JP2009139925A - Optical multilayer film filter, method for producing optical multilayer film filter and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multilayer film filter which reduces adhesion of dust, and allows adhering dust to be easily removed, and a production method of the same. <P>SOLUTION: The optical multilayer filter 10 is composed of an inorganic thin film 2 having a plurality of layers formed on a glass substrate 1. The inorganic thin film 2 has a TiO<SB>2</SB>layer and an SiO<SB>2</SB>layer laminated sequentially alternately on the surface of the glass substrate in such a manner that an outermost surface layer is an SiO<SB>2</SB>layer (2L30), and a fluorine-containing organosilicon compound film 5 is formed on the surface of the outermost surface layer of the inorganic thin film 2. The density of the SiO<SB>2</SB>layer of the outermost surface layer is 1.9 to 2.1 g/cm<SP>3</SP>. When the SiO<SB>2</SB>layer of the outermost surface layer of the inorganic thin film 2 is determined as a first layer, a TiO<SB>2</SB>layer having a density of 4.1 to 4.8 g/cm<SP>3</SP>is selectively formed in a second layer (2H30) and a fourth layer (2H29) below the SiO<SB>2</SB>layer of the first layer, and an SiO<SB>2</SB>layer having a density of 1.9 to 2.1 g/cm<SP>3</SP>is selectively formed in a third layer (2L29). These SiO<SB>2</SB>layer and TiO<SB>2</SB>layers are formed by a vacuum deposition method. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an optical multilayer filter, a method for manufacturing an optical multilayer filter, and an electronic device apparatus incorporating the optical multilayer filter.

As an optical multilayer filter, a half mirror, an IR cut filter, a low-pass filter, and the like are known, and these are frequently used in electronic equipment. This optical multilayer filter is composed of a substrate and an inorganic thin film formed on the substrate by vapor deposition or the like.
The inorganic thin film has a multilayer film structure in which a high refractive index film made of titanium oxide (TiO ₂ ) or the like and a low refractive index film made of silicon oxide (SiO ₂ ) or the like are alternately stacked. In general, a silicon oxide film functioning as a protective film is formed on the outermost surface layer of the inorganic thin film, so that the surface thereof is not conductive and is easily charged with static electricity. For this reason, dust is easily attracted to the surface of the optical multilayer filter, and this dust may adversely affect the optical characteristics of an electronic apparatus incorporating the optical multilayer filter.
As a countermeasure against static electricity on the surface of the substrate on which the inorganic thin film is formed, for example, an example in which a transparent conductive film such as ITO (Indium Tin Oxide) is provided on the outer surface of dust-proof glass is known (Patent Document 1). reference). The transparent conductive film can effectively remove static electricity charged on the surface of the transparent conductive film without impairing the transparency of the glass and having conductivity.

JP 20042333501 A

However, in an optical multilayer filter in which the optical properties of the film constituting the surface of the multilayer film are important, if a transparent conductive film as described in Patent Document 1 is provided on the surface, the optical characteristics of the optical multilayer filter itself are reduced. May change.
In the above structure, the surface static electricity can be suppressed to reduce the adhesion of dust due to static electricity. However, since the transparent conductive film has a large surface energy of the outermost layer, the dust once adhered is difficult to be detached. Therefore, the above structure is not sufficient as a structure that reduces the adhesion of dust and easily removes the adhered dust.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The optical multilayer filter according to this application example is an optical multilayer filter having an inorganic thin film composed of a plurality of layers on a substrate, and the inorganic thin film is composed of a low density forming portion and a high density forming portion, A fluorine-containing organosilicon compound film is formed on the surface of the inorganic thin film, and the low-density forming portion includes a top layer of the inorganic thin film or a plurality of layers including the top layer, a low-density titanium oxide layer or a low-density layer. Formed of at least one of a silicon oxide layer, and the high-density forming portion includes a silicon oxide layer having a higher density than the low-density silicon oxide and the low-density forming portion between the low-density forming portion and the substrate. It is formed by laminating a titanium oxide layer having a density higher than that of the titanium oxide layer, and the total film thickness of the low density forming portion is within 280 nm.

According to this configuration, the outermost layer of the inorganic thin film or the plurality of layers including the outermost layer is a low density formation portion formed from at least one of a low density titanium oxide layer and a low density silicon oxide layer. As a result, the insulating property of the outermost layer of the inorganic thin film or a plurality of layers including the outermost layer is lowered (conductivity is increased). Therefore, the charge existing on the surface due to static electricity or the like can move between the outermost layer or a plurality of layers including the outermost layer. By grounding this charge, it is difficult for the charge to accumulate on the outermost surface of the optical multilayer filter, and dust and the like due to static electricity are less likely to be attached. Furthermore, if the total film thickness of the low density formation part is within 280 nm, the surface dust-proof effect by the low density layer can be obtained.
On the other hand, the formation of the fluorine-containing organosilicon compound film on the surface of the outermost layer of the inorganic thin film reduces the surface energy, suppresses the adhesion of dust, and can easily remove the dust once adhered. . Furthermore, since the fluorine-containing organic silicon compound film to be formed is thin (<10 nm) and has a density lower than that of the inorganic material, it is easy to pass charges through the lower layer, and the spectral characteristics are not affected.
If the density of the outermost layer in the inorganic thin film is low, the surface area of the outermost layer increases (corresponding to the increase in microscopic unevenness), and the area to which the fluorine-containing organic silicon compound film adheres increases. Therefore, the adhesion of the fluorine-containing organosilicon compound film is improved and the durability is improved.
Conventionally, inorganic thin films composed of low-density layers are prone to wavelength shifts, etc., but the above-mentioned structure also forms a high-density formed layer in addition to the low-density formed layer, and has high optical quality due to high density. The low wavelength shift and low H required for an optical multilayer filter
Good characteristics such as AZE and dust resistance are compatible.

[Application Example 2]
In the optical multilayer filter according to the application example described above, the density of the low-density silicon oxide layer is 1
. 9 to 2.1 g / cm ³ , the density of the low-density titanium oxide layer is 4.1 to 4.8 g / cm ³ , and the outermost layer of the inorganic thin film is formed of the low-density silicon oxide layer, It is desirable that the number of layers of the low density forming portion is formed by selecting any one of two to four layers.

According to this configuration, the density of the low-density silicon oxide layer is 1.9 to 2.1 g / cm ³ , and the density of the low-density titanium oxide layer is 4.1 to 4.8 g / cm ³ , In the low density formation portion, when the layer constituting the outermost layer is the first layer, a low density titanium oxide layer or a low density silicon oxide layer is selectively formed in the second to fourth layers. By doing so, as described above, it is possible to obtain an optical multilayer filter in which dust or the like due to static electricity is difficult to adhere, and dust once attached can be easily removed.

[Application Example 3]
In the optical multilayer filter according to the application example described above, it is preferable that the substrate is a glass substrate or a quartz substrate.

According to this configuration, since the substrate is formed of a glass substrate, a dust filter glass for a video device such as a CCD (Charge Coupled Device) that is not easily dusted, and a desired filter function are integrally configured. An optical multilayer filter including a UV-IR cut filter and an IR cut filter function can be obtained. Further, since the substrate is made of a quartz substrate, for example, as an optical low-pass filter that is not easily dusted, and an optical low-pass filter including, for example, a UV-IR cut filter and an IR cut filter function, which are integrally configured with a desired filter function. A filter can be obtained. Furthermore, this application example can also be applied to the formation of an antireflection film.

[Application Example 4]
In the manufacturing method of the optical multilayer filter according to this application example, an optical multilayer filter having an inorganic thin film composed of a plurality of layers on a substrate, wherein a high-density titanium oxide layer and a high-density on the surface of the substrate A high-density formed portion is formed by laminating a silicon oxide layer, and then a titanium oxide layer having a lower density than the high-density titanium oxide layer or the high-density formed portion is formed on the surface of the high-density formed portion by a vacuum deposition method. A low density formation portion formed of at least one of a silicon oxide layer having a density lower than that of the silicon oxide layer having a low density is formed within a total film thickness of 280 nm, and fluorine is further formed on the surface of the outermost layer of the low density formation portion. A containing organosilicon compound film is formed.

