JP2010091621A - Absorptive wire-grid polarizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorptive wire-grid polarizer capable of increasing the availability of light rays on a backlight side, suppressing reflectivity for incident light on an external light side, and achieving sufficient color reproducibility and black display when being arranged in a display device such as an LCD in a polarizer which is excellent in durability, has high transmissivity and low reflectivity, and is stacked on a reflective wire grid polarizer. <P>SOLUTION: The absorptive wire-grid polarizer includes: a substrate having protrusion in a grid-like formation; and a layer composed of absorption type polarizing components formed on the protrusion of the substrate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an absorption wire grid polarizer.

  With the recent development of photolithography technology, it has become possible to form a fine structure pattern having a pitch at the wavelength level of light. Such a member or product having a pattern with a very small pitch is useful not only in the semiconductor field but also in the optical field (Non-Patent Document 1).

  For example, a wire grid in which conductor wires made of metal or the like are arranged in a lattice pattern at a specific pitch has a pitch that is considerably smaller than incident light (for example, visible light wavelength 400 nm to 800 nm). For example, if it is less than half, most of the electric field vector component light that oscillates in parallel to the conductor line is reflected, and almost no electric field vector component light perpendicular to the electric conductor line is transmitted. Can be used as a polarizer to produce a single polarization. Since this wire grid polarizer can reflect and reuse light that does not transmit, it is also desirable from the viewpoint of effective use of light.

  An example of such a wire grid polarizer is disclosed in Patent Document 1. The wire grid polarizer includes metal wires spaced at a grid period smaller than the wavelength of incident light. This wire grid polarizer has polarization characteristics that the electric field component reflects the polarization component (TE wave) parallel to the metal wire and transmits the polarization component (TM wave) perpendicular to the metal wire, and is often used as a beam splitter. Has been.

  However, since the polarization component is separated by reflection, there is a problem that it is difficult to apply the reflected polarization component to an unfavorable application. When the wire grid polarizer is disposed in a display device such as a liquid crystal display device, In the configuration disclosed in Patent Document 1, the metal wire reflects not only the light from the backlight side but also the light from the outside light side, so that sufficient color reproducibility and black display cannot be performed. was there.

Here, when the black light is displayed, the external light amount is I _in , the external light reflectance is R, and the backlight transmitted light amount is I _c .
(Black display light amount) = I _c + R · I _in
And given. To provide sufficient black display because the better the black display light quantity is small, decreases the backlight quantity of transmitted light I _c, it is necessary to reduce the external light reflection factor R. In general, the value of the light amount is I _in > I _c , so it is most effective to reduce the external light reflectance R.

  As other polarizers, absorptive dichroic polarizers are widely used. An absorptive dichroic polarizer can be obtained by stretching a polymer film coated with a compound having absorption anisotropy of light (iodine, dichroic dye). When this absorptive polarizer is used for a display device, the transmittance does not exceed 50% in principle, and there is a problem that the light use efficiency is low. Furthermore, there was also a problem inferior in durability in a high temperature and high humidity environment (Non-patent Document 2).

In response to the above problems, wire grid polarizers (Patent Document 2 and Patent Document 3) using chromium as a wire grid material to reduce reflection of non-transmitted light, and wire grid polarizers provided with a light-absorbing thin film layer (Patent Document 4) is proposed, and further, a polarizer (Patent Document 5 and Patent Document 6) in which a reflective wire grid polarizer and a light-absorbing material are combined is proposed.
Bulletin of Japan Women's University Faculty of Science No. 14 (2006) Optical Materials for FPD Monthly Display October issue separate volume (2007) Techno Times Special table 2003-502708 gazette JP 2004-309903 A Table 2006-066493 JP 2006-330616 A JP-A-2005-37900 JP 2008-46637 A

  However, in the configurations described in Patent Documents 2 and 3, the reflectivity is lower than when aluminum is applied to the wire grid material, but the reflectivity is higher than that of the absorptive dichroic polarizer. It has not yet been solved to suppress the reflection of light. Furthermore, the configuration described in Patent Document 2 has a low degree of polarization and cannot be used practically as a polarizer.

  Further, in the configuration described in Patent Document 4, the reflectivity is lowered, but at the same time, the degree of polarization and the transmittance are also lowered, and there is a problem that there is no practicality as a polarizer. Furthermore, the polarizers described in Patent Documents 2 and 4 have a problem that the light utilization efficiency is lowered.

  Further, as described in Patent Documents 5 and 6, in the configuration in which a light absorbing material is laminated on the wire grid of the reflective wire grid polarizer, a multilayer film such as a dielectric, a low reflective metal, and an oxide is vacuum deposited. However, since it is necessary to process the multilayer film into a wire shape with a pattern of several hundreds of nanometers, there is a problem that it takes time to form and process the multilayer film.

  In addition, since the types of gases that are optimal for dry etching in the microfabrication of metals, dielectrics, and oxides that make up multilayer films into wire shapes differ between the metal phase, oxide layer, and dielectric layer, etching is performed. In wet etching, there is a problem that it is difficult to select an optimal etching solution.

  In addition, as described in Patent Document 5, in a configuration in which a striped grating layer is formed on the front and back surfaces of the base material with a reflective material and an absorptive material, respectively, it is installed at optically parallel positions on the front and back surfaces of the flat substrate. However, as a procedure, a striped grating layer is provided on one side of the flat substrate, and a striped grating layer is provided on the other side plane while maintaining the optical parallel position. However, it is difficult to provide a grating layer on both surfaces of the base material while maintaining parallelism. Here, the optical parallel position means a position where the polarization axes transmitting through the polarizer are parallel to each other.

  Further, by the inventors' investigation, the configuration described in Patent Document 5 can suppress the TE wave reflectivity at the incidence from the absorbent material side, but the TM wave reflectivity is also high, resulting in natural light being observed as a result. It is known that the reflectance cannot be completely suppressed, and that the wavelength dispersion of TM transmittance is large and sufficient color reproducibility cannot be achieved.

