JP2014112137A - Method for manufacturing polarizing element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a polarizing element excellent in optical characteristics.SOLUTION: The method for manufacturing a polarizing element 100 includes steps of: forming a metal composite film 11 by depositing particles 11b of a second metal on a transparent substrate 10 while depositing particles 11a of a first metal on the transparent substrate 10; selectively etching the first metal; forming a protective film 13 on the metal composite film where the first metal is etched; and forming particles 12c comprising the second metal and having shape anisotropy by stretching the transparent substrate 10 at a temperature where the transparent substrate 10 softens.

Description

  The present invention relates to a method for manufacturing a polarizing element.

  As one type of polarizing element, polarizing glass is known. Since the polarizing glass can be composed only of an inorganic material, the deterioration with respect to light is remarkably small as compared with a polarizing plate containing an organic material. Therefore, it has been attracting attention as an effective optical device in a liquid crystal projector whose brightness has been increasing in recent years.

As general polarizing glass, what was described in patent document 1 is well-known, and the manufacturing method is as follows.
(1) A glass product having a desired shape is produced from a composition containing at least one halide and silver selected from the group of chloride, bromide, and iodide.
(2) A temperature above the strain point, but not higher than about 50 ° C. from the glass softening point, for a period of time sufficient to cause the glass product to produce AgCl, AgBr, or AgI crystals in the glass product. To produce a crystal-containing product.
(3) The crystal-containing product is stretched under stress at a temperature above the annealing point but below the temperature at which the glass exhibits a viscosity of about 108 poise so that the crystal is stretched to an aspect ratio of at least 5: 1. .
(4) A reducing atmosphere at a temperature higher than about 250 ° C., but not higher than about 25 ° C. from the annealing point of the glass, for a period sufficient to develop a chemically reduced surface layer on the product. To be exposed to. Thereby, at least a part of the extended silver halide grains is reduced to silver element.

JP 56-169140 A

  In the production method described in Patent Document 1, metal halides are uniformly deposited in glass products. However, since only the metal halide on the surface of the glass product can be reduced in the reduction process, the metal halide remains in the central portion in the thickness direction of the glass product. Therefore, the transmittance of the polarizing element is reduced.

  The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a method for manufacturing a polarizing element having excellent optical characteristics.

  The method for producing a polarizing element of the present invention comprises a step of forming a metal composite film by depositing second metal particles on the transparent substrate while depositing the first metal particles on the transparent substrate; Selectively etching the first metal, forming a protective film on the metal composite film etched with the first metal, and the transparent substrate at a temperature at which the transparent substrate is softened. Forming a particle having shape anisotropy made of the second metal.

  The first metal particles and the second metal particles are adhered to the surface of the transparent substrate by depositing the second metal particles on the transparent substrate while the first metal particles are adhered on the transparent substrate. A metal composite film mixed with each other can be formed. Then, by selectively removing the first metal from the metal composite film, it is possible to obtain a transparent substrate in which the particles of the second metal are arranged on the surface of the transparent substrate with a substantially uniform size and interval. . Thereafter, by stretching this transparent substrate, particles having shape anisotropy made of the second metal are arranged at substantially uniform sizes and intervals, and a polarizing element having excellent optical characteristics can be manufactured.

  Further, since the second metal particles are distributed only on the surface of the transparent substrate, even if the second metal is halogenated during the step of etching the first metal, the reduction is performed. By performing the treatment, all of the second metal halogenated is reduced. Therefore, the transmittance of the polarizing element is not lowered due to the remaining metal halide.

  In the step of forming the metal composite film, the density of the particles having shape anisotropy made of the second metal can be adjusted by changing the ratio of the first metal to the second metal. . As a result, since the interval between the particles having shape anisotropy made of the second metal can be arbitrarily changed, a polarizing element in which the light transmittance and the absorptance are arbitrarily adjusted can be manufactured.

In the step of selectively etching the first metal, the first metal can be etched in a plasma environment in which a halogen gas is excited. In this case, the second metal is preferably halogenated.
According to this manufacturing method, since the melting point of the second metal is lowered by being halogenated, the temperature and tensile stress required for stretching the transparent substrate can be reduced.
In this manufacturing method, it is preferable to use a film forming method in a non-plasma environment as a method for forming the protective film. This is to suppress the reduction of the halogenated second metal.

In the step of forming the metal composite film, a mixture or alloy of the first metal and the second metal may be used as a vacuum deposition source.
According to this manufacturing method, the first metal particles and the second metal particles adhere to the transparent substrate in accordance with the ratio of the mixture of the first metal and the second metal. A metal composite film in which the ratio of the first metal and the second metal is substantially uniform can be formed.

  The method for producing a polarizing element of the present invention comprises a step of forming a metal composite film by depositing metal compound particles on a transparent substrate while depositing metal particles on the transparent substrate; Selectively etching, forming a protective film on the metal composite film etched with the metal compound, and stretching the transparent substrate at a temperature at which the transparent substrate is softened. Forming particles having shape anisotropy.

  A metal composite film in which metal particles and metal compound particles are mixed with each other on the surface of the transparent substrate by attaching metal compound particles on the transparent substrate while attaching metal particles on the transparent substrate. Can be formed. Then, by selectively removing the metal compound from the metal composite film, a transparent substrate in which metal particles are arranged on the surface of the transparent substrate with a substantially uniform size and interval can be obtained. Thereafter, by stretching this transparent substrate, particles having shape anisotropy made of metal are arranged at substantially uniform sizes and intervals, and a polarizing element having excellent optical characteristics can be manufactured.

