JP5597780B1 - Near-infrared cut filter, method for manufacturing the same, and glasses equipped with the same - Google Patents

Abstract

[PROBLEMS] To reduce the concentration of stress acting on a resin substrate when forming a film on a transparent resin substrate and cut off near-infrared light in the short wavelength region, thereby obtaining stable optical characteristics and improving productivity. Provide a near-infrared cut filter.
A first multilayer film X formed on one surface of a transparent resin substrate 10 blocks near-infrared rays in a short wavelength region, and a second multilayer film Y formed on the other surface has a short wavelength region. By cutting off near-infrared rays in the long-wavelength region other than, the average transmittance of near-infrared rays is cut to 15% or less for the cumulative amount of sunlight with a wavelength region of 770 nm to 1800 nm on both sides of the transparent resin substrate 10. To do.
[Selection] Figure 2

Description

  The present invention includes a near-infrared cut filter that transmits visible light (wavelength range: 420 nm to 740 nm) out of sunlight (natural light) and cuts near infrared rays (wavelength range: 770 nm to 1800 nm), and a manufacturing method thereof, and the same Regarding glasses.

  Sunburn, stains, buckwheat, etc. are widely recognized as the adverse effects of sunlight contained in sunlight (natural light) on the human body. Numerous research papers have been published and patent applications have been made. Many related products have been commercialized.

On the other hand, until recently, there has been little research on the adverse effects of near-infrared rays contained in natural light on the human body, and the mechanism of the effects on the human body has not been elucidated. It has not been advanced.
Under such circumstances, Patent Document 1 has recently filed a patent application for research results on the influence of near infrared rays on living tissue, and describes the significance of preventing the penetration of near infrared rays into living tissue. .

Although the purpose is completely different from the above-mentioned prevention of near-infrared invasion of living tissue, there are many patent applications related to near-infrared cut filters that cut near-infrared for the purpose of image correction of CCD image sensors, and many are commercialized. ing.
In an image pickup apparatus including a color CCD image sensor such as a video movie camera used for moving image shooting and an electronic still camera used for still image shooting, an infrared cut filter is disposed in front of the color CCD image sensor for image correction. This is different from the sensitivity of the human eye that does not sense light with a wavelength longer than 700 nm, and the sensitivity of the color CCD image sensor is close to 1100 nm, which is the near infrared region within the infrared wavelength range. This is to prevent the black image from being imaged differently from the world seen by people, such as reddish.

  The configuration of the infrared or near-infrared cut filter described above is formed by a multilayer film in which a high refractive index dielectric film and a low refractive index dielectric film are alternately formed on a transparent resin substrate such as resin or glass. As prior art examples, for example, there are proposed one in which a multilayer film is formed on one side of a transparent resin substrate (see Patent Document 2) and one in which a multilayer film is formed on both surfaces of a substrate (see Patent Document 3). These infrared or near-infrared cut filters all have an upper limit wavelength range of infrared rays to be cut from 1000 nm to 1100 nm for image correction of a color CCD image sensor.

  In order to prevent near-infrared rays from entering the eyeball, we also proposed an optical filter that cuts near-infrared rays in the wavelength range of 750 nm to 1800 nm by forming a multilayer film on one side of a transparent resin substrate and glasses equipped with the same. (See Patent Document 4).

WO2009 / 017104 JP 2000-31408 A JP 2003-29027 A JP 2012-208282 A

  The infrared or near-infrared cut filter shown in Patent Documents 2 and 3 described above is mainly used as an image correction filter for a solid-state imaging device such as a color CCD image sensor or CMOS. It is from 1000nm to 1100nm. Therefore, it is not assumed that near-infrared rays having a wavelength range of 1100 nm to 1800 nm that are likely to affect living tissue are cut off.

In the optical filter disclosed in Patent Document 4, a multilayer film made of a dielectric is formed on one surface of a transparent resin substrate. For this reason, the stress when forming the dielectric multilayer film is concentrated on one side of the transparent resin substrate, and the transparent resin substrate may be warped or cracked due to the difference in thermal expansion coefficient, or the dielectric multilayer film may be peeled off. There is a risk.
In addition, when a resin substrate (for example, a polycarbonate substrate) is used as the transparent resin substrate, an ion-assisted vapor deposition method that forms a film with high adhesion even at low temperature film formation is used from the viewpoint of the heat resistance temperature (for example, 120 ° C.) of the resin substrate. However, if the multilayer film is continuously formed, the substrate temperature may gradually rise due to radiant heat and exceed the heat resistant temperature of the resin even if the set temperature is much lower than the heat resistant temperature of the resin substrate, such as 60 ° C. or less. There is. For this reason, work is performed while controlling the temperature of the resin substrate in the process of forming the multilayer film, and if the substrate temperature is likely to exceed the heat resistance temperature, it is necessary to temporarily stop the film forming operation, which may significantly reduce the productivity. is there.

  Thus, in order to achieve the desired optical characteristics using an infrared cut filter having a multilayer film formed on one side of a transparent resin substrate, it is necessary to form a considerable number of multilayer films. There is a need to take an interval for cooling, and the productivity is reduced. In addition, the transparent resin substrate is likely to be deformed or cracked, and the dielectric film also peels off. there were. Further, it can be assumed that the optical characteristics are improved when the number of multilayer films is increased, but the manufacturing process is increased and the product cost is also increased.

  The inventors of the present application pay attention to the near-infrared wavelength region of 770 nm to 1800 nm in the irradiance of sunlight falling on the surface of the earth shown in FIG. 6. There are multiple wavelength ranges that cannot be reached, and the short-wavelength light with a near infrared wavelength range of 770 nm to 1400 nm and the long wavelength light with a wavelength range of 1400 nm to 1800 nm have a higher integrated illuminance than the former. We focused on and proposed the near-infrared cut filter described below.

