IL166173A - Field emission cold cathode - Google Patents
Field emission cold cathodeInfo
- Publication number
- IL166173A IL166173A IL166173A IL16617305A IL166173A IL 166173 A IL166173 A IL 166173A IL 166173 A IL166173 A IL 166173A IL 16617305 A IL16617305 A IL 16617305A IL 166173 A IL166173 A IL 166173A
- Authority
- IL
- Israel
- Prior art keywords
- cathode
- velvet material
- fibers
- cold cathode
- cesiated salt
- Prior art date
Links
- 239000000463 material Substances 0.000 claims description 57
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 54
- 229910052799 carbon Inorganic materials 0.000 claims description 51
- 150000003839 salts Chemical class 0.000 claims description 43
- 239000000835 fiber Substances 0.000 claims description 41
- 239000000243 solution Substances 0.000 claims description 20
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 12
- 238000000034 method Methods 0.000 claims description 12
- 239000008367 deionised water Substances 0.000 claims description 11
- 239000012266 salt solution Substances 0.000 claims description 9
- 239000011248 coating agent Substances 0.000 claims description 6
- 238000000576 coating method Methods 0.000 claims description 6
- 229910052757 nitrogen Inorganic materials 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 6
- 238000000151 deposition Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- LYQFWZFBNBDLEO-UHFFFAOYSA-M caesium bromide Chemical compound [Br-].[Cs+] LYQFWZFBNBDLEO-UHFFFAOYSA-M 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 4
- 239000013078 crystal Substances 0.000 claims description 4
- GLYAPCVEOALCSB-UHFFFAOYSA-L dicesium;tellurate Chemical compound [Cs+].[Cs+].[O-][Te]([O-])(=O)=O GLYAPCVEOALCSB-UHFFFAOYSA-L 0.000 claims description 4
- 239000004593 Epoxy Substances 0.000 claims description 3
- XQPRBTXUXXVTKB-UHFFFAOYSA-M caesium iodide Chemical compound [I-].[Cs+] XQPRBTXUXXVTKB-UHFFFAOYSA-M 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims description 3
- 238000013022 venting Methods 0.000 claims description 3
- 230000008021 deposition Effects 0.000 claims description 2
- 238000001704 evaporation Methods 0.000 claims 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 9
- 239000004917 carbon fiber Substances 0.000 description 8
- 230000003247 decreasing effect Effects 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 239000004744 fabric Substances 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229920001651 Cyanoacrylate Polymers 0.000 description 1
- MWCLLHOVUTZFKS-UHFFFAOYSA-N Methyl cyanoacrylate Chemical compound COC(=O)C(=C)C#N MWCLLHOVUTZFKS-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000010943 off-gassing Methods 0.000 description 1
- 238000012552 review Methods 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/30—Cold cathodes, e.g. field-emissive cathode
- H01J1/304—Field-emissive cathodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
- H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2201/00—Electrodes common to discharge tubes
- H01J2201/30—Cold cathodes
- H01J2201/304—Field emission cathodes
- H01J2201/30446—Field emission cathodes characterised by the emitter material
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Cold Cathode And The Manufacture (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Description
166173/2 166173 I 453587 WW Field Emission Cold Cathode 166173/4 TECHNICAL FIELD The invention is in the field of vacuum tubes, and more particularly relates to a field emission cold cathode acting as an electron emitter in a vacuum tube.
BACKGROUND ART Cathodes are electron emitters used in a wide variety of vacuum tubes, such as cathode ray tubes used in televisions and various microwaves tubes used in radar and communications. All of these cathodes must be kept under a high vacuum and heated to a very high temperature, i.e., at least 900 °C for proper operation. High vacuum necessitates the use of special manufacturing techniques, such as having a device that is sealed, as well as extensive baking out procedures. Further, these types of cathodes are susceptible to combination if the cathode is removed from vacuum. The high vacuum thus gives rise to considerable restrictions associates with tube handling, operation, and storage.
The requirement for high temperature operation creates several significant design constraints. Firstly, the high temperature requires the use of special materials able to withstand the high temperature operation of the cathode. In addition, the heater reduces energy efficiency and increases system volume, weight, and complexity.
Accordingly, there is a need for a cathode that can operate at low temperatures with less stringent vacuum requirements, while delivering the same electron emission.
Gerate E. Et al., "Novel cathode for field-emission applications", Review of Scientific Instruments, American Institute of Physics, New York, US, Vol. 66, No. 3, pp. 2528-2532 (March 1995) disclosed inter alia Csl salt-based Cathode which is capable of producing a modest preveance, 10 s of A/cm2 electron beam for several microseconds pulse lengths, and has little susceptibility to diode closure has been experimentally characterized. More particularly, this publication discloses a field emission cold cathode using either velvet cloth or carbon fibers as the cathode emissive material. The carbon fiber cathodes are constructed by drilling an array of uniformly spaced holes in a graphite disk, then threading carbon fiber through the holes and securing them to the rear of the graphite disk using quick-setting epoxy.
The graphite disk is then adhered to an aluminum cathode backing plate with cyanoacrylate. A saturated solution of csi is applied using a fine brush to the emissive surface of the cathode, i.e., either the carbon fibers or the velvet cloth. The emissive surface is then dried and baked. The publication shows only fibers having uniform lengths.
H. Kosai et al., "Long pulse csi impregnated field emission cathodes", Review of Scientific Instruments, American Institute of Physics, New York, Vol. 61 , No.7, pp. 1880-1882 (July 1990). This reference discloses attaching either graphite fibers or a velvet cloth to a solid graphite cathode. An aqueous solution of csi is applied to the cathode surface and allowed to dry, depositing a layer of salt thereon. Attaching either of the aforementioned materials improves performance, and further improvement is obtained by applying a coating of csi. The publication makes no reference to the lengths of the fibers.
Y. E. Krasik et al., "Emission properties of different cathodes at E< 105 V/cm" ournal of Applied Physics, American Institute of Physics, New York, Vol.89, No. 4, pp. 23792399 (Feb 2001). This publication discloses cathodes for generating high-current electron beams, made of metal-ceramic, carbon fibers, carbon fabric, velvet or corduroy.
It further discloses coating the carbon fibers and carbon fabric with a Csi solution. While the length of the fibers varies from material to material, the length of the fibers for each material is uniform, i.e., there is no disclosure of a singular material having fibers of nonuniform lengths.
DISCLOSURE OF INVENTION The present invention relates to a field emission cold cathode characterized by a cathode; a carbon velvet material attached to the cathode; and the carbon velvet material including fibers having nonuniform lengths and having a cesiated salt deposited thereon.
The present invention addresses the aforementioned shortcomings of the prior art by providing a field emission cold cathode that operates at cold temperatures and at a lower vacuum than the field emission cathodes of the prior art. Thus, the present invention relates to a field emission cold cathode characterized by a cathode; a carbon velvet material attached to the cathode; and the carbon velvet material including fibers having nonuniform lengths and having a cesiated salt deposited thereon. More particularly, the 1A invention includes a carbon velvet material comprised of high aspect ratio carbon fibers perpendicularly embedded in a base material. The carbon velvet material Is attached to a cathode. A cesiated salt is deposited on the fibers. Electrons are emitted when a sufficient voltage is applied to the cathode.
A second aspect of the invention provides a method for making a field emission cathode comprising forming a solution of a cesiated salt, coating a carbon velvet material with the solution, and bonding the material to a cathode. The third aspect of the invention provides a method for making a field emission cold cathode comprising depositing a vaporized cesiated salt solution onto the fibers of a carbon velvet material, forming cesiated salt crystals on the fibers, and bonding the carbon velvet material to a cathode.
