JP2010156765A - Nd filter, method of manufacturing the same and method of controlling transmittance of light using them - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ND filter which has a uniform transmittance characteristic over the whole range of wavelengths of visible region, provides a low haze value, is reduced in thickness and weight, is easily molded, is excellent in shock resistance, has satisfactory adhesion between a transparent resin substrate and an optical attenuation layer, and also has an optical density variable conveniently partially, stepwise or continuously, and also to provide the method of manufacturing the ND filter. <P>SOLUTION: The ND filter has the optical attenuation layer 2 formed of a curable resin composition which contains a pigment and/or dye, on the transparent resin substrate 1, wherein the optical attenuation layer 2 has at least two kinds of thicknesses. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ND filter. Specifically, an ND filter having a light attenuating layer formed from a curable resin composition containing a pigment and / or a dye, wherein the light attenuating layer has at least two kinds of thicknesses, and its production The present invention relates to a method and a method of adjusting light transmittance using the method.

  An ND filter (Neutral Density Filter) is a filter that reduces the amount of light that passes through the filter, and is used in solid-state imaging devices such as digital still cameras and digital video cameras. There is a demand for prevention of haze values, shading phenomenon and resolution reduction.

  As such an ND filter, conventionally, a glass filter in which a light absorbing material is added to glass has been used. However, this glass filter has problems that the spectral characteristics are not uniform in the visible light region, and that the weight is reduced, the molding is easy, and the impact resistance is inferior.

In order to solve the above problems, recently, a filter using a resin as a substrate has been developed instead of a glass filter.
A general resin ND filter uses a substrate made of PET (polyethylene terephthalate), vinyl chloride or the like, and a metal film having a light absorbing ability on the substrate and a metal oxide for controlling transmission / reflection ability. It is roughly classified into a reflection absorption type ND filter obtained by vapor-depositing a dielectric film made of, etc. in vacuum, and a light absorption type ND filter produced by uniformly dispersing a dye and a pigment in a transparent material.

  However, the former requires multi-layer coating by vacuum deposition, so in order to ensure the reproducibility of ND filter manufacturing and the uniformity of optical characteristics within the filter surface, the substrate size should be kept constant from the deposition source. It was necessary to reduce the size, and there were many inferior adhesion between the substrate and the dielectric film. On the other hand, in the latter light absorption type ND filter, a uniform transmittance characteristic is often not obtained over the entire visible wavelength range depending on the properties of the dye or pigment used.

  In recent years, as digital cameras and video cameras have become more sophisticated and smaller in size, there is a strong demand for ND filters that change the optical density by changing the light transmission position in a single ND filter. It came to be able to.

  In contrast, in Patent Document 1, an ND filter in which a plurality of masks are formed by a vapor deposition method and regions having different optical densities are formed on the substrate surface is orthogonal to the evaporation flying direction of the evaporation source in Patent Document 2. A method of manufacturing an ND filter in which an optical density continuously changes by inclining a substrate at a predetermined angle with respect to a plane and further depositing a mask with a predetermined angle between the substrate and a vapor deposition source. Proposed.

However, in the conventional method, a plurality of masks having different opening sizes are overlapped to control the deposition thickness. Therefore, if the respective masks are not sufficiently cleaned, the previous deposition is performed when the masks are overlapped. Vapor deposition material is peeled off, and as a result, it adheres to the substrate as a foreign substance, and the image quality deteriorates or the substrate and the mask are inclined so that it can easily cope with the design change of the ND filter. In addition, there are problems such as poor reproducibility between batches in which the product characteristics vary due to slight changes in the tilt angle.
JP 2004-37548 A JP-A-11-38206

  The present invention relates to an ND filter having a uniform transmittance characteristic over the entire wavelength in the visible region, good adhesion between the substrate and the light attenuating layer, and partially, stepwise, or continuously different optical densities, and its manufacture. The challenge is to provide a method. ND filter with low haze value, anti-shading phenomenon, anti-reflection properties to prevent resolution degradation, image ghosting and flare, and excellent thickness reduction, weight reduction, ease of molding, and impact resistance It is an object to provide a manufacturing method thereof.

  In addition, the present invention eliminates the poor reproducibility of multilayer film formation in vacuum deposition, the complexity of the process and the accompanying yield reduction, and the inconvenience to the design change of the shape and optical density, and with good reproducibility. It is another object of the present invention to provide an ND filter that easily changes optical density partially, stepwise, or continuously and a method for manufacturing the ND filter.

  The ND filter of the present invention has a light attenuating layer formed from a curable resin composition containing a pigment and / or a dye on a transparent resin substrate, and the light attenuating layer has at least two thicknesses. It is characterized by that.

In the ND filter of the present invention, it is preferable that the thickness of the light attenuation layer is changed partially, stepwise, or continuously.
In the ND filter of the present invention, it is preferable that the transparent resin substrate has a substantially constant thickness.

In the ND filter of the present invention, the transparent resin substrate preferably has at least two types of thickness.
In the ND filter of the present invention, it is preferable that the thickness of the transparent resin substrate is changed partially, stepwise or continuously.

In the ND filter of the present invention, it is preferable that at least one surface of the transparent resin substrate is further subjected to antireflection treatment.
In the ND filter of the present invention, the transparent resin substrate is preferably composed of a cyclic olefin polymer having a structural unit derived from a monomer containing at least one compound represented by the following formula (1).

[In the formula (1), x represents 0 or an integer of 1 to 3, and y represents 0 or 1.
R ^{1 to} R ⁴ each independently represents one selected from the following (i) to (v), or (vi) or (vii).

(I) a hydrogen atom,
(Ii) a halogen atom,
(Iii) polar group,
(Iv) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms having a linking group containing an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom;
(V) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms,
(Vi) R ¹ and R ² , or R ³ and R ⁴ represent an alkylidene group formed by bonding to each other, and R ^{1 to} R ⁴ not participating in the bonding are independently of each other, Represents one selected from (i) to (v),
(Vii) an aromatic ring or a non-aromatic monocyclic or polycyclic carbocyclic ring formed by bonding R ¹ and R ² , R ³ and R ⁴ , or R ² and R ³ to each other; R ^{1 to} R ⁴ which represent a heterocyclic ring and are not involved in the bond are independently selected from the above (i) to (v). ]
In the ND filter of the present invention, at an arbitrary point, the average value of the light transmittance at a wavelength of 450 to 650 nm is T _ave (%), the minimum value of the light transmittance is T _min (%), and the maximum value of the light transmittance is When T _max (%), it is preferable that these satisfy the following formulas (2), (3) and (4).

T _ave ≦ 70 (2)
0.85 × T _ave ≦ T _min (3)
1.15 × T _ave ≧ T _max (4)
In the ND filter of the present invention, it is preferable that the pigment contains at least one inorganic particle selected from carbon black, metal oxide, metal nitride, and metal nitride oxide.

In the ND filter of the present invention, the pigment is preferably a metal complex oxide composed of copper, iron and manganese oxides.
In the ND filter of the present invention, the pigment is preferably a metal composite oxide composed of copper, iron, and manganese.

The ND filter of the present invention is preferably a composition in which the curable resin composition is cured by active energy rays.
In the ND filter of the present invention, the curable resin composition preferably contains (meth) acrylate having an alicyclic structure.

  The method for producing an ND filter of the present invention includes a step (1) of forming a curable layer comprising a curable resin composition containing a pigment and / or a dye on a transparent resin substrate, and curing the curable layer. And (2) forming an optical attenuation layer having at least two kinds of thicknesses.

  In the manufacturing method of the ND filter of the present invention, after the step (2) forms a curable layer, the surface shape of the roll is transferred to the curable layer using a roll having a non-smooth surface. It is preferable to cure the curable layer.

  In the manufacturing method of the ND filter of the present invention, after the step (2) forms the curable layer, the thickness of the second transparent resin layer that has been changed in thickness in advance is changed on the curable layer. It is preferable to superimpose a certain side toward the curable layer and cure the curable layer in the superimposed state.

The ND filter of the present invention is preferably manufactured by the above manufacturing method.
Furthermore, the present invention relates to a method for adjusting light transmittance using the ND filter of the present invention.

  According to the present invention, the ND filter has a uniform transmittance characteristic over the entire wavelength in the visible region, and has good adhesion between the substrate and the light attenuation layer, and has different optical densities, partially, stepwise, or continuously. And a manufacturing method thereof. ND filter with low haze value, anti-shading phenomenon, anti-reflection properties to prevent resolution degradation, image ghosting and flare, and excellent thickness reduction, weight reduction, ease of molding, and impact resistance And a manufacturing method thereof.

  In addition, the present invention eliminates the poor reproducibility of multilayer film formation in vacuum deposition, the complexity of the process and the accompanying yield reduction, and the inconvenience to the design change of the shape and optical density, and with good reproducibility. In addition, it is possible to provide an ND filter that easily changes the optical density partially, stepwise, or continuously, and a method for manufacturing the ND filter.

  Furthermore, since the thickness of the light attenuation layer of the ND filter of the present invention changes partially, stepwise, or continuously, it provides in-plane variability of dimming performance within a single ND filter. It is possible to adjust the light transmittance. Therefore, it is possible to drastically improve the performance of imaging devices such as digital cameras and digital still cameras at low cost.

Hereinafter, the present invention will be specifically described.
[ND filter]
The ND filter of the present invention has a light attenuating layer formed from a curable resin composition containing a pigment and / or a dye on a transparent resin substrate, and the light attenuating layer has at least two thicknesses. .

The thickness of the light attenuation layer may be changed partially, stepwise, or continuously.
Furthermore, the transparent resin substrate may have a substantially constant thickness, or may have at least two types of thickness.

The thickness of the transparent resin substrate may be changed partially, stepwise or continuously.
The thickness of the transparent resin substrate and the light attenuation layer or the degree of change thereof can be changed depending on the required shape and function of the ND filter.

