JP2012108366A - Wire grid polarizing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a wire grid polarizing plate with stable quality which has a low defect in terms of optical performance and high quality, can be made into a lightweight and large area wire grid polarizing plate because of having excellent flexibility, has excellent processability and reliability, and can also be subjected to a secondary processing including deformation due to heating.SOLUTION: In the wire grid polarizing plate which includes a base material which is a polycarbonate resin film, a resin film which is formed on the base material and has a thickness in a range of 0.005 μm to 3 μm, and a metal wire formed on the resin film, the wire grid polarizing plate can be bent with a curvature radius of 10 cm or less.

Description

The present invention relates to a wire grid polarizing plate that can be preferably used for applications such as displays and sensors using polarized light.

  With the recent development of photolithography technology, it has become possible to form a fine structure pattern having a pitch at the wavelength level of light. Such a member or product having a pattern with a very small pitch is useful in a wide range of applications not only in the semiconductor field but also in the optical field.

  For example, a wire grid in which conductor wires made of metal or the like are arranged in a lattice pattern at a specific pitch has a pitch that is considerably smaller than the incident light (for example, half or less). It can be used as a polarizing plate to produce a single polarized light because it reflects almost all the light of the electric field vector component that oscillates parallel to the conductor line and almost transmits the light of the electric field vector component perpendicular to the electric conductor line. . Since the wire grid polarizer can reflect and reuse light that does not pass through, the wire grid polarizer is desirable from the viewpoint of effective use of light in applications such as a light source device of a display.

  In recent years, a wire grid polarizing plate of a glass substrate having a lattice-like uneven structure with a very narrow period has been developed. For example, U.S. Patent No. 6,057,051 deposits a transparent dielectric film on the surface of a transparent glass substrate, then uses holographic interference lithography to form a fine lattice structure in the photoresist, which is then An array of parallel grid conductive elements is formed on the substrate by transferring to a metal film by ion beam etching or reactive etching, and then the conductive elements are supported by etching the substrate using the grid conductive elements as a mask. It is disclosed that a rib having a periodic lattice-like uneven structure with a very narrow period is produced.

  However, a manufacturing method using a glass substrate and applying a semiconductor process has a drawback of poor productivity. Further, the wire grid polarizing plate of the glass substrate has a drawback in use such as being thick, heavy and easy to break.

  Patent Document 2 proposes a method of manufacturing a wire grid polarizer by forming a resin film with a photocurable resin PAK-01 (manufactured by Toyo Gosei) on a polycarbonate film substrate having a thickness of 100 μm by UV nanoimprint technology. Yes. However, according to the study by the present inventors, in the method disclosed in Patent Document 2, since the viscosity of the photocurable resin is high, the resin thickness of the photocurable resin tends to be uneven when the stamper is pressed, There were problems that a large number of defects were generated in the nanoimprint process, and that the transmittance and polarization performance were in-plane variations and lot-to-lot variations. In addition, the polycarbonate resin having high solvent solubility easily absorbs a liquid photo-curable resin such as PAK-01 after being applied to the film until it undergoes a curing reaction. A practical wire grid polarizing plate could not be manufactured due to the problems of weakening and being easily broken, and causing fine internal defects to cause whitening.

Special table 2003-502708 gazette JP 2008-145581 A

  The purpose of the present invention is good in terms of optical performance, low defects and high quality compared to conventional wire grid polarizers, and is thin, lightweight and has a large area because of its excellent flexibility. The object is to provide a wire grid polarizing plate that is excellent in workability and reliability, and that can be subjected to secondary processing including deformation by heating, with stable quality.

  As a result of investigations, the wire grid polarizing plate formed by forming a specific resin film on a specific polycarbonate resin film substrate and forming a metal wire on the resin film is a nanoimprint as described above. The problem in the process is improved, and because it is excellent in flexibility, it can be thin, lightweight and large in area, and can manufacture a wire grid polarizer with excellent workability and reliability with stable quality. And reached the present invention.

