Identifier, identifier matching method, and identifier matching device.

Abstract

The present invention provides an identifier that is extremely difficult to replicate and can be manufactured at relatively low temperatures using a substrate with poor heat resistance. [Solution] The identifier 51 comprises a substrate 55 with a normal operating heat resistance temperature of 500°C or less, and a thin film 53 provided on the surface of the substrate 55, which is transparent and has a porous spinodal structure.

Description

Technical Field

[0001] The present invention relates to an identifier, an identifier matching method, and an identifier matching device.

Background Art

[0002] In recent years, porous glass has attracted attention, and taking advantage of its excellent characteristics, industrial material applications such as adsorbents, microcarrier carriers, separation membranes, and optical materials are expected. Conventionally, as a method for relatively easily manufacturing porous glass, a method using the phase separation phenomenon of the glass itself is known.

[0003] The history of porous glass is old, and it began with the development of porous Vycor glass from a mother glass of a three-component composition system of SiO2 - B2O3 - Na2O by Corning Inc. in the United States in the 1940s (see, for example, Non-Patent Document 1).

[0004] The above-mentioned porous glass is produced by subjecting a glass of the SiO2 - B2O3 - Na2O composition system to heat treatment at 500°C to 700°C to cause phase separation into a part rich in SiO2 and a part rich in B2O3 - Na2O in the glass solid solution, and then immersing it in an acid solution to dissolve and remove the acid-soluble part rich in B2O3 - Na2O to make it porous (see Figure 6).

[0005] Conventionally, one-dimensional codes and two-dimensional codes have been attached to objects to identify the objects. However, one-dimensional codes and two-dimensional codes may be copied and misused. Therefore, an authentication system using porous glass having a spinodal phase separation structure as an individual authentication medium for an artifact metric is known (see Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] Using porous glass with a spinodal phase separation structure makes it extremely difficult to duplicate individual authentication media (identifiers). However, conventional porous glass with a spinodal phase separation structure requires high-temperature heat treatment to achieve phase separation. This presents a problem in that porous deposits cannot be placed on substrates or components with poor heat resistance, such as synthetic resin substrates.

[0008] The present invention has been made in view of the above problems, and aims to provide an identifier that is extremely difficult to replicate and can be manufactured at a relatively low temperature using a substrate with poor heat resistance, a method for matching this identifier, and an identifier matching apparatus for this identifier. [Means for solving the problem]

[0009] An identifier according to an aspect of the present invention is an identifier having a substrate with a normal operating heat resistance temperature of 500°C or less, and a thin film provided on the surface of the substrate, which is transparent and has a porous spinodal structure.

[0010] In the identifiers relating to the aspects of the present invention, the substrate is formed in a flat plate shape, the outer diameter of the substrate is between 0.05 mm and 5 mm, the thin film has a constant thickness, and covers at least a portion of one surface in the thickness direction of the substrate, or at least a portion of both surfaces in the thickness direction of the substrate.

[0011] An identifier matching method according to an aspect of the present invention is an identifier matching method comprising: a first measurement step of measuring the shape of the identifier; a storage step of storing the shape of the identifier measured in the first measurement step; a second measurement step of measuring the shape of the identifier described in claim 1 or claim 2, separately from the measurement in the first measurement step; an identifier shape determination step of comparing the shape of the identifier stored in the storage step with the shape of the identifier measured in the second measurement step and determining whether the shape of the identifier stored in the storage step and the shape of the identifier measured in the second measurement step match each other; and an output step of outputting the determination result from the identifier shape determination step.

[0012] An identifier matching device according to an aspect of the present invention is an identifier matching device having: a storage unit that stores the shapes of identifiers described above in advance; a measurement unit that measures the shape of a predetermined identifier; an identifier shape determination unit that compares the shape of the identifier stored in the storage unit with the shape of the identifier measured by the measurement unit and determines whether the shape of the identifier stored in the storage unit and the shape of the identifier measured in the measurement step match each other; and an output unit that outputs the determination result from the identifier shape determination unit. [Effects of the Invention]

[0013] The present invention provides an identifier that is extremely difficult to replicate and can be manufactured at a relatively low temperature using a substrate with poor heat resistance, as well as a method for matching this identifier and an apparatus for matching this identifier. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows a method for forming a porous deposit (thin film) according to an embodiment of the present invention. [Figure 2] This figure schematically shows a structure (identifier) ​​having a porous membrane obtained by a porous deposit formation method according to an embodiment of the present invention. [Figure 3] This is an SPM observation image of the surface of a porous deposit formed by the porous deposit formation method according to an embodiment of the present invention. [Figure 4] It is a diagram for explaining the principle of sputtering. [Figure 5] It is a diagram showing a simplified form of the thin film of the identifier according to an embodiment of the present invention. [Figure 6] It is a diagram showing the installation mode of the identifier according to an embodiment of the present invention on an article. [Figure 7] (a) is an enlarged view of part VII in FIG. 6, and (b) is a view taken in the direction of arrow VIIB in (a). [Figure 8] It is a block diagram showing a schematic configuration of an identifier collation device according to an embodiment of the present invention. [Figure 9] It is a flowchart showing an identifier collation method according to an embodiment of the present invention. [Figure 10] It is a SEM observation image of a porous deposit formed by the method for forming a porous deposit according to an embodiment of the present invention. (a) is a SEM observation image of the same surface as in FIG. 3, and (b) is a SEM observation image of a cross section (a cross section by a predetermined plane orthogonal to the surface).

