Recording medium, drawing method, and drawing system

Abstract

Provided is a recording medium on which intended drawing can be performed.　The recording medium includes: a first recording layer configured such that drawing can be effected thereon using a first laser beam having a first peak wavelength; and a second recording layer configured such that drawing can be effected thereon using a second laser beam having a second peak wavelength different from the first peak wavelength. The first recording layer is configured to be capable of developing color by means of the first laser beam, and has a first color-developing layer containing a first leuco dye. The first recording layer and the second recording layer employ different recording systems. At least a portion of the first recording layer and the second recording layer overlap in a thickness direction of the recording medium.

Description

Recording medium, drawing method, and drawing system

[0001] The present disclosure relates to a recording medium, a drawing method, and a drawing system.

[0002] In recent years, recording media having a first recording layer and a second recording layer that use different recording methods have been studied. For example, Patent Document 1 describes a laminate that includes a laminate film colored cyan (C), magenta (M), and yellow (Y) by pigments, and a near-infrared laser marking layer for compensating for the gradation.

[0003] International Publication No. 2019 / 129527

[0004] However, with conventional recording media having a first recording layer and a second recording layer that use different recording methods, it may not be possible to perform intended drawing.

[0005] An object of the present disclosure is to provide a recording medium, a drawing method, and a drawing system that enable intended drawing to be performed.

[0006] In order to solve the above-mentioned problems, the recording medium according to the present disclosure comprises: a first recording layer configured to be able to draw with a first laser beam having a first peak wavelength; and a second recording layer configured to be able to draw with a second laser beam having a second peak wavelength different from the first peak wavelength; the first recording layer is configured to be able to develop color with the first laser beam and has a first color-developing layer containing a first leuco dye; the first recording layer and the second recording layer have different recording methods; and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium.

[0007] The drawing method according to the present disclosure includes: irradiating a first recording layer of a recording medium with a first laser beam having a first peak wavelength to draw a first image; and irradiating a second recording layer of the recording medium with a second laser beam having a second peak wavelength different from the first peak wavelength to draw a second image; the first recording layer is configured to be colorable by the first laser beam and has a first color-producing layer containing a first leuco dye; the first recording layer and the second recording layer have different recording methods; and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium.

[0008] The drawing system according to the present disclosure includes a first irradiation device capable of irradiating a first laser beam having a first peak wavelength; a second irradiation device capable of irradiating a second laser beam having a second peak wavelength different from the first peak wavelength; and a control device capable of controlling the first irradiation device and the second irradiation device, wherein the control device irradiates a first recording layer of a recording medium with the first laser beam to cause a first leuco dye contained in a first color-developing layer of the first recording layer to develop color, thereby drawing a first image; and irradiates a second recording layer of the recording medium with the second laser beam to draw a second image.

[0009] FIG. 1 is a perspective view of a recording medium according to a first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view of a recording layer. FIG. 4 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. FIG. 5 is a block diagram of a drawing system. FIG. 6 is a flowchart for explaining an example of a method for generating a first drawing setting file. FIG. 7 is a flowchart for explaining an example of a method for generating a second drawing setting file. FIG. 8 is a flowchart for explaining an example of a drawing method. FIG. 9 is a cross-sectional view of a recording medium according to a second embodiment of the present disclosure. FIG. 10 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. FIGS. 11A and 11B are diagrams for explaining an example of a drawing method. FIG. 12 is a diagram for explaining an example of an image method. FIG. 13 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. FIG. 14 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. FIG. 15 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. Fig. 16 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. Fig. 17 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. Fig. 18 is a schematic diagram of a first image, a second image, a visible image, and an infrared image. Fig. 19 is a cross-sectional view of a recording medium according to a modified example. Fig. 20 is a cross-sectional view of a recording medium according to a modified example. Fig. 21 is a cross-sectional view of a recording medium according to a modified example. Fig. 22 is a cross-sectional view of a first modified example of an intermediate layer. Fig. 23 is a cross-sectional view of a second modified example of an intermediate layer.

[0010] The embodiments of the present disclosure will be described in the following order. Note that in all the drawings of the following embodiments, the same or corresponding parts are denoted by the same reference numerals. 1. General description of recording medium according to the present disclosure 2. First embodiment (example of recording medium) 2.1 Configuration of recording medium 2.2 Method of manufacturing recording medium 2.3 Configuration of drawing system 2.4 Method of generating first drawing setting file 2.5 Method of generating second drawing setting file 2.6 Method of drawing on recording medium 2.7 Actions and effects 3. Second embodiment (example of recording medium) 3.1 Configuration of recording medium 3.2 Actions and effects 4. Modifications

[0011] <1 General Description of Recording Medium According to the Present Disclosure> The recording medium according to the present disclosure comprises a first recording layer configured to be able to be drawn with a first laser beam having a first peak wavelength, and a second recording layer configured to be able to be drawn with a second laser beam having a second peak wavelength different from the first peak wavelength, the first recording layer being configured to be able to develop color with the first laser beam and having a first color-developing layer containing a first leuco dye, the first recording layer and the second recording layer having different recording methods, and at least a portion of the first recording layer and the second recording layer overlapping in the thickness direction of the recording medium.

[0012] In conventional recording media, the drawing conditions (wavelength) of the laser light for the first recording layer and the second recording layer are the same, so if at least a portion of the first recording layer and the second recording layer overlap, when drawing on one of the first recording layer and the second recording layer, the other recording layer may be unintentionally drawn. In contrast, in the recording medium according to the present disclosure, the drawing conditions (wavelength) of the laser light for the first recording layer and the second recording layer are different, so even if at least a portion of the first recording layer and the second recording layer overlap, when drawing on one of the first recording layer and the second recording layer, it is possible to prevent the other recording layer from being unintentionally drawn.

[0013] In the recording medium according to the present disclosure, at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium, so that a first image drawn on the first recording layer and a second image drawn on the second recording layer can be superimposed. This allows the second image to be used to determine the authenticity of the recording medium. Furthermore, a composite image can be formed from the first image and the second image.

[0014] In order to enhance the security of the recording medium, it is preferable that a first image that is visible under visible light is drawn on the first recording layer, and a second image that can be captured under irradiation with light other than visible light is drawn on the second recording layer, and the first and second images are superimposed on each other. Here, examples of light other than visible light include ultraviolet light and infrared light, but the most commonly used imaging method is infrared light.

[0015] However, because the first recording layer remains translucent to visible light even after the first image is drawn, if a second recording layer is provided behind the first recording layer, the second image may be visible behind the first image. In this case, the visibility of the first image on the first recording layer may be reduced, and the display quality of the recording medium may be reduced. Specifically, for example, if the first image is a multicolor image such as a full-color image and the second image is a monochrome image (single-color image) such as black or brown, the colored portions of the first image may be difficult to see, or the first image may appear dark, which may reduce the display quality of the recording medium.

[0016] On the other hand, when a second recording layer is provided on the front surface side of the first recording layer, the first image on the first recording layer is covered by the second image on the second recording layer, which may result in a deterioration in the display quality of the recording medium. Specifically, for example, when the first image is a multicolor image such as a full-color image and the second image is a monochrome image (single-color image) such as black or brown, the first image, which is a multicolor image, is concealed by the second image, which is a monochrome image, which may result in a deterioration in the display quality of the recording medium.

[0017] To suppress the degradation of display quality, the second image preferably includes a portion of the first image. When the second image includes a portion of the first image, the overlapping portion between the first image and the second image can be reduced. Therefore, when the second recording layer is provided on the rear side of the first recording layer, the second image can be prevented from being viewed behind the first image. On the other hand, when the second recording layer is provided on the front side of the first recording layer, the first image on the first recording layer can be prevented from being covered by the second image on the second recording layer. Therefore, the degradation of display quality of the recording medium can be suppressed. The second image preferably includes, as a portion of the first image, at least one selected from the group consisting of the outline of the first image, a color portion of the first image having a predetermined color density or higher, and a background portion of the first image. The color portion of the first image having a predetermined color density or higher may include a substantially maximum color density portion of the first image or a black portion of the first image.

[0018] In the recording medium according to the present disclosure, the second recording layer is preferably configured to be capable of drawing a second image that is visible under visible light and can be captured under infrared light. This allows the authenticity of the recording medium to be determined by capturing an image of the recording medium with an imaging device and confirming the presence or absence of the second image drawn on the second recording layer. Furthermore, the authenticity of the recording medium can also be determined by capturing the second image drawn on the second recording layer with an imaging device and comparing it with a reference image. The reference image is, for example, the first image drawn on the first recording layer, an original image of the first image stored on a network such as a cloud server, or an original image of the first image stored in a terminal device.

[0019] In the recording medium according to the present disclosure, it is preferable that a first image visible under visible light is drawn on the first recording layer, a second image visible under visible light and imageable under infrared light is drawn on the second recording layer, the second image includes a portion of the first image, and a portion of the first image included in the second image overlaps with the first image on the first recording layer. This makes it possible to determine the authenticity of the recording medium by comparing the overlapping portions of the first and second images, i.e., the common portions of the first and second images.

[0020] In order to prevent a decrease in display quality of the recording medium due to overlapping of the first image and the second image, it is preferable that the portion of the first image includes at least one of the outline of the first image and a color portion of the first image that has a predetermined color density or higher. The color portion of the first image that has a predetermined color density or higher may include a portion of the first image that has a substantially maximum color density or a black portion of the first image. The portion of the first image may include the outline of the first image and a key plate portion of the first image.

[0021] In the recording medium according to the present disclosure, it is preferable that the first recording layer is provided above the second recording layer, and that at least a portion of the second image is concealed under visible light by the first image on the first recording layer. This makes it possible to determine the authenticity of the recording medium by capturing the second image under infrared light with an imaging device and confirming at least a portion of the concealed second image under visible light.

[0022] In the recording medium according to the present disclosure, it is preferable that a first image visible under visible light is drawn on the first recording layer, and a second image visible under visible light and imageable under infrared light is drawn on the second recording layer, and a composite image is formed from the first image and the second image. This allows the authenticity of the recording medium to be determined by capturing the composite image under infrared light with an imaging device and confirming the presence or absence of the second image. Furthermore, the authenticity of the recording medium can also be determined by capturing the composite image under infrared light with an imaging device and comparing it with a reference image. The reference image is, for example, the first image drawn on the first recording layer, an original image of the first image stored on a network such as a cloud server, or an original image of the first image stored in a terminal device.

[0023] When the first image and the second image form a composite image, the second image preferably includes at least one of a black portion of the composite image and a background portion of the composite image.

[0024] In the recording medium according to the present disclosure, it is preferable that the first color-forming layer further contains at least one selected from the group consisting of a matrix resin, a color developer, and a photothermal conversion agent, and it is more preferable that the first color-forming layer further contains a matrix resin, a color developer, and a photothermal conversion agent.

[0025] In the recording medium according to the present disclosure, the first recording layer is configured to be able to be written also by a third laser beam having a third peak wavelength and a fourth laser beam having a fourth peak wavelength, and the first recording layer further has a second color-producing layer configured to be able to develop color by irradiation with the third laser beam and containing a second leuco dye, and a third color-producing layer configured to be able to develop color by irradiation with the fourth laser beam and containing a third leuco dye, and it is preferable that the first peak wavelength, the second peak wavelength, the third peak wavelength, and the fourth peak wavelength are different from one another.

[0026] Since the first recording layer further includes the second color-forming layer and the third color-forming layer, a first image can be formed by the color-forming portions of the first color-forming layer, the second color-forming layer, and the third color-forming layer. Therefore, a multicolor image can be drawn on the first recording layer as the first image. For example, if the first color-forming layer, the second color-forming layer, and the third color-forming layer are configured to be capable of producing cyan, magenta, and yellow colors, respectively, a full-color image can be drawn on the first recording layer as the first image.

[0027] In the recording medium according to the present disclosure, it is preferable that the second color-forming layer and the third color-forming layer each independently further contain at least one selected from the group consisting of a matrix resin, a color developer, and a photothermal conversion agent, and it is more preferable that they further contain a matrix resin, a color developer, and a photothermal conversion agent.

[0028] In the recording medium according to the present disclosure, the first recording layer may be provided above the second recording layer, or the first recording layer may be provided below the second recording layer. In order to suppress a decrease in the display quality of the first image under visible light, it is preferable that the first recording layer be provided above the second recording layer. The recording medium may have a first surface on which the drawn first image and second image are visible, and a second surface opposite the first surface. The upper side may refer to the first surface side, and the lower side may refer to the second surface side.

[0029] In the recording medium according to the present disclosure, the first recording layer and the second recording layer may be in contact with each other, or may be spaced apart from each other. When the first recording layer and the second recording layer are in contact with each other, the first recording layer and the second recording layer may be fused together. When the first recording layer and the second recording layer are spaced apart, an adhesive layer or a bonding layer may be provided between the first recording layer and the second recording layer, or a light-transmitting or wavelength-selective intermediate layer may be provided between the first recording layer and the second recording layer. The light-transmitting intermediate layer may be, for example, an organic material layer, an inorganic material layer, or an organic-inorganic hybrid material layer. The wavelength-selective intermediate layer is preferably configured to reflect visible light and transmit infrared light. The wavelength-selective intermediate layer may be, for example, a dielectric multilayer film.

[0030] In the recording medium according to the present disclosure, from the viewpoint of improving the security of the recording medium, the peel strength between the layers constituting the recording medium is preferably 3.5 N / cm ２ More preferably, 5.0 N / cm ２ That's all.

[0031] In the recording medium according to the present disclosure, the area of ​​the first recording layer in a planar view and the area of ​​the second recording layer in a planar view may be substantially the same or different. When the areas of the first recording layer and the second recording layer are different, the area of ​​the first recording layer may be larger than the area of ​​the second recording layer, or the area of ​​the first recording layer may be smaller than the area of ​​the second recording layer.

[0032] The area of ​​the first recording layer in a planar view may be substantially the same as the area of ​​the recording medium in a planar view, or may be smaller than the area of ​​the recording medium in a planar view. The recording medium may further include a first base layer that houses the first recording layer, and the first base layer may have substantially the same area as the recording medium in a planar view. When the area of ​​the first recording layer is smaller than the area of ​​the recording medium, the first recording layer may be housed in a housing portion of the first base layer.

[0033] The area of ​​the second recording layer in a planar view may be substantially the same as the area of ​​the recording medium in a planar view, or may be smaller than the area of ​​the recording medium in a planar view. The recording medium may further include a second base layer that houses the second recording layer, and the second base layer may have substantially the same area as the recording medium in a planar view. When the area of ​​the second recording layer is smaller than the area of ​​the recording medium, the second recording layer may be housed in a housing portion of the second base layer.

[0034] In the recording medium according to the present disclosure, it is preferable that a reflective layer be further provided below the first recording layer and the second recording layer, from the viewpoint of improving the visibility of the first image and the second image.

[0035] The recording medium according to the present disclosure may further include at least one layer selected from the group consisting of a cover layer, an overlay layer, a protective layer, etc. The at least one layer is provided, for example, on at least one of the first surface side, the second surface side, and the side surface side of the recording medium.

