Code forming method and information code

Abstract

The hiding code (CdS) is an information code in which information is recorded by the arrangement of a bright color cell (Cew) and a dark color cell (Ceb). A code forming method for forming such a concealing code (CdS) on an imprinting member (BM) includes a light-emitting layer forming step and a laser imprinting step. In the light-emitting layer formation step, a light-emitting layer (50) including a formation range (CA) of the concealing code (CdS) is formed by applying a coating agent containing a reaction coating material that reacts with invisible light and emits light to the imprinting member (BM). In the laser imprinting step, the light emission function of the dark cells (Ceb) is weakened compared to the light emission function of the bright cells (Cew) by irradiating the light emission layer (50) with laser light at positions corresponding to the dark cells (Ceb).

Description

[0001] Cross - reference to related applications

[0002] This application claims the priority of Japanese Patent Application No. 2022 - 162552 filed in Japan on October 7, 2022, and the entire contents thereof are incorporated herein by reference. Technical field

[0003] The disclosure of this specification relates to a technology of information codes for recording information. Background art

[0004] Patent Document 1 discloses a printing method of printing a transparent two - dimensional code using a transparent toner that exhibits absorption characteristics for infrared light. This two - dimensional code is visible by irradiation with infrared light and can be read.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018 - 89840

[0006] In the two - dimensional code disclosed in Patent Document 1, the positions where the transparent toner is not printed become white cells due to reflection of infrared light. On the other hand, the positions where the transparent toner is printed become black cells due to absorption of infrared light. Photographing such a two - dimensional code requires a special reading device capable of detecting infrared light. As a result, it may be difficult to ensure the convenience of the information code. Summary of the invention

[0007] An object of the present disclosure is to provide an information code that can ensure convenience and a method for forming such an information code.

[0008] In order to achieve the above object, one aspect of the disclosure is a code formation method for forming an information code that records information through an arrangement of bright regions and dark regions. The method includes a step of forming a light - emitting layer including a formation range of the information code by applying a coating agent containing a reaction coating material that reacts with invisible light to emit light to a formation object, and a step of weakening the light - emitting function of the dark region compared to the bright region by irradiating the position corresponding to the dark region in the light - emitting layer with a laser.

[0009] Another aspect of the disclosure is an information code that records information through an arrangement of bright regions and dark regions, including: a light - emitting layer containing a reaction coating material that reacts with invisible light to emit light; a strong light - emitting part located at a position corresponding to the bright region in the light - emitting layer and emitting light by reacting with invisible light; and a weak light - emitting part located at a position corresponding to the dark region in the light - emitting layer, and the light - emitting function of the reaction coating material is weaker than that of the strong light - emitting part.

[0010] Among these methods, the light-emitting function at the position corresponding to the dark region in the light-emitting layer containing the reactive coating is weakened compared to the position corresponding to the bright region. Therefore, by irradiating with invisible light, an arrangement of dark regions and bright regions with different light-emitting intensities is revealed. Based on the above, since the reading of the information code does not require a special reading device, the convenience of the information code can be ensured.

[0011] In addition, the reference numbers in parentheses in the claims only represent an example of the correspondence with the specific configurations in the following embodiments, and do not impose any limitation on the technical scope. In addition, if the combination does not particularly cause interference, combinations of claims not explicitly stated in the claims can also be made. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a diagram showing a hidden code according to an embodiment of the present disclosure.

[0013] Figure 2 It is a diagram showing an overall view in the case of applying the traceability system together with an existing circulation management system.

[0014] Figure 3 It is a detailed flowchart showing the code formation process for forming a hidden code.

[0015] Figure 4 It is a detailed diagram showing a transmittance test of a structure for explaining the weakening of the light-emitting function due to laser irradiation.

[0016] Figure 5 It is a diagram showing the difference in the surface state and light-emitting state of the light-emitting layer when the output of the laser is changed.

[0017] Figure 6 It is showing Figure 5 a table of processing conditions for the test shown, etc.

[0018] Figure 7 It is showing Figure 5 a table of observation conditions for the sample image described.

[0019] Figure 8 It is a table of measurement conditions for measuring the depth of the irradiation range and the non-irradiation range.

[0020] Figure 9 It is a table of measurement conditions for color intensity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Figure 1An information code according to an embodiment of the present disclosure shown is a concealment code CdS for recording concealed information. Together with a public code CdP for recording public information, the concealment code CdS is formed on a forming object such as a resin member and a metal member (hereinafter referred to as a marking member BM). By laser marking, the public code CdP and the concealment code CdS are marked at intervals on the flat surface portion FA of the marking member BM. The flat surface portion FA may be a portion where the base material of the marking member BM is exposed, or a coated surface of the marking member BM. The public code CdP and the concealment code CdS are, for example, two-dimensional codes such as QR Code (registered trademark). The public code CdP and the concealment code CdS record information respectively through a two-dimensional arrangement of a plurality of units Ce including bright color units Cew and dark color units Ceb.

[0022] The public code CdP is a two-dimensional code (visible code) that can be visually confirmed by normal visual observation. The bright color units Cew of the public code CdP are portions that remain in a textured state without being irradiated with laser. On the other hand, the dark color units Ceb of the public code CdP are portions where the surface texture deteriorates by laser irradiation. The public code CdP enables the reading of public information by utilizing the brightness difference (difference in visible light reflectance) generated between the non-deteriorated bright color units Cew and the deteriorated dark color units Ceb.

[0023] Different from the public code CdP, the concealment code CdS is a two-dimensional code (invisible code) that cannot be visually confirmed by normal visual observation. The concealment code CdS can be read by irradiating invisible light in a specific wavelength range. In the case where invisible light is not irradiated, the concealment code CdS is actually invisible. For example, if ultraviolet light is irradiated using an ultraviolet light source 24 such as black light (refer to Figure 2 ), the concealment code CdS can be read by emitting visible light.

[0024] Specifically, the concealment code CdS includes a light-emitting layer 50, a strong light-emitting portion 61, and a weak light-emitting portion 62. The light-emitting layer 50 contains an ultraviolet-responsive coating material (described in detail later) that emits light in response to ultraviolet light. The light-emitting layer 50 is formed in a thin film shape so as to cover the area of the flat surface portion FA that includes the formation range CA of the concealment code CdS. The strong light-emitting portion 61 is located at a position corresponding to the bright color unit Cew in the light-emitting layer 50. The strong light-emitting portion 61 is a portion not irradiated with laser. On the other hand, the weak light-emitting portion 62 is located at a position corresponding to the dark color unit Ceb in the light-emitting layer 50. The weak light-emitting portion 62 is a portion where the light-emitting function of the ultraviolet-responsive coating material is weakened compared to the strong light-emitting portion 61 by laser irradiation. The concealment code CdS enables the reading of concealed information by utilizing the brightness difference (luminance difference) generated between the bright color unit Cew based on the strong light-emitting portion 61 that can emit light strongly and the dark color unit Ceb based on the weak light-emitting portion 62 with a reduced light-emitting function.

