Method for imaging a mask layer and associated imaging system - Patents.com

Abstract

1. A method for imaging a mask layer, comprising the steps of: reading out imaging data of a sequence of at least (C1+C2) pixels; using a first group of imaging beams of C1 for substantially simultaneously imaging a first group of C1 pixels of the sequence in accordance with the imaging data at a first time point; using a second group of imaging beams of C2 for substantially simultaneously imaging a second group of C2 pixels of the sequence in accordance with the imaging data at a second time point; and repeating the steps of reading out the imaging data, using the first group of imaging beams of C1 for imaging at the first time point, and using the second group of imaging beams of C2 for imaging at the second time point for a next sequence of at least (C1+C2) pixels.

Description

[Technical field]

[0001] The field of the invention relates to imaging a mask layer in the field of printing technology. Various embodiments herein relate to a method for imaging a mask layer, a control module and a computer program for use in imaging a mask layer, as well as a method and a system for imaging and exposing a relief master. [Background technology]

[0002] In known methods for imaging a mask layer, imaging data provides information about pixels. The imaging beam then ablates the mask layer based on this information about the pixels. Given the complexity of the pixels, spots on the mask layer may be ablated individually. This is a time-consuming process.

[0003] In addition, during imaging of the mask layer, what is in the imaging data needs to be translated into beam settings. The correspondence between the imaging data and the beam settings may, for example, be found at each point in time after the imaging data is provided. However, this is computationally intensive.

[0004] Furthermore, it is often necessary to image the mask layer under multiple settings to generate different regions on the mask layer. This may mean, for example, providing multiple separate sets of imaging data for the same mask layer. These different sets of imaging data must be interpreted separately by the control module before they can be used to direct the beam to ablate spots on the mask layer. Examples of methods and systems for processing raster image files to obtain control data for controlling settings of an imaging device are disclosed in WO 2021 / 110831 in the name of the applicant. Furthermore, EP 1 674 930 discloses a method for preventing stitching in multi-beam imaging. JP 2017-154301 A discloses a flexographic printing plate that can reduce matte surface printing defects that occur near the boundary between small dots in the matte area and the net point area in flexographic printing, and can achieve uniform small highlight dots that correspond to the highlight gradation of the printed image on the printed matter. Summary of the Invention

[0005] Some embodiments of the present disclosure relate to methods that can image a mask layer more efficiently while maintaining ablation accuracy. Some embodiments of the present disclosure relate to methods that can simplify the conversion of imaging data into instructions for a beam. Some embodiments of the present disclosure relate to methods that allow imaging data to control a beam in multiple settings while reducing the complexity of converting the imaging data into ablation instructions.

[0006] According to a first aspect of the present disclosure, there is provided a method for imaging a mask layer, comprising the steps of: - providing a mask layer, - reading out imaging data of a sequence of at least (C1+C2) pixels, C1 and C2 being integers greater than or equal to 1; - using a group of C1 first imaging beams for substantially simultaneously imaging a first group of C1 pixels of said sequence according to the read-out imaging data at a first time point, - at a second point in time, using a group of C2 second imaging beams for substantially simultaneously imaging a second group of C2 pixels of said sequence according to the read-out imaging data, - optionally, at one or more subsequent time points, using a subsequent group of imaging beams for substantially simultaneously imaging a subsequent group of pixels according to the read-out imaging data, said pixels of said subsequent group being different from the pixels of the first group and the second group; - repeating the steps of reading out the imaging data, using a first group of imaging beams C1 for imaging at a first time point, using a second group of imaging beams C2 for imaging at a second time point, and optionally using a subsequent group of imaging beams for imaging at one or more subsequent time points for a next sequence of at least (C1+C2) pixels. A method comprising:

[0007] Thus, a plurality of at least (C1+C2) distinct imaging beams are arranged next to each other, including a first group (L1) of imaging beams of C1 and a second group (L2) of imaging beams of C2. The imaging beams are distinct in the sense that the beams of the first group do not overlap or correspond to the beams of the second group. By organizing the pixels into at least two groups and imaging the pixels using the groups of beams, a compromise between printing speed and accuracy can be found.

[0008] The first aspect of the present disclosure may include any one of the following features or any technically possible combination of the following features.

[0009] - C1 and C2 are integers greater than or equal to 2, and the C1 pixels of the first group are selected such that at least two pixels of the first group are separated by at least one pixel that does not belong to the first group, and the C2 pixels of the second group are selected such that at least two pixels of the second group are separated by at least one pixel that does not belong to the second group.

[0010] In this embodiment, a significant number of pixels can be imaged simultaneously. Thus, the process of imaging the mask layer is simplified and accelerated. In addition, by separating at least two pixels in the first group and at least two pixels in the second group by a pixel(s) that does not belong to each group, the interference between the pixels of the groups can be reduced, and imaging is easier to control.

[0011] -C1=C2=C, and each sequence contains N*C pixels, where N is an integer greater than or equal to 2.

[0012] Having the same number of pixels in each group simplifies the process of imaging the mask layer.

[0013] - the method further includes providing a clock having a first frequency f1, wherein a period between subsequent time points corresponds to 1 / f1, and reading out imaging data of at least (C1+C2) pixels includes reading out imaging data of C1 pixels and then, after an interval of 1 / f1, reading out imaging data of C2 pixels.

[0014] In this particular embodiment, each group of pixels is read out in turn, with the first group of pixels being read out as a first step, followed by the second group of pixels being read out as a second step.

[0015] The C pixels in the nth group, where n is an integer and 1≦n≦N, include the nth pixel, the (n+N)th pixel, the (n+2*N)th pixel, etc. of the sequence of N*C pixels.

[0016] In this particular embodiment, the pixels in the nth group are equally spaced. This regular spacing makes it easier to read out the corresponding imaging data and / or image the group of pixels.

[0017] the sequence corresponds to a single row in the imaging data, or the sequence corresponds to portions of different rows in the imaging data, preferably the C pixels in the nth group include the nth pixel in the mth row, the (n+N)th pixel in the (m+1)th row, the (n+2*N)th pixel in the (m+2)th row, ..., where 1≦m≦N and m is an integer.

[0018] If the sequence corresponds to a single row in the imaging data, the readout of the first and second groups of pixels is easy to implement. If the sequence corresponds to different rows in the imaging data, it becomes possible to compensate for the movement of the mask layer when different groups of pixels are imaged, so that pixels belonging to different rows may nevertheless be imaged on a straight line, in particular a line perpendicular to the direction of movement of the mask layer.

[0019] - the method includes obtaining a first set of imaging settings for a first group of C1 pixels and substantially simultaneously imaging the first group of C1 pixels according to the first set of imaging settings, obtaining a second set of imaging settings for a second group of C2 pixels and substantially simultaneously imaging the second group of C2 pixels according to the second set of imaging settings, wherein for each group of pixels the set of imaging settings is different.

[0020] By using different imaging settings for each group of pixels, different imaging results can be obtained for each group of pixels, distinct from other groups of pixels.

[0021] - the method includes, wherein obtaining the first set of imaging settings or the second set of imaging settings includes searching for an imaging setting in a lookup table based on a set of bit values ​​of image data corresponding to the first group or the second group of pixels, respectively.

[0022] By using a lookup table, the correspondence between the imaging data and the beam settings can be determined and fixed before the layer is masked and imaged, so that when imaging a pixel, it may be possible to simply refer to the lookup table without any additional calculations.

[0023] A set of bit values ​​includes, for each pixel, either a "1" if the pixel is an imaging pixel, or a "0" if the pixel is a non-imaging pixel.

[0024] The set of bit values ​​includes two or more bit values ​​for each pixel.

[0025] By having more than one bit value per pixel, more possible settings are available for each pixel in the image file, and therefore a greater variety of imaged pixels can be obtained from one single image file.

[0026] The first set of imaging settings and the second set of imaging settings respectively include an imaging setting of C1 for a first imaging beam of C1 and an imaging setting of C2 for a second imaging beam of C2.

