JPH05229847A - Production of fluoride glass rod - Google Patents
Production of fluoride glass rodInfo
- Publication number
- JPH05229847A JPH05229847A JP16543492A JP16543492A JPH05229847A JP H05229847 A JPH05229847 A JP H05229847A JP 16543492 A JP16543492 A JP 16543492A JP 16543492 A JP16543492 A JP 16543492A JP H05229847 A JPH05229847 A JP H05229847A
- Authority
- JP
- Japan
- Prior art keywords
- mold
- funnel
- glass
- ingot mold
- melt
- 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.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/012—Manufacture of preforms for drawing fibres or filaments
- C03B37/01265—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt
- C03B37/01268—Manufacture of preforms for drawing fibres or filaments starting entirely or partially from molten glass, e.g. by dipping a preform in a melt by casting
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B2201/00—Type of glass produced
- C03B2201/80—Non-oxide glasses or glass-type compositions
- C03B2201/82—Fluoride glasses, e.g. ZBLAN glass
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は２〜６μｍ帯の赤外線を
伝送することができるフッ化物ガラス光ファイバ用母材
に使用されるフッ化物ガラスロッドの製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a fluoride glass rod used as a base material for a fluoride glass optical fiber capable of transmitting infrared rays in the band of 2 to 6 μm.
【０００２】[0002]
【従来の技術】近年、光ファイバを使用した光通信シス
テムの進歩にはめざましいものがある。光通信システム
は他の通信システムに比べて中継距離を長くとれ、電磁
誘導雑音対策が不要であり、高密度な情報を遠方に伝搬
できる等の利点を有しているため、徐々に他の通信シス
テムに代わりつつある。2. Description of the Related Art In recent years, the progress of optical communication systems using optical fibers has been remarkable. Compared to other communication systems, the optical communication system has a long relay distance, does not require countermeasures against electromagnetic induction noise, and has the advantage that high-density information can be propagated to a long distance. It is replacing the system.
【０００３】このような光通信に用いられる光ファイバ
の開発においても、光の伝送損失を低減するために、光
ファイバのコアおよびクラッドの材料開発、ならびに発
光、受光素子等の光素子の開発がさかんに進められてい
る。Also in the development of optical fibers used for such optical communication, in order to reduce light transmission loss, development of materials for cores and claddings of optical fibers and development of optical elements such as light emitting and light receiving elements. It is being actively promoted.
【０００４】現在、光通信システムに使用されている光
ファイバは、石英ガラスを材料とし、光の波長は0.85μ
ｍ帯の短波長帯と 1.3μｍ帯の長波長帯を用いている。The optical fiber currently used in the optical communication system is made of quartz glass and has a light wavelength of 0.85 μm.
A short wavelength band of m band and a long wavelength band of 1.3 μm are used.
【０００５】ところで、光ファイバの光損失は、ガラス
物質および不純物の光散乱や光吸収によるものである。
光散乱による光損失は、物質の種類にあまり影響せず、
使用する光の波長の４乗に逆比例することが知られてい
る。このため紫外線等の短波長域での光ファイバの使用
することは難しいと言われている。The optical loss of the optical fiber is due to the light scattering and light absorption of the glass substance and impurities.
Light loss due to light scattering does not significantly affect the type of substance,
It is known to be inversely proportional to the fourth power of the wavelength of the light used. Therefore, it is said that it is difficult to use an optical fiber in a short wavelength region such as ultraviolet rays.
【０００６】一方、使用する波長が長くなると散乱によ
る損失が急激に小さくなるが、逆に吸収損失が増す。こ
のような吸収損失は、光が物質に当たったときの分子の
格子振動によるものであるため、この損失を低減するに
は、物質が振動し難いように重い分子で構成されかつ弱
い力で結合されているような材料を使用することが好適
である。On the other hand, when the wavelength used becomes longer, the loss due to scattering sharply decreases, but on the contrary, the absorption loss increases. Such absorption loss is due to lattice vibration of molecules when light hits a substance.To reduce this loss, therefore, the substance is composed of heavy molecules so that it is difficult for the substance to vibrate and is bound by a weak force. It is preferred to use materials such as those mentioned.
