JPH10186130A - Production of optical interference filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical interference filter having excellent optical characteristics and adhesion property and excellent durability with less change with lapse of time by specifying an ionization atmosphere at the time of depositing TiO2 by evaporation on a transport substrate. SOLUTION: The production of the optical interference filter 8 consisting of cyan 9 layers is executed by alternately laminating TiO2 thin films 3 and SiO2 thin films 4 on the substrate 2 having 0.5mm thickness to 9 layers by using an ion assisted vapor deposition device. Namely, the TiO2 of a pellet type is used as a high-refractive index material and the granular SiO2 is used as a low-refractive index material. The respective materials are heated and evaporated by irradiation with an electron beam to alternately deposit the transparent thin films by evaporation on the substrate 2. This optical interference filter 8 is formed as so-called λ/4 alternate multilayered films designed to in such a manner that the optical film thicknesses of the respective layers are 1/4 of the transmitted light wavelength (λ). At the time of forming the films of the TiO2 by vapor deposition, the ratio of the number of the ions in ionizing gases to the number of the TiO2 particles to be deposited on the substrate 2 by evaporation is specified to 6 to 8%, by which the temp. of the substrate 2 may be lowered to <=130 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical interference filter in which transparent thin films of TiO ₂ (titanium dioxide) and SiO ₂ (silicon dioxide) are alternately vapor-deposited a predetermined number of times on a transparent substrate. In particular, the present invention relates to a method for manufacturing an optical interference filter for forming a TiO ₂ film by vapor deposition using an ion-assisted vapor deposition method.

[0002]

2. Description of the Related Art Hitherto, as an optical filter (for example, a color filter or the like) used for a liquid crystal display device or a solid-state imaging device device, a material having a high refractive index (for example, TiO ₂ , ZrO ₂ , A transparent thin film made of ZnS or the like, and a material having a low refractive index (for example, SiO ₂ ,
A plurality of transparent thin films made of MgF _2, etc.
So-called optical interference filters are known. The light interference filter is configured to reflect or transmit light in a desired wavelength range by alternately stacking transparent thin films having different refractive indexes and utilizing light interference by the transparent thin films. When the optical interference filter is used as a transmission type optical filter, it has a low light absorption and a high light transmittance. Therefore, when the optical interference filter is used in a liquid crystal display device, a solid-state imaging device device, or the like, an image display with good contrast and the like can be obtained.

The light transmittance of the optical interference filter at each light wavelength is determined by the optical thickness (the product of the refractive index of the thin film and the thickness of the thin film) of the transparent thin films alternately laminated.
The refractive index, the film thickness, and the number of layers of the transparent thin film to be laminated are appropriately set so that light in a desired wavelength range is transmitted. In general, the optical film thickness is set so as to be ４ of the wavelength (λ) of the transmitted light.

In manufacturing an optical interference filter, since a transparent thin film formed on a transparent substrate has a small thickness, a so-called physical vapor deposition method such as a vacuum vapor deposition method or a sputter vapor deposition method (PV) is used.
D method) is generally used. TiO ₂ (titanium dioxide) is used as a material having a high refractive index,
SiO ₂ (silicon dioxide) is commonly used as a material having a low refractive index.

Further, as a modification of the physical vapor deposition method (PVD method), a so-called ion-assisted vapor deposition method for performing vapor deposition on a transparent substrate while supplying an ionized gas is known. When the vaporized vapor deposition material is coagulated and vapor-deposited on a substrate in an ionized gas atmosphere using an ion-assisted vapor deposition method, the crystallization of the vapor-deposited material is promoted by the ions, and the adhesion and moisture resistance are improved. This improves the film characteristics such as. Also, because the refractive index of the deposited material increases,
In particular, it can be said that it is effective to use the ion-assisted deposition method when depositing a high refractive index material. If necessary, after the deposition of the material is completed, a method of heating the substrate for a predetermined time to promote crystallization of the deposited material and improve the film characteristics of the material (so-called annealing treatment) is performed. In some cases.

