JP2009282088A - Absorption type multi-layer film nd filter and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorption type multi-layer film ND filter, restraining a change in spectral transmission characteristics due to oxidation of a metal film and shifting to the long wavelength side of the spectral transmission characteristics. <P>SOLUTION: An oxide dielectric film and the metal film are alternately stacked at least on one side of a resin substrate to obtain the absorption type multi-layer film ND filter. After that, the absorption type multi-layer film ND filter is held between dust-free paper sheets, and subjected to temperature and relative humidity processing in an atmosphere containing oxygen. The absorption type multi-layer film ND filter is preferably subjected to the temperature and relative humidity processing under the temperature-humidity conditions such as a temperature of 30°C-70°C, both inclusive, and a humidity of 50% or more, after the sheet-like filter is held between the dust-free paper sheets and stacked, or a long filter is held between the dust-free paper sheets and taken up to form a roll. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet-shaped or roll-shaped absorption multilayer ND filter that suppresses temporal change in spectral transmission characteristics between wavelengths of 400 to 700 nm and a method for manufacturing the same.

  As an ND filter (Neutral Density Filter), a reflection type ND filter that reflects and attenuates incident light and an absorption type ND filter that absorbs and attenuates incident light are known. When an ND filter is incorporated in a lens optical system in which reflected light is a problem, an absorption ND filter is generally used. The absorption type ND filter includes a type in which an absorbing substance is mixed with the substrate itself (colored glass filter) and a type in which the absorption material is applied to the substrate, as well as a type in which the substrate itself does not absorb and the thin film formed on the surface has absorption. Exists. If the thin film has absorption, the thin film is composed of a multilayer film (absorbing multilayer film) to prevent reflection on the surface of the thin film so that it has the function of attenuating transmitted light and has an antireflection effect. ing.

In Patent Document 1, an absorption film M _x O _y made of a metal oxide that attenuates the amount of transmitted light is provided on a substrate, and the oxygen ratio (y / x) of the absorption film M _x O _y is perpendicular to the film thickness direction. An ND filter changing in various directions is disclosed. In addition, the step of forming the absorption film M _x O _y and the step of forming the multilayer antireflection multilayer film are performed in an atmosphere having a substrate temperature of less than 150 ° C., and then at a temperature of 100 ° C. to 130 ° C. A method of manufacturing an ND filter by performing a heat treatment in air has also been proposed.

  In the above method, the heat treatment is performed in the air for 1 hour in the range of 100 ° C. to 130 ° C. after the formation of the antireflection film. This is because a plastic substrate is used. The temperature needs to be lower than 150 ° C. As a result, there arises a problem that the sealing density of the film is lowered and the environmental resistance is inferior. Therefore, the sealing density of the film is improved by this heat treatment.

Patent Document 2 proposes a method of manufacturing a thin-film ND filter that can attenuate the amount of light uniformly in the visible range and has excellent durability. In this production method, a mixed gas containing oxygen is introduced into the metal materials Ti, Cr and Ni as raw materials at the time of film formation, a light absorption film is formed on the transparent substrate by vapor deposition, and SiO ₂ and Al ₂ O are further formed. _A thin film type ND filter is formed by laminating _three dielectric films.

  In this method, after a light absorption film and a dielectric film are laminated on a transparent substrate, the change in optical characteristics is saturated by heating in an oxygen atmosphere containing 10% or more of oxygen. That is, the initial optical characteristics are changed in advance so that the change in transmission density at visible wavelengths after heating becomes ± 0.01 or less.

Patent Document 3 proposes an ND filter that can suppress deterioration over time regardless of the intensity of incident light, and a method for manufacturing the ND filter. This ND filter has a light-transmitting substrate having a softening point higher than the aging treatment temperature, and is formed on the substrate, and is relatively resistant to corrosion such as Inconel, stainless steel, Ti, Au, Ag, Nb, Ta, and Zr. Light absorption layer such as high metal, metal nitride film such as TiN _x , NbN _x , TaN _x , AlN _x , or metal oxide film such as TiO _y , Al ₂ O _3, and the substrate and the light absorption layer And an oxide underlayer composed of the constituent elements of the substrate or the light absorption layer.

  In this ND filter manufacturing method, the aging treatment is performed at a temperature of 350 ° C. or higher and lower than the softening point of the substrate. It has been shown that aging treatment at a temperature of 350 ° C. or higher can suppress changes with time in light absorption characteristics.

JP 2004-212462 A JP 2003-043211 A JP 2005-338385 A

  In Patent Documents 2 and 3, as described above, the heat treatment is performed at a predetermined temperature, and it is considered that the change in transmittance can be saturated to some extent. The problem of shifting the characteristic to the longer wavelength side has not been solved.

  The present invention has been made paying attention to such a conventional problem, and an absorption multilayer film formed by alternately laminating an oxide dielectric film and a metal film is provided on at least one surface of a resin substrate. In the absorption multilayer ND filter, the spectral transmission characteristics that are suppressed by the change in the spectral transmission characteristics caused by the oxidation of the metal film of the absorption multilayer ND filter and cannot be solved by the conventional heat treatment are described. The purpose is to solve the problem of shifting to the longer wavelength side.

