Printing apparatus and printing method

Abstract

To make high visibility and high-speed printing compatible with each other without increasing the size and cost of an apparatus and shortening the life of the apparatus.SOLUTION: The printer can print an arbitrary pattern by irradiating a surface to be printed of a printing object with a laser beam, and includes a laser beam generation part for oscillating the laser beam, a laser beam diameter adjustment part for adjusting the beam diameter of the laser beam of a predetermined wavelength oscillated from the laser beam generation part, and a control part for controlling the laser beam diameter by the polarization of the laser beam whose laser beam diameter is adjusted by the laser beam diameter adjustment part. A laser light branching unit that performs transmission and reflection, a laser light scanning unit that two dimensionally scans the laser light transmitted through the laser light branching unit, a laser light irradiation unit that irradiates a printing target with the laser light scanned by the laser light scanning unit, a laser light measurement unit that measures reflected light from the printing target, and a focus control unit that controls a laser light diameter adjustment unit by the laser light measurement unit, the focus control part controls a focus position of the laser beam emitted to the printing object by the laser beam irradiation part based on the shape of the laser beam of the reflected light measured by the laser beam measurement part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a printing device and a printing method. [Background technology]

[0002] Recently, laser markers (LMs) have become popular because they are highly minute, indestructible, and suitable for traceability. For example, Patent Document 1 describes a device that "includes a distance measurement pointer light emitter (460) that emits a pointer light toward the surface of a workpiece, an imaging unit (456) that has a light receiving axis branched from the emission axis of the laser beam and captures an image of a bright spot created on the workpiece surface when the pointer light hits it, a memory that records distance derivation information for deriving the working distance, and working distance measurement means that calculates the working distance based on the distance derivation information in the memory and the position of the bright spot in the image captured by the imaging unit." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-036841 Summary of the Invention [Problem to be solved by the invention]

[0004] In order to achieve high visibility and high-speed printing with a laser marker, it is necessary to increase the output of the laser that serves as the light source, but this creates problems such as larger equipment, higher costs, and a shorter lifespan. Therefore, rather than simply increasing the laser power, it is important to effectively utilize the laser power energy within a range appropriate for the object to be printed, thereby suppressing these problems and achieving both high visibility and high-speed printing without print smearing.

[0005] While high visibility can be achieved by printing with energy appropriate for the object to be printed, unless the position of the laser beam spot is detected and the position of the laser beam spot is appropriately controlled, visibility will be reduced. To avoid this problem, focus control can be performed by measuring the position of the beam spot using a distance sensor that measures the distance from the object to be printed. However, adding a new distance sensor is not necessarily an appropriate method due to the increased size and cost of the device mentioned above.

[0006] Furthermore, in order to perform appropriate focus control on a variety of printing targets, including not only flat surfaces but also curved surfaces and three-dimensional shapes, there is a limit to the accuracy of visibility when simply measuring the position of the laser beam spot indirectly using a distance sensor. Therefore, in order to achieve high visibility on a variety of printing targets, it is desirable to measure the position of the beam spot directly by measuring the shape of the laser beam spot. In addition, by quickly performing focus control on the printing target, it is possible to achieve both the high visibility and high-speed printing described above.

[0007] Prior art, including Patent Document 1, does not address this issue, and there has been a demand for technology that can achieve both high visibility and high-speed printing without increasing the size, cost, or lifespan of the device.

[0008] The present invention aims to provide a printing device and a printing method that can achieve high visibility and high-speed printing without increasing the size, cost, or life of the device. [Means for solving the problem]

[0009] a laser beam diameter adjusting unit that adjusts the beam diameter of the laser beam having a predetermined wavelength emitted from the laser beam generating unit; a laser beam branching unit that transmits and reflects the laser beam by polarization, the laser beam diameter of which has been adjusted by the laser beam diameter adjusting unit; a laser beam scanning unit that two-dimensionally scans the laser beam that has passed through the laser beam branching unit; a laser beam irradiating unit that irradiates the laser beam scanned by the laser beam scanning unit onto the object to be printed; a laser beam measuring unit that measures the light reflected from the object to be printed; and a focus control unit that controls the laser beam diameter adjusting unit using the laser beam measuring unit, wherein the focus control unit controls the focus position of the laser beam irradiated onto the object to be printed by the laser beam irradiating unit based on the shape of the laser beam of the reflected light measured by the laser beam measuring unit. [Effects of the Invention]

[0010] According to the present invention, high visibility and high-speed printing can be achieved without increasing the size, cost, or life of the device. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a diagram illustrating an example of a functional configuration of a laser marker according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the physical configuration of the laser marker illustrated in FIG. [Figure 3] 10 is a flowchart showing an example of a processing procedure for marking processing in which a laser beam shape is measured and laser marking is performed in the present embodiment. [Figure 4] FIG. 10 is a diagram illustrating an example of a functional configuration of a laser marker according to a second embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the physical configuration of the laser marker illustrated in FIG. 4. [Figure 6] 10A and 10B are diagrams for explaining how a center-of-gravity position measuring sensor measures the center-of-gravity position of laser light; [Figure 7] 10 is a flowchart showing an example of a processing procedure for marking processing in which a laser beam shape is measured and laser marking is performed in the present embodiment. [Figure 8] 10 is a flowchart showing another example of the processing procedure of the marking process for measuring the laser beam shape and performing laser marking in the present embodiment. [Figure 9] FIG. 10 is a diagram illustrating an example of the functional configuration of a laser marker according to a third embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of the physical configuration of the laser marker illustrated in FIG. 9. [Figure 11] 10 is a flowchart showing an example of a processing procedure for marking processing in which a laser beam shape is measured and laser marking is performed in the present embodiment. [Figure 12] 10 is a flowchart showing another example of the processing procedure of the marking process for measuring the laser beam shape and performing laser marking in the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The examples are illustrative for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc. disclosed in the drawings.

