JP4216418B2 - PLASTIC OPTICAL FIBER, MANUFACTURING METHOD THEREOF, AND LIGHTING DEVICE USING THE PLASTIC OPTICAL FIBER - Google Patents

PLASTIC OPTICAL FIBER, MANUFACTURING METHOD THEREOF, AND LIGHTING DEVICE USING THE PLASTIC OPTICAL FIBER Download PDF

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JP4216418B2
JP4216418B2 JP28322699A JP28322699A JP4216418B2 JP 4216418 B2 JP4216418 B2 JP 4216418B2 JP 28322699 A JP28322699 A JP 28322699A JP 28322699 A JP28322699 A JP 28322699A JP 4216418 B2 JP4216418 B2 JP 4216418B2
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Prior art keywords
pof
optical fiber
plastic optical
sheath
protective layer
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JP2001108843A5 (en
JP2001108843A (en
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敏則 隅
修 前原
伸二 掛
淳 奥村
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Mitsubishi Chemical Corp
Mitsubishi Rayon Co Ltd
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Mitsubishi Chemical Corp
Mitsubishi Rayon Co Ltd
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  • Light Guides In General And Applications Therefor (AREA)
  • Optical Fibers, Optical Fiber Cores, And Optical Fiber Bundles (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Description

【0001】
【発明の属する技術分野】
本発明は、導光、発光及び照明の技術分野に属するものであり、特に側面漏光特性に優れた光ファイバ及び該光ファイバを用いて導光及び発光を行う照明装置に関するものである。
【0002】
【従来の技術及び発明が解決しようとする課題】
1次光源から発せられる光を光ファイバの端面から該光ファイバ内に入射させ、該光ファイバ内を導光させ、該光ファイバの側面から適宜漏光させることで、該光ファイバ側面を2次光源として利用して、外部に対する照明(照光)を行うことができる。また、このような側面漏光性光ファイバをイルミネーション(電飾)に利用することができる。
【0003】
このような側面漏光を利用する照明用などのプラスチック光ファイバ(以下、適宜「POF」と略す)としては、通常、ポリメチルメタクリレート(PMMA)からなる芯を該芯より屈折率の低いフッ素系ポリマからなる鞘で被覆した構造の直径1.0mm〜0.5mm程度の芯−鞘構造のものが用いられている。そして、十分な光量を得るために、複数の光ファイバを束ねたものが用いられる。この場合、光ファイバの側面漏光特性の向上と漏光量の均一化のために、光ファイバを束ねる際に、らせん状に撚り合わせることが行われている。また、このようにして光ファイバを螺旋状に束ねたものを、透明な塩化ビニル樹脂などのチューブに収納して照明体を構成し、該照明体の少なくとも一方の端部に光源を配置することで照明装置を構成している。
【0004】
しかしながら、POFを長手方向の全体に亘って均一に螺旋状に束ねることはかなり困難であり、POFの側面からの出射光量には長手方向に亘って斑が生じやすい点が問題である。
【0005】
また、特開平7−72341号公報には、紡糸クエンチ工程で、POF中にPOF直径の0.1〜4倍の短長径の気泡を形成し、該気泡による光散乱に基づき側面漏光性を増大させた照明用POFが記載されている。
【0006】
しかしながら、この特開平7−72341号公報に記載のPOFは、大きな散乱が発生するため、光伝送特性(導光特性)が大きく損なわれ、長い距離でこのPOFを用いた場合、長手方向に関する漏光量が不均一となり、また、このPOFも従来の他のPOFと同様に、表面の摩擦抵抗が大きいため、紡糸以降の工程において、たとえばPOFをチューブ中へ収納する作業時等に、過度のこすれ等によってPOF表面の損傷が生じやすく、この場合、損傷を受けていない部分と損傷部分とで光の漏出量が大きく異なることになり、損傷部分が輝点や輝線として現れてしまう点も問題である。
【0007】
そこで、本発明の目的は、光ファイバの長手方向に関する側面漏光の均一性が良好で、光ファイバ表面が多少の損傷を受けても損傷部が輝点や輝線として目視されにくく、また表面の摩擦抵抗が小さく、照明装置製造のために複数を束ねて透明チューブ中へ収納する作業が容易なプラスチック光ファイバを提供することにある。
【0008】
また、本発明は、このようなプラスチック光ファイバを用いた照明装置を提供することをも目的とするものである。
【0009】
【課題を解決するための手段】
本発明によれば、以上のような目的を達成するものとして、芯−鞘構造のプラスチック光ファイバの鞘部の表面に、該鞘部の層厚の20%〜90%の深さで複数個の陥没部が形成されていることを特徴とするプラスチック光ファイバ、が提供される。
【0010】
本発明の一態様においては、芯−鞘構造の外周部に保護層を有するプラスチック光ファイバの保護層の表面に、該保護層の層厚の20%〜100%の深さで複数個の陥没部が形成されている。また、本発明の一態様においては、海−島構造の外周部に保護層を有するプラスチック光ファイバの保護層の表面に、該保護層の層厚の20%〜100%の深さで複数個の陥没部が形成されている。また、本発明の一態様においては、前記陥没部の円形換算直径が50μm以下である。また、本発明の一態様においては、前記複数の陥没部はプラスチック光ファイバの表面に対して20〜80%の面積割合を持つ。
【0011】
更に、本発明によれば、以上のようなプラスチック光ファイバを製造する方法であって、(a)芯−鞘構造のプラスチック光ファイバ、(b)芯−鞘構造の外周部に保護層を有するプラスチック光ファイバ、または(c)海−島構造の外周部に保護層を有するプラスチック光ファイバの軟化状態の表層部に蒸発性または昇華性の微小粒を噴射することで前記(a),(b)または(c)のプラスチック光ファイバの表面に複数の陥没部を形成し、該陥没部内の前記蒸発性または昇華性の微小粒を蒸発または昇華させ、前記プラスチック光ファイバの表層部を硬化させることを特徴とする、プラスチック光ファイバの製造方法が提供される。
【0012】
本発明の一態様においては、前記蒸発性または昇華性の微小粒は前記プラスチック光ファイバの表層部の加熱に寄与する温度で噴射される。また、本発明の一態様においては、前記蒸発性または昇華性の微小粒は水からなる。また、本発明の一態様においては、前記蒸発性または昇華性の微小粒の噴射が、前記プラスチック光ファイバの紡糸工程に引き続いて、該プラスチック光ファイバの表層部が軟化状態にあるうちに開始される。