  The purpose of the present invention is to reduce the stress concentration acting on the resin substrate when forming a film on the transparent resin substrate, and in particular, by blocking near infrared rays in the short wavelength region, stable optical characteristics can be obtained and productivity can be obtained. Another object of the present invention is to provide a near-infrared cut filter that can improve the quality of the filter, a method for manufacturing the same, and eyeglasses that are gentle to the eyes.

In order to achieve the above object, the present invention comprises the following arrangement. A multilayer film in which high-refractive index dielectric films and low-refractive index dielectric films are alternately laminated is formed on both sides of the transparent resin substrate, and allows 90% or more transmission of visible light with a wavelength range of 420 nm to 740 nm. A near-infrared filter for spectacle lenses that cuts near-infrared light having a wavelength range of 770 nm to 1800 nm, and the first multilayer film formed on one surface of the transparent resin substrate has a short wavelength range of 770 nm to 1400 nm The second multilayer film formed on the other surface shields near infrared rays, and shields near infrared rays in a long wavelength region other than the short wavelength region of 1400 nm to 1800 nm to form the first multilayer film The number of laminated films is formed on both surfaces of the transparent resin substrate so as to be larger than the number of dielectric films forming the second multilayer film, and the wavelength region on both surfaces of the transparent resin substrate is 770 nm or more and 1800 nm or less. Near-infrared transmittance of 15% or less of the total amount of sunlight irradiated It cuts so that it may become.

If the near-infrared cut filter is used, the near-infrared light in the short wavelength region is shielded by the first multilayer film formed on one surface of the near-infrared light having a wavelength range of 770 nm to 1800 nm incident on the transparent resin substrate, and the other side. The near-infrared ray in the long wavelength region is shielded by the second multilayer film formed on the surface. As a result, visible light having a wavelength range of 420 nm to 740 nm is transmitted, and the average transmittance of near infrared rays with respect to the integrated irradiation amount of sunlight having a wavelength range of 770 nm to 1800 nm on both surfaces of the transparent resin substrate is 15% or less. Because it cuts, the influence of near infrared rays on the human body and ecosystem can be reduced as much as possible without obstructing the field of view.
In particular, since multilayer films are formed on both sides of the transparent resin substrate, stress concentration is less likely to occur when forming a dielectric film on a transparent resin substrate that is susceptible to heat, and deformation and cracking of the transparent resin substrate occur. In addition, since the number of dielectric films laminated on one side can be reduced, temperature management of the transparent resin substrate is not required, and productivity can be improved.

Also, a high short wavelength region 770nm or 1400nm or less in the near-infrared energy level than out of sunlight that reaches on the earth effectively shielded by the first multilayer film is large number of dielectric films, it than the energy level Dielectric film that can be efficiently blocked by the second multilayer film with a small number of laminated dielectric films, and near infrared light with a low long wavelength range of 1400 nm to 1800 nm can be efficiently formed. The manufacturing cost can be reduced by reducing the number of stacked layers as a whole.

Moreover, it is desirable that a high refractive index dielectric film and a low refractive index dielectric film are alternately formed on both surfaces of the transparent resin substrate at a predetermined film formation temperature lower than the glass transition temperature.
As a result, when the first multilayer film and the second multilayer film are each formed on the transparent resin substrate, the interval between the film formation and the cooling can be shortened, and the productivity can be improved. The resin substrate is not deformed or cracked, and the dielectric film can be prevented from peeling off.

  Further, by adding a pigment to the transparent resin substrate, the number of laminated dielectric films of the first multilayer film and the second multilayer film is reduced as a whole compared to the transparent resin substrate without addition. A film may be formed. In this case, since the transmittance of near infrared rays is reduced by absorption of the dye in addition to the first multilayer film and the second multilayer film, the dielectric forming the first multilayer film and the second multilayer film By further reducing the number of laminated layers, the filter configuration can be simplified and the filter can be efficiently manufactured at low cost. Note that the number of laminated dielectric films may be reduced by either one or both of the first multilayer film and the second multilayer film.

  Further, instead of the transparent resin substrate, a dyed light-transmitting resin substrate that suppresses transmission of visible light having a wavelength range of 420 nm or more and 740 nm or less to less than 90% may be used. In this case, by forming the first multilayer film and the second multilayer film on both surfaces of the sunglasses lens, respectively, in addition to reducing the glare of sunlight, near infrared light with a wavelength range of 770 nm to 1800 nm It is possible to provide a filter that is gentle to the eyeball with reduced transmittance.

  In the above-described near-infrared cut filter manufacturing method in which a multilayer film in which high-refractive index thin films and low-refractive index thin films are alternately laminated on both surfaces of a transparent resin substrate is formed by a vacuum deposition method, A step of rotating the transparent resin substrate held by a tool, and a high refractive index thin film on one surface of the transparent resin substrate at a predetermined film formation temperature lower than a glass transition temperature of the transparent resin substrate in a vacuum state. First vapor deposition step of alternately depositing a plurality of low refractive index thin films and laminating a plurality of layers, and reversing the transparent resin substrate held by the jig, in a vacuum state and from the glass transition temperature of the transparent resin substrate A second vapor deposition step of alternately depositing a plurality of high refractive index thin films and low refractive index thin films on the other surface of the transparent resin substrate at a low predetermined film forming temperature, and laminating a plurality of layers. In the first multilayer film formed on the surface of The second multilayer film formed on the other surface of the transparent resin substrate mainly shields near-infrared light in the long wavelength range of 1400 nm to 1800 nm. And manufacturing a near-infrared cut filter that cuts so that the average transmittance of near-infrared with respect to the cumulative irradiation amount of sunlight having a wavelength range of 770 nm to 1800 nm on both surfaces of the transparent resin substrate is 15% or less. To do.

