Abstract:
A system of electronically active inks is described which may include electronically addressable contrast media, conductors, insulators, resistors, semiconductive materials, magnetic materials, spin materials, piezoelectric materials, optoelectronic, thermoelectric or radio frequency materials. We further describe a printing system capable of laying down said materials in a definite pattern. Such a system may be used for instance to: print a flat panel display complete with onboard drive logic; print a working logic circuit onto any of a large class of substrates; print an electrostatic or piezoelectric motor with onboard logic and feedback or print a working radio transmitter or receiver.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of copending application Ser. No. 10/652,218, filed Aug. 29, 2003, which is a continuation of U.S. Ser. No. 10/200,571, filed Jul. 22, 2002 (now U.S. Pat. No. 6,652,075), which is a continuation of U.S. Ser. No. 09/471,604, filed Dec. 23, 1999 (now U.S. Pat. No. 6,422,687), which is a divisional of U.S. Ser. No. 08/935,800, filed Sep. 23, 1997 (now U.S. Pat. No. 6,120,588), which claims priority to U.S. Provisional Application No. 60/035,622, filed Sep. 24, 1996, and claims priority to and is a continuation-in-part of International Application PCT/US96/13469, filed Aug. 20, 1996, which claims priority to U.S. Provisional Application No. 60/022,222, filed Jul. 19, 1996, the entire disclosures of which applications are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF INVENTION 
     Currently, printing of conductors and resistors is well known in the art of circuit board manufacture. In order to incorporate logic elements the standard practice is to surface mount semiconductor chips onto said circuit board. To date there does not exist a system for directly printing said logic elements onto an arbitrary substrate. 
     In the area of flat panel display drivers there exists technology for laying down logic elements onto glass by means of vacuum depositing silicon or other semiconductive material and subsequently etching circuits and logic elements. Such a technology is not amenable to laying down logic elements onto an arbitrary surface due to the presence of the vacuum requirement and the etch step. 
     In the area of electronically addressable contrast media (as may be used to effect a flat panel display) emissive and reflective electronically active films (such as electroluminescent and electrochromic films), polymer dispersed liquid crystal films, and bichromal microsphere elastomeric slabs are known. No such directly electronically addressable contrast medium however is amenable to printing onto an arbitrary surface. 
     Finally in the area of surface actuators electrostatic motors, which may be etched or non-etched, are known in the art. In the first case, such etched devices suffer from their inability to be fabricated on arbitrary surfaces. In the second case, non-etched devices suffer from the inability to incorporate drive logic and electronic control directly onto the actuating surface. 
     It is an object of the present disclosure to overcome the limitations of the prior art in the area of printable logic, display and actuation. 
     SUMMARY OF THE INVENTION 
     In general the present invention provides a system of electronically active inks and means for printing said inks in an arbitrary pattern onto a large class of substrates without the requirements of standard vacuum processing or etching. Said inks may incorporate mechanical, electrical or other properties and may provide but are not limited to the following function: conducting, insulating, resistive, magnetic, semiconductive, light modulating, piezoelectric, spin, optoelectronic, thermoelectric or radio frequency. 
     In one embodiment this invention provides for a microencapsulated electric field actuated contrast ink system suitable for addressing by means of top and bottom electrodes or solely bottom electrodes and which operates by means of a bichromal dipolar microsphere, electrophoretic, dye system, liquid crystal, electroluminescent dye system or dielectrophoretic effect. Such an ink system may be useful in fabricating an electronically addressable display on any of a large class of substrate materials which may be thin, flexible and may result in an inexpensive display. 
     In another embodiment this invention provides for a semiconductive ink system in which a semiconductor material is deployed in a binder such that when said binder is cured a percolated structure with semiconductive properties results. 
     In another embodiment this invention for provides for systems capable of printing an arbitrary pattern of metal or semiconductive materials by means of photoreduction of a salt, electron beam reduction of a salt, jet electroplating, dual jet electroless plating or inert gas or local vacuum thermal, sputtering or electron beam deposition. 
     In another embodiment this invention provides for semiconductor logic elements and electro-optical elements which may include diode, transistor, light emitting, light sensing or solar cell elements which are fabricated by means of a printing process or which employ an electronically active ink system as described in the aforementioned embodiments. Additionally said elements may be multilayered and may form multilayer logic including vias and three dimensional interconnects. 
