JP5139830B2 - Wire grid type polarizing element - Google Patents

Description

  The present invention relates to a wire grid type polarizing element.

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

  For example, a wire grid in which conductor wires made of metal or the like are arranged in a lattice pattern at a specific pitch has a pitch that is considerably smaller than 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. It can be used as a polarizing plate that produces a single polarized light. The wire grid type polarizing element is desirable from the viewpoint of effective use of light because it can reflect and reuse light that does not pass through.

An example of such a wire grid type polarizing element is disclosed in Patent Document 1. The wire grid polarizer includes light reflecting material wires spaced at a grid period smaller than the wavelength of incident light.
JP 2002-328234 A

  However, in the configuration disclosed in Patent Document 1, the light reflecting material wire reflects not only the light from the backlight side but also the light from the outside light side, so that the wire grid polarizer is like a liquid crystal display device. When it is provided in a display device, there is a problem that sufficient color reproducibility and black display cannot be performed.

  The present invention has been made in view of the above points, and provides a wire grid type polarizing element capable of realizing sufficient color reproducibility and black display when disposed in a display device such as a liquid crystal display device. Objective.

The wire grid type polarizing element of the present invention includes: a base material; a light reflecting material wire formed in a lattice shape on the base material at a predetermined interval; and the light reflecting material wire and the light reflecting material wire. an intermediate layer formed between the grid, through said intermediate layer is formed on the light reflective material on the wire, comprising a semi-transparent layer that transmits part of the light therein, wherein the substrate, 80 nm Lattice-like convex portions are arranged in parallel at intervals of ˜150 nm, the intermediate layer formed on the light reflecting material wire and the intermediate layer formed between the light reflecting material wire lattices are continuous, The reflected light of the light incident from the semi-transmissive layer side is attenuated.

The wire grid type polarizing element of the present invention includes a base material, a semi-transmissive layer formed on the base material at a predetermined interval in a lattice shape and transmitting a part of light to the inside, and the semi-transmissive layer And an intermediate layer formed between the lattices of the light transmission layer, and a light reflecting material wire formed on the light transmission layer via the intermediate layer , and the substrate has a thickness of 80 nm to 150 nm. Lattice-like convex portions are juxtaposed at intervals, and the intermediate layer formed on the semi-transmissive layer and the intermediate layer formed between the lattices of the semi-transmissive layer are continuous, from the base material side The reflected light of the incident light is attenuated.

In the wire grid type polarizing element of the present invention, a film shape is preferable.

  In the wire grid type polarizing element of the present invention, the semi-transmissive layer includes Ti, Hf, V, Nb, Ta, Cr, Mo, W, Co, Rh, Ir, Ni, Pd, Pt, Cu, Al, Si. And at least one selected from the group consisting of Ge and Ge, or a compound of these elements.

  In the wire grid type polarizing element of the present invention, the intermediate layer preferably contains a material selected from the group consisting of magnesium fluoride, silicon oxide, aluminum oxide, titanium oxide, zinc oxide, zinc sulfide and aluminum nitride. .

In the wire grid type polarizing element of the present invention, the refractive index and extinction coefficient of the intermediate layer are n ₁ and k ₁ , respectively, and the refractive index and extinction coefficient of the semi-transmissive layer are n ₂ and k ₂ , respectively. Sometimes it is preferable to satisfy k ₂ > k ₁ , n ₂ > 0.5, and k ₂ > 0.5.

  In the wire grid type polarizing element of the present invention, it is preferable that the semi-transmissive layer is formed from a predetermined angle with respect to a standing direction of the light reflecting material wire in a cross sectional view.

  The display device of the present invention includes a display device, illumination means for illuminating the display device, and the wire grid type polarizing element, and the wire grid type polarizer has the light reflecting material wire side on the illumination means. It is arranged on the side.