【０００７】従って、光ファイバの光損失を低減するに
は、従来の光の波長より長い波長の光を光源に用い、か
つ吸収損失の低い材料を使用することが要望されてい
る。このような吸収損失の低い材料として、フッ化物ガ
ラスおよびハライド結晶等が知られており、その理論的
伝送損失は特定波長域において現在使用されている石英
ファイバの 100分の１と非常に小さい。特に、このフッ
化物ガラスが通信用赤外線光ファイバとして最も期待さ
れ、さかんに研究されている。Therefore, in order to reduce the optical loss of the optical fiber, it is required to use light having a wavelength longer than that of conventional light as a light source and to use a material having a low absorption loss. Fluoride glass and halide crystals are known as such materials having low absorption loss, and their theoretical transmission loss is extremely small, which is one-hundredth that of silica fibers currently used in a specific wavelength range. In particular, this fluoride glass is most promising as an infrared optical fiber for communication, and has been extensively studied.
【０００８】このようなフッ化物ガラスからなる赤外線
光ファイバを製造するにあたっては、まず光ファイバの
母材となるガラスロッドを製造する必要がある。フッ化
物ガラスからなる赤外線光ファイバ用のガラスロッドを
製造するには、フッ化物ガラスの構成原料を調製し、そ
れらを金製またはガラス質カーボン製のルツボに投入
し、電気炉中で加熱溶融後、金属製鋳型に融液を注入し
た後、急冷する方法を用いていた。When manufacturing an infrared optical fiber made of such a fluoride glass, it is first necessary to manufacture a glass rod which is a base material of the optical fiber. To manufacture a glass rod for infrared optical fiber made of fluoride glass, prepare the constituent materials of fluoride glass, put them in a crucible made of gold or vitreous carbon, and heat and melt them in an electric furnace. The method of injecting the melt into a metal mold and then quenching was used.
【０００９】[0009]
【発明が解決しようとする課題】上記のような従来の方
法においては、単にガラス融液を鋳型に注入すると、融
液の乱流のため気泡を巻き込み、融溶ガラスが凝固した
後に欠陥として残るため、このようなガラスロッドを母
材とする光ファイバの光伝送に悪影響を与えていた。In the conventional method as described above, when the glass melt is simply injected into the mold, bubbles are entrained due to the turbulent flow of the melt and remain as defects after the melted glass is solidified. Therefore, it adversely affects the optical transmission of an optical fiber using such a glass rod as a base material.
【００１０】上記のようなガラスロッドにおける欠陥の
残留という問題に対処するものとして、例えば、特公昭
60−251140号に記載されているように、鋳型もしくは鋳
型の働きをするガラス管を長手方向の軸を回転軸として
回転させながら融液を注入する方法が知られている。As a means for dealing with the problem of residual defects in the glass rod as described above, for example, Japanese Patent Publication No.
As described in 60-251140, there is known a method of injecting a melt while rotating a mold or a glass tube functioning as a mold with a longitudinal axis as a rotation axis.
【００１１】しかしながら、この方法では回転数を約30
00rpm とかなり高速で回転させなければならず、回転軸
にわずかなずれが生ずると、円筒軸に対称で均質なガラ
スロッドが得られないという問題があった。However, in this method, the rotation speed is about 30.
It had to be rotated at a considerably high speed of 00 rpm, and if there was a slight deviation in the rotation axis, there was the problem that a glass rod that was symmetric with respect to the cylindrical axis could not be obtained.
【００１２】そこで本発明の目的は、鋳型を回転させる
ことなく、ガラスロッドでの欠陥の発生を抑制するフッ
化物ガラスロッドの製造方法を提供することにある。Therefore, an object of the present invention is to provide a method for producing a fluoride glass rod which suppresses the generation of defects in the glass rod without rotating the mold.
【００１３】[0013]
【課題を解決するための手段】本発明者等は上記問題点
を解決するために鋭意研究・検討した結果、低湿度He雰
囲気中において鋳型にガラス原料を流し込むことによっ
て欠陥の少ないフッ化物ガラスロッドを製造できること
を見出した。Means for Solving the Problems As a result of intensive research and study by the present inventors in order to solve the above problems, a fluoride glass rod having few defects by pouring a glass raw material into a mold in a low humidity He atmosphere It has been found that can be manufactured.
