JP7332359B2 - Anti-reflective coating - Google Patents

Description

The present invention relates to an anti-reflection coating applied to optical members such as lenses, prisms, filters, optical fiber end faces, astronomical observations, laser processing machines, and optical elements mounted on optical equipment, and to optical members and optical equipment using anti-reflection coatings. More particularly, the present invention relates to an anti-reflection coating capable of coping with a wavelength region that can be perceived as a color by the human eye, and an optical member and an optical device using the anti-reflection coating.

In general, various types of lenses have been proposed for the lenses widely used in optical equipment such as cameras for taking still images and moving images. lenses are mounted side by side on the lens barrel.

In addition, the antireflection film is formed by stacking multiple thin film layers with different refractive indices on the surface of the lens. By suppressing it, it is possible to suppress factors that degrade optical characteristics, such as flare and ghost, which are likely to occur when shooting with backlight or semi-backlight, and improve product performance.
In addition, by suppressing the reflectance of incident light, attenuation of incident light can be suppressed particularly when a large number of lenses are used side by side.

For example, in Patent Document 1, optical base layers 1 to 14 are formed on the surface of an optical base material having a refractive index of 1.43 or more and 2.01 or less at the d-line (wavelength of 587.56 nm) of a He light source. Antireflection films are known which are laminated in order from the material side.

In the antireflection film described in Patent Document 1, the first layer, the third layer, the fifth layer, the seventh layer, the ninth layer, the eleventh layer and the thirteenth layer have a refractive index of 2.201 or more at the d-line. A high refractive index layer formed of a high refractive index material of 2.7 or less, and the second layer, the fourth layer, the sixth layer, the eighth layer, the tenth layer, and the twelfth layer have a refractive index of 1 at the d-line 051 or more and 1.7 or less, and the 14th layer is formed of a low refractive index material whose refractive index at the d-line is 1.37 or more and 1.44 or less. By forming the refractive index layer, the reflectance in the wavelength band of 330 nm from 390 nm to 720 nm can be reduced to 0.1% or less with respect to vertically incident light, and the product performance can be improved. be.

JP 2015-22187 A

However, the antireflection film known in Patent Document 1 still has room for improvement.
That is, the antireflection film known in Patent Document 1 achieves a reflectance of 0.1% or less in the range from 390 nm to 720 nm, which is the majority of the general visible light wavelength region. According to the definition of JIS Z 8120, the wavelength range that can be perceived as color has a short wavelength limit of approximately 360 nm to 400 nm and a long wavelength limit of approximately 760 nm to 830 nm. In the large visible light wavelength range, there is a possibility that the incident light cannot be sufficiently transmitted.

The present invention is intended to solve the above problems, with a simple structure, the reflectance is 0.1% or less in the visible light wavelength range wider than 330 nm, and the optical characteristics such as flare and ghost are degraded. An object of the present invention is to provide an antireflection film capable of suppressing factors, and an optical member and an optical device using the antireflection film.

As a result of intensive studies, the inventors of the present invention have found that, for example, when an antireflection film is laminated on an optical substrate and the optical substrate side is formed of 14 layers with the first layer being the first layer, the 14th layer has the lowest refractive index, Each of the first layer, the third layer, the fifth layer, the seventh layer, the ninth layer, the eleventh layer and the thirteenth layer has a higher refractive index than at least the adjacent layers, and the second layer, the fourth layer, the By setting the refractive index in the wavelength region used by any one of the sixth layer, the eighth layer, the tenth layer, and the twelfth layer to be 1.4 or more, the wavelength band in the visible light wavelength region is It was found that the reflectance can be reduced to 0.1% or less even in a wide range exceeding 330 nm.

That is, the antireflection film of the present invention is an antireflection film formed by laminating a plurality of layers having different refractive indices on an optical substrate, and the antireflection film is the layer farthest from the optical substrate. at least a certain outermost layer and a plurality of first-type intermediate layers and a plurality of second-type intermediate layers formed between the outermost layer and the optical substrate; The seed intermediate layers are each formed of at least one or more refractive index materials, the layer adjacent to the outermost layer is the second intermediate layer, and the antireflection film comprises the first intermediate layer and the second-type intermediate layers are alternately laminated, and each of the first-type intermediate layers is formed to have a lower refractive index than the second-type intermediate layer adjacent to the first-type intermediate layer. At least one of the first type intermediate layers sandwiched between the seed intermediate layers is a specific intermediate layer formed to have a refractive index of 1.75 or more and less than 2.7 in the wavelength range used , The type 1 intermediate layer excluding the specific intermediate layer has a refractive index of 1.4 or more and less than 1.75 in the wavelength range used, and the layer adjacent to the optical substrate is made of Ta 2 _O 5 _. By doing so, the above problems are solved.