According to this method for producing an optical multilayer filter, an inorganic thin film is formed by forming at least one of a low-density titanium oxide layer and a low-density silicon oxide layer on the surface of a high-density formation layer by vacuum deposition. A low density formation part which constitutes the outermost layer or a plurality of layers including the outermost layer can be obtained. As a result, the insulation of the outermost layer that originally exhibits high insulation or a plurality of layers including the outermost layer is lowered. Therefore, the charge existing on the surface due to static electricity or the like can move between the outermost layer or a plurality of layers including the outermost layer. By grounding this electric charge (ground), it becomes difficult for the electric charge to collect on the outermost surface of the optical multilayer filter, and an optical multilayer filter that is less likely to be dusted due to static electricity can be obtained. Furthermore, when the total film thickness of the low density forming portion is within 280 nm, the above-described effect can be obtained.
In addition, the formation of a fluorine-containing organosilicon compound film on the silicon oxide layer that forms the outermost layer of the inorganic thin film reduces the surface energy, suppresses the adhesion of dust, and easily removes dust that has once adhered. Will be able to. Since the formed fluorine-containing organic silicon compound film is thin (<10 nm) and has a lower density than inorganic materials, it is easy to pass charges through the lower layer and does not affect the spectral characteristics. In addition, when the density of the outermost silicon oxide layer in the inorganic thin film is low, the surface area of the silicon oxide layer increases (corresponding to an increase in microscopic unevenness).
The area to which the fluorine-containing organosilicon compound film adheres increases. Therefore, the adhesiveness of the fluorine-containing organosilicon compound film is improved, and an optical multilayer filter having improved durability can be obtained.

[Application Example 5]
In the manufacturing method of the optical multilayer filter according to the application example, the density of the low-density silicon oxide layer is 1.9 to 2.1 g / cm ³ , and the density of the low-density titanium oxide layer is 4.1 to 4 .8
and g / cm ^3, the low-density layer number of the forming portion, to form by selecting one of the two layers 4 layers is desirable.

According to this method for producing an optical multilayer filter, a titanium oxide layer and a silicon oxide layer constituting the low density forming portion are formed by using a vacuum evaporation method, whereby the density is 1.9 to 2.1 g.
/ Silicon oxide layer and density of the low density cm ³ can be obtained titanium oxide layer having a low density of 4.1～4.8G / cm ^3. Then, when the low-density forming portion has the layer constituting the outermost layer as the first layer, the low-density titanium oxide layer or the low-density silicon oxide layer is selectively formed in the first to fourth layers. As described above, it is difficult for dust and the like due to static electricity to adhere,
In addition, it is possible to obtain an optical multilayer filter that can easily remove dust once adhered.

[Application Example 6]
In the method for producing an optical multilayer filter according to the application example, a pressure when the low-density silicon oxide layer is formed by the vacuum deposition method is 5 × 10 ^{−4 to} 5 × 10 ⁻² Pa. The pressure when the low-density titanium oxide layer is formed by the vacuum deposition method is 1.4 × 10 ^−2.
It is desirable that it is ˜3 × 10 ⁻² Pa.

According to this method for manufacturing an optical multilayer filter, the density when the silicon oxide layer is formed by vacuum deposition is 5 × 10 ^{−4 to} 5 × 10 ⁻² Pa, so that the density is 1.9 to 2.1 g / cm
³ low-density silicon oxide layers can be obtained. Further, by setting the pressure when the titanium oxide layer is formed by vacuum deposition to 1.4 × 10 ^{−2 to} 3 × 10 ⁻² Pa, the density is 4.1 to 4.
A low density titanium oxide layer of 8 g / cm ³ can be obtained.

[Application Example 7]
In the electronic device according to this application example, the optical multilayer filter is composed of an inorganic thin film composed of a plurality of layers on a substrate and a fluorine-containing organosilicon compound film formed on the surface of the inorganic thin film. The low-density formation portion includes a top layer of the inorganic thin film or a plurality of layers including the top layer, a low-density titanium oxide layer or a low-density silicon oxide layer. The high-density formation portion is formed between the low-density formation portion and the substrate, and the high-density silicon oxide layer and the low-density titanium oxide layer are lower than the low-density silicon oxide. An optical multi-layer film filter formed by laminating a higher density titanium oxide layer and having a total film thickness of the low density forming portion within 280 nm is incorporated.

According to this electronic apparatus device, the optical multilayer film filter has an inorganic thin film composed of a plurality of layers on the substrate and a fluorine-containing organosilicon compound film formed on the surface of the inorganic thin film, and the low-density forming portion is an inorganic thin film. The outermost layer or a plurality of layers including the outermost layer is formed of at least one of a low-density titanium oxide layer and a low-density silicon oxide layer, and the high-density formed portion is between the low-density formed portion and the substrate. In addition, an optical multilayer film filter formed of at least one of a high-density silicon oxide layer and a high-density titanium oxide layer and having a total film thickness of the low-density formation portion of 280 nm or less is incorporated, and thus, due to static electricity Dust is difficult to stick. In addition, dust that has once adhered can be easily removed. For example, imaging devices such as digital still cameras and digital video cameras, camera-equipped mobile phones, camera-equipped personal computers (personal computers), etc. have reduced the effects of dust. It can be effectively used as an electronic device.

[Application Example 8]
In the electronic device according to the application example described above, the density of the low-density silicon oxide layer is 1.9 to
2.1 g / cm ^3, the density of the low density titanium oxide layer of the 4.1~4.8g / cm ^3, the number of layers of low-density forming unit, select one of the two layers 4 layers It is desirable to incorporate an optical multilayer filter formed in this way.

According to this electronic device, the density of the low-density silicon oxide layer is 1.9 to 2.1 g / cm ³ ,
The density of the low-density titanium oxide layer is 4.1 to 4.8 g / cm ³ , and the low-density formation portion has a low-density titanium oxide layer or a low density when the layer constituting the outermost layer is the first layer. 1 density silicon oxide layer
Since an optical multilayer filter selectively formed in the range from the fourth layer to the fourth layer is incorporated, dust caused by static electricity is difficult to adhere, and dust once attached can be easily removed, for example, It can be effectively used as an electronic apparatus device that suppresses the influence of dust, such as an imaging device such as a digital still camera and a digital video camera, a mobile phone with a camera, and a portable personal computer with a camera (personal computer).

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. The present embodiment is an optical multilayer filter (UV-IR cut filter) that passes through the visible wavelength range and has good reflection characteristics in an ultraviolet wavelength range of a predetermined wavelength or less and an infrared wavelength range of a predetermined wavelength or more. It is an applied example.

(Configuration of optical multilayer filter)
FIG. 1 is a cross-sectional view schematically showing the configuration of the optical multilayer filter according to the present embodiment.
The optical multilayer filter 10 includes a glass substrate 1 as a substrate for transmitting light, a multilayer inorganic thin film 2 and a fluorine-containing organic silicon compound film 5.

The material of the inorganic thin film 2 is such that a high refractive index layer (H) made of a high refractive material is used as a titanium oxide layer.
An iO ₂ layer (n = 2.40) and a low refractive index layer (L) made of a low refractive material are composed of a SiO ₂ layer (n = 1.46) as a silicon oxide layer.
The inorganic thin film 2, from the glass substrate 1 side, TiO ₂ layer 2H1 of the high-refractive-index material is first laminated on the upper surface of the TiO ₂ layer 2H1 of stacked high refractive index material, SiO ₂ layer of low refractive index material 2
L1 is laminated. Hereinafter, Ti of high refractive index material is formed on the upper surface of the low refractive index material SiO ₂ layer 2L1.
O ₂ layers and SiO ₂ layers of low refractive index material are sequentially laminated alternately, and the top film layer of the inorganic thin film 2 is laminated with SiO ₂ layers 2L30 of low refractive index material, 30 layers each, a total of 60 layers The inorganic thin film 2 is formed.

