Focusing method of laser, focusing control device and laser etching equipment

Abstract

The invention discloses a focusing method of a laser, a focusing control device and laser etching equipment, and the focusing method of the laser comprises the steps: taking a current reference height as a starting point, and determining a plurality of different laser heights of the laser according to a current height adjustment step pitch; at each laser height, a laser device is controlled to form a plurality of light spots through laser etching, and the average diameter of the light spots corresponding to each laser height is determined; determining whether the laser height corresponding to the minimum light spot average diameter meets a preset focusing qualification condition or not; if not, the next reference height and the next height adjustment step pitch are determined according to the size relation of the light spot average diameters corresponding to the multiple different laser heights, and the steps are repeated till the laser height corresponding to the minimum light spot average diameter meets the preset focusing qualification condition. According to the technical scheme provided by the invention, laser focusing is accurately and efficiently completed, and the stability and improvement of the laser etching process quality are ensured.

Description

Technical Field

[0001] This invention relates to the field of laser technology, and more particularly to a laser focusing method, a focusing control device, and a laser engraving equipment. Background Technology

[0002] In the consumer electronics manufacturing industry, products such as mobile phones, computers, watches, and headphones typically require laser engraving equipment to permanently etch product information, such as serial numbers, model numbers, and certification marks, onto their casings, internal components, or specific marking areas before they leave the factory. This process demands that the laser-engraved patterns or text have a clear, consistent, and precise visual effect.

[0003] Currently, before laser engraving, the laser in the laser engraving equipment needs to be focused. A common method is to turn on the laser and test the brightness of the light produced when the laser strikes a metal sheet or material, thus determining if the laser is focused. This method has drawbacks. It relies entirely on the operator's ability to discern the brightness of the laser spot. Differences in visual sensitivity and experience among operators, as well as ambient light interference, can lead to inconsistent judgments of the "brightest" state, introducing human error. Furthermore, the human eye has limited ability to perceive minute changes in brightness, making it difficult to accurately pinpoint the focal point with the highest energy density. This can result in extremely unfavorable effects on fine laser engraving, such as light color and excessively wide line widths. Therefore, how to accurately and efficiently achieve laser focusing to ensure the stability and improvement of laser engraving quality has become a pressing technical problem. Summary of the Invention

[0004] One embodiment of the present invention provides a laser focusing method, a focusing control device, and a laser engraving equipment to accurately and efficiently complete laser focusing, thereby ensuring the stability and improvement of laser engraving process quality.

[0005] According to one aspect of the present invention, a method for focusing a laser is provided, comprising:

[0006] Determine the laser's current reference height and current height adjustment step size;

[0007] Starting from the current reference height, the step size is adjusted according to the current height to determine multiple different laser heights of the laser. The multiple different laser heights include at least the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height.

[0008] At each laser height, the laser is controlled to etch multiple light spots, and the average diameter of the light spot corresponding to each laser height is determined;

[0009] determine whether the laser height corresponding to the minimum spot average diameter satisfies a preset focus qualification condition;

[0010] In the case of not satisfying, according to the size relationship of the spot average diameters corresponding to the plurality of different laser heights, determine the next reference height and the next height adjustment step, and replace the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, repeat the above steps until the laser height corresponding to the minimum spot average diameter satisfies the preset focus qualification condition.

[0011] Optionally, the determining the next reference height and the next height adjustment step according to the size relationship of the spot average diameters corresponding to the plurality of different laser heights comprises:

[0012] In the case that the laser height corresponding to the minimum spot average diameter is the minimum value in the plurality of different laser heights, determine the current height adjustment step as the next height adjustment step, and determine the difference between the minimum value in the plurality of different laser heights and (n-1) / 2 times of the height adjustment step as the next reference height;

[0013] In the case that the laser height corresponding to the minimum spot average diameter is the maximum value in the plurality of different laser heights, determine the current height adjustment step as the next height adjustment step, and determine the sum of the maximum value in the plurality of different laser heights and (n-1) / 2 times of the height adjustment step as the next reference height;

[0014] In the case that the laser height corresponding to the minimum spot average diameter is neither the maximum value nor the minimum value in the plurality of different laser heights, determine the laser height corresponding to the minimum spot average diameter as the next reference height, and determine the ratio of the difference between the two laser heights adjacent to the laser height corresponding to the minimum spot average diameter and (n-1) as the next height adjustment step;

[0015] Wherein, n is an odd number greater than 3, and n is the number of the plurality of different laser heights.

[0016] Optionally, the determining the spot average diameter corresponding to each laser height comprises:

[0017] measuring the diameters of a plurality of spots engraved at each of the laser heights by an optical image measuring instrument;

[0018] calculating the average of the diameters of the plurality of spots at each of the laser heights to obtain the spot average diameter corresponding to each laser height.

[0019] Optionally, the determining whether the laser height corresponding to the minimum average diameter of the light spot meets the preset focus qualification condition comprises:

[0020] determining whether a difference between diameters of two adjacent light spots laser-engraved by the laser height corresponding to the minimum average diameter of the light spot is less than or equal to the maximum allowed deviation of the laser-engraved information line width;

[0021] if yes, it is determined that the laser height corresponding to the minimum average diameter of the light spot meets the preset focus qualification condition;

[0022] if no, it is determined that the laser height corresponding to the minimum average diameter of the light spot does not meet the preset focus qualification condition.

[0023] Optionally, the focus method of the laser further comprises:

[0024] determining the maximum allowed deviation of the laser-engraved information line width according to the maximum allowed line width of the laser-engraved information and the minimum allowed line width of the laser-engraved information.

[0025] Optionally, the focus method of the laser further comprises:

[0026] obtaining a focal length range of the laser;

[0027] determining an initial reference height and an initial height adjustment step distance of the laser according to the focal length range of the laser.

[0028] Optionally, the determining the initial reference height and the initial height adjustment step distance of the laser according to the focal length range of the laser comprises:

[0029] determining the initial reference height of the laser according to a middle value of the focal length range of the laser;

[0030] determining the initial height adjustment step distance according to the focal length range of the laser and a preset number of the plurality of different laser heights.

