Method and system for controlled application of primer liquid and resin upon a substrate for roll-to-plate nanoimprinting

Abstract

The invention relates to a method for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting, comprising the steps of applying at least one primer liquid to at least one substrate via spraying and subsequently applying at least one resin to the at least one substrate via droplet deposition, wherein at least one primer liquid is applied to the at least one substrate in a first predetermined pattern and wherein at least one resin is applied to the at least one substrate in a second predetermined pattern, wherein at least part of the second predetermined pattern overlaps with the first predetermined pattern.

Description

[0001] Method and system for controlled application of primer liquid and resin upon a substrate for roll-to-plate nanoimprinting

[0002] The invention relates to a method for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting. The invention further relates to a system for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting.

[0003] Primer liquids are typically used to promote adhesion between a substrate (e.g. glass) and resin layers which are subsequently provided with a (nano)imprint. Usually, primer liquids are applied in a super thin layer over the entire surface of a substrate with a constant thickness of 0.1 nm up to a few micrometres. Traditional methods for applying primer liquid are for example spin coating and doctor blade coating. However, spin coating is challenging to apply to the typically large (>300 mm) and non-circular substrates that are used in roll-to-plate nanoimprinting, whereas doctor blade coating may fail to produce primer layers that are thin enough. Furthermore both coating techniques do not easily allow for localized control over the liquid deposition. Alternatively, spray coating can be a preferred technique. This technique enables that the entire surface of the substrate which is to be imprinted can be covered with primer liquid, and the thickness of primer liquid is aimed to be more or less constant over the surface. Subsequently, an imprinting resin is applied to the primed substrate, whereafter the substrate can be imprinted. A drawback of the present techniques is that they require typically use relatively large quantities of primer liquid and resin to ensure that the final product can be made. This is costly due to the use of excess of materials and limits the controllability of the process.

[0004] Hence, it is a goal of the invention to provide an optimized method and system for application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting, or at least to provide an alternative to the known methods and systems.

[0005] The invention provides thereto a method for controlled application of primer liquid and resin onto a substrate, preferably for nanoimprinting, in particular for roll-to- plate nanoimprinting, comprising the steps of: - applying at least one primer liquid to at least one substrate via spraying, wherein at least one primer liquid has a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s ; and subsequently

[0006] - optionally applying at least one resin to the at least one substrate preferably via droplet deposition, wherein at least one resin has a viscosity in the range of 0.1 to 50,000 mPa-s, in particular 1 to 2,000 mPa-s, more in particular 5 to 1 ,000 mPa-s, even more in particular 10 to 200 mPa-s; wherein at least one primer liquid is applied to the at least one substrate in a first predetermined pattern and wherein at least one resin is preferably applied to the at least one substrate in a second predetermined pattern, wherein at least part of the second predetermined pattern overlaps with the first predetermined pattern.

[0007] The method according to the present invention has several benefits over conventional methods for applying primer liquid and resin onto a substrate for roll- to-plate nanoimprinting processes. The combination of applying at least one primer liquid to at least one substrate via spraying in a first predetermined pattern and applying at least one resin to the at least one substrate via droplet deposition in a second predetermined pattern, wherein at least part of the second predetermined pattern overlaps with the first predetermined pattern, results in that both the primer liquid and the resin can be applied in a precise and effective manner. The method according to the invention enables that specific depicted areas of the substrate which is to be imprinted can be primed and subsequently coated with resin. The amount of primer liquid and / or resin applied can in this way be optimized and in particular reduced by applying the substance(s) in a predetermined pattern. Conventional methods typically apply an excess of primer liquid which covers the entire substrate whereas the method according to the present invention provides for the supply of primer liquid merely at predetermined areas. The method according to the present invention enables parts of the substrate to stay free of primer liquid. This is for example desired for areas whereof it is not desired that resin adheres to the substrate, and in particular where the substrate should be kept naked. This could for example be the case in the input pupil of a waveguide of an augmented reality (AR) device. Another example wherefore this would be beneficial is the application of primer liquid to an assembly of a relatively large substrate which comprises multiple small elements that individually need to be supplied with primer liquid. This would allow for upscaling production, as multiple small products may be comprised in one large substrate. The areas between these elements typically should not be provided with primer liquid as this could negatively affect the overall product. Yet another example would be a product that would require locally a higher or lower amount of primer liquid for aesthetic and / or optical reasons.

[0008] The application of the at least one primer liquid via spraying is beneficial in case a primer liquid having a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s is applied. The viscosity of the primer liquid is relatively high wherefore via spraying of the primer liquid in a predetermined pattern enables that the primer liquid can be applied to the surface in a controlled amount at predetermined areas. Spraying is therefore preferred over application techniques such as spin coating or doctor blade coating.

