JP2017173742A - Method of manufacturing polarizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure sufficient transmittance of a wire grid polarizer in a wide wavelength range in the visible light region.SOLUTION: The method of manufacturing a polarizer includes; a concavo-convex pattern producing step for producing a periodic structure comprising repetition of a concave groove 11; and a metallic linear parts producing step for depositing a metallic material on the surface of the concavo-convex pattern to produce first metallic linear parts 12 comprising the metallic material provided on the tops of protrusions between the concave grooves 11, and second metallic linear parts 13 comprising the metal material provided on the bottoms of the concave grooves 11. The metallic linear parts producing step involves depositing the metallic material at a deposition incident angle of 6.4 degrees or less to produce the first and second metallic linear parts 12, 13.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a wire grid polarizer.

  Conventionally, in a liquid crystal display device, a liquid crystal cell is formed by sandwiching a liquid crystal material by a glass plate on which a transparent electrode is arranged, and a linear polarizing plate is arranged on both sides of the liquid crystal cell to constitute a liquid crystal display panel. In recent years, a device has been devised in which a reflective linear polarizing plate is arranged on the incident surface (backlight side surface) of the liquid crystal display panel to improve the use efficiency of illumination light by the backlight.

  As such a polarizer, a configuration (so-called sheet polarizer), a wire grid type polarizer, and the like, which are made by impregnating polyvinyl alcohol (PVA) with iodine or the like and then stretching, are used. Patent Documents 1 and 2 propose a device relating to a wire grid polarizer. Patent Document 3 discloses a method of forming a wire grid polarizer by disposing a metal material in a convex portion between concave grooves and a concave portion by concave grooves in a periodic structure by repeating concave grooves. Yes.

  In recent years, liquid crystal display devices have been made thinner. In particular, portable liquid crystal display devices are required to be made thinner. As a result, the components of the liquid crystal display device are also required to be thinned.

  However, a polarizer using a sheet polarizer applied to such a liquid crystal display device has disadvantages that heat resistance is poor and it is difficult to reduce the thickness. Accordingly, it is conceivable to use a wire grid type polarizer instead of the sheet polarizer. However, the conventional wire grid type polarizer has a problem that the transmittance cannot be sufficiently secured in a wide wavelength region of the visible light region. Specifically, for example, in the configuration disclosed in Patent Document 3, the chromatic dispersion is large with respect to the transmittance, and the transmittance is reduced on the short wavelength side, whereby the transmittance cannot be sufficiently secured in a wide wavelength region of the visible light region. There is.

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

  The present invention has been made in view of such a situation, and an object of the present invention is to ensure a sufficient transmittance in a wide wavelength region of a visible light region with respect to a wire grid type polarizer.

  The present inventor has conducted intensive research to solve the above problems, and provided a transparent member made of a transparent resin material having a periodic structure by repeating the concave groove, and a top portion between the concave grooves and a bottom portion of the concave groove, respectively. The first and second metal linear portions are formed to form a polarizer, and the idea is that the metal material related to the metal linear portions is deposited perpendicularly to the surface. It came to be completed.

  Specifically, the present invention provides the following.

(1) A concavo-convex shape production step of producing a periodic structure with a concavo-convex shape by repetition of concave grooves with a pitch equal to or shorter than the shortest wavelength of a wavelength band limiting transmission
By depositing a metal material on the uneven surface, the first metal linear portion by the metal material provided at the top between the concave grooves and the metal material provided at the bottom of the concave groove A metal linear part production step of producing a second metal linear part,
The metal linear part production process includes:
A method for manufacturing a polarizer, wherein the first and second metal linear portions are manufactured by depositing the metal material at a deposition incident angle of 6.4 degrees or less.

  According to (1), the first and second metal materials are deposited so as to grow in the thickness direction so as not to be inclined or biased obliquely on the top between the concave grooves and the bottom surface of the concave grooves. Thus, the wire grid polarizer can be stably produced in such a manner that the transmittance can be sufficiently ensured in a wide wavelength region of the visible light region with respect to the wire grid polarizer.

(2) In (1),
A method for manufacturing a polarizer, comprising an etching step of expanding a gap width between adjacent first metal linear portions.

  According to (2), it is possible to increase the aperture ratio related to the first metal linear portion that has been reduced by the deposition of the metal material, so that it is possible to sufficiently ensure the transmittance in a wide wavelength range of the visible light range. Thus, stable production can be achieved.

