JP2017121699A - Stress luminescent card - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stress luminescent card which has a function of emitting light when receiving stress, and which is hard to be counterfeited.SOLUTION: Provided is a stress luminescent card 10 in which a transparent base material 3 and an opaque base material 4 are overlapped, and which comprises a light-emitting medium 1 which emits light by stress. The light-emitting medium 1 has a flat top face 6, and is provided with an opening of a prescribed size on an undersurface 7 opposite to the top face 6 and a recess 2 which is so formed as to have a prescribed depth from the undersurface 7 in a thickness direction. The light-emitting medium 1 is sandwiched between the transparent base material 3 and the opaque base material 4 in such a manner that the top face 6 is directed to the transparent base material 3 side.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a card that emits light when stress is applied.

  Stress luminescence, which is luminescence due to mechanical external forces such as compression, tension, friction, shear, and impact, has been studied. Then, the “material” itself that generates stress luminescence, that is, the “material composition” or “material structure” has a “potential light-emitting structure”, and only by applying a relatively small stress, A “stress luminescent material” having a novel “luminescence” mechanism capable of causing the “material” to emit light has been discovered.

Typical examples of emission centers include strontium aluminate added with europium (SrAl ₂ O ₄ : Eu: green emission), zinc sulfide added with manganese as the emission center (ZnS: Mn, yellow-orange emission), and the like. Yes (see Patent Document 1). Then, these stress luminescent materials are made of the structure itself (all the structures are composed of “stress luminescent materials”) or a laminate in which the structure is simply stacked on another structure, etc. In addition, those in which an external stress is directly applied to the structure and the structure or the laminate is simply caused to emit light are disclosed (see Patent Document 2).

JP 2007-55144 A JP 2003-253261 A

  However, in the above conventional technique, a stress light emitting structure alone or a simple laminate is formed, and external stress is applied to them to simply cause the stress light emitting structure or laminate to emit light. . Therefore, it is easy to forge without producing a stress-stimulated luminescent structure and producing a structure that obtains the same effect without great difficulty.

  Accordingly, an object of the present invention is to provide a stress light emitting card that has a function of emitting light by applying stress, but is difficult to forge.

In order to solve the above problems, in the first aspect of the present invention,
A stress light-emitting card comprising a light-emitting medium, which is a medium that emits light by stress, wherein a transparent base material and an opaque base material are superimposed,
The light emitting medium has a flat surface on one side, an opening having a predetermined size on the other surface facing the one surface, and a predetermined thickness direction from the other surface in the thickness direction. Having a recess formed in depth;
The light emitting medium is provided with a stress light emitting card, wherein the light emitting medium is sandwiched between the transparent substrate and the opaque substrate so that the one surface faces the transparent substrate.
Here, the term “flat surface” means that the shape of the surface is visually recognized as having no particular dent or protrusion and forming a uniform surface.

  According to the first aspect of the present invention, the stress light-emitting card includes a light-emitting medium in which a transparent base material and an opaque base material are overlapped and emits light by stress, and the light-emitting medium has a flat one surface. And having an opening of a predetermined size on the other surface opposite to the one surface, and having a recess formed at a predetermined depth in the thickness direction from one surface, The luminescent medium is sandwiched between a transparent base and an opaque base so that one side faces the transparent base, so it is difficult to counterfeit while having the function of emitting light by applying external stress. It becomes possible to obtain a stress-stimulated light emitting card.

  In the second aspect of the present invention, the depth of the concave portion is 5/10 to 9/10 (5/10 or more and 9/10 or less) of the thickness of the light emitting medium. .

  According to the second aspect of the present invention, since the depth of the recess is 5/10 to 9/10 of the thickness of the light emitting medium, the other facing the one surface of the light emitting medium on the side to be visually recognized. Even in the concave portion formed by providing an opening on the surface side, it becomes possible to emit light that is more clearly visible from the one surface side through the transparent substrate.

  In the third aspect of the present invention, the tip of the concave portion in the thickness direction is linear (straight or curved).

  According to the third aspect of the present invention, since the tip end portion of the concave portion in the thickness direction is linear, the stress concentration factor is increased, and a stronger light is emitted when stress is applied to the luminescent medium. It becomes possible.

  Further, the fourth aspect of the present invention is characterized in that the opening is arranged on the one surface as constituting a predetermined pattern.

  According to the fourth aspect of the present invention, since the openings of the recesses are arranged as constituting a predetermined pattern on the surface of the light emitting medium on the side of the transparent substrate, the predetermined information is expressed by light emission. And forgery prevention effect is enhanced.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the stress light emission card | curd which is difficult to forge while providing the function to add external stress and to light-emit.

It is a perspective view which shows an example of the luminescent medium used by this invention. It is the top view and sectional drawing which show the luminescent medium used by this invention. It is a perspective view which shows the stress light emission card | curd which concerns on one Embodiment of this invention. It is the top view and sectional drawing of the stress light emission card | curd which concern on one Embodiment of this invention. It is a top view of the light emission medium in the case of expressing predetermined information by light emission. It is the top view and sectional drawing which show the example from which the luminescent medium used by this invention differs.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
<1. Luminescent medium>
FIG. 1 is a perspective view showing an example of a light emitting medium used in the present invention. In FIG. 1, 1 is a light emitting medium, 2 is a recess, 6 is an upper surface, and 7 is a lower surface. The luminescent medium 1 is obtained by firing a composition containing a stress luminescent material, and has a predetermined thickness D. In the example of FIG. 1, six concave portions 2 are formed in the light emitting medium 1. The thickness D can be set as appropriate, but is preferably 10 μm to 300 μm. This is because if the thickness is less than 10 μm, it is not possible to form a sufficiently large recess for increasing the emission intensity. On the other hand, when the thickness exceeds 300 μm, the light emission intensity does not increase with respect to the thickness, and the use efficiency of the stress light emitting material is low. However, the upper limit of the thickness is limited by the thickness of the card when embedded in the card as will be described later.

