Patents by Inventor Masaaki Okunaka
Masaaki Okunaka 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: 8237353Abstract: In a top emission type organic EL display device, brightness gradient in a screen is reduced while keeping a screen brightness. A reflection film is formed under a lower electrode and the light from an organic EL layer is emitted through an upper electrode. Light absorption of the upper electrode is larger on the side of a shorter wavelength. When a film thickness of the upper electrode is enlarged in order to reduce the brightness gradient in a screen, the film thicknesses of the upper electrodes for a red pixel and a green pixel are enlarged without enlarging the film thickness of the upper electrode for a blue pixel. This makes it possible to reduce the brightness gradient as well as to suppress the light absorption of the upper electrode.Type: GrantFiled: July 9, 2009Date of Patent: August 7, 2012Assignees: Hitachi Displays, Ltd., Panasonic Liquid Crystal Display Co., Ltd.Inventors: Hironori Toyoda, Masahiro Tanaka, Masaaki Okunaka, Masakazu Gunji
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Patent number: 8129902Abstract: An organic EL display device includes a substrate, pixel regions, each having a first electrode, a light emitting material layer, and a second electrode, and a bank film formed by a laminated structure of a plurality of inorganic material films having different etching rates from one another formed above the substrate to separate pixel regions from one another. The bank film has openings exposing upper surfaces of the first electrodes to the light emitting material layers, and the second electrode is formed over the openings in common with the pixel regions. A side wall of the bank film around the openings thereof is sloped at an angle 10 to 85 degrees (°) with respect to a principal surface of the substrate to prevent deterioration of the light emitting material layer and disconnection of the second electrode at steps of the bank film in the vicinity of the openings.Type: GrantFiled: December 18, 2009Date of Patent: March 6, 2012Assignees: Hitachi Displays, Ltd., Panasonic Liquid Crystal Display Co., Ltd.Inventors: Kazuhiko Kai, Masaaki Okunaka, Naoyuki Ito
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Patent number: 7786666Abstract: An organic electroluminescent display device with an extended lifetime is provided. When at least a hole transport layer HTR, a light emitting layer LUM, an electron transport layer ETR and an electron injection layer EIN are stacked between one electrode (an anode AND or a cathode CTD) formed on the principal surface of an insulating substrate SUB1 and the other electrode (the cathode CTD or the anode AND) by vapor deposition, the concentration of a plasticizer trapped into the layers in a vapor deposition apparatus is limited to less than or equal to 100 ppm.Type: GrantFiled: September 26, 2006Date of Patent: August 31, 2010Assignee: Hitachi Displays, Ltd.Inventors: Masaaki Okunaka, Masato Ito, Masamitsu Furuie, Hironori Toyoda, Naoyuki Itou
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Publication number: 20100164372Abstract: An organic EL display device includes a substrate, pixel regions, each having a first electrode, a light emitting material layer, and a second electrode, and an organic bank film formed above the substrate to separate pixel regions from one another. The bank film has openings exposing upper surfaces of the first electrodes to the light emitting material layers, and the second electrode is formed over the openings in common with the pixel regions. A side wall of the bank film around the openings thereof is sloped at an angle less than 85 degrees (°) with respect to a principal surface of the substrate to prevent deterioration of the light emitting material layer and disconnection of the second electrode at steps of the bank film in the vicinity of the openings.Type: ApplicationFiled: December 18, 2009Publication date: July 1, 2010Inventors: Kazuhiko KAI, Masaaki Okunaka, Naoyuki Ito
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Patent number: 7705531Abstract: In an organic electroluminescent display device having light emitting layers which are independently controlled and emit light formed in respective pixel regions on a principal surface of a substrate and emitting light from each of the light emitting layer through the substrate, the present invention arranges a light shielding member on an end wall face of the substrate and prevents the light from leaking from the end wall face thereof.Type: GrantFiled: July 23, 2004Date of Patent: April 27, 2010Assignee: Hitachi Displays, Ltd.Inventors: Masamitsu Furuie, Shinichi Kato, Masaaki Okunaka, Masato Ito, Hirotsugu Sakamoto