  (3) In (1) or (2), the manufacturing method of a polarizer provided with the contact | glue layer preparation process which produces the contact | adherence layer which aims at contact | adhesion of the said metal material in the said uneven | corrugated shaped surface.

  According to (3), the adhesion of the metal linear portion can be improved and the reliability can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the transmittance | permeability can fully be ensured in the wide wavelength range of a visible light region regarding a wire grid type polarizer.

It is a figure which shows the image display apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the polarizer applied to the image display apparatus of FIG. It is a figure where it uses for description of the pitch of the polarizer of FIG. FIG. 4 is a chart for explanation following FIG. 3. It is a flowchart which shows the manufacturing process of the polarizer of FIG. It is a figure where it uses for description of FIG. It is a figure where it uses for description of a vapor deposition incident angle. It is a figure where it uses for description of deposition of the metal material by a vapor deposition incident angle. It is a figure which shows the change of the characteristic by the aperture ratio in a 1st metal linear part. It is a figure which shows the polarizer which concerns on other embodiment.

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

  The polarizer 4 is a wire grid polarizer, and is a so-called reflective polarizer that selectively and efficiently reflects incident light from a polarization plane orthogonal to the transmission axis direction. The polarizer 4 is arranged such that the transmission axis direction of the linearly polarizing plate 7 disposed on the incident surface side (backlight 3 side) of the liquid crystal cell 5 coincides with the transmission axis direction so that the liquid crystal display panel 2 and the backlight 3 are aligned. Thus, the image display device 1 improves the utilization efficiency of the illumination light from the backlight 3. In this embodiment, the polarizer 4 is integrated with the linearly polarizing plate 7 in advance, and then provided to the manufacturing process of the liquid crystal display panel 2, whereby the image display device 1 is assembled by the polarizer 4. Can be simplified. In addition, it may replace with integration with the linearly-polarizing plate 7, and may arrange | position separately.

  This integration is performed by laminating the polarizer 4 and the linearly polarizing plate 7 with an adhesive made of an ultraviolet curable resin or the like, but the layers having optical functions as the polarizer (first and first layers described later). Only the shaping resin layer 16 having the two metal linear portions 12 and 13) may be transferred and executed by the transfer method. The transfer method refers to, for example, when a desired layer is formed on a base material, the layer is not directly formed on the base material, but can be peeled once on a releasable support. After forming the transfer body by laminating the layers, the layer formed on the support is finally placed on the substrate (transfer base material) on which the layer is to be laminated according to the process, demand, etc. In this method, a desired layer is formed on the substrate by bonding and laminating, and then peeling and removing the support.

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

  In the polarizer 4, metal materials are respectively disposed on the tops of the convex portions between the concave grooves 11 according to the periodic structure and the bottom surfaces of the concave portions by the concave grooves 11, and lines are respectively formed on the convex portions (top) and the concave portions. 1st and 2nd metal linear parts 12 and 13 which arrange a metal material in the shape are formed. In the polarizer 4, visible light in which the repetition pitch P of the first and second metal linear portions 12 and 13 (the repetition pitch of the concave grooves 11) is a wavelength band for controlling transmission by the polarizer 4. It is produced with a pitch P (P ≦ λmin) equal to or shorter than the shortest wavelength λmin of the region. Accordingly, the polarizer 4 has a two-layer structure including the first metal linear portion 12 provided on the top between the concave grooves 11 and the second metal linear portion 13 provided on the bottom surface of the concave groove 11. Metal linear portions 12 and 13 are formed and configured to function as a polarizer. In this embodiment, the visible light region has a wavelength of 780 nm or less and 380 nm or more.

  Here, the concave / convex shape due to the repetition of the concave groove 11 is a concave groove 11 having a rectangular cross section with a flat portion in between, whereby the polarizer 4 has a top portion between the concave grooves and a bottom surface of the concave groove. The first and second metal linear portions 12 and 13 are formed by forming the portions with flat surfaces and disposing a metal material with a constant thickness T1 and T2 on the top and bottom portions. Thereby, the 1st and 2nd metal linear parts 12 and 13 are formed by the flat surface in the top part side of a convex part, and the bottom face side of a concave groove corresponding to the top part shape of a convex part, and the bottom part shape of a crevice, respectively. . However, in the top part of the convex part and / or the bottom part of the concave part, for example, it may be formed by a circular arc shape or the like, and various shapes can be widely applied, and thereby the first and second metal wires Various shapes according to the shape of the top part of the convex part and the shape of the bottom part of the concave part can be applied to the shape parts 12 and 13. Correspondingly, various shapes can be applied to the metal linear portions 12 and 13 even if they are on the side opposite to the top side of the convex portion and on the side opposite to the bottom surface side of the concave portion.