Mode for Carrying Out the Invention

[0015] A structure 1 provided with a porous film serving as an identifier 51 according to an embodiment of the present invention will be described while referring to FIG. 2(b). The porous film is obtained by a method for forming a porous deposit. Details of the method for forming the porous deposit will be described later.

[0016] The structure 1 provided with the porous film is formed, for example, in a plate shape such as a flat plate shape, and includes a transparent base material (substrate) 3 made of a synthetic resin and a porous thin film (porous deposit; porous glass film) 5.

[0017] The porous glass film 5 is transparent and has a spinodal structure, and is provided on the surface of the substrate 3. The structure 1 provided with the porous film can be, for example, not only the identifier 51 but also an anti-fog member, a hydrophilic member, or an anti-fog / hydrophilic member.

[0018] Here, a method for manufacturing the structure 1 provided with the porous membrane (a method for forming the porous deposit 5) will be described.

[0019] The porous glass membrane (porous glass film) 5 is formed through a phase separation deposit installation process (phase separation thin film installation process) and a second phase removal process.

[0020] The phase separation deposit installation process is a process using a physical vapor deposition method (e.g., sputtering) with a phase-separating mother glass (see Fig. 1(a)) as a raw material (material; raw material; solid-phase raw material). Further, the phase separation deposit installation process is a process of providing (forming a thin film 11 on the surface of the base material 3) a deposit (phase-separating glass film) 11 phase-separated into a first phase (silicon oxide-rich phase) 7 and a second phase (non-silicon oxide-rich phase) 9 on the surface of the substrate 3 (see Fig. 1(b), Fig. 2(a)). When sputtering is employed as the physical vapor deposition method, the "raw material" can be referred to as a "target".

[0021] As the phase-separating mother glass (phase-separating mother glass), for example, bicomponent glass can be cited. In the phase-separating mother glass, each component constituting it is dispersed almost uniformly. The silicon oxide-rich phase 7 and the non-silicon oxide-rich phase 9 are, of course, generated from the target and are composed of the components of the phase-separating mother glass. The phase-separating glass film 11 is provided, for example, on one surface in the thickness direction of the substrate 3.

[0022] In the phase separation deposit installation process, the target, the deposit 11, and the substrate 3 are not particularly heated. Even when the temperatures of the target, the deposit 11, and the substrate 3 rise in the phase separation deposit installation process, the temperatures of the target, the deposit 11, and the substrate 3 do not exceed 500°C. In some cases, an etching inhibition layer may be formed on the surface of the thin film after the execution of the phase separation deposit installation process. When the etching inhibition layer is formed, the etching inhibition layer is removed by an etching inhibition layer removal process using alkali treatment with sodium hydroxide or the like.

[0023] The second phase removal step is a step in which the non-silicon oxide-rich phase 9 of the deposit 11 provided in the phase separation deposit installation step is removed, for example by etching, to form a porous glass film 5 (see Figure 1(c)). Note that in Figure 1(c), the second phase removal step is indicated as the third step.

[0024] In areas where the non-silicon oxide-rich phase 9 was present, many small spinodal voids 13 (see Figure 2(b)) were formed. These voids 13 give the sediment 11 a porous form, resulting in a porous thin film (porous glass film) 5.

[0025] Furthermore, after removing the non-silicon oxide-rich phase 9 in the second phase removal step, the substrate 3 and the porous glass film 5 may be washed (a washing step may be provided). That is, the substrate 3 and the porous glass film 5 may be subjected to water treatment washing. By undergoing water treatment washing, the non-silicon oxide-rich phase 9 and the like are removed even more reliably, and a porous glass film 5 having a silicon oxide framework is obtained.

[0026] Furthermore, the above-described method for forming porous deposits may be understood as a method for installing porous deposits on a substrate, a method for forming a porous glass film, a method for manufacturing an anti-fogging member, or a method for manufacturing a hydrophilic member.

[0027] Furthermore, as is already understood, in all steps of the porous deposit formation method, even if the temperature of the deposit 11 and the substrate 3 rises, the temperature of the deposit 11 and the substrate 3 will not exceed 500°C.

[0028] Here, we will explain the phase-separated sediment installation process (explaining that it is possible to install a sediment 11 separated into a first phase and a second phase without requiring heat treatment).

[0029] Figure 4 schematically illustrates the process by which sputtering particles reach the substrate and a thin film grows. The details are shown below.

[0030] The incident atoms collide with the substrate; some are reflected, and others are adsorbed.

[0031] Adsorbed atoms diffuse across the substrate surface, undergoing two-dimensional collisions with other atoms to form clusters (aggregates of atoms), or they remain on the surface for a certain period of time and then re-evaporate.

[0032] Clusters repeatedly collide with surface-diffusing atoms or undergo single-atom re-emission, but they begin to grow once the number of atoms exceeds a certain critical value.

[0033] The growing clusters continue to grow through the capture of surface-diffusing atoms, and merge with adjacent clusters to form a continuous film (Growth model of thin film).

[0034] Atoms adsorbed on the substrate surface collide with each other or are captured at positions with high adsorption energy, forming clusters. Therefore, surface diffusion of adsorbed atoms is an important process in thin film growth (see Susumu Kanehara, Yasuhiro Shiraki, and Sadashi Yoshida: Thin Film Engineering, Maruzen Co., Ltd. (2003) pp. 29-30).

[0035] Conventional techniques utilize thermal energy (substrate heating or heat treatment) to control phase changes such as amorphous or crystalline states through surface diffusion.

[0036] In physical vapor deposition processes, including sputtering, the gas (incident atoms = particles) temperature TG is often relatively higher than the substrate temperature TS (TG > TS). As a result, the high-temperature particles that reach the substrate are rapidly cooled on the substrate surface and frozen in that state.

