Laser recording device and laser recording method

Abstract

To provide a laser recording device capable of high-quality color reproduction. [Solution] A laser recording apparatus according to one embodiment for recording an image on a medium having multiple color-emitting layers that emit different colors when exposed to light of different wavelengths comprises a plurality of laser units provided corresponding to the plurality of color-emitting layers, each laser unit emitting laser light of a wavelength that causes the corresponding color-emitting layer to emit color. One pixel is formed by multiple adjacent color marks in the in-plane direction of the medium.

Description

Technical Field

[0001] Embodiments of the present invention relate to a laser recording apparatus and a laser recording method.

Background Art

[0002] There are roughly two main methods for recording a full-color image on a medium by irradiating laser light.

[0003] The first method is to control the time and intensity of the laser light irradiated onto a medium in which a single photothermal conversion layer containing a photothermal conversion agent and a plurality of color-forming layers with different threshold temperatures are laminated, so as to selectively cause the plurality of color-forming layers to form colors. For example, the medium includes three color-forming layers corresponding to the three primary colors.

[0004] The second method is to irradiate laser light with a wavelength corresponding to the color-forming layer to be colored onto a medium in which a plurality of color-forming layers having absorption characteristics at different wavelengths are laminated, so as to selectively cause the plurality of color-forming layers to form colors. For example, the medium includes three color-forming layers corresponding to the three primary colors.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the second method described above, as will be described below, there is a possibility that the color of each pixel forming a full-color image may be a color different from the desired color.

[0007] As shown in the left portion of Figure 10, the medium 1000 used in the second method comprises color-developing layers 1001 to 1003 laminated on a substrate (not shown) that develop different colors when exposed to light of different wavelengths. A transparent heat-insulating layer (not shown) is provided between the color-developing layers to suppress heat transfer.

[0008] In the second method, laser light of three different wavelengths is sequentially irradiated onto each position on the medium 1000 in the stacking direction, which is the direction in which the color-developing layers 1001 to 1003 are stacked. When laser light of the first wavelength is irradiated onto the medium 1000, the area in the color-developing layer 1001 centered on the irradiated position turns cyan. When laser light of the second wavelength is irradiated onto the medium 1000, the area in the color-developing layer 1002 centered on the irradiated position turns magenta. When laser light of the third wavelength is irradiated onto the medium 1000, the area in the color-developing layer 1003 centered on the irradiated position turns yellow. In this specification, the colored areas obtained by irradiating each position with laser light are called marks. As shown in the right-hand portion of Figure 10, the desired color is reproduced by the transmission synthesis of the three marks arranged in the stacking direction.

[0009] In medium 1000, two adjacent color-developing layers are separated by only a few microns. As a result, heat generated in a color-developing layer that is intended to be colored may be transferred to a color-developing layer that is not intended to be colored, causing that unintended layer to be colored. For example, when coloring layer 1003, heat generated in coloring layer 1003 may be transferred to coloring layer 1002, causing coloring layer 1002 to be colored. In particular, when coloring layers 1003, 1002, and 1001 are colored in this order, heat from coloring layer 1003 remains when coloring layer 1002, and heat from coloring layer 1002 remains when coloring layer 1001, making it easy for unintended color-developing layers to be colored. Due to the effects of such thermal interference, the color obtained by transmission synthesis may differ from the desired color.

[0010] The problem that this invention aims to solve is to provide a laser recording apparatus and a laser recording method capable of high-quality color reproduction. [Means for solving the problem]

[0011] According to one embodiment, a laser recording apparatus for recording an image on a medium having multiple color-emitting layers that emit different colors when exposed to light of different wavelengths comprises a plurality of laser units corresponding to the plurality of color-emitting layers, each laser unit emitting laser light of a wavelength that causes the corresponding color-emitting layer to emit color. One pixel is formed by multiple adjacent color marks in the in-plane direction of the medium. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a laser recording apparatus and a laser recording method capable of high-quality color reproduction. [Brief explanation of the drawing]

