The present invention relates to a method for the manufacture of one or more panels, of the type with at least two layers and of which a said layer is a top layer based on synthetics, wherein a board is formed comprising said layers, and wherein the one or more panels are formed from this board by carrying out one or more processing steps, wherein at least one said processing step is a laser processing, and wherein during this laser processing at least the top layer is exposed to a laser beam of a laser, to form one or more markings.

The present invention also relates to a panel of this kind.

In particular, the invention relates to a method for the manufacture of floor panels, wall panels or furniture panels. The panels are often of the type that has a top layer based on synthetics. It is known that panels of this kind may be of a different structure, thus, these panels may be for example

• laminate panels, wherein the top layer for example comprises a resin- impregnated paper, being a so-called "overlay" or wearing layer: "wear layer";

• parquet panels or veneer parquet panels, comprising a layer of wood on which one or more protective layers, such as varnish coats based on a resin, are applied, to protect the layer of wood. The resin may for example be an acrylic resin, an alkyd resin, a polyurethane resin, a melamine-comprising resin, an acrylate resin, a methacrylate resin, an epoxy resin, a polyester resin, a polyether resin or a mixture of the aforementioned resins. This resin may be a multicomponent resin and/or a thermosetting resin and/or an aqueous dispersion with or without a crosslinking system and/or a UV polymerizing resin. The one or more protective layers form the top layer here;

• panels based on polyvinyl chloride (PVC), such as LVT (luxury vinyl tile), WPC (wood plastic composite), EPC (expanded polymer core), SPC (solid particle core), etc.; • panels comprising a mineral-based substrate, such as a gypsum, magnesium oxide (MgO) or cement-based substrate, and a top layer based on synthetics;

• panels comprising a substrate based on a geopolymer and a top layer based on synthetics;

• panels based on a plastic, wherein this plastic is not PVC, for example based on polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), BMC (bulk molding composition) based on unsaturated polyesters, polycarbonate (PC), acrylonitrile butadiene styrene (ABS), styrene-ethylene-butylene-styrene (SEBS), polylactic acid (PLA), polyvinyl butyral (PVB), etc.

These panels often comprise a pattern, such as a wood pattern or a stone pattern, for example a marble pattern. This pattern may be an imitation wood pattern or stone pattern. Thus, laminate panels or panels based on PVC are provided with a decor, for example a decorative layer in the form of a resin-impregnated printed paper, a printed PVC layer or a print layer largely comprising ink. In the case of parquet panels or veneer parquet panels, use is made of a natural wood layer comprising a real, natural wood pattern. The drawback with the existing panels is that, in the case of an imitated pattern, the panel may look artificial. In the case of parquet panels or veneer parquet panels, the look of the layer of wood, through the application of the one or more protective layers, may be altered so that the look is less aesthetic.

There are already all kinds of techniques for improving the appearance of these panels. However, there is still room for improvement.

WO 2006/063803 describes a floor panel, wherein this floor panel comprises a top layer based on synthetics, and wherein the decorative side of the floor panel imitates a wood pattern, wherein the floor panel has, on its top surface, zones with various degrees of gloss, which extend over the top surface as a function of the imitated overall wood pattern. By working with zones with various degrees of gloss, an extra dimension is added to the floor panel, giving better reproduction of wood species that are difficult to imitate. From WO 01/96689, it is known to provide a relief in the upper side of a laminate product, which may or may not correspond to the decor. This relief is for example applied by means of a press plate provided with a relief. From EP2834076, a laminate product of this kind is known, with a better, i.e. less artificial, appearance.

The present invention relates firstly to an alternative method for the manufacture of panels, of the type with at least two layers and of which a said layer is a top layer based on synthetics, wherein according to various embodiments, solutions are offered for the problems from the prior art.

The invention relates to a method for the manufacture of one or more panels, of the type with at least two layers and of which a said layer is a top layer based on synthetics, wherein a board is formed comprising said layers, and wherein the one or more panels are formed from this board by carrying out one or more processing steps, wherein at least one said processing step is a laser processing and wherein during this laser processing at least the top layer is exposed to a laser beam of a laser, to form one or more markings, and wherein preferably the one or more markings at least form discolorations of the top layer. Said laser may for example be a UV laser or a laser that emits green light, a so- called "green laser". Since at least the top layer is exposed to a laser beam of a laser, at least portions of the top layer are processed during the laser processing, to form the one or more markings. Here, "discolorations" means deviations based on color, relative to the visible color at the level of the top layer prior to the laser processing. Here, the visible color at the level of the top layer means the color that is visible when we look at the upper side of the panel. Said deviations may for example be an intensification of color, for example darker or lighter discolorations, but may also be differences in hues relative to the original visible hue at the level of the marking. The discolorations are thus changes on the basis of hue and/or intensity and/or brightness. Here, the markings are, whether or not separately, easily visible with the naked eye. Thus, it is possible that the markings only alter the overall perception of the panel, but for example it is difficult or impossible to distinguish with the naked eye where precisely the markings have been applied. The discolorations may thus be subtle discolorations that contribute to the general appearance of the panel. A UV laser emits one or more laser beams in the UV spectrum and thus emits light with a wavelength between approximately 100 nm and approximately 400 nm. This relates to high-energy light that is able to process at least the top layer, almost without the formation of additional heat. By means of a UV laser, it is thus possible to work very accurately to apply the desired markings, without damaging the surrounding parts of the panel. In addition, by means of a UV laser, the depth can be set very precisely and markings can even be applied through various layers or sublayers. A UV laser allows precise working at the micron and even the submicron level. For example, at a selected pulse length and spot size, we are able to set the speed and the frequency to obtain the desired markings. A green laser emits one or more laser beams with a wavelength between 495 nm and 570 nm and thus emits visible green light.

