JPH0826309B2 - Fluorescent body - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a divalent europium-activated alkaline earth metal magnesium silicate phosphor, and more particularly to a three-wavelength band emission type lamp and an enhanced lamp. It relates to a blue light emitting phosphor or a blue green light emitting phosphor used for a color rendering lamp.

[Prior Art and its Problems] In recent years, there has been an increasing demand for low-pressure mercury vapor discharge lamps, especially three-wavelength band emission type lamps. ,
The appearance of a fluorescent substance that emits light with high brightness when excited by ultraviolet rays is desired.

Hitherto, silicate phosphors have been attracting attention as low-priced blue light-emitting phosphors, but they have not been put into practical use in terms of light emission brightness and color tone. That is, regarding the silicate phosphors activated with divalent europium, the emission characteristics for many compositions have been investigated, and as a typical one of them,
As shown in Japanese Examined Patent Publication No. 48-37714, 2 (CaX, BaY, SrZ, E
uP) O ・ 1MgO ・ 2SiO ₂ (however, x + y + z + p = 1,0.003 ≦
A phosphor having a composition formula of p ≦ 0.05) is disclosed in Japanese Patent Publication No. Sho 48-37715, and is 3 (CaX / BaY / SrZ / EuP) O / 1MgO / 2SiO.
₂ (provided that x + y + z + p = 1,0.003 ≦ p ≦ 0.05) is a fluorescent substance, which is disclosed in Japanese Examined Patent Publication No. Sho 48-37716, and is BaX Sr.
Y EuP Si ₂ O ₅ (however, x + y + p = 1,0 ≦ y ≦ 0.40,0.005 ≦
Examples include fluorescent substances having a composition formula of p ≦ 0.10).

However, among these, the emission peaks of the phosphors of the three-component mixed system of alkaline earth metal oxide, magnesium oxide and silicic acid, which are disclosed in JP-B-48-37714 and JP-B-48-37715. Although it has a wide range from blue to blue-green, the emission brightness by ultraviolet excitation has not reached a practical level.

In addition, the barium silicate-based phosphor disclosed in Japanese Patent Publication No. 48-37716 has the highest emission brightness among conventionally known divalent europium-activated silicate phosphors. Despite showing, emission peak wavelength is 495nm to 505nm
Therefore, it has a drawback that it is not used as a blue-green component for a three-wavelength band emission type lamp that requires an emission peak wavelength around 480 nm.

Further, also in a high color rendering lamp with improved color rendering such as a white lamp, the appearance of a fluorescent substance having high brightness and emitting light of blue to blue-green is desired.

Therefore, the present invention has been made in view of such circumstances, and its purpose is to be mainly used in a three-wavelength band emission type lamp or a high color rendering lamp, the emission peak at around 480 nm at high brightness. The present invention provides an alkaline earth metal magnesium silicate phosphor that emits blue to blue green light.

[Means for Solving Problems] The inventors of the present invention firstly replace a part of barium of a barium silicate phosphor disclosed in Japanese Patent Publication No. 483771/1996 with magnesium to obtain high brightness. Emission peak at 480 nm
Based on the idea that it would be possible to obtain an ideal UV-excited blue light-emitting phosphor as the blue component of the three-wavelength fluorescent lamp, which is the front and rear, a silicate fluorescence activated by divalent europium. Various experiments on the body were repeated. As a result, the above-mentioned object is newly solved by the ultraviolet-excited blue-emitting phosphor of the following composition formula, that is, a divalent europium-activated alkaline earth metal magnesium silicate phosphor. I found it.

m (Bal-XYZ MX MgY EuZ O) .nSiO ₂ However, M represents at least one element of Sr and Ca, and m, n, x, y and z satisfy the following numerical values.

 0.30 ≦ m / n ≦ 0.95, 0 ≦ x ≦ 0.6, 0 <y ≦ 0.8, 0.001 ≦ z ≦ 0.15, x + y + z ≦ 0.8.

What has not been heretofore expected is that, in the barium silicate phosphor disclosed in Japanese Patent Publication No. 48-37716, an alkaline earth metal oxide (Ba containing europium as an activator)
O, SrO) and silicic acid (SiO ₂ ) have a stoichiometric ratio of 1: 2, when barium in the composition formula is partially replaced by magnesium, the alkali An ideal three-wavelength type with a dominant wavelength of around 480 nm and higher brightness than conventional barium silicate phosphors in a wide range of ratio (m / n) of earth metal oxide to silicate of 0.30 to 0.95. A blue to blue-green emitting phosphor for a fluorescent lamp was obtained.