[0037] However, at high substrate temperatures, these temperature differences become smaller, bringing the material closer to thermal equilibrium. This facilitates the movement of atoms within the grown thin film, making it possible to create a state with low free energy, similar to that of the bulk material.

[0038] In other words, when randomly incoming particles precipitate from a gas to a solid, they obtain thermal energy from the substrate and undergo surface diffusion, forming a structure according to thermodynamic principles. This surface diffusion proceeds more rapidly with greater thermal energy, leading to a phase change from an amorphous structure to a highly crystalline structure.

[0039] However, in recent years, inorganic functional materials such as oxides are often deposited on organic substrates that have poor heat resistance, and in many cases, the substrate temperature, which is one of the important parameters for phase change control, cannot be effectively manipulated. Therefore, in this invention, we focused on the kinetic energy of incident atoms (particles) as a new energy source for phase change control that replaces substrate temperature, i.e., thermal energy.

[0040] In the phase-separated deposit installation process, particles ejected from the target collide with surrounding gas particles as they travel towards the substrate, and upon reaching the substrate with a certain amount of kinetic energy, they undergo surface diffusion.

[0041] The thin film material deposited on the substrate is constantly exposed to particles that reach the substrate with kinetic energy. However, the decay process of the kinetic energy of these particles upon reaching the substrate transfers energy to the growing thin film, influencing its phase change, similar to thermal energy. By appropriately controlling this kinetic energy, material movement can be achieved without the need for heat treatment, thereby realizing a phase-separated structure.

[0042] Here, we will explain in more detail the phase-separating matrix glass (see Figure 1(a)) used in the formation method of porous sediment 5.

[0043] The phase-separated matrix glass is obtained by mixing 50.0 wt% (Mass%) to 70.0 wt% of volcanic ash, 15.0 wt% to 35.0 wt% of boron oxide (B2O3), 1.0 wt% to 8.0 wt% of sodium oxide (Na2O), 1.0 wt% to 8.0 wt% of lithium oxide (Li2O), 0 wt% to 6.0 wt% of magnesium oxide (MgO), 0 wt% to 5.0 wt% of calcium oxide (CaO), 0.3 wt% to 5.0 wt% of potassium oxide (K2O), and unavoidable impurities so that the total amount is 100 wt%. This mixture is then melted (melted at 1000°C to 1500°C for 1 to several hours until it becomes syrupy), and then cooled to vitrify.

[0044] In other words, the phase-separable matrix glass is obtained using a raw material composition obtained by mixing shirasu (volcanic ash) with boron, lithium, and at least one or more group 1 elements (such as Na or K) and group 2 elements (such as Mg or Ca). This phase-separable matrix glass is manufactured by known methods and processed into a target state suitable as a sputtering material.

[0045] Shirasu refers to a white to grayish-white, sandy material found in some areas of Kyushu, primarily originating from the Ito pyroclastic flow that occurred approximately 27,000 years ago during the eruption of the Aira Caldera (present-day inner part of Kagoshima Bay). In the area around Kagoshima Bay, the shirasu deposits are several tens to 200 meters thick, and the estimated reserves are 75 billion cubic meters. 3 It is estimated to be this much.

[0046] Shirasu has weaker compaction and higher water permeability compared to typical soils. Although there are some differences depending on the origin, shirasu is mainly composed of volcanic glass (about 70%), and also contains feldspar and quartz. It also contains magnetite and peridotite. Natural glass rocks are classified into obsidian, perlite, and pitchstone depending on the water content in the glass, but the volcanic glass in shirasu contains 3 wt% water, which is equivalent to that of perlite. Its chemical composition also shows values ​​close to that of perlite. Regarding the glass content, thermogravimetric analysis suggests that it forms a network structure characteristic of amorphous materials. On average, the chemical composition of shirasu contains about 70% silicic acid and about 14% alumina, as well as alkali metal oxides, alkaline earth oxides, and iron oxides.

[0047] Furthermore, the phase-separated matrix glass may be produced without using shirasu (volcanic ash). For example, the phase-separating matrix glass may be prepared by mixing 50.0 wt% to 70.0 wt% silicon dioxide (SiO2), 15.0 wt% to 40.0 wt% boron oxide (B2O3), 1.0 wt% to 8.0 wt% sodium oxide (Na2O), 1.0 wt% to 8.0 wt% lithium oxide (Li2O), 0.3 wt% to 5.0 wt% potassium oxide (K2O), a mixture of 0.1 wt% to 3.0 wt% magnesium oxide (MgO), calcium oxide (CaO), and aluminum oxide (Al2O3), and unavoidable impurities, so that the total amount is 100 wt%. This mixture may then be melted (melted at 1000°C to 1500°C for 1 to several hours until it becomes syrupy), and then cooled to vitrify.

[0048] In other words, the phase-separable matrix glass may be obtained using a raw material composition obtained by mixing at least one group 1 element (such as Na or K) component and a group 2 element (such as Mg or Ca) component with a lithium component and an aluminum component in an SiO2-B2O3-Na2O composition system.

[0049] In the aforementioned mixtures of magnesium oxide, calcium oxide, and aluminum oxide ranging from 0.1 wt% to 3.0 wt%, the proportions of magnesium oxide, calcium oxide, and aluminum oxide are arbitrary. For example, a mixture of magnesium oxide, calcium oxide, and aluminum oxide can be obtained using 0.5 wt% magnesium oxide, 0.6 wt% calcium oxide, and 0.1 wt% aluminum oxide (in this case, the mixture will have a total content of 1.2 wt%).