By working with a laser to apply markings, also there are no mechanical components that have to come in contact with the top layer in order to apply these markings. The top layer may for example comprise wear-resistant particles, such as corundum or aluminum oxide, which may damage mechanical components and/or cause rapid wear of mechanical components. A UV laser and a green laser require little maintenance. Both are usable at room temperature and/or the temperature prevailing during production of the panels, so that the laser processing per se does not have to take place in another room and/or in a temperature-conditioned room.

It may be chosen to work with very short pulse lengths, for example pulse lengths of some nanoseconds, so as to apply local, fully controlled markings, for example by removing material locally with the laser beam and/or by altering the material structure.

It was found, surprisingly, that a UV laser is particularly suitable for processing top layers based on synthetics. Plastics absorb strongly in the UV spectrum and only absorb at the level of the laser beam, so that surrounding parts are not damaged. The laser may for example be an excimer laser, which for example emits a laser beam with a wavelength between 157 nm and 360 nm. Said markings may be all kinds of types of markings and all kinds of combinations of types of markings are possible, so long as these are not incompatible. Said one or more markings may comprise one or more markings from the following nonexhaustive list, so long as these are not incompatible with each other:

• words and/or logos and/or decorative illustrations. This is for example useful when the panels are floor panels, wall panels or furniture panels that are used in companies or public spaces. Said floor panels, wall panels or furniture panels may also be desirable for providing the interior with eye-catching elements;

• relief-forming markings, such as indentations/recesses. By means of the aforementioned lasers, which for example work with mirrors, pits/spots can be applied selectively, wherein through the choice of the movement of the mirrors, line-shaped indentations, wider indentations, etc. may be applied. By means of such markings, a relief is formed, for example on the upper side of the panels. These markings may also be used for further optimizing/refining the relief present on the upper side of the panels obtained by other relief-producing techniques (embossing techniques), such as relief obtained by means of a press plate or by means of chemical agents. Thus, for example a basic relief may be obtained by means of an embossing technique and then by means of laser processing, this basic relief may be further personalized and/or optimized and/or refined, for example by reworking and/or coloring the existing relief. For example, it may be a question of "embossing-in-register". In this way, the appearance of the panels is optimized/improved;

• relief-accentuating markings. These markings may be used for further optimizing/refining the relief present on the upper side of the panels obtained by other relief-producing techniques (embossing techniques), such as relief obtained by means of a press plate or by means of chemical agents, by specific coloring of the relief. Optionally, these relief-accentuating markings may in addition further adapt/refine the relief.

• accentuating markings, wherein these markings for example accentuate certain components of the wood pattern such as knots, imperfections, pores, etc.;

• colorable markings, such as stainable markings. These colorable markings ensure that pigments or dyes can penetrate into the top layer and/or the laser processing can form colorable indentations by removing material from the top layer or altering the structure of the material in the top layer. Thus, by means of one or more markings, the top layer can be made locally colorable. This is useful if we wish to obtain certain effects. The coloring may even be left up to whoever fits the panels, so that the appearance of the panels is adaptable subsequently;

• roughness-creating markings. These markings impart a certain roughness to the top layer. This may or may not be combined with removal or ablation of the plastic material present in the top layer;

• gloss-producing markings. Thus, for example a mirror effect may be created for example by applying fine lines at close spacing with the laser: as a result, the light is reflected more in a certain direction on the surface and reflection is less in other directions. The direction of reflection can be controlled in a certain direction for each separate part;

• corrective markings. In the case of boards comprising a top layer based on one or more layers of impregnated paper, it is possible that the paper tears during pressing, and therefore imperfections, such as white lines of the paper or even the substrate under the layer comprising the paper, become visible. We may choose to treat the top layer at the level of these imperfections with the laser so as to obtain the desired color;

• subsurface markings. This is then called "subsurface laser engraving", wherein for example color changes are obtained underneath the uppermost surface of the top layer.

