Method and marking device for applying a mark to an object

Abstract

The present invention relates to a method for applying a mark on an object based on image data, wherein the image data includes pixels having a first pixel value and pixels having a second pixel value, and wherein the mark to be generated includes a plurality of units, each unit corresponding to a pixel of the image data, wherein at least one light beam is emitted by a light-emitting component; a deflection direction of a scanning component for deflecting the light beam is scanned on the object; when the deflection direction points to a unit corresponding to a pixel having the first pixel value, the light-emitting component is activated to generate a mark in the unit; and when the deflection direction points to a unit corresponding to a pixel having the second pixel value, the light-emitting component is deactivated to keep the unit blank. The method is characterized in that the deflection direction is changed in a zigzag pattern for the units corresponding to the pixels having the first pixel value and in a straight-line movement for the units corresponding to the pixels having the second pixel value. The present invention also relates to a marking device for applying a mark on an object.

Description

Technical Field

[0001] In a first aspect, the present invention relates to a method for applying a mark on an object. In a second aspect, the present invention relates to a marking device. Background Art

[0002] In a general method for applying a mark on an object according to image data, wherein the image data includes pixels having a first pixel value and pixels having a second pixel value, and wherein the mark to be produced includes a number of units, each unit corresponding to a pixel of the image data, at least the following method steps are performed: emitting at least one light beam with a light-emitting component; scanning the deflection direction of a scanning component for deflecting the light beam on the object; when the deflection direction points to a unit corresponding to a pixel having the first pixel value, activating the light-emitting component to produce a mark in the unit; and when the deflection direction points to a unit corresponding to a pixel having the second pixel value, deactivating the light-emitting component to keep the unit blank.

[0003] Conventional marking devices are adapted to apply a mark on an object according to image data, wherein the image data includes pixels having a first pixel value and pixels having a second pixel value, and wherein the mark to be produced includes a number of units, each unit corresponding to a pixel of the image data. The marking device at least includes: a light-emitting component for emitting at least one light beam; a scanning component for deflecting the light beam, the scanning component being adapted to scan the deflection direction of the light beam on the object; and a control component, the control component being adapted to activate the light-emitting component to produce a mark in the unit when the deflection direction points to a unit corresponding to a pixel having the first pixel value, and being adapted to deactivate the light-emitting component to keep the unit blank when the deflection direction points to a unit corresponding to a pixel having the second pixel value.

[0004] Thus, on an object which can be of any kind or article or product, a mark corresponding to the image data is produced by irradiating the object with a light beam.

[0005] The first pixel value of the image data can, for example, indicate a black or dark pixel, while the second pixel value indicates a white pixel, and vice versa. In the following, these terms are not intended to limit the meaning of, for example, the first pixel value to a black pixel. Each pixel of the image data corresponds to a unit or field within the mark to be applied on the object. The term unit is used to refer to a specific area on the object. These areas correspond in their arrangement to the arrangement of the pixels in the image. The unit itself is not manufactured or drawn with the marking device, but the unit is filled with a mark or left blank, i.e., no mark is produced in the unit.

[0006] In principle, a cell can be filled with a single point generated by a light beam. However, when filling a larger cell with a large point, problems can occur. Since the light beam usually has a higher intensity at its center, a large point would require an inappropriate high light intensity at the center of that point. Therefore, in order to produce a mark corresponding to a single pixel, the relevant cell is not filled with just a single point. Instead, the cell is more filled with several points or one or more lines generated by the light beam. To this end, the light beam can be moved over the cell. For white pixels, when the laser beam is to be directed onto the corresponding cell, the corresponding cell remains blank or empty by deactivating the light-emitting component.

[0007] Generally, the pixels of the image data are arranged in one or more rows and one or more columns. Therefore, the corresponding cells constituting the mark are also arranged in one or more rows and one or more columns. The marks in the cells can also be referred to as printed pixels.

[0008] Marks such as two-dimensional barcodes (also known as data matrix codes, international data ID matrices or quick response QR codes) are widely used to mark items or products to encode best-before dates or general product information. Generally, a light-emitting component such as a laser is used to directly apply the mark to the product or label.

[0009] The information to be encoded can be, for example, text or numerical data. The length of the encoded data depends on the number of pixels in the image data of the mark. Error correction codes are usually used to increase the reliability so that the message can still be read even if one or more cells are unreadable.

