CS236389B1 - Luminiscent material emitting red light - Google Patents

Abstract

The invention relates to a luminescent substance defined by the composition* (γι_χ·Εϋχ)2θ5· .y SiOg, where x = 0.01 to 0.30 and ý and 1 to 6. The above-mentioned luminophore emits red light with a maximum between 610 and 620 nm and is intended in particular for low-pressure and high-pressure mercury light discharge sources and television screens. The invention solves the problem of replacing the red-emitting luminophore based on yttrium oxide activated by europium (Ϊ2Ο5 with Bu5+) and other yttrium compounds activated by europium with a luminescent substance in which the light and lifetime parameters Ý2°5 » Eu3+ and other physicochemical properties important from the point of view of use would be preserved when the yttrium and europium content is reduced. The invention can be applied in particular in lighting and communication technology. It can be used as a red component of "three-band" phosphors for low-pressure mercury-vapor discharge lamps and television screens, and as a color corrector for high-pressure mercury-vapor discharge lamps.

Description

The invention relates to a luminescent substance defined by the composition: (Υ _1<βχ · ^Βα χ)2θ3 · ^S ^° ₂ ' ^{where x} “ θ'θΐ ^to °> ³ ° and ay * 1 to 6. The above-mentioned luminophore emits red light with a maximum between 610 and 620 nm and is intended in particular for low-pressure and high-pressure mercury light discharge sources and television screens.

Currently, a number of inorganic luminescent substances emitting red light are known. Of these, yttria compounds activated by Eu ³⁺ are of particular technical importance.

A classic representative of these compounds is europium-activated yttrium oxide (YgOj : Eu ³⁺ ). Its advantage is a wide range of applications, the disadvantage is the high content of yttrium and europium, and thus the unfavorable price.

Therefore, phosphors with similar optical and other physicochemical properties important from the point of view of use as Y ₂ 0^ ^{: Eu} ^ ⁺ » ^al ® ⁸ have been developed, but with a lower content of yttrium and europium.

An example is a series of luminophores based on yttrium salts activated with Eu ³⁺ , e.g. YVO Eu ³⁺ .

some of which have also found technical applications, such as Eu ³⁺ , YP04 : Eu ³⁺ , ϊ(νι-χΡ _χ 0 ₄ ) : Eu ³⁺ and Y ₂ (O ₂ S) :

These substances have comparable luminous parameters β ΐ ₂ °3 with reduced yttrium and europium content ^{: but} due to changes in some physicochemical properties, their application possibilities are narrower. This fact concerns in particular their insufficient lifetime in low-pressure mercury discharge sources, where the most common red component of modern three-band phosphors is still yttrium oxide activated by Eu ³⁺ .

The above disadvantages are eliminated by the luminescent* substance we have designed with the above-defined composition. This phosphor has comparable light parameters and lifetime4 with a reduced content of yttrium and europium.

238 noet β Y ₂ 0^ : &P ⁺ and, in terms of the requirements for the expected applications, suitable physical and chemical properties. Therefore, it is able to replace the above-mentioned phosphors at lower production costs, which is especially important in the case of replacing YgO^ ^{: Bu} '^ ⁺ * in low-pressure mercury light discharge sources.

The following examples show the preparation of the proposed phosphor by dry and wet methods.

Example 1

A mixture of 0.95 mol _{of Y2} , 5 mol of FeO-2 and 1 mol of _SiO2 is homogenized for 1 hour in a vibrating mill. After homogenization, the mixture is annealed for 3 hours at a temperature of 120°C. The obtained product is homogenized again for 1 hour in a vibrating mill and annealed for 1 hour at a temperature of 130°C.

Example 2

Pour 0.2 mol of SiO ₂ into a mixture of 0.95 1 0.1 M solution of Y(NO^)j and 0.05 1 0.1 Jí solution of Eu(NO^)-^ and add 0.2 1 1 M solution of oxalic acid with constant intensive stirring. The obtained precipitate is filtered, washed 3 times with 0.2 1 0.1_ll solution of oxalic acid and 3 times with 0.2 1 acetone. The dried precipitate is calcined for 3 hours at a temperature of 1250^0.

Example 3

Pour 0.3 mol of SiCl^ into 3 l of 0.4 M NH^OH solution with constant intensive stirring. After the hydrolysis of SiCl^ has taken place, add 0.95 l of Y(N0^)j solution and 0.05 l of 0.1 J of Eu(NO^)^ solution. Pour in 0.2 l of phosphoric acid solution with constant stirring. The obtained precipitate is treated in the same way as in Example 2.

Claims (1)

SUBJECT OF THE INVENTION A luminescent substance emitting Red Light with a maximum of 610 - 620 nm with a composition ( ^Y lx * ^{E | i} x ^ 2 ⁰ 3 ' ^{y SiO} 2 » ^{where x} " ° » ^{01 to} °» 3 ° ^and y ^s 1 236 389 between up to 6.