JP2005181642A - Photochromic device and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the handling of a photochromic material whose optical transmission property varies upon UV irradiation. <P>SOLUTION: The photochromic material containing composite oxide of tin oxide and magnesium oxide and an electrically conductive film is formed on a metal substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a recording medium whose optical characteristics change when irradiated with light energy and a method for manufacturing the same, and more particularly to a photochromic element using a photochromic material and a method for manufacturing the same.

  It has become possible to easily obtain the desired information using the Internet. This information is usually displayed on a display device, but is generally used in the form of a printed material as a hard copy. However, from the viewpoint of effective use of resources, it is desired to use a hard copy that can be used repeatedly from conventional printing on paper.

As a reusable recording material, it is possible to use a material whose optical transmission characteristics change by irradiating light. One of them is an organic material such as a chromene-based photochromic material (for example, Patent Document 1). reference.). Such a material whose optical transmittance is changed by light irradiation is promising as a hard copy material that can be used repeatedly. However, in the case of organic materials such as the above-mentioned chromene-based photochromic materials, a few seconds are obtained by irradiating light. When it is made opaque and left in a dark place, it returns to a transparent state in a few seconds to a few minutes. However, after making it opaque by irradiating light, there is a problem that stable optical transmission characteristics cannot be obtained.
JP, 6-192651, A (pages 2-7) In view of the above problems, the present inventors have proposed that a laminated film in which a transparent conductive material and a composite oxide of an inorganic material are laminated is optically transmitted by ultraviolet irradiation. It came to invent the photochromic body from which a characteristic changes (Japanese Patent Application 2002-159484). In the present invention, the photochromic body is mainly formed on the glass substrate.

  The problems of the conventional photochromic material have been solved by the above-mentioned inventions of the present inventors. Furthermore, in order to bring the photochromic material as a recording material closer to the convenience of a printed matter of a conventional paper, the present invention is the above-mentioned invention. A photochromic device using the photochromic material of Japanese Patent Application No. 2002-159484, a photochromic element that has a structure that makes the difference in brightness between a portion irradiated with ultraviolet rays and a non-irradiated portion of the photochromic material, and is easier to handle, and a method for manufacturing the same. Is an issue.

  In order to solve the above problems, in the first aspect of the present invention, a photochromic body including a photochromic material and a conductive film is used as a metal substrate, a glass substrate, a ceramic substrate, a metal substrate with a roughened surface, or a metal Provided on a substrate provided with a ceramic layer on the substrate, increase the reflectivity of the substrate surface, facilitate light scattering on the substrate surface, or whiten the substrate surface and irradiate the photochromic body with ultraviolet rays for recording This makes it easier to visually recognize the characters, figures, and the like.

  Furthermore, in the second aspect of the present invention, a reinforcing layer is provided on a substrate on which a photochromic body including a photochromic material and a conductive film is attached, thereby facilitating the handling of the photochromic element.

  Furthermore, in the third aspect of the present invention, a photochromic body including a photochromic material and a conductive film is formed on the first substrate, the photochromic body is transferred to the second substrate, and the second substrate is transferred. The photochromic body is formed on the surface. For example, a photochromic body having a photochromic material and a conductive film can be formed on a material having thermoplasticity or a substrate having an uneven surface, and the photochromic body is easy to handle. It can be formed on a substrate.

  The photochromic element of the present invention increases the reflectivity of the substrate surface on which the photochromic body is applied, or is roughened or whitened, so that the visibility of the portion where the optical transmission characteristics of the photochromic body are changed is improved. Since the substrate on which the photochromic body is formed can be reinforced and the photochromic body can be transferred and formed on various substrates, the photochromic element can be easily handled.

  It is possible to improve the visibility of the places where the optical transmission characteristics of the photochromic body including the photochromic material and the conductive film have changed, to reinforce the substrate that forms the photochromic body, and to transfer the photochromic body to various substrates Realized a photochromic device that is easy to handle, similar to printed materials using paper.

  FIG. 1 shows the principle of operation in which the optical transmission characteristics of the photochromic body according to the present invention change due to ultraviolet irradiation in the case of joining a tin oxide-doped indium oxide (hereinafter referred to as ITO) film and a composite oxide film of tin and magnesium. Show. The principle of operation is not completely elucidated, but is considered as follows.

