JPS6014059B2 - fluorescent surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phosphor screen that is covered with a phosphor that emits red light when exposed to ultraviolet light, and more particularly to a phosphor screen that has been improved to achieve high luminous efficiency at high temperatures.

Europium-activated yttrium vanadate or europium-activated yttrium vanadate phosphate is widely used as a phosphor for improving color rendering in the phosphor screens of high-pressure mercury lamps for lighting. This type of phosphor emits red light whose maximum intensity in the ultraviolet emission spectrum is at 61 orbitals.
In particular, the europium-activated yttrium phosphovanadate phosphor maintains its luminescence intensity even under high-temperature conditions.
It has the characteristic of emitting monochromatic red light. For this reason, it is used in phosphor screens as a phosphor to improve color rendering in high-pressure mercury lamps, where the temperature of the area coated with phosphor reaches a high temperature of 200 to 40 pm due to the heat from the mercury arc tube. ing. However, these phosphors are sensitive to manufacturing conditions, such as atmosphere, mixing conditions of raw materials, cleaning conditions for the phosphor, etc., making it difficult to obtain a homogeneous phosphor.

Then, it forms stoichiometric vanadate (), which inevitably causes the body color to turn yellow. This tendency is remarkable in europium-activated yttrium phosphovanadate phosphors, and when used as a phosphor for improving color rendering in a phosphor film for a high-pressure mercury lamp, it absorbs the visible light of the blue component of the mercury spectrum line and obtains luminous intensity. prevent it from happening. On the other hand, europium-activated yttrium vanadate phosphors do not have good temperature characteristics, and in high-pressure mercury lamps, the outer bulb overflows to around 300° C. during operation, so this drawback takes advantage of this and reduces the luminous intensity. The present invention provides a phosphor screen using an improved red-emitting phosphor in place of the phosphor of yttrium vanadate with eurobium or yttrium sinophosphate vanadate with europium.

That is, this invention has the general formula (Ln, -x-YEuxDyY)
V04, Ln contains at least one of Y, W, and 0.005SXSO. 2, 0<YSO.
The phosphor screen comprises a europium dysprosium co-activated rare vanadate red-emitting phosphor in the range of 0.005. The phosphor screen of this invention has a white body color as a red-emitting phosphor, has a better spectral reflectance than a phosphovanadate-based ant phosphor, and has a temperature dependence that is lower than that of a conventional vanadate-based phosphor. We use a material that is superior to the human body and emits light efficiently not only when excited by 2537A ultraviolet rays but also by 3650A excitation.

The characteristics of the red light-emitting phosphor according to the present invention were obtained by adding a certain amount of dysprosium Dy as a co-additive to the europium-activated rare vanadate phosphor.

Since this phosphor contains dysprosium Dy, it has better temperature dependence and spectral reflectance than a europium-activated rare earth vanadate-based saddle phosphor that does not contain dysprosium Dy. - Compared to a vanadate phosphor, the body color is white and there is no yellowing, and it can be easily obtained as an excellent phosphor that is stable in the manufacturing process. Figure 1 shows the temperature dependence of each phosphor used in each phosphor screen when a high-pressure mercury lamp is used as the irradiation source.

The horizontal axis represents the temperature in °C, the vertical axis represents the relative energy efficiency in arbitrary units, and the solid line 1 represents the temperature used in the phosphor screen of this invention.
．． 9549V04/Euo. o45Dyo. oo phosphor, dotted line 2 is europium-activated yttrium vanadate Y ship $V04/E scold. Q5 saddle photon, dashed line 3 indicates europium-activated yttrium phosphovanadate Y cape neck (Po.
5ooVo. 5oo) 04/E scolding. Regarding Q5 phosphor.
It can be seen from FIG. 1 that the phosphor used in the phosphor screen of the example has better temperature dependence than the phosphor shown by dotted line 2. Figure 2 shows the spectral reflectance of the phosphor measured to evaluate body color.

The axis represents the wavelength n kite, the vertical axis represents the spectral reflectance in arbitrary units, and the solid line 1, dotted line 2, and dashed-dotted line 3 all similarly correspond to the phosphors used in the various phosphor screens in Fig. 1. There is.
The phosphor used in the example phosphor screen shown by the solid line 1 has a significantly better spectral reflectance than the phosphor used in the comparative example phosphor screen shown by the dashed-dotted line 3, and exhibits a white color due to no absorption. known. In this invention, the phosphor is produced by weighing and collecting raw material salts that are easily oxidized by heating, which are either oxides of each constituent element, mixed in a ball mill or the like, and then packed into a container such as a quartz vortex or an alumina vortex. 800-1 in electric furnace
What is necessary is just to heat in the temperature range of 350:00 for 0.5 to 6.0 hours.

