JP4303992B2 - Light diffraction structure and hidden pattern discrimination tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the determination instrument optical diffraction structure及 originator including hard hidden patterns determined in normal viewing conditions.
[0002]
[Prior art]
In recent years, forgery cases of high-value banknotes and gift certificates using color copiers have frequently occurred.
For this reason, high-value banknotes and gift certificates have a small halftone dot or fine line that cannot be read by a color copier sensor in a part of the design, and is incorporated in a pattern designed with the same reflection density. As a result, when trying to copy these high-value banknotes and gift certificates with a color copier, the copier scanner reads out small dots and fine lines, and those parts are identified as white and are identified as copies. .
[0003]
In addition, a method of discriminating a copy product by providing a brilliant metal part in a part of the design of the printed material is also implemented.
Since such a metal part regularly reflects incident light, the copying machine reproduces this part in black. For example, a gold thread is sewed on the surface layer of paper to check the copy.
[0004]
In addition, a metal reflective surface is formed by vapor deposition or the like on the concave and convex surface of the light diffractive structure replicated with a transparent resin, thermally transferred to a part of the printing area, and the copying by the copying machine is restrained.
The light diffractive structure is often used as a means for preventing counterfeiting of vouchers because it requires advanced manufacturing techniques.
However, in recent years, a technology close to a light diffraction structure has appeared, and it has become possible to reproduce effects similar to those of a light diffraction structure.
Therefore, in order to check such an approximation technique, a technique is disclosed in which a hidden pattern that is difficult to discriminate is incorporated into an optical diffraction structure and used as a means for discriminating authenticity (see, for example, Patent Document 1).
However, the disclosed technique has a problem that the portion where the hidden pattern is formed is slightly discriminated depending on the viewing angle.
[0005]
[Patent Document 1]
JP-A-11-277962 [0006]
[Problems to be solved by the invention]
The present invention has been made in view of such a problem, and provides a hidden pattern that has a large anti-counterfeit effect, is extremely difficult to discriminate by visual means, and is difficult to duplicate, and its discriminator.
[0007]
[Means for Solving the Problems]
To achieve the purpose of the above problems, the light invention described in 請 Motomeko 1 of the present invention, including the difficult patterns (hidden patterns) and distinguishable pattern judgment by the diffraction grating formed in the flat portion of the base body A diffractive structure,
The difficult-to-discriminate pattern and the discriminable pattern are formed of stripes in which either a pair of two band pairs or a pair of two dot pairs are regularly arranged , A pair of bands or dots are formed by different diffraction gratings .
[0008]
The invention according to claim 2 is characterized in that, in the invention according to claim 1, the pattern that is difficult to discriminate is formed so as to cover a part of the discriminable pattern.
[0009]
According to a third aspect of the present invention, in the invention according to any one of the first to second aspects, the one of the stripes or the diffraction grating formed on one of the plurality of dots is the other band. Alternatively, it is characterized in that at least one of a pitch and a diffraction angle is different from that of a diffraction grating formed on adjacent dots.
[0010]
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the stripe width is 0.2 mm or less.
The invention described in claim 5 is characterized in that, in the invention described in any one of claims 1 to 4, the width of the dot is approximate to the width of the band.
[0012]
The invention according to claim 6 is a discriminator for discriminating a hidden pattern by the light diffraction structure according to any one of claims 1 to 5, and is any one of a pattern that can discriminate parallel straight lines and a pattern that is difficult to discriminate. It is characterized in that it is formed on a transparent substrate at a pitch close to the pitch of one pattern stripe.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the hidden pattern and the discriminating tool by the light diffraction structure of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram for explaining an example of a printed material to which a light diffraction structure having a hidden pattern of the present invention is transferred and its discriminating tool, and FIG. 2 is a diagram for explaining an embodiment in which a hidden pattern is generated by the discriminating tool. FIG. 3 is an enlarged view of a part of the entire region of FIG. 1, FIG. 4 is an enlarged schematic view of the partial region of FIG. 3, and FIG. 5 is a diffraction angle and a built-in angle of the partial region shown in FIG. FIG. 6 is a diagram for explaining an aggregate of two bands forming a pair, FIG. 7 is a diagram for explaining the density of stripes, and FIG. 8 is a diagram for explaining dots. FIG. 10 is a diagram for explaining an embodiment of the present invention, FIG. 10 is a diagram showing an embodiment of the border, FIG. 11 is a diagram for explaining a state in which a hidden pattern is discriminated by a discriminator, and FIG. FIG. 13 is a diagram for explaining the configuration, and FIG. A-A line cross-sectional view and a.