  FIG. 2 is a plan view and a cross-sectional view showing a light emitting medium according to an embodiment of the present invention. 2 (a) is a partial plan view seen from the lower surface side, FIG. 2 (b) is a cross-sectional view corresponding to line AA in FIG. 2 (a), and FIG. 2 (c) is FIG. It is sectional drawing corresponding to the BB line of (a). In FIG. 2, 1 is a light emitting medium, 2a is an opening edge, 2b is a tip, 6 is an upper surface, and 7 is a lower surface. In addition, although there is no distinction between upper and lower in the light emitting medium, in the present embodiment, for convenience of explanation, the flat surface on the side where the opening of the recess 2 is not formed is the upper surface 6 (one surface, FIG. 2B). The upper surface in (c) and the surface on which the opening of the recess 2 is formed will be described as the lower surface 7 (the other surface, the lower surface in FIGS. 2B and 2C). The light emitting medium 1 has a rectangular parallelepiped shape having a predetermined thickness D, and an upper surface 6 and a lower surface 7 which are surfaces having the largest area face each other. If the upper surface 6 is one surface, the lower surface 7 facing the upper surface 6 can be said to be the other surface.

  The perspective view of FIG. 1 and the cross-sectional view of FIG. 2B are mainly for explaining the structure of the recess 2, and therefore the ratio of the planar direction to the thickness direction is different from the actual one. Actually, the width of the light emitting medium 1 is several tens mm to several hundreds mm, whereas the thickness of the light emitting medium 1 is several hundred μm or less. Although the same applies to FIG. 1, the actual opening area of the recess 2 is significantly smaller than the area of the upper surface of the light-emitting medium 1, but the ratio is not considered in FIGS. 1 and 2 for convenience of explanation. It shows.

  In the luminescent medium 1, the upper surface where the opening of the recess 2 is not formed is a flat surface. Here, the term “flat surface” means that the shape of the surface is visually recognized as having no particular dent or protrusion and forming a uniform surface. Therefore, it is not necessarily limited to a theoretical plane, and in a visible range (however, in the present invention, since it is embedded in a card as will be described later, it is not actually observed), all over a certain three-dimensional curved surface. This includes curved surfaces where the tangent lines are the same or change gently. That is, a microscopic surface such as the surface of a “plate-shaped ground glass” is microscopically uneven, but a surface that is visually recognized as a flat surface is also a “flat surface”. Even if the “ground glass” itself has a shape that forms a three-dimensional curved surface such as “rice cake”, the surface is included in the “flat surface” of the present invention.

  Since the luminescent medium used in the present invention has such a “form”, when a “predetermined external force load” is applied to the luminescent medium, the generated “light of a predetermined wavelength” "Dull light" with a distinctive texture from the inside of the "flat surface" (meaning that no special irregularities or other features can be found by visual inspection). It is possible to observe. More precisely, such a “flat surface” refers to the surface roughness in the “roughness curve” excluding the “waviness curve” in the “surface roughness evaluation method” defined in JIS standards. It means that Ra is 0.01 to 1.0 μm (more preferably 0.01 to 0.50 μm). If the surface roughness Ra exceeds the upper limit value, “light of a predetermined wavelength” that passes through the “flat surface” is strongly scattered and the visibility thereof is lowered. It is very difficult to make the thickness Ra less than 0.01 μm because of the properties of the “stress luminescent material” described in detail below.

  The light-emitting medium 1 is preferably translucent in order to observe “dull light” in which the portion to shine is not specified when viewed from the upper surface 6 side (one surface side which is a flat surface). Here, “semi-transparent” means that the transmittance of D-rays of sodium atoms is 30% or more and 80% or less. When the transmittance is 30% or more and 80% or less, the light emitted from the embedded light-emitting medium 1 becomes “dull light” having a unique texture.

  As shown in FIGS. 1 and 2A, the shape of the opening edge 2a, which is the edge of the opening of the recess 2, is a rectangle. As shown in FIGS. 1 and 2, the recess 2 has a shape that is triangular in the AA cross section and rectangular in the BB cross section. For this reason, the front-end | tip part 2b used as the deepest part of the recessed part 2 becomes a linear form of predetermined length, as shown to Fig.2 (a) (c). When the tip portion 2b is a straight line, the stress concentration factor α is the highest, but the stress concentration factor α is high even in a state where the tip portion 2b is connected by a curved line instead of a straight line. That is, the stress concentration coefficient α increases due to the presence of vertices that are both ends of a straight line or a curve.

  When a predetermined stress is applied to the light emitting medium 1 from a predetermined angle (tensile, bending, or twisting), the load is transmitted to the light emitting medium 1 directly or indirectly, and the tip of the recess 2 is formed. Stress concentrates at two points on both ends of the part 2b, and the concentrated part emits light. For example, when a load of about several MPa is applied to the luminescent medium 1 in a direction orthogonal to the plane, in a direction twisting the plane, or in a pulling direction, a visible level of luminescence is exhibited in the stress concentration portion. To do. Furthermore, the anti-counterfeiting property is improved by changing the direction of the stress load so that different light emission patterns appear.

  In the luminescent medium 1, “tensile stress”, “shear stress”, “displacement stress” or the like (“internal stress” or “deformation stress” is caused by “deformation accompanied by physical movement” generated in the luminescent medium 1. ”, And“ Stress ”, classified from“ Symptom plane ”). The concave portion 2 is a portion where “stress concentration degree is 2 or more” when those stresses are generated, that is, a portion where “stress concentration coefficient α corresponding to those stresses is 2 or more”. It is.