  However, simply, the concave groove 11 is repeated with the pitch P of the shortest wavelength λmin or less of the wavelength band for controlling the transmission in this way, and the polarizer 4 is formed by the two-layer structure of the first and second metal linear portions 12 and 13. If formed, the transmittance cannot be sufficiently ensured in a wide wavelength range of the visible light range, which is a wavelength band controlled by the polarizer 4. More specifically, the wavelength dispersion of the transmittance increases, and as a result, the transmittance decreases on the short wavelength side.

  That is, FIG. 3 shows the wavelength dispersion characteristic of the transmittance Tp (transmission axis direction) due to the change of the pitch P in the polarizer by the two-layer structure of the first and second metal linear portions 12 and 13 as described above. FIG. The characteristic curve diagram of FIG. 3 and various characteristics described below are calculated using a simulation software “DiffractMOD” manufactured by Rsofty.

  In FIG. 3, reference numeral L <b> 1 is a case where the pitch P is 100 nm, the gap width S between the first metal linear portions 12 (see FIG. 6E) is 40 nm, and the gap width S with respect to the pitch P is set to 40 nm. The ratio S / P is 0.4, the depth D of the concave groove 11 is 100 nm, and the thicknesses T1 and T2 of the metal linear portions 12 and 13 are 40 nm. Here, the depth D of the concave groove 11 is the depth of the entire groove including the adhesion layer or the like when an adhesion layer or the like to be described later is provided, and the first and second metal linear portions 12 and 13. The distance between the bottom surfaces. In this embodiment, the thicknesses T1 and T2 of the metal linear portions 12 and 13 are average values of measurement results obtained by measuring the thickest portions in the groove width direction at a plurality of locations in the extending direction of the metal linear portions. is there. In this embodiment, even if there is a gap width S or the like, it is an average value of measured values at a plurality of similar positions.

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

  According to the measurement result of FIG. 3, when the pitch P is set to 100 nm which is equal to or shorter than the shortest wavelength in the visible light region, a rapid decrease in the transmittance is observed on the short wavelength side. Deterioration is observed. However, when the pitch P is 64 nm, the deterioration of the wavelength dispersion characteristic related to the transmittance is eliminated, and although not shown in FIG. 3, the deterioration of the wavelength dispersion characteristic is also eliminated in the reflectance. The deterioration of the wavelength dispersion characteristic is also eliminated in the transmittance relating to the polarization component in which the polarization component and the polarization plane are orthogonal to each other as shown in FIG. Thus, in the polarizer in which the metal linear portions 12 and 13 are formed by the two-layer structure, simply repeating the concave groove 11 with a pitch P equal to or less than the shortest wavelength λmin of the wavelength band for controlling the transmission, the visible light region It can be seen that sufficient transmittance cannot be secured in a wide wavelength range. It can also be seen that when the pitch P is 64 nm, such deterioration of characteristics on the short wavelength side is eliminated.

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

  If the measurement result of FIG. 4 is determined with reference to the measurement result of FIG. 3, it can be understood that the deterioration of the wavelength dispersion characteristic related to the transmittance can be practically sufficiently solved when the pitch P is 64 nm or less. On the premise of this pitch P, the ratio S / P of the gap width S between the first metal linear portions 12 to the pitch P is 0.4, and the transmittance Tp at wavelengths of 400 nm, 600 nm, and 800 nm is 80% or more. Thus, even in the transmission in the transmission axis direction, it is possible to secure practically sufficient characteristics, and it is confirmed that these can sufficiently secure the transmittance in a wide wavelength band of the visible light region. The In FIG. 4, although the measurement wavelength on the short wavelength side is 400 nm, the transmittance almost equal to the measurement result at the wavelength of 400 nm in FIG. 4 was measured even at 380 nm, which is the shortest wavelength in the visible light region.

