JP6423124B1 - Polarizing plate, method for producing the same, and optical instrument - Google Patents

Abstract

Provided are a polarizing plate that can improve the durability of a polarizing plate and the productivity of an optical device, a manufacturing method thereof, and an optical device.
A polarizing plate 1 having a wire grid structure is arranged on a transparent substrate 2 and a transparent substrate 2 on one surface side of the polarizing plate 1 at a pitch shorter than the wavelength of light in a use band, and is predetermined. A water-repellent layer 4 that covers the surface of the lattice-shaped convex portion 3 is formed on one surface of the polarizing plate 1. It is the polarizing plate 1 in which the water repellent layer 4 is not formed.
[Selection] Figure 2

Description

  The present invention relates to a polarizing plate, a manufacturing method thereof, and an optical apparatus.

  The polarizing plate is an optical element that absorbs polarized light in the absorption axis direction and transmits polarized light in the transmission axis direction orthogonal thereto. In recent years, an absorption type polarizing plate having a wire grid structure is used in an optical apparatus such as a liquid crystal projector. In order to satisfy desired optical characteristics in the visible light band, this absorption type polarizing plate needs to have a grid period in the submicron order. Therefore, the width of each layer of the reflective layer, the dielectric layer, and the absorbing layer constituting the grid is several tens of nm.

  By the way, the polarizing plate is used in a high humidity and dust (PM2.5 or the like) environment, and since it is an absorption type, the grid is exposed to a high temperature under actual use. Therefore, the grid surface is oxidized and corroded, and even if only the surface is oxidized or corroded, the optical characteristics are greatly affected because the size is nano-order. Therefore, various techniques for improving the durability of the polarizing plate while avoiding the adverse effect on the optical characteristics have been proposed.

  For example, a polarizing plate having a monomolecular layer made of a corrosion inhibitor on the surface of a polarizing plate having a wire grid structure is disclosed (for example, see Patent Document 1). According to this polarizing plate, by setting the thickness of the monomolecular layer to less than about 100 angstroms, corrosion can be prevented without adversely affecting the optical characteristics.

  Also, for example, on the surface of a polarizing plate having a wire grid structure, a standard region having standard characteristics arranged in the center of the polarizing plate, and a modification having characteristics different from the standard characteristics arranged at the end of the polarizing plate And a polarizing plate provided with a region (see, for example, Patent Document 2). According to this polarizing plate, the adjacent grids are fused together by crushing the grid in the correction region, thereby preventing the grid from corroding due to the ingress of fluid such as fat or water from the end due to the capillary phenomenon. It is said that.

  Further, for example, a polarizing plate is disclosed in which inorganic fine particles such as silica are coated on the surface of a polarizing plate having a wire grid structure (see, for example, Patent Document 3). According to this polarizing plate, since the surface is provided with an inorganic protective film such as a silica layer, the durability can be improved.

JP-T-2006-507517 JP 2013-218294 A JP 2012-103728 A

  By the way, in a 3LCD type liquid crystal projector, for example, three types of liquid crystal panels corresponding to each color of blue, green and red are used, and polarizing plates are arranged on the incident side and the emission side so as to sandwich each liquid crystal panel. . In order to reduce the thermal load of each polarizing plate, a polarizing plate with a low extinction ratio called a pre-polarizing plate may be disposed in front of the polarizing plate on the incident side. If the number is included, the maximum is nine. Therefore, facilitating identification of the polarizing plate is important from the viewpoint of preventing human error and improving the productivity of optical equipment such as a liquid crystal projector.

  As a method for identifying a polarizing plate, there is a method of printing product information using a laser marking, a marking pen, a diamond cutter, or the like on the invalid surface of the front or back surface of the polarizing plate or the side surface of the end of the polarizing plate. Can be mentioned. When the invalid area is small and printing is difficult, printing is necessarily performed on the side surface of the end portion. In this regard, in the conventional general formation of the protective film, the protective film is formed not only on the surface of the polarizing plate but also on the side surface. If printing is performed on the side surface, the protective film may be peeled off and cause dust. In particular, when the protective film is a water repellent film, there is a possibility that printing cannot be performed with a marking pen. Furthermore, in a polarizing plate like patent document 2, as a result of the crushed grid covering the side surface of an edge part, there exists a possibility of causing a trouble in marking.