  Further, since the metal particles are distributed only on the surface of the transparent substrate, even when the metal is halogenated during the etching process of the metal compound, it is halogenated by performing the reduction treatment. All metals are reduced. Therefore, the transmittance of the polarizing element is not lowered due to the remaining metal halide.

  The two particles forming the metal composite film are a metal particle and a metal compound particle. Therefore, compared to metals, the properties of each particle are greatly different, and the conditions for etching are often different. Therefore, it is possible to etch only the metal compound from the metal composite film with higher accuracy, and it is possible to obtain a transparent substrate in which metal particles are arranged on the surface with a more uniform size and interval. Thereafter, by stretching the transparent substrate, metal particles having shape anisotropy are arranged at uniform sizes and intervals, and a polarizing element having excellent optical characteristics can be manufactured.

  In the step of selectively etching the metal compound, the metal compound may be etched in a plasma environment in which a halogen gas is excited. In this case, the metal is preferably halogenated.

  The manufacturing method of the polarizing element of the present invention includes a step of forming a metal composite film by attaching metal compound particles made of a transparent material on the transparent substrate while attaching metal particles on the transparent substrate; Forming a protective film on the metal composite film, and forming the particles having shape anisotropy made of the metal by stretching the transparent substrate at a temperature at which the transparent substrate is softened. Have.

  According to this manufacturing method, the portion of the metal composite film to which the metal compound particles are attached becomes transparent, and thus the optical characteristics of the manufactured polarizing element are not affected without removing the metal compound particles. . Therefore, it is not necessary to selectively remove the metal compound from the metal composite film, and the labor for performing the etching process can be saved.

  Moreover, in the manufacturing method of the polarizing element of this invention, it can also have the process by which the said metal is halogenated.

According to these manufacturing methods, since the melting point of the metal is lowered by being halogenated, the temperature and tensile stress required for stretching the transparent substrate can be reduced.
In these manufacturing methods, it is preferable to use a film forming method in a non-plasma environment as a method for forming the protective film. This is to suppress the reduction of the halogenated metal.

  In the step of forming the metal composite film, the density of the particles made of the metal having the shape anisotropy can be adjusted by changing the ratio of the metal and the metal compound. As a result, since the interval between the particles made of metal having shape anisotropy can be arbitrarily changed, a polarizing element in which the light transmittance and absorptance are arbitrarily adjusted can be manufactured.

The figure which shows the manufacturing method of the polarizing element of 1st Embodiment. The figure which shows the formation method of the metal composite film of 1st Embodiment. The figure which shows the case where the ratio of the particle | grains of the 1st metal and 2nd metal adhering to a transparent substrate is changed. The figure which shows the planar structure of a transparent substrate. The figure which shows the manufacturing method of the polarizing element of 2nd Embodiment. The figure which shows the formation method of the metal composite film of 2nd Embodiment. The figure which shows the manufacturing method of the polarizing element of the modification of 2nd Embodiment. The figure which shows the verification experiment result of the formation process of the metal composite film of 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

[First Embodiment]
First, the first embodiment will be described.
FIG. 1 is a diagram showing a method for manufacturing a polarizing element of this embodiment.

As shown in FIG. 1, the manufacturing method of the polarizing element of this embodiment includes a metal composite film forming step S11, an etching step S12, a protective film forming step S13, a stretching step S14, and a reducing step S15. .
The following detailed description of each step exemplifies a case where the first metal shown in the latter stage is Al and the second metal is Ag.

In the metal composite film forming step S11, as shown in FIG. 1A, the first metal particles 11a and the second metal particles 11b are attached on the surface of the transparent substrate 10 to form the metal composite film 11. It is a process to do.
The transparent substrate 10 is not particularly limited, and any known transparent substrate can be used. In the manufacturing method of the polarizing element of this embodiment, it is not necessary to deposit a metal halide in the transparent substrate or introduce metal ions into the surface of the transparent substrate by ion exchange, thereby forming the metal composite film 11. This is because it may be possible. Specifically, various transparent substrates, such as quartz glass, soda lime glass, sapphire glass, borosilicate glass, and aluminoborosilicate glass, can be used.

  The metal composite film 11 includes a plurality of first metal particles 11a and a plurality of second metal particles 11b. The first metal particles 11a are particles formed by aggregating a plurality of metal particles including the first metal flying from the vapor deposition source onto the surface of the transparent substrate 10 in the metal composite film forming step S11 described later. is there. The second metal particle 11b is a particle formed by aggregating a plurality of metal particles including the second metal flying from the vapor deposition source onto the surface of the transparent substrate 10 in the metal composite film forming step S11 described later. is there. Each of the plurality of first metal particles 11a has a minute and substantially uniform size, and each of the plurality of second metal particles 11b has a minute and substantially uniform size. The plurality of first metal particles 11 a and the plurality of second metal particles 11 b are attached to the surface of the transparent substrate 10 so as to be mixed with each other on the surface of the transparent substrate 10. The surface of the transparent substrate 10 on which the metal composite film 11 is formed is hardly exposed, and a plurality of first metal particles 11a and a plurality of second metal particles 11b are spread on the same plane. .

  The metal composite film 11 is preferably a substantially one-layer film in which the first metal particles 11a and the second metal particles 11b are not stacked in the film thickness direction. When the second metal particles 11b are stacked on the first metal particles 11a attached on the surface of the transparent substrate 10, the first metal cannot be completely removed in the subsequent etching step S12. This is because of this. Even if the first metal is completely removed, it is impossible to predict in what state the second metal particles 11b will remain on the surface of the transparent substrate 10, and the shape and distribution will not be uniform. This is also possible.

