Nanotechnology – Zvi Yaniv, Richard Lee Fink, Samsung Electronics Co Ltd

Abstract for “Alignment carbon nanotubes”

“Carbon nanotubes can be aligned in a host phase that contains molecules that align under a certain pressure. The host molecules align themselves so that the carbon nanotube fibres align in the same direction. After the film of aligned nanotubes has dried, it can be polished to form a thin layer of common-aligned carbon nanotube fibres that can be used in a field emission device.

Background for “Alignment carbon nanotubes”

“Carbon nanotubes have shown good electron field emission. The prior art however, shows that the carbon nanotubes are not deposited in a well-organized manner on the cathode. FIG. FIG. 1 shows such a cathode 100 having a substrate 101 as well as an electrode 102. The carbon nanotubes 103 are shown deposited on electrode102 in these disorganized positions. The electron emission efficiency is affected by the disorganized nature of carbon nanotube fibers.

“There is therefore a need for an art to align such carbon nanotubes in order to increase the efficiency of electron emission.”

The present invention solves the above need by providing a method to align carbon nanotubes within a host layer. After the carbon nanotubes have been aligned, the host phases is subject to a binding process that makes the carbon nanotubes’ alignment permanent. The host phase’s surfaces can be polished, resulting in carbon nanotubes that are substantially vertically aligned within a thin film. This can then be used to create a field emission device including a display, within a cathode.

“The above has provided a broad overview of the technical features and benefits of the present invention to make it easier for you to understand the detailed description of this invention which will be given in detail. These features and advantages form the subject matter of the patent claims.”

“The following description contains many specific details, such as host phases and display structures. This description is intended to give a complete understanding of the invention. It will be apparent to those skilled in art that the present invention can be used without requiring such detailed information. Other cases, well-known circuits are shown in block diagram form to avoid obscure the invention.

“Refer to the drawings, where elements depicted are not always shown at scale. Similar elements are identified by the same reference number through all views.

The present invention takes advantage of the fact that carbon nanotubes can be placed in a host phase of ordered, elongated particle. These ordered elongated particles can be liquid crystals, metal fibers placed in liquids under an electric or magnetic field, geometrically anizotropic particles, and anizotropic crystals (elongated), possessing strong dipole moments. The present invention allows the user to choose the size of carbon nanotube fibers relative to the host phase. This aligns the host phase’s particles with the carbon nanotube fibers.

“Referring FIGS. “Referring to FIGS. As discussed further below, the liquid crystal may also contain an ultraviolet (UV-curable) binder. This hardens it when exposed to UV light. Alternately, the host phase could be an arrangement of elongated crystals within an isotropic liquid media (oil). A long chain of polymer molecules linked together by mechanical means such as rubbing would also be an alternative host phase. This is called rubbing. This is a common process in liquid crystal art. This rubbing process will be further explained below. The carbon nanotubes (204) are placed within the host phase (step 701), and will initially be aligned with one another (not shown). This is similar to FIG. 1. This is done between the electrodes 202 & 203 in a container (not illustrated). While electrode 203 is grounded, electrode 202 is connected to a power source. Consider that the liquid crystal molecules in this example are both long and heavy (about 500 angstroms). A field of 50-60V will align the host molecules (205) and the nanotubes (204) if the nanotubes are 50 micrometers long.

“An alternative is to deposit a substrate at the bottom 200 of the hostphase and above the electrode203 so that the substrate acts as a host phase for the nanotubes.

“Another way to align the host phase is by placing it in contact with an alignment layer (as illustrated in FIG. 8. The alignment layer 802, which may contain long-chain polymers in semi-solid form, is deposited on substrate 801. It can then be rubbed or combed in one direction in order to align the polymers in the specified direction. The alignment layer 802 and the host phase 803 physically contact each other to align the molecules in the desired direction. This direction is dependent on many parameters. The alignment of the host phases in the desired direction results in alignment of nanotubes within them.”

“As mentioned previously, the host can contain an ultraviolet (UV-curable binder 302 or other curable monomers for example, heat. The process results in a solid layer of aligned carbon-nanotubes 204 by shining ultraviolet light on the phase 301. This is called binding the alignment (step 703).

The solid film can then be cut along the dashed lines A, B and/or one or several of the polished surfaces (step 704) to create a thin 400-nanotube-organized film that can be used for cold electron sources for field emission applications. The carbon nanotubes will 204 emit electrons from their ends 401 once an electric field has been created.

Referring to FIG. “Referring to FIG. Because the nanotubes are made from a more durable carbon or graphic material, this is possible. This will expose a portion of the 902. You should also know that the etching step is possible in conjunction with, or alternatively to, the polishing process.

FIG. 10 shows an alternative process for etching. FIG. 10 shows an alternative etching process. This involves using a mask (not illustrated) to selectively etch wells 1003 in the host phase 1001 and selected carbon nanotubes 1002. The result is that exposed portions of the 1002 nanotubes are again seen.

