JPH09212576A - Bar code system using fluorescent material and reader for its bar code - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a bar code which is 'invisible' or 'unlike' a bar code without requiring any special higher cost by using a fluorescent material for the bar code. SOLUTION: The fluorescent material is used for the bar code 1, which is irradiated with specific exciting light emitted by the fluorescent material; and the luminescence of the fluorescent material is detected to read the bar code. There are, for example, thioflavin, fluoresin, eosin, rhodamine 6G, etc., as a ultraviolet-ray phosphor. The specific exciting light irradiating the fluorescent material is exciting light of wavelength making the phosphor luminesce and, preferably, light of infrared and ultraviolet wavelength ranges are used. Unrefined impressions on a conventional bar code can be removed and a digital bar code out of which whether or not fluorescent luminescence is present is read out is obtained to minimize read errors.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code system for reading the presence or absence of fluorescence emission of a phosphor substance, as opposed to a conventional bar code system for reading the intensity change of reflected light. More specifically, by using a fluorescent substance for a barcode, irradiating the barcode containing the fluorescent substance with specific excitation light, and detecting only the specific fluorescence emission emitted from the fluorescent substance The present invention relates to a bar code system and a bar code reader for reading the bar code. In addition, by using a colorless or white phosphor substance for the barcode under white light such as sunlight, a colorless or white single color "invisible" barcode can be obtained. Or, by using a monochromatic fluorescent substance mixed with a pigment for a bar code, the bar code system can be any color and monochromatic or multicolored and "barely aware" of the bar code and its bar code reading. It relates to the device.

[0002]

2. Description of the Related Art In the past, with the development of various automatic devices,
Systems have been developed and put into practical use that accurately and quickly read necessary information and perform various operations based on the information. As a medium for reading information, electromagnetic waves such as light and magnetism are often used. A well-known method using light is a method in which the surface of recorded information is irradiated with light and the reflected light is detected.

The bar code method has recently been used in a very wide range of applications as this reflected light detection system. The most everyday use is in retail stores,
It is a cashier machine such as a supermarket. Therefore, most of the products that are currently retailed have somewhere on the back, etc.
A bar code is printed that includes price and other information. Other uses of the bar code system include lending books at the library, managing mail, and booking programs for broadcast programs.

A bar code is a code that expresses information such as numbers, characters, and symbols by combining parallel vertical lines (bars) having different thicknesses and intervals, and each notation symbol is a code. The bar is called the element.
Among the parallel bars constituting the barcode, a bar having a low reflectance is called a black bar, and a bar having a high reflectance (interval portion) is called a white bar. The black bar is black in color to reduce the reflectance as much as possible in order to increase the contrast with the surrounding (white bar). Also, due to the performance of the reader,
It requires a certain size (area).

The above-mentioned white and black bar codes which can be discriminated by the human naked eye are read by an information reading device which is a bar code reader which irradiates light and detects reflected light with a sensor. A lamp, a light emitting diode, a gas laser, a semiconductor laser, or the like is used as the light source, and the sensor on the detector side detects the difference in the reflected light intensity between the white bar and the black bar of the bar code, and the decoder performs decoding processing. Do it.
Bar code readers include a method of tracing a code with a pen that you can see in retail stores, and a fixed method of irradiating a laser beam and automatically reading an object that flows at a high speed on a conveyor line. There are various forms. In addition, barcodes include JAN, ITF, Code 39, NW-
There are various types such as No. 7, code 128, etc., and they are used properly according to their characteristics. These are established and used as a consistent bar code system in each method from marking of bar code to reading of information.

[0006]

As described above, the bar code is black and needs to have a certain size (area). Therefore, the bar code is prominent. However, depending on the product, the presence of the barcode may break the image or atmosphere of the product. For example, when a large black bar code is printed or printed on the back cover of a high-priced art book, it may make people disillusioned. In other cases, it may be preferable not to be aware that the barcode is attached, that is, it may be preferable that the barcode is visually invisible or hard to see. There are also times when you want to be more proactive about using "invisible" barcodes. However, in the current situation, it is often the case that a black bar code is attached for the efficiency of business. In addition, products smaller than barcodes are sold in large bags with the barcode printed.

