Ngk Spark Plug Company, Limited

Yusuke Katsu

Takeshi Mitsuoka

Jun Moteki

Tsuneyuki Ito

Shohei Takaku

Yuki Shimura

Kuniharu Tanaka

Tomoo Tanaka

Hideto Yamada

Shinji Ban

Toshiaki Kurahashi

Yosuke Yatsuya

Hiroshi Yonekura

Syohei Takaku

Yoshito Kojima

Yoshihiro Kuroki

Hironobu Kusanagi

One aspect of the disclosure provides an optical wavelength conversion member including a polycrystalline ceramic sintered body containing, as main components, AlOcrystal grains and crystal grains represented by formula (Y,A)BO:Ce. In the optical wavelength conversion member, a (Y,A)BO:Ce crystal grain has a region wherein the A concentration of a peripheral portion of the (Y,A)BO:Ce crystal grain is higher than that of an interior portion of the (Y,A)BO:Ce crystal grain. Thus, the optical wavelength conversion member exhibits high fluorescence intensity (i.e., high emission intensity) and high heat resistance (i.e., low likelihood of temperature quenching). The optical wavelength conversion member has a structure wherein the element A concentration of a peripheral portion of a (Y,A)BO:Ce crystal grain differs from that in an interior portion of the crystal grain. This structure can achieve a ceramic fluorescent body exhibiting superior fluorescent characteristics and superior thermal characteristics with varied colors of emitted light.

Optical wavelength conversion member and light-emitting device

An optical wavelength converter () is configured such that an optical wavelength conversion member () is bonded to a heat dissipation member () having superior heat dissipation property. Thus, heat generated by light incident on the optical wavelength conversion member () can be efficiently dissipated. Therefore, even when high-energy light is incident on the optical wavelength converter, temperature quenching is less likely to occur, and thus high fluorescence intensity can be maintained. An intermediate film () is disposed between a reflective film () and a bonding portion (). The presence of the intermediate film () improves the adhesion between the reflective film () and the bonding portion (), thereby enhancing the heat dissipation from the optical wavelength conversion member () to the heat dissipation member (). Thus, the temperature quenching of the optical wavelength conversion member () can be prevented, thereby enhancing fluorescence intensity.

Optical wavelength converter and composite optical device

Provided is a ceramic sintered body having high wear resistance and chipping resistance. Also provided are an insert, a cutting tool and a friction stir welding tool, each of which uses such a high-performance ceramic sintered body. The ceramic sintered body includes AlO(alumina), WC (tungsten carbide) and ZrO(zirconia), wherein Zr (zirconium) element is present at either one or both of: (1) a grain boundary between crystal grains of the AlO; and (2) a grain boundary of crystal grains of the AlO and crystal grains of the WC, wherein the ceramic sintered body contains 55.0 to 97.5 vol % of the WC, 0.1 to 18.0 vol % of the ZrO, and the balance being the AlO, and wherein the ZrOis in a phase of tetragonal structure (T) or a mixed phase of tetragonal structure (T) and monoclinic structure (M).

Ceramic sintered body, insert, cutting tool, and friction stir welding tool

An optical wavelength conversion device includes an optical wavelength conversion member configured to convert the wavelength of incident light; a heat dissipation member which is more excellent in heat dissipation than the optical wavelength conversion member; and a joint portion which joins the optical wavelength conversion member and the heat dissipation member together. The optical wavelength conversion member includes a plate-shaped ceramic fluorescent body and a reflecting film disposed on a heat dissipation member-side surface of the ceramic fluorescent body. The joint portion has a thermal conductivity of 120 W/mK or more. The joint portion has a melting point of 240&#xb0; C. or higher.

Optical wavelength conversion device

An optical wavelength conversion member () provided with a ceramic plate () which is configured from a polycrystalline body that is mainly composed of AlOand a component represented by ABO:Ce; and each of A and B in ABOrepresents at least one element selected from the element groups described below. In addition, a dielectric multilayer film () which transmits a specific wavelength and reflects another specific wavelength is formed on a light incident surface () of the ceramic plate (). The ceramic plate () has a porosity of 2% by volume or less, while having an average surface roughness (an arithmetic mean roughness Sa) of 0.5 &#x3bc;m or less. A: Sc, Y and lanthanoids (excluding Ce) B: Al and Ga. Also disclosed is a light-emitting device including the optical wavelength conversion member.

Light wavelength conversion member and light emitting device

A method for producing an optical wavelength conversion member () composed of a sintered body containing, as main components, AlOand a component represented by formula ABO:Ce; an optical wavelength conversion member; an optical wavelength conversion component including the optical wavelength conversion member; and a light-emitting device including the optical wavelength conversion member or the optical wavelength conversion component. The production method of the sintered body includes firing in a firing atmosphere having a pressure of 10Pa or more and an oxygen concentration of 0.8 vol. % or more and less than 25 vol. %.

