JP3549108B2 - Anti-reflective porous optical material - Google Patents

Anti-reflective porous optical material Download PDF

Info

Publication number
JP3549108B2
JP3549108B2 JP2002036645A JP2002036645A JP3549108B2 JP 3549108 B2 JP3549108 B2 JP 3549108B2 JP 2002036645 A JP2002036645 A JP 2002036645A JP 2002036645 A JP2002036645 A JP 2002036645A JP 3549108 B2 JP3549108 B2 JP 3549108B2
Authority
JP
Japan
Prior art keywords
refractive index
optical material
porous optical
resin
bubbles
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
JP2002036645A
Other languages
Japanese (ja)
Other versions
JP2002311210A (en
Inventor
恵 石原
俊夫 吉原
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dai Nippon Printing Co Ltd
Original Assignee
Dai Nippon Printing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dai Nippon Printing Co Ltd filed Critical Dai Nippon Printing Co Ltd
Priority to JP2002036645A priority Critical patent/JP3549108B2/en
Publication of JP2002311210A publication Critical patent/JP2002311210A/en
Application granted granted Critical
Publication of JP3549108B2 publication Critical patent/JP3549108B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Landscapes

  • Surface Treatment Of Optical Elements (AREA)
  • Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)

Description

【0001】
【産業上の利用分野】
本発明は、反射防止用多孔質光学材料に関し、特に、透明材料の屈折率を低下させてなる反射防止用多孔質光学材料に関する。
【0002】
【従来の技術】
屈折率の低い光学材料の適用分野には、反射防止膜、光導波路、レンズ、プリズム等があり、ディスプレイ表面からの反射を抑える防眩処理、光導波路のクラッド等に用いられる。
【0003】
ところで、従来、屈折率の低い材料としては、サイトップ(旭化成(株)製)等のフッ素化合物(屈折率:1.34)やフッ化マグネシウム(屈折率:1.38)等の化合物、及び、それらの超微粒子を樹脂等に分散させて形成したもの等がある。
【0004】
【発明が解決しようとする課題】
しかしながら、フッ素化合物、フッ化マグネシウム等の屈折率は高々1.3程度であり、これより低いものを得ることはできなかった。
【0005】
また、超微粒子分散系材料では、その屈折率は、マトリクス材料の屈折率と超微粒子の屈折率との中間の値しかとることができず、フッ化マグネシウムの超微粒子を用いても、1.38以下の値をとることはできない。
【0006】
ところで、反射防止処理については、屈折率の高い材料と低い材料を交互に積層する多層膜による方法と、屈折率の高いガラスあるいはプラスチック等の表面に屈折率の低い材料の単層を設ける方法等がある。後者の場合、屈折率をガラスあるいはプラスチック表面から徐々に低くし、空気の屈折率(=1)に近づけるほどその効果は大きい。そのためには、従来にない低い屈折率を持つ材料が必要である。
【0007】
本発明はこのような状況に鑑みてなされたものであり、その目的は、従来にない低屈折率を可能にする反射防止用光学材料を提供することである。
【0008】
【課題を解決するための手段】
上記目的を達成すべく研究の結果、マトリクス材料中に上記超微粒子の代わりに、真空、空気あるいは窒素等のガスからなる微小な空孔を分散させることにより、マトリクス材料より低い屈折率の光学材料が得られることを見出して本発明を完成したものである。この場合、この多孔質体の空孔は、連続して繋がっている場合とそれぞれが独立した泡状の場合とがある。
【0009】
このような多孔質光学材料を作製する方法としては、多くの方法が考えられるが、以下にいくつかの例を示す。ただし、これらに限定されるものではない。
【0010】
(1)加熱、光あるいは電子線の照射により分解して窒素等のガスを発生する物質をマトリクスとなる樹脂のワニスに分散あるいは溶解させ、乾燥後、加熱、光あるいは電子線照射により気泡を発生させ、多孔質体を得る。マトリクス樹脂としては、アクリル樹脂、ポリエステル樹脂、ウレタン樹脂、ポリカーボネート樹脂等、及び、それらの混合物、共重合体等があり、発泡物質としては、ジアゾ化合物、過酸化物等、及び、それらの混合物がある。
【0011】
(2)樹脂モノマーに発泡物質を分散あるいは溶解させ、重合後あるいはその前又は同時に、加熱、光照射、電子線照射により発泡させて多孔質体を作る。
【0012】
(3)重合による体積収縮率の大きい樹脂モノマーの重合により空孔を作り、多孔質体を得る。
【0013】
(4)重合する際に体積の膨張率が極端に異なる2種以上のモノマーからの共重合体を合成する際に発生する局部的な体積の収縮から微小な空孔を発生させて多孔質体を得る。
【0014】
(5)樹脂モノマーと相分離状態を示す材料とシリコンオイル、液晶等とを混合して樹脂モノマーを重合させた後、シリコンオイル、液晶等を取り除き多孔質体を作る。
【0015】
(6)空気等のガスを含むマイクロカプセル(マイクロバルーン)を(1)のワニスに分散させ、乾燥して多孔質体を作る。
【0016】
(7)金属アルコキサイドと有機高分子との共加水分解、共重縮合(いわゆるゾル−ゲル法)により、分子レベルの有機−無機複合体を作成し、加熱による有機成分を分解させることによって、分子オーダーでの細孔を有する多孔質体を合成する。
【0017】
このようにして得られる多孔質体は、反射防止膜等の光学薄膜材料として用いることもできるし、バルク状に形成して、レンズ、プリズム等に構成して用いることもできる。これらにおいて、グラジエントな屈折率分布を持たせることもできる。屈折率分布を持たせるには、微小空孔の密度を変化させればよい。
【0018】
すなわち、本発明の反射防止用多孔質光学材料は、樹脂モノマーを重合させた、又は、樹脂のワニスからなる透明材料中に独立した泡状の閉じた微小な気泡を分散させてその透明材料自身の屈折率より低い屈折率にしたことを特徴とするものである。
【0019】
この場合、微小な気泡は真空あるいは気体からなり、また、微小な気泡の大きさは10Åから使用波長程度であることが望ましい。そして、本発明の反射防止用多孔質光学材料には屈折率に分布を持たせることもできる。なお、本発明の多孔質光学材料は、光学薄膜材料として用いることができる。
【0020】
【作用】
本発明においては、樹脂モノマーを重合させた、又は、樹脂のワニスからなる透明材料中に独立した泡状の閉じた微小な気泡を分散させてその透明材料自身の屈折率より低い屈折率にすることができるので、反射防止処理において、処理表面層の屈折率を従来に比べてより空気の屈折率に近づけることができるため、大きな反射防止効果が得られる。
【0021】
【実施例】
以下、本発明の反射防止用多孔質光学材料のいくつかの実施例について説明する。
【0022】
実施例1
モノマーとして東亜合成(株)製のアクリル酸誘導体(M−5600)を用い、この中に重合開始部材であり窒素ガスを発生するα、α′−アゾイソブチロニトリルを3.0重量%溶解し、基板上に塗布して電子線照射により表面をゆるやかに硬化させた後、基板を110℃で加熱することにより、樹脂を硬化させると同時に、樹脂中に微小な気泡を内在させた。次いで、アッベ法による屈折率測定を行ったところ、気泡を内在させない樹脂と比べて0.1%以下の屈折率低下が見られた。
【0023】
比較例1
ガスを発生しない重合開始部材としてテトラメチルチウラムジスルフィドを用いた以外は、実施例1と全く同様にして樹脂を合成した。次いで、実施例1と同様の方法で屈折率を測定したが、屈折率に変化は見られなかった。
【0024】
実施例2
モノマーの表面硬化の際に紫外線を用いた以外は、実施例1と全く同様にして樹脂中に気泡を内在させた。次いで、アッベ法による屈折率測定を行ったところ、気泡を内在させない樹脂と比べて0.1%以下の屈折率低下が見られた。
【0025】
実施例3
樹脂として東洋紡績(株)製のポリエステル(バイロン−200)中に発泡部材として1.0重量%の2、2´−アゾビス(2、4−ジメチルバレロニトリル)を溶解し、基板上に塗布後、紫外線照射により発泡部材を分解し、樹脂中に微小な気泡が内在させた。次いで、実施例1と同様の方法で屈折率測定を行ったところ、気泡を内在させない樹脂と比べて0.1%以下の屈折率の低下が見られた。
【0026】
実施例4
金属アルコキサイドのテトラエトキシシラン50gと有機高分子としてアミド基を繰り返し単位とするポリオキサゾリン5gとをエタノール30mlに溶かし、次いで、この溶液に濃塩酸1.2gを45gの純水で希釈した溶液を添加し、基板上に広げて反応させた。生成したゲルを600℃で焼成し、有機高分子を分解させ、細孔を生じさせた。有機高分子の分解温度以下で焼成した生成物に比べて0.1%以下の屈折率低下が見られた。
【0027】
【発明の効果】
以上の説明から明らかなように、本発明の反射防止用多孔質光学材料によると、樹脂モノマーを重合させた、又は、樹脂のワニスからなる透明材料中に独立した泡状の閉じた微小な気泡を分散させてその透明材料自身の屈折率より低い屈折率にすることができるので、反射防止処理において、処理表面層の屈折率を従来に比べてより空気の屈折率に近づけることができるため、大きな反射防止効果が得られる。それ以外にも、低屈折率材料として各方面で有効に利用し得る。
[0001]
[Industrial applications]
