JP3268761B2 - High brightness and long afterglow aluminate phosphor with excellent heat and weather resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel aluminate phosphor having high luminance and long afterglow and having excellent heat and weather resistance. More specifically, the present invention provides:
It has excellent weather resistance and has high brightness and long life when excited by high-velocity particle energy such as electron beam, X-ray, ultraviolet ray or visible light, or a combination thereof in dark places such as indoors and outdoors, and even underwater. The present invention relates to an aluminate luminous body having light properties, in particular, dramatically improved luminance and afterglow.

[0002]

2. Description of the Related Art Phosphor refers to a substance that emits light when excited by some external stimulus such as particle energy, X-rays, and light. The luminous body having a long life is referred to as a “luminous body” here. Such luminous bodies are of interest from the viewpoint of energy saving and new energy, and are expected to be multi-colored and have high brightness with the diversification of displays and the enhancement of functions.

[0003] As an inorganic phosphorescent body, a luminous body of a sulfide and an oxide such as strontium aluminate has been reported. Examples of the sulfide-based phosphor include (Ca, Sr) S: Bi ³⁺ phosphor that emits blue light and Zn that emits yellow-green light.
S: Cu ³⁺ phosphor, red emitting (Zn, Cd) S: Cu
Phosphors and the like are known.

[0004] Bi-activated (Ca, Sr) S phosphors have not been put to practical use because of poor chemical stability, low reproducibility in synthesis, and insufficient luminance and afterglow characteristics. In addition, Cu was activated (Zn, Cd)
S phosphors are hardly used at present because they contain Cd, which is a toxic substance, and have insufficient luminance and afterglow characteristics. On the other hand, the ZnS phosphor activated with Cu has a problem that it is easily decomposed and blackened by ultraviolet rays in the air (particularly in high humidity). It is used indoors as evacuation guidance signs.

On the other hand, oxide-based phosphors include, for example, a calycasite-like structure represented by the chemical composition AAl ₂ O ₄ (where A is composed of magnesium, calcium, strontium or barium) activated with europium. There is an aluminate consisting of the Journal of
Electrochemical Society, Vol. 118, No. 6, p. 930 (1971
Year).

For the purpose of developing a phosphor for a light-emitting screen, Japanese Patent Application Laid-Open No. 58-213080 discloses a chemical composition formula A _1-m Eu _m
Al _q O _{1.5q + 1} (where A is strontium or strontium substituted with up to 25 mol% of calcium, m
And q are reported as aluminate phosphors having compositions corresponding to 0.00 ≦ m ≦ 0.1 and 2 ≦ q ≦ 5, which are orthorhombic (unit cell: a = 24.7575). , b = 4.88
結晶, c = 8.47 Å). This phosphor has been developed for the purpose of improving the emission luminance, and judging from the data of the fluorescence lifetime, the afterglow in practical use is insufficient.

No. 5,376,303 (December 27, 1994)
Japanese Patent No. 2,543,825 (October 16, 1996) and an oxide luminous body having afterglow are reported. The former is represented by the general formula AO.a (Al _1-b B _b ) ₂ O ₃ : cLn
(Wherein, a, b, and c are respectively 0.5 ≦ a ≦ 10.
0, 0 <b ≦ 0.5, 0 <c ≦ 0.2, and AO is Mg
An oxide selected from the group consisting of o, CaO, SrO and ZnO, and Ln is activated by Eu ^{2+ represented} by at least one rare earth metal element selected from the group consisting of Pr, Nd, Dy and Tm in addition to Eu. Alkaline earth aluminates are disclosed. In the latter, AAl ₂ O ₄ (A is magnesium, calcium, strontium or barium)
And alkaline earth aluminates mainly activated by Eu are disclosed.

[0008]

SUMMARY OF THE INVENTION The present inventors have found that SrO
-Al ₂ O ₃ with respect to the monoclinic system and the orthorhombic system aluminates produced in systems, alkaline earth metal element,
Rare earth metal elements, gallium, or silicon or germanium, etc. are partially combined and replaced by solid solution, so that the emission color is controlled and dramatically high brightness, long afterglow,
The present inventors have found that an aluminate phosphor having excellent heat resistance and weather resistance can be obtained, and based on the results, provide a new aluminate phosphor described in detail below.

That is, in the specification of the aforementioned US Pat. No. 5,376,303 and Japanese Patent No. 2,543,825, SrO—Al ₂
The existence of an alkaline earth aluminate luminous body composed of orthorhombic system in the O ₃ system has been reported. On the other hand, the present inventors have found that in the same SrO—Al ₂ O ₃ system, Sr: A
It was discovered for the first time that Sr ₂ Al ₆ O ₁₁ indexed in a monoclinic system can be synthesized from a composition ratio of l = 1: 3 (molar ratio), and the technique is disclosed in a separate application.
This is a self-activating blue-violet luminescent material having a maximum emission peak near 395 nm.

Under these circumstances, the inventors of the present invention have made it possible to further improve the luminance and emission life and to control the position of the maximum emission wavelength by using one or more kinds of rare-earth elements with respect to the luminous body. A new luminous body was synthesized based on activation, solid-solution substitution of an element having a different valence number from aluminum, and the like. As disclosed in a separate application, when synthesizing the monoclinic phase, boron oxide or boric acid is added to improve the reactivity and crystallinity, and further the particle shape and size. Sr ₂ Al ₆ O ₁₁ changes to an orthorhombic system. In addition, the resulting orthorhombic phase is 490 nm
Exhibited blue-green emission having the maximum emission wavelength. Furthermore, when Eu ²⁺ was activated in Sr ₂ Al ₆ O ₁₁ which is a monoclinic phase, the crystal phase could be easily changed to an orthorhombic system. Consequently, this is regardless of whether boric acid is present in the reaction system. It was also found that the emission color of the orthorhombic phase changed from blue-green at 490 nm to yellow-green at 515 nm depending on the amount of Eu ²⁺ added.

