JPH08262252A - Production of optical waveguide film - Google Patents

Abstract

PURPOSE: To provide a process for producing an optical waveguide film capable of forming optical waveguide films of a uniform film thickness. CONSTITUTION: Substrates 4 are placed on a rationally moving turntable 6. A torch 3 which moves linearly back and forth on a diameter line R is disposed apart spacings from the substrates 4 on the front surface side of the substrates 4, independently from the turntable 6. Laminated particle layers are formed on the surfaces of the substrates 4 by injecting glass particulates to the surfaces from the torch 3 which controlling the moving speed vb(t) of the torch 3 in such a manner that the speed is inversely proportional to the distance r(t) of the torch 3 from the center C of rotation of the turntable in accordance with the control equation of vb(t)=(r0 /r(t)).vb0 . The moving speed of the torch 3 is controlled by polynomial expansion of the distance r(t) of the torch 3 in the equation of r(t)=r.(1±vb0 .t/r0 ).(1-ax-bx<2> -cx<3> -dx<4> ) from the control equation of the torch moving speed vb(t) as X= vb0 .t/r±vb0 .t)}<2> to determine respective constants (a) to (d) and applying these constants into the control equation of the moving speed of the torch.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an optical waveguide film, which is manufactured by laminating thin films of, for example, glass fine particles.

[0002]

2. Description of the Related Art FIG. 1 shows an example of an apparatus for producing an optical waveguide film by laminating thin films of glass particles or the like. In the figure, on the upper side of the chamber 9, a donut-shaped rotary table 6 that performs a rotary motion in the direction A in the figure by a table rotating mechanism (not shown) is arranged, and the doughnut-shaped rotary table 6 is evenly arranged on the rotary table 6. A plurality of circular substrates 4 are placed via the heating plate 8. In FIG. 1, the torch 3 and the exhaust pipe 5 are drawn sideways on the upper side of the rotary table 6 for ease of explanation, but in reality, the torch 3 having a small diameter for ejecting fine glass particles is ejected. The holes are arranged so as to face the substrate 4 with a gap therebetween, and the exhaust pipe 5 is provided so as to face the fine particle ejection port 11 of the torch 3.

The torch 3 is supplied with a raw material gas such as SiCl ₄ and a supporting gas and a combustible gas such as O ₂ and H ₂ from a raw material supply system. A deposit such as SiO ₂ synthesized in the flame 10 can be deposited and formed on the surface side of the substrate 4. Further, the exhaust gas generated during the synthesis of the deposit is guided to the exhaust gas processing system through the exhaust pipe 5 and exhausted.

This torch 3 is independent of the rotary table 6 and within a specified range on the radial line R passing through the position of the center of rotation C of the rotary table 6 (from slightly inside the inner circumference 14 to the outer circumference 13 of the rotary table 6). In the fine particle layer deposition apparatus 15 having the torch 3 and the exhaust pipe 5, a torch moving mechanism (not shown) is provided. The torch moving mechanism is provided with a control unit that controls the moving speed of the torch 3.
At the time t from the position of the center of rotation C of the rotary table 6 to the initial position of the torch 3, the distance in the radial line R direction is r ₀ , the initial moving speed of the torch 3 is vb ₀ . The distance in the radial direction R to the position of the torch 3 is r (t), and the moving speed of the torch 3 at time t is v.
When b (t) is set, the moving speed of the torch 3 is controlled based on the control equation shown in the following equation (1).

Vb (t) = dr / dt = (r ₀ / r (t)) · vb ₀ (1)

In other words, the moving speed vb (t) of the torch 3 at the time t is the distance r (t) in the radial line R direction from the position of the rotation table rotation center of the torch 3 at the time t.
It is designed to be controlled in inverse proportion to.

