JP6579418B2 - Code pattern authentication method and authentication apparatus - Google Patents

Description

  The present invention relates to an authentication method and an authentication apparatus for authenticating a code pattern attached to a laminate or a box.

  In recent years, several techniques for discriminating an object accommodated in a container in a non-contact and non-opening manner have been proposed. For example, in Patent Document 1, a predetermined image is formed inside the container, and the image is read unopened by irradiating infrared rays toward the image from the outside of the container. It has been proposed to discriminate objects.

  However, since infrared rays do not transmit thick paper such as cardboard or resin, when an image is provided inside a container such as an envelope made of thick paper or resin, the image cannot be read using infrared rays. In consideration of such problems, for example, Patent Documents 2 and 3 propose using terahertz waves. Terahertz waves have the property that they can penetrate many packaging materials such as paper and resin. Therefore, if terahertz waves are used, information about the object stored in the container made of paper or resin can be obtained in a non-contact and non-opening manner.

JP 2001-96889 A JP 2013-178212 A JP 2010-145391 A

  In the above-described Patent Documents 2 and 3, the object is determined based on the terahertz wave transmitted or reflected by the object. Specifically, the target is discriminated based on spectral information unique to the target that appears in the terahertz wave transmitted or reflected by the target. However, depending on the object, characteristic frequency dependence may not appear within the frequency range of the terahertz wave. In addition, when the object is an object such as a vegetable having a large individual difference, it can be considered that the spectrum information varies greatly even if the object is the same kind. Therefore, it is considered that the object cannot be determined with high accuracy depending on the spectrum information unique to the object.

  Further, when discriminating an object based on spectrum information unique to the object, a step of collating the acquired spectrum information with characteristic spectrum information of various objects recorded in advance is performed. The In this case, it is necessary to prepare in advance a lot of spectrum information having an enormous amount of data, and the number of man-hours required for collation increases.

  Further, Patent Document 2 proposes that an information code is provided on the surface of the container, and further information regarding the object is obtained by reading this information code using terahertz waves. Specifically, it has been proposed to obtain character information by reading the shape of an information code composed of a predetermined character string using terahertz waves. However, the shape of characters is complicated and the types of characters are enormous. Therefore, in the method of obtaining information based on the shape of the information code, it is considered that erroneous recognition can easily occur when noise exists. In addition, it is necessary to prepare in advance information on a huge amount of data related to the character shape, and the number of man-hours required for collation increases.

  The present invention has been made in consideration of such points, and an object thereof is to provide an authentication method and an authentication apparatus using a code pattern that can be easily analyzed.

  The present invention provides an irradiation step of irradiating an electromagnetic wave to a code pattern including at least a first region including a plurality of first elements arranged regularly, and the electromagnetic wave transmitted through the code pattern or reflected by the code pattern. A measurement step of measuring the frequency spectrum of the electromagnetic wave, and an analysis step of analyzing the code pattern based on a result of the measurement step, wherein each first element is configured as a conductive pattern having conductivity. Or an opening pattern formed in a conductive layer having conductivity, and the width of each first element in the first region or the interval between the first elements is at least partially, The frequency spectrum is smaller than the wavelength of the electromagnetic wave, and the frequency spectrum is transmitted through the first region or before being reflected by the first region. Code pattern authentication, including a first frequency spectrum of electromagnetic waves, wherein in the analyzing step, the code pattern is analyzed based on a frequency at which a feature point appears in the first frequency spectrum or a first derivative of the first frequency spectrum Is the method.

  In the code pattern authentication method according to the present invention, the code pattern may further include a second region including a plurality of second elements regularly arranged. In this case, each 2nd element is comprised as an electroconductive pattern which has electroconductivity, or is comprised as an opening pattern formed in the electroconductive layer which has electroconductivity, Each 2nd element of the said 2nd area | region Or the spacing between the second elements is at least partially smaller than the wavelength of the electromagnetic wave and is different from the width of the first elements in the first region or the spacing between the first elements, The frequency spectrum further includes a second frequency spectrum of the electromagnetic wave transmitted through the second region or the electromagnetic wave reflected by the second region, and in the analyzing step, the code pattern includes each frequency spectrum or each frequency. Analysis is based on the frequency at which feature points appear in the first derivative of the spectrum.

  In the irradiation step of the code pattern authentication method according to the present invention, an electromagnetic wave within a wavelength range of 100 μm to 3 mm is used as the electromagnetic wave, and the code pattern is shielded from the outside by an opaque layer made of paper or an opaque resin. It may be provided in a different place. In this case, in the irradiation step, the electromagnetic wave passes through the opaque layer and reaches the code pattern.

  In the code pattern authentication method according to the present invention, the code pattern may be provided in a place other than the outer surface of the container in the container including an opaque layer made of paper or opaque resin. Moreover, the target object may be accommodated in the said accommodating body. In this case, the object may be determined based on the analysis result of the code pattern.

  In the irradiation step of the code pattern authentication method according to the present invention, an electromagnetic wave generated by utilizing a nonlinear optical effect generated by irradiating a nonlinear optical crystal with laser light may be used as the electromagnetic wave.

  In the irradiation step of the code pattern authentication method according to the present invention, the spot irradiated with the electromagnetic wave in the code pattern is scanned along the direction in which the first region and the second region are arranged, The first frequency spectrum and the second frequency spectrum may be measured sequentially.

  In the irradiation step of the code pattern authentication method according to the present invention, the spot irradiated with the electromagnetic wave in the code pattern may at least partially include both the first region and the second region. In this case, in the measurement step, both the first frequency spectrum and the second frequency spectrum are measured simultaneously.

  The present invention includes an irradiation unit that irradiates a code pattern electromagnetic wave including at least a first region that is regularly arranged and includes a plurality of first elements having conductivity, and the electromagnetic wave that transmits the code pattern, or the code A measurement unit that measures a frequency spectrum of the electromagnetic wave reflected by the pattern, and an analysis unit that analyzes the code pattern based on a measurement result in the measurement unit, and each of the first elements of the first region The width or spacing between each first element is at least partially smaller than the wavelength of the electromagnetic wave, and the frequency spectrum is transmitted through the first region, or the electromagnetic wave reflected by the first region. In the analysis unit, the code pattern includes the first frequency spectrum or the first frequency spectrum. Are analyzed based on the frequency characteristic point appears on first-order derivative of the frequency spectrum, the authentication apparatus of the code pattern.

