JPH09269733A - Invisible marking film and its reading method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an invisible marking film which allows the identification of marking when irradiated with rays invisible with the naked eyes by adjusting the refractive indices of a ground surface film, a printed film obtd. by printing of information with invisible marking ink and a top coating film. SOLUTION: The surface of the ground surface film A is partly formed with the printed film B printed with the information by the invisible marking ink. The surfaces of the ground surface film A and the printed film B are coated with the top coating film C, by which the printed matter is obtd. The films having the refractive indices higher in order of A>=C>B are used for the ground surface film A, the invisible marking printed film B and the top coating film C. The invisible marking printed film B part is detected by a difference in the reflected ray quantity (absorption quantity) between the invisible marking printed film B part and the non invisible marking printed film part (ground surface film) C when the surface of the top coating film C is irradiated with the rays, by which the information of the printed film is identified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel invisible marking film and a reading method thereof.

[0002]

2. Description of the Related Art Conventionally, a bar code made of white and black lines is attached to an object such as an accessory, a part, or a commodity, which is read by an optical device, and the type, price, and sale It is often used to manage numbers, inventory management, etc.
The range of use is expected to become wider in the future. However, the conventional bar code is printed in black and white so that it can be seen with the naked eye, and therefore it is not preferable in terms of the design of the product itself, and it cannot be applied to the easily soiled portion. Originally, the bar code itself is used only for product management and is meaningless to general consumers.

Therefore, there has been proposed a bar code which is invisible to the naked eye and can be discriminated by infrared irradiation. For example, an ink obtained by dispersing indium-tin oxide fine powder as an infrared absorbing compound in a resin is bar-code printed,
A method of irradiating this portion with infrared rays and identifying it has been proposed. In this method, the particle diameter of the fine powder is 0.001 to 0.001.
Since it is necessary to adjust to a range of 0.5 micron, there are problems that it takes time and effort to manufacture the fine powder, and that it is expensive and economically disadvantageous.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, an undercoat, a print film obtained by printing information with an invisible marking ink, and It has been found that by adjusting the refractive index of the overcoat film, all the conventional problems can be solved, and the present invention has been completed. That is, the present invention provides: Information is printed on a part of the surface of the undercoat (A) with an ink for invisible marking to form a print film (B),
Further, a printed matter in which the surface of the undercoat film (A) and the printed film (B) is covered with the overcoat film (C),
The refractive indexes of the coatings of (B) and (C) are (A) ≧ (C)>
(B) Invisible marking film; The coating has a refractive index of 0.01 to 0.01 as compared with (C).
0.3 large invisible marking film above; The refractive index of the coating is 0.01 to 0.01% higher than that of (B).
3. A large invisible marking coating of 0.3; and 4. A method of reading an invisible marking film is provided which detects and identifies the information printed on the invisible marking film by a reader having a light source, a light receiver, an output signal processor, and an external data output terminal. It is a thing.

The imbibli marking coating and the method of reading the same according to the present invention include a base coating (A) having different refractive indexes,
Invisible Marking Printing Invisible Marking Printing by irradiating a light beam (incident light beam) on the surface of the top coat film (C) of the invisible marking film formed by laminating the coating film (B) and the top coat film (C). The invisible marking printing coating portion is detected by the difference in the reflected light amount (absorption amount) between the coating portion and the non-invisible marking printing coating portion (base coating), and the information of the printing coating is identified,
It can be managed.