[0031] Optionally, the controlling the laser to laser-engrave a plurality of light spots at each of the laser heights comprises:

[0032] controlling the laser to laser-engrave a plurality of sequentially and spaced light spots on the same surface to be laser-engraved at each of the laser heights, so that the plurality of light spots laser-engraved at different laser heights form a light spot matrix on the same surface to be laser-engraved.

[0033] According to another aspect of the present application, there is provided a focus control device of a laser for performing the focus method of the laser according to any of the embodiments of the present application, comprising:

[0034] a height and step distance determining module for determining a current reference height and a current height adjustment step distance of the laser.

[0035] a laser height determining module, configured to determine a plurality of different laser heights of the laser according to the current height adjustment step distance, starting from the current reference height, wherein the plurality of different laser heights at least include the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height;

[0036] a control module, configured to control the laser to engrave a plurality of spots at each of the laser heights;

[0037] an average diameter determining module, configured to determine an average diameter of the spots corresponding to each of the laser heights;

[0038] a focusing judging module, configured to determine whether a laser height corresponding to a minimum average diameter of the spots meets a preset focusing qualification condition;

[0039] a height and step distance adjusting module, configured to, in the case of not meeting the preset focusing qualification condition, determine a next reference height and a next height adjustment step distance according to a size relationship of the average diameters of the spots corresponding to the plurality of different laser heights, and replace the current reference height and the current height adjustment step distance with the next reference height and the next height adjustment step distance respectively.

[0040] According to another aspect of the present application, there is provided a laser engraving device, comprising a laser and a focusing control device of the laser according to any of the embodiments of the present application.

[0041] The technical solution provided by one of the embodiments of the present application can find a laser height corresponding to a minimum average diameter of spots by engraving the spots at a plurality of different laser heights and measuring the diameters of the spots, and then find a plurality of laser heights again based on the laser height, until the difference between the diameters of two adjacent spots engraved by the laser height corresponding to the minimum average diameter of the spots meets a preset focusing qualification condition, so as to complete the laser focusing. By this method, the laser focusing condition can be reflected digitally, and the focal height of the laser can be positioned accurately according to the product requirement, so as to replace the way of distinguishing by the human eye, thereby realizing the accurate and efficient laser focusing and ensuring the stability and improvement of the laser engraving process quality.

[0042] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart of a laser focusing method provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of laser focusing when the laser beam height is equal to the focal length, provided by an embodiment of the present invention.

[0046] Figure 3 This is a schematic diagram of laser focusing when the laser beam height is less than the focal length, provided by an embodiment of the present invention.

[0047] Figure 4 This is a schematic diagram of laser focusing when the laser beam height is greater than the focal length, provided by an embodiment of the present invention.

[0048] Figure 5 This is a flowchart of another laser focusing method provided in an embodiment of the present invention;

[0049] Figure 6 This is a laser spot matrix diagram provided by an embodiment of the present invention when the laser height corresponding to the minimum average laser spot diameter is neither the maximum nor the minimum value among multiple different laser heights;

[0050] Figure 7 This is a laser spot matrix diagram provided by an embodiment of the present invention when the laser height corresponding to the minimum average diameter of the laser spot is the minimum among multiple different laser heights;

[0051] Figure 8 This is a laser spot matrix diagram provided by an embodiment of the present invention when the laser height corresponding to the minimum average laser spot diameter is the maximum value among multiple different laser heights;

[0052] Figure 9 This is a flowchart of another laser focusing method provided in an embodiment of the present invention;

[0053] Figure 10 This is a schematic diagram of a laser-engraved information pattern provided in an embodiment of the present invention;

[0054] Figure 11 This is a structural block diagram of a laser focusing control device provided in an embodiment of the present invention. Detailed Implementation

[0055] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort should belong to the scope of protection of the present application.

[0056] It should be noted that the terms "first", "second" and the like in the description and claims of the present application and the above drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0057] The embodiment of the present application provides a focusing method of a laser, Figure 1 is a flow chart of the focusing method of the laser provided by the embodiment of the present application, referring to Figure 1 , the focusing method of the laser comprises:

[0058] S110, acquiring a current reference height and a current height adjustment step distance of the laser.

[0059] S120, taking the current reference height as a starting point, determining a plurality of different laser heights of the laser according to the current height adjustment step distance, wherein the plurality of different laser heights at least include the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height.

[0060] Specifically, the laser height of the laser is the distance from the laser to the surface to be engraved, wherein the surface to be engraved is the surface of the product which needs to be engraved with pattern information such as characters, numbers, letters and graphics.

[0061] Referring to Figures 2-4 , the laser is focused on the surface to be engraved 11 after passing through the convex mirror 21 in the laser, including three cases: as shown in Figure 2 , the height of the laser to the product is just equal to the focal length, the laser emitted by the laser is focused on a point on the surface to be engraved 11, at this time the formed spot has the deepest color and the smallest diameter; as shown in Figure 3As shown, when the height of the laser from the surface 11 to be laser-engraved is less than the focal length, the laser beam emitted by the laser is not focused on a single point on the surface 11. Therefore, the resulting laser spot is slightly lighter in color and slightly larger in diameter. Figure 4 As shown, when the laser's height relative to the product is greater than the focal length, the laser beam emitted by the laser is not focused at a single point on the surface 11 to be laser-engraved. The resulting laser spot is slightly lighter in color and larger in diameter. Therefore, the size of the laser spot formed on the surface 11 to be laser-engraved is related to the distance between the laser and the surface 11. The area of ​​the laser spot at the focal point is the smallest, and therefore the power density of the laser spot at the focal point is the highest, making it easier for the material on the surface 11 to evaporate.

[0062] The focusing process of a laser can be transformed into determining the laser height that produces the smallest laser spot. The shape of the laser spot is usually circular or approximately circular, so the spot area can be compared by comparing the spot diameter. Setting multiple different laser heights allows the laser to etch a laser spot at these heights, resulting in spots of different diameters. This facilitates finding the smallest diameter spot or a spot with a diameter close to the smallest diameter, thus achieving laser focusing. In this embodiment, the step of setting multiple different laser heights is as follows: setting a reference height and a height adjustment step size for the laser; starting from the reference height, determining multiple different laser heights based on the height adjustment step size; wherein the multiple different laser heights include at least the reference height, at least one first height higher than the reference height, and at least one second height lower than the reference height. Since the currently set multiple laser heights may not include the laser height corresponding to the focal length, meaning the smallest laser spot etched at the set multiple laser heights may not be the smallest area spot (the laser spot etched at the laser height corresponding to the focal length), there are situations where multiple laser height settings are required. The current reference height is the reference height used when setting multiple different laser heights, and the current height adjustment step is the height adjustment step used when setting multiple different laser heights.

