Denka Company Limited

Denki Kagaku Kogyo Kabushiki Kaisha

Kohki Ichikawa

Atsushi Sakai

Hideki Hirotsuru

Yoshitaka Taniguchi

Keita Kobayashi

Suzuya Yamada

Yasuhito Fushii

Takeshi Gotoh

Hiroshi Murata

Hideyuku Emoto

Shuji Sasaki

Yuzo Nakamura

A powder mixture including spherical barium titanate particles and spherical oxide particles and having an average particle diameter of 2 &#x3bc;m or more and 30 &#x3bc;m or less, wherein the spherical oxide particles have an average particle diameter of 0.05 &#x3bc;m or more and 1.5 &#x3bc;m or less, and the spherical oxide particles are contained in an amount of 0.02% by mass or more and 15% by mass or less based on the powder mixture. The spherical oxide particles are preferably amorphous silicon dioxide particles and/or aluminum oxide particles. According to the present invention, it is possible to provide a spherical barium titanate-based powder which enables to prepare a high dielectric resin composition with which reduced wire sweep amount and burr are achieved.

Powder mixture

A ceramic circuit board includes a ceramic substrate and metal layers provided to both surfaces of the ceramic substrate and containing Al and/or Cu, wherein a measurement value &#x3b1;1 of a linear thermal expansion coefficient at 25&#xb0; C. to 150&#xb0; C. is 5&#xd7;10to 9&#xd7;10/K, a ratio &#x3b1;1/&#x3b1;2 of the &#x3b1;1 to a theoretical value &#x3b1;2 of the linear thermal expansion coefficient at 25&#xb0; C. to 150&#xb0; C. is 0.7 to 0.95, and at least one of the metal layers forms a metal circuit.

Ceramic circuit board

A power module includes a base plate, a ceramic insulating substrate bonded on the base plate, and a semiconductor element bonded on the ceramic insulating substrate, wherein a surface of the base plate on a side opposite to the ceramic insulating substrate has a warp with a convex shape, and a linear thermal expansion coefficient &#x3b1;1 (&#xd7;10/K) of the base plate and a linear thermal expansion coefficient &#x3b1;2 (&#xd7;10/K) of the ceramic insulating substrate when a temperature decreases in the range of 25&#xb0; C. to 150&#xb0; C. satisfy the following Expression (1). 

Power module

A high-brightness phosphor having high-temperature characteristics and long-term reliability, and a white light-emitting device using this phosphor are provided. The phosphor contains a silicate phosphor (A) having a peak wavelength of at least 525 nm but not higher than 535 nm and fluorescence intensity of at least 250% but not higher than 270%; an oxynitride phosphor (B) having a peak wavelength of at least 540 nm but not higher than 545 nm and fluorescence intensity of at least 260% but not higher than 280%; and an nitride phosphor (C) having a peak wavelength of at least 615 nm but not higher than 625 nm, wherein the amount of the silicate phosphor (A) is at least 20% but not higher than 35% by mass, the amount of the oxynitride phosphor (B) is at least 50% but not higher than 70% by mass, and the amount of the nitride phosphor (C) is at least 10% but not higher than 20% by mass.

Phosphor and light-emitting device

A high-brightness phosphor having high-temperature characteristics and long-term reliability, and a white light-emitting device using this phosphor are provided. The phosphor contains a silicate phosphor (A) having a peak wavelength of at least 525 nm but not higher than 535 nm and fluorescence intensity of at least 250% but not higher than 270%; an oxynitride phosphor (B) having a peak wavelength of at least 540 nm but not higher than 545 nm and fluorescence intensity of at least 260% but not higher than 280%; and an oxynitride phosphor (C) having a peak wavelength of at least 645 nm but not higher than 655 nm, wherein the amount of the silicate phosphor (A) is at least 20% but not higher than 35% by mass, the amount of the oxynitride phosphor (B) is at least 50% but not higher than 70% by mass, and the amount of the oxynitride phosphor (C) is at least 10% but not higher than 20% by mass.

Phosphor for light-emitting device

The present invention relates to a process of producing an aluminum nitride sintered body which satisfies both high thermal conductivity and reduction in the shrinkage factor at the time of sintering. The aluminum nitride sintered body is a sintered body of a powder mixture containing an aluminum nitride powder and a sintering aid, characterized by having a thermal conductivity of at least 190 W/m&#xb7;K and a shrinkage factor represented by the percentage of {(dimensions of the molded body before sintering)&#x2212;(dimensions of the sintered body after sintering)}/(dimensions of the molded body before sintering) of at most 15%.

Process for producing aluminum nitride sintered compacts

To provide an aluminum nitride powder and an aluminum nitride sintered body which satisfy both high thermal conductivity of an aluminum nitride sintered body and reduction in the shrinkage factor at the time of sintering. An aluminum nitride powder characterized in that it has local maximum values in size in regions of from 3 to 15 &#x3bc;m, from 0.5 to 1.5 &#x3bc;m and 0.3 &#x3bc;m or less, the proportions of particles in the respective regions are from 40 to 70%, from 25 to 40% and from 0.5 to 20% on the volume basis, and it has an oxygen amount of from 0.5 to 1.5 mass %. An aluminum nitride sintered body which is a sintered body of a powder mixture containing the above aluminum nitride powder and a sintering aid, characterized by having a thermal conductivity of at least 190 W/m&#xb7;K and a shrinkage factor represented by the percentage of {(dimensions of the molded body before sintering)&#x2212;(dimensions of the sintered body after sintering)}/(dimensions of the molded body before sintering) of at most 15%.

Growing community of inventors

Omuta, Japan

Kohki Ichikawa