JP3860595B2 - Optical reader - Google Patents

Description

  The present invention relates to an optical reader capable of optically reading a latent image printed with a phosphor composition.

(Prior art 1)
In recent years, bar code has been actively managed in various industries, mainly in the distribution industry, and bar codes have been printed on various prepaid cards or pass-through cards. The barcode is used to read a predetermined processing operation.

  A system for processing articles by forming latent images (for example, barcodes) for identification with phosphors emitting fluorescence in the infrared region on the surfaces of various articles and reading them with an optical reader. Yes. Compared to the conventional system that uses a visible ink such as black to form a mark on the surface of an article and reads the mark using a change in reflectance of visible light, the system using this latent image is, for example, the following. It has the following features.

(A) Depending on the color of the article, there are few errors in reading the latent image, and the reliability is high.

(B) Even if the latent image forming surface is dirty, since the emitted infrared light has a long wavelength, there is little error in reading, and the reliability is high.

(C) Since the phosphor is visually nearly colorless, the appearance is not impaired even if it is printed on the surface of the product.

(D) Since it is a latent image, it is difficult for others to recognize it, which helps to keep information secret.

  Conventionally, as this type of related technology, there are inventions described in, for example, Japanese Patent Publication No. 55-33837, Japanese Patent Publication No. 60-29996 and Japanese Patent Publication No. 62-24024.

(Prior art 2)
Conventionally, inorganic phosphors containing neodymium (Nb), ytterbium (Yb), and erbium (Er) are known as infrared phosphor inks used for data cards (for example, the United States). (See patent specification 4,202,491).

  Among these, the inorganic phosphor using Nb alone as an optically active element has a fluorescence maximum intensity wavelength of around 1050 nm when a GaAlAs light emitting diode having an excitation wavelength of 800 nm is used, and Nb and Yb as optically active elements. Inorganic phosphors containing these two types have a maximum fluorescence wavelength of around 980 nm when a GaAlAs light emitting diode with an excitation wavelength of 800 nm is used, and inorganic fluorescence containing two types of Yb and Er as optically active elements When a GaAs light emitting diode with an excitation wavelength of 940 nm is used, the maximum fluorescence wavelength is around 1540 nm, and an inorganic phosphor containing three kinds of Nd, Yb and Er as optically active elements has an excitation wavelength of It is known that when an 800 nm GaAlAs light emitting diode is used, the maximum fluorescence wavelength is around 1540 nm. .

(Prior art 3)
For example, as shown in Japanese Patent Publication No. 56-4598, Nd having a large absorption characteristic with respect to light in the infrared region is used as an optically active element, and excitation energy is transferred from the optically active element to the emission center. Materials with high emphasis on emission intensity, such as alkali metal salts (for example, Na ₂ MoO ₄ ), which are highly efficient base materials, and Yb, which is a luminescent center with good wavelength matching with Si photodetectors, are selected. It was.

(Prior art 4)
Conventionally, a mark (latent image) is formed using a phosphor that emits light in the infrared wavelength region, and an optical filter that utilizes the fact that the emission center wavelength of the excitation light irradiated to this mark and the fluorescence emitted from the phosphor is different. There is known a method of determining the presence or absence of a mark by separating only fluorescence from reflected light (excitation light) by using (see, for example, Japanese Patent Publication Nos. 54-22326 and 61-18231).

  In addition, the applicant previously irradiates the mark formed with the phosphor intermittently with excitation light and detects the presence or absence of afterglow generated from the mark during the irradiation stop period. A detection method and apparatus have been proposed (see, for example, Japanese Patent Laid-Open Nos. 3-16369 and 5-20512).

(Prior art 5)
FIG. 70 is a diagram showing a schematic configuration of a conventional optical reading apparatus. As shown in the figure, the latent image barcode 401 is excited by irradiating light of a specific wavelength, for example, infrared rays 402, and phosphor fine particles that emit fluorescence 403 having a wavelength different from the infrared rays 402 are contained in the binder. It is formed on the workpiece 404 by printing with the dispersed and retained ink.

  An apparatus for reading information from the latent image barcode 401 receives a light emitting unit 405 that irradiates the infrared ray 402, a fluorescent light 403 from the latent image barcode 401, and reflected light 406 from the work 404, and outputs an electric signal. A light receiving unit 407 for conversion, an amplifier 408 for amplifying an electrical signal, and information recorded by the latent image barcode 401 from an output signal of the amplifier 408 (hereinafter, this signal is referred to as an “analog reproduction signal”). And a signal detection unit 409 for detection.

  The signal detection unit 409 includes an A / D converter, and the analog reproduction signal is binarized by the A / D converter to reproduce the information recorded in the latent image barcode 401.

  In general, a comparator is used to binarize the analog reproduction signal, and an analog reproduction signal a and a slice signal b having a certain level as shown in FIG. A binary signal is obtained by slicing with the slice signal b.

The following patent documents can be cited as known techniques relating to this type.
Japanese Patent Publication No.54-22326 Japanese Patent Publication No. 61-18231 Japanese Unexamined Patent Publication No. 03-16369 Japanese Patent Laid-Open No. 05-20512

(Technical issue 1)
Any of the mark detection methods described in Japanese Patent Publication No. 54-22326, Japanese Patent Publication No. 61-18231, Japanese Patent Application Laid-Open No. 3-16369, and Japanese Patent Application Laid-Open No. 5-20512 can be used. The mark formation position is determined by detecting the fluorescence generated from the mark by irradiation with a detector. However, since the amount of light incident on this detector fluctuates violently in response to changes in its detection environment and conditions, complicated circuit processing is required to maintain high detection accuracy at the mark position. There were inconveniences such as limited use conditions.

  As a result of investigations in view of such inconveniences, the present inventors have grasped changes in detection conditions accurately because any of the methods for detecting fluorescence described above has little information obtained from other than the data portion. Is difficult.

(Technical issue 2)
In the conventional method of separating the reflected light of the excitation light and the fluorescence using the optical filter, the emission center wavelength of both lights is close and the intensity of the fluorescence is extremely weak compared to the intensity of the reflected light. It is technically difficult to accurately separate both lights, and a large amount of reflected light component remains, resulting in a decrease in detection accuracy.

  On the other hand, in the method using the afterglow described above, the presence or absence of reflected light is not a problem and only fluorescence can be effectively separated and detected, but when dust adheres to the light receiving surface of the detector, the detection sensitivity decreases, The absolute value of the afterglow generated from the mark also decreases, and the afterglow detection accuracy decreases.

(Technical issue 3)
In the latent image detection method described in Japanese Patent Laid-Open No. 3-16369 and Japanese Patent Laid-Open No. 5-20512, if there is external light having a wavelength that is the same as or close to the wavelength of fluorescence, the light is received as it is. And is converted into an electrical signal, there is a possibility that it may be mistaken for fluorescence even though fluorescence is not generated.

  Therefore, in order to prevent such misidentification, there is a disadvantage that the use environment is limited, for example, it is required to use the light irradiation and detection position while shielding the external light.

(Technical issue 4)
The level and amplitude of the analog reproduction signal of the optical reader shown in FIG. 71 are greatly affected by the physical properties of the ground on which the latent image barcode is formed. That is, when the background is made of a material that easily absorbs transparent ink and easily absorbs the excitation light emitted from the light projecting unit, the amount of light emitted from the latent image barcode and the amount of reflected light from the background are reduced. Therefore, as shown in FIG. 71 (b), the level of the analog reproduction signal is low and the signal amplitude is small.

  When the base is made of a material that easily absorbs transparent ink and reflects light emitted from the light projecting unit, the analog reproduction signal is offset to the high level side as shown in FIG. 71 (c). . Further, when the base is made of a material that hardly absorbs transparent ink and easily absorbs light emitted from the light projecting unit, the analog reproduction signal has a large signal amplitude as shown in FIG. Become.

  Therefore, in the conventional reading apparatus in which no consideration is given to the fluctuation of the waveform of the analog reproduction signal due to the difference in the background on which the latent image barcode is formed, for example, the latent image barcode is applied to various workpieces having different background materials. The latent image bar code is formed and read by one reading device, or when one workpiece is made of various materials and the latent image barcode formed over each part is read by the reading device. Is likely to cause inconvenience that it cannot be read accurately. In addition, such an inconvenience can be avoided if an optical filter (single wavelength filter) that transmits only the fluorescence from the latent image barcode and cuts all the reflected light from the base is provided on the front surface of the light receiving unit. However, the single wavelength filter is expensive and cannot be mounted on an actual machine from the viewpoint of cost. Usually, a band-pass filter that cuts a part of the reflected light is installed, so that the inconvenience described above is obtained. It becomes a problem.

  An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a highly reliable optical reading apparatus.

In order to achieve the above object, the first invention provides
In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to irradiated excitation light, detecting fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Photoelectric conversion means for taking in light emitted from the irradiation position of the excitation light and converting it into an electrical signal;
Waveform detection means synchronized with the irradiation timing of the light irradiation means, the minimum value corresponding immediately before the irradiation start, the maximum value corresponding immediately before the irradiation stop, and the detection value immediately after the irradiation stop,
Comparing a comparison value obtained by dividing the difference between the maximum value and the minimum value with the detection value, and a mark determination means for determining a mark formation position when the detection value exceeds the comparison value. It is.

In order to achieve the above object, the second invention provides
In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to irradiated excitation light, detecting fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Photoelectric conversion means for inputting light emitted from the irradiation position of the excitation light and converting it into an electrical signal;
Waveform shaping means that inverts and amplifies half of the output signal from the photoelectric conversion means while synchronizing with a timing that is 90 degrees out of phase with the irradiation period of the light irradiation means;
And low-pass filtering means for selectively extracting a direct current component from the output signal from the waveform shaping means.

In order to achieve the above object, the third aspect of the present invention provides
In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to irradiated excitation light, detecting fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Filtering means for selectively capturing light of a wavelength component of fluorescence from light emitted from the irradiation position of the excitation light;
Photoelectric conversion means for converting light taken in through the filtering means into an electrical signal;
Waveform shaping means that inverts and amplifies half of the output signal from the photoelectric conversion means while synchronizing with a timing that is 90 degrees out of phase with the irradiation period of the light irradiation means;
Low-pass filtering means for selectively extracting a DC component from the output signal by the waveform shaping means,
Comparing means for comparing the detection voltage output from the low-pass filtering means with a set voltage and outputting a predetermined detection signal when the detected voltage exceeds the set voltage is provided.

The first aspect of the present invention relates to
When light is irradiated to the mark from the light irradiation means, fluorescence of a predetermined wavelength is generated in addition to the reflected light from the light irradiation position on the mark. The incident light including the reflected light and the fluorescence is selectively captured by the optical filtering means and then converted into an electrical signal by the photoelectric conversion means, and further processed by the waveform detection means. Done.

  The waveform detection means individually detects the magnitude of the incident light amplitude and the fluorescence intensity. Therefore, a comparison value that changes according to the intensity of the incident light is created, and the comparison value and the detection value are compared in the next mark determination means, so that the comparison value corresponds to the intensity change of the incident light itself. Is automatically set to the optimum value.

  Furthermore, the magnitude of incident light is always determined by the signal input determining means, and only when the significant incident light is detected, the determination operation by the mark determining means is started, so that only genuine data is compared with the detected value. Since it is used as a value, the reliability can be improved.

The second and third aspects of the present invention include
When the mark is irradiated with intermittent light from the light irradiation means at a predetermined timing, the light is incident on the optical filtering means from the light irradiation position. Among the light, the wavelength distribution is random, but the intensity of the reflected light is different from the external light whose intensity is substantially constant, the reflected light whose wavelength distribution is specified but the intensity changes in a rectangular wave shape, and the like. The fluorescence includes a specific wavelength, but the intensity changes while increasing / decreasing with light irradiation.

  Therefore, optical filtering means that selectively allows light of the fluorescence wavelength to pass through is used to attenuate light components other than fluorescence from incident light as much as possible. Then, the photoelectric conversion means converts the light intensity of the electrical signal. Convert to strength.

  Here, the intensity of the external light is substantially constant, and the intensity of the reflected light itself is constant but intermittently. On the other hand, the fluorescence component changes while increasing or decreasing its intensity at the same timing as the reflected light according to the irradiation light, as exemplified by the solid line in FIG. That is, the intensity of fluorescence is the strongest before and after the time when the irradiation light is turned off, and both the light emission and afterglow are the strongest, and the intensity before and after the turn-on time is the weakest.

  Therefore, in the waveform shaping means, the input signal in that period is inverted and amplified at a timing 90 degrees out of phase with the light irradiation period while taking the light irradiation timing of the irradiation light, as shown in FIG. 56 (f). In addition, for example, a strong half cycle for both emission and afterglow is extracted as a change in positive voltage, and a weak half cycle is extracted as a change in negative voltage.

  By the way, while the components of the external light and the reflected light are equal in both positive and negative, the signal of the fluorescence is inverted so that the difference between the two becomes the largest. Accordingly, both the external light and the reflected light are canceled by passing through the next low-pass filtering means, but if a fluorescent component is included, the difference between the positive and negative signals is taken out as a DC voltage. Therefore, this voltage is compared with the set value by the comparison means, and if it is determined that it is a significant value, a mark signal indicating the mark position is output.

Next, each embodiment of the present invention will be described separately according to the following items.
A. Phosphor and phosphor composition.
B. Method for printing phosphor composition and latent image forming member.
C. Optical reader and optical reading system.

1. [Phosphor and phosphor composition]
Phosphor composition example 1
An organometallic compound containing at least neodymium (Nd) as an optically active element, preferably an organometallic compound containing neodymium (Nd) and ytterbium (Yb).

  The organic substance in the organometallic compound is at least one organic substance selected from the group of carboxylic acids, ketones, ethers, and amines.

  More specifically, the organometallic compound is at least selected from the group consisting of neodymium cinnamate, neodymium cinnamate / ytterbium composite salt, neodymium ytterbium benzoate, neodymium naphthoate, neodymium naphthoate / ytterbium composite salt. One kind of organometallic compound. Of these, carboxylic acid complex salts composed of cinnamic acid and Nd and Yb are preferred.

  The content mole fraction of Nd and Yb is appropriately selected within the range of Nd: Yb = 9.5: 5 to 3: 7 from the results shown in FIG. 2, which will be described later, and particularly from the point of emission intensity, 9: 1 to 5: 5. The range of is preferable.

  This phosphor may be synthesized by any method. D. Ion exchange reaction in aqueous solution reported by Taylor et al. [J. Inorg. Nucl. Chem. , 30, 1503-1511 (1968)], or P.I. N. Isopropoxide release reaction in nonpolar solvents reported by Kapoor et al. [Synth. React. Inorg. Met. -Org. Chem. , Vol. 17, 507-523 (1987)].

  Unlike inorganic phosphors, this phosphor has organic substances such as carboxylic acid, β-diketone, cyclic ether, and cyclic amine in the molecule. In particular, cinnamic acid, a kind of carboxylic acid, is chemically stable. In addition, the light emission output is larger than the others, which is preferable.

  The average primary particle size of the phosphor is conveniently about 80% or less of the maximum intensity wavelength of infrared light (810 nm) as excitation light, and about 70% of the maximum intensity wavelength of light emitted from the phosphor (980 nm). It is as follows. This phosphor does not form solid primary particles like inorganic phosphors, and does not damage the phosphor crystals, so it is easy to grind and finer when dispersed with a binder. Become. When ink for an ink jet printer is made, the ink is not stably dispersed and settled in the binder, and the nozzle clogging and the ejectability of droplets are not deteriorated.

  A specific example of manufacturing the phosphor is as follows.

  Cinnamic acid 1.24 g (8.37 mol) and sodium hydroxide 0.37 g (8.37 mol) were each added to 120 ml of ion-exchanged water with stirring to obtain an aqueous sodium cinnamate solution. Adjust to pH 10 with aqueous sodium acid solution.

  Separately, 0.50 g (1.39 mol) of neodymium chloride hexahydrate and 0.54 g (1.39 mol) of ytterbium chloride hexahydrate are completely dissolved in 50 ml of ion-exchanged water. When this aqueous solution is added to the aqueous sodium cinnamate solution with stirring at room temperature, a precipitated product is obtained.

  Thereafter, the reaction solution was adjusted to pH 5 with 0.1N hydrochloric acid, stirred for 2 hours, and the resulting precipitated product was filtered, washed and dried at 120 ° C. for 5 hours, and neodymium cinnamate ytterbium cinnamate. A (1/1) complex salt is obtained. The yield was 1.62 g (yield: 93.1%).

  FIG. 1 is an emission spectrum diagram of neodymium cinnamate / ytterbium (1/1) composite salt using a GaAlAs light emitting diode as an excitation source, and shows a maximum peak at around 980 nm.

  FIG. 2 is a characteristic diagram showing the relationship between the molar ratio of Nd / Yb and the emission intensity. As shown in FIG. 2, the molar ratio of Nd / Yb is 9.5 / 5 to 3/7, preferably 9/1. It has a high light output at 5/5.