[0063] It should be noted that the laser height corresponding to the focal length can be equal to or approximately equal to the focal length, as long as the focus qualification preset condition is met. The focus qualification preset condition can be set according to actual needs. In addition, since each time multiple different laser heights are set, there will be a minimum spot at each of the different laser heights. To distinguish it from the spot laser-etched at the laser height corresponding to the focal length, the spot laser-etched at the laser height corresponding to the focal length will be referred to as the target spot, and the laser height corresponding to the focal length will be referred to as the target laser height.

[0064] S130. At each laser height, control the laser to etch multiple light spots and determine the average diameter of the light spot corresponding to each laser height.

[0065] Specifically, the distance between the laser and the surface to be engraved is adjusted, so as to adjust the engraving height of the laser. At each engraving height, the laser is controlled to engrave a plurality of spots, that is, a group of spots is engraved at each engraving height. According to the diameters of the plurality of spots engraved at each engraving height, the average diameter of the spots corresponding to each engraving height is determined. Determining the average diameter of the spots corresponding to each engraving height can improve the accuracy and reliability of the data and eliminate random errors, compared with obtaining the diameter of a spot at each engraving height. The number of spots engraved at different engraving heights can be the same or different, and can be set according to actual needs. For example, the number of spots engraved at each engraving height can be 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 20, etc., and can be set according to actual needs.

[0066] S140, determining whether the engraving height corresponding to the minimum average diameter of the spots meets a preset focus qualification condition.

[0067] Specifically, the minimum average diameter of the spots can be understood as the minimum average value in the average diameters of the plurality of spot groups obtained at the plurality of different engraving heights. After the minimum average diameter of the spots is determined, it can be determined which group of spots is the minimum spot in the current focus process. Since the engraving height of the group of spots is the engraving height closest to the focal length among the plurality of different engraving heights, whether the engraving height corresponding to the minimum average diameter of the spots meets the preset focus qualification condition is judged. If it meets, the engraving height is determined as the target engraving height, and the focus of the laser is completed. If it does not meet, the plurality of different engraving heights are re-set, and the next round of focus is continued.

[0068] Optionally, in an embodiment of the present application, whether the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition can be determined according to the range to which the diameter of the spot laser-engraved by the laser height belongs. In another embodiment of the present application, since the smaller the difference between the diameters of adjacent spots is, the more accurate the focus effect is, the step of determining whether the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition can specifically include: determining whether the difference between the diameters of two adjacent spots laser-engraved by the laser height corresponding to the minimum average spot diameter satisfies a preset difference value, and if yes, determining that the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition, and if no, determining that the laser height corresponding to the minimum average spot diameter does not satisfy the preset focus qualification condition. In another embodiment of the present application, whether the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition can be determined by determining whether the range to which the diameter of the spot laser-engraved by the laser height corresponding to the minimum average spot diameter belongs and the difference between the diameters of two adjacent spots laser-engraved by the laser height corresponding to the minimum average spot diameter satisfy respective corresponding conditions.

[0069] In the case of no satisfaction, the next reference height and the next height adjustment step distance are determined according to the size relationship of the average spot diameters corresponding to the plurality of different laser heights, and the next reference height and the next height adjustment step distance are respectively replaced by the current reference height and the current height adjustment step distance, and the above steps are repeated until the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition.

[0070] Specifically, in the case of no satisfaction, the next reference height and the next height adjustment step distance are determined according to the size relationship of the average spot diameters corresponding to the plurality of different laser heights currently set, the plurality of laser heights set for the next round of focusing can be determined according to the analysis result of the current round of focusing, the total number of laser height settings when the focusing is completed is reduced, and thus the best search effect is achieved with the least number of measurements.

[0071] The focus method of the laser provided by the present application can find the laser height corresponding to the minimum average spot diameter by laser-engraving spots at a plurality of different laser heights and measuring the spot diameters, and then find a plurality of laser heights again based on the laser height, and determine whether the difference between the diameters of two adjacent spots laser-engraved by the laser height corresponding to the minimum average spot diameter satisfies the preset focus qualification condition, so as to complete the laser focusing. Through the method, the laser focusing situation can be reflected digitally, the laser focal height can be accurately positioned according to product requirements, and the laser focusing is completed accurately and efficiently by replacing the way of distinguishing by the human eye, so that the stability and improvement of the laser-engraving process quality are ensured.

[0072] Figure 5is a flowchart of another focusing method of a laser provided by an embodiment of the present application, referring to Figure 5 The focusing method of the laser comprises:

[0073] S210, acquiring a current reference height and a current height adjustment step of the laser.

[0074] S220, taking the current reference height as a starting point, determining a plurality of different laser heights of the laser according to the current height adjustment step, wherein the plurality of different laser heights at least include the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height.

[0075] S230, at each laser height, controlling the laser to engrave a plurality of light spots, and determining an average diameter of the light spots corresponding to each laser height.

[0076] S240, judging whether the laser height corresponding to the minimum average diameter of the light spots satisfies a preset focusing qualification condition, if yes, executing step S250, and if no, executing step S260.

[0077] S250, determining that the focusing of the laser is successful.

[0078] S260, determining a size relationship of the average diameters of the light spots corresponding to the different laser heights; if the laser height corresponding to the minimum average diameter of the light spots is the minimum value in the plurality of different laser heights, executing step S2710; if the laser height corresponding to the minimum average diameter of the light spots is the maximum value in the plurality of different laser heights, executing step S2720; and if the laser height corresponding to the minimum average diameter of the light spots is neither the maximum value nor the minimum value in the plurality of different laser heights, executing step S2730.

