Abstract:
A 3-D printer scalable to large sizes employs a combination of mechanical and electrical scanning of a linear array of electron beams that operate to melt material of a powder bed. A housing holding the electron beam sources may be maintained at a high vacuum and positioned close to a print surface to minimize electron travel in a softer vacuum surrounding a print bed.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0001]    Not Applicable 
       CROSS REFERENCE TO RELATED APPLICATION 
       [0002]    Not Applicable 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to three-dimension printers and in particular to a printer using electron beams to sinter or melt layers of powder into a solid object. 
         [0004]    Three-dimension printers for implementing additive machining may create printed objects by incrementally depositing material to a print bed or previously deposited layers in a layer-by-layer fashion. A variety of different 3-D printing technologies exist. Photo polymerization techniques use lasers to polymerize a thin surface of liquid over a print bed, the latter of which is gradually withdrawn beneath the liquid surface as the object is built up. Extrusion techniques use a similar approach but extrude material such as molten plastic from a nozzle in successive layers. Powder bed systems employ a laser or electron beam to sinter or melt particles of a powder bed into a solid structure. After each layer is formed additional powder is added on top of that layer and the process repeated. 
         [0005]    Metal objects are most frequently constructed by 3-D printers using powder bed techniques with metallic powders or an approach similar to extrusion printing that uses a wire feedstock melted at its point of contact with a preceding layer. 
         [0006]    The ability to construct high-resolution, large models using 3-D printing is limited by the relatively low printing speed of each of these processes. A slow printing speed has a disproportionate effect on larger high-resolution models where printing volumes scale exponentially. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides an electron beam 3-D printer that employs a cathode-comb  26  providing multiple electron beams that may be scanned both electronically and mechanically. The cathode-comb  26  permits multiple, independent and low-cost, printing locations in parallel. By mechanically scanning the cathode-comb  26 , the cathode-comb  26  may be placed close to the print surface for improved resolution and greatly simplified electron optics. This close proximity of the print head to the print surface also permits the electrons to be accelerated in a hard vacuum with minimized travel through a soft vacuum between the print head in the print surface reducing scattering and increasing efficiency. 
         [0008]    Specifically, in one embodiment, the present invention provides a three-dimension printer having a print bed for supporting an object to be printed. A printer bar extends along a transverse axis and is supported on a printer bar carriage assembly to move longitudinally with respect to, and above, the print bed at a predetermined height above a print surface. The printer bar supports a plurality of independently controllable transversely separated electron sources for generating electron beams directed toward the print bed and an electron deflector assembly for transverse deflection of the electrons of the cathodes. A powder handling system applies powder at the print surface over the print bed and a controller communicates with the electron sources and printer bar carriage to scan the electron sources over the powder on the print bed to selectively fuse the powder at the print surface into a printed object according to a program stored in a non-transient medium. 
         [0009]    It is thus a feature of at least one embodiment of the invention to provide an architecture for a three-dimension printer that may better scale to large sizes. A cathode-comb  26  of multiple electron sources can scale with one dimension of the printed object simply by adding cathodes. 
         [0010]    The electron beams may be constrained to move substantially only in the transverse direction with respect to the printer bar. 
         [0011]    It is thus a feature of at least one embodiment of the invention to provide a control method for multiple electron beams that simplifies the electron beam optics and permits close proximity of the electron beams to the printed surface even for large printed objects. 
         [0012]    The electron deflector may provide a common deflection field across each of the electron beams to deflect the electron beams in unison. 
         [0013]    It is thus a feature of at least one embodiment of the invention to provide a scanning mechanism for multiple adjacent electron beams that eliminates possible interference if separate scanning fields were used by scanning the beams in tandem. 
         [0014]    The electron deflector may provide a magnetic field produced by at least one Helmholtz coil pair separated along a longitudinal axis. 
         [0015]    It is thus a feature of at least one embodiment of the invention to provide a simple control field that may be highly uniform and conveniently positioned along the side of rather than between the individual electron beams for improved manufacturability. 
         [0016]    The electron sources are transversely spaced by no more than one-half of a transverse range of deflection of the electron sources measured at the print surface. 