[0027] each set of imaging settings specifies values ​​that represent the size and / or shape and / or position of the imaged spot corresponding to the imaging pixel, preferably the first set of imaging settings and the second set of imaging settings specify the following parameters: the intensity value used to generate the imaged feature corresponding to the imaging pixel, e.g., the intensity value for controlling the beam used for imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for imaging; beam diameter and / or beam shape values ​​for controlling the beam used for imaging; · the number of passes used for imaging, Indication of which of a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to a pixel or group of pixels for imaging. Define one or more of the following:

[0028] - all pixels in the first group are separated by at least one pixel that does not belong to the first group, and all pixels in the second group are separated by at least one pixel that does not belong to the second group.

[0029] Because all pixels in the first and second groups are separated by pixels that do not belong to the respective groups, interference between pixels within each group is further reduced.

[0030] - The mask layer is moved in a movement direction (M) relative to the imaging beam while a first group of C1 pixels and a second group of C2 pixels, as well as subsequent groups of pixels, if present, are imaged.

[0031] This embodiment allows uninterrupted imaging of different groups of pixels positioned next to each other in the direction of movement.

[0032] - the mask layer is rotating on the drum while a first group of C1 pixels and a second group of C2 pixels, and subsequent groups of pixels, if present, are imaged, the direction of movement (M) corresponding to the direction of rotation of the drum, which is typically the case in an external drum configuration where the mask layer is wrapped around the outer surface of the drum.

[0033] - the mask layer is moving on the flat bed table and / or the imaging beam is moving along the flat bed table, while a first group of C1 pixels and a second group of C2 pixels, and subsequent groups of pixels, if present, are imaged, and the direction of movement (M) corresponds to the longitudinal direction of the flat bed table.

[0034] - a mask layer is positioned on the inner surface of the drum, and the mask layer is rotated relative to the imaging beam while a first group of C1 pixels and a second group of C2 pixels, and subsequent groups of pixels, if present, are imaged, the direction of movement (M) corresponding to the direction of rotation of the mask layer or the imaging beam. This is typically the case for an inner drum configuration, where the mask layer is positioned on the inner surface of the drum.

[0035] Each of these three embodiments corresponds to a particular situation: one where the mask layer is wrapped onto the outer surface of the drum, another where the mask layer is positioned on a flat bed table, and a third where the mask layer is positioned on the inner surface of the drum.

[0036] - the first group of imaging beams and the second group of imaging beams, and if present, any subsequent groups of imaging beams, are arranged adjacent to one another and are aligned along a line when the groups of imaging beams are observed perpendicular to the mask layer, said line defining an angle with a lateral direction (T) perpendicular to the direction of movement (M), the angle compensating for movement of the mask layer between the first and second time points.

[0037] Thanks to this arrangement, it is possible to image pixels aligned in the laterally perpendicular direction to the movement direction without any additional adjustment due to the movement in the movement direction, even if the mask layer moves in the movement direction.

[0038] - moving the imaging beam relative to the mask layer in a lateral direction (T) perpendicular to the direction of movement, such that the imaging beam moves relative to the mask layer in the lateral direction over at least (C1+C2) pixels.

[0039] This embodiment allows imaging of additional pixels next to the (C1+C2) pixel in the lateral direction of the drum and / or flatbed table.

[0040] - the movement in a lateral direction (T) perpendicular to the direction of movement (M) is substantially continuous;

[0041] The continuous lateral movement allows imaging additional pixels adjacent to the (C1+C2) pixel in the lateral direction without any interruption.

[0042] According to a second aspect of the present disclosure, there is provided a method for imaging a mask layer, comprising the steps of: - providing a mask layer, - providing a look-up table having a number of imaging settings depending on a bit sequence; - reading out imaging data for a plurality of pixels; - deriving an imaging setting from a lookup table based on a bit sequence of imaging data corresponding to a plurality of pixels; - using a plurality of imaging beams to image a plurality of pixels substantially simultaneously according to the acquired imaging settings. A method comprising:

[0043] Thanks to this method, it is possible to simply find the correspondence between the imaging data and the beam instructions in the look-up table without performing any additional calculations, thus making the process of imaging the mask layer much simpler.

[0044] The second aspect of the present disclosure may include any one of the following features or any technically possible combination of the following features.

[0045] A set of bit values ​​includes, for each pixel, a "1" if the pixel is an imaging pixel, and a "0" if the pixel is a non-imaging pixel.

[0046] The set of bit values ​​includes at least two bit values ​​for each pixel.

[0047] Having two bit values ​​per pixel makes it possible to obtain multiple settings of the imaging beam based on one single image file.

[0048] The imaging settings include multiple separate and independent values ​​for multiple imaging beams.

[0049] In this embodiment, each imaging beam can image a pixel independently of the other imaging beams.

[0050] Each imaging setting specifies values ​​that represent the size and / or shape and / or position of the imaged spot corresponding to an imaging pixel, preferably the imaging settings are the following parameters: the intensity value used to generate the imaged feature corresponding to the imaging pixel, e.g., the intensity value for controlling the beam used for imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for imaging; beam diameter and / or beam shape values ​​for controlling the beam used for imaging; · the number of passes used for imaging, Indication of which of a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to a pixel or group of pixels for imaging. Define one or more of the following:

[0051] - reading out the imaging data includes reading out imaging data of a sequence of at least (C1+C2) pixels, where C1 and C2 are integers greater than or equal to 1; obtaining the imaging settings includes obtaining a first imaging setting based on a plurality of first bit values ​​corresponding to C1 pixels of the sequence and a second imaging setting based on a plurality of second bit values ​​corresponding to C2 pixels of the sequence; and using the plurality of imaging beams for imaging; using a C1 first group of imaging beams to substantially simultaneously image a C1 first group of pixels of the sequence according to a first imaging setting at a first time point; using a C2 second group of imaging beams to substantially simultaneously image a C2 second group of pixels of said sequence according to a second imaging setting at a second time point; Optionally, at one or more subsequent time points, using a subsequent group of imaging beams to substantially simultaneously image a subsequent group of pixels according to the read-out imaging data, wherein the pixels of the subsequent group are different from the pixels of the first group and the second group. Including, The method further includes repeating the steps of reading out the imaging data, obtaining the imaging settings from the lookup table, and using the multiple imaging beams for imaging a next sequence of at least (C1+C2) pixels.

[0052] - C1 and C2 are integers greater than or equal to 2, and the C1 pixels of the first group are selected such that at least two pixels of the first group are separated by at least one pixel that does not belong to the first group, and the C2 pixels of the second group are selected such that at least two pixels of the second group are separated by at least one pixel that does not belong to the second group.

[0053] -C1=C2=C, and each sequence contains N*C pixels, where N is an integer greater than or equal to 2.

[0054] The C pixels in the nth group, where n is an integer and 1≦n≦N, include the nth pixel, the (n+N)th pixel, etc. of the sequence of N*C pixels.

[0055] the sequence corresponds to a single row in the imaging data, or the sequence corresponds to portions of different rows in the imaging data, preferably the C pixels in the nth group include the nth pixel in the mth row, the (n+N)th pixel in the (m+1)th row, the (n+2*N)th pixel in the (m+2)th row, ..., where 1≦m≦N and m is an integer.

[0056] According to a third aspect of the present disclosure, there is provided a method for imaging a mask layer, comprising the steps of: - providing a mask layer, - reading out imaging data for a plurality of pixels; - obtaining an imaging setting based on a sequence of bit values, the sequence including at least two bit values ​​for each pixel of the plurality of pixels; - using a plurality of imaging beams to image a plurality of pixels substantially simultaneously according to the acquired imaging settings. A method comprising:

[0057] By having at least two bit values ​​per pixel, one set of imaging data can control the imaging beam under at least two settings per pixel, thereby allowing multiple variations of each pixel to be obtained from a single image file.