The present invention relates to a porous optical material for anti-reflection, and more particularly to a porous optical material for anti-reflection obtained by lowering the refractive index of a transparent material.
[0002]
[Prior art]
Application fields of optical materials having a low refractive index include antireflection films, optical waveguides, lenses, prisms, and the like, which are used for antiglare treatment for suppressing reflection from the display surface, cladding of optical waveguides, and the like.
[0003]
Conventionally, as a material having a low refractive index, compounds such as a fluorine compound (refractive index: 1.34), magnesium fluoride (refractive index: 1.38) such as CYTOP (manufactured by Asahi Kasei Corporation), and And those formed by dispersing these ultrafine particles in a resin or the like.
[0004]
[Problems to be solved by the invention]
However, the refractive index of a fluorine compound, magnesium fluoride, or the like is at most about 1.3, and a refractive index lower than this could not be obtained.
[0005]
Further, in the ultrafine particle dispersion material, the refractive index can take only an intermediate value between the refractive index of the matrix material and the refractive index of the ultrafine particles. The value cannot be less than 38.
[0006]
By the way, regarding the antireflection treatment, a method using a multilayer film in which a material having a high refractive index and a material having a low refractive index are alternately laminated, a method of providing a single layer of a material having a low refractive index on the surface of glass or plastic having a high refractive index, and the like. There is. In the latter case, the effect increases as the refractive index is gradually lowered from the glass or plastic surface and approaches the refractive index of air (= 1). For that purpose, a material having an unprecedented low refractive index is required.
[0007]
The present invention has been made in view of such a situation, and an object of the present invention is to provide an antireflection optical material that enables an unprecedented low refractive index.
[0008]
[Means for Solving the Problems]
As a result of research to achieve the above object, by dispersing minute holes made of gas such as vacuum, air or nitrogen instead of the ultrafine particles in the matrix material, an optical material having a lower refractive index than the matrix material Have been obtained, and the present invention has been completed. In this case, the pores of the porous body may be connected continuously or may be independent foams.
[0009]
As a method for producing such a porous optical material, many methods can be considered, and some examples will be described below. However, it is not limited to these.
[0010]
(1) A substance that decomposes by heating or irradiation with light or an electron beam to generate a gas such as nitrogen is dispersed or dissolved in a resin varnish serving as a matrix. After drying, bubbles are generated by heating, light or electron beam irradiation. To obtain a porous body. Examples of the matrix resin include an acrylic resin, a polyester resin, a urethane resin, a polycarbonate resin, and the like, and a mixture thereof, a copolymer, and the like.As the foaming material, a diazo compound, a peroxide, and the like, and a mixture thereof are used. is there.
[0011]
(2) A foamed substance is dispersed or dissolved in a resin monomer, and foamed by heating, light irradiation, or electron beam irradiation after, before, or simultaneously with polymerization to form a porous body.
[0012]
(3) Voids are formed by polymerization of a resin monomer having a large volume shrinkage due to polymerization to obtain a porous body.
[0013]
(4) Porous material by generating minute pores from local volume shrinkage generated when synthesizing a copolymer from two or more types of monomers having extremely different volume expansion coefficients during polymerization Get.
[0014]
(5) After mixing the resin monomer and a material showing a phase-separated state with silicone oil, liquid crystal and the like to polymerize the resin monomer, the silicon oil, liquid crystal and the like are removed to form a porous body.
[0015]
(6) Microcapsules (microballoons) containing gas such as air are dispersed in the varnish of (1) and dried to form a porous body.
[0016]
(7) A molecular-level organic-inorganic composite is formed by co-hydrolysis and copolycondensation (so-called sol-gel method) of a metal alkoxide and an organic polymer, and the organic component is decomposed by heating to produce a molecule. A porous body having pores on the order is synthesized.
[0017]
The porous body thus obtained can be used as an optical thin film material such as an anti-reflection film, or can be formed into a bulk and used as a lens, a prism, or the like. In these, a gradient refractive index distribution can be provided. In order to have a refractive index distribution, the density of the minute holes may be changed.
