JPS6283325A - Production of quartz glass having high purity - Google Patents
Production of quartz glass having high purityInfo
- Publication number
- JPS6283325A JPS6283325A JP22279985A JP22279985A JPS6283325A JP S6283325 A JPS6283325 A JP S6283325A JP 22279985 A JP22279985 A JP 22279985A JP 22279985 A JP22279985 A JP 22279985A JP S6283325 A JPS6283325 A JP S6283325A
- Authority
- JP
- Japan
- Prior art keywords
- quartz glass
- base material
- porous
- parent material
- porous quartz
- 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
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
- C03B37/01446—Thermal after-treatment of preforms, e.g. dehydrating, consolidating, sintering
-
- 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
- C03B37/014—Manufacture of preforms for drawing fibres or filaments made entirely or partially by chemical means, e.g. vapour phase deposition of bulk porous glass either by outside vapour deposition [OVD], or by outside vapour phase oxidation [OVPO] or by vapour axial deposition [VAD]
- C03B37/01466—Means for changing or stabilising the diameter or form of tubes or rods
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Glass Melting And Manufacturing (AREA)
- Manufacture, Treatment Of Glass Fibers (AREA)
Abstract
Description
【発明の詳細な説明】
[産業上の利用分野]
本発明は、高純度石英ガラスの製造方法に関するもので
ある。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing high-purity quartz glass.
[従来の技術]
従来より、合成石英カラスを製造する方法の一つとして
、気相反応により多孔質石英ガラスifi材を形成し、
この母材を加熱してガラス化する方法が採用されている
。たとえば光フアイバー用素材としての合成石英ガラス
の製造に関してはVAD法といわれる方法が採用されて
いる。[Prior Art] Conventionally, as one method for producing synthetic quartz glass, a porous quartz glass ifi material is formed by a gas phase reaction,
The method used is to heat this base material and vitrify it. For example, a method called the VAD method is used to manufacture synthetic quartz glass as a material for optical fibers.
この方法は、バーナから珪素化合物、水素。This method uses silicon compounds and hydrogen from the burner.
酸素などの原料ガスを鉛直に懸下した種棒に向けて供給
し、四塩化珪素等の珪素化合物を酸水素炎中で加水分解
させ生成したシリカ微粒子を石英製等の種棒の下端部に
付着・堆積させて多孔質石英ガラスtl材(以下、多孔
質母材または母材と占〈ことがある。)を形成させたの
ち。A raw material gas such as oxygen is supplied to a vertically suspended seed rod, and silica fine particles generated by hydrolyzing silicon compounds such as silicon tetrachloride in an oxyhydrogen flame are placed at the lower end of a seed rod made of quartz or the like. After adhesion and deposition to form a porous silica glass TL material (hereinafter sometimes referred to as porous base material or base material).
上部に設けられたヒータを用いて透明ガラス化する方法
である。この方法では多孔質IfJ材の形成と透明カラ
ス化を連続的に行なうことができる利点がある。この方
法により形成された多孔質母材は、はぼ円柱状の形状を
呈する。This method uses a heater installed at the top to create transparent glass. This method has the advantage that the formation of a porous IfJ material and the formation of transparent glass can be performed continuously. The porous base material formed by this method has a roughly cylindrical shape.
[発明の解決しようとする問題点]
この方法により、フォトマスク基板用等の大型の石英ガ
ラスを製造しようとする場合、多孔質石英ガラス母材を
大型にする必要があり大型の八−すを用いるが、バーナ
から出る火炎は中心部は高温であるがその外周部は中心
部より温度が低い状態となり、かかる温度の違いにより
形成される多孔質石英ガラス母材の外周部の密度はその
中心部より低くなる傾向にある0例えば上記方法により
径30cmの円柱状の多孔質石英ガラス母材を製造した
場合、中心部より低い温度でシリカ微粒子が付着する外
周部の密度は0.1〜0.15g/ccで中心部は0.