     In another embodiment this invention provides for analog circuits elements which may include resistors, capacitors, inductors or elements which may be used in radio applications or magnetic or electric field transmission of power or data. 
     In another embodiment this invention provides for an electronically addressable display in which some or all of address lines, electronically addressable contrast media, logic or power are fabricated by means of a printing process or which employ an electronically active ink system as described in the aforementioned embodiments. Such display may further comprise a radio receiver or transceiver and power means thus forming a display sheet capable of receiving wireless data and displaying the same. 
     In another embodiment this invention provides for an electrostatic actuator or motor which may be in the form of a clock or watch in which some or all of address lines, logic or power are fabricated by means of a printing process or which employ an electronically active ink system as described in the aforementioned embodiments. 
     In another embodiment this invention provides for a wrist watch band which includes an electronically addressable display in which some or all of address lines, electronically addressable contrast media, logic or power are fabricated by means of a printing process or which employ an electronically active ink system as described in the aforementioned embodiments. Said watch band may be formed such that it has no external connections but rather receives data and or power by means of electric or magnetic field flux coupling by means of an antennae which may be a printed antennae. 
     In another embodiment this invention provides for a spin computer in which some or all of address lines, electronically addressable spin media, logic or power are fabricated by means of a printing process or which employ an electronically active ink system as described in the aforementioned embodiments. 
     Further features and aspects will become apparent from the following description and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
         FIGS. 1A-F  are schematic representations of means of fabricating particles with a permanent dipole moment. 
         FIGS. 2A-C  are schematic representations of means of microencapsulation. 
         FIGS. 3A-E  are schematic representations of microencapsulated electronically addressable contrast media systems suitable for top to bottom addressing. 
         FIGS. 4A-M  are schematic representations of microencapsulated electronically addressable contrast media systems suitable for bottom addressing. 
         FIGS. 5A-D  are schematic representations of microencapsulated electronically addressable contrast media systems based on a dielectrophoretic effect. 
         FIGS. 6A-B  are schematic representations of microencapsulated electronically addressable contrast media systems based on a frequency dependent dielectrophoretic effect. 
         FIGS. 6C-E  are plots of the dielectric parameter as a function of frequency for various physical systems. 
         FIGS. 7A-D  are schematic representations of electronic ink systems and means for printing the same. 
         FIG. 8  is a schematic representation of a laser reduced metal salt ink system. 
         FIGS. 9A-E  are schematic representations of electronic ink systems and means for printing the same. 
         FIGS. 10A-C  are schematic diagrams of printed transistor structures. 
         FIG. 10D  is a schematic diagram of a printed optoelectronic element. 
         FIGS. 10E-H  are schematic diagrams of printed analog circuit elements. 
         FIGS. 11A-C  are a schematic diagram of an electronic display employing printed elements which; this display may further include a data receiver or transceiver and a power means. 
         FIG. 12  is a schematic diagram of an electrostatic motor which may be in the form of a watch or clock in which said electrostatic elements are printed. 
         FIGS. 13A-B  are a schematic diagram of a watch in which the wristband of said watch incorporates an electronically addressable display having printed elements and which may further comprise wireless means for sending or receiving data or power between watch and watchband. 
         FIG. 14  is a schematic diagram of a spin computer. 
     
    
    
     DETAILED DESCRIPTION 
     Means are known in the prior art for producing bichromal particles or microspheres for use in electronic displays. Such techniques produce a particle that does not have an implanted dipole moment but rather relies in general on the Zeta potential of the material to create a permanent dipole. Such a scheme suffers from the fact that it links the material properties to the electronic properties thus limiting the size of the dipole moment which may be created.  FIG. 1  details means of producing particles, either bichromal as might be used in an electrostatic display, or monochromal as might be used in a dielectrophoretic display, with an implanted dipole moment. 
