The present invention provides an oxide-base scintillator single crystal having an extremely large energy of light emission, adoptable to X-ray CT and radioactive ray transmission inspection apparatus, and more specifically to provide a Pr-containing, garnet-type oxide single crystal, a Pr-containing perovskite-type oxide single crystal, and a Pr-containing silicate oxide single crystal allowing detection therefrom light emission supposedly ascribable to 5d-4f transition of Pr.

The present disclosure discloses a method for growing a crystal with a short decay time. According to the method, a new single crystal furnace and a temperature field device are adapted and a process, a ration of reactants, and growth parameters are adjusted and/or optimized, accordingly, a crystal with a short decay time, a high luminous intensity, and a high luminous efficiency can be grown without a co-doping operation.

Awarm-color complex phosphor includes: a Ce.sup.3+-activated orange phosphor that has an excitation peak within a blue wavelength range of 440 nm or more and less than 480 nm and has a fluorescence peak within an orange wavelength range of 580 nm or more and less than 610 nm; and a Ce.sup.3+-activated red phosphor that has an excitation peak within a green wavelength range of 500 nm or more and less than 550 nm and has a fluorescence peak within a red wavelength range of 610 nm or more and less than 660 nm. Preferably, the Ce.sup.3+-activated red phosphor is a nitride-based compound.

The application relates to fluorescent powder which has a garnet structure and can be effectively excited by ultraviolet light or blue light, a method for preparing the fluorescent powder, and a light emitting device, an image display device and an illumination device comprising the fluorescent powder. A chemical formula of the fluorescent powder is expressed as: (M.sup.1a-xM.sup.2x)ZrbM.sup.3cOd, where M.sup.1 is one or two elements selected from Sr, Ca, La, Y, Lu and Gd, Ca or Sr being necessary; M.sup.2 is one or two elements selected from Ce, Pr, Sm, Eu, Tb and Dy, Ce being necessary; M.sup.3 is at least one element selected from Ga, Si, and Ge, Ga being necessary; and 2.8≦a≦3.2, 1.9≦b≦2.1, 2.8≦c≦3.2, 11.8≦d≦12.2, and 0.002≦x≦0.6.

A crystal material represented by a general formula (1):
(Gd.sub.1-x-y-zLa.sub.xME.sub.yRE.sub.z).sub.2MM.sub.2O.sub.7   (1),
where ME is at least one selected from Y, Yb, Sc, and Lu; RE is Ce or Pr; MM is at least one selected from Si and Ge; and ranges of x, y, and z are represented by the following (i): (i) 0.0≦x+y+z<1.0, 0.05≦x+z<1.0, 0.0≦y<1.0, and 0.0001≦z<0.05 (where, when RE is Ce, y=0 is an exception).

A curable composition, for production of coatings with an antimicrobial property, contains at least one film-forming polymer, at least one up-conversion phosphor, optionally at least one additive, and optionally at least one curing agent. The phosphor is selected from the idealized general formula (1), Lu.sub.3-a-b-nLn.sub.b(Mg.sub.1-zCa.sub.z).sub.aLi.sub.n(Al.sub.1-u-vGa.sub.uSc.sub.v).sub.5-a-2n(Si.sub.1-d-eZr.sub.dHf.sub.e).sub.a+2nO.sub.12, where a=0-1, 1≥b>0, d=0-1, e=0-1, n=0-1, z=0-1, u=0-1, v=0-1; with u+v≤1 and d+e≤1; Ln=praseodymium (Pr), gadolinium (Gd), erbium (Er), neodymium (Nd), or yttrium (Y); Lu=lutetium; and Li=lithium.

A dimmable light source for emitting white overall radiation may include a dimmer and a light-emitting diode. The dimmer may vary a current intensity of a current for operating the light-emitting diode during the operation of the light source. The LED may include a semiconductor layer sequence to emit primary radiation, and the LED may further include a conversion element configured to at least partially convert the primary radiation into secondary radiation having a first emission band with a first emission maximum ranging from 400 nm to 500 nm and a second emission band with a second emission maximum ranging from 510 nm to 700 nm. A relative intensity of the first emission band may reduce with decreasing current intensity of the current for operating the LED, and a relative intensity of the second emission band may increase with decreasing current intensity of the current for operating the LED.

A process can be used for the preparation of an up-conversion phosphor of the general formula (I):

A.sub.1-x-y-zB*.sub.yB.sub.2SiO.sub.4:Ln.sup.1.sub.x,Ln.sup.2.sub.z,   (I).

The process involves preparing a mixture, introducing the mixture into a reaction chamber of a thermal apparatus, heating the mixture until a thermal treatment temperature is reached with a heating ramp, thermally treating the heated mixture for a holding time of at least 0.02 h, cooling the thermally treated material to room temperature while maintaining a cooling ramp, and obtaining a silicate-based lanthanoid ion-doped phosphor according to formula (I).

A process can be used for the preparation of an up-conversion phosphor of the general formula (I)

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The process involves providing i) at least one lanthanoid salt, ii) a silicate or a silicon dioxide, iii) at least one alkaline earth metal salt and at least one alkali metal salt, and iv) at least one flux. The process then involves either mixing components i), ii), iii) and iv) by grinding to obtain a mixture; or mixing components i), ii), iii) and iv) in an organic polar or nonpolar solvent that is not a protic solvent by grinding to obtain a mixture, and precalcining the mixture. The process further involves calcining the mixture, and obtaining a silicate-based up-conversion phosphor of the general formula (I), preferably after cooling the material. At least 3.5% by weight of flux is used, based on the total amount of the reactants.

The invention relates to an inorganic scintillator material of formula Lu.sub.(2−y)Y.sub.(y−z−x)Ce.sub.xM.sub.zSi.sub.(1−v)M′.sub.vO.sub.5, in which: M represents a divalent alkaline earth metal and M′ represents a trivalent metal, (z+v) being greater than or equal to 0.0001 and less than or equal to 0.2; z being greater than or equal to 0 and less than or equal to 0.2; v being greater than or equal to 0 and less than or equal to 0.2; x being greater than or equal to 0.0001 and less than 0.1; and y ranging from (x+z) to 1.

In particular, this material may equip scintillation detectors for applications in industry, for the medical field (scanners) and/or for detection in oil drilling. The presence of Ca in the crystal reduces the afterglow, while stopping power for high-energy radiation remains high.