Drawings and methods for forming such drawing

Abstract

A drawn object according to one aspect of the present disclosure comprises a layered body in which a plurality of thermosensitive recording layers are laminated through heat insulation layers, the thermosensitive recording layers having different colors and light absorption wavelength bands in a color developing state. In the plurality of thermosensitive recording layers, striped patterns, which have irregular widths and extend in a first direction, are drawn as a drawing mark that is caused by irradiating, with laser light, the surface of an object to be drawn.

Description

[Technical Field]

[0001] This disclosure relates to drawings and methods for forming drawings. [Background technology]

[0002] As an alternative display medium to printed materials, recording media that reversibly record and erase information using heat, so-called reversible thermal recording media, have been developed. In a reversible thermal recording media, for example, multiple reversible thermal recording layers with different photothermal conversion wavelengths are stacked with an insulating layer in between. By pulsed laser light of a predetermined wavelength onto the reversible thermal recording media, heat is selectively generated in a specific reversible thermal recording layer, and information is recorded or erased by the action of the generated heat, causing color development or decolorization (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2003-127446 [Overview of the project]

[0004] Incidentally, Patent Document 1 states that in order to draw on a reversible thermal recording medium with higher resolution, it is necessary to reduce the irradiation area per pixel and irradiate with laser light at a higher energy density. On the other hand, semiconductor lasers have power limitations. Therefore, a problem may arise in which the desired image quality cannot be obtained due to insufficient laser power. Accordingly, it is desirable to provide a method for forming a drawn object that can achieve high image quality with low power, and a drawn object formed by such a method.

[0005] A drawing relating to the first aspect of this disclosure comprises a recording medium in which a plurality of thermal recording layers having different colors and light absorption wavelength bands in their colored state are stacked with respect to an insulating layer. The plurality of thermal recording layers have irregular stripe patterns extending in a first direction as drawing marks caused by continuous irradiation of the recording medium surface with laser light in the scanning direction.

[0006] In the drawing according to the first aspect of this disclosure, multiple thermal recording layers are drawn on the surface of the recording medium as drawing marks caused by continuous irradiation of laser light in the scanning direction, with irregular width stripes extending in a first direction. This results in high resolution in a second direction perpendicular to the direction of extension of the stripes. On the other hand, in the first direction parallel to the direction of extension of the stripes, the resolution is lower than in the second direction. However, since drawing using continuous irradiation of laser light can be performed using heat transfer, it is possible to obtain the desired image quality with lower power compared to drawing using pulsed irradiation of laser light.

[0007] A method for forming a drawing according to a second aspect of this disclosure is a method for forming a drawing by irradiating a recording medium, in which a plurality of thermal recording layers having different colors and light absorption wavelength bands in a colored state are stacked with an insulating layer in between, with a laser. This formation method includes a drawing step of forming a drawing by continuously irradiating the recording medium with laser light in the scanning direction and forming irregular stripe patterns extending in a first direction as drawing marks on the plurality of thermal recording layers.

[0008] In the method for forming a drawing according to the second aspect of this disclosure, a laser beam is continuously irradiated onto the recording medium in the scanning direction, and a drawing is formed on a plurality of thermal recording layers by forming irregularly sized stripe patterns extending in a first direction as drawing marks. This results in high resolution in a second direction perpendicular to the direction of extension of the stripe patterns. On the other hand, in the first direction parallel to the direction of extension of the stripe patterns, the resolution is lower than in the second direction. However, since drawing using continuous irradiation of laser beams can be performed using heat transfer, it is possible to obtain the desired image quality with lower power compared to drawing using pulsed irradiation of laser beams.

[0009] In the drawing relating to the first aspect described above, the recording medium is a laminate, and among the multiple thermal recording layers contained in this laminate, the first thermal recording layer has irregular stripe patterns extending in a first direction as drawing marks by laser irradiation. Since drawing on the first thermal recording layer by laser irradiation can perform stripe-like drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-like drawing using pulsed laser irradiation.

[0010] In the method for forming a drawing according to the second aspect described above, the recording medium is a laminate, and the method includes irradiating a first thermal recording layer among a plurality of thermal recording layers contained in the laminate with laser light to form a striped pattern of irregular width extending in a first direction as a drawing mark. Since drawing by irradiating the first thermal recording layer with laser light can perform striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed laser light irradiation. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a diagram showing a schematic configuration example of a drawing system according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a diagram showing a schematic example of the drawing section in Figure 1. [Figure 3]Figure 3 is a diagram showing an example of the cross-sectional configuration of the recording medium shown in Figure 2. [Figure 4] Figure 4(A) shows an example of the change in laser power over time. Figure 4(B) shows an example of a drawing trace. [Figure 5] Figure 5(A) shows an example of the change in laser power over time. Figure 5(B) shows an example of a drawing trace. [Figure 6] Figure 6(A) shows an example of the change in laser power over time. Figure 6(B) shows an example of a drawing trace. [Figure 7] Figure 7 shows an example of a drawing formed when laser light is shone onto the recording medium shown in Figure 2. [Figure 8] Figure 8 shows an example of image data obtained by capturing the drawing in Figure 7. [Figure 9] Figure 9 shows an example of the spatial frequency spectrum of the image data from Figure 8. [Figure 10] Figure 10(A) shows an example of a measurement area specified in the image data. Figure 10(B) shows an example of the peak ratio (intensity ratio at the peak position) in each measurement area. [Figure 11] Figure 11 is a diagram showing one modified example of the schematic configuration of a drawing system according to one embodiment of the present disclosure. [Figure 12] Figure 12(A) shows an example of image data of a drawing formed by irradiating a recording medium with laser light using the drawing system shown in Figure 11. Figure 12(B) shows an example of the spatial frequency spectrum of the image data. [Figure 13] Figure 13 is a diagram showing a modified example of the schematic configuration of a drawing system according to one embodiment of the present disclosure. [Figure 14] Figure 14 is a diagram showing one modified example of the schematic configuration of a drawing system according to one embodiment of the present disclosure. [Figure 15] Figure 15 shows an example of a perspective view of a laminated structure equipped with the recording medium shown in Figure 3. [Figure 16]Figure 16 shows an example of a cross-sectional configuration along line AA in Figure 15. [Figure 17] Figure 17 shows a modified example of the cross-sectional configuration along line AA in Figure 15. [Figure 18] Figure 18 shows a modified example of the cross-sectional configuration along line AA in Figure 15. [Figure 19] Figure 19 shows a modified example of the cross-sectional configuration along line AA in Figure 15. [Figure 20] Figure 20 shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 21] Figure 21 is a diagram showing a schematic example of the drawing section of Figure 20. [Figure 22] Figure 22 shows a modified example of the schematic configuration of the drawing system shown in Figure 1. [Figure 23] Figure 23 shows an example of a drawing formed by irradiating the laminated material shown in Figure 15 with laser light. [Figure 24] Figure 24 is a diagram showing a schematic example of the drawing section in Figure 22. [Figure 25] Figure 25 is a diagram showing a modified example of the schematic configuration of the drawing section in Figure 21. [Figure 26] Figure 26 is a diagram illustrating an example of a drawing method in a drawing system equipped with the drawing unit shown in Figure 25. [Modes for carrying out the invention]

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings, in the following order. The following description is one specific example of the present disclosure, and the present disclosure is not limited to the following embodiments. In the following, the same or corresponding parts will be denoted by the same reference numerals. 1. Embodiment An example of continuously irradiating a recording medium with laser light. 2. Variations Variation A: An example of rotating the stage by θ. Modification B: Example using an XY scanner Modification C: An example of continuously irradiating a laminated body equipped with a recording medium with laser light. Modification D: Example in which a laser marking layer is provided on the laminate. Modification E: An example where the optical axes of the light from each light source are offset from each other.

[0013] <1. Embodiment> [composition] A drawing system 100 according to one embodiment of the present disclosure will be described. Figure 1 shows a schematic example of the drawing system 100. The drawing system 100 is capable of writing (drawing) and erasing information on the recording medium 10, which will be described later. For example, the drawing system 100 is capable of converting image data (hereinafter referred to as "input image data"), which is input from an external source and described in a device-dependent color space, into image data (hereinafter referred to as "drawing image data") described in the color space of the recording medium 10.

[0014] Here, the device-dependent color space is, for example, an RGB color space such as sRGB or Adobe® RGB. The color space of the recording medium 10 is the color space inherent to the recording medium 10 as a characteristic. The drawing system 100 can further perform drawing on the recording medium 10 by, for example, converting the drawing image data obtained by the conversion into the output setting value of the drawing unit 150 (described later), and inputting the output setting value obtained by the conversion into the drawing unit 150. Below, the drawing system 100 will be described first, and then the recording medium 10 will be described.

[0015] (Drawing system 100) The drawing system 100 includes, for example, a communication unit 110, an input unit 120, a display unit 130, a storage unit 140, a drawing unit 150, and an information processing unit 160. The drawing system 100 is connected to a network, for example, via the communication unit 110. The network is, for example, a communication line such as a LAN or WAN. Terminal devices are connected to the network, for example. The drawing system 100 is configured to communicate with terminal devices via the network. The terminal devices are, for example, mobile terminals, and are configured to communicate with the drawing system 100 via the network.

[0016] The communication unit 110 is capable of communicating with external devices such as terminal devices. The communication unit 110 can, for example, transmit input image data received from an external device such as a mobile terminal to the information processing unit 160. The input image data is data in which the grayscale values ​​of each drawing coordinate are described in a device-dependent color space. In the input image data, the grayscale values ​​of each drawing coordinate are composed of, for example, 8-bit red grayscale values, 8-bit green grayscale values, and 8-bit blue grayscale values.

[0017] The input unit 120 is capable of receiving input from the user (for example, execution instructions, data input, etc.). The input unit 120 is capable of transmitting the information entered by the user to the information processing unit 160. The display unit 130 is capable of displaying screen data based on various screen data created by the information processing unit 160. The display unit 130 is composed of, for example, a liquid crystal panel or an organic EL (Electro-Luminescence) panel.

[0018] The memory unit 140 stores, for example, various programs. The memory unit 140 stores, for example, a program that converts input image data described in a device-dependent color space into drawing image data described in the color space of the recording medium 10. The drawing image data is, for example, data in which the gradation values ​​of each drawing coordinate are described in the color space of the recording medium 10. When the color space of the recording medium 10 is the Leuco color space, the gradation values ​​of each drawing coordinate in the drawing image data are composed of, for example, 8-bit magenta gradation values, 8-bit cyan gradation values, and 8-bit yellow gradation values. The memory unit 140 stores, for example, a program that derives output setting values ​​for the drawing unit 150 for each drawing coordinate based on the gradation values ​​of the drawing image data obtained by the conversion. In Figure 1, these programs are collectively represented as program 141.

[0019] The information processing unit 160 is configured to include, for example, a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit), and executes various programs (for example, program 141) stored in the memory unit 140. The information processing unit 160 can execute a series of procedures described in program 141 once program 141 is loaded, for example.

[0020] Next, the drawing unit 150 will be described. Figure 2 shows a schematic example of the drawing unit 150's configuration. The drawing unit 150 includes, for example, a signal processing circuit 51, a laser drive circuit 52, a light source unit 53, an X scanner drive circuit 54, an X scanner unit 55, a Y stage drive circuit 56, and a Y stage 57. The drawing unit 150 can perform drawing on the recording medium 10 by controlling the output of the light source unit 53 based on a voltage value file (list of command voltage values) input from the information processing unit 160.

[0021] The signal processing circuit 51 is capable of acquiring a voltage value file (a list of command voltage values) input from the information processing unit 160 as an image signal Din. The signal processing circuit 51 is capable of generating a pixel signal Dout from the image signal Din, for example, according to the scanner operation of the X scanner unit 55. The pixel signal Dout causes the light source unit 53 (for example, each of the light sources 53A, 53B, and 53C described later) to output laser light with power corresponding to the command voltage value. Together with the laser drive circuit 52, the signal processing circuit 51 is capable of controlling the peak value of the current applied to the light source unit 53 (for example, each of the light sources 53A, 53B, and 53C) according to the pixel signal Dout.

[0022] The laser driving circuit 52 is capable of driving each of the light sources 53A, 53B, and 53C of the light source unit 53 according to, for example, the pixel signal Dout. The laser driving circuit 52 is capable of controlling the brightness (brightness / darkness) of the laser light in order to draw an image corresponding to the pixel signal Dout. The laser driving circuit 52 includes, for example, a driving circuit 52A for driving light source 53A, a driving circuit 52B for driving light source 53B, and a driving circuit 52C for driving light source 53C. The light sources 53A, 53B, and 53C are capable of drawing on the recording medium 10 by outputting laser light with power corresponding to the command voltage value to the recording medium 10. The light sources 53A, 53B, and 53C are capable of emitting laser light in the near-infrared region. Light source 53A is, for example, a semiconductor laser that emits laser light La with an emission wavelength λ1. Light source 53B is, for example, a semiconductor laser that emits laser light Lb with an emission wavelength λ2. The light source 53C is, for example, a semiconductor laser that emits laser light Lc with an emission wavelength λ3.

[0023] The light source unit 53 has multiple light sources (for example, three light sources 53A, 53B, and 53C) with different emission wavelengths in the near-infrared region. Each light source (for example, each light source 53A, 53B, and 53C) is capable of generating laser light that includes wavelengths corresponding to the optical absorption wavelength band of the photothermal conversion agent (described later) contained in the recording medium 10. The light source unit 53 further has an optical system that combines multiple laser beams (for example, three laser beams La, Lb, and Lc) emitted from multiple light sources (for example, three light sources 53A, 53B, and 53C). Here, "combining" means scanning multiple laser beams with a single galvanometer. This optical system is capable of outputting the combined light (laser beam Lm) of the multiple laser beams La, Lb, and Lc (laser beam Lm) to the X scanner unit 55, for example, so that multiple irradiation spots Pa, Pb, and Pc generated on the recording medium 10 by the multiple laser beams La, Lb, and Lc overlap each other on the Y stage 57. The X-axis direction is perpendicular to the movement direction (Y-axis direction) of the Y-stage 57 and parallel to the scanning direction of the 1-axis scanner 55a, which will be described later. The light source unit 53 has, for example, two reflective mirrors 53a and 53d and two dichroic mirrors 53b and 53c as such an optical system.

[0024] The laser beams La and Lb emitted from the two light sources 53A and 53B are, for example, made nearly parallel light (collimated light) by a collimating lens. Then, for example, the laser beam La is reflected by the reflective mirror 53a and also by the dichroic mirror 53b, while the laser beam Lb is transmitted through the dichroic mirror 53b. As a result, the laser beam La and the laser beam Lb are combined. The combined light of the two laser beams La is transmitted through the dichroic mirror 53c.

[0025] The laser light Lc emitted from the light source 53C is, for example, made into nearly parallel light (collimated light) by a collimating lens. Then, the laser light Lc is reflected by, for example, a reflective mirror 53d and also by a dichroic mirror 53c. As a result, the combined light that has passed through the dichroic mirror 53c and the laser light Lc reflected by the dichroic mirror 53c are combined. The light source unit 53 is capable of outputting the light (laser light Lm) obtained by the above optical system to the X scanner unit 55.

[0026] The X-scanner drive circuit 54 can drive the X-scanner unit 55 based on a control signal input from, for example, the signal processing circuit 51. Furthermore, if, for example, the X-scanner drive circuit 54 receives a signal from the X-scanner unit 55 regarding the illumination angle of a single-axis scanner 55a (described later), it can drive the X-scanner unit 55 to achieve a desired illumination angle based on that signal.

[0027] The X-scanner unit 55 is capable of scanning the laser light Lm incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10. The X-scanner unit 55 includes, for example, a 1-axis scanner 55a and an fθ lens 55b. The 1-axis scanner 55a is a galvano mirror that scans the laser light Lm incident from the light source unit 53 in the X-axis direction on the surface of the recording medium 10 based on a drive signal input from the X-scanner drive circuit 54. The fθ lens 55b is capable of converting the constant velocity rotational motion of the 1-axis scanner 55a into the constant velocity linear motion of a spot moving on the focal plane (the surface of the recording medium 10).

[0028] The Y-stage drive circuit 56 can drive the Y-stage 57 based on a control signal input from, for example, the signal processing circuit 51. By displacing the Y-stage 57 in the Y-axis direction at a predetermined speed, the recording medium 10 placed on the Y-stage 57 can be moved in the Y-axis direction relative to the X-scanner unit 55 at a predetermined speed. Through the coordinated operation of the X-scanner unit 55 and the Y-stage 57, the laser beam Lm raster scans the surface of the recording medium 10.