[0036] The drawing method according to the present disclosure includes irradiating a first recording layer of a recording medium with a first laser beam having a first peak wavelength to draw a first image, and irradiating a second recording layer of the recording medium with a second laser beam having a second peak wavelength different from the first peak wavelength to draw a second image, wherein the first recording layer is configured to be colorable by the first laser beam and has a first color-forming layer containing a first leuco dye, the first recording layer and the second recording layer have different recording methods, and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium.

[0037] In the drawing method according to the present disclosure, the drawing conditions (wavelengths) of the laser light for the first recording layer and the second recording layer are different, so that even if the first recording layer and the second recording layer overlap, when drawing on one of the first recording layer and the second recording layer, it is possible to prevent the other recording layer from being unintentionally drawn.

[0038] In the drawing method of the present disclosure, the order of drawing the first image and the second image is not limited, and the second image may be drawn after the first image, or the first image may be drawn after the second image, or the first image and the second image may be drawn simultaneously.

[0039] In the drawing method of the present disclosure, it is preferable that the second image includes a portion of the first image, and the first image and the second image are drawn so that the portion of the first image included in the second image overlaps with the first image. This allows the second image to be used to determine the authenticity of the recording medium. Furthermore, a composite image can be formed from the first image and the second image.

[0040] Preferably, the drawing method of the present disclosure further includes extracting second image information for drawing the second image from first image information for drawing the first image, thereby allowing the first image and the second image to be drawn so that a portion of the first image overlaps with the second image.

[0041] Preferably, the rendering method of the present disclosure further includes correcting the first image information for rendering the first image so that the first image becomes brighter, thereby preventing the first image from appearing dark due to overlapping of the first and second images.

[0042] The drawing system according to the present disclosure includes a first irradiation device capable of irradiating a first laser beam having a first peak wavelength, a second irradiation device capable of irradiating a second laser beam having a second peak wavelength different from the first peak wavelength, and a control device capable of controlling the first irradiation device and the second irradiation device, wherein the control device irradiates a first recording layer of a recording medium with the first laser beam to cause a first leuco dye contained in a first color-developing layer of the first recording layer to develop color, thereby drawing a first image, and irradiates a second recording layer of the recording medium with the second laser beam to draw a second image.

[0043] In the drawing system of the present disclosure, the control device irradiates a first recording layer of the recording medium with a first laser light having a first peak wavelength, causing a first leuco dye contained in a first color-developing layer of the first recording layer to develop color, thereby drawing a first image, and irradiates a second recording layer of the recording medium with a second laser light having a second peak wavelength different from the first peak wavelength, thereby drawing a second image.Therefore, even if the first recording layer and the second recording layer overlap, when drawing on one of the first recording layer and the second recording layer, it is possible to prevent the other recording layer from being unintentionally drawn on.

[0044] In the drawing system of the present disclosure, the order of drawing the first image and the second image is not limited, and the control device may draw the second image after drawing the first image, or may draw the first image after drawing the second image, or may draw the first image and the second image simultaneously.

[0045] In the drawing system according to the present disclosure, the control device preferably further extracts second image information for drawing the second image from the first image information for drawing the first image, thereby allowing the first image and the second image to be drawn such that a portion of the first image overlaps with the second image.

[0046] In the drawing system according to the present disclosure, the control device preferably further corrects the first image information for drawing the first image so that the first image becomes brighter, thereby preventing the first image from appearing dark due to overlapping of the first and second images.

[0047] 2 First Embodiment [2.1 Configuration of Recording Medium] Fig. 1 is a perspective view of a recording medium 20 according to a first embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. The recording medium 20 includes, in order, a substrate 21, an under layer 22, an intermediate layer 23 including a recording layer (first recording layer) 10, and a recording layer (second recording layer) 24.

[0048] The substrate 21 and the under layer 22 may be bonded together by fusion or with an adhesive. The under layer 22 and the intermediate layer 23 may be bonded together by fusion or with an adhesive. The intermediate layer 23 and the recording layer 24 may be bonded together by fusion or with an adhesive.

[0049] The recording medium 20 may be a card such as a security card, a financial settlement card (e.g., a credit card, a cash card, etc.), an ID card (e.g., an employee ID card, a membership card, a student ID card, etc.), or a personal transaction card (e.g., a prepaid card, a point card, etc.). The recording medium 20 may be a sheet constituting a booklet such as a passport. The recording medium 20 may be a housing for an electronic device, etc.

[0050] The recording medium 20 has a drawing area R1 and a drawing area R2. The drawing area R1 is an area for drawing first information. The first information is, for example, image information such as a photograph of a face. In the first embodiment, an example will be described in which the image information is color image information. However, the image information is not limited to color image information, and may be single-color image information (monochrome image information). The drawing area R1 is an area in which information can be recorded on both the recording layer 10 and the recording layer 24.

[0051] The drawing area R2 is an area for drawing second information. The second information is, for example, text information. The second information may further include image information such as a design or a picture. The drawing area R2 is an area in which information can be recorded on the recording layer 24.

[0052] (Substrate 21) The substrate 21 is a support that supports the under layer 22, the intermediate layer 23, and the recording layer 24. The substrate 21 may be a card, a sheet, paper, a case, or the like. The substrate 21 may have a color such as white. The substrate 21 may have a design, a picture, a photograph, text, or a combination of two or more thereof (hereinafter referred to as a "design, etc.") printed on the surface on which the under layer 22, the intermediate layer 23, and the recording layer 24 are provided.

[0053] The substrate 21 includes, for example, plastic. The substrate 21 may include at least one selected from the group consisting of a colorant, an antistatic agent, a flame retardant, a surface modifier, and the like, as needed.

[0054] The plastic includes at least one selected from the group consisting of, for example, ester-based resins, amide-based resins, olefin-based resins, vinyl-based resins, acrylic-based resins, imide-based resins, styrene-based resins, engineering plastics, etc. When the substrate 21 includes two or more types of resins, the two or more types of resins may be mixed, copolymerized, or laminated.

[0055] The ester-based resin includes, for example, at least one selected from the group consisting of polyethylene terephthalate (PET)-based resin, polybutylene terephthalate (PBT)-based resin, polyethylene naphthalate (PEN)-based resin, polyethylene terephthalate-isophthalate copolymer-based resin, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer-based resin. The amide-based resin includes, for example, at least one selected from the group consisting of nylon 6-based resin, nylon 66-based resin, and nylon 610-based resin. The olefin-based resin includes, for example, at least one selected from the group consisting of polyethylene (PE)-based resin, polypropylene (PP)-based resin, and polymethylpentene (PMP)-based resin. The vinyl-based resin includes, for example, polyvinyl chloride (PVC)-based resin.

[0056] The acrylic resin includes, for example, at least one selected from the group consisting of polyacrylate resins, polymethacrylate resins, polymethyl methacrylate (PMMA) resins, etc. The imide resin includes, for example, at least one selected from the group consisting of polyimide (PI) resins, polyamideimide (PAI) resins, polyetherimide (PEI) resins, etc. The styrene resin includes, for example, at least one selected from the group consisting of polystyrene (PS) resins, high-impact polystyrene resins, acrylonitrile-styrene resins (AS resins), acrylonitrile-butadiene-styrene resins (ABS resins), etc. The engineering plastic includes, for example, at least one selected from the group consisting of polycarbonate (PC)-based resins, polyarylate (PAR)-based resins, polysulfone (PSF)-based resins, polyethersulfone (PES)-based resins, polyphenylene ether (PPE)-based resins, polyphenylene sulfide (PPS)-based resins, polyether ketone (PEK)-based resins, polyether-ether ketone (PEEK)-based resins, polyphenylene oxide (PPO)-based resins, and polyether sulfite-based resins.

[0057] (Underlayer 22) The underlayer 22 is provided between the substrate 21 and the intermediate layer 23. The underlayer 22 may be translucent to visible light. Examples of materials for the underlayer 22 include the same materials as those for the substrate 21. A pattern or the like may be printed on the underlayer 22.

[0058] (Intermediate layer 23) The intermediate layer 23 is provided between the under layer 22 and the recording layer 24. The intermediate layer 23 has a housing portion 23HL for housing the recording layer 10. Housing the recording layer 10 in the housing portion 23HL of the intermediate layer 23 can prevent a gap from being generated between the under layer 22 and the recording layer 24. The housing portion 23HL may be a through-hole that penetrates the intermediate layer 23 in the thickness direction. The housing portion 23HL may be configured so that the recording layer 10 can be fitted into it.

[0059] The intermediate layer 23 may have approximately the same thickness as the recording layer 10. The intermediate layer 23 may be in the form of a film. The intermediate layer 23 may be translucent to visible light. Examples of materials for the intermediate layer 23 include the same materials as those for the substrate 21.

[0060] (Recording Layer 10) The recording layer 10 is accommodated in the accommodation portion 23HL of the intermediate layer 23. The recording layer 10 has a peak wavelength λ １ Laser light L having １ , peak wavelength λ ２ Laser light L having ２ and peak wavelength λ ３ Laser light L having ３ The multicolor image can be visualized under visible light. １ The color of the first color-forming portion formed by irradiation with the laser light L ２ The color of the second color-forming portion formed by irradiation and the laser light L ３ The colors of the third color-forming portions formed by the irradiation of the third color-forming portions are different from each other. This makes it possible to draw a multicolor image on the recording layer 10.

[0061] In the first embodiment, an example will be described in which the multicolor image is a full-color image. The recording layer 10 is configured so that its color state can be changed by irradiation with laser light (external stimulus). This change in color state allows a full-color image to be drawn on the recording layer 10. The full-color image may be, for example, a photograph such as a face photo, a design or color pattern, or text such as letters or symbols. The full-color image may be composed of a combination of two or more of a photograph, a design, a color pattern, and text. The recording layer 10 and the recording layer 24 use different recording methods. At least a portion of the recording layer 10 and the recording layer 24 overlap in the thickness direction of the recording medium 20.

[0062] The change in coloring state may be a reversible change or an irreversible change. That is, the recording layer 10 may be rewritable, in which an image or the like can be rewritten, or may be write-once, in which an image or the like can be written only once. From the viewpoint of preventing tampering, it is preferable that the change in coloring state be an irreversible change.

[0063] 3 is a cross-sectional view of the recording layer 10. The recording layer 10 includes, in order, a substrate 11, an intermediate layer 12A, a color-forming layer 13A, an intermediate layer 12B, a color-forming layer 13B, an intermediate layer 12C, a color-forming layer 13C, an intermediate layer 12D, and a cover layer 14. Note that the intermediate layer 12A, the intermediate layer 12D, and the cover layer 14 are provided as needed. In this specification, when the intermediate layer 12A, the intermediate layer 12B, the intermediate layer 12C, and the intermediate layer 12D are referred to collectively without any particular distinction, they may be referred to as the intermediate layer 12. Similarly, when the color-forming layer 13A, the color-forming layer 13B, and the color-forming layer 13C are referred to collectively without any particular distinction, they may be referred to as the color-forming layer 13. One layer arbitrarily selected from coloring layers 13A, 13B, and 13C is an example of the first coloring layer in the claims, and the remaining two layers are examples of the second coloring layer and the third coloring layer in the claims. The recording layer 10 may be housed in the housing portion 23HL of the intermediate layer 23 so that the cover layer 14 faces the recording layer 24, or may be housed in the housing portion 23HL of the intermediate layer 23 so that the substrate 11 faces the recording layer 24. When the substrate 11 is not translucent to visible light, it is preferable that the cover layer 14 be housed in the housing portion 23HL of the intermediate layer 23 so that the cover layer 14 faces the recording layer 24.

[0064] (Substrate 11) The substrate 11 supports the intermediate layer 12A, the color-forming layer 13A, the intermediate layer 12B, the color-forming layer 13B, the intermediate layer 12C, the color-forming layer 13C, the intermediate layer 12D, and the cover layer 14. The substrate 11 is preferably made of a material that has excellent heat resistance and excellent dimensional stability in the in-plane direction of the substrate 11. The substrate 11 may be either translucent or opaque to visible light. In this specification, visible light refers to light in the wavelength range of 360 nm or more and 780 nm or less. The substrate 11 may have a predetermined color, such as white. The substrate 11 has, for example, a plate or film shape. In this disclosure, the term "film" is defined to include a sheet.

[0065] The substrate 11 may be, for example, rigid or flexible. When the substrate 11 is flexible, a flexible recording layer 10 can be realized. Examples of the rigid substrate 11 include a wafer or a glass substrate. Examples of the flexible substrate 11 include flexible glass, a film, or paper.

[0066] The substrate 11 includes, for example, at least one material selected from the group consisting of inorganic materials, metal materials, polymeric materials, etc. Examples of inorganic materials include silicon (Si), silicon oxide (SiO Ｘ ), silicon nitride (SiN Ｘ ) and aluminum oxide (AlO Ｘ ) and the like. Silicon oxide includes, for example, at least one selected from the group consisting of glass and spin-on glass (SOG). Metal materials include, for example, at least one selected from the group consisting of aluminum (Al), nickel (Ni), stainless steel, and the like. Polymer materials include, for example, at least one selected from the group consisting of polycarbonate (PC)-based resins, polyethylene terephthalate (PET)-based resins, polyethylene naphthalate (PEN)-based resins, polyethyl ether ketone (PEEK)-based resins, polyvinyl chloride (PVC)-based resins, and the like.

[0067] A reflective layer (not shown) may be provided on at least one of the first and second surfaces of the substrate 11, or the substrate 11 itself may also function as a reflective layer. Such a configuration of the substrate 11 enables a clearer color display.

[0068] (Coloring layers 13A, 13B, 13C) In a recorded state, the coloring layers 13A, 13B, and 13C are in a colored state, while in an unrecorded state, the coloring layers 13A, 13B, and 13C are in a decolored state. The coloring layers 13A, 13B, and 13C can be changed from a decolored state to a colored state by irradiation with laser light.

[0069] The coloring layers 13A, 13B, and 13C can each exhibit a different hue in the colored state. Specifically, the coloring layer 13A can exhibit magenta in the colored state. The coloring layer 13B can exhibit cyan in the colored state. The coloring layer 13C can exhibit yellow in the colored state. The magenta, cyan, and yellow colors are examples of the first, second, and third primary colors, respectively. The first, second, and third primary colors may be three primary colors. The first, second, and third primary colors may be colors other than magenta, cyan, and yellow. The laser light L capable of changing the coloring layer 13A into the colored state １ , laser light L capable of changing the color-producing layer 13B into a color-producing state. ２ and laser light L capable of changing the color-producing layer 13C into a color-producing state. ３ have different peak wavelengths.

[0070] The thicknesses of the color-forming layers 13A, 13B, and 13C are each independently preferably 1 μm or more and 20 μm or less, more preferably 2 μm or more and 15 μm or less. When the thicknesses of the color-forming layers 13A, 13B, and 13C are 1 μm or more, the color density can be improved. On the other hand, when the thicknesses of the color-forming layers 13A, 13B, and 13C are 20 μm or less, an increase in the amount of heat utilized by the color-forming layers 13A, 13B, and 13C can be suppressed, thereby suppressing deterioration of color development.