  In the metal composite film forming step S <b> 11, a large number of metal particles attached on the surface of the transparent substrate 10 become larger by agglomerating metal particles containing one metal. However, by attaching a plurality of metal particles containing one metal on the surface of the transparent substrate 10 while attaching a plurality of metal particles containing one metal on the surface of the transparent substrate 10, the one metal is contained. Metal particle growth is inhibited by metal particles containing other metals that also aggregate. As a result, the size of the aggregated metal particles is suppressed to a minute size, and the aggregation of the metal particles stops when there is no region where the surface of the transparent substrate 10 is exposed. As a result, a metal in which the first metal particles 11a and the second metal particles 11b each having a minute and substantially uniform size (about 10 to 40 nm) are spread on the surface of the transparent substrate 10 at substantially uniform intervals. A composite film 11 is formed.

  In addition, when a plurality of metal particles including one metal and a plurality of metal particles including another metal are sequentially attached, the plurality of metal particles previously attached aggregate to form a film, and are attached later. The plurality of metal particles to be deposited are stacked and attached on the film composed of the plurality of metal particles previously attached. Therefore, the metal composite film 11 in which the plurality of first metal particles 11 a and the plurality of second metal particles 11 b are mixed with each other on the surface of the transparent substrate 10 cannot be formed.

  The method for forming the metal composite film 11 is not particularly limited as long as it satisfies the above conditions, and may be either a gas phase method or a liquid phase method. When using a vapor phase method, either physical vapor deposition or chemical vapor deposition may be used. As the physical vapor deposition method, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like can be selected.

FIG. 2 is a diagram showing a metal composite film forming method in the case of using a vacuum deposition method in the metal composite film forming step S11.
As shown in FIG. 2A, a transparent substrate 10, a vapor deposition source 21a made of a first metal, and a vapor deposition source 21b made of a second metal are installed in a vacuum chamber 200. Further, instead of arranging the vapor deposition source 21a and the vapor deposition source 21b, as shown in FIG. 2B, a vapor deposition source 21c made of a mixture or alloy of the first metal and the second metal may be arranged. . Further, as shown in each drawing of FIG. 2, the transparent substrate 10 is fixed to the substrate holder 20. Each vapor deposition source is installed at a position facing the surface of the transparent substrate 10 on which the metal composite film 11 is formed.

  In order to form the metal composite film 11 in a state where the plurality of first metal particles 11a and the plurality of second metal particles 11b are substantially uniformly mixed with each other on the surface of the transparent substrate 10, each deposition is performed. It is preferable that the source is installed at a position at a sufficient distance from the transparent substrate 10.

  The metal composite film 11 is formed by heating and evaporating a vapor deposition source in a vacuum chamber 200 whose inside is evacuated by a vacuum pump to cause metal particles to fly and adhere to the surface of the transparent substrate 10.

  The method for heating the vapor deposition source is not particularly limited as long as the selected vapor deposition source can be evaporated in a vacuum state.

  When the metal composite film 11 is formed by the vacuum evaporation method, as shown in FIG. 2A, the vapor deposition source 21a made of the first metal and the vapor deposition source 21b made of the second metal are simultaneously heated to form the transparent substrate 10. A simultaneous film-forming method in which the first metal particles 11a and the second metal particles 11b are deposited on the surface of the substrate, and a mixture of the first metal and the second metal, as shown in FIG. A mixture film forming method using an evaporation source 21c made of an alloy can be selected.

  In the case of using the simultaneous film forming method shown in FIG. 2A as the metal composite film forming method, the amount of heat applied to the vapor deposition source 21a made of the first metal and the vapor deposition source 21b made of the second metal is respectively determined. By changing the amount, the amount of metal particles evaporated per unit time can be changed between the first metal and the second metal. That is, when the heating amount of the vapor deposition source is increased, the amount of metal particles that evaporate also increases, and when the heating amount of the vapor deposition source is decreased, the amount of metal particles that evaporate also decreases. Thereby, the ratio of the 1st metal and 2nd metal adhering to the surface of the transparent substrate 10 can be adjusted.

  In the case of using the mixture film forming method shown in FIG. 2B as the metal composite film forming method, the mixing ratio or alloy ratio of the vapor deposition source 21c made of the mixture or alloy of the first metal and the second metal is arbitrarily set. By selecting the above, it is possible to change the ratio of the amount of the metal particles including the first metal and the metal particles including the second metal that are evaporated per unit time. Thereby, the ratio of the 1st metal and 2nd metal adhering to the surface of the transparent substrate 10 can be adjusted.

  FIG. 3 is a diagram schematically showing a case where the ratio of the first metal and the second metal adhering to the surface of the transparent substrate 10 is changed in the metal composite film forming step S11. When the ratio of the first metal composed of Al and the second metal composed of Ag adhering to the surface of the transparent substrate 10 is Al: Ag = 1: 1 (FIG. 3A), The case where Al: Ag = 3: 1 (FIG. 3B) is shown.

  For example, when the metal composite film 11 as shown in FIG. 3B is formed by using the simultaneous film forming method shown in FIG. 2A, evaporation is performed from the vapor deposition source 21a (Al) made of the first metal. The amount of heat applied to the first metal deposition source 21a can be increased so that the amount of the metal particles to be generated is three times larger than the amount of metal particles evaporated from the second metal deposition source 21b (Ag). That's fine.