[0058] The third aspect of the present disclosure may include any one of the following features or any technically possible combination of the following features.

[0059] The imaging settings include multiple separate and independent values ​​for multiple imaging beams.

[0060] Each imaging setting specifies values ​​that represent the size and / or shape and / or position of the imaged spot corresponding to an imaging pixel, preferably the imaging settings are the following parameters: the intensity value used to generate the imaged feature corresponding to the imaging pixel, e.g., the intensity value for controlling the beam used for imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for imaging; beam diameter and / or beam shape values ​​for controlling the beam used for imaging; · the number of passes used for imaging, Indication of which of a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to a pixel or group of pixels for imaging. Define one or more of the following:

[0061] Some embodiments of the present disclosure relate to the above-mentioned method, wherein a mask layer is provided on the photopolymerizable layer of the relief master, and after imaging, the photopolymerizable layer of the relief master is exposed through the mask layer and the relief master is developed to obtain the relief structure. The mask layer may be an integral part of the relief master or may be a separate article that is attached to the relief master prior to exposure to electromagnetic radiation.

[0062] Some embodiments of the present disclosure relate to a relief structure obtained by the above-mentioned method.

[0063] Some embodiments of the present disclosure relate to a computer program comprising computer-executable instructions that, when the program is run on a computer, control an embodiment of the method described above in relation to any one of the aspects of the present disclosure.

[0064] Some embodiments of the present disclosure relate to a digital data storage medium encoding a machine-executable program of instructions for performing any one of the method steps described above in relation to any one of the aspects of the present disclosure.

[0065] Some embodiments of the present disclosure relate to a computer program product comprising computer-executable instructions for controlling or executing the methods described above in relation to any one of the above-mentioned aspects of the present disclosure when the program is executed on a computer.

[0066] Some embodiments of the present disclosure relate to a control module configured to perform the methods described above in relation to any one of the above-mentioned aspects of the present disclosure.

[0067] Some embodiments of the present disclosure relate to a system for processing a relief master comprising an imager configured to image a mask layer, and a digital data storage medium as described above and / or a control module as described above for controlling the imager. Optionally, the system further comprises any one or more of the following: at least one transport system configured to transport the relief master, a storage device, an exposure means configured to expose the relief master through the imaged mask layer, a development means configured to remove at least a portion of unexposed material from the relief master, a drying system, a post-exposure device, a cutting device, a mounting station, a heater.

[0068] Another embodiment of the present disclosure relates to a mask layer obtained by the above-mentioned method.

[0069] Any feature of the first aspect of the present disclosure may be combined with any feature of the second and / or third aspect of the present disclosure.

[0070] The above-mentioned and further aspects of the disclosure are explained in more detail below on the basis of several embodiments which are illustrated with reference to the attached drawings. [Brief description of the drawings]

[0071] [Figure 1] 1 is an exemplary embodiment of a system for imaging a mask layer having two groups of pixels with three pixels per group. [Diagram 2] Different steps are described at different times during imaging of a mask layer in an exemplary embodiment. [Diagram 3] 1 illustrates an exemplary embodiment of a lookup table. [Figure 4] The amplitude of the laser beam is shown in four sequences of bit values ​​including two bit values ​​per pixel, where the two bit values ​​have been converted to one bit values. [Diagram 5]The amplitude of the laser beam is shown in four sequences of bit values ​​including two bit values ​​per pixel, where the two bit values ​​have been converted to one bit values. [Figure 6] The amplitude of the laser beam is shown in four sequences of bit values ​​including two bit values ​​per pixel, where the two bit values ​​have been converted to one bit values. [Figure 7] The amplitude of the laser beam is shown in four sequences of bit values ​​including two bit values ​​per pixel, where the two bit values ​​have been converted to one bit values. [Figure 8] 1 illustrates another exemplary embodiment of a system for imaging a mask layer having three groups of pixels with two pixels per group. [Figure 9] FIG. 1 is a schematic diagram of an exemplary embodiment of a system for generating a relief structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0072] Flexography or letterpress printing is a technique commonly used for mass printing. A flexographic or letterpress printing plate is a relief plate with printing elements, typically called reliefs or dots, protruding above the non-printing elements to produce an image on a recording medium such as paper, cardboard, film, foil, laminate, etc. Also, cylindrical shaped printing plates or sleeves may be used.

[0073] There are various methods for making flexographic or letterpress printing plate precursors. According to conventional methods, flexographic or letterpress printing plate precursors are made from a multilayer substrate comprising a backing layer and one or more photohardening layers (also called photosensitive layers). These photohardening layers are hardened by exposure to electromagnetic radiation through a mask layer containing image information, or by direct and selective exposure to electromagnetic radiation, for example by scanning the plate to transfer image information to obtain a relief plate. After hardening, the unhardened parts are removed either by using a liquid capable of dissolving or dispersing the unhardened material, or by a thermal treatment that liquefies and removes the unhardened material. The removal of the liquefied material can be achieved by attachment or adsorption to a developer material, or by irradiation of a beam on a solid, liquid, or gas that can be heated. An alternative is to remove the material in the non-printing areas by ablation using a high-power laser beam.

[0074] In flexographic or letterpress printing, ink is transferred from a flexographic plate to a printing medium. More specifically, the ink is transferred onto the relief parts of the plate, i.e., into the halftone dots or solid relief, and not onto the non-relief parts. During printing, the ink on the relief parts is transferred to the printing medium. Grayscale images are typically created using halftoning, for example using a screening pattern, preferably an AM screening pattern. Grayscale means, in a plate printed with a particular color, the amount of that color that is reproduced. For example, a printing plate may contain different halftone dot areas to print in those areas with different densities. To increase the amount of ink transferred and increase the so-called ink density on the substrate, an additional very fine structure is applied to the surface of the printing dots, i.e., the relief areas. This fine surface structure is typically obtained by adding a fine high-resolution sampling pattern to the image file, which is then transferred to the corresponding mask used for exposure.

[0075] The image reproduced by a printing plate typically contains both solid image areas and various gray-tone areas, also called halftone areas. A solid area corresponds to a single relief in the printing plate that is completely covered by ink to produce maximum density on the printing material. A gray-tone or halftone area corresponds to an area with multiple printing dots spaced apart from each other, i.e. an area where the appearance of the printed image is intermediate density between pure white (no ink at all) and pure color (completely covered by ink). Gray areas are produced by the process of halftoning, which uses multiple relief elements per unit area to create the illusion of different densities of printing. These relief elements are commonly referred to in the printing industry as "halftone dots". Image presentation is achieved by varying the area coverage (dot intensity) from area to area. Dot intensity can be altered by changing the dot size (AM screening) and / or the dot density, i.e. the dot frequency (FM screening).

[0076] In a flexographic or letterpress plate, a halftone dot is a relief area with a surface on the top surface of the plate. The plate in the area surrounding the dot is etched to a depth that reaches the bottom. The height of the halftone dot is the distance from the surface of the dot (and the plate surface) to the bottom. The halftone relief is a relief that extends from the bottom to the top surface.

[0077] In the present method for imaging a mask layer, first a mask layer is provided. The provided mask layer is, for example, a blank mask layer without any imaged pixels. The mask layer may be disposed on a support layer and attached to a relief master before exposure to electromagnetic radiation for curing. The mask layer may be an integral part of the relief master or may correspond to the outer surface of the master being imaged.

[0078] Next, imaging data of a sequence of at least C1+C2 pixels is read out, the imaging data coming, for example, from an image file, where C1 and C2 are integers equal to or greater than 1.

[0079] According to one embodiment, C1 and C2 are integers equal to or greater than 2. In this embodiment, the C1 pixels of the first group are preferably selected such that at least two pixels of the first group are separated by at least one pixel that does not belong to the first group, and / or the C2 pixels of the second group are preferably selected such that at least two pixels of the second group are separated by at least one pixel that does not belong to the second group. The distance between two pixels in a group is, for example, about 30 microns. According to a preferred embodiment, all pixels in the first group are separated by at least one pixel that does not belong to the first group, and / or all pixels in the second group are separated by at least one pixel that does not belong to the second group.