That is, the present invention is as follows.
(1) Wire grid polarization comprising: a base material made of a polycarbonate resin film; a resin film having a thickness of 0.005 μm to 3 μm formed on the base material; and a metal wire formed on the resin film. A wire grid polarizing plate which is a plate and can be bent with a radius of curvature of 10 cm or less.
(2) The wire grid polarizing plate as described in (1) above, wherein the polycarbonate resin film has a glass transition temperature of 140 ° C. or higher.
(3) The wire grid polarizer according to (1) or (2) above, wherein the polycarbonate resin film has a retardation value of 50 nm or less.

  The present invention is good both in terms of optical performance and low defect and high quality, and because it is excellent in flexibility, it can be manufactured in a thin, lightweight and large area, and it is also easy to process and improve reliability. An excellent wire grid polarizer can be provided with stable quality.

The wire grid polarizing plate of the present invention includes a base material made of a polycarbonate resin film, a resin film having a thickness of 0.005 μm to 3 μm formed on the base material, and a metal wire formed on the resin film. Thus, it is possible to bend with a radius of curvature of 10 cm or less.
Since bending is possible with a radius of curvature of 10 cm or less, it is excellent in flexibility, so that a product of stable quality can be manufactured with a large area at a low cost by a roll process. Further, when the wire grid polarizing plate is used for cutting into a desired shape, the product does not suffer from defects such as chipping. Furthermore, since the base material is a polycarbonate resin excellent in thermal processability, there is an advantage that secondary processing including deformation due to heating can be performed. Bending with a curvature radius of 10 cm or less can be achieved by using a base material made of a polycarbonate resin film and a photo-curing resin, which will be described later, in combination. The lower limit of the radius of curvature is about 0.3 mm due to the characteristics of the polycarbonate resin material.

  The polycarbonate resin film substrate constituting the wire grid polarizing plate is not particularly limited, and a film obtained by processing a conventionally known polycarbonate resin can be used. Among the film properties, the glass transition temperature depends on the production of the wire grid polarizing plate or the secondary. It is important in the process of processing, and the glass transition temperature is preferably 140 ° C. or higher in that the production process of the wire grid polarizing plate including heating can be stably controlled, and it is easy to obtain a film having excellent flatness and The glass transition temperature is preferably 170 ° C. or lower in that secondary processing can be easily performed. Moreover, the range of 145 degreeC to 165 degreeC is more preferable from the point of the availability of a film.

Further, when the retardation value is 50 nm or less among the characteristics of the film, not only the polarized light emitted from the metal wire side but also the polarized light emitted from the substrate side can be easily used for the wire grid polarizing plate of the present invention. Therefore, it is preferable. In this respect, the retardation value is more preferably 30 nm or less, and further preferably 10 nm or less. Note that the lower limit of the phase difference value is considered to be 0.1 nm in terms of the accuracy of the evaluation technique. Moreover, as long as the characteristic of a polycarbonate resin film is exhibited, it can use without a restriction | limiting in particular, such as an alloy with other resin, a blend, a compound.
There is no restriction | limiting in particular also in the form of a film base material, A roll-shaped or a sheet | seat film can be used. There is no particular limitation on the thickness of the base material, and those in the range of 4 μm to 2 mm can be used. However, the range of 8 μm to 500 μm is preferable in terms of ease of manufacture and handling, and the range of 15 μm to 200 μm in terms of continuous productivity. A range is particularly preferred.

In addition, a trace amount of residual components (especially chloride ions) remain in the film manufacturing method, but a polycarbonate resin film with as little residual amount of components as possible can prevent deterioration of optical properties due to coloring due to aging of the substrate. This is preferable because it is possible.
The film base is preferably subjected to a treatment for adjusting the adhesive force with the resin film. For example, in order to enhance the bonding force of the surface to be adhered to the resin film, a functional group treatment for enabling chemical bonding. And coating treatment, easy adhesion coating for physical bonding such as penetration, primer treatment, corona treatment, plasma treatment, high energy ray irradiation treatment, surface roughening treatment, porous treatment and the like.