  This invention is made | formed in view of the above, and it aims at providing the polarizing plate which can improve the durability of a polarizing plate, and the productivity of an optical instrument, its manufacturing method, and an optical instrument.

  In order to achieve the above object, the present invention provides a polarizing plate having a wire grid structure (for example, a polarizing plate 1 described later), a transparent substrate (for example, a transparent substrate 2 described later), and one surface of the polarizing plate. A grid-like convex part (for example, a grid-like convex part 3 to be described later) arranged in a pitch shorter than the wavelength of light in the use band on the transparent substrate on the side, and extending in a predetermined direction. A water-repellent layer (for example, a water-repellent layer 4 and 41 described later) is formed on one surface of the polarizing plate, and a water-repellent layer is formed on the side surface of the polarizing plate. Provide no polarizing plate.

  The transparent substrate may be exposed on a side surface of the polarizing plate.

  An identification marking may be provided on a side surface of the polarizing plate.

  A water repellent layer (for example, water repellent layers 42 and 4 described later) may be formed on the other surface of the polarizing plate.

  The water repellent layer may have, in order from the transparent substrate side, a silica layer made of silica and a silane coupling layer made of a silane coupling agent.

  The silane coupling layer may contain fluorine.

  The transparent substrate may be transparent to the wavelength of light in the use band, and may be made of glass, crystal, or sapphire.

  You may further provide the heat conductive board which is arrange | positioned on the other surface of the said transparent substrate, and consists of sapphire.

  The present invention also relates to a method of manufacturing a polarizing plate having a wire grid structure, wherein a predetermined direction is formed at a pitch shorter than the wavelength of light in the use band on one surface side of the transparent substrate larger than the use size of the polarizing plate. And forming a water-repellent layer that covers the surface of the transparent substrate and the surface of the lattice-shaped convex portion on one surface side of the transparent substrate. There is provided a method for producing a polarizing plate, comprising: a water layer forming step; and a cutting step of cutting the transparent substrate on which the water repellent layer is formed into the use size.

  The present invention also relates to a method of manufacturing a polarizing plate having a wire grid structure, wherein the pitch is shorter than the wavelength of light in the used band on one surface side of the transparent substrate having the same size as the used size of the polarizing plate. A grid-shaped convex portion forming step for forming a grid-shaped convex portion extending in a predetermined direction, and a water repellent layer covering the surface of the transparent substrate and the surface of the grid-shaped convex portion on one surface side of the transparent substrate. There is provided a method for producing a polarizing plate comprising: a water repellent layer forming step to be formed; and a removing step of removing the water repellent layer formed on the side surface of the transparent substrate by etching.

  The present invention also provides an optical apparatus comprising the polarizing plate according to any one of the above inventions.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to improve the durability of a polarizing plate, the polarizing plate which can improve the productivity of an optical instrument, its manufacturing method, and an optical instrument can be provided.

It is a perspective view of the polarizing plate which concerns on one Embodiment of this invention. It is sectional drawing of the polarizing plate which concerns on the said embodiment. It is a figure for demonstrating the manufacturing method of the polarizing plate which concerns on the said embodiment. It is a figure for demonstrating the manufacturing method of the polarizing plate which concerns on the said embodiment. It is a figure for demonstrating the manufacturing method of the polarizing plate which concerns on the said embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[Polarizing plate 1]
A polarizing plate 1 according to an embodiment of the present invention is an inorganic polarizing plate having a wire grid structure. The polarizing plate 1 according to the present embodiment is arranged on the transparent substrate 2 and the transparent substrate 2 on one surface side of the polarizing plate 1 with a pitch (period) shorter than the wavelength of light in the use band and extends in a predetermined direction. And a grid-like convex portion 3. In addition, a water repellent layer 4 is formed on one surface of the polarizing plate 1 so as to cover the surface of the lattice-shaped convex portion 3, while a water repellent layer is not formed on the side surface of the polarizing plate 1. It is a feature.

