JP5333261B2 - Polarization diffraction element - Google Patents

Abstract

An object of the invention is to provide a polarization diffraction element which has high light use efficiency and high industrial production performance, high optical characteristic and high in-plane uniformity. The polarization diffraction element of the invention is provided with a pattern part with a dent part and a projection part that are formed continuously and a filling part for filling the dent part on a substrate formed by transparent resin, wherein one in the projection part and the filling part is made of optical isotropic material, and the other is made of optical anisotropic material. Furthermore the formulae (i) and (ii) are satisfied: (i) 0.008<=[absolute value of (Nu(lambda1)-No(lambda1))]<=0.012, and (ii) 0.004<=[absolute value of (Nu(lambda2)-No(lambda2))]<=0.009, (lambda1: linear polarized light with a wavelength of 660nm, lambda2: linear polarized light with a wavelength of 785nm, Nu: refractive index of optical isotropic material, and No: ordinary refractive index of optical anisotropic material).

Description

  The present invention relates to a polarizing diffraction element that can be used in an optical system such as an optical pickup device capable of recording or reproducing information with respect to an optical recording medium such as an optical disk.

  An optical disk device is an optical information recording / reproducing device that has been greatly expanded in recent years due to non-contact, a large amount of information per unit volume, high-speed accessibility, low cost, etc., taking advantage of these features, Various recording media have been developed. For example, information can be written only once with a laser, such as a compact disc (CD), laser disc (LD), CD-ROM, DVD-ROM, etc. that reproduces pre-recorded information as sound, images or computer programs. Optical pickup devices have been developed that are compatible with magneto-optical disks (MO), DVD-RAM, DVD-RW, and the like that can repeatedly record and reproduce information, such as CD-R and DVD-R that can reproduce information.

  In such an optical system of an optical pickup device, various optical components are incorporated and used in order to reduce the size and performance of the device. For example, lasers, diffraction gratings, wave plates, half mirrors, polarizing diffractive elements, objective lenses, and the like that are light sources are examples of typical components.

Among these components, the polarizing diffractive element is an optical component for blocking so-called return light that transmits laser light, which is linearly polarized light, in the forward path but not in the return path.
As a polarizing diffraction element, a diffraction grating is conventionally formed on a glass substrate or a plastic substrate (see Patent Documents 1 and 2) or an organic birefringent film formed on an optically isotropic substrate. What is formed (see Patent Documents 3 and 4) is known.

  In these polarizing diffraction elements, the refractive index difference, which is the difference between the refractive index of the isotropic material of the diffraction grating and the ordinary refractive index of the anisotropic material, is almost zero. In the polarizing diffraction element, when the refractive index difference is 0, there is an advantage that the transmittance can be maximized and the wavefront aberration can be minimized.

  On the other hand, in the manufacture of a polarizing diffraction element, there may be a large in-plane variation in optical characteristics. In general, the polarization diffraction element is manufactured in a size having an area of several square centimeters or more and is cut (chip cut product) into a size of several square millimeters. If there is a large variation in the in-plane optical characteristics of transmittance and wavefront aberration in a state of being manufactured with an area of several square centimeters or more, there is a problem that the final chip-cut product includes inferior optical characteristics. It is necessary to inspect all products to remove this. Here, if there is little variation in in-plane optical properties of the polarizing diffraction element and the optical properties of the entire surface are uniform, the resulting chip-cut product will not be mixed with inferior optical properties. It is expected that productivity will be greatly improved. For this reason, there is a need for a polarizing diffraction element with small in-plane variation and uniform optical characteristics over the entire surface.

The conventional polarizing diffraction elements are all manufactured through a photolithography process and an etching process.
However, when manufactured through a photolithography process or an etching process, only a single-wafer substrate can be used as a substrate due to device limitations. For this reason, since it can be produced only by so-called batch processing, continuous productivity is poor. In addition, the photolithography process and the etching process are based on the premise that there is a material that can be removed by photoresist or etching, and the manufacturing process of the polarizing diffractive element is complicated. There was a problem.

Japanese Patent Laid-Open No. 11-64615 JP-A-11-125710 JP 2003-43254 A Japanese Patent Laid-Open No. 2003-50312

  An object of the present invention is to provide a polarizing diffraction element having high light utilization efficiency, high industrial productivity, and high in-plane uniformity of optical characteristics.

  As a result of intensive research in view of the above prior art, the present inventors have found that there is a slight difference between the refractive index of the isotropic material of the diffraction grating and the ordinary light refractive index of the anisotropic material in the polarizing diffraction element. It has been found that by controlling to such a specific range, in-plane uniformity can be improved by suppressing in-plane variations in optical characteristics (transmittance and wavefront aberration), and the present invention has been completed.

That is, the polarizing diffraction element of the present invention has a diffraction grating layer formed of an optically isotropic material and an optically anisotropic material on at least one surface of a transparent substrate,
It is characterized by satisfying the following formulas (i) and (ii).
(I) 0.008 ≦ | Nu (λ ₁ ) −No (λ ₁ ) | ≦ 0.012
(Ii) 0.004 ≦ | Nu (λ ₂ ) −No (λ ₂ ) | ≦ 0.009
[In the formulas (i) and (ii),
λ ₁ : linearly polarized light having a wavelength of 660 nm,
λ ₂ : linearly polarized light having a wavelength of 785 nm,
Nu (λ ₁ ): refractive index of optically isotropic material at wavelength λ ₁
No (λ ₁ ): ordinary light refractive index of optically anisotropic material at wavelength λ ₁ ,
Nu (λ ₂ ): refractive index of optically isotropic material at wavelength λ ₂ ,
No (λ ₂ ): Represents the ordinary refractive index of the optically anisotropic material at the wavelength λ ₂ . (However, the refractive index and the ordinary light refractive index are measured values at 25 ° C.) Here, the ordinary light refractive index means a refractive index corresponding to ordinary light propagating in a direction perpendicular to the optical axis of the anisotropic material. To do. ]

  In the polarizing diffraction element of the present invention, the diffraction grating layer has a pattern portion in which a concave portion and a convex portion are continuously formed, and a filling portion formed by filling the concave portion, and the concave portion and the convex portion. It is preferable that either one of the pattern portion formed continuously with the filling portion and the filling portion is made of an optically isotropic material, and the other is made of an optically anisotropic material. In such a polarizing diffraction element of the present invention, the pattern part in which the concave part and the convex part are continuously formed is made of an optically anisotropic material, and the filling part is made of an optically isotropic material, or the concave part is made. The pattern part in which the convex part and the convex part are continuously formed may be made of an optically isotropic material, the filling part may be made of an optically anisotropic material, and the concave part and the convex part are continuously formed. It is also preferable that the formed pattern portion is formed by transfer.

In the polarizing diffraction element of the present invention, the transparent substrate is preferably made of a resin.
In the polarizing diffraction element of the present invention, the transparent resin is preferably made of a cyclic olefin resin.

In the polarizing diffraction element of the present invention, it is preferable that a layer having molecular orientation ability is formed on the surface of the base material made of a transparent resin on which the diffraction grating layer is formed.
In the polarizing diffraction element of the present invention, the optically anisotropic material preferably contains an ultraviolet curable liquid crystal.

In the polarizing diffraction element of the present invention, the optically isotropic material preferably contains an ultraviolet curable (meth) acrylic resin.
The polarizing diffraction element of the present invention preferably has an antireflection layer on at least one surface, and preferably further satisfies the following formulas (iii) to (vi) or (vii) to (x).
(Iii) To (λ ₁ ) ≧ 95%
(Iv) To (λ ₂ ) ≧ 95%
(V) Te (λ ₁ ) ≦ 5%
(Vi) Te (λ ₂ ) ≦ 15%
(Vii) To (λ ₁ ) ≧ 95%
(Viii) To (λ ₂ ) ≧ 95%
(Ix) Te (λ ₁ ) ≦ 15%
(X) Te (λ ₂ ) ≦ 5%
[In the formulas (iii) to (vi)
λ ₁ : linearly polarized light having a wavelength of 660 nm,
λ ₂ : linearly polarized light having a wavelength of 785 nm,
To (λ ₁ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₁ ,
To (λ ₂ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₂ ,
Te (λ ₁ ): extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the direction of the extraordinary light refractive index of the optically anisotropic material at wavelength λ ₁ ,
Te (λ ₂ ): represents the extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the extraordinary light refractive index direction of the optically anisotropic material at the wavelength λ ₂ . ]

  According to the present invention, when the polarizing diffraction element satisfies the above formulas (i) and (ii), the polarizing property has high light utilization efficiency, high industrial productivity, and excellent in-plane optical property uniformity. A diffractive element can be provided. Since the polarizing diffraction element of the present invention is excellent in in-plane uniformity of optical characteristics (transmittance and wavefront aberration), a chip-cut product manufactured using the same does not include defective products inferior in optical characteristics. It is possible to omit the inspection of all chip-cut products, and the production efficiency can be greatly improved.

FIG. 1 shows the base material (a′-3) of Example 3 of the present invention. FIG. 2 shows a polarizing diffraction element according to Example 3 of the present invention. FIG. 3 shows the base material (a′-1) of Example 1 of the present invention. FIG. 4 shows a polarizing diffraction element according to Example 1 of the present invention. FIG. 5 shows a method for manufacturing a polarizing diffraction element according to Example 5 of the present invention. FIG. 6 shows a polarizing diffraction element according to Example 5 of the present invention.

Hereinafter, the present invention will be specifically described.
The polarizing diffraction element of the present invention has a diffraction grating layer formed of an optically isotropic material and an optically anisotropic material on at least one surface of a transparent substrate. The diffraction grating layer is not particularly limited as long as a portion made of an optically anisotropic material acts as a diffraction grating, and preferably, a concave portion and a convex portion are continuously formed. It has a pattern part and a filling part formed by filling the concave part, and either the pattern part in which the concave part and the convex part are continuously formed, or the filling part is made of an optically isotropic material. The other is made of an optically anisotropic material.

Base Material The base material used in the present invention may be transparent, and glass, resin, a composite material of glass and resin, etc. can be used, and it is preferably plate-shaped or film-shaped. The substrate may be formed from only one layer or may be formed from multiple layers. Moreover, it is also preferable that a base material has a layer which has molecular orientation ability.

The transparent substrate used in the present invention is preferably made of resin.
The transparent resin constituting the substrate can be used without particular limitation as long as it is transparent at the laser wavelength when using the polarizing diffraction element obtained by the production method of the present invention. The ratio is preferably 85% or more, more preferably 87% or more, and most preferably 89% or more.

  As such a transparent resin, for example, a thermoplastic resin such as triacetyl cellulose (TAC), PMMA, PS, PC, PES, PSU, or cyclic olefin resin, an ultraviolet curable resin, or the like can be used.

  As the transparent resin, a thermoplastic resin is usually used, but an ultraviolet curable resin having an appropriately prepared structure can also be used. As the ultraviolet curable resin, for example, an ultraviolet curable (meth) acrylic resin described later can be used.

  Among these, as the transparent resin, a cyclic olefin resin is preferable from the viewpoints of heat resistance, durability, and processability. As a cyclic olefin-type resin, the glass transition temperature (Tg) used as the parameter | index of a heat deformation temperature is 90-200 degreeC normally, Preferably it is 100-190 degreeC, More preferably, it is 110-180 degreeC. A Tg of 110 ° C. or higher is preferable because the obtained polarizing diffraction element has excellent heat resistance. When Tg is less than 90 ° C., the heat distortion temperature becomes low, which may cause a problem in heat resistance, and a problem that a change in optical characteristics due to temperature in the obtained film becomes large may occur. is there. On the other hand, when Tg exceeds 200 ° C., the processing temperature becomes too high, so that when the film is processed into a film shape, coloring due to oxidative degradation may occur, resulting in a problem that optical characteristics are deteriorated.

  Here, the glass transition temperature (Tg) is the maximum peak temperature of the differential differential scanning calorimetry curve obtained when measured in a nitrogen atmosphere using a differential scanning calorimeter (DSC) at a heating rate of 20 ° C./min ( A point) and a temperature of −20 ° C. from the maximum peak temperature (B point) are plotted on the differential scanning calorimetry curve, and the intersection of the tangent line on the baseline starting from B point and the tangent line starting from A point Desired.

  The base material made of the transparent resin may be in the form of a single wafer or may have a long shape in the longitudinal direction. The so-called roll shape having a long shape in the longitudinal direction is more preferable from the viewpoint of continuous productivity, but it is also preferable to cut the shape of the sheet after forming the roll shape. In addition, since the base material according to the present invention is made of a transparent resin, it is softer than a glass substrate or a crystal substrate and can be easily formed into a roll shape, and is easy to process such as punching into a desired shape. This is preferable. As a method of processing into such a roll shape, a molding method such as extrusion molding of a transparent resin or a solution casting method can be used. When the roll shape is used, the width of the substrate is not particularly limited, but in view of industrial handling, it is preferably 150 to 2200 mm, and more preferably 300 to 1500 mm. When the width is narrower than 150 mm, it is not preferable from the viewpoint of economical productivity, and when the width is wider than 2200 mm, the apparatus used for manufacturing becomes large and becomes inefficient as actual production. Further, the thickness of the substrate is not particularly limited as long as the form as an optical component can be maintained, but in the case of a roll shape, it is preferably 30 to 500 μm, more preferably 50 to 300 μm, and most preferably 80. ~ 200 μm. If the thickness is less than 30 μm, the rigidity as a base material is weak, which is not preferable. If the thickness exceeds 300 μm, it is difficult to form a roll shape, and the winding length when the roll shape is formed is shortened. Therefore, it is not preferable because continuous productivity is lowered. On the other hand, if the thickness exceeds 300 μm, it is not preferable from the viewpoint that burrs or cracks are likely to occur during processing such as punching. In the case of a single wafer, the width and length are preferably 3 to 100 cm, more preferably 5 to 80 cm in view of industrial handling. Note that the width and the length do not need to match, and may be set to a size that can be easily processed. For example, when the A4 size is used to form a single wafer, the size is 21 cm × 30 cm. In the case of a single wafer, if the width and length are less than 3 cm, it is not preferable because industrial productivity is lacking, and if the width and length exceeds 100 cm, the apparatus becomes large and lacks workability. On the contrary, it is not preferable because productivity becomes poor.

