JP2010250289A - Wire grid polarizing plate and method of manufacturing the same, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wire grid polarizing plate which has a heater function added thereto neither requiring an increase in the thickness and nor reducing the light transmittance, to provide a method of manufacturing the same, and a liquid crystal display. <P>SOLUTION: The wire grid polarizing plate 50 includes a resin substrate 1 having grid-like projections 1a on a surface thereof, a dielectric layer 2 formed on a region including the grid-like projections 1a of the resin substrate 1, and metal wires 3 formed on the grid-like projections 1a covered with the dielectric layer 2 and on the dielectric layer 2. The metal wires 3 have end parts connected to each other to constitute metal portions 9a, and the metal portions 9a may be energized with current, so that the metal wires serve as a heater. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a wire grid polarizing plate having a fine concavo-convex lattice, and more particularly to a conductive wire grid polarizing plate capable of generating heat electrically and a method for manufacturing the same.

  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 narrow pitch is useful not only in the semiconductor field but also in the optical field.

  For example, a linear metal wire that is parallel to each other and formed at a specific interval (period) is a diffraction grating if the period is larger than the wavelength of incident light, for example, visible light of 400 nm to 700 nm. . On the other hand, if the period is considerably smaller than the wavelength of visible light, for example, about ½ or less, the metal wire reflects almost the electric field vector component that oscillates parallel to the metal line, and the vertical electric field Since most of the vector component is transmitted, it can be used as a polarizing element that produces a single polarized light. In fact, such metal wires are used as wire grid polarizers (also referred to as wire grid polarizers) for purposes such as various liquid crystal display devices, polarization beam splitters, polarization reflectors, and optical isolators. The wire grid polarizing plate is desirable also from the viewpoint of effective use of light because light that does not transmit can be reused by using a reflector or the like.

  By the way, when the wire grid polarizing plate is used in a liquid crystal display device, particularly in an environment where it is exposed to the outside air, for example, in an in-vehicle liquid crystal panel, or when used in a cold region, it becomes cloudy. In such a case, various inconveniences such as deterioration in display performance and reduction in response speed are caused. Therefore, conventionally, in a liquid crystal display device incorporating a conventional polarizing plate, a transparent panel heater for heating is laminated on the polarizing plate to deal with the above-described disadvantages (for example, patents). Reference 1 and Patent Document 2).

JP 2006-106064 A JP 2001-242439 A

  However, in the structure in which the transparent panel heater is laminated on the polarizing plate, the thickness of the entire apparatus is increased by the thickness of the panel heater, which is an obstacle to downsizing the apparatus. Moreover, even if it is a transparent panel heater, light transmittance will fall by laminating | stacking this.

  The present invention has been made in view of the above points, and provides a wire grid polarizing plate to which a heater function is added without increasing the thickness dimension and without decreasing the light transmittance, a manufacturing method thereof, and a liquid crystal display device. The purpose is to provide.

  The wire grid polarizing plate of the present invention includes a resin base material having a lattice-like convex portion on a surface, a dielectric layer formed on a region including the lattice-like convex portion of the resin base material, and the dielectric layer. And a metal wire formed on the grid-like convex portion that is covered, and a metal portion in which ends of the metal wire are connected to each other can be energized.

  According to this configuration, by energizing the metal part where the ends of the metal wire are connected, the metal wire generates heat and functions as a heater. According to this configuration, since it is not necessary to attach a heater separately, a heater function can be added without increasing the thickness dimension and without reducing the light transmittance.

  The liquid crystal display device of the present invention comprises a liquid crystal panel, illumination means for irradiating the liquid crystal panel with light, and the wire grid polarizing plate disposed between the liquid crystal panel and the illumination means. Features.

  The manufacturing method of the wire grid polarizing plate of the present invention includes a first step of forming a dielectric layer on a region including a lattice-shaped convex portion of a resin base material having a lattice-shaped convex portion on the surface; The method includes a second step of forming a flat portion by partially lowering the convex portion, and a third step of forming a metal wire on the dielectric layer including the flat portion.

  According to this method, the end of the grid-like convex part is partially lowered to form a flat part, and metal is deposited on the flat part to form a metal part that connects the ends of the metal wires. It is possible to energize the metal part. In this case, the steps other than the step of forming the flat portion are the same as the manufacturing steps of a normal wire grid polarizing plate, so that the wire grid polarizing plate with a heater function can be manufactured by a simple step.