[0079] S2710, determining the current height adjustment step as a next height adjustment step, determining a difference between the minimum value in the plurality of different laser heights and (n-1) / 2 times of the height adjustment step as a next reference height, and replacing the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and returning to execute step S210.

[0080] S2720, determining the current height adjustment step as a next height adjustment step, determining a sum of the maximum value in the plurality of different laser heights and (n-1) / 2 times of the height adjustment step as a next reference height, and replacing the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and returning to execute step S210.

[0081] S2730, determining the laser height corresponding to the minimum average spot diameter as the next reference height, determining the difference between the two laser heights adjacent to the laser height corresponding to the minimum average spot diameter and the ratio of n-1 as the next height adjustment step, and replacing the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and returning to step S210.

[0082] In the laser focusing method provided by the embodiment of the present application, the step of determining the next reference height and the next height adjustment step according to the size relationship of the average spot diameters corresponding to the plurality of different laser heights comprises: in the case that the laser height corresponding to the minimum average spot diameter is the minimum value in the plurality of different laser heights, determining the current height adjustment step as the next height adjustment step, and determining the difference between the minimum value in the plurality of different laser heights and the height adjustment step multiplied by (n-1) / 2 as the next reference height; in the case that the laser height corresponding to the minimum average spot diameter is the maximum value in the plurality of different laser heights, determining the current height adjustment step as the next height adjustment step, and determining the sum of the maximum value in the plurality of different laser heights and the height adjustment step multiplied by (n-1) / 2 as the next reference height; in the case that the laser height corresponding to the minimum average spot diameter is neither the maximum value nor the minimum value in the plurality of different laser heights, determining the laser height corresponding to the minimum average spot diameter as the next reference height, and determining the ratio of the difference between the two laser heights adjacent to the laser height corresponding to the minimum average spot diameter and (n-1) as the next height adjustment step. Wherein, n is an odd number greater than 3, and n is the number of the plurality of different laser heights, the number of the first height is equal to the number of the second height. According to the size relationship of the average spot diameters corresponding to the plurality of different laser heights, the correct direction of the correct focal length can be determined in the technical solution provided by the embodiment of the present application, so that the laser height can be automatically "pulled" to the correct area in the next measurement, and the invalid measurement in the wrong area is avoided. In addition, the total number of the laser heights can be reduced according to the analysis result of the current focusing, and the best search effect is achieved with the least number of measurements.

[0083] For example, the current reference height is taken as the initial laser height, the current height adjustment step is taken as the initial height adjustment step, 10 spots are engraved under each laser height, and n is equal to 7. Two rounds of focusing are taken as an example to explain and illustrate. In the first round of focusing process:

[0084] Adjust the height of the laser to the initial reference height H, control the laser to engrave 10 spots, which are spot HD1, spot HD2, spot HD3, spot HD4, spot HD5, spot HD6, spot HD7, spot HD8, spot HD9, and spot HD10 respectively; measure the diameters of the spots HD1 to HD10, and calculate the average spot diameter HD of the 10 spots;

[0085] Adjust the height of the laser to the height H+D (the first first height), wherein D is the initial height adjustment step; control the laser to engrave 10 spots, which are spot HE1, spot HE2, spot HE3, spot HE4, spot HE5, spot HE6, spot HE7, spot HE8, spot HE9, and spot HE10 respectively; measure the diameters of the spots HE1 to HE10, and calculate the average spot diameter HE of the 10 spots;

[0086] Adjust the height of the laser to H+2D (the second first height), control the laser to engrave 10 spots, which are spot HF1, spot HF2, spot HF3, spot HF4, spot HF5, spot HF6, spot HF7, spot HF8, spot HF9, and spot HF10 respectively; measure the diameters of the spots HF1 to HF10, and calculate the average spot diameter HF of the 10 spots;

[0087] Adjust the height of the laser to H+3D (the third first height), control the laser to engrave 10 spots, which are spot HG1, spot HG2, spot HG3, spot HG4, spot HG5, spot HG6, spot HG7, spot HG8, spot HG9, and spot HG10 respectively; measure the diameters of the spots HG1 to HG10, and calculate the average spot diameter HG of the 10 spots;

[0088] Adjust the height of the laser to the height H-D (the first second height); control the laser to engrave 10 spots, which are spot HC1, spot HC2, spot HC3, spot HC4, spot HC5, spot HC6, spot HC7, spot HC8, spot HC9, and spot HC10 respectively; measure the diameters of the spots HC1 to HC10, and calculate the average spot diameter HC of the 10 spots;

[0089] Adjust the height of the laser to H-2D (the second second height), control the laser to engrave 10 spots, which are spot HB1, spot HB2, spot HB3, spot HB4, spot HB5, spot HB6, spot HB7, spot HB8, spot HB9, and spot HB10 respectively; measure the diameters of the spots HB1 to HB10, and calculate the average spot diameter HB of the 10 spots;

[0090] Adjust the laser height to H-3D (the third second height), control the laser to engrave 10 light spots, namely light spot HA1, light spot HA2, light spot HA3, light spot HA4, light spot HA5, light spot HA6, light spot HA7, light spot HA8, light spot HA9, light spot HA10; measure the diameters of light spots HA1 to HA10, and calculate the average light spot diameter HA of these 10 light spots.

[0091] After analyzing the size relationship of the average light spot diameters corresponding to multiple different laser heights, there are three situations for the laser height corresponding to the minimum average light spot diameter among the set multiple different laser heights, namely: the laser height corresponding to the minimum average light spot diameter is the minimum value among the multiple different laser heights, the laser height corresponding to the minimum average light spot diameter is the maximum value among the multiple different laser heights, and the laser height corresponding to the minimum average light spot diameter is neither the maximum value nor the minimum value among the multiple different laser heights. In different situations, the setting method of the laser height in the next focusing process is different.