If the above-mentioned near infrared cut filter manufacturing method is used, the first multilayer film and the second multilayer film are formed on both sides of the transparent resin substrate, so the number of laminated layers is larger than when the multilayer film is formed on one side of the substrate. Near-infrared cut that provides stable optical characteristics because there is no occurrence of defects such as deformation and cracking of the substrate and peeling of the multilayer film. A filter can be provided.
In particular, near-infrared rays with a higher energy level in the short wavelength range of 770 nm to 1400 nm are effectively shielded by the first multilayer film, and the long wavelength range with a lower energy level of 1400 nm to 1800 nm. The structure of the dielectric film can be simplified by efficiently blocking infrared rays with the second multilayer film having a small number of layers.
Also provided is a method for manufacturing a near-infrared cut filter that eliminates the need for temperature control of a transparent resin substrate in a dielectric film deposition operation, and that can improve productivity by reducing the number of laminated dielectric films. be able to.

Further, the spectacles are characterized in that the lens unit is provided with the above-described near-infrared cut filter or a near-infrared cut filter manufactured using the above-described method for manufacturing a near-infrared cut filter.
According to this, since visible light having a wavelength range of 420 nm to 740 nm is transmitted by 90% or more, the first multilayer film provided on one surface of the lens portion without darkening the visibility and reducing the visibility. In the short wavelength region, the second multi-layer film provided on the other side shares the light in the long wavelength region. Is cut so as to be 15% or less with respect to the integrated irradiation amount of sunlight, so that it is possible to provide glasses that are easy on the eyes while preventing near-infrared rays from entering the eyeball as much as possible.

  By using the above-described near-infrared cut filter and its manufacturing method, stable optical characteristics that reduce stress concentration acting on the substrate during film formation on the transparent resin substrate and block near-infrared light in the near-infrared wavelength region can be obtained and It is possible to provide a near-infrared cut filter capable of improving productivity and a method for manufacturing the same. Further, by providing the above-described near infrared cut filter in the lens unit, it is possible to provide glasses that are gentle to the eyes by preventing the near infrared rays from entering the eyeball as much as possible to prevent the temperature from rising.

It is a schematic block diagram of an ion assist vapor deposition apparatus. It is a schematic diagram of a near-infrared cut filter and an explanatory view showing an example of a layer configuration of first and second multilayer films formed on a transparent resin substrate. FIG. 2 is a graph showing the wavelength of light transmitted through the near-infrared cut filter and the double-sided transmittance, a graph showing the transmittance through the first multilayer film, and a graph showing the transmittance through the second multilayer film. FIG. FIG. 4 is an enlarged graph showing the wavelength of light passing through the transparent resin substrate of FIG. 3 and the double-sided transmittance. It is a graph which shows the relationship between the wavelength of the light which permeate | transmits a near-infrared cut off filter, and integrated illumination intensity. It is a graph which shows the relationship between the wavelength of the near infrared rays of the sunlight which reaches | attains the ground surface, and integrated illumination intensity. It is explanatory drawing which shows the schematic diagram of the near-infrared cut filter which concerns on another example, and an example of the layer structure of the 1st, 2nd multilayer film formed in a transparent resin substrate. FIG. 7 is a graph showing the wavelength of light passing through the near-infrared cut filter and the double-sided transmittance, a graph showing the transmittance through the first multilayer film, and a graph showing the transmittance through the second multilayer film. FIG. It is an enlarged graph which shows the wavelength of the light which permeate | transmits the near-infrared cut filter of FIG. 8, and double-sided transmittance | permeability. It is a graph which shows the temperature rise test result with the passage of time of the glass plate directly under the spectacle lens with which the near-infrared cut filter was coated, and the uncoated spectacle lens. It is a graph which shows the temperature rise test result of the lens upper surface and lower surface of the spectacle lens with which the near-infrared cut filter was coated, and an uncoated spectacle lens.

  Hereinafter, an embodiment of a near-infrared cut filter according to the present invention, a method for manufacturing the same, and eyeglasses including the same will be described with reference to the accompanying drawings.

As described above, since sunlight is absorbed by moisture in the atmosphere, it is known that the irradiance (Radiation at Sea Level) of sunlight falling on the ground surface is as shown in FIG. The unit of irradiance is expressed in W / m ^{2. When} attention is paid to the near infrared wavelength range of 770 nm to 1800 nm, there is a portion where the irradiance is almost zero in the vicinity of the wavelength range of 1350 nm to 1450 nm. In addition, there are two groups: short wavelength light with a high integrated illuminance (high energy level) of 770 nm to 1400 nm and long wavelength light with a low integrated illuminance (low energy level) of 1400 nm to 1800 nm. I know.

The near-infrared cut filter according to the present invention is developed and designed in accordance with the shape of the near-infrared irradiance (Radiation at Sea Level) poured into the surface of the solar radiation spectrum. The first multilayer film X formed on one surface of the substrate shares light shielding in a wavelength range of 770 nm to 1400 nm corresponding to short-wavelength light in the near infrared (see FIG. 3B). The light shielding in the wavelength range of 1400 nm to 1800 nm corresponding to the long wavelength light is shared by the second multilayer film Y formed on the other surface of the substrate (see FIG. 3C).
Since the irradiance is almost zero in the wavelength range of 1350 nm to 1450 nm, the transmittance in the wavelength range of 1350 nm to 1400 nm in the first multilayer film X and the wavelength range of 1400 nm to 1450 nm in the second multilayer film Y is low. There is no need to suppress it.
In addition, it is considered that shielding all of the near-infrared wavelength region 770 nm to 1800 nm with only one side of the substrate is a big problem in terms of the performance, quality, cost, etc. of the substrate, and the near infrared is divided into two groups. It would be desirable to share the shading on both sides of the substrate.

