A exemplary light emitting device includes an excitation source operable to generate excitation light with a dominant wavelength in a range 450 nm to 470 nm; a red photoluminescence material which generates light with a peak emission wavelength in a range 600 nm to 620 nm with a full width at half maximum emission intensity greater than 70 nm and less than 80 nm; a yellow to green photoluminescence material which generates light with a peak emission wavelength in a range 530 nm to 550 nm; and a narrow-band red photoluminescence material which generates light with a peak emission wavelength in a range 625 nm to 635 nm with a full width at half maximum emission intensity greater than about 5 nm and less than about 25 nm.

A lighting device for emitting a red total radiation may be configured such that the lighting device has a semiconductor layer sequence configured to emit electromagnetic primary radiation. A conversion element may include a first fluorescent material of the formula Sr[Al.sub.2Li.sub.2O.sub.2N.sub.2]:Eu, crystallized in the tetragonal space group P4.sub.2/m. The first fluorescent material may at least partially convert the electromagnetic primary radiation into an electromagnetic secondary radiation in the red region of the electromagnetic spectrum. The conversion element may include a second fluorescent material to at least partially convert the electromagnetic primary radiation into an electromagnetic secondary radiation in the red region of the electromagnetic spectrum and/or the lighting device may include a mirror or filter arranged above the conversion element.

A process for synthesizing a Mn.sup.4+ doped phosphor of formula I by electrolysis is presented. The process includes electrolyzing a reaction solution comprising a source of manganese, a source of M and a source of A. One aspect relates to a phosphor composition produced by the process. A lighting apparatus including the phosphor composition is also provided. A.sub.x[MF.sub.y]:Mn.sup.4+ (I) where, A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7.

Provided are a light-emitting instrument, and an image display device utilizing an AlON phosphor and having wide color gamut. The light-emitting instrument includes an emission source emitting light having a wavelength from 410 nm to 470 nm and a phosphor or a light-transmitting body where the phosphor is dispersed, and the phosphor includes an inorganic compound where an AlON crystal, an AlON solid solution crystal, or an inorganic crystal having a crystal structure identical to AlON includes at least Mn, an A element (a monovalent metal element) it necessary, a D element (a divalent metal element) if necessary, an E element (a monovalent anion) if necessary, and a G element (one or more elements other than Mn, the A, Al, O, N, the D, or the E) if necessary, and emits fluorescence having a peak wavelength from 515 nm to 541 nm upon irradiation of an excitation source.

A process for preparing a Mn.sup.+4 doped phosphor of formula I ##STR00001##
includes gradually adding a first solution comprising a source of M and HF and a second solution comprising a source of Mn to a reactor, in the presence of a source of A and an anion selected from phosphate, sulfate, acetate, and combinations thereof, to form a product liquor comprising the Mn.sup.+4 doped phosphor. The process also includes gradually discharging the product liquor from the reactor while volume of the product liquor in the reactor remains constant. A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MF.sub.y] ion; and y is 5, 6 or 7.

An LED-filament comprising: a partially light-transmissive substrate; a plurality of blue LED chips mounted on a front face of the substrate; first broad-band green to red photoluminescence materials and a first narrow-band manganese-activated fluoride red photoluminescence material covering the plurality of blue LED chips and the front face of the substrate; and second broad-band green to red photoluminescence materials covering the back face of the substrate. The LED-filament can further comprise a second narrow-band manganese-activated fluoride red photoluminescence material on the back face of the substrate in an amount that is less than 5 wt % of a total red photoluminescence material content on the back face of the substrate.

An LED-filament includes a partially light-transmissive substrate; blue LED chips mounted on a front face of the substrate; first broad-band green to red photoluminescence materials and a first narrow-band manganese-activated fluoride red photoluminescence material covering the blue LED chips and the front face of the substrate; and second broad-band green to red photoluminescence materials covering the back face of the substrate. The LED-filament can further include a second narrow-band manganese-activated fluoride red photoluminescence material on the back face of the substrate in an amount that is less than 5 wt % of a total red photoluminescence material content on the back face of the substrate.

A device including an LED light source optically coupled to a green-emitting U.sup.6+-doped phosphor having a composition selected from the group consisting of U.sup.6+-doped phosphate-vanadate phosphors, U.sup.6+-doped halide phosphors, U.sup.6+-doped oxyhalide phosphors, U.sup.6+-doped silicate-germanate phosphors, U.sup.6+-doped alkali earth oxide phosphors, and combinations thereof, is presented. The U.sup.6+-doped phosphate-vanadate phosphors are selected from the group consisting of compositions of formulas (A1)-(A12). The U.sup.6+-doped halide phosphors are selected from the group consisting of compositions for formulas (B1)-(B3). The U.sup.6+-doped oxyhalide phosphors are selected from the group consisting of compositions of formulas (C1)-(C5). The U.sup.6+-doped silicate-germanate phosphors are selected from the group consisting of compositions of formulas (D1)-(D11). The U.sup.6+-doped alkali earth oxide phosphors are selected from the group consisting of formulas (E1)-(E11).

The present invention relates to a process for producing a composite-fluoride fluorescent material represented by the general formula A.sub.2MF.sub.6:Mn.sup.4+ (wherein A is at least one alkali metal element including K; M is one or more metallic elements including at least Si or Ge and selected from among Si, Ge, Sn, Ti, Zr, and Hf; F is fluorine; and Mn is manganese). With the production process, it is possible to obtain a fluorescent material which is high in absorptance, internal quantum efficiency, and external quantum efficiency and has excellent optical properties.

There is provided a display backlight (604), including an excitation source (644) for generating blue light (650); and a wavelength converter (654) being a unitary construction including a combination of a wavelength selective filter layer (658) bonded to a photoluminescence layer (660), where the photoluminescence layer (658) includes a green photoluminescence material and a red photoluminescence material; and where the wavelength selective filter layer (658) is transmissive to blue light and reflective to green and red light.