That is, referring to FIG. 1, 1 in the above composition formula
The relationship between the relative emission luminance and the ratio of the coefficient m of the alkaline earth metal oxide to the coefficient n of silicic acid in m (Ba0.49 Mg0.49 Eu0.02) · nSiO ₂ as an example is shown. As is apparent from FIG. 1, when the ratio of the coefficients m and n, that is, when the molar ratio is smaller than 0.3 and when the molar ratio is larger than 0.95, the relative emission brightness is lower than that of the conventional barium silicate phosphor. The molar ratio is preferably in the range of 0.5 to 0.9.

Further, from the above composition formula, as is apparent, the present invention, as shown in JP-B-48-37716, may be substituted for part of barium by strontium, and further, part of barium. By substituting with calcium and / or strontium, it is possible to obtain a blue to blue-green light emitting phosphor for a three-wavelength type fluorescent lamp having higher brightness than ever before. When the number of substitution moles, that is, the coefficient x in the above composition formula exceeds 0.6 with respect to barium being 1, the emission luminance is significantly reduced, which is not practical. The coefficient x is preferably 0.4 or less.

The change in the emission peak wavelength mainly depends on the amount of magnesium substituting barium, and the emission peak wavelength shifts to a short wavelength as the amount of magnesium substituting barium increases. Then, as shown in FIG. 2, when the amount y of magnesium exceeds 0.8 with respect to the case where barium is 1, the emission luminance is remarkably lowered and becomes impractical. It is preferable that the range of the amount y of magnesium is 0.03 to 0.55. In FIG. 2, when m = 1, n = 2, x = 0 and z = 0.02 in the above composition formula, that is, the amount of magnesium y in Ba0.08-YMgY Eu0.02O.2SiO ₂ is y. And the relative emission brightness.

Further, as shown in FIG. 3, when the europium amount z in the above composition formula is 0.001 or less and when it is 0.15 or more, the emission luminance is lowered, which is not practical. Preferably, the europium amount z is selected between 0.01 and 0.07. Incidentally, in FIG. 3, in the above composition formula, m = 1, n
= 2, x = 0 and y = 0.5, that is, Ba0.5-ZMg
5 shows the relationship between the amount of europium z in 0.5 EuZ O.2SiO ₂ and the relative emission brightness.

Further, a feature of the phosphor according to the present invention is that it has an oxidation resistance equal to or higher than that of a conventional barium silicate phosphor.

[Examples] Prior to Examples, a method for manufacturing a phosphor according to the present invention will be described.

The phosphors of the present invention are generally synthesized by well known methods. That is, strontium oxide, magnesium oxide, barium oxide, calcium oxide, europium oxide, silicon dioxide, which are oxides of the elements that make up the composition of the phosphor, or these oxides are formed by decomposition etc. by the end of the firing step. The compounds are mixed uniformly. Next, the mixed raw material mixture is placed in a weak reducing atmosphere using an electric furnace or the like.
Bake at a temperature of 900 ° C to 1300 ° C for several hours.

In this firing step, ammonium halide, an alkaline earth metal halide or the like may be added to the raw material mixture in order to obtain high emission brightness. This allows
The formation reaction of the fluorescent matrix and the diffusion of the activator into the fluorescent matrix are promoted.

 Hereinafter, description will be made based on examples.

To (Example 1) Composition of the _{Ba0.7 Sr0.23 Mg0.05 Eu0.02 O · 2SiO 2} , was weighed following ingredients.

Barium oxide 107.3g Magnesium oxide 2.015g Strontium oxide 23.83g Europium oxide 3.519g Silicon dioxide 120.2g Ammonium fluoride 2.5g Pure water was added to these raw materials, and the mixture was mixed in a slurry state and dried. The dried raw material mixture was filled in a quartz crucible with a lid, and then baked in an electric furnace at 1180 ° C. for 3 hours in the air. After cooling, the fired product is crushed and passed through a 200 mesh sieve. The calcined product that passed through the sieve was calcined for 2 hours at 1100 ° C. in a nitrogen atmosphere mixed with 3% hydrogen using an electric furnace.

The obtained calcined product, that is, the phosphor of this example has an emission peak wavelength at 496 nm due to ultraviolet excitation (253.7 nm), and has a CI
At the E chromaticity point, it was a blue-green light emitting phosphor represented by x = 0.215, y = 0.373. The emission spectrum of this phosphor is shown by curve 1 in FIG. 4, and the emission spectrum of the conventional barium silicate phosphor is shown by curve A for comparison.

