The present disclosure discloses a blue fluorescent powder for a three primary color warm white LED and a preparation method thereof. SrCO.sub.3, NH.sub.4Cl, H.sub.3BO.sub.3, Eu.sub.2O.sub.3, and NH.sub.4H.sub.2PO.sub.4 function as raw materials to obtain a chemical formula of a blue fluorescent powder Sr.sub.(2-x)Eu.sub.x(BO.sub.3).sub.y(PO.sub.4).sub.(1-y)Cl in a reducing atmosphere by a solid-state sintering method, wherein 0.001≤x≤0.1 and 0.001≤y≤0.5. The blue fluorescent powder is mixed with CaAlSiN.sub.3:Eu.sup.2+ red fluorescent powder and (SrBa).sub.2SiO.sub.4:Eu.sup.2+ green fluorescent powder at a certain proportion to emit warm white light with a light efficiency and a color rendering index under a violet light excitation. An application prospect is wide.

A phosphor according to an embodiment is a europium-activated alkaline-earth chloroapatite phosphor having a composition expressed by a composition formula: (M.sub.1-xEu.sub.x).sub.5(PO.sub.4).sub.3Cl, where M is an alkaline-earth element containing at least Sr and Ba, x is an atomic ratio satisfying 0.04≤x≤0.2. In the phosphor of this embodiment, absorptance of light at a wavelength of 400 nm is 90% or more, and absorptance of light at a wavelength of 650 nm is 2% or less.

The present invention improves the performance of an analyzer and facilitates the maintenance of the analyzer. This fluorescent body is produced by firing a raw material which contains: an alumina; and at least one among Fe, Cr, Bi, Tl, Ce, Tb, Eu, and Mn, wherein the raw material contains 6.1-15.9 wt % of sodium with respect to the total amount of the raw material.

A composite material includes at least one photoluminescent material embedded as a light source in a transparent matrix, wherein a refractive index (n.sub.P) of the at least one photoluminescent material and a refractive index (n.sub.M) of the matrix differ by at most ±0.2.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

A light emitting device includes a light emitting element having a peak emission wavelength of 410 nm to 440 nm and a phosphor member. The phosphor member includes a first phosphor having a peak emission wavelength of 430 nm to 500 nm and containing an alkaline-earth phosphate, a second phosphor having a peak emission wavelength of 440 nm to 550 nm and containing at least one of an alkaline-earth aluminate and a silicate containing Ca, Mg, and Cl, a third phosphor having a peak emission wavelength of 500 nm to 600 nm and containing a rare-earth aluminate, a fourth phosphor having a peak emission wavelength of 610 nm to 650 nm and containing a silicon nitride containing Al and at least one of Sr and Ca, and a fifth phosphor having a peak emission wavelength of 650 nm to 670 nm and containing a fluorogermanate.

To provide a semiconductor light emitting device which is capable of accomplishing a broad color reproducibility for an entire image without losing brightness of the entire image. A light source provided on a backlight for a color image display device has a semiconductor light emitting device comprising a solid light emitting device to emit light in a blue or deep blue region or in an ultraviolet region and phosphors, in combination. The phosphors comprise a green emitting phosphor and a red emitting phosphor. The green emitting phosphor and the red emitting phosphor are ones, of which the rate of change of the emission peak intensity at 100 C. to the emission intensity at 25 C., when the wavelength of the excitation light is 400 nm or 455 nm, is at most 40%.

An LED pump light with multiple phosphors is described. LEDs emitting radiation at violet and/or ultraviolet wavelengths are used to pump phosphor materials that emit other colors. The LEDs operating in different wavelength ranges are arranged to reduce light re-absorption and improve light output efficiency.

According to one embodiment, a white light source includes a combination of a light emitting diode and phosphors. One of the phosphors is at least a cerium activated yttrium aluminum garnet-based phosphor. There is no light emission spectrum peak at which a ratio of a largest maximum value to a minimum value is greater than 1.9. The largest maximum value is largest among at least one maximum value present in a wavelength range of 400 nm to 500 nm in a light emission spectrum of white light emitted from the white light source. The minimum value is adjacent to the largest maximum value in a longer wavelength side of the light emission spectrum.

An LED pump light with multiple phosphors is described. LEDs emitting radiation at violet and/or ultraviolet wavelengths are used to pump phosphor materials that emit other colors. The LEDs operating in different wavelength ranges are arranged to reduce light re-absorption and improve light output efficiency.