  In the present invention, the code pattern includes at least a first region including a plurality of regularly arranged first elements. The width of each first element in the first region or the interval between the first elements is smaller than the wavelength of the electromagnetic wave applied to the code pattern. Therefore, the first frequency spectrum of the electromagnetic wave transmitted through the first region or the electromagnetic wave reflected by the first region is based on the width of each first element in the first region or the interval between the first elements. A first feature point appears. Therefore, desired information can be given to the code pattern by appropriately setting the width of each first element in the first region or the interval between the first elements. Further, by analyzing the first frequency spectrum of the first region constituting the code pattern, the information included in the code pattern can be easily obtained.

It is a top view which shows the structure of the container which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the AA cross section of the container of FIG. It is a top view which expands and shows each area | region of a code pattern. It is a figure which shows schematic structure of the authentication apparatus which concerns on embodiment of this invention. It is a figure which shows the irradiation process which irradiates electromagnetic waves to a code | cord pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves reflected from the code pattern. It is a figure which shows an example of the first derivative of the frequency spectrum of the electromagnetic waves reflected from the code pattern. It is a figure which shows schematic structure of the authentication apparatus which concerns on the modification of embodiment of this invention. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 9A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 10A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 11A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 12A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 13A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 14A. It is a top view which shows one modification of a code pattern. It is a figure which shows an example of the frequency spectrum of the electromagnetic waves which permeate | transmitted the code pattern of FIG. 15A. It is a top view which shows one modification of a code pattern. It is sectional drawing which shows the modification of a structure of a container. It is sectional drawing which shows the example in which a code pattern is provided in a laminated body. It is a figure which shows the frequency spectrum of the electromagnetic waves reflected from the code pattern by an Example. It is a figure which shows the result of having plotted the feature point of the frequency spectrum of the electromagnetic wave reflected from the code pattern by an Example with respect to the total value of the width | variety of the element of each area | region of a code pattern, and each element.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual product.

  In the present embodiment, an example will be described in which an object is accommodated in a container and a code pattern in which information about the object is recorded is provided in the container. FIG. 1 is a plan view showing the configuration of the container 100. FIG. 2 is a cross-sectional view showing the configuration of the AA cross section of the container 100 of FIG.

Storage Unit As shown in FIG. 1, the storage body 100 includes a storage body main body 10 that stores an object and a cord pattern 20. The container body 10 includes an opaque layer made of paper or opaque resin. For this reason, visible light and infrared rays are reflected or absorbed by the container body 10. That is, visible light and infrared rays cannot pass through the container body 10. Therefore, the object cannot be visually recognized from the outside of the container body 10. Note that “reflect or absorb infrared rays” means that when the container body 10 is irradiated with infrared rays, the infrared rays do not pass through the container body 10 at all, and even if infrared rays pass through the container body 10, This means that the amount of transmitted light is so small that the transmitted infrared light cannot be detected by the sensor.

  As the paper constituting the container body 10, for example, cardboard is used. The container 100 may be a cardboard envelope. In this case, the container body 10 has an envelope shape, and includes an envelope portion 11 and a flap portion (margin) 12 provided at an opening of the envelope portion 11. The flap part 12 is folded back 180 ° and adhered to the adhesive region 11a of the envelope part 11, whereby the container 100, which is a cardboard envelope, is sealed. FIG. 1 shows the container 100 before the flap 12 is folded back.

  As shown in FIG. 2, the container body 10 includes a first layer 13 that is a cardboard, and a second layer 14 and a third layer 15 that are stacked on the first layer 13. . Of the two surfaces facing outward of the first layer 13 formed in an envelope shape, the second layer 14 is laminated and bonded to one surface, and the third layer 15 is laminated to the other surface. It is glued.

  The code pattern 20 is provided at a location shielded from the outside by an opaque layer made of paper or opaque resin. When the code pattern 20 is provided in the container 100, the code pattern 20 is provided in a place other than the outer surface 10 x of the container body 10 in the container 100. In the example shown in FIG. 2, the code pattern 20 is provided between the first layer 13 and the second layer 14. The outer surface 10x is a surface that faces the outer side of the container body 10 when the container body 10 is sealed, that is, a surface that can be visually recognized by the naked eye.

Code pattern will be described below code pattern 20 in more detail. The code pattern 20 includes a plurality of areas in which predetermined information is recorded. For example, as shown in FIG. 1, the code pattern 20 includes a first region 21 including first information, a second region 22 including second information, and a third region 23 including third information. . Each information is derived through a measurement process and an analysis process described later. The type of information included in each of the areas 21, 22, and 23 is not particularly limited. For example, the first information, the second information, and the third information may be numeric information “1”, “2”, and “3”, respectively. In this case, the code pattern 20 can express a predetermined numeric string according to the arrangement of the areas 21, 22, and 23. For example, in FIG. 1, the first area 21, the second area 22, the third area 23, and the second area 22 are arranged in order from the left, so that the code pattern 20 represents a number string “1232”. Can do.

(Cross-sectional structure of code pattern)
Next, the cross-sectional structure of the code pattern 20 will be described with reference to FIG. In each of the areas 21, 22, and 23 of the code pattern 20, only the widths of elements and intervals between elements described later are different, and the cross-sectional structures of the areas 21, 22, and 23 are the same. In FIG. 2, a cross-sectional structure common to the regions 21, 22, and 23 is shown.

  In the present embodiment, as will be described later, an electromagnetic wave having a frequency range of 0.1 THz to 3 THz is used in the authentication process of the code pattern 20. In the following description, an electromagnetic wave having a frequency range of 0.1 THz to 3 THz is also referred to as a terahertz wave. If the terahertz wave is expressed in the wavelength range assuming that the speed of the electromagnetic wave is 300,000 kilometers per second, it can be said that the terahertz wave is an electromagnetic wave in a wavelength range of 100 μm to 3 mm. The code pattern 20 is formed of a material that can reflect or absorb the terahertz wave. For example, as shown in FIG. 2, the code pattern 20 is formed by patterning a conductive layer 25 having conductivity. In FIG. 2, a conductive pattern formed by patterning the conductive layer 25 is denoted by reference numeral 26. An opening pattern formed in the conductive layer 25 is represented by reference numeral 27. The “opening pattern 27” is a pattern of openings formed in the conductive layer 25. In other words, the “opening pattern 27” is a pattern of a region sandwiched between the conductive patterns 26.

  The material constituting the conductive layer 25 is not particularly limited as long as it has conductivity and can reflect or absorb terahertz waves. For example, various metal materials, conductive materials such as carbon, composite materials obtained by combining two or more conductive materials, and the like can be used as the material constituting the conductive layer 25. As a specific example, the conductive layer 25 can be formed using a chromium thin film. The thickness of the conductive layer 25 is set within a range of 50 nm to 5 μm, for example.

