JPS63182227A - Production of glass film and device therefor - Google Patents

Abstract

PURPOSE:To produce a light guiding film low in propagation loss by feeding gas flow led along the direction of an exhaust pipe to the vicinity of a synthetic torch in a device consisting of both the synthetic torch for fine glass particles and the exhaust pipe of flame laminar flow contg. excess fine glass particles. CONSTITUTION:An air supply pipe 13 wherein an air inlet I and an exhaust port E are integrated for example, to control the flow direction of air is provided so as to cover laminar flow 12 led to the exhaust direction of the flame 12 and the exhaust port E is connected to an exhaust pipe 6. When feeding the laminar flow 12 contg. fine glass particles through a synthetic torch 5, it is introduced into the air supply pipe 13 from a window W1 and directly blown on a base plate 1 via a window W2. After depositing the fine glass particles on the base plate 1, the lamina flow 12 is sucked with an exhaust gas treatment device and exhausted from the exhaust port E through the exhaust pipe 6 and an exhaust control valve 14. At this time, negative pressure is caused in the part of the direction opposite to the exhaust direction of the laminar flow 12 of the air supply pipe 13 and atmospheric gas e.g. air is introduced through the air inlet I and gas flow is generated to the exhaust direction of the laminar flow 12.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field of the Invention) The present invention relates to a method for manufacturing a glass film and a TM production apparatus thereof. The present invention relates to a method for forming a glass leading wave film having a wide range of applications in the field of communication components, and to a method for manufacturing a glass film with uniform thickness and glass composition, and an apparatus for carrying out the method.

[Prior art to the invention]

Silica-based glass guide waveguides that can be formed on silica glass substrates or silicon substrates are expected to be a means of realizing practical waveguide optical components because of their good compatibility with silica-based fibers. In order to form a high-quality quartz-based optical waveguide on the substrate, there are two techniques: (1) a technique for depositing a glass film with a uniform thickness on the substrate; (2) a technique for suppressing compositional fluctuations of the glass film as much as possible;
It is essential to develop a manufacturing method for a silica-based leading wave film that satisfies the following two factors.

As a result of conducting studies in line with the above objectives, the present inventors found that:
As a manufacturing method that satisfies the requirements of
51) No. 1)] was proposed. An example of the configuration of an apparatus for carrying out this method is shown in FIG.

To manufacture a leading wave film using this device, first arrange the substrates l on the turntable 2, raise the substrate temperature (the heater for heating the substrate is installed at the bottom of the turntable 2), and place the substrate l on the turntable 2. The turntable 2 is rotated by the rotation device 3. Next, the raw material gas supply device 9
02 gas and I+ are passed from the raw material gas conduit 10 to the glass particle synthesis torch 5 (hereinafter simply referred to as l・-chi).
2 gases are supplied to form an oxyhydrogen flame at the blow-off part of the torch, and the flame is blown onto the substrate 1. At the same time, the torch 5 is moved parallel to the turntable 2 in the radial direction by the torch moving device 8. Desired substrate temperature (600-800℃)
When the frit gas is sent from the raw material gas supply bag rI19 to the torch 5, a hydrolysis reaction occurs in the flame.
Glass particles are deposited on the substrate 1. The structure is such that the excess gas particles are exhausted to the exhaust gas treatment device 7 through the exhaust pipe 6 along with the flame flow.

Normally, the structure of an optical waveguide film is a multilayer structure in which a buffer layer, a core layer, and a protective layer are arranged on the substrate 1, so the torch 5
The glass particles are deposited by changing the composition of the frit gas supplied to the glass according to a predetermined plan.

FIG. 2 shows a schematic diagram of the deposition area of glass particles, which plays the most important role in the quality of the optical waveguide film produced by the method shown in FIG. 1. In FIG. 2, the key to manufacturing a high-quality optical waveguide film is to deposit glass particles on the substrate 1 while the surface of the substrate 1 is exposed to a flame laminar flow 12 containing the glass particles.

In order to achieve a laminar flame flow containing glass particles, it is essential to have a gi-performing torch arrangement and a method for exhausting excess glass particles that are not deposited on the substrate surface. Realization is the main focus of the optical waveguide film manufacturing method proposed earlier. That is, in FIG. 2, the torch 5 is installed at a desired angle θ with respect to the substrate surface, and the blowing direction of the flame laminar flow 12 containing fine glass particles formed at the tip of the torch 5 and the substrate 1 are adjusted. Glass particles can be deposited on the substrate surface while maintaining flame laminar flow 12 by providing an exhaust pipe 6 on the downstream side of the flame laminar flow 12 that matches the moving direction and quickly exhausts excess glass particles that are not deposited on the substrate surface. This is the way to do it. Note that reference numeral 1) is an optical pyrometer for measuring the temperature on the substrate.

