Patent Grant
7735945
The present invention is in the field of switching, manipulating or modulating acoustic, electromagnetic, and electrical waves, energies, and potentials inexpensively, and optionally, on a highly integrated microscopic scale. All forms of such energies except visible optical-energy or visible optical-energy components are included.
Acoustic energy is increasingly utilized, directly or indirectly, in a large number of fields, including medical ultrasound diagnostic imaging, thermal bubble-jet inkjet personal printers, piezo-jet inkjet personal printers, non-destructive testing, sonar, and microphone technologies, to name a few. Distance sensors, mass-sensors, fluid-level sensors, and many security sensors also incorporate acoustic and ultrasonic devices. Emerging applications include the use of ultrasound to manipulate fluids or analyze samples on a microscopic scale within lab-on-a-chip devices. All of these involve the controlled application, passage or manipulation of acoustic waves created in a variety of manners.
Of substantial value would be the ability to switch, redirect or modulate the propagation of acoustic waves at low cost and on a fine scale amenable to micro-integration. This would allow reconfiguration of acoustic-based systems and components in a rapid dynamic manner on a grand scale, perhaps even in real time. This is not currently possible at low cost or on a fine scale. The acoustic waves we will manipulate are typically traveling in some sort of acoustic material or waveguide, such as in a gas-filled waveguide, liquid-filled waveguide, solid waveguide or in a substrate having technically useful acoustic or electroacoustic properties, such as lithium niobate. In any event, all such waves can be manipulated in accordance with the teachings of the invention in at least one of its embodiments. We also note that acoustic waves can take many forms such as bulk waves and surface waves of various well-known types, and the teachings of the present invention can be applied to one or more of these types separately or even simultaneously.
Likewise, RF (radio-frequency) energy and other high frequency electromagnetic waveforms are increasingly being employed in communications, radar, tracking devices, GPS (geopositioning systems), and in recent efforts to utilize terahertz electromagnetic energy to do medical diagnostic imaging and airport security screening. A similar means of inexpensively switching, modulating or redirecting such energies cheaply, and particularly on a fine scale, would be attractive. Potential applications include reconfigurable antennas, power-efficient personal communication devices, miniature security scanners, and self-healing electronic systems.
It would also be attractive to have a means of modulating electrical currents passing-through or potentials applied-to conductive-liquid microfluidic channels. Conductive liquids through which some electrical current flows, for example, are used in some continuous inkjet printers.
In these manners, one could implement networks or arrays of acoustic, electromagnetic or electrical-energy propagation switching, redirection and modulation devices using coplanar IC-style integration or other MEMs-like techniques in two- or three-dimensions. This would particularly have a large impact on what is possible in a consumer or mobile product. For RF devices, the present invention is seen as providing an additional tool with which to manipulate RF beyond existing FET switches and PIN diodes.
One prior art reference that we identified that may be relevant is “Switching Fiber-Optic Circuits with Microbubbles” by John Uebbing, appearing in Sensor Magazine in May 2003. In short, Uebbing utilizes thermally-formed microbubbles, such as the type employed in inkjet printing technology, to block or allow the propagation of light used in fiber-optic data lines-in the form of a bubble-based light switch. The bubbling-switch of their article is provided as a MEMS-based or micromachined bubble-array switch to compete with Texas Instruments DLMs™ or digital light mirrors, which are also useable as switch arrays for fiber-optic signals. Advantages are very high switching density at very low cost. As will be shown below, however, this reference is fundamentally different from our claimed invention.
We utilize the formation and manipulation of microbubbles or microdroplets of (preferably) flowable materials, such as liquids and gases, to beneficially control, redirect or modulate acoustic-energy propagation, electromagnetic-energy propagation or electrical potential and current application.
By “acoustic energy”, we mean any acoustic energy having an order of magnitude frequency between a milliHertz and several gigahertz or even terahertz. By “electromagnetic propagation”, we mean the passage or application of any electromagnetic energy, voltage or current other than visible optical electromagnetic energy. Such would include RF radiofrequency energies in the megahertz, gigahertz and terahertz ranges, direct currents (DC), alternating currents (AC), and applied electrical potentials (voltages) even with no current flowing. Thus, on the electromagnetic side, we are talking about everything from DC static potentials all the way up to but not including visible optical frequencies and above such visible optical frequencies. The reader will also be aware that certain electromagnetic signals can be polarized, such as in radar gigahertz-range systems, and we include all such signals having such polarizations in the scope. We note that the X-ray and gamma-ray ranges of electromagnetic energy are also covered as they are above the visible optical range.