[0025] The public code CdP is a two-dimensional code used in the Figure 2 circulation management system 110 shown in the figure. On the other hand, the concealment code CdS is a two-dimensional code used in the traceability system 120. In addition, the public code CdP can also be used in both the circulation management system 110 and the traceability system 120.

[0026] <Supply Chain Management System>

[0027] The circulation management system 110 and the traceability system 120 are management systems that manage the supply chain SC constructed by many traders TR. The supply chain SC is a chain of traders used to deliver industrial products, agricultural products, aquatic products, etc. to end-users. As an example, in the supply chain SC for delivering industrial products to consumers, material suppliers, component suppliers TR1, assembly suppliers TR2, and finished product manufacturers TR3, etc. are included in the traders TR.

[0028] The circulation management system 110 uses the public code CdP to collect transaction records of transaction items between traders TR. The circulation management system 110 is composed of an input terminal 11, a laser processing machine 12, a code reader 13, and a system server 10, etc. The input terminal 11, the laser processing machine 12, and the code reader 13 are appropriately set in the facilities of each trader TR. The input terminal 11, the laser processing machine 12, and the code reader 13 are connected to the system server 10 set in a data center, etc. through a network.

[0029] The input terminal 11 is, for example, a personal computer, a tablet terminal, etc. The basic information (hereinafter referred to as item information) of the transaction items supplied to the supply chain SC is input into the input terminal 11 in a prescribed format. For example, the item name, production place, production equipment, producer, etc. are item information. The input terminal 11 sends the item information of the transaction items shipped from the trader TR to the system server 10.

[0030] The laser processing machine 12 is a laser marking device that imprints the public code CdP on the transaction items shipped from the trader TR. A fiber laser marking machine, a UV laser marking machine, a CO 2 laser marking machine, etc. can be used as the laser processing machine 12. Through the imprinting of the laser processing machine 12, the public code CdP circulates together with the transaction items. The laser processing machine 12 can imprint the public code CdP on the imprinting member BM (refer to Figure 1 ) formed of various materials such as resin, metal, ceramic, paper, wood, glass, and rubber through laser marking.

[0031] In addition, among traders TR to which the public code CdP for printing at the time of shipment is attached, instead of the laser processing machine 12, a label printer is used. The label printer is an output device for printing the public code CdP on a paper medium. The label printer is configured to be able to perform printing in color or grayscale. The paper medium on which the public code CdP is printed is pasted onto the packaging or outer box of the traded item at the time of shipment, and is circulated in a state of being attached to the traded item.

[0032] The code reader 13 is a reading device that obtains the public information recorded in the public code CdP by reading the public code CdP. The code reader 13 obtains the public information recorded in the public code CdP and sends the obtained public information to the system server 10.

[0033] The system server 10 is a host node capable of communicating with the input terminal 11, the laser processing machine 12, and the code reader 13. The system server 10 registers the item information obtained from the input terminal 11 in the database. The system server 10 prepares public information associated with the item information and generates a public code CdP recording the public information. The system server 10 sends image data of the generated public code CdP, etc., to the laser processing machine 12 located at the source of the item information as a process of issuing the public code CdP. The issued public code CdP is circulated together with the traded item, and if it is read by the code reader 13 of another trader TR, the system server 10 accumulates the transaction record of the traded item of that trader TR.

[0034] The traceability system 120 is used in combination with the circulation management system 110 and accumulates transaction records in the same way as the circulation management system 110. That is, the circulation management system 110 corresponds to the old management system, and the traceability system 120 corresponds to the new management system. The traceability system 120 does not actually make changes to the existing circulation management system 110, but operates together with the circulation management system 110. In addition to the record generation function of accumulating transaction records using the concealment code CdS, the traceability system 120 also has a record reference function of providing the accumulated transaction records in a referable manner. In the traceability system 120, for the purpose of preventing tampering of transaction records, blockchain technology is used in the management of transaction records.

[0035] The traceability system 120 is composed of a code reader 23, an ultraviolet light source 24, a history management server 20, etc. And in the traceability system 120, the input terminal 11 and the laser processing machine 12, etc., of the circulation management system 110 are used. The code reader 23 and the input terminal 11 are connected to the history management server 20 provided in a data center, etc., via a network.

[0036] The code reader 23 and the ultraviolet light source 24 are provided in the facilities of the trader TR (such as the assembly supplier TR2) who incorporates the transaction item engraved with the hidden code CdS. The code reader 23 is a reading device that reads the hidden information recorded in the hidden code CdS. The code reader 23 is configured to scan the same object (the engraving component BM, refer to Figure 1 ), so it can also be physically integrated with the code reader 13. In other words, the code reader 13 of the circulation management system 110 can also be utilized in the traceability system 120.

[0037] The code reader 23 is composed of an imaging sensor formed by two-dimensionally arranging CCD elements, a signal processing unit 41, etc. The imaging sensor outputs a captured image (hereinafter referred to as a code captured image) of the hidden code CdS to the signal processing unit 41. The signal processing unit 41 has a storage unit that stores a code reading program, etc., a processor that executes code reading processing based on the code reading program, and a RAM. Through the code reading processing, the signal processing unit 41 decodes the reading signal (code captured image) of the imaging sensor according to a specified rule, and obtains the hidden information recorded in the hidden code CdS. Based on the obtained hidden information, the signal processing unit 41 communicates with the resume management server 20 for leaving a transaction record.

[0038] In addition, a smartphone, a tablet terminal, etc. with a camera function can be used as the code reader 23. In such a manner, a dedicated application program (hereinafter referred to as a code reading application) equivalent to the code reading program is provided and installed on the smartphone, etc. The code reading application can also perform the reading of the public code CdP in addition to the reading of the hidden code CdS.

[0039] When the code reader 23 reads the hidden code CdS, the ultraviolet light source 24 irradiates the engraving component BM (refer to Figure 1 ) with ultraviolet light as invisible light. The ultraviolet light source 24 has a plurality of ultraviolet LEDs and emits ultraviolet light in the wavelength band of 300 - 380 nm (as an example, the wavelength is 375 nm). Through the irradiation of ultraviolet light by the ultraviolet light source 24, the shooting of the hidden code CdS by the code reader 23 can be performed.

[0040] The resume management server 20 is a host node that can communicate with the input terminal 11 and the laser processing machine 12 in addition to the code reader 23. The resume management server 20 is mainly composed of a computer having a processing unit 31, a RAM 32, a storage unit 33, an input / output interface, and a bus connecting them. The processing unit 31 is a hardware for arithmetic processing combined with the RAM 32. The processing unit 31 performs various processes related to data management by accessing the RAM 32. Management programs related to data management are stored in the storage unit 33.

[0041] The resume management server 20 acquires the item information sent from the input terminal 11 to the system server 10. Based on the acquisition of the item information, the resume management server 20 generates a blockchain associated with the transaction item, and it is a blockchain for storing the item information and transaction records. When the resume management server 20 acquires a notice from the code reader 23 of each trader TR indicating that the concealment code CdS has been read, it accumulates the transaction records of the trader TR that is the source of the notice in association with the transaction item in the blockchain.

