Patent Application
20190314849
The present invention relates generally to aerosol printing and, more particularly, to filters for aerosol printing systems.
Confluent aerosol printing is a system for material deposition that utilizes aerodynamic focusing to deposit a collimated stream of atomized ink droplets entrained in a gas stream onto particular substrates. While confluent aerosol printing technology is considered to be in its infancy, it is believed that the technology can lead to many potential commercial applications, such as the printing of novel small electronics (for example, interconnects) and electronic components (for example, resistors, capacitors, thin film transistors, etc.).
Referring to
After the aerosol 34 is formed in the atomizing chamber 22, the aerosol 34 is directed through an exit 36 of the atomizing chamber 22 to the deposition module 24. The deposition module 24 generally includes flexible tubing 38 and the print nozzle assembly 40. The flexible tubing 38 directs the aerosol 34 from the atomizing chamber exit 36 to the print nozzle assembly 40. The print nozzle assembly 40 is intended to focus and collimate the aerosol 34 into a tight stream of droplets 42 using an aerodynamic lens 44. The aerodynamic lens 44 includes a centrally disposed ink channel 46 and a concentric and converging sheath gas channel 48. In operation, sheath gas (indicated by arrows 50 pointing towards the sheath gas channels 48) from a sheath gas supply 52 and aerosol 34 converge within the print nozzle assembly 44 to focus and direct the aerosol 34 into the tight stream of droplets 42 that exits a nozzle 54 toward a substrate (not shown) positioned at a distance away from the nozzle 54.
As noted above, the aerosol 34 produced in the atomizing chamber 22 and delivered to deposition module 24 is comprised of droplets 32 having a relatively wide range of dimensions (i.e., the aerosol 34 is considered to be a “polydisperse population” of droplets 32). It has been found that the ability of the deposition module 24, and particularly the print nozzle assembly 40 of deposition module 24, to focus and collimate the aerosol 34 into the tight stream of droplets 42 is limited by (1) the relatively higher inertia of the larger aerosol droplets 32 within the polydisperse population; and (2) the relatively higher diffusivity of the smaller aerosol droplets 32 within the polydisperse population. Even when good focusing is achieved, a minimum deposited feature size on the substrate is limited by the largest aerosol droplets 32 of the tight stream of droplets 42. For example, a 1 μm droplet in the polydisperse population may produce a 10 μm diameter spot on the substrate—of course this is dependent upon additional factors, such as wicking, contact angle, etc.
Additionally, as the aerosol 32 travels from the atomizing chamber 22 to the print nozzle assembly 40, a portion of the aerosol 32 may condense and deposit onto an inner surface of the flexible tubing 38, the atomizing chamber exit 36, and any other structures along the aerosol flow path between the atomizing chamber 22 and the print nozzle assembly 40 (illustrated as a consolidated drop 56 within the tubing 38. Sufficient accumulation of ink along these inner surfaces may result in the formation of larger drops that flow along the surfaces to the print nozzle assembly 40. Formation of these large drops may induce clogging, partial or complete, within the print nozzle assembly 40 if permitted to enter the small diameter (e.g., less than 500 μm) nozzle 54. In most cases, this clogging phenomenon is the limiting factor that determines system runtime and throughput as clogs typically result in ruined samples and require that the deposition module 24 or components thereof (such as the print nozzle assembly 40) be disassembled and cleaned or replaced.
In view of the above and other considerations, there is a need for an improved confluent aerosol printing system that reduces or eliminates the difficulties associated with a polydisperse population of aerosol droplets within an aerosol stream. There is also a need for a confluent aerosol printing system that can effectively handle or avoid troublesome ink accumulation within components of the deposition module of an aerosol printing system.
The present invention overcomes the foregoing problems and other shortcomings, drawbacks, and challenges of conventional aerosol printing system resolution. While the invention will be described in connection with certain embodiments, it will be understood that the invention is not limited to these embodiments. To the contrary, this invention includes all alternatives, modifications, and equivalents as may be included within the spirit and scope of the present invention.
According to an embodiment of the present invention, a passive filter for an aerosol printing system includes a housing having a fluid inlet port at a first end and a fluid outlet port at a second end, the fluid inlet and outlet ports being coaxial. A chamber is disposed within the housing and has a ceiling, a base, at least one wall between the ceiling and the base, a chamber entrance in the ceiling, and a chamber exit. The chamber entrance and exit being coaxial to the fluid inlet and outlet ports. The chamber exit is disposed within chamber between the chamber entrance and the base and defining a circumferential trough about the chamber exit.
Other embodiments of the present invention include a passive filter for an aerosol system that includes a housing having a fluid inlet port at a first end and a fluid outlet port at a second end, the fluid inlet and outlet ports being coaxial. The housing includes first and second chamber. Each of the first and second chambers includes a respective ceiling, a base, at least one wall between the ceiling and the base, a chamber entrance in the ceiling, and a chamber exit. The chamber entrance and exit are coaxial to the fluid inlet and outlet ports, wherein the chamber exit is disposed within chamber between the chamber entrance and the base and defining a circumferential trough about the chamber exit.