35〜0.453/ccとなる。かかる密度分布を持っ
た上記円柱状の多孔質母材を1400〜1500℃に加
熱して透引ガラス化しようとすると、焼成途中で母材外
周部からクラックが発生し破損したり、また透明ロフト
中に欠点か多値に発生する問題が見出された。[Problems to be Solved by the Invention] When attempting to manufacture large-sized quartz glass for photomask substrates, etc. using this method, it is necessary to make the porous quartz glass base material large, and a large eight-piece However, the flame emitted from the burner has a high temperature at the center, but a lower temperature at the outer periphery than the center, and the density at the outer periphery of the porous quartz glass matrix formed by this temperature difference is lower than that at the center. For example, when a cylindrical porous quartz glass base material with a diameter of 30 cm is produced by the above method, the density of the outer periphery, where silica fine particles adhere at a lower temperature than the center, is 0.1 to 0. .15g/cc and 0.15g/cc in the center.
35 to 0.453/cc. When the above-mentioned cylindrical porous base material having such a density distribution is heated to 1400 to 1500°C and attempted to be made into transparent glass, cracks occur from the outer periphery of the base material during firing and damage occurs, and the transparent loft A defect or a problem occurring in multiple values was found.
かかる欠点発生の一つの原因としては、多孔質石英ガラ
ス母材を焼結して透明ガラス化する際、母材は径方向、
軸方向に50〜80%の収縮を伴うが、上記密度分布を
持った母材では中心部と外周部の収縮が不均一に進むた
め径が30cmもの大型母材を一段でガラス化しようと
すると急激な熱収縮に耐えられなくなり、外周部からク
ラックが発生するものと思われる。さらに、大口径母材
では焼成時に中心部と外周部の温度差が大きくなり、一
段で透明ガラス化しようとすると低密度でかつ高温にさ
らされる外周部の焼結がはやく進行し、母材中に含まれ
る気泡が外周部に抜けに〈〈なり、ロフト中に気泡等の
欠点が発生する原因になるものと思われる。One of the causes of such defects is that when a porous quartz glass base material is sintered to become transparent glass, the base material is
Although shrinkage of 50 to 80% occurs in the axial direction, in a base material with the above density distribution, the shrinkage progresses unevenly between the center and the outer periphery, so if you try to vitrify a large base material with a diameter of 30 cm in one step, It is thought that it will not be able to withstand rapid thermal contraction and cracks will occur from the outer periphery. Furthermore, with large-diameter base materials, the temperature difference between the center and the outer periphery becomes large during firing, and if you try to make the glass transparent in one step, the sintering of the outer periphery, which has a low density and is exposed to high temperatures, will progress quickly, causing the inside of the base material to sinter. It is thought that the air bubbles contained in the loft become loose at the outer periphery, causing defects such as air bubbles to occur in the loft.
上記したような多孔質石英ガラス母材の径方向の密度分
布を一定にして母材の収縮を均一化し、欠点の発生を防
ぐことも考えられるが、火炎の温度分布を均一にするこ
とが困難であり、径方向の密度分布の一定した大口径な
多孔質石英カラス母材を得ることははなはだ困難であっ
た。It is possible to make the radial density distribution of the porous quartz glass base material constant as described above to equalize the shrinkage of the base material and prevent the occurrence of defects, but it is difficult to make the temperature distribution of the flame uniform. Therefore, it was extremely difficult to obtain a large-diameter porous quartz glass base material with a constant radial density distribution.
[問題点を解決するための手段]
本発明は、」−記従来技術の問題点を解決し、大口径の
多孔質石英ガラス母材を破損させることなく透明ガラス
化し、得られた石英ガラス中に気泡等の欠点が含まれな
いようにした多孔質石英ガラス母材のガラス化方法を提
供することを目的として研究の結果発明されたものであ
り、その来旨は、右英ガラス製造用神林の一端に堆積・
成長させた多孔質石英ガラス母材を透明ガラス化するに
際して、予め多孔質石英カラスLI材を1150〜13
50℃で仮焼(予備焼成ともいう)して該母材の径方向
の密度分布を整えた後、 1400〜1450℃で焼成
して透明ガラス化することを特徴とする高純度石英ガラ
スの製造方法に関するものである。[Means for Solving the Problems] The present invention solves the problems of the prior art described in ``-'', converts a large-diameter porous quartz glass base material into transparent glass without damaging it, and transforms the resulting quartz glass into transparent glass. It was invented as a result of research with the aim of providing a vitrification method for porous quartz glass base material that does not contain defects such as air bubbles. Deposits at one end of the
When converting the grown porous quartz glass base material into transparent vitrification, the porous quartz glass LI material is preliminarily heated to 1150 to 13
Production of high-purity quartz glass characterized by calcination (also referred to as pre-firing) at 50°C to adjust the density distribution in the radial direction of the base material, and then firing at 1400 to 1450°C to form transparent glass. It is about the method.
