JP6720625B2 - Polarizer and method for manufacturing polarizer - Google Patents

Description

The present invention relates to a wire grid type polarizer.

Conventionally, in a liquid crystal display device, a liquid crystal material is sandwiched between glass plates on which transparent electrodes are arranged to form a liquid crystal cell, and linear polarizing plates are arranged on both surfaces of the liquid crystal cell to form a liquid crystal display panel. Further, in recent years, a device for improving the utilization efficiency of illumination light by the backlight by arranging a reflective linear polarizing plate on the incident surface (backlight side surface) of the liquid crystal display panel has been devised.

As such a polarizer, a structure (so-called sheet polarizer) produced by impregnating polyvinyl alcohol (PVA) with iodine or the like and then stretching it, a wire grid type polarizer, or the like is used. Patent Documents 1 and 2 propose a device for a wire grid type polarizer. Further, Patent Document 3 discloses a method of forming a wire grid type polarizer by disposing a metal material in each of the convex portions between the concave grooves and the concave portions of the concave grooves in the periodic structure by repeating the concave grooves. There is.

By the way, in recent years, liquid crystal display devices have been made thinner, and in particular, portable liquid crystal display devices are required to be further thinned. As a result, it is required to make the components of the liquid crystal display device thinner.

However, a polarizer using a sheet polarizer applied to such a liquid crystal display device has a drawback that it is inferior in heat resistance and it is difficult to further reduce the thickness. As a result, it is possible to use a wire grid type polarizer instead of the sheet polarizer. However, the conventional wire grid type polarizer has low production efficiency, and it is difficult to produce a large area product, which causes a problem that a large area product cannot be produced efficiently.

Although it is conceivable to fabricate a fine periodic structure relating to a wire grid type polarizer by stretching, in this case, it is difficult to fabricate with sufficient accuracy because the deformation rate is different between the central portion and the end portion. In addition, there is a problem that materials cannot be used efficiently.

JP, 2006-330521, A JP, 2012-27221, A U.S. Pat. No. 7,158,302

The present invention has been made in view of such a situation, and an object of the present invention is to enable a product with a large area to be efficiently produced for a wire grid type polarizer.

The present inventor has conducted extensive studies in order to solve the above problems, and creates an uneven shape having a periodic structure by repeating concave grooves, and forms a first metal linear portion on the top between the concave grooves. Then, at least the periodic structure of the concave grooves is continuously unwound from the winding body so as to form the polarizer, and is manufactured by a shaping process by a method of winding (so-called Roll to Roll method). This led to the completion of the present invention.

Specifically, the present invention provides the following.

(1) In a polarizer that limits the transmission of incident electromagnetic waves according to the plane of polarization,
On one surface of the substrate made of a transparent film material, a concave-convex surface is formed by repeating concave grooves at a pitch of the shortest wavelength or less of a wavelength band that limits transmission,
At least a top portion between the recessed grooves is provided with a first metal linear portion made of a metal material and extending along the recessed grooves,
The first metal linear portion,
The width of the portion in contact with the top between the recessed grooves is not more than the width of the top between the recessed grooves,
A polarizer having a teardrop-shaped cross-sectional shape in which the width gradually increases as the distance from the portion in contact with the top of the concave groove increases.

According to (1), it is possible to efficiently produce a large-area product by producing a concavo-convex surface by a shaping process by a method of continuously unwinding from the winding body and winding. Further, by providing the cross-sectional shape of the first metal linear portions formed by the etching treatment, in this case, the space between the first metal linear portions can be expanded by the etching treatment to secure the characteristics, which is sufficient. The incident light can be processed by such characteristics.

(2) In (1),
Furthermore, the polarizer in which a second metal linear portion made of a metal material and extending along the concave groove is provided at the bottom of the concave groove.

According to (2), it is possible to fabricate a polarizer including a metal linear portion having a two-layer structure including the first and second metal linear portions.

(3) In the polarizer according to any one of (1) and (2), the extending direction of the concave groove is the slow axis direction of the base material.

According to (3), the base material can be arranged so as to function in a direction that assists reflection and transmission by the metal linear portion, and thus the incident light can be processed more efficiently.

(4) In any one of (1), (2) and (3), a polarized light having an adhesive layer provided on the surface of the uneven surface for enhancing the adhesive force with the first metal linear portion. Child.

According to (4), the reliability can be improved by the adhesion layer, so that the uneven surface can be produced more reliably and continuously by unwinding from the winding body, and the uneven surface is formed by the shaping process by the winding method. Area products can be produced efficiently.

(5) A base material made of a long transparent film material is drawn out from a roll and subjected to a shaping process using a roll plate to form an uneven surface by repeating concave grooves at a pitch equal to or shorter than the shortest wavelength of a wavelength band that limits transmission. An uneven shape producing step of producing the base material;
A metal linear part forming step of depositing a metal material on the surface of the uneven surface to form a first metal linear part made of the metal material provided at the top between the concave grooves,
The method for manufacturing a polarizer, further comprising an etching step of etching the metal material deposited on the surface of the uneven surface.