  The position of the recess 2, particularly the tip 2 b, which is the “part having the largest stress concentration coefficient α”, changes depending on the direction of deformation in the light emitting medium 1 and the magnitude and direction of the external force applied. The stress-stimulated luminescent material composing the luminescent medium 1 has an intensity proportional to the “magnitude of“ stress ”and a“ structure (composition, crystal structure, etc. constituting the stress-stimulated luminescent material ”described in detail below. .) "Emits light of a wavelength specific to the structure (inherent) with an intensity corresponding to the" direction of stress ". The strength corresponding to the “direction in which the stress acts” means “strength corresponding to the deformation stress”. That is, the “stress magnitude” generated varies depending on the “three-dimensional direction of stress applied to the three-dimensional structure of the material such as the crystal structure”, and the “luminescence intensity” varies accordingly.

The “light having a wavelength peculiar to“ the structure constituting the stress-stimulated luminescent material ”” is “light having a predetermined wavelength”, and is usually in a visible light wavelength range, that is, a wavelength of light of 400 nm to 800 nm. In this range, light of one wavelength is emitted corresponding to one kind of stress luminescent material. Therefore, the observer can visually recognize the emitted “light of a predetermined wavelength”. However, the intensity of the “light of a predetermined wavelength” is at least 1.0 mcd / cm ² (mm) as the light emission luminance (one index of “light intensity”) in order to be visually recognized. A size of candela / square centimeter is required. Light emission by the light emitting medium 1 is 10 mcd / cm ² or more, and even when embedded in a card, it can be visually recognized through a transparent substrate.

In the present invention, the “stress luminescent material” is a material that easily undergoes “twinned pseudoelastic deformation” when stress is applied to the material in the vicinity of the so-called “thermoelastic martensitic transformation”. A light having a predetermined wavelength when stress is applied to the material with physical deformation, represented by “Eu-added SrAl ₂ O ₄ (also referred to as“ SAOE ”)”, etc. , And the light emission intensity increases in accordance with the applied stress ”.

  The recess 2 shown in FIGS. 1 and 2 is a so-called “wedge” recess. The “wedge shape” means that one side surface (one rectangle) of a triangular prism is positioned on the outermost surface, and the other two side surfaces (two rectangles) and the upper and lower surfaces (two triangles) of the triangular prism are It is a shape that forms the “four surfaces” of the indented part, and is formed by two triangular (cross-sectional) surfaces and three parallel sides connecting the three vertices. Is located at the opening (opening edge 2a), and the other side is defined as being located at the bottom of the dent (tip 2b).

  For example, for a “basic shape” of 20 mm long × 30 mm wide × 30 μm (0.03 mm) in thickness, a “wedge shape” is formed on the other surface (lower surface 7) opposite to one surface (upper surface 6) which is a flat surface. When the concave portion 2 which is a concave portion with “” is provided, a shape like the “light emitting medium 1” in FIG. 2 is obtained. Here, FIG. 2 shows an example in which only six concave portions 2 having the same triangular prism shape are arranged in an orderly manner, but actually, depending on the purpose of use of the luminescent medium 1, Various changes can be made. Specifically, the shape (three-dimensional shape) and size of each recess 2 and the direction of the tip 2b (in the example of FIGS. 1 and 2, the tip 2b is a straight line, but a line connecting two points. As long as it has a shape, it may be a curved line), the shape of the opening (not only rectangular but also other planar shapes), size, orientation (vertical and horizontal direction of the opening), number of recesses 2 The arrangement of the recesses 2 (not only an orderly arrangement but also a random arrangement, or an arrangement for displaying a predetermined pattern) may be variously changed. When the shape of the opening is a rectangle and the ratio of the length of the short side to the long side is large, the light emission intensity distribution varies depending on the direction in which the stress is applied.

  When a predetermined external load is applied to the recess 2, that is, when deformation is applied in the direction of opening the “two sides of the opening edge 2 a”, the stress concentration coefficient α at the tip 2 b, which is the other side, is equal to 2 or more. And at the same time the maximum. Further, the smaller the “opening angle” (corresponding to the apex angle of the triangle) at the tip 2b is in the range of 10 to 90 degrees, the stress concentration coefficient α increases. When the opening angle is less than 10 degrees, the stress concentration factor α can be extremely increased. However, in the manufacturing process of the luminescent medium 1 including the firing step, the manufacturing stability is insufficient and it is difficult to withstand repeated deformation. It becomes.

  Further, the value of the stress concentration coefficient α at the tip 2b varies depending on the direction in which the deformation is applied. That is, the value fluctuates depending on the direction in which a predetermined external load is applied. For example, when the above-described “triangular prism triangle” is deformed in an opening direction, the stress concentration coefficient α at the distal end portion 2b is increased in the distal end portion 2b. Stress concentrates on the point.

  That is, the recess of the recess 2 is a single three-dimensional vector that is added to the “wedge shape” and is determined by the “direction in the three-dimensional space” of the predetermined external force load (the ratio of each size of the three-dimensional space component). The “light emission intensity (or distribution thereof)” and the “light emission point position (or light emission region)” change. This means that the “direction” in the three-dimensional space (the “external force”) of the predetermined external force load applied to the light-emitting medium 1 provided with the concave portion 2 with respect to the light-emitting medium 1 and thus the “wedge-shaped” concave portion 2 is The light emission state (position distribution of light emission points and intensity distribution of individual light emission points) varies depending on the direction of the vector expressed by “three-dimensional vector”.