Next, the above-mentioned orthorhombic phase, Sr ₂ Al ₆ O ₁₁
As a result of replacing the trivalent aluminum site with a tetravalent ion of silicon or germanium for the purpose of introducing lattice defects into the silicon, defects occur in the cation site due to charge balance, and the aluminate as an orthorhombic phase Was obtained. Despite the non-stoichiometric composition due to the replacement of silicon or germanium ions, the crystal structure as orthorhombic has stabilized. Further, in order to improve the luminance, Eu ²⁺ simultaneously eg Dy ³⁺ and Y ³⁺ to the orthorhombic phase
By co-activating such elements, a long afterglow was also achieved.

In addition, it has been found that, when the molar ratio p of Al ₂ O ₃ / SrO is p <1.5, when aluminum is partially replaced with silicon, the emission color changes from yellow-green to blue-green. Was. Further, in the case of p> 1.5, it was found that when aluminum was replaced with germanium, the emission color changed from blue-green to yellow-green. This indicates that even without adding a flux such as boric acid or the like, a monoclinic aluminate can be a yellow-green luminous body characterized by high luminance and long persistence.

[0013]

Means for Solving the Problems The present invention is based on this finding, and according to the present invention, the chemical composition formula is A ₂ (Al _{1 -z} D _{3 / 4z} □ _{1 / 4z} ) ₆ O _{11 ··· (1) (A 1-} m Eu m) 2 (Al 1-z D 3 / 4z □ 1 / 4z) 6 O 11 ··· (2) (A 1-n-m E n Eu m) _{2 (Al 1-y-z} Ga y D 3 / 4z □ 1 / 4z) 6 O 11 ·· (3) (A 1-n-m-k E 'n Eu m Ln k) 2 (Al 1-y _{-z Ga y D 3 / 4z □} 1 / 4z) 6 O 11 ··· (4) ( where, a is magnesium, calcium, strontium, and one or more alkaline earth metal elements selected from barium, D Is silicon or germanium; E is one or more divalent metal elements selected from manganese and zinc; E 'is manganese , Zinc, bismuth, at least one metal element, □ represents a lattice defect, Ln represents a lanthanide element other than Eu, and m, n, k, y, and z are numerical values in the following ranges, respectively. 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 <k ≦ 0.10 <y ≦ 0.30 <z <0.05), and the crystal system belongs to a monoclinic system or an orthorhombic system.
The present invention provides a high-brightness, long-lasting aluminate phosphor containing an aluminate having a crystal structure that:

Further, according to the present invention, the chemical composition _{formula, (A 1-nmk E '} n Eu m Ln k) O · p ((Al 1-yz Ga y D 3 / 4z □ 1 / 4z) 2 _{O 3) ··· (5) (} A 1-nmk E 'n Eu m Ln' k) O · p ((Al 1-yz Ga y D 3 / 4z □ 1 / 4z) 2 O 3) ··· (5 ′) (where k is a numerical value in the range of 0 ≦ k ≦ 0.1) In a monoclinic aluminate represented by the formula: A high-brightness and long-lasting aluminate phosphor containing a blue or blue-green aluminate is further improved by setting the value of p to 1.5 <p ≦ 1.75. A high-brightness and long-lasting aluminate phosphor containing an acid salt is provided. Sa
Furthermore, Ln ′ in these chemical composition formulas (4 ′) and (5 ′)
Lanthanide elements are dysprosium or neodymium
It is effective to use yttrium as another rare earth element.
is there.

Although the composition and structure of the aluminate according to the present invention are extremely sensitive to the production conditions, as described above, the production conditions can be precisely controlled as can be seen from the examples disclosed below. By doing so, it becomes possible to realize a luminous body having a predetermined luminance, long afterglow, and emission color.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The high-brightness and long-lasting aluminate phosphor according to the present invention basically has a general chemical composition represented by the formula (4) or ( 5). And the expression
In (4), for example, A = Sr, n = m = l = z = y
When = 0, it becomes a crystal represented by the chemical composition formula of Sr ₂ Al ₆ O ₁₁ , which belongs to a monoclinic system. Further, by adding boric acid to the monoclinic phase and re-baking, the phase is changed to the orthorhombic phase, and the afterglow luminance is improved and the emission wavelength is shifted. For example, the maximum emission wavelength changes from 395 nm to a phosphor of 490 nm.

In the equation (4), A = Sr, n = k
When = y = z = 0, it becomes a luminous body represented by the chemical composition formula of (Sr _1-m Eu _m ) ₂ Al ₆ O ₁₁ . 0.1% boric acid
When the mixture is calcined with addition of about 0.5 wt%, a mixture in which the ratio of the orthorhombic phase to the monoclinic phase is almost 50% is obtained. Further, when baking with 1 wt% boric acid, the orthorhombic phase occupies about 80%, and as the amount of boric acid increases, the proportion of the orthorhombic phase also increases. It becomes a single phase of the tetragonal phase. on the other hand,
When baking is performed without adding boric acid, a change from a monoclinic phase to an orthorhombic phase is observed depending on the amount of europium added. When the addition amount m of europium is m <0.03, a single-phase monoclinic crystal is formed. When m is 0.03 ≦ m ≦ 0.05,
The orthorhombic phase gradually becomes mixed, and becomes a single orthorhombic phase when m> 0.05. On the other hand, the emission color of the monoclinic phase is yellow-green having a maximum emission wavelength of around 515 nm, while that of the orthorhombic phase is bluish green having a maximum emission wavelength of around 490 nm. Therefore,
By adjusting the mixing ratio of the monoclinic phase and the orthorhombic phase, the emission color of the phosphor can be freely changed from 490 nm to 515 nm.