[0080] According to some embodiments, C1=C2=C. Each sequence contains N*C pixels, where N is an integer equal to or greater than 2. N represents the number of groups in the following description. In the embodiment shown in FIG. 1, C1=C2=3 and N=2. This means that there are two groups of pixels, with three pixels per group. In the embodiment shown in FIG. 8, C1=C2=2 and N=3. This means that there are three groups of pixels, with two pixels per group.

[0081] At a first time point, a group L1 of a first imaging beam of C1 is used to substantially simultaneously image a first group of C1 pixels in a sequence of C1+C2 pixels according to the read-out imaging data.

[0082] At a second time point, a group L2 of the second imaging beams of C2 is used to substantially simultaneously image a second group of C2 pixels in the sequence of C1+C2 pixels according to the read-out imaging data.

[0083] According to some embodiments, imaging data for a first group of C1 pixels is read out and the first group of C1 pixels is imaged, after which imaging data for a second group of C2 pixels is read out and the second group of C2 pixels is imaged.

[0084] Alternatively, imaging data of the first and second groups of (C1+C2) pixels are read out before the first group of C1 pixels is imaged and / or the second group of C2 pixels is imaged.

[0085] According to some embodiments, a clock having a first frequency f1 is provided. The period between subsequent times corresponds to 1 / f1. According to these embodiments, when imaging data of at least (C1+C2) pixels is read out, first, as shown in FIG. 2, imaging data of C1 pixel is read out (and optionally, C1 pixel is imaged), for example, at time 1 / f1. Then, after an interval of 1 / f1, imaging data of C2 pixel is read out (and optionally, C2 pixel is imaged), for example, at time 2 / f1 in the example of FIG. 2.

[0086] According to some embodiments, the C pixels in the nth group, where n is an integer and 1≦n≦N, include the nth pixel, the (n+N)th pixel, the (n+2×N)th pixel, etc., of the sequence of N×C pixels. In the example of Figures 1 and 2, the first group of three pixels includes the first, third, and fifth pixels in the sequence of six pixels. The second group of three pixels includes the second, fourth, and sixth pixels in the sequence of six pixels.

[0087] According to some embodiments, such as the one shown in FIG. 1, the sequence corresponds to a single row in the imaging data. In these embodiments, after a group of pixels in a first row is imaged, the method proceeds to image a second row of pixels. Further, in the example of two groups of pixels with three pixels per group (N=2; C=3) as shown in FIG. 2, at one time, say 3 / f1, the first, third, and fifth pixels of the second row are imaged with the first group L1 of the imaging beam. At another later time, say 4 / f1, the second, fourth, and sixth pixels of the second row are imaged with the second group L2 of the imaging beam.

[0088] According to some other embodiments not shown in the figures, the sequences correspond to portions of different rows in the imaging data. According to a preferred implementation of this embodiment, the C pixels in the nth group include the nth pixel in the mth row, the (n+N)th pixel in the (m+1)th row, the (n+2*N)th pixel in the (m+2)th row, ..., where 1≦m≦N and m is an integer. Again, using the example of FIG. 1 where N=2 and C=3, the pixels in the first group include the first pixel in the first row, the third pixel in the second row, and the fifth pixel in the third row. The pixels in the second group include the second pixel in the first row, the fourth pixel in the second row, and the sixth pixel in the third row. Using the example of FIG. 8 where N=3 and C=2, the pixels in the first group include the first pixel in the first row and the fourth pixel in the second row, the pixels in the second group include the second pixel in the first row and the fifth pixel in the second row, and the pixels in the third group include the third pixel in the first row and the sixth pixel in the second row.

[0089] According to some optional embodiments, at one or more subsequent time points, a subsequent group L3 of imaging beams is used to image a subsequent group of pixels substantially simultaneously according to the read-out imaging data. The pixels of the subsequent group are different from the pixels of the first and second groups. In the embodiment shown in FIG. 8, at a subsequent time point, for example at time point 3 / f1, a third group L3 of imaging beams is used to image a third group of pixels substantially simultaneously.

[0090] According to some embodiments, the method includes acquiring a first set of imaging settings for a first group of C1 pixels and imaging the first group of C1 pixels substantially simultaneously according to the first set of imaging settings. The acquisition of the first set of imaging settings is performed, for example, between readout of imaging data of all groups of pixels and imaging of the first group of C1 pixels. According to some embodiments, the method includes acquiring a second set of imaging settings for a second group of C2 pixels and imaging the second group of C2 pixels substantially simultaneously according to the second set of imaging settings. The acquisition of the second set of imaging settings is performed, for example, between readout of imaging data of all groups of pixels and imaging of the second group of C2 pixels. Alternatively, the acquisition of the first set and the second set of imaging settings is performed before imaging of the first group of C1 pixels and before imaging of the second group of C2 pixels. According to some embodiments, the acquisition of the entire set of imaging settings is performed before imaging of any pixel or any group of pixels. According to some embodiments, the set of imaging settings for at least two groups of pixels is different. According to some embodiments, for each group of pixels, the set of imaging settings is different.

[0091] Optionally, the method includes obtaining a subsequent set of imaging settings for a subsequent group of pixels and substantially simultaneously imaging the subsequent group of pixels according to the subsequent set of imaging settings, for example performed between readout of imaging data for all groups of pixels and imaging the subsequent group of pixels.

[0092] According to some embodiments, obtaining the first set of imaging settings or the second set of imaging settings includes looking up the imaging settings in a lookup table based on a set of bit values ​​of the image data corresponding to the one group or the second group of pixels, respectively. Details of how to look up the imaging settings in the lookup table are described in more detail below.

[0093] According to some embodiments, the mask layer is moved in a movement direction M relative to the imaging beams L1, L2, L3, during which the first group of C1 pixels and the second group of C2 pixels, as well as subsequent groups of pixels, if present, are imaged. This cam means that the mask layer moves when the imaging beams L1, L2, L3 remain stationary. This can mean that the image beans L1, L2, L3 move at the same time that the mask layer remains stationary. This can also mean that both the mask layer and the imaging beams L1, L2, L3 move, one having a relative movement with respect to the other.

[0094] If the mask layer is moved in a movement direction M, there are three preferred embodiments. A first preferred embodiment is when the mask layer rotates on a drum. In this preferred embodiment, the movement direction M corresponds to the rotation direction of the drum, as shown in Fig. 1 and Fig. 8. A second preferred embodiment (not shown) is when the mask layer is moving on a flatbed table and / or the imaging beams L1, L2, L3 are moving along the flatbed table. The movement direction M in this preferred embodiment corresponds to the longitudinal direction of the flatbed table. The longitudinal direction of the flatbed table is the direction in which the flatbed table exhibits its largest dimension in the horizontal plane. A third possibility is to position the mask layer on the inside of a hollow drum, for example positioned on the inner surface of the drum, and to perform the exposure with a beam generator positioned in the center of the drum. According to one embodiment, when the mask layer is positioned inside the drum, it rotates with the drum while the source emitting the imaging beams L1, L2, L3 remains stationary in the drum, during which the first group of C1 pixels and the second group of C2 pixels, as well as subsequent groups of pixels, if present, are imaged. According to another embodiment, when the mask layer is positioned inside the drum, it remains stationary while the source emitting the imaging beams L1, L2, L3 rotates inside the drum, during which the first group of C1 pixels and the second group of C2 pixels, as well as subsequent groups of pixels, if present, are imaged. In this embodiment, the source may also move in a lateral direction perpendicular to the rotation direction of the drum. The lateral direction is, for example, the longitudinal direction of the drum. According to yet another embodiment, when the mask is positioned inside the drum, both the mask layer and the source emitting the imaging beams L1, L2, L3 are rotated, and the mask layer rotates relative to the imaging beams L1, L2, L3, while the first group of C1 pixels and the second group of C2 pixels, as well as subsequent groups of pixels, if present, are imaged. In this embodiment, the source may also move in a lateral direction perpendicular to the direction of rotation of the drum. The lateral direction is, for example, the longitudinal direction of the drum.

