Thursday, June 29, 2006

US Patent 7067098 - Single Walled Nanotube Array

As noted in earlier postings, many of Richard Smalley's (Nobel Prize winner for discovering fullerenes) fundamental patents on single walled nanotubes and their fabrication are only now being issued, even though they have filing dates going back to 1996. Whether this is a deliberate strategy of the patent attorney's or not it may present some potential interference problems. This patent presents a broad claim to two dimensional nanotube arrays. Claim 1 reads:

1. A substantially two-dimensional array comprising single-wall carbon nanotubes, wherein (a) the single-wall carbon nanotubes have ends, (b) said ends are ordered in substantially the same plane, and (c) said ends form the substantially two-dimensional array.

As noted in earlier postings, arrays of vertical nanotubes have found extensive uses as electron emission sources and much investment has already been initiated in developing flat panel displays using such technology. Till Keesmann, the owner of the fundamental patent on electron emitting nanotubes ( also disclosed use of single walled nanotube arrays (see figure 5 and column 3,lines 32-47) although they were referred to as "single-shell carbon nano-cylinders". Keesmann's priority goes back to Aug.23, 1996 in the US but has foreign filing priority to Feb. 22 1995. Smalley's priority goes to Aug. 8, 1996 so Smalley has the US priority but not the foreign priority. I've actually heard about cases like this when I was a Patent Examiner and there is no clear resolution other than an interference hearing.

The one silver lining is that most nanotube array applications can use double walled or multiwall nanotubes instead of single walled nanotubes and thus Smalley's claim may not be that powerful except for applications where single walled nanotubes are absolutely necessary.

US Patent 7067096 - Carbon Nanotubes with Carbon Nanohorns

One of the problems of carbon nanotube fabrication is that the nanotubes are sticky and tend to bundle together during manufacture. This presents difficulties for applications requiring extracting individual nanotubes. This patent proposes a solution of combining carbon nanotubes with carbon nanohorns, which are similar to nanotubes except having a horn shape instead of a cylinder shape. The nanohorns act as a wedge between the nanotubes to facilitate nanotube separation. Claim 1 reads:

1. A carbon nanotube-carbon nanohorn complex, which comprises a dispersion comprising carbon nanotubes and carbon nanohorns, said dispersion being aggregated to form a complex.

US Patent 7066998 -Surface Enhanced by Nanoparticles

Coating films may provide several useful properties in a variety of applications including drying, anti-soiling, glossiness, color, and smoothness control. Typically paints and varnishes have been used for such films but the inventors of this patent have found nanoparticle films with a low water content provide improved properties. Claims 1 and 13 read:

1. A surface coating film for at least partially covering a surface, said coating film comprised of a plurality of nonphotoactive nanoparticles which are present in an amount less than 3 microgram/square cm of the area of the surface.

13. A surface coating film for at least partially covering a surface, said coating film comprised of a plurality of nonphotoactive nanoparticles and water, said film having a water content of less than or equal to about 4%.

Tuesday, June 27, 2006

US Patent 7066513 - Nanotweezers With Voltage Release

Many people are familiar with nanotechnology from the popularization of replicating "nanorobots" advanced by futurists such as Eric Drexler and other science-fiction writers. However, most of the ideas associated with Drexler do not really match up with reality. One of the main problems is that "nanorobots" and a mechanical replication system, as imagined by Drexler, for reproducing "nanorobots" is limited by the sticking factor of chemicals. While a device is conceivable for mechanically "picking up" individual molecules (this has in fact been done with scanning probe microscopes) it is considerably more difficult to "let go" of the molecule when it is placed in a desired position. Nanotweezers are one device developed by Daiken Chemical of Japan that actually attempts the mechanical synthesis approach. In order to solve the stickiness problem they use electrostatic repulsion to release molecules. Claim 1 reads:

1. An operation method of nanotweezers that are comprised of two or more nanotubes which are fastened at base end portions thereof to a holder and hold and release a nanoscale material by way of opening and closing tip end portions thereof, said method comprising the steps of: confirming a position of said nanoscale material by way of imaging a surface of a specimen by a scanning type probe microscope; moving said nanotweezers to a position over said nanoscale material; descending said nanotweezers which are in an opened state and then closing said nanotweezers so as to hold said nanoscale material; raising said nanotweezers that hold said nanoscale material and then moving said nanotweezers to an objective position; and descending said nanotweezers that hold said nanoscale material and then opening said nanotweezers so as to release said nanoscale material on said objective position which is on said surface of said specimen; wherein a voltage is applied between said nanotweezers and said specimen when said nanotweezers are opened so as to release said nanoscale material.

US Patent 7066234 - Anodic Aluminum Oxide Nanoimprinting Stamp

Nanoimprint lithography is a very promising approach to facilitate less expensive nanopatterning and is more suitable to mass fabrication than some other serial nanofabrication approaches such as scanning probe lithography or e-beam lithography. Basically nanoimprint lithography employs a stamp structure with nanoscopic grooves formed therein which is used to transfer a pattern. However, formation of the nanostamp itself is often a difficult process. This patent employs the use of anodic aluminum oxide (AAO) which have nanoporous structure to form the stamp. Interestingly, in other nanotechnology applications AAO films are also used as templates for growing vertical arrays of carbon nanotubes. Claim 1 reads:

1. Method for producing a stamping tool with a structured stamping surface, comprising the steps of: oxidizing a surface or covering layer of the stamping tool for forming the stamping surface at least partially anodally and forming open hollow chambers that are at least essentially uniformly shaped and at least essentially evenly distributed over the surface or surface area of the stamping surface without the use of a model.

