Method for actuating, in particular pulsed laser sources, for cutting, engaging, marking and / or embedding workpieces, and laser plotter
By calculating the number of laser pulses for each image point or path unit in the laser plotter and using a modulation signal to control the laser source output, the problem of uneven energy when the laser plotter changes speed is solved, the engraving quality is improved, and grayscale mode is supported.
Patent Information
- Application Number
- CN202480013706.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-02-22
- Filing Date
- 2024-02-02
- Publication Date
- 2025-10-03
AI Technical Summary
In the prior art, when laser plotters have image points of different lengths, the engraving quality is impaired due to the constant laser pulses, especially the uneven energy input during the acceleration and braking phases.
By calculating the number of laser pulses before each image point or path unit, generating a modulation signal to output laser pulses at a constant pulse repetition rate, and maintaining the same number of laser pulses at each image point or path unit, the output of the laser source is controlled using the modulation signal.
It achieves the goal of keeping the energy of each image point or path unit constant when the speed changes, improves the engraving quality, and supports the implementation of grayscale mode.
Smart Images
Figure CN120752109A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a method for operating a, in particular pulsed, laser source for cutting, engraving, marking and / or inscribing workpieces, and a laser plotter therefor, as described in claims 1 and 10 . Background Art
[0002] Laser devices, particularly laser plotters, are known from the prior art, in which one or more laser sources operate. These laser plotters have a belt-driven carriage on which a focusing unit or laser head is also adjustably arranged. Flat workpieces, such as paper, sheet metal, textiles, ballpoint pens, mobile phones, tablet computers, etc., are preferably processed using a laser, particularly a laser beam. The laser beam is directed from the laser source via a deflection element to the focusing unit or laser head, where it is deflected toward the workpiece. The laser device, particularly the laser plotter, has a control unit for controlling and regulating all components. During workpiece processing, the laser source emits laser pulses at a constant pulse repetition rate, which are sent to the focusing unit during image points (so-called pixels). A disadvantage of this is that, with image points of varying lengths (as is the case during acceleration and braking phases), the constant laser pulses introduce different energies into each image point, which can impair the quality of the engraving.
[0003] The applicant has previously attempted to avoid this by reducing the preset laser power 27a-d of the laser pulse 25 in the case of longer image points 29 (especially in the acceleration phases 29a, b and the braking phase 29d) in order to reduce the energy introduced, since the pulsed laser pulse 25 is output over the entire duration of the image point 29, as in the case of Figure 3 However, this is very complex and difficult to calculate and modify all the different image points 29 . Summary of the Invention
[0004] The object of the present invention is to provide a method for controlling a (especially pulsed) laser source for cutting, engraving, marking and / or inscribing workpieces and a laser plotter therefor, in which the above-mentioned disadvantages are avoided on the one hand and a high engraving quality is achieved on the other hand.
[0005] This object is achieved by the present invention. Advantageous embodiments and method measures are described in the dependent claims.
[0006] The object of the present invention is achieved by a method for controlling a (especially pulsed) laser source for cutting, engraving, marking and / or inscribing workpieces, in which method, at the beginning of the processing process or laser processing, especially before each line or path element, a control unit calculates the number of laser pulses for an image point / path element, thereby generating a modulation signal, which releases the laser source for generating / applying laser pulses at a constant pulse repetition rate, and applies this modulation signal to the laser source, wherein the calculated number of laser pulses remains constant at further image points / path elements.
[0007] Advantageously, the same number of laser pulses with a predetermined power is emitted at each pixel / path element. This means that the same number of laser pulses is always output regardless of the length of the pixel / path element. The modulation signal triggers the corresponding duration of the laser pulses or counts the laser pulses (particularly the rising or falling edges). This ensures that the total pulse energy per path element or pixel remains constant even with varying speeds, particularly during acceleration and braking. Furthermore, grayscale modes can be achieved by scaling the number of pulses or the number of laser pulses per path element or pixel.
[0008] Compared with the prior art, the biggest advantage is that the energy introduced for a certain path unit / image point is constant. This is independent of the movement speed (acceleration, braking), otherwise the energy input will be uneven when the speed changes.
[0009] Advantageous is a measure in which the number of laser pulses is calculated using the parameters of the image resolution (DPI, dots per inch), the movement speed, and the pulse repetition rate of the constant laser pulses. This allows the energy to be input into the workpiece to be optimally adapted.