FIG. 1 is a view schematically showing a structural example of an ion-assisted vapor deposition apparatus 1 having an ion gun 7. TiO _{2 in the} form of pellets or granules placed in the vapor deposition device 1
Each of SiO ₂ and SiO ₂ is irradiated with an electron beam 6 by an electron beam irradiation device, and is heated and vaporized. The shutters 5 can be opened and closed with each other as appropriate.
During the deposition of ₂ to the transparent substrate 2, in which the shutter 5a open, the shutter 5b is closed. Conversely, when depositing SiO _{2 on} the transparent substrate 2, the shutter 5a is closed and the shutter 5b is opened. As a result, TiO ₂ and SiO ₂ thin films are alternately stacked and deposited on the transparent substrate 2. In FIG. 1, one transparent substrate 2 is mounted on the umbrella-shaped lens dome, but a plurality of transparent substrates 2 are actually mounted on the lens dome.

Next, oxygen (O_Two) And argon (A
r) is supplied to the ion gun 7 (for example, Kauf
(Man-type ion gun)
Supplied. In addition, oxide deposition can be performed in an oxidizing atmosphere.
For example, since deposition on the transparent substrate 2 is promoted, Ti
O_TwoOxygen gas from the gas inlet
(O _Two) Is supplied into the vapor deposition apparatus 1. In addition,
The inside of the vapor deposition apparatus 1 is sequentially exhausted from the exhaust port.
is there.

[0008]

Conventionally, when an optical interference filter is manufactured by using a vapor deposition apparatus as shown in the above-described example, the transparent substrate 2 placed in the vapor deposition apparatus 1 is heated. Things. In particular, high refractive index material Ti
During the deposition of O ₂ , the temperature of the transparent substrate 2 is set to, for example, 200 to 30.
This was a high temperature of about 0 ° C. That is, when the temperature of the transparent substrate 2 is low, when TiO ₂ is deposited on the substrate 2, the deposited TiO ₂ is in an amorphous state, and a desired high refractive index cannot be obtained. ,
It becomes a light absorbing film. This is because when the substrate temperature is high, crystallization of the deposited TiO ₂ proceeds, and a desired high refractive index can be obtained. If TiO ₂ has a low refractive index, desired spectral characteristics cannot be obtained, and if it is a light absorbing film, it can be said that light transmittance decreases.

FIG. 6 shows the relationship between the substrate temperature (° C.) when vaporized TiO ₂ is deposited and the refractive index (n) at a wavelength of 600 nm of the deposited TiO ₂ . As shown in FIG. 6, when the substrate temperature is lower than, for example, 130 ° C., the TiO ₂ becomes an amorphous state and has a low refractive index. When the substrate temperature is as high as 200 to 300 ° C., the TiO ₂ becomes a crystalline state and when the refractive index becomes high. I can say.

Further, by using the above-mentioned ion assisted vapor deposition method, it is possible to obtain a Ti film having a desired refractive index at a low substrate temperature.
It can be said that it is possible to obtain an O ₂ thin film. However, in this case, the adhesion of the TiO ₂ thin film to the substrate 2 is reduced. Further, the moisture resistance of the deposited TiO ₂ thin film deteriorates, and the TiO ₂ thin film absorbs surrounding moisture over time,
This causes a problem that the refractive index and the film thickness change, and as a result, the optical characteristics such as the light transmittance and the spectral characteristics of the optical interference filter change with time. The thin film of SiO ₂ , which is a low-refractive material, has a low substrate temperature dependency at the time of vapor deposition on the substrate 2.
It can be said that the rate of change with time of the iO ₂ thin film is practically negligible.

For the above reasons, the temperature of the transparent substrate 2 is set to a high temperature of about 200 to 300 ° C. during the deposition of TiO _2. Therefore, the transparent substrate 2 has heat resistance such as glass. It can be said that materials must be used.

In recent years, an optical interference filter has been incorporated.
There is a demand for weight reduction of a liquid crystal display device or a solid-state imaging device device, and the weight of the transparent substrate 2 needs to be reduced. To do that,
As a material for the transparent substrate 2, a lightweight plastic material such as PET (polyethylene terephthalate) is suitable.

However, when a plastic material is used as the material of the transparent substrate 2, for example, the plastic material has poor heat resistance, and the substrate 2 is deformed due to heating of the substrate when TiO ₂ is deposited by a vapor deposition method. It can be said that.

When the heating temperature of the substrate 2 is lowered to prevent the deformation of the substrate having no heat resistance, as described above, the optical characteristics of the optical interference filter are deteriorated, and the adhesion, moisture resistance, etc. Had to be less durable.

