Patents by Inventor Yoshitaka Takezawa

Yoshitaka Takezawa 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).

  • Publication number: 20120315487
    Abstract: A composite particle is constituted to include: an aluminum nitride particle; a first coating layer that contains ?-alumina and coats at least a part of a region of a surface of the aluminum nitride particle; and a second coating layer that contains organic matter and coats a region other than the first coating layer of the surface of the aluminum nitride particle.
    Type: Application
    Filed: February 17, 2011
    Publication date: December 13, 2012
    Inventors: Yoshitaka Takezawa, Fusao Hojo, Shingo Tanaka, Hiroyuki Kagawa
  • Publication number: 20120251830
    Abstract: A resin composition constituted by containing an epoxy resin monomer having a mesogenic structure, a novolac resin containing a compound having a structural unit represented by the following general formula (I), and an inorganic filler is superior in preservation stability before curing, and can attain high thermal conductivity after curing. In the following general formula (I), R1, R2 and R3 independently represent a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group; m represents an integer of 0 to 2; and n an integer of 1 to 7.
    Type: Application
    Filed: September 28, 2010
    Publication date: October 4, 2012
    Applicant: Hitachi Chemical Company, LTD
    Inventors: Tomoo Nishiyama, Haruaki Sue, Hideyuki Katagi, Naoki Hara, Hiroyuki Takahashi, Yasuo Miyazaki, Yoshitaka Takezawa, Hiroyuki Tanaka, Kensuke Yoshihara, Masayoshi Joumen
  • Publication number: 20120244351
    Abstract: A multilayer resin sheet is constituted by including a resin layer containing an epoxy resin having a mesogenic skeleton, a curing agent and an inorganic filler, and an insulating adhesive layer formed on at least either of the surfaces of the resin layer. A cured multilayer resin sheet originated from the multilayer resin sheet has high thermal conductivity, good insulation and adhesive strength, and, further, superior thermal shock resistance, and is suitable as an electric insulating material to be used for an electric or electronic device.
    Type: Application
    Filed: September 28, 2010
    Publication date: September 27, 2012
    Inventors: Hideyuki Katagi, Yoshitaka Takezawa, Tomoo Nishiyama, Naoki Hara, Hiroyuki Tanaka, Kensuke Yoshihara, Masayoshi Joumen, Hiroyuki Takahashi
  • Patent number: 7989267
    Abstract: Improvement in the reliability of a semiconductor device is aimed at. By heating a lead frame, after preparing a lead frame with a tape, until a resin molding is performed, at the temperature 160 to 300° C. (preferably 180 to 300° C.) for a total of more than 2 minutes in the atmosphere which has oxygen, crosslinkage density becoming high in resin of adhesives, a low molecular compound volatilizes and jumps out outside, therefore as a result, since a low molecular compound does not remain in resin of adhesives, the generation of copper migration can be prevented.
    Type: Grant
    Filed: April 16, 2008
    Date of Patent: August 2, 2011
    Assignee: Renesas Electronics Corporation
    Inventors: Fujio Ito, Hiromichi Suzuki, Akihiko Kameoka, Junpei Kusukawa, Yoshitaka Takezawa
  • Patent number: 7816786
    Abstract: A semiconductor device includes a semiconductor chip and leads electrically connected to the electrodes of the semiconductor chip. A hollow radiator base houses the semiconductor device which is molded with high-thermal-conductivity resin having an electrical insulating property. The radiator base has a cooling-medium channel therein or radiating fins on the outside. Alternatively, the radiator base is housed in a second radiator base.
    Type: Grant
    Filed: February 20, 2009
    Date of Patent: October 19, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Kinya Nakatsu, Hideki Miyazaki, Yoshitaka Takezawa, Toshiaki Ishii, Hiroshi Hozoji
  • Publication number: 20100160555
    Abstract: A resin composition comprising an epoxy compound denoted by the formula (1): wherein Ar1, Ar2 and Ar3 are the same or different and each denotes any one of divalent groups denoted by the following formulas: wherein R denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and an epoxy compound denoted by the formula (2): wherein R5 denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and Q2 denotes a single bond or a straight-chain alkylene group having 1 to 8 carbon atoms.