  The substrate made of a transparent resin that can be used in the present invention may be formed only of the transparent resin, but improves the adhesion between the substrate and the diffraction grating layer, for example, on the transparent resin substrate. It is also preferable that a primer layer or a layer having molecular orientation ability (hereinafter also referred to as an orientation layer) is formed. The layer having molecular orientation ability may be formed on one side of the transparent resin base material, or may be formed on both sides, but is preferably formed on the surface on which a pattern portion described later is formed.

Layer with molecular orientation (alignment layer)
The layer having molecular orientation is usually a composition (B) containing at least one selected from (meth) acrylic compounds, polyimide, polyvinyl alcohol and polyurethane, and a polymer having a structure represented by the following formula (I) Formed by the composition (B ′) containing

—R ¹ —CH═CH—Z ¹ —Ar ¹ (I)
[In the formula (I), R ¹ is 1,4-phenylene having a group selected from —C (O) O—, —CONH—, —CO—E—, unsubstituted or halogen, cyano and nitro. Or alternatively represents pyridine-2,5-diyl, pyrimidine-2,5-diyl, 2,5-thiophenediyl, 2,5-furylene, 1,4-naphthylene, or 2,6-naphthylene,
E is unsubstituted or 1,4-phenylene having a group selected from a halogen group, a cyano group and a nitro group, or pyridine-2,5-diyl, pyrimidine-2,5-diyl, 2,5-thiophenediyl, 2 , 5-furanylene, 1,4-naphthylene, or 2,6-naphthylene,
Z ¹ is a single bond, unsubstituted or 1,4-phenylene having a group selected from a halogen group, a cyano group and a nitro group, or pyridine-2,5-diyl, pyrimidine-2,5-diyl, 2,5- Represents thiophenediyl, 2,5-furanylene, trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl or 1,4-piperidyl;
Ar ¹ represents a monovalent group having an aromatic ring. ]

  As the composition (B) containing the (meth) acrylic compound, a (meth) acrylic resin obtained using the same material as the (meth) acrylic compound that can be used in an optically isotropic material described later is used. Even if it contains, the composition containing a (meth) acrylic-type compound and a photoinitiator may be sufficient. In addition, as a photoinitiator, the thing similar to what can be used in the case of hardening of the optically isotropic material can be used. A (meth) acrylic compound is used as an optically isotropic material, which will be described later, but a film obtained from a composition containing the compound can also be used as a layer having molecular orientation ability by rubbing treatment or stretching treatment. Is possible. When the base material made of a transparent resin is a cyclic olefin resin, the layer having molecular orientation ability includes a monofunctional monomer or polyfunctional monomer containing an alicyclic structure, particularly from the viewpoint of adhesion to the base material. Is preferred.

  Monofunctional monomers containing the alicyclic structure include cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclo Examples thereof include pentenyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecanyl (meth) acrylate, and the like, including many alicyclic structures. Examples of the functional monomer include tricyclodecanediyldimethyldi (meth) acrylate.

  Examples of the layer-forming composition (B) having molecular orientation ability including polyimide include those obtained by dehydrating and cyclizing polyamic acid obtained by reacting tetracarboxylic dianhydride and diamine. Examples of the alcohol include modified polyvinyl alcohol obtained by replacing the hydroxyl group of polyvinyl alcohol with an organic group, and examples of the polyurethane include a polymer obtained by reacting a polyether polyol and a polyisocyanate.

As the layer-forming composition (B) having a molecular orientation ability containing polyvinyl alcohol, the hydroxyl group of polyvinyl alcohol is 0.2 mol% in terms of substituent —OCOPhO (CH ₂ ) ₄ OCOCH═CH ₂ , and substituent —OCOCH _3. 5 weight parts of a modified polyvinyl alcohol powder having a saponification degree of 88 mol% and a polymerization degree of 300 having a structure substituted with 11.8 mol% was mixed with 100 parts by weight of distilled water, and 35 parts by weight of methanol was added. The dissolved one can be listed.

  Examples of the layer-forming composition (B) having molecular orientation ability including polyurethane include polyether polyurethane. As a commercially available product of such a polyurethane resin, Hydran WLS-201 (manufactured by DIC Corporation), which is a polyether polyurethane material, can be mentioned.

The layer having molecular orientation ability is preferably formed from a composition containing a (meth) acrylic compound in terms of adhesion to the substrate.
Moreover, as another component contained in the composition containing at least one selected from (meth) acrylic compounds, polyimide, polyvinyl alcohol and polyurethane, adhesion to the surface of the substrate within a range not impairing the intended physical properties. From the viewpoint of further improving the properties, a functional silane-containing compound, an epoxy compound, or the like may be contained.

  The polymer having the structure represented by the formula (I) is not particularly limited. For example, the polymer having the formula (I) in the side chain is disclosed in, for example, JP-A Nos. 2003-307736 and 6-287453. Examples thereof include those described in polyimide polymers and acrylic polymers. In addition, as other components contained in the composition containing the polymer having the structure represented by the formula (I), from the viewpoint of improving the adhesiveness to the surface of the substrate described above within a range not impairing the target physical properties. , Functional silane-containing compounds, epoxy compounds and the like may be contained.

  When the substrate has a layer having molecular orientation ability, the thickness of the layer having molecular orientation ability is preferably 1 to 5000 nm, more preferably 5 to 500 nm, and most preferably 10 to 200 nm.

<Method of imparting molecular orientation ability>
When the layer having molecular orientation ability is composed of a composition (B) containing at least one selected from (meth) acrylic compounds, polyimide, polyvinyl alcohol, and polyurethane, the layer was formed from the composition (B). The coating film (B) is preferably given molecular orientation ability by any method of rubbing treatment and stretching treatment.

(1) Method by rubbing treatment The rubbing treatment can be performed by a known method. For example, a composition (B) containing at least one selected from a (meth) acrylic compound, polyimide, polyvinyl alcohol and polyurethane is used. A coating film (B) is formed on the substrate by coating on the substrate, and a surface of the coating film is wound around a metal roll surface by wrapping a rubbing cloth such as cotton or rayon, and rotating the roll. And a treatment for imparting molecular orientation. Although it does not specifically limit as a process condition of a rubbing process, 100-2000 rpm is preferable, as for a roll rotation speed, More preferably, it is 200-1500 rpm, Most preferably, it is 300-900 rpm. 1-50 m / min is preferable and, as for the conveyance speed of the base material in which the coating film was formed, 3-30 m / min is more preferable. The roll push-in amount is preferably 0.1 to 0.5 mm, more preferably 0.2 to 0.4 mm.

  When performed under the above processing conditions, a uniform rubbing process can be performed over the entire surface of the coating film (B), so that a layer having molecular orientation can be suitably formed. The rubbing direction is determined by the angle formed by the rotation axis direction of the rubbing roll and the longitudinal direction of the film (the substrate on which the coating film (B) is formed), but if the rubbing roll can cover the entire film width, There is no particular limitation. Since the rubbing direction determines the alignment direction of the liquid crystal molecules, the rubbing treatment may be performed by setting the rubbing direction to a desired direction.

  In the rubbing process, foreign matter may be generated. This is because the fibers of the rubbing cloth have fallen off, the film surface material used for rubbing has been scraped off and the surrounding environmental foreign matter adheres due to the generated static electricity. Accordingly, it is necessary to remove these foreign substances, and it is preferable to blow out the foreign substances and suck them or to wash them. Of these, washing with water is preferably used. In particular, the coating film (B) formed by applying the polyimide-containing composition (B) is highly resistant to water due to the polyimide structure, and will be described later without damaging the rubbing effect even if washed with water. This is preferable because the optically anisotropic material can be oriented. Moreover, since the coating film (B) formed by applying the composition (B) containing at least one selected from polyvinyl alcohol and polyurethane is washed with water, the polyvinyl alcohol and polyurethane have low resistance to water. Since it becomes impossible to orient the optically anisotropic material mentioned later, it is not preferable to perform washing with water. In addition, when modified polyvinyl alcohol having a crosslinked structure is used as polyvinyl alcohol, or when modified polyurethane such as a polymer obtained by reacting a polyether polyol having a crosslinked structure and polyisocyanate is used as polyurethane, the crosslinked structure Since the resistance to water is expressed, the coating film (B) formed by applying the composition (B) containing polyvinyl alcohol and polyurethane will be described later without impairing the rubbing effect even if washed with water. An optically anisotropic material can be oriented.

When the layer having molecular orientation ability is composed of a composition (B ′) containing a polymer having a structure represented by the above formula (I), molecular orientation is imparted by irradiation with radiation such as ultraviolet rays and visible rays. It is preferred that

(2) Method by stretching treatment The molecular orientation ability is imparted by subjecting a base material made of a transparent resin having a coating film (B) formed by the layer forming composition (B) having the molecular orientation ability. May be.

  A layer forming composition (B) having molecular orientation ability by stretching a substrate made of a transparent resin having a coating film (B) formed by the layer forming composition (B) having molecular orientation ability. The coating film (B) formed by (1) can be given molecular orientation ability, and the optically anisotropic material formed on the layer can be oriented.

  The stretching treatment is usually performed by heating and stretching a coating film (B) formed of a base material made of a transparent resin and a layer forming composition (B) having molecular orientation ability. Heat stretching is preferred because it produces less foreign matter and can be produced with a higher yield than the rubbing treatment.

  As the stretching treatment, a method of stretching a coating film (B) formed of a transparent resin base material and a layer forming composition (B) having molecular orientation ability in the longitudinal direction under heating (stretching treatment) Method (1)) and a method of stretching a coating film (B) formed of a base material and a layer forming composition (B) having molecular orientation ability uniaxially in the width direction under heating (stretching treatment method (2 )) Is preferred.

  When stretching the coating film (B) formed of the base material made of transparent resin and the layer forming composition (B) having molecular orientation ability, the heating temperature at the time of stretching is the base material made of transparent resin and It is preferable that the entire stretched portion of the coating film (B) formed by the layer forming composition (B) having molecular orientation ability is precisely controlled. For example, in the uniaxial stretching in the longitudinal direction in the stretching treatment method (1), that is, longitudinal uniaxial stretching, the temperature distribution is within the set temperature ± 0.6 ° C., preferably within the set temperature ± 0.4 ° C., more preferably the set temperature. It is desirable to carry out in an oven controlled within ± 0.2 ° C.

  Here, the set temperature may be equal in all regions in the oven, or may be a temperature in which distribution is provided stepwise or in a gradient manner. When the set temperature is a temperature having a distribution, the actual temperature distribution in the oven and the set temperature distribution are within ± 0.6 ° C., preferably within ± 0.4 ° C., more preferably It is desirable to be within ± 0.2 ° C.

  The set temperature of the stretching method (1) is that the coating film (B) formed by the base material made of a transparent resin and the layer forming composition (B) having molecular orientation ability is the kind of raw material, the stretching ratio and the stretching speed. The thickness of the base material and the layer having molecular orientation ability, the desired retardation of the optically anisotropic material after stretching, etc. may be set. Although not particularly limited, for example, the base material made of a transparent resin The range is from (Tg + 0) ° C. to (Tg + 30) ° C. based on the glass transition temperature (Tg) of the transparent resin. In such a temperature range, the coating film (B) formed of the transparent resin base material and the layer forming composition (B) having molecular orientation ability is stretched without thermal deterioration and without breaking. This is preferable because it is possible.

  In the said extending | stretching process method (1), the draw ratio of longitudinal direction uniaxial stretching is 1.1-2.5 times, for example, Preferably it is 1.1-2.0 times, Most preferably, it is 1.2-1.5. Double the range. When the draw ratio is less than 1.1 times, the orientation of the optically anisotropic material is not expressed well and is not preferable. When the draw ratio exceeds 2.5 times, the base material breaks during processing. This is not preferable because of problems such as.

The stretching speed of the uniaxial stretching in the longitudinal direction in the stretching method (1) is, for example, in the range of 2 to 100 m / min, preferably 5 to 50 m / min.
The uniaxial stretching in the width direction of the stretching treatment method (2), that is, the lateral uniaxial stretching is performed under temperature control that is more precise than the uniaxial stretching in the longitudinal direction, thereby suitably obtaining a polarizing diffractive element that is homogeneous over the entire surface. be able to. For example, uniaxial stretching in the width direction is performed in an oven in which the temperature distribution is controlled within a set temperature ± 0.5 ° C, preferably within a set temperature ± 0.3 ° C, more preferably within a set temperature ± 0.2 ° C. It is desirable to do it.