     Referring to  FIG. 1A , atomizing nozzles  1  are loaded with materials  12  and  13  which may be differently colored. A first atomizing nozzle may be held at a positive potential  3  and a second nozzle may be held at a negative potential  4 . Such potentials aid in atomization and impart a charge to droplets which form from said nozzles producing positively charged droplets  5  and negatively charged droplets  6 . Such opposite charged droplets are attracted to each other electrostatically forming an overall neutral pair. After the formation of a neutral pair there is no more electrostatic attraction and no additional droplets are attracted to the neutral pair. If said material  12  and  13  is such that the particles are liquid when exiting said nozzles and either cool to form a solid or undergo a chemical reaction which may involve an additional hardening agent to form a solid then said charge may be trapped on each side of said neutral pair forming a bichromal solid particle with an implanted dipole  16 . By suitable choice of materials such as polyethylene, polyvinylidene fluoride or other materials such metastable dipoles may persist for long periods of time as is known in the art of electrets. A heating element  7  may serve to reheat said pair thus minimizing surface tension energy and serving to reform said pair into a more perfect spherical shape. Finally a set of electrodes  8  biased at either the same or opposite voltage may be employed to trap particles which are not overall charge neutral. 
     Referring to  FIG. 1B  a similar apparatus may be employed to create a monochromal particle with an implanted dipole. In this arrangement nozzles containing material of the same color  12  are employed as before to create a monochromal particle with implanted dipole  21 . 
     Referring to  FIGS. 1C and 1D  alternative means are shown for producing a bichromal particle with implanted dipole by means of combining two differentially colored materials  12  and  13  on a spinning disk  11  or in a double barreled nozzle  19 . Said materials are charged by means of positive electrode  14  and negative electrode  15  and combine by means of electrostatic attraction at the rim of said disk or exit of said double barrel nozzle to form bichromal particle with implanted dipole moment  16 . Said means differs from that known in the art by means of causing said two different materials  12  and  13  to coalesce by means of electrostatic attraction as opposed to relying on surface properties and interactions between the two materials. Additionally the present scheme creates a particle with an implanted dipole moment  16  which may serve to create a larger dipole moment than that possible from the naturally occurring Zeta potential. 
     Referring to  FIGS. 1E and 1F , a similar apparatus may be employed to create a monochromal particle with an implanted dipole. In this arrangement nozzles containing material of the same color  12  are employed as before to create a monochromal particle with implanted dipole  21 . 
     A large number of techniques are known in the literature for microencapsulating one material inside of another material. Such techniques are generally used in the paper or pharmaceutical industry and do not generally produce a microcapsule which embodies simultaneously the properties of optical clarity, high dielectric strength, impermeability and resistance to pressure. With proper modification however these techniques may be made amenable to microencapsulating systems with electronic properties. 
     Referring to  FIG. 2A , an internal phase  25  may be a liquid or may be a solid with an additional associated surface layer  27 . Said internal phase if liquid or said associated surface layer may contain a polymer building block, such as adipoyl chloride in silicone oil. Said internal phase, with associated boundary layer in the case of a liquid, may then be dispersed in a continuous phase liquid  30  which may be an aqueous solution which is immiscible with said internal phase or associated surface layer. Finally a solution  40  which contains another polymer building block or cross linking agent may be added to continuous phase liquid  30 . Said solution  40  has the effect of forming a solid layer at the interface of the internal phase or associated surface layer and said continuous phase liquid  30  thus acting to microencapsulate said internal phase. 
     Referring to  FIG. 2B  an internal phase  25  which may be a solid or a liquid may be caused to pass through a series of liquid films  50 , 60 , 70  which may contain polymer building blocks, cross linking agents and overcoat materials such that a final microcapsule  120  results comprised of an internal phase  25 , an associated surface layer  27  and an outer shell  80 . 
     An alternate means of microencapsulation is shown in  FIG. 2C . In this scheme a light source  82  which may be a UV light source passes in some areas through a photomask  84  exposing a crosslinkable polymer which may be caused to form a cellular structure  86 . The individual cells of said cellular structure may then be filled with an internal phase  25 . 
     Employing the systems described in  FIGS. 2A-C  it is possible to microencapsulate systems with electronically active properties specifically electronically addressable contrast media.  FIG. 3  details such electronically addressable contrast media systems which are suitable for addressing by means of a top clear electrode  100  and bottom electrode  110 . Referring to  FIG. 3A  a microcapsule  120  may contain a microsphere with a positively charged hemisphere  142  and a negatively charged  140  hemisphere and an associated surface layer material  130 . If said hemispheres are differentially colored an electric field applied to said electrodes may act to change the orientation of said sphere thus causing a perceived change in color. 
