JP2007076347A - Heat resistant light interference reflective structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light interference reflective structure showing excellent heat resistance which has not attained, hitherto and also to provide its molding method by designing a laminated structure comprising at least two kinds of inorganic oxides or inorganic sulfides for its pigmentation sufficient to derive a sharp light reflective spectrum so as to achieve a high reflective function of a designed specific wave length in a visible light range, an UV ray range or an infrared ray range. <P>SOLUTION: Two kinds of materials selected from inorganic oxides and sulfides whose light refractive indexes are different from each other are made to alternately and continuously overlie a substrate in such a thickness as giving transparency by reflecting the desired light wave length. Additionally or alternatively, a peeling-off layer is formed between the laminated layer and the substrate, and the peeling-off layer is removed after molding. By this, the heat resistant light interference reflective structure can be obtained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical interference reflection structure having high heat resistance and a sharp wavelength reflection function.

  Structures that reflect light of a specific wavelength are applied in many fields. In particular, infrared rays have a large heat effect, and if this can be blocked, temperature rise can be suppressed. In addition, if ultraviolet rays are excessively received, the human body may be adversely affected, which may cause deterioration of various materials such as various paints and building materials. Therefore, it is extremely important for many materials to control the influence of infrared rays and ultraviolet rays, and various developments have been made for that purpose. Further, the absorption and reflection of wavelengths in the visible light region function as a colorant as seen in pigments and dyes, and there is a further demand for the development of materials for expressing various colors and textures. The reflective properties of the light interference reflective structure can be controlled by the appropriate design of the optical coating or film used to form it, and can reflect light in a particular wavelength region. The specific color is perceived due to the wavelength absorption and reflection of each material used, but the color development of the light interference reflection structure is basically not based on the light absorption but the light interference phenomenon. Therefore, functions and textures different from those of the conventional object color can be obtained. In recent years, development of materials having such characteristics has been promoted.

  An optical interference reflection structure designed to reflect a specific wavelength has been developed (Patent Document 1), and is a structure that provides a hue change according to an incident angle or a viewpoint angle of light. is there. The optical interference reflection structure in this example has a film structure of a five-layer design, and a first absorption layer, a first dielectric layer, a reflection layer, a second dielectric layer, and a second absorption layer are laminated on a substrate in this order. Yes. The layer is then peeled off from the substrate. These flakes are dispersed in a medium to produce a colored material. The material of the first and second absorption layers is selected from chromium, nickel, palladium, titanium, etc., and the material of the first and second dielectric layers is selected from zinc sulfide, zirconium oxide, tantalum oxide, silicon oxide, etc. The reflective layer is selected from reflective metals such as aluminum, silver, copper, and gold. The first and second absorption layers and the first and second dielectric layers are preferably made of the same material. In the five-layer structure, the dielectric layer and the absorption layer can be omitted from one side of the reflective layer to form a three-layer structure.

  The optical interference reflection structure in the above invention has a laminated structure of a light absorption layer composed of a metal layer, an inorganic oxide layer related to the interference action, and a metal layer that increases the reflection intensity of light in the layer. Therefore, there is a drawback that it is difficult to achieve the color development design. In addition, since a metal is used for the reflective layer, the heat-resistant atmosphere is generally dependent on a lower melting point than those oxides. In addition, it becomes opaque depending on the situation of the layer thickness control, and there is a high possibility that the transmission of light to the inside of the structure is hindered and a target light interference function is hindered. When the three-layer structure is adopted, the amount of reflected light on the surface layer of the reflective layer is large, and there is a high possibility that a sufficient light interference function cannot be obtained.

  There is also an optical interference reflection structure applying the above example, which is characterized by using a titanium-based material for the absorption layer. (Patent Document 2)

  The optical interference reflection structure according to the above two examples is configured to show two reflection peaks in the visible light region by selecting materials used for the absorption layer and the dielectric layer as shown in the examples. In any case, the function of the absorption layer is to be an object color accompanying light absorption inherent to the metal used in the absorption layer, which is different from interference color development, and a sharp reflection peak cannot be obtained with the two-layer structure of the absorption layer and the dielectric layer. Therefore, it is very difficult to obtain a single deep color.

