KR20030095850A - method of prevention of water generation in the jacketing tube during RIT and apparatus thereof - Google Patents
method of prevention of water generation in the jacketing tube during RIT and apparatus thereof Download PDFInfo
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- KR20030095850A KR20030095850A KR1020020033449A KR20020033449A KR20030095850A KR 20030095850 A KR20030095850 A KR 20030095850A KR 1020020033449 A KR1020020033449 A KR 1020020033449A KR 20020033449 A KR20020033449 A KR 20020033449A KR 20030095850 A KR20030095850 A KR 20030095850A
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- G—PHYSICS
- G02—OPTICS
- G02C—SPECTACLES; SUNGLASSES OR GOGGLES INSOFAR AS THEY HAVE THE SAME FEATURES AS SPECTACLES; CONTACT LENSES
- G02C5/00—Constructions of non-optical parts
- G02C5/12—Nose pads; Nose-engaging surfaces of bridges or rims
- G02C5/126—Nose pads; Nose-engaging surfaces of bridges or rims exchangeable or otherwise fitted to the shape of the nose
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Abstract
Description
본 발명은 RIT 공정에서의 경계지점 수분발생 방지 방법에 관한 것으로서, 더욱 상세하게는 RIT 공정을 이용한 광섬유 모재의 생산공정에서 1차프리폼과 2차 튜브 경계상에 발생하는 수분을 방지하는 방법에 관한 것이다.The present invention relates to a method for preventing boundary water generation in a RIT process, and more particularly, to a method for preventing moisture occurring on a boundary between a primary preform and a secondary tube in a production process of an optical fiber base material using the RIT process. will be.
일반적으로, 광섬유를 제조하는데 널리 쓰이고 있는 것은 미국특허 US4217027호에 개시된 MCVD(Modified Chemical Vapor Deposition)이다. 고순도의 광섬유를 제조할 수 있는 MCVD 공정에 대해 간략하게 설명하면, SiCl4, GeCl4, POCl3등의 액체가 담긴 버블러에 산소가스를 통과시킨 후, 기화된 화학기체를 석영튜브 내부로 유입시킨다. 석영튜브의 내부에 유입된 화학기체는 외부의 열원인 토치에 의해 가열된 석영튜브 내부를 흐르다가 반응 조건에 도달하게 되면 다음과 같 화학반응을 일으키게 된다.In general, it is widely used to manufacture optical fibers are Modified Chemical Vapor Deposition (MCVD) disclosed in US Pat. The MCVD process for manufacturing high purity optical fibers is briefly described. After passing oxygen gas through a bubbler containing liquid such as SiCl 4 , GeCl 4 , and POCl 3 , the vaporized chemical gas is introduced into the quartz tube. Let's do it. The chemical gas introduced into the quartz tube flows inside the quartz tube heated by a torch, which is an external heat source, and when the reaction conditions are reached, chemical reactions occur as follows.
SiCl4+ O2→SiO2+ 2Cl2 SiCl 4 + O 2 → SiO 2 + 2Cl 2
GeCl4+ O2→GeO2+ 2Cl2 GeCl 4 + O 2 → GeO 2 + 2Cl 2
상기와 같은 화학반응으로 생성된 수트 SiO2, GeO2는 내부기체와 함께 이동하다가 열원에 의해 가열되지 않은 열원 전방구간에서 열영동력(thermophoretic Force)에 의해 튜브내부에 증착하게 된다. 열원이 진행함에 따라 수트증착층은 층을 이루게 되며, 열원이 튜브를 왕복운동할 때마다 화학기체의 조성을 달리함으로써 수트입자 증착층의 굴절율을 조절하게 된다. 상기와 같은 공정을 반복하여 원하는 수의 증착층이 형성되면 컬랩스(collapse) 공정, 열수축을 이용하여 내부의 빈공간을 제거하여 1차프리폼을 만든다.The soot SiO 2 , GeO 2 produced by the above chemical reaction moves together with the internal gas and is deposited inside the tube by thermophoretic force in the front section of the heat source that is not heated by the heat source. As the heat source proceeds, the soot deposition layer forms a layer, and the refractive index of the soot particle deposition layer is controlled by changing the composition of the chemical gas whenever the heat source reciprocates the tube. When the desired number of deposition layers are formed by repeating the above process, a primary preform is formed by removing empty spaces by using a collapsing process and thermal contraction.