[0013] [Figure 1] A block diagram showing the hardware configuration of a laser recording device according to an embodiment. [Figure 2] A perspective view showing the structure of the medium according to the embodiment. [Figure 3] A block diagram showing the functional configuration of the control circuit included in the laser recording device according to the embodiment. [Figure 4] A diagram illustrating the laser recording method according to this embodiment. [Figure 5] A perspective view showing the distance between marks according to the embodiment. [Figure 6] A flowchart illustrating the laser recording process according to the embodiment. [Figure 7] A diagram illustrating how the size of the mark changes depending on the irradiation time and intensity of the laser light according to the embodiment. [Figure 8] A diagram illustrating how the size of the mark changes depending on the irradiation time and intensity of the laser light according to the embodiment. [Figure 9] A diagram showing the arrangement pattern of the three-colored marks according to the embodiment. [Figure 10] A diagram for explaining a laser recording method according to the prior art.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments will be described with reference to the drawings.

[0015] FIG. 1 schematically shows a hardware configuration example of a laser recording apparatus 100 according to an embodiment. The laser recording apparatus 100 shown in FIG. 1 records a color image on a medium 200 in which a plurality of color-developing layers that receive light of different wavelengths and develop colors of different colors are laminated by irradiation with laser light. For example, the laser recording apparatus 100 forms a color image corresponding to the input data on the medium 200 by irradiating the medium 200 with laser light while modulating the laser light according to the input data (for example, image data).

[0016] FIG. 2 schematically shows a structural example of the medium 200. As shown in FIG. 2, the medium 200 includes a base material 201, a color-developing layer 202 provided on the base material 201, a heat insulation layer 203 provided on the color-developing layer 202, a color-developing layer 204 provided on the heat insulation layer 203, a heat insulation layer 205 provided on the color-developing layer 204, a color-developing layer 206 provided on the heat insulation layer 205, and a protective layer 207 provided on the color-developing layer 206.

[0017] Typically, the medium 200 is a card-shaped or paper-shaped medium, and the base material 201 can be a plastic plate or paper. The protective layer 207 can be a transparent cover film. The heat insulation layer 203 is a transparent spacer layer that suppresses heat transfer between the color-developing layers 202 and 204, and the heat insulation layer 205 is a transparent spacer layer that suppresses heat transfer between the color-developing layers 204 and 206.

[0018] The color-developing layer 202 contains a photothermal converter that converts light of a first wavelength into heat, a cyan leuco dye, and a color developer. When laser light of the first wavelength is irradiated onto the color-developing layer 202, the photothermal converter contained in the color-developing layer 202 converts the laser light into heat. Heat is generated in the area of ​​the color-developing layer 202 irradiated with laser light, causing the color developer contained in the color-developing layer 202 to dissolve, and a chemical reaction occurs between the cyan leuco dye and the color developer, causing the cyan leuco dye to develop color. As a result, a cyan mark is formed in the color-developing layer 202 at the laser irradiation location.

[0019] The color-developing layer 204 contains a photothermal converter that converts light of a second wavelength into heat, a magenta leuco dye, and a color developer. When laser light of a second wavelength is irradiated onto the color-developing layer 204, the photothermal converter contained in the color-developing layer 204 converts the laser light into heat. Heat is generated in the area of ​​the color-developing layer 204 irradiated with laser light, causing the color developer contained in the color-developing layer 204 to dissolve, and a chemical reaction occurs between the magenta leuco dye and the color developer, causing the magenta leuco dye to develop color. As a result, a magenta mark is formed in the color-developing layer 204 at the location of the laser light irradiation.

[0020] The color-developing layer 206 contains a photothermal converter that converts light of a third wavelength into heat, a yellow leuco dye, and a color developer. When laser light of a third wavelength is irradiated onto the color-developing layer 206, the photothermal converter contained in the color-developing layer 206 converts the laser light into heat. Heat is generated in the area of ​​the color-developing layer 206 irradiated with laser light, causing the color developer contained in the color-developing layer 206 to dissolve, and a chemical reaction occurs between the yellow leuco dye and the color developer, causing the yellow leuco dye to develop color. As a result, a yellow mark is formed in the color-developing layer 206 at the location of the laser light irradiation.

