A phosphor for low-pressure discharge lamps is disclosed, wherein the phosphor is present in the form of phosphor grains coated with a protective layer, wherein the protective layer consists of a metal oxide, a metal borate, a metal phosphate or mixtures thereof.

A phosphor for low-pressure discharge lamps is disclosed, wherein the phosphor is present in the form of phosphor grains coated with a protective layer, wherein the protective layer consists of a metal oxide, a metal borate, a metal phosphate or mixtures thereof.

In different embodiments, a low-pressure discharge lamp (1) is provided. The low-pressure discharge lamp has a discharge vessel (2) and a coating structure (7). The coating structure is formed on an inner face of the discharge vessel (2). The coating structure (7) has first fluorescent particles (34) which have at least one fluorescent substance that emits red light and the average particle size of which ranges from 0.5 m to 1.9 m, second fluorescent particles (36) which have at least one fluorescent substance that emits green light and the average particle size of which ranges from 0.6 m to 2.8 m or from 1 m to 4 m, and third fluorescent particles (38) which have at least one fluorescent substance that emits blue light and the average particle size of which ranges from 1 m to 4 m.

In different embodiments, a low-pressure discharge lamp (1) is provided. The low-pressure discharge lamp has a discharge vessel (2) and a coating structure (7). The coating structure is formed on an inner face of the discharge vessel (2). The coating structure (7) has first fluorescent particles (34) which have at least one fluorescent substance that emits red light and the average particle size of which ranges from 0.5 m to 1.9 m, second fluorescent particles (36) which have at least one fluorescent substance that emits green light and the average particle size of which ranges from 0.6 m to 2.8 m or from 1 m to 4 m, and third fluorescent particles (38) which have at least one fluorescent substance that emits blue light and the average particle size of which ranges from 1 m to 4 m.

The invention relates to a luminescent converter (10, 12) for a phosphor-enhanced light source (100, 102, 104). The luminescent converter comprises a first luminescent material (20) configured for absorbing at least a part of excitation light (hv0) emitted by a light emitter (40, 42) of the phosphor-enhanced light source, and for converting at least a part of the absorbed excitation light into first emission light (hv1) comprising a longer wavelength compared to the excitation light. The luminescent converter further comprising a second luminescent material (30) comprising organic luminescent material (30) and configured for absorbing at least a part of the first emission light emitted by the first luminescent material, and for converting at least a part of the absorbed first emission light into second emission light (hv2) having a longer wavelength compared to the first emission light. An effect of the luminescent converter according to the invention is that the two-step light conversion according to the invention generates a relatively small Stokes shift of the light emitted by the organic luminescent material. The inventors have found that by reducing the Stokes shift of the organic luminescent material, the width of the spectrum of the second emission light is limited to reduce an infrared part in the emission spectrum. As such, the efficiency is improved.

The invention relates to a luminescent converter (10, 12) for a phosphor-enhanced light source (100, 102, 104). The luminescent converter comprises a first luminescent material (20) configured for absorbing at least a part of excitation light (hv0) emitted by a light emitter (40, 42) of the phosphor-enhanced light source, and for converting at least a part of the absorbed excitation light into first emission light (hv1) comprising a longer wavelength compared to the excitation light. The luminescent converter further comprising a second luminescent material (30) comprising organic luminescent material (30) and configured for absorbing at least a part of the first emission light emitted by the first luminescent material, and for converting at least a part of the absorbed first emission light into second emission light (hv2) having a longer wavelength compared to the first emission light. An effect of the luminescent converter according to the invention is that the two-step light conversion according to the invention generates a relatively small Stokes shift of the light emitted by the organic luminescent material. The inventors have found that by reducing the Stokes shift of the organic luminescent material, the width of the spectrum of the second emission light is limited to reduce an infrared part in the emission spectrum. As such, the efficiency is improved.

The invention regards an apparatus for promoting D-vitamin production in a living organism, comprising at least one lamp assembly, said at least one lamp assembly is adapted to emit polychromatic light, wherein the polychromatic light at least emulates natural light and UV light at wavelengths between 270 nm and 315 nm.

An ultraviolet light emitting device includes: a first substrate; a second substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on a first main surface of the first substrate; a dielectric layer that is located in a first region directly or indirectly on the first main surface of the first substrate and covers the electrodes, the dielectric layer being not located in a second region directly or indirectly on the first main surface of the first substrate, the second region being different from the first region, the first region including regions in which the electrodes are located; and a light-emitting layer that is located in the second region and/or located directly or indirectly on at least one of second and third main surfaces of the second substrate and emits the ultraviolet light in the gas due to electrical discharge between the electrodes.

An ultraviolet light emitting device includes: a first substrate; a second substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on a first main surface of the first substrate; a dielectric layer that is located in a first region directly or indirectly on the first main surface of the first substrate and covers the electrodes, the dielectric layer being not located in a second region directly or indirectly on the first main surface of the first substrate, the second region being different from the first region, the first region including regions in which the electrodes are located; and a light-emitting layer that is located in the second region and/or located directly or indirectly on at least one of second and third main surfaces of the second substrate and emits the ultraviolet light in the gas due to electrical discharge between the electrodes.

An ultraviolet light emitting device comprises: a first substrate having a main surface; a second substrate facing the main surface of the first substrate; a gas in a space between the first substrate and the second substrate; electrodes directly or indirectly on the main surface of the first substrate; a dielectric layer that is located directly or indirectly on the main surface of the first substrate and covers the electrodes; and a first light-emitting layer. The first light-emitting layer is located directly or indirectly on the dielectric layer and emits ultraviolet light in the gas due to electrical discharge between the electrodes. The first light-emitting layer is thicker in first regions on the dielectric layer than in second regions. The second regions include at least part of regions directly above the electrodes.