JP6167687B2 - Information recording medium and method for reading information recording medium - Google Patents

Description

  The present invention relates to an information recording medium capable of reading with infrared rays and a reading method thereof.

  In general printed matter such as tickets and lotteries, image information such as characters and barcodes is formed so that anyone can see it. Therefore, there is a possibility of being counterfeited or tampered with by others. Therefore, a technique has been proposed in which such image information is normally invisible.

  As an example of this, there is a method for preventing forgery by reading invisible image information using infrared rays. For example, Patent Document 1 describes that a latent image mark for the purpose of preventing counterfeiting is formed using a phosphor that is excited by visible light or infrared light and emits infrared light. Patent Document 2 describes that a phosphor that emits visible light when excited by infrared rays is printed on a document or the like to prevent forgery.

Japanese Patent No. 5143673 Japanese Patent No. 4315371

  However, since phosphors usually emit light only at the time of excitation, there is a need for special illumination in order to excite the phosphors at the time of reading in dark places such as night, darkness, and dark rooms where light does not reach. There is a problem that decreases.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an information recording medium and the like that can be easily read even in a dark place.

  According to a first aspect of the present invention for achieving the above object, a phosphorescent layer that is excited by excitation light and maintains a light emission state, and an infrared light emitting layer that is excited by light emitted from the phosphorescent layer and emits infrared light is used as a base material. An information recording medium characterized by being provided above.

  In the information recording medium of the first invention, the phosphorescent layer is excited by preliminarily irradiating sunlight or illumination light as excitation light, and the light emission state is maintained even after excitation. In the information recording medium, the infrared light emitting layer is excited by this light emission to emit infrared light. Since the phosphorescent layer maintains the light emitting state, the light emitting state of the infrared light emitting layer is also maintained. Therefore, the image information formed by the infrared light emitting layer can be read by infrared rays at night or in dark places where light does not reach, such as a dark room, which is highly convenient. In addition, the information recording medium has a simple configuration and does not require a dedicated light source for exciting the infrared light emitting layer at the time of reading, so the cost can be reduced.

In the information recording medium of the first invention, it is desirable that the luminous layer is formed on the base material and the infrared light emitting layer is formed on the luminous layer.
Thereby, reading with infrared rays can be performed with high accuracy.

Moreover, it is desirable that the infrared light emitting layer is formed by a pattern having a void.
In this case, since the excitation light directly reaches the phosphorescent layer from the gap of the infrared light emitting layer, the energy stored in the phosphorescent layer can be increased.

Alternatively, the infrared light emitting layer may be formed on the base material, and the phosphorescent layer may be formed on the infrared light emitting layer.
Also in this case, the excitation light reaches the phosphorescent layer directly, and the energy stored in the phosphorescent layer can be increased.

The luminous layer preferably emits visible light.
Accordingly, it is possible to determine the authenticity of the information recording medium by visually observing whether or not the phosphorescent layer is shining in a dark place, and there is an advantage that information can be read using infrared rays for authentication. Further, since reading by infrared rays can be performed by checking a portion where the phosphorescent layer is shining, the operation is also easy.

  According to a second aspect of the present invention, there is provided an information recording medium comprising: a phosphorescent layer that is excited by excitation light and maintains a light emission state; and an infrared light emitting layer that is excited by light emitted from the phosphorescent layer and emits infrared light. A method for reading an information recording medium, wherein the reading is performed by receiving infrared light emitted from the infrared light emitting layer excited by light emitted from the phosphorescent layer.

  According to the present invention, it is possible to provide an information recording medium that can be easily read even in a dark place.

The figure which shows the information recording medium 1 The figure which shows typically the example of the excitation spectrum and emission spectrum of the phosphor of the luminous layer 13 and the fluorescent substance of the infrared light emitting layer 15 The figure explaining the reading method of the information recording medium 1 The figure which shows the example which provided the infrared reader 23 in the housing | casing 25 The figure which shows the information recording medium 1a The figure which shows the information recording medium 1b

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
(1. Information recording medium 1)
FIG. 1 is a diagram showing an information recording medium 1 according to the first embodiment of the present invention, and shows a cross-sectional configuration of the information recording medium 1.

  As shown in FIG. 1, the information recording medium 1 is provided with a phosphorescent layer 13 and an infrared light emitting layer 15 on a substrate 11, the phosphorescent layer 13 is formed on the substrate 11, and on the phosphorescent layer 13. An infrared light emitting layer 15 is formed.

  In the information recording medium 1, the infrared light emitting layer 15 records image information that can be read by infrared rays and is difficult to see with the naked eye. The image information is not particularly limited, and examples thereof include various figures, symbols, numbers, characters, and other pictures, barcodes, two-dimensional codes, OCR numbers, OCR characters, and the like.