The present invention has been made in view of the above circumstances. Even when a light interference filter is manufactured by an ion-assisted vapor deposition method using a transparent substrate having low heat resistance, the present invention has excellent optical characteristics and adhesion, and It is another object of the present invention to provide a method of manufacturing an optical interference filter capable of obtaining an optical interference filter having a small change with time and having excellent durability.

[0016]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies, and as a result, focused on the ionization atmosphere when TiO ₂ was deposited on a transparent substrate. Things.

As described in the above section (prior art), when TiO ₂ is deposited, an ionized gas (hereinafter, referred to as an ionized gas) is used.
When the vapor deposition material is coherently vapor-deposited on the substrate 2 under an atmosphere of (ionized gas), the crystallization of the vapor-deposited material is promoted by the ions. For this reason, the present inventors should find a suitable ratio between the number of TiO ₂ particles deposited on the transparent substrate 2 and the number of ions in the ionized gas, that is, the number of ions in the ionized gas reaching the transparent substrate 2. Considering that the crystallization of TiO _{2 at} the time of vapor deposition is further advanced and that the substrate temperature at the time of vapor deposition is low, a TiO ₂ thin film having excellent film properties such as adhesion, durability, and optical properties can be obtained. It is the invention.

Here, the present inventors have calculated the ratio of the number of TiO ₂ particles deposited on the transparent substrate 2 to the number of ions in the ionized gas reaching the transparent substrate 2 by the following equation (Equation 1). As shown, the ion ratio (%) is set.

[0019]

(Equation 1)

The term (number of vapor-deposited particles) in the above (Equation 1) indicates the number of TiO ₂ particles vapor-deposited on the transparent substrate, and is calculated by the following equation (Equation 2). The (deposition rate) in (Equation ₂ ) indicates the rate of increase in the thickness of the TiO ₂ thin film deposited on the substrate per second (Å / sec). Also,
In (Equation 2), (density of vapor-deposited particles) indicates the density (g / cm ³ ) of the TiO ₂ thin film vapor-deposited on the transparent substrate, and (molecular weight of vapor-deposited particles) indicates the density of TiO ₂ vapor-deposited on the transparent substrate. It indicates the molecular weight, which is 3.84 g / cm ³ , 79.8
This is a constant value of 8.

[0021]

(Equation 2)

From the equation (2), if the rate of increase in the thickness of the deposited TiO ₂ thin film per second (分 か る / sec) is measured, it can be said that the number of TiO ₂ particles deposited on the transparent substrate can be determined. .

Next, (number of ions) in (expression 1) indicates the number of ions reaching the transparent substrate, and is calculated by the following expression (expression 3).

[0024]

(Equation 3)

In the above (Equation 3), the term (ion current density) means the ion current (μ) flowing per unit area (cm ² ).
A) is shown.

That is, (ion ratio) is obtained by calculating (deposition rate) and (ion current density) during ion-assisted deposition.
By controlling, it can be said that it can be changed.

The present inventors have proposed a method of depositing TiO on a transparent substrate.
The ratio of the number of ions in the ionized gas reaching the transparent substrate to the number of the _two particles, that is, the ion ratio was changed, and TiO ₂ was actually deposited on the substrate. In addition, various values are also used for the ratio of oxygen and argon in the ionized gas, the output of the ion gun used for ionizing oxygen and argon, the partial pressure of the oxygen gas supplied separately, and the deposition rate of TiO _{2 on} the transparent substrate. , TiO ₂ was actually deposited on the substrate. As a result, the present invention has been made based on empirical and examples described below.

That is, in order to achieve the above object in the present invention, first, in claim 1, TiO ₂ and SiO ₂ heated and vaporized by an electron beam heating method are alternately provided on a transparent substrate a predetermined number of times. At least TiO ₂ is deposited on a heated transparent substrate in an atmosphere of an ionized gas composed of oxygen and argon and an oxygen gas supplied separately from the ionized gas. in the method for manufacturing an optical interference filter using an evaporation method, when the TiO ₂ deposition film, for TiO ₂ number of particles to be deposited on the transparent substrate, by 6 to 8 percent ratio of the number of ions of the ionized gas 130 ℃ transparent substrate temperature
A method of manufacturing an optical interference filter characterized by the following.