상기의 MCVD 공법은 CVD, VAD 등과 같은 다른 광섬유 제조 방법에 비해 고순도의 증착이 가능하다는 장점이 있지만, 동일한 이유에서 제조할 수 있는 양은 한정되는 문제점이 있었다.The MCVD method has the advantage of being capable of high purity deposition compared to other optical fiber manufacturing methods such as CVD, VAD, etc., but the amount that can be manufactured for the same reason has a limited problem.
따라서, 광섬유의 수요증가로 인해 MCVD 공정의 생산성을 높이는 방법이 개발되기 시작하였고, 이러한 방법들 중의 하나가 RIT(Rod in Tube) 공정이다. RIT 공정은 MCVD 공법으로 제조된 1차프리폼에 클래드부분을 추가하는 것으로서, 1차프리폼을 1차프리폼의 외경보다 큰 내경을 갖는 2차튜브에 삽입하고 토치로 가열하면서 2차튜브를 열수축, 컬랩스시켜서 일체화하는 것이다. 이때, 열수축 속도를 높이기 위해서 1차프리폼과 2차튜브의 내부를 외부압 보다 낮은 음압상태로 유지하고 열원인 H2/O2토치를 사용한다. 하지만, 내부를 음압상태로 유지하면 일체화 속도는 빨라지지만 최종 프리폼의 순도가 나빠지는 문제점이 발생하였다. 즉, 열수축을 위해 H2/O2토치를 사용하고, 1차프리폼과 2차튜브의 내부를 음압상태로 유지하면 공정 초반에 1차프리폼과 2차튜브의 경계가 외부로 노출된 상태에서 토치의 화염이 1차프리폼과 2차튜브의 경계 내부로 유입되어 프리폼의 외벽과 튜브의 내벽에 수분이 응결된다. 이렇게 응결된 수분은 최종 프리폼의 제조시 불순물로 존재하게 되며, 특히 1385nm 파장대에서 OH-기에 의해 발생되는 광손실을 초래하게 된다.Therefore, a method of increasing the productivity of the MCVD process has begun to develop due to the increased demand of optical fibers, and one of these methods is a rod in tube (RIT) process. The RIT process adds cladding to the primary preform manufactured by the MCVD method. The RIT process inserts the primary preform into a secondary tube having an inner diameter larger than that of the primary preform and heats the secondary tube while heating with a torch. To integrate. At this time, in order to increase the speed of heat shrinkage, the inside of the primary preform and the secondary tube are kept at a negative pressure lower than the external pressure, and a heat source H 2 / O 2 torch is used. However, if the internal pressure is maintained at a negative pressure, the integration speed is increased, but the purity of the final preform is deteriorated. In other words, if the H 2 / O 2 torch is used for heat contraction and the inside of the primary preform and the secondary tube are kept in a negative pressure state, the torch with the boundary between the primary preform and the secondary tube exposed to the outside at the beginning of the process The flame of is introduced into the boundary between the primary preform and the secondary tube, and water condenses on the outer wall of the preform and the inner wall of the tube. The condensed water is present as an impurity in the preparation of the final preform, and in particular, causes light loss generated by OH − groups in the 1385 nm wavelength band.
본 발명은 상기와 같은 문제점을 해결하기 위해 창안된 것으로서, 보조튜브를 사용하여 1차프리폼과 2차튜브의 경계영역을 봉합함으로서 불순물의 생성 및 유입을 방지할 수 있는 RIT 공정에서의 경계지점 수분 발생 방지 방법을 제공하는데 그 목적이 있다.The present invention was devised to solve the above problems, and the boundary point moisture in the RIT process that can prevent the generation and introduction of impurities by sealing the boundary region of the primary preform and the secondary tube using the auxiliary tube. Its purpose is to provide a method of preventing occurrence.