The wire grid type polarizing element of the present invention includes: a base material; a light reflecting material wire formed in a lattice shape on the base material at a predetermined interval; and the light reflecting material wire and the light reflecting material wire. an intermediate layer formed between the grid, through said intermediate layer is formed on the light reflective material on the wire, comprising a semi-transparent layer that transmits part of the light therein, wherein the substrate, 80 nm Lattice-like convex portions are arranged in parallel at intervals of ˜150 nm, the intermediate layer formed on the light reflecting material wire and the intermediate layer formed between the light reflecting material wire lattices are continuous, Since the reflected light of the light incident from the semi-transmissive layer side is attenuated, sufficient color reproducibility and black display can be realized when it is disposed in a display device such as a liquid crystal display device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic view showing a part of a wire grid type polarizing element according to an embodiment of the present invention. A wire grid type polarizing element shown in FIG. 1 includes a base material 1 in which grid-like convex portions 1a are arranged in parallel at predetermined intervals, an intermediate layer 3 formed on a light reflecting material wire 2, and an intermediate layer 3 And a semi-transparent layer 4 that transmits a part of the light to the inside. In addition, the light reflection material wire 2 provided on the grid | lattice-like convex part 1a may be provided only in the upper part of the grid | lattice-like convex part 1a. When this wire grid type polarizing element is mounted on a display device having an illumination means such as a backlight, the transflective layer 4 is positioned on the outside light side, and the substrate 1 is positioned on the backlight side. Arranged. As a result, the light A from the backlight side is reflected by the light reflecting material wire 2 and the external light B is partially transmitted through the semi-transmissive layer 4 so that the semi-transmissive layer 4, the intermediate layer 3 and the light reflecting material are transmitted. Light is attenuated by the wire 2. The form of the wire grid type polarizing element may be a film-like body or a plate-like body.

  As a material which comprises the base material 1, what is necessary is just to be substantially transparent with respect to the light made into object. For example, inorganic materials such as glass and organic materials such as resins include polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin resin (COP), cross-linked polyethylene resin, polyvinyl chloride resin, polyarylate resin, polyphenylene ether Amorphous thermoplastic resins such as resins, modified polyphenylene ether resins, polyetherimide resins, polyether sulfone resins, polysulfone resins, polyether ketone resins, polyethylene terephthalate (PET) resins, polyethylene naphthalate resins, polyethylene resins, Crystalline thermoplastic resins such as polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal resin, polyamide resin, acrylic, epoxy, urethane, etc. They include ultraviolet (UV) curable resin or thermosetting resin. 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.

  The pitch of the grid-like convex portions 1a of the substrate 1 is determined by the polarization characteristics of the target light, and is generally ½ or less of the wavelength of the light. The smaller the pitch, the better the polarization characteristics. For example, good polarization characteristics can be obtained at 80 to 150 nm for visible light.

  There is no limitation on the cross-sectional shape of the concave portions of the fine concavo-convex lattice formed by the lattice-like convex portions 1a and the plurality of lattice-like convex portions. For example, these cross-sectional shapes may be a sine wave shape such as a trapezoidal shape, a rectangular shape, a square shape, a prism shape, or a semicircular shape. 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 with a constriction in a convex part is also included in a sine wave form.

  Although there is no particular limitation on the method for obtaining the substrate having the lattice-shaped convex portions of the present invention, it is preferable to use the method described in Japanese Patent Application Laid-Open No. 2006-224659 by the present applicant.

  Specifically, in the present invention, as a method I for obtaining a substrate having a lattice-shaped convex portion, a stretched member having a concave-convex lattice with a pitch of 100 nm to 100 μm on the surface is used as a longitudinal direction of the concave-convex lattice (lattice-shaped convex portion). It is preferable to fabricate the stretched member by free end uniaxial stretching in a direction substantially parallel to the longitudinal direction in a state in which the width of the stretched member in a direction substantially orthogonal to the lattice is free. As a result, the pitch of the convex portions of the concavo-convex lattice of the stretched member is reduced, and a base material (stretched member) having a fine concavo-convex lattice 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 refers to a transparent substrate such as a plate-like body, a film-like body, or a sheet-like body composed of an amorphous thermoplastic resin or a crystalline thermoplastic resin as a base material used in the present invention. Can be mentioned. 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 used by changing the angle θ ′. It is possible to obtain an uneven grating structure having various pitches within the laser wavelength range. 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 base material having lattice-shaped convex portions. 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.