Monday, June 26, 2006

US Patent 7065285 -Quantum Dots in Aromatic Polymer Matrix

A variety of glass and polymer materials have been used to construct optical fibers, optical amplifiers, optical switches, and various other optical devices. Typically polymer materials are less favored because, even though polymers are generally tougher more durable than glass materials, polymers produce greater signal attenuation. This patent proposes the use of quantum dots in an aromatic (C6H6 based) polymer to facilitate the production of improved optical waveguides and other optical devices. Claim 8 is representative:

8. A composition of matter, comprising: a polymer matrix including polymer chains having a plurality of carbon-fluorine bonds; and a plurality of quantum dots distributed within the polymer matrix, wherein the polymer chains include aromatic groups.

Sunday, June 25, 2006

US Patent 7064474 - Tapered Nanotube Array

As noted in the previous posting, vertical nanotube arrays have been around for several years now with the major current application being flat panel displays and with future applications such as parallel electron beam lithography (for high volume nanoscale fabrication) looking promising. However, one hurdle for this technology is the field screening effect which basically limits the current density produced from closely spaced electron emitting nanotubes. This patent proposes an interesting configuration to reduce the field screening effect by tapering the lengths of groups of nanotubes at spaced intervals greater than 1 micron. Claim 1 reads:

1. A carbon nanotube array comprising: a plurality of carbon nanotubes, the carbon nanotubes being parallel to each other and cooperatively forming a plurality of lower portions and a plurality of corresponding tapered tips above the lower portions; wherein distances between adjacent tips are approximately uniform, and the distance is more than one micrometer.

US Patent 7064372 - Large Area Nanowire Array

Occasionally when applicants start claiming ranges of size or quantity in their patents, Examiners start to make stupid decisions. The reason for this is that some ranges, while common to those or ordinary skill in the pertinent art, are not discussed in the prior art patent literature that many Examiners rely upon. This particular patent claims:

1. An article, comprising a population of nanowires disposed in a thin film on a surface of a substrate, wherein: the population of nanowires is substantially oriented in a first direction; and the thin film has an area of greater than 10 cm^2.

However, vertically aligned nanotubes have been proposed for flat panel displays since the late 1990's, predating this patent's earliest filing date. See for example, US 6,283,812, column 12, lines 6-51. Given that flat panel displays were conventionally formed larger than 10 cm^2 before this patents earliest filing date it would seen that this patent was allowed in clear error and should be invalidated or reexamined.

Saturday, June 24, 2006

US Patent 7064341 - Coated Nanotube For Scanning Probe Microscope

While this blog covers both nanotechnology and micromechanical (MEMS) related patents, nanotechnlogy and MEMS are very different disciplines involving different manufacturing techniques, different materials, and different applications. However, scanning probe microscopes unite the world of MEMS and the world of nanotechnology by providing a MEMS device with a sharp tip capable of manipulation or detection on the nanoscale. This nanoscale detection is made easier by forming the sharp tip out of nanotubes which provide high aspect ratio tips for detection or manipulation in regions that conventional scanning probe tips can not access. This patent deals with reducing the vibration when using nanotubes as the scanning probe tip by providing a coating over the nanotube tip (which may also be used to facilitate bonding between the nanotube and scanning probe). Claim 1 reads:

1. A coated nanotube surface signal probe characterized in that said probe comprises a nanotube (24), a holder (2a) which holds said nanotube (24), and a coating film (29) fastening a base end portion (24b) of said nanotube (24) to a surface of said holder with a tip end portion (24a) of said nanotube (24) being caused to protrude from said holder (2a) wherein said probe is assembled by direct observation in an electron microscope, said coating film is formed by irradiating a base end portion of said nanotube (24) with an electron beam in said electron microscope so as to fasten said nanotube (24) to said holder (2a) by said resulting coating film (29), and said tip end portion (24a) is used as a probe needle so as to scan surface signals.

Thursday, June 22, 2006

US Patent 7064000 - Chemical Assembly of Molecular Circuit With Defect Mapping

Molecular crossbar array electronics is one of three leading platforms for nanoelectronic circuits that are likely to have a major impact in the next ten years (the other two being nanotube electronics and quantum electronics). Hewlett-Packard is the major player backing this technology and, while initial applications are in high density memory, there are already several patents on latches, logic circuits, multiplexers, and other devices formed using this technology. A primary advantage of this technology is not just that it is adaptable to nanoscale dimensions but that the circuits formed with this technology may be dynamically reconfigured. While conventional electronic processors may be reprogrammed via software, molecular crossbar arrays have the potential for the actual hardware to be altered so that one type of circuit can change or adapt to become another type of circuit (for example changing a signal filter into a pulse generator, changing an AND gate to an OR gate, etc.)

This patent comes from Carnegie Mellon University (funded by DARPA) and provides for defect mapping during the fabrication of molecular crossbar arrays. Claim 1 reads:

1. A method for constructing a molecular nanoblock using chemically assembled electronic nanotechnology, comprising: forming an array of electrical wires on a substrate via a chemical self-assembly process; aligning the array of electrical wires; combining the array of electrical wires and forming a two dimensional grid-like structure; creating an active electronic device at an intersection point of two wires on the grid-like structure; and generating a defect map of the grid-like structure.

