Method, control module, and system for imaging a mask layer

Abstract

A method for imaging a mask layer, comprising the steps of: providing a mask layer; receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1; generating a modified image file based on the image file, the modified image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2; imaging the mask layer based on the modified image file such that the imaged spots have a maximum dimension smaller than (√2*P2), preferably smaller than P2.

Description

Technical Field

[0001] The field of the present invention relates to methods, control modules, and computer programs for imaging a mask layer and for controlling the imaging of a mask layer, in particular of a mask layer of a printing plate original. The field of the present invention further relates to a system for processing a relief original, in particular a printing plate original, more specifically a flexographic printing plate original or a letterpress printing plate original.

Background Art

[0002] Flexographic printing or letterpress printing is a technique commonly used for mass printing. A flexographic printing plate or a letterpress printing plate is a relief plate having image elements protruding above non-image elements for generating an image on a recording medium such as paper, cardboard, film, foil, laminate, etc. Also, a cylindrical printing plate or sleeve may be used.

[0003] There are various methods for producing a flexographic printing plate original or a letterpress printing plate original. According to conventional methods, a flexographic printing plate original or a letterpress printing plate original is produced from a multi-layer substrate comprising a backing layer and one or more photocurable layers. These photocurable layers are imaged by exposure to electromagnetic radiation through a mask layer containing image information or by direct and selective exposure to light in order to obtain a relief plate.

[0004] In flexographic or letterpress printing, ink is transferred from the plate to the printing medium. More specifically, the ink is transferred onto the relief portions of the plate rather than onto the non-relief portions. During printing, the ink on the relief portions is transferred to the printing medium. Grayscale images are typically created using halftoning, for example using a screening pattern. Grayscale refers to the amount of that color that is reproduced for a plate printed in a particular color. For example, a printing plate can include different halftone dot areas and be printed at different densities in those areas. To increase the amount of ink transferred and thus increase the so-called ink density on the substrate, additional very fine structures are applied to the surface of the printing area, i.e., the relief area. This surface screening is typically obtained by adding the fine structures to a raster image file and then transferring it to the corresponding mask used for exposure.

[0005] International Publication No. 2021110831 in the name of the applicant describes an example of an existing method for producing a relief version in FIGS. 1A to 1E. FIG. 1A shows the content of a raster image file having an image file resolution corresponding to a pixel size p (corresponding to the pitch), for example 6.35 micrometers. The image file resolution can be, for example, 4000 dpi (= 25400 * 1 / p (micrometers)). Next, the raster image file is manipulated using the surface screen pattern shown in FIG. 1B. The surface screen pattern is applied within the image area 1, resulting in the modified raster image file shown in FIG. 1C. As shown in FIG. 1C, the resulting image area 1’ contains fewer printed pixels 4’, and the printed pixels 4’ are positioned at a distance d from each other. Based on the modified raster image file of FIG. 1C, a mask is prepared. More specifically, for each printed pixel 4’, a hole or transparent region 5 is arranged within the mask. This may be done using a beam of electromagnetic radiation. As shown in FIG. 1D, such a beam will generate a hole 2, here a round hole 2, larger than the size of the pixel 4’. The resulting image on the mask is shown in FIG. 1E. Thus, according to the method shown in FIGS. 1A to 1E, surface screening is calculated by modifying the original raster image file, such as a tiff file, using software, typically raster image processing techniques, and typically by operation, a file having a larger size is generated.International Publication No. 2021110831 further discloses an improved method for processing a raster image file, the method comprising receiving a raster image file comprising image data for a plurality of pixels, analyzing the image data of the raster image file, and based on the analyzed image data, determining control data and optionally at least one new raster image file, wherein the control data is data for controlling the settings of an imaging device to change the physical properties of the generated and imaged features corresponding to one or more of the plurality of pixels, a determining step, using the control data, outputting the raster image file and / or the new raster image file to an imaging device for imaging a relief master. In this way, the image can be improved. For example, imaging may be controlled in different ways depending on whether the image data includes text and / or photos and / or barcodes and / or large continuous areas, etc. SUMMARY OF THE INVENTION

[0006] An object of embodiments of the present invention is to provide a method, a control module, and a computer program that can improve image quality in a more robust and simple way, especially when the image includes one or more solid areas.

[0007] According to a first aspect, a method for imaging a mask layer is provided. The method includes providing a mask layer, receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1, generating, based on the image file, a modified image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2, and imaging the mask layer based on the modified image file such that the imaged spots have a maximum dimension smaller than (√2*P2), preferably smaller than P2.

[0008] Embodiments of the present invention are based on the innovative insight that a fine surface structure can be obtained in a simple manner without the need for complex manipulation of the image file by first reducing the resolution of the image file and then selecting appropriate imaging settings such that the imaged spots do not fully overlap. This results in good image quality, especially when the image file includes one or more solid areas. In practice, by using a suitable low resolution in the solid areas, an appropriate surface structure can be obtained on the corresponding solid printing relief of the printing plate, and the ink on the solid printing relief will be more evenly distributed. Thus, trailing edge voids can be significantly reduced. In practice, channels will be created in the upper surface of the solid relief such that the resulting printing relief does not contact the substrate over an overly large area during printing.

[0009] According to a second aspect, a method for imaging a mask layer is provided. The method includes providing a mask layer, receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1, generating, based on the image file, signals corresponding to low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2, and imaging the mask layer such that the imaged spots have a maximum dimension smaller than (√2*P2), preferably smaller than P2.

[0010] The second aspect is similar to the first aspect, except that here the resolution reduction is performed in hardware without necessarily creating a modified image file. Thus, according to the second aspect, the image file, typically a raster image file, can be sent to a control module for controlling imaging without further processing / operating on the image data within the image file, and the resolution reduction can be performed "on the fly" in hardware.

[0011] Note that the pitch corresponds to the distance between the centers of adjacent pixels in a row, and this distance is typically equal to the pixel size. A first pitch P1 corresponds to the first resolution R1, and a second pitch P2 corresponds to the second lower resolution.

[0012] Preferably, the second resolution R2 and the imaging settings used for imaging are selected such that after exposing a relief original through the imaged mask layer and developing the exposed relief original, a surface structure of hills surrounded by valleys is generated on a printed relief corresponding to the solid areas.