[0010] The information to be marked is usually stored as image data with lines or rows and columns of pixels that encode the information. As more data is encoded in the mark, the number of pixels also increases. For example, the mark size varies from 10×10 to 144×144 according to the ECC 200 standard and from 9×9 to 49×49 according to the ECC 000-140 standard. Therefore, the marking of products involves the application of compressed information and is a time-consuming process.

[0011] In addition, in the production of items, these items usually move quickly, for example, on a conveyor belt. The marking of the product needs to be consistent with the speed at which the product moves. Therefore, the marking process needs to be fast. However, any distortion during the application of the mark, such as vibrations of the conveyor belt, can cause errors in the applied mark. This results in reduced readability.

[0012] In the prior art, it has been proposed to increase the total size of the mark. In this way, there are larger pixels, where distortion does not affect the readability of the mark either. However, in most applications, an enlarged mark is not applicable because there is only a limited amount of space, or only a specified area available for the mark on the product or label. Therefore, it is not possible to increase the size of the mark.

[0013] In addition, the prior art proposes to increase the error correction component of the mark. In this way, more information included in the mark is dedicated to correcting errors caused by damaged parts of the mark. In this way, the mark does not have to be increased in terms of overall size either. However, the mark carries less information because more pixels are used for error correction and fewer pixels are available for encoding the actual information. SUMMARY OF THE INVENTION

[0014] Accordingly, an object of the present invention is to provide a method and a marking device for applying a mark on an object, which are particularly fast in applying the mark and reduce the influence of distortion on the marking process.

[0015] The object of the present invention is solved by a method for applying a mark on an object according to image data and a marking device for applying a mark on an object according to image data.

[0016] In the following description, preferred embodiments are given, in particular in conjunction with the accompanying drawings.

[0017] According to the present invention, a method of the above kind is characterized in that the deflection direction is changed in a zigzag pattern for cells corresponding to pixels having a first pixel value and in a straight line movement for cells corresponding to pixels having a second pixel value.

[0018] According to the present invention, a marking device of the above kind is characterized in that the control component is adapted to change the deflection direction in a zigzag pattern for cells corresponding to pixels having a first pixel value and in a straight line movement for cells corresponding to pixels having a second pixel value.

[0019] Therefore, the core idea is that the scanning component is controlled to change its deflection direction in two different ways depending on whether the cell corresponding to a pixel having a first pixel value or a second pixel value is pointed at according to the deflection direction. For the first or dark pixel value for which the light beam is activated, the deflection direction moves in a zigzag shape, i.e., a wave-like pattern or waveform. For the second or bright pixel value for which the light beam is deactivated, the light beam moves in a straight line instead of zigzag to reach the next cell corresponding to the dark pixel as quickly as possible.

[0020] Advantageously, these combinations of movements result in a reduction in the time taken to produce the marking. One reason is that the deflection direction of the scanning member is moved only once and in the shortest possible way over the cells that are to be left blank. In contrast, other conventional patterns for scanning the invisible will cross such blank cells several times. Another reason for the time reduction is that the meandering pattern with relatively short longitudinal lines results in a narrow span of possible speeds of the scanning member. This in turn reduces the possible waiting time after a speed jump of the scanning member, which may occur when moving or skipping over blank cells. As a further advantage, the meandering or wavy shape is relatively stable against distortions such as vibrations or shocks to the object.

[0021] Advantageously, the aforementioned advantages could in principle already be achieved by reconfiguring the control unit of a conventional marking device to perform the present invention. In this way, there is no need to install or include new components in the device.

[0022] The deflection direction of the scanning member defines the irradiation area on the object onto which the light beam is directed or, in the case where the light-emitting member is deactivated, onto which the light beam would be directed. Among them, the meandering pattern in which the deflection direction is modified should be understood such that the irradiation area moves in a meandering pattern.

[0023] The meandering pattern can include any pattern having curved or straight lines with direction components of the same direction. These lines can be connected to or separated from each other. Preferably, at least some lines or portions of lines of the meandering pattern are parallel or anti-parallel to each other.

[0024] The linear movement for each second pixel value should be understood such that the scanning member moves the irradiation area over the cell corresponding to the second pixel value in the line, and if the laser beam is turned on, the laser beam will irradiate on the object in this irradiation area.

[0025] The marking to be produced can consist of or include several marks and blank areas. Each mark corresponds in position to a pixel of the image data having a first pixel value, and each blank area corresponds in position to a pixel having a second pixel value. The arrangement of the marks and blank areas is described via cells. The term "cell" is only used to denote a specific area on the object, however, the cell itself is not formed by any lines or rectangles.

[0026] Generally, the scanning member can be any member capable of moving to change the deflection direction. For this purpose, the scanning member can include one or more movable optical elements, such as mirrors or lenses, or one or more optical fibers that move translationally or rotate to adjust the deflection direction. Preferably, two galvanometer scanning mirrors are provided, which can rotate about different axes.

[0027] At least one light beam can be of any type as long as it is suitable for manipulating an object. Depending on the kind of object, in particular its material, different wavelengths and / or light intensities may be suitable. In order to mark various different objects, the light-emitting component can include several light units that emit light having different wavelengths and / or intensities. These light beams can be directed onto a common beam path and further directed to a scanning component. Alternatively or additionally, several light beams can be used simultaneously on different areas or at a common point on an object to generate a mark for increased light intensity, which can be used to generate different shades of color or gray scale.

[0028] For a focused high-intensity light beam, the light-emitting component can include at least one laser. The laser can be a continuous-wave laser or a pulsed laser. In the latter case, the marking within the unit is formed by a plurality of points that may or may not overlap each other. However, preferably, the marking is formed by a continuous line without interruption.

[0029] It can be understood that a straight-line movement of one or more units corresponding to pixels having a second pixel value causes the deflection direction of the scanning component to be adjusted in the shortest possible way to point to the next unit in which a mark is to be formed. If several units are to be left blank in a row, the straight-line movement can span these several units until, in the next unit corresponding to a pixel having a first pixel value, the meandering movement pattern of the deflection direction follows.

[0030] Preferably, the meandering pattern includes at least two longitudinal movements connected to a loop movement. During such movement, the light-emitting component can be activated without pause to generate a mark having at least two longitudinal lines connected to the loop, i.e., a mark in a meandering shape or pattern. Such a mark can be formed in each unit corresponding to a pixel having a first pixel value. The longitudinal lines are preferably straight lines.

[0031] The longitudinal movement and thus the longitudinal lines can be parallel or perpendicular to the column direction, i.e., the direction in which the units of a column are arranged. Alternatively, the longitudinal movement can be inclined or angled with respect to the column direction. In this case, the longitudinal movement has two direction components perpendicular to each other, where one direction component is parallel and the other direction component is perpendicular to the column direction. The larger component of the longitudinal movement can be along the column direction or perpendicular to the column direction. When referring to the direction of the longitudinal movement hereinafter, for an inclined longitudinal movement, this can be understood as the direction of the main component of the inclined longitudinal movement.

[0032] The meandering loop can have a straight-line shape or a circular shape at an angle to the longitudinal lines. Thus, the loop can form a U or V shape, or an open rectangle together with parts of the longitudinal lines. In a particularly preferred variant, the movement of the loop strongly overlaps with the longitudinal movement, resulting in a zigzag meandering shape, such as a shape of a sequence of Vs, i.e., VVVV.

[0033] The marks to be produced can be black and white or two-color images. Alternatively, the first pixel values can include subgroups of different pixel values, especially for marking gray or different shades of color. What all these pixel values have in common is that the light-emitting component is activated for marking these pixels and deactivated for marking pixels with the second pixel value.

[0034] The activation and deactivation of the light-emitting component can be understood as whether a light beam is sent onto the object via the scanning component and used to produce a mark. Thus, deactivation can also include the case where the light-emitting component continuously outputs a light beam, which is then blocked or directed elsewhere where it is not used to produce the aforementioned mark.

[0035] The image data can generally be given in any form. Pixels and pixel values may not exist in the image data from the start, but can be calculated from the image data and forwarded to the control unit. This may be the case for vector graphics or other instructions.

[0036] The pixels of the mark and thus the marked units are generally arranged two-dimensionally in rows and columns. The rows and columns can be perpendicular to each other, or in other ways or curved, or blurred or distorted, which may be beneficial for producing marks on curved surfaces, such as the label of a bottle. However, other configurations of the units are also possible. Preferably, the units can be directly adjacent to each other. Thus, the meandering shape of one unit can be continuous in directly adjacent units, without any gaps and irregularities in the meandering shape.

