertz wave.
For example, when the material of the optical member is a fluororesin, the antireflection structure having a convex pitch of 45 μm or less has a terahertz wave reflectance of a flat plate having no antireflection structure on the entire surface over an incident angle of 0 to 80 °. There is a case where it becomes larger than that, that is, there is a case where there is no effect of reducing reflectance.
Further, even if the anti-reflection structure is made of high-resistance silicon and the pitch of the protrusions exceeds 45 μm, that is, in Patent Document 1, it is considered that there is no effect of reducing the reflectivity of the terahertz wave, the reflectivity of the terahertz wave Even if the reduction effect is not exhibited at an incident angle of 0 °, it may be exhibited at other incident angles.
本発明の目的は、光学部材の材料によらずに、テラヘルツ波の反射率の低減効果があり、かつテラヘルツ波の反射率の波長依存性が小さい反射防止構造を有する光学部材を提供することである。
An object of the present invention is to provide an optical member having an antireflection structure that has an effect of reducing the reflectivity of terahertz waves and has a small wavelength dependency of the reflectivity of terahertz waves, regardless of the material of the optical member. is there.
本発明の光学部材は、テラヘルツ波用の光学部材であって、複数の凸部からなる反射防止構造を表面に有し、前記凸部は互いに平行にかつ所定のピッチで形成された、長尺の凸条からなり、前記凸部のピッチが、５０μｍ以上であり、３００μｍ未満であることを特徴とする。
The optical member of the present invention is an optical member for terahertz waves, has an antireflection structure composed of a plurality of convex portions on the surface, and the convex portions are formed in parallel with each other at a predetermined pitch. The pitch of the convex portions is 50 μm or more and less than 300 μm.
前記凸条の長手方向に直交する断面の形状は、三角形であることが好ましい。
前記凸部は、フッ素樹脂からなることが好ましい。
前記フッ素樹脂は、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体であることが好ましい。 The shape of the cross section orthogonal to the longitudinal direction of the ridge is preferably a triangle.
The convex portion is preferably made of a fluororesin.
The fluororesin is preferably a fluoropolymer having a fluorinated aliphatic ring structure in the main chain.
前記凸部は、フッ素樹脂からなることが好ましい。
前記フッ素樹脂は、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体であることが好ましい。 The shape of the cross section orthogonal to the longitudinal direction of the ridge is preferably a triangle.
The convex portion is preferably made of a fluororesin.
The fluororesin is preferably a fluoropolymer having a fluorinated aliphatic ring structure in the main chain.
本発明の光学部材は、光学部材の材料によらずに、テラヘルツ波の反射率の低減効果があり、かつテラヘルツ波の反射率の波長依存性を小さくすることができ、医療機器、宇宙観測機器などの各種機器における光学部材（レンズ、窓材、偏光子、フィルタ等）として好ましい。
The optical member of the present invention has an effect of reducing the reflectivity of the terahertz wave regardless of the material of the optical member, and can reduce the wavelength dependency of the reflectivity of the terahertz wave. It is preferable as an optical member (lens, window material, polarizer, filter, etc.) in various devices such as.
＜光学部材＞
本発明の光学部材は、テラヘルツ波を取り扱う光学系に用いられる光学部材であって、所定のピッチの複数の凸部からなる反射防止構造を表面に有するものである。具体的には、基材の表面に複数の凸部からなる反射防止構造が形成されたものであり、基材の裏面側に支持基材を有していてもよい。 <Optical member>
The optical member of the present invention is an optical member used in an optical system that handles terahertz waves, and has an antireflection structure composed of a plurality of convex portions having a predetermined pitch on the surface. Specifically, an antireflection structure including a plurality of convex portions is formed on the surface of the base material, and a support base material may be provided on the back surface side of the base material.
本発明の光学部材は、テラヘルツ波を取り扱う光学系に用いられる光学部材であって、所定のピッチの複数の凸部からなる反射防止構造を表面に有するものである。具体的には、基材の表面に複数の凸部からなる反射防止構造が形成されたものであり、基材の裏面側に支持基材を有していてもよい。 <Optical member>
The optical member of the present invention is an optical member used in an optical system that handles terahertz waves, and has an antireflection structure composed of a plurality of convex portions having a predetermined pitch on the surface. Specifically, an antireflection structure including a plurality of convex portions is formed on the surface of the base material, and a support base material may be provided on the back surface side of the base material.
（基材）
基材の材料としては、高抵抗シリコン、水晶、合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）等が挙げられる。テラヘルツ波の反射率が低くなる点から、屈折率が低い合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）が好ましく、合成樹脂の中でもフッ素樹脂等がより好ましい。
合成樹脂の屈折率は１．６６以下が好ましく、１．６０以下がより好ましく、１．５５以下がさらに好ましく、１．５０以下が特に好ましい。
基材の形状としては、フィルム状、シート状、平板状、曲板状、半球状等が挙げられる。
基材の厚さは、光学部材の用途に応じて適宜設計すればよい。 (Base material)
Examples of the material for the substrate include high-resistance silicon, crystal, and synthetic resin (fluorine resin, cycloolefin resin, etc.). Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
The refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
Examples of the shape of the substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape.
What is necessary is just to design the thickness of a base material suitably according to the use of an optical member.
基材の材料としては、高抵抗シリコン、水晶、合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）等が挙げられる。テラヘルツ波の反射率が低くなる点から、屈折率が低い合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）が好ましく、合成樹脂の中でもフッ素樹脂等がより好ましい。
合成樹脂の屈折率は１．６６以下が好ましく、１．６０以下がより好ましく、１．５５以下がさらに好ましく、１．５０以下が特に好ましい。
基材の形状としては、フィルム状、シート状、平板状、曲板状、半球状等が挙げられる。
基材の厚さは、光学部材の用途に応じて適宜設計すればよい。 (Base material)
Examples of the material for the substrate include high-resistance silicon, crystal, and synthetic resin (fluorine resin, cycloolefin resin, etc.). Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
The refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
Examples of the shape of the substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape.
What is necessary is just to design the thickness of a base material suitably according to the use of an optical member.
（凸部）
凸部の材料としては、高抵抗シリコン、水晶、合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）等が挙げられる。テラヘルツ波の反射率が低くなる点から、屈折率が低い合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）が好ましく、合成樹脂の中でもフッ素樹脂等がより好ましい。
合成樹脂の屈折率は１．６６以下が好ましく、１．６０以下がより好ましく、１．５５以下がさらに好ましく、１．５０以下が特に好ましい。
凸部は、基材との界面の存在による反射を抑える点から、基材と同じ材料からなり、基材と一体に形成されていることが好ましい。 (Convex)
Examples of the material of the convex portion include high resistance silicon, crystal, synthetic resin (fluorine resin, cycloolefin resin, etc.) and the like. Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
The refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
The convex part is preferably made of the same material as the base material and is formed integrally with the base material from the viewpoint of suppressing reflection due to the presence of the interface with the base material.
凸部の材料としては、高抵抗シリコン、水晶、合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）等が挙げられる。テラヘルツ波の反射率が低くなる点から、屈折率が低い合成樹脂（フッ素樹脂、シクロオレフィン樹脂等）が好ましく、合成樹脂の中でもフッ素樹脂等がより好ましい。
合成樹脂の屈折率は１．６６以下が好ましく、１．６０以下がより好ましく、１．５５以下がさらに好ましく、１．５０以下が特に好ましい。
凸部は、基材との界面の存在による反射を抑える点から、基材と同じ材料からなり、基材と一体に形成されていることが好ましい。 (Convex)
Examples of the material of the convex portion include high resistance silicon, crystal, synthetic resin (fluorine resin, cycloolefin resin, etc.) and the like. Synthetic resins (fluorine resin, cycloolefin resin, etc.) having a low refractive index are preferred from the viewpoint of low reflectivity of terahertz waves, and among the synthetic resins, fluororesins are more preferred.
The refractive index of the synthetic resin is preferably 1.66 or less, more preferably 1.60 or less, further preferably 1.55 or less, and particularly preferably 1.50 or less.
The convex part is preferably made of the same material as the base material and is formed integrally with the base material from the viewpoint of suppressing reflection due to the presence of the interface with the base material.