FIG. 12 shows an alternative embodiment of the invention. 12. The nanotubes 1202 can be contacted on the bottom by a conductive coating 1205 On the top side, a conductive layer 1204 has been deposited. The wells 1203 are then etched into the top-side conductive layer 1204 or the host phase 1201. This allows the top conductive 1204 to be electrically isolated from nanotubes 1202. The top conducting layer 1204 is then used to control the gate.

“Exposed carbon nanotubes above their host phase can lead to a greater emission of electrons.

“An alternative to putting a conductive coating on the bottom host phase, a 1103 conductive layer can be placed on top 1101 of the host Phase 1101. After an etching process that exposes portions of the 1102 nanotubes 1102. The conductive layer is used to generate the electric field necessary for the emission of electrons from carbon nanotubes 1102.

“Alternatively, you can dope the host phase of any of the above embodiments to make it conducting or semiconducting. This eliminates the need for a conductor layer.”

“This is further demonstrated by the field emission device 500, FIG. 5. An anode 502 is composed of an electrode 503, a phosphor 503 and a substrate 502. The cathode 505 is made up of a substrate 506, an electro 503 and a phosphor 504. The carbon nanotubes emit electrons when an electric field is applied. Optionally, any number of extraction grids 508, 509 or gate electrodes may be used.

“A field emission device 500 is able to be used for many purposes, including to produce single cathode pixels elements to create large billboard-like displays or smaller displays such that can be used by computers. The cathodes can also be aligned in strips to make a matrix-addressable screen.

“FIG. “FIG. 6 shows a data processing device 613 that uses a display device made of the field emission devices. 5 shows a typical hardware configuration for workstation 613 according to the subject invention. It includes a central processing unit (CPU), 610, which can be a conventional microprocessor and a variety of other units connected via system bus 612. Workstation 613 has random access memory 614, read-only memory 616 and an input/output adapter 618 to connect peripheral devices like disk units 620, tape drives 640, and keyboard 624 and mouse 626 to bus 612. User interface adapter 622 can be used to connect keyboard 624 and mouse 626 to bus 612. Communication adapter 634 is used to connect workstation 613 with a data processing network. Display adapter 636 is used to connect bus 612 to display device 638 to display adapter Other circuitry may be included in CPU 610, as well as circuitry that is not shown herein. This includes circuitry common to microprocessors, such as execution unit, bus interface units, and arithmetic logic units. A single integrated circuit may contain CPU 610.

“Even though the advantages of the present invention have been explained in detail, it is important to understand that many modifications, substitutions, and alterations may be made without departing from its spirit and scope as described by the attached claims.”

Summary for “Alignment carbon nanotubes”

“Carbon nanotubes have shown good electron field emission. The prior art however, shows that the carbon nanotubes are not deposited in a well-organized manner on the cathode. FIG. FIG. 1 shows such a cathode 100 having a substrate 101 as well as an electrode 102. The carbon nanotubes 103 are shown deposited on electrode102 in these disorganized positions. The electron emission efficiency is affected by the disorganized nature of carbon nanotube fibers.

“There is therefore a need for an art to align such carbon nanotubes in order to increase the efficiency of electron emission.”

The present invention solves the above need by providing a method to align carbon nanotubes within a host layer. After the carbon nanotubes have been aligned, the host phases is subject to a binding process that makes the carbon nanotubes’ alignment permanent. The host phase’s surfaces can be polished, resulting in carbon nanotubes that are substantially vertically aligned within a thin film. This can then be used to create a field emission device including a display, within a cathode.

“The above has provided a broad overview of the technical features and benefits of the present invention to make it easier for you to understand the detailed description of this invention which will be given in detail. These features and advantages form the subject matter of the patent claims.”

“The following description contains many specific details, such as host phases and display structures. This description is intended to give a complete understanding of the invention. It will be apparent to those skilled in art that the present invention can be used without requiring such detailed information. Other cases, well-known circuits are shown in block diagram form to avoid obscure the invention.

“Refer to the drawings, where elements depicted are not always shown at scale. Similar elements are identified by the same reference number through all views.

The present invention takes advantage of the fact that carbon nanotubes can be placed in a host phase of ordered, elongated particle. These ordered elongated particles can be liquid crystals, metal fibers placed in liquids under an electric or magnetic field, geometrically anizotropic particles, and anizotropic crystals (elongated), possessing strong dipole moments. The present invention allows the user to choose the size of carbon nanotube fibers relative to the host phase. This aligns the host phase’s particles with the carbon nanotube fibers.