본 명세서에 첨부되는 다음의 도면들은 본 발명의 바람직한 실시예를 예시하는 것이며, 후술하는 발명의 상세한 설명과 함께 본 발명의 기술사상을 더욱 이해시키는 역할을 하는 것이므로, 본 발명은 그러한 도면에 기재된 사항에만 한정되어 해석되어서는 아니된다.The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to
도 1은 본 발명의 일 실시예에 따른 1차프리폼과 보조튜브를 나타낸 도면이다.1 is a view showing a primary preform and an auxiliary tube according to an embodiment of the present invention.
도 2는 본 발명에 따라 1차프리폼에 보조튜브를 접합하는 상태를 나타낸 도면이다.2 is a view showing a state in which the auxiliary tube is bonded to the primary preform according to the present invention.
도 3은 본 발명에 따른 1차프리폼과 접합된 보조튜브를 2차튜브에 접합하는 상태를 나타낸 도면이다.3 is a view showing a state in which the secondary tube bonded to the secondary tube bonded to the primary preform according to the present invention.
도 4 및 도 5는 본 발명에 따른 일측이 밀폐된 2차튜브의 내부를 음압상태로 유지하면서 컬랩스하는 상태를 나타낸 도면이다.4 and 5 is a view showing a state in which one side is collapsing while maintaining the inside of the sealed secondary tube in a negative pressure state.
도 6은 본 발명에 따라 제조된 프리폼을 나타낸 도면이다.6 is a view showing a preform manufactured according to the present invention.
상기와 같은 목적을 달성하기 위하여 본 발명에 따른 RIT 공정에서의 경계지점 수분 발생 방지 방법은 1차프리폼을 보조튜브에 삽입하고, 열을 가하여 보조튜브를 용융시키면서 1차프리폼과 보조튜브를 접합하는 단계, 접합된 1차프리폼과 보조튜브를 2차튜브에 삽입하고, 열을 가하여 용융된 보조튜브를 2차튜브의 일단에 결합하여 2차튜브의 개방된 단부 일측을 밀봉하는 단계, 상기 2차튜브의 단부 타측에 진공펌프를 연결하여 내부를 음압상태로 유지시키는 단계 및 열원을 이용하여 컬랩스하는 단계를 포함한다.In order to achieve the above object, the method of preventing boundary moisture generation in the RIT process according to the present invention inserts a primary preform into an auxiliary tube, and heats the auxiliary preform to join the primary preform and the auxiliary tube. Step, inserting the bonded primary preform and the auxiliary tube into the secondary tube, by applying heat to the molten secondary tube to one end of the secondary tube to seal one side of the open end of the secondary tube, the secondary Connecting the vacuum pump to the other end of the tube to maintain the inside in a negative pressure state and collapsing using a heat source.
바람직하게, 본 발명에 있어서 1차프리폼과 보조튜브의 접합은 보조튜브를 가열하여 용융시키면서 탄소봉을 사용하여 용융된 보조튜브의 일측을 1차프리폼에 밀착되도록 하며, 상기 2차튜브의 내부는 외부의 압력보다 낮은 음압상태로 유지되는 것을 포함한다.Preferably, in the present invention, the bonding between the primary preform and the auxiliary tube is such that one side of the molten auxiliary tube is closely adhered to the primary preform using a carbon rod while heating and melting the auxiliary tube, and the inside of the secondary tube is external. It includes maintaining a negative pressure lower than the pressure of.
이하 첨부된 도면을 참조로 본 발명의 바람직한 실시예를 상세히 설명하기로 한다. 이에 앞서, 본 명세서 및 청구범위에 사용된 용어나 단어는 통상적이거나 사전적인 의미로 한정해서 해석되어서는 아니 되며, 발명자는 그 자신의 발명을 가장 최선의 방법으로 설명하기 위해 용어의 개념을 적절하게 정의할 수 있다는 원칙에 입각하여 본 발명의 기술적 사상에 부합하는 의미와 개념으로 해석되어야만 한다. 따라서, 본 명세서에 기재된 실시예와 도면에 도시된 구성은 본 발명의 가장 바람직한 일 실시예에 불과할 뿐이고 본 발명의 기술적 사상을 모두 대변하는 것은 아니므로, 본 출원시점에 있어서 이들을 대체할 수 있는 다양한 균등물과 변형예들이 있을 수 있음을 이해하여야 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.