  The average particle size of neodymium cinnamate / ytterbium composite salt is 0.2 μm, about 25% of the maximum intensity wavelength of excitation light (0.81 μm), and about 20% of the maximum intensity wavelength of fluorescence emitted (0.98 μm). It is much smaller than the highest intensity wavelength of excitation light and the highest intensity wavelength of fluorescence.

  A benzone neodymium ytterbium (1/1) composite salt can be prepared in the same manner except that cinnamic acid is changed to benzoic acid in the above production example, and the average particle size of this phosphor is the maximum intensity wavelength of excitation light and It is smaller than the maximum intensity wavelength of the emitted fluorescence.

  In addition, ultrafine phosphors made of organometallic compounds such as neodymium cinnamate, neodymium naphthoate, neodymium naphthoate / yttebium complex, and neodymium benzoate can also be used.

  Since the maximum intensity wavelength of excitation light and the maximum intensity wavelength of fluorescence of these phosphors exceed approximately 0.8 μm (800 nm), when a phosphor having an average particle size of 0.8 μm or less is used, the excitation light enters. As well as the emission of fluorescence.

  FIG. 3 is a characteristic diagram showing an irradiation state of excitation light and a light emission state of a phosphor. (A) in the figure shows the irradiation state of the GaAlAs light emitting diode, and the excitation light is irradiated intermittently at intervals of 2000 μsec.

FIG. 2B shows the light emission state of the neodymium cinnamate / ytterbium (1/1) composite salt obtained in the above-mentioned production example. The rise time t _u until reaching% is about 100 μsec. The fall time t _d until the emission intensity of the afterglow is attenuated by 80% from the maximum emission intensity after the irradiation of the excitation light is stopped is about 50 μsec. As a result, the rise time t _u and the fall time t _d are Both are very excellent in response within 200 μsec.

FIG. 5B shows the light emission state when the phosphor is LiNd _0.5 Yb _0.5 P ₄ O ₁₂ , the rise time t _u is about 1300 μsec, the fall time t _d is about 1000 μsec, and the rise time t _u. In addition, both the fall times t _d greatly exceed 200 μsec.

As described above, when the phosphor rise time t _u is within 200 μsec, the time from when the excitation light is applied until the light receiving element receives the fluorescence is very short, so that the latent image can be read by the phosphor at high speed. .

  As shown in FIG. 4, when the code information is read by the optical reading device 25 while conveying the latent image forming member 10 in which the printing layer 18 such as a barcode is formed using a phosphor, the code information in the optical reading device 25 is read. The phosphor in the printing layer 18 is activated by the excitation light 60 emitted from the light emitting element, and the fluorescence 61 emitted from the printing layer 18 is received by the light receiving element in the optical reader 25 to read the code information. Can do.

  A slit member 32 is provided on the optical path for irradiating only the predetermined print layer 18 with excitation light 60 and receiving only the fluorescent light 61 therefrom, as will be described in detail later.

When the conveying speed v of the latent image forming member 10 at this time, d the length of the conveying direction of the slit 32a in the slit member 32, the rise time of the phosphor was set to _{t u, t u ≦ d /} v
If the relationship is established, the information of the printing layer 18 being conveyed can be reliably read while facing the slit 32a.

If the rise time t _u of the phosphor is longer than d / v, the printed layer 18 passes under the slit 32a without having sufficient light emission intensity, and therefore the output of the light receiving element is weak. There is a problem with reliability. That respect, the use of a phosphor having a rise time t _u such as the above equation is satisfied, the reading of the information is reliable. As described above, by using a phosphor having a short rise time _tu , it is possible to increase the conveyance speed v of the latent image forming member 10 and increase the reading speed.

Further, as shown in the figure, when the interval between the print layers 18 (for example, bars) in the transport direction of the latent image forming member 10 is L, and the falling time of the phosphor is t _d ,
t _d ≦ L / v
If the relationship is established, the code information can be read properly. If a phosphor having a relatively long fall time t _d , in other words, a phosphor having a relatively long afterglow time is used, the afterglow from the previous printing layer 18 that has been transported and passed is also read. Therefore, the code information cannot be read properly.

When the fall time t _d of the phosphor is contrary to use very short phosphor as in FIG. 3 (b), rather than adverse effects as described above, it is possible to properly read the code information, moreover the bar It is also possible to narrow the latent image forming area by shortening the interval L.

    By using an organic binder having a density (ρ2) that satisfies the relationship of ρ1 / ρ2 ≦ 1.8 with respect to the density (ρ1) of this phosphor, there is less sedimentation of phosphor fine particles in the ink, Even when the printing layer is formed, the problem that the phosphor fine particles are hidden deep in the coating of the binder and the excitation light does not easily reach can be eliminated.

    The binder content in the printed layer needs to be 5% by weight or more. If it is less than that, the phosphor particles may fall off, so that printing of barcodes and the like becomes incomplete, and proper information cannot be retained. Therefore, the binder content needs to be 5% by weight or more.

    As the water-soluble organic binder, for example, an acrylic resin and an acrylic resin containing an ester group or a polyether in the side chain are used. In addition, polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, starch, formalin condensate of naphthalene sulfonate, polystyrene sulfonate, and the like can also be used.

    Examples of water-insoluble organic binders include phenolic resins such as novolak-type phenol, resole-type phenol, rosin-modified phenol, and alkyl-modified phenol, hydrogenated rosin, and polyethylene glycol esters, polyhydric alcohol esters, and rosin glycerin esters thereof. There is rosin resin.

    As the solvent, water, alcohol, ketone, ester, ether, aromatic hydrocarbon solvent, aliphatic hydrocarbon solvent or the like may be used alone or in combination.

Further, LiNO ₃ , LiCl, KCl, NaCl, KNO ₃ or the like is used for the electrolyte as the conductivity imparting agent.

    As the stabilizer, alkyl phthalate (eg, dioctyl phthalate, dibutyl phthalate, etc.), allyl phthalate, glycol (ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, etc.), glycol ester, etc. are used alone or in combination.

    As the antifoaming agent, silicon-based, silica-silicon-based, metal soap, amide-based, polyether-based and the like are used.

    A dye can also be used in combination. Examples of the dye include direct black GW, capamin black ESA, rhodamine B, rhodamine 7G, methylene blue, direct first orange, conplantin green G, milling yellow O, and cationic pink FG.

An example of a specific composition of ink for an ink jet printer is as follows.

Neodymium cinnamate / ytterbium complex salt (average particle size 0.2 μm)
80 parts by weight Phthalocyanine blue 1 part by weight Cationic acrylic resin 20 parts by weight Polyethylene glycol 1 part by weight Dioctyl phthalate 0.5 part by weight KCl 0.5 part by weight Antifoaming agent 0.4 part by weight Water 100 parts by weight Ethanol 20 parts by weight

This composition was mixed and dispersed in a sand mill for 1 hour to prepare an ink for an ink jet printer, and this was used to print on paper with an ink jet printer. When the state of printing was observed, no ink oozing was observed, and it was a highly accurate blue printing.

  In order to optically detect this print, the light having the highest intensity wavelength is excited by irradiating it with a wavelength of around 970 nm, the fluorescence is received by the silicon photodiode detector, and the reading test is performed 100 times at a reading speed of 4 m / sec. As a result, it was possible to reliably detect the print information 100 times.

  In the ink composition, the addition amount of phthalocyanine blue, polyethylene glycol, dioctyl phthalate, water, ethanol, etc. can be increased or decreased as necessary.

  As described in the above composition table, when water is used as the solvent, when using water and a readily volatile organic liquid compatible with the water, such as alcohol, the phosphor composition is quickly dried. When printing a phosphor composition on paper or the like, it is also effective particularly when the amount of solvent is large as in ink jet printing.

  In the ink composition, various kinds of inks having different viscosities were prepared by changing the addition amount of the cationic acrylic resin, and the viscosity of the ink, the rate of change in the size of the droplets, and the relativeity of the printed fluorescent layer were adjusted. The relationship with the light emission output was examined, and the result is shown in FIG.

  As is apparent from this figure, when the viscosity of the ink for an ink jet printer is in the range of 2 to 25 cps, preferably 10 to 20 cps, uniform droplets can be obtained with a rate of change in droplet size of 10% or less. The printability is excellent, and sufficient light output is obtained. In addition, when the viscosity of the ink for inkjet printers exceeds 25 cps, clogging of print nozzles or the like occurs, and printing becomes difficult.

  In the ink composition, various types of inks with different surface tensions were prepared by varying the amount of ethanol added, and the relationship between the surface tension of the ink and the rate of change in droplet size was examined, and the results were shown in FIG. This is shown in FIG.

  As is apparent from this figure, when the surface tension of the ink for an ink jet printer is in the range of 23 to 40 dyne / cm, preferably 26 to 37 dyne / cm, the change rate of the droplet size is small, which is necessary for the ink jet printer. Uniform droplets are obtained and the printability is excellent.

  In the ink composition, various kinds of inks having different specific resistances were prepared by variously changing the addition amount of the electrolyte (KCl), and the relationship between the specific resistance of the ink and the rate of change of the droplet size was examined. The results are shown in FIG.

  As is clear from this figure, when the specific resistance of the ink for an ink jet printer is in the range of 2000 Ωcm or less, preferably 1500 Ωcm or less, the change rate of the droplet size is small, and the uniform droplets necessary for the ink jet printer are formed. Obtained and excellent in printability. If the specific resistance of the ink for an ink jet printer exceeds 2000 Ωcm, particularly in the case of the charge deflection printing method, it becomes difficult to control the deflection of the droplets, and the printing is lost or bent, resulting in a reduction in printing quality.

  In the ink composition, KOH was added in addition to KCl, and various addition amounts were adjusted to adjust various types of inks having different pH values, and the relationship between the pH of the ink and the dispersion stability was examined. Is shown in FIG. The dispersion stability was expressed as a percentage of the total amount of supernatant after the obtained ink for inkjet printers was left for one week.

  As is apparent from this figure, when the pH of the ink for an ink jet printer is in the range of 4.5 to 10, preferably 5 to 7, the dispersibility of the ink and the subsequent stability are very good. When the pH of the ink for an ink jet printer is less than 4.5 or exceeds 10, the pigments in the ink tend to aggregate.

  Thus, the ink for an inkjet printer of the present invention has a dispersion stability by regulating the viscosity to 2 to 25 cps, the surface tension to 23 to 40 dyne / cm, the specific resistance to 2000 Ωcm or less, and the pH to 4.5 to 10. Good, no bleeding at the time of printing, excellent printability, and large light emission output can be obtained.

Phosphor composition example 2
A phosphor composed of an oxygenate compound containing one or more elements of Nd, Yb, and Er. Specific examples of the oxygenate compound include vanadate compounds, phosphate compounds, borate compounds, molybdate compounds, and tungstate compounds. Can be used for awards due to its excellent chemical resistance.

  More specifically, there is an infrared light emitting phosphor made of a phosphate having the following general formulas (1) and (2).

General formula (1)
Ln _X A _1-X PO ₄
Wherein Ln is at least one element selected from the group of Nd, Yb, Er,
A is at least one element selected from the group of Y, La, Gd, Bi, Ce, Lu, In, and Tb;
X is a numerical value in the range of 0.01 to 0.99.

General formula (2)
DE _1-X Ln _X P _Y O _Z
Wherein D is at least one element selected from the group of Li, Na, K, Rb, Cs,
E is at least one element selected from the group consisting of Y, La, Gd, Bi, Ce, Lu, In, and Tb;
Ln is at least one element selected from the group of Nd, Yb, Er,
X is a numerical value in the range of 0.01 to 0.99,
Y is a numerical value in the range of 1-5,
Z is a numerical value in the range of 4-14.

  In addition, D of General formula (2) is not necessarily required. Further, the values of X, Y, and Z in the general formula (2) are not clearly grasped at present, and are presumed to be in the above-mentioned range.

  FIG. 9 to FIG. 9 show the proportions of raw materials and the firing time in specific production examples (samples 1 to 14) and comparative examples (sample 15) of these phosphors, and the composition and particle size of infrared phosphors produced thereby. As shown in FIG.

  The raw materials shown in FIGS. 9 and 10 were fired at each temperature for 2 hours, and then treated with hot water and 1 mol of nitric acid to remove unreacted substances, thereby obtaining an infrared-emitting phosphor.

  As is apparent from FIGS. 11 and 12, the phosphor particles obtained in the examples of the present invention are smaller than the comparative example (6 μm) and are 4 μm or less, and some of them are very small particles of 1 μm or less. Some are smaller than the maximum intensity wavelength of the excitation light and / or the maximum intensity wavelength of the emitted fluorescence, as described above.

  Further, when the phosphor particles are observed with a scanning electron microscope, the shape and size of the particles are uniform, and the shape of the particles is not a needle shape but a shape like a stone in a river.

  The emission spectra of Sample 1 and Sample 7 according to the example of the present invention and Sample 15 as a comparative example are shown in FIG. 13, FIG. 14, and FIG. 15, respectively. In the case of the sample 1 shown in FIG. 13, the excitation wavelength is 0.81 μm (810 nm) and the fluorescence wavelength is 0.98 μm (980 nm), whereas the average particle size is 0.6 μm. These are extremely small particles smaller than the wavelength. In the case of the sample 7 shown in FIG. 14, the fluorescence wavelength is 1.59 μm, whereas the average particle size is 1.0 μm.

  Since other binders, solvents, and the like constituting the phosphor composition are the same as those described in the phosphor composition 1, description thereof is omitted.

Phosphor composition 3
Use phosphors containing Fe and Er as optically active elements, and containing at least one element selected from the group of Sc, Ga, Al, In, Y, Bi, Ce, Gd, Lu, and La To do.

  More specifically, an infrared light emitting phosphor having the following general formulas (3) to (5) is used.

General formula (3) G ₃ J ₅ O ₁₂
General formula (4) GJO ₃
General formula (5) G ₂ J ₄ O ₁₂
Where G is composed of Er and at least one element selected from the group of Y, Bi, Ce, Gd, Lu, and La;
J is composed of at least one element selected from the group of Sc, Ga, Al, and In and Fe.

The phosphors having the general formulas (3) to (5) are used alone or in the form of a mixture.

  More specifically, the following infrared light emitting phosphors are used.

(A) Er _0.2 Y _2.8 Fe _1.5 Al _3.5 O ₁₂
(B) Er _0.5 Y _2.5 Fe _1.5 Ga _3.5 O ₁₂
(C) Er _0.2 Lu _2.8 Fe _2.5 Al _3.5 O ₁₂
(D) Er _0.05 La _0.95 Fe _0.3 Al _0.7 O ₃
(E) Er _0.02 La _0.98 Fe _0.1 Ga _0.9 O ₃
Next, specific production examples of these phosphors will be described.

  The raw materials (g) shown in FIG. 16 were sufficiently mixed in a mortar and then fired under the conditions shown in the figure. After that, unreacted substances were removed with hot water and 2 mol of nitric acid, and each infrared emission fluorescence was obtained. Got the body.

An emission spectrum of (ErY) ₃ (FeAl) ₅ O _{12 as} the sample 16 is shown in FIG. FIG. 18 shows the spectral sensitivity characteristics of the Ge photodiode, and FIG. 19 shows the spectral sensitivity characteristics of the InGaAs photodiode.

  As shown in FIG. 17, the peak of the emission spectrum of the phosphor containing Er is about 1540 nm, whereas the Ge photodiode shown in FIG. 18 and the InGaAs photodiode shown in FIG. 19 have a wavelength in the range of 1400 to 1600 nm. Therefore, it is suitable as a light receiving element of this type, and has a feature that a fine mark such as a barcode pattern can be reliably read even when the reading speed is increased.

  In addition, a PbS photodiode (light receiving sensitivity: about 600 to 1800 nm), a PbSe photodiode (light receiving sensitivity: about 1000 to 4500 nm), and the like can also be used.

  The above-described absorption and emission spectral characteristics can be obtained in the same manner in other infrared light emitting phosphors containing Fe and Er as optically active elements.

Phosphor composition 4
Yb is contained as an optically active element. In addition to this optically active element, at least one element selected from the group of Sc, Ga, Al, In, Y, Bi, Ce, Gd, Lu, and La is contained. Use dull phosphors.

  More specifically, a phosphor having the following general formulas (6) to (8) is used.

Formula _{(6) L 3 M 5 O} 12
Formula (7) LMO ₃
Formula _{(8) L 2 M 4 O} 12
Where L is Yb, at least one element selected from the group of Y, Bi, Ce, Gd, Lu, and La;
M is composed of at least one element selected from the group of Sc, Ga, Al, and In.

The phosphors having the general formulas (6) to (8) are used alone or in the form of a mixture.

  More specifically, the following infrared light emitting phosphors are used.