    Type: Application
    Filed: March 25, 2008
    Publication date: June 24, 2010
    Inventors: Shinya Tanaka, Yoshitaka Takezawa
  • Publication number: 20100144926
    Abstract: A resin composition comprising an epoxy compound denoted by the formula (1): wherein R1, R2, R3, R4 and R5 denote a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, m and n denote an integer of 0 to 4, Ar denotes any one of divalent groups denoted by the following formulas: wherein R denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and an epoxy compound denoted by the formula (2): wherein Q denotes a straight-chain alkylene group having 1 to 8 carbon atoms, methylene groups composing said straight-chain alkylene group are optionally substituted with an alkyl group having 1 to 8 carbon atoms and —O— or —N(R6)— is optionally inserted between the methylene groups, wherein R6 denotes a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
    Type: Application
    Filed: March 25, 2008
    Publication date: June 10, 2010
    Inventors: Shinya Tanaka, Yoshitaka Takezawa
  • Patent number: 7691473
    Abstract: The present invention relates to a fiber-reinforced composite material and a method for manufacturing the same, and also relates to a transparent multilayered sheet, a circuit board, and an optical waveguide.
    Type: Grant
    Filed: October 14, 2008
    Date of Patent: April 6, 2010
    Assignees: Rohm Co., Ltd., Mitsubishi Chemical Corporation, Hitachi, Ltd., Pioneer Corporation
    Inventors: Hiroyuki Yano, Junji Sugiyama, Masaya Nogi, Shin-ichiro Iwamoto, Keishin Handa, Akira Nagai, Takao Miwa, Yoshitaka Takezawa, Toshiyuki Miyadera, Takashi Kurihara, Tohru Matsuura, Nobutatsu Koshoubu, Tohru Maruno
  • Publication number: 20100063182
    Abstract: There is disclosed an epoxy composition containing at least two kinds of epoxy compounds selected from the epoxy compounds of the formula (1): wherein each of Ar1, Ar2 and Ar3, the same as or different from one another, is a bivalent group of any one of the following formulas : wherein R is a hydrogen atom or a C1-8 alkyl group; a is an integer of 1 to 8; each of b, e and g is an integer of 1 to 6; c is an integer of 1 to 7; each of d and h is an integer of 1 to 4; and f is an integer of 1 to 5, wherein, when there are present a plurality of Rs in said bivalent group, Rs may be all the same groups or may be different groups from one another; Q is a C1-8 linear alkylene group, wherein a methylene group constituting the linear alkylene group may be substituted with a C1-8 alkyl group, and wherein a methylene group, not adjacent to an oxygen atom, may be replaced by —O—, and —O— or —N(R4)—may be inserted between methylene groups; each of R1, R2, R3 and R4, the same as or different from one another, is a
    Type: Application
    Filed: April 18, 2008
    Publication date: March 11, 2010
    Inventors: Shinya Tanaka, Yoshitaka Takezawa
  • Publication number: 20090298976
    Abstract: An object of the present invention is to provide a fiber-reinforced composite resin composition for use as a sealant, adhesive, or filler, having a high transparency, and enabled to adequately meet recently required levels of low thermal expansion property, high strength, light weight, high thermal conductivity, and especially high, isotropic thermal conductivity. With the fiber-reinforced composite resin composition, the fibers have an average fiber diameter of 4 to 200 nm, a total light transmittance at wavelengths of 400 to 700 nm as measured with a 50 ?m-thickness cured product, resulting from curing the composition to a plate-like form, is no less than 70%, both a thermal conductivity coefficient in a thickness direction and a thermal conductivity coefficient in a plate surface direction of the cured product are no less than 0.4 W/m·K, and the fibers are oriented randomly in the composition.
    Type: Application
    Filed: October 26, 2006
    Publication date: December 3, 2009
    Inventors: Hiroyuki Yano, Masaya Nogi, Shinsuke Ifuku, Kentaro Abe, Yoshitaka Takezawa, Keishin Handa
  • Publication number: 20090160048
    Abstract: A semiconductor device includes a semiconductor chip and leads electrically connected to the electrodes of the semiconductor chip. A hollow radiator base houses the semiconductor device which is molded with high-thermal-conductivity resin having an electrical insulating property. The radiator base has a cooling-medium channel therein or radiating fins on the outside. Alternatively, the radiator base is housed in a second radiator base.