         [0017]    It is thus a feature of at least one embodiment of the invention to provide overlap between regions of the print surface accessible by each electron beam to provide improved efficiency in the printing process by selecting between different beams to print to a given area and to permit the system to continue to operate in the face of occasional cathode failure. 
         [0018]    The three-dimension printer may include a first housing holding a print bed and printer bar and a second housing within the first housing holding the electron sources of the printer bar. A first and second vacuum pumps may operate so that the second vacuum pump communicates with the second sealable airtight housing to pump gas from the second sealable airtight housing into the first sealable airtight housing, and the first vacuum pump communicates with the first sealable airtight housing to pump gas from the first sealable airtight housing to an exhaust point outside of the first sealable airtight housing. 
         [0019]    It is thus a feature of at least one embodiment of the invention to promote a hard vacuum along the majority of the flight path of the electron beams recognizing the inevitability of a soft vacuum in a large print chamber. 
         [0020]    The second housing may provide a transverse slit positioned between the electron sources and the print bed to allow passage of the electron beams throughout a transverse deflection of the electron beams and wherein the second housing is substantially sealed but for the transverse slit. 
         [0021]    It is thus a feature of at least one embodiment of the invention to provide a geometry that allows an extremely small area opening between a hard and soft vacuum such as can be managed by reverse pumping or a thin window supported on the slit. 
         [0022]    The three-dimension printer may include an electron transmissive window covering the slit. 
         [0023]    It is thus a feature of at least one embodiment of the invention to permit a low attenuation material to be placed to seal the cathodes from gas and contamination, possible because of the small slot geometry and minimized pressure differential 
         [0024]    The three-dimension printer may include a removable slit cover and nitrogen purge system for filling the second housing when the first housing is unsealed. 
         [0025]    It is thus a feature of at least one embodiment of the invention to accommodate the need to frequently open the first housing for removal of printed objects without damaging the cathodes. 
         [0026]    The controller may receive identifications of regions on the print surface for melting by an electron beam and may select among different electron beams capable of melting that region to promote parallel operation of electron beams. 
         [0027]    It is thus a feature of at least one embodiment of the invention to provide an optimization of the geometry of the present invention by leveraging the overlap between electron beams to promote parallel treatment of the printed surface. 
         [0028]    Each electron beam may be associated with an electron beam detector and the controller may operate to compensate for failure of an individual cathode by employing adjacent cathodes. 
         [0029]    It is thus a feature of at least one embodiment of the invention to provide a multiple electron beam system for large print scales that can accommodate a likelihood of cathode failures during a given print session. 
         [0030]    These particular objects and advantages may apply to only some embodiments falling within the claims and thus do not define the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0031]      FIG. 1  is a simplified perspective view of a large-scale, three-dimension printer using the cathode-comb system of the present invention such as may travel longitudinally over a powder bed; 
           [0032]      FIG. 2  is a fragmentary side elevational view of the cathode-comb closely positioned with respect to the print surface and further showing an adjacent sweeper replenishing and smoothing the powder bed; 
           [0033]      FIG. 3  is a fragmentary, front elevational block diagram of the cathode-comb  26  showing multiple independent cathodes and their associated electron optics and sweep coil and showing an overlapping of the electron beams as electronically steered by the sweep coil; 
           [0034]      FIGS. 4 a  and 4 b    are diagrammatic representations of target zones on the print surface as associated with different electron beams and showing a coordination process that maximizes parallel production of melt zones; 
           [0035]      FIG. 5  is a fragmentary perspective phantom view of the cathode-comb  26  showing a common magnetic sweeper field generated for controlling electron beams; and 
           [0036]      FIGS. 6 a  and 6 b    are top plan views of an alternative embodiment in which the sweeper and cathode-comb move in perpendicular directions with the sweeper shuttling between hoppers of powdered metal. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0037]    Referring now to  FIG. 1 , a large-scale, three-dimension printer  10  constructed according to one embodiment of the present invention may provide for a sealable housing  12  fitted with one or more access doors (not shown) and with a vacuum pump  14 . The vacuum pump  14  is sizing constructed so that the air and other gases within the housing  12  may be removed to a pressure of 10 −3  Torr to 10 −4  Torr, a level readily available with mechanical vacuum pumps. 