(A) Yb _0.3 Y _2.7 Al ₅ O ₁₂ (Sample 21)
(B) Yb _0.2 Gd _2.8 Ga _0.5 Al _4.5 O ₁₂ (Sample 22)
(C) Yb _0.4 Y _2.6 Ga ₅ O ₁₂ (Sample 23)
(D) Yb _0.1 La _0.9 AlO ₃ (Sample 24)
(E) Yb _0.05 La _0.95 Ga _0.1 Al _0.9 O ₃ (Sample 25)
The raw materials (g) shown in FIG. 20 were sufficiently mixed in a mortar and then fired under the conditions shown in the figure. After that, unreacted substances were removed with hot water and 2 mol of nitric acid, and each infrared emission fluorescence was obtained. Got the body.

FIG. 21 shows an absorption emission spectrum of Yb _0.3 Y _2.7 Al ₅ O _{12 as} the sample 21.

  As is apparent from this figure, this phosphor has a light absorption peak in the vicinity of 910 to 950 nm, and the phosphor is excited by irradiating light having a wavelength in the vicinity thereof, and has a peak in the vicinity of about 1030 nm. Emits fluorescence.

FIG. 22 is a graph showing changes in the emission intensity of the phosphor when the value of the molar fraction (X) of Yb in the phosphor Yb _X Y _1-X Al ₅ O ₁₂ is variously changed.

As is clear from this figure, since the emission intensity tends to be weak when the molar fraction X of Yb in the phosphor Yb _X Y _1-X Al ₅ O ₁₂ exceeds 0.7, the molar fraction X is It can be seen that high emission intensity can be obtained when the amount is regulated within the range of 0.05 to 0.7, preferably 0.1 to 0.5, and more preferably 0.2 to 0.45.

The surface state of the particles of the Yb _0.3 Y _2.7 Al ₅ O ₁₂ is smooth with no jaggedness when observed with a scanning electron microscope, and has almost the same shape and size without extremely large or small objects. It is round and fruity. Those having a particle size of 1 to 3 μm have a particle size distribution of 60% by weight or more (about 80% by weight) of the whole, and the average shape ratio (minor axis / major axis) of the phosphor particles is 2.0 or less. In addition, there are no extremely long and slender needles and many are rounded, and the dispersibility in the binder is good.

Phosphor composition example 5
For example, a phosphor made of one or more rare earth-containing organic substances selected from the group of Nb, Yb, and Er, on which an organic substance having absorption characteristics with respect to infrared rays having a wavelength in the range of 700 to 1000 nm is supported is used.

  Specifically, the organic substance is at least one organic substance selected from the group consisting of polymethine, anthraquinone, dithiol metal, phthalocyanine, indophenol, and azo dyes.

  More specifically, examples of the polymethine dye include trade names IR-125 and IR-140 manufactured by Kodak Laboratories Chemicals and trade names IR-820B manufactured by Nippon Kayaku Co., Ltd. As an anthraquinone pigment, for example, there is a trade name IR750 manufactured by Nippon Kayaku Co., Ltd. Examples of the dithiol metal salt dye include trade name Tetrabutyl Phosphonium Bis (1,2-benzenethiolate) Nicolate (III) manufactured by Mitsui Toatsu.

  Examples of the phthalocyanine dye include Zn-naphthalocyanine, and other examples include indophenol dyes and azo dyes. Among these, the trade names IR125, IR140, IR750, and IR820B are more preferably used because of their high emission intensity per unit weight.

    It is considered that the reason why the emission intensity at the time of high-speed reading can be further increased from that of the rare earth element by supporting the organic substance having absorption characteristics with respect to light in the infrared region on the rare earth is as follows.

    That is, in the process of returning the energy absorbed by the organic substance having the absorption characteristic to the light in the infrared region to the ground state, it is transferred to one or more rare earth-containing organic substances selected from Nb, Yb and Er. It is considered that this phenomenon occurs in order to sensitize the fluorescent action of these rare earths.

  The phosphor capable of supporting the organic substance having the sensitizing action may have at least one kind of rare earth selected from the group of Nb, Yb and Er, and other elements may be added. There is no problem.

    Further, the one or more rare earth-containing organic substances selected from the group of Nb, Yb and Er may be any substances as long as they form a complex or salt with the rare earth as the organic substance. For example, organic carboxylic acids such as benzoic acid, anisic acid, toluic acid, cinnamic acid and lauric acid, β-diketones such as benzotrifluoroacetone and thenoyltrifluoroacetone, and cyclics such as 15-crown-5 and 18-crown-6 Ethers can be listed.

    Among these, the organic substance to be carried has almost an aromatic ring or a heterocyclic ring, and if the organic substance in one or more rare earth-containing organic substances selected from the group of Nb, Yb and Er is an aromatic carboxylic acid, The interaction between the organic substance and one or more rare earth elements selected from Nb, Yb, and Er becomes stronger, and the carrying capacity is further increased.

    The method for synthesizing the rare earth-containing organic substance is not particularly limited. For example, the synthesis of one or more rare earth-containing aromatic carboxylic acids selected from Nb, Yb, and Er is described in the above-described M.S. D. An ion exchange reaction in an aqueous solution already reported by Taylor et al. N. It can be synthesized by the elimination reaction of isopropoxide in a nonpolar solvent reported by Kapoor et al.

    The amount of the organic substance having absorption characteristics for light in the infrared region with respect to one or more rare earth-containing organic substances selected from Nb, Yb, and Er is not particularly limited, but is preferably 0.001 to 10% by weight. If the organic content is less than 0.001% by weight, the absorption rate of the excitation light source is low, and as a result, the emission of the rare earth-containing organic material becomes weak. On the other hand, if the content of organic matter is more than 10% by weight, the concentration of organic matter having absorption characteristics in the infrared region will be high, and energy will be exchanged between the organic matter. The light emission becomes weak.

    When the infrared phosphor carrying an organic substance is used as an ink, a commonly used binder can be used as the binder, but polyvinyl alcohol (PVA) or acrylic resin is particularly preferable from the viewpoint of the organic substance carrying ability. .

    Solvents may be used as necessary. Solvents that can be used include water, alcohols, ketones, esters, ethers, aromatic hydrocarbons, and aliphatic hydrocarbons alone or in combination. Used.

    A dispersant, an antifoaming agent, a surfactant, a moisturizing agent, a conductivity imparting agent, or the like may be used depending on the case where the infrared phosphor ink composition is applied by various printing methods. Further, various color adjusting dyes, fluorescent dyes and the like may be used in combination as required.

    A specific example of manufacturing the phosphor is as follows.

Example 1
1 part by weight of neodymium cinnamate / ytterbium complex salt is suspended in 20 parts by weight of water and stirred, 0.005 part by weight of anthraquinone dye (trade name: IR750, absorption wavelength peak: 750 nm, manufactured by Nippon Kayaku Co., Ltd.) ) In 1 part by weight of DMF was added dropwise, and after stirring for 1 hour, filtered and dried to obtain an infrared-emitting phosphor.

(Example 2)
While suspending 1 part by weight of ytterbium cinnamate in 20 parts by weight of water and stirring, 0.003 part by weight of a polymethine pigment (trade name IR-820B, absorption wavelength peak made by Nippon Kayaku Co., Ltd .: 820 nm) A solution dissolved in 1 part by weight of DMF was added dropwise, and after stirring for 1 hour, filtered and dried to obtain an infrared emitting phosphor.

Example 3
1 part by weight of ytterbium benzoate is suspended in 20 parts by weight of water, and while stirring, 0.003 part by weight of polymethine dye (Nippon Kayaku Co., Ltd., trade name: IR820B absorption wavelength peak: 820 nm) is 1 part by weight of DMF. The solution dissolved in the part was added dropwise, and after stirring for 1 hour, filtered and dried to obtain an infrared emitting phosphor.

(Comparative Example 1)
LiNd _0.5 Yb _0.5 P ₄ O ₁₂ was pulverized with a ball mill to obtain an infrared emitting phosphor.

(Comparative Example 2)
An infrared-emitting phosphor was obtained in the same manner as in Example 1 except that no anthraquinone dye (trade name: IR750) was used in Example 1.

<< High-speed reading test >>
The infrared light emitting phosphors obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were each formed into a disk shape having a diameter of 5 mm and a thickness of 2 mm. In the high-speed reading test method, a sample is scanned at a speed of 8 m / sec, and a commercially available GaAlAs light emitting diode is used. For the phosphors of Examples 1 to 3, the wavelength of the phosphor is adjusted in accordance with the excitation wavelength of the organic substance used. Detection was performed with a Si-PIN photodetector that irradiates different excitation light and detects 970 nm emission. In addition, an optical filter (trade name IR-94 manufactured by Fuji Photo Film Co., Ltd.) was placed in front of the detector. The results of this high speed reading test are shown in Table 1.

Next, an ink was prepared by a conventional method using a phosphor and a binder.

Example 4
Neodymium cinnamate / ytterbium complex salt 1 part by weight Anthraquinone dye (trade name IR750) 0.005 part by weight PVA 4 parts by weight Water / EtOH (8/2) 20 parts by weight Disperse this composition in a ball mill for 24 hours Then, an ink was prepared and loaded into an ink jet printer to form a latent image by printing.

(Comparative Example 3)
A latent image was formed in the same manner as in Example 4 except that the neodymium cinnamate / ytterbium complex salt was not used.

(Comparative Example 4)
A latent image was formed in the same manner as in Example 4 except that an anthraquinone dye (trade name: IR750) was not used. However, the case where the excitation wavelength was 760 nm was (a), and the case where it was 800 nm was (b).

(Example 5)
Ytterbium cinnamate 1 part by weight Polymethine dye (trade name: IR820) 0.003 part by weight PVA 4 parts by weight Water / EtOH (8/2) 20 parts by weight The composition was dispersed for 24 hours with a ball mill to obtain ink. This was prepared, loaded into an ink jet printer, and a latent image was formed by printing.

(Comparative Example 5)
A latent image was formed in the same manner as in Example 5 except that no polymethine dye (trade name: IR820) was used.

(Comparative Example 6)
A latent image was formed in the same manner as in Example 5 except that ytterbium cinnamate was not used.

(Example 6)
Ytterbium benzoate 1 part by weight Polymethine dye (trade name IR820) 0.005 part by weight PVA 4 parts by weight Water / EtOH (8/2) 20 parts by weight This composition is dispersed for 24 hours with a ball mill to obtain an ink. This was prepared, loaded into an ink jet printer, and a latent image was formed by printing.

(Comparative Example 7)
A latent image was formed in the same manner as in Example 6 except that no polymethine dye (trade name: IR820) was used.

(Comparative Example 8)
A latent image was formed in the same manner as in Example 6 except that ytterbium benzoate was not used.

<< High-speed reading test >>
The high-speed reading test of the printed matter obtained in Examples 4-6 and Comparative Examples 3-7 was performed. In the high-speed reading test method, each sample was scanned at a speed of 8 m / sec, and a commercially available GaAlAs light-emitting diode was used. For the printed materials of Examples 4 to 6, Comparative Examples 3, 6 and 8, the organic materials used were scanned. Detection was performed with a Si-PIN photodetector that irradiates excitation light having a different wavelength corresponding to the excitation wavelength and detects emission at 970 nm. However, an optical filter (trade name IR-94 manufactured by Fuji Photo Film) was placed in front of the detector. The results of the high speed reading test are shown in Table 2 below.

As is clear from Table 1 and Table 2, the phosphors obtained in Examples 1 to 3 can obtain a sufficient light emission output at high speed reading as compared with the phosphors obtained in Comparative Examples 1 and 2. . The phosphors obtained in Examples 1 to 3 can emit light with various excitation wavelengths.

    The inks obtained in Examples 4 to 6 are suitable for inkjet printers.

Phosphor composition example 6
By using a salt composed of at least one of Nd or Yb as an optically active element, at least one oxide of Mo or W, and an alkaline earth metal as a base material, the water resistance of the phosphor is increased. It is a thing.

    The atomic ratio s of the optically active element to at least one oxide of Mo or W is preferably 0 <s ≦ 2, and the atomic ratio t of the alkaline earth metal to the oxide is 0 <t ≦ 3. It is desirable to be.

    More specifically, the phosphor is a compound having the following general formula (9).

General formula (9)
_{(Nd 1 - X Ybx) Y} Q Z (RO 4)
Wherein Q is at least one element selected from the group of Ca, Mg, Sr, Ba,
R is at least one element selected from the group of Mo and W;
X is a numerical value in the range of 0 to 1,
Y is a numerical value greater than 0 and less than 1,
Z is a numerical value greater than 0 and less than or equal to 1.

  Alternatively, the phosphor is a compound having the following general formula (10).

General formula (10)
(Nd _1-X Yb _X ) _2Y Q _8-3Y (RO ₄ ) ₈
Wherein Q is at least one element selected from the group of Ca, Mg, Sr, Ba,
R is at least one element selected from the group of Mo and W;
X is a numerical value in the range of 0 to 1,
Y is a numerical value in the range of more than 0 to 8/3.

  The values of X and Y in the formula are preferably in the range of 0.02 ≦ X ≦ 0.6 and 1/3 ≦ Y ≦ 5/3, respectively. When the X value is less than 0.02, the Yb concentration at the emission center responsible for light emission is low, and when the X value exceeds 0.6, the Nd concentration of the sensitizer that absorbs the excitation light is low. May decrease.

  Also, if the value of Y is less than 1/3, the concentration of Nd and Yb, which are optically active elements, is low, and if the value of Y exceeds 5/3, the concentration of Nd and Yb increases, causing concentration quenching, and the emission intensity is high. It may decrease.

Examples of the alkaline earth metal include Ca, Mg, Sr, and Ba. Among them, Ca is preferable. The content of the alkali metal element is desirably regulated to 10 atomic% or less. Moreover, it is particularly desirable to use Mo as R in the formula.

In manufacturing this phosphor, at least one optically active element of Nd or Yb, at least one oxide of Mo or W, and an alkaline earth metal are mixed, and this is mixed with T ₂ RO ₄ · nH. ₂ O (where T is at least one element selected from the group of Li, Na and K, R is at least one element selected from the group of Mo and W, and n is a numerical value of 0 or more) By putting it in a flux material containing salt and firing it, the flux material is dissolved and removed with a solvent, whereby the particle size can be made extremely fine.

    In particular, Na is preferable as the T of the flux material, and Mo is preferable as the R of the flux material.

    The mixing molar ratio of the flux material to the phosphor material may be 1 or more and 10 or less. If the mixing molar ratio is less than 1, the effect as a flux material is low, and it is difficult to reduce the particle size of the infrared light emitting phosphor. Conversely, if the mixing molar ratio exceeds 10, the cost of the material is large due to the size of the crucible and the like. Becomes higher.

    The phosphor obtained by this method is very fine particles having an average particle size of 1 μm or less, and is also suitable for a printing method such as an ink jet printer or an ink ribbon.

    The characteristics of this phosphor are that the time until the afterglow after stopping the irradiation of the excitation light becomes 10% of the emission output is within 500 μsec, and the emission is identified by pulsed light excitation with a period of 1 msec. It is suitable for a system that identifies light emission at a traveling speed of 5 m / sec or more.

    Further, this phosphor has excellent water resistance such that the solubility in water when immersed in water for 20 hours is 2% by weight or less.

    Such a phosphor can be easily formed into a thermal transfer ink ribbon by applying an ink dispersed in a transparent binder that disperses and holds the phosphor to a tape-like substrate, and as an ink for an ink jet printer. It can also be used. Furthermore, since this fluorescent substance has the outstanding water resistance, it can also be utilized as a coating material.

    As the binder, resins such as wax, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polyester, polyurethane, and carbonate can be used. Moreover, you may add a plasticizer, surfactant, etc. suitably as needed.

According to the fact that the present inventors have confirmed by experiments the water resistance of this phosphor, for example, when the anion of the base material is MoO ₄ ²⁻ , the cation is Na ⁺ which is an alkali metal as in the conventional product. A phosphor obtained by activating a rare earth element on a base material Na ₂ MoO ₄ and a base material CaMoO _{4 in} which the cation is Ca ² which is an alkaline earth metal as in the present invention. When the solubility in water is compared with a phosphor activated with a rare earth element, about 10% by weight of the phosphor dissolves only by being immersed in water for about 20 hours in the conventional product. The product has excellent water resistance that it hardly dissolves even after immersion for 500 hours.

Next, a specific example will be described.
(1) Preparation of powder raw material 10 types of phosphors are produced as follows, and the form of powder particles, the average particle size (average particle diameter), the emission wavelength of the phosphor, and the remaining after the excitation light is stopped. The afterglow time until the light reaches 10% of the light emission output, and the recovery rate expressed as a percentage by measuring the weight when 100 parts by weight of the phosphor is immersed in water, taken out after 500 hours and dried, are measured. The results are shown in Table 3 below.