本発明において、多孔質母材は、例えば第1図に示した
ような装置によって製造される。すなわち、ポンベ1お
よびポンベ2から水素およヒ酸素がマスフローコントロ
ーラー3.4を通して多重管バーナ5に供給される。ま
た四塩化珪素、トリクロロシラン、四臭化珪素等の珪素
化合物のガスが、タンク6からポンプ7により熱交換器
8を通して多重管バーナ5に供給される。多重管へ−す
5は反応室9内において酸水素炎を形成し、珪素化合物
を加水分解してシリカ微粒子を形成する。なお、図示し
ていないが、窒素、アルゴン等の不活性ガスも八−す5
に供給され、これら珪素化合物のキャリアガスとしであ
るいは酸水素炎中のエアーカーテンとして使用される。In the present invention, the porous base material is manufactured by, for example, an apparatus as shown in FIG. That is, hydrogen and oxygen are supplied from the pumps 1 and 2 to the multi-tube burner 5 through the mass flow controller 3.4. Further, gases of silicon compounds such as silicon tetrachloride, trichlorosilane, and silicon tetrabromide are supplied from the tank 6 to the multi-tube burner 5 by a pump 7 through a heat exchanger 8. The multi-tube chamber 5 forms an oxyhydrogen flame in the reaction chamber 9 to hydrolyze the silicon compound to form silica fine particles. Although not shown in the figure, inert gases such as nitrogen and argon can also be used.
It is used as a carrier gas for these silicon compounds or as an air curtain in an oxyhydrogen flame.
この加水分解反応を珪素化合物が四塩化珪素である場合
について化学式を、示すと次式の用になる。The chemical formula for this hydrolysis reaction when the silicon compound is silicon tetrachloride is as follows.
2 H2+ oz→2H20・・・・・・・・・(1)
2 H2O’+ 5iGla → SiOノ
+ 4)101 ・・・ ・・・ ・・・ (2)
このシリカ微粒子が反応室9で鉛直に懸下された石英製
種棒10の下端部に付着−堆積して順次成侵し、大口径
の多孔質石英ガラス母材11が形成される。なお、反応
によって発生するMCIはNaOH液と洗浄塔13で向
流に接触して吸収除去される。2 H2+ oz→2H20・・・・・・・・・(1)
2 H2O'+ 5iGla → SiOノ
+ 4) 101 ・・・ ・・・ ・・・ (2)
The silica fine particles adhere to and deposit on the lower end of the quartz seed rod 10 suspended vertically in the reaction chamber 9, and are sequentially eroded to form a large-diameter porous quartz glass base material 11. Note that MCI generated by the reaction is brought into contact with the NaOH solution in a countercurrent flow in the washing tower 13 and is absorbed and removed.