         [0038]    Positioned within the housing  12  to be held within the low-pressure domain is a downwardly retractable printing platform  16  presenting an upper horizontal surface that may support a powder bed  18  of finely powdered metal  19 . The printing platform  16  may be retracted or extended within the housing  12 , for example, by a distance in excess of five feet. 
         [0039]    An upper surface of the powder bed  18  presents a print surface  20  that may be subjected to selective melting at melt spots  22  where the powdered metal  19  is melted or sintered together into a fully dense solid structure. After a set of desired melt regions  22  have been formed, the printing platform  16  is lowered and a new layer of powdered metal  19  applied to the powder bed  18  raising the height of the print surface  20  above the printing platform  16  by an amount substantially equal to the depth of the melt regions  22 . New melt regions  22  are then formed of melted or fused powdered metal  19  on this new layer of particles to slowly build up a solid printed object  24  on a layer by layer basis. The powder bed  18  may also be constructed of other fusible materials including plastics, ceramics, and the like. 
         [0040]    The melt regions  22  are created by localized heating from a set of electron beams extending downward from a transversely extending cathode-comb  26  positioned above the printing platform  16 . As will be discussed in greater detail below, a housing of the cathode-comb  26  supports high vacuum pumps  29  which produce a hard vacuum within the housing of the cathode-comb  26  of greater than 10 −4  Torr. 
         [0041]    The electron beams of the cathode-comb  26  are spaced along the transverse axis and may sweep through a limited transverse angle as will be discussed below. Further, the cathode-comb  26  is mounted on longitudinal rails  28  so that it may be scanned mechanically in a longitudinal direction perpendicular to its transverse extent. In one example, the distance of scanning may exceed 15 feet. In this way the downward beams from the cathode-comb  26  may be directed either by mechanical or electrical scanning to expose any spot within a continuous printing region of the print surface  20 . A variety of techniques may be used to implement the mechanical portion of the scanning including, for example, longitudinal lead screws extending along the longitudinal rails  28  and received by corresponding threaded elements on the cathode-comb  26  and driven by servo or stepper motors or the like. 
         [0042]    The three-dimension printer  10  may include an electronic computer  30  having one or more processors  32  and electronic memory  34  for storing, in non-transient form, a control program and data necessary for the construction of the printed object  24 . Electronic computer  30  may communicate with and control various aspects of the three-dimension printer  10  discussed above and as will be discussed below including drive motor systems  40  for moving the cathode-comb  26  along the rails  28  and elevation systems  42  (hydraulics or mechanical lead screws or the like) for elevating the print platform to control positions. 
         [0043]    The three-dimension printer  10  may also provide a power supply controllable by the computer  30  to provide power to the various mechanical elements discussed above and the circuitry of the cathode-comb  26  as will be discussed below. The electronic computer  30  and a power supply  36  may communicate over flexible conductors  38  with the cathode-comb  26  throughout its range of motion. 
         [0044]    Referring now to  FIG. 2  the cathode-comb  26  may provide a housing  45  providing an internal volume  44  held at a high vacuum of 10 −4  Torr or greater provided by the high vacuum pumps  29  shown in  FIG. 1 . Inside the housing  45  a set of cathodes  60  emit beams  48  of electrons directed downward toward the print surface  20 . The beams  48  will travel for the majority of their path from the cathode to the print surface  20  within the hard vacuum of volume  44  and then exit the housing  45  to travel through the softer vacuum of housing  12 . Desirably this latter distance is minimized. 
         [0045]    A source of nitrogen gas  50  may communicate with the volume  44  to fill a volume  44  when the housing  12  is open to the atmosphere to prevent oxygen poisoning of the material of the cathode  60 . In embodiments where the electron beam  48  passes through an opening in the housing  45  of the cathode-comb  26 , a sealing door  52  may be moved into place over that opening during such times. 