  In addition, as a method of using the absorbing polarizer, a method of stacking with a reflective polarizer is proposed. However, the conventionally proposed absorption polarizer has a low transmittance, and when it is laminated with a reflective polarizer to form a composite polarizer, there is a problem in practical use because the polarizer has a low transmittance. Further, when the transmittance is increased, the effect of reflection of the laminated reflective polarizer becomes stronger, and there is a problem that reflection suppression for incident light on the outside light side is insufficient.

  The present invention has been made in view of such a point, and satisfies the performance of both high transmittance and low reflectance, and in a composite polarizer laminated with a reflective wire grid polarizer, the light utilization efficiency on the backlight side is improved. An object of the present invention is to provide an absorptive wire grid polarizer that can enhance and suppress the reflectance with respect to incident light on the outside light side and realize sufficient color reproducibility and black display.

  The absorptive wire grid polarizer of the present invention is a substrate transparent to visible light having convex portions in a lattice shape, and formed on the convex portions of the base material, each of which is composed of at least an absorptive polarizing component. And a two-layer laminate.

  In the absorptive wire grid polarizer of the present invention, the laminate has a thickness of 5 nm or more and 250 nm or less in a state of being offset over a region including a part of the side surface of the lattice-like convex portion of the substrate in a cross-sectional view. Preferably it is formed. In this case, the thickness of the stacked body is preferably 5 nm or more and 30 nm or less.

  In the absorptive wire grid polarizer of the present invention, the absorptive polarization component contains molybdenum, chromium, tungsten, zirconium, tantalum, nickel, iron, niobium, hafnium, cobalt, and at least one of these as a main component. It is preferably at least one low reflection material selected from the group consisting of alloys.

  In the absorptive wire grid polarizer of the present invention, it is preferable that the absorptive polarization component is mainly composed of at least one material selected from the group consisting of aluminum oxide, iron oxide, and nickel oxide.

  The absorptive wire grid polarizer of the present invention is a substrate transparent to visible light having convex portions in a lattice shape, and formed on the convex portions of the base material, each of which is composed of at least an absorptive polarizing component. 2 layers of laminates, satisfying both high transmittance and low reflectance performance, in a composite polarizer laminated with a reflective wire grid polarizer, increasing the light utilization efficiency on the backlight side, The reflectance with respect to the incident light on the outside light side can be suppressed, and sufficient color reproducibility and black display can be realized when arranged in a display device such as an LCD.

  In order to change the optical constant, methods such as alloying of materials, mixing of impurities, and change of crystal structure are taken. It has been found that the constant (n, k) indicates an approximately average value of the optical constant (n, k) of each material constituting the laminate in the light incident surface. This is presumably because the layered portion has an optical constant as if the individual materials were locally alloyed. That is, the present inventors use a laminate of at least two layers each composed of an absorbing polarization component without using conventional techniques such as material alloying, impurity mixing, and crystal structure change. It has been found that the optical constant is changed. This is preferable in terms of optical design of the wire grid polarizer because the optical constant (n, k) of the low reflection material wire portion can be arbitrarily designed.

  Furthermore, the present inventors have no lattice-like convex portions of the base material, and even if a laminated body is provided on a flat base material, regardless of the shape and film thickness of the low reflective material wire, i) high transmittance and Low reflectivity shows contradictory characteristics, and ii) confirms that the wavelength dispersion of the reflectivity is increased, and the above phenomenon is that a laminate is provided on the grid-like convex part of the substrate having the grid-like convex part. Was found for the first time. The present inventors have completed the present invention based on such findings.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic cross-sectional perspective view showing an example of an absorptive wire grid polarizer according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional perspective view showing the absorptive wire grid polarizer 1 of FIG. FIG.

  The absorption wire grid polarizer shown in FIG. 2 is a laminate of at least two layers covering a base 1b having a lattice-like convex portion 1a on the surface and a part of a side portion in a cross-sectional view of the lattice-like convex portion 1a. The reflective material wires 1c and 1d are mainly composed. Here, for simplification of description, a two-layer laminate in which the first layer from the lattice-shaped convex portion 1a side is the low reflection material wire 1c and the second layer is the low reflection material wire 1d will be described. The invention is not limited to this, and the laminate may be composed of three or more layers.

As shown in FIG. 2, the laminated body (reflective material wires 1c and 1d) is formed in a state of being offset over a region including a part of the side surface of the grid-like convex portion 1a of the base material 1b in a cross-sectional view. Here, the offset state, and X ₁ (perpendicular substantially perpendicular to the surface of the substrate 1b in cross-section view) virtual vertical line passing through the top of the grid-shaped convex portions 1a, a virtual perpendicular line passing through the top of the stack It means a state that does not match. In FIG. 2, the reflecting material wire in a state where the virtual perpendicular X ₁ passing through the top of the lattice-shaped convex portion 1 a and the virtual perpendiculars X ₂ and X ₃ passing through the top of the reflecting material wires 1 c and 1 d are not aligned. 1c and 1d are formed on the grid-like convex portion 1a. In the present invention, it is said that such a state is formed in a state of being offset over a region including a part of the side surface of the grid-like convex portion 1a.

  Thus, it is preferable that the low reflection material wires 1c and 1d cover at least a part of the lattice-shaped convex portion 1a in a cross-sectional view. In particular, it is preferable to form the low-reflective material wires 1c and 1d so as to cover only the side surfaces (slope portions) in the cross-sectional view of the grid-like convex portion 1a because predetermined optical performance can be obtained. As shown in FIG. 2, when the low-reflection material wires 1c and 1d are formed so as to cover only one slope portion in a cross-sectional view, it is possible to suppress wavelength dispersion of transmittance and reflectance with high transmittance and low reflectance. Therefore, it is more preferable.