  For example, when the metal composite film 11 as shown in FIG. 3B is formed using the mixture film forming method shown in FIG. 2B, the first metal (Al) and the second metal ( A vapor deposition source 21c made of a mixture or alloy of the first metal and the second metal such that the mixing ratio or alloy ratio of Ag) is 3: 1 may be used.

Next, in the etching step S12, as shown in FIG. 1B, the first metal (Al) is selectively removed from the metal composite film 11 (selectively etched).
The etching method is not particularly limited as long as the first metal contained in the metal composite film 11 can be selectively removed, and either dry etching or wet etching can be used.

In the present embodiment, plasma etching in which the metal composite film 11 is exposed to plasma of a Cl-based gas (Cl ₂ , BCl _3, etc.) can be selected as dry etching. Thereby, the first metal made of Al is vaporized as AlClx, and therefore can be removed from the metal composite film 11. On the other hand, the second metal made of Ag becomes AgClx and remains on the surface of the transparent substrate 10. Therefore, the first metal made of Al can be selectively removed by the etching method. Further, the second metal composed of Ag is halogenated to become AgClx, whereby the heating temperature of the transparent substrate 10 required in the subsequent stretching step S14 can be lowered. Therefore, in the etching step S12, it is preferable to select an etching method that can halogenate the second metal simultaneously with the removal of the first metal.

  FIG. 4A is a plan view showing the surface of the transparent substrate 10 after the etching step S12. As shown in FIG. 4A, the first metal is selectively removed by the etching step S12, and a region 10a where the surface of the transparent substrate 10 is exposed is formed. As a result, the plurality of island-shaped particles 12a, which are halides of the second metal, remain on the surface of the transparent substrate 10, and the island-shaped film 12 is formed.

  The metal composite film 11 is composed of the first metal particles 11a and the second metal particles 11b having a minute and substantially uniform size distributed substantially uniformly on the same plane. Therefore, the first metal is selectively used. The island-like film 12 formed by the removal has excellent uniformity in the size and distribution of the constituent particles (island-like particles 12a).

  In the metal composite film forming step S <b> 11, by changing the ratio of the first metal and the second metal adhering to the surface of the transparent substrate 10, the island shape disposed on the surface of the transparent substrate 10 via the region 10 a. The distribution density of the particles 12a can be adjusted. That is, the larger the proportion of the first metal, the smaller the number of second metal particles 11b remaining on the surface of the transparent substrate 10 without being removed in the etching step S12. As a result, the distribution density of the shape anisotropic particles 12b formed in the subsequent stretching step S14 can be adjusted.

Next, in protective film formation process S13, as shown in FIG.1 (c), the protective film 13 is formed so that the island-shaped film 12 may be covered.
The material of the protective film 13 is not particularly limited as long as it can form a transparent film and can withstand the heating temperature in the subsequent stretching step S14. For example, silicon oxide, silicon nitride, titanium oxide, zirconium oxide, or the like can be used. When glass is selected as the transparent substrate 10, it is preferable to use silicon oxide having a common component.

  The method for forming the protective film 13 is not particularly limited as long as it is a method capable of forming the above-described film. However, in order to prevent the island-like particles 12a made of AgClx formed in the etching step S12 from being reduced, A film forming method that does not expose the film 12 to plasma (film forming method in a non-plasma environment) is preferable. As a film formation method in a non-plasma environment, either a vapor phase method or a liquid phase method can be used. If the island-shaped particles 12a made of metal halide are not reduced, a film forming method in a plasma environment may be used.

  When the protective film 13 is formed by a vapor phase method in a non-plasma environment, either physical vapor deposition or chemical vapor deposition may be used. An example of the physical vapor deposition method is a vacuum vapor deposition method. As the vacuum vapor deposition method, either a heat vapor deposition method or an electron vapor deposition method can be used. As the chemical vapor deposition method, thermal CVD or photo CVD can be used.

  When the protective film 13 is formed by a liquid phase method in a non-plasma environment, for example, an SOG (Spin On Glass) material containing a silicon-based polymer compound such as polysilazane or polyhydridosilane is applied to a spin coat method, a spray coat method, a slit. A coating method, a roll coating method, a die coating method, a dip coating method, a liquid-to-jet method, or the like can be applied, and a method of firing this can be used.

  Although the film thickness of the protective film 13 is not specifically limited, For example, when forming the protective film 13 with a silicon oxide film, the range of 100 nm-500 nm is preferable. When the protective film 13 is too thin, the protective film 13 may be broken in the subsequent stretching step S14, and the island-shaped particles 12a may be exposed. On the other hand, the thicker the protective film 13, the greater the internal stress generated in the protective film, causing the protective film itself to peel off. Therefore, the film thickness of the protective film 13 should just be a range which can obtain protective performance.

  Next, in the stretching step S14, as shown in FIG. 1D, at a temperature at which the transparent substrate 10 is softened, the transparent substrate 10 is parallel to the surface of the transparent substrate 10 to which the island-shaped particles 12a are attached. Is stretched (stretched). The stretching method may be a stretching process in which the transparent substrate 10 is pulled in a direction parallel to the surface, or may be a rolling process in which the transparent substrate 10 is thinly stretched by pressure. The heating temperature in the stretching step S14 is set according to the material of the transparent substrate 10 and the island-shaped particles 12a. In the case of the present embodiment, the temperature is set so that the transparent substrate 10 can be softened without being dissolved and the island-shaped particles 12a can be extended.