When an optical waveguide film is manufactured using this apparatus, the table rotating mechanism (not shown) is used to rotate the rotary table 6 in the direction A of the drawing while the torch moving mechanism (not shown) is used. Based on the above formula (1),
The moving speed vb (t) of the torch 3 is controlled and moved so as to be inversely proportional to the distance from the rotation center position of the rotary table 6 in the radial line R direction. Then, while performing this controlled movement, the torch 3 ejects the fine particles for forming a waveguide onto the surface of the substrate 4 to form a unit fine particle layer, and this operation is repeated a plurality of times to form a laminated fine particle layer. After that, the substrates 4 on which the laminated fine particle layer is formed are collectively housed in a furnace or the like,
Heat treatment is performed at a high temperature in a furnace or the like to make fine particles for forming a waveguide, such as glass fine particles, transparent to form an optical waveguide film.

When the moving speed vb (t) of the torch 3 is controlled, if the rotation angular speed of the rotary table 6 at time t is ω (t), then vb (t) << r (t) ω
Make the relationship of (t) hold. Further, the angular velocity of the rotary table 6 may be a constant rotational angular velocity, or may be inversely proportional to the distance r (t) in the radial line R direction from the rotary table rotation center position of the torch 3 at time t. . When the initial angular velocity of the rotary table 6 is ω ₀ , the rotary table angular velocity ω (t) when the rotary table 6 moves at a constant rotary angular velocity becomes the angular velocity shown in the following equation (2), while the rotation of the torch 3 The rotation table angular velocity ω (t) when rotating so as to be inversely proportional to the distance r (t) from the table center position is the angular velocity shown in the following expression (3).

Ω (t) = ω ₀ (2)

Ω (t) = (r ₀ / r (t)) · ω ₀ = (r ₀ · ω ₀ ) / r (t) (3)

[0011]

However, when an optical waveguide film is actually formed by using the above-described conventional method for manufacturing an optical waveguide, the surface of the substrate 4 and the torch 3 are caused by the inclination of the surface of the substrate 4, for example. If the distance between and differs depending on the distance from the center of the rotary table of the torch 3, etc.,
The film thickness of the optical waveguide film formed on the front surface side of the substrate 4 is different between the outer circumference 13 side and the inner circumference 14 side of the rotary table 6, and it is impossible to form a uniform optical waveguide film. There was a problem.

The present invention has been made in order to solve the above problems, and an object thereof is to make the distance between the substrate surface and the torch different between the outer peripheral side of the rotary table and the rotation center side due to the inclination of the substrate and the like. Even if it is, it is to provide a method of manufacturing an optical waveguide film capable of forming an optical waveguide film having a substantially uniform film thickness on the substrate surface.

[0013]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention places the substrate on a rotary table that performs rotary motion,
A torch for performing reciprocating linear movement on a radial line passing through the rotation center position of the rotation table independently of the rotation table is disposed on the front surface side of the substrate with a space from the substrate, and the torch is rotated from the rotation table rotation center position. The radial distance to the torch initial position is r ₀ , the initial moving speed of the torch is vb ₀ , and the radial distance from the rotary table rotation center position to the torch position at time t is r (t ), When the moving speed of the torch at time t is vb (t), v
Based on the control equation of b (t) = (r ₀ / r (t)) · vb ₀ , the moving speed vb (t) of the torch at time t is the diameter from the rotary table rotation center position of the torch at time t. While controlling so as to be inversely proportional to the distance r (t) in the line direction, the operation of ejecting the fine particles for forming a waveguide from the torch onto the surface of the substrate to form the unit fine particle layer is repeated a plurality of times to form the laminated fine particles. A method of manufacturing an optical waveguide film, comprising forming and then subjecting the laminated fine particle layer to heat treatment to form an optical waveguide film, wherein X = {vb ₀ · t / (r ₀ ±
vb ₀ · t)} ² as the torch moving speed vb (t)
From the control formula of the torch distance r (t) at the time t
Including constants a, b, c and d, r (t) = r ₀ · (1 ±
vb ₀ · t / r ₀ ) · (1-ax−bx ² −cx ³ −d
x ⁴ ) is polynomial expanded to each constant a,
b, c, and d are determined to determine the torch moving speed vb
The moving speed vb (t) of the torch is controlled by substituting it into the control equation (t).

