200533617 (1) 九、發明說明 【發明所屬之技術領域】 本發明係關於將粗徑之光纖母材縮徑延伸成預定的徑 之方法’其特徵在於抑制雜質附著於母材表面，以高度良 品率獲得光纖母材之光纖母材之加工方法及光纖母材。 【先前技術】 Φ 當在光纖母材的表面存在有傷痕或雜質時，則會形成 拉線時之良品率降低的原因。又，當在光纖母材存在有彎 折或徑變動時，則不易安裝於拉線機，或無法獲得均等徑 之光纖。 作爲光纖母材，被要求表面平滑且不存在有彎折及雜 質者。因此，一般係使用玻璃車床，藉由以鎖狀碳氫氣體 或氫氣作爲燃燒氣體之燃燒器火焰，在彎折修正、延伸、 火焰硏磨之一連串的製程，來進行光纖母材之加工。 Φ 光纖母材係在配合拉線機，縮徑成預定的徑後，熔著 虛擬玻璃棒，進行了火焰硏磨後，裝設至拉線機加以加熱 、熔融，而拉引成光纖狀。此時，由於光纖母材之尺寸精 度會影響進行拉線所獲得之光纖的尺寸精度，故在延伸中 ，於頸縮（neck down )部與其附近之2點測定外徑，根 據此，來調節控制延伸速度，藉此獲得尺寸精度高之光纖 的方法爲眾所皆知（參照專利文獻1 )。 一般，光纖母材之加工係在無塵室或以該無塵室爲標 準之環境中進行，且在極力地使雜質不附著於光纖母材之 -4- 200533617 (2) 環境中進行。但，在最終製程之火焰硏磨製程結束後，或 在火焰硏磨中’會有在表面發現雜質之情事。此時，進行 將雜質附著部熔斷去除之作業，造成良品率大幅度地降低 。又’亦會有受到因附著位置造成變短，必須廢棄該母材 全體之情事。 因此’被期待有在光纖母材之表面不會附著雜質之光 纖母材的加工方法。 【專利文獻1】日本特開昭5 6 - 9 2 3 1號公報 【發明內容】 〔發明所欲解決之課題〕 本發明之目的係在於提供一種雜質不會附著於光纖母 材的表面之光纖母材之加工方法及光纖母材。 〔用以解決課題之手段〕 本發明之光纖母材之加工方法，係針對將兩端藉由握 持構件例如夾具所支承之母材一邊旋轉，一邊以加熱器火 焰加熱來進行加工之方法，其特徵爲：在將該光纖母材縮 徑成預定的徑之延伸製程之前，進行火焰硏磨製程。 在進行火焰硏磨製程後連續進行延伸製程爲佳，又， 亦可在進行了延伸製程後進一步連續進行火焰硏磨製程。 火焰硏磨製程之光纖母材的表面溫度爲1 8 00 °C以上且未 滿2200 °C，而延伸製程之光纖母材的表面溫度爲2000 °C 以上且未滿2 5 0 0 °C。在火焰硏磨製程，將光纖母材全體 200533617 (3) 進行火焰硏磨。而燃燒器火焰係以氫氣及/或鎖狀 體作爲燃燒氣體之燃燒火焰。 本發明之光纖母材係使用上述光纖母材之加工 進行了火焰硏.磨加工及延伸加工者。 〔發明效果〕 本發明的光纖母材之加工方法，藉由連續進行 磨製程與延伸製程，可抑制雜質附著至光纖母材之 以商良品率來獲得光纖母材。 【實施方式】 本發明者們，反復精心硏究之結果，發現藉由 纖母材，連續進行火焰硏磨製程與延伸製程，以代 的方法，能在光纖母材之加工中，抑制雜質附著至 面，而開發完成出本發明。 本發明之光纖母材之加工方法，係如圖1所示 行。 光纖母材1，其兩端藉由夾持構件也就是固定 及可動夾具3來支承，藉由馬達4來旋轉。火焰硏 由燃燒器5將光纖母材加熱至180(rc以上、未滿 之溫度，沿著光纖母材1使其移動來進行的。 在火焰硏磨結束後，進一步以燃燒器5加熱三 °C以上、未滿25 00 °C之溫度，藉由配合母材之軟 牽引可動夾具3 ’來將光纖母材丨延伸成預定的徑 碳氫氣 方法， 火焰硏 表面， 對於光 替以往 母材表 般來進 夾具2 磨係藉 2 2 0 0 °C i 20 0 0 化度以 。再者 -6- 200533617 (4) ，在圖中，省略了燃燒器5之移動手段、可動夾具3之牽 引手段及調整控制手段、外徑測定手段等。 圖1所示的例子係將光纖母材呈水平地支承來進行加 工之方法，但亦可將光纖母材呈垂直地支承來進行。 當在光纖母材加工中，檢測附著於母材表面之雜質， 則可得知，鐵、鉻、鎳之金屬材料爲原因者佔其大部分。 這些附著於玻璃母材表面之雜質的大小係有數百微米至數 0 毫米，但實際上，數微米至數十微米等級之金屬粒子附著 ，而擴散於玻璃中，看起來很大。但，要由作業環境中將 這些粒子消滅是極爲困難的。 火焰硏磨由於藉由在較低溫的加熱，來熔融、硏磨數 微米至數十微米之表面層，故被常用作爲一個除去附著於 表面的氧化矽微粒子等之雜質的除去方法。且，由於不僅 除去附著於表面之雜質，亦能除去彎曲，故通常此製程係 被使用於最終之拋光製程。在火焰硏磨後，表面狀態變得 Q 圓滑，形成新的雜質不易附著之狀態。 進行火焰硏磨加工之溫度係在光纖母材之表面溫度 1 8 00 °C以上、未滿2200 °C之溫度，但理想爲1 900 °C以上 、未滿2100 °C。當超過2200 °C之溫度時，則變得不易除 去雜質，並且會進一步朝內部擴散。 接著所進行之延伸加工係由於加熱至較硏磨加工更高 溫後來進行，故以火焰硏磨表面之能力高，但一旦雜質附 著時，則受到火焰施加應力，會造成雜質較硏磨先被埋入 至母材表面，而逐漸地朝內部擴散。 -7- 200533617 (5) 因此，藉由在將光纖母材之表面除去雜質且作成雜質 不易附著之狀態後，接著立刻進行延伸製程’能夠抑制在 母材加工中雜質之附著。 進行延伸加工之溫度係在在光纖母材之表面溫度 2 0 0 0 °C以上、未滿2 5 0 0 °C之溫度下進行的溫度，但理想 爲2200°C以上、未滿2500°C。當在較2000°C低之溫度下 進行時，則軟化會不充分，爲了進行延伸而需要強力的張 力，使得對於機器之負擔變大。 藉由在以上的條件下連續進行火焰硏磨製程與延伸製 程，可抑制在光纖母材加工中，雜質附著至母材表面，能 以高的良品率獲得光纖母材。 以下，根據實施例與比較例具體地說明本發明，但本 發明不限於以下之實施例者。 〔實施例1〕 在具備氫氣火焰加熱器之玻璃車床，安裝平均徑 0 65mm之光纖母材，其中氫氣火焰燃燒器具有供給作爲 助燃氣體之氧氣的氧氣噴嘴，而該光纖母材在兩端接續有 虛擬棒。 首先，以氫氣250 L/min、氧氣150 L/min進行了 火焰硏磨。此時的表面溫度爲2 0 5 0 °C。接著，使表面溫 度形成2200°C地，以氫氣240 L/min、氧氣1〇〇 L/min 進行延伸，使徑形成0 60mm。接著，以氫氣2 5 0 L/ min 、氧氣150 L/min進行火焰硏磨。。針對丨〇〇支進行上 200533617 (6) 述一連串操作，檢查最終完成表面，在100支中， 確認了在表面呈褐色之雜質。產生率爲2%。 〔實施例2〕 將平均徑0 55 mm之光纖母材的兩端連接虛擬 安裝至玻璃車床。 首先，以氫氣270 L/min、氧氣170 L / min 火焰硏磨。此時的表面溫度爲2100 °C。接著，使 度形成2400°C地，以氫氣260 L/min、氧氣150 進行延伸，使徑形成分60mm。接著，以氫氣250 、氧氣150 L/min進行火焰硏磨。。針對100支 述一連串操作，檢查最終完成表面，在100支中， 確認了在表面呈褐色之雜質，產生率爲1%。 (比較例1 ) 除了在進行延伸加工前不進行火焰硏磨以外， 施例1進行1 0 0支之加工，檢查最終完成表面，在 中’有10支確認了在表面呈褐色之雜質，產生率j (比較例2 ) 除了在進行延伸加工前不進行火焰硏磨以外， 施例2進行1 〇 〇支之加工，檢查最終完成表面，在 中’有9支確認了在表面呈褐色之雜質，產生率爲 有2支 棒後， 進行了 表面溫 L/min L/min 進行上 有1支 根據實 100支 I 10% 根據實 100支 9% 。 -9- 200533617 (7) 〔產業上之利用可能性〕 若根據本發明之光纖母材之加工方法的話，可抑制雜 質附著於母材表面，能以高良品率獲得光纖母材，有助於 降低製造成本。 【圖式簡單說明】 ，） 圖1係說明本發明之光纖母材之加工方法的槪略說明 圖。 