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Patent number: 7671825Abstract: According to one aspect of the present invention, it is possible to sufficiently perform the discharging of charge without lowering the light emitting efficiency of an organic EL device and hence, the device can exhibit the light emitting efficiency higher than a conventional organic EL device and, at the same time, can prevent the degradation of the device. As an organic EL device to which the present invention is applied, on a glass transparent substrate, a transparent electrode, a hole injection layer and a hole transport layer which function as a hole transport function layer, a light emitting layer, an electron transport function layer, and a metal electrode are formed sequentially, and a drive power sources are connected to the transparent electrode and the metal electrode.Type: GrantFiled: February 24, 2006Date of Patent: March 2, 2010Assignee: Hitachi Displays, Ltd.Inventors: Norikazu Uchiyama, Masaaki Okunaka, Masahiro Nishizawa, Hidetsugu Matsukiyo, Yuko Matsumoto
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Publication number: 20100007272Abstract: In a top emission type organic EL display device, brightness gradient in a screen is reduced while keeping a screen brightness. A reflection film is formed under a lower electrode and the light from an organic EL layer is emitted through an upper electrode. Light absorption of the upper electrode is larger on the side of a shorter wavelength. When a film thickness of the upper electrode is enlarged in order to reduce the brightness gradient in a screen, the film thicknesses of the upper electrodes for a red pixel and a green pixel are enlarged without enlarging the film thickness of the upper electrode for a blue pixel. This makes it possible to reduce the brightness gradient as well as to suppress the light absorption of the upper electrode.Type: ApplicationFiled: July 9, 2009Publication date: January 14, 2010Inventors: Hironori Toyoda, Masahiro Tanaka, Masaaki Okunaka, Masakazu Gunji
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Patent number: 7642701Abstract: In an organic EL display device comprising a substrate, a plurality of pixel regions in each of which a first electrode, a light emitting material layer, and a second electrode are laminated in this order above the substrate, and a bank film formed above the substrate to separate respective one of the pixel regions from another of the pixel regions adjacent thereto, wherein the bank film has a plurality of openings exposing upper surfaces of the first electrodes to the light emitting material layers in the respective pixel regions, and the second electrode is formed over the a plurality of openings of the bank film in common with the pixel regions, the present invention forms the bank film of an inorganic material and shapes a side wall thereof lying around each of the openings thereof to be sloped at an angle less than 85 degrees (°) with respect to a principal surface of the substrate in order to prevent the deterioration of the light emitting material layer and disconnection of the second electrode at stepType: GrantFiled: October 11, 2007Date of Patent: January 5, 2010Assignee: Hitachi Displays, Ltd.Inventors: Kazuhiko Kai, Masaaki Okunaka, Naoyuki Ito
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Publication number: 20090051285Abstract: An object of the present invention is to provide an organic electroluminescence (EL) display device having a high aperture ratio (ratio of light emitting area to pixel area) on both surfaces. The organic EL display device having a substrate includes on a surface of the substrate: a first organic EL element of a top emission type; a second organic EL element of a bottom emission type; a first circuit that drives the first organic EL element; and a second circuit that drives the second organic EL element. In the organic EL display device, the second circuit is arranged below the first organic EL element.Type: ApplicationFiled: August 22, 2008Publication date: February 26, 2009Inventors: Kenta Kajiyama, Masaaki Okunaka
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Patent number: 7479953Abstract: The present invention provides a display device which can obviate the possibility of sticking as a whole of a display area even when the brightness is relatively changed on a display area. In a display device, a plurality of pixels are arranged in the inside of a display area and the respective pixels include electrodes to which signals are independently inputted and a common second electrode to which a reference signal with respect to the signals is inputted, the current from the cathode electrode in the first and second display areas are respectively measured, and when the electric current of the first display area is larger than the electric current of the second display area, a potential difference between the cathode electrode of the first display area and the anode electrode of the first display area is made small.Type: GrantFiled: August 19, 2005Date of Patent: January 20, 2009Assignee: Hitachi Displays, Ltd.Inventors: Hironori Toyoda, Shinichi Kato, Masamitsu Furuie, Masaaki Okunaka, Naoki Tokuda