According to a second aspect of the present invention, there is provided the method of manufacturing an optical interference filter according to the first aspect, wherein the ratio of oxygen to argon in the ionized gas is set to 1: 9. Furthermore, in claim 3,
The output of the ion gun used for ionizing oxygen and argon is 5
00 ± 50 eV, gas partial pressure of oxygen gas supplied separately is 3 × 10
And ^-2 Pa, further was the method of manufacturing an optical interference filter according to claim 1 or 2, characterized in that the deposition rate of the transparent substrate of TiO ₂ than 2.0 Å / sec or more 2.5 Å / sec Things.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method for manufacturing an optical interference filter according to the present invention will be described based on the following (Examples), and further description will be continued.

(Example 1) As shown in FIG. 7, a TiO ₂ thin film 3 and a SiO ₂ thin film 4 were alternately formed using a 0.5 mm thick PET by using the ion assisted vapor deposition apparatus 1 shown in FIG.
A nine-layer cyan light interference filter 8 having nine layers laminated on the substrate 2 was manufactured. That is, pellet type TiO ₂ is used as the high refractive index material, and granular S ₂ is used as the low refractive index material.
Each material is heated and vaporized by electron beam irradiation using iO ₂ , and a transparent thin film is alternately deposited on the substrate 2. The optical interference filter 8 is a so-called λ / 4 alternating multilayer film in which the optical thickness of each layer is set to 透過 of the transmitted light wavelength (λ).

In depositing TiO ₂ and SiO ₂ , ion-assisted deposition is performed. Oxygen and argon were ionized by a Kaufman-type ion gun 7 (model name "KIS-80D") using an ionized gas in which the ratio of oxygen to argon was 1: 9. Furthermore, TiO
At the time of vapor deposition of ₂ , oxygen gas was supplied into the vapor deposition apparatus 1 from a gas inlet separately from the ionized gas.

The following Table 1 shows the manufacturing conditions at this time.

[0034]

[Table 1]

(Backfill gas) in Table 1
Indicates the partial pressure of the oxygen gas supplied from the gas inlet during the deposition of TiO ₂ , and the gas flow rate of the oxygen gas is 90 SCCM.
And The (ion current density) at this time was 8 μA / cm ^{2 as} a result of actual measurement.

Under the above conditions (Table 1), the (ion ratio) obtained from the above (Equation 1) was 7.5%. Thereby, the TiO ₂ thin film has a refractive index (n) = 2.
3052, film thickness (d) = 84.42 °, optical film thickness (nxd) =
It was 194.60. FIG. 5 shows the spectral characteristics of the obtained optical interference filter, that is, the spectral transmittance.
It can be said that the spectral characteristics are excellent in practical use.

Next, in order to examine the moisture resistance of the optical interference filter 8 obtained in (Example 1), the humidity was 98%, the temperature was 60 ° C.
After the light interference filter 8 was left in the atmosphere described above, a moisture resistance test was performed to measure the change in the light wavelength at which the transmittance became 50%. As a result, the light wavelength immediately after manufacturing was 560.5 nm, and the light wavelength after being left in the above atmosphere for 15 days was 565.0 nm.
The light wavelength obtained after standing for 30 days in the above atmosphere was 564.5 nm. It can be said that this change with the passage of time has no practical problem.

(Example 2) A PET substrate having a substrate temperature of 23 ° C and a thickness of 0.5 mm under the same conditions as in the above (Example 1) except that the (deposition rate) of TiO ₂ was set to 2.5 ° / sec. A TiO ₂ thin film was deposited thereon such that the optical film thickness was ４ of the transmitted light wavelength (λ). That is, in (Example 2), the (ion ratio) was set to 6.9%. As a result, the refractive index (n) = 2.3167 and the film thickness (d) = 8
A TiO ₂ thin film having a thickness of 6.06 ° and an optical film thickness (nxd) of 199.37 was obtained.

(Comparative Example 1) A PET substrate having a substrate temperature of 23 ° C. and a thickness of 0.5 mm under the same conditions as in the above (Example 1) except that the (deposition rate) of TiO ₂ was 0.9 ° / sec. On top, T is adjusted so that the optical film thickness is １ ／ of the transmitted light wavelength λ.
An iO ₂ thin film was deposited. That is, in (Comparative Example 1), the (ion ratio) was set to 19.2%. As a result, the refractive index (n) = 2.2528 and the film thickness (d) = 6
A TiO ₂ thin film having a thickness of 3.11 ° and an optical thickness (nxd) of 142.17 was obtained.