According to (5), at least an imprinting process is performed to produce an uneven surface, and this imprinting process is continuously unwound from the winding body and is performed by a winding method to form a polarizer. By being able to manufacture, a large-area product can be efficiently produced. Further, the characteristic can be secured by expanding the width of the gap between the first metal linear portions narrowed by depositing the metallic material by the etching treatment, and thus the incident light can be treated with sufficient characteristics.

(6) In (5),
The uneven shape manufacturing step,
The method for manufacturing a polarizer, wherein the concavo-convex shaped surface is formed so that the extending direction of the concave groove is the slow axis direction of the base material.

According to (6), the base material can be arranged so as to function in a direction that assists reflection and transmission by the metal linear portion, and thus the incident light can be processed more efficiently.

According to the present invention, it is possible to efficiently produce a large-area product for the wire grid type polarizer.

It is a figure which shows the image display apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the polarizer applied to the image display apparatus of FIG. FIG. 3 is a diagram for explaining a pitch of the polarizer of FIG. 2. FIG. 4 is a chart provided for explaining the continuation of FIG. 3. 3 is a flowchart showing manufacturing steps of the polarizer of FIG. 2. FIG. 6 is a diagram provided for explaining FIG. 5. It is a figure with which explanation of an etching process is offered. It is a figure with which it uses for explanation of sectional shape of a metal linear part. It is a figure with which explanation of a lamination process is offered. It is a figure with which explanation of a roll plate is offered. It is a figure which shows the polarizer which concerns on other embodiment.

[First Embodiment]
[Overall configuration of image display device]
FIG. 1 is a sectional view showing an image display device using a polarizer manufactured according to the present invention. The image display device 1 is a liquid crystal display device, in which a backlight 3 is arranged on the back surface of the liquid crystal display panel 2, and a polarizer 4 is arranged on the backlight 3 side of the liquid crystal display panel 2. Here, as the backlight 3, surface light source devices of various configurations such as an edge light type and a direct type can be widely applied. The liquid crystal display panel 2 is configured by sandwiching a liquid crystal cell 5 between linear polarizing plates 6 and 7 arranged in a crossed Nicols arrangement or a parallel Nicols arrangement. The liquid crystal cell 5 sandwiches a liquid crystal material between glass substrates having transparent electrodes formed thereon. It is formed. As a result, the image display device 1 modulates the intensity of the transmitted light on a pixel-by-pixel basis by the voltage applied to the transparent electrode provided in the liquid crystal cell 5 and outputs the modulated image to display a desired image. The linear polarization plates 6 and 7 are so-called sheet-polarizer type polarizers.

The polarizer 4 is a wire grid type polarizer, and is a so-called reflection type polarizer that selectively and efficiently reflects incident light from a polarization plane orthogonal to the transmission axis direction. The polarizer 4 is arranged such that the transmission axis direction of the linearly polarizing plate 7 arranged on the incident surface side (backlight 3 side) of the liquid crystal cell 5 is aligned with the transmission axis direction, and the liquid crystal display panel 2 and the backlight 3 are arranged. And the image display device 1 improves the utilization efficiency of the illumination light from the backlight 3. In this embodiment, the polarizer 4 is integrated with the linear polarizing plate 7 in advance and then provided to the manufacturing process of the liquid crystal display panel 2, whereby the image display device 1 is assembled by the polarizer 4. Can be simplified. It should be noted that instead of being integrated with the linear polarizing plate 7 in this way, it may be arranged as a separate body.

This integration is performed by bonding the polarizer 4 and the linear polarizing plate 7 with an adhesive made of an ultraviolet curable resin or the like, but a layer having an optical function as a polarizer (first and second layers to be described later). Only the shape-imparting resin layer 16 including the two metal linear portions 12 and 13) may be transferred by a transfer method to be executed. Note that the transfer method is, for example, when a desired layer is formed on a base material, this layer is not directly formed on the base material but is once peeled off on a releasable support. After forming layers to form a transfer body, the layer formed on the support is finally placed on the base material (transferred base material) on which the layer is to be laminated, depending on the process, demand, etc. It is a method of forming a desired layer on the base material by adhering and laminating, and then peeling and removing the support.

[Polarizer]
FIG. 2 is a diagram showing the configuration of the polarizer 4. The polarizer 4 is a polarizer that restricts the transmission of incident light, which is an incident electromagnetic wave, according to the plane of polarization of the incident light. In the polarizer 4, concave grooves 11 are repeatedly provided at a constant pitch P on the surface of a transparent member 10 which is transparent in a wavelength band for controlling transmission, and the concave and convex are repeatedly formed in a direction orthogonal to the extending direction of the concave grooves 11. A periodic structure with a shape is provided.

In the polarizer 4, a metallic material is arranged on top of the convex portions between the concave grooves 11 according to this periodic structure, and thereby a first metallic linear portion made of a metallic material extending along the concave grooves is provided. .. Further, the same metal material is arranged on the bottom surface of the concave portion formed by the concave groove 11, and the second metal linear portion 13 made of the metal material extending along the concave groove is provided. The polarizer 4 has a repeating pitch P of the first and second metal linear portions 12 and 13 (which is a repeating pitch of the recessed grooves 11) in a visible wavelength band in which transmission is controlled by the polarizer 4. It is manufactured with a pitch P (P≦<<λmin) which is equal to or shorter than the shortest wavelength λmin in the region. As a result, the polarizer 4 has a two-layer structure including the first metal linear portions 12 provided on the tops of the concave grooves 11 and the second metal linear portions 13 provided on the bottom surface of the concave grooves 11. The metal linear portions 12 and 13 are formed and configured to function as a polarizer. In this embodiment, the visible light range is a wavelength range of 780 nm or less and 380 nm or more.