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

  In this measurement result, when the thickness T of the metal linear portions 12 and 13 is 16 nm, the transmittance Ts in the direction orthogonal to the transmission axis direction is 10% or more, but the thickness T is 32 nm, In the case of 48 nm (Nos. 4, 5, and 7), the transmittance Ts rapidly decreases. Thereby, it is preferable that the metal linear parts 12 and 13 are produced with a thickness of 32 nm or more. The maximum value of the thickness of the metal linear portions 12 and 13 is the depth D of the concave groove 11. By making the thickness T of 32 nm or more in this way, the transmittance Ts of incident light whose extending direction of the metal linear portions 12 and 13 is the polarization plane can be made 1.3% or less.

In this measurement result, the polarizer No. 1 to 3, when the pitch P, the ratio S / P, and the thickness T of the metal linear portions 12 and 13 are equal, the change in the depth D of the concave groove 11 causes the direction orthogonal to the transmission axis direction. The transmittance Ts changes greatly. Although this way the concave groove 11 is desirably fabricated by 120nm or more 60nm depth D, and the transmittance T _P according to repeating direction of the metal linear portions 12 and 13 sufficiently secured, more fully in the visible light region From the viewpoint of securing such characteristics, the depth D is desirably 70 nm or more and 100 nm or less, and more desirably 75 nm or more and 85 nm or less.

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

  In the polarizer 4, a molding resin layer 16 related to the transparent member 10 is provided on a base material 15 made of a transparent film material, and a periodic structure related to the concave groove 11 is formed by molding processing of the molding resin layer 16. . In addition, a metal layer is formed on the surface on which the periodic structure is formed by vapor deposition, sputtering, electric field plating, electroless plating, or the like, and the metal linear portions 12 and 13 are manufactured. The polarizer 4 is held in such a manner that the base material 15 is attached to the linearly polarizing plate 7 by an adhesive layer such as an ultraviolet curable resin and integrated. In the opposite direction, the linearly polarizing plate 7 may be attached and held from the metal linear portion 12 side. Further, in this way, the substrate 15 side or the opposite side to the linear polarizing plate 7 side may be disposed separately from the linear polarizing plate 7.

  Here, as this base material 15, various transparent film materials applicable to this kind of optical film can be applied, and a film material having a small optical anisotropy is particularly preferable. In this embodiment, COP (cycloolefin polymer) ) Or TAC (triacetylcellulose) film is applied. However, when a wet process such as etching is applied in the manufacturing process, the TAC film is not preferable because the volume change due to water absorption is large. Moreover, when arrange | positioning the metal linear part 12 at the linear polarizing plate 7 side, you may apply film materials with large optical anisotropy, such as a PET (polyester terephthalate) film, for example. Further, only the shaping resin layer 16 and the first and second metal linear portions 12 and 13 may be arranged on the linearly polarizing plate 7 by a transfer method. In this case, the base material 15 includes a PET film, a polyolefin film, Various base materials can be applied as long as unintentional peeling in the production process does not occur, such as a film with a release layer.

  Although various curable resins that can be subjected to a molding process can be applied to the molding resin layer 16, an ultraviolet curable resin is applied in this embodiment. In addition, in the state which heated the base material 15 and was softened, you may press to a shaping die and may perform a shaping process. In this case, the shaping resin layer 16 will be comprised with the base material 15. .

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

  In this way, instead of providing the shaping resin layer 16 on the base material 15 and producing a periodic structure of continuous concave grooves 11 by the shaping treatment of the shaping resin layer 16, the concave grooves are produced by surface treatment of the glass plate material. Various manufacturing methods can be widely applied to the periodic structure with the concave grooves, for example, when manufacturing this type of periodic structure.

  Although the metal material which concerns on the metal linear parts 12 and 13 can apply the metal, alloy, metal compound, etc. which concern on various conductors widely, for example, the metal by any of aluminum, nickel, chromium, and silver, any of these It is desirable to apply alloys of these metals and compounds of these metals. From the viewpoint of efficiently reflecting electromagnetic waves that restrict transmission, it is desirable to use metals, alloys, and compounds having high reflectivity such as aluminum, nickel, and silver, and aluminum is particularly preferable for visible light. On the other hand, from the viewpoint of suppressing the reflection of electromagnetic waves that limit transmission, it is desirable to apply a metal, alloy, or compound having a low reflectance such as chromium.