【００１４】すなわち、本発明に従うと、溶融したフッ
化物ガラス原料を、ガラス転移温度付近の温度に予備加
熱した筒状鋳型に流し込む工程を含むフッ化物ガラスロ
ッドの製造方法において、低湿度He雰囲気下で、鋳型の
底部まで挿入できる直管部を有する漏斗を使用して、溶
融したフッ化物ガラス原料を、該溶融フッ化物ガラス原
料が雰囲気ガスを巻き込まないよう前記筒状鋳型に流し
込み、該溶融フッ化物ガラス原料が前記鋳型内に装入さ
れるに従って、前記漏斗を上方に引上げながら該筒状鋳
型を該溶融フッ化物ガラス原料で満たすことを特徴とす
るフッ化物ガラスロッドの製造方法が提供される。That is, according to the present invention, in a method for producing a fluoride glass rod, which comprises a step of pouring a molten fluoride glass raw material into a cylindrical mold preheated to a temperature near the glass transition temperature, in a low humidity He atmosphere. Then, using a funnel having a straight pipe part that can be inserted to the bottom of the mold, the molten fluoride glass raw material is poured into the cylindrical mold so that the molten fluoride glass raw material does not entrain atmospheric gas, and the molten fluoride glass raw material is melted. Provided is a method for producing a fluoride glass rod, which comprises filling the tubular mold with the molten fluoride glass raw material while pulling up the funnel as the fluoride glass raw material is charged into the mold. ..
【００１５】上記低湿度He雰囲気としては、できるだけ
高純度のHeガスを、少なくともガラス原料を注入してい
る鋳型の近傍に流し込むか、より好ましくは、気密性容
器内に高純度Heガスを充満させて上記の操作を行なわせ
ることで達成される。As the low-humidity He atmosphere, a He gas having a purity as high as possible is poured at least in the vicinity of the mold into which the glass raw material is injected, or more preferably, the airtight container is filled with the high-purity He gas. This is achieved by performing the above operation.
【００１６】低湿度He雰囲気としては、水分が 2.5 ppm
以下（水分露点−70℃以下）のHe雰囲気を使用するのが
好ましく、さらに低湿度を保証するにはHeガスを−80℃
以下に冷却するのが好ましい。As a low humidity He atmosphere, the water content is 2.5 ppm.
It is preferable to use a He atmosphere with a moisture dew point below -70 ° C, and to ensure low humidity, use He gas at -80 ° C.
It is preferable to cool to the following.
【００１７】さらに本発明のフッ化物ガラスロッドの製
造方法で用いる鋳型としては、グラファイト製あるいは
金属製であって、該鋳型の筒軸にほぼ平行に２以上に分
割し得る構造を有するのものが好ましい。鋳型の形状と
しては、通常は円筒型が用いられる。Further, as the mold used in the method for producing a fluoride glass rod of the present invention, a mold made of graphite or metal and having a structure capable of being divided into two or more parts substantially parallel to the cylinder axis of the mold is used. preferable. As the shape of the mold, a cylindrical type is usually used.
【００１８】図１は本発明に用いる鋳型の一具体例であ
って、この鋳型全体が覆われる加熱容器に挿入して使用
するものである。図１(a)は該鋳型の部分的に断面で示
した側面図であり、図１(b)は右半分を断面で示した平
面図である。図１(a)および(b)に示す如く、この鋳型
は、２つの半円筒形の鋳型部品をネジで接合した、全体
として一方が開口した円筒形をなす。すなわち、第２図
(b)に示すように、円筒軸に平行に鋳型１が２分割され
た鋳型部品が互いにボルトにより結合されている。FIG. 1 shows a specific example of the mold used in the present invention, which is used by inserting it into a heating container which covers the entire mold. FIG. 1 (a) is a side view partially showing the mold in cross section, and FIG. 1 (b) is a plan view showing the right half in cross section. As shown in FIGS. 1 (a) and 1 (b), this mold has a cylindrical shape in which one semi-cylindrical mold part is joined with a screw and one side is opened as a whole. That is, FIG.
As shown in (b), the mold parts obtained by dividing the mold 1 in two parallel to the cylinder axis are connected to each other by bolts.