According to the antireflection film of claim 1, the antireflection film includes an outermost layer, and a plurality of first-type intermediate layers and a plurality of second-type intermediate layers formed between the outermost layer and the optical substrate. , the layer adjacent to the outermost layer is a type 2 intermediate layer, the antireflection film is formed by alternately laminating the type 1 intermediate layer and the type 2 intermediate layer, and each type 1 intermediate layer At least one of the first-type intermediate layers sandwiched between the second-type intermediate layers formed to have a lower refractive index than the second-type intermediate layers adjacent to the first-type intermediate layers has a refractive index in the wavelength range used. The specific intermediate layer is formed to have a refractive index of 1.75 or more and less than 2.7 , and the type 1 intermediate layer excluding the specific intermediate layer has a refractive index of 1.4 or more and less than 1.75 in the wavelength region used. Since the layer adjacent to the optical substrate is composed of Ta ₂ O ₅ , the reflectance can be made 0.1% or less in a range wider than 330 nm in the visible light wavelength region, and the incident light can be sufficiently reflected. can pass through.
In addition, by adjusting and forming the outermost layer, the type 1 intermediate layer, and the type 2 intermediate layer to thicknesses that can be stably formed, the anti-reflection coating can be applied to optical surfaces while maintaining high productivity. It can also be formed on a substrate.

According to the configuration of claim 2, the specific intermediate layer is formed at least in the layer adjacent to the second type intermediate layer adjacent to the outermost layer, so that in the visible light wavelength region, The reflectance can be stably set to 0.1% or less, and the incident light can be sufficiently transmitted.
According to the configuration of claim 3, the refractive index of the outermost layer in the wavelength range used is 1.3 or more and 1.41 or less, so in the visible light wavelength range, the reflectance in a range wider than 330 nm can be more stably reduced to 0.1% or less, and sufficient incident light can be transmitted.

According to the configuration of claim 4 , the refractive index of the type 2 intermediate layer in the wavelength range used is 2.7 or less. It can be made 0.1% or less more stably, and the incident light can be sufficiently transmitted.

According to the configuration of claim 6, the refractive index of the optical substrate is 1.4 or more and 2.3 or less, so that the reflectance is further stabilized in a range wider than 330 nm in the visible light wavelength region. It can be made 0.1% or less, and sufficient incident light can be transmitted.
According to the configuration of claim 7, the antireflection film is composed of 14 layers, and when the optical substrate side when laminated on the optical substrate is the first layer, the physical thickness of the first layer is 2 nm. The physical film thickness of the second layer is 20 nm or more and 70 nm or less, the physical film thickness of the third layer is 20 nm or more and 60 nm or less, and the physical film thickness of the fourth layer is 2 nm or more and 20 nm or less. The physical thickness of the fifth layer is 60 nm or more and 130 nm or less, the physical thickness of the sixth layer is 10 nm or more and 45 nm or less, and the physical thickness of the seventh layer is 5 nm or more and 40 nm or less. The physical film thickness of the eighth layer is 70 nm or more and 150 nm or less, the physical film thickness of the ninth layer is 3 nm or more and 60 nm or less, the physical film thickness of the tenth layer is 10 nm or more and 50 nm or less, The 11th layer has a physical thickness of 20 nm or more and 90 nm or less, the 12th layer has a physical thickness of 10 nm or more and 60 nm or less, the 13th layer has a physical thickness of 2 nm or more and 30 nm or less, and the 14th layer has a physical thickness of 2 nm or more and 30 nm or less. Since the physical thickness of the layer is 40 nm or more and 200 nm or less, the thickness of each layer of the antireflection film is reliably maintained at a thickness that can be stably formed, and is wider than 330 nm in the visible light wavelength region. The reflectance can be stably set to 0.1% or less within a range, and the incident light can be sufficiently transmitted.