  Further, in the present invention, the method II for obtaining a substrate having a lattice-like convex portion is a method of transferring a fine concavo-convex lattice onto the surface of the substrate used in the present invention using a mold having a fine concavo-convex lattice on the surface, and molding It is a method to do. Here, a mold having a fine concavo-convex lattice on the surface is prepared by sequentially performing a conductive treatment, a plating treatment, and a resin base material removal treatment on a base material having a lattice-like convex portion obtained by Method I. Can do.

  According to this method, since the mold having the lattice-shaped convex portions is used, it is possible to mass-produce the substrate having the lattice-shaped convex portions used in the present invention without going through a complicated stretching process. Furthermore, by appropriately combining and repeatedly using Method I and Method II, it becomes possible to produce a finer concavo-convex grid from a concavo-convex grid having a relatively large pitch.

  It is preferable that the light reflecting material constituting the light reflecting material wire 2 has a high reflectance with respect to the target light and has high adhesion with the material constituting the base material 1. For example, it is preferably made of aluminum, silver or an alloy thereof. From the viewpoint of cost, it is more preferable that it is made of aluminum or an alloy thereof.

  As a method of laminating a metal on the base material 1 in order to form the light reflecting material wire 2, for example, a physical vapor deposition method such as a vacuum vapor deposition method, a sputtering method, an ion plating method or the like can be suitably used. The thickness of the light reflecting material wire 2 is preferably 50 nm or more in consideration of not transmitting light.

  The intermediate layer 3 functions as a reflection medium between the light reflecting material wire 2 and the semi-transmissive layer 4, and attenuates light incident together with the light reflecting material wire 2 and the semi-transmissive layer 4. That is, in the intermediate layer 3 sandwiched between the light reflecting material wire 2 and the semi-transmissive layer 4, the light incident on the inside is repeatedly reflected, so that the semi-transmissive layer 4 and / or the light reflecting material wire 2 is reflected. As a result, the reflected light of the light incident from the semi-transmissive layer 4 side is attenuated. For this reason, it is possible to weaken the light (external light reflected light) emitted from the intermediate layer 3 and transmitted through the semi-transmissive layer 4. This intermediate layer 3 preferably contains magnesium fluoride, silicon oxide, aluminum oxide, titanium oxide, zinc oxide, zinc sulfide, aluminum nitride and the like. Further, the thickness of the intermediate layer 3 is determined from the optical relationship with the semi-transmissive layer 4, but is preferably 500 nm or less in consideration of productivity and the like. More preferably, it is 1 nm to 300 nm.

  As a method of laminating the above material on the light reflecting material wire 2 in order to form the intermediate layer 3, for example, a physical vapor deposition method such as a vacuum vapor deposition method or a sputtering method can be suitably used.

  The semi-transmissive layer 4 transmits a part of the light and makes it incident on the intermediate layer 3. This semi-transmissive layer 4 is at least selected from the group consisting of Ti, Hf, V, Nb, Ta, Cr, Mo, W, Co, Rh, Ir, Ni, Pd, Pt, Cu, Al, Si and Ge. It is preferable to include one or a compound of these elements. Further, the thickness of the semi-transmissive layer 4 is determined from the optical relationship with the intermediate layer 3, but is preferably 500 nm or less in consideration of productivity. More preferably, it is 0.1 nm to 100 nm.

  As a method of laminating the above material on the intermediate layer 3 in order to form the semi-transmissive layer 4, for example, a physical vapor deposition method such as a vacuum vapor deposition method or a sputtering method can be suitably used. In this case, it is preferable that the film is formed from a predetermined angle with respect to the standing direction of the light reflecting material wire 2 in a cross sectional view. Thereby, since the film formation in the region shaded by the wire during film formation is suppressed, it is possible to prevent the material of the semi-transmissive layer 4 from being formed in the region between the wires (3a in FIG. 3). This makes it possible to omit the material removal step formed between the wires.