【0013】
更に、本発明によれば、以上のようなプラスチック光ファイバを複数本束ねてなる照明体と、該照明体の少なくとも一方の端部に配置された光源とを含むことを特徴とする照明装置、が提供される。
【0014】
本発明の一態様においては、前記照明体は前記複数本のプラスチック光ファイバを被覆する透光性チューブを有する。
【0015】
【発明の実施の形態】
以下、図面を参照しながら、本発明の具体的な実施の形態を説明する。
【0016】
(第1の実施形態)
図1は、本発明による芯−鞘の2層構造のプラスチック光ファイバ(POF)の一実施形態の構成を示す模式的断面図である。芯部10を被覆するように周囲に鞘部11が形成されている。POFの断面形状は、好ましくは円形状であるが、これに限定されるものではなく、例えば楕円形状などの非円形状のものであってもよい。また、POFの外径は、特に限定されないが、例えば0.5〜20mm程度である。POFの外径が大きすぎると可撓性が低下し屈曲困難となるおそれがある。
【0017】
芯部10を構成する材料としては、ポリメチルメタクリレート(PMMA)、ポリカーボネート、ポリスチレン等の有機系材料が例示される。芯部10の材料としては、安価で透明性に優れたPMMAが好ましいが、メチルメタクリレート(MMA)とベンジルメタクリレート(BzMA)との共重合体も好ましい材料である。即ち、この共重合体は、光散乱が非常に小さい材料であり、またPMMAに比べ屈折率を高くすることができ、POFで伝送可能な光の入射角を大きくすることができるため、伝送可能な光量を増大させることができ、これにより側面漏光強度も増大し、本発明のPOFの芯部材料として好適に用いることが可能である。
【0018】
鞘部11を構成する材料としては、ポリフッ化ビニリデン、フッ化ビニリデン/テトラフルオロエチレン共重合体、フロロアルキルメタクリレート/メチルメタクリレート系共重合体等の材料が例示される。鞘部11の厚さ(層厚)は、特に限定されないが、例えば2〜20μmであり、好ましくは4〜10μmである。
【0019】
POFの側面(本実施形態では鞘部11の外面)からの漏光を促進させるために、鞘部11の表面には多数の陥没部12が形成されている。図2に鞘部11の表面の展開図を示す。図2に示されているように、陥没部12は好ましくは略円形状(楕円形状などの完全には円形でない形状をも含む)をなしており、その寸法は円形換算直径(長径と短径との平均値)で50μm以下とすることが好ましく、更に好ましくは30μm以下、特に好ましくは20μm以下である。陥没部12の大きさが大きすぎると、形成可能な陥没部12の数が減少するとともに、側面漏光観測時に陥没部が輝点として視認されるようになってしまい、照明効果が低下するおそれがある。また、陥没部12の大きさが小さすぎると、充分な漏光増大効果の得られる深さの陥没部形成が困難となるおそれがあるため、陥没部12の円形換算直径は5μm以上であることが好ましい。陥没部12の深さは、鞘部11の層厚の20%〜90%であり、好ましくは20%〜70%であり、更に好ましくは30%〜50%程度である。陥没部12の深さが深過ぎて芯部10に到達してしまうと、POFの光伝送特性(導光特性)が大幅に損なわれ、側面漏光強度減衰のPOF長さ依存性が増大する。また陥没部12の深さが浅すぎると、充分な漏光促進効果が得られなくなるおそれがある。
【0020】
POFの側面において、多数の陥没部12ができるだけ均一に分布しているのが好ましく、陥没部12の占める面積割合は、20〜80%であることが好ましく、更に好ましくは40〜60%である。陥没部12のPOF表面に占める面積割合が小さすぎると、十分な漏光促進効果を得ることができなくなるおそれがあり、大きすぎると、POFの繰り返し屈曲特性や破断特性などの機械的特性が劣化するおそれがある。
【0021】
尚、鞘部11での光吸収を低減して、POF側面からの漏光量を増大させるためには、芯部10に被覆される鞘部11の材料として透明性に優れた材料を選定することが特に好ましい。
【0022】
以上のような陥没部12の形成された鞘部11を有する芯−鞘構造のPOFに対して、その端部から光を入射させ導光させると、芯部10内の光の一部は鞘部11へと進行し、該鞘部内で陥没部12に到達し、該陥没部12内へと出射し、POF側面漏光が促進される。
【0023】
(第2の実施形態)
図3は、本発明による芯−鞘−保護層の3層構造のPOFの一実施形態の構成を示す模式的断面図である。本実施形態では、上記第1の実施形態と同様な材料からなる芯部10及び鞘部11を有しているが、第1の実施形態とは異なり鞘部11には陥没部が形成されておらず、鞘部11を被覆するように周囲に保護層20が形成されている。
【0024】
保護層20を構成する材料としては、鞘部11と同様な材料が例示されるが、更にポリメチルメタクリレート、ポリカーボネート等の材料を用いてもよい。保護層20の厚さ(層厚)は、特に限定されないが、例えば2〜15μmであり、好ましくは5〜10μmである。
【0025】
鞘部11及び保護層20での光吸収を低減して、POF側面からの漏光量を増大させるためには、芯部10に被覆される鞘部11及び保護層20の材料として透明性に優れた材料を選定することが特に好ましい。
【0026】
POFの側面(本実施形態では保護層20の外面)からの漏光を生じさせるために、保護層20の表面には多数の陥没部12’が形成されている。陥没部12’は、第1の実施形態の陥没部12と同様に、好ましくは略円形状をなしており、その寸法は円形換算直径で例えば50μm以下とすることが好ましく、更に好ましくは30μm以下、特に好ましくは20μm以下である。また、陥没部12’の円形換算直径は5μm以上であることが好ましい。但し、陥没部12’の深さは、保護層20の層厚の20%〜100%であり、好ましくは20%〜90%であり、更に好ましくは50%〜70%程度である。芯−鞘−保護層構造の場合には、陥没部12’が鞘部11に到達しても、POFの光伝送機能が大幅に損なわれることはないが、保護層付与の一つの目的であるPOFの繰り返し屈曲耐性改善効果の低下を引き起こす場合があり、その点から芯−鞘−保護層構造の場合でも、陥没部12’は鞘部11まで到達させないことが望ましく、深過ぎないことが望ましい。また、陥没部12’の深さが浅過ぎると、十分な漏光促進効果が得られなくなるおそれがある。
【0027】
尚、鞘部11及び保護層20での光吸収を低減して、POF側面からの漏光量を増大させるためには、芯部10に被覆される鞘部11及び保護層20の材料として透明性に優れた材料を選定することが特に好ましい。
【0028】
以上のような陥没部12’の形成された保護層20を有する芯−鞘構造のPOFに対して、その端部から光を入射させ導光させると、芯部10内の光の一部は鞘部11へと進行し、更に保護層20へと進行し、該保護層内で陥没部12’に到達し、該陥没部12’内へと出射し、POF側面漏光が促進される。
【0029】
(第3の実施形態)
図4は、本発明による保護層付きの海−島構造のPOFの一実施形態の構成を示す模式的断面図である。
【0030】
本実施形態では、芯または芯−鞘構造からなる島部30を複数本用い、該複数本の島部30を海部31内に配置した多芯構造とし、海部31を被覆するように周囲に保護層20が形成されている。
【0031】
島部30の芯や鞘としては、上記第1の実施形態で説明した芯部及び鞘部と同様な材料からなるものを用いることができる。また、海部31としては、上記第1の実施形態で説明した鞘部や上記第2の実施形態で説明した保護層と同様な材料からなるものを用いることができる。保護層20としては、上記第2の実施形態で説明したものと同様な材料からなるものを用いることができる。
【0032】
島部30の断面形状は代表的には円形状または六角形状であり、該島部30の直径は特に限定されないが20〜1000μm程度とすることが好ましい。また島部30の数は、特に限定されないが、例えば5〜200個程度とすることが好ましい。海部31における複数の島部30の配列は、図4に示されているようにほぼ俵積み形態とすることが好ましい。