  According to the present invention, a resin base material having a lattice-like convex portion on the surface, a dielectric layer formed on a region including the lattice-like convex portion of the resin base material, and the dielectric layer is covered. A metal wire formed on the grid-like convex portion, and the metal portion where the ends of the metal wire are connected to each other can be energized, so that the light transmittance is increased without increasing the thickness dimension. A wire grid polarizing plate with a heater function can be realized without lowering the temperature.

(A) is a schematic sectional drawing which shows a part of wire grid polarizing plate which concerns on embodiment of this invention, (b) shows the metal part of the wire grid polarizing plate which concerns on embodiment of this invention. It is a schematic sectional drawing. (A)-(c) is sectional drawing for demonstrating the method to obtain the to-be-stretched member which has an uneven | corrugated lattice in the manufacturing method of the wire grid polarizing plate which concerns on embodiment of this invention. (A) And (b) is a top view of the to-be-stretched member before and behind free end uniaxial stretching for demonstrating the manufacturing method of the wire grid polarizing plate which concerns on embodiment of this invention. (A)-(d) is sectional drawing for demonstrating the manufacturing method of the wire grid polarizing plate which concerns on embodiment of this invention. It is a figure for demonstrating the effect | action of the wire grid polarizing plate which concerns on embodiment of this invention. It is the schematic of a liquid crystal display device provided with the wire grid polarizing plate which concerns on embodiment of this invention. It is a figure for demonstrating the effect | action of the wire grid polarizing plate which concerns on embodiment of this invention. It is a figure for demonstrating the effect | action of the wire grid polarizing plate which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The wire grid polarizing plate according to the present invention basically includes a step of forming a dielectric layer on a region of the resin base material having a lattice-shaped convex portion on the surface thereof, the region including the lattice-shaped convex portion, and the dielectric Forming a metal wire on the layer. In this case, the flat portion is formed by partially lowering the ends of the lattice-like convex portions of the resin base material on which the dielectric layer is formed.

  First, the resin base material, dielectric material, and metal wire which comprise the wire grid polarizing plate which concerns on this invention are demonstrated.

  FIG. 1A is a schematic cross-sectional view showing a part of a wire grid polarizer 50 according to an embodiment of the present invention, and FIG. 1B is a wire grid polarizer according to an embodiment of the present invention. It is a schematic sectional drawing which shows a part of 50 metal parts.

  The resin used for the resin substrate 1 may be a resin that is substantially transparent in the visible light region. For example, polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin resin (COP), cross-linked polyethylene resin, polyvinyl chloride resin, polyarylate resin, polyphenylene ether resin, modified polyphenylene ether resin, polyetherimide resin, polyether Amorphous thermoplastic resins such as sulfone resin, polysulfone resin, polyether ketone resin, polyethylene terephthalate resin (PET), polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal Examples thereof include crystalline thermoplastic resins such as resins and polyamide resins, and ultraviolet curable resins and thermosetting resins such as acrylics, epoxies, and urethanes. Moreover, it can also be set as the structure which combined the ultraviolet curable resin and thermosetting resin which are the resin base materials 1 as a base material, inorganic board | substrates, such as glass, the said thermoplastic resin, and a triacetate resin.

  As shown in FIG. 1 (a), the pitch of the grid-shaped convex portions 1a of the resin base material 1 is 150 nm or less, preferably 80 nm to 150 nm, considering the polarization characteristics over a wide band in the visible light region. The smaller the pitch is, the better the polarization characteristics are. However, for visible light, sufficient polarization characteristics can be obtained at a pitch of 80 to 150 nm.

  When the thermoplastic resin is used for the resin base material 1, the pitch of the lattice-shaped convex portions 1 a may be controlled by adjusting the conditions of the stretching process that is performed after the lattice-shaped convex shape is imparted to the resin base material 1. it can. In the present invention, the pitch P of the grid-like convex portions 1a of the resin substrate 1, the pitch of the dielectric layer 2, and the pitch of the metal wires 3 are substantially equal to the pitch of the wire grid of the present invention, and the same pitch. P may be taken.