  As in the case of the uniaxial stretching in the longitudinal direction, the set temperature of the stretching treatment method (2) may be the same temperature in all regions in the oven, or a temperature in which distribution is provided stepwise or in a gradient manner. Also good. When the set temperature is a temperature having a distribution, the actual temperature distribution in the oven and the set temperature distribution are within ± 0.5 ° C, preferably within ± 0.3 ° C, more preferably It is desirable to be within ± 0.2 ° C. The set temperature in the width direction uniaxial stretching may be the same as or different from the set temperature in the longitudinal direction uniaxial stretching process.

The set temperature of the stretching treatment method (2) is the same as that of the stretching treatment method (1).
In the stretching treatment method (2), the stretching ratio of the uniaxial stretching in the width direction may be determined according to the desired characteristics of the polarizing diffraction element to be produced, and is, for example, 1.5 to 5 times, preferably 1.7. It is -4 times, Especially preferably, it is the range of 2-3.5 times. If the draw ratio is less than 1.5 times, the orientation of the optically anisotropic material is not expressed well and is not preferable. If the draw ratio exceeds 5 times, the base material breaks during processing. Is not preferable.

  The stretching speed of the uniaxial stretching in the width direction is, for example, 2 to 100 m / min, preferably 5 to 50 m / min.

Diffraction grating layer The polarizing diffraction element of the present invention comprises a substrate made of the above-described transparent resin (that is, a substrate made of a transparent resin, or a substrate having a layer having molecular orientation ability formed on a substrate made of a transparent resin). And a diffraction grating layer formed of an optically isotropic material and an optically anisotropic material.

  This diffraction grating layer is composed of a pattern portion and a filling portion, and the pattern portion has portions made of an optically isotropic material and portions made of an optically anisotropic material alternately present in a predetermined pattern. Preferably, the pattern portion in which the concave portion and the convex portion provided on the base material are continuously formed, and the filling portion filling the concave portion are made of one from an optically isotropic material and the other is By forming from an optically anisotropic material, it is desirable that convex portions and filling portions having different optical characteristics are alternately formed, and this becomes a diffraction grating layer.

The pattern portion in which the pattern portion concave portion and the convex portion are continuously formed may be formed from an optically isotropic material or may be formed from an optically anisotropic material.

・ Optical isotropic materials (D)
The optically isotropic material is not particularly limited as long as it is an optically isotropic resin, but may be continuously formed from a composition for forming an optically isotropic material including an ultraviolet curable resin. It is preferable because it is easy to produce a polarizing diffraction element economically, and it is more preferable to contain an ultraviolet curable (meth) acrylic resin from the viewpoint of easily obtaining transparency and optical isotropy.

  As the ultraviolet curable (meth) acrylic resin, a resin obtained by polymerizing the following (meth) acrylate compound is preferably used. The (meth) acrylate compound is not particularly limited as long as it has at least one (meth) acryloyl group in the molecule. For example, as a (meth) acrylate compound, a monofunctional (meth) acrylate compound and a polyfunctional (meth) acrylate compound are mentioned.

  The ultraviolet curable (meth) acrylic resin that can be used in the present invention is cured by ultraviolet rays. Examples of light sources that generate ultraviolet rays include metal halide lamps and high-pressure mercury lamps. In addition, ultraviolet irradiation may be performed from the surface side which forms the pattern of a base material, and may be performed from the surface side which does not form the pattern of a base material. Moreover, when forming a pattern continuously, it is preferable to irradiate ultraviolet rays from the opposite side of the mold, that is, the surface side where the pattern of the base material is not formed, and the mold is made of ultraviolet curable (meth) acrylic resin. You may irradiate from the surface side which does not have a pattern in the state which contacted the containing composition.

  In the present invention, the (meth) acrylate compound refers to at least one compound selected from the group consisting of acrylate compounds and methacrylate compounds, and the (meth) acryloyl group refers to a group consisting of acryloyl groups and methacryloyl groups. At least one group selected is shown.

Specific examples of monofunctional (meth) acrylate compounds include methyl (meth) acrylate, ethyl (meth) acrylate, 2-phenoxyethyl acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and isobutyl. (Meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, amyl (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 Alkyl (meth) acrylates such as rate, dodecyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxy Hydroxyalkyl (meth) acrylates such as butyl (meth) acrylate; phenoxyalkyl (meth) acrylates such as phenoxyethyl (meth) acrylate and 2-hydroxy-3-phenoxypropyl (meth) acrylate;
Alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate;
Polyethylene glycol (meth) acrylates such as polyethylene glycol mono (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate;
Polypropylene glycol (meth) acrylates such as polypropylene glycol mono (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, ethoxypolypropylene glycol (meth) acrylate, nonylphenoxy polypropylene glycol (meth) acrylate;
Cyclohexyl (meth) acrylate, 4-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate Cycloalkyl (meth) acrylates such as dicyclopentadienyl (meth) acrylate, bornyl (meth) acrylate, isobornyl (meth) acrylate, and tricyclodecanyl (meth) acrylate;
Examples include benzyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate and the like. These monofunctional (meth) acrylate compounds can be used individually by 1 type or in mixture of 2 or more types.

  Among these monofunctional (meth) acrylate compounds, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentadienyl (meth) acrylate, etc. In particular, it is preferable because of its excellent adhesion to a substrate made of a transparent resin.

Specific examples of the polyfunctional (meth) acrylate compound include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, 1,4 -Alkylene glycol di (meth) acrylates such as butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate;
Trimethylolpropane tri (meth) acrylate, trimethylolpropane trihydroxyethyl tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa Poly (meth) acrylates of polyhydric alcohols such as (meth) acrylate and hydroxypivalate neopentyl glycol di (meth) acrylate;
Isocyanurate poly (meth) acrylates such as isocyanurate tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate di (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate;
Poly (meth) acrylates of cycloalkanes such as tricyclodecanediyldimethyldi (meth) acrylate;
Di (meth) acrylate of bisphenol A ethylene oxide adduct, di (meth) acrylate of propylene oxide adduct of bisphenol A, di (meth) acrylate of alkylene oxide adduct of bisphenol A, ethylene oxide addition of hydrogenated bisphenol A Di (meth) acrylate, di (meth) acrylate of propylene oxide adduct of hydrogenated bisphenol A, di (meth) acrylate of alkylene oxide adduct of hydrogenated bisphenol A, bisphenol A diglycidyl ether and (meth) acrylic (Meth) acrylate derivatives of bisphenol A such as (meth) acrylate obtained from acids;
3,3,4,4,5,5,6,6-octafluorooctanedi (meth) acrylate, 3- (2-perfluorohexyl) ethoxy-1,2-di (meth) acryloylpropane, Nn Fluorine-containing (meth) acrylates such as -propyl-N-2,3-di (meth) acryloylpropyl perfluorooctylsulfonamide;
Examples thereof include urethane (meth) acrylates obtained by reacting the following polyol (a) having a bisphenol structure, organic polyisocyanate (b), and hydroxyl group-containing (meth) acrylate (c).

  Examples of the polyol (a) having a bisphenol structure include bisphenol A alkylene oxide addition diol, bisphenol F alkylene oxide addition diol, hydrogenated bisphenol A alkylene oxide addition diol, hydrogenated bisphenol F alkylene oxide addition diol, and the like. Can be mentioned. Of these, bisphenol A alkylene oxide addition diols are preferred. As these commercial items, NOF Corporation DA-400, DB-400 etc. are mentioned, for example.

  (B) As organic polyisocyanate, diisocyanate is preferable, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5- Naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'- Biphenylene diisocyanate etc. are mentioned. Among these, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate are particularly preferable.

  (C) Hydroxyl group-containing (meth) acrylates include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 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, dipentaerythritol penta (meth) a And the like can be given Relate. Of these, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like are preferable.

These polyfunctional (meth) acrylate compounds can be used individually by 1 type or in mixture of 2 or more types.
Among these polyfunctional (meth) acrylate compounds, dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, etc. have many acryloyl groups contained in one molecule, and the crosslinking density A polyfunctional (meth) acrylate compound that can improve the thickness and give excellent film hardness is particularly preferred.

・ Photopolymerization initiator (photo radical generator)
When an ultraviolet curable (meth) acrylic resin is used as the optically isotropic material, the (meth) acrylate compound is polymerized (cured), and a photopolymerization initiator (photoradical generator) is used for the polymerization. It is preferable to use it.

  Specific examples of the photopolymerization initiator (photo radical generator) include 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorene, fluorenone, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoylpropyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) -2 -Hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthioxanthone, 2-isopropylthioxyl , 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzyl-2-dimethyl Examples include amino-1- (4-morpholinophenyl) butan-1-one and 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methylpropan-1-one. These photopolymerization initiators (photo radical generators) can be used alone or in combination of two or more.

  Among these photopolymerization initiators (photo radical generators), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide 1-hydroxycyclohexyl phenyl ketone is preferred.

  Moreover, a commercial item can be used for such a photoinitiator (photoradical generator). For example, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one is Irgacure 907 (manufactured by Ciba Specialty Chemicals Co., Ltd.), and 1-hydroxycyclohexyl phenyl ketone is It can be obtained as Irgacure 184 (manufactured by Ciba Specialty Chemicals).

  The addition amount of the photopolymerization initiator (photo radical generator) is not particularly limited as long as the curing reaction proceeds sufficiently, but is usually 0.1 to 20 with respect to 100 parts by weight of the (meth) acrylate compound. Part by weight, preferably 0.5 to 10 parts by weight is desirable. When the addition amount of the photopolymerization initiator (photo radical generator) is less than the lower limit, the curing reaction of the (meth) acrylate compound does not proceed sufficiently, and sufficient hardness may not be obtained. Moreover, when the addition amount of a photoinitiator (photoradical generator) exceeds the said upper limit, the storage stability of an ultraviolet curable (meth) acrylic resin may fall.

  When a pattern part in which concave parts and convex parts are continuously formed on a base material made of a transparent resin is formed using a composition containing the optically isotropic material as described above, a polarizing diffraction element A portion derived from the convex portion of the has optical isotropy.

Optically anisotropic material The optically anisotropic material can be used without particular limitation as long as it is an optically anisotropic material, but a liquid crystal material is preferably used. Among liquid crystal materials, an ultraviolet curable liquid crystal is preferably used from the viewpoint of producing a polarizing diffraction element continuously and economically.

  The ultraviolet curable liquid crystal is not particularly limited, and a nematic liquid crystal or a smectic liquid crystal in which one or more acrylate groups and / or methacrylate groups are introduced can be used.

  Examples of such ultraviolet curable liquid crystals include azoxy liquid crystals, cyanobiphenyl liquid crystals, Schiff liquid crystals, cyanophenyl ester liquid crystals, cyanophenylcyclohexane liquid crystals, benzoic acid phenyl ester liquid crystals, cyclohexanecarboxylic acid phenyl ester liquid crystals. An ultraviolet curable liquid crystal in which one or more acrylate groups and / or methacrylate groups are introduced into a low molecular liquid crystal such as a liquid crystal, a phenylpyrimidine liquid crystal, and a phenyldioxane liquid crystal can be given. These ultraviolet curable liquid crystals may be used alone or in combination of two or more.

  In the case where the pattern portion is formed using an ultraviolet curable liquid crystal as the optically anisotropic material, and the ultraviolet curable liquid crystal itself has fluidity, the ultraviolet curable liquid crystal may be used even if only the ultraviolet curable liquid crystal is used. A mixture may be used, and a solution to which a solvent is added may be used as a composition in order to improve the coating property of the ultraviolet curable liquid crystal. At this time, as a solvent to be used, when a pattern portion is formed on a layer having molecular orientation ability, a solvent that does not impair the molecular orientation is appropriately selected.

  Specifically, the volatilization rate affects the molecular orientation of the optically anisotropic material, and when the volatilization rate is relatively slow, it can be uniformly volatilized within the applied surface, so that uniform molecular orientation and Therefore, it is preferable.

  That is, the molecular orientation of the optically anisotropic material can be controlled by the difference in the boiling point of the solvent used. For example, a solvent having a boiling point of around 40 ° C. such as acetone has a high volatilization rate at the time of drying, so that the molecular orientation can be controlled to be relatively low, and a solvent having a boiling point of around 80 ° C. such as methyl ethyl ketone has a relatively low volatilization rate. Therefore, a decrease in molecular orientation due to latent heat of vaporization can be suppressed, and a high molecular orientation can be controlled. Note that the solvent is preferably volatilized by applying the composition onto a substrate and then volatilizing the solvent by heating or the like, and preferably before the ultraviolet curing. At this time, the addition amount of the solvent is preferably 1 to 500 parts by mass, more preferably 10 to 400 parts by mass, and particularly preferably 20 to 300 parts by mass with respect to 100 parts by mass of the ultraviolet curable liquid crystal.

  In order to obtain a pattern portion in which concave and convex portions made of a composition containing an ultraviolet curable liquid crystal are continuously formed, ultraviolet rays are applied to the coating film formed from the composition containing the ultraviolet curable liquid crystal. It is preferable to carry out ultraviolet curing of the ultraviolet curable liquid crystal to obtain a cured product (polymer) of the ultraviolet curable liquid crystal.