Wednesday, June 21, 2006

US Patent 7063753 - Magnetic Alignment of Nanotubes

In order to take advantage of the conductive or semiconductive properties of nanotubes it is often necessary to align a plurality of nanotubes since the conductive/semiconductive property is anisotropic (i.e. directionality dependent). This patent provides a mechanism to provide such alignment using magnetic atoms attached to nanotubes to regulate the alignment of nanotubes in a magnetic field. Claim 1 reads:

1. A method comprising: creating a plurality of nanotubes, the nanotubes each having a substantially cylindrical wall and a plurality of magnetic atoms that are attached to the wall; aligning the nanotubes on a grid having metal lines, such that each of the nanotubes has a first portion that overlaps a metal grid line and a second portion that does not overlap the metal grid line; and removing the second portions.

Tuesday, June 20, 2006

US Patent 7062848- Nanostructured Ink For Printing Electronics

Modern fabrication facilities for semiconductor electronics represent a multi-billion dollar investment requiring numerous peripheral mechanisms for maintaining high vacuums and requiring process steps using high temperatures and expensive masking elements. Also, modern electronic fabrication facilities, while good at working with semiconductor substrates such as silicon, are unworkable for forming electronics on alternative substrates such as plastic, coated paper, or biocompatible films which may prove beneficial for a variety of emerging applications. It would be useful to find a cheaper process for producing electronic structure not constrained by the limitations of the silicon-based semiconductor industry.

A leading candidate for 21st century manufacturing may turn out to evolve from the printing industry. Using conductive and semiconductive nanoparticles contained in a liquid composition electronic devices can be literally printed onto a wide variety of substrates allowing for cheaper devices with new functionalities. Hewlett-Packard, one of the industry leaders in printing technologies as well as the industry leader in molecular electronics, is leveraging it's cumulative knowledge to establish a new standard for electronic manufacturing based on printing. This patent is indicative of HP's development in electronic device printing. Claims 1,25,and 37 are representative.

1. A printable composition, comprising: a) a liquid carrier; b) a plurality of nanostructures having an aspect ratio of at least about 5:1 within the liquid carrier; and c) a stabilizing agent configured to inhibit agglomeration of the plurality of nanostructures, said stabilizing agent being a nanostructure surface attached ligand, nanostructure polymeric coating, metal coating, semimetal oxide coating, or metal oxide coating.

25. A method of forming a conductive path on a substrate, comprising: a) applying a printable composition onto a substrate, said printable composition including: i) a liquid carrier; and ii) a plurality of nano structures having an aspect ratio of at least about 5:1 within the liquid carrier; and b) removing at least a portion of the liquid carrier, wherein the plurality of nano structures are in sufficient contact to provide the conductive path, said conductive path being a trace, transistor, resistor, inductor, gate, diode, capacitor, magnet, or combination thereof.

37. A system for forming conductive paths on a substrate, comprising a printhead having a firing chamber reservoir containing an ink-jettable composition, said ink-jettable composition including a liquid vehicle; a plurality of nanostructures having an aspect ratio of at least about 5:1 within the liquid vehicle; and a stabilizing agent configured to inhibit agglomeration of the plurality of nanostructures, said stabilizing agent being a nanostructure surface attached ligand, nanostructure polymeric coating, metal coating, semimetal oxide coating, or metal oxide coating.

It is interesting to note that, in addition to printing electronic devices, HP also has a patent for printing batteries.

Monday, June 19, 2006

US Patent 7061660 - MEMS Feedback Control

Most people familiar with the patent system realize that the US patent office typically issues several bad patents every week. This may be understandable given that several thousand patents are issued in any give week and, based upon even a conservative error rate estimate of a few percent, dozens of bad patents can result. Many of these bad patents result from prior art that is well known but not readily searchable in patent or technical databases or prior art that is hidden within a singular embodiment of a single reference. However, a few of these bad patents issue when there is a large quantity of available prior art but the Examiner somehow misses all of the art. This patent represents an extreme case of the latter. Claims 1 and 8 are exemplary:

1. A MEMS device, comprising: at least one movable member; semiconductor device having at least one property affected by the location of the movable member with respect to the semiconductor device; and a control circuit to limit movement of the movable member based on observation of the property affected by the semiconductor device.

Claim 1 basically covers many micromechanical accelerometers formed from silicon using feedback regulation for which hundreds of patents and pieces of technical literature have been published. One applicable example is

8. A MEMS device of comprising: at least one movable member; a tunneling device having at least one property affected by the location of the movable member with respect to the tunneling device; and a control circuit to limit movement of the movable member based on observation of the property affected by the tunneling device.

Claim 8 basically covers most scanning tunneling microscopes for which hundreds of patents and pieces of scientific literature have been published over the last twenty years. One applicable example is

One may ask how could a Patent Examiner allow a patent application with so much prior art against the claims? The answer lies not just in this individual Examiner's negligence but in the failure of the US patent office to form a centralized resource for searching MEMS related patents (or perhaps create a MEMS art unit?). Since this particular patent had some dependent claims drawn toward optical devices, the application went to an Examiner in the optical arts, who may know a lot about optics, but very little about the broader application of MEMS.

Lacking a centralized resource to search MEMS patents it is likely that many more of these bad patents will issue in the MEMS arena.