  By the stretching step S14, the transparent substrate 10 is stretched in the stretching direction and processed to be thin. In addition, the island-shaped particles 12a on the surface of the transparent substrate 10 are also stretched in the stretching direction, and as shown in FIG. The shape anisotropic particles 12b are obtained. The shape anisotropic particles 12b have shape anisotropy and have an elongated shape with an aspect ratio of, for example, 5 or more. For example, the width is about 3 to 10 nm and the length is about 15 to 50 nm. Further, as shown in FIG. 1D, the protective film 13 covering the island-shaped particles 12a is also thinly stretched together with the transparent substrate 10, and becomes a protective film covering the shape anisotropic particles 12b.

  In the region between the plurality of shape anisotropic particles 12b formed by the stretching step S14, the region 10a shown in FIG. 4A is extended to form an elongated slit-shaped region 10b. The size of the slit-shaped region 10b varies depending on the formation density of the island-shaped particles 12a, but is about 3 to 10 nm in width and about 15 to 50 nm in length.

  Next, in the reduction step S15, as shown in FIG. 1E, the shape anisotropic particles 12b made of AgClx formed on the surface of the transparent substrate 10 are heat-treated in a reducing atmosphere to form Ag. To form shape anisotropic metal particles 12c. The shape anisotropic metal particles 12c have the same shape anisotropy as the shape anisotropic particles 12b. For a period sufficient to develop a chemically reduced surface layer, the glass is exposed to a reducing atmosphere at a temperature higher than about 250 ° C., but not higher than about 25 ° C. from the glass annealing point. In the present embodiment, since the shape anisotropic particles 12b are covered with the protective film 13 on the surface of the transparent substrate 10, the reduction heat treatment is performed for a time period in which a reduced surface layer having a thickness equal to or larger than the thickness of the protective film 13 is generated. Just do it.

It is efficient to use hydrogen gas as the reducing atmosphere. Other known reducing atmospheres such as ammonia cracked gas, a mixture of CO ₂ and CO may be used.

  Through the above steps, a large number of shape anisotropic metal particles 12c oriented in one direction within the substrate surface are arranged on the surface of the transparent substrate 10 via the slit-shaped region 10b (see FIG. 4B). The polarizing element 100 can be manufactured.

  In the polarizing element 100 manufactured by the manufacturing method of the present embodiment, the shape anisotropic metal particles 12c having a width narrower than the wavelength of visible light are arranged at a narrow pitch, whereby transmitted light is transmitted in a predetermined vibration direction. It can be used as an optical element having a function of separating into linearly polarized light.

In addition, in the conventional polarizing glass, the arrangement density of the metal particles having shape anisotropy was about 20 or less per 1 μm ^3, so in order to obtain high polarization separation characteristics, the metal particles having shape anisotropy were used. It was necessary to distribute widely in the thickness direction of the glass substrate. On the other hand, in the polarizing element of this embodiment, since the shape anisotropic metal particles 12c are arranged at a high density on the surface of the transparent substrate 10, the transparent substrate 10 having an arbitrary thickness can be used. It is also easy to make a thin polarizing element.

  According to the manufacturing method of the present embodiment described in detail above, in the metal composite film forming step S11, while the plurality of first metal particles 11a are adhered on the surface of the transparent substrate 10, the second metal By attaching the particles 11b on the surface of the transparent substrate 10, a plurality of first metal particles 11a and a plurality of second metal particles 11b having a minute and substantially uniform size are mutually connected on the same plane. A metal composite film 11 is formed which is distributed and spread almost uniformly so as to be mixed. Then, in the etching step S12, the first metal is selectively removed, and the island-like particles 12a made of the halide of the second metal are distributed substantially uniformly and in an island shape on the surface of the transparent substrate 10. 12 is formed. Thereafter, the island-shaped particles 12a become the shape anisotropic metal particles 12c through the protective film forming step S13, the stretching step S14, and the reducing step S15. As a result, the plurality of shape-anisotropic metal particles 12c are substantially uniform in size and are arranged at high density on the surface of the transparent substrate 10 at substantially uniform intervals. It is possible to easily manufacture a uniform polarizing element.

  Further, according to the manufacturing method of the present embodiment, since the shape anisotropic particles 12b are formed on the surface of the transparent substrate 10, the reduction surface layer having a thickness equal to or larger than the thickness of the protective film 13 is generated in the reduction step S15. By doing so, the shape anisotropic particles 12b made of the halide of the second metal can be reliably reduced. Therefore, the transmittance does not decrease due to the metal halide remaining inside the glass substrate unlike the conventional polarizing glass.

  Further, according to the manufacturing method of the present embodiment, in the metal composite film forming step S11, the two kinds of metal particles are changed by changing the ratio of the first metal and the second metal attached to the surface of the transparent substrate 10. The metal composite film 11 distributed substantially uniformly at a desired ratio can be formed. Then, in the etching step S12, the first metal is selectively removed, and the island-like particles 12a in which the second metal is halogenated are distributed on the surface of the transparent substrate 10 at a density according to the ratio of the two kinds of metals. Will be. After that, the island-shaped particles 12a become the shape anisotropic metal particles 12c through the protective film forming step S13, the stretching step S14, and the reduction step S15. Therefore, the density of the shape anisotropic metal particles 12c can be arbitrarily adjusted. it can. As a result, since the size of the slit-shaped region 10b (see FIG. 4B) can be arbitrarily changed, the polarizing element 100 in which the light transmittance and the absorptance are arbitrarily adjusted can be manufactured.