  The heating is performed to align the liquid crystal, but when a solvent is added as a composition containing an ultraviolet curable liquid crystal, the heating is also performed to volatilize the solvent. Although it depends on the type of liquid crystal to be used, the heating temperature is usually preferably higher than the liquid crystal transition temperature. Considering the heat resistance of a substrate made of a transparent resin and a layer having molecular orientation ability, 40 It is preferable to set it as -150 degreeC, More preferably, it is 50-140 degreeC. When forming a pattern part on a layer having molecular orientation ability, if the heating temperature exceeds 150 ° C., the layer having molecular orientation ability may be deformed, which is not preferable. Since orientation cannot be obtained, it is not preferable, and when a solvent is added, the solvent remains without volatilizing, which is not preferable. Moreover, if it is the said temperature range, you may raise heating temperature in steps.

  Moreover, it is preferable that the composition containing an ultraviolet curable liquid crystal is added with a photopolymerization initiator (photo radical generator). As the photopolymerization initiator, the same photopolymerization initiator (photoradical generator) that can be used when polymerizing (curing) the optically isotropic material such as the (meth) acrylate compound described above is used. be able to.

  The addition amount of the photopolymerization initiator (photo radical generator) is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and most preferably 3 parts by mass with respect to 100 parts by mass of the ultraviolet curable liquid crystal. It is as follows. When the addition amount exceeds 10 parts by mass, the influence of the unreacted photopolymerization initiator on the properties of the polarizing diffraction element such as the liquid crystal transition temperature cannot be ignored. In addition, as a composition containing a commercially available ultraviolet curable liquid crystal, for example, Licrivue (registered trademark) RMM727 manufactured by Merck & Co., Inc. may be mentioned.

  Examples of a light source for performing ultraviolet curing include a metal halide lamp and a high-pressure mercury lamp. In addition, although ultraviolet irradiation may be performed from the surface side which has a pattern, and may be performed from the surface side which does not have a pattern, when forming a pattern continuously, a mold contains an ultraviolet curing liquid crystal. You may irradiate from the surface side which does not have a pattern in the state which contacted the composition.

  Polarization diffraction obtained when a pattern part in which a concave part and a convex part are continuously formed on a substrate made of a transparent resin is formed using a composition containing an ultraviolet curable liquid crystal as described above. A portion derived from the convex portion of the element has optical anisotropy.

  The pattern portion in which the concave portion and the convex portion according to the present invention are continuously formed is formed from either the above-described optically isotropic material or optically anisotropic material. The method for forming the pattern portion is not particularly limited, and may be formed by photolithography using a photoresist, etching, or may be formed by transfer. As a method for forming a pattern portion in which concave portions and convex portions are continuously formed by photolithography or etching, a conventionally known method can be appropriately employed.

In this invention, it is preferable that the pattern part in which the recessed part and the convex part were formed continuously was formed by transcription | transfer.
In pattern portion formation by transfer, a composition containing the optically isotropic material or optically anisotropic material described above is applied onto a substrate by transfer, and then a dried coating film is obtained by a process such as heating.

  Specific coating methods include, for example, spin coating, lip coating, comma coating, roll coating, die coating, blade coating, dip coating, bar coating, casting film formation, gravure coating Method and printing method. Among these, from the viewpoint of thickness accuracy and mass productivity, a comma coating method, a gravure coating method, or the like is preferably used.

  The thickness of the coated film including the optically isotropic material or the optically anisotropic material is not particularly limited as long as a desired pattern portion can be provided, but for the purpose of ensuring thickness accuracy, preferably 1 to 30 μm, Preferably it is 1-20 micrometers, Most preferably, it is 1-15 micrometers. The design of the pattern recess depth varies depending on the wavelength of the laser used and the type of material used, but is generally in the range of 1 to 10 μm. Therefore, it is preferable to control the thickness of the applied material within the above-mentioned range because the design can be made economically without using unnecessary materials while ensuring the thickness accuracy. Further, the width of the convex portion and the concave portion of the pattern is such that the width of the convex portion is represented by L and the width of the concave portion is represented by S, the value of L / S is 0.4 ≦ {L / (L + S)} ≦ 0.6 is preferable, and 0.45 ≦ {L / (L + S)} ≦ 0.55 is more preferable. In particular, the case where L = S, that is, the case where the width of the convex portion and the width of the concave portion coincide is particularly preferable.

  Further, the width L of the convex portion is preferably 1 μm ≦ L ≦ 10 μm, more preferably 1 μm ≦ L ≦ 5 μm, and most preferably 1 μm ≦ L ≦ 3 μm. The recess width S is also preferably 1 μm ≦ S ≦ 10 μm, more preferably 1 μm ≦ S ≦ 5 μm, and most preferably 1 μm ≦ S ≦ 3 μm. When the width L of the convex part and the width S of the concave part are selected, it is preferable because a desired polarization diffraction ability can be obtained.

  As a method of providing a pattern portion in which a concave portion and a convex portion are continuously formed on a coating film formed of the composition containing the optically isotropic material or the optically anisotropic material described above, the concave portion and the convex portion are used. A mold in which is continuously formed is preferably used. The material of the mold in which the concave portion and the convex portion are continuously formed is not particularly limited as long as a desired pattern can be produced. However, a metallic material such as nickel, a silicone material, or a transparent material such as synthetic quartz can be used. A thing etc. are used preferably. In addition, in order to improve mold release after being in close contact with the coating film in order to impart a shape, the mold surface on which concave and convex portions are continuously formed has a fluorine-based or silicone-based release economy. It is also preferable to perform a release treatment by coating or the like. The shape of the mold in which the concave and convex portions are continuously formed is not particularly limited as long as a desired pattern such as a flat plate shape or a roll shape can be produced. When the substrate is in the form of a roll, a roll-shaped mold may be used.

  In order to obtain a pattern portion in which concave portions and convex portions made of an optically isotropic material or an optically anisotropic material are continuously formed, an optically isotropic material or an optically anisotropic material is used as described above. It is preferable that the coating film on which a pattern is formed with a composition containing a photopolymerization initiator is irradiated with radiation such as ultraviolet rays to be cured.

Filling portion The polarizing diffraction element of the present invention preferably has a filling portion filled with the concave portion of the pattern portion. The filling portion is formed of an optically anisotropic material when the pattern portion is made of an optically isotropic material, and is formed of an optically isotropic material when the pattern portion is made of an optically anisotropic material. As the optically anisotropic material or optically isotropic material capable of forming the filling portion, those described above as those that can be used for forming the pattern portion can be suitably used.

  The filling portion according to the present invention is a filling portion forming composition comprising an optically anisotropic material or an optically isotropic material and the photopolymerization initiator (photoradical generator) described above that can be used for forming a pattern portion. It is preferable to use a product.

  The filling portion can be suitably formed by applying the filling portion forming composition on the surface having the pattern of the base material, filling the concave portion, and curing it by ultraviolet irradiation or the like, if necessary. In FIG. 2 showing a schematic diagram of an embodiment of the present invention, the filling portion is formed only in the concave portion, but actually, the filling portion is also formed in the upper portion of the convex portion at the same time as filling the concave portion. The composition is applied, and a coating film made of the composition may also be present on the top of the convex portion, and the polarizing diffraction element of the present invention may be in such an embodiment.

The polarizing diffraction element of the present invention is not particularly limited, but it is preferable that the convex portion is made of an optically anisotropic material and the filling portion is made of an optically isotropic material.
In the present invention, a transparent resin constituting the substrate, a layer having molecular orientation ability provided on the substrate as necessary, a pattern portion in which concave portions and convex portions are continuously formed, and a filling portion are formed. As necessary, known additives such as antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, antifoaming agents, surfactants (release agents) are added to the material composition. An agent can be added as long as the effects of the invention are not impaired.

-Antireflection layer The polarizing diffraction element of the present invention usually further has an antireflection layer in order to increase the utilization efficiency of light passing through the element.

  The polarizing diffraction element of the present invention preferably has an antireflection layer. The antireflection layer is formed by applying a thermosetting resin composition or a photocurable resin composition by a known coating method such as gravure coating, die coating, or slot coating, drying as necessary, and then curing. can do. It can also be formed by sputtering or vapor deposition. These layers may be provided on one side of the substrate or on both sides.

  The antireflection layer is usually composed of a low refractive index layer, and may further have a laminated structure of a low refractive index layer and a high refractive index layer to further improve the antireflection performance, and further ensure scratch resistance. Therefore, you may have a hard-coat layer. The lamination order is preferably from the outermost layer side of the polarizing element, preferably in the order of hard coat layer / high refractive index layer / low refractive index layer. If necessary, an intermediate refractive index layer may be provided between the low refractive index layer and the high refractive index layer, or between the hard coat layer and the high refractive index layer.

  Examples of the composition for forming the low refractive index layer and the high refractive index layer include known curable compositions comprising a binder resin, a photopolymerization initiator, and high hardness particles. For example, the binder resin contains at least one epoxy resin, phenol resin, melamine resin, alkyd resin, cyanate resin, acrylic resin, polyester resin, urethane resin, siloxane resin, and the like, The composition for forming a low refractive index layer contains a fluorine-containing compound, and the composition for forming a high refractive index layer is a high refractive index inorganic particle, for example, a metal such as silica, alumina, titania, zirconia, ceria, scandia, magnesium fluoride, etc. Contains oxide particles.

  The refractive index and thickness of the low refractive index layer and the high refractive index layer are used in a known range, but in order to enhance the antireflection effect at the wavelength used, the refractive index of the low refractive index layer (average at 25 ° C., wavelength 589 nm). (Refractive index) is preferably 1.45 or less, and the thickness of the low refractive index layer is preferably 50 to 300 nm. The refractive index of the high refractive index layer (average refractive index at 25 ° C. and wavelength 589 nm) is preferably a refractive index larger by 0.05 or more than the refractive index of the low refractive index layer, and the thickness is 50 to 10, 000 nm is preferable.

Polarizing diffractive element The polarizing diffractive element of the present invention comprises a diffraction grating layer, preferably a pattern part in which concave parts and convex parts are continuously formed, and a diffraction grating layer comprising a filling part filled with the concave parts. It may be formed on one side of a substrate made of a transparent resin, may be formed on both sides, and preferably is formed only on one side. The polarizing diffraction element of the present invention includes a diffraction grating layer in which a diffraction grating layer is alternately formed from an optically isotropic material and an optically anisotropic material, and the diffraction grating layer includes a concave portion and a convex portion. Is formed of a pattern part formed continuously and a filling part formed by filling a concave part, one of the pattern part and the filling part forming the convex part is made of an optically isotropic material, and the other is made of an optical material. Made of anisotropic material.

  In the polarizing diffraction element of the present invention, it is also preferable that the concavo-convex portion formed on one side is sealed with a base material, and an optically isotropic material or an optical anisotropic material is applied to the filling portion together with the sealing base material. Adhesion is improved by UV curing.

  The thickness of the polarizing diffraction element of the present invention is not particularly limited. For example, the polarizing diffraction element can be formed into a film having a thickness of about 60 to 500 μm, more preferably about 100 to 300 μm. Since the thickness can be reduced in this way, the optical component can be reduced in size and weight. In addition to having such a thickness, the polarizing diffraction element of the present invention is made of a resin, so that it is easy to process a die-cut product by punching it into a desired shape. preferable.

The polarizing diffraction element of the present invention has a linearly polarizing light with a wavelength of 660 nm as λ ₁ and a linearly polarizing light with a wavelength of 785 nm as λ ₂ .
Nu (λ ₁ ): refractive index of optically isotropic material at wavelength λ ₁
No (λ ₁ ): ordinary light refractive index of optically anisotropic material at wavelength λ ₁ ,
Nu (λ _2): the refractive index of the optically isotropic material at the wavelength lambda _2, and No (λ _2): ordinary refractive index of the optically anisotropic material at the wavelength lambda ₂ is represented by the following formula (i) and (ii) Meet.
(I) 0.008 ≦ | Nu (λ ₁ ) −No (λ ₁ ) | ≦ 0.012
(Ii) 0.004 ≦ | Nu (λ ₂ ) −No (λ ₂ ) | ≦ 0.009
Further, preferably, the following formulas (i ′) and (ii ′) are satisfied.
(I ′) 0.008 ≦ | Nu (λ ₁ ) −No (λ ₁ ) | ≦ 0.010
(Ii ′) 0.004 ≦ | Nu (λ ₂ ) −No (λ ₂ ) | ≦ 0.007

  In the present invention, the refractive index and the ordinary light refractive index mean measured values at 25 ° C. Here, the optically isotropic material has no anisotropy, so the refractive index has a single value, whereas the optically anisotropic material has a method for light incident perpendicular to the material. Two refractive indexes exist in the line plane. Light propagating in the direction perpendicular to the optical axis is called ordinary light, light propagating in the parallel direction is called extraordinary light, and the refractive index corresponding to ordinary light is ordinary light refraction. The refractive index corresponding to the refractive index and extraordinary light is called the extraordinary light refractive index.

Thus, in the polarization diffraction element of the present invention, the ordinary refractive index of the optically anisotropic material in refractive index Nu (lambda ₁₎ and the wavelength 660 nm (lambda ₁₎ of an optical isotropic material at the wavelength 660 nm (lambda ₁₎ No (lambda _1), and, the ordinary refractive index of the optically anisotropic material in the refractive index Nu optically isotropic material (lambda ₂₎ and the wavelength 785 nm (lambda ₂₎ at a wavelength of _{785nm (λ 2) No (λ} 2) Each have a significant difference in the specific range.