【0033】
POFの側面(本実施形態では保護層20の外面)からの漏光を生じさせるために、第2の実施形態と同様に、保護層20の表面には多数の陥没部12’が形成されている。
【0034】
島部30の材料より曲げ弾性率の低い材料を海部31の材料として用いることにより、POFの曲げ弾性率を低下させて屈曲性を向上させることができる。
【0035】
尚、海部31及び保護層20での光吸収を低減して、POF側面からの漏光量を増大させるためには、島部30を包囲する海部31及び保護層20の材料として透明性に優れた材料を選定することが特に好ましい。
【0036】
以上のような陥没部12’の形成された保護層20を有する海−島構造のPOFに対して、その端部から光を入射させ導光させると、島部30内の光の一部は海部31へと進行し、更に保護層20へと進行し、該保護層内で陥没部12’に到達し、該陥没部12’内へと出射し、POF側面漏光が促進される。
【0037】
以上のような多芯POFは、その構造上、曲げに基づくファイバからの漏光の増大が少なく、小さな曲率半径を持つように曲げて用いられる用途へ適用した場合でも、曲げ部分の局所的な漏光増大が少なく、漏光均一性に優れた照明を行うことが可能となる。
【0038】
(第4の実施形態)
図5は、本発明によるPOFの製造方法の一実施形態を示す模式的断面図である。本図は、特にPOF表面の陥没部を形成する工程を示すものである。
【0039】
本実施形態では、一般的なプラスチック光ファイバ製造の例えば加熱延伸工程や加熱処理工程中、あるいはその直後等のファイバ表層部が軟化している状態で、表面に高速で微小粒体をぶつける(噴射する)ことで、POF表面に陥没部を形成した後、表層部を硬化させる。
【0040】
微小粒体としては、樹脂等の表面の梨地処理を行う際に用いられる石英砂やガラスビーズ等を用いることも可能であるが、そのような固形物はPOF表層に食い込んだり、付着して残留したりする可能性があり、その除去回収が必要となるなど、POF外面の陥没部形成のための微小粒体噴射には必ずしも好ましいとはいえない。
【0041】
そこで、本実施形態では、噴射微小粒体として、水、氷及びドライアイスのような加熱等により蒸発または昇華してPOF表面から容易に除去することが可能な材料からなるものを用いる。そして、これらの蒸発性または昇華性の材料からなる噴射微小粒体を用いた場合には、ファイバ加熱処理工程後のPOF冷却冷媒として作用させることも可能であり、好都合である。特に、POFへ高速衝突させる微小粒体へのエネルギー付与が容易で、同時にPOF表層部を軟化させる熱源としても機能することが可能な水蒸気(水)は、本発明のPOF製造のための蒸発性材料として特に好ましく用いられ、水蒸気温度を100℃〜150℃程度とし、水蒸気が気液混合状態である飽和圧力近傍の条件下でPOFの表面に全周にわたって均一噴射することで、POF表層部軟化と微小水粒衝突による表面の陥没部形成とを同時に実施することが可能である。
【0042】
図5において、表面に陥没部を有しないPOF40を多孔筒42の中心部を通るように上向きに走行させながら、該多孔筒42の多数の孔を介して多孔筒外から多孔筒内へと例えば120℃程度の水蒸気を噴射供給する。多孔筒42は、蒸気加熱炉内に配置され、多孔筒内部は供給される飽和状態の加圧水蒸気が多孔筒の両端から排出される際の流動抵抗や、多孔筒両端に設けられた水蒸気の漏洩を防止するシール機構での圧損によって、大気圧に対して加圧状態に保たれる。
【0043】
多孔筒42内では、POF40の表層部が軟化され、表面に水蒸気微粒噴射による陥没部形成を行う。これにより、蒸気加熱炉から出たPOF40の表面には陥没部が形成されており、ここに噴射された水微粒は蒸発により除去される。その際、POFが冷却される。
【0044】
このような微粒噴射による陥没部形成の過程では、POF表面に外力が印加され、これに基づき陥没部12,12’の形成された鞘部11または保護層20に部分的に複屈折構造が生ずる。従って、陥没部12,12’の表面形状に基づく漏光促進効果に加えて、複屈折構造による光学的散乱に基づく漏光促進効果も追加される。
【0045】
また、疑似的な傷とみなすことができる一様分布の多数の陥没部12,12’が表面に形成され、その部分から多くの漏光を生じさせることができるために、陥没部形成の前後において紡糸、後処理、加工工程などでPOF40の表面に損傷を受けても、この損傷部分からの漏光は陥没部からの漏光と混在してしまうため顕著な輝点として視認されることはなくなる。
【0046】
(第5の実施形態)
図6は、本発明によるPOFを用いた照明装置の一実施形態を示す部分断面斜視図である。
【0047】
上記第1〜3の実施形態のようなPOF40または上記第4の実施形態で得られるようなPOF40を複数本(例えば20〜100本)束ね、透光性を有する(好ましくは透明な)可撓性チューブ44内に収納することで、照明体46を形成し、該照明体46の少なくとも一端面に対向するようにして、一次光源48を配置する。これにより、照明装置が得られる。複数のPOF40は互いに平行に配置してもよいし、あるいは適宜の形態にて撚り合わせてもよい。
【0048】
透光性及び可撓性を有するチューブ44としては、例えば厚さ1mm程度の塩化ビニル樹脂製またはポリエチレン製のチューブを用いることができる。チューブ44の長さは30m程度が十分に可能である。また、光源48としては、公知の光源が使用可能であるが、ハロゲンランプ、メタルハライドランプ、高圧水銀灯などの光量の大きい光源を用いることが好ましい。
【0049】
本実施形態の照明装置の製造に際し、複数本のPOF40を束ねたものをチューブ44内に挿入する際には、POF40の表面が多数の陥没部を有することで梨地状となっているため、POF同士あるいはPOFとチューブ内面とが接触する際の摩擦抵抗は低く、POF同士やPOFとチューブ内面とのこすれ等による損傷を軽減することができ、チューブへのPOF挿入が容易となる。
【0050】
更に、漏光促進のためにはチューブ内でPOFを捩るのがよいのであるが、本実施形態では、陥没部に基づく漏光促進効果が十分に大きいため、POFを捩らなくともよく、このためチューブ内へのPOF装填が更に容易になる。
【0051】
本実施形態の照明装置では、各POF内を伝送される光のうちのかなりの部分をPOF表面の陥没部による漏光促進効果で外部へと取り出すことができ、POFの長手方向に沿った漏光光量分布の均一性は良好であり、特異的な輝点や光量斑などの不具合を低減することができる。
【0052】
【実施例】
以下実施例により本発明を具体的に説明する。尚、実施例において「部」は重量部を意味する。
【0053】
〔実施例1〕
芯部用の材料としてポリメチルメタクリレートを用い、また鞘部用の材料としてフッ化ビニリデン/テトラフルオロエチレン=72/28(部)の共重合体を用いて、次のようにして図1に示されているような芯−鞘構造のPOFを製造した。
【0054】
即ち、先ず、芯部用材料樹脂と鞘部用材料樹脂とを、温度220℃に設定された溶融押出機、計量ギヤ式定量ポンプを経て、通常のPOF紡糸に用いられる2層複合紡糸ノズルに供給し、複合紡糸ノズルから吐出させ、一定速度で引き取り、引き続き140℃の熱風加熱炉を用いて2倍加熱延伸を行い、通常の芯−鞘構造のPOFを得た。POFの外径は約1000μmであり、鞘部の層厚は約6μmであった。
【0055】
次に、以上のようにして得られた通常のPOFを、両端にシール機構が設けられPOF通過部の外周に多孔筒が配置されている蒸気加熱炉に通過させ、該蒸気加熱炉の内圧を絶対圧力0.2Mpaに保持し、多孔筒の孔を介してPOFの外表面に対して120℃の水蒸気を噴射供給して、POFの鞘部の表面に円形換算直径が約10μmで表面からの深さ約3μmの略すり鉢状の陥没部を多数形成し、図1に示されるようなPOFを得た。POFの側面において、陥没部が占める面積割合は約50%であった。