Further, in the present embodiment, by selecting plasma etching using a Cl-based gas (Cl ₂ , BCl _3, etc.) in the etching step S12, the second metal made of Ag is halogenated to become AgClx. The melting point of Ag is about 1000 ° C., whereas the melting point of AgClx is about 450 ° C., so that the island-like particles 12a can be easily elongated as compared with the case where the island-like particles 12a are not halogenated. . Specifically, if the transparent substrate 10 is heated to 600 ° C. to 700 ° C., the island-like particles 12 a can be easily stretched together with the transparent substrate 10.

  As described above, in the present embodiment, since the halogenation of the second metal made of Ag is performed in parallel in the etching step S12, it is not necessary to perform a separate halogenation step, and the manufacturing process can be simplified.

  Further, in the manufacturing method of the present embodiment, when the mixture film forming method shown in FIG. 2B is used, since there is one evaporation source, compared with the simultaneous film forming method shown in FIG. The distribution of the first metal particles 11a and the second metal particles 11b adhering to the surface of the transparent substrate 10 becomes more uniform. Further, when the ratio of the first metal and the second metal to be attached to the surface of the transparent substrate 10 is changed, the mixing ratio or alloy of the vapor deposition source 21c made of a mixture or alloy of the first metal and the second metal. Since it is possible by changing the rate, it is simple.

  In the present embodiment, the following method can be selected.

In the metal composite film forming step S11, the first metal may be Si and the second metal may be Ag or Al. As an etching method, plasma etching using a CF-based gas (CF ₄ , C ₂ F ₆ or the like) as an etching gas can be selected. In this plasma etching process, the first metal becomes SiF _{4 and} vaporizes, and the second metal becomes a halide (AgFx or AlF ₃ ) and remains in the form of islands on the surface of the transparent substrate 10.

  In the etching step S12, for example, when wet etching is used, the second metal constituting the metal composite film 11 may not be halogenated. In such a case, a step of halogenating the second metal (island particles 12a) distributed in an island shape on the surface of the transparent substrate 10 may be performed after the etching step S12. Moreover, you may transfer to the following protective film formation process S13, without halogenating a 2nd metal.

[Second Embodiment]
Next, a second embodiment will be described. In the present embodiment, the same components as those in the above-described embodiment are appropriately denoted by the same reference numerals as those in the above-described embodiment, and the description thereof is simplified or omitted.

  FIG. 5 is a diagram illustrating a method for manufacturing the polarizing element of the present embodiment.

  As shown in FIG. 5, the manufacturing method of the polarizing element of this embodiment includes a metal composite film forming step S21, an etching step S22, a protective film forming step S23, a stretching step S24, and a reducing step S25. .

The metal composite film forming step S21 is a step of forming the metal composite film 51 by attaching the metal compound particles 51a and the metal particles 51b on the surface of the transparent substrate 10, as shown in FIG.
The metal composite film 51 includes a plurality of metal compound particles 51a and a plurality of metal particles 51b. The metal compound particles 51a are particles formed by aggregating a plurality of particles (sputter particles) containing a metal compound flying from the target 61a to the surface of the transparent substrate 10 in the metal composite film forming step S21 described later. The metal particles 51b are particles formed by aggregating a plurality of particles (sputtered particles) containing metal flying from the target 61b onto the surface of the transparent substrate 10 in the metal composite film forming step S21 described later. Each of the plurality of metal compound particles 51a has a minute and substantially uniform size, and each of the plurality of metal particles 51b has a minute and substantially uniform size. The plurality of metal compound particles 51 a and the plurality of metal particles 51 b are attached to the surface of the transparent substrate 10 so as to be mixed with each other on the surface of the transparent substrate 10. The surface of the transparent substrate 10 on which the metal composite film 51 is formed is hardly exposed, and a plurality of metal compound particles 51a and a plurality of metal particles 51b are spread on the same plane.

  The formation method of the metal composite film 51 is not particularly limited as long as it satisfies the same conditions as the formation conditions of the metal composite film 11 described in the first embodiment, and may be either a gas phase method or a liquid phase method. Also good. When using a vapor phase method, either physical vapor deposition or chemical vapor deposition may be used. As the physical vapor deposition method, a vacuum vapor deposition method, a sputtering method, an ion plating method, or the like can be selected.

FIG. 6 is a diagram showing a metal composite film forming method when sputtering is used in the metal composite film forming step S21.
As shown in FIG. 6, a transparent substrate 10, a target 61 a made of a metal compound, and a target 61 b made of metal are installed in a vacuum chamber 600. The transparent substrate 10 is fixed to the substrate holder 60. The target 61 a and the target 61 b are installed at positions facing the surface of the transparent substrate 10 on which the metal composite film 51 is formed, and are respectively fixed to the target holder 62. A high frequency power supply device 63 is connected to each target holder 62.

  A sputtering gas is introduced into a vacuum chamber 600 whose inside is evacuated by a vacuum pump, and a voltage is applied to the target. As a result, plasma is generated, and a plurality of particles ejected from the target 61 a and a plurality of particles ejected from the target 61 b adhere to the surface of the transparent substrate 10 by ions in the plasma. As described above, the plurality of particles including the metal compound ejected from the target 61 a are adhered on the surface of the transparent substrate 10 while the plurality of particles including the metal compound ejected from the target 61 b are adhered to the surface of the transparent substrate 10. By doing so, the metal composite film 51 is formed.