In the ND filter of the present invention, at an arbitrary point, the average value of the light transmittance at a wavelength of 450 to 650 nm when the thickness of the ND filter is 0.1 mm is T _ave (%), and the minimum value of the light transmittance is T _min (% ), Where the maximum value of the light transmittance is T _max (%), these satisfy the following formulas (2), (3) and (4): T _ave ≦ 70 (2)
0.85 × T _ave ≦ T _min (3)
1.15 × T _ave ≧ T _max (4)
The above formula (2) indicates that the ND filter of the present invention needs to cut light at least 30% at a wavelength of 450 to 650 nm, and the above formulas (3) and (4) represent the light beam of the ND filter. It indicates that the transmittance is almost uniform at a wavelength of 450 to 650 nm, that is, the spectral transmittance curve has flatness and small variation.

It is preferable that the spectral transmittance curve has flatness because the balance of the color of transmitted light is maintained and shading can be prevented.
It is desirable that the average value T _ave (%) of light transmittance at a wavelength of 450 to 650 nm is 70% or less, preferably 50% or less, more preferably 40% or less.

It is desirable that the minimum value T _min (%) of the light transmittance at a wavelength of 450 to 650 nm is 0.85 times or more, preferably 0.90 times or more, more preferably 0.92 times or more of T _ave . Further, the minimum value T _min (%) of the light transmittance is not more than 1 times T _ave .

It is desirable that the maximum value T _max (%) of the light transmittance at a wavelength of 450 to 650 nm is 1.15 times or less, preferably 1.10 times or less, more preferably 1.08 times or less of T _ave . Further, the maximum value T _max (%) of the light transmittance is at least one time _Tave .

  When the minimum value and the maximum value of the light transmittance at a wavelength of 450 to 650 nm of the ND filter are in the above range, an ND filter having uniform transmittance characteristics at a wavelength of 450 to 650 nm can be obtained.

  Such flatness of the spectral transmittance curve can be achieved by forming a light attenuation layer made of a curable resin composition containing a specific pigment and / or dye on a transparent resin substrate.

Specifically, it can be achieved by using a pigment or dye having a substantially uniform spectral transmittance curve at a wavelength of 450 to 650 nm.
If the spectral transmittance curve of the ND filter does not become flat just by containing a specific pigment in the light attenuation layer formed on the transparent resin substrate, the light transmittance layer near the maximum value (T _max ) in the visible light region. The spectral transmittance curve of the ND filter can be flattened by using a specific dye having absorption in the wavelength region (the wavelength region of the A portion in FIG. 7) together with the pigment.

In addition, if the spectral transmittance curve of the ND filter does not become flat just by containing a specific pigment and / or dye in the light attenuation layer formed on the transparent resin substrate, the minimum value of the light transmittance in the visible light region The spectral transmittance curve of the ND filter is obtained by performing antireflection treatment on at least one surface of the ND filter so that the reflectance in the wavelength region in the vicinity of (T _min ) (the wavelength region of the B portion in FIG. 7) is low. It can also be made flat.
≪Transparent resin substrate≫
The transparent resin substrate in the present invention may be a transparent resin film or a transparent resin sheet. Here, the difference between a film and a sheet is not strictly defined, but generally, a film having a thickness of 200 μm or less is called a film, and a film having a thickness larger than that is called a sheet, and there is no distinction depending on the material.

  Since such a transparent resin substrate is formed from a transparent resin, the spectral characteristics are uniform in the visible light region, and because it is thin, lightweight, easy to mold, and excellent in impact resistance, preferable.

The transparent resin substrate in the present invention may have a substantially constant thickness, or may have at least two types of thickness.
Further, the thickness of the transparent resin substrate may be changed partially, stepwise or continuously.

The thickness of the transparent resin substrate or the degree of change thereof can be changed according to the required shape and function of the ND filter.
In the present invention, the thickness of the transparent resin substrate is not particularly limited, but the thinnest part and the thickest part are preferably in the range of 1 to 2000 μm, and preferably in the range of 10 to 500 μm.

When the thickness of the transparent resin substrate is in the above range, it is preferable in that the transparency in the visible light region is good and the substrate strength can be maintained.
<Transparent resin>
The transparent resin used in the present invention is not particularly limited as long as it does not impair the effects of the present invention. For example, the glass transition temperature (Tg) is 100 to 500 ° C. and the total light transmission is 100 μm in thickness. A resin having a rate of 75% or more can be used.

  As a transparent resin used in the present invention, the glass transition temperature (Tg) is usually 100 to 380 ° C., preferably 100 to 370 ° C., more preferably 120 to 120 ° C. in order to ensure thermal stability and moldability to a substrate. 360 ° C. Moreover, if the glass transition temperature of transparent resin is 120 degreeC or more, Preferably it is 130 degreeC or more, More preferably, since the board | substrate which is excellent in thermal stability is obtained, it is desirable.

  As a transparent resin used in the present invention, the total light transmittance at a thickness of 0.1 mm is usually 75 to 94%, preferably 78 to 93%, and more preferably 80 to 92%. If the total light transmittance is in such a range, the transparent resin substrate exhibits good transparency, and a transparent resin substrate having a small haze value is obtained, which is preferable.

  Examples of such transparent resins include cyclic olefin resins such as norbornene resins, polyarylate resins (PAR), polysulfone resins (PSF), polyethersulfone resins (PES), polyparaphenylene resins (PPP), poly Arylene ether phosphine oxide resin (PEPO), polyimide resin (PPI), polyetherimide resin (PEI), polyamideimide resin (PAI), (modified) acrylic resin, polycarbonate (PC), polyethylene naphthalate (PEN), organic -Inorganic nanohybrid materials can be mentioned.

The use of the transparent resin is preferable because a substrate showing good transparency can be obtained and the adhesiveness with the curable resin composition is excellent.
In the present invention, among these, it is particularly preferable to use a cyclic olefin resin.

<Cyclic olefin resin>
As the cyclic olefin-based resin used in the present invention, a resin obtained by polymerizing a monomer composition containing at least one cyclic olefin-based compound and further hydrogenating as necessary is preferable.

  The cyclic olefin resin is excellent in transparency in the visible light region, high heat resistance, low water absorption, low specific gravity, moldability, adhesion to metal film, chemical resistance, etc. Preferred as a substrate.

<Monomer composition>
Examples of the cyclic olefin compound used in the monomer composition include a cyclic olefin compound represented by the following general formula (1).

[In the formula (1), x represents 0 or an integer of 1 to 3, and y represents 0 or 1.
R ^{1 to} R ⁴ each independently represents one selected from the following (i) to (v), or (vi) or (vii).