         [0046]    Referring still to  FIG. 2 , rails  28  along which the cathode-comb  26  may move may be shared by one or more sweepers  54  communicating with a reservoir  56  of powdered metal  19 . The sweeper  54  may include a hollow transverse bar  57  providing an internal conveyor or the like for the distribution of powdered metal  19  over the transverse dimension of the print surface  20  by means of the conveyor and over the longitudinal dimension of the print surface  20  by movement of the sweeper  54  on the rails  28  under control a computer  30 . In this respect, the sweepers  54  may share the drive system of the rails  28  moving the cathode-comb  26  or may employ their own drive system. The distribution of powdered metal  19  between each printing layer as is generally known in the art may be conducted concurrently with the printing process. Print surface preheaters  58  may be attached to the bar  57  to preheat the surface  20  minimizing the amount of heat that needs to be deposited by the electron beam  48  to produce melt spots. A second similar sweeper  54  (not shown) may be placed on the opposite side of the cathode-comb  26  to distribute powdered metal  19  in bidirectional printing, or separate longitudinal rails  28  may be used to allow a single sweeper  54  to pass beneath the cathode-comb  26  upon direction reversals in the longitudinal axis. 
         [0047]    Referring now to  FIGS. 6 a  and 6 b   , in an alternative embodiment, the sweeper  54  may be mounted to move perpendicularly to the cathode-comb  26  between longitudinally extending hoppers  84  of powdered metal  19  placed on opposite transverse sides of the powder bed  18 . Between each longitudinal pass of the cathode comb  26 , indicated by arrow  86 , the sweeper  54  may shuttle between one reservoir  84  and the other to deposit a thin layer of powdered metal  19  over the powder bed  18  as indicated by arrow  88 . During the movement of the cathode-comb  26 , the sweeper  54  is parked against one of the hoppers  84  and an internal reservoir of the sweeper  54  may be recharged from that adjacent hopper  84 . 
         [0048]    Referring now to  FIGS. 3 and 5 , the volume  44  of the cathode-comb  26  supports a set of regularly, transversely spaced cathodes  60  at a spacing distance  59 . In one embodiment the invention contemplates more than 10 cathodes; however, generally the number of cathodes will be selected to span the transverse dimension of the print surface  20  to provide a desired degree of beam overlap for a given angular sweep range of the beams and the distance between the cathode-comb  26  and the print surface, as will be discussed generally below. 
         [0049]    Each cathode  60  may be, for example, a thermionic material such as lanthanum hexaboride, tungsten carbide, or dispenser cathode heated by ohmic heating of current passing through the cathode  60  generated by a cathode power supply  67  controllable by the computer  30 . Alternatively, the cathode  60  may be heated by radiant heat from a separate heater element. In one embodiment, each cathode  60  may provide a wire form into a downwardly directed chevron to provide at a lower apex to a concentrated point of electron emissions to generate a tightly focused electron beam. 
         [0050]    As is generally understood in the art, the cathode  60  may be surrounded by a Wehnelt cylinder  62  or the like biased to a negative voltage with respect to the cathode  60  (for example, −200 volts) to create a repulsive electrostatic field that directs the electron  61  in a beam  48  from the cathode  60  downward toward an anode  64  typically at a large positive voltage in the tens of kilovolts relative to the cathode  60  to strongly attract the electrons from the cathode  60 . In practice, the anode  64  and the powder bed  18  are grounded for simplicity and safety and the relatively high positive voltage of the anode  64  with respect to the cathode  60  is obtained by operating the cathode  60  at a large negative voltage with respect to ground. The anode  64  may have a central opening  65  through which the electron beam  48  is accelerated. Electrons  61  of the beam  48  are then received by electron optics  66  such as focusing magnetic or electrostatic lenses of a type known in the art. Voltage sources to each of the Wehnelt cylinder  62 , anode  64 , and electron optics  66  may be computer-controlled. In particular the voltage on the Wehnelt cylinder  62  (or on a separate grid structure) may be controlled to switch the electron beam  48  of electrons  61  on or off as desired by the computer. An electron beam sensor  71  may confirm operation of the electron beam, for example, detecting magnetic fields associate with the passage of the electrons by detecting a corresponding magnetic field or by other techniques understood in the art. The sensor  71  may communicate with the computer  30  which may monitor the generation of electrons  61  in a beam  48 . 