Further, in a bar code system utilizing visible light, if the surface on which information is recorded is dirty, damaged, folds, or if dew condensation or water drops adhere, the intensity of the reflected light becomes weak and the information is erroneous. There is a case where it is read. This is because the conventional method depends on the analog amount of the change in the intensity of the reflected light, and it is considered that the error can be reduced and the barcode itself can be made smaller by using a method of identifying some kind of digital amount. However, in spite of the problems and needs described above, a method of reading a barcode without relying on reflected light has not been devised so far.

[0008]

In view of the above situation, the present inventor uses a phosphor substance for a barcode instead of a conventional barcode system for reading the change in intensity of reflected light. In the case of detecting fluorescence emission from a body substance, it has been found that all of the above problems are solved and the present invention has been completed.

That is, the present invention uses a phosphor substance for a bar code, irradiates the bar code with a specific excitation light capable of emitting fluorescence from the phosphor substance, and detects fluorescence emission of the phosphor substance. The present invention provides a bar code system using a phosphor material, which is characterized by reading bar code information.

Further, the present invention provides a light source for generating light having an excitation wavelength of a phosphor substance used for a bar code, and an optical filter for selectively transmitting a part or all of fluorescence emitted from the phosphor substance. Another object of the present invention is to provide a bar code reading device using a phosphor substance, which comprises a photodetector and a photodetector.

[0011]

The present invention will be described in more detail below. In general, a phosphor substance is excited by an external stimulus such as infrared rays including near infrared rays, visible rays, ultraviolet rays, electromagnetic waves such as gamma rays, and particle rays such as alpha rays and beta rays. It returns to the ground state while emitting long-wavelength heat rays and visible rays. The phenomenon of light emission when this radiation is visible light is called fluorescence. Further, in the case of making a particular distinction, among fluorescences, those having a relatively long afterglow time are called phosphorescence, and further, phosphorescence.
The excitation wavelength and the fluorescence emission wavelength are values specific to the phosphor substance. In addition, Encyclopedia of Physics and Chemistry (Iwanami Shoten, 4th edition)
According to the above, the upper limit of the ultraviolet wavelength is 360 to 400 nm, the lower limit thereof is about 1 nm, and the upper limit of the visible light wavelength is 760 to 830.
nm, the lower limit is 360 to 400 nm, the upper limit of the infrared wavelength is about 1000 μm, and the lower limit is 0.76 to 0.83 μm (76
0-830 nm), and the upper limit of near infrared wavelength is about 2.5.
μm, the lower limit is about 0.76 to 0.83 μm.

Therefore, such a phosphor substance is used for a bar code, and the phosphor substance is irradiated with excitation light of a specific wavelength at which the phosphor substance emits fluorescence, so that the phosphor substance emits fluorescence. If detected, the barcode information can be read. Moreover, if only the fluorescence emission of the wavelength peculiar to the phosphor substance is detected, it can be captured as a digital signal by determining the presence or absence thereof,
It is possible to provide a method with less reading error as compared with the conventional method in which the intensity change is captured as an analog signal.

Further, since the present invention uses the fluorescent light emission when the fluorescent substance is irradiated with the excitation light, this information source relates to the color and the reflected light of the barcode itself under visible light. It is irrelevant because it is not affected by brightness. In other words, in a normal state where no special excitation light is applied, that is, under white light such as sunlight, it is not necessary to distinguish the conventional white bar from the black bar, and any color may be used. In particular, by using a colorless or white fluorescent substance barcode under sunlight, it is possible to form a monochrome or monochrome single-color barcode. It can be said that the barcode is "invisible" as a barcode according to the common sense of the conventional monochrome barcode. When the color of the phosphor material is a light color, it can be made “hard to see”. In addition, if it is not particularly harmful to the fluorescence emission, such a colorless, white or monochromatic phosphor substance may be mixed with pigments or dyes of various colors to add any monochromatic or polychromatic color. Colored barcodes can be formed, and barcodes can be made "oblivious". The arbitrary coloring may be a pattern, a design, a photograph or the like. For example, in the conventional bar code, if the fluorescent substance and any pigment are placed in the black bar portion and only the same pigment is placed in the white bar portion, the portion of the conventional black bar and the white bar is the sunlight in the present invention. You can finish the same color below. Of course, the phosphor substance and the coloring by the pigment or the like may be separately performed. The color of the phosphor material used in the present invention under sunlight does not necessarily have to be colorless, white or monochromatic, but as described above, when a white barcode is required or when arbitrary coloring is performed. Is a more preferable condition. As described above, the "invisible" barcode or the "unconscious" barcode is based on the above idea.