(I) a hydrogen atom,
(Ii) a halogen atom,
(Iii) polar group,
(Iv) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms having a linking group containing an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom;
(V) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms,
(Vi) R ¹ and R ² , or R ³ and R ⁴ represent an alkylidene group formed by bonding to each other, and R ^{1 to} R ⁴ not participating in the bonding are independently of each other, Represents one selected from (i) to (v),
(Vii) an aromatic ring or a non-aromatic monocyclic or polycyclic carbocyclic ring formed by bonding R ¹ and R ² , R ³ and R ⁴ , or R ² and R ³ to each other; R ^{1 to} R ⁴ which represent a heterocyclic ring and are not involved in the bond are independently selected from the above (i) to (v). ]
Specific examples of the cyclic olefin-based compound represented by the general formula (1) include, for example, the compounds shown below, but are not limited to these examples.
Bicyclo [2.2.1] hept-2-ene (norbornene)
5-methyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2.1] hept-2-ene, 5-propylbicyclo [2.2.1] hepta 2-ene, 5-butylbicyclo [2.2.1] hept-2-ene, 5-t-butylbicyclo [2.2.1] hept-2-ene, 5-isobutylbicyclo [2.2.1] ] Hept-2-ene, 5-pentylbicyclo [2.2.1] hept-2-ene, 5-hexylbicyclo [2.2.1] hept-2-ene, 5-heptylbicyclo [2.2. 1] Hept-2-ene, 5-octylbicyclo [2.2.1] hept-2-ene, 5-decylbicyclo [2.2.1] hept-2-ene, 5-dodecylbicyclo [2.2 .1] hept-2-ene-5-cyclohexyl-bicyclo [2.2.1 Hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene, 5- (4-biphenyl) -bicyclo [2.2.1] hept-2-ene, 5-methoxycarbonyl -Bicyclo [2.2.1] hept-2-ene-5-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene / 5-phenoxyethylcarbonyl-bicyclo [2.2.1] hept- 2-ene-5-phenylcarbonyloxy-bicyclo [2.2.1] hept-2-ene-5-methyl-5-methoxycarbonyl-bicyclo [2.2.1] hept-2-ene-5-methyl -5-phenoxycarbonyl-bicyclo [2.2.1] hept-2-ene-5-methyl-5-phenoxyethylcarbonyl-bicyclo [2.2.1] hept-2-ene-5-vinyl-bicycl [2.2.1] Hept-2-ene / 5-ethylidene-bicyclo [2.2.1] hept-2-ene / 5-trimethoxysilyl-bicyclo [2.2.1] hept-2-ene 5-triethoxysilyl-bicyclo [2.2.1] hept-2-ene5,5-dimethyl-bicyclo [2.2.1] hept-2-ene5,6-dimethyl-bicyclo [2 2.1] hept-2-ene, 5-fluoro-bicyclo [2.2.1] hept-2-ene, 5-chloro-bicyclo [2.2.1] hept-2-ene, 5-bromo -Bicyclo [2.2.1] hept-2-ene, 5,6-difluoro-bicyclo [2.2.1] hept-2-ene, 5,6-dichloro-bicyclo [2.2.1] hept 2-ene-5,6-dibromo-bicyclo [2.2.1] hept-2-ene 5-hydroxy-bicyclo [2.2.1] hept-2-ene, 5-hydroxyethyl-bicyclo [2.2.1] hept-2-ene, 5-cyano-bicyclo [2.2.1] hept 2-ene-5-amino-bicyclo [2.2.1] hept-2-ene tricyclo [4.3.0.1 ^2,5 ] dec-3-ene tricyclo [4.4.0. 1 ^2,5 ] undec-3-ene · 7-methyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene · 7-ethyl-tricyclo [4.3.0.1 ^2,5 Deca-3-ene · 7-cyclohexyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene · 7-phenyl-tricyclo [4.3.0.1 ^2,5 ] deca-3 - en 7- (4-biphenyl) - tricyclo [4.3.0.1 ^{2, 5]} dec-3-ene-7,8-dimethyl - Torishiku [4.3.0.1 ^{2, 5]} dec-3-ene-7,8,9- trimethyl - tricyclo [4.3.0.1 ^{2, 5]} dec-3-ene-8-methyl - tricyclo [4.4.0.1 ^2,5 ] Undec-3-ene · 8-phenyl-tricyclo [4.4.0.1 ^2,5 ] Undec-3-ene · 7-fluoro-tricyclo [4.3 .0.1 ^2,5] dec-3-ene-7-chloro - tricyclo [4.3.0.1 ^2,5] dec-3-ene-7-bromo - tricyclo [4.3.0.1 ^2,5 ] dec-3-ene.7,8-dichloro-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene.7,8,9-trichloro-tricyclo [4.3.0 .1 ^2,5] dec-3-ene-7-chloromethyl - tricyclo [4.3.0.1 ^2,5] dec-3-ene-7-dichloromethyl - tricyclo [4.3.0.1 ^2,5 ] dec-3-ene.7-trichloromethyl-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene.7-hydroxy-tricyclo [4.3.0.1 ^2,5 Deca-3-ene · 7-cyano-tricyclo [4.3.0.1 ^2,5 ] dec-3-ene · 7-amino-tricyclo [4.3.0.1 ^2,5 ] deca-3 -Ene tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene pentacyclo [7.4.0.1 ^2,5 . 1 ^8,11 . 0 ^7,12] pentadeca-3-ene-hexacyclo [8.4.0.1 ^2,5. 1 ^7,14 . 1 ^9,12 . 0 ^8,13] heptadec-3-en-8-methyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodeca-3-ene-8-ethyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodeca-3-ene-8-cyclohexyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene-8-phenyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8- (4-biphenyl) -tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene-8-methoxycarbonyloxy - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene-8-phenoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene-8-phenoxyethyl carbonyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene-8-phenylcarbonyloxy-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-methyl-8-methoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-methyl-8-phenoxycarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-methyl-8-phenoxyethylcarbonyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-vinyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene-8-ethylidene - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodeca-3-ene-8,8-dimethyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10] dodeca-3-ene-8,9-dimethyl - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene-8-fluoro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-chloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene-8-bromo - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene.8,8-dichloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene.8,9-dichloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene. 8,8,9,9-tetrachloro-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-hydroxy-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-hydroxyethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene-8-methyl-8-hydroxyethyl-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10] dodeca-3-ene-8-cyano - tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] dodec-3-ene-8-amino-tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene In addition, these cyclic olefin type compounds may be used individually by 1 type, and may use 2 or more types together.

The kind and amount of the cyclic olefin compound used in the present invention are appropriately selected depending on the properties required for the obtained resin.
Of these, when a compound having a structure containing at least one atom selected from an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom in the molecule (hereinafter referred to as “polar structure”) is used. There are advantages such as excellent dispersibility of the absorbent and excellent adhesion and adhesion to other materials. In particular, in the formula (1), R ¹ and R ³ are a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, preferably a hydrogen atom or a methyl group, and any one of R ^{2 and} R ⁴ is A compound having a polar structure and the other being a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms is preferable because the water absorption (wet) property of the resin is low. Furthermore, a cyclic olefin compound in which the group having a polar structure is a group represented by the following general formula (5) is easy to balance the heat resistance and water absorption (wet) property of the resulting resin, and can be preferably used. .

_{- (CH 2) z COOR ...} (5)
(In formula (5), R represents a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms, and z represents 0 or an integer of 1 to 10).
In the general formula (5), the smaller the value of z, the higher the glass transition temperature of the resulting hydrogenated product and the better the heat resistance. Therefore, z is preferably an integer of 0 or 1 to 3, A monomer in which z is 0 is preferable in that its synthesis is easy. Further, R in the general formula (5) tends to decrease the water absorption (wetness) of the hydrogenated polymer obtained as the carbon number increases, but also tends to decrease the glass transition temperature. From the viewpoint of maintaining heat resistance, a hydrocarbon group having 1 to 10 carbon atoms is preferable, and a hydrocarbon group having 1 to 6 carbon atoms is particularly preferable.

  In the general formula (1), when an alkyl group having 1 to 3 carbon atoms, particularly a methyl group, is bonded to the carbon atom to which the group represented by the general formula (5) is bonded, heat resistance and water absorption It is preferable in terms of (wet) balance. Furthermore, in the general formula (1), a compound in which x is 0 and y is 0 or 1 has high reactivity, a polymer can be obtained in a high yield, and polymer hydrogen having high heat resistance. It is preferably used because an additive is obtained and it is industrially easily available.

  In obtaining the cyclic olefin-based resin used in the present invention, the monomer composition can be polymerized with a monomer copolymerizable with the cyclic olefin-based compound as long as the effects of the present invention are not impaired. .

  Examples of these copolymerizable monomers include cyclic olefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and cyclododecene, and non-conjugated cyclic polyenes such as 1,4-cyclooctadiene, dicyclopentadiene, and cyclododecatriene. be able to.

These copolymerizable monomers may be used alone or in combination of two or more.
<Polymerization method>
The method for polymerizing the monomer composition containing the cyclic olefin compound is not particularly limited as long as the monomer composition can be polymerized. For example, the polymerization is performed by ring-opening polymerization or addition polymerization. can do.

《Hydrogenation reaction》
The polymer obtained by the ring-opening polymerization reaction has an olefinically unsaturated bond in the molecule. Moreover, also in the said addition polymerization reaction, a polymer may have an olefinically unsaturated bond in the molecule | numerator. Thus, if an olefinically unsaturated bond is present in the polymer molecule, the olefinically unsaturated bond may cause deterioration over time such as coloring or gelation. It is preferable to carry out a hydrogenation reaction to convert to.

  In the hydrogenation reaction, a known hydrogenation catalyst is added to an ordinary method, that is, a polymer solution having an olefinically unsaturated bond, and hydrogen gas at normal pressure to 300 atm, preferably 3 to 200 atm, is added to the solution. The reaction can be carried out at -200 ° C, preferably 20-180 ° C.

The hydrogenation rate of the hydrogenated polymer is usually 50% or more, preferably 70% or more, more preferably 90% or more, particularly preferably 98% or more, and most preferably 99%, as measured by 500 MHz and ¹ H-NMR. That's it. The higher the hydrogenation rate, the better the stability to heat and light, and it is preferable because stable characteristics can be obtained over a long period when used as a molded product.

≪Method for manufacturing transparent resin substrate≫
A transparent resin substrate having a uniform thickness can be molded by any method such as a casting method or an extrusion molding method using the transparent resin.

Examples of the method for producing transparent resin substrates having different thicknesses include the following (i) to (iv).
(I) Transparent resin substrate having a laminated portion By laminating one or more transparent resin substrates having a uniform thickness in an arbitrary area at an arbitrary location on the transparent resin substrate having a uniform thickness created by the manufacturing method described above. A transparent resin substrate having parts with different thicknesses of the substrate partially or stepwise is manufactured.

(Ii) Transparent resin substrate formed by injection molding Using a mold having a portion having a different thickness at an arbitrary place and a shape having an arbitrary area, a portion having a different thickness is partially formed by injection molding. A transparent resin substrate having a continuous or continuous structure is produced.

(Iii) Transparent resin substrate formed by hot pressing method The transparent resin substrate having a uniform thickness is controlled to have an arbitrary thickness by a method such as hot pressing, and then a portion having a different thickness by a known punching method. A transparent resin substrate having a part, stepwise or continuous is produced.

(Iv) Transparent resin substrate formed by roll pressing method When the transparent resin substrate is extruded and molded, it is controlled so as to obtain an arbitrary thickness by pressing a roll having a non-smooth surface. A transparent resin substrate having parts with different thicknesses partially, stepwise, or continuously is produced by the above method.

  In particular, when an ND filter is prepared using the above manufacturing method (iii) that prepares a mold and obtains a predetermined shape, it is easy to reduce the thickness of the substrate, thereby adjusting the production amount, changing the design of the transparent resin substrate, and the like. This is particularly preferable because it is highly adaptable and has a small number of steps, so that productivity and yield can be improved.

≪Light attenuation layer≫
The light attenuating layer of the present invention is a layer obtained by curing a curable resin composition containing a pigment and / or dye on a transparent resin substrate, and preferably has excellent adhesion to the transparent resin substrate.

The light attenuating layer may be formed on one side of the transparent resin substrate, or may be formed on both sides, but it is necessary to have light attenuating layers having different thicknesses in a single ND filter.
The thickness of the light attenuation layer may be changed partially, stepwise, or continuously.

The thickness of the transparent resin substrate and the light attenuation layer or the degree of change thereof can be changed depending on the required shape and function of the ND filter.
In the present invention, the thickness of the light attenuation layer is not particularly limited, but the thinnest part and the thickest part are preferably in the range of 0.1 to 1000 μm, and preferably in the range of 1 to 200 μm.

  If the thickness of the light attenuating layer is in the above range, the ND filter absorbs light appropriately in the visible light region, so that an ND filter having a desired optical density can be easily manufactured.