Next, the configuration of the inorganic thin film 2 will be described in detail.
In the description of the film thickness configuration described below, a value of optical film thickness nd = 1 / 4λ is used. Specifically, the film thickness of the high refractive index layer (H) is expressed as 1H, and the film thickness of the low refractive index layer (L) is similarly 1L.
Is written. In addition, the notation of S in (xH, yL) S indicates that the configuration in parentheses is periodically repeated by the number of repetitions called the number of stacks.

The film thickness configuration (optical film thickness) of the inorganic thin film 2 is such that the design wavelength λ is 550 nm, the first layer high refractive index material TiO ₂ layer 2H1 is 0.60H, and the second layer low refractive index material SiO ₂ layer. 2L1 is 0.20
L, hereinafter 1.05H, 0.37L, (0.68H, 0.53L) 4, 0.69H,
0.42L, 0.59H, 1.92L, (1.38H, 1.38L) 6, 1.48H, 1
. 52L, 1.65H, 1.71L, 1.54H, 1.59L, 1.42H, 1.58L
1.51H, 1.72L, 1.84H, 1.80L, 1.67H, 1.77L, (1.
87H, 1.87L) 7, 1.89H, 1.90L, 1.90H, and the SiO ₂ layer 2L30, which is the outermost low refractive index material, is 0.96L, for a total of 60 layers.
On the outermost SiO ₂ layer 2L30 in the inorganic thin film 2, a fluorine-containing organic silicon compound film 5 is formed with a thickness of about 5 nm by vacuum deposition.

The optical multilayer filter 10 thus configured has the following functions.
FIG. 2 is a cross-sectional view of the optical multilayer filter provided with a ground.
The film thickness of the fluorine-containing organosilicon compound film 5 of the optical multilayer filter 10 is thin, and the SiO ₂ layer 2L30 formed thereunder is in a state of low density and low insulation.
For this reason, the electric charge generated on the surface of the fluorine-containing organic silicon compound film 5 passes through the fluorine-containing organic silicon compound film 5 and the SiO ₂ layer 2L30 and moves to the TiO ₂ layer 2H30. This T
Since the iO ₂ layer 2H30 has a lower resistance than SiO ₂ , charges can move in the TiO ₂ layer 2H30. The ground cable 15 is attached to the surface of the fluorine-containing organosilicon compound film 5.
By connecting 0, electric charge can pass from the TiO ₂ layer 2H30 through the SiO ₂ layer 2L30 and the fluorine-containing organosilicon compound film 5 to the outside through the ground cable 150.
In this manner, the amount of charge (charge amount) generated on the surface of the fluorine-containing organosilicon compound film 5 in the optical multilayer filter 10 can be reduced.
In addition, since the surface of the optical multilayer filter 10 is the fluorine-containing organic silicon compound film 5, the surface energy is small, and dust once attached can be easily removed.

(Method for producing optical multilayer filter)
Hereinafter, a method for manufacturing the optical multilayer filter will be described.
First, the inorganic thin film 2 is formed on the glass substrate 1 by electron beam vapor deposition (so-called IAD method) using general ion assist.
Specifically, after the glass substrate 1 was mounted in a vacuum deposition chamber (not shown), a crucible filled with a deposition material was placed in the lower portion of the vacuum deposition chamber and evaporated by an electron beam. At the same time, accelerated irradiation with oxygen ionized by an ion gun (adding argon when forming a TiO ₂ film) causes the TiO ₂ high refractive index material layers 2H1 to 2H30 on the glass substrate 1.
And SiO ₂ low refractive index material layers 2L1 to 2L30 are alternately formed in the above-described film thickness configuration.

The film forming conditions for the SiO ₂ layer and the TiO ₂ layer are shown below. The high density forming part was formed under the following standard conditions.
<SiO ₂ layer deposition conditions (standard conditions)>
Deposition rate: 0.8 nm / sec
Acceleration voltage: 1000V
Acceleration current: 1200mA
Oxygen (O ₂ ) flow rate: 70 sccm
Deposition temperature: 150 ° C

<TiO ₂ layer deposition conditions (standard conditions)>
Deposition rate: 0.3 nm / sec
Acceleration voltage: 1000V
Acceleration current: 1200mA
Oxygen (O ₂ ) flow rate: 60 sccm
Argon (Ar) flow rate: 20 sccm
Deposition temperature: 150 ° C

Here, when forming the outermost SiO ₂ layer (2L30 in FIG. 1) in the inorganic thin film 2, the acceleration voltage and acceleration current of the ion gun are set to 0 (zero) (the oxygen gas flow rate to be introduced is By controlling), the pressure in the film forming apparatus is changed to control the density. That is, the outermost SiO ₂ layer is formed by a vacuum deposition method that is not ion-assisted deposition. The pressure at the time of forming the SiO ₂ layer at this time is 5 × 10 ^{−4 to} 5 × 10 ⁻² Pa. Incidentally, the SiO ₂ layer which is deposited by vacuum evaporation are not ion-assisted deposition, low-density SiO ₂ layer is formed in comparison with the SiO ₂ layer was deposited by ion-assisted deposition.

Next, the outermost SiO ₂ layer (2L30 in FIG. 1) and the fluorine-containing organosilicon compound film (
In order to improve the adhesiveness of 5) in FIG. 1, surface treatment is performed on the surface of the outermost SiO ₂ layer. Then, a fluorine-containing organosilicon compound film is formed on the surface of the outermost SiO ₂ layer subjected to the surface treatment. Finally, an optical multilayer filter 10 as shown in FIG. 1 is obtained.
The surface treatment of the outermost SiO ₂ layer is performed using an ion gun under the following conditions.
<Surface treatment conditions for SiO ₂ layer>
Oxygen (O ₂ ) flow rate: 50 sccm
Acceleration voltage: 1000V
Acceleration current: 1000 mA
Chamber temperature: 150 ° C
Processing time: 3 minutes

For example, the fluorine-containing organic silicon compound film is formed by diluting a fluorine-containing organic silicon compound (product name KY-130) manufactured by Shin-Etsu Chemical Co., Ltd. with a fluorine-based solvent (manufactured by Sumitomo 3M Limited: Novec HFE-7200). Then, a solution having a solid content concentration of 3% is prepared, and 1 g of this is impregnated into a porous ceramic pellet and dried, and then used as an evaporation source.
As other fluorine-containing organosilicon compounds, product name: KP-801, which is a fluorine-containing organosilicon compound manufactured by Shin-Etsu Chemical Co., Ltd. Product name: Optool DSX, dem, which is a fluorine-containing organosilicon compound manufactured by Daikin Industries, Ltd. Nam series S-100 or the like can be used.
In the formation of the fluorine-containing organic silicon compound film 5, first, the glass substrate 1 on which the inorganic thin film 2 is formed and the evaporation source are set in a vacuum apparatus and evacuated under reduced pressure. And the temperature of the substrate is about 60 ℃
In this state, the evaporation source is heated to about 600 ° C. to evaporate the fluorine-containing organosilicon compound and form a film on the substrate.
In this embodiment, a vacuum deposition apparatus having two chambers connected in a reduced-pressure atmosphere is used, and a surface treatment is performed in the first chamber before forming a multilayered inorganic thin film and forming a fluorine-containing organosilicon compound film in the second chamber. Then, a fluorine-containing organosilicon compound film was formed.
In addition, you may utilize the separate apparatus which isolate | separated said 2 chambers, surface treatment before formation of multilayer film formation of an inorganic thin film and a fluorine-containing organosilicon compound film in the same vacuum chamber, and fluorine-containing organic A silicon compound film may be formed.