  Polycarbonate resin has high solvent solubility, and it absorbs a large amount of photocurable resin and becomes brittle after the liquid photocurable resin that forms the resin film is applied to the film until it undergoes a curing reaction. Therefore, for the purpose of adjusting the amount of absorption of the photocurable resin and maintaining the flexibility, it is also preferable to perform a densification treatment such as a coating treatment that suppresses the penetration of the low molecular weight organic compound and an annealing treatment.

Depending on the purpose, the film base material should be combined with plasticizers, antioxidants, ultraviolet absorbers, dyes, pigments, flame retardants, gas barrier functions, adhesives, etc., or combined as a laminate It is also preferable. It is also preferable to form a dielectric thin film or a moth-eye structure on the surface for the purpose of controlling the light reflectance.
The resin film has a regular uneven structure on the surface whose height is in the range of 0.01 μm to 20 μm and the pitch extending in a specific direction is in the range of 0.01 μm to 20 μm, and the thickness is 0 A resin film made of a molded product of a photo-curing resin in the range of 0.01 μm to 3 μm is preferable. By taking such a structure, it becomes easy to form a metal wire on the uneven structure of the resin film.

As a characteristic of the wire grid polarizer, it is known that sufficient polarization performance can be obtained when the pitch of the metal wire is not more than a quarter of the wavelength of the target light, and that the polarization performance improves as the pitch becomes smaller. ing.
It is preferable that the uneven structure on the surface of the resin film and the pitch of the metal wires are 20 μm or less, so that polarization characteristics in the terahertz band can be expressed, and if the pitch is 150 nm or less, characteristics up to the visible range can be expressed. Furthermore, when the pitch is 120 nm or less, it is particularly preferable because it can have polarization characteristics up to a short wavelength light in the vicinity of 400 nm and to the ultraviolet region when it is about 10 nm. Since the extinction ratio in the wavelength region is also improved, it is more preferable.

  The height of the uneven structure on the surface of the resin film is sufficient for the purpose of forming a layer containing air around the metal wire in order to improve the optical performance, and to keep the distance between the metal wires constant and firm For the purpose of providing a rugged structure, the pitch is preferably in the range of 0.5 to 2.0 times, more preferably in the range of 1.0 to 2.0 times the pitch of the uneven structure.

  There is no restriction | limiting in the cross-sectional shape of the uneven structure on the surface of a resin film. These cross-sectional shapes may be trapezoidal, rectangular, square, prismatic, sinusoidal, such as semicircular. Here, the sinusoidal shape means that it has a curved portion formed by repetition of a concave portion and a convex portion. The curved portion only needs to be a curved curve. For example, a shape having a constriction in the convex portion is included in the sine wave shape. Further, in order to make it easier for the dielectric to cover the convex portions of the resin film and at least a part of the side surfaces thereof, it is preferable that the ends, vertices, and valleys of the shape have a curved shape with a gentle curvature.

As described above, the resin film is formed of a molded product of a photocurable resin, and a mixed layer with the polycarbonate resin of the base material is formed at the interface with the base material. The thickness of the resin film here means the total amount of the solid weight of the photocurable resin applied and cured on the base material including the photocurable resin that has penetrated into the base material. It is a value determined in terms of the thickness of the solid material of the curable resin.
The thinner the resin film, the more (a) the absorption of light in the resin film can be suppressed and the transmittance can be improved. (B) The amount of volatile residual components in the resin film can be reduced, and the bleed. Contamination due to such as can be prevented. (C) The curl generated by the curing shrinkage of the photocurable resin is reduced, and the flatness of the wire grid polarizer is improved. (D) The flexibility of the resin film is improved, and the occurrence of cracks when the wire grid polarizer is deformed can be suppressed. (E) Good effects such as improved followability to stress stress generated between layers of base material and metal wire due to changes in temperature and humidity, and increased stability in manufacturing process and reliability in use environment Was recognized.