The height H ₁ of the resin substrate 1 grid-shaped convex portions 1a is or to obtain a good optical properties, enhance the adhesion between the substrate and the dielectric layer 2, the grid-shaped convex portions of the dielectric layer 2 Considering the selective high lamination on 1a, it is preferably 0.5 to 2.0 times, more preferably 1.0 to 2.0 times the pitch of the grid-like convex portions 1a. .

  There is no restriction | limiting in the cross-sectional shape of the recessed part 1c of the fine uneven | corrugated grating | lattice formed of the grid | lattice-like convex part 1a of the resin base material 1 or several grid | lattice-like convex part. 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. In addition, the curved part should just be a curved curve, for example, the shape which has a constriction in a convex part is also included in a sine wave form. Further, from the viewpoint of easily covering the convex portion of the resin base material and at least a part of the side surface thereof with the dielectric, it is preferable that the end portion, the apex, or the valley of the shape is curved with a gentle curvature. Further, from the viewpoint of increasing the adhesion strength between the resin base material 1 and the dielectric layer 2, it is more preferable that these cross-sectional shapes are sinusoidal.

  The dielectric constituting the dielectric layer 2 may be a dielectric that is substantially transparent in the visible light region. A dielectric material having strong adhesion between the material constituting the resin substrate 1 and the metal constituting the metal wire 3 can be suitably used. For example, silicon (Si) oxide, nitride, halide, carbide alone or a composite thereof, aluminum (Al), chromium (Cr), yttrium (Y), zirconia (Zr), tantalum (Ta), Metal oxides such as titanium (Ti), barium (Ba), indium (In), tin (Sn), zinc (Zn), magnesium (Mg), calcium (Ca), cerium (Ce), copper (Cu) , Nitrides, halides, carbides or composites thereof (dielectrics in which other elements, simple substances, or compounds are mixed in a dielectric substance) can be used.

  In the present invention, in order to obtain sufficient adhesion strength between the resin base material 1 and the metal wire 3, the dielectric layer 2 covers at least a part of the lattice-like convex portion 1a and the side surface 1b of the resin base material 1. It is preferable that it is provided. From the viewpoint of improving the adhesion between the grid-shaped convex portion 1a and the dielectric layer 2, and from the viewpoint of suppressing the low molecular weight volatiles generated from the resin base material 1, the dielectric layer 2 covers the entire fine uneven grating. It is more preferable to coat. In the present invention, in the fine concavo-convex lattice shape, a thicker covering or higher layer of a dielectric or metal is called a selective lamination mainly on the convex portion than the side surface 1b or the concave portion 1c of the convex portion.

The thickness (hereinafter referred to as the height of the dielectric layer 2) of the dielectric layer 2 covering the lattice-shaped convex portion 1a of the resin base material 1 is determined between the optical characteristics and the resin base material and the metal wire. From the viewpoint of adhesion strength, structural strength of the wire grid, time required for coating, selective lamination of metal wires, and the like, the thickness is preferably 2 nm to 200 nm. In particular, the height of the dielectric layer on the lattice-shaped convex portion of the resin base material is preferably 5 nm to 150 nm. Further, the height difference H ₂ (hereinafter referred to as the height difference H ₂ ) between the convexity peak and the concave valley of the concavo-convex grating formed by the dielectric layer 2 covering the grid-like convex part 1a of the resin base material 1 is as follows. Considering the structural strength and optical characteristics of the metal wire 3 as a pedestal, the thickness is preferably 100 nm to 300 nm, and more preferably 150 nm to 250 nm. However, as described later, instead of adding a step of crushing the dielectric layer 2 to reduce its height, the deposition height of the dielectric layer 2 is kept low at this stage (it can be kept low as will be described later). Due to the height of the dielectric layer 2, the metal wire 3 is simultaneously deposited on the lattice-like convex portion 1 a on which the dielectric layer is deposited (covered) and at least part of the concave portion 1 c between the lattice-like convex portions 1 a It is also possible to regulate the height so that it can be controlled.

The width of the convex portion of the concavo-convex lattice formed by covering the lattice-shaped convex portion 1a of the resin base material at the height of one half of the height difference H ₂ is the width W ₂ of the dielectric layer (hereinafter referred to as the dielectric layer width W ₂ ) , Referred to as the width of the dielectric layer). The width W ₂ of the dielectric layer 2, to ensure that in terms of structural strength of the optical properties and the wire grid, a 0.6-fold from 0.3 times the pitch of the resin substrate 1 grid-shaped convex portions 1a It is preferred, when using the oblique lamination method which will be described later during lamination of the metal, the width W ₂ of the dielectric layer is 0.5 times 0.1 times the pitch of the grid-shaped convex portions of the resin substrate is preferable.