도 1 및 도 2는 본 발명의 일 실시예에 따른 1차프리폼(10)과 보조튜브(20)의 결합을 나타낸 도면이다. 여기서, 1차프리폼(10)은 종래기술에 기술한 것과 같이 MCVD 공법을 사용하여 제조된 프리폼이며, 보조튜브(20)는 클래드층과 같은 석영관의 재질로서 내경은 1차프리폼(10)의 외경보다 크고 후술할 2차튜브의 내경보다 크게 구성하는 것이 바람직하다.1 and 2 are views showing the combination of the primary preform 10 and the auxiliary tube 20 according to an embodiment of the present invention. Here, the primary preform 10 is a preform manufactured using the MCVD method as described in the prior art, and the auxiliary tube 20 is made of a quartz tube such as a cladding layer, and the inner diameter of the primary preform 10 is It is preferable to configure larger than the outer diameter and larger than the inner diameter of the secondary tube to be described later.
상기 보조튜브(20)를 1차프리폼(10)에 접합하기 위해서는 먼저, 1차프리폼(10)을 접합할 보조튜브(20)에 삽입하여 고정한다. 이때, 1차프리폼(10)과 보조튜브(20)는 서로 평행하도록 고정하는 것이 바람직하며, 고정된 상태에서 1차프리폼(10)과 보조튜브(20)를 회전시키면서 보조튜브(20)의 외부에 열을 가한다. 가열은 H2/O2토치(30)를 사용하며, 약 1000℃ 이상의 온도로 가열하여 보조튜브(20)를 용융상태로 만든 후, 상기 용융된 보조튜브를 탄소봉(40)을 사용하여 1차프리폼쪽으로 밀착시키면서 보조튜브(20)의 일단을 1차프리폼에 접합시킨다.In order to bond the auxiliary tube 20 to the primary preform 10, first, the primary preform 10 is inserted into and fixed to the auxiliary tube 20 to be bonded. At this time, the primary preform 10 and the auxiliary tube 20 is preferably fixed to be parallel to each other, the outer of the auxiliary tube 20 while rotating the primary preform 10 and the auxiliary tube 20 in a fixed state To heat. Heating uses a H 2 / O 2 torch (30), and heated to a temperature of about 1000 ℃ or more to make the auxiliary tube 20 in a molten state, the molten auxiliary tube is first used by using a carbon rod 40 One end of the auxiliary tube 20 is bonded to the primary preform while being in close contact with the preform.
도 3은 본 발명에 따른 1차프리폼(10)과 접합된 보조튜브(20)를 척(50)에 고정되어 있는 2차튜브(60)에 접합하는 상태를 나타낸 도면이다. 이를 참조하면, 1차프리폼(10)의 일단을 척(50)에 고정한 상태에서 2차튜브(60)에 서로 평행하도록 삽입하여 고정시킨다. 바람직하게는, 접합될 보조튜브(20)의 수직벽 종단과 2차튜브(60)의 개방된 종단을 서로 인접한 위치에 놓고, H2/O2토치(30)로 접합될 보조튜브의 종단을 약 1000℃ 이상으로 가열하여 용융시킨다. 가열후 어느 정도 보조튜브(20)의 수직벽 종단이 용융되어 점도가 낮아지면 1차프리폼(10)을 잡고 있는 척(50)을 소정간격 이동하여 2차튜브(60)에 물리적인 힘을 가하면서 접합한다. 본 발명에 따르면, 보조튜브(20)를 약 5mm 정도 2차튜브(60)에 가압하여 밀착시킴으로써 충분한 접합강도를 유지할 수 있다.3 is a view showing a state in which the secondary tube 60 bonded to the primary preform 10 and the secondary tube 60 fixed to the chuck 50 according to the present invention. Referring to this, in the state in which one end of the primary preform 10 is fixed to the chuck 50, the secondary tube 60 is inserted and fixed in parallel to each other. Preferably, the vertical wall end of the auxiliary tube 20 to be joined and the open end of the secondary tube 60 are positioned adjacent to each other, and the end of the auxiliary tube to be joined with the H 2 / O 2 torch 30 is positioned. It is heated to about 1000 ° C. or more to melt it. When the vertical wall end of the auxiliary tube 20 melts to some extent after heating, and the viscosity decreases, the chuck 50 holding the primary preform 10 is moved a predetermined interval to apply a physical force to the secondary tube 60. Bonding while. According to the present invention, sufficient bonding strength can be maintained by pressing the auxiliary tube 20 against the secondary tube 60 by about 5 mm.