(Example 2) Since the composition is Ba0.78 Mg0.20 Eu0.02 O · 2SiO ₂ ,
The following raw materials were weighed.

Barium carbonate 153.9 g Magnesium oxide 8.06 g Europium oxide 3.519 g Silicon dioxide 120.2 g Barium fluoride 3.0 g Barium chloride 1.0 g Methanol was added to these raw materials, and the mixture was mixed in a slurry form and dried. Using an electric furnace, dry the raw material mixture,
It was fired at 1130 ° C. for 3 hours in a nitrogen atmosphere mixed with 3% hydrogen.

The obtained fired product, that is, the phosphor, was excited by ultraviolet rays (253.7n
m) and has an emission peak wavelength at 479 nm as shown by the curve 2 in FIG. 4, and is a blue-green emitting phosphor represented by x = 203, y = 0.297 at the CIE chromaticity point. Met.

Example 3 The following raw materials were weighed in order to make the composition 1.5 (Ba0.5 Mg0.485 Eu0.015 O) · 2SiO ₂ .

Barium carbonate 148.0g Magnesium oxide 29.33g Europium oxide 3.959g Silicon dioxide 120.2g Magnesium fluoride 1.60g Ammonium chloride 0.70g Pure water was added to these raw materials, and they were mixed in a slurry form and dried. After filling the dried raw material mixture into a quartz crucible with a lid, it was baked in an electric furnace at 1150 ° C. for 3 hours in the air. After cooling, the fired product was crushed and passed through a 200 mesh sieve. 3% of the fired product that has passed through a sieve using an electric furnace
The mixture was fired at 1100 ° C. for 2 hours in a nitrogen atmosphere containing hydrogen.

The obtained fired product, that is, the phosphor, was excited by ultraviolet rays (253.7n
m), as shown by curve 3 in FIG.
Has an emission peak wavelength at CIE color point x = 0.157,
It was a blue-emitting phosphor represented by y = 0.160.

Example 4 In order to make the composition Ba0.485 Mg0.485 Eu0.03 O · 2.8SiO ₂ , raw materials were weighed as follows.

Barium carbonate 95.71 g Magnesium oxide 19.55 g Europium oxide 5.279 g Silicon dioxide 168.3 g Magnesium fluoride 1.50 g Methanol was added to these raw materials, and the mixture was mixed in a slurry form and dried. 3% of dried raw material mixture using an electric furnace
Calcination was performed at 1180 ° C. for 3 hours in a nitrogen atmosphere mixed with hydrogen.

The obtained fired product, that is, the phosphor, was excited by ultraviolet rays (253.7n
m), as shown by the curve 4 in FIG. 4, the emission peak wavelength is 474 nm, and x = 0.
It was a blue-emitting phosphor represented by 190, y = 0.269.

[Effect of the Invention] As described above, according to the present invention, a divalent europium-activated alkaline earth metal magnesium silicate phosphor having extremely high brightness can be obtained as compared with the conventional barium silicate phosphor, Moreover, this alkaline earth metal magnesium silicate phosphor is used in a three-wavelength band emission type lamp and a high color rendering lamp, and is an extremely ideal blue light emission or blue green color with a high light emission peak of around 480 nm. It is a luminescent component.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the ratio (m / n) of the coefficient m of alkaline earth metal oxide and the coefficient n of silicic acid and the relative emission brightness of the phosphor in the composition of the phosphor of the present invention. FIG. 2 is a graph showing the relationship between the magnesium amount y and the relative light emission brightness in the phosphor of the present invention, and FIG. 3 is a graph showing the relationship between the europium amount z and the relative light emission brightness in the phosphor of the present invention. FIG. 4 is a graph showing the UV-excited emission spectrum of the phosphor according to the example of the present invention.

Claims (1)

[Claims] 1. A phosphor characterized by being a divalent europium-activated alkaline earth metal magnesium silicate phosphor represented by the following formula. m (Bal-XYZ MX MgY EuZ O) .nSiO2 However, M represents at least one element of Sr and Ca, and m, n, x, y and z satisfy the following numerical values. 0.30 ≦ m / n ≦ 0.95, 0 ≦ x ≦ 0.6, 0 <y ≦ 0.8, 0.001 ≦ z ≦ 0.15, x + y + z ≦ 0.8.