[Problems to be solved by the invention]

As a result of repeated experiments regarding this conventional manufacturing method, the following problems were found.

1) Figure 3 shows a schematic diagram of the equipment arrangement and air flow seen from arrow A in Figure 2. Note that the torch is omitted. In FIG. 3, the flame flow 12 exposes the substrate 1 surface while maintaining a laminar flow state, and is exhausted to the exhaust pipe 6 while spreading slightly on the substrate 1 surface.

During this process, the air flow is as shown by the dashed arrow in the figure.
Flows from around the exhaust port toward the exhaust port.

In this way, the flame flow 12 is a unidirectional flow, whereas the air flow flows toward the exhaust port from all directions, so when some kind of disturbance occurs, the air flow changes, and this causes the flame to flow in one direction. The problem is that the flow does not maintain a laminar flow, or it becomes momentarily turbulent, causing the entire flame to waver.

This causes layered striae to occur in the glass film formed on the substrate surface, deteriorating the optical properties of the leading wave film.

2) The quality of the leading wave film formed on the substrate 1 depends on the angle θ formed between the substrate 1 surface and the torch 5 (strictly speaking, the angle formed between the substrate surface and the flame laminar flow) shown in Fig. 2. However, if the angle θ is small, the adhesion efficiency of glass particles will deteriorate significantly, and if the angle θ is large, for example, as shown in FIG.
In the case of 90'', the flame laminar flow 12 spreads uniformly on the substrate surface, becomes turbulent at part a shown in the figure, and at the same time
There is a problem that only the side flame is exhausted. Also,
There are parts where flocculent glass particles are deposited, and this causes a problem in that cracks occur in the deposited porous glass film. According to the inventors' study, the angle θ is 65° to 7
5° is optimal, and outside this range the above problem will occur.

3) In the prior art, the laminar flow state was maintained by matching the substrate movement direction and the incident direction of the flame laminar flow 12. Considering the miniaturization of the manufacturing equipment design, it is possible to manufacture a high-quality leading wave film without causing local turbulence even if the substrate movement with respect to the incident direction of the flame laminar flow 12 is repeated in the forward and reverse directions. desirable. According to the studies of the present inventors, even in the conventional technology, by optimizing conditions such as the torch angle θ, the exhaust flow direction, the distance between the substrate surface and the torch tip, and the installation position of the exhaust pipe, the substrate can be moved in the opposite direction. High quality leading without local turbulence of flame laminar flow? Although it has been confirmed that a tL membrane can be produced, it has the drawback that it is very difficult to optimize the conditions described above to prevent turbulence from occurring.

The present invention provides means for controlling the air flow as much as possible in the direction in which the laminar flame flow is sucked into the exhaust port in FIG. 3, thereby solving the problems of the prior art and reducing disturbance. The present invention provides a method of manufacturing a silica-based glass film, particularly a high-quality leading wave film, and an apparatus for carrying out the method, which always realizes a stable flame laminar flow state regardless of the torch installation angle θ.

[Means for solving problems]

The inventors of the present invention clarified the problems of the prior art and studied various means for solving the problems.The inventors found that in order to prevent the fluctuations of flame laminar flow and local turbulence, which are problems of the prior art,
We have discovered that this problem can be solved by making the flame laminar flow and the air flow exhausted to the exhaust port in the same direction as much as possible, leading to the present invention. That is, the method for manufacturing a glass film according to the present invention is a method for manufacturing an optical waveguide film that includes a torch, a flame laminar flow formed at the tip of the torch, and an exhaust port for quickly exhausting the flame laminar flow downwardly. In this method, means for controlling the direction of air flow or means for causing an externally controlled gas flow to flow along the direction of flame flow is used.

Therefore, according to the glass film manufacturing apparatus according to the present invention, the glass particle synthesis torch is arranged to directly blow glass particles onto the substrate from above, and the excess glass particles that have not adhered to the substrate are exhausted from the vicinity of the substrate. The glass film manufacturing apparatus is characterized in that a gas supply section is provided near the synthesis torch.