(Example 7)
Nd ₂ O ₃ 0.9 mole, a 0.1 mole Yb ₂ O _3, the CaCO ₃ 5 moles, the MoO ₃ and 8 moles collected, which was thoroughly mixed and ground, electricity transferred to an alumina crucible The furnace was put into a furnace, heated to 750 ° C. at a heating rate of about 180 ° C./hr, and fired at 750 ° C. for 2 hours. Firing After completion cooled, and pulverized in a mortar, to obtain a phosphor _{Nd 1.8 Yb 0.2 Ca 5 (MoO} 4) 8.

(Example 8)
Nd ₂ O ₃ 0.9 mol, Yb ₂ O ₃ 0.1 mole, 21 mole CaCO _3, the MoO ₃ and 24 mol collected, which was thoroughly mixed and ground, electricity transferred to an alumina crucible The furnace was put into a furnace, heated to 750 ° C. at a heating rate of about 180 ° C./hr, and fired at 750 ° C. for 2 hours. Firing After completion cooled, and pulverized in a mortar, to obtain a phosphor _{Nd 1.8 Yb 0.2 Ca 21 (MoO} 4) 24.

Example 9
4.5 mol of Nd ₂ O ₃ , 0.5 mol of Yb ₂ O ₃ , 9 mol of CaCO ₃ , and 24 mol of MoO ₃ were sampled, mixed and pulverized sufficiently, transferred to an alumina crucible, and electricity The furnace was put into a furnace, heated to 750 ° C. at a heating rate of about 180 ° C./hr, and fired at 750 ° C. for 2 hours. Firing After completion was cooled to obtain a phosphor _{Nd 9 YbCa 9 (MoO 4)} 24 was ground in a mortar.

(Example 10)
Nd ₂ O ₃ and 4.5 mol, Yb ₂ O ₃ 0.5 mole, CaCO ₃ to 9 moles, WO ₃ and was 24 mol collected, which was thoroughly mixed and ground, electricity transferred to an alumina crucible It put into the furnace, heated up to 1000 degreeC with the temperature increase rate of about 250 degreeC / hr, and baked at 1000 degreeC for 2 hours. Firing After completion was cooled to obtain an infrared light emitting phosphor _{Nd 9 YbCa 9 (WO 4)} 24 was ground in a mortar.

(Example 11)
1 mol of Nd ₂ O ₃ , 21 mol of CaCO ₃ and 24 mol of MoO ₃ were sampled, mixed and pulverized sufficiently, transferred to an alumina crucible, put into an electric furnace, and heated at about 180 ° C./hr. The temperature was raised to 750 ° C. at a temperature rate, and firing was performed at 750 ° C. for 2 hours. Firing After completion was cooled to obtain a phosphor _{Nd 2 Ca 21 (MoO 4)} 24 was ground in a mortar.

(Example 12)
0.9 mol Nd ₂ O _3, 0.1 mol Yb ₂ O _3, the CaCO ₃ 5 moles, the MoO ₃ and 8 moles collected, which in the Na ₂ MoO ₄ · 2H ₂ O as a powder flux material The mixture was sufficiently mixed and ground at a molar ratio of 1: 8, transferred to an alumina crucible, placed in an electric furnace, heated to 750 ° C. at a heating rate of about 180 ° C./hr, and fired at 750 ° C. for 2 hours. After completion of the firing, the product was cooled and subjected to ultrasonic cleaning in pure water for 1 hour to remove the flux material and dried at 120 ° C. for 2 hours to obtain phosphor Nd _1.8 Yb _0.2 Ca ₅ (MoO ₄ ) ₈ .

    FIG. 23 shows an emission spectrum of the phosphor, FIG. 24 shows a response waveform to pulsed light excitation, and FIG. 25 shows a photograph of the particle structure of the phosphor.

Further, 100 parts by weight of the phosphor was immersed in water, taken out after 500 hours and dried, and the emission intensity, response speed, and particle shape of the phosphor were not changed. Further, when this phosphor is immersed in 1N NaOH and CH ₃ COOH for 24 hours, the solubility is 0.9% by weight, and the emission intensity, response speed and particle shape of the phosphor taken out from the immersion liquid and dried are not changed. There wasn't.

(Example 13)
Nd ₃ O ₃ 0.9 mol, Yb ₃ O ₃ 0.1 mol of CaCO ₃ 5 moles, the MoO ₃ and 8 moles collected, which in the Na ₂ WO ₄ · 2H ₂ O as a powder flux material The mixture was sufficiently mixed and ground at a molar ratio of 1: 6, transferred to an alumina crucible, placed in an electric furnace, heated to 750 ° C. at a temperature increase rate of about 180 ° C./hr, and baked at 750 ° C. for 2 hours. After completion of the firing, the product was cooled and subjected to ultrasonic cleaning in pure water for 1 hour to remove the flux material and dried at 120 ° C. for 2 hours to obtain a phosphor Nd _1.8 Yb _0.2 Ca ₅ (MoO ₄ ) ₈ .

(Example 14)
Nd ₂ O ₃ 0.9 mol, Yb ₂ O ₃ 0.1 mol of CaCO ₃ 5 moles, the MoO ₃ and 8 moles taken, this powder flux material as K ₂ WO ₄ in a molar ratio of 1: The mixture was sufficiently mixed and pulverized in No. 6, transferred to an alumina crucible, placed in an electric furnace, heated to 750 ° C. at a heating rate of about 180 ° C./hr, and fired at 750 ° C. for 2 hours. After completion of the firing, the product was cooled and subjected to ultrasonic cleaning in pure water for 1 hour to remove the flux material and dried at 120 ° C. for 2 hours to obtain a phosphor Nd _1.8 Yb _0.2 Ca ₅ (MoO ₄ ) ₈ .

(Comparative Example 9)
Nd ₂ O ₃ 0.9 mol, Yb ₂ O ₃ 0.1 mol, Na ₂ CO ₃ to 5 moles, and the MoO ₃ and 8 moles collected, which was thoroughly mixed and pulverized, was transferred to an alumina crucible And heated to 650 ° C. at a rate of temperature increase of about 160 ° C./hr and baked at 650 ° C. for 2 hours. Firing After completion was cooled to obtain a phosphor _{Nd 0.9 Yb 0.1 Na 5 (MoO} 4) 4 was pulverized in a mortar.

(Comparative Example 10)
Nd ₂ O ₃ 0.2 mol, Yb ₂ O ₃ 0.2 mol, Y ₂ O ₃ 0.6 mol, and LiH ₂ PO ₄ 12 mol were sampled and mixed sufficiently and pulverized. It moved to the crucible made, put into the electric furnace, and baked at 700 degreeC for 2 hours. After the completion of firing, the mixture was cooled, pickled with 1N HNO ₃ , further washed with pure water, and then dried to obtain phosphor Nd _X Yb _Y Y _1-XY PO ₄ .

As apparent from Table 3, the conventional phosphor has a slow response speed and is not suitable for high-speed reading such as short-pulse light excitation and high-speed scan, but the phosphor of the present invention has a high response speed and short-pulse light excitation. It can be seen that high-speed reading such as high-speed scanning is possible and durability is high, and in particular, those of Examples 12 to 14 can obtain ultrafine-particle phosphors having a particle diameter of 1 μm or less suitable for various printing.

    In addition, FIG. 26 shows the change over time in the recovery rate when the phosphors of Example 12 and Comparative Example 9 were immersed in pure water. In this method, 100 parts by weight of the phosphor is immersed in water, taken out after a lapse of a certain period of time and dried, and the weight ratio is measured and expressed as a percentage.

    As can be seen from this figure, in Comparative Example 9, 10% by weight or more of the phosphor was eluted, whereas in Example 12, it was hardly eluted and the water resistance was excellent. It has been confirmed that the phosphors obtained in other examples of the present invention are also excellent in water resistance.

    75 parts by weight of the phosphor prepared in Example 12 was dispersed in a transparent binder that is a mixture of 15 parts by weight of wax, 5 parts by weight of polyester, and 5 parts by weight of polyurethane to prepare an ink for printing the phosphor. This ink was applied to a tape-like polyethylene terephthalate having a thickness of 50 μm and a width of 1 cm so as to have a dry thickness of 5 μm to produce an ink ribbon for thermal transfer printing.

    Using this ink ribbon, a bar code representing a 10-digit numerical value is printed, which is excited by pulsed infrared light having a wavelength of 810 nm with a period of 0.8 msec, and afterglow at a traveling speed of 0.9 m / sec. As a result, the 10-digit numerical information printed by the bar code could be read reliably.

2. [Printing method of phosphor composition and latent image mark forming member]
As a printing method of each phosphor composition described above, an ink jet recording method is suitable for high-speed printing. As this ink jet recording method, for example, (a) an electric field control method for discharging ink using electrostatic attraction,
(B) Drop-on-demand method (pressure pulse method) that ejects ink using the wave pressure of the piezo element;
(C) A bubble jet method in which ink is ejected using pressure generated by forming and growing bubbles by high heat is applicable.

    FIG. 27 is a diagram illustrating the principle for explaining the electric field control method. In this electric field control method, marks or characters to be printed are divided into pixels in a dot matrix, ink particles are charged with a voltage proportional to position information of each pixel, and then deflected by an electrostatic field to be detected. This is a printing method.

    The principle of this electric field control method will be described with reference to FIG. The ink 2 stored in the ink bottle 1 is pressurized by the supply pump 3, adjusted to a constant pressure by the pressure regulating valve 4, and ejected from the nozzle 5.

    The electrostrictive element 6 installed in the nozzle 5 is vibrated at a constant frequency by the excitation source 7. The ink ejected as a liquid column from the nozzle 5 becomes ink particles having a certain size in synchronization with the vibration cycle of the electrostrictive element 6.

    A voltage corresponding to the information signal to be recorded is applied to the charging electrode 8 provided at a position where the ink is atomized, and the charge amount for each ink particle is controlled in accordance with the timing of particle formation.

    When the ink particles pass between the deflection electrodes 9 and 9 to which a predetermined voltage is applied, the ink particles are deflected according to the charge amount and reach the member to be printed. A latent image (mark) having a size determined by the deflection and the relative movement speed between the nozzle 5 and the member is printed in the form of dots on the surface of the member to form the latent image forming member 10.

    Ink that has not been used for printing is collected by the gutter 11 without being deflected, and is collected in the ink bottle 1 by the collection pump 12.

    Any member such as securities, slips, cards, books, various parts, and various products can be used as the member on which the phosphor composition is printed.

    As a result of various studies on the content of phosphor particles in the printed layer, the desired emission intensity cannot be obtained when the content of phosphor particles is 1% by weight or less. As the content of the phosphor particles increases, the emission intensity gradually increases. However, when the content exceeds 50% by weight, the aggregation and overlap of the phosphor particles substantially increase, and the emission intensity does not increase so much. When the content of selenium exceeds 30% by weight, the presence of the printed layer is conspicuous, and particularly when phosphor particles made of an inorganic compound and having a relatively large particle size are used, printability such as inkjet printing and screen printing decreases. To do.

    Therefore, by controlling the content of the phosphor particles in the printing layer to be more than 1% by weight and less than 30% by weight, the desired emission intensity is maintained, and the presence of the printing layer is not noticeable. The appearance of the forming member is not impaired, and the printability is good. In particular, the content is suitable for those using phosphor fine particles having an average particle size of 4 μm or less, more preferably 2 μm or less, as described above.

    Further, as a result of examining the relationship between the thickness of the printing layer and the size of the phosphor particles to be used, the thickness of the printing layer is regulated within 35 times, preferably within 25 times the average particle size of the phosphor particles to be used. However, the presence of the printed layer is hardly recognized (not conspicuous) even by touch, and the appearance of the latent image forming member is not impaired. Therefore, when the average particle size of the phosphor particles is 4 μm, the thickness of the printing layer may be 140 μm or less, and when the average particle size is 2 μm, the thickness of the printing layer may be 70 μm or less.

    As a result of examining the light transmittance of the binder for dispersing and holding the phosphor fine particles, the excitation light and the light transmittance with respect to fluorescence are 80% or more, preferably 90% or more. As a result, it was found that the fluorescent light emitted inside the printed layer was efficiently emitted to the outside, so that the light emission output was increased and the latent image was reliably detected.

    Next, the present inventors examined the surface state of the printed layer. Comparison of light emission output between the case where a printed layer is formed by applying a paint containing phosphor fine particles on a synthetic resin film and the case where a printed layer is formed by applying a paint having the same composition on paper. As a result, the output was larger when applied on paper.

    When the surface state of the printed layer formed on the above synthetic resin film is observed, it is very smooth, whereas the printed layer coated on the paper has fine irregularities on the surface. It is considered that the excitation light irradiated due to the fine unevenness is not regularly reflected, and a large light emission output can be obtained due to the activation of the phosphor. In particular, when the average size of the phosphor particles is smaller than the diameter of the fibers constituting the paper (for example, the average size is about 0.2 μm), the phosphor particles have various angles on the surface of the fibers entangled irregularly and non-directionally. Since it adheres, the excitation efficiency of the phosphor is high.

    As will be described later, when the printed layer is formed on a delivery item such as mail or courier, or on a card such as a prepaid card or a transit card, the printed layer should be inconspicuous in appearance. In order to make the print layer inconspicuous, there is a means for limiting the thickness of the print layer as described above, but there is also a method for limiting the visible light absorption rate of the print layer.

    The main components of the printing layer are a binder and phosphor particles, and those having a low visible light absorptivity are used as these materials. As a result, the visible light absorptivity of the printed layer is 20% or less, preferably 10% or less. It has been found that the printed layer becomes almost colorless and transparent by restricting the thickness of the latent image forming member to the latent image forming member.

    In addition, the latent image forming member according to the embodiment of the present invention may cause the transfer paper surface to become dirty due to the formation of the print layer because the printed layer portion is not copied or hardly noticeable even when copied by electrophotography. There is no worry to do.

A specific example in which a latent image made of a phosphor composition is formed on a mail is shown in FIG.
As shown in the figure, for example, a stamp 14 is pasted on the surface of a postal matter 13 such as a sealed letter, a postcard, a postal parcel, a postal code 15 is written, a destination address 16 and an address 17 are described. In addition to these, for example, bar code information relating to the destination address is printed at a predetermined position by the Ingjet recording method to form the print layer 18. Since this bar code information is a latent image, there is no fear that the appearance of the mail piece 13 will be damaged.

    FIG. 29 is a diagram showing another example of the postal item 13. In this example, the delivery address is predetermined, and the label 19 on which the barcode information related to the delivery address is printed by the phosphor composition is shipped. A person is holding. When the postal matter 13 is shipped, the label 19 is attached to a predetermined position of the postal matter 13 and submitted to the post office. In addition, since the label 19 sticking position is different for each mail piece 13 and hinders reading of information, the label sticking position is printed on the surface of the mail piece 13, and the label 19 is stuck to the position. It is supposed to be.

    In this example, the postal matter has been described, but the present invention can also be applied to other deliveries such as a home delivery service and an in-house mail service.

    In this example, information on the destination address is printed by the phosphor composition, but a destination name, a sender address, a sender name, or other necessary information can also be printed.

    FIG. 30 is a flowchart for explaining the process of adding the barcode information and reading the information.

    The mail items 13 collected at the post office are first put into the direction aligning device 20 and the direction thereof is aligned. And since the postal item 13 has the label 19 attached and the nonexistent one mixed, the sorting device 21 sorts the label 19 into the pasted item and the unlabeled item. . This sorting of the postal matter 13 is judged to be the postal matter 13 to which the label 19 is attached if the place where the label 19 is attached is irradiated with infrared rays of a predetermined wavelength region and emits fluorescence. If the fluorescent light is not received, it is determined that the mail piece 13 is not attached with the label 19 and the both are sorted.

    The postal item 13 to which the label 19 is not attached is sent to the OCR 22, and the postal code 15 and the destination address 16 described on the postal item 13 are optically read. Based on the read information, Bar code information regarding the delivery address is printed at a predetermined position on the postal matter 13 by the ink jet printer (IJP) 23.

    The postal matter 13 printed in this way is sent to the bar code sorting device 24, optically reading the bar code information, and automatically sorting the postal matter 13 based on the bar code information.

    Since the postal matter 13 to which the label 19 is attached does not need to print barcode information, the postal matter 13 is sent directly to the bar code sorting device 24 and sorted.

    The bar code sorting device 24 mainly includes a reading device that optically reads bar code information and a sorting device that sorts the postal matter 13 based on the read bar code information.

(Example 1 of optical reading apparatus)
FIG. 31 is a diagram showing a schematic configuration of the reading device 25. The reading device 25 is mainly composed of a reader optical system and a reading circuit.

    The reader optical system includes a semiconductor laser drive circuit 26, a semiconductor laser 27, a lens 28, a total reflection mirror 29, plano-convex lenses 30, 31, a slit 32, a filter 33, and a photodiode 34. ing.

    The excitation light 60 emitted from the semiconductor laser 27 is focused to a diameter of about 1 mm by a lens 28, and passes through a through hole 35 having a diameter of about 2 mm provided in the center of a mirror 29 as shown in FIGS. Irradiated perpendicularly to the plane of the postal matter 13 which is the latent image forming member 10 through the lens 30.