[0042] When the resume management server 20 acquires a notice from the code scanner 23, it generates a new block for storing the transaction records and the like of the trader TR that is the source of the notice. In the new block, in addition to the current transaction record, it also includes a hash value calculated based on the previous block. The generation of the hash value uses a hash function such as SHA-256, for example. The resume management server 20 generates a hash value with a number of bits less than the data volume that can be recorded in the concealment code CdS. The hash value is data that maintains a specified number of bits (for example, 256 bits), and it is data that reflects the item information and transaction records.

[0043] The resume management server 20 generates a concealment code CdS that records at least the above-mentioned hash value as concealment information. The resume management server 20 issues the generated concealment code CdS to the laser processing machine 12. The laser processing machine 12 engraves the concealment code CdS at a position adjacent to the public code CdP, for example. As a result, the hash value reflecting the item information and transaction records is recorded in the concealment code CdS and can circulate together with the transaction item.

[0044] In addition, in the traceability system 120, one concealment code CdS can be continuously used by multiple traders TR, or a new concealment code CdS can be issued to each trader TR. In the method of issuing a new concealment code CdS to each trader TR, based on the generation of the transaction records of each trader TR, the latest hash value reflecting the transaction records is generated. The resume management server 20 newly generates a concealment code CdS that records the latest hash value as concealment information and provides the data of the new concealment code CdS to the laser processing machine 12 of the facility of the trader TR that has conducted the transaction. As a result, as the project transaction progresses, the content (hash value) of the concealment code CdS is continuously updated to reflect the content of the transaction records up to that point. In addition, since the concealment information is mainly composed of the hash value, even if the project transaction develops in the supply chain SC, the data volume of the concealment information can be maintained stably.

[0045] The resume management server 20 can further issue a traceability code QRt. The traceability code QRt is a two-dimensional code such as a QR code attached to the final product FP supplied through the supply chain SC. The traceability code QRt enables the consumer who has obtained the final product FP to confirm the transaction record. As an example, the hash value calculated from the last block of the blockchain and the IP address or URL indicating the consultation destination of the transaction record are recorded in the traceability code QRt.

[0046] For example, the consumer of the final product FP can use a user terminal UT such as a smartphone and a tablet terminal to view the transaction record of the final product FP by using a traceability confirmation application. Specifically, when the user terminal UT reads the traceability code QRt attached to the final product FP, it sends a reference request for the transaction record together with the hash value to the resume management server 20 that is the consultation destination. When the resume management server 20 receives the reference request, it extracts the item information and transaction record associated with the hash value and generates the data for provision. The resume management server 20 sends the generated data for provision to the user terminal UT that is the request source of the reference request. The consumer of the final product FP can confirm the transaction record resume by expanding the data for provision received from the resume management server 20 by using the traceability confirmation application.

[0047] <Concealment code formation process>

[0048] Next, based on Figure 3 the code formation process shown, and referring to Figure 1 and Figure 2 the details of the code formation method of the present disclosure for forming the concealment code CdS on the engraving part BM will be further described. In the code formation process, a part preparation process S10, a cleaning process S20, a coating agent preparation process S30, a masking process S40, a light emitting layer formation process S50, and a laser engraving process S60 are sequentially implemented.

[0049] In the part preparation process S10, the engraving part BM that is the object for engraving the concealment code CdS is prepared. In the cleaning process S20, at least the flat part FA including the formation range CA of the concealment code CdS is cleaned on the outer surface of the engraving part BM prepared in the part preparation process S10. In the cleaning process S20, for example, a non-water-soluble solvent or the like is used to remove stains such as grease and dust attached to the flat part FA.

[0050] In the coating agent preparation step S30, a coating agent to be applied to the flat portion FA of the engraving member BM is prepared. The coating agent is a reaction coating that emits light upon reaction with invisible light, and contains an ultraviolet reaction coating that emits light upon reaction with ultraviolet light. As an example, the coating agent is a colorless and transparent liquid product generated by mixing an ultraviolet reaction coating, an acrylic-based transparent coating, and a diluent serving as a solvent at a prescribed mixing ratio (e.g., 1:60:60, etc.). As an example of the ultraviolet reaction coating used in the present embodiment, a super bright fluorescent leak detector (DF-300 Liquid) manufactured by MARKTEC Co., Ltd. can be cited. The composition of the ultraviolet reaction coating contains 45 to 55 wt% of a water-soluble fluorescent coating and 45 to 55 wt% of water.

[0051] In the masking step S40, the periphery of the formation range CA of the concealment code CdS is masked. The outer edge of the formation range CA corresponds to the outer edge of the quiet zone of the concealment code CdS. As an example, for the formation range CA, a range enclosed by a mask is set so as to ensure a blank area of at least several millimeters on all four sides.

[0052] In the light-emitting layer formation step S50, the coating agent is applied to the flat portion FA after the masking step S40. Thereby, a colorless and transparent light-emitting layer 50 (refer to Figure 1 ) is formed in the range including the formation range CA. The application of the coating agent is performed using a coating device 25 such as a spray gun, for example. The coating device 25 sprays the liquid coating agent prepared in the coating agent preparation step S30 onto the flat portion FA by jetting high-pressure air or gas. After spraying, a prescribed drying time (e.g., about ten minutes) for drying the coating agent is ensured. In the light-emitting layer formation step S50, the process of applying the coating agent using the coating device 25 and the process of drying the applied coating agent are repeated multiple times (e.g., about three times). Through the above, the light-emitting layer 50 is formed as a coating film containing an ultraviolet reaction coating.

[0053] In addition, in the light-emitting layer formation step S50, the process of applying a coating agent containing an ultraviolet reaction coating can also be performed by a printing method, or can also be performed by a stamping method or the like. In addition, the mask around the light-emitting layer 50 can be removed either after the drying of the coating agent in the light-emitting layer formation step S50 or after the laser engraving step S60. And, in the case where the coating process and the drying process are repeatedly performed, the light-emitting layer 50 is formed as a layered structure in which extremely thin coating films are overlapped. Therefore, if multiple coating films are formed in layers, it can be regarded as repeatedly performing the coating process and the drying process.

[0054] In the laser marking step S60, the data of the confidentiality code CdS provided from the history management server 20 is prepared by the laser processing machine 12. In the laser marking step S60, the confidentiality code CdS is marked on the light emitting layer 50 by irradiating the laser by the laser processing machine 12. The laser processing machine 12 irradiates the light emitting layer 50 with a laser in the wavelength band of ultraviolet light (for example, a wavelength of 343 nm).