As will be described later, the width of the elements of each region 21, 22, 23 formed by the conductive pattern 26 or the opening pattern 27 or the spacing between the elements is at least partly a terahertz wave used in the authentication method of the code pattern 20. It is set to be smaller than the wavelength. As long as such conditions can be realized, the method for forming the conductive pattern 26 and the opening pattern 27 is not particularly limited.
For example, first, the conductive layer 25 containing a conductive material such as chromium is continuously provided by using a sputtering method, a vacuum deposition method, an ion plating method, a CVD method, a coating method, a printing method, or the like. Next, a resist pattern having the same pattern as the conductive pattern 26 is formed on the conductive layer 25, and then the conductive layer 25 is etched. Thereby, the conductive pattern 26 and the opening pattern 27 can be produced. That is, the conductive pattern 26 and the opening pattern 27 can be obtained by patterning the conductive layer 25 using a so-called photolithography method. According to the photolithography method, a pattern can be formed with micrometer accuracy, and therefore the conductive pattern 26 and the opening pattern 27 having a width smaller than the wavelength of the terahertz wave can be easily obtained with high accuracy.
Alternatively, the material constituting the conductive layer 25 is formed using a sputtering method, a vacuum deposition method, an ion plating method, or the like through a mask plate having an opening formed in the same pattern as the conductive pattern 26. To do. Thereby, the conductive pattern 26 and the opening pattern 27 can also be produced.

  In the example shown in FIG. 2, the code pattern 20 is directly formed on the first layer 13 of the container 100, but is not limited thereto. For example, first, the conductive layer 25 is formed on a suitable base material, and then the conductive layer 25 is patterned using a photolithography method to produce the code pattern 20, and then the base on which the code pattern 20 is formed. The cord pattern 20 may be provided on the container 100 by attaching the material to the container 100 using an adhesive or the like.

  Other patterning methods may be employed as long as the width of the conductive pattern 26 and the opening pattern 27 can be made smaller than the wavelength of the terahertz wave. For example, the conductive pattern 26 and the opening pattern 27 may be produced by applying a conductive ink containing granular carbon black or granular metal in a predetermined pattern using an inkjet method.

(Code pattern pattern shape)
Next, a pattern shape of the code pattern 20 will be described with reference to FIGS. 3 (a), 3 (b) and 3 (c) are enlarged plan views showing the first region 21, the second region 22, and the third region 23, respectively.

  As shown in FIG. 3A, the first region 21 includes a plurality of first elements 21a arranged regularly. The first elements 21a have a quadrangular shape, and the first elements 21a are arranged in a square lattice pattern. In FIG. 3A, the width of the first element 21a is represented by the symbol W1, and the interval between the first elements 21a is represented by the symbol G1.

  3B and 3C, the second region 22 includes a plurality of second elements 22a that are regularly arranged, and the third region 23 is regularly arranged. The plurality of third elements 23a are included. The shape and arrangement of the second element 22a and the third element 23a are the same as the shape and arrangement of the first element 21a except that the specific width and interval are different. In FIG. 3B and FIG. 3C, the widths of the second element 22a and the third element 23a are represented by symbols W2 and W3, and the interval between the second elements 22a and the distance between the third elements 23a. Are represented by reference numerals G2 and G3.

  Next, the width and interval of each element 21a, 22a, 23a will be described. In the present embodiment, each of the regions 21, 22, and 23 has a width W1 to W3 of each element 21a, 22a, and 23a of each region 21, 22, and 23 or a gap G1 to G3 between each element 21a, 22a, and 23a. At least one of them is configured to be at least partially smaller than the wavelength of the terahertz wave used in the code pattern 20 authentication method described later. In this case, the dielectric constants and magnetic permeability of the regions 21, 22, and 23 with respect to the terahertz wave are negative values. That is, each area | region 21, 22, 23 functions as what is called a metamaterial. Since the metamaterial is described in, for example, Japanese Patent Application Laid-Open No. 2013-5044, detailed description thereof is omitted here.

  Next, the relationship between the width and spacing of each element 21a, 22a, 23a will be described. In the present embodiment, each of the regions 21, 22, and 23 includes at least one of the widths W1 to W3 of the elements 21a, 22a, and 23a or the intervals G1 to G3 between the elements 21a, 22a, and 23a. It is configured to be different. For example, in the example shown in FIGS. 3A to 3C, the gap G3 between the third elements 23a is smaller than the gap G1 between the first elements 21a. In addition, the width W2 of each second element 22a is smaller than the width W1 of the first element 21a and the width W3 of the third element 23a, and the interval G2 between the second elements 22a is the first width of each first element 21a. It is smaller than the gap G1 between the elements 21a and the gap G3 between the third elements 23a. In this case, each of the regions 21, 22, and 23 exhibits different frequency responsiveness to the terahertz wave based on the characteristics of the metamaterial. For example, the terahertz waves transmitted through the regions 21, 22, and 23, or the frequency spectra of the terahertz waves reflected by the regions 21, 22, and 23 have different feature points indicating the start of peak and attenuation. Will appear in frequency. Therefore, by analyzing the frequency spectrum obtained by irradiating the terahertz wave to the code pattern 20 and calculating the frequency at which the feature points appear, the types and arrangement of the regions 21, 22, and 23 included in the code pattern 20 are calculated. Can be derived. Accordingly, information recorded in the code pattern 20 can be obtained.

  3A to 3C show examples in which each element 21a, 22a, 23a is configured as a conductive pattern 26 having conductivity. However, the specific configurations of the elements 21a, 22a, and 23a are not particularly limited as long as different frequency responsiveness can be exhibited depending on the width and interval. For example, each element 21a, 22a, 23a may be configured as an opening pattern including openings formed in the conductive layer 25 having conductivity.

  Next, the operation and effect of the present embodiment having such a configuration will be described. Here, a method for authenticating the code pattern 20 provided in the container 100 and discriminating an object stored in the container 100 will be described.

Authentication Device First, an authentication device 50 for implementing an authentication method for authenticating the code pattern 20 will be described with reference to FIG. As illustrated in FIG. 4, the authentication device 50 includes an irradiation unit 51 that irradiates the terahertz wave L1 on the code pattern 20, a measurement unit 52 that measures the frequency spectrum of the terahertz wave L2 reflected by the code pattern 20, and a measurement unit. And an analysis unit 53 that analyzes the code pattern 20 based on the measurement result in 52. In addition, the irradiation part 51, the measurement part 52, and the analysis part 53 may be comprised integrally, and may be comprised separately.

  In the irradiation unit 51, a generation system using a photoconductive antenna or a semiconductor can be used as a generation system of electromagnetic waves composed of terahertz waves. In addition, as a generation system, a generation system that generates an electromagnetic wave using a nonlinear optical effect such as optical parametric or difference frequency mixing generated by irradiating a nonlinear optical crystal with laser light can be used. In addition, examples of the generation system include a quantum cascade laser (QCL), a resonant tunnel diode (RTD), a gyrotron, and a free electron laser (FEL).