In fundamentally different fields, applications, and realms of energy, we recognized that microbubbles, for example, could also be used to switch the propagation of (or application of) acoustic energy, electromagnetic energy or potential such as RF and DC/AC electrical power and potential. The reader will realize that to do this, different kinds of energies or potentials require different properties of the fluid (or bubble) to be manipulated. For example, for acoustic microswitching, the acoustical impedance and acoustic attenuation of the fluid/bubble are important, whereas these are not important for the referenced prior art visible optical energy microswitching. Thus, it clearly is not obvious to apply prior art optical microswitching to these alternative energies, which have different behavior and require different physical parameters be manipulated. In fact, it is not only the switching physics that is different, but the energy waveguides involved are also of known fundamentally different design.
Beginning with acoustic energy as an example, a lab-on-a-chip could utilize acoustics to at least one of pump or stir microvolumes of fluid reagents as by acoustic streaming or could utilize acoustics to spectrally analyze the composition or structure of solutions or mixture-specimens in such a chip. The existence of a vapor bubble, as formed by an in-situ heater in a microfluidic channel for example, would cause the propagating acoustic energy in the channel liquid to be blocked, reflected or redirected depending on the bubble geometry. This is because of the huge difference in acoustic impedance (and attenuation) between the liquid and the vapor. Further, the removal of a bridging liquid droplet could cause an open-circuit for acoustics traveling from one liquid or solid material to another. Acoustics is defined herein as infrasonic, sonic or ultrasonic energy, thereby possibly having frequency content from (orders of magnitude) 1 millihertz to 1 or more terahertz. We explicitly note that the energy to be switched, redirected or modulated, in accordance with the invention, need only interact with one of our inventive microbubbles or microdroplets. It does not require that the energy be delivered to and from that interaction site as by a waveguide, although a waveguide suitable for that energy will most commonly be employed. Thus, we see applications wherein microdroplets allow for bridging of an energy, perhaps acoustic energy, from one member or surface to another, possibly without any waveguides being involved.
Thus, we recognized that, depending on what media the acoustics is propagating within, the placement or removal of a vapor-bubble or liquid-droplet could serve to provide switching or modulation of the acoustic signals. There are any number of means of doing this such as by, but not limited to: a) forming a bubble in a liquid path, b) placing a remotely formed bubble into a liquid path, c) forming a droplet in a gap in an otherwise solid path, d) remotely forming a droplet and placing it in a gap in an otherwise solid path, or e) bridging between two surfaces via the interposing of a flowable material which can be selectively bridged via droplet or film formation or unbridged as by bubbling or film drainage or dewetting. Thus, our “microdroplets: and “microbubbles” in some cases may be large enough that they constitute films or layers typically but not necessarily having at least one macroscopic dimension.
We also note that by only partially blocking the path with a smaller bubble or droplet, for example, we can modulate the passing acoustics in amplitude to values between 100% and 0%. Acoustic practitioners will also recognize that by placing microbubbles in the acoustic path, say along a fluid-filled microchannel, that these bubbles change the acoustic behavior of the system. For example, if one has one or more spaced bubbles in the channel and they only partially span the width of the microfluidic channel, then they will modulate the passing acoustics because of their blocking/filtering properties and will also introduce new bubble resonances into the acoustic output. Thus, such bubble arrays can also be employed to favorably introduce or tune-in new spectral features as a function of how they change the resonant properties of the microfluidic system. Similarly, such bubbles can act as filters for particular frequencies at their resonance values. The acoustical behavior of bubbles and droplets has long been of scientific interest for ultrasonic-cleaning and related cavitating applications. We explicitly note that properties other than amplitude can also or instead be manipulated with our invention. For example, phase and polarization of RF and acoustic signals can be manipulated in known manners upon interaction with a bubble or droplet.
Practitioners of the acoustic arts are aware that the ability of a bubble to totally block acoustic propagation is primarily related to its high acoustic reflection coefficient due to the abrupt change in acoustic impedance traveling from fluid to the vapor (or gas) bubble. For an intermediate example, if one were to place a liquid microdroplet of a second foreign liquid in a first liquid, then, as long as there is some finite acoustic impedance difference between the two fluids, there will be some reflection and some transmission of the energy at the interspersed bubble as predicted by the impedance-derived reflection coefficients. Thus, interposed microdroplets of liquid (as opposed to vapor or gas) placed within a fluid waveguide can also modify or modulate acoustic propagation, albeit typically to a much lesser degree than a gas bubble in a liquid waveguide. Such microdroplets could also be introduced into the propagation path from a remote location outside of the waveguide itself, assuming a waveguide is employed.