  Another example provides a color forming structure having a reflection interference effect that can be easily manufactured and can reliably and stably obtain a vivid color tone at a desired wavelength. This example uses two types of organic polymer polymers as materials, has a layered structure consisting of two layers of alternating multilayers, and develops a color in the wavelength range of visible light by the reflection interference action of natural light. (Patent Document 3)

  As an example of shielding infrared rays or ultraviolet rays, there is a structure that reflects one or both of near ultraviolet rays and near infrared rays. As in the above example, an organic polymer is used as a material, and two substances are alternately laminated in layers. (Patent Document 4)

  In these two types of structures, since the material used is an organic polymer, the refractive index ratio cannot necessarily be increased. Therefore, in order to exhibit clear color development, it is necessary to take a very multi-layered structure. In addition, organic polymer polymers generally have a low glass transition point, and the design layer thickness of each layer cannot be maintained in a high-temperature atmosphere, for example, 200 ° C. or higher. Therefore, the light reflection interference function including predetermined color development is maintained. There is a drawback that you can not.

In addition, as an optical interference reflection structure that is expected to have heat resistance, there is a method in which a thin metal layer is formed on the surface of mica pieces or silica particles by vapor deposition or plating, and an oxide layer is formed by post-processing to cause interference color development. is there. The problem here is that the smoothness of the substrate surface is low, and it is difficult to interfere and reflect only the predetermined light wavelength, resulting in various colored hues. Since the edge effect of the structure cannot be obtained, for example, when applied to a coating pigment, it is difficult to obtain a glitter feeling.
US Pat. No. 6,157,489 US Pat. No. 6,569,529 Japanese Patent Laid-Open No. 7-034324 JP-A-7-195603

  The problem to be solved by the present invention is to provide an optical interference reflection structure having unprecedented heat resistance and a pigment thereof, on which a release layer made of a highly brittle material is provided on the heat resistant substrate or on the substrate. In addition, by devising a laminated structure composed of at least two kinds of inorganic materials, obtaining a high reflection function of a design specific wavelength, further removing the peeling layer, and separating and collecting the alternately laminated portion and the substrate portion, The object is to obtain a heat-resistant optical interference reflection structure having an interference reflection function.

  In order to solve the above problems, two materials selected from compounds capable of forming inorganic oxides or inorganic sulfides having different optical refractive indices are transparent and reflect a predetermined light wavelength. A continuous alternating laminated structure is obtained within the optical thickness range. It is characterized by interfering and reflecting at least one wavelength from the visible light region, the ultraviolet region, or the infrared region. Further, the boundary surfaces of the layers of the structure body are laminated in parallel with a predetermined thickness while avoiding mutual migration as much as possible. In this structure form, by selecting the refractive index ratio due to the above-described inorganic oxide or inorganic sulfide as large as possible, the reflection spectrum of the designed predetermined light can be sharpened with a reduction in the number of layers, In particular, in the visible light region, a heat-resistant coloring material that induces a sense of depth can be obtained. Further, the optical interference reflection structure is changed to a plate-like, film-like, and micro-piece-like optical interference reflection structure to expand the application range.

を等しくした時、設計最大反射率を得ることができる。In the optical interference reflection structure, the refractive index of the first material n _a, the thickness d _a, the refractive index n _b of the second _material, when the layer thickness and d _b, ultraviolet light region, Visible light region and infrared light region

Is equal, the design maximum reflectivity can be obtained.

The possible range of the thickness d _a of the first material and the thickness d _b of the second material can be designed so as to obtain a predetermined reflection wavelength within a range satisfying the above relational expression. If the molding error of the design thickness of both material layers becomes large, the design reflection strength will be adversely affected, so it is necessary to pay close attention to the layer thickness accuracy, but only two different inorganic oxides or sulfides are used. It is possible to reflect various desired wavelengths simply by changing the thickness.

  The two materials having different optical refractive indices are preferably as highly transparent as possible for realizing the optical interference reflection structure in the present invention. For example, zirconium oxide, tantalum oxide, silicon monoxide, silicon dioxide, aluminum oxide Cerium oxide, hafnium oxide, titanium oxide, praseodymium oxide, yttrium oxide, zinc oxide, zinc sulfide, or a mixture of various inorganic oxides and inorganic sulfides. Among these, depending on the purpose and application, 2 Select the type of material and form the alternating stack. These are merely examples, and the constituent materials of the present invention are not limited by these.

When natural light is incident on the layer in the longitudinal direction, there are two ways of alternately stacking the first material (optical refractive index n _a ) and the second material (optical refractive index n _b ). That is, the first material layer / the second material layer / the first material layer / the second material layer are laminated from the surface layer on which natural light is incident, and the second material layer / the first material layer / In this case, the second material layer / first material layer are stacked. In order to increase the reflection on the surface, that is, to increase the glossiness, it is desirable to use an alternating layered structure in which a surface layer is made of a material having a high refractive index. The number N of stacked structures in the present invention refers to one pair of first material layer / second material layer.