  It is also preferable to determine the authenticity by changing the direction of the predetermined external force load with respect to the light emitting medium 1 and visually checking the change in the light emitting state of the light emitting medium 1. As the concave shape of the concave portion 2, a “wedge shape with a rectangular bottom surface”, that is, a “wedge trapezoidal shape”, a polygonal pyramid such as a quadrangular pyramid and a pentagonal pyramid, a cone, an elliptical cone, and an “opening shape” Also included are polygons such as triangles and quadrangles, circles, ellipses, and deformations thereof. In addition, as the concave shape of the concave portion 2, the bottom surface of the concave, such as a semi-cylindrical concave shape, a semi-ellipsoidal concave shape, a hemispherical concave shape, and combinations thereof, is a “dent” having a “three-dimensional curved surface shape”. Is also included. Of course, it is also preferable that the “dent shape” be an “arbitrary three-dimensional curved surface” on the premise that the shape can be controlled (meaning that there is manufacturing reproducibility).

  The depth of the concave portion 2 is, for example, 5/10 to 9/10 of the thickness D of the light emitting medium 1 when provided on a part of the surface of the light emitting medium 1 having a “flat (sheet-like)” outer shape. It can be depth. In addition, the shape of the concave portion 2 is a so-called socket function for reflecting the light from the light source and condensing the light emitted from the tip portion 2b which is the bottom (of the “concave reflector”). It plays a role in this way) and improves the light condensing property and directivity to improve the light visibility.

  The shape of the recess 2 is a shallow bottom, for example, the depth of which is less than 1/10 of the thickness D of the light emitting medium 1, and the ratio of [(opening width / depth) ] Of 20/1 or more, even if stress concentration occurs around the tip 2b, which is the bottom of the recess 2, the stress concentration coefficient α is less than 2. In addition, the shape of the recess 2 has a shallow bottom, and particularly when the depth is less than 5/10 of the thickness D of the light emitting medium 1, the bottom surface 7 on which the opening of the recess 2 is formed. It becomes difficult to visually recognize light emission from the opposite upper surface 6 side. Further, a shape having a deep bottom, in particular, a depth of more than 9/10 to less than 10/10 of the thickness D of the light emitting medium 1 is very close to the periphery of the tip 2b which is the bottom of the recess 2. Although a large stress concentration occurs, the tip 2b is likely to crack due to repeated deformation operations. Therefore, in the case of a deep shape, “stable light emission of at least 100 times” cannot be ensured, and it becomes difficult to ensure reliability as a forgery prevention medium.

  In order to manufacture the luminescent medium 1 made of a predetermined stress luminescent material, first, a cavity (“mold” is formed in which one surface is a flat surface and the other surface has a protrusion corresponding to the recess 2. ) Means a space inside “).) Is prepared in advance. Then, a “composition containing a stress-stimulated luminescent material” before firing is filled into the cavity of the mold, and the filler (before firing) and the mold are simultaneously heated to a predetermined temperature using predetermined means, and And heating at a predetermined heating rate. And after holding at a predetermined temperature for a predetermined time, it is also cooled at a predetermined cooling rate using a predetermined means, and when it approaches near room temperature, the filling (after firing) is taken out from the mold. Procedure (This is the “firing” procedure. After “pre-firing” in air, which is an oxidizing atmosphere, adding “molding” treatment to this, then “main firing” in a reducing atmosphere, etc. Is also a “baking” procedure and is preferred.

  Here, the firing mold is a “mold” made of ceramics or metal, and the target object (before firing) is poured into and filled in the mold, and the mold is subjected to predetermined conditions. The fired filler is taken out of the mold, and a “baked object (after firing)” having a predetermined shape and having a predetermined composition is obtained.

  The shape of the cavity of the firing mold is a shape in which a protrusion for forming the recess 2 (wedge shape in the example of FIGS. 1 and 2) is formed. That is, it has a shape having a portion where the stress concentration coefficient α is at least 2 or more. In addition, the shape of the cavity is determined in consideration of material shrinkage during firing. However, in actuality, in this cavity, a “predetermined hydroxide or the like that becomes the light-emitting medium 1 by predetermined firing” described below is diluted with a predetermined solvent (including an aqueous solvent) to obtain fluidity. A so-called pouring gate (an opening for filling the composition into the cavity; also referred to as a “fluid port”) for pouring the “composition containing the stress-stimulated luminescent material before firing” at a predetermined pressure. After firing, the portion corresponding to the gate is cut and smoothed (to make the portion a smooth surface as if there was no gate). (The same applies to the air vent and the portion (connector) that connects the individual baked products in multi-sided firing.)

  Further, the cavity inside the firing mold has a “shape in which a protrusion for forming the recess 2 is formed (hereinafter also referred to as“ predetermined shape ”)”. In order to obtain such a mold for firing, a numerical product is obtained from a molded product such as an appropriate plastic material provided with a desired shape by a molding means, or a predetermined shape is cut out (3D data produced by CAD). An NC machine that produces a three-dimensional object in a three-dimensional manner while controlling the coordinate position with a cutting machine tool and a so-called ultra-precise machine tool is precise and preferable. ), A wet etching method (including resist treatment), a dry etching method (including an energy beam etching method), a plastic material or the like obtained from a formed material (meaning shaved), and Is a method for obtaining the above-mentioned firing mold comprising a predetermined material composition by performing molding or firing using the molded product or the formed product as a molding mother die or a firing mother die. Used.

  Furthermore, using the above-described firing mold, a composition containing a stress-stimulated luminescent material which is in a molten state and has fluidity is allowed to flow into the cavity of the firing mold, and the cavity is completely filled. After that (vacuum suction or the like may be performed), the light emitting medium 1 made of a stress light emitting material having a predetermined shape may be obtained by rapid cooling or gradually cooling. At this time, as a condition for rapid cooling or gradual cooling, a condition is selected in which the volumetric shrinkage due to the cooling of the stress-stimulated luminescent material becomes smaller.