[Verification test 1]
Confirmation test 1 creates a large number of samples in which the formation conditions of the outermost SiO ₂ layer (2L30 in FIG. 1) in the inorganic thin film 2 are changed, and evaluates the performance of each formed sample (inorganic thin film 2). It was.
Samples were prepared using white plate glass having a diameter of 30 mm and a thickness of 0.3 mm (refractive index, n = 1.5).
An inorganic thin film 2 having an outermost SiO ₂ layer with different formation conditions was formed on the surface of 2). Except the SiO ₂ layer of the outermost layer is formed under standard conditions as described above, formation of the outermost layer of the SiO ₂ layer, the pressure in the film forming apparatus by controlling the O ₂ gas flow rate of introducing (vacuum) Changed and went.

The created sample is in a state where the acceleration voltage and acceleration current of the ion gun are 0 (zero),
Degree of vacuum in film forming apparatus 0.0005 Pa, 0.0010 Pa, 0.0030 Pa, 0.01
After forming the outermost SiO ₂ layer at 00 Pa, 0.0300 Pa, and 0.0500 Pa, a fluorine-containing organosilicon compound film was formed by the method described above. The created samples are represented as Examples 1 to 6 in this order.

In addition, the ion gun is operated with the gas introduced so as to have the same pressure as in Examples 1 to 6 (
An outermost SiO ₂ layer of the inorganic thin film 2 was formed with an acceleration voltage of 1000 V and an acceleration current of 1200 mA, and a sample in which a fluorine-containing organosilicon compound film was formed on the surface was prepared. Samples prepared at a degree of vacuum corresponding to Examples 1 to 6 are represented as Comparative Examples 1 to 6 in this order. However,
In Comparative Examples 1 to 3, since the ion gun did not operate because the pressure was too low, the outermost layer SiO ₂
A film could not be formed.

Furthermore, the sample in which the fluorine-containing organosilicon compound film | membrane was not formed with respect to Examples 1-6 and Comparative Examples 1-6 was created as a comparative example. Samples corresponding to Examples 1 to 6 and Comparative Examples 1 to 6 are represented as Comparative Examples 7 to 18 in this order. However, in Comparative Examples 13 to 15, since the ion gun did not operate because the pressure was too low, the outermost SiO ₂ film could not be formed.

Samples of Examples 1 to 6, Comparative Examples 1 to 6 and Comparative Examples 7 to 18 thus created were
Performance evaluation was performed according to evaluation items of a wiping test, surface resistance (sheet resistance) measurement, and surface potential measurement. In addition, evaluation was also performed by measuring the density of the SiO ₂ film using another sample in which the SiO ₂ film was formed on the Si wafer under the conditions for forming the outermost SiO ₂ film.
The evaluation method for each evaluation item is shown below.

(Evaluation methods)
(1) Wiping test The wiping test was carried out by measuring the contact angle before and after the wiping test, measuring the number of beads attached by static electricity (electrostatic test), and measuring the number of beads attached by air blow (air blow test) after the electrostatic test. .
(1-1) Contact angle measurement Using a contact angle meter ("CA-D type", manufactured by Kyowa Kagaku Co., Ltd.), the contact angle of pure water was measured by the droplet method.
(1-2) Static electricity test While applying a load of 1 kg to the surface of the inorganic thin film 2 with Bencott (100% cellulose), 30
After rubbing back and forth (waiting for 60 seconds), gently contact the polyethylene beads (average particle size 10 μm). After that, with the bead-attached surface facing down, it was stopped for 10 seconds and then 3 mm with a microscope.
The area | region of * 2.3mm was observed and the adhering bead was counted. Ten locations were counted and the average was taken as the amount of adhesion. The environment at the time of measurement is humidity 55% ± 5% and air temperature 25 ° C. ± 3 ° C. The measurement was performed such that the surface of the multilayer film was in electrical contact with the human body.
(1-3) Air blow test After the static electricity test, the distance between the air gun and the surface of each sample on which the inorganic thin film is formed is 50c.
m, and dry air was blown onto the substrate surface for 10 seconds at a pressure of 0.1 MPa, and then the beads remaining on (attached to) the surface were counted. Measurement environment is 55% ± 5% humidity, 25 ° C ± 3 ° C
It is.
(2) Surface resistance (sheet resistance) measurement The surface resistance of each sample was measured. FIG. 3 is an explanatory view showing an aspect of measuring the surface resistance of a sample.
In FIG. 3, the surface resistance was measured using a surface resistance measuring device (manufactured by Mitsubishi Chemical, Hirester UP MCP-HT45) 504. The surface resistance measuring device 504 is a probe 50
1 is in contact with the surface of the sample 502. A stage 506 on which the sample 502 is placed is made of Teflon (registered trademark). The measurement conditions are 1000 V and 30 sec. The environment at the time of measurement is humidity 55% ± 5% and air temperature 25 ° C. ± 3 ° C.
(3) Surface potential measurement The surface of each sample on which an inorganic thin film was formed was strongly rubbed with Bencott (100% cellulose), and after applying static electricity so that the initial surface potential was about 2000 V, 60 seconds later The surface potential of each inorganic thin film was measured.
FIG. 4 is an explanatory diagram showing an aspect of measuring the surface potential of a sample.
In FIG. 4, the surface potential is measured by a surface potentiometer (manufactured by Trek Japan, Model 34).
1) 500 was used. The surface potential meter 500 measures the probe 501 and the sample 502.
The distance from the surface was set to 10 mm. Note that the stage 503 on which the sample 502 is placed is made of metal, and measurement was performed with the stage 503 grounded. The environment at the time of measurement is humidity 55% ± 5% and air temperature 25 ° C. ± 3 ° C.

The density measurement of the outermost SiO ₂ layer performed in combination with each of the above evaluation items was performed after forming the SiO ₂ film to a thickness of about 200 nm on the Si wafer under the conditions for forming each outermost SiO ₂ layer. ,
The density was measured by GIXR (X-ray reflectometry method apparatus: manufactured by Rigaku Corporation, ATX-G).

FIG. 5 includes the measurement of the density of the outermost SiO ₂ layer. The evaluation results in the wiping test (contact angle measurement, electrostatic test and air blow test), surface resistance (sheet resistance) measurement, and surface potential measurement are shown in Examples 1 to 3. 6 and the conditions for forming an inorganic thin film of Comparative Examples 1 to 18.

In FIG. 5, when the SiO ₂ film is formed (IAD method) while assisting with an ion gun (Comparative Examples 4 to 6, Comparative Examples 16 to 18), the film density of the SiO ₂ film is 2.2 g / theoretical density.
It exceeds cm ³ . This cause is considered to be due to implantation of O (oxygen) atoms by assist. When the output of the ion gun is set to 0 (zero), the density decreases. Further, depending on the pressure (degree of vacuum) during film formation, the higher the pressure, the lower the density. This is considered to be because the mean free path of the evaporated particles becomes longer as the pressure becomes lower, and the energy when reaching the substrate becomes higher. In the confirmation test 1, the film formation rate decreased at a pressure higher than that in Example 6, and the general allowable film formation rate of 0.8 nm / sec could not be maintained.

The number of beads attached before the wiping test is about 100 to 300 in Examples 1 to 6,
In Comparative Examples 4 to 6 and Comparative Examples 16 to 18, the number is about 500 to 600. Thus, it can be seen that Examples 1-6 have a smaller number of beads attached than Comparative Examples 4-6 and Comparative Examples 16-18.
This is due to the density difference of the uppermost layer of the SiO ₂ layer in the inorganic thin film 2, the outermost layer SiO ₂
In Examples 1 to 6 in which the layer density is low, the sheet resistance is low and the surface potential is also low, which is considered to be caused by the difference in charge amount. Therefore, even in Comparative Examples 7 to 12 having no fluorine-containing organosilicon compound film, the number of beads attached is almost the same as that of Examples 1 to 6.