[0014]
In FIG. 1, a light diffraction structure is formed in the lower right portion of the substrate 5.
The light diffractive structure includes a design element but also includes a true / false discrimination element, and is formed on a flat portion of the substrate so as to be easily discriminated.
The substrate 5 may be various materials such as paper, metal, and plastic.
The entire region 4 by the light diffraction structure is incorporated in the background pattern 2 and can be discriminated in a normal state (hereinafter referred to as a visible pattern) 3-1, 3-2 and a pattern 1 that is difficult to discriminate (hereinafter referred to as a hidden pattern). .) Is formed.
[0015]
If the visible pattern 3-1 of the embodiment shown in FIG. 1 is a credit card, for example, the letters “ABC” are formed as a company logo, and the visible pattern 3-2 is also the application name of the card “ CREDIT "is formed so that it can be seen in a normal state.
In FIG. 1, the hidden pattern 1 “10/02” that can be discriminated when the discriminating tool 6 described in FIG. 2 is held is incorporated in the area of the visible pattern 3-2.
In the prior art, when such a hidden pattern is put into practical use, an independent area is provided outside the character pattern “CREDIT” of the visible pattern 3-2, and the character “CREDIT” of the visible pattern 3-2 is formed. It was by the method of forming avoiding.
In such a method, there is a problem that a large area is required as a formation area of the optical diffraction structure, and any of them is easily determined to be a counterfeit check area, and a clue for counterfeiting is given.
[0016]
With reference to FIG. 2, a method for determining a hidden pattern will be described.
In the embodiment of FIG. 2, a light diffraction structure is formed on the surface of the substrate 5 by a method such as thermal transfer. As shown in FIG. 1, the optical diffraction structure formation area is recognized as a design area of “ABC CREDIT” in which the logo “ABC” or “CREDIT” is simply visible as shown in FIG.
When the discriminator 6 is turned over, a number “10/02” appears as the hidden pattern 1 in the area “CREDIT” which is the visible pattern 3-2.
This number can be useful when the substrate, for example a credit card, is found to be “10/02” or a lot manufactured in October 2002 and a problem occurs with the card itself.
[0017]
The logo “ABC” of the visible pattern 3-1 can be generated by the discriminator when the discriminator 6 is turned.
[0018]
An embodiment of a diffraction grating formed with a visible pattern and a pattern that is difficult to distinguish will be described with reference to FIGS. 3, 4, and 5.
The pattern shown in FIG. 3 is an enlarged view of a part of the entire area of FIG. 1, but “C” and “R” of the visible pattern 3-2 are changed to “0” of “10” of the hidden pattern 1. It shows that they are overlapped.
FIG. 4 is an enlarged view of a part of the overlapping portion of the visible pattern 3-2 and the hidden pattern 1 in FIG. 3, but on the left side of “R” 320 of the visible pattern 3-2, a partial pattern of the visible pattern. It can be seen that 321 overlaps the hidden pattern 120.
The light diffractive structure 4 usually looks as shown in FIG. 1 in a visually observed state. However, when the discriminating tool is superimposed on the FIG.
That is, in the portion of “0” of “10” in FIG. 2, when the discriminator is overlapped, the partial pattern 321 of the visible pattern disappears and is replaced with the hidden pattern 1 (120) and displayed.
[0019]
The table data shown in FIG. 5 shows that the background pattern 200, the hidden pattern 120, the visible pattern 320, and the partial pattern 321 of the visible pattern in FIG. It shows that.
