Patents by Inventor Iwao Ohwada
Iwao Ohwada has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7651655Abstract: A method of producing a dielectric layer made of a polycrystalline dielectric material having anisotropy in the coefficient of thermal expansion is provided, including the steps of providing a raw material powder, and heat treating the raw material powder at least to a temperature sufficient to cause a phase change from a first crystal orientation at room temperature to a different crystal orientation to provide an aggregate of oriented raw material particles having the same chemical composition as the raw material powder but having the different crystal orientation. The method also includes a step of forming a compact from the aggregate of oriented raw material particles, including a step of applying a shearing force to the aggregate and firing the compact to form the dielectric layer.Type: GrantFiled: December 13, 2005Date of Patent: January 26, 2010Assignee: NGK Insulators, Ltd.Inventors: Takaaki Koizumi, Hirofumi Yamaguchi, Iwao Ohwada, Tsutomu Nanataki
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Patent number: 7635944Abstract: An electron-emitting device includes an emitter section composed of a dielectric material, a lower electrode disposed on the lower side of the emitter section, and an upper electrode disposed on the upper side of the emitter section so as to be opposed to the lower electrode with the emitter section therebetween, electrons being emitted from the emitter section through the upper electrode by the application of a drive voltage between the lower electrode and the upper electrode, wherein the upper electrode is provided with a plurality of through-holes which expose the emitter section and which have an average diameter of 10 nm or more and less than 100 nm, and a peripheral portion of each through-hole facing the emitter section is separated at a predetermined distance from the emitter section.Type: GrantFiled: November 29, 2005Date of Patent: December 22, 2009Assignee: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Masao Takahashi, Takayoshi Akao, Shuichi Ozawa, Kei Kosaka
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Patent number: 7528539Abstract: An electron emitter includes an emitter layer formed of a dielectric material, an upper electrode, and a lower electrode. A drive voltage is applied between the upper electrode and the lower electrode, for emitting electrons. The upper electrode is formed of scale-like conductive particles on the upper surface of the emitter layer and has a plurality of opening portions. The surfaces of overhanging portions of the opening portions that face the emitter layer are apart from the emitter layer. The overhanging portions each have such a cross-sectional shape as to be acutely pointed toward the inner edge of the opening portion, or the tip end of the overhanging portion, so that lines of electric force concentrate at the inner edge.Type: GrantFiled: June 2, 2005Date of Patent: May 5, 2009Assignee: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Kei Sato, Nobuyuki Kobayashi, Shohei Yokoyama
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Patent number: 7518131Abstract: An electron beam irradiating apparatus includes a chamber being kept under vacuum, and housing a planar electron emitting element and a positioning unit and an object to be irradiated is directly irradiated with an electron beam emitted from the element. The planar electron emitting element includes: an emitter portion composed of a dielectric material; and a first electrode and a second electrode applied with a driving voltage for emitting electrons, and the first electrode is formed on a first surface of the emitter portion and has a plurality of through-holes where the emitter portion is exposed, a surface of the first electrode facing to the emitter portion around the through-holes is separated from the emitter portion, and the electron beam is emitted from the first surface of the emitter portion through the through-holes.Type: GrantFiled: March 21, 2006Date of Patent: April 14, 2009Assignee: NGK Insulators, Ltd.Inventors: Tsutomu Nanataki, Iwao Ohwada, Yuki Bessho, Takayoshi Akao
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Patent number: 7474060Abstract: A light source has a light emission section comprising a two-dimensional array of electron emitters and a drive circuit for applying a drive voltage to each of the electron emitters of the light emission section. The drive circuit applies the drive voltage between upper and lower electrodes of each of the electron emitters based on a control signal representative of turn-on/turn-off from an external source (a turn-on/turn-off switch or the like), for thereby controlling each of the electron emitters. Each of the electron emitters has a plate-like emitter, an upper electrode disposed on a face side of the emitter, and a lower electrode disposed on a reverse side of the emitter.Type: GrantFiled: August 16, 2004Date of Patent: January 6, 2009Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada, Takayoshi Akao