    Type: Application
    Filed: February 20, 2009
    Publication date: June 25, 2009
    Applicant: Hitachi, Ltd.
    Inventors: Kinya NAKATSU, Hideki MIYAZAKI, Yoshitaka TAKEZAWA, Toshiaki ISHII, Hiroshi HOZOJI
  • Patent number: 7538166
    Abstract: Novel epoxy compounds represented by the general formula (1) wherein Ar1, Ar2 and Ar3 are each optionally substituted phenylene, cyclohexanyl or the like, R1, R2, R3, R4, R5 and R6 are each hydrogen or alkyl of 1 to 18 carbon atoms, and Q1 and Q2 are each alkylene of 1 to 9 carbon atoms or the like, which are useful as the raw material of cured epoxy resins exhibiting liquid crystallinity; a process for the production thereof; and compositions containing the compounds.
    Type: Grant
    Filed: December 22, 2004
    Date of Patent: May 26, 2009
    Assignees: Sumitomo Chemical Company, Limited, Hitachi, Ltd.
    Inventors: Shinya Tanaka, Yoshitaka Takezawa, Hiroyuki Takahashi
  • Publication number: 20090123726
    Abstract: The present invention relates to a fiber-reinforced composite material and a method for manufacturing the same, and also relates to a transparent multilayered sheet, a circuit board, and an optical waveguide.
    Type: Application
    Filed: October 14, 2008
    Publication date: May 14, 2009
    Applicants: ROHM CO., LTD., MITSUBISHI CHEMICAL CORPORATION, HITACHI, LTD., PIONEER CORPORATION
    Inventors: Hiroyuki YANO, Junji Sugiyama, Masaya Nogi, Shin-ichiro Iwamoto, Keishin Handa, Akira Nagai, Takao Miwa, Yoshitaka Takezawa, Toshiyuki Miyadera, Takashi Kurihara, Tohru Matsuura, Nobutatsu Koshoubu, Tohru Maruno
  • Publication number: 20090105388
    Abstract: An epoxy resin composition comprising an epoxy compound represented by the formula (1): wherein Ar1, Ar2 and Ar3 each denotes any one of divalent groups represented by the following formulas: a curing agent and an alumina powder, wherein the alumina powder is a mixture of an alumina (A) having D50 of 2 ?m or more and 100 ?m or less, an alumina (B) having D50 of 1 ?m or more and 10 ?m or less, and an alumina (C) having D50 of 0.01 ?m or more and 5 ?m or less, in which D50 is a particle size at 50% cumulation from the smallest particle side of a weight cumulative particle size distribution, and the content of the alumina (A), that of the alumina (B) and that of the alumina (C) are respectively 50% by volume or more and 90% by volume or less, 5% by volume or more and 40% by volume or less, and 1% by volume or more and 30% by volume or less, based on the volume of the alumina powder (provided that the total % by volume of the alumina (A), the alumina (B) and the alumina (C) is 100% by volume).
    Type: Application
    Filed: June 6, 2007
    Publication date: April 23, 2009
    Inventors: Shinya Tanaka, Yoshitaka Takezawa, Keiji Fukushima
  • Patent number: 7504720
    Abstract: A semiconductor device includes a semiconductor chip and leads electrically connected to the electrodes of the semiconductor chip. A hollow radiator base houses the semiconductor device which is molded with high-thermal-conductivity resin having an electrical insulating property. The radiator base has a cooling-medium channel therein or radiating fins on the outside. Alternatively, the radiator base is housed in a second radiator base.