[0055] In the laser engraving process S60, in the light-emitting layer 50, the position corresponding to the dark cell Ceb of the hidden code CdS is irradiated with laser. On the other hand, in the light-emitting layer 50, the position corresponding to the bright cell Cew is not irradiated with laser. As a result, the luminous function of the position that becomes the dark cell Ceb is weakened relative to the luminous function of the position that becomes the bright cell Cew. As a result, the position corresponding to the bright cell Cew in the light-emitting layer 50 becomes a strong luminous portion 61, which reacts with ultraviolet light and emits light more strongly. In contrast, the position corresponding to the dark cell Ceb in the light-emitting layer 50 becomes a weak luminous portion 62, which becomes a luminous state darker than the strong luminous portion 61.

[0056] <Description of the structure that reduces the light-emitting function>

[0057] Next, based on Figure 4 The principle of light emission of ultraviolet reactive paint and the structure for reducing such light emission function are explained.

[0058] The ultraviolet reactive paint contains a water-soluble fluorescent dye. The fluorescent paint emits a blue-white fluorescent color when irradiated with ultraviolet light. The fluorescent dye excites electrons by absorbing the energy of ultraviolet light. The excited electrons become unstable and try to return to the stable ground state. When the electrons return to the ground state, they radiate excess energy as electromagnetic waves. The wavelength of the radiated electromagnetic waves is longer than the wavelength of the irradiated ultraviolet light. Based on the above, the fluorescent dye becomes a luminescent state of radiating visible light with a longer wavelength than the ultraviolet light by irradiation with ultraviolet light.

[0059] The light-emitting function of such fluorescent paint is weakened by laser irradiation. Figure 4 The results of the transmittance test shown in the figure will be described in detail. Figure 4In the transmittance test shown, three measurement pieces are prepared. The first measurement piece is a measurement piece of only the colorless and transparent plate-shaped quartz plate 140 (hereinafter referred to as the reference measurement piece MSR). The second measurement piece is a measurement piece formed by coating an acrylic-based transparent coating on one side of the quartz plate 140 to form a transparent coating film 141 that does not contain an ultraviolet-reactive coating (hereinafter referred to as the first measurement piece MS1). The third measurement piece is a measurement piece formed by coating a coating agent on one side of the quartz plate 140 to form a fluorescent coating film 142 containing an ultraviolet-reactive coating (hereinafter referred to as the second measurement piece MS2). The coating agent coated on the second measurement piece MS2 has the same composition as the coating agent prepared in the coating agent preparation step S30 (refer to Figure 3 ).

[0060] Similar to the laser engraving step S60 (refer to Figure 3 ), the reference measurement piece MSR, the first measurement piece MS1, and the second measurement piece MS2 are processed with a laser in the ultraviolet light band (for example, a wavelength of 343 nm). In the reference measurement piece MSR, the transmittance before laser irradiation (pre-processing transmittance) is the same as the transmittance after laser irradiation (post-processing transmittance). Similarly, in the first measurement piece MS1, the pre-processing transmittance is the same as the post-processing transmittance.

[0061] On the other hand, in the second measurement piece MS2, although the post-processing transmittance (55%) is lower than the transmittance of the first measurement piece MS1 (92%), it increases significantly relative to the pre-processing transmittance (38%). Due to such an increase in transmittance, in the processed fluorescent coating film 142, the absorption amount of the energy of the ultraviolet light absorbed by the fluorescent coating decreases. As a result, the amount of excited electrons decreases, and further, the amount of energy released as electromagnetic waves also decreases. Therefore, it can be speculated that the light-emitting function of emitting visible light deteriorates.

[0062] Due to the above, in the laser engraving step S60 of the code formation process (refer to Figure 3 ), the transmittance of the ultraviolet light at the position corresponding to the dark unit Ceb is higher than the transmittance at the position corresponding to the bright unit Cew. As a result, a weak light-emitting portion 62 with a weaker light-emitting function than the position corresponding to the bright unit Cew can be formed at the position corresponding to the dark unit Ceb.

[0063] <Laser Output Setting>

[0064] In the above-mentioned laser engraving step S60 (refer to Figure 3) The output of the laser irradiated therein is set to a value that does not discolor the surface of the light-emitting layer 50 and can reduce the light-emitting function of the ultraviolet-responsive coating. In the code formation method of the present disclosure, it is possible to quantitatively determine whether the output of the laser is appropriately set based on the surface state and the light-emitting state of the light-emitting layer 50 after the laser engraving step S60. Hereinafter, based on Figures 5 to 9 , and with reference to Figure 1 and Figure 2 , the details of the indices for determining the quality of the surface state and the light-emitting state of the light-emitting layer 50 will be described.

[0065] Here, in Figure 5 , the differences in the surface state and the light-emitting state of the light-emitting layer 50 in an experiment in which the laser output is changed in eight stages in the range of 0.08 W to 0.0033 W are shown. In the experiment shown in Figure 5 , as shown in Figure 6 , a measurement sample MS3 in which the light-emitting layer 50 is formed using a steel plate material 240 (for example, SPCC, etc.) on which black matte finish has been applied is used. Lasers under the conditions shown in Figure 6 with the above-mentioned respective outputs switched are irradiated to a plurality of test irradiation regions (for example, 1 mm × 1 mm) provided on the measurement sample MS3. In Figure 5 , it is described that the appearance of each test irradiation region observed under the conditions shown in Figure 7 using a microscope (VH-X7100) manufactured by KEYENCE Corporation is shown.

[0066] [1. Judgment Index for Surface State of Light-Emitting Layer]

[0067] As shown in Figure 5 , when the output of the laser irradiated in the laser engraving step S60 is excessively increased, the light-emitting layer 50 discolors (refer to laser outputs 0.08 W and 0.04 W). In this case, it is easy to visually confirm the hidden code CdS in a state where ultraviolet light is not irradiated. Such discoloration of the light-emitting layer 50 is caused by laser ablation of the outer surface of the light-emitting layer 50. Therefore, in the laser engraving step S60, the output of the laser is set so that the difference in depth between the non-irradiation range 161 where no laser is irradiated and the irradiation range 162 where the laser is irradiated (hereinafter, referred to as the depth difference) is within a specified range. Specifically, it is preferable to set the output of the laser so that the depth difference is in the range of 0 to 1.0 μm, and more preferably in the range of 0 to 0.2 μm. For example, in the sample group shown in Figure 5 , the range of laser output of 0.0133 W or less is a preferable setting range.

[0068] Here, the non-irradiation range 161 is the range corresponding to the strong light-emitting part 61 and the bright color unit Cew. On the other hand, the irradiation range 162 is the range corresponding to the weak light-emitting part 62 and the dark color unit Ceb. Therefore, in the concealing code CdS (refer to Figure 1 ), taking the outer surface of the light-emitting layer 50 as the reference plane, the difference in depth between the strong light-emitting part 61 and the weak light-emitting part 62 from the reference plane is the depth difference. Moreover, as described above, the depth difference is preferably in the range of 0 to 1.0 μm, more preferably in the range of 0 to 0.2 μm.

