Emissive Type Patents (Class 445/51)
  • Patent number: 5679043
    Abstract: A matrix addressable flat panel display includes a flat cathode operable for emitting electrons to an anode when an electric field is produced across the surface of the flat cathode by two electrodes placed on each side of the flat cathode. The flat cathode may consist of a cermet or amorphic diamond or some other combination of a conducting material and an insulating material such as a low effective work function material. The electric field produced causes electrons to hop on the surface of the cathode at the conducting-insulating interfaces. An electric field produced between the anode and the cathode causes these electrons to bombard a phosphor layer on the anode.
    Type: Grant
    Filed: June 1, 1995
    Date of Patent: October 21, 1997
    Assignees: Microelectronics and Computer Technology Corporation, SI Diamond Technology, Inc.
    Inventor: Nalin Kumar
  • Patent number: 5674100
    Abstract: An electron-emitting device comprises a pair of oppositely disposed electrodes and an electroconductive film inclusive of an electron-emitting region arranged between the electrodes. The electric resistance of the electroconductive film is reduced after forming the electron-emitting region in the course of manufacturing the electron-emitting device.
    Type: Grant
    Filed: July 28, 1994
    Date of Patent: October 7, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takeo Ono, Hisaaki Kawade, Yoshinobu Sekiguchi, Yasuhiro Hamamoto, Keisuke Yamamoto, Takeo Tsukamoto, Masato Yamanobe
  • Patent number: 5669802
    Abstract: A microelectronic light-emitting device (10) is made with dual lateral thin-film emitters (35 and 40) substantially parallel to a substrate (20). A region containing phosphor (50) extends between the two emitters and contacts them. A fabrication process is specially adapted to produce the light-emitting devices and/or arrays of light-emitting devices. The process allows the use of conductive or insulating base or starting substrates.
    Type: Grant
    Filed: October 30, 1995
    Date of Patent: September 23, 1997
    Assignee: Advanced Vision Technologies, Inc.
    Inventor: Michael D. Potter
  • Patent number: 5662815
    Abstract: A multiple micro-tip field emission device is fabricated by forming a titanium adhesion layer under a striped tungsten cathode, etching the tungsten cathode radially using an aluminum mask and selectively etching the titanium adhesion layer, so that multiple micro-tips are formed due to the intrinsic internal stress of the tungsten itself. Thereby, the adjustment of the tip size is optionally available during the process and has excellent reproducibility since the process uses the intrinsic internal stress of the tungsten and the characteristic of a buffered oxide etching (BOE) method. Also, the output current can be controlled in a wide range from nA to mA because of the multiple micro-tips. By forming the tips with tungsten, the device has good strength, oxidation characteristics and work function and has good electrical, chemical and mechanical endurance.
    Type: Grant
    Filed: July 31, 1995
    Date of Patent: September 2, 1997
    Assignee: Samsung Display Devices Co., Ltd.
    Inventor: Jong-min Kim
  • Patent number: 5656330
    Abstract: A resistive element is provided which is used on a cathode conductor side of a field emission type fluorescent display device and made of a hydrogenated amorphous silicon film. Nitride is added during deposition of the hydrogenated amorphous silicon film containing an impurity for controlling resistivity of the film. A method for producing the resistive element and an apparatus therefor are also disclosed.
    Type: Grant
    Filed: March 22, 1995
    Date of Patent: August 12, 1997
    Assignee: Futaba Denshi Kogyo K.K.
    Inventors: Takahiro Niiyama, Shigeo Itoh, Teruo Watanabe
  • Patent number: 5656886
    Abstract: Cold cathode passive matrix FEDs are fabricated by depositing a resistive layer on a substrate, and coated with a protective layer in which at least one hole is formed. Cathode material is deposited on the protective layer making direct contact with the resistive layer through the hole to form bases for the emitter tips which are subsequently etched from the cathode layer. The protective layer allows overetching of the cathode material to prevent tip-to-tip electrical shorts without attacking the underlying resistive layer.
    Type: Grant
    Filed: December 29, 1995
    Date of Patent: August 12, 1997
    Assignee: Micron Display Technology, Inc.
    Inventors: Michael J. Westphal, Behnam Moradi
  • Patent number: 5651898
    Abstract: A field emission cold cathode comprises a conductive substrate, an insulating layer formed on the substrate and having plural cavities each for receiving an emitter, a gate electrode for applying a high electric field to the tips of emitters. An annular portion of the gate electrode each defining an opening overlapping corresponding cavity is located at a distance from the substrate smaller than the distance between another portion of the gate electrode and the substrate. Parasitic capacitance between the gate electrode and the cold cathode including the substrate and the emitter is reduced due to the large distance between the another portion of the gate electrode and the substrate. Between the another portion and the substrate, a second insulating layer or a gap is disposed. The field emission is cold cathode can function in a high frequency range while fabricating conical emitters with a small height due to the small distance between the annular portions and the substrate.
