Process and device for upgrading current emission
a current emission and process technology, applied in the field of current emission devices, can solve the problems of inability to meet the needs of advanced skill, long operating time period, and inability to meet the needs of current emission, and achieve the effects of reducing voltage level, working better, and reducing capacity
Inactive Publication Date: 2007-02-22
NATIONAL TSING HUA UNIVERSITY
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Benefits of technology
[0010] It is therefore an object of the present invention to provide a process applied to a current emitting device composed of material including carbon, for the current emitting device to be capable of working better with a display screen, particularly a display on a mobile or compact apparatus, or those on an apparatus with power source limited to lower voltage level or lower capacity.
[0011] It is therefore another object of the present invention to provide a process applied to an object composed of material including carbon, for the object to work better with a display.
[0013] Another further object of the present invention is to provide a current emitting device easily made to be capable of working better with a display, particularly a display on a mobile or compact apparatus, or those on an apparatus with power source limited to lower voltage level or lower capacity.
[0020] For a current emitting device composed of material including carbon, the cause of changing in shape to be capable of emitting electrons of higher density under the same or lower onset emission voltage, is the cleavage of some C═C double bonds of carbon therein. The process according to the present invention is the unique art so far to cause the cleavage of C═C double bonds in a current emitting device composed of material including carbon, for the current emitting device to work better with a display, or to be capable of emitting larger current under the same or lower onset emission voltage. Therefore another still further aspect of the present invention is represented by a process applied to a current emitting device composed of material including carbon, to split the C═C double bonds of the current emitting device, so that the current emission capability of the current emitting device improves, i.e., the current emitting device becomes capable of emitting current of higher density under the same or lower onset emission voltage.
[0022] U.S. Pat. No. 6,250,984 suggests that nanotubes with depressed tips will enhance electron emission. In contrast, either a depression or a tip on the surface of a nanotube oxidized according to the present invention will upgrade the current emission capability of the nanotube, regardless of the location of the depression or the tip on the surface of the nanotube, and regardless of the feature of the surface of the nanotube and the shape of the nanotube (the nanotube may be in the shape of a tube or in the shape of a ball or in any other shape according to the present invention). U.S. Pat. No. 6,250,984 does not suggest nanotubes with surface having oxygenated group thereon.
[0024] US Patent Application 2003 / 0143398 disclosed an art in which use of oxygen plasma is suggested for etching the tip of nanotube to have the tip opened for improving the field emission characteristics of the nanotube. In contrast, the carbon nanotube according to the present invention is oxidized by using O2, or O3, or CO2, or NO2, or SO2, or SO3 to have a depression or a tip formed on the exposed portion (or surface) of the nanotube for upgrading the current emission capability of the nanotube.
Problems solved by technology
An apparatus requiring lower operating voltage (due to lower onset emission voltage for emitting electrons to drive the display screen) consumes less energy, resulting in longer operating time period on the basis of the same battery capacity.
However wishfilly a carbon nanotube is used as a current emitting device, it suffers from its incapability of emitting sufficient electrons to drive a display screen under a realizable onset emission voltage.
Although the attempt achieves low onset emission voltages, the required process includes peeling off and reversing an array or film of nanotubes, which requires sophisticated skill and is difficult to implement, particularly when commercializtion of a product is concerned.
Method used
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[0035] In FIG. 1, a carbon nanotube's exposed portion 11 has an end part 12 and can be used as a current emitting device to emit electrons. For example, an array of carbon nanotubes' exposed portions 11 may be used to emit electrons for driving a display screen (not shown in figures), i.e., the emitted electrons collide with a display screen to form images on the display screen. The carbon nanotube's exposed portion 11 may be regarded as having another end part 13 on or connecting a substrate or carrier (not shown in figures), or regarded as being grown from a substrate.
[0036]FIG. 2 shows a view of a carbon nanotube's exposed portion 21 which has been oxidized according to the present invention to have its end part 22 changed in shape. For example, at least a part 23 of end part 22 becomes depressed, and at least a part 24 thereof turns to be in the shape of a tip or similar to the shape of a tip, thereby the current emission capability of the carbon nanotube improves and / or the on...
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Abstract
An art is provided to realize a current emitting device capable of emitting current of higher density under the same or lower onset emission voltage. The current emitting device is preferably an array of carbon nanotubes or a film including carbon nanotubes. The art is based on using O2, and / or O3, and / or CO2, and / or NO2, and / or SO2, and / or SO3 to oxidize a current emitting device composed of material including carbon, until the current emitting device has at least part thereof changed in shape. The current emitting device thus processed works better with a display, or becomes capable of emitting current of higher density under the same or lower onset emission voltage. As far as experiments showed, the emitted current density achieved by the art can be eight times the amount emitted by an array of nanotubes having not been processed according to the art, and the onset emission voltage can be lowered by the art from 0.8 V / μm to 0.5 V / μm.
Description
CROSS REFERENCE TO RELATED APPLICATION [0001] This is a continuation-in-part of prior, pending application Ser. No. 10 / 313,757, filed on Dec. 5, 2002.FIELD OF THE INVENTION [0002] The present invention generally relates to a current emitting device, and particularly to a carbon nanotube used for emitting electrons, and to a process applied thereto. BACKGROUND OF THE INVENTION [0003] Pretty much effort has been made by many to explore or discover new schemes for emitting electrons to drive a display screen or another device. This is particularly crucial when application of a display to a mobile apparatus becomes popular and size minimiion of apparatus including a display is eagerly expected. The most significant one among the new schemes explored or discovered for his purpose is to have a current emitting device easily made to be of smaller size while being capable of emitting electrons for driving a display screen, without need of higher onset emission voltage or even with lower ons...
Claims
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Login to View More IPC IPC(8): D01F9/12B29C57/00B29C71/02H01J9/02
CPCB82Y10/00B82Y30/00H01J9/025H01J2201/30469H01J9/02C01B32/168
InventorHWANG, KUO-CHU
OwnerNATIONAL TSING HUA UNIVERSITY