[0009] The application of the at least one resin via droplet deposition is beneficial in case the resin has a viscosity in the range 0.1 to 50,000 mPa-s, in particular 1 to 1 ,000 mPa-s, more in particular 10 to 200 mPa-s. This viscosity is sufficiently low to enable droplet formation and specific and controlled positioning thereof. When it is referred to droplet deposition, the application of droplets of at least one resin to the substrate is meant. When it is referred to predetermined pattern a predetermined template could also be meant. In an alternative embodiment, it is conceivable that at least one resin is applied to the at least one substrate via a coating technique, in particular slot die coating, doctor blade coating, spin coating and / or combinations thereof. It is also imaginable that droplet deposition and a coating technique are combined.

[0010] Preferably, at least part of the first predetermined pattern and at least part of the second predetermined pattern mutually differ. In particular, the first predetermined pattern and the second predetermined pattern are different patterns. It is imaginable that at least part of the first predetermined pattern and at least part of the second predetermined pattern are mutually similar or equal. In particular, the first predetermined pattern and the second predetermined pattern may be similar or equal patterns. The second predetermined pattern and the first predetermined pattern may entirely overlap. In particular, the second predetermined pattern may entirely overlap the first predetermined pattern. This embodiment contributes to controlling desired areas where the resin adheres to the substrate, and in particular where the substrate should be kept naked.

[0011] At least one substrate applied in the method according to the present invention is in particular a substrate which is to be imprinted. At least one substrate is preferably a plate shaped substrate or a plate-like substrate configured and / or suitable for roll- to-plate imprinting. It is imaginable that at least one substrate which is to be imprinted comprises multiple sections which are to be imprinted. Hence, it is imaginable that at least one primer is applied to each section which is to be imprinted. It is imaginable that the first predetermined pattern substantially equals the configuration of the sections which are to be imprinted. The method according to the present invention also enables that multiple substrates can be provided with primer liquid subsequently or even substantially simultaneously by the same device or system. It is for example imaginable that multiple substrates are provided upon a carrier. The method enables for efficient and controlled provision of primer liquid and resin to multiple substrates substantially simultaneously or at least sequentially.

[0012] The method according to the invention could also be referred to as a method for imprinting. At least one primer liquid could also be referred to as primer. Within the context of the present invention, primer liquid is configured to increase and / or promote adhesion between the substrate which is to be imprinted and the resin applied for imprinting.

[0013] At least one primer liquid is in particular applied to a predetermined part of the at least one substrate such that the area defined by primer liquid is smaller than the total area of the at least one substrate. In this way, part of the surface of the at least one substrate will not be covered with primer liquid. It is for example possible that the predetermined part of the at least one substrate which is covered by primer liquid is at least 10% smaller than the total area of the at least one substrate, preferably at least 20% smaller, more preferably at least 30% smaller. Applying the primer liquid only at a predetermined part of the substrate results in a significant reduction of primer liquid which is to be applied compared to conventional methods wherein the entire surface of the substrate is fully covered with primer liquid. As indicated above, for several specific applications it is undesired to fully cover the substrate with primer liquid. By applying the primer liquid in a predetermined spray pattern, the use of a stencil could be omitted. The latter would still result in the application of an excess of primer liquid and would be more prone to deficiencies due to aligning difficulties and / or leakage of liquid.

[0014] A primer area may be defined by the at least one primer liquid applied to at least one substrate. A resin area may be defined by the at least one resin applied to the at least one substrate. Preferably, the primer area is larger than the resin area. The primer area is in particular larger than the resin area at least prior to performing an optional subsequent imprinting step of at least part of the resin. This embodiment is beneficial as it provides a sufficient amount of primer liquid on the substrate for coating said primed substrate with resin. This embodiment therewith further contributes to optimizing the amount of primer liquid and / or resin applied.

[0015] When it is referred to spraying within the context of the present invention, it could also be said that the primer liquid is applied via a spray technique and / or via at least one spray. At least one primer liquid is typically applied via at least one spray valve. The use of at least one spray valve can positively contribute to the controlled application of primer liquid onto the substrate which is to be imprinted. When it is referred to a spray valve also a spray nozzle could be meant or at least one spray valve could comprise at least one spray nozzle. At least one primer liquid is preferably applied via multiple spray valves. The use of multiple spray valves may enable the provision of relatively large quantities of primer liquid in an efficient and effective manner.

[0016] It is possible that the method involves that at least part of the first predetermined pattern has a non-homogeneous thickness distribution of primer liquid. Hence, the at least one primer liquid can be applied such that at least part of the first predetermined pattern has a non-homogeneous thickness distribution of primer liquid. At least part of the first predetermined pattern can for example have a variable layer thickness. It is imaginable that the at least one substrate is provided with primer liquid such that parts thereof have locally a higher or lower amount of primer liquid compared to further parts of the substrate. It is for example imaginable that at least part of at least one primer liquid is applied to the at least one substrate in a variable layer thickness. This could for example be achieved by spraying parts of the substrate multiple times with primer liquid. Hence, it is imaginable that part of the substrate is sprayed a single time with primer liquid while a further part of the substrate is sprayed at least two times, or multiple times, with primer liquid. It is also possible that the method and / or system is configured to provide different quantities of primer liquid during the application thereof in particular such that a variable layer thickness of primer liquid is achieved. This is for example possible by adjusting the amount of primer liquid issued by at least one spray valve and preferably each individual spray valve. It can for example be beneficial to apply an increased layer thickness of primer liquid at areas which surround the area which is to be imprinted. Such areas could for example be resin outflow areas, outside an active area, where it is to be ensured that an excess of resin sticks to the substrate and not to the stamp applied for imprinting, as this could filth the system. So in the outflow area(s), a thicker primer liquid layer might be desired than in the active area, where typically the thickness of primer liquid is ideally kept at a minimum.