[0029] (Recording medium 10) Next, the recording medium 10 will be described.

[0030] Figure 3 shows an example of the configuration of each layer included in the recording medium 10. The recording medium 10 is a reversible recording medium that can write (draw) and erase information. The recording medium 10 is a sheet-like or plate-like recording medium that is rectangular in plan view. In the recording medium 10, the X direction is parallel to one edge of the recording medium 10, and the Y direction is parallel to the other edge of the recording medium 10 that is perpendicular to the aforementioned edge. The recording medium 10 comprises a plurality of recording layers 13, 15, and 17 that have different color tones from each other. The recording layers 13, 15, and 17 correspond to a specific example of the "first thermal recording layer" according to one embodiment of this disclosure. For example, the recording medium 10 has a structure (laminated body) in which a base layer 12, a recording layer 13, a heat insulating layer 14, a recording layer 15, a heat insulating layer 16, a recording layer 17, and a protective layer 18 are laminated on a substrate 11 in this order. The protective layer 18 is positioned opposite the substrate 11 via the base layer 12, recording layer 13, heat insulating layer 14, recording layer 15, heat insulating layer 16, and recording layer 17. The protective layer 18 may be positioned on the outermost surface of the recording medium 10, or another layer may be positioned on the outermost surface of the recording medium 10.

[0031] The three recording layers 13, 15, and 17 are arranged in the order of recording layer 13, recording layer 15, and recording layer 17 from the substrate 11 side. The two heat insulating layers 14 and 16 are arranged in the order of heat insulating layer 14 and heat insulating layer 16 from the substrate 11 side. The base layer 12 is formed in contact with the surface of the substrate 11. The protective layer 18 is formed on the outermost surface of the recording medium 10.

[0032] The substrate 11 supports each recording layer 13, 15, 17 and each heat insulating layer 14, 16. The substrate 11 functions as a substrate for forming each layer on its surface. The substrate 11 may be light-transmitting or light-impermeable. If it is light-impermeable, the surface color of the substrate 11 may be, for example, white or a color other than white.

[0033] The base material 11 may be a card or a film. The base material 11 may have a design, picture, photograph, text, or a combination of two or more of these printed on one of its main surfaces where the recording layer 13 is provided.

[0034] The substrate 11 may be, for example, a substrate with high rigidity such as a wafer, or a flexible thin-layer glass, film, or paper. By using a flexible substrate as the substrate 11, a flexible (bendable) recording medium 10 can be realized. Examples of constituent materials for the substrate 11 include inorganic materials, metallic materials, or plastics. Examples of inorganic materials include silicon (Si) and silicon dioxide (SiO₂). X ), silicon nitride (SiN X ) and aluminum oxide (AlO X It includes at least one selected from the group consisting of ) etc. Silicon oxide includes glass and spin-on glass (SOG), etc. Metallic materials include, for example, at least one selected from the group consisting of aluminum (Al), nickel (Ni), stainless steel, etc.

[0035] The base material 11 may include, for example, plastic. The base material 11 may optionally contain at least one selected from the group consisting of colorants, antistatic agents, flame retardants, and surface modifiers.

[0036] The plastic used in the base material 11 includes, for example, at least one selected from the group consisting of ester resins, amide resins, olefin resins, vinyl resins, acrylic resins, imide resins, styrene resins, and engineering plastics. If the base material 11 contains two or more resins, these two or more resins may be mixed, copolymerized, or laminated.

[0037] The above ester resin includes, for example, at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. The above amide resin includes, for example, at least one selected from the group consisting of nylon 6, nylon 66, and nylon 610. The above olefin resin includes, for example, at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP). The above vinyl resin includes, for example, polyvinyl chloride (PVC).

[0038] The above acrylic resin includes, for example, at least one selected from the group consisting of polyacrylate, polymethacrylate, and polymethyl methacrylate (PMMA). The imide resin includes, for example, at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), and polyetherimide (PEI). The above styrene resin includes, for example, at least one selected from the group consisting of polystyrene (PS), high-impact polystyrene, acrylonitrile-styrene resin (AS resin), and acrylonitrile-butadiene-styrene resin (ABS resin). The above-mentioned engineering plastics include, for example, at least one selected from the group consisting of polycarbonate (PC), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyetherketone (PEK), polyether-etherketone (PEEK), polyphenylene oxide (PPO), and polyethersulfite.

[0039] The base layer 12 has the function of improving the adhesion between the recording layer 13 and the substrate 11. The base layer 12 is made of, for example, a light-transmitting material. A moisture-resistant barrier layer or a light-resistant barrier layer may be provided above or below the base layer 12 or the substrate 11. In addition, an insulating layer may be provided between the base layer 12 and the recording layer 13.

[0040] The three recording layers 13, 15, and 17 can reversibly change their state between a colored state and a decolorized state. The three recording layers 13, 15, and 17 are configured such that their colors in the colored state are different from each other. The three recording layers 13, 15, and 17 are thermal recording layers composed of a color-developing compound, a photothermal converter, and a smear / decolorizer, respectively. The three recording layers 13, 15, and 17 are composed of a color-developing compound whose colors in the colored state are different from each other, and a photothermal converter whose light absorption wavelength bands are different from each other. In the three recording layers 13, 15, and 17, the color-developing compound, the photothermal converter, and the smear / decolorizer are dispersed in a matrix resin (polymer material). The recording layers 13, 15, and 17 may each be a laminate comprising a layer containing a color-developing compound and a stimulating / dechromizing agent, and a layer containing a photothermal converter, or they may be a single-layer structure containing a color-developing compound, a photothermal converter, and a stimulating / dechromizing agent.

[0041] For example, leuco dyes are used as color-developing compounds. Leuco dyes become colored when heated by binding with a stimulating / dechromizing agent, or they become decolorized when separated from the stimulating / dechromizing agent. The color tones of the leuco dyes contained in each recording layer 13, 15, and 17 differ for each recording layer 13, 15, and 17. The leuco dye contained in recording layer 13 develops magenta color when heated by binding with a stimulating / dechromizing agent. The leuco dye contained in recording layer 15 develops cyan color when heated by binding with a stimulating / dechromizing agent. The leuco dye contained in recording layer 17 develops yellow color when heated by binding with a stimulating / dechromizing agent. The positional relationship of the three recording layers 13, 15, and 17 is not limited to the above example. Also, the three recording layers 13, 15, and 17 become transparent when decolorized. As a result, the recording medium 10 can record images using a wide color gamut.

[0042] The photothermal converter is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. In this specification, the near-infrared region refers to the wavelength range of 700 nm to 2500 nm. It is preferable to select a photothermal converter that has a narrow light absorption band in the near-infrared region and whose light absorption bands do not overlap with each other in the recording layers 13, 15, and 17.

[0043] The insulating layer 14 is designed to reduce heat transfer between the recording layer 13 and the recording layer 15. The insulating layer 16 is designed to reduce heat transfer between the recording layer 15 and the recording layer 17.

[0044] The thermal insulation layers 14 and 16 include, for example, a matrix resin (polymer material) having general light transmission properties. Specific materials include, for example, at least one selected from the group consisting of acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymer resins, ethylcellulose resins, polystyrene resins, styrene copolymer resins, phenoxy resins, polyester resins, aromatic polyester resins, polyurethane resins, polycarbonate resins, polyacrylic acid ester resins, polymethacrylate resins, acrylic acid copolymer resins, maleic acid polymer resins, polyvinyl alcohol resins, modified polyvinyl alcohol resins, hydroxyethylcellulose resins, carboxymethylcellulose resins, and starch. The thermal insulation layers 14 and 16 may also contain various additives, such as ultraviolet absorbers.

[0045] The heat insulating layers 14 and 16 may be, for example, UV-curable resin layers. The UV-curable resin layer contains a UV-curable resin composition that has undergone a polymerization reaction and solidified. More specifically, for example, the UV-curable resin layer contains a polymer of a polymerizable compound and a polymer that has undergone a structural change when a polymerization initiator generates active species upon irradiation with external energy (ultraviolet light). The UV-curable resin composition includes, for example, at least one selected from the group consisting of radical polymerization type UV-curable resin compositions and cationic polymerization type UV-curable resin compositions. The UV-curable resin composition may optionally contain at least one selected from the group consisting of sensitizers, fillers, stabilizers, leveling agents, defoamers, and viscosity modifiers. The UV-curable resin composition may be a UV-curable resin composition for hard coatings. The UV-curable resin composition may be an acrylic UV-curable resin composition.

[0046] The insulating layers 14 and 16 may contain translucent inorganic materials. For example, using porous silica, alumina, titania, carbon, or composites thereof is preferable as it results in low thermal conductivity and a high insulating effect. The insulating layers 14 and 16 can be formed, for example, by the sol-gel method.

[0047] The thickness of the thermal insulation layers 14 and 16 is preferably 3 μm to 100 μm, more preferably 5 μm to 50 μm. If the thickness of the thermal insulation layers 14 and 16 is 3 μm or more, a sufficient thermal insulation effect can be obtained. On the other hand, if the thickness of the thermal insulation layers 14 and 16 is 100 μm or less, a decrease in light transmittance can be suppressed. Furthermore, a decrease in the bending resistance of the recording medium 10 can be suppressed, making it less likely for defects such as cracks to occur.

[0048] The pencil hardness of the surfaces of the heat insulating layers 14 and 16 is preferably 2B or higher, more preferably H or higher. When the pencil hardness of the surfaces of the heat insulating layers 14 and 16 is 2B or higher, the density of the heat insulating layers 14 and 16 is high, and the diffusion of substances through the heat insulating layers 14 and 16 can be further suppressed. For example, when the pencil hardness of the surfaces of the heat insulating layers 14 and 16 is 2B or higher, the diffusion of color-developing compounds through the heat insulating layers 14 and 16 can be further suppressed. Therefore, the change in hue of the recording layers 13, 15, and 17 during long-term storage can be further suppressed. As the heat insulating layers 14 and 16 having the above-mentioned pencil hardness, ultraviolet-curable resin layers are preferred.

[0049] The pencil hardness of the surface of the insulating layer 14 is measured as follows: First, the recording medium 10 is disassembled to expose the surface of the insulating layer 14. Next, the pencil hardness of the surface of the insulating layer 14 is measured in accordance with JIS K5600-5-4. This measurement is performed in a standard atmosphere with a temperature of 23 ± 1°C and a relative humidity of 50 ± 5%. The pencil hardness of the surface of the insulating layer 16 is measured using the same procedure as the pencil hardness of the surface of the insulating layer 14.

[0050] The protective layer 18 is for protecting the surface of the recording medium 10 and functions as an overcoat layer for the recording medium 10. The heat insulating layers 14, 16 and the protective layer 18 are made of transparent material. The recording medium 10 may have, for example, a relatively rigid resin layer (e.g., a PEN resin layer) directly beneath the protective layer 18. The protective layer 18 may also include a moisture-resistant barrier layer or a light-resistant barrier layer. Furthermore, the protective layer 18 may include any functional layer. The protective layer 18 is formed using, for example, at least one of ultraviolet-curable resins and thermosetting resins. The protective layer 18 is preferably a hard coat layer. The thickness of the protective layer 18 is, for example, 0.1 μm or more and 20 μm or less.

[0051] In the recording medium 10, an adhesive layer may be provided between two adjacent layers to bond the two adjacent layers together. The adhesive layer may also function as a heat insulating layer 14, 16. The adhesive layer contains an adhesive. The adhesive contains, for example, at least one selected from the group consisting of acrylic resins, silicone resins, urethane resins, epoxy resins, and elastomer materials.

[0052] Examples of leuco dyes include existing dyes for thermal paper. Specifically, one example is the compound shown in Chemical Formula 1 below, which contains, for example, an electron-donating group in its molecule. [ka]

[0053] There are no particular restrictions on the color-developing compounds, and they can be appropriately selected depending on the purpose. Specific examples of color-developing compounds include, in addition to the compounds shown in Formula 1 above, fluorane compounds, triphenylmethanephthalide compounds, azaphthalide compounds, phenothiazine compounds, leucoauramine compounds, and indolinophthalide compounds. In addition, for example, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-di(n-butylamino)fluorane, 2-anilino-3-methyl-6-(Nn-propyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isopropyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-isobutyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(Nn-amyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-sec-butyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(Nn-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-( N-iso-amyl-N-ethylamino)fluorane, 2-anilino-3-methyl-6-(Nn-propyl-N-isopropylamino)fluorane, 2-anilino-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-anilino-3-methyl-6-(N-methyl-p-toluidino)fluorane, 2-(m-trichloromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trifluoromethylanilino)-3-methyl-6-diethylaminofluorane, 2-(m-trichloromethylanilino)-3-methyl-6-(N-cyclohexyl-N-methylamino)fluorane, 2-(2,4-dimethylanilino)-3-methyl-6-diethylaminofluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-ethylanilino)fluorane, 2-(N-ethyl-p-toluidino)-3-methyl-6-(N-propyl-p-toluidino)fluorane, 2-anilino-6-(Nn-hexyl-N-ethylamino)fluorane, 2-(o-chloroanilino)-6-diethylaminofluorane, 2-(o-chloroanilino)-6-dibutylaminofluorane, 2-(m-trifluoromethylanilino)-6-diethylaminofluorane, 2,3-dimethyl-6-dimethylaminofluorane, 3-methyl-6-(N-ethyl-p-toluidino)fluorane, 2-chloro-6 -Diethylaminofluorane, 2-bromo-6-diethylaminofluorane, 2-chloro-6-dipropylaminofluorane, 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2-chloro-6-(N-ethyl-N-isoamylamino)fluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-(o-chloroanilino)-3-chloro-6-cyclohexylaminofluorane, 2-(m-trifluoromethylanilino)-3-chloro-6-diethylaminofluorane, 2-(2,3-dichloroanilino)-3-chloro-6-diethylaminofluorane, 1,2-Benzo-6-diethylaminofluorane, 3-diethylamino-6-(m-trifluoromethylanilino)fluorane, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 3-(1-octyl- 2-methylindole-3-yl)-3-(2-ethoxy-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(2-methyl-4-diethylaminophenyl)-7-azaphthalide, 3-(1-ethyl-2-methylin Dol-3-yl)-3-(4-diethylaminophenyl)-4-azaphthalide, 3-(1-ethyl-2-methylindole-3-yl)-3-(4-Nn-amyl-N-methylaminophenyl)-4-azaphthalide, 3-(1-methyl-2-methylindole-3-yl)-3-(2-hexyloxy-4-diethylaminophenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl) Phenyl)-4-azaphthalide, 3,3-bis(2-ethoxy-4-diethylaminophenyl)-7-azaphthalide, 2-(p-acetylanilino)-6-(Nn-amyl-Nn-butylamino)fluorane, 2-benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-benzylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-benzylamino-6-(N-ethyl-2,4-dimethylanilino)fluorane, 2-benzylamino-6-(N-methyl-p-toluidino)fluorane, 2-benzylamino-6-(N-ethyl-p-toluidino)fluorane, 2-(di-p-methylbenzylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-(α-phenylethylamino)-6-(N-ethyl-p-toluidino)fluorane, 2-methylamino-6-(N-methylanilino)fluorane, 2-methylamino-6-(N-ethylanilino)fluorane, 2-methylamino-6-(N-propylanilino)fluorane , 2-ethylamino-6-(N-methyl-p-toluidino)fluorane, 2-methylamino-6-(N-methyl-2,4-dimethylanilino)fluorane, 2-ethylamino-6-(N-ethyl-2,4-dimethylanilino)fluorane, 2-dimethylamino-6-(N-methylanilino)fluorane, 2-dimethylamino-6-(N-ethylanilino)fluorane, 2-diethylamino-6-(N-methyl-p-toluidino)fluorane, 2-diethylamino-6-(N-ethyl-p-toluidino)fluorane, 2-dipropylamino-6-(N-methyl Fluoranilino)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 (Tyl-p-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,Examples include 2-benzo-6-(N-ethyl-N-isoamylamino)fluorane, 1,2-benzo-6-dibutylaminofluorane, 1,2-benzo-6-(N-methyl-N-cyclohexylamino)fluorane, and 1,2-benzo-6-(N-ethyl-N-toluidino)fluorane. In the recording layers 13, 15, and 17, one of the above compounds may be used alone as a color-forming compound, or two or more thereof may be used in combination.