1 is a schematic diagram of an antireflection film 100 according to one embodiment (Embodiment 1) of the present invention. FIG. 1 is a table showing the configuration of an antireflection film 100 according to one embodiment (Embodiment 1) of the present invention; 4 is a graph showing the reflectance of the antireflection film 100 according to one embodiment (Embodiment 1) of the present invention for incident light in each visible light wavelength range. 4 is a table showing the configuration of an antireflection film 130 according to another embodiment (embodiment 2) of the present invention; 5 is a graph showing the reflectance of the anti-reflection film 130 according to another embodiment (Embodiment 2) of the present invention for incident light in each visible light wavelength range. 4 is a table showing the configuration of an antireflection film 160 according to another embodiment (Embodiment 3) of the present invention; 5 is a graph showing the reflectance of the antireflection film 160 according to another embodiment (Embodiment 3) of the present invention for incident light in each visible light wavelength range. 4 is a table showing the configuration of an antireflection film 200 according to a reference example ( reference form 1 ) of the present invention; 4 is a graph showing the reflectance of the antireflection film 200 according to the reference example ( reference form 1 ) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 230 according to another embodiment (Embodiment 5) of the present invention; 9 is a graph showing the reflectance of the antireflection film 230 according to another embodiment (embodiment 5) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 260 according to another embodiment (Embodiment 6) of the present invention; 9 is a graph showing the reflectance of the antireflection film 260 according to another embodiment (embodiment 6) of the present invention for incident light in each visible light wavelength range. 4 is a table showing the configuration of an antireflection film 300 according to a reference example ( reference form 2 ) of the present invention; 4 is a graph showing the reflectance of the antireflection film 300 according to the reference example ( reference form 2 ) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 330 according to another embodiment (Embodiment 8) of the present invention; 9 is a graph showing the reflectance of the antireflection film 330 according to another embodiment (Embodiment 8) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 360 according to another embodiment (Embodiment 9) of the present invention; 10 is a graph showing the reflectance of the antireflection film 360 according to another embodiment (ninth embodiment) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 400 according to another embodiment (embodiment 10) of the present invention; 10 is a graph showing the reflectance of the antireflection film 400 according to another embodiment (embodiment 10) of the present invention for incident light in each visible light wavelength range. FIG. 11 is a table showing the configuration of an antireflection film 430 according to another embodiment (embodiment 11) of the present invention; FIG. 10 is a graph showing the reflectance of the antireflection film 430 according to another embodiment (embodiment 11) of the present invention for incident light in each visible light wavelength range. 10 is a table showing the configuration of an antireflection film 460 according to another embodiment (embodiment 12) of the present invention; 10 is a graph showing the reflectance of the antireflection film 460 according to another embodiment (embodiment 12) of the present invention for incident light in each visible light wavelength range. 13 is a table showing the configuration of an antireflection film 500 according to another embodiment (embodiment 13) of the present invention; 10 is a graph showing the reflectance of the antireflection film 500 according to another embodiment (Embodiment 13) of the present invention for incident light in each visible light wavelength range. FIG. 10 is a table showing the configuration of an antireflection film 530 according to another embodiment (embodiment 14) of the present invention; FIG. 10 is a graph showing the reflectance of the antireflection film 530 according to another embodiment (Embodiment 14) of the present invention for incident light in each visible light wavelength range.

An antireflection film 100 according to one embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the antireflection film 100 includes layers having different refractive indices on an optical substrate L, a first layer 101, a second layer 102, a third layer 103, a fourth layer 104, a fifth layer 105, a Sixth layer 106, seventh layer 107, eighth layer 108, ninth layer 109, tenth layer 110, eleventh layer 111, twelfth layer 112, thirteenth layer 113 and fourteenth layer 114, a total of 14 layers are laminated. Each layer is roughly classified into an outermost layer, a first type intermediate layer, and a second type intermediate layer.
The outermost layer is the fourteenth layer 114 , which has the lowest refractive index in the antireflection film 100 .

The first type intermediate layers are the second layer 102, the fourth layer 104, the sixth layer 106, the eighth layer 108, the tenth layer 110, and the twelfth layer 112, and are formed to have a higher refractive index than the outermost layer. there is
The second type intermediate layers are the first layer 101, the third layer 103, the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113. It is formed to have a refractive index equal to or higher than the refractive index.

At least one of the type 1 intermediate layers is a specific intermediate layer formed to have a refractive index of 1.41 or more in the wavelength range used.
The first-type intermediate layer and the second-type intermediate layer are laminated so that the refractive index of the adjacent layers alternately changes.
Thereby, the reflectance of incident light passing through the antireflection film 100 can be sufficiently reduced.
In addition, factors such as flare and ghost that degrade optical characteristics can be suppressed.