In equation (4), A = Sr, D = Si, n
= When m = k = y = 0 is a phosphorescent article represented by the chemical formula of _{Sr 2 (Al 1-z Si} 3 / 4z) 6 O 11. In this case,
Substitution of tetravalent silicon for trivalent aluminum sites causes lattice defects due to charge balance. z
At ≦ 0.005, the phosphor becomes a yellow-green luminescent monoclinic phase with a maximum emission wavelength near 513 nm, but when boric acid is used as a trace flux, a blue-green luminescence with a maximum emission wavelength near 490 nm is obtained. Is obtained. On the other hand, when z> 0.005, blue-green emission with a maximum emission wavelength near 495 nm is exhibited regardless of whether boric acid is added to the reaction system. Furthermore, the maximum emission wavelength shifts to the shorter wavelength side as the silicon content increases.

When boric acid is used as the flux,
An orthorhombic phosphor is obtained, but changes in various factors such as the relative content of boric acid and silicon, the relative content of [boric acid + silicon] and the rare earth element, the type and relative content of the rare earth element. It has been clarified that the structure of the crystal phase (crystal system) and the luminescent color slightly change depending on the temperature. The composition range in which a single orthorhombic phase is obtained is limited to a specific narrow range as can be seen from the examples and the like. In the aluminate phosphor according to the present invention, when the ratio of the orthorhombic phase exceeds 80%,
The emission color is mainly blue-green with a center at 490 nm, and as the proportion of the monoclinic phase increases, a phosphorescent material changed within the range of 460 to 515 nm can be obtained.

When the amount of boric acid is 3 wt% or more based on the total amount of the starting materials, a more stable emission color (blue-green) tends to be easily obtained. But, for example, 18
Even if the amount of boric acid is increased, as in wt%, the maximum emission wavelength cannot be changed from 490 nm to 460 nm as in the case of adding silicon. On the other hand, when the added amount of boric acid is less than 3 wt%, the emission color changes with the lapse of time after the excitation due to the mixed phase of the monoclinic phase and the orthorhombic phase. For example, the emission color immediately after the excitation is yellow-green around 513 nm, and after 30 seconds, it emits blue-green around 490 nm.

(Sr, Eu) (Al _{1 -z} Si _{3 / 4z} ) ₂ O
_With respect to ₄ , even when boric acid is excessively added to the reaction system (for example, 18 wt%), the obtained crystals are monoclinic and do not become orthorhombic. Also, even when a small amount of silicon forms a solid solution, such as when z is 0.0005 or less, the emission color is 52%.
The color changes from yellow-green emission at around 0 nm to blue-green emission at 490 nm. In the composition of the formula (4) of the present invention, considering that the crystal phase changes from the monoclinic phase to the orthorhombic phase even when 0.1 wt% of boric acid is added to the starting material, It is a difference. That is, even in the monoclinic phase, the emission color can be changed from yellowish green at around 513 nm to blue-green emission at 490 nm, and the silicon addition amount z needs to be at least z ≧ 0.005. According to the results of experiments conducted to complete the present invention, the presence or absence of boric acid in the reaction system was sensitive to the crystal structure (expressed as a difference in the crystal system) of the generated crystals, while the solid solution of silicon The substitution was found to be effective in shifting the maximum emission wavelength of the obtained phosphor to a large wavelength.

As described above, when the aluminum site is solid-solution-substituted with silicon, lattice defects occur. The same applies to germanium, which improves the long afterglow observed when europium is activated. Further, when the aluminum site was partially replaced by solid solution with gallium, it was possible to further improve the emission luminance. Equation (4) and Equation
(5) The value (molar value) of y that determines the content of gallium in the glass is 0 <y ≦ 0.3, preferably 0.01 ≦ y ≦
A range of 0.15 is more suitable.

When the element A as a component of the chemical composition formulas (4) and (5) is solid-solution-substituted with the element E 'made of manganese, zinc or bismuth, the emission luminance is improved. More specifically, the substitution amount (molar value) of the element E ′ is 0 ≦ n ≦ 0.
2, preferably in the range of 0.001 <n ≦ 0.05,
It is suitable for improving the light emission luminance, and rather decreases when n> 0.2. Since bismuth is usually trivalent, occupying a divalent site as described above tends to form lattice defects due to charge balance and improve afterglow. On the other hand, when the divalent manganese serving as the emission center was substituted, the emission color changed from blue-green to yellow-green with an increase in the substitution amount. In particular, when no boric acid was added, the yellow-green emission luminance increased.

E contained in the aluminate phosphor of the present invention
The value of m, which determines the composition of u ²⁺ , is 0 ≦ m ≦ 0.
1, preferably in the range of 0.001 ≦ m ≦ 0.06. When the value of m is less than 0.0001, a predetermined luminous intensity cannot be obtained because the amount of ions serving as a luminescence center is small even though the phosphor is a self-activated luminous body. On the other hand, when m exceeds 0.1, "concentration quenching" occurs due to the interaction between emission center ions. At the same time, a compound other than the phase having the desired composition is produced as a by-product, and europium oxide as a raw material remains as an unreacted substance, so that the luminance of the phosphor is greatly reduced.

The amount of Eu ^{2+ serving as} the emission center has a subtle effect on the crystal form and emission color in addition to the luminance. In particular,
The relative content of ^coactivators such as Eu ²⁺ and Dy ³⁺ and the content of boric acid affect the crystal morphology and emission color. The co-activator is
It is necessary to select the type and combination of co-activators according to the expected emission color. For example, Dy ³⁺ and Y ³⁺ , Nd ³⁺ and Y ³⁺
When an appropriate combination of a lanthanide element Ln and another rare earth element is used, a phosphor having high luminance and long afterglow can be obtained. Further, a combination of Dy ³⁺ and Y ³⁺ is preferable as a light accumulator that emits light from blue green to yellow green, and a combination of Nd ³⁺ and Y ³⁺ is preferable as a light accumulator that emits light from blue to blue green.
On the other hand, the added amount of the co-activator is 0 <k ≦ 0.1, preferably
The range of 0.001 ≦ k ≦ 0.03 is more preferable. In particular, when three types of rare earth elements are used in common, the effect on high luminance and long afterglow is enhanced.