Preferably two or more panels are formed from the board. For this purpose the board is sawn or cut. A said processing step is then a sawing step or cutting step for forming two or more base panels, from which the two or more panels are formed by carrying out said remaining processing steps, for example such as a processing step wherein the edges of the base panels are provided with coupling parts so as to be able to couple the panels together. Said laser processing may be carried out prior to said sawing step or cutting step, but preferably takes place after said sawing step or cutting step. The laser processing may for example be the last or one of the last processing steps. Therefore the laser processing is not a limiting factor for the speed with which the other steps can be carried out. It is then also certain that the panel comprises the marking. It is then also easy to choose that not all panels that are formed from a board undergo a said laser processing. This is for example useful if the panels formed from the board all comprise a different wood pattern, wherein for example not all panels comprise a wood pattern with components that must be accentuated. Of course, all panels may comprise at least one said marking.

The laser source of the laser is preferably installed outside the working zone of the laser beam. In such a configuration the laser beam is guided over a stabilized optical path for example to a lens.

In a preferred embodiment, a short focal distance is used, for example a focal distance of less than 10 cm, in such a way that the power of the laser can be concentrated optimally on the top layer of the floor panel. "Focal distance" means the distance from the lens of the laser to the top layer. A focal distance of at least 10 cm may also be chosen, for example to reduce the risk of misting/fouling of the lens.

In a preferred embodiment, the laser beam may be split on its optical path into several laser beams by means of a so-called "beam splitter". By means of several laser beams, the laser processing can be carried out more quickly, without having to provide an additional laser source.

The foregoing does not exclude that in this method, additional laser treatments are carried out with other types of lasers, for example such as a CO2 laser. The processing with another type of laser may or may not take place simultaneously with the laser processing just mentioned. This may for example be useful if we wish to form coupling parts by means of another type of laser, so as to be able to couple the panels together.

According to a first variant embodiment, the invention relates to a method for the manufacture of one or more panels, of the type with at least two layers and of which a said layer is a top layer, wherein a board is formed comprising said layers, and wherein the one or more panels are formed from this board by carrying out one or more processing steps, wherein at least one said processing step is a laser processing, and wherein during this laser processing at least the top layer is exposed to a laser beam of a laser, to form one or more markings, wherein said laser for example is a UV laser or a green laser and wherein preferably the one or more markings at least form discolorations of the top layer. Here, the top layer is or is not based on synthetics. Thus, the top layer may for example be based on an oil. Such panels are for example oiled veneer parquet or oiled parquet. A top layer based on a UV-oil for a veneer parquet or a parquet may be regarded as a top layer comprising a plastic or as a top layer based on synthetics.

According to a second variant embodiment, the invention relates to a method for the manufacture of a floor covering, of the type with one or more layers and of which a said layer is a top layer that is or is not based on synthetics, wherein a base is formed comprising said layers, and wherein one or more processing steps are carried out on this base to form the floor covering, wherein at least one said processing step is a laser processing, and wherein during this laser processing at least the top layer is exposed to a laser beam of a laser, to form one or more markings, wherein said laser is preferably a UV laser or a green laser and wherein preferably the one or more markings at least form discolorations of the top layer. Here, the floor covering may be for example wall-to-wall vinyl or a linoleum floor covering.

According to a third variant embodiment, the invention relates to a method for the manufacture of one or more panels, of the type with at least two layers and of which a said layer is a top layer based on synthetics, wherein a board is formed comprising said layers, and wherein the one or more panels are formed from this board by carrying out one or more processing steps, wherein during a said processing step at least the top layer is processed to form one or more markings, wherein the one or more markings at least form discolorations of the top layer. Said processing step may be a laser processing that provides said discolorations. However, other processing steps that provide discolorations of the top layer are possible. Some examples of such processing steps are: printing with an ink, painting, staining,..., etc. Said processing step is thus a coloring step wherein the top layer is colored locally to form the one or more markings. The additional features of the embodiments described hereunder of the first-mentioned method according to the invention are also combinable with the aforementioned variant embodiments, according to all compatible combinations.

Preferably, the one or more markings form indentations of the top layer, wherein these indentations preferably only open out at the top. Open out at the top means that they open out on the upper side of the top layer, viewed in a height direction that extends perpendicularly to the plane in which the panel extends. In the case of floor panels this height direction usually coincides with the vertical direction. With furniture panels and/or wall panels, this height direction often coincides with the horizontal direction. These indentations are for example obtained with the laser processing by removing material from the top layer and/or by local impressing of the top layer and/or local alteration of the structure of the top layer. By means of the laser, the desired relief may be obtained, and thus the desired appearance. Since the work is carried out here with for example a UV laser or a green laser to form the indentations, the indentations may have all kinds of dimensions, and for example very narrow, thin, smooth and/or serrated indentations may be obtained. The indentations preferably only extend at the level of the top layer, but this does not exclude that the markings may also extend through other layers. Owing to the high accuracy, it can be avoided that the panels have an artificial appearance. These indentations may also form recesses.