Sunday, June 18, 2006

US Patent 7061008 - Quantum Computer Including Phosphorus Bearing Molecules on Hydrogenated Silicon Substrate

Quantum computing involves the use of coherence between electrons or other elementary particles to perform numerous computation in parallel (i.e. simultaneously). At a theoretical level such quantum computers have been proposed to enable fast factorization of large numbers, which may undermine current standards of cryptography and cryptanalysis used in internet security and in communication systems used by some US and foreign intelligence agencies. So far a lack of maintaining persistence of coherence among a large number of electrons has limited the potential of quantum computing, but several corporations such as D-Wave (Canada) and Qucor (Australia) are developing and patenting new techniques to advance the state of the art in this area. This patent uses phosphorus nuclei as the elementary particle of a quantum computer which are embedded in a hydrogenated silicon substrate using scanning tunneling microscopy techniques.

Claim 1 reads:

1. A nanoscale product, comprising: an array of single phosphorus bearing molecules adsorbed onto a hydrogen patterned crystalline silicon surface; where the hydrogen patterned crystalline silicon surface comprises a mono layer of hydrogen from which hydrogen atoms have been singly desorbed in a controlled manner to expose less than or equal to two silicon dimers such that single phosphorous bearing molecules can adsorb to the exposed underlying silicon dangling bond site.

US Patent 7060977 - Dip Pen Nanolithography Calibration

The development of the scanning tunneling microscope, and later the atomic force microscope, in the early 1980's was a crucial development for nanotechnology since these devices allow for detection at the atomic level by using ultrasharp tips positioned by sensitive optical and piezoelectric feedback mechanisms. Together with other new microscopes such as near-field optical microscopes and magnetic force microscopes, these devices introduced a paradigm shift in microscopy by using proximal, or near contact, inspection techniques rather than the far field optical or electron beam inspection methods used previously. Collectively referred to as scanning probe microscopes these proximal probes are now beginning to revolutionize manufacture techniques, as they previously revolutionized microscopy in the '80s and '90s, by providing etching, curing, coating, or other fabrication process steps. Nanoink, the owner of this patent, is helping to lead the way in this innovation by using the tips as a nanoscale coating tool in applications such as mask repair and circuit fabrication. This patent is specific to a calibration method. Claim 1 reads:

1. A method for calibration of a scanning probe nanolithographic process, the method comprising: (i) fabricating a nanoscale test pattern by scanning probe lithography, (ii) measuring a parameter of the test pattern, (iii) calculating a calibration coefficient from the measured parameter, (iv) using the calculated calibration coefficient for forming a nanolithographic pattern by scanning probe lithography.

While I admire Nanoink's efforts and think (based on some of their other patents) that this company is making a valuable contribution to nanotechnology, I think that the attorney prosecuting this application may have been a bit overambitious and the Examiner a little too lenient in allowing this claim. Test pattern calibration is common in microlithography and extention to nanolithography tools such as scanning probes, nanoimprint stamps, etc. would have been obvious to a person of ordinary skill in the art to provide the advantage of increased accuracy of fabrication at nanometer dimensions. However, regardless of arguments about obviousness, the patent is anticipated by US Patent 6337479.

See, for example, column 2, lines 46-67 of the '479 patent.

Saturday, June 17, 2006

US Patent 7060510- Photoinduced Nanofabricaton on a Ferroelectric Substrate

Plasmonics is a new field emerging from nanotechnology. Whereas electronics deals with devices based on electron flow and photonics deals with devices based on the flow of light (i.e. photons), plasmonics is concerned with the flow of the density waves of electrons, which behave more according to the wavelike nature of light than the particulate nature of electrons. Plasmonics could lead to higher speed switching and computation and nanostructured materials are being used to extend the capabilities of plasmonic based devices. This patent deals with the fabrication of such plasmonic devices based upon a ferroelectric substrate with a particular polarization distribution that is dip coated with a solution of electrically conductive metal ions which are photoreduced to create a desired pattern of nanoparticles. Claim 1 reads:

1. A method of preparing one or more opto-electronic components by patterning nanoparticles in an arrangement that facilitates a response to optical illumination, comprising: a) applying an electric field in a patterned arrangement to at least a portion of a ferroelectric surface to induce a patterned polarization distribution of the portion of the ferroelectric surface; and b) photodepositing a plurality of nanoparticles on the portion of the ferroelectric surface having the patterned polarization distribution, at least a portion of the plurality of nanoparticles being positioned adjacent to one or more electrodes.

US Patent 7060390- Vertical Nanotube Array Anode for Lithium Battery

Nanotubes have the potential to provide increased storage efficiency for batteries. This patent uses a configurations of vertically oriented multiwall nanotubes to achieve an anode for Lithium batteries. Claim 1 reads:

1. An anode assembly for a lithium ion battery, the anode assembly comprising: a conductive substrate; and a plurality of multi-walled carbon nanotubes formed on the substrate, the multi-walled carbon nanotubes being substantially parallel to each other and substantially perpendicular to the substrate.

For patent attorneys:

During prosecution the applicant presented some claims including limitations drawn to the chemical formula Li(x)Co(y)Ni(z)O(2). However, no indication was given in the specification for the values of x, y, and z and the Patent Examiner made a 35 USC 112 1st para. rejection for lack of enablement. The attorney attempted to argue that chemists knowledgeable in the chemistry of batteries would be able to figure out appropriate ranges of x, y, and z but the Examiner was unconvinced and the attorney eventually cancelled the claims dealing with Li(x)Co(y)Ni(z)O(2).
This illustrates an important point that is highly relevant in an experimental field like nanotechnology - always give multiple examples even if you think certain aspects of the invention are obvious or within experimental reach of those of ordinary skill, and especially when you are claiming these aspects. From my experience as an Examiner from 2000-2005 I definitely saw a trend of attorneys avoiding examples or details of their client's invention (although this was less true from foreign-based patent applications). This is very bad practice and is actually encouraged by the fact that many SPEs and reviewing officials at the PTO strongly emphasize the avoidance of 35 USC 112 rejections due to the difficulty of upholding these decisions at the BPAI.