According to the method of the present invention, the gas flow is caused to flow along the flame laminar flow as described above, and this gas flow is caused to flow along the flame laminar flow flowing in the exhaust direction among the flame laminar flows. It is not necessary to flow along the entire flow of the flame laminar flow from the synthesis torch 5 to the exhaust gas. Furthermore, as will be described later, the mechanism for generating the gas flow along the flame laminar flow 12 is not fundamentally limited in the present invention, and for example, a gas blowing device may be provided to form the gas flow. Alternatively, the gas flow along the flame laminar flow 12 may be formed by changing the atmospheric pressure of the glass film forming atmosphere without forming the gas blowing device section (see FIGS. 6, 7, and 8). (See Figure 5).

FIGS. 5 to 8 show schematic diagrams of embodiments of the present invention.

It should be noted that the present invention is not limited to these embodiments. 5 and 6 show examples of controlling the direction of air flow, and air supply pipes 13 to 15 are provided to control the air flow.

In particular, the method shown in FIG. 5 has a gas supply section that is an air supply pipe 13 that integrates an air supply port (2) and an exhaust port (E). The air supply pipe 13 is provided in the exhaust direction of the flame laminar flow 12 so as to cover the flame laminar flow 12.

This air supply pipe 13 has a glass particulate synthesis torch window W1 at the top into which the tip of the synthesis torch 5 can be inserted, and a substrate at the bottom so that the glass particulates can be directly sprayed onto the surface of the substrate 1 on which the glass particulates are deposited. It has a structure with 2 windows for use. The exhaust port E is connected to an exhaust pipe 6,
The exhaust pipe 6 is connected to an exhaust gas treatment device 71 (see FIG. 1) via an exhaust control valve 14.

On the other hand, the air supply port I of the air supply pipe 13 is in an open state.

Because of this configuration, when the flame laminar flow 12 containing glass particles is supplied from the synthesis torch 5, the flame laminar flow 1
2 is introduced into the air supply pipe 13 through the synthetic torch window W1,
It is sprayed directly onto the substrate 1 through the substrate window 2. After depositing the glass particles on the substrate 1, the flame laminar flow 12 is sucked by the exhaust gas treatment device i+27 and exhausted from the exhaust port E through the exhaust pipe 6 and the exhaust control valve 14. At this time, the flame laminar flow 1 of the air supply pipe 13
Since the part in the direction opposite to the exhaust direction of No. 2 is in a negative pressure state and the air supply port I is in an open state, atmospheric gas, such as air, flows in from the air supply port II, causing the flame laminar flow 12. It will flow along. That is, a gas flow is generated in the exhaust direction of the flame laminar flow 12, and as a result, it becomes possible to flow the gas flow in the exhaust direction of the flame laminar flow 12. Note that the flow rate of gas flowing into the air supply pipe 13 from the air supply port I can be controlled by the exhaust control valve 14.

Furthermore, in the case where such an air supply pipe 13 is provided, since the gas flow is formed by suctioning atmospheric gas, for example, air into the air supply pipe 13 under negative pressure, there is a risk that dust and the like in the atmosphere may be sucked together. There is. For this reason, it is preferable to provide a filter or the like at the air supply port (2) of the air supply pipe 13 to purify the gas flow flowing along the flame laminar flow 12.

According to this method, an extremely stable flame laminar flow state can be achieved without causing flame turbulence even when the torch angle θ is 90°, which was impossible with the prior art.

Further, FIG. 6 shows a structure in which a gas supply section, which is an air supply pipe 15, which blows out gas such as air, is provided in the exhaust direction of the flame laminar flow 12. That is, unlike the embodiment shown in FIG. 5, the air supply pipe 15 blows out a gas such as air, and the blown gas flow follows the flame laminar flow 12. With this configuration, after the flame laminar flow 12 is blown onto the substrate 1, it enters the exhaust pipe 6 together with the gas flow blown out from the air supply pipe 15,
It will be exhausted through exhaust control ``$14''.