That is, in the polarizing diffraction element of the present invention, Nu (λ ₁ ) and No (λ ₁ ), and Nu (λ ₂ ) and No (λ ₂ ) have a difference in the specific range, and any wavelength. The refractive index of the optically isotropic material and the ordinary light refractive index of the optically anisotropic material are not the same, but have a difference controlled within a specific range. As a result, the absolute value of the transmittance is slightly lower than the case where the difference in refractive index is 0, but the fluctuation width of the refractive index derived from the material can be absorbed in the designed refractive index width. In addition, the optical characteristics (transparency) of the polarizing diffraction element can be made substantially uniform throughout the entire surface.

The above Nu (λ ₁ ) is usually 1.600 to 1.400, preferably 1.550 to 1.450 The above No (λ ₁ ) is usually 1.600 to 1.400, preferably 1.550 to 1.450, and the above Nu (λ ₂ ) is usually 1.600 to 1.400. Preferably, it is 1.550 to 1.450, and the above No (λ ₂ ) is usually 1.600 to 1.400, preferably 1.550 to 1.450. Since the optically anisotropic material and optically isotropic material used for the polarizing diffraction element obtained when each Nu and No are within the above range can be within the range of general liquid crystals and acrylic resins, It is also preferable from the viewpoint of supply stability.

Further, in the present invention, by performing the above refractive index control, the bending rate of the transmitted wavefront of ordinary light at λ ₁ and λ ₂ can be made substantially uniform at a low value over the entire surface of the polarizing diffraction element.
The bending rate of the transmitted wavefront is referred to as transmitted wavefront aberration, and is preferably 25 mλ or less, more preferably 20 mλ or less, and even more preferably 15 mλ or less in the polarizing diffraction element. When the wavefront aberration is larger than 25 mλ, the laser light passing through the polarizing diffraction element is distorted, and this is not preferable because it causes a disk reading failure when incorporated in an optical pickup device.

  The difference between the refractive index of such an optically isotropic material and the ordinary refractive index of an optically anisotropic material is appropriately selected from the types of optically isotropic material and optically anisotropic material that form the convex portion and the filling portion. By doing so, it can be controlled within a desired range.

The polarizing diffractive element of the present invention has the antireflection layer, so that linearly polarized light having a wavelength of 660 nm is λ ₁ , and linearly polarized light having a wavelength of 785 nm is λ ₂ .
To (λ ₁ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₁ ,
To (λ ₂ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₂ ,
Te (λ ₁ ): extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the extraordinary light refractive index direction of the optically anisotropic material at wavelength λ ₁ , and Te (λ ₂ ): wavelength λ ₂ The extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the extraordinary refractive index direction of the optically anisotropic material is preferably expressed by the following formulas (iii) to (vi) or (vii) to (x ), Most preferably within a range satisfying (iii ′) to (vi ′) or (vii ′) to (x ′).
(Iii) To (λ ₁ ) ≧ 95%
(Iv) To (λ ₂ ) ≧ 95%
(V) Te (λ ₁ ) ≦ 5%
(Vi) Te (λ ₂ ) ≦ 15%
(Vii) To (λ ₁ ) ≧ 95%
(Viii) To (λ ₂ ) ≧ 95%
(Ix) Te (λ ₁ ) ≦ 15%
(X) Te (λ ₂ ) ≦ 5%
(Iii ′) To (λ ₁ ) ≧ 98%
(Iv ′) To (λ ₂ ) ≧ 98%
(V ′) Te (λ ₁ ) ≦ 3%
(Vi ′) Te (λ ₂ ) ≦ 10%
(Vii ′) To (λ ₁ ) ≧ 98%
(Viii ′) To (λ ₂ ) ≧ 98%
(Ix ') Te (λ ₁ ) ≤ 10%
(X ′) Te (λ ₂ ) ≦ 3%

The polarizing diffraction element of the present invention can have an arbitrary Te (λ) as long as Nu (λ) and Ne (λ) are set so as to satisfy the following formula (xi).
(Xi) Te (λ) = cos ² [[d (Ne (λ) −Nu (λ)) / λ] / p] × 100
In the above equation, d represents the groove depth of the concavo-convex portion, and p represents the repeated length (pitch) of the concavo-convex portion.

Further, by setting Nu (λ) and No (λ) to satisfy the following formula (xii) and having the above-described antireflection film, To (λ) ≧ 98% can be achieved.
(Xii) | Nu (λ) −No (λ) | ≦ 0.012
In the polarizing diffraction element of the present invention, each average value of To (λ ₁ ), To (λ ₂ ), Te (λ ₁ ), and Te (λ ₂ ) measured at a plurality of measurement points is preferably expressed by the above formula ( iii) to (vi) or (vii) to (x), most preferably in a range satisfying (iii ′) to (vi ′) or (vii ′) to (x ′). However, 95% or more, more preferably 97%, of the values of To (λ ₁ ), To (λ ₂ ), Te (λ ₁ ), and Te (λ ₂ ) at each measurement point measured at a plurality of measurement points. The above satisfies the formulas (iii) to (vi) or (vii) to (x), most preferably (iii ′) to (vi ′) or (vii ′) to (x ′). It is desirable to be in a range that satisfies the range.

In the polarizing diffraction element of the present invention, the average value of the transmitted wavefront aberration at the wavelength λ ₁ measured at a plurality of measurement points is preferably 25 mλ or less, more preferably 20 mλ or less, and even more preferably 15 mλ or less.

  The polarizing diffraction element of the present invention can have high in-plane uniformity. For example, the in-plane uniformity of the optical characteristics according to the evaluation method described in Examples described later is 95% or more, preferably 97% or more. More preferably, it can be 99% or more.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples. Each property was measured and evaluated as follows.

(1) Ordinary light transmittance, extraordinary light transmittance and in-plane uniformity Using RETS-1200VA manufactured by Otsuka Electronics Co., Ltd. in the ordinary light refractive index direction of the optically anisotropic material of the polarizing diffraction element under the condition of a light diameter of 2 mmφ. In contrast, normal light transmittance To (λ) of perpendicular incident light having a polarization plane parallel to the parallel direction and extraordinary light transmittance of perpendicular incident light having a polarization plane parallel to the extraordinary refractive index direction of the optically anisotropic material. Te (λ) was measured at 2500 points at intervals of 2 mm within a square area of 10 cm square, and average values a _o (λ) and a _e (λ) were obtained. From the results of these 2500 measurement points, the in-plane uniformity of ordinary light transmittance and extraordinary light transmittance was determined by the following formula (vii).

X / 2500 × 100 (%) (vii)
[In the formula (vii), X is ordinary light transmittance To (λ ₁ ) ≧ 95%, To (λ ₂ ) ≧ 95%, abnormal light transmittance Te (λ ₁ ) ≦ 5%, and Measurement point satisfying Te (λ ₂ ) ≦ 15% or ordinary light transmittance To (λ ₁ ) ≧ 95%, To (λ ₂ ) ≧ 95%, and abnormal light transmittance Te (λ ₁ ) ≦ 15 % And Te (λ ₂ ) ≦ 5%]

(2) Wavefront aberration Using a laser interferometer R-10 manufactured by Fujinon Co., Ltd., using a laser beam having a wavelength of 656 nm and a light diameter of 2 mmφ, the entire RMS (λrms) as a wavefront aberration of the polarizing diffraction element is a square area of 10 cm square. 100 points were measured at intervals of 10 mm inside to obtain an average value λrms _ave . From the results of these 100 measurement points, points where the measured value was 15 mλ or less were counted, and the number of points was defined as in-plane uniformity (%).

(3) The surface opposite to the surface provided with the reflectance antireflection layer is painted with black spray, and a spectral reflectance measuring device (a spectrophotometer U-3410 incorporating a large sample chamber integrating sphere attachment device 150-09090, (Manufactured by Hitachi, Ltd.), the reflectance of the polarizing diffraction element at wavelengths of 660 nm and 785 nm was measured from the antireflection layer side and evaluated. Specifically, the reflectance was measured at 660 nm and 785 nm, with the reflectance of the deposited aluminum film as a reference (100%).

(4) Glass transition temperature (Tg)
Using a DSC6200 manufactured by Seiko Instruments Inc., the temperature increase rate was measured at 20 ° C. per minute under a nitrogen stream. The Tg of the resin is plotted on the differential scanning calorific value maximum peak temperature (point A) and the temperature at −20 ° C. from the maximum peak temperature (point B) on the differential scanning calorimetry curve. And the intersection of the tangent starting from point A. The Tg of the ultraviolet curable acrylic resin was determined by measuring the glass transition temperature as a cured film using a forced resonance vibration type dynamic viscoelasticity measuring apparatus. Specifically, the loss tangent was measured at a rate of temperature increase of 3 ° C./min while applying vibration with a frequency of 10 Hz to the cured film. The temperature at which the loss tangent showed the maximum value was defined as the glass transition temperature (Tg).

(5) Total light transmittance was using Haze Suga Test Instruments Co. haze meter (HGM-2DP type) measuring the total light transmittance of the film.

(6) Refractive index The refractive index at 408 nm, 632.8 nm, and 830 nm is measured using a prism coupler (PC2010 type) manufactured by Metricon, and fitting is performed using the Cauchy's dispersion formula, and 25 in the wavelength range from 410 nm to 800 nm. The refractive index at ° C was determined.

[Synthesis Example 1] (Synthesis of Resin (A-1) (Cyclic Olefin Resin))
8-methyl-8-methoxycarbonyltetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene (DNM) 225 parts by mass and bicyclo [2.2.1] hept-2-ene (norbornene) 25 parts by mass are used as monomers, and 1-hexene (molecular weight adjustment) Agent) 27 parts by mass and toluene (solvent for ring-opening polymerization reaction) 750 parts by mass were charged into a nitrogen-substituted reaction vessel, and this solution was heated to 60 ° C. Subsequently, 0.62 parts by mass of a toluene solution of triethylaluminum (1.5 mol / liter) as a polymerization catalyst and tungsten hexachloride modified with tert-butanol and methanol (tert-butanol: methanol: Ring addition polymerization reaction was performed by adding 3.7 parts by mass of a toluene solution (concentration 0.05 mol / liter) of tungsten = 0.35 mol: 0.3 mol: 1 mol) and heating and stirring this solution at 80 ° C. for 3 hours. To obtain a ring-opening polymer solution. The polymerization conversion rate in this polymerization reaction was 97%.

A hydrogenated polymer (hereinafter referred to as “resin (A-1)”) was obtained by hydrogenating the ring-opened polymer thus obtained.
The Tg of the resin (A-1) thus obtained was 130 ° C.

[Synthesis Example 2] (Synthesis of Resin (A-2) (Cyclic Olefin Resin))
71 parts by mass of DNM, dicyclopentadiene (tricyclo [4.3.0.1 ^2,5 ] deca-3
, 7-diene) (DCP) 15 parts by mass and norbornene (NB) 1 part by mass as a monomer, together with 18 parts by mass of molecular weight regulator 1-hexene and 200 parts by mass of toluene, nitrogen-substituted reaction The container was charged and heated to 100 ° C.

To this, 0.005 parts by mass of triethylaluminum and 0.005 parts by mass of methanol-modified WCl ₆ (anhydrous methanol: PhPOCl ₂ : WCl ₆ = 103: 630: 427 mass ratio) were added and reacted for 1 minute, and then 10 parts by mass of DCP. And 5 parts by mass of NB are further added in 5 minutes, and further reacted for 45 minutes, whereby a structural unit derived from DNM / a structural unit derived from DCP / a structural unit derived from NB = 69.77 / 26.01. /4.23 (mass%) copolymer was obtained.

Subsequently, the obtained copolymer was subjected to a hydrogenation reaction to obtain a hydrogenated copolymer (hereinafter referred to as “resin (A-2)”).
The Tg of the resin (A-2) thus obtained was 131 ° C.

[Synthesis Example 3] (Synthesis of Resin (A-3) (Cyclic Olefin Resin))
Tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene 53 parts by mass and 8-ethylidenetetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] -3-dodecene (46 parts by mass) and tricyclo [4.3.0.1 ^2,5 ] -deca-3,7-diene (66 parts by mass) were used, and 1-hexene (molecular weight regulator) was used. ) Was added in an amount of 22 parts by mass, and a hydrogenated polymer (hereinafter referred to as “resin (A-3)” was synthesized in the same manner as in Synthesis Example 1 except that cyclohexane was used instead of toluene as a solvent for the ring-opening polymerization reaction. ").
The obtained resin (A-3) had a glass transition temperature (Tg) of 125 ° C.

[Synthesis Example 4] (Synthesis of polyimide)
As tetracarboxylic dianhydride, 2,2.4 g (0.1 mol) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride, and 19.8 g (0.1 mol) of 4,4′-diaminodiphenylmethane as a diamine compound Was dissolved in 800 g of N-methyl-2-pyrrolidone and reacted at 60 ° C. for 4 hours. The reaction solution was then poured into a large excess of methyl alcohol to precipitate the reaction product. Thereafter, it was washed with methyl alcohol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 390 g of polyamic acid having a logarithmic viscosity of 0.32 dl / g. 25 g of the obtained polyamic acid was dissolved in 475 g of N-methyl-2-pyrrolidone, 39.5 g of pyridine and 30.6 g of acetic anhydride were added, and dehydration and ring closure were performed at 110 ° C. for 4 hours. The pressure was reduced to obtain 19.5 g of polyimide having a logarithmic viscosity of 0.64 dl / g and an imidization rate of 92%.