[0095] If the mask layer moves in a movement direction M relative to the imaging beams L1, L2, L3, in some embodiments the first and second groups of imaging beams L1, L2 and, if present, the subsequent group L3 of imaging beams are arranged next to each other and are aligned along a line when the groups of imaging beams L1, L2, L3 are observed perpendicular to the mask layer. Preferably, the line defines an angle with a transverse direction T perpendicular to the movement direction M. The angle is strictly greater than 0 and strictly less than 90°. The angle compensates for the movement of the mask layer between the first and second time points. Preferably, the compensation allows imaging of pixels aligned in the transverse direction T even if the mask layer moves between the movement when the first group of pixels is imaged and the movement when the second group of pixels is imaged.

[0096] According to some embodiments, the method includes moving the imaging beams L1, L2, L3 in a lateral direction T perpendicular to the movement direction M relative to the mask layer. In these embodiments, the imaging beams L1, L2, L3 move in the lateral direction T relative to the drum over at least (C1+C2) pixels. When the drum completes one rotation, the imaging beams L1, L2, L3 move in the lateral direction T by, for example, C1+C2 pixels. According to some embodiments, the movement in the lateral direction T perpendicular to the movement direction M is substantially continuous. This is particularly advantageous if the mask layer is rotating on the drum. According to some embodiments, the movement in the lateral direction T perpendicular to the movement direction M is stepwise. This is particularly advantageous if the mask layer is positioned on a flatbed table.

[0097] According to some embodiments, the method includes moving the imaging beams L1, L2, L3 relative to the mask layer in a lateral direction T perpendicular to the direction of movement M, such that the imaging beams L1, L2, L3 move relative to the mask layer by at least (C1+C2) pixels in the lateral direction T. The imaging beams L1, L2, L3 move by C1+C2 pixels in the lateral direction T, for example, as the mask layer moves across the longitudinal length of the flatbed table.

[0098] 2, the method further includes repeating the reading out of the imaging data, using the first group L1 of imaging beams of C1 for imaging at a first time point, using the second group L2 of imaging beams of C2 for imaging at a second time point, and optionally using a subsequent group L3 of imaging beams for imaging at one or more subsequent time points for a next sequence of at least (C1+C2) pixels. According to some embodiments, the period between reading out the imaging data of the first sequence of N*C pixels and reading out the imaging data of the subsequent sequence of N*C pixels corresponds to N / f1.

[0099] Lookup Table According to some embodiments of the present disclosure, a lookup table is used to obtain imaging settings for at least the beams L1, L2, and L3 based on a bit sequence of the imaging data corresponding to a plurality of pixels. The lookup table includes, for example, a plurality of imaging settings according to the bit sequence.

[0100] An example of a lookup table according to some embodiments of the present disclosure is shown in FIG.

[0101] According to some embodiments, such as those shown in Figure 3, the set of bit values ​​includes, for each pixel, either a "1" if the pixel is an imaging pixel or a "0" if the pixel is a non-imaging pixel. Alternatively, the set of bit values ​​includes more than one bit value for each pixel. The bit value is "2" if the pixel is an imaging pixel in a solid area, "1" if the pixel is an imaging pixel in a halftone area, or "0" if the pixel is a non-imaging pixel.

[0102] According to some embodiments, the first set of imaging settings and the second set of imaging settings include an imaging setting of C1 for the first imaging beam L1 of C1 and an imaging setting of C2 for the second imaging beam L2 of C2, respectively. In this way, each imaging beam L1, L2, L3 has its own imaging setting for the imaging beam L1, L2, L3. The imaging setting of one beam can be independent of the imaging settings of the other beams in the group. In other words, the imaging setting includes multiple independent values ​​for the multiple imaging beams L1, L2, L3. Alternatively, the imaging setting of one beam can be a function of the imaging settings of the other beams in the group. According to some embodiments, the imaging setting is modified before the modified imaging setting is used by the beam to image the pixel. The modified imaging setting includes, for example, a modified beam location and / or a modified beam intensity of at least one beam.

[0103] According to some embodiments, each imaging setting specifies values ​​that represent the size and / or shape and / or position of the imaged spot corresponding to the imaging pixel. Preferably, the imaging settings are the following parameters: - an intensity value used to generate an imaged feature corresponding to an imaging pixel, e.g., an intensity value for controlling a beam used for imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for imaging; - beam diameter values ​​and / or beam shape values ​​for controlling the beam used for imaging, - the number of passes used for imaging, - an indication of which exposure head of a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to a pixel or group of pixels for imaging; Define one or more of the following:

[0104] According to some embodiments, the size (from controlling the intensity of the beam) and / or the shape and / or the position of the beam are controlled by controlling the amplitude and / or the frequency and / or the phase of an input wave that is transmitted to the beam to control the beam. Acousto-optical systems can control the parameters of a beam by controlling the amplitude and / or the frequency and / or the phase of an input wave of the beam. Electro-optical systems can also control the parameters of a beam by controlling the amplitude and / or the frequency and / or the phase.

[0105] After the imaging settings are obtained from the look-up table, the method uses the multiple imaging beams L1, L2, L3 to substantially simultaneously image multiple pixels according to the obtained imaging settings.

[0106] According to some embodiments, the look-up table is determined before the image file is received.

[0107] According to some embodiments, the sequence of bit values ​​includes at least two bit values ​​per pixel. The method includes acquiring an imaging setting based on the sequence of bit values ​​including at least two bit values. The acquisition of the imaging setting can be based on a lookup table as described above or can be based on no lookup table. The method then uses multiple imaging beams L1, L2, L3 to image multiple pixels substantially simultaneously according to the acquired imaging setting.

[0108] According to some embodiments, a method includes detecting at least one solid area and at least one halftone area in an imaging file, where pixels in the solid area receive, for example, a value of "2", pixels in the halftone area receive, for example, a value of "1", and non-imaging pixels receive, for example, a value of "0".

[0109] According to some embodiments, the method includes converting at least two bit values ​​to several corresponding one bit values ​​before obtaining the imaging settings based on the one bit value. According to some embodiments, the method includes converting an original string of C1 values ​​expressed in ternary notation to a binary string of 2*C1 binary values. The binary value of the first C1 of the binary string is, for example, "1" if the pixel corresponds to one in a solid area (i.e., has an original value of "2"). The binary value of the second C1 of the binary string is, for example, "1" if the pixel corresponds to an imaging pixel (i.e., has an original value of "1" or "2"). The same conversion may be applied to the original string of C2 values ​​and any potential subsequent string(s) of bit values.

[0110] 4 through 7 show four examples of converting a set of two bit values ​​into instructions for four beams, including converting a sequence of two bit values ​​into a sequence of one bit values. In FIG. 4, the set of two bit values ​​is 2212. This set of two bit values ​​is first converted into two strings of one bit values, 1101 and 1111, according to the method described above. The second string contains only "1's", so all four beams are on. In the first string, the first, second, and fourth values ​​are "1's", so the first, second, and fourth beams image pixels in at least one solid area. The third value in the first string is "0", so the third beam images pixels in a halftone area with reduced beam intensity. This information is used to command the beams, as seen in FIG. 4.

[0111] In FIG. 5, the set of two bit values ​​is 2221. This set of two bit values ​​is first converted to two strings of one bit values, 1110 and 1111, according to the method described above. Again, the second string contains only "1"s, and therefore all four beams are on. The first, second, and third values ​​in the first string are "1"s, and therefore these three values ​​correspond to solid areas. Thus, the first, second, and third beams will image pixels in at least one solid area. The fourth value in the first string is "0", and therefore the fourth beam will image pixels in a halftone area with reduced beam intensity. This information is used to command the beams, as seen in FIG. 5.