[0013] In addition, when there are multiple components having the same or similar functions, they may be described by using the same reference numeral with different subscripts, or when there is no need to distinguish between these multiple components, the subscripts may be omitted.

[0014] In the embodiments, processing performed by executing a program may be described. Here, a computer executes the program using a processor (e.g., a CPU or a GPU) and performs processing defined by the program using storage resources (e.g., a memory) and interface devices (e.g., a communication port). Therefore, the entity performing the processing by executing the program may be the processor. Similarly, the entity performing the processing by executing the program may be a controller, device, system, computer, or node having a processor. The entity performing the processing by executing the program may be any computing unit, and may include a dedicated circuit that performs specific processing. Here, the dedicated circuit may be, for example, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or a CPLD (Complex Programmable Logic Device).

[0015] A program may be installed on a computer from a program source. The program source may be, for example, a program distribution server or a computer-readable storage medium. When the program source is a program distribution server, the program distribution server may include a processor and a storage resource for storing the program to be distributed, and the processor of the program distribution server may distribute the program to be distributed to other computers. In addition, in an embodiment, two or more programs may be realized as one program, or one program may be realized as two or more programs. Example 1 FIG. 1 is a diagram showing an example of the functional configuration of a laser marker 1000 in Example 1. The laser marker 1000 is a device capable of printing any pattern by irradiating a laser beam of a predetermined wavelength onto the surface of an object to be printed. As shown in FIG. 1, the laser marker 1000 includes a print pattern input unit 10 that receives input of a print pattern to be printed on the object to be printed (e.g., the number "0" that constitutes part of a manufacturing number), a print coordinate generation unit 11 that generates coordinates on the object to be printed 7 of the print pattern input by the print pattern input unit 10, a print control unit 12 that controls each unit of the laser marker 1000, a laser beam generation unit 1 that oscillates a laser beam of a predetermined wavelength, a laser beam diameter adjustment unit 2 that adjusts the beam diameter of the laser beam of the predetermined wavelength oscillated from the laser beam generation unit 1, and a laser beam The laser beam splitter 3 transmits and reflects the beam whose diameter has been adjusted by the diameter adjustment unit 2 using polarization; a laser beam scanning unit 4 and a laser beam scanning unit 5 which two-dimensionally scan the beam that has passed through the laser beam splitter 3; a laser beam irradiation unit 6 which irradiates the beam scanned by the laser beam scanning unit 4 and the laser beam scanning unit 5 onto an object to be printed 7; a laser beam measuring unit 8 which measures the light reflected from the object to be printed 7; and a focus control unit 9 which performs focus control such as controlling the focal position based on the laser beam shape of the reflected light obtained from the signal measured by the laser beam measuring unit 8.

[0016] 2 is a diagram showing an example of the physical configuration of the laser marker 1000 shown in FIG. 2. As shown in FIG. 2, the laser marker 1000 physically includes a laser light source 1a operating as a laser light generating unit 1, a beam expander 2a operating as a laser beam diameter adjusting unit 2, a beam splitter 3a and a quarter-wave plate 3b operating as a laser beam branching unit 3, an X mirror 4a and a Y mirror 4b operating as a laser beam scanning unit 4 and a laser beam scanning unit 5, which are driven as galvanometer mirrors of a galvanometer scanner, an fθ lens 6a for focusing which operates as a laser beam irradiating unit 6, an imaging lens 8a and a line sensor 8b for measuring the shape of the laser beam which operate as a laser beam measuring unit 8, and a measurement error generating circuit 9a operating as a focus control unit 9. The X mirror 4a is scanned in the X-axis direction shown in FIG. 2, and the Y mirror 4b is scanned in the Y-axis direction shown in FIG. 2. The print pattern input unit 10, print coordinate generation unit 11, and print control unit 12 can be realized by a general computer having a processor and memory executing a program.

[0017] In FIG. 2, the laser beam L1 emitted from the laser source 1a has its laser beam diameter (e.g., spot size and divergence angle) adjusted by the beam expander 2a. The adjusted laser beam L1 is then reflected by an X mirror 4a and a Y mirror 4b for scanning the laser beam L1 and enters a focusing fθ lens 6a for focusing the laser beam. The laser beam is then focused at a laser beam spot position P1 on the object to be marked, which is placed at the focal position of the focusing fθ lens 6a, thereby marking the object to be marked 7. Reflected light L2 from the laser beam spot position P1 passes through a quarter-wave plate 3b and a beam splitter 3a and is detected by the line sensor 8b. For example, the line sensor 8b measures a Gaussian laser beam shape F1 as the detected reflected light L2. Here, a case where the laser beam shape is Gaussian is illustrated as an example, but other laser beam shapes, such as a top-hat shape or a ring shape, may also be measured.

