JPH10279934A - Phosphor - Google Patents

Abstract

(57) [Summary] [Problem] Blue to blue from ultraviolet region by long wavelength ultraviolet excitation
It is an object of the present invention to provide a novel phosphor having a red emission color. SOLUTION: Composition formula M ¹ M ² ₂ (Ln, Ln ′) O ₄
Is a phosphor represented by (Wherein M ¹ is Li, Na,
At least one monovalent metal element selected from the group consisting of K, Rb and Cs, and M ² is Ca, Sr, Ba, Be, Mg,
Ln is at least one element selected from the group consisting of Y, La, Gd and Lu, and Ln 'is Ce, Pr, N
At least one element selected from the group consisting of d, Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb is shown. )

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare-earth phosphor which emits light mainly in an ultraviolet to visible wavelength region by excitation of an electron beam, an X-ray, an ultraviolet ray or the like, particularly an ultraviolet ray.

[0002]

2. Description of the Related Art Phosphors that emit light when excited by ultraviolet rays (ultraviolet excited phosphors) are widely used in fluorescent lamps, color plasma displays, high-pressure mercury lamps, fluorescent wall materials used indoors and outdoors, decoration with fluorescent tiles, and the like. Has been
Fluorescent wall materials, fluorescent tiles, and the like need to be excited by long-wavelength (365 nm) ultraviolet light, particularly among ultraviolet rays, to emit light of various colors brightly.

Conventionally, as a long-wavelength ultraviolet-excited phosphor,
A blue-emitting Eu ²⁺ activated alkaline earth halophosphate phosphor,
Eu ²⁺ -activated alkaline earth aluminate phosphor, etc., green-emitting Zn ₂ GeO ₄ : Mn phosphor, etc., and red-emitting phosphor Y ₂ O ₂ S: Eu or YVO ₄ : Eu phosphor, etc. Has been put to practical use.

[0004] However, with the diversification of display and the enhancement of functions,
There are demands for multicolor emission, higher luminance, improved weather resistance, and the like. However, conventional phosphors are limited in the types of luminescent colors, and are therefore practical fluorescents that emit light of various colors. There is a demand for body development.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a novel phosphor which emits light mainly in the ultraviolet region to the visible region from blue to red under the excitation of long wavelength ultraviolet light.

[0006]

The configuration of the present invention is as follows. (1) A phosphor represented by the following composition formula. _{^{M 1 M 2 2 (Ln,}} Ln ') O 4 ( wherein, M ¹ is Li, a monovalent metal element of one or more selected Na, K, from the group of Rb and Cs, M ² is C
a, Sr, Ba, Be, Mg, Zn, and at least one divalent metal element selected from the group of Cd;
a, Gd and Lu are at least one rare earth metal element selected from the group consisting of Ce, Pr, Nd, Sm, E
One or more lanthanide group elements selected from the group consisting of u, Tb, Dy, Ho, Er, Tm, and Yb are respectively shown. )

(2) A phosphor represented by the following composition formula: ^{_{M 1 M 2 2 (Ln 1}} -X, Ln 'X) O 4 ( wherein, M ¹ is Li, Na, K, a monovalent metal element of one or more selected from the group of Rb and Cs, M ² is C
a, Sr, Ba, Be, Mg, Zn, and at least one divalent metal element selected from the group of Cd;
a, Gd and Lu are at least one rare earth metal element selected from the group consisting of Ce, Pr, Nd, Sm, E
u, Tb, Dy, Ho, Er, Tm, and Yb each represent one or more lanthanide group elements selected from the group, and x is a number in the range of 1 × 10 ⁻⁵ ≦ x ≦ 8 × 10 ^−1. is there. )

(3) In the above composition formula, x is 1 × 10 ⁻³ ≦ x ≦
(1) wherein the number is in the range of 5 × 10 ^−1.
Or the phosphor according to (2).

(4) In the above composition formula, M ¹ is Li and M
Wherein ² is Sr and Ln is Y
The phosphor according to any one of (1) to (3).