【0056】
このPOF60本を互いに平行に束ね、外形12mm、内径10mm、長さ20mの透明な塩化ビニル樹脂製のチューブ内に収納して、照明体を作製した。POF収納作業は容易であり、チューブ内面とPOFとの摩擦による挿入困難はなかった。
【0057】
照明体の両端(POFの束の両端)に面して光源を配置し、該光源から発せられる光を各POF内に入射させ、各POF内を導光させ、該POFの側面から漏光させ、チューブの側面から漏光させたところ、長手方向に関して光量斑は殆どなく、特異的な輝点も観測されなかった。
【0058】
〔実施例2〕
芯部用の材料としてポリメチルメタクリレートを用い、鞘部用の材料として2,2,2−トリフルオロエチルメタクリレート(3FM)/2−(パーフルオロオクチル)エチルメタクリレート(17FM)/メチルメタクリレート(MMA)/メタクリル酸(MAA)=51/30/18/1(部)の共重合体を用い、保護層用の材料として、フッ化ビニリデン/テトラフルオロエチレン=72/28(部)の共重合体を用いて、次のようにして図2に示されているような芯−鞘−保護層構造のPOFを製造した。
【0059】
即ち、先ず、上記芯部用材料樹脂と鞘部用材料樹脂と保護層用材料樹脂とを通常のPOF紡糸に用いられる3層複合紡糸ノズルに供給した以外は実施例1と同様にして、通常の芯−鞘−保護層構造のPOFを得た。POFの外形は約1000μmであり、鞘部の層厚及び保護層の層厚はいずれも約5μmであった。
【0060】
次に、以上のようにして得られた通常のPOFを実施例1と同様にして処理し、POFの保護層の表面に円形換算直径が約10μmで表面からの深さ約3μmの略すり鉢状の陥没部を多数形成し、図3に示されるようなPOFを得た。POFの側面において、陥没部が占める面積割合は約50%であった。
【0061】
このPOF60本を互いに平行に束ね、外形12mm、内径10mm、長さ20mの透明な塩化ビニル樹脂製のチューブ内に収納して、照明体を作製した。POF収納作業は容易であり、チューブ内面とPOFとの摩擦による挿入困難はなかった。
【0062】
照明体の両端(POFの束の両端)に面して光源を配置し、該光源から発せられる光を各POF内に入射させ、各POF内を導光させ、該POFの側面から漏光させ、チューブの側面から漏光させたところ、長手方向に関して光量斑は殆どなく、特異的な輝点も観測されなかった。
【0063】
〔実施例3〕
芯部(島部)用の材料としてポリメチルメタクリレート(PMMA)を用い、海部用の材料及び保護層用の材料としてフッ化ビニリデン/テトラフルオロエチレン=72/28(部)の共重合体を用いて、次のようにして図3に示されているような海−島構造のPOFを製造した。尚、保護層用材料として海部用材料よりも同温度における溶融粘度の低いものを用いた。
【0064】
即ち、複合紡糸ノズルとして、φ20mmの断面内に、内層(孔径1.0mm)/外層(孔径1.1mmから孔径2.3mmへ末広がりのラッパ状)の2層構造ノズルが37個俵積み形態にほぼ均等に配置された構造を有し、外層ノズル孔の下方に入口径φ20mm、吐出孔径φ4mmの漏斗状の絞り部を有し、該絞り部の入口部の外周側面に保護層材料導入部を設置した構造のものを使用した。そして、芯部用材料樹脂を内層ノズルへ導入し、海部用材料樹脂を外層ノズルへ供給し、保護層用材料樹脂を保護層材料導入部へ導入し、外層ノズルの下方において各外層ノズルから吐出される海部材料樹脂どうしを融着させつつ、複合紡糸ノズルから吐出させ、一定速度で引き取って、140℃の熱風加熱炉を用いて2倍の加熱延伸を行い、島部がPMMAのみからなり最外周部に保護層を有する島部数37個の通常の海−島構造のPOFを製造した。POFの外径は1000μmであり、島部の直径は約150μmであり、保護層の厚さは約5μmであった。
【0065】
次に、以上のようにして得られたPOFを、実施例1と同様にして処理し、POFの保護層の表面に円形換算直径が約10μmで表面からの深さ約3μmの略すり鉢状の陥没部を多数形成し、図4に示されるようなPOFを得た。POFの側面において、陥没部が占める面積割合は約50%であった。
【0066】
このPOF60本を互いに平行に束ね、外形12mm、内径10mm、長さ20mの透明な塩化ビニル樹脂製のチューブ内に収納して、照明体を作製した。POF収納作業は容易であり、チューブ内面とPOFとの摩擦による挿入困難はなかった。
【0067】
照明体の両端(POFの束の両端)に面して光源を配置し、該光源から発せられる光を各POF内に入射させ、各POF内を導光させ、該POFの側面から漏光させ、チューブの側面から漏光させたところ、長手方向に関して光量斑は殆どなく、特異的な輝点も観測されなかった。
【0068】
【発明の効果】
以上のように、本発明の光ファイバは、長手方向に関して全体に亘って光量斑なく側面漏光の均一性が良好であり、光ファイバ表面が多少の損傷を受けても損傷部が輝点や輝線として目視されにくい。また、本発明の光ファイバは、表面の摩擦抵抗が小さいので、複数を束ねて透明チューブ中へ収納する作業が容易であり、これを用いて容易に照明装置を製造することができる。
【図面の簡単な説明】
【図1】本発明による芯−鞘の2層構造のプラスチック光ファイバ(POF)の一実施形態の構成を示す模式的断面図である。
【図2】図1の実施形態のプラスチック光ファイバ(POF)の鞘部の表面の展開図である。
【図3】本発明による芯−鞘−保護層の3層構造のプラスチック光ファイバ(POF)の一実施形態の構成を示す模式的断面図である。
【図4】本発明による保護層付きの海−島構造のプラスチック光ファイバ(POF)の一実施形態の構成を示す模式的断面図である。
【図5】本発明によるプラスチック光ファイバ(POF)の製造方法の一実施形態を示す模式的断面図である。
【図6】本発明によるプラスチック光ファイバ(POF)を用いた照明装置の一実施形態を示す部分断面斜視図である。
【符号の説明】
10:芯部
11:鞘部
12,12’:陥没部
20:保護層
30:島部
31:海部
40:プラスチック光ファイバ(POF)
42:多孔筒
44:透光性可撓性チューブ
46:照明体
48:光源
[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of light guide, light emission, and illumination, and particularly relates to an optical fiber having excellent side leakage characteristics and an illumination device that performs light guide and light emission using the optical fiber.
[0002]
[Prior art and problems to be solved by the invention]
The light emitted from the primary light source is incident on the optical fiber from the end face of the optical fiber, guided in the optical fiber, and appropriately leaked from the side surface of the optical fiber, so that the side surface of the optical fiber is secondary light source. Can be used to illuminate (illuminate) the outside. Moreover, such a side light leakage optical fiber can be used for illumination (electrical decoration).