  The light attenuating layer can be formed by applying a curable resin composition in a liquid or suspension form on a transparent resin substrate, drying it if necessary, and irradiating it with heating and / or active energy rays.

The light attenuating layer is not particularly limited as long as it constitutes the ND filter of the present invention having the above characteristics, but at any one point, the average value of light transmittance at a wavelength of 450 to 650 nm with a thickness of 0.1 mm. _Is T _ave (%), the minimum value of light transmittance is T _min (%), and the maximum value of light transmittance is T _max (%), these are the following formulas (2), (3) and (4): ) Is preferably satisfied.

T _ave ≦ 70 (2)
0.85 × T _ave ≦ T _min (3)
1.15 × T _ave ≧ T _max (4)
The above equation (2) indicates that the light attenuation layer needs to cut light at least 30% at a wavelength of 450 to 650 nm, and the above equations (3) and (4) indicate the light transmission of the light attenuation layer. It indicates that the ratio is substantially uniform at a wavelength of 450 to 650 nm, that is, the spectral transmittance curve has flatness and small variation.

It is preferable that the spectral transmittance curve has flatness because it has characteristics such as maintaining the color balance of transmitted light.
It is desirable that the average value T _ave (%) of light transmittance at a wavelength of 450 to 650 nm is 70% or less, preferably 50% or less, more preferably 40% or less.

It is desirable that the minimum value T _min (%) of the light transmittance at a wavelength of 450 to 650 nm is 0.85 times or more, preferably 0.90 times or more, more preferably 0.92 times or more of T _ave . Further, the minimum value T _min (%) of the light transmittance is not more than 1 times T _ave .

It is desirable that the maximum value T _max (%) of the light transmittance at a wavelength of 450 to 650 nm is 1.15 times or less, preferably 1.10 times or less, more preferably 1.08 times or less of T _ave . Further, the maximum value T _max (%) of the light transmittance is at least one time _Tave .

  When the minimum value and the maximum value of the light transmittance at a wavelength of 450 to 650 nm of the light attenuation layer are in the above range, an ND filter having a uniform transmittance characteristic at a wavelength of 450 to 650 nm can be obtained.

<Curable resin composition>
The curable resin composition used in the present invention comprises a pigment and / or dye and a curable resin component.

  In the mixing of the curable resin composition, a pigment and / or a dye are usually mixed in a liquid or suspended curable resin component, and stirred and mixed so that the pigment and / or the dye are uniformly dispersed. Is done by. At this time, by adjusting the stirring method, stirring speed, stirring force, stirring time, and the like, the particle distribution and aggregation state can be controlled.

Any of the methods known in the art can be used for dispersing / stirring the pigment and / or dye.
<< Curable resin component >>
The curable resin component is cured by heating and / or irradiation with active energy rays to form a resin.

The curable resin component is preferably composed of a photocurable resin or a thermosetting resin for reasons such as ease of curing and ease of molding of the light attenuation layer.
The curable resin component used in the present invention is preferably a resin component having a small difference in refractive index from the transparent resin.

Furthermore, it is desirable that the difference in refractive index at 589 nm measured with an Abbe refractometer is within 0.1, preferably within 0.05, more preferably within 0.02.
An ND filter using such a curable resin component is preferable because it can prevent resolution reduction, image ghosting, and flare.

As a material constituting the resin component, for example, an epoxy material, an oxetane material, a silicone material, a melamine material, or a (meth) acrylic material can be suitably used.
As the curable resin component used in the present invention, it is particularly preferable to use an active energy ray curable resin component for reasons such as ease of curing and ease of forming the light attenuation layer.

As a material constituting the active energy ray-curable resin component, a (meth) acrylic material can be preferably used.
The (meth) acrylic material is preferably composed of (A) urethane (meth) acrylate and (B) an ethylenically unsaturated group-containing compound other than the component (A). In this case, the (meth) acrylic material is ethylenic other than (A) urethane (meth) acrylate 5 to 70% by weight and (B) the component (A) with respect to the total amount of (meth) acrylic material. It is preferable to blend 10 to 80% by weight of the unsaturated group-containing compound.

  More preferably, the (meth) acrylic material is a (meth) acrylate having an alicyclic structure as the component (C), particularly as a part of the component (B) in the mixture of the components (A) and (B). Is preferably included.

In this case, the (meth) acrylic material may be formed by blending 80 to 20% by weight of (meth) acrylate having an alicyclic structure as the component (C) with respect to the total amount of the (meth) acrylic material. preferable.
The component (A) is particularly preferably a reaction product of (a) a hydroxyl group-containing (meth) acrylate, (b) an aliphatic polyisocyanate, and (c) a polyol. By making the component (A) this reactant, the refractive index of the active energy ray-curable resin component can be easily controlled, an appropriate hardness can be imparted at the time of curing, and excessive curing shrinkage can be suppressed. It becomes possible to reduce the general distortion. It is also possible to reduce yellowing of the ND filter due to light when the ND filter is used for a long time.

  Examples of the hydroxyl group-containing (meth) acrylate used as the component (a) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 2-hydroxy-3. -Phenyloxypropyl (meth) acrylate, 1,4-butanediol mono (meth) acrylate, 2-hydroxyalkyl (meth) acryloyl phosphate, 4-hydroxycyclohexyl (meth) acrylate, 1,6-hexanediol mono (meth) ) Acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolethane di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentae Sri penta (meth) acrylate.

Among these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and pentaerythritol tri (meth) acrylate are preferable.
These hydroxyl group-containing (meth) acrylates can be used singly or in combination of two or more.

  The aliphatic polyisocyanate used as the component (b) is a compound not containing an aromatic ring structure and containing two or more isocyanate groups. (A) Instead of the polyisocyanate having an aromatic ring structure used as a raw material for urethane (meth) acrylate, (b) an aliphatic polyisocyanate is used, so that the ND filter by light when using the ND filter for a long period of time Of yellowing can be reduced.

  (B) Examples of the aliphatic polyisocyanate include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate. 3-methyl-1,5-pentane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate; isophorone diisocyanate, methylene bis (4 -Cyclohexyl isocyanate), norbornane diisocyanate, cyclohexyl diisocyanate, etc. Aneto and the like.

Among these, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, isophorone diisocyanate, norbornane diisocyanate, and cyclohexyl diisocyanate are preferable.
These polyisocyanate compounds can be used alone or in combination of two or more.

  As the polyol used as the component (c), ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,3-butanediol, cyclohexanedimethylol, Tricyclodecane dimethylol, 1,6-hexanediol, 2-butyl-2-ethyl-propanediol; polyether polyol having alkyleneoxy structure; polyol having bisphenol structure; polycaprolactone diol; polyester diol; polycarbonate diol; Can be mentioned.

Among these, a polyether polyol having an alkyleneoxy structure and a polyol having a bisphenol structure are preferable.
Examples of the polyether polyol having an alkyleneoxy structure include polyethylene glycol, polypropylene glycol, polybutylene glycol, polyethylene butylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol; ethylene oxide, propylene oxide , Butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl Ether, allyl glycidyl carbonate Obtained by ring-opening copolymerization of two or more of ion-polymerizable cyclic compounds such as butadiene monooxide, isoprene monooxide, vinyl oxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenylglycidyl ether, butyl glycidyl ether, and glycidyl benzoate. Polyether diols; and the like. Of these, polypropylene glycol, polybutylene glycol, polyethylene butylene glycol, and polytetramethylene glycol are preferred.

In addition, it is preferable that the polyether polyol which has an alkyleneoxy structure used as (c) component has a number average molecular weight calculated | required in polystyrene conversion of 500 or more, and it is preferable that it is 900 or more.
Examples of the polyol having a bisphenol structure include bisphenol A polyethoxyglycol, bisphenol A polypropoxyglycol, bisphenol A polyethoxypropoxyglycol, bisphenol F polyethoxyglycol, bisphenol F polypropoxyglycol, bisphenol F polyethoxypropoxyglycol, and bisphenol S poly. Examples thereof include ethoxy glycol, bisphenol S polypropoxy glycol, and bisphenol S polyethoxy propoxy glycol.

The urethane (meth) acrylate as the component (A) is produced, for example, by the following methods (1) to (4).
(1) A method in which (c) a polyol and (b) an aliphatic polyisocyanate are reacted, and then (a) a hydroxyl group-containing (meth) acrylate is reacted.
(2) A method in which (b) an aliphatic polyisocyanate and (a) a hydroxyl group-containing (meth) acrylate are reacted, and then (c) a polyol is reacted.
(3) A method in which (c) a polyol, (b) an aliphatic polyisocyanate, and (a) a hydroxyl group-containing (meth) acrylate are charged together and reacted.
(4) A method in which (b) an aliphatic polyisocyanate and (a) a hydroxyl group-containing (meth) acrylate are reacted, then (c) a polyol is reacted, and finally (a) a hydroxyl group-containing (meth) acrylate is reacted.

Of these, the method (2) is preferably used.
When producing the urethane (meth) acrylate of component (A), usually, copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin dilaurate, triethylamine, triethylenediamine-2-methyltriethyleneamine, etc. The urethanization catalyst is used in an amount of 0.01 to 1% by mass based on the total amount of the reaction raw materials. The reaction temperature is usually 10 to 90 ° C, particularly 30 to 80 ° C.

  (A) The number average molecular weight of urethane (meth) acrylate is preferably 500 to 20,000, more preferably 1,000 to 15,000. When the number average molecular weight is less than 500, the adhesiveness of the light attenuating layer obtained by curing the curable resin composition to the substrate is lowered. Conversely, when the number average molecular weight exceeds 20,000, the curability is decreased. There may be a problem that the viscosity of the resin composition becomes high and the handling becomes difficult.