The preferable range of the refractive index of the outermost layer is 1.3 or more and 1.41 or less, and the preferable range of the refractive index of the type 1 intermediate layer excluding the specific intermediate layer is 1.4 or more and 1.75. A preferable range of the refractive index of the type 2 intermediate layer is 1.75 or more and 2.7 or less.
In addition, the preferable range of the physical thickness of each layer forming the antireflection film 100 is that the physical thickness of the first layer 101 is 2 nm or more and 30 nm or less, and the physical thickness of the second layer 102 is 20 nm or more and 70 nm. The physical thickness of the third layer 103 is 20 nm or more and 60 nm or less, the physical thickness of the fourth layer 104 is 2 nm or more and 20 nm or less, and the physical thickness of the fifth layer 105 is 60 nm or more. The physical film thickness of the sixth layer 106 is 10 nm or more and 45 nm or less, the physical film thickness of the seventh layer 107 is 5 nm or more and 40 nm or less, and the physical film thickness of the eighth layer 108 is 70 nm. The physical film thickness of the ninth layer 109 is 3 nm or more and 60 nm or less, the physical film thickness of the tenth layer 110 is 10 nm or more and 50 nm or less, and the physical film thickness of the eleventh layer 111 is The physical film thickness of the 12th layer 112 is 20 nm or more and 90 nm or less, the physical film thickness of the 13th layer 113 is 2 nm or more and 30 nm or less, and the physical film thickness of the 14th layer 114 is , 40 nm or more and 200 nm or less.

By defining the refractive index and physical thickness of each layer of the antireflection film 100 in this manner, it is possible to provide an antireflection film that can sufficiently reduce the reflectance of incident light while maintaining moldability.
The processing method of each layer of the antireflection film is not particularly limited, and for example, vacuum deposition, various sputtering deposition, ion assist method, and ion plating method may be used.

Next, as Embodiment 1, simulation conditions and results regarding the antireflection film 100 according to one embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG.
As shown in FIGS. 1 and 2, the antireflection film 100 has 14 layers laminated on an optical substrate L formed of S-LAH55 (manufactured by Ohara Co., Ltd.), and each layer is a first type intermediate layer. The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical thickness of each layer are as shown in FIG.
The _refractive index of each _layer and the _optical substrate L is for _a light source with a typical _wavelength . and S-LAH55 indicates the refractive index for a light source with a wavelength of 546 nm.

FIG. 3 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 100 of Embodiment 1 configured as described above is irradiated with incident light.
In this simulation, in consideration of the error that occurs during the actual formation of the antireflection film, the portion where the reflectance obtained in the simulation is less than 0.11 is assumed to be 0.1 or less. .
In addition, it is assumed that incident light enters the surface of the antireflection film 100 perpendicularly, and the atmospheric gas around the antireflection film 100 and the optical substrate L is air.
As shown in FIG. 3, the antireflection film 100 of Embodiment 1 has a minimum wavelength of 409 nm (reflectance of 0.0906) at which the reflectance is 0.1 or less, and a maximum wavelength of 770 nm (reflectance of 0.1 or less). Since the reflectance is 0.1055), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 361 nm.
That is, the antireflection film 100 of Embodiment 1 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Hereinafter, a part of the description of the contents common to the first embodiment will be omitted.

Next, as Embodiment 2, simulation conditions and results regarding an antireflection film 130 according to another embodiment of the present invention will be described with reference to FIGS. 1, 4, and 5. FIG.
As shown in FIGS. 1 and 4, the antireflection film 130 has 14 layers laminated on the optical substrate L formed of S-TIH53 (manufactured by Ohara Co., Ltd.). The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical thickness of each layer are as shown in FIG.
The refractive index of S-TIH53 is for a light source with a wavelength of 546 nm.

FIG. 5 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 130 of Embodiment 2 configured as described above is irradiated with incident light.
As shown in FIG. 5, the antireflection film 130 of Embodiment 2 has a minimum wavelength of 409 nm (reflectance of 0.0913) at which the reflectance is 0.1 or less, and a maximum wavelength of 770 nm (reflectance of 0.1 or less). Since the reflectance is 0.1056), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 361 nm.
That is, the antireflection film 130 of Embodiment 2 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 3, simulation conditions and results regarding an antireflection film 160 according to another embodiment of the present invention will be described with reference to FIGS. 1, 6, and 7. FIG.
As shown in FIGS. 1 and 6, the antireflection film 160 has 14 layers laminated on the optical substrate L formed of S-NPH2 (manufactured by Ohara Co., Ltd.), and each layer is a first type intermediate layer. The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-NPH2 is for a light source with a wavelength of 546 nm.