  In addition, the reason why the wavelength dispersion of the optical characteristics can be suppressed with a high transmittance when formed in a state of being offset over a region including a part of the side surface of the grid-like convex portion 1a in the cross sectional view of the convex portion. Although it is unclear, due to the effective medium theory, due to the cross-sectional change between the low reflection material wires 1c and 1d and the lattice-shaped convex portion 1a with respect to the light incident direction, a sharp change in optical characteristics with respect to the light incident direction occurs. This is presumed to be suppressed.

That is, in FIG. 2, when the incident direction of light and the virtual perpendicular line X ₁ and X _2, X ₃ and parallel to the direction, toward the base from the apex of the convex shape of the low reflective alloy wire 1c, 1d and grid-shaped convex portions 1a Since the volume occupancy of the surrounding medium (medium including the space between the lattice-shaped convex portions, for example, air), the low-reflective alloy material wires 1c and 1d and the resin forming the lattice-shaped convex portions 1a gradually changes, the optical constant distribution The amount of change is gentle with respect to the incident direction of light. Since the reflection of light mainly occurs due to a rapid change in the optical constant, it is presumed that the reflection of light is suppressed for a continuous change in the optical constant.

  In addition, the low reflection material wires 1c and 1d are preferably formed of a thin film having a thickness of 5 nm or more and 250 nm or less on one inclined surface in a cross-sectional view of the lattice-like convex portion 1a. It is preferable that the film thickness is in the above-mentioned range since the optimum TE wave and TM wave transmittance can be obtained as an absorption polarizer. More preferably, the thickness of the low reflection material wires 1c and 1d is 5 nm or more and 30 nm or less.

  The thickness of each layer of the low reflection material wires 1c and 1d can be appropriately set according to the desired optical characteristics. The details for determining the thickness of each layer are unknown, but are estimated as follows by the effective medium theory.

If the light incident direction is parallel to the virtual perpendicular lines X _1, X ₂ , and X ₃ , the incident light travels through a region where the optical constant distribution is gentle with respect to the light incident direction, so that reflection is suppressed. However, in order to suppress reflection more effectively, the amount of change in the optical constant at the light incident interface may be made gentler. That is, it is presumed that the reflection can be further suppressed if the low-reflective alloy material wire 1d is made of a relatively low-reflective material and the thickness of the portion above the apex of the low-reflective alloy material wire 1c is increased. The Further, in order to increase the TE wave absorption rate, it is preferable to use a material having a large optical constant for the low-reflective alloy material wire 1c, and it is better that the thickness is thicker. Are in a trade-off relationship. Furthermore, it has been found that the portions where the low-reflective alloy material wires 1c and 1d and the lattice-shaped convex portions 1a overlap each other have an optical constant approximately equal to an approximation based on the effective medium theory. As described above, the optical characteristics can be adjusted in accordance with the effective medium theory by the material and thickness of each layer of the individual low reflection material wires 1c and 1d, so that the optical design of the wire grid polarizer is facilitated.

  As the material constituting the low reflection material wires 1c and 1d in FIG. 2, at least one low reflection material selected from the group consisting of molybdenum, chromium, tungsten, zirconium, tantalum, nickel, iron, niobium, hafnium, cobalt, Alternatively, a low reflection material such as an alloy mainly composed of at least one material selected from this group can be used.

  Further, the material constituting the low reflection material wires 1c and 1d is at least one low reflection material selected from the group consisting of vanadium, germanium, iridium, osmium, titanium and manganese, or at least one selected from this group. A low reflection material such as an alloy containing one material as a main component may be used.

  The material constituting the low-reflection material wires 1c and 1d is preferably mainly composed of at least one material selected from the group consisting of aluminum oxide, iron oxide, and nickel oxide, and magnesium, silicon, Titanium, vanadium, chromium, manganese, cobalt, copper, zinc, gallium, yttrium, zirconium, niobium, molybdenum, ruthenium, rhodium, indium, tin, antimony, tellurium, hafnium, tantalum, tungsten, iridium, thallium, bismuth A material mainly composed of an oxide of at least one element selected from the above may be used. An oxide exhibiting transparency with a stoichiometric composition is preferable because absorption efficiency is increased by making it non-stoichiometric, that is, a non-completely oxidized state. These oxides may be used alone or as a mixture.

  Since the low reflection material wires 1c and 1d are thin films, the reflectance and transmittance of the TE wave can be suppressed low and the absorption rate can be increased even though they are wire grid polarizers. The details that the TE wave absorption rate becomes high with a thin low-reflection material wire are not clear, but it is presumed that the absorption inside the low-reflection material increases because it is the same as the penetration length of the low-reflection material.

  Further, from the viewpoint of protecting the low reflection material wire 1c, a thin film of a transparent dielectric layer (not shown) may be provided on the low reflection material wire 1c. The method for forming the dielectric layer on the low reflection material wire 1c is appropriately selected depending on the material constituting the dielectric layer. For example, a physical vapor deposition method such as a sputtering method or a vacuum vapor deposition method can be suitably used.

  The material used for the substrate 1b may be a material that is substantially transparent in the visible light region, but is preferably a resin excellent in workability. 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 (PET) resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal Examples include crystalline thermoplastic resins such as resins and polyamide resins, and ultraviolet (UV) curable resins and thermosetting resins such as acrylic, epoxy, and urethane types. That. Moreover, you may use the composite base material which combined the ultraviolet curable resin and the thermosetting resin, inorganic substrates, such as glass, the said thermoplastic resin, and a triacetate resin as the base material 1b.

  The pitch of the grid-shaped convex portions 1a on the substrate 1b is 150 nm or less, preferably 80 nm to 120 nm in consideration of polarization characteristics over a wide band in the visible light region. The smaller the pitch, the better the polarization characteristics. However, for visible light, sufficient polarization characteristics can be obtained at a pitch of 80 nm to 120 nm. When the polarization characteristics of short wavelength light in the vicinity of 400 nm are not important, the pitch may be increased to about 150 nm.

  In the present invention, the pitch of the grid-like convex portions 1a on the substrate 1b and the pitch of the low reflection material wires 1c and 1d are substantially equal and can be the same pitch.