Here, the concave and convex shape formed by repeating the concave groove 11 is such that the flat groove is sandwiched between the concave grooves 11, and the concave groove 11 having a rectangular cross section is produced, whereby the polarizer 4 has the top of the convex portion and the bottom of the concave portion. The first and second metal linear portions 12 and 13 are formed by flat surfaces, and a metal material is arranged on the top and bottom portions with a constant thickness T1 and T2, respectively. As a result, the first and second metal linear portions 12 and 13 are formed with flat surfaces on the top side of the convex portion and the bottom side of the concave groove corresponding to the top shape of the convex portion and the bottom portion of the concave portion, respectively. .. However, the top portion of the convex portion and/or the bottom portion of the concave portion may be formed, for example, in an arc shape in cross section, and various shapes can be widely applied. As a result, the first and second metal wires can be formed. Various shapes corresponding to the top shape of the convex portion and the bottom surface shape of the concave portion can be applied to the shape portions 12 and 13. Correspondingly, various shapes can be applied to the metal linear portions 12 and 13 even if they are on the side opposite to the top side of the convex portion and on the side opposite to the bottom side of the concave portion.

However, simply, the concave groove 11 is repeated at the pitch P which is the shortest wavelength λmin or less of the wavelength band for controlling the transmission, and the polarizer 4 is formed by the two-layer structure of the first and second metal linear portions 12 and 13. If it is formed, it becomes impossible to secure sufficient transmittance in a wide wavelength range of the visible light range, which is a wavelength range in which the polarizer 4 controls transmission. More specifically, the wavelength dispersion of the transmittance increases, and as a result, the transmittance decreases on the short wavelength side.

Here, FIG. 3 shows the wavelength dispersion characteristic of the transmittance Tp (transmission axis direction) depending on the change of the pitch P in the polarizer having the two-layer structure including the first and second metal linear portions 12 and 13. It is a characteristic curve figure. The characteristic curve diagram of FIG. 3 and various characteristics described below are calculated by using the optical calculation simulation software “DiffractMOD” manufactured by Rsoftsy.

In FIG. 3, reference numeral L1 represents the case where the pitch P is 100 nm, the gap width S between the first metal linear portions 12 (see FIG. 6E) is 40 nm, and the gap width S with respect to the pitch P is S. Is 0.4, the depth D of the concave groove 11 is 100 nm, and the thicknesses T1 and T2 of the metal linear portions 12 and 13 are 40 nm. Here, the depth D of the concave groove 11 is the depth of the entire groove including the adhesive layer and the like when the adhesive layer and the like to be described later are provided, and the first and second metal linear portions 12 and 13 are provided. Is the distance between the bottoms of the. In addition, in this embodiment, the thicknesses T1 and T2 of the metal linear portions 12 and 13 are average values of the measurement results obtained by measuring the thickest portion in the groove width direction at a plurality of positions in the extension direction of the metal linear portions. is there. Further, in this embodiment, even if there is a gap width S between the first metal linear portions 12 or the like, it is an average value of measured values at a plurality of similar positions.

On the other hand, reference numeral L2 indicates that the pitch P is 64 nm, the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P is 0.3, and the depth D of the concave groove 11 is 75 nm. Other than these, the configuration is the same as that of the symbol L1. On the other hand, reference numeral L3 indicates that the pitch P is 64 nm, and the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P is 0.4. It has the same configuration as L2. The symbol L4 is the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P is 0.5, and the symbol L5 is the ratio S/P is 0.6. Other than these, the configuration is the same as that of the symbol L2. In these configurations, the ultraviolet curable resin (refractive index n=1.51, extinction coefficient k=0.00: at 550 nm) is applied to the transparent member 10, and the metal related to the metal linear portions 12 and 13 is applied. Aluminum (refractive index n=0.75, extinction coefficient k=5.44: at 550 nm) was used as the material.

According to the measurement results of FIG. 3, when the pitch P is set to 100 nm, which is less than or equal to the shortest wavelength in the visible light range, a sharp decrease in the transmittance is observed on the short wavelength side, which results in a wavelength dispersion characteristic of the transmittance. Degradation is observed. However, when the pitch P is 64 nm, such deterioration of the wavelength dispersion characteristic relating to the transmittance is eliminated, and although not shown in FIG. 3, deterioration of the wavelength dispersion characteristic is also eliminated in the reflectance, and further, Deterioration of the wavelength dispersion characteristic is eliminated even in the transmittance of the polarization component whose polarization plane is orthogonal to the polarization component shown in FIG. In the polarizer in which the metal linear portions 12 and 13 are formed by the two-layer structure by these, by simply repeating the concave groove 11 at the pitch P which is equal to or shorter than the shortest wavelength λmin of the wavelength band for controlling transmission, It can be seen that the transmittance cannot be sufficiently secured in a wide wavelength range of. Further, it can be seen that when the pitch P is set to 64 nm, such characteristic deterioration on the short wavelength side is eliminated.