Next, a case where an air blow test is performed on a sample to which beads are attached will be considered.
In Examples 1 to 6, the number of adhered beads after performing the air blow test is 10 to 30,
The number of adhesions has decreased rapidly. On the other hand, Comparative Examples 7 to 12 have more beads than Examples 1 to 6 although the number of beads attached decreased in the air blow test. This is due to the presence or absence of a fluorine-containing organosilicon compound film on the surface. In Examples 1 to 6 in which the fluorine-containing organosilicon compound film was formed, the surface energy was small, so the ability to hold the beads was lowered, and the attached beads Can be easily removed. On the other hand, Comparative Examples 7 to 12 having no fluorine-containing organosilicon compound film have a high surface energy, so the ability to hold the beads is high, and the attached beads cannot be easily removed. This is clear from the measurement results of the contact angle, and Examples 1 to
6, the contact angle is 107 to 110 °, whereas in Comparative Examples 7 to 12, the contact angle is 42 to 49 °. Moreover, since there is no big difference in sheet resistance and surface potential in both, it turns out that it is not the difference resulting from a charge amount. Moreover, it is the same reason that the adhesion amount after the air blow test of Comparative Examples 4 to 6 is smaller than that of Comparative Examples 16 to 18.

Therefore, the density of the outermost SiO ₂ layer constituting the inorganic thin film 2 is 1.9-2.
It can be said that the range of 1 g / cm ³ is preferable. This is a SiO ₂ film density 1.981g / cm ³ of the Example 6, the theoretical density of the SiO ₂ film is 2.2 g / cm ³ (Comparative Examples 4 to 7 and Comparative deposited by IAD process Exceeds Examples 16-18).

Moreover, there is no big difference in sheet resistance and surface potential between Examples 1-6 and Comparative Examples 7-12, and Comparative Examples 4-6 and Comparative Examples 16-18. Therefore, the fluorine-containing organosilicon compound film does not affect the static elimination effect due to the low density of the SiO ₂ layer.
As described above, in order to prevent dust and dust from adhering to the surface, it is effective to reduce the density of the outermost SiO ₂ layer of the inorganic thin film 2 and remove charges due to static electricity, etc. It is effective to form a fluorine-containing organosilicon compound film on the surface so that the dust and dust can be easily removed.

In the case of Examples 1 to 6, there is no great difference in the adhesion level of beads before and after the wiping test, the adhesion level of beads after the air blow test, and the contact angle. On the other hand, in Comparative Examples 4 to 6, the contact angle greatly decreased before and after the wiping test, and accordingly, the number of beads attached after the air blow test increased. Therefore, in Examples 1-6, it turns out that durability of a fluorine-containing organosilicon compound film is high.

[Confirmation test 2]
Confirmation Test 2 is the result obtained in Confirmation Test 1 (the outermost layer Si constituting the inorganic thin film 2).
A density of the O ₂ layer is preferably about 1.9 to 2.1 g / cm ³ ), and a TiO ₂ layer formed under the outermost SiO ₂ layer constituting the inorganic thin film 2 is included. A sample in the case where the SiO ₂ layer was formed at a low density was prepared and its performance was evaluated. The outermost low-density SiO ₂ layer, the low-density TiO ₂ layer formed in the lower layer, and the low-density SiO ₂ layer are the low-density formation portion.

First, prior to the confirmation test 2, the adhesion of the low density SiO ₂ layer and the low density TiO ₂ layer was confirmed.
Check adhesion of the low-density SiO ₂ layer is deposited to a diameter 30 mm, the surface of the white plate glass having a thickness of 0.3 mm, a TiO ₂ layer of thickness at standard conditions of the TiO ₂ layer is about 100nm indicated above On the surface, the film thickness is about 1 under the same film formation conditions as in Examples 1 to 6 in the confirmation test 1 (see FIG. 5).
Six types of samples in which a low-density SiO ₂ layer of 00 nm was formed were prepared. Therefore, the density of the formed SiO ₂ layer is the same as in Examples 1 to 6 (see FIG. 5). The prepared samples are referred to as Samples 1 to 6 in the order of formation conditions corresponding to Examples 1 to 6.

On the other hand, ensure adhesion of the low-density TiO ₂ layer of likewise diameter 30 mm, on the surface using a white plate glass having a thickness of 0.3 mm, similarly thickness at standard conditions of the SiO ₂ layer shown above is about 100
The nm of SiO ₂ film is formed on the surface of the SiO ₂ film, and the sample thickness at standard conditions of the TiO ₂ layer was deposited a TiO ₂ layer of about 100nm as a comparative sample, the acceleration voltage of the ion gun and With the acceleration current set to 0 (zero), the degree of vacuum in the film forming apparatus is 0.014 Pa, 0.030 Pa,
A total of five types of samples were prepared including four types of samples in which low-density TiO ₂ layers each having a thickness of about 100 nm were formed under film forming conditions of 0.040 Pa and 0.050 Pa. That is, the low-density TiO ₂ layer was formed by a vacuum deposition method that is not ion-assisted deposition. Incidentally, the TiO ₂ layer which is deposited by vacuum evaporation are not ion-assisted deposition, low-density TiO ₂ layer is formed as compared to the TiO ₂ layer was deposited by ion-assisted deposition.
The prepared samples are referred to as Samples 11 to 15 in this order.

The prepared samples 1 to 6 and samples 11 to 15 were evaluated for the adhesion of the SiO ₂ film and the TiO ₂ film by a cross-cut tape test based on JIS standard K5600-5-6.
The cross-cut tape test was performed using a SiO ₂ film formed on the surface of each sample and T
The surface of the iO ₂ film was scratched vertically and horizontally with a cutter (100-mass cross-cut) using a cutter, and after the tape was applied to the surface, the film peeling caused by peeling the tape was as follows: Evaluation was performed according to a three-level evaluation standard.
A: The edge of the crosscut is completely smooth, and there is no peeling in any lattice eye.
B: There is a small peeling of the film at the cross-cut intersection (5% or less out of 100 squares).
C: The film is peeled along the edge of the crosscut and / or at the intersection (100
Of the mass, more than 5% and less than 15%).

FIG. 6 shows the adhesion evaluation results of Samples 1 to 6 with the SiO ₂ layer formed together with the film formation conditions. FIG. 7 shows the adhesion evaluation results of Samples 11 to 15 with the TiO ₂ layer formed together with the film formation conditions.
In FIG. 6, samples 1 to 6 having a low-density SiO ₂ layer formed on the surface all show good adhesion (A) regardless of the film forming conditions.
On the other hand, in FIG. 7, in the case of the TiO ₂ layer, the adhesiveness is lowered in accordance with the density of the TiO ₂ film is reduced. And since the adhesive evaluation result of the sample 13 is A, low density Ti
It can be said that the density of the TiO ₂ film when used as the O ₂ layer is preferably 4.1 g / cm ³ or more. The density of the TiO ₂ film also in the sample 11 formed a dense TiO ₂ film by ion-assisted deposition are 4.89 g / cm ^3. This value can be further improved by changing ion assist conditions, etc., but is preferable because it causes an increase in compressive stress and a decrease in HAZE value (transparency) as the density increases. Absent.
Therefore, the preferable range of the density in the low density TiO ₂ layer is 4.1 to 4.8 g / cm ^3.
It can be said that.

Based on the above results, as a low-density TiO ₂ layer formed below the outermost SiO ₂ layer, for example, formation conditions in the sample 12 (the acceleration voltage and acceleration current of the ion gun are 0 (zero))
, The degree of vacuum is 0.014 Pa), and includes the outermost SiO ₂ layer, and the low-density SiO ₂ layer formed below the SiO ₂ layer is formed under the same formation conditions (acceleration voltage and acceleration of the ion gun). A new sample was prepared with an electric current of 0 (zero) and a degree of vacuum of 0.003 Pa.