[0010] Advantageous measures include the following: the number of laser pulses per pixel / path element is calculated according to the formula "repetition rate / (resolution x movement speed) = number of laser pulses per pixel / path element." This allows for a simple calculation to determine the number of laser pulses.
[0011] Advantageous is a measure in which the result of the number of laser pulses per pixel / path element is always rounded, in particular rounded down, thereby achieving that a complete laser pulse is always emitted.
[0012] Advantageous is a measure in which a set target value is preferably used as the movement speed parameter, thereby enabling simple calculations to be performed using the set speed value.
[0013] Advantageous are measures in which the image points have different lengths, in particular different durations, during acceleration and braking of the focusing unit or laser head, while the number of laser pulses remains the same, in particular constant. This ensures that the same amount of energy is always introduced into the workpiece, regardless of the length of the image points.
[0014] Advantageous is a measure in which a calculated modulation signal for emitting a laser pulse is applied to each pixel / path element. This ensures that the laser pulse is emitted only within the modulation signal, so that the duration of the pixel can be longer.
[0015] Advantageous measures include taking into account additional parameters for the grayscale mode, in particular grayscale parameters, when calculating the number of laser pulses. This allows pixels or image points to be present not only in black and white, but also in different grayscales. This is also visible in the engraving on the workpiece.
[0016] However, the following measure is also advantageous: in grayscale mode, the new number of laser pulses is calculated from the formula "repetition rate x grayscale fraction / (resolution x movement speed) = number of laser pulses per pixel / path element", where the grayscale fraction can assume values between 0 and 1. This allows grayscale to be engraved on the workpiece.
[0017] Furthermore, the object of the invention is also achieved by a laser plotter in which the control unit is designed to calculate and apply a number of laser pulses to a focusing unit or a laser head according to any one of claims 1 to 9 .
[0018] The invention is described below in the form of exemplary embodiments, wherein it should be noted that the invention is not limited to the exemplary embodiments or solutions shown and described, but can be transferred to equivalent solutions. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 A diagrammatic representation of a laser device for processing a workpiece by means of a laser process is shown in a simplified, schematic illustration;
[0020] Figure 2 The signal course for laser processing of a line modulation signal is shown in a simplified, schematic diagram;
[0021] Figure 3 The signal course of a laser process from the prior art is shown in a simplified, schematic diagram. DETAILED DESCRIPTION
[0022] First, it should be understood that, in different embodiments, identical parts are designated by identical reference numerals or component names, and the disclosure contained throughout this specification is transferable to identical parts with identical reference numerals or component names. Similarly, orientations selected in this specification, such as top, bottom, and sideways, are all relative to the accompanying drawings and should be transferred to the new orientation if the orientation changes.
[0023] exist Figures 1 to 3 , an embodiment of a laser device 1, in particular a laser plotter 1, preferably with a camera system 2, is shown, in which a method for controlling a (in particular pulsed) laser source for cutting, engraving, marking and / or inscribing a workpiece is performed.
[0024] At least one (particularly two) beam source 4 or laser source 4 in the form of lasers 5 and 6 is arranged in the housing 3. The lasers 5 and 6 preferably act alternately on the workpiece 7 to be processed, wherein the workpiece 7 is positioned in a processing space 8 of the laser plotter 2, particularly on a processing table 9, wherein the processing table 9 is preferably height-adjustable. A preferably pulsed laser beam 10 emitted by the laser source 4 is directed via a deflection element 11 to at least one movable focusing unit 12 or laser head 12, which deflects the laser beam 10 toward the workpiece 7 and focuses it for processing. Control, particularly the position control of the laser beam 10 relative to the workpiece 7, is performed via software running in a control unit 13. The workpiece 7 is processed, preferably line by line, in the XY direction via an adjustable slide 14, preferably driven by a belt, on which the focusing unit 12 or laser head 12 is also movably arranged. It is possible, for example, to adjust the slide 14 line by line during the "engraving" process, while during the "cutting" process the slide 14 is moved according to the contour to be cut, i.e. not line by line. It is also possible to move the slide 14 according to the contour to be cut during the "engraving" process, i.e. to perform so-called vector engraving, in which a path unit is traversed.