Given the basic acoustic-microswitching concept, an acoustics practitioner will realize that the present invention can also be used to modify the surface of acoustic components such as acoustic mirrors and acoustic lenses such that the surfaces perform the switching or modulation functions described. For example, a metal acoustic-mirror can be modified by creating an array of microbubbles or microdroplets on its surface. These microbubbles or microdroplets will have numerous effects including selective diffractive and reflective cooperative or summed effects that are a predictable function of their spatial arrangement. Such switchable microbubbles or microdroplets will also allow the controlled introduction of phase-changes at such newly modified reflective surfaces. Preferably, microbubbles would be formed by in-situ heaters on fluid immersed (or coated) acoustic components whereas microdroplets would, for example, be condensed upon air or vapor-immersed acoustic components. Thus, something that looks like an acoustic mirror could have bubbles or droplets introduced in an array on (or in) its surface such that the “mirror” now serves also or instead to selectively redirect acoustic beams in certain desired diffraction directions determined by the bubble pattern and bubble size relative to the incoming acoustic wavelength.
Thus, it is possible to switch, redirect or modulate energy over a large region using one or more microdroplets, microbubbles, microfilms or assemblages thereof, including assemblages wherein individual microbubbles/droplets have or are combined into continuous films of flowable material such as gas or liquid. Note that our microbubbles or microdroplets are not necessarily spherical or roughly polyhedral when they are attached to surfaces. They can also be of extended dimension such as a very long bubble in a channel (waveguide) whose length is perhaps 10 or even 100 times its diameter (or cross-section). In many cases, the microdroplets or microbubbles will take the shape of their surroundings. As an example, a bubble grown in a square cross-section extended channel will have flattened surfaces that contact the channel walls but will have other curved surfaces facing the liquid. Depending on the energy or wavelength being manipulated, one may favorably choose the microbubble or microdroplet to favorably have at least one dimension which is a known multiple (or fraction) of that wavelength. As an example, an acoustic-manipulation droplet might be chosen such that its propagation-direction depth is a quarter wavelength of the acoustical energy such that it serves as an acoustic matching medium. Likewise, a droplet serving to block RF or electromagnetic energy could be chosen such that the incoming RF signal is attenuated within a known extinction range or reflected within a known reflection thickness of a droplet media. The “skin” effects of RF energy are well-known. Those familiar with switching RF will realize that physical parameters of the switching liquid such as dielectric constant, electrical conductivity, tan-delta (lossiness), and attenuation can be varied to achieve these purposes.
Thus, the scope of the invention includes the insertion into a path of acoustic propagation microbubbles, microdroplets or even extended microfilms of flow-able or vaporous materials which beneficially switch or modulate such acoustics or which allow modification of the acoustic behavior of the system due to the microbubbles etc. being new resonating or otherwise-deforming constituents of the system. In cases wherein such microbubbles or microdroplets appear in an array, one may also derive useful diffractive effects along particular angles of incidence. A blanket illuminating incoming acoustic beam could be purposely diffracted in predictable directions, including multiple simultaneous directions, by the known diffraction effects of arrayed scatterers. This could be useful for beam scanning and steering.
In the field of electromagnetic energy switching and manipulation, it is known, for example, that high frequency RF, as used in radar and the newly found field of terahertz medical diagnostic imaging, is reflected from surfaces which have a dielectric constant discontinuity and project a surface area onto the oncoming wave (have a reflective cross-section). Thus, if one has a gas- or vapor-filled waveguide for such energy and one interposes a droplet or body of conductive fluid in its path, one would know that one can reflect a portion of that energy, thereby providing a switch or modulator of that energy. Likewise, if the droplet is RF-dissipative, it can act as a modulator or attenuator and allow some energy to pass through it, depending on its thickness, dielectric constant, and losses. Since microscopic bubble and droplet making and moving techniques can be utilized to do this, it is possible to now manipulate electromagnetic energy propagation at a fine scale in a highly integrated manner. Note that one could also use a bubble, for example, to disrupt electrical current-flow or the application or electrical-potential through an electrically conductive liquid flowing (or sitting statically) in an electrically-insulating channel. In that case, one would simply break the conductive-liquid circuit with the electrically-insulating vapor bubble (or, alternately, with an electrically-insulating droplet). Included in the scope of the invention is the employment of semiconducting droplets and microbubbles that could allow for the formation of active electronic components such as diodes and transistors. These are, after all, modulators and switchers also.