Further, each constant a, b, c, d of the expansion formula
Corresponds to the distance between the substrate surface and the torch that changes depending on the inclination of the substrate surface. When the distance between the torch and the substrate surface becomes smaller as the torch approaches the rotation center position of the rotary table, at least one of the constants a and b. Either value is determined to be larger than the theoretical value. On the other hand, when the distance between the torch and the substrate surface increases as the torch approaches the rotation center position of the rotary table, at least one of the constants a and b is theoretically determined. It is also a characteristic configuration of the present invention to determine the value smaller than the value.

[0015]

In the present invention having the above-mentioned structure, X = {v is obtained from the control formula of the torch moving speed vb (t) shown in the above formula (1).
b ₀ · t / (r ₀ ± vb ₀ · t)} ² , the torch distance r (t) at the time t is a constant a,
It is polynomial expanded to the following equation (4) including b, c and d. In the term (r ₀ ± vb ₀ · t), when the torch moves from the inner circumference side to the outer circumference side of the rotary table, it is “+”, and conversely, it moves from the outer circumference side to the inner circumference side. In this case, it becomes "-". Further, the value of r ₀ also differs between the case where the torch moves from the inner circumference side to the outer circumference side and the opposite case.

R (t) = r ₀ · (1 ± vb ₀ · t / r ₀ ) · (1-ax−bx ² −cx ³ −dx ⁴ ) ... (4)

The constants a, b, c, and
d is determined, and the torch moving speed vb
Substituting into the control equation of (t), while controlling the moving speed of the torch based on the torch moving speed vb (t) after the substitution, fine particles for forming a waveguide are ejected from the torch onto the substrate surface to form a unit fine particle layer. Is formed. This operation is repeated a plurality of times to form the laminated fine particle layer, and then the laminated fine particle layer is heat-treated to form the optical waveguide film.

The constants a, b, c, and d correspond to the distance between the substrate surface and the torch that changes depending on the inclination of the substrate surface. As the torch approaches the center of rotation of the rotary table, the torch and the substrate surface. When the distance between the torches becomes smaller, the value of at least one of the constants a and b is determined to be larger than the theoretical value, while the distance between the torch and the substrate surface becomes larger as the torch approaches the rotation center position of the rotary table. At least one of the constants a and b is determined to be smaller than the theoretical value, and thus, the constants a, b, c, and d of the expansion equation are determined corresponding to the distance between the substrate surface and the torch. As a result, if the control equation of the moving speed of the torch is corrected, even if the distance between the substrate surface and the torch is significantly different between the outer peripheral side of the rotary table and the rotational center side. Even if, uniform optical waveguide film is formed on the substrate surface.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. The manufacturing method of the optical waveguide film of this embodiment is as shown in FIG.
The optical waveguide film is formed on the surface side of the substrate 4 by using the apparatus shown in FIG. 2. In the description of the present embodiment, the same reference numerals are given to the same names as those in the conventional example, and the duplicated description will be omitted. The method of manufacturing the optical waveguide film of the present embodiment is almost the same as the method of manufacturing the optical waveguide film of the conventional example, and the characteristic of the present embodiment different from the conventional example is that the moving speed vb of the torch 3 is
When controlling (t), X = {vb ₀ · t / (r ₀ ±
vb ₀ · t)} ² , the distance r (t) of the torch 3 at time t is obtained by polynomial expansion from the control formula of the torch moving speed vb (t), and the control formula of the torch moving speed vb (t) is obtained. That is, the moving speed vb (t) of the torch 3 is controlled by substitution.

As described above, the moving speed vb of the torch 3
Since the control equation of (t) is represented by the above equation (1), from the equation (1),

R (t) · (dr / dt) = r ₀ · vb ₀ (5)

It becomes When both sides of this equation (5) are integrated at time t, the following equation (6) is obtained. Therefore, the distance r (t) of the torch 3 at time t can be expressed by the following equation (7).