[0092] As Figure 6 shown, if the size relationship of the measured average light spot diameters is: HA>HB>HC>HD<HE<HF<HG, the average light spot diameter HD is the minimum value, and the laser height corresponding to the average light spot diameter HD is the initial reference height H, then the corresponding situation is that the laser height corresponding to the minimum average light spot diameter is neither the maximum value nor the minimum value among the multiple different laser heights. Divide the difference between the laser heights H-D and H+D corresponding to HC and HE into 6 parts, each part with a height of D1, determine D1 as the next height adjustment step size, and the laser height H corresponding to the average light spot diameter HD as the next reference height, and name it H1. In the second round of focusing process:

[0093] Since the laser height H1 and the laser height H are at the same height, the average light spot diameter HD of light spots HD1, HD2, HD3, HD4, HD5, HD6, HD7, HD8, HD9, HD10 is carried over as the average light spot diameter H1D for the next round of focusing;

[0094] <>

[0095] Adjust the laser height of the laser to H + D1 (the first first height of the second round of focusing), control the laser to engrave 10 light spots, namely light spot H1E1, light spot H1E2, light spot H1E3, light spot H1E4, light spot H1E5, light spot H1E6, light spot H1E7, light spot H1E8, light spot H1E9, light spot H1E10; measure the diameters of light spots H1E1 to H1E10, and calculate the average light spot diameter H1E of these 10 light spots.

[0095] Adjust the laser engraving height of the laser to H1+D2 (the second first height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1F1, light spot H1F2, light spot H1F3, light spot H1F4, light spot H1F5, light spot H1F6, light spot H1F7, light spot H1F8, light spot H1F9, and light spot H1F10 respectively; measure the diameters of the light spots H1F1~H1F10, and calculate the average value H1F of the diameters of the 10 light spots;

[0096] Adjust the laser engraving height of the laser to H1+D3 (the third first height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1G1, light spot H1G2, light spot H1G3, light spot H1G4, light spot H1G5, light spot H1G6, light spot H1G7, light spot H1G8, light spot H1G9, and light spot H1G10 respectively; measure the diameters of the light spots H1G1~H1G10, and calculate the average value H1G of the diameters of the 10 light spots;

[0097] Adjust the laser engraving height of the laser to H1-D1 (the first second height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1C1, light spot H1C2, light spot H1C3, light spot H1C4, light spot H1C5, light spot H1C6, light spot H1C7, light spot H1C8, light spot H1C9, and light spot H1C10 respectively; measure the diameters of the light spots H1C1~H1C10, and calculate the average value H1C of the diameters of the 10 light spots;

[0098] Adjust the laser engraving height of the laser to H1-D2 (the second second height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1B1, light spot H1B2, light spot H1B3, light spot H1B4, light spot H1B5, light spot H1B6, light spot H1B7, light spot H1B8, light spot H1B9, and light spot H1B10 respectively; measure the diameters of the light spots H1B1~H1B10, and calculate the average value H1B of the diameters of the 10 light spots;

[0099] Adjust the laser engraving height of the laser to H1-D3 (the third second height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1A1, light spot H1A2, light spot H1A3, light spot H1A4, light spot H1A5, light spot H1A6, light spot H1A7, light spot H1A8, light spot H1A9, and light spot H1A10 respectively; measure the diameters of the light spots H1A1~H1A10, and calculate the average value H1A of the diameters of the 10 light spots;

[0100] In this way, the average values H1A~H1G of the diameters of the 10 light spots corresponding to the 10 laser engraving heights in the second round of focusing are obtained.

[0101] As shown in Figure 7 the size relationship of the average values of the measured spot diameters is: HA < HB < HC < HD < HE < HF < HG, the average value of the spot diameter HA is the minimum value, and the laser height corresponding to the average value of the spot diameter HA is the height H-3D. The corresponding case is that the laser height corresponding to the minimum average diameter of the spot is the minimum value among the plurality of different laser heights. The height H-6D is determined as the next reference height H1, and the height D is determined as the next height adjustment step. In the second focusing process:

[0102] The laser height of the laser is adjusted to H1, and the laser is controlled to engrave 10 spots, which are spot H1D1, spot H1D2, spot H1D3, spot H1D4, spot H1D5, spot H1D6, spot H1D7, spot H1D8, spot H1D9, and spot H1D10. The diameters of the spots H1D1 to H1D10 are measured, and the average value of the spot diameters of the 10 spots H1D is calculated.

[0103] The laser height of the laser is adjusted to H1+D (the first height of the second focusing), and the laser is controlled to engrave 10 spots, which are spot H1E1, spot H1E2, spot H1E3, spot H1E4, spot H1E5, spot H1E6, spot H1E7, spot H1E8, spot H1E9, and spot H1E10. The diameters of the spots H1E1 to H1E10 are measured, and the average value of the spot diameters of the 10 spots H1E is calculated.

[0104] The laser height of the laser is adjusted to H1+2D (the second height of the second focusing), and the laser is controlled to engrave 10 spots, which are spot H1F1, spot H1F2, spot H1F3, spot H1F4, spot H1F5, spot H1F6, spot H1F7, spot H1F8, spot H1F9, and spot H1F10. The diameters of the spots H1F1 to H1F10 are measured, and the average value of the spot diameters of the 10 spots H1F is calculated.

[0105] Since the laser height H1+3D (the third height of the second focusing) and the laser height H-3D are the same height, the average value of the spot diameters HA1, HA2, HA3, HA4, HA5, HA6, HA7, HA8, HA9, and HA10 is used as the average value of the spot diameters H1G of the second focusing.

[0106] Adjust the laser's beam height to H1-D (the first second height in the second round of focusing), and control the laser to etch 10 laser spots, namely spot H1C1, spot H1C2, spot H1C3, spot H1C4, spot H1C5, spot H1C6, spot H1C7, spot H1C8, spot H1C9, and spot H1C10; measure the diameter of spot H1C1 to spot H1C10, and calculate the average diameter H1C of the 10 spots;

[0107] Adjust the laser's beam height to H1-2D (the second height in the second round of focusing), and control the laser to etch 10 laser spots, namely spot H1B1, spot H1B2, spot H1B3, spot H1B4, spot H1B5, spot H1B6, spot H1B7, spot H1B8, spot H1B9, and spot H1B10; measure the diameter of spots H1B1 to H1B10, and calculate the average diameter H1B of the 10 spots;

[0108] Adjust the laser's laser height to H1-3D (the third second height in the second round of focusing), and control the laser to etch 10 laser spots, namely spot H1A1, spot H1A2, spot H1A3, spot H1A4, spot H1A5, spot H1A6, spot H1A7, spot H1A8, spot H1A9, and spot H1A10; measure the diameter of spot H1A1 to spot H1A10, and calculate the average diameter H1A of the 10 spots;

[0109] Thus, the average spot diameters H1A~H1G corresponding to the 10 laser heights in the second focusing process are obtained.