Samples, SiO ₂ layer are sequentially formed under TiO ₂ layer and the standard conditions formed under standard conditions, are alternately stacked, the inorganic thin film 2 (Fig. Total 60 layers outermost layer is made of SiO ₂ layer of a low density 1)), when the outermost low-density SiO ₂ layer (2L30) is the first layer, the second lower layer (2H)
30) to the sixth layer (2H28), instead of the TiO ₂ layer formed under the standard conditions and the SiO ₂ layer formed under the standard conditions, one layer between the second layer and the sixth layer Sequentially, four types of samples formed with a low-density TiO ₂ layer and a low-density SiO ₂ layer and all the formation layers forming the inorganic thin film 2 (the outermost layer includes a low-density SiO ₂ layer 60) Layer) was formed with a low-density TiO ₂ layer and a low-density SiO ₂ layer.

That is, the sample having one layer of the low density forming portion is composed of SiO 2 having the outermost layer (2L30) having a low density.
_It consists of _two layers. This sample is the same as Example 3 in Confirmation Test 1. In the sample having two layers of the low density formation portion, 2L30 is composed of a low density SiO ₂ layer, and 2H30 is a low density Ti.
It consists of an O ₂ layer. Further, in the sample having three layers of the low density forming portion, 2L30 and 2L29 are composed of a low density SiO ₂ layer, and 2H30 is composed of a low density TiO ₂ layer. Hereinafter, low density S
The number of layers in the low-density forming portion composed of the iO ₂ layer and the low-density TiO ₂ layer is sequentially formed up to the sixth layer. Furthermore, in the sample having 60 low-density layers, 2L30 to 2L1 are low-density SiO _2.
2H30 to 2H1 are formed of a low-density TiO ₂ layer.

The sample in which the inorganic thin film is formed in this way is a sample in which the number of layers of the low density forming portion is one layer.
Samples having 2 to 6 layers and 60 layers of low density layers are referred to as Samples 21 to 26 in this order.
In each sample, an inorganic thin film was formed on the surface of a white plate glass having a diameter of 30 mm and a thickness of 0.3 mm, and then a fluorine-containing organosilicon compound film was formed on the surface in the same manner as in Confirmation Test 1.

When the refractive index (n) of the SiO ₂ layer of the low density forming portion is 1.43, the refractive index (n) of TiO ₂ of the low density forming portion is 2.28, and the design wavelength λ is 550 nm, each sample The physical film thickness of each layer of the SiO ₂ layer of the low density forming portion and the TiO ₂ layer of the low density forming portion formed in FIG. 1 is shown below (the optical film thickness is shown in the film thickness configuration of the inorganic thin film 2 described above). .
1st layer (2L30): 62.8 nm, 2nd layer (2H30): 50.6 nm, 3rd layer (2
L29): 31.7 nm, 4th layer (2H29): 50.9 nm, 5th layer (2L28): 3
2.2 nm, 6th layer (2H28): 51.4 nm.
That is, the total film thickness of the low-density formation part is 62.8 nm, 113.4 nm, 145.2 nm in the order of the number of layers of 1 layer (sample 21) to 6 layers (sample 25) and 60 layers (sample 26). 196
. 0 nm, 228.3 nm, 279.7 nm, and 4374.6 nm.

And, in the same manner as the confirmation test 1, the prepared samples 21 to 26 are evaluated by the evaluation items by the wiping test (contact angle measurement, electrostatic test and air blow test), surface resistance (sheet resistance) measurement, and surface potential measurement. It was.
FIG. 8 is a diagram showing the evaluation results in confirmation test 2. As shown in FIG.
FIG. 8 shows the evaluation results of the wiping test, surface resistance (sheet resistance) measurement, and surface potential measurement in samples 21 to 26, the evaluation result of Example 3 in confirmation test 1, the formed low-density SiO ₂ layer, and TiO _{2. It} includes the measured density of _two layers and shows the conditions for forming each inorganic thin film.

In FIG. 8, the sheet resistance decreases as the number of low density layers increases. But 4
Almost no change from layer to layer.
FIG. 9 is a graph showing the relationship between the number of layers of the low density forming portion and the sheet resistance in the confirmation test 2, and FIG. 10 is a graph showing the relationship between the total film thickness of the low density forming portion and the sheet resistance in the confirmation test 2. is there.
FIG. 9 shows the number of layers of the low density forming portion on the horizontal axis and the sheet resistance (ohm / □) on the vertical axis. Example 3 (number of layers of the low density forming portion 1) and samples 21 to 26 (low density forming) The number of layers is 2 to 6 and 60), and is a line diagram connecting plot points of sheet resistance values. FIG. 10 is a diagram in which the horizontal axis represents the total film thickness of the low-density forming portion, the vertical axis represents the sheet resistance (ohm / □), and the plot of the sheet resistance value of each sample is connected as in FIG. Show.

The diagram shown in FIG. 9 clearly shows that the sheet resistance value is saturated and hardly changed when the number of low-density forming portions is four or more.
Next, among these samples, the case where the number of layers of the low density formation part is 1 (Example 3), the case where the number of layers of the low density formation part is 4 (Sample 23), and all of the 60 layers In the case of a low density formation part (Sample 2
The time-dependent change in wavelength spectral characteristics in 6) was confirmed. The wavelength spectral characteristics were measured using an integrating sphere type spectral transmittance measuring device.

FIG. 11 is a graph showing wavelength dispersion characteristics in Example 3 of Confirmation Test 1.
FIG. 11 shows the wavelength (nm) on the horizontal axis and the transmittance (%) on the vertical axis.
It is the diagram which plotted the transmittance | permeability for every wavelength 2nm in 0 nm (between a visible light region and a part of near-infrared light region).
Therefore, all of the inorganic thin films formed on the samples of Example 3 and Samples 23 to 26 have an IR cut function.

The confirmation of the change with time is the half value on the UV (ultraviolet ray) side indicated by point A in the diagram shown in FIG.
Transmittance 50%), the wavelength immediately after film formation of each sample at the half value on the IR (infrared) side indicated by point B, and the wavelength when 30 days had elapsed after film formation.
FIG. 12 is a graph showing the change with time of the wavelength at the half value on the UV side.
A diagram a1 shown by a broken line in FIG. 12 shows a change over time in Example 3 (the number of layers of the low density forming portion is one layer), and a diagram b1 shown by a solid line is the sample 23 (the number of layers of the low density forming portion is (4 layers), a diagram c1 indicated by a one-dot chain line shows a change with time in the sample 26 (all of the 60 layers are low density formation portions).

On the other hand, FIG. 13 is a graph showing the change with time of the wavelength at the half value on the IR side. In FIG. 13, a diagram a2 shown by a broken line shows a change with time in Example 3, and a diagram b2 shown by a solid line shows Sample 2
3. A diagram c2 indicated by a one-dot chain line shows a change with time in the sample 26.
In each graph, the vertical axis in FIG. 12 indicates a wavelength range of 400 to 420 nm, and the vertical axis in FIG. 13 indicates a wavelength range of 670 to 690 nm.

In FIGS. 12 and 13, both the wavelength change with time at the UV half value and the wavelength change with time at the IR half value increase as the number of low-density films increases. For this reason, there is almost no change in half value up to the four layers shown in the diagrams b1 and b2, and the sheet resistance is saturated in the four layers (see FIG. 9). It can be said that the number of layers is preferably 1 to 4 layers. That is, the outermost layer includes the inorganic thin film 2 composed of at least a low-density SiO ₂ layer, or the outermost SiO ₂ layer, and the outermost layer S
When the iO ₂ layer is the first layer, the TiO ₂ layer and Si formed in the second to fourth layers below the iO ₂ layer
It can be said that it is preferable to selectively form the O ₂ layer in the low density formation portion. In other words, when the outermost SiO ₂ layer is the first layer, it can be said that it is preferable that the low density formation portion is formed selectively in the first to fourth layers.
On the other hand, from the diagram shown in FIG. 10, in other words from the aspect of the total film thickness of the low-density formation part, the total film thickness (physical film thickness) of the low-density formation part includes the outermost SiO ₂ layer and the outermost layer. _{2 on} the lower layer side of the SiO ₂ layer
It can be said that the thickness is preferably within 80 nm.