The value (molar value) of z for determining the silicon content in the above formulas (4) and (5) must be in the range of 0 ≦ z <0.05, and the solid solution amount With the increase, a deficiency represented by □ occurs at the cation site due to charge balance. In order to improve brightness, the value of z is preferably 0.0
The range of 01 ≦ z ≦ 0.03 is good, and if it exceeds this range, the brightness decreases. It also affects the afterglow. The value of z is z <
When _{0.05, (A 1-nmk E} 'n Eu m Ln k) 2 (Al
Single-phase _{1-yz Ga y D 3 /} 4z □ 1 / 4z) 6 O 11 is obtained. When z ≧ 0.05, in addition to the above compounds, cubic 6SrO.9Al ₂ O ₃ .2SiO _{2 and the} like are by-produced, and a phosphorescent body is obtained by mixing these. Further, when the amount of silicon is increased, the light emission behavior of the phosphor is clearly changed, the maximum emission wavelength is further shifted toward the ultraviolet region, and the afterglow luminance is also reduced.

Of the formulas (4) and (5), boric acid is the most preferable as the flux used in the sintering reaction for obtaining a blue or blue-green phosphor, but when boric acid is added, the maximum emission is obtained. Since the wavelength is fixed at about 490 nm, it is preferable to avoid using boric acid in order to expect another emission color. As described above, the obtained aluminate has a different crystal structure depending on whether boric acid is added. If an excessive amount of boric acid (for example, 18 wt% or more) is used, vitreous coexists in the obtained one, and the emission luminance and the afterglow intensity are extremely deteriorated. However, when an appropriate amount of boric acid of 3 to 8 wt% is added, both the emission luminance and the afterglow intensity are improved. Therefore, it is considered that the deterioration of the emission luminance and the afterglow intensity is caused by the reaction between silica and boric acid to form vitreous material at the aluminate crystal grain boundaries.

In the case where 1.1 <p < 1.5 in the formula (5), even if strontium is the only alkaline earth metal, the emission color changes from blue-green to yellow-green due to solid solution substitution of silicon. I was able to. Furthermore,
In the solid solution substitution of germanium, the emission color can be changed from blue-green to yellow-green when 1.5 <p ≦ 1.75 . These are monoclinic aluminate luminous bodies unless boric acid is added.

The high-brightness and long-lasting aluminate phosphor of the present invention can be heated to room temperature or room temperature after excitation with an electron beam, plasma, ultraviolet or visible light in the range of 200 to 450 nm, or a combination thereof. Above, it is a luminous body exhibiting thermoluminescence (fluorescence) characteristics. The luminous body obtained by the present invention is characterized in that the crystal system is an alkaline earth aluminate having two crystal structures belonging to a monoclinic system and an orthorhombic system, and furthermore, a lanthanide as a luminescence center. It has been demonstrated that by activating the element, high luminance and long afterglow can be provided. The difference in the crystal structure varies depending on the kind of the alkaline earth element or the lanthanide element, or a combination thereof, and the amount of silicon or germanium added.

In the production of the high-brightness and long-lasting aluminate phosphor according to the present invention, basically, a compound containing the element A in the chemical composition formula (4) or (5) as a main raw material is used. , A compound containing E ′ element, a compound containing Al element, G
A compound containing element a, a compound containing element D (compound of Si or silicon or Ge), a compound containing Eu as an activator, a compound containing Ln rare earth element, and the like are used. Specifically, the compound is used in the form of an oxide containing each of the above-described elements, or a salt such as a carbonate, a nitrate, or a chloride which can be easily turned into an oxide by firing, and has a chemical composition formula
They are weighed so as to have a composition range represented by (4) or (5), and they are sufficiently mixed by a wet or dry method to obtain a raw material powder.

Next, the mixed powder was pressed and molded at a pressure of up to 1000 kg / cm ² , placed in a heat-resistant reaction vessel such as an aluminum crucible, and placed in a reducing atmosphere of a hydrogen-containing inert gas. At a temperature of 1000 to 1500 ° C. for 2 to 10 hours to obtain the phosphorescent material as a powdery product. When baking is repeated twice or more, the first baking may be performed in air, but the final baking step must be performed in a reducing atmosphere. It is desirable, but not necessary, to add a flux other than boron oxide or boric acid to promote the reaction, control the crystal morphology, and control the particle size. In addition, depending on the intended luminescence characteristics, the type and amount of the flux and the procedure for adding them in the process, and further, by selecting the type and amount of the added element for the purpose of solid solution replacement, A phosphorescent material having a crystal structure, an emission wavelength, an emission intensity, and an emission lifetime can be synthesized. It is preferable that the obtained phosphor is pulverized to 30 μm or less, and this powder is uniformly mixed with a polyester resin or the like, and molded and used as various molded articles.

The time-dependent change in the luminescence intensity described later is determined by uniformly mixing the obtained powder of the phosphor with a polyester resin or the like so that the phosphor and the polyester resin have a weight ratio of 1: 2. The mixture was formed into a sheet, dried, and irradiated with the sample for 30 minutes at a distance of 100 mm using a 15 W tabletop white fluorescent lamp in a dark room 24 hours after light shielding, and the change in the emission intensity was measured.

The heat resistance test was performed as follows. That is, the powder obtained by grinding the aluminate phosphor to 30 μm or less
Only 10 g was weighed, placed in an alumina crucible, and heated in an electric furnace at 750 ° C. for 2 hours in the air. With respect to the sample thus obtained, a luminance retention ratio was obtained from the results of luminance measurement before and after heating.

Further, the water resistance was examined as follows. That is, a volume of 300 ml containing 200 ml of distilled water
Into a ml beaker, exactly 10 g of the phosphor powder pulverized to 30 μm or less was weighed, added, stirred for 2 hours with a magnetic stirrer, and kept at 40 ° C. and 80 ° C. for 100 hours. Then, from the results of the luminance measurement before and after the processing, a luminance maintenance ratio was obtained.