The indentations may, for example viewed in a direction perpendicular to a plane that extends along the panel, have a dimension of at most 20 micrometers, preferably at most 10 micrometers. Notwithstanding that these dimensions, seen in the height direction, are small, they still have a great influence on the appearance of the panel. Because these dimensions are small, the laser processing can be carried out sufficiently quickly, while still obtaining the desired end result. If these indentations are obtained by removal of material, only a small amount of material has to be removed, so that for example additional exhaust ventilation and/or a separate material removal step are superfluous. When the top layer comprises a resin-impregnated paper at the top, at these small dimensions the paper is not exposed to the laser beam of the laser. At these small dimensions hardly any indentation can be seen on visual inspection, but for example a color difference or intensification of color is indeed visible.

Preferably, the laser processing is used at least for removing portions of material from the top layer, for example in order to form said indentations. Indentations may also be formed per se, comprising for example an undercut by means of the laser processing. The desired shape of the indentations may for example be obtained by tilting the laser beam, setting and/or positioning the focus of the laser beam relative to the workpiece or the like.

However, material may also be removed by the laser processing over the full thickness of the top layer, preferably in the form of a cut extending through the top layer.

In a specific embodiment, a relief-creating processing takes place prior to said laser processing, wherein during the relief-creating processing the board is provided with a base structure at least at the level of the top layer, wherein said one or more markings further refine and/or accentuate this base structure. Here, the laser processing may for example also be able to remove material for indentations and/or to color indentations that were already present prior to the laser step. These indentations may already be present by carrying out the relief-forming processing step prior to the laser processing, for example by pressing the board with a relief-comprising press plate, a so-called structured press plate, and/or by chemical relief formation (chemical embossing). The laser processing then for example optimizes the structure corresponding to this relief, for example by optimizing the indentations of the structure and/or coloring them, by application of said one or more markings. By means of a relief-comprising press plate, it is already possible to apply a certain structure to the visible side of the panel, but the form of this structure is limited, so that the appearance of the panel may seem artificial. Said laser processing is able to optimize this structure further.

In a particular embodiment, a said marking is applied in such a way that a said panel comprises this marking and so that, seen in a plane that extends according to the panel, this marking is largely surrounded by remaining regions of the top layer. One or more said markings then largely do not extend at the level of an end edge. The laser treatment thus does not relate, or not exclusively, to an "edge treatment" and is used for providing the upper side of the panels with the desired markings. It was found, surprisingly, that a UV laser is especially suitable for applying such markings, because the material of the panel that extends next to the markings is barely affected by the laser beam of the UV laser. Of course, there may be markings at the level of an end edge and/or that are applied at the level of an end edge.

In a specific embodiment, the markings have a white hue, gray hue or black hue. Darker hues are advantageous if the markings are used for example to accentuate knots, the grain, etc. of the wood pattern. White hues are for example advantageous for imitating joints or for imitating veins of a marble pattern. Dark hues and white hues are extremely suitable for obtaining a wenge effect.

In a particular embodiment, pigments are added prior to or during the laser processing. In this way the markings acquire the desired color. Specifically in this particular embodiment, the pigments may be spread on top of the top layer, prior to or during exposure of at least the top layer to the laser beam, so that the pigments that come into contact with the laser beam are fixed in the panel. After exposure of at least the top layer to the laser beam, the remaining pigments that have not been fixed in the panel are removed again. This is a particularly efficient way of providing the markings with the desired color.

In a particular embodiment, the markings, after application thereof, are additionally colored and/or, if the markings are indentations, at least partially filled. This may take place with for example a paint, a stain, a varnish or the like. When the markings are indentations, material may be applied in these indentations beforehand.

In a preferred embodiment, during the laser processing, only material from the top layer is removed. This top layer may comprise one or more layers. When there are several layers, preferably only material removed from the top layer is removed, and/or the one or more markings are only applied at the level of this top layer. This relates to a surface treatment that can be carried out at a sufficient speed.

Preferably, the board comprises a decorative layer that may or may not form part of the top layer, wherein the one or more panels formed also comprise said decorative layer. Thus, the board may for example comprise at least 3 layers, being a substrate layer, the decorative layer and the top layer, wherein the decorative layer extends between the substrate layer and the top layer, wherein the one or more panels formed also comprise said layers. The decorative layer may be for example a resin-impregnated printed paper, a printed PVC layer, a layer of wood such as a veneer, a print layer largely comprising ink, etc. The decorative layer may for example comprise a wood pattern, a stone pattern, etc. The laser processing may be carried out in such a way that the laser beam does not come into contact with the decorative layer and thus the decorative layer is not marked by the laser beam and the appearance of the decorative layer is not damaged. If the panels are laminate panels, they comprise for example the substrate layer or core, the decorative layer or decor, as well as the top layer based on synthetics. The top layer usually consists of one or more carrier films, for example paper, which are impregnated with resin, for example a melamine resin, such as melamine formaldehyde. In such a case it is usual to make the laminate as a so-called "DPL" (Direct Pressure Laminate), wherein the top layer is pressed directly on the core, or a so-called "HPL" (High Pressure Laminate), wherein the top layer itself is obtained in a pressing operation before said top layer as a whole is applied on the core. Other possibilities for forming said top layer are also possible, for example by using films, the application of a substance that is to be cured, such as a varnish or the like, or in any other way. The decor is usually printed, either directly on the core, provided optionally that there is an intervening primer, or on one or more of the aforementioned carrier films or on the aforementioned film. Moreover, the board may also further comprise a balance layer, which is applied directly or indirectly against the substrate, wherein the balance layer and the top layer extend on either side of the substrate. For a laminate panel the balance layer is for example a resin-impregnated paper, for veneer parquet or parquet the balance layer is for example a veneer or the balance layer comprises wood components, and for floor panels based on PVC the balance layer comprises for example PVC, such as foamed PVC. In a specific embodiment, the top layer comprises one or more wear layers based on synthetics, wherein these one or more wear layers extend on top of the decorative layer. Preferably only the uppermost wear layer is processed by the laser processing and the laser processing is a surface treatment, so that this uppermost wear layer is not processed over the full thickness, being the dimension in the height direction perpendicular to the plane in which the panel extends. Alternatively, during the laser processing over the full thickness of the one or more wear layers, portions of material may be removed, so that the decorative layer is not covered at the level of these removed portions of material. The appearance of the decorative layer is not then affected locally by the top layer. Of course, it is also possible that during the laser processing, portions of material are removed from the decorative layer.