  The base material 11 is, for example, a paper material such as plain paper, but the material is not particularly limited, such as other plastics.

  The phosphorescent layer 13 is excited by irradiating ultraviolet light, visible light, or the like from illumination light such as sunlight, fluorescent lamps, and LEDs as excitation light, accumulates energy, and maintains a light emission state after excitation. It is a layer to contain. The phosphorescent layer 13 is formed by solid-printing a phosphorescent material mixed with a phosphorescent material, a resin, a viscosity adjusting solvent, and the like on the base material 11 by silk screen printing or the like. As the phosphor, for example, “N Luminous” (registered trademark) manufactured by Nemoto Lumi Material Co., Ltd. can be used, and once excited, it is possible to maintain a light emitting state for a long time. .

  The infrared light emitting layer 15 is a layer containing a phosphor that emits infrared light when excited by the light emitted from the phosphorescent layer 13. The infrared light emitting layer 15 is formed by solid printing a fluorescent material mixed with a phosphor, a resin, a viscosity adjusting solvent, and the like by silk screen printing or the like. The material used for the infrared light emitting layer 15 may be a phosphorescent material.

  The fluorescent material used for the infrared light emitting layer 15 may be a pigment or a dye, and either an organic material or an inorganic material can be used. Further, a fluorescent dye, a quantum dot material, or the like can be used as the infrared light emitting layer 15. In any case, the infrared light emitting layer 15 may be excited by the light emitted from the phosphorescent layer 13 and emit infrared light.

As described above, there are various materials applicable to the infrared light emitting layer 15, and among these, inorganic fluorescent pigments are particularly suitable in terms of weather resistance and light emission efficiency. As such inorganic fluorescent pigments, those containing trivalent neodymium (Nd ³⁺ ), trivalent ytterbium (Yb ³⁺ ), and trivalent erbium (Er ³⁺ ) are known. For example, Na ₅ (Yb, Nd) (MoO ₄ ) ₄ , (Y, La, Lu) PO ₄ : Yb, Nd, (Lu, Yb, Nd) ₂ O ₂ S, and the like.

  In addition to the screen printing, the phosphorescent layer 13 and the infrared light emitting layer 15 may be formed by offset printing, gravure printing, flexographic printing, pad printing, or the like, or may be formed by using a transfer sheet, a label, or the like. . Further, the above phosphorescent material or fluorescent material can be applied by spraying.

  FIG. 2 is a diagram schematically showing an example of the excitation spectrum and emission spectrum of the phosphor of the phosphor layer 13 and the phosphor of the infrared light emitting layer 15. FIG. 2A shows the phosphor, and FIG. 2B shows the phosphor. In each figure, the vertical axis is the spectrum intensity, the horizontal axis is the wavelength, the excitation spectrum that is the wavelength distribution of the excitation light is indicated by a solid line, and the emission spectrum that is the wavelength distribution of the emitted light is indicated by a dotted line.

  In the present embodiment, a phosphor that is excited by excitation light including a wavelength of 250 nm or more and 500 nm or less and emits visible light including a wavelength of 350 nm or more and 600 nm or less is used as the phosphor storage material of the light storage layer 13.

  Further, as the phosphor of the infrared light emitting layer 15, the light emitted from the phosphor layer 13 is excited by excitation light including a wavelength of 350 nm or more and 500 nm or less that overlaps with the wavelength of light emitted from the phosphorescent layer 13, and the emitted light becomes a wavelength range of 600 nm or more and 850 nm or less. Use what is included.

  However, the wavelengths of the excitation light and the emitted light of each layer are not limited to this, and the infrared light emitting layer 15 may be excited by the light emitted from the phosphorescent layer 13 to emit infrared light.

(2. Reading method of information recording medium 1)
Next, a method for reading the information recording medium 1 will be described with reference to FIG.

  In this embodiment, as shown in FIG. 3A, the information recording medium 1 is exposed in advance under a light source 20 such as sunlight or illumination light. The ultraviolet rays and visible light emitted from the light source 20 include the wavelength described above as the excitation light of the phosphorescent layer 13.

  This excitation light passes through a portion of the infrared light emitting layer 15 other than the phosphor and reaches the light storage layer 13, thereby exciting the light storage body of the light storage layer 13 and starting light emission. Then, the phosphor of the infrared light emitting layer 15 is excited by the light emitted from the phosphorescent layer 13, and the infrared light emitting layer 15 emits infrared light.