For the semi-transmissive layer 4 and the intermediate layer 3, the inventor performed a simulation on the relationship between the refractive index n and the extinction coefficient k for light having a wavelength of 400 nm to 700 nm. As a result, in order to sufficiently reflect light from the backlight side and suppress reflection of external light as much as possible, the refractive index and extinction coefficient of the intermediate layer 3 are set to n ₁ and k ₁ , respectively. 4 of the refractive index and the extinction coefficient is taken as n _2, k _{2 respectively, k 2> k 1, n} 2> 0.5, it has been found that it is preferable to satisfy the k _2> 0.5 .

  As described above, when the wire grid type polarizing element having the above-described configuration is disposed in a display device having illumination means such as a backlight as shown in FIG. A can be sufficiently reflected by the light reflecting material wire 2 and the external light B can be attenuated by the semi-transmissive layer 4 and the intermediate layer 3 to suppress reflection by the external light B as much as possible. Thereby, sufficient color reproducibility and black display can be realized in the display device.

  In the configuration shown in FIGS. 1 and 2A, when the wire grid type polarizing element is mounted on the display device, the semi-transmissive layer 4 is located on the outside light side, and the base material 1 is located on the backlight side. However, as shown in FIG. 2B, the present invention is not limited to this configuration, and the substrate is provided when the wire grid type polarizing element is mounted on the display device. The present invention can be similarly applied to a configuration in which 1 is located on the outside light side and the light reflecting material wire 2 is located on the backlight side. That is, the wire grid type polarizing element shown in FIG. 2 (b) is formed on the base material 1 in which the lattice-like convex portions 1a are arranged in parallel at predetermined intervals, and on the lattice-like convex portions 1a, and a part of the light. Is made up of a semi-transmissive layer 4 that reflects light and an intermediate layer 3 formed on the semi-transmissive layer 4 and a light-reflective material wire 2 formed on the intermediate layer 3. Also in this case, in the intermediate layer 3 sandwiched between the light reflecting material wire 2 and the semi-transmissive layer 4, the light incident on the inside is repeatedly reflected, so that the semi-transmissive layer 4 and / or the light reflecting material wire is used. As a result, the reflected light of the light incident from the substrate 1 side is attenuated. According to the configuration shown in FIG. 2B, other optical elements can be arranged on the main surface of the base material 1 on the outside light side, and a wire-like body (light reflecting material wire, intermediate layer, The semi-transmissive layer) can be protected with the substrate 1.

  Further, as shown in FIGS. 3A and 3B, the intermediate layer 3 is formed between the lattices of the light reflecting material wire 2 (FIG. 3A) or the semi-transmissive layer 4 (FIG. 3B). The intermediate layer 3 may be continuous. If the intermediate layer is transparent, the light from the backlight is transmitted without being attenuated, so there is no need to remove it and it does not hinder the function, so the etching process can be omitted and the manufacturing can be made more easily. .

  When manufacturing a wire grid type polarizing element having the above-described configuration, first, a substrate 1 having a fine concavo-convex lattice prepared by the above-described method is prepared, and as shown in FIG. A light reflecting material is formed on the lattice-shaped convex portion 1a of the lattice to form the light reflecting material wire 2, and further, for the intermediate layer, on the light reflecting material wire 2, as shown in FIG. The intermediate layer 3 is formed by depositing the above material, and then the semi-transmissive layer 4 is formed by depositing a semi-transmissive material that partially transmits light, as shown in FIG. In this case, the film is formed from a predetermined angle (θ) with respect to the standing direction (X) of the light reflecting material wire 2 in the cross sectional view (C direction).

  Next, the case where the wire grid type polarizing element according to the present invention is used in a liquid crystal display device which is a display device will be described. FIG. 5 is a view showing a liquid crystal display device including the wire grid type polarizing element according to the embodiment of the present invention.