The prior art field of RF signal-manipulation heavily utilizes PIN diodes and FET switches to switch and modulate RF signals. Recently, it has been shown that MEMs-based switches offer benefits over that prior art. In particular, it has been demonstrated that capacitance-based switching of RF is highly attractive. Along those lines, MEMs has been used to form electrostatically adjustable capacitors for such switching. In essence, an electrostatic deflection of a microbeam changes the gap of a capacitor and therefore the capacitance value. Such switches can be used to construct DMTLs or “distributed MEMs transmission lines”. These are known to be directly useable for constructing phase shifters, delay lines, variable and tunable filters, tunable resonators, and configurable antennas, for example. We realized herein that using our invention, we can provide an equivalent capacitor or capacitor-switch wherein the movable or deformable electrode or dielectric material is one of our droplets, bubbles or films, for example. Those familiar with making MEMS RF switches will be aware that doing this instead with a movable or deformable droplet can be much easier, cheaper, and more compact than doing it with MEMs components. Thus, by moving such a droplet, one could make a capacitance switch for RF and thereby also provide such useful circuit functions. It also allows for simpler MEMs rather than just the elimination of MEMs.
Therefore, a droplet fluid, flowable droplet or microbubble of the invention may have conductive or insulating properties and controlled dielectric constants, depending on which embodiment is implemented to manipulate which form of energy. By “flowable”, we mean fluidic flow, distortion of shape due to growth or applied forces or fields, transport of a preformed droplet or even condensation (or evaporation) of a droplet. In other words, “flow” is any creation, destruction or transport of our droplet or bubble, regardless of the mechanism used to cause or enable it. During such formation and/or destruction, new material interfaces are flowing and changing size and/or shape. The flowable material may be any flowable material under at-least some circumstances. Thus, for example, a solid wax could be melted to flow. A pseudo-solid gel could be flowed simply with pressure, forced displacement or pumping. A liquid, paste, cream, solution or mixture could have a bubble thermally formed therein, have a bubble injected under pressure into it, or have a different material droplet or microbubble placed in it. All of these involve the motion of material interfaces to create the microbubble or microdroplet.
a and 1b are perspective views, depicting a fluid or gas filled microchannel acting as an energy waveguide and the same waveguide when a microdroplet or microbubble is introduced therein to cause switching or modulation of the waveguide energy.
a and 3b are perspective views, depicting switching the aperture size or shape of an acoustic beam.
a and 4b each comprise a side elevational view and a plot of frequency and time, depicting the creation of new acoustic components contributing desired acoustic behavior to an acoustically propagating signal energy.
a and 5b are side elevational views depicting the switching or modulation of RF energy using a disposed reflecting or attenuative droplet.
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In
It should be clear that if vapor bubble 4 does not block the entire channel 2, then some of energy E1 will pass around or leak around the bubble and some will be reflected backwards and sideways from the bubble, depending on the exact bubble shape, size, and acoustic wavelength(s) which are propagating according to known acoustic reflection and refraction laws. Acoustic practitioners will also be aware that a minuscule amount of E1 may be detectable on the far side of the bubble 4 because of liquid to gas to liquid coupling known to be very weak but usefully effectively zero for most purposes.
Thus, one may utilize a bubble 4 or bubble-array to switch on and off acoustic energy, to modulate the intensity of acoustic energy, or to redirect acoustic energy as by reflection in a controlled direction down another channel, for example. We include in the scope the dynamic modulation of the bubble (or droplet) in terms of size, shape or position as well as bubble formation by any known microbubble formation method for purposes of achieving the switching, modulation or redirection of the invention. It is known that such microbubbles, for example, can be formed not only by thermally heated resistive films 5 but also by the impingement of a laser beam to cause a tiny hotspot or even by acoustic cavitation. Alternatively, one may have a preformed bubble that is pushed (or grown) into the channel 4 from a laterally disposed chamber or cavity (not shown). In this manner, for example, a bubble 4 could be grown inwards from two or more channel surfaces such that any remaining connecting meniscus of liquid is relatively symmetric in shape.