凸部としては、基材の表面に延在する長尺の凸条が挙げられる。
凸条の形状としては、直線、曲線、折れ曲がり形状等が挙げられ、反射防止の点から、直線が好ましい。凸条は、反射防止の点から、複数が平行に存在して縞状をなしていることが好ましい。
凸条の長手方向に直交する断面の形状としては、三角形、台形、長方形、半円形等が挙げられ、反射防止の点から、三角形または台形が好ましく、特に三角形が好ましい。凸条の頂部における反射を低減させ、広い波長範囲で反射率が低いからである。 As a convex part, the elongate protruding item | line extended to the surface of a base material is mentioned.
Examples of the shape of the ridge include a straight line, a curved line, a bent shape, and the like, and a straight line is preferable from the viewpoint of antireflection. From the viewpoint of preventing reflection, it is preferable that a plurality of ridges exist in parallel and have a striped shape.
Examples of the shape of the cross section perpendicular to the longitudinal direction of the ridge include a triangle, a trapezoid, a rectangle, and a semicircle. From the viewpoint of preventing reflection, a triangle or a trapezoid is preferable, and a triangle is particularly preferable. This is because the reflection at the top of the ridge is reduced and the reflectance is low over a wide wavelength range.
凸条の形状としては、直線、曲線、折れ曲がり形状等が挙げられ、反射防止の点から、直線が好ましい。凸条は、反射防止の点から、複数が平行に存在して縞状をなしていることが好ましい。
凸条の長手方向に直交する断面の形状としては、三角形、台形、長方形、半円形等が挙げられ、反射防止の点から、三角形または台形が好ましく、特に三角形が好ましい。凸条の頂部における反射を低減させ、広い波長範囲で反射率が低いからである。 As a convex part, the elongate protruding item | line extended to the surface of a base material is mentioned.
Examples of the shape of the ridge include a straight line, a curved line, a bent shape, and the like, and a straight line is preferable from the viewpoint of antireflection. From the viewpoint of preventing reflection, it is preferable that a plurality of ridges exist in parallel and have a striped shape.
Examples of the shape of the cross section perpendicular to the longitudinal direction of the ridge include a triangle, a trapezoid, a rectangle, and a semicircle. From the viewpoint of preventing reflection, a triangle or a trapezoid is preferable, and a triangle is particularly preferable. This is because the reflection at the top of the ridge is reduced and the reflectance is low over a wide wavelength range.
凸部のピッチＰは、５０μｍ以上であり、３００μｍ未満である。凸部のピッチＰが５０μｍ以上であれば、光学部材の材料によらずに、テラヘルツ波の反射率の低減効果があり、かつテラヘルツ波の反射率の波長依存性が小さくなる。
凸部のピッチＰは、光学部材が用いられる光学系で取り扱うテラヘルツ波の波長、すなわち使用波長以下が好ましく、回折光の発生を抑える点からは、３００μｍ未満がより好ましく、回折光の発生を充分に抑える点からは、７５μｍ以下がさらに好ましい。
凸部のピッチＰとは、凸部の底部の幅と、凸部間に形成される溝の底部の幅との合計である。 The pitch P of the convex portions is 50 μm or more and less than 300 μm. If the pitch P of the convex portions is 50 μm or more, there is an effect of reducing the reflectivity of the terahertz wave regardless of the material of the optical member, and the wavelength dependency of the reflectivity of the terahertz wave becomes small.
The pitch P of the convex portion is preferably the wavelength of the terahertz wave handled by the optical system in which the optical member is used, that is, the used wavelength or less, and is preferably less than 300 μm from the viewpoint of suppressing the generation of diffracted light, and sufficiently generates diffracted light. From the point of restraining to 75 micrometers or less, it is still more preferable.
The pitch P of the convex portion is the sum of the width of the bottom portion of the convex portion and the width of the bottom portion of the groove formed between the convex portions.
凸部のピッチＰは、光学部材が用いられる光学系で取り扱うテラヘルツ波の波長、すなわち使用波長以下が好ましく、回折光の発生を抑える点からは、３００μｍ未満がより好ましく、回折光の発生を充分に抑える点からは、７５μｍ以下がさらに好ましい。
凸部のピッチＰとは、凸部の底部の幅と、凸部間に形成される溝の底部の幅との合計である。 The pitch P of the convex portions is 50 μm or more and less than 300 μm. If the pitch P of the convex portions is 50 μm or more, there is an effect of reducing the reflectivity of the terahertz wave regardless of the material of the optical member, and the wavelength dependency of the reflectivity of the terahertz wave becomes small.
The pitch P of the convex portion is preferably the wavelength of the terahertz wave handled by the optical system in which the optical member is used, that is, the used wavelength or less, and is preferably less than 300 μm from the viewpoint of suppressing the generation of diffracted light, and sufficiently generates diffracted light. From the point of restraining to 75 micrometers or less, it is still more preferable.
The pitch P of the convex portion is the sum of the width of the bottom portion of the convex portion and the width of the bottom portion of the groove formed between the convex portions.
凸部のアスペクト比（Ｈ／Ｐ）（凸部の高さＨ／凸部のピッチＰ）は特に限定はないが、０．３～５であることが好ましい。０．５～３であることが特に好ましい。
The aspect ratio (H / P) of the convex portion (height H of the convex portion / pitch P of the convex portion) is not particularly limited, but is preferably 0.3 to 5. Particularly preferred is 0.5-3.
凸部の底部の幅Ｗは、凸部が隙間なく配列している場合は、凸部のピッチＰと同じになる。凸部の底部の幅Ｗは、凸部のピッチＰに対して、０．５～１倍が好ましく、１倍が特に好ましい。凸部の底部に平坦な部分が存在すると、その部分から反射光が発生し、反射低減効果が小さくなるためである。
凸部の底部の幅Ｗとは、長手方向に直交する断面における底辺の長さである。 The width W of the bottom of the convex portion is the same as the pitch P of the convex portion when the convex portions are arranged without a gap. The width W of the bottom of the convex portion is preferably 0.5 to 1 times the pitch P of the convex portion, and particularly preferably 1 time. This is because if there is a flat part at the bottom of the convex part, reflected light is generated from that part and the reflection reduction effect is reduced.
The width W of the bottom of the convex portion is the length of the bottom in the cross section orthogonal to the longitudinal direction.
凸部の底部の幅Ｗとは、長手方向に直交する断面における底辺の長さである。 The width W of the bottom of the convex portion is the same as the pitch P of the convex portion when the convex portions are arranged without a gap. The width W of the bottom of the convex portion is preferably 0.5 to 1 times the pitch P of the convex portion, and particularly preferably 1 time. This is because if there is a flat part at the bottom of the convex part, reflected light is generated from that part and the reflection reduction effect is reduced.
The width W of the bottom of the convex portion is the length of the bottom in the cross section orthogonal to the longitudinal direction.
（支持基材）
支持基材の材料としては、従来のテラヘルツ波用の光学部材の材料として用いられているものが挙げられる。たとえば、高抵抗シリコン、水晶、ガリウム－ゲルマニウム合金、合成石英、樹脂（ポリエチレン、ポリフルオロエチレン等）等が挙げられ、高抵抗シリコン、水晶等が好ましく用いられる。
支持基材の形状としては、フィルム状、シート状、平板状、曲板状、半球状等が挙げられる。
支持基材の厚さは、光学部材の用途に応じて適宜設計すればよい。 (Supporting substrate)
Examples of the material for the supporting substrate include those used as materials for conventional optical members for terahertz waves. For example, high resistance silicon, crystal, gallium-germanium alloy, synthetic quartz, resin (polyethylene, polyfluoroethylene, etc.) and the like can be mentioned, and high resistance silicon, crystal and the like are preferably used.
Examples of the shape of the supporting substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape.
What is necessary is just to design the thickness of a support base material suitably according to the use of an optical member.