[0035]

The present invention will be described in more detail with reference to the following examples. In the following, for convenience, the above formula
_{(4), (A 1-nmk E '} n Eu m Ln k) 2 (Al 1-yz Ga y
It marked _{D 3 / 4z) 6 O 11} , also Equation (5) _{is, (A 1-nmk E '} n Eu m Ln k) O · p ((Al 1-yz
_{Ga y D 3 / 4z) 2} O 3) and referred.

Example 1 Sr ₂ (Al _{1 -z} Si _{3 / 4z} )
_In the chemical composition formula of ₆ O _11, the amount of silicon added is z = 0.
01, and no boric acid was added in Example 1-1.
In Table 2 under the condition of adding boric acid (H ₃ BO ₃ ) at 3 wt%, Table 1
Raw material SrC so that the starting raw material mixing ratio (amount) shown in
O ₃ , Al ₂ O ₃ , and SiO ₂ were accurately weighed, an appropriate amount of distilled water was added, and wet mixing was performed in a ball mill for 20 hours. Next, the mixed powder dried at 100 ° C. is molded into a disc having a diameter of 40 mmφ with a load of 1000 kg / cm ² by a mold molding machine, placed in an alumina crucible, and containing 3% hydrogen in an electric furnace. It was calcined at 1400 ° C. for 2 hours in argon gas. The sample collected after cooling was further finely pulverized using an alumina mortar, molded into a disk by a mold molding machine, and rebaked under the same conditions as at the beginning.

The obtained sample was subjected to powder X-ray diffraction and measurement of excitation and emission spectra. As a result, it was found that Example 1-1 in which boric acid was not added had a monoclinic phase. Example 1 in which boric acid was added at 3 wt%
In No. 2, it was confirmed that it was an orthorhombic phase. In FIG. 1 (a),
The excitation spectrum of monoclinic Sr ₂ (Al _0.99 Si _0.0075 ) ₆ O ₁₁ and the emission spectrum of the sample excited by 246 nm ultraviolet light are shown in FIG. From this figure, it can be seen that the first embodiment
It can be seen that the sample of -1 is a self-activating phosphor having a maximum emission wavelength near 395 nm. On the other hand, the maximum emission wavelength of the orthorhombic Sr ₂ (Al _0.99 Si _0.0075 ) ₆ O _{11 of} Example 1-2 was around 400 nm.

[0038]

[Table 1]

[Example 2]

[Table 2]

[0040]

[Table 3]

In Table 2, Examples 2-1 to 2-
At the starting raw material mixing ratio (amount) shown as 6, (Sr _0.995 E
u _0.005 ) ₂ (Al ₁ -z Si _{3 / 4z} ) ₆ O ₁₁ The amount z of silicon is changed to z = 0, 0.005, 0.02, 0.05, 0.1 and 0.20, and 5 wt% of boric acid is further added. Each sample was prepared. FIG. 2A shows a case where z = 0.02, and FIG. 2B shows a case where z = 0.
5 shows a powder X-ray diffraction pattern in the case of No. 05. In this example in which boric acid was added in an amount of 5 wt%, a single-phase orthorhombic system (S
r _0.995 Eu _0.005 ) ₂ (Al _{1 -z} Si _{3 / 4z} ) ₆ O ₁₁ was obtained. On the other hand, when z ≧ 0.05, 6 belonging to the cubic system
SrO.9Al ₂ O ₃ .2SiO ₂ is by-produced and z ≧ 0.1
Became a single phase. Table 3 summarizes the maximum excitation wavelengths of these samples and the maximum emission wavelengths of the samples excited by irradiation with ultraviolet light of 246 nm. With the increase in the amount of silicon added, the maximum emission wavelength is between 403 and 407 nm and between 465 and 488 nm.
It turns out that there is something that shifts widely with m.

In the same manner as in Embodiment 1, an embodiment to be described later
2-7 and Comparative Example 1 without adding boric acid, z = 0.
005 (Example 2-7) , 0.05 and 0.20 samples were synthesized.
When z = 0.005, the monoclinic system (Sr _0.995 Eu
_0.005 ) ₂ (Al _0.995 S
i _0.0038 ) ₆ O ₁₁ , and it was found that at z = 0.05, a mixed phase of monoclinic and cubic was obtained, and at z = 0.2, a cubic phase was obtained. Here, the cubic phase is 6SrO.
It is a 9Al ₂ O ₃ · 2SiO _2. The maximum emission wavelengths were 513 nm, 508 nm and 465 nm at the respective added amounts, and shifted from 513 nm to 465 nm according to the added amount of silicon. Since the blue phase due to the addition of silicon was observed in both monoclinic and orthorhombic crystal phases, it was found that the blue shift was deeply related to the formation of the cubic phase. Moreover, the shift width is wider in the case where boric acid is not added.

Example 3 (Sr _0.999 Eu _0.001 ) ₂
(Al _0.98 Ge _0.015 ) ₆ O ₁₁ was synthesized by the same method as in Example 1 with the mixing ratio of the raw materials shown as Example 3 in Table 2. In addition, 3 wt% of boric acid was added. From the powder X-ray diffraction pattern, the obtained sample was identified to be an orthorhombic phase. FIGS. 3 (a) and 3 (b) show the excitation spectrum of this sample and the emission spectrum excited by ultraviolet light of 260 nm. Due to the substitution of germanium element, the maximum emission wavelength is around 513 nm even though the emission wavelength is a system to which boric acid is added. That is, the addition of the germanium element has the effect of shifting the emission wavelength of (Sr, Eu) ₂ Al ₆ O _{11 to} a longer wavelength side than 490 nm.

Example 4 As shown in Table 2 as Examples 4-1 and 4-2, when boric acid was added at 5 wt%, the chemical formula (Sr _0.982 Eu _0.005 Dy _0.008 Y
_0.005 ) ₂ (Al _1-z Si _{3 / 4z} ) ₆ O ₁₁ , and a sample in which the proportion of silicon is (a) z = 0 and (b) z = 0.02 was used in the same manner as in Example 1. And synthesized.