FIG. 1 is a perspective view of a polarizing plate 1 according to this embodiment. FIG. 2 is a cross-sectional view of the polarizing plate 1 according to this embodiment.
As shown in FIGS. 1 and 2, the extending direction (predetermined direction) of the grid-like convex portion 3 is referred to as a Y-axis direction. A direction perpendicular to the Y-axis direction and in which the grid-like convex portions 3 are arranged along the main surface of the transparent substrate 2 is referred to as an X-axis direction. In this case, the light incident on the polarizing plate 1 is preferably incident from the direction orthogonal to the X-axis direction and the Y-axis direction on the side of the transparent substrate 2 on which the grid-like convex portions 3 are formed.

  The polarizing plate 1 utilizes four actions of selective light absorption of a polarized wave due to transmission, reflection, interference, and optical anisotropy, thereby causing a polarized wave (TE wave (S wave (S) (S wave (S)) to be parallel to the Y-axis direction. Wave)) is attenuated, and a polarized wave (TM wave (P wave)) having an electric field component parallel to the X-axis direction is transmitted. Accordingly, the Y-axis direction is the direction of the absorption axis of the polarizing plate 1, and the X-axis direction is the direction of the transmission axis of the polarizing plate 1.

  The transparent substrate 2 is not particularly limited as long as it is a substrate exhibiting translucency with respect to light in the use band, and can be appropriately selected according to the purpose. “Showing translucency with respect to the light in the use band” does not mean that the light transmittance in the use band is 100%, but the translucency capable of maintaining the function as a polarizing plate. Show it. Examples of the light in the use band include visible light having a wavelength of about 380 nm to 810 nm.

  The main surface shape of the transparent substrate 2 is not particularly limited, and a shape (for example, a rectangular shape) according to the purpose is appropriately selected. The average thickness of the transparent substrate 2 is preferably 0.3 mm to 1 mm, for example.

  The constituent material of the transparent substrate 2 is preferably a material having a refractive index of 1.1 to 2.2, and examples thereof include glass, crystal, and sapphire. From the viewpoint of cost and light transmittance, it is preferable to use glass, particularly quartz glass (refractive index 1.46) or soda lime glass (refractive index 1.51). The component composition of the glass material is not particularly limited, and for example, an inexpensive glass material such as silicate glass widely distributed as optical glass can be used.

  From the viewpoint of thermal conductivity, it is preferable to use quartz or sapphire having high thermal conductivity. Thereby, high light resistance with respect to strong light is obtained, and it is preferably used as a polarizing plate for an optical engine of a projector that generates a large amount of heat. Alternatively, a heat conduction plate made of sapphire may be disposed on the other surface of the transparent substrate 2. By disposing the heat conductive plate in contact with the other surface of the transparent substrate 2, high heat resistance is obtained, and the durability of the polarizing plate 1 is improved.

  When a transparent substrate made of an optically active crystal such as quartz is used, it is preferable to arrange the lattice-shaped convex portions 3 in a direction parallel to or perpendicular to the optical axis of the crystal. Thereby, excellent optical characteristics can be obtained. Here, the optical axis is a direction axis that minimizes the difference in refractive index between O (ordinary ray) and E (extraordinary ray) of light traveling in that direction.

  The grid-shaped convex portions 3 are arranged in a one-dimensional manner on one surface of the transparent substrate 2 at a pitch shorter than the wavelength of light in the use band, and extend in a predetermined direction. The grid-like convex portion 3 is formed in a quadrangular prism shape extending vertically from the transparent substrate 2. The lattice-shaped convex portion 3 is configured by laminating a reflection layer, a dielectric layer, and an absorption layer (not shown) in order from the transparent substrate 2 side. That is, the polarizing plate 1 according to the present embodiment is an absorptive polarizing plate having a wire grid structure.