[0071] The color-producing layer 13A has a peak wavelength λ １ Laser light L having １ The color-forming layer 13A includes a first color-forming compound having electron-donating properties, a first color developer having electron-accepting properties, and a first photothermal conversion agent. The color-forming layer 13A preferably further includes a first matrix resin.

[0072] The color-producing layer 13B has a peak wavelength λ ２The color-forming layer 13B is configured to be capable of recording with a second laser beam having a second electron-donating property. The color-forming layer 13B contains a second color-forming compound having electron-accepting property, a second color developer having electron-accepting property, and a second photothermal conversion agent. The color-forming layer 13B preferably further contains a second matrix resin.

[0073] The color-producing layer 13C has a peak wavelength λ ３ The color-forming layer 13C is configured to be capable of recording with a third laser beam having a third electron-donating property. The color-forming layer 13C includes a third color-forming compound having electron-accepting property, a third color developer having electron-accepting property, and a third photothermal conversion agent. The color-forming layer 13C preferably further includes a third matrix resin.

[0074] Laser light L １ , laser light L ２ and laser light L ３ is preferably a near-infrared laser beam. １ , peak wavelength λ ２ and peak wavelength λ ３ The peak wavelength λ is preferably in the near infrared region. １ , peak wavelength λ ２ and peak wavelength λ ３ The upper limit of the peak wavelength λ is, for example, less than 1000 nm, preferably 915 nm or less. １ , peak wavelength λ ２ and peak wavelength λ ３ The lower limit is, for example, 760 nm or more.

[0075] Peak wavelength λ １ , peak wavelength λ ２ and peak wavelength λ ３ are different from each other. This allows the color-forming layers 13A, 13B, and 13C to independently develop colors. １ Laser light L having １ , peak wavelength λ ２ Laser light L having ２ and peak wavelength λ ３ Laser light L having ３One of the laser beams is an example of a first laser beam having a first peak wavelength in the claims, and the remaining two laser beams are examples of a third laser beam having a third peak wavelength and a fourth laser beam having a fourth peak wavelength in the claims.

[0076] (First color former, second color former, third color former) The first color former, second color former, and third color former are capable of developing colors by reacting with the first color former, second color former, and third color former, respectively. The first color former, second color former, and third color former are capable of developing different hues in a colored state. Specifically, the first color former is capable of developing magenta in a colored state. The second color former is capable of developing cyan in a colored state. The third color former is capable of developing yellow in a colored state.

[0077] The first color former, the second color former, and the third color former are, for example, leuco dyes. When a lactone ring in the leuco dye molecule reacts with an acid, the lactone ring opens and develops color. When the open lactone ring in the leuco dye reacts with a base, it may close and disappear. The leuco dye may be, for example, an existing dye for thermal paper.

[0078] The first color former, the second color former, and the third color former are not particularly limited and can be appropriately selected depending on the purpose. The first color former, the second color former, and the third color former each independently include at least one compound selected from the group consisting of, for example, fluoran-based compounds, triphenylmethanephthalide-based compounds, azaphthalide-based compounds, phenothiazine-based compounds, leucoauramine-based compounds, and indolinophthalide-based compounds. In addition, the first color former, the second color former and the third color former each independently include, for example, 2-anilino-3-methyl-6-diethylaminofluoran, 2-anilino-3-methyl-6-di(n-butylamino)fluoran, 2-anilino-3-methyl-6-(N-n-propyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-isopropyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-isobutyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-n-amyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-sec-butyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-n-amyl-N-ethylamino)fluoran, Fluoran, 2-anilino-3-methyl-6-(N-iso-amyl-N-ethylamino)fluoran, 2-anilino-3-methyl-6-(N-n-propyl-N-isopropylamino)fluoran, 2-anilino-3-methyl-6-(N-cyclohexyl-N-methylamino)fluoran, 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluoran, 2-anilino-3-methyl-6-(N-methyl-p-toluidino)fluoran, 2-(m-trichloromethylanilino)-3-methyl-6-diethylaminofluoran, 2-(m-trifluoromethylanilino)-3-methyl-6-diethylaminofluoran, 2-(m-trichloromethylanilino)-3-methyl-6-(N-cyclohexyl-N-methylamino)fluoran, 2-(2,4-dimethylanilino)-3-methyl-6-diethylaminofluoran, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-ethylanilino)fluoran, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-propyl-p-toluidino)fluoran, 2-anilino-6-(N-n-hexyl-N-ethylamino)fluoran, 2-(o-chloroanilino)-6-diethylaminofluoran, 2-(o-chloroanilino)-6-dibutylaminofluoran, 2-(m-trifluoromethylanilino)-6-diethylaminofluoran, 2,3-dimethyl-6-dimethylaminofluoran, 3-methyl-6-(N-ethyl-p-toluidino)fluoran, 2-chloro-6 -diethylaminofluoran, 2-bromo-6-diethylaminofluoran, 2-chloro-6-dipropylaminofluoran, 3-chloro-6-cyclohexylaminofluoran, 3-bromo-6-cyclohexylaminofluoran, 2-chloro-6-(N-ethyl-N-isoamylamino)fluoran, 2-chloro-3-methyl-6-diethylaminofluoran, 2-anilino-3-chloro-6-diethylaminofluoran, 2-(o-chloroanilino)-3-chloro-6-cyclohexylaminofluoran, 2-(m-trifluoromethylanilino)-3-chloro-6-diethylaminofluoran, 2-(2,3-dichloroanilino)-3-chloro-6-diethylaminofluoran, 1,2-benzo-6-diethylaminofluoran, 3-diethylamino-6-(m-trifluoromethylanilino)fluoran, 3-(1-ethyl-2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 3-(1-octyl- 2-methylindol-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide, 3-(1-ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide 3-(1-ethyl-2-methylindol-3-yl)-3-(4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindol-3-yl)-3-(4-N-n-amyl-N-methylaminophenyl)-4-azaphthalide, 3-(1-methyl-2-methylindol-3-yl)-3-(2-hexyloxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide nyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 2-(p-acetylanilino)-6-(N-n-amyl-N-n-butylamino)fluoran, 2-benzylamino-6-(N-ethyl-p-toluidino)fluoran, 2-benzylamino-6-(N-methyl-2,4-dimethylanilino)fluoran, 2-benzylamino-6-(N-ethyl-2,4-dimethylanilino)fluoran, 2-benzylamino-6-(N-methyl-p-toluidino)fluoran, 2-benzylamino-6-(N-ethyl-p-toluidino)fluoran, 2-(di-p-methylbenzylamino)-6-(N-ethyl-p-toluidino)fluoran, 2-(α-phenylethylamino)-6-(N-ethyl-p-toluidino)fluoran, 2-methylamino-6-(N-methylanilino)fluoran, 2-methylamino-6-(N-ethylanilino)fluoran, 2-methylamino-6-(N-propylanilino)fluoran , 2-ethylamino-6-(N-methyl-p-toluidino)fluoran, 2-methylamino-6-(N-methyl-2,4-dimethylanilino)fluoran, 2-ethylamino-6-(N-ethyl-2,4-dimethylanilino)fluoran, 2-dimethylamino-6-(N-methylanilino)fluoran, 2-dimethylamino-6-(N-ethylanilino)fluoran, 2-diethylamino-6-(N-methyl-p-toluidino)fluoran, 2-diethylamino-6-(N-ethyl-p-toluidino)fluoran, 2-dipropylamino-6-(N-methyl p-toluidino)fluoran, 2-dipropylamino-6-(N-ethylanilino)fluoran, 2-amino-6-(N-methylanilino)fluoran, 2-amino-6-(N-ethylanilino)fluoran, 2-amino-6-(N-propylanilino)fluoran, 2-amino-6-(N-methyl-p-toluidino)fluoran, 2-amino-6-(N-ethyl-p-toluidino)fluoran, 2-amino-6-(N-propyl-p-toluidino)fluoran, 2-amino-6-(N-methyl-p-ethylanilino)fluoran, 2-amino-6-(N-ethylanilino)fluoran 2-amino-6-(N-propyl-p-ethylanilino)fluoran, 2-amino-6-(N-methyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-ethyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-propyl-2,4-dimethylanilino)fluoran, 2-amino-6-(N-methyl-p-chloroanilino)fluoran, 2-amino-6-(N-ethyl-p-chloroanilino)fluoran, 2-amino-6-(N-propyl-p-chloroanilino)fluoran, 1,It may contain at least one selected from the group consisting of 2-benzo-6-(N-ethyl-N-isoamylamino)fluoran, 1,2-benzo-6-dibutylaminofluoran, 1,2-benzo-6-(N-methyl-N-cyclohexylamino)fluoran, and 1,2-benzo-6-(N-ethyl-N-toluidino)fluoran.

[0079] (First color developer, second color developer, third color developer) The first color developer, second color developer, and third color developer are capable of causing the first color former compound, second color former compound, and third color former compound in a decolorized state to develop color, respectively. The first color developer, second color developer, and third color developer may be the same type, or the first color developer, second color developer, and third color developer may be different types. The first color developer, second color developer, and third color developer are compounds containing an electron-accepting group in the molecule. The electron-accepting moiety of the first color developer, second color developer, and third color developer reacts with the lactone ring of the first color former compound, second color former compound, and third color former compound, respectively, opening the lactone ring, causing the first color former compound, second color former compound, and third color former compound to develop color. The first color developer, the second color developer, and the third color developer each independently contain at least one selected from the group consisting of, for example, phenol derivatives, salicylic acid derivatives, urea derivatives, etc. In the following description, when the first color developer, the second color developer, and the third color developer are referred to collectively without any particular distinction, they may be simply referred to as color developers.

[0080] Specifically, for example, the color developer contains a compound represented by the following formula (1). (However, in formula (1), X 0 is a divalent group containing at least one benzene ring. 01 , Y 02 are each independently a monovalent group. n01 and n02 are each independently an integer of 0 to 5. When n01 is an integer of 2 to 5, Y 01 may be the same or different. When n02 is an integer of 2 to 5, Y 02 may be the same or different. 01 , Z 02are each independently a hydrogen-bonding group.

[0081] X 0 contains at least one benzene ring, 0 Since the melting point can be made higher than when X is an aliphatic hydrocarbon group (for example, a normal alkyl chain), the color retention properties during storage at high temperature and high humidity (hereinafter referred to as "high temperature and high humidity storage properties") can be improved. 0 Preferably, the compound has at least two benzene rings. The high-temperature, high-humidity storage characteristics are, for example, storage characteristics under an environment of 80°C and 60% RH. Improved heat resistance improves the resistance of the recording layer 10 to harsh processes (for example, hot pressing or integral molding using molten resin, etc.). 0 When contains at least two benzene rings, the at least two benzene rings may be condensed, for example, naphthalene or anthracene.

[0082] Z 01 , Z 02 are each independently a hydrogen-bonding group, the color developers tend to exist in a state of being aggregated together to some extent via hydrogen bonds, thereby improving the stability of the color developer in the color-forming layer 13. In this specification, the hydrogen-bonding group means a functional group containing an atom that can form a hydrogen bond with another functional group or an atom present in another compound, etc.

[0083] The color developer preferably contains a compound represented by the following formula (2): (However, in formula (2), X 1 is a divalent group containing at least one benzene ring. 11 , Y 12 , Y 13 , Y 14 are each independently a monovalent group. 11 , Z 12 are each independently a hydrogen-bonding group.

[0084] X 1 contains at least one benzene ring, 1In comparison with the case where X is an aliphatic hydrocarbon group (for example, a normal alkyl chain), the melting point can be made higher, and therefore the high-temperature, high-humidity storage properties can be improved. 1 Preferably, X contains at least two benzene rings. 1 When contains at least two benzene rings, the at least two benzene rings may be condensed, for example, naphthalene or anthracene.

[0085] Z 11 , Z 12 are each independently a hydrogen-bonding group, the color developers tend to exist in a state of being solidified to some extent via hydrogen bonds, and the stability of the color developers in the color-forming layer 13 is improved.

[0086] When formula (1) and formula (2) contain a hydrocarbon group, the hydrocarbon group is a general term for a group composed of carbon (C) and hydrogen (H), and may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. A saturated hydrocarbon group is an aliphatic hydrocarbon group that does not have a carbon-carbon multiple bond, and an unsaturated hydrocarbon group is an aliphatic hydrocarbon group that has a carbon-carbon multiple bond (a carbon-carbon double bond or a carbon-carbon triple bond).

[0087] When Formula (1) and Formula (2) contain a hydrocarbon group, the hydrocarbon group may be a chain or may contain one or more rings. The chain may be a straight chain or a branched chain having one or more side chains.

[0088] (X containing one benzene ring 0 , X １ ) X in formula (1) 0 and X in formula (2) 1 is, for example, a divalent group containing one benzene ring. The divalent group is, for example, represented by the following formula (3): (However, in formula (3), X 21 It doesn't matter if it's there or not, X 21 If there is X 21 is a divalent group. 22 It doesn't matter if it's there or not, X 22 If there is X 22is a divalent group. 21 is a monovalent group. n21 is an integer of 0 to 4. When n21 is an integer of 2 to 4, R 21 may be the same or different. * indicates a bond.)

[0089] In formula (3), X to the benzene ring 21 and X 22 The bonding position of X to the benzene ring is not limited. 21 and X 22 The bonding position may be any of the ortho, meta and para positions.

[0090] The divalent group containing one benzene ring is preferably represented by the following formula (4) from the viewpoint of improving high-temperature, high-humidity storage properties. (However, in formula (4), R 22 is a monovalent group. n22 is an integer of 0 to 4. When n22 is an integer of 2 to 4, R 22 may be the same or different. * indicates a bond.)

[0091] X in formula (1) 0 is a divalent group containing one benzene ring, in formula (4), Z 01 and Z 02 The bonding position of Z to the benzene ring is not limited. 01 and Z 02 The bonding position may be any of the ortho, meta and para positions.

[0092] X in formula (2) 1 is a divalent group containing one benzene ring, in formula (4), Z 11 and Z 12 The bonding position of Z to the benzene ring is not limited. 11 and Z 12 The bonding position may be any of the ortho, meta and para positions.

[0093] (X 21 , X 22) X in formula (3) 21 , X 22 are each independently a divalent group and are not particularly limited, but an example is a hydrocarbon group which may have a substituent. The hydrocarbon group is preferably chain-like. When the hydrocarbon group is chain-like, the melting point of the color developer can be lowered, so that the color developer melts upon irradiation with laser light, making it easier for the color former to develop color. From the viewpoint of lowering the melting point of the color developer, a normal alkyl chain is particularly preferred among chain-like hydrocarbon groups.

[0094] The hydrocarbon group which may have a substituent has, for example, 1 to 15 carbon atoms, 1 to 13 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 3 carbon atoms.