∫r (t) · (dr / dt) · dt = ∫ (r ₀ · vb ₀ ) · dt (6)

R (t) = √ (r ₀ ² ± 2 · r ₀ · vb ₀ · t) = r ₀ · (1 ± vb ₀ · t / r ₀ ) · √ [1- {vb ₀ · t / (R ₀ ± vb ₀ · t)} ² ] (7)

Here, X = {vb ₀ · t / (r ₀ ± vb
₀ · t)} ² and √ [1- {vb ₀ · t in Equation (7).
/ (R ₀ ± vb ₀ · t)} ² ] is polynomial expanded by the well-known Maclaurin expansion or Taylor expansion, the distance r (t) of the torch 3 at the time t is a constant a,
It is expanded to the following equation (8) including b, c, and d.

R (t) = r ₀ · (1 ± vb ₀ · t / r ₀ ) · (1-ax−bx ² −cx ³ −dx ⁴ ) ... (8)

When this equation is expanded according to the formula, the constants a, b, c and d are a = 1/2 and b, respectively.
= 1/8, c = 1/16, d = 15/384 (theoretical values).

In this embodiment, the constants (coefficients) a, b, c and d in the equation (8) are determined to the above theoretical values,
The distance r ₀ from the rotation center position of the rotary table 6 to the initial position of the torch 3 in the radial line R direction, the initial moving speed vb ₀ of the torch 3, and the initial rotation angular velocity ω ₀ of the rotary table 6 are used as parameters, and each parameter is represented. An optical waveguide film was prepared with the value shown in 1.

[0029]

[Table 1]

In the present embodiment, the vertical displacement of the rotary table 6 is ± 200 μm or less, and the variation in the distance between the surface of the substrate 4 and the torch 3 which varies depending on the inclination of the surface of the substrate 4 is ± 200 μm or less. Is.

FIG. 2 shows the flame 10 of the torch 3 when the moving speed vb (t) of the torch 3 is controlled by the parameters given in Table 1 by the method for manufacturing the optical waveguide film of this embodiment.
The results of examining the relationship between the position of and the film thickness of the optical waveguide film are shown. Even if the parameters shown in Table 1 are changed variously, the relationship between the position of the flame 10 of the torch 3 and the film thickness of the optical waveguide film becomes the relationship data as shown in FIG.
It was confirmed that the film thickness variation depending on the position of the flame 10 was ± 1% or less.

As is apparent from this figure, when the variation of the distance between the surface of the substrate 4 and the torch 3 is ± 200 μm or less, the constants a, b, c, d in the expansion equation of the above equation (8) are calculated as described above. An optical waveguide film having a substantially uniform film thickness is formed by determining the theoretical value and substituting it in the above equation (1) which is a control expression of the torch moving speed vb (t) to control the moving speed of the torch 3. It was confirmed that it was possible.

Next, a second embodiment of the method of manufacturing an optical waveguide film according to the present invention will be described. This embodiment is different from the first embodiment in that the constants a, b, c and d of the expansion equation shown in the equation (8) are changed according to the inclination of the surface of the substrate 4. When the distance between the torch 3 and the surface of the substrate 4 becomes smaller as the torch 3 gets closer to the position of the center of rotation C of the rotary table 6, at least one of constants a and b is made to correspond to the distance between the surface of No. 4 and the torch 3. One of the values is determined to be larger than the theoretical value, while the torch 3 approaches the position of the rotation center C of the rotary table 6 as the torch 3 approaches.
When the distance between the substrate 4 and the surface of the substrate 4 becomes large, at least one of the constants a and b is determined to be smaller than the theoretical value.