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

  The metal linear portions 12 and 13 can be produced by vapor deposition or sputtering, and chemical vapor deposition, atomic layer deposition, or the like can also be applied.

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

  More specifically, in this uneven shape manufacturing step, as shown in FIG. 6 (A), first, after applying an ultraviolet curable resin coating liquid to the base material 15, fine uneven shapes are formed on the peripheral side surface. While the base plate 15 is pressed and conveyed to the roll plate that is being manufactured, the ultraviolet curable resin is cured by irradiating ultraviolet rays, and then the cured ultraviolet curable resin is used as the base material 15. And peeled off from the roll plate. Thereby, in this step, as shown in FIG. 6B, the fine concavo-convex shape formed on the peripheral side surface of the roll plate is transferred to produce the concavo-convex shape by repeating the concave grooves 11 on the surface of the substrate 15. To do.

Subsequently, the manufacturing process of the polarizer 4 is provided with an adhesion layer preparation step SP3 as necessary. In this adhesion layer preparation process SP3, the adhesion layer is formed on the surface of the shaped resin layer 16 having the concavo-convex shape thus prepared. 17 is manufactured (FIG. 6C). More specifically, in this embodiment, the SiO _x layer is produced by sputtering.

  Subsequently, in this manufacturing process, in the metal linear part manufacturing process SP4, as shown in FIG. 6 (D), a metal material is applied to the entire surface of the concave and convex shape formed by forming the concave groove 11 by vapor deposition, sputtering, or the like. Deposit. Here, when the metal material is deposited on the concave / convex shape surface formed with the concave groove 11 in this manner, the incoming metal material is sequentially deposited on the top portion between the concave grooves 11 related to the concave / convex shape, so that the first The metal linear portion 12 is formed. On the other hand, in the metal material which arrives at the concave groove 11, it penetrates into the concave groove 11 and is deposited on the bottom surface. As a result, the second metal linear portion 13 is formed. Thereby, in this embodiment, the 1st and 2nd metal linear parts 12 and 13 are produced.

  However, when the metal linear portions 12 and 13 are simply produced by depositing a metal material by vapor deposition, sputtering, etc., the optical characteristics vary in various ways, so that stable and sufficient in a wide wavelength range of visible light range It was found that the transmittance could not be secured. Therefore, in this embodiment, the metal linear portions 12 and 13 are produced by depositing a metal material at an evaporation incident angle of 6.4 degrees or less.

  Here, the vapor deposition incident angle is an angle that defines the arrival direction of the vapor deposition material, and is an angle formed by this vertical direction and the direction of the vapor deposition source, where the vertical direction of the vapor deposition target portion is 0 degree. As shown in FIG. 7, the adhesion layer 17 and the base material 15 which produced the uneven | corrugated shaped surface were arrange | positioned on the surrounding side surface of the roll by a cylindrical shape, and deposition of the metal material by vapor deposition was observed. In addition, the base material 15 was arrange | positioned in the direction in which the extension direction of the concave groove 11 became parallel to the extension direction of the central axis of a roll. Here, when the vapor deposition incident angle θ is small, as shown in FIG. 8A, a metal material layer grows on the top of the concave grooves 11 and on the bottom surface of the concave grooves 11 toward the arrival direction of the metal material. Thus, the first and second metal linear portions 12 and 13 are formed as if the thickness is increased.

  On the other hand, when the vapor deposition incident angle θ increases, a metal material layer grows on the top portion between the concave grooves 11 and the bottom surface of the concave groove 11 toward the arrival direction of the metal material corresponding to the vapor deposition incident angle θ. A first metal linear portion 12 is formed. As a result, as shown in FIG. 8B, the first metal linear portion 12 is formed to be inclined in the direction related to the vapor deposition incident angle θ. In addition, the second metal linear portion 13 is formed to have an insufficient thickness due to the fact that the metal material does not sufficiently enter the concave groove 11 and is further biased toward the bottom surface. Here, when the first metal linear portion 12 is formed so as to be inclined in this manner, the gap width S (see FIG. 6E) between the adjacent metal linear portions 12 decreases, The aperture ratio related to the first metal linear portion 12 is reduced. When the aperture ratio decreases in this way, and further, when the thickness of the second metal linear portion 13 related to the bottom surface becomes thin, the optical characteristics of the polarizer deteriorate, and the light is sufficiently transmitted in a wide wavelength region of the visible light region. The rate cannot be secured.

