Thursday, August 31, 2006

US Patent 7097906 - Single Walled Nanotubes and Diamond-like Carbon

High mechanical strength is one of the favorable properties of single walled carbon nanotubes. However, when formed in bulk, voids between the nanotubes may lead to defects that ultimately may reduce the strength of nanotube materials. This patent proposes a combinaton of nanotubes with another form of carbon with diamondlike structure in order to increase the strength.

Claim 1 reads:

1. A composition of matter, comprising: a pure carbon isotropic alloy having a plurality of allotropic forms of carbon, comprising single-walled carbon nanotubes and diamond-like carbon.

US Patent 7097788 - Conductive Ink Using Oriented Carbon Particles

As mentioned in several earlier postings, printing technology is being explored as part of an alternative manufacturing system for electronics and sensors. This patent teaches a method of increasing conductivity of carbon nanotube based inks printed with inkjet methods. Claim 1 reads:

1. A method of increasing conductivity of an ink, comprising: rubbing the ink to increase conductivity of the ink; followed by conducting electricity through the ink, wherein the ink comprises conductive non-spherical particles comprising carbon, and a solvent, the ink is on a substrate, and the method is carried out without curing at a temperature of at least C. between the rubbing and the conducting.

Tuesday, August 29, 2006

US Patent 7097708 - Donor Atoms For Quantum Computer

Quantum computing promises a new type of logic system for computers based not just on 0 and 1 but rather on a superposition of 0 and 1 allowing for enhanced parallel processing. The nuclear spin of phosphorus nuclei has been proposed as a potential way to enable quantum computing and this patent proposes the use of scanning tunneling microscope (STM) tips as a mechanism for placing the nuclei on a silicon substrate. Claim 1 reads:

1. A method of fabricating a nanoscale or atomic scale product, comprising the following steps: (a) preparing a clean silicon crystal surface; (b) passivating the surface with atomic hydrogen; (c) selectively desorbing single hydrogen atoms from the passivated surface using a STM tip to form a pattern of exposed areas in the hydrogen layer, where the areas are spaced from each other by 100 nm or less; (d) exposing the patterned surface to donor molecules to produce an array of single donor atom bearing molecules in the exposed areas; (e) annealing the arrayed surface at between about C. to about C. to incorporate electrically active donor atoms into the silicon.

US Patent 7096741 - MEMS Shock Reduction

This patent (priority July 14, 2004) proposes reduction of shock sensitivity in micromechanical devices as a patentable concept. Representative claims include claims 1 and 9:

1. A method for reducing operational shock sensitivity of a MEMS device comprising: detecting a shock experienced by the MEMS device; and, altering closed-loop parameters of the MEMS device in dependence upon the detected shock such that effects of the shock are other than compensated for.

9. A method for reducing operational shock sensitivity of a MEMS device comprising: controlling the MEMS device using a closed-loop control circuit, the closed-loop control circuit including a movable MEMS structure, a detector for sensing a position of the MEMS structure and for providing a feedback signal related to the sensed position, and a processor for receiving the feedback signal and for providing a control signal used to control the MEMS device, the control signal determined in dependence upon the feedback signal; detecting a shock experienced by the MEMS device; and, altering the control signal in dependence upon the detected shock such that a response of the closed-loop control circuit to the shock is minimized.

Claim 1 refers to the alteration of the control parameters of the micromechanical structure to avoid prolonging the effects of shock. Ignoring the fact that this claim is poorly phrased in a contradictory fashion the purpose seems to avoid an overcompensation that would actually prolong the effects of shock (see column 5, lines 19-32 of '741).

Claim 9 (and several of the other independent claims) seems clearly directed to minimizing feedback response when shock is detected.

Unfortunately the patent examiner may have missed the following prior art patents which seem relevant:

US 6327909 (filed Nov. 30, 1999)

A bistable sensor with a tunable threshold for use in microelectromechanical systems. The sensor uses electrostatic force to modify the threshold and to disable the sensor in a deflected position once a sustained extreme in vibration is detected. Potential applications include mechanical implementations of signature analysis to automatically eliminate large amplitude noise at a specific frequency, shock detection without requiring quiescent DC power consumption, and determination of the magnitude of a shock.