Theoretically, if the constants (coefficients) a, b, c, and d in the equation (8) are determined to be theoretical values and the moving speed vb (t) of the torch 3 is controlled, the torch 3 When the distance between the torch 3 and the surface of the substrate 4 becomes smaller as the position of the rotary table 6 becomes closer to the position of the rotation center C, that is, the height of the rotary table 6 on the inner circumference 14 side is higher than that on the outer circumference 13 side. In the case of the rotation, the rotary table 6 out of the surface of the substrate 4
The laminated fine particle layer forming the optical waveguide film is deposited thicker on the inner circumference 14 side. On the contrary,
When the distance between the torch 3 and the surface of the substrate 4 increases as the torch 3 approaches the position of the rotation center C of the rotary table 6, that is, the height of the rotary table 6 on the outer circumference 13 side rather than the inner circumference 14 side. 2 is higher, the laminated fine particle layer is deposited thicker on the outer peripheral side, and the thickness of the optical waveguide film becomes thicker on the outer peripheral side 13 of the turntable 6 on the surface of the substrate 4.

In the present embodiment, in consideration of the above, first,
The state of the film thickness distribution of the optical waveguide film when each coefficient a, b, c, d of the formula (8) was changed was simulated and investigated. As a result, when each coefficient is increased, the optical waveguide film is deposited thicker on the surface side of the substrate 4 located on the outer circumference 13 side of the turntable 6 than on the surface of the substrate 4 located on the inner circumference 14 side of the turntable 6, On the contrary, when each coefficient is determined to be small, the surface of the substrate 4 located on the inner circumference 14 side of the turntable 6 has a thicker optical waveguide film than the surface of the substrate 4 located on the outer circumference 13 side of the turntable 6. It was confirmed that deposits were formed. It was also confirmed that when the third- and fourth-order coefficients c and d were changed, there was almost no change in the film thickness distribution of the optical waveguide film.

FIGS. 3 and 4 show, as an example of the above simulation results, an optical waveguide when the first-order coefficient a and the second-order coefficient b of the equation (8) are changed as shown in Table 2. The results of the film thickness variation investigation are shown.

[0037]

[Table 2]

FIG. 3A shows the flame position of the torch 3 and the film thickness of the optical waveguide film when the first-order coefficient a is determined to be larger than the theoretical value under the condition of condition 1 in Table 2. The relationship with the distribution is shown in (b) of the same figure, under the condition of condition 2 in Table 2, the flame position of the torch 3 and the optical waveguide film when the coefficient a is determined to be smaller than the theoretical value. The relationship with the film thickness distribution is shown. Further, FIG. 4A shows the flame position of the torch 3 and the film thickness distribution of the optical waveguide film when the second-order coefficient b is determined to be larger than the theoretical value under the condition 3 of Table 2. The relationship is shown in (b) of the figure and the flame position of the torch 3 and the film thickness distribution of the optical waveguide film when the coefficient b is determined to be smaller than the theoretical value under the condition of condition 4 in Table 2. The relationship is shown.

As is clear from these results, when at least one of the coefficients a and b is determined to be larger than the theoretical value, the film thickness of the optical waveguide film deposited and formed on the substrate 4 is the same as that of the rotary table 6. The outer circumference 13 side is deposited thicker than the inner circumference 14 side, and conversely, if at least one of the coefficients a and b is determined to be smaller than the theoretical value, the inner circumference 14 side of the rotary table 6 is It is deposited thicker than the outer circumference 13 side. Further, the film thickness variation greatly changes when the first-order coefficient a is changed, and is not as remarkable when the second-order coefficient b is changed as when the coefficient a is changed, but the film-thickness distribution changes. It was confirmed.

In the present embodiment, based on these results, first, as a first specific example of the present embodiment, in a state where the height of the inner circumference 14 side of the rotary table 6 is 1000 μm higher than the height of the outer circumference 13 side. The respective coefficients of the equation (8) were determined as shown in Condition 3 of Table 2 to form the optical waveguide film. As a result, as shown in FIG. 5A, even if the position of the flame 10 of the torch 3 changes, the film thickness of the optical waveguide film deposited and formed on the surface side of the substrate 4 hardly changes, and the film thickness variation It was possible to form a uniform optical waveguide film of ± 1%. In addition, in FIG. 9B, the flame 10 of the torch 3 when the moving speed vb (t) of the torch 3 is controlled by setting the respective coefficients a to d of the equation (8) to theoretical values. The measurement result of the film thickness distribution of the optical waveguide film with respect to the position is shown.