  The component (B) used in the radiation curable resin composition of the present invention is an ethylenically unsaturated group-containing compound that does not contain an alicyclic structure other than the component (A). Examples of the component (B) include compounds containing a (meth) acryloyl group or a vinyl group (hereinafter referred to as “unsaturated monomer”).

As the unsaturated monomer, a monofunctional monomer and a polyfunctional monomer can be used.
Examples of the monofunctional monomer include vinyl monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, vinylimidazole, and vinylpyridine; phenoxyethyl (meth) acrylate, phenoxy-2-methylethyl (meth) acrylate, phenoxyethoxyethyl (meta ) Acrylate, 3-phenoxy-2-hydroxypropyl (meth) acrylate, 2-phenylphenoxyethyl (meth) acrylate, 4-phenylphenoxyethyl (meth) acrylate, 3- (2-phenylphenyl) -2-hydroxypropyl ( (Meth) acrylate, (meth) acrylate of p-cumylphenol reacted with ethylene oxide, 2-bromophenoxyethyl (meth) acrylate, 2,4-dibromophenoxyethyl (meth) acrylate , 2,4,6-tribromophenoxyethyl (meth) acrylate, phenoxy (meth) acrylate, polyoxyethylene nonylphenyl ether (meth) acrylate, 2-hydroxyethyl modified with plural moles of ethylene oxide and propylene oxide (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth ) Acrylate, amyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isoamyl (meth) acrylate, hexyl (meth) Acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) Acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, polyethylene Glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, methoxyethylene glycol (meth) acrylate Ethoxyethyl (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, diacetone (meth) acrylamide, isobutoxymethyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, t-octyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 7-amino-3,7-dimethyloctyl (meth) acrylate, N, N-diethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, hydroxybutyl building ether, lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether and the like can be mentioned.

Among these, phenoxyethyl (meth) acrylate, polyoxyethylene nonylphenyl ether (meth) acrylate, and the like are preferable.
Multifunctional monomers include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol Di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylol Propanetrioxyethyl (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, tris (acryloyloxy) isocyanurate, Pentaerythritol hexa (meth) acrylate, di (meth) acrylate of diol which is an adduct of polyethylene oxide or propylene oxide of bisphenol A, di (meth) of diol which is an adduct of ethylene oxide or propylene oxide of hydrogenated bisphenol A Examples thereof include acrylate, epoxy (meth) acrylate obtained by adding (meth) acrylate to diglycidyl ether of bisphenol A, and triethylene glycol divinyl ether.

  Among these, dipentaerythritol hexa (meth) acrylate, tripropylene glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, di (meth) of diol which is an adduct of polyethylene oxide or propylene oxide of bisphenol A Acrylate and the like are preferable.

In addition, as (B) component, it becomes possible to adjust hardness and a refractive index suitably by using together and using a monofunctional monomer and a polyfunctional monomer.
The (meth) acrylate having an alicyclic structure as the component (C) is a monofunctional monomer such as isobornyl (meth) acrylate, bornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, dicyclopentanyl (meth) acrylate. , Dicyclopentenyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, acryloylmorpholine, imide acrylate and the like. Examples of the polyfunctional monomer include ECH-modified hexahydrophthalic acid diacrylate, bis (hydroxymethyl) tricyclodecane di (meth) acrylate, and tricyclodecane dimethanol acrylate.
The component (C) can obtain good adhesion particularly when a resin having an alicyclic skeleton is used as the transparent resin substrate.

  In addition to the components (A) to (C), when ultraviolet rays are used as active energy rays, it is also preferable to further add a photopolymerization initiator. Any photopolymerization initiator may be used as long as it initiates polymerization by generating radicals by light (active energy rays). For example, acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2- Dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-dimethoxybenzophenone, 4,4'-diaminobenzophenone Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl dimethyl ketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, -Hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino- Propan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis- (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, and the like.

  As a commercially available product of the curable resin component suitable in the present invention, OPSTAR KZ9457 (manufactured by JSR) is preferable. Opstar KZ9457 has good adhesion to transparent resin substrates, particularly cyclic olefin resin substrates, and has a low shrinkage during curing and a small difference in refractive index from the transparent resin, so that the shape stability of the ND filter is improved. It is preferable because it is excellent in moldability and can prevent reduction in resolution, image ghosting and flare.

  The active energy ray means, for example, ionizing radiation such as infrared rays, visible rays, ultraviolet rays and X rays, electron rays, α rays, β rays, and γ rays. Usually, light such as ultraviolet rays is easily used. Often used.

  The addition amount of the photopolymerization initiator is preferably 0.01 to 10% by weight, particularly preferably 0.5 to 7% by weight, with the total amount of the curable resin composition being 100% by weight. When the blending ratio of the photopolymerization initiator is less than 0.01% by mass, the curing rate may decrease and the reaction efficiency may decrease. On the other hand, when the blending ratio of the photopolymerization initiator exceeds 10% by mass, the curing characteristics and handleability of the curable resin composition, and the mechanical characteristics and optical characteristics of the cured product may be inferior.

In addition, a photosensitizer can be mix | blended with the resin composition of this invention with a photoinitiator as needed.
Examples of the photosensitizer include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. Etc.

  Furthermore, in addition to the above components, various additives as necessary include, for example, antioxidants, ultraviolet absorbers, light stabilizers, silane coupling agents, coating surface improvers, thermal polymerization inhibitors, leveling agents, surfactants. , Coloring agents, storage stabilizers, plasticizers, lubricants, mold release agents, solvents, fillers, anti-aging agents, wettability improvers and the like can be blended as necessary.

<Pigment>
The pigment used in the present invention is a pigment having absorption in the visible light region and is not particularly limited as long as it has a uniform absorption in the visible light region, but carbon black, metal oxide, metal nitride. And at least one kind of inorganic particles selected from metal nitride oxides are preferable, and the inorganic particles are more preferably inorganic ultrafine particles.

It is desirable that the pigment is contained in the light attenuating layer in an amount of about 0.01 to 5% by weight, preferably about 0.05 to 3% by weight with respect to 100% by weight of the curable resin composition.
It is preferable that the light attenuating layer contains the pigment in the above-described ratio because it can absorb light moderately in the visible light region and easily produce an ND filter having a desired optical density.

  The metal oxide, metal nitride, and metal nitride oxide having absorption in the visible light region may be any metal oxide, nitride, and nitride oxide, but 3 to 4 in the fourth period of the element periodic table. It is preferably composed of oxides, nitrides and nitrides of metals belonging to Group 11. The group 3 to 11 of the fourth period of the periodic table include scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), Nickel (Ni) and copper (Cu) belong, and among these, Ti, Mn, Fe and Cu are preferable. Furthermore, the metal oxide is preferably a composite oxide composed of two or more metals, and particularly preferably a metal composite oxide composed of copper, iron, and manganese. The composition ratio of the metal composite oxide composed of copper, iron, and manganese is not particularly limited, but when the metal composite oxide composed of copper, iron, and manganese is 100% by weight, the copper oxide is 5%. A metal composite oxide having a composition ratio of ˜30 wt%, iron oxide of 25 to 70 wt%, and manganese oxide of 25 to 70 wt% is preferable.

  Since the spectral transmittance curve in the visible light region of the composite metal oxide composed of oxides of copper, iron, and manganese having the above composition ratio has flatness, the above composition ratio of copper An ND filter using a metal complex oxide composed of oxides of iron, manganese and the like is preferable because it shows a flat spectral transmittance curve in the visible light region.

  The primary particle diameter of the carbon black, metal oxide, metal nitride, metal nitride oxide and metal composite oxide is 5 to 100 nm, preferably 20 to 70 nm. By setting the primary particle diameter within this range, there is an effect of suppressing scattered light of the ND filter. This is preferable because the resolution reduction of the ND filter, image ghosting, and flare can be prevented.

  In the present invention, the primary particles of the pigment in the curable layer may be dispersed as they are, or the added primary particles may be aggregated and dispersed as secondary, tertiary or higher aggregated particles. The primary particles and the aggregated particles of secondary particles or more may be mixed and dispersed. In any case, the average particle diameter of the particles in the light attenuation layer is preferably about 50 to 600 nm, more preferably about 50 to 400 nm, and even more preferably about 50 to 200 nm. It is preferable to use a pigment having such an average particle diameter because the haze value of the ND filter can be lowered.

≪Dye≫
The dye used in the present invention is not particularly limited as long as it is a dye having absorption in the visible light region.
In the case of using an organic dye, it has absorption at a specific wavelength due to its chemical structure. Therefore, in the present invention, when the spectral transmittance curve of the ND filter is not flattened only by containing a specific pigment in the light attenuating layer, it is absorbed in the wavelength region of A part of FIG. 7 showing an example of the spectral transmittance curve. The spectral transmittance curve of the ND filter can be flattened by including a specific dye having a azo group in the light attenuation layer together with the pigment.

  Examples of the dye having absorption in the visible light region include phthalocyanine-based, thiol metal complex-based, azo-based, polymethine-based, diphenylmethane-based, triphenylmethane-based, quinone-based, anthraquinone-based, and diimonium salt-based dye compounds. is there.

  Examples of commercially available dyes having absorption in the visible light region suitable for the present invention include SDA4137, SDA4428, SDA9800, SDA9811, SDB3535 (manufactured by SANDS), KAYASORB series, and Kayset series (manufactured by Nippon Kayaku). It is done.

≪Other ingredients≫
Moreover, in the range which does not impair the objective of this invention, additives, such as antioxidant and a ultraviolet absorber, can further be added in curable resin composition.

  Examples of the antioxidant include 2,6-di-t-butyl-4-methylphenol, 2,2′-dioxy-3,3′-di-t-butyl-5,5′-dimethyldiphenylmethane, And tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane.

  Examples of the ultraviolet absorber include 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone. Moreover, when manufacturing an ND filter by the solution casting method mentioned later, the manufacture can be made easy by adding a leveling agent and an antifoamer.