FIGS. 4A and 4B show X-ray powder diffraction patterns by CuKα radiation, and Table 4 shows X-ray diffraction data (distance between lattice planes). Samples (a) and (b) are both indexed in the orthorhombic system. (Sr _0.982 Eu _0.005 Dy
_0.008 Y _0.005 ) ₂ Al ₆ O ₁₁ has a lattice constant of a = 24.
795Å, b = 4.894Å, c = 8.510Å. on the other hand,
(Sr _0.982 Eu _0.005 Dy _0.008 Y _0.005 ) ₂ (Al
_{In 0.98} Si _0.015 ) ₆ O ₁₁ , the lattice constant is a = 24.816
Ｂ, b = 4.894Å, c = 8.519Å. a-axis and b
Since the axis is elongated, it is considered that silicon having an ionic radius larger than that of aluminum was dissolved. FIG.
(a) shows the excitation spectrum of the sample, and FIG. 5 (b) shows the emission spectrum of the sample when excited by 240 nm ultraviolet light. From the figure, it can be seen that the peak of the maximum light emission intensity is a blue-green phosphor having a peak near 487 nm. Contains no silicon (Sr
It was also confirmed that the sample of _0.982 Eu _0.005 Dy _0.008 Y _0.005 ) ₂ Al ₆ O ₁₁ had the maximum emission intensity around 490 nm.

The sample obtained in this example was
After leaving it in a dark room for 48 hours, apply 15 W to the sample from a distance of 100 mm.
A tabletop white fluorescent lamp was irradiated for 30 minutes, and the time change (afterglow characteristic) of the emission intensity at 487 nm was measured. Table 5 shows that Sr _{0.98 2} Eu _0.005 Dy _0.008 Y synthesized as Comparative Example 2 described later.
_0.005 Al _1.98 Si _0.015 O ₄ represents the relative luminance obtained with the emission luminance of 100%. The afterglow luminance after 1 to 3 hours is about three times as high as that of the sample of the comparative example.

[0047]

[Table 4]

[0048]

[Table 5]

[Embodiment 5]

[Table 6]

As shown in the starting material mixing ratio (amount) in Table 6, in Example 5-1, z = 0.03 and (Sr _0.982 Eu _0.005 Dy _0.008 Y _0.005 ) ₂ (Al
_In Example 5-2, the chemical formula of _0.97 Si _0.0225 ) ₆ O ₁₁ , where z = 0.04, (Sr _0.982 Eu _0.005 Dy _0.008 Y _0.005 ) ₂ (Al
_In the chemical formula of _0.95 Ga _0.01 Si _0.03 ) ₆ O ₁₁ and Example 5-3, when z = 0.05, (Sr _0.982 Eu _0.005 Dy _0.008 Y _0.005 ) ₂ (Al
_0.95 Si _0.038 ) ₆ O ₁₁ , and H ₃ BO ₃
Was added in an amount of 8 wt%, and synthesis was performed in the same manner as in Example 1.

[0051] than the powder X-ray diffraction pattern, the sample of Example 5-1, orthorhombic _{(Sr 0.982 Eu 0. 005 Dy 0.008} Y
_0.005) was found to be _{2 (Al 0.97 Si 0.0225) 6} O 11. In the sample of Example 5-2, in addition to the orthorhombic system,
A small amount of cubic _{6Sr · 9Al 2 O 3 · 2SiO} 2 are mixed, in Example 5-3, was much cubic phase. Chemical composition (Sr, Eu, Dy, Y ) 2 (Al 1-yz Ga y S
In i _{3 / 4z} ) ₆ O ₁₁ , it was found that the composition region in which a solid solution of silicon was obtained was very narrow, and the solid solution limit was also low.

With respect to the emission intensity around 485 nm, the change with time (afterglow characteristic) was measured. As a result, in the above sample, when the added amount of silicon was large, the sample became a mixed sample with a cubic phase, so that the emission intensity tended to decrease. It was observed. It has been found that the addition amount of silicon is suitably in the range of 0.001 ≦ z <0.05, and more preferably in the range of 0.001 ≦ z ≦ 0.03, as a long afterglow phosphor.

[Embodiment 6]

[Table 7]

In the mixing ratio (amount) of the starting materials in Table 7, (Sr _0.982 Eu _0.005 Dy _0.008 ) corresponding to p = 1.6 in the formula (4).
Y _0.005 ) _O.1.6 (Al _1.99 Ge _0.0075 O ₃ ) was synthesized by repeating baking twice at 1500 ° C. for 2 hours in an argon gas containing 3% hydrogen without adding boric acid. . The obtained product was a phase belonging to a monoclinic system, and the peak giving the maximum emission intensity was a yellow-green phosphor having a wavelength of 513.5 nm.

[Example 7] Heat resistance test: (Sr _0.982 Eu _0.005 Dy _0.008 Y obtained in the present invention)
_0.005 ) ₂ Al ₆ O ₁₁ powder and (Sr _0.982 Eu)
_{0.005 Dy 0.008 Y 0.005) 2 (} Al 0.98 Si 0.01 5)
₆ O ₁₁ powder (30 μm or less) was placed in an alumina crucible and heated at 750 ° C. for 2 hours in air using an electric furnace. For comparison, a sample Sr _0.982 Eu of Comparative Example 3 described later was used.
The _{0.005 Dy 0.008 Y 0. 005 Al 2} O 4, was treated in the same manner under the conditions of the present embodiment. The sample of this example did not show any particular color change in appearance even after the heat treatment, but the sample of the comparative example was confirmed to be white with the naked eye after the treatment.

