JPH05131787A - Information recording medium - Google Patents

Abstract

PURPOSE:To make it impossible to visually discriminate information pattern without losing decorative effect by providing diffraction grating pattern including parts consisting of material having a light region without absorption and an infrared region with absorption. CONSTITUTION:There is provided a diffraction grating pattern including a part 1 consisting of a material (for example, infrared ray absorbing colorless phosphate glass powder) not having absorption at a light region and having absorption at an infrared region. That is, on a base material film 2, a peeling layer 3, an infrared ray absorbing layer 1, a diffraction grating forming layer 4, a reflective layer 5 and an adhesive layer 6 are provided so as to constitute an information recording medium for optical mechanical reading. As a result, visual discrimination of information pattern will be impossible without losing decorative effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium having a diffraction grating pattern and intended for optical mechanical reading.

[0002]

2. Description of the Related Art Conventionally, when a diffraction grating is used as an information pattern, information is displayed by changing the spatial frequency of the diffraction grating, changing the direction of the diffraction grating, or a combination thereof. ..

Further, as a method of reading the information contained in the diffraction grating pattern, there are a method of utilizing the diffraction angle of the diffracted light and a method of detecting the direction of the diffracted light.

As a light source used for reading such information, a semiconductor laser in the infrared wavelength region is generally used in terms of cost and simplicity.

On the other hand, as a method of manufacturing an information recording medium having the above-mentioned diffraction grating, a mold on which the concavo-convex shape of the diffraction grating is recorded is pressed and brought into close contact with a plastic film to reproduce the concavo-convex pattern, and the reproduced plastic is reproduced. A well-known method is to form a reflective layer on the uneven surface of a film by vapor deposition of metal or the like.

The reflection type diffraction grating thus formed is used as an information recording medium for optical reading as a transfer type film or a laminating type film.

[0007]

When the conventional diffraction grating film as described above is used as the information pattern, the existence of the diffraction grating can be visually confirmed, and therefore, when a person having knowledge of reading the diffraction grating sees, There is a drawback that it is easy to determine what kind of information pattern is used.

In order to prevent such a defect, it is general to take measures such as concealing the diffraction grating pattern by using a material that does not transmit light in the visible region but only light in the infrared region. Has been taken by.

However, when the above measures are taken,
The information pattern can be concealed, but the decoration effect of the diffraction grating is lost, and the effect of sales promotion due to the decoration effect is lost.

It is an object of the present invention to provide an information recording medium having a diffraction grating used for optical mechanical reading, in which the information pattern cannot be visually identified without losing the decorative effect. And

[0011]

DISCLOSURE OF THE INVENTION As a result of intensive studies conducted by the present inventors in view of the above-mentioned problems, the above-mentioned object of the present invention is that a portion made of a material having no absorption in the visible light region and absorption in the infrared region. An information recording medium for optical mechanical reading having a diffraction grating pattern containing, in particular, an information recording medium having no absorption in the visible light region and having an absorption in the infrared region made of infrared absorbing colorless phosphate glass powder It has been found that it is achieved by providing. Furthermore, it was found that the object of the present invention can be effectively achieved when the information recording medium is a transfer type film or a laminating type film.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below more specifically with reference to the drawings.

The optical mechanical reading method described below describes the case of detecting only the first-order diffracted light of a single diffraction grating, but the same applies to the detection of diffracted light of the second or higher order. The same applies to a method of reading a diffraction grating pattern composed of two or more kinds of minute areas.

FIG. 1 is a sectional view showing the construction of an embodiment of a transfer type film which is an information recording medium of the present invention, and FIG. 2 is a sectional view of an embodiment of a bonding type film which is an information recording medium of the present invention. It is sectional drawing which shows a structure.

In FIG. 1 or 2, the base film 2
The infrared absorption layer 1, with or without the release layer 3 interposed therebetween,
The diffraction grating forming layer 4, the reflecting layer 5, and the adhesive layer 6 are provided. As the base film 2, any film-shaped material can be used. It is desirable that the base film 2 has little absorption in the infrared region.

In the case of a transfer type film, the peeling layer 3 has a role of providing peelability between the substrate film 2 and the diffraction grating layer 4, and also providing printability of the surface after transfer and protection of the diffraction grating layer. And is made of a material such as acrylic resin. It is desirable that the release layer 3 also has a small absorption in the infrared region, like the base film 2.