FIG. 7 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 160 of Embodiment 3 configured as described above is irradiated with incident light.
As shown in FIG. 7, the antireflection film 160 of Embodiment 3 has a minimum wavelength of 408 nm (reflectance of 0.1069) at which the reflectance is 0.1 or less, and a maximum wavelength of 770 nm (reflectance of 0.1 or less). Since the reflectance is 0.1058), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 362 nm.
That is, the antireflection film 160 of Embodiment 3 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as reference form 1 , simulation conditions and results regarding the antireflection film 200 of the reference example of the present invention will be described with reference to FIGS. 1, 8, and 9. FIG.
As shown in FIGS. 1 and 8, the antireflection film 200 has 14 layers laminated on the optical substrate L formed of S-LAH79 (manufactured by Ohara Co., Ltd.), and each layer is a first type intermediate layer. The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the _10th layer 110 are made of _SiO2 , the 12th layer 112 which is a specific intermediate layer is made of _Ta2O5 , and the 2nd type intermediate layer is made of SiO2. The first layer 101, the third layer 103, the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113 are made of _TiO2 , and the fourteenth layer 114, which is the outermost layer, is made of _MgF2. It is
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-LAH79 is for a light source with a wavelength of 546 nm.

FIG. 9 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 200 of Reference Form 1 configured as described above is irradiated with incident light.
As shown in FIG. 9, the antireflection film 200 of Reference Form 1 has a minimum wavelength of 408 nm (reflectance of 0.0860) at which the reflectance is 0.1 or less, and a maximum wavelength of 766 nm (reflectance of 0.1 or less). Since the reflectance is 0.1055), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 358 nm.
That is, the antireflection film 200 of Reference Embodiment 1 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 5, simulation conditions and results regarding an antireflection film 230 according to another embodiment of the present invention will be described with reference to FIGS. 1, 10, and 11. FIG.
As shown in FIGS. 1 and 10, the antireflection film 230 has 14 layers laminated on the optical substrate L formed of S-LAL7 (manufactured by Ohara Co., Ltd.), and each layer is a first type intermediate layer. The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-LAL7 is for a light source with a wavelength of 546 nm.

FIG. 11 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 230 of Embodiment 5 configured as described above is irradiated with incident light.
As shown in FIG. 11, the antireflection film 230 of Embodiment 5 has a minimum wavelength of 409 nm (reflectance of 0.0989) at which the reflectance is 0.1 or less, and a maximum wavelength of 772 nm (reflectance of 0.1 or less). Since the reflectance is 0.1052), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 363 nm.
That is, the antireflection film 230 of Embodiment 5 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 6, simulation conditions and results regarding an antireflection film 260 according to another embodiment of the present invention will be described with reference to FIGS. 1, 12, and 13. FIG.
As shown in FIGS. 1 and 12, the antireflection film 260 has 14 layers laminated on the optical substrate L formed of S-LAL10 (manufactured by Ohara Co., Ltd.). The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-LAL10 is for a light source with a wavelength of 546 nm.

FIG. 13 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 260 of Embodiment 6 configured as described above is irradiated with incident light.
As shown in FIG. 13, the antireflection film 260 of Embodiment 6 has a minimum wavelength of 409 nm (reflectance of 0.1000) at which the reflectance is 0.1 or less, and a maximum wavelength of 771 nm (reflectance of 0.1 or less). Since the reflectance is 0.1044), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 362 nm.
That is, the antireflection film 260 of Embodiment 6 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as reference form 2 , simulation conditions and results regarding the antireflection film 300 of the reference example of the present invention will be described with reference to FIGS. 1, 14, and 15. FIG.
As shown in FIGS. 1 and 14, the antireflection film 300 has 14 layers laminated on the optical substrate L formed of K-GIR140 (manufactured by Sumita Optical Glass Co., Ltd.), each layer being a first-class intermediate layer. A second layer 102, a fourth layer 104, a sixth layer 106, an eighth layer 108, and a tenth layer 110 are made of _SiO2 , a twelfth layer 112 that is a specific intermediate layer, and a fifth layer 105 that is a type 2 intermediate layer. is Ta ₂ O ₅ , and the first layer 101, the third layer 103, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113, which are the second type intermediate layers other than the fifth layer 105, are TiO _2. The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of K-GIR140 is for a light source with a wavelength of 546 nm.

FIG. 15 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 300 of Reference Form 2 configured as described above is irradiated with incident light.
As shown in FIG. 15, the antireflection film 300 of Reference Form 2 has a minimum wavelength of 407 nm (reflectance of 0.0897) at which the reflectance is 0.1 or less, and a maximum wavelength of 771 nm (reflectance of 0.1 or less). Since the reflectance is 0.1054), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 364 nm.
That is, the antireflection film 300 of Embodiment 7 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as an eighth embodiment, simulation conditions and results regarding an antireflection film 330 according to another embodiment of the present invention will be described with reference to FIGS. 1, 16, and 17. FIG.
As shown in FIGS. 1 and 16, the antireflection film 300 has 14 layers laminated on the optical substrate L formed of S-LAH66 (manufactured by Ohara Co., Ltd.), each layer being a first type intermediate layer. The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-LAH66 is for a light source with a wavelength of 546 nm.