The above-mentioned difference in the amount of reflected light will be described with reference to FIG. FIG. 1 shows how light rays are reflected and transmitted when they are irradiated on the surface of the invisible marking film. In FIG. 1, I is an invisible marking printed portion laminated with an overcoat (C), an invisible marking printing coating (B), and a base coating (A), and I
Reference numeral I is a non-invisible marking printed portion laminated with the overcoat (C) and the undercoat (A). In I, the light ray (a) incident on the surface of the overcoat film (C) at the incident angle θ ₀ is incident on the layer of the overcoat film (C) at the incident angle θ ₁ and then the invisible marking printing film (B) having a small refractive index. Most of the incident light rays (a) are reflected back on the surface and are detected as reflected light rays (a ″), and some of the light rays (a ′) are transmitted through the invisible marking printing film (B), but are not detected. On the other hand, in (II), the light beam (b) which is incident on the surface of the overcoat film (C) at the incident angle θ ₀ in II is incident on the overcoat film (C) layer at the incident angle θ ₁ and is then refracted. The light beam (b) is incident on the undercoating film (A) layer having a large rate at an incident angle θ _{3. The} light ray (b) passes through the undercoating film (A) when there is no substrate such as a reflector under the undercoating film (A). And does not come back, or if there is a reflective object, it is reflected by the reflective object (the figure shows the substrate Present shows the case) light rays (b ') is not detected as reflected light because light most at the interface portion between the small topcoat film refractive index (C) (b ") is reflected as shown in Figure 1. The remaining light ray (b ') passes through the top coat (C) and returns slightly as a reflected light ray (b ""), but the amount of the light ray is smaller than that of the reflected light ray (a "). The refractive index and the incident angle are expressed by the following equations: Sinθ ₀ = n ₁ Sinθ ₁ , n ₁ Sinθ ₁ = n ₂
Sinθ ₂ and n ₁ Sinθ ₁ = n ₃ Sinθ ₃ (n
₁ is the refractive index of the overcoat (C), n ₂ is the refractive index of the invisible marking printing film (B), and n ₃ is the refractive index of the undercoat (A)).

From these facts, the light rays (a, b) transmitted through the invisible marking printing film (B) and the overcoat film (C) are reflected by the undercoating film (A) (a ',
b "") is small, and a large amount of reflected light (a ") from the invisible marking printing film (B) is detected, and the difference in the amount of reflected light is detected by the S / N ratio to make it invisible. Marking can be identified and managed.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The refractive index of an undercoat (A), an invisible marking printing film (B), and a topcoat (C) used in the present invention is (A) ≧ (C)> (B).
The higher one is used in order. The refractive index of (A) is (C)
When the refractive index is lower than that of (A) and (C), the light ray is reflected at the interface of the coating film and cannot be distinguished from the reflected light ray of (B), so invisible marking cannot be identified.
When the refractive index of (B) is the same as or higher than the refractive index of (C), the incident light ray passes through (B), so that the invisible marking itself of (B) cannot be identified. Further, the refractive indexes of the above (A) to (C) are preferably 0.01 or more, and more preferably 0.1 or more, respectively, in order to distinguish invisible marking more clearly. Further, if the difference between them is too large, the appearance is deteriorated, and therefore it is preferably 0.3 or less, preferably 0.2 or less.

The difference in the refractive index is that the individual coatings of (A) to (C) have a temperature of about 20 ° C. and an incident angle of light (an angle at which the amount of reflected light increases between the marking portion and the non-marking portion). Can be appropriately determined, but it is usually performed at 20 ° to 70 °), and the refractive index is measured by irradiating the detection wavelength (for example, infrared rays, visible rays, ultraviolet rays) rays, and the refractive index is calculated from these measured values. This is the value obtained by calculating the difference.

The coating film of (A) is formed of conventionally known plastic sheets (including films), paints, and inks without particular limitation, as long as it satisfies the above range of refractive index. A coated film or the like can be used.

As the plastic sheets, for example, sheets obtained by melting and stretching plastic chips can be used. Specifically, for example, polyvinylidene chloride (1.63), polychlorostyrene (1.
61), polystyrene (1.59), polycarbonate (1.58), styrene acrylonitrile copolymer (1.56), polyethylene (low density 1.51 to high density 1.54), polyamide (1 .53), polyvinyl chloride (1.52 to 1.55), polyisobutylene (1.5
1), polymethylmethacrylate (1.49), polypropylene (1.49), polyacetal (1.48),
Examples thereof include polyvinyl acetate (1.47) and polymethylpentene (1.46). The plastic sheets may be molded into a cylindrical shape, a box shape, a bag shape, or a spherical shape.

The (A) to (C) coatings obtained by using the plastic sheets are metals (aluminum, tin, iron, stainless steel, copper, alloys containing these, etc.), plastics on the back surface of the (A) coating. It can be used by adhering it to a substrate such as paper, cloth, wood, and glass. As the above-mentioned paint and ink, formed by using a paint and an ink resin in which the refractive index of the film falls within the above-mentioned range, if necessary, with addition of a solvent such as an organic solvent or water or a dispersion medium. can do. Examples of resins for paints and inks include polyester resins, epoxy resins, vinyl resins, urethane resins, polyamide resins and acrylic resins. These may be thermoplastic, normal temperature curing or heat curing type. To cure the resin, a curing agent such as a melamine resin, a urea resin, a polyisocyanate compound, a polycarboxylic acid or an epoxy compound can be added, if necessary. These coatings and inks can be formed on these films by coating and printing on a substrate (for example, the above-mentioned substrates and the like). As the coating, for example, spray coating, brush coating, roller coating, bar coater coating, knife coater coating and the like can be performed, and as the printing, for example, gravure printing, It can be performed by silk printing, offset printing, an inkjet method, or the like.