  The number of stacked pairs N of the structure and the refractive index ratio of the constituent materials are very important factors related to the reflectance. For example, in the visible light region, when the refractive index ratio is about 1.5, the N is about 7, and an energy reflectance of about 0.8 or more at the maximum reflection wavelength is obtained, and a very clear color development is easily obtained. In the case where the refractive index ratio is 1.1 or less, if an energy reflectance similar to that described above is to be obtained, there is a high possibility that N is 30 or more, that is, 60 or more layers are required. Therefore, the choice of material is very important. As the refractive index ratio increases or as N increases, the energy reflectance increases and the maximum reflection spectrum becomes sharper, as shown in the graph of FIG.

  In the formation of a plate-like, film-like or micro-piece-like optical interference reflection structure, first, the multilayer structure layer and the substrate are provided in close contact with each other, and secondly, the release layer is sandwiched between the multi-layer and the substrate. In some cases, only the multilayer laminated portion is removed after use.

  When the first method is used, a substrate in which two kinds of inorganic materials are laminated is used as it is as a plate-like or film-like material, or when it is made into a minute piece, it is laminated on the substrate. Crush. In this case, a transparent heat-resistant film or glass is selected as the substrate. In addition, when the aspect ratio regarding the plane parallel to the layer plane and the plane perpendicular to the layer plane is small, the probability that the minute piece is directed in a certain direction is reduced, and the light reflection interference function is suppressed. Considering this, it is better that the aspect ratio is large. It is good to adjust according to the application.

  In the second case, there are several peeling methods. As one of them, a VIa or IVb group metal of the periodic table having a relatively high brittleness, such as tungsten, is used as a peeling layer between the substrate and the multi-layer. It is used as a glass substrate or heat-resistant film as a substrate, properly deposited by sputtering, etc., and after providing a predetermined light interference reflection laminate on it, it is removed by immersing in liquid nitrogen etc. and rapidly peeling off is there. Thereafter, it is separated and separated by a sieve or the like to obtain only the alternately laminated portion.

  Further, as another method in the second case, there is a method of using an alternate laminated layer or a substance having a lower melting point than the substrate or a substance soluble in an organic solvent as a release layer between the substrate and the multi-layer, and removing by using a solvent is there. In this case, materials suitable for the release layer include materials such as acrylic resin, cellulose propionate, polyvinyl alcohol or acetate.

  After peeling by the method as described above, the laminated portion is used as a plate-like or film-like material, or is used after being miniaturized to a desired size.

  It is possible to reflect various desired wavelengths only by changing the thickness of the material using two different inorganic oxides or inorganic sulfides. This makes it possible to provide a single deep color in the visible light region and to control its influence in the infrared region and the ultraviolet region. In addition, since this structure has high heat resistance and durability and can be used not only in a normal temperature atmosphere but also in a high temperature atmosphere, it may be used in a wide range of applications.

  1 and 2 are explanatory views schematically showing a heat-resistant optical interference reflection structure according to an embodiment of the present invention. FIG. 1 shows that a metal constituting a low refractive index inorganic oxide or inorganic sulfide is deposited on a heat-resistant transparent thin glass substrate by a technique such as sputtering so as to have a predetermined optical thickness, and then in an oxidizing atmosphere. Alternatively, a low refractive index layer is formed by heating in an atmosphere that becomes a target compound, such as in a sulfurized atmosphere, and then a higher refractive index inorganic oxide or inorganic type so as to have a predetermined optical thickness thereon. A substance that becomes sulfide is deposited and heated in an atmosphere that becomes the target compound, such as in an oxidizing atmosphere or a sulfurizing atmosphere, to form a high refractive index layer, and these treatments obtain reflectance at a predetermined wavelength. It is a schematic cross-sectional form of the reflective structure obtained by repeating as described. Another vapor deposition method may be chemical vapor deposition, combustion chemical vapor deposition, or the like. In this case as well, the low refractive index layer and the high refractive index layer are alternately laminated on the substrate in an atmosphere that becomes the target compound, such as in an oxidizing atmosphere or a sulfurizing atmosphere, as described above. There is no. In addition, the schematic cross-sectional form shown in FIG. 2 is provided by providing a release layer of a highly brittle substance or an easily removable substance in order to form a predetermined inorganic oxide or inorganic sulfide on the substrate. This is a configuration for obtaining only the functional film portion by post-processing after forming the functional thin film multilayer layer. The substance and peeling method used as the peeling layer are as described above.