[0095] X in formula (3) 21 , X 22 When is a normal alkyl group, the number of carbon atoms in the normal alkyl group is preferably 8 or less, more preferably 6 or less, even more preferably 5 or less, and particularly preferably 3 or less, from the viewpoint of high-temperature storage stability. When the normal alkyl group has 8 or less carbon atoms, the normal alkyl group is short in length, so that thermal disturbance is unlikely to occur in the color developer during high-temperature storage, and it is thought that the site that interacted with the color former such as a leuco dye during color development is unlikely to be dissociated. Therefore, the color former such as a leuco dye is unlikely to fade during high-temperature storage, improving high-temperature storage stability.

[0096] Examples of the substituent that the hydrocarbon group may have include a halogen group (e.g., a fluorine group) or an alkyl group having a halogen group (e.g., a fluorine group), etc. The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms contained in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0097] (R 21 ) R in formula (3) 21 is not particularly limited as long as it is a monovalent group, but examples thereof include a halogen group or a hydrocarbon group which may have a substituent.

[0098] The halogen group is, for example, a fluorine group (--F), a chlorine group (--Cl), a bromine group (--Br), or an iodine group (--I).

[0099] The hydrocarbon group which may have a substituent has, for example, 1 to 15 carbon atoms, 1 to 13 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 3 carbon atoms.

[0100] Examples of the substituent that the hydrocarbon group may have include a halogen group (e.g., a fluorine group) or an alkyl group having a halogen group (e.g., a fluorine group), etc. The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms contained in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0101] (R 22 ) R in formula (4) 22 is not particularly limited as long as it is a monovalent group, but examples thereof include a halogen group and a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are respectively represented by R 21 is the same as:

[0102] (X containing two benzene rings 0 , X 1 ) X in formula (1) 0 and X in formula (2) 1 is, for example, a divalent group containing two benzene rings. The divalent group is, for example, represented by the following formula (5): (However, in formula (5), X 31 It doesn't matter if it's there or not, X 31 If there is X 31 is a divalent group. 32 It doesn't matter if it's there or not, X 32 If there is X 32 is a divalent group. 33 It doesn't matter if it's there or not, X 33 If there is X 33 is a divalent group. 31 , R 32are each independently a monovalent group. n31 and n32 are each independently an integer of 0 to 4. When n31 is an integer of 2 to 4, R 31 may be the same or different. When n32 is an integer of 2 to 4, R 32 may be the same or different. * indicates a bond.)

[0103] In formula (5), X to the benzene ring 31 and X 32 The bonding position of X to the benzene ring is not limited. 31 and X 32 The bonding position of X to the benzene ring in formula (5) may be any of the ortho, meta and para positions. 32 and X 33 The bonding position of X to the benzene ring is not limited. 32 and X 33 The bonding position may be any of the ortho, meta and para positions.

[0104] The divalent group containing two benzene rings is preferably represented by the following formula (6) from the viewpoint of improving high-temperature, high-humidity storage properties. (However, in formula (6), X 34 is a divalent group. 33 , R 34 are each independently a monovalent group. n33 and n34 are each independently an integer of 0 to 4. When n33 is an integer of 2 to 4, R 33 may be the same or different. When n34 is an integer of 2 to 4, R 34 may be the same or different. * indicates a bond.)

[0105] X in formula (1) 0 is a divalent group containing two benzene rings, Z 01 and X 34 The bonding position of Z to the benzene ring is not limited. 01and X 34 The bonding position of may be any of the ortho, meta and para positions. 02 and X 34 The bonding position of Z to the benzene ring is not limited. 02 and X 34 The bonding position may be any of the ortho, meta and para positions.

[0106] X in formula (2) 1 is a divalent group containing two benzene rings, Z 11 and X 34 The bonding position of Z to the benzene ring is not limited. 11 and X 34 The bonding position of may be any of the ortho, meta and para positions. 12 and X 34 The bonding position of Z to the benzene ring is not limited. 12 and X 34 The bonding position may be any of the ortho, meta and para positions.

[0107] (X 31 , X 32 , X 33 ) X in formula (5) 31 , X 32 , X 33 are each independently a divalent group, and are not particularly limited, but an example thereof is a hydrocarbon group which may have a substituent. 21 , X 22 is the same as:

[0108] (X 34 ) X in formula (6) 34 is not particularly limited as long as it is a divalent group, but an example thereof is a hydrocarbon group which may have a substituent. The hydrocarbon group is the X in the above formula (3). 21 , X 22 is the same as:

[0109] (R31 , R 32 ) R in formula (5) 31 , R 32 is not particularly limited as long as it is a monovalent group, but examples thereof include a halogen group and a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are each represented by R in the above formula (3). 21 is the same as:

[0110] (R 33 , R 34 ) R in formula (6) 33 , R 34 is not particularly limited as long as it is a monovalent group, but examples thereof include a halogen group and a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are each represented by R in the above formula (3). 21 is the same as:

[0111] (Y 01 , Y 02 ) Y in formula (1) 01 , Y 02 are each independently, for example, a hydrogen group (-H), a hydroxy group (-OH), a halogen group (-X), a carboxy group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent.

[0112] The halogen group is, for example, a fluorine group (--F), a chlorine group (--Cl), a bromine group (--Br), or an iodine group (--I).

[0113] The hydrocarbon group which may have a substituent has, for example, 1 to 15 carbon atoms, 1 to 13 carbon atoms, 1 to 12 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 3 carbon atoms.

[0114] Examples of the substituent that the hydrocarbon group may have include a halogen group (e.g., a fluorine group) or an alkyl group having a halogen group (e.g., a fluorine group), etc. The hydrocarbon group that may have a substituent may be one in which some of the carbon atoms of the hydrocarbon group (e.g., some of the carbon atoms contained in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0115] In formula (1), (Y01 ) n01 and / or (Y 02 ) n02 It is preferred that one of the groups Y is a hydroxy group (—OH). 01 ) n01 and / or (Y 02 ) n02 When one of the groups is a hydroxy group (—OH), the display quality and light resistance can be improved.

[0116] (Y 11 , Y 12 , Y 13 , Y 14 In formula (2), Y relative to the benzene ring 11 and Y 12 The bonding position of Y to the benzene ring is not limited. 11 and Y 12 The bonding position of Y may be any of the ortho, meta and para positions. 13 and Y 14 The bonding position of Y to the benzene ring is not limited. 13 and Y 14 The bonding position of Y to one benzene may be any of the ortho, meta and para positions. 11 and Y 12 and the bonding position of Y to the other benzene 13 and Y 14 may be the same as or different from the binding position of

[0117] Y in formula (2) 11 , Y 12 , Y 13 , Y 14 are each independently, for example, a hydrogen group (-H), a hydroxy group (-OH), a halogen group, a carboxy group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have a substituent. The halogen group and the hydrocarbon group which may have a substituent are each represented by Y 01 , Y 02 is the same as:

[0118] In formula (2), Y 11 and / or Y 13 is preferably a hydroxy group (—OH). 11 and / or Y 13 When the group is a hydroxy group (—OH), the display quality and light resistance can be improved.

[0119] (Z 01 , Z 02 ) Z in formula (1) 01 , Z 02 are each independently, for example, a urea bond (-NHCONH-), an amide bond (-NHCO-, -OCHN-) or a hydrazide bond (-NHCOCONH-). 01 , Z 02 is preferably a urea bond. 01 When Z is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 02 is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0120] (Z 11 , Z 12 ) Z in formula (2) 11 , Z 12 are each independently, for example, a urea bond (-NHCONH-), an amide bond (-NHCO-, -OCHN-) or a hydrazide bond (-NHCOCONH-). 11 , Z 12 is preferably a urea bond. 11 When Z is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene. 12 is an amide bond, the nitrogen contained in the amide bond may be bonded to benzene, or the carbon contained in the amide bond may be bonded to benzene.

[0121] (Specific examples of color developers) X in formula (1) 0 and X in formula (2) 1 Specifically, the color developer containing one benzene ring includes at least one selected from the group consisting of compounds represented by the following formulas (7-1) to (7-6).

[0122] X in formula (1) 0 and X in formula (2) 1 Specifically, the color developer containing two benzene rings includes at least one selected from the group consisting of compounds represented by the following formulas (8-1) to (8-8).

[0123] (First photothermal conversion agent, second photothermal conversion agent, third photothermal conversion agent) The first photothermal conversion agent, second photothermal conversion agent, and third photothermal conversion agent are capable of absorbing light in a predetermined wavelength range, such as the near-infrared region, and generating heat. The first photothermal conversion agent, second photothermal conversion agent, and third photothermal conversion agent have different absorption wavelength peaks. Specifically, the first photothermal conversion agent has an absorption wavelength peak at approximately λ １ The second photothermal conversion agent has an absorption wavelength peak at about wavelength λ ２ The third photothermal conversion agent has an absorption wavelength peak at about wavelength λ ３ It has an absorption wavelength peak at wavelength λ １ , λ ２ , λ ３ are different from each other. The absorption wavelength peak is preferably in the near-infrared region. The near-infrared region is, for example, a wavelength range of 700 nm or more and 2000 nm or less. As described above, the first photothermal conversion agent, the second photothermal conversion agent, and the third photothermal conversion agent have different absorption wavelength peaks from each other, so that a desired layer among the color-forming layers 13A, 13B, and 13C can be selectively colored by irradiation with laser light. It is preferable to use a near-infrared absorbing dye that has almost no absorption in the visible region as the first photothermal conversion agent, the second photothermal conversion agent, and the third photothermal conversion agent.

[0124] The first photothermal conversion agent, the second photothermal conversion agent, and the third photothermal conversion agent each independently include at least one selected from the group consisting of, for example, compounds having a phthalocyanine skeleton (phthalocyanine dyes), compounds having a squarylium skeleton (squarylium dyes), and inorganic compounds.

[0125] The inorganic compound may include at least one selected from the group consisting of metal complexes such as dithio complexes, diimonium salts, aminium salts, graphite, carbon black, metal powder particles, metal oxides such as tricobalt tetroxide, iron oxide, chromium oxide, copper oxide, titanium black, and ITO (indium tin oxide), metal nitrides such as niobium nitride, metal carbides such as tantalum carbide, metal sulfides, and various magnetic powders. In addition, the inorganic compound may include a compound (cyanine dye) having a cyanine skeleton with excellent light resistance and heat resistance. Here, excellent light resistance means that the compound does not decompose under the usage environment, for example, when irradiated with light from a fluorescent lamp. Excellent heat resistance means that the maximum absorption peak value of the absorption spectrum does not change by 20% or more, for example, when the compound is formed into a film together with a polymer material and stored at 150°C for 30 minutes. Examples of such compounds having a cyanine skeleton include compounds containing SbF in the molecule. ６ , P.F. ６ , B.F. ４ , ClO ４ , C.F. ３ SO ３ and (CF ３ SO ３ ) ２ and at least one of a counter ion of N and a methine chain containing a five-membered ring or a six-membered ring. The compound having a cyanine skeleton used in the recording layer 10 in the first embodiment preferably has both one of the counter ions and a cyclic structure such as a five-membered ring or a six-membered ring in the methine chain, but sufficient light resistance and heat resistance are ensured as long as it has at least one of them.

[0126] (First matrix resin, second matrix resin, third matrix resin) The first matrix resin, second matrix resin, and third matrix resin preferably function as a binder. The first matrix resin is preferably one in which the first color former, first color developer, and first photothermal conversion agent are easily and homogeneously dispersed. The second matrix resin is preferably one in which the second color former, second color developer, and second photothermal conversion agent are easily and homogeneously dispersed. The third matrix resin is preferably one in which the third color former, third color developer, and third photothermal conversion agent are easily and homogeneously dispersed. The first matrix resin, second matrix resin, and third matrix resin may be of the same type, or may be of different types.

[0127] The first matrix resin, the second matrix resin, and the third matrix resin each independently contain at least one resin selected from the group consisting of, for example, thermosetting resins and thermoplastic resins. The first matrix resin, the second matrix resin, and the third matrix resin preferably contain a polycarbonate-based resin. By including the first matrix resin, the second matrix resin, and the third matrix resin in the polycarbonate-based resin, the light resistance of the background of the recording layer 10 can be improved. Here, a polycarbonate-based resin is a resin having at least a carbonate group (—O—(C═O)—O—) as a structural unit in the main chain. Therefore, the main chain may contain other structural units in addition to the carbonate group.

[0128] The first matrix resin, the second matrix resin, and the third matrix resin may each independently contain, instead of or together with the polycarbonate-based resin, at least one selected from the group consisting of polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethyl cellulose, polystyrene, styrene-based copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polyacrylic acid ester, polymethacrylic acid ester, acrylic acid-based copolymer, maleic acid-based polymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethyl cellulose, carboxymethyl cellulose, starch, and the like.

[0129] (Additive) The color-forming layer 13A, the color-forming layer 13B, and the color-forming layer 13C may further contain, as necessary, at least one additive selected from the group consisting of a sensitizer, an ultraviolet absorber, etc. From the viewpoint of suppressing coloration of the background, the color-forming layer 13A, the color-forming layer 13B, and the color-forming layer 13C preferably contain an amine-based compound.

[0130] When the color-forming layers 13A, 13B, and 13C contain an amine compound, the color-forming layers 13A, 13B, and 13C preferably contain, together with the amine compound, at least one compound selected from the group consisting of epoxy compounds and carbodiimide compounds. If the color-forming layers 13A, 13B, and 13C contain an amine compound, there is a risk that the reliability of the color-forming portion will decrease during storage at high temperature and high humidity. However, if the color-forming layers 13A, 13B, and 13C contain, together with the amine compound, at least one compound selected from the group consisting of epoxy compounds and carbodiimide compounds, the decrease in reliability of the color-forming portion during storage at high temperature and high humidity due to the amine compound can be suppressed.

[0131] (Intermediate layer 12A, intermediate layer 12B, intermediate layer 12C, intermediate layer 12D) The intermediate layer 12A is provided between the substrate 11 and the color-forming layer 13A. The intermediate layer 12A can provide heat insulation between the substrate 11 and the color-forming layer 13A and can suppress diffusion of the constituent materials between the substrate 11 and the color-forming layer 13A. The intermediate layer 12B is provided between the color-forming layer 13A and the color-forming layer 13B. The intermediate layer 12B can provide heat insulation between the color-forming layer 13A and the color-forming layer 13B and can suppress diffusion of the constituent materials between the color-forming layer 13A and the color-forming layer 13B. The intermediate layer 12C is provided between the color-forming layer 13B and the color-forming layer 13C. The intermediate layer 12C can provide heat insulation between the color-forming layer 13B and the color-forming layer 13C and can suppress diffusion of the constituent materials between the color-forming layer 13B and the color-forming layer 13C. The intermediate layer 12D is provided between the color-forming layer 13C and the cover layer 14. The intermediate layer 12D can insulate the color-forming layer 13C from the cover layer 14 and can also suppress diffusion of the constituent materials between the color-forming layer 13C and the cover layer 14.

[0132] The intermediate layer 12A may be translucent or non-translucent to the laser light and visible light used to draw on the recording layer 10. The intermediate layers 12B, 12C, and 12D are translucent to the laser light and visible light used to draw on the recording layer 10.