[0112] In FIG. 6, the set of two bit values ​​is 1112. This set of two bit values ​​is first converted to two strings of one-bit values, 0001 and 1111, according to the method described above. Again, the second string contains only "1's", so all four beams are on. The first, second, and third values ​​in the first string are "0's", so the first, second, and third beams image pixels in at least the halftone areas with reduced beam intensity. The fourth value in the first string is 1, so the fourth beam images pixels in the solid areas. This information is used to command the beams, as seen in FIG. 6.

[0113] In FIG. 7, the set of two bit values ​​is 1100. This string of two bit values ​​is first converted to two strings of one bit values, 0000 and 1100, according to the method described above. The third and fourth values ​​in the second string are "0", so the third and fourth beams are off and do not image any pixels. The first and second values ​​in the second string are "1", so the first and second beams are on. The first and second values ​​in the first string are "0", so the first and second beams image pixels at least in the halftone region with reduced beam intensity. This information is used to command the beams, as seen in FIG. 7.

[0114] FIG. 9 shows a system from a relief master to a relief structure. The system comprises a control module 100, an imager 110, an exposure means 120 and a development means 130. After the mask layer on the master is imaged by the imager 110 with the modified image file and / or imaging instructions generated by the control module 100, the master is exposed to electromagnetic radiation in the exposure means 120 through the imaging mask layer, resulting in the hardening of a portion of the photosensitive layer. The electromagnetic radiation may have a wavelength in the range of 200-2000 nm, preferably ultraviolet (UV) radiation with a wavelength in the range of 200-450 nm. The imager 110 used for the imaging step is configured to generate a beam of the aforementioned electromagnetic radiation, typically a laser beam, capable of modifying the transparency of the mask layer. The modification of the transparency can be achieved by ablation, bleaching, color modification, refractive index modification or a combination thereof. Preferably, ablation or bleaching is employed. Preferably, the wavelength of the beam of electromagnetic radiation is in the range of 700 nm to 12,000 nm.

[0115] The mask layer may be a separate layer that is applied to the relief master, typically after removal of a protective layer that may optionally be present, or it may be an integral layer of the master, in contact with the relief layer or one of the optional layers above the relief layer and covered by a protective layer that may be present.

[0116] The mask layer can also be a commercially available negative that can be produced, for example, by a photographic method based on silver halide chemistry.The mask layer can be a composite layer material in which a transparent layer is produced in an otherwise opaque layer by image-based exposure, as described, for example, in EP-A-3139210, EP-A-1735664, EP-A-2987030, EP-A-2313270.This can be carried out by ablation of an opaque layer on a transparent carrier layer, as described, for example, in U.S. Pat. No. 6,916,596, EP-A-816920, or by selectively applying an opaque layer to a transparent carrier layer, as described, for example, in EP-A-992846, or can be written directly on the relief-forming layer, for example, by printing with an opaque ink by inkjet, as described, for example, in EP-A-195645.

[0117] Preferably, the mask layer is an integral layer of the relief master and is positioned in direct contact with the relief-forming layer or with a functional layer arranged on the relief-forming layer, which is preferably a barrier layer. Furthermore, the integral mask layer can be imaged by ablation and can be further removed by a solvent or by heating and adsorption / absorption. For example, this layer may be heated and liquefied by selective irradiation with high-energy electromagnetic radiation, which produces an image-based structured mask used to transfer the structure to the relief master. For this purpose, this layer may be opaque in the UV range and absorb radiation in the visible IR range, thereby resulting in heating of the layer and ablation of the layer. After ablation, the mask layer also typically exhibits a lower relief height, for example a relief in the range of 0.1 to 5 μm.

[0118] In an exemplary embodiment, the optical density of the mask layer in the UV range of 330-420 nm and / or in the visible IR range of 340-660 nm is in the range of 1-5, preferably in the range of 1.5-4, particularly preferably in the range of 2-4.

[0119] The thickness of the laser-ablatable mask layer is generally 0.1 to 5 μm. The thickness is preferably 0.3 to 4 μm, and more preferably 1 to 3 μm. The laser sensitivity of the mask layer (1 cm 2 The energy required to ablate a layer of the laser (measured as the energy required to ablate the layer) ranges from 0.1 to 10 mJ / cm 2 , preferably 0.3 to 5 mJ / cm 2 , and particularly preferably 0.5 to 5 mJ / cm 2 It could be.

[0120] Examples of solidifiable materials that may be used in the photosensitive layer according to some embodiments of the present invention are photosensitive compositions that solidify or harden by chemical reactions that result in polymerization and / or crosslinking. Such reactions may be radical, cationic, or anionic polymerization and crosslinking. Other means for crosslinking are condensation or addition reactions, for example, the formation of esters, ethers, urethanes, or amides. Such compositions may include initiators and / or catalysts that are triggered by electromagnetic radiation. Such initiators or catalysts may be photoinitiator systems with one or more components that form radicals, acids, or bases, thereby initiating or catalyzing the reactions that result in polymerization or crosslinking. The required functional groups may be attached to low molecular weight monomers, oligomers, or polymers. In addition, the compositions may include additional components such as binders, fillers, colorants, stabilizers, surfactants, inhibitors, modifiers, and other additives, which may or may not have functional groups used in the solidification reaction. Depending on the components used, flexible and / or rigid materials can be obtained after solidification and post-processing are completed. The radical reactions may be radical polymerization, radical crosslinking reactions, or a combination thereof. Preferably, the photosensitive layer is rendered insoluble, solid, or infusible by the radical reaction.

[0121] The electromagnetic radiation changes the properties of the exposed portions of the photosensitive layer such that in a subsequent development step the unexposed portions of the photosensitive layer are removed by development means 130 to form a relief structure, such as a printing plate or sleeve.

[0122] Preferably, removal of the soluble or liquefiable material is accomplished by treatment with a liquid (solvent, water, or aqueous solution) or by thermal development, which results in the liquefied or softened material being removed.

[0123] Treatment with a liquid may be carried out by spraying the liquid onto the master, brushing or scrubbing the master in the presence of the liquid. The nature of the liquid used depends on the nature of the master employed. If the layer to be removed is soluble, emulsifiable or dispersible in water or an aqueous solution, water or an aqueous solution may be used. If the layer is soluble, emulsifiable or dispersible in an organic solvent or mixture, an organic solvent or mixture may be used. Preferably, a liquid comprising, for example, a mixture of naphthenic or aromatic petroleum fractions with an alcohol, such as benzyl alcohol, cyclohexanol or an aliphatic alcohol having 5 to 10 carbon atoms, and further optionally further components, such as, for example, alicyclic hydrocarbons, terpenoid hydrocarbons, substituted benzenes such as diisopropylbenzene, esters having 5 to 12 carbon atoms, or glycol ethers.

[0124] For thermal development, a thermal development means may be used in which the relief master is fixed on a rotating drum. The thermal development means further comprises an assembly for heating the at least one additional layer and a further assembly for contacting the outer surface of the heated at least one additional layer with an absorbent material for absorbing the material in the molten state. The assembly for heating may comprise a heatable underlay for the relief master and / or an IR lamp arranged above the at least one additional layer. The absorbent material may be pressed against the surface of the at least one additional layer, for example, by an optionally heatable roll. The absorbent material may be moved continuously across the surface of the flexible plate while the drum rotates, repeatedly removing the material of the at least one additional layer. In this way, the melted material is removed, but the non-melted areas remain, forming the relief.

[0125] The relief master may be a master of an element selected from the group including flexographic printing plates, relief printing plates, letterpress plates, intaglio plates, (flexible) printed circuit boards, electronic elements, microfluidic elements, microreactors, electrophoretic cells, photonic crystals, and optical elements such as Fresnel lenses.