Furthermore, in a preferred embodiment, the decorative layer comprises a pattern, such as a wood pattern or a stone pattern, and the laser processing is carried out on the basis of this pattern. They may be natural patterns such as in the case of veneer parquet floor panels or parquet floor panels that comprise a natural wood pattern. They may also be imitation patterns such as in the case of laminate panels, panels based on vinyl, and the like, which imitate a natural wood pattern or a natural stone pattern, such as a marble pattern. By carrying out the laser processing, being the application of said one or more markings, on the basis of said pattern, this pattern is additionally accentuated and thus the appearance of the panel is optimized, so that the appearance of the panels is perceived as very aesthetic. Thus, the laser processing, being the application of said one or more markings, if the pattern is a wood pattern, may be carried out on the basis of the spring wood present (early wood) and/or the summer wood present (autumn wood or late wood) and/or pores and/or wood imperfections such as knots, brushed parts, etc. If the pattern is a marble pattern, the laser processing may be carried out on the basis of the veins. After carrying out the laser step, we may choose to color the laser-applied markings additionally so as to create a certain look, for example such as a patina or coloring effect. The laser processing may take place in register in the case of imitated patterns or on the basis of a scanned-in pattern for natural patterns. For the latter, for example the pattern may be scanned in by means of cameras prior to the laser processing and then the markings are applied based on the scanned-in pattern. Thus, the laser may be controlled based on what has been scanned in. After scanning, for example indications may also be applied at desired places on the top layer, wherein the laser processing is then carried out at the level of these indications, by detecting these indications.

Even more preferably, the pattern is a wood pattern with one or more pattern elements such as knots and/or cracks and/or fissures and/or pores, and during the laser treatment, at least the top layer at the level of one or more of the one or more pattern elements is exposed to the laser beam of the laser for accentuating these one or more pattern elements. Said one or more markings accentuate pattern elements here. The laser processing may for example color these knots and/or cracks and/or fissures darker and/or may remove material at the level of these knots and/or cracks and/or fissures.

In a specific embodiment, by application of said one or more markings, the laser processing forms zones with different degrees of gloss. The laser processing may also accentuate zones with different degrees of gloss, which were formed during an earlier processing step. In this way, extra dimensions are created, which contributes to an aesthetic appearance. Thus, this may help to create a look of veneer parquet or parquet although no natural wood layer is present.

Also preferably, in this last-mentioned specific embodiment, the zones with different degrees of gloss extend as a function of the pattern.

Furthermore, in a particular embodiment, a relief-creating processing takes place prior to said laser processing, wherein during the relief-creating processing the board is provided with a base structure at least at the level of the top layer, and wherein preferably the laser processing, by application of said one or more markings, further refines and/or accentuates the base structure obtained by the relief-creating processing. The further refining of the relief may comprise the coloring of the relief forming parts and/or the additional removing of material. Thus, an extra matting effect may be obtained by coloring, and/or an extra glossy effect may be obtained by polishing. Relief obtained by conventional methods is limited and often leaves something to be desired. By making use of laser processing, which is carried out after for example forming relief by conventional methods, the relief that is present may be adjusted and/or discolored somewhat, so as to perfect the appearance. The relief-creating processing may for example comprise a pressing operation with a structured press plate, a chemical processing (chemical embossing), and/or a combination of both.

This relief-creating processing step is for example a pressing operation, wherein during the pressing operation the board is pressed with a relief-comprising press plate, so that at the level of the top layer the board comprises a base structure corresponding to the relief, and wherein preferably, by application of said one or more markings, this laser processing further refines the base structure obtained by the pressing operation. A reliefcomprising press plate is also indicated with the term "structured press plate".