The undercoat of (A) above may be a clear coat or a colored coat. The film thickness of this material is generally about 20 to 10000 microns, preferably about 30 to 500 for plastic sheets.
In the range of 0 micron, and in coatings and printed coatings (dry) about 1-100 microns, preferably about 2-80.
In the micron range.

The coating film of (B) can be obtained by printing a conventionally known ink on the undercoating film of (A) without particular limitation, as long as it satisfies the above range of refractive index. it can. As the ink, the same ink as the above-mentioned ink can be used. In addition, printing can be performed by the same method as described above. The film thickness (dry) of this product is generally in the range of about 0.5 to 50 μm, preferably about 1 to 20 μm.

The coating of (B) above may be a clear coating or a colored coating, but when a colored coating is used, the coating of (C) above is the coating of (B). A colored coating is used so that the coating is invisible to the naked eye.

The information to be printed is not particularly limited, and for example,
Letters, numbers, symbols, marks, patterns, etc. can be used, and specific examples include bar code, manufacturing date, lot number and the like.

The coating film of (C) is not particularly limited as long as it satisfies the above range of refractive index, and a conventionally known coating material is used as the undercoat film of (A) and the coating film of (B). It can be obtained by painting. As the paint resin, the same resins as those mentioned above can be used.
The coating can be performed by the same method as described above. The film thickness of this is generally in the range of about 1 to 100 microns, preferably about 3 to 50 microns. The coating of (C) may be a clear coating or a colored coating.

The present invention also provides an invisible marking for detecting and identifying information printed with the invisible marking ink of the above invisible marking coating by a reader having a light source, a light receiver, and an output signal processor. A method of reading a coating is provided.

A method of reading an invisible marking coating according to the present invention will be described below.

In the reading method, the invisible marking coating portion is detected by the difference in the light reflection amount (absorption amount) between the invisible marking coating portion and the non-invisible marking coating portion of the invisible marking coating. It identifies the information represented by the coating.

FIG. 2 shows an outline of the structure of the reader. The components are a light source, a light receiver, an output signal processing device for decoding the read data of the invisible marking section, and an external data output terminal.

It is preferable to use a single wavelength light beam as the light source. A light beam having a wavelength range of about 1 mm to 10 nm can be used. The types of light rays include infrared rays, ultraviolet rays, and laser light rays (He-Ne laser light source, L
D laser light source, etc.) can be used. Of these, laser light is particularly preferable. The light beam emitted from the light source is collimated (parallel) by a collimating lens and incident on the surface of the invisible marking film, or is guided from the light source to a predetermined position using an optical fiber, It is possible to collimate the outgoing ray of light by means of a collimating lens and make it enter the surface of the invisible marking film. The effective ray incident angle (θ ₀ ) incident on the surface of the invisible marking film may be appropriately determined depending on the refractive index of each film forming the invisible marking film and the difference between these refractive indices. Specifically, for example, the angle of light rays incident on the surface of the topcoat film (C) is θ ₀ , the refractive index of the topcoat film (C) is n _1, and
And when the refractive index of the invisible marking printed film (B) is n ₂ , the incident ray angle θ ₀ is expressed by the following equation: Sin θ
_If the condition of ₀ ≧ (n ₂ / n ₁ ) is satisfied, total reflection occurs and the ideal incident condition is obtained. Further, even if the above-mentioned incident conditions are not satisfied, the light rays transmitted through the invisible marking printing film or the rays passing through the non-invisible marking coating film with respect to the reflected light rays of the invisible marking printing film (B) are used as the base coating. It may be set so as to be absorbed by (A) so that the amount of reflected light is reduced. The incident ray angle is not particularly limited, but is preferably in the range of about 20 to 70 °, preferably about 30 to 60 °. The distance between the light source and the surface of the invisible marking film may be such that stray light or scattered light does not adversely affect the detection, and is generally about 20 mm to 10 mm.
A range of 0 mm is suitable. When the light source cannot be installed at a predetermined position, an optical fiber can be used to guide the light at an appropriate distance.