(5) In the above formula, the activator Ln 'of the phosphor is used.
Is Eu and / or Tb.
The phosphor according to any one of items (1) to (4).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Typical specific examples of the phosphor composition of the present invention are as follows. LiSr
₂ (Y _{1 -X} , Eu _X ) O ₄ , LiSr ₂ (Y _{1 -X} , Tb
_X ) O ₄ , LiSr ₂ (Y _1-x , Ce _x ) O ₄ , LiS
r ₂ (Y _1-x , Pr _x ) O ₄ , LiSr ₂ (Y _1-x , N
d _x ) O ₄ , LiSr ₂ (Y _1-x , Sm _x ) O ₄ , Li
Sr ₂ (Y _1-X , Dy _X ) O ₄ , LiSr ₂ (Y _1-X ,
_{Ho X) O 4, LiSr 2} (Y 1-X, Er X) O 4, L
iSr ₂ (Y _1-x , Tm _x ) O ₄ , LiSr
₂ (Y _{1 -X} , Yb _X ) O ₄ , LiCa ₂ (Y _{1 -X} , Eu
_X ) O ₄ , LiCa ₂ (Y _1-X , Tb _x ) O ₄ , LiB
a ₂ (Y _{1 -X} , Eu _X ) O ₄ , LiBa ₂ (Y _{1 -X} , T
b _x ) O ₄ , LiBe ₂ (Y ₁ -x, Eu _x ) O ₄ , Li
Be ₂ (Y _1-X , Tb _X ) O ₄ , LiMg ₂ (Y _1-X ,
Eu _x ) O ₄ , LiMg ₂ (Y _1-x , Tb _x ) O ₄ , L
iZn ₂ (Y _1-X , Eu _X ) O ₄ , LiZn
₂ (Y _{1 -X} , Tb _X ) O ₄ , LiCd ₂ (Y _{1 -X} , Eu
_X ) O ₄ , LiCd ₂ (Y _1-x , Tb _x ) O ₄ , NaS
r ₂ (Y _{1 -X} , Eu _X ) O ₄ , NaSr ₂ (Y _{1 -X} , T
b _X ) O ₄ , KSr ₂ (Y _1-X , Eu _X ) O ₄ , KSr
₂ (Y _{1 -X} , Tb _X ) O ₄ , RbSr ₂ (Y _{1 -X} , Eu
_X ) O ₄ , RbSr ₂ (Y _{1 -X} , Tb _X ) O ₄ CsSr ₂ (Y _{1 -X} , Eu _X ) O ₄ , CsSr ₂ (Y
_1-X , Tb _x ) O ₄

The phosphor of the present invention is manufactured as follows. A phosphor composed of an oxide of each of the M ¹ element, M ² element, Ln element, and Ln ′ element serving as an activator or a salt such as a carbonate, a nitrate, or a halide which easily becomes an oxide upon firing. The raw materials are stoichiometrically weighed in such a ratio as to give the above composition formula, and mixed well by a wet or dry method. The raw material mixture may be formed into a pellet by pressure. Further, the compound of Ln and the compound of Ln ′, which are rare earth materials, may be dissolved in water or the like, and then coprecipitated and mixed.

Next, a low-melting point compound conventionally used in the production of a phosphor, such as an alkali halide or an ammonium halide, is added to the mixture as a flux, if necessary, and mixed into the phosphor raw material. This mixture is filled in a heat-resistant container such as an alumina crucible, and kept in air or in a neutral gas atmosphere.
It is baked once or more for 8 hours, preferably at 700 to 900 ° C. for 24 to 48 hours. This baked product is crushed, washed with water,
Drying, sieving and the like are performed to obtain the phosphor of the present invention. At this time,
In particular, when the Ln 'element of the activator is Tb or Ce, the final baking in a reducing atmosphere can further increase the emission luminance of the phosphor.

The x value representing the amount of the activator Ln 'is 1
It is adjusted in the range of x10 ^-5 ≤ x ≤ 8 x 10 ^-1 . x value is 1
When the value is less than x10 ^-5 , the obtained phosphor hardly emits light, and when the x value exceeds 8 × 10 ^-1 , concentration quenching occurs, and the emission intensity of the phosphor is remarkably reduced. In addition, from the viewpoint of the emission intensity of the obtained phosphor, x
The value is particularly preferably in the range of 1 × 10 ⁻³ ≦ x ≦ 5 × 10 ⁻¹ .

FIG. 1 shows one of the phosphors of the present invention, Li.
FIG. 2 is an example of an X-ray diffraction diagram confirming the crystal structure of a Sr ₂ Y _0.85 Eu _0.15 O ₄ phosphor.