Among these, a generation system that generates electromagnetic waves composed of terahertz waves using nonlinear optical effects such as optical parametric and difference frequency mixing can generate terahertz waves having high intensity. For example, a terahertz wave having an intensity of 300 mW or more or an intensity of 1 W or more can be generated. For this reason, even when a layer having a large thickness is used as the opaque layer of the container 100, the electromagnetic wave returning from the container 100 can be detected with sufficient accuracy. For example, when a generation system that generates electromagnetic waves using nonlinear optical effects such as optical parametric and difference frequency mixing is used, paper having a thickness in the range of 100 μm to 1 cm may be used as the paper constituting the opaque layer. it can. As a result, the authentication method implemented by the authentication device 50 can be used over a wider field.
The nonlinear optical crystal is a crystal that responds nonlinearly, that is, not proportional to the electromagnetic field of light when intense light such as laser light is incident. The nonlinear optical effect is a nonlinear response, that is, a response that is not proportional to the electromagnetic field of light. The optical parametric and difference frequency mixing described above are a kind of nonlinear optical effect.

  As the measurement unit 52, a unit that can measure the intensity of the terahertz wave reflected by the code pattern 20 for each frequency to obtain a frequency spectrum is used. For example, a spectrum analyzer is used as the measurement unit 52.

Authentication Method Next, an authentication method for authenticating the code pattern 20 using the authentication device 50 will be described.

(Irradiation process)
First, an irradiation step of irradiating the code pattern 20 with electromagnetic waves from the outside of the container 100 is performed using the irradiation unit 51. As described above, since terahertz waves having a frequency range of 0.1 THz to 3 THz are used as electromagnetic waves, the electromagnetic waves can pass through the container body 10 and reach the code pattern 20. In order to further increase the transparency, an electromagnetic wave of 1 THz to 2 THz may be used.

  FIG. 5 is a diagram illustrating a state where the code pattern 20 is irradiated with electromagnetic waves. In FIG. 5, the spot of the electromagnetic wave applied to the first region 21 is represented by reference numeral 54. As shown in FIG. 5, the electromagnetic wave is adjusted so that the spot 54 straddles the plurality of first elements 21a. According to the present embodiment, since the terahertz wave having high directivity is used as the electromagnetic wave, the size of the spot 54 can be adjusted with high accuracy.

  The electromagnetic wave is irradiated onto the first region 21 and then scanned along the direction in which the regions 21, 22 and 23 are arranged, as indicated by arrows in FIG. 5. As a result, it is possible to sequentially irradiate the areas 21, 22, and 23 included in the code pattern 20 with electromagnetic waves. The method for scanning electromagnetic waves is not particularly limited. For example, the regions 21, 22, and 23 may be scanned with electromagnetic waves by moving the irradiation unit 51. Alternatively, as shown in FIG. 4, the container 100 is moved with respect to the irradiation unit 51 by placing the container 100 on the moving conveyance unit 55, and thereby each region 21, 22, 22. 23 may be scanned with electromagnetic waves. In addition, as for the space | interval between each area | region 21, 22, 23, the spot 54 straddles two several area | regions, As a result, the measurement result based on one area | region and the measurement result based on another area | region will be obtained simultaneously. It is set appropriately to suppress this.

(Measurement process)
Next, the measurement process of measuring the frequency spectrum of the electromagnetic wave reflected by the code pattern 20 using the measurement unit 52 is performed. As described above, when the regions 21, 22 and 23 are sequentially scanned by the electromagnetic waves, the frequency spectrum of the electromagnetic waves reflected by the regions 21, 22 and 23 can be obtained sequentially. In the following description, the frequency spectra of the electromagnetic waves reflected by the first region 21, the second region 22, and the third region 23 are referred to as a first frequency spectrum S1, a second frequency spectrum S2, and a third frequency spectrum S3, respectively.

  FIG. 6 is a diagram illustrating an example of each frequency spectrum S1, S2, S3. As shown in FIG. 6, in each frequency spectrum S1, S2, S3, the reflectance decreases at a predetermined ratio as the frequency increases in a predetermined frequency range, and before and after the predetermined frequency range, The reflectance is almost constant. In FIG. 6, points at which the reflectances of the frequency spectra S1, S2, and S3 start to decrease are indicated by reference characters P1, P2, and P3 as feature points, respectively. The frequencies at which the feature points P1, P2, and P3 appear are represented by symbols f1, f2, and f3.

  As shown in FIG. 6, the frequencies f1, f2, and f3 at which the characteristic points P1, P2, and P3 of the frequency spectra S1, S2, and S3 appear are different from each other. This difference is based on the width of each element 21a, 22a, 23a of each area | region 21, 22, 23, and the space | interval between each element 21a, 22a, 23a differing.

  In the example shown in FIG. 6, the lower limit of the frequency range in which the reflectance decreases is recognized as each feature point P1, P2, P3. However, as long as the characteristics of the frequency spectra S1, S2, and S3 are reflected, the points that are recognized as the characteristic points P1, P2, and P3 are not particularly limited. For example, as the feature points P1, P2, and P3, the upper limit of the frequency range in which the reflectance decreases may be recognized. Alternatively, a point in the frequency range where the reflectance decreases, for example, an intermediate point in the frequency range may be recognized as the feature points P1, P2, and P3.

Depending on the shape of each frequency spectrum S1, S2, S3, it may be difficult to identify the feature points P1, P2, P3. For example, the upper or lower limit of the frequency range in which the reflectance decreases or increases may become ambiguous due to the gradual slope of the decrease or increase in reflectance or the fact that the slope is not constant. On the other hand, depending on the shape of each frequency spectrum S1, S2, S3, a characteristic frequency value may appear prominently in the spectrum obtained by first-order differentiation of the frequency spectra S1, S2, S3. FIG. 7 is a diagram illustrating the first derivatives S1 ′, S2 ′, and S3 ′ of the frequency spectra S1, S2, and S3 when it is assumed that the slope of the decrease in reflectance in the frequency spectra S1, S2, and S3 is not constant. It is. In this case, as shown in FIG. 7, peaks appear in the first derivatives S1 ′, S2 ′, S3 ′ of the frequency spectra S1, S2, S3, respectively. Therefore, the points taking the extreme values of the peaks are recognized as the characteristic points P1 ′, P2 ′, P3 ′ of the first derivatives S1 ′, S2 ′, S3 ′ of the frequency spectra S1, S2, S3, and the characteristic point P1 By calculating the frequencies f1 ', f2', and f3 'at which', P2 ', and P3' appear, the characteristics of the frequency spectra S1, S2, and S3 can be grasped more easily and accurately.
Although not shown, the characteristics of the frequency spectra S1, S2, and S3 may be grasped based on higher-order differentiation of the frequency spectra S1, S2, and S3.