  On the other hand, if the thickness of the resin film is reduced by nanoimprint technology to produce a transferred material, (f) the minute foreign matter mixed in the photocurable resin or the minute foreign matter floating around the production facility When mixed into the transfer surface, the frequency of occurrence of lens-like defects around the foreign matter increases. (G) It is difficult to uniformly coat the photocurable resin on the resin base material due to defects such as smears and liquid repellency, and the frequency of occurrence of transfer defects increases. (H) There is a problem that the photocurable resin is susceptible to oxygen inhibition, and unreacted components remain to increase the frequency of occurrence of transfer defects.

The wire grid polarizing plate of the present invention can be manufactured by adjusting the thickness of the resin film in the range of 0.005 μm to 3 μm by optimizing the composition of the photocurable resin and the transfer process.
In the wire grid polarizing plate of the present invention, the thickness of the resin film may be limited to 3 μm or less for the purpose of limiting the amount of the photocurable resin that permeates the polycarbonate substrate and maintaining the flexibility of the wire grid polarizing plate. Preferably, the thickness of the resin film is more preferably 2 μm or less for the purpose of improving durability against stress such as bending and cutting of the wire grid polarizer. In view of improving the flatness of the wire grid polarizer, the thickness of the resin film is particularly preferably 1 μm or less. On the other hand, when the resin film is extremely thin, most of the photocurable resin penetrates into the polycarbonate resin during the transfer process by nanoimprinting, and there is a problem of causing a transfer defect. 0.005 μm or more is preferable.

The wire grid polarizer of the present invention is preferably free from defects such as cracking due to bending with a radius of curvature of 10 cm or less and whitening due to fine internal defects for the purpose of manufacturing by a roll process, and facilitates secondary processing such as cutting. For the purpose of carrying out, it is more preferable not to cause problems due to bending with a radius of curvature of 5 cm or less, and for the purpose of easily carrying out fine processing such as bonding, it is particularly preferable that no problems with bending with a radius of curvature of 1 cm or less occur. . As a means for producing such a wire grid polarizing plate with flexibility maintained, the method of limiting the thickness of the resin film, or the amount of the photocurable resin penetrating into the polycarbonate resin base material by surface treatment of the base film Depending on the process conditions from the method of limiting, the method of adjusting the penetrability of the photocurable resin to the polycarbonate resin, and the curing reaction after the photocurable resin is applied on the film substrate, A method for adjusting the amount of permeation can be mentioned.
The wire grid polarizer manufactured in this way is resistant to stresses such as bending, stretching, and compression, can be easily cut, and does not cause defects such as whitening due to cracks or fine internal defects around the cutting line. It is also possible to cut into small pieces of arbitrary shapes and several millimeters square.

Moreover, it was confirmed that the wire grid polarizing plate of this invention has high reliability also with respect to the change of temperature and humidity because the thickness of a resin film can be made thin. Generally, when the non-surface area of the material increases, the reliability tends to decrease. However, in the case of the wire grid polarizer of the present invention, it is probably between the resin base material and the metal wire layer by reducing the thickness. As a result of improving the followability to the generated stress stress, it is estimated that the reliability is increased.
In order to reduce the thickness of the resin film and reduce the occurrence of transfer defects, the viscosity of the photo-curing resin used is low, the releasability from the stamper is good, and the permeability and adhesiveness to the polycarbonate resin substrate A good balance is required.

  The photocurable resin used in the present invention contains (A) one or more monomers containing 3 or more acrylic groups and / or methacrylic groups in one molecule in a range of 15 to 60% by weight. To do. (B) The component which becomes a solid by bonding by the photocuring reaction is 98% by weight or more. (C) It is preferable that it is a composition which satisfy | fills simultaneously that the viscosity in 25 degreeC is 12 mPa * s or less. Furthermore, (D) the silicon compound containing an acrylic group and / or a methacryl group is contained in the range of 0.1 to 10% by weight. (E) It is more preferable to add another monomer for the purpose of adjusting the viscosity and adjusting various physical properties of the cured product. (F) It is preferable that the compounding ratio of the photoinitiator to the photocurable resin composition is in the range of 0.1 to 5.0% by weight. (G) As for the photocurable resin composition, the thing from which the foreign material (particle) was removed by techniques, such as filtration, is preferable. In the case of filtration, it is preferable to use a filter having a minimum particle diameter of 1 μm or less that can be captured, and more preferably 0.5 μm or less in order to improve the yield when the resin film is thinned. For any minimum particle size, the filter capture efficiency is preferably 99.9% or more.