支持基材の材料としては、従来のテラヘルツ波用の光学部材の材料として用いられているものが挙げられる。たとえば、高抵抗シリコン、水晶、ガリウム－ゲルマニウム合金、合成石英、樹脂（ポリエチレン、ポリフルオロエチレン等）等が挙げられ、高抵抗シリコン、水晶等が好ましく用いられる。
支持基材の形状としては、フィルム状、シート状、平板状、曲板状、半球状等が挙げられる。
支持基材の厚さは、光学部材の用途に応じて適宜設計すればよい。 (Supporting substrate)
Examples of the material for the supporting substrate include those used as materials for conventional optical members for terahertz waves. For example, high resistance silicon, crystal, gallium-germanium alloy, synthetic quartz, resin (polyethylene, polyfluoroethylene, etc.) and the like can be mentioned, and high resistance silicon, crystal and the like are preferably used.
Examples of the shape of the supporting substrate include a film shape, a sheet shape, a flat plate shape, a curved plate shape, and a hemispherical shape.
What is necessary is just to design the thickness of a support base material suitably according to the use of an optical member.
（フッ素樹脂）
フッ素樹脂としては、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体、エチレン－テトラフルオロエチレン共重合体（ＥＴＦＥ）、プロピレン－テトラフルオロエチレン共重合体、ビニルエーテル－クロロトリフルオロエチレン共重合体、フッ化ビニリデン－トリフルオロエチレン共重合体、テトラフルオロエチレン－・パーフルオロアルキルビニルエーテル共重合体等が挙げられる。屈折率が低い点から、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体またはＥＴＦＥが好ましく、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体が特に好ましい。 (Fluorine resin)
Fluoropolymers include fluorine-containing polymers having a fluorine-containing aliphatic ring structure in the main chain, ethylene-tetrafluoroethylene copolymer (ETFE), propylene-tetrafluoroethylene copolymer, vinyl ether-chlorotrifluoroethylene copolymer Examples thereof include vinylidene fluoride-trifluoroethylene copolymer and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. From the viewpoint of a low refractive index, a fluorine-containing polymer or ETFE having a fluorine-containing aliphatic ring structure in the main chain is preferred, and a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is particularly preferred.
フッ素樹脂としては、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体、エチレン－テトラフルオロエチレン共重合体（ＥＴＦＥ）、プロピレン－テトラフルオロエチレン共重合体、ビニルエーテル－クロロトリフルオロエチレン共重合体、フッ化ビニリデン－トリフルオロエチレン共重合体、テトラフルオロエチレン－・パーフルオロアルキルビニルエーテル共重合体等が挙げられる。屈折率が低い点から、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体またはＥＴＦＥが好ましく、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体が特に好ましい。 (Fluorine resin)
Fluoropolymers include fluorine-containing polymers having a fluorine-containing aliphatic ring structure in the main chain, ethylene-tetrafluoroethylene copolymer (ETFE), propylene-tetrafluoroethylene copolymer, vinyl ether-chlorotrifluoroethylene copolymer Examples thereof include vinylidene fluoride-trifluoroethylene copolymer and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. From the viewpoint of a low refractive index, a fluorine-containing polymer or ETFE having a fluorine-containing aliphatic ring structure in the main chain is preferred, and a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is particularly preferred.
主鎖に含フッ素脂肪族環構造を有する含フッ素重合体は、無定形または非結晶性の重合体である。
主鎖に含フッ素脂肪族環構造を有するとは、重合体における含フッ素脂肪族環の環を構成する炭素原子の１個以上が重合体の主鎖を構成する炭素原子であることをいう。含フッ素脂肪族環の環を構成する原子は、炭素原子以外に酸素原子、窒素原子等を含んでいてもよい。含フッ素脂肪族環としては、１～２個の酸素原子を有する含フッ素脂肪族環が好ましい。含フッ素脂肪族環を構成する原子の数は、４～７個が好ましい。 The fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is an amorphous or amorphous polymer.
Having a fluorinated aliphatic ring structure in the main chain means that at least one carbon atom constituting the ring of the fluorinated aliphatic ring in the polymer is a carbon atom constituting the main chain of the polymer. The atoms constituting the fluorine-containing aliphatic ring may contain oxygen atoms, nitrogen atoms and the like in addition to carbon atoms. The fluorine-containing aliphatic ring is preferably a fluorine-containing aliphatic ring having 1 to 2 oxygen atoms. The number of atoms constituting the fluorinated aliphatic ring is preferably 4 to 7.
主鎖に含フッ素脂肪族環構造を有するとは、重合体における含フッ素脂肪族環の環を構成する炭素原子の１個以上が重合体の主鎖を構成する炭素原子であることをいう。含フッ素脂肪族環の環を構成する原子は、炭素原子以外に酸素原子、窒素原子等を含んでいてもよい。含フッ素脂肪族環としては、１～２個の酸素原子を有する含フッ素脂肪族環が好ましい。含フッ素脂肪族環を構成する原子の数は、４～７個が好ましい。 The fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is an amorphous or amorphous polymer.
Having a fluorinated aliphatic ring structure in the main chain means that at least one carbon atom constituting the ring of the fluorinated aliphatic ring in the polymer is a carbon atom constituting the main chain of the polymer. The atoms constituting the fluorine-containing aliphatic ring may contain oxygen atoms, nitrogen atoms and the like in addition to carbon atoms. The fluorine-containing aliphatic ring is preferably a fluorine-containing aliphatic ring having 1 to 2 oxygen atoms. The number of atoms constituting the fluorinated aliphatic ring is preferably 4 to 7.
主鎖に含フッ素脂肪族環構造を有する含フッ素重合体は、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体を形成し得る含フッ素単量体を含む単量体成分を重合して得られる。該含フッ素単量体としては、炭素－炭素二重結合および含フッ素脂肪族環構造を有し、かつ炭素－炭素二重結合を構成する少なくとも１つの炭素原子が含フッ素脂肪族環構造の一部を構成する環状単量体、または炭素－炭素二重結合を２つ有する線状のジエン系単量体が挙げられる。
The fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain is obtained by polymerizing a monomer component containing a fluorine-containing monomer capable of forming a fluorine-containing polymer having a fluorine-containing aliphatic ring structure in the main chain. Obtained. The fluorine-containing monomer has a carbon-carbon double bond and a fluorine-containing aliphatic ring structure, and at least one carbon atom constituting the carbon-carbon double bond is one of the fluorine-containing aliphatic ring structures. And a cyclic diene monomer having two carbon-carbon double bonds.
主鎖を構成する炭素原子は、環状単量体を重合させて得た重合体である場合には炭素－炭素二重結合の炭素原子に由来し、ジエン系単量体を環化重合させて得た重合体である場合には２個の炭素－炭素二重結合の４個の炭素原子に由来する。
In the case of a polymer obtained by polymerizing a cyclic monomer, the carbon atom constituting the main chain is derived from the carbon atom of the carbon-carbon double bond, and the diene monomer is subjected to cyclopolymerization. In the case of the obtained polymer, it is derived from 4 carbon atoms of 2 carbon-carbon double bonds.
環状単量体およびジエン系単量体において、炭素原子に結合した水素原子および炭素原子に結合したフッ素原子の合計数に対する炭素原子に結合したフッ素原子の数の割合は、それぞれ、８０％以上が好ましく、１００％が特に好ましい。
In the cyclic monomer and the diene monomer, the ratio of the number of fluorine atoms bonded to carbon atoms to the total number of hydrogen atoms bonded to carbon atoms and fluorine atoms bonded to carbon atoms is 80% or more, respectively. Preferably, 100% is particularly preferable.
環状単量体としては、化合物（１）または化合物（２）が好ましい。
As the cyclic monomer, compound (1) or compound (2) is preferable.
ただし、Ｘ１は、フッ素原子または炭素原子数１～３のペルフルオロアルコキシ基を示し、Ｒ１およびＲ２は、それぞれフッ素原子または炭素原子数１～６のペルフルオロアルキル基を示し、Ｘ２およびＸ３は、それぞれフッ素原子または炭素原子数１～９のペルフルオロアルキル基を示す。
上記のペルフルオロアルキル基は、直鎖状でも、分岐状でも、どちらでもよい。 X 1 represents a fluorine atom or a perfluoroalkoxy group having 1 to 3 carbon atoms, R 1 and R 2 each represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and X 2 and X 2 3 represents a fluorine atom or a perfluoroalkyl group having 1 to 9 carbon atoms.