    When the excitation light 60 is emitted to the mirror 29 side without being focused, a part of the excitation light 60 is cut by the outer peripheral portion of the through-hole 35, so that the light amount (excitation energy) of the excitation light 60 reaching the postal matter 13 side is reduced. Since it substantially decreases and as a result the light emission output becomes small, it is necessary to regulate the focusing diameter of the excitation light 60 to be equal to or smaller than the diameter of the through hole 35. In this embodiment, in consideration of an error in the component mounting position, the focusing diameter of the excitation light 60 is set to 1 mm with respect to the diameter of the through hole 35 being 2 mm.

    The postal matter 13 is conveyed in the direction of the arrow at a high speed of 4 m / sec, for example, and irradiates the bar-shaped print layer 18 therebetween, excites the phosphor, and receives the fluorescence by the first plano-convex lens 30. The received light is reflected by the mirror 29, converged by the second plano-convex lens 31, passes through the slit member 32 and the filter 33, and is received by the photodiode 34.

    The reading circuit includes a detection circuit 36 including an amplification circuit and a filter circuit, a binarization processing circuit 37, a decoding circuit 38, a serial interface 39, and a personal computer 40 for data processing. .

    A half mirror can be used in place of the mirror 29. However, in the case of a half mirror, only half of the excitation light can be irradiated to the postal item 13 side, and only half of the fluorescence is directed to the photodiode 34 side. It cannot be reflected, which reduces the output. In the present invention, in order to increase the amount of reflected light and to read the bar code information of the postal item 13 at high speed and accurately, a mirror 29 having a high reflectivity with a fine through hole 35 and a reflectivity exceeding 50% is used. is doing. The mirror 29 in this embodiment uses a front mirror mirror formed by evaporating aluminum or the like on the surface of glass.

    Also, the mail items 13 have various thicknesses, and there are fluctuations in the direction of the optical axis of the transport system. In order to cope with this, the light passing through the mirror 29 is incident substantially perpendicular to the plane of the mail piece 13. In this way, even if the thickness of the postal matter 13 fluctuates or shakes with respect to the optical axis direction of the transport system, the bar code information can be read with almost no influence.

    FIG. 33 is a view for explaining the function and problems of the slit member 32. In this example, a slit member 32 is disposed in front of the first plano-convex lens 30, and the fluorescent light 61 emitted from the printed layer 18 of the postal matter 13 (latent image forming member 10) passes through the slit 32 a of the slit member 32. 1 is guided to the plano-convex lens 30 side.

    As shown by a solid line in the figure, the fluorescence 61 emitted when the printing layer 18 faces the slit 32a is received through the slit member 32. However, the post 13 (latent image forming member 10) conveys the slit 32a. A slit member 32 is provided so as to cut off the fluorescent light 61 (indicated by a dotted line) emitted from the printed layer 18 that passes below. Thus, in order to select only the fluorescent light 61 from the printing layer 18 facing the slit 32a, the slit member 32 is arranged as close as possible to the conveying means 62 of the postal matter 13 (latent image forming member 10). Has been.

    For this reason, when the thick postal matter 13 is conveyed, the leading end of the postal matter 13 hits the slit member 32 and stops, or the slit member 32 is damaged.

    Therefore, in the present invention, as shown in FIG. 31, the slit member 32 is removed from the transport path of the postal matter 13 and is disposed between the second plano-convex lens 31 and the light receiving element 34. In this way, while having the function of the slit member 32, the space between the conveying means 62 and the first plano-convex lens 30 can be made large, and the thick mail piece 13 can also pass through.

34 and 35 are diagrams for explaining the relationship between the radiation pattern of the laser beam output from the semiconductor laser and the barcode pattern. As shown in FIG. 34, the semiconductor chip 41 includes an Al electrode 42, a p-electrode 43, a p-GaAs substrate 44, a current confinement layer 45 made of n-GaAs, and a clad layer 46 made of p-Ga _1-X Al _X As. , An active layer 47 made of p-Ga _{1 -Y} Al _Y As, a clad layer 48 made of n-Ga _{1 -X} Al _X As, a cap layer 49 made of n-GaAs, and an n-electrode 50. ing.

    The laser light radiation pattern 51 output from the semiconductor chip 41 has an elliptical shape. Conventionally, the elliptical radiation pattern 51 is formed into a circular shape and used for barcode detection. In the present invention, as shown in FIG. 35, the barcode-like printed layer 18 printed on the latent image forming member is used. Is applied to the printed layer 18 such that the longitudinal direction of the radiating pattern 51 faces the longitudinal direction of the radiation pattern 51.

    In this way, the irradiation area with respect to the printed layer 18 is increased as compared with those using a circular radiation pattern, and as a result, a large output can be obtained and suitable for high-speed reading.

    The postal matter 13 passes under the optical reader while being transported by a transporting means 62 such as a belt conveyor with a guide, for example, but the postal matter 13 is inclined at a maximum of about 10 degrees even if there is a guide. There is.

  FIG. 36 is a view showing a state in which the extremely fine printed layer 18 and the radiation pattern 51 are opposed to each other when the mail piece 13 is inclined (inclination angle: about 7 degrees). At this time, the short axis 64 of the radiation pattern 51 is excessive. If it is long, the adjacent printed layer 18 may be read. As a result of various studies by the present inventors, when the ratio of the minor axis 64 to the major axis 63 (major axis / minor axis) of the radiation pattern 51 exceeds 15, the adjacent print layer when it is relatively inclined as described above. Since 18 information is sometimes read, it has been clarified that the ratio of the short axis 64 to the long axis 63 (long axis / short axis) of the radiation pattern 51 should be regulated to 15 or less.

(Example 2 of optical reader)
FIGS. 37 and 38 are diagrams showing a second embodiment of a mirror and an optical reading apparatus using the mirror.

    In the case of this example, as shown in FIG. 37, a slit 53 is formed in the periphery of the high reflectivity mirror 29 having a reflectivity exceeding 50%. As shown in FIG. 38, the excitation light 60 from the semiconductor laser 27 is irradiated to the printed layer 18 of the mail piece 13 through the slit 53. The radiation pattern projected onto the mail piece 13 through the slit 53 is shown in FIG. Is directed to the longitudinal direction of the barcode of the printing layer 18. By doing so, it is possible to irradiate most of the longitudinal direction of the barcode as in the above-described elliptical radiation pattern, and a large output can be obtained.

(Example 3 of optical reader)
39 and 40 are diagrams showing another example of use of the infrared light emitting phosphor. As shown in FIG. 39, three print layers 18a, 18b, and 18c are provided at predetermined positions of the securities 55, and each of the print layers 18a to 18c contains phosphors having emission spectra different from each other.

    Then, semiconductor lasers 27a, 27b, and 27c that irradiate the respective print layers 18a to 18c with predetermined excitation light, and photodiodes 34a, 34b, and 34c that receive fluorescence emitted from the print layers 18a to 18c, respectively. They are arranged in pairs.

Examples of the phosphors having different emission spectra include Nd _0.1 Yb _0.1 Y _0.8 PO ₄ having the emission spectrum shown in FIG. 13, Yb _0.1 Y _0.9 PO ₄ having the emission spectrum shown in FIG. 14, and the emission shown in FIG. Er _0.2 Y _2.8 Fe _1.5 Al _3.5 O ₁₂ or the like having a spectrum is appropriately selected and used.

    Therefore, when the above-described phosphors are used for the print layers 18a to 18c, the respective securities 55 are received by the photodiodes 34a, 34b, 34c, so that the securities 55 are determined to be authentic. If there is a photodiode 34 that does not receive any of the photodiodes 34a, 34b, 34c, it is determined that the securities 55 are not authentic.

    In the example of FIG. 39, the case where the phosphors having different emission spectra are used individually is shown. However, as shown in FIG. 40, the printing layer 18 can be formed by mixing the phosphors having different emission spectra.

    In this case, the print layer 18 is irradiated with excitation light from the semiconductor lasers 27a, 27b, and 27c, and the fluorescence emitted from the print layer 18 is received by the photodiodes 34a, 34b, and 34c, respectively. 39 and 40, optical filters for transmitting light components to be received and blocking light of other wavelengths are attached to the light receiving surfaces of the photodiodes 34a, 34b, and 34c.

(Example 4 of optical reader)
Shows the emission intensity characteristics of the long phosphors fall time t _d in (c) of FIG. 3, the phosphor having such characteristics is suitable for the detection of information using afterglow.

    FIG. 41 is a timing chart showing the light emission timing of the light emitting element and the output state of the light receiving element when detecting information using afterglow.

As shown in FIG. 6A, the light emitting element is turned on and off at time intervals in which the lighting time T ₁ and the light extinguishing time T ₂ are approximately equal, and intermittently irradiates the print layer with excitation light. In the figure, S ₁ indicates a lighting signal of the light emitting element.

The phosphor in the printed layer is excited by the light irradiation from the light emitting element, and the output increases until the irradiation from the light emitting element is completed as shown in FIG. And even if irradiation from a light emitting element stops, a light receiving element receives afterglow emitted from a printing layer. Therefore afterglow decreases with time, set in advance a reference value Vs, by comparison with the reference value Vs, the rectangular signal S ₃ obtained after irradiation from the light emitting element is stopped.

    Therefore, by repeatedly turning on and off the light emitting element every minute time, the code information of the barcode pattern can be optically read.

    In this way, the detection method using the afterglow of the phosphor detects the fluorescence without using reflected optical light because the light emitting element is turned off when reading information, and therefore without using an expensive optical filter. Therefore, it is possible to provide a small-sized and low-cost optical reader.

    42 and 43 are diagrams for explaining an optical reading apparatus suitable for the afterglow detection. As shown in FIG. 42, the optical reading apparatus has an irradiation pulse frequency selection switch 70, a pulse oscillation circuit 71, a transistor (Tr) 72, a laser drive current limiting resistor (R) 73, and a drive having an automatic power control (APC) function. A circuit 74, a semiconductor laser diode 75, a condenser lens 76, a light receiving circuit 77, a laser output adjustment volume (VR) 78, a hold circuit 79, and the like are provided.

    Next, the operation of this optical reader will be described. First, an appropriate irradiation pulse frequency is selected by the irradiation pulse frequency selection switch 70, and a pulse corresponding to the selection is generated by the pulse oscillation circuit 71 and output as a clock (CLK) signal.

    The transistor (Tr) 72 is turned on / off by this CLK signal, and the supply of the laser drive current Iout output from the APC drive circuit 74 to the semiconductor laser diode 75 is controlled. The laser drive current Iout is limited by the laser drive current limiting resistor (R) 73 so that the transistor (Tr) 72 and the semiconductor laser diode 75 are not destroyed.

    The excitation light 60 output in a pulse form from the semiconductor laser diode 75 irradiates the print layer 18 on the latent image forming member 10 through the condenser lens 76 and emits from the print layer 18 when the semiconductor laser diode 75 is turned off. The fluorescence 61 (afterglow) is detected by the light receiving circuit 77.

    In order to obtain constant pulsed excitation light from the semiconductor laser diode 75 at a predetermined interval, the APC drive circuit 74 detects the monitor light of the semiconductor laser diode 75 and applies feedback control to the laser drive current Iout.

    When this monitor light is detected, it is obtained from the semiconductor laser diode 75 as the monitor current Iin. The peak of the monitor current Iin when the semiconductor laser diode 75 is on is detected or sampled by the hold circuit 79, and the monitor current Iin is detected when the semiconductor laser diode 75 is off. By holding the state, the excitation light of the semiconductor laser diode 75 is controlled so that the phosphor can be smoothly excited when the next semiconductor laser diode 75 is turned on. The output of the semiconductor laser diode 75 required for exciting the phosphor is previously adjusted by the laser output adjustment volume (VR) 78.

    FIG. 43 is a diagram showing the configuration of the semiconductor laser diode 75, which includes a semiconductor laser 80 that outputs excitation light and a monitoring photodiode 81 that receives the excitation light output from the semiconductor laser 80.

    If an LED is used as the excitation light source and pulsed excitation light is output by switching with a transistor, it is difficult to obtain sufficient emission intensity at the time of detection even if the excitation light is reduced using a condensing lens. The optical path length for is limited.

    42 and 43, on the other hand, a semiconductor laser diode having excellent condensing properties and directivity is used as the excitation light source. Therefore, even if the optical path length of the reading device is increased, it is sufficient for detection. Luminous intensity can be obtained.

    Further, by using a semiconductor laser diode drive circuit having an APC function, the influence of the temperature change of the excitation light can be reduced or eliminated, and the reading reliability is improved.

    Furthermore, the monitor current when the semiconductor laser diode is turned on is held, and the drive circuit of the semiconductor laser diode is feedback-controlled based on this value, so that the APC function is exhibited regardless of the pulse frequency fluctuation and the duty ratio. Excitation can be performed smoothly and reading reliability is improved.

(Example 5 of optical reader)
Next, an optical reading apparatus according to Embodiment 5 will be described.
For example, as shown in FIG. 44, a card 80 such as a cash card uses, for example, a white polyester film as a base material 81, and an underlayer of an arbitrary design whose reflectance is adjusted in advance on the upper surface side of the base material 81 A magnetic layer 83 for recording main information in a rewritable manner is formed by printing 82 and applying a magnetic paint on the lower surface side. Further, a mark 84 containing a phosphor is printed on the upper surface side underlayer 82, whereby the sub information for security is fixedly recorded.

    The mark 84 is an invisible state, that is, a latent image composed of a phosphor that generates fluorescence 86 having a wavelength different from the center wavelength corresponding to the irradiation of the irradiation light 85 in the infrared region, for example, It has a thin bar code shape orthogonal to the longitudinal direction of the card 80. With the formation of the mark 14, predetermined sub information for security such as a card issuing store code or a personal identification number is recorded on the card 80.

    The barcode formed as the mark 84 includes a background portion 87 and a data portion 89b composed of a plurality of bars 88 in the conventional barcode illustrated in FIG. 45 (d) as shown in FIG. Introducing portions 91 and 91a sandwiching at least the gap 90 provided between the bars 88 and the front and rear of the data portion 89 in the scanning direction are formed of a phosphor layer.

    By adopting such a configuration, regardless of which direction the data portion 89 is scanned, the introduction portion 91 that is sufficiently longer than the width of each bar 88 and the gap 90 constituting the data portion 89 is always passed before and after that. The position of the data portion 89 can be easily detected. Further, the contrast in the entire area of the data portion 89 is made uniform to prevent erroneous detection of the thickness of the first bar 88a at the scanning start position.

    As the phosphor constituting the mark 84, the various phosphors and rare earth elements such as neodymium (Nd), ytterbium (Yb), eurobium (Eu), thulium (Tm), praseodymium (Pr), dysprosium (Dy), etc. Alternatively, a compound in which a mixture thereof is used as an optically active element and the optically active element includes an oxide such as phosphate, molybdate, or tungstate in the base is used. However, as long as it generates fluorescence 86 having afterglow by irradiating with light having an arbitrary wavelength, the material can be changed as appropriate.

In this embodiment, when a mark 84 is formed by printing a fluorescent paint containing a phosphor such as Li (Nd _0.9 Yb _0.1 ) P 4 O ₁₂ and irradiated with excitation light in the near-infrared region having a wavelength of about 800 nm. Infrared region fluorescence 86 having a peak value at a wavelength of about 1000 nm is generated, and afterglow characteristics of about 400 to 600 μsec until the light intensity is attenuated to 10% when excitation light irradiation is stopped. Have.

    As shown in FIG. 46, the optical reading apparatus according to the present embodiment is emitted from the traveling unit 92 of the card 80, the light irradiation unit 93 for the card 80 conveyed by the traveling unit 92, and the position where the light is irradiated. From the photoelectric conversion unit 95 that takes in the light 94 to be converted into an electrical signal, the mark detection unit 96 that detects the mark signal S4 corresponding to the formation position of the mark 84 from the converted electrical signal, and the detected mark signal S4 A data processing unit 97 for determining the data content on the card 80.

    The traveling unit 92 is transported at a constant speed of, for example, about 200 to 400 mm per second while supporting both side edges of the card 80 by rollers 99 that are rotationally driven by a motor drive circuit 98 corresponding to the insertion timing of the card 80. Thus, the barcode-shaped mark 84 formed on the upper surface side of the card 80 passes below the light irradiation unit 93 and the photoelectric conversion unit 95. Data relating to the operation timing of the motor drive circuit 98 is sent to the data processing section 97 to inform the time required for data processing for determining the mark contents.

    The light irradiation unit 93 includes a light source driving power source 100 that outputs a predetermined DC voltage corresponding to the detection timing of the mark 84 and a light source 101 that generates predetermined light 85 when the light source driving power source 100 is energized. Is done.

    In the light emission source 101, a light guide 103 made of glass fiber is attached to a light emission portion of a light emitting element 102 such as a light emitting diode that generates near infrared rays having a light emission center wavelength of about 800 nm as shown in FIG. The front end of the light guide 103 is brought close to the surface of the card 80 by a distance of 2 mm or less, and the entire light guide 103 is 45 to 45 mm from the horizontal direction on a plane orthogonal to the transition direction of the mark 84. An inclination angle (θ1) of 60 ° is provided.