[0050] Furthermore, in the above mixture, at least one of magnesium oxide, calcium oxide, or aluminum oxide may be present in a 0 wt% amount. For example, the above mixture may consist of 0.5 wt% magnesium oxide, 0.0 wt% calcium oxide, and 0.0 wt% aluminum oxide. In this case, the expression "mixture" cannot be used, but in this specification, this case will also be included as a "mixture."

[0051] Because the phase-separated matrix glass has the composition described above, the silicon oxide-rich phase 7 becomes a region rich in SiO2 in the glass solid solution, and the non-silicon oxide-rich phase 9 becomes a region rich in B2O3-Na2O in the glass solid solution.

[0052] Then, by removing the non-silicon oxide-rich phase 9 of the phase-separable glass film 11 in the second phase removal step (for example, by etching), the porous glass film 5 shown in Figure 2(b) is formed.

[0053] As described above, the substrate 3 and the porous deposit 5 are transparent (including translucent and colored transparent). The porous deposit 5 is formed as a thin film as described above and is integrally provided on the substrate 3 on at least one surface in the thickness direction of the substrate 3, covering at least one surface in the thickness direction of the substrate 3. The thickness direction of the substrate 3 and the thickness direction of the thin film of the porous deposit 5 coincide with each other.

[0054] The transparency (visible light transmittance) between the porous deposit 5 and the substrate 3, which are integrated with each other, should be such that it appears almost transparent to the naked eye (similar to the transparency of a car's windshield), and it is desirable that it be, for example, 80% or higher.

[0055] Furthermore, the substrate 3 is made of a material with a normal operating temperature (continuous use temperature) of 500°C or less, or, for example, a synthetic resin. The substrate 3 may also be made of a material with a heat resistance temperature of 500°C or less, or a synthetic resin.

[0056] Incidentally, in the method for forming porous deposits, the substrate 3 may be made of a material with a normal operating heat resistance temperature (continuous use temperature) of 500°C or higher (more preferably a material with a normal operating heat resistance temperature of 700°C or higher), and a heating phase separation step may be added.

[0057] The heating phase separation step is performed after the deposit 11 has been placed in the phase separation deposit placement step and before the second phase 9 has been removed in the second phase removal step. In this step, the deposit 11 and the substrate 3 are heated (heated at a temperature of 500°C to 700°C for 1 to several hours) to further separate the phases of the deposit 11.

[0058] In other words, the heating phase separation process is performed to supplement the phase separation of the sediment 11 if the phase separation of the sediment 11 is insufficient.

[0059] Thus, if the phase separation of the deposit 11 is promoted by heating the deposit 11 and the substrate 3 after the deposit 11 has been placed in the phase separation deposit placement process, a deposit 11 that has been phase-separated into a silicon oxide-rich phase 7 and a non-silicon oxide-rich phase 9 can be more reliably placed on the substrate 3. In some cases, an etching-inhibiting layer may be formed on the thin film surface after heating. If an etching-inhibiting layer is formed, it is removed by an etching-inhibiting layer removal process using an alkaline treatment with sodium hydroxide or the like.

[0060] According to the method for forming the porous deposit 5, in the phase-separated deposit installation step, a deposit 11 separated into a silicon oxide-rich phase 7 and a non-silicon oxide-rich phase 9 is installed on the surface of the substrate 3 by sputtering targeting a phase-separated matrix glass. This makes it possible to install the porous deposit 5 on the substrate 3, which has poor heat resistance.

[0061] In other words, by using the sputtering method, phase separation can be performed without heating or at low temperatures below 500°C. This allows the porous deposit 5 to be placed on the substrate 3 by the kinetic energy of the particles (particles that separate from the target and constitute the deposit 11) without raising the temperature of the substrate 3. Furthermore, the porous deposit 5 can be placed on a substrate 3 made of synthetic resin or the like. This is expected to increase the range of materials that can be selected for the substrate 3 and broaden the range of applications, and will also be advantageous in terms of the added complexity of the manufacturing process and cost.

[0062] Furthermore, conventionally, there has been a demand to lower the heating temperature for phase separation due to the added manufacturing process and cost considerations. In addition, with anti-fogging materials, it is currently difficult to maintain excellent anti-fogging performance over a long period of time, and there are concerns about their weak durability against friction such as mechanical abrasion of the surface.

[0063] In contrast, according to the structure 1 equipped with a porous membrane according to an embodiment of the present invention, phase separation is performed in the phase separation deposit installation process by no heating or low-temperature heat treatment, thereby obtaining water absorption (porosity due to phase separation effect) and surface wettability (hydrophilization due to hydroxyl groups (OH groups) on the surface). Note that the number of OH groups decreases with heating.

[0064] Furthermore, according to the structure 1 equipped with a porous membrane according to an embodiment of the present invention, it is possible to form a porous glass membrane 5 on a substrate 3 with poor heat resistance by performing phase separation by no heating or low-temperature heat treatment. The porous glass membrane 5 formed after the phase separation deposit installation step and the second phase removal step has many voids (spaces) 13 and contains a large amount of hydroxyl groups. As a result, it has both excellent water absorption and hydrophilicity, so it can maintain excellent anti-fogging performance for a long period of time, and furthermore, the durability against friction such as mechanical rubbing of the surface of the porous glass membrane 5 is also increased.