[0003]
As a plastic optical fiber for illumination using such side light leakage (hereinafter abbreviated as “POF” where appropriate), a core made of polymethyl methacrylate (PMMA) is usually a fluorine polymer having a lower refractive index than the core. A core-sheath structure having a diameter of about 1.0 mm to 0.5 mm and a structure covered with a sheath made of In order to obtain a sufficient amount of light, a bundle of a plurality of optical fibers is used. In this case, in order to improve the side light leakage characteristics of the optical fiber and to make the amount of light leakage uniform, when the optical fibers are bundled, they are twisted together in a spiral shape. In addition, the optical fiber bundled in this manner is housed in a tube such as a transparent vinyl chloride resin to form an illuminating body, and a light source is disposed at at least one end of the illuminating body. The lighting device is composed of the above.
[0004]
However, it is quite difficult to bundle POF uniformly in a spiral shape over the entire length direction, and there is a problem in that the amount of light emitted from the side surface of the POF tends to be uneven in the length direction.
[0005]
Japanese Patent Application Laid-Open No. 7-72341 discloses that bubbles are formed in the POF in the POF quenching step by 0.1-4 times shorter and longer diameters than the POF diameter, and the side light leakage is increased based on light scattering by the bubbles. Illuminated POF is described.
[0006]
However, since the POF described in JP-A-7-72341 generates large scattering, the light transmission characteristic (light guide characteristic) is greatly impaired. When this POF is used at a long distance, light leakage in the longitudinal direction occurs. The amount of this non-uniformity becomes large, and this POF, like other conventional POFs, has a large frictional resistance on the surface, so that excessive rubbing occurs, for example, when the POF is stored in the tube in the process after spinning. The surface of the POF is likely to be damaged due to, etc., and in this case, the amount of light leakage differs greatly between the damaged part and the damaged part, and the damaged part appears as a bright spot or bright line. is there.
[0007]
Accordingly, the object of the present invention is that the uniformity of side leakage in the longitudinal direction of the optical fiber is good, and even if the surface of the optical fiber is slightly damaged, the damaged part is difficult to see as a bright spot or bright line, and the surface friction is An object of the present invention is to provide a plastic optical fiber that has a low resistance and that can be easily bundled and housed in a transparent tube for manufacturing a lighting device.
[0008]
Another object of the present invention is to provide an illumination device using such a plastic optical fiber.
[0009]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above-described object, a plurality of layers are formed on the surface of the sheath portion of the core-sheath plastic optical fiber at a depth of 20% to 90% of the layer thickness of the sheath portion. There is provided a plastic optical fiber characterized in that a depression is formed.
[0010]
In one aspect of the invention, Has a protective layer on the outer periphery of the core-sheath structure A plurality of depressions are formed on the surface of the protective layer of the plastic optical fiber at a depth of 20% to 100% of the thickness of the protective layer. In one embodiment of the present invention, a plurality of protective layers having a depth of 20% to 100% of the thickness of the protective layer are formed on the surface of the protective layer of the plastic optical fiber having the protective layer on the outer peripheral portion of the sea-island structure. A depression is formed. Moreover, in 1 aspect of this invention, the circular equivalent diameter of the said depression part is 50 micrometers or less. In one embodiment of the present invention, the plurality of depressions have an area ratio of 20 to 80% with respect to the surface of the plastic optical fiber.
[0011]
Furthermore, according to the present invention, there is provided a method for producing the plastic optical fiber as described above, wherein (a) a plastic optical fiber having a core-sheath structure, (b) Has a protective layer on the outer periphery of the core-sheath structure Evaporable or sublimable fine particles on the surface layer of a plastic optical fiber or (c) a plastic optical fiber having a protective layer on the outer periphery of a sea-island structure in a soft state body Are sprayed to form a plurality of depressions on the surface of the plastic optical fiber of (a), (b) or (c), and the evaporable or sublimable fine particles in the depressions body A method for producing a plastic optical fiber is provided, wherein the surface layer portion of the plastic optical fiber is cured by evaporating or sublimating.
[0012]
In one aspect of the present invention, the evaporable or sublimable fine particles body Is injected at a temperature that contributes to heating of the surface layer of the plastic optical fiber. In one embodiment of the present invention, the evaporable or sublimable fine particles body Consists of water. In one embodiment of the present invention, the evaporable or sublimable fine particles body Is started while the surface layer portion of the plastic optical fiber is in a softened state following the spinning process of the plastic optical fiber.
[0013]
Furthermore, according to the present invention, an illuminating device comprising: an illuminating body formed by bundling a plurality of plastic optical fibers as described above; and a light source disposed at at least one end of the illuminating body, Is provided.
[0014]
In one aspect of the present invention, the illuminator includes a light-transmitting tube that covers the plurality of plastic optical fibers.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0016]
(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a configuration of an embodiment of a plastic optical fiber (POF) having a core-sheath two-layer structure according to the present invention. A sheath portion 11 is formed around the core portion 10 so as to cover the core portion 10. The cross-sectional shape of the POF is preferably a circular shape, but is not limited thereto, and may be a noncircular shape such as an elliptical shape. The outer diameter of the POF is not particularly limited, but is about 0.5 to 20 mm, for example. If the outer diameter of the POF is too large, the flexibility may be reduced, making it difficult to bend.
[0017]
Examples of the material constituting the core 10 include organic materials such as polymethyl methacrylate (PMMA), polycarbonate, and polystyrene. The material for the core 10 is preferably PMMA, which is inexpensive and excellent in transparency, but a copolymer of methyl methacrylate (MMA) and benzyl methacrylate (BzMA) is also a preferred material. In other words, this copolymer is a material that has very little light scattering, can have a higher refractive index than PMMA, and can increase the incident angle of light that can be transmitted by POF. Thus, the amount of side light leakage can be increased and can be suitably used as the core material of the POF of the present invention.
[0018]
Examples of the material constituting the sheath portion 11 include materials such as polyvinylidene fluoride, vinylidene fluoride / tetrafluoroethylene copolymer, and fluoroalkyl methacrylate / methyl methacrylate copolymer. Although the thickness (layer thickness) of the sheath part 11 is not specifically limited, For example, it is 2-20 micrometers, Preferably it is 4-10 micrometers.
[0019]
In order to promote light leakage from the side surface of the POF (the outer surface of the sheath portion 11 in this embodiment), a large number of depressions 12 are formed on the surface of the sheath portion 11. FIG. 2 shows a development view of the surface of the sheath 11. As shown in FIG. 2, the depressed portion 12 preferably has a substantially circular shape (including a shape that is not completely circular, such as an elliptical shape), and the dimensions thereof are circular equivalent diameters (major axis and minor axis). The average value is preferably 50 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. If the size of the depressed portion 12 is too large, the number of the depressed portions 12 that can be formed is reduced, and the depressed portion is visually recognized as a bright spot at the time of side light leakage observation, which may reduce the illumination effect. is there. In addition, if the size of the depressed portion 12 is too small, it may be difficult to form a depressed portion having a depth that can provide a sufficient light leakage enhancement effect. Therefore, the circular equivalent diameter of the depressed portion 12 may be 5 μm or more. preferable. The depth of the depressed portion 12 is 20% to 90% of the layer thickness of the sheath portion 11, preferably 20% to 70%, and more preferably about 30% to 50%. If the depth of the depressed portion 12 is too deep and reaches the core portion 10, the optical transmission characteristic (light guide characteristic) of the POF is greatly impaired, and the dependency of the side light leakage intensity attenuation on the POF length increases. If the depth of the depressed portion 12 is too shallow, a sufficient light leakage promoting effect may not be obtained.
[0020]
On the side of the POF, it is preferable that a large number of depressions 12 are distributed as uniformly as possible, and the area ratio occupied by the depressions 12 is preferably 20 to 80%, and more preferably 40 to 60%. . If the area ratio of the depressed portion 12 on the POF surface is too small, there is a possibility that a sufficient light leakage promoting effect cannot be obtained. If it is too large, mechanical properties such as repeated bending characteristics and fracture characteristics of the POF are deteriorated. There is a fear.