    Type: Grant
    Filed: November 21, 1995
    Date of Patent: July 29, 1997
    Assignee: NEC Corporation
    Inventor: Hironori Imura
  • Patent number: 5652474
    Abstract: A cold cathode is formed by providing a body of semiconductor having a surface including at least one projection and subjecting the surface to anodic etching to produce thereon a porous layer.
    Type: Grant
    Filed: February 3, 1995
    Date of Patent: July 29, 1997
    Assignee: British Technology Group Limited
    Inventors: Peter Richard Wilshaw, Emily Boswell
  • Patent number: 5645462
    Abstract: An electron-emitting device having a electron-emitting portion between electrodes on a substrate comprises a region A and a region B, the region A being electrically connected through the region B to at least one of the electrodes, electric conductivity .sigma..sub.1 of the material mainly constituting the region A and electric conductivity of the material .sigma..sub.2 mainly constituting the region B being in the relation of .sigma..sub.1 >.sigma..sub.2, and the region A being the electron-emitting portion. An electron beam-generating apparatus and image-forming apparatus comprise the electron-emitting device and a modulation means for modulating the electron beams emitted from the electron-emitting elements in accordance with information signals.
    Type: Grant
    Filed: January 24, 1996
    Date of Patent: July 8, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yoshikazu Banno, Ichiro Nomura, Hidetoshi Suzuki, Takashi Noma, Rie Ueno
  • Patent number: 5637539
    Abstract: A fabrication process for vacuum microelectronic devices having multiple electrode levels includes production of a first-level electrode mask on a substrate. The mask pattern is transferred to the substrate to produce a trench surrounding an emitter which is formed by thermal oxidation. The trench is filled with tungsten to form a gate electrode surrounding the emitter, and the resulting wafer is planarized. A second-level electrode is formed on the top surface of the wafer, and is planarized. Additional levels are similarly produced, and thereafter the electrodes are released.
    Type: Grant
    Filed: January 16, 1996
    Date of Patent: June 10, 1997
    Assignee: Cornell Research Foundation, Inc.
    Inventors: Wolfgang Hofmann, Liang-Yuh Chen, Noel C. MacDonald
  • Patent number: 5627111
    Abstract: An electron emitting device causes electron emission by a current supply in a coarse resistor film. The coarse thin resistor film is composed at least of a coarse thin silicon film.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: May 6, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takeo Tsukamoto, Akira Shimizu, Akira Suzuki, Masao Sugata, Isamu Shimoda, Masahiko Okunuki
  • Patent number: 5614784
    Abstract: The lifetime of cold-start fluorescent lamps is increased, and the ability to withstand repeated ON-OFF switching cycles enhanced by coating the electrodes with an emitter which consists of barium oxide and a small portion of metallic barium and, optionally, up to 20 mol-% of strontium oxide and a small portion of metallic strontium, preferably only up to about 5 mol-% of strontium oxide--metallic strontium. To make the emitter, barium carbonate, optionally mixed with strontium carbonate, is applied in paste form to the electrodes which, when coated, are introduced into an envelope and sealed therein. The envelope is then evacuated, and the electrodes are heated,thus converting the barium carbonate to barium oxide and metallic barium, and the strontium carbonate, if present, to strontium oxide and metallic strontium, so that the electrodes will be coated with barium oxide, optionally strontium oxide, and metallic barium and optionally metallic strontium.
    Type: Grant
    Filed: June 15, 1995
    Date of Patent: March 25, 1997
    Assignee: Patent-Treuhand-Gesellschaft fur elektrische Gluhlampen mbH
    Inventors: Christian Harzig, Roland Hoffmann, Erolf Weinhardt
  • Patent number: 5608283
    Abstract: In one electron-emitting device, non-insulating particle bonding material (24) securely bonds electron-emissive carbon-containing particles (22) to an underlying non-insulating region (12). The carbon in each carbon-containing particle is in the form of diamond, graphite, amorphous carbon, or/and silicon carbide. In another electron-emitting device, electron-emissive pillars (22/28) overlie a non-insulating region (12). Each pillar is formed with an electron-emissive particle (22) and an underlying non-insulating pedestal (28).