[0069] For example, using a white light interferometer (nexview) from ZYGO, measure the depths of the above non-irradiation range 161 (strong light-emitting part 61) and irradiation range 162 (weak light-emitting part 62) under the conditions shown in Figure 8 . For example, perform depth measurement with the vicinity of the center of one unit Ce (refer to Figure 1 ) as the object. As an example, take the average value of the depth values measured in multiple bright color units Cew as the depth value of the non-irradiation range 161 (strong light-emitting part 61), and take the average value of the depth values measured in multiple dark color units Ceb as the depth value of the irradiation range 162 (weak light-emitting part 62).

[0070] In addition, the maximum value, minimum value, or median value of the depth values measured in multiple bright color units Cew can also be used as the depth value of the non-irradiation range 161, and the maximum value, minimum value, or median value of the depth values measured in multiple dark color units Ceb can be used as the depth value of the irradiation range 162. Also, the depth values measured in a specific bright color unit Cew and a specific dark color unit Ceb can be used as the depth values representing the non-irradiation range 161 and the irradiation range 162, respectively.

[0071] In the experiment shown in Figure 5 , when the laser output is 0.02 W or 0.0167 W, the depth of the irradiation range 162 changes significantly in part. This is a phenomenon caused by the processing threshold of the black painted part of the steel plate material 240 being lower than the processing threshold of the ultraviolet-responsive coating.

[0072] Specifically, the output of a laser above 0.04W exceeds the processing threshold of the ultraviolet-responsive coating. Therefore, when the laser output is 0.08W or 0.04W, the output of the laser decreases due to the processing of the ultraviolet-responsive coating, so no processing occurs in the black-coated portion of the steel plate material 240. On the other hand, the output of a laser below 0.0133 is lower than the processing thresholds of both the ultraviolet-responsive coating and the black-coated portion. Therefore, when the laser output is 0.0133, 0.01, 0.0067, or 0.0033W, although the laser passes through the light-emitting layer 50 and reaches the black-coated portion, it does not cause processing of the black-coated portion.

[0073] In contrast, the output of a laser of 0.02W or 0.0167W does not exceed the processing threshold of the ultraviolet-responsive coating but exceeds the processing threshold of the black-coated portion. Therefore, when the laser output is 0.02W or 0.0167W, the laser passes through the light-emitting layer 50 and reaches the black-coated portion, causing processing of a part of the black-coated portion, such as evaporation or impact in the black-coated portion where the laser arrives. As a result, the light-emitting layer 50 covering the upper part of the black-coated portion is pressed, causing local protrusions in the light-emitting layer 50. Based on the above, it is more preferable to appropriately adjust the output of the laser according to the physical properties of the flat portion FA (refer to Figure 1 ), and in addition to satisfying the above conditions for the processing depth, it is also set to a value that does not exceed the processing threshold of the flat portion FA.

[0074] [2. Judgment Index for Luminescence State during Ultraviolet Light Irradiation]

[0075] As Figure 5 shown, when the output of the laser irradiated in the laser engraving process S60 is insufficient, the reduction in the luminescence function is insufficient (refer to laser outputs of 0.0067W and 0.0033W). In this case, even when ultraviolet light is irradiated, it is difficult to read the hidden code CdS. To avoid such a situation, in the laser engraving process S60, the output of the laser is set so that the value obtained by subtracting the color intensity of the irradiation range 162 from the color intensity of the non-irradiation range 161 (hereinafter referred to as the color intensity difference) is within a specified range.

[0076] Here, the definition of the above color intensity will be explained. The color intensity is a value representing the color in the converted image obtained by converting the captured image of the light-emitting layer 50 (hereinafter referred to as the intensity measurement image) into grayscale, with the value corresponding to black set to 1 and the value corresponding to white set to 100. The color intensity corresponds to the value representing the luminescence brightness during ultraviolet light irradiation. The higher the position that emits light with high brightness, the larger the value, and the lower the position that emits light with low brightness, the smaller the value. Using a black light manufactured by Ohm Electric Co., a camera manufactured by Panasonic Corporation, and image processing software manufactured by Adobe Inc., etc.,Figure 9 Measure the color intensity under the conditions shown.

[0077] In the measurement of color intensity, first, while irradiating ultraviolet light with black light, use a camera to photograph the light-emitting layer 50 (the hidden code CdS) to generate a full-color intensity measurement image. Use image processing software to grayscale the intensity measurement image. In the converted image converted to grayscale, each pixel only retains the luminance information. The value representing the luminance of each pixel (gray value) and shown as a percentage is the color intensity.

[0078] In the laser engraving process S60, it is preferable to set the output of the laser so that the color intensity difference is 30 or more, and more preferably 35 or more. For example, in Figure 5 the sample group shown, the range of laser output of 0.0133 W or more becomes the preferable setting range. Also in the case of the hidden code CdS (refer to Figure 1 ), the value obtained by subtracting the color intensity of the weak light-emitting part 62 from the color intensity of the strong light-emitting part 61 becomes the color intensity difference. And, as described above, it is preferable that the color intensity difference is 30 or more, and more preferably 35 or more.

[0079] In the above measurement of color intensity, the average gray value of the pixel group in the vicinity of the center where one unit Ce (refer to Figure 1 ) is reflected, specifically, in the range of 0.8 mm square in the center of the 1 mm square unit Ce is used as the color intensity of the unit Ce. And, the value obtained by further averaging the color intensities of a plurality of bright units Cew is used as the color intensity value of the non-irradiated range 161 (strong light-emitting part 61), and the value obtained by averaging the color intensities of a plurality of dark units Ceb is used as the color intensity value of the irradiated range 162 (weak light-emitting part 62).

[0080] Alternatively, the maximum value, minimum value, or median value of the color intensities of a plurality of bright units Cew can be used as the value representing the color intensity of the non-irradiated range 161, and the maximum value, minimum value, or median value of the color intensities of a plurality of dark units Ceb can be used as the value representing the color intensity of the irradiated range 162. Also, the color intensity values of a specific bright unit Cew and a specific dark unit Ceb can be used as the values representing the color intensities of the non-irradiated range 161 and the irradiated range 162, respectively.

[0081] <Summary of the Embodiment>

[0082] In the embodiment described so far, the light-emitting function at the position corresponding to the dark unit Ceb in the light-emitting layer 50 containing the ultraviolet-responsive coating is weaker than that at the position corresponding to the bright unit Cew. Therefore, by irradiating ultraviolet light, which is invisible light, the arrangement of the dark unit Ceb and the bright unit Cew with different light-emitting intensities is revealed. Based on the above, since the reading of the hiding code CdS does not require a special reading device (code reader 23), the convenience of the hiding code CdS can be ensured.

[0083] In addition, in this embodiment, the light-emitting layer 50 is formed over the entire range including the formation range CA, and each dark unit Ceb is formed in such an integrated light-emitting layer 50. Therefore, compared with the method of separately forming minute coatings at the positions corresponding to the dark units Ceb, it is easier to ensure the durability of the coatings. Based on the above, for the engraving member BM used in various environments, the hiding code CdS that is not easily erased can be engraved. As a result, the convenience of the hiding code CdS can be further improved.