【主要元件符號說明】 1…光纖母材 2…固定夾具 3…可動夾具 4…馬達 〇 5…燃燒器 -10-200533617 (1) IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to a method for reducing the diameter of a large-diameter optical fiber base material to a predetermined diameter. The processing method of optical fiber base material and optical fiber base material to obtain optical fiber base material. [Prior art] Φ When there are flaws or impurities on the surface of the optical fiber base material, the cause of the decrease in the yield when the cable is drawn will be formed. In addition, when there is a bend or a change in diameter of the optical fiber base material, it is not easy to install it on a wire drawing machine, or an equal diameter optical fiber cannot be obtained. As the optical fiber base material, the surface is required to be smooth and free of bends and impurities. Therefore, a glass lathe is generally used to process the optical fiber base material through a series of processes such as bending correction, extension, and flame honing through a burner flame using lock-shaped hydrocarbon gas or hydrogen as a combustion gas. Φ The optical fiber base material is matched with a wire drawing machine to reduce the diameter to a predetermined diameter, and then a virtual glass rod is fused. After flame honing, it is installed in the wire drawing machine to heat and melt, and is drawn into an optical fiber. At this time, since the dimensional accuracy of the optical fiber base material will affect the dimensional accuracy of the optical fiber obtained by the drawing, during the extension, the outer diameter is measured at the neck down portion and two points near it, and adjusted based on this A method of controlling an extension speed to obtain an optical fiber with high dimensional accuracy is known (see Patent Document 1). Generally, the processing of the optical fiber base material is performed in a clean room or an environment based on the clean room, and in an environment where foreign matter is strongly prevented from adhering to the optical fiber base material -4- 200533617 (2). However, after the flame honing process of the final process is completed, or during the flame honing process, impurities may be found on the surface. At this time, the operation of fusing and removing the impurity adhered portion is performed, and the yield is greatly reduced. In addition, it may be shortened due to the attachment position, and the whole base material must be discarded. Therefore, a processing method of the optical fiber base material which does not adhere to the surface of the optical fiber base material is expected. [Patent Document 1] Japanese Patent Laid-Open No. 5 6-9 2 3 1 [Summary of the Invention] [Problems to be Solved by the Invention] The object of the present invention is to provide an optical fiber in which impurities do not adhere to the surface of the optical fiber base material. Processing method of base material and optical fiber base material. [Means to Solve the Problem] The method for processing an optical fiber base material of the present invention is directed to a method in which the base material supported at both ends by a holding member such as a jig is rotated while heated by a heater flame, It is characterized in that a flame honing process is performed before the optical fiber base material is reduced to a predetermined diameter extension process. The flame honing process is preferably performed continuously after the flame honing process, and the flame honing process may be further continuously performed after the extension process is performed. The surface temperature of the optical fiber base material in the flame honing process is above 1 800 ° C and less than 2200 ° C, and the surface temperature of the optical fiber base material in the extension process is above 2000 ° C and less than 2 500 ° C. In the flame honing process, the entire fiber preform 200533617 (3) is flame honed. The burner flame is a combustion flame using hydrogen and / or locks as the combustion gas. The optical fiber base material of the present invention is a flame honing process and an elongation process using the above-mentioned optical fiber base material. [Inventive Effect] The method for processing an optical fiber preform according to the present