  As a method for forming the dielectric layer 2 on the region including the lattice-shaped protrusions 1a of the resin base material 1 having the lattice-shaped protrusions 1a, an appropriate method is selected depending on the material constituting the dielectric layer 2. For example, a physical vapor deposition method such as a sputtering method or a vacuum vapor deposition method can be suitably used. The sputtering method is preferable from the viewpoint of adhesion strength.

  The metal constituting the metal wire 3 is preferably a metal having high light reflectance in the visible light region and good adhesion to the material constituting the dielectric layer 2. For example, it is preferably composed of aluminum (Al), silver, or an alloy thereof. From the viewpoint of cost, it is more preferable that it is made of Al or an alloy thereof.

The width W ₃ of the metal wire 3 is 0.2 to 0.6 times the pitch of the grid-like convex portions 1a of the resin base material 1 from the viewpoint of optical characteristics such as the degree of polarization and transmittance and the structural strength of the wire grid. Preferably there is. The thickness H ₃ (hereinafter referred to as the height of the metal wire 3) of the metal wire 3 formed on the convex portion of the concave and convex lattice formed by the dielectric layer 2 covering the lattice-like convex portion 1 a of the resin base material 1 is Considering the optical characteristics, the adhesion strength between the metal wire 3 and the dielectric layer 2, the structural strength of the wire grid polarizer, and the processing time required for lamination, the thickness is 120 nm to 220 nm, preferably 140 nm to 200 nm. The ratio H ₃ / W ₃ (aspect ratio) of the height H ₃ of the metal wire 3 to the width W ₃ of the metal wire 3 is preferably 2 to 5, and more preferably 2 to 4.

  As a method of laminating a metal on the dielectric layer 2 to form the metal wire 3, sufficient adhesion can be obtained between the material constituting the dielectric layer 2 and the metal constituting the metal wire 3. If it is a method, it will not specifically limit. For example, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, or an ion plating method can be suitably used. Among them, a method is preferable in which the metal can be selectively laminated on the convex portion (on 1b) and the concave portion (on 1c) of the dielectric layer 2 or selectively biased to one side surface of the convex portion of the dielectric layer 2. An example of such a method is a vacuum deposition method.

  FIG.1 (b) is a schematic sectional drawing which shows the metal part to which the edge parts of the grid | lattice-like convex part metal wire of the wire line arranged in parallel were connected. After the dielectric layer 2 is formed on the resin base material 1, if the height of the convex portion in the metal portion forming region is lowered, for example, when the convex portion is crushed, the dielectric layer 2 is formed in the concave portion 1 c of the resin base material 1. Is embedded to form the flat portion 2a. And if the metal of the metal wire 3 is deposited on it, a metal layer will be formed. Thereby, the metal part 9a to which the ends of the wire wires arranged in parallel are connected is formed.

  In this way, as shown in FIG. 5, when the metal wires 3 arranged side by side are connected by the metal portion 9a and energized to the metal portion 9a, the metal wire 3 generates heat and exhibits a heater function. . In addition, a desired resistance value can be obtained by connecting the metal wire portions in series as shown in FIG. At this time, the area of the series portion can be adjusted while measuring the resistance value. As shown in FIG. 7, in the case where six series portions where metal wires are connected in series are provided, if the resistance value between the blocks is 3Ω, the series resistance is 18Ω in total. Since it can be designed arbitrarily according to the heater specifications, such as block length, width, number of blocks, series, parallel connection, etc., a configuration as shown in FIG. 8 may be adopted. FIG. 8 shows a case where a wire wire is provided obliquely with respect to an arbitrary side in a rectangular wire grid polarizer. For example, when the display unit of the liquid crystal display device is provided in a rectangular shape and the wire lines of the wire grid polarizer are arranged obliquely with respect to an arbitrary side of the rectangular display unit, the wire grid polarization shown in FIG. A board can be applied.