[0037] For good readability of the mark, the units with the mark should be filled to a high degree by the mark. For this purpose, the adjacent longitudinal lines of a mark preferably touch each other. In other words, in the direction perpendicular to the longitudinal lines, no free space is left between those lines.

[0038] Depending on the product and the desired appearance of the mark, it can also be advantageous if a small gap is left between adjacent longitudinal lines. This gap in the direction perpendicular to the longitudinal lines should be less than or equal to the width of the longitudinal lines, preferably less than or equal to half of the width. This further accelerates the marking process.

[0039] To fill the unit with the mark, the number of longitudinal lines within the unit can be equal to D divided by W, where D is the dimension or height of the unit in the direction perpendicular to the longitudinal lines and W is the width of the longitudinal lines.

[0040] If the cells form a pattern of rows and columns, then preferably the deflection direction is scanned column by column over the cells, and the marked longitudinal lines are formed in the direction of the rows, i.e., transversely or perpendicular to the direction in which the deflection direction advances from one cell to another within a column. In this way, the loop movement from one longitudinal movement to the next has caused the deflection direction to move towards the next cell to be marked. Thus, the meandering pattern itself constitutes a scanning movement through which the deflection direction is moved to the next cell.

[0041] Alternatively, the marked longitudinal lines are formed in the direction of the columns. Depending on the image and properties of the scanning member, this variant can result in a time reduction because during the longitudinal movement the speed of the scanning member can continue to reach the next cell without a change in direction and thus no deceleration is required.

[0042] Preferably, each mark formed in one of the cells corresponding to a pixel having a first pixel value has an even number of loops and thus an odd number of longitudinal lines. This can be advantageous when the marking process of a column is finished and the light beam has to be directed to the next column. In this case, an even number of loops often may result in the light beam not having to jump.

[0043] Alternatively, an odd number of loops for each mark can also be preferred. This can simplify the control algorithm of the control member; for the deflection direction after the meandering movement, it does not change in the direction of the longitudinal lines but only perpendicular to it, i.e., in the direction of the columns.

[0044] To further reduce the required time, the travel of the deflection direction within a column can be opposite to the travel within an adjacent column. Thus, when the deflection direction moves down in one column, it moves up in the next column. Both the down and up movements can be achieved by meandering loop movements and straight movements during which no marking is produced, while the meandering longitudinal movement can be perpendicular to the down and up movements.

[0045] The column-by-column scanning movement can be understood as scanning only the cells within one column and then continuing to the next column. In an alternative variant of the column-by-column movement, the deflection direction advances from one cell to another within the first column; however, before the deflection direction advances to the next cell within the first column, two or more adjacent cells in the same row, each associated with the first pixel value, can be scanned. As a result, at least one meandering pattern spans the adjacent cells corresponding to the pixels having the first pixel value such that all the longitudinal lines of the mark produced with this meandering pattern span these cells, while each loop is formed only in one of these adjacent cells. In this way, a smaller number of loops is required for the entire marking. Since each loop is connected to the decelerating scanning member and the accelerating scanning member in different directions, the reduction in the number of loops results in a reduced time required to produce the mark.

[0046] Such a meandering shape spanning several cells is also advantageous when the direction of the longitudinal lines is mainly in the direction along the columns.

[0047] According to the application of the present invention, the meandering shape of the marking can be considered detrimental to the readability of the marking. To avoid this problem, the meandering pattern for changing the deflection direction includes at least two longitudinal movements connected to the loop movement, and the light-emitting component is activated only during the longitudinal movement, but not during the loop movement, to generate a marking having at least two longitudinal lines. Thus, these lines are not connected to the loop. However, the movement of the scanning component is not affected by this variant and still results in a meandering pattern of the deflection direction. Therefore, the activation of the light-emitting component of the cells corresponding to the first pixel value should not be understood as continuous, but as having interrupted activation. This embodiment of the present invention can be combined with the other variants described, except that the light-emitting component is deactivated during the loop movement.

[0048] In a further embodiment, the meandering pattern includes a zigzag, wherein the resulting marking includes a number of lines, and adjacent lines are inclined with respect to each other. An angle of preferably 5 to 25 degrees can be formed between adjacent lines. In the zigzag, one line and the next line except one can be parallel to each other. In such a meandering pattern for the deflection direction, only one velocity component changes, while the other velocity component perpendicular thereto remains constant, which results in a zigzag. This can simplify the setup and / or result in a reduced marking time.

[0049] In column-by-column scanning, when all cells corresponding to the first pixel value of the previous column have been marked, the deflection direction turns to the next column. In some cases, the light-emitting component can remain activated in this case, which enables better use of time when generating the marking. This can be achieved if a marking has been generated in the last cell of a column such that the marking ends adjacent to the next cell of the adjacent column, and if the next cell corresponds to a pixel having the first pixel value. In this case, the light-emitting component can remain activated when the deflection direction moves from the last cell to the next cell. This is explained in detail below: The first column can be scanned from top to bottom. Then, the next column can be scanned from bottom to top. The marking generated with a meandering pattern in the lowest cell of the first column can start, for example, at the upper left corner of the cell, continue in a meandering manner, and end at the lower right corner of the cell. If the next column is to the right of the first column, the right lower end of the marking in the lowest cell of the first column directly abuts the next cell to be marked. Thus, the meandering pattern can continue in the next cell without interruption of the light beam emission. In the next cell, the meandering pattern starts at the lower left corner of the cell, continues upward in a meandering shape, and ends at the upper right corner.

[0050] The indicated movement and direction should be understood relative to the object. However, the object itself can move, for example, on a conveyor belt. Therefore, the zigzag shape and the other described movements are superimposed on the movement of the object. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] A better understanding of the present invention, as well as various other features and advantages of the present invention, will become more readily apparent by reference to the following description of the schematic drawings, which are shown by way of example only and not by way of limitation, in which like reference numerals may represent like or substantially like components:

[0052] FIG. 1 shows a marker according to a first prior art;

[0053] FIG. 2 shows in detail the printed pixels according to the first prior art;

[0054] FIG. 3 shows a marker according to a second prior art;

[0055] FIG. 4 shows a schematic diagram of forming a marker according to the second prior art;

[0056] Figure 5 Details of the marker and the moving beam according to a first embodiment of the present invention are shown;

[0057] Figure 6 Details of the marker and the moving beam according to a second embodiment of the present invention are shown;

[0058] Figure 7 Details of the marker and the moving beam according to a third embodiment of the present invention are shown;

[0059] Figure 8 Details of the marker and the moving beam according to a fourth embodiment of the present invention are shown. DETAILED DESCRIPTION

[0060] FIG. 1 shows a first prior art for forming a marker 1, also referred to as dot pattern formation. The marker corresponds to image data having pixels arranged in rows and columns. Therefore, the marker is also composed of units 2, 2a arranged in rows or lines 3 and columns 4. Each unit 2 corresponds to a pixel, which can have a first pixel value or a second pixel value, for example, a dark or bright pixel. If the unit 2 corresponds to the first pixel value, it is filled with a marker 5, or if it corresponds to the second pixel value, it remains blank, as shown by the unit 2a. In the case of a marker on, for example, food or beverage, the marker can contain information such as a best before date or general information about ingredients or the like.

[0061] Figure 2 shows in detail four adjacent markers 5, i.e., four adjacent cells, each cell being filled with a marker 5. According to the first prior art, the light beam moves in a spiral shape, generating a single point along the spiral to form each pixel 5. The path indicating the deflection direction of the scanning component is represented by a thick line and is used to continue from one cell to the next. During this movement, the light-emitting component is typically deactivated, i.e., the thick line is not part of the marker. This technique belongs to the per-cell rendering method. However, it is quite time-consuming.

[0062] Figure 3 shows a second prior art method of forming a marker 1. The details of this figure are shown enlarged in Figure 4. According to the second prior art method, the light beam moves along line 6 over the entire area of the marker. The light beam moves not just once along a column but three times. In this way, the marker generated in one cell 2 (indicated by the dashed box) consists of three lines adjacent to each other, thus producing a roughly square shape. The cell 2a to be kept blank is also scanned three times, where the light-emitting component is deactivated.

[0063] When the deflection direction passes through the cell to be kept blank, the scanning component typically accelerates to a higher scanning speed. When it reaches the cell where a marker is to be generated, the scanning speed is reduced again. In these cases, additional waiting time is added to allow unwanted vibrations to disappear. This again results in a longer marking time. The total time for generating the marker is also not satisfactory and is generally even higher than the time requirements of the method described in connection with Figures 1 and 2.

[0064] The present invention allows for faster marker generation. Referring to Figure 5 An example of the method of the present invention is described, which shows the marker 1 and auxiliary lines that are not part of the marker but can be used to explain the method.

[0065] Again, a marker 1 corresponding to the image data is formed. The image data includes pixels having a first pixel value (which corresponds to the marker 5 to be generated in cell 2) and a second pixel value (corresponding to the empty cell 2a without a marker). The cell 2 corresponding to the first pixel value is shown as a square grid, and the cell 2a corresponding to the second pixel value is left blank. One blank cell 2a is represented by a rectangular box.

[0066] The light beam scans over the marker area to generate the marker 1. In the area to be left blank, the light beam is deactivated. This scanning movement is performed using a scanning component with a variable deflection direction for the light beam. Figure 5 The path of the deflection direction 10 is shown, i.e., the areas successively pointed to by the deflection direction. The main idea of the present invention lies in the shape of this path and in using two different shapes depending on whether the deflection direction points to the cell 2 where a marker 5 is to be generated or to the cell to be left blank.

[0067] At the start of the marking process, the deflection direction points to position 11, for example, the upper left corner of the first cell in the first column. This cell corresponds to the first pixel value, and thus a mark is to be produced in this cell. Accordingly, the light-emitting component is activated. The deflection direction and thus the light beam move in a meandering pattern within the cell. That is, the deflection direction moves to the right to produce a longitudinal line, then moves down to produce a loop portion, and then moves left to produce another longitudinal line. Next within the cell are other loops and longitudinal lines.

[0068] In the example shown, all the cells in the first column correspond to the first pixel value. Thus, when continuing to scan the next cell in the first column, the light-emitting component remains activated. In this way, the light beam meanders downwards and produces a meandering mark in each of these cells. After the first column is completed, the deflection direction moves from position 12 to position 13, which is the starting point in an adjacent cell of the next column. During this movement, no light beam is emitted. Starting from position 13, the meandering movement continues upwards along the column until reaching cell 2a which is to be left blank. Now the light beam is turned off, and instead of the meandering pattern, the deflection direction moves along a straight line 8 to reach the next cell, where the light beam is turned on and then follows the meandering pattern. When the scanning of this column ends at point 15, the next column (to the right) is then scanned. Since point 15 is in direct contact with the cell of the next column, compared to the jump from point 12 to point 13, there is no need to turn off the light beam.

[0069] The distance between the longitudinal lines in a cell 2 is preferably chosen to correspond to the thickness or width of a line; in this way, no gap is left between the said lines.

[0070] The instructions for inputting such a meandering pattern into the control unit can be represented as follows, especially when starting at point 11:

[0071] - Step A) Move the deflection direction in the row direction up to equal to the cell width minus one light beam width by subtracting the light beam width. The resulting line has a length equal to the cell width (i.e., the dimension of the cell in the row direction); in this way, a longitudinal line starting from point 11 is produced;

[0072] - Step B) Move up to (cell height minus light beam width) divided by (number of longitudinal lines per cell minus one) in the row direction; the cell height minus the light beam width represents the distance from the center of the first longitudinal line to the last longitudinal line to be produced in the cell; this distance will be divided by the number of steps in the row direction, and the number of steps is one less than the number of longitudinal lines per cell;

[0073] - Now repeat steps A) and B), but where each pair of consecutive longitudinal lines meet each other, especially anti-parallel, until reaching the end of the said cell after step A).

[0074] - If the next cell is also to be filled with a mark now, continue with the previous steps. Otherwise, the next is a straight movement in the row direction until the next cell to be filled with a mark is reached or until the end of the column is reached.

[0075] - When the end of the column is reached, deflect the direction to the next column, and that column and any subsequent columns are processed in the aforesaid manner until the entire mark is produced.

[0076] Generally, the mark is larger than Figure 5 the mark shown in

[0077] Refer to Figure 6 for a description of another embodiment of the present invention. Figure 6 It is different from Figure 5 in the shape of the zigzag pattern. In Figure 6 , the zigzag starts again from a longitudinal line. However, this line is not perpendicular to the row direction 4 but at another angle thereto. Thus, this line has a component in the row direction and a component in the column direction. In addition, this line is slightly curved to travel in the row direction. This zigzag loop is formed by reversing the speed of the movement component in the row direction; the movement component in the column direction remains constant.

[0078] In Figure 7 , another embodiment of the present invention is shown. In this case, the zigzag includes straight lines having a component in the row direction and a component in the column direction. Each second straight line is parallel to each other.