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Patent number: 7474046Abstract: The present invention provides a display device which can suppress mura or irregularities of brightness of a display. To be more specific, in a display device including the plurality of pixels which are arranged in a matrix array and are respectively provided with light emitting layers, a power source is supplied to the respective light emitting layers of the respective pixels which are arranged in parallel in one direction among the respective pixels through a common power source signal line, wherein the respective pixels allow the light emitting layers thereof to have different thicknesses from each other in a state that the thickness of the light emitting layer at an upstream side of a flow of an electric current along the power source signal line is larger than the thickness of the light emitting layer at a downstream side of the flow of the electric current along the power source signal line.Type: GrantFiled: November 28, 2005Date of Patent: January 6, 2009Assignee: Hitachi Displays, Ltd.Inventors: Masamitsu Furuie, Hironori Toyoda, Masaaki Okunaka
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Publication number: 20080290789Abstract: In an organic EL display device comprising a substrate, a plurality of pixel regions in each of which a first electrode, a light emitting material layer, and a second electrode are laminated in this order above the substrate, and a bank film formed above the substrate to separate respective one of the pixel regions from another of the pixel regions adjacent thereto, wherein the bank film has a plurality of openings exposing upper surfaces of the first electrodes to the light emitting material layers in the respective pixel regions, and the second electrode is formed over the a plurality of openings of the bank film in common with the pixel regions, the present invention forms the bank film of an inorganic material and shapes a side wall thereof lying around each of the openings thereof to be sloped at an angle less than 85 degrees (°) with respect to a principal surface of the substrate in order to prevent the deterioration of the light emitting material layer and disconnection of the second electrode at stepType: ApplicationFiled: October 11, 2007Publication date: November 27, 2008Inventors: Kazuhiko KAI, Masaaki Okunaka, Naoyuki Ito
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Patent number: 7332854Abstract: In an organic EL display device comprising a substrate, a plurality of pixel regions in each of which a first electrode, a light emitting material layer, and a second electrode are laminated in this order above the substrate, and a bank film formed above the substrate to separate respective one of the pixel regions from another of the pixel regions adjacent thereto, wherein the bank film has a plurality of openings exposing upper surfaces of the first electrodes to the light emitting material layers in the respective pixel regions, and the second electrode is formed over the a plurality of openings of the bank film in common with the pixel regions, the present invention forms the bank film of an inorganic material and shapes a side wall thereof lying around each of the openings thereof to be sloped at an angle less than 85 degrees (°) with respect to a principal surface of the substrate in order to prevent the deterioration of the light emitting material layer and disconnection of the second electrode at stepType: GrantFiled: March 20, 2006Date of Patent: February 19, 2008Assignee: Hitachi Displays, Ltd.Inventors: Kazuhiko Kai, Masaaki Okunaka, Naoyuki Ito
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Publication number: 20070236425Abstract: In an organic light emitting display device, a plurality of pixel regions are formed two-dimensionally on a transparent substrate, wherein each pixel region includes the multilayered structure which is formed by sequentially stacking a lower transparent electrode, an organic light emitting layer (including at least one organic material layer) and an upper reflection electrode from the transparent substrate side. In such a constitution, at least one concavity which forms a recessed surface with respect to the transparent substrate is formed in the multilayered structure of each pixel region, thus enlarging the effective area of a light emitting portion so as to provide an image display of high brightness with a low current. The concavities are, for example, formed by a plurality of projecting portions on the transparent substrates and by covering the projecting portions with the multilayered structure.Type: ApplicationFiled: January 30, 2004Publication date: October 11, 2007Inventors: Masamitus Furuie, Shinichi Kato, Masaaki Okunaka, Hiroshi Oooka, Naoyuki Ito
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Publication number: 20070216290Abstract: An organic EL light emitting display device is provided which includes a matrix array having a plurality of pixel circuits, each including an organic light emitting element. A scan driving circuit and a current supply circuit are coupled to the pixel circuits. In addition, a plurality of pads are provided which are adapted to connect the scan driving circuit and the current supply circuit to external circuits. In accordance with one embodiment, the pads are located to be closer to the current supply circuit than to the scan driving circuit.Type: ApplicationFiled: May 15, 2007Publication date: September 20, 2007Inventors: Genshiro Kawachi, Toshihiro Sato, Masaaki Okunaka, Noaki Tokuda