US 6374677 (filed Feb 22, 2000)

A micromechanical resonator including a motion arresting mechanism to rapidly damp the vibration of a resonator beginning at any given moment in time to remove vibration caused by previous events. An electrostatic clamp uses a bias voltage between an electrode and the resonator to damp the resonator and return it to its equilibrium position. A mechanical clamp includes an actuator that forces the mechanical clamp to contact the resonator. These micromechanical resonators facilitate condition based monitoring of complex electromechanical machines and components by allowing signature analysis in multiple temporal and frequency domains.

Monday, August 28, 2006

US Patent 7095822 - X-Ray Near Field Microscope

In the early 1980's a new series of microscopes were invented by IBM and others which were capable of resolving images on the atomic level. As opposed to more conventional microscopes using light or electrons these microscopes were characterized by sharp probe tips which were held in proximity to the sample being inspected. Due to their high resolving power and sensitivity these new microscopes set the stage for many of the developments in nanotechnology happening today. This patent modifies one of the basic types of these new microscopes to control x-ray beams used to probe a sample. Claim 1 reads:

1. An x-ray probe system, comprising: a target supported adjacent a sample surface which is integrated into a probe tip of an atomic force microprobe (AFM); and a beam source for generating an energetic beam to generate x-ray emissions from the target to probe the sample.

Sunday, August 27, 2006

US Patent 7095645 - Nanobeam Memory

The use of nanotubes to form mechanical memory devices has been developed primarily using ribbons of nanotube by a company named Nantero. This patent from Ambient Systems takes a slightly different approach. It uses individual nanotubes in a cantilever configuration to form a nanobeam. A series of control electrodes surround the nanotube and are maintained at balancing potentials that keeps the nanotube at a central equilibrium position. Removing or altering potential from one of the electrodes eliminates the equilibrium state and creates a specific memory state in which the nanotube moves to one of a plurality of sensing positions. With this configurations two, three, or more memory states (depending on the number of balancing electrodes) can be stored per nanotube. Claim 1 reads:

1. A nanometer-scale memory cell comprising: a base; a mounting assembly attached to said base; a nanometer-scale beam fixed to said mounting assembly and having a first portion that is free-to-move; and a first charge containment layer isolated by non-conductive layers and coupled to said base in the proximity of said first free-moving portion, being able to store a first charge profile in said charge containment layer without moving said nanometer-scale beam.

Thursday, August 24, 2006

US Patent 7094617 - Optoelectronic Nanodot Manufacture

This patent involves the manufacture of nanodots for light sensors or radiation devices. It teaches the formation of a dual layer hole-injection/electron-injection structure for the nanodot. Claim 1 reads:

1. A method of manufacturing an optoelectric device, comprising the steps of: forming an electron injection layer on a semiconductor substrate; growing nano dot layer on said electron injection layer by an epigrowth method; heating said nano dot layer so that said nano dot has a dual structure comprising an external nano dot and an internal nano dot; and forming a hole injection layer on the overall structure.

The interesting thing about this patent is that it has the cleanest prosecution history I've ever seen. The application was allowed by the Examiner on a first action (most patent applications initially have at least one claim rejected). The Examiners reasons for allowance read:

"The following is the examiner's statement of reasons for allowance: See claim 1 and the prior art search history for claim 1."

Unfortunately there is very little indication of non-patent literature searching except for IBM_TPB which is a very limited source. What is worse is that the Examiner limited the search for terms including nano adjacent to dot excluding patent references using nanodot (one word) or quantum dot or nanocrystal or nanoparticle, etc. to describe the invention.

Wednesday, August 23, 2006

US Patent 7094441 - Low Temperature Interconnection of Nanoparticles

Gratzel cells are special solar cells which use organic dye and nanoscale titanium dioxide to obtain electrical current from light. One limitation of these solar cells is that high temperatures are necessary (>400 C) to provide interconnection between the nanoparticles during fabrication. These high temperatures limit the substrate material on which the cells are formed to rigid materials such as glass. However, the ability to form solar cells on flexible materials would allow the cells to be more easily incorporated in a wider variety of applications. This patent uses a polymeric linking agent to form the cells which in some examples may provide interconnections at room temperature.