[0054] The color-developing / decoloring agent is used, for example, for developing the color of a colorless color-forming compound or decoloring a color-forming compound that exhibits a predetermined color. Examples of the color-developing / decoloring agent include phenol derivatives, salicylic acid derivatives, and urea derivatives. Specifically, the color-developing / decoloring agent may contain, for example, a compound represented by the following Chemical Formula 2.

Chemical Formula

[0055] The color developer may contain, for example, a compound represented by the following Chemical Formula 3.

Chemical Formula

[0056] When formulas 2 and 3 contain hydrocarbon groups, these hydrocarbon groups are a general term for groups composed of carbon (C) and hydrogen (H), and may be saturated hydrocarbon groups or unsaturated hydrocarbon groups. Saturated hydrocarbon groups are aliphatic hydrocarbon groups that do not have multiple carbon-carbon bonds, while unsaturated hydrocarbon groups are aliphatic hydrocarbon groups that have multiple carbon-carbon bonds (carbon-carbon double bonds or carbon-carbon triple bonds).

[0057] If chemical formulas 2 and 3 contain a hydrocarbon group, the hydrocarbon group may be in the form of 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, etc.

[0058] (X containing one benzene ring) 0 , X 1 ) X in chemical formula 2 0 and X in chemical 3 1 This is, for example, a divalent group containing one benzene ring. This divalent group is represented, for example, by the following chemical formula 4. [ka] (However, in Chemical Formula 4, X 21 It can be there or not, X 21 If X 21 X is a divalent group. 22 It can be there or not, X 22 If X 22 R is a divalent group. 21 is a single-valued base. n21 is an integer from 0 to 4. If n21 is an integer from 2 to 4, then R 21These elements may be identical or different. (* indicates a connection point.)

[0059] In chemical formula 4, X relative to the benzene ring 21 and X 22 The bonding position of X is not limited. That is, X relative to the benzene ring. 21 and X 22 The bond position may be the ortho, meta, or para position.

[0060] The above divalent group containing one benzene ring is preferably represented by the following chemical formula 5 from the viewpoint of improving high-temperature and high-humidity storage characteristics. [ka] (However, in chemical formula 5, R 22 is a single-valued base. n²² is an integer from 0 to 4. If n²² is an integer from 2 to 4, then R 22 These elements may be identical or different. (* indicates a connection point.)

[0061] X in chemical formula 2 0 If is a divalent group containing one benzene ring, then in chemical formula 5, Z relative to the benzene ring. 01 and Z 02 The bonding position is not limited. That is, Z relative to the benzene ring. 01 and Z 02 The bond position may be the ortho, meta, or para position.

[0062] X in Chemical Formula 3 1 If is a divalent group containing one benzene ring, then in chemical formula 5, Z relative to the benzene ring. 11 and Z 12 The bonding position is not limited. That is, Z relative to the benzene ring. 11 and Z 12 The bond position may be the ortho, meta, or para position.

[0063] (X 21 , X 22) X in Chemical Formula 4 21 , X 22 Each of these groups can be a divalent group and is not particularly limited, but examples include hydrocarbon groups which may have substituents. The hydrocarbon groups are preferably in chain form, and normal alkyl chains are particularly preferred.

[0064] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0065] X in Chemical Formula 4 21 , X 22 When the normal alkyl group 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 number of carbon atoms in the normal alkyl group is 8 or less, the length of the normal alkyl group is short, so thermal disturbance is less likely to occur in the color developer during high-temperature storage, and the site that interacted with the color-developing compound such as leuco dye during color development is less likely to detach. Therefore, the color-developing compound such as leuco dye is less likely to lose its color during high-temperature storage, thus improving high-temperature storage stability.

[0066] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). 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 in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0067] (R 21 ) R in Chemical Formula 4 21 This can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have substituents.

[0068] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0069] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0070] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). 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 in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0071] (R 22 ) R in Chemical Formula 5 22 R in Chemical Formula 2 can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. 21 It is similar to that.

[0072] (X containing two benzene rings) 0 , X 1 ) X in chemical formula 2 0 and X in chemical 3 1 This is, for example, a divalent group containing two benzene rings. This divalent group is represented, for example, by the following chemical formula 6. [ka] (However, in chemical formula 6, X 31 It can be there or not, X 31 If X 31 X is a divalent group. 32 It can be there or not, X 32 If X 32 X is a divalent group. 33 It can be there or not, X 33 If X33 R is a divalent group. 31 , R 32 n31 and n32 are independent single-valued bases. n31 and n32 are independent integers from 0 to 4. If n31 is an integer from 2 to 4, then R 31 They may be the same or different. If n32 is an integer between 2 and 4, then R 32 These elements may be identical or different. (* indicates a connection point.)

[0073] In chemical formula 6, X relative to the benzene ring 31 and X 32 The bonding position of X is not limited. That is, X relative to the benzene ring. 31 and X 32 The bond position may be the ortho, meta, or para position. Similarly, in chemical formula 6, X on the benzene ring 32 and X 33 The bonding position of X is not limited. That is, X relative to the benzene ring. 32 and X 33 The bond position may be the ortho, meta, or para position.

[0074] The above divalent group containing two benzene rings is preferably represented by the following chemical formula 7 from the viewpoint of improving high-temperature and high-humidity storage characteristics. [ka] (However, in chemical formula 7, X 34 It is a divalent group. 33 , R 34 n33 and n34 are each independent and unvalued bases. n33 and n34 are each independent integers from 0 to 4. If n33 is an integer from 2 to 4, then R 33 They may be the same or different. If n34 is an integer between 2 and 4, then R 34 These elements may be identical or different. (* indicates a connection point.)

[0075] X in Chemical Formula 2 0 is a divalent group containing two benzene rings, in Chemical Formula 7, Z for the benzene ring 01 and X 34 binding position is not limited. That is, the binding position of Z 01 and X 34 to the benzene ring may be any of ortho, meta, and para positions. Similarly, in Chemical Formula 7, the binding position of Z 02 and X 34 to the benzene ring is not limited. That is, the binding position of Z 02 and X 34 to the benzene ring may be any of ortho, meta, and para positions.

[0076] X in Chemical Formula 3 1 is a divalent group containing two benzene rings, in Chemical Formula 7, Z for the benzene ring 11 and X 34 binding position is not limited. That is, the binding position of Z 11 and X 34 to the benzene ring may be any of ortho, meta, and para positions. Similarly, in Chemical Formula 7, the binding position of Z 12 and X 34 to the benzene ring is not limited. That is, the binding position of Z 12 and X 34 to the benzene ring may be any of ortho, meta, and para positions.

[0077] (X 31 , X 32 , X 33 ) X in Chemical Formula 6 31 , X 32 , X 33 are each independently a divalent group, which is not particularly limited, but for example, it is an optionally substituted hydrocarbon group. The hydrocarbon group is the same as X 21 , X 22 in the above Chemical Formula 4.

[0078] (X 34 ) X in Chemical Formula 7 34 X can be any divalent group and is not particularly limited, but an example is a hydrocarbon group which may have substituents. The hydrocarbon group is X in the above chemical formula 4. 21 , X 22 It is similar to that.

[0079] (R 31 , R 32 ) R in chemical formula 6 31 , R 32 R in the above formula 4 can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. 21 It is similar to that.

[0080] (R 33 , R 34 ) R in Chemical Formula 7 33 , R 34 R in the above formula 4 can be any monovalent group and is not particularly limited, but examples include a halogen group or a hydrocarbon group which may have a substituent. 21 It is similar to that.

[0081] (Y 01 , Y 02 ) Y in Chemical Formula 2 01 , Y 02 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group (-X), a carboxyl group (-COOH), an ester group (-COOR), or a hydrocarbon group which may have substituents.

[0082] Halogen groups include, for example, fluorine (-F), chlorine (-Cl), bromine (-Br), or iodine (-I).

[0083] The number of carbon atoms in the hydrocarbon group, which may have substituents, is, for example, 1 to 15, 1 to 13, 1 to 12, 1 to 10, 1 to 6, or 1 to 3.

[0084] Examples of substituents that may have a hydrocarbon group include halogen groups (e.g., fluorine groups) or alkyl groups having halogen groups (e.g., fluorine groups). 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 in the main chain of the hydrocarbon group) are substituted with an element such as oxygen.

[0085] In chemical formula 2, (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 It is preferable that one of them is a hydroxyl group (-OH). (Y 01 ) n01 one of the following, and / or (Y 02 ) n02 One of these groups is a hydroxyl group (-OH), which improves label quality and lightfastness.

[0086] (Y 11 , Y 12 , Y 13 , Y 14 ) In chemical formula 3, Y relative to the benzene ring 11 and Y 12 The bonding position is not limited. That is, Y relative to the benzene ring. 11 and Y 12 The bond position of can be any of the ortho, meta, or para positions. Similarly, in chemical formula 3, Y on the benzene ring 13 and Y 14 The bonding position is not limited. That is, Y relative to the benzene ring. 13 and Y 14 The bond position may be any of the ortho, meta, or para positions. In chemical formula 3, Y is attached to one of the benzene rings. 11 and Y 12 The bond position of and Y relative to the other benzene 13and Y 14 The bonding position may be the same as or different from that position.

[0087] Y in Chemical Formula 3 11 , Y 12 , Y 13 , Y 14 Each of these is independently, for example, a hydrogen group (-H), a hydroxyl group (-OH), a halogen group, a carboxyl 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 Y in the above chemical formula 2, respectively. 01 , Y 02 It is similar to that.

[0088] In chemical formula 3, Y 11 and / or Y 13 It is preferable that it is a hydroxyl group (-OH). 11 and / or Y 13 The presence of a hydroxyl group (-OH) improves both label quality and lightfastness.

[0089] (Z 01 , Z 02 ) Z in Chemical Formula 2 01 , Z 02 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 01 , Z 02 It is preferable that it is a urea bond. 01 If it 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 If the bond 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.

[0090] (Z 11 , Z 12 ) Z in Chemical 3 11 , Z 12 These are, independently of each other, for example, urea bonds (-NHCONH-), amide bonds (-NHCO-, -OCHN-), or hydrazide bonds (-NHCOCONH-). From the viewpoint of improving high temperature and high humidity storage characteristics, Z 11 , Z 12 It is preferable that it is a urea bond. 11 If it 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 If the bond 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.

[0091] Other color-reducing agents include, for example, 4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis(o-methylphenol), 4,4'-secondarybutylidenebisphenol, 4,4'-isopropylidenebis(2-tert-butylphenol), p-zinc nitrobenzoate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanuric acid, 2,2-(3,4'-dihydroxydiphenyl)propane, bis(4-hydroxy-3-methylphenyl)sulfide, 4-{β-( p-Methoxyphenoxy)ethoxy}salicylic acid, 1,7-bis(4-hydroxyphenylthio)-3,5-dioxaheptane, 1,5-bis(4-hydroxyphenithio)-5-oxapentane, monobenzyl phthalate monocalcium salt, 4,4'-cyclohexyllidenediphenol, 4,4'-isopropylidenebis(2-chlorophenol), 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(6-tert-butyl-2-methyl)phenol, 1,1,3-tris(2-methyl (4-hydroxy-5-tert-butylphenyl)butane, 1,1,3-tris(2-methyl-4-hydroxy-5-cyclohexylphenyl)butane, 4,4'-thiobis(6-tert-butyl-2-methyl)phenol, 4,4'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone (4-hydroxy-4'-isopropoxydiphenylsulfone), 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, p-hydroxybenzoate isopropyl, p-hydroxy Benzyl thiobenzoate, benzyl protocatechate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis(4-hydroxyphenylthio)-propane, N,N'-diphenylthiourea, N,N'-di(m-chlorophenyl)thiourea, salicylanilide, methyl bis(4-hydroxyphenyl)acetate, benzyl bis(4-hydroxyphenyl)acetate, 1,3-bis(4-hydroxycumyl)benzene, 1,4-bis(4-hydroxycumyl)benzene, 2,4'-diphenolsulfone, 2,2'-diallyl-4,4'-Diphenolsulfone, 3,4-Dihydroxyphenyl-4'-Methyldiphenylsulfone, Zinc 1-Acetyloxy-2-Naphthoate, Zinc 2-Acetyloxy-1-Naphthoate, Zinc 2-Acetyloxy-3-Naphthoate, α,α-Bis(4-Hydroxyphenyl)-α-Methyltoluene, Antipyrine complex of zinc thiocyanate, Tetrabromobisphenol A, Tetrabromobisphenol S, 4,4'-Thiobis(2-Methylphenol), 4,4'-Thiobis(2-Chlorophenol), Dodecylphosphonic acid, Tetradecylphosphonic acid, Hexadecylphosphonic acid, Octadecylphosphonic acid, Eicosylphosphonic acid, Docosylphosphonic acid, Tetracosylphosphonic acid, Hexacosylphosphonic acid, Octacosylphosphonic acid, α-Hydroxydodecylphosphonic acid Examples include hydroxytetradecylphosphonic acid, α-hydroxyhexadecylphosphonic acid, α-hydroxyoctadecylphosphonic acid, α-hydroxyeicosylphosphonic acid, α-hydroxydocosylphosphonic acid, α-hydroxytetracosylphosphonic acid, dihexadecyl phosphate, dioctadecyl phosphate, dieicosyl phosphate, didocosyl phosphate, monohexadecyl phosphate, monooctadecyl phosphate, monoeicosyl phosphate, monodocosyl phosphate, methylhexadecyl phosphate, methyloctadecyl phosphate, methyleicosyl phosphate, methyldocosyl phosphate, amylhexadecyl phosphate, octylhexadecyl phosphate, and laurylhexadecyl phosphate. For recording layers 13, 15, and 17, one of the above compounds may be used alone as a developer / color reducer, or two or more may be used in combination. ,

[0092] A photothermal converter is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. Preferably, the photothermal converter uses a near-infrared absorbing dye that has an absorption peak in the wavelength range of 700 nm to 2500 nm and has almost no absorption in the visible region. Specifically, examples include compounds having a phthalocyanine skeleton (phthalocyanine dyes), compounds having a naphthalocyanine skeleton (naphthalocyanine dyes), compounds having a squarylium skeleton (squarylium dyes), metal complexes such as dithio complexes, diimonium salts, aminium salts, and inorganic compounds. Examples of inorganic compounds include graphite, carbon black, metal powder particles, metal oxides such as cobalt tetroxide, iron oxide, chromium oxide, copper oxide, titanium black, and ITO, metal nitrides such as niobium nitride, metal carbides such as tantalum carbide, metal sulfides, or various magnetic powders. In addition, compounds having a cyanine skeleton with excellent light resistance and heat resistance (cyanine dyes) may also be used.

[0093] Excellent light resistance means that the material does not decompose when irradiated with a laser. Excellent heat resistance means that, for example, when the material is formed in film with a matrix resin (polymer material) and stored at, for example, 150°C for 30 minutes, the maximum absorption peak value of the absorption spectrum does not change by more than 20%. Examples of compounds having such a cyanine skeleton include those having at least one of the following counterions in the molecule: SbF6, PF6, BF4, ClO4, CF3SO3, and (CF6SO3)2N, and a methine chain containing a 5-membered ring or a 6-membered ring.

[0094] Cyanine dyes preferably possess both one of the above-mentioned counterions and cyclic structures such as five-membered and six-membered rings within the methine chain, but sufficient light resistance and heat resistance are ensured if at least one of them is present. Materials with excellent light resistance and heat resistance do not decompose when irradiated with a laser, as described above. One way to confirm light resistance is to measure the change in the absorption spectrum peaks during a xenon lamp irradiation test. If the rate of change after 30 minutes of irradiation is 20% or less, the light resistance can be judged to be good. One way to confirm heat resistance is to measure the change in the absorption spectrum peaks when stored at 150°C. If the rate of change after a 30-minute test is 20% or less, the heat resistance can be judged to be good.

[0095] The matrix resin (polymer material) is preferably one in which the color-developing compound, smear / decolorizing agent, and photothermal converter can be homogeneously dispersed. Furthermore, the matrix resin (polymer material) is preferably highly transparent in order to obtain high visibility of the information written on the recording layers 13, 15, and 17, and is preferably highly soluble in organic solvents, for example. Examples of matrix resins (polymer materials) include thermosetting resins and thermoplastic resins. Specifically, examples include polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylcellulose, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polycarbonate, polyacrylic acid ester, polymethacrylate ester, acrylic acid copolymer, maleic acid polymer, polyvinyl alcohol, modified polyvinyl alcohol, hydroxyethylcellulose, carboxymethylcellulose, and starch.