[0018] Then, from the measurement results, the measurement error generating circuit 9a calculates the amount of deviation from the desired laser beam shape and center of gravity position, and adjusts the divergence angle of the beam expander 2a according to the amount of deviation. By this control, the laser beam shape and laser beam spot position can be directly controlled.

[0019] Typically, laser markers are designed to produce clear printing at the exact focus position. Therefore, as the focus deviates from this position, the spot broadens, the energy density decreases, and the printing becomes faint. To avoid this problem, conventional technology has used a newly installed distance sensor to measure the distance to the target object, thereby indirectly adjusting the laser beam spot position. However, this method of pseudo-measuring the laser beam spot position using a distance sensor does not necessarily allow for accurate adjustment of the laser beam shape or laser beam spot position, making it difficult to achieve high-precision focus control. According to this embodiment, the laser beam shape and laser beam spot position can be quickly changed by directly monitoring them without using the distance sensor described above. This enables unprecedented high-precision focus control on the target object 7, improving printing speed with good visibility.

[0020] FIG. 3 is a flowchart showing an example of a procedure for marking processing in this embodiment, in which the laser beam shape is measured and laser marking is performed.

[0021] As shown in Fig. 3, the print pattern input unit 10 accepts a print pattern input by a user (S101). A general computer having an interface such as a touch panel can be used as the print pattern input unit 10. The print pattern input unit 10 does not necessarily have to be provided in the laser marker 1000, and the laser marker 1000 may receive the print pattern from the print pattern input unit 10. The print pattern includes various identification information to be printed on the print target, such as numbers such as "0" and "1" and alphabetic characters such as "A" and "B," as well as various information that can be marked by a laser marker.

[0022] The print coordinate generation unit 11 generates coordinates (x, y) for printing the print pattern input in S101 (S102). As with the print pattern input unit 10, a general computer can be used as the print coordinate generation unit 11. The coordinates are, for example, information representing the positions of the lines that make up the print pattern on the plane of the print target 7.

[0023] The print control unit 12 scans the laser light scanning unit 4 and the laser light scanning unit 5 so that the position of the coordinates (x, y) generated in S102 becomes the laser light spot position P1, and prints the print pattern on the print target 7 (S103).

[0024] When a print pattern is printed on the print target 7, reflected light L2 from laser beam spot position P1 passes through the focusing fθ lens 6a, X mirror 4a and Y mirror 4b, ¼ wavelength plate 3b, and beam splitter 3a and reaches line sensor 8b. Line sensor 8b detects the reflected light L2, and print control unit 12 measures the laser beam shape from the brightness of the detected reflected light L2. Then, print control unit 12 calculates the center of gravity position on line sensor 8b for the identified laser beam shape, and compares the calculated center of gravity position on line sensor 8b with the center of gravity position of a predetermined desired laser beam shape (S104).

[0025] The print control unit 12 determines whether the calculated center of gravity position on the line sensor 8b satisfies a predetermined condition with respect to the center of gravity position of the desired laser beam shape (S105). For example, the print control unit 12 determines whether the calculated center of gravity position on the line sensor 8b is within a range of ±5% with respect to the center of gravity position of the desired laser beam shape.

[0026] If the printing control unit 12 determines that the calculated center of gravity position on the line sensor 8b is within a range of ±5% of the center of gravity position of the desired laser light shape (S105; Yes), it maintains the position of the divergence angle adjustment element of the beam expander 2a (S106) and proceeds to S108.

[0027] On the other hand, if the print control unit 12 determines that the calculated center of gravity position on the line sensor 8b is not within a range of ±5% of the center of gravity position of the desired laser beam shape (S105; No), it instructs the measurement error generation circuit 9a to change the position of the divergence angle adjustment element of the beam expander 2a. The measurement error generation circuit 9a changes the position of the divergence angle adjustment element of the beam expander 2a in accordance with the instruction (S107). Thereafter, the process returns to step S105, and the measurement error generation circuit 9a performs control to change the position of the divergence angle adjustment element so that it is within the above range.

[0028] When the printing control unit 12 executes S106, it determines whether printing has been completed for all coordinates (x, y) generated in S102 (S108), and if it determines that printing has been completed for all coordinates (x, y) generated in S102 (S108; Yes), it terminates this processing.

[0029] On the other hand, when the printing control unit 12 executes S106, if it determines that printing has not been performed for all of the coordinates (x, y) generated in S102 (S108; No), it returns to S103 and repeats the subsequent processing until printing has been performed for all of the coordinates (x, y).

[0030] As described above, according to the laser marker 1000 of this embodiment, focus control is performed based on the laser beam shape of the reflected light L2, so that high visibility and high-speed printing can be achieved simultaneously without increasing the size, cost, or lifespan of the device. Example 2 In Example 1, high visibility and high-speed printing were achieved by directly controlling focus based on the laser beam shape of the reflected light obtained from the laser beam spot position. When performing laser marking, since the laser beam is invisible, the laser beam spot position and laser beam intensity must be adjusted while marking the target object. To facilitate accurate and easy adjustment, a spot monitor function for monitoring the laser beam spot position and laser beam intensity is further provided. This configuration allows time-series data on defocused printing and printing power to be acquired, and these data can be used as command values ​​for a beam expander to expand the spot diameter of the laser beam spot. As a result, a single laser marker can monitor the laser beam spot position and laser beam intensity for laser beams of various shapes, reducing implementation costs and enabling high-speed printing while understanding the recording status and preventing print distortion.