1. A method of interconnecting nanoparticles at low temperature, the method comprising the steps of: providing a solution comprising a polymeric linking agent having a backbone structure which includes the formula -[A-O--].sub.m- and a solvent; wherein A is a metal and m is an integer greater than zero; and contacting a plurality of metal oxide nanoparticles with the solution at a temperature below about C. to interconnect at least a portion of the plurality of metal oxide nanoparticles.

Tuesday, August 22, 2006

US Patent 7094361 - Low Attenuation Optically Transparent Nanocomposites

Attenuation is a critical parameter for optical fiber construction. For long distance transmission greater attenuation requires a larger number of repeaters which greatly increases the expense of the transmission system. High purity silica glass is used in most modern fiber optics to achieve attenuation as low as 0.2 dB/km but research is ongoing to find alternative materials without the brittleness or difficulty in fabrication of high purity silica fibers. This patent is based on the discovery that for dispersed particles of a size of 10-1000 nm in a polymer matrix light is scattered in proportion to the sixth power of the particle diameter. This means that a reduction in particle diameter of ten will lead to reduction in scattering by a factor of a million. Claim 1 reads:

1. An optically transparent composite material comprising solid solution inorganic nanoparticles dispersed in a host matrix inert thereto, wherein said nanoparticles are doped with one or more active ions at a level up to about 60 mole% and consist of particles having a dispersed particle size between about 1 and about 100 nm and said composite material with said nanoparticles dispersed therein has an attenuation of less than 10 dB/cm and is optically transparent to wavelengths at which excitation, fluorescence, or luminescence of said active ions occur.

Monday, August 21, 2006

US Patent 7092287 - SiN Nanodot Memory

The use of nanodots as charge storage elements is a proposed technique to overcome the problems of charge retention in nanoscale floating gate memory devices. Si has been used to form such nanodots but is subject to oxidation. This patent proposes using SiN nanodots and fabricating the nanodots by exposing silicon nanodots to nitrogen containing gas. Claims 1,17,23, and 28 are representative.

1. A method for the formation of silicon nitride nanodots on a semiconductor substrate, the method comprising the steps of: forming silicon nanodots on the semiconductor substrate; and nitriding the silicon nanodots by exposing the silicon nanodots to a nitrogen containing gas.

17. A method for forming a memory device, comprising: depositing a discontinuous silicon layer on a substrate; and nitriding the discontinuous silicon layer.

23. A non-volatile memory device comprising: a semiconductor substrate; a plurality of silicon nitride nanodots across an area of the substrate, the silicon nitride nanodots having an average size between about 1 nm and 100 nm and covering between about 10% and 50% of the area of the substrate.

28. An integrated circuit, comprising a substrate having a plurality of silicon nitride nanodots, wherein a core region of at least some of the nanodots has a lower nitrogen concentration than a surface region of the at least some of the nanodots.

Sunday, August 20, 2006

US Patent 7091924 - MEMS Reconfigurable Antenna

High frequency communication devices are benefiting from microelectromechanical systems that allow for electrically steerable microantenna elements that can be mechanically reconfigured to provide variable impedance parameters. This patent employs a series of micromechanical hinges to rotate respective antenna arms and form a reconfigurable vee antenna. Claim 1 reads:

1. A MEMS reconfigurable vee antenna comprising: a transmission line end comprising conductors; antenna arms, each of the antenna arms being rotatably coupled to a corresponding one of the conductors; actuator mechanisms; support arms, each of the support arms having one end rotatably coupled to a corresponding one of the antenna arms and the other end rotatably coupled to a corresponding one of the actuator mechanisms; first micro-mechanical hinges, each of the first micro-mechanical hinges rotatably coupling one of the antenna arms to a corresponding one of the conductors; second micro-mechanical hinges, each of the second micro-mechanical hinges rotatably coupling one end of a corresponding one of the support arms to a corresponding one of the antenna arms; and third micro-mechanical hinges, each of the third micro-mechanical hinges rotatably coupling one end of a corresponding one of the support arms to a corresponding one of the actuator mechanisms; wherein, for each of the actuator mechanisms, when the actuator mechanism is controlled to move linearly forward, the corresponding support arm pushes on the corresponding antenna arm so as rotate the corresponding antenna arm inward, and when the actuator mechanism is controlled to move linearly backward, the corresponding support arm pulls on the corresponding antenna arm so as rotate the corresponding antenna arm outward.