FIGS. 7 and 8 show examples having a gas supply section that allows a controlled gas flow to flow from the outer periphery of the torch or from the sides of the torch along the direction of flame flow. θ can be relaxed, and the problem of fluctuations in the flame laminar flow 12 due to disturbances can be solved. That is, the synthesis torch 5 is shown in FIGS. 7(a), (bl,
As shown in (C) and (d), the gas outlet 16.16' is located on the outer side of the oxygen, hydrogen and glass particle outlet.
, 16'', making it possible to blow out a gas flow along the flame 12. Therefore, the gas such as air from the gas outlet 16.1G', 16' is Unlike the embodiments shown in FIGS. 5 and 6, the laminar flame flow not only follows the laminar flame flow 12 flowing in the exhaust direction, but also blows against the substrate 1 along the laminar flame flow 12 from the beginning of the blowout, causing the laminar flame flow to flow along the exhaust direction. 12 and is exhausted from the exhaust pipe 6 (see FIG. 7 (1)).

In the example shown in FIG. 8, a gas outlet 16 is provided concentrically on the outermost side of the various outlets of the synthesis torch 5, and is similar to the embodiment shown in FIG. , the gas flow flows from the beginning along the flame flow 12 and reaches the exhaust pipe 6.
It has a structure that allows for more exhaust air.

That is, in the present invention, as described above, the flame laminar flow 1
2, the gas flow may be made to follow the flame laminar flow 12 portion flowing in the exhaust direction. Therefore, even if the gas flow is made to follow the synthesis torch 5 portion, the gas flow will similarly follow the flame laminar flow 12 portion flowing in the exhaust direction, and the same effect can be obtained.

Embodiments of the present invention will be described in detail below with reference to FIGS. 5 to 8. In the present invention, there is no problem with the conventional apparatus configuration shown in FIG. 1 except for having the gas supply section shown in FIGS. 5 to 8, so the explanation will be made with reference to FIG. 1 as well.

(The following is a blank space) Example 1 In FIG. 1, an air supply pipe 13 in which an exhaust port (2) and an air supply port E were integrated as shown in FIG. 5 was installed to deposit glass particles. The air supply pipe 13 is made of quartz glass, and its dimensions are width 7c1), height 5cim, and length 30cm.
and a 2c1) x 5c1) torch placement window-1 on the top surface.
) The structure has a glass particulate deposition window edge 2 of 7c+aXIQcm on the lower surface, and an exhaust amount control valve 14 is provided on the downstream side of the exhaust port. The air supply pipe 13 was arranged so that the distance between the lower surface of the air supply pipe and the surface of the substrate was three fins, and the amount of air supply and exhaust was adjusted by the exhaust amount control valve 14.

A silicon substrate with an outer diameter of 75 fins and a thickness of 0.7 m was used as the substrate 1, and 10 silicon substrates were placed on a turntable with a radius of 50 CIl. The deposition conditions for glass particles are: turntable rotation speed, 5γpm torch movement speed.
1mm/sec torch movement stroke 150mmO2 gas supply amount
6I! /min II 2 gas supply amount
31/min substrate temperature
The temperature was 700°C. Note that the direction of rotation of the turntable and the direction of flame flow were made to match. Inside the raw material gas supply device 9, a main raw material 5iC1a, a dopant GeCl4, and a PC are contained in a bubbler housed in an electronic thermostat.
I 3 and BCI 3 were stored in a cylinder, mixed with the following raw material compositions by a flow rate control mechanism, and supplied to the torch.

Buffer layer 5iC14100cc 7 minutes [IBr 3
5cc 7min PCl 35cc 7min Core layer 5iC14100cc/min GeCl4
12cc 7 min PCI 32cc 7 min protective layer 5LCIa 100cc/min BBr
3 5cc 7 minutes PCI 3 5cc 7 minutes The deposition time for each is 30 minutes for the buffer layer, 15 minutes for the core layer.
0 minutes, and protective layer 60 minutes.

Deposition was performed while keeping the above conditions constant and using the torch installation angle θ as a parameter. That is, the glass particles were deposited while changing the angle θ from 30'' to 90'' in 5° increments. Although it is possible to form a film with θ=30° or less, the deposition efficiency of fine particles will be significantly degraded, so from a practical point of view it is preferable to set the value to 30” or more. Upon careful observation, we found that the momentary fluctuations in the flame laminar flow due to disturbances that occurred in the past were not observed at all, and an extremely stable flame laminar flow was obtained. There was no effect on the flame laminar flow even when the flame flow was generated (by blowing outside air with a blower). A pressure sensor with an accuracy of ±0.1 Tsuru 1)20 was introduced in the downstream part of the flow to detect pressure fluctuations in the air supply pipe during the deposition process.