The perfluoroalkyl group may be linear or branched.
上記のペルフルオロアルキル基は、直鎖状でも、分岐状でも、どちらでもよい。 X 1 represents a fluorine atom or a perfluoroalkoxy group having 1 to 3 carbon atoms, R 1 and R 2 each represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and X 2 and X 2 3 represents a fluorine atom or a perfluoroalkyl group having 1 to 9 carbon atoms.
The perfluoroalkyl group may be linear or branched.
化合物（１）の具体例としては、化合物（１－１）～（１－３）が挙げられる。
Specific examples of compound (1) include compounds (1-1) to (1-3).
化合物（２）の具体例としては、化合物（２－１）～（２－２）が挙げられる。
Specific examples of compound (2) include compounds (2-1) to (2-2).
ジエン系単量体としては、化合物（３）が好ましい。
ＣＦ２＝ＣＦ－Ｑ－ＣＦ＝ＣＦ２ ・・・（３）
ただし、Ｑは、炭素原子数１～３のペルフルオロアルキレン基（エーテル性酸素原子を有していてもよい。）を示す。エーテル性酸素原子を有するペルフルオロアルキレン基である場合、エーテル性酸素原子は該基の一方の末端に存在していてもよく、該基の両末端に存在していてもよく、該基の炭素原子の間に存在していてもよい。環化重合性の点からは、該基の一方の末端に存在しているのが好ましい。 As the diene monomer, the compound (3) is preferable.
CF 2 = CF-Q-CF = CF 2 (3)
Q represents a perfluoroalkylene group having 1 to 3 carbon atoms (which may have an etheric oxygen atom). In the case of a perfluoroalkylene group having an etheric oxygen atom, the etheric oxygen atom may be present at one end of the group or may be present at both ends of the group, and the carbon atom of the group May be present between From the viewpoint of cyclopolymerization, it is preferably present at one end of the group.
ＣＦ２＝ＣＦ－Ｑ－ＣＦ＝ＣＦ２ ・・・（３）
ただし、Ｑは、炭素原子数１～３のペルフルオロアルキレン基（エーテル性酸素原子を有していてもよい。）を示す。エーテル性酸素原子を有するペルフルオロアルキレン基である場合、エーテル性酸素原子は該基の一方の末端に存在していてもよく、該基の両末端に存在していてもよく、該基の炭素原子の間に存在していてもよい。環化重合性の点からは、該基の一方の末端に存在しているのが好ましい。 As the diene monomer, the compound (3) is preferable.
CF 2 = CF-Q-CF = CF 2 (3)
Q represents a perfluoroalkylene group having 1 to 3 carbon atoms (which may have an etheric oxygen atom). In the case of a perfluoroalkylene group having an etheric oxygen atom, the etheric oxygen atom may be present at one end of the group or may be present at both ends of the group, and the carbon atom of the group May be present between From the viewpoint of cyclopolymerization, it is preferably present at one end of the group.
化合物（３）の環化重合により、下式（Ｉ）～（III）のうちの１種以上のモノマー単位を有する含フッ素重合体が得られる。
A fluorinated polymer having one or more monomer units of the following formulas (I) to (III) is obtained by cyclopolymerization of the compound (3).
化合物（３）の具体例としては、化合物（３－１）～（３－９）が挙げられる。
ＣＦ２＝ＣＦＯＣＦ２ＣＦ＝ＣＦ２ ・・・（３－１）
ＣＦ２＝ＣＦＯＣＦ（ＣＦ３）ＣＦ＝ＣＦ２ ・・・（３－２）
ＣＦ２＝ＣＦＯＣＦ２ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－３）
ＣＦ２＝ＣＦＯＣＦ（ＣＦ３）ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－４）
ＣＦ２＝ＣＦＯＣＦ２ＣＦ（ＣＦ３）ＣＦ＝ＣＦ２ ・・・（３－５）
ＣＦ２＝ＣＦＯＣＦ２ＯＣＦ＝ＣＦ２ ・・・（３－６）
ＣＦ２＝ＣＦＯＣ（ＣＦ３）２ＯＣＦ＝ＣＦ２ ・・・（３－７）
ＣＦ２＝ＣＦＣＦ２ＣＦ＝ＣＦ２ ・・・（３－８）
ＣＦ２＝ＣＦＣＦ２ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－９） Specific examples of compound (3) include compounds (3-1) to (3-9).
CF 2 = CFOCF 2 CF = CF 2 (3-1)
CF 2 = CFOCF (CF 3 ) CF = CF 2 (3-2)
CF 2 = CFOCF 2 CF 2 CF = CF 2 (3-3)
CF 2 = CFOCF (CF 3 ) CF 2 CF = CF 2 (3-4)
CF 2 = CFOCF 2 CF (CF 3 ) CF = CF 2 (3-5)
CF 2 = CFOCF 2 OCF = CF 2 (3-6)
CF 2 = CFOC (CF 3 ) 2 OCF = CF 2 (3-7)
CF 2 = CFCF 2 CF = CF 2 (3-8)
CF 2 = CFCF 2 CF 2 CF = CF 2 (3-9)
ＣＦ２＝ＣＦＯＣＦ２ＣＦ＝ＣＦ２ ・・・（３－１）
ＣＦ２＝ＣＦＯＣＦ（ＣＦ３）ＣＦ＝ＣＦ２ ・・・（３－２）
ＣＦ２＝ＣＦＯＣＦ２ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－３）
ＣＦ２＝ＣＦＯＣＦ（ＣＦ３）ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－４）
ＣＦ２＝ＣＦＯＣＦ２ＣＦ（ＣＦ３）ＣＦ＝ＣＦ２ ・・・（３－５）
ＣＦ２＝ＣＦＯＣＦ２ＯＣＦ＝ＣＦ２ ・・・（３－６）
ＣＦ２＝ＣＦＯＣ（ＣＦ３）２ＯＣＦ＝ＣＦ２ ・・・（３－７）
ＣＦ２＝ＣＦＣＦ２ＣＦ＝ＣＦ２ ・・・（３－８）
ＣＦ２＝ＣＦＣＦ２ＣＦ２ＣＦ＝ＣＦ２ ・・・（３－９） Specific examples of compound (3) include compounds (3-1) to (3-9).
CF 2 = CFOCF 2 CF = CF 2 (3-1)
CF 2 = CFOCF (CF 3 ) CF = CF 2 (3-2)
CF 2 = CFOCF 2 CF 2 CF = CF 2 (3-3)
CF 2 = CFOCF (CF 3 ) CF 2 CF = CF 2 (3-4)
CF 2 = CFOCF 2 CF (CF 3 ) CF = CF 2 (3-5)
CF 2 = CFOCF 2 OCF = CF 2 (3-6)
CF 2 = CFOC (CF 3 ) 2 OCF = CF 2 (3-7)
CF 2 = CFCF 2 CF = CF 2 (3-8)
CF 2 = CFCF 2 CF 2 CF = CF 2 (3-9)
主鎖に含フッ素脂肪族環構造を有する含フッ素重合体において、全モノマー単位（１００モル％）に対する含フッ素脂肪族環構造を有するモノマー単位の割合は、２０モル％以上が好ましく、４０モル％以上がより好ましく、１００モル％が特に好ましい。含フッ素脂肪族環構造を有するモノマー単位とは、環状単量体の重合により形成されたモノマー単位、またはジエン系単量体の環化重合により形成されたモノマー単位である。
In the fluorinated polymer having a fluorinated aliphatic ring structure in the main chain, the ratio of the monomer units having a fluorinated alicyclic structure to the total monomer units (100 mol%) is preferably 20 mol% or more, preferably 40 mol%. The above is more preferable, and 100 mol% is particularly preferable. The monomer unit having a fluorinated alicyclic structure is a monomer unit formed by polymerization of a cyclic monomer or a monomer unit formed by cyclopolymerization of a diene monomer.
（第１の実施形態）
図１は、本発明の光学部材の一例を示す斜視図である。
光学部材１０は、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有するものである。複数の凸条１４間には、断面Ｖ字形の溝が形成される。凸条１４と基材１２とは、一体化しており、同じ材料からなる。また、凸条１４のピッチＰは、５０μｍ以上であり、３００μｍ未満である。 (First embodiment)
FIG. 1 is a perspective view showing an example of the optical member of the present invention.