Furthermore, by repeating heating and baking, the luminescence intensity can be further improved. For the phosphor screen, the weight of butyl acetate solution 1 in which 1.5% by weight of nitrocellulose was dissolved was added to the weight of the host phosphor 1.
Shake the candle and make a coating suspension. This suspension is applied to the inner surface of the outer bulb of the high-pressure mercury lamp. A 400-watt fluorescent high-pressure mercury lamp was manufactured using a known conventional high-pressure mercury lamp assembly method.
In this invention, the concentration of dysprosium in the phosphor is determined according to the general formula 0<YSO. 005. This amount of dysprosium acts as a sensitizing agent for europium and does not contribute to luminescence. The excitation energy is therefore utilized more efficiently than with europium alone. Therefore, it is completely different from the method disclosed in Samurai Publication No. 45-2296, for example, in which dysprosium is added at a high concentration for the purpose of shifting the emission of europium and the emission of dysprosium. In this publication example, dysprosium is 5800
The light emission near A contributes. However, this emission is on the shorter wavelength side than the emission of europium near 6190A, so
This is not enough to sufficiently improve color rendering. Furthermore, in this case, since the excitation energy is dispersed for the emission of both europium and dysprosium, it is difficult to efficiently extract the emission from either of them. For example, vanadate phosphors activated only with europium or activated only with dysprosium have poor temperature characteristics.

Furthermore, a vanadate phosphor in which dysprosium is added at a high concentration to europium also does not improve the temperature characteristics. However, the amount of dysprosium in the phosphor defined in this invention acts as a sensitizer for europium and improves the temperature characteristics. In the prescribed general formula (Ln, -x-YE-DyY)VQ of the phosphor, the emission intensity increases when the europium concentration X is within the range of 0.005 to 0.2.

Outside this range, the emission intensity will be significantly reduced. The optimal range is between 0.015 and 0.070. When the dysprosium concentration Y is 0.005 or less, it exhibits a remarkable sensitizing effect on europium and improves the temperature characteristics. 0.0
If it exceeds 05, the concentration will be too high and the temperature characteristics will deteriorate.

The preferred range is from 0.001 to 0.000005, and within this range a significant sensitizing effect is exhibited. Examples of phosphor screens of this invention will be described below.

Yttrium oxide Y2Q149.3# to 150.1 and europium oxide EQII. 02 Yu and Dysprosium Oxide D Average 031.2 Salmon to 0.0012 Madara 7
A mixed nitric acid solution of yttrium, europium and dysprosium dissolved in 320 cc of 0% concentrated nitric acid and diluted with water was mixed with 620 cc of dimethyl oxalate, heated to about 80°C. Since yttrium, europium, and dysprosium hakamate co-separate at this temperature, the precipitate is kept at this temperature at a temperature of about 0. Worship the insects for hours and leave them alone. The precipitate is then washed with pure water and dried. 1000 to 1 dried oxalate
It is heated at 100° C. for about 1 to 2 hours to form an oxide. This oxide was thoroughly mixed with 137.92 ml of vanadine pentoxide V2Q in a ball mill, and then heated to 1200 ml in the atmosphere in an electric furnace.
Bake for an hour. ), use a fluxing agent such as Na2C03, K2C
03, CaC03, C03, MgC. 3・SteC.

3・NaF, KF, GdF3・YF3・KuF3, Japan 3B
03, Li Crab 407, KO7, etc. may be used for N.

Grind the scales thoroughly, wash with pure water, and over-dry in an oven. The emission brightness and reflectance under ultraviolet excitation of 2537A or 3650A for the europium dysprosium coactivated rare earth vanadate phosphors formed in this way and having different dysprosium contents, and for these phosphors. The luminous efficiency at the initial stage or after 100 hours is displayed for the light surface of the high-pressure mercury lamp. Items 8 and 9 in the table relate to the comparative europium-activated yttrium vanadate phosphor or the europium-attached yttrium vanadate phosphor. table

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the temperature dependence of the phosphors used in the fluorescent screens of Examples and Comparative Examples, and FIG. 2 is a spectral reflectance diagram of the saddle phosphor. Figure 1 Figure 2

Claims (1)

[Claims] 1 General formula (Ln_1_-_X_-_YEu_XDy_
Y) VO_4, Ln contains at least one of Y, Gd, and La, and 0.005≦X≦0.2, 0
A phosphor screen comprising a europium dysprosium co-activated rare earth vanadate red-emitting phosphor in the range <Y≦0.005.