[0025] Furthermore, for example, graphics 16 and / or text 16 are created or loaded at an external component 15, particularly a computer, laptop 15a, or control unit, using commercially available software 17 (e.g., CorelDraw, Paint, etc.) or using proprietary application software 17 (e.g., Ruby 17). These graphics and / or text are then exported or transferred to the control unit 13 of the laser device or laser plotter 1 in the form of a task (or job) 18. The data to be transferred is preferably converted by the same or different software so that the control unit 13 can process the task 18. Of course, it is also possible to input data directly at the laser plotter 1 using existing input tools 19 (e.g., a touch screen 19 or input keys) or to load the corresponding task 18 from a storage medium 20 (e.g., a cloud 20a, a USB stick 20b, etc.). After the data (particularly the task 18 or tasks 18) have been transferred or directly created or loaded from the storage medium 20, the task 18 is processed by the laser device 1 or laser plotter 1 (particularly its control unit 13). It is possible here to store and process a plurality of tasks 18 simultaneously in the laser device 1 , in particular the laser plotter 1 , and to process them one after another.
[0026] For such laser devices 1, in particular laser plotters 1, it is necessary for safety reasons that a cover 21 or door 21, which is preferably at least partially transparent, must be closed in order to start the task 18 to be completed, in which the laser beam 10 acts on the workpiece 7. Figure 1 As shown. The operator can then manually or automatically position a laser point or laser pointer 22 (in particular, laser pointer point 22a) on the inserted workpiece 7. This laser point or laser pointer is coupled into the beam path of the lasers 5, 6 and deflected via the focusing unit 12 or laser head 12 in the direction of the processing table 8. The operator can then start a task 18 for processing the workpiece 7 using the transferred settings (such as laser power, travel speed, resolution, table height, suction, etc.). At the end of task 18, the slide 14 and the focusing unit 12 or laser head 12 are then preferably adjusted to the initial position so that the finished workpiece 7 can be removed and a new processing process can then be started by inserting a new workpiece 7 or blank 7 to be processed. For the sake of completeness, it should be mentioned that even with the lid 21 open, the focusing unit 12 or laser head 12 can be adjusted using the activated laser pointer 22, but the lasers 5, 6 cannot be activated.
[0027] In the illustrated embodiment, at least one camera 23 is also provided in the camera system 2. The camera 23 is located in the lid 21, particularly centrally in the center of the lid 21. The camera 23 is used to record the processing space 8, particularly the processing table 9, so that a workpiece 7 placed on the processing table 9 can be identified and preferably displayed on an external component 15 (particularly a laptop computer 15a) and / or on a screen / touchscreen of the laser device 1. The position of the workpiece 7 is preferably recorded before processing or before the start of the processing process. For example, the focusing unit 12 or the laser head 12 can be positioned appropriately at the recording point shown via the laser pointer 22 to start the processing process or determine the height of the processing table 9. For the sake of completeness, it should be mentioned that the position of the workpiece 7 can be detected even when the lid 21 is open, that is, an image of the processing table 9 or the processing space 8 can be recorded with the lid 21 open.
[0028] In order to generate the laser beam 10 for the machining process, the Figure 2 The laser light source 4 is controlled by a frequency signal 24, thereby generating corresponding laser pulses 25 with a constant pulse repetition rate 26, in particular with a constant frequency. The frequency signal 24 can be generated directly by the control unit 13 or via a frequency generator, wherein preferably, the power level 27 for the laser pulses 25 or the laser power 27 is preferably predetermined proportionally by the pulse height 28 of the frequency signal 24, and / or the level of the laser power 27 is transmitted to the laser light source 4 via a signal from the control unit 13. When a frequency generator is used, the control unit 13 preferably controls the frequency generator. Alternatively, the laser light source 4 can also be controlled by the control unit 13 using a control signal that contains at least the pulse repetition rate 26 and the laser power 27, so that the laser light source 4 generates laser pulses 25 with a constant pulse repetition rate 26, in particular with a constant frequency. It is important that the laser beam 10 is formed by laser pulses 25 with a constant pulse repetition rate 26, wherein preferably the height 28 or pulse height 28 predetermines the laser power 27 of the lasers 5, 6, i.e., depending on the set laser power 27, a proportional pulse height 28 is preferably applied to the laser source 4, so that laser pulses 25 with a constant pulse repetition rate 26 are generated by the laser source 4.
[0029] The laser device 1 is preferably operated in so-called "raster engraving" mode, in which the workpiece 7 is processed line by line by means of image points 29 (so-called pixels 29), i.e. the image 16 or text 16 is composed of or converted from individual image points 29 or pixels 29, so that the laser light source 4 is controlled by the software of the control unit 13 in such a way that the laser beam 10 is switched on for preferably black pixels (presence of image points 29) and is switched off for preferably white pixels (absence of image points 29). For this purpose, Figure 2, a row 30 of machining processes with image points 29a-d is shown, wherein generally the image point 29c always has the same length (same size) given a given or predefined movement speed of the laser head 12, but the image points 29a, b, d are formed with different lengths (and therefore different sizes) in the acceleration phase (image points 29a, b) and in the braking phase (image point 29d) of the laser head 12, as shown in FIG. Figure 2 As shown in .