[0013] Preferably, imaging is performed such that the maximum dimension of the imaged spot is less than 1 / 3*P1 + 2 / 3*P2, preferably less than (P1 + P2) / 2, or even more preferably less than P1, and / or preferably greater than P1 / 2. In such embodiments, the image spots will not overlap and an appropriate and fine surface structure for printing solid areas can be generated.

[0014] Preferably, the second resolution R2 is less than 2 / 3 of the first resolution R1, preferably less than or equal to half of the first resolution R1, and / or preferably less than or equal to one third of the first resolution R1. The inventors have found that such a reduction in resolution provides a good compromise between accuracy and ink density.

[0015] In an exemplary embodiment, generating includes determining that a low-resolution pixel of the modified image file is a low-resolution imaging pixel if the low-resolution pixel contains more or an equal number of imaging pixels than non-imaging pixels within the image file, and determining that the low-resolution pixel is a low-resolution non-imaging pixel otherwise.

[0016] In an exemplary embodiment, a sampling pattern is superimposed on the low-resolution pixels before or during imaging the mask layer, such that only a portion of the low-resolution imaging pixels are imaged. This may be preferred in some applications, but in many applications good results may be obtained when the sampling pattern is not superimposed on the low-resolution pixels before or during imaging the mask layer.

[0017] It should further be noted that the sampling pattern may be applied within some regions of the modified image file and not applied within other regions. For example, the sampling pattern may be added in very large solid areas, while in other smaller areas the sampling pattern may not need to be superimposed.

[0018] Alternatively or additionally, before generating, a sampling pattern is superimposed on the pixels of the image file to obtain a sample image file in which a portion of the imaging pixels of the image file is changed to non-imaging pixels, and the generating is based on the sampled image file. Thus, the sampling pattern may be added to the original image file before the resolution is decreased. Also in that case, the sampling pattern may be applied within a partial area of the original image file and not applied within other areas. Further, the sampling pattern used for the original image file may be different from the sampling pattern used for the modified image file. Typically, since the resolution has already been decreased, it is preferable to use a relatively dense sampling pattern such as a checkerboard pattern for the modified image file, while a less dense sampling pattern may be used for the original image file.

[0019] Preferably, the sampling pattern is a repetition of blocks in which one or more imaging pixels are combined with one or more non-imaging pixels. Alternating non-imaging pixels and imaging pixels throughout the block results in regular sampling, i.e., a regular selection of imaging pixels throughout the block. For example, the sampling pattern may be a single pixel pattern such as a single pixel checkerboard pattern, a pattern in which each imaging pixel is surrounded by eight non-imaging pixels, for example, a multiple pixel pattern such as a multiple pixel checkerboard pattern where a cluster of four imaging pixels or four non-imaging pixels corresponds to the checkerboard case, a linear pattern, a dash pattern (such as a broken line), a circular pattern, a lattice pattern, or any one or a combination of them.

[0020] According to an exemplary embodiment, imaging is performed such that all imaged spots have substantially the same dimensions and / or shape. According to another exemplary embodiment, imaging is performed such that the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern. Such different dimensions and / or shapes can be achieved by controlling imaging settings, in particular, the following imaging settings: - The intensity value used to generate an imaged feature corresponding to a low-resolution imaging pixel, for example, the intensity value for controlling the beam used for imaging a low-resolution imaging pixel in a solid area, - The time interval used to generate an imaged feature corresponding to a low-resolution imaging pixel, for example, the on-time value for controlling the beam used for imaging a low-resolution imaging pixel in a solid area, - The beam diameter value or beam shape value for controlling the beam used for imaging a low-resolution imaging pixel, - The number of passes used for imaging a low-resolution imaging pixel in a solid area, - The indication of the exposure head of a plurality of exposure heads used to generate an imaged feature or group of imaged features corresponding to a pixel or group of pixels of a low-resolution imaging pixel by controlling any one or more of the above.

[0021] According to an exemplary embodiment, the modified image file is generated such that the modified image file has at least two bits per low-resolution pixel, and the at least two bits indicate, for each low-resolution pixel, whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged in a first imaging setting, a low-resolution imaging pixel imaged in a second imaging setting different from the first imaging setting, optionally, a low-resolution imaging pixel imaged in a third imaging setting different from the first and second imaging settings, and imaging is performed based on the modified image file. These features integrate the indication of the imaging settings used into a single modified image file. In this case, during imaging of the mask layer, information can be extracted from this modified image file without the need to reference other files and / or without the need to have multiple raster image files. Thus, by generating such a modified imaging file, the imager can be instructed in a convenient way while enabling the change of imaging settings. In this way, the imaging settings can be conveniently changed during imaging.

[0022] According to an exemplary embodiment, the method further includes detecting at least one solid area and at least one halftone area in the image file, generating is performed based on the pixels of the at least one solid area, and the modified image file is used to image the at least one solid area. If any halftone areas are present, such areas can be imaged in a different manner, for example, based on an image file of a first resolution, optionally by applying a sampling pattern over the at least one halftone area.

[0023] According to another exemplary embodiment, the method further includes detecting at least one internal region and at least one edge region in the image file, and generating the modified image file is performed based on the pixels of the at least one internal region, and the modified image file is used to image the at least one internal region. The at least one internal region and the at least one edge region may include the internal region and the edge region of the solid region, and / or the internal region and the edge region of the dots of the halftone region. One or more edge regions may be imaged in different ways, for example, based on the image file of the first resolution.

[0024] According to another exemplary embodiment, the method further includes detecting at least one internal region and at least one edge region in the modified image file. Optionally, the sampling pattern may be applied at least on the internal region, and on at least one edge region, the sampling pattern may not be applied or a different sampling pattern may be applied. Additionally or alternatively, one or more edge regions may be imaged in different ways, for example, using different imaging settings compared to one or more internal regions. The at least one internal region and the at least one edge region may include the internal region and the edge region of the solid region, and / or the internal region and the edge region of the dots of the halftone region.

[0025] Preferably, the image file is a raster image file. The raster image file may be a 1BPP (1 bit per pixel) file or a multi-level image file having multiple bits per pixel (so that pixels can have various gradations). The raster image file may have any one of file formats such as TIFF, LEN, JPEG, JPG, BMP, JDF, PNG.