[0021] The first wavelength, the second wavelength, and the third wavelength are different from each other. The first wavelength, the second wavelength, and the third wavelength are, for example, included in the near-infrared wavelength range.

[0022] In this embodiment, the medium 200 has a structure comprising three color-developing layers 202, 204, and 206 corresponding to the three primary colors, as shown in Figure 2. The color-developing layers contained in the medium 200 may be two layers or four or more layers.

[0023] Refer again to Figure 1. The laser recording device 100 comprises a control circuit 110, a group of laser units 120, an optical system (not shown), and a moving mechanism 130. The control circuit 110 is communicated with the group of laser units 120 and the moving mechanism 130.

[0024] The control circuit 110 includes, for example, a CPU (Central Processing Unit) 111, a memory 112, and a communication interface 113. The CPU 111 is connected to the memory 112 and the communication interface 113 in a communicative manner.

[0025] The CPU 111 is an example of a hardware processor. The memory 112 may include volatile memory such as RAM (Random Access Memory) and non-volatile memory such as a hard disk drive (HDD) or solid-state drive (SSD). The CPU 111 performs a series of processes described later by executing programs stored in the memory 112.

[0026] The communication interface 113 is an interface for communicating with an external device, and includes, for example, a wireless communication module. The CPU 111 receives data corresponding to images to be recorded on the medium 200 from the external device via the communication interface 113. Alternatively, the data may be provided to the laser recording device 100 using removable media such as a USB memory stick. In this case, the laser recording device 100 may further include a drive that performs the processing of reading data from the removable media and writing data to the removable media.

[0027] The laser recording device 100 may further include a console (not shown) that allows a human operator to operate the laser recording device 100. The console may be used, for example, to set various information such as resolution. Alternatively, the laser recording device 100 may be configured so that the operator can operate it using an external device connected via a communication interface 113.

[0028] The control circuit 110 acquires image data, generates pulse control data from the image data to control the laser unit group 120, and controls the laser unit group 120 according to the pulse control data. The series of processes for generating pulse control data from image data will be described later.

[0029] The laser unit group 120 comprises three laser units 121, 122, and 123, each corresponding to one of the three color-emitting layers 202, 204, and 206 contained in the medium 200. Laser unit 121 is configured to emit laser light of a first wavelength to color-emitting layer 202. Laser unit 122 is configured to emit laser light of a second wavelength to color-emitting layer 204. Laser unit 123 is configured to emit laser light of a third wavelength to color-emitting layer 206. The optical system is configured to guide the laser light emitted from laser units 121, 122, and 123 to the medium 200.

[0030] The moving mechanism 130 moves the medium 200 relative to the optical portion, which includes the laser unit group 120 and the optical system, in order to form an image in a recording area set on the medium 200. In this embodiment, the moving mechanism 130 is configured to move the medium 200. In other embodiments, the moving mechanism 130 may be configured to move the optical portion, which includes the laser unit group 120 and the optical system.

[0031] Figure 3 schematically shows an example of the functional configuration of the control circuit 110. As shown in Figure 3, the control circuit 110 comprises an acquisition unit 115, a conversion unit 116, a mark size information generation unit 117, a pulse control data generation unit 118, and a control unit 119. The acquisition unit 115, the conversion unit 116, the mark size information generation unit 117, the pulse control data generation unit 118, and the control unit 119 can be realized by the CPU 111 executing a program stored in the memory 112.

[0032] The acquisition unit 115 acquires image data corresponding to the image to be recorded on the medium 200.