As a result, the pressure inside the supply/exhaust port was 6.5 ml 20, and the fluctuation range was completely unaffected by the torch angle θ and disturbances and was below the accuracy of the sensor. For comparison, when we detected the pressure in the downstream part of the flame flow using a conventional technology in which only an exhaust pipe was installed, the average pressure was -7.8 soil 1.2 HI +2
0 fluctuation, momentarily -7.8 soil 2.9 mm1)
It fluctuated up to 20. Also, the fluctuation range is 90° when the torch angle θ is
” grew larger as it approached.

In the embodiment, the situation when the torch angle θ is 90° is shown in FIG. 9. As shown in FIG.
Even if the angle is 90°, the problem of partial turbulence in the flame flow (
Figure 4) was not observed, and an extremely stable laminar flame flow was achieved.

Porous glass membrane deposited as above (triple structure)
was mixed with He and 02 gas at 10:1 in a separately prepared electric furnace.
It was made into transparent glass in a mixed gas atmosphere. Note that the electric furnace temperature was maintained at 1380'C. The thickness of the obtained leading wave film is, for example, when the angle θ=70°, the buffer layer is 10 crm.
The thickness of the core layer was 50 μm, and the thickness of the protective layer was 20 μm.

The measurement limit of the measurement system used to measure the propagation loss of the optical waveguide film manufactured in this manner is 0.0 IdB/cm). The results of the relationship between the torch angle θ and the propagation loss are shown in FIG. Furthermore, for comparison, FIG. 10 also shows the propagation loss of an optical waveguide film manufactured using the conventional technique. The propagation loss of the leading wave film according to the present invention shown by the solid line is as follows when the torch angle θ ranges from 30' to 90'.
Measurement limit of 0.01 dB/c over a wide angle range of °
It was n+ or less. On the other hand, in the conventional technology shown by the dotted line, angular dependence of loss is seen, and the loss is relatively low at 0.02 to 0.04 dB/ell up to θ of about 80°, but when θ is 80° If it exceeds 9, the loss starts to increase and
At 0゛, it was 3 dB/c1). Moreover, cracks occurred in 6 of the porous glass films deposited on 10 silicon substrates at θ=90°.

In this way, the method of maintaining the flame laminar flow stably, for example, by arranging the air supply pipe as described in the embodiment of the present invention, is extremely stable without being influenced by disturbances around the glass particulate deposition area or even by the torch angle. Since a laminar flame flow can be realized, it is possible to obtain a porous glass thin film in which the thickness of each layer is uniform and the fluctuation in dopant concentration is extremely small.As a result, a wide angular range can be obtained as shown in Figure 10. So 0.
This means that an optical waveguide film with a low propagation loss of 0.01 dB/cm or less was obtained. When the torch angle θ is 30° or more, a high-quality optical waveguide film can be produced regardless of the angle θ, which not only greatly eases the deposition conditions for glass particles (but is also advantageous in terms of the deposition efficiency of glass particles). Figure 1) shows the relationship between the torch angle θ and the glass particle deposition efficiency. The deposition efficiency improves as the angle θ increases, and when the angle θ is 90
It reaches 90% at °. Therefore, as described in the examples, the present invention, which can produce a high-quality leading wave film even at θ-90', has the advantage of being able to produce a high-quality film with high efficiency.

In the above embodiment, the moving direction of the substrate and the incident direction of the flame laminar flow are the same direction, but the torch installation angle θ is set to 30
, 45°, 60°, 75°, and 90°, and the buffer layer, core layer, and protective layer were deposited with the moving direction of the substrate opposite to the incident direction of the laminar flame flow. An extremely stable flame laminar flow was achieved without the instantaneous fluctuations of the flame laminar flow or the partial turbulence of the flame laminar flow depending on the angle θ, which were observed in . Further, the propagation loss of the optical waveguide film manufactured in this manner was 0.01 dB/(maximum) or less at any torch angle, which was a good result.