In the above embodiment, although it demonstrated using white plate glass as the glass substrate 1, it is not limited to this, BK7, sapphire glass, borosilicate glass, blue plate glass, SF3, and S
A transparent substrate such as F7 may be used, and commercially available optical glass may also be used.
Moreover, although the case where TiO ₂ was used as the material of the high refractive index layer has been described, Ta ₂ O ₅ , N
b ₂ O ₅ can also be applied.
Further, a fluorine-containing organic silicon compound film 5 was provided on the outermost SiO ₂ layer (2L30) of the inorganic thin film 2, but an alkyl compound (for example, manufactured by Shin-Etsu Chemical Co., Ltd .: K
F-96) can be used, and the same effect as in the above embodiment can be obtained.

As described above, according to the present embodiment, at least the SiO ₂ layer (2
By the density of the L30) and ^{1.9g / cm 3 ~2.1g / cm 3} , an insulating SiO ₂ layer showing the original high insulating property decreases (conductivity increases). Therefore, charges existing on the surface due to static electricity or the like can pass through the outermost SiO ₂ layer and reach the lower layer.
The lower high-refractive index material has a lower insulating property than the SiO ₂ layer, so that charges can move on the surface of the high-refractive index film. By grounding this charge, it is difficult for the charge to accumulate on the outermost surface of the optical multilayer filter, and dust and the like due to static electricity are less likely to be attached.
Further, since the fluorine-containing organosilicon compound film 5 is formed on the SiO ₂ layer (2L30) constituting the outermost layer of the inorganic thin film 2, the surface energy is reduced, dust adhesion is suppressed, and once adhered. Dust can be easily removed. Furthermore, since the fluorine-containing organic silicon compound film 5 to be formed is thin (<10 nm) and has a lower density than inorganic materials,
It is easy to pass charges through the lower layer, and the spectral characteristics are not affected.
If the density of the outermost SiO ₂ layer in the inorganic thin film 2 is low, the surface area of the SiO ₂ increases (corresponding to the increase in microscopic unevenness), and the area to which the fluorine-containing organosilicon compound film 5 adheres is large. Become. Therefore, the adhesiveness of the fluorine-containing organosilicon compound film 5 is improved and the durability is improved.
Furthermore, when the outermost SiO ₂ layer of the inorganic thin film 2 is the first layer, the first SiO ₂ layer (
2L30) in the lower layer (2H30) and the fourth layer (2H29), the density is 4.1 g /
The density is 1.9 g / c in the TiO ₂ layer of cm ^{3 to} 4.8 g / cm ³ and the third layer (2L29).
By selectively forming the SiO ₂ layer of m ^{3 to} 2.1 g / cm ³ , the same effect as described above can be obtained, and an optical multilayer filter with little change in wavelength dispersion characteristics with time can be obtained.
In addition to the TiO ₂ layer formed in the first layer (2L30), the second layer (2H30) and the fourth layer (2H29) of the inorganic thin film 2, and the third SiO ₂ layer (2L29), high quality Since a film can be formed, characteristics such as low wavelength shift and low HAZE necessary for the optical multilayer filter 10 are easily obtained.

Further, in the optical multilayer filter 10 of the present embodiment, the substrate is composed of the glass substrate 1, so that it can be used as a dust-proof glass for a video device such as a CCD (Charge Coupled Device) that is not easily dusted and has a desired filter function. For example, an optical multilayer filter including a UV-IR cut filter and an IR cut filter function can be obtained.
Further, since the glass substrate 1 is made of a quartz substrate, for example, an optical low-pass filter which is not easily dusty and has a desired filter function integrally formed, for example, UV
An optical low-pass filter including an IR cut filter and an IR cut filter function can be obtained. The present embodiment can also be applied to the formation of an antireflection film.

Further, according to the method for manufacturing an optical multilayer filter of the present embodiment, the density is 1.9 g / cm by forming the SiO ₂ layer (2L30) constituting at least the outermost layer of the inorganic thin film 2 by a vacuum deposition method. A SiO ₂ layer of ^{3 to} 2.1 g / cm ³ can be obtained. As a result, the insulating property of the SiO ₂ layer, which originally exhibits high insulating properties, is lowered (conductivity is increased). Therefore, charges existing on the surface due to static electricity or the like can pass through the outermost SiO ₂ layer and reach the lower layer. The lower high-refractive index material has a lower insulating property than the SiO ₂ layer, so that charges can move on the surface of the high-refractive index film. By grounding (depressing) this electric charge, it becomes difficult for the electric charge to collect on the outermost surface of the optical multilayer filter 10, and an optical multilayer filter that is less likely to be dusted due to static electricity is obtained.
Further, a TiO ₂ layer formed under the outermost SiO ₂ layer (2L30) of the inorganic thin film 2,
By forming by a vacuum deposition method, it is possible to density obtain TiO ₂ layer of ^{4.1g / cm 3 ~4.8g / cm 3} . Then, when the outermost SiO ₂ layer (2L30) of the inorganic thin film 2 is the first layer, the _second layer (2H30) and the fourth layer (2H2) below the first SiO ₂ layer
The TiO ₂ layer formed in 9) and the SiO ₂ layer formed in the third layer (2L29) are selectively formed using a vacuum deposition method, so that at least the outermost SiO 2 layer of the inorganic thin film 2 is formed.
An optical multilayer filter having the same effect as that obtained when the _two layers are formed by vacuum deposition is obtained.
Furthermore, since the fluorine-containing organosilicon compound film 5 is formed on the SiO ₂ layer constituting the outermost layer of the inorganic thin film 2, the surface energy is reduced, dust adhesion is suppressed, and dust once adhered is easy. Thus, an optical multilayer filter that can be removed easily is obtained. In addition,
Since the film thickness of the fluorine-containing organic silicon compound film 5 to be formed is thin and the density is lower than that of the inorganic material,
It is easy to pass charges through the lower layer, and the spectral characteristics are not affected. Further, when the density of the outermost SiO ₂ layer in the inorganic thin film 2 is low, the surface area of the SiO ₂ layer increases and the area to which the fluorine-containing organosilicon compound film 5 adheres increases. Therefore, the adhesiveness of the fluorine-containing organosilicon compound film 5 is improved, and an optical multilayer filter with improved durability is obtained.

In addition, when the SiO ₂ layer (2L30) constituting the outermost layer of the inorganic thin film 2 and the SiO ₂ layer of the outermost layer are set as the first layer, it is selected as the third layer (2L29) below the first SiO ₂ layer When the pressure at the time of forming the SiO ₂ layer to be formed is 5 × 10 ^{−4 to} 5 × 10 ⁻² Pa, the density is 1
. It can be set to 9 to 2.1 g / cm ³ . Also, the outermost SiO ₂ layer (2L30) is 1
As the first layer, the _second layer (2H30) and the fourth layer (2H29) below the first SiO ₂ layer
The pressure at the time of forming the TiO ₂ layer that is selectively formed in the above is 1.4 × 10 ⁻² Pa to 3 × 10 ^−.
By setting it to ² Pa, the density can be set to 4.1 to 4.8 g / cm ³ .

As described above, the optical multilayer filter 10 manufactured by the method for manufacturing the optical multilayer filter according to the present embodiment includes, for example, an imaging device such as a digital still camera and a digital video camera, a mobile phone with a camera, and a portable personal computer with a camera. As a (personal computer), it can be effectively used as an electronic device apparatus in which the influence of dust is suppressed.
An example in which an optical multilayer filter is used in an imaging device of a digital still camera that captures a still image among these electronic device devices will be described.
FIG. 14 is an explanatory diagram showing a configuration of a digital still camera using the optical multilayer film filter according to the present embodiment, and shows the configuration of the imaging module 100 and an imaging apparatus including the imaging module 100.
The imaging module 100 includes a cover glass 115, an optical low-pass filter 110, and a CCD (charge coupled device) 120 that is an imaging device that electrically converts an optical image.