  There is no restriction | limiting in the cross-sectional shape of the grid-like convex part 1a on the base material 1b. Examples of the cross-sectional shape include a trapezoidal shape, a rectangular shape, a square shape, a prism shape, and a sine wave shape such as a semicircular shape. Here, the sinusoidal shape means having 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. In addition, from the viewpoint of easily covering the lattice-shaped convex portion 1a on the substrate 1b and at least a part of its side surface with the low-reflective material, the end portion, the top portion, or the valley portion of the shape is curved with a gentle curvature. Is preferred. Further, from the viewpoint of increasing the adhesion strength between the base material 1b, the lattice-like convex portion 1a, and the low reflection material wires 1c and 1d, it is more preferable that these cross-sectional shapes are sinusoidal. Furthermore, a thin film of a transparent dielectric layer (not shown) may be provided in the same manner from the viewpoint of increasing the adhesion strength between the base material 1b, the lattice-like convex portion 1a, and the low reflection material wires 1c and 1d.

  As a method of providing the grid-like convex portions 1a on the substrate 1b, a method of using a mold having a grid-like convex portion having a pitch of 150 nm or less on the surface and transferring and molding the grid-like convex portions on the surface of the equipment. It is done. Here, the mold having a grid-like convex part with a pitch of 150 nm or less on the surface is made conductive in order by applying a resist pattern having a grid-like convex part with a pitch of 150 nm or less, obtained by electron beam lithography or interference exposure. It can be produced by performing a treatment, a plating treatment, and a substrate removal treatment.

  As a method of forming the low reflection material on the base material 1b and the lattice-like convex portion 1a in order to form the low reflection material wires 1c and 1d, sufficient adhesion can be obtained between the low reflection material and the base material. 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. A method in which selective lamination can be performed while being biased toward one slope portion of the grid-like convex portion is preferable, and an oblique deposition method or the like can be given. Further, when the oxide material is the low-reflection material wire 1c, the optical constant (n, k) can be arbitrarily changed by the reactive sputtering method, so that the optical design of the absorption wire grid polarizer in the present invention is achieved. In addition, the sputtering method is preferable.

  In the absorptive wire grid polarizer 1 according to the present invention, in TE waves, the transmittance is preferably 50% or less and the reflectance is 40% or less, the transmittance is 40% or less, and the reflectance. Is more preferably 20% or less. In the TM wave, the transmittance is preferably 80% or more and the reflectance is 10% or less, more preferably the transmittance is 85% or more and the reflectance is 8% or less. The transmittance and reflectance of TE waves and TM waves are measured using a spectrophotometer.

  The absorptive wire grid polarizer of the present invention satisfies both high transmittance and low reflectivity, and has a high degree of polarization. Therefore, the absorptive wire grid polarizer functions as a polarizer by itself. When integrated in a display device such as a liquid crystal display device, the reflection of the external light side is improved in the state where the light use efficiency of the backlight, which is a characteristic of the reflective wire grid polarizer, is increased. It can be suppressed and is preferable.

  FIG. 3 is a schematic cross-sectional perspective view showing an example of application of the absorption type wire grid polarizer according to the embodiment of the present invention. The absorptive wire grid polarizer 1 is laminated and integrated with a reflective wire grid polarizer 2 to form a composite wire grid polarizer 3.

  Since the TM transmittance is high, the transmittance of the composite wire grid polarizer 3 laminated and integrated on the reflective wire grid 2 does not decrease. Further, the reflected light of the external light 4 will be described in detail with reference to FIG.

  FIG. 4 is a schematic cross-sectional view of a composite wire grid polarizer in which an absorption wire grid polarizer and a reflection wire grid polarizer are laminated and integrated, and the low reflection material wires 1c and 1d of the absorption wire grid polarizer and reflection. The reflective metal wire 2a of the type wire grid polarizer, the transparent substrate of both wires, and the adhesive layer are schematically shown as a transparent substrate layer 6.

The TE wave of the external light 4 is partially reflected by the low reflection material wires 1c and 1d and partially transmitted. The transmitted light is partially reflected by the reflective metal wire 2a and returns to the low reflection material wires 1c and 1d again, so that the reflected light and the transmitted light are separated. The sum of the multiple reflections is recognized as reflected light 4R and is approximated by the following equation.
4R = R1c + (T1c) ² * R2a / (1-R1c * R2a) 1)
here,
R1c: reflectance of the low reflection material wires 1c, 1d T1c: transmittance of the low reflection material wires 1c, 1d R2a: reflectance of the reflective metal wire 2a

  Since the reflectivity of the reflective wire metal 2a is high, the reflectivity of the TE wave of the external light 4 is greatly affected by the square of the reflectivity R1c and the transmissivity Ta of the low reflection material wires 1c and 1d based on the above formula 1). It can be seen that the transmittance T1c need not be as low as the reflectance R1c.

  The above is about the reflection of the TE wave, but the same formula is applied to the TM wave, but since R2a is small, the transmittance T1c does not need to be suppressed as much as the TE wave.

  The absorptive wire grid polarizer and the reflective wire grid polarizer are bonded at an optically parallel position to obtain a polarizer 3 shown in FIG. Examples of the reflective wire grid polarizer to be bonded include a reflective wire grid polarizer composed of at least a base material and a metal wire grid disposed on the base material. The base material constituting the reflective wire grid is not particularly limited as long as it is a material that is substantially transparent in the visible light region, and examples thereof include glass, transparent inorganic crystals, and transparent plastic. Examples of the glass include quartz glass and existing optical glasses such as BK (borosilicate crown), BaK (barium crown), LF (light flint), and SF (heavy flint). Of these, quartz glass is preferable because it is suitable for surface fine processing. Examples of the transparent inorganic crystal include sapphire, crystal, calcite, and alkali halide. Examples of the transparent plastic include 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, polyether. Amorphous thermoplastic resins such as imide resin, polyether sulfone resin, polysulfone resin, polyether ketone resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic Crystalline thermoplastic resins such as aromatic polyester resins, polyacetal resins, and polyamide resins, and ultraviolet (UV) curing such as acrylic, epoxy, and urethane types It includes fat or thermosetting resin.

