A lighting device comprising a housing arranged with at least one first housing space and at least one second housing space; at least one first illumination module respectively arranged in the at least one or more first housing space and at least one first auxiliary functional module, respectively arranged in the at least one second housing spaces; wherein each of the first auxiliary functional modules includes at least one of a communication module, a sensor module or a camera module. The lighting device arranged according to an embodiment of the present invention not only satisfies the lighting demand of existing urban planning, but also facilitates the upgrading of intelligent lighting devices with such functions as temperature detection, traffic monitoring and alarm, at a low cost.

A light-emitting device includes an optical amplifier and gives off output light from optical amplifier by making a plurality of seed light rays, having mutually different wavelengths, incident on optical amplifier. Optical amplifier includes a medium portion containing a wavelength-converting element. Optical amplifier has wavelength-converting element thereof excited by excitation light to produce a plurality of partially coherent light rays, of which wavelengths are respectively the same as the mutually different wavelengths of plurality of seed light rays, thereby giving off, as output light, a multi-wavelength light beam. Excitation light has a shorter wavelength than any of plurality of seed light rays and is incident on the medium portion. Multi-wavelength light beam includes a plurality of light rays amplified. Plurality of light rays amplified have wavelengths, which are respectively the same as mutually different wavelengths of plurality of seed light rays.

A photoconversion device includes a wavelength converter including a plurality of phosphor areas, a drive, and a controller. The plurality of phosphor areas includes a first phosphor area to emit fluorescence with a first wavelength spectrum in response to excitation light and a second phosphor area to emit fluorescence with a second wavelength spectrum different from the first wavelength spectrum in response to the excitation light. The drive changes an illuminating area to receive the excitation light in the plurality of phosphor areas. The controller drives the drive to change the illuminating area in the plurality of phosphor areas and stop driving the drive to define the illuminating area in the plurality of phosphor areas.

A fluorescent plate including a fluorescent phase which emits fluorescence by excitation light, and a plurality of voids, wherein, in a cross section of the fluorescent plate including cross sections of the voids, voids having an equivalent circle diameter of 0.4 micrometers or greater and 50 micrometers or smaller have a standard deviation in equivalent circle diameter of 1.5 or less.

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 fluorescent plate includes a fluorescent phase which emits fluorescence by excitation light, a light-transmitting phase which allows passage of the excitation light, and a plurality of voids surrounded by the fluorescent phase and the light-transmitting phase, wherein, in a cross section of the fluorescent plate including cross sections of the voids, an average ratio of a portion of the circumference of a void, which portion is in contact with the fluorescent phase to the entire circumference of the void, is higher than an area ratio of the area of the fluorescent phase present in the fluorescent plate to the total area of the fluorescent phase and the light-transmitting phase present in the fluorescent plate.

A fluorescent plate includes a fluorescent phase which emits fluorescence by excitation light, a light-transmitting phase which allows passage of the excitation light, and a plurality of voids surrounded by the fluorescent phase and the light-transmitting phase, wherein, in a cross section of the fluorescent plate including cross sections of the voids, an average ratio of a portion of the circumference of a void, which portion is in contact with the fluorescent phase to the entire circumference of the void, is higher than an area ratio of the area of the fluorescent phase present in the fluorescent plate to the total area of the fluorescent phase and the light-transmitting phase present in the fluorescent plate.

A wavelength conversion member includes a ceramic fluorescent body for converting a wavelength of incident light, a heat radiation member for radiating heat of the ceramic fluorescent body to an outside atmosphere, and a solder layer for joining together the ceramic fluorescent body and the heat radiation member. The solder layer includes a joining portion disposed between the ceramic fluorescent body and the heat radiation member and a protruding portion protruding outward from an outer circumferential portion of the ceramic fluorescent body. The protruding portion is spaced apart from a side surface formed on the outer circumferential portion of the ceramic fluorescent body. In the solder layer, the maximum value of thickness of the protruding portion is greater than the average value of thickness of the joining portion.

The invention provides a luminescent element (1000) comprising a solid luminescent body (100), wherein the solid luminescent body (100) comprises a luminescent material (200), wherein the luminescent material (200) is configured to generate luminescent material light (201) upon excitation with light having a wavelength where the luminescent material (200) is excitable, wherein the solid luminescent body (100) comprises luminescent body faces (120), wherein the luminescent element (1000) further comprises one or more reflective elements (300) associated to at least one luminescent body face (120), wherein the one or more reflective elements (300) are metallic, and wherein a surface coverage of the at least one luminescent body face (120) with the one or more reflective elements (300) is selected from the range of 5-40%.