Thursday, June 15, 2006

US Patent 7060356 - Nanotube Array Fabrication Using Differing Catalytic Materials

There are a variety of techniques used for fabricating uniform arrays of vertical nanotubes, such as the use of orienting electrostatic fields during CVD or the use of anodic aluminum oxide templates. While these methods are useful in manufacturing nanotubes for some devices, such as flat panel displays, other applications require overlapping nanotubes so as to create interconnections between the nanotubes. For example, nanotube-based memory, switching, or logic systems require connections between nanotubes to be formed parallel to the substrate on which the nanotubes are grown. The inventors of this patent have developed a methodology of growing vertical nanotubes to bend in particular directions by using different catalytic growth materials with differing associated growth rates. This allows for the formation of interconnections being particular bent nanotubes. Claim 6 reads:

6. A carbon nanotube-based device comprising: a substrate; a plurality of nano-sized catalytic particles formed on the substrate; and an aligned carbon nanotube array extending from the nano-sized catalytic particles; wherein said nano-sized catalytic particles each comprise a catalyst material and at least two different catalyst-doped materials which are respectively capable of causing different rates of synthesis of the carbon nanotubes so as to adjustably define a desired direction of growth of said array.

This patent joins some other recent fundamental carbon nanotube patents emerging from China useful for upcoming device applications.

Wednesday, June 14, 2006

US Patent 7060241 - Nanotube Conductive Transparent Film

Transparent and conductive films are useful for electrostatic discharge of the windows in cathode based displays. This patent teaches the formation of such films from carbon nanotubes. It is interesting to note that there is a lot of patent activity in the use of nanotubes as the electron emitters in flat panel displays. Thus combining the invention of this patent with nanotube electron emission display technology may result in an all nanotube display system. Claim 1 reads:

1. An electrically conductive film comprising: a plurality of carbon nanotubes with an outer diameter of less than 3.5 nm wherein said film has a light transmittance of at least 60% and a surface resistance of less than about 10.sup.10 ohms/square.

Tuesday, June 13, 2006

US Patent 7060224 - Nanoscale Fabrication by Electroosmotic Solder Flow

Fabrication on the molecular or nanoscale level is usually accomplished one of two ways-"in solution" or "on substrate". "In solution" fabrication usually employs chemical synthesis and self-assembly techniques and often works on developing molecular structures or nanocrystals from basic chemistries. "On substrate" fabrication usually employs techniques familiar to the semiconductor fabrication industry and often works on developing quantum wells, quantum wires, and other nanostructures. Usually these techniques are very distinct and performed separately under very different conditions. However, to optimally exploit the molecular processing of "in solution" processes, while providing a platform for substrate level processing that is suitable for mass production, it would be useful to find a technique that combines aspects of each of these fabrication methodologies. The inventors of this patent combine aspects of chemical (such as DNA) processing via electroosmotic transport and working on substrates (such as silicon). Claim 1 reads:

1. A method for the fabrication of microscale and nanoscale devices comprising the steps of: providing a target device having at least one target electrode, providing a first component device and a fluidic medium in contact with the target device, placing the first component device relative to the target electrode through action of at least electroosmotic force from the target device to the component device, and attaching the component device to the target device, wherein the attachment step includes a solder reflow step.

Monday, June 12, 2006

US Patent 7057881 - Nanofiber Capacitor

One of the simplest electronic structures is the capacitor. Basically this circuit element includes two electrodes separated by an insulating element and is useful for constructing electrical filters, phase shifters, sensors and for performing a variety of other functions for signal processing, detection, or related applications. In some cases large values of capacitances are necessary to achieve a certain function. This may be achieved in a variety of ways including increasing the area of the electrodes used to form the capacitors. However, creating larger electrodes is counterproductive to the development of smaller scale circuitry and thus a different solution is desirable. This patent suggests the use of nanofibers on the electrodes to increase the effective surface area of the capacitor. Claim 1 reads:

1. An electric capacitor, comprising at least a first electrode surface, which electrode surface comprises a plurality of nanofibers, wherein a density of the plurality of nanofibers ranges from about 0.11 nanofiber per square micron or less to at least about 1000 nanofibers per square micron, from about 1 nanofiber per square micron or less to at least about 500 nanofibers per square micron, from about 10 nanofibers per square micron or less to at least about 250 nanofibers per square micron, or from about 50 nanofibers per square micron or less to at least about 100 nanofibers per square micron.

One bizarre thing about this claim from a legal perspective is that typically when range within a range claims are presented it causes indefiniteness resulting in a 35 USC 112 2nd para. rejection (MPEP 2173.05c).

Sunday, June 11, 2006

US Patent 7057402 - Nanotube Sensor With Integral Heater

There are numerous sensor applications for nanotubes which exploit the alteration of the current/voltage relationship of an array of nanotube formed between electrodes when exposed to gases or radiation. One of the drawbacks of such sensors is that forming nanotubes on a substrate requires high temperatures which may damage other electronic components involved in the sensing. This patent gets around this problem by using an integral heater preformed on the substrate to provide localized heating to form the nanotubes without damaging other preformed circuit components. Claim 1 reads:

1. A sensor comprising: a thermally isolated area on a substrate; a heating element proximate the thermally isolated area; a pair of conductors each having a portion adjacent a portion of the other; and a plurality of carbon nanotubes formed extending from one of the conductors to the other.

