Abstract: An yttrium oxide-based sintered body includes yttrium oxide as a predominant component. The sintered body includes aluminum in an amount of 0.1 mass % to 0.5 mass % inclusive as reduced to aluminum oxide, has a metal content of 1,000 ppm or less, the metal excluding yttrium and aluminum, and has a relative density of 98% or higher. By virtue of the yttrium oxide-based sintered body, a plasma resistance comparable to that of a high-purity (99.9%) yttrium oxide sintered body can be achieved. Also, since the relative density is sufficiently high, plasma resistance can be enhanced. As a result, the yttrium oxide-based sintered body can be suitably used as a large-scale member by virtue of excellent mechanical strength.

Abstract: A wavelength conversion member is provided which includes a phosphor layer having an increased pencil hardness and thereby has a reduced risk of breakage such as scattering of fragments of the phosphor layer or separation of the phosphor layer. A substrate 12 is made of sapphire, and a phosphor layer 14 is disposed on the substrate 12 and includes phosphor particles 16 and a light transmissive inorganic material 22. The phosphor layer 14 has a pencil hardness of 5B or above. The high hardness of the phosphor layer 14 reduces the risk of breakage such as the phosphor layer 14 being scattered as fragments or being separated from the substrate 12.

Abstract: Provided are a fluorescent member that has high thermal conductivity, can prevent an increase in temperature of a fluorescent layer, and can maintain their fluorescence performance even during irradiation with high-intensity source light, and a light-emitting device using the fluorescent member. A transmissive-type wavelength conversion member 100 converts light with a wavelength in a specific range to light with a different wavelength and allows light passing through the wavelength conversion member to be used as illuminating light. The wavelength conversion member 100 includes: a substrate 110 that is formed of an inorganic material and allows light to pass through; and a fluorescent material layer 120 disposed on the substrate 110. The fluorescent material layer 120 includes fluorescent material particles 122 that absorb light and emit converted light and a light-transmitting ceramic 121 that bonds the fluorescent material particles 122 together.

Abstract: The invention provides a wavelength conversion member which can draw heat efficiently away from a region that is prone to generating heat under irradiation of light with a high energy density and which can suppress the thermal quenching of phosphor, and provides a method for manufacturing such wavelength conversion members, and a light-emitting device having such a wavelength conversion member.

Abstract: The invention provides a wavelength conversion member and a light emitting device which each has a reduced proportion of voids and transmits less source light without causing a decrease in light conversion efficiency offered by phosphor particles having a large particle size. A wavelength conversion member 100 is configured to convert light with a specific wavelength to light with other wavelength, and includes a substrate 110 including an inorganic material, and a phosphor layer 120 joined to the substrate 110 and including phosphor particles 122 that absorb light and emit converted light and a translucent ceramic 121 that binds the phosphor particles 122 to one another. The phosphor particles 122 include two kinds of particles each having a designated particle size distribution.

Abstract: The invention provides a fluorescent member which has high thermal conductivity and thus can prevent an increase in temperature of a phosphor layer and can maintain fluorescent performance even when irradiated with source light having a high intensity, and provides a light-emitting device having such a member. A reflection-type wavelength converting member 100 converts light with a specific wavelength to light with other wavelength and also reflects the light on a reflection surface to emit the light as illumination light. The wavelength converting member 100 includes a substrate 110 including an inorganic material, and a phosphor layer 120 disposed on the substrate 110 and including phosphor particles 122 that absorb light and emit converted light and a translucent ceramic 121 that binds the phosphor particles 122 to one another. The ratio of the thickness of the phosphor layer 120 to the average particle size of the phosphor particles 122 is less than 30.

Abstract: A wavelength conversion member is provided which includes a phosphor layer having an increased pencil hardness and thereby has a reduced risk of breakage such as scattering of fragments of the phosphor layer or separation of the phosphor layer. A substrate 12 is made of sapphire, and a phosphor layer 14 is disposed on the substrate 12 and includes phosphor particles 16 and a light transmissive inorganic material 22. The phosphor layer 14 has a pencil hardness of 5B or above. The high hardness of the phosphor layer 14 reduces the risk of breakage such as the phosphor layer 14 being scattered as fragments or being separated from the substrate 12.

Abstract: Provided are a fluorescent member that has high thermal conductivity, can prevent an increase in temperature of a fluorescent layer, and can maintain their fluorescence performance even during irradiation with high-intensity source light, and a light-emitting device using the fluorescent member. A transmissive-type wavelength conversion member 100 converts light with a wavelength in a specific range to light with a different wavelength and allows light passing through the wavelength conversion member to be used as illuminating light. The wavelength conversion member 100 includes: a substrate 110 that is formed of an inorganic material and allows light to pass through; and a fluorescent material layer 120 disposed on the substrate 110. The fluorescent material layer 120 includes fluorescent material particles 122 that absorb light and emit converted light and a light-transmitting ceramic 121 that bonds the fluorescent material particles 122 together.

Abstract: The invention provides a wavelength conversion member and a light emitting device which each has a reduced proportion of voids and transmits less source light without causing a decrease in light conversion efficiency offered by phosphor particles having a large particle size. A wavelength conversion member 100 is configured to convert light with a specific wavelength to light with other wavelength, and includes a substrate 110 including an inorganic material, and a phosphor layer 120 joined to the substrate 110 and including phosphor particles 122 that absorb light and emit converted light and a translucent ceramic 121 that binds the phosphor particles 122 to one another. The phosphor particles 122 include two kinds of particles each having a designated particle size distribution.

Abstract: The invention provides a wavelength conversion member which can draw heat efficiently away from a region that is prone to generating heat under irradiation of light with a high energy density and which can suppress the thermal quenching of phosphor, and provides a method for manufacturing such wavelength conversion members, and a light-emitting device having such a wavelength conversion member.

Abstract: The invention provides a fluorescent member which has high thermal conductivity and thus can prevent an increase in temperature of a phosphor layer and can maintain fluorescent performance even when irradiated with source light having a high intensity, and provides a light-emitting device having such a member. A reflection-type wavelength converting member 100 converts light with a specific wavelength to light with other wavelength and also reflects the light on a reflection surface to emit the light as illumination light. The wavelength converting member 100 includes a substrate 110 including an inorganic material, and a phosphor layer 120 disposed on the substrate 110 and including phosphor particles 122 that absorb light and emit converted light and a translucent ceramic 121 that binds the phosphor particles 122 to one another. The ratio of the thickness of the phosphor layer 120 to the average particle size of the phosphor particles 122 is less than 30.