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Patent number: 7379037Abstract: One image is displayed in a period as one frame, which includes one charge accumulation period and one light emission period. In the charge accumulation period, all electron emitters are scanned, and voltages depending on the luminance levels of corresponding pixels are applied to the electron emitters which correspond to pixels to be turned on (to emit light), to accumulate charges (electrons) in amounts depending on the luminance levels of corresponding pixels in the electron emitters which correspond to pixels to be turned on. In the next light emission period, a constant voltage is applied to all the electron emitters to emit electrons in amounts depending on the luminance levels of corresponding pixels from the electron emitters which correspond to pixels to be turned on, thereby emitting light from the pixels to be turned on.Type: GrantFiled: March 24, 2004Date of Patent: May 27, 2008Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada, Takayoshi Akao
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Patent number: 7336026Abstract: An electron emitter has an emitter made of a dielectric material and an upper electrode and a lower electrode for being supplied with a drive voltage for emitting electrons. The upper electrode is disposed on an upper surface of the emitter, and the lower electrode is disposed on a lower surface of the emitter. The upper electrode has a plurality of through regions through which the emitter is exposed. Each of the through regions of the upper electrode has a peripheral portion having a surface facing the emitter and spaced from the emitter.Type: GrantFiled: September 27, 2004Date of Patent: February 26, 2008Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada, Takayoshi Akao
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Patent number: 7307383Abstract: An electron emitter includes an emitter section having a plate shape, a cathode electrode formed on a front surface of the emitter section, and an anode electrode formed on a back surface of the emitter section. A gap is formed between an outer peripheral portion of the cathode electrode and the front surface of the emitter section. The front surface of the emitter section contacts a lower surface of the outer peripheral portion to form a base end as a triple junction. The gap expands from the base end toward a tip end of the outer peripheral portion.Type: GrantFiled: September 28, 2004Date of Patent: December 11, 2007Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada
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Patent number: 7304440Abstract: An electron emitting apparatus includes a lower electrode, an emitter section made of a dielectric material, a plurality of upper electrodes having micro through holes, and a collector electrode opposing the upper electrodes. In this electron-emitting apparatus, electrons are accumulated in the emitter section by controlling the potential difference (drive voltage) between the lower and upper electrodes with respect to the potential of the lower electrode to a negative predetermined voltage. At this time, the collector electrode of the electron-emitting apparatus is grounded. Thus, unnecessary electron-emitting is suppressed. Subsequently, the drive voltage is changed to a positive predetermined voltage. As a result, polarization reversal occurs in the emitter section, and accumulated electros are emitted through the micro through holes in the upper electrodes by Coulomb repulsion. At this time, a positive voltage Vc is applied to the collector electrode to give large energy to accelerate the electrons.Type: GrantFiled: September 27, 2005Date of Patent: December 4, 2007Assignee: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Takayoshi Akao, Tetsuyuki Kameji, Hirokazu Nakamura
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Patent number: 7288881Abstract: Primary electrons impinge upon an emitter section of an electron emitter for causing emission of the secondary electrons. The secondary electrons are outputted from the electron emitter. The secondary electrons emitted from the emitter section are accelerated in an electric field applied to the emitter section for generating an electron beam. The electron emitter has the emitter section having a plate shape, a cathode electrode formed on a front surface of the emitter section, an anode electrode formed on a back surface of the emitter section. A drive voltage from a pulse generation source is applied between the cathode electrode and the anode electrode through a resistor. The anode electrode is connected to GND. A collector electrode is provided above the cathode electrode. A bias voltage is applied to the collector electrode.Type: GrantFiled: November 21, 2003Date of Patent: October 30, 2007Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada
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Publication number: 20070222393Abstract: The electron emitting device 10 includes a substrate 11, a lower electrode 12, an emitter section 13, an upper electrode 14. The upper electrode disposed above the emitter section to oppose the lower electrode so as to sandwich the emitter section with the lower electrode. The upper electrode has a plurality of micro through holes. The upper electrode is configured in such a manner that distance t1 (gap distance t1) between the lower surface of the upper electrode in the vicinity of the micro through holes 14c and the upper surface of the emitter section is substantially constant for any of the micro through holes.Type: ApplicationFiled: September 29, 2006Publication date: September 27, 2007Applicant: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Takayoshi Akao
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Publication number: 20070188418Abstract: An electron-emitting apparatus includes an electron-emitting element having a lower electrode, a dielectric emitter section, upper electrodes having micro through holes, and a circuit for applying a drive voltage Vin between the lower and upper electrodes. The drive voltage is applied between the lower and upper electrodes to set an element voltage Vka, which is a potential of the upper electrode relative to a potential of the lower electrode, at a negative voltage for a charge accumulation period Td to accumulate electrons in the emitter section, and to set the element voltage Vka at a predetermined positive voltage for an electron emission period Th to emit electrons from the emitter section. The drive voltage applying circuit stepwise increases the positive voltage during the electron emission period Th and separately emits the electrons accumulated in the emitter section a plurality of times.Type: ApplicationFiled: October 14, 2005Publication date: August 16, 2007Applicant: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Takayoshi Akao, Naoki Goto, Tomohiko Sugiyama
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Patent number: 7230371Abstract: A light source has a rear glass substrate and a front glass substrate having a plate surface disposed in facing relation to a principal surface of the rear glass substrate. The plate surface of the front glass substrate is coated with a phosphor. A two-dimensional array of electron emitters is disposed on the principal surface of the rear glass substrate. A space defined between the rear glass substrate and the front glass substrate is filled with a gas. The gas may be an Hg (mercury) gas or an Xe (xenon) gas.Type: GrantFiled: March 17, 2005Date of Patent: June 12, 2007Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada, Takayoshi Akao
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Publication number: 20070090729Abstract: A piezoelectric/electrostrictive film is formed on a solid-phase support, the piezoelectric/electrostrictive film including an incompletely bonded region which is incompletely bonded in a predetermined pattern to the solid-phase support, and a bonded region which is bonded to the surface of the solid-phase support so that the incompletely bonded region can be separated. The piezoelectric/electrostrictive film is bonded to a substrate and is separated from the solid-phase support in the bonded region. As a result, the incompletely bonded region is transferred to the substrate. The transferred incompletely bonded region is used as a piezoelectric/electrostrictive film for manufacturing a piezoelectric/electrostrictive film device.Type: ApplicationFiled: October 24, 2006Publication date: April 26, 2007Applicant: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Nobuyuki Kobayashi
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Publication number: 20070069622Abstract: An electron emitter includes an emitter layer composed of a dielectric material, a first electrode disposed onto a first surface of the emitter layer, and a second electrode disposed onto the first surface, inside, or onto a second surface opposite to the first surface of the emitter layer. A microscopic recess is disposed on a surface of the first electrode. Alternatively, an opening is disposed in the first electrode, the opening exposing the first surface of the emitter layer to the outside of the electron emitter, and a plurality of microscopic protrusions are disposed along the thickness direction of the first electrode at an inner edge of the opening.Type: ApplicationFiled: February 22, 2006Publication date: March 29, 2007Applicant: NGK Insulators, Ltd.Inventors: Iwao Ohwada, Shuichi Ozawa, Koichi Yoshino, Shohei Yokoyama