     Referring to  FIG. 3B  a microcapsule  120  may contain positively charged particles of one color  210  and negatively charged particles of another color  220  such that application of an electric field to said electrodes causes a migration of the one color or the other color, depending on the polarity of the field, toward the surface of said microcapsule and thus effecting a perceived color change. Such a system constitutes a microencapsulated electrophoretic system. 
     Referring to  FIGS. 3C-D , a microcapsule  120  may contain a dye, dye precursor or dye indicator material of a given charge polarity  230  or a dye, dye precursor or dye indicator material attached to a particle of given charge polarity such as a microsphere with an appropriate surface group attached and a reducing, oxidizing, proton donating, proton absorbing or solvent agent of the other charge polarity  240  or a reducing, oxidizing, proton donating, proton absorbing or solvent agent attached to a particle of the other charge polarity. Under application of an electric field said dye substance  230  is maintained distal to said reducing, oxidizing, proton donating, proton absorbing or solvent agent  240  thus effecting one color state as in  FIG. 3C . Upon de-application of said electric field said dye substance and said reducing, oxidizing, proton donating, proton absorbing or solvent agent may bond to form a complex  245  of second color state. Suitable materials for use in this system are leuco and lactone dye systems and other ring structures which may go from a state of one color to a state of a second color upon application of a reducing, oxidizing or solvent agent or dye indicator systems which may go from a state of one color to a state of a second color upon application of a proton donating or proton absorbing agent as is known in the art. An additional gel or polymer material may be added to the contents of said microcapsule in order to effect a bistability of the system such that said constituents are relatively immobile except on application of an electric field. 
     Referring to  FIG. 3E , a microcapsule  120  may contain phosphor particles  255  and photoconductive semiconductor particles and dye indicator particles  260  in a suitable binder  250 . Applying an AC electric field to electrodes  100  and  110  causes AC electroluminescence which causes free charge to be generated in the semiconducting material further causing said dye indicator to change color state. 
     Referring to  FIGS. 4A-M , it may be desirable to develop ink systems which are suitable for use without a top transparent electrode  100  which may degrade the optical characteristics of the device. Referring to  FIGS. 4A and 4B , the chemistry as described in reference to  FIGS. 3C-D  may be employed with in-plane electrodes such that said chemistry undergoes a color switch from one color state to a second color state upon application of an electric field to in-plane electrodes  270  and  280 . Such a system is viewed from above and thus said electrodes may be opaque and do not effect the optical characteristics of said display. 
     As another system in-plane switching techniques have been employed in transmissive LCD displays for another purpose, namely to increase viewing angle of such displays. Referring to  FIGS. 4C and 4D  a bistable liquid crystal system of the type demonstrated by Hatano et. al. of Minolta Corp. is modified to be effected by in plane electrodes such that a liquid crystal mixture transforms from a first transparent planar structure  290  to a second scattering focal conic structure  292 . 
     Referring to  FIG. 4E  the system of  FIG. 3E  may be switched by use of in-plane electrodes  270  and  280 . 
     Other systems may be created which cause a first color change by means of applying an AC field and a second color change by means of application of either a DC field or an AC field of another frequency. Referring to  FIGS. 4F-G , a hairpin shaped molecule or spring in the closed state  284  may have attached to it a positively charged  282  and a negatively charged  283  head which may be microspheres with implanted dipoles. Additionally one side of said hairpin shaped molecule or spring has attached to it a leuco dye  286  and the other side of said hairpin shaped molecule or spring has attached to it a reducing agent  285 . When said molecule or spring is in the closed state  284  then said leuco dye  286  and said reducing agent  285  are brought into proximity such that a bond is formed  287  and said leuco dye is effectively reduced thus effecting a first color state. Upon a applying an AC electric field with frequency that is resonant with the vibrational mode of said charged heads cantilevered on said hairpin shaped molecule or spring said bond  287  may be made to break, thus yielding an open state  288 . In said open state the leuco dye and reducing agent are no longer proximal and the leuco dye, being in a non-reduced state, effects a second color state. The system may be reversed by applying a DC electric field which serves to reproximate the leuco dye and reducing agent groups. Many molecules or microfabricated structures may serve as the normally open hairpin shaped molecule or spring. These may include oleic acid like molecules  289 . Reducing agents may include sodium dithionite. The system as discussed is bistable. Energy may be stored in said hairpin shaped molecule or spring and as such said system may also function as a battery. 