[0079] Figure 8 shows a further variant of the present invention. The zigzag movement of the deflection direction is the same as that described with reference to Figure 5 . However, the light-emitting component is only activated during the movement of the longitudinal line, and is not activated during the loop movement, i.e., during the movement in the row direction. As a result, the mark produced in one cell 2 consists of several longitudinal lines that are not connected to each other.

[0080] The method and the marking device according to the present invention allow for quickly, effectively and with a reduced possibility of distortion forming a mark 1 on an object. In particular, the method does not have as much delay time as the prior art and can thus be performed faster. By selecting the width of the light beam, a high-quality mark 1 with particularly high readability can be formed.

Claims

1. A method for applying a mark on an object according to image data, Among them, wherein the image data includes pixels having a first pixel value and pixels having a second pixel value, and wherein the mark to be generated includes a plurality of units, each unit corresponding to a pixel of the image data, wherein: - at least one light beam is emitted by a light-emitting component, - the deflection direction of a scanning component for deflecting the light beam is scanned on the object, - when the deflection direction points to a unit corresponding to a pixel having a first pixel value, the light-emitting component is activated to generate a mark in the unit, and - when the deflection direction points to a unit corresponding to a pixel having a second pixel value, the light-emitting component is deactivated to keep the unit blank, where the deflection direction is changed, - in a zigzag pattern, for the units corresponding to pixels having a first pixel value, and - in a straight-line movement, for the units corresponding to pixels having a second pixel value, where the zigzag pattern starts and ends at the boundary of the unit.

2. The method according to claim 1, characterized in that the zigzag pattern includes at least two longitudinal movements movably connected to a loop to generate a mark having at least two longitudinal lines connected to the loop.

3. The method according to claim 2, where adjacent longitudinal lines of a mark are in contact with each other.

4. The method according to claim 1, where To fill the cell with marks, the number of vertical lines in the cell is equal to D / W, where, D is the dimension of the unit in a direction perpendicular to the longitudinal line, and W is the width of the longitudinal line.

5. The method according to claim 2, where the units form a pattern of rows and columns, the deflection direction is scanned column by column on the units, and the longitudinal lines of the mark are formed in the row direction.

6. The method according to claim 2, where the units form a pattern of rows and columns, the deflection direction is scanned column by column on the units, and the longitudinal lines of the mark are formed in the column direction.

7. The method according to claim 1, where each mark formed in one of the units corresponding to a pixel having a first pixel value has an even number of loops.

8. The method according to claim 2, where if a mark has been created in the last unit of a column such that the mark ends adjacent to the next unit of the adjacent column, and if the next unit corresponds to a pixel having a first pixel value, the light-emitting component remains activated while the deflection direction moves from the last unit to the next unit.

9. The method according to claim 1, where at least one zigzag pattern spans adjacent units corresponding to pixels having a first pixel value such that all longitudinal lines of the mark generated with the zigzag pattern span these units, while each loop is formed only in one of these adjacent units.

10. The method according to claim 1, where the zigzag pattern includes at least two longitudinal movements movably connected to a loop movement, and the light-emitting component is activated only during the longitudinal movements and not during the loop movement to generate a mark having at least two longitudinal lines.

11. The method according to claim 1, where The zigzag pattern includes a zigzag, wherein, the generated mark includes a plurality of lines, wherein adjacent lines are inclined to each other.

12. A marking device for applying a mark on an object according to image data, Among them, The image data includes pixels having a first pixel value and pixels having a second pixel value, and wherein the mark to be generated includes a number of units, each unit corresponding to a pixel of the image data, the marking device comprising: - a light-emitting component for emitting at least one light beam, - a scanning component for deflecting the light beam, the scanning component being adapted to scan the deflection direction of the light beam on the object, and - a control component adapted to activate the light-emitting component to generate a mark in the unit when the deflection direction points to the unit corresponding to the pixel having the first pixel value, and to deactivate the light-emitting component to keep the unit blank when the deflection direction points to the unit corresponding to the pixel having the second pixel value, wherein the control component is adapted to change the deflection direction, - in a meandering pattern, for the units corresponding to the pixels having the first pixel value, and - in a straight-line movement, for the units corresponding to the pixels having the second pixel value, where the meandering pattern starts and ends at the boundary of the unit.

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