    Type: Grant
    Filed: June 29, 1994
    Date of Patent: March 4, 1997
    Assignee: Candescent Technologies Corporation
    Inventors: Jonathan C. Twichell, George R. Brandes, Michael W. Geis, John M. Macaulay, Robert M. Duboc, Jr., Christopher J. Curtin
  • Patent number: 5605483
    Abstract: An electron source is constituted of a substrate, and an electron-emitting element provided on the substrate. The electron-emitting element comprises a plurality of electrode pairs having an electroconductive film between each of the electrode pairs. An electron-emitting region is formed on the electroconductive film of selected ones of the electrode pairs. A method of testing the electrode pairs and/or the thin film for a defect and then generating an electron-emitting region so as to have no defect is available.
    Type: Grant
    Filed: May 26, 1995
    Date of Patent: February 25, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Toshihiko Takeda, Ichiro Nomura, Hidetoshi Suzuki, Yoshikazu Banno, Tetsuya Kaneko
  • Patent number: 5599749
    Abstract: A method of manufacturing an electric field emission type device. A recess having a tapered surface at an upper portion of the recess is provided. A sacrificial film is deposited on the substrate with the tapered recess. A sharp cusp is therefore formed on the surface of the sacrificial film over the recess. An electron emitting material film is deposited on the sacrificial film to form a fine emitter with a sharp tip. This fine emitter is exposed by etching and removing unnecessary regions under the fine emitter. This manufacturing method realizes a high performance electric field emission type device having an emitter tip with a small radius of curvature and a small apex angle.
    Type: Grant
    Filed: October 18, 1995
    Date of Patent: February 4, 1997
    Assignee: Yamaha Corporation
    Inventor: Atsuo Hattori
  • Patent number: 5597338
    Abstract: A surface-conductive electron beam source having a fine particle film which is formed by repeating a film formation step of applying and calcining an organic metal compound solution several times. A pair of electrodes come in contact with the fine particle film, and an electron-emitting portion is formed at a part of the fine particle film. There is also a display device having the electron beam source, a modulation means for modulating an electron beam emitted from the electron beam source in accordance with an information signal, and an image-forming member for forming an image by the irradiation of the electron beam.
    Type: Grant
    Filed: September 25, 1995
    Date of Patent: January 28, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kumi Iwai, Ichiro Nomura, Tetsuya Kaneko
  • Patent number: 5593335
    Abstract: A method of manufacturing an electron source having a plurality of surface-conduction electron-emitting devices arranged on a substrate in row and column directions includes the forming of electron emission portions of the plurality of surface-conduction electron-emitting devices. The forming is carried out by supplying current through the plurality of surface-conduction electron-emitting devices upon dividing them into a plurality of groups. An image forming apparatus passes a current through a plurality of electron sources, which are formed on a substrate and arrayed in the form of a matrix, in dependence upon an image signal, and an image is formed by a light emission in response to electrons emitted from the plurality of electron sources.
    Type: Grant
    Filed: April 5, 1994
    Date of Patent: January 14, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Hidetoshi Suzuki, Yoshiyuki Osada, Ichiro Nomura, Takeo Ono, Hisaaki Kawade, Eiji Yamaguchi, Toshihiko Takeda, Hiroaki Toshima, Yasuhiro Hamamoto, Tatsuya Iwasaki, Aoji Isono, Noritake Suzuki, Yasuyuki Todokoro, Masahiro Okuda, Katsuhiko Shinjo
  • Patent number: 5591061
    Abstract: An electron-emitting device has a pair of device electrodes and an electroconductive thin film including an electron emitting region arranged between the electrodes. The device is manufactured via an activation process for increasing the emission current of the device. The activation process includes steps of a) applying a voltage (Vact) to the electroconductive thin film having a gap section under initial conditions, b) detecting the electric performance of the electroconductive thin film and c) modifying, if necessary, the initial conditions as a function of the detected electric performance of the electroconductive thin film.
    Type: Grant
    Filed: July 7, 1995
    Date of Patent: January 7, 1997
    Assignee: Canon Kabushiki Kaisha
    Inventors: Sotomitsu Ikeda, Masato Yamanobe, Hisaaki Kawade, Toshikazu Ohnishi, Tatsuya Iwasaki
  • Patent number: 5580291
    Abstract: In a method for manufacturing a glow cathode for an electron tube, a layer of an alloy, such as iridium-lanthanum (Ir.sub.2 La), is produced on a substrate by coating the substrate, such as in a number of layers, with the components of the alloy by deposition from the vapor phase, such that the components of the alloy are present in the stoichiometrically correct ratio on the substrate, and in that the substrate is heated for a time duration adequate for alloy formation to a temperature that is lower than the melting temperature of the phase of the alloy having the lowest melting point.