FIG. 4 is a table showing the measurement results when the pitch P and the like are further changed in consideration of the measurement results of FIG. In each of the polarizers of FIG. 4, a transparent member and a metal linear portion were made of the same material and structure as those described above with reference to FIG. Here, the polarizer No. 1 to 5 and polarizer No. 6 and 7 are the cases where the pitch P was 40 nm and 60 nm, respectively, and the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P was 0.4. The concave groove 11 has a depth D of 40 nm (No. 1), 60 nm (No. 2, No. 4 to No. 7), 80 nm (No. 3), and the thickness T (= of the metal linear portions 12 and 13). T1 and T2) were set to 16 nm (No. 1 to 3, No. 6), 32 nm (No. 4 and 7) and 48 nm (No. 5).

When the measurement result of FIG. 4 is judged with reference to the measurement result of FIG. 3, it can be understood that the deterioration of the wavelength dispersion characteristic relating to the transmittance can be sufficiently solved practically when the pitch P is 64 nm or less. Further, assuming this pitch P, the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P is 0.4, and the transmittance Tp at wavelengths 400 nm, 600 nm, and 800 nm is 80% or more. As a result, it is confirmed that even if the transmittance in the transmission axis direction is sufficient, practically sufficient characteristics can be secured, and by these, sufficient transmittance can be secured in a wide wavelength band of the visible light region. It In FIG. 4, the measurement wavelength on the short wavelength side is 400 nm, but even at 380 nm, which is the shortest wavelength in the visible light range, a transmittance almost equal to the measurement result at the wavelength of 400 nm in FIG. 4 was measured.

Here, in FIG. 4, although the measurement result of the polarizer in which the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P is 0.4 is shown, In the ratio S/P of the void width S between the metal linear portions 12 of, it is produced by 0.3 or more and 0.5 or less, preferably 0.35 or more and 0.45 or less, Similarly, it is possible to secure sufficient transmittance in a wide wavelength band of the visible light range. Similarly, the pitch P is set to 80 nm or less, preferably 70 nm or less, and more preferably 50 nm or less, so that the deterioration of the wavelength dispersion characteristic relating to the transmittance can be sufficiently solved practically.

Further, in this measurement result, when the thickness T of the metal linear portions 12 and 13 is 16 nm, the thickness T of 32 nm is obtained when the transmittance Ts in the direction orthogonal to the transmission axis direction is 10% or more. In the case of 48 nm (Nos. 4, 5, and 7), the transmittance Ts sharply decreases. As a result, it is preferable that the metal linear portions 12 and 13 be manufactured to have a thickness of 32 nm or more. The maximum value of the thickness of the metal linear portions 12 and 13 is the depth D of the concave groove 11. By producing the thickness T with a thickness of 32 nm or more in this way, the transmittance Ts of incident light whose polarization direction is the extension direction of the metal linear portions 12 and 13 can be 1.3% or less.

In addition, in this measurement result, the polarizer No. In Nos. 1 to 3, when the pitch P, the ratio S/P, and the thickness T of the metal linear portions 12 and 13 are the same, the change in the depth D of the concave groove 11 causes a change in the direction orthogonal to the transmission axis direction. The transmittance Ts greatly changes. As a result, although it is desirable to form the concave groove 11 with a depth D of 60 nm or more and 120 nm, a sufficient transmittance T _P in the repeating direction of the metal linear portions 12 and 13 is ensured, and further, in the visible light region. From the viewpoint of ensuring such characteristics, the depth D is preferably 70 nm or more and 100 nm or less, and more preferably 75 nm or more and 85 nm or less.

As a result, in this embodiment, the polarizer 4 is manufactured with a pitch P of 80 nm or less on the premise of a two-layer structure including the first and second metal linear portions 12 and 13. Further, the polarizer 4 is manufactured by setting the ratio S/P of the gap width S between the first metal linear portions 12 to the pitch P to 0.3 or more and 0.5 or less.

In the polarizer 4, a shaping resin layer 16 of the transparent member 10 is provided on a base material 15 made of a transparent film material, and a shaping process of the shaping resin layer 16 forms a periodic structure of the concave grooves 11. .. Further, a metal layer is formed on the surface on which the periodic structure is formed by vapor deposition, sputtering, electroplating, electroless plating, or the like to form the metal linear portions 12 and 13. The base material 15 of the polarizer 4 is adhered to the linear polarizing plate 7 with an adhesive layer such as an ultraviolet curable resin to be held integrally. In addition, in the opposite direction, the linear linear polarization plate 7 may be attached and held from the metal linear portion 12 side. In addition, the base material 15 side or the side opposite to the base material side may be the linear polarizing plate 7 side and may be arranged separately from the linear polarizing plate 7.