The diffraction grating forming layer 4 is composed of a thermoplastic resin, a resin having a thermoformability which is cured by ultraviolet rays or electron beams, or a thermosetting resin having a thermoformability, and the surface of these resins is diffracted. The grid is formed in an uneven pattern.

The diffraction grating forming layer 4 is formed by the method described in the above-mentioned section of the prior art by a duplication method using a diffraction grating original plate having a diffraction grating formed on the surface in a concavo-convex pattern, for example, urethane resin or the like. Composed of materials.

It is desirable that the diffraction grating forming layer 4 as well as the base film 2 has a small absorption in the infrared region.

The reflection layer 5 can be formed by vapor-depositing a metal such as aluminum or tin and plays a role of infrared reflection.

The adhesive layer 6 plays a role of adhering the transfer sheet to a card or a cover of a book, and is specifically made of a material such as urethane, vinyl chloride and polyester.

The infrared absorption layer 1 having no absorption in the visible light region and absorption in the infrared light region is obtained by pulverizing a material made of infrared absorbing colorless phosphate glass into an ink as a pigment,
What is formed by a printing method such as screen printing is used. Such an infrared-absorbing colorless phosphate glass preferably contains phosphorus pentoxide as a main component and contains iron oxide and / or copper oxide in an amount of 1.0% by weight or more.

The powdered phosphate glass preferably contains phosphorus pentoxide in a weight percentage of 35.0 to 80.0% and iron oxide and copper oxide in an amount of 0 to 3.0%, respectively.
Further, the above phosphate glass contains the following compounds, if necessary.

Al ₂ O ₃ 2.0 to 10.0 wt% B ₂ O ₃ 1.0 to 30.0 wt% MgO 3.0 to 10.0 wt% ZnO 0 to 3.0 wt% K ₂ O 0 to 15.0 wt% BaO 0 to 10.0 wt% SrO 0 to 1.0 wt% Ni, Co, Se Trace amount

The phosphate glass powder used in the present invention is a powder of the phosphate glass obtained above, and the present invention uses the pigment glass as an ink.

It is preferable that 80% by weight or less of the powdery phosphate glass is contained in the printing ink composition excluding the solvent. If it exceeds 80% by weight, a mat-like structure is formed, and the glass surface is reflected, that is, infrared light is reflected.
In addition, the cohesive force is also limited, and the adhesiveness and scratch strength are also reduced.

As the binder contained in the infrared absorbing printing ink used in the present invention, vinyl chloride acetate resin, saturated polyester, polyurethane elastomer and the like are used.

The binder is preferably contained in the printing ink composition excluding the solvent in an amount of 20% by weight or less.

The infrared absorbing layer 1 is preferably laminated between the peeling layer 3 (or the base film 2) and the diffraction grating layer 4 as shown in the structural examples of FIGS. 5 may be stacked on top of each other in any order.

FIG. 3 shows an example of a method for performing optical mechanical reading of the information recording medium as described above. When a laser beam is irradiated as the irradiation light 9 from directly above the diffraction grating pattern 7, the diffraction light 10 is diffracted and returned in the direction perpendicular to the direction of the line of the diffraction grating. In the case of this reading method, the information code is recorded by changing the grating direction of the diffraction grating.
In actual reading, a reading sensor 8 using a photodiode as shown in FIG. 4 is arranged at a predetermined position,
The diffracted light in the two directions A and B can be detected. For example, the sensor 11 can receive the diffracted light in the A direction and the sensor 12 can receive the diffracted light in the B direction. As the reading laser, for example, a semiconductor laser with a wavelength of 780 nm can be used.

As the shape of the diffraction grating pattern, as shown in FIG. 5, for example, a rectangular array of 2 mm × 10 mm is used. As the diffraction grating that forms the area, for example, two types having a spatial frequency of 700 line / mm and the directions of the diffraction grating forming an angle of 90 degrees are used.

6 and 7 show examples of printed patterns of the infrared absorption layer having the diffraction grating pattern shown in FIG.

According to the diffraction grating pattern shown in FIG.
If the diffraction grating 14 in the direction is a 0 bit and the diffraction grating 15 in the B direction is a 1 bit, the code of 01010101 is displayed. FIG. 8 shows an analog output waveform when the diffraction grating pattern shown in FIG. 5 is read.