Example 1
The reflective structure shown in FIG. 1 was formed according to the following. The design reflection wavelength was 470 nm. Silicon dioxide was selected for the low refractive index layer, and titanium dioxide was selected for the high refractive index layer. The refractive indexes are 1.5 and 2.4, respectively, and the refractive index ratio is 1.6. The thickness of the layer was set to 78 nm for silicon dioxide and 49 nm for titanium dioxide according to the above equation 2. First, silicon dioxide is vapor-deposited by sputtering on a heat-resistant transparent glass substrate and then fired, and then titanium dioxide is vapor-deposited and fired by sputtering. Seven pairs (14 layers) were alternately molded repeatedly, and evaluated using a spectrophotometer (model U-6000: Hitachi, Ltd.) at 0 ° incidence / 0 ° light reception. The results are shown in Table 1 below.

(Example 2)
The reflective structure shown in FIG. 1 was formed according to the following using a combination of inorganic materials different from Example 1. The design reflection wavelength was 470 nm. Aluminum oxide was selected for the low refractive index layer and zinc sulfide was selected for the high refractive index layer. The refractive indexes are 1.6 and 2.4, respectively, and the refractive index ratio is 1.5. The thickness of the layer was set to 73 nm for aluminum oxide and 49 nm for zinc sulfide according to Equation 2 described above. First, aluminum oxide is vapor-deposited on a heat-resistant transparent thin glass substrate, and further vapor-deposited using zinc sulfide. Seven pairs (14 layers) were alternately molded repeatedly, and evaluated using a spectrophotometer (model U-6000: Hitachi, Ltd.) at 0 ° incidence / 0 ° light reception. The results are shown in Table 1 below.

(Example 3)
The reflective structure shown in FIG. 1 was formed according to the following using a combination of inorganic materials different from Example 1. The design reflection wavelength was 470 nm. Aluminum oxide was selected for the low refractive index layer and titanium dioxide was selected for the high refractive index layer. The refractive indexes are 1.6 and 2.4, respectively, and the refractive index ratio is 1.5. The thickness of the layer was set to 73 nm for aluminum oxide and 49 nm for titanium dioxide according to the above formula 2. First, aluminum oxide is vapor-deposited on a heat-resistant transparent thin glass substrate, and further vapor-deposited using titanium dioxide. Seven pairs (14 layers) were alternately molded repeatedly, and evaluated using a spectrophotometer (model U-6000: Hitachi, Ltd.) at 0 ° incidence / 0 ° light reception. The results are shown in Table 1 below.

上述した例はあくまで例示であって、制約されるものではない。本発明の範囲は上記の例によるものよりもむしろ記載する特許請求の範囲によって示される。

The above-described examples are merely examples and are not limited. The scope of the invention is indicated by the appended claims rather than by the above examples.

Example 4
An optical interference reflection structure having a design reflection wavelength of 900 nm was formed. Three types of reflective structures having a refractive index ratio of 1.1, 1.3, and 1.5 were formed on a float plate glass substrate having a thickness of 3 mm in the same manner as in Example 1. The results of measuring each maximum reflectance are shown in Table 2 below. Using a spectrophotometer (manufactured by Hitachi, a self-recording spectrophotometer), the evaluation was carried out at 0 ° incidence / 0 ° light reception.

(Example 5)
An optical interference reflection structure having a design reflection wavelength of 350 nm was formed. Three types of reflective structures having a refractive index ratio of 1.1, 1.3, and 1.5 are formed on a 3 mm-thick float glass substrate in the same manner as in Example 1, and the maximum reflectance is measured. The results are shown in Table 3 below. Using a spectrophotometer (model U-6000: Hitachi, Ltd.), evaluation was performed at 0 ° incidence / 0 ° light reception.

(Example 6)
In the configuration of Example 1, an optical interference reflection structure in which a peeling layer was sandwiched between the substrate and the laminated layer was formed. The design reflection wavelength was 470 nm. Tungsten is vapor-deposited on a float plate glass substrate having a thickness of 3 mm, and seven pairs of silicon dioxide layers and titanium dioxide layers are alternately formed in the same manner as in the first embodiment. This was immersed in liquid nitrogen and crushed, then separated in two stages using a sieve, and only the alternately laminated portions were collected. When the reflection spectrum of the obtained optical interference reflection structure pigment was measured, the maximum reflectance was 83%.

(Example 7)
In the configuration of Example 1, an optical interference reflection structure in which an acrylic resin was sandwiched between the substrate and the laminated layer as a release layer was formed. The design reflection wavelength was 470 nm. Acrylic resin is vapor-deposited on a 3 mm thick float glass substrate, and seven pairs of silicon dioxide layers and titanium dioxide layers are alternately formed in the same manner as in Example 1. This was immersed in an organic solvent to dissolve the acrylic resin, and only the alternately laminated portions were collected. When the reflection spectrum of the obtained optical interference reflection structure pigment was measured, the maximum reflectance was 82%.