As the light receiver, it is possible to use a light receiver which converts an optical signal into an electric signal according to the wavelength of the light source. Specifically, a photodetector such as a silicon photo diode or a germanium photo diode can be used. Further, the light guide line is collimated by the collimating lens before the reflected light beam is guided to the light receiver. As with the distance between the light source and the invisible marking film, the distance between the light receiver and the surface of the invisible marking film may be such that stray light or scattered light does not adversely affect the detection, and is generally about A range of 20 mm to 100 mm is suitable. When the light source cannot be installed at a predetermined position, an optical fiber can be used to guide the light at an appropriate distance.

The output signal processing device is a device for reading the output signal (marking) detected by the light receiver. An outline of the reading method is shown in FIGS. 3 and 4. FIG. 3 is a schematic cross-sectional view showing how a light ray is made incident on the surface of the invisible marking film and reflected. FIG. 4 shows the invisible marker of FIG.
FIG. 6 is a schematic diagram in which a reflected light ray on the surface of the king printed film is used as an S signal, a reflected light ray on the surface of the non-invisible marking film is used as an N signal, and a reading threshold value is set based on the obtained S / N ratio. By reading the signal, the marking portion can be detected.

[0025]

EXAMPLES The present invention will be described more specifically below with reference to examples.

Example 1 Vinyl deluxe white (trade name, Kansai Paint Co., Ltd., acrylic resin emulsion paint, coating film refractive index N _{D on an} aluminum plate (thickness: 0.3 mm; hereinafter the same))
≧ 1.485) is coated with a bar coater so that the dry film thickness is about 5 μm, and dried to form a base film,
Then, on a part of the surface of the undercoat, a silicone-based clear-
Gravure the ink (coating refractive index N _D = 1.467)
Printing to a dry film thickness of about 5 microns and drying to form invisible marking printing coatings, and the coatings of Paraloid A-1 on the surface of these coatings.
1 (Rom & Haas Co., trade name, acrylic resin organic solvent solution, coating refractive index N _D = 1.484) with a dry film thickness of 5
It was coated with a bar coater so as to have a thickness of micron and dried to form an overcoat film to obtain an invisible marking film. The coating was not visually recognizable for invisible marking.

In an atmosphere at room temperature of 25 ° C., a light beam (wavelength: 633n) is applied to the surface of the invisible marking film obtained above.
m, He-Ne laser light) is irradiated through a collimating lens at an incident angle of 60 ° (the distance between the light source and the irradiation point of the film is 50 mm), and the reflected light is received through the collimating lens. The light was received (the distance between the silicon photo diode, the light receiver and the reflected light point of the coating was 50 mm). As a result of measuring the attenuation of the reflected light quantity, there was an attenuation of -10 decibels between the invisible marking portion and the non-invisible marking portion, which was good because the marking portion could be clearly identified.

Example 2 Retan PG-80 Bull (trade name, manufactured by Kansai Paint Co., Ltd., a two-component urethane acrylic paint, coating film refractive index N _D ≧ 1.458) was applied to an aluminum plate base material so that the dry film thickness was about 1. Fifty
It is coated with a bar coater so as to have a micron size, and dried and cured to form an undercoat, and then a fluorine-based clear ink (film refractive index N _D = 1.43) is formed on a part of the surface of the undercoat.
9) is printed by a gravure coater so that the dry film thickness is about 5 μm, and dried to form an invisible marking printing film, and further, an epoxy-based paint ( A coating film having a refractive index of N _D = 1.457) was coated with a bar coater so that the dry film thickness was 80 μm, and dried to form an overcoat film to obtain an invisible marking film. The coating was not visually recognizable for invisible marking.

In an atmosphere at room temperature of 25 ° C., a light beam (wavelength: 670 n) was applied to the surface of the invisible marking film obtained above.
m, LD-laser light) is guided using an optical fiber, and is irradiated through a collimating lens at an incident angle of 30 ° (the distance between the optical fiber and the irradiation point of the coating is 20 mm) and reflected. A light beam is passed through a collimating lens to a light receiver (silicon photodiode, the distance between the light receiver and the reflected light point of the coating is 20
mm). As a result of measuring the attenuation of the amount of reflected light, there was an attenuation of -8 decibels between the invisible marking portion and the non-invisible marking portion, and the marking portion could be clearly discriminated.