[0031] 4 is a diagram showing an example of the functional configuration of a laser marker 2000 in Example 2. Like the laser marker 1000 in Example 1, the laser marker 2000 is a device that is capable of printing any pattern by irradiating a laser beam of a predetermined wavelength onto the surface of an object to be printed. In the following, the same components as those of the laser marker 1000 in Example 1 are given the same reference numerals and their description will be omitted, and the configuration that differs from the laser marker 1000 will be mainly described.

[0032] 4, the laser marker 2000 has the same components as the laser marker 1000 in Example 1: a laser beam generating unit 1, a laser beam diameter adjusting unit 2, a laser beam branching unit 3, a laser beam scanning unit 4 and a laser beam scanning unit 5, a laser beam irradiating unit 6, and a print control unit 12; and a laser beam measuring unit 80 and a focus control unit 90, which are different from those of the laser marker 1000 in Example 1. The laser beam measuring unit 80 is, for example, a sensor for measuring the laser beam shape and center of gravity position of the reflected beam. The focus control unit 90 is, for example, a circuit for performing focus control, such as controlling the focal position, based on the laser beam shape and center of gravity position of the reflected beam measured by the laser beam measuring unit 80.

[0033] Fig. 5 is a diagram showing an example of the physical configuration of the laser marker 2000 shown in Fig. 4. As shown in Fig. 5, similarly to the laser marker 1000 in Example 1, the laser marker 2000 physically includes a laser light source 1a, a beam expander 2a, a beam splitter 3a, a quarter-wave plate 3b, an X mirror 4a, a Y mirror 4b, and an fθ lens 6a for focusing.

[0034] The laser marker 2000 also includes an imaging lens 80a and line sensor 80b for measuring the shape of the laser beam, an imaging lens 80c and center-of-gravity position measurement sensor 80d for measuring the center-of-gravity position, and a half beam splitter 80e for splitting the light reflected from the laser beam spot position, all of which function as the laser beam measurement unit 80. The laser marker 2000 also includes a measurement error generation circuit 90a for adjusting the laser beam spot position and the intensity of the laser beam using signals output from the line sensor 80b and the center-of-gravity position measurement sensor 80d. The center-of-gravity position measurement sensor 80d can be an OEIC (Optoelectronic Integrated Circuit) or various cameras.

[0035] In FIG. 5, similar to the first embodiment, laser light L1 adjusted by the beam expander 2a is reflected by the X mirror 4a and the Y mirror 4b, passes through the focusing fθ lens 6a, and is then marked on the printing target 7. Thereafter, reflected light L2 from the laser light spot position P1 passes through the quarter-wave plate 3b and the beam splitter 3a and is input to the laser light measuring unit 80. The input reflected light L2 is split by the half beam splitter 80e of the laser light measuring unit 80. As in the first embodiment, one of the split reflected light beams passes through the imaging lens 80a and is input to the line sensor 80b, where the laser light shape of the reflected light L2 is measured. For example, as in the first embodiment, the line sensor 80b measures a Gaussian laser light shape F1 as the reflected light L2.

[0036] On the other hand, the other branched reflected light passes through an imaging lens 80c and enters a barycenter position measuring sensor 80d, whereby the barycenter position of the reflected light L2 is measured.

[0037] 6 is a diagram for explaining how the center-of-gravity position measuring sensor 80d measures the center-of-gravity position of laser light. Here, a case where the center-of-gravity position measuring sensor 80d is an OEIC will be explained.

[0038] As shown in Figure 6, the output signal of the OEIC constituting the center-of-gravity position measuring sensor 80d is classified into three patterns depending on the positional relationship between the beam spot and the object to be printed. For example, it can be classified into (a) a pattern in which the beam spot is formed in front of the object to be printed, (b) a pattern in which the beam spot is formed on the object to be printed, and (c) a pattern in which the beam spot is formed behind the object to be printed. In this example, in (a), a signal is output in which the difference in signal levels added in the diagonal direction is negative, in (b) the difference is zero, and in (c) the difference is positive.

[0039] In this way, the center of gravity position of the beam spot can be directly measured by the center of gravity position measuring sensor 80d. While an OEIC is used in this example, the same applies when various cameras are used. In this case, the image is divided into four pseudo-areas, and the difference in signal level between the diagonal areas of each divided area is calculated to determine which of the above patterns (a) to (c) applies.

[0040] When the line sensor 80b measures the laser beam shape of the reflected light L2 and the center-of-gravity position measuring sensor 80d measures the center-of-gravity position of the laser beam, the measurement error generating circuit 90a calculates the amount of deviation from the desired laser beam shape and center-of-gravity position from these results and adjusts the divergence angle of the beam expander 2a according to the deviation. This control allows the spot diameter and shape of the laser beam to be quickly and accurately changed, making it possible to print, for example, on the printing object 7 with a desired print thickness equivalent to that of a mark made by multiple laser beams. As a result, printing speed can be improved while maintaining good visibility.