[0065] To further explain, the hydrophilic / anti-fogging member 1 has a porous glass film 5. The porous glass film 5 has many pores 13 and contains a large amount of hydroxyl groups, so it has both excellent water absorption and hydrophilicity, which allows it to maintain excellent anti-fogging performance for a long period of time, and also has strong durability against friction such as mechanical rubbing of the surface. Note that hydroxyl groups are also present on the surface of the pores 13.

[0066] Furthermore, according to the structure 1 equipped with a porous membrane according to the embodiment of the present invention, since 50.0 wt% to 70.0 wt% of shirasu (volcanic ash) is used as the raw material for the phase-separating matrix glass, raw material costs can be kept low.

[0067] Here, with reference to Figures 3 and 10, the morphology of the porous glass film 5 according to the embodiment of the present invention will be described in detail. Figures 3 and 10 are images of the porous glass film 5 according to the embodiment of the present invention. Figure 3 is an image obtained by scanning probe microscopy (SPM) observation, and Figure 10 is an image obtained by scanning electron microscopy (SEM) observation.

[0068] In Figures 3 and 10, the darker areas (blackish areas) are where voids (pores) 13 are formed. The whitish areas other than the voids 13 are the skeleton (the flesh of the membrane). The diameter of the pores 13 is approximately 20 nm to 50 nm. The diameter of the skeleton is 100 nm or less (between 1 nm and 100 nm). As a result, the porous glass film 5 is almost transparent.

[0069] Incidentally, in the structure 1 equipped with a porous film, a block layer (not shown) may be provided between the substrate 3 and the porous thin film (porous glass film) 5 to prevent the diffusion of impurity components from the surface of the substrate 3. In the structure 1 equipped with a block layer, the block layer is in close contact with the surface of the substrate 3, and the porous glass film 5 is in close contact with the surface of the block layer, and the substrate 3, block layer, and porous glass film 5 are stacked in this order.

[0070] The block layer is formed, for example, from a thin film of silicon dioxide (SiO2). Furthermore, since the block layer is provided to prevent the diffusion of impurities from the substrate 3, it has a dense structure (a tightly packed structure; for example, a structure in which no open bubbles are present) that impurities cannot penetrate.

[0071] Furthermore, the block layer may contain other substances in addition to silicon dioxide, or may be composed of substances other than silicon dioxide, as long as it prevents the diffusion of impurity components from the surface of the substrate 3.

[0072] Furthermore, if the substrate 3 and the porous glass film 5 are transparent, the block layer is also transparent to avoid impairing visibility. If, after the deposit 11 is placed in the phase separation deposit placement process, the deposit 11 and the substrate 3 are heated in the heating phase separation process to further separate the phase of the deposit 11, the block layer is also made heat-resistant.

[0073] By providing a block layer, the diffusion of impurities into the porous glass film 5 is suppressed, and the hydrophilicity and other properties of the porous glass film 5 can be further improved.

[0074] Furthermore, regarding the method for forming the porous deposit, the block layer may be provided in the block layer installation step. In the block layer installation step, before the deposit 11 is provided on the surface of the substrate 3 in the phase-separated deposit installation step, the block layer is provided (film-formed) on the surface of the substrate 3 by, for example, a physical vapor phase growth method such as sputtering.

[0075] Furthermore, similar to the phase-separated deposit installation process, if the block layer is provided in the block layer installation process by a physical vapor phase growth method such as sputtering, the block layer is formed in the first half of the second step shown in Figure 1(b). Then, in the second half of the second step shown in Figure 1(b), the phase-separated deposit 11, consisting of a first phase 7 and a second phase 9, may be provided on the surface of the block layer.

[0076] Furthermore, although the above description uses a physical vapor deposition method such as sputtering to deposit the block layer in the block layer installation process, the block layer may be deposited by a method other than physical vapor deposition as long as it prevents the diffusion of impurity components from the surface of the substrate 3.

[0077] Next, an identifier 51 according to an embodiment of the present invention will be described. The identifier 51 is obtained by appropriately cutting the structure 1 to a predetermined size. The porous glass film 5 of the structure 1 becomes the thin film 53 of the identifier 51. The substrate 3 of the structure 1 becomes the substrate (surface) 55 of the identifier 51.

[0078] As shown in Figure 7, the identifier (authentication medium) 51 is composed of a substrate 55 with a normal operating heat resistance temperature of 500°C or less, and a thin film 53 provided on the surface of the substrate 55 that is transparent and has a porous spinodal structure. The substrate 55 is transparent, but the substrate 55 may also be opaque.

[0079] The voids 13 (see Figure 2(b)) within the porous thin film 53 are uniformly distributed within the porous thin film 53. Furthermore, as described above, a blocking layer (not shown) may be provided between the substrate 55 and the porous thin film 53 to prevent the diffusion of impurity components from the surface of the substrate 55.

[0080] In the thin film 53 with identifier 51, the morphology of the thin film 53 differs in the longitudinal, transverse, and thickness directions. Specifically, in the thin film 53 with identifier 51, the shape of the fine skeleton (muscle) of the thin film 53 and the fine pores (voids) 59 (see Figures 2(b), 3, 10, and 5) that are not part of the muscle 57 of the thin film 53 differs.

[0081] The morphology of the thin film 53 will be further explained with reference to Figure 5. In Figure 5, for the sake of explanation, the voids 59 of the thin film 53 are represented as grooves 61. The actual thickness of the thin film 53 in identifier 51, including the walls 57 and voids 59, is more complex than what is shown in Figure 5. The direction perpendicular to the plane of the paper in Figure 5 is the thickness direction of the thin film 53.