  When the method shown in FIG. 6 is used as the metal composite film forming method, the unit time attached to the transparent substrate 10 is changed by changing the power input from the high frequency power supply device 63 to the target 61a and the power input to the target 61b. The amount of sputtered particles flying from the target 61a and the amount of sputtered particles flying from the target 61b can be changed.

That is, when the electric power input to the target from the high frequency power supply device 63 is increased, the sputtered particles that are ejected increase, so that the sputtered particles that adhere to the transparent substrate 10 per unit time increase.
On the other hand, when the power input to the target from the high-frequency power supply device 63 is lowered, the sputtered particles that are ejected are reduced, so that the sputtered particles adhering to the transparent substrate 10 per unit time are reduced.
Thus, by adjusting the power input to the target 61a from the high frequency power supply device 63 and the power input to the target 61b, the metal compound flying from the target 61a adhering to the surface of the transparent substrate 10 and the target 61b fly. The proportion of metal can be adjusted.

Next, in the etching step S22, the metal compound is selectively removed from the metal composite film 51 as shown in FIG.
The etching method is not particularly limited as long as the metal compound contained in the metal composite film 51 can be selectively removed, and either dry etching or wet etching can be used.

In the case of this embodiment, plasma etching in which the metal composite film 51 is exposed to plasma can be selected as dry etching. For example, since in the case of using SiO ₂ as the metal compound, by exposure to plasma of a CF-based gas _{(CF 4,} C 2 _{F 6,} etc.), a metal compound composed of SiO ₂ is to vaporize become SiF _4, The metal composite film 51 can be removed. On the other hand, for example, when Ag is selected as the metal that is the material of the target 61b, the metal made of Ag becomes AgFx and remains on the surface of the transparent substrate 10.
As a result, the metal compound is selectively removed, and the island-like particles 52a, which are halides of the metal particles 51b, remain in the form of islands on the surface of the transparent substrate 10, and the island-like film 52 is formed.

  Since the metal particles 51b are halogenated, the heating temperature of the transparent substrate 10 required in the subsequent stretching step S24 can be lowered. Therefore, in the etching step S22, it is preferable to select an etching method that can halogenate the metal particles 51b simultaneously with the removal of the metal compound.

  As shown in FIG. 5C, the protective film forming step S23 is the same as the protective film forming step S13 described in the first embodiment. Thereby, the protective film 13 is formed.

  Drawing process S24 is the same as extending process S14 demonstrated in 1st Embodiment, as shown in FIG.5 (d). Thereby, the shape anisotropic particle 52b is formed.

  As shown in FIG. 5E, the reduction step S25 is the same as the stretching step S15 described in the first embodiment. Thereby, the shape anisotropic metal particle 52c is formed.

  Through the above steps, the polarizing element 500 in which a large number of shape anisotropic metal particles 52c oriented in one direction within the substrate surface are arranged on the surface of the transparent substrate 10 through slit-like regions can be manufactured. it can.

  According to this embodiment, the two particles forming the metal composite film 51 are the metal compound particles 51a and the metal particles 51b. Therefore, compared to metals, the properties of each particle are greatly different, and the conditions for etching are often different. Therefore, it is possible to selectively etch the metal compound from the metal composite film 51 with higher accuracy. As a result, on the surface of the transparent substrate 10, an island-like film 52 is formed in which island-like particles 52a made of halogenated metal particles 51b are arranged in an island shape with a more uniform size and interval. Thereafter, the island-shaped particles 52a become the shape anisotropic metal particles 52c through the protective film forming step S23, the stretching step S24, and the reducing step S25. As a result, the shape anisotropic metal particles 52c are substantially uniform in size, and are disposed at a high density at substantially uniform intervals on the surface of the transparent substrate 10, so that the polarizing element 500 having excellent optical characteristics is manufactured. can do.

  In the present embodiment, the following method can be selected.

In the etching step S22, for example, when SiO ₂ is selected as the metal compound and Au is selected as the metal, the metal particles 51b constituting the metal composite film 51 may not be halogenated. In such a case, the process may proceed to the next protective film forming step S23 without halogenating the metal particles 51b.

[Modification of Second Embodiment]
A modification of the second embodiment will be described. This modification shows a case where a transparent material is used as the metal compound.

As shown in FIG. 7, the manufacturing method of the polarizing element in the modification of the present embodiment includes a metal composite film forming step S31, a halogenating step S32, a protective film forming step S33, a stretching step S34, and a reducing step S35. And having.
The detailed description of each step below exemplifies the case where the metal compound is SiO ₂ and the metal is Ag.

  As shown in FIG. 7A, the metal composite film forming step S31 is the same as the metal composite film forming step S21 of the present embodiment. Thereby, the metal composite film 51 is formed.

  In the halogenation step S32, as shown in FIG. 7B, the metal particles 51b are halogenated to form metal halide particles 71a, and the composite film 71 is formed.

In this modification, a method of halogenating the metal particles 51b by exposing the transparent substrate 10 to a gas containing halogen or a halogen compound and bringing the metal composite film 51 into contact with the gas can be used. For example, a Cl-based gas (Cl ₂ , BCl _3, etc.) can be selected as the gas. At this time, the metal particles 51b made of Ag become the metal halide particles 71a made of AgClx.

  As shown in FIG. 7C, the protective film forming step S33 is the same as the protective film forming step S13 described in the first embodiment. Thereby, the protective film 13 is formed.

Here, as the metal compound particles 51a, due to the use of SiO ₂ which is a transparent material, the metal compound particles 51a adhered on the surface of the transparent substrate 10 is integrated with the protective film 13 formed by the same transparent material .
As a result, the metal halide particles 71a are distributed in an island shape on the surface of the transparent substrate 10.