     Referring to  FIGS. 4I-K  an alternative leucodye-reducing agent system may employ a polymer shown in  FIG. 4I  in a natural state  293 . When a DC electric field is applied said polymer assumes a linear shape  294  with leuco  286  and reducing agent  285  groups distal from each other. Upon application of either a reversing DC field or an AC electric field said polymer will tend to coil bringing into random contact said leuco and reducing groups forming a bond  287  with a corresponding color change. Said polymer serves to make said system bistable. 
     Referring to  FIGS. 4L and 4M , a similar system is possible but instead polymer leuco and reducing groups may be attached to oppositely charge microspheres directly by means of a bridge  286  which may be a biotin-streptavidin bridge, polymer bridge or any other suitable bridge. As before application of a DC field cause leuco and reducing groups to become distal whereas application of a reverse DC field or AC field brings into random contact the leuco and reducing groups. A polymer may be added to aid in the stability of the oxidized state. 
     Referring to  FIGS. 5A-D  and  FIGS. 6A-B  an entirely different principle may be employed in an electronically addressable contrast media ink. In these systems the dielectrophoretic effect is employed in which a species of higher dielectric constant may be caused to move to a region of high electric field strength. 
     Referring to  FIGS. 5A and 5B  a non-colored dye solvent complex  315  which is stable when no field is applied across electrode pair  150  may be caused to become dissociate into colored dye  300  and solvent  310  components by means of an electric field  170  acting differentially on the dielectric constant of said dye complex and said solvent complex as applied by electrode pair  150 . It is understood that the chemistries as discussed in the system of  FIG. 3C-D  may readily be employed here and that said dye complex and said solvent complex need not themselves have substantially different dielectric constants but rather may be associated with other molecules or particles such as microspheres with substantially different dielectric constants. Finally it is understood that a gel or polymer complex may be added to the contents of said microcapsule in order to effect a bistability. 
     Referring to  FIG. 5C-D  stacked electrode pairs  150  and  160  may be employed to effect a high electric field region in a higher  170  or lower  180  plane thus causing a higher dielectric constant material such as one hemisphere of a bichromal microsphere  141  or one species of a mixture of colored species  147  to migrate to a higher or lower plane respectively and give the effect of differing color states. In such schemes materials  165  which may be dielectric materials or may be conducting materials may be employed to shape said electric fields. 
     Referring to  FIGS. 6A-B , systems based on a frequency dependent dielectrophoretic effect are described. Such systems are addressed by means of applying a field of one frequency to produce a given color and applying a field of a different frequency to produce another color. Such a functionality allows for a rear addressed display. 
     Referring to  FIG. 6A , a microcapsule  120  encompasses an internal phase  184  which may be a material which has a frequency independent dielectric constant as shown in  FIG. 6C , curve  320  and which may have a first color B and material  182  which has a frequency dependent dielectric constant and a second color W. Said frequency dependent material may further have a high dielectric constant at low frequency and a smaller dielectric constant at higher frequency as shown in  FIG. 6C , curve  322 . Application of a low frequency AC field by means of electrodes  270  and  280  causes said material  182  to be attracted to the high field region proximal the electrodes thus causing said microcapsule to appear as the color B when viewed from above. Conversely application of a high frequency AC field by means of electrodes  270  and  280  causes said material  184  to be attracted to the high field region proximal the electrodes thus displacing material  182  and thus causing said microcapsule to appear as the color W when viewed from above. If B and W correspond to Black and White then a black and white display may be effected. A polymer material may be added to internal phase  184  to cause said system to be bistable in the field off condition. Alternatively stiction to the internal side wall of said capsule may cause bistability. 
     Referring to  FIG. 6A , material  182  and  FIG. 6C , a particle is fabricated with an engineered frequency dependent dielectric constant. The means for fabricating this particle are depicted in  FIGS. 1B , E and F. At low frequency such dipolar particles have sufficiently small mass that they may rotate in phase with said AC field thus effectively canceling said field and acting as a high dielectric constant material. At high frequency however the inertia of said particles is such that they cannot keep in phase with said AC field and thus fail to cancel said field and consequently have an effectively small dielectric constant. 