[0026] In an exemplary embodiment, a raster image processing (RIP) module converts a source image file, such as a pdf file or a ps file, into a raster image file corresponding to an image file having the first resolution R1 described above. The RIP module is a component used in image processing that generates a raster image file, also known as a bitmap, which is a pixel-based format. The source image file may be a page description in a high-level page description language such as PostScript, Portable Document Format, XPS, or another bitmap. In the latter case, the RIP applies either a smoothing algorithm or an interpolation algorithm to the input bitmap to generate an output bitmap. Raster image processing is, for example, a process of converting vector digital information, such as a PostScript file, into a high-resolution raster image file. Usually, the RIP module is implemented either as a software component of an operating system or as a firmware program executed on a microprocessor. The RIP module may further have a layout function. If it is necessary to print a plurality of small images, those images may be grouped according to a printing pattern. This grouping may also be performed by the RIP module.

[0027] Optionally, the raster image file may include raster image processing data, i.e., bitmap data, and vector coordinates corresponding to the image patches. Alternatively, a raster image file having raster image processing data may be part of a job file that further includes vector coordinates. The raster image processing data, i.e., bitmap data, and the associated vector coordinates corresponding to the image patches may be used as input for processing the raster image processing data to automatically create one or more raster image processing image patches. One or more pins may be attached to each such image patch, and the one or more image patches having pins and the corresponding vector coordinates of each image patch may be stored in a processing file for creating a printing plate. Also, implementation device information, barcodes, and other information may be associated with and stored in the processing file. In one embodiment, the bitmap information may be stored in a first layer of a template file, and the vector coordinates of each image patch may be stored in a second layer of the template file. In another embodiment, the bitmap information may be stored in a first file, and the vector coordinates of each image patch may be stored in a second file associated with the first file.

[0028] According to a third aspect, a method for imaging a mask layer, comprising the steps of providing a mask layer, receiving an image source file, based on the image source file, generating a first raster image file including imaging pixels and non-imaging pixels at a first resolution R1, and a second raster image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2, the step of generating, imaging the mask layer based on the second raster image file such that the imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2. The mask layer may be further imaged based on the first raster image file, typically in a different pass, preferably such that the imaged spot has a maximum dimension smaller than (√2*P1), more preferably smaller than P1.

[0029] The preferred ranges and values of R2 and R1 disclosed above for the first and second aspects are equally applicable to the third aspect and the aspects below. Also, the sampling pattern may be superimposed on the pixels of the first and / or second raster image files. The sampling pattern may be any one of the patterns disclosed above. Also, imaging based on the second raster image file may be performed such that all the imaged spots generated have substantially the same dimensions and / or shape, or such that the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern. Further, imaging based on the first raster image file may be performed such that all the imaged spots have the same dimensions and / or shape (which may be the same as or different from the imaged spots generated based on the second raster image file), or such that the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern (which may be the same as or different from the pattern used in combination with the second raster image file).

[0030] The source image file may be a page description in a high-level page description language such as PostScript, Portable Document Format, XPS, etc. The first and / or second raster image files may be 1BPP (1 bit per pixel) files or multi-level image files having multiple bits per pixel (e.g., so that the pixels can have various gray levels). The first and / or second raster image files may have any one of file formats such as TIFF, LEN, JPEG, JPG, BMP, JDF, PNG, etc.

[0031] Optionally, the first raster image file and / or the second raster image file are generated such that the first raster image file and / or the second raster image file have at least two bits per pixel, and the at least two bits indicate, for each pixel, whether the pixel is - a non-imaging pixel, - an imaging pixel imaged in a first imaging setting, - an imaging pixel imaged in a second imaging setting different from the first imaging setting, - optionally, an imaging pixel imaged in a third imaging setting different from the first and second imaging settings and imaging is performed based on the first and second raster image files. - Imaging is performed based on the first and second raster image files.

[0032] The invention further relates to a mask layer obtained by the method of any one of the foregoing embodiments.

[0033] Optionally, the mask layer is provided on the photopolymerizable layer of the relief master as an integral part of the relief master. After 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. The invention further relates to a relief structure obtained by this method. The relief master may be a master of an element selected from the group including a flexographic printing plate, a relief printing plate, a letterpress plate, an intaglio plate, a (flexible) printed circuit board, an electronic element, a microfluidic element, a microreactor, a electrophoresis cell, a photonic crystal and an optical element, and a Fresnel lens.

[0034] The mask layer can be a separate layer applied to the relief master, typically after removal of an optionally present protective layer, or can be an integral layer of the master, in contact with one of the relief layer or an optional layer above the relief layer and covered by a potentially present protective layer. The mask layer can also be, for example, a commercially available negative that can be produced by a photographic process based on silver halide chemistry. The mask layer can be a composite layer material in which a transparent layer is produced within a layer that would otherwise be an opaque layer by image-based exposure, as described, for example, in EP 3139210 A1, EP 1735664 B1, EP 2987030 A1, EP 2313270 B1. This can be carried out by ablation of an opaque layer on a transparent carrier layer, as described, for example, in US 6,916,596 B1, EP 816920 B1, or by selectively applying an opaque layer to a transparent carrier layer, as described in EP 992846 B1, or can be written directly onto the relief-forming layer, for example, by printing with an opaque ink, such as by inkjet, as described in EP 1195645 A1.

[0035] Preferably, the mask layer is an integral layer of the relief master, and is positioned to be in direct contact with the relief-forming layer, or preferably a functional layer disposed on the relief-forming layer which is a barrier layer. Further, the integral mask layer can be imaged by ablation and can further be 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 that generates an image-based structured mask used to transfer the structure to the relief master. For this purpose, this layer can be opaque in the UV range and can absorb radiation in the visible IR range, thereby causing heating of the layer and ablation of the layer. After ablation, the mask layer also typically represents a relief with a lower relief height, for example in the range of 0.1 to 5 μm. In an exemplary embodiment, the optical density of the mask layer in the UV range of 330 to 420 nm and / or in the visible IR range of 340 to 660 nm is in the range of 1 to 5, preferably in the range of 1.5 to 4, particularly preferably in the range of 2 to 4. The layer thickness of the laser-ablatable mask layer is generally 0.1 to 5 μm. Preferably, the layer thickness is 0.3 to 4 μm, particularly preferably 1 μm to 3 μm. The laser sensitivity of the mask layer (measured as the energy required to ablate 1 cm2 of the layer) can be 0.1 to 10 mJ / cm2, preferably 0.3 to 5 mJ / cm2, particularly preferably 0.5 to 5 mJ / cm2.