Table 8 summarizes the results of the change over time (afterglow characteristics) of the 486 nm emission intensity. In the same table, the relative afterglow luminance is expressed in the form of a maintenance ratio, with the luminance before the heat treatment being 100% for each sample. According to the test results, after heat treatment, the sample containing no silicon has extremely low afterglow luminance, whereas the sample containing no silicon (Sr _0.982 Eu _0.005 D
y _0.008 Y _0.005 ) ₂ (Al _0.98 Si _0.015 ) ₆ O ₁₁ shows almost the same luminance even after 180 minutes. In other words, it can be seen that this new phosphor has excellent heat resistance especially when silicon is added.

[Example 8] Water resistance test: Pulverized to a powder of 30 µm or less with a ball mill (Sr
_{0.982 Eu 0.005 Dy 0.00 8 Y 0.005} ) 2 (Al 0.98 S
The i _{0.015) 6} O ₁₁ were weighed into 10 g, in addition to the 300 ml beaker containing 200 ml of distilled water to prepare a slurry. Next, the mixture was stirred with a magnetic stirrer for 2 hours, and then kept at 40 ° C and 80 ° C for 100 hours. Assuming that the luminance before the processing is 100, the luminance after the processing is relatively shown in Table 9.
The luminance of the luminous body obtained in the present invention did not change at all despite the processing conditions of 80 ° C.

[0058]

[Table 8]

[0059]

[Table 9]

[0060]

[Table 10]

[Comparative Example 1 , Example 2-7 ] As shown in Table 10, the starting material compounding ratio (amount) (Sr
_0.995 Eu _0.005 ) ₂ (Al _1-z Si
_{3 / 4z} ) ₆ O ₁₁ and z = 0.005 (Example 2)
7), and 0.05,0.2, a case of not adding boric acid, implementation
As Example 2-7 and Comparative Example 1, they were synthesized in the same manner as in Example 1. The measurement results of the powder X-ray diffraction pattern and the excitation / emission spectrum of the sample are described in the section of [Example 2].

Comparative Example 2 As Comparative Example 2, as shown in Table 10, Sr 0.982 Eu of a system to which boric acid was added at 5 wt% was used.
_0.005 Dy _0.008 Y _0.005 Al _1.98 Si _0.015 O ₄ was synthesized in the same manner as in Example 1. The obtained phase can be assigned to a monoclinic system, and is a phosphorescent substance having a maximum emission intensity around 490 nm and having excellent heat resistance and water resistance (see Japanese Patent Application No. 9-238966). In the section of [Example 4], the afterglow characteristic is shown in comparison with the sample of Example 4.

Comparative Example 3 As Comparative Example 3, as shown in Table 10, Sr0.982Eu of a system containing 5 wt% of boric acid was added.
_0.005 Dy _0.008 Y _0.005 Al ₂ O ₄ was also synthesized in the same manner as in Example 1. The obtained product was composed of a monoclinic system, and the powder X-ray diffraction pattern showed that it was a single phase having a known stuffed tridymite structure. This is a yellow-green luminescent material having a peak at around 520 nm which gives the maximum emission intensity when excited by ultraviolet light of 360 nm.
The heat resistance is described in [Example 7] in comparison with the luminous body of the present invention.

[0064]

According to the high-brightness and long-lasting aluminate phosphor of the present invention described in detail above, not only is it a self-activating luminous body, but also by controlling the selection and amount of solid solution elements. ,
High emission brightness and afterglow characteristics (afterglow brightness and afterglow time) due to activation of lanthanide element, etc. in addition to rich polychromaticity
It has heat resistance, weather resistance, not only severe natural environmental conditions consisting of high temperature and humidity, but also underwater, underwater,
It is possible to obtain a luminous body that can maintain sufficient performance even when placed in warm water.

[Brief description of the drawings]

1 (a) shows the excitation spectrum (monitor: 395 nm) of the luminous body of Example 1-1 of the present invention, and FIG. 1 (b) shows the emission spectrum (monitor: 246 nm) of the luminous body of Example 1-1. It is a graph shown.

2 (a) is a diagram showing a powder X-ray diffraction pattern of the luminous body of Example 2-3 (z = 0.02) of the present invention, and FIG. 2 (b) is a diagram showing Example 2-4 of the present invention (z = 0.02). FIG. 3 is a diagram showing a powder X-ray diffraction pattern of the luminous body (z = 0.05).

FIG. 3 (a) shows the excitation spectrum (monitor: 513 nm) of the luminous body of Example 3 of the present invention, and FIG. 3 (b) shows the luminous spectrum (monitor: 260 nm) of the luminous body of the same example. It is a graph.

FIG. 4A shows a case where z = 0 in Example 4 of the present invention.
(b) is a diagram showing a powder X-ray diffraction pattern when z = 0.01.

FIG. 5 (a) shows an excitation spectrum (monitor: 487 nm) of the phosphor of Example 4 of the present invention, and FIG. 5 (b) shows an emission spectrum (monitor: 240 nm) of the phosphor of the embodiment. It is a graph.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09K 11/64 CPM C09K 11/66 CA (STN)

Claims (10)

