Patents by Inventor Hirofumi Sunahara

Hirofumi Sunahara 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).

  • Patent number: 6395118
    Abstract: The present invention provides a method for readily and efficiently manufacturing a ceramic substrate having an excellent dimensional accuracy and small degree of warp comprising the steps of: preparing a non-sintered multilayer ceramic body formed by laminating ceramic layers and conductor layers; forming a multilayer ceramic body-with constraint layers by adhering a first constraint layer and a second constraint layer on one major surface and the other major surface, respectively, of the multilayer ceramic body, the first and second constraint layers being prepared by dispersing a ceramic powder that is not sintered under the sintering condition of the multilayer ceramic body; firing the multilayer ceramic body with the constraint layers under the firing condition of the multilayer ceramic body; and removing the first constraint layer and the second constraint layer after sintering the multilayer ceramic body, wherein the thickness of the first constraint layer is made to be larger than the thickness of the
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: May 28, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Sadaaki Sakamoto, Hirofumi Sunahara
  • Publication number: 20020050316
    Abstract: A method for manufacturing a multilayer ceramic substrate includes a firing step wherein low-temperature-sinterable ceramic material contained in green base layers and inorganic material contained in green constraining layers chemically react each other, whereby a reaction layer is formed along an interface between the green base layer and the green constraining layer. The reaction layer acts to enhance a bonding force between the green base layer and the green constraining layer.
    Type: Application
    Filed: August 30, 2001
    Publication date: May 2, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Sadaaki Sakamoto, Hirofumi Sunahara, Hiroshi Takagi
  • Patent number: 6372676
    Abstract: A ceramic substrate composition includes about 26 to 48% by weight of a CaO—Al2O3—B2O3—SiO2 type glass, about 35 to 68% by weight of at least one of alumina, mullite, cordierite and forsterite, and about 3 to 24% by weight of quartz, said glass being capable of being crystallized to wollastonite by firing of the composition at a temperature of about 800 to 1000° C. A ceramic circuit component contains a circuit formed on the ceramic substrate obtained by firing the composition.
    Type: Grant
    Filed: May 24, 1999
    Date of Patent: April 16, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Kazuo Kishida, Hirofumi Sunahara, Mitsuyoshi Nishide, Hiroshi Takagi
  • Publication number: 20020026978
    Abstract: A multilayer ceramic substrate three-dimensionally including functional elements is provided. The functional elements, for example, a capacitor element, an inductor element or a resistor element, are prepared using plate-like sintered plates produced by firing ceramic functional material beforehand. These functional elements are included in an unsintered composite laminate. The unsintered composite laminate is provided with green layers for the substrate, restriction layers including sintering-resistant materials, and wiring conductors, and when it is fired, the green layers for substrate are prevented from shrinking in the direction of primary faces due to the function of the restriction layers. Therefore, the unsintered composite laminate can be fired without problems while the functional elements are included, and mutual diffusion does not occur between the functional elements and the green layers for substrate, so that the characteristics of the functional elements can be maintained even after firing.
    Type: Application
    Filed: August 27, 2001
    Publication date: March 7, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Hideyuki Harada, Hirofumi Sunahara, Hiroshi Takagi, Yukio Sakabe
  • Publication number: 20020027282
    Abstract: A composite monolithic electronic component has a laminate including a base layer having a relative dielectric coefficient of about 10 or less and a functional layer which is at least one of a high-dielectric-coefficient layer having a relative dielectric coefficient of about 15 or more and a magnetic layer. The base layer contains a crystallized glass containing SiO2, MgO, Al2O3 and B2O3, and a ceramic oxide having a thermal expansion coefficient of about 6.0 ppm/° C. or more. The functional layer contains an amorphous glass having a softening point of about 800° C. or less.
    Type: Application
    Filed: June 8, 2001
    Publication date: March 7, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Hiromichi Kawakami, Hirofumi Sunahara
  • Publication number: 20010022416
    Abstract: A method of manufacturing a multilayer ceramic device includes forming first and second glass-ceramic green sheets from a ceramic material containing glass by laminating the material to form a green sheet laminate having a cavity with an open surface at one surface thereof. Then, shrinkage-suppressing layers which are formed with shrinkage-suppressing inorganic material having a higher sintering temperature than the ceramic material are applied over the surfaces of the green sheet laminate. Thus, a composite laminate is obtained. Then, the composite laminate is pressed in the laminating direction such that the bottom portion of the cavity receives the same amount of pressure as the surrounding region of the cavity via an opening. Then, the composite laminate is fired, and the shrinkage-suppressing layers are removed.
    Type: Application
    Filed: December 28, 2000
    Publication date: September 20, 2001
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Hideyuki Harada, Hideaki Nakai, Hirofumi Sunahara, Hiroshi Takagi
  • Patent number: 6270880
    Abstract: Provided is a crystalline glass composition for use in a circuit board that can be sintered at a temperature of 1100° C. and is endowed with favorable characteristics such as a relative dielectric constant of as low as ½ and a thermal expansion coefficient of as high as 12 ppm/° C. as an electrical insulating insulator for use in a circuit board. The crystalline glass composition contains SiO2, MgO and CaO, the composition ratio of SiO2, MgO and CaO in % by weight falling within an area surrounded by the lines connecting the points A (25, 45, 30), B (25, 0, 75), C (44, 0, 56), D (44, 22, 34), E (40, 19, 41) and F (29, 40, 31) in a ternary phase diagram wherein at least one melwinite, monticellite or calcium silicate crystalline phase is deposited by heat-treating the composition. A ceramic powder having a thermal expansion coefficient of about 6.0 ppm/C or more is sometimes added in the powder comprising the glass composition.