A fourth aspect of the invention provides a method for coating a carbon velvet material attached to a cathode to make a field emission cold cathode, comprising spraying the material with a solution of cesiated salt and de-ionlzed water; baking the coated carbon velvet material at a temperature of at least 100 °C for approximately an hour in a vacuum oven evacuated to less that 1 tonr., and then venting the vacuum oven to an atmospheric pressure using dry nitrogen.
A fifth aspect of the invention provides a method for making a field emission cold cathode by forming a film of cesiated salt having a thickness of 1 angstrom to 10 microns on each of a plurality of fibers of a carbon velvet material, and bonding the carbon velvet material to a cathode. A sixth aspect of the invention provides making a field emission cold cathode by attaching a carbon velvet material having fibers to a cathode, immersing the fibers In a molten cesiated salt solution, and cooling the solution while the fibers are immersed in the solution. A seventh aspect of the invention provides for making a field emission cold cathode by attaching a carbon velvet material having fibers to a cathode, immersing the fibers in a molten cesiated salt solution, removing the fibers from the solution, and cooling the fibers.
Conventional vacuum tubes require a hjgh vacuum and a cathode element that must be heated to at least 900 °C for proper operation. Although the term "cold- cathode" refers to a cathode that operates at or near room temperature, as well as to cathodes that operate at temperatures below 900 °C, the cold cathode of the present invention operates at room temperature and thus eliminates the heating and high operating temperature requirements of the prior art. It also operates at a lower vacuum level than the cathodes of the prior art. The cold cathode of the present invention can 2 166173/2 WO 2004/010450 PCT/US20O2/O21283 replace, with attendant advantages, the heated cathode of any type of vacuum tube, including, klystrons, traveling wave tubes, magnetrons, magnlcons, and Wystrode/IOT television transmitters.
Other aspects and advantages of the cold cathode of the present Invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawing, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWING The figure is a schematic of the laboratory setup used to test the field emission cold cathode of the present invention, and includes a cross-section of the field emission cold cathode of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION The figure Is a schematic drawing of the laboratory setup used to test field emission cold cathode 11 of the present invention, and shows a cross section of cold cathode 11. The setup includes vacuum chamber 13 and cathode mounting 7. Shaft ,19 protrudes Into vacuum chamber 13, and can be retracted and extended relative to cold cathode 1 . Anode 21 is mounted on the end of shaft 19. Gap 23 Is the distance separating cathode 11 and anode 21, and Is adjustable by means of retracting or extending shaft 19.
Cold cathode 1 1s comprised of high voltage bushing 24, carbon velvet material 25, and cathode surface 27. As will subsequently be described in detail, carbon velvet material 25 is treated with a low work function ceslated salt and bonded to cathode surface 27. Carbon velvet materia! 25 consists of high aspect embedded perpendicular to a base material?]¾cpar?cuMn ilterial Black® applique, a proprietary product of Energy Science Laboratories, Inc. Vel-Black® applique consists of high aspect ratio carbon fibers mounted In an adhesive base, and was developed for its optical characteristics, I.e., as a black applique for ultra-low reflectance and for stray-light suppression In optical systems.
Carbon velvet material 25 is flexible and can be readily bonded to any shape of cold cathode 11. A conductive epoxy can be used to bond carbon velvet material 25 to cathode surface 27 where cathode surface 27 Is metallic. Alternatively, pyrobonding can be used to bond carbon velvet materia! 25 to a carbon substrate. Cold electron emission is obtained by forming cesiated salt crystals on the tips of the fibers of carbon 3 velvet material 25, as well as by depositing a film having a thickness of 1 angstrom to 10 microns on the fiber shafts.
To coat only the fiber shafts of carbon velvet material 25, a mask to which the ceslated salt cannot become attached Is applied to the fiber tips. The mask Is removed be etching after the cesiated salt Is applied to the fibers.