[0096] The recording layers 13, 15, and 17 are composed of at least one of the above-mentioned color-developing compound, stimulating / dechromizing agent, and photothermal converter. Preferably, the color-developing compound and stimulating / dechromizing agent contained in the recording layers 13, 15, and 17 are in a ratio of color-developing compound:stimulating / dechromizing agent = 1:2 (by weight). The amount of photothermal converter varies depending on the film thickness of the recording layers 13, 15, and 17. In addition to the above-mentioned materials, the recording layers 13, 15, and 17 may also be composed of various additives such as sensitizers and ultraviolet absorbers.

[0097] The ratio of the chromatic agent to the total amount of matrix resin (polymer material) is measured as follows: The composition of the chromatic agent and matrix resin (polymer material) in the recording layer is measured by mapping using a Fourier transform infrared spectrophotometer (micro FTIR). Alternatively, it can be calculated by measuring the weight while dissolving each in an appropriate organic solvent, taking advantage of the difference in solubility between the chromatic agent and the matrix resin (polymer material).

[0098] The protective layer 18 may have the function of suppressing the ingress of moisture, oxygen, or both into the recording layers 13, 15, and 17. The protective layer 18 covers the surface of the recording layer 17. The protective layer 18 has a density of, for example, 0.001 g / m². 2 / day or more 10g / m 2 It is preferable that the protective layer 18 has a water vapor transmission rate of less than or equal to 1 / day. Furthermore, it is preferable that the protective layer 18 has high transparency in order to obtain high visibility of the information written on the recording layers 13, 15, and 17, similar to the matrix resin (polymer material) that constitutes the recording layers 13, 15, and 17. An example of such a protective layer 18 is a laminated film in which an inorganic oxide film is provided on a substrate made of a plastic film. In a protective layer 18 configured as a laminated film of a plastic film and an inorganic oxide film, for example, the inorganic oxide film covers the recording layer 17 on the side (inside) of the recording layer 17 and the plastic film on the outside.

[0099] The base plastic film can be, for example, an industrial plastic film, and can be formed using at least one of polyethylene terephthalate (PET), polycarbonate (PC), and methyl methacrylate (PMMA). The thickness of the plastic film is preferably, for example, 5 μm to 100 μm.

[0100] Examples of inorganic oxide films include silicon oxide films (SiO2) deposited using methods such as sputtering and chemical vapor deposition (CVD). x (film), aluminum oxide film (AlO x (film) and silicon nitride film (SiN x Examples include a single layer or multilayer film using at least one of the films. The thickness of the protective layer 18 is preferably, for example, 10 nm or more and 1 μm or less.

[0101] Next, an example of writing information in the drawing system 100 will be described.

[0102] First, the user prepares an uncolored recording medium 10 and places it on the Y stage 57. Next, the user transmits input image data, described in the RGB color space, to the drawing system 100 via the network from a terminal device. When the drawing system 100 receives the input image data via the network, it executes the following drawing process.

[0103] First, when the information processing unit 160 receives input image data via the communication unit 110, it converts the input image data, which is described in the RGB color space, into leuco image data, which is described in the leuco color space. Next, the information processing unit 160 derives a voltage value file (a list of command voltage values) based on the gradation values ​​of each color at each drawing coordinate of the leuco image data obtained by the conversion. The information processing unit 160 then transmits the derived voltage value file (a list of command voltage values) to the drawing unit 150.

[0104] The signal processing circuit 51 of the drawing unit 150 acquires a voltage value file (list of command voltage values) input from the information processing unit 160 as an image signal Din. From the image signal Din, the signal processing circuit 51 generates an image signal synchronized with the scanner operation of the X scanner unit 55, according to the characteristics of the laser light, such as the wavelength. In the generated image signal, the signal processing circuit 51 converts the image signal for one line corresponding to one scanner operation into a continuous signal that outputs laser light continuously over time. The signal processing circuit 51 outputs the projected image signal thus generated to the laser drive circuit 52 of the drawing unit 150. The projected image signal is a signal that outputs one line of laser light continuously over time to each light source 53A, 53B, 53C, and is not a signal that outputs one line of laser light intermittently.

[0105] The laser driving circuit 52 drives each of the light sources 53A, 53B, and 53C of the light source unit 53 according to the projection image signal corresponding to each wavelength. At this time, the laser driving circuit 52 emits laser light from at least one of the light sources 53A, 53B, and 53C and scans it on the recording medium 10.

[0106] For example, to colorize the recording layer 13, a laser beam La with an emission wavelength λ1 is irradiated onto the recording layer 13 with an energy sufficient to reach the color-developing temperature. This causes the photothermal converter contained in the recording layer 13 to generate heat, and a color reaction occurs between the color-developing compound and the symmetric / dechromizing agent, resulting in the irradiated area developing a color, for example, magenta. Similarly, to colorize the recording layer 15, a laser beam Lb with an emission wavelength λ2 is irradiated onto the recording layer 15 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, cyan. To color the recording layer 17, a laser beam Lc with an emission wavelength λ3 is irradiated onto the recording layer 17 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, yellow. In this way, by irradiating any part with laser light of the corresponding wavelength, it becomes possible to record patterns, etc. (for example, full-color patterns, etc.).

[0107] The mechanism, consisting of an X-scanner drive circuit 54, an X-scanner unit 55, a Y-stage drive circuit 56, and a Y-stage 57, functions as a scanning unit that irradiates the surface of the recording medium 10 with laser light Lm generated by the light source unit 53. Preferably, the size and shape of the irradiation spot of the laser light Lm are such that the high-temperature region generated on the recording layer 13 and its periphery by the laser light La contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm. Furthermore, preferably, the size and shape of the irradiation spot of the laser light Lm are such that the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 17 and its periphery by the laser light Lc contained in the laser light Lm.

[0108] Next, we will describe the drawing marks formed on the recording medium 10 by the drawing system 100.

[0109] Figures 4(A), 5(A), and 6(A) show examples of the time-dependent change in the power of the laser beam Lm when the drawing unit 150 writes information to the recording medium 10. Figure 4(B) shows an example of a drawing trace when drawing with the power shown in Figure 4(A). Figure 5(B) shows an example of a drawing trace when drawing with the power shown in Figure 5(A). Figure 6(B) shows an example of a drawing trace when drawing with the power shown in Figure 6(A). Figures 4(A), 5(A), and 6(A) show examples of the light intensity of the laser beam Lm output in a single scanner operation. Figures 4(B), 5(B), and 6(B) show examples of drawing traces generated by a single scanner operation.

[0110] When the laser beam Lm is output at a constant high intensity, for example as shown in Figure 4(A), a band-shaped drawing mark of equal width is formed, for example as shown in Figure 4(B). When the laser beam Lm is output with gradually increasing intensity, for example as shown in Figure 5(A), a band-shaped drawing mark with gradually widening width is formed, for example as shown in Figure 5(B). When the laser beam Lm is output with increasing and decreasing intensity, for example as shown in Figure 6(A), a band-shaped drawing mark with widening and narrowing width is formed, for example as shown in Figure 6(B). Thus, the line width of the band-shaped drawing marks formed on the recording medium 10 by the drawing system 100 is corresponding to the gradation value of each color at each drawing coordinate of the leuco image data. Therefore, the image drawn on the recording medium 10 by the drawing system 100 forms stripes of irregular width.

[0111] A striped pattern typically refers to a pattern composed of multiple lines that extend continuously in a predetermined direction (a first direction) and are arranged side by side with predetermined gaps in a direction perpendicular to the first direction (a second direction). Note that each line of the striped pattern may have varying shades in the first direction. Furthermore, each line of the striped pattern may be composed of multiple minute lines with an aspect ratio greater than 1 (e.g., 2 or more). "Aspect ratio greater than 1" means that when the first direction is considered vertical and the second direction horizontal, (length in the first direction / length in the second direction) is greater than 1. In other words, a striped pattern does not include periodic patterns (dot patterns) consisting of multiple dots with nearly equal aspect ratios. In a striped pattern, the pitch in the first direction does not match the pitch visible in the second direction and is so small that it is difficult for humans to perceive, for example, on a size of a few micrometers.

[0112] Figure 7 shows an example of a drawing 20 formed by irradiating the recording medium 10 with laser light Lm. An image 20A formed by irradiation with laser light Lm is visible on the surface of the drawing 20. The image 20A is formed by continuous irradiation of the recording layers 13, 15, and 17 of the recording medium 10 with laser light Lm in the scanning direction, and is formed at a predetermined depth from the surface of the recording medium 10.

[0113] Figure 8 shows an example of image data 21 obtained by imaging the drawing object 20 (image 20A). In Figure 8, only a portion of image 20A (near the teardrop) of the image data 21 is shown in magnified view. The image data 21 contains irregularly sized stripe patterns 21a extending in the X direction, formed by irradiation with laser light Lm. Therefore, image 20A of the drawing object 20 contains irregularly sized stripe patterns 21a extending in the X direction, formed by irradiation with laser light Lm. In other words, irregularly sized stripe patterns 21a extending in the X direction are drawn on the recording layers 13, 15, and 17 of the recording medium 10 as drawing marks caused by continuous irradiation of laser light Lm on the surface of the recording medium 10 in the scanning direction. At this time, the stripe patterns 21a are formed by the superposition of the colored portions of the recording layers 13, 15, and 17.

[0114] Furthermore, if image 20A is an image containing a person's face, the X direction (the direction in which the striped pattern 21a extends) may be parallel to, for example, the line segment connecting the two eyes included in the image. Also, if image 20A is an image containing a person's face, the Y direction (the direction perpendicular to the direction in which the striped pattern 21a extends) may be perpendicular to, for example, the line segment connecting the two eyes included in the image. In this case, the recording medium 10 may be rectangular in plan view, or it may be a shape different from a rectangle in plan view (for example, a polygon, a circle, an ellipse, etc.).

[0115] Image data 21 is obtained, for example, by imaging using ring illumination. When image data is acquired using general illumination (e.g., simultaneous radiation), it becomes difficult to read the striped pattern 21a contained in image 20A from the image data due to light reflection on the surface of the recording medium 10 (protective layer 18). On the other hand, when ring illumination is used, the effect of light reflection on the surface of the recording medium 10 (protective layer 18) can be reduced, making it relatively easy to read the striped pattern 21a contained in image 20A from the image data.

[0116] Figure 9 shows an example of the spatial frequency spectrum of image data 21. In Figure 9, the spatial frequency spectrum of image data 21 in the X direction and the spatial frequency spectrum of image data 21 in the Y direction are superimposed on each other. The spatial frequency spectrum of image data 21 in the X direction has one large peak Px. On the other hand, the spatial frequency spectrum of image data 21 in the Y direction has a periodic peak Py that is not present in the spatial frequency spectrum of image data 21 in the X direction. Therefore, in the spatial frequency spectrum of image data 21, the Y direction profile, which is orthogonal to the X direction, has a periodic peak Py that is not present in the X direction profile, and the striped pattern 21a is drawn on the recording layers 13, 15, and 17 of the recording medium 10 in this manner.

[0117] Figure 10(A) shows an example of a measurement area specified in image data 21. In Figure 10(A), the measurement areas are shown as the vicinity of the tear duct (measurement area a), the vicinity of the cheek boundary (measurement area b), the background without a person (measurement area c), the vicinity of the outer corner of the eye (measurement area d), and the vicinity of the edge of the lip (measurement area e). Figure 10(B) shows an example of the peak ratio in each measurement area. The peak ratio refers to the intensity ratio at the position of the peak Py when the spatial frequency spectrum in the X direction and the spatial frequency spectrum in the Y direction of the image data 21 are superimposed on each other.

[0118] From Figure 10(B), it can be said that the striped pattern 21a is drawn on the recording layers 13, 15, and 17 of the recording medium 10 in a manner that satisfies the above intensity ratio of the following equation. S2 / S1 ≥ 1.2 S1: Intensity at the peak Py location of the X-direction profile. S2: Intensity at the peak Py location of the profile in the Y direction. S2 / S1: Above intensity ratio

[0119] The drawing unit 150 is capable of drawing an image 20A including the striped pattern 21a on the recording layers 13, 15, and 17 of the recording medium 10, so as to obtain the characteristics described above.

[0120] Next, an example of a method for forming a drawn object 20 using the drawing system 100 will be described. First, the user places an unprocessed (undrawn) recording medium 10 on the Y stage 57. Next, the user instructs the drawing system 100 to draw on the recording medium 10. The drawing system 100 then continuously irradiates the recording medium 10 with laser light Lm, forming irregular stripe patterns extending in the X direction as drawing marks on multiple thermal recording layers (recording layers 13, 15, 17). At this time, the drawing system 100 temporarily stops irradiating the laser light Lm each time one line of laser light Lm is completed, and moves the Y stage 57 by a predetermined amount in the Y direction so that the laser light Lm can be irradiated to the next line. Once the movement of the Y stage 57 is complete, the drawing system 100 irradiates the recording medium 10 with laser light Lm again.

[0121] The drawing system 100, for example, in the drawing process described above, draws the striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17) such that, in the spatial frequency spectrum of the image data 21 obtained by imaging with ring illumination, there is a periodic peak Py in the Y-direction spatial frequency profile that is not present in the X-direction spatial frequency profile. The drawing system 100, for example, draws the striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17) such that, when the X-direction spatial frequency profile and the Y-direction spatial frequency profile are superimposed on each other, the intensity ratio at the position of the peak Py satisfies the above equation (S2 / S1≧1.2). The drawing system 100 draws a striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17) such that, for example, the X direction is parallel to one edge of the recording medium 10 and the Y direction is parallel to another edge of the recording medium 10 that is perpendicular to the aforementioned edge. In this way, the drawn object 20 is formed.

[0122] [effect] Next, we will explain the effects of the drawing system 100.

[0123] As an alternative display medium to printed materials, recording media that reversibly record and erase information using heat, so-called reversible thermal recording media, have been developed. In a reversible thermal recording media, for example, multiple reversible thermal recording layers with different photothermal conversion wavelengths are stacked with an insulating layer in between. By pulsed laser light of a predetermined wavelength onto the reversible thermal recording media, heat is selectively generated in a specific reversible thermal recording layer, and information is recorded or erased by the action of the generated heat, causing color development or decolorization (see, for example, Patent Document 1).

[0124] Incidentally, Patent Document 1 states that in order to draw on a reversible thermal recording medium with higher resolution, it is necessary to reduce the irradiation area per pixel and irradiate with laser light at a higher energy density. On the other hand, semiconductor lasers have power limitations. Therefore, a problem may arise in which the desired image quality cannot be obtained due to insufficient laser power.

[0125] On the other hand, in this embodiment, irregular stripe patterns 21a extending in the X direction are drawn on the recording layers 13, 15, and 17 as drawing marks by continuous irradiation of laser light Lm on the surface of the recording medium 10 in the scanning direction. As a result, high resolution is obtained in the Y direction, which is perpendicular to the direction in which the stripe patterns 21a extend. On the other hand, in the X direction, which is parallel to the direction in which the stripe patterns 21a extend, the resolution is lower than in the Y direction. However, since drawing using continuous irradiation of laser light Lm can perform stripe-like drawing using heat transfer (drawing with continuous power control), it is possible to obtain the desired image quality with lower power compared to dot-like drawing using pulsed irradiation of laser light (drawing with intermittent power control). Therefore, high image quality can be achieved with low power.

[0126] Furthermore, in this embodiment, in the spatial frequency spectrum of the image data 21, a periodic peak Py exists in the Y-direction profile orthogonal to the X-direction, but not in the X-direction profile, and the striped pattern 21a is drawn on the recording layers 13, 15, and 17 in this manner. Here, the intensity ratio at the position of the peak Py when the X-direction profile and the Y-direction profile are superimposed on each other satisfies S2 / S1 ≥ 1.2. As a result, high resolution is obtained in the Y-direction orthogonal to the extension direction of the striped pattern 21a. On the other hand, in the X-direction parallel to the extension direction of the striped pattern 21a, the resolution is lower than in the Y-direction. However, since drawing using continuous irradiation of laser light Lm can perform striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed irradiation of laser light. Therefore, high image quality can be achieved with low power.