     Alternatively material  182  may be comprised of naturally occurring frequency dependent dielectric materials. Materials which obey a frequency dependence functionality similar to the artificially created dipole material discussed above and which follow curves similar to  FIG. 6C , curve  322  include materials such as Hevea rubber compound which has a dielectric constant of K=36 at f=10 3  Hz and K=9 at f=10 6  Hz, materials with ohmic loss as are known in Electromechanics of Particles by T. B. Jones incorporated herein by reference and macromolecules with permanent dipole moments. 
     Additionally material  182  may be a natural or artificial cell material which has a dielectric constant frequency dependence as depicted in  FIG. 6D , curve  330  as are discussed in Electromechanics of Particles by T. B. Jones incorporated herein by reference. Such particles are further suitable for fabrication of an electronically addressable contrast ink. 
     Referring to  FIG. 6B , a system is depicted capable of effecting a color display. Microcapsule  120  contains a particle of a first dielectric constant, conductivity and color  186 , a particle of a second dielectric constant, conductivity and color and an internal phase of a third dielectric constant, conductivity and color  190 . Referring to  FIG. 6E  it is known in the art of electromechanics of particles that for particles with ohmic loss (e.g. finite conductivity) at low frequency the DC conductivity governs the dielectric constant whereas at high frequency the dielectric polarization governs the dielectric constant. Thus a particle with finite conductivity has a dielectric constant K as a function of frequency f as in  FIG. 6E , curve  338 . A second particle of second color has a dielectric constant K as a function of frequency f as in  FIG. 6E , curve  340 . Finally an internal phase with no conductivity has a frequency independent dielectric constant K, curve  336 . If an AC field of frequency f 1  is applied by means of electrodes  270  and  280 , material  186  of color M will be attracted to the high field region proximal to said electrodes thus causing said microcapsule to appear as a mixture of the colors C and Y, due to the other particle and internal phase respectively, when viewed from above. If an AC field of frequency f 2  is applied by means of electrodes  270  and  280  material  188  of color Y will be attracted to the high field region proximal to said electrodes thus causing said microcapsule to appear as a mixture of the colors C and M when viewed from above. Finally if an AC field of frequency f 3  is applied by means of electrodes  270  and  280  internal phase  190  of color C will be attracted to the high field region proximal to said electrodes thus causing said microcapsule to appear as a mixture of the colors M and Y when viewed from above. If C, M and Y correspond to Cyan, Magenta and Yellow a color display may be effected. 
     It is understood that many other combinations of particles with frequency dependent dielectric constants arising from the physical processes discussed above may be employed to effect a frequency dependent electronically addressable display. 
     In addition to the microencapsulated electronically addressable contrast media ink discussed in  FIGS. 3-6 ,  FIGS. 7-9  depict other types of electronically active ink systems. In the prior art means are known for depositing metals or resistive materials in a binding medium which may later be cured to form conducting or resistive traces. In the following description novel means are described for depositing semiconductive materials in a binder on a large class of substrate materials in one case and for depositing metals, resistive materials or semiconductive materials outside of vacuum, in an arbitrary pattern, without the need for an etch step and on a large class of substrate materials in another case. 
     In one system a semiconductor ink  350  may be fabricated by dispersing a semiconductor powder  355  in a suitable binder  356 . Said semiconductor powder may be Si, Germanium or GaAs or other suitable semiconductor and may further be with n-type impurities such as phosphorus, antimony or arsenic or p-type impurities such as boron, gallium, indium or aluminum or other suitable n or p type dopants as is known in the art of semiconductor fabrication. Said binder  356  may be a vinyl, plastic heat curable or UV curable material or other suitable binder as is known in the art of conducting inks. Said semiconductive ink  350  may be applied by printing techniques to form switch or logic structures. Said printing techniques may include a fluid delivery system  370  in which one or more inks  372 ,  374  may be printed in a desired pattern on to a substrate. Alternatively said ink system  350  may be printed by means of a screen process  377  in which an ink  380  is forced through a patterned aperture mask  378  onto a substrate  379  to form a desired pattern. Said ink pattern  360  when cured brings into proximity said semiconductive powder particles  355  to create a continuous percolated structure with semiconductive properties  365 . 