  It is thought that the band diagram of the junction between ITO and the composite oxide of tin and magnesium is as shown in FIG. From the left side of the figure, the order is ITO, intermediate crystal, and tin / magnesium composite oxide. The band gap between the conduction band 11 and the valence band 13 of ITO is 3.75 eV (measured value), and the band gap of the composite oxide of tin and magnesium is 4.25 eV. The Fermi level 12 of ITO is near the conduction band 11, and the Fermi level of the composite oxide of tin and magnesium is considered to be between the conduction band 11 and the valence band 13.

  In the state during the ultraviolet irradiation shown in FIG. 1B, the electrons 15 in the valence band 13 of the intermediate crystal portion are excited by the conduction band 11 by the irradiation of the ultraviolet rays 16, and the excited electrons 15 are excited in the conduction band 11. Is accommodated in the conduction band of ITO. On the other hand, holes 14 from which electrons have been removed remain in the valence band 13.

  After irradiation with ultraviolet rays in FIG. 1 (c), the holes 14 in the intermediate crystal portion have time until recombination, so that the atomic arrangement changes during this period, and the order in which the holes 14 are present is between the band gaps. To form a new level 17 and appear as a coloring order.

  Because of the above mechanism, a coloring reaction occurs on the composite oxide side of the interface between the composite oxide and ITO. Therefore, the more the interface between the composite oxide and ITO, the greater the photochromic effect of the present invention.

  Here, the description has been made by taking a photochromic body made of a composite oxide of tin and magnesium and ITO as an example. However, the composite oxide is a group of Ti, Mn, Co, Ni, Zn, Sn on the same operation principle. The same effect can be obtained by using a composite oxide of at least two elements selected from the group consisting of Mg, Al, and Si and ITO. Further, the transparent conductor is not limited to ITO, and any material such as tin oxide and zinc oxide may be used as long as it is a transparent conductive material exhibiting the characteristics of an n-type semiconductor.

FIG. 2 is a view for explaining the above-described method for producing a photochromic body of the present invention, and shows a process diagram for forming a composite oxide film of tin and magnesium by a coating pyrolysis method.

  First, as shown in step (a) of FIG. 2, an ITO film 2 having a thickness of 0.2 μm is formed on a glass substrate 1 made of a support by sputtering.

  Next, as shown in step (b) of FIG. 2, 10 g of each of caproic acid tin and magnesium caproate are dissolved in 10 g of ethyl alcohol, and this liquid is applied as a coating liquid 3 on the ITO film with a spinner 4 at a rotational speed of 1200 rpm. Apply to. After application, the film is dried for 10 minutes in a drying oven at 60 ° C.

  After drying the coating solution applied on the ITO film 2, the glass substrate 1 is baked at 400 ° C. for 1 hour in a baking furnace, so that the film thickness is 0.4 μm as shown in step (c) of FIG. A composite oxide film 5 of tin and magnesium is formed on the ITO film 2. The amount of defects of oxygen atoms in the composite oxide has a larger amount of defects when the firing temperature is lower, and the amount of defects decreases when the firing temperature is higher. Further, the lower the oxygen concentration in the firing atmosphere, the larger the amount of defects, and the higher the oxygen concentration, the smaller the amount of defects. That is, the amount of oxygen atom defects in the composite oxide can be adjusted by the firing temperature and the oxygen concentration in the firing atmosphere. The amount of oxygen atom defects is preferably in the range of 1% to 70%. Outside this range, the optical transmission characteristics due to ultraviolet irradiation do not change.

  By irradiating a mercury lamp having a wavelength of 185 nm with a light amount of 30 mW / cm 2 to the photochromic body made of the laminated film of the ITO film 2 and the composite oxide film 5 of tin / magnesium for 5 minutes, visible light is obtained. The transmittance could be changed from 95% to 30%. Further, after changing the transmittance by irradiating with ultraviolet rays, the sample was left standing under room light for 12 months, but the visible light transmittance did not change.

  In addition, although the caproic acid tin and the caproic acid magnesium were illustrated as a raw material, especially fatty acid tin and a fatty acid magnesium may be used, When using raw materials other than a caproic acid magnesium and a caproic acid magnesium, the weight of the raw material dissolved Will change. Further, by changing the weight ratio of these raw materials dissolved in ethyl alcohol, the atomic ratio contained in the composite oxide film can be adjusted. The atomic ratio of tin and magnesium is preferably between 3: 7 and 7: 3. Outside this range, the optical transmission characteristics are not changed by ultraviolet irradiation.