Example 3 Polyvinyl chloride sheet white (thickness 30 μm, film refractive index N _D ≧ 1.478) was used as an undercoat, and a polysiloxane clear ink (film refractive index N _D = 1.400) is printed with a gravure coater so that the dry film thickness is about 2 microns, and dried and cured to form an invisible marking printing film, and the surface of these films Acrylic clear paint (refractive index N _D = 1.477) was coated on the above bar coater to a dry film thickness of 20 μm and dried to form a top coat. The coating was not visually recognizable for invisible marking.

In the same manner as in Example 1, a light beam (however, the incident angle of the light beam was 40 °) was irradiated and the attenuation of the reflected light amount was measured. As a result, the invisible marking portion and the non-invisible marker There was an attenuation of -12 decibels with the king part, and the marking part was clearly distinguishable, which was good.

Example 4 Acrylic plate (thickness 100 μm, refractive index N _D ≧ 1.4
82) as a base, polyvinyl acetate clear ink (coating refractive index N _D = 1.471) is printed on a part of the surface of this product with an ink jet to print a number of 10-point character size (about 10 microns), and dried. Then, an epoxy phenol type clear coating (refractive index N _D = 1.481) was coated on the bar coater so that the dry film thickness was about 20 μm,
Dry-curing was performed to form an overcoat film to obtain an invisible marking film. The coating was not visually recognizable for invisible marking.

In the atmosphere at room temperature of 25 ° C., a light beam (LED laser) is applied to the surface of the invisible marking film obtained above.
The light beam is irradiated through the collimating lens at an incident angle of 45 ° (the distance between the light source and the irradiation point of the coating is 100 mm), and the reflected light beam is received through the collimating lens into a light receiver (germanium photo diode, light receiver). The light was received at a distance of 100 mm from the reflected light point of the coating. As a result of measuring the attenuation of the reflected light quantity, there was an attenuation of -10 decibels between the invisible marking portion and the non-invisible marking portion, which was good because the marking portion could be clearly identified.

[0034]

INDUSTRIAL APPLICABILITY The marking formed according to the present invention is useful as an invisible marking because the marking itself is invisible to the naked eye but the printed matter can be identified by irradiating it with a light beam. It is something.

[Brief description of drawings]

FIG. 1 shows how light rays are reflected and transmitted when a light ray is irradiated on the surface of an invisible marking film.

FIG. 2 shows an outline of the configuration of a reader.

FIG. 3 shows a state in which a light ray is incident on and reflected on the surface of an invisible marking film.

FIG. 4 shows the reflected light on the surface of the invisible marking printed film as the S signal, and the reflected light on the surface of the non-invisible marking film as the N signal (FIG. 3), and reads from the obtained S / N ratio. An outline of setting a threshold value is shown.

[Explanation of symbols]

 I Invisible Marking Printed Area II Non-Invisible Marking Printed Area a Incident Ray a ′ Transmitted Ray a ″ Reflected Ray b Incident Ray b ′ to b ″ ′ Reflected Ray θ Angle A Undercoat B Invisible Marking Printed C Top coat

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiaki Nagano 4-17-1, Higashi-Hachiman, Hiratsuka City, Kanagawa Kansai Paint Co., Ltd. (72) Inventor, Takashi Tsumuma 1440, Rosaki, Sakura-shi, Chiba Fujikura Sakura Co., Ltd. Inside the factory (72) Inventor Tomoaki Toritani 1440 Rokuzaki, Sakura-shi, Chiba Fujikura Sakura Co., Ltd. Inside the factory (72) Masanobu Hidaka 2-3-3-8 Shin-Yokohama, Shin-Yokohama, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture Shin-Yokohama Building B Inside Matsuo Sangyo Co., Ltd.

Claims (4)

[Claims] 1. A printed film (B) in which information is printed on a part of the surface of the underlying film (A) with an ink for invisible marking.
And a surface of the undercoating film (A) and the printing film (B) are covered with an overcoating film (C), and the refraction of the above coating films (A), (B) and (C) Rate is (A)
An invisible marking film, wherein ≧ (C)> (B). 2. The invisible marking coating according to claim 1, wherein (A) has a refractive index of 0.01 to 0.3 larger than that of (C). 3. The invisible marking film according to claim 1, wherein (C) has a refractive index of 0.01 to 0.3 larger than that of (B). 4. A reader having a light source, a light receiver, an output signal processing device, and a data external output terminal.
A method for reading an invisible marking film, which comprises detecting and identifying information printed on the invisible marking film according to claim 1.