[0126] Optionally, the imaging system may further comprise an exposure unit, a washer, a dryer, a photofinisher, or any other post-exposure unit, a storage unit, a cutting unit, an attachment unit, or any combination thereof, to generate the relief structure as described above.

[0127] The relief structure may be further processed and may ultimately be used as a printing plate. Optionally, the system may further comprise an optical finisher or any other post-exposure unit. Optionally, a controller may be provided for controlling various units of the imaging system. Optionally, one or more pre-processing modules may be provided upstream of the control module 100, such as a raster image processing (RIP) module that converts an image file, such as a pdf file, into a raster image process file.

[0128] While the principles of the present invention have been described above with reference to specific embodiments, it should be understood that this description is made by way of example only and does not limit the scope of protection determined by the appended claims.

Claims

1. 1. A method for imaging a mask layer, comprising: providing the mask layer; providing a plurality of at least (C1+C2) imaging beams arranged adjacent to each other, the plurality of imaging beams including a first group (L1) of C1 imaging beams and a second group (L2) of C2 imaging beams; reading out imaging data of a sequence of at least (C1+C2) pixels, where C1 and C2 are integers equal to or greater than 1; using a first group of C1 imaging beams (L1) for substantially simultaneously imaging a first group of C1 pixels of the sequence according to the read-out imaging data at a first time point; using a second group of C2 imaging beams (L2) for substantially simultaneously imaging a second group of C2 pixels of the sequence according to the read-out imaging data at a second time point; Optionally, at one or more subsequent time points, using a subsequent group of imaging beams (L3) for substantially simultaneously imaging a subsequent group of pixels according to the read-out imaging data, wherein the pixels of the subsequent group are different from the pixels of the first group and the second group; repeating the steps of reading out the imaging data, using a first group (L1) of imaging beams of C1 for imaging at the first time point, using a second group (L2) of imaging beams of C2 for imaging at the second time point, and optionally using a subsequent group (L3) of the imaging beams for imaging at the one or more subsequent time points for a next sequence of at least (C1+C2) pixels; A method comprising:

2. 2. The method of claim 1 , wherein C1 and C2 are integers equal to or greater than 2, and the C1 pixels of the first group are selected such that at least two pixels of the first group are separated by at least one pixel that does not belong to the first group, and the C2 pixels of the second group are selected such that at least two pixels of the second group are separated by at least one pixel that does not belong to the second group.

3. 3. The method of claim 2, wherein C1 = C2 = C and each sequence contains N*C pixels, where N is an integer greater than or equal to 2.

4. 4. The method according to claim 1, further comprising the step of providing a clock having a first frequency f1, wherein a period between subsequent time points corresponds to 1 / f1, and wherein the step of reading out the imaging data of the at least (C1+C2) pixels comprises the steps of reading out imaging data of the C1 pixels and then, after an interval of 1 / f1, reading out imaging data of the C2 pixels.

5. 5. The method according to claim 3, wherein the period between the readout of the imaging data of a first sequence and the readout of the imaging data of a subsequent sequence corresponds to N / f1.

6. 6. The method of claim 3 and any one of claims 1 to 5, wherein the C pixels in the nth group, where n is an integer and 1≦n≦N, include the nth pixel, the (n+N)th pixel, the (n+2*N)th pixel, etc. of the sequence of N*C pixels.

7. A method according to claim 3 and any one of claims 1 to 6, wherein the sequence corresponds to a single row in the imaging data.

8. A method according to claim 3 and any one of claims 1 to 6, wherein the sequence corresponds to portions of different rows in the imaging data, preferably the C pixels in the nth group include the nth pixel in the mth row, the (n+N)th pixel in the (m+1)th row, the (n+2*N)th pixel in the (m+2)th row, ..., where 1≦m≦N and m is an integer.

9. 9. The method of claim 1, further comprising the steps of: obtaining a first set of imaging settings for a first group of C1 pixels; imaging the first group of C1 pixels substantially simultaneously according to the first set of imaging settings; obtaining a second set of imaging settings for a second group of C2 pixels; and imaging the second group of C2 pixels substantially simultaneously according to the second set of imaging settings, wherein for each group of pixels the set of imaging settings is different.

10. obtaining the first set of imaging settings or the second set of imaging settings includes searching an imaging setting in a lookup table based on a set of bit values ​​of image data corresponding to the pixels of the first group or the second group, respectively; Preferably, the set of bit values ​​includes, for each pixel, either a "1" if the pixel is an imaging pixel, or a "0" if the pixel is a non-imaging pixel.

10. The method of claim 9.

11. The method of claim 10 , wherein the set of bit values ​​includes two or more bit values ​​for each pixel.

12. 12. The method of claim 10 or 11, wherein the first set of imaging settings and the second set of imaging settings respectively include an imaging setting of C1 for a first imaging beam (L1) of C1 and an imaging setting of C2 for a second imaging beam (L2) of C2.

13. Each set of imaging settings specifies values ​​that represent a size and / or shape and / or position of an imaged spot corresponding to an imaging pixel, preferably said first set of imaging settings and said second set of imaging settings are the following parameters: an intensity value used to generate an imaged feature corresponding to an imaging pixel, e.g., an intensity value for controlling a beam used for said imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for said imaging; beam diameter and / or beam shape values ​​for controlling the beam used for said imaging; the number of passes used for said imaging; an indication of which exposure head among a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to said pixel or group of pixels for imaging; The method according to any one of claims 10 to 12, further comprising defining any one or more of:

14. 14. The method according to claim 1, wherein all the pixels in the first group are separated by at least one pixel that does not belong to the first group, and all the pixels in the second group are separated by at least one pixel that does not belong to the second group.

15. 15. The method according to any one of claims 1 to 14, wherein the mask layer is moved in a movement direction (M) relative to the imaging beam (L1, L2, L3) while a first group of C1 pixels and a second group of C2 pixels, and subsequent groups of pixels, if present, are imaged.

16. 16. The method of claim 15, wherein the mask layer is rotating on a drum while the first group of C1 pixels and the second group of C2 pixels, and subsequent groups of pixels, if present, are imaged, and the direction of movement (M) corresponds to a direction of rotation of the drum.

17. 16. The method of claim 15, wherein the mask layer is positioned on an inner surface of a drum, the mask layer is rotated relative to the imaging beam (L1, L2, L3) while a first group of C1 pixels and a second group of C2 pixels, and subsequent groups of pixels, if present, are imaged, and the movement direction (M) corresponds to a rotation direction of the mask layer or the imaging beam (L1, L2, L3).

18. 16. The method according to claim 15, wherein the mask layer is moving on a flat bed table and / or the imaging beam (L1, L2, L3) is moving along the flat bed table while the first group of C1 pixels and the second group of C2 pixels, and if present, subsequent groups of pixels, are imaged, and the direction of movement (M) corresponds to the longitudinal direction of the flat bed table.

19. 19. The method according to any one of claims 15 to 18, wherein the first group of imaging beams and the second group of imaging beams (L1, L2), and, if present, the subsequent group of imaging beams (L3), are arranged next to each other and are aligned along a line when the groups of imaging beams (L1, L2, L3) are observed perpendicular to the mask layer, the line defining an angle with a transverse direction (T) perpendicular to the direction of movement (M), the angle compensating for the movement of the mask layer between the first and second time points.

20. A method according to claim 15 and any one of claims 1 to 14 or 16 to 19, further comprising a step of moving the imaging beams (L1, L2, L3) relative to the mask layer in a lateral direction (T) perpendicular to the direction of movement such that the imaging beams (L1, L2, L3) move relative to the mask layer over at least (C1+C2) pixels in the lateral direction (T).

21. 21. The method of claim 20, wherein the step of moving in the lateral direction (T) perpendicular to the direction of movement (M) is substantially continuous.