[0036] According to another aspect, there is provided a computer program or a computer program product or a digital storage means comprising computer-executable instructions which, when the program is executed on a computer, control the method of any one of the above-described embodiments.

[0037] According to a further aspect, receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1, and based on the image file, generating a modified image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, or generating signals corresponding to the low-resolution imaging pixels and low-resolution non-imaging pixels at the second resolution R2, wherein a second pitch P2 corresponds to the second resolution R2, and based on the generated modified image file or the generated signals, controlling the imaging of a mask layer such that the imaged spots have a maximum dimension smaller than (√2*P2), preferably smaller than P2, a control module is provided which is configured to perform this.

[0038] The technical advantages described above for the embodiments according to the first and second aspects are applicable to embodiments of the control module with appropriate modifications.

[0039] Preferably, the control module is configured to determine that the low-resolution pixels of the modified image file are low-resolution imaging pixels if the low-resolution pixels contain more or the same number of imaging pixels than non-imaging pixels within the image file, and to determine that the low-resolution pixels are low-resolution non-imaging pixels otherwise.

[0040] Preferably, the control module is configured to superimpose a sampling pattern on the low-resolution pixels, such that only a portion of the low-resolution imaging pixels are imaged. Preferably, the control module is configured to control the imaging such that all imaged spots have substantially the same dimension and / or shape, or such that the dimension and / or shape of the imaged spots are changed according to a regular or irregular pattern.

[0041] Preferably, the control module generates a modified image file having at least two bits per low-resolution pixel based on the image file, wherein the at least two bits indicate, for each low-resolution pixel, whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged in a first imaging setting, a low-resolution imaging pixel imaged in a second imaging setting different from the first imaging setting, and optionally, a low-resolution imaging pixel imaged in a third imaging setting different from the first and second imaging settings, and controls imaging based on the modified image file.

[0042] According to another aspect, there is provided a control module configured to receive an image source file, generate, based on the image source file, a first raster image file including imaging pixels and non-imaging pixels at a first resolution R1, and a second raster image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2, and control imaging of a mask layer such that an imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2, based on the second raster image file.

[0043] The control module may be further configured to control imaging based on the first raster image file, typically in different imaging paths, such that an imaged spot preferably has a maximum dimension smaller than (√2*P1), more preferably smaller than P1.

[0044] Further, the control module may be configured to superimpose a sampling pattern on the pixels of the first and / or second raster image files. The sampling pattern may be any one of the patterns disclosed above. Also, the control module may be configured to control the imaging based on the second raster image file such that all imaged spots generated have substantially the same dimensions and / or shape, or such that the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern. Further, the control module may be configured to control the imaging based on the first raster image file such that all imaged spots have the same dimensions and / or shape (which may be the same as or different from the imaged spots generated based on the second raster image file), or such that the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern (which may be the same as or different from the pattern used in combination with the second raster image file).

[0045] Optionally, the control module may be configured to generate the first raster image file and / or the second raster image file such that the first raster image file and / or the second raster image file have at least two bits per pixel, the at least two bits indicating, for each pixel, whether the pixel is a non-imaging pixel, an imaging pixel imaged in a first imaging setting, an imaging pixel imaged in a second imaging setting different from the first imaging setting, and optionally, an imaging pixel imaged in a third imaging setting different from the first and second imaging settings, and the imaging is controlled based on the first and second raster image files.

[0046] According to a further aspect, there is provided a system for processing a relief master, comprising an imager configured to image a mask layer, and a control module according to any one of the above-described embodiments for controlling the imager. The imager can be a device that selectively removes a part of the mask layer, changes the transmittance of the mask layer, or selectively adds an opaque material to the substrate layer or the relief master. Preferably, the imager removes a part of the mask layer or changes the transmittance of the mask layer, which can be achieved by using a beam of electromagnetic radiation. Most preferably, the imager removes a part of the mask layer by ablation in which a beam of electromagnetic radiation is employed. Preferably, the wavelength of the beam of electromagnetic radiation is in the range of 700 nm to 12,000 nm.

[0047] Optionally, the system further comprises at least one of the following: a 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 developing means configured to remove at least a part of the non-exposed material from the relief master, a drying system, a post-exposure device, a cutting device, a mounting station, a heater.

[0048] According to a further aspect of the present invention, there is provided a system having a user interface for presenting a user with a selection between different imaging methods, preferably including the imaging method of the first aspect and / or the second aspect and / or the third aspect. Optionally, the system may be configured to query the imager to obtain information about the capabilities of the imager (e.g., information regarding the supported imaging methods, the supported resolution, possible settings of the imaging beam, etc.), and based on the obtained information, the information presented to the user by the user interface may be adapted.

[0049] The accompanying drawings are used to illustrate presently preferred, non-limiting and exemplary embodiments of the method, control module, and system of the present invention. The above and other advantages of the features and objects of the present invention will become more apparent when read in conjunction with the accompanying drawings, and the present invention will be better understood from the following detailed description.

Brief Description of the Drawings

[0050]

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DETAILED DESCRIPTION OF THE INVENTION

[0051] Figures 1, 3, and 4 show different illustrative embodiments of a method for imaging a mask layer, particularly the regions of the mask layer corresponding to solid areas. In Figures 1, 3, and 4, the solid areas are circular regions, but those skilled in the art will understand that this region can have any shape.