[0030] For the sake of completeness, it is also mentioned that instead of so-called raster engraving (in which engraving is performed line 30 after line 30 with image points 29), vector engraving can also be performed, in which the laser head 12 is moved in lines and thus defines so-called path units instead of image points 29, so that in vector engraving, the laser pulse 25 is calculated as a path unit.
[0031] In the novel laser plotter 1 or laser device 1 according to the invention, it is now provided that a novel method for controlling a (in particular pulsed) laser light source 4 is used, in which method a calculation of the number 31 of optical laser pulses 25 is performed for each image point / path element 29, that is, for the image points 29 or pixels 29 of a row 30 or path element, a specific number 31 of laser pulses 25 is allowed for each image point 29 or pixel 29, in particular a laser beam 10 having this number 31 of laser pulses 25 is generated for each image point / path element 29.
[0032] In order that only a specific number 31 of laser pulses 25 are emitted or provided by the laser light source 4 during an image point 29, a new type of modulation signal 32 is preferably sent by the control unit 13 to the laser light source 4. The modulation signal 32 activates the laser light source 4 via a calculated duration 33 (which corresponds at least to the calculated number 31 of laser pulses 25 at a specific pulse repetition rate 26) or a number of laser pulses (in which the laser pulses 25 are counted as rising or falling edges), so that the laser pulses 25 are emitted as a laser beam 10. Preferably, during an image point 29, a modulation signal 32 is used or applied as follows: Figure 2 , a modulation signal 32 with a duration 33 is shown in FIG. At the beginning of the image point 29, the modulation signal 32 is also sent to the laser light source 4, so that the laser pulses 25 are emitted by the laser light source 4 at a constant pulse repetition rate 26. The laser pulses 25 are generated continuously, as shown in FIG. Figure 2As is evident from the figure, and only when the image point 29 and the modulation signal 32 are applied, the laser pulse 25 is emitted in the form of the laser beam 10 according to the duration 33, that is, the laser pulse 25 is continuously generated and is always emitted only according to the duration 33 of the modulation signal 32, wherein the duration 33 is calculated such that a calculated number 31 of laser pulses 25 is emitted within the duration 33 of the modulation signal 32. Figure 2 It is clear from the figure that the duration 33 of the modulation signal is shorter than the pixel duration 34, so that the energy introduced via the laser pulse 25 is constant for the pixel 29. That is, the duration 33 of the modulation signal 32 is the same for pixel durations 34a-d of different lengths, in particular due to acceleration and braking phases, and thus the same number 31 of laser pulses 25 is always introduced per pixel / path element 29, regardless of the length of the pixel durations 34a-d of the pixel 29a-d. It should be noted that the duration 33 of the modulation signal 32 can at most correspond to the pixel duration 34 at maximum speed, and thus the laser pulse 25 is applied to the pixel 29 for the entire pixel duration 34.
[0033] It can thus be said that the control unit 13 generates a frequency signal 24 for controlling the laser light source 4 from the set parameters and / or the loaded task 18, which frequency signal has a constant pulse repetition rate 26, in particular a frequency, or generates a control signal for the laser pulses 25, which has a constant pulse repetition rate 26, in particular a frequency, wherein at the beginning of the processing process or laser processing, in particular before each line 30 or path unit, the control unit 13 calculates the number 31 of laser pulses 25 for the image point / path unit 29, thereby generating a modulation signal 32 (which releases the laser light source 4 for generating / applying laser pulses 25 with a constant pulse repetition rate 26) and applies this modulation signal to the laser light source 4, wherein the calculated number 31 of laser pulses 25 remains constant at the other image points / path units 29, that is, each image point / path unit 29 is acted upon by the same number 31 of laser pulses 25, wherein the modulation signal 32 is applied during each image point / path unit 29.
[0034] In addition, from Figure 2 It is clear from the figure that the modulation signal 32 can be minimally varied; more precisely, if a laser pulse 25 has already begun and the modulation signal 32 ends within this laser pulse 25, the modulation signal 32 will be extended to the end of this laser pulse 25. This ensures that the number 31 of laser pulses 25 is emitted completely, i.e., at full power. If the modulation signal 32 is activated during a laser pulse 25, only the next complete laser pulse 25 is emitted, so that the laser pulses 25 of full power and number 31 are always emitted.
