One aspect of the disclosure provides an optical wavelength conversion member including a polycrystalline ceramic sintered body containing, as main components, Al.sub.2O.sub.3 crystal grains and crystal grains represented by formula (Y,A).sub.3B.sub.5O.sub.12:Ce. In the optical wavelength conversion member, a (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain has a region wherein the A concentration of a peripheral portion of the (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain is higher than that of an interior portion of the (Y,A).sub.3B.sub.5O.sub.12: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).sub.3B.sub.5O.sub.12: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.

One aspect of the disclosure provides an optical wavelength conversion member including a polycrystalline ceramic sintered body containing, as main components, Al.sub.2O.sub.3 crystal grains and crystal grains represented by formula (Y,A).sub.3B.sub.5O.sub.12:Ce. In the optical wavelength conversion member, a (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain has a region wherein the A concentration of a peripheral portion of the (Y,A).sub.3B.sub.5O.sub.12:Ce crystal grain is higher than that of an interior portion of the (Y,A).sub.3B.sub.5O.sub.12: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).sub.3B.sub.5O.sub.12: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.

The invention provides a light generating device (1000) comprising (i) a plurality of n light sources (100), and (ii) an optical component (1200) comprising an array (200) of prismatic elements (300), wherein: (a) the plurality of n light sources (100) comprise a first subset of one or more first light sources (110) configured to generate collimated first light source light (111) and a second subset of one or more second light sources (120) configured to generate collimated second light source light (121), wherein n>2; (b) the array (200) of prismatic elements (300) is configured in a light receiving relationship with the n light sources (100), wherein the array of prismatic elements (300) comprises k 1 parallel arranged first prismatic faces (201) and k2 parallel arranged second prismatic faces (202), wherein k1>2 and wherein k2>2, wherein the first prismatic faces (201) and the second prismatic faces (202) are not mutually parallel; (c) the first light sources (110) are configured to irradiate the first prismatic faces (201) and the second light sources (120) are configured to irradiate the second prismatic faces (202); and (d) the prismatic elements (300) are configured to reflect or refract the collimated first light source light (111) and the collimated second light source light (121) as coincident beams of first light source light (111) and second light source light (121).

The invention provides a light generating device (1000) comprising (i) a plurality of n light sources (100), and (ii) an optical component (1200) comprising an array (200) of prismatic elements (300), wherein: (a) the plurality of n light sources (100) comprise a first subset of one or more first light sources (110) configured to generate collimated first light source light (111) and a second subset of one or more second light sources (120) configured to generate collimated second light source light (121), wherein n>2; (b) the array (200) of prismatic elements (300) is configured in a light receiving relationship with the n light sources (100), wherein the array of prismatic elements (300) comprises k 1 parallel arranged first prismatic faces (201) and k2 parallel arranged second prismatic faces (202), wherein k1>2 and wherein k2>2, wherein the first prismatic faces (201) and the second prismatic faces (202) are not mutually parallel; (c) the first light sources (110) are configured to irradiate the first prismatic faces (201) and the second light sources (120) are configured to irradiate the second prismatic faces (202); and (d) the prismatic elements (300) are configured to reflect or refract the collimated first light source light (111) and the collimated second light source light (121) as coincident beams of first light source light (111) and second light source light (121).

A light source device includes: a light source having an upper surface including a light-emitting surface, the light source including a plurality of light-emitting parts arranged in a two-dimensional array; a lens located above and spaced apart from the light-emitting surface of the light source, wherein the lens includes an optically functional part, and a flange part located along an outer periphery of the optically functional part; and a support part formed of a light-shielding member and configured to support at least the flange part of the lens.

A light source device includes: a light source having an upper surface including a light-emitting surface, the light source including a plurality of light-emitting parts arranged in a two-dimensional array; a lens located above and spaced apart from the light-emitting surface of the light source, wherein the lens includes an optically functional part, and a flange part located along an outer periphery of the optically functional part; and a support part formed of a light-shielding member and configured to support at least the flange part of the lens.

The present invention relates to a backlight unit for use in a display device. The backlight unit includes a circuit board, at least one light-emitting diode chip mounted on the circuit board, a plurality of reflection members arranged on the upper part of the light-emitting diode chip, and a light diffusing member. The light diffusing member has an incident surface on which light enters and an emitting surface from which light is emitted. The light diffusing member is arranged on the upper part of the circuit board. The plurality of reflection members are stacked on each other and reflect a part of light emitted from the upper surface of the light-emitting diode chip.

A fluorescent plate includes a fluorescent phase which emits fluorescence by excitation light, and a plurality of voids. The plurality of voids include a plurality of particular voids having an equivalent circle diameter of 0.4 micrometers or greater and 50 micrometers or smaller. In a cross section of the fluorescent plate, the ratio of the number of the particular voids having a circularity greater than 0.6 and 1 or less to the total number of the plurality of particular voids is 50% or greater.

A fluorescent plate includes a fluorescent phase which emits fluorescence by excitation light, and a plurality of voids. The plurality of voids include a plurality of particular voids having an equivalent circle diameter of 0.4 micrometers or greater and 50 micrometers or smaller. In a cross section of the fluorescent plate, the ratio of the number of the particular voids having a circularity greater than 0.6 and 1 or less to the total number of the plurality of particular voids is 50% or greater.

A light emitting device including a bulb having a side surface, a board elongated longer in a first direction than in a second direction perpendicular to the first direction, and a plurality of light emitting elements mounted on the board. Each of the plurality of light emitting elements has an upper surface and a lower surface opposite to the upper surface, where the lower surface is mounted on the board. The device includes a plurality of sets of metal plates and leads electrically connected to the plurality of light emitting elements, and a wavelength conversion member covering the light emitting elements and a portion of each of the metal plates. The board, the light emitting elements, the sets of metal plates and leads, and the wavelength conversion member are disposed in the bulb. The upper surface of each of the light emitting elements faces the side surface of the bulb.