  In addition, the light emitting medium 1 can be obtained by a molding means from such a molding die or using such a firing die as a molding die. In particular, when such a molding means is employed, a mixture of “stress luminescent particles” and “transparent resin” (further containing an appropriate solvent) is filled in the cavity of the molding die. It is preferable to do. The “mold” used in such a mold or firing mold is an open mold having a high molding load and an opening, and is molded or fired in a closed space with a relatively low molding load. The former “mold” includes a press mold or a forging mold, and the latter “mold” includes an injection mold, a compression mold, and a casting mold. , Glass molds, powder molds (“molds” for forming powders by injection molding). Among these, the “casting mold” includes an open mold and a closed mold. Further, a “die casting mold” in which the melt is poured directly into the “mold”, or a mold for pouring the melt is formed. There is a "raw sand mold". Any of these is preferable because there is little change in the shape of the cavity after taking the “mold” and the shape after firing.

  When using this casting mold as a molding mold or firing mold, mix the particles of stress-stimulated luminescent material and a transparent resin (adjusted fluidity by adding an appropriate solvent) and mold with “mold” (Used as “molding mold”. The added solvent is evaporated.) Further, after the molding, the molded product is fired (sintered) under predetermined conditions (“fired mold”). Used to remove the transparent resin.) More specifically, the stress-luminescent material particles are 60 to 90% by mass and the transparent resin is 40 to 10% by mass (100% by mass as a whole) to obtain a molded product. Alternatively, after the molding is fired (sintered), the transparent resin is set to “approximately 0% by mass”, and the stress density of the stress luminescent material is 98% by mass or more.

<2. Stress light emitting card>
FIG. 3 is a perspective view showing a stress light-emitting card according to an embodiment of the present invention. In FIG. 3, 1 is a light emitting medium, 3 is a transparent substrate, 4 is an opaque substrate, 5 is a transparent substrate, and 10 is a stress light emitting card. The light emitting medium 1 is sandwiched between the transparent base material 3 and the opaque base material 4 and is in a state of being incorporated inside the stress light emitting card 10. In FIG. 3, the outer shape of the luminescent medium 1 is indicated by a broken line. When applying a stress light-emitting card to a plastic card that is also used in the credit card standard, the transparent base materials 3 and 5 are also called oversheets, and are laminated with an opaque base material 4 also called a core sheet. Is done.

  FIG. 4 is a plan view and a cross-sectional view of a stress light-emitting card according to an embodiment of the present invention. 4A is a plan view seen from above, and FIG. 4B is a cross-sectional view corresponding to the line CC in FIG. 4A. In addition, although the stress light emitting card is originally not upside down, in this embodiment, for convenience of explanation, the transparent base material 3 in which the light emitting medium 1 is embedded is formed as an upper layer (upper side in FIG. 4B), and the other side. The transparent base material 5 side will be described as the lower layer (the lower side in FIG. 4B). The perspective view of FIG. 3 and the cross-sectional view of FIG. 4B are mainly for explaining the layer structure of the stress light emitting card 10, and therefore the ratio of the planar direction to the thickness direction is different from the reality. Actually, the thickness of the stress light emitting card 10 is several mm or less, while the width of the stress light emitting card 10 is several cm to several tens of cm. Although the same applies to FIG. 3, the actual opening area of the recess 2 is significantly smaller than the area of the upper surface of the light emitting medium 1 and the stress light emitting card 10. Shown without considering the ratio. When the stress light emitting card 10 is viewed from the upper surface, the light emitting medium 1 is translucent and the transparent base material 3 is transparent, but the opening of the concave portion 2 is formed on the lower surface. It is difficult to see. In the plan view of FIG. 4A, the recessed portions 2 (opening edge portion 2a, tip portion 2b) that are difficult to see when viewed from the upper surface side are indicated by broken lines.

  Various structures can be used as the stress light emitting card 10. In this embodiment, the stress light emitting card 10 has a three-layer structure including a transparent base material 3, an opaque base material 4, and a transparent base material 5. The transparent substrates 3 and 5 are both formed of a transparent soft vinyl chloride sheet. The opaque base material 4 is formed of a milky white opaque hard vinyl chloride sheet. The thicknesses of the transparent substrates 3 and 5 are all 100 μm, and the thickness of the opaque substrate 4 is 560 μm. By sandwiching and laminating the opaque base material 4 having a thickness of 560 μm between the transparent base materials 3 and 5 having a thickness of 100 μm, a three-layer laminated vinyl chloride sheet that also conforms to the JIS standard (credit card size) can be obtained.

  When laminating, the light emitting medium 1 is embedded between the transparent base material 3 and the opaque base material 4 by sandwiching the light emitting medium 1 between the transparent base material 3 and the opaque base material 4. The heat applied at the time of lamination is adjusted between the melting points of the transparent substrate 3 and the opaque substrate 4. Thereby, the transparent base material 3 side which is a soft vinyl chloride sheet melts, and the opaque base material 4 side which is a hard vinyl chloride sheet hardly melts. Therefore, as shown in FIG. 4B, the light emitting medium 1 is incorporated into the stress light emitting card 10 so as to be embedded on the transparent substrate 3 side.