[0021]
In addition, in order to reduce the light absorption in the sheath part 11 and increase the amount of light leakage from the POF side surface, a material having excellent transparency is selected as the material of the sheath part 11 covered with the core part 10. Is particularly preferred.
[0022]
When light is incident and guided from the end portion of the core-sheath POF having the sheath portion 11 in which the depressed portion 12 is formed as described above, a part of the light in the core portion 10 is sheathed. It progresses to the part 11, reaches | attains the depression part 12 in this sheath part, and radiate | emits in this depression part 12, and POF side surface light leakage is accelerated | stimulated.
[0023]
(Second Embodiment)
FIG. 3 is a schematic cross-sectional view showing a configuration of an embodiment of a POF having a three-layer structure of a core-sheath-protective layer according to the present invention. In this embodiment, although it has the core part 10 and the sheath part 11 which consist of the material similar to the said 1st Embodiment, unlike the 1st Embodiment, the depression part is formed in the sheath part 11. In addition, a protective layer 20 is formed around the sheath portion 11 so as to cover the sheath portion 11.
[0024]
Examples of the material constituting the protective layer 20 include the same material as that of the sheath portion 11, but materials such as polymethyl methacrylate and polycarbonate may be used. Although the thickness (layer thickness) of the protective layer 20 is not specifically limited, For example, it is 2-15 micrometers, Preferably it is 5-10 micrometers.
[0025]
In order to reduce the light absorption in the sheath part 11 and the protective layer 20 and increase the amount of light leakage from the POF side surface, the material of the sheath part 11 and the protective layer 20 covered by the core part 10 is excellent in transparency. It is particularly preferable to select the material.
[0026]
In order to cause light leakage from the side surface of the POF (in this embodiment, the outer surface of the protective layer 20), a large number of depressions 12 ′ are formed on the surface of the protective layer 20. The recessed portion 12 ′ is preferably substantially circular, like the recessed portion 12 of the first embodiment, and the size is preferably, for example, 50 μm or less, more preferably 30 μm or less in terms of a circular equivalent diameter. Particularly preferably, it is 20 μm or less. Moreover, it is preferable that the circular equivalent diameter of depression part 12 'is 5 micrometers or more. However, the depth of the depressed portion 12 ′ is 20% to 100% of the thickness of the protective layer 20, preferably 20% to 90%, and more preferably about 50% to 70%. In the case of the core-sheath-protective layer structure, even if the depressed portion 12 ′ reaches the sheath portion 11, the optical transmission function of the POF is not significantly impaired, but this is one purpose of providing a protective layer. In some cases, the effect of improving the resistance to repeated bending resistance of POF may be lowered. From this point, even in the case of the core-sheath-protective layer structure, it is desirable that the depressed portion 12 ′ does not reach the sheath portion 11 and is not too deep. . Further, if the depth of the depressed portion 12 ′ is too shallow, there is a possibility that a sufficient light leakage promoting effect cannot be obtained.
[0027]
In addition, in order to reduce the light absorption in the sheath part 11 and the protective layer 20 and increase the amount of light leakage from the POF side surface, the material of the sheath part 11 and the protective layer 20 covered by the core part 10 is transparent. It is particularly preferable to select a material that is superior to the above.
[0028]
When light is incident and guided from the end of the core-sheath POF having the protective layer 20 formed with the depression 12 'as described above, a part of the light in the core 10 is obtained. Proceeding to the sheath part 11, further proceeding to the protective layer 20, reaching the depressed part 12 'in the protective layer, and exiting into the depressed part 12', POF side light leakage is promoted.
[0029]
(Third embodiment)
FIG. 4 is a schematic cross-sectional view showing a configuration of an embodiment of a sea-island POF with a protective layer according to the present invention.
[0030]
In the present embodiment, a plurality of island portions 30 each having a core or core-sheath structure are used, and the plurality of island portions 30 are arranged in the sea portion 31 to protect the periphery so as to cover the sea portion 31. Layer 20 is formed.
[0031]
As a core and a sheath of the island part 30, what consists of the material similar to the core part and sheath part which were demonstrated in the said 1st Embodiment can be used. Moreover, as the sea part 31, what consists of the material similar to the sheath part demonstrated in the said 1st Embodiment and the protective layer demonstrated in the said 2nd Embodiment can be used. As the protective layer 20, a layer made of the same material as that described in the second embodiment can be used.
[0032]
The cross-sectional shape of the island part 30 is typically circular or hexagonal, and the diameter of the island part 30 is not particularly limited, but is preferably about 20 to 1000 μm. The number of island portions 30 is not particularly limited, but is preferably about 5 to 200, for example. The arrangement of the plurality of island portions 30 in the sea portion 31 is preferably substantially stacked as shown in FIG.
[0033]
In order to cause light leakage from the side surface of the POF (in this embodiment, the outer surface of the protective layer 20), as in the second embodiment, a large number of depressions 12 'are formed on the surface of the protective layer 20. .
[0034]
By using a material having a lower bending elastic modulus than the material of the island part 30 as the material of the sea part 31, the bending elastic modulus of the POF can be lowered and the flexibility can be improved.
[0035]
In addition, in order to reduce the light absorption in the sea part 31 and the protective layer 20 and to increase the amount of light leakage from the POF side surface, the material of the sea part 31 and the protective layer 20 surrounding the island part 30 is excellent in transparency. It is particularly preferred to select the material.
[0036]
When light is incident and guided to the POF having the sea-island structure having the protective layer 20 having the depressed portion 12 ′ as described above, a part of the light in the island portion 30 is obtained. Proceeding to the sea part 31, further proceeding to the protective layer 20, reaching the depressed part 12 ′ in the protective layer and emitting into the depressed part 12 ′, and POF side light leakage is promoted.
[0037]
The multi-core POF as described above has a small increase in light leakage from the fiber due to bending due to its structure, and even when applied to an application where it is bent so as to have a small radius of curvature, local light leakage at the bent portion. It is possible to perform illumination with little increase and excellent light leakage uniformity.
[0038]
(Fourth embodiment)
FIG. 5 is a schematic cross-sectional view showing an embodiment of a method for producing a POF according to the present invention. This figure particularly shows a process of forming a depression on the POF surface.
[0039]
In the present embodiment, fine particles are applied to the surface at high speed (jetting) while the fiber surface layer portion is softened, for example, during or immediately after the heat drawing process or heat treatment process in general plastic optical fiber manufacturing. The surface layer portion is cured after forming the depressed portion on the POF surface.
[0040]
As fine particles, it is possible to use quartz sand, glass beads or the like used when the surface of the resin or the like is treated, but such solid matter bites into or remains on the surface of the POF. It is not necessarily preferable for the injection of fine particles for forming the depression on the outer surface of the POF.
[0041]
Therefore, in the present embodiment, as the ejected fine particles, those made of a material that can be easily removed from the POF surface by evaporation or sublimation by heating or the like such as water, ice and dry ice are used. And when the injection | pouring microparticles | fine-particles which consist of these evaporable or sublimable materials are used, it is possible to make it act as a POF cooling refrigerant | coolant after a fiber heat processing process, and is convenient. In particular, water vapor (water), which can easily give energy to the fine particles that collide with the POF at a high speed and can simultaneously function as a heat source for softening the surface layer of the POF, is vaporizable for producing the POF of the present invention. It is particularly preferably used as a material, and the surface temperature of the POF is softened by uniformly spraying the entire surface of the POF at a water vapor temperature of about 100 ° C. to 150 ° C. under conditions near the saturated pressure where the water vapor is in a gas-liquid mixed state. And fine water droplets body It is possible to simultaneously perform the formation of the depressed portion of the surface by the collision.