As described above, when the coefficients of the equation (8) are determined to be theoretical values and the moving speed of the torch 3 is controlled, the surface of the substrate 4 is tilted due to the tilt of the rotary table 6, whereby the substrate 4 is tilted. When the distance between the surface of No. 4 and the flame 10 of the torch 3 changes greatly, it is difficult to form an optical waveguide film having a uniform thickness, but it is possible to cope with the change in the distance between the surface of the substrate 4 and the torch 3. By correcting each coefficient of the equation (8) by doing so, an optical waveguide film having a uniform film thickness can be formed on the surface of the substrate 4.

As a second specific example of the present embodiment, the condition 4 in Table 2 is shown in which the height of the outer circumference 13 side of the rotary table 6 is 1000 μm higher than the height of the inner circumference 14 side. As described above, the respective coefficients of the equation (8) are determined and substituted into the control equation of the moving speed vb (t) of the torch 3 shown in the above (1) to control the moving speed of the torch 3. Similar to the first specific example described above, the film thickness distribution of No. 2 became a film thickness distribution as shown in FIG. 5A, and a uniform optical waveguide film having a film thickness variation of ± 1% was formed.

According to this embodiment, as described above, the substrate 4
The surface of the substrate 4 and the torch 3 that change depending on the inclination of the surface
Corresponding to the interval between and, each constant (each coefficient) a, of the polynomial expansion formula (8) of the distance r (t) of the torch 3 at time t,
Among the b, c, and d, at least one of the first-order coefficient a and the second-order coefficient b is determined to be larger or smaller than the theoretical value to perform correction so that the substrate 4 Even if the distance between the surface of the torch 3 and the torch 3 changes, a uniform optical waveguide film can be formed.

The present invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted. For example, in the first embodiment, the distance r of the torch 3 at time t
Each coefficient of the polynomial expansion equation (8) of (t) is determined as a theoretical value, and in the second embodiment, conditions 1 to 4 of Table 2 are determined to control the moving speed vb (t) of the torch 3. Although the values are substituted into the equation (1), the specific values of the respective coefficients a, b, c, d are not particularly limited and may be set appropriately.
For example, when the variation in the distance between the surface of the substrate 4 and the torch 3 is small, the coefficients a to d are determined to be theoretical values, and when the variation in the distance between the surface of the substrate 4 and the torch 3 is large, the variation in the distance is dealt with. At least one of the coefficients a and b may be changed to perform correction adjustment so that the film thickness of the optical waveguide film becomes uniform.

In the above embodiment, the moving speed control of the torch 3 when the distance between the surface of the substrate 4 and the torch 3 fluctuates according to the inclination of the rotary table 6 has been described. Due to the inclination of the soaking plate 8 or the like, the substrate 4
Even when the distance between the surface of the torch 3 and the torch 3 fluctuates, the moving speed of the torch 3 can be controlled by appropriately setting the coefficients a, b, c, and d in the same manner as in the above embodiment.

Further, in the above embodiment, the rotary table 6
1 is rotated in the A direction in FIG. 1, but the rotation direction of the rotary table 6 may be opposite to the A direction (counterclockwise).

Further, in the above embodiment, the plurality of substrates 4 are arranged in one row along the circumference of the rotary table 6, but the substrates 4 are arranged on the rotary table as shown by the broken line portion 16 in FIG. 1, for example. The optical waveguide film may be formed by arranging a plurality of rows along the circumference of the.

[0048]

According to the present invention, the moving speed vb (t) of the torch, which reciprocates linearly independently of the rotary table, has a radial distance r (from the rotary table rotation center position of the torch at time t. From the control equation of the torch moving speed that is controlled so as to be inversely proportional to t), the torch distance r (t) at time t is polynomial expanded into an equation including constants a, b, c, d, and each constant a, b, It is possible to easily control the moving speed of the torch by determining c and d and substituting them into the control equation of the torch moving speed vb (t).