The heating element also facilitates gas sensing by driving off gas after sensing.

Saturday, June 10, 2006

US Patent 7057245 - MEMS Transferred to Second Support

There has been some discussion about the US patent office's ability to handle nanotechnology patents. In my opinion, based on my experience as a Patent Examiner, graduate studies in nanotechnology, and a review of issuing nanotech patents, the quality of examination on average (with some exceptions as noted in the previous posting) is probably slightly better for nanotech patents than other patents. The reason for this is that usually the applicants for nanotech. patents are very knowledgeable of their field and provide the Examiner with a lot of background in the form of prior art submissions, etc. Also due to the popularization of nanotechnology in the press there is probably more pressure on the Examiner to do a thorough job for these applications.

Unfortunately, the same can not be said of microelectromechanical systems (MEMS) based inventions. Due to the variety of diverse applications to which these devices may be applied (sensors, rf switches, optical relays, displays, etc.) there is no centralized resource within the US patent office for Examiners to search for broad claims directed to these devices. In addition the inventors/applicants often may have expertise in their specific field to which they are applying MEMS (rf electronics, optics, etc) but have deficient knowledge of the numerous generic teachings related to MEMS. Often patent attorneys will write the broadest possible patent claims which may fall outside of the application of the main embodiment. All of the above factors result in numerous patents in the MEMS field being issued improperly.

Case in point is this patent US 7057245, in which pre-diced MEMS components are attached to a secondary substrate so that the actuation direction of the MEMS structure can be modified from the orientation with respect to a first substrate used for the initial manufacture. Claim 1 reads:

1. An array of lithographically fabricated MEMS devices comprising: a plurality of individual dies including at least one MEMS device, each die having been separated from adjacent dies on an original fabrication wafer, with each die of the plurality positioned on a second wafer, and affixed mechanically to said second wafer.

The Examiner apparently overlooked prior art patents such as or
which employ techniques of fluidic self-assembly to assemble and adhere pre-diced MEMS components onto a secondary substrate.

US Patent 7057203 - Metal Salt Treated Nanotube Electron Emitter

As mentioned in earlier postings, numerous patents have been granted based upon technologies exploiting electron emitting nanotubes. This patent teaches employing metal salts such as ionic alkali metals (Li, Na, K, Rb, Cs, Fr) to treat the electron nanotubes and enhance the emission.
Claim 1 reads:

1. A field emission apparatus comprising: a) a low pressure gaseous environment; and b) a cathode comprising: i. a substrate; and ii. a metal salt-treated carbon nanotube layer deposited on the substrate.

This is not the first patent employing metal treated nanotubes to enhance field based electron emission in a low pressure gaseous environment (see for example It is also not the first patent to treat nanotubes with metal salts (see The attorney argued against the use of the '697 patent in an obviousness rejection since the '697 patent included an embodiment directed toward battery structures. Even though the '697 patent clearly states that the alkali metal enhancement is useful for a number of diverse applications to provide the advantage of increasing the energy efficiency of nanotubes, the examiner was successfully convinced that the '697 nanotube patent was in a different field of endeavor then the '292 nanotube patent directed towards electron emission nanotubes. This is slightly problematic since one of ordinary skill in the nanotechnology art would likely consider the combined teachings of a variety of references concerned with nanotubes in determining what was obvious, regardless of whether particular embodiments were directed to a specific application. Unfortunately it seems that many patent examiners may not recognize the existence of a person of ordinary skill in the nanotechnology art and are thus unable to formulate proper obviousness rejections in terms of one of ordinary skill in nanotechnology. With the continued reluctance of the US patent office to create a centralized group of Examiners focusing on the growing volume of nanotech. patents these types of problems are likely to increase.

Thursday, June 08, 2006

US Patent 7056758 - Manufacture of Nanotube Ribbon Memory

Currently there are three main application areas employing nanotubes- flat panel displays, which use nanotubes as electron emitters, composite materials, which use nanotubes for improvement of mechanical or electrical properties, and mechanical memory, which uses nanotubes as bit storage elements. A great deal of patent literature has been developed in the nanotube flat panel display and nanotube composite material areas, with each of these areas including overlapping claims owned by different corporations. However, the patent literature for nanotube mechanical memory is almost entirely owned by a single company called Nantero. This patent is the 19th patent Nantero has received for various aspects of this technology with many other patents pending and relates to one embodiment of a manufacturing method of the memory. Claim 1 reads:

1. A method of making electromechanical circuit elements comprising the acts of: providing a structure having electrically conductive traces and supports, the supports extending from a surface of the substrate; providing a layer of nanotubes over the supports; and selectively removing portions of the layer of nanotubes to form ribbons of nanotubes that cross the electrically conductive traces, wherein each ribbon comprises one or more nanotubes.

Wednesday, June 07, 2006

US Patent 7056479 - CVD Nanotube Fabrication On Porous Carbon Substrate

There are three basic strategies commonly employed to fabricate nanotubes-arc discharge, laser vaporization, and chemical vapor deposition (CVD). Arc discharge usually employs graphite electrodes in a low pressure, helium environment and electric breakdown between the electrodes result in a buildup of nanotube containing deposits on the negatively biased electrode. Laser vaporization usually employs laser evaporation of a graphitic sample in an argon environment resulting in nanotube containing byproducts. Both arc discharge and laser vaporization result in a mixture of nanotubes, carbon soot, and other byproducts and, while refinements of these techniques as well as purification methods have allowed for increased bulk production of nanotubes, they are not suited for producing a well ordered array of pure nanotubes on a substrate such as required for many electronics and sensor applications.