  Here, when the flat portion is formed, the case where the height of the convex portion is lowered after forming the dielectric layer 2 on the resin base material 1 is described, but the present invention is not limited to this, You may provide a flat part by making the height of the grid-like convex part 1a of the resin base material 1 low. In this case, a dielectric layer is formed on the flat portion, and a metal layer is laminated thereon. Further, without forming a flat portion, it is possible to produce an electrode portion by pressing an anisotropic conductive film or conductive paste, and to allow the metal portion to function as a heater by energizing the electrode portion. The electrode portion can be manufactured by cutting the grid pattern (fine irregularities) of the mold by laser processing or the like and forming an AL solid film. This is a processing and electrode formation method unique to WGF using fine irregularities.

  The electrode portion can be a terminal extraction portion, and an anisotropic conductive film can be used as the terminal extraction portion. When the metal wire grid is Al, the contact resistance of the connecting portion is increased by the oxide film on the surface. Therefore, the conductive material of the anisotropic conductive film contains Ni, Ag, Cu, Sn, etc. Those that break the oxide film on the surface of the wire grid are preferable.

Next, a method for obtaining a resin base material having a grid-like convex portion of the present invention will be described.
There is no particular limitation on the method for obtaining the resin base material 1 having the grid-like convex portion 1a of the present invention, but the method described in Japanese Patent Application Laid-Open No. 2006-224659 of the present applicant (in the present invention, Method I, Method II, The outline is explained separately).

  Specifically, as a method I for obtaining the resin base material 1 having the grid-like convex portions 1a having a pitch of 150 nm or less of the present invention, a stretched member having a rugged grid with a pitch of 100 nm to 100 μm on the surface is used. Produced by free-end uniaxial stretching in a direction substantially parallel to the longitudinal direction with the width of the stretched member in a direction substantially perpendicular to the longitudinal direction (direction parallel to the lattice of the grid-like convex portion) being made free can do. As a result, the pitch of the convex portions of the concavo-convex grid of the stretched member is reduced, and a resin base material (stretched member) having a fine concavo-convex grid with a pitch of 150 nm or less is obtained. The pitch of the concavo-convex grid is set in the range of 100 nm to 100 μm, but can be appropriately changed according to the required pitch of the fine concavo-convex grid and the draw ratio.

  Here, the stretched member is transparent such as a plate-like body, a film-like body, or a sheet-like body composed of the above-described amorphous thermoplastic resin or crystalline thermoplastic resin as the resin base material 1 used in the present invention. Examples of the resin base material can be given. The thickness and size of the stretched member are not particularly limited as long as the uniaxial stretching process is possible.

In addition, in order to obtain a stretched member having a concavo-convex lattice with a pitch of 100 nm to 100 μm on the surface, a mold having a concavo-convex lattice with a pitch of 100 nm to 100 μm formed by an interference exposure method using laser light or a cutting method is used. The concavo-convex lattice shape may be transferred to the stretched member by a method such as hot pressing. The interference exposure method is an exposure method using interference fringes formed by irradiating laser light of a specific wavelength from two directions of angle θ ′, and is a laser used by changing angle θ ′. It is possible to obtain a concavo-convex lattice structure having various pitches within a range limited by the wavelength of. As the laser that can be used for the interference exposure, limited to laser _{TEM 00} mode, as the ultraviolet light laser capable lasing of _{TEM 00} mode, an argon laser (wavelength 364 nm, 351 nm, 333 nm) and, of YAG laser fourth harmonic ( Wavelength 266 nm).

  In the uniaxial stretching treatment in the present invention, first, the width direction of the stretched member (direction perpendicular to the longitudinal direction of the concavo-convex lattice) is set free, and the longitudinal direction of the concavo-convex lattice of the stretched member is changed to a uniaxial stretch treatment apparatus. Fix it. Subsequently, after heating to an appropriate temperature at which the stretched member softens and holding it for an appropriate period of time, the pitch of the target fine concavo-convex lattice is set at an appropriate drawing speed in one direction substantially parallel to the longitudinal direction. Stretching is performed up to a stretching ratio corresponding to. Finally, the member to be stretched is cooled to a temperature at which the material is cured in a state where the stretched state is maintained, thereby obtaining a resin base material having a grid-like convex portion having a pitch of 150 nm or less. As an apparatus for performing this uniaxial stretching process, an apparatus for performing a normal uniaxial stretching process can be used. Further, the heating condition and the cooling condition are appropriately determined according to the material constituting the stretched member.