[Synthesis Example 5] (Synthesis of polyamic acid ester)
0.1 mol (22.4 g) of 2,3,5-tricarboxycyclopentylacetic acid dianhydride and 0.1 mol (10.8 g) of p-phenylenediamine were dissolved in 300 g of N-methyl-2-pyrrolidone. The reaction was carried out at 6 ° C. for 6 hours. The reaction mixture was then poured into a large excess of methanol to precipitate the reaction product. Thereafter, it was washed with methanol and dried at 40 ° C. under reduced pressure for 15 hours to obtain 27.4 g of polyamic acid. To 16.6 g of the obtained polyamic acid, 350 g of N-methyl-2-pyrrolidone, 38.7 g of 1-bromo-6- (4-chalconyloxy) hexane and 13.8 g of potassium carbonate were added, and the mixture was heated at 120 ° C. for 4 hours. Reacted. The reaction mixture was then poured into water to precipitate the reaction product. The obtained precipitate was washed with water and dried under reduced pressure for 15 hours to obtain 35.4 g of a polyamic acid ester.

[Synthesis Example 6] (Synthesis of urethane acrylate)
In a reaction vessel equipped with a stirrer, 49.96 parts by mass of 2-phenoxyethyl acrylate, 0.01 parts by mass of 2,6-di-t-butyl-p-cresol, di-n-butyltin dilaurate 04 parts by mass and 17.74 parts by mass of tolylene diisocyanate were added and cooled to 5 to 15 ° C. When the temperature reached 10 ° C. or lower, 11.84 parts by mass of 2-hydroxyethyl acrylate was added dropwise with stirring, and the mixture was stirred for 1 hour while controlling the liquid temperature at 20 to 35 ° C. Thereafter, 20.40 parts by mass of bisphenol A alkylene oxide-added diol (DAO-400 manufactured by NOF Corporation) was charged, and the reaction was continued at 55 to 65 ° C. for 3 hours, so that the residual isocyanate became 0.1% by mass or less. The reaction was terminated and urethane acrylate was obtained.

[Preparation Example 1] (Preparation of UV curable acrylic resin)
Each component was charged into a reaction vessel equipped with a stirrer at the following blending ratio (parts by mass), and stirred at 50 ° C. for 1 hour to obtain a liquid composition. The specific blending ratio was 9.8 parts by mass of urethane acrylate obtained in Synthesis Example 6, 13.7 parts by mass of trimethylolpropane triacrylate, 29.4 parts by mass of tris (2-hydroxyethyl) isocyanuric acid acrylate, 32.3 parts by mass of polyoxyalkylene bisphenol A diacrylate, 4.9 parts by mass of a mixture of dipentaerythritol hexaacrylate / dipentaerythritol pentaacrylate, 7.8 parts by mass of N-vinyl-2-pyrrolidone, 1-hydroxycyclohexyl phenyl 1.5 parts by weight of ketone, 0.3 parts by weight of thiodiethylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 0.1 part by weight of diethylamine, polyoxyalkylene alkyl ether phosphorus 0.3 parts by mass of an acid ester, It was 100.1 parts by weight on the total. The viscosity of the ultraviolet curable acrylic material as the obtained liquid composition is 540 mPa · s at 25 ° C. using a rotational viscometer according to JIS K7117, and the Tg of the resin after UV curing is 120 ° C. The rate (Nu) was 1.534 at 660 nm and 1.530 at 785 nm.

[Preparation Example 1] (Preparation of alignment layer forming composition (B-1))
It has a structure in which the hydroxyl group of polyvinyl alcohol is substituted by 0.2 mol% of substituents —OCOPhO (CH ₂ ) ₄ OCOCH═CH ₂ and 11.8 mol% of substituents —OCOCH ₃ , having a saponification degree of 88 mol% and a polymerization degree of 300 5 parts by weight of the modified polyvinyl alcohol powder was mixed with 100 parts by weight of distilled water, and 35 parts by weight of methanol was added and dissolved. This solution was filtered using a filter having a pore diameter of 1 μm to prepare an alignment layer forming composition (B-1).

[Preparation Example 2] (Preparation of alignment layer forming composition (B-2))
The polyimide obtained in Synthesis Example 4 was dissolved in γ-butyrolactone, and 0.75 parts by weight of N-ethoxycarbonyl-3-aminopropyltriethoxysilane was dissolved with respect to 100 parts by weight of the polymer. A weight percent solution was obtained. This solution was filtered using a filter having a pore diameter of 1 μm to prepare an alignment layer forming composition (B-2).

[Preparation Example 3] (Preparation of alignment layer forming composition (B-3))
The polyamic acid ester obtained in Synthesis Example 5 was dissolved in γ-butyrolactone to dissolve 0.75 parts by weight of N-ethoxycarbonyl-3-aminopropyltriethoxysilane with respect to 100 parts by weight of the polymer, A solution having a concentration of 4% by weight was obtained. This solution was filtered using a filter having a pore diameter of 1 μm to prepare an alignment layer forming composition (B-3).

[Preparation Example 4] (Preparation of alignment layer forming composition (B-4))
Each component was charged into a reaction vessel equipped with a stirrer at the following blending ratio (parts by mass), and stirred and mixed at room temperature for 1 hour to obtain a liquid composition. The specific blending ratio was 90.1 parts by mass of dicyclopentanyloxyethyl acrylate, 7.2 parts by mass of isocyanurate triacrylate, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane- The amount of 1-one was 2.7 parts by mass, and the total amount was 100.0 parts by mass. The viscosity of the ultraviolet curable acrylic material as the obtained liquid composition is 24 mPa · s at 25 ° C. using a rotational viscometer according to JIS K7117, and the composition for forming an alignment layer is irradiated with ultraviolet rays. (B-4) was obtained.

[Preparation Example 5] (Preparation of optically isotropic material forming composition (D-1))
Each component was charged in a reaction vessel equipped with a stirrer at the following blending ratio (parts by mass), and stirred and mixed at 50 ° C. for 1 hour to obtain a composition (D-1). The specific blending ratio was 7.8 parts by mass of urethane acrylate obtained in Synthesis Example 6, 11.7 parts by mass of trimethylolpropane triacrylate, 31.4 parts by mass of tris (2-hydroxyethyl) isocyanuric acid acrylate ester, Polyoxyalkylene bisphenol A diacrylate 32.3 parts by mass, dipentaerythritol hexaacrylate / dipentaerythritol pentaacrylate mixture 4.9 parts by mass, N-vinyl-2-pyrrolidone 9.8 parts by mass, 1-hydroxycyclohexyl phenyl 1.5 parts by weight of ketone, 0.3 parts by weight of thiodiethylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 0.1 part by weight of diethylamine, polyoxyalkylene alkyl ether phosphorus 0.3 parts by mass of an acid ester, It was 100.1 parts by weight on the total. The viscosity of the obtained composition (D-1) is 540 mPa · s as measured at 25 ° C. using a rotational viscometer in accordance with JIS K7117. The Tg of the resin after UV curing is 120 ° C. and the refractive index (Nu). ) Was 1.534 at 660 nm and 1.530 at 785 nm.

[Preparation Example 6] (Preparation of optically isotropic material forming composition (D-2))
Each component was charged in a reaction vessel equipped with a stirrer at the following blending ratio (parts by mass), and stirred and mixed at room temperature for 1 hour to obtain a composition (D-2). Specifically, the blending ratio was 12.1 parts by mass of 1,6-hexanediol diacrylate, 5.0 parts by mass of 2-phenoxyethyl acrylate, 79.9 parts by mass of dicyclopentenyloxyethyl acrylate, 1-hydroxycyclohexyl phenyl ketone. The total amount was 3.0 parts by mass and 100.0 parts by mass in total. The viscosity of the obtained composition (D-2) is 21 mPa · s at 25 ° C. using a rotational viscometer according to JIS K7117, and the refractive index (Nu) of the resin after UV curing is 1 at 660 nm. 1.528 at 530 and 785 nm.

[Preparation Example 7] (Preparation of optically isotropic material forming composition (D-3))
Each component was charged in a reaction vessel equipped with a stirrer at the following blending ratio (parts by mass), and stirred and mixed at room temperature for 1 hour to obtain a composition (D-3). Specific blending ratios are as follows: 1,6-hexanediol diacrylate 51.2 parts by mass, 2-phenoxyethyl acrylate 26.2 parts by mass, isocyanurate triacrylate 19.7 parts by mass, 1-hydroxycyclohexyl phenyl ketone 2. The total amount was 90.0 parts by mass. The viscosity of the obtained composition (D-3) is 17 mPa · s at 25 ° C. using a rotational viscometer according to JIS K7117, and the refractive index (Nu) of the resin after UV curing is 1 at 660 nm. 1.520 at 520 and 785 nm.

[Production Example 1] (Production of substrate (a-1))
Resin (A-1) obtained in Synthesis Example 1 and pentaerythrityl tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] as an antioxidant were mixed with a twin-screw extruder (Toshiba). Extruded using Machine Co., Ltd .; TEM-48), the resin strand discharged from the strand die was cooled in a cooling water tank, then sent to a strand cutter, cut into rice granules, and granulated resin (transparent resin (A- 1)) was obtained. The addition amount of the antioxidant was 0.1 part by mass with respect to 100 parts by mass of the resin.

  Using this granulated resin, a resin film having a thickness of 130 μm was obtained using a single screw extruder (90 mmΦ) (hereinafter referred to as “base material (a-1)”). The residual solvent amount of the obtained film was 0.1%, the total light transmittance was 93%, and the glass transition temperature (Tg) was 130 ° C.

[Production Example 2] (Production of substrate (a-2))
In Production Example 1, a resin film having a thickness of 130 μm was obtained in the same manner as in Production Example 1 except that the resin (A-2) obtained in Synthesis Example 2 was used instead of the resin (A-1). (Hereinafter referred to as “base material (a-2)”). The film obtained had a residual solvent amount of 0.1%, a total light transmittance of 93%, and a glass transition temperature (Tg) of 131 ° C.

[Production Example 3] (Production of substrate (a-5))
In Production Example 1, a resin film having a thickness of 100 μm was obtained in the same manner as in Production Example 1 except that the resin (A-3) obtained in Synthesis Example 3 was used instead of the resin (A-1). (Hereinafter referred to as “base material (a-5)”). The film obtained had a residual solvent amount of 0.1%, a total light transmittance of 93%, and a glass transition temperature (Tg) of 124 ° C.

[Example 1]
On one side of the base material (a-1) obtained in Production Example 1, a rubbing treatment was performed using a rubbing machine manufactured by Iinuma Gauge Co., Ltd. with a roll rotation speed of 600 rpm, a film conveyance speed of 3 m / min, and a roll pushing amount of 0.3 mm. Was performed so that the rubbing direction was parallel to the film longitudinal direction, to obtain a substrate (a′-1). Next, 35 parts by mass of methyl ethyl ketone as a solvent was added to 100 parts by mass of RMM727, which is an ultraviolet curable liquid crystal material manufactured by Merck Co., Ltd., using an INVEX lab coater manufactured by Inoue Metal Industry Co., Ltd. using a 200 mesh small-diameter gravure roll. The substrate (a′-1) was rubbed under a condition of 50 ° C., applied to a surface imparted with molecular orientation ability, dried and oriented to form an optically anisotropic layer having a thickness of 4 μm. When the refractive index of the optically anisotropic layer on the substrate (a′-1) was measured, extraordinary refractive index Ne = 1.678, ordinary refractive index No = 1.542 in linearly polarized light with a wavelength of 660 nm, At 785 nm, the extraordinary refractive index Ne = 1.665 and the ordinary refractive index No = 1.535.

  Next, using the transfer roll prepared so that the pattern part in which the concave part and the convex part are continuously formed is transferred, the pattern part in which the concave part and the convex part are continuously formed is transferred to the coating surface. It was. The concave and convex portions on the surface of the transfer roll were prepared so that concave and convex grooves were formed along the circumferential direction of the roll.

Simultaneously with the transfer, the concave portion and the convex portion are continuously formed by irradiating ultraviolet rays with an energy amount of 500 mJ / cm ² from the surface side not having the pattern of the substrate (a′-1) using a high-pressure mercury lamp. The formed pattern part was formed and the base material (b-1) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm. Next, the optically isotropic material-forming composition (D-1) obtained in Preparation Example 5 was applied to the formed recesses using a 300-mesh small-diameter gravure roll using an INVEX laboratory coater manufactured by Inoue Metal Industry. Then, a filled portion made of an optically isotropic material is formed by irradiating and curing ultraviolet rays with an energy amount of 500 mJ / cm ² from the side having no pattern using a high-pressure mercury lamp, and a base material (c -1) was obtained. The thickness of the optically isotropic material was 4 μm from the bottom of the recess to the outermost layer.