[0017] It is possible that at least part of at least one primer liquid is applied to the at least one substrate in a substantially non-uniform layer thickness and / or that at least part of at least one primer liquid is applied to the at least one substrate in a substantially uniform layer thickness. Preferably, at least part of at least one primer liquid is applied to the at least one substrate in a controlled and / or predetermined thickness. It is possible that at least part of at least one primer liquid is applied to the at least one substrate such that a gradient in layer thickness exists. The homogeneity of the applied primer liquid layer is important, in particular the thickness and distribution of primer liquid, as well as its optical properties like refractive index to obtain a consistent and homogeneous final imprinted product. This is in particular of relevance for products that require relatively thin resin layers, typically of 1 pm or lower. Hence, control of the layer thickness of the primer liquid is of relevance.

[0018] At least one primer liquid is applied to the substrate which is to be imprinted via at least one spray valve and preferably via multiple spray valves. In a possible embodiment, the spray valve height of at least one spray valve, the velocity of displacement of at least one spray valve, the orientation of at least one spray valve and / or the displacement pattern of at least one spray valve is controlled and / or adjusted during application of at least one primer liquid to the at least one substrate. The spray valve height of at least one spray valve, the velocity of displacement of at least one spray valve, the orientation of at least one spray valve and / or the displacement pattern of at least one spray valve can preferably be controlled and / or adjusted during application of at least one primer liquid to the at least one substrate such that at least one primer liquid is applied to the at least one substrate in a first predetermined pattern and / or in a substantially non-uniform layer thickness. It is beneficial if at least one spray valve parameter can be controlled and / or adjusted, as this results in large flexibility of possible primer liquid patterns and layer thickness which can be obtained. Increasing the velocity of displacement of at least one spray valve could for example result in a decreased layer thickness. Also increasing the spray valve height of at least one spray valve, or increasing the distance between the substrate which is to be imprinted and at least one valve, could result in a decreased layer thickness. Adjusting the displacement pattern of at least one spray valve could affect both the layer thickness and the pattern of the applied primer liquid. Adjusting the orientation of at least one spray valve, and preferably of multiple spray valves can contribute to the controllability of the sprayed pattern, in particular the first predetermined pattern. It is also imaginable that the orientation of at least part of the spray valves, and preferably the orientation of each spray valve is individually adjustable.

[0019] At least part of at least one resin is preferably applied via a droplet dispense technique. At least part of at least one resin is typically applied via at least one jet valve or piezo actuated valve. Alternatively at least one inkjet nozzle could be applied In this way, the resin can be applied in a controlled and accurate manner. Possibly, at least part of at least one resin is applied to the at least one substrate in an interrupted pattern. It is for example possible that at least part of at least one resin is applied in a non-continuous pattern. It is for example possible that at least one resin is applied to the substrate via droplet deposition such that dots, or droplets, of resin are obtained upon the substrate. It is also conceivable that the resin is applied via droplet deposition such that a layer of resin is applied to the substrate.

[0020] At least part of the second predetermined pattern preferably overlaps with the first predetermined pattern. In this way, the resin can be applied to at least the areas where primer liquid has been applied. It is for example imaginable that the first predetermined pattern substantially equals the second predetermined pattern. The second predetermined pattern may thereby be defined by a non-uniform and / or dotted layer. The resin is preferably applied such that imprinting of the resin, in particular via rol l-to-plate imprinting with a flexible stamp, results in substantially full coverage of the first predetermined pattern with resin. It is possible that upon application, at least part of the resin defining the second predetermined pattern is shifted with respect to first predetermined pattern. Possibly, at least part of the droplets of resin is applied in a repeated configuration. Hence, it is possible that at least part of the droplets, or dots, of resin is arranged in a line and / or shape. Possibly, at least part of the droplets, and preferably substantially all droplets of resin have substantially the same volume. However, it is also imaginable that the volume of resin applied deviates for example based on the second predetermined pattern.

[0021] In a possible embodiment, the first pattern comprises at least two pattern sections which are at a distance from each other. At least one pattern section may have a different layer thickness and / or shape as a further pattern section. It is also imaginable that at least one pattern section has a substantially equal layer thickness and / or shape as a further pattern section. In yet another possible embodiment, the first pattern comprises at least two pattern sections which are in line with each other, wherein at least two section have a different layer thickness.