We emphasize in all of these embodiments of the invention herein that our switching bubbles droplets 4 may be implemented in channels, in channel arrays, on surfaces, between surfaces, in interfaces or even in permeable or porous materials in a bridging manner, etc. We look at all of them as components for building systems. We anticipate a common application to be the provision of an acoustic-source manifold along which there are arranged numerous bubble-decoupleable acoustic sub-devices which can selectively tap acoustic energy from the source manifold as it is locally needed.
Finishing with
Moving now to
Because of the presence of vapor bubble 4a in aperture or orifice 8b, we have no droplet emitted from aperture 8b, since the acoustic energy from emitter 6 cannot substantially pass through or around vapor bubble 4a. Thus, vapor bubble 4a, as formed in this example using thermally-heating thin films 5a, has effectively acted as an acoustic switch and a microfluidic switch because it has both blocked acoustic propagation and has also blocked fluid flow due to that acoustic energy. Now, looking at aperture 8c, we similarly see a bubble 4b formed by thin film heater 5b; however this bubble 4b does not completely block aperture 8c. Therefore, we see a droplet 9b which is likely smaller than droplet 9a and is directed at an angle with a different velocity vB. The angular emission of droplet 9b is due to the asymmetric fluid flow in orifice 8c caused by the asymmetric bubble location.
The point here is that we have used a monolithic piezoemitter 6 having only one hot lead and one ground lead and one switch (none of these shown) whose common single pulsed waveform has emitted droplets from multiple apertures which we switched on or off (or somewhere in between as for aperture 8c) using vapor bubbles. Given the concept, a number of inkjet applications become possible for our switching or modulating droplets and we will list some of them here. Not all microbubbles or microdroplets need be located at the exit orifices; some may be in the interior plumbing of the inkjet head or distribution manifold. Some inkjet-related applications include:
We emphasize that one may utilize one or more flowable liquids or inks 3 (In
A particular application of
We also note that an historic problem of thermal-type inkjet printers has been burning of the ink and buildup of ink residue at the thermal bubble-making resistors. If such buildup happens on heaters 5a or 5b in
We have taught the use of microbubbles for switching or modulating droplet emission events such as in the inkjet printer head of
Moving now to
It should now be obvious that one may dynamically and even selectively switch the bubble-forming means (resistive heaters on substrate 14 of
We emphasize that our bubble switches or modulators could alternatively be remotely situated from the piezo or other acoustics-producing means. Thus, one could use our bubble arrays much as spatial-light-modulators are used, namely, downstream from their actual optical source whose emissions they act upon. Such a device could be called a SAM or spatial acoustic modulator.
Moving now to
Moving now to
Now, if we change incoming energy E1 of
So we have here in
Our next embodiment, that of
Now moving to
For example, liquid 24 is chosen to have a dielectric constant different than air. Just about any liquid has a dielectric constant different than air, thereby causing some reflection and some absorbtion/attenuation of energy E4 in droplet 24. A hydrocarbon liquid or water, for example, would provide this effect and the effect would be larger the deeper the droplet is in terms of the number of wavelengths up to a known skin-depth. We include in the scope the removal or sinking of heat from droplet 24, as such heat may be generated by the desired electromagnetic attenuation.
Another liquid droplet 24 example would be an electrically conductive ferrofluidic droplet as moved into place by magnetic or electromagnetic forces. Such a conductive droplet will reflect most of the energy E4 and attenuate the rest, thereby acting as an RF switch. Ferrofluids are suspensions of magnetic particles in a carrier liquid that are clumped and moved via magnetic (or electromagnetic) forces. A mercury droplet could, alternatively, serve the purpose of blocking energy E4 also.
It will be recognized by those skilled in the art that one may, analogous to the acoustic embodiments, not only reflect and attenuate waves but redirect RF waves by controlled angled reflection and refraction. In essence, we are employing disposed and deformable droplets to form dynamically variable-shaped and tuned waveguides. This was not possible prior to these teachings.
It would be very attractive to be able to integrate millimeter and submillimeter RF waveguides into a substrate. For example, at 1 terahertz, the waveguide could be an electrically conductive channel (at least the channel walls are conductive) having width and dimension of about 0.3 mm, according to known design methods. We anticipate at least two generic approaches to utilizing this invention for such applications:
Disposition of reflective droplets to block, terminate or limit the dimension of a waveguide or of an active RF component such as a mixer or diode.
Filling of waveguides or volumes with the droplet liquid and subsequent formation of local bubbles which themselves now comprise waveguides or portions of active components-being gas-filled.