Antireflection treatment was performed on both surfaces of the substrate (c-1) to obtain a polarizing diffraction element (1). The average value of ordinary light transmittance ao (λ) of the obtained polarizing diffraction element (1) measured at 2500 points is ao (λ ₁ ) = 98.8% for linearly polarized light having a wavelength of 660 nm and a wavelength of 785 nm. ao (λ ₂ ) = 99.5%, and the average value of the extraordinary light transmittance is ae (λ ₁ ) = 2.5% at a wavelength of 660 nm, and ae (λ ₂ ) = 7.7% at a wavelength of 785 nm. there were. The in-plane uniformity was 100%. The reflectance is 0.1% at 660 nm on the surface having the pattern and the filling portion (pattern side) and 0.1% at the wavelength of 785 nm, and is on the substrate (a′-1) side (substrate side). The surface was 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 10 mλ, in-plane uniformity was 100%, and a flat surface was formed.
The thickness of the polarizing diffraction element was 139 μm. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 2]
The base material (a-2) obtained in Production Example 2 was subjected to tenter transverse stretching at a stretching speed of 5.0 m / min and a stretching ratio of 3.5 times in a tank at a stretching machine furnace temperature of 155 ° C. A roll-shaped stretched film (base material (a′-2)) having a thickness of 37 μm was obtained. An optically anisotropic layer was formed in the same manner as in Example 1 except that the substrate (a′-2) was used. When the refractive index of the optically anisotropic layer on the substrate (a′-2) was measured, the linearly polarized light with a wavelength of 660 nm was extraordinary light refractive index Ne = 1.678, ordinary light refractive index No = 1.542, and 785 nm. The extraordinary light refractive index Ne = 1.663 and the ordinary light refractive index No = 1.534.

  Subsequently, the pattern part in which the recessed part and the convex part were continuously formed in the optically anisotropic layer surface was formed like Example 1, and the base material (b-2) was obtained. Next, in the same manner as in Example 1, a filling part was formed using the optically isotropic material-forming composition (D-1) to obtain a base material (c-2). The thickness of the optically isotropic material was 4 μm from the bottom of the recess to the outermost layer.

Antireflection treatment was performed on both surfaces of the substrate (c-2) to obtain a polarizing diffraction element (2). The average value of the transmittance of the polarizing diffraction element (2) obtained at 2500 points was ao (λ ₁ ) = 98.8%, ao (λ ₂ ) = 99.8%, and ae (λ ₁ ) = 2.4% and ae (λ ₂ ) = 7.2%. The in-plane uniformity was 100%. The reflectance is 0.2% at 660 nm and 0.1% at a wavelength of 785 nm on the surface having the pattern and the filling portion (pattern side), and is on the substrate (a′-2) side (substrate side). The surface was 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 9 mλ, in-plane uniformity was 100%, and a flat surface was formed. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 3]
An alignment layer-forming composition obtained in Preparation Example 1 using a 200-mesh small-diameter gravure roll on an 80-μm-thick triacetylcellulose film (base (a-3)) by INVEX Lab Coater manufactured by Inoue Metal Industry. (B-1) was applied. At the time of coating, filtration was performed with a 0.2 μm PTFE filter, and after coating, the solvent was evaporated and dried by passing through a dryer to form a coating layer. Drying was performed under stepwise conditions of 30 seconds at 100 ° C. and then 30 seconds at 120 ° C. Subsequently, the surface of the formed coating layer was rubbed with a rubbing machine manufactured by Iinuma Gauge Co., Ltd. with a roll rotation speed of 800 rpm, a film conveyance speed of 3 m / min, and a roll pushing amount of 0.3 mm. The base material (a′-3) to which the molecular orientation ability was imparted was obtained. Next, an optically anisotropic layer was formed in the same manner as in Example 1. When the refractive index of the optically anisotropic layer on the substrate (a′-3) was measured, the linearly polarized light wavelength was 660 nm, the extraordinary light refractive index Ne = 1.684, the ordinary light refractive index No = 1.543, and 785 nm. The extraordinary refractive index Ne = 1.661 and the ordinary optical refractive index No = 1.536.

  Subsequently, the pattern part by which the recessed part and the convex part were continuously formed in the optically anisotropic layer surface was formed like Example 1, and the base material (b-3) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm. Next, in the same manner as in Example 1, a filling portion was formed using the optically isotropic material-forming composition (D-1) to obtain a base material (c-3). The thickness of the optically isotropic material was 4 μm from the bottom of the recess to the outermost layer.

Antireflection treatment was performed on both surfaces of the substrate (c-3) to obtain a polarizing diffraction element (3). The average values of transmittance of the obtained polarizing diffraction element (3) measured at 2500 points were ao (λ ₁ ) = 98.5%, ao (λ ₂ ) = 99.6%, and ae (λ ₁ ) = 2.4% and ae (λ ₂ ) = 8.3%. The in-plane uniformity was 100%. The reflectance is 0.2% at 660 nm on the surface having the pattern and filling portion (pattern side), and 0.3% at the wavelength of 785 nm, and the surface on the substrate (a-3) side (substrate side). And 0.3% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 9 mλ, in-plane uniformity was 100%, and a flat surface was formed. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 4]
A coating layer is formed in the same manner as in Example 3 except that the polycarbonate film (base material (a-4)) having a thickness of 90 μm and the composition for forming an alignment layer (B-2) obtained in Preparation Example 2 are used. Then, a rubbing treatment was performed to obtain a base material (a′-4). Next, an optically anisotropic layer was formed in the same manner as in Example 1. When the refractive index of the optically anisotropic layer on the substrate (a′-4) was measured, the extraordinary light transmittance ← refractive index at a linearly polarizing wavelength of 660 nm? Abnormal light transmittance ← refractive index at Ne = 1.676, ordinary light refractive index No = 1.544, 785 nm? Ne = 1.663, ordinary light refractive index No = 1.537.

  Subsequently, the pattern part formed continuously similarly to Example 1 was formed, and the base material (b-4) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm. Next, in the same manner as in Example 1, a filling part was formed using the optically isotropic material-forming composition (D-1) to obtain a substrate (c-4). The thickness of the optically isotropic material was 4 μm from the bottom of the recess to the outermost layer.

Antireflection treatment was performed on both surfaces of the substrate (c-4) to obtain a polarizing diffraction element (4). The average values of transmittance of the obtained polarizing diffraction element (4) measured at 2500 points are ao (λ ₁ ) = 98.1%, ao (λ ₂ ) = 99.7%, and ae (λ ₁ ) = 2.7% and ae (λ ₂ ) = 8.2%. The in-plane uniformity was 99%. The reflectance is 0.3% at 660 nm on the surface having the pattern and the filling portion (pattern side), and 0.3% at the wavelength of 785 nm, and the surface on the substrate (a-4) side (substrate side). And 0.4% at 660 nm and 0.3% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 10 mλ, in-plane uniformity was 99%, and a flat surface was formed. The thickness of the polarizing diffraction element was 110 μm. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 5]
A coating layer was formed in the same manner as in Example 3 except that the base material (a-5) obtained in Production Example 3 and the composition for forming an alignment layer (B-3) obtained in Preparation Example 3 were used. . The coating layer was dried under stepwise conditions of 30 seconds at 100 ° C. and 30 seconds at 120 ° C. Subsequently, the surface of the formed coating layer was linearly polarized using a Hg-Xe lamp through a Pyrex (registered trademark) glass polarizing plate SPF-50C-32 (manufactured by Sigma Koki Co., Ltd.), mainly having a wavelength of 365 nm. Irradiation with ultraviolet rays of 0.5 J / cm ² gave a substrate (a′-5). The polarization plane direction of linearly polarized light was set to be parallel to the film longitudinal direction. Next, an optically anisotropic layer was formed in the same manner as in Example 1. When the refractive index of the optically anisotropic layer on the substrate (a′-5) was measured, the linearly polarized light wavelength 660 nm was extraordinary light refractive index Ne = 1.678, ordinary light refractive index No = 1.542, and 785 nm. The extraordinary refractive index Ne = 1.665 and the ordinary optical refractive index No = 1.535.

  Subsequently, the pattern part formed continuously similarly to Example 1 was formed, and the base material (b-5) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm.

Next, a composition for forming an optically isotropic material obtained in Preparation Example 5 was obtained by using a 300-mesh small-diameter gravure roll on the substrate (a-1) obtained in Production Example 1 using an INVEX laboratory coater manufactured by Inoue Metal Industry. The substrate (D-1) is applied, and the substrate is formed at an air cylinder pressure of 0.1 MPa and a feed rate of 1 / min using the unevenness forming side of the substrate (b-5) and VA-700 manufactured by Taisei Laminator Co., Ltd. By laminating the concave-convex forming side of (b-5) and curing it by irradiating ultraviolet rays with an energy amount of 500 mJ / cm ² from the base (a-1) side using a high-pressure mercury lamp. b-5) An optically isotropic filling part was formed in the concave part to obtain a substrate (c-5). The thickness of the ultraviolet curable acrylic material was 5 μm from the bottom of the recess to the base material (a-1).

Antireflection treatment was performed on both surfaces of the substrate (c-5) to obtain a polarizing diffraction element (5). The average values of transmittance of the obtained polarizing diffraction element (5) measured at 2500 points are ao (λ ₁ ) = 98.6%, ao (λ ₂ ) = 99.4%, and ae (λ ₁ ) = 2.5% and ae (λ ₂ ) = 7.9%. The in-plane uniformity was 100%. The reflectance is 0.2% at 660 nm on the substrate (a-1) side surface, 0.2% at the wavelength of 785 nm, 0.3% at 660 nm on the substrate (a-5) side surface, It was 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 5 mλ, in-plane uniformity was 100%, and a flat surface was formed. The thickness of the polarizing diffraction element was 279 μm. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 6]
A product obtained by diluting the base material (a-1) obtained in Production Example 1 and the polyether polyurethane material Hydran WLS-201 (manufactured by DIC Corporation) to 3% with methanol was manufactured by Inoue Metal Industry. The substrate was coated with an INVEX lab coater using a 200-mesh small-diameter gravure roll and heated and dried at 80 ° C. for 5 minutes to obtain a substrate having a polyurethane layer. Molecular orientation ability by rubbing with a rubbing machine manufactured by Iinuma Gauge Mfg. Co., Ltd. with a roll rotation speed of 600 rpm, a film conveyance speed of 3 m / min, and a roll indentation amount of 0.3 mm so that the rubbing direction is parallel to the film longitudinal direction. (A′-6) to which is given
Got. Next, an optically anisotropic layer was formed in the same manner as in Example 1. When the refractive index of the optically anisotropic layer on the substrate (a′-6) was measured, the extraordinary refractive index Ne = 1.676, the ordinary refractive index No = 1.542, and 785 nm at a linearly polarizing wavelength of 660 nm. The extraordinary light refractive index Ne = 1.663 and the ordinary light refractive index No = 1.534.

  Next, in the same manner as in Example 1, a filling part was formed using the optically isotropic material forming composition (D-1) to obtain a base material (c-6). The thickness of the optically isotropic material was 4 μm from the bottom of the recess to the outermost layer.

Antireflection treatment was performed on both surfaces of the substrate (c-6) to obtain a polarizing diffraction element (6). The average values of transmittance of the obtained polarizing diffraction element (1) measured at 2500 points were ao (λ ₁ ) = 98.4%, ao (λ ₂ ) = 99.3%, and ae (λ ₁ ) = 2.5% and ae (λ ₂ ) = 7.8%. The in-plane uniformity was 100%. The reflectance is 0.1% at 660 nm on the surface having the pattern and the filling portion (pattern side), and 0.1% at the wavelength of 785 nm, and the surface on the substrate (a-1) side (substrate side). And 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 12 mλ, in-plane uniformity was 98%, and a flat surface was formed. The thickness of the polarizing diffraction element was 140 μm. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Example 7]
An optically isotropic material-forming composition obtained in Preparation Example 5 using a 300-mesh small-diameter gravure roll on an INVEX laboratory coater manufactured by Inoue Metal Industry on one side of the substrate (a-1) obtained in Production Example 1 ( D-1) is applied, and then the concave and convex portions are continuously formed on the coated surface using a transfer roll prepared so that the pattern portion in which the concave and convex portions are continuously formed is transferred. The formed pattern portion was transferred. The concave and convex portions on the surface of the transfer roll were prepared so that concave and convex grooves were formed along the circumferential direction of the roll.

Simultaneously with the transfer, a concave portion and a convex portion are continuously formed by irradiating ultraviolet rays with an energy amount of 500 mJ / cm ² from the surface side not having the pattern of the base material (a-1) using a high-pressure mercury lamp. The formed pattern part was formed and the base material (b-7) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm.

  Next, on one side of the base material (a-1) obtained in Production Example 1, the roll rotation speed is 600 rpm, the film conveyance speed is 3 m / min, and the roll push-in amount is 0.3 mm with a rubbing machine manufactured by Iinuma Gauge Corporation. A rubbing treatment was performed so that the rubbing direction was parallel to the film longitudinal direction to obtain a base material (a "-7). Next, with a INMEX laboratory coater manufactured by Inoue Kinzoku Kogyo, RMM727, which is a UV curable liquid crystal material manufactured by Co., Ltd., applied 100 parts by mass with 30 parts by mass of acetone as a solvent, applied to a substrate (a "-7) under 50 ° C conditions, and dried. The film was oriented to a thickness of 4 μm. When the refractive index of the alignment layer on the substrate (a "-7) was measured, the extraordinary refractive index Ne = 1.678 at the linearly polarized wavelength 660 nm, the extraordinary refractive index No = 1.542, and the extraordinary refractive index at 785 nm. The rate Ne = 1.665 and the ordinary light refractive index No = 1.535.

Using the VA-700 manufactured by Taisei Laminator Co., Ltd., the concavo-convex forming side of the obtained base material (b-7) and the RMM727 application side of the base material (a "-7) were used. Lamination was carried out at / min, and ultraviolet rays were irradiated with an energy amount of 500 mJ / cm ² using a high-pressure mercury lamp and cured to obtain a substrate (c-7).