As described above, the near-infrared rays falling on the ground surface have an irradiance of 0 W / m ² near the wavelength of 1400 nm. Therefore, even in the case of the near-infrared cut filter of the present invention, the near-infrared wavelength of 1400 nm is used as the boundary. It was decided to share the shading on both sides.
In addition, as shown by a two-dot chain line in FIG. 6, the target near-infrared transmittance is the irradiance on a rainy day when there is no direct light reaching the ground and the load on the eyeball is small and the view is not hindered. However, since it was 15% or less with respect to the irradiance of sunlight on a sunny day, this numerical value was determined as the average transmittance target value of near infrared rays.

  Although there are many unknowns about the effects of near infrared radiation on ecosystems, it can be inferred to some extent from the temperature rise test of a glass plate placed under the lens by irradiating the spectacle lens with artificial sunlight. That is, FIG. 10 shows a spectacle lens with near-infrared cut coating and a spectacle lens without near-infrared cut coating in a solar simulator, and the temperature rise of the glass plate at a position 20 mm below each lens is measured over time. It is the graph which each displayed (for example, measurement for 30 minutes continuously). In FIG. 10, the solid line indicates the temperature change when the near infrared cut coating is present, and the broken line indicates the temperature change when the near infrared cut coating is not present. FIG. 11 is a graph showing the temperature measured on the surface (upper surface) and back surface (lower surface) of the spectacle lens with near infrared cut coating and the spectacle lens without near infrared cut coating in the test of FIG. is there. In FIG. 11, a broken line indicates a temperature change on the upper surface of the lens, and a solid line indicates a temperature change on the lower surface of the lens.

In FIG. 11, since the temperature of the lens itself increases on the front and back surfaces of the spectacle lens, it gradually increases within the irradiation time of sunlight, but with the near infrared cut coating of FIG. In the spectacle lens, the temperature difference between the lens upper surface and the lens lower surface has increased to about 4.5 ° C., which is considered to be an effect of cutting near infrared rays on the lens upper surface.
On the other hand, in the spectacle lens with near-infrared cut coating shown in FIG. 11B, the temperature difference between the upper surface of the lens and the lower surface of the lens is almost 1.6 ° C., and the near-infrared light is transmitted. it is conceivable that.

Moreover, since the distance between the lens and the eyeball is about 20 mm to 30 mm in actual spectacles, the temperature change of the glass plate installed at a position away from the spectacle lens was measured. The results are shown in the graph of FIG. In both cases, the temperature of the glass plate increased from the ambient temperature with the passage of time. However, in the case without the near infrared cut coating, the temperature increase was higher than that with the near infrared cut coating, which was about 10 ° C. It can be seen that the temperature difference between the glass plate receiving the near infrared ray is high and the temperature increase of the glass plate cut from the near infrared ray is suppressed.
From the above, when the ecosystem continues to receive near-infrared rays, the temperature rises according to the accumulated illuminance. For example, in the case of eyeglass lenses, providing a lens that is easy on the eyes for near-infrared cut coating Can be said.

In the present embodiment described below, it is assumed that a spectacle lens is manufactured as an example of a near-infrared cut filter.
With reference to FIG. 1, a schematic configuration of an ion-assisted vapor deposition apparatus that forms a multilayer film on a transparent resin substrate will be described. A multilayer film is required to form a stable thin film with little change in optical characteristics with respect to changes in temperature and humidity. For this reason, the multilayer film formed on both surfaces of the transparent resin substrate forms a thin film by using ion assisted deposition (IAD). For this purpose, ion-assisted vapor deposition is suitably used in order to achieve film formation with high adhesion even at low temperatures without overheating the transparent resin substrate to high temperatures. The ion-assisted deposition apparatus 1 has a configuration as shown in FIG. 1 to form a multilayer film that can obtain uniform and stable optical characteristics.

  As shown in FIG. 1, the ion-assisted vapor deposition apparatus 1 is surrounded by a sealed container of a vacuum chamber 2 and includes an ion source 3 for performing ion assist. In the ion source 3, the ions 4 give kinetic energy to the evaporated substance, and the crystal structure of the deposited film is made amorphous. Amorphization improves the density of the thin film, and it is possible to obtain characteristics in which a wavelength shift hardly occurs even in the outside air.

  In addition, since the ion-assisted deposition apparatus 1 accumulates charges on the thin film by the ions 4 (+) irradiated from the ion source 3, the electrons 6 (-) are irradiated by the neutralizer 5 (Neutrizer) to accumulate the charges. Is preventing.

  The ion-assisted vapor deposition apparatus 1 also includes a first evaporation source 7 that scatters evaporation material having a high refractive index in the vacuum chamber 2 and a second evaporation source 8 that scatters evaporation material having a low refractive index. Openable and closable shutters 7a and 8a are provided above the respective evaporation sources 7 and 8 to promote and block the scattering of the evaporated substance. A dome-shaped substrate dome 9 (jig) is rotatably provided above the shutters 7a and 8a. A plurality of transparent resin substrates 10 are held inside the substrate dome 9. As the transparent resin substrate 10, a resin substrate (for example, a polycarbonate resin substrate) or the like is used. Electron guns 11 are provided in the vicinity of the first and second evaporation sources 7 and 8, respectively, and irradiate an electron beam toward the first and second evaporation sources 7 and 8. As will be described later, the evaporated substance 12 evaporated from the first and second evaporation sources 7 and 8 by irradiating the electron beam can be uniformly deposited on the transparent resin substrate 10 while rotating the substrate dome 9. it can.

In the first vapor deposition step of the ion-assisted vapor deposition apparatus 1, the material of each of the evaporation sources 7 and 8 is evaporated by irradiating the first evaporation source 7 and the second evaporation source 8 with an electron beam 11, thereby By alternately opening the shutters 7a and 8a for a predetermined time, the evaporation substances from the first evaporation source 7 and the second evaporation source 8 can be stacked in a predetermined thickness. For example, titanium dioxide (TiO ₂ ) is supplied to the first evaporation source 7, and silicon dioxide (SiO ₂ ) is supplied to the second evaporation source 8. Incidentally, at the time of deposition of the titanium dioxide (TiO ₂₎ is deposited while supplying oxygen gas.