invention can continuously obtain the optical fiber preform with a good yield by suppressing the attachment of impurities to the optical preform by continuously performing a grinding process and an extension process. [Embodiment] As a result of repeated careful research, the present inventors found that by continuously performing the flame honing process and the extension process through the fiber base material, the substitution method can suppress the adhesion of impurities in the processing of the optical fiber base material. To this end, the present invention has been developed. The processing method of the optical fiber preform of the present invention is shown in Fig. 1. The optical fiber base material 1 is supported at both ends by a clamping member, that is, a fixed and movable jig 3, and is rotated by a motor 4. After the flame honing, the burner 5 heats the optical fiber base material to a temperature of 180 ° C or higher and moves it along the optical fiber base material 1. After the flame honing is completed, the burner 5 is further heated for three degrees. Above the temperature of C and below 25 00 ° C, the optical fiber base material is extended to a predetermined diameter of carbon and hydrogen by matching the base material with a soft traction movable clamp 3 '. In general, the fixture 2 is milled at 2 2 0 ° C i 2 0 0 degrees. Furthermore, -6- 200533617 (4), in the figure, the moving means of the burner 5 and the traction of the movable fixture 3 are omitted. Means, adjustment control means, outer diameter measuring means, etc. The example shown in Figure 1 is a method of processing the optical fiber base material horizontally, but it can also be performed by supporting the optical fiber base material vertically. In the processing of the base material, if the impurities attached to the surface of the base material are detected, it can be known that the metal materials of iron, chromium and nickel account for the majority. The size of these impurities attached to the surface of the glass base material is hundreds. Micrometers to several millimeters, but in fact, several micrometers Metal particles on the order of tens of micrometers are attached and diffuse into the glass, which seems very large. However, it is extremely difficult to destroy these particles in the operating environment. Flame honing is melted by heating at a lower temperature And honing a surface layer of several micrometers to tens of micrometers, so it is commonly used as a method of removing impurities such as silicon oxide particles attached to the surface. Moreover, not only the impurities on the surface can be removed, but also the curvature can be removed, Usually this process is used in the final polishing process. After flame honing, the surface state becomes Q smooth, and new impurities are not easily attached. The temperature for flame honing processing is the surface temperature of the optical fiber base material 1 Temperatures above 8 00 ° C and below 2200 ° C, but preferably above 1 900 ° C and below 2100 ° C. When the temperature exceeds 2200 ° C, it becomes difficult to remove impurities, and it will further move toward the inside Diffusion. The subsequent elongation process is performed after heating to a higher temperature than the honing process, so the ability to honing the surface by flame is high, but once impurities are attached It will be stressed by the flame, which will cause the impurities to be buried in the surface of the base material before honing, and gradually diffuse into the interior. -7- 200533617 (5) Therefore, by removing the impurities on the surface of the optical fiber base material and making Immediately after the state where impurities are not easily adhered, an extension process is performed to suppress the adhesion of impurities in the