  In order to solve the above-mentioned problems, the present inventor has made a change in the transmittance of the absorption multilayer ND filter with time after the production of the absorption multilayer ND filter, that is, a change in transmittance or ND expressed by oxidation of the metal film. An earnest investigation and research were conducted on the effect of the heat treatment method after the ND filter was produced on the shift of the transmittance to the long wavelength side that occurs when the filter was used.

  As a result, in an absorptive multilayer ND filter provided with an absorptive multilayer film in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a resin substrate, the absorptive multilayer film is provided on the resin substrate. After laminating, it was found that the above-mentioned problems can be solved by sandwiching the obtained absorption multilayer ND filter between dust-free paper and treating the temperature and humidity in an oxygen-containing atmosphere.

  That is, in the method for manufacturing an absorption multilayer ND filter provided by the present invention, an absorption multilayer film in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a resin substrate is provided. In the manufacturing method of the multilayer ND filter, after the absorption multilayer film is laminated on the resin substrate, the obtained absorption multilayer film ND filter is sandwiched between dust-free papers and subjected to temperature and humidity treatment in an oxygen-containing atmosphere. It is characterized by.

  In the manufacturing method of the present invention, the absorption multilayer ND filter sandwiched between dust-free paper is in the form of a sheet, and the sheet-like absorption multilayer ND filter is stacked in a state of being sandwiched between dust-free paper. It is preferable to form a humidity treatment stack and subject the temperature / humidity treatment stack to a temperature / humidity treatment. Alternatively, the absorption multi-layer film ND filter sandwiched between dust-free paper is long, and the temperature-humidity treatment roll is wound by winding the long absorption multi-layer film ND filter between dust-free paper. A body may be formed and the temperature and humidity treatment roll body may be subjected to temperature and humidity treatment.

  The dust-free paper used in the production method of the present invention is preferably dust-free paper having low dust generation and flatness, or embossed dust-free paper having convex portions. In the case of embossed dust-free paper having convex portions, the height of the convex portions is more preferably 20 μm or more.

Furthermore, in the manufacturing method of the present invention, it is preferable that the temperature and humidity treatment is performed under temperature and humidity conditions of a temperature of 30 ° C. or higher and 70 ° C. or lower and a humidity of 50% or higher. Processing time of the temperature and humidity treatment, the average transmittance between a wavelength 400~700nm absorption type multi-layer film ND filter only by laminating the absorption type multi-layer film without temperature and humidity treatment as T _1, the temperature 80 ° C. Humidity When the average transmittance between wavelengths 400 to 700 nm of the absorption multilayer film ND filter when the standard temperature and humidity treatment is performed at 90% for 24 hours is T ₀ , a predetermined value selected from the range of the temperature and humidity conditions is used. The average transmittance T between wavelengths 400 to 700 nm of the absorption-type multilayer ND filter after being subjected to temperature and humidity treatment at temperature and humidity,
(T−T ₁ ) / (T ₀ −T ₁ ) ≧ 0.95
It is preferable to be determined so as to satisfy

  Further, the absorption multilayer film ND filter provided by the present invention is provided with an absorption multilayer film in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a resin substrate. After the absorption multilayer film is laminated, the obtained absorption multilayer film ND filter is sandwiched between dust-free papers, and is processed by temperature and humidity treatment in an oxygen-containing atmosphere.

  According to the present invention, it is possible to saturate a change in spectral transmission characteristic associated with oxidation of a metal film and to saturate a shift to a longer wavelength side of a spectral transmission characteristic that is observed when used for a long time. As a result, it is possible to suppress changes over time, and it is possible to obtain an absorption-type multilayer ND filter having a higher spectral transmission characteristic than that of a conventional absorption-type multilayer ND filter, which is industrially useful. It is.

  Hereinafter, embodiments of the present invention will be described in detail. The present invention relates to an absorption multilayer ND filter manufacturing method in which an absorption multilayer film in which an oxide dielectric film and a metal film are alternately laminated is provided on at least one surface of a resin substrate. After the multilayer films are laminated, the obtained absorption multilayer film ND filter is sandwiched between dust-free papers and is subjected to temperature and humidity treatment in an oxygen-containing atmosphere.

  By performing the temperature and humidity treatment in this way, the change in the spectral transmission characteristics associated with the oxidation of the metal film is saturated, and the shift to the longer wavelength side of the spectral transmission characteristics that are observed after a long period of use is saturated. Can do.

  The resin plate or resin film that is the resin substrate of the absorption multilayer ND filter of the present invention includes polyethylene terephthalate (PET), polyethersulfone (PES), polyarylate (PAR), polycarbonate (PC), and polyolefin (PO). And a resin plate or resin film selected from the resin material of norbornene, or an acrylic organic film covering at least one surface of the resin plate or resin film selected from the resin material And is composed of a complex.

An absorption multilayer film is provided by alternately laminating oxide dielectric films and metal films on at least one surface of the resin substrate. For the oxide dielectric film constituting the absorption multilayer film, it is preferable to use a dielectric layer of any one of SiO ₂ , Al ₂ O ₃ or a mixture thereof. Moreover, it is preferable to use a metal layer containing Ni as a main component for the metal film constituting the absorption multilayer film. The metal layer mainly composed of Ni is preferably made of a Ni-based alloy material to which one or more elements selected from Ti, Al, V, W, Ta, and Si are added.