         [0051]    The downwardly extending electron beam  48  is next received in a magnetic field region  68  provided by longitudinally opposed coils of a Helmholtz coil pair  70 . The magnetic field is generally directed along the longitudinal axis to deflect the electron beam  48  within a vertical transversely extending plane at any angle within a steering angular range  72 . Generally, the steering angular range  72  may be relatively small because of the architecture of the present invention and will normally be an angular range of less than 90 degrees and preferably less than 60 degrees to simplify the electron optics and reduce aberration and loss of printing resolution. 
         [0052]    Generally, each coil of the Helmholtz coil pair  70  is spaced on either side of a vertical plane holding the cathode  60 . Current passes through each coil of the Helmholtz coil pair  70  in the same direction (clockwise or counterclockwise) to produce a highly uniform longitudinal magnetic field  63  whose amplitude and polarity may be changed by changing the current flow through the Helmholtz coil pair  70  in unison by the computer  30 . Desirably, the Helmholtz coil pair  70  will have a low inductance to be quickly switched for rapid steering of the electron beams  48 . 
         [0053]    The spacing of the cathodes  60  and the field strength of the Helmholtz coil pair  70  are selected to provide small angular ranges  72  that nevertheless provide a coverage region  74  for each electron beam along a transverse line on the print surface  20  of approximately twice the transverse spacing  59  of the cathode  60 . In this way, adjacent electron beams  48  overlap so that a given point on the print surface  20  may be treated by either of two different electron beams  48  associate with different cathodes  60 . 
         [0054]    The electron beams  48 , as steered by the Helmholtz coil pair  70 , then pass through one or more aligned transversely extending slits  75 . The slits  75  have a longitudinal width substantially equal to the narrow width of the electron beam  48  and thus provide a relatively low total area opening minimizing gas leakage therethrough. In one embodiment, two vertically aligned transversely extending slits  75   a  and  75   b  will be provided creating a gas baffle as will be described below. The entire path length between the cathodes  60  and the final slit  75   b  will be considered to be within the volume  44  of the housing  45 . 
         [0055]    Generally, one or more vacuum pumps  29  may be configured to pump gas from the housing  45  having a relatively hard vacuum into the softer vacuum of the housing  12 . For example, when two slits  75  are used in a baffle configuration, a first vacuum pump  29   a  pumps gas from a space between the slits  75   a  and  75   b  to the housing  12  and a second vacuum pump  29   b  pumps gas from a volume  44  above the slits  75   a  into the space between the slits  75   a  and  75   b.    
         [0056]    Despite gas  76  leaking backward through the slits  75 , the pumps  29  may preserve a low-pressure of approximately 10 −4  Torr in the region of acceleration of the electron beam and for the majority of a path of the electron beam  48  toward the surface  20  while permitting the higher pressure in the housing  12  consistent with the need to maintain a vacuum in a larger volume with the inevitable outgassing of materials under heating. Generally, the amount of distance  78  traveled by the electron beam past the second slit  75   b  through the soft vacuum of the housing  12  will be reduced to the extent possible and may be, for example, less than six inches. The total path length from the cathodes  60  to the print surface  20  will typically be less than two feet. 
         [0057]    The gas streams through the pumps  29  may be cooled by an intercooler fed by chilled water (not shown). The upper pump  29   b  may be, for example, a turbo pump operating at less than 10 −4  Torr, for example, commercially available from Varian, Inc. having offices in Lexington, Mass. The lower pump  29   a  may be a roots blower, for example, of a type commercially available from Leybold Vacuum Products, Inc. having offices in Export, Pennsylvania. 
         [0058]    Outside of the slits  75 , the housing  45  is generally sealed. While it is contemplated that the slits  75  will be open to allow gas passage between the housing  45  and the housing  12 , it will be appreciated that the low pressure differential across the slits provided by the present pumping system and the narrow size of the slits permits a thin window to be placed over the slits preventing gas exchange, for example, composed of a low electron scattering material such as beryllium or graphene. 