  The stretching step S34 is the same as the stretching step S14 described in the first embodiment, as shown in FIG. Thereby, the shape anisotropic particle 71b is formed.

  As shown in FIG. 7E, the reduction step S35 is the same as the stretching step S15 described in the first embodiment. Thereby, the shape anisotropic metal particle 71c is formed.

  Through the above steps, the polarizing element 700 in which a large number of shape anisotropic metal particles 71c oriented in one direction in the substrate surface are arranged on the surface of the transparent substrate 10 through slit-like regions can be manufactured. it can.

  According to this modification, since the transparent material is used as the metal compound particles 51a attached on the surface of the transparent substrate 10, the attached portion of the metal compound particles 51a is transparent. Therefore, even if the metal compound particles 51a are not removed, the optical characteristics of the manufactured polarizing element 700 are not affected. As a result, it is not necessary to perform an etching process, and labor can be saved.

  In this modification, the following method can be selected.

In the metal composite film forming step S31, the metal compound may be SiO ₂ and the metal may be Al. In this case, as the halogenation method in the halogenation step S32, a method of exposing the metal composite film 51 to a CF-based gas (CF ₄ , C ₂ F ₆ or the like) can be selected. In this halogenation process, the metal particles 51b made of Al become metal halide particles 71a made of AlF ₃ .

In the metal composite film forming step S31, the metal compound may be SiO ₂ and the metal may be Au. In this case, the halogenation step S32 may not be performed.

  In the present modification, a halogenation method in which the metal compound is selectively etched in the halogenation step S32 may be used.

  In the present modification, the halogenation step S32 can be omitted. In that case, since the metal particles 51b attached on the surface of the transparent substrate 10 are not halogenated, the reduction step S35 can also be omitted.

[Verification Experiment of Second Embodiment]
The verification experiment of metal composite film formation process S21 in this embodiment was conducted.
A metal composite film in which the ratio of the metal compound composed of SiO ₂ and the metal composed of Au was SiO ₂ : Au = 2: 1 was formed, and an optical characteristic experiment was performed. The formed film thickness is 276 nm.

FIG. 8 shows the optical characteristics of the metal composite film formed above. Measured values of transmittance, reflectance, and absorptance obtained by experiments and calculated values of absorptance obtained by the FDTD method are shown. When the measured value and the calculated value of the absorptance are compared, it is recognized that there is a peak around 540 nm. Since the wavelength of the plasmon absorption spectrum of Au nanoparticles is about 520 to 570 nm, it is recognized that the metal composite film has optical characteristics peculiar to Au nanoparticles. Therefore, the metal composite film has nano-sized Au metal particles.
From the above, it was confirmed that the metal composite film 51 necessary for manufacturing the polarizing element 500 can be formed by the metal composite film forming step S21 in the present embodiment.

  DESCRIPTION OF SYMBOLS 10 ... Transparent substrate, 11, 51 ... Metal composite film, 11a, 11b, 51b ... Metal particle, 51a ... Metal compound particle, 12c, 52c, 71c ... Shape anisotropic metal particle, 13 ... Protective film, 21c ... Deposition source , 100, 500, 700 ... polarizing elements

Claims (11)

Forming a metal composite film by depositing second metal particles on the transparent substrate while depositing the first metal particles on the transparent substrate;
Selectively etching the first metal;
Forming a protective film on the metal composite film etched with the first metal;
Forming the particles having shape anisotropy made of the second metal by stretching the transparent substrate at a temperature at which the transparent substrate softens;
The manufacturing method of a polarizing element which has these.   The step of forming the metal composite film adjusts the density of particles having shape anisotropy made of the second metal by changing a ratio of the first metal to the second metal. The manufacturing method of the polarizing element of 1.   The method for manufacturing a polarizing element according to claim 1, wherein in the step of selectively etching the first metal, the first metal is etched in a plasma environment in which a halogen gas is excited.   The method for manufacturing a polarizing element according to claim 3, wherein the second metal is halogenated in the step of selectively etching the first metal.   5. The polarizing element according to claim 1, wherein, in the step of forming the metal composite film, a mixture or alloy of the first metal and the second metal is used as an evaporation source for vacuum film formation. Manufacturing method. Forming a metal composite film by depositing metal compound particles on the transparent substrate while depositing metal particles on the transparent substrate;
Selectively etching the metal compound;
Forming a protective film on the metal composite film etched with the metal compound;
Forming the particles having shape anisotropy made of the metal by stretching the transparent substrate at a temperature at which the transparent substrate is softened;
The manufacturing method of a polarizing element which has these.   The method for manufacturing a polarizing element according to claim 6, wherein in the step of selectively etching the metal compound, the metal compound is etched in a plasma environment in which a halogen gas is excited.   The method for manufacturing a polarizing element according to claim 7, wherein the metal is halogenated in the step of selectively etching the metal compound. Forming a metal composite film by adhering metal compound particles made of a transparent material on the transparent substrate while adhering the metal particles on the transparent substrate;
Forming a protective film on the metal composite film;
Forming the particles having shape anisotropy made of the metal by stretching the transparent substrate at a temperature at which the transparent substrate is softened;
The manufacturing method of a polarizing element which has these.   The manufacturing method of the polarizing element of Claim 9 which has the process by which the said metal is halogenated.   11. The density of particles made of the metal having the shape anisotropy is adjusted by changing a ratio of the metal and the metal compound in the step of forming the metal composite film. The manufacturing method of the polarizing element of description.

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