    Type: Grant
    Filed: October 15, 1999
    Date of Patent: August 7, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hiromichi Kawakami, Hirofumi Sunahara, Toshiki Tanaka, Shizuharu Watanabe, Hiroshi Takagi
  • Patent number: 6241838
    Abstract: A method of producing a multi-layer ceramic substrate involves the steps of preparing compact blocks including a raw ceramic functional material to be the passive component, preparing a raw composite laminated member having a plurality of laminated ceramic green sheets containing a ceramic insulating material and wiring conductors and preliminarily providing spaces in the inside such that the compact blocks fit into the spaces, arranging sheet type bases made from a raw ceramic not sintered at the baking temperature of the composite laminated member on the principal plane at both ends with respect to the lamination direction of the raw composite laminated member, baking the raw composite laminated member with the raw composite laminated member interposed by the sheet type bases so as to restrain the contraction at a temperature not more than about 1000° C., and eliminating the unsintered sheet type bases.
    Type: Grant
    Filed: August 26, 1998
    Date of Patent: June 5, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Sadaaki Sakamoto, Hirofumi Sunahara, Hiroshi Takagi, Yukio Sakabe
  • Patent number: 6231986
    Abstract: An inorganic composition for low temperature firing comprising about 15 to 40 weight % of glass powder and about 60 to 85 weight % of cordierite, is disclosed. The glass powder is composed of about 20 to 60 weight % of SiO2, about 30 to 50 weight % of B2O3, about 5 to 30 weight % of MgO, 0 to about 15 weight % of Al2O3, and about 1 to 5 weight % of R2O (R is alkali metal). The inorganic composition is capable of being fired at a relative low temperature, and has a low thermal expansion coefficient and permittivity, as well as high mechanical strength.
    Type: Grant
    Filed: July 23, 1997
    Date of Patent: May 15, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yasutaka Sugimoto, Kazuo Kishida, Hirofumi Sunahara, Hiroshi Takagi
  • Patent number: 6228196
    Abstract: The invention provides a method of producing a multi-layer ceramic substrate comprising a laminated member having a plurality of ceramic layers made of a ceramic insulating material and a wiring conductor, comprising the steps of: preparing a raw compact having the plurality of the laminated ceramic green sheets containing the ceramic insulating material and the wiring conductor; providing raw sheet type bases on the principal plane at both ends with respect to the lamination direction of the raw compact, the raw sheet type bases containing a ceramic not to be sintered at the baking temperature of the raw compact; baking the raw compact in the state interposed between the sheet type bases so as to obtain the laminated member; and eliminating the unsintered sheet type bases; wherein the heat expansion coefficient difference of the sheet type bases and the laminated member after baking is 2.5×10−6 degK−1 or more.
    Type: Grant
    Filed: May 21, 1999
    Date of Patent: May 8, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Sadaaki Sakamoto, Hirofumi Sunahara, Mitsuyoshi Nishide
  • Patent number: 6153290
    Abstract: The present invention provides a method for producing a high-density multi-layer ceramic substrate with stable characteristics, the substrate incorporating therein a passive component such as a high-precision capacitor or inductor. The method comprises the steps of providing compact blocks containing a green ceramic functional material to form the passive components; providing a composite green laminate having a plurality of ceramic green sheets comprising a ceramic insulating material and in which the compact blocks are built in pre-disposed spaces and a paste containing a metal inducing, during firing, oxidation reaction accompanied by expansion is provided in space between inside walls of the spaces and the compact blocks; firing the composite green laminate in a state in which the laminate is sandwiched by the sheet-like supports formed of green ceramics that cannot be sintered at the sintering temperature, so as to prevent shrinkage of the laminate; and removing the unsintered sheet-like supports.
    Type: Grant
    Filed: December 28, 1998
    Date of Patent: November 28, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Hirofumi Sunahara
  • Patent number: 6108192
    Abstract: A dielectric ceramic composition is formed of a mixture including a BaO--TiO.sub.2 --REO.sub.3/2 ceramic composition, wherein RE represents a rare earth element, and a glass composition containing about 13-50 wt. % SiO.sub.2, about 3-30 wt. % B.sub.2 O.sub.3, about 40-80 wt. % alkaline earth metal oxide and about 0.5-10 wt. % Li.sub.2 O. The dielectric ceramic composition has a high dielectric constant and a high Q value, as well as excellent temperature stability, and is capable of being sintered at a relatively low temperature. The dielectric ceramic composition is advantageously used in ceramic electronic parts.
    Type: Grant
    Filed: December 11, 1998
    Date of Patent: August 22, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yasutaka Sugimoto, Hirofumi Sunahara, Kimihide Sugou, Hiroshi Takagi
  • Patent number: 6094111
    Abstract: An inductance-capacitance (LC) composite component comprising a body obtained by monolithically sintering a capacitor portion having a layered structure consisting of a dielectric ceramic layer and an electrode layer with an inductor portion having a layered structure consisting of a magnetic ceramic layer and an electrode layer, wherein at least one of said dielectric ceramic layer and said magnetic layer contains a glass having a softening point of 800.degree. C. or lower, and said dielectric ceramic layer and said magnetic layer are monolithically sintered at a temperature of 1,000.degree. C. or lower. The LC composite component is free from generation of cracks and degradation in characteristics, and is thereby highly reliable.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: July 25, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Hirofumi Sunahara