    Type: Grant
    Filed: June 22, 1995
    Date of Patent: December 3, 1996
    Assignee: Siemens Aktiengesellschaft
    Inventors: Thomas Redel, Clemens Fiebiger
  • Patent number: 5572041
    Abstract: A field emission cathode device comprising a semiconductor substrate, a semiconductor cathode electrode layer, emitter tips formed on the cathode electrode layer to emit electrons therefrom, and a gate electrode layer formed on an insulating layer. Each of the emitter tips is arranged in the aligned apertures of the gate electrode layer and the insulating layer. To electrically isolate two adjacent cathode electrode lines from each other, the cathode electrode layer is made of a semiconductor having a conductivity type different from that of the substrate. Alternatively, the cathode electrode is made of a semiconductor having the same conductivity type as that of the substrate, and in this case, a portion between two adjacent cathode electrode lines is made of a heavily doped semiconductor so as to electrically isolate two adjacent cathode electrodes.
    Type: Grant
    Filed: September 16, 1993
    Date of Patent: November 5, 1996
    Assignee: Fujitsu Limited
    Inventors: Keiichi Betsui, Osamu Toyoda, Shin'ya Fukuta
  • Patent number: 5550431
    Abstract: An electron emitting, barium hafnate material for arc discharge lamp electrodes is manufactured by the method comprising the steps of: forming a mixture of barium carbonate and hafnium oxide in a 48 to 52 mole ratio; adding the mixture to a suitable carrier to form a slurry; ball milling the slurry for about 2 hours to form a powder mix; drying the powder mix; firing the dried powder mix in air at about 1500.degree. C. for about 22 hours to produce a product; and vibration milling the product in methanol with zirconia media to produce the barium hafnate. The latter material is then preferably vacuum impregnated into a tungsten electrode and hydrogen fired to produce a single phase barium oxide/hafnium oxide compound.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: August 27, 1996
    Assignee: Osram Sylvania Inc.
    Inventors: George L. Duggan, David A. Goodman
  • Patent number: 5507675
    Abstract: A method of manufacturing a thermionic cathode structure comprises the steps of: (1) forming a mixture of (a) tungsten powder, (b) at least one of the group comprising alumina or zirconia or yttrium oxide powder, (c) alkaline earth metal carbonate powder, and (d) a binder, (2) pressing the mixture isostatically causing the mixture to adhere to form an electrically insulating body, (3) sintering the body in a dry hydrogen ambient thereby reducing the carbonate, and (4) coating the surface of the body or a portion of the surface with a poly-crystalline metal layer.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: April 16, 1996
    Assignee: Thorn Microwave Devices Limited
    Inventor: Michael S. Frost
  • Patent number: 5470265
    Abstract: A multi-electron source has a plurality of electron emitting portions arranged on a substrate. Each electron emitting portion comprises a conductive film containing a crack with an average width of 0.05 .mu.m to 1 .mu.m. The electron emitting portions are prepared by subjecting conductive films, preferably of fine particles, to a pulse voltage application treatment.
    Type: Grant
    Filed: January 28, 1993
    Date of Patent: November 28, 1995
    Assignee: Canon Kabushiki Kaisha
    Inventors: Ichiro Nomura, Yoshikazu Banno, Tetsuya Kaneko, Toshihiko Takeda, Kumi Iwai
  • Patent number: 5451175
    Abstract: An electronic device including a plurality of field emission devices exhibiting dis-similar electron emission characteristics wherein an aperture radius associated with each of the plurality of field emission devices determines the electron emission characteristic.
    Type: Grant
    Filed: January 6, 1994
    Date of Patent: September 19, 1995
    Assignee: Motorola, Inc.
    Inventors: Robert T. Smith, Robert C. Kane
  • Patent number: 5430300
    Abstract: A low voltage vacuum field emission device and method for manufacturing is provided. The devices are fabricated by anodizing a heavily doped silicon wafer substrate (12) in concentrated HF solution, forming extremely sharp silicon tips (18) at the silicon to porous silicon interface. The resulting porous silicon layer is then oxidized, and a metal film (22) is deposited by evaporation on the porous silicon. Silicon substrate (12) is the cathode, and metal film dots (22) are the anodes. The I-V characteristics for the field emission devices follow Fowler-Nordheim curves over three decades of current. The I-V characteristics are also utterly independent of temperature up to 250.degree. C. When the oxidized porous silicon layer (OPSL) is about 5000 .ANG., substantial current is obtained with less than 10 volts. Recent experiments leave no doubt that the charge transport is in the vacuum of the pores.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: July 4, 1995
    Assignee: The Texas A&M University System
    Inventors: Wing K. Yue, Donald L. Parker, Mark H. Weichold
  • Patent number: 5417600
    Abstract: A manufacturing method of an impregnation type cathode for removing emitter material remaining on the porous sintered body pellets, includes steps for impregnating the emitter material into void spaces between the porous sintered body pellets, heating a phosphoric compound in a vessel up to the temperature in a range of about 100.degree. C. to about 300.degree. C., and dipping the impregnated emitter material into the heated phosphoric compound. The manufacturing method of the present invention creates a cathode which operates stably for a long time with high current density because there is no damage caused when the remaining emitter material is removed from the surface of the porous sintered body pellets.