The optical low-pass filter 110 has a density of 1.9 to 2.1 g / cm ³ of the SiO ₂ layer (2L30) constituting the outermost layer of the inorganic thin film 2 (see FIG. 1) on the surface thereof. UV-IR in which a fluorine-containing organosilicon compound film 5 is formed on the SiO ₂ layer constituting the outermost layer
A cut filter is formed. In this case, the filter substrate is a quartz substrate.
The optical low-pass filter 110 is a part that directly touches the outside air by changing a lens of a digital still camera or the like, and is a part where dust is most easily attached. The fixing jig 140 for fixing the optical low-pass filter 110 is made of a conductive material such as metal and is electrically connected to the outermost layer (surface) of the optical low-pass filter 110. And fixing jig 1
40 is grounded by a ground cable 150.

The imaging module 100, a lens 200 disposed on the light incident side, a drive unit 130 that drives the CCD 120 of the imaging module 100, and a main body unit 300 that records and reproduces an imaging signal output from the imaging module 100 The image pickup apparatus is configured. In addition,
Although not shown, the main body 300 is reproduced by a signal processing unit that corrects an imaging signal, a recording unit that records the imaging signal on a recording medium such as a magnetic tape, and a reproducing unit that reproduces the imaging signal. This includes components such as a display unit that displays the video. The digital still camera configured as described above provides a digital still camera that can be easily removed by air blow, and the surface of the optical low-pass filter 110 that is likely to be directly attached to the outside air and is likely to adhere dust is less likely to adhere to the dust. can do.

The imaging module 100 has been described with a structure in which the lens 200 is disposed separately.
The imaging module including the lens 200 may be configured.
In addition, the present embodiment can be applied to an antireflection film formed on the surface of the cover glass 115.
In addition, a multilayer filter can be formed on the surface of the cover glass 115.
Further, the cover glass 115 may be made of quartz and may be a cover glass that also serves as a part of the optical low-pass filter. And antireflection film and multilayer filter (UV-IR) formed on the surface
(Cut filter) and the like.
When this embodiment is applied to these cover glasses, dust adhering in the assembly process of the imaging device can be reduced.
Furthermore, even if it is the structure which forms an anti-reflective film in the surface side of an optical low-pass filter, it can implement.

Sectional drawing which shows the structure of the optical multilayer filter which concerns on this embodiment. Sectional drawing when earth | ground is provided in the optical multilayer film filter which concerns on this embodiment. Explanatory drawing which shows the aspect which measures the surface resistance of a sample. Explanatory drawing which shows the aspect which measures the surface potential of a sample. The figure which shows the evaluation result in the confirmation test 1. FIG. It shows the formation conditions of adhesion of the sample SiO ₂ layer formed evaluation results and film. It shows a low-density TiO ₂ layer adhesion of the formed sample evaluation results and film formation conditions. The figure which shows the evaluation result in the confirmation test 2. FIG. The graph which shows the relationship between the number of layers of the low density formation part in the confirmation test 2, and sheet resistance. The graph which shows the relationship between the total film thickness of the low density formation part in the confirmation test 2, and sheet resistance. The graph which shows the wavelength dispersion characteristic in Example 3 of the confirmation test 1. FIG. The graph which shows the time-dependent change of the wavelength in the half value on the UV side. The graph which shows the time-dependent change of the wavelength in the half value by the side of IR. Explanatory drawing which shows the structure of the digital still camera using the optical multilayer film filter which concerns on this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Glass substrate as a substrate, 2 ... Inorganic thin film, 5 ... Fluorine containing organosilicon compound film, 10
... optical multilayer filter, 100 ... imaging module, 110 ... optical low-pass filter, 11
5 ... cover glass, 120 ... CCD, 130 ... drive unit, 140 ... fixing jig, 150 ... earth cable, 200 ... lens.

Claims (8)

An optical multilayer filter having an inorganic thin film composed of a plurality of layers on a substrate,
The inorganic thin film is composed of a low density formation part and a high density formation part,
A fluorine-containing organosilicon compound film is formed on the surface of the inorganic thin film;
In the low density formation portion, the outermost layer of the inorganic thin film or a plurality of layers including the outermost layer is formed from at least one of a low density titanium oxide layer or a low density silicon oxide layer,
The high-density formed portion includes a silicon oxide layer having a higher density than the low-density silicon oxide and a titanium oxide layer having a higher density than the low-density titanium oxide layer between the low-density formed portion and the substrate. And is formed by stacking
An optical multilayer filter, wherein the total film thickness of the low density forming portion is within 280 nm. The optical multilayer filter according to claim 1, wherein
The density of the low density silicon oxide layer is 1.9 to 2.1 g / cm ³ , and the density of the low density titanium oxide layer is 4.1 to 4.8 g / cm ³ ,
The outermost layer of the inorganic thin film is formed of the low density silicon oxide layer,
An optical multilayer filter, wherein the number of layers of the low density forming portion is selected by selecting any one of the second to fourth layers. The optical multilayer filter according to claim 1 or 2,
An optical multilayer filter, wherein the substrate is a glass substrate or a quartz substrate. A method for producing an optical multilayer filter having an inorganic thin film comprising a plurality of layers on a substrate,
Forming a high-density forming portion in which a high-density titanium oxide layer and a high-density silicon oxide layer are stacked on the surface of the substrate;
Next, at least one of a titanium oxide layer having a density lower than that of the high-density titanium oxide layer and a silicon oxide layer having a density lower than that of the high-density silicon oxide layer is formed on the surface of the high-density forming portion by vacuum deposition. The low density formation part formed from the above is formed with a total film thickness within 280 nm,
Furthermore, a fluorine-containing organic silicon compound film is formed on the surface of the outermost layer of the low-density forming part. In the manufacturing method of the optical multilayer filter according to claim 4,
The density of the low density silicon oxide layer is 1.9 to 2.1 g / cm ³ , the density of the low density titanium oxide layer is 4.1 to 4.8 g / cm ³ , and the layer of the low density formation portion A method for producing an optical multilayer filter, wherein the number is selected from two to four layers. A method for producing an optical multilayer filter according to claim 4 or claim 5,
The pressure when the low-density silicon oxide layer is formed by the vacuum evaporation method is 5 × 10 ⁻⁴ to
5 × 10 ⁻² Pa,
The pressure when forming the low-density titanium oxide layer by the vacuum deposition method is 1.4 × 1.
The manufacturing method of the optical multilayer filter characterized by being 0 ^<-2 > ^-3 * 10 ^<-2 > Pa. An electronic device in which an optical multilayer filter is incorporated, wherein the optical multilayer filter is composed of an inorganic thin film composed of a plurality of layers on a substrate and a fluorine-containing organosilicon compound film formed on the surface of the inorganic thin film,
The inorganic thin film is composed of a low density forming portion and a high density forming portion,
In the low density formation portion, the outermost layer of the inorganic thin film or a plurality of layers including the outermost layer is formed from at least one of a low density titanium oxide layer or a low density silicon oxide layer,
The high-density formed portion includes a silicon oxide layer having a higher density than the low-density silicon oxide and a titanium oxide layer having a higher density than the low-density titanium oxide layer between the low-density formed portion and the substrate. And is formed by stacking
An electronic device apparatus, wherein an optical multilayer filter having a total film thickness of 280 nm or less in the low density forming portion is incorporated. The electronic apparatus device according to claim 7,
The density of the low density silicon oxide layer is 1.9 to 2.1 g / cm ³ , the density of the low density titanium oxide layer is 4.1 to 4.8 g / cm ³ , and the layer of the low density formation portion An electronic apparatus comprising an optical multilayer filter formed by selecting any one of two to four layers.

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