  The addition ratio of the element added to Ni is 5 to 15% by weight for Ti element, 3 to 8% by weight for Al element, 3 to 9% by weight for V element, and 18 for W element. It is preferable to be in the range of ˜32% by weight, 5-12% by weight in the case of Ta element, and 2-6% by weight in the case of Si element.

  Next, the absorption multilayer ND filter on which the absorption multilayer is laminated is sandwiched between dust-free paper. For example, in the case of a long absorption multilayer film ND filter wound up in a roll shape by roll-to-roll, after the absorption multilayer film is laminated, the absorption multilayer film ND filter is sandwiched between dust-free papers. A roll body for temperature and humidity treatment is formed by winding. The temperature and humidity treatment roll body described later is subjected to the temperature and humidity treatment roll body.

  In addition, in the case of a sheet-like absorption multilayer ND filter in which an oxide dielectric film and a metal film are alternately laminated on at least one surface of a sheet-like resin film substrate, or in a roll shape by roll-to-roll. In the case of a sheet-like absorption multilayer film ND filter obtained by cutting into a sheet shape while unwinding the obtained long absorption multilayer film ND filter, the sheets are stacked while being sandwiched between dust-free paper Thus, a stack is formed, and the stack is subjected to temperature and humidity treatment.

  The dust-free paper is preferably one that does not cause dust transfer to the absorption multilayer ND filter during the temperature and humidity treatment, and is preferably dust-free paper having low dust generation and flatness. Moreover, you may use the embossed dust-free paper which has a convex part. For example, dust-free paper impregnated with an acrylic resin that prevents the fibers from dropping off, and synthetic paper, recyclable clean paper RC (manufactured by Sakurai Co., Ltd.), and the like can be used.

  Among the dust-free papers, dust-free paper impregnated with a resin in order to prevent the fibers from dropping off is particularly preferable. A type in which a special resin is impregnated based on a natural paper with low dust generation is more preferable, and a type in which an acrylic resin is impregnated is more preferable. Further, embossed dustless paper may be used.

  The height of the convex portion of the embossed dust-free paper is preferably 20 μm or more and 50 μm or less, and more preferably 30 μm or more and 40 μm or less. If the convex part of embossed dust-free paper is less than 20 μm, the gap when the above-mentioned absorption multilayer film ND filter is sandwiched between the embossed dust-free paper having the convex part is narrowed, and is generated by temperature and humidity treatment in an oxygen-containing atmosphere Moisture that is absorbed is less likely to be absorbed by the absorption multilayer ND filter. As a result, it is not preferable to shift the spectral transmission characteristics, which are observed to occur over a long period of time, to the longer wavelength side during the temperature and humidity treatment.

  On the other hand, if the convex portion exceeds 50 μm, a gap when the absorbent multilayer film ND filter is sandwiched between the embossed dust-free paper having the convex portion is widened, which may cause trouble in handling. That is, in the case of a sheet, the temperature and humidity treatment is performed in units of 100 to 200 sheets. Therefore, if the convex portions of the emboss are high, they will wobble when stacked. In the case of a roll, since the dust-free paper is wound up during the temperature and humidity treatment, it is difficult to wind up if the convex portion is high. It should be noted that if the number of stacked sheets is large, transfer of the convex portion is likely to occur.

  Next, a temperature and humidity process is performed in which the absorption multilayer ND filter sandwiched between dust-free paper as described above is held for a predetermined time in an oxygen-containing atmosphere maintained at a predetermined temperature and humidity. The predetermined temperature and humidity are preferably 30 ° C. or higher and 70 ° C. or lower and 50% or higher humidity, more preferably 60 ° C. or higher and 70 ° C. or lower, and 75% or higher and 90% or lower.

  If the temperature is lower than 30 ° C., the metal film cannot be sufficiently oxidized during the temperature and humidity treatment, and the change in spectral transmission characteristics due to the oxidation of the metal film cannot be saturated. On the other hand, when the temperature exceeds 70 ° C., the change in the spectral transmission characteristic that appears due to oxidation of the metal film can be saturated, but this is not preferable because distortion occurs in the resin film substrate and fine cracks occur in the film.

  On the other hand, by applying humidity, it has been observed that the shift to the longer wavelength side of the spectral transmission characteristic that is observed after a long period of use can be saturated, and if the humidity is less than 50%, Moisture absorbed by the absorption-type multilayer ND filter becomes insufficient (the refractive index changes due to the absorption of moisture, causing a shift), and the long-term use of the spectral transmission characteristics, which are recognized to occur, is on the longer wavelength side This is not preferable because the shift of the above cannot be saturated.

  In general, air can be used as the oxygen-containing atmosphere, but other gases can be used as long as they have an oxygen concentration capable of oxidizing the metal film and saturating the change in spectral transmission characteristics. May be. Such an oxygen concentration is preferably about 20% by volume or more.

  Desirably, the processing time required for the temperature and humidity treatment is appropriately determined according to the temperature and humidity conditions of the temperature and humidity during the temperature and humidity treatment. Specifically, the average transmittance T between wavelengths 400 to 700 nm of the absorption multilayer film ND filter after performing the temperature and humidity treatment at a predetermined temperature and humidity selected from the range of the above temperature and humidity conditions is as follows. Processing time can be set to meet requirements.