CVD, however, is capable of producing well-ordered nanotube arrays on a substrate (such as a silicon wafer or aluminum oxide template) by using catalytic particles (e.g. Ni, Co, Fe) and a flow of hydrocarbon gas at a high temperature. Unfortunately, this technique suffers from low yield and contamination of amorphous carbon. The inventors of this patent propose the use of porous carbon as the substrate on which the catalytic CVD growth of nanotubes can occur. This apparently reduces heating requirements, increases yield, and reduces contamination. Claim 1 reads:

1. A process for producing carbon nanotubes comprising the steps of: (a) depositing a metallic catalyst on a porous carbon substrate; (b) passing a feedstock gas containing a source of carbon through the substrate; and (c) applying an electrical current to said substrate to heat the substrate sufficiently to generate a reaction between said catalyst and said gas, resulting in the formation of carbon nanotubes.

Tuesday, June 06, 2006

US Patent 7056409 - Silicon Nanofiber Velcro

Many improvements have been made over the past few centuries in the art of fastening materials together, such as improvements in buttons, zippers, velcro and so on. Nanotechnology is making it's contribution to the further evolution of fastening technology. The inventors of this patent quote the desirably of adhesive attachments as found in nature (such as used by spiders, etc.) and explain the use of silicon nanofiber to achieve a bonding effect. Claim 3 reads

3. A method of adhering two or more surfaces, the method comprising: i.) providing a first surface comprising a plurality of silicon nanofibers attached thereto; ii.) providing at least a second surface; and, iii.) contacting the first surface and the at least second surface, wherein at least a portion of the plurality of nanofibers contacts the second surface on a side surface of said nanofibers wherein the contacting creates van der Waals forces between the nanofibers and the second surface which van der Waals forces are sufficient to adhere the surfaces together.

An earlier patent (US 6927982) uses other nanomaterial (carbon nanotubes) for bonding electronic circuit elements.

Monday, June 05, 2006

US Patent 7054513 - Quantum Dot Optical Fiber Sensor

The use of fiber optic waveguides in sensing operations is fairly well known. Chemical impurities, heat, or pressure on the fiber effect the transmission of light by the fiber and these effects may be exploited in environmental sensors. The inventors of this patent teach a way to form holes in optical fibers and inserting quantum dots in the holes. Quantum dots may also be used in environmental detection and can supplement or amplify the sensing effects of the optical fiber. Claim 1 reads:

1. An optical fiber sensor, comprising: a holey optical fiber comprising: a) a guiding region for carrying confined light b) a plurality of holes in the optical fiber; c) a plurality of quantum dots in the holes; and a light detector coupled to the holey optical fiber, operable for detecting a change in an optical characteristic of the quantum dots.

Sunday, June 04, 2006

US Patent 7054064 - Polarizer Using Aligned Nanotubes

Polarizing sheets are commonly used in sunglasses and LCDs to control the transmission of light. This invention uses a parallel arrangement of nanotubes to achieve a polarization sheet that absorbs light parallel to the nanotube arrangement and transmits light perpendicular thereto. Advantageously this type of polarizer may work at higher temperatures and more humid environments than conventional polarizers. Claim 17 reads:

17. An optical polarizer comprising: a support member; and an optical polarizing film supported by the support member, and comprising a plurality of carbon nanotube yarns which are compactly aligned with and substantially parallel to one another, each of the carbon nanotube yarns having substantially the same width.

US Patent 7053736 - MEMS Switch With Restoring Force Member

Micromechanical switches have some advantages over electronic switches including resistance to electrostatic shock, low leakage current, and higher power transmission. Often MEMS switches are in the form of a lever or cantilever that is bent from an open state, in which the cantilever is out of contact with an opposing electrode, to a closed state, in which the cantilever is in contact with the opposing electrode, by application of a voltage to a separate gate electrode. However, one of the problems of this configuration is that the the cantilever often sticks to the opposing electrode requiring excessive voltage for release. The inventors of this patent offer the solution of providing a second cantilever above the first to provide a restoring force and thus reducing the voltage necessary for releasing the cantilever to the open state.

The independent claims read:

1. A microelectromechanical device, comprising a beam configured to apply an opening force on a closed switch, wherein the opening force is substantially independent of a force stored in the closed switch.

6. A microelectromechanical device, comprising: a switch beam spaced above a closing gate and a contact structure; and an additional beam configured to apply a force on the switch beam in a direction away from the contact structure.

31. A method for opening a switch, comprising: reducing an attractive force between a switch beam and a closing gate; and externally applying a mechanical force on the switch beam in a direction away from the closing gate.

Reading the file history of this case I actually found a few disturbing things. First off the Examiner applied separate rejections based on two different prior art references under 35 USC 102e. The earliest of these references had a US priority date of November 9, 2001 whereas the filing date of this patent was Sept. 30, 2002. To counter these rejections the applicant provided an affidavit stating an earlier conception date prior to Sept.30,2002. However, in this affidavit the only proof of earlier reduction to practice was an Invention Disclosure Form without any signatures of the inventors or witnesses and with the conception date blacked out with a marker. I'm not sure whether this is common practice but I've never had a case like that when I was an Examiner. The rule covering swearing back a reference (37 CFR 1.131) requires a showing of facts rather than only an allegation of an earlier reduction to practice and the applicant didn't seem to provide such a showing. Nevertheless it appeared adequate to the Examiner handling this case.