  In the photocurable resin composition, other conventional additives such as flow regulators, leveling agents, organic and inorganic dyes and pigments, extenders, plasticizers, and the like as long as they do not impair the original purpose. Lubricants, reinforcing agents, antioxidants, anti-yellowing agents, UV absorbers, bluing agents, anti-settling agents, antifoaming agents, antiwear agents, friction reducers, antistatic agents, antifogging agents, etc. Can be included.

  The resin film is preferably formed by optical nanoimprint technology in a roll process. For example, a photocurable resin composition is poured into a mold having a concavo-convex structure that is an inverted shape of the uneven structure on the surface of the resin film, and is photocured. Molded with. As a method for pouring the photocurable resin composition into the mold, after applying the photocurable resin composition to the polycarbonate resin base material in a thin film form, it is brought into contact with the mold, and between the uneven structure of the mold and the polycarbonate resin base material. And a method of filling the mold surface between the concavo-convex structure of the mold and the polycarbonate resin substrate by applying the photocurable resin composition to the surface of the mold in a thin film and then contacting the polycarbonate resin substrate. It is done.

  The method for applying the photocurable resin composition is not particularly limited. For example, a roll coater method, a (micro) gravure coater method, an air doctor coater method, a blade coater method, a knife coater method, a rod coater method, a curtain ( Flow) coater method, kiss coater method, bead coater method, cast coater method, rotary screen method, dip coating method, slot orifice coater method, barcode method, spray coating method, spin coating method, extrusion coater, fountain coater method, etc. It is done.

In any method, it is important not to mix air bubbles into the uneven structure of the mold and to reduce the thickness unevenness of the photocurable resin composition held between the mold and the polycarbonate resin substrate.
It is preferable that the temperature of the mold is constantly adjusted in the range of 25 ° C to 100 ° C. When the mold temperature is 25 ° C. or higher, the fluidity of the photocurable resin is improved, the effect of improving the adhesion between the resin film and the polycarbonate resin substrate, and the separation from the mold after the resin film is cured. This is preferable because it has an effect of improving moldability. Moreover, since the temperature of a mold is 100 degrees C or less, since the thermal deformation of a base material and the osmosis | permeation amount to the polycarbonate resin base material of a photocurable resin can be suppressed, it is preferable. The range of 30 ° C to 80 ° C is more preferable, the range of 35 ° C to 70 ° C is more preferable, and the range of 40 ° C to 65 ° C is particularly preferable.

The thickness of the resin film can be adjusted by the filling amount of the photocurable resin composition into the mold and the pressure for pressing the resin substrate and the mold.
The degree of cleanliness around the transfer equipment is preferably class 10000 or more, more preferably class 1000 or more, further preferably class 100 or more, and particularly preferably class 10 or more.

  In order to improve the adhesion between the resin film and the metal wire, the dielectric layer may be provided so as to cover the convex part on the surface of the resin film and at least a part of the side surface part before forming the metal wire. preferable. The dielectric constituting the dielectric layer is preferably a material having strong adhesion to the resin film and the metal constituting the metal wire. For example, silicon (Si) oxide, nitride, halide, carbide alone or its Composite, aluminum (Al), chromium (Cr), yttrium (Y), zirconia (Zr), tantalum (Ta), titanium (Ti), barium (Ba), indium (In), tin (Sn), zinc (Zn), magnesium (Mg), calcium (Ca), cerium (Ce), copper (Cu) and other metal oxides, nitrides, halides, carbides or their composites (in addition to dielectrics alone) Or a dielectric material in which a single element or a compound is mixed.