The vacuum chamber 2 of the ion-assisted vapor deposition apparatus 1 is continuously evacuated in the first vapor deposition step, and titanium dioxide (TiO ₂ ) and silicon dioxide (SiO ₂ ) are alternately laminated. After completion of the first vapor deposition process, the ion assist vapor deposition apparatus 1 once opens the vacuum chamber 2 to the atmosphere, reversely holds the transparent resin substrate 10 held by the substrate dome 9, and starts a similar second vapor deposition process.

Here, an example of the manufacturing method of the near-infrared cut filter using ion-assisted vapor deposition in the vacuum vapor deposition method will be described. The transparent resin substrate 10 is a resin substrate (polycarbonate resin substrate).
A transparent resin substrate 10 is attached to a substrate dome 9 provided in the vacuum chamber 2. Further, pellets of titanium dioxide (solid) (TiO ₂₎ is supplied to the first evaporation source 7,8, silicon dioxide pellets (solid) (SiO ₂₎ is fed to the second evaporation source 8, The vacuum chamber 2 is evacuated to a vacuum state.

When the pressure in the evacuated vacuum chamber 2 becomes 1 × 10 ⁻³ Pa or less, each electron gun 11 irradiates the first evaporation source 7 and the second evaporation source 8 with an electron beam from the electron gun 11. Each of titanium dioxide (TiO ₂ ) and silicon dioxide (SiO ₂ ) is heated and evaporated. Further, the transparent resin substrate 10 held by the substrate dome 9 is rotated in the vacuum chamber 2.

First, titanium dioxide (TiO ₂ ) is formed on one surface of the transparent resin substrate 10. That is, a high refractive index thin film of titanium dioxide (TiO ₂ ) is formed with the shutter 7a opened and the shutter 8a closed. Then, depositing a low-refractive-index film of silicon dioxide, silicon dioxide (SiO ₂₎ remained transparent resin substrate 10 closing the shutter 7a to open the shutter 8a during deposition of (SiO _2). The film formation temperature is a predetermined film formation temperature (for example, 140 ° C.) lower than the glass transition temperature (for example, 145 ° C.) of the transparent resin substrate 10 (polycarbonate resin). The film thickness of each thin film is controlled by closing the shutter when the film thickness measured by the film thickness monitor reaches a predetermined thickness. A plurality of high refractive index thin films (TiO ₂ ) and low refractive index thin films (SiO ₂ ) are alternately stacked. When the first multilayer film reaches a predetermined number, the irradiation of the electron gun 11 is stopped, the evacuation in the vacuum chamber 2 is stopped, and the pressure is returned to the atmospheric pressure (first vapor deposition step).

Next, the transparent resin substrate 10 held on the substrate dome 9 is inverted and held, and the vacuum chamber 2 is evacuated to a vacuum state where the pressure is 1 × 10 ⁻³ Pa or less. The first evaporation source 7 and the second evaporation source 8 are irradiated with an electron beam from each electron gun 11 to heat and evaporate titanium dioxide (TiO ₂ ) and silicon dioxide (SiO ₂ ), respectively. Further, the transparent resin substrate 10 held by the substrate dome 9 is rotated in the vacuum chamber 2.

First, titanium dioxide (TiO ₂ ) is formed on the other surface of the transparent resin substrate 10. That is, a high refractive index thin film of titanium dioxide (TiO ₂ ) is formed with the shutter 7a opened and the shutter 8a closed. Then, depositing a low-refractive-index film of silicon dioxide, silicon dioxide (SiO ₂₎ remained transparent resin substrate 10 closing the shutter 7a to open the shutter 8a during deposition of (SiO _2). The film formation temperature is a predetermined film formation temperature (for example, 140 ° C.) lower than the glass transition temperature (for example, 145 ° C.) of the transparent resin substrate 10 (polycarbonate resin). The film thickness of each thin film is controlled by closing the shutter when the film thickness measured by the film thickness monitor reaches a predetermined thickness. A plurality of high refractive index thin films (TiO ₂ ) and low refractive index thin films (SiO ₂ ) are alternately stacked. When the second multilayer film reaches a predetermined number, irradiation of the electron gun 11 is stopped, evacuation in the vacuum chamber 2 is stopped, and the pressure is returned to atmospheric pressure (second vapor deposition step).

  Through the above steps, the first multilayer film X formed on one surface of the transparent resin substrate 10 shields near infrared rays in the short wavelength region 770 nm to 1400 nm, and the second multilayer film formed on the other surface. In Y, a near-infrared cut filter that blocks near-infrared rays in the long wavelength region of 1450 nm to 1800 nm is formed.

When a resin substrate is used as the transparent resin substrate 10, it is preferable to use titanium dioxide (TiO ₂ ) for film formation of the first layer in consideration of substrate adhesion. Further, when a glass substrate is used as the transparent resin substrate 10, it is preferable to use silicon dioxide (SiO ₂ ) for the film formation of the first layer in consideration of substrate adhesion. However, the present invention is not limited to this mode as long as a cushioning material for improving adhesion is interposed between the transparent resin substrate 10 and the transparent resin substrate 10.
Titanium dioxide (TiO ₂ ) was used as the high refractive index thin film, but niobium pentoxide (Nb ₂ O ₅ ), tantalum pentoxide (TaO ₅ ), zirconium dioxide (ZrO ₂ ), hafnium dioxide (HfO ₂ ), etc. It may be.
Further, although silicon dioxide (SiO ₂ ) is used as the low refractive index thin film, magnesium fluoride (MgF ₂ ) or the like may be used.
Furthermore, although the near-infrared cut filter formed using ion assist vapor deposition was illustrated in the vacuum vapor deposition method, you may use other methods, such as sputtering method, an ion plating method, a plasma assist method.