[0041] Fig. 7 is a flowchart showing an example of the process procedure for marking in this embodiment, in which the laser beam shape is measured and laser marking is performed. Since the processes from S201 to S203 in Fig. 7 are the same as the processes from S101 to S103 in the first embodiment, their description will be omitted here, and only the process from S204 onwards will be described.

[0042] As shown in FIG. 7, in S203, when the print pattern is printed on the print target 7, the position of the divergence angle adjustment element of the beam expander 2a is changed according to the amount of deviation of the center of gravity detected by the center of gravity position measurement sensor 80d. For example, the print control unit 12 instructs the measurement error generation circuit 90a to adjust the position of the divergence angle adjustment element of the beam expander 2a so that the center of gravity of the beam spot becomes pattern (b) shown in FIG. 6 (i.e., the value of the OEIC output signal is ±0). The measurement error generation circuit 90a adjusts the position of the divergence angle adjustment element of the beam expander 2a in accordance with the instruction. The print control unit 12 compares the center of gravity of a predetermined desired laser beam shape with the center of gravity position detected by the center of gravity position measurement sensor 80d (S204).

[0043] The print control unit 12 determines whether the center of gravity position detected by the center of gravity position measuring sensor 80d satisfies a predetermined condition with respect to the center of gravity position of the desired laser beam shape (S205). For example, the print control unit 12 determines whether the center of gravity position detected by the center of gravity position measuring sensor 80d is within a range of ±5% with respect to the center of gravity position of the desired laser beam shape.

[0044] If the print control unit 12 determines that the center of gravity position detected by the center of gravity position measuring sensor 80d is within a range of ±5% of the center of gravity position of the desired laser beam shape (S205; Yes), the print control unit 12 identifies the laser beam shape from the brightness of the reflected light L2 detected by the line sensor 80b, as in Example 1. Furthermore, the print control unit 12 calculates the difference in similarity between the identified laser beam shape and the desired laser beam shape (S206).

[0045] The print control unit 12 determines whether the difference in similarity between the specified laser beam shape and the desired laser beam shape satisfies a predetermined condition (S207). For example, the print control unit 12 determines whether the difference in similarity between the two is within a range of ±5%.

[0046] If the printing control unit 12 determines that the difference in similarity between the identified laser light shape and the desired laser light shape is within the range of ±5% (S207; Yes), it maintains the position of the divergence angle adjustment element of the beam expander 2a (S208) and proceeds to S209.

[0047] On the other hand, if the print control unit 12 determines that the difference in similarity between the identified laser beam shape and the desired laser beam shape is not within ±5% (S207; No), it instructs the measurement error generation circuit 90a to change the position of the divergence angle adjustment element of the beam expander 2a. The measurement error generation circuit 90a fine-tunes the position of the divergence angle adjustment element of the beam expander 2a in accordance with the instruction (S209). Thereafter, the process returns to step S206, and the measurement error generation circuit 90a controls to change the position of the divergence angle adjustment element so that it is within the above range.

[0048] When the printing control unit 12 executes S208, it determines whether printing has been completed for all coordinates (x, y) generated in S202 (S210), and if it determines that printing has been completed for all coordinates (x, y) generated in S202 (S210; Yes), it terminates this processing.

[0049] On the other hand, if the printing control unit 12 determines that printing has not been performed for all of the coordinates (x, y) generated in S102 (S210; No), it returns to S203 and repeats the subsequent processing until printing has been performed for all of the coordinates (x, y).

[0050] As shown in Fig. 8, the process shown in Fig. 7 may return to S204 and perform the subsequent processes without performing step S209. In Fig. 8, if the print control unit 12 determines that the difference in similarity between the specified laser beam shape and the desired laser beam shape is not within the range of ±5% (S207; No), the process returns to S204 and performs the subsequent processes. By such control, when the difference in similarity between the specified laser beam shape and the desired laser beam shape is not within the range of ±5%, the position of the divergence angle adjustment element of the beam expander 2a can be immediately changed taking into account the deviation amount of the center of gravity position, and the marking process can be performed more quickly.

[0051] As described above, according to the laser marker 2000 of this embodiment, focus control is performed based on the beam spot of reflected light L2 and the laser light shape, so the laser light spot position and laser light intensity can be automatically adjusted, reducing the operational burden and achieving both high visibility and high-speed printing without increasing the size, cost, or lifespan of the device.

[0052] Methods for achieving high-speed printing by increasing the printing speed of a laser marker include mechanically increasing the printing speed by increasing the speed of the galvanometer mirror through improvements to the motor, and optically increasing the printing speed by enlarging the beam spot diameter of the laser beam. The former method relies on the performance of the motor, which leads to an increase in the size and cost of the device, so the latter method is preferable. However, even in the latter case, if the printing width is wider than the beam spot diameter, it is necessary to increase the speed of the galvanometer mirror and print multiple lines with the laser beam, which again does not solve the problems of high cost and short life mentioned above.

