JPS584957B2 - discharge lamp - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a discharge lamp that emits light from near ultraviolet to blue light, and more specifically, a discharge lamp that uses a composite halide consisting of an alkaline earth metal fluoride, an alkaline earth metal halide, and a potassium halide as a matrix. Divalent europium (Eu2+
) and relates to a discharge lamp having a phosphor film made of a composite halide phosphor activated with phosphor.

Conventionally, Eu2+-activated double-activated logenide phosphors include:
The one disclosed in Japanese Patent Application Laid-Open No. 49-42582 is known.

This is because its composition formula is (Bat-X-Y-9, Srx,
Cay, Eup) F (Ce1-a-b, Bra, Ib
) (However, X, y, p, a and b are y≦0.20゜x+y
+p≦1. a+b≦1 and 0.001≦p≦0.20
Eu2+-activated alkaline earth metal fluoride halide phosphor expressed by It is a phosphor made of a halide and activated with Eu2+.

As described in JP-A No. 49-42582, this Eu2+-activated alkaline earth metal fluoride halide phosphor exhibits a high emission spectrum under ultraviolet excitation as shown in Figure 1. It emits light efficiently in the near-ultraviolet region and is useful as a phosphor for discharge lamps.

However, although this Eu2+-activated alkaline earth metal fluorohalide phosphor shows highly efficient near-ultraviolet emission under ultraviolet excitation, it hardly emits light in the visible region, and therefore cannot be used as a visible light source. It cannot be used as a phosphor film in discharge lamps, and the afterglow after excitation is stopped is very long.This afterglow property is a major drawback in the practical use of this phosphor in discharge lamps. It becomes.

Therefore, it is strongly desired to improve the luminescent properties of this Fu2+u2+ alkali earth metal fluorohalide phosphor.

The present invention exhibits near-ultraviolet to visible light emission with higher efficiency than the discharge lamp using the Fu2+u2+ alkali earth metal fluorohalide phosphor as a fluorescent film, and the Fu2+u2+ alkali earth metal fluorohalide phosphor The object of the present invention is to provide a discharge lamp having a fluorescent film made of a Fu2+u2+ halide phosphor, which has better afterglow characteristics than a discharge lamp having a fluorescent film made of a Fu2+u2+ halide phosphor.

The present inventors conducted various studies in order to achieve the above object, and as a result, the alkaline earth metal fluoride and alkaline earth metal which are the base constituents of the Fu2+u2+ alkali earth metal fluoride halide phosphor. A composite halide phosphor made of a composite halide prepared by solidly dissolving potassium halide in a halide and activated with Eu2+ can be produced using the conventional Eu2+ activated alkaline earth phosphor under ultraviolet excitation. It exhibits more efficient near-ultraviolet to blue light emission than metal fluorohalide phosphors, and the afterglow properties of the phosphors are significantly higher than those of Eu2+-activated alkaline earth metal fluorohalide phosphors. It has been found that this material has excellent properties and is useful as a phosphor for discharge lamps.

The discharge lamp of the present invention has a composition formula of MoF3. xMe'X2・yKX'zEu"+(However, M
e) Me' is at least one of the alkaline earth metals consisting of barium, strontium and calcium; x and x' are each at least one of chlorine and bromine; x, y and 2 are each 080 ≦X≦
1.50゜0, IO≦y≦1.50 and 0.001≦
2≦0.20) The above-mentioned method is characterized by having a phosphor film consisting of a Eu2+-activated double-activated fluoride phosphor represented by: 2≦0.20. More preferable X, y and binary ranges of the composition formula are 0.95≦X≦1.20, 0.95≦X≦1.20, respectively.
20≦y≦1.00 and 0.01≦2≦0.10.

R used in the discharge lamp of the present invention represented by the above compositional formula
The u2+-activated double-activated monogenide phosphor is manufactured by the manufacturing method described below.

First, the raw materials for the phosphor include 1) an alkaline earth metal fluoride whose chemical formula is MoF3 (where Me is at least one of alkaline earth metals consisting of barium, strontium, and calcium); 2) an alkaline earth metal fluoride whose chemical formula is MoF3; 'X2 (where Me' is at least one of the alkaline earth metals consisting of barium, strontium and calcium, and X is at least one of chlorine and bromine) , 3) Potassium halide represented by the chemical formula KX' (where X' is at least one of chlorine and bromine) and 4) Potassium halide whose chemical formula is EuX3'' (where X is a halogen consisting of chlorine, bromine and fluorine) europium halide represented by at least one of the following: europium oxide (B
a2O3) and nitrates, sulfates, etc. at high temperatures.
At least one of the europium compounds that can be changed to 20s is used.