Here, a configuration example of the near-infrared cut filter will be described with reference to FIG.
FIG. 2A is a schematic cross-sectional view of the transparent resin substrate 10. When the transparent resin substrate 10 is viewed as a lens, the first multilayer film X is formed on the incident surface side, and the second multilayer film Y is formed on the transmission surface side. The first multilayer film X and the second multilayer film Y are both titanium dioxide (TiO ₂ ), which is a high refractive index thin film as the first layer in consideration of adhesion to the transparent resin substrate 10 (polycarbonate resin substrate). The second layer is made of silicon dioxide (SiO ₂ ), which is a low refractive index thin film, and is laminated alternately.

FIG. 2B illustrates the number of stacked first multilayer film X and second multilayer film Y. In the first multilayer film X, a high refractive index thin film (TiO ₂ ) and a low refractive index thin film (SiO ₂ ) are alternately laminated to form a total of 26 layers. In addition, the second multilayer film Y is formed by alternately laminating high refractive index thin films (TiO ₂ ) and low refractive index thin films (SiO ₂ ), for a total of 19 layers. Since the light transmittance of the near-infrared cut filter is determined by the product of the refractive index and the film thickness of the transparent thin film, the refractive index, the film thickness, and the number of layers are designed so as to realize the desired near-infrared transmittance. Generally, the film thickness is designed around ¼ of the wavelength so that the reflectance or transmittance of the wavelength is maximized.

  In this embodiment, in forming the first multilayer film X that cuts near infrared rays in the short wavelength range 770 nm to 1400 nm and the second multilayer film Y that cuts near infrared rays in the long wavelength range 1450 nm to 1800 nm, The number of laminated dielectric films forming X is formed on both surfaces of the transparent resin substrate 10 so as to be larger than the number of laminated dielectric films forming the second multilayer film Y. This is because in the near-infrared wavelength range of 770 nm to 1800 nm of the irradiance of sunlight falling on the ground surface shown in FIG. 6, there are multiple wavelength ranges where the near-infrared light is absorbed by water vapor in the atmosphere and does not reach the ground. The reason is that the near-infrared integrated illuminance is larger than the long wavelength light in the wavelength range of 1400 nm to 1800 nm than the short wavelength light in the wavelength range of 770 nm to 1400 nm.

  This effectively shields near-infrared rays in the short wavelength range of 770 nm to 1400 nm, which has a higher energy level, from sunlight reaching the ground by the first multilayer film X having a large number of dielectric films, and further reduces the energy level. Can be efficiently blocked by the second multilayer film Y having a small number of laminated dielectric films, and the dielectric film formed on both surfaces of the transparent resin substrate 10 can be efficiently blocked. Manufacturing cost can be reduced by reducing the number of laminated body films as a whole.

  3 shows the double-sided transmittance with respect to the wavelength of light using the near-infrared cut filter having the first multilayer film X and the second multilayer film Y shown in FIGS. 2A and 2B, and the first multilayer film. The transmittance with respect to the wavelength of light of X and the transmittance with respect to the wavelength of light of the second multilayer film Y are illustrated. FIG. 4 is an enlarged graph showing the double-sided transmittance with respect to the near infrared wavelength.

First, the transmittance when natural light is transmitted through the first multilayer film X formed on the incident side in FIG. 2A is indicated by a thick broken line in FIG. As can be seen from FIG. 3, the first multilayer film X shields near-infrared rays in the short wavelength region of 770 nm to 1400 nm to approximately 15% or less. Further, the transmittance when natural light is transmitted through the second multilayer film Y formed on the emission side in FIG. 2A is indicated by a thin broken line in FIG. According to FIG. 3, it can be seen that the second multilayer film Y shields near infrared rays in the long wavelength region of 1400 nm to 1800 nm to approximately 30% or less.
That is, the first multilayer film X and the second multilayer film Y share near-infrared rays in different wavelength ranges and shield them, thereby providing a double-sided transmittance and a wavelength range of 770 nm to 1800 nm as shown in FIG. The near-infrared cut filter that cuts the near-infrared rays to approximately 30% or less is formed.

  As a result, as shown in a graph showing the relationship between the wavelength of light transmitted through the near-infrared cut filter of FIG. 5 and the integrated illuminance, sunlight having a wavelength range of 770 nm to 1800 nm on both surfaces of the transparent resin substrate 10 is shown. It was possible to cut so that the average transmittance of near-infrared with respect to the integrated irradiation amount of 15% or less. The reason why the average near-infrared transmittance is set to 15% or less is that, as explained in FIG. 6, there is no direct light reaching the ground, so there is less irradiance on a rainy day when the load on the eyeball is small and the view is not obstructed. Since it is 15% or less with respect to the irradiance of sunlight on a sunny day, this numerical value was determined as the average transmittance of near infrared rays. Thereby, the influence which near infrared rays have on a human body and an ecosystem can be reduced as much as possible, without disturbing a visual field.

Infrared cut filters for sensitivity correction of solid-state image sensors such as CCD and CMOS can cut near infrared rays with an upper limit wavelength range of 1000 nm to 1100 nm by forming a multilayer film of about 30 layers on one side. However, in order to cut a wide range of near infrared rays of 770 nm to 1800 nm, when a multilayer film is formed only on one side, a multilayer film exceeding 80 layers is required. For this reason, the influence which the dispersion | variation in film thickness at the time of film-forming has on an optical characteristic becomes large.
On the other hand, as shown in the present embodiment, the first multilayer film X and the second multilayer film Y are formed on both surfaces of the transparent resin substrate 10 to shield near infrared rays in different wavelength ranges, The total number of layers can be reduced and the variation in film thickness is reduced, so that the optical characteristics are stabilized.