FIG. 2 shows Li, which is one of the phosphors of the present invention.
This shows an emission spectrum when the Sr ₂ Y _0.85 Eu _0.15 O ₄ phosphor was excited by 365 nm ultraviolet rays, and the emission peak wavelength was 612 nm.

FIG. 3 shows one of the phosphors of the present invention, Li.
This shows an emission spectrum when the Sr ₂ Y _0.9 Tb _0.1 O ₄ phosphor was excited by ultraviolet light of 365 nm, and the emission peak wavelength was 552 nm.

The emission spectrum of the phosphor of the present invention shows that, as long as the activator element (Ln ') is the same, a phosphor composed of a host element other than the above-mentioned phosphor exhibits almost the same emission spectrum. I have confirmed. The activator (L
When a rare earth element other than Eu or Tb was used as n ′), a phosphor exhibiting emission of a light emission color specific to the used activator element under ultraviolet excitation was obtained.

FIG. 4 exemplifies an excitation spectrum of the LiSr ₂ Y _0.85 Eu _0.15 O ₄ phosphor. The excitation spectrum was measured by fixing the spectral wavelength on the output side of the spectrophotometer to 612 nm, which is the peak wavelength of the emission spectrum of each phosphor, and changing the wavelength of the excitation light applied to the sample.
The intensity of the output light at 12 nm is plotted, the vertical axis represents the relative emission intensity on the output side (each emission wavelength), the horizontal axis represents the wavelength of the excitation light to be scanned, and the peak wavelength of this spectrum is the highest for this phosphor. This is the wavelength at which light can be emitted efficiently.

FIG. 5 illustrates an excitation spectrum of the LiSr ₂ Y _0.9 Tb _0.1 O ₄ phosphor. The excitation spectrum was measured by fixing the spectral wavelength on the output side of the spectrophotometer to 552 nm, which is the peak wavelength of the emission spectrum of each phosphor, and changing the wavelength of the excitation light applied to the sample.
The intensity of the output light at 52 nm is plotted, the vertical axis represents the relative emission intensity on the output side (each emission wavelength), the horizontal axis represents the wavelength of the excitation light to be scanned, and the peak wavelength of this spectrum is the highest for this phosphor. This is the wavelength at which light can be emitted efficiently.

FIG. 6 is a graph showing the dependence of the emission intensity of the phosphor on the concentration of the activator when the phosphor of LiSr ₂ Y _0.85 Eu _0.15 O ₄ is excited by ultraviolet rays of 365 nm. In FIG. 6, the vertical axis represents the relative intensity of light emission at the peak wavelength of the light emission wavelength, and the horizontal axis represents the activator concentration of the phosphor.

FIG. 7 is a graph showing the dependence of the emission intensity of the phosphor on the activator concentration when the phosphor of LiSr ₂ Y _0.9 Tb _0.1 O ₄ is excited by ultraviolet rays of 365 nm. The vertical and horizontal axes in FIG. 7 are the same as those in FIG. The dependence of the emission intensity of the phosphor of the present invention on the activator concentration tends to be similar to FIGS. 6 and 7 even when the constituent elements of the phosphor (phosphor composition) are changed. The optimum activator (Ln ′) concentration (x) for obtaining a body is 1 × 10 ⁻⁵ ≦
It is in the range of x ≦ 8 × 10 ⁻¹ , and it has been confirmed that the range of 1 × 10 ⁻³ ≦ x ≦ 5 × 10 ⁻¹ is preferable for obtaining light emission of higher luminance.

The phosphor of the present invention can obtain a phosphor which emits light of an emission color specific to an activator element, particularly when excited by long-wavelength ultraviolet light, and can be used as a fluorescent lamp, a color plasma display, a high-pressure mercury lamp, and the like. It can be used for fluorescent wall materials and tiles for indoor and outdoor wall decoration. In addition, since light is emitted even when excited by an electron beam and an X-ray, it can be widely used for a purpose of emitting light by being excited by an electron beam and an X-ray.