[0127] In this embodiment, the recording medium 10 is continuously irradiated with laser light Lm in the scanning direction, and a drawing 20 is formed on the recording layers 13, 15, and 17 by forming irregularly sized striped patterns 21a extending in the X direction as drawing marks. This results in high resolution in the Y direction, which is perpendicular to the direction of extension of the striped patterns 21a. On the other hand, the resolution in the X direction, which is parallel to the direction of extension of the striped patterns 21a, is lower than in the Y direction. However, since drawing using continuous irradiation of laser light Lm can perform striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed irradiation of laser light. Therefore, high image quality can be achieved with low power.

[0128] Furthermore, in this embodiment, during the drawing process, a striped pattern 21a is drawn on the recording layers 13, 15, and 17 such that, in the spatial frequency spectrum of the image data 21, a periodic peak Py exists in the Y-direction profile orthogonal to the X-direction, but is not present in the X-direction profile. Here, the striped pattern 21a is drawn on the recording layers 13, 15, and 17 such that the intensity ratio at the position of the peak Py, when the X-direction profile and the Y-direction profile are superimposed on each other, satisfies S2 / S1 ≥ 1.2. As a result, high resolution is obtained in the Y-direction, which is orthogonal to the extension direction of the striped pattern 21a. On the other hand, the resolution in the X-direction, which is parallel to the extension direction of the striped pattern 21a, is lower than in the Y-direction. However, since drawing using continuous irradiation of laser light Lm allows for striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed irradiation of laser light. Therefore, high image quality can be achieved with low power.

[0129] <2. Variant> The following describes a modified version of the drawing system 100 according to one embodiment of the present disclosure.

[0130] [Differentiation A] Figure 11 shows a modified example of the schematic configuration of the drawing system 100 according to the above embodiment. In the above embodiment, the recording medium 10 is a sheet-like or plate-like recording medium that is rectangular in plan view, with the X direction being parallel to one edge of the recording medium 10 and the Y direction being parallel to another edge of the recording medium 10 that is perpendicular to the aforementioned edge. However, as shown in Figure 11, for example, the X and Y directions may be in directions that diagonally intersect all the edges of the recording medium 10. In this case, the Y stage 57 is rotated by a predetermined angle θ (0 < θ < 90°) in the XY plane compared to the arrangement in the above embodiment. Then, the drawing system 100 draws a striped pattern 21a on a plurality of thermal recording layers (recording layers 13, 15, 17) such that, for example, the X and Y directions are in directions that diagonally intersect all the edges of the recording medium 10.

[0131] Figure 12(A) shows an example of image data 21 of a drawing 20 formed by irradiating the recording medium 10 with laser light Lm using the drawing system 100 of Figure 11. Figure 12(B) shows an example of the spatial frequency spectrum of the image data. In Figure 12(A), the horizontal axis represents the spatial frequency in the X direction, and the vertical axis represents the spatial frequency in the Y direction. Also, in Figure 12(A), the angle θ is 45°, and the striped pattern 21a extends in a direction that intersects all edges of the recording medium 10 at a 45° angle. In Figure 12(B), multiple bright spots are arranged in a line in a direction perpendicular to the extension direction of the striped pattern 21a. In Figure 12(B), each bright spot corresponds to the peak Py mentioned above.

[0132] In this modified example, similar to the above embodiment, irregularly sized striped patterns 21a extending in the X direction are drawn on the recording layers 13, 15, and 17 as drawing marks by continuous irradiation of laser light Lm onto the surface of the recording medium 10. This provides high resolution in the Y direction, which is perpendicular to the direction of extension of the striped patterns 21a. On the other hand, in the X direction, which is parallel to the direction of extension of the striped patterns 21a, the resolution is lower than in the Y direction. However, since drawing using continuous irradiation of laser light Lm allows for striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed laser irradiation.

[0133] Furthermore, in this modified example, similar to the above embodiment, the recording medium 10 is continuously irradiated with laser light Lm in the scanning direction, and the drawn object 20 is formed on the recording layers 13, 15, and 17 by forming irregularly sized striped patterns 21a extending in the X direction as drawing marks. As a result, high resolution is obtained in the Y direction, which is perpendicular to the direction of extension of the striped patterns 21a. On the other hand, in the X direction, which is parallel to the direction of extension of the striped patterns 21a, the resolution is lower than in the Y direction. However, since drawing using continuous irradiation of laser light Lm can perform striped drawing using heat transfer, it is possible to obtain the desired image quality with lower power compared to dot-shaped drawing using pulsed irradiation of laser light. Therefore, high image quality can be achieved with low power.

[0134] [Variation B] Figures 13 and 14 show a modified example of the schematic configuration of the drawing unit 150 according to the above embodiment and modified example A. In the above embodiment, raster scanning was achieved by scanning the laser beam Lm in the X-axis direction with the X scanner unit 55 and moving the Y stage 57 in the Y-axis direction. However, in the above embodiment and modified example A, raster scanning may be achieved by using an XY scanner drive circuit 54A, an XY scanner unit 55A and a fixed stage 57A instead of the X scanner drive circuit 54, X scanner unit 55, Y stage drive circuit 56 and Y stage 57, for example, as shown in Figures 13 and 14. In addition, in the drawing unit 150 shown in Figures 13 and 14, a drive circuit for moving the fixed stage 57A may be provided, and raster scanning may be achieved by moving the fixed stage 57A.

[0135] The XY scanner drive circuit 54A drives the XY scanner unit 55A based on a control signal input from, for example, the signal processing circuit 51. Furthermore, if, for example, the XY scanner drive circuit 54A receives a signal from the XY scanner unit 55A regarding the illumination angle of a two-axis scanner 55c (described later), it drives the XY scanner unit 55A to achieve a desired illumination angle based on that signal.

[0136] The XY scanner unit 55A, for example, scans the laser light Lm incident from the light source unit 53 on the surface of the recording medium 10 in the X-axis direction and moves the scan line in the Y-axis direction by a predetermined step width. The XY scanner unit 55A includes, for example, a two-axis scanner 55c and an fθ lens 55b. The two-axis scanner 55c is a galvanometer mirror that scans the laser light Lm incident from the light source unit 53 on the surface of the recording medium 10 in the X-axis direction based on a drive signal input from the XY scanner drive circuit 54A and moves the scan line in the Y-axis direction by a predetermined step width. The fθ lens 55b converts the constant velocity rotational motion of the two-axis scanner 55c into the constant velocity linear motion of a spot moving on the focal plane (the surface of the recording medium 10). The fixed stage 57A is simply a stand that supports the recording medium 10.

[0137] In this modified example, only the method of realizing raster scanning differs from the above embodiment; however, the fact that the striped pattern 21a is drawn on the recording layers 13, 15, and 17 is the same as in the above embodiment. Therefore, high image quality can be achieved with low power even in this modified example.

[0138] [Differentiation C] Figure 15 shows an example of a perspective view of a laminate 30 equipped with one or more recording media 10 according to the above embodiment and modified examples A and B. Figure 16 shows an example of a cross-sectional view of the laminate 30 in Figure 15 along line AA.

[0139] The laminate 30 can be applied to, for example, medical supplies, automotive parts, automobiles, toys, food products, cosmetics, clothing, documents (e.g., passports), exterior components, or casings of electronic devices. Specific examples of exterior components include, for example, interior or exterior walls of buildings, or the exteriors of furniture such as desks. Specific examples of electronic devices include personal computers (hereinafter referred to as "PCs"), mobile devices, mobile phones (e.g., smartphones), tablet computers, display devices, cameras, audio equipment, game consoles, industrial equipment, medical equipment, robots, or wearable devices. Specific examples of wearable devices include watches, bags, clothing, hats, glasses, or shoes.

[0140] The laminate 30 comprises a base material 31, an adhesive layer 32, a spacer layer 33, an adhesive layer 34, an overlay layer 35, and one or more recording media 10. The laminate 30 may be a card such as a security card, a financial settlement card, an ID card, or a personal transaction card (hereinafter referred to as "security card, etc."). Examples of financial settlement cards include credit cards and cash cards. Examples of ID cards include driver's licenses, employee IDs, membership cards, and student IDs. Examples of personal transaction cards include prepaid cards and point cards.

[0141] The base material 31 is a support that supports the recording medium 10 and the spacer layer 33. The base material 31 may have a color such as white. The base material 31 may have a design, picture, photograph, character, or a combination of two or more of these (hereinafter referred to as "design, etc.") printed on one of its main surfaces on the side where the spacer layer 33 and the recording medium 10 are provided.

[0142] The base material 31 includes, for example, plastic. The base material 31 may optionally contain at least one selected from the group consisting of colorants, antistatic agents, flame retardants, and surface modifiers. A reflective layer (not shown) may be provided on at least one main surface of the base material 31, or the base material 31 itself may also function as a reflective layer.

[0143] The plastic used in the base material 31 includes, for example, at least one selected from the group consisting of ester resins, amide resins, olefin resins, vinyl resins, acrylic resins, imide resins, styrene resins, and engineering plastics. If the base material 31 contains two or more resins, these two or more resins may be mixed, copolymerized, or laminated.

[0144] The above ester resin includes, for example, at least one selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene terephthalate-isophthalate copolymer, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. The above amide resin includes, for example, at least one selected from the group consisting of nylon 6, nylon 66, and nylon 610. The above olefin resin includes, for example, at least one selected from the group consisting of polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP). The above vinyl resin includes, for example, polyvinyl chloride (PVC).

[0145] The above acrylic resin includes, for example, at least one selected from the group consisting of polyacrylate, polymethacrylate, and polymethyl methacrylate (PMMA). The above imide resin includes, for example, at least one selected from the group consisting of polyimide (PI), polyamideimide (PAI), and polyetherimide (PEI). The above styrene resin includes, for example, at least one selected from the group consisting of polystyrene (PS), high-impact polystyrene, acrylonitrile-styrene resin (AS resin), and acrylonitrile-butadiene-styrene resin (ABS resin). The above-mentioned engineering plastics include, for example, at least one selected from the group consisting of polycarbonate (PC), polyarylate (PAR), polysulfone (PSF), polyethersulfone (PES), polyphenylene ether (PPE), polyphenylene sulfide (PPS), polyetherketone (PEK), polyether-etherketone (PEEK), polyphenylene oxide (PPO), and polyethersulfite.

[0146] The spacer layer 33 is provided on one main surface of the base material 31, with an adhesive layer 32 sandwiched between the base material 31 and the spacer layer 33. The spacer layer 33 has a housing portion 33A for housing the recording medium 10. The housing portion 33A is provided in a part of the plane of the spacer layer 33. The housing portion 33A may be a through hole that penetrates in the thickness direction of the spacer layer 33. The spacer layer 33 is intended to suppress the step difference formed by the recording medium 10 when the recording medium 10 is sandwiched between the base material 31 and the overlay layer 35. The spacer layer 33 has approximately the same thickness as the recording medium 10 and covers the area of ​​one main surface of the base material 31 other than the area where the recording medium 10 is provided.

[0147] The spacer layer 33 is in the form of a film. The spacer layer 33 may be transparent. The spacer layer 33 contains plastic. Examples of plastics used for the spacer layer 33 include the same materials as those used for the base material 31.

[0148] The overlay layer 35 is provided on the spacer layer 33 and the recording medium 10, and covers the spacer layer 33 and the recording medium 10. An adhesive layer 34 is sandwiched between the spacer layer 33 and the recording medium 10 and the overlay layer 35. The overlay layer 35 protects the internal components of the laminate 30 (i.e., the recording medium 10 and the spacer layer 33) and maintains the mechanical reliability of the laminate 30.

[0149] The overlay layer 35 is in the form of a film. The overlay layer 35 is transparent. The overlay layer 35 contains plastic. Examples of plastic used in the overlay layer 35 include the same materials as those used for the base material 31. A design or pattern may be printed on at least one main surface of the overlay layer 35.

[0150] Adhesive layer 32 is provided between the base material 31 and the spacer layer 33, bonding the base material 31 and the spacer layer 33 together. Adhesive layer 34 is provided between the spacer layer 33 and the overlay layer 35, bonding the spacer layer 33 and the overlay layer 35 together. Adhesive layers 32 and 34 are transparent. Adhesive layers 32 and 34 contain a thermal adhesive. The thermal adhesive used in adhesive layers 32 and 34 contains a thermosetting resin. The thermosetting resin used in adhesive layers 32 and 34 includes, for example, at least one selected from the group consisting of epoxy resins and urethane resins. The curing temperature of the thermal adhesive is preferably in the temperature range of 100°C to 120°C from the viewpoint of reducing damage to the recording medium 10.

[0151] The following describes an example of a method for manufacturing the laminate 30.

[0152] First, a thermosetting resin is applied to one main surface of the base material 31 as a thermal adhesive to form an adhesive layer 32. Next, a spacer layer 33 is placed on the adhesive layer 32, and then the recording medium 10 is fitted into the housing portion 33A of the spacer layer 33. Alternatively, a spacer layer 33 with the recording medium 10 already fitted into the housing portion 33A may be placed on the adhesive layer 32. The adhesive layer 32 may also be formed by applying a thermosetting resin to a spacer layer 33 with the recording medium 10 already fitted into the housing portion 33A, and then placing the spacer layer 33 on the main surface of the base material 31 with the coating film in between. Alternatively, the adhesive layer 32 may be formed by bonding a sheet, which has been formed in advance by applying a thermosetting resin to a separator, to the main surface of the base material 31 or to a spacer layer 33 with the recording medium 10 already fitted into the housing portion 33A by means of thermal lamination or the like.

[0153] Next, a thermosetting resin is applied to the spacer layer 33 as a thermal adhesive to form an adhesive layer 34, and then an overlay layer 35 is placed on the adhesive layer 34. Next, the resulting laminate 30 is sandwiched between metal plates and the adhesive layer 34 is heat-cured by heating and applying pressure. The temperature applied to the laminate 30 during heat curing is preferably 100°C to 120°C from the viewpoint of reducing damage to the recording medium 10. This yields the desired laminate 30. The adhesive layer 34 may also be formed by applying a thermosetting resin to the overlay layer 35 and then placing the overlay layer 35 on the spacer layer 33 with the coating film in between. Alternatively, the adhesive layer 34 may be formed by bonding a sheet, which has been formed in advance by applying a thermosetting resin to a separator, to the overlay layer 35 or the spacer layer 33 by means of thermal lamination or the like.

[0154] In this modified example, the recording medium 10 may be provided across the entire surface of the laminate 30 in a plan view. In this case, the spacer layer 33 is omitted in the laminate 30.

[0155] Furthermore, in this modified example, the adhesive layers 32 and 34 may be omitted, and the base material 31 and the spacer layer 33 may be bonded to each other by fusion, and the spacer layer 33 and the overlay layer 35 may be bonded to each other by fusion.

[0156] In this case, it is preferable that the base material 31, spacer layer 33, and overlay layer 35 contain a thermoplastic resin as the plastic. By including a thermoplastic resin in the base material 31, spacer layer 33, and overlay layer 35, the interlayer adhesion strength due to fusion can be strengthened. From the viewpoint of reducing damage to the recording medium 10, it is preferable that the thermoplastic resin is capable of heat-sealing the interlayers of the laminate 30 in a temperature range of 130°C to 200°C.

[0157] The base material 31, spacer layer 33, and overlay layer 35 may contain the same type of thermoplastic resin, or they may not contain the same type of thermoplastic resin. If the base material 31, spacer layer 33, and overlay layer 35 do not contain the same type of thermoplastic resin, one of the base material 31, spacer layer 33, and overlay layer 35 may contain a different type of thermoplastic resin than the other two layers. If the base material 31, spacer layer 33, and overlay layer 35 do not contain the same type of thermoplastic resin, each of the base material 31, spacer layer 33, and overlay layer 35 may contain different types of thermoplastic resin.

[0158] When the base material 31, spacer layer 33, and overlay layer 35 contain the same type of thermoplastic resin, it is preferable that the base material 31, spacer layer 33, and overlay layer 35 contain at least one selected from the group consisting of semicrystalline thermoplastic resins and amorphous thermoplastic resins, from the viewpoint of improving interlayer adhesion strength by fusion.

[0159] The semi-crystalline thermoplastic resin includes, for example, at least one selected from the group consisting of polypropylene (PP), polyethylene (PE), polyacetal (POM), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), and polyether ether ketone (PEEK).