[0110] like Figure 8 As shown, if the average measured spot diameters are in the following order: HA > HB > HC > HD > HE > HF > HG, and the average spot diameter HG is the minimum, then the laser height corresponding to the average spot diameter HG is height H+3D. This means the laser height corresponding to the minimum average spot diameter is the maximum of several different laser heights. Height H+6D is determined as the next reference height H1, and height D is determined as the next height adjustment step. During the second round of focusing:

[0111] The laser beam height is adjusted to H1, and the laser is controlled to etch 10 laser spots, namely H1D1, H1D2, H1D3, H1D4, H1D5, H1D6, H1D7, H1D8, H1D9, and H1D10. The diameters of spots H1D1 to H1D10 are measured, and the average diameter H1D of the 10 spots is calculated.

[0112] Adjust the laser engraving height of the laser to H1+D (the first first height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1E1, light spot H1E2, light spot H1E3, light spot H1E4, light spot H1E5, light spot H1E6, light spot H1E7, light spot H1E8, light spot H1E9, and light spot H1E10 respectively; measure the diameters of the light spots H1E1~H1E10, and calculate the average value H1E of the diameters of the 10 light spots;

[0113] Adjust the laser engraving height of the laser to H1+2D (the second first height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1F1, light spot H1F2, light spot H1F3, light spot H1F4, light spot H1F5, light spot H1F6, light spot H1F7, light spot H1F8, light spot H1F9, and light spot H1F10 respectively; measure the diameters of the light spots H1F1~H1F10, and calculate the average value H1F of the diameters of the 10 light spots;

[0114] Adjust the laser engraving height of the laser to H1+3D (the third first height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1G1, light spot H1G2, light spot H1G3, light spot H1G4, light spot H1G5, light spot H1G6, light spot H1G7, light spot H1G8, light spot H1G9, and light spot H1G10 respectively; measure the diameters of the light spots H1G1~H1G10, and calculate the average value H1G of the diameters of the 10 light spots;

[0115] Adjust the laser engraving height of the laser to H1-D (the first second height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1C1, light spot H1C2, light spot H1C3, light spot H1C4, light spot H1C5, light spot H1C6, light spot H1C7, light spot H1C8, light spot H1C9, and light spot H1C10 respectively; measure the diameters of the light spots H1C1~H1C10, and calculate the average value H1C of the diameters of the 10 light spots;

[0116] Adjust the laser engraving height of the laser to H1-2D (the second second height of the second round of focusing), control the laser to engrave 10 light spots, which are light spot H1B1, light spot H1B2, light spot H1B3, light spot H1B4, light spot H1B5, light spot H1B6, light spot H1B7, light spot H1B8, light spot H1B9, and light spot H1B10 respectively; measure the diameters of the light spots H1B1~H1B10, and calculate the average value H1B of the diameters of the 10 light spots;

[0117] Since the laser height H1-3D (the third second height of the second round of focusing) and the laser height H+3D are consistent, the average spot diameter of the light spots HG1, HG2, HG3, HG4, HG5, HG6, HG7, HG8, HG9, HG10, i.e. HG, is used as the average spot diameter H1A of the second round of focusing.

[0118] In this way, the average spot diameters H1A-H1G corresponding to the 10 laser heights in the second round of focusing are obtained.

[0119] In each of the above cases, after the average spot diameters H1A-H1G corresponding to the 10 laser heights in the second round of focusing are obtained, it is determined whether the laser height corresponding to the minimum average spot diameter in the second round of focusing satisfies the preset focusing qualification condition; if yes, the minimum spot in the second round of focusing is the target spot, the laser height corresponding to the minimum average spot diameter in the second round of focusing is determined as the target laser height, and the focusing of the laser is completed; if no, the reference height and the height adjustment step distance of the third round are determined according to the size relationship of the average spot diameters obtained in the second round of focusing and based on the reference height and the height adjustment step distance used in the second round, and the focusing of the third round is performed. The above steps are repeated until the laser height corresponding to the minimum value of the average spot diameters HnA, HnB, HnC, HnD, HnE, HnF, HnG obtained in the n+1th round of focusing satisfies the laser requirement of the product to be laser-engraved; n is a natural number.

[0120] Figure 9 is a flowchart of another laser focusing method provided by an embodiment of the present application, referring to Figure 9 The laser focusing method comprises the following steps.

[0121] S310, obtaining the current reference height and the current height adjustment step distance of the laser.

[0122] S320, taking the current reference height as a starting point, determining a plurality of different laser heights of the laser according to the current height adjustment step distance, wherein the plurality of different laser heights at least include the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height.

[0123] S330, controlling the laser to laser-engrave a plurality of light spots at each laser height.

[0124] S340, measuring the diameters of the plurality of light spots laser-engraved at each laser height by an optical image measuring instrument.

[0125] S350, calculating the average diameters of the plurality of light spots at each laser height to obtain the average spot diameter corresponding to each laser height.

[0126] S360, determine whether the difference between the diameters of the two adjacent laser marks engraved by the laser height corresponding to the minimum average diameter of the laser spot is less than or equal to the maximum allowed deviation of the laser-engraved information line width, if yes, execute step S370, if no, execute step S380.

[0127] S370, determine that the difference between the diameters of the two adjacent laser marks engraved by the laser height corresponding to the minimum average diameter of the laser spot meets the preset focus qualification condition, and determine that the laser is focused successfully.

[0128] S380, determine that the difference between the diameters of the two adjacent laser marks engraved by the laser height corresponding to the minimum average diameter of the laser spot does not meet the preset focus qualification condition, and determine the size relationship of the average diameters of the laser spots corresponding to different laser heights; if the laser height corresponding to the minimum average diameter of the laser spot is the minimum value among the plurality of different laser heights, execute step S3910; if the laser height corresponding to the minimum average diameter of the laser spot is the maximum value among the plurality of different laser heights, execute step S3920; if the laser height corresponding to the minimum average diameter of the laser spot is neither the maximum value nor the minimum value among the plurality of different laser heights, execute step S3930.