(Comparative Example 2) A PET substrate having a substrate temperature of 23 ° C. and a thickness of 0.5 mm under the same conditions as in the above (Example 1) except that the (deposition rate) of TiO ₂ was 1.5 ° / sec. On top, TiO ₂ is deposited so that the film thickness becomes に な る of the transmitted light wavelength λ.
A thin film was deposited. That is, in (Comparative Example 2),
(Ion ratio) was 11.5%. As a result, the refractive index (n) = 2.2650, the film thickness (d) = 90.08 °,
A TiO ₂ thin film having an optical thickness (nxd) = 204.03 was obtained.

Comparative Example 3 TiO_Two(Deposition rate)
Same as above (Example 1) except that 1.8 ° / sec.
Under the conditions of above, the substrate temperature is 23 ℃, on a 0.5mm thick PET substrate
TiO 2 so that the film thickness becomes １ ／ of the transmitted light wavelength λ._Two
A thin film was deposited. That is, in (Comparative Example 3),
(Ion ratio) was 9.6%. The result
As a result, refractive index (n) = 2.2770, film thickness (d) = 87.18 °, light
TiO with a chemical film thickness (nxd) = 198.50 _TwoA thin film was obtained.

Comparative Example 4 TiO_Two(Deposition rate)
Same as the above (Example 1) except that it was 2.0 ° / sec.
Under the conditions of above, the substrate temperature is 23 ℃, on a 0.5mm thick PET substrate
TiO 2 so that the film thickness becomes １ ／ of the transmitted light wavelength λ._Two
A thin film was deposited. That is, in (Comparative Example 4),
(Ion ratio) was 8.8%. The result
As a result, refractive index (n) = 2.2914, film thickness (d) = 85.13Å, light
TiO with a chemical film thickness (n × d) = 195.07 _TwoA thin film was obtained.

The above (Example 1), (Example 2) and
(Comparative Example 1) ~ TiO ₂ thin film obtained by the Comparative Example 4, i.e., a graph showing a change in the refractive index of the TiO ₂ thin films obtained by changing the (ion ratio) is 2. In FIG. 2, the horizontal axis represents the ionic ratio when the TiO ₂ thin film was deposited.
And the vertical axis indicates the refractive index (n) of the TiO ₂ thin film.

As shown in FIG. 2, the output of the electron gun 7 for ionizing oxygen and argon (hereinafter referred to as ion assist output) is set to 500 eV, and (ion ratio)
Is 6 to 8%, the refractive index (n) of the TiO ₂ thin film
Can be said to be 2.3 or more, and it can be said that a preferable high refractive index is obtained in obtaining an optical interference filter.

For reference, the graph showing the relationship between the ion ratio and the refractive index of the TiO ₂ thin film obtained by changing the ion ratio while setting the ion assist output to 300 eV and 750 eV is also shown in FIG. ing. As can be seen from FIG. 2, at an ion assist output of 750 eV, the refractive index is as low as less than 2.3, and a favorable high refractive index is not obtained. When the refractive index is low, the number of laminated transparent thin films must be increased in order to obtain the desired spectral characteristics, and the cost and the manufacturing time are increased, which is not desirable.

At an ion assist output of 300 eV, a high refractive index is obtained when the ion ratio is increased. However, at an ion assist output of 300 eV, the allowable range of the deposition rate is small, and it is difficult to control the deposition rate. However, this is not a preferable output value in manufacturing the optical interference filter.

Next, as a moisture resistance test of the TiO ₂ thin film, (Example 1), (Example 2) and (Comparative Example 1)
-The TiO ₂ thin film obtained in (Comparative Example 4) was
It was left in an atmosphere at a temperature of 60 ° C. for 30 days. After a while, each T
The refractive index (n ′) and the film thickness (d ′) of the iO ₂ thin film were measured,
The optical film thickness (n ′ × d ′) was obtained.

FIG. 3 shows the change (%) in the optical film thickness before and after the moisture resistance test. In FIG. 3, the horizontal axis is TiO.
₂ shows the (ion ratio) during vapor deposition, and the vertical axis shows the change (%) in the optical film thickness. The variation (%) of the optical film thickness is obtained by the following equation (4).

[0049]

(Equation 4)

FIG. 4 is a graph showing the relationship between the change in the refractive index, the film thickness, and the optical film thickness before and after the above-mentioned moisture resistance test and the deposition rate. /
Second) and the vertical axis represents the amount of change (%). The changes in the refractive index and the film thickness are determined by the following (Equation 5) and (Equation 6), similarly to the above (Equation 4).