  As the transparent substrate 3, polyethylene terephthalate, polycarbonate, polypropylene resin, PET-G (non-crystalline copolyester resin), or the like is preferably used. In the present embodiment, a transparent soft vinyl chloride sheet is used. Here, the term “transparent” means that the D-ray transmittance of sodium atoms is 80% or more. When the transmittance is 80% or more, light emission from the embedded light-emitting medium 1 is easily visible from the transparent substrate 3 side. In addition, as the opaque base material 4, polyethylene terephthalate, polycarbonate, polypropylene resin, PET-G, or the like is preferably used, but in the present embodiment, an opaque hard vinyl chloride sheet is used. Here, the term “opaque” means that the D-ray transmittance of sodium atoms is 30% or less. When the transmittance is 30% or less, light emission from the embedded light-emitting medium 1 becomes difficult to visually recognize from the transparent substrate 5 side.

  The recesses 2 formed in the light emitting medium 1 are arranged on the lower surface 7 of the light emitting medium 1 as constituting a predetermined pattern. And predetermined information can be expressed by the predetermined pattern comprised by arrangement | positioning of the recessed part 2. FIG. FIG. 5 is a plan view of a light emitting medium when predetermined information is expressed by light emission. The example of FIG. 5 shows an example in which 23 recesses 2 are formed in a state in which the left and right recess groups of 2 rows × 5 columns are connected by three recess groups. The structure of the recess 2 itself is the same as that shown in FIGS. As shown in FIG. 5, when the light emitting medium 1 emits light by applying stress by arranging it so that the rectangular opening edge 2 a is positioned on the lower surface 7 (side in contact with the opaque base material 4), The letter “H” which is a predetermined pattern can be visually recognized.

  FIG. 6 is a plan view and a cross-sectional view showing a modification of the light emitting medium 1. 6A is a partial plan view as seen from the lower surface side, FIG. 6B is a cross-sectional view corresponding to the line EE of FIG. 6A, and FIG. 6C is FIG. It is sectional drawing corresponding to the FF line of (a). In FIG. 6, 2a is an opening edge part, 2b is a front-end | tip part.

  As shown in FIG. 6 (a), the opening edge 2a, which is the edge of the opening of the recess 2, is rectangular as in FIG. 2 (a), but the tip is not linear but exists on the same curved surface. ing. Moreover, as shown in FIG. 6, the recessed part 2 becomes a shape which becomes a semi-elliptical shape in the EE cross section, and becomes a rectangular shape in the FF cross section. Even in such a concave portion 2, the curved surface and the semicircular plane constituting the concave portion 2 have a higher stress concentration coefficient than other portions of the light emitting medium 1, and the stress concentration coefficient α ≧ 2. In the example shown in FIG. 6, the stress concentration coefficient is highest at the opening edge 2a. As the distance from the opening edge 2a increases, the stress concentration factor decreases rapidly.

As described above, the light emitting medium 1 includes a material that emits light by stress (stress light emitting material). As described above, the luminescent medium 1 can be formed by firing or the like. As such a stress-stimulated luminescent composition, a composition prepared by including a stress-stimulated luminescent material in a resin or the like can be used. As the stress-stimulated luminescent material, for example, a host material composed of one or more of oxides, sulfides, carbides and nitrides having an FeS ₂ structure described in JP 2000-63824 A was excited by mechanical energy. When electrons return to the ground state, a stress-stimulated luminescent material to which one or more emission centers of a rare earth or transition metal that emits light is added, or (A) a spinel structure MgAl ₂ O described in Japanese Patent Application Laid-Open No. 2000-119647. _In a base crystal of at least one metal oxide or composite oxide selected from ₄ and CaAl ₂ O ₄ , Al ₂ O _{3 having} a corundum structure, and SrMgAl ₁₀ O ₁₇ having a β-alumina structure, (B A small number selected from rare earth metal ions and transition metal ions having unstable 3d, 4d, 5d or 4f electron shells and capable of causing radiative transitions in the electron shells; Examples thereof include stress-stimulated luminescent materials made of a substance containing at least one kind of metal ion as the central ion of the luminescent center.

Further, as a stress-stimulated luminescent material, a carrier which is composed of at least one aluminate having a non-stoichiometric composition described in JP-A-2001-49251 and which is excited by mechanical energy returns to the ground state. A stress luminescent material comprising a substance having lattice defects that emit light, or a substance containing at least one metal ion selected from a rare earth metal ion and a transition metal ion as a central ion of a luminescent center in the base material; , CaYAl ₃ O ₇ , Ca ₂ Al ₂ SiO ₇ , Ca ₂ (Mg, Fe) Si ₂ O ₇ , Ca ₂ B ₂ SiO ₇ , CaNaAlSi ₂ O having a melilite structure described in JP-A-2001-64638 _{7, Ca 2 MgSi 2 O 7} , (Ca, Na) 2 (Al, Mg) (Si, Al) 2 O 7, and _{Ca 2 (Mg, Al) (} Al, i) in the base material consisting of one or more of the oxides of SiO _7, adding a luminescent center electrons excited by mechanical energy consist of more than one rare earth or transition metal that emit light when returning to a ground state The materials disclosed in the stress-stimulated luminescent material and the like can be used.

In addition, a fluorescent material can be used as the stress luminescent material. For example, strontium aluminate with europium added as the emission center (SrAl ₂ O ₄ : Eu, Sr ₃ Al ₂ O ₆ : Eu, green emission), zinc sulfide with manganese as the emission center (ZnS: Mn, yellow green) Light emission). The stress-stimulated luminescent material is present as particles in the composition, and the composition is fired to form the luminescent medium 1. In particular, it is possible to adjust the composition using a material in which a stress light-emitting material is dispersed in a highly transparent polymer resin in a so-called nanoparticle shape having a particle diameter of about 10 to 200 nm. This is preferably carried out because it can be improved and stabilized. Examples of the polymer resin in which the above-described stress-luminescent material of nanoparticles is dispersed include polymethyl methacrylate (PMMA) and epoxy resin.