[0018]
That is, the antireflection porous optical material of the present invention is obtained by polymerizing a resin monomer or dispersing closed microbubbles in the form of independent bubbles in a transparent material composed of a resin varnish to form the transparent material itself. The refractive index is set to be lower than the refractive index.
[0019]
In this case, the minute bubbles are made of vacuum or gas, and the size of the minute bubbles is desirably about 10 ° to about the wavelength used. The antireflection porous optical material of the present invention may have a distribution in refractive index. In addition, the porous optical material of the present invention can be used as an optical thin film material.
[0020]
[Action]
In the present invention, a resin monomer is polymerized, or dispersed in a transparent material composed of a resin varnish, and fine bubbles, which are independent bubbles, are dispersed to make the refractive index lower than the refractive index of the transparent material itself. Therefore, in the anti-reflection treatment, the refractive index of the treated surface layer can be made closer to the refractive index of air as compared with the related art, so that a large anti-reflection effect can be obtained.
[0021]
【Example】
Hereinafter, several examples of the antireflection porous optical material of the present invention will be described.
[0022]
Example 1
Acrylic acid derivative (M-5600) manufactured by Toa Gosei Co., Ltd. is used as a monomer, and 3.0% by weight of α, α′-azoisobutyronitrile, which is a polymerization initiator and generates nitrogen gas, is dissolved therein. Then, after coating on the substrate and gently curing the surface by electron beam irradiation, the substrate was heated at 110 ° C. to cure the resin, and at the same time, minute bubbles were contained in the resin. Next, when the refractive index was measured by the Abbe method, a decrease in the refractive index of 0.1% or less was observed as compared with the resin in which bubbles were not contained.
[0023]
Comparative Example 1
A resin was synthesized in exactly the same manner as in Example 1 except that tetramethylthiuram disulfide was used as a polymerization-initiating member that did not generate gas. Next, the refractive index was measured in the same manner as in Example 1, but no change was found in the refractive index.
[0024]
Example 2
Bubbles were made to exist inside the resin in exactly the same manner as in Example 1 except that ultraviolet rays were used for curing the surface of the monomer. Next, when the refractive index was measured by the Abbe method, a decrease in the refractive index of 0.1% or less was observed as compared with the resin in which bubbles were not contained.
[0025]
Example 3
After dissolving 1.0% by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) as a foaming member in a polyester (Vylon-200) manufactured by Toyobo Co., Ltd. as a resin, and applying it on a substrate Then, the foamed member was decomposed by the irradiation of ultraviolet rays, and minute bubbles were contained in the resin. Next, the refractive index was measured in the same manner as in Example 1. As a result, a decrease in the refractive index of 0.1% or less was observed as compared with the resin containing no bubbles.
[0026]
Example 4
Dissolve 50 g of metal alkoxide tetraethoxysilane and 5 g of polyoxazoline having an amide group as an organic polymer in 30 ml of ethanol, and then add a solution obtained by diluting 1.2 g of concentrated hydrochloric acid with 45 g of pure water to this solution. Then, it was spread on a substrate and reacted. The resulting gel was calcined at 600 ° C. to decompose the organic polymer and generate pores. A decrease in the refractive index of 0.1% or less was observed as compared with the product fired at a temperature lower than the decomposition temperature of the organic polymer.
[0027]
【The invention's effect】
As is apparent from the above description, according to the porous optical material for antireflection of the present invention, a resin monomer is polymerized, or a closed microbubble in the form of an independent bubble is formed in a transparent material composed of a resin varnish. Can be dispersed to make the refractive index lower than the refractive index of the transparent material itself, so in the antireflection treatment, the refractive index of the treated surface layer can be made closer to the refractive index of air as compared with the conventional one, A large anti-reflection effect can be obtained. In addition, it can be effectively used as a low refractive index material in various fields.