[0133] The thicknesses of the intermediate layers 12A, 12B, 12C, and 12D are each independently preferably 3 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less. When the thicknesses of the intermediate layers 12A, 12B, 12C, and 12D are 3 μm or more, sufficient heat insulating effect and sufficient diffusion suppression effect can be obtained. On the other hand, when the thicknesses of the intermediate layers 12A, 12B, 12C, and 12D are 100 μm or less, a decrease in translucency to visible light can be suppressed. Furthermore, a decrease in the bending resistance of the recording layer 10 can be suppressed, making it less likely for defects such as cracks to occur. The thicknesses of the intermediate layers 12A, 12B, 12C, and 12D may be the same or different from each other.

[0134] The intermediate layer 12A is an adhesive layer 12A. １ and the ultraviolet curing resin layer 12A. ２ and the adhesive layer 12A are provided in this order on the substrate 11. １ The substrate 11 and the ultraviolet curable resin layer 12A ２ The adhesive layer 12A is adhered to the substrate. １ The ultraviolet curing resin layer 12A may be capable of insulating the space between the substrate 11 and the color-forming layer 13A. ２ The adhesive layer 12A can insulate the space between the substrate 11 and the color-forming layer 13A and can suppress the diffusion of constituent materials (for example, the first color-forming compound) between the substrate 11 and the color-forming layer 13A. １ and the ultraviolet curing resin layer 12A ２ The order of lamination of these layers is not limited to the above example, and the order of lamination of these layers may be reversed from the above order of lamination.

[0135] The intermediate layer 12B is an adhesive layer 12B １ and the ultraviolet curing resin layer 12B. ２ The adhesive layer 12B is provided on the color-developing layer 13A in this order. １ The coloring layer 13A and the ultraviolet curing resin layer 12B ２ Adhesive layer 12B １ The ultraviolet curing resin layer 12B may be capable of insulating the coloring layer 13A from the coloring layer 13B. ２ The adhesive layer 12B can insulate the color-forming layer 13A from the color-forming layer 13B and can suppress the diffusion of the constituent materials (e.g., the first color-forming compound, the second color-forming compound, etc.) between the color-forming layer 13A and the color-forming layer 13B. １ and the ultraviolet curing resin layer 12B ２ The order of lamination of these layers is not limited to the above example, and the order of lamination of these layers may be reversed from the above order of lamination.

[0136] The intermediate layer 12C is an adhesive layer 12C. １ and the ultraviolet curing resin layer 12C. ２ and an adhesive layer 12C are provided in this order on the color-developing layer 13B. １ The coloring layer 13B and the ultraviolet curing resin layer 12C ２ Adhesive layer 12C １The ultraviolet curing resin layer 12C may be capable of insulating the coloring layer 13B from the coloring layer 13C. ２ The adhesive layer 12C can insulate the color-forming layer 13B from the color-forming layer 13C, and can suppress the diffusion of the constituent materials (e.g., the second and third color-forming compounds) between the color-forming layer 13B and the color-forming layer 13C. １ and the ultraviolet curing resin layer 12C ２ The order of lamination of these layers is not limited to the above example, and the order of lamination of these layers may be reversed from the above order of lamination.

[0137] The intermediate layer 12D is an adhesive layer 12D １ and the ultraviolet curing resin layer 12D. ２ and an adhesive layer 12D are provided on the color-developing layer 13C in this order. １ The coloring layer 13C and the ultraviolet curing resin layer 12D ２ Adhesive layer 12D １ The ultraviolet curing resin layer 12D may be able to insulate the color-forming layer 13C from the cover layer 14. ２ The adhesive layer 12D can insulate the color-forming layer 13C from the cover layer 14 and can also suppress the diffusion of the constituent materials (e.g., the third color-forming compound) between the color-forming layer 13C and the cover layer 14. １ and the ultraviolet curing resin layer 12D ２ The order of lamination of these layers is not limited to the above example, and the order of lamination of these layers may be reversed from the above order of lamination.

[0138] Adhesive layer 12A １ , adhesive layer 12B １ , adhesive layer 12C １ and adhesive layer 12D １ is, for example, a double-sided adhesive film such as OCA (Optical Clear Adhesive).

[0139] Ultraviolet curing resin layer 12A ２ , ultraviolet curing resin layer 12B ２ , ultraviolet curing resin layer 12C ２ and the ultraviolet curing resin layer 12D ２ The ultraviolet curable resin layer 12A includes a polymerized and solidified ultraviolet curable resin. ２, ultraviolet curing resin layer 12B ２ , ultraviolet curing resin layer 12C ２ and the ultraviolet curing resin layer 12D ２ The ultraviolet-curable resin layer 12A includes a polymer of a polymerizable compound and a polymer that has undergone a structural change due to the generation of active species by a polymerization initiator upon irradiation with external energy (ultraviolet rays). The ultraviolet-curable resin composition includes, for example, at least one selected from the group consisting of radical polymerization type ultraviolet-curable resin compositions and cationic polymerization type ultraviolet-curable resin compositions. The ultraviolet-curable resin composition may optionally include at least one selected from the group consisting of a sensitizer, a filler, a stabilizer, a leveling agent, an antifoaming agent, a viscosity adjuster, and the like. ２ , ultraviolet curing resin layer 12B ２ , ultraviolet curing resin layer 12C ２ and the ultraviolet curing resin layer 12D ２ The ultraviolet curing resin layer 12D is provided as needed and does not have to be provided. ２ may have a function of blocking ultraviolet light caused by thermal curing.

[0140] (Recording Layer 24) The recording layer 24 is provided on the intermediate layer 23, and covers the intermediate layer 23 and the recording layer 10 included in the intermediate layer 23. The recording layer 24 has a peak wavelength λ ４ Laser light L having ４ The laser is configured to be able to draw a monochromatic image (a monochrome image) by laser irradiation. The monochromatic image is visible under visible light and can be captured by an imaging device under infrared light. The color of the drawn portion of the monochromatic image (the portion irradiated with the laser) can be, for example, black or brown, but is not limited to these colors.

[0141] Peak wavelength λ ４ The lower limit of the peak wavelength λ is, for example, 1000 nm or more. ４ The upper limit of the peak wavelength λ is, for example, 11 μm or less. ４ Specifically, the peak wavelength λ is, for example, about 1064 nm. ４ Laser light L having ４ is an example of the second laser light having a second peak wavelength in the claims.

[0142] The recording layer 24 may be in the form of a film. The recording layer 24 may be translucent to visible light in its initial state before recording. The recording layer 24 may become absorbent in the visible light range upon irradiation with laser light, or may be absorbent in the visible light range from the beginning even without irradiation with laser light. The recording layer 24 is preferably a laser marking layer. The laser marking layer may be a known laser marking sheet. Many known laser marking sheets become absorbent in the visible light range upon irradiation with laser light, or are initially absorbent in the visible light range even without irradiation with laser light. The laser marking layer is configured to be laser markable by, for example, at least one of the following methods (1) to (5). However, the laser marking layer may also be configured to be laser markable by a method other than the following methods (1) to (5). (1) A method of foaming a resin material to develop color. (2) A method of adding an additive that absorbs laser light to a resin material, causing the additive itself to develop color. (3) A method of adding an additive that absorbs laser light to a resin material, causing the additive to heat up and carbonize the surrounding resin material, resulting in color development. (4) A method of etching the surface of a resin layer by irradiating it with a laser, utilizing changes in the surface condition. (5) A method of marking by irradiating a black or dark colored resin material with laser light, causing the colorant (carbon black) to sublimate (decompose) and decolorize (exposing the base color of the resin material).

[0143] Specifically, the laser marking layer includes, for example, a light-to-heat conversion agent and a resin material. The light-to-heat conversion agent includes, for example, carbon. The resin material includes, for example, a polycarbonate resin.

[0144] Peak wavelength λ １ , peak wavelength λ ２ , peak wavelength λ ３ and peak wavelength λ ４ is λ ３ <λ ２ <λ １ <λ ４ It is preferable to satisfy the following relationship. This allows the recording layer 10 and the recording layer 24 to be written independently.

[0145] (Image in drawing area R1) An image may be drawn in the drawing area R1 of the recording medium 20. Characters or the like may be drawn in the drawing area R2 of the recording medium 20. The image drawn in the drawing area R1 will be described below with reference to Fig. 4. Note that in Fig. 4, the first image P1 and the visible image P3 are monochromatic images (black and white images), but they may also be multicolor images such as full color.

[0146] The image in the drawing region R1 is formed by overlapping a first image P1 drawn on the recording layer 10 and a second image P2 drawn on the recording layer 24 in the thickness direction of the recording medium 20. In other words, the image in the drawing region R1 is a composite image of the first image P1 and the second image P2.

[0147] The first image P1 is a photograph of a face or the like. The first image P1 is, for example, a monochromatic image or a multicolor image. The multicolor image may be a full-color image. The first image P1 is visible under visible light but cannot be captured under infrared light.

[0148] The second image P2 is an image obtained by extracting a portion of the first image P1 where the contrast changes significantly compared to the surrounding area, more specifically, a contour (part of the first image P1) extracted from the first image P1. The second image P2 may further include an image other than the contour. The second image P2 is, for example, a monochromatic image. The color of the monochromatic image is, for example, black or brown. The second image P2 is visible under visible light and can be captured by an imaging device under infrared light.

[0149] The visible image P3 represents an image of the drawing region R1 viewed under visible light. The visible image P3 is an image (composite image) obtained by superimposing the first image P1 and the second image P2. More specifically, the visible image P3 is, for example, an image of the first image P1 with its outline colored black or brown.

[0150] The infrared image (IR image) P4 represents an image of the drawing area R1 captured by an imaging device under infrared light. The infrared image P4 is an image that is substantially identical to the second image P2. In this specification, substantially identical includes identical.

[0151] [2.2 Method for Manufacturing Recording Medium] Next, an example of a method for manufacturing the recording medium 20 according to the first embodiment of the present disclosure will be described.

[0152] First, the recording layer 10 is prepared by forming the intermediate layer 12A, color-forming layer 13A, intermediate layer 12B, color-forming layer 13B, intermediate layer 12C, color-forming layer 13C, intermediate layer 12D, and cover layer 14 on the substrate 11. However, the order in which these layers are formed on the substrate 11 is not particularly limited, and the order does not have to be intermediate layer 12A, color-forming layer 13A, intermediate layer 12B, color-forming layer 13B, intermediate layer 12C, color-forming layer 13C, intermediate layer 12D, and cover layer 14. Next, the substrate 21 on which the under layer 22 is formed is prepared. Next, the intermediate layer 23 is placed on the under layer 22, and then the recording layer 10 is fitted into the housing portion 23HL of the intermediate layer 23. Note that the intermediate layer 23 with the recording layer 10 already fitted into the housing portion 23HL may be placed on the under layer 22. Next, the recording layer 24 is placed on the intermediate layer 23.

[0153] Next, the laminate obtained as described above is sandwiched between metal plates and heated and pressurized to heat-seal the under layer 22 and the intermediate layer 23, and the intermediate layer 23 and the recording layer 24. The temperature applied to the laminate during heat-sealing is preferably 130°C or higher and 200°C or lower. If the temperature applied to the laminate is 130°C or higher, sufficient fusion strength can be obtained. On the other hand, if the temperature applied to the laminate is 200°C or lower, damage to the recording layer 10 can be reduced. In this manner, the desired recording medium 20 is obtained.

[0154] 5 , an example of the configuration of a drawing system 50 used for drawing on the recording medium 20 will be described. The drawing system 50 includes a control device 51, an imaging device 52, a colorimeter 53, a display unit 54, an operation unit 55, a laser light irradiation device (first irradiation device) 56, and a laser light irradiation device (second irradiation device) 57.

[0155] (Image capture device 52) Based on the control of the control device 51, the image capture device 52 captures an image such as a facial photograph to be drawn on the recording medium 20. The image capture device 52 may include a control unit. In this case, the control unit of the image capture device 52 may execute the image capture operation based on a command from the control device 51.

[0156] (Colorimeter 53) The colorimeter 53 measures the color of the color chart drawn on the sample based on the control of the control device 51. The sample may have the same configuration as the recording medium 20. The colorimeter 53 may include a control unit. In this case, the control unit of the colorimeter 53 may perform the colorimetric operation based on a command from the control device 51.

[0157] (Display Unit 54) The display unit 54 is, for example, a display such as a liquid crystal display or an organic EL (Electro Luminescence) display. These displays may be displays with built-in touch panels. The display unit 54 displays images under the control of the control device 51. For example, the display unit 54 displays an operation menu of the drawing system 50, images captured by the imaging device 52, etc.

[0158] (Operation Unit 55) The operation unit 55 is a user interface such as a keyboard and a pointing device. The operation unit 55 may be a voice input unit. The operation unit 55 may be a touch panel of the display unit 54. The operation unit 55 may be physical buttons. The operation unit 55 is an interface that accepts user operations. The operation unit 55 outputs operation data according to the user operations to the processing unit. The operation unit 55 may be capable of accepting operations on the screen of the display unit 54.

[0159] (Control Device 51) The control device 51 controls the operation of the drawing system 50. Specifically, the control device 51 controls the operation of the imaging device 52, the colorimeter 53, the display unit 54, the operation unit 55, the laser light irradiation device 56, and the laser light irradiation device 57.

[0160] The control device 51 generates a first drawing setting file and a second drawing setting file from the measurement results of the reference color chart measured by the colorimeter 53 and stores them in the storage unit 511 .

[0161] The control device 51 converts the original image stored in the storage unit 511 into a driving voltage value for drawing by the laser light irradiation device 56 based on the first drawing setting file stored in the storage unit 511, and generates drawing data (data of driving voltage values) for the first image P1. The control device 51 controls the laser light irradiation device 56 based on the drawing data for the first image P1, and draws the first image P1 on the recording layer 10.

[0162] The control device 51 processes the original image stored in the storage unit 511 and generates drawing data for the second image P2. More specifically, the control device 51 extracts contour data from the original image stored in the storage unit 511, and then converts the extracted data into driving voltage values ​​for the laser light irradiation device 57 during drawing based on the second drawing setting file stored in the storage unit 511, thereby generating drawing data (data of driving voltage values) for the second image P2. The control device 51 controls the laser light irradiation device 57 based on the drawing data for the second image P2, and draws the second image P2 on the recording layer 24.

[0163] The control device 51 includes, for example, a processing unit 512, a storage unit 511, and an interface unit (hereinafter referred to as "I / F unit") 513. The control device 51 can be configured by, for example, an information processing device such as a personal computer.

[0164] (Storage Unit 511) The storage unit 511 includes, for example, a semiconductor memory, a magnetic storage device, or a combination thereof. The semiconductor memory includes, for example, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable and programmable read-only memory (EEPROM), a solid state drive (SSD), a flash memory, or a combination of two or more of these. The magnetic storage device includes, for example, a hard disk drive (HDD). The storage unit 511 stores an operating program for the drawing system 50.