本発明においては、上記した方法により製造される多孔
質石英ガラス母材が、1400〜1500℃の温度範囲
における焼成により透明ガラス化する前に、予め115
0〜1350℃の温度範囲にて仮焼して多孔質石英ガラ
ス母材の径方向の密度分布を整える。この仮゛焼はクリ
ーンな雰囲気で行なうことが好ましく、必要に応じて予
めフィルター等で処理された空気、窒素あるいはその他
の不活性ガスを導入しながら加熱炉内で上記温度範囲内
で行なう、仮焼の時間は温度、後述する炉内均温域の長
さ等によって異なるが、仮焼後の多孔質石英ガラス母材
の径方向の収縮率が10〜45z、好ましくは25〜3
5zの範囲になる条件から選ぶことが出来る。収縮率が
loz未満では多孔質石英ガラス母材の外周部密度がま
だ十分高まらず透明ガラス化時に不均質な収縮がおこり
母材がこわれたり、母材外周部に欠点が発生する原因に
なる。また収lii率が45%を超えると、今度は多孔
質石英ガラス母材の外周部の密度が高くなりすぎて、内
部の脱泡が不完全になり透明ガラス中に気泡等の欠点が
発生する原因となる。上記理由により多孔質石英ガラス
母材の仮焼時の収縮率は10〜45駕、好ましくは35
〜402の範囲内で制御する必要がある。In the present invention, the porous quartz glass base material manufactured by the above-described method is preliminarily heated to
The porous quartz glass base material is calcined in a temperature range of 0 to 1350°C to adjust the density distribution in the radial direction. It is preferable to carry out this calcining in a clean atmosphere, and if necessary, air pre-treated with a filter, nitrogen, or other inert gas may be introduced in a heating furnace within the above temperature range. The firing time varies depending on the temperature, the length of the furnace temperature zone described later, etc., but the radial shrinkage rate of the porous quartz glass base material after calcination is 10 to 45z, preferably 25 to 3
You can choose from conditions within the range of 5z. If the shrinkage rate is less than 1 oz, the density of the outer periphery of the porous quartz glass base material will not be sufficiently increased and non-uniform shrinkage will occur during transparent vitrification, resulting in breakage of the base material or defects on the outer periphery of the base material. Furthermore, when the yield exceeds 45%, the density at the outer periphery of the porous quartz glass base material becomes too high, and the internal degassing becomes incomplete, causing defects such as bubbles in the transparent glass. Cause. For the above reasons, the shrinkage rate of the porous quartz glass base material during calcination is 10 to 45, preferably 35.
It is necessary to control within the range of ~402.
本発明において、上記した母材の仮焼は、例えば後記す
る実施例の如く、母材が破損しない程度の比較的低い温
度に昇温した加熱炉(図示せず)内に母材を回転させな
がら挿入し、その後徐々に1150〜1350℃の温度
範囲の温度まで昇温し、該母材を回転させながら該温度
に所要の時間保持する方法で行なうことができる。また
、例えば炉内の下部から上部に向けて高まる温度勾配を
設けた加熱炉あるいは前記温度勾配をもっと共に加熱炉
内上部の部分領域が上下方向に温度がほぼ均等な均温域
になるような温度分布を設けた加熱炉において、前記し
た方法により製造した母材を先ず前記仮焼を行なう加熱
炉(図示せず)の下部に挿入し種棒を回転させながら該
加熱炉の上部に移動させつつ母材の上部より徐々に仮焼
を行なったのち前記加熱炉の上部から仮焼ずみ母材を抜
き出す方法で行なうこともできる。In the present invention, the above-mentioned calcination of the base material is carried out by rotating the base material in a heating furnace (not shown) heated to a relatively low temperature such that the base material is not damaged, for example, as in the embodiment described later. This can be carried out by inserting the base material while the base material is being rotated, then gradually raising the temperature to a temperature in the range of 1150 to 1350°C, and maintaining the base material at this temperature for the required time while rotating the base material. In addition, for example, a heating furnace is provided with a temperature gradient that increases from the bottom to the top of the furnace, or the temperature gradient is further increased so that a partial area in the upper part of the heating furnace becomes a uniform temperature region where the temperature is almost uniform in the vertical direction. In a heating furnace provided with a temperature distribution, the base material produced by the method described above is first inserted into the lower part of the heating furnace (not shown) in which the calcination is performed, and the seed rod is moved to the upper part of the heating furnace while rotating. Alternatively, the calcining may be carried out gradually from the upper part of the base material, and then the calcined base material is extracted from the upper part of the heating furnace.
かかる仮焼を行なったのち、多孔質石英ガラス母材は仮
焼を行なった炉において又は別の加熱炉に移して、直ち
に又は所定時間をおいて本焼結させ透明ガラス化させる
。この本焼結は、Heガスを少なくとも70%以上好ま
しくは80〜902を含む雰囲気の加熱炉において14
00〜1500℃の温度域において行なう0本焼結の時
間は、温度やHee度によっても異なるが1.5〜4時
間が適当である。After performing such calcination, the porous quartz glass base material is transferred to the furnace in which the calcination was performed or to another heating furnace, and is sintered immediately or after a predetermined period of time to become transparent vitrification. This main sintering is carried out in a heating furnace in an atmosphere containing He gas of at least 70% or more, preferably 80 to 902.