That is, the average transmittance between a wavelength 400~700nm absorption type multi-layer film ND filter only by laminating the absorption type multi-layer film without temperature and humidity treatment as T _1, reference 24 hours at a temperature 80 ° C. and 90% humidity The average transmittance between wavelengths 400 to 700 nm of the absorption multilayer ND filter when the temperature and humidity treatment is performed is T ₀ , and the difference (T ₀ -T ₁ ) between these T ₀ and T ₁ is the reference shift amount ( when X ₀₎ is defined as 100 percent, as the shift amount obtained from the difference between T and _{T 1 (T-T 1)} (X) is equal to or greater than 95% of the reference shift amount _{(X 0),} The processing time for the temperature and humidity processing is determined.

  In addition, the temperature and humidity treatment for 24 hours at the temperature of 80 ° C. and the humidity of 90% is effective in a short time although the resin film substrate is distorted or the micro crack is generated in the film as described above. Therefore, in the present invention, the temperature / humidity process is set as the reference temperature / humidity process. The requirement for determining the above processing time is expressed by the following equation (1).

[Formula 1]
(T−T ₁ ) / (T ₀ −T ₁ ) = X / X ₀ ≧ 0.95

If the value of the shift amount X with respect to the reference shift amount X ₀ is less than 95%, the temperature and humidity treatment is insufficient, when actually using the absorption type multi-layer film ND filter, the spectral transmission characteristics due to oxidation of the metal film And a change in transmittance due to a shift of the spectral transmission characteristic to the longer wavelength side cannot be suppressed. Note that the processing time required for the temperature and humidity treatment is a function of the temperature and humidity, actually advance determined by experiment the relation between the value and the processing time of X / X ₀ as described above for each condition of temperature and humidity The temperature and humidity treatment may be performed according to the experimental results.

  As described above, the absorptive multilayer ND filter obtained by the manufacturing method of the present invention is obtained by alternately laminating an oxide dielectric film and a metal film on at least one surface of a resin substrate, and then the absorptive multilayer ND filter. The filter is obtained by sandwiching a filter between dust-free paper and treating the temperature and humidity in an oxygen-containing atmosphere.

  By applying temperature and humidity treatment to the absorption-type multilayer ND filter in this way, the change in spectral transmission characteristics is saturated, and the long wavelength of the spectral transmission characteristics that has not been considered in the past and can be observed after long-term use. Side shifts can also be saturated. As a result, it is possible to suppress a change with time, and it is possible to provide an absorption multilayer ND filter having higher spectral transmission characteristics than that of a conventional absorption multilayer ND filter.

[Example 1]
Select polyethylene terephthalate (hereinafter referred to as PET film) (manufactured by Toyobo Co., Ltd.) as the substrate of the absorption type multilayer ND filter, which has high heat resistance, high transparency in the visible wavelength range, and low water absorption. did. An absorptive multilayer film was formed on this PET film using a sputtering roll coater apparatus (manufactured by Hirano Kotone Co., Ltd.) schematically shown in FIG.

Specifically, after setting the PET film 6 (thickness 100 μm, width 280 mm) on the unwinding roll 1, the PET film 6 is unwound from the unwinding roll 1, conveyed along the cooling can 3, and wound on the winding roll 2. Then, an oxide dielectric film is formed on one side of the PET film 6 by sputtering using the oxide dielectric film target 4 for forming an SiO ₂ film that is an oxide dielectric film. As a result, the PET film 6 on which the oxide dielectric film is formed is temporarily wound around the winding roll 2.

Next, the Ni roll, which is a metal film, is formed while the PET roll 6 is transported along the cooling can 3 using the take-up roll 2 as the unwind roll and the previous unwind roll 1 as the take-up roll. A metal film is formed by sputtering using the metal film target 5 for this purpose. As a result, the PET film 6 on which the metal film is formed is temporarily wound around the winding roll 1. By repeating these operations, an absorption multilayer film was formed by alternately laminating three layers of SiO ₂ films as oxide dielectric films and two layers of Ni films as metal films on one side. .

Further, the PET film 6 having been deposited on one side is wound upside down, and the same operation as the above operation is performed on the side of the resin film that has not been deposited, and three layers of SiO 2 are formed as an oxide dielectric film. _Two films and two Ni films as metal films were alternately stacked one by one to form an absorption multilayer film. As a result, an absorption type having a configuration shown in Table 1 below, in which three layers of SiO ₂ films as oxide dielectric films and two layers of Ni films as metal films are alternately stacked on both sides, respectively. A multilayer film was formed.

A target (manufactured by Asahi Glass Ceramics Co., Ltd.) in which Si is added to SiC was used as the oxide dielectric film target 4 for forming the SiO ₂ film, which is an oxide dielectric film. Using this oxide dielectric film target 4, an Ar gas was introduced, and a SiO ₂ film was formed by introducing a dual magnetron sputtering method while introducing an oxygen gas. The Ar gas pressure was 5 Pa, and the oxygen gas introduction amount was controlled by an impedance monitor.

  Moreover, the target (made by Sumitomo Metal Mining Co., Ltd.) added with Ni-Ti 8% was used for the metal film target 5 for forming the Ni film, which is a metal film. Using this metal film target 5, Ar gas was introduced and an Ar gas pressure was set to 5 Pa to form a metal film by DC magnetron sputtering.