The above four phosphor raw materials are stoichiometrically MoF3, XMe'X-yKX', zEu3+ (however, M
e, Me', X and X' have the same definitions as above, and
, y and 2 are respectively 0.80≦X≦1.50, 0.
(The number satisfies the following conditions: 10≦y≦1.50 and o, ooi≦2≦0.20) The mixture is weighed so as to have the following mixing composition formula, and thoroughly mixed using a ball mill, mixer mill, etc.

From the viewpoint of the luminous efficiency and afterglow characteristics of the resulting phosphor, the X, y, and Z values of the above mixed composition formula are more preferably within the range of 0.95≦X≦1.20, respectively. o, 2o<y<i,o
.

and 0.01<z<0010.

Of the phosphor raw materials, MoF3 and Me'X2 may be chemically precipitated as MoF3.Me'X2 when Me and Me' are the same alkaline earth metal.

That is, by adding an equivalent amount of an aqueous solution of alkali metal fluorides such as NaF or KF to an aqueous Me'X2 solution, Me'F2/Me'X2 is prepared.
chemically precipitated as

This reaction can be carried out using the following reaction formula % Formula % In addition to the above four phosphor raw materials, a fluxing agent such as ammonium halide (NH4C1tNH4BrtNH4F-HF), which is often used in the production of composite halide phosphors, may also be used. good.

Next, the phosphor raw material mixture is filled into a heat-resistant container and fired.

The firing is performed in a weakly reducing atmosphere such as a nitrogen atmosphere containing 2% hydrogen, for example, in order to convert Eu3+ to Eu2+.

Calcining in a strongly reducing atmosphere is not preferred because part of the base alkaline earth metal is liberated, giving the phosphor a gray-black or yellow-gray color and significantly reducing luminous efficiency.

A suitable firing temperature is 600°C to 1000°C.

More preferably it is 700°C to 800°C.

The firing time varies depending on the filling amount, firing temperature, etc., but within the above firing temperature range, 1 to 5 hours is appropriate.

It should be noted that once the phosphor raw material mixture has been fired under the above firing conditions to produce a phosphor, it can be re-fired once or twice or more under the same firing conditions as above to produce a good product with good luminous efficiency. Fluorescent material can be obtained.

After firing, a phosphor is obtained by performing various operations generally employed in the production of phosphors, such as washing, drying, and sieving.

Note that cleaning after firing is performed using an organic solvent such as acetone, ethyl acetate, butyl acetate, or ethyl alcohol.

This is because the matrix complex halide easily decomposes in hot water, and when washed with hot water as in normal phosphor manufacturing, M gradually begins to form on the crystal surface.
It decomposes into eF2, Me'X2 and KX'.

By the manufacturing method described above, the composition formula is MeF2.
XMe'X2・yKX':zEu2+ (However, Me,
(Me', X, X', x, y and 2 have the same definitions as above).

However, from a practical point of view, the Eu2+-activated double-activated logenide phosphor obtained by the above production method generally has a large average particle size and a wide particle size distribution, that is, the deviation value (logσ) of the particle size is large.

The large average particle size and wide particle size distribution not only have a negative effect on the coating properties of this phosphor when used as a fluorescent film for discharge lamps, but also have a negative effect on the density and adhesion of the resulting phosphor film. It becomes impersonal.

Moreover, a wide particle size distribution is not preferable because it lowers the yield when obtaining a phosphor having a specific particle size range through strict classification.

In order to obtain an Eu2+-activated doubly activated halogenide phosphor having an average particle size and particle size distribution suitable for practical use, the present inventors investigated various fluxes to be used when producing the phosphor. did.

As a result, it was found that when magnesium chloride (CM9C12) was used as a fluxing agent, a phosphor having an average particle size and particle size distribution suitable for practical use could be obtained.

Figure 2 shows BaF2・BaCl2・0,5KCl: 0-0
2 is a graph showing the relationship between the amount of MgCe2 (% by weight) used in the production of a 6Eu2+ phosphor and the average particle diameter (curve a) and deviation value (curve b) of the obtained phosphor.

The amount of M9C12 on the horizontal axis is the target BaF2/BaCe2
- 0.5KCd: 0.06Eu2+ It is shown in weight% with respect to the phosphor.

As is clear from Fig. 2, a practical phosphor can be obtained in terms of average particle size and particle size distribution when the amount of MgCl2 is 2.
This is the case when the amount is in the range of 20% by weight.

If the amount of M9C12 is less than 2% by weight, both the average particle diameter and the deviation value become large, which is not preferable.

Further, when the amount of MgCe2 is more than 20% by weight, the deviation value is not a problem, but the average particle diameter becomes too small, which is not preferable.

A more preferred range of MEC12 is 5% to 15% by weight.