[0084] In addition, in this embodiment where the dark units Ceb are laser-engraved, compared with the method of printing the dark units Ceb, high resolution of the hiding code CdS can be achieved while ensuring durability. Therefore, miniaturization of the formation range CA of the hiding code CdS can be achieved while ensuring the recordable information amount. As a result, the hiding code CdS can be engraved on a narrow planar portion FA, so the convenience of the hiding code CdS can be further improved.

[0085] In this embodiment, in the laser engraving step S60 of irradiating the laser, the transmittance of the invisible light at the position corresponding to the dark unit Ceb is higher than that at the position corresponding to the bright unit Cew. Based on the above, less energy is absorbed by the fluorescent coating, so the light-emitting function at the position corresponding to the dark unit Ceb can be reliably reduced. As a result, the brightness difference between the bright unit Cew and the dark unit Ceb when ultraviolet light is irradiated increases, so the reading of the hiding code CdS becomes easier.

[0086] In addition, in the laser engraving step S60 of this embodiment, the output of the laser is set so as not to discolor the light-emitting layer 50. Based on the above, it is possible to avoid the situation where the hiding code CdS is recognized in a state where ultraviolet light is not irradiated. As a result, a hiding code CdS with higher concealability can be provided.

[0087] Specifically, in the present embodiment, the output of the laser is set such that the difference in depth between the non-irradiation range 161 where the laser is not irradiated and the irradiation range 162 where the laser is irradiated is in the range of 0 to 1.0 μm, more preferably in the range of 0 to 0.2 μm. In other words, in the hiding code CdS, it is preferable that the difference in depth between the strong light-emitting portion 61 and the weak light-emitting portion 62 from the reference plane is in the range of 0 to 1.0 μm, more preferably in the range of 0 to 0.2 μm. By setting the range of such a depth difference, the hiding property of the hiding code CdS can be more reliably ensured.

[0088] In addition, in the laser engraving step S60 of the present embodiment, the output of the laser is set to reduce the light-emitting function of the ultraviolet-responsive coating material. Based on the above, the light-emitting function corresponding to the position of the dark unit Ceb is reliably weakened, so the brightness difference between the bright unit Cew and the dark unit Ceb when irradiated with ultraviolet light can be ensured. Therefore, the reading of the hiding code CdS in the state irradiated with ultraviolet light becomes easier.

[0089] Specifically, in the present embodiment, the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the captured image of the light-emitting layer 50 is converted to grayscale. Moreover, the color value in the converted image that has been grayscaled is defined as the color intensity. And in the laser engraving step S60, the output of the laser is set such that the value obtained by subtracting the color intensity of the irradiation range 162 irradiated with the laser from the color intensity of the non-irradiation range 161 where the laser is not irradiated is 30 or more, more preferably 35 or more. In other words, in the hiding code CdS, it is preferable that the value obtained by subtracting the color intensity of the weak light-emitting portion 62 from the color intensity of the strong light-emitting portion 61 is 30 or more, more preferably 35 or more. By setting the range of such a color intensity difference, the readability of the hiding code CdS in the state irradiated with ultraviolet light can be further ensured.

[0090] And in the light-emitting layer forming step S50 of the present embodiment, the processes of coating the coating agent and drying the coated coating agent are repeated multiple times. Therefore, the thickness of the coating film formed as the light-emitting layer 50 can be sufficiently ensured. As a result, by irradiating with ultraviolet light, the bright unit Cew can emit light with a higher brightness. Thus, the brightness difference between the bright unit Cew and the dark unit Ceb when irradiated with ultraviolet light increases, so the reading of the hiding code CdS becomes easy.

[0091] In addition, in the above embodiment, the hiding code CdS corresponds to the "information code", the bright unit Cew corresponds to the "bright area", the dark unit Ceb corresponds to the "dark area", and the engraving member BM corresponds to the "formation object".

[0092] (Other embodiments)

[0093] As described above, an embodiment of the present disclosure has been described. However, the present disclosure is not limited to the above-described embodiment and can be applied to various embodiments and combinations without departing from the gist of the present disclosure.

[0094] In Modification 1 of the above-described embodiment, instead of the public code CdP, the concealment code CdS is engraved on the engraving member BM. That is, two concealment codes CdS are formed side by side on one engraving member BM. One of the public codes CdP is an information code used in the circulation management system 110. According to the above Modification 1, public information can be recorded without impairing the designability of the engraving member BM.

[0095] In Modification 2 of the above-described embodiment, the concealment code CdS is formed so as to overlap with the public code CdP. That is, after the public code CdP is laser-engraved on the engraving member BM, a transparent light-emitting layer 50 is formed so as to cover the public code CdP. Then, the public code CdP is laser-engraved on the light-emitting layer 50 covering the public code CdP. In the above Modification 2, the formation position of the invisible concealment code CdS can be grasped based on the position of the visible public code CdP.

[0096] In Modification 3 of the above-described embodiment, instead of the above-described hash value, the unique identification information (UID) for identifying the item manufactured by the trader TR is recorded as the concealment information in the concealment code CdS. As in such Modification 3, the concealment information recorded in the concealment code CdS can also be appropriately changed.

[0097] Moreover, the use of the concealment code CdS is not limited to the management of the supply chain SC in the traceability system 120 and can also be used by a system different from the traceability system 120. In this case, the concealment code CdS can be used alone without being combined with the public code CdP. As described above, the concealment code CdS of the present disclosure is an information code particularly suitable for various uses that require recording information without making the engraving conspicuous.

[0098] In the concealment code CdS of Modification 4 of the above-described embodiment, instead of ultraviolet light, infrared light is used as the invisible light. That is, the coating agent for the light-emitting layer contains a fluorescent coating that emits visible light by irradiation with infrared light. Moreover, in the laser engraving process S60 (refer to Figure 3 ), the light-emitting function of such a light-emitting layer is weakened by laser engraving. Also, for reading the concealment code CdS, instead of the ultraviolet light source 24 (refer to Figure 2 ), an infrared light source is used.

[0099] In Modification 5 of the above-described embodiment, the repetition of the process of applying the coating agent and the process of drying the applied coating agent is omitted. As in such Modification 5, as long as the emission luminance of the light-emitting layer 50 at the time of invisible light irradiation can be sufficiently ensured, the details of the light-emitting layer forming step S50 can be appropriately changed. Further, the blending ratio of the coating agent can also be appropriately changed.

[0100] In Modification 6 of the above-described embodiment, the public code CdP and the hidden code CdS are different versions from each other. Further, in Modification 7 of the above-described embodiment, the public code CdP and the hidden code CdS are different sizes from each other. That is, the hidden code CdS may be a QR code having a larger size than the public code CdP, or may be a QR code having a smaller size than the public code CdP. Further, in Modification 8 of the above-described embodiment, the public code CdP and the hidden code CdS are different versions (number of cells) from each other. That is, the version of the hidden code CdS may be larger than the public code CdP, or may be smaller than the public code CdP. As in these Modifications 6 to 8, the specifications of the public code CdP and the hidden code CdS can be appropriately changed.