[0035] The switching time or duration 33 of the pulsed laser 5, 6 or the laser source 4 is calculated such that a constant number 31 of laser pulses 25 is obtained for a path element or image point 29 defined along the movement path of the laser beam 10 or the laser head 12. For this purpose, in order to calculate the number (31) of laser pulses (25), defined parameters are used, preferably the following parameters:
[0036] Graphics resolution (DPI, dots per inch),
[0037] Movement speed and
[0038] ● Constant laser pulse repetition rate,
[0039] Use the following formula for this:
[0040] Repetition rate 26 / (resolution x movement speed) = number 31 of laser pulses 25 per image point / path unit 29
[0041] For example, the following parameters for the task 18 can be selected or set at the external component 15 , in particular the laptop computer 15 a , or at the laser device 1 :
[0042] Resolution: 800dpi
[0043] Travel speed: 2m / s (corresponding to 78.74 inches / s)
[0044] Laser pulse / pulse repetition rate: 200kHz (200000Hz)
[0045] From this we can conclude that:
[0046]
[0047] Since only an integer number of 31 laser pulses 25 is possible, the result of 3.175 is rounded down to 3 laser pulses 25 per image point 29 .
[0048] From the number 31 of three laser pulses 25 , the duration 33 of the modulation signal is then calculated, more precisely using the formula:
[0049] Number 31 / repetition rate 26 = duration 33
[0050] From this we can conclude that:
[0051]
[0052] For each pixel / path element 29 , a duration 33 of the modulation signal 32 of 15 μs thus results.
[0053] It is also possible to take even more parameters into account in the calculation, as is possible, for example, when engraving grayscale (i.e., grayscale mode). The grayscale or pixel frequency parameter is taken into account. The grayscale mode is an extension of the previously described calculation, wherein the number 31 of the maximum laser pulses 25 is reduced depending on the grayscale level, and then the pulse duration or duration 33 is optimized or calculated again.
[0054] For example, for grayscale mode, the following formula can be applied:
[0055] Round down value of (number 31 x grayscale ratio) = new number 31
[0056] The grayscale share is defined by the ratio of the grayscale level to be set to the maximum possible grayscale level (especially 8-bit grayscale) (grayscale level / 256).
[0057] Now, taking the previously calculated number of laser pulses 25 as 3, and selecting a grayscale level of 192, we get
[0058] Floor value of (3x(192 / 256)) = 2
[0059] This results in a new number 31 of 2 for the laser pulses 25. Assuming a repetition rate of 200 kHz (200,000 Hertz), the duration 33 of the modulation signal 32 can again be calculated:
[0060]
[0061] In grayscale mode, a duration 33 of 10 μs is thus obtained for the modulation signal 32 , so that with this parameter configuration, only two laser pulses 25 are emitted or applied per pixel / path element 29 in grayscale mode.
[0062] For each pixel / path element, a separate grayscale contribution and thus a separate number of pulses can be calculated.
[0063] For the sake of completeness, this example is chosen for illustration purposes only. Here, each pixel may have or have a separate grayscale.
[0064] When calculating the number 31 of laser pulses 25 , in particular the modulation signal 32 , for each line 30 , the control unit 13 can always perform this calculation before each line 30 , or a plurality of lines, in particular all lines 30 , can be calculated in advance.
[0065] exist Figure 3, a signal course from the prior art (PriorArt) is shown. It is clear from this that laser pulses 25 are emitted during image points 29. However, since image points 29 have a longer duration during the acceleration and braking phases, i.e., at the beginning and end of a line 30, excessive energy is introduced into workpiece 7 when laser power 27 is present. To avoid this, in the prior art, the applicant has previously attempted to adapt laser power 27a-d by applying corresponding frequency signals 24 with corresponding pulse heights 28a-d, which results in a high control effort.
[0066] In the solution according to the invention, this high control effort is prevented by introducing a modulation signal 32, since only a limited number 31 of laser pulses 25 is permitted during an image point 29, so that the laser power 27 can remain constant and thus constant energy is always introduced into the workpiece 7 even in acceleration and braking phases.
[0067] Furthermore, it is advantageous to use a maximum speed (which is set at the external component 15 or the laser device 1 ) for the displacement speed.