There is no restriction | limiting in particular as a metal which comprises a metal wire, For example, it is preferable to be comprised by aluminum (Al), silver, or those alloys. From the viewpoint of cost and durability, it is more preferably composed of Al or an alloy thereof.
There is no particular limitation on the method for forming the metal wire on the resin film, preferably on the dielectric layer formed so as to cover at least a part of the convex part of the resin film layer and the side surface part in advance. A physical vapor deposition method such as vacuum deposition, sputtering, or ion plating is preferred, and among them, a method in which a metal can be selectively laminated on the convex portion selectively or biased to one side of the convex portion is preferred. For example, a vacuum deposition method may be mentioned.

  The width of the metal wire is preferably in the range of 0.2 to 0.6 times the pitch of the uneven structure on the surface of the resin film from the viewpoint of optical characteristics and the structural strength of the wire grid. Further, the height of the metal wire is preferably in the range of 20 nm to 220 nm, considering the optical properties of the wire grid polarizer, the structural strength of the wire grid, and the adhesion between the metal wire and the uneven structure, and preferably 50 nm to 200 nm. A range is more preferred. Moreover, it is preferable on optical characteristics that the metal wire is provided so as to extend upward from the top of the convex portion on the surface of the resin film.

  The wire grid polarizing plate of this invention can also form an adhesive layer and an adhesive bond layer on the surface of a metal wire for the purpose of adhere | attaching on a desired article. It is also preferable to form a protective layer on the surface of the metal wire for the purpose of preventing dirt and providing cleaning properties. These pressure-sensitive adhesive layers and adhesive layers are not particularly limited, and conventionally known materials can be used. However, in order to suppress deterioration of the performance of the polarizing plate in a high-temperature and high-humidity environment, these layers are used. The acid value of is preferably 5.0 mgKOH / g or less. When these layers are formed on the surface of the metal wire, the region sandwiched between the metal wires is not filled with the material forming these layers in terms of expressing excellent optical performance, but air or these layers are not filled. It is preferable that the material is filled with a material having a refractive index smaller than that of the material to be formed, and the region sandwiched between the metal wires is filled with the material forming these layers in that the wire grid polarizing plate exhibits excellent durability. It is preferable that Depending on the purpose, plastic layer, antioxidant, UV absorber, dye, pigment, flame retardant, gas barrier function material, refractive index adjuster, etc. are blended into the protective layer on the surface of the metal wire, or laminate It is also possible to use a composite as It is also preferable to form a dielectric thin film or a moth-eye structure on the surface of the protective layer for the purpose of controlling the light reflectance.

  The wire grid polarizing plate of the present invention has a merit that since the base material is a polycarbonate resin excellent in heat processability, it is possible to perform secondary processing including deformation due to heating while maintaining the polarization separation function. . Specific examples of the secondary processing include press molding by heating, thermal stretching, and thermal lamination with an article to be adhered.

The present invention will be described based on examples.
The main measurement values in the examples were measured by the following methods.
(Measurement of viscosity)
An E type viscometer (model number RE550L manufactured by Toki Sangyo Co., Ltd.) was used for evaluation with a sample amount of 1.0 ml. All viscosity measurements were made at 25 ° C.

(Measurement of transmittance and degree of polarization)
About the wire grid polarizing plate of an Example and a comparative example, the polarization degree and the light transmittance were measured using the spectrophotometer (made by V-7100 JASCO). Here, the transmitted light intensity in a parallel Nicols state and a crossed Nicols state with respect to linearly polarized light was measured, and the degree of polarization and the light transmittance were calculated from the following equations. The measurement wavelength was 550 nm.
Polarization degree = [(Imax−Imin) / (Imax + Imin)] × 100%
Light transmittance = [(Imax + Imin) / 2]%
Here, Imax is the transmitted light intensity at the time of parallel Nicols, and Imin is the transmitted light intensity at the time of crossed Nicols.

(Defect observation)
Using a 10-fold magnifier, the presence or absence of defects in the resin thin film, the presence or absence of scratches, wrinkles, foreign matter, etc. were observed.
(Bending test)
Whether or not an abnormality such as cracking or whitening occurs while bending the wire grid polarizer along the outer periphery of a cylinder having a radius of 10, 5, 1, 0.5 cm and holding it for 10 minutes. evaluated.