<3. Example>
As a firing mold in which a cavity having “a form in which one surface is flat and a protrusion corresponding to the recess 2 is formed on the other surface” is provided in advance, the shape of the cavity is 20 mm long × 30 mm wide × It was formed for a basic shape with a thickness of 30 μm. Specifically, a concave portion 2 that is a “wedge” -shaped recess is provided on one surface of the basic shape, and the metal is fired in a “shape” as shown in FIG. A die for use Ka and a press die for providing the wedge-shaped recess 2 were prepared.

  Here, the “wedge shape” is a “shape” (a triangular prism shape having isosceles triangles facing each other) having a rectangular opening of 20 μm × 10 μm and a depth of 25 μm. Every other wedge shape is provided in a grid pattern with an interval of 10 μm. (In FIG. 1 and FIG. 2, six recesses 2 are shown.)

Separately, Sr ₃ Al ₂ O ₆ which is a base material is added with 1% by mass of Eu and 1% by mass of boric acid as a luminescent center, and a rectangular parallelepiped of 20 mm long × 30 mm wide × 30 μm thick is formed. 1 and 2 as described above by pressure molding with a 10-ton press after gradually heating up to 900 ° C. in a hydrogenated argon reducing atmosphere and pre-baking. 1 to 2 to obtain a presintered product of a stress-stimulated luminescent material having a shape as shown in FIGS. 1 and 2 (the firing mold Kb is separated into two upper and lower parts and used by being opened and closed. The detailed procedure for filling the firing mold Kb with “material” and the detailed procedure for taking out the “baked product” after firing are omitted.).

  This “preliminarily fired product of the stress-stimulated luminescent material” was replaced with the firing mold Ka prepared as described above, fired at 1300 ° C. for 4 hours in a hydrogenated argon reducing atmosphere, and naturally cooled. Then, taking out from the firing mold Ka, with respect to the “basic shape” of length 20 mm × width 30 mm × thickness 30 μm, one surface is a flat surface, and the other surface is A “wedge-shaped” recess as a predetermined portion “a concave portion 2 having a predetermined shape (a triangular prism shape having isosceles triangles facing each other)” (at least the tip portion in FIG. 2) 2b has a stress concentration coefficient α = 2.0 or more) provided in a “grid pattern” shape (provided in a jumping manner) to obtain the luminescent medium 1. (See FIGS. 1 and 2. FIG. 1 and FIG. 2 show “schematic diagrams” in which only six recesses 2 having the same triangular prism shape are arranged in an orderly manner.

Next, a milky white hard vinyl chloride sheet having a thickness of 0.56 mm is used as the opaque substrate 4, and a transparent soft vinyl chloride sheet having a thickness of 0.10 mm is used as the transparent substrates 3 and 5. The material 3, the light emitting medium 1, the opaque base material 4, and the transparent base material 5 were stacked in this order and press-laminated by applying hot pressure (120 ° C., 25 kg / cm ² , 10 minutes). Thereby, the stress light emission card | curd 10 as shown in FIG. 3, FIG. 4 was obtained. During press laminating, the soft transparent substrate 3 is melted out of the transparent substrate 3 and the opaque substrate 4 in contact with the luminescent medium 1 by heating, and the luminescent medium 1 is embedded in the transparent substrate 3. It became a state.

  Then, the three-dimensional image data of the shape of the stress light emitting card 10 of the embodiment is applied to “structural analysis software (stress distribution analysis software)”, and both ends of the stress light emitting card 10 in the lateral direction (left and right direction in FIG. 4) are in front. It was confirmed that it was a “shape having a part with a stress concentration coefficient α of 15.0” against the load of deformation stress to be curved so that the central part in the horizontal direction is pressed from the back to the back. .

  Next, according to the method of obtaining the bending characteristics of plastic (bending test method. JIS K 7171 2008, ISO 178 2003), “(Testing machine)” and “Testing method” are adopted. According to the three-point method, the surface (upper surface 6) on the transparent base material 3 side of the stress-stimulated light emitting card 10 of the example is directed downward, and the side where the concave portion 2 is not provided is directed downward. In the direction perpendicular to the surface as a predetermined external load with respect to the stress light emitting card 10 at a test speed of 2 mm / min so that both ends of the card are supported by fulcrums and the central part in the lateral direction is pushed down from the back side. When the deformation stress of 100 kPa is applied, the stress light emitting card 10 causes “deformation” that is bent (curved) in that direction, and the deformation stress concentrates on the front end portion 2b of the light emitting medium 1 and the same. A light having a predetermined wavelength (green light: 520 nm) having a light emission intensity corresponding to the deformation stress is emitted from the tip 2b, and the light having a predetermined wavelength (green light) is visible through the transparent substrate 3. It became.

  Specifically, “deformation stress” concentrates on the tip 2b of the light emitting medium 1, and the tip 2b emits light of a predetermined wavelength (green light) having emission intensity corresponding to the “deformation stress”. . In particular, strong light (green light) is emitted from the tip 2b, and the side surface of the recess 2 (the triangular surface of the “triangular prism” and the two side surfaces other than the opening. This is the so-called “illuminating light umbrella”. The light (green light) is collected in a certain direction and strengthened, and at the same time, the light is transmitted through the inside of the light emitting medium 1. The observer, on the “one surface” side corresponding to the position where the concave portion 2 of the light emitting medium 1 is provided, passes through the transparent base material 3, and the “predetermined wavelength light (green slightly diffused slightly). Light ") (see FIGS. 3 and 4. The deformed state and the light emitting state are not shown). The authenticity of the light emitting medium 1 was confirmed by this light emission. Furthermore, when this authenticity confirmation operation was repeated 100 times, none of them changed, and the same “green” light emission could be confirmed. Therefore, it is very difficult to forge the light emitting medium 1 of the embodiment. So I thought.