[0053] However, according to this embodiment, the laser beam shape and the laser beam spot position can be directly monitored by the above-mentioned spot monitor function without using a distance sensor as in the conventional technology, thereby making it possible to quickly change the laser beam shape and the laser beam spot position, and by monitoring beams shaped in accordance with the relationship between the print width and the beam spot diameter, such as not only Gaussian but also top hat and ring shapes, it is possible to achieve both high visibility and high speed printing without printing with a laser beam of multiple lines. In other words, to achieve both high visibility and high speed printing, it is necessary to increase the output of the laser beam that serves as the light source, which would result in an increase in the size, cost, and life of the device. However, by shaping the light intensity of the laser beam and changing it from a Gaussian shape to another laser beam shape, it is possible to reduce the required laser power, thereby making it possible to reduce the size and cost of the device. Example 3 In the second embodiment, the laser beam shape F1 detected by the line sensor is detected, and the center of gravity position of the laser beam is measured, thereby making it possible to adjust the laser beam spot position and the intensity of the laser beam, and the beam is shaped not only into a Gaussian shape but also into a top hat shape, ring shape, etc., depending on the relationship between the print width and the beam spot diameter. Below, a case will be described in which a beam of these laser beam shapes is shaped and output, and these laser beam shapes are detected and the center of gravity position is measured.

[0054] 9 is a diagram showing an example of the functional configuration of a laser marker 3000 in Example 3. Like the laser markers 1000 and 2000 in Examples 1 and 2, the laser marker 3000 is a device that is capable of printing any pattern by irradiating a laser beam of a predetermined wavelength onto the surface of an object to be printed. In the following, the same components as those of the laser markers 1000 and 2000 in Examples 1 and 2 are given the same reference numerals and their description will be omitted, and the configuration that differs from the laser marker 1000 will be mainly described.

[0055] 9, the laser marker 3000 has the same components as the laser markers 1000 and 2000 in Examples 1 and 2: a laser beam generating unit 1, a laser beam diameter adjusting unit 2, a laser beam branching unit 3, a laser beam scanning unit 4 and a laser beam scanning unit 5, a laser beam irradiating unit 6, and a print control unit 12, as well as a laser beam measuring unit 80 and a focus control unit 90, as in the laser marker in Example 2. Furthermore, in this example, the laser marker 3000 has a laser beam shaping unit 13 for shaping the laser beam that has passed through the laser beam diameter adjusting unit 2 in which the position of the divergence angle adjustment element has been adjusted.

[0056] FIG. 10 is a diagram showing an example of the physical configuration of the laser marker 3000 shown in FIG. 9 . As shown in FIG. 10 , the laser marker 3000 physically includes a laser light source 1a, a beam expander 2a, a beam splitter 3a, a quarter-wave plate 3b, an X mirror 4a, a Y mirror 4b, and an fθ lens 6a for focusing, similar to the laser markers 1000 and 2000 in Examples 1 and 2. The laser marker 3000 also includes a laser beam shaping element 13a. The laser beam shaping element 13a may be a DOE (Diffractive Optical Element) or an ROE (Refractive Optical Element). The laser beam shaping element 13a shapes the laser beam L1 emitted from the laser light source 1a into a laser beam shape such as a Gaussian shape, a top-hat shape, or a ring shape. The physical configurations of the laser beam measuring unit 80 and the focus control unit 90 are the same as those in the second embodiment, and therefore will not be described here.

[0057] 10, the laser beam having the laser beam shape shaped by the laser beam shape shaping element 13a passes through the beam splitter 3a and is then detected by the line sensor 80b as the laser beam shape of the reflected beam L2. For example, the line sensor 80b detects, as the reflected beam L2, not only the Gaussian laser beam shape F1 but also other types of laser beam shapes shaped by the laser beam shape shaping element 13a. In this example, in addition to the Gaussian laser beam shape F1, the line sensor 80b detects a top-hat laser beam shape F2 and a ring-shaped laser beam shape F3.

[0058] Fig. 11 is a flowchart showing an example of the process procedure for marking in this embodiment by measuring the laser beam shape. Since the processes from S301 to S305 in Fig. 11 are the same as the processes from S201 to S205 in Fig. 7, their description will be omitted here, and only the process from S306 onwards will be described.

[0059] As shown in FIG. 11, if the print control unit 12 determines in S305 that the center of gravity position detected by the center of gravity position measurement sensor 80d is within a ±5% range of the center of gravity position of the desired laser beam shape (S305; Yes), it calculates the least square error for the laser beam shape of the brightness detected by the line sensor 80b, and outputs the result of fitting the laser beam shape with a predetermined function using the minimum square error. Furthermore, it calculates the least square error for a predetermined desired laser beam shape, and outputs the result of fitting the laser beam shape with a predetermined function using the minimum square error. Then, the print control unit 12 calculates the error of these output results (S306). The predetermined desired laser beam shape is, for example, a Gaussian, top hat, or ring laser beam shape, as shown in Example 2.

[0060] The printing control unit 12 determines whether the error calculated in S305 is within the range of ±5% (S307), and if it determines that the error calculated in S305 is within the range of ±5% (S307; Yes), it maintains the position of the divergence angle adjustment element of the beam expander 2a (S308) and proceeds to S310.

[0061] On the other hand, if the print control unit 12 determines that the error calculated in S305 is not within the range of ±5% (S307; No), it instructs the measurement error generation circuit 90a to change the position of the divergence angle adjustment element of the beam expander 2a. The measurement error generation circuit 90a fine-tunes the position of the divergence angle adjustment element of the beam expander 2a in accordance with the instruction (S309). Thereafter, the process returns to step S307, and the measurement error generation circuit 90a performs control to change the position of the divergence angle adjustment element so that it is within the above range.