  The method II of obtaining a resin substrate having a grid-like convex part with a pitch of 150 nm or less according to the present invention is the above-mentioned resin substrate used in the present invention by using a mold having a fine concavo-convex grid with a pitch of 150 nm or less on the surface. This is a method of transferring and molding a fine concavo-convex lattice on the surface of the substrate. Here, in the mold having a fine concavo-convex lattice with a pitch of 150 nm or less on the surface, the resin base material having a grid-like convex part with a pitch of 150 nm or less obtained by the method I is sequentially subjected to a conductive treatment, a plating treatment, and a resin base. It can be produced by applying a material removal treatment.

  According to this method, since a mold having a grid-like convex part with a pitch of 150 nm or less is already used, a resin substrate having a grid-like convex part with a pitch of 150 nm or less used in the present invention without going through a complicated stretching process. Can be mass-produced. Further, by appropriately combining and repeatedly using Method I and Method II, it is possible to produce a finer concavo-convex grid from a concavo-convex grid having a relatively large pitch.

Next, the manufacturing method of the wire grid polarizing plate of this invention is demonstrated.
Here, the method for producing the wire grid polarizer of the present invention by the above method I and method II will be described with reference to the drawings. 2A to 2C are cross-sectional views for explaining a method for obtaining a stretched member having the concavo-convex lattice according to the present invention, and FIGS. 3A and 3B show the present invention. It is the figure seen from the upper surface before and behind the free end uniaxial stretching of the stretched member having the concavo-convex lattice concerned. 4A to 4D are cross-sectional views for explaining a method of manufacturing a wire grid polarizer according to the embodiment of the present invention. FIG. 5 is a diagram showing a part of a wire grid polarizer obtained by the production method of the present invention.

  First, the process of obtaining the resin base material which has the lattice-shaped convex part used by this invention is demonstrated. First, a mold (stamper) 4 having an uneven lattice 4a with a pitch of 100 nm to 100 μm on the surface shown in FIG. The stamper 4 applies a resist material on a glass substrate by spin coating to form a resist layer, exposes the resist layer using an interference exposure method, and develops the resist layer. Thereby, a resist layer having a concavo-convex lattice with a pitch of 100 nm to 100 μm is obtained. Next, nickel or gold is sputtered on the resist layer to make the resist layer conductive. Further, nickel plating is performed on the sputtered metal to form a nickel plate. Finally, the stamper 4 having a concavo-convex grid with a pitch of 100 nm to 100 μm on the surface can be produced by peeling the nickel plate from the glass plate and removing the resist layer from the nickel plate. Note that the manufacturing method of the stamper 4 is not limited to the above method, and other methods may be used.

  Next, as shown in FIG. 2A and FIG. 2B, the uneven member 4a side of the stamper 4 is pressed against the member 5 to be stretched by a process such as hot pressing, and the uneven member 4a is pressed against the member 5 to be stretched. Transfer the pattern. The stretched member 5 can be produced by injection molding or extrusion molding when the constituent material is a thermoplastic resin. When the stamper 4 is removed, as shown in FIG. 2C, the stretched member 5 having the concavo-convex grid 5a to which the concavo-convex grid 4a of the stamper 4 is transferred is obtained.

  Next, a free end uniaxial stretching process is applied to the stretched member 5 with the width direction made free. That is, the stretched member 5 shown in FIG. 3A is uniaxially stretched in a free end in the arrow direction (a direction substantially parallel to the longitudinal direction of the concavo-convex lattice 5a). At this time, the material constituting the stretched member 5 is heated to a temperature at which the material is softened, the stretched member 5 is uniaxially stretched in a direction substantially parallel to the longitudinal direction of the fine concavo-convex lattice 5a, and the material is kept in a stretched state. The stretched member 5 is cooled to a curing temperature. In addition, these heating temperature and cooling temperature are suitably set with the material which comprises the to-be-stretched member 5. FIG.

  By this free end uniaxial stretching process, the stretched member 5 becomes longer in the arrow direction, and the width direction is reduced accordingly. As a result, as shown in FIG. 3B, a stretched member (stretched member) 5 'having a grid-like convex portion 5a' at a pitch of 120 nm or less is obtained (FIG. 4A). In addition, about a draw ratio, it sets suitably based on the pitch of the uneven | corrugated lattice of the to-be-stretched member to prepare, and the pitch of the fine uneven | corrugated lattice of the already-stretched member required.