Embodiment 2 In FIG. 6, the outlet size of the air supply pipe 15 is 501φ.
30n from the position where the flame laminar flow 12 contacts the substrate surface.
The tip of the air supply pipe 15 is installed in front, and the pressure inside the air supply pipe 15 is -4ml I! Compressed air was supplied from the supply side so that the temperature was 0. In addition, the exhaust port is installed 120 mm behind the torch tip, and the pressure inside the exhaust pipe 6 is 6.0 mml 2.
The displacement control valve 14 was adjusted so that it became 0. In this installed state, glass particles were deposited under the same conditions as the glass particle deposition conditions described in Example 1. As a result, the flame laminar flow was stabilized, and the propagation loss of the obtained optical waveguide film was also 0.02 dB/cm in the range of torch installation angle θ=30° to 90°. In the example, when a disturbance was intentionally caused around the part where the glass particles were deposited, slight fluctuations occurred in the flame laminar flow. This is Example 1
This means that it is more susceptible to external disturbances than the integrated air supply and exhaust type, and this suggests that the flame laminar flow fluctuated slightly during the glass particle deposition process, resulting in variations in propagation loss.

In this embodiment, it is important to adjust the exhaust volume of the exhaust pipe 6 to be larger than the gas supply volume supplied to the air supply pipe 15. If the exhaust volume is small, some of the glass particles that are not deposited on the substrate surface At the same time, the flame flow spreads toward the air supply port side, and the effect of the present invention is lost.

Example 3 Glass particles were deposited using a torch having a flame-forming gas and a separate gas outlet 16 on the side surface of the torch 5 as shown in FIG. 7(b). During this process, gas outlet 1
Compressed air was flowed from 6 to 101/min, respectively. Other deposition conditions were the same as in Example 1. As a result, the flame laminar flow is not disturbed by external disturbances, and even when the substrate movement direction is opposite to the direction of incidence of the flame laminar flow, it is an extremely stable flame laminar flow, and there are no drawbacks of the conventional technology. Ta.

However, if the torch installation angle θ is 90°, the exhaust volume at the exhaust port must be slightly increased, and if the exhaust volume is the same as when θ is 90" or less, the laminar flame flow will Turbulent flow sometimes occurred in the upstream area where it touched the water.

According to the pressure inside the exhaust pipe, -551 when θ is 90° or less)
1) In the case of 20, -6,1mall 2 at θ-90°
0 was iJ. If the exhaust pressure is higher than this, the deposition efficiency of glass particles will deteriorate, which is not preferable.

The propagation loss of the optical waveguide film thus manufactured was 0.01 dB/cm or less when the angle θ was 30° or more. Note that θ
When the displacement was not adjusted at =90°, the loss was 0.03 dB/am, which was a slight deterioration.

Increasing the flow rate of gas blown out from the gas outlet is not preferable because this will disturb the flame laminar flow. The gas flow rate at which turbulence occurs varies depending on the dimensions of the torch cross section that forms the glass particles and the flame, but it is shown in Figure 7 (b).
) If the outside diameter of the torch shown in ) is 15 fins, the rate of
Turbulence began to occur in the compressed air. Note that the shape of the gas outlet on the side of the torch and the shape of the torch are as follows.
Even with the structures shown in Figures (C) and (d), the effect of the present invention is (b)
).

Example 4 Fine glass particles were deposited using a torch having a gas outlet 16 to maintain a stable flame laminar flow on the outermost periphery of the torch 5 that forms glass particles and flame as shown in FIG. 8(b). . During this process, compressed air was flowed through the gas outlet at a rate of 15/min. As a result, there is no disturbance in the flame laminar flow (there are no drawbacks of the prior art). However, in this example, as in Example 3, slight turbulence in the flame laminar flow occurred when the torch angle θ was 90°. However, by adjusting the displacement, we were able to improve the turbulence. The propagation loss of the optical waveguide film manufactured in this way is 0.0 at angle θ = 30° or more.
This was a good result of 1 dB/co+ or less. Since turbulence in the flame laminar flow begins to occur when the gas flow rate blown out from the gas outlet 16 exceeds 251/min, the present invention can be achieved by setting the gas flow rate below at which turbulence begins to occur, taking into account the cross-sectional dimensions of the torch. effect will be maximized.

In addition to the above embodiments, embodiments 2 and 3 and embodiments 2 and 4 can be combined and implemented. In this case, there is no need to adjust the displacement when the torch installation angle is θ-90'', and the flame laminar flow can be further stabilized than in the previous embodiment.

In addition, in Example 2.3.4, compressed air was used as the control gas for the flame laminar flow, but inert gas such as Arz N 2,
Any controlled gas for maintaining flame laminar flow may be used, such as nonflammable gas such as 02, CIII, etc., and the present invention is not limited to these types.