Theoptical member 10 is formed on the surface of the base material 12 in parallel with each other at a predetermined pitch P, and the cross-sectional shape orthogonal to the length direction is a plurality of ridges 14 (convex portions) having a triangular shape. It has a structure. A groove having a V-shaped cross section is formed between the plurality of ridges 14. The ridges 14 and the substrate 12 are integrated and are made of the same material. The pitch P of the ridges 14 is 50 μm or more and less than 300 μm.
図１は、本発明の光学部材の一例を示す斜視図である。
光学部材１０は、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有するものである。複数の凸条１４間には、断面Ｖ字形の溝が形成される。凸条１４と基材１２とは、一体化しており、同じ材料からなる。また、凸条１４のピッチＰは、５０μｍ以上であり、３００μｍ未満である。 (First embodiment)
FIG. 1 is a perspective view showing an example of the optical member of the present invention.
The
（第２の実施形態）
図２は、本発明の光学部材の一例を示す斜視図である。
光学部材１１は、板状の支持基材２０の表面に形成された樹脂膜２２（基材）の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有するものである。複数の凸条１４間には、断面Ｖ字形の溝が形成される。凸条１４と樹脂膜２２とは、一体化しており、同じ樹脂からなる。支持基材２０は、高抵抗シリコン等からなる。また、凸条１４のピッチＰは、５０μｍ以上であり、３００μｍ未満である。 (Second Embodiment)
FIG. 2 is a perspective view showing an example of the optical member of the present invention.
The optical member 11 has a cross-section orthogonal to the length direction formed on the surface of the resin film 22 (base material) formed on the surface of the plate-likesupport base material 20 in parallel with each other at a predetermined pitch P. It has an antireflection structure composed of a plurality of ridges 14 (convex portions) having a triangular shape. A groove having a V-shaped cross section is formed between the plurality of ridges 14. The ridges 14 and the resin film 22 are integrated and are made of the same resin. The support base 20 is made of high resistance silicon or the like. The pitch P of the ridges 14 is 50 μm or more and less than 300 μm.
図２は、本発明の光学部材の一例を示す斜視図である。
光学部材１１は、板状の支持基材２０の表面に形成された樹脂膜２２（基材）の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有するものである。複数の凸条１４間には、断面Ｖ字形の溝が形成される。凸条１４と樹脂膜２２とは、一体化しており、同じ樹脂からなる。支持基材２０は、高抵抗シリコン等からなる。また、凸条１４のピッチＰは、５０μｍ以上であり、３００μｍ未満である。 (Second Embodiment)
FIG. 2 is a perspective view showing an example of the optical member of the present invention.
The optical member 11 has a cross-section orthogonal to the length direction formed on the surface of the resin film 22 (base material) formed on the surface of the plate-like
（光学部材の製造方法）
本発明の光学部材を製造する方法としては、たとえば、下記の方法（α）～（γ）が挙げられる。
（α）基材の表面に、ダイシングソー、パルスレーザ等を用いた切削加工によって複数の凸部を形成する方法。
（β）基材の表面に、フォトリソグラフィによって複数の凸部を形成する方法。
（γ）基材が樹脂の場合は、公知の樹脂の成形法によって複数の凸部を形成する方法。 (Optical member manufacturing method)
Examples of the method for producing the optical member of the present invention include the following methods (α) to (γ).
(Α) A method of forming a plurality of convex portions on the surface of a base material by cutting using a dicing saw, a pulse laser or the like.
(Β) A method of forming a plurality of convex portions on the surface of the substrate by photolithography.
(Γ) When the substrate is a resin, a method of forming a plurality of convex portions by a known resin molding method.
本発明の光学部材を製造する方法としては、たとえば、下記の方法（α）～（γ）が挙げられる。
（α）基材の表面に、ダイシングソー、パルスレーザ等を用いた切削加工によって複数の凸部を形成する方法。
（β）基材の表面に、フォトリソグラフィによって複数の凸部を形成する方法。
（γ）基材が樹脂の場合は、公知の樹脂の成形法によって複数の凸部を形成する方法。 (Optical member manufacturing method)
Examples of the method for producing the optical member of the present invention include the following methods (α) to (γ).
(Α) A method of forming a plurality of convex portions on the surface of a base material by cutting using a dicing saw, a pulse laser or the like.
(Β) A method of forming a plurality of convex portions on the surface of the substrate by photolithography.
(Γ) When the substrate is a resin, a method of forming a plurality of convex portions by a known resin molding method.
方法（γ）としては、具体的には、下記の方法（γ１）～（γ４）が挙げられる。
Specific examples of the method (γ) include the following methods (γ1) to (γ4).
（γ１）光学部材の凸部を反転させた凹部を有するモールドの表面に、樹脂を形成し得る単量体を含む光硬化性組成物を塗布した状態（またはモールドと支持基材との間に光硬化性組成物を挟持した状態）にて、光硬化性組成物に放射線（紫外線、電子線等）を照射し、光硬化性組成物を硬化させ、モールドの凹部に対応する複数の凸部からなる反射防止構造を樹脂基材（または樹脂膜）の表面に有する光学部材を得る方法（光インプリント法）。
(Γ1) A state in which a photocurable composition containing a monomer capable of forming a resin is applied to the surface of a mold having a concave portion obtained by inverting the convex portion of the optical member (or between the mold and the support substrate). In a state in which the photocurable composition is sandwiched), the photocurable composition is irradiated with radiation (ultraviolet rays, electron beams, etc.) to cure the photocurable composition, and a plurality of convex portions corresponding to the concave portions of the mold A method for obtaining an optical member having an antireflection structure comprising:
（γ２）樹脂基材（または支持基材の表面に形成された樹脂膜）に、光学部材の凸部を反転させた凹部を有するモールドを、樹脂基材（または樹脂膜）およびモールドの一方または両方を加熱した状態にて押し付け、モールドの凹部に対応する複数の凸部からなる反射防止構造を樹脂基材（または樹脂膜）の表面に有する光学部材を得る方法（熱インプリト法）。
(Γ2) A mold having a resin substrate (or a resin film formed on the surface of the support substrate) having a concave portion obtained by inverting the convex portion of the optical member, one of the resin base material (or resin film) and the mold or A method of obtaining an optical member having a reflection preventing structure composed of a plurality of convex portions corresponding to the concave portions of the mold on the surface of the resin base material (or resin film) by pressing both of them in a heated state (thermal implementation method).
（γ３）光学部材の凸部を反転させた凹部を有するモールドのキャビティ内に、溶融した樹脂を射出した後、冷却して、モールドの凹部に対応する複数の凸部からなる反射防止構造を樹脂基材の表面に有する光学部材を得る方法（射出成形法）。
(Γ3) After injecting molten resin into a cavity of a mold having a concave part obtained by inverting the convex part of the optical member, the resin is cooled to cool the antireflection structure composed of a plurality of convex parts corresponding to the concave part of the mold. A method (injection molding method) for obtaining an optical member having a surface of a substrate.
（γ４）光学部材の凸部を反転させた凹部を有するモールドの表面に、樹脂を溶媒に溶解した塗布液を塗布した後、溶媒を揮発させて、モールドの凹部に対応する複数の凸部からなる反射防止構造を樹脂基材の表面に有する光学部材を得る方法（キャスト法）。
(Γ4) After applying a coating solution in which a resin is dissolved in a solvent to the surface of a mold having a concave portion obtained by inverting the convex portion of the optical member, the solvent is volatilized, and a plurality of convex portions corresponding to the concave portion of the mold A method for obtaining an optical member having an antireflection structure on the surface of a resin substrate (casting method).
（光学部材の使用方法）
本発明の光学部材は、光の入射角の広範囲に渡って、反射率の低減効果があるため、本発明の光学部材に、テラヘルツ波の光を斜めから入射させて、テラヘルツ波の反射を防止することができる。
また、本発明の光学部材は、凸条の長手方向に平行な偏光の反射率の低減効果に優れるため、テラヘルツ波の偏光を偏光方向と凸条の長手方向が平行となるように入射させて、テラヘルツ波の反射を防止することができる。 (How to use optical members)
Since the optical member of the present invention has an effect of reducing the reflectance over a wide range of incident angles of light, the terahertz wave light is incident on the optical member of the present invention obliquely to prevent the reflection of the terahertz wave. can do.