The built-in angle here refers to the number of angles with respect to the reference line where the stripe is located when a group of stripes in the same direction or a group of stripes is patterned and incorporated into another pattern. This is an angle indicating whether or not
[0020]
With reference to FIG. 4 and FIG. 5, the reason why the partial pattern 321 of the visible pattern becomes a visible state without using the discriminator will be described.
Here, it is assumed that it is invisible when it is assimilated to the background pattern 200 and is visible when it is not assimilated.
[0021]
In FIG. 5, when the diffraction angle is the same as the background pattern 200 among the patterns formed by the striped elements (the strips themselves and the aggregate of the striped dots), they are assimilated to the background pattern and become invisible. It is in a state.
That is, the background pattern 200 is a group of strips (described with reference to FIGS. 8 and 9) in which the hidden pattern 120 and the diffraction angle of the diffraction grating are common and are 0 ° and 30 ° (described with reference to FIGS. 8 and 9). Is composed of striped elements having a diffraction angle of 45 ° and 75 ° in common.
These diffraction gratings have the same diffraction grating pitch and different diffraction angles as described above.
[0022]
On the other hand, when viewed from the angle of incorporation, it can be seen that the angle of incorporation is divided into a 45 ° portion and a 135 ° portion.
That is, when the discriminating tools are stacked, the visible pattern and the hidden pattern are distinguished and visually recognized by the difference in diffraction angle.
That is, the angle of incorporation is 135 ° for the background pattern 200 and the visible pattern 320, and 45 ° for the hidden pattern 120 and the partial pattern 321 of the visible pattern.
[0023]
Next, the stripe configuration will be described with reference to FIG.
The stripe (one pair of bands) 1400 is composed of two bands (band 1200 and band 1300) in which an optical diffraction structure is formed.
The band 1200 is formed of a diffraction grating that differs from the band 1300 in at least one of the diffraction angle and the pitch. For example, in FIG. 6, the band 1200 is formed with the diffraction angle of the diffraction grating falling to the right, and the band 1300 is formed with the diffraction angle of the diffraction grating rising to the right.
In this way, two bands of diffraction gratings formed at different diffraction angles or pitches form a pair to form a stripe, forming a light diffraction structure, forming a discriminable pattern and a pattern that is difficult to discriminate is doing.
[0024]
In order to enhance the concealing effect, it is preferable that the density of the bands constituting the stripes is preferably 5 or more in 1 mm, as shown in FIG. It became clear by the experiment of the person.
The purpose of reducing the number of stripes is to make it difficult to visually recognize the hidden pattern, to increase the definition of the entire light diffraction structure, and to facilitate discrimination by the discrimination pattern.
Regarding the upper limit, the inventor is not particularly limited because there is a relation such as the width and length of the constituent units constituting the diffraction grating.
[0025]
With reference to FIG. 8, the fringe comprised with the diffraction grating is demonstrated.
When the stripe 1400 constituted by the two bands 1200 and 1300 in FIG. 6 is enlarged, it is as shown in FIG. 8, and the structural units of the stripes are arranged in an orderly manner.
These structural units are regularly arranged at the same diffraction angle and the same pitch for one band.
For example, for the band 1200 and the band 1300, the pitches of the constituent units of the diffraction gratings are the same, the diffraction angle is changed by 30 ° as shown in FIG. 8, the band 1200 is set to 0 °, and the band 1300 is set to 30 °. As shown in FIG. 4, it is more difficult to distinguish a hidden pattern when it is incorporated into a background pattern.
[0026]
Further, as shown in FIG. 9, the background pattern and the visible pattern are configured by dot-like aggregates 2100 and 2200 of dots arranged at a predetermined angle.
When the dots of the dot band aggregate 2100 are formed at a diffraction angle of 0 ° as in the background pattern, the dots of the dot band aggregate 2200 are formed at a diffraction angle of 30 °, and as in the visible pattern. In the case where the dots of the band-like aggregate 2100 of dots are formed at a diffraction angle of 45 °, the dots of the band-like aggregate 2200 of dots are formed at a diffraction angle of 75 ° and are hidden when the incorporation angle is changed. It becomes possible to make it more difficult to discriminate.