  The liquid crystal display device shown in FIG. 5 is arranged on an illumination device 11 such as a backlight that emits light, a wire grid polarization element 12 disposed on the illumination device 11, and the wire grid polarization element 12. And a liquid crystal cell (display device) 13. That is, the wire grid type polarizing element 12 according to the present invention is disposed between the liquid crystal cell 13 and the illumination device 11. The liquid crystal cell 13 is configured by sandwiching a liquid crystal layer between a pair of substrates. The liquid crystal cell 13 is a transmissive liquid crystal cell, 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. 5, 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 FIG. 5, when the wire grid type polarizing element 12 has the configuration shown in FIGS. 1 and 2A, the substrate 1 of the wire grid type polarizing element 12 is disposed on the illumination device 11, and the wire grid type polarizing element 12 is provided. In the configuration shown in FIG. 2B, the light reflecting material wire 2 of the wire grid type polarizing element is disposed on the illumination device 11.

  In the liquid crystal display device having such a configuration (when the wire grid type polarization element shown in FIG. 1 is provided), the light emitted from the illumination device 11 is incident from the substrate 1 side of the wire grid type polarization element 12 and the light. It passes through the liquid crystal cell 13 from the reflective material wire side and is emitted to the outside (in the direction of the arrow in the figure). In this case, since the wire grid type polarizing element 12 exhibits an excellent degree of polarization in the target light, a display with high contrast can be obtained. On the other hand, part of the external light passes through the liquid crystal cell 13 and enters the intermediate layer 3 through the semi-transmissive layer 4 of the wire grid type polarizing element 12. In the intermediate layer 3, incident light is repeatedly reflected between the light reflecting material wire 2 and the semi-transmissive layer 4 and absorbed by the light reflecting material wire 2 and / or the semi-transmissive layer 4, thereby being attenuated. For this reason, the light reflected by the semi-transmissive layer 4 becomes weak. Therefore, since the light from the illumination device 11 is efficiently reflected and the external light is efficiently absorbed by the wire grid type polarizing element, sufficient color reproducibility and black display can be realized in the liquid crystal display device. .

Next, examples performed for clarifying the effects of the present invention will be described.
Example 1
By the above-described method, a corrugated cross-sectional shape in which the convex tip is tapered on one side of a TAC (Triacetylcellulose) base material by UV transfer with a pitch of 140 nm, a height of about 150 nm, and a width at half height of about 60 nm. A film provided with a fine concavo-convex grid is prepared, and an aluminum film is formed on the grid-shaped convex part of the fine concavo-convex grid by a DC magnetron sputtering method from above at a thickness of about 150 nm by tilting 30 ° from the vertical direction. A reflective material wire was formed, and then the substrate was immersed in a dilute aqueous sodium hydroxide solution to remove excess aluminum adhering between the lattice-shaped convex portions by wet etching.

Next, an intermediate layer was formed by depositing magnesium fluoride with a thickness of 70 nm on the light reflecting material wire from above by magnetron sputtering. Next, chromium was deposited to a thickness of 5 nm from above (θ = 20 ° in FIG. 4C) inclined by 20 ° with respect to the standing direction of the light reflecting material wire to form a semi-transmissive layer. Thus, the wire grid type polarizing element of Example 1 was produced. At this time, the refractive index of chromium is n ₂ = 3.1, the extinction coefficient of chromium is k ₂ = 4.4, the refractive index of magnesium fluoride is n ₁ = 1.4, and the extinction of magnesium fluoride is Since the coefficient is k ₁ = 0, k ₂ > k ₁ , n ₂ > 0.5, and k ₂ > 0.5 are satisfied.

  About the obtained wire grid type polarizing element of Example 1, the vertical reflectance with respect to the light from the backlight side and the vertical reflectance with respect to external light were investigated. Note that the vertical reflectance at this time refers to the reflectance when incident light is incident perpendicularly to the wire grid type polarizing element. Each vertical reflectance was measured with a spectrophotometer. As a result, the vertical reflectance for light from the backlight side was about 60%, and as shown in FIG. 6, the vertical reflectance for external light (wavelength 550 nm) was 2%.

Moreover, about the obtained wire grid type polarizing element of Example 1, the degree of polarization and the transmittance | permeability were measured using the spectrophotometer. Here, the transmitted light intensity in a parallel Nicols state and a crossed Nicols state with respect to linearly polarized light was measured, and the degree of polarization and the transmittance were calculated from the following equations.
Polarization degree = (Imax−Imin) / (Imax + Imin) × 100%
Light transmittance = (Imax + Imin) / 2 × 100%
Here, Imax is the transmitted light intensity at the time of parallel Nicols, and Imin is the transmitted light intensity at the time of crossed Nicols.
As a result, the degree of polarization was 99.4% and the transmittance was 30%.