Here, as the base material 15, a transparent film material made of a resin material produced by stretching is applied, and due to the expression of optical anisotropy due to this stretching, the refractive index in the stretching direction is higher than that in the direction orthogonal to the stretching direction. A resin material that increases as a result (that is, a resin material whose stretching direction is the slow axis direction) is applied. Note that such a resin material is a resin material exhibiting positive birefringence and is, for example, a PET (polyethylene terephthalate) resin or the like. Moreover, a COP (cyclo olefin polymer) film, a TAC (triacetyl cellulose) film, a polyimide film, and PEN (polyethylene naphthalate) are mentioned. However, when the Wet process is applied in the etching process in the manufacturing process, the TAC film is not preferable because the volume change due to water absorption is large. Alternatively, only the shape-imparting resin layer 16 and the first and second metal linear portions 12 and 13 may be arranged on the linear polarizing plate 7 by a transfer method. In this case, the base material 15 includes a PET film, a polyolefin film, Various base materials, such as a film with a release layer, can be applied to the extent that unintended peeling does not occur in the manufacturing process.

The polarizer 4 is formed such that the extending directions of the first and second metal linear portions 12 and 13 are parallel to the slow axis direction of the base material 15. If the setting is made in this way, in the base material 15, the metal linear portions 12 and 13 have the largest refractive index in the in-plane direction with respect to the polarization component reflected by the metal linear portions 12 and 13. , 13 is arranged so that the polarized component reflected by the light sources 13 and 13 is reflected most efficiently. Further, as a result, with respect to the polarized light component transmitted through the metal linear portions 12 and 13, the base material 15 is arranged in the direction in which the interface reflection is minimized, and the polarized light transmitted through the metal linear portions 12 and 13 is obtained. The base material 15 is arranged in the direction in which the components are most efficiently transmitted.

With these, the polarizer 4 is arranged so as to assist the reflection and transmission by the metal linear portions 12 and 13 by the reflection and transmission of the base material 15, respectively. The reflected light of the polarizer 4 returns to the backlight 3, the polarization plane is changed due to internal reflection in the backlight, and the light is incident on the polarizer 4 again, thereby improving the utilization efficiency of the backlight light. be able to.

Although various curable resins that can be subjected to a mold treatment can be applied to the shape-imparting resin layer 16, an ultraviolet-curable resin is applied in this embodiment. The base material 15 may be heated and softened to be pressed by a molding die to perform a shaping process. In this case, the shaping resin layer 16 is composed of the base material 15. ..

An adhesive layer may be provided on the surface of the shape-imparting resin layer 16 in order to improve the adhesiveness with the metal linear portions 12 and 13. The adhesion layer is not particularly limited, but Si or a compound thereof can be mainly applied, and SiO _x (x is 1 or more and 2 or less), SiC, or the like is preferable. In addition, these can be produced by surface treatment such as sputtering. The thickness of the adhesive layer is preferably 2 nm or more and 30 nm or less, more preferably 2 nm or more and 10 nm or less.

As the metal material for the metal linear portions 12 and 13, for example, metals, alloys, metal compounds, etc. relating to various conductors can be widely applied, but any of these metals made of aluminum, nickel, chromium or silver, or any of these. It is desirable to apply alloys of these metals and compounds of these metals. From the viewpoint of efficiently reflecting electromagnetic waves that limit transmission, it is desirable to use metals, alloys, and compounds with high reflectance such as aluminum, nickel, and silver, and aluminum is particularly preferable for visible light. On the contrary, from the viewpoint of suppressing reflection of electromagnetic waves that limit transmission, it is desirable to apply a metal, alloy or compound having a low reflectance such as chromium.

The metal linear parts 12 and 13 may be manufactured by a plurality of layer structures. By producing with such a layered structure, for example, the characteristics of the incident light incident from above and below the metal linear portions 12 and 13 are made different, and the hues of both surfaces of the metal linear portions 12 and 13 are made different. be able to.

The metal linear portions 12 and 13 can be manufactured by vapor deposition, sputtering, and further, chemical vapor deposition, atomic layer deposition, etc. can be applied.

〔Manufacturing process〕
FIG. 5 is a flowchart showing the manufacturing process of the polarizer 4. In this manufacturing process, the base material 15 is provided by a long transparent film material wound on a roll. In this manufacturing process, while the base material 15 is being pulled out from the roll and conveyed, a concavo-convex shape is formed on the surface of the base material 15 in the concavo-convex shape forming step SP2.

More specifically, in this unevenness forming step, as shown in FIG. 6(A), first, after coating the base material 15 with the coating liquid of the ultraviolet curable resin, fine unevenness is formed on the peripheral side surface. While the base material 15 is pressed and conveyed to the roll plate which is the mold for making, the ultraviolet curable resin is cured by irradiating the ultraviolet light, and then the cured ultraviolet curable resin is applied to the base material 15. Peel from the roll plate together with. As a result, in this step, as shown in FIG. 6B, the fine concavo-convex shape formed on the peripheral side surface of the roll plate is transferred, and the concavo-convex shape is formed on the surface of the base material 15 by repeating the concave grooves 11. To do. In this embodiment, the concave groove 11 is formed by using the roll plate 30 in which the ridges are formed by the direction extending in the circumferential direction, and thus the concave groove 11 is extended so as to extend in the longitudinal direction of the base material 15. By making the direction of extension of the concave groove 11 parallel to the slow axis direction of the base material 15, and the first and second directions with respect to the slow axis direction of the base material 15. The metal linear portions 12 and 13 are formed so that the extending directions thereof are parallel to each other.