[0129] S3910, determine the current height adjustment step as the next height adjustment step, determine the difference between the minimum value among the plurality of different laser heights and the (n-1) / 2 times of the height adjustment step as the next reference height, and replace the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and return to execute step S310.

[0130] S3920, determine the current height adjustment step as the next height adjustment step, determine the sum of the maximum value among the plurality of different laser heights and the (n-1) / 2 times of the height adjustment step as the next reference height, and replace the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and return to execute step S310.

[0131] S3930, determine the laser height corresponding to the minimum average diameter of the laser spot as the next reference height, determine the ratio of the difference between the two laser heights adjacent to the laser height corresponding to the minimum average diameter of the laser spot and (n-1) as the next height adjustment step, and replace the next reference height and the next height adjustment step with the current reference height and the current height adjustment step respectively, and return to execute step S310.

[0132] The focusing method of the laser provided by the embodiment of the present application comprises the following steps: measuring the diameters of a plurality of laser-engraved spots at each laser height by means of an optical image measuring instrument; and calculating the average value of the diameters of the plurality of laser-engraved spots at each laser height to obtain the average diameter of the spot corresponding to each laser height. The optical image measuring instrument can acquire a spot image, and the diameter information of the spot can be obtained according to the spot image, thereby realizing the high efficiency of the spot diameter measurement.

[0133] In addition, the step of determining whether the difference between the diameters of the two adjacent laser-engraved spots at the laser height corresponding to the minimum average diameter of the spot satisfies the preset focusing qualification condition comprises the following steps: determining whether the difference between the diameters of the two adjacent laser-engraved spots at the laser height corresponding to the minimum average diameter of the spot is less than or equal to the maximum allowed deviation of the laser-engraved information line width; if yes, it is determined that the laser height corresponding to the minimum average diameter of the spot satisfies the preset focusing qualification condition; and if no, it is determined that the laser height corresponding to the minimum average diameter of the spot does not satisfy the preset focusing qualification condition. Since the size of the spot diameter is affected by the power of the laser during laser engraving and is also affected by the input method of the text, it is difficult to determine the spot diameter or the range of the spot diameter that satisfies the focusing requirement. The embodiment of the present application determines whether the difference between the diameters of the two adjacent laser-engraved spots at the laser height corresponding to the minimum average diameter of the spot is less than or equal to the maximum allowed deviation of the laser-engraved information line width, thereby facilitating the definition of the preset focusing qualification condition that satisfies the laser-engraving requirement of the product.

[0134] Further, before determining whether the spot laser-engraved at the laser height corresponding to the minimum average diameter of the spot is less than or equal to the maximum allowed deviation of the laser-engraved information line width, the method further comprises the following steps:

[0135] The maximum allowed deviation of the laser-engraved information line width is determined according to the maximum allowed line width of the laser-engraved information and the minimum allowed line width of the laser-engraved information.

[0136] Specifically, the laser-engraved information is generated by filling a plurality of laser-engraved lines, and the laser-engraved lines are formed by connecting the spots, and the difference between the diameters of the adjacent spots should be less than or equal to the maximum allowed deviation SPEC of the laser-engraved information line width. Taking the letter “I” as an example, as shown in Figure 10 W1 is the minimum allowed line width of the pattern of the letter “I”, W2 is the maximum allowed line width of the pattern of the letter “I”, and SPEC=(W2-W1) / 2.

[0137] On the basis of the above-mentioned embodiments, the focusing method of the laser further comprises the following steps: acquiring the focal length range of the laser; and determining the initial reference height and the initial height adjustment step distance of the laser according to the focal length range of the laser.

[0138] Specifically, the step of determining the initial reference height of the laser and the initial height adjustment step distance according to the focal length range of the laser includes: determining the initial reference height of the laser according to the middle value of the focal length range of the laser; and determining the initial height adjustment step distance according to the focal length range of the laser and the preset number of different laser heights. The middle value of the focal length range is equal to one half of the sum of the minimum distance and the maximum distance in the focal length range. The focal length ranges of lasers of different brands and models are different, and the laser information usually includes the focal length range of the laser; or the focal length range of the laser can be obtained by measurement. The step of measuring the focal length range of the laser can include: controlling the laser to emit light at a rated power and irradiate the metal sheet; and moving the metal sheet up and down to adjust the distance between the metal sheet and the laser, to determine the distance range between the metal sheet and the laser corresponding to the continuous appearance of bright light on the metal sheet (the upper moving distance range of the metal sheet corresponds to no bright light on the metal sheet, the middle moving distance range of the metal sheet corresponds to bright light on the metal sheet, and the lower moving distance range of the metal sheet corresponds to no bright light on the metal sheet), and the distance range is determined as the focal length range of the laser.

[0139] On the basis of the above-mentioned embodiments, optionally, at each laser height, the laser is controlled to laser-engrave a plurality of light spots, including:

[0140] At each laser height, the laser is controlled to laser-engrave a plurality of light spots arranged in sequence on the same surface to be laser-engraved, so that the plurality of light spots laser-engraved at different laser heights form a light spot matrix (for example, Figures 6-8 ) on the same surface to be laser-engraved, so that the optical image measuring instrument can obtain the light spot matrix image, and the diameter of each laser-engraved light spot at each laser height can be measured by the optical image measuring instrument through one-time shooting, thereby reducing the number of times of shooting.

[0141] Reference Figure 11 The embodiment of the present application also provides a focusing control device of a laser, which is used for executing the focusing method of the laser according to any embodiment of the present application, and includes:

[0142] The height and step distance obtaining module 10 is used for obtaining the current reference height and the current height adjustment step distance of the laser.

[0143] The laser height determining module 20 is used for determining a plurality of different laser heights of the laser according to the current height adjustment step distance with the current reference height as a starting point, wherein the plurality of different laser heights at least include the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height.

[0144] The control module 30 is used for controlling the laser to laser-engrave a plurality of light spots at each laser height.