It will be apparent to the RF, microwave and higher-frequency engineer that such bubbles and droplets, formed and disposed in any manner (such as by in-situ thin film heaters) provide a fundamentally new tool to dynamically change and adapt RF circuits and to also provide adjustment and tuning to RF components which have until now been fixed in behavior and arrangement. One or more bubbles or droplets may be combined to create a combined shape that, for example, has one-quarter wavelength characteristic dimension, as known in the art. Further, the inventive microdroplets, microbubbles or microfilms could also be employed to form waveguides. As an example, an elongated vapor bubble in a conductive liquid could serve as an electromagnetic waveguide.
Finally, we turn to
The foregoing description has been directed to explaining the drawings. With that description now in hand, the following further details are provided.
The present invention is directed to an energy switching, modulation or redirection device comprising:
In the use of the device, the energy preferably, but not necessarily, passes or is passed through or along a substrate or waveguide before and/or after the switching, modulation or redirection.
Also, the droplet, bubble or film is preferably at least one of formed or manipulated by at least one of a) a heater, b) a MEMs-based manipulation means, and c) electrical, electrostatic, electromagnetic, mechanical, optical, magnetic, thermo-optical, thermo-acoustic, acoustic or pressurization forces.
A microfluidic channel or film may beneficially be employed, coupled-to or part of the device itself in the case wherein the energy propagation is within a liquid.
The energy being switched, modulated, redirected or otherwise modified (or injected) may, for example, be employed to cause emission, ejection or release of droplets of a flowable material for a useful purpose such as inkjet printing of marking-inks or of biomaterials into bioarrays. The invention is not limited as to how the so-manipulated energy is beneficially employed or directed.
The device may be employed in applications such as an inkjet printer or in a product which requires emission of droplets of material in a desired temporal or spatial pattern wherein the microbubble switching action provides the temporal or spatial patterning ability. The device may also be employed in a lab-on-a-chip product wherein localized switching or manipulation of an energy or potential allows for controlled processing, analysis or storage of clinical specimens, for example.
If the energy employed in the device is RF or radiofrequency energy, it will preferably have at least one frequency component in the range of 0.1 megaHertz to 10 or more teraHertz, as is known to the electromagnetic arts.
In the device, one of more droplets, bubbles or films may be formed in an interface, the droplets, bubbles or films providing or breaking bridged contact or contacts between the interfaces such that the energy or potential can or cannot propagate across the interface.
Alternatively or additionally, the formation or destruction of one or more microbubbles, microdroplets or microfilms may be employed to form energy waveguides themselves whose function is merely (at least) to transport the energy with acceptable losses. Thus, the invention allows for the formation of waveguides and switching/modulation/redirection/injection components which can be placed along the waveguides.
Further, at least one bubble, droplet or film may have a characteristic dimension (at least a point in time) that is derived from a knowledge of a wavelength of the energy. In this manner, known resonant and anti-resonant behaviors known to those familiar with tuned circuit design can be taken advantage of.
Typically, at least one droplet, bubble or film at least one of: a) serves to switch, modulate or redirect an energy, energy component or potential energy, b) serves to inject a signal into an energy-path which may or may not already have preexisting energy in it, c) forms at least a portion of a waveguide or routing means for an energy, energy component or potential, d) has a generally spherical, hemispherical, polyhedral, ellipsoidal, body-of-revolution or elongated shape, e) forms a portion of a circuit, f) provides for a reconfigurable antenna or a former of selectively-aimed beams of the energy, or g) is an element of a phase-shifter, tunable resonator, tunable filter, delay line or capacitive switch.
In the case of the droplet, bubble or film performing the signal-injection function, then one would typically drive the bubble (or droplet volume) such that it bleeds or injects energy into the coupled energy path. A typical way of doing this would be to thermally oscillate a thermally-formed microbubble or droplet-volume of liquid or flowable material. We note that in the extreme example of this signal-injection embodiment, we can have a bubble or film of zero-dimension wherein, for example, a thermoacoustic excitation of a liquid is provided which does not involve a phase-change from liquid to vapor. We explicitly note that any energy used to form or drive our inventive microbubbles or microdroplets may be of a different type and from a different source than that being switched or modulated by the microbubble or microdroplet. So, for example, a microbubble formed by an electrical resistor could be used to switch acoustical energy.