【００１９】図２は本発明の方法に好ましく使用される
漏斗の概略図である。この漏斗６は、鋳型１の底部に到
達する長さの直管部７を備えている。すなわち、溶融し
たフッ化物ガラス原料を鋳型１に流し込む際に、鋳型１
の底部まで直管部７を挿入しながら漏斗６を鋳型１内に
配置し、漏斗６内に溶融したフッ化物ガラス原料を流し
込む。従って、ガラス原料は直管部７を介して静かに鋳
型１の底部に注がれる。ついで、ガラス原料を注ぐに従
い漏斗６を上方に徐々に引き上げてゆき、ガラス融液を
注ぎ終わるまでに漏斗６の直管部７を鋳型中空部の最上
部まで引き上げ、最終的に直管部７が溶融したガラス原
料から引き抜けるように注意しながら注入操作を実施す
る。FIG. 2 is a schematic view of a funnel preferably used in the method of the present invention. The funnel 6 includes a straight pipe portion 7 having a length that reaches the bottom of the mold 1. That is, when the molten fluoride glass raw material is poured into the mold 1, the mold 1
The funnel 6 is placed in the mold 1 while the straight pipe portion 7 is inserted to the bottom of the mold 1, and the molten fluoride glass raw material is poured into the funnel 6. Therefore, the glass raw material is gently poured into the bottom of the mold 1 through the straight pipe portion 7. Then, as the glass raw material is poured, the funnel 6 is gradually pulled upward, and the straight pipe portion 7 of the funnel 6 is pulled up to the top of the hollow portion of the mold until the glass melt is completely poured, and finally the straight pipe portion 7 The pouring operation is carried out while being careful to pull out from the molten glass raw material.
【００２０】[0020]
【作用】本発明は、鋳型に溶融ガラス原料を流し込む工
程を低湿度He雰囲気下で鋳型の底部まで挿入できる直管
部を有する漏斗を使用して行なうことを特徴としてい
る。従来、この工程は大気中で行なわれているので、溶
融ガラス原料を鋳型に注入する際に気泡をまき込みやす
く、このため得られたガラスロッド中に欠陥が残ってし
まう。The present invention is characterized in that the step of pouring the molten glass raw material into the mold is performed by using a funnel having a straight pipe portion that can be inserted to the bottom of the mold under a low humidity He atmosphere. Conventionally, since this step is performed in the atmosphere, bubbles are likely to be introduced into the glass rod when the molten glass raw material is injected into the mold, and defects are left in the obtained glass rod.
【００２１】しかしながら、本発明で使用するHeガスは
溶融ガラス原料に対する透過性が高いのでガラス原料が
固化する前に融液の液面方向に浮上して、固化したガラ
ス内には気泡が殆ど残留することはなくなる。従って、
欠陥の少ない光ファイバの製造に好適な光ファイバロッ
ドを製造することができる。However, since the He gas used in the present invention has high permeability to the molten glass raw material, it floats in the liquid surface direction of the melt before the glass raw material is solidified, and almost no bubbles remain in the solidified glass. There is nothing to do. Therefore,
An optical fiber rod suitable for manufacturing an optical fiber with few defects can be manufactured.
【００２２】また従来、フッ化物ガラスからなる光ファ
イバにおいて、ガラス中の不純物であるＯＨ基による吸
収損失が問題となっており、さらにＯＨ基はガラス成分
と反応して水酸化物を発生させることが知られておりこ
のようなＯＨ基を低減することが要望されていた。本発
明によると、Heガス、特に低湿度Heを使用するので、Ｏ
Ｈ基の発生源である水分の混入を抑制し、ＯＨ基による
吸収損失の少ないフッ化物ガラス光ファイバを得ること
が可能となる。Conventionally, in an optical fiber made of a fluoride glass, absorption loss due to an OH group which is an impurity in the glass has been a problem, and further, the OH group reacts with a glass component to generate a hydroxide. However, it has been desired to reduce such OH groups. According to the present invention, since He gas, especially low-humidity He is used,
It is possible to obtain a fluoride glass optical fiber that suppresses the mixing of water, which is a generation source of H groups, and has a small absorption loss due to OH groups.