The time for zero-strand sintering performed in the temperature range of 00 to 1500°C varies depending on the temperature and degree of Hee, but is suitably 1.5 to 4 hours.
本発明1において、多孔質石英ガラス母材を透明ガラス
化(以下、上記の本焼結と透明ガラス化を単に透明ガラ
ス化と書く)する加熱炉は、」二部から1部に向けて高
まる温度勾配が設けられるよ)にするのが好ましい、こ
のようにすれば、多孔質石英ガラス母材を加熱炉の上方
から該炉内に挿入するに際して母材の温度を徐々に高め
ていくことができ、また急激な温度変化により透明ガラ
ス中に気泡が残留するのを防止することができる。この
際の温度勾配は、多孔質石英ガラス母材のガラス化温度
が1400℃以上であることから、加熱炉の上部を、1
200℃前後、炉の下部の温度を1400〜1500℃
とするのが適当であり、透明ガラス化に際して種棒の下
端部近傍が1400℃以上の高温域に達した時点で下降
を停止するのが最適である。このようにすれば、母材を
種棒に支持した状態で多孔質石英ガラス母材を完全に透
明ガラス化することができる。In the present invention 1, the heating furnace for converting the porous quartz glass base material into transparent vitrification (hereinafter, the above-mentioned main sintering and transparent vitrification will simply be referred to as transparent vitrification) increases from 2 parts to 1 part. It is preferable to create a temperature gradient. In this way, the temperature of the porous quartz glass base material can be gradually increased when the porous quartz glass base material is inserted into the furnace from above. It is also possible to prevent air bubbles from remaining in the transparent glass due to sudden temperature changes. The temperature gradient at this time is such that the upper part of the heating furnace is
Around 200℃, lower temperature of furnace 1400-1500℃
During transparent vitrification, it is optimal to stop the descent when the vicinity of the lower end of the seed rod reaches a high temperature range of 1400° C. or higher. In this way, the porous quartz glass base material can be completely transformed into transparent glass while the base material is supported by the seed rod.
このようにすれば、石英製種棒が軟化する1400℃以
−Lの高温域に種棒を長時間さらすことなく母材の透明
ガラス化が回部であり、これにより種棒が軟化して燕麦
するのを防止し、大口径石英ガラスロッドを落下するこ
となく支持出来る。さらに透明ガラス化に伴なって流出
する気泡は、まだ透明ガラス化されていない上部の多孔
質層に逃げることができるので、得られた石英ガラス中
に気泡が含有するのを防止することができる。In this way, the base material can be turned into transparent vitrification without exposing the seed rod for a long time to the high temperature range of 1400°C or higher, which softens the quartz seed rod, which softens the seed rod. It prevents oats from falling and can support large diameter quartz glass rods without falling. Furthermore, air bubbles that flow out due to transparent vitrification can escape to the upper porous layer that has not yet been transparent vitrified, so it is possible to prevent air bubbles from being contained in the obtained quartz glass. .
本発明において、仮焼及び透明ガラス化時の加熱は多孔
質石英ガラス母材を回転させながら加熱炉内に徐々に挿
入しておこなう0回転することにより、母材を均一に加
熱することができ、焼成時に不均一な収縮がおこり母材
が変形するのを防止することができる。In the present invention, the heating during calcination and transparent vitrification is performed by gradually inserting the porous quartz glass base material into the heating furnace while rotating it, and by rotating the porous quartz glass base material at zero rotation, the base material can be heated uniformly. , it is possible to prevent the base material from deforming due to non-uniform shrinkage during firing.
また、本発明において母材を透明ガラス化する加熱炉は
上記の如く該加熱炉内の上部から下部に向けて高まる温
度勾配が設けられているが、前記温度勾配をもつと共に
加熱炉内下部の部分領域が上下方向に温度がほぼ均等な
均温域になるような温度分布をもっていてもよい。Further, in the present invention, the heating furnace for converting the base material into transparent vitrification is provided with a temperature gradient that increases from the top to the bottom in the heating furnace as described above. The partial region may have a temperature distribution such that the temperature is approximately equal in the vertical direction and becomes a uniform temperature region.