[0042]
In FIG. 5, while the POF 40 having no depression on the surface is running upward so as to pass through the central portion of the porous cylinder 42, for example, from the outside of the porous cylinder to the inside of the porous cylinder through the numerous holes of the porous cylinder 42. Steam of about 120 ° C. is supplied by injection. The porous cylinder 42 is disposed in a steam heating furnace, and the flow resistance when the saturated pressurized steam supplied from the porous cylinder is discharged from both ends of the porous cylinder, or leakage of water vapor provided at both ends of the porous cylinder. Due to the pressure loss in the seal mechanism that prevents the pressure, the pressure is maintained against the atmospheric pressure.
[0043]
In the porous cylinder 42, the surface layer portion of the POF 40 is softened, and water vapor fine particles are formed on the surface. body The depression is formed by jetting. Thereby, the depression part is formed in the surface of POF40 which came out of the steam heating furnace, and the water fine particle injected here body Is removed by evaporation. At that time, the POF is cooled.
[0044]
Such fine particles body In the process of forming the depressed portion by injection, an external force is applied to the POF surface, and based on this, a birefringent structure is partially formed in the sheath portion 11 or the protective layer 20 where the depressed portions 12, 12 ′ are formed. Therefore, in addition to the light leakage promoting effect based on the surface shape of the depressions 12 and 12 ′, the light leakage promoting effect based on optical scattering by the birefringent structure is also added.
[0045]
In addition, since a large number of depressions 12 and 12 'having a uniform distribution that can be regarded as pseudo flaws are formed on the surface, and a large amount of light leakage can be generated from these portions, before and after the depression formation. Even if the surface of the POF 40 is damaged by spinning, post-treatment, processing, etc., the light leakage from the damaged portion is mixed with the light leakage from the depressed portion, so that it is not visually recognized as a remarkable bright spot.
[0046]
(Fifth embodiment)
FIG. 6 is a partial cross-sectional perspective view showing an embodiment of a lighting device using a POF according to the present invention.
[0047]
A plurality of (for example, 20 to 100) POFs 40 as in the first to third embodiments or the POFs 40 obtained in the fourth embodiment are bundled to have a light transmitting property (preferably transparent). The illuminating body 46 is formed by being housed in the conductive tube 44, and the primary light source 48 is disposed so as to face at least one end surface of the illuminating body 46. Thereby, an illuminating device is obtained. The plurality of POFs 40 may be arranged in parallel to each other, or may be twisted in an appropriate form.
[0048]
As the light-transmitting and flexible tube 44, for example, a tube made of vinyl chloride resin or polyethylene having a thickness of about 1 mm can be used. The length of the tube 44 can be sufficiently about 30 m. As the light source 48, a known light source can be used, but a light source having a large light amount such as a halogen lamp, a metal halide lamp, or a high-pressure mercury lamp is preferably used.
[0049]
When manufacturing a lighting device according to this embodiment, when a bundle of a plurality of POFs 40 is inserted into the tube 44, the surface of the POF 40 has a number of depressions, so that the POF has a satin finish. The frictional resistance at the time of contact between each other or between the POF and the tube inner surface is low, damage due to rubbing between the POFs or between the POF and the tube inner surface can be reduced, and the POF can be easily inserted into the tube.
[0050]
Furthermore, in order to promote light leakage, it is better to twist the POF in the tube. However, in this embodiment, since the light leakage promoting effect based on the depression is sufficiently large, it is not necessary to twist the POF. It becomes easier to load POF inside.
[0051]
In the illumination device of the present embodiment, a considerable portion of the light transmitted through each POF can be extracted to the outside due to the light leakage promoting effect due to the depression on the POF surface, and the amount of light leakage along the longitudinal direction of the POF The uniformity of distribution is good, and defects such as specific bright spots and light intensity spots can be reduced.
[0052]
【Example】
The present invention will be specifically described below with reference to examples. In the examples, “parts” means parts by weight.
[0053]
[Example 1]
As shown in FIG. 1, polymethylmethacrylate is used as the material for the core, and a copolymer of vinylidene fluoride / tetrafluoroethylene = 72/28 (parts) is used as the material for the sheath. A POF having a core-sheath structure as described above was produced.
[0054]
That is, first, the core material resin and the sheath material resin are passed through a melt extruder set at a temperature of 220 ° C. and a metering gear metering pump into a two-layer composite spinning nozzle used for ordinary POF spinning. Then, it was discharged from the composite spinning nozzle, taken up at a constant speed, and subsequently heated and stretched twice using a hot air heating furnace at 140 ° C. to obtain a POF having a normal core-sheath structure. The outer diameter of POF was about 1000 μm, and the layer thickness of the sheath was about 6 μm.
[0055]
Next, the normal POF obtained as described above is passed through a steam heating furnace in which sealing mechanisms are provided at both ends and a porous cylinder is arranged on the outer periphery of the POF passage part, and the internal pressure of the steam heating furnace is reduced. The absolute pressure is maintained at 0.2 Mpa, and water vapor of 120 ° C. is injected and supplied to the outer surface of the POF through the hole of the porous cylinder, and the circular converted diameter is about 10 μm from the surface to the surface of the POF sheath. A large number of substantially mortar-shaped depressions having a depth of about 3 μm were formed to obtain a POF as shown in FIG. On the side of the POF, the area ratio occupied by the depression was about 50%.
[0056]
60 POFs were bundled in parallel with each other, and housed in a transparent vinyl chloride resin tube having an outer diameter of 12 mm, an inner diameter of 10 mm, and a length of 20 m, to produce a lighting body. The POF storage operation was easy, and there was no difficulty in insertion due to friction between the tube inner surface and the POF.
[0057]
A light source is arranged facing both ends of the illuminating body (both ends of the POF bundle), light emitted from the light source is incident on each POF, light is guided through each POF, and light is leaked from the side surfaces of the POF. When light was leaked from the side of the tube, there was almost no unevenness in the lengthwise direction, and no specific bright spot was observed.
[0058]
[Example 2]
Polymethyl methacrylate is used as the material for the core, and 2,2,2-trifluoroethyl methacrylate (3FM) / 2- (perfluorooctyl) ethyl methacrylate (17FM) / methyl methacrylate (MMA) is used as the material for the sheath. / A copolymer of methacrylic acid (MAA) = 51/30/18/1 (part), and a copolymer of vinylidene fluoride / tetrafluoroethylene = 72/28 (part) as a material for the protective layer. The core-sheath-protective layer structure POF as shown in FIG. 2 was produced as follows.
[0059]
That is, first, in the same manner as in Example 1 except that the core material resin, the sheath material resin, and the protective layer material resin were supplied to a three-layer composite spinning nozzle used for normal POF spinning, POF having a core-sheath-protective layer structure was obtained. The outer shape of the POF was about 1000 μm, and the layer thickness of the sheath and the layer thickness of the protective layer were both about 5 μm.
[0060]
Next, the normal POF obtained as described above was treated in the same manner as in Example 1, and the surface of the protective layer of POF had an approximately mortar shape with a circular equivalent diameter of about 10 μm and a depth of about 3 μm from the surface. A large number of depressions were formed, and a POF as shown in FIG. 3 was obtained. On the side of the POF, the area ratio occupied by the depression was about 50%.