  Next, a mold 6 is obtained using the stretched member 5 ′. Specifically, first, a metal film is formed on the surface of the stretched member 5 ′ on the side having the grid-like convex portions 5a ′ shown in FIG. 4A by, for example, vapor deposition, sputtering, electroless plating, or the like. Form and conduct. Next, a metal layer is formed on the conductive surface by electroplating or the like, so that a mold 6 is formed on the stretched member 5 'as shown in FIG. 4B. There is no restriction | limiting in particular in the thickness of a metal layer, According to the use of the metal mold | die 6, it sets suitably.

  Finally, by removing the stretched member 5 ′ from the mold 6, as shown in FIG. 4 (c), the mold 6 having the grid-like convex portions 6 a having a pitch of 120 nm or less can be obtained. it can. As a method for removing the stretched member 5 ′ from the mold 6, a method of physically peeling the mold 6 from the stretched member 5 ′ or a solvent in which only the material constituting the stretched member 5 ′ is dissolved is used. For example, a method of chemically peeling can be used.

  The mold 6 thus obtained has the grid-like convex portions 6a having a pitch of 120 nm or less, and this is used as the mold (master mold) of the method II as shown in FIG. 4 (d). In addition, the mold 6 (master mold) is pressed against, for example, a resin base material, and the lattice-shaped convex portions are transferred, so that the lattice-shaped convex portions 7a having a pitch of 150 nm or less used in the present invention are obtained. The resin base material 7 which has can be obtained. Considering the ease of forming a structure having a grid-like convex part on the surface of a resin base material, after applying an ultraviolet curable resin to the master mold, it is cured by irradiating with ultraviolet rays to release or thermosetting It is preferable to transfer the lattice-shaped convex portions by applying a heat-resistant resin to the master mold, followed by heat curing and releasing the mold.

  Next, using this mold, a dielectric layer is formed by covering at least part of the lattice-like convex portions 7a of the resin base material 7 and the side surfaces thereof with a dielectric. For example, silicon oxide may be coated on the lattice-like convex portions 7a of the resin base material 7 and at least a part of the side surfaces thereof with a thickness of 2 nm to 200 nm by a sputtering method. At this time, the dielectric layer is formed thicker on the lattice-shaped convex portions 7a than the side surfaces of the lattice-shaped convex portions 7a and the concave portions 7b between the lattice-shaped convex portions 7a. In the formation of the dielectric layer, it is preferable that the width of the upper portion of the lattice-like convex portion 7a is corrected to a shape such as an undercut shape wider than the lower portion. Thereby, a metal wire can be efficiently formed in a dielectric layer. As such a shape correction method, a reverse sputtering method or the like can be used.

  Next, the end of the convex portion covered with the dielectric layer is crushed to reduce the height of the dielectric layer. Thereby, the flat part 2a is formed as shown in FIG.1 (b). Thereafter, the metal wire 3 is formed by depositing a metal wire metal on the dielectric layer 2 including the flat portion 2a. For example, Al may be laminated by a vacuum deposition method so that the average thickness becomes 120 nm to 220 nm. Thereafter, the metal deposited in the recesses between the metal wires 3 (the recesses 1c in FIG. 1A) is removed by etching. The metal portion 9a deposited on the flat portion 2a during etching also decreases, but the metal deposited on the flat portion 2a is so cut that the connection between the ends of the wire wires arranged side by side is cut. It is important not to etch. Usually, in the process of removing the metal deposited in the recesses between the metal wires 3 (the recesses 1c in FIG. 1A) by etching, the connection between the ends of the wire lines is cut. It is not etched as much as possible.

  As shown in FIG. 5, the wire grid polarizing plate obtained in this way constitutes a plurality of wire lines so that the metal wires 9 extend substantially in parallel. Are connected to each other by a metal portion 9a, and the metal portion 9a can be energized. In this case, power is supplied from the power supply unit 10. As shown in FIG. 5, the energized portion may be partially energized by forming an electrode, or may be energized by forming an electrode over the entire end. As a result, a parallel circuit as shown in FIG. 5 is formed as the circuit. In forming the parallel circuit, the length and thickness of the energized portion can be appropriately formed and the resistance value can be determined according to the heater design.