    Type: Grant
    Filed: January 22, 1993
    Date of Patent: May 23, 1995
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takeyuki Maegawa, Yoshio Takada
  • Patent number: 5399238
    Abstract: A method of making sub-micron low work function field emission tips without using photolithography. The method includes physical vapor deposition of randomly located discrete nuclei to form a discontinuous etch mask. In one embodiment an etch is applied to low work function material covered by randomly located nuclei to form emission tips in the low work function material. In another embodiment an etch is applied to base material covered by randomly located nuclei to form tips in the base material which are then coated with low work function material to form emission tips. Diamond is the preferred low work function material.
    Type: Grant
    Filed: April 22, 1994
    Date of Patent: March 21, 1995
    Assignees: Microelectronics and Computer Technology Corporation, SI Diamond Technology, Inc.
    Inventor: Nalin Kumar
  • Patent number: 5394006
    Abstract: A method of forming a self-aligned gated field emitter with reduced gate opening and uniform gate height, on a substrate, is described. A field emitter is formed on the substrate. A thin, conformal dielectric layer is formed over the field emitter and the substrate. A thick dielectric layer is formed over the thin, conformal dielectric layer. The thick dielectric layer is planarized. The thick dielectric layer is etched back. A conductive layer is formed over the thick dielectric layer. The conductive layer is planarized and then etched back. The field emitter is exposed by forming an opening in the conductive layer, by removing the portion of the thin, conformal dielectric layer above and around the top of the field emitter.
    Type: Grant
    Filed: January 4, 1994
    Date of Patent: February 28, 1995
    Assignee: Industrial Technology Research Institute
    Inventor: David N.-C. Liu
  • Patent number: 5391259
    Abstract: A method for forming a substantially uniform array of atomically sharp emitter tips, comprising: patterning a substrate with a mask, thereby defining an array; isotropically etching the array to form pointed tips; and removing the mask when substantially all of the tips have become sharp. A mask having a composition and dimensions which enable the mask to remain balanced on the apex of the tips until all of the tips are of substantially the same shape is used to form the array of substantially uniform tips.
    Type: Grant
    Filed: January 21, 1994
    Date of Patent: February 21, 1995
    Assignee: Micron Technology, Inc.
    Inventors: David A. Cathey, Kevin Tjaden
  • Patent number: 5391433
    Abstract: A carbon material for electrodes which is a graphite/glass like carbon composite material having a structure in which the crystals of the graphite are oriented in one direction in the matrix of the glass like carbon so as to possess an electrode reaction activity inherent in the graphite crystals, having a maximum pore diameter of 150 .ANG. or less, and having electrolyte non-penetrative properties substantially corresponding to those of the glass like carbon; and a process for preparing a carbon material for electrodes which comprises the steps of highly dispersing, composing and orienting a graphite fine powder of the sufficiently grown crystals in an organic substance which can leave a glass like and less graphitizable carbon when calcined in a non-oxidizing atmosphere, and then calcining and carbonizing the composition.
    Type: Grant
    Filed: November 4, 1992
    Date of Patent: February 21, 1995
    Assignee: Mitsubishi Pencil Kabushiki Kaisha
    Inventors: Takamasa Kawakubo, Yoshihisa Suda
  • Patent number: 5391101
    Abstract: A method of manufacturing a low noise microchannel plate which limits feedback includes creating a conductive layer on the output side of the microchannel plate so that portions of the open areas in the output end are closed off.
    Type: Grant
    Filed: October 12, 1993
    Date of Patent: February 21, 1995
    Assignee: Intevac, Inc.
    Inventors: Verle W. Aebi, Kenneth A. Costello
  • Patent number: 5374868
    Abstract: A field emitter structure is formed, having trench accessible cold cathode tips is fabricated by forming trenches in a substrate. The trenches are subsequently filled with a conformal insulating layer, a highly conductive layer, and a polysilicon layer. The layers are etched to form emitter tips which are disposed contiguous with the trenches. Electrical signals are propagated through the trenches permitting increased performance of the emitter structure.