  Therefore, part of the light incident from the side of the polarizing plate 1 on which the lattice-like convex portions 3 are formed is absorbed and attenuated when passing through the absorption layer and the dielectric layer. Of the light transmitted through the absorption layer and the dielectric layer, the polarized wave (TM wave (P wave)) is transmitted through the reflection layer with high transmittance. On the other hand, of the light transmitted through the absorption layer and the dielectric layer, the polarized wave (TE wave (S wave)) is reflected by the reflection layer. The TE wave reflected by the reflective layer is partially absorbed when passing through the absorbing layer and the dielectric layer, and partially reflected and returns to the reflective layer. Further, the TE wave reflected by the reflection layer is attenuated by interference when passing through the absorption layer and the dielectric layer. As described above, the polarizing plate 1 can obtain desired polarization characteristics by selectively attenuating the TE wave.

  Here, the height of the grid-like convex part 3 means a dimension in a direction perpendicular to the main surface of the transparent substrate 2, and the width of the grid-like convex part 3 means Y along the extending direction of the grid-like convex part 3. When viewed from the axial direction, it means the dimension in the X-axis direction orthogonal to the height direction. Further, when the polarizing plate 1 is viewed from the Y-axis direction along the direction in which the lattice-shaped convex portions 3 extend, the repetition interval in the X-axis direction of the lattice-shaped convex portions 3 is referred to as a pitch P.

  It is preferable that the height of the lattice-shaped convex part 3 is 10 nm or more. When the height of the grid-like convex portions 3 is 10 nm or more, desired optical characteristics can be obtained, and more excellent water repellency is exhibited. The height of the grid-like convex portions 3 can be measured by observing with a scanning electron microscope or a transmission electron microscope. For example, using a scanning electron microscope or a transmission electron microscope, the height of the grid-like convex portions 3 can be measured at any four locations, and the arithmetic average value can be set as the height of the grid-like convex portions 3. Hereinafter, this measurement method is referred to as electron microscopy.

  It is preferable that the width | variety of the grid-shaped convex part 3 is 35-45 nm. When the width of the grid-like convex portion 3 is within this range, desired optical characteristics can be obtained and more excellent water repellency is exhibited. The width of the grid-shaped convex portion 3 can be measured by, for example, the above-described electron microscopy.

  The pitch P (see FIG. 2) of the lattice-shaped convex portions 3 is not particularly limited as long as it is shorter than half of the wavelength of light in the use band. From the viewpoint of ease of fabrication and stability, the pitch P of the lattice-shaped convex portions 3 is preferably, for example, 100 nm to 200 nm. When the pitch P of the lattice-like convex portions 3 is within this range, desired optical characteristics can be obtained and more excellent water repellency is exhibited. The pitch P of the grid-like convex portions 3 can be measured by, for example, the above-described electron microscopy.

The reflective layer is composed of a metal film extending in a band shape in the Y-axis direction that is the absorption axis. The reflection layer attenuates a polarized wave (TE wave (S wave)) having an electric field component in a direction parallel to the longitudinal direction of the reflection layer, and a polarized wave (TM) having an electric field component in a direction orthogonal to the longitudinal direction of the reflection layer. Wave (P wave)).
The constituent material of the reflective layer is not particularly limited as long as it is a material having reflectivity with respect to light in the use band. For example, Al, Ag, Cu, Mo, Cr, Ti, Ni, W, Fe, Si, Examples thereof include an elemental element such as Ge or Te or an alloy containing one or more of these elements. Especially, it is preferable that a reflection layer is comprised with aluminum or aluminum alloy. In addition to these metal materials, the reflective layer may be composed of an inorganic film or a resin film other than a metal formed with a high surface reflectance by, for example, coloring.

The dielectric layer is formed on the reflective layer, and is formed by arranging dielectric films extending in a band shape in the Y-axis direction that is the absorption axis. Examples of the material constituting the dielectric layer include Si oxides such as SiO ₂ , metal oxides such as Al ₂ O ₃ , beryllium oxide and bismuth oxide, MgF ₂ , cryolite, germanium, titanium dioxide, silicon, fluorine, and the like. Common materials such as magnesium chloride, boron nitride, boron oxide, tantalum oxide, carbon, or a combination thereof can be given. Especially, it is preferable that a dielectric material layer is comprised with Si oxide.