<Temperature and humidity treatment>
The absorption-type multilayer ND filter formed as described above is taken out from the sputtering roll coater shown in FIG. 1, and is sandwiched between two dust-free papers (manufactured by Oohiro Paper Co., Ltd.) while being unwound from the roll. (Length 330 mm, width 280 mm). As the dust-free paper, an embossed paper having a thickness of 0.08 mm, a convex portion height of 30 μm, a length of 330 mm, and a width of 280 mm was used.

  100 sets of absorption multilayer ND filters sandwiched between two dust-free papers were stacked and placed in the chamber 11 of the environmental testing machine 10 (manufactured by ESPEC Corporation) shown in FIG. The chamber 11 is provided with a heater (not shown) so that the inside of the chamber 11 can be set to a predetermined temperature. In addition, a container 13 having an open top is installed in the chamber 11, and gas is blown into the water held therein from a nozzle 15 provided at the tip of the gas supply line 14, whereby the chamber The humidity and gas composition in 11 can be adjusted.

In Example 1, after introducing air from the gas supply line 14 to make the inside of the chamber 11 an oxygen-containing atmosphere, a temperature and humidity treatment was performed at a temperature of 70 ° C. and a humidity of 80% for 48 hours. Incidentally, 48 hours is this process time, that satisfy Equation 1 above with respect to the reference shift amount X ₀ based on the standard temperature and humidity treatment was selected as the condition.

  FIG. 3 shows the measurement results of the spectral transmission characteristics of the absorption type multilayer ND filter after the temperature and humidity treatment thus obtained, together with the measurement results before the temperature and humidity treatment. A self-recording spectrophotometer (manufactured by JASCO Corporation) was used for measuring the spectral transmission characteristics. The measurement result of the spectral transmission characteristics of the absorption multilayer ND filter before the temperature and humidity treatment is indicated by a one-dot chain line as “before the temperature and humidity treatment”. This alternate long and short dash line shows a transmittance of about 12.5% at 485 nm and 645 nm.

  The measurement result of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature and humidity treatment is indicated by a dotted line as “after the temperature and humidity treatment”. This dotted line shows a transmittance of about 13.5% at 485 nm and a transmittance of about 12.8% at 645 nm. From these measurement results, it was found that the transmittance increased by about 1.0% at 485 nm on the short wavelength side and the transmittance increased by about 0.3% at 645 nm on the long wavelength side by performing the temperature and humidity treatment. I understand. This indicates that an absorption-type multilayer ND filter having high stability with respect to spectral transmission characteristics is obtained, as will be described later.

<Weather resistance evaluation test>
Next, in order to evaluate whether or not the absorption multilayer ND filter subjected to the temperature and humidity treatment has high stability with respect to spectral transmission characteristics, a weather resistance evaluation test was performed. Specifically, an absorption type multilayer ND filter subjected to the above temperature and humidity treatment is disposed in the environmental testing machine 10 (manufactured by Espec Co., Ltd.) shown in FIG. After making the inside into an oxygen-containing atmosphere, it was placed in an environment of a temperature of 80 ° C. and a humidity of 90% for 24 hours.

  The spectral transmission characteristics of this absorption multilayer ND filter were measured. The measurement result after the weather resistance evaluation test of the absorption multilayer ND filter subjected to the temperature and humidity treatment is shown as a “weather resistance evaluation” in FIG. 3 by a solid line. For reference, the measurement result of the absorption multilayer ND filter when the reference temperature and humidity treatment is performed is indicated by a broken line in FIG. 3 as “after the reference temperature and humidity treatment at 80 ° C. and 90% for 24 hours”.

From these measurement results shown in FIG. 3, the shift amount (X) of the average transmittance resulting from performing various processes can be obtained. Specifically, the shift amount (X) resulting from performing the temperature and humidity treatment for 48 hours at the temperature of 70 ° C. and the humidity of 80%, which is the treatment condition of Example 1, is the value between the dotted line value and the dashed line value. The shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment can be obtained from the difference between the solid line value and the alternate long and short dash line value. Further, the reference shift amount (X ₀ ) resulting from the reference temperature / humidity treatment can be obtained from the difference between the broken line value and the alternate long and short dash line value in FIG.

As a result, the average transmittance shift amount (X) resulting from performing the temperature and humidity treatment under the processing conditions of Example 1 with respect to the reference shift amount (X ₀ ) is 98%. The average transmittance shift amount (X) resulting from conducting a weather resistance evaluation test in addition to the treatment was 99%, which was hardly changed.

  Next, among the measurement results shown in FIG. 3, the spectral transmission characteristics after the temperature and humidity treatment and the spectral characteristics after the weather resistance evaluation test so that the change in the spectral transmission characteristics for each wavelength before and after the weather resistance evaluation test becomes clear. The transmission characteristics are extracted and shown in FIG.

  As can be seen from FIG. 4, the absorption multilayer ND filter subjected to the temperature and humidity treatment has a spectral transmission characteristic from 400 nm to 700 nm even when exposed to an environment of 80 ° C. and 90% humidity for 24 hours. Almost no change over the wavelength range. That is, the absorption-type multilayer ND filter that has been subjected to the temperature and humidity treatment in advance has a spectral transmission characteristic that is not shifted to the long wavelength side by the weather resistance evaluation test.