M9C12 is removed by cleaning with an organic solvent after firing.

In addition, Figure 2 shows BaF2・BaC6・05KCd:0.0
This is a graph showing the relationship between the amount of M9C12 added and the average particle diameter and deviation value of the phosphor obtained for the 6Eu2+ phosphor, but it also shows the relationship between the amount of MgCl2 added and the average particle diameter and deviation value of the phosphor obtained for phosphors of other compositions. Regarding the relationship between the average particle diameter and the deviation value, results similar to those shown in FIG. 2 were obtained.

From the above results, one compositional formula is the Eu2+ activated complex represented by MeF2.xMe'X2.yKX':zEu2+ (Me, Me', X, X', x, y and 2 have the same definitions as above) M9CI2 is used as a fluxing agent to obtain a phosphor with a practical average particle size and particle distribution when producing an activated halogenide phosphor.
The amount is between 2 and 20% by weight of the desired phosphor of the above compositional formula.
% by weight, more preferably 5% to 15% by weight
It can be said that

The Eu2+-activated doubly activated logenide phosphor used in the discharge lamp of the present invention emits near-ultraviolet to blue light with high efficiency under ultraviolet excitation, and has excellent afterglow characteristics.

FIGS. 3 and 4 show Eu used in the discharge lamp of the present invention.
This figure illustrates the emission spectrum of a 2+-activated double-activated logenide phosphor when excited by ultraviolet light.

As is clear from FIGS. 3 and 4, the emission spectrum of the phosphor used in the discharge lamp of the present invention has an emission peak in the near ultraviolet region of 390 nm to 400 nm, and an emission peak of 420 nm.
It consists of two emission peaks, one in the blue region from 420 to 435 nm, and as shown in Figure 3, as the amount of KCd, which is the base component of the phosphor, increases, the emission peak in the blue region from 420 to 435 nm increases. The luminescence peak gradually becomes stronger.

In addition, Fig. 3 shows BaF2・BaCl2・yKcd: 0.0
This is the emission spectrum of the 6Eu2+ phosphor when excited by ultraviolet light at 253.7 nm, but in the case of phosphors with other compositions, the blue light from 4.20 nm to 435 nm also changes as the amount of KCl, which is a base component, increases. It was confirmed that the luminescence peak in the region gradually became stronger.

Table 1 below shows CaWO4 phosphor, JP-A-49-4258
Eu2+ activated alkaline earth metal fluorohalide phosphor disclosed in No. 2 and Eu2 used in the discharge lamp of the present invention.
This figure shows the luminance and afterglow characteristics of the +-activated double-activated logenide phosphor upon UV excitation.

Emission brightness is shown as a relative value with CaWO4 phosphor as 100, and fluorescence characteristics are shown as 1/10 decay time.

As is clear from Table 1, the Eu2+-activated double-activated halogenide phosphor used in the discharge lamp of the present invention is a CaWO4 phosphor and the conventionally known Eu2+-activated alkaline earth metal fluoride under ultraviolet excitation. It emits light with much higher brightness than halide phosphors.

The Eu2+-activated double-activated halide phosphor used in the discharge lamp of the present invention exhibits much higher luminance than the Eu2+-activated alkaline earth metal fluoride halide phosphor under ultraviolet excitation. The reason for this is that in this Eu2+-activated doubly activated logenide phosphor, MeF2 is used as a matrix component.
This is because by using KX' in addition to 2Me'X2, light emission in the blue region appears.

Furthermore, as is clear from Table 1, the Bu2+u2+ combined halide phosphor used in the discharge lamp of the present invention has a higher resistance to ultraviolet excitation than the conventionally known Eu2+ activated alkaline earth metal fluoride halide phosphor. Excellent afterglow properties.

In other words, the afterglow time is short.

This shows that this phosphor emits light with high efficiency under ultraviolet excitation, and also increases the practicality of this phosphor as a phosphor for discharge lamps.

A high-intensity blue light source can be obtained by using the above-mentioned Eu2+-activated double-activated nitogenide phosphor as a phosphor film of a discharge lamp.

As is clear from the emission brightness data of 253.7 m ultraviolet excitation in Table 1, the discharge lamp of the present invention having the above-mentioned Eu2+-activated double-activated nitride phosphor as a phosphor film has CaWO4
It has a luminance that is approximately 2.5 to 3 times as high as that of a discharge lamp that uses a phosphor as a phosphor film.

Moreover, the color purity of the blue color is superior to that of a discharge lamp using a CaWO4 phosphor as a phosphor film.