[0082] The solid line 63 in Figure 5 shows a groove 61 on the surface of the identifier 51 (the planar surface of the thin film 53 that is closest to the viewer). The areas other than this groove 61 are the fleshy parts 57 of the thin film 53. The dashed line 65 in Figure 5 shows a groove 61 on a predetermined planar surface behind the surface of the thin film 53. The shape of the groove 61 shown by the solid line 63 and the groove 61 shown by the dashed line 65 in Figure 5 are different. In this way, the morphology of the thin film 53 differs not only in the longitudinal and transverse directions of the thin film 53, but also in the thickness direction of the thin film 53 (the direction perpendicular to the plane of the paper in Figure 5). Furthermore, even if a large number of identifiers 51 are manufactured, the shapes of the thin films 53 will differ from one another and will not match.

[0083] In contrast, two-dimensional codes only have black and white arrangements for identification in the vertical and horizontal directions. That is, two-dimensional codes can only hold information in the vertical and horizontal directions. In the thin film 53 of identifier 51 according to the embodiment of the present invention, information is held not only in the vertical and horizontal directions but also in the height direction (thickness direction). That is, the thin film 53 of identifier 51 can be used as a three-dimensional code.

[0084] Furthermore, while two-dimensional codes represent information using only two values ​​(white and black), identifier 51 can represent information using three or more values, including gray, in addition to white and black, because the shape of the thin film 53 is complex and light is reflected and refracted in a complex way. In addition to brightness (white, black, and gray), information can also be represented by hue and saturation.

[0085] Incidentally, the spinodal structure of conventional individual authentication media is made of porous material, which scatters light and appears white. As a result, even individual authentication media stabilized by resin encapsulation, etc., can be easily found. Furthermore, since conventional individual authentication media are bulk glass, the glass itself becomes the individual authentication media, making it difficult to attach individual authentication media to arbitrary substrates or components.

[0086] In contrast, because identifier 51 is transparent, it is not easy to determine where identifier 51 is located. That is, by thinning the spinodal structure and reducing the pore diameter and skeleton diameter to a predetermined size or smaller, the thin film 53 of identifier 51 becomes almost transparent despite being porous. Furthermore, the individual authentication medium of the spinodal structure thin film 53 is coated onto any substrate or component using the sputtering method. Thin films 53 produced by the sputtering method are generally hard and resistant to breakage. Moreover, even when the thin film 53 is applied to a flexible substrate 55, the thin film 53 is hard and small in size, making the thin film 53 (identifier 51) resistant to breakage.

[0087] Identifier 51 will be explained further. The base material 55 is formed in a flat plate shape (for example, a rectangular plate shape (more specifically, a square plate shape)). The thickness dimension of the base material 55 is a predetermined value within the range of, for example, 0.4 μm to 1 μm (more preferably 0.6 μm to 1 μm, and even more preferably 0.8 μm to 1 μm).

[0088] The outer diameter of the base material 55 is between 0.05 mm and 5 mm (more preferably between 0.1 mm and 2 mm, and even more preferably between 0.1 mm and 1 mm).

[0089] When the base material 55 is formed in the shape of a rectangular flat plate, the vertical dimension of the base material 55 is 0.05 mm to 5 mm (more preferably 0.1 mm to 2 mm, and even more preferably 0.1 mm to 1 mm).

[0090] Furthermore, if the base material 55 is formed in the shape of a rectangular flat plate, the horizontal dimension of the base material is also 0.05 mm to 5 mm (more preferably 0.1 mm to 2 mm, and even more preferably 0.1 mm to 1 mm).

[0091] Furthermore, the base material 55 may be formed in other shapes, such as a disc shape or a triangular shape, when viewed in the thickness direction.

[0092] The thin film 53 has a constant thickness and covers at least a portion (for example, the entire surface) of one surface of the substrate 55 in the thickness direction. Alternatively, the thin film 53 may have a constant thickness and cover at least a portion of both surfaces of the substrate 55 in the thickness direction (for example, the entire surface of one surface and the entire surface of the other surface).

[0093] The thickness dimension of the thin film 53 is, for example, a predetermined value within the range of 0.05 μm to 3 μm (more preferably 0.1 μm to 1 μm, and even more preferably 0.1 μm to 0.4 μm). In an embodiment in which the entire surface of the substrate 55 in the thickness direction is covered with the thin film, the vertical dimension of the thin film 53 is equal to the vertical dimension of the substrate 55, and the horizontal dimension of the thin film 53 is equal to the horizontal dimension of the substrate 55.

[0094] Furthermore, identifier 51 is so small that it is almost impossible to perceive its presence with the naked eye.

[0095] Here, the method for matching identifier 51 (identifier matching method) will be explained with reference to Figure 9. The identifier matching method comprises a first measurement step S1, a storage step S3 (storage unit), a second measurement step S5, an identifier shape determination step S7, and an output step S9.

[0096] In the first measurement step S1, the shape of the identifier 51 (thin film 53) is measured. As part of the measurement in the first measurement step S1, the thin film 53 of identifier 51 may be photographed using a camera or other imaging device (not shown) with visible light. Examples of visible light include sunlight or light emitted from lighting fixtures. It is also possible to use a single wavelength of light with the shortest possible wavelength, such as 400 nm, as the visible light. Furthermore, electromagnetic waves with a shorter wavelength than visible light, such as ultraviolet light, may be used instead of visible light.