본 발명에 따르면, 상기와 같이 일측이 밀폐된 2차튜브(60)가 완성되면 타측에 진공펌프(70)를 사용하여 2차튜브의 내부를 음압상태로 유지하면서 컬랩스단계를 진행한다. 이를 나타낸 것이 도 4 및 도 5이다. 2차튜브(60)로 사용되는 석영관의 연화점은 약 1700℃이므로, 바람직하게는 1800 ~ 1900℃로 토치의 온도를 유지하면서 2차튜브를 가열하면 1차프리폼(10)과 2차튜브(20) 사이의 공간은 열수축에 의해 수축되면서 내부를 충진하게 된다. 따라서, 일측이 밀폐된 2차튜브(60)는 열수축반응을 가속화시키기 위해 내부를 음압상태로 유지해도 종래기술과 달리 외부의 불순물이 내부 유입되지 않는다. 컬랩스 공정을 마친 완성된 프리폼을 도 6에 나타내었다.According to the present invention, when one side of the secondary tube 60 sealed is completed as described above, the vacuum tube 70 is used on the other side to maintain the interior of the secondary tube in a negative pressure state while performing the collapsing step. 4 and 5 illustrate this. Since the softening point of the quartz tube used as the secondary tube 60 is about 1700 ° C., the primary preform 10 and the secondary tube (1) are preferably heated when the secondary tube is heated while maintaining the temperature of the torch at 1800 ° C. to 1900 ° C. The space between 20 is filled by the inside shrinking by heat shrink. Therefore, the secondary tube 60, one side of which is sealed, does not introduce external impurities inside, unlike the prior art, even though the inside is maintained at a negative pressure to accelerate the heat shrinkage reaction. The finished preform after completing the Collabs process is shown in FIG. 6.
이상과 같이, 본 발명은 비록 한정된 실시예와 도면에 의해 설명되었으나,본 발명은 이것에 의해 한정되지 않으며 본 발명이 속하는 기술분야에서 통상의 기술사상과 아래에 기재될 특허청구범위의 균등범위 내에서 다양한 수정 및 변형이 가능함은 물론이다.As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this and is within the equal range of a common technical idea in the technical field to which this invention belongs, and a claim described below. Of course, various modifications and variations are possible.
본 발명의 RIT 공정에서의 경계지점 수분 발생 방지 방법에 따르면, 보조튜브를 사용하여 1차프리폼과 2차튜브의 경계영역을 봉합함으로서 불순물의 생성 및 유입을 방지하며, 나아가 경계영역에서 발생하는 수분발생을 방지함으로서 수분기에 의한 광섬유의 손실을 줄일 수 있다.According to the method of preventing boundary water generation in the RIT process of the present invention, the secondary tube is used to seal the boundary region between the primary preform and the secondary tube to prevent the generation and inflow of impurities, and furthermore, the moisture generated at the boundary region. By preventing the occurrence of the loss of the optical fiber due to the moisture can be reduced.
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KR20050071797A (en) * | 2004-01-02 | 2005-07-08 | 삼성전자주식회사 | Fabrication method for optical fiber preform |
KR100556316B1 (en) * | 2002-09-12 | 2006-03-03 | 엘에스전선 주식회사 | Method of RIT process for removing water in the gap of rod and tube |
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US6460378B1 (en) * | 2000-02-29 | 2002-10-08 | Xiaoyuan Dong | Collapsing a multitube assembly and subsequent optical fiber drawing in the same furnace |
KR100398070B1 (en) * | 2001-10-30 | 2003-09-19 | 엘지전선 주식회사 | Water bocking method in the interfacing surface during the joining of core and clad |
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KR100556316B1 (en) * | 2002-09-12 | 2006-03-03 | 엘에스전선 주식회사 | Method of RIT process for removing water in the gap of rod and tube |
KR20050071797A (en) * | 2004-01-02 | 2005-07-08 | 삼성전자주식회사 | Fabrication method for optical fiber preform |
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