22. 1. A method for imaging a mask layer, comprising: providing the mask layer; providing a look-up table having a plurality of imaging settings according to a bit sequence; reading out imaging data for a plurality of pixels; retrieving imaging settings from the look-up table based on a bit sequence of the imaging data corresponding to the plurality of pixels, each imaging setting specifying a value representing a size and / or shape of an imaged spot corresponding to an imaging pixel; using a plurality of imaging beams (L1, L2, L3) for imaging the plurality of pixels substantially simultaneously according to the acquired imaging settings; A method comprising:

23. 23. The method of claim 22, wherein the set of bit values ​​includes, for each pixel, a "1" if the pixel is an imaging pixel and a "0" if the pixel is a non-imaging pixel.

24. 24. A method according to claim 22 or 23, wherein the set of bit values ​​comprises at least two bit values ​​for each pixel.

25. The method according to any one of claims 22 to 24, wherein the imaging settings comprise a plurality of distinct and independent values ​​for the plurality of imaging beams (L1, L2, L3).

26. The imaging settings are the following parameters: an intensity value used to generate an imaged feature corresponding to an imaging pixel, e.g., an intensity value for controlling a beam used for said imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for said imaging; beam diameter and / or beam shape values ​​for controlling the beam used for said imaging; the number of passes used for said imaging; an indication of which exposure head among a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to said pixel or group of pixels for imaging; The method according to any one of claims 22 to 25, further comprising defining any one or more of:

27. The step of reading out the imaging data comprises reading out imaging data of a sequence of at least (C1+C2) pixels, where C1 and C2 are integers equal to or greater than 1; the step of obtaining the imaging settings comprises obtaining a first imaging setting based on a plurality of first bit values ​​corresponding to C1 pixels of the sequence, and a second imaging setting based on a plurality of second bit values ​​corresponding to C2 pixels of the sequence; and the step of using the plurality of imaging beams (L1, L2, L3) for imaging comprises: using a first group of C1 imaging beams (L1) for substantially simultaneously imaging a first group of C1 pixels of the sequence according to the first imaging setup at a first time point; using a second group of C2 imaging beams (L2) for substantially simultaneously imaging a second group of C2 pixels of the sequence according to the second imaging setup at a second time point; Optionally, at one or more subsequent time points, using a subsequent group of imaging beams (L3) for substantially simultaneously imaging a subsequent group of pixels according to the read-out imaging data, the pixels of the subsequent group being different from the pixels of the first group and the second group; Including, the method further comprising repeating the steps of reading out the imaging data, obtaining the imaging settings from the look-up table, and using the multiple imaging beams (L1, L2, L3) for imaging a next sequence of at least (C1+C2) pixels.

27. The method according to any one of claims 22 to 26.

28. 28. The method of claim 27, wherein C1 and C2 are integers equal to or greater than two, and the C1 pixels of the first group are selected such that at least two pixels of the first group are separated by at least one pixel that does not belong to the first group, and the C2 pixels of the second group are selected such that at least two pixels of the second group are separated by at least one pixel that does not belong to the second group.

29. 29. A method according to claim 27 or 28, wherein C1 = C2 = C and each sequence contains N*C pixels, where N is an integer greater than or equal to 2.

30. 30. The method of claim 29, wherein the C pixels in the nth group, where n is an integer and 1≦n≦N, include the nth pixel, the (n+N)th pixel, etc., of the sequence of N*C pixels.

31. 31. A method according to claim 29 or 30, wherein the sequence corresponds to a single row in the imaging data or the sequence corresponds to portions of different rows in the imaging data, preferably the C pixels in the nth group include the nth pixel in the mth row, the (n+N)th pixel in the (m+1)th row, the (n+2*N)th pixel in the (m+2)th row, ..., where 1 < m < N and m is an integer.

32. 1. A method for imaging a mask layer, comprising: providing the mask layer; reading out imaging data for a plurality of pixels; obtaining an imaging setting based on a sequence of bit values, the sequence including at least two bit values ​​for each pixel of the plurality of pixels; using a plurality of imaging beams (L1, L2, L3) for imaging the plurality of pixels substantially simultaneously according to the acquired imaging settings; A method comprising:

33. 33. The method of claim 32, wherein the imaging settings include a plurality of separate and independent values ​​for the plurality of imaging beams (L1, L2, L3).

34. Each imaging setting specifies values ​​representative of the size and / or shape and / or position of the imaged spot corresponding to an imaging pixel, preferably said imaging settings being the following parameters: an intensity value used to generate an imaged feature corresponding to an imaging pixel, e.g., an intensity value for controlling a beam used for said imaging; A time interval used to generate an imaged feature corresponding to an imaging pixel, e.g., an on-time value for controlling a beam used for said imaging; beam diameter and / or beam shape values ​​for controlling the beam used for said imaging; the number of passes used for said imaging; an indication of which exposure head among a plurality of exposure heads should be used to generate an imaged feature or group of imaged features corresponding to said pixel or group of pixels for imaging; 34. The method of claim 32 or 33, further comprising defining any one or more of:

35. 35. The method according to any one of claims 32 to 34, wherein the mask layer is provided on the photopolymerizable layer of a relief master, and after the imaging, the photopolymerizable layer of the relief master is exposed through the mask layer and the relief master is developed to obtain a relief structure.

36. A relief structure obtained by the method of claim 35.

37. A computer program or computer program product comprising computer executable instructions which, when said program is run on a computer, control a method according to any one of claims 1 to 35.

38. A digital data storage medium encoding a machine-executable program of instructions for controlling any one of said steps of the method of any one of claims 1 to 35.

39. reading out imaging data of a sequence of at least (C1+C2) pixels, C1 and C2 being integers greater than or equal to 1; Controlling a plurality of at least (C1+C2) imaging beams arranged adjacent to each other, the plurality of imaging beams including a first group (L1) of imaging beams of C1 and a second group (L2) of imaging beams of C2; controlling, at a first time point, a first group of C1 imaging beams (L1) to image a first group of C1 pixels of the sequence substantially simultaneously according to the read-out imaging data; controlling, at a second time point, a second group of C2 imaging beams (L2) to image a second group of C2 pixels of the sequence substantially simultaneously according to the read-out imaging data; Optionally, at one or more subsequent time points, controlling a subsequent group of imaging beams (L3) to image a subsequent group of pixels substantially simultaneously according to the read-out imaging data, wherein the pixels of the subsequent group are different from the pixels of the first group and the second group; repeating the reading out of the imaging data, the controlling a first group (L1) of the imaging beams of C1 for imaging at the first time point, the controlling a second group (L2) of the imaging beams of C2 for imaging at the second time point, and optionally the controlling a subsequent group (L3) of the imaging beams for imaging at the one or more subsequent time points for a next sequence of the at least (C1+C2) pixels. A control module configured to:

40. reading out imaging data for a plurality of pixels; obtaining imaging settings from a lookup table based on a bit sequence of the imaging data corresponding to the plurality of pixels, the lookup table having a plurality of imaging settings according to the bit sequence, each imaging setting specifying a value representing a size and / or shape of an imaged spot corresponding to an imaging pixel; controlling a plurality of imaging beams (L1, L2, L3) to image the plurality of pixels substantially simultaneously according to the acquired imaging settings; A control module configured to:

41. reading out imaging data for a plurality of pixels; obtaining an imaging setting based on a sequence of bit values ​​including at least two bit values ​​for each pixel of the plurality of pixels; controlling a plurality of imaging beams (L1, L2, L3) to image the plurality of pixels substantially simultaneously according to the acquired imaging settings; A control module configured to:

42. an imager configured to image the mask layer; A digital data storage medium according to claim 38 and / or a control module according to any one of claims 39 to 41 for controlling the imager. A system for processing a relief master comprising:

43. 43. The system of claim 42, comprising any one or more of the following: at least one transport system configured to transport the relief master; a storage device; an exposure means configured to expose the relief master through the imaged mask layer; a development means configured to remove at least a portion of unexposed material from the relief master; a drying system; a post-exposure apparatus; a cutting apparatus; a mounting station; and a heater.

44. A mask layer obtained by the method according to any one of the preceding claims.

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