(Analysis process)
Next, an analysis process for analyzing the code pattern 20 based on the result of the measurement process is performed. Specifically, the code pattern 20 is analyzed based on the above-described frequencies f1, f2, and f3 obtained based on the frequency spectra S1, S2, and S3. Note that the following analysis of the code pattern 20 may be performed based on the above-described frequencies f1 ′, f2 ′, and f3 ′.

  As is apparent from FIG. 5, in the measurement unit 52, the first frequency spectrum S1 having the feature point P1 at the frequency f1, the second frequency spectrum S2 having the feature point P2 at the frequency f2, and the first feature point having the feature point at the frequency f3. A three-frequency spectrum S3 and a second frequency spectrum S2 having feature points at the frequency f2 are obtained in sequence. The analysis unit 53 records in advance information that the frequencies at which the characteristic points P1, P2, and P3 of the frequency spectra S1, S2, and S3 appear are frequencies f1, f2, and f3, respectively. Therefore, the analysis unit 53 includes the first region 21, the second region 22, the third region 23, and the second region in which the code patterns 20 are sequentially arranged from the upstream side in the scan direction of the electromagnetic wave based on the measurement result in the measurement unit 52. It can be derived that the region 22 is included.

  Further, as described above, when the pieces of numerical information “1”, “2”, and “3” are assigned to the areas 21, 22, and 23, the analysis unit 53 indicates that the code pattern 20 has the numerical value “1232”. It can be authenticated that it is a column. Moreover, various discrimination | determination of the target object accommodated in the container 100 or the container 100 can be performed based on the numerical string etc. which are obtained in this way. For example, it is possible to determine whether or not the object is stored in an appropriate container 100, whether the container 100 is authentic, or the like.

  Here, according to the present embodiment, as described above, the frequency spectrums S1, S2, S3 reflected by the areas 21, 22, 23 on the information included in the areas 21, 22, 23 of the code pattern 20 are reflected. Can be obtained based on the feature points P1, P2, and P3. As described above, the feature points P1, P2, and P3 are identified as points at which the decrease or increase in the frequency spectrum starts or ends and points at which the frequency spectrum peaks appear. Therefore, the feature points P1, P2, and P3 can be easily calculated based on visual observation or simple data processing. In addition, by assigning predetermined numbers and characters to the feature points P1, P2, and P3, information such as character strings and number strings can be easily authenticated. For this reason, according to the present embodiment, the information given to the code pattern 20 can be reduced with less man-hours than in the case of the above-mentioned Patent Documents 2 and 3 that require precise collation with information recorded in advance. Can be easily obtained.

  Further, according to the present embodiment, the frequency at which the characteristic points P1, P2, and P3 of each frequency spectrum S1, S2, and S3 appear is the width of each element 21a, 22a, and 23a of each region 21, 22, and 23 and each element. It is determined based on the interval between 21a, 22a and 23a. For this reason, by appropriately setting the difference in width and interval, a frequency spectrum having a predetermined feature point is erroneously recognized as a frequency spectrum having other feature points in the analysis process. Can be prevented. Therefore, the accuracy of authentication of the code pattern 20 can be arbitrarily adjusted according to the request. On the other hand, in the case of the above-mentioned Patent Documents 2 and 3, since information is obtained based on spectrum information unique to the object, adjustment as in the present embodiment cannot be performed. Thus, the present embodiment has an advantage over the prior art in terms of flexibility.

  Further, according to the present embodiment, as described above, the terahertz wave is used as the electromagnetic wave applied to the code pattern 20. For this reason, compared with the case where visible light and infrared rays are used, the value of the width | variety and space | interval of the element of each area | region 21,22,23 which comprise the code pattern 20 required in order to comprise a metamaterial becomes large. . For example, even if the widths and intervals of the elements of the areas 21, 22 and 23 constituting the code pattern 20 are on the order of micrometers, the areas 21, 22 and 23 can be formed as metamaterials. For this reason, the code pattern 20 including the regions 21, 22, and 23 configured as a metamaterial can be easily manufactured by using a general photolithography method or the like. Further, since the terahertz wave is used, the code pattern 20 can be authenticated even when the code pattern 20 is provided at a place shielded from the outside by an opaque layer made of paper or an opaque resin.

  Further, according to the present embodiment, information included in the code pattern 20 is authenticated based on the frequency characteristics of the code pattern 20 instead of the shape of the code pattern 20 itself. Therefore, even if noise exists, it is possible to suppress the erroneous authentication of the code pattern 20 from occurring. Further, various shapes can be given to the code pattern 20 regardless of the information included in the code pattern 20. For this reason, the designability of the code pattern 20 can be improved.

  Note that various modifications can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as in the above embodiment. A duplicate description is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

(Examples where transmitted electromagnetic waves are used)
In the above-described embodiment, the example in which the frequency spectrum of the electromagnetic wave reflected by each of the regions 21, 22 and 23 of the code pattern 20 is measured in the measurement process using the measurement unit 52 has been described. However, the present invention is not limited to this, and the frequency spectrum of the electromagnetic wave transmitted through each of the regions 21, 22 and 23 of the code pattern 20 may be measured in the measurement process. In this case, as shown in FIG. 8, the measurement unit 52 is arranged so as to detect the electromagnetic wave L <b> 2 that has passed through the container 100 provided with the code pattern 20. Further, in the analysis step, the code pattern 20 is authenticated based on the feature points appearing in the frequency spectrum of the electromagnetic waves that have passed through the areas 21, 22, and 23 of the code pattern 20.

(Modified code pattern)
Further, in the above-described embodiment, the example in which the elements 21a, 22a, and 23a of the regions 21, 22, and 23 of the code pattern 20 are configured as the rectangular conductive pattern 26 having conductivity is shown. However, it is not limited to this. As long as feature points depending on the widths and intervals of the elements 21a, 22a, and 23a appear in the frequency spectra S1, S2, and S3, as described below with reference to FIGS. , 22, 23 can employ various pattern shapes.

  In principle, the same type of pattern shape is employed in each of the regions 21, 22, and 23. For example, when a wire grid type pattern is employed as shown in FIG. 9A, each of the elements 21a, 22a, 23a of the regions 21, 22, 23 has a wire grid shape. In this case, in each of the regions 21, 22, and 23, only the element width and the interval between the elements are different. Therefore, in the following description, only the pattern shape of the first region 21 will be described, and description regarding the pattern shape of the second region 22 and the third region 23 will be omitted.