The absorption layer is formed on the dielectric layer and is arranged extending in a band shape in the Y-axis direction that is the absorption axis. Examples of the constituent material of the absorption layer include one or more kinds of substances having a light absorption function, such as a metal material or a semiconductor material, whose extinction constant of the optical constant is not zero, and are appropriately selected depending on the wavelength range of light to be applied. The Examples of the metal material include elemental elements such as Ta, Al, Ag, Cu, Au, Mo, Cr, Ti, W, Ni, Fe, and Sn, or alloys containing one or more of these elements. Examples of the semiconductor material include Si, Ge, Te, ZnO, and silicide materials (β-FeSi ₂ , MgSi ₂ , NiSi ₂ , BaSi ₂ , CrSi ₂ , CoSi ₂ , TaSi, etc.). By using these materials, the polarizing plate 1 can obtain a high extinction ratio with respect to an applied visible light region. Especially, it is preferable that an absorption layer is comprised including Si while containing Fe or Ta.

  The water repellent layer 4 is formed on one surface of the polarizing plate 1, that is, the surface on which the lattice-like convex portions 3 are formed, and covers the surface of the lattice-like convex portions 3. In the present embodiment, as shown in FIG. 2, the water repellent layer 4 is also formed in each groove between the adjacent grid-like convex portions 3, and the water repellent layer is covered so as to cover the entire one surface of the polarizing plate 1. 4 is formed. Thus, for example, even when water droplets adhere to one surface of the polarizing plate 1 due to condensation or the like, it is usually placed vertically in the optical apparatus such as a liquid crystal projector (the thickness direction of the polarizing plate 1 is substantially horizontal). Water droplets quickly flow and are removed from one surface of the polarizing plate 1 arranged in this manner without staying for a long time. For this reason, it is possible to avoid a situation in which spots and the like are caused by absorbing dust in the atmosphere while water droplets remain attached for a long time, and adversely affect the optical characteristics. That is, excellent moisture resistance is obtained, and the durability of the polarizing plate 1 can be improved.

  Moreover, the surface of the grid-like convex part 3 can be protected by covering the surface of the grid-like convex part 3 with the water-repellent layer 4. Therefore, oxidation and corrosion on the surface of the grid-like convex portion 3 can be prevented, and the durability of the polarizing plate 1 can be improved.

  In this embodiment, the water repellent layer 4 is also formed on the other surface of the polarizing plate 1 so as to cover the entire other surface of the polarizing plate 1. Thereby, also on the other surface of the polarizing plate 1, spots and the like are generated by absorbing dust and the like in the atmosphere with water droplets attached for a long time, and a situation that adversely affects the optical characteristics can be avoided. That is, more excellent moisture resistance can be obtained, and the durability of the polarizing plate 1 can be further improved.

  The thickness of the water repellent layer 4 is not particularly limited. It can be set as appropriate as long as the optical characteristics of the polarizing plate 1 are not adversely affected. Specifically, the preferable thickness of the water repellent layer 4 is 1 to 3 nm.

  The water repellent layer 4 preferably has, in order from the transparent substrate 2 side, a silica layer (not shown) made of silica and a silane coupling layer (not shown) made of a silane coupling agent.

  The silica layer is composed of silica. The silica layer is formed so as to cover the entire surface of the transparent substrate 2 and the surface of the lattice-like convex portion 3. Silanol groups are present on the surface of the silica layer, and undergo a condensation reaction with a silane coupling agent in a silane coupling layer described later that is laminated so as to cover the surface of the silica layer. Thereby, as a result of the silane coupling layer being firmly bonded onto the silica layer, peeling of the silane coupling layer can be prevented. Therefore, the polarizing plate 1 according to the present embodiment can maintain excellent water resistance, moisture resistance and antifouling properties for a long period of time, and has high durability.