[0160] The amorphous thermoplastic resin includes, for example, at least one selected from the group consisting of ABS resin, polycarbonate (PC), polymer alloy of ABS resin and PC (hereinafter referred to as "ABS / PC polymer alloy"), AS resin, polystyrene (PS), polymethyl methacrylate (PMMA), polyphenylene oxide (PPO), polysulfone (PSU), polyvinyl chloride (PVC), polyetherimide (PEI), and polyethersulfone (PES).

[0161] If the base material 33, spacer layer 33, and overlay layer 35 do not contain the same type of thermoplastic resin, it is preferable that the base material 31, spacer layer 33, and overlay layer 35 contain an amorphous thermoplastic resin from the viewpoint of improving interlayer adhesion strength through fusion.

[0162] The following combinations of amorphous thermoplastic resins are preferred for the two adjacent layers of the laminate 30. If one of the two adjacent layers of the laminate 30 contains ABS resin, it is preferable that the other layer contains at least one selected from the group consisting of ABS / PC polymer alloy, polycarbonate (PC), AS resin, polystyrene (PS), polymethyl methacrylate (PMMA), and polyvinyl chloride (PVC).

[0163] If one of two adjacent layers of the laminate 30 contains an ABS / PC polymer alloy, it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, polycarbonate (PC), and polymethyl methacrylate (PMMA).

[0164] If one of two adjacent layers of the laminate 30 contains AS resin, it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, polystyrene (PS), polymethyl methacrylate (PMMA), and polyphenylene oxide (PPO).

[0165] If one of two adjacent layers of the laminate 30 contains polymethyl methacrylate (PMMA), it is preferable that the other layer contains at least one selected from the group consisting of ABS resin, ABS / PC polymer alloy, AS resin, and polyphenylene oxide (PPO). If one of two adjacent layers of the laminate 30 contains polyphenylene oxide (PPO), it is preferable that the other layer contains at least one selected from the group consisting of polycarbonate (PC), AS resin, polystyrene (PS), and polymethyl methacrylate (PMMA).

[0166] If one of two adjacent layers of the laminate 30 contains polysulfone (PSU), it is preferable that the other layer contains polycarbonate (PC). If one of two adjacent layers of the laminate 30 contains polyvinyl chloride (PVC), it is preferable that the other layer contains ABS resin.

[0167] Next, an example of a method for manufacturing the laminate 30 according to this modified example will be described. First, a recording medium 10 is placed on one main surface of the base material 31. Next, an overlay layer 35 is placed on the recording medium 10. Then, the laminate consisting of the base material 31, the recording medium 10, and the overlay layer 35 is sandwiched between metal plates and heated and pressed to heat-seal the base material 31 and the recording medium 10, and also heat-seal the recording medium 10 and the overlay layer 35. The temperature applied to the laminate during heat sealing is preferably 130°C to 200°C from the viewpoint of reducing damage to the recording medium 10 and achieving sufficient fusion strength. This yields the laminate 30 according to this modified example.

[0168] In this modified example, instead of the housing portion 13A, a bottomed recess that is recessed in the thickness direction of the spacer layer 33 may be provided. In this case, the recess may be provided on the main surface of the spacer layer 33 that faces the overlay layer 35, or on the main surface that faces the base material 31.

[0169] [Differentiation D] In the modified example C described above, the laminate 30 may include, for example, a laser marking layer 36 with a different color and light absorption wavelength band in a different colored state than the recording layers 13, 15, and 17, as shown in Figure 17. The laser marking layer 36 corresponds to a specific example of the "second thermal recording layer" according to one embodiment of this disclosure. The laser marking layer 36 is configured to change its colored state in response to external stimuli such as laser light or heat. The laser marking layer 36 is composed of a material that can produce black or dark colors in response to external stimuli such as laser light or heat. The laser marking layer 36 uses a different recording method (a recording method with a different coloring principle) than the recording layers 13, 15, and 17.

[0170] The laser marking layer 36 may be a known laser marking sheet. The laser marking layer 36 is a thermal recording layer configured to be laser marked by, for example, at least one of the following methods (1) to (5). (1) A method of producing color by foaming a resin material. (2) A method of adding an additive that absorbs laser light to a resin material and 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 to produce color. (4) A method that utilizes the change in surface condition by etching the surface of the resin layer with laser irradiation. (5) A method of marking by irradiating a resin material colored black or a dark color with laser light, thereby sublimating (decomposing) the coloring agent (carbon black) and decolorizing it (exposing the base color of the resin material).

[0171] The laser marking layer 36 includes, for example, a photothermal conversion agent and a resin material. The resin material used in the laser marking layer 36 includes, for example, a polycarbonate-based resin. The photothermal conversion agent used in the laser marking layer 36 is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. It is preferable to select a photothermal conversion agent used in the laser marking layer 36 that has a narrow light absorption band in the near-infrared region and has a light absorption wavelength band that does not overlap with the light absorption bands of the recording layers 13, 15, and 17. The photothermal conversion agent used in the laser marking layer 36 includes, for example, carbon.

[0172] The laser marking layer 36 is positioned in the laminate 30 at a location that faces the recording medium 10 in the stacking direction of each layer. The laser marking layer 36 is positioned between the substrate 31, the spacer layer 33, and the recording medium 10, for example, as shown in Figure 17. In this case, the laser marking layer 36 is bonded to the substrate 31 via an adhesive layer 37, and further bonded to the spacer layer 33 and the recording medium 10 via an adhesive layer 32, for example, as shown in Figure 17.

[0173] In this modified example, the laminate 30 may, for example, include a laser marking layer 38 with a different color and light absorption wavelength band in a different color state than the recording layers 13, 15, and 17, instead of the laser marking layer 36, as shown in Figure 18.

[0174] The laser marking layer 38 is configured to change its color state in response to external stimuli such as laser light or heat. For example, the laser marking layer 38 is made of a material that can produce black or dark colors in response to external stimuli such as laser light or heat. The laser marking layer 38 uses a different recording method (a recording method with a different color generation principle) than the recording layers 13, 15, and 17.

[0175] The laser marking layer 38 may be a known laser marking sheet. The laser marking layer 38 is configured to be laser marked by, for example, at least one of the methods (1) to (5) described above.

[0176] The laser marking layer 38 includes, for example, a photothermal conversion agent and a resin material. The resin material used in the laser marking layer 38 includes, for example, a polycarbonate-based resin. The photothermal conversion agent used in the laser marking layer 38 is, for example, one that absorbs light in a predetermined wavelength range in the near-infrared region and generates heat. It is preferable to select a photothermal conversion agent used in the laser marking layer 38 that has a narrow light absorption band in the near-infrared region and has a light absorption wavelength band that does not overlap with the light absorption bands of the recording layers 13, 15, and 17. The photothermal conversion agent used in the laser marking layer 38 includes, for example, carbon.

[0177] The laser marking layer 38 is positioned in the laminate 30 at a location that faces the recording medium 10 in the stacking direction of each layer. The laser marking layer 38 is positioned between the spacer layer 33 and the recording medium 10 and the overlay layer 35, for example, as shown in Figure 18. In this case, the laser marking layer 38 is bonded to the overlay layer 35 via an adhesive layer 34, and further bonded to the spacer layer 33 and the recording medium 10 via an adhesive layer 39, for example, as shown in Figure 18.

[0178] In this modified example, the laser marking layer 36 may be arranged within the housing section 33A, for example, as shown in Figure 19. The laser marking layer 36 is arranged between the substrate 31 and the recording medium 10 within the housing section 33A. In this case, the laser marking layer 36 is bonded to the substrate 31 via an adhesive layer 32, for example, as shown in Figure 19, and further bonded to the recording medium 10 via an adhesive layer 37.

[0179] In this modified example, the laser marking layers 36 and 38 may be arranged only in locations within the laminate 30 that are not facing the recording medium 10 in the stacking direction of each layer. In this case, the markings on the recording medium 10 and the markings on the laser marking layers 36 and 38 can be seen in the laminate 30 without overlapping.

[0180] Furthermore, in Figure 17, the adhesive layers 32 and 37 may be omitted, and the substrate 31 and the laser marking layer 36 may be bonded to each other by fusion, and the laser marking layer 36, the spacer layer 33 and the recording medium 10 may be bonded to each other by fusion. Also, in Figure 17, the adhesive layer 34 may be omitted, and the spacer layer 33 and the recording medium 10 and the overlay layer 35 may be bonded to each other by fusion.

[0181] Furthermore, in Figure 18, the adhesive layer 32 may be omitted, and the substrate 31, the spacer layer 33, and the recording medium 10 may be bonded together by fusion. Also, in Figure 18, the adhesive layers 34 and 39 may be omitted, and the spacer layer 33, the recording medium 10, and the laser marking layer 38 may be bonded together by fusion, as well as the laser marking layer 38 and the overlay layer 35 may be bonded together by fusion.

[0182] Furthermore, in Figure 19, the adhesive layers 32 and 37 may be omitted, and the substrate 31, the laser marking layer 36, and the spacer layer 33 may be bonded to each other by fusion, as well as the laser marking layer 36 and the recording medium 10 may be bonded to each other by fusion. Also, in Figure 19, the adhesive layer 34 may be omitted, and the spacer layer 33 and the recording medium 10 and the overlay layer 35 may be bonded to each other by fusion.

[0183] Figure 20 shows a schematic configuration example of a drawing system 100 capable of performing laser drawing on laser marking layers 36 and 38. The drawing system 100 according to this modified example is capable of writing (drawing) and erasing information on a laminate 30 equipped with one or more recording media 10.

[0184] The drawing system 100 according to this modified example is, for example, the drawing system 100 according to the above embodiment, but with a drawing unit 250 instead of a drawing unit 150. The drawing unit 250 includes, for example, a signal processing circuit 251, a laser drive circuit 252, a light source unit 253, an X scanner drive circuit 254, an X scanner unit 255, a Y stage drive circuit 256, and a Y stage 257, as shown in Figure 21. The drawing unit 250 can perform drawing on the laminate 30 by controlling the output of the light source unit 253 based on a voltage value file (list of command voltage values) input from the information processing unit 160.

[0185] The signal processing circuit 251 is capable of acquiring a voltage value file (a list of command voltage values) input from the information processing unit 160 as an image signal Din. The signal processing circuit 251 is capable of generating a pixel signal Dout from the image signal Din, for example, according to the scanner operation of the X scanner unit 255. The pixel signal Dout causes the light source unit 253 (for example, each of the light sources 53A, 53B, 53C, 53D described later) to output laser light with power corresponding to the command voltage value. Together with the laser drive circuit 252, the signal processing circuit 251 is capable of controlling the peak value of the current applied to the light source unit 253 (for example, each of the light sources 53A, 53B, 53C, 53D) according to the pixel signal Dout.

[0186] The laser driving circuit 252 is capable of driving each of the light sources 53A, 53B, 53C, and 53D of the light source unit 253 according to the pixel signal Dout. The laser driving circuit 252 is capable of controlling the brightness (brightness / darkness) of the laser light in order to draw an image corresponding to the pixel signal Dout. The laser driving circuit 252 includes, for example, a driving circuit 52A for driving light source 53A, a driving circuit 52B for driving light source 53B, a driving circuit 52C for driving light source 53C, and a driving circuit 52D for driving light source 53D.

[0187] Light sources 53A, 53B, 53C, and 53D are capable of performing drawing on the laminate 30 by outputting laser light with power corresponding to the command voltage value to the laminate 30. Light sources 53A, 53B, 53C, and 53D are capable of emitting laser light in the near-infrared region. Light source 53A is, for example, a semiconductor laser that emits laser light La with an emission wavelength λ1. Light source 53B is, for example, a semiconductor laser that emits laser light Lb with an emission wavelength λ2. Light source 53C is, for example, a semiconductor laser that emits laser light Lc with an emission wavelength λ3. Light source 53D is, for example, an excimer laser that emits laser light Ld with an emission wavelength λ4 that can be recorded on the laser marking layers 36 and 38.

[0188] The light source unit 253 has multiple light sources (for example, four light sources 53A, 53B, 53C, 53D) with different emission wavelengths in the near-infrared region. Each light source (for example, each light source 53A, 53B, 53C, 53D) is capable of generating laser light that includes wavelengths corresponding to the optical absorption wavelength band of, for example, the photothermal conversion agent (described later) contained in the laminate 30. The light source unit 253 further has an optical system that combines multiple laser beams (for example, four laser beams La, Lb, Lc, Ld) emitted from the multiple light sources (for example, four light sources 53A, 53B, 53C, 53D). This optical system is capable of outputting a combined wave of multiple laser beams La, Lb, Lc, and Ld (laser beam Lm) to the X scanner unit 55, such that multiple irradiation spots Pa, Pb, Pc, and Pd generated on the laminate 30 by multiple laser beams La, Lb, Lc, and Ld overlap each other on the Y stage 57. In other words, the light source unit 253 is composed of a single optical system that includes the optical systems of light sources 53A, 53B, and 53C, which contain three-wavelength semiconductor lasers, and the optical system of light source 53D, which contains an excimer laser. The X-axis direction is perpendicular to the movement direction of the Y stage 57 (Y-axis direction) and parallel to the scanning direction of the 1-axis scanner 55a, which will be described later. The light source unit 253 has, for example, two reflective mirrors 53a and 53e and three dichroic mirrors 53b, 53c, and 53f as such an optical system.

[0189] The laser beams La and Lb emitted from the two light sources 53A and 53B are, for example, made nearly parallel light (collimated light) by a collimating lens. Then, for example, the laser beam La is reflected by the reflective mirror 53a and also by the dichroic mirror 53b, while the laser beam Lb is transmitted through the dichroic mirror 53b. As a result, the laser beam La and the laser beam Lb are combined. The combined light of the two laser beams La is transmitted through the dichroic mirror 53c.

[0190] Laser beams Lc and Ld emitted from light sources 53C and 53D are made into substantially parallel light (collimated light) by a collimator lens, for example. Thereafter, the laser beam Lc is reflected by, for example, a dichroic mirror 53f and then reflected by a dichroic mirror 53c. Accordingly, the multiplexed light transmitted through the dichroic mirror 53c and the laser beam Lc reflected by the dichroic mirror 53c are multiplexed. The laser beam Ld is reflected by, for example, a reflection mirror 53e, transmitted through the dichroic mirror 53f, and then reflected by the dichroic mirror 53c. Accordingly, the multiplexed light transmitted through the dichroic mirror 53c, the laser beam Lc reflected by the dichroic mirror 53c, and the laser beam Ld reflected by the dichroic mirror 53c are multiplexed. The light source unit 53 outputs, for example, the light (laser beam Lm) obtained by multiplexing through the above optical system to the X scanner unit 255.

[0191] The X scanner driving circuit 254 can drive the X scanner unit 255 based on a control signal input from the signal processing circuit 251, for example. Further, for example, when a signal about an irradiation angle of the uniaxial scanner 55a or the like is input from the X scanner unit 255 to the X scanner driving circuit 254, the X scanner driving circuit 254 drives the X scanner unit 255 to achieve a desired irradiation angle based on the signal.

[0192] The X scanner unit 255 can scan the laser beam Lm incident from the light source unit 253 in the X-axis direction on the surface of the laminate 30, for example. The X scanner unit 255 includes, for example, a uniaxial scanner 55a and an fθ lens 55b. The uniaxial scanner 55a is, for example, a galvanometer mirror that scans the laser beam Lm incident from the light source unit 253 in the X-axis direction on the surface of the laminate 30 based on a driving signal input from the X scanner driving circuit 254. The fθ lens 55b can convert the constant-velocity rotational motion by the uniaxial scanner 55a into the constant-velocity linear motion of a spot moving on a focal plane (the surface of the laminate 30).

[0193] The Y-stage drive circuit 256 can drive the Y-stage 257 based on a control signal input from, for example, the signal processing circuit 251. By displacing the Y-stage 257 in the Y-axis direction at a predetermined speed, the Y-stage 257 can move the laminate 30 placed on the Y-stage 257 in the Y-axis direction relative to the X-scanner unit 255 at a predetermined speed. The coordinated operation of the X-scanner unit 255 and the Y-stage 257 enables the laser beam Lm to raster scan the surface of the laminate 30.

[0194] Next, an example of writing information in the drawing system 100 according to this modified example will be described.