Antireflection treatment was performed on both surfaces of the substrate (c-7) to obtain a polarizing diffraction element (7). The average value of ordinary light transmittance of the obtained polarizing diffraction element (7) measured at 2500 points is ao (λ ₁ ) = 98.7% at a linearly polarizing wavelength of 660 nm and ao (λ ₂ ) = at 785 nm. The extraordinary light transmittance was ae (λ ₁ ) = 1.8% at a wavelength of 660 nm and ae (λ ₂ ) = 8.1% at a wavelength of 785 nm. The in-plane uniformity was 100%. The reflectance is 0.1% at 660 nm on the substrate (b-7) side surface, 0.1% at the wavelength of 785 nm, and 0.2% at 660 nm on the substrate (a ″ -7) side surface. The wavefront aberration was measured to find that λrms _ave = 4 mλ, the in-plane uniformity was 100%, and a flat surface was formed. The thickness of the diffractive element was 280 μm Table 1 shows the evaluation results of the obtained polarizing diffractive element.

[Example 8]
An alignment layer forming composition (B-4) obtained in Preparation Example 4 using a 300-mesh small-diameter gravure roll on an INVEX laboratory coater manufactured by Inoue Metal Industry on one side of the substrate (a-1) obtained in Production Example 1. Was applied, and immediately after coating, ultraviolet rays were irradiated from the coated surface side with an energy amount of 500 mJ / cm ² using a high-pressure mercury lamp to obtain a substrate (a "-1).

  Next, the substrate (a "-1) was longitudinally stretched at a stretching speed of 5.0 m / min and a stretching ratio of 1.5 times in a tank having a temperature in a stretching machine furnace of 145 ° C., and a roll having a thickness of 106 μm. A stretched film (base material (a "-2)) was obtained. Next, an optically anisotropic layer was formed in the same manner as in Example 1 on the coated surface side of the oriented layer forming composition (B-4) of the stretched film (base material (a ″ -2)). When the refractive index of the optically anisotropic layer on (a "-2) was measured, the linearly polarized light with a wavelength of 660 nm was extraordinary light refractive index Ne = 1.670, ordinary light refractive index No = 1.540, and 785 nm. The extraordinary refractive index Ne = 1.665 and the ordinary optical refractive index No = 1.535.

Subsequently, the pattern part in which the recessed part and the convex part were continuously formed was formed like Example 1, and the base material (b-8) was obtained. The width of the convex portion was 2.5 μm, the width of the concave portion was 2.5 μm, and the depth of the concave portion was 2.6 μm. Next, the optically isotropic material-forming composition (D-2) obtained in Preparation Example 6 was applied to the formed recesses using a 300-mesh small-diameter gravure roll using an INVEX laboratory coater manufactured by Inoue Metal Industry. Then, the coated surface and the base material (a-1) are laminated using a VA-700 manufactured by Taisei Laminator Co., Ltd. at an air cylinder pressure of 0.1 Mpa and a feed rate of 1 / min, and ultraviolet light is applied using a high-pressure mercury lamp. The substrate (c-8) was obtained by irradiating and curing with an energy amount of 500 mJ / cm ² .

Antireflection treatment was performed on both surfaces of the substrate (c-8) to obtain a polarizing diffraction element (8). The average value of ordinary light transmittance of the obtained polarizing diffraction element (8) measured at 2500 points was ao (λ ₁ ) = 99.1% at a linearly polarizing wavelength of 660 nm and ao (λ ₂ ) = at 785 nm. The extraordinary light transmittance was ae (λ ₁ ) = 2.9% at a wavelength of 660 nm, and ae (λ ₂ ) = 2.1% at a wavelength of 785 nm. The in-plane uniformity was 100%. The reflectance is 0.1% at 660 nm on the substrate (b-8) side surface, 0.1% at the wavelength of 785 nm, 0.2% at 660 nm on the substrate (a-1) side surface, It was 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 5 mλ, in-plane uniformity was 100%, and a flat surface was formed. The thickness of the polarizing diffraction element (8) was 270 μm. The evaluation results of the obtained polarizing diffraction element (8) are shown in Table 1.

[Example 9]
In Example 8, the longitudinal draw ratio was 1.2 times, and the ultraviolet curable acrylic material (D-2) was changed to the optically isotropic material-forming composition (D-3) obtained in Preparation Example 7. Obtained a base material (a "-3) and a polarizing diffraction element (9) in the same manner. When the refractive index of the RMM727 layer on the base material (a" -3) was measured, the linearly polarizing wavelength was 660 nm. The extraordinary refractive index Ne = 1.678, the ordinary optical refractive index No = 1.530, and the extraordinary refractive index Ne = 1.670 and the ordinary optical refractive index No = 1.523 at 785 nm. Average values of transmittance of the polarizing diffraction element (9) measured at 2500 points are ao (λ ₁ ) = 99.2%, ao (λ ₂ ) = 99.4%, and ae (λ ₁ ) = 2. 0.7% and ae (λ ₂ ) = 11.4%. The in-plane uniformity was 100%. The reflectance is 0.1% at 660 nm on the surface having the pattern and the filling portion (pattern side), and 0.1% at the wavelength of 785 nm, and the surface on the substrate (a-1) side (substrate side). And 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, it was found that λrms _ave = 5 mλ, in-plane uniformity was 100%, and a flat surface was formed. The thickness of the polarizing diffraction element was 270 μm. The evaluation results of the obtained polarizing diffraction element are shown in Table 1.

[Comparative Example 1]
A base material (a′-7) and a polarizing diffraction element (10) were obtained in the same manner except that the roll push-in amount of the rubbing machine was set to 0.4 mm in Example 1. When the refractive index of the RMM727 layer on the substrate (a′-7) was measured, the extraordinary refractive index Ne = 1.661 at the linearly polarized wavelength 660 nm, the extraordinary refractive index No = 1.538, and the extraordinary refractive index at 785 nm. The rate Ne = 1.667 and the ordinary light refractive index No = 1.531. Average values of transmittance of the polarizing diffraction element (7) measured at 2500 points are ao (λ ₁ ) = 97.4%, ao (λ ₂ ) = 99.1%, and ae (λ ₁ ) = 5. 0.1% and ae (λ ₂ ) = 12.4%. The in-plane uniformity was 80%. The reflectance is 0.1% at 660 nm on the surface having the pattern and the filling portion (pattern side), and 0.1% at the wavelength of 785 nm, and the surface on the substrate (a-1) side (substrate side). And 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring the wavefront aberration, λrms _ave = 14 mλ and in-plane uniformity was 90%. The thickness of the polarizing diffraction element (10) was 139 μm. The evaluation results of the obtained polarizing diffraction element (10) are shown in Table 1.

[Comparative Example 2]
The base material (a′-8) and the polarization were changed in the same manner as in Example 3 except that the roll pressing amount of the rubbing machine was 0.2 mm, and acetone was added instead of methyl ethyl ketone to RMM727 of the UV effect liquid crystal material. The diffractive element (11) was obtained. When the refractive index of the RMM727 layer on the substrate (a′-8) was measured, the extraordinary refractive index Ne = 1.669 at the linearly polarized wavelength 660 nm, the extraordinary refractive index No = 1.551, and the extraordinary refractive index at 785 nm. The rate Ne = 1.656 and the ordinary refractive index No = 1.544. Average values of transmittance of the polarizing diffraction element (11) measured at 2500 points are ao (λ ₁ ) = 96.5%, ao (λ ₂ ) = 97.9%, and ae (λ ₁ ) = 6. 0.7% and ae (λ ₂ ) = 15.7%. The in-plane uniformity was 48%. The reflectance is 0.1% at 660 nm on the surface having the pattern and the filling portion (pattern side), and 0.1% at the wavelength of 785 nm, and the surface on the substrate (a-1) side (substrate side). And 0.2% at 660 nm and 0.2% at a wavelength of 785 nm. As a result of measuring wavefront aberration, λrms _ave = 16 mλ and in-plane uniformity was 61%. The thickness of the polarizing diffraction element (11) was 141 μm. The evaluation results of the obtained polarizing diffraction element (11) are shown in Table 1.

  The polarizing diffraction element of the present invention can be usefully used in an optical system such as an optical pickup device capable of recording or reproducing information with respect to an optical recording medium such as a CD, DVD, or MO.

DESCRIPTION OF SYMBOLS 1 ... Base material 3 ... Layer 5 which has molecular orientation ability ... Optical anisotropic material 7 ... Convex part 9 ... Concave part 11 ... Optically isotropic material 13 ... Base Material 15 ... Pattern part 17 in which concave and convex parts made of optically anisotropic material are continuously formed 17 ... Base material 19 ... Application formed from a composition containing an optically isotropic material Surface 21: Optically isotropic material

Claims (14)

At least one surface of the transparent substrate has a diffraction grating layer formed of an optically isotropic material and an optically anisotropic material,
A polarizing diffraction element satisfying the following formulas (i) and (ii):
(I) 0.008 ≦ | Nu (λ ₁ ) −No (λ ₁ ) | ≦ 0.012
(Ii) 0.004 ≦ | Nu (λ ₂ ) −No (λ ₂ ) | ≦ 0.009
[In the formulas (i) and (ii),
λ ₁ : linearly polarized light having a wavelength of 660 nm,
λ ₂ : linearly polarized light having a wavelength of 785 nm,
Nu (λ ₁ ): refractive index of optically isotropic material at wavelength λ ₁
No (λ ₁ ): ordinary light refractive index of optically anisotropic material at wavelength λ ₁ ,
Nu (λ ₂ ): refractive index of optically isotropic material at wavelength λ ₂ ,
No (λ ₂ ): Represents the ordinary refractive index of the optically anisotropic material at the wavelength λ ₂ . (However, the refractive index and ordinary light refractive index are measured values at 25 ° C.)]   The diffraction grating layer has a pattern part in which a concave part and a convex part are continuously formed, and a filling part formed by filling the concave part, and the pattern in which the concave part and the convex part are continuously formed. 2. The polarizing diffraction element according to claim 1, wherein one of the portion and the filling portion is made of an optically isotropic material, and the other is made of an optically anisotropic material.   The polarizing diffraction element according to claim 2, wherein the pattern part in which the concave part and the convex part are continuously formed is made of an optically anisotropic material, and the filling part is made of an optically isotropic material.   The polarizing diffraction element according to claim 2, wherein the pattern part in which the concave part and the convex part are continuously formed is made of an optically isotropic material, and the filling part is made of an optically anisotropic material.   The polarizing diffraction element according to claim 2, wherein a pattern portion in which the concave portion and the convex portion are continuously formed is formed by transfer.   The polarizing diffraction element according to claim 1, wherein the transparent substrate is a resin.   The polarizing diffraction element according to claim 6, wherein the transparent resin is made of a cyclic olefin-based resin.   The polarizing diffraction element according to claim 1, wherein a layer having a molecular orientation ability is formed on a surface of the base material made of a transparent resin on which the diffraction grating layer is formed.   The polarizing diffractive element according to claim 1, wherein the optically anisotropic material includes an ultraviolet curable liquid crystal.   The polarizing diffractive element according to claim 1, wherein the optically isotropic material contains an ultraviolet curable (meth) acrylic resin.   The polarizing diffraction element according to claim 1, further comprising an antireflection layer on at least one surface. The polarizing diffraction element according to claim 11, further satisfying the following formulas (iii) to (vi).
(Iii) To (λ ₁ ) ≧ 95%
(Iv) To (λ ₂ ) ≧ 95%
(V) Te (λ ₁ ) ≦ 5%
(Vi) Te (λ ₂ ) ≦ 15%
[In the formulas (iii) to (vi)
λ ₁ : linearly polarized light having a wavelength of 660 nm,
λ ₂ : linearly polarized light having a wavelength of 785 nm,
To (λ ₁ ): normal light transmittance of vertically incident light having a polarization plane parallel to the normal refractive index direction of the optically anisotropic material at wavelength λ ₁ , To (λ ₂ ): optical difference at wavelength λ ₂ Normal light transmittance of perpendicular incident light having a plane of polarization parallel to the normal light refractive index direction of the anisotropic material, Te (λ ₁ ): with respect to the extraordinary light refractive index direction of the optically anisotropic material at the wavelength λ ₁ Extraordinary light transmittance of perpendicular incident light with polarization plane in parallel direction,
Te (λ ₂ ): represents the extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the extraordinary light refractive index direction of the optically anisotropic material at the wavelength λ ₂ . ] The polarizing diffraction element according to claim 11, wherein the following formulas (vii) to (x) are satisfied. (Vii) To (λ ₁ ) ≧ 95%
(Viii) To (λ ₂ ) ≧ 95%
(Ix) Te (λ ₁ ) ≦ 15%
(X) Te (λ ₂ ) ≦ 5%
[In the formulas (vii) to (x)
λ ₁ : linearly polarized light having a wavelength of 660 nm,
λ ₂ : linearly polarized light having a wavelength of 785 nm,
To (λ ₁ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₁ ,
To (λ ₂ ): ordinary light transmittance of perpendicular incident light having a polarization plane parallel to the direction of ordinary light refractive index of the optically anisotropic material at wavelength λ ₂ ,
Te (λ ₁ ): extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the direction of the extraordinary light refractive index of the optically anisotropic material at wavelength λ ₁ ,
Te (λ ₂ ): represents the extraordinary light transmittance of vertically incident light having a plane of polarization parallel to the extraordinary light refractive index direction of the optically anisotropic material at the wavelength λ ₂ . ]   The polarizing diffraction element according to claim 1, wherein the polarizing diffraction element is laminated with a wave plate and / or a diffraction grating.

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