[0033] The conversion unit 116 converts the image data acquired by the acquisition unit 115 into image data for laser recording. Specifically, the conversion unit 116 obtains image data for laser recording by converting the image data into a predetermined format. The predetermined format specifies, for example, the number of pixels and the color space. The number of pixels indicates the number of vertical pixels and horizontal pixels that constitute the image recorded on the medium 200. The number of pixels is changed, for example, according to the size of the recording area set on the medium 200 and the resolution set on the laser recording device 100. In this embodiment, the CMY color space corresponding to the three primary colors that the color-developing layers 202, 204, and 206 contained in the medium 200 produce is specified as the predetermined format. The image data for laser recording includes values ​​for each color for each pixel. Specifically, the image data for laser recording includes values ​​for yellow (Y), magenta (M), and cyan (C) for each pixel.

[0034] The mark size information generation unit 117 generates mark size information for each pixel, indicating the mark size for each color, from the laser recording image data obtained by the conversion unit 116. For each pixel, the mark size information generation unit 117 determines the mark size for each color from the values ​​of each color. Specifically, the mark size information generation unit 117 calculates the mark size for each color for each pixel such that the larger the color value, the larger the mark size. In one example, the color value can range from 0 to 255. When the color value is 0, the mark size is 0, and when the color value is 255, the mark size is the maximum value. The maximum mark size may depend on the resolution set in the laser recording device 100. The higher the resolution, the smaller the maximum mark size. The mark size information indicates the mark size for yellow (Y), magenta (M), and cyan (C) for each pixel.

[0035] The pulse control data generation unit 118 generates pulse control data for controlling the laser unit group 120 based on the mark size information generated by the mark size information generation unit 117. The pulse control data includes control data for controlling the laser units 121, 122, and 123. The control data for each laser unit indicates the irradiation parameters of the laser light for each pixel. The irradiation parameters include one or more parameters for modulating the laser light, such as irradiation time and intensity. In this embodiment, the irradiation parameters include irradiation time and intensity. Specifically, the pulse control data generation unit 118 calculates the irradiation time and intensity of the laser light for each pixel that can obtain the mark size for each color. The pulse control data generation unit 118 sends the pulse control data to the control unit 119.

[0036] The control unit 119 controls the laser unit group 120 according to the pulse control data generated by the pulse control data generation unit 118.

[0037] In this embodiment, as shown in Figure 4, one pixel is composed of three adjacent colored marks in the in-plane direction of the medium 200. In other words, the three colored marks constituting one pixel are arranged in a planar configuration when viewed from the stacking direction. The in-plane direction of the medium 200 is the direction along the main surface of the medium 200 and is perpendicular to the stacking direction. The three colored marks constituting one pixel are not limited to being arranged in a line, but may be placed, for example, at three positions corresponding to the vertices of an equilateral triangle. Furthermore, when viewed from the stacking direction, only one of magenta, cyan, and yellow is recorded at any given position. In other words, when viewed from the stacking direction, marks of each color are recorded in such a way that marks of one color do not overlap with marks of other colors. In this case, only one colored mark may exist in the stacking direction.

[0038] Figure 5 schematically shows the distance between marks in the conventional method and the distance between marks in this embodiment. In Figure 5, the distance between marks in the conventional method is d z In this embodiment, the distance between the marks is d x This is the distance d. z This corresponds to the distance between the color-developing layers, which is about a few microns. On the other hand, distance d x The distance is approximately several tens of microns, and the distance d x distance d z This makes it possible to make it larger. As a result, in this embodiment, the effect of heat generated when recording marks of other colors on marks of each color can be reduced, and marks of each color can be recorded in the specified color.

[0039] Furthermore, in this embodiment, where one pixel is composed of three adjacent colored marks in the planar direction, it is possible to record using the three laser units 121, 122, and 123 simultaneously, enabling high-speed recording.

[0040] The configurations shown in Figures 1 and 3 are merely illustrative, and the configuration of the laser recording device 100 is not limited to the examples shown in Figures 1 and 3. For example, it is also possible to have a configuration in which the acquisition unit 115 and the conversion unit 116 are performed by a personal computer (PC), and the laser recording device 100 receives laser recording image data from the PC.