[0068] In principle, it can be said that the number 31 of laser pulses 25 increases with the increase of the pulse repetition rate 26 of the pulsed lasers 5, 6 and decreases with increasing image resolution (dpi) and higher movement speeds. By keeping the number of pulses 31 or the number of laser pulses 25 31 constant and thus keeping the total energy introduced per pixel 29 constant, adapting other parameters of the laser source 4 (as in the prior art) is no longer necessary or plays a secondary role.
[0069] For the sake of completeness, it is mentioned that the modulation signal 32 is applied or emitted simultaneously with or immediately after the execution of the image point 19. Furthermore, the number 31 of laser pulses 25 can be calculated before each line 30 or before a certain number of lines 30 or for all lines 30 at the start of processing.
[0070] Furthermore, individual features or combinations of features from the different exemplary embodiments shown and described may also constitute independent, inventive solutions or solutions according to the invention.
[0071] For the sake of clarity, it is pointed out that the invention is not limited to the embodiment variants shown, but can also encompass other configurations and designs.
Claims
1. A method for operating a laser source (4), in particular a pulsed laser source, for cutting, engraving, marking and / or inscribing a workpiece (7), wherein at least one laser source (4) is used in a housing (3) of a laser device (1) to process a workpiece (7), wherein the workpiece (7) is preferably placed on a processing table (9) and the workpiece (7) is processed line by line by moving a focusing unit (12) or a laser head (12), wherein: A control unit (13) generates a frequency signal (24) for controlling the laser light source (4) based on set parameters and / or loaded tasks (18), the frequency signal having a constant pulse repetition rate (26), in particular a frequency, or generates a control signal for laser pulses (25), the control signal having a constant pulse repetition rate (26), in particular a frequency, characterized in that at the beginning of a machining process or laser machining, in particular before each line (30) or path unit, the control unit (13) calculates the number (31) of laser pulses (25) for an image point / path unit (29), thereby generating a modulation signal (32) which releases the laser light source (4) for generating / applying laser pulses (25) at a constant pulse repetition rate (26) and applies the modulation signal to the laser light source (4), wherein the calculated number (31) of laser pulses (25) remains constant at other image points / path units (29).
2. The method according to claim 1, characterized in that The number (31) of the laser pulses (25) is calculated using the parameters of the image resolution (DPI, dots per inch), the movement speed and the pulse repetition rate (26) of the constant laser pulses (25).
3. The method according to claim 1 or 2, characterized in that The number (31) of laser pulses (25) per image point / path element (29) is calculated according to the formula "repetition rate / (resolution x movement speed) = number of laser pulses per image point / path element".
4. The method according to any one of the preceding claims, characterized in that As the movement speed parameter, a set target value is preferably used.
5. The method according to any one of the preceding claims, characterized in that The result of the number (31) of laser pulses (25) per pixel / path element (29) is always rounded, in particular rounded down.
6. The method according to any one of the preceding claims, characterized in that During acceleration (29a, b) and braking (29d) of the focusing unit (12) or laser head (12), the image points (29) have different lengths, in particular different durations or image point durations (34a-d), wherein the number (31) of the laser pulses (25) remains the same, in particular constant.
7. The method according to any one of the preceding claims, characterized in that A calculated modulation signal (32) for emitting the laser pulse (25) is applied to each pixel / path unit (29).
8. The method according to any one of the preceding claims, characterized in that When calculating the number (31) of laser pulses (25), further parameters for the grayscale mode, in particular grayscale parameters, are taken into account.
9. The method according to any one of the preceding claims, characterized in that In the grayscale mode, the new number (31) of the laser pulses (25) is calculated from the formula "(number 31 x grayscale fraction) rounded down = new number 31", wherein the grayscale fraction is formed from the formula "settable grayscale level / maximum grayscale level, in particular 256 8-bit grayscale", wherein each individual image point can be assigned its own grayscale fraction.
10. A laser plotter (1) for engraving, marking and / or inscribing a workpiece (7), comprising a processing space (8) for positioning the workpiece (7); at least one, but preferably two, laser sources (4) in the form of lasers (5, 6) with pulsating laser pulses (25), with corresponding deflection elements (11) and a preferably movable focusing unit (12), and a control unit (13) for controlling a carriage (14) driven preferably by a belt, with the focusing unit (12) being movably arranged thereon, characterized in that The control unit (13) is configured to calculate and apply a certain number of laser pulses to the focusing unit (12) or the laser head (12) according to any one of claims 1 to 9.