Still other embodiments of the present invention include a passive filter printhead for an aerosol print system. The passive filter printhead has a housing having a fluid inlet port at a first end and an opposing second end, the fluid inlet port configured to receive an aerosol ink. A print nozzle configured to eject the aerosol ink is at the opposing second end of the housing, the print nozzle being configured to eject the aerosol ink. The fluid inlet of the housing and the print nozzle are coaxial. Between the fluid inlet port and the print nozzle is a passive filter that includes a chamber that is disposed within the housing. The chamber has a ceiling, a base, at least one wall between the ceiling and the base, a chamber entrance in the ceiling, and a chamber exit. The chamber entrance and exit being coaxial to the fluid inlet and outlet ports. The chamber exit is disposed within chamber between the chamber entrance and the base and defining a circumferential trough about the chamber exit. Expansion of the aerosol ink entering the chamber from the chamber entrance filters the aerosol ink.
According to one embodiment of the present invention, the above and other needs are met by a passive filter for a confluent aerosol printing system. The passive filter includes a housing including an inlet port configured to receive an aerosol from the aerosol printing system and an outlet port configured to transmit a filtered aerosol. The passive filter further includes a chamber disposed within the housing between the inlet port and the outlet port having a chamber entrance in a chamber ceiling that is in fluidic communication with the inlet port and having an entrance diameter; a chamber base; at least one wall extending between the chamber ceiling and the chamber base; a chamber exit within the chamber and that is in fluidic communication with the outlet port. The chamber exit is coaxial with the chamber entrance and may have an exit diameter that is equal to or less than the entrance diameter. A trough is formed between the chamber exit and the at least one wall. In operation, aerosol received through the inlet port of the housing is filtered as the aerosol flows through the chamber via expansion of the aerosol as the aerosol enters the chamber. Aberrant aerosol flows into the trough while filtered aerosol flows through the chamber exit to the outlet port of the housing.
According to certain embodiments, the inlet port, chamber entrance, chamber exit, and outlet port are coaxially aligned along an aerosol flow path.
According to certain embodiments, an angular wall extends between the chamber exit and the at least one wall to form the trough.
According to certain embodiments, the filter chamber includes an angular entrance wall or an antechamber at the ceiling.
According to certain embodiments, the housing includes a first housing portion including the inlet port and the chamber entrance and a second housing portion including the outlet port and the chamber exit. The first housing portion and the second housing portion may be removably coupled together for forming the filter chamber.
According to another embodiment of the disclosure, a passive filter for an aerosol printing system includes a housing having an inlet port configured to receive an aerosol from the aerosol printing system and an outlet port configured to transmit a filtered aerosol. The passive filter further includes a filter chamber disposed within the housing between the inlet port and the outlet port. The filter chamber includes a chamber entrance at a chamber ceiling, the chamber entrance being in fluidic communication with the inlet port and having an entrance diameter; a chamber base; and at least one wall extending between the chamber ceiling and the chamber base. A chamber exit is disposed in the filter chamber between the chamber entrance and the chamber base and has an exit diameter. The chamber exit is in fluidic communication and coaxial with the chamber entrance and the outlet port. The exit diameter is equal to or less than the entrance diameter. An angular wall may extend between the chamber exit and the at least one wall to form the trough. In operation, aerosol received through the inlet port of the housing is filtered as the aerosol flows through the chamber such that aberrant aerosol collects within the trough and filtered aerosol passes through the chamber exit.
According to certain embodiments, the inlet port, chamber entrance, chamber exit, and outlet port are each coaxial along the aerosol flow path.
According to certain embodiments, the filter chamber further includes an angular wall that extends away from the chamber entrance at the chamber ceiling towards one or more sidewalls of the filter chamber. According to some embodiments, the angular entrance wall is rounded.
According to certain embodiments, the housing further includes a chamber exit lumen for fluidly connecting the chamber exit to the outlet port.
According to certain embodiments, the housing includes a first housing portion including the inlet port and the chamber entrance and a second housing portion including the outlet port and the chamber exit. The first housing portion and the second housing portion may be removably coupled together for forming the filter chamber.
Yet other embodiments of the present invention are directed to a method of filtering an aerosol of an aerosol printing system by directing the aerosol into a filter chamber through a chamber inlet, the filter chamber comprising a ceiling having the chamber entrance, a base, at least one wall between the ceiling and the base, and a chamber exit disposed within chamber between the chamber entrance and the base and defining a circumferential trough about the chamber outlet, wherein the chamber entrance and exit are coaxial. The aerosol expands within the filter chamber. Aberrant aerosol is captured within the trough while filtered aerosol passes through the chamber exit.