Droplets, bubbles or films may be arranged in a pattern or wherein the bubble or droplet introducing means are arranged in a pattern. The effects of arrayed or patterned objects on radiating energy are well-known, particularly with regards to reflection and diffraction effects. This is particularly true wherein the radiating energy has a wavelength which is on-the-order-of a pitch or spacing dimension of the array or pattern or wherein the microbubbles or microdroplets themselves have a dimension which is on-the-order-of the energy wavelength. In these cases, trigonometrically-predictable wave redirection takes place.
Also in accordance with the invention, a device is provided for introducing an acoustic signal into an acoustically conductive medium. The device comprises:
In this acoustic introduction device, the droplet, bubble or film may preferably be dynamically altered or moved using thermal means to produce thermoacoustics.
Further in accordance with the present invention, a device for filtering a source of energy is provided. The device comprises:
In the filtering device, the energy to be filtered may comprise at least one of acoustic, electrical, electromagnetic, magnetic, kinetic, RF energy, or nonvisible optical energy.
In accordance with yet another aspect of the invention, a device for regulating the controlled breakup of a stream or jet of flowable material is provided. The regulating device comprises:
In the regulating device, the bubble, droplet or film may regulate a stream or jet of ink in a printing or patterning device and the stream or jet is broken or encouraged to break into ink drop portions of desired size, spacing or frequency.
In accordance with yet another aspect of the present invention, a device for the controlled selection or deselection of portions of an emitted or emitting stream or jet of flowable material is provided. The selection/deselection device comprises:
In the preferred selection/deselection device, the stream or jet is of a material to be printed or patterned upon a surface, such as an ink or a fluid utilized in a lab-on-a-chip or bioanalytical instrument. In the preferred device, the bubble or droplet doing the selection may be made up of a different material or of the same material as is being emitted. A preferred variation is wherein the bubble material is the vapor form of an emitted liquid.
In accordance with still another aspect of the present invention, an acoustic pulse modulation device is provided for modulating an emissive pressure-pulse of a droplet, stream or jet emission apparatus. The acoustic pulse modulation device comprises:
In the modulating device, the disposed bubble, droplet or film may modulate the size, frequency or velocity of one or more emitted droplets of flowable material. For example, the device may favorably tune the acoustic impedance or resonance of at least a part of the emission apparatus or emission chamber.
In accordance with another aspect of the invention, a device is provided for switching, modulating or redirecting the flow of emitted material from an orifice. The device comprises:
Also in accordance with an aspect of the invention, a device is provided for connecting or disconnecting a flow or application of a potential or flowing energy (voltage, current, temperature, charge, etc.) to a body capable of passing or further communicating that flow or potential. An electrical version of the device, for example, could comprise:
Still further in accordance with the invention, a method of locally modifying the energy-propagation properties or electrical propagation properties of a first medium with a second interposed medium is provided. The method comprises:
In the method, the energy-modifying may contribute to the handling, modulation or processing of a useful signal embodied in the energy.
In accordance with the invention, a capacitor element capable of variable capacitance is provided. The capacitor element comprises:
In the capacitor, a capacitive switch may be provided for the purpose of switching or modulating an RF, electromagnetic or magnetic signal.
Further, at least one of an RF or electromagnetic phase shifter, digital phase shifter, DTML (distributed MEMs transmission line), tunable filter, delay line, tunable resonator or reconfigurable antenna may be provided.
Also in accordance with the invention, an inkjet printer is provided, wherein the flow or motion of ink is at least one of switched, modulated or redirected by at least one disposed bubble, droplet or film of flowable material. In the inkjet printer:
Also in accordance with the invention, an inkjet printhead comprises:
Also in accordance with the invention, an inkjet printer is provided which can operate in either or both of a continuous mode or drop-on-demand mode wherein the printer comprises:
in a continuous-mode streams, jets or droplets are emitted by the CW or continuous operation of a pulser, acoustic-shock, pressure-pulse or static pressurization means;
Further in accordance with the invention, an inkjet printer is provided which utilizes a shockwave or pressure pulse to encourage or cause ink emission. The inkjet printer comprises:
Also in accordance with the present invention, a device is provided for modifying energy, an energy beam or an energy potential field comprising:
In the energy-modifying device, the beneficial energy modification may involve any one or more of refraction, diffraction, redirection, focusing effects, diffusing effects, reflection, amplitude changes, polarization or phase-change effects, while the selective microbubble/microdroplet/microfilm changing may involve one or more of:
Further in accordance with the present invention, a device is provided for modifying the ability to couple energy, the flow of energy or the passage of an energy potential between a first entity and a second entity. The device comprises:
In the modifying device, the propagation parameter is at least one of a reflection coefficient, a degree of refraction, an impedance, a conductivity, a transmissivity, a dielectric property, an RF parameter, an optical property or the height of an energy barrier.