  Here, the vapor deposition incident angle θ is different for each part to be vapor-deposited. Thus, when the metal linear parts 12 and 13 are produced by simply depositing a metal material by vapor deposition, sputtering or the like, various optical characteristics are obtained in each part. As a result, it was found that the transmittance could not be secured stably and sufficiently in a wide wavelength range of the visible light range.

  As a result of various examinations, the inclination of the first metal linear portion 12 and the thickness and the deviation of the second metal linear portion have a deposition incident angle of 6.4 degrees or less, more preferably a deposition incident angle 4. The metal material can be deposited at a degree less than that, which can be sufficiently reduced in practical use, thereby sufficiently reducing the variation in characteristics over the entire surface of the polarizer and ensuring sufficient transmittance in a wide wavelength range of the visible light range. I found it impossible.

  For this reason, in this embodiment, as schematically shown in FIG. 7, a slit SH having an opening in a range of ± 6.4 degrees centered on a deposition incident angle of 0 degrees is provided between the deposition source and the deposition target. The metal material is deposited at a deposition incident angle of 6.4 degrees or less. Instead of this, or in addition to this, a sufficiently large deposition source is prepared for the deposition target, or the deposition target is curved so that the vertical direction of each part of the deposition target becomes the direction of the deposition source. You may arrange by.

  When the metal material is deposited in this manner to produce the first and second metal linear portions 12 and 13, this manufacturing process is performed between the adjacent first metal linear portions 12 by the etching step SP5. The gap width S is increased.

  That is, when depositing a metal material by vapor deposition, sputtering, etc., the metal material will also adhere to the wall surface of the concave groove 11 between the first and second metal linear portions 12, 13, The metal material adhering to the wall surface is a very small amount and is thin, so that the metal linear portions 12 and 13 do not function as a metal material layer, and the metal linear portions 12 and 13 are adjacent to each other in the width direction. Insulating properties are ensured between the polarizer 13 and the polarizer 4, and the selectivity of the transmittance by the polarization plane is ensured.

[Etching process]
However, in the case of depositing a metal material by vapor deposition, for example, depending on the metal material deposition conditions such as the vapor deposition rate, as shown in FIG. In addition, the metal material grows in the width direction, and as a result, the gap width S between the adjacent first metal linear portions 12 may be extremely reduced. When the gap width S is extremely reduced in this way, the aperture ratio in the first metal linear portion 12 (the ratio of the portion of the gap width S in the repetition direction of the metal linear portion 12) is reduced, and as a result, The transmittance will decrease.

  Thus, in this embodiment, the aperture ratio is increased by etching using an etching solution. 9A and 9B are characteristic curve diagrams showing changes in characteristics due to this etching. In FIG. 9, Tp and Ts are transmittances in the transmission axis direction and the absorption axis direction, respectively, and Rp and Rs are reflectances in the transmission axis direction and the absorption axis direction, respectively. In addition, the pitch P is 64 nm, the concave groove 11 is an example in which the depth D is 60 nm, the thickness T (= T1, T2) of the metal linear portions 12 and 13 is 40 nm, and the gap width S is 30 nm. The metal material is aluminum. In FIG. 9A, the gap width S between the adjacent first metal linear portions 12 is 20 nm at the minimum, and in this example, the change in the transmittance Tp in the transmission axis direction is significant, and the transmittance is also high. It turns out that it is also small. It can also be seen that the reflectance Rp in the direction of the transmission axis is also large.

  On the other hand, FIG. 9B shows a case where the polarizer having the structure shown in FIG. 9A is applied to an etching solution (temperature 23 ° C.) with a sodium hydroxide aqueous solution having a concentration of 0.01 mol / l in a range of 40 ± 5 seconds. It is pickled in. As a result, the minimum gap width S between the adjacent first metal linear portions 12 changed to 36 to 40 nm, and the thickness T changed from the original thickness to a range of less than −3 nm. According to FIG. 9B, it can be seen that the characteristics are improved and a sufficient transmittance can be secured in a wide wavelength range of the visible light range. In the etching process, the thickness T of the metal linear portion 12 is also reduced, but the gap width S can be quickly increased as compared with the reduction of the thickness T. However, if the etching time is too long, the thickness of the second metal contact portion 13 becomes thin and the optical characteristics deteriorate, and in particular, the reflectance Rs in the absorption axis direction rapidly decreases. However, if the etching time is too short, the transmittance Tp in the transmission axis direction decreases. Thus, the etching time is desirably 10 seconds or more and 60 seconds or less when etching is performed at a liquid temperature of 15 degrees or more and 34 degrees or less with a sodium hydroxide aqueous solution having a concentration of 0.005 mol / l or more and 0.015 mol / l or less.