[0027]
The hidden pattern and the visible pattern are incorporated so that the striped group intersects at a right angle as described in FIG.
That is, the entire region is placed at a normal observation position, the stripes of the hidden pattern 120 are incorporated at an angle of 45 °, and the stripes of the visible pattern 320 and the background pattern 200 and the stripe pattern are incorporated at an angle of 135 °.
As a result, the viewer is positioned at an angle that is easy for the observer to visually recognize, and the light reflected from the light diffraction structure amplifies the contrast so that the hidden pattern can be easily seen by the discriminator.
[0028]
FIG. 10 is an embodiment of the edging. By forming the fringe pattern 10 with a fringe having a period shifted by a half period with respect to the period of the fringe constituting the hidden pattern around the hidden pattern 11, the sharpness when generating the hidden pattern can be improved.
[0029]
In FIG. 11, the light diffraction structure 4 is formed on the surface of the base 5 via an adhesive 45.
The light diffractive structure 4 is formed on a base film and adhered to the substrate as it is, or only the resin of the light diffractive structure formed in a thin curtain is transferred to a printed matter by a thermal transfer method or the like. There may be.
When discriminating a hidden pattern incorporated in the light diffraction structure, when the discriminating tool 6 is brought close to the target substrate 5 at a predetermined angle, the hidden pattern is displayed on the discriminating tool 6 in a moire pattern. When the hidden pattern displayed on the determination tool 6 is a predetermined pattern, it is determined that the target substrate is a legitimate target (genuine) supplied from a correct supplier.
Since the light irradiated to the hidden pattern of the base 5 has to pass through the discriminator 6 and reach the visual means 7 of the observer, the discriminator is made of a transparent base substrate. Further, since the discriminating tool is frequently used, a discriminating tool in which a base substrate is fixed with a strong frame material (not shown) is often used.
A handle or the like can be attached to the frame material, thereby preventing the transparent base substrate of the discriminator 6 from being stained with fingerprints or oil.
[0030]
At the time of discrimination of the hidden pattern, the hidden pattern discriminating tool 6 is discriminated so as to be brought into close contact with the substrate 5 on which the light diffraction structure 4 is formed.
The hidden pattern can be discriminated from the close contact state up to a certain distance, but since the moire phenomenon is used, it is difficult to discriminate if the distance between the light diffraction structure 4 and the discriminator 6 is too large. .
Further, the light that generates the discrimination pattern by the hidden pattern (4) and the discrimination tool 6 becomes light incident from the direction of the visual means 7 shown in FIG. The material preferably has high transparency, and is formed so as not to interfere with the incident light by the discrimination pattern formed on the base material.
[0031]
Various embodiments of the discrimination pattern will be described with reference to FIG.
The discrimination pattern of e, f, g, and h formed on the surface of the transparent substrate is brought close to the surface of the hidden pattern, and a discrimination image based on the hidden pattern is generated.
FIG. 12E shows a discrimination pattern using a line having a stripe angle 65 of 45 ° with respect to the horizontal line. The lines are connected in pairs with transparent bands and colored bands. The width of the transparent band and the width of the colored band may be the same or different.
As described above, since the light for discriminating the hidden pattern is light that has passed through the discriminator, the light that is formed on the discriminator is narrower than the width of the transparent belt and more light is emitted. Try to get in. In addition, when the discrimination pattern is formed by printing or etching, a bright material, a transparent dye, or a transparent material can be used for the colored portion.
[0032]
FIG. 12F shows a discrimination pattern using a line with a stripe angle 66 of 135 ° with respect to the horizontal line. The contents of the discrimination pattern are based on the e diagram.
[0033]
FIG. 12G is a discrimination pattern by a diffraction grating having a stripe angle 67 of 45 ° with respect to the horizontal line.