The low work function ceslated salt can be deposited on the carbon velvet material 25 by several different methods. Two of the methods employ a solution of highly purified ceslated salt and de-Ionized water as the medium for ceslated salt deposition. More particularly, cesiated salt is first mixed with de-ionized water. Carbon velvet material 25 Is then sprayed with the cesiated salt solution using an atomizer. Grade five dry nitrogen Is used to provide the backpressure for the atomizer. Two to four coats are applied. Cold cathode 11 is then placed in a vacuum oven, evacuated to less than 1 torr., baked at a sufficient temperature and duration to evaporate th€$ de-ionized water (over 00 °C for approximately an hour), and then vented to atmospheric pressure using grade five dry nitrogen.
A number of low work function cesiated salts can be used, including cesium iodide (Csl), cesium tellurate (CsTe04), and cesium bromide (CsBr). While a single cycle will improve cathode performance and reduce out-gassing, additional cycles will further improve the operational performance of cold cathode 11. However, improvement is obtained only up to a point, whereupon additional cycles will increase the required turn-on field, i.e., the electric field level at which the electrons begin to flow from cathode 11 to anode 21.
Alternatively, the fibers of carbon velvet material 25 can be dipped Into the ceslated salt solution. The assembly comprised of cold cathode and the solution bath is then baked to approximately 00 °C at atmospheric pressure until the solution crystallizes on the tips and/or the shafts of carbon velvet material 25. At this stage, cold cathode 1 is withdrawn from the bath and baked in a vacuum oven to evaporate any remaining water from the tips and/or the shafts. The vacuum oven Is then vented to the atmosphere using dry nitrogen.
In another alternative, the cesiated salt can be deposited on the fibers of carbon velvet material 25 by dipping cold cathode 11 into a crucible of molten cesiated salt so that the fibers are submerged. The molten cesiated salt Is then allowed to cool with the fibers still submerged, until the cesiated salt crystallizes on the tips and/or the shafts. Cesiated salt can also be deposited on the tips and/or the shafts of carbon velvet 4 166173/2 Υν'Ο 2004/010450 PCT US2002/021283 material 25 by chemical vapor deposition such that the ceslated salt crystals form on the tips and/or the shafts. Each of these processes is more expensive and time consuming than using the de-ionized water solution of cesiated salt. However, each results in a more uniform coating of the cesiated salt, and neither requires baking cold cathode 11 to remove excess water vapor.
When negative voltage Is applied to cold cathode 11, electrons are emitted from the cathode surface 27, accelerated through anode-cathode gap 23, and then impinge anode 21. The turn-on field has been as low as 0.2 kV/cm. This is far less than the typical turn-on fields of conventional vacuum tubes. The voltage source may be pulsed or continuous. Cold cathode 11 can have any shape, e.g., spherical, cylindrical, or planar. .Anode-cathode gap 23 can be any interaction region or other region In which emitted electrons are used. Cold cathode 11 is preferably operated in a vacuum of at least 10'3 torr. Anode 21 can be any region or structure that collects emitted electrons.
The turn-on field of cold cathode 11 can be varied In several ways to suit the requirements of the device in which it is to be used. With respect to carbon velvet material 25, a longer, narrower fiber tip and a lower tuft density permit greater field enhancements at the fiber tips and hence reduce the turn-on field for cold cathode 11. It has also been found that a distribution of fiber lengths tends to reduce the turn-on filed.
The turn-on field can also be varied by changing the density of cesiated salt in solution with de-ionized water and by varying the number of coats applied to the tips and shafts of the carbon fibers, i.e., increasing the density or the number of coats (up to a point) decreases the tum-on field. For example, In some microwave tubes it is desirable to not have electrons flow until the voltage reaches Its full value. This can be accomplished by increasing the tuft density as well as by decreasing the amount of cesiated salt applied, either by the decreasing the number of coats or by decreasing the density of the cesiated salt in solution with de-Ionized water. 6 166173/5 ■ ^
Claims (15)
1. . A field emission cold cathode characterized by: a cathode; a carbon velvet material attached to the cathode; and the ' carbon velvet material including fibers having nonuniform lengths and having a cesiated salt deposited thereon.