[0195] First, the user prepares an uncolored laminate 30 and places it on the Y stage 257. Next, the user transmits input image data described in the RGB color space to the drawing system 100 via the network from a terminal device. When the drawing system 100 receives the input image data via the network, it executes the following drawing process.

[0196] First, when the information processing unit 160 receives input image data via the communication unit 110, it converts the input image data, which is described in the RGB color space, into leuco image data described in the leuco color space and monochrome image data described in a black or dark color space. Next, the information processing unit 160 derives a voltage value file (list of command voltage values) based on the gradation values ​​of each color at each drawing coordinate of the leuco image data and monochrome image data obtained by the conversion. The information processing unit 160 then transmits the derived voltage value file (list of command voltage values) to the drawing unit 250.

[0197] The signal processing circuit 251 of the drawing unit 250 acquires a voltage value file (list of command voltage values) input from the information processing unit 160 as an image signal Din. From the image signal Din, the signal processing circuit 251 generates an image signal synchronized with the scanner operation of the X scanner unit 255, according to the characteristics of the laser light, such as the wavelength. In the generated image signal, the signal processing circuit 251 converts the image signal for one line corresponding to one scanner operation into a continuous signal that outputs laser light continuously over time. The signal processing circuit 251 outputs the projected image signal thus generated to the laser drive circuit 252 of the drawing unit 250. The projected image signal is a signal that outputs one line of laser light continuously over time to each light source 53A, 53B, 53C, 53D, and is not a signal that outputs one line of laser light intermittently.

[0198] The laser driving circuit 252 drives each of the light sources 53A, 53B, 53C, and 53D of the light source unit 253 according to the projection image signal corresponding to each wavelength. At this time, the laser driving circuit 252 emits laser light from at least one of the light sources 53A, 53B, 53C, and 53D and scans it on the laminate 30.

[0199] For example, to colorize the recording layer 13, a laser beam La with an emission wavelength λ1 is irradiated onto the recording layer 13 with an energy sufficient to reach the color-developing temperature. This causes the photothermal converter contained in the recording layer 13 to generate heat, and a color reaction occurs between the color-developing compound and the symmetric / dechromizing agent, resulting in the irradiated area developing a color, for example, magenta. Similarly, to colorize the recording layer 15, a laser beam Lb with an emission wavelength λ2 is irradiated onto the recording layer 15 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, cyan. To color the recording layer 17, a laser beam Lc with an emission wavelength λ3 is irradiated onto the recording layer 17 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, yellow. In this way, by irradiating any part with laser light of the corresponding wavelength, it becomes possible to record patterns, etc. (for example, full-color patterns, etc.).

[0200] Similarly, to color the laser marking layers 36 and 38, a laser beam Ld with an emission wavelength λ4 is irradiated onto the laser marking layers 36 and 38 with an energy sufficient to reach the coloring temperature, causing the irradiated area to develop a color such as black or a dark color. In this way, by irradiating any area with laser beam of the corresponding wavelength, it becomes possible to record patterns (for example, full-color patterns).

[0201] The mechanism, consisting of an X-scanner drive circuit 254, an X-scanner unit 255, a Y-stage drive circuit 256, and a Y-stage 257, functions as a scanning unit that irradiates the surface of the laminate 30 with laser light Lm generated by the light source unit 253. Preferably, the size and shape of the laser light Lm irradiation spot are such that the high-temperature region generated on the recording layer 13 and its periphery by the laser light La contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm. Furthermore, preferably, the size and shape of the laser light Lm irradiation spot are such that the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 17 and its periphery by the laser light Lc contained in the laser light Lm.

[0202] Furthermore, it is preferable that the size and shape of the laser beam Lm irradiation spot are such that the high-temperature region generated on the recording layer 17 and its surroundings by the laser beam Lc contained in the laser beam Lm does not overlap with the high-temperature region generated on the laser marking layer 38 and its surroundings by the laser beam Ld contained in the laser beam Lm. Furthermore, it is preferable that the size and shape of the laser beam Lm irradiation spot are such that the high-temperature region generated on the recording layer 13 and its surroundings by the laser beam La contained in the laser beam Lm does not overlap with the high-temperature region generated on the laser marking layer 36 and its surroundings by the laser beam Ld contained in the laser beam Lm.

[0203] Figure 22 shows an example of a drawing 40 formed by irradiating a laminate 30 comprising one or more recording media 10 with laser light Lm. Of the drawing 40, an image 20A formed by irradiation with laser light Lm is visible on the surface of the recording media 10. Image 20A is formed by continuous irradiation of the recording layers 13, 15, 17 and the laser marking layer 36 or laser marking layer 38 of the recording media 10 with laser light Lm in the scanning direction, and is formed at a predetermined depth from the surface of the recording media 10. Image 20A has the features described in Figures 8, 9, 10(A), and 10(B), for example.

[0204] Next, an example of a method for forming a drawn object 40 using the drawing system 100 will be described. First, the user prepares an unprocessed (undrawn) laminate 30 and places it on the Y stage 257. Next, the user instructs the drawing system 100 to draw on the laminate 30. The drawing system 100 then continuously irradiates the laminate 30 with laser light Lm, forming irregular stripe patterns extending in the X direction as drawing marks on multiple thermal recording layers (recording layers 13, 15, 17 and laser marking layer 36 or laser marking layer 38). At this time, the drawing system 100 temporarily stops irradiating the laser light Lm each time one line of laser light Lm is completed, and moves the Y stage 257 by a predetermined amount in the Y direction so that the laser light Lm can be irradiated to the next line. Once the movement of the Y stage 257 is complete, the drawing system 100 irradiates the laminate 30 with laser light Lm again.

[0205] The drawing system 100, for example, in the drawing process described above, draws the striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17 and laser marking layer 36 or laser marking layer 38) such that, in the spatial frequency spectrum of image data 21 obtained by imaging with ring illumination, there is a periodic peak Py in the Y-direction spatial frequency profile that is not present in the X-direction spatial frequency profile. The drawing system 100, for example, draws the striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17 and laser marking layer 36 or laser marking layer 38) such that, when the X-direction spatial frequency profile and the Y-direction spatial frequency profile are superimposed on each other, the intensity ratio at the position of the peak Py satisfies the above equation (S2 / S1≧1.2). The drawing system 100 draws a striped pattern 21a on multiple thermal recording layers (recording layers 13, 15, 17 and laser marking layer 36 or laser marking layer 38) such that, for example, the X direction is parallel to one edge of the recording medium 10 and the Y direction is parallel to another edge of the recording medium 10 that is perpendicular to the aforementioned edge. In this way, the drawn object 40 is formed.

[0206] In this modified example, in addition to the recording layers 13, 15, and 17, laser marking layers 36 and 38 are provided. This allows the laser marking layers 36 and 38 to produce black or dark colors, thus achieving a higher contrast display than full-color display using only the recording layers 13, 15, and 17.

[0207] In this modified example, the drawing unit 350 shown in Figure 23 may be used as a drawing unit capable of performing laser drawing on the laser marking layers 36 and 38. In this case, laser drawing on the recording layers 13, 15, and 17 can be performed by the drawing unit 150, and laser drawing on the laser marking layers 36 and 38 can be performed by the drawing unit 350. In other words, in this modified example, the optical system for performing laser drawing on the recording layers 13, 15, and 17 and the optical system for performing laser drawing on the laser marking layers 36 and 38 are provided separately from each other.

[0208] The drawing unit 350 includes, for example, a signal processing circuit 351, a laser drive circuit 352, a light source unit 353, an X scanner drive circuit 354, an X scanner unit 355, a Y stage drive circuit 356, and a Y stage 357, as shown in Figure 24. The drawing unit 350 can perform drawing on the laminate 30 by controlling the output of the light source unit 353 based on a voltage value file (list of command voltage values) input from the information processing unit 160.

[0209] The signal processing circuit 351 is capable of acquiring a voltage value file (a list of command voltage values) input from the information processing unit 160 as an image signal Din. The signal processing circuit 351 is capable of generating a pixel signal Dout from the image signal Din, for example, according to the scanner operation of the X scanner unit 355. The pixel signal Dout causes the light source unit 353 (for example, the light source 53D described later) to output laser light with power corresponding to the command voltage value. Together with the laser drive circuit 352, the signal processing circuit 351 is capable of controlling the peak value of the current applied to the light source unit 353 (for example, the light source 53D) according to the pixel signal Dout.

[0210] The laser driving circuit 352 is capable of driving the light source 53D of the light source unit 353 according to, for example, the pixel signal Dout. The laser driving circuit 352 is capable of controlling the brightness (brightness / darkness) of the laser light in order to draw an image corresponding to the pixel signal Dout. The laser driving circuit 352 has, for example, a driving circuit 52D that drives the light source 53D.

[0211] The light source 53D can perform drawing on the laminate 30 by outputting laser light with power corresponding to the command voltage value to the laminate 30. The light source 53D is capable of emitting laser light in the near-infrared region. For example, the light source 53D is an excimer laser that emits laser light Ld with an emission wavelength λ4 that can be recorded on the laser marking layers 36 and 38.

[0212] The light source unit 353 includes a light source 53D. The laser beam Ld emitted from the light source 53D is formed into substantially parallel light (collimated light) by, for example, a collimating lens. The light source unit 353 can output the substantially collimated laser beam Ld to the X scanner unit 355.

[0213] The X scanner driving circuit 354 can drive the X scanner unit 355 based on, for example, a control signal input from the signal processing circuit 351. In addition, when a signal related to the irradiation angle of the uniaxial scanner 55a or the like is input from the X scanner unit 355, the X scanner driving circuit 354 can drive the X scanner unit 355 to achieve a desired irradiation angle based on the signal.

[0214] The X scanner unit 355 can scan the laser beam Ld incident from the light source unit 353 in the X-axis direction on the surface of the laminate 30, for example. The X scanner unit 355 includes, for example, a uniaxial scanner 55a and an fθ lens 55b. The uniaxial scanner 55a is, for example, a galvanometer mirror that scans the laser beam Ld incident from the light source unit 353 in the X-axis direction on the surface of the laminate 30 based on a driving signal input from the X scanner driving circuit 354. The fθ lens 55b can convert the constant-speed rotational movement by the uniaxial scanner 55a into constant-speed linear movement of a spot moving on the focal plane (the surface of the laminate 30).

[0215] The Y stage driving circuit 356 can drive the Y stage 357 based on, for example, a control signal input from the signal processing circuit 351. By displacing the Y stage 357 in the Y-axis direction at a predetermined speed, the Y stage 357 can move the laminate 30 placed on the Y stage 357 in the Y-axis direction relative to the X scanner unit 355 at a predetermined speed. Through the cooperative operation of the X scanner unit 355 and the Y stage 357, the laser beam Ld can raster-scan the surface of the laminate 30.

[0216] Next, an example of writing information in the drawing system 100 according to this modified example will be described.

[0217] First, the user prepares an uncolored laminate 30 and places it on the Y stage 157 of the drawing unit 150. Next, the user transmits input image data described in the RGB color space to the drawing system 100 via the network from a terminal device. When the drawing system 100 receives the input image data via the network, it executes the following drawing process.

[0218] First, when the information processing unit 160 receives input image data via the communication unit 110, it converts the input image data, which is described in the RGB color space, into leuco image data described in the leuco color space and monochrome image data described in a black or dark color space. Next, the information processing unit 160 derives a voltage value file (list of command voltage values) based on the gradation values ​​of each color at each drawing coordinate of the leuco image data and monochrome image data obtained by the conversion. The information processing unit 160 transmits the voltage value file (list of command voltage values) derived based on the gradation values ​​of each color at each drawing coordinate of the leuco image data to the drawing unit 150. The information processing unit 160 further transmits a voltage value file (list of command voltage values) derived based on the gradation values ​​of each color at each drawing coordinate of the monochrome image data to the drawing unit 250.

[0219] The signal processing circuit 151 of the drawing unit 150 acquires a voltage value file (list of command voltage values) input from the information processing unit 160 as an image signal Din. From the image signal Din, the signal processing circuit 151 generates an image signal synchronized with the scanner operation of the X scanner unit 155, according to the characteristics of the laser light, such as the wavelength. In the generated image signal, the signal processing circuit 151 converts the image signal for one line corresponding to one scanner operation into a continuous signal that outputs laser light continuously over time. The signal processing circuit 151 outputs the projected image signal thus generated to the laser drive circuit 152 of the drawing unit 150. The projected image signal is a signal that outputs one line of laser light continuously over time to each light source 53A, 53B, 53C, and is not a signal that outputs one line of laser light intermittently.

[0220] The laser driving circuit 152 drives each of the light sources 53A, 53B, and 53C of the light source unit 153 according to the projection image signal corresponding to each wavelength. At this time, the laser driving circuit 152 emits laser light from at least one of the light sources 53A, 53B, and 53C and scans it on the laminate 30.

[0221] For example, to colorize the recording layer 13, a laser beam La with an emission wavelength λ1 is irradiated onto the recording layer 13 with an energy sufficient to reach the color-developing temperature. This causes the photothermal converter contained in the recording layer 13 to generate heat, and a color reaction occurs between the color-developing compound and the symmetric / dechromizing agent, resulting in the irradiated area developing a color, for example, magenta. Similarly, to colorize the recording layer 15, a laser beam Lb with an emission wavelength λ2 is irradiated onto the recording layer 15 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, cyan. To color the recording layer 17, a laser beam Lc with an emission wavelength λ3 is irradiated onto the recording layer 17 with an energy sufficient to reach the color-developing temperature, resulting in the irradiated area developing a color, for example, yellow. In this way, by irradiating any part with laser light of the corresponding wavelength, it becomes possible to record patterns, etc. (for example, full-color patterns, etc.).

[0222] The mechanism, consisting of an X-scanner drive circuit 154, an X-scanner unit 155, a Y-stage drive circuit 156, and a Y-stage 157, functions as a scanning unit that irradiates the surface of the laminate 30 with laser light Lm generated by the light source unit 153. Preferably, the size and shape of the irradiation spot of the laser light Lm are such that the high-temperature region generated on the recording layer 13 and its periphery by the laser light La contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm. Furthermore, preferably, the size and shape of the irradiation spot of the laser light Lm are such that the high-temperature region generated on the recording layer 15 and its periphery by the laser light Lb contained in the laser light Lm does not overlap with the high-temperature region generated on the recording layer 17 and its periphery by the laser light Lc contained in the laser light Lm.

[0223] Next, the user places the stacked body 30 drawn by the drawing unit 150 onto the Y-stage 357 of the drawing unit 350. At this time, it is preferable that the coordinates of the Y-stage 357 of the drawing unit 150 correspond to the coordinates of the Y-stage 357 of the drawing unit 350. It is also preferable that the reference coordinates in the drawing unit 150 correspond to the reference coordinates in the drawing unit 350.

[0224] Subsequently, the signal processing circuit 351 of the drawing unit 350 acquires the voltage value file (list of command voltage values) input from the information processing unit 160 as an image signal Din. From the image signal Din, the signal processing circuit 351 generates an image signal synchronized with the scanner operation of the X scanner unit 355, according to the characteristics of the laser light, such as the wavelength. In the generated image signal, the signal processing circuit 351 converts the image signal for one line corresponding to one scanner operation into a continuous signal that outputs laser light continuously over time. The signal processing circuit 251 outputs the projected image signal thus generated to the laser drive circuit 352 of the drawing unit 350. The projected image signal is a signal that outputs one line of laser light continuously over time to the light source 53D, and is not a signal that outputs one line of laser light intermittently.

[0225] The laser drive circuit 352 drives the light source 53D of the light source unit 353 according to a projection image signal corresponding to the wavelength. At this time, the laser drive circuit 352, for example, emits laser light from the light source 53D and scans it on the laminate 30.

[0226] For example, by irradiating the laser marking layers 36 and 38 with laser light Ld having an emission wavelength λ4 at an energy level sufficient to reach the color temperature of the laser marking layers 36 and 38, a color such as black or a dark color will be produced in the irradiated area. In this way, by irradiating any area with laser light of the corresponding wavelength, it becomes possible to record patterns, etc. (for example, full-color patterns, etc.).

[0227] The mechanism, consisting of an X-scanner drive circuit 354, an X-scanner unit 355, a Y-stage drive circuit 356, and a Y-stage 357, functions as a scanning unit that irradiates the surface of the laminate 30 with laser light Ld generated by the light source unit 353. The size and shape of the irradiation spot of the laser light Ld are preferably such that the high-temperature region generated in the laser marking layer 38 and its surroundings by the laser light Ld does not overlap with the recording layer 17. Furthermore, it is preferable that the high-temperature region generated in the laser marking layer 36 and its surroundings by the laser light Ld contained in the laser light Lm does not overlap with the recording layer 13.