[0052] In the first step of the methods of FIGS. 1, 3, and 4, an image file including imaging pixels and non-imaging pixels at a first resolution R1. The imaging pixels are represented by black squares. In the second step of FIGS. 1, 3, and 4, a modified image file is generated based on the image file having the first resolution. The modified image file includes low-resolution imaging pixels (shown in black) and low-resolution non-imaging pixels at a second resolution R2 that is lower than the first resolution R1. A first pitch P1 corresponds to the first resolution R1, and a second pitch P2 corresponds to the second resolution R2. Generating may include determining that a low-resolution pixel of the modified image file is a low-resolution imaging pixel if the low-resolution pixel contains as many or more imaging pixels than non-imaging pixels within the image file, and determining that the low-resolution pixel is a low-resolution non-imaging pixel if not.

[0053] In this example, R1 is 2540 dpi corresponding to a pitch of, for example, 10 microns, and R2 is 1270 dpi having a pitch of 20 microns. However, these values may be different in other examples. Another example is R1 = 5080 dpi and R2 = 2540 dpi or R2 = 5080 / 3 dpi or R2 = 1270 dpi. Preferably, the second resolution R2 is less than 2 / 3 of the first resolution R1, more preferably less than or equal to half of the first resolution R1, and / or preferably less than or equal to 1 / 3 of the first resolution R1, except when the first resolution R1 is high enough to allow for further reduction in resolution.

[0054] Optionally, in the following steps shown in FIGS. 3 and 4, prior to or during imaging of the mask layer, a sampling pattern is superimposed on the low-resolution pixels, such that only a portion of the low-resolution imaging pixels are imaged. In FIG. 3, the sampling pattern is added to the modified image file prior to imaging, while in FIG. 4, the sampling pattern is added "on the fly" during imaging. In the embodiment of FIG. 1, the sampling pattern is not superimposed on the low-resolution pixels prior to or during imaging of the mask layer. In yet other embodiments not shown, a sampled image file may be obtained in which the sampling pattern is superimposed on the pixels of the image file such that a portion of the imaging pixels of the image file are changed to non-imaging pixels, and generation of the modified image file is based on the sampled image file.

[0055] Preferably, the sampling pattern is a repetition of blocks in which one or more imaging pixels are combined with one or more non-imaging pixels. In the examples of FIGS. 3 and 4, a checkerboard sampling pattern is used. However, other sampling patterns may be used. FIGS. 6A through 6E show different sampling patterns that may be used. FIG. 6A is a single pixel pattern, here a single pixel checkerboard pattern. FIG. 6B is a multiple pixel pattern, here a two pixel checkerboard pattern. FIG. 6C is a two pixel linear pattern. FIG. 6D is another linear pattern that includes lines aligned with a row or column of pixels. FIG. 6E is a grid pattern that includes lines aligned with a row of pixels and lines aligned with a column of pixels. Preferably, the sampling pattern is a fairly high density pattern when applied to a modified lower resolution file. However, when the sampling pattern is applied to an image file having a first resolution, a lower density sampling pattern may also be used, such as a pattern in which each imaging pixel is surrounded by at least eight non-imaging pixels.

[0056] In the final step of the embodiments of FIGS. 1, 3, and 4, the mask layer is imaged using the modified image file such that the imaged spots have a maximum dimension that is less than (√2*P2), preferably less than P2. For example, in the illustrated example, the imaged spots can have a size of less than 28*28 microns, more preferably less than 20*20 microns. More preferably, the imaging is performed such that the maximum dimension of the imaged spots is less than 1 / 3*P1 + 2 / 3*P2, even more preferably less than (P1 + P2) / 2, or even less than P1, and preferably greater than P1 / 2. The imaging can be performed such that all the imaged spots have substantially the same dimensions and shapes as those shown in FIGS. 1, 3, and 4. FIGS. 2A through 2E show further examples of how the shape and / or size of the image spots can be controlled. FIG. 2A corresponds to that shown in FIGS. 1, 3, and 4, where the diameter D of the spot is well below P2 and further less than P1. In the example of FIG. 2B, D is equal to P2, such that the imaged spots touch each other, and in the example of FIG. 2C, D is greater than P2 and the imaged spots overlap. In the example of FIG. 2D, the imaging was performed such that the dimensions and / or shape of the imaged spots were changed according to a regular or irregular pattern. Further, as shown in FIG. 2E, the positions of the imaged spots can also be changed relative to each other. All the pixels in a row and / or column can be aligned as in FIGS. 2A through 2C, or some of the pixels can be shifted away from the center position as in FIG. 2E.

[0057] According to an exemplary embodiment, the modified image file is generated such that the modified image file has at least two bits per low-resolution pixel, and the at least two bits indicate, for each low-resolution pixel, whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged in a first imaging setting, a low-resolution imaging pixel imaged in a second imaging setting different from the first imaging setting, and optionally, one of the low-resolution imaging pixels imaged in a third imaging setting different from the first and second imaging settings, and imaging is performed based on the modified image file. For example, the first imaging setting may represent a first diameter of the imaged spot and / or a first shape of the imaged spot and / or a first position of the imaged spot, and the second imaging setting may represent a second diameter of the imaged spot and / or a second shape of the imaged spot and / or a second position of the imaged spot, and so on.

[0058] Figures 5A and 5B show a printing plate having a relief 36 with a fine surface structure including mounds 36a and valleys 36b (typically having a depth of 0.5 μm to 20 μm) obtained using an embodiment of the method disclosed above. The printing plate of Figure 5A was obtained using a method similar to the method described above in connection with Figure 1, and no sampling pattern was added. Figure 5A shows a round relief 36 surrounded by another relief 36. For completeness, Figure 1 shows an example that results in a single ring-shaped relief, while Figure 4A shows an example having two reliefs with a shape complementary to the ring shape of Figure 1, but it should be noted that these are merely examples and the reliefs may have any desired shape. There is a non-printing area in the form of a deep valley 37 having a depth (typically 30 μm to 4 mm), which is significantly greater than the depth of the small valleys 36b of the surface structure on the relief 36, between the two reliefs 36. The printing plate of Figure 5B was obtained using a method similar to the method described above in connection with Figure 3, and a sampling pattern was added. Figure 5B shows a round relief 36 surrounded by another relief 36. There is a non-printing area in the form of a ring-shaped deep valley 37 having a depth (typically 30 μm to 4 mm), which is significantly greater than the depth of the small valleys 36b of the surface structure on the relief 36 (typically having a depth of 0.5 μm to 20 μm), between the two reliefs 36.