FIG. 17 shows the results obtained by simulating the reflectance at each wavelength when the surface of the antireflection film 330 of the eighth embodiment configured as described above is irradiated with incident light.
As shown in FIG. 17, the antireflection film 330 of Embodiment 8 has a minimum wavelength of 409 nm (reflectance of 0.0967) at which the reflectance is 0.1 or less, and a maximum wavelength of 771 nm (reflectance of 0.1 or less). Since the reflectance is 0.1081), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 362 nm.
That is, the antireflection film 330 of Embodiment 8 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 9, simulation conditions and results regarding an antireflection film 360 according to another embodiment of the present invention will be described with reference to FIGS. 1, 18, and 19. FIG.
As shown in FIGS. 1 and 18, the antireflection film 360 has 14 layers laminated on the optical substrate L made of synthetic quartz. 104, the sixth layer 106, the eighth layer 108 and the tenth layer 110 are _SiO2 , the twelfth layer 112 which is the specific intermediate layer and the first layer 101 which is the second type intermediate layer _{are Ta2O5} , the first layer The third layer 103, the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113, which are the second type intermediate layers other than 101, are TiO ₂ , and the outermost layer is the fourteenth layer. 114 is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of synthetic quartz is for a light source with a wavelength of 540 nm.

FIG. 19 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 360 of Embodiment 9 configured as described above is irradiated with incident light.
As shown in FIG. 19, the antireflection film 360 of the ninth embodiment has a minimum wavelength of 408 nm (reflectance of 0.0966) at which the reflectance is 0.1 or less, and a maximum wavelength of 771 nm (reflectance of 0.1 or less). Since the reflectance is 0.1046), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 363 nm.
That is, the antireflection film 360 of Embodiment 9 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 10, simulation conditions and results regarding an antireflection film 400 according to another embodiment of the present invention will be described with reference to FIGS. 1, 20, and 21. FIG.
As shown in FIGS. 1 and 20, the antireflection film 400 is formed by stacking 14 layers on the optical substrate L made of BK7, each layer consisting of a second layer 102 and a fourth layer 104, which are first-class intermediate layers. , the sixth layer 106, the eighth layer 108, and the tenth layer 110 are made of _SiO2 , the twelfth layer 112, which is a specific intermediate layer, and the first layer 101, which is a second type intermediate layer, and the third layer 103 _{are Ta2O5} . , the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113, which are the second type intermediate layers other than the first layer 101 and the third layer 103, are TiO ₂ , and the outermost layer is One fourteenth layer 114 is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of BK7 is for a light source with a wavelength of 540 nm.

FIG. 21 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 400 of Embodiment 10 configured as described above is irradiated with incident light.
As shown in FIG. 21, the antireflection film 400 of Embodiment 10 has a minimum wavelength of 405 nm (reflectance of 0.1043) at which the reflectance is 0.1 or less, and a maximum wavelength of 772 nm (reflectance of 0.1 or less). Since the reflectance is 0.1071), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 367 nm.
That is, the antireflection film 400 of the tenth embodiment can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 11, simulation conditions and results regarding an antireflection film 430 according to another embodiment of the present invention will be described with reference to FIGS. 1, 22, and 23. FIG.
As shown in FIGS. 1 and 22, the antireflection film 430 has 14 layers laminated on the optical substrate L formed of S-BAL42 (manufactured by Ohara Co., Ltd.). The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108, and the 10th layer 110 are _SiO2 , the 12th layer 112 which is a specific intermediate layer, and the 1st layer 101 which is a type 2 intermediate layer. The three layers 103 are Ta ₂ O ₅ , the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer, which are second type intermediate layers other than the first layer 101 and the third layer 103. 113 is made of TiO ₂ , and the fourteenth layer 114, which is the outermost layer, is made of MgF ₂ .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-BAL 42 is for a light source with a wavelength of 546 nm.