実施例
第1図に示した装置を利用して製造された石英製の種棒
に形成された円柱状の多孔質石英ガラス母材(直径30
c層、長さ0.5m、中心部(中心から径3cmの部分
)の平均密度は0.45g/cc 、表面部(表層部か
ら4cmの部分)の平均密度は0.23/cc )をゆ
っくり回転させながら300℃に保持された加熱炉(図
示せず)内に挿入し、炉下端よりN2ガスを3m3/H
rで供給しながら250℃/Hrの昇温速度で1300
℃まで熱上げし、この条件下で60分間保持した。これ
が母材の仮焼である。この仮焼後の多孔質石英ガラス母
材の径方向の収縮率は約35%であり、中心部の平均密
度が0.6g7ccで外周部の平均密度は0.68g/
ccであった。仮焼を行なった後、直ちに第2図に示す
ように1石英製の種棒10の付いた仮焼した多孔質石英
ガラス母材11を、径が35c鵬の環状ヒータ22が設
けられ、85%濃度のヘリウム雰囲気に保たれている加
熱炉21内に上方から挿入した。この加熱炉21は、上
部が約1200℃、下部が約1430℃の温度勾配を有
し、1400℃以上の均温域が約20c纏になるように
制御されている0種棒lOをゆっくり回転させながら1
00曽鶴/Hrの速度で下降させ、多孔質石英ガラス母
材11をその下端部からヒータ22内に挿入した(第2
図(a))。Example A cylindrical porous quartz glass base material (diameter 30 mm) was formed on a quartz seed rod manufactured using the apparatus shown in FIG.
C layer, length 0.5 m, average density in the center (3 cm in diameter from the center) is 0.45 g/cc, and average density in the surface (4 cm from the surface) is 0.23/cc). It is inserted into a heating furnace (not shown) maintained at 300℃ while rotating slowly, and N2 gas is supplied at 3m3/H from the bottom of the furnace.
1300 at a heating rate of 250°C/Hr while supplying at r.
The temperature was raised to 0.degree. C. and held under these conditions for 60 minutes. This is the calcination of the base material. The shrinkage rate in the radial direction of the porous quartz glass base material after calcination is approximately 35%, and the average density at the center is 0.6 g/7 cc, and the average density at the outer periphery is 0.68 g/7 cc.
It was cc. Immediately after calcining, as shown in FIG. The sample was inserted from above into a heating furnace 21 maintained in a helium atmosphere with a helium concentration of 1.5%. This heating furnace 21 has a temperature gradient of about 1200°C in the upper part and about 1430°C in the lower part, and slowly rotates a class 0 rod IO which is controlled so that the uniform temperature range above 1400°C is about 20cm. while letting 1
The porous quartz glass base material 11 was inserted into the heater 22 from its lower end by descending at a speed of 00 Sokaku/Hr (second
Figure (a)).
この多孔質石英ガラス母材11は、下端部から徐々に脱
泡されて透明ガラス化し、径が約13c層の透明ガラス
23となった(第2図(b))、このようにして透明ガ
ラス化した石英ガラスは、その表面層(約51履厚み)
から内側の中心部には欠点の発生はなく、又、この表面
に発生した気泡も表面積1 cm2当り平均0.8個と
少なかった。This porous quartz glass base material 11 was gradually degassed from the lower end and turned into transparent glass, forming transparent glass 23 with a diameter of approximately 13 cm (FIG. 2(b)). The surface layer of the fused silica glass (approx. 51 mm thick)
There were no defects in the inner center, and the number of bubbles generated on this surface was as small as 0.8 on average per 1 cm2 of surface area.
一方、仮焼を行なわずに同上の方法により透明ガラス化
を行なったところ母材が下端部から約%程透明ガラス化
した時点で、上部多孔質ガラス部にクラックが発生し、
この部分から下が落下した。この透明ガラス化した部分
について内部欠点を評価した結果、その表面層(約3c
+s厚み)から内側の中心部には欠点の発生はなかった
ものの、この表面層にはICl3当り平均20個もの多
量の欠点が発生していた。On the other hand, when transparent vitrification was performed by the same method as above without performing calcination, cracks occurred in the upper porous glass part when the base material had become transparent vitrification by about % from the lower end.