[0041] Figure 6 schematically shows an example of the laser recording process procedure according to the embodiment. The process shown in Figure 6 is performed by the laser recording device 100 described above, with reference to Figures 1 and 3.

[0042] In step S601 of Figure 6, the acquisition unit 115 acquires image data corresponding to the image to be recorded on the medium 200. For example, the acquisition unit 115 receives image data from an external computer.

[0043] In step S602, the conversion unit 116 converts the data obtained in step S601 into laser recording image data that shows the values ​​of each of multiple colors for each of a predetermined number of pixels. The multiple colors are cyan, magenta, and yellow, which correspond to the color-developing layers 202, 204, and 206 contained in the medium 200, respectively. In this embodiment, the laser recording image data includes the cyan value, the magenta value, and the yellow value for each of a predetermined number of pixels.

[0044] In step S603, the mark size information generation unit 117 generates mark size information indicating the mark sizes of multiple colors for each of a predetermined number of pixels from the laser recording image data obtained in step S602. In this embodiment, the mark size information includes the cyan mark size, magenta mark size, and yellow mark size for each of the predetermined number of pixels. For each pixel, the mark size information generation unit 117 calculates the cyan mark size from the cyan value included in the laser recording image data, the magenta mark size from the magenta value included in the laser recording image data, and the yellow mark size from the yellow value included in the laser recording image data.

[0045] In step S604, the pulse control data generation unit 118 generates pulse control data for each of a predetermined number of pixels, indicating the irradiation parameters of the laser units 121, 122, and 123, based on the mark size information obtained in step S603.

[0046] In step S605, the control unit 119 controls the laser unit group 120 and the moving mechanism 130 according to the pulse control data obtained in step S604 to record an image on the medium 200. For example, the control unit 119 uses the moving mechanism 130 to move the medium 200 to record at a pixel position on the medium 200, and simultaneously uses the laser units 121, 122, and 123 to record three marks that make up one pixel. Then, using the moving mechanism 130 to move the medium 200 to record at the next pixel position on the medium 200, and simultaneously uses the laser units 121, 122, and 123 to record three marks that make up one pixel. By repeating this operation, pixels that make up an image are successively recorded on the medium 200, and finally an image is formed on the medium 200.

[0047] As described above, the medium 200 includes color-emitting layers 202, 204, and 206 that emit different colors when exposed to light of different wavelengths, and the laser recording device 100 records an image on the medium 200 using laser units 121, 122, and 123 provided corresponding to each of the color-emitting layers 202, 204, and 206, such that three adjacent color marks in the in-plane direction of the medium 200 constitute one pixel. Constituting one pixel with three adjacent color marks in the in-plane direction of the medium 200 includes emitting color on a single color-emitting layer among the color-emitting layers 202, 204, and 206 in the stacking direction of the color-emitting layers 202, 204, and 206.

[0048] According to the above configuration, it becomes possible to increase the distance between marks in the stacking direction compared to conventional technology, thereby reducing the influence of heat generated when recording marks of other colors on marks of each color, and making it possible to record marks of each color in the specified color. As a result, high-quality color reproduction becomes possible. In addition, it is not necessary to determine the distribution of colors while considering thermal interference.

[0049] In this embodiment, the medium 200 includes three color-developing layers 202, 204, and 206, and the laser recording device 100 includes three laser units 121, 122, and 123 corresponding to each of the three color-developing layers 202, 204, and 206. This allows full-color images to be recorded on the medium 200 with high-quality color reproduction.

[0050] As in this embodiment, arranging the marks constituting one pixel in a planar array presents the problem that the pixels become larger than those produced by the conventional method shown in Figure 10. This problem can be solved by using a laser whose irradiation time and intensity can be arbitrarily set. As a result, as shown in Figure 7, the size of one pixel can be increased by increasing the irradiation time and intensity of the laser light, and as shown in Figure 8, the size of one pixel can be decreased by decreasing the irradiation time and intensity of the laser light.