  The light emission principle at this time will be described. It is assumed that the light emitting medium 1 is curved with a predetermined external force load, for example, both ends (both ends in the long side direction) of the light emitting medium 1 sandwiched between the left and right fingers. At this time, the light-emitting medium 1, that is, the stress-stimulated luminescent material constituting the light-emitting medium 1 is deformed (bent) so as to “bend” in the curve direction according to the curve.

As a result, deformation stress concentrates on the tip 2b of the recess 2 of the light emitting medium 1 (one side of the bottom of the recess 2; stress concentration coefficient α = 10.0) (the average value σ _{0 of} stress on the tip 2b). “Maximum value of stress σmax” which is 10 times greater than “”. And the front-end | tip part 2b light-emits the light of the predetermined wavelength which has the light emission intensity according to the deformation stress, and strong light is discharge | released. This light is also reflected by the side surface of the recess 2 (meaning the inner wall of the recess), and the light is collected and strengthened in a certain direction. The side surface of the recess 2 serves as a so-called “illumination light umbrella”. The observer was able to visually recognize the light having the predetermined wavelength through the transparent substrate 3 at the position of the concave portion 2 on the surface of the light emitting medium 1 where the concave portion 2 is provided (see FIGS. 3 and 4). The deformed state and the light emitting state are not shown.)

Further, a predetermined external force load different from the above, for example, both ends of the light emitting medium 1 (both ends in the “short side” direction) are sandwiched between the left and right fingers, and the light emitting medium 1 is attached to the light emitting medium 1. Suppose it is curved. At this time, the light emitting medium 1, that is, the stress light emitting material constituting the light emitting medium 1 is deformed so as to “bend” in the bending direction according to the curve, and a deformation stress is applied to a predetermined portion of the light emitting medium 1. Concentrate (“Stress maximum value σmax” 15 times the “stress average value σ ₀ ” acts on that “side”). Unlike the above, the predetermined portion here is the “midpoint” (meaning the middle position) of the tip 2b of the recess 2 that is most deformed when bent, and the stress concentration coefficient α = 15. .0.

  And the front-end | tip part 2b light-emits the light of the predetermined wavelength which has the light emission intensity according to the deformation stress (especially strong light is discharge | released from the front-end | tip part 2b of the recessed part 2, and the side surface of the recessed part 2 is similar to the above. But it reflects and the light is collected and strengthened.) The observer, at the position corresponding to the midpoint of the tip 2b of the recess 2 on the upper surface of the light emitting medium 1 where the recess 2 is provided, passes through the transparent base material 3 with light of a predetermined wavelength (a little green). It was possible to visually recognize more intensely (light that spreads dimly) (see FIGS. 3 and 4. The deformed state and the light-emitting state are not shown).

  Further, when the concave portion 2 is formed in the arrangement as shown in FIG. 5, the stress light emitting card 10 has both ends in the plane direction and a force is applied so as to bend the card surface. The emission of the “H” shape constituted by the opening of the recess 2 was confirmed. Due to the presence of the opaque base material 4, light emission could not be confirmed from the transparent base material 5 side.

  Even in the case where the light emission by the light emitting medium 1 is confirmed in the stress light emitting card 10, the light emitting medium 1 cannot be easily removed because the light emitting medium 1 does not exist on the surface and is embedded. Moreover, even when it is going to counterfeit the stress light emission card | curd 10, the installation for embedding the light emission medium 1 is needed, and it becomes difficult to forge.

<4. Comparative Example>
In the example, in a firing mold Kb having a rectangular parallelepiped cavity of 20 mm in length × 30 mm in width × 30 μm in thickness, after being temporarily fired, “fired” is applied as it is to form a shape of 20 mm in length × 30 mm in width × 30 μm in thickness. It was set as the comparative example. When this comparative example was evaluated in the same manner as in the example, the entire light emitting medium emitted light evenly and slightly, but strong light emission at a specific position did not occur, and there was no particular dependence on the deformation direction. Such a luminescent medium was relatively easy and could be produced in large quantities in the same manner, and was considered insufficient for the purpose of preventing forgery.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made. For example, in the above embodiment, an example in which a transparent base material is laminated on both sides of an opaque base material has been described. However, a transparent base material is laminated only on one side where a light emitting medium of the transparent base material is formed. May be.

DESCRIPTION OF SYMBOLS 1 ... Luminous medium 2 ... Concave part 2a ... Opening edge part 2b ... Tip part 3, 5 ... Transparent base material 4 ... Opaque base material 6 ... Upper surface (one surface)
7 ... Lower surface (the other surface)
10 ... Stress light emitting card D ... Thickness (of the light emitting medium 1)

Claims (4)

A stress light-emitting card comprising a light-emitting medium, which is a medium that emits light by stress, wherein a transparent base material and an opaque base material are superimposed,
The light emitting medium has a flat surface on one side, an opening having a predetermined size on the other surface facing the one surface, and a predetermined thickness direction from the other surface in the thickness direction. Having a recess formed in depth;
The stress light-emitting card, wherein the light emitting medium is sandwiched between the transparent base and the opaque base such that the one surface faces the transparent base.   The stress light-emitting card according to claim 1, wherein a depth of the concave portion is 5/10 to 9/10 of a thickness of the light-emitting medium.   The stress light-emitting card according to claim 1, wherein a tip end portion of the concave portion in the thickness direction is linear.   The stress light-emitting card according to any one of claims 1 to 3, wherein the openings are arranged on the one surface as constituting a predetermined pattern.

Images