  Next, a configuration example of a near-infrared cut filter according to another example will be described with reference to FIG. In this embodiment, the first multilayer film X and the second multilayer film Y are added to the transparent resin substrate 10 by adding a pigment (for example, a blue colorant; a bluing agent) as compared with the additive-free transparent resin substrate 10. An example in which the number of stacked 'dielectric films is reduced is shown. FIG. 7A is a schematic cross-sectional view of the transparent resin substrate 10. When the transparent resin substrate 10 is viewed as a lens, the first multilayer film X is formed on the incident surface side, and the second multilayer film Y ′ is formed on the transmission surface side. The first multilayer film X and the second multilayer film Y ′ are both titanium dioxide (TiO2), which is a high refractive index thin film as the first layer in consideration of adhesion to the transparent resin substrate 10 (polycarbonate resin substrate). The second layer is made of silicon dioxide (SiO2), which is a low refractive index thin film, and is laminated alternately.

  FIG. 7B illustrates the number of stacked first multilayer film X and second multilayer film Y ′. In the first multilayer film X, a high refractive index thin film (TiO 2) and a low refractive index thin film (SiO 2) are alternately laminated to form a total of 26 layers. In addition, the second multilayer film Y ′ has a high refractive index thin film (TiO 2) and a low refractive index thin film (SiO 2) alternately stacked to form a total of 13 layers. The first multilayer film X has the same number of layers as that in FIG. 2B, but it is needless to say that the number can be reduced.

  FIG. 8 shows the double-sided transmittance with respect to the wavelength of light of the near-infrared cut filter having the first multilayer film X and the second multilayer film Y ′ and the dye-containing transparent resin substrate 10 shown in FIGS. The transmittance of the first multilayer film X with respect to the wavelength of light, the transmittance of the second multilayer film Y ′ with respect to the wavelength of light, and the transmittance of the transparent resin substrate 10 with respect to the wavelength of light are illustrated. FIG. 9 shows an enlarged graph of the double-sided transmittance with respect to the light wavelength of the near-infrared cut filter.

First, the transmittance when natural light is transmitted through the first multilayer film X formed on the incident side in FIG. 7A is indicated by a one-dot chain line in FIG. According to FIG. 8, it can be seen that the first multilayer film X shields near infrared rays in the short wavelength region of 770 nm to 1400 nm to approximately 15% or less. Further, the transmittance when natural light is transmitted through the second multilayer film Y formed on the emission side in FIG. 7A is indicated by a broken line in FIG. According to FIG. 8, the second multilayer film Y shields the near-infrared rays in the long wavelength range of 1400 nm to 1800 nm from 30% but does not exceed 35% due to the decrease in the number of laminated multilayer films. I understand. Further, according to FIG. 8, the dye-containing resin substrate transmits 60% or more of near infrared light in the short wavelength region 770 nm to 1400 nm, but the wavelength that cuts near infrared light in the long wavelength region 1400 nm to 1800 nm to 30% or less. It can be seen that there is an area. Further, the first multilayer film X also transmits near infrared rays in the long wavelength region of 1400 nm to 1800 nm by 60% or more, but there is a relatively low region that is partially close to 60%.
That is, the first multilayer film X shields the near-infrared light in the short wavelength region and the second multilayer film Y shares the near-infrared light in the long wavelength region. By combining the shielding of near-infrared light in the region, a near-infrared cut filter that cuts near-infrared light in the wavelength range of 770 nm to 1800 nm to approximately 30% or less with double-sided transmittance as shown in FIG. 9 is formed. .

As a result, as shown in a graph showing the relationship between the wavelength of light transmitted through the near-infrared cut filter of FIG. 5 and the integrated illuminance, sunlight having a wavelength range of 770 nm to 1800 nm on both surfaces of the transparent resin substrate 10 is shown. It was possible to cut so that the average transmittance of near-infrared with respect to the integrated irradiation amount of 15% or less.
Thus, by adding the pigment to the transparent resin substrate 10, the total number of the dielectric films of the first multilayer film X and the second multilayer film Y ′ is reduced as a whole compared with the additive-free transparent resin substrate. Even if the film is formed, the same optical characteristics can be realized. That is, the near-infrared transmittance decreases due to the absorption of the dye in addition to the first multilayer film X and the second multilayer film Y ′, so the first multilayer film X and the second multilayer film Y ′ are formed. Further, the number of laminated dielectric films can be further reduced, the filter configuration can be simplified, and the filter can be efficiently manufactured at low cost.

  In the above embodiment, the transparent resin substrate 10 (polycarbonate resin substrate) constituting the near-infrared cut filter is used. Instead, transmission of visible light having a wavelength range of 420 nm to 740 nm is suppressed to less than 90%. You may form the near-infrared cut filter mentioned above on both surfaces using the colored transparent resin substrate which carries out. In this case, by forming the first multilayer film X and the second multilayer film Y on both surfaces of the colored color lens, respectively, in addition to suppressing the transmission of visible light and reducing the glare of sunlight, A filter that is gentle to the eyeball can be provided by cutting so that the average transmittance of near-infrared rays in the wavelength range of 770 nm to 1800 nm is 15% or less.

  If the near-infrared cut filter is used, the near-infrared light in the short wavelength region is shielded by the first multilayer film X formed on one surface of the near-infrared light having a wavelength range of 770 nm to 1800 nm incident on the transparent resin substrate 10. The second multilayer film Y formed on the other surface shields near infrared rays in the long wavelength region. As a result, visible light having a wavelength range of 420 nm to 740 nm is transmitted, and near infrared light having a wavelength range of 770 nm to 1800 nm is cut so that the average transmittance is 15% or less with respect to the integrated irradiation amount of sunlight. The effects of near infrared rays on human bodies and ecosystems can be reduced as much as possible.