Claims (5)

樹脂モノマーを重合させた、又は、樹脂のワニスからなる透明材料中に独立した泡状の閉じた微小な気泡を分散させてその透明材料自身の屈折率より低い屈折率にしたことを特徴とする反射防止用多孔質光学材料。 The resin monomer was polymerized, or, characterized in that the lower refractive index than the refractive index of the transparent material itself fine bubbles closed form bubbles independent transparent material made of a resin varnish by dispersing Anti-reflective porous optical material. 前記微小な気泡が真空あるいは気体からなることを特徴とする請求項1記載の反射防止用多孔質光学材料。2. The anti-reflection porous optical material according to claim 1, wherein the minute bubbles are made of a vacuum or a gas. 前記微小な気泡の大きさが10Åから使用波長程度であることを特徴とする請求項1又は2記載の反射防止用多孔質光学材料。The porous optical material for anti-reflection according to claim 1 or 2, wherein the size of the minute bubbles is about 10 to about a use wavelength. 屈折率に分布を持たせたことを特徴とする請求項1からの何れか1項記載の反射防止用多孔質光学材料。The antireflection porous optical material according to any one of claims 1 to 3 , wherein the refractive index has a distribution. 光学薄膜材料として用いたことを特徴とする請求項1からの何れか1項記載の反射防止用多孔質光学材料。The porous optical material for anti-reflection according to any one of claims 1 to 4 , wherein the porous optical material is used as an optical thin film material.
JP2002036645A 2002-02-14 2002-02-14 Anti-reflective porous optical material Expired - Lifetime JP3549108B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002036645A JP3549108B2 (en) 2002-02-14 2002-02-14 Anti-reflective porous optical material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002036645A JP3549108B2 (en) 2002-02-14 2002-02-14 Anti-reflective porous optical material