[0165] The storage unit 511 also stores data on the color chart to be drawn on the sample and the measurement results of the color chart measured by the colorimeter 53. The storage unit 511 stores, as original images, images captured by the imaging device 52. Furthermore, the storage unit 511 may store, as original images, images received from a cloud server or the like via the I / F unit 513.

[0166] The storage unit 511 also stores a first drawing setting file and a second drawing setting file generated by the control device 51. The first drawing setting file is a file for converting the original image into drive voltage values ​​for the laser light irradiation device 56 during drawing and generating drawing data (data on drive voltage values) for the first image P1. The second drawing setting file is a file for converting the extracted data into drive voltage values ​​for the laser light irradiation device 57 during drawing and generating drawing data (data on drive voltage values) for the second image P2. The extracted data is data extracted from the original image stored in the storage unit 511, and in the first embodiment, is data on the contours of the original image stored in the storage unit 511.

[0167] (Processing Unit 512) The processing unit 512 is, for example, a CPU (Central Processing Unit). The processing unit 512 is configured to read a program from the storage unit 511 and execute the read program to perform various control operations. This program may be stored in the storage unit 511 in advance, or may be acquired and stored in the storage unit 511 when needed. The program may be acquired, for example, by being read from various recording media readable by the control device 51, or by being received via a communication line connected to the I / F unit 513.

[0168] (I / F Unit 513) The I / F unit 513 has a communication module and can transmit and receive information to and from the imaging device 52, the colorimeter 53, the display unit 54, the operation unit 55, the laser light irradiation device 56, and the laser light irradiation device 57. The I / F unit 513 can also transmit and receive information to and from a server such as a cloud server via the Internet. The I / F unit 513 includes at least one of a wired interface and a wireless interface.

[0169] (Laser Light Irradiation Device 56) The laser light irradiation device 56 is used for drawing on the recording layer 10 and has a peak wavelength λ １ Laser light L having １ can be irradiated onto the color-producing layer 13A, with a peak wavelength λ ２ Laser light L having ２ can be irradiated onto the color-producing layer 13B, and the peak wavelength λ ３ Laser light L having ３ The laser beam irradiation device 56 is configured to be able to irradiate the color-forming layer 13C with the laser beam. The laser beam irradiation device 56 draws the first image P1 on the recording layer 10 based on data for drawing the recording layer 10 (i.e., data for drawing the first image P1) read from the storage unit 511 under the control of the control device 51. The laser beam irradiation device 56 includes, for example, a semiconductor laser device. The laser beam irradiation device 56 may also be equipped with a control unit. In this case, the control unit of the laser beam irradiation device 56 may execute the drawing operation based on a command from the control device 51.

[0170] (Laser Light Irradiation Device 57) The laser light irradiation device 57 is used to draw the recording layer 24 and emits a laser beam having a wavelength λ ４ Laser light L having ４ The laser beam irradiation device 57 is configured to be able to irradiate the recording layer 24 with a laser beam of, for example, a YAG laser, a YV04 laser, or a CO ２ The laser light irradiation device 57 may include a control unit. In this case, the control unit of the laser light irradiation device 57 may perform the drawing operation based on a command from the control device 51.

[0171] [2.4 Method of Generating First Drawing Setting File] Next, an example of a method of generating the first drawing setting file will be described with reference to FIG.

[0172] First, in step S11, the control device 51 controls the laser light irradiation device 56 to draw a reference color chart on the recording layer 10 of the first sample based on the data for drawing the reference color chart stored in the storage unit 511. The first sample used for drawing in step S11 may have the same configuration as the recording medium 20, or may have a configuration obtained by omitting the recording layer 24 from the recording medium 20. Next, in step S12, the control device 51 controls the colorimeter 53 to measure the color of the reference color chart drawn on the recording layer 10 of the sample in step S11.

[0173] Next, in step S13, the control device 51 generates a first gradation voltage conversion table and an ICC (International Color Consortium) profile based on the colorimetric values ​​measured in step S12. Next, in step S14, the control device 51 generates a first rendering setting file using the first gradation voltage conversion table and ICC profile generated in step S13 and stores the file in the storage unit 511. The first gradation voltage conversion table describes the correspondence between gradation values ​​in the leuco color space and output setting values. This allows for obtaining output setting values ​​suitable for rendering the leuco image data. An ICC profile is a set of data in color management that characterizes color-related input / output devices and color spaces in accordance with standards published by the ICC. Using an ICC profile is preferable for achieving excellent color reproduction, but it may be omitted if necessary.

[0174] [2.5 Method of Generating Second Drawing Setting File] Next, an example of a method of generating a second drawing setting file will be described with reference to FIG.

[0175] First, in step S21, the control device 51 controls the laser light irradiation device 57 to draw a reference color chart on the recording layer 24 of the second sample based on the data for drawing the reference color chart stored in the memory unit 511. The second sample used for drawing in step S21 may have the same configuration as the recording medium 20, or may have a configuration obtained by omitting the recording layer 10 from the recording medium 20. The reference color chart used for drawing in step S21 may be the same as or different from the reference color chart used in the method for generating the first drawing setting file. Next, in step S22, the control device 51 controls the colorimeter 53 to measure the color of the reference color chart drawn on the recording layer 24 of the sample in step S21.

[0176] Next, in step S23, the control device 51 generates a second gradation voltage conversion table based on the colorimetric values ​​measured in step S22. Next, in step S24, the control device 51 generates a second drawing setting file using the second gradation voltage conversion table generated in step S23, and stores it in the storage unit 511. The second gradation voltage conversion table describes the correspondence between gradation values ​​in the grayscale and output setting values.

[0177] [2.6 Drawing Method on Recording Medium] Next, an example of a drawing method on the recording medium 20 will be described with reference to FIG.

[0178] In step S31, the control device 51 controls the imaging device 52 to capture an image such as a face photograph and store it in the storage unit 511 as an original image.

[0179] In step S32, the control device 51 uses the first drawing setting file stored in the memory unit 511 to convert the original image stored in the memory unit 511 into the driving voltage value for drawing of the laser light irradiation device 56, and generates drawing data for the first image P1.

[0180] In step S33, the control device 51 extracts contour data from the original image stored in the memory unit 511, and then uses the second drawing setting file to convert the extracted data into a driving voltage value for the laser light irradiation device 57, thereby generating drawing data for the second image P2.

[0181] In step S34, the control device 51 controls the laser light irradiation device 56 based on the drawing data for the first image P1 generated in step S32 to draw the first image P1 on the recording layer 10. Furthermore, the control device 51 controls the laser light irradiation device 57 based on the drawing data for the second image P2 generated in step S33 to draw the second image P2 on the recording layer 24. At this time, the drawing of the first image P1 and the drawing of the second image P2 are performed so that the outline of the first image P1 included in the second image P2 (a part of the first image P1) overlaps with the first image P1 on the recording layer 10.

[0182] The imaging process for the recording layer 10 and the imaging process for the recording layer 24 may be performed simultaneously or at different times. When the imaging process for the recording layer 10 and the imaging process for the recording layer 24 are performed at different times, the order of these imaging processes is not particularly limited, but it is preferable to perform the imaging process for the recording layer 10 before the imaging process for the recording layer 24. This is for the following reason. When imaging is performed on the recording layer 24, the imaging portion (colored portion) becomes infrared absorbing. Therefore, if the imaging process for the recording layer 24 is performed before the imaging process for the recording layer 10, near-infrared laser light may be absorbed by the imaging portion of the recording layer 24 during imaging of the recording layer 10, which may affect the imaging properties of the recording layer 10. Therefore, by performing the imaging process for the recording layer 10 before the imaging process for the recording layer 24, it is possible to prevent the imaging portion of the recording layer 24 from affecting the imaging properties of the recording layer 10.

[0183] The details of the drawing step of the first image P1 are as follows (step S35). Here, the case where the coloring layer 13A, the coloring layer 13B, and the coloring layer 13C exhibit cyan, magenta, and yellow colors, respectively, will be described as an example. １ , laser light L ２ and laser light L ３ As the scanning method, for example, a raster scanning method can be used, but the scanning method is not limited to this.

[0184] The control device 51 drives the laser light irradiation device 56 based on the drawing data for the first image P1 generated in step S32, and applies a peak wavelength λ １ Laser light (near-infrared laser light) L １ is irradiated onto the color-forming layer 13A. As a result, the photothermal conversion material contained in the irradiated position of the color-forming layer 13A generates heat, causing a color reaction (color-developing reaction) between the color-forming compound and the color developer, and the irradiated position of the color-forming layer 13A develops a cyan color.

[0185] The control device 51 drives the laser light irradiation device 56 based on the drawing data for the first image P1 generated in step S32, and applies a peak wavelength λ ２ Laser light (near-infrared laser light) L ２The color-forming layer 13B is irradiated with the light. This causes a color-forming reaction similar to that of the color-forming layer 13A, and the irradiated position of the color-forming layer 13B develops a magenta color.

[0186] The control device 51 drives the laser light irradiation device 56 based on the drawing data for the first image P1 generated in step S32, and applies a peak wavelength λ ３ Laser light (near-infrared laser light) L ３ The color-forming layer 13C is irradiated with the light. This causes a color reaction similar to that of the color-forming layer 13A, and the irradiated position of the color-forming layer 13C develops a yellow color.

[0187] As described above, the color forming layers 13A, 13B, and 13C develop magenta, cyan, and yellow colors at the irradiated positions, respectively, thereby forming a desired first image P1 on the recording medium 20.

[0188] The laser light irradiation device 56 emits laser light L １ , laser light L ２ and laser light L ３ When the recording layer 24 is irradiated with the laser beam L, the recording layer 24 is not laser marked. １ , laser light L ２ and laser light L ３ This is because it does not contain additives that absorb carbon dioxide.

[0189] Laser light L directed to the color-producing layer 13A １ and the laser light L ２ and the laser light L ３ The irradiation of the laser light L may be performed simultaneously or at different times. １ , laser light L ２ and laser light L ３ When the irradiation of the laser beams L is performed at different times, １ , laser light L ２ and laser light L ３ The order of irradiation is arbitrary.

[0190] The details of the drawing process of the second image P2 are as follows (step S36). The laser light irradiation device 57 drives the laser light irradiation device 57 based on the drawing data of the second image P2, and emits the laser light having a peak wavelength λ ４ Laser light L having ４ The recording layer 24 is irradiated with the laser light L. As a result, an additive (e.g., a photothermal conversion agent) contained in a predetermined position of the recording layer 24 is converted into ４ The laser light L is absorbed, and the predetermined position is laser-marked, and the second image P2 is drawn. ４ As the scanning method, for example, a raster scanning method can be used, but the scanning method is not limited to this.

[0191] The laser light irradiation device 57 emits laser light L ４ When the recording layer 10 is irradiated with the laser light L, the recording layer 10 does not develop color. ４ This is because it does not contain additives that absorb carbon dioxide.

[0192] [2.7 Effects] As described above, in the recording medium 20 according to the first embodiment, the recording layer (first recording layer) 10 has a peak wavelength λ １ , peak wavelength λ ２ , peak wavelength λ ３ Laser light L １ , laser light L ２ , laser light L ３ On the other hand, the recording layer (second recording layer) 24 has a peak wavelength λ ４ Laser light L having ４ The peak wavelength λ １ , peak wavelength λ ２ , peak wavelength λ ３ , peak wavelength λ ４ are set to different values. As a result, since the drawing conditions of the laser light for the recording layer 10 and the recording layer 24 are different, when drawing on the recording layer 10, it is possible to prevent the recording layer 24 located above the recording layer 10 from being drawn unintentionally, making it difficult to draw on the recording layer 10. Therefore, it is possible to draw on the recording layer 10 as intended.

[0193] In the recording medium 20 according to the first embodiment, an image may be drawn in the drawing region R1 of the recording medium 20. The image in the drawing region R1 is formed by overlapping a first image P1 drawn on the recording layer 10 and a second image P2 drawn on the recording layer 24 in the thickness direction of the recording medium 20. The first image P1 is visible under visible light but cannot be captured by an imaging device under infrared light. The second image P2 is visible under visible light and can be captured by an imaging device under infrared light. The second image P2 is an image of a portion of the first image P1, i.e., a contour image of the first image P1 in the first embodiment. Therefore, the authenticity of the recording medium 20 can be determined by comparing a visible image P3 of the drawing region R1 viewed under visible light with an infrared image P4 of the drawing region R1 captured under infrared light and determining whether the contour of the infrared image P4 matches the contour of the visible image P3. This improves the security of the recording medium 20.

[0194] 4, the second image P2 is a partial image of the first image P1, specifically, a contour image of the first image P1, and therefore, even when the second image P2 is drawn so as to overlap the first image P1, it is possible to prevent the first image P1, which is a multi-color image, from being obscured by the second image P2, which is a monochrome image of black, brown, or the like. Therefore, it is possible to prevent a decrease in the display quality of the recording medium 20.

[0195] 9 is a cross-sectional view of a recording medium 20A according to a second embodiment of the present disclosure. The recording medium 20A differs from the recording medium 20 according to the first embodiment in that it includes a recording layer 24, an intermediate layer 23, and a resin layer 25, which are provided in this order on a substrate 21.

[0196] The resin layer 25 is translucent to visible light. The resin layer 25 is, for example, a film. Examples of materials for the resin layer 25 include the same materials as those for the base material 21.

[0197] The second image P2 may be drawn in the drawing area R1 of the recording medium 20. The second image P2 may be a monochrome image obtained by performing grayscale conversion on the first image P1, or the second image P2 may be a partial image of the first image P1, for example, a contour image of the first image P1. However, from the viewpoint of suppressing a decrease in the display quality of the recording medium 20, it is preferable that the second image P2 be a partial image of the first image P1.

[0198] Here, the reason why it is preferable that the second image P2 is a partial image of the first image P1 will be described, taking as an example a case where the second image P2 is a contour image of the first image P1.

[0199] 10, both the first image P1 and the second image P2 are monochrome images, but in reality, the first image P1 is a multicolor image such as a full-color image, and the second image P2 is a monochrome image such as black or brown. The spacing between the diagonal lines in the first image P1 and the visible image P3 represents the brightness of the images, with the wider the spacing between the diagonal lines, the brighter the images.

[0200] If the second image P2 is a monochrome image obtained by, for example, converting the first image P1 into a grayscale image, the second image P2, which is a monochrome image such as black or brown, may appear behind the first image P1, which is a multicolor image such as a full-color image. In this case, as shown in Fig. 10, the visible image P3 in the drawing region R1 will be darker than the first image P1 drawn on the recording layer 10, and there is a risk that the display quality of the recording medium 20 will be reduced.

[0201] On the other hand, if the second image P2 is a contour image of the first image P1, as shown in Fig. 4, the contour of the visible image P3 in the drawing area R1 may appear emphasized due to the overlap of the first image P1 and the second image P2, but this can prevent the visible image P3 in the drawing area R1 from becoming darker than the first image P1 drawn on the recording layer 10. Therefore, it is possible to prevent a decrease in the display quality of the recording medium 20.