Thursday, August 17, 2006

US Patent 7091120 - Blade Coating of Aligned Nanowires

The semconductive properties of nanowire composites are determined by various parameters including nanowire type, doping concentration, nanowire density, and nanowire orientation. Oriented nanowires are more desirable than random orientations to achieve anisotropic effects and improved conduction in the direction of alignment. Previous techniques to achieve such alignment include fluid flow alignment, ion flow alignment, and e-field alignment strategies. This patent claims the use of extruding or blade alignment to achieve such alignment. Claim 1 reads:

1. A process for producing a nanowire-material composite, comprising: (a) contacting nanowires with a material to form a mixture; and (b) blade coating or extruding said mixture on a substrate to form a nanowire-material composite such that said nanowires are aligned parallel to their long axis on said substrate.

Wednesday, August 16, 2006

US Patent 7091096 - Electrochemical Fabrication of Nanotube FET


One of the most significant problems in nanotube-based electronics is the separation of metallic-type nanotubes from semiconductive-type nanotubes. In order to form a nanotube transistor semiconductor-type nanotubes are necessary, however most of the fabrication procedures used to make nanotubes produce a mixture of both types. Several techniques have been developed to sort the semiconductive-type from the metallic-type and other techniques use current burn off methods to remove the unwanted metallic-type. This patent proposes an electrochemical approach that electrically neutralizes the metallic type nanotubes so as to create nanotube field effect transistors. Claim 1 reads:

1. A method of fabricating a structure with field-effect transistors, said transistors each comprising a source electrode, a drain electrode, a channel extending between the source and drain electrodes and at least one gate electrode associated with the channel for controlling the conductance of the channel, wherein the channel comprises one or more semiconducting single-wall carbon nanotubes, the method including the steps of a) depositing a plurality of single-wall carbon nanotubes on a substrate, said carbon nanotubes comprising a mixture of metallic carbon nanotubes and semiconducting carbon nanotubes, b) providing before or after step a) source and drain electrodes on the substrate so that one or more carbon nanotubes extend between the source and drain electrodes, c) applying a variable gate voltage to switch off the semiconducting tubes extending between the source and drain electrodes, d) wetting the surface of the structure including the transistors with a chemical to achieve a chemical bond between a radical supplied by said chemical and some carbon atoms of the metallic nanotubes, whereby these metallic nanotubes become non-conductive.

Tuesday, August 15, 2006

US Patent 7090891 - Fabrication of Fuel Cells Using Nanostructured Material

Solid oxide fuel cells (SOFCs) are currently proposed as an alternative for power plants. Traditional SOFCs require high operating temperatures (~1000 C) which limits the number of possible materials usable to make the SOFCs. This patent proposes using nanostructured cerium dioxide and copper oxide in the fabrication of SOFCs to reduce the operating temperature and ultimately reduce the cost of manufacturing and operating SOFCs. Claim 1 reads:

1. A method of fabricating a solid oxide fuel cell comprising: dispersing ceria and doped ceria nanoparticles in a first colloidal solution; atomizing the first colloidal solution into a spray; depositing the spray onto a substrate to form a thin film interfacial layer having a thickness in the range of 100 nm to 10 microns; and forming an anode from a nanocomposite of ceria and CuO at low temperature over the interfacial layer.