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Publication number: 20070063963Abstract: A backlight used for a liquid crystal display including a plurality of liquid crystal display elements arranged in a matrix of n rows and m columns, in which constant-time row scanning is performed in row order to change the optical transmittance of the liquid crystal display elements includes a plurality of electron-emitting elements and a phosphor. Each of the electron-emitting elements is disposed so as to face a liquid crystal display element group including a plurality of adjacent liquid crystal display elements with the phosphor therebetween. An electron emission voltage is applied to electron-emitting elements facing liquid crystal display elements for which the row scanning is completed and whose optical transmittance becomes constant. The electron-emitting elements apply electrons to the phosphor. The phosphor is irradiated with electrons, and emits light to the liquid crystal display elements whose optical transmittance becomes constant.Type: ApplicationFiled: March 22, 2006Publication date: March 22, 2007Applicant: NGK Insulators, Ltd.Inventors: Tsutomu Nanataki, Iwao Ohwada
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Publication number: 20070063962Abstract: A backlight for a liquid crystal display including a plurality of liquid crystal display elements arranged in a matrix of n rows and m columns, in which optical transmittance of each of the liquid crystal display elements is changed, thereby switching an image every one frame period includes a plurality of electron-emitting elements and a phosphor. Each electron-emitting element is disposed to face a liquid crystal display element group including a plurality of adjacent liquid crystal display elements with the phosphor therebetween. In a sub-frame period divided from one frame period, each electron-emitting element accumulates and emits an amount of electrons according to the optical transmittance of each of the plurality of liquid crystal display elements facing each of the electron-emitting elements. In one frame period, the phosphor emits an amount of light which corresponds to the optical transmittance of the liquid crystal display elements a plurality of times.Type: ApplicationFiled: March 22, 2006Publication date: March 22, 2007Applicant: NGK Insulators, Ltd.Inventors: Tsutomu Nanataki, Iwao Ohwada
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Patent number: 7187114Abstract: An electron emitter has an emitter section formed on a substrate, and a cathode electrode and an anode electrode formed on a same surface of the emitter section. A slit is formed between the cathode electrode and the anode electrode. A drive voltage from a pulse generation source is applied between the anode electrode and the cathode electrode. The anode electrode is connected to the ground. A charging film is formed on a surface of the anode electrode.Type: GrantFiled: June 11, 2003Date of Patent: March 6, 2007Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada
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Publication number: 20070040130Abstract: An electron beam irradiating apparatus includes a chamber being kept under vacuum, and housing a planar electron emitting element and a positioning unit and an object to be irradiated is directly irradiated with an electron beam emitted from the element. The planar electron emitting element includes: an emitter portion composed of a dielectric material; and a first electrode and a second electrode applied with a driving voltage for emitting electrons, and the first electrode is formed on a first surface of the emitter portion and has a plurality of through-holes where the emitter portion is exposed, a surface of the first electrode facing to the emitter portion around the through-holes is separated from the emitter portion, and the electron beam is emitted from the first surface of the emitter portion through the through-holes.Type: ApplicationFiled: March 21, 2006Publication date: February 22, 2007Applicant: NGK Insulators, Ltd.Inventors: Tsutomu Nanataki, Iwao Ohwada, Yuki Bessho, Takayoshi Akao
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Patent number: RE40489Abstract: One selection period S and display cycles Td of a number corresponding to a maximum gradation level are allotted in one field, and the display cycle Td is composed of an unselection period U and a reset period R to perform the following control. A row electrode-driving circuit is used to output a selection pulse Ps during the selection period S, output an unselection signal Su during the unselection period U in the display cycle Td, and output a reset pulse Pr during the reset period R. A column electrode-driving circuit is used to output an ON signal during a light emission maintenance period, and output an OFF signal at least at an end timing of the light emission maintenance period, of the period other than the light emission maintenance period. Accordingly, it is possible to effectively reduce the electric power consumption, and it is possible to achieve the high brightness.Type: GrantFiled: November 17, 2004Date of Patent: September 9, 2008Assignee: NGK Insulators, Ltd.Inventors: Yukihisa Takeuchi, Tsutomu Nanataki, Iwao Ohwada, Takayoshi Akao