【００２３】本発明の方法では、図２に示したような鋳
型の底部まで挿入できる直管部を有する漏斗を使用して
溶融したフッ化物ガラス原料を鋳型に流し込む。このよ
うな漏斗の使用により雰囲気中のHeの巻き込みが少なく
なり、原料中に気泡が発生し難くなり、He雰囲気中で注
入を行う効果がより有効となる。In the method of the present invention, the molten fluoride glass raw material is poured into the mold using a funnel having a straight pipe portion which can be inserted to the bottom of the mold as shown in FIG. By using such a funnel, the inclusion of He in the atmosphere is reduced, bubbles are less likely to be generated in the raw material, and the effect of performing the injection in the He atmosphere becomes more effective.
【００２４】さらに本発明の一態様に従うと、使用する
鋳型はグラファイト製あるいは金属製であって、円筒軸
に平行に図１に示すような２個あるいは２以上に分割し
得る構造を有する。このような構造を有することによ
り、鋳型を分割することによりガラスロッドに損傷を与
えることなく、容易に取り出すことが可能となる。Further, according to one embodiment of the present invention, the mold used is made of graphite or metal and has a structure capable of being divided into two or more as shown in FIG. 1 in parallel with the cylindrical axis. With such a structure, it is possible to take out the glass rod easily by dividing the mold without damaging the glass rod.
【００２５】[0025]
【実施例】49ZrＦ4 −25BaＦ2 − 3.5LaＦ3 −２ＹＦ3
− 2.5AlＦ3 −18LiＦからなる組成(mol％）のフッ化物
ガラスファイバ用母材の製造を目的とし、上記組成とな
るように各成分を調製し、混合した原料20ｇを金るつぼ
に投入しフタをした。この金るつぼを石英製炉芯管内に
おいて 110℃で２時間乾燥させた後、昇温し、 850℃２
時間にわたってガラス融液を加熱保持し、続いて 800℃
まで降温した。[Example] 49ZrF 4 -25BaF 2 -3.5LaF 3 -2YF 3
For the purpose of manufacturing a base material for a fluoride glass fiber having a composition (mol%) composed of −2.5AlF 3 −18LiF, each component was prepared so as to have the above composition, and 20 g of the mixed raw material was put into a gold crucible and the lid was closed. Did. This gold crucible was dried in a quartz furnace core tube at 110 ° C for 2 hours and then heated to 850 ° C 2
Hold glass melt over time, then 800 ° C
The temperature dropped to.
【００２６】高純度He雰囲気中において、あらかじめ加
熱容器内に挿入して 260℃に予加熱した図１に示すよう
な構造の真鍮製鋳型１を垂直に立てて乾燥Heガス中で、
図２に示すような金製の漏斗６をして使用して金るつぼ
内のガラス融液を一定流量で流し込んだ。この際、最初
に漏斗６の直管部７を鋳型の底部まで差込み、その後ガ
ラス融液を注ぐに従い上方に徐々に引き上げてゆき、ガ
ラス融液が注ぎ終わるまでに直管部７を鋳型中空部の最
上部に位置するようにし、最終的に直管部７が融液より
引き抜けるように注意しながら注入した。In a high-purity He atmosphere, a brass mold 1 having a structure as shown in FIG. 1 which was previously inserted into a heating container and preheated to 260 ° C. was vertically set up in dry He gas,
The glass melt in the gold crucible was poured at a constant flow rate using a gold funnel 6 as shown in FIG. At this time, first insert the straight pipe part 7 of the funnel 6 to the bottom of the mold, and then gradually pull it upward as the glass melt is poured, until the glass melt finishes pouring the straight pipe part 7 into the mold hollow part. It was placed at the uppermost part of the above, and was poured while paying attention so that the straight pipe part 7 could finally be pulled out from the melt.
【００２７】その後、鋳型温度を 250℃とし２時間アニ
ール処理した。アニール処理後、炉の温度を室温まで下
げて、鋳型１よりガラスロッドを取り出した所、φ 8.5
× 100mmの気泡のない均質なガラスロッドが得られた。
このようにして得られたガラスロッドの側面を精密研磨
し、洗浄した後、テフロンＦＥＰでジャケットして光フ
ァイバ用ガラス母材を作製した。Thereafter, the mold temperature was set to 250 ° C. and annealing was performed for 2 hours. After the annealing treatment, the temperature of the furnace was lowered to room temperature, and the glass rod was taken out from the mold 1.