  Further, if the frequency spectrum of the electromagnetic wave transmitted through each of the regions 21, 22 and 23 and the frequency spectrum of the electromagnetic wave reflected by each of the regions 21, 22 and 23 are ignored by absorption in each of the regions 21, 22 and 23, They are in an inverted relationship. Therefore, in the following description, only the frequency spectrum of the electromagnetic wave transmitted through the first region 21 is shown as the frequency spectrum, and the presentation of the frequency spectrum of the electromagnetic wave reflected by the first region 21 is omitted.

[First Modification]
FIG. 9A is a plan view showing a first region 21 of a wire grid type, and FIG. 9B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 9A. As shown in FIG. 9A, the first region 21 includes a plurality of first elements 21a extending linearly. The first elements 21a are arranged along a direction orthogonal to the extending direction. The first element 21a is configured as a conductive pattern 26 having conductivity.

  In this modification, as shown in FIG. 9B, the frequency spectrum S1A related to the polarization A having the electric field E and the magnetic field H shown in FIG. 9A and the frequency spectrum S1B related to the polarization B are measured as the frequency spectrum. The polarized light A has an electric field E parallel to the direction in which each first element 21a extends, and a magnetic field H orthogonal to the direction in which each first element 21a extends. On the other hand, the polarized light B has a magnetic field H parallel to the direction in which each first element 21a extends, and an electric field E orthogonal to the direction in which each first element 21a extends.

  In the frequency spectra S1A and S1B, the transmittance starts to increase and decrease when the frequency becomes equal to or higher than a predetermined frequency. Therefore, the points where the transmittance starts to increase and decrease can be identified as the feature points P1A and P1B. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature points P1A and P1B appear.

[Second Modification]
FIG. 10A is a plan view showing a mesh-type first region 21, and FIG. 10B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 10A. As shown to FIG. 10A, the 1st area | region 21 contains the some 1st element 21a arrange | positioned so that a mesh-shaped pattern may be formed. The first element 21 a is configured as an opening pattern 27 formed in the conductive layer 25.

  As shown in FIG. 10B, in the frequency spectrum S1, the transmittance starts to decrease when the frequency becomes a predetermined frequency or higher. Therefore, the point where the transmittance starts to decrease can be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Third Modification]
FIG. 11A is a plan view showing a mesh-type first region 21, and FIG. 11B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 11A. As shown to FIG. 11A, the 1st area | region 21 contains the some 1st element 21a arrange | positioned so that a mesh-shaped pattern may be formed. The first element 21a is configured as a conductive pattern 26 having conductivity.

  As shown in FIG. 11B, in the frequency spectrum S1, the transmittance starts to decrease when the frequency becomes equal to or lower than a predetermined frequency. Therefore, the point where the transmittance starts to decrease can be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Fourth Modification]
12A is a plan view showing a triangular lattice type first region 21, and FIG. 12B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 12A. As shown in FIG. 12A, the first region 21 includes a plurality of circular first elements 21a arranged in a triangular lattice pattern. The first element 21a is configured as a conductive pattern 26 having conductivity.

  As shown in FIG. 12B, the frequency spectrum S1 has a negative peak. Therefore, the point where the peak takes the extreme value can be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Fifth Modification]
FIG. 13A is a plan view showing a triangular lattice type first region 21, and FIG. 13B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 13A. As shown in FIG. 13A, the first region 21 includes a plurality of circular first elements 21a arranged in a triangular lattice pattern. The first element 21 a is configured as an opening pattern 27 formed in the conductive layer 25.

  As shown in FIG. 13B, the frequency spectrum S1 has a positive peak. Therefore, the point where the peak takes the extreme value can be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Sixth Modification]
FIG. 14A is a plan view showing a split ring type first region 21, and FIG. 14B is a diagram showing an example of a frequency spectrum of an electromagnetic wave transmitted through the first region 21 shown in FIG. 14A. As shown in FIG. 14A, the first region 21 includes a plurality of regularly arranged first elements 21a having a shape obtained by dividing a ring in part. The first element 21a is configured as a conductive pattern 26 having conductivity.

  As shown in FIG. 14B, the frequency spectrum S1 has a first negative peak and a second negative peak appearing on a higher frequency side than the first negative peak. The first peak is larger than the second peak. In this case, the point at which the first peak takes an extreme value can be recognized as the feature point P1. Alternatively, the point where the second peak takes an extreme value may be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Seventh Modification]
FIG. 15A is a plan view showing the first region 21 of the split ring type, and FIG. 15B is a diagram showing an example of the frequency spectrum of the electromagnetic wave transmitted through the first region 21 shown in FIG. 15A. As shown in FIG. 15A, the first region 21 includes a plurality of regularly arranged first elements 21a having a shape obtained by dividing a ring in part. The first element 21 a is configured as an opening pattern 27 formed in the conductive layer 25.

  As shown in FIG. 15B, the frequency spectrum S1 has a first positive peak and a second positive peak that appears on a higher frequency side than the first positive peak. The first peak is larger than the second peak. In this case, the point at which the first peak takes an extreme value can be recognized as the feature point P1. Alternatively, the point where the second peak takes an extreme value may be recognized as the feature point P1. Further, the code pattern 20 can be authenticated based on the frequency f1 at which the feature point P1 appears.

[Eighth Modification]
As shown in FIG. 16, the first element 21a of the first region 21 includes a first ring 28a, a second ring 28b disposed inside the first ring 28a, a first ring 28a and a second ring 28b. And a connection portion 28c for connecting the two. In the example shown in FIG. 16, two connecting portions 28 c arranged to form an angle of 90 degrees are provided. However, the number and arrangement of the connection portions 28c are not particularly limited. For example, only one connection portion 28c may be provided. In addition, two connection portions 28c arranged to form an angle of 180 degrees may be provided.

  According to this modification, although not shown, the frequency spectrum of the electromagnetic wave transmitted through the first region 21 or the electromagnetic wave reflected by the first region 21 can have a plurality of positive peaks and negative peaks. For this reason, the feature point of a frequency spectrum can be recognized based on a peak. In addition, the number and position of the peaks can be changed by changing the number and arrangement of the connecting portions 28c. For this reason, the characteristic points of the frequency spectrum can be set arbitrarily and easily.

  In the example illustrated in FIG. 16, the first ring 28 a, the second ring 28 b, and the connection portion 28 c are configured as the conductive pattern 26, but the present invention is not limited to this. As in the case of the several modifications described above, the first ring 28 a, the second ring 28 b, and the connection portion 28 c may be configured as the opening pattern 27 formed in the conductive layer 25.

  The first element 21a may further include a circular pattern provided inside the second ring 28b. In this case, the connection portion 28c may extend so as to connect between the first ring 28a and the second ring 28b, or extend so as to connect between the circular pattern and the second ring 28b. May be. Further, the connecting portion 28c may extend through the second ring 28b so as to connect the first ring 28a and the circular pattern.