    Type: Grant
    Filed: August 17, 2006
    Date of Patent: March 17, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Kinya Nakatsu, Hideki Miyazaki, Yoshitaka Takezawa, Toshiaki Ishii, Hiroshi Hozoji
  • Patent number: 7455901
    Abstract: There is provided a fiber-reinforced composite material containing fibers having an average fiber diameter of 4 to 200 nm and a matrix material, the composite material having a visible light transmittance of 60% or more at a wavelength of 400 to 700 nm, which is a conversion value based on a thickness of 50 ?m. A fiber-reinforced composite material composed of a matrix material and a fiber aggregate impregnated therewith is provided, in which when a segment length of a bright region corresponding to a pore region of the fiber aggregate is represented by L, which is obtained by statistical analysis of a unidirectional run-length image formed from a binary image obtained by binarization of a scanning electron microscopic image of the fiber aggregate, the total length of segments that satisfy L?4.5 ?m is 30% or less of the total analyzed length.
    Type: Grant
    Filed: January 18, 2006
    Date of Patent: November 25, 2008
    Assignees: Kyoto University, Rohm Co., Ltd., Mitsubishi Chemical Corporation, Hitachi, Ltd., Pioneer Corporation
    Inventors: Hiroyuki Yano, Junji Sugiyama, Masaya Nogi, Shin-ichiro Iwamoto, Keishin Handa, Akira Nagai, Takao Miwa, Yoshitaka Takezawa, Toshiyuki Miyadera, Takashi Kurihara, Tohru Matsuura, Nobutatsu Koshoubu, Tohru Maruno
  • Publication number: 20080199987
    Abstract: Improvement in the reliability of a semiconductor device is aimed at. By heating a lead frame, after preparing a lead frame with a tape, until a resin molding is performed, at the temperature 160 to 300° C. (preferably 180 to 300° C.) for a total of more than 2 minutes in the atmosphere which has oxygen, crosslinkage density becoming high in resin of adhesives, a low molecular compound volatilizes and jumps out outside, therefore as a result, since a low molecular compound does not remain in resin of adhesives, the generation of copper migration can be prevented.
    Type: Application
    Filed: April 16, 2008
    Publication date: August 21, 2008
    Inventors: Fujio ITO, Hiromichi Suzuki, Akihiko Kameoka, Junpei Kusukawa, Yoshitaka Takezawa
  • Patent number: 7374973
    Abstract: Improvement in the reliability of a semiconductor device is aimed at. By heating a lead frame, after preparing a lead frame with a tape, until a resin molding is performed, at the temperature 160 to 300° C. (preferably 180 to 300° C.) for a total of more than 2 minutes in the atmosphere which has oxygen, crosslinkage density becoming high in resin of adhesives, a low molecular compound volatilizes and jumps out outside, therefore as a result, since a low molecular compound does not remain in resin of adhesives, the generation of copper migration can be prevented.
    Type: Grant
    Filed: July 15, 2005
    Date of Patent: May 20, 2008
    Assignee: Renesas Technology Corp.
    Inventors: Fujio Ito, Hiromichi Suzuki, Akihiko Kameoka, Junpei Kusukawa, Yoshitaka Takezawa
  • Patent number: 7279574
    Abstract: The present invention provides a novel epoxy compound, which can be converted into a cured epoxy resin product having liquid crystal properties by curing with a curing agent. Since the cured epoxy resin product of the present invention exhibits good heat conductivity, it is also useful as an insulating material requiring high heat releasability such as a printed circuit substrate and the like.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: October 9, 2007
    Assignees: Sumitomo Chemical Company, Limited, Hitachi, Ltd.
    Inventors: Shinya Tanaka, Yoshitaka Takezawa, Hiroyuki Takahashi
  • Publication number: 20070184280
    Abstract: Novel epoxy compounds represented by the general formula (1) wherein Ar1, Ar2 and Ar3 are each optionally substituted phenylene, cyclohexanyl or the like, R1, R2, R3, R4, R5 and R6 are each hydrogen or alkyl of 1 to 18 carbon atoms, and Q1 and Q2 are each alkylene of 1 to 9 carbon atoms or the like, which are useful as the raw material of cured epoxy resins exhibiting liquid crystallinity; a process for the production thereof; and compositions containing the compounds.
    Type: Application
    Filed: December 22, 2004
    Publication date: August 9, 2007
    Inventors: Shinya Tanaka, Yoshitaka Takezawa, Hiroyuki Takahashi