[0051]

(Equation 5)

[0052]

(Equation 6)

As shown in FIGS. 3 and 4, (ion ratio) is 6 to 8%, and (deposition rate) is 2.0 ° / sec to 2.5 °.
/ S, the variation of the optical film thickness is within ± 0.8%, and it can be said that such variation in practical use is within a range without any problem.

For reference, the ion assist output was set to 300 eV and 750 eV, and the amount of change in the optical film thickness after the same moisture resistance test was performed on the TiO ₂ thin film obtained by changing the ion ratio. It is also shown in FIG. As can be seen in FIG. 3, the ion assist output 750e
At V, it can be said that the change amount is small and relatively stable. However, as described above with reference to FIG. 2, the ion assist output 750 eV has a low refractive index and is not a desirable ion assist output.

At the ion assist output of 300 eV, there is a range in which the variation of the optical film thickness is within ± 0.8%, but as described above, the ion assist output is 300 eV.
Then, it can be said that it is difficult to control the deposition rate, which is not a preferable output value.

The embodiments of the present invention are not limited to the above description and drawings, and it goes without saying that various modifications are possible based on the spirit of the present invention.

For example, in the above embodiment, the substrate 2 is
Although an ET substrate is used, it can be said that other materials having poor heat resistance may be used, and a glass substrate may be used as in the related art.
Further, if the substrate has heat resistance, an annealing treatment may be performed after the vapor deposition.

[0058]

According to the method of manufacturing an optical interference filter of the present invention, it is possible to deposit a vapor deposition material on a substrate without raising the temperature of the substrate. Moreover, the obtained optical interference filter has excellent optical properties,
Good durability such as moisture resistance is obtained.

As a result, the selection range of the substrate material is widened, and it can be said that an optical interference filter can be formed even with a heat-resistant material such as a plastic material.

That is, for example, if a plastic material is used as the substrate material, it can be said that an optical interference filter which is lightweight and excellent in processability can be obtained, and the present invention is practically excellent.

[0061]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating an example of an ion-assisted vapor deposition apparatus.

FIG. 2 shows the results when TiO in the case where the ion ratio is changed.
FIG. 6 is a graph showing an example of a change in the refractive index of _two thin films.

FIG. 3 shows a TiO ₂ thin film obtained by changing the ion ratio,
FIG. 6 is a graph showing an example of a change in optical film thickness before and after a moisture resistance test.

FIG. 4 is a graph showing an example of changes in the refractive index, the film thickness, and the optical film thickness of the TiO ₂ thin film before and after the moisture resistance test when the deposition rate is changed.

FIG. 5 is a graph showing an example of the spectral characteristics of the optical interference filter obtained by the present invention.

FIG. 6 is a graph showing an example of the relationship between the substrate temperature when TiO ₂ is deposited and the refractive index of the deposited TiO ₂ .

FIG. 7 is an explanatory diagram showing an example of an optical interference filter obtained by the present invention.

[Explanation of symbols]

1 deposition apparatus 2 substrate 3 TiO ₂ thin film 4 SiO ₂ film 5 Shutter 6 electron beam 7 ion gun 8 optical interference filter

Claims (3)

[Claims] 1. A electron beam heating method a predetermined number of times alternately heating vaporized the TiO ₂ and SiO ₂ on a transparent substrate by, and evaporating at least evaporating the TiO ₂ is ionized consisting of oxygen and argon gas, in an atmosphere of oxygen gas supplied separately from the ionized gas is performed in a heated transparent substrate, in the manufacturing method of an optical interference filter using an ion-assisted deposition, the TiO ₂ of the evaporating At this time, with respect to the number of TiO ₂ particles deposited on the transparent substrate,
A method for manufacturing an optical interference filter, wherein the temperature of the transparent substrate is set to 130 ° C. or lower by setting the ratio of the number of ions in the ionized gas to 6 to 8%. 2. The method for manufacturing an optical interference filter according to claim 1, wherein the ratio of oxygen to argon in said ionized gas is 1: 9. 3. The output of an ion gun used for ionizing oxygen and argon is 500 ± 50 eV, the partial pressure of oxygen gas supplied separately is 3 × 10 ⁻² Pa, and the deposition rate of TiO _{2 on} a transparent substrate. 3. The method for producing an optical interference filter according to claim 1 or 2, wherein the value is set to 2.0 ° / sec or more and 2.5 ° / sec or less.