Although the coating pyrolysis method has been described above as a method for forming the composite oxide film, a sol-gel method, a CVD method, a vapor deposition method, an ion plating method, or a sputtering method may be used. In that case, in the CVD method, (CH ₃ ) ₂ SnCl ₂ and Mg (C ₅ H ₇ O ₂ ) ₂ are vaporized as raw material gases, oxygen and nitrogen are mixed to generate plasma, and heated to 500 ° C. Deposit on a glass substrate. In the case of employing a vapor deposition method, tin oxide and magnesium oxide may be used as a vapor deposition source, or metal tin and metal magnesium may be vapor-deposited in an oxygen atmosphere. In the case of employing the sputtering method, tin oxide and magnesium oxide are used as a sputtering target, and film formation is performed by adjusting the sputtering atmosphere and the substrate temperature.

  The transparent conductive material is not limited to ITO, and materials such as tin oxide and zinc oxide may be used. The film forming method is not limited to the sputtering method, and a method such as a vapor deposition method, an ion plating method, a CVD method, or the like. You may form into a film using.

  In the above description, the case where the glass substrate 1 is used as the support has been described as an example, but instead of the glass substrate 1, a thin metal, for example, SUS304 having a thickness of 0.1 mm may be used as the substrate. Since this thin metal is used as a substrate, it is possible to obtain a photochromic element that is flexible and has good reflection of light transmitted through the photochromic body, is easy to handle, and has improved visibility between ultraviolet irradiated and non-irradiated areas. .

  Further, the above-mentioned photochromic element may be formed by forming fine irregularities by sandblasting on the surface of the substrate surface using a thin metal such as SUS on which the photochromic body is provided. In this case, since the light transmitted through the photochromic body is scattered by minute unevenness, the distinction between the ultraviolet irradiation site and the non-irradiation site can be visually recognized with a wide field of view. The minute irregularities can be formed by using an etching solution other than by sandblasting.

  Furthermore, ceramic particles were deposited on the substrate such as SUS by thermal spraying to form a ceramic layer having a thickness of about 40 μm, and the photochromic body was formed on the ceramic layer.

  The ceramic particles preferably have a white color, such as alumina, and by providing this ceramic layer, the whiteness of the ultraviolet non-irradiated portion is improved and the visibility to the non-irradiated portion is improved.

  In addition, you may form a ceramic layer using the ceramic application | coating method besides the said thermal spraying.

In Example 2 shown in FIG. 3, a photochromic body having a laminated film structure in which an ITO film is sandwiched between two composite oxide films is formed. First, as shown in step (1) of FIG. 3, tin oxide and magnesium oxide are formed on the glass substrate 1 as a support by the method described in steps (b) and (c) of FIG. A first composite oxide film 5a having a thickness of 0.4 μm is formed. Next, as shown in step (2) of FIG. 3, an ITO film 2 is formed to a thickness of 0.2 μm on the composite oxide film 5a by sputtering. Next, as shown in step (3) of FIG. 3, a second composite oxide film 5b of tin oxide and magnesium oxide having a thickness of 0.4 μm is formed on the ITO film 2 with the first composite oxide film 5a. It is formed by the same manufacturing method. Thus, a photochromic body composed of a laminated film in which the ITO film 2 is sandwiched between the two composite oxide films 5a and 5b is obtained.

  As a modification of this, as shown in FIG. 4, an ITO film 2a having a thickness of 0.2 μm is first formed on a glass substrate 1, and a composite oxide having a thickness of 0.4 μm is formed on the ITO film 2a. Contrary to the structure shown in FIG. 3 in which the film 5 is formed and the ITO film 2b having a thickness of 0.2 μm is formed thereon, a photochromic body having a laminated film structure in which a composite oxide film is sandwiched between ITO films is conceivable. .

  The laminated film structure in which the composite oxide film and the ITO film of Example 2 shown in FIGS. 3 and 4 are sandwiched is more suitable than the laminated film structure of the composite oxide film and the ITO film. This is a more preferable structure.