[0097] Furthermore, in the above imaging, for example, the optical axis of the camera lens is approximately perpendicular to the surface of the thin film 53 of identifier 51 (the plane located on the opposite side of the plane in the thickness direction of the substrate 55), and the optical axis passes through approximately the center of the surface of the thin film 53 of identifier 51. In addition, in the above imaging, images of the muscle tissue 57 of the thin film 53 and the voids 59 that are not muscle tissue of the thin film 53 (for example, the grooves 61 shown by the solid line 63 in Figure 5) that exist on the surface of the thin film 53 of identifier 51 are obtained.

[0098] Furthermore, the above imaging method also allows us to obtain images of the morphology of the voids 59 and other structures behind the thin film 53, which can be seen through the voids 59 (voids present on the surface of the thin film 53) of the thin film 53. In addition, since the fleshy part 57 of the thin film 53 is transparent or semi-transparent, we can also obtain images of the morphology of the voids 59 and other structures that can be seen through the fleshy part 57 of the thin film 53.

[0099] Furthermore, computed tomography using electromagnetic waves such as X-rays may be employed as the first measurement step. In addition, computed tomography using sound waves such as ultrasound may be employed instead of or in addition to electromagnetic waves. The shape of the flesh portion 57 and voids 59 of the thin film 53 may be obtained as three-dimensional data.

[0100] In the memory step S3, the shape of the identifier 51 (thin film 53) measured in the first measurement step S1 (data relating to the shape of the flesh portion 57 and the void 59) is stored.

[0101] Furthermore, the identifier 51 that is the object of measurement in the first measurement step S1 may be one, or there may be two or more.

[0102] If there is only one identifier 51 to be measured, the storage step stores the shape of the single identifier 51 measured in the first measurement step. If there are multiple identifiers 51 to be measured, the first measurement step S1 is repeated, and measurement is performed for each of the multiple identifiers 51 in the first measurement step S1. The storage step stores the shape of each of the multiple identifiers 51.

[0103] The second measurement step S5 is performed, for example, after the storage step S3 is completed. The second measurement step S5 measures the shape of an identifier (for example, one identifier) ​​separately from the measurement in the first measurement step S1.

[0104] The identifier to be measured in the second measurement step S5 may be an identifier manufactured by the manufacturing method described above, or it may be an identifier manufactured by a manufacturing method other than the manufacturing method described above.

[0105] Furthermore, the identifier to be measured in the second measurement step S5 may be the identifier 51 that was measured in the first measurement step S1, or it may be an identifier that was not measured in the first measurement step S1. The measurement in the second measurement step S5 is performed in the same manner as the measurement in the first measurement step S1.

[0106] In the identifier shape determination step S7, the shape of the identifier 51 stored in the storage step S3 is compared with the shape of the identifier 51 measured in the second measurement step S5. It is then determined whether the shape of the identifier 51 stored in the storage step S3 and the shape of the identifier 51 measured in the second measurement step S5 match each other. In the output step S9, the determination result from the identifier shape determination step S7 is output.

[0107] If the shapes of multiple identifiers 51 are stored in the storage step S3, the identifier shape determination step S7 determines whether the shape of one identifier 51 measured in the second measurement step S5 matches the shape of one of the multiple identifiers 51 stored in the storage step S3.

[0108] Then, if a match is found, output step S9 outputs a message indicating that a match was found; if no match is found, output step S9 outputs a message indicating that no match was found.

[0109] It is difficult to perfectly match the shooting conditions in the first measurement step S1 with those in the second measurement step S5. Therefore, the matching in the identifier shape determination step S7 determines the difference between the shape of the identifier stored in the storage step S3 and the shape of the identifier captured in the second measurement step S5. When this difference is within a predetermined small range, it is determined that the shape of the identifier stored in the storage step S3 and the shape of the identifier captured in the second measurement step S5 match.

[0110] Here, we will explain the case where the identifier 51 is installed on article 77 (see Figure 6). Let's take a branded bag as example of article 77. The identifier 51 is installed in a predetermined location on article 77. When the identifier 51 is installed on article 77, it is desirable that the identifier 51 is covered with a protective film (a protective film that is transparent to visible light) 79, as shown in Figure 7. Alternatively, the protective film 79 may be opaque to visible light, and the protective film 79 may have the same color or pattern (protective color) as other parts of the surface of article 77 (parts other than the protective film).

[0111] By assigning identifier 51 to item 77, it can be used as a substitute for the serial number (manufacturing number) of item 77 (branded goods), creating a market structure that only includes genuine products and expanding the business. Furthermore, it can simplify the distribution of goods in pawn shops in areas where counterfeits are rampant and help eliminate the counterfeiting business.

[0112] Here, the identifier matching device (identifier matching device) 67 for identifier 51 will be described with reference to Figure 8. The identifier matching device 67 is used, for example, when performing a matching method for identifier 51.

[0113] The identifier matching device 67 is comprised of a storage unit (shape data storage unit) 69, a measurement unit (identifier measurement unit) 71, a shape discrimination unit (identifier shape discrimination unit) 73, and an output unit 75. The storage unit 69 and the identifier shape discrimination unit 73 are composed of, for example, a CPU and memory. The measurement unit 71 is composed of, as described above, an imaging device such as a camera. The output unit 75 is composed of, for example, an LCD.

[0114] The measuring unit 71 is configured to measure the shape of a predetermined identifier 51. The storage unit 69 has pre-stored the shape of the identifier 51. For example, the storage unit 69 stores the shape of the identifier 51 measured by the measuring unit 71. The storage unit 69 may also be configured to store the shape of the identifier 51 measured by a measuring unit other than the measuring unit 71.

[0115] The identifier shape determination unit 73 compares the shape of the identifier 51 stored in the storage unit 69 with the shape of the identifier 51 measured by the measurement unit 71. It then determines whether the shape of the identifier 51 stored in the storage unit 69 and the shape of the identifier 51 measured by the measurement unit 71 match each other. The output unit 75 outputs the determination result from the identifier shape determination unit 73.