According to yet another embodiment of the disclosure, a method of filtering an aerosol in an aerosol printing system having an atomizing chamber in fluid communication with a print nozzle includes: providing a passive filter along an aerosol flow path between the atomizing chamber and the print nozzle, the passive filter including a filter chamber having a chamber entrance at a chamber ceiling and having an entrance diameter; a chamber base; a chamber exit within the chamber that is coaxial with the chamber entrance and having an exit diameter that is equal to or less than the entrance diameter; at least one wall extending between the chamber ceiling and the chamber base; and a trough between the at least one wall and the chamber exit. Aerosol flows from the atomizing chamber along the aerosol flow path through the filter chamber of the passive filter to provide a filtered aerosol to the print nozzle. The flowing of aerosol includes receiving the aerosol through the chamber entrance, providing divergence of the aerosol flow as it enters into and traverses through the filter chamber, filtering the aerosol as the aerosol flows from the chamber entrance through the chamber exit, and collecting filtered aerosol droplets from the aerosol in the trough as the filtered aerosol flows through the chamber exit.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the present invention.
Other embodiments of the present invention will become apparent by reference to the detailed description in conjunction with the figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views.
It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the sequence of operations as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of various illustrated components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration.
Referring now to
Referring still to
Referring specifically to
A chamber exit 89, having an exit diameter that is less than or equal to the entrance diameter—such as in the illustrative embodiment wherein the exit diameter is less than the entrance diameter—is disposed within the chamber between the chamber ceiling 86 and the chamber base 87 so as to provide a trough 90 about the chamber exit 89 and at the chamber base 87. As illustrated, the trough 90 may be formed by providing an angular, interior wall 91 that extends downstream from the chamber exit 89. Thus, as the aerosol 16 is constricted by the chamber exit 89, filtered aerosol droplets flow down the one or more angular exit walls 91 towards the bottom of the one or more troughs 90. An angle of the annular wall 91 may vary with respect to vertical (i.e., the linear flow path), with typical angles ranging from about 55° to about 70°.
The chamber entrance 85 and the chamber exit 89 are generally coaxial such that an approximately linear flow path extends through the housing 70, from the inlet port 72 to the outlet port 78. According to the illustrated embodiment, the inlet port 72, the outlet port 78, the chamber entrance 85, the chamber exit 89, and the filter chamber 84 are all coaxial and provide a coaxial lumen through the housing 70.
As specifically illustrated in
Referring specifically to
The diverging aerosol 97 is collected and may coalesce within the trough 90 while the filtered aerosol 80 moves through the chamber exit 89 and outlet port 78 to the print nozzle assembly 66 (
Another aspect specific to the embodiment of
Referring now to
As shown, the chamber entrance 105a, 105, 105c, the chamber exit 109a, 109b, 109c, and the filter chamber 104a, 104b, 104c may be coaxial.
The particular embodiments of
Referring now to
As shown, the chamber entrance 117a, 117, 117c, the chamber exit 121a, 121b, 121c, and the filter chamber 116a, 116b, 116c may be coaxial.
The particular embodiments of
In
As shown, the inlet 128, outlet 130, chamber entrances 134a, 134b, the chamber exits 142a, 142b, and the filter chambers 132a, 132 may be coaxial.
A pathway 148 fluidically couples the first chamber exit 142a to the second chamber entrance 134b. While the first and second chambers 132a, 132b have similar shape and structures, one of ordinary skill in the art having the benefit of this disclosure would understand this to be merely exemplary and not limiting. In fact, some differences between the illustrated first and second chambers 132a, 132b may be noted. For example, the first chamber entrance 134a includes a flared wall 150, which is similar to the passive filter embodiment illustrated in
According to this embodiment, an aerosol (not illustrated in
As shown, the respective inlets 158a, 158b, 158c, chamber entrances 163a, 163b, 163c, chamber exits 168a, 168b, 168c, and the filter chamber 162a, 162b, 162c may be coaxial.
The embodiments of
Finally, with reference to
The filter chamber 182 includes a chamber entrance 184 having an entrance diameter at a chamber ceiling 188; a chamber base 190; at least one wall 192 extending between the ceiling 188 and the base 190; a chamber exit 194 that is disposed within the filter chamber 184 between the ceiling 188 and the base 190; and a trough 196 between the outlet 194 and the at least one wall 192. As noted above, an angular wall 198 may extend between the chamber exit 194 and the at least one wall 192 to form the trough 196.
As shown, the inlet 178, chamber entrance 186, the chamber exit 194, the outlet 180, and the filter chamber 184 may be coaxial.
Filtered aerosol (not shown in
While the present invention has been illustrated by a description of one or more embodiments thereof and while these embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and method, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.
Pursuant to 37 C.F.R. § 1.78(a)(4), this application claims the benefit of and priority to prior filed co-pending Provisional Application Ser. No. 62/656,178, filed Apr. 11, 2018, the disclosure of which is incorporated herein by reference in its entirety.
The invention described herein may be manufactured and used by or for the Government of the United States for all governmental purposes without the payment of any royalty.
| Number | Date | Country | |
|---|---|---|---|
| 62656178 | Apr 2018 | US |