FIG. 23 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 430 of the eleventh embodiment configured as described above is irradiated with incident light.
As shown in FIG. 23, the antireflection film 430 of Embodiment 11 has a minimum wavelength of 407 nm (reflectance of 0.0897) at which the reflectance is 0.1 or less, and a maximum wavelength of 771 nm (reflectance of 0.1 or less). Since the reflectance is 0.1054), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 364 nm.
That is, the antireflection film 430 of Embodiment 11 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as a twelfth embodiment, simulation conditions and results regarding an antireflection film 460 according to another embodiment of the present invention will be described with reference to FIGS. 1, 24, and 25. FIG.
As shown in FIGS. 1 and 24, the antireflection film 460 has 14 layers laminated on the optical substrate L formed of S-BSM16 (manufactured by Ohara Co., Ltd.). The 2nd layer 102, the 4th layer 104, the 6th layer 106, the 8th layer 108 and the 10th layer 110 are made of _SiO2 , and the 12th layer 112 which is a specific intermediate layer and the 1st layer 101 which is a type 2 intermediate layer are made of Ta. _{2O 5} , the third layer 103 , the fifth layer 105 , the seventh layer 107 , the ninth layer 109 , the eleventh layer 111 and the thirteenth layer 113 which are second-type intermediate layers other than the first layer 101 are TiO ₂ , The fourteenth layer 114, which is the outermost layer, is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.
The refractive index of S-BSM 16 is for a light source with a wavelength of 546 nm.

FIG. 25 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 460 of the twelfth embodiment configured as described above is irradiated with incident light.
As shown in FIG. 25, the antireflection film 460 of Embodiment 12 has a minimum wavelength of 409 nm (reflectance of 0.0961) at which the reflectance is 0.1 or less, and a maximum wavelength of 773 nm (reflectance of 0.1 or less). Since the reflectance is 0.1094), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 364 nm.
That is, the antireflection film 460 of Embodiment 12 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as a thirteenth embodiment, simulation conditions and results regarding an antireflection film 500 according to another embodiment of the present invention will be described with reference to FIGS. 1, 26, and 27. FIG.
As shown in FIGS. 1 and 26, the antireflection film 500 is laminated in 14 layers on the optical substrate L made of BK7, and each layer is a second layer 102 which is a first type intermediate layer including a specific intermediate layer. , the fourth layer 104, the sixth layer 106, the eighth layer 108, the tenth layer 110, and the twelfth layer 112 are _SiO2 , and the first layer 101 and the third layer 103, which are intermediate layers of the second kind, _{are Ta2O5} . , the fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113, which are second-type intermediate layers other than the first layer 101 and the third layer 103, are TiO ₂ , and the outermost layer is One fourteenth layer 114 is made of _MgF2 .
The refractive index and physical film thickness of each layer are as shown in FIG.

FIG. 27 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 500 of Embodiment 13 configured as described above is irradiated with incident light.
As shown in FIG. 27, the antireflection film 500 of the thirteenth embodiment has a minimum wavelength of 407 nm (reflectance of 0.0884) at which the reflectance is 0.1 or less, and a maximum wavelength of 767 nm (reflectance of 0.1 or less). Since the reflectance is 0.1042), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 364 nm.
That is, the antireflection film 500 of Embodiment 13 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

Next, as Embodiment 14, simulation conditions and results regarding an antireflection film 530 according to another embodiment of the present invention will be described with reference to FIGS. 1, 28, and 29. FIG.
As shown in FIGS. 1 and 28, the antireflection film 530 has 14 layers laminated on the optical substrate L made of BK7, and each layer consists of the second layer 102 and the fourth layer 104, which are first-class intermediate layers. , the sixth layer 106, the eighth layer 108, and the tenth layer 110 are made of _SiO2 , the twelfth layer 112, which is a specific intermediate layer, is Al2O3, and the first layer 101, which is a type 2 intermediate layer, and the third layer 103 are _Ta2. The _fifth layer 105, the seventh layer 107, the ninth layer 109, the eleventh layer 111, and the thirteenth layer 113, which are second-type intermediate layers other than O5, the first layer 101, and the third layer 103, are _TiO2 , and the maximum The fourteenth layer 114, which is the outer layer, is made of _MgF2 .
The refractive index and physical thickness of each layer are as shown in FIG.
Note that the refractive index of AL ₂ O ₃ is for a wavelength of 540 nm.

FIG. 29 shows the results obtained by simulation of the reflectance at each wavelength when the surface of the antireflection film 530 of Embodiment 14 configured as described above is irradiated with incident light.
As shown in FIG. 29, the antireflection film 530 of Embodiment 14 has a minimum wavelength of 407 nm (reflectance of 0.0916) at which the reflectance is 0.1 or less, and a maximum wavelength of 767 nm (reflectance of 0.1 or less). Since the reflectance is 0.1048), the range in which the reflectance is 0.1 or less in the visible light wavelength region becomes a wide range of 360 nm.
That is, the antireflection film 530 of Embodiment 14 can sufficiently transmit incident light over a wide range in the visible light wavelength region.