[0101] Further, the two-dimensional codes used as the public code CdP and the hidden code CdS are not limited to QR codes. The public code CdP and the hidden code CdS may use two-dimensional codes different from QR codes. Further, the public code CdP and the hidden code CdS may be two-dimensional codes or one-dimensional codes based on different standards from each other.

[0102] In the above-described embodiment, the black cells of the original data of the two-dimensional code are associated with the dark cells Ceb of the laser-engraved hidden code CdS, and the white cells of the original data are associated with the bright cells Cew of the laser-engraved hidden code CdS. On the other hand, in Modification 9 of the above-described embodiment, the association between the black cells and the white cells of the original data and the engraved dark cells Ceb and bright cells Cew is swapped. That is, the black cells of the original data are engraved as the bright cells Cew, and the white cells of the original data are engraved as the dark cells Ceb.

[0103] In the above-described embodiment, different from the hidden code CdS used in the supply chain SC, a traceability code QRt is issued and attached to the final product FP. However, the public code CdP may also be registered in the history management server 20 and used as the traceability code QRt. Further, the final product FP supplied through the supply chain SC can be appropriately changed. For example, various items such as automobiles, batteries, semiconductors, fresh foods, aquatic products, foods, flowers, pharmaceuticals, and chemical products can be managed by the traceability system 120.

[0104] The hash function used in the resume management server 20 is a cryptographic hash function, which has the characteristics that it will not output the same hash value for different inputs and it is substantially impossible to infer the input from the output hash value. For example, instead of the above-mentioned SHA-256, encryption algorithms such as SHA-1, SHA-2, and SHA-3 can be appropriately used according to the output length (number of bits) of the concealment code CdS that can record the concealment information. In addition, the code generation process implemented by the resume management server 20 can also be implemented in the control circuit of the laser processing machine 12 on the edge side.

[0105] In the above embodiment, each function provided by the resume management server, the code reader, etc. can also be provided by software, the hardware that executes the software, only by software, only by hardware, or by a combined combination of them. When providing such a function by an electronic circuit as hardware, each function can also be provided by a digital circuit including many logic circuits or an analog circuit.

[0106] The processing unit (signal processing unit) of the above embodiment can be configured to include at least one arithmetic core such as a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). And the processing unit can be further configured to include an FPGA (Field-Programmable Gate Array), an NPU (Neural network Processing Unit), and other IP cores with dedicated functions.

[0107] Regarding the adoption of each storage unit in the above embodiment, the form of the storage medium (non-transitory tangible storage medium) storing each program can be appropriately changed. For example, the storage medium is not limited to the configuration set on the circuit board, and can be configured to be provided in the form of a memory card, etc., inserted into the socket part, and electrically connected to the bus of the computer. And the storage medium can also be an optical disc, a hard disk drive, a solid state drive, etc. that are used as the replication basis or distribution source of the program to the computer.

[0108] The control unit and method described in the present disclosure can also be implemented by a dedicated computer that constitutes a processor programmed to execute one or more functions embodied by a computer program. Alternatively, the device and method described in the present disclosure can be implemented by dedicated hardware logic circuits. Alternatively, the device and method described in the present disclosure can be implemented by one or more dedicated computers constituted by a combination of a processor that executes a computer program and one or more hardware logic circuits. Additionally, the computer program can also be stored, as instructions executable by a computer, in a non-transitory tangible recording medium readable by the computer.

[0109] (Disclosure of Technical Ideas)

[0110] This specification discloses multiple technical ideas described in the following items. Some items are described in a multiple dependent form that alternatively references preceding items in subsequent items. And some items are described in a multiple dependent form that references items in other multiple dependent forms. These items described in the multiple dependent form define multiple technical ideas.

[0111] (Technical Idea 1)

[0112] A code formation method is a code formation method for forming an information code (CdS) that records information through an arrangement of a bright color region (Cew) and a dark color region (Ceb) in a formation object (BM), and includes:

[0113] a step of forming a light-emitting layer (50) (S50) including a formation range (CA) of the information code by applying a coating agent containing a reaction coating material that reacts with invisible light to emit light to the above-mentioned formation object; and

[0114] a step of weakening the light-emitting function of the above-mentioned dark color region (S60) compared to the above-mentioned bright color region by irradiating a laser at a position corresponding to the above-mentioned dark color region in the above-mentioned light-emitting layer.

[0115] (Technical Idea 2)

[0116] According to the code formation method described in Technical Idea 1, in the step of irradiating the laser, the transmittance of the above-mentioned invisible light at a position corresponding to the above-mentioned dark color region is made higher than the transmittance at a position corresponding to the above-mentioned bright color region.

[0117] (Technical Idea 3)

[0118] According to the code formation method described in Technical Idea 1 or 2, in the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set so as not to discolor the above-mentioned light-emitting layer.

[0119] (Technical Idea 4)

[0120] According to the code formation method described in any one of Technical Ideas 1 to 3, in the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set so that the difference in depth between the non-irradiation range (161) where the above-mentioned laser is not irradiated and the irradiation range (162) where the above-mentioned laser is irradiated is in the range of 0 to 1.0 μm.

[0121] (Technical Idea 5)

[0122] According to the code formation method described in any one of Technical Ideas 1 to 3, in the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set so that the difference in depth between the non-irradiation range (161) where the above-mentioned laser is not irradiated and the irradiation range (162) where the above-mentioned laser is irradiated is in the range of 0 to 0.2 μm.

[0123] (Technical Idea 6)

[0124] According to the code formation method described in any one of Technical Ideas 1 to 5, in the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set so as to reduce the above-mentioned light-emitting function of the above-mentioned reaction coating.

[0125] (Technical Idea 7)

[0126] According to the code formation method described in any one of Technical Ideas 1 to 6, if the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the value of the color in the converted image obtained by converting the captured image of the above-mentioned light-emitting layer into grayscale is defined as the color intensity, then

[0127] In the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set so that the value obtained by subtracting the above-mentioned color intensity of the irradiation range (162) where the above-mentioned laser is irradiated from the above-mentioned color intensity of the non-irradiation range (161) where the above-mentioned laser is not irradiated is 30 or more.

[0128] (Technical Idea 8)

[0129] According to the code formation method described in any one of Technical Ideas 1 to 6, if the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the value of the color in the converted image obtained by converting the captured image of the above-mentioned light-emitting layer into grayscale is defined as the color intensity, then,

[0130] In the step of irradiating the above-mentioned laser, the output of the above-mentioned laser is set such that the value obtained by subtracting the color intensity of the irradiated range (162) where the above-mentioned laser is irradiated from the color intensity of the non-irradiated range (161) where the above-mentioned laser is not irradiated is 35 or more.