Further, since the optical member of the present invention is excellent in the effect of reducing the reflectance of polarized light parallel to the longitudinal direction of the ridges, the polarization of the terahertz wave is incident so that the polarization direction and the longitudinal direction of the ridges are parallel. In addition, reflection of terahertz waves can be prevented.
本発明の光学部材は、光の入射角の広範囲に渡って、反射率の低減効果があるため、本発明の光学部材に、テラヘルツ波の光を斜めから入射させて、テラヘルツ波の反射を防止することができる。
また、本発明の光学部材は、凸条の長手方向に平行な偏光の反射率の低減効果に優れるため、テラヘルツ波の偏光を偏光方向と凸条の長手方向が平行となるように入射させて、テラヘルツ波の反射を防止することができる。 (How to use optical members)
Since the optical member of the present invention has an effect of reducing the reflectance over a wide range of incident angles of light, the terahertz wave light is incident on the optical member of the present invention obliquely to prevent the reflection of the terahertz wave. can do.
Further, since the optical member of the present invention is excellent in the effect of reducing the reflectance of polarized light parallel to the longitudinal direction of the ridges, the polarization of the terahertz wave is incident so that the polarization direction and the longitudinal direction of the ridges are parallel. In addition, reflection of terahertz waves can be prevented.
（作用効果）
以上説明した本発明の光学部材にあっては、ピッチが５０μｍ以上であり、３００μｍ未満である複数の凸部からなる反射防止構造を表面に有しているため、光学部材の材料によらずに、テラヘルツ波の反射率の低減効果があり、かつテラヘルツ波の反射率の波長依存性が小さい。
また、凸部が、従来の高抵抗シリコン等に比べ、屈折率が充分に低い合成樹脂からなる場合、反射防止構造と空気との界面における屈折率の差が小さくなり、テラヘルツ波の反射率がさらに低くなる。 (Function and effect)
In the optical member of the present invention described above, the surface has an antireflection structure consisting of a plurality of convex portions having a pitch of 50 μm or more and less than 300 μm. There is an effect of reducing the reflectance of the terahertz wave, and the wavelength dependence of the reflectance of the terahertz wave is small.
In addition, when the convex portion is made of a synthetic resin having a sufficiently low refractive index compared to conventional high-resistance silicon or the like, the difference in refractive index at the interface between the antireflection structure and air is reduced, and the reflectivity of the terahertz wave is reduced. Further lower.
以上説明した本発明の光学部材にあっては、ピッチが５０μｍ以上であり、３００μｍ未満である複数の凸部からなる反射防止構造を表面に有しているため、光学部材の材料によらずに、テラヘルツ波の反射率の低減効果があり、かつテラヘルツ波の反射率の波長依存性が小さい。
また、凸部が、従来の高抵抗シリコン等に比べ、屈折率が充分に低い合成樹脂からなる場合、反射防止構造と空気との界面における屈折率の差が小さくなり、テラヘルツ波の反射率がさらに低くなる。 (Function and effect)
In the optical member of the present invention described above, the surface has an antireflection structure consisting of a plurality of convex portions having a pitch of 50 μm or more and less than 300 μm. There is an effect of reducing the reflectance of the terahertz wave, and the wavelength dependence of the reflectance of the terahertz wave is small.
In addition, when the convex portion is made of a synthetic resin having a sufficiently low refractive index compared to conventional high-resistance silicon or the like, the difference in refractive index at the interface between the antireflection structure and air is reduced, and the reflectivity of the terahertz wave is reduced. Further lower.
以下、実施例により本発明をさらに詳しく説明するが、本発明はこれら実施例に限定されない。
例５～９、１３～１７、および１９～２６は実施例であり、例１～４、１０、１１、１２および１８は比較例である。 EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Examples 5-9, 13-17, and 19-26 are examples, and examples 1-4, 10, 11, 12, and 18 are comparative examples.
例５～９、１３～１７、および１９～２６は実施例であり、例１～４、１０、１１、１２および１８は比較例である。 EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.
Examples 5-9, 13-17, and 19-26 are examples, and examples 1-4, 10, 11, 12, and 18 are comparative examples.
〔例１～１０〕
図１に示すような、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有する光学部材１０について、テラヘルツ波（１５０μｍまたは５００μｍ）の反射率を光学シミュレーションによって計算した。入射角については、０～８０°の間で１０°間隔で変化させながら計算した。入射光については、凸条１４に平行な方向の偏光をｓ偏光とし、垂直な方向の偏光をｐ偏光とし、それぞれの偏光について計算した。 [Examples 1 to 10]
As shown in FIG. 1, the surface of thesubstrate 12 is formed of a plurality of ridges 14 (convex portions) formed in parallel with each other at a predetermined pitch P and having a triangular cross section perpendicular to the length direction. For the optical member 10 having the antireflection structure, the reflectance of the terahertz wave (150 μm or 500 μm) was calculated by optical simulation. The incident angle was calculated while changing at an interval of 10 ° between 0 and 80 °. For the incident light, the polarization in the direction parallel to the ridges 14 is s-polarized light, the polarization in the perpendicular direction is p-polarized light, and the respective polarizations are calculated.
図１に示すような、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が三角形の複数の凸条１４（凸部）からなる反射防止構造を有する光学部材１０について、テラヘルツ波（１５０μｍまたは５００μｍ）の反射率を光学シミュレーションによって計算した。入射角については、０～８０°の間で１０°間隔で変化させながら計算した。入射光については、凸条１４に平行な方向の偏光をｓ偏光とし、垂直な方向の偏光をｐ偏光とし、それぞれの偏光について計算した。 [Examples 1 to 10]
As shown in FIG. 1, the surface of the
光学シミュレーションには、ＧＳｏｌｖｅｒ（Ｇｒａｔｉｎｇ Ｓｏｌｖｅｒ Ｄｅｖｅｌｏｐｍｅｎｔ Ｃｏｍｐａｎｙ社製）を用いた。
基材１２および凸条１４の材料は、ＣＦ２＝ＣＦＯＣＦ２ＣＦ＝ＣＦ２の単独重合体（旭硝子社製、サイトップ（登録商標）、屈折率：１．５）とした。
凸部のピッチＰ、およびアスペクト比（Ｈ／Ｐ）は、表１に示す値とした。凸部の底部の幅は凸部のピッチに対して１倍である。 For the optical simulation, GSolver (manufactured by Grafting Solver Development Company) was used.
The material of thesubstrate 12 and the ridges 14 was a homopolymer of CF 2 = CFOCF 2 CF = CF 2 (Cytop (registered trademark), refractive index: 1.5, manufactured by Asahi Glass Co., Ltd.).
The pitch P of the convex portions and the aspect ratio (H / P) were the values shown in Table 1. The width of the bottom of the convex portion is one time the pitch of the convex portion.
基材１２および凸条１４の材料は、ＣＦ２＝ＣＦＯＣＦ２ＣＦ＝ＣＦ２の単独重合体（旭硝子社製、サイトップ（登録商標）、屈折率：１．５）とした。
凸部のピッチＰ、およびアスペクト比（Ｈ／Ｐ）は、表１に示す値とした。凸部の底部の幅は凸部のピッチに対して１倍である。 For the optical simulation, GSolver (manufactured by Grafting Solver Development Company) was used.
The material of the
The pitch P of the convex portions and the aspect ratio (H / P) were the values shown in Table 1. The width of the bottom of the convex portion is one time the pitch of the convex portion.