  The silica layer preferably has a thickness of 20 nm or less. When the thickness of the silica layer is 20 nm or less, excellent water resistance, moisture resistance, and antifouling properties can be maintained for a long time while maintaining desired optical characteristics. The thickness of the silica layer is preferably 1/10 or less of the pitch P. Thereby, the more excellent water resistance, moisture resistance, and antifouling property can be maintained for a long time. The silica layer can be formed by using, for example, CVD (Chemical Vapor Deposition) or ALD (Atomic Layer Deposition).

  The silane coupling layer is composed of a silane coupling agent. The silane coupling layer is formed so as to cover the entire surface of the silica layer. As described above, the silane coupling agent constituting the silane coupling layer is strongly bonded by a condensation reaction with a silanol group present on the surface of the silica layer.

  The silane coupling layer preferably contains fluorine. More specifically, the silane coupling layer is preferably composed of a fluorine-based silane coupling agent such as perfluorodecyltriethoxysilane (FDTS). Thereby, more excellent water resistance, moisture resistance and antifouling properties can be obtained for a long period of time. The silane coupling layer can be formed by using dipping or the like in addition to the above-described CVD and ALD, for example.

  On the other hand, a water repellent layer is not formed on the side surface of the polarizing plate 1. More specifically, the water repellent layer is not formed on the side surface of the polarizing plate 1, and the transparent substrate 2 is exposed. Therefore, the side surface of the polarizing plate 1 has hydrophilicity. Here, the side surface of the polarizing plate 1 means a surface extending in the thickness direction of the polarizing plate 1 and constitutes the side surface of the outer peripheral end portion of the polarizing plate 1.

  Since the coating layer such as the water repellent layer is not formed on the side surface of the polarizing plate 1 as described above, the protective film such as a conventional polarizing plate can be prevented from falling off at the time of mounting to an optical device, for example. The handling of the board can be facilitated. The side surface of the polarizing plate 1 is in a state where the transparent substrate 2 is exposed. However, since the side surface of the polarizing plate 1 is located at the outer peripheral end, the polarizing plate 1 in which light enters and exits even when in use is used. Compared to the central part, the temperature is not so high, and it can be said that problems of oxidation and corrosion do not easily occur.

  Further, identification markings are provided on the side surfaces of the polarizing plate 1. Specifically, product information is printed using a laser marking, a marking pen, a diamond cutter, or the like. As described above, since the polarizing plate 1 according to the present embodiment has no water repellent layer 4 formed on the side surface and the transparent substrate 2 is exposed, the side surface has hydrophilicity, such as a marking pen. The ink by is easy to get used to and can be marked reliably. In addition, since the layer covering the side surface is not formed, the protective film or the like is not peeled off and causes dust when printing is performed with a laser marking or a diamond cutter. Therefore, according to this embodiment, marking can be performed reliably and the polarizing plate 1 can be easily and reliably identified.

[Production Method of Polarizing Plate 1]
(First manufacturing method)
The first manufacturing method of the polarizing plate 1 includes a lattice-shaped convex portion forming step, a water repellent layer forming step, and a cutting step. Hereafter, each process is demonstrated in detail with reference to FIG. 3A-FIG. 3C.
Here, FIG. 3A to FIG. 3C are diagrams for explaining a method of manufacturing the polarizing plate 1 according to the present embodiment.

  First, in the grid-like convex forming process, on one surface side of the transparent substrate 2 larger than the use size of the polarizing plate 1, the grid-like convex extending in a predetermined direction with a pitch shorter than the wavelength of light in the use band. 3 is formed. That is, in the first manufacturing method, the grid-like convex portions 3 are formed on the large transparent substrate 2 larger than the size of the polarizing plate 1 used.

  The lattice-shaped convex portion forming step includes, for example, a reflective layer forming step, a dielectric layer forming step, an absorbing layer forming step, and an etching step. As described above, the dielectric layer forming step and the absorbing layer forming step may be integrated to integrally form the dielectric layer and the absorbing layer.