(Example 2)
Example 1 except that a semi-transparent layer is formed by vapor-depositing chromium to a thickness of 5 nm from above (θ = 60 ° in FIG. 4C) inclined by 60 ° with respect to the standing direction of the light reflecting material wire. Similarly, a wire grid type polarizing element of Example 2 was produced. About the obtained wire grid type polarizing element of Example 2, the vertical reflectance with respect to the light from the backlight side and the vertical reflectance with respect to external light were examined in the same manner as in Example 1. As a result, the vertical reflectance for light from the backlight side was about 60%, and the vertical reflectance for external light (wavelength 550 nm) was 2%. Further, the degree of polarization and the transmittance of the wire grid type polarizing element of Example 2 were measured in the same manner as in Example 1. As a result, the degree of polarization was 99.4% and the transmittance was 32%.

(Example 3)
On the light-reflecting material wire, zinc sulfide is deposited from above with a thickness of 35 nm to form an intermediate layer by magnetron sputtering, and the upper direction inclined by 60 ° with respect to the standing direction of the light-reflecting material wire (see FIG. A wire grid type polarizing element of Example 3 was produced in the same manner as in Example 1 except that chromium was evaporated to a thickness of 5 nm from 4 (c) to form a semi-transmissive layer. At this time, the refractive index of chromium is n ₂ = 3.1, the extinction coefficient of chromium is k ₂ = 4.4, the refractive index of zinc sulfide is n ₁ = 2.4, and the extinction coefficient of zinc sulfide is Since k ₁ = 0, k ₂ > k ₁ , n ₂ > 0.5, and k ₂ > 0.5 are satisfied.

  About the obtained wire grid type polarizing element of Example 3, the vertical reflectance with respect to light from the backlight side and the vertical reflectance with respect to external light were examined in the same manner as in Example 1. As a result, the vertical reflectance for light from the backlight side was about 60%, and the vertical reflectance for external light (wavelength 550 nm) was 3%. Further, the degree of polarization and the transmittance of the wire grid type polarizing element of Example 3 were measured in the same manner as in Example 1. As a result, the degree of polarization was 99.4% and the transmittance was 33%.

(Comparative example)
By the above-described method, a film having a fine concavo-convex grid provided on one side of a TAC substrate by UV transfer is prepared, and the lattice-shaped convex part of the fine concavo-convex grid is inclined by 30 ° from the vertical direction by a DC magnetron sputtering method. From above, aluminum is deposited to a thickness of about 150 nm to form a light-reflective material wire, and then the base material is immersed in a diluted aqueous sodium hydroxide solution to wet excess aluminum adhering between the lattice-shaped protrusions. It was removed by etching. Thus, the wire grid type polarizing element of the comparative example was produced.

  About the obtained wire grid type polarizing element of the comparative example, the vertical reflectance with respect to the light from the backlight side and the vertical reflectance with respect to the external light were examined in the same manner as in Example 1. As a result, the vertical reflectance with respect to light from the backlight side was about 60%, and the vertical reflectance with respect to external light (wavelength 550 nm) was also 60% as shown in FIG. This is presumably because the wire grid type polarizing element does not have a layer for suppressing the reflectance. Further, the degree of polarization and the transmittance of the wire grid type polarizing element of the comparative example were measured in the same manner as in Example 1. As a result, the degree of polarization was 99.4% and the transmittance was 38%.