(Variation of the place where the code pattern is provided)
In the above-described embodiment, the example in which the code pattern 20 is provided in the laminated body constituting the container 100 has been described. However, the place where the code pattern 20 is provided is not particularly limited.

  For example, as shown in FIG. 17, the code pattern 20 may be provided on the inner surface 10 y of the container body 10. In this case, the container 100 may be composed of a single layer of paper or resin instead of a paper or resin laminate including the first layer 13 and the second layer 14.

  As shown in FIG. 18, the code pattern 20 may be provided inside a stacked body 600 including a first layer 61 and a second layer 62 made of paper or opaque resin. The laminated body 600 can be used as a hard cover of a book, for example. In this case, the code pattern 20 may include information related to the book.

  Further, in the above-described embodiment and each modification, the code pattern 20 is shown in an example where the code pattern 20 is provided at a location shielded from the outside by an opaque layer made of paper or opaque resin. However, the present invention is not limited to this. Absent. For example, the code pattern 20 may be provided in a place where it can be visually recognized from the outside. As described above, the information included in the code pattern 20 is authenticated based on the frequency characteristics of the code pattern 20 instead of the shape of the code pattern 20 itself. For this reason, various shapes can be given to the code pattern 20 regardless of the information included in the code pattern 20. Therefore, the code pattern 20 having high design properties can be provided in a place where it can be visually recognized from the outside. Further, since the shape of the code pattern 20 itself does not include information, even if the code pattern 20 is provided in a place where it can be visually recognized from the outside, the information included in the code pattern 20 It is not easily authenticated other than.

(Modification of irradiation process and measurement process)
In the above-described embodiment, the example in which the electromagnetic wave is scanned along the direction in which the regions 21, 22, and 23 are arranged in the irradiation process is described, but the present invention is not limited to this. For example, in the measurement process, the spot 54 irradiated with the electromagnetic wave in the code pattern 20 may straddle at least two regions of the regions 21, 22, and 23. For example, the spot 54 may at least partially include both the first region 21 and the second region 22. In this case, an electromagnetic wave transmitted through the first region 21 or an electromagnetic wave reflected by the first region 21 and an electromagnetic wave transmitted through the second region 22 or an electromagnetic wave reflected by the second region 22 are generated simultaneously. By measuring these electromagnetic waves simultaneously, the first frequency spectrum S1 based on the first region 21 and the second frequency spectrum S2 based on the second region 22 may be obtained simultaneously. In this case, as the measurement unit 52, a device that detects electromagnetic waves from a plurality of regions of the code pattern 20 in a planar shape with a reception system in which a plurality of receiving elements are arranged in an array may be used. For example, as the measurement unit 52, a hyperspectral camera that can obtain a frequency spectrum in each unit region obtained by finely dividing a region to be measured can be used. Thereby, the arrangement of each region included in the code pattern 20 can be recognized more quickly, and therefore the code pattern 20 can be authenticated more quickly.

(Other variations)
In the above-described embodiment and each modification, the code pattern 20 includes an example including three types of areas, that is, the first area 21, the second area 22, and the third area 23. However, the code pattern 20 The number of types of areas included in 20 is not particularly limited. For example, the code pattern 20 may be composed of a first area 21 including first information and a second area 22 including second information. Alternatively, the code pattern 20 may include a fourth region including the fourth information or a further region in addition to the regions 21, 22, and 23 described above.
Alternatively, the code pattern 20 may include only one type of information. For example, the code pattern 20 attached to the first box includes only the first area 21 including the first information, and the code pattern 20 attached to the second box includes only the second area 22 including the second information. May be included. Even in this case, based on the frequency spectrum obtained when each box is irradiated with terahertz waves, the first box with the code pattern 20 including the first information and the code pattern including the second information It is possible to easily discriminate between the second box marked with.

  In addition, although some modified examples with respect to the above-described embodiment have been described, naturally, a plurality of modified examples can be applied in combination as appropriate.

  EXAMPLES Next, although an Example demonstrates this invention further more concretely, this invention is not limited to description of a following example, unless the summary is exceeded.

  First, a PET film having a thickness of 50 μm was prepared, and then a hard coat layer was provided on both sides of the PET film. The hard coat layer is made of resin and is provided for the purpose of protecting the surface of the PET film and increasing the resistance to printing. The method for forming the hard coat layer is not particularly limited, but a coating method is employed here. Thereafter, an adhesive layer and a release layer were formed on the surface of one of the hard coat layers provided on both sides of the PET film by a coating method.

  Next, on the surface of the other hard coat layer provided on both sides of the PET film, chromium was formed by vacuum deposition using a square mesh metal mesh pattern as a mask plate. . Thus, a chromium code pattern 20 having a thickness of 0.1 μm including the regions 21, 22, and 23 having a plurality of quadrangular elements 21 a, 22 a, and 23 a arranged in a square lattice pattern was obtained. That is, a code label having a chromium code pattern 20 on the surface was produced. At this time, the width W1 of the first element 21a and the gap G1 between the first elements 21a were set to 185 μm and 75 μm. Further, the width W2 of the second element 22a and the gap G2 between the second elements 22a were set to 50 μm and 20 μm. The width W3 of the third element 23a and the gap G3 between the third elements 23a were set to 185 μm and 35 μm.

  Next, a code label from which the release layer was peeled was attached to the inside of a cardboard box having a thickness of 50 mm. The cardboard box was sealed so that the code label could not be visually recognized from the outside.

Then, terahertz waves were irradiated from the outside of the cardboard box toward the position where the code label was affixed. As the light source of the terahertz wave, a light injection type terahertz parametric light source that generates a terahertz wave using a nonlinear optical effect generated by irradiating the nonlinear optical crystal LiNbO _{3 with a} YAG laser beam was used. The frequency of the terahertz wave was 0.1 to 1 THz. The terahertz wave passed through the cardboard box and reached the code label. The terahertz waves reflected by the areas 21, 22, and 23 of the code pattern 20 of the code label are transmitted again through the cardboard box and reach the terahertz wave pyro detector installed outside the cardboard box. FIG. 19 shows frequency spectra S1, S2, and S3 of the terahertz wave measured by the terahertz wave pyro detector.

  In each frequency spectrum S1, S2, S3, the points where the reflectance starts to decrease were identified as the feature points P1, P2, P3. The frequencies f1, f2, and f3 at which the feature points P1, P2, and P3 appear were 540 GHz, 670 GHz, and 430 GHz, respectively. The frequencies f1, f2, and f3 are sufficiently separated from each other, so that the frequency spectra S1, S2, and S3 can be easily distinguished.