  In addition, the dielectric film forming the first multilayer film X is formed on both surfaces of the transparent resin substrate 10 so as to be larger than the number of dielectric films forming the second multilayer film Y. It is desirable. This effectively shields near-infrared rays in the short wavelength range of 770 nm to 1400 nm, which has a higher energy level, from sunlight reaching the ground by the first multilayer film X having a large number of dielectric films, and further reduces the energy level. Can be efficiently blocked by the second multilayer film Y having a small number of laminated dielectric films, and the dielectric film formed on both surfaces of the transparent resin substrate 10 can be efficiently blocked. Manufacturing cost can be reduced by reducing the number of laminated body films as a whole.

In particular, since the multilayer films X and Y are respectively formed on both surfaces of the transparent resin substrate 10, stress concentration is difficult to occur when forming a dielectric film on the transparent resin substrate 10, and deformation and cracking of the substrate can be suppressed. In addition, since the number of dielectric films laminated on one side can be reduced, temperature management of the transparent resin substrate 10 is not required, and productivity can be improved.
Also, the first multilayer film X on the incident surface side functions as a reflection mirror for near-infrared short wavelength light 770 nm to 1400 nm, and the second multilayer film Y on the transmission surface side for near-infrared long wavelength light 1400 nm to 1800 nm. It can function as a reflection mirror, and can secure high transparency of visible light having a wavelength range of 420 nm to 740 nm while shielding near infrared rays. By providing mirrors on both sides of the substrate, the temperature rise of the transparent resin substrate 10 itself can be suppressed, and deformation of the substrate and peeling of the multilayer film can be suppressed.
Conversely, near-infrared long-wavelength light 1400 nm to 1800 nm is shielded by the first multilayer film X on the incident surface side, and near-infrared short-wavelength light 770 nm to 1400 nm is transmitted by the second multilayer film on the transmission surface side. Can also be shielded from light.

Further, according to the graph of FIG. 3, in addition to effectively cutting near infrared rays having a wavelength range of 770 nm to 1800 nm incident on the transparent resin substrate 10, UV light (ultraviolet rays) having a wavelength range of 200 nm to 400 nm is also effective. Can be blocked.
Therefore, if the transparent resin substrate 10 to which the near-infrared cut filter is applied is used for the lens portion for spectacles, it is possible to provide spectacles that are extremely eye-friendly. Or if a near-infrared cut filter is used as a light-shielding sheet, it can be used to protect not only human bodies but also ecosystems (animals and plants).

  DESCRIPTION OF SYMBOLS 1 Ion-assisted vapor deposition apparatus 2 Vacuum chamber 3 Ion source 4 Ion 5 Neutralizer 6 Electron 7 First evaporation source 7a, 8a Shutter 8 Second evaporation source 9 Substrate dome 10 Transparent resin substrate 11 Electron gun 12 Evaporating substance X first multilayer film Y, Y ′ second multilayer film

Claims (5)

A multilayer film in which high-refractive index dielectric films and low-refractive index dielectric films are alternately laminated is formed on both sides of the transparent resin substrate, and allows 90% or more transmission of visible light with a wavelength range of 420 nm to 740 nm. A near-infrared filter for spectacle lenses that cuts near-infrared light in the wavelength range of 770 nm to 1800 nm,
The first multilayer film formed on one surface of the transparent resin substrate blocks near infrared rays in the short wavelength region of 770 nm to 1400 nm , and the second multilayer film formed on the other surface other than the short wavelength region. The number of dielectric films that form the first multilayer film is greater than the number of dielectric films that form the second multilayer film by shielding near infrared rays in the long wavelength region of 1400 nm to 1800 nm. In this way, the film is formed on both surfaces of the transparent resin substrate, and the both sides of the transparent resin substrate are cut so that the near-infrared average transmittance with respect to the integrated irradiation amount of sunlight having a wavelength range of 770 nm to 1800 nm is 15% or less. A near-infrared cut filter characterized by that. By adding a pigment to the transparent resin substrate, the number of laminated dielectric films of the first multilayer film and the second multilayer film was reduced as a whole compared to the transparent resin substrate without addition. The near-infrared cut filter according to claim 1. Instead of the transparent resin substrate,請 Motomeko 1 or claim 2 NIR described using an optically transparent resin substrate wavelength region is colored to suppress the transmission of the following visible light 420nm or 740nm lower than 90% Cut filter. A method for producing a near-infrared cut filter as described above, wherein a multilayer film in which a high refractive index thin film and a low refractive index thin film are alternately laminated on both sides of a transparent resin substrate is formed by vacuum deposition,
A step of rotating the transparent resin substrate held by a jig in a vacuum vessel;
A plurality of high refractive index thin films and low refractive index thin films are alternately deposited on one surface of the transparent resin substrate at a predetermined film formation temperature lower than the glass transition temperature of the transparent resin substrate in a vacuum state. A first vapor deposition step;
The transparent resin substrate held by the jig is inverted, and a high refractive index thin film and a low refractive index film are placed on the other surface of the transparent resin substrate at a predetermined film formation temperature lower than the glass transition temperature of the transparent resin substrate in a vacuum state. A second vapor deposition step of alternately stacking a plurality of refractive index thin films, and
The first multilayer film formed on one surface of the transparent resin substrate mainly shields near-infrared light in the short wavelength region of 770 nm to 1400 nm and is formed on the other surface of the transparent resin substrate. The film mainly shields near-infrared light in the long wavelength range from 1400 nm to 1800 nm, so that the average transmittance of near-infrared relative to the cumulative irradiation amount of sunlight with wavelength range from 770 nm to 1800 nm on both sides of the transparent resin substrate is 15%. The manufacturing method of the near-infrared cut filter characterized by manufacturing the near-infrared cut filter cut so that it may become the following. A near-infrared cut filter manufactured by using the near-infrared cut filter according to claim 1 or the manufacturing method according to claim 4 in a lens part.

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