Method for producing light wavelength conversion member, light wavelength conversion member, light wavelength conversion component and light emitting device

An optical wavelength conversion member and a light-emitting device including the optical wavelength conversion member. The light-emitting device () includes a container (), a light-emitting element (), and an optical wavelength conversion member (). The optical wavelength conversion member () is composed of a polycrystalline ceramic sintered body containing, as main components, AlOcrystal grains and crystal grains of a component represented by formula ABO:Ce. Specifically, A and B of the ABOindividually represent at least one element selected from the following element groups: A: Sc, Y, and lanthanoids (except for Ce), and B: Al and Ga; the at least one element selected from the element groups is present in each crystal grain and the crystal grain boundary of the ceramic sintered body; and the element concentration of the crystal grain boundary is higher than the element concentration of the crystal grain.

The durability of a ceramic sintered body is improved, and a reduction in its light emission intensity and the occurrence of a chromaticity variation are suppressed. The ceramic sintered body contains alumina and a compound represented by M1M2M3O. The volume percent of the compound in the ceramic sintered body is from 3% to 70% inclusive. The ratio of the intensity of XRD from a complex oxide of aluminum and M2 to the intensity of XRD from the compound in the ceramic sintered body is less than 0.05. The average grain diameter of the alumina contained in the ceramic sintered body is from 0.30 (&#x3bc;m) to 3.00 (&#x3bc;m) inclusive. M1 is at least one selected from Sc, Y, and lanthanoid elements, and M2 is at least one selected from lanthanoid elements except any lanthanoid element selected for M1. M3 is at least one of Al and Ga, and X is from 0.003 to 0.500 inclusive.

Ceramic sintered body

An optical wavelength conversion member and a light-emitting device including the optical wavelength conversion member. The optical wavelength conversion member () is formed of a ceramic sintered body having a fluorescent phase containing fluorescent crystal grains as a main component and a translucent phase containing translucent crystal grains as a main component. Crystal grains of the fluorescent phase have a composition represented by formula ABO:Ce, where the element A is selected from Sc, Y, and lanthanoids (except for Ce), and the element B is selected from Al and Ga. In the optical wavelength conversion member (), 0.3&#x3c;a&#x3c;34 and 300 &#x3bc;m&#x3c;y&#x3c;1,050 &#x3bc;m are satisfied, wherein a represents the area ratio of the translucent phase to the fluorescent phase in a cross section of the optical wavelength conversion member (), and y represents the interfacial length of the fluorescent phase.

An optical wavelength conversion member including a polycrystalline ceramic sintered body containing, as main components, AlOcrystal grains and crystal grains of a component represented by formula ABO:Ce, wherein A is at least one element selected from Sc, Y and lanthanoids (except for Ce), and B is at least one element selected from Al and Ga. Further, the following relations are satisfied: 0%&#x2264;X&#x2264;25%, 9%&#x2264;Y&#x2264;45%, and 48%&#x2264;Z&#x2264;90%, wherein X represents a proportion corresponding to the ratio a/N, Y represents a proportion corresponding to the ratio b/N, and Z represents a proportion corresponding to the ratio c/N and a, b, c and N are as defined herein. Also disclosed is a light-emitting device including the optical wavelength conversion member.

Light wavelength conversion member and light emission device

In a ceramic composition mainly composed of alumina (AlO), tungsten carbide (WC) and zirconia (ZrO), zirconium (Zr) is distributed in a first grain boundary as an interface where an alumina (AlO) crystal grain is adjacent to a tungsten carbide (WC) crystal grain and in a second grain boundary as an interface where two alumina (AlO) crystal grains are adjacent to each other.

Ceramic composition and cutting tool

A ceramic sintered body includes tungsten carbide, zirconia, and alumina. The content of the tungsten carbide is 20 to 50 vol %, and the content of the zirconia is 5 to 25 vol %. The crystal phase of the zirconia is a tetragonal crystal or a mixture of tetragonal and monoclinic crystals. The ceramic sintered body does not substantially include Ti compounds. The average particle diameter of the tungsten carbide, the average particle diameter of the zirconia, and the average particle diameter of the alumina are all 1 &#x3bc;m or less.

A sintered body containing alumina crystal particles and zirconia crystal particles as main components includes the tetragonal crystal particles as the zirconia crystal particles. The zirconia crystal particles satisfy relations 0%&#x2266;A&#x2266;3%, 3%&#x2266;B&#x2266;22% and 77%&#x2266;C&#x2266;96%,where A, B and C are as defined herein.

Growing community of inventors

Komaki, Japan

Yusuke Katsu