From the above simulation results, the antireflection film of the present invention achieved a reflectance of 0.1% or less in a continuous wavelength range wider than 330 nm in the visible light wavelength region.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention described in the claims. It is possible.

In the above-described embodiments, the optical substrates are S-LAH55, S-TIH53, S-NPH2, S-LAH79, S-LAL7, S-LAL10, K-GIR140, S-LAH66, synthetic quartz, BK7, S- BAL42, S-BSM16, the first type intermediate layer is _SiO2 , the specific intermediate _{layer is SiO2, Al2O3, Ta2O5, the second type intermediate layer is TiO2, Ta2O5 , and the outermost layer is} MgF2 _. Although the explanation has been given assuming that the refractive index material is formed, the refractive index material forming each layer of the optical substrate and the antireflection film is not limited to this. It may be a layer formed by or a layer formed of a plurality of refractive index materials.
Further, in the above-described embodiment, the antireflection film is described as being composed of 14 layers, but the layer structure of the antireflection film is not limited to this, and may be composed of, for example, 13 layers or less. , 15 or more layers.

DESCRIPTION OF SYMBOLS 100... Anti-reflection film 101... 1st layer 102... 2nd layer 103... 3rd layer 104... 4th layer 105... 5th layer 106... 6th layer 107 ... 7th layer 108 ... 8th layer 109 ... 9th layer 110 ... 10th layer 111 ... 11th layer 112 ... 12th layer 113 ... 13th layer 114・・・ 14th layer (outermost layer)
L: optical substrate

Claims (6)

An antireflection film formed by laminating a plurality of layers having different refractive indices on an optical substrate,
The antireflection film comprises an outermost layer which is the layer farthest from the optical substrate, and a plurality of first-type intermediate layers and a plurality of second-type intermediate layers formed between the outermost layer and the optical substrate. including at least
each of the first-type intermediate layers and each of the second-type intermediate layers is formed of at least one or more refractive index materials,
The layer adjacent to the outermost layer is the second type intermediate layer,
The antireflection film is formed by alternately stacking the first type intermediate layers and the second type intermediate layers, and each of the first type intermediate layers is the second type intermediate layer adjacent to the first type intermediate layer. formed with a lower refractive index than the intermediate layer,
At least one of the first-type intermediate layers sandwiched between the second-type intermediate layers is a specific intermediate layer formed to have a refractive index of 1.75 or more and less than 2.7 in the wavelength range used. the law of nature,
The type 1 intermediate layer excluding the specific intermediate layer has a refractive index of 1.4 or more and less than 1.75 in the wavelength range used,
The antireflection film , wherein the layer adjacent to the optical substrate _is made of Ta2O5 _. 2. The antireflection film according to claim 1, wherein the specific intermediate layer is formed at least in a layer adjacent to the second type intermediate layer adjacent to the outermost layer. 3. The antireflection film according to claim 1, wherein the outermost layer has a refractive index of 1.3 or more and 1.41 or less in the wavelength range used. 4. The antireflection film according to claim 1 , wherein the refractive index of the second type intermediate layer in the wavelength range used is 2.7 or less. 5. The antireflection film according to claim 1, wherein the optical substrate has a refractive index of 1.4 or more and 2.3 or less. The antireflection film is composed of 14 layers, and when the optical substrate side when laminated on the optical substrate is the first layer,
The physical film thickness of the first layer is 2 nm or more and 30 nm or less,
The physical film thickness of the second layer is 20 nm or more and 70 nm or less,
The physical film thickness of the third layer is 20 nm or more and 60 nm or less,
The physical film thickness of the fourth layer is 2 nm or more and 20 nm or less,
The physical film thickness of the fifth layer is 60 nm or more and 130 nm or less,
The physical film thickness of the sixth layer is 10 nm or more and 45 nm or less,
The physical film thickness of the seventh layer is 5 nm or more and 40 nm or less,
The physical film thickness of the eighth layer is 70 nm or more and 150 nm or less,
The physical film thickness of the ninth layer is 3 nm or more and 60 nm or less,
The physical film thickness of the tenth layer is 10 nm or more and 50 nm or less,
The physical film thickness of the eleventh layer is 20 nm or more and 90 nm or less,
The physical film thickness of the 12th layer is 10 nm or more and 60 nm or less,
The physical film thickness of the thirteenth layer is 2 nm or more and 30 nm or less,
6. The antireflection film according to claim 1, wherein the physical film thickness of the fourteenth layer is 40 nm or more and 200 nm or less.

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