Next, as shown in FIGS. 6 and 7, the infrared absorbing layer printing pattern α16 and the infrared absorbing layer printing pattern β17 are printed as printing patterns on the diffraction grating pattern shown in FIG. Diffraction grating film α18, diffraction grating film β19
Was produced.

Since the diffraction grating films α and β shown in FIGS. 6 and 7 look similar to the diffraction grating pattern shown in FIG. 5 with the eyes, the difference between the patterns of FIGS. 6 and 7 is visually observed. It is difficult to determine by.

Diffraction grating film 1 shown in FIGS. 6 and 7.
The analog output waveforms when 8 and 19 are read are shown in FIG.
And shown in FIG. The diffraction efficiency of the diffraction grating in the portion where the infrared absorbing layer is printed is reduced because the infrared absorbing layer has absorption in the infrared region which is the reading wavelength. For this reason,
With analog output, only 0.5V output can be obtained. On the other hand, the area where the infrared absorption layer is not printed is 3V
The output of the degree is obtained. Here, when the slash level is set to 1 V and digital conversion is performed, each of FIG.
A digital output as shown in FIG. 12 was obtained. When this digital output is converted into a code, the output in FIG.
Since the code of 01 and the code of 0110 are displayed in the output of FIG. 12, the difference in the diffraction grating patterns of the diffraction grating films of FIGS. 6 and 7 can be discriminated by a machine.

[0037]

As described above, the information recording medium of the present invention has a specific portion having no absorption in the visible light region and absorption in the infrared region in the diffraction grating pattern, so that the decorative effect is not impaired and the information It is possible to make visual identification of the code impossible. As a result, it is possible to obtain an information recording medium having a superior anti-counterfeit effect that does not impair the decorative effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing the constitution of one example of a transfer type film which is an information recording medium of the present invention.

FIG. 2 is a cross-sectional view showing the constitution of one example of the sticking type film which is the information recording medium of the present invention.

FIG. 3 is a schematic view showing an example of a reading method for reading the diffraction grating pattern of the diffraction grating film of the present invention.

FIG. 4 is a plan view showing a reading sensor unit of the reading device used in the present invention.

FIG. 5 is an explanatory diagram showing an example of a diffraction grating pattern that can be used in the present invention.

FIG. 6 is an explanatory diagram showing an example of a print pattern of an infrared absorption layer that can be used in the present invention.

FIG. 7 is an explanatory diagram showing an example of a print pattern of an infrared absorption layer that can be used in the present invention.

FIG. 8 is an analog output waveform diagram obtained when the diffraction grating pattern 7 used in the present invention is read by a sensor.

FIG. 9 is an analog output waveform diagram obtained when the diffraction grating film 18 used in the present invention is read by a sensor.

FIG. 10 is an analog output waveform diagram obtained when the diffraction grating film 19 used in the present invention is read by a sensor.

FIG. 11 is a digital output waveform diagram obtained when the diffraction grating film 18 used in the present invention is read by a sensor.

FIG. 12 is a digital output waveform diagram obtained when the diffraction grating film 19 used in the present invention is read by a sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Infrared absorption layer 2 Base film 3 Release layer 4 Diffraction grating formation layer 5 Reflection layer 6 Adhesive layer 7 Diffraction grating pattern 8 Reading sensor part 9 Irradiated light 10 Diffracted light 11 Sensor for receiving diffracted light in A direction 12 B direction Sensor for receiving diffracted light 13 Light source 14 Diffraction grating whose grating direction is A direction 15 Diffraction grating whose grating direction is B direction 16 Infrared absorbing layer printing pattern α 17 Infrared absorbing layer printing pattern β 18 Diffraction grating film α 19 Diffraction grating film β

Claims (4)

[Claims] 1. An information recording medium for optical mechanical reading having a diffraction grating pattern including a portion made of a material having no absorption in the visible light region and absorption in the infrared region. 2. The information recording according to claim 1, wherein the material having no absorption in the visible light region and the absorption in the infrared region according to claim 1 is infrared absorbing colorless phosphate glass powder. Medium. 3. An information recording transfer type film for optical mechanical reading having a diffraction grating pattern including a portion made of a material having no absorption in a visible light region and an absorption in an infrared region. 4. An information recording laminated film for optical mechanical reading, which has a diffraction grating pattern including a portion made of a material having no absorption in the visible light region and absorption in the infrared region.