[0034]
FIG. 12 h shows a discrimination pattern using halftone dots having a stripe angle 68 of 135 ° with respect to the horizontal line.
The halftone dot is composed of a point where the transparent part and the colored part are independent, or a point where the two parts are connected in a chain, and the (dotted) line connecting the transparent part is colored. A pair of (chain-like) lines connecting the parts is formed. This pair of bands is formed at an angle of 135 °. The configuration of the halftone dots and the transparent portion is the same as that in FIG.
[0035]
FIG. 13 is a cross-sectional view taken along line AA of the discriminator 6 shown in FIG.
In the discriminating tool, a transparent adhesive layer 63 and a light diffraction structure layer 62 are formed on the surface of a transparent substrate 64 made of synthetic resin or the like. The light diffractive structure layer 62 may be a line or halftone dot by etching or printing. A transparent reflective layer may be provided on the adhesive side of the light diffraction structure layer 62. A protective layer 61 is provided on the outermost surface of the optical diffraction structure layer 62 to protect the optical diffraction structure from abrasion.
As a material configuration, for example, the transparent substrate 64 is made of a plastic such as 100 to 250 μm polyethylene terephthalate (hereinafter referred to as polyester) and acrylic, and is preliminarily provided via a vinyl acetate or acrylic thermoplastic adhesive. The light diffraction structure coated with the protective layer 61 of acrylic resin is transferred by heat.
[0036]
(Example)
A thin metal-deposited glass plate is irradiated with an electron beam having a diameter of 4 microns to form a structural unit of a diffraction grating of 12 μ × 24 μ at an angle of 0 ° with respect to one cut surface of the glass.
The formation density of the constitutional units was 3 rows / band, and was formed at a pitch of 0.5 constitutional units in the longitudinal direction of the band. The bands on the connecting side were formed by changing the diffraction angle, and two bands were alternately formed. As a result, the stripe density was set to 7 stripes / mm.
Patterns that can be discriminated from masking patterns and patterns that are difficult to discriminate were produced, and incorporated as part of the design of the entire diffraction grating.
Duplicate plates were prepared from this original plate, and irregularities were reproduced on the surface of a transparent acrylic resin applied on the base film to prepare a light diffraction structure. A yellow colorant was applied to the transparent resin on the base film on which the light diffractive structure was replicated, and an aluminum thin film was formed thereon by vacuum deposition, and a heat-sensitive adhesive was applied thereon.
The light diffraction structure formed on the base film was thermally transferred to a sample of a high-quality paper gift voucher with a line drawing printed on the surface by a metal plate heated to 160 degrees Celsius.
As a result of observing the light diffraction structure at a position where the design of the gift voucher looks correct and visually recognizing a pattern that is difficult to discriminate as a hidden pattern, it cannot be discriminated by ordinary visual means. It was possible to distinguish clearly.
[0037]
【The invention's effect】
The following effects can be obtained by the hidden pattern of the light diffraction structure of the present invention.
1) As in the first and second aspects of the invention, an optical diffraction structure including a pattern (hidden pattern) difficult to discriminate by a diffraction grating formed on a flat portion of a substrate and a discriminable pattern,
The difficult-to-discriminate pattern and the discriminable pattern are formed of stripes in which either a pair of two band pairs or a pair of two dot pairs are regularly arranged, It is difficult to discriminate hidden patterns by forming pairs or bands or dots with different diffraction gratings, and forming difficult patterns by covering part of the distinguishable patterns. Even if it is determined, it is possible to make it difficult to duplicate the next step.
2) As in the invention according to claim 3, in the invention according to any one of claims 1 to 2, the diffraction grating formed on one band of stripes or one of the plurality of dots is The difference between at least one of the pitch and diffraction angle of the diffraction grating formed on the band or adjacent dots is different in the color of the two stripes, making it difficult to confirm the hidden pattern in a normal viewing state. It becomes possible.