[0051] Furthermore, the laser recording device 100 allows for arbitrary setting of the recording position. This makes it possible to change the arrangement pattern of the three color marks for each pixel, as shown in Figure 9. In the example shown in Figure 9, pixel 910 has the cyan mark 911, the yellow mark 912, and the magenta mark 913 in that order; pixel 920 has the yellow mark 921, the magenta mark 922, and the cyan mark 923 in that order; and pixel 930 has the magenta mark 931, the cyan mark 932, and the yellow mark 933 in that order. In addition, two vertically adjacent pixels are offset horizontally. For example, pixel 920 is shifted horizontally by 1 / 6 of a pixel relative to pixel 910. This makes it possible to densely arrange the marks of each color. By changing the arrangement pattern of the three color marks for each pixel in this way, higher quality color reproduction becomes possible.

[0052] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0053] 100...Laser recording device, 110...Control circuit, 111...CPU, 112...Memory, 113...Communication interface, 115...Acquisition unit, 116...Conversion unit, 117...Mark size information generation unit, 118...Pulse control data generation unit, 119...Control unit, 120...Laser unit group, 121...Laser unit, 122...Laser unit, 123...Laser unit, 130...Movement mechanism, 200...Media, 201...Substrate, 202, 204, 206...Coloring layer, 203, 205...Thermal barrier layer, 207...Protective layer, 1000...Media, 1001~1003...Coloring layer.

Claims

1. A laser recording device for recording an image on a medium having multiple color-emitting layers stacked on top of each other, which emit different colors when exposed to light of different wavelengths, A plurality of laser units provided corresponding to the plurality of color-emitting layers, each of which emits laser light of a wavelength that causes the corresponding color-emitting layer to color, comprising a plurality of laser units, A single pixel is formed by multiple adjacent colored marks in the in-plane direction of the aforementioned medium. Laser recording device.

2. The laser recording apparatus according to claim 1, wherein only one of the multiple color-emitting layers is color-emitting in the stacking direction, which is the direction in which the multiple color-emitting layers are stacked.

3. The laser recording apparatus according to claim 1, wherein the distance between two adjacent marks contained in one pixel is longer than the distance between two adjacent color-producing layers.

4. The plurality of color-producing layers include a first color-producing layer that produces a first color when it receives light of a first wavelength, a second color-producing layer that produces a second color when it receives light of a second wavelength, and a third color-producing layer that produces a third color when it receives light of a third wavelength. The plurality of laser units include a first laser unit that emits laser light of the first wavelength, a second laser unit that emits laser light of the second wavelength, and a third laser unit that emits laser light of the third wavelength. The first wavelength, the second wavelength, and the third wavelength are different from each other, and the first color, the second color, and the third color are different from each other. The aforementioned pixel includes the first color mark, the second color mark, and the third color mark, which are adjacent to each other in the in-plane direction of the medium. The laser recording apparatus according to claim 1.

5. The arrangement pattern of the first color mark, the second color mark, and the third color mark in the first pixel included in the image is different from the arrangement of the first color mark, the second color mark, and the third color mark in the second pixel included in the image. The laser recording apparatus according to claim 4.

6. The system further includes a control unit that controls the plurality of laser units, The control unit simultaneously drives the first laser unit, the second laser unit, and the third laser unit to form the pixel in the medium. The laser recording apparatus according to claim 4.

7. A laser recording method performed by a laser recording device that records an image on a medium having multiple color-emitting layers stacked on top of each other, which emit different colors when exposed to light of different wavelengths, The system includes a plurality of laser units provided corresponding to the plurality of color-emitting layers, each emitting laser light of a wavelength that causes the corresponding color-emitting layer to develop color, and recording an image on the medium using the plurality of laser units. A single pixel is formed by multiple adjacent colored marks in the in-plane direction of the aforementioned medium. Laser recording method.

Images