[0202] [3.2 Effects] In the recording medium 20A according to the second embodiment, the recording layer 24 and the recording layer 10 located above the recording layer 24 are subjected to different imaging conditions using laser light. This makes it possible to prevent unintended imaging of the recording layer 10 located above the recording layer 24 when imaging the recording layer 24. Therefore, it is possible to perform intended imaging on the recording layer 24.

[0203] 11A, in the recording medium 20A according to the second embodiment, even when the drawing region 10R is set so as to extend beyond the periphery of the recording layer 10 in a plan view, it is possible to suppress color development in the recording layer 24 due to irradiation with a laser beam for drawing on the recording layer 10. Therefore, as shown in FIG. 11B, an image such as a photograph can be drawn only on the recording layer 10. Furthermore, drawing can be performed on a production line or the like without having to worry about the boundary between the recording layer 10 and the recording layer 24 in the in-plane direction of the recording medium 20A, thereby improving throughput and yield.

[0204] On the other hand, as shown in FIG. 12 , in a recording medium 120A that includes a general full-color laser drawing sheet 110 instead of the recording layer 10, the drawing conditions for the full-color laser drawing sheet 110 and the recording layer 24 located below the full-color laser drawing sheet 110 are substantially the same. Therefore, if the drawing region 10R is set to extend beyond the periphery of the full-color laser drawing sheet 110 in a planar view, the recording layer 24 will develop color when irradiated with the drawing laser light from the full-color laser drawing sheet 110. Therefore, as shown in FIG. 12 , an image such as a photograph will be drawn beyond the full-color laser drawing sheet 110. Furthermore, the image in the portion that extends beyond the full-color laser drawing sheet 110 will be drawn in a color (e.g., black or brown) different from that of the full-color laser drawing sheet 110.

[0205] <4 Modifications> [Modification 1] In the first and second embodiments, an example has been described in which the second image P2 of the recording layer 24 includes the outline of the first image P1 of the recording layer 10 (see FIG. 4). However, the present disclosure is not limited to this example, and for example, as shown in FIG. 13, the second image P2 of the recording layer 24 may include the black portion of the first image P1 of the recording layer 10. Note that FIG. 13 shows an example in which the first image P1 is a facial photograph, and the second image P2 includes the hair and pupils of the facial photograph in the first image P1.

[0206] When the second image P2 of the recording layer 24 includes the black portion of the first image P1 of the recording layer 10, an image that is substantially the same as the first image P1 is visually recognized as the visible image P3, as shown in Fig. 13. As the infrared image P4, an image that is substantially the same as the second image P2 is captured by the imaging device, as shown in Fig. 13.

[0207] The control device 51 of the drawing system 50 generates the second image P2 as follows. That is, the control device 51 extracts black portions from the first image P1 and generates the second image P2. More specifically, the control device 51 extracts data corresponding to the black portions of the first image P1 from the drawing data of the first image P1, and then converts the extracted data into a drive voltage value for the laser light irradiation device 57 during drawing, thereby generating the drawing data of the second image P2.

[0208] The data corresponding to the black portion of the first image P1 is, for example, a specified voltage value V ｔｈ The maximum voltage value of the drawing data for the first image P1 is V ｍａｘ In this case, the specified voltage value V ｔｈ For example, V ｍａｘ ×0.8 or V ｍａｘ ×0.9.

[0209] [Modification 2] As shown in FIG. 14, the second image P2 on the recording layer 24 may include both the contour P21 of the first image P1 on the recording layer 10 and the black portion P22 of the first image P1 on the recording layer 10.

[0210] When the second image P2 on the recording layer 24 includes both the contour P21 of the first image P1 on the recording layer 10 and the black portion P22 of the first image P1 on the recording layer 10, an image in which the contour of the first image P1 is colored black, brown, or the like is visually recognized as the visible image P3, as shown in Fig. 14. As the infrared image P4, an image substantially identical to the second image P2 is captured by the imaging device, as shown in Fig. 14.

[0211] The control device 51 of the drawing system 50 generates the second image P2 as follows. That is, the control device 51 extracts both the contour P21 of the first image P1 of the recording layer 10 and the black portion P22 from the first image P1, and combines the contour P21 with the black portion P22 to generate the second image P2. Details of the process of extracting the contour of the first image P1 by the control device 51 are as described in the first embodiment. Details of the process of extracting the black portion of the first image P1 by the control device 51 are as described in Modification 1.

[0212] [Variation 3] In Variation 2, an example was described in which the second image P2 of the recording layer 24 includes the contour P21 of the first image P1 of the recording layer 10 and the black portion P22 of the first image P1 of the recording layer 10 (see FIG. 14 ). However, the present disclosure is not limited to this example. For example, the second image P2 of the recording layer 24 may include a color portion of the first image P1 of the recording layer 10 that has a predetermined color density or higher, instead of the black portion P22 of the first image P1 of the recording layer 10. The color portion that has a predetermined color density or higher may be a substantially maximum color density portion. Alternatively, the color portion that has a predetermined color density or higher may be a color density portion that has a color density of 1.0 or higher. This is because a color density of 1.0 or higher results in a very clear image.

[0213] The control device 51 of the drawing system 50 generates the second image P2 as follows. That is, the control device 51 extracts color-developing portions of the first image P1 that have a predetermined color density or higher, and generates the second image P2. More specifically, the control device 51 extracts data corresponding to the color-developing portions of the first image P1 that have a predetermined color density or higher from the drawing data of the first image P1, and then converts the extracted data into a drive voltage value for the laser light irradiation device 57 during drawing, and generates the drawing data of the second image P2.

[0214] [Variation 4] As shown in Fig. 15, the second image P2 of the recording layer 24 may include a key plate portion (K portion) of the first image P1 of the recording layer 10. In Fig. 15, both the first image P1 and the second image P2 are monochrome images, but in reality, the first image P1 is a multicolor image such as a full-color image, and the second image P2 is a monochrome image such as black or brown. The spacing between the diagonal lines in the first image P1 and the visible image P3 represents the brightness of the images, with the wider the spacing between the diagonal lines, the brighter the images.

[0215] When the second image P2 of the recording layer 24 includes the key plate portion of the first image P1 of the recording layer 10, the visible image P3 may be an image that is slightly darker than the first image P1, as shown in Fig. 15. As the infrared image P4, an image that is substantially the same as the second image P2 is captured by the imaging device, as shown in Fig. 15.

[0216] The control device 51 of the drawing system 50 generates the second image P2 as follows. That is, the control device 51 extracts the key plate portion of the first image P1 of the recording layer 10 and generates the second image P2. More specifically, the control device 51 extracts data corresponding to the key plate portion of the first image P1 from the drawing data of the first image P1, and then converts the extracted data into a drive voltage value for drawing the laser light irradiation device 57, and generates drawing data (data of the drive voltage value) for the second image P2.

[0217] The control device 51 may correct the first image P1 to be brighter, and then draw the corrected first image P1 on the recording layer 10. In this case, by combining the first image P1 and the second image P2, it is possible to prevent the visible image P3 from becoming an image darker than the first image P1.

[0218] As a method of correcting the brightness of the first image P1, for example, ＊ The brightness of the first image P1 before correction and the visible image P3 (a composite image of the first image P1 and the second image P2 after correction), for example, the brightness L ＊It is preferable to correct the first image P1 so that the values ​​of the first image P1 and the second image P2 are substantially the same.

[0219] 16 , the second image P2 of the recording layer 24 may include the background portion 17 of the first image P1 of the recording layer 10. The second image P2 of the recording layer 24 may further include at least one of the outline of the first image P1 of the recording layer 10 and the black portion of the first image P1 of the recording layer 10. When the second image P2 of the recording layer 24 includes the background portion 17 of the first image P1 of the recording layer 10, the density of the background portion 17 of the second image P2 may be different from the density of the background portion 17 of the first image P1. For example, the density of the background portion 17 of the second image P2 may be higher than the density of the background portion 17 of the first image P1.

[0220] When the second image P2 of the recording layer 24 includes the background portion 17 of the first image P1 of the recording layer 10, the visible image P3 is an image in which the background portion 17 is darker than that of the first image P1, as shown in Fig. 16. As the infrared image P4, an image that is substantially the same as the second image P2 is captured by the imaging device, as shown in Fig. 16.

[0221] The control device 51 of the drawing system 50 generates the second image P2 as follows. That is, the control device 51 extracts the background portion 17 of the first image P1 and generates the second image P2. More specifically, the control device 51 extracts data corresponding to the background portion of the first image P1 from the drawing data of the first image P1, and then converts the extracted data into a drive voltage value for the laser light irradiation device 57 during drawing, thereby generating the drawing data of the second image P2.

[0222] The control device 51 may extract the background portion of the first image P1 and at least one of the contours and black portions of the first image P1, and generate the second image P2. More specifically, the control device 51 may extract data corresponding to the background portion of the first image P1 and data corresponding to at least one of the contours and black portions of the first image P1 from the drawing data of the first image P1, and then convert the extracted data into a drive voltage value for the laser light irradiation device 57 during drawing, and generate the drawing data of the second image P2.

[0223] 17 , the second image P2 of the recording layer 24 may include the outline of the first image P1 of the recording layer 10 and identification information 15. The identification information 15 is added to a portion of the second image P2 that corresponds to the black portion of the first image P1. The identification information 15 is information used to determine the authenticity of the recording medium 20, and may be a design or the like.

[0224] When the recording layer 10 is provided above the recording layer 24 and the second image P2 of the recording layer 24 includes the outline of the first image P1 of the recording layer 10 and the identification information 15, in the visible image P3, as shown in Fig. 17, the identification information 15 is hidden by the black portions of the first image P1 and cannot be seen. In the infrared image P4, as shown in Fig. 17, the identification information 15 is not hidden by the black portions of the first image P1 and can therefore be confirmed. Therefore, the authenticity of the recording medium 20 can be determined by confirming the identification information 15, which is hidden by the black portions in the visible image P3, in the infrared image P4.

[0225] The control device 51 of the drawing system 50 generates the second image P2 as follows: The control device 51 extracts both the contours of the first image P1 and the black portions from the first image P1. The control device 51 replaces the extracted black portions with identification information 15 such as a design, and then combines the extracted contours of the first image P1 with the replaced identification information 15 such as a design to generate the second image P2.

[0226] 18 , the first image P1 of the recording layer 10 may include identification information 16. The identification information 16 is information for determining the authenticity of the recording medium 20, and may be, for example, a mark, a design, or a combination thereof. The position of the identification information 16 in the first image P1 may be, for example, a background portion, but is not limited to this.

[0227] When the first image P1 of the recording layer 10 includes the identification information 16, the identification information 16 can be seen in the visible image P3, as shown in Fig. 18. The identification information 16 cannot be seen in the infrared image P4, as shown in Fig. 18. Therefore, the authenticity of the recording medium 20 can be determined by checking the presence or absence of the identification information 16 in the infrared image P4.

[0228] The control device 51 of the drawing system 50 generates the drawing data for the first image P1 as follows: After adding the identification information 16 to the original image stored in the storage unit 511, the control device 51 uses the first drawing setting file stored in the storage unit 511 to convert the original image with the added identification information 16 into a driving voltage value for the laser light irradiation device 56 during drawing, thereby generating the drawing data for the first image P1.

[0229] [Variation 8] In the first and second embodiments, an example has been described in which the size of the recording layer 10 in a planar view is smaller than the size of the recording layer 24 in a planar view (see FIGS. 2 and 9). However, the sizes of the recording layer 10 and the recording layer 24 are not limited to this example.

[0230] 19, the size of the recording layer 10 in a planar view may be approximately the same as the size of the recording layer 24 in a planar view. In this case, the sizes of the recording layer 10 and the recording layer 24 in a planar view may be approximately the same as the sizes of the substrate 21 and the under layer 22 in a planar view.

[0231] 20 , the size of the recording layer 10 in a planar view may be larger than the size of the recording layer 24 in a planar view. In this case, the recording layer 24 may be accommodated in the accommodation portion 23HL of the intermediate layer 23, and the recording layer 10 may be provided between the substrate 21 and the intermediate layer 23.

[0232] [Modification 9] In the second embodiment, an example has been described in which the recording medium 20A includes an intermediate layer 23 including the recording layer 10 on the recording layer 24 (see FIG. 9). However, the layer configuration of the recording medium 20A is not limited to this example. For example, as shown in FIG. 21, the recording medium 20A may further include a wavelength selection layer 26 between the intermediate layer 23 including the recording layer 10 and the recording layer 24. The wavelength selection layer 26 is configured to reflect visible light but transmit near-infrared (NIR). The wavelength selection layer 26 may be, for example, a dielectric multilayer film, but is not limited thereto.

[0233] [Variation 10] In the first and second embodiments, an example has been described in which the recording layer 10 has three layers, namely, color-forming layer 13A, color-forming layer 13B, and color-forming layer 13C (see FIG. 3 ). However, the layer configuration of the recording layer 10 is not limited to this, and the recording layer 10 may have one, two, or three or more color-forming layers. When the recording layer 10 has one color-forming layer, the color-forming layer may be any one of color-forming layer 13A, color-forming layer 13B, and color-forming layer 13C, or may be a color-forming layer that can exhibit a color different from these layers in a colored state, for example, a color-forming layer that can exhibit black in a colored state.

[0234] [Modification 11] In the first embodiment, an example has been described in which the recording medium 20 includes the substrate 21 and the under layer 22 (see FIG. 2). However, the recording medium 20 is not limited to this example, and the recording medium 20 does not necessarily need to include at least one of the substrate 21 and the under layer 22.

[0235] [Modification 12] In the second embodiment, an example has been described in which the recording medium 20A includes the base material 21 and the resin layer 25 (see FIG. 9). However, the recording medium 20A is not limited to this example, and the recording medium 20A does not necessarily need to include at least one of the base material 21 and the resin layer 25.

[0236] [Modification 13] In the first embodiment, an example has been described in which the intermediate layer 12A, the color-forming layer 13A, the intermediate layer 12B, the color-forming layer 13B, the intermediate layer 12C, the color-forming layer 13C, the intermediate layer 12D, and the cover layer 14 are formed on the substrate 11. However, the method for producing the recording layer 10 is not limited to this, and the recording layer 10 may be produced, for example, as follows.

[0237] The recording layer 10 may be prepared by using the cover layer 14 as a substrate and forming the intermediate layer 12D, the color-forming layer 13C, the intermediate layer 12C, the color-forming layer 13B, the intermediate layer 12B, and the color-forming layer 13A on the cover layer 14. However, the order in which these layers are formed on the cover layer 14 is not particularly limited, and the order does not have to be intermediate layer 12D, the color-forming layer 13C, the intermediate layer 12C, the color-forming layer 13B, the intermediate layer 12B, and the color-forming layer 13A. When preparing the recording layer 10 in the above manner, the substrate 11 and the intermediate layer 12A may or may not be formed on the color-forming layer 13A. If the substrate 11 and the intermediate layer 12A are not formed on the color-forming layer 13A, the recording layer 10 can be made thinner. On the other hand, if the substrate 11 and the intermediate layer 12A are formed on the color-forming layer 13A, the substrate 11 functions as a protective layer, thereby improving the durability of the recording layer 10.