  The substrate surface does not have to be flat, and irregularities of about 100 nm may be formed.

  The material used for the metal wire grid is preferably a material having high light reflectance in the visible light region and good adhesion to the substrate. For example, it is preferably made of aluminum, silver, tin, or an alloy thereof. From the viewpoint of cost, it is more preferable that it is made of Al or an Al alloy.

  The shape of the metal wire grid and the cross-sectional shape of the metal wire grid are not particularly limited as long as sufficient polarization characteristics can be maintained in the visible light region, and are sinusoidal such as rectangular, trapezoidal, rectangular, prismatic, and semicircular. Furthermore, the shape etc. which combined these are mentioned. The pitch is 150 nm or less, preferably 80 nm to 120 nm in consideration of polarization characteristics in a wide band in the visible light region.

  As a method of forming a metal wire grid on the substrate surface, various known methods can be mentioned. For example, an interference exposure method using an extreme ultraviolet laser, a method using electron beam lithography, or a method of projecting at a desired pitch in advance. And a method of forming a metal wire on a substrate provided with a lattice.

  Examples of a method of laminating the absorption type wire grid polarizer and the reflection type wire grid polarizer at an optically parallel position include the following methods.

  In FIG. 5, the linearly polarized light that has been transmitted through the existing polarizer 12 is transmitted through the absorptive wire grid polarizer 11. The absorptive wire grid polarizer 11 is rotated around the optical axis of the transmitted light 10 so that the amount of transmitted light 10 is minimized. The side 11a of the absorptive wire grid polarizer 11 is cut in accordance with a base to which a polarizer 12 (not shown) is fixed. By such an operation, the side 11 a becomes parallel to the polarization axis of the polarizer 12. Similarly, for the reflective polarizer, a side parallel to the polarization axis of the polarizer 12 is obtained. Next, by laminating these sides mechanically, a polarizer in which an absorption polarizer and a reflection polarizer are integrated at an optical parallel position is obtained.

  The direction of lamination may be such that each of the reflection type and absorption type wire grids is 180 degrees opposite to the incident light. As shown in FIG. 6, the low reflection material wires 1c of the absorption type wire grid polarizer 1 are arranged. 1d may be laminated on the back surface of the reflective wire grid polarizer 2 with an adhesive layer 7 interposed therebetween, or an absorption type and a reflective type wire grid (not shown) may be laminated at opposite positions. When the wire grid is a laminated surface, the optical characteristics change when the adhesive layer is filled between the wires of the wire grid, and therefore, it is preferable that the adhesive layer is in contact with only the top of the wire.

  As described above, in order to obtain a wire grid polarizer in which the wire grid polarizers are arranged in a simple optical parallel position, it can be manufactured at low cost with a simple apparatus. Further, since each polarizer is independent until it is bonded, an optimum and easy manufacturing method can be selected for each polarizer, and there is a great advantage in actual industrial production in view of production efficiency and cost.

  In the absorption type wire grid polarizer of the present invention, since it is an inorganic substance that has a polarization function, it has excellent durability against heat and light.

  Next, the case where the absorption type wire grid polarizer according to the present invention is used in a liquid crystal display device will be described.

  FIG. 7 is a schematic cross-sectional view showing a liquid crystal display device using a composite wire grid polarizer composed of an absorption wire grid polarizer and a reflective wire grid polarizer according to an embodiment of the present invention.

  The liquid crystal display device shown in FIG. 7 is mainly composed of a lighting device 20 such as a backlight that emits light and a liquid crystal panel 23 sandwiched between composite wire grid polarizers 21 and 22 disposed on the lighting device. The The composite wire grid polarizers 21 and 22 are arranged with the reflective wire grid polarizers 21a and 22a facing the backlight side, and the absorption wire grid polarizers 21b and 22b of the present invention are positioned on the opposite side. The liquid crystal panel 23 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. 7, description of various optical elements such as a polarizer protective film, a retardation film, a diffusion plate, an alignment film, a transparent electrode, and a color filter that are normally used is omitted.

  In the liquid crystal display device having such a configuration, the light emitted from the illuminating device 20 enters from the reflective wire grid polarizer 21a of the composite wire grid polarizer 21, passes through the liquid crystal cell 23, and again returns to the composite wire. The light is incident from the reflective wire grid polarizer 22a of the grid polarizer 22 and emitted to the outside (30 in the figure). In this case, since the composite wire grid polarizers 21 and 22 exhibit an excellent degree of polarization in the visible light region, it is possible to obtain a display with high contrast. In addition, incident light from the illumination device 20 that does not transmit is reflected toward the illumination device side and reused to obtain high luminance.

  On the other hand, external light is incident on the composite wire grid polarizer 22 from the absorption wire grid polarizer 22 b of the present invention, passes through the liquid crystal cell 23, and again the absorption wire grid polarizer 21 of the composite wire grid polarizer 21. It is incident from 21b and emitted to the illumination device 20 (31 in the figure). In this case, external light that does not pass through is efficiently absorbed by the absorption type wire grid polarizers 22a and 22b of the present invention. In summary, sufficient color reproducibility and black display can be realized in a liquid crystal display device.

  Next, examples performed to clarify the effects of the present invention will be described. In addition, the dimension, material, etc. in the following embodiment are illustrative and can be implemented with appropriate changes. Other modifications can be made without departing from the scope of the present invention.

[Example 1]
(Preparation of a substrate having a grid-like convex part)
-Production of fine concavo-convex lattice shape A fine concavo-convex lattice was formed on a substrate coated with a photoresist on glass by using an electron beam drawing method. When the surface and cross section of this resist pattern were observed with a field emission scanning electron microscope (STEM, Hitachi High-Technologies S-5500), the pitch and height of the fine concavo-convex grating were 145 nm / 130 nm (pitch / height), respectively. It was found that the cross-sectional shape was substantially trapezoidal, the shape from the top surface was a striped lattice, the width of the convex portion was 45 nm, and the width of the valley portion was 70 nm.