[0062] When the printing control unit 12 executes S308, it determines whether printing has been completed for all coordinates (x, y) generated in S302 (S310), and if it determines that printing has been completed for all coordinates (x, y) generated in S302 (S310; Yes), it terminates this processing.

[0063] On the other hand, if the printing control unit 12 determines that printing has not been performed for all of the coordinates (x, y) generated in S302 (S310; No), it returns to S303 and repeats the subsequent processing until printing has been performed for all of the coordinates (x, y).

[0064] As shown in Fig. 12, the process shown in Fig. 11 may return to S304 and perform the subsequent processes without performing step S309. In Fig. 12, if the print control unit 12 determines that the error calculated in S305 is not within the range of ±5% (S307; No), the process returns to S304 and performs the subsequent processes. With this control, if the error calculated in S305 is not within the range of ±5%, the position of the divergence angle adjustment element of the beam expander 2a can be immediately changed taking into account the deviation amount of the center of gravity position, and the marking process can be performed more quickly.

[0065] As described above, according to the laser marker 3000 of this embodiment, focus control is performed based on the error between the laser beam shape of the reflected light L2, which has been shaped by the laser beam shape shaping element 13a into various laser beam shapes such as Gaussian, top hat, and ring, and these predetermined desired laser beam shapes, so that the laser beam spot position and laser beam intensity can be automatically adjusted according to each type of laser beam shape, reducing the operational burden and achieving both high visibility and high-speed printing without incurring increases in the size, cost, or lifespan of the device.

[0066] As described above, the laser marker 1000 according to the first embodiment is a printing device (e.g., laser marker 1000) that can print any pattern by irradiating a laser beam onto a surface of a printing object (e.g., printing object 7), as described with reference to FIGS. 1-3 and the like, and includes a laser beam generating unit (e.g., laser beam generating unit 1) that oscillates laser beam, a laser beam diameter adjusting unit (e.g., laser beam diameter adjusting unit 2) that adjusts the beam diameter of the laser beam of a predetermined wavelength oscillated from the laser beam generating unit, a laser beam branching unit (e.g., laser beam branching unit 3) that transmits and reflects the laser beam whose diameter has been adjusted by the laser beam diameter adjusting unit, and The laser beam scanning device includes a laser beam scanning unit (e.g., laser beam scanning units 4 and 5) that two-dimensionally scans the laser beam that has passed through a laser beam branching unit, a laser beam irradiating unit (e.g., laser beam irradiating unit 6) that irradiates the laser beam scanned by the laser beam scanning unit onto the object to be printed, a laser beam measuring unit (e.g., laser beam measuring unit 8) that measures the light reflected from the object to be printed, and a focus control unit (e.g., focus control unit 8) that controls the laser beam diameter adjustment unit using the laser beam measuring unit, and the focus control unit controls the focal position of the laser beam irradiated onto the object to be printed by the laser beam irradiating unit based on the shape of the laser beam of the reflected light measured by the laser beam measuring unit. As a result, focus control is performed based on the laser beam shape of the reflected light, and therefore high visibility and high-speed printing can be achieved simultaneously without increasing the size, cost, or life of the device.

[0067] As described with reference to Figures 4-8 and other figures, the laser marker 2000 according to the second embodiment includes a laser beam shape measurement unit that measures the shape of the laser beam using the laser beam branching unit, and a center of gravity position measurement unit that measures the center of gravity of the laser beam (e.g., laser beam measurement unit 80, laser beam shape measurement imaging lens 80a, line sensor 80b, center of gravity position measurement imaging lens 80c, center of gravity position measurement sensor 80d, and half beam splitter 80e). Based on the laser beam shape measurement unit and the center of gravity position measurement unit, the focus control unit controls the divergence angle of the laser beam from the laser beam diameter adjustment unit, and the laser beam irradiation unit controls the focal position of the laser beam irradiated onto the target object. This allows focus control based on the beam spot of the reflected light and the laser beam shape, so that the laser beam spot position and the laser beam intensity can be automatically adjusted. As a result, high visibility and high-speed printing can be achieved simultaneously, while reducing the operational burden and avoiding increases in the size, cost, and lifespan of the device.

[0068] As described with reference to Figures 9-12 and other figures, the laser marker 3000 according to the third embodiment includes a laser beam shaping unit (e.g., laser beam shaping unit 13) that shapes and adjusts the shape of the laser beam whose diameter has been adjusted by the laser beam diameter adjustment unit. The focus control unit controls the divergence angle of the laser beam from the laser beam diameter adjustment unit based on the laser beam shape measurement unit and the center of gravity position measurement unit, and the laser beam irradiation unit controls the focal position of the laser beam irradiated onto the target object. This allows focus control based on the error between the laser beam shapes of the reflected light of various shaped laser beams and the predetermined desired laser beam shapes, thereby automatically adjusting the laser beam spot position and laser beam intensity according to each type of laser beam shape. As a result, high visibility and high-speed printing can be achieved simultaneously, while reducing the operational burden and avoiding increases in the size, cost, and lifespan of the device.