    The photoelectric conversion unit 95 that converts light 94 emitted from the light irradiation position on the card 80 into an electric signal includes a detector 104 that converts incident light into current, and AC amplification that amplifies after converting the current into voltage. The circuit 105 is configured.

    As shown in FIG. 44, the detector 104 selectively selects light having a wavelength of fluorescence 86 generated from the mark 84 on the light receiving surface of a light receiving element 106 such as a photocell or photodiode having light receiving sensitivity in the infrared region. A light guide 108 substantially the same as that of the light emission source 101 is fixed through an optical filter 107 that passes therethrough.

    By bringing the tip of the light guide 108 on the detector 104 side closer to the tip of the light guide 103 and providing a tilt angle (θ2) of, for example, about 105 to 115 ° on a plane orthogonal to the transition direction of the mark 84, Light 94 including reflected light 109 and fluorescence 86 emitted from the irradiation position of the irradiation light 85 on the surface of the mark 84 is taken in as incident light. The captured light 94 is converted into a voltage as illustrated in FIG. 47B proportional to the intensity of incident light by the light receiving element 106 and amplified to a predetermined voltage value by the AC amplifier circuit 105. The signal S5 is input to the mark detection unit 96, and a signal corresponding to the mark position is taken out.

    The mark detection unit 96 outputs a mark signal S4 as shown in FIG. 47C corresponding to the mark formation position, a comparison value setting circuit 111 for setting a comparison value Vc in the comparison circuit 110, a mark 84 includes a data part determination circuit 112 for determining the data part 89 in 84.

    The comparison value setting circuit 111 detects a portion corresponding to the introduction portion 91 of the mark 84 in the electric signal S5 sent from the photoelectric conversion portion 95, determines the comparison value Vc in proportion to the level in the introduction portion 91, and compares it. Input to the circuit 110. At the same time, a predetermined signal S6 is sent to the data portion determination circuit 112 to notify that the detection of the data portion 89 has started.

    The data part determination circuit 112 notifies the comparison circuit 110 of the comparison time of the comparison value Vc and the input signal S5, and detects the start of scanning of the data part 89 by the start signal S6 sent from the comparison value setting circuit 40. On the other hand, the end of the data portion 89 is detected by the signal S4 output from the comparison circuit 110, and the signal S7 is input to the comparison circuit 110.

    The comparison circuit 110 outputs a rectangular wave signal S4 as shown in FIG. 47C in response to the time when the level of the signal S5 sent from the photoelectric conversion unit 95 falls below the set value Vc. S4 is sequentially sent to the data processor 97, and the contents of the data part 89 of the mark 84 are analyzed by measuring the pulse width and pulse interval of the signal S4.

    Next, the operation of the mark detection unit 96 will be described with reference to the flowchart of FIG. First, when the operation is started in step 120, initial setting is performed in step 121, and a comparison value setting process starting from step 122 is started.

    In the comparison value setting step, the timing at which the signal level suddenly rises is constantly monitored at step 122 by differentiating the input signal S5 sent from the photoelectric conversion unit 95, for example. If a rising edge is detected at time t1 in FIG. 47, a timer is started in step 123 to start timing, and in step 124 it is waited for a falling edge of the input signal to be detected.

    When the falling of the signal level is recognized, the elapsed time of the timer is further checked in step 125. At this time, if it is determined that the elapsed time is less than the preset time, it is determined that unnecessary signal input such as noise is input, and the process returns to the previous stage of step 122.

  However, when the set time elapses in step 125 when the signal level detected at time t2 falls, for example, a voltage obtained by dividing the average value Vm of the signal level from the rising to the falling at a preset ratio. The value is determined as the comparison value Vc in step 126 and input to the comparison circuit 110. At the same time, in step 127, a signal S7 is sent to the comparison circuit 110 via the data portion determination circuit 112 to instruct the start of the comparison operation.

    In the comparison circuit 110, in the comparison processing step of step 128, the “H” level signal corresponding to the period when the level of the input signal S5 is lower than the set value Vc, and the “L” level signal corresponding to the period higher than the set value Vc. Are outputted, a rectangular wave mark signal S4 corresponding to a portion where the phosphor layer as the original data is not formed is outputted.

    This mark signal S4 is detected at the same time in step 129 at the “L” level, and if it is determined that the time exceeds a preset time, the other introduction of the mark signal S4 is passed. The comparison circuit 110 is notified that the unit 91a has been entered, and the comparison processing step is terminated.

    It should be noted that, instead of inverting the entire conventional code mark as shown in FIG. 45A, the inverted data portion 89 as shown in FIG. 45B or not inverted as shown in FIG. 45C. The front and back of the data part 89a may be sandwiched between the introduction parts 91 and 91a. If the scanning direction of the mark 84 is constant, it is sufficient to provide only one introduction portion 91 corresponding to the scanning start position. Further, the shape of the introducing portion 91 is not limited to a rectangular shape, and can be arbitrarily changed as long as it can be distinguished from the data portion 89.

    Further, instead of sequentially processing the signal S5 sent from the photoelectric conversion unit 95 as described above, the mark detection unit 96 temporarily stores a series of input waveform changes while sampling the data. It is also possible to detect the formation position of the mark 84 using the above procedure or a similar procedure.

    Furthermore, not only when the irradiation light 85 is continuously irradiated and the fluorescence 86 is detected as described above, the afterglow of the fluorescence 86 is detected by intermittently irradiating the irradiation light 85, and the formation position of the mark 84 is determined. It can also be used for determination, and the detection method of the fluorescence 86 is not limited.

    Furthermore, instead of fixing the optical reader side and moving the mark 84, for example, a portable probe shape in which the light irradiation unit 93 and the photoelectric conversion unit 95 are integrated, and the mark 84 side is fixed and optically connected. The reader side may be shifted manually or automatically. Further, the irradiation light 85 may be scanned at a predetermined angle, and the light emitted from the scanning position may be detected by the detector 104. The same applies to other optical reading apparatuses.

(Example 6 of optical reader)
Next, a sixth embodiment of the optical reading device will be described. Since the configuration of the card 80 and the mark 84 used in this embodiment is the same as that of the fifth embodiment, description thereof will be omitted.

    As shown in FIG. 49, the optical reader according to this embodiment includes a light irradiating means 151 for intermittently irradiating the mark 16 with light 85 having a substantially constant intensity at a predetermined period. The photoelectric conversion means 153 that takes in the incident light 94 emitted from the irradiation position of the light 85 and converts it into an electrical signal, and the lowest corresponding to the irradiation timing of the irradiation light 85 in the light irradiation means 151 and immediately before the start of irradiation. Waveform detection means 154 capable of individually detecting a value, a maximum value corresponding to immediately before irradiation stop, and a detection value 157 immediately after irradiation stop, a comparison value 158 obtained by dividing the difference between the maximum value and the minimum value, and A mark determination unit 155 is provided that determines the formation position of the mark 84 when the detection value 157 exceeds the comparison value 158 by comparing with the detection value 157.

    Further, an optical filtering means 152 for selectively taking in the light component having the same wavelength as that of the fluorescence 86 from the incident light 94 is provided on the input side of the photoelectric conversion means 153, and the waveform detecting means 154 has an input waveform of a predetermined timing. A signal input determination unit 156 is provided that samples a value, maintains the value until the next sampling, and determines whether the highest value output from the waveform detection unit 154 is a significant value. The mark determination means 155 is configured to perform the comparison operation only during the period when the signal input determination means 156 determines the highest value as a significant value.

    More specifically, as shown in FIG. 50, the optical reading apparatus has a traveling unit 92, a light irradiation unit 93, a photoelectric conversion unit 94, a mark detection unit 95, and a data processing unit 36. And a signal generator 130 for generating various control signals.

    The signal generation unit 130 generates at least a drive signal S8 used in the light irradiation unit 93 and three types of timing signals S9, S10, and S11 used in the mark detection unit 96. The signal generation unit 130 includes a clock signal S12 generation circuit 131 and The control signal generating circuit 132 generates various control signals from the clock signal S12.

    As shown in FIG. 52A, the clock signal generation circuit 131 continuously generates a pulsed clock signal S12 at a constant time interval of about 100 μsec, for example. In the control signal generation circuit 132, by switching the signal level every time five clock signals S12 are input, a rectangular wave shape whose level changes at a time interval of about 500 μsec as shown in FIG. A drive signal S8 is formed. Further, the control signal generation circuit 132 outputs a pulse signal in conjunction with the input of the fourth, sixth and ninth clock signals S12, for example, from the rising edge of the drive signal S8, so that FIG. Three types of timing signals S9 to S11 synchronized with the drive signal S8 as shown in (e) are formed.

    The mark detection unit 96 includes a sample-and-hold circuit 133 that measures the change in the signal S13 from the photoelectric conversion unit 95 shown in FIG. 52 (f), the first to third comparison circuits 134, 135, and 136, and the first and first comparison circuits. 2 display circuits 137 and 138.

    As shown in FIG. 50, the sample hold circuit 133 is connected to the input side of the voltage buffer circuit 139 using the OP amplifier, the capacitor 140 for holding the input voltage value, and the timing signals S9 to S11 sent from the signal generator 130. One set of sampling circuits 142 including analog switches 141 that are turned on at the input is provided for three sets.

    The sample hold circuit 133 generates a series of voltage change signals S13 corresponding to the intensity of the incident light 94 as illustrated in FIG. 52 (f) sent from the photoelectric conversion unit 95 individually and periodically at a plurality of times. And each detected value is held until the next sampling.

    In this embodiment, the timing signal S9 shown in FIG. 52C is applied to the first sampling circuit 142a (see FIG. 51), and the voltage value immediately before stopping the irradiation of the light 85 is indicated by the thick line in FIG. The maximum value Vm of the incident light 94 shown is detected. Also, the timing signal S10 shown in FIG. 52D is applied to the second sampling circuit 142b, and the intensity of the afterglow shown by the broken line in FIG. Detect as.

    Further, the timing signal S11 shown in FIG. 52 (e) is applied to the third sampling circuit 142c, and the minimum value of the incident light 94 shown by the thin line in FIG. 52 (g) by the voltage value Vl immediately before the irradiation of the light 85 is restarted. Are detected individually. In this way, the change in the waveform of the incident light 94 is obtained as the change in the voltage value, so that the proportion of the afterglow intensity in the whole can be determined.

    An OP amplifier is used for the first comparison circuit 134 for determining the value of each detection value, and the afterglow voltage value Vd extracted from the second sampling circuit 142b is directly input as a detection value to the negative input terminal thereof. To do. On the other hand, by dividing the difference between the voltage values extracted from the first and third sampling circuits 142a and 142c by the variable resistor 143, the voltage value Vc is input as a comparison value indicated by a one-dot chain line in FIG. When the detection value Vd exceeds the comparison value Vc, a predetermined signal S14 is output to the third comparison circuit 136.

    Here, the second comparison circuit 134 compares the maximum value Vm output from the first sampling circuit 142a with a predetermined set value, and outputs a predetermined signal S15 during a period when the maximum value Vm is below the set value. When the maximum value Vm exceeds the set value, the output of the signal S15 is stopped, and its output terminal is connected in parallel to the output side of the first comparison circuit 134 via the diode 144 connected in the forward direction. A signal is input to the three comparison circuit 136.

    The third comparison circuit 136 applies the output from the first comparison circuit 134 and the second comparison circuit 135 to the negative side input terminal of the OP amplifier and compares it with the set value, and switches the switching element 145 by the FET provided on the output side. Regulate on and off. During the period when the output voltages from the first and second comparison circuits 134 and 135 are both lower than the set value, the “1” signal corresponding to the detection of the mark 84 is output to the data processing unit 97, but at least one of them is output. When there is an “H” level signal output from the comparison circuits 134, 135, the signal S 16 sent to the data processing unit 97 becomes “0” indicating that the mark 84 is not detected.

    Accordingly, during the period in which the output signal S14 from the first comparison circuit 134 is indefinite because the intensity of the incident light 94 is low, the signal S15 of “H” level from the second comparison circuit 135 is the minus value of the third comparison circuit 136. As a result of being applied to the side input terminal, the output of the third comparison circuit 136 is forcibly set to “0” to inform the data processing unit 97 that the mark 84 has not been detected.

    On the other hand, in a state where the intensity of the incident light 94 is equal to or higher than a certain value and the mark detection is normally performed, the output from the second comparison circuit 135 is lowered to the “L” level, and thus the output from the first comparison circuit 134. The third comparison circuit 136 operates in response to the level change, that is, the detection of the fluorescence component, and the presence or absence of mark detection is determined as shown in FIG.

    The determination possible time by the third comparison circuit 136 is displayed by causing the LED 146 of the first display circuit 137 provided on the output side of the second comparison circuit 135 to emit light. Further, regarding the detection time of the mark 84, the LED 147 of the second display circuit 138 provided on the output side of the third comparison circuit 136 is caused to emit light.

    The capacitor 140 and the resistor 148 provided on the input side of the sample hold circuit 133 and the capacitor 149 and the resistor 150 provided on the input side of the third comparison circuit 136 constitute an integrating circuit, and input of pulse noise This prevents the input level from rising instantaneously and malfunctioning.

    Further, the cycle of the drive signal S8 in this embodiment is about 1 msec, which is set to about twice the afterglow time of the phosphor constituting the mark 84, but the value of both the cycle and the afterglow time can be appropriately changed.

    Further, the transmission time timing of the sample signals S9 to S11 is also set closer to the blinking timing of the irradiation light 85 corresponding to the light emission characteristics of the fluorescence 86, so that the fluorescence 86 and the reflected light 109 can be more accurately separated. . In this case, the value of the fluorescence 86 can be detected from the voltage values immediately after the start of light irradiation and immediately before the irradiation stop without detecting afterglow.

    Further, the comparison operation of each detection value may be a digital type using a microprocessor instead of the analog type using an OP amplifier as described above. In this case, instead of or in addition to selectively sampling the voltage value in the characteristic portion of the input waveform, the entire shape of the waveform can be detected and the change can be obtained by digital processing.

(Example 7 of optical reader)
Next, Example 7 of the optical reading device will be described. Also in this embodiment, the configuration of the card 80 and the mark 84 is the same as that in the fifth embodiment, so that the description thereof is omitted.

    As shown in the schematic configuration of FIG. 53, the optical reader according to this embodiment includes a light irradiation means 160 that emits light 85 while being intermittently interrupted at substantially constant time intervals, and a light irradiation position. The photoelectric conversion means 162 that receives the incident light 94 emitted from the light and converts it into an electrical signal, the optical filtering means 161 that selectively takes in the fluorescence 86 from the incident light 94, and the light of the light irradiation means 160 A waveform shaping unit 163 that inverts and amplifies half of the output signal from the photoelectric conversion unit 162 while synchronizing with the 85 irradiation period at a timing that is 90 degrees out of phase, and a DC component from the output signal of the waveform shaping unit 163 The low-pass filtering means 164 for selectively extracting the detection signal, the detection voltage output from the filtering means 164 is compared with the comparison voltage, and when the detection voltage exceeds the comparison voltage, a predetermined mark signal is output. And a comparison means 165 for outputting.

    The optical reading apparatus will be described in detail. As shown in FIG. 54, the optical reading device is emitted from the traveling portion 166 of the card 80, the light irradiation portion 167 for the mark 84 on the card 80, and the position on the mark 84 irradiated with the light 85. A photoelectric conversion unit 168 for converting the light 94 to be converted into an electric signal, a mark detection unit 169 for outputting a mark signal S28 corresponding to the formation position of the mark 84 from the converted electric signal, and a card from the detected mark signal S28 80 is constituted by a data processing unit 170 for determining the data content on 80.

    The card running unit 166 moves horizontally at a constant speed of about 200 to 400 mm per second, for example, while supporting both side edges of the card 80 by rollers 172 that are rotationally driven by a motor drive circuit 171 corresponding to the insertion time of the card 80. By doing so, the barcode-shaped mark 84 formed with a phosphor on the upper surface side of the card 80 passes below the light irradiation unit 167 and the photoelectric conversion unit 168. Data relating to the operation timing of the motor drive circuit 171 is sent to the data processing unit 170 to inform the data processing necessary time for determining the mark contents.

    The light irradiation unit 167 individually generates an oscillation circuit 173 that generates a clock signal S20 illustrated in FIG. 56A, and a drive signal S21 and two types of control signals S22 and S23 in synchronization with the clock signal S20. A signal generation circuit 174 to be formed, a light source drive circuit 175 that amplifies the drive signal S21, and a light source 176 that generates light 85 by the light source drive circuit 175.

    As shown in FIG. 56A, the oscillation circuit 173 continuously generates a pulsed clock signal S20 at a constant time interval of about 250 μsec, for example.