-Nickel stamper production The surface of the obtained resist pattern with a pitch of 145 nm was coated with 30 nm of gold as a conductive treatment by sputtering, then electroplated with nickel, and a nickel stamper having a fine concavo-convex grating with a thickness of 0.3 mm on the surface Was made.

・ Preparation of lattice-shaped convex transfer film using UV curable resin About 0.03 mm UV curable resin (PAK01 manufactured by Toyo Gosei Co., Ltd.) was applied to 0.1 mm thick polyethylene terephthalate resin film (hereinafter referred to as PET film) Then, on the nickel stamper having the fine concavo-convex grating with 145 nm pitch on the surface with the coating surface facing down, it is placed so that air does not enter between the nickel stamper and the PET film from each end, and the center from the PET film side. Ultraviolet rays were irradiated at 1000 mJ / cm ² using an ultraviolet lamp having a wavelength of 365 nm to transfer the fine uneven grating of the nickel stamper. The obtained lattice-like convex transfer film was observed by STEM, and it was confirmed that the cross-sectional shape was substantially trapezoidal and the shape from the upper surface was a striped lattice.

-Production of absorption polarizer A lattice-shaped convex transfer film produced using the above-described ultraviolet curable resin was coated with a dielectric using a sputtering method. In this embodiment, a case where silicon nitride is used as a dielectric will be described. The dielectric was coated at an Ar gas pressure of 0.67 Pa, a sputtering power of 4 W / cm ² , and a coating speed of 0.22 nm / second. As a layer thickness comparison sample, a glass substrate having a smooth surface was inserted into the apparatus simultaneously with the lattice-shaped convex transfer film, and film formation was carried out so that the dielectric laminate thickness on the smooth glass substrate was 5 nm.

A dielectric layer was formed on the lattice-shaped convex transfer film, and then a tantalum / nickel tungsten alloy laminate wire was formed by sputtering. In this example, first, using a nickel tungsten alloy (nickel 81 wt%, tungsten 19 wt%), the argon gas pressure was 0.16 Pa (purity 99.999%), the target applied power density was 4.4 W / cm ² , Vapor deposition was performed at a film forming rate of 51.5 nm / min. The distance between the nickel-tungsten alloy and the grid-like convex transfer film is 105 mm. As a layer thickness comparison sample, a glass substrate having a smooth surface was inserted into the apparatus simultaneously with the dielectric laminated lattice-shaped convex transfer film, and vapor deposition was performed so that the nickel tungsten deposition thickness on the smooth substrate was 10.3 nm. The angle formed by the normal of the substrate surface and the vapor deposition source in a plane perpendicular to the vertical direction of the lattice was 50 degrees.

Further, on the nickel tungsten alloy layer, sputtering is performed using tantalum with an argon gas pressure of 0.16 Pa (purity 99.999%), a target applied power density of 4.4 W / cm ² , and a film formation rate of 33 nm / min. To form a film. The distance between the tantalum and the lattice-shaped convex transfer film is 105 mm. As a layer thickness comparison sample, a glass substrate having a smooth surface was inserted into the apparatus at the same time as the dielectric laminated lattice-shaped convex transfer film, and vapor deposition was performed so that the tantalum deposition thickness on the smooth substrate was 12.1 nm. The angle formed by the normal of the substrate surface and the vapor deposition source in a plane perpendicular to the vertical direction of the lattice was 50 degrees.

  When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the tantalum / nickel tungsten alloy laminated wire was formed with a thickness of about 22 nm on one side of the cross-sectional slope of the lattice-like convex portion. It was.

  About the obtained absorption type wire grid type polarizer, the transmitted light intensity and reflected light intensity in parallel Nicol and orthogonal Nicol with respect to linearly polarized light were measured using a spectrophotometer. As a result, the absorption wave grid polarizer has a TM wave transmittance of 87.5%, a TE wave transmittance of 18.7%, a TM wave reflectance of 4.2%, a TE wave reflectance of 17.6%, and a polarization degree of 84. 8%.

[Example 2]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, a tantalum wire is formed to a thickness of 12.1 nm using a sputtering method, and a tungsten wire is further formed on the tantalum layer. The film was laminated to a film thickness of 9.5 nm to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the tungsten / tantalum laminated wire was formed with a thickness of about 21 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. The absorption wire grid polarizer thus obtained had a TM wave transmittance of 89.3%, a TE wave transmittance of 15.3%, a TM wave reflectance of 4.4%, a TE wave reflectance of 20.7%, and a polarization degree of 70. 0.7%.

[Example 3]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, a tungsten wire is formed to a thickness of 9.5 nm by sputtering, and a nickel tungsten alloy is further formed on the tungsten layer. Wires (81 wt% nickel, 19 wt% tungsten) were laminated to a film thickness of 10.3 nm to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the nickel tungsten alloy / tungsten laminated wire was formed with a thickness of about 20 nm on one side of the cross-sectional slope of the lattice-like convex portion. It was. The absorption wire grid polarizer thus obtained has a TM wave transmittance of 87.9%, a TE wave transmittance of 16.3%, a TM wave reflectance of 4.1%, a TE wave reflectance of 20.6%, and a polarization degree of 68. 0.7%.

[Example 4]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, a zirconium wire was formed to a thickness of 11.7 nm by sputtering, and a molybdenum wire was further formed on the zirconium layer. The film was laminated to a film thickness of 11.8 nm to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the molybdenum / zirconium laminated wire was formed with a thickness of about 22 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. The absorption wire grid polarizer thus obtained had a TM wave transmittance of 89.2%, a TE wave transmittance of 18.9%, a TM wave reflectance of 3.9%, a TE wave reflectance of 19.1%, and a degree of polarization of 65. 0.0%.