  In the reflective layer forming step, a reflective layer is formed on the transparent substrate 2. In the dielectric layer forming step, a dielectric layer is formed on the reflective layer formed in the reflective layer forming step. In the absorbing layer forming step, an absorbing layer is formed on the dielectric layer formed in the dielectric layer forming step. In each of these layer forming steps, each layer can be formed by, for example, sputtering or vapor deposition.

  In the etching process, by selectively etching the laminated body formed through the above-described respective layer forming processes, the lattice-shaped protrusions 3 arranged on the transparent substrate 2 at a pitch shorter than the wavelength of light in the use band are formed. Form. Specifically, a one-dimensional lattice-like mask pattern is formed by, for example, a photolithography method or a nanoimprint method. And the lattice-like convex part 3 arranged on the transparent substrate 2 with the pitch shorter than the wavelength of the light of a use zone | band is formed by selectively etching the said laminated body. As an etching method, for example, a dry etching method using an etching gas corresponding to an object to be etched is used.

  In the water repellent layer forming step, as shown in FIG. 3A, the water repellent layer 4 is formed so as to cover one surface of the large transparent substrate 100A on which the lattice-like convex portions 3 are formed. The water repellent layer forming step includes, for example, a silica layer forming step and a silane coupling layer forming step.

  In the silica layer forming step, a silica layer made of silica is formed so as to cover one surface of the large transparent substrate 100A on which the lattice-shaped convex portions 3 are formed. Specifically, the silica layer is formed by using, for example, the above-described CVD or ALD. At this time, the silica layer is formed so as to cover not only one surface of the transparent substrate 100A but also the other surface in terms of the method for forming the silica layer.

  In the silane coupling layer forming step, as shown in FIG. 3A, a silane coupling layer made of the silane coupling agent 9 is formed on the surface of the silica layer formed by the silica layer forming step. Specifically, for example, a silane coupling layer is formed by using dipping or the like in addition to the above-described CVD and ALD. At this time, the silane coupling layer is formed so as to cover not only one surface of the transparent substrate 100A but also the entire other surface due to the molding method of the silane coupling layer.

  In the cutting step, as shown in FIG. 3B, the large transparent substrate 100 </ b> B on which the water-repellent layer 4 is formed is cut into a use size of the polarizing plate 1. Specifically, first, a dividing groove (crack) is formed on the surface of the transparent substrate 100B by, for example, scribing using the scriber 8 or the like. Next, the transparent substrate 100B is divided (breaked) into individual pieces along the formed dividing grooves to obtain a desired size.

As described above, in the first manufacturing method, since a large transparent substrate is used, the transparent substrate 100B is cut into a desired size suitable for the size of the liquid crystal panel or the like by this process. At this time, since the transparent substrate 100B on which the water repellent layer 4 is formed is cut, the transparent substrate is exposed on the side surface of the polarizing plate 1 obtained by cutting without the water repellent layer.
Thus, the polarizing plate 1 having a desired size as shown in FIG. 3C and having the transparent substrate exposed on the side surface is manufactured.

(Second manufacturing method)
The above-described second manufacturing method of the polarizing plate 1 includes a grid-like convex portion forming step, a water repellent layer forming step, and a removing step. Hereinafter, each step will be described in detail.

  In the grid-like convex portion forming step, the grid-like convex portion extending in a predetermined direction at a pitch shorter than the wavelength of light in the use band on one surface side of the transparent substrate having the same size as the use size of the polarizing plate 1 3 is formed. That is, in the second manufacturing method, the grid-like convex portions 3 are formed on a small-sized transparent substrate having a size equivalent to the size of the polarizing plate 1 used. In addition, the formation procedure itself of the grid-like convex portion 3 is the same as that of the first manufacturing method. A convex portion 3 is formed.

  In the water-repellent layer forming step, the water-repellent layer 4 is formed so as to cover one surface of the small-sized transparent substrate on which the lattice-like convex portions 3 are formed. This water repellent layer forming step is the same as the water repellent layer forming step in the first manufacturing method. At this time, the water-repellent layer 4 is formed so as to cover not only one surface of the transparent substrate but also the other surface due to the method of forming the water-repellent layer 4.