The bottom fell off from this part. As a result of evaluating the internal defects of this transparent vitrified part, we found that the surface layer (approximately 3 cm
Although no defects were found in the inner central part from +s thickness), an average of 20 defects were found in this surface layer per 3 ICl.
また、前述した方法による仮焼時の保持時間を約180
分と長くし、多孔質石英ガラス母材の径方向の収縮率を
5Hまで高めたものについて上記方法により透明ガラス
化した結果、母材にクラックが入ることなく透明ガラス
化が可能であった。しかし、この石英ガラスの表面層(
約5層■厚み)には欠点が1c■2当り0.8個程度と
少なかったものの、表面層から内側の部分にも石英ガラ
ス1kg当り0.6〜1個程度の欠点が認められた。In addition, the holding time during calcination using the method described above is approximately 180%.
When the radial shrinkage rate of the porous quartz glass base material was increased to 5H and the shrinkage rate in the radial direction of the porous quartz glass base material was increased to 5H, transparent vitrification was performed using the above method, and as a result, transparent vitrification was possible without cracking the base material. However, the surface layer of this quartz glass (
Although the number of defects was as low as 0.8 defects per 1 c 2 (approximately 5 layers thick), about 0.6 to 1 defect per 1 kg of quartz glass was also observed in the inner part from the surface layer.
[発明の効果]
以上説明したように、本発明によれば多孔質石英ガラス
母材を焼結によって透明ガラス化処理する前に、予め透
明ガラス化処理の温度より低い温度で仮焼して多孔質石
英ガラス母材の径方向の密度分布の均一化をはかってい
るので、急激な収縮によりクラックが発生するのを防止
出来る。また、多孔質石英ガラス母材の径方向の密度分
布の差に起因する気泡等内部欠点の発生を著しく低下す
ることができ、品質の向上、歩留りの向上が得られる。[Effects of the Invention] As explained above, according to the present invention, before a porous quartz glass base material is subjected to a transparent vitrification treatment by sintering, it is calcined in advance at a temperature lower than the temperature of the transparent vitrification treatment to form a porous quartz glass base material. Since the quartz glass base material has a uniform density distribution in the radial direction, it is possible to prevent cracks from occurring due to rapid shrinkage. Furthermore, the occurrence of internal defects such as bubbles due to differences in the radial density distribution of the porous quartz glass base material can be significantly reduced, resulting in improved quality and yield.
特に、大口径の多孔質石英ガラス母材の透明ガラス化に
本発明の方法は最適であり、上記の効果が顕著であって
、高純度石英ガラスを得ることができる。In particular, the method of the present invention is most suitable for transparent vitrification of a large-diameter porous quartz glass base material, the above-mentioned effects are remarkable, and high-purity quartz glass can be obtained.
第1図は多孔質石英ガラス母材を得るための装置の一例
を示す説明図、第2図(a)、(b)は本発明によるガ
ラス化方法の実施例を示す説明図である。FIG. 1 is an explanatory view showing an example of an apparatus for obtaining a porous quartz glass base material, and FIGS. 2(a) and 2(b) are explanatory views showing an example of the vitrification method according to the present invention.
Claims (3)
石英ガラス母材を加熱して透明ガラス化するに際して、
予め多孔質ガラス母材を 1150〜1350℃で仮焼して該母材の径方向の密度
分布を整えた後、1400〜1500℃で焼成して透明
ガラス化することを特徴とする高純度石英ガラスの製造
方法。(1) When heating the porous quartz glass base material deposited and grown on one end of the quartz glass seed rod to turn it into transparent vitrification,
A high-purity quartz characterized by preliminarily calcining a porous glass base material at 1150 to 1350°C to adjust the density distribution in the radial direction of the base material, and then firing at 1400 to 1500°C to form transparent glass. Glass manufacturing method.