processing of the base material. The temperature of the extension processing is above the surface temperature of the optical fiber base material above 2 0 0 ° C and less than 2 5 A temperature of 0 0 ° C, but it is preferably 2200 ° C or higher and less than 2500 ° C. When it is performed at a temperature lower than 2000 ° C, softening is insufficient, and strong force is required for stretching. The tension makes the burden on the machine larger. By continuously performing the flame honing process and the extension process under the above conditions, it is possible to suppress impurities from adhering to the surface of the base material during the processing of the optical fiber base material, and to obtain the optical fiber base material with a high yield. Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples. [Example 1] On a glass lathe equipped with a hydrogen flame heater, an optical fiber base material having an average diameter of 0 65 mm was installed. The hydrogen flame burner had an oxygen nozzle for supplying oxygen as a combustion-supporting gas, and the optical fiber base material was connected at both ends. There are virtual sticks. First, flame honing was performed with 250 L / min of hydrogen and 150 L / min of oxygen. The surface temperature at this time was 2 50 ° C. Next, the surface temperature was set to 2200 ° C, and the film was stretched at 240 L / min of hydrogen and 100 L / min of oxygen to have a diameter of 0 to 60 mm. Next, flame honing was performed at 250 L / min of hydrogen and 150 L / min of oxygen. . A series of operations described in 200533617 (6) were performed on 丨 〇〇 sticks, and the final surface was checked. Among 100 sticks, brown impurities on the surface were confirmed. The rate is 2%. [Example 2] Both ends of an optical fiber base material having an average diameter of 0 55 mm were connected to a glass lathe and virtually attached. First, honing with a flame of hydrogen 270 L / min and oxygen 170 L / min. The surface temperature at this time was 2100 ° C. Next, the sheet was formed at a temperature of 2400 ° C, and was stretched at 260 L / min of hydrogen and 150 of oxygen to form a diameter of 60 mm. Next, flame honing was performed at 250 L of hydrogen and 150 L / min of oxygen. . A series of operations were performed for 100 sticks, and the final surface was checked. Among the 100 sticks, brown impurities on the surface were confirmed, and the generation rate was 1%. (Comparative Example 1) Except that no flame honing was performed before the extension processing, Example 1 was processed with 100 pieces, and the surface was finally inspected. Among the 10 pieces, 10 pieces were confirmed to have brown impurities on the surface and generated. Rate j (Comparative Example 2) Except that no flame honing was performed before the extension processing, Example 2 was processed for 100 pieces, and the surface was finally inspected. Among them, 9 pieces were confirmed to have brown impurities on the surface. After the production rate is 2 sticks, the surface temperature L / min L / min is carried out, and there is 1 stick based on the actual 100 sticks and 10% based on the real 100 sticks and 9%. -9- 200533617 (7) [Industrial application possibility] If the optical fiber preform processing method according to the present invention is used, impurities can be prevented from adhering to the surface of the preform, and the optical fiber preform can be obtained with a high yield, which is helpful. Reduce manufacturing costs. [Brief description of the drawings] FIG. 1 is a schematic diagram illustrating a processing method of the optical fiber preform of the present invention. [Description of main component symbols] 1 ... fiber optic base material 2 ... fixture fixture 3 ... movable fixture 4 ... motor 〇5 ... burner -10-