Said base structure is preferably based on the pattern. When one panel is formed from the board, this means that the base structure is based on the pattern of this panel. When one or more panels are formed from the board, this means that the relief is preferably based on the pattern of these panels.

In a specific embodiment wherein a said relief-creating processing takes place prior to the laser processing and wherein the panel comprises a said pattern, during the reliefcreating processing, relief-comprising elements, for example such as indentations and/or projections, are formed at one or more places, independently of the pattern, and during the laser processing said one or more markings are applied at the level of none, one or more of said one or more places. The relief-comprising elements are in this case independent of the pattern. This indicates that the relief-comprising elements are preferably not a reflection of the pattern. Said markings are for example applied at the level of one or more of said one or more places. This indicates that during forming of the panels, it is selected at which of said places a marking is or is not applied, thus, it is selected at which of said places there are discolorations of the top layer. After application of a said discoloration, the relief-comprising elements preferably represent pattern elements such as knots and/or cracks and/or fissures, or veins. In other words, we may choose whether or not to represent additional elements of a wood pattern or of a stone pattern. The relief-comprising elements are preferably configured so that when it is chosen not to apply any markings at certain said places, the relief-comprising elements have little effect on the look of the panel. Here, the pattern of the decorative layer thus forms the basic pattern and we may choose whether or not to add additional elements to this basic pattern. Thus, panels may be obtained that have a different look, but that each have the same basic pattern. In the case of a wood pattern, we may thus for example have different panels with the same basic wood pattern, but wherein one panel for example comprises an extra knot and the other panel for example comprises an extra crack, and so on. In this way, it is possible to reduce the repetition of patterns in so-called imitation patterns, for example for laminate panels or panels based on vinyl, and there are fewer repeats. The more said places are present per panel, the less the repetition. It is clear that in this case application of markings is not limited to said laser processing and/or also that this is not limited to panels. The foregoing is thus also applicable to the aforementioned second variant embodiment, and also to the aforementioned third variant embodiment of the invention, wherein the laser processing is then replaced with some other processing wherein markings are applied that comprise discolorations of the top layer.

Preferably, the board comprises at least three layers, being a substrate layer, said decorative layer and said top layer, wherein the decorative layer extends between the substrate layer and the top layer, wherein the one or more panels formed also comprise said layers.

Specifically, for example, the substrate layer comprises a wood-based substrate, such as a wood fiberboard or a chipboard, and the decorative layer and the top layer comprise a resin-impregnated paper. The resin is for example a thermosetting resin such as a melamine resin, a melamine formaldehyde resin, a urea formaldehyde resin, etc. The decorative layer comprises for example a decorative paper and the top layer comprises for example one or more papers, which are each impregnated with a resin. Preferably the top layer comprises thin transparent paper, so that the decorative layer is easily visible. The resin of the top layer may further comprise wear-resistant particles, such as corundum and aluminum oxide. These may then for example be called laminate panels. Preferably, during the laser processing, no processing of said paper of the top layer takes place and only the resin is processed.

In another specific embodiment, the decorative layer comprises a layer of wood and the top layer comprises one or more varnish coats. It is called a veneer if the layer of wood is thinner than 2.5 mm. It is evident that in another embodiment the decorative layer may also comprise a layer of wood of more than 2.5 mm, which is then called parquet if the panel is a floor panel. Also preferably, the top layer comprises two or more varnish coats. These varnish coats preferably comprise a resin such as an acrylic resin, an alkyd resin or a polyurethane resin. It was found, surprisingly, that by means of a UV laser, markings can be applied in the varnish coat, with which the look of a panel, for example a veneer parquet floor panel or a parquet floor panel, is optimized, while the one or more varnish coats still impart the necessary wear-resistant and other resistant properties to the panel.

Also in a specific embodiment, the decorative layer is a PVC-based layer. This is for example the case with floor panels based on vinyl. The top layer may then comprise an uppermost varnish coat, which for example cures under the effect of UV light, and optionally one or more additional PVC layers. The top layer may also comprise only one or more PVC layers. It was found, surprisingly, that by means of a UV laser, markings can be applied in this top layer, so as to optimize the appearance of the panel. The top layer may in this case for example comprise several layers, wherein a said layer is a decorative layer, which may or may not extend centrally in the top layer.

The substrate layer may for example comprise a mineral-based substrate, such as a gypsum-based or cement-based substrate. Thus, the substrate may be a gypsumboard or a gypsum fiberboard. The substrate may for example be a fiber cement board or a magnesium oxide board. The substrate may also be based on a geopolymer.

In a particular embodiment, during the laser processing, use is made of two or more laser beams from for example the UV spectrum. Thus, use may be made of a laser with one laser source with a "beam splitter", which splits the basic laser beam emitted by the laser source into two or more laser beams. Use may also be made of several laser sources. The laser source may for example be positioned stationary, wherein other components of the laser are mounted to be mobile and/or adjustable so as to be able to apply the desired markings.