テラヘルツ波の反射率の低減効果については、表面に反射防止構造を有さない平滑な基材（リファレンス）について、光学部材１０と同様にしてテラヘルツ波の反射率を光学シミュレーションによって計算し、リファレンスの反射率と光学部材１０の反射率とを比較して、下記の基準で評価した。結果を表１に示す。
○：光学部材１０の反射率が、入射角０～８０°の全体にわたって、リファレンスの反射率よりも低い。
△：光学部材１０の反射率が、入射角０～８０°のうち一部の角度において、リファレンスの反射率よりも低い。
×：光学部材１０の反射率が、入射角０～８０°のほぼ全体にわたって、リファレンスの反射率と同等またはリファレンスの反射率よりも高い。 Regarding the effect of reducing the reflectivity of the terahertz wave, the reflectivity of the terahertz wave is calculated by optical simulation in the same manner as theoptical member 10 for the smooth base material (reference) having no antireflection structure on the surface. The reflectance and the reflectance of the optical member 10 were compared and evaluated according to the following criteria. The results are shown in Table 1.
○: The reflectance of theoptical member 10 is lower than the reflectance of the reference over the entire incident angle of 0 to 80 °.
Δ: The reflectance of theoptical member 10 is lower than the reflectance of the reference at some of the incident angles of 0 to 80 °.
X: The reflectance of theoptical member 10 is equal to or higher than the reflectance of the reference over almost the entire incident angle of 0 to 80 °.
○：光学部材１０の反射率が、入射角０～８０°の全体にわたって、リファレンスの反射率よりも低い。
△：光学部材１０の反射率が、入射角０～８０°のうち一部の角度において、リファレンスの反射率よりも低い。
×：光学部材１０の反射率が、入射角０～８０°のほぼ全体にわたって、リファレンスの反射率と同等またはリファレンスの反射率よりも高い。 Regarding the effect of reducing the reflectivity of the terahertz wave, the reflectivity of the terahertz wave is calculated by optical simulation in the same manner as the
○: The reflectance of the
Δ: The reflectance of the
X: The reflectance of the
また、テラヘルツ波の反射率の計算の際に、回折光が発生していないかについてもあわせて調べ、下記の基準にて評価した。結果を表１に示す。
○：入射角０～８０°の全体にわたって、回折光の発生なし。
△：低入射角において回折光の発生はないが、高入射角において回折光の発生がある。
×：入射角０～８０°の全体にわたって、回折光の発生あり。 In addition, when calculating the reflectance of the terahertz wave, whether or not diffracted light was generated was also examined and evaluated according to the following criteria. The results are shown in Table 1.
○: No generation of diffracted light over the entire incident angle of 0 to 80 °.
Δ: No diffracted light is generated at a low incident angle, but diffracted light is generated at a high incident angle.
X: Diffraction light is generated over the entire incident angle range of 0 to 80 °.
○：入射角０～８０°の全体にわたって、回折光の発生なし。
△：低入射角において回折光の発生はないが、高入射角において回折光の発生がある。
×：入射角０～８０°の全体にわたって、回折光の発生あり。 In addition, when calculating the reflectance of the terahertz wave, whether or not diffracted light was generated was also examined and evaluated according to the following criteria. The results are shown in Table 1.
○: No generation of diffracted light over the entire incident angle of 0 to 80 °.
Δ: No diffracted light is generated at a low incident angle, but diffracted light is generated at a high incident angle.
X: Diffraction light is generated over the entire incident angle range of 0 to 80 °.
〔例１１～１８〕
基材１２および凸条１４の材料を、高抵抗シリコン（屈折率：３．４）とした以外は、例１～１０と同様にしてテラヘルツ波（１５０μｍまたは５００μｍ）の反射率を光学シミュレーションによって計算し、評価を行った。結果を表２に示す。 [Examples 11 to 18]
The reflectance of the terahertz wave (150 μm or 500 μm) is calculated by optical simulation in the same manner as in Examples 1 to 10 except that the material of thesubstrate 12 and the ridges 14 is high resistance silicon (refractive index: 3.4). And evaluated. The results are shown in Table 2.
基材１２および凸条１４の材料を、高抵抗シリコン（屈折率：３．４）とした以外は、例１～１０と同様にしてテラヘルツ波（１５０μｍまたは５００μｍ）の反射率を光学シミュレーションによって計算し、評価を行った。結果を表２に示す。 [Examples 11 to 18]
The reflectance of the terahertz wave (150 μm or 500 μm) is calculated by optical simulation in the same manner as in Examples 1 to 10 except that the material of the
〔例１９〕
図１に示すような、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が、三角形の複数の凸条１４からなる反射防止構造を有する光学部材１０について、テラヘルツ波（１５０μｍ～５００μｍ）の反射率を光学シミュレーションによって計算した。
基材１２および凸条１４の材料を、水晶（屈折率：２．１０８）とした。
凸条のピッチＰは５０μｍ、アスペクト比（Ｈ／Ｐ）は２とした。凸部の底部の幅は凸部のピッチに対して１倍である。 Example 19
As shown in FIG. 1, an antireflection structure comprising a plurality ofridges 14 having a triangular cross-section formed in parallel to each other and at a predetermined pitch P on the surface of the base material 12. The reflectance of the terahertz wave (150 μm to 500 μm) was calculated for the optical member 10 having the above by optical simulation.
The material of thesubstrate 12 and the ridges 14 was quartz (refractive index: 2.108).
The pitch P of the ridges was 50 μm, and the aspect ratio (H / P) was 2. The width of the bottom of the convex portion is one time the pitch of the convex portion.
図１に示すような、基材１２の表面に、互いに平行にかつ所定のピッチＰで形成された、長さ方向に直交する断面の形状が、三角形の複数の凸条１４からなる反射防止構造を有する光学部材１０について、テラヘルツ波（１５０μｍ～５００μｍ）の反射率を光学シミュレーションによって計算した。
基材１２および凸条１４の材料を、水晶（屈折率：２．１０８）とした。
凸条のピッチＰは５０μｍ、アスペクト比（Ｈ／Ｐ）は２とした。凸部の底部の幅は凸部のピッチに対して１倍である。 Example 19
As shown in FIG. 1, an antireflection structure comprising a plurality of
The material of the
The pitch P of the ridges was 50 μm, and the aspect ratio (H / P) was 2. The width of the bottom of the convex portion is one time the pitch of the convex portion.
〔例２０～２６〕
また、上記長さ方向に直交する断面の形状を、三角形に替えて台形とした凸条からなる反射防止構造を有する、例１９と同じ材料の光学部材についても、同様に、テラヘルツ波（１５０μｍ～５００μｍ）の反射率を光学シミュレーションによって計算した。台形の上辺をＴ、台形の下辺をＢとしたとき、Ｔ／Ｂ＝０．１、０．２、０．３、０．４、０．５、０．６、および０．７の７サンプルを対象として使用した。 [Examples 20 to 26]
Similarly, the terahertz wave (from 150 μm to 150 μm) is similarly applied to the optical member made of the same material as in Example 19 having an antireflection structure made of a trapezoid whose cross-sectional shape is orthogonal to the length direction. The reflectance of 500 μm) was calculated by optical simulation. 7 samples with T / B = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, where T is the upper side of the trapezoid and B is the lower side of the trapezoid Was used as a target.
また、上記長さ方向に直交する断面の形状を、三角形に替えて台形とした凸条からなる反射防止構造を有する、例１９と同じ材料の光学部材についても、同様に、テラヘルツ波（１５０μｍ～５００μｍ）の反射率を光学シミュレーションによって計算した。台形の上辺をＴ、台形の下辺をＢとしたとき、Ｔ／Ｂ＝０．１、０．２、０．３、０．４、０．５、０．６、および０．７の７サンプルを対象として使用した。 [Examples 20 to 26]
Similarly, the terahertz wave (from 150 μm to 150 μm) is similarly applied to the optical member made of the same material as in Example 19 having an antireflection structure made of a trapezoid whose cross-sectional shape is orthogonal to the length direction. The reflectance of 500 μm) was calculated by optical simulation. 7 samples with T / B = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7, where T is the upper side of the trapezoid and B is the lower side of the trapezoid Was used as a target.
波長１５０μｍ以上３００μｍ以下において、凸条断面の形状が三角形であるサンプルが、凸条断面の形状が台形であるサンプル７点よりも反射率が低かった。
波長３００μｍ超４４０μｍ以下において、凸条断面の形状が三角形であるサンプルが、凸条断面の形状が台形であるサンプル４点よりも反射率が低かった。
波長４４０μｍ超５００μｍ以下において、凸条断面の形状が三角形であるサンプルが、凸条断面の形状が台形であるサンプルよりも反射率が高かった。
以上より、広範囲の波長において、凸条の断面の形状は、台形よりも三角形であるほうが、反射率が低いことがわかった。 At a wavelength of 150 μm or more and 300 μm or less, the sample having a triangular cross-sectional shape has a lower reflectance than seven samples having a trapezoidal cross-sectional shape trapezoidal.