3) Like invention of Claim 4, in invention of any one of Claims 1-3, when the width | variety of a fringe is 0.2 mm or less, it is the band of the zone | band by the diffraction grating which comprises a fringe. The thickness is 100 μm or less, and even if there is a difference in the color of each stripe, since the band per stripe and the thickness of the stripe are fine, it looks like a uniform diffraction image in a normal viewing state, The presence of the hidden pattern can be made more difficult to confirm.
4) As in the invention according to claim 5, in the invention according to any one of claims 1 to 4, the dot width is a pattern of stripes formed by bands by approximating the width of the bands And it becomes difficult to distinguish.
5) A discriminator for discriminating a hidden pattern by the light diffraction structure according to any one of claims 1 to 5 as in the invention according to claim 6, wherein either a pattern capable of discriminating parallel straight lines or a pattern difficult to discriminate Since the pattern is formed on the transparent substrate at a pitch approximate to the pitch of the stripes of one pattern, the discrimination can be easily performed.
[Brief description of the drawings]
FIG. 1 is a view for explaining an example of a printed material on which a light diffraction structure having a hidden pattern of the present invention is transferred and its discriminating tool.
FIG. 2 is a diagram for explaining an embodiment in which a hidden pattern is generated by a discriminator.
FIG. 3 is an enlarged view of a part of the entire area of FIG. 1;
4 is an enlarged schematic diagram of a partial region of FIG. 3;
FIG. 5 is a diagram for explaining an example of a diffraction angle and a built-in angle of the partial region shown in FIG. 4;
FIG. 6 is a diagram for explaining an aggregate of two bands forming a pair.
FIG. 7 is a diagram for explaining fringe density.
FIG. 8 is a diagram for explaining an embodiment of a diffraction grating formed in a band.
FIG. 9 is a diagram for explaining an embodiment of dots.
FIG. 10 is an embodiment of a border.
FIG. 11 is a diagram for explaining a state in which a hidden pattern is discriminated by a discriminator.
FIG. 12 is a diagram for explaining an embodiment of a discrimination pattern.
13 is a cross-sectional view taken along line AA in FIG.
[Explanation of symbols]
1,11 Difficult patterns (hidden patterns)
2 Background patterns 3-1 and 3-2 Discriminated patterns (visible patterns)
4 Whole area (light diffraction structure)
5 Substrate (printed material)
6 Discriminator 7 Visual Means 10 Border 45 Adhesive 61 Protective Coat Layer 62 Light Diffraction Structure Layer 63 Adhesive Layer 64 Substrate 65, 66, 67, 68 Discrimination Pattern Formation Angle 120 Hidden Pattern 200 Background Pattern 320 Visible Pattern 321 Visible Pattern Partial pattern 1200, 1300 Band 1400 Stripe (one pair of bands)
2100,2200 dot strips

Claims (6)

An optical diffraction structure including a pattern (hidden pattern) difficult to distinguish by a diffraction grating formed on a flat portion of a substrate and a distinguishable pattern,
The difficult-to-discriminate pattern and the discriminable pattern are formed of stripes in which either a pair of two band pairs or a pair of two dot pairs are regularly arranged , optical diffraction structure is strip or dot pairs, characterized in that formed in different diffraction grating with each other. The determination difficult patterns, optical diffraction structure according to claim 1, characterized in that it is formed so as to cover a part of the distinguishable pattern. The diffraction grating formed on one band of the stripes or one of the plurality of dots is different from the diffraction grating formed on the other band or adjacent dots in at least one of pitch and diffraction angle. optical diffraction structure according to any one of claims 1-2, characterized. The width of the stripes, the light diffraction structure according to claim 1 any one, characterized in that it is 0.2mm or less. The width of the dots, the optical diffraction structure according to any one of claims 1 to 4, characterized in that an approximation to the width of the band. 6. A discriminating tool for discriminating a hidden pattern by the light diffraction structure according to claim 1, wherein the stripe pitch and the approximate pitch of any one of a pattern capable of discriminating parallel straight lines and a pattern difficult to discriminate A hidden pattern discriminating tool using a light diffraction structure, which is formed on a transparent substrate.

Images