  Since the light emission state of the phosphorescent layer 13 is maintained for a certain time after excitation, the excitation / light emission state of the infrared light emitting layer 15 is also maintained accordingly. Therefore, when the information recording medium 1 is placed in a dark place 21 such as night, darkness, dark room where light does not reach as shown in FIG. 3B, even if there is no light source for exciting the infrared light emitting layer 15, Infrared light emitted from the infrared light emitting layer 15 can be received and read by the infrared reader 23. Further, the information recording medium 1 appears to shine by the light emission of the phosphorescent layer 13.

  In the present embodiment, a camera having sensitivity in the infrared region is used as the infrared reader 23, and infrared rays are received to perform shooting. If necessary, a filter may be attached to the infrared reader 23 to reliably cut the light from the phosphorescent layer 13. In the present embodiment, for example, a filter that cuts a wavelength of 700 nm or less may be attached. However, the infrared reader 23 is not limited to the configuration described above, and may be any device that can receive infrared rays. For example, a barcode reader may be used.

  An image photographed by the infrared reading device 23 is sent to the information processing device 24. The information processing device 24 acquires this image and performs display processing, authentication processing, and the like as necessary. The information processing apparatus 24 can be realized by a general computer including a control unit, a storage unit, a display unit, a communication unit, and the like.

  As described above, the image information recorded as the infrared light emitting layer 15 on the information recording medium 1 can be read in the dark place 21.

  As described above, in the information recording medium 1, the light storage body of the light storage layer 13 is excited by previously irradiating sunlight or illumination light as excitation light, and the light emission state is maintained even after excitation. In the information recording medium 1, the phosphor of the infrared light emitting layer 15 is excited by this light emission, and emits infrared light. Since the phosphorescent layer 13 maintains the light emitting state, the light emitting state of the infrared light emitting layer 15 is also maintained. Therefore, the image information formed by the infrared light emitting layer 15 can be read by infrared rays even in dark places 21 such as nighttime, darkness, and darkroom where light does not reach, which is highly convenient. Further, the information recording medium 1 has a simple configuration and does not require a dedicated light source for exciting the infrared light emitting layer 15 at the time of reading, so that the cost can be reduced.

  Furthermore, since the phosphorescent layer 13 emits visible light, it is possible to determine the authenticity of the information recording medium 1 by visually observing whether or not the phosphorescent layer 13 is shining in the dark place 21, and using infrared rays thereon There is an advantage that information can be read and authenticated. Moreover, since the reading by infrared rays can be performed by confirming the portion where the luminous layer 13 is shining, the operation is also easy.

  This information recording medium 1 can be used as, for example, various tickets, gold vouchers, lotteries, etc., and can be easily read in the dark place 21 to check tickets at night concerts, etc. Convenience increases in various situations such as when using.

  In addition, the infrared reader 23 may be arrange | positioned in the bottomed cylindrical housing | casing 25, as shown in FIG. In this case, when the information recording medium 1 is read, if the opening of the casing 25 is pressed against the surface of the information recording medium 1, the inside of the casing 25 becomes the same state as the dark place 21. However, reading can be performed in the same manner as described above.

[Second Embodiment]
FIG. 5A shows an information recording medium 1a according to the second embodiment. This information recording medium 1a is the same as in the first embodiment, but differs in that the infrared light emitting layer 15 is formed by a pattern having voids and image information is recorded.

  5B and 5C show the plane of the infrared light emitting layer 15 and a part of the plane enlarged. As shown in FIGS. 5B and 5C, in this embodiment, the infrared light emitting layer 15 is formed by repeating a pattern having dot-like or mesh-like voids 15a by printing. FIG. 5B shows an example in which a dot pattern is formed by offset printing or the like, and FIG. 5C shows an example in which a mesh pattern is formed by silk screen printing or the like. The space 15a is a portion where the infrared light emitting layer 15 is not formed in the pattern and the phosphorescent layer 13 is exposed upward. Therefore, when the image information itself is a shape having a hole, such as the characters “0” and “8”, it is different from the hole. In addition, the pattern which forms the infrared light emitting layer 15 is not restricted to a dot shape or a mesh shape, and it is only necessary to have a gap 15a.

  This information recording medium 1a can also read information by the same method as described above, and the same effect as in the first embodiment can be obtained. Further, since a gap is formed in the infrared light emitting layer 15, excitation light directly reaches the phosphorescent layer 13 exposed in the gap, so that it is possible to store a larger amount of energy and extend the emission time. There are effects such as an increase in emission intensity.