2. The cold cathode of claim 1 , characterized in that: each fiber is comprised of a shaft and a tip; and the cesiated salt is deposited either on the tips or on the shafts.
3. The cold cathode of claim 1 , characterized in that the cesiated salt is deposited on the tips and on the shafts.
4. The cold cathode of claim 2 or 3, characterized in that the deposition of the cesiated salt comprises a film having a thickness of 1 angstrom to 10 microns.
5. The cold cathode of any one of claims 1 to 4, characterized in "that the cesiated salt is a low work function cesiated salt, and/or in that the cesiated salt is selected from the group consisting of cesium iodide/ cesium tellurate and cesium bromide, and/or in that the carbon velvet material is Vel-Black® applique.
6. The cold cathode of any one of claims 1 to 5, characterized in that the cathode is operated in a vacuum of at least 10"3 torr.
7. The cold cathode of any one of claims 1 to 6, characterized in that: the cathode includes a metallic surface; and the carbon Velvet material is bonded to the surface with a conductive epoxy, ;or'in that: the cathode includes a carbon substrate; and the 'carbon velvet material is attached to the cathode by means of pyrobohding with the substrate. 7 166173/5
8. The cold cathode of any one of claims 1 to 7, further characterized by: ; means for spraying a solution of the cesiated salt and de-ionized water onto the carbon velvet material, and means for baking the cathode at a temperature of at least 100°C in a vacuum of less than 1 torr. for a period sufficient to remove the de-ionized water, fronri the carbon velvet material, whereby the cesiated salt is crystallized and deposited on the fibers.
9. A method for coating a carbon velvet material attached to a cathode according to any one of Claims 1 through 7 to make a field emission cold cathode, characterized by: forming a solution of a low work function cesiated salt and de-ionized water; spraying the carbon velvet material with the cesiated salt solution to form a coated carbon velvet material; baking the coated carbon velvet material at a temperature of at least 1,00°C for approximately an hour in a vacuum oven evacuated to less than 1 torr. ; and venting.;! the vacuum oven to an atmospheric pressure using dry nitrogen.
10. The , method of claim 9, characterized in that the spraying step includes pressurizing a spraying means with dry nitrogen, and/or in that the cesiated salt is selected from the group consisting of cesium iodide, cesium tellurate and cesium bromide, and/or in that the steps of forming, spraying, baking; and venting are repeated until a film of cesiated salt having a thickness of 1 angstrom to 10 microns is formed on a plurality of fibers of the carbon velvet material.
11. 1 1. A method of making a field emission cold cathode according to any one of Claims 1 through 7, characterized by: forming a solution of a cesiated salt; 8 166173/5 coating a carbon velvet material with the cesiated salt solution; and f; bonding the carbon velvet material to a cathode.
12. A method of making a field emission cold cathode according to any one of Claims 1 through 7, characterized by: depositing a vaporized cesiated salt solution onto fibers of a carbon velvet material; forming cesiated salt crystals on the fibers; and bonding the carbon velvet material to a cathode.
13. The method of claim 12, characterized in that the solution includes de-ionized water and the forming step is comprised of evaporating the de-ionized water.
14. A method of making a field emission cold cathode according to any one of Claims 1 through 7, characterized by: forming ap film of cesiated salt having a thickness of 1 angstrom to 10 microns on a plurality of fibers of a carbon velvet material; and bonding the carbon velvet material to a cathode.