[Example 1]
(Manufacture of wire grid polarizer)
Trimethylolpropane triacrylate is 25% by mass as a monomer that is a trifunctional or higher acrylate compound, N-vinyl-2-pyrrolidone is 5% by mass as a monomer that is an N-vinyl compound, and other monomers. As a photopolymerization initiator, 67% by mass of 1,9-nonanediol diacrylate, 2% by mass of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, and 1% by mass of silicon diacrylate were filtered. Then, the photocurable resin 1 was prepared. This viscosity was 11.0 mPa · s.

  After the above photo-curable resin 1 was continuously applied onto a roll-shaped polycarbonate resin film 1 (Teijin Kasei Co., Ltd. Panlite D-92) having a thickness of 92 μm, a width of 250 mm, and a length of 200 m, this state was maintained. After being transported for 5 seconds in a standard environment of 20 ° C. and 50% RH, the fine lattice pattern was continuously transferred by UV curing while being in contact with a roll stamper having the fine lattice pattern on the surface. When the cross section of this transfer film was observed with an electron microscope, the shape of the fine lattice pattern was an accurate inversion of the roll stamper, and it was confirmed that the line and space structure had a pitch of 100 nm and a height of 105 nm. . The thickness of the resin film was 0.4 μm.

A silicon nitride thin film was formed on the transfer surface side of the transfer film by a continuous film forming apparatus. Next, an aluminum wire was formed on the silicon nitride thin film to produce a wire grid polarizer 1.
In addition, the glass transition temperature of the polycarbonate resin film 1 used for manufacture was 145 degreeC, and the phase difference value was 11 nm or less.
Further, both the transfer and film forming processes are roll processes using a 6-inch core, but no defects such as cracking, chipping, and whitening were observed in the manufactured wire grid polarizer 1.

(Evaluation of wire grid polarizer)
About the wire grid polarizing plate 1, the polarization degree and the transmittance | permeability, the presence or absence of a fault, and the bending test were implemented in said way. The results are shown in Table 1.
As for the defects, no defects such as defects of the resin thin film were found over the entire surface of the product.
In the bending test, no abnormality was found in all the radii of curvature. Further, the wire grid polarizing plate was cut with scissors and the cut portion was observed with a 10-fold magnifier, but it was cut smoothly and no defects such as chipping occurred around the cutting line.

(Heat deformation of wire grid polarizer)
A square SUS metal mold having a lenticular lens-shaped relief structure with a maximum height of 100 μm and an average interval between peaks and valleys extending in a specific direction of 500 μm, and a wire grid polarizer 1 A method of applying pressure while heating in a state where the layers were stacked was used. Between the metal mold male (crest) and female (valley), the trough and the wire grid polarizing plate 1 so that the transmission axis direction of the wire grid polarizing plate 1 and the ridge line direction of the lenticular lens are orthogonal to each other. 1 After inserting the side not having the concavo-convex part facing each other, preheating at 130 ° C. for 5 minutes, pressing at 145 ° C. for 1 minute at a pressure of 50 kgf / cm 2, and then cooling to 20 ° C. A wire grid polarizer 1A having a light diffusion function was manufactured. When this was observed with a magnifying glass 10 times, abnormalities such as peeling of the surface layer of the wire grid due to press molding and cracks at the bent portion were not recognized at all, and the molding was smooth. Also, the degree of polarization and transmittance after molding were maintained.