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
JP16324892A Division JPH063501A (en) 1992-06-23 1992-06-23 Porous optical material

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP2004031037A Division JP3649407B2 (en) 2004-02-06 2004-02-06 Porous optical material for antireflection

Publications (2)

Publication Number Publication Date
JP2002311210A JP2002311210A (en) 2002-10-23
JP3549108B2 true JP3549108B2 (en) 2004-08-04

Family

ID=19192616

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002036645A Expired - Lifetime JP3549108B2 (en) 2002-02-14 2002-02-14 Anti-reflective porous optical material

Country Status (1)

Country Link
JP (1) JP3549108B2 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004092840A1 (en) * 2003-04-17 2004-10-28 Nissan Chemical Industries, Ltd. Porous underlayer film and underlayer film forming composition used for forming the same
JP2007308544A (en) * 2006-05-17 2007-11-29 Hitachi Ltd Nano composite material having low dielectric constant and low refractive index
US7821691B2 (en) * 2006-07-28 2010-10-26 CSEM Centre Suisse d'Electronique et de Microtechnique SA—Recherche et Développement Zero-order diffractive filter

Also Published As

Publication number Publication date
JP2002311210A (en) 2002-10-23

Similar Documents

Publication Publication Date Title
JP5345891B2 (en) Anti-glare film and method for producing the same
JPH063501A (en) Porous optical material
JP6856540B2 (en) Production of microporous PMMA foam by the use of nucleating agents
WO2019003905A1 (en) Reflection-preventing film, polarization plate, and image display device
CN102822701A (en) Anti-glare film, manufacturing method of same, polarizing plate and image dislay device
CN103069307A (en) Optical laminate, polarization plate, and image display device
JP2004051783A (en) Photocurable resin composition capable of forming porous material, and porous cured resin
US5679722A (en) Resin composition for production of a three-dimensional object by curing
JP2010090302A (en) Fine particle of curing type fluorine-based acrylic resin and optical material using the same
JP2003213067A (en) Composite material composition, and molded cured article obtained by crosslinking the same
JP3549108B2 (en) Anti-reflective porous optical material
JP2015045718A (en) Hard coat film, polarizing plate, and transmissive liquid crystal display
JP2006116533A (en) Manufacturing method of surface uneven sheet, surface uneven sheet and anti-glaring sheet
JP2004171023A (en) Porous optical material for antireflection
JP4099955B2 (en) (Polymer / liquid crystal) composite film display device and method for manufacturing the same
CN114895386B (en) Anti-glare film, manufacturing method and mold manufacturing method
JPH036265A (en) Coating composition
KR102187883B1 (en) Coating composition of multi function epoxy and arcyl series and manufacturing method thereof
KR20110034237A (en) Spherical multi-layer large polymer particles with low density and preparation method thereof
JP2007328124A (en) Optically anisotropic material and its manufacturing method
JP2008102516A (en) Method of manufacturing (polymer/liquid crystal) composite film display
Si et al. 3D printed hydrogel network regulation based on macroinitiator-induced rapid photoATRP
JPH0834928A (en) Molding of resin composition capable of manifesting reversible cloud point phenomenon with heat and production thereof
JP2001031891A (en) Coating composition and substrate coated with the same
KR101794710B1 (en) Transparent and heat-insulating material including polymer capsule and method for preparing the same

Legal Events

Date Code Title Description
A02 Decision of refusal

Free format text: JAPANESE INTERMEDIATE CODE: A02

Effective date: 20031210

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20040206

A911 Transfer of reconsideration by examiner before appeal (zenchi)

Free format text: JAPANESE INTERMEDIATE CODE: A911

Effective date: 20040219

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20040414

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20040415

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090430

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20090430

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100430

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110430

Year of fee payment: 7

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110430

Year of fee payment: 7

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120430

Year of fee payment: 8

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130430

Year of fee payment: 9

EXPY Cancellation because of completion of term
FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130430

Year of fee payment: 9