    As shown in FIG. 55, the signal generation circuit 174 includes two D-type flip-flops 177 and 178, and both clock signal input terminals 179 and 180 are connected in parallel with the output terminal of the oscillation circuit 173. Between the data input terminal 181 of the first flip-flop 177 and the inverting output terminal 182 of the second flip-flop 178, the non-inverting output terminal 42 of the first flip-flop 177 and the data input terminal 184 of the second flip-flop 178 are mutually connected. Directly connected.

    With this configuration, the non-inverted output terminal 183 of the first flip-flop 177 outputs a rectangular-wave drive signal S21 whose output level is inverted at a time interval of about 500 μsec every time two clock signals S20 are input. Is done. Further, the first control signal S22 having the same frequency as the drive signal S21 and the phase delayed by 90 degrees from the non-inverted output terminal 184 of the second flip-flop 178, and the same frequency and phase as the drive signal S21 from the inverted output terminal 182. Are respectively output by the second control signal S23 advanced by 90 degrees.

    The light emission source drive circuit 175 is a transistor switch 45 that is turned on in conjunction with the input of the drive signal S21. The Zener diode 186 is connected between the emitter and base to limit the base voltage, while the light emitting element is connected in series with the collector. 187 is connected.

    The light emission source 176 is obtained by attaching a glass fiber light guide to a light emitting portion of a light emitting element 187 such as a light emitting diode that generates near infrared light having a light emission center wavelength of about 800 nm. The front end of the light guide is brought close to the surface of the card 80 to a distance of 2 mm or less, and the entire light guide is 45 ° to 60 ° on the surface orthogonal to the transition direction of the mark 84 and from the horizontal direction. (See FIG. 44).

    The photoelectric conversion unit 168 includes a detector 188 that converts incident light into a change in current, and an AC amplification circuit 189 that converts the current into a voltage and then amplifies it to a predetermined magnitude.

    The detector 188 is connected to the light source 176 side through an optical filter that selectively passes the fluorescence 86 generated from the mark 84 on the light receiving surface of a light receiving element such as a photodiode or photocell having light receiving sensitivity in the infrared region. A light guide that is substantially the same as that is fixed.

    By making the tip of the light guide on the detector 188 side adjacent to the tip of the light guide on the light source 176 side and providing an inclination angle of, for example, about 105 to 115 ° on a plane orthogonal to the transition direction of the mark 84, The light 94 emitted from the irradiation position of the irradiation light 85 on the surface of the mark 84 is captured. The captured light 94 is attenuated as much as possible by reflected light 109 other than the wavelength component of fluorescence 86 and external light 190 (see FIG. 53) by an optical filter, and then is proportional to the intensity of incident light by the light receiving element. Converted to current.

    Further, after being amplified to a predetermined voltage value by the AC amplifier circuit 189, it is input to the mark detection unit 169 as a detection signal S24 illustrated in FIG. 56 (e), and a signal S28 corresponding to the mark formation position is selected and extracted. .

    This embodiment is characterized by the configuration of the mark detection unit 169. As shown in FIGS. 54 and 55, the first and second control signals S22 and S23 are used to generate the detection signal S24 in FIG. 56 (f). A synchronous rectifier circuit 191 that shapes the signal S25 to be illustrated, a low-pass filter circuit 192 that outputs a signal S26 that increases or decreases in response to detection of the fluorescence 86 by removing an AC component from the signal S25, When the input of the signal S26 is determined, the comparator 193 outputs a mark signal S28.

    The synchronous rectifier circuit 191 connects the two input terminals 196 and 197 in the differential amplifier circuit 195 using the OP amplifier 194 in parallel, inputs the detection signal S24, and analogs the input terminals 196 and 197 in series. The switches 198 and 199 are inserted, and the analog switches 198 and 199 are individually controlled on and off using the control signals S22 and S23.

    That is, the analog switch 198 connected to the plus side input terminal 196 of the OP amplifier 194 is turned on corresponding to the “H” level period in the first control signal S22, while the analog switch connected to the minus side input terminal 197. 199 is turned on corresponding to the period of “H” level in the second control signal S23.

    Here, the “H” level period in the first control signal S22 is a period delayed by 90 degrees from the irradiation period of the light 85 by the light emitting element, whereas the “H” level period in the second control signal S23. Is a period in which the phase is advanced by 90 degrees. Therefore, in the detection signal S24 input to the synchronous rectifier circuit 191, the second half of the period of light irradiation and the first half of the period when the light irradiation is stopped are stopped at the positive input terminal 196 via the analog switch 198. The latter half period and the first half period irradiated with light are separately input to the negative input end 197.

  As a result, from the output side of the synchronous rectifier circuit 191, as shown in FIG. 56 (f), the input period of the detection signal S 24 to the positive input terminal 196 is non-inverted and amplified as a change in positive voltage, resulting in a negative input terminal. During the input period to 197, the signal S25 is extracted as a negative voltage change by being inverted and amplified.

    By the way, the change in the detection signal S24 is only the reflected light 109 from the mark 84 and its card 80 in the period when the light 85 is not irradiated on the mark 84, and is indicated by a one-dot chain line in FIG. It becomes a rectangular wave shape. Therefore, the output signal from the synchronous rectifier circuit 191 is also inverted in the first half of the reflected light component and non-inverted in the second half as shown by the shaded portion in FIG. 56 (f), and the values on the plus side and the minus side are equal. Extracted as a signal.

    On the other hand, when the irradiation light 85 scans the mark 84, due to the persistence of the fluorescence 86, as shown by the solid line in FIG. 56 (e), the fluorescence component increases exponentially from the time of light irradiation. The fluorescence component decreases exponentially from when the light irradiation is stopped. Accordingly, the output signal S25 from the synchronous rectifier circuit 191 is selectively non-inverted and amplified during the period when the fluorescent component is large, and inverted and amplified during the small period, so that the signal on the plus side is extracted as a signal sufficiently larger than the minus side. .

    Therefore, in this embodiment, the output signal S25 from the synchronous rectifier circuit 191 is further removed through the low-pass filter circuit 192 to extract only the DC component. That is, when the mark 84 is not scanned as indicated by the alternate long and short dash line in FIGS. 56 (e) and 56 (f), the plus side and the minus side are equal, so both are canceled and the filtering circuit 192 There is no output.

    However, while scanning the mark 84 indicated by the solid line in FIG. 56 (e), the external light 190 and the reflected light 109 are canceled, but the fluorescence 94 is overwhelmingly larger on the plus side. Therefore, the signal S26 is extracted from the filtering circuit 192 as a positive DC voltage.

    This signal S26 is further input to the comparison circuit 193 using the OP amplifier 200, and the magnitude thereof is compared with the comparison voltage S27 obtained by dividing the voltage stabilized by the constant voltage diode 201 by the variable resistor 202, and the comparison voltage is compared. When a significant signal S26 exceeding S27 is input, the output voltage is set to the “H” level state, and a mark signal S28 for specifying the detection of the mark position is output.

    In this embodiment, the period of the drive signal S21 is about 1 msec, which is set to about twice the afterglow time of the phosphor constituting the mark 84. However, both the period and the afterglow time are appropriately changed. You can also.

(Embodiment 8 of optical reader)
Prior to describing the optical reading apparatus according to the eighth embodiment, an example of a mark will be described with reference to FIG. As shown in the figure, the barcode-like mark 210 is formed by printing on a work 211 such as a card, for example, and its surface is covered with a protective sheet 213 via an adhesive layer 212.

The mark 210 is formed with a transparent ink in which phosphor fine particles excited by, for example, infrared irradiation are dispersed and held in a transparent binder. Examples of the fluorescent fine particles include organic compounds such as dye names Rhodamine 6G, thioflavine, and eosin, or inorganic compounds such as NdP ₅ O ₁₄ , LiNdP ₄ O ₁₂ , and Al ₃ Nd (BO ₃ ) ₄ .

    As the binder, for example, wax, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, polyester, polyurethane, carbonate, and a mixture thereof are used. In addition, an appropriate amount of a plasticizer or a surfactant is added as necessary.

    As a print forming method, a method in which an ink ribbon formed by uniformly applying a transparent ink on a base ribbon is mounted on a thermal head and thermally transferred to the surface of the article, or a method in which a liquid transparent ink is screen printed on the surface of the article Etc.

    As an adhesive for forming the adhesive layer 212, for example, a non-solvent adhesive such as a hot melt adhesive is used in order to prevent deformation of the mark 210 due to swelling or dissolution. As the hot melt adhesive, various types such as an ethylene-vinyl acetate copolymer system, a polyethylene system, a polyamide system, and a polyester system can be used.

    As the protective sheet 213, for example, a transparent resin sheet such as vinyl chloride or polyester is used. A white layer may be formed on the base of the mark 210 in order to increase the light reflectivity and increase the signal level of the signal detected from the mark 210.

    As shown in the figure, when an infrared ray 214 having a center wavelength that matches the excitation wavelength of the phosphor to be used is irradiated toward the mark 210, the phosphor fine particles are excited by receiving the infrared ray 214, and the center wavelength of the infrared ray 214 is Emits fluorescence 215 of different specific wavelengths. If this fluorescent light 215 is received by a light receiver and converted into an electrical signal and binarized, a binarized signal corresponding to the barcode pattern of the mark 210 is obtained, and information held by the mark 210 is read. be able to.

    58 is a configuration diagram of an optical reading apparatus according to the embodiment. As shown in FIG. 58, the optical reading apparatus includes a light projecting unit 216, a light receiving unit 217, an optical filter 218, an amplifying unit 219, and an amplifying unit 219. A first amplification factor setting unit 220 that maximizes the amplification factor, a second amplification factor setting unit 221 that neutralizes the amplification factor, a third amplification factor setting unit 222 that minimizes the amplification factor, A signal detection unit 223 and a clock signal generator 224 that supplies a drive clock to the signal detection unit 223 are provided.

    The signal detection unit 223 includes an A / D conversion unit 225 that converts the analog reproduction signal a into a digital signal, a CPU 226 that analyzes a barcode signal from the binarized signal obtained by the A / D conversion unit 225, and a program The memory device 227 includes a memory and a working memory, and an I / O port 228 that controls input / output.

    A preferable amplification factor is determined from the state of the analog reproduction signal a captured by the A / D conversion unit 225, and a signal for selecting one of the amplification factor setting units 220, 221, and 222 is selected based on a command from the CPU 226. Output from / O port 228. Further, the signal detection unit 223 reproduces the barcode signal from the analog reproduction signal a based on the program stored in the memory device 227 and outputs it from the I / O port 228.

    As shown in FIG. 59, the optical reading device 229 is disposed so as to face the passage path 230 of the workpiece 21. A reflector 231 is disposed in a portion facing the light projecting unit 216 and the light receiving unit 217 mounted on the optical reading device 229 via the passage path 230. The light projecting unit 216, the light receiving unit 217, and the reflector 231 are configured such that the infrared light projected from the light projecting unit 216 is reflected by the reflector 231, and the reflected light is incident on the light receiving unit 217. The output signal level is adjusted to a saturation level.

    Next, a mark reading procedure in this apparatus will be described with reference to FIGS.

    When the apparatus is activated, the first amplification factor setting unit 220 is selected based on a command from the CPU 226, and the initial amplification factor of the amplification unit 219 is set (240). Waiting to pass.

In the stage of waiting for the workpiece 211 to pass, that is, the irradiation of infrared rays from the light projecting unit 216 is started, but at the stage where the workpiece 211 is not present between the light projecting unit 216 and the light receiving unit 217 and the reflector 231, light projection is performed. Since the infrared rays emitted from the unit 216 are reflected by the reflector 231 and the reflected light enters the light receiving unit 217, the analog reproduction signal a becomes the saturation level V _ref as in the area A of FIG. 61 (a). .

    When the workpiece 211 passes between the light projecting unit 216 and the light receiving unit 217 and the reflector 231, first, infrared light is irradiated to a portion of the workpiece 211 where the mark 210 is not printed (so-called ground), and the reflected light is received. The light is received by the unit 217. In general, the reflectance of the work 211 is lower than the reflectance of the reflector 231. Therefore, the level of the analog reproduction signal a is lowered as in the region B of FIG.

At this stage, the processing by the CPU 226 shifts to 242 and determines the level of the analog reproduction signal a. When it is determined that the level of the analog reproduction signal a in the background portion is equal to or higher than the gain switching determination level V _th [when corresponding to the background (1), (2) in FIG. The second amplification factor setting unit 221 is selected by the command, and the amplification factor of the amplification unit 219 is lowered to a middle level (243). As a result, the level of the analog reproduction signal a for the backgrounds (1) and (2) falls below the gain switching determination level V _th as shown by the broken line in FIG.

When it is determined at 242 that the level of the analog reproduction signal a in the background portion is equal to or lower than the gain switching determination level V _th [when corresponding to the background (3), (4) in FIG. 61], and at 243, the amplification unit 219 After the gain is reduced, the process proceeds to 244 and waits for the arrival of the mark 210. When the mark 210 arrives and is irradiated with infrared rays, the phosphor in the mark 210 is excited and emits fluorescence, so that the level of the analog reproduction signal a rises.

At this stage, the processing by the CPU 226 shifts to 245, and the level of the analog reproduction signal a is determined. When the peak value of the analog reproduction signal a in the barcode portion of the mark 210 is determined to be equal to or higher than the gain switching determination level V _th (when corresponding to the background (1), (2) in FIG. 61B) In response to a command from the CPU 226, the third amplification factor setting unit 222 is selected, and the amplification factor of the amplification unit 219 decreases to the lowest value (246). As a result, the peak values of the analog reproduction signals a of the backgrounds (1) and (2) are lowered to the gain switching determination level V _th or lower as shown by the broken line in FIG.

If it is determined at 245 that the peak value of the analog reproduction signal a in the barcode portion is equal to or lower than the gain switching determination level V _th (when corresponding to the backgrounds (4) and (4) in FIG. 61A), And 246, after the amplification factor of the amplification unit 219 is lowered, the process proceeds to 247 and binarization is performed up to the final bar of the mark 210.

    62 shows an output signal waveform of the light receiving unit 217, an analog reproduction signal waveform output from the amplification unit 219, and a binary signal output from the signal detection unit 223. 4A is a waveform diagram of an output signal from the light receiving unit 217, FIG. 4C is a binarized signal diagram output from the signal detection unit 223, and FIG. 4B is a diagram illustrating the first amplification factor setting unit 220. When the second amplification factor setting unit 221 is selected, the analog reproduction signal waveform diagram when the second amplification factor setting unit 221 is selected, and (b ″) is the third amplification signal waveform diagram when the analog reproduction signal waveform is selected. It is a figure which shows an analog reproduction signal waveform when the rate setting part 222 is selected.

As is apparent from FIG. 62, when the amplification factor of the amplification unit 219 is appropriately switched in accordance with the level and amplitude of the analog reproduction signal and the level and amplitude of the analog reproduction signal are set to a predetermined value, a predetermined specific level is set. it is possible to obtain a binary signal by slicing the analog reproduction signal at a slice signal V _T.

The optical reading apparatus of the present embodiment switches the amplification factor of the amplifier 219 in three stages according to the level and amplitude of the analog reproduction signal a, and the analog reproduction signal a always matches the slice signal V _T of a specific level set in advance. As a result, the reading of the signal from the mark is not inaccurate or impossible due to the difference in the physical properties of the work 211, and the versatility and reliability are excellent. Further, since the analog reproduction signal a is sliced by one slice signal V _T to obtain a binary signal, the configuration of the signal detection unit 223 can be simplified.

    In this embodiment, the amplification factor of the amplifier 219 is switched to three levels according to the level and amplitude of the analog reproduction signal a, that is, the reflected light component from the work 211 and the fluorescence from the mark 210. It is also possible to switch to multiple stages. Furthermore, the amplification factor of the amplifier 219 can be changed steplessly by using, for example, an electronic volume as the amplification factor setting unit.

    In this embodiment, the amplification factor of the amplifier 219 is switched according to the reflected light component from the workpiece 211 of the analog reproduction signal a and the fluorescence from the mark 210. However, the amplification factor of the amplifier 219 is changed according to only the reflected light component from the workpiece 211. The amplification factor can also be switched.

(Example 9 of optical reader)
In the above-described embodiment, the reflector 231 is disposed opposite to the light projecting unit 216 and the light receiving unit 217. However, instead of the reflector 231, as illustrated in FIG. 63, an absorber that absorbs light emitted from the light projecting unit 216. 249 can also be arranged.

In this case, since the infrared rays irradiated from the light projecting unit 216 are absorbed by the absorber 249 and almost no light is incident on the light receiving unit 217 at the stage of waiting for the workpiece 211 to pass, as shown in the area A in FIG. The analog reproduction signal a is almost at the ground level A _GND .

    When the workpiece 211 passes between the light projecting unit 216 and the absorber 249, the reflected light from the workpiece 211 is incident on the light receiving unit 217, so that the analog reproduction signal a rises as shown in the area B in FIG. To do.