Monday, August 14, 2006

US Patent 7087946 - Nanowire Gap Circuits

HP is very active in the development of molecular crossbar arrays which are useful in creating ultradense molecular memory devices and reconfigurable electronic devices. Usually these crossbar arrays employ crossing rows of nanowires and columns of nanowires fromed in different layers with molecular material formed between the different layers. This patent exploits self-assembling manufacturing techniques to form the row and column nanowires in a common layer with a gap formed between them for placement of the molecular material. Claim 1 reads:

1. An electric device comprising: a first elongated nanowire on and touching an insulating surface and a second elongated nanowire on and touching the same side of said insulating surface, said first nanowire having a first straight portion and said second nanowire having a second straight portion, said first straight portion and said second straight portion forming a T-shaped structure, said first and second straight portions separated by a gap of between 0.4 nm and 10 nm.

US Patent 7087921 - Nanotube RF Switch

Nanotube based FETs have been demonstrated by several different universities and corporations. Usually these designs employ the traditional source/drain/gate configuration of FET transistors, however this patent proposes a modification of this design. Instead of using a direct contact between the gate contact and the nanotube, the gate of this patent is used as an EM wave source to alter the conductive properties of a nanotube fixed between the source and drain conductors. Claim 1 reads:

1. A driving method of an electronic apparatus having an active electronic device including a carbon nanotube, a first electrode connected to one end of the carbon nanotube, a second electrode connected to the other end of the carbon nanotube, and a third electrode placed near the carbon nanotube to irradiate the carbon nanotube with electromagnetic waves, the method comprising: causing the third electrode to output electromagnetic waves; and varying a frequency of the electromagnetic waves to control a conductance of the carbon nanotube, wherein the frequency includes at least a predetermined frequency so that the conductance of the carbon nanotube is increased.

US Patent 7087920 - Conductively Switchable Nanowire

An emerging area which may be less familar then nanotechnology, but which may have more near term economic impact, is morphware, otherwise referred to as reconfigurable electronics. Traditionally electronics has been divided into hardware, which refers to the physical electrical components such as specific logical or analog circuits, and software, which refers to the instructions in the form of binary patterns to be carried out by the hardware. However, the emergence of materials whose conductivity/resistance can be programmed allows for not just the software to be altered but for the actual electronic hardware to be adjusted and adaptable to different conditions. As an example, using "morphware" technology a circuit originally configured as an FM radio receiver can change into a circuit for a cell phone at a push of a button. Also there is the potential for circuit optimization under different conditions (temperature, frequency of use, etc.) and to learn user preferences in the same way a device such as TIVO learns to anticipates a user's prefered television programs. Currently the Dept. of Defense (specifically DARPA) is investing in the development of this technology, but private enterprise such as Hewlett Packard is also making some practical headway.

This patent from HP uses a doped nanowire with conductivity selectively programmable in accordance with temperature to configure a circuit. Claim 1 reads:

1. A nanowire comprising: a single crystalline semiconductor material having an exterior surface and an interior region; and one or more dopant atoms, wherein at least a portion of the nanowire thermally switches between two conductance states, the two conductance states being a high conductance state and a low conductance state, and wherein in the high conductance state, a first fraction of the dopant atoms are in the interior region and a second fraction of the dopant atoms are at the exterior surface, and wherein in the low conductance state, a third fraction of the dopant atoms are in the interior region and a fourth fraction of the dopant atoms are at the exterior surface, the first fraction being greater than the third fraction and the second fraction being less than the fourth fraction.

Thursday, August 10, 2006

US Patent 7087523 - Nanofabrication Using Melting and Resolidification of Nanoparticles

Printing techniques are more and more often being applied to achieve nanoscale fabrication as an alternative to the traditional silicon processing methodologies, which are expensive and require specialized environments (clean room, low pressure, high temperature, etc.) This patent employs an inkjet type mechanism to print nanoparticle containing fluid in a desired pattern. The nanoparticles are melted by a laser and then solidified to form desired nanostrutures.
Claim 1 reads:

1. A method fo producing a structure on a substrate comprising the steps of a) depositing drops of a suspension onto a substrate, wherein in said suspension comprise nanoparticles of a material suspended in a liquid; and, wherein said a substrate lacks recesses in the region where said drops are deposited onto said substrate; and, b) exposing said nanoparticles an said substrate to at least one localized spot of laser light such that said nanoparticles are at least partially melted by said at least one localized spot of laser light; and, c) solidifying said at least partially melted nanoparticles, forming thereby said structure on said substrate.