[0061]
60 POFs were bundled in parallel with each other, and housed in a transparent vinyl chloride resin tube having an outer diameter of 12 mm, an inner diameter of 10 mm, and a length of 20 m, to produce a lighting body. The POF storage operation was easy, and there was no difficulty in insertion due to friction between the tube inner surface and the POF.
[0062]
A light source is arranged facing both ends of the illuminating body (both ends of the POF bundle), light emitted from the light source is incident on each POF, light is guided through each POF, and light is leaked from the side surfaces of the POF. When light was leaked from the side of the tube, there was almost no unevenness in the lengthwise direction, and no specific bright spot was observed.
[0063]
Example 3
Polymethylmethacrylate (PMMA) is used as the material for the core (island), and a copolymer of vinylidene fluoride / tetrafluoroethylene = 72/28 (parts) is used as the material for the sea and the protective layer. Then, a POF having a sea-island structure as shown in FIG. 3 was manufactured as follows. In addition, a material having a lower melt viscosity at the same temperature as the sea part material was used as the protective layer material.
[0064]
That is, as a composite spinning nozzle, 37 inner layers (hole diameter 1.0 mm) / outer layer (a trumpet shape spreading from a hole diameter 1.1 mm to a hole diameter 2.3 mm) in a cross section of φ20 mm are stacked in a stack of 37 nozzles. It has a structure that is arranged almost evenly, has a funnel-shaped throttle part with an inlet diameter of φ20 mm and a discharge hole diameter of φ4 mm below the outer layer nozzle hole, and a protective layer material introduction part on the outer peripheral side surface of the inlet part of the throttle part The installed structure was used. Then, the core material resin is introduced into the inner layer nozzle, the sea portion material resin is supplied to the outer layer nozzle, the protective layer material resin is introduced into the protective layer material introduction portion, and discharged from each outer layer nozzle below the outer layer nozzle. The sea part material resin to be fused is discharged from the composite spinning nozzle, taken out at a constant speed, and heated twice using a 140 ° C. hot air heating furnace, and the island part is made of only PMMA. A normal sea-island POF having 37 islands having a protective layer on the outer periphery was produced. The outer diameter of POF was 1000 μm, the diameter of the island portion was about 150 μm, and the thickness of the protective layer was about 5 μm.
[0065]
Next, the POF obtained as described above is treated in the same manner as in Example 1, and the surface of the protective layer of POF has a substantially mortar shape having a circular equivalent diameter of about 10 μm and a depth of about 3 μm from the surface. Many depressions were formed, and a POF as shown in FIG. 4 was obtained. On the side of the POF, the area ratio occupied by the depression was about 50%.
[0066]
60 POFs were bundled in parallel with each other, and housed in a transparent vinyl chloride resin tube having an outer diameter of 12 mm, an inner diameter of 10 mm, and a length of 20 m, to produce a lighting body. The POF storage operation was easy, and there was no difficulty in insertion due to friction between the tube inner surface and the POF.
[0067]
A light source is arranged facing both ends of the illuminating body (both ends of the POF bundle), light emitted from the light source is incident on each POF, light is guided through each POF, and light is leaked from the side surfaces of the POF. When light was leaked from the side of the tube, there was almost no unevenness in the lengthwise direction, and no specific bright spot was observed.
[0068]
【The invention's effect】
As described above, the optical fiber of the present invention has good uniformity of side light leakage without unevenness in the amount of light over the entire length direction, and even if the surface of the optical fiber is slightly damaged, the damaged part is a bright spot or bright line. It is difficult to see as. In addition, since the optical fiber of the present invention has a small frictional resistance on the surface, it is easy to bundle a plurality and store them in a transparent tube, and an illumination device can be easily manufactured using this.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a configuration of an embodiment of a plastic optical fiber (POF) having a core-sheath two-layer structure according to the present invention.
FIG. 2 is a development view of the surface of the sheath portion of the plastic optical fiber (POF) of the embodiment of FIG. 1;
FIG. 3 is a schematic cross-sectional view showing a configuration of an embodiment of a plastic optical fiber (POF) having a three-layer structure of a core-sheath-protective layer according to the present invention.
FIG. 4 is a schematic cross-sectional view showing a configuration of an embodiment of a sea-island structure plastic optical fiber (POF) with a protective layer according to the present invention.
FIG. 5 is a schematic cross-sectional view showing an embodiment of a method for producing a plastic optical fiber (POF) according to the present invention.
FIG. 6 is a partial cross-sectional perspective view showing an embodiment of a lighting device using a plastic optical fiber (POF) according to the present invention.
[Explanation of symbols]
10: Core part
11: sheath
12, 12 ': depression
20: Protective layer
30: Island
31: Kaifu
40: Plastic optical fiber (POF)
42: perforated tube
44: Translucent flexible tube
46: Lighting body
48: Light source

Claims (1)

芯−鞘構造のプラスチック光ファイバの鞘部の表面に、該鞘部の層厚の20%〜90%の深さで複数個の陥没部が形成されているプラスチック光ファイバ、または、芯−鞘構造または海−島構造の外周部に保護層を有するプラスチック光ファイバの保護層の表面に、該保護層の層厚の20%〜100%の深さで複数個の陥没部が形成されているプラスチック光ファイバを製造する方法であって、
(a)芯−鞘構造のプラスチック光ファイバ、(b)芯−鞘構造の外周部に保護層を有するプラスチック光ファイバ、または(c)海−島構造の外周部に保護層を有するプラスチック光ファイバの軟化状態の表層部に蒸発性または昇華性の微小粒体を噴射することで前記(a),(b)または(c)のプラスチック光ファイバの表面に複数の陥没部を形成し、該陥没部内の前記蒸発性または昇華性の微小粒体を蒸発または昇華させ、前記プラスチック光ファイバの表層部を硬化させることを特徴とする、プラスチック光ファイバの製造方法。
A plastic optical fiber in which a plurality of depressions are formed on the surface of a sheath portion of a plastic optical fiber having a core-sheath structure at a depth of 20% to 90% of the layer thickness of the sheath portion, or a core-sheath On the surface of the protective layer of the plastic optical fiber having a protective layer on the outer periphery of the structure or the sea-island structure, a plurality of depressions are formed at a depth of 20% to 100% of the thickness of the protective layer. A method of manufacturing a plastic optical fiber , comprising:
(A) Plastic optical fiber having a core-sheath structure, (b) Plastic optical fiber having a protective layer on the outer periphery of the core-sheath structure, or (c) Plastic optical fiber having a protective layer on the outer periphery of the sea-island structure A plurality of depressions are formed on the surface of the plastic optical fiber of (a), (b) or (c) by injecting evaporating or sublimating fine particles onto the softened surface layer of A method for producing a plastic optical fiber, comprising evaporating or sublimating the evaporable or sublimable fine particles in the section to cure a surface layer portion of the plastic optical fiber.
JP28322699A 1999-10-04 1999-10-04 PLASTIC OPTICAL FIBER, MANUFACTURING METHOD THEREOF, AND LIGHTING DEVICE USING THE PLASTIC OPTICAL FIBER Expired - Lifetime JP4216418B2 (en)

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US8967845B2 (en) * 2013-01-11 2015-03-03 Corning Incorporated Light diffusing optical fiber bundles, illumination systems including light diffusing optical fiber bundles, and methods of affixing light diffusing optical fiber bundles to polymer optical fibers
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