[0116] In identifier 51, a transparent, porous, spinodal film 53 is provided on the surface of a substrate 55 with a normal operating heat resistance temperature of 500°C or less. This allows identifier 51 to be manufactured at a relatively low temperature using a substrate 55 with poor heat resistance, and also makes it extremely difficult to replicate identifier 51.

[0117] Furthermore, while conventional spinodal structures have considerable potential as individual authentication media for artificial object metrics, their porous structure causes light to scatter and become white. This hinders their application to components requiring visibility and design aesthetics, and because the authentication confirmation area is white, it is easy to identify the location where the individual authentication media is set, which may lead to security concerns.

[0118] Here, we will further explain the case where the identifier 51 is installed on the item 77. In this case, for example, the output unit 75 is an input / output unit (for example, a touch panel), and unique information such as the serial number of the item 77 is input from the input / output unit. Then, the shape of the identifier 51 and the unique information of the item 77, such as the serial number of the item 77, may be associated and stored in the storage process (storage unit 69).

[0119] Furthermore, if the identifier shape determination unit 73 determines that the shape of the identifier 51 stored in the memory unit 69 matches the shape of the identifier 51 measured by the measurement unit 71, it may output a statement indicating that they match and unique information.

[0120] In identifier 51, the thin film is transparent and has a porous spinodal structure. Since the thin film is produced at a temperature of 500°C or less, light scattering is less likely to occur and whitening is less likely to occur, unlike conventional individual authentication media.

[0121] Furthermore, identifier 51 is extremely difficult to duplicate and possesses both high security and visibility, making it a valuable tool for the brand industry, which is struggling with the circulation of counterfeit goods.

[0122] The identifier 51 is so small that its presence cannot be easily recognized with the naked eye. As a result, even if the identifier 51 is attached to the article 77, it becomes difficult to find where the identifier 51 is attached to the article 77. This makes it even more difficult to duplicate the identifier 51.

[0123] The identifier matching method includes a storage step S3 for storing the shape of the identifier 51 measured in the first measurement step S1. The identifier matching method also compares the shape of the identifier 51 stored in the storage step S3 with the shape of the identifier 51 measured in the second measurement step S5. Finally, an identifier shape determination step S7 determines whether the shapes of the identifiers 51 match.

[0124] This makes it easy to determine whether the article 77 to which the identifier 51 is attached is genuine or counterfeit. Furthermore, if the shape of the identifier 51 stored in the storage process S3 is three-dimensional data, the identifier 51 cannot be duplicated, so it is possible to reliably determine whether the article 77 to which the identifier 51 is attached is genuine or counterfeit.

[0125] Incidentally, in addition to installing the identifier 51 on the article 77, another identifier, separate from the identifier 51, may be installed on the article 77 at a designated location on the article 77 (for example, a conspicuous location such as the base of the handle of a branded bag 77). As the other identifier, a one-dimensional identifier such as a barcode that can be read by a commercially available reader, or a two-dimensional code such as a QR code (registered trademark), may be used.

[0126] Furthermore, the identifier matching device 67 may store in advance in its memory the above-mentioned other identifier and the location on which the identifier 51 is installed on the article 77, in association with each other. In this way, when the above-mentioned other identifier of the article 77 is read, the location on the article 77 where the identifier 51 is installed may be output, for example, by the output unit 75 of the identifier matching device 67.

[0127] Although this embodiment has been described above, this embodiment is not limited to these, and various modifications are possible within the scope of the gist of this embodiment. [Explanation of Symbols]

[0128] 51 Identifier 53 Thin films (glass films; porous thin films) 55 Base material 67 Identifier Verification Device 69 Memory section 71 Measurement Unit 73 Identifier Shape Discrimination Unit 75 Output section S1 First measurement process S3 storage process S5 Second measurement process S7 Identifier shape discrimination process S9 Output process

Claims

1. A substrate with a normal operating heat resistance temperature of 500°C or less, A thin film provided on the surface of the substrate, which is transparent and has a porous spinodal structure, An identifier containing the following elements.

2. The substrate is formed in a flat plate shape, The outer diameter of the aforementioned substrate ranges from 0.05 mm to 5 mm. The identifier according to claim 1, wherein the thin film has a constant thickness and covers at least a portion of one surface in the thickness direction of the substrate, or at least a portion of both surfaces in the thickness direction of the substrate.

3. A first measurement step of measuring the shape of the identifier described in claim 1 or claim 2, A storage step for storing the shape of the identifier measured in the first measurement step, A second measurement step, separate from the measurement in the first measurement step, is to measure the shape of the identifier described in claim 1 or claim 2, An identifier shape determination step involves comparing the shape of the identifier stored in the storage step with the shape of the identifier measured in the second measurement step, and determining whether the shape of the identifier stored in the storage step and the shape of the identifier measured in the second measurement step match each other. An output step that outputs the discrimination result in the identifier shape discrimination step, A method for matching identifiers having the following characteristics.

4. A storage unit that pre-stores the shape of the identifier described in claim 1 or claim 2, A measuring unit that measures the shape of a predetermined identifier, An identifier shape determination unit compares the shape of the identifier stored in the storage unit with the shape of the identifier measured by the measurement unit, and determines whether the shape of the identifier stored in the storage unit and the shape of the identifier measured in the measurement step match each other. An output unit that outputs the discrimination result from the identifier shape discrimination unit, An identifier matching device having

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