In the wavelength range of more than 300 μm and not more than 440 μm, the sample having a triangular cross-sectional shape had a lower reflectance than the four samples having a trapezoidal cross-sectional shape.
In the wavelength range from 440 μm to 500 μm, the sample having a triangular cross-sectional shape has a higher reflectance than the sample having a trapezoidal cross-sectional shape.
From the above, it was found that the reflectance is lower when the cross-sectional shape of the ridge is a triangle than a trapezoid over a wide range of wavelengths.
波長３００μｍ超４４０μｍ以下において、凸条断面の形状が三角形であるサンプルが、凸条断面の形状が台形であるサンプル４点よりも反射率が低かった。
波長４４０μｍ超５００μｍ以下において、凸条断面の形状が三角形であるサンプルが、凸条断面の形状が台形であるサンプルよりも反射率が高かった。
以上より、広範囲の波長において、凸条の断面の形状は、台形よりも三角形であるほうが、反射率が低いことがわかった。 At a wavelength of 150 μm or more and 300 μm or less, the sample having a triangular cross-sectional shape has a lower reflectance than seven samples having a trapezoidal cross-sectional shape trapezoidal.
In the wavelength range of more than 300 μm and not more than 440 μm, the sample having a triangular cross-sectional shape had a lower reflectance than the four samples having a trapezoidal cross-sectional shape.
In the wavelength range from 440 μm to 500 μm, the sample having a triangular cross-sectional shape has a higher reflectance than the sample having a trapezoidal cross-sectional shape.
From the above, it was found that the reflectance is lower when the cross-sectional shape of the ridge is a triangle than a trapezoid over a wide range of wavelengths.
本発明の光学部材は、テラヘルツ波を取り扱う光学系に用いられる光学部材（レンズ、窓材、偏光子、フィルタ等）として有用である。
なお、２０１０年７月５日に出願された日本特許出願２０１０－１５３０１１号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The optical member of the present invention is useful as an optical member (lens, window material, polarizer, filter, etc.) used in an optical system that handles terahertz waves.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-153011 filed on July 5, 2010 are cited herein as the disclosure of the specification of the present invention. Incorporated.
なお、２０１０年７月５日に出願された日本特許出願２０１０－１５３０１１号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The optical member of the present invention is useful as an optical member (lens, window material, polarizer, filter, etc.) used in an optical system that handles terahertz waves.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-153011 filed on July 5, 2010 are cited herein as the disclosure of the specification of the present invention. Incorporated.
１０ 光学部材
１１ 光学部材
１２ 基材
１４ 凸条（凸部）
２０ 支持基材
２２ 樹脂膜（基材） DESCRIPTION OFSYMBOLS 10 Optical member 11 Optical member 12 Base material 14 Projection (convex part)
20Support base material 22 Resin film (base material)
１１ 光学部材
１２ 基材
１４ 凸条（凸部）
２０ 支持基材
２２ 樹脂膜（基材） DESCRIPTION OF
20
Claims (8)
- テラヘルツ波用の光学部材であって、
複数の凸部からなる反射防止構造を表面に有し、
前記凸部は互いに平行にかつ所定のピッチで形成された、長尺の凸条からなり、
前記凸部のピッチが、５０μｍ以上であり、３００μｍ未満である、光学部材。 An optical member for terahertz waves,
Having an antireflection structure consisting of a plurality of convex portions on the surface,
The convex portions are formed of long ridges formed in parallel with each other at a predetermined pitch,
The optical member whose pitch of the said convex part is 50 micrometers or more and is less than 300 micrometers. - 前記凸条の長手方向に直交する断面の形状が三角形である、請求項１に記載の光学部材。 The optical member according to claim 1, wherein a shape of a cross section perpendicular to the longitudinal direction of the ridge is a triangle.
- 前記凸部の底部の幅が凸部のピッチに対して１倍である、請求項１または２に記載の光学部材。 The optical member according to claim 1 or 2, wherein the width of the bottom of the convex portion is one time the pitch of the convex portion.
- 前記凸部が、屈折率１．６６以下の合成樹脂からなる、請求項１～３のいずれかに記載の光学部材。 The optical member according to any one of claims 1 to 3, wherein the convex portion is made of a synthetic resin having a refractive index of 1.66 or less.
- 前記凸部が、フッ素樹脂からなる、請求項１～４のいずれかに記載の光学部材。 The optical member according to claim 1, wherein the convex portion is made of a fluororesin.
- 前記フッ素樹脂が、主鎖に含フッ素脂肪族環構造を有する含フッ素重合体である、請求項５に記載の光学部材。 The optical member according to claim 5, wherein the fluororesin is a fluoropolymer having a fluoroaliphatic ring structure in the main chain.
- 請求項１～６のいずれかに記載の光学部材に、テラヘルツ波の光を斜めから入射させて、テラヘルツ波の反射を防止する方法。 A method for preventing reflection of terahertz waves by causing light of terahertz waves to enter the optical member according to any one of claims 1 to 6 from an oblique direction.
- 請求項１～６のいずれかに記載の光学部材に、テラヘルツ波の偏光を偏光方向と凸条の長手方向が平行となるように入射させて、テラヘルツ波の反射を防止する方法。 A method for preventing reflection of terahertz waves by allowing the polarization of the terahertz waves to be incident on the optical member according to any one of claims 1 to 6 so that the polarization direction and the longitudinal direction of the ridges are parallel to each other.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012523862A JPWO2012005220A1 (en) | 2010-07-05 | 2011-07-04 | Optical member |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010-153011 | 2010-07-05 | ||
| JP2010153011 | 2010-07-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2012005220A1 true WO2012005220A1 (en) | 2012-01-12 |
Family
ID=45441199
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/JP2011/065305 WO2012005220A1 (en) | 2010-07-05 | 2011-07-04 | Optical member |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPWO2012005220A1 (en) |
| WO (1) | WO2012005220A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11320569B2 (en) | 2018-09-28 | 2022-05-03 | Hamamatsu Photonics K.K. | Optical element for terahertz waves and manufacturing method of the same |
| WO2022264467A1 (en) * | 2021-06-18 | 2022-12-22 | 日本碍子株式会社 | Member for terahertz device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007334306A (en) * | 2006-05-19 | 2007-12-27 | Asahi Glass Co Ltd | Optical waveguide |
| JP2009217085A (en) * | 2008-03-12 | 2009-09-24 | Tochigi Nikon Corp | Optical component |
| JP2009262513A (en) * | 2008-04-30 | 2009-11-12 | Konica Minolta Opto Inc | Process of manufacturing optical film, optical film and mold |
-
2011
- 2011-07-04 WO PCT/JP2011/065305 patent/WO2012005220A1/en active Application Filing
- 2011-07-04 JP JP2012523862A patent/JPWO2012005220A1/en not_active Withdrawn
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007334306A (en) * | 2006-05-19 | 2007-12-27 | Asahi Glass Co Ltd | Optical waveguide |
| JP2009217085A (en) * | 2008-03-12 | 2009-09-24 | Tochigi Nikon Corp | Optical component |
| JP2009262513A (en) * | 2008-04-30 | 2009-11-12 | Konica Minolta Opto Inc | Process of manufacturing optical film, optical film and mold |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11320569B2 (en) | 2018-09-28 | 2022-05-03 | Hamamatsu Photonics K.K. | Optical element for terahertz waves and manufacturing method of the same |
| WO2022264467A1 (en) * | 2021-06-18 | 2022-12-22 | 日本碍子株式会社 | Member for terahertz device |
| JP7220333B1 (en) * | 2021-06-18 | 2023-02-09 | 日本碍子株式会社 | Materials for terahertz devices |
Also Published As
| Publication number | Publication date |
|---|---|
| JPWO2012005220A1 (en) | 2013-09-02 |
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