The addition amount of these additives is appropriately selected according to the desired properties, but is usually 0.01 to 5.0% by weight, preferably 0.00%, with respect to 100% by weight of the curable resin composition. It is desirable that it is 05-2.0 weight%.
≪ND filter structure≫
The ND filter of the present invention is not particularly limited as long as it has a structure having different optical densities in a single ND filter by having light attenuation layers of different thicknesses in a single ND filter. A structure as shown in FIG.

Here, “optical density” refers to a measure of the transmittance of light passing through the ND filter.
When the ND filter has a structure as shown in the following diagram, it is preferable in that an ND filter having a desired optical density can be easily manufactured.

  (A) FIG. 1 shows an example of an ND filter when the thickness of the light attenuation layer 2 changes partially or stepwise. FIG. 2 shows the thickness of the light attenuation layer 2 continuously changing. An example of the ND filter in the case of performing is shown.

When the ND filter has the structure shown in FIGS. 1 and 2, it is particularly preferable in that an ND filter having a desired optical density can be easily designed and manufactured.
(A) FIG. 3 illustrates an example of the ND filter when the thickness of the transparent resin substrate 1 changes partially or stepwise, and FIG. 4 illustrates the thickness of the transparent resin substrate 1 continuously changing. An example of the ND filter in the case of performing is shown.

  When the ND filter has the structure as shown in FIGS. 3 and 4, the surface has few irregularities, so that the ND filter itself is scratched or when the ND filter of the present invention is used in an imaging device. This is preferable in that it can prevent other members used together with the ND filter from being damaged.

  (C) FIG. 5 shows a roll 4 having a non-smooth surface after a curable resin composition containing a pigment and / or dye is applied on the transparent resin substrate 1 to form a curable layer 3. 4 is an ND filter formed by irradiating an active energy ray or the like from the transparent resin substrate 1 side to cure the curable layer 3 when transferring the surface shape 4 to the curable layer 3.

  Here, the “curable layer” refers to a layer formed by applying a curable resin composition containing a pigment and / or a dye on a transparent resin substrate, and refers to a layer before being cured. . A layer obtained by curing the curable layer is referred to as a light attenuation layer.

The “roll having a non-smooth surface” refers to a roll having a function of transferring a concavo-convex pattern or the like to an object such as an embossing roll.
In the case where the ND filter has the structure as shown in FIG. 5, in particular, molding and curing can be performed simultaneously, which is excellent in terms of efficiency of ND filter production and mass production.

  (D) FIG. 6 shows a second transparent resin layer whose thickness has been changed in advance after a curable resin composition containing a pigment and / or dye is applied on the transparent resin substrate 1 to form a curable layer 3. 6 was overlapped with the side having a change in thickness directed toward the curable layer 3, and the curable layer 3 was cured by irradiating active energy rays or the like from the transparent resin substrate 1 side in the overlapped state. ND filter.

  Here, the “second transparent resin layer” is a layer different from the transparent resin substrate, and is a layer having at least two different thicknesses in the same layer and made of a transparent resin. . The transparent resin may be the same as the transparent resin used for the substrate, or may be a different resin.

Further, irradiation with active energy rays or the like may be performed from the transparent resin substrate 1 side or from the second transparent resin layer 6 side.
When the ND filter has the structure as shown in FIG. 6, it has the same characteristics as the above (A), and is particularly preferable in terms of prevention of warpage of the ND filter and excellent durability.

[ND filter manufacturing method]
In the present invention, the production method of the ND filter is not particularly limited, but for example, the ND filter can be produced by the following method.

  The ND filter according to the present invention can be produced by applying a curable resin composition containing a pigment and / or a dye to the transparent resin substrate produced by the above production method and irradiating active energy rays. it can.

  As the step (1) of forming a curable layer comprising a curable resin composition containing a pigment and / or a dye on a transparent resin substrate having a substantially constant thickness and at least two types of transparent resin substrates, Various methods such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing are adopted. be able to.

Moreover, methods, such as a press method and a casting method, can be used as a process (2) which forms the light attenuation layer from which thickness differs on the transparent resin substrate which has substantially constant thickness.
As a pressing method, for example, a curable resin composition is dropped on flat quartz, and a transparent resin substrate having a different thickness is placed on the curable resin composition with the different thickness sides facing the flat quartz side. Further, flat quartz is placed on a surface of a transparent resin substrate having a different thickness (hereinafter referred to as a sandwiching method), and after applying heat and light while maintaining horizontal, at least upper and lower flat quartz is removed. It is possible to obtain an ND filter having light attenuation layers having two kinds of thickness.

  Producing ND filters in this way facilitates thinning of ND filters, and is highly adaptable to production volume adjustments, design changes, etc., and has fewer steps, improving productivity and yield. This is particularly preferable.

  Further, as the step (2), a mold having a desired light attenuation layer shape is used, a curable resin composition is poured between the mold and the transparent resin substrate, and irradiation with active energy rays or the like is performed. The curable resin composition can also be cured. When the light attenuation layer is formed by such a method, the light attenuation layer can be produced in a short time, and it is preferable from the viewpoint of excellent productivity.

  Moreover, as said process (2), after apply | coating and hardening a curable resin composition on a transparent resin substrate with the said application | coating method, apply | coating and hardening further a curable resin composition to a part on the light attenuation layer. By doing so, it is also possible to form light attenuation layers having partially different thicknesses on the transparent resin substrate. By repeating such a process, light attenuation layers having different thicknesses can be formed in stages.

  In addition to this, as the step (2), after applying a curable resin composition on a transparent resin substrate to form a curable layer, the surface shape of the roll is adjusted using a roll having a non-smooth surface. There is a method for producing an ND filter by curing the curable layer when transferring to the curable layer (FIG. 5).

Such a production method can perform molding and curing simultaneously, and is excellent in terms of efficiency and mass production of ND filter production.
Moreover, as said process (2), after apply | coating the said curable resin composition on a transparent resin board | substrate and forming a curable layer, the 2nd transparent which gave the change to thickness beforehand on the curable layer A method may be used in which the ND filter is manufactured by overlapping the resin layer with the side having a change in thickness facing the curable layer, and curing the curable layer in the overlapped state (FIG. 6).

The ND filter manufactured by such a manufacturing method is preferable in that it is difficult to be damaged, prevents warpage, and has excellent durability.
In addition, in order to improve the adhesiveness between the transparent resin substrate and the light attenuation layer, the surface of the transparent resin substrate may be treated in advance. Examples of the surface treatment include chemical treatment, mechanical treatment, corona treatment, flame treatment, ultraviolet irradiation treatment, high frequency treatment, glow discharge treatment, active plasma treatment, laser treatment, mixed acid treatment, and ozone oxidation treatment.

Curing of the curable layer is not particularly limited, and can be appropriately adjusted by a method known in the art depending on the composition of the curable resin composition to be used, the thickness of the curable resin composition, and the like.
≪Antireflection treatment≫
It is preferable to perform antireflection treatment on at least one surface of the ND filter because stray light, ghost, and the like of the ND filter can be prevented. Further, it is preferable to perform an antireflection treatment on at least one surface of the ND filter because an ND filter having uniform transmittance characteristics can be obtained over the entire wavelength range of the visible light region.

  Specifically, in addition to the method using a known dielectric multilayer film, the nanoimprinting by hot stamping provides an antireflection performance in the visible range, and 0.1 μm from the surface layer of the molded body is fluorinated in fluorine gas. A dielectric multilayer film formed by vapor deposition, a single antireflection layer made of fluorine compound or hollow silica by wet coating, and an antireflection layer made of a plurality of layers having different refractive indexes. It is preferably used to provide antireflection performance by laminating.

  When the molded product is made into a chip by punching or the like and incorporated into an imaging device or the like, the generation of chips generated during cutting is often a big problem, but vacuum evaporation is a means for providing the above-mentioned antireflection performance. By using this method, the generation of chips can be reduced. Furthermore, when productivity is taken into consideration, the surface layer fluorination method enables simultaneous processing of the front and back of the molded body, or treatment with an antireflection layer consisting of a single layer by wet coating, which has excellent reproducibility and high processing speed. Is more preferable.

≪Processing of reflected light on steps and non-vertical surfaces≫
When the optical density is changed by changing the thickness discontinuously with the ND filter, the boundary has a step, and in some cases, the step portion may affect the light receiving element. For this reason, it is also preferable to appropriately perform a process for reducing the influence on the imaging device on the stepped portion.

  Specifically, the cross-section of the step portion is given a shape other than a simple right-angled shape, and when the step portion is viewed from directly above, a corrugated shape such as a curve other than a straight line, or a saw blade-like shape is given. In addition, there is a method of continuously changing the shape of the stepped portion. Alternatively, in order to eliminate the step, the entire surface of the ND filter including the step is coated with a transparent resin in the visible range, and the edge portion of the step is filled with the transparent resin. There is a method that eliminates a significant step.

  Further, it is preferable to separately prepare a transparent molded body having a shape that is paired with the step shape of the ND filter, and to bond the surfaces with the step so that the step is completely eliminated.

  In addition, the ND filter of the present invention may have a portion of the incident surface of the ND filter that cannot be at least perpendicular to the light incident axis (this surface is hereinafter referred to as a non-perpendicular surface).

  The light that passes through the air and reaches the non-vertical surface of the ND filter is refracted by the transmitted light, and reflected light is reflected in a direction different from the incident light. There arises a problem of generating stray light due to reflection.

Therefore, as a solution, the incident surface of the ND filter after bonding the transparent resin is bonded to the non-vertical surface by bonding the molded transparent resin described above and adjusting the shape of the transparent resin as appropriate. Both exit surfaces can be perpendicular to the incident light.
[Method of adjusting light transmittance]
The method for adjusting the light transmittance of the present invention is not particularly limited, but the light transmitted through the ND filter by moving a single ND filter having a different optical density in a direction orthogonal to the incident light. The transmittance of light transmitted through the ND filter is adjusted by rotating the ND filter whose optical density is changed in the circumferential direction by adjusting the transmittance of the ND filter. be able to.