“Referring FIGS. “Referring to FIGS. As discussed further below, the liquid crystal may also contain an ultraviolet (UV-curable) binder. This hardens it when exposed to UV light. Alternately, the host phase could be an arrangement of elongated crystals within an isotropic liquid media (oil). A long chain of polymer molecules linked together by mechanical means such as rubbing would also be an alternative host phase. This is called rubbing. This is a common process in liquid crystal art. This rubbing process will be further explained below. The carbon nanotubes (204) are placed within the host phase (step 701), and will initially be aligned with one another (not shown). This is similar to FIG. 1. This is done between the electrodes 202 & 203 in a container (not illustrated). While electrode 203 is grounded, electrode 202 is connected to a power source. Consider that the liquid crystal molecules in this example are both long and heavy (about 500 angstroms). A field of 50-60V will align the host molecules (205) and the nanotubes (204) if the nanotubes are 50 micrometers long.

“An alternative is to deposit a substrate at the bottom 200 of the hostphase and above the electrode203 so that the substrate acts as a host phase for the nanotubes.

“Another way to align the host phase is by placing it in contact with an alignment layer (as illustrated in FIG. 8. The alignment layer 802, which may contain long-chain polymers in semi-solid form, is deposited on substrate 801. It can then be rubbed or combed in one direction in order to align the polymers in the specified direction. The alignment layer 802 and the host phase 803 physically contact each other to align the molecules in the desired direction. This direction is dependent on many parameters. The alignment of the host phases in the desired direction results in alignment of nanotubes within them.”

“As mentioned previously, the host can contain an ultraviolet (UV-curable binder 302 or other curable monomers for example, heat. The process results in a solid layer of aligned carbon-nanotubes 204 by shining ultraviolet light on the phase 301. This is called binding the alignment (step 703).

The solid film can then be cut along the dashed lines A, B and/or one or several of the polished surfaces (step 704) to create a thin 400-nanotube-organized film that can be used for cold electron sources for field emission applications. The carbon nanotubes will 204 emit electrons from their ends 401 once an electric field has been created.

Referring to FIG. “Referring to FIG. Because the nanotubes are made from a more durable carbon or graphic material, this is possible. This will expose a portion of the 902. You should also know that the etching step is possible in conjunction with, or alternatively to, the polishing process.

FIG. 10 shows an alternative process for etching. FIG. 10 shows an alternative etching process. This involves using a mask (not illustrated) to selectively etch wells 1003 in the host phase 1001 and selected carbon nanotubes 1002. The result is that exposed portions of the 1002 nanotubes are again seen.

FIG. 12 shows an alternative embodiment of the invention. 12. The nanotubes 1202 can be contacted on the bottom by a conductive coating 1205 On the top side, a conductive layer 1204 has been deposited. The wells 1203 are then etched into the top-side conductive layer 1204 or the host phase 1201. This allows the top conductive 1204 to be electrically isolated from nanotubes 1202. The top conducting layer 1204 is then used to control the gate.

“Exposed carbon nanotubes above their host phase can lead to a greater emission of electrons.

“An alternative to putting a conductive coating on the bottom host phase, a 1103 conductive layer can be placed on top 1101 of the host Phase 1101. After an etching process that exposes portions of the 1102 nanotubes 1102. The conductive layer is used to generate the electric field necessary for the emission of electrons from carbon nanotubes 1102.

“Alternatively, you can dope the host phase of any of the above embodiments to make it conducting or semiconducting. This eliminates the need for a conductor layer.”

“This is further demonstrated by the field emission device 500, FIG. 5. An anode 502 is composed of an electrode 503, a phosphor 503 and a substrate 502. The cathode 505 is made up of a substrate 506, an electro 503 and a phosphor 504. The carbon nanotubes emit electrons when an electric field is applied. Optionally, any number of extraction grids 508, 509 or gate electrodes may be used.

“A field emission device 500 is able to be used for many purposes, including to produce single cathode pixels elements to create large billboard-like displays or smaller displays such that can be used by computers. The cathodes can also be aligned in strips to make a matrix-addressable screen.

“FIG. “FIG. 6 shows a data processing device 613 that uses a display device made of the field emission devices. 5 shows a typical hardware configuration for workstation 613 according to the subject invention. It includes a central processing unit (CPU), 610, which can be a conventional microprocessor and a variety of other units connected via system bus 612. Workstation 613 has random access memory 614, read-only memory 616 and an input/output adapter 618 to connect peripheral devices like disk units 620, tape drives 640, and keyboard 624 and mouse 626 to bus 612. User interface adapter 622 can be used to connect keyboard 624 and mouse 626 to bus 612. Communication adapter 634 is used to connect workstation 613 with a data processing network. Display adapter 636 is used to connect bus 612 to display device 638 to display adapter Other circuitry may be included in CPU 610, as well as circuitry that is not shown herein. This includes circuitry common to microprocessors, such as execution unit, bus interface units, and arithmetic logic units. A single integrated circuit may contain CPU 610.

“Even though the advantages of the present invention have been explained in detail, it is important to understand that many modifications, substitutions, and alterations may be made without departing from its spirit and scope as described by the attached claims.”

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