15. A method of making a field emission cold cathode according to any one of Claims 1 through 7, characterized by: attaching a carbon velvet material having fibers to a cathode; ·' ■ 4 ^r immersing the fibers in a molten cesiated salt solution; and : cooling the solution while the fibers are immersed in the solution, or removing the fibers from the solution; and cooling the fibers. FOR THE APPLICANT Dr. Yitzhak Hess & Partners
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/US2002/021283 WO2004010450A1 (en) | 2002-07-18 | 2002-07-18 | Field emission cold cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| IL166173A0 IL166173A0 (en) | 2006-01-15 |
| IL166173A true IL166173A (en) | 2012-02-29 |
Family
ID=30769013
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IL166173A IL166173A (en) | 2002-07-18 | 2005-01-06 | Field emission cold cathode |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP1523751A1 (en) |
| JP (1) | JP4295215B2 (en) |
| CN (2) | CN100508100C (en) |
| AU (1) | AU2002322392B2 (en) |
| BR (1) | BR0215809A (en) |
| CA (1) | CA2492853C (en) |
| EA (1) | EA009410B1 (en) |
| IL (1) | IL166173A (en) |
| WO (1) | WO2004010450A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2487433C1 (en) * | 2011-12-29 | 2013-07-10 | Открытое акционерное общество "Центральный научно-исследовательский институт "Электрон" | Cathode pack of vacuum tube for high-voltage operation |
| CN107385376B (en) * | 2017-08-04 | 2019-07-19 | 华中科技大学 | A kind of spray caesium device |
| CN115863124A (en) * | 2022-12-08 | 2023-03-28 | 潍坊德森威尔电气有限公司 | An audio vacuum tube using nano-carbon fiber hot wire |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6091186A (en) * | 1996-11-13 | 2000-07-18 | The Board Of Trustees Of The Leland Stanford Junior University | Carbon-containing cathodes for enhanced electron emission |
| JP3610325B2 (en) * | 2000-09-01 | 2005-01-12 | キヤノン株式会社 | Electron emitting device, electron source, and method of manufacturing image forming apparatus |
-
2002
- 2002-07-18 WO PCT/US2002/021283 patent/WO2004010450A1/en not_active Ceased
- 2002-07-18 CN CNB02829338XA patent/CN100508100C/en not_active Expired - Fee Related
- 2002-07-18 BR BRPI0215809-4A patent/BR0215809A/en not_active IP Right Cessation
- 2002-07-18 CN CN2009101289003A patent/CN101527238B/en not_active Expired - Fee Related
- 2002-07-18 AU AU2002322392A patent/AU2002322392B2/en not_active Ceased
- 2002-07-18 CA CA002492853A patent/CA2492853C/en not_active Expired - Fee Related
- 2002-07-18 EP EP02756381A patent/EP1523751A1/en not_active Withdrawn
- 2002-07-18 JP JP2004522905A patent/JP4295215B2/en not_active Expired - Fee Related
- 2002-07-18 EA EA200500228A patent/EA009410B1/en not_active IP Right Cessation
-
2005
- 2005-01-06 IL IL166173A patent/IL166173A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| EA009410B1 (en) | 2007-12-28 |
| CA2492853C (en) | 2009-03-31 |
| CN100508100C (en) | 2009-07-01 |
| CA2492853A1 (en) | 2004-01-29 |
| BR0215809A (en) | 2007-03-20 |
| IL166173A0 (en) | 2006-01-15 |
| AU2002322392B2 (en) | 2009-05-28 |
| WO2004010450A1 (en) | 2004-01-29 |
| EA200500228A1 (en) | 2005-08-25 |
| CN101527238B (en) | 2011-07-13 |
| CN1639821A (en) | 2005-07-13 |
| AU2002322392A2 (en) | 2004-02-09 |
| AU2002322392A1 (en) | 2004-02-09 |
| EP1523751A1 (en) | 2005-04-20 |
| JP2005533356A (en) | 2005-11-04 |
| JP4295215B2 (en) | 2009-07-15 |
| CN101527238A (en) | 2009-09-09 |
| HK1135794A1 (en) | 2010-06-11 |
| HK1078678A1 (en) | 2006-03-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FF | Patent granted | ||
| MM9K | Patent not in force due to non-payment of renewal fees |