  According to this configuration, the end portions of the metal wires are connected to form a metal portion, and by energizing the metal portion, the metal wire generates heat and functions as a heater. Further, according to this configuration, since it is not necessary to attach a heater separately, a heater function can be added without increasing the thickness dimension and without decreasing the light transmittance. That is, as shown in FIG. 5, the metal wire 9 has a polarization effect that almost reflects the electric field vector component E ′ that oscillates in parallel with the metal line, and almost perpendicularly transmits the electric field vector component E. Further, it also functions as a heater that generates heat by energizing the metal portion 9 a of the metal wire 9.

  In the method for producing a wire grid polarizing plate of the present invention, a dielectric layer is formed on a region of the resin base material having a lattice-like convex portion on the surface thereof, and the lattice-like convex portion is partially formed. Accordingly, a flat portion is formed, and a metal wire is formed on the dielectric layer including the flat portion. According to this method, it is possible to form a flat portion by partially lowering the grid-like convex portion and deposit metal on the flat portion, thereby forming a metal portion between the ends of the metal wire. is there. In this case, the steps other than the step of forming the flat portion are the same as the manufacturing steps of a normal wire grid polarizing plate, so that the wire grid polarizing plate with a heater function can be manufactured by a simple step.

  Next, the case where the wire grid polarizing plate 50 having the above configuration is used in a liquid crystal display device will be described. FIG. 6 shows an embodiment of a liquid crystal display device using the laminated wire grid polarizer 50 according to the embodiment of the present invention.

  The liquid crystal display device 100 shown in FIG. 6 includes a lighting device 111 such as a backlight that emits light, a laminated wire grid polarizing plate 50 disposed on the lighting device 111, and a laminated wire grid polarizing plate 50. The liquid crystal panel 132 and the polarizing plate 133 are mainly configured. That is, the laminated wire grid polarizing plate 50 according to the present invention is disposed between the liquid crystal panel 132 and the lighting device 111.

  The liquid crystal panel 132 is a transmissive liquid crystal panel, and is configured by sandwiching a liquid crystal material or the like between glass and a transparent resin substrate. In the liquid crystal display device of FIG. 6, description of various optical elements such as a polarizing plate protective film, a retardation film, a diffusion plate, an alignment film, a transparent electrode, and a color filter that are usually used is omitted.

  In the liquid crystal display device having such a configuration, the light emitted from the illumination device 111 enters from the base side of the resin base material 1 of the laminated wire grid polarizing plate 50 and passes through the liquid crystal panel 132 from the wire side to the outside. It is emitted (in the direction of the arrow in the figure). In this case, since the laminated wire grid polarizer 50 exhibits an excellent degree of polarization in the visible light region, a display with high contrast can be obtained. When higher contrast is required, light that enters (external) from the outside of the polarizing plate 133, that is, from the direction opposite to the lighting device 111, passes through the liquid crystal panel 132 and is transmitted by the laminated wire grid polarizing plate 50. In order to prevent the light from being reflected and returned to the outside of the liquid crystal panel 132 again, an absorption type polarizing plate 131 using a dichroic dye such as iodine is interposed between the laminated wire grid polarizing plate 50 and the liquid crystal panel 132. Is preferably inserted with the laminated wire grid polarizer 50 aligned with the polarization axis. In this case, the absorption type polarizing plate preferably has a high transmittance and may have a low degree of polarization.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims for patent.

DESCRIPTION OF SYMBOLS 1 Resin base material 1a, 7a Grid-shaped convex part 1c Concave part 2,8 Dielectric layer 2a Flat part 3,9 Metal wire 9a Metal part 10 Current supply part

Claims (3)

  A resin base material having a lattice-like convex portion on the surface, a dielectric layer formed on a region including the lattice-like convex portion of the resin base material, and the lattice-like convex portion covered with the dielectric layer A wire grid polarizer comprising: a metal wire formed on the metal wire, wherein the metal wire can be energized to a metal portion to which ends of the metal wire are connected.   It comprises a liquid crystal panel, illumination means for irradiating the liquid crystal panel with light, and the wire grid polarizing plate according to claim 1 disposed between the liquid crystal panel and the illumination means. Liquid crystal display device.   A first step of forming a dielectric layer on a region including the lattice-shaped convex portion of a resin base material having a lattice-shaped convex portion on the surface; and a flat portion by partially lowering the lattice-shaped convex portion A method of manufacturing a wire grid polarizer, comprising: a second step of forming; and a third step of forming a metal wire on the dielectric layer including the flat portion.

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