The space can be incrementally occupied by one or more disposed droplets or bubbles of the second material or by an incrementally disposed or sized wettable film. The space may be a single space or a distributed space such as a porous or permeable region within a parent material.
The replacement of the first material with the second material may switch, modulate or redirect energy propagation or energy potential application from one or both of a) from the first entity to or upon the second entity, b) from the second entity to or upon the first entity, or c) from both entities to each other.
Software or hardware may be employed to give instructions relating to a state, parameter of, or pattern of at least one droplet, bubble or film area which are present or which are to be implemented.
The droplet, bubble or film second-material disposed in the space includes at least one of: a bubble of vapor of the first material; a bubble of a gas, air or plasma; a vacuum; a droplet or film of a formable or flowable liquid, cream, paste, gel, wax, oil, hydrocarbon-containing material, suspension, emulsion, or multiphase mixture; a material native to the first or second entity, regardless of phase; a solid, rigid or semirigid material, porous or not; a bubble, droplet or film which wets a surface; or a wetting material or a phase-changeable material such as a meltable material.
The first material in the space may include at least one of: a gas or air; a plasma; a vacuum; a droplet or film of a formable or flowable liquid, cream, paste, gel, wax, oil, hydrocarbon-containing material, suspension, emulsion, or multiphase mixture; a material native to the first or second entity, regardless of phase; a solid, rigid or semirigid material, porous or not; or a wetting material.
The disposition of the second material, at least in part, may be permanent or temporary.
The energy may include at least one of: acoustic energy, RF energy with a frequency measured in units of mehaHertz, gigaHertz or teraHertz, electromagnetic energy, optical energy, microwave energy, electrical energy as for flowable current or voltage which can be applied, thermal energy, infrared energy, kinetic or kinematic energy associated with mass-transport of a medium, any polarized or unpolarized energy, or any directional or nondirectional energy. As stated, the energy may also be in the form of an applied energy-potential rather than an energy flow.
The modified ability may include at least one of: changing the direction of passing energy; changing the ability of energy to pass; modulating passing energy in any manner; polarizing or depolarizing passing energy; filtering passing energy; adding to or impressing upon the passing energy a waveform or a new energy; changing the amount of area across which energy can pass; changing the pattern of how the area across which energy can pass is distributed; reflecting, diffracting, scattering, absorbing or attenuating some of the energy as it passes from one entity to another; controlling the reflectivity, impedance or resistance of energy flow between entities; modifying the ability in response to hardware or software sensing or computation; or converting the energy from a first form to a second form such as from RF energy to heat. Again, by energy we mean both the flow of an energy as well as the application of an energy potential.
Phenomena such as photonically induced or electrostatically induced wetting or dewetting or photonically-induced or electrostatically, electromagnetically or magnetically induced surface-tension driven shape-changes may also be utilized to manipulate or form the inventive bubbles, droplets or films. The energy, potential or work applied to manipulate or form our inventive bubbles, droplets or films will typically be of a different type than that which is being switched, redirected or modulated; however, they may alternatively be of the same type and even from the same or a similar source.
We have taught the production of acoustic waveforms and signals using our inventive droplets, bubbles and films, particularly if they are themselves driven as taught. Those familiar with acoustics will realize that the full acoustic spectrum runs from static pressure (zero hertz) all the way up to gigahertz and even terahertz. Thus, the invention can be employed to apply pseudo-static or static pressure to microfluidic lumens, for example, for technically useful time periods extending through the microsecond, millisecond, seconds and tens of seconds ranges and longer.
We have taught a means of selectively filtering a source of energy utilizing our inventive bubbles, droplets and films. Included in the scope of the filtering action is filtering that is accomplished actively or passively. By “actively”, we mean that a parameter of the bubble is varied to cause the filtering. By “passively”, we mean that even a stable bubble, droplet or film that has been so coupled can passively filter energy such as by simple acoustic or optical attenuation. We also include in the scope of the invention the selective passing or selective redirection of energy portions. In this manner, for example, a bank of frequency-dedicated or wavelength-dedicated filters can be implemented.
The present application claims priority from provisional application Ser. No. 60/536,025, filed Jan. 13, 2004.
| Number | Date | Country | |
|---|---|---|---|
| 60536025 | Jan 2004 | US |