[0022] At least one primer liquid preferably has a viscosity in the range of 0 to 100,000 mPa-s, more preferably in the range of 0 to 100 mPa-s, most preferably in the range of 0.1 to 10 mPa-s. Possibly, at least one primer liquid has a viscosity in the range of 0.3 to 8 mPa-s, preferably in the range of 0.5 to 5 mPa-s, more preferably in the range of 1 to 3 mPa-s. However, it is also conceivable that at least one primer liquid has a viscosity in the range of 0.5 to 3 mPa-s. At least one primer liquid can for example have a viscosity below 10mPa-s, preferably below 5 mPa-s, more preferably below 2.5 mPa-s.

[0023] At least one resin preferably has a viscosity in the range 0.1 to 50,000 mPa-s, in particular 1 to 1 ,000 mPa-s, more in particular 10 to 200 mPa-s. However, it is also conceivable that at least one resin has a viscosity in the range of range of 0.2 to 2,500 mPa-s or possibly in the range of 10 to 100 mPa-s or in the range of 5 to 2,000 mPa-s. In a possible embodiment, at least one resin has a viscosity in the range of 15 to 150 mPa-s, preferably in the range of 20 to 100 mPa-s, more preferably in the range of 25 to 75 mPa-s.

[0024] The method according to the invention may also comprise the step of (nano)imprinting at least part of the resin. Imprinting is preferably nanoimprinting performed via roll-to-plate imprinting using a substantially flexible stamp. The imprinting is for example configured to provide an imprinted texture. Typically the substantially flexible stamp comprises a textured area. The textured can for example comprises a texture with dimension typically in the range from 500 micrometer down to 25 nanometer. The texture can for example comprise a repeated pattern and / or the texture may be configured for optimizing the optical characteristics of the imprinted (cured) resin or the imprinted product. At least part of the texture could for example be applied for optical purposes. The flexible stamp is in particular configured for nano-imprint lithography transfer processes. It is also imaginable that at least one flexible stamp is attached to at least one roller and / or that at least one flexible stamp is provided over at least one roller. The roller can for example be at least partially covered with at least one flexible stamp.

[0025] At least part of the first predetermined pattern and at least part of the second predetermined pattern may be adjacent to each other and / or at a distance from each other. A transit region may be present at least at a part of at least one side edge of the first predetermined pattern, wherein the transition region may be defined as a region wherein a part of the second predetermined pattern adjacent to a part of the first predetermined pattern transits into an overlapping part of the first predetermined pattern and the second predetermined pattern. A part of the first predetermined pattern and a part of the second predetermined pattern may be arranged adjacent to each other and / or at a distance from each other. Hence, part of the first predetermined pattern and part of the second predetermined pattern may not overlap. In particular, at least part of the transit region forms a leading side edge for an optional imprinting step. A leading side edge can be defined as a starting position for imprinting. During an optional imprinting step, at least part of the resin is imprinted in an imprinting direction starting from the leading side edge and running up to a trailing side edge of the first predetermined pattern. The trailing side edge is preferably free from a transit region. Optionally, the trailing side edge is free from a second predetermined pattern at least prior to the imprinting step. This embodiment is beneficial as during imprinting the resin follows the imprinting direction, in particular from the leading side edge to the trailing side edge. As a consequence, a resin layer is moved and / or spread over the primer liquid during imprinting along its imprinting direction. This contributes an optimized method for applying resin onto a substrate.

[0026] The invention also relates to a method for controlled application of primer liquid to a substrate prior to roll-to-plate nanoimprinting, comprising applying (at least one layer of) at least one primer liquid to at least one substrate via at least one spray valve, wherein at least one primer liquid has a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s wherein at least one layer of at least one primer liquid is applied to a first predetermined area of the at least one substrate and / or with a predetermined (variable) layer thickness. Any of the described embodiments of applying primer liquid could apply to the above method.

[0027] The invention further relates to a system for controlled application of primer liquid and resin onto a substrate in particular for roll-to-plate nanoimprinting preferably via the method according to any of the previous claims, comprising:

[0028] - at least one (displaceable) primer liquid applicator for applying at least one primer liquid to at least one substrate which is to be imprinted, said primer liquid applicator comprising at least one spray valve configured for spraying at least one primer liquid having a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s;

[0029] - preferably at least one (displaceable) resin applicator for applying at least one resin with a viscosity in the range of 0 to 50,000 mPa-s, in particular 1 to 2,000 mPa-s, more in particular 5 to 1 ,000 mPa-s, even more in particular 10 to 200 mPa-s, to the at least one substrate preferably via droplet deposition; and

[0030] - at least one control unit which is configured to control and / or adjust at least one parameter, and preferably at least two parameters of the at least one primer liquid applicator, in particular during the application of primer liquid onto the at least one substrate, wherein the parameter(s) is / are chosen from the group of: the spray valve height of at least one spray valve, primer liquid flow rate from at least one spray valve, the velocity of displacement of the at least one primer liquid applicator, the orientation of at least one spray valve and / or of at least one spray valve, the displacement pattern of the at least one primer liquid applicator and / or of at least one spray valve.

[0031] The invention also relates to a system for controlled application of primer liquid upon a substrate for roll-to-plate nanoimprinting. The system according to the present invention enables that at least one primer liquid can be applied to the at least one substrate in a first predetermined pattern and with a predetermined layer thickness. Additionally the method may enable that at least one resin is applied to the at least one substrate via droplet deposition in a second predetermined pattern, in particular such that at least part of the second predetermined pattern overlaps with the first predetermined pattern. At least one control unit is preferably configured to substantially simultaneously control and / or adjust at least one parameter, and preferably at least two parameters, and more preferably at least three parameters of the at least one primer liquid applicator during the application of primer onto the substrate.

[0032] It is also imaginable that at least one (displaceable) resin applicator is configured for applying at least one resin to the at least one substrate via coating, in particular slot die coating, doctor blade coating, spin coating and / or combinations thereof. It is also imaginable that droplet deposition and a coating technique are combined.

[0033] The at least one control unit is preferably configured to control and / or adjust at least one parameter during displacement of the at least one primer liquid applicator and / or at least one spray valve thereof. In this way, the a first predetermined pattern and / or the desired layer thickness can be obtained effectively and in a controlled manner. The at least one system in particular provides for a start / stop configuration, wherein the application of at least one primer liquid and / or at least one onto the substrate can be substantially fully controlled. The specific parameters which can be tuned by the at least one control unit have an individual and / or synergetic effect on the pattern and layer thickness of the applied primer liquid. Increasing the spray valve height of at least one spray valve may reduce the layer thickness whereas increasing the primer liquid flow rate from at least one spray valve will increase the layer thickness. Both parameters may further affect the spray pattern which is obtained. The velocity of displacement and the displacement pattern of the at least one primer liquid applicator and / or of at least one spray valve will typically affect the pattern and the layer thickness. The system and method according to the present invention enable the application of primer liquid with a variable thickness to a substrate.

[0034] In a possible embodiment, at least one primer liquid applicator comprises at least one liquid channel for supplying at least one primer liquid to at least one spray valve. The control unit may be configured to control and / or adjust the dimension of at least one opening in at least one liquid channel that supplies primer liquid to the spray valve. It is also imaginable that the control unit is configured to control and / or adjust the dimension of at least one nozzle opening of at least one spray valve. In practise, a larger liquid channel opening and / or nozzle opening will result in a higher primer liquid flow rate. It is for example possible that at least one opening is controlled via a stroke. The stroke setting determines the size of the opening in the liquid channel that supplies primer liquid to the (nozzle) opening.

[0035] It is also imaginable that at least one control unit is configured to control at least one parameter of at least one spray valve, wherein at least one parameter is chosen from the group of: the fan air pressure (in bar), the primer liquid flow rate (in mL / s), the spray valve stroke setting, the liquid pressure (in bar) and / or the spray shape. The spray shape is relevant for the shape of the beam in particular when it contacts the surface, and thus for the area which will be covered. It is also imaginable that at least one control unit is configured to control and / or adjust the sprayed liquid volume, sprayed liquid volume distribution and / or the spray pattern of at least one spray valve. It is for example possible that the system, and in particular at least one primer liquid applicator, comprises at least two spray valves, wherein the spray bundle of a first spray valve provides a larger spray bundle than a second spray valve and / or wherein the spray shape of a first spray valve differs from the spray shape of a second spray valve.

[0036] It is imaginable that the system, and in particular at least one primer liquid applicator comprises multiple spray valves. It is possible that at least two spray valves are positioned substantially parallel to each other. It is also possible that the system, and in particular at least one primer liquid applicator comprises multiple spray valves which spray valves are arranged in spatial configuration. Each spray valve is preferably configured for spraying at least one primer liquid having a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s. It is possible that at least one control unit is configured to control the mutual distance between at least two adjacent spray valves, and preferably between multiple adjacent spray valves. Adjusting the mutual distance between at least two spray valves enables that the primer liquid flow rate distribution can be optimized. It is for example possible that at least two adjacent spray valves are positioned such that primer liquid is applied to the substrate such that at least part of the spray bundles overlap. In this way, a variable layer thickness of primer liquid can be created in a relatively simple and controlled manner. It is also imaginable that at least two spray valves are positioned such that primer liquid is substantially homogeneously and / or uniformly applied to the substrate.

[0037] In a possible embodiment wherein at least one control unit is configured to control at least one parameter of the at least one resin applicator during the application of resin onto the at least one substrate, wherein the parameters are chosen from the group of: the height of the at least one resin applicator, the velocity of displacement of the at least one applicator, the displacement pattern of the at least one resin applicator, the resin pressure supply, and / or the resin flow rate. The specific parameters which can be tuned by the at least one control unit have an individual and / or synergetic effect on the pattern and layer thickness of the applied resin. It is for example possible that at least one parameter is adjusted based upon at least one output characteristic.

[0038] In a possible embodiment, the system, and in particular the primer liquid applicator, more in particular at least one spray valve, comprises at least one liquid channel for supplying at least one primer liquid to at least one spray valve. At least one control unit may be configured to control and / or adjust the dimension of the opening in at least one liquid channel that supplies primer liquid to at least one spray valve. It is also imaginable that at least one primer liquid applicator, and in particular at least one spray valve thereof, is configured for applying at least one primer liquid with a non-homogeneous thickness distribution over the surface over at least one substrate which is to be imprinted. This is for example possible by providing an overlapping spray configuration for at least two spray valves of at least one primer liquid applicator. It is also possible that by adjusting the dimensions of the channel, the spray pattern of at least one spray valve, and preferably of multiple spray valves, is controlled. It is also possible that at least two (adjacent) spray valves are positioned at a different height with respect to the surface which is to be imprinted. It is also imaginable that a non-homogeneous output, such as a variable layer thickness, is obtained by individual control and / or adjustments of at least two spray valves of the primer liquid applicator.

[0039] The system may comprise at least one carrier for carrying at least one substrate which is to be imprinted. It is also possible that said carrier is configured for carrying multiple substrates. It is possible that the system is configured such that the distance between at least one spray valve and at least one carrier is adjustable. It is also possible that the distance between at least one primer liquid applicator and at least one carrier is adjustable and / or that the distance between at least one resin applicator and at least one carrier is adjustable. This could further optimize control of the priming and / or resin deposition process. The system could further comprise at least one transport unit for transport or at least one carrier and / or at least one substrate. Said transport unit could for example comprise at least one air bed, a plurality of rollers, a belt, an interface with substrate handler and / or combinations thereof.

[0040] Preferably, at least one spray valve comprises an air atomizing spray nozzle. At least one spray valve may thereby comprise at least one fan configured to optimize the primer liquid jet. It is imaginable that at least one control unit is configured to control and / or adjust the fan air pressure of at least one fan of at least one air atomizing spray nozzle. The fan air pressure is the pressure of the air that close to the primer liquid nozzle opening causes the jetted primer liquid to be atomized, or nebulized. A higher fan air pressure causes the spray pattern to stretch out and for example to become more oval-shaped. It is also imaginable that at least one control unit is configured to control and / or adjust the orientation of the fan of at least one air atomizing spray nozzle. This could further optimize control of the primer deposition process.

[0041] The system according to the invention may further comprise at least one flexible stamp configured for nanoimprinting, in particular roll-to-plate nanoimprinting. Any of the embodiments described for the system according to the invention also apply to the method according to the invention, and vice versa. The invention also relates to a system for nanoimprinting, comprising a at least one flexible stamp configured for nanoimprinting, in particular roll-to-plate nanoimprinting.

[0042] The invention will be further elucidated by means of non-limiting exemplary embodiments illustrated in the following figures, in which:

[0043] - figures 1 a and 1 b show substrates subjected to a primer liquid application process according to the prior art;

[0044] - figures 2a-2d show methods for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting according to the present invention;

[0045] - figure 3 shows a substrate to which primer liquid and resin is applied for nanoimprinting purposes according to the present invention; and

[0046] - figures 4a-4c show spray valves as applied in a method and system according to the present invention.

[0047] Within these figures, similar reference numbers correspond to similar or equivalent elements or features.

[0048] Figures 1 a and 1 b show a schematic representation of substrates 10 which are subjected to a primer liquid 11 according to the prior art. The figures show a top view of the substrate 10. In the left part of the figure, the substrate 10 which is to be imprinted is free of primer liquid and resin. The figure then shows that the substrate 10 is provided with primer liquid 11 via spraying. It can be seen in figure 1 a that not the complete surface of the substrate 10 is covered with primer liquid. The further primer liquid layer is preferably substantially homogeneously provided over the surface of the substrate 10. Figure 1 b show that an excess of primer liquid 11 is applied in order to ensure that the substrate 10 is fully covered with primer liquid 11.

[0049] Figures 2a, 2b, 2c and 2d show a schematic representation of a method for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting according to the present invention. All figures show a top view of at least one substrate 110 which is subsequently provided with primer liquid 11 and resin 12. Figure 2a shows a sequence wherein first a plain substrate 110 is shown, subsequently a primer liquid 11 is applied to the substrate via spraying using at least one spray valve 120. Typically, the primer liquid 11 has a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s . The primer liquid 11 is applied to the substrate 110 in a first predetermined pattern, wherein the layer thickness of the applied primer liquid 11 differs per section. It can be seen that a first primer liquid section 11 a has a first layer thickness, a second primer liquid section 11 b has a second layer thickness and a third primer liquid section 11 c has a third layer thickness. In a next step, at least one resin 12 is applied to the substrate 110 via droplet deposition. The resin typically has a viscosity in the range of 0.1 to 50,000 mPa-s, in particular 1 to 1 ,000 mPa-s, more in particular 10 to 200 mPa-s. The resin 12 is applied to the primed substrate 110 via a resin droplet applicator 121 in a second predetermined pattern which overlaps with the first predetermined pattern formed by the primer liquid. Figure 2b shows a similar configuration as seen in figure 2a. However, in this process the primer liquid 11 is applied in an excess in order to ensure that the substrate 110 is fully covered with primer liquid 11 . Further, the first predetermined pattern is formed by two first primer liquid sections 11a having a first layer thickness which enclose a second primer liquid section 11 b having a second layer thickness. The second layer thickness can for example be twice the layer thickness of the first layer thickness. Figure 2c shows a substrate 110 which defines multiple sections 110a-110f, or active areas 110a-110f. These specific sections 110a-110f are configured to be imprinted whilst the further parts of the substrate 110 should stay clean. Therefore the primer liquid 11 is specifically applied to the active areas 110a-110f of the substrate 110. In the shown embodiments, the primer liquid 11 is applied such that the region outside the active areas 110a-110f are provided with a larger layer thickness of primer liquid. These so called outflow / overflow areas are located outside the active areas 110a-110f, and applying a thicker primer layer can ensure that excess resin 12 sticks to the substrate 110 and not to the stamp applied for imprinting. The right part of the figure shows that the resin 12 is applied in droplets on part of the active areas 110a-110f. The flexible stamp applied in the roll-to-plate imprinting process will spread the resin 12 over the active areas 110a- 110f during the imprinting process. Figure 2d shows yet another embodiment, wherein multiple substrates 110 are provided which are positioned upon a carrier 130. The primer liquid 11 is applied in three different layer thickness 11 a, 11 b, 11 c varying per substrate 110. It can be seen that the amount of resin 12 applied is based on the applied primer liquid layer thickness 11a, 11 b, 11c. Figure 3 shows a yet another example of substrate 210 to which primer liquid 11 and resin 12 is applied for nanoimprinting purposes. The figure shows a substantially straight and flat substrate 210 upon which four active areas 210a- 21 Od are indicated. The resin 12 is spread out over an area which covers the active areas 210a-210d completely. The primer liquid 11 is provided in an ever larger area which is larger than the area defined by the resin 12. However, the area defined by primer liquid 11 is smaller than the total area of the substrate 210. The borders of the first predetermined pattern defined by the primer liquid are at a distance d1 , d2 from the outer edges of the substrate 210.

[0050] Figures 4a-4c show spray valves as applied in a method and system according to the present invention. The figures show a schematic representation from a side view. The figures show spray valves 120 which are configured to spray primer liquid 11 to a substrate, in particular primer liquid 11 having a viscosity in the range of 0.001 to 1 ,000 mPa-s, in particular 0.01 to 100 mPa-s, more in particular 0.1 to 10 mPa-s. The spray valves 120 may be comprised in a primer liquid applicator. The spray valves 120 comprise a liquid channel 122, or fluid supply line 122, for supplying primer liquid. The dimension of at least one opening in at least one liquid channel 122 and / or in the nozzle opening 123 can be adjusted in particular via a stroke 124. The spray valves 120 further comprise a control air hose 125 and a nozzle fan air hose 126.

[0051] Figure 4a shows two adjacent spray valves 120 which are positioned at a distance Da, or pitch, from each other. The spray valves 120 are configured to spray a substantially oval shaped primer liquid beam. Whereas in figure 4a the spray valves 120 are positioned such that the primer liquid 11 supplied by the adjacent spray valves 120 does not overlap. The configuration of figure 4b shows that the distance Db, or pitch, between the adjacent spray valves 120 is smaller such that the primer liquid 11 supplied by the adjacent spray valves 120 partially overlaps. This enables that a larger layer thickness of primer liquid 11 can be obtained during a single spray. It is possible within the context of the present invention that a control unit is applied to control the mutual distance, or pitch, between at least two adjacent spray valves 120, and preferably between multiple adjacent spray valves 120. Figure 4c shows the effect of adjusting at least one parameter of the spray valve 120. It can be seen what the effect of the fan air pressure is with respect to the spray shape of the primer liquid. A higher fan air pressure will result in a smaller bundle H whereas a lower fan air pressure will result in a wider bundle L. It will be clear that the invention is not limited to the exemplary embodiments which are illustrated and described here, but that countless variants are possible within the framework of the attached claims, which will be obvious to the person skilled in the art. In this case, it is conceivable for different inventive concepts and / or technical measures of the above-described variant embodiments to be completely or partly combined without departing from the inventive idea described in the attached claims.

[0052] The verb 'comprise' and its conjugations as used in this patent document are understood to mean not only 'comprise', but to also include the expressions 'contain', 'substantially contain', 'formed by' and conjugations thereof.

Claims

Claims1 . Method for controlled application of primer liquid and resin onto a substrate for roll-to-plate nanoimprinting, comprising the steps of:- applying at least one primer liquid to at least one substrate via spraying, wherein at least one primer liquid has a viscosity in the range of 0.1 to 10 mPa-s; and subsequently- applying at least one resin to the at least one substrate via droplet deposition, wherein at least one resin has a viscosity in the range of 5 to 2,000 mPa-s; wherein at least one primer liquid is applied to the at least one substrate in a first predetermined pattern and wherein at least one resin is applied to the at least one substrate in a second predetermined pattern, wherein at least part of the second predetermined pattern overlaps with the first predetermined pattern.

2. Method according to claim 1 , wherein at least one primer liquid is applied to a predetermined part of the at least one substrate such that the area defined by primer liquid is smaller than the total area of the at least one substrate.

3. Method according to any of the previous claims, wherein at least part of the first predetermined pattern has a non-homogeneous thickness distribution of primer liquid.

4. Method according to any of the previous claims, wherein at least part of at least one primer liquid is applied to the at least one substrate in a variable layer thickness.

5. Method according to any of the previous claims, wherein at least part of the first predetermined pattern and at least part of the second predetermined pattern mutually differ.

6. Method according to any of the previous claims, wherein at least one primer liquid is applied via at least one spray valve and preferably via multiple spray valves.

7. Method according to claim 6, wherein the spray valve height of at least one spray valve, the velocity of displacement of at least one spray valve, the orientation of at least one spray valve and / or the displacement pattern of at least one spray valve is controlled and / or adjusted during application of at least one primer liquid to the at least one substrate.

8. Method according to any of the previous claims, wherein at least one resin is applied via at least one jet valve and / or piezo actuated valve.

9. Method according to any of the previous claims, wherein at least one resin is applied to the at least one substrate in an interrupted pattern.

10. Method according to any of the previous claims, wherein the first pattern comprises at least two pattern sections which are at a distance from each other.11 . Method according to any of the previous claims, wherein at least one primer liquid has a viscosity in the range of 0.3 to 8 mPa-s, preferably in the range of 0.5 to 5 mPa-s, more preferably in the range of 1 to 3 mPa-s.

12. Method according to any of the previous claims, wherein at least one resin has a viscosity in the range of 5 to 150 mPa-s, preferably in the range of 10 to 100 mPa-s, more preferably in the range of 15 to 75 mPa-s.

13. Method according to any of the previous claims, comprising the step of imprinting at least part of the resin.

14. Method according to any of the previous claims, wherein at least part of the first predetermined pattern and at least part of the second predetermined pattern are adjacent to each other, and wherein a transit region is present at least at a part of at least one side edge of the first predetermined pattern, wherein the transition region is defined as a region wherein a part of the second predetermined pattern adjacent to a part of the first predetermined pattern transits into an overlapping part of the first predetermined pattern and the second predetermined pattern.

15. System for controlled application of primer liquid and resin onto a substrate in particular for roll-to-plate nanoimprinting in particular via the method according to any of the previous claims, comprising:- at least one primer liquid applicator for applying at least one primer liquid to at least one substrate which is to be imprinted, said primer liquid applicator comprising at least one spray valve configured for spraying at least one primer liquid having a viscosity in the range of 0.1 to 10 mPa-s;- at least one resin applicator for applying at least one resin with a viscosity in the range of 5 to 2,000 mPa-s to the at least one substrate via droplet deposition; and- at least one control unit configured to control and / or adjust at least two parameters of the at least one primer liquid applicator (in particular) during application of primer liquid onto the at least one substrate, wherein the parameters are chosen from the group of: the spray valve height of at least one spray valve, the primer liquid flow rate from at least one spray valve, the velocity of displacement of the at least one primer liquid applicator, the orientation of at least one spray valve and / or of at least one spray valve, the displacement pattern of the at least one primer liquid applicator and / or of at least one spray valve.

16. System according to claim 15, wherein at least one control unit is configured to control and / or adjust at least one parameter of at least one spray valve, wherein at least one parameter is chosen from the group of: the fan air pressure, the primer liquid pressure, the spray valve stroke setting, the primer liquid flow rate, and / or the spray shape.

17. System according to claim 15 or 16, comprising multiple spray valves, wherein at least two spray valves are positioned substantially parallel to each other.

18. System according to claim 17, wherein at least one control unit is configured to control the mutual distance between at least two adjacent spray valves.

19. System according to any of claims 15 to 18, wherein at least one control unit is configured to control at least one parameter of the at least one resin applicator during the application of resin onto the at least one substrate, wherein theparameters are chosen from the group of: the height of the at least one resin applicator, the velocity of displacement of the at least one applicator, the displacement pattern of the at least one resin applicator, and the resin flow rate.

20. System according to any of claims 15 to 19, comprising at least one liquid channel for supplying at least one primer liquid to at least one spray valve, wherein at least one control unit is configured to control and / or adjust the dimension of the opening in at least one liquid channel that supplies primer liquid to the spray valve.21 . System according to any of claims 15 to 20, wherein at least one primer liquid applicator, and in particular at least one spray valve thereof, is configured for applying at least one primer liquid with a non-homogeneous thickness distribution over the surface over at least one substrate which is to be imprinted.

22. System according to any of claim 15 to 21 , comprising at least one carrier for carrying at least one substrate which is to be imprinted.

23. System according to claim 22, wherein the distance between at least one spray valve and at least one carrier is adjustable.

24. System according to any of claims 15 to 23, wherein at least one spray valve comprises an air atomizing spray nozzle.

25. System according to any of claims 15 to 24, comprising at least one flexible stamp configured for nanoimprinting.

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