Furthermore, when the mark 210 arrives and the infrared ray is irradiated to the mark 210, the fluorescence from the phosphor constituting the mark 210 is incident on the light receiving unit 217, so that the region C in FIG. The analog reproduction signal a further rises. Accordingly, it is determined whether or not the analog reproduction signal level in the B region exceeds a preset gain switching determination level V _th, and if it exceeds, the amplification factor of the amplifying unit 219 is decreased to reduce the gain of the eighth embodiment. The same signal reproduction can be performed.

(Example 10 of optical reader)
FIG. 65 shows the configuration of the amplification unit and the signal detection unit of the optical reader according to the tenth embodiment. As shown in the figure, the optical reading apparatus of this embodiment includes a first differential amplifier 251 including a first operational amplifier 250 and first to third resistors R ₁ , R ₂ , R ₃ , A second differential amplifier 253 composed of two operational amplifiers 252 and fourth to sixth resistors R ₄ , R ₅ , R ₆ , a first comparator 254 connected to the first operational amplifier 251, and The first variable resistor VR ₁ for setting the slice level of the first comparator 254, the second comparator 255 connected to the second operational amplifier 253, and the second level for setting the slice level of the second comparator 255. a variable resistor VR ₂ of 2, the output signal f of the first comparator 254 as a trigger, a one-shot multivibrator 256 which generates a pulse of a predetermined width for each trigger, the one-shot multi An inverter 257 that inverts the output signal of the vibrator 256, an AND gate 258 that takes the logical product of the output signal g of the second comparator 255 and the output signal h of the inverter 257, and an output signal i of the AND gate 258 An OR gate 259 for taking a logical sum with the output signal f of the first comparator 254 is provided.

    In this embodiment, the amplification factor of the first differential amplifier 251 is low, the amplification factor of the second differential amplifier 253 is adjusted high, and the slice level of the first comparator 254 and the slice of the second comparator 255 are adjusted. The level is set to the same value. In addition, the pulse width of the pulse output from the one-shot multivibrator 256 is the same as the time required when the portion having the shortest gap between the bars constituting the mark (barcode) is scanned by light projection. Has been adjusted.

Next, the operation of this optical reader will be described.
FIG. 66 shows the first analog reproduction signal a ₁ output from the first differential amplifier 251. A in the figure shows a signal when the reflected light level from the work (ground) is low and the fluorescence level from the mark is high, and B shows a low reflection light level from the work and a fluorescence level from the mark. , C indicates a signal when the reflected light level from the workpiece is large and the fluorescence level from the mark is small. When the first analog reproduction signal a ₁ is binarized by the first comparator 254, the binarized signal f shown in FIG. 68A is obtained.

FIG. 67 shows the second analog reproduction signal a ₂ output from the second differential amplifier 253. 66 corresponds to A in FIG. 66, B ′ corresponds to B in FIG. 66, and C ′ corresponds to C in FIG. When the second analog reproduction signal a ₂ is binarized by the second comparator 255, a binarized signal g shown in FIG. 68B is obtained.

    The output signal h of the inverter 257 scans the portion where the pulse width of the pulse output from the one-shot multivibrator 256 is the shortest gap between each bar constituting the mark (barcode) by light projection. 68 (c) because the time is adjusted to be the same as the time required.

    Accordingly, when the AND signal of the output signal g of the second comparator 255 and the output signal h of the inverter 257 is taken by the AND gate 258, the output signal i becomes as shown in FIG. When the OR of the output signal i of the AND gate 258 and the output signal f of the first comparator 254 is taken by the OR gate 259, the output signal j becomes as shown in FIG. Is detected.

    In this embodiment, a first binarized signal f corresponding to a high level detection signal and a second binarized signal g corresponding to a low level detection signal are separately generated, and the logic of these signals is generated. Since the binarized signal corresponding to the entire analog reproduction signal is obtained by taking the product and logical sum, the level of the detection signal detected from a series of marks formed on one workpiece is partially changed. Even if it is accompanied by, accurate information can be read reliably.

    In the present embodiment, the slice levels of the two comparators 254 and 255 are fixed, but the slice levels can be set to different values as required.

(Example 11 of optical reader)
In this embodiment, in the optical reading apparatus shown in FIG. 65, the amplification factors of the two differential amplifiers 251 and 253 are set to be the same, and the slice levels of the two comparators 254 and 255 are set to different values. .

In the case of the present embodiment, as shown in FIG. 69, the analog reproduction signal a output from the first differential amplifier 251 and the second differential amplifier 253 becomes the same level, and the analog reproduction signal a is the first level. The first slice signal S ₁ set in the second comparator 254 and the second slice signal S ₂ set in the second comparator 255 are sliced.

The first slice signal S ₁ slices the high level portions A and C of the analog reproduction signal a to generate a binary signal f corresponding to FIG. On the other hand, the second slice signal S ₂ slices the low level portion B of the analog reproduction signal a, and generates a binary signal g corresponding to FIG. Therefore, by taking the OR of the output signal f of the first comparator 254 and the output signal g of the second comparator 255 by the OR gate 258, the output signal j of FIG. 68 (e) can be obtained. The mark information can be reliably read from the detection signal accompanied by the level fluctuation.

    In the above embodiment, the case where two differential amplifiers and two comparators are provided has been described. However, the number of differential amplifiers and comparators can be increased. If the number of differential amplifiers and comparators is increased, accurate information can be read from more complicated detection signals or analog reproduction signals.

    In addition to the above, the optical reading system of the present invention has the following uses and characteristics.

1. Factory Automation (FA) Management at the time of assembly of automobiles, that is, management by car type, country of export destination, date of manufacture and manufacturing lot, etc. can be managed without losing appearance by using latent image marks.

  2. For example, even when marking on a black object such as a tire or a transparent object such as glass or synthetic resin, which cannot be read with a conventional reflective barcode, the mark can be read.

  3. Since the latent image mark can be read even if characters or designs are printed on the latent image mark, it is possible to superimpose information, and a narrow space such as a product price tag or a product tag can be used effectively.

  4). 1 above. And 3. For the same reason, it can be effectively applied to products such as cosmetics and medicines that emphasize design, or various cosmetic boxes and packages that require a high-class feel.

  5). The latent image mark can be read even in an environment that cannot be used with a conventional reflective bar code because it is contaminated with oil or dust in a factory or on-site.

  6). 1 above. And 3. For the same reason, the delivery information to the customer (usually, only the information required by the customer in the form and format specified by the customer is entered in the delivery slip) can have the management information of the manufacturer as a hidden code.

  7). It can be used as a game card (barcode game) by putting information as a hidden code in a card-like object.

  8). 1 above. And 3. For the same reason, if used for book management, book management, drawing management, etc., the design is not impaired.

  9. Forgery, alteration, and alteration are extremely difficult, so it can be applied to entrance / exit management, attendance / exit management, hotel key cards, etc.

  10. Forgery, alteration, and alteration of student ID cards and ID cards can be prevented, and miniaturization and space saving are possible.

  11. It is possible to prevent forgery, alteration, and tampering of stamp cards and point cards, and to reduce the size and space.

  12 It can be introduced into a pachinko prize exchange system to prevent counterfeiting, alteration and tampering.

It is an emission spectrum figure of the neodymium cinnamate ytterbium (1/1) compound salt concerning the example of the present invention. It is a characteristic view which shows the relationship between the molar ratio of Nd / Yb in the neodymium cinnamate-ytterbium (1/1) complex salt, and luminescence intensity. It is a characteristic view which shows the irradiation timing of excitation light, and the light emission state of two types of fluorescent substance. It is a figure for demonstrating relationships, such as the length of a slit, the conveyance speed of a latent image formation member, and the space | interval of a printing layer. FIG. 6 is a characteristic diagram showing the relationship between the viscosity of ink for an inkjet printer according to the present invention and the relative output and the variation rate of droplet size. It is a characteristic view showing the relationship between the surface tension of the ink for an ink jet printer in the present invention and the variation rate of the droplet size. FIG. 6 is a characteristic diagram showing the relationship between the specific resistance of ink for an inkjet printer and the variation rate of droplet size in the present invention. It is a characteristic view which shows the relationship between pH of the ink for inkjet printers in this invention, and dispersion stability. It is a figure which shows the kind and ratio of the preparation raw material of the fluorescent substance which concern on samples 1-7. It is a figure which shows the kind and ratio of the preparation material of the fluorescent substance which concern on the samples 8-15. It is a figure which shows the calcination temperature of the fluorescent substance concerning samples 1-7, the composition of fluorescent substance, and particle size. It is a figure which shows the calcination temperature of the fluorescent substance which concerns on samples 8-15, the composition of fluorescent substance, and particle size. It is an emission spectrum figure of the fluorescent substance of the sample 1 which concerns on the Example of this invention. It is an emission spectrum figure of the fluorescent substance of the sample 7 which concerns on the Example of this invention. It is an emission spectrum figure of fluorescent substance of sample 15 concerning a comparative example. It is a figure which shows the kind and ratio of the preparation raw material of the fluorescent substance of the samples 16-20 which concern on the Example of this invention, and a baking condition. An emission spectrum of the phosphor _{(ErY) 3 (FeAl) 5} O 12 of the sample 16 according to an embodiment of the present invention. It is a spectral sensitivity characteristic figure of Ge photodiode. It is a spectral sensitivity characteristic figure of an InGaAs photodiode. It is a figure which shows the kind and ratio of the preparation raw material of the fluorescent substance of the samples 21-25 which concern on the Example of this invention, and a baking condition. Is an absorption emission spectrum of the phosphor Yb _0.3 Y _2.7 Al ₅ O ₁₂ of the sample 21 according to an embodiment of the present invention. Is a graph showing changes in luminous intensity when the value was changed variously the mole fraction of Yb in the phosphor _{Yb X Y 1-X Al 5} O 12 according to Example (X) of the present invention. 6 is an emission spectrum diagram of the phosphor obtained in Example 12. FIG. It is a response waveform diagram with respect to the pulsed light excitation of the phosphor obtained in Example 12. 6 is a photograph of the particle structure of the phosphor obtained in Example 12. It is a characteristic view which shows a time-dependent change of a recovery rate when the fluorescent substance obtained in Example 12 and Comparative Example 9 was immersed in pure water. It is a principle explanatory view for explaining an electric field control method among ink jet recording methods. It is a top view of the mail in which the latent image based on the Example of this invention was formed. It is a top view of the other example of the mail in which the latent image based on the Example of this invention was formed. It is a flowchart for demonstrating the process of provision of the barcode information in a mail, and the reading of the information. It is a schematic block diagram which shows Example 1 of the optical reader of this invention. It is a top view of the mirror used for the reading device. It is a partial cross section for demonstrating the function of the slit member used for the reading device. It is a figure which shows the radiation pattern of the laser beam output from the semiconductor chip used in this Example. It is a figure for demonstrating the positional relationship of the radiation pattern and the printed barcode pattern. It is a figure for demonstrating the relationship between the radiation pattern and the inclined barcode pattern. It is a top view of the reflective mirror used in Example 2 of an optical reader. It is a partial schematic block diagram of the optical reader which uses the reflective mirror. It is a figure for demonstrating Example 3 of an optical reader. It is a figure for demonstrating Example 3 of an optical reader. It is a timing chart which shows the light emission timing of the light emitting element, and the output state of the light receiving element in the detection method using the afterglow of the phosphor. It is a block diagram which shows schematic structure of Example 4 of an optical reader. It is a figure which shows the structure of the semiconductor laser diode used for the optical reader. It is the schematic which shows the basic composition of Example 5 of an optical reader. It is explanatory drawing which shows the formation state of a mark. It is a block diagram which shows the whole structure of the optical reader. It is a figure for demonstrating the detection state of a mark. It is a flowchart of an operation in the mark detection unit. It is the schematic which shows the basic composition of Example 6 of an optical reader. It is a block diagram which shows concretely the whole structure of the optical reader. It is a block diagram which shows the detail of the mark detection part of the optical reader. It is a timing chart of various signals of the optical reading device. It is the schematic which shows the basic composition of Example 7 of an optical reader. It is a block diagram which shows concretely the whole structure of the optical reader. It is a block diagram which shows the detail of the mark detection part of the optical reader. It is a timing chart of various signals of the optical reading device. It is an expanded sectional view which shows the state of the mark formed on a workpiece | work, an adhesive bond layer, and a protection sheet. It is a block diagram which shows Example 8 of an optical reader. It is a figure which shows the arrangement configuration of the optical reader. It is a flowchart which shows the reading procedure of the mark in the optical reader. It is a wave form diagram of the analog reproduction signal in the optical reading device. It is explanatory drawing which shows the relationship between the detection signal in the optical reader, an analog reproduction signal, and a binarization signal. It is a figure which shows the arrangement configuration in Example 9 of an optical reader. It is a wave form diagram of the analog reproduction signal of the optical reader. It is a block diagram of the amplification part and signal detection part in Example 10 of an optical reader. It is a wave form diagram of the 1st analog reproduction signal output from the 1st differential amplifier of the optical reader. It is a wave form diagram of the 2nd analog reproduction signal output from the 2nd differential amplifier of the optical reading device. It is a wave form diagram of the binarization signal output from each part of the optical reader. It is explanatory drawing which shows the signal binarization method in Example 11 of an optical reader. It is explanatory drawing which shows the structure of the conventional optical reader. It is a wave form diagram of the analog reproduction signal in the optical reading device.

Explanation of symbols

10 Latent Image Forming Member 13 Mail 18 Printed Layer 19 Label 22 OCR
23 IJP
24 Barcode Sorting Device 25 Reading Device 26 Semiconductor Laser Drive Device 27 Semiconductor Laser 29 Mirror 30 First Plano-Convex Lens 31 Second Plano-Convex Lens 32 Slit Member 32a Slit 33 Filter 34 Photodiode 35 Through-hole 51 Radiation Pattern 55 Securities 60 Excitation Light 61 Fluorescence 62 Conveying means 63 Long axis 64 Short axis 74 Drive circuit 75 Semiconductor laser diode 77 Light receiving circuit 79 Hold circuit _tu Phosphor rise time t _d Phosphor fall time v Latent image forming member conveyance speed L Print layer Interval

Claims (5)

In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to the emitted excitation light, detecting the fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Photoelectric conversion means for taking light emitted from the irradiation position of the excitation light and converting it into an electrical signal;
Waveform detection means that can synchronize with the irradiation timing of the light irradiation means, individually detect the minimum value corresponding to immediately before the irradiation start, the maximum value corresponding to immediately before the irradiation stop, and the detection value immediately after the irradiation stop,
An optical system comprising: a mark determination unit that compares a comparison value obtained by dividing the difference between the maximum value and the minimum value with the detection value and determines a mark formation position when the detection value exceeds the comparison value. Reader. In Claim 1, provided on the input side of the photoelectric conversion means is a filtering means for selectively capturing light components of the same wavelength as fluorescence from incident light,
The waveform detection means samples the magnitude of the input waveform at a predetermined timing and maintains the value until the next sampling time,
A signal input determining means for determining whether or not the highest value output from the waveform detecting means is a significant value;
An optical reading apparatus characterized in that the determination operation of the mark determination means is possible only during the period when the signal input determination means determines the highest value as a significant value. In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to irradiated excitation light, detecting fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Photoelectric conversion means for inputting light emitted from the irradiation position of the excitation light and converting it into an electrical signal;
Waveform shaping means that inverts and amplifies half of the output signal from the photoelectric conversion means while synchronizing with a timing that is 90 degrees out of phase with the irradiation period of the light irradiation means;
An optical reading apparatus comprising: a low-pass filtering unit that selectively extracts a direct current component from an output signal from the waveform shaping unit. In an optical reading device that detects a mark by irradiating excitation light to a detection mark containing a phosphor that emits light of a different wavelength with respect to irradiated excitation light, detecting fluorescence emitted from the mark,
A light irradiating means for irradiating the excitation light having a substantially constant intensity while being intermittent with a predetermined period;
Filtering means for selectively capturing light of a wavelength component of fluorescence from light emitted from the irradiation position of the excitation light;
Photoelectric conversion means for converting light taken in through the filtering means into an electrical signal;
Waveform shaping means that inverts and amplifies half of the output signal from the photoelectric conversion means while synchronizing with a timing that is 90 degrees out of phase with the irradiation period of the light irradiation means;
Low-pass filtering means for selectively extracting a DC component from the output signal by the waveform shaping means,
An optical reader comprising: comparing means for comparing a detection voltage output from the low-pass filtering means with a set voltage; and outputting a predetermined detection signal when the detected voltage exceeds the set voltage. 5. The waveform shaping unit according to claim 4, wherein the waveform shaping means is connected in parallel to each of two input terminals of the differential amplifier circuit through analog switches, respectively.
One analog switch is turned on in correspondence with the light irradiation period and the 90-degree phase delay,
An optical reading apparatus characterized in that the other analog switch is turned on in correspondence with a light irradiation period and a period in which the phase is advanced by 90 degrees.

Images