When the constants a, b, c, d of the expansion equation are determined, the torch corresponds to the distance between the substrate surface and the torch, which changes depending on the inclination of the substrate surface, and the torch corresponds to the rotation center position of the rotary table. When the distance between the torch and the substrate surface becomes smaller as it approaches, the value of at least one of the constants a and b is determined to be larger, while as the torch approaches the rotation center position of the rotary table, the torch and the substrate surface are separated. When the distance becomes large, at least one of the constants a and b is determined to be small and each constant in the polynomial expansion formula is corrected, and even if the distance between the substrate surface and the torch changes, the change will not occur. It can be applied to form a uniform optical waveguide film.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a main configuration of an apparatus for depositing and forming an optical waveguide film on a surface of a substrate.

FIG. 2 is a graph showing the relationship between the flame position of the torch and the film thickness distribution of the optical waveguide film in the first embodiment of the method of manufacturing an optical waveguide film according to the present invention.

FIG. 3 shows a simulation result of the relationship between the flame position of the torch and the film thickness of the optical waveguide film when the first-order coefficient a of the polynomial expansion equation used in the method for manufacturing an optical waveguide film according to the present invention is changed. It is a graph.

FIG. 4 shows a simulation result of the relationship between the flame position of the torch and the film thickness distribution of the optical waveguide film when the quadratic coefficient b of the polynomial expansion formula used in the method for manufacturing an optical waveguide film according to the present invention is changed. It is a graph shown.

FIG. 5 is a graph showing the relationship between the flame position of the torch and the film thickness distribution of the optical waveguide film in the second embodiment of the optical waveguide film manufacturing method according to the present invention.

[Explanation of symbols]

 3 torch 4 substrate 6 rotary table 10 flame 13 outer circumference 14 inner circumference

Claims (2)

[Claims] 1. A torch which mounts a substrate on a rotary table which makes a rotary motion, and which reciprocates linearly independently of the rotary table on a radial line passing through a rotation center position of the rotary table. At a distance from the center of rotation of the rotary table to the initial position of the torch in the radial direction by r ₀ , and the initial moving speed of the torch is v.
b ₀ , the radial direction distance from the rotary table rotation center position to the torch position at time t is r (t),
When the moving speed of the torch at time t is vb (t), the moving speed vb of the torch at time t is calculated based on the control equation of vb (t) = (r ₀ / r (t)) · vb _0.
While controlling so that (t) is inversely proportional to the radial direction distance r (t) from the rotary table rotation center position of the torch at time t, the torch ejects fine particles for waveguide formation onto the substrate surface. A method for producing an optical waveguide film, comprising forming laminated fine particles by repeating an operation of forming a unit fine particle layer a plurality of times, and then subjecting the laminated fine particle layer to a heat treatment to form an optical waveguide film, X = {vb ₀ · t
/ (R ₀ ± vb ₀ · t)} ² from the control equation of the torch moving speed vb (t), the torch distance r (t) at the time t includes constants a, b, c, d, and r ( t) = r
₀ · (1 ± vb ₀ · t / r ₀ ) · (1-ax−bx ² −
cx ³ −dx ⁴ ) is polynomial expanded, and each constant a, b, c, d of this expanded expression is determined and substituted into the control expression of the torch moving speed vb (t). A method of manufacturing an optical waveguide film, which comprises controlling a moving speed vb (t). 2. The expansion constants a, b, c, and d correspond to the distance between the substrate surface and the torch, which changes depending on the inclination of the substrate surface, and the torch becomes closer to the center of rotation of the rotary table. When the distance between the torch and the substrate surface becomes smaller, at least one of the constants a and b is determined to be larger than the theoretical value. On the other hand, as the torch approaches the rotation center position of the rotary table, the distance between the torch and the substrate surface becomes smaller. The method for producing an optical waveguide film according to claim 1, wherein at least one of the constants a and b is determined to be smaller than a theoretical value when is larger.