The wavelength of a said laser beam is preferably between 150 and 400 nm, for example between 300 and 400 nm, or for example between 330 and 370 nm. Thus, the wavelength may for example be 153 nm or 355 nm. When there are two or more laser beams, these may emit light with some other wavelength. It is thus easy to apply various types of markings, for example markings with some other hue. The wavelength of a said laser beam may also be between 500 and 560 nm, even more preferably between 520 and 540 nm.

In a much preferred embodiment, a said processing step is the sawing of the board into one or more base panels, after which one or more of these one or more base panels are submitted to said laser processing, wherein for this, preferably a laser system comprising the laser is mounted at a fixed position, and these base panels are moved along this laser system. The laser system is in this case placed at a fixed position. Preferably the laser source occupies a fixed position in this laser system and for example other components are mounted movably so that the desired markings can be applied. In a configuration such as this, the base panels are moved along the laser beam.

In a specific embodiment, the top layer comprises additives, wherein on exposure to the laser beam of the laser, these additives cause discolorations of the top layer. In this way, the desired discoloration may be obtained by means of the laser processing. These additives may, for example, under the effect of the laser beam, undergo a photochemical change and/or be heated strongly, and thus provide a color change in the top layer. This color change may for example be the result of foaming of the plastic. The additives themselves may also discolor under the effect of the laser beam.

By carrying out this method as described above, it may optionally additionally be achieved that the panels are easier to clean: "easy to clean". The invention also relates to a panel, such as a floor panel, manufactured by the aforementioned method.

The invention also relates to a panel, such as a floor panel, of the type with at least two layers and of which a said layer is a top layer, wherein at least the top layer comprises one or more markings which for example form discolorations of the top layer and wherein preferably the markings are markings applied by laser, such as markings applied by UV laser, and wherein preferably the top layer is based on synthetics. In a specific embodiment the markings may be applied by means of a green laser. This relates to a panel that may be manufactured by the aforementioned method according to the invention. All advantages and preferred embodiments described in the method are thus applicable to this panel. "Markings applied by laser" means markings that are brought about at least partially by means of a laser. Thus, this does not exclude that the markings are additionally applied by means of other techniques. Thus, the markings may be indentations, wherein the indentations are brought about by a combination of pressing with a structured press plate or some other relief-forming technique such as "chemical embossing", and a laser, such as a UV laser.

Preferably, the one or more markings comprise indentations, which open out at least at the top and preferably only at the top of the panel and wherein further preferably, seen along a plane that extends according to the panel, the one or more markings are each largely surrounded by remaining regions of the top layer. These markings may be superficial and for example have a dimension, in a direction perpendicular to the plane in which the panel extends, of at most 20 micrometers, preferably at most 10 micrometers.

Also preferably, the panel comprises a decorative layer that may or may not form part of the top layer, wherein the decorative layer comprises a pattern, such as a wood pattern or stone pattern. The stone pattern is for example a marble pattern.

In a preferred embodiment, the top layer comprises one or more wear layers based on synthetics, wherein these one or more wear layers extend on top of the decorative layer and comprise said indentations. Here, the indentations then preferably only extend at the level of the one or more wear layers and are not present in the decorative layer. These indentations are preferably indentations applied by UV laser, but these indentations may also be applied by other techniques, for example with other types of lasers and/or by means of structured press plates and/or chemical embossing and/or a combination of various techniques.

Also preferably, the pattern is a wood pattern with one or more pattern elements such as knots and/or cracks and/or fissures and/or pores, and these one or more pattern elements are accentuated by means of said markings. Thus, the top layer is for example colored darker by the markings at the level of these knots and/or cracks and/or fissures and/or pores.

In a much preferred embodiment, the top layer comprises a relief, wherein zones of this relief are obtained by the combination of a pressing operation with a relief-comprising press plate and/or another relief supplying technique such as "chemical embossing", and the one or more laser-applied markings. The pressing operation then for example provides a basic relief, while the laser-applied markings further refine and/or color the basic relief.

These panels may have all kinds of configurations. The following is a nonexhaustive list of possible characteristic features of the panels that may be combined with one another so long as they are not incompatible with each other:

- the panel comprises at least 3 layers, being a substrate layer, said decorative layer and said top layer, wherein the decorative layer extends between the substrate layer and the top layer.

- the panel comprises a wood-based substrate, such as a wood fiberboard or a chipboard;

- the decorative layer comprises a resin-impregnated paper;

- the top layer comprises a resin-impregnated paper;

- the decorative layer comprises a layer of wood, such as a veneer;

- the top layer comprises one or more varnish coats;

- the decorative layer is a PVC-based layer; - the panel comprises a mineral-based substrate, such as a gypsum-based, cement-based or geopolymer-based substrate.

In a specific embodiment, the panel comprises pigments fixed in the top layer. These pigments fixed in the top layer preferably extend at the level of the one or more markings, wherein the pigments are fixed in the top layer by means of a laser, such as a UV laser. These markings then for example form part of laser-applied markings. Preferably, these pigments extend superficially in the top layer, for example at a distance of at most 20 micrometers, preferably at most 10 micrometers from the top of the panel. It is even possible that pigments contribute to formation of the upper side of the panel. However, other techniques are also possible for fixing pigments in the top layer, for example by means of heat, by pressing, etc.

