JPH0662944B2 - Method for producing manganese-activated zinc silicate phosphor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a manganese-activated zinc silicate phosphor for a fluorescent lamp.

[Prior Art and Its Problems] It is generally known that when a manganese-activated zinc silicate phosphor is used for a fluorescent lamp, it emits a very bright radiation of 125 lumens per watt. Despite the extremely low manufacturing cost of zinc silicate phosphors, they are practically rarely used in fluorescent lamps. This is because in the manganese-activated zinc silicate phosphor, the deterioration of the luminous flux in the fluorescent lamp is extremely remarkable.

Therefore, a proposal has been made to improve the deterioration of the luminous flux of the manganese-activated zinc silicate phosphor when the fluorescent lamp is turned on. For example, in the proceedings of the 196th Symposium on Fluoroscopic Society,
It has been proposed to coat the particle surfaces of manganese-activated zinc silicate phosphors with silica gel or magnesium sulfide.

However, in spite of the above-mentioned proposal, conventionally, it is not possible to eliminate the luminous flux deterioration of the manganese-activated zinc silicate phosphor at the time of lighting the fluorescent lamp, and the phosphor for the white fluorescent lamp, for example, halophosphoric acid. A green component of a calcium fluorescent material or a three-wavelength type fluorescent lamp, for example, a manganese-activated zinc silicate fluorescent material is used as a fluorescent lamp fluorescent material in place of a cerium- and terbium-activated lanthanum phosphate fluorescent material. It didn't reach.

[Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances.
The purpose of the invention is to provide a method for producing a manganese-activated zinc silicate phosphor capable of industrially producing a manganese-activated zinc silicate phosphor with extremely little deterioration of luminous flux during lighting of a fluorescent lamp. is there.

SUMMARY OF THE INVENTION The present inventors have found that the composition of manganese-activated zinc silicate phosphor is 2
(ZnO) .SiO ₂ : Mn, which is a silicic acid (SiO ₂ · nH ₂ O) component having a strong adsorptive power because a part of silicon dioxide (SiO ₂ ) in the composition reacts with water during washing with water. When the fluorescent lamp is turned on, the silicic acid component adsorbs mercury (Hg), etc. of the fluorescent lamp by changing to
Considering that the luminous flux of the fluorescent lamp is deteriorated, a manganese-activated zinc silicate phosphor having extremely little luminous flux deterioration at the time of lighting of the fluorescent lamp is obtained by an industrially simple method by the following method. I have newly found that I can do it.

That is, the method of the present invention obtains phosphor particles by introducing manganese into a phosphor matrix of zinc silicate by firing, and first, a small amount of an organic polymer composed of polyvinyl alcohol is attached to the surface of the phosphor particles. Then, an inert gas and phosphor particles are sprayed in a reducing atmosphere in the temperature range of 1000 ° C. to 1300 ° C., and the phosphor particles are passed through the reducing atmosphere for a few seconds so that the surface of the phosphor particles is covered. It is characterized by processing.

[Operation] Fluorescent particles together with an inert gas at 1000 ° C to 1300 ° C
By spraying in a reducing atmosphere in the temperature range of 1, a layer of silicon nitride compound instead of silicon dioxide is uniformly formed on the surface of the phosphor. This improves the deterioration characteristics when the lamp is applied.

[Examples] Hereinafter, examples of the present invention will be described.

Example 1 First, prior to the description of Example 1 of the present invention, a method of manufacturing the manganese-activated zinc silicate phosphor used in the examples of the present invention will be described.

Zinc oxide, silicon dioxide and manganese fluoride were weighed as the phosphor raw materials, and these phosphor raw materials were sufficiently pulverized and mixed in a ball mill, filled in an alumina crucible, and fired in air at 1300 ° C. for 2 hours. The amount of manganese in the obtained manganese-activated zinc silicate phosphor was about 0.05 with respect to 1 mol of the zinc silicate matrix.
It has been reacted in moles.

Next, 0.1% by weight of polyvinyl alcohol as an organic polymer was added to the surface and dried, and 2 kg of this manganese-activated zinc silicate phosphor (average particle size 16 μm) was used for spray firing. N ₂ as an inert gas was delivered at a rate of 10 to 201 / min into an alumina pipe having a diameter of 1 cm. The inside of the alumina pipe was heated to 1200 ° C. by a heating means, the length of the pipe was 2 meters, and the treatment time of the fluorescent substance in the pipe was 3 seconds.

The thus obtained phosphor of the present invention and the conventional phosphor after baking, which had been washed with water, sieved and dried, were each treated with a 1% nitrocellulose butyl acetate solution (binder) to have a diameter of 27 cm. Thickness of 10 to 20 μm in a straight glass tube at a rate of 5 g
Was applied to prepare a lamp, and a luminous flux deterioration test was performed.

As a result, in the conventional fluorescent material, 100
The deterioration characteristic after the passage of time was 86.1% (broken line a in the drawing), whereas in the phosphor of the present invention, the deterioration characteristic after 100 hours has passed with respect to the initial luminous flux is 92.1% (in the drawing). The solid line 1) indicates that the luminous flux deterioration characteristic is improved by 6.0%.

(Example 2) A prototype was made in the same manner as in Example 1 except that the temperature of the pipe was maintained at 1000 ° C and the phosphor was allowed to pass through the pipe in 5 seconds, and the same luminous flux deterioration test was performed. It was

As a result, in the conventional fluorescent material, 100
The deterioration characteristic after the passage of time was 86.1% (broken line a in the drawing), whereas in the phosphor of the present invention, the deterioration characteristic after 100 hours has passed with respect to the initial luminous flux is 91.1% (in the drawing). The solid line 2) indicates that the luminous flux deterioration characteristic is improved by 5.0%.

[Effects of the Invention] According to the method of the present invention, a manganese-activated zinc silicate fluorescent material having improved luminous flux deterioration at the time of lighting a fluorescent lamp, which could not be improved by the conventional coating method, by a simple fluorescent substance spraying step. A light body is obtained.

Further, according to the method of the present invention, an industrially inexpensive phosphor can be obtained as a green component of a three-wavelength fluorescent lamp.

[Brief description of drawings]

The drawings are graphs showing the decrease in light output with time in a fluorescent lamp using the phosphor of the present invention.

Claims (1)

[Claims] 1. Manganese is introduced into a zinc silicate phosphor matrix by firing to obtain phosphor particles. First, a small amount of an organic polymer composed of polyvinyl alcohol is attached to the surface of the phosphor particles, and then, Spraying an inert gas and phosphor particles into a reducing atmosphere in the temperature range of 1000 ° C to 1300 ° C, and allowing the phosphor particles to pass through the reducing atmosphere for several seconds to treat the surface of the phosphor particles. A method for producing a manganese-activated zinc silicate phosphor, which comprises: