SYSTEMS AND METHODS FOR RESIDUAL MATERIAL COLLECTION IN LASER-ASSISTED DEPOSITION
In a laser-assisted deposition system, a uniform layer of material is coated onto a donor substrate at a coating system, and portions of the material are jetted from the donor substrate to a receiving substrate at a printing unit, leaving residual portions of the material on the donor substrate. In order to not waste the residual portions of the material, the donor substrate with the residual portions of the material is returned to the coating system where the residual portions of the material are aggregated into a blob and subsequently recoated onto the donor substrate. The blob may be formed by translating the residual portions of the material towards an interface formed by two coating rollers, a squeegee and the donor substrate, or a film and the donor substrate.
This application is a nonprovisional of, claims priority to, and incorporates by reference U.S. Provisional Application No. 63/268,969, filed on 7 Mar. 2022 and U.S. Provisional Application No. 63/268,867, filed on 4 Mar. 2022.
FIELD OF THE INVENTIONThe present invention relates to systems and methods for collecting residual material that remains on a donor substrate after laser-assisted deposition of the material from the donor substrate to a receiving substrate, allowing for immediate reuse of the collected residual material.
BACKGROUNDIn a laser-assisted deposition system, a uniform layer of material is coated onto a donor substrate at a coating system, and portions of the material are jetted from the donor substrate to a receiving substrate at a printing unit, leaving residual portions of the material on the donor substrate.
SUMMARY OF THE INVENTIONThe present inventor has recognized that in a system configured to print a solder paste material, or any other viscous material, using laser-assisted deposition in which the material is first coated on and then printed from a donor substrate, there are advantages afforded by collecting (or aggregating) residual portions of the material in such a fashion that the residual material can be immediately used for subsequent printing processes. To that end, in various embodiments, the present invention provides a printing system that coats the to-be-printed material on a donor substrate and thereafter prints the material to a receiving substrate via laser-assisted deposition. Following such printing, residual portions of the material that remain on the donor substrate are collected (or aggregated) in or near the area in which the initial coating of material was performed. Importantly, this collection (or aggregation) of the residual material is done so that the residual material remains on (or near) the donor substrate, allowing it to be immediately reused following its collection (or aggregation). If needed, the residual portions of the material can be supplemented by additional amounts of material before the printing is performed. The printing system may include one or more imaging arrangements for monitoring the progress and/or assisting in the control of the various processes.
In some embodiments of the invention, the printing system includes a coating system that creates a uniform layer of the printed material on the donor substrate. The term “donor substrate” should be recognized as meaning any suitable film or substrate on which the material to be printed may be coated for purposes of transport to the laser-based printing portion of the printing system. Where present, the coating system may include a syringe of the to-be-printed material and an air or mechanical pump that drives the material onto the donor substrate. The donor substrate is then moved towards and through a well-defined gap (e.g., between rollers or knives) to create a uniform layer of the printed material with a thickness that is defined by the gap. In some cases, the coating system may contain more than one material, thereby creating a possibility for printing a plurality materials onto the donor substrate in a controlled sequence and making it possible to print more than one material on the receiving substrate. Within the coating system, the donor substrate is translatable in a bidirectional fashion and in a controlled manner (e.g., while opening a gap between coating rollers), thereby allowing for collection of residual material from the donor substrate after a printing operation without contamination of the rollers and loss of the residual material.
In various embodiments of the invention, the printed material may be a solder paste or other metal paste(s) used for printed electronics, a metal paste or a ceramic paste, a highly viscous material, a wax material, a polymer material, a mixture of a polymer and a monomer material, a low viscosity material, a material that can be cured by ultraviolet (UV) or visible light or by heating, or a material that can be dried. The printing process may use a laser-based system that contains a laser (e.g., a high frequency laser) to enable jetting of the material from the donor substrate to the receiving substrate.
In some cases, collection (or aggregation) of the residual material is performed using a blade or a squeegee. By translating the donor substrate under the blade or squeegee, the residual material is collected (or aggregated) so that it remains on the donor substrate. The collection (or aggregation) is preferably performed in the vicinity of the coating system, for example, immediately upstream (as measured from the direction of travel of the donor substrate from the coating system to the printing unit) of the coating system so that the collected residual material and any supplemental material from the coating system may be immediately moved towards and through the well-defined gap, resulting in the donor substrate that has been recoated with a uniform layer of the to-be-printed material of a desired thickness that is ready for a subsequent printing operation.
In some embodiments of the invention, the coating system includes a gap control unit configured to maintain the dimensions of the well-defined gap. For example, the well-defined gap may be maintained by rollers, one or more of which is positionable with respect to the other or one another using actuators. The actuators may be piezoelectric actuators capable of small displacements in one or more dimensions, allowing for fine control of the gap width.
As noted above, the donor substrate may be any suitable film or substrate on which the material to be printed may be coated and, in some embodiments of the invention, may be a continuous or other transparent film substrate, a transparent film substrate coated by a metal layer or by a metal and a dielectric layer, or a transparent solid substrate. For example, the donor substrate may be a film substrate that, by rolling (under the influence of one or more motors or by being turned on a reel), can deliver the to-be-printed material from the coating system to the printing unit.
In accordance with various embodiments of the invention, a system that employs a narrow or contact gap printing system to effect printing of viscous materials, such as solder paste, performs an initial coating of the viscous material on a donor substrate. As part of this procedure, the donor substrate may be observed by one or more imaging arrangements for monitoring and control of the coating and subsequent printing and residual material recovery processes. The coated donor substrate is employed in printing of the viscous material to a receiving substrate. This printing procedure may involve the viscous material being distributed on the receiving substrate as dots (e.g., small, generally round spots or droplets) or other segments through a laser-assisted deposition or other laser dispensing printing operation, where the dots or other segments of the viscous material are ejected from a uniform layer thereof on the coated donor substrate onto the receiving substrate using a laser (e.g., a high frequency laser). Residual, un-jetted portions of the viscous material remaining on the donor substrate after the laser-assisted deposition or other laser dispensing printing operation are then recovered, preferably by returning the portion of the donor substrate with the residual material thereon to an area near (or within) the coating system and so that it remains on the donor substrate so that it is available for immediate reuse (optionally along with additional amounts of the viscous material applied to the donor substrate by the coating system). To ensure the uniform coating of the viscous material onto the donor substrate, the coating system used to coat the donor substrate may be a syringe and a gap system in which the viscous material is dispensed from a syringe (or other applicator) to the donor substrate which then passes through a well-defined gap (e.g., formed by blade of other kind of barrier, or a pair of rollers or cylinders). After passing through the gap, a uniform layer of the viscous material is present on the donor substrate and the laser assisted deposition / laser dispensing system can be used to jet dots of material from the coated, donor substrate to the receiving substrate. After providing the uniform layer of viscous material for printing, the donor substrate can be returned to the coating system (e.g., by linear translation in a reverse direction from that which it travelled to the printing area) for collection (or aggregation) of the residual material on the donor substrate and recoating thereof by the coating system to create a new uniform coated layer on the donor substrate for the next printing. As indicated above, the donor substrate may be a transparent film or other substrate, with or without a metal (or other) coating.
Systems configured in accordance with embodiments of the present invention may be used for printing a wide variety of liquid and/or paste materials. However, the present invention provides particular benefits for the printing of highly viscous materials that cannot be printed well in high resolution by other methods. For example, systems configured in accordance with embodiments of the present invention find particular application in printing solder pastes and other metal pastes, as well as high viscosity polymers, like acrylics, epoxies, and urethane-based adhesives, pastes or waxes. The present invention may also be employed in connection with the printing of temperature or oxygen sensitive materials since a coated, donor substrate can be maintained in a controlled environment prior to the printing process so as to avoid solvent evaporation or oxidation of the material to be printed.
The printing process, in which the viscous material is transferred from the donor substrate to the receiving substrate may make use of a laser-based system. For example, a printing head in the form of a laser (e.g., high frequency laser) may be used to selectively transfer dots or other segments of viscous material from the donor substrate to the receiving substrate. The laser (e.g., high frequency laser) may be arranged to scan the donor substrate in two dimensions so as to jet the dots or other segments of viscous material from the donor substrate to the receiving substrate. After being printed to the receiving substrate, the viscous material disposed on the receiving substrate may be cured by UV or infra-red light or dried by a heater, or may be subsequently transferred from the receiving substrate to another substrate by a further printing process.
These and further embodiments of the invention are described in detail below.
The present invention is illustrated by way of example, and not limitation, in the figures of the accompanying drawings, in which:
In system 100, a coating system 104 creates a uniform layer 106 of the to-be-printed material 108 (e.g., a highly viscous material such as a solder paste or other metal paste(s), a ceramic paste, a wax material, a polymer material, a mixture of a polymer and a monomer material, or a low viscosity material) on a donor substrate 110. In the illustrated example, the coating system 104 includes a syringe (or other applicator) 112 of the to-be-printed material and an air or mechanical pump (not shown) that drives the material, under the control of a controller (not shown), onto the donor substrate 110. The donor substrate 110 is then moved, using rollers 114, which may be driven under the control of the controller by motors (not shown), toward a well-defined gap 116 between coating rollers 118a, 118b or knives (not shown) to create the uniform layer 106 of the to-be-printed material with a thickness that is defined by the gap 116. As will be apparent, the donor substrate 110 can be translated bidirectionally in a controlled manner, while widening the gap 116 between the coating rollers 118a, 118b, allowing for recoating of the donor substrate 110 with reclaimed residual portions of the material that are not consumed during a printing process without contamination to the rollers 118a, 118b. This not only reduces the amount of donor substrate 110 consumed during the printing process, but also prevents waste of the to-be-printed material as any residual material from a printing process can be used in subsequent iterations of that process.
Although not shown in detail in these figures, the coating system 104 and, optionally, the laser-based scanning print system 120 may be housed inside a closed cell with a controlled environment (cold or hot) in order to prevent evaporation of solvent from the to-be-printed material or to prevent material oxidation, thereby prolonging the pot life of the material. In some embodiments of the invention, the coating system 104 contains more than one material, thereby allowing a plurality of materials to be printed onto the donor substrate 110 in a controlled sequence and making it possible to print more than one material on a receiving substrate 122.
Alternatively, actuator 124 may be configured to drive a lead screw to translate coating roller 118b towards or away from coating roller 118a. Additionally, although only a single actuator 124 is shown, in some embodiments a second actuator may be associated with coating roller 118a and the respective positions of the two coating rollers may be adjustable independently or collectively with respect to one another using individual actuators. As shown in the illustrated example, coating roller 118b may carry a film or other substrate 126 to aid in creating the uniform layer 106 of material on donor substrate 110. Accordingly, the substrate 126 may be tensioned so as to eliminate any slack when the coating roller 118b is translated towards or away from coating roller 118a.
As the to-be-printed material 108 is dispensed, or upon completion of an initial dispensing thereof, the donor substrate 110 is advanced so as to cause the to-be-printed material 108 thereon to be passed through the gap 116 between coating rollers 118a, 118b. As shown in
In
After such printing, a residual amount 132 of material 108 will remain on the donor substrate 110. In accordance with embodiments of the present invention, this residual material 132 may be returned to the coating system 104 for reuse. As shown in
By returning the residual material 132 on donor substrate 110 to the coating system 104, the residual material 132 can be reused. As shown in
Depending on the amount of residual material 132 recovered into blob 138, additional amounts of material 108 may be needed for a subsequent printing operation. As shown in
In some embodiments, rather than a squeegee 136, a separate film may be used to aid in the collection of the residual material 132. For example, a film carried by one or more rollers may be moved into position atop the donor substrate 110 and the donor substrate 110 advanced towards the interface with the film. The residual material 132 will collect upstream of that interface and thereby be available for use.
In other embodiments, the squeegee 136 may be positioned so as to collect residual material 132 on the donor substrate 110 as the donor substrate 110 is returned to the coating system 104. That is, the squeegee 136 may be positioned upstream of the gap 116 (with the stream direction referring to the original direction and not the reverse direction) so that the residual material 132 is collected into a blob as the donor substrate 101 travels in its reverse direction, thereby avoiding the need to separately position the squeegee 136 and have the donor substrate 110 travel in its original direction for collection of the residual material. This will result in the residual material being collected further upstream from the gap 116 than is the case according to the above-described method, however, in some cases it may be preferable or at least permissible to do so.
Thus, systems and methods for collecting residual material that remains on a donor substrate after laser-assisted deposition of the material from the donor substrate to a receiving substrate, allowing for immediate reuse of the collected residual material have been described. Although not illustrated in detail, it should be appreciated that the various components of the systems described herein operate under the control of one or more controllers, which, preferably, are processor-based controllers that operate under the instruction of machine-executable instructions stored on tangible machine-readable media. Such controllers may include a microprocessor and memory communicatively coupled to one another by a bus or other communication mechanism for communicating information. The memory may include a program store memory, such as a read only memory (ROM) or other static storage device, as well as a dynamic memory, such as a random-access memory (RAM) or other dynamic storage device, and each may be coupled to the bus for providing and storing information and instructions to be executed by the microprocessor. The dynamic memory also may be used for storing temporary variables or other intermediate information during execution of instructions by the microprocessor. Alternatively, or in addition, a storage device, such as a solid state memory, magnetic disk, or optical disk may be provided and coupled to the bus for storing information and instructions. The controller may also include a display, for displaying information to a user, as well as various input devices, including an alphanumeric keyboard and a cursor control device such as a mouse and/or trackpad, as part of a user interface for the printing system. Further, one or more communication interfaces may be included to provide two-way data communication to and from the printing system. For example, network interfaces that include wired and/or wireless modems may be used to provide such communications.
Claims
1. A printing system, comprising a coating system configured to create a uniform layer of a material on a donor substrate, and a printing unit configured to transfer the material in portions from the donor substrate onto a receiving substrate such that residual portions of the material remain on the donor substrate, wherein the printing system is configured to return the donor substrate having the residual portions of the material remaining thereon to the coating system for reclamation of the residual portions of the material on the donor substrate,
- wherein the coating system includes a dispenser of the material to deposit the material onto the donor substrate, and the coating system is further configured to transport the donor substrate with the material thereon towards and through a gap with a first gap width defined by a first coating roller and a second coating roller to create the uniform layer of the material on the donor substrate, the uniform layer of the material having a thickness that is defined by the first gap width, and
- wherein the reclamation of the residual portions of the material on the donor substrate is effected (i) by modifying the gap to have a second gap width that is narrower than the first gap width, and (ii) using a film at least partially disposed within the gap to aggregate the residual portions of the material on the donor substrate while the residual portions of the material are translated towards an interface between the film and the donor substrate, the interface disposed within the gap.
2-5. (canceled)
6. The printing system of claim 1, wherein the material comprises one of: a solder paste, a metal paste, a ceramic paste, a viscous material, a wax material, a polymer material, a mixture of the polymer and a monomer material, a low viscosity material, an ultraviolet (UV)-curable material, a heat-curable material, or a dryable material.
7. The printing system of claim 1, wherein the printing unit comprises a laser-based system that includes a laser configured to jet the portions of material from the donor substrate to the receiving substrate.
8. The printing system of claim 1, wherein the donor substrate is a film substrate and the printing system further comprises rollers to transport the donor substrate from the coating system to the printing unit.
9. A method, comprising:
- creating a uniform layer of a material on a donor substrate using a coating system which includes a syringe of the material, wherein the uniform layer of the material is created by: dispensing the material from the syringe onto the donor substrate, and transporting the donor substrate with the material thereon towards and through a gap with a first gap width defined by a first coating roller and a second coating roller, the uniform layer of the material having a thickness that is defined by the first gap width;
- printing portions of the material from the donor substrate to a receiving substrate by a printing unit; and
- recapturing residual portions of the material on the donor substrate for reuse by returning the donor substrate having the residual portions of the material to the coating system and aggregating the residual portions of the material on the donor substrate at the coating system,
- wherein the residual portions of the material are aggregated by (i) modifying the gap to have a second gap width that is narrower than the first gap width, and (ii) using a film at least partially disposed within the gap to aggregate the residual portions of the material on the donor substrate while the residual portions of the material are translated towards an interface between the film and the donor substrate, the interface disposed within the gap.
10-13. (canceled)
14. The method of claim 9, wherein the material comprises one of a solder paste, a metal paste, a ceramic paste, a viscous material, a wax material, a polymer material, a mixture of the polymer and a monomer material, a low viscosity material, an ultraviolet (UV)-curable material, a heat-curable material, or a dryable material.
15. The method of claim 9, wherein the printing unit comprises a laser-based system that includes a laser and the portions of the material are printed from the donor substrate to the receiving substrate by jetting the portions of material from the donor substrate to the receiving substrate using the laser.
16. The method of claim 9, wherein the donor substrate is a film substrate and the method further comprises transporting by one or more rollers the donor substrate from the coating system to the printing unit.
17. The method of claim 9, wherein returning the donor substrate having the residual portions of the material to the coating system comprises:
- modifying the gap to have a third gap width that is wider than the first gap width; and
- translating the donor substrate with the residual portions of the material through the gap having the third gap width.
Type: Application
Filed: Feb 13, 2023
Publication Date: Sep 7, 2023
Inventor: Michael Zenou (Hashmonaim)
Application Number: 18/168,057