Unfortunately, one of the applied anticipatory references (US 6720851) has a foreign priority date to an even earlier date so, while not applicable under 35 USC 102e I doubt the applicant could win an interference hearing.

Also unfortunately the Examiner missed even earlier anticipatory prior art such as


Saturday, June 03, 2006

US Patent 7053520 - Nanotube Rotational Motor

Microelectromechanical actuators have several applications as drivers for optical switches and microfluidic valves. However, scaling down micromechanical structures to the nanoscale presents some problems including stiction (sticking) between the microstructural elements because of residual chemicals after a wet etch. Using nanostructures such as nanotubes for nanoelectromechanical actuators has previously been suggested as a solution to this problem. This patent teaches using a multiwall nanotube as a motor with the inner tubes as a stator and an outer tube as a rotor. High rotational degree of freedom is achieved by applying a high voltage to the stator and releasing the outer tube. Claim 1 reads:

1. A nanoscale device, comprising: (a) a substrate; (b) at least one anchor pad on the substrate; (c) a multiwalled nanotube mechanically connected to and extending from the anchor pad; (d) a rotor plate connected to a rotatable wall of the nanotube and positioned to rotate in conjunction with the nanotube and relative to the substrate; and (e) at least one stator electrode connected to the substrate, and disposed about the rotor plate to electrically interact therewith when charged with suitable voltage to cause rotational movement; said multiwalled nanotube having an outer shell that is compromised in a region between the rotor and the anchor pad to permit additional rotational freedom of the rotor.

Friday, June 02, 2006

US Patent 7053034 - Nanospheres Within Microspheres For Controlled Delivery

Along the lines of the previously discussed patent, in which a core/shell structure was used to avoid reactivity between a nanoparticle and the environment, this patent provides microspheres each containing a plurality of nanospheres. The microspheres are formed of a pH sensitive material for controlled delivery of the nanospheres only under specific environmental conditions. This may be used in a variety of applications where timed or environment-specific delivery of nanoparticles is desired but interaction of the nanoparticles with the environment at earlier times or in an inappropriate enviroment needs to be avoided. Applications to hair care products and laundry detergent are cited. Claim 1 reads:

1. A controlled release composition comprising: a plurality of solid nano-spheres, each of said solid nano-spheres comprising an effective amount of a first active agent and a cationic surface active agent, said plurality of nano-spheres are formed of a hydrophobic material, said plurality of nano-spheres being encapsulated within a pH sensitive or salt sensitive micro-sphere, said pH sensitive or salt sensitive micro-sphere is formed of a pH sensitive or salt sensitive matrix material wherein each of said nano-spheres has an average size of about 0.05 to about 2 microns and said micro-sphere has a size of from about 2 microns to about 50 microns.

It is interesting to note that this is a case where, lacking the claimed ranges, the Patent Examiner rejected the claims but the addition of the claimed ranges resulted in allowability of the patent. This may not be unfounded since while it may be well known or obvious to encapsulate microparticles in larger particles, the fabrication process of nanoparticles within microspheres would require a different process.

Thursday, June 01, 2006

US Patent 7052777 - Nanoparticles With Metal Oxide Shells

A core/shell morphology is a useful way to prevent a nanoparticle (the core) from undesirably reacting with the enviroment. The inventors of this patent use metal oxide layers as shells and when the ambient temperature is raised above a sintering temperature of the shell material the shells coalesce into a binding structure for the core nanoparticles. Composite material formed by the core/shell nanoparticles may serve a variety of applications including oxygen storage/desorption and tailoring the refractive index for optical elements. Claim 1 reads:

1. A composite nanoparticle material comprising a plurality of cores and a plurality of shells, with each of the shells comprising at least one metal oxide and a second metal or metal oxide, wherein at least one of the cores is encapsulated by one of the shells and at least two of the plurality of shells are capable of being sintered together to form a reticulated network.

US Patent 7052666 - Untangling Single Walled Nanotubes By Cutting

Single Walled Carbon Nanotubes (SWNTs) are basically carbon atoms in a hexagonal lattice formed in a cylindrical shape of nanometer scale diameter. Generally carbon has four electrons for bonding but in the case of SWNTs only three of these electrons are used per carbon atom. The extra electrons cause a stickiness between SWNTs when a large concentration of the SWNTs are produced resulting in a tangled web of the SWNTs. In order to isolate individual SWNTs, this patent proposes a cutting technique (using for example a focused ion beam or oxidative etching). Claim 1 reads

1. A method for untangling single-wall carbon nanotubes comprising: a) providing tangled single-wall carbon nanotubes; b) cutting at least a portion of the single-wall carbon nanotubes to un-tangle at least some of the single-wall carbon nanotubes; and c) recovering a material comprising the single-wall carbon nanotubes un-tangled by the cutting step.

This patent is yet another in a long line of recently issued SWNT patents from Smalley's group at Rice University claiming priority from many years ago, in this case from 1996. The Examiner initially applied prior art dealing with the purification of tangled SWNTs and arguing inherency of cutting based on purification but the patent attorney successfully convinced the Examiner that the inherency was incorrect by noting that the cited purification would require a different energy input and application time to achieve the claimed cutting.