[0228] An example has been described in which laser drawing is performed on the recording layers 13, 15, and 17 followed by laser drawing on the laser marking layers 36 and 38. However, the order of laser drawing is not limited to this order. For example, laser drawing may be performed on the laser marking layers 36 and 38 followed by laser drawing on the recording layers 13, 15, and 17.

[0229] [Differentiation Example E] In the modified example D described above, the light source unit 253 of the drawing unit 250 may be capable of generating multiple laser beams La, Lb, Lc, Ld such that the irradiation spots of multiple laser beams La, Lb, Lc, Ld are arranged at predetermined gaps in a direction that intersects the scanning direction of the multiple laser beams La, Lb, Lc, Ld at an angle greater than 0 degrees and less than 90 degrees, as shown in Figure 25, so that the multiple laser beams La, Lb, Lc, Ld are scanned on the surface of the laminate 30. The laser beams La, Lb, Lc, Ld may be scanned in the X-axis direction with predetermined gaps in a direction that intersects the X-axis direction and the Y-axis direction at an angle oblique to the X-axis direction, as shown in Figure 26. The laser beams La, Lb, Lc, Ld may be scanned in the X-axis direction with predetermined gaps in a direction perpendicular to the X-axis direction (Y-axis direction), for example.

[0230] Here, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may overlap. In this case, the optical system is configured such that the optical axis of the laser beam La reflected by the dichroic mirror 53b and the optical axis of the laser beam Lb transmitted through the dichroic mirror 53b intersect at a predetermined angle.

[0231] Furthermore, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may not completely overlap and may be offset from each other. Also, in the dichroic mirror 53b, the spot where the laser beam La is reflected and the spot where the laser beam Lb is transmitted may be separated from each other. In these cases, the optical system may be configured such that the optical axis of the laser beam La reflected by the dichroic mirror 53b and the optical axis of the laser beam Lb transmitted through the dichroic mirror 53b intersect at a predetermined angle, or the optical system may be configured so that they are parallel to each other.

[0232] In the dichroic mirror 53c, the optical system is configured such that the spots transmitted by the laser light La or laser light Lb and the spots reflected by the laser light Lc or laser light Ld do not completely overlap with each other, but are offset. In this case, in the dichroic mirror 53c, the spots transmitted by the laser light La, the spots transmitted by the laser light Lb, the spots reflected by the laser light Lc, and the spots reflected by the laser light Ld may be aligned with a slight offset in a predetermined direction. In the dichroic mirror 53c, the spots transmitted by the laser light La, the spots transmitted by the laser light Lb, the spots reflected by the laser light Lc, and the spots reflected by the laser light Ld may be aligned with a predetermined gap between them.

[0233] In these cases, the optical system may be configured such that the optical axis of the laser beam La transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lb transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lc reflected by the dichroic mirror 53c, and the optical axis of the laser beam Ld reflected by the dichroic mirror 53c intersect each other at a predetermined angle. At this time, the light source unit 253 outputs multiple laser beams La, Lb, Lc, and Ld to the X scanner unit 255 with the optical axes of the multiple laser beams La, Lb, Lc, and Ld offset from each other, and also outputs multiple laser beams La, Lb, Lc, and Ld to the X scanner unit 255 such that the optical axes of the multiple laser beams La, Lb, Lc, and Ld intersect each other at a predetermined angle.

[0234] Alternatively, the optical system may be configured such that the optical axis of the laser beam La transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lb transmitted through the dichroic mirror 53c, the optical axis of the laser beam Lc reflected by the dichroic mirror 53c, and the optical axis of the laser beam Ld reflected by the dichroic mirror 53c are parallel to each other. In this case, the light source unit 253 outputs multiple laser beams La, Lb, Lc, and Ld to the X scanner unit 255 with the optical axes of the multiple laser beams La, Lb, Lc, and Ld offset from each other, and also outputs multiple laser beams La, Lb, Lc, and Ld to the X scanner unit 255 such that the optical axes of the multiple laser beams La, Lb, Lc, and Ld are parallel to each other with a predetermined gap between them.

[0235] In this modified example, multiple laser beams La, Lb, Lc, and Ld are arranged at predetermined gaps in a direction intersecting the scanning direction of the multiple laser beams La, Lb, Lc, and Ld, and the multiple laser beams La, Lb, Lc, and Ld are scanned on the surface of the laminate 30. This makes it possible to achieve raster scanning while reducing thermal crosstalk.

[0236] In this modified example, an X-scanner capable of scanning the laser light Ld incident from the light source unit 25D in the X-axis direction on the surface of the laminate 30 may be provided separately from the X-scanner unit 255. In this case, the X-scanner for the laser light Ld may include, for example, a 1-axis scanner and an fθ lens. Here, the 1-axis scanner for the laser light Ld is, for example, a galvano mirror that scans the laser light Ld incident from the light source unit 25D in the X-axis direction on the surface of the laminate 30 based on a drive signal input from the X-scanner drive circuit 254. The fθ lens for the laser light Ld is, for example, capable of converting the uniform rotational motion of the 1-axis scanner for the laser light Ld into the uniform linear motion of a spot moving on the focal plane (the surface of the laminate 30). Even with such a configuration, raster scanning using multiple laser beams La, Lb, Lc, and Ld can be realized.

[0237] The effects described herein are for illustrative purposes only. The effects of this disclosure are not limited to those described herein. This disclosure may have effects other than those described herein.

[0238] Furthermore, for example, this disclosure can take the following form. (1) The laminate comprises multiple first thermal recording layers, each having a different color and light absorption wavelength band in its colored state, stacked with an insulating layer in between. Each of the first thermal recording layers comprises a color-developing compound whose color in the color-developing state is different from that of the other, and a matrix resin that disperses the color-developing compound. The plurality of first thermal recording layers have irregular stripe patterns extending in a first direction, which are drawn on the surface of the laminate as marks created by irradiating it with laser light. A drawing. (2) Each of the first thermal recording layers further comprises a second thermal recording layer having a different recording method. (1) The drawing described above. (3) The striped pattern is drawn on the plurality of first thermal recording layers such that, in the spatial frequency spectrum of the image data obtained by imaging the striped pattern using ring illumination, the profile in the second direction orthogonal to the first direction has periodic peaks that are not present in the profile in the first direction. The drawing described in (1) or (2). (4) When the profile in the first direction and the profile in the second direction are superimposed on each other, the intensity ratio at the peak position satisfies the following equation. (3) The drawings described above. S2 / S1 ≥ 1.2 S1: Intensity at the peak position of the profile in the first direction. S2: Intensity at the peak position of the profile in the second direction. (5) The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The first direction is parallel to the first edge of the laminate, The second direction is the direction of the laminate that is parallel to the second edge perpendicular to the first edge. (3) or (4) the drawings described therein. (6) The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The first and second directions are directions that intersect diagonally with all the edges of the laminate. (3) or (4) the drawings described therein. (7) Each of the first thermal recording layers includes a photothermal converter having different light absorption wavelength bands. A drawing described in any one of (1) through (6). (8) The plurality of first thermal recording layers have irregular stripe patterns extending in the first direction as drawing marks created by continuous irradiation of the laminate surface with laser light in the scanning direction. A drawing described in any one of (1) through (7). (9) The present invention provides a laminate comprising a plurality of first thermal recording layers having different colors and light absorption wavelength bands in the colored state, laminated with an insulating layer in between, wherein each of the first thermal recording layers comprises a color-developing compound having different colors in the colored state, and a matrix resin that disperses the color-developing compound, thereby providing a drawing material. The plurality of first thermal recording layers are irradiated with a first laser beam to form a first stripe pattern of irregular width extending in a first direction as a drawing mark on the plurality of first thermal recording layers. including A method for creating a drawing. (10) The drawing further comprises a second thermal recording layer having a recording method different from that of each of the first thermal recording layers. This includes irradiating the second thermal recording layer with a second laser beam and forming a second stripe pattern on the second thermal recording layer using a recording method different from that of each of the first thermal recording layers. (9) Method for forming the drawing described above. (11) The method includes drawing the first stripe pattern on the plurality of first thermal recording layers such that, in the spatial frequency spectrum of the image data obtained by imaging the first stripe pattern using ring illumination, there are periodic peaks in the profile of a second direction orthogonal to the first direction that are not present in the profile of the first direction. A method for forming the drawing described in (9) or (10). (12) This includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the intensity ratio at the peak position when the profile in the first direction and the profile in the second direction are superimposed on each other satisfies the following equation. A method for forming the drawing described in (9) or (10). S2 / S1 ≥ 1.2 S1: Intensity at the peak position of the profile in the first direction. S2: Intensity at the peak position of the profile in the second direction. (13) The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The method includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the first direction is parallel to the first edge of the laminate and the second direction is parallel to the second edge of the laminate that is perpendicular to the first edge. A method for forming a drawing according to any one of (9) to (12). (14) The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. This includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the first and second directions intersect diagonally with all the edges of the laminate. A method for forming a drawing according to any one of (9) to (12). (15) Each of the first thermal recording layers contains a photothermal converter with light absorption wavelength bands that are different from each other. The process includes generating heat in the photothermal converter by irradiating the plurality of first thermal recording layers with the first laser light, thereby causing the color-developing compound to change color, and thereby forming the first stripe pattern as a drawing mark on the plurality of first thermal recording layers. A method for forming a drawing as described in any one of (9) to (14). (16) This includes continuously irradiating the plurality of first thermal recording layers with the first laser light in the scanning direction. A method for forming a drawing as described in any one of (9) to (15). (17) The laminate comprises multiple thermal recording layers, each having a different color and light absorption wavelength band in its colored state, stacked with an insulating layer in between. The plurality of thermal recording layers have irregular stripe patterns extending in a first direction, which are drawn on the surface of the laminate as marks created by irradiating it with laser light. A drawing. (18) To prepare a drawing object comprising a laminate in which multiple thermal recording layers with different color and light absorption wavelength bands in the colored state are stacked with an insulating layer in between, By irradiating the laminate with laser light, a drawing is formed on the plurality of thermal recording layers as a drawing trace, forming irregular stripe patterns of varying widths extending in a first direction. including A method for creating a drawing. (19) A drawing system for a drawing object comprising a laminate in which a plurality of first thermal recording layers having different colors and light absorption wavelength bands in their colored state are stacked with an insulating layer in between, and a second thermal recording layer having a different recording method than each of the first thermal recording layers, A first light source capable of generating first laser light including a first wavelength corresponding to the optical absorption wavelength band of each of the first thermal recording layers, A second light source capable of generating a second laser beam including a second wavelength recordable on the second thermal recording layer, A first optical system that guides the first laser light emitted from the first light source to the laminate, A second optical system that guides the second laser light emitted from the second light source to the second thermal recording layer, Equipped with A drawing system. (20) The first optical system and the second optical system are configured by a single optical system. The drawing system described in (19). (twenty one) The first optical system and the second optical system are provided separately from each other. The drawing system described in (19).

[0239] This application claims priority based on Japanese Patent Application No. 2022-042855, filed with the Japan Patent Office on 17 March 2022, and all contents of that application are incorporated herein by reference.

[0240] Those skilled in the art will understand that various modifications, combinations, subcombinations, and changes can be conceived depending on design requirements and other factors, and that these fall within the scope of the attached claims and their equivalents.

Claims

1. A laminate in which multiple first thermal recording layers, each having a different color and light absorption wavelength band in its colored state, are stacked with an insulating layer in between, Each of the first thermal recording layers has a second thermal recording layer with a different recording method from the first thermal recording layer. Equipped with, Each of the first thermal recording layers comprises a color-developing compound whose color in the color-developing state is different from that of the other, and a matrix resin that disperses the color-developing compound. The plurality of first thermal recording layers have a first stripe pattern of irregular width extending in a first direction, which is drawn on the surface of the laminate as a drawing mark by irradiation with laser light. The second thermal recording layer has markings drawn on its surface by irradiation with laser light. The drawing marks on the plurality of first thermal recording layers and the drawing marks on the second thermal recording layer are formed so that they can be independently identified and viewed. A drawing.

2. The first stripe pattern is drawn on the plurality of first thermal recording layers such that, in the spatial frequency spectrum of the image data obtained by imaging the first stripe pattern using ring illumination, the profile in the second direction orthogonal to the first direction has periodic peaks that are not present in the profile in the first direction. The drawing according to claim 1.

3. When the profile in the first direction and the profile in the second direction are superimposed on each other, the intensity ratio at the peak position satisfies the following equation. The drawing according to claim 2. S2 / S1 ≥ 1.2 S1: Intensity of the profile in the first direction at the peak position. S2: Intensity of the profile in the second direction at the peak position.

4. The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The first direction is parallel to the first edge of the laminate, The second direction is the direction of the laminate that is parallel to the second edge perpendicular to the first edge. The drawing according to claim 2.

5. The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The first and second directions are directions that intersect diagonally with all the edges of the laminate. The drawing according to claim 2.

6. Each of the first thermal recording layers includes a photothermal converter having different light absorption wavelength bands. The drawing according to claim 1.

7. The plurality of first thermal recording layers have irregular stripe patterns extending in the first direction as drawing marks created by continuous irradiation of the laminate surface with laser light in the scanning direction. The drawing according to claim 1.

8. The second thermal recording layer is arranged at least in a location facing the laminate. The drawing according to claim 1.

9. The second thermal recording layer is arranged only in locations that are not facing the laminate. The drawing according to claim 1.

10. A laminate comprising a plurality of first thermal recording layers having different colors and light absorption wavelength bands in the colored state, laminated with an insulating layer in between, and a second thermal recording layer having a different recording method from each of the first thermal recording layers, wherein each of the first thermal recording layers includes a color-developing compound having different colors in the colored state, and a matrix resin that disperses the color-developing compound, to prepare a drawing object. The plurality of first thermal recording layers are irradiated with a first laser beam to form a first stripe pattern of irregular width extending in a first direction as a drawing mark on the plurality of first thermal recording layers, The second thermal recording layer is irradiated with a second laser beam, and a drawing mark is formed on the second thermal recording layer using a recording method different from that of each of the first thermal recording layers. Includes, The drawing marks on the plurality of first thermal recording layers and the drawing marks on the second thermal recording layer are formed so that they can be independently identified and viewed. A method for creating a drawing.

11. The method includes drawing the first stripe pattern on the plurality of first thermal recording layers such that, in the spatial frequency spectrum of the image data obtained by imaging the first stripe pattern using ring illumination, there are periodic peaks in the profile in the second direction orthogonal to the first direction that are not present in the profile in the first direction. A method for forming a drawing according to claim 10.

12. This includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the intensity ratio at the peak position when the profile in the first direction and the profile in the second direction are superimposed on each other satisfies the following equation. A method for forming a drawing according to claim 10. S2 / S1 ≥ 1.2 S1: Intensity of the profile in the first direction at the peak position. S2: Intensity of the profile in the second direction at the peak position.

13. The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The method includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the first direction is parallel to the first edge of the laminate and the second direction is parallel to the second edge of the laminate that is perpendicular to the first edge. A method for forming a drawing according to claim 10.

14. The aforementioned laminate is a sheet-like or plate-like laminate that has a rectangular shape in plan view. The method includes drawing the first stripe pattern on the plurality of first thermal recording layers such that the first and second directions intersect diagonally with all the edges of the laminate. A method for forming a drawing according to claim 10.

15. Each of the first thermal recording layers contains a photothermal converter with light absorption wavelength bands that are different from each other. The process includes irradiating the plurality of first thermal recording layers with the first laser light to generate heat in the photothermal conversion agent, thereby causing the color-developing compound to change color, and thereby forming the first stripe pattern as a drawing mark on the plurality of first thermal recording layers. A method for forming a drawing according to claim 10.

16. This includes continuously irradiating the plurality of first thermal recording layers with the first laser light in the scanning direction. A method for forming a drawing according to claim 10.

17. The drawing is applied to medical supplies, automotive parts, automobiles, toys, food, cosmetics, clothing, documents, exterior components, or electronic equipment casings. The drawing according to any one of claims 1 to 9.

18. The drawing is a security card, a financial settlement card, an ID card, or a personal transaction card. The drawing according to any one of claims 1 to 9.

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