  The frequencies f1, f2, and f3 at which the characteristic points P1, P2, and P3 shown in FIG. 19 appear are defined as the widths of the elements 21a, 22a, and 23a in the areas 21, 22, and 23 of the code pattern 20 and the elements 21a, 22a, and 23a. The results plotted against the total value of the intervals are shown in FIG. As shown in FIG. 20, it was confirmed that the frequency at which the feature point appears and the total value of the element width and the interval are substantially proportional to each other.

DESCRIPTION OF SYMBOLS 10 Container body 10x Outer surface 10y Inner surface 11 Envelope part 12 Flap part 13,61 1st layer 14,62 2nd layer 15 3rd layer 20 Code pattern 21 1st area | region 21a 1st element 22 2nd area | region 22a 2nd element 23 3rd area | region 23a 3rd element 25 Conductive layer 26 Conductive pattern 27 Opening pattern 28a 1st circumference 28b 2nd circumference 28c Connection part 30 Shielding object 31 Paper 50 Authentication apparatus 51 Irradiation part 52 Measurement part 53 Spot 55 Conveyance part 100 Accommodation body

Claims (7)

Third region including regularly arranged a plurality of first region comprising a first element, regularly arranged a plurality of second regions and regularly arranged plurality of third element comprises a second element An irradiation step of irradiating an electromagnetic wave to a code pattern including at least,
A measurement step of measuring a frequency spectrum of the electromagnetic wave transmitted through the code pattern or the electromagnetic wave reflected by the code pattern;
An analysis step of analyzing the code pattern based on the result of the measurement step,
Each first element is configured as a conductive pattern having conductivity, or is configured as an opening pattern formed in a conductive layer having conductivity,
The width of each first element in the first region or the spacing between the first elements is at least partially smaller than the wavelength of the electromagnetic wave,
Each second element is configured as a conductive pattern having conductivity, or is configured as an opening pattern formed in a conductive layer having conductivity,
The width of each second element in the second region or the interval between the second elements is at least partially smaller than the wavelength of the electromagnetic wave, and the width of each first element in the first region or each second element. Unlike the spacing between one element,
Each third element is configured as a conductive pattern having conductivity, or is configured as an opening pattern formed in a conductive layer having conductivity.
The width of each third element in the third region or the interval between the third elements is at least partially smaller than the wavelength of the electromagnetic wave, and the width of each first element in the first region or each first element. Unlike the spacing between one element and the width of each second element in the second region or the spacing between each second element,
The frequency spectrum is reflected by the electromagnetic wave transmitted through the first region or the first frequency spectrum of the electromagnetic wave reflected by the first region and the electromagnetic wave transmitted through the second region or by the second region. The second frequency spectrum of the electromagnetic wave, and the electromagnetic wave transmitted through the third region, or the third frequency spectrum of the electromagnetic wave reflected by the third region ,
In the analysis step, the code pattern is analyzed based on a frequency at which a feature point appears in each frequency spectrum or a first derivative of each frequency spectrum,
The feature point is a point at which each frequency spectrum or the first derivative of each frequency spectrum starts to decrease or increase, or a point that takes an extreme value of a peak appearing in each frequency spectrum or the first derivative of each frequency spectrum,
A code pattern authentication method in which a frequency at which the feature point appears and a total value of widths and intervals of the first element, the second element, and the third element corresponding to the feature point have a linear function relationship . In the irradiation step, an electromagnetic wave within a wavelength range of 100 μm to 3 mm is used as the electromagnetic wave,
The code pattern is provided in a place shielded from the outside by an opaque layer made of paper or opaque resin,
The code pattern authentication method according to claim 1, wherein, in the irradiation step, the electromagnetic wave reaches the code pattern through the opaque layer. The code pattern is provided in a place other than the outer surface of the container among the container including an opaque layer made of paper or opaque resin,
An object is accommodated in the container,
The code pattern authentication method according to claim 2, wherein the object is discriminated based on an analysis result of the code pattern.   In the said irradiation process, the electromagnetic wave produced | generated using the nonlinear optical effect produced by irradiating a laser beam with respect to a nonlinear optical crystal is used as the said electromagnetic wave. Code pattern authentication method. In the irradiation step, a spot irradiated with the electromagnetic wave in the code pattern is scanned along a direction in which the first region, the second region, and the third region are arranged, and as a result, the first frequency The code pattern authentication method according to any one of claims 1 to 4, wherein a spectrum, the second frequency spectrum, and the third frequency spectrum are sequentially measured. In the irradiation step, the spot irradiated with the electromagnetic wave in the code pattern includes at least part of both the first region and the second region,
5. The code pattern authentication method according to claim 1, wherein in the measurement step, both the first frequency spectrum and the second frequency spectrum are measured simultaneously. Is the second region and regularly arranged comprising a plurality of second element having a first region comprising a plurality of first element, a conductive while being regularly arranged with a conductivity while being regularly arranged And an irradiating unit for irradiating the electromagnetic wave to the code pattern including at least a third region including a plurality of third elements having conductivity ;
A measurement unit that measures the frequency spectrum of the electromagnetic wave transmitted through the code pattern or the electromagnetic wave reflected by the code pattern;
An analysis unit that analyzes the code pattern based on a measurement result in the measurement unit,
The width of each first element in the first region or the spacing between the first elements is at least partially smaller than the wavelength of the electromagnetic wave,
The width of each second element in the second region or the interval between the second elements is at least partially smaller than the wavelength of the electromagnetic wave, and the width of each first element in the first region or each second element. Unlike the spacing between one element,
Each third element is configured as a conductive pattern having conductivity, or is configured as an opening pattern formed in a conductive layer having conductivity.
The width of each third element in the third region or the interval between the third elements is at least partially smaller than the wavelength of the electromagnetic wave, and the width of each first element in the first region or each first element. Unlike the spacing between one element and the width of each second element in the second region or the spacing between each second element,
The frequency spectrum is reflected by the electromagnetic wave transmitted through the first region or the first frequency spectrum of the electromagnetic wave reflected by the first region and the electromagnetic wave transmitted through the second region or by the second region. The second frequency spectrum of the electromagnetic wave, and the electromagnetic wave transmitted through the third region, or the third frequency spectrum of the electromagnetic wave reflected by the third region ,
In the analysis unit, the code pattern is analyzed based on a frequency at which a feature point appears in each frequency spectrum or a first derivative of each frequency spectrum,
The feature point is a point at which each frequency spectrum or the first derivative of each frequency spectrum starts to decrease or increase, or a point that takes an extreme value of a peak appearing in each frequency spectrum or the first derivative of each frequency spectrum,
A code pattern authentication apparatus in which a frequency at which the feature point appears and a total value of widths and intervals of the first element, the second element, and the third element corresponding to the feature point have a linear function relationship .