    Type: Grant
    Filed: September 11, 1992
    Date of Patent: December 20, 1994
    Assignee: Micron Display Technology, Inc.
    Inventors: Kevin Tjaden, J. Brett Rolfson
  • Patent number: 5367218
    Abstract: The present invention relates to a multiplier structure having a very compact shape and which can have the output electrodes of the channels arranged in any random direction. The multiplying structure (94) is a ceramic block obtained by baking a stack of ceramic sheets prepared beforehand with a view to forming cavities includes in the mass. Each cavity (21) is covered by a metal deposit connected to a lateral contact (23) by a conductor (24) printed beforehand on the corresponding sheet. The channels can have special geometries in order to have their output on several different surfaces (41, 46, 47) of the multiplying structure.
    Type: Grant
    Filed: May 21, 1992
    Date of Patent: November 22, 1994
    Assignee: Commissariat a l'Energie Atomique
    Inventor: Georges Comby
  • Patent number: 5334085
    Abstract: The invention relates to a manufacturing process for an impregnated cathode for an electron tube and the impregnated cathode obtained in this manner. The method consists in mixing (b) a powder (Y) containing the emissive elements (generally barium and calcium aluminates) with powder (W) of at least one refractory metal (generally tungsten, if necessary mixed with a platinum ore metal), then pressing (c) this mixture into a pellet (1) which is then sintered (d) at a high temperature in hydrogen (approx. 2000.degree. C.). In the prior art of this method, a powder of at least one refractory metal was pressed and sintered and then impregnated, machined, cleaned, etc. The process according to the invention therefore saves many steps in the manufacture of an impregnated cathode with respect to the prior art.
    Type: Grant
    Filed: May 26, 1992
    Date of Patent: August 2, 1994
    Assignee: Thomson Tubes Electroniques
    Inventor: Arvind Shroff
  • Patent number: 5314364
    Abstract: To maintain a monolayer of scandium, which is necessary for a satisfactory emission on the surface of a scandate cathode, at least the top layer of the cathode is provided with a scandium-containing oxidic phase from which Scandium is supplied by segregation of scandium from this oxidic phase.
    Type: Grant
    Filed: August 17, 1992
    Date of Patent: May 24, 1994
    Assignee: U.S. Philips Corporation
    Inventors: Frans M. M. Snijkers, Jacobus E. Crombeen
  • Patent number: 5312514
    Abstract: Method of making a field emitter device with submicron low work function emission tips without using photolithography. The method includes depositing in situ by evaporating or sputtering a discontinuous etch mask comprising randomly located discrete nuclei. In one embodiment an ion etch is applied to a low work function material covered by a discontinuous mask to form valleys in the low work function material with pyramid shaped emission tips therebetween. In another embodiment an ion etch is applied to an electrically conductive base material covered by a discontinuous mask to form valleys in the base material with pyramid shaped base tips therebetween. The base material is then coated with a low work function material to form emission tips thereon.
    Type: Grant
    Filed: April 23, 1993
    Date of Patent: May 17, 1994
    Assignee: Microelectronics and Computer Technology Corporation
    Inventor: Nalin Kumar
  • Patent number: 5302238
    Abstract: An in situ plasma dry etching process for the formation of automatically sharp cold cathode emitter tips for use in field emission displays in which i) a mask layer is deposited on a substrate, ii) a photoresist layer is patterned superjacent the mask layer at the sites where the emitter tips are to be formed, iii) the mask is selectively removed by plasma etching, iv) after which the substrate is etched in the same plasma reacting chamber, thereby creating sharp electron emitter tips.
    Type: Grant
    Filed: May 15, 1992
    Date of Patent: April 12, 1994
    Assignee: Micron Technology, Inc.
    Inventors: Fred L. Roe, Kevin Tjaden
  • Patent number: 5277637
    Abstract: A cathode having a short heating time and a long lifetime for an electric discharge tube is provided. The cathode comprises a metal (particularly nickel) support base coated with a layer of potentially electron-emissive material, which support base has a thickness ranging between 20 and 150 .mu.m, while the metal crystallites have a size which does not permit of any further crystallite growth or recrystallization. Particularly, the crystallites of the support base have a size which corresponds to the thickness of the support base. The cathode is obtained by a method in which the recrystallization thermal treatment is effective to prevent additions in the metal of the support base from forming oxides to a depth which is further than 1 micrometer from the surface.
