US Patent 7988893 - Fabricating CNT yarn

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This patent from Hon Hai Precision (Foxconn) is the latest in a series of patents disclosing manufacturing of longer yarn-like structures from carbon nanotube material useful for increasing the mechanical and electrical properties of cables, printed circuit boards, cloths, and other macroscopic articles. Claim 1 reads:

1. A method for fabricating a carbon nanotube yarn, the method comprising:

(a) providing a plurality of carbon nanotube arrays;

(b) pulling out a first carbon nanotube structure from one of the plurality of carbon nanotube arrays;

(c) pulling out a subsequent carbon nanotube structure from another one of the plurality of carbon nanotube arrays;

(d) joining a leading end of the subsequent carbon nanotube structure to a trailing portion of the first carbon nanotube structure by contacting the leading end of the subsequent carbon nanotube structure with the trailing portion of the first carbon nanotube structure, thereby forming a lengthened carbon nanotube structure; and

(f) treating the lengthened carbon nanotube structure with an organic solvent.

US Patent 7973295 - Method for making transparent carbon nanotube film

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This patent from Hon Hai Precision (Foxconn) includes some basic claims for a method of manufacturing transparent electrodes from carbon nanotube film. Claim 1 reads:

1. A method for making a transparent carbon nanotube film, the method comprises the following steps:

(a) obtaining a carbon nanotube film; and

(b) irradiating the carbon nanotube film by a laser device with a power density greater than 0.1×104 W/m2.

US Patent 7932477 - Electron beam heating with CNTs

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One of the most commonly proposed application of carbon nanotubes is as electron emission devices which can be applied to displays, sensors, and maskless lithography. This patent from Hon Hai Precision (Foxconn) teaches how carbon nanotube strings can also form field emitters for heating. Claim 1 reads:

1. An electron beam heating system comprising:

a cathode;

an anode; and

a carbon nanotube string, wherein the carbon nanotube string comprises an end portion and an emission portion, the end portion is in direct electrical contact with the cathode, the carbon nanotube string is composed of a plurality of carbon nanotube bundles packed closely, each of the carbon nanotube bundles comprises a plurality of carbon nanotubes, the carbon nanotubes are substantially parallel to each other and are joined by van der Waals attractive force, the emission portion comprises a plurality of carbon nanotube bundles forming a tooth-shaped structure;

a chamber, wherein the cathode, the anode and the carbon nanotube string are located in the chamber.

US Patent 7757371 - Nanostructured reference leak

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A reference leak is an instrument used as a calibration standard for detecting gas leaks. This patent from Hon Hai Precision teaches a nanostructured version of a reference leak which is less sensitive to temperature variations. Claim 1 reads:

1. A method for making a reference leak, comprising the steps of:

(a) preparing a substrate;

(b) forming a patterned catalyst layer on the substrate, the patterned catalyst layer comprising one or more catalyst blocks, each catalyst block being located at a respective chosen position on the substrate;

(c) forming one or more elongate nano-structures so as to extend from the corresponding catalyst blocks by a deposition method;

(d) forming a leak layer of one of a metallic material, a glass material, a composite material, and a ceramic material on the substrate, the one or more elongate nano-structures being thereby partly or completely embedded within the formed leak layer; and

(e) removing the one or more elongate nano-structures and the substrate to obtain a reference leak with one or more leak holes defined therein, each leak hole being defined by a space previously occupied by a respective one elongate nano-structure.

US Patent 7749477 - Tracking CNT growth

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In CVD growth of carbon nanotube arrays the nanotubes usually grow from catalytic particles in a root-growth or a tip-growth fashion. During root-growth the catalyst remains on the substrate while during tip growth the catalyst particle remains on the tip of the nanotube during growth. In order to study these different growth modes and other aspects of nanotube formation researchers at Hon Hai Precision and Tsinghua University have implements an intermittent CVD method in which line markings form on the nanotubes to track their growth. Claim 1 reads:

1. A carbon nanotube array comprising:

a plurality of carbon nanotubes; and

at least one line mark formed on the carbon nanotubes, the at least one line mark transversely extending across the carbon nanotubes;

wherein the at least one line mark comprises a plurality of line marks transversely extending across the carbon nanotubes;

wherein the line marks are parallel to each other; and

wherein the line marks are nonuniformly-spaced.