〔Effect of the invention〕

As explained above, according to the present invention, which is characterized by providing a means for stably maintaining the flame laminar flow formed at the tip of the torch, specifically, an air supply port for flame stabilization,
The disadvantages of the prior art were ■instantaneous fluctuations in the flame laminar flow, ■deterioration of propagation loss depending on the torch installation angle θ, partial turbulence of the flame at θ=90°, and problems with flame exhaust. These problems can be solved, and propagation loss can be further reduced. Therefore, in carrying out the present invention, a high-quality leading wave film can be manufactured at any angle as long as the first-chip installation angle θ is 30" or more, and as described in the examples, the flame layer This method has the advantage that high-quality optical waveguide films can be manufactured without any problems even when the direction of flow and substrate movement are opposite to each other.

Note that in the present invention, the substrate is moved relative to the torch, and glass particles are deposited homogeneously on the substrate by moving the torch, exhaust port, and air supply port without moving the substrate at all. It should be noted that the manufacturing method is also included within the scope of the present invention.

[Brief explanation of the drawing]

Figure 1 is a side view of the configuration of the manufacturing equipment using the conventional method, Figure 2 is a diagram showing the situation in which glass particles are blown onto a substrate using the conventional method, and Figure 3 is a view taken from arrow A in Figure 2. FIG. 4 is a diagram showing the situation when the angle θ=90'' in FIG. Figure 6 is a diagram showing an embodiment of the present invention in which an air supply port is installed, and Figure 7 <a) is a diagram showing an example of an embodiment of the present invention in which an air supply port is installed on the side of the torch. A diagram showing an embodiment of the present invention, FIG. 7(b) is an embodiment diagram showing a cross section of a torch provided with an air supply port, and FIG. 8(a) is a diagram showing an embodiment of the torch provided with an air supply port on the outer circumference of the torch. A diagram showing an example of an embodiment of the present invention provided, FIG. 8(b)
shows a cross section of a torch provided with an air supply port - an embodiment diagram,
Figure 9 is a diagram showing the situation when the angle θ = 90° in the embodiment of the present invention, Figure 10 is a diagram showing the relationship between the torch angle θ and propagation loss, and Figure 1) is a diagram showing the relationship between the torch angle θ and the deposition efficiency. It is a diagram showing the relationship. 1... Board, 2... Turntable, 3...
・Rotating device, 4... Protective container, 5... Gatas fine particle synthesis torch, 6... Exhaust pipe, 7... Exhaust gas treatment device, 8... Torch moving device, 9... Raw material gas Supply device, 10... Conduit, 1)... Optical pyrometer, 12... Flame flow, 13... Air supply pipe, 14... Displacement control valve, 15... Air supply pipe, 16, 16', 16
″、・・・Gas outlet applicant agent Amemiya
Seasonal Figure 2 Figure 3 Figure 5 Figure 6 (a) (b)
(C) (d) Figure 8 (b)! 6 Figure 9 to figure ool- Toner angle shallow θ (shallow) 1) Figure top - thousand angle jθ

Claims (4)

[Claims] (1) Glass particles synthesized by a glass particle synthesis torch are directly blown onto the substrate as a flame laminar flow, and the flame laminar flow containing excess blown glass particles is exhausted to form a porous glass on the substrate. A method for producing a glass film in which a layer is formed and then turned into transparent vitrification at a high temperature, characterized in that a gas flow is caused to flow along the exhaust direction of the flame laminar flow containing at least the surplus glass particles. Method. (2) A glass particle synthesis torch is arranged to blow a flame laminar flow containing glass particles directly onto the substrate from above, and a flame laminar flow containing surplus glass particles that did not adhere to the substrate is exhausted from near the substrate. 1. A glass film manufacturing apparatus comprising an exhaust pipe, characterized in that a gas supply section is provided in the vicinity of the synthesis torch, which can supply at least a gas flow along the direction of the exhaust pipe of the flame laminar flow. (3) The gas supply section is an air supply pipe having a gas supply port at one end and an exhaust port at the other end, and a glass particle synthesis torch window for blowing a flame laminar flow into the air supply pipe on the side surface of the air supply pipe; 3. The glass film manufacturing apparatus according to claim 2, further comprising a substrate window for depositing glass particles, which is opened on the opposite side so that the flame laminar flow is blown onto the substrate. (4) The glass film manufacturing apparatus according to claim 2, wherein the gas supply section is provided on a side surface of a glass particle synthesis torch or on the outermost periphery of the torch.