         [0059]    Referring to  FIG. 3 , printing platform  16  may include a set of internal channels  80  allowing for the passage of cooled fluid such as gases or liquids as circulated by pumps (not shown) to help remove heat from the printed object  24  and the surrounding powder bed  18 . 
         [0060]    Referring now to  FIG. 4 a   , the electron beams  48  from successive cathodes  60  at a given longitudinal position of the cathode-comb  26  define successive transversely spaced and overlapping treatment zones  82   a - d . For clarity in  FIG. 4 , alternate treatment zones are offset downward so that they don&#39;t overlap. For a given longitudinal position of the cathode-comb  26 , it may be desired to produce two melt spots  22  (designated A and B) that are within the range of either of two electron beams from different cathodes  60 . For example, melt spot  22  (designated A) can be treated from a beam associated with zone  82   a  or beam associated with zone  82   b . Likewise, melt spot  22  (designated B) can be treated by a beam associated with zone  82   b  or zone  82   c . This leads to at least two different options for creating any given melt spot  22  and a large variety of different options for multiple given melt regions  22 . 
         [0061]    The computer  30  executing a stored program and working on data indicating desired locations of melt spots  22  may select between different cathodes  60  that may be used for any given melt spot  22  in order to increase parallel processing of the melt spots  22 . For example, referring to  FIG. 4 b    which depicts zones  82  aligned according to equal angle of beam deflection, it can be seen that two different beam deflection angles can be used to allow simultaneous creation of melt spots  22  for regions A and B using different cathodes  60 . That is, regions A and B can be simultaneously treated (that is, without changing the beam angle) using the electron beams  48  of zone  82   a  and zone  82   b , or alternatively using the electron beams  48  of zone  82   b  and zone  82   c . This should be compared, for example, to using the electron beams  48  associated with zone  82   a  for treatment region A and the electron beam  48  associated with zone  82   c  for treatment region B which does not permit the simultaneous treatment by two different cathodes and thus timesaving option of parallel melting. Generally the selection of which cathode  60  will treat which treatment region (e.g. A or B) may consider not only process speed but also minimizing warping from thermal stress. This latter goal endeavors to maintain a more constant temperature at the treatment regions. 
         [0062]    It will be appreciated that these considerations may create complex trade-offs among many additional melt spots  22  spread among many additional zones  82 . This optimization process of maximizing parallel melt spot  22  generation and reducing thermal stress may be implemented by the computer  30 , for example, using any one of a number of optimization techniques for minimizing printing time including gradient descent techniques or simulated annealing and the like which tied various assignments of different melt spots  22  to different cathodes  60  and their zones  82  to minimize the total required printing time. 
         [0063]    Computer  30  may also monitor and react to cathode failure detected through sensor  71  to allow the adjacent electron beams  48  from adjacent cathodes  60  to fill in for a damaged or inoperative cathode  60 . Such cathode failure may promote a recalculation of optimal beam positioning to produce a set of predetermined melt spots  22 . 
         [0064]    Generally, prior to the printing process, a three-dimensional model of the printed object  24  (shown in  FIG. 1 ) may be generated using standard computer aided design (CAD) tools or a three-dimensional scanner. The model is then divided into a set of layers using “slicer” programs known in the art, such as Skeinforge. This process produces a set of melt zone areas for each layer, for example, as may be expressed in a control code for the three-dimension printer  10 , for example, using a G-code formulation. This G code formulation is then optimized using the techniques discussed with respect to  FIG. 4 . 
         [0065]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0066]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0067]    References to a processor can be understood to include one or more processors that can communicate in a stand-alone and/or a distributed environment(s), and can thus be configured to communicate via wired or wireless communications with other processors, where such one or more processor can be configured to operate on one or more processor-controlled devices that can be similar or different devices. Furthermore, references to memory, unless otherwise specified, can include one or more processor-readable and accessible memory elements and/or components that can be internal to the processor-controlled device, external to the processor-controlled device, and can be accessed via a wired or wireless network. 
         [0068]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.