Further, when the ND filter of the present invention is used in an imaging device such as a digital camera or a digital still camera, the ND filter of the present invention has different optical densities in a single ND filter, and thus the in-plane variable light attenuation performance. Performance can be provided and the light transmittance can be adjusted. Therefore, it is possible to drastically improve the performance of imaging devices such as digital cameras and digital still cameras at low cost.
[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

Transmission characteristics by wavelength The light transmittance by wavelength in the range of 450 to 650 nm was measured using a Hitachi spectrophotometer U-3310 (manufactured by Hitachi, Ltd.).

Adhesiveness According to JISK5400, a 5 × 5 cross-cut peel test was performed, and the adhesiveness was determined according to the following criteria.
A: No peeling of the curable resin composition after curing was observed in all 25 squares
○: Partial peeling of the curable resin composition after curing was observed at 1-5 squares in 25 squares x: Complete peeling of 1 square or more in 25 squares or partial peeling of 6 squares or more was observed .

Environmental test The thermal shock test of the following conditions was implemented 200 cycles.
Low temperature condition: −40 ° C. × 30 minutes High temperature condition: + 85 ° C. × 30 minutes [Preparation Example 1] Preparation of Curable Resin Composition (1) Ketjen Black EC-600JD (Ketjen 0.12 parts by weight of Black International Co., Ltd.), 100 parts by weight of silicone resin LPS-L500 (manufactured by Shin-Etsu Chemical Co., Ltd.), and 50 parts by weight of zirconia beads (0.1 mm in diameter) are added, and a paint shaker (Red Devil) And carbon black was uniformly dispersed in the silicone resin.

  The dispersion after dispersion is passed through a stainless steel mesh (the number of holes is 200 per inch square), the zirconia beads are removed, and the filtrate from which the zirconia beads are further removed is filtered through a PTFE 5-micron membrane filter and cured. Resin composition (1) was obtained.

[Preparation Example 2] Preparation of curable resin composition (2) Dipyroxide TM Black # 3550 (manufactured by Dainichi Seika Kogyo Co., Ltd.) which is a metal composite oxide (metal species is composed of copper, iron and manganese) as a pigment A curable resin composition (2) was obtained in the same manner as in Preparation Example 1 except that 0.4 part by weight was used.

[Preparation Example 3] Preparation of Curable Resin Composition (3) Curability was the same as in Preparation Example 1 except that 0.22 parts by weight of TBX-02 (Ishihara Sangyo Co., Ltd.), which is titanium nitride, was used as the pigment. A resin composition (3) was obtained.

[Preparation Example 4] Preparation of curable composition (4) A curable resin composition was prepared in the same manner as Preparation Example 1 except that 0.25 parts by weight of Tilac D (manufactured by Ako Kasei Co., Ltd.), which is titanium oxide, was used as a pigment. A product (4) was obtained.

[Preparation Example 5] Preparation of curable composition (5) Take 1.3 g of DispersBYK-167 (Active ingredient 52%, manufactured by Big Chemie) in a plastic bottle and add 24.2 g of methyl ethyl ketone (MEK) to it. Mix well, add 4.5 g of the above-mentioned Dipyroxide TM Black # 3550 as a pigment, add 10 g of zirconia beads (0.1 mm in diameter), and disperse with a paint shaker (manufactured by Red Devil) for 6 hours. Then, using a stainless mesh (with 500 holes per square inch), remove the zirconia beads, and then filter the filtrate from which the zirconia beads have been removed with a PTFE 5-micron membrane filter to obtain a solid content concentration. A 21% by weight metal oxide dispersion was obtained. 0.16 g of this metal oxide dispersion and 5.84 g of OPSTAR KZ9457 (manufactured by JSR) were placed in a brown bottle and stirred for 2 hours in a 70 ° C. water bath with a magnetic stirrer to obtain a curable resin composition (5). Obtained.

[Preparation Example 6] Preparation of curable composition (6) Instead of using 5.84 g of OPSTAR KZ9457 (manufactured by JSR), 2.92 g of OPSTAR KZ9457 (manufactured by JSR) and an acrylate having an alicyclic structure A curable resin composition (6) was obtained in the same manner as in Preparation Example 5 except that 2.92 g of NK ester A-DCP (manufactured by Shin-Nakamura Chemical Co., Ltd.) was used.

[Preparation Example 7] Preparation of curable composition (7) 20 g of the curable composition (6) obtained in Preparation Example 6 was weighed into a brown bottle, and Kayase Orange-A-N (Nippon Kayaku Co., Ltd.) was used as a dye. (Product made) 0.006g was added and it stirred with the magnetic stirrer in the 70 degreeC water bath for 2 hours, and obtained the curable resin composition (7).

[Preparation Example 1] Preparation of a step film (1) An acrylic film, Technoloy S-013 (manufactured by Sumitomo Chemical Co., Ltd .; thickness 125 microns), and a nickel mold whose cross-sectional shape is convex (step difference 70 microns) is used as a film. On the other hand, a concave step of 70 microns was given to the film surface by a hot press method in which the mold was pushed in parallel. The stepped shape transferred to the film had good followability to the mold. After the film was cut out at 2 cm square so as to include the concave portion, corona treatment was performed on the surface having a step under the condition of 0.1 W / m ² / min in the atmosphere to obtain a step film (1).

[Preparation Example 2] Preparation of a step film (2) A nickel mold having a convex shape (step difference of 70 microns) on an ARTON R50 (manufactured by JSR; thickness 150 microns) is a transparent film made of a cyclic olefin polymer. A concave step of 70 microns was applied to the film surface by a hot press method in which a mold was pressed in parallel with the film. The stepped shape transferred to the film had good followability to the mold. After the film was cut out at 2 cm square so as to include the concave portion, corona treatment was performed on the surface having a step under the condition of 0.2 W / m ² / min in the atmosphere to obtain a step film (2).

[Production Example 3] Production of wedge-shaped thickness change film (3) A nickel mold having a wedge-shaped cross section (one step is no step and the height is 70 microns on one side) is used in the above-mentioned ARTON R50 (thickness 150 microns). Then, a wedge-shaped thickness change was applied to the film surface by a hot press method. The wedge shape transferred to the film had good followability to the mold. After the film is cut out in a 2 cm square so as to include a wedge-shaped portion, a corona treatment is performed on the surface having a wedge-shaped thickness change under the condition of 0.2 W / m ² / min in the atmosphere, and a wedge-shaped thickness change film (3) was obtained.

[Example 1] Manufacture of ND filter (1) 0.1 milliliter of the curable resin composition (1) prepared in Preparation Example 1 was dropped on flat quartz, and the step film (1) prepared in Preparation Example 1 was added thereon. ) Place the stepped surface on the curable resin composition with the stepped quartz side facing the flat quartz side, and then place 2 cm square size (thickness 2 mm) flat plate quartz on the stepless surface of the stepped film (hereinafter sandwiched) This is referred to as a method.) While maintaining the horizontal state at 80 ° C. for 20 hours, the upper and lower plate quartzs were removed to obtain an ND filter (1) having two types of light attenuation layers.
The evaluation results of the ND filter (1) are shown in Table 1.

[Examples 2 to 8] Production of ND filters (2) to (8) ND filters (2) to (8) were prepared in the same manner as in Example 1 using the curable resin composition and substrate shown in Table 2. Obtained.
In Examples (2), (4), (6), and (8), the temperature was maintained at 130 ° C. for 5 hours.
The evaluation results of the ND filters (2) to (8) are shown in Table 1.

[Example 9] Manufacture of ND filter (9) 70% of the stepped film (2) prepared in Preparation Example (2) using the curable resin composition (5) prepared in Preparation Example 5 was 70. After coating using a film applicator with a micrometer so as to have a coating thickness of micron, it is cured by irradiation with a high-pressure mercury lamp (peak illuminance 0.25 W / cm ² , integrated light quantity 0.5 J / cm ² ). An ND filter (9) having a light attenuation layer with a thickness of 5 mm was obtained. The evaluation results of the ND filter (9) are shown in Table 1.

[Example 10] Manufacture of ND filter (10) A curable layer was prepared by the same sandwiching method as in Example 1 by combining the curable resin composition (5) and the step film (2). By curing under the same curing conditions, an ND filter (10) having a light attenuation layer having two thicknesses was obtained. The evaluation results of the ND filter (10) are shown in Table 1.

[Example 11] Production of ND filter (11) A curable layer was prepared by the same sandwiching method as in Example 1 by combining the curable resin composition (6) and the step film (2). By curing under the same curing conditions, an ND filter (11) having a light attenuation layer having two thicknesses was obtained. The evaluation results of the ND filter (11) are shown in Table 1.

[Example 12] Manufacture of ND filter (12) A curable layer was prepared by the same sandwiching method as in Example 1 by combining the curable resin composition (6) and the wedge-shaped thickness change film (3). The ND filter (12) having a light attenuation layer whose thickness was changed continuously by curing under the same conditions as in No. 9 was obtained. The evaluation results of the ND filter (12) are shown in Table 1.

[Example 13] Manufacture of ND filter (13) The curable resin composition (6) prepared in Preparation Example 6 was applied to a transparent resin substrate (ARTON R50 having a thickness of 100 microns) having a thickness of 110 microns on an A4 size smooth surface. The roll is applied using a film applicator with a micrometer so that the coated surface is in contact with a roll having a non-smooth surface having a gear-like cross section, and the non-coated surface is in contact with a roll having a smooth surface. The gap between them was laminated to 160 microns. When passing through this gear-like roll, a high-pressure mercury lamp (peak illuminance 0.5 W / cm ² , integrated light amount 1 J / cm ² ) is irradiated to cure the curable layer, and a film having a light attenuation layer of two types of thickness ND filter (13) was obtained. The evaluation results of the ND filter (13) are shown in Table 1.