[Comparative Example 1]
Absorption was performed in the same manner as in Example 1 except that the absorption-type multilayer ND filter was not sandwiched between dust-free paper during the temperature / humidity treatment and that the treatment time for the temperature / humidity treatment was set to 96 hours instead of 48 hours. The mold multilayer ND filter was subjected to a temperature and humidity treatment and then subjected to a weather resistance evaluation test. In this temperature and humidity treatment, the films are brought into close contact with each other, the change in spectral transmission characteristics due to oxidation of the metal film hardly occurs, and moisture absorption is insufficient.

  FIG. 5 shows the measurement results of the spectral transmission characteristics of the absorption-type multilayer ND filter after the temperature and humidity treatment with a dotted line as “after the temperature and humidity treatment”, and the measurement results of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was determined from these measurement results, the shift amount (X caused by the temperature and humidity treatment performed under the processing conditions of Comparative Example 1 with respect to the reference shift amount (X ₀ ). ) Was 93%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was greatly changed.

[Comparative Example 2]
Example 1 except that nitrogen was supplied from the gas supply line of the environmental testing machine 10 shown in FIG. 2 to make the inside of the environmental testing machine 10 a nitrogen atmosphere and the temperature and humidity treatment time was set to 96 hours instead of 48 hours. In the same manner as above, the absorption type multilayer ND filter was subjected to a temperature and humidity treatment, and a weather resistance evaluation test was conducted.

  FIG. 6 shows the measurement results of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature / humidity treatment by a dotted line as “after the temperature / humidity treatment”, and the measurement results of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by performing the temperature and humidity treatment under the processing conditions of Comparative Example 2 with respect to the reference shift amount (X ₀ ). ) Was 92%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was greatly changed. In addition, as can be seen from the opening of the dotted line and the solid line for each wavelength, the transmittance is greatly increased on the short wavelength side compared to the long wavelength side, and the spectral transmission characteristics are increased on the long wavelength side by performing a weather resistance evaluation test. Shifted to.

[Comparative Example 3]
Instead of performing the temperature and humidity treatment for 48 hours at a temperature of 70 ° C. and a humidity of 80%, the samples were left at room temperature and normal humidity for 30 days, and then subjected to a weather resistance evaluation test.

  FIG. 7 shows the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter after being left for 30 days at room temperature and humidity as a dotted line “After 30 days at room temperature and humidity”, and after the weather resistance evaluation test. The measurement results of the spectral transmission characteristics are shown as a “weather resistance evaluation” by a solid line. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X) resulting from standing at room temperature and humidity for 30 days was 93% with respect to the reference shift amount (X ₀ ). On the other hand, the shift amount (X) resulting from conducting the weather resistance evaluation test in addition to the normal temperature and normal humidity treatment was 99%, which was greatly changed. In addition, as can be seen from the opening of the dotted line and the solid line for each wavelength, the transmittance is greatly increased on the short wavelength side compared to the long wavelength side, and the spectral transmission characteristics are increased on the long wavelength side by performing a weather resistance evaluation test. Shifted to.

[Example 2]
A temperature-humidity treatment was applied to the absorption multilayer ND filter in the same manner as in Example 1 except that the humidity treatment was performed at a temperature of 30 ° C. and a humidity of 50% instead of a temperature of 70 ° C. and a humidity of 80%. went

  FIG. 8 shows the measurement result of the spectral transmission characteristic of the absorption multilayer ND filter after the temperature and humidity treatment as a dotted line as “after the temperature and humidity treatment”, and the measurement result of the spectral transmission characteristic after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was determined from these measurement results, the shift amount (X caused by the temperature and humidity treatment performed under the processing conditions of Example 2 with respect to the reference shift amount (X ₀ ). ) Was 98%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, and was almost unchanged and stable. In addition, the dotted line and the solid line almost coincided with each other in the wavelength region from 400 nm to 700 nm, and the spectral transmission characteristic was not shifted to the long wavelength side by the weather resistance evaluation test.

[Comparative Example 4]
A temperature and humidity treatment was performed on the absorption multilayer ND filter in the same manner as in Example 1 except that a temperature and humidity treatment was performed at 25 ° C. instead of a temperature of 70 ° C., and a weather resistance evaluation test was performed.

  FIG. 9 shows the measurement results of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature / humidity treatment with a dotted line as “after the temperature / humidity treatment”, and the measurement results of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by performing the temperature and humidity treatment under the processing conditions of Comparative Example 4 with respect to the reference shift amount (X ₀ ). ) Was 92%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was greatly changed. In addition, as can be seen from the opening of the dotted line and the solid line for each wavelength, the transmittance is greatly increased on the short wavelength side compared to the long wavelength side, and the spectral transmission characteristics are increased on the long wavelength side by performing a weather resistance evaluation test. Shifted to.

[Comparative Example 5]
A temperature and humidity treatment was performed on the absorption multilayer ND filter in the same manner as in Example 1 except that the temperature and humidity treatment was performed at 40% instead of the humidity of 80%, and a weather resistance evaluation test was performed.