[Example 5]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, a chromium wire is formed to a thickness of 9.3 nm by sputtering, and a zirconium wire is further formed on the chromium layer. The film was laminated to a thickness of 12.4 nm to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that a zirconium / chromium laminated wire was formed with a thickness of about 22 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. The absorption wire grid polarizer thus obtained has a TM wave transmittance of 88.8%, a TE wave transmittance of 16.2%, a TM wave reflectance of 4.1%, a TE wave reflectance of 17.4%, and a polarization degree of 69. It was 1%.

[Example 6]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, using a sputtering method, a zirconium wire is formed to a thickness of 12.4 nm, and a chromium wire is further formed on the zirconium layer. The film was laminated to a film thickness of 9.3 nm to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the chromium / zirconium laminated wire was formed with a thickness of about 22 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. The obtained absorption wire grid polarizer has a TM wave transmittance of 89.7%, a TE wave transmittance of 17.7%, a TM wave reflectance of 3.7%, a TE wave reflectance of 18.4%, and a polarization degree of 67. 0.0%.

[Example 7]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, a hafnium wire is formed to a thickness of 10.2 nm by sputtering, and a niobium wire is formed on the hafnium layer. The layers were laminated to a thickness of 10.2 nm to obtain an absorption type wire grid polarizer. When the obtained absorption wire grid type polarizer was observed by STEM, it was confirmed that the niobium / hafnium laminated wire was formed with a thickness of about 20 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. The absorption wire grid polarizer thus obtained has a TM wave transmittance of 88.4%, a TE wave transmittance of 22.1%, a TM wave reflectance of 3.9%, a TE wave reflectance of 12.7%, and a degree of polarization of 60. 0.0%.

[Example 8]
In the same manner as in Example 1, after forming a dielectric on the lattice-shaped convex transfer film, a stainless steel SUS304 was formed to a thickness of 14.7 nm by sputtering, and further on the stainless steel SUS304 layer, oxygen An iron oxide wire was laminated so as to have a film thickness of 14.6 nm by using a reactive sputtering method to obtain an absorption type wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that an iron oxide / stainless steel SUS304 laminated wire was formed with a thickness of about 28 nm on one side of the cross-sectional slope of the lattice-like convex portion. It was. The absorption wire grid polarizer thus obtained had a TM wave transmittance of 91.7%, a TE wave transmittance of 46.5%, a TM wave reflectance of 4.5%, a TE wave reflectance of 5.9%, and a degree of polarization of 32. 0.7%.

[Example 9]
In the same manner as in Example 1, after forming a dielectric on the lattice-like convex transfer film, nickel oxide was formed to a thickness of 20.0 nm using an oxygen reactive sputtering method, and further on the nickel oxide layer. Further, an iron oxide wire was laminated so as to have a film thickness of 14.6 nm using an oxygen reactive sputtering method to obtain an absorption type wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the iron oxide / nickel oxide laminated wire was formed with a thickness of about 24 nm on one side of the cross-sectional slope of the lattice-like convex portion. It was. The absorption wire grid polarizer thus obtained has a TM wave transmittance of 88.8%, a TE wave transmittance of 32.2%, a TM wave reflectance of 3.9%, a TE wave reflectance of 8.9%, and a degree of polarization of 46. 8%.

[Example 10]
After forming a dielectric on the lattice-shaped convex transfer film in the same manner as in Example 1, using a sputtering method, nickel was formed to a thickness of 15.0 nm, and the oxygen reactivity was further formed on the nickel layer. An aluminum oxide wire was laminated so as to have a film thickness of 9.5 nm using a sputtering method to obtain an absorption wire grid polarizer. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that the aluminum oxide / nickel laminated wire was formed with a thickness of about 24 nm on one side of the cross-sectional slope portion of the lattice-like convex portion. . The absorption wire grid polarizer thus obtained has a TM wave transmittance of 86.0%, a TE wave transmittance of 30.8%, a TM wave reflectance of 3.8%, a TE wave reflectance of 11.9%, and a polarization degree of 47. 3%.

[Example 11]
After forming a dielectric on the lattice-shaped convex transfer film as in Example 1, using a sputtering method, cobalt is formed to a thickness of 10.0 nm, and on the cobalt layer, sputtering is performed. The nickel wire is laminated so as to have a film thickness of 6.0 nm, and the cobalt wire is laminated on the nickel layer so as to have a film thickness of 10.0 nm using a sputtering method. I got a child. When the obtained absorption wire grid polarizer was observed by STEM, it was confirmed that a cobalt / nickel / cobalt laminated wire was formed with a thickness of about 25 nm on one side of the cross-sectional slope of the lattice-like convex portion. It was. The absorption wire grid polarizer thus obtained had a TM wave transmittance of 84.7%, a TE wave transmittance of 15.6%, a TM wave reflectance of 3.0%, a TE wave reflectance of 27.8%, and a polarization degree of 68. 9%.

  Thus, for the absorption wire grid polarizers of Examples 1 to 11, a material wire as a layer composed of an absorption polarization component is placed on one side of the cross-sectional slope of the lattice-shaped convex part. Since it was provided with a thickness, low reflectance and high transmittance could be realized.

[Example 12]
-Production of Reflective Polarizer A metal wire was formed on a lattice-shaped convex transfer film having silicon nitride formed on the surface in the same manner as described above, using an electron beam vacuum deposition method (EB deposition method). In this example, aluminum was used as the metal. Deposition was performed with a degree of vacuum of 2.5 × 10 ⁻³ Pa, a deposition rate of 20 nm / s, and a substrate temperature of room temperature. As a layer thickness comparison sample, a glass substrate having a smooth surface was inserted into the apparatus at the same time as the dielectric laminated grid-shaped convex transfer film, and vapor deposition was performed so that the aluminum deposition thickness on the smooth substrate was 170 nm. Note that the angle formed by the normal of the substrate surface and the evaporation source in a plane perpendicular to the longitudinal direction of the lattice was 20 degrees.