    Type: Grant
    Filed: July 2, 1992
    Date of Patent: January 11, 1994
    Assignee: U.S. Philips Corporation
    Inventor: Petrus J. A. M. Derks
  • Patent number: 5270258
    Abstract: A method of manufacturing a microminiature vacuum tube includes forming a mask layer on a first surface of a monocrystalline substrate and removing the mask layer where a cathode is to be formed, anisotropically etching the monocrystalline substrate at the surface using the mask layer to form a recess in the substrate having a V-shaped cross-section, covering the V-shaped recess with an electron-emitting cathode material, successively forming a first insulator film, a gate material, a second insulator film, and an anode material on the second surface of the substrate, removing portions of the anode material, second insulator film, gate material, and first insulator film from a portion of the second surface opposite the V-shaped recess, and etching the monocrystalline substrate using the first insulator film as a mask until the tip of the cathode material is exposed. Uniformly shaped cathodes can be formed with good controllability and reproducibility according to the invention.
    Type: Grant
    Filed: June 25, 1991
    Date of Patent: December 14, 1993
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Masahiro Yoshida
  • Patent number: 5261845
    Abstract: A cathode body for an impregnated scandate cathode is obtained by compressing and sintering a mixture of tungsten powder with approximately 0.5% by weight of scandium, whereafter the body is impregnated.
    Type: Grant
    Filed: July 30, 1991
    Date of Patent: November 16, 1993
    Assignee: U.S. Philips Corporation
    Inventors: Johannes Van Esdonk, Jan Hasker, Josef Van Lith
  • Patent number: 5256095
    Abstract: An electrode of a discharge lamp which has an improved adhesion between an emitter material and a filament is formed in accordance with the following method. That is, a Fe-Cr-Al alloy is used as the filament. The filament is placed in a heated oxidizing environment to precipitate an aluminum oxide layer uniformly in a surface thereof. Thus precipitated aluminum oxide layer has good adhesion with the filament without flaking thereof. The aluminum oxide layer is coated with triple carbonates consisting of barium carbonate, calcium carbonate and strontium carbonate, so that a carbonate coated filament is obtained. And then, the coated filament is heated in vacuum to reduce the carbonates to their alkaline earth oxides of the emitter material, and also to form a complex oxide consisting of the aluminum oxide and the alkaline earth oxides.
    Type: Grant
    Filed: November 16, 1992
    Date of Patent: October 26, 1993
    Assignee: Matsushita Electric Works, Ltd.
    Inventors: Yoshinobu Takegawa, Shigetoshi Sakon, Shuji Yamada
  • Patent number: 5219310
    Abstract: A method for producing a planar type electron radiating device including a plurality of cathodes having pointed ends on a major surface of a substrate, and a gate electrode having holes in the vicinity of the cathodes, is disclosed. After a hole is formed in the gate electrode and a silicon oxide film for laying a part of the major surface of the substrate to outside, a chromium thin film as a tight metal bonding film is deposited on the bottom of the hole prior to formation of the cathode, and the cathode is formed on the chromium thin film to prevent the cathode from being detached during the production process.
    Type: Grant
    Filed: March 13, 1992
    Date of Patent: June 15, 1993
    Assignee: Sony Corporation
    Inventors: Yoichi Tomo, Hidetoshi Watanabe
  • Patent number: 5211707
    Abstract: A field emission cathode having a parallel array of individual electrically conductive rods of metal silicide or germanide in a silicon-based or germanium-based single crystal matrix. Each rod has an emission end exposed at one major surface of the cathode and an ohmic contact end exposed at an opposite major surface. In a preferred cathode, the matrix and rod materials are the constituents of a eutectic composition. The cathode is fabricated by a process involving producing a composite boule from a eutectic composition of a silicon-based or germanium-based material and a metal. The composite cathode body is cut from the boule so that the rods are generally normal to the major surfaces. Etching may be used to expose a uniform length of the rods at the emitting surface.
    Type: Grant
    Filed: July 11, 1991
    Date of Patent: May 18, 1993
    Assignee: GTE Laboratories Incorporated
    Inventors: Brian M. Ditchek, Mark A. Neifeld, John C. Gustafson
  • Patent number: 5203731
    Abstract: The present invention relates generally to a new integrated Vacuum Microelectronic Device (VMD) and a method for making the same. Vacuum Microelectronic Devices require several unique three dimensional structures: a sharp field emission tip, accurate alignment of the tip inside a control grid structure in a vacuum environment, and an anode to collect electrons emitted by the tip. Also disclosed is a new structure and a process for forming diodes, triodes, tetrodes, pentodes and other similar structures. The final structure made can also be connected to other similar VMD devices or to other electronic devices.