Wednesday, August 09, 2006

US Patent 7087207 - E-Field Assisted Nanotube Array Formation

Ordered arrays of single walled nanotubes (SWNTs) have certain advantages over disordered arrays (such as improved conductivity or anisotropic properties). However, many of the techniques used to fabricate SWNTs result in disordered arrays of nanotube material. This patent from Rice University proposes using electric fields to facilitate the extension of SWNTs from a nanotube composite and forming an ordred array. Claim 1 reads:

1. A method for forming an array of single-wall carbon nanotubes comprising: (a) providing a material comprising single-wall carbon nanotubes, wherein the material has a surface; (b) subjecting the surface to oxidizing conditions sufficient to cause the single-wall carbon nanotubes to break and protrude from the surface; and (c) applying an electric field to the surface to form an array comprising the single-wall carbon nanotubes on the surface.

Tuesday, August 08, 2006

US Patent 7086451 - Nanotubes Grown On Heat Sink

Along with excellent mechanical and electrical characteristics, carbon nanotubes are known for excellent thermal conductivity. However, using randomly oriented nanotubes is not optimum for thermal conductivity. This patent instead proposes the growth of parallel nanotubes oriented perpendicular to the base of a heat sink to make the conduction from a heat source attached to the base uniform. Claim 1 recites:

1. A heat sink comprising: a base; a plurality of fins extending from one surface of the base; and a plurality of carbon nanotubes grown on and thereby in contact with an opposite surface of the base; wherein the carbon nanotubes are substantially parallel to each other and substantially perpendicular to the base.

Wednesday, August 02, 2006

US Patent 7085125 - Nanotube Energy Collector

The electron emission properties of nanotubes have been exploited to create a variety of devices include flat panel displays, electron microscopes, and microwave amplifiers. Usually the electron emission from the nanotubes is generated by the application of an electric field. This patent, however, instead exploits the ability of nanotubes to emit electrons based on thermal (heat), photonic (light), or phononic (vibrational) interaction with the nanotubes. This allows for the creation of solar panels or heat engines that can generate electric current. Given that nanotube composites can be formed on flexible supports this could allow for embedded solar panels or other energy converting devices into clothing, plastics, etc. Claim 1 reads:

1. A carbon nanotube electrical device comprising: a) a cathode having a carbon nanotube coating, said carbon nanotube coating comprising either substantially aligned carbon nanotubes grown on the cathode or randomly oriented carbon nanotubes in a binder; b) an anode placed in an electrically conductive relationship with the cathode, such that there is a space between the cathode and the anode; and c) an energy collector coupled to the cathode opposite the carbon nanotubes, the energy collector configured for collecting thermal, photonic, or phononic energy.

Tuesday, August 01, 2006

US Patent 7083104 - RFID with Nanowire Transistors

The term "microelectronics" is now often referred to as "nanoelectronics" due to the reduction of critical feature sizes below 1 micron. However, Nanosys is a company that is instead focusing on "macroelectronics". While Nanosys exploits nanostructured materials, they are more concerned with manufacturing large area (i.e. macro) electronic structures out of a variety of substrates that can provide more flexibility and less fragility than silicon electronics. These "macroelectronic" devices may be embedded into clothing, food packaging, and a variety of other structures and provide features such as disposable electronic displays or large array sensors. This patent focuses on "macroelectronic" RFID tags that can be made using nanowires. Claim 1 reads:

1. A radio frequency identification (RFID) tag, comprising: an antenna; a beam-steering array that includes a plurality of tunable elements, each tunable element including: a plurality of phase-adjustment components; a switch corresponding to each phase-adjustment component, said switch including a transistor formed by a thin film of nanowires in electrical contact with source and drain contacts; wherein said switch enables said corresponding phase-adjustment component to change a phase of said tunable element; wherein an electromagnetic (EM) signal transmitted by said antenna is redirected by said beam-steering array.