いて、10〜45%収縮させることを特徴とする特許請
求の範囲第1項記載の高純度石英ガラスの製造方法。(2) The method for producing high-purity quartz glass according to claim 1, wherein the calcination shrinks the porous quartz glass base material by 10 to 45% in the radial direction.
装置内に徐々に挿入して行い、多孔質石英ガラス母材を
径方向において10〜45%収縮させることを特徴とす
る特許請求の範囲第1項記載の高純度石英ガラスの製造
方法。(3) A patent characterized in that the calcination is performed by gradually inserting the porous base material into a heating device while rotating the porous quartz glass base material, thereby shrinking the porous quartz glass base material by 10 to 45% in the radial direction. A method for producing high-purity quartz glass according to claim 1.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22279985A JPS6283325A (en) | 1985-10-08 | 1985-10-08 | Production of quartz glass having high purity |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP22279985A JPS6283325A (en) | 1985-10-08 | 1985-10-08 | Production of quartz glass having high purity |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS6283325A true JPS6283325A (en) | 1987-04-16 |
JPH0478567B2 JPH0478567B2 (en) | 1992-12-11 |
Family
ID=16788077
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP22279985A Granted JPS6283325A (en) | 1985-10-08 | 1985-10-08 | Production of quartz glass having high purity |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6283325A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01145344A (en) * | 1987-12-02 | 1989-06-07 | Fujikura Ltd | Production of glass article |
JPH0264028A (en) * | 1988-08-30 | 1990-03-05 | Shin Etsu Chem Co Ltd | Synthetic silica glass for resisting ultraviolet light and production thereof |
JPH04321530A (en) * | 1990-12-21 | 1992-11-11 | Alcatel Nv | Method of preparing optical waveguide preform |
EP0626351A1 (en) * | 1993-05-24 | 1994-11-30 | Litespec, Inc. | Process for sintering porous optical fibre preforms |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59174538A (en) * | 1983-03-24 | 1984-10-03 | Hitachi Cable Ltd | Manufacture of base material for optical fiber |
JPS60186427A (en) * | 1984-03-01 | 1985-09-21 | Nippon Telegr & Teleph Corp <Ntt> | Manufacture of optical fiber preform |
JPS61281036A (en) * | 1985-06-03 | 1986-12-11 | Nippon Telegr & Teleph Corp <Ntt> | Production of preform for optical fiber |
JPS6230636A (en) * | 1985-07-30 | 1987-02-09 | Furukawa Electric Co Ltd:The | Vitrification of optical fiber preform |
-
1985
- 1985-10-08 JP JP22279985A patent/JPS6283325A/en active Granted
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59174538A (en) * | 1983-03-24 | 1984-10-03 | Hitachi Cable Ltd | Manufacture of base material for optical fiber |
JPS60186427A (en) * | 1984-03-01 | 1985-09-21 | Nippon Telegr & Teleph Corp <Ntt> | Manufacture of optical fiber preform |
JPS61281036A (en) * | 1985-06-03 | 1986-12-11 | Nippon Telegr & Teleph Corp <Ntt> | Production of preform for optical fiber |
JPS6230636A (en) * | 1985-07-30 | 1987-02-09 | Furukawa Electric Co Ltd:The | Vitrification of optical fiber preform |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01145344A (en) * | 1987-12-02 | 1989-06-07 | Fujikura Ltd | Production of glass article |
JP2561103B2 (en) * | 1987-12-02 | 1996-12-04 | 株式会社フジクラ | Method for manufacturing glass article |
JPH0264028A (en) * | 1988-08-30 | 1990-03-05 | Shin Etsu Chem Co Ltd | Synthetic silica glass for resisting ultraviolet light and production thereof |
JPH0733259B2 (en) * | 1988-08-30 | 1995-04-12 | 信越化学工業株式会社 | Ultraviolet-resistant synthetic quartz glass and method for producing the same |
JPH04321530A (en) * | 1990-12-21 | 1992-11-11 | Alcatel Nv | Method of preparing optical waveguide preform |
EP0626351A1 (en) * | 1993-05-24 | 1994-11-30 | Litespec, Inc. | Process for sintering porous optical fibre preforms |
Also Published As
Publication number | Publication date |
---|---|
JPH0478567B2 (en) | 1992-12-11 |
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