Subsequently, in the manufacturing process of the polarizer 4, an adhesion layer preparation process SP3 is provided as needed, and in the adhesion layer preparation process SP3, the adhesion layer is formed on the surface of the imprinted resin layer 16 having the uneven shape thus manufactured. 17 is manufactured (FIG. 6C). More specifically, in this embodiment, the SiO _x layer is formed by sputtering.

Subsequently, in this manufacturing process, in the metal linear part manufacturing process SP4, as shown in FIG. 6D, a metal material is deposited on the entire surface of the concave-convex shaped surface in which the concave grooves 11 are manufactured by vapor deposition, sputtering, or the like. Deposit. Here, when the metal material is deposited on the concave-convex surface formed with the concave grooves 11 in this manner, the incoming metallic material is sequentially deposited at the tops between the concave grooves 11 according to the concave-convex shape, and the first metal is deposited. Thus, the metal linear portion 12 is formed. On the other hand, the metal material reaching the concave groove 11 enters the concave groove 11 and is deposited on the bottom surface, and as a result, the second metal linear portion 13 is formed. Thereby, in this embodiment, the first and second metal linear portions 12 and 13 are manufactured.

When the metal material is deposited in this manner to produce the first and second metal linear portions 12 and 13, subsequently, this manufacturing process is performed between the first metal linear portions 12 adjacent to each other by the etching process SP5. The void width S is enlarged.

That is, when the metal material is deposited by vapor deposition, sputtering, or the like as described above, the metal material adheres also to the wall surface of the concave groove 11 between the first and second metal linear portions 12 and 13, The metal material adhered to the wall surface is extremely small in amount and thin, so that the metal linear portions 12, 13 do not function as the metal material layer, and the metal linear portions 12, 13 are adjacent to each other in the width direction. Insulation is secured between the polarizer 13 and the polarizer 4, and the transmittance of the polarizer 4 is ensured by the plane of polarization.

However, for example, in the case of depositing a metal material by vapor deposition, as shown in FIG. 6E, in the first metal linear portion 12, the metal material grows not only in the thickness direction but also in the width direction. As a result, the gap width S between the first metal linear portions 12 may be extremely reduced. When the void width S is extremely reduced in this way, the aperture ratio in the first metal linear portion 12 (the ratio of the void width S in the repeating direction of the metal linear portion 12) is reduced, and as a result, the transmittance is reduced. Will be reduced.

Thereby, in this embodiment, the aperture ratio is increased by etching using the etching liquid. FIGS. 7A and 7B are characteristic curve diagrams showing changes in characteristics due to this etching. In FIG. 7, Tp and Ts are transmittances in the transmission axis direction and the absorption axis direction, respectively, and Rp and Rs are reflectances in the transmission axis direction and the absorption axis direction, respectively. In addition, the pitch P is 64 nm, the depth of the concave groove 11 is 60 nm, the thickness T (=T1, T2) of the metal linear portions 12 and 13 is 40 nm, and the gap width S is 30 nm. The metal material is aluminum. In FIG. 7A, the gap width S between the adjacent first metal linear portions 12 is 20 nm at the minimum, and in this example, the change in the transmittance Tp in the transmission axis direction with the wavelength is remarkable, and the transmittance It turns out that itself is small. It can also be seen that the reflectance Rp in the transmission axis direction is also large.

On the other hand, FIG. 7(B) shows that the polarizer having the configuration shown in FIG. 7(A) was exposed to an etching solution (temperature 23° C.) of a sodium hydroxide aqueous solution having a concentration of 0.01 mol/l within a range of 40±5 seconds. It was dipped in. Thereby, the minimum width of the gap width S between the adjacent first metal linear portions 12 was changed to 36 to 40 nm, and the thickness T was changed from the original thickness to less than -3 nm. According to FIG. 7B, it is understood that the characteristics are improved and the transmittance can be sufficiently secured in the wide wavelength range of the visible light range. Although the thickness T of the metal linear portion 12 is also reduced by the etching process, the gap width S can be expanded faster than the reduction of the thickness T. However, if the etching time is too long, the thickness of the second metal linear portion 13 becomes thin and the optical characteristics deteriorate, and in particular, the reflectance Rs in the absorption axis direction sharply decreases. However, if the etching time is too short, the transmittance Tp in the transmission axis direction decreases. Thus, the etching time is preferably 10 seconds or more and 60 seconds or less when etching is performed at a liquid temperature of 15 degrees or more and 34 degrees or less with a sodium hydroxide aqueous solution having a concentration of 0.005 mol/l or more and 0.015 mol/l or less.

Instead of such wet etching, so-called dry etching may be used to widen the gap width S. Further, when the void width S is sufficiently secured in practical use, the etching step may be omitted. By this etching step, the metal material attached to the wall surface of the concave groove 11 is also wholly or partially removed, thereby improving the insulating property between the first and second metal linear portions 12 and 13 to improve the characteristics. Can be improved.