  After laminating a dielectric and aluminum on the lattice-shaped convex transfer film, the film is placed in a 0.1% by weight sodium hydroxide aqueous solution at room temperature while changing the treatment time at intervals of 10 seconds between 30 seconds and 120 seconds. Cleaning (etching) was performed, and the etching was stopped immediately by washing with water. Thereafter, the film was dried to obtain a reflective wire grid polarizer. From the following polarization performance evaluation, a reflective wire grid polarizer etched for 90 seconds was selected.

  About the obtained reflection type wire grid polarizer, the transmitted light intensity and reflected light intensity in parallel Nicol and orthogonal Nicol with respect to linearly polarized light were measured using a spectrophotometer. As a result, the TM wave transmittance of the reflective wire grid polarizer is 88.7%, the TE wave transmittance is 0.04%, the TM wave reflectance is 3.4%, the TE wave reflectance is 84.8%, and the degree of polarization is 99. 91%.

Stacking of absorption type and reflection type polarizers About one side of the four sides around the reflection type wire grid polarizer obtained by the above-described method and the absorption type wire grid polarizer of Example 1, with reference to the existing polarizer The polarization axis was adjusted. Subsequently, the substrate sides of each wire grid were bonded and bonded together using an optically transparent adhesive material while mechanically aligning one side of the polarization axis.

  About the obtained polarizer, the transmitted light intensity with respect to linearly polarized light and the reflected light intensity were measured using the spectrophotometer. TM wave transmittance 76.05%, TE wave transmittance 0.008%, TM wave reflectance 4.3% on the absorption wire grid polarizer side, TE wave reflectance 21.1%, Total light reflectance 12. 7%. On the reflective wire grid polarizer side, the TM wave reflectance was 4.9%, the TE wave reflectance was 79.6%, the total light reflectance was 42.3%, and the degree of polarization was 99.98%.

  Moreover, the difference from the average value of the transmittance and reflectance at wavelengths from 450 nm to 750 nm is within 5.1% transmittance and within 3.2% reflectance, and has substantially uniform transmission / reflection characteristics in this range. I understand. Further, by laminating, the total light reflectance of the reflective wire grid polarizer can be reduced from 44.1% to 12.7% after laminating, and the performance is sufficient for sufficient black display. It was confirmed that there was.

  As described above, the absorptive wire grid polarizer according to the present invention satisfies both the high transmittance and the low reflectance, and in the composite polarizer laminated with the reflective wire grid polarizer, the light utilization efficiency on the backlight side. And the reflectance with respect to the incident light on the outside light side is suppressed, and sufficient color reproducibility and black display can be realized when disposed in a display device such as an LCD. Furthermore, since the expression of the polarization function is entirely composed of an inorganic material, the durability is excellent.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, the dimensions, materials, and the like in the above-described embodiment are illustrative, and can be changed as appropriate. Moreover, the polarizing plate in the said embodiment does not need to be a plate-shaped member, and may be a sheet form and a film form as needed. In the above embodiment, the case where the wire grid polarizing plate is applied to a liquid crystal display device has been described. However, the present invention can be similarly applied to devices other than the liquid crystal display device that requires polarized light. . In addition, various modifications can be made without departing from the scope of the present invention.

It is a schematic sectional perspective view which shows an example of the absorption type wire grid polarizer which concerns on embodiment of this invention. FIG. 2 is a schematic cross-sectional perspective view illustrating the absorption wire grid polarizer illustrated in FIG. 1 in an enlarged manner. 1 is a schematic cross-sectional perspective view of a polarizer in which an absorption wire grid polarizer and a reflection wire grid polarizer according to an embodiment of the present invention are laminated and integrated. FIG. 5 is a schematic cross-sectional view showing the behavior of reflected light in an absorption wire grid polarizer and a polarizer in which an absorption wire grid polarizer is laminated and integrated. It is the schematic which shows an example of the adhesion | attachment process for adhere | attaching the absorption type wire grid polarizer of this invention, and a reflection type wire grid polarizer. It is a schematic sectional perspective view which shows an example of the other structure which laminates | stacks the absorption type wire grid polarizer of this invention, and a reflection type wire grid polarizer. It is a cross-sectional schematic diagram which shows the liquid crystal display device using the absorption type wire grid polarizer which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11,21b, 22b Absorption type wire grid polarizer 1a Lattice-like convex part 1b Base material 1c, 1d Low reflection material wire 2, 21c, 22a Reflection type wire grid polarizer 2a Reflection type metal wire 3 Composite type wire grid polarization Child 4,5 Incident light 6 Transparent substrate layer 7 Adhesive layer 10 Transmitted light 11a Side coincident with change axis 12 Polarizer 20 Illumination device 21, 22 Wire grid polarizer 23 Liquid crystal panel 30 Backlight incident light 31 External light incident light

Claims (5)

  A substrate transparent to visible light having convex portions in a lattice shape, and a laminate of at least two layers formed on the convex portions of the substrate and each composed of an absorption-type polarization component; Absorptive wire grid polarizer.   The laminated body is formed with a thickness of 5 nm or more and 250 nm or less in a state where the laminated body is inclined over a region including a part of a side surface of the lattice-like convex portion of the base material in a cross-sectional view. The absorption type wire grid polarizer described in 1.   The absorptive wire grid polarizer according to claim 2, wherein the thickness of the laminate is 5 nm or more and 30 nm or less.   The absorptive polarizing component is at least one low selected from the group consisting of molybdenum, chromium, tungsten, zirconium, tantalum, nickel, iron, niobium, hafnium, cobalt, and an alloy containing at least one of them as a main component. The absorptive wire grid polarizer according to any one of claims 1 to 3, wherein the absorptive wire grid polarizer is a reflective material.   The absorption according to any one of claims 1 to 3, wherein the absorptive polarization component is mainly composed of at least one material selected from the group consisting of aluminum oxide, iron oxide, and nickel oxide. Wire grid polarizer.

Images