For the purpose of better illustrating the characteristic features of the invention, some preferred embodiments are described hereunder, as examples without any limiting character, referring to the appended drawings, in which:

- Fig. 7 is a perspective view of a panel according to the invention comprising a wood pattern, manufactured by a method according to the invention;

- Fig. 2 is a perspective view of a panel according to the invention comprising a stone pattern, manufactured by a method according to the invention;

- Fig. 3 is a detail of section F3 of the panel shown in Fig. 1;

- Fig. 4 i a. detail of section F4 of the panel shown in Fig. 1;

- Fig. 5 is a detail of section F5 of the panel shown in Fig. 1.

The figures show two floor panels 1 according to the invention, which have been manufactured by a method according to the invention. The floor panel 1 shown in Fig. 1 comprises a wood pattern. The floor panel 1 shown in Fig. 2 comprises a stone pattern.

These floor panels 1 comprise, viewed from bottom to top, optionally a balance layer, a core layer, a decorative layer and a top layer 2. These floor panels 1 are for example laminate panels, wherein the top layer 2 comprises a resin-impregnated paper, being an "overlay" or "wear layer", the decorative layer is a resin-impregnated printed paper, wherein this decorative layer comprises said wood pattern or stone pattern, the core layer comprises a wood fiberboard and the balance layer is a resin-impregnated paper. The floor panels 1 may also be based on PVC, wherein the core layer and the balance layer comprise flexible and more flexible PVC, respectively, the decorative layer is a printed PVC layer with the wood pattern or the stone pattern and the top layer 2 comprises a PVC wear layer and a UV varnish coat, which extends according to the panel 1. Other constructions of the floor panels 1 are also possible. Thus, the core layer may be mineralbased, or in the case of the floor panel 1 shown in Fig. 1, the floor panel 1 may be a parquet or a veneer parquet, wherein the decorative layer is a layer of wood, the top layer 2 comprises one or more varnish coats and the core layer comprises a wood fiberboard or strips. In all possible embodiments, the top layer 2 is always based on synthetics.

To manufacture these panels 1, the following operations are carried out. First a board is formed comprising the aforesaid layers. This board is then cut into several base panels. Several processing steps are then carried out on these base panels to produce said floor panels 1. The processing steps are for example the forming of coupling elements so that these panels 1 are easily couplable together.

One of these processing steps is a laser processing, wherein the top layer 2 is exposed to one or more laser beams of a UV laser or of a so-called green laser, which emits green visible light. The UV laser for example emits light with a wavelength between 330 and 370 nm and said green laser for example emits light with a wavelength between 495 nm and 570 nm. Here, only the top layer 2 is exposed to said one or more laser beams. Preferably, if the top layer 2 consists of several layers, only the uppermost layer of the top layer 2 is exposed to the one or more laser beams. The result is one or more markings 3, which form discolorations of the top layer 2, wherein these markings 3 extend superficially. These markings 3 may or may not additionally form indentations with heights of at most 20 micrometers, viewed in a height direction that extends perpendicularly to the plane in which the floor panels 1 extend.

These markings 3 may assume all kinds of shapes. Thus, these markings 3 may represent words, logos, illustrations and the like. Fig. 3 shows a marking 3 that illustrates a logo. These markings 3 may, in the case of a wood pattern, accentuate knots and/or cracks and/or fissures present in the wood pattern of the decorative layer, because the markings 3 provide a local darker discoloration of the top layer 2. This can for example be seen easily in Figs. 4 and 5. The dark lines of the stone pattern may also be further accentuated by markings 3 because the markings 3 form dark discolorations of the top layer 2. The appearance of the stone pattern in Fig. 2 is thus optimized.

Very preferably, said laser processing is used in order to improve the appearance of wood patterns. Thus, prior to the laser processing, and preferably also prior to cutting up into the base panels, a pressing operation may be carried out to form the boards. The boards may for example be pressed by means of a structured press plate, being a press plate provided with a relief. In this way, a structured board is obtained, wherein at least the top layer 2 is provided with a relief. Alternatively or additionally, the relief of the board may also be obtained chemically by so-called "chemical embossing". Preferably, use is made of "embossing in register" so that the relief is contiguous with the wood pattern. The board and thus also the base panels are then already provided with a basic relief, which optimizes the appearance. The appearance is optimized even further by the laser processing. This may for example be because the markings 3 provide local desired colorations, for example at the level of indentations of the basic relief and/or by further refining the basic relief, for example by removing material locally and/or deforming the basic relief locally.

Whether or not additionally, pigments may be spread on top of the top layer 2, prior to or during the exposing of at least the top layer 2 to said one or more laser beams, so that the pigments that come into contact with a said laser beam are fixed in the panel 1. After the laser processing, the remaining pigments that were not fixed in the panel 1 are removed. In this way, the markings 3 can acquire the desired color.