[Comparative Example 1]
(Manufacture of wire grid polarizer)
Using a commercially available photocurable resin composition PAK-01 (manufactured by Toyo Gosei) instead of the photocurable resin 1, production of a wire grid polarizing plate was attempted in the same manner as in Example 1. The viscosity of this resin composition was 72.0 mPa · s. However, in the continuous transfer process, the coating thickness of the resin is not uniform, and bubbles are easily generated when the resin is brought into contact with the roll stamper, and the roll stamper is contaminated with the resin adhesion residue immediately after the transfer is started. For this reason, production by a continuous process was abandoned, and after PAK-01 was applied on a square polycarbonate resin film having a thickness of 92 μm, a width of 200 mm, and a length of 200 mm using a bar coater, the standard of 20 ° C. and 50% RH was used. After holding for 5 seconds in the environment, the fine lattice pattern was transferred by UV curing while being in contact with a flat stamper having a width of 100 mm and a length of 100 mm having the fine lattice pattern on the surface. Resin adhesion residue was generated. When the cross section of this transfer film was observed with an electron microscope, the shape of the fine lattice pattern was almost the reverse of the roll stamper, and a line and space structure with a pitch of 100 nm and a height of 105 nm was confirmed. In areas where resin residue was generated, a large number of regions having an average diameter of 200 to 2000 μm and no fine lattice pattern were present. The thickness of the resin film was slightly uneven and was in the range of 5 to 8 μm. A silicon nitride thin film was formed on the transfer surface side of the transfer film in the same manner as in Example 1 except that a batch type film forming apparatus was used for this transfer film. Next, an aluminum wire was formed on the silicon nitride thin film to produce a wire grid polarizer 2.

(Evaluation of wire grid polarizer)
In the same manner as in Example 1, the degree of polarization and transmittance, the presence or absence of defects, and a bending test were performed. The results are shown in Table 1 below.
As for the disadvantages, as described above, there are already many regions without a fine lattice pattern in the transfer process, and the film base material is partially whitened or cracked.
Regarding the bending test, defects such as cracking or whitening occurred for all the radii of curvature.

[Example 2]
(Manufacture of wire grid polarizer)
Production of a wire grid polarizing plate was attempted in the same manner as in Example 1 except that the polycarbonate resin film 3 (Iupizeta FPC-2136 manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used instead of the polycarbonate resin film 1. The polycarbonate resin film 3 had a glass transition temperature of 131 ° C. and a retardation value of 90 nm.
When the cross section of the film on which the fine lattice pattern was continuously transferred was observed with an electron microscope in the same manner as in Example 1, the shape of the fine lattice pattern was an exact inverted shape of the roll stamper, and the pitch was 100 nm. It was confirmed that the line and space structure had a height of 105 nm. The thickness of the resin film was 0.4 μm. However, when this transfer film was continuously formed on the transfer surface side of the transfer film by a continuous film forming apparatus, a wire grid polarizing plate was continuously produced because the film base material was largely thermally deformed. I couldn't.
Therefore, a silicon nitride thin film was formed on the transfer surface side of the transfer film in the same manner as in Example 1 except that a batch-type film forming apparatus was used for the transfer film. Next, an aluminum wire was formed on the silicon nitride thin film to produce a wire grid polarizer 3.

(Evaluation of wire grid polarizer)
About the wire grid polarizing plate 3, the polarization degree and the transmittance | permeability, the presence or absence of a fault, and the bending test were implemented in said way. The results are shown in Table 1 below. As for the defects, no defects such as defects of the resin thin film were found over the entire surface of the product.
In the bending test, no abnormality was found in all the radii of curvature. Further, the wire grid polarizing plate was cut with scissors and the cut portion was observed with a 10-fold magnifier, but it was cut smoothly and no defects such as chipping occurred around the cutting line.

  The present invention is good both in terms of optical performance and low defect and high quality, and because it is excellent in flexibility, it can be manufactured in a thin, lightweight and large area, and it is also easy to process and improve reliability. An excellent wire grid polarizer can be provided at low cost with stable quality. The wire grid polarizing plate of the present invention can also be subjected to secondary processing including deformation due to heating, and can be preferably used for applications such as a small display device that is required to be lightweight and thin, and a sensor that applies polarized light. .

Claims (3)

A wire grid polarizer comprising: a base material made of a polycarbonate resin film; a resin film having a thickness of 0.005 μm to 3 μm formed on the base material; and a metal wire formed on the resin film. A wire grid polarizer having a radius of curvature of 10 cm or less. The wire grid polarizing plate according to claim 1, wherein the polycarbonate resin film has a glass transition temperature of 140 ° C. or higher. The wire grid polarizing plate according to claim 1, wherein a retardation value of the polycarbonate resin film is 50 nm or less.