     Referring to  FIG. 8  a system is depicted for causing a conductive or semiconductive trace  390  to be formed on substrate  388  in correspondence to an impinging light source  382  which may be steered by means of an optical beam steerer  384 . The operation of said system is based upon a microcapsule  386  which contains a metal or semiconductive salt in solution. Upon being exposed to light  382  which may be a UV light said metal or semiconductive salt is reduced to a metal or semiconductor and said microcapsule is simultaneously burst causing deposition of a conductive or semiconductive trace. 
     Referring to  FIG. 9A , an ink jet system for depositing metallic or semiconductive traces  410  is depicted. In this system a jet containing a metal or semiconductive salt  420  impinges upon substrate  400  in conjunction with a jet containing a reducing agent  430 . As an example, to form a metallic trace silver nitrate (AgNO 3 ) may be used for jet  420  and a suitable aldehyde may be used for the reducing jet  430 . Many other examples of chemistries suitable for the present system are known in the art of electroless plating. In all such examples it is understood that said jets are moveable and controllable such that an arbitrary trace may be printed. 
     Referring to  FIG. 9B  a system which is similar to that of  FIG. 9A  is depicted. In this case an electron beam  470  may be used instead of said reducing jet in order to bring about a reduction of a metal or semiconductive salt emanating from a jet  460 . A ground plane  450  may be employed to ground said electron beam. 
     Referring to  FIG. 9C  an ink jet system for depositing a metallic or semiconductive trace is depicted based on electroplating. In this system a metal or semiconductive salt in a jet  480  held at a potential V may be electroplated onto a substrate  410  thus forming a metallic or semiconductive trace. 
     Referring to  FIG. 9D  means are known in the prior art for UV reduction of a metal salt from an ink jet head. In the present system a jet containing a metal or semiconductive salt  490  may be incident upon a substrate  400  in conjunction with a directed light beam  495  such that said metal or semiconductive salt is reduced into a conductive or semiconductive trace  410 . Alternatively jet  490  may contain a photoconductive material and a metal salt which may be caused to be photoconductively electroplated onto surface  400  by means of application of light source  495  as is known in the field of photoconductive electroplating. 
     Referring to  FIG. 9E  a system is depicted for a moveable deposition head  500  which contains a chamber  520  which may be filled with an inert gas via inlet  510  and which further contains thermal, sputtering, electron beam or other deposition means  530 . Said moveable head  500  may print a metal, semiconductor, insulator, spin material or other material in an arbitrary pattern onto a large class of substrates  540 . In some case such substrate  540  be cooled or chilled to prevent damage from said materials which may be at an elevated temperature. 
     Referring to  FIG. 10  said previously described electronically active ink systems and printing means may be applied to form switch or logic structures, optoelectronic structures or structures useful in radio or magnetic or electric field transmission of signals or power. As indicated in  FIGS. 10A-B  an NPN junction transistor may be fabricated consisting of a n-type emitter  950 , a p-type base  954  and a n-type collector  952 . 
     Alternatively a field effect transistor may be printed such as a metal oxide semiconductor. Such a transistor consists of a p-type material  970 , an n-type material  966  an n-type inversion layer  968  an oxide layer  962  which acts as the gate a source lead  960  and a drain lead  964 . It is readily understood that multiple layers of logic may be printed by using an appropriate insulating layer between said logic layers. Further three dimensional interconnects between different logic layers may be accomplished by means of vias in said insulating layers. 
     Referring to  FIG. 10D  a printed solar cell may be fabricated by printing some or all of a metal contact layer  972 , a p-type layer  974 , an n type layer  976  and an insulating layer  978 . Light  979  which impinges upon said structure generates a current as is known in the art of solar cells. Such printed solar cells may be useful in very thin compact and/or inexpensive structures where power is needed. 
     Referring to  FIGS. 10E-H  elements useful for analog circuitry may be printed. Referring to  FIG. 10E  a capacitor may be printed with dielectric material  983  interposing capacitor plates  981  and  985 . Alternatively the same structure may constitute a resistor by replacing dielectric  983  with a resistive material such as carbon ink. 