  FIG. 10 shows the measurement result of the spectral transmission characteristic of the absorption multilayer ND filter after the temperature and humidity treatment as a dotted line as “after the temperature and humidity treatment”, and the measurement result of the spectral transmission characteristic after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by the temperature and humidity treatment being performed under the processing conditions of Comparative Example 5 with respect to the reference shift amount (X ₀ ). ) Was 91%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was greatly changed. In addition, as can be seen from the opening of the dotted line and the solid line for each wavelength, the transmittance is greatly increased on the short wavelength side compared to the long wavelength side, and the spectral transmission characteristics are increased on the long wavelength side by performing a weather resistance evaluation test. Shifted to.

[Comparative Example 6]
A temperature and humidity treatment was performed on the absorption multilayer ND filter in the same manner as in Example 1 except that the temperature and humidity treatment was performed at 80 ° C. instead of the temperature of 70 ° C., and a weather resistance evaluation test was performed.

  FIG. 11 shows the measurement results of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature / humidity treatment with a dotted line as “after the temperature / humidity treatment”, and the measurement results of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by the temperature and humidity treatment being performed under the processing conditions of Comparative Example 6 with respect to the reference shift amount (X ₀ ). ) Was 98%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which remained stable with almost no change. Distortion occurred in the PET film, and fine cracks occurred in the film.

[Comparative Example 7]
Except that the height of the convex part of the embossed dust-free paper was less than 20 μm, the absorption type multilayer film ND filter was subjected to temperature and humidity treatment in the same manner as in Example 1 and then subjected to a weather resistance evaluation test.

  FIG. 12 shows the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature and humidity treatment as a dotted line as “after the temperature and humidity treatment”, and the measurement result of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by performing the temperature and humidity treatment under the processing conditions of Comparative Example 7 with respect to the reference shift amount (X ₀ ). ) Was 91%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was greatly changed. In addition, as can be seen from the opening of the dotted line and the solid line for each wavelength, the transmittance is greatly increased on the short wavelength side compared to the long wavelength side, and the spectral transmission characteristics are increased on the long wavelength side by performing a weather resistance evaluation test. Shifted to.

[Example 3]
Absorptive multilayer film ND in the same manner as in Example 1 except that dust-free paper (manufactured by Ooyo Paper Co., Ltd., thickness 0.08 mm, length 330 mm, width 280 mm) was used instead of embossed dust-free paper having convex portions. The filter was subjected to a temperature and humidity treatment and a weather resistance evaluation test.

  FIG. 13 shows the measurement results of the spectral transmission characteristics of the absorption multilayer ND filter after the temperature / humidity treatment with a dotted line as “after temperature / humidity treatment”, and the measurement results of the spectral transmission characteristics after the weather resistance evaluation test. It is indicated by a solid line as “weather resistance evaluation”. For reference, the measurement result of the spectral transmission characteristics of the absorption multilayer ND filter when the reference temperature / humidity treatment is performed is indicated by a broken line as “after the reference temperature / humidity treatment at 80 ° C. and 90% for 24 hours”.

When the shift amount (X) of the average transmittance was obtained from these measurement results, the shift amount (X caused by performing the temperature and humidity treatment under the processing conditions of Example 3 with respect to the reference shift amount (X ₀ ). ) Was 98%, while the shift amount (X) resulting from the weather resistance evaluation test in addition to the temperature and humidity treatment was 99%, which was stable without significant change. In addition, the dotted line and the solid line almost coincided with each other in the wavelength region from 400 nm to 700 nm, and the spectral transmission characteristic was not shifted to the long wavelength side by the weather resistance evaluation test.

[result]
In Examples 1 and 2, since there was almost no change in the shift amount (X) before and after the weather resistance evaluation test, the absorption-type multilayer film ND filter was sandwiched between embossed dust-free paper and subjected to temperature and humidity treatment. It was found that the change in transmission characteristics can be saturated. In addition, before and after the weather resistance evaluation test, the transmittance hardly changed over the wavelength range from 400 nm to 700 nm. It was found that the shift to the long wavelength side can be saturated. From these results, it was found that the weather resistance is improved by performing the temperature and humidity treatment in advance.

  Also in Example 3, there is almost no change in the shift amount (X) before and after the weather resistance evaluation test, and the transmittance hardly changes over the wavelength region from 400 nm to 700 nm before and after the weather resistance evaluation test. Therefore, even with temperature and humidity treatment using dust-free paper that is not embossed dust-free paper, it is possible to saturate changes in spectral transmission characteristics and shift to the longer wavelength side, resulting in better weather resistance. all right.

  On the other hand, in Comparative Example 1, since dust-free paper was not used during the temperature and humidity treatment, the change in the average transmittance shift amount (X) before and after the weather resistance evaluation test was large, and the weather resistance was not good. . Further, in Comparative Examples 2 to 5, since the temperature and humidity treatment was insufficient, the change in the average transmittance shift amount (X) before and after the weather resistance evaluation test was increased, and the spectral transmission characteristics were on the long wavelength side. The weather resistance was not good.