  From our experience so far, it has been found that paint pigments tend to give a sense of depth when the coating becomes sharper as the reflection spectrum becomes sharper. By using the fine piece obtained by the present invention as a pigment, it is possible to provide a paint that gives a sense of depth, and it can be used for automobiles, electrical equipment, building materials, toys, cosmetics, and the like where the appearance impression is important. Since this reflective structure has high heat resistance, the degree of freedom of use is high. FIG. 4 shows the relationship between the temperature change and the refractive index of the interference reflector made of an organic polymer and the reflection interferer according to the present invention. These differences are contrasted in heat resistance. For example, in the case of an interference reflection structure made of polyethylene terephthalate and nylon, the reflection interference body made of an organic polymer cannot maintain the initial function by changing the layer thickness immediately after being exposed to an atmosphere of about 200 ° C. However, there is no problem at all in the reflection interference structure according to the present invention. When this is used as an automobile pigment, a pigment formed from an organic substance is difficult to apply due to the baking temperature of the paint, but an inorganic pigment made of this reflective structure can withstand high temperatures.

  If a film reflecting the infrared light region is attached to the glass surface of the building, it functions as a heat-resistant film. Moreover, when the coating material containing the micro piece which reflects an infrared-light area | region is applied to building materials, such as a tile, it can contribute to energy reduction, for example, can raise heating efficiency. If a film that reflects the ultraviolet light region is pasted on the glass surface of the building, or a coating containing fine pieces reflecting the ultraviolet light region is coated on the glass surface of the building, the transparency and UV resistance are high. It becomes an effective film. Since it is composed of an inorganic material, the deterioration due to ultraviolet irradiation is extremely small, and it can be applied in a wide range including building materials.

  The plate-like, film-like, and minute piece-like optical interference reflection structures described above have high heat resistance and durability, and thus have excellent workability and may be used for various applications.

It is a figure which shows the structure which laminated | stacked 3 pairs of two types of inorganic type materials from which an optical refractive index differs continuously on a transparent substrate. It is a figure which shows the structure which pinched | stacked the peeling layer between lamination | stacking of two types of inorganic type materials from which an optical refractive index differs, and a board | substrate. (A), (b), (c) is a graph which shows the relationship between a refractive index ratio and the energy reflectance by the number of lamination | stacking pairs. It is a graph which shows the relationship between a temperature change and a maximum reflectance.

Explanation of symbols

101 Substrate 102 Low-refractive index inorganic oxide layer or inorganic sulfide layer 103 High-refractive index inorganic oxide layer or inorganic sulfide layer 104 Release layer

Claims (7)

The substrate has a laminated structure in which two components selected from inorganic oxides or inorganic sulfides having different optical refractive indexes are alternately continuous within an optical thickness range in which each component is transparent, or A structure in which a release layer made of a highly brittle material layer is provided between the substrate and the laminated structure, and the laminated structure portion sharpens at least one wavelength in an ultraviolet region, a visible light region, and an infrared region. A heat-resistant optical interference reflection structure characterized by interference reflection. The release layer on a substrate such as glass or heat-resistant film is a metal species selected from Group VIa and Group IVb of the periodic table, preferably a metal selected from molybdenum, tungsten, and tin A heat-resistant optical interference reflection structure characterized in that A heat-resistant optical interference reflection structure obtained by separating and collecting the alternately laminated pieces after quick freezing and crushing the structure according to claim 1 or 2. The heat-resistant optical interference reflection structure according to claim 1, wherein the release layer is selected from an acrylic resin, cellulose propionate, polyvinyl alcohol, and acetates having dissolution peelability. 5. The structure of the alternately laminated structure according to claim 1, 2, 3, 4, wherein zirconium oxide, tantalum oxide, silicon monoxide, silicon dioxide, aluminum oxide, cerium oxide, hafnium oxide, titanium oxide, praseodymium oxide, yttrium oxide A heat-resistant optical interference reflection structure characterized in that the structure is composed of an oxide system such as zinc oxide or zinc sulfide, a sulfide system, or a composite thereof, preferably composed of the same system. 6. The heat-resistant optical interference reflection structure, wherein the number of stacked layers of the structure according to claim 1, 2, 3, 4, and 5 is two or more. 7. The heat resistant optical interference reflection structure according to claim 1, wherein the heat resistance of the alternately laminated structure according to claim 1 can be used at 300 [deg.] C. or higher.

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