The structure of the fluorescent light information reading device in such a bar code system is configured to detect a light source suitable for the excitation wavelength of the phosphor used, an optical filter for selectively transmitting the fluorescence, and the transmitted light. It consists of a photodetector.

As the performance and physical properties required for the phosphor to be used, high luminous efficiency, strong absorption of excitation light, excellent durability such as weather resistance and light resistance, and sunlight It may be colorless, white or light colored under normal white light. In addition, the bar code is often recorded by means such as printing, but since a fluorescent bleaching agent or the like may be used on a printing medium such as a mount, the background and the bar code are temporally separated. For some purposes, afterglow phosphors may be preferred. As such a phosphor, for example, thioflavin, fluorescein, eosin, rhodamine 6G and the like are known as ultraviolet phosphors. These organic phosphors may be dispersed in an acrylic resin, a melamine resin or the like and used as a paint or ink. The processing method for utilizing the phosphor substance for the bar code may be a coating method, an ink, a resin kneading, or any other heat-resistant inorganic phosphor, such as thermal spraying, enamel, ceramics, etc., and various known methods. Can be considered.

In the present invention, the specific excitation light for irradiating the phosphor substance refers to excitation light having a wavelength capable of causing the phosphor to emit fluorescence, but preferably the infrared and ultraviolet wavelength ranges are used. More preferably, the infrared wavelength range is used. The reason for this is that in the case of ultraviolet rays, an ultraviolet lamp is usually used as the excitation light source, but it has a shorter life than solid-state elements such as light-emitting diodes, and ultraviolet rays are easily absorbed by dirt. Therefore, it is effective to combine a phosphor material having an excitation band in the infrared region, which is less likely to be absorbed by dirt, more preferably in the near infrared region, and a solid-state light source.

As a combination for this purpose, the following method can be considered, but it is not limited to this. That is, a method of using a green light emitting anti-Stokes phosphor containing Yb ³⁺ , Er ³⁺ having an excitation band in the near infrared region as a phosphor substance and a GaAs: Si infrared light emitting diode as a light source (emission wavelength: about 970 nm). Furthermore, as a phosphor substance, NdP ₅ O ₁₄ , Li (Nd _{1 -X} Y
b _X ) P ₄ O ₁₂ ,, (0 ≤ _X <1), Na ₅ Nd (W
O ₄ ) ₄ , Al ₃ Nd (BO ₃ ) ₄ and Cs ₂ NaN
There is a method using a so-called high-concentration type phosphor with little concentration quenching of dCl ₆ or the like, a GaAlAs infrared light emitting diode as a light source, and an InP polycrystalline filter and a Si phototransistor (light emission wavelength: about 800 nm) for detection. Further, as the infrared-visible conversion phosphor, an infrared stimulated phosphor obtained by adding a small amount of Sm (samarium), Eu (europium) or the like to CaS can be considered.

The phosphor used for the bar code in the present invention is difficult to identify with the naked eye unless it is irradiated with an excitation light beam for that purpose. When it is necessary to make a judgment, some kind of sensory marking is necessary. The marking method for this purpose allows a great variety of selections, and can be freely selected. For example, in the vicinity of the position where the barcode is recorded, a design, a trademark, or the like may be attached in various colors other than the color already used for the barcode, or a method of appealing to the sense of touch of a protrusion or the like may be used. When it is read by the detector, it can be automatically read and can be discriminated at night or in the dark regardless of the presence or absence of visible light. For example, there is a system that automatically reads the position of a stamp with a phosphor ink attached to a mail piece and surely stamps the stamp on the stamp.

There are various kinds of bar codes as described above, and they are used properly according to their characteristics. Since they are the most universally distributed, they are represented by bar codes, but for the same purpose. The code system used, eg
It goes without saying that the present invention can be similarly applied to a Carla code, a two-dimensional data code (box figure code) and the like.

Further, compared with the conventional system in which visible light or the like is irradiated and the reflected light is detected by a sensor to recognize information, the excitation light of a specific wavelength is used and the fluorescence emission due to this is detected by the sensor. Although the point that information is recognized is different, the other systems are the same, and the advantage is that the conventional method can be used as it is.