In the removing step, the water repellent layer 4 formed on the side surface of the transparent substrate is removed by etching. As described above, in the second manufacturing method, a small transparent substrate having a size equivalent to the size of the polarizing plate 1 used is used, so that the cutting step as in the first manufacturing method is unnecessary. As described above, the water-repellent layer 4 is also formed on the side surface of the polarizing plate 1, and the water-repellent layer 4 formed on the side surface of the polarizing plate 1 is removed by this step. Specifically, the side water-repellent layer 4 is removed by desired etching or the like.
Thus, the polarizing plate 1 with the transparent substrate exposed on the side surface is manufactured.

[Optical equipment]
The optical apparatus according to this embodiment includes the polarizing plate 1 described above. Examples of the optical device include a liquid crystal projector, a head-up display, and a digital camera. Since the polarizing plate 1 according to the present embodiment is an inorganic polarizing plate that is superior in heat resistance compared to an organic polarizing plate, it is suitable for applications such as liquid crystal projectors and head-up displays that require heat resistance.

  For example, the polarizing plate 1 is fitted into a mounting frame (fixed frame) provided inside an optical apparatus such as a liquid crystal projector so that the mounting frame comes into contact with the side surface in a vertically placed state. Then, for example, an adhesive is supplied between the mounting frame and the side surface of the polarizing plate 1, whereby the polarizing plate 1 is fixed to the mounting frame. At this time, since the transparent substrate 2 is exposed and hydrophilic, the side surface of the polarizing plate 1 according to the present embodiment is easy to become familiar with the adhesive, and has high adhesive strength and can be firmly fixed to the mounting frame. . Further, since there is no water repellent layer on the side surface, it is possible to prevent the adhesive from flowing into the center of the polarizing plate 1 due to the capillary action of the grid, and the productivity of the optical apparatus can be improved by improving the workability of the bonding work.

  In addition, this invention is not limited to the said embodiment, The deformation | transformation and improvement in the range which can achieve the objective of this invention are included in this invention.

  In the said embodiment, although the polarizing plate 1 is an absorption-type polarizing plate and the grid | lattice-like convex part 3 is comprised by the laminated body of a reflective layer, a dielectric material layer, and an absorption layer, it is not limited to this. For example, the dielectric layer and the absorption layer may be integrated. Alternatively, the lattice-shaped convex portion may be formed of a reflective layer, and the polarizing plate 1 may be a reflective polarizing plate.

  Moreover, in the said embodiment, although the water-repellent layer 4 is formed also in the other surface (surface on the opposite side to the surface in which the lattice-shaped convex part 3 was formed) of the polarizing plate 1, it is not limited to this. The water repellent layer 4 only needs to be formed on at least one surface of the polarizing plate 1 (the surface on which the lattice-shaped convex portions 3 are formed).

  Moreover, in the said embodiment, although the water repellent layer 4 is formed so that the whole one surface of the polarizing plate 1 including the inside of each groove | channel between the adjacent grid | lattice-shaped convex parts 3 may be covered, it is not limited to this. The water repellent layer 4 should just be arrange | positioned so that the surface of the lattice-like convex part 3 may be covered at least.

DESCRIPTION OF SYMBOLS 1 Polarizing plate 2 Transparent substrate 3 Grid-shaped convex part 4 Water repellent layer

Claims (1)

A method of manufacturing a polarizing plate having a wire grid structure,
Forming a grid-like convex part that forms a grid-like convex part extending in a predetermined direction at a pitch shorter than the wavelength of light in the use band on one surface side of a transparent substrate having a size equivalent to the use size of the polarizing plate Process,
A water-repellent layer forming step of forming a water-repellent layer covering the surface of the transparent substrate and the surface of the grid-like convex portion on one surface side of the transparent substrate;
And a removing step of removing the water-repellent layer formed on the side surface of the transparent substrate by etching.

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