    Type: Grant
    Filed: March 5, 1992
    Date of Patent: April 20, 1993
    Assignee: International Business Machines Corporation
    Inventor: Steven M. Zimmerman
  • Patent number: 5173634
    Abstract: A field emission device is set forth for providing a current-regulating and potential equilibrium function.
    Type: Grant
    Filed: November 30, 1990
    Date of Patent: December 22, 1992
    Assignee: Motorola, Inc.
    Inventor: Robert C. Kane
  • Patent number: 5171180
    Abstract: A method for manufacturing an impregnated cathode wherein an impregnated pallet is fixedly fitted in a cathode cup. The method comprises the step of disposing electron emitting materials together with a porous pallet in the cathode cup and impregnating the electron emitting materials in the porous pallet to produce the impregnated pallet. The cathode cup is constituted by alloying an oxidative metal or alloy, such as silicon (Si), nickel (Ni) or chromium (Cr), which tends to react oxidatively with the electron emitting materials, in a high heat-resistant metal. In the impregnation process, a bonding of the impregnated pallet to the cathode cup can be achieved by an oxidation reaction between the electron emitting matetrials in the impregnated pallet and the oxidative material in the cathode cup, without any expensive brazing metals or alloys. As a result, it is possible to reduce the manufacturing cost and the total manufacturing processes.
    Type: Grant
    Filed: April 21, 1992
    Date of Patent: December 15, 1992
    Assignee: Gold Star Co., Ltd.
    Inventor: Kyung S. Lee
  • Patent number: 5122707
    Abstract: A cathode for use in electron tubes which comprises a base metal made of nickel as a principal component and having a surface on which a porous electron emissive layer is formed. The porous electron emissive layer is of a composition comprising 0.1 to 20 wt % (relative to the total weight of the porous electron emissive layer) of scandium oxide having a layered crystalline structure dispersed in an oxide of alkaline earth metal including at least barium. This cathode can be made by preparing a solution in which nitrocellulose is dissolved with the use of an organic solvent, mixing both of barium carbonate and scandium oxide having a layered crystalline structure into the solution to provide an suspension, pulverizing solid components of the suspension for the adjustment of particle size, and depositing the suspension on a surface of the base metal to form the electron emissive layer.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: June 16, 1992
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Hisao Nakanishi, Kinjiro Sano, Toyokazu Kamata, Keiji Watanabe, Masato Saito, Ryo Suzuki, Keiji Fukuyama, Masako Ishida
  • Patent number: 5121027
    Abstract: This invention relates to an oxide-coated cathode for CRT and a manufacturing method thereof, where Scandium (Sc) or Scandium Oxide (Sc.sub.2 O.sub.3) is vaporized and ionized into a gas state under the oxygen existing environment, and is accelerated onto the surface of a base of Ni containing small amounts of a reducing element such as Mg or Si to form an implantation layer in a certain depth within the base, thereby enhancing the electron emissive characteristics and lengthening the longevity of the cathode.
    Type: Grant
    Filed: August 19, 1991
    Date of Patent: June 9, 1992
    Assignee: Samsung Electron Devices Co., Ltd.
    Inventors: N., Hwan-Chul, Jong-In Jeong, Jong-Seo Choi, Jong-Ho Oh, Kyu-Nam Ju
  • Patent number: 5118317
    Abstract: A storage cathode comprising a porous, sintered body of a refractory metal is produced by compacting and sintering powder particles of a refractory metal, at least a portion of which are coated, before compacting, with a thin layer of a ductile metal. As a result thereof, it is possible to compact the refractory metal powder, before sintering, at temperatures lower than 600.degree. C., in a non-conditioned space and in an air atmosphere.
    Type: Grant
    Filed: October 16, 1991
    Date of Patent: June 2, 1992
    Assignee: U.S. Philips Corporation
    Inventor: Jan F. C. M. Wijnen
  • Patent number: 5114742
    Abstract: An improved scandate cathode having an increased emission density is prepared from a porous tungsten billet that has been impregnated with Ba.sub.3 Al.sub.2 O.sub.6 by coating the top surface of the impregnated billet with a mixture of Sc.sub.6 WO.sub.12,Sc(WO.sub.4).sub.3, and W in the mole ratio of 1:3:2, heating the billet to about 1000.degree. C. in a vacuum to cause BaWO.sub.4 and Sc to form in the billet in a molar ratio of 1:1, removing the billet and cleaning in a jewelers lathe, and preparing the billet for a cathode environment.
    Type: Grant
    Filed: July 17, 1991
    Date of Patent: May 19, 1992
    Assignee: The United States of America as represented by the Secretary of the Army
    Inventors: Louis F. Branovich, Gerard L. Freeman, Donald W. Eckart