As a result of this etching treatment, as shown in FIG. 8, the thickness of the first metal linear portion 12 gradually decreases in the width direction due to the progress of etching, so that the width of the portion in contact with the adhesion layer 17 becomes concave. It is formed to have a teardrop-shaped cross-sectional shape that is equal to or less than the width of the top portion between the grooves and gradually increases in width as it goes away from the portion in contact with the adhesion layer 17. In addition, the metal linear portion 13 existing at the bottom of the concave groove is formed with a concave recess having an arc shape in a sectional view. Here, the teardrop shape of the metal linear part means that the whole is formed in an arc in the cross-sectional view of FIG. 8, and is larger than the width of the base of the metal linear part on the adhesion layer 17 side. It means a spindle shape that is wide and bulged.

In the etching, the width of the portion in contact with the adhesion layer 17 is equal to or less than the width of the top between the concave grooves by etching the entire circumference of the metal linear portion 12 thus manufactured almost uniformly, and Preferably, the first metal linear portion 12 is made to have a teardrop-shaped cross-sectional shape that is narrower than the width of the top portion between the concave grooves and gradually increases in width as it moves away from the portion in contact with the adhesion layer 17. It should be noted that this makes it possible to confirm the execution of the etching treatment when the teardrop shape is produced. If the etching time becomes longer, the thickness of the second metal linear portion 13 also becomes thinner due to the etching, but in this case, the thickness becomes thinner toward the central portion.

When the metal linear parts 12 and 13 are manufactured in this manner, in this manufacturing process, the polarizer winding body is wound up on a roll, and the polarizer winding body is conveyed to the subsequent processing step to be linearly polarized light. Integration processing with a board, cutting processing, etc. are performed. The polarizer 4 may be cut into a desired shape and then integrated with the linear polarizing plate 7.

[Lamination process]
Here, the linear polarizing plate 7 by the sheet polarizer is stretched and produced, and as a result, the winding body 36 of the linear polarizing plate 7 provided by the roll has a transmission axis direction indicated by an arrow in FIG. The width direction is the transmission axis direction. In this embodiment, in the manufacturing process of FIG. 6, the concave groove 11 is formed by using the roll plate 30 in which the ridges are formed by the direction extending in the circumferential direction, and the groove 11 is extended in the longitudinal direction of the base material 15. By forming the concave groove 11 as described above, the extending direction of the first and second metal linear portions 12 and 13 is parallel to the slow axis direction of the base material 15. Thus, the polarizer 4 is manufactured in the shape of a long film so that the width direction of the base material 15 becomes the transmission axis direction.

In the laminating step, while pulling out and transporting the polarizer 4 from the winding body 35 of the polarizer 4 having the long film shape, the linear polarizing plate 7 having the same long film shape is drawn from the linear polarizing plate winding body 36. Then, the sheets are laminated and integrated, and then the sheet is cut into a rectangular shape suitable for arrangement in the liquid crystal cell 5.

As described above, the transmission axis direction was set so as to correspond to the transmission axis direction of the linear polarizing plate, and the transfer film and the polarizer were produced, and the linear polarizing plate was laminated and integrated in a state of a long film shape. After that, by cutting the sheet, the production can be performed more efficiently.

[Roll version]
FIG. 10 is a diagram for explaining the roll plate. The roll plate 30 is a mold for molding in which a fine concavo-convex shape is formed on the peripheral side surface, and the fine concavo-convex shape is formed on the peripheral side surface by a ridge corresponding to the concave groove 11. In this embodiment, the ridge is formed to have a width corresponding to the groove width of the concave groove 11 so as to extend in the circumferential direction, so that the ridge is subjected to a shaping process to extend in the longitudinal direction of the base material 15. The concave groove 11 is formed in the.

The roll plate 30 has a base material 31 formed in a cylindrical shape or a cylindrical shape made of a metal material that can be easily cut. In this embodiment, a copper pipe material is applied to the base material 31. In this manufacturing process, in the smoothing process, after the peripheral side surface of the base material 31 is smoothed by cutting the peripheral side surface of the base material 31 using a cutting tool, electrolysis is performed by a combination of electrolytic elution action and abrasive action by abrasive grains. The peripheral side surface of the base material 31 is made into a super-mirror surface by the composite polishing method.

Subsequently, in this manufacturing process, in the cutting process, after mounting the base material 31 on the cutting device, the tip of the cutting tool 32 is pressed against the peripheral side surface of the base material 31, and in this state, the base material 31 is attached as indicated by arrow B. While rotating, the bite 32 is moved in the direction along the pipe axis of the base material 31 as indicated by the arrow C, whereby the peripheral side surface of the base material 31 is spirally cut. As a result, in this manufacturing process, a ridge corresponding to the concave groove having a rectangular cross section extending in the circumferential direction is formed on the peripheral side surface of the base material 31. The tip of the cutting tool 32 is formed in a comb-like shape so that a plurality of concave grooves can be manufactured in parallel at the same time, which shortens the time required to manufacture the roll plate in this step. The method for manufacturing the cutting tool 32 having such a fine comb tooth shape is not particularly limited, but high energy beam processing, lithography processing, chemical Et, or precision cutting method generally known as a fine precision processing method for achieving these is used. It can be appropriately selected and can be produced by freely combining these.