  Instead of such wet etching, the gap width S may be widened by so-called dry etching. Further, when the gap width S is sufficiently secured in practice, the etching process may be omitted. This etching process also removes all or part of the metal material adhering to the wall surface of the concave groove 11, thereby improving the insulation between the first and second metal linear portions 12, 13 and improving the characteristics. Can be improved.

  Thus, when the metal linear parts 12 and 13 are produced, this manufacturing process is wound up on a roll to produce a polarizer winding body, and this polarizer winding body is conveyed to a subsequent processing step to be linearly polarized. Integration processing with a board, cutting processing, etc. are performed. The polarizer 4 may be integrated with the linear polarizing plate 7 after being cut into a desired shape. In the manufacturing process, a long film-shaped base material is cut at a constant pitch during the manufacturing process. For example, in a vapor deposition process used for the production of a metal linear part, it is executed by processing a sheet-like base material. May be.

  According to the above configuration, a metal material is deposited at a deposition incident angle of 6.4 degrees or less to produce the first and second metal linear portions, so that the wire grid polarizer has a wide visible light range. Stable production can be achieved by ensuring sufficient transmittance in the wavelength range.

  In addition, by providing an etching step for expanding the gap width between the adjacent first metal linear portions, it is possible to ensure a sufficient transmittance in a wide wavelength region of the visible light region and stably produce.

  In addition, high reliability can be ensured by including an adhesion layer manufacturing process for manufacturing an adhesion layer for adhesion of a metal material.

[Other Embodiments]
The specific configuration suitable for the implementation of the present invention has been described in detail above. However, the present invention is not limited to the scope of the present invention, and various combinations of the above-described embodiments, and further the configuration of the above-described embodiments. Can be variously changed.

  That is, in the above-described embodiment, the case where the concave groove is formed with a rectangular cross section is described. However, the present invention is not limited to this, and as shown in FIG. 10A, the opposing wall surfaces are tapered tapered surfaces. A concave groove may be formed with a wedge-shaped cross section, and as shown in FIG. 10 (B), the concave groove may be formed with a cross-sectional shape having a concavo-convex surface shape with a sinusoidal shape as a whole. The shape can be applied.

  Further, in the above-described embodiment, the case where the polarizer according to the present invention is disposed between the liquid crystal cell and the backlight has been described for the liquid crystal display device. However, the present invention is not limited thereto, and for example, a metal linear portion is provided. It may be arranged in place of the linearly polarizing plate constituting the liquid crystal cell so that the reflectance is sufficiently suppressed by being produced by a multilayer.

  In the above-described embodiment, the case where the present invention is applied to the image display device according to the liquid crystal display device has been described. However, the present invention is not limited to this, and may be applied to an image display device using a projector. Can be widely applied to.

DESCRIPTION OF SYMBOLS 1 Image display apparatus 2 Liquid crystal display panel 3 Backlight 4 Polarizer 5 Liquid crystal cell 6, 7 Linear polarizing plate 10 Transparent member 11 Concave groove 12, 13 Metal linear part 15 Base material 16 Molding resin layer 17 Adhesion layer SH Slit

Claims (3)

Concave and convex shape production process for producing a periodic structure with a concave and convex shape by repeating concave grooves with a pitch equal to or less than the shortest wavelength of the wavelength band limiting transmission,
By depositing a metal material on the uneven surface, the first metal linear portion by the metal material provided at the top between the concave grooves and the metal material provided at the bottom of the concave groove A metal linear part production step of producing a second metal linear part,
The metal linear part production process includes:
A method for manufacturing a polarizer, comprising depositing the metal material at a vapor deposition incident angle of 6.4 degrees or less to produce the first and second metal linear portions. The method for producing a polarizer according to claim 1, further comprising an etching step of enlarging a gap width between the adjacent first metal linear portions. The manufacturing method of the polarizer of Claim 1 or Claim 2 provided with the contact | glue layer preparation process which produces the contact | adherence layer which adheres the said metal material on the said uneven | corrugated shaped surface.

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