[0024]

[Example 1]

SrCO ₃ 29.5 g Li ₂ CO ₃ 3.7 g Y ₂ O ₃ 9.6 g Eu ₂ O ₃ 2.6 g NH ₄ Cl (flux) 0.9 g The crucible was packed in an alumina crucible, charged in an electric furnace, and fired in air at 800 ° C. for 4 hours. The obtained fired product was pulverized, washed with water, dried and sieved to obtain a phosphor.

This phosphor is made of LiSr ₂ Y _0.85 Eu _0.15
It has a composition of O ₄ and shows the X-ray diffraction diagram shown in FIG.
FIG. 2 shows an emission spectrum when excited by 365 nm ultraviolet light, and its emission peak wavelength was 612 nm.
Red light emission. The excitation spectrum of this phosphor for giving red light emission (612 nm) was as shown in FIG. 4, and the excitation band was extended from the ultraviolet region to the visible region.

[0026] Example 2 _{SrCO 3 29.5 g Li 2 CO 3} 3.7 g Y 2 O 3 10.2 g Tb 4 O 7 1.9 g NH 4 Cl ( flux) 0.9 g The above Were sufficiently mixed, packed in an alumina crucible, charged in an electric furnace, and fired at 1000 ° C. for 4 hours in a carbon reducing atmosphere (CO _x gas atmosphere). The obtained fired product is pulverized,
After washing with water, drying and sieving, a phosphor was obtained.

This phosphor is made of LiSr ₂ Y _0.9 Tb _0.1
FIG. 3 shows an emission spectrum when excited by 365 nm ultraviolet light having a composition of O ₄ and an emission peak wavelength of 5 nm.
It had a yellow-green emission of 52 nm. The excitation spectrum was as shown in FIG. 5, and the main excitation wavelength was in the ultraviolet region of about 320 nm.

[0028]

According to the present invention, by adopting the above-mentioned constitution, in particular, depending on the kind of the rare earth element of the activator added by the excitation of ultraviolet rays, light is emitted mainly from the ultraviolet region to the visible region from blue to red inherent to the rare earth element. A novel phosphor having:

[Brief description of the drawings]

FIG. 1 illustrates a powder X-ray diffraction diagram of a phosphor of Example 1.

FIG. 2 is a graph illustrating an emission spectrum of the phosphor of Example 1.

FIG. 3 is a graph illustrating an emission spectrum of the phosphor of Example 2.

FIG. 4 is a graph illustrating an excitation spectrum of the phosphor of Example 1.

FIG. 5 is a graph illustrating an excitation spectrum of the phosphor of Example 2.

FIG. 6 is a graph illustrating the activator concentration dependency of the emission intensity of the phosphor of Example 1.

FIG. 7 is a graph illustrating the dependence of the emission intensity of the phosphor of Example 2 on the concentration of activator.

Claims (5)

[Claims] 1. A phosphor represented by the following composition formula. _{^{M 1 M 2 2 (Ln,}} Ln ') O 4 ( wherein, M ¹ is Li, a monovalent metal element of one or more selected Na, K, from the group of Rb and Cs, M ² is C
a, Sr, Ba, Be, Mg, Zn, and at least one divalent metal element selected from the group of Cd;
a, Gd and Lu are at least one element selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Tb,
One or more elements selected from the group of Dy, Ho, Er, Tm, and Yb are shown, respectively. ) 2. A phosphor represented by the following composition formula. ^{_{M 1 M 2 2 (Ln 1}} -X, Ln 'X) O 4 ( wherein, M ¹ is Li, Na, K, a monovalent metal element of one or more selected from the group of Rb and Cs, M ² is C
a, Sr, Ba, Be, Mg, Zn, and at least one divalent metal element selected from the group of Cd;
a, Gd and Lu are at least one element selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Tb,
Each represents one or more elements selected from the group consisting of Dy, Ho, Er, Tm, and Yb, and x is 1 × 10 ⁻⁵ ≦ x ≦
This is a number in the range of 8 × 10 ⁻¹ . ) 3. In the above composition formula, x is 1 × 10 ⁻³ ≦ x ≦ 5.
The phosphor according to claim ¹ , wherein the number is in the range of × 10 ⁻¹ . 4. In the above composition formula, M ¹ is Li and M ²
Is Sr and Ln is Y. The phosphor according to claim 1, wherein 5. The composition according to claim 1, wherein the activator Ln ′ of the phosphor is Eu and / or Tb.
5. The phosphor according to any one of items 4 to 4.