  As described above, the wire grid polarizing element according to the present invention is provided with the intermediate layer and the semi-transmissive layer on the outside light side, efficiently reflects the light from the illumination device, and attenuates the outside light efficiently to suppress the reflection. Therefore, sufficient color reproducibility and black display can be realized in the liquid crystal display device.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. For example, in the above-described embodiment, the case where the light reflecting material wire is formed on the lattice-like convex portion of the base material in which the lattice-like convex portions are arranged in parallel at a predetermined interval is described. However, the present invention is not limited to this, and the same can be applied to the case where the light reflecting material wires are formed at predetermined intervals on a base material on which no grid-like convex portion is provided. In the above embodiment, the case where the wire grid type polarizing element is applied to a liquid crystal display device is described. However, the present invention is not limited to this, and other display devices (including an illumination device) are used. Can be applied similarly. In addition, the dimensions, materials, and the like in the above embodiment are illustrative, and can be implemented with appropriate changes. In addition, various modifications can be made without departing from the scope of the present invention.

It is a figure which shows the wire grid type polarizing element which concerns on embodiment of this invention. (A), (b) is a figure for demonstrating the layer structure of the wire grid type polarizing element which concerns on embodiment of this invention. (A), (b) is a figure for demonstrating the layer structure of the wire grid type polarizing element which concerns on embodiment of this invention. (A)-(c) is a figure for demonstrating the process of manufacturing the wire grid type polarizing element which concerns on embodiment of this invention. It is a figure which shows the liquid crystal display device equipped with the wire grid type polarizing element which concerns on embodiment of this invention. It is a figure which shows the relationship between a surface reflectance and a wavelength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 1a Lattice-like convex part 2 Light reflecting material wire 3 Intermediate | middle layer 4 Semi-transmissive layer 11 Illumination apparatus 12 Wire grid type polarizing element 13 Liquid crystal cell

Claims (8)

A base material, a light reflecting material wire formed in a lattice shape at a predetermined interval on the base material, an intermediate layer formed on the light reflecting material wire and between the light reflecting material wire lattices , A semi-transmissive layer that is formed on the light reflecting material wire through the intermediate layer and transmits a part of the light to the inside, and the base material has lattice-shaped convex portions at intervals of 80 nm to 150 nm. The intermediate layer formed on the light-reflecting material wire and the intermediate layer formed between the lattices of the light-reflecting material wire are continuous, and the light incident from the transflective layer side is continuous . A wire grid type polarizing element that attenuates reflected light. A base material, a semi-transparent layer formed on the base material at a predetermined interval and transmitting a part of light inside, and formed between the semi-transparent layer and the lattice of the light transmissive layer. And a light-reflecting material wire formed on the light transmission layer via the intermediate layer , and the base material is provided with grid-like convex portions in parallel at intervals of 80 nm to 150 nm. The intermediate layer formed on the semi-transmissive layer and the intermediate layer formed between the lattices of the semi-transmissive layer are continuous, and attenuates the reflected light of the light incident from the base material side. A wire grid type polarizing element. The wire grid type polarizing element according to claim 1, wherein the wire grid type polarizing element is in a film form.   The semi-transmissive layer is at least one selected from the group consisting of Ti, Hf, V, Nb, Ta, Cr, Mo, W, Co, Rh, Ir, Ni, Pd, Pt, Cu, Al, Si, and Ge. The wire grid type polarizing element according to any one of claims 1 to 3, wherein the wire grid type polarizing element includes one or a compound of these elements.   The said intermediate | middle layer contains what was chosen from the group which consists of a magnesium fluoride, a silicon oxide, an aluminum oxide, a titanium oxide, a zinc oxide, a zinc sulfide, and aluminum nitride, Any one of the Claims 1-4 characterized by the above-mentioned. The wire grid type polarizing element according to claim 1. The refractive index of the intermediate layer and the extinction coefficient and _n 1, _{k 1} respectively, wherein the semi-transparent layer of refractive index and extinction coefficient is taken as _n 2, _{k 2 respectively, k 2> k 1, n} 2 > 0.5, the wire grid polarization element according to any one of claims 1 to claim 5, characterized by satisfying the k 2> _0.5.   The wire according to any one of claims 1 to 6, wherein the semi-transmissive layer is formed from a predetermined angle with respect to a standing direction of the light reflecting material wire in a cross sectional view. Grid-type polarizing element. A display device, an illuminating unit that illuminates the display device, and the wire grid type polarizing element according to any one of claims 1 to 7, wherein the wire grid type polarizer includes the light reflecting material. A display device, wherein a wire surface is arranged on the illumination means side.

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