FIG. 5 is a diagram showing the transmittance of the photochromic body obtained in Example 2, and is data of the transmittance of the photochromic body before and after irradiating 185 nm ultraviolet rays with a light amount of 30 mW / cm ² for 5 minutes. In this figure, the vertical axis represents the transmittance (%) with air as 100%, and the horizontal axis represents the light wavelength (nm). The measurement was performed using UV-3100S manufactured by Shimadzu Corporation. The thick line indicates the transmittance before ultraviolet irradiation, and the thin line indicates the transmittance after ultraviolet irradiation. The transmittance at a wavelength of 550 nm was changed to 86% before irradiation with ultraviolet light and 4.7% after irradiation. After the change, the material was left under room light for 6 months, but no change was observed in the transmittance.

  In the second embodiment, similarly to the first embodiment, instead of the glass substrate 1, a thin metal film, for example, SUS304 having a thickness of 0.1 mm may be used as the substrate, and this thin metal is used as the substrate. Therefore, it is possible to obtain a photochromic element that is flexible and has good reflection of light transmitted through the photochromic body, is easy to handle, and has improved visibility between the ultraviolet irradiation site and the non-irradiation site.

  Moreover, the above-mentioned photochromic element may be formed by forming minute irregularities by sandblasting on the surface of the substrate surface using the thin metal on the side where the photochromic body is provided. In this case, since the light transmitted through the photochromic body is scattered by minute unevenness, the distinction between the ultraviolet irradiation site and the non-irradiation site can be visually recognized with a wide field of view. The minute irregularities can be formed by using an etching solution other than by sandblasting.

  Furthermore, ceramic particles were deposited on the SUS substrate by thermal spraying to form a ceramic layer having a thickness of about 40 μm, and the photochromic body was formed on the ceramic layer.

  The ceramic particles preferably have a white color, such as alumina, and by providing this ceramic layer, the whiteness of the ultraviolet non-irradiated portion is improved and the visibility to the non-irradiated portion is improved.

  In addition, you may form a ceramic layer using the ceramic application | coating method besides the said thermal spraying.

  Further, a configuration in which a resin layer having a known ultraviolet absorber is provided on the side opposite to the substrate 110 of the photochromic body 120 is also effective. Characters and the like are written in advance on the photochromic element with ultraviolet rays, but by providing this resin layer, it is possible to prevent a portion that has not been irradiated with ultraviolet rays from being changed to yellow or the like by ultraviolet rays from a fluorescent lamp or the like, A photochromic element with good visibility over a long time can be obtained. Also, by providing this resin layer, the photochromic body can be prevented from absorbing moisture and damaged, and a photochromic element with better handling can be obtained. In order to prevent moisture absorption and damage of the photochromic body, it is not necessary to include an ultraviolet absorber in the resin layer.

Example 3 shown in FIG. 6 is a photochromic element 100 in which the substrate side of the photochromic element prepared in Example 1 or Example 2 is reinforced, and FIG. 6 is a cross-sectional view of the photochromic element 100. In Example 3, 0.05 mm thick borosilicate glass is used for the substrate 110, and the photochromic body 120 is formed on the substrate 110 by the method described in Example 1 or Example 2, and this A reinforcing layer 130 is provided via an adhesive on the substrate surface opposite to the side on which the photochromic body 120 is formed. The end portion of the photochromic body 120 and the peripheral portion of the reinforcing layer 130 are bonded by the end portion adhesive layer 140. The reinforcing layer 130 is preferably white paper, but may be coated with leather or the same adhesive as the end adhesive layer 140. In addition, although vinyl acetate etc. can be used as an adhesive agent, it is preferable to use the adhesive agent which mixed white pigments, such as an alumina.

  When paper, leather, or the like is used as the above-described reinforcing layer, it is also a preferred embodiment to print marks, characters, figures, etc. on these paper or leather in advance.

  In Example 4 shown in FIG. 7, after the photochromic body 210 is formed on the first substrate 200 by the method described in Example 1 and Example 2 in Step (1), the adhesive layer 221 is formed in Step (2). After pressing and adhering the second substrate 220 to the photochromic body 210, the photochromic body 210 is peeled from the first substrate 200, and the photochromic body 210 is transferred onto the second substrate 220 shown in step (3). This is a method for manufacturing the photochromic element 250.

  In Example 4, a white resin sheet (for example, polyethylene terephthalate (PET)) having a white pigment or the like is used for the second substrate 220, and an epoxy resin adhesive layer 221 is provided on the white sheet. The layer 221 attaches the photochromic body 210 to the substrate 220.