[0059] According to one embodiment, the depth of the valleys of the surface structure on the solid relief 36 is 0.5 μm to 20 μm, preferably 1 to 10 μm, more preferably 3 to 10 μm. According to one embodiment, the depth of the valleys of the surface structure on the halftone dots (not shown in FIGS. 5A and 5B, but which can be combined with the solid reliefs of FIGS. 5A and 5B) is 0.5 μm to 20 μm, preferably 1 to 10 μm, more preferably 3 to 10 μm. The total relief depth (i.e., the maximum relief depth in a wide area where no imaging pixels are present) is preferably 100 μm to 4 mm, more preferably 100 μm to 2 mm, and most preferably 100 μm to 1 mm. The intermediate relief depth (i.e., when present, the relief depth of the area between the halftone dots (not shown in FIGS. 5A and 5B)) is preferably 40 to 60% of the total intermediate depth, for example 30 μm to 2 mm, more preferably 40 μm to 1 mm. According to one embodiment, after the exposure and development of the relief master, a solid printing relief 36 having a first surface structure of mounds surrounded by valleys is generated within the solid area, and a plurality of halftone dots (not shown) having a second surface structure of mounds surrounded by valleys are generated within the halftone area.

[0060] FIG. 7 shows a system for transferring from a relief master to a relief printing plate or sleeve. The system includes a control module 100, an imager 110, an exposure means 120, and a development means 130. Using a modified image file and / or imaging instructions generated by the control module 100, after the mask layer on the master is imaged by the imager 110, the master is exposed to electromagnetic radiation in the exposure means 120 through the imaged mask layer, as a result of which a portion of the photosensitive layer 16 is cured. The electromagnetic radiation may have a wavelength in the range of 200 to 2000 nm, and is preferably ultraviolet (UV) radiation having a wavelength in the range of 200 to 450 nm.

[0061] Electromagnetic radiation changes the properties of the exposed portions of the photosensitive layer 16 such that the unexposed portions of the photosensitive layer are removed by the developing means 130 and a relief printing plate or sleeve is formed in the following developing means. Preferably, development is achieved by treatment with a liquid (solvent, water, or aqueous solution), where the liquefied or softened material is removed.

[0062] Treatment with a liquid can be carried out by spraying the liquid onto the original plate or by brushing or scrubbing the original plate in the presence of the liquid. The nature of the liquid used depends on the nature of the original plate employed. If the layer to be removed is soluble, emulsifiable, or dispersible in water or an aqueous solution, water or an aqueous solution can be used. If the layer is soluble, emulsifiable, or dispersible in an organic solvent or mixture, an organic solvent or mixture can be used.

[0063] For thermal development, a thermal development means in which a flexible plate is fixed on a rotating drum may be used. The thermal development means further comprises an assembly for heating at least one additional layer and a further assembly for bringing the outer surface of the at least one heated additional layer into contact with an absorbent material for absorbing the molten material. The assembly for heating may comprise a heatable underlay for the flexible plate and / or an IR lamp disposed 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 continuously moved across the surface of the flexible plate while repeatedly removing the material of the at least one additional layer while the drum is rotating. In this way, the molten material is removed, but the non-molten regions remain to form a relief.

[0064] The relief printing plate or sleeve 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 the various units of the imaging system. Optionally, one or more preprocessing modules, such as a raster image processing (RIP) module that converts an image file, such as a pdf file, into a raster image process file, may be provided upstream of the control module 100 as also seen in FIG. 8 described below.

[0065] FIG. 8 shows an exemplary embodiment of a control module 100 disposed downstream of a raster image processing module 90. The raster image processing (RIP) module 90 converts a source image file, such as a pdf or ps or xps file, into a raster image file (also called a bitmap) at a first resolution R1. Raster image processing is a process of converting vector digital information, such as a PostScript file, into a high-resolution raster image file. Typically, the RIP module 90 is implemented either as a software component of an operating system or as a firmware program executed on a microprocessor. The RIP module 90 may further have a layout function. When it is necessary to print a plurality of small images, those images may be grouped according to a printing pattern. This grouping may also be performed by the RIP module 90.

[0066] The control module 100 receives an image file including imaging pixels and non-imaging pixels at a first resolution R1, and based on the image file, generates a modified image file corresponding to low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, and based on the modified image file, is configured to control the imager 110 such that the imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2.

[0067] FIG. 9 shows an alternative embodiment of the control module 100. In this embodiment, the raster image processing module 90 is included within the control module. The image source file is typically a first raster image file having a first resolution R1, such as 5080 dpi or 2540 dpi, for one or more halftone regions to be printed, typically in color, and a second raster image process file having a lower second resolution R2 (corresponding to a second pitch P2), such as 1016 dpi, for one or more solid regions to be printed, such as one or more solid white regions. This is the raster image to be processed to generate. In this example, it is assumed that there is a need to print a solid white region, but the same method can be used when there is a need to print one or more solid regions of a specific color. Optionally, the sampling pattern may be superimposed on the first and / or second raster image files. The resulting raster image file is then such that the low-resolution imaging pixels of the solid white region result in an imaged spot having a maximum dimension smaller than (√2*P2), preferably smaller than P2, and the halftone region results in an imaged spot having a maximum dimension that can be larger than or smaller than P1, and is typically transmitted to the imager 110 in two different passes to perform imaging according to the first and second raster image files.

[0068] FIG. 10 shows a further exemplary embodiment of a method for imaging a mask layer. When an image file having a first resolution R1 is received, first, the image file is analyzed to detect any solid regions and any halftone regions within the image file. Next, based on the pixels of at least one solid region, a first modified image file having a second resolution R2 lower than the first resolution R1 is generated, and based on the pixels of at least one halftone region, a second modified image file having the first resolution R1 is generated. During a first pass, at least one halftone region 34 can be imaged using the second modified image file having the first resolution R1, as seen on the left side of FIG. 10, and during a second pass, at least one solid region 32 can be imaged using the first modified image file having the second lower resolution R2, as seen on the right side of FIG. 10. For illustrative purposes, some portions (10%, 30%, and 70%) of the halftone region are shown, but those skilled in the art will understand that any combination of halftone regions can exist. As shown, the diameters d1, d2, d3 of the imaged spots 41 can vary depending on the dot size of the respective halftone regions 34. Typically, the diameter d4 of the imaged spot 40 within the solid region 32 may be larger than the diameter of the imaged spots within the halftone region.

