NOVELTY - A silicate-based phosphor comprises a complex oxide of calcium, strontium and/or barium, silicon, and scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, bismuth, lead and/or manganese.    USE - Silicate-based phosphor is used as conversion phosphor for conversion of all or some of blue or near-UV emission from luminescent diodes in illumination units of backlighting systems fitted in LCDs (especially of in-plane switching mode and twisted nematic mode), in electronic or electrooptical devices, and as wavelength conversion material for solar cells (all claimed). The electronic or electrooptical devices include organic FET, thin-film transistor, organic laser diode, organic integrated circuit, radio frequency identification tag, photodetector, sensor, logic circuit, memory element, capacitor, charge injection layer, Schottky diode, planarizing layer, antistatic film, conducting substrate or pattern, photoconductor, electrophotographic element, and organic light-emitting transistor.    ADVANTAGE - The silicate-based phosphor has increased purity and homogeneity, and can be prepared with easy temperature control, yield improvement, shape regulation, and safety.    DETAILED DESCRIPTION - A silicate-based phosphor comprises a complex oxide of calcium, strontium and/or barium, silicon, and scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, bismuth, lead and/or manganese of formula: (Ax,B'y,M1-x-y)SiO3.(SiO2)n.    M=cation chosen from Ca, Sr and Ba;    A,B'=Sc3+, Y3+, La3+, Ce3+, Pr3+, Nd3+, Pm3+, Sm3+, Sm3+, Eu3+, Gd3+, Tb3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+, Bi3+, Pb2+, Mn2+, Yb2+, Sm2+, Eu2+, Dy2+ and/or Ho2+;    n=greater than 0 and 10 or less;and    x,y=greater than 0 and 0.3 or less.    INDEPENDENT CLAIMS are included for the following:    (1) preparation of silicate-base phosphor, which involves mixing a silicon-containing agent and a salt containing elements M, A and B' in preset molar ratio in a solvent, adding a precipitation agent, primarily heat-treating the mixture at 900-1300 degrees C under oxidative atmosphere, and secondarily heat-treating the mixture at 900-1300 degrees C under reductive atmosphere; and    (2) illumination unit having light source(s) whose emission maximum is 250-530 nm, preferably 350-460 nm. All or some of the radiation is converted into longer-wavelength radiation by the silicate-based phosphor.