  According to the manufacturing method of the fourth embodiment, the photochromic body 210 can be formed on a hard substrate such as a glass substrate or a metal substrate, the thickness can be accurately manufactured, and then the photochromic body is formed on the second substrate 220. Since 210 is transferred to the second substrate 220, the photochromic body 210 can be formed as a second substrate 220 on a member made of a flexible material such as resin, paper, leather, and the photochromic element 250 suitable for handling. Is obtained.

  Furthermore, it is possible to transfer the photochromic body to a cylindrical, polygonal, or uneven surface.

  In addition, if a large number of spherical concave surfaces are provided on the first substrate 200 to form the photochromic body 210, the photochromic element 210 having the convex spherical surface can be formed in the photochromic element 250, and the photochromic element 250 is formed using ultraviolet rays. When writing, etc., the irradiated ultraviolet rays are narrowed down in the photochromic body 210, so that even if the boundary between the second substrate 220 and the photochromic body 210 is roughened, the degree of ultraviolet light scattering is weakened. Therefore, it is possible to write characters or the like with less blur.

  Example 5 shown in FIG. 8 is a diagram showing a cross section of a photochromic element 300 in which the photochromic body 210 is formed on both surfaces of the second substrate 220 using the method of manufacturing a photochromic element by transfer described in Example 4. . The photochromic bodies 210 formed on both sides of the second substrate 220 are all formed on a hard substrate such as a glass substrate or a metal substrate, and then transferred to the second substrate 220. Similarly to the photochromic body 4, the photochromic body 210 having a precise thickness can be formed on both surfaces of the flexible second substrate 220.

  The photochromic element of the present invention increases the reflectance of the substrate surface on which the photochromic body is deposited, or is roughened or whitened, so that the visibility of the portion where the optical transmission characteristics of the photochromic body have changed is improved. The substrate that forms the photochromic body can be reinforced, and the photochromic body can be transferred and formed on various substrates, making it easy to handle the photochromic element, and can be used as a hard copy in the same way as conventional printed materials. Yes, it can be used repeatedly.

FIG. 4 is an operation principle diagram in which the optical transmission characteristics of the photochromic body according to the present invention by ultraviolet irradiation change. The figure which shows the manufacturing method of the photochromic body which concerns on Example 1 of this invention. The figure which shows the manufacturing method of the photochromic body which concerns on Example 2 of this invention. The figure which shows the modification of the photochromic body which concerns on Example 2 of this invention. The figure which shows the transmittance | permeability characteristic of the photochromic body of this invention before and behind ultraviolet irradiation. The figure which shows the section of a photochromic element The figure which shows the manufacturing method of a photochromic element. The figure which shows an example of a photochromic element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 ITO film 2a ITO film 2b ITO film 3 Coating liquid 4 Spinner 5 Composite oxide film 5a Composite oxide film 5b Composite oxide film 11 Conductive band 12 Fermi level 13 Valence band 14 Hole 15 Electron 16 Ultraviolet 17 New level 100 Photochromic element 110 Substrate 120 Photochromic body 130 Reinforcing layer 200 First substrate 210 Photochromic body 220 Second substrate 300 Photochromic element

Claims (5)

A metal substrate;
A photoconductive film including a transparent conductive film and a composite oxide film formed on the transparent conductive film and made of a composite oxide of tin oxide and magnesium oxide and having optical transmission characteristics changed by ultraviolet irradiation.
A photochromic element, wherein the photochromic body is formed on the metal substrate. 2. The photochromic element according to claim 1, wherein a surface of the metal substrate on a side on which the photochromic body is formed is subjected to a roughening treatment. The photochromic device according to claim 1, wherein the metal substrate includes a metal plate and a ceramic layer. A substrate made of metal or glass or ceramic;
A composite oxide film composed of a composite oxide of tin oxide and magnesium oxide and having a transparent conductive film whose optical transmission characteristics are changed by ultraviolet irradiation; a photochromic body formed on the substrate;
A photochromic device comprising a reinforcing layer bonded to the substrate. On the first substrate, a photochromic body having a composite oxide film composed of a composite oxide of tin oxide and magnesium oxide and having a transparent conductive film whose optical transmission characteristics are changed by ultraviolet irradiation is formed.
Bonding the photochromic body to a second substrate;
A method for producing a photochromic element, comprising separating the photochromic body from the first substrate.

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