It should be noted that the conventionally known Eu2+-activated alkaline earth metal fluoride halide phosphors emit light when excited by ultraviolet light in the near-ultraviolet region, as shown in FIG. 1, and hardly emit light in the blue region. Although it has utility as a phosphor for near-ultraviolet radiation discharge lamps, it cannot be used as a phosphor film for discharge lamps intended as a blue light source like the above-mentioned Eu2+-activated double-activated fluoride phosphor. .

The structure of the discharge lamp of the present invention is exactly the same as that of the conventional discharge lamp except for the phosphor film made of the Eu'' activated composite halide phosphor described above.

As explained above, the discharge lamp of the present invention emits light with high brightness and also has excellent afterglow characteristics.As such, the industrial utility value of the present invention is extremely large.

Next, examples of the present invention will be shown.

Example 1 Strontium fluoride SrF2 125g Strontium chloride 5rC712.66H2O293 Potassium chloride KCI 74.59 Europium fluoride BaF3 12.5g 25g of MFIJ2 as a flux was further added to each of the above phosphor raw materials and thoroughly mixed using a ball mill.

The resulting mixture was filled into an alumina crucible and fired at a temperature of 700° C. for 3 hours in a nitrogen atmosphere containing 2% hydrogen.

After firing, the fired product was washed with acetone, dried, and then placed in a tube.

In this way, the average particle diameter was 6.0μ, and the deviation value was 0.4.
5, SrF2・], 15rC12・KCl: 0-0
A 6Eu2+ fluorophore was obtained.

This phosphor exhibited excellent luminescent properties as shown in Table 1 under ultraviolet excitation.

Further, when a discharge lamp was manufactured using this phosphor in a conventional manner, the light-emitting characteristics of the phosphor shown in Table 1 were maintained as they were in the discharge lamp obtained.

Example 2 269 g of barium chloride (BaC12.2H20) was added to 55 g of water.
A NaF solution prepared by dissolving 46 & of sodium fluoride (NaF) in 16 water was added to the resulting BaCl2 solution.

The resulting white precipitate (BaF2/BaC12) was filtered off, and 1
It was dried at 00°C.

Next, 19 g of potassium chloride (KCI) was dissolved in 50 ml of water, and europium chloride (FuC6) was added to the resulting KC6 solution.
3) 15.59 and the above BaF2”BaCl2192
g was added to form a paste, thoroughly mixed, and dried.

211 g of MgCl and NH4C6IIg were added as a flux to the phosphor raw material mixture thus obtained, and thoroughly mixed using a ball mill.

The resulting mixture was filled into an alumina crucible and fired at a temperature of 740° C. for 2 hours in a nitrogen atmosphere containing 2% hydrogen.

After firing, the fired product was washed with butyl acetate, dried, and placed in a tube.

In this way, the average particle diameter was 5.0μ, and the deviation value was 0.4.
BaF2-BaCl2-0.5KCl: 0.0
6 Eu2+u2+ was obtained.

This phosphor exhibited excellent luminescent properties as shown in Table 1 under ultraviolet excitation.

Further, when a discharge lamp was manufactured using this phosphor in a conventional manner, the excellent light emitting characteristics of the phosphor shown in Table 1 were maintained in the discharge lamp obtained.

[Brief explanation of the drawing]

FIG. 1 shows the emission spectrum of a conventionally known Eu2+ activated alkaline earth metal fluorohalide phosphor. Figure 2 shows Mg used as a flux when producing the Eu2+-activated double-activated hydrogenide phosphor used in the discharge lamp of the present invention.
It is a graph showing the relationship between the amount of C62 and the average particle diameter and deviation value of the particle diameter distribution of the obtained phosphor, and curve a is
The relationship between the amount of Cl2 and the average particle diameter, the curve shows the relationship between the amount of MgCl2 and the deviation value of the particle size distribution, and the horizontal axis shows the relationship between the amount of MgCl2 and the deviation value of the particle size distribution.
The amount of Cl2 is expressed in weight percent relative to the intended Eu2+-activated double-activated nitride phosphor. FIGS. 3 and 4 show Eu used in the discharge lamp of the present invention.
This is an emission spectrum of a 2+-activated double-activated genide phosphor at 253.7 m ultraviolet excitation.

Claims (1)

[Scope of Claims] 1 The compositional formula is MeF2.xMe'' is at least one of chlorine and bromine, x, y and 2 are each 0.80≦
X≦1.50゜0.10≦y≦1.50 and o, oo
A discharge lamp characterized in that it has a fluorescent film made of a divalent europium-activated composite halide phosphor represented by the following formula: i≦2≦0.20. 2 X, y and 2 in the above composition formula are each 0.95≦
X≦1.20, 0.20≦y≦1.00 and 0.01
The discharge lamp according to claim 1, wherein the number satisfies the condition ≦2≦0.10.