[0069] For example, for small tone values, e.g., 0 to 10%, a first diameter d1 may be used, and as a result, as seen in the upper left image of FIG. 10 and in FIGS. 2B and 2C, imaged spots 41 that are in contact or overlap are obtained. As seen in the central and lower left images of FIG. 10, for larger tone values, e.g., 10 to 50%, a second diameter d2 that is smaller than d1 may be used, and as a result, the imaged spots 41 do not overlap. For even larger tone values, e.g., 50 to 99%, an even smaller diameter d3 < d2 may be used. Alternatively, a sampling pattern may be used for even larger tone values in combination with a larger diameter. In the solid zone 32 (100%), the sampling pattern may be combined with a diameter d4 > d1 but preferably smaller than P2, as seen in the imaged spots 40 in the right image of FIG. 10 and as seen in FIGS. 2A, 2D, or 2E.

[0070] Embodiments of the present invention are particularly useful for standard amplitude modulation (AM) screens where the distance Dd between adjacent dots in the halftone region is the same for halftone regions having different tone values. In this case, the tone value of the halftone region is determined by the size of the group of clustered imaged pixels (i.e., the dot size) corresponding to the clustered imaged spots 41. However, those skilled in the art will understand that other embodiments of the present invention may be used for frequency modulation (FM) screens or AM and FM screens where the distance Dd is not constant.

[0071] FIG. 11 shows a further exemplary embodiment of a method for imaging a mask layer. When an image file having a first resolution R1 is received, first, as seen in the image on the left side of FIG. 11, a modified image file having a second resolution R2 lower than R1 is generated. Next, the image file is analyzed to detect at least one internal region and at least one edge region within the image file, and a sampling pattern is applied to at least one internal region. Next, the modified image file including the sampling pattern within at least one internal region is used to image at least one internal region. The imaging settings used in the internal region may be the same as or different from the imaging settings used in the edge region. Optionally, the modified image file may have at least two bits per low-resolution pixel, and the at least two bits indicate, for each low-resolution pixel, whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged with a first imaging setting, a low-resolution imaging pixel imaged with a second imaging setting different from the first imaging setting, and optionally, a low-resolution imaging pixel imaged with a third imaging setting different from the first and second imaging settings, In another example (not shown), the detection of at least one internal region and at least one edge region may be performed within the original image file, and the sampling pattern may be applied on the original image file before the resolution is reduced. The at least one internal region and the at least one edge region may include the internal region and the edge region of the solid region, and / or the internal region and the edge region of the dots of the halftone region.

[0072] Those skilled in the art will readily recognize that the steps of the various methods described above can be performed by a programmed computer. In this specification, some embodiments also contemplate a program storage device, such as a digital data storage medium, that is machine or computer readable and encodes a machine-executable program or a computer-executable program of instructions, the instructions performing some or all of the steps of the methods described above. The program storage device may be, for example, a digital memory, a magnetic storage medium such as magnetic disks and magnetic tapes, a hard drive, or an optically readable digital data storage medium. Embodiments also contemplate a computer programmed to perform the above-described steps of the method.

[0073] Although the principles of the invention have been described above in connection with specific embodiments, it is to be understood that this description is made by way of example only and not as a limitation on the scope of protection determined by the appended claims.

Claims

1. A method for imaging a mask layer, comprising: providing the mask layer; receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1; generating a modified image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2; imaging the mask layer based on the modified image file such that an imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2. A method as described above.

2. A method for imaging a mask layer, comprising: providing the mask layer; receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1; generating signals corresponding to low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2; imaging the mask layer based on the signals such that an imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2. A method as described above.

3. The method according to claim 1 or 2, wherein the image file is a raster image file.

4. The modified image file is generated such that the modified image file has at least two bits per low-resolution pixel, and the at least two bits indicate, for each low-resolution pixel, whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged in a first imaging setting, a low-resolution imaging pixel imaged in a second imaging setting different from the first imaging setting, optionally, a low-resolution imaging pixel imaged in a third imaging setting different from the first and second imaging settings. ​ The imaging step is performed based on the corrected image file, The method according to claim 1 or 3.

5. A step of detecting at least one solid area and at least one halftone area in the image file, wherein the step of generating the corrected image file is performed based on pixels of the at least one solid area, and the corrected image file is used to image the at least one solid area, the detecting step, or A step of detecting at least one internal area and at least one edge area in the image file, wherein the step of generating the corrected image file is performed based on pixels of the at least one internal area, and the corrected image file is used to image the at least one internal area, the detecting step The method according to claim 1 or 3, further comprising.

6. The generating step includes a step of determining that a low-resolution pixel of the corrected image file is a low-resolution imaging pixel when the low-resolution pixel contains more or the same number of imaging pixels as non-imaging pixels in the image file, and determining that the low-resolution pixel is a low-resolution non-imaging pixel otherwise. The method according to any one of claims 1 to 5.

7. Before the generating step, a sampling pattern is superimposed on the pixels of the image file to obtain a sample image file in which a part of the imaging pixels of the image file is changed to non-imaging pixels, and the generating step is based on the sampled image file. The method according to any one of claims 1 to 6.

8. A method for imaging a mask layer, The step of providing the mask layer; The step of receiving an image source file; Generating a first raster image file including imaging pixels and non-imaging pixels at a first resolution R1 and a second raster image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2. Imaging the mask layer based on the second raster image file such that the imaged spot has a maximum dimension smaller than (√2 * P2), preferably smaller than P2. A method comprising the above steps. **Claim 9** The first raster image file and / or the second raster image file are generated such that the first raster image file and / or the second raster image file have at least two bits per pixel, and the at least two bits indicate, for each pixel, whether the pixel is a non-imaging pixel, an imaging pixel imaged in a first imaging setting, an imaging pixel imaged in a second imaging setting different from the first imaging setting, optionally, an imaging pixel imaged in a third imaging setting different from the first and second imaging settings. Whether it is one of them. The imaging step is performed based on the first and second raster image files. The method according to claim 8. **Claim 10** The first pitch P1 corresponds to the first resolution R1, and the imaging step is performed such that the maximum dimension of the imaged spot is smaller than 1 / 3 * P1 + 2 / 3 * P2, preferably smaller than (P1 + P2) / 2, or even smaller than P1, and preferably larger than P1 / 2. The method according to any one of claims 1 to 9. **Claim 11** The second resolution R2 is less than 2 / 3 of the first resolution R1, preferably less than or equal to half of the first resolution R1, and / or preferably less than or equal to one-third of the first resolution R1. The method according to any one of claims 1 to 10. **Claim 12** Before the step of imaging the mask layer or during the step of imaging, a sampling pattern is superimposed on the low-resolution pixels, such that only a portion of the low-resolution imaging pixels are imaged. The method according to any one of claims 1 to 11.

13. The method according to any one of claims 1 to 7, wherein the sampling pattern is not superimposed on the low-resolution pixels before the step of imaging the mask layer or during the step of imaging.

14. The method according to claim 7 or 12, wherein the sampling pattern is a repetition of blocks in which one or more imaging pixels are combined with one or more non-imaging pixels.

15. The method according to claim 7 or 12, wherein the sampling pattern is any one or a combination thereof of a single pixel pattern such as a single pixel checkered pattern, a pattern in which each imaging pixel is surrounded by eight non-imaging pixels, a plurality of pixel patterns such as a plurality of pixel checkered patterns, a linear pattern, a dash pattern, a circular pattern, and a lattice pattern.

16. The method according to any one of claims 1 to 15, wherein the imaging step is performed such that all imaged spots have substantially the same dimensions and / or shape, or the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern.

17. A mask layer obtained by the method according to any one of claims 1 to 16.

18. The method according to any one of claims 1 to 16, wherein the mask layer is provided on a photopolymerizable layer of a relief master, and after the imaging step, the photopolymerizable layer of the relief master is exposed through the mask layer, and the relief master is developed to obtain a relief structure.

19. A relief structure obtained by the method according to claim 18.

20. A computer program, computer program product, or digital storage means comprising computer-executable instructions for controlling the method according to any one of claims 1 to 16 and 18 when the program is executed on a computer.

21. Receiving an image file including imaging pixels and non-imaging pixels at a first resolution R1; Generating a modified image file based on the image file, the modified image file including low-resolution imaging pixels and low-resolution non-imaging pixels at a second resolution R2 lower than the first resolution R1, or generating signals corresponding to the low-resolution imaging pixels and the low-resolution non-imaging pixels at the second resolution R2, wherein a second pitch P2 corresponds to the second resolution R2; Controlling the imaging of a mask layer based on the modified image file or the generated signals such that the imaged spot has a maximum dimension smaller than (√2*P2), preferably smaller than P2; A control module configured to perform the above.

22. The control module according to claim 21, wherein the generating comprises determining that a low-resolution pixel of the modified image file is a low-resolution imaging pixel if the low-resolution pixel contains as many or more imaging pixels than non-imaging pixels within the image file, and determining that the low-resolution pixel is a low-resolution non-imaging pixel otherwise.

23. The control module generating a modified image file having at least two bits per low-resolution pixel based on the image file, the at least two bits indicating for each low-resolution pixel whether the pixel is a low-resolution non-imaging pixel, a low-resolution imaging pixel imaged in a first imaging setting, a low-resolution imaging pixel imaged in a second imaging setting different from the first imaging setting, optionally, a low-resolution imaging pixel imaged in a third imaging setting different from the first and second imaging settings generating to indicate whether it is one of them, and controlling the imaging based on the modified image file, and The control module according to claim 21 or 22, which is configured to perform the above. **Claim 24** Receiving an image source file, and Based on the image source file, generating a first raster image file including imaging pixels and non-imaging pixels with a first resolution R1, and a second raster image file including low-resolution imaging pixels and low-resolution non-imaging pixels with a second resolution R2 lower than the first resolution R1, wherein a second pitch P2 corresponds to the second resolution R2, generating, Controlling the imaging of the mask layer based on the second raster image file such that the imaged spot has a maximum dimension smaller than (√2 * P2), preferably smaller than P2 The control module which is configured to perform the above. **Claim 25** The control module is configured to generate the first raster image file and / or the second raster image file such that the first raster image file and / or the second raster image file have at least two bits per pixel, and the at least two bits indicate, for each pixel, whether the pixel is a non-imaging pixel, an imaging pixel imaged in a first imaging setting, an imaging pixel imaged in a second imaging setting different from the first imaging setting, optionally, an imaging pixel imaged in a third imaging setting different from the first and second imaging settings and the imaging is controlled based on the first and second raster image files. The control module according to claim 24. **Claim 26** A first pitch P1 corresponds to the first resolution R1, and the imaging is performed such that the maximum dimension of the imaged spot is smaller than 1 / 3 * P1 + 2 / 3 * P2, preferably smaller than (P1 + P2) / 2, or even smaller than P1, and preferably larger than P1 / 2. The control module according to any one of claims 21 to 25. **Claim 27** ​ The control module according to any one of claims 21 to 26, wherein the second resolution R2 is less than 2 / 3 of the first resolution R1, preferably less than or equal to half of the first resolution R1, and / or preferably less than or equal to one third of the first resolution R1.

28. The control module according to any one of claims 21 to 27, wherein the control module is configured to superimpose a sampling pattern on the low-resolution pixels, and as a result, only a part of the low-resolution imaging pixels is imaged.

29. The control module according to any one of claims 21 to 28, wherein the control module is configured to control the imaging such that all imaged spots have substantially the same dimensions and / or shape, or the dimensions and / or shape of the imaged spots are changed according to a regular or irregular pattern.

30. An imager configured to image a mask layer A control module according to any one of claims 21 to 29 for controlling the imager A system for processing a relief master, comprising

31. The system according to claim 30, comprising at least one transport system configured to transport the relief master, a storage device, exposure means configured to expose the relief master through the imaged mask layer, development means configured to remove at least a part of the non-exposed material from the relief master, a drying system, a post-exposure device, a cutting device, a mounting station, a heater, or any one or more thereof.

Images