     Referring to  FIGS. 10F-H  inductors, chokes or radio antennae may be printed layer by layer. Referring to  FIGS. 10F  and G a first set of diagonal electrodes  989  may be laid down on a substrate. On top of this may be printed an insulator or magnetic core  987 . Finally top electrodes  992  which connect with said bottom electrodes may be printed this forming an inductor, choke or radio antennae. An alternate in-plane structure is shown in  FIG. 10H  in which the flux field  995  is now perpendicular to the structure. 
     The ink systems and printing means discussed in the foregoing descriptions may be useful for the fabrication of a large class of electronically functional structures.  FIGS. 11-14  depict a number of possible such structures which may be fabricated. 
     Referring to  FIG. 11A , an electronic display, similar to one described in a copending patent application Ser. No. 08/504,896, filed Jul. 20, 1995 by Jacobson (now U.S. Pat. No. 6,124,851), is comprised of electronically addressable contrast media  640 , address lines  610  and  620  and logic elements  670  all or some of which may be fabricated with the ink systems and printing means as described in the foregoing descriptions. Said Electronic Display may additionally comprise a data receiver or transceiver block  672  and a power block  674 . Said data receiver block may further be a wireless radio receiver as pictured in  FIG. 11B  in which some or all of the components thereof including antennae  676 , inductor or choke  678 , diode,  680 , capacitor  682 , NPN transistor  684 , resistor  681 , conducting connection  677  or insulation overpass  675  may be printed by the means discussed above. Alternatively said data receiver or transceiver block may be an optoelectronic structure, a magnetic inductive coil an electric inductive coupling or an acoustic transducer such as a piezoresistive film. 
     Said power block  674  may comprise a printed polymer battery as pictured in  FIG. 11C  which consists of in one instance a lithium film  686 , a propylene carbonate LiPF 6  film  688  and LiCoO 2  in matrix  690 . Said power block may alternatively consist of any other battery structure as known in the art of thin structure batteries, a magnetic or electric inductive converter for means of power reception as known in the art, a solar cell which may be a printed solar cell or a semiconductive electrochemical cell which may further have an integral fuel cell for energy storage or a piezoelectric material which generates power when flexed. 
     Such a display  600  as described above further comprising a data receiver or transceiver  672  and power block  674  in which some or all of said components are printed may comprise an inexpensive, lightweight, flexible receiver for visual data and text which we may term “radio paper.” In such a system data might be transmitted to the “radio paper” sheet and there displayed thus forming a completely novel type of newspaper, namely one which is continuously updated. 
     Referring to  FIG. 12  an electrostatic motor which may form an analog clock or watch is depicted which consists of printed conducting elements  720 ,  730 ,  740  and  760  which are printed onto substrate  700 . Said elements, when caused to alternately switch between positive negative or neutral states by means of a logic control circuit  710  may cause an element  750  to be translated thus forming a motor or actuator. In the device of  FIG. 12  some or all of said conducting elements and/or logic control elements may be printed using the ink systems and printing means described in the foregoing description. 
     Referring to  FIG. 13A  a wrist watch  800  is depicted in which the band  820  of said watch contains an electronically addressable display  830  in which some or all of the components of said display, including the electronically addressable contrast media, the address lines and/or the logic are fabricated by means of the ink systems and printing means described in the foregoing description. Such a fabrication may be useful in terms of producing an inexpensive, easily manufacturing and thin display function. Control buttons  810  may serve to control aspects of said display  830 . 
     Referring to  FIG. 13B  it is presently a problem to transmit data or power to a watch band via a wire connection as such connections tend to become spoiled by means of motion of the watchband relative to the watch. In order to overcome this  FIG. 13B  describes a system in which a magnetic or electric inductor  832  in watch band  820  may receive or transmit power or data to a magnetic or electric inductor  834  in watch  800  thus eliminating said wired connection. Said inductor  832  and  834  may be printed structures. 
     Referring to  FIG. 14 , a spin computer is depicted in which dipoles  912  with dipole moment  914  are situated at the nodes of row  920  and column  930  address lines. Such a computer works by means of initially addressing said dipoles to an initial condition by said address lines and then allowing dipole interactions to produce a final state of the system as a whole thus performing a calculation as is known in the art of Spin Ising models and cellular automata. Said dipoles may consist of a dipolar microsphere  912  microencapsulated in a microcapsule  910  or may consist of another form of dipole and/or another means of encapsulation. 
     While this invention has been particularly shown and described with references to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.