A 100 mm bubble-free homogeneous glass rod was obtained.
The side surface of the glass rod thus obtained was precisely polished, washed, and then jacketed with Teflon FEP to prepare a glass preform for optical fibers.
【００２８】[0028]
【発明の効果】本発明の製造方法によれば、不純物、特
にＯＨ基の混入が少なく、かつ気泡等の欠陥の発生を抑
えた均質なフッ化物ガラス母材を得ることができる。According to the manufacturing method of the present invention, it is possible to obtain a homogeneous fluoride glass base material in which impurities, particularly OH groups, are less mixed and the occurrence of defects such as bubbles is suppressed.
【００２９】従って、本発明の製造方法を光ファイバの
製造工程に導入することにより、光吸収損失の少ない高
品質な光ファイバを製造することが可能となる。Therefore, by introducing the manufacturing method of the present invention into the manufacturing process of an optical fiber, it becomes possible to manufacture a high-quality optical fiber with less light absorption loss.
【図１】本発明の製造方法に用いる円筒型鋳型の一具体
例であり、図１(a)はその側面図であり、図１(b)は断面
図である。FIG. 1 is a specific example of a cylindrical mold used in the manufacturing method of the present invention, FIG. 1 (a) is a side view thereof, and FIG. 1 (b) is a sectional view.
【図２】本発明の製造方法に使用される直管部を備えた
漏斗の斜視図である。FIG. 2 is a perspective view of a funnel having a straight pipe portion used in the manufacturing method of the present invention.
１ 鋳型 ６ 漏斗 ７ 漏斗の直管部 1 Mold 6 Funnel 7 Funnel straight section
Claims (1)
転移温度付近の温度に予備加熱した筒状鋳型に流し込む
工程を含むフッ化物ガラスロッドの製造方法において、
低湿度He雰囲気下で、鋳型の底部まで挿入できる直管部
を有する漏斗を使用して、溶融したフッ化物ガラス原料
を、該溶融フッ化物ガラス原料が雰囲気ガスを巻き込ま
ないよう前記筒状鋳型に流し込み、該溶融フッ化物ガラ
ス原料が前記鋳型内に装入されるに従って、前記漏斗を
上方に引上げながら該筒状鋳型を該溶融フッ化物ガラス
原料で満たすことを特徴とするフッ化物ガラスロッドの
製造方法。1. A method for producing a fluoride glass rod, comprising the step of pouring a molten fluoride glass raw material into a cylindrical mold preheated to a temperature near the glass transition temperature,
Under a low humidity He atmosphere, using a funnel having a straight pipe portion that can be inserted to the bottom of the mold, the molten fluoride glass raw material, in the tubular mold so that the molten fluoride glass raw material does not entrain atmospheric gas Production of a fluoride glass rod, characterized by pouring and filling the tubular mold with the molten fluoride glass raw material while pulling the funnel upward as the molten fluoride glass raw material is charged into the mold. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16543492A JPH0788235B2 (en) | 1992-06-01 | 1992-06-01 | Fluoride glass rod manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16543492A JPH0788235B2 (en) | 1992-06-01 | 1992-06-01 | Fluoride glass rod manufacturing method |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26836886A Division JPS63123826A (en) | 1986-11-11 | 1986-11-11 | Production of preform for fluoride glass |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05229847A true JPH05229847A (en) | 1993-09-07 |
| JPH0788235B2 JPH0788235B2 (en) | 1995-09-27 |
Family
ID=15812359
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP16543492A Expired - Fee Related JPH0788235B2 (en) | 1992-06-01 | 1992-06-01 | Fluoride glass rod manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0788235B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006263629A (en) * | 2005-03-25 | 2006-10-05 | Shimizu Corp | Apparatus for removing pollutant |
-
1992
- 1992-06-01 JP JP16543492A patent/JPH0788235B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006263629A (en) * | 2005-03-25 | 2006-10-05 | Shimizu Corp | Apparatus for removing pollutant |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0788235B2 (en) | 1995-09-27 |
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