[0145] The average diameter determination module 40 is configured to determine the average diameter of the light spot corresponding to each laser height;

[0146] The focus determination module 50 is configured to determine whether the laser height corresponding to the minimum average diameter of the light spot satisfies a preset focus qualification condition.

[0147] The height and step adjustment module 60 is configured to, in the case of not satisfying the condition, determine the next reference height and the next height adjustment step according to the size relationship of the average diameters of the light spots corresponding to the plurality of different laser heights, and replace the current reference height and the current height adjustment step with the next reference height and the next height adjustment step, respectively.

[0148] The focus control device of the laser provided by the embodiments of the present application can perform the focus control method of the laser provided by any of the embodiments of the present application, and has the function modules and beneficial effects corresponding to the execution method.

[0149] The embodiments of the present application also provide a laser engraving device, which comprises a laser and the focus control device of the laser provided by any of the embodiments of the present application, and has the corresponding beneficial effects, which will not be described herein.

[0150] It should be noted that the above are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A focusing method for a laser, characterized in that, include: Obtain the laser's current reference height and current height adjustment step size; Starting from the current reference height, the step size is adjusted according to the current height to determine multiple different laser heights of the laser. The multiple different laser heights include at least the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height. At each laser height, the laser is controlled to etch multiple light spots, and the average diameter of the light spot corresponding to each laser height is determined; Determine whether the laser height corresponding to the minimum average spot diameter meets the preset conditions for focusing qualification. If the conditions are not met, the next reference height and the next height adjustment step are determined based on the relationship between the average diameters of the laser spots corresponding to the multiple different laser heights. The next reference height and the next height adjustment step are then replaced with the current reference height and the current height adjustment step, respectively. The above steps are repeated until the laser height corresponding to the smallest average laser spot diameter meets the preset conditions for focusing.

2. The focusing method for a laser according to claim 1, characterized in that, The step of determining the next reference height and the next height adjustment step distance based on the relationship between the average diameters of the laser spots corresponding to the multiple different laser heights includes: When the laser height corresponding to the minimum average diameter of the laser spot is the minimum among the plurality of different laser heights, the current height adjustment step is determined as the next height adjustment step, and the difference between the minimum among the plurality of different laser heights and (n-1) / 2 times the height adjustment step is determined as the next reference height. When the laser height corresponding to the minimum average laser spot diameter is the maximum value among the plurality of different laser heights, the current height adjustment step is determined as the next height adjustment step, and the sum of the maximum value among the plurality of different laser heights and (n-1) / 2 times the height adjustment step is determined as the next reference height; When the laser height corresponding to the minimum average laser diameter is neither the maximum nor the minimum among the plurality of different laser heights, the laser height corresponding to the minimum average laser diameter is determined as the next reference height, and the ratio of the difference between two laser heights adjacent to the laser height corresponding to the minimum average laser diameter to (n-1) is determined as the next height adjustment step. Where n is an odd number greater than 3, and n is the number of the plurality of different laser heights.

3. The focusing method for a laser according to claim 1, characterized in that, Determine the average spot diameter corresponding to each laser height, including: The diameter of the multiple laser spots laser-etched at each laser height is measured using an optical image measuring instrument. Calculate the average diameter of the plurality of laser spots at each laser height to obtain the average diameter of the laser spot corresponding to each laser height.

4. The focusing method for a laser according to claim 1, characterized in that, The determination of whether the laser height corresponding to the minimum average spot diameter meets the preset conditions for focusing qualification includes: Determine whether the difference between the diameters of two adjacent laser spots etched by the laser height corresponding to the minimum average diameter of the laser spot is less than or equal to the maximum allowable deviation of the laser engraving information line width; If so, then determine that the laser height corresponding to the minimum average spot diameter meets the preset conditions for focusing qualification; If not, then the laser height corresponding to the minimum average spot diameter does not meet the preset conditions for focusing.

5. The focusing method for a laser according to claim 4, characterized in that, Before determining whether the laser-etched spot corresponding to the laser height with the minimum average spot diameter is less than or equal to the maximum allowable deviation of the laser-etched information line width, the process also includes: The maximum permissible deviation of the laser engraving line width is determined based on the maximum permissible line width and the minimum permissible line width of the laser engraving information.

6. The focusing method for a laser according to claim 1, characterized in that, Also includes: Obtain the focal length range of the laser; Based on the focal length range of the laser, determine the initial reference height and initial height adjustment step of the laser.

7. The focusing method for a laser according to claim 6, characterized in that, The step of determining the initial reference height and initial height adjustment step distance of the laser based on the focal length range of the laser includes: The initial reference height of the laser is determined based on the median value of the focal length range of the laser. The initial height adjustment step is determined based on the focal length range of the laser and the preset number of the plurality of different laser heights.

8. The focusing method for a laser according to claim 1, characterized in that, At each laser height, controlling the laser to etch multiple laser spots includes: At each laser height, the laser is controlled to laser-etch multiple light spots arranged in sequence at intervals on the same surface to be laser-etched, so that the multiple light spots lasered at different laser heights form a light spot matrix on the same surface to be laser-etched.

9. A focusing control device for a laser, characterized in that, A focusing method for performing any one of the lasers according to claims 1 to 8, comprising: The height and step size acquisition module is used to acquire the current reference height and current height adjustment step size of the laser. A laser height determination module is used to determine multiple different laser heights of the laser by adjusting the step size according to the current reference height, starting from the current reference height. The multiple different laser heights include at least the current reference height, at least one first height higher than the current reference height, and at least one second height lower than the current reference height. The control module is used to control the laser to engrave multiple light spots at each laser height; The average diameter determination module is used to determine the average diameter of the laser spot corresponding to each laser height; The focus judgment module is used to determine whether the laser height corresponding to the minimum average diameter of the light spot meets the preset conditions for qualified focus. The height and step size adjustment module is used to determine the next reference height and the next height adjustment step size based on the relationship between the average diameter of the spot corresponding to the multiple different laser heights when the conditions are not met, and to replace the next reference height and the next height adjustment step size with the current reference height and the current height adjustment step size respectively.

10. A laser engraving device, characterized in that, Includes a laser and a focusing control device for the laser as described in claim 9.

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