[0069] The present invention is not limited to the above-described embodiments as they are, and in the implementation stage, the components can be modified and embodied within the scope of the gist of the present invention, or multiple components disclosed in the above-described embodiments can be appropriately combined. [Explanation of symbols]

[0070] 1 Laser light generating unit 2 Laser beam diameter adjustment unit 3 Laser beam branching section 4. Laser beam scanning unit (x) 5. Laser beam scanning unit (y) 6 Laser light irradiation unit 7 Printing target 8, 80 Laser measurement unit 9, 90 Focus control unit 10 Printing pattern input section 11 Print coordinate generation unit 12 Printing control unit 13 Laser beam shaping section 1a Laser light source 2a Beam Expander 3a Beam splitter 3b 1 / 4 wave plate 4a X mirror for laser beam scanning 5a Y mirror for laser beam scanning 6a fθ lens for focusing laser light 80a Imaging lens for laser beam shape measurement 80b line sensor 80c Imaging lens for measuring center of gravity position 80d Center of gravity position measurement sensor 80e Half Beam Splitter 13a Beam shaping element L1 laser light L2 reflected light P1 Laser light spot position

Claims

1. A printing device capable of printing any pattern by irradiating a printing surface of a printing object with laser light, a laser light generating unit that oscillates a laser light; a laser beam diameter adjusting unit that adjusts the beam diameter of the laser beam having a predetermined wavelength oscillated from the laser beam generating unit; a laser beam branching unit that transmits and reflects the laser beam whose diameter has been adjusted by the laser beam diameter adjusting unit according to polarization; a laser beam scanning unit that two-dimensionally scans the laser beam that has passed through the laser beam branching unit; a laser light irradiation unit that irradiates a printing target with the laser light scanned by the laser light scanning unit; a laser light measuring unit that measures reflected light from the printing object; a focus control unit that controls the laser beam diameter adjustment unit using the laser beam measurement unit, the focus control unit controls a focus position of the laser light irradiated onto the printing object by the laser light irradiating unit based on the shape of the reflected laser light measured by the laser light measuring unit. A printing device characterized by:

2. 2. The printing device according to claim 1, the laser beam shape measured by the laser beam measuring unit is any one of a Gaussian type, a ring type, and a top hat type; A printing device characterized by:

3. 2. The printing device according to claim 1, the laser beam measuring unit includes a laser beam shape measuring unit that measures a shape of the laser beam by the laser beam branching unit, and a center of gravity position measuring unit that measures a center of gravity position of the laser beam, a focus control unit that controls a divergence angle of the laser beam from the laser beam diameter adjustment unit based on the laser beam shape measurement unit and the center of gravity position measurement unit, and controls a focus position of the laser beam irradiated onto the printing object by the laser beam irradiation unit; A printing device characterized by:

4. 4. The printing device according to claim 3, the laser beam shape measured by the laser beam measuring unit is any one of a Gaussian type, a ring type, and a top hat type; A printing device characterized by:

5. 3. The printing device according to claim 2, a laser beam shaping unit that shapes and adjusts the shape of the laser beam whose diameter has been adjusted by the laser beam diameter adjusting unit; a focus control unit that controls a divergence angle of the laser beam from the laser beam diameter adjustment unit based on the laser beam shape measurement unit and the center of gravity position measurement unit, and controls a focus position of the laser beam irradiated onto the printing object by the laser beam irradiation unit; A printing device characterized by:

6. 4. The printing device according to claim 3, the laser beam shape measured by the laser beam measuring unit is any one of a Gaussian type, a ring type, and a top hat type; A printing device characterized by:

7. A printing method performed by a printing device capable of printing any pattern by irradiating a printing surface of a printing object with laser light, comprising: The laser light generating unit oscillates a laser light, a laser beam diameter adjusting unit that adjusts the beam diameter of the laser beam having a predetermined wavelength oscillated from the laser beam generating unit; a laser beam branching unit that transmits and reflects the laser beam whose diameter has been adjusted by the laser beam diameter adjusting unit according to the polarization of the laser beam; a laser beam scanning unit that two-dimensionally scans the laser beam that has passed through the laser beam branching unit; a laser light irradiation unit irradiating the laser light scanned by the laser light scanning unit onto the printing object; a laser light measuring unit that measures reflected light from the printing object; a focus control unit that controls the laser beam diameter adjustment unit using the laser beam measurement unit; the focus control unit controls a focus position of the laser light irradiated onto the printing object by the laser light irradiating unit based on the shape of the reflected laser light measured by the laser light measuring unit. A printing method characterized by:

8. 8. The printing method according to claim 7, the laser beam measuring unit includes a laser beam shape measuring unit that measures a shape of the laser beam by the laser beam branching unit, and a center of gravity position measuring unit that measures a center of gravity position of the laser beam, a focus control unit that controls a divergence angle of the laser beam from the laser beam diameter adjustment unit based on the laser beam shape measurement unit and the center of gravity position measurement unit, and controls a focus position of the laser beam irradiated onto the printing object by the laser beam irradiation unit; A printing method characterized by:

9. 9. The printing method according to claim 8, a laser beam shaping unit that shapes and adjusts the shape of the laser beam whose diameter has been adjusted by the laser beam diameter adjusting unit; a focus control unit that controls a divergence angle of the laser beam from the laser beam diameter adjustment unit based on the laser beam shape measurement unit and the center of gravity position measurement unit, and controls a focus position of the laser beam irradiated onto the printing object by the laser beam irradiation unit; A printing method characterized by:

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