[Third Embodiment]
FIG. 6 is a diagram showing an information recording medium 1b according to the third embodiment. This information recording medium 1b uses the base material 11, the phosphorescent layer 13, and the infrared light emitting layer 15 similar to those of the first embodiment. However, the infrared light emitting layer 15 is formed on the base material 11, and the phosphorescent layer 13 is formed thereon. This is different from the first embodiment in that it is formed.

  Even in this case, the infrared light emitted from the infrared light emitting layer 15 excited by the light emitted from the light storing layer 13 passes through a portion other than the light storing material of the light storing layer 13 and is received by the infrared reader 23 to receive information. The recording medium 1b can be read. Therefore, the same effect as the first embodiment can be obtained. Furthermore, since the excitation light reaches the luminous layer 13 directly, the energy stored in the luminous layer 13 is also increased.

  On the other hand, the information recording medium 1 according to the first embodiment has an advantage that the infrared light emitted from the infrared light emitting layer 15 can be directly received by the infrared reader 23, and can be read with high accuracy.

  Next, an example in which the information recording medium 1 of the first embodiment is actually manufactured and read will be described as an example. However, the present invention is not limited to this.

<Formation of phosphorescent layer 13>
As a phosphorescent material for forming the phosphorescent layer 13, “N Luminous” (registered trademark) manufactured by Nemoto Lumimaterial Co., Ltd. was used as an ink by mixing the following materials. The blending weight ratio at this time is also shown below. In the following, “part” means part by weight.
Phosphor: N night light (Luminova) (Nemoto Lumi Material Co., Ltd.) 24 parts Resin: 800 medium (Seiko Advance Co., Ltd.) 100 parts Viscosity adjusting solvent: SS-E solvent 42 parts

  The phosphorescent material thus produced was solid-printed on the plain paper as the substrate 11 by silk screen printing using a 240 mesh silk screen printing plate to form the phosphorescent layer 13.

<Formation of infrared light emitting layer 15>
As a fluorescent material for forming the infrared light emitting layer 15, “VIR” manufactured by Nemoto Lumi Material Co., Ltd. was used as an ink by mixing the following materials. The blending weight ratio at this time is also shown below.
Phosphor: VIR (manufactured by Nemoto Lumi Material Co., Ltd.) ... 24 parts Resin: 800 medium (manufactured by Seiko Advance Co., Ltd.) ... 100 parts Viscosity adjusting solvent: SS-E solvent Slow exit (manufactured by DIC Corporation) ... 42 parts

  The fluorescent material thus produced was solid-printed on the phosphorescent layer 13 by silk screen printing using a 240 mesh silk screen printing plate to form the infrared light emitting layer 15. Thus, the information recording medium 1 was manufactured.

<Reading of information recording medium 1>
Next, the manufactured information recording medium 1 was read by the infrared reader 23. As the infrared reader 23, an infrared authentication sensor in which a high-pass filter for cutting light having a wavelength of 700 nm or less was installed on the light receiving side of the CCD camera.

  In reading, first, the information recording medium 1 was left under a fluorescent lamp for 3 minutes and then placed in a dark room where ultraviolet rays, visible light, and infrared rays were blocked. At this time, light emission of yellow-green visible light by the phosphorescent layer 13 was confirmed for the information recording medium 1.

  And when the part which emitted visible light was read by the infrared reader 23, the infrared light emission by the infrared light emitting layer 15 was confirmed. From the above, it was confirmed that the information recording medium 1 can be read by infrared rays.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

DESCRIPTION OF SYMBOLS 1, 1a, 1b ......... Information recording medium 11 ......... Base material 13 ......... Phosphorescent layer 15 ......... Infrared light emitting layer 21 ......... Dark place 23 ......... Infrared reader

Claims (6)

A phosphorescent layer that is excited by excitation light and maintains a light emitting state;
An infrared light emitting layer that emits infrared light when excited by light emitted from the luminous layer;
Is provided on a base material.   The information recording medium according to claim 1, wherein the phosphorescent layer is formed on the base material, and the infrared light emitting layer is formed on the phosphorescent layer.   The information recording medium according to claim 2, wherein the infrared light emitting layer is formed by a pattern having voids.   The information recording medium according to claim 1, wherein the infrared light emitting layer is formed on the base material, and the phosphorescent layer is formed on the infrared light emitting layer.   5. The information recording medium according to claim 1, wherein the luminous layer emits visible light. A method for reading an information recording medium, comprising: a phosphorescent layer excited by excitation light and maintaining a light emitting state; and an infrared emitting layer that emits infrared rays when excited by light emitted from the luminous layer;
A method for reading an information recording medium, wherein reading is performed by receiving infrared light emitted from the infrared light emitting layer excited by light emitted from the luminous layer.

Images