(57) [Claims] The chemical composition is represented by A ₂ (Al _1-z D _{3 / 4z} □ _{1 / 4z} ) ₆ O ₁₁ (where A is one selected from magnesium, calcium, strontium and barium). More than one kind of alkaline earth metal element, D is silicon or germanium,
□ represents a lattice defect, and z is a numerical value satisfying the following range. 0 <z <0.05 ), and the crystal system belongs to monoclinic system or orthorhombic system
Aluminate phosphor with excellent heat and weather resistance containing aluminate having a crystalline structure . 2. A chemical composition _{formula, (A 1-m Eu m} ) 2 (Al 1-z D 3 / 4z □ 1 / 4z) 6 O 11 ( where, A in the formula is magnesium, calcium, strontium And at least one alkaline earth metal element selected from barium and D is silicon or germanium;
□ indicates a lattice defect, and m and z are numerical values satisfying the following ranges. 0 <m ≦ 0.10 <z <0.05), and the crystal system belongs to monoclinic system or orthorhombic system
High-luminance aluminate phosphor with excellent heat and weather resistance containing aluminate with a crystalline structure . 3. A chemical composition _{formula, (A 1-n-m} E n Eu m) 2 (Al 1-y-z Ga y D 3 / 4z □ 1 / 4z) 6 O 11 ( where in the formula A is at least one kind of alkaline earth metal element selected from magnesium, calcium, strontium and barium, E is at least one kind of divalent metal element selected from manganese and zinc, D is silicon or germanium, and □ is composition represents a defect, m, n, y, z are represented respectively of numbers satisfying the following range. 0 ≦ m ≦ 0.1 0 ≦ n ≦ 0.2 0 <y ≦ 0.3 0 <z <0.05), crystals System belongs to monoclinic or orthorhombic system
Of crystalline structure monoclinic or orthorhombic Al <br/> heat and weather resistance in good high luminance aluminate phosphorescent article comprising a Min acid salt of the. 4. A chemical composition _{formula, (A 1-n-m} -k E 'n Eu m Ln k) 2 (Al
_{1-y-z Ga y D} 3 / 4z □ 1 / 4z) 6 O 11
(Where A is one or more alkaline earth metal elements selected from magnesium, calcium, strontium and barium, E ′ is one or more metal elements selected from manganese, zinc, bismuth, D Represents silicon or germanium, Ln represents a lanthanide element other than Eu, and m, n, k, y, and z are numerical values satisfying the following ranges, respectively: 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 <k ≦ 0.10 <y ≦ 0.30 <z <0.05), and the crystal system belongs to monoclinic system or orthorhombic system
High luminance and long afterglow aluminate phosphor with excellent heat and weather resistance containing aluminate with a crystalline structure . 5. The chemical composition _{formula, (A 1-n-m} -k E 'n Eu m Ln k) O · p ((Al 1-y-z Ga y D 3 / 4z □ 1 / 4z) 2 O ₃ ) (where A is one or more kinds of alkaline earth metal elements selected from magnesium, calcium, strontium and barium, and E ′ is one or more kinds of metal elements selected from manganese, zinc and bismuth) The element, D is silicon or germanium, Ln is a lanthanide element other than Eu, and m, n, k, p, y, and z are numerical values satisfying the following ranges, respectively: 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 ≦ k ≦ 0.1 1.1 <p <1.50 <y ≦ 0.30 <z <0.05) High brightness with excellent heat and weather resistance including a monoclinic blue or bluish green aluminate Long afterglow aluminate phosphor. 6. The chemical composition _{formula, (A 1-n-m} -k E n Eu m Ln k) O · p ((Al 1-y-z Ga y D 3 / 4z □ 1 / 4z) 2 O ₃ ) (where A is at least one kind of alkaline earth metal element selected from magnesium, calcium, strontium and barium, E is at least one kind of metal element selected from manganese, zinc, bismuth, D Represents silicon or germanium, Ln represents a lanthanide element other than Eu, and m, n, k, p, y, and z are numerical values satisfying the following ranges, respectively: 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 ≦ k ≦ 0.1 1.5 <p ≦ 1.75 0 <y ≦ 0.30 <z <0.05) A high-brightness and long-lasting alumina having excellent heat and weather resistance containing a monoclinic yellow-green aluminate Phosphate phosphor. 7. A chemical composition _{formula, (A 1-n-m} -k E 'n Eu m Ln' k) 2 (Al
_{1-y-z Ga y D} 3 / 4z □ 1 / 4z) 6 O 11
(Where A is one or more alkaline earth metal elements selected from magnesium, calcium, strontium and barium, E ′ is one or more metal elements selected from manganese, zinc, bismuth, D Represents silicon or germanium, Ln 'represents a combination of a lanthanide element other than Eu and another rare earth element, and m, n,
k, y, and z are numerical values that satisfy the following ranges. 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 <k ≦ 0.10 <y ≦ 0.30 <z <0.05), and the crystal system belongs to monoclinic system or orthorhombic system
High luminance and long afterglow aluminate phosphor with excellent heat and weather resistance containing aluminate with a crystalline structure . 8. The chemical composition _{formula, (A 1-n-m} -k E 'n Eu m Ln' k) O · p ((Al 1-y-z Ga y D 3 / 4z □ 1 / 4z) ₂ O ₃ ) (where A is one or more alkaline earth metal elements selected from magnesium, calcium, strontium and barium, and E ′ is one or more alkaline earth metal elements selected from manganese, zinc and bismuth. A metal element, D is silicon or germanium, Ln 'is a combination of a lanthanide element other than Eu and another rare earth element, m, n,
k, p, y, and z are numerical values that satisfy the following ranges. Heat resistance including monoclinic blue or bluish green aluminate represented by 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 ≦ k ≦ 0.1 1.1 <p <1.50 <y ≦ 0.30 <z <0.05) High brightness and long afterglow aluminate phosphor with excellent weather resistance. 9. The chemical composition _{formula, (A 1-n-m} -k E n Eu m Ln 'k) O · p ((Al 1-y-z Ga y D 3 / 4z □ 1 / 4z) 2 O ₃ ) (where A is one or more kinds of alkaline earth metal elements selected from magnesium, calcium, strontium and barium, and E is one or more kinds of metal elements selected from manganese, zinc and bismuth) , D represents silicon or germanium, Ln ′ represents a combination of a lanthanide element other than Eu and another rare earth element, and m, n, k,
p, y, and z are numerical values that satisfy the following ranges. Heat resistance and weather resistance including a monoclinic yellow-green aluminate represented by 0 ≦ m ≦ 0.10 ≦ n ≦ 0.20 ≦ k ≦ 0.1 1.5 <p ≦ 1.75 0 <y ≦ 0.30 <z <0.05) High brightness and long afterglow aluminate phosphor. 10. A high-brightness, long-lasting aluminate phosphor excellent in heat resistance and weather resistance according to claim 7, wherein the lanthanide element is dysprosium or neodymium.
The other rare earth element is yttrium.