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Patent number: 7258586Abstract: When any of pixels is not lit in an organic EL display having an organic EL layer between a first electrode and a second electrode, an organic layer of the pixel is observed. If the organic layer of the pixel contains foreign matter, the second electrode is separated into a region in contact with the foreign matter and a region not in contact with both the contact region and the foreign matter. Thus, not-lit display regions are reduced as less as possible, making it possible to manufacture an organic EL display excellent in display performance.Type: GrantFiled: June 29, 2004Date of Patent: August 21, 2007Assignee: Hitachi Displays, Ltd.Inventors: Takuo Tamura, Mikio Hongo, Masaaki Okunaka, Shinichi Kato, Eiji Matsuzaki, Masato Ito, Masatomo Terakado
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Publication number: 20070069640Abstract: An organic electroluminescent display device with an extended lifetime is provided. When at least a hole transport layer HTR, a light emitting layer LUM, an electron transport layer ETR and an electron injection layer EIN are stacked between one electrode (an anode AND or a cathode CTD) formed on the principal surface of an insulating substrate SUB1 and the other electrode (the cathode CTD or the anode AND) by vapor deposition, the concentration of a plasticizer trapped into the layers in a vapor deposition apparatus is limited to less than or equal to 100 ppm.Type: ApplicationFiled: September 26, 2006Publication date: March 29, 2007Inventors: Masaaki Okunaka, Masato Ito, Masamitsu Furuie, Hironori Toyoda, Naoyuki Itou
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Publication number: 20060197462Abstract: According to one aspect of the present invention, it is possible to sufficiently perform the discharging of charge without lowering the light emitting efficiency of an organic EL device and hence, the device can exhibit the light emitting efficiency higher than a conventional organic EL device and, at the same time, can prevent the degradation of the device. As an organic EL device to which the present invention is applied, on a glass transparent substrate, a transparent electrode, a hole injection layer and a hole transport layer which function as a hole transport function layer, a light emitting layer, an electron transport function layer, and a metal electrode are formed sequentially, and a drive power sources are connected to the transparent electrode and the metal electrode.Type: ApplicationFiled: February 24, 2006Publication date: September 7, 2006Inventors: Norikazu Uchiyama, Masaaki Okunaka, Masahiro Nishizawa, Hidetsugu Matsukiyo, Yuko Matsumoto
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Publication number: 20060158107Abstract: In an organic EL display device comprising a substrate, a plurality of pixel regions in each of which a first electrode, a light emitting material layer, and a second electrode are laminated in this order above the substrate, and a bank film formed above the substrate to separate respective one of the pixel regions from another of the pixel regions adjacent thereto, wherein the bank film has a plurality of openings exposing upper surfaces of the first electrodes to the light emitting material layers in the respective pixel regions, and the second electrode is formed over the a plurality of openings of the bank film in common with the pixel regions, the present invention forms the bank film of an inorganic material and shapes a side wall thereof lying around each of the openings thereof to be sloped at an angle less than 85 degrees (°) with respect to a principal surface of the substrate in order to prevent the deterioration of the light emitting material layer and disconnection of the second electrode at stepType: ApplicationFiled: March 20, 2006Publication date: July 20, 2006Inventors: Kazuhiko Kai, Masaaki Okunaka, Naoyuki Ito
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Publication number: 20060114176Abstract: The present invention provides a display device which can suppress mura or irregularities of brightness of a display. To be more specific, in a display device including the plurality of pixels which are arranged in a matrix array and are respectively provided with light emitting layers, a power source is supplied to the respective light emitting layers of the respective pixels which are arranged in parallel in one direction among the respective pixels through a common power source signal line, wherein the respective pixels allow the light emitting layers thereof to have different thicknesses from each other in a state that the thickness of the light emitting layer at an upstream side of a flow of an electric current along the power source signal line is larger than the thickness of the light emitting layer at a downstream side of the flow of the electric current along the power source signal line.Type: ApplicationFiled: November 28, 2005Publication date: June 1, 2006Inventors: Masamitsu Furuie, Hironori Toyoda, Masaaki Okunaka