[0131] (Technical idea 9)

[0132] According to the code formation method described in any one of Technical ideas 1 to 8, in the step of forming the above-mentioned light-emitting layer, the process of coating the above-mentioned coating agent and the process of drying the coated above-mentioned coating agent are repeated multiple times.

[0133] (Technical idea 10)

[0134] It is an information code that records information through the arrangement of a bright color area (Cew) and a dark color area (Ceb), and includes:

[0135] A light-emitting layer (50) containing a reaction coating that reacts with invisible light to emit light;

[0136] A strong light-emitting part (61) located at a position in the above-mentioned light-emitting layer corresponding to the above-mentioned bright color area, which reacts with the above-mentioned invisible light to emit light; and

[0137] A weak light-emitting part (62) located at a position in the above-mentioned light-emitting layer corresponding to the above-mentioned dark color area, and the light-emitting function of the above-mentioned reaction coating is weaker than that of the above-mentioned strong light-emitting part.

[0138] (Technical idea 11)

[0139] According to the information code described in Technical idea 10, if the outer surface of the above-mentioned light-emitting layer is used as a reference plane, then

[0140] The difference in the depth from the reference plane of the above-mentioned strong light-emitting part and the depth from the reference plane of the above-mentioned weak light-emitting part is in the range of 0 to 1.0 μm.

[0141] (Technical idea 12)

[0142] According to the information code described in Technical idea 10, if the outer surface of the above-mentioned light-emitting layer is used as a reference plane, then,

[0143] The difference in the depth from the reference plane of the above-mentioned strong light-emitting part and the depth from the reference plane of the above-mentioned weak light-emitting part is in the range of 0 to 0.2 μm.

[0144] (Technical idea 13)

[0145] According to the information code described in any one of Technical ideas 10 to 12, if the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the color value in the converted image obtained by converting the captured image of the above-mentioned light-emitting layer into grayscale is defined as the color intensity, then,

[0146] The value obtained by subtracting the color intensity of the weak light-emitting part from the color intensity of the strong light-emitting part is 30 or more.

[0147] (Technical idea 14)

[0148] According to the information code described in any one of Technical ideas 10 to 12, if the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the value of the color in the converted image obtained by converting the captured image of the light-emitting layer into grayscale is defined as the color intensity, then

[0149] The value obtained by subtracting the color intensity of the weak light-emitting part from the color intensity of the strong light-emitting part is 35 or more.

Claims

1. A method for forming a code, which is a method for forming an information code (CdS) on a formation object (BM), and the information code is an information code that records information through the arrangement of bright regions and dark regions. The method for forming a code includes: A step (S50) of forming a light-emitting layer (50) including a formation range (CA) of the information code by applying a coating agent containing a reaction coating that reacts with invisible light to emit light to the formation object; and A step (S60) of weakening the light-emitting function of the dark region compared to the bright region by irradiating the position corresponding to the dark region in the light-emitting layer with a laser.

2. The method for forming a code according to claim 1, wherein, In the step of irradiating the laser, the transmittance of the invisible light at the position corresponding to the dark region is higher than the transmittance at the position corresponding to the bright region.

3. The method for forming a code according to claim 1, wherein, In the step of irradiating the laser, the output of the laser is set so as not to discolor the light-emitting layer.

4. The method for forming a code according to claim 1, wherein, In the step of irradiating the laser, the output of the laser is set such that the difference in depth between the non-irradiation range (161) where the laser is not irradiated and the irradiation range (162) where the laser is irradiated is in the range of 0 to 1.0 μm.

5. The method for forming a code according to claim 1, wherein, In the step of irradiating the laser, the output of the laser is set such that the difference in depth between the non-irradiation range (161) where the laser is not irradiated and the irradiation range (162) where the laser is irradiated is in the range of 0 to 0.2 μm.

6. The method for forming a code according to any one of claims 1 to 5, wherein, In the step of irradiating the laser, the output of the laser is set to reduce the light-emitting function of the reaction coating.

7. The method for forming a code according to any one of claims 1 to 5, wherein, If the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the value of the color in the converted image obtained by converting the captured image of the light-emitting layer into grayscale is defined as the color intensity, then In the step of irradiating the laser, the output of the laser is set such that the value obtained by subtracting the color intensity of the irradiation range (162) where the laser is irradiated from the color intensity of the non-irradiation range (161) where the laser is not irradiated is 30 or more.

8. The method for forming a code according to any one of claims 1 to 5, wherein, If the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the value of the color in the converted image obtained by converting the captured image of the light-emitting layer into grayscale is defined as the color intensity, then In the step of irradiating the laser, the output of the laser is set such that the value obtained by subtracting the color intensity of the irradiation range (162) where the laser is irradiated from the color intensity of the non-irradiation range (161) where the laser is not irradiated is 35 or more.

9. The method for forming a code according to claim 1, wherein, In the process of forming the above-mentioned light-emitting layer, the process of repeatedly coating the above-mentioned coating agent multiple times and the process of drying the coated above-mentioned coating agent are performed.

10. An information code that records information through the arrangement of bright color areas (Cew) and dark color areas (Ceb). Among them, It includes: A light-emitting layer (50) containing a reaction coating that reacts with invisible light to emit light; A strong light-emitting part (61) located at a position corresponding to the above-mentioned bright color area in the above-mentioned light-emitting layer, which reacts with the above-mentioned invisible light to emit light; And A weak light-emitting part (62) located at a position corresponding to the above-mentioned dark color area in the above-mentioned light-emitting layer, and the light-emitting function of the above-mentioned reaction coating is weaker than that of the above-mentioned strong light-emitting part.

11. The information code according to claim 10, Among them, If the outer surface of the above-mentioned light-emitting layer is used as a reference surface, then The difference between the depth of the above-mentioned strong light-emitting part from the above-mentioned reference surface and the depth of the above-mentioned weak light-emitting part from the above-mentioned reference surface is in the range of 0 to 1.0 μm.

12. The information code according to claim 10, Among them, If the outer surface of the above-mentioned light-emitting layer is used as a reference surface, then The difference between the depth of the above-mentioned strong light-emitting part from the above-mentioned reference surface and the depth of the above-mentioned weak light-emitting part from the above-mentioned reference surface is in the range of 0 to 0.2 μm.

13. The information code according to any one of claims 10 to 12, Among them, If the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the color value in the converted grayscale image of the captured image of the above-mentioned light-emitting layer is defined as the color intensity, then The value obtained by subtracting the above-mentioned color intensity of the above-mentioned weak light-emitting part from the above-mentioned color intensity of the above-mentioned strong light-emitting part is 30 or more.

14. The information code according to any one of claims 10 to 12, Among them, If the value corresponding to black is set to 1, the value corresponding to white is set to 100, and the color value in the converted grayscale image of the captured image of the above-mentioned light-emitting layer is defined as the color intensity, then The value obtained by subtracting the above-mentioned color intensity of the above-mentioned weak light-emitting part from the above-mentioned color intensity of the above-mentioned strong light-emitting part is 35 or more.

Images