A red-luminescent long-afterglow phosphor, represented by Mg.sub.xZn.sub.yGe.sub.zO.sub.3: aMn.sup.2+, bEu.sup.3+, cR.sup.3+. The phosphor is a kind of oxide compound based white powder. The phosphor powder synthesis process is environmentally friendly, no sintering-assisted gas required and no harmful gas generated during or after sintering. The phosphor powder can be excited by UV and is chemically stable.

The present invention provides a light emitting device comprising a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven. The present invention has an advantage in that a light emitting device can be diversely applied in a desired atmosphere and use by realizing white light with different light spectrums and color temperatures. Particularly, the present invention has the effect on health by adjusting the wavelength of light or the color temperature according to the circadian rhythm of humans.

A light emitting device including a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven.

A chip-type light-emitting semiconductor device includes: a substrate 4; a blue LED 1 mounted on the substrate 4; and a luminescent layer 3 made of a mixture of yellow/yellowish phosphor particles 2 and a base material 13 (translucent resin). The yellow/yellowish phosphor particles 2 is a silicate phosphor which absorbs blue light emitted by the blue LED 1 to emit a fluorescence having a main emission peak in the wavelength range from 550 nm to 600 nm, inclusive, and which contains, as a main component, a compound expressed by the chemical formula: (Sr.sub.1-a1-b1-xBa.sub.a1Ca.sub.b1Eu.sub.x).sub.2SiO.sub.4 (0a10.3, 0b10.8 and 0<x<1). The silicate phosphor particles disperse substantially evenly in the resin easily. As a result, excellent white light is obtained.

A light emitting device including a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven.

The present invention discloses a nitroxide fluorescent powder comprising an inorganic compound containing M, A, B, O, N, and R elements; in which the M element is at least one of Ca, Sr, Ba, Mg, Li, Na, and K, the A element is at least one of B, Al, Ga, and In, the B element is at least one of C, Si, Ge, and Sn, the R element is at least one of Ce, Eu, Lu, Dy, Gd, and Ho, characterized in that the inorganic compound forms a crystal in a crystalline phase, and the oxygen atom content in the crystal in a crystalline phase is in an increasing structural distribution from a core to surface of the crystal. The nitroxide fluorescent powder and the nitroxide illuminant of the present invention have the advantages of good chemical stability, good aging and light decay resistance, and high luminescent efficiency, and are useful for various luminescent devices. The preparation method of the present invention is easy and reliable and useful for industrial mass production.

The present invention discloses a nitroxide fluorescent powder comprising an inorganic compound containing M, A, B, O, N, and R elements; in which the M element is at least one of Ca, Sr, Ba, Mg, Li, Na, and K, the A element is at least one of B, Al, Ga, and In, the B element is at least one of C, Si, Ge, and Sn, the R element is at least one of Ce, Eu, Lu, Dy, Gd, and Ho, characterized in that the inorganic compound forms a crystal in a crystalline phase, and the oxygen atom content in the crystal in a crystalline phase is in an increasing structural distribution from a core to surface of the crystal. The nitroxide fluorescent powder and the nitroxide illuminant of the present invention have the advantages of good chemical stability, good aging and light decay resistance, and high luminescent efficiency, and are useful for various luminescent devices. The preparation method of the present invention is easy and reliable and useful for industrial mass production.

Compositions are generally provided that include an oxyfluoride compound. In one embodiment, the oxyfluoride compound has the formula: NaCa.sub.2xA.sub.xGeO.sub.4zF.sub.1yN.sub.z where A is Ba, Sr, or a mixture thereof; 0.01x0.1; 0y0.2; and 0z0.1. Methods of forming such compounds are also generally provided.

The present invention provides a light emitting device comprising a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven. The present invention has an advantage in that a light emitting device can be diversely applied in a desired atmosphere and use by realizing white light with different light spectrums and color temperatures. Particularly, the present invention has the effect on health by adjusting the wavelength of light or the color temperature according to the circadian rhythm of humans.

The present invention provides a light emitting device comprising a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven. The present invention has an advantage in that a light emitting device can be diversely applied in a desired atmosphere and use by realizing white light with different light spectrums and color temperatures. Particularly, the present invention has the effect on health by adjusting the wavelength of light or the color temperature according to the circadian rhythm of humans.