US Patent 7745302 - TEM grid using CNTs

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Transmission electron microscopy is one of the most important techniques for the examination of nanoscale structures. This patent from Hon Hai Precision teaches a way to enhancing the electrical conductivity and strength of TEM grids by using carbon nanotubes. Claim 1 reads:

1. A method for making a transmission electron microscope (TEM) grid comprising:

providing an array of carbon nanotubes, a substrate, and a plurality of metal girds attached on the substrate;

drawing one or more carbon nanotube films from the array of carbon nanotubes;

covering the substrate with one or more carbon nanotube films;

treating the one or more carbon nanotube films with organic solvent; and

irradiating a portion of the one or more carbon nanotube films between every two adjacent metal girds,

further comprising stacking two or more carbon nanotube films and using the two or more carbon nanotube films to cover the grids;

wherein the angle between the aligned directions of the stacked carbon nanotube films ranges from 0 to about 90 degrees.

US Patent 7744956 - CNT patterning to eliminate shielding effects

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High efficiency electron emitters may be manufactured by growing arrays of carbon nanotubes in a high density however there is an ultimate limit to the efficiency determined by a screening effect in which electrostatic repulsion effects come into play when the array density is too high. This patent from Hon Hai Precision teaches a way around this problem based on a patterned segmentation within the nanotube arrays. Claim 1 reads:

1. A method for forming a patterned array of carbon nanotubes, the method comprising the steps of:

(a) forming an array of carbon nanotubes on a substrate; and

(b) exerting a pressure on the array of carbon nanotubes by a molding device having a pattern to imprint the array of carbon nanotubes to obtain the patterned array of carbon nanotubes;

wherein the molding device is a metal wire mesh.

US Patent 7741765 - CNT field emitter with support wire

http://www.freepatentsonline.com/7741765.html

Chemical vapor deposition is a common technique used to manufacture electron emitting devices based on carbon nanotubes. One deficiency in this method is that electrically induced mechanical stress can weaken the connection between the nanotubes and a cathode on which the nanotubes are grown. This patent from Hon Hai Precision teaches an alternative arrangement based on carbon nanotube yarn twisted around a cathode wire. Claim 1 reads:

1. A field emission element comprising:

at least one supporting wire; and

at least one carbon nanotube wire, the at least one carbon nanotube wire and the at least one supporting wire are twisted together,

a conductive cathode electrode, wherein the supporting wire is electrically fixed on the conductive cathode electrode and comprised of a material different from that of the at least one carbon nanotube wire.

US Patent 7713589 - Improved CVD nanotube fabrication

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Chemical vapor deposition is a technique used to grow carbon nanotubes from catalytic particles by exposing the catalysts to hydrocarbon gases at high temperatures. This patent from Hon Hai Precision teaches a way to lower the temperature of CVD nanotube growth while improving the speed and yield of growth. Claim 1 reads:

1. A method for making an array of carbon nanotubes, comprising the steps of:

(a) providing a substrate with a film of catalyst provided thereon;

(b) disposing the substrate in a reaction chamber;

(c) supplying a carrier gas into the reaction chamber and heating the reaction chamber to a predetermined temperature; and

(d) introducing a carbon source gas and a hydrogen gas into the reaction chamber separately and simultaneously;

the hydrogen gas being introduced such that the hydrogen gas has less of a distance to travel in the reaction chamber than does the carbon source gas to reach the substrate.

US Patent 7710649 - CNT optical polarizer

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This patent is from Hon Hai Precision and teaches the fabrication of carbon nanotube films used as optical polarizers for LCDs. Claim 1 reads:

1. An optical polarizer, comprising:

a supporting member; and

a polarizing film supported by the supporting member, the polarizing film comprises a plurality of layers of carbon nanotube films stacked on each other, and the layers of carbon nanotube films are secured to one another by van de Waals attractive force, each carbon nanotube film being comprised of a plurality of carbon nanotubes, the carbon nanotubes in a given carbon nanotube film all being aligned in a same direction.

US Patent 7625530 - Manufacture of isotope-doped CNTs

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Isotope labeling is a technique used to study nanoscale growth mechanisms. This patent from Tsinghua University and Hon Hai Precision teaches an arc discharge method using isotope doping to study the growth process. Claim 1 reads:

1. A method for manufacturing isotope doped carbon nanotubes, comprising the steps of:

(a) providing a carbon rod connected with an anode of an electrical source, the carbon rod comprising at least two kinds of carbon isotope segments arranged alternately along a longitudinal direction of the carbon rod;

(b) providing a pure carbon rod connected with a cathode of the electrical source, the pure carbon rod positioned corresponding to the carbon rod; and

(c) producing an arc discharge between the carbon rod and the pure carbon rod, the carbon isotope segments of the carbon rod being consumed in sequence to form the isotope doped carbon nanotubes.