[0021]

As described above, the method of printing a barcode using a phosphor ink that is difficult to identify with the naked eye is as follows.
It seems that it can be applied to the forgery prevention of securities such as banknotes and checks, and it can also be applied to applications such as infrared sensor cards, and the practical value of the fluorescent bar code marking and reading system will be further expanded. The present invention provides a barcode which is "invisible" or "not aware" of the barcode without impairing the efficiency and advantages of the conventional barcode system and without requiring a particular increase in cost. In addition, it is possible to eliminate the unpretentious impression of conventional barcodes, and, in contrast to the conventional analog method that reads the intensity change of reflected light, a digital barcode that reads the presence or absence of fluorescence emission is used to reduce the reading error. It is extremely epoch-making and its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is an illustration of a bar code in the bar code system of the present invention.

FIG. 2 is an illustration of a bar code in a conventional bar code system.

FIG. 3 is an illustration of a barcode reading device in the barcode system of the present invention.

FIG. 4 is a description of a barcode reading device in a conventional barcode system.

[Explanation of symbols]

1: Bar Code Element Containing Phosphor Material 2: Bar Code Element Not Containing Phosphor Material 3: Conventional Black Bar Element 4: Conventional White Bar Element 5: Bar Code Adherent 6: Slit 7: Fluorescence Excitation light source for body substance 8: Light guide 9: Optical filter for selectively transmitting fluorescence from light-emitting substance 10: Photodetector for detecting the fluorescence 11: Data processing 12: Light source 13: Light receiving sensor 14: Data Indicates processing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C09K 11/85 CPF C09K 11/85 CPF G06K 19/06 G06K 19/00 AE

Claims (10)

[Claims] 1. A fluorescent substance is used for a barcode, and the barcode is irradiated with a specific excitation light capable of emitting fluorescence from the fluorescent substance, and the fluorescence emission of the fluorescent substance is detected to detect the barcode. A bar code system using a phosphor substance, which is characterized by reading information of. 2. The phosphor material used for barcode is
Thioflavin, fluorescein, eosin, rhodamine 6G, anti-Stokes phosphor, NdP ₅ O ₁₄ , Li (
Nd _1-X Yb _X ) P ₄ O ₁₂ , (0 ≤ _X <1), Na ₅ Nd
(WO ₄ ) ₄ , Al ₃ Nd (BO ₃ ) ₄ and Cs ₂ N
The bar code system using the phosphor material according to claim 1, wherein the bar code system is at least one or two or more phosphor materials of the group consisting of aNdCl ₆ . 3. A light source that emits light matching the excitation wavelength of a phosphor substance used for a bar code, an optical filter that selectively transmits a part or all of fluorescence emission from the phosphor substance, and light detection. A bar code reader using a phosphor material consisting of a container and a container. 4. The bar code reading device according to claim 3, wherein the wavelength of the specific excitation light capable of emitting fluorescence from the phosphor substance is a wavelength in the infrared or ultraviolet wavelength range. 5. The bar code reading device according to claim 3, wherein the wavelength of the specific excitation light capable of causing the fluorescent substance to emit fluorescence is a wavelength in the near infrared region. 6. The phosphor material used for a barcode is
4. The barcode reading device according to claim 3, wherein a fluorescent substance that is colorless or white under sunlight is used. 7. The phosphor material used for barcode is
4. The bar code reader according to claim 3, wherein the bar code reader is colorless, white or light-colored under sunlight, and a pigment is added to the phosphor substance. 8. The phosphor material used for barcode is
Thioflavin, fluorescein, eosin, rhodamine 6G, anti-Stokes phosphor, NdP ₅ O ₁₄ , Li (
Nd _1-X Yb _X ) P ₄ O ₁₂ , (0 ≤ _X <1), Na ₅ Nd
(WO ₄ ) ₄ , Al ₃ Nd (BO ₃ ) ₄ and Cs ₂ N
Bar code reading apparatus according to claim 3, wherein where at least one or more of the phosphor material of the group consisting of aNdCl _6. 9. An anti-Stokes phosphor as a phosphor substance used for a barcode, and GaAs: Si as a light source.
4. The bar code reading device according to claim 3, wherein the infrared light emitting diode is used. 10. A high-concentration phosphor as a phosphor substance used for a bar code, a GaAlAs infrared light emitting diode as a light source, an InP polycrystalline filter as an optical filter, and a Si phototransistor as a detector. The bar code reading device according to claim 3.