According to the above configuration, it is possible to produce a concavo-convex surface by a shaping process by a method of continuously unwinding from the winding body and winding, and to secure sufficient reliability. Products can be produced efficiently.

Further, since the first metal linear portion has a teardrop-shaped cross-sectional shape in which the width gradually increases, a metal material is deposited to form the first metal linear portion, and the first metal linear portion is formed. When the space between the linear portions is so narrow that sufficient characteristics cannot be ensured, the space between the first metal linear portions is expanded by etching to secure the characteristics. It can handle light.

Further, since the second metal linear portion made of a metal material extending along the concave groove is provided at the bottom of the concave groove, the metal wire having the two-layer structure of the first and second metal linear portions is formed. It is possible to manufacture a polarizer having a rib portion.

Further, since the extending direction of the concave groove is the slow axis direction of the base material, the base material can be arranged so as to function in a direction that assists reflection and transmission by the metal linear portion, thereby further improving efficiency. The incident light can be processed well.

In addition, at least the shaping treatment is performed by forming a first metal linear portion by depositing a metal material after forming a concave-convex surface by performing a shaping treatment using a roll plate while pulling out the base material from the roll. As described above, a surface of a product having a large area can be produced by performing the shaping treatment continuously by unwinding from the winding body and performing the winding method so that a polarizer can be produced. Can be produced efficiently.

Further, by providing an etching process for etching the metal material deposited on the surface of the uneven surface, the gap between the first metal linear portions narrowed by depositing the metal material is expanded to secure the aperture ratio. Therefore, incident light can be processed with sufficient characteristics.

[Other Embodiments]
The specific configuration suitable for carrying out the present invention has been described above in detail. However, the present invention variously combines the above-described embodiments without departing from the spirit of the present invention, and further, the configuration of the above-described embodiment. Can be variously changed.

That is, in the above-described embodiment, the case where the recessed groove is formed by the rectangular cross section is described, but the present invention is not limited to this, and as shown in FIG. 11A, the opposing wall surfaces are tapered taper surfaces. The concave groove may be formed with a wedge-shaped cross-section, or as shown in FIG. 11B, the concave groove may be formed with a cross-sectional shape that is a sine wave-shaped uneven surface. The shape of can be applied.

Further, in the above-described embodiment, the case where the polarizer is configured by the two-layer structure of the first and second metal linear portions has been described, but the present invention is not limited to this, and only the first metal linear portions are used. You may produce a polarizer by 1 layer structure. In this case, as compared with the above-described embodiment, the depth of the recessed groove is made deeper than the groove width of the recessed groove, or the deposition direction of the metal material is changed so that the top portion between the recessed grooves is formed. In comparison, the amount of metal material deposited in the recessed groove is reduced, whereby the second metal linear portion is formed with a thickness smaller than that of the first metal linear portion. Then, by performing an etching process, the second metal linear portion can be removed and the first metal linear portion can be left, so that the polarizer can be manufactured.

Further, in the above-described embodiment, the case where the polarizer according to the present invention is arranged between the liquid crystal cell and the backlight has been described in the liquid crystal display device, but the present invention is not limited to this, and for example, a metal linear portion may be provided. It may be arranged in place of the linear polarizing plate that constitutes the liquid crystal cell by being manufactured by a multilayer structure so as to sufficiently suppress the reflectance.

Further, in the above-described embodiment, the case where the present invention is applied to the image display device related to the liquid crystal display device has been described, but the present invention is not limited to this, and may be applied to the image display device by the projector, and various configurations are possible. Can be widely applied to.

DESCRIPTION OF SYMBOLS 1 Image display device 2 Liquid crystal display panel 3 Backlight 4 Polarizer 5 Liquid crystal cell 6, 7 Linearly polarizing plate 10 Transparent member 11 Recessed groove 12, 13 Metal linear part 15 Base material 16 Adhesive resin layer 17 Adhesive layer 30 Roll plate

Claims (3)

In a polarizer that limits the transmission of incident electromagnetic waves according to the plane of polarization,
On one surface of the substrate made of a transparent film material, a concave-convex surface is formed by repeating concave grooves at a pitch of the shortest wavelength or less of a wavelength band that limits transmission,
At least a top portion between the concave grooves is provided with a first metal linear portion made of a metal material and extending along the concave grooves,
The first metal linear portion,
The width of the portion in contact with the top between the recessed grooves is not more than the width of the top between the recessed grooves,
Ri sectional shape der teardrop shape width gradually increases as the distance from the portion contacting with the top between the concave groove,
Furthermore, a second metal linear portion made of a metal material and extending along the concave groove is provided at the bottom of the concave groove,
The second metal linear portion is a polarizer in which the thickness is smaller in the central portion of the concave groove . The extending direction of the concave groove is the slow axis direction of the base material.
The polarizer according to claim 1 . The polarizer according to any one of claims 1 and 2 , wherein an adhesive layer that strengthens an adhesive force with the first metal linear portion is provided on a surface of the uneven surface.

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