  Specifically, in Comparative Example 2, the temperature and humidity treatment was performed for a longer time than Example 1, but the change in spectral transmission characteristics was saturated because the temperature and humidity treatment was performed in a nitrogen atmosphere instead of an oxygen-containing atmosphere. I didn't get it. Comparative Example 3 was allowed to stand at room temperature and normal humidity for 30 days, but under these conditions, the change in spectral transmission characteristics was not saturated. The temperature of 25 ° C. and 80% humidity in Comparative Example 4 and the temperature of 70 ° C. and 40% humidity in Comparative Example 5 also did not saturate the change in spectral transmission characteristics.

  In Comparative Example 6, although the weather resistance was stable, the PET film was distorted, and fine cracks were generated in the film, so that it could not be used as an absorption multilayer ND filter.

  In Comparative Example 7, since the height of the convex portion of the embossed dust-free paper was less than 20 μm, the average was measured before and after the weather resistance evaluation test, even though the temperature and humidity treatment was performed under the same temperature and humidity conditions as in Example 1. The change in the transmittance shift amount (X) increased, and the spectral transmission characteristics shifted to the longer wavelength side, and the weather resistance was not good.

It is the schematic of the sputtering roll coater apparatus which laminates | stacks an absorption type multilayer film. It is the schematic of the environmental testing machine used for a temperature / humidity process and a weather resistance evaluation test. Changes in spectral transmission characteristics of the absorption multilayer ND filter when subjected to temperature and humidity conditions in Example 1 of the present invention, and changes in spectral transmission characteristics after the weather resistance evaluation test of the absorption multilayer ND filter It is a graph which shows. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption multilayer film ND filter which carried out the temperature-humidity process of the temperature-humidity conditions of Example 1 of this invention. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 1. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption-type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 2. It is a graph which shows the change of the spectral transmission characteristic before and behind the weather resistance evaluation test of the absorption type multilayer ND filter left to stand for 30 days on the normal temperature normal humidity conditions shown in the comparative example 3. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption multilayer film ND filter which carried out the temperature and humidity process of Example 2 of this invention. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 4. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption-type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 5. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption-type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 6. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption-type multilayer film ND filter processed by the temperature and humidity conditions of the comparative example 7. It is a graph which shows the change of the spectral transmission characteristic before and after the weather resistance evaluation test of the absorption multilayer film ND filter which carried out the temperature and humidity process of Example 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Unwinding roll 2 Winding roll 3 Cooling can 4 Target for oxide dielectric film 5 Target for metal film 6 PET film 10 Environmental test machine

Claims (9)

  In the method for manufacturing an absorption multilayer film ND filter in which an absorption multilayer film formed by alternately laminating oxide dielectric films and metal films is provided on at least one surface of a resin substrate, the absorption multilayer film is provided on the resin substrate. A method of manufacturing an absorptive multilayer ND filter, comprising: laminating and then sandwiching the obtained absorptive multilayer ND filter between dust-free papers and performing a temperature and humidity treatment in an oxygen-containing atmosphere.   The absorption multilayer ND filter sandwiched between the dust-free paper is in the form of a sheet, and the sheet-like absorption multilayer ND filter is stacked in a state sandwiched between the dust-free paper to form a temperature / humidity treatment stack. The method for manufacturing an absorption multilayer ND filter according to claim 1, wherein the temperature / humidity treatment stack is subjected to temperature / humidity treatment.   The absorption multilayer ND filter sandwiched between the dust-free paper has a long shape, and the temperature-humidity treatment roll is wound by winding the elongated absorption multilayer ND filter between the dust-free paper. The method for producing an absorption multilayer ND filter according to claim 1, wherein a body is formed and the temperature and humidity treatment roll body is subjected to temperature and humidity treatment.   The method for producing an absorption-type multilayer ND filter according to any one of claims 1 to 3, wherein the dust-free paper is dust-free paper having low dust generation and flatness.   The method for manufacturing an absorptive multilayer ND filter according to any one of claims 1 to 3, wherein the dust-free paper is embossed dust-free paper having convex portions.   6. The method of manufacturing an absorptive multilayer ND filter according to claim 5, wherein the height of the convex portion of the embossed dust-free paper having the convex portion is 20 μm or more.   The method for producing an absorptive multilayer ND filter according to any one of claims 1 to 6, wherein the temperature and humidity treatment is performed under temperature and humidity conditions of a temperature of 30 ° C or higher and 70 ° C or lower and a humidity of 50% or higher. . The average transmittance between wavelengths 400 to 700 nm of the absorption multilayer film ND filter in which the absorption multilayer film is simply laminated without performing the temperature and humidity treatment is T _1, and the reference temperature and humidity is 24 hours at a temperature of 80 ° C. and a humidity of 90%. When the average transmittance in the wavelength range of 400 to 700 nm of the absorption multilayer ND filter when the treatment is performed is T ₀ , the temperature and humidity treatment is performed at a predetermined temperature and humidity selected from the range of the temperature and humidity conditions. The average transmittance T between wavelengths 400 to 700 nm of the absorption multilayer ND filter after
(T−T ₁ ) / (T ₀ −T ₁ ) ≧ 0.95
The method of manufacturing an absorption-type multilayer ND filter according to claim 7, wherein a treatment time of the temperature and humidity treatment is determined so as to satisfy the above.   An absorptive multilayer ND filter obtained by using the method for producing an absorptive multilayer ND filter according to claim 1.

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