[0238] The recording layer 10 may be produced by using the color-forming layer 13A as a substrate and forming, on the color-forming layer 13A, an intermediate layer 12B, a color-forming layer 13B, an intermediate layer 12C, a color-forming layer 13C, an intermediate layer 12D, and a cover layer 14. However, the order in which these layers are formed on the color-forming layer 13A is not particularly limited, and the order does not have to be intermediate layer 12B, a color-forming layer 13B, an intermediate layer 12C, a color-forming layer 13C, an intermediate layer 12D, and a cover layer 14. When producing the recording layer 10 in the above manner, the substrate 11 and the intermediate layer 12A may or may not be formed below the color-forming layer 13A.

[0239] [Modification 14] In the first embodiment, an example has been described in which the intermediate layers 12A, 12B, 12C, and 12D each include an adhesive layer and an ultraviolet-curable resin layer. However, the configurations of the intermediate layers 12A, 12B, 12C, and 12D are not limited to this, and may be, for example, the configurations described below.

[0240] 22 is a cross-sectional view of a first modified example of the intermediate layer 12A, the intermediate layer 12B, the intermediate layer 12C, and the intermediate layer 12D. ２ and the color-developing layer 13A. ３ The intermediate layer 12B may include an ultraviolet curable resin layer 12B. ２ and the color-developing layer 13B. ３ The intermediate layer 12C may include an ultraviolet curable resin layer 12C. ２ and the color-developing layer 13C. ３ The intermediate layer 12D may include an ultraviolet curable resin layer 12D. ２ and the coloring layer 13D. ３ In FIG. 22, the recording layer 10 may include an adhesive layer 12A. ３ , adhesive layer 12B ３ , adhesive layer 12C ３ and adhesive layer 12D ３ 1, the recording layer 10 is provided with an adhesive layer 12A. ３ , adhesive layer 12B ３ , adhesive layer 12C ３ and adhesive layer 12D ３ It may comprise at least one layer of:

[0241] [Variation 15] Figure 23 is a cross-sectional view of a second variation of intermediate layers 12A, 12B, 12C, and 12D. Intermediate layers 22A, 22B, 22C, and 22D may each be formed of an adhesive layer. The adhesive layer may be a thermal adhesive layer. The thermal adhesive layer contains a thermal adhesive resin that softens or melts at a predetermined temperature to bond the layers together. The other components contained in the thermal adhesive layer are not particularly limited. The thermal adhesive resin may be a thermoplastic resin that softens when heated to its softening or melting point. The thermoplastic resin is not particularly limited, but may include at least one selected from the group consisting of polyamide resin, polyester resin, polyethylene resin, ethylene-vinyl acetate copolymer (EVA), polyurethane resin, and acrylic resin. The predetermined temperature varies depending on the type of thermoplastic resin used in the thermal adhesive resin.

[0242] 23 shows an example in which all of intermediate layer 12A, intermediate layer 12B, intermediate layer 12C, and intermediate layer 12D are formed of adhesive layers, but at least one of intermediate layer 12A, intermediate layer 12B, intermediate layer 12C, and intermediate layer 12D may be formed of an adhesive layer. When intermediate layer 12A, intermediate layer 12B, intermediate layer 12C, and intermediate layer 12D are all formed of thermal adhesive layers, the layers of recording layer 10 can be bonded together with the thermal adhesive layers.

[0243] [Variation 16] In the first embodiment, the imaging device 52 and the colorimeter 53 are not essential components of the drawing system 50, and at least one of the imaging device 52 and the colorimeter 53 does not have to be provided in the drawing system 50.

[0244] If the imaging device 52 is not provided in the drawing system 50, the control device 51 may acquire an image (e.g., a picture or a photograph) used for drawing on the recording medium 20 from outside the drawing system 50 via the I / F unit 513 in a wired or wireless manner. Specifically, for example, the control device 51 may acquire the image used for drawing on the recording medium 20 from a cloud server or the like, or from an external memory or the like. The control device 51 may store the acquired image in the storage unit 511.

[0245] If the drawing system 50 does not include the colorimeter 53, the first drawing setting file and the second drawing setting file may be generated outside the drawing system 50. In this case, the control device 51 may obtain the first drawing setting file and the second drawing setting file from outside the drawing system 50 via the I / F unit 513 in a wired or wireless manner.

[0246] [Variation 17] In the first embodiment, the drawing system 50 may further include an external storage unit. In this case, the external storage unit may store data of a color chart to be drawn on the sample and measurement results of the color chart measured by the colorimeter 53. The external storage unit may also store an image captured by the imaging device 52, and the first drawing setting file and the second drawing setting file generated by the control device 51.

[0247] (Other Modifications) Although the embodiments and modifications of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments and modifications, and various modifications based on the technical ideas of the present disclosure are possible.

[0248] For example, the configurations, methods, steps, shapes, materials, and numerical values, etc., described in the above embodiments and variations are merely examples, and different configurations, methods, steps, shapes, materials, and numerical values, etc., may be used as necessary.

[0249] The configurations, methods, steps, shapes, materials, numerical values, etc. of the above-described embodiments and modified examples can be combined with each other without departing from the spirit of the present disclosure.

[0250] In the above embodiments and modified examples, in the numerical ranges described in stages, the upper limit or lower limit of a numerical range in one stage may be replaced with the upper limit or lower limit of a numerical range in another stage.

[0251] Unless otherwise specified, the materials exemplified in the above-described embodiments and modifications can be used singly or in combination of two or more.

[0252] The present disclosure may also employ the following configurations: (1) A recording medium comprising: a first recording layer configured to be able to draw an image with a first laser beam having a first peak wavelength; and a second recording layer configured to be able to draw an image with a second laser beam having a second peak wavelength different from the first peak wavelength, wherein the first recording layer is configured to be able to develop color with the first laser beam and has a first color-developing layer containing a first leuco dye, the first recording layer and the second recording layer have different recording methods, and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium. (2) The recording medium described in (1), wherein the second recording layer is configured to be able to draw an image that is visible under visible light and can be captured under infrared light. (3) The recording medium according to (1) or (2), wherein a first image visible under visible light is drawn on the first recording layer, and a second image visible under visible light and imageable under infrared light is drawn on the second recording layer, the second image including a portion of the first image, and the portion of the first image included in the second image overlaps with the first image on the first recording layer. (4) The recording medium according to (3), wherein the portion of the first image includes a contour of the first image. (5) The recording medium according to (3), wherein the portion of the first image includes a color portion of the first image that has a specified color density or higher. (6) The recording medium according to (3), wherein the portion of the first image includes a portion of the first image that has approximately the maximum color density. (7) The recording medium according to (3), wherein the portion of the first image includes a black portion of the first image. (8) The recording medium according to (3), wherein the part of the first image includes a contour of the first image and a black part of the first image or a key plate part of the first image. (9) The recording medium according to (3), wherein the first recording layer is provided above the second recording layer, and at least a part of the second image is concealed by the first image on the first recording layer under visible light.(10) The recording medium according to (1), wherein a first image visible under visible light is drawn on the first recording layer, and a second image visible under visible light and imageable under infrared light is drawn on the second recording layer, and a composite image is formed by the first image and the second image. (11) The recording medium according to (10), wherein the second image includes at least one of a black portion of the composite image and a background portion of the composite image. (12) The recording medium according to any one of (1) to (11), wherein the first color-forming layer further includes a matrix resin, a color developer, and a photothermal conversion agent. (13) The recording medium according to any one of (1) to (12), wherein the first recording layer is configured to be able to be imaged also by a third laser beam having a third peak wavelength and a fourth laser beam having a fourth peak wavelength, and the first recording layer further comprises: a second color-producing layer configured to be able to develop color by irradiation with the third laser beam and containing a second leuco dye; and a third color-producing layer configured to be able to develop color by irradiation with the fourth laser beam and containing a third leuco dye, and the first peak wavelength, the second peak wavelength, the third peak wavelength, and the fourth peak wavelength are different from one another. (14) A drawing method comprising: irradiating a first recording layer of a recording medium with a first laser beam having a first peak wavelength to draw a first image; and irradiating a second recording layer of the recording medium with a second laser beam having a second peak wavelength different from the first peak wavelength to draw a second image, wherein the first recording layer is configured to be able to develop color with the first laser beam and has a first color-developing layer containing a first leuco dye, the first recording layer and the second recording layer have different recording methods, and at least a portion of the first recording layer and the second recording layer overlap in a thickness direction of the recording medium. (15) The drawing method described in (14), wherein the second image includes a portion of the first image, and the drawing of the first image and the drawing of the second image are performed such that a portion of the first image included in the second image overlaps the first image. (16) The drawing method described in (14) or (15), further comprising extracting second image information for drawing the second image from first image information for drawing the first image.(17) The drawing method according to any one of (14) to (16), further comprising correcting first image information for drawing the first image so that the first image becomes brighter. (18) A drawing system comprising: a first irradiation device capable of irradiating a first laser beam having a first peak wavelength; a second irradiation device capable of irradiating a second laser beam having a second peak wavelength different from the first peak wavelength; and a control device capable of controlling the first irradiation device and the second irradiation device, wherein the control device performs the following: irradiating a first recording layer of a recording medium with the first laser beam to cause a first leuco dye contained in a first color-developing layer of the first recording layer to develop color, thereby drawing a first image; and irradiating a second recording layer of the recording medium with the second laser beam to draw a second image. (19) The drawing system according to (18), wherein the control device further performs the following: extracting second image information for drawing the second image from the first image information for drawing the first image. (20) The drawing system according to (18) or (19), wherein the control device further corrects first image information for drawing the first image so that the first image becomes brighter. (21) A control device capable of controlling a first irradiation device capable of irradiating a first laser beam having a first peak wavelength and a second irradiation device capable of irradiating a second laser beam having a second peak wavelength different from the first peak wavelength, the control device irradiating a first recording layer of a recording medium with the first laser beam to color a first leuco dye contained in a first color-developing layer of the first recording layer, thereby drawing a first image, and irradiating a second recording layer of the recording medium with the second laser beam to draw a second image.

[0253] 10 Recording layer (first recording layer) 11 Substrate 12A, 12B, 12C, 12D Intermediate layer 12A １ , 12B １ , 12C １ , 12D １ Adhesive layer 12A ２ , 12B ２ , 12C ２ , 12D ２UV-curable resin layer 13A, 13B, 13C Color-developing layer 14 Cover layer 15, 16 Identification information 17 Background portion 20 Recording medium 21 Base material 22 Underlayer 23 Intermediate layer 23HL Storage section 24 Recording layer (second recording layer) 25 Resin layer 50 Drawing system 51 Control device 52 Imaging device 53 Colorimeter 54 Display section 55 Operation section 56 Laser light irradiation device 57 Laser light irradiation device 511 Storage section 512 Processing section 513 Network I / F R1, R2 Drawing area P1 First image P2 Second image P3 Visible image P4 Infrared image

Claims

1. A recording medium comprising: a first recording layer configured to be able to be drawn by a first laser beam having a first peak wavelength; and a second recording layer configured to be able to be drawn by a second laser beam having a second peak wavelength different from the first peak wavelength, wherein the first recording layer is configured to be able to develop color by the first laser beam and has a first color-developing layer containing a first leuco dye, the first recording layer and the second recording layer have different recording methods, and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium.

2. The recording medium according to claim 1, wherein the second recording layer is configured to be capable of drawing an image that is visible under visible light and can be captured under infrared light.

3. The recording medium of claim 1, wherein a first image visible under visible light is drawn on the first recording layer, and a second image visible under visible light and imageable under infrared light is drawn on the second recording layer, the second image includes a portion of the first image, and the portion of the first image included in the second image overlaps with the first image on the first recording layer.

4. The recording medium according to claim 3, wherein the portion of the first image includes a contour of the first image.

5. The recording medium according to claim 3, wherein the portion of the first image includes a coloring portion of the first image having a specified coloring density or higher.

6. The recording medium according to claim 3, wherein the part of the first image includes a substantially maximum color density portion of the first image.

7. The recording medium according to claim 3, wherein the portion of the first image includes a black portion of the first image.

8. The recording medium according to claim 3, wherein the portion of the first image includes a contour of the first image and a black portion of the first image or a key plate portion of the first image.

9. The recording medium according to claim 3, wherein the first recording layer is provided above the second recording layer, and at least a portion of the second image is concealed by the first image in the first recording layer under visible light.

10. The recording medium according to claim 1, wherein a first image viewable under visible light is drawn on the first recording layer, a second image viewable under visible light and imageable under infrared light is drawn on the second recording layer, and a composite image is formed by the first image and the second image.

11. The recording medium according to claim 10, wherein the second image includes at least one of a black portion of the composite image and a background portion of the composite image.

12. The recording medium according to claim 1, wherein the first color-forming layer further comprises a matrix resin, a color developer, and a light-to-heat conversion agent.

13. The recording medium described in claim 1, wherein the first recording layer is configured to be capable of being drawn by a third laser light having a third peak wavelength and a fourth laser light having a fourth peak wavelength, and the first recording layer further has: a second color-producing layer configured to be capable of being colored by irradiation with the third laser light and containing a second leuco dye; and a third color-producing layer configured to be capable of being colored by irradiation with the fourth laser light and containing a third leuco dye, and the first peak wavelength, the second peak wavelength, the third peak wavelength, and the fourth peak wavelength are different from one another.

14. A drawing method comprising: irradiating a first recording layer of a recording medium with a first laser light having a first peak wavelength to draw a first image; and irradiating a second recording layer of the recording medium with a second laser light having a second peak wavelength different from the first peak wavelength to draw a second image, wherein the first recording layer is configured to be colored by the first laser light and has a first color-developing layer containing a first leuco dye, the first recording layer and the second recording layer have different recording methods, and at least a portion of the first recording layer and the second recording layer overlap in the thickness direction of the recording medium.

15. The drawing method according to claim 14, wherein the second image includes a portion of the first image, and the first image and the second image are drawn such that the portion of the first image included in the second image overlaps with the first image.

16. The drawing method according to claim 14, further comprising extracting second image information for drawing the second image from first image information for drawing the first image.

17. The drawing method according to claim 14, further comprising correcting first image information for drawing the first image so that the first image is brighter.

18. A drawing system comprising: a first irradiation device capable of irradiating a first laser light having a first peak wavelength; a second irradiation device capable of irradiating a second laser light having a second peak wavelength different from the first peak wavelength; and a control device capable of controlling the first irradiation device and the second irradiation device, wherein the control device performs the following operations: irradiating a first recording layer of a recording medium with the first laser light, causing a first leuco dye contained in a first color-developing layer of the first recording layer to develop color, thereby drawing a first image; and irradiating a second recording layer of the recording medium with the second laser light, thereby drawing a second image.

19. The drawing system according to claim 18, wherein the control device further executes extracting second image information for drawing the second image from first image information for drawing the first image.

20. The drawing system according to claim 18, wherein the control device further corrects first image information for drawing the first image so that the first image becomes brighter.