[Example 14] Manufacture of antireflection (AR) -treated ND filter (14) The ND filter obtained in Example 11 was subjected to AR treatment by vacuum deposition on both sides of the film under the following conditions (an AR layer was provided). ) And an ND filter (14) was obtained. The evaluation results of the ND filter (14) are shown in Table 1. The reflectance of the ND filter (14) after the AR treatment is shown in FIG. In the ND filter (14) in which the ND filter (11) was subjected to antireflection treatment, the reflectance was lower than that of the ND filter (11), and the transmittance characteristics were more uniform in the visible light region.

AR treatment conditions While performing ion assist, the deposition source was melted with an electron gun, and an AR film was formed by vacuum deposition.
When the thickness of each layer was confirmed by cross-sectional TEM, the following values were obtained.
(From the light attenuation layer side)
High refractive index layer (TiO ₂ layer); 0.02 μm
Low refractive index layer (SiO ₂ layer); 0.03 μm
High refractive index layer (TiO ₂ layer); 0.11 μm
Low refractive index layer (SiO ₂ layer); 0.08 μm
(From the transparent resin substrate side)
High refractive index layer (TiO ₂ layer); 0.06 μm
Low refractive index layer (SiO ₂ layer): 0.01 μm
High refractive index layer (TiO ₂ layer); 0.10 μm
Low refractive index layer (SiO ₂ layer); 0.09 μm

[Example 15] Production of AR-treated ND filter (15) using pigment and dye together A curable layer was prepared by the same sandwiching method as in Example 1 except that the curable resin composition (7) was used. Then, an ND filter having two types of light attenuation layers was prepared by curing under the same curing conditions as in Example 9, and AR treatment was performed on both sides of the ND filter in the same manner as in Example 14, A filter (15) was obtained. The evaluation results of the ND filter (15) are shown in Table 1.
The ND filter (15) treated with AR using a pigment and a dye together showed low reflectance and more uniform transmittance characteristics in the visible light region.

[Example 16] Manufacture of chip-shaped ND filter (16) The ND filter (9) obtained in Example 14 was cut out with a punching machine under the following conditions. A chip-shaped ND filter (16) having a clean cut surface that was not obtained was obtained. A schematic diagram of the ND filter (16) after cutting is shown in FIG. 9, and a cross-sectional photograph of the ND filter (16) is shown in FIG.

Punching conditions Punching was performed with a Thomson blade using a punching machine MP-250SL (manufactured by Sakai Machine Industry Co., Ltd.).

[Example 17] Light amount adjustment using an ND filter having light attenuation layers of two types of thickness The ND filter (16) obtained in Example 16 was incorporated in a camera module.
The camera module applies light directly to the light receiving element without passing through the ND filter, or applies light transmitted through a portion where the light attenuation layer of the ND filter is thin to the light receiving element. Further, the light attenuation of the ND filter By irradiating the light-receiving element with light transmitted through a portion having a thick layer, it becomes possible to capture an image with an appropriate exposure amount according to the change in the brightness of external light.

[Comparative Example 1] Light amount adjustment using an ND filter having only one type of light attenuation layer The ND filter (16) obtained in Example 16 is cut off from the portion where the light attenuation layer is thin, and is used as a camera module. Incorporated.

  The camera module picked up the light by directly applying light to the light receiving element without passing through the ND filter, or by applying light transmitted through the ND filter to the light receiving element. In the middle case, it was not possible to take an image with an appropriate exposure amount.

Table 1 is a table | surface which shows the light transmittance and adhesiveness of ND filter of Example 1-15.
In Table 1, the low optical density indicates the transmittance when the light transmittance at a wavelength of 450 to 650 nm is measured at an arbitrary point in the portion where the thickness of the light attenuation layer of the ND filter of each example is thin. High refers to the transmittance when the light transmittance at a wavelength of 450 to 650 nm is measured at an arbitrary point in the thick portion of the light attenuation layer of the ND filter of each example.
Table 2 is a table | surface which shows the manufacturing conditions of ND filter of Example 1-15.

FIG. 1 illustrates an example of an ND filter when the thickness of the light attenuation layer 2 changes partially or stepwise. FIG. 2 illustrates an example of the ND filter when the thickness of the light attenuation layer 2 continuously changes. FIG. 3 illustrates an example of the ND filter when the thickness of the transparent resin substrate 1 changes partially or stepwise. FIG. 4 illustrates an example of the ND filter when the thickness of the transparent resin substrate 1 continuously changes. FIG. 5 shows a case in which a curable resin composition containing a pigment and / or dye is applied on a transparent resin substrate 1 to form a curable layer 3 (left figure), and then the roll 4 having a non-smooth surface is used. When transferring the surface shape of the roll 4 to the curable layer 3, it is an ND filter formed by irradiating an active energy ray from the transparent resin substrate 1 side and curing the curable layer 3 (right figure). FIG. 6 shows a second transparent resin whose thickness has been changed in advance after a curable resin composition containing a pigment and / or dye is applied to the transparent resin substrate 1 to form a curable layer 3 (left figure). The layer 6 was formed by superimposing the side having a change in thickness toward the curable layer 3, irradiating active energy rays from the transparent resin substrate 1 side in the superimposed state, and curing the curable resin 3. It is an ND filter (right figure). FIG. 7 shows an example of a spectral transmittance curve. FIG. 8 is a diagram showing the reflectance of each wavelength of the ND filter (14). FIG. 9 is a schematic diagram of the ND filter (16). FIG. 10 is a cross-sectional photograph of the step portion of the ND filter (16).

Explanation of symbols

1: transparent resin substrate 2: light attenuation layer 3: curable layer 4: roll 5 having a non-smooth surface: second transparent resin layer A: maximum value of light transmittance in visible light region (T _max) ) Near wavelength region B: Wavelength region near the minimum value (T _min ) of light transmittance in the visible light region 7: In the ND filter (16) In the portion where the light attenuation layer is thick 8: In the ND filter (16) Thin portion of light attenuation layer 9: AR layer 10: Light attenuation layer 11: Transparent resin substrate

Claims (17)

On a transparent resin substrate, it has a light attenuation layer formed from a curable resin composition containing a pigment and / or a dye,
The ND filter, wherein the light attenuation layer has at least two kinds of thicknesses.   The ND filter according to claim 1, wherein the thickness of the light attenuation layer is changed partially, stepwise, or continuously.   The ND filter according to claim 1, wherein the transparent resin substrate has a substantially constant thickness.   The ND filter according to claim 1 or 2, wherein the transparent resin substrate has at least two kinds of thicknesses.   The ND filter according to claim 4, wherein the thickness of the transparent resin substrate is changed partially, stepwise, or continuously.   The ND filter according to claim 1, wherein at least one surface of the transparent resin substrate is further subjected to an antireflection treatment. The transparent resin substrate is made of a cyclic olefin polymer having a structural unit derived from a monomer containing at least one compound represented by the following formula (1). ND filter according to the above.

[In the formula (1), x represents 0 or an integer of 1 to 3, and y represents 0 or 1.
R ^{1 to} R ⁴ each independently represents one selected from the following (i) to (v), or (vi) or (vii).
(I) a hydrogen atom,
(Ii) a halogen atom,
(Iii) polar group,
(Iv) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms having a linking group containing an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom;
(V) a substituted or unsubstituted hydrocarbon group having 1 to 15 carbon atoms,
(Vi) R ¹ and R ² , or R ³ and R ⁴ represent an alkylidene group formed by bonding to each other, and R ^{1 to} R ⁴ not participating in the bonding are independently of each other, Represents one selected from (i) to (v),
(Vii) an aromatic ring or a non-aromatic monocyclic or polycyclic carbocyclic ring formed by bonding R ¹ and R ² , R ³ and R ⁴ , or R ² and R ³ to each other; R ^{1 to} R ⁴ which represent a heterocyclic ring and are not involved in the bond are independently selected from the above (i) to (v). ] At an arbitrary point, the average value of the light transmittance at a wavelength of 450 to 650 nm is T _ave (%), the minimum value of the light transmittance is T _min (%), and the maximum value of the light transmittance is T _max (%). The ND filter according to claim 1, wherein these satisfy the following formulas (2), (3), and (4):
T _ave ≦ 70 (2)
0.85 × T _ave ≦ T _min (3)
1.15 × T _ave ≧ T _max (4)   The ND filter according to claim 1, wherein the pigment contains at least one inorganic particle selected from carbon black, metal oxide, metal nitride, and metal nitride oxide.   The ND filter according to claim 1, wherein the pigment is a metal composite oxide composed of copper, iron, and manganese oxides.   The ND filter according to claim 1, wherein the curable resin composition is a composition that is cured by active energy rays.   The ND filter according to claim 1, wherein the curable resin composition contains (meth) acrylate having an alicyclic structure. A step (1) of forming a curable layer comprising a curable resin composition containing a pigment and / or a dye on a transparent resin substrate;
Curing the curable layer to form a light attenuating layer having at least two thicknesses (2),
A method for producing an ND filter, comprising:   In the step (2), after the curable layer is formed, the curable layer is cured when the surface shape of the roll is transferred to the curable layer using a roll having a non-smooth surface. The method for producing an ND filter according to claim 13.   After the step (2) forms the curable layer, the second transparent resin layer that has been changed in thickness in advance on the curable layer is directed toward the curable layer on the side where the thickness is changed. The method for producing an ND filter according to claim 13, wherein the curable layer is cured in a superposed state.   An ND filter manufactured by the manufacturing method according to claim 13.   A method for adjusting light transmittance using the ND filter according to claim 1.

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