JPH08325566A - Zinc sulfide phosphor - Google Patents

Abstract

PURPOSE: To obtain a high-luminance phosphor capable of attaining sufficiently high luminance without the aid of high-density electron beam irradiation, thus useful as an orange phosphor. CONSTITUTION: This phoshor is a Mn-activated ZnS phosphor represented by the composition formula ZnS:Mn, wherein, when the half-value width of<67> Zn signal in the proximity of 380ppm (Δν1/2 (Zn)) determined by static NMP is plotted in relation to the Mn concentration, and the half-value width of<67> Zn signal in the proximity of 380ppm (Δν1/2 (Zn)ST) determined by static NMR is plotted in relation to the Mn concentration of a ZnS:Mn phosphor as the standard, the relationship: Δν2 (Mn)>Δν1/2 (Mn)ST is satisfied where the above two kinds of Mn concentrations are identical.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zinc sulfide phosphor, and more particularly to a zinc sulfide phosphor used for a thin film EL plate or the like which exhibits high brightness characteristics when excited by an electron beam.

[0002]

2. Description of the Related Art M as an activator represented by ZnS: Mn
The Mn-activated ZnS phosphor to which n is added exhibits bright orange fluorescence and is used for a thin film EL plate and the like. The market needs for phosphors are strongly desired to be finer and brighter as the size and quality of video equipment such as projection large-screen televisions and high-definition televisions increase. In order to display a high-definition image on a large screen, a high-density electron beam is made incident. However, when the current density is increased with ZnS phosphor, the luminous efficiency of the phosphor decreases with the passage of time. Therefore, the brightness is not sufficient to obtain a high-density screen, and a ZnS phosphor with higher brightness is required.

[0003]

[Problems to be Solved by the Invention] Under these circumstances,
There was a need for ZnS phosphors with higher brightness characteristics at low current densities. The present invention provides a ZnS phosphor that maintains high-definition and high-luminance brightness on a thin film EL plate without increasing the intensity of an incident electron beam.

[0004]

In order to achieve the above object, the inventors of the present invention have sufficiently studied the existence state and distribution state of Mn, which is the emission center of Mn-activated ZnS phosphor, and the structure of the phosphor crystal. As a result, they have found that a ZnS phosphor having a specific NMR (nuclear magnetic resonance) characteristic has a high brightness characteristic, and arrived at the present invention.

The gist of the present invention is a Mn-activated ZnS phosphor represented by ZnS: Mn, which has a full width at half maximum (Δν) of ⁶⁷ Zn signal in the vicinity of 380 ppm by static NMR.
_1/2 (Zn)) is plotted against Mn concentration, and the standard Mn concentration of ZnS: Mn phosphor and static NM
When the full width at half maximum of the ⁶⁷ Zn signal (Δν _1/2 (Zn) ^ST ) near 380 ppm by R is plotted, Δν _1/2 (Mn)> Δν _1/2 (Mn) ^ST at the same Mn concentration. It is a zinc sulfide phosphor characterized by.

The present invention uses 38 by static NMR.
The line width of the ⁶⁷ Zn signal near 0 ppm is linearly proportional to the Mn concentration, and when the Mn concentration is constant,
^This is based on the fact that the larger the line width of the ⁶⁷ Zn signal, the higher the brightness that can be achieved. Although the scientific elucidation of this has not been done so far, the line width broadening of the ⁶⁷ Zn signal peak near 380 ppm was found to be Mn ²⁺ (3d ⁵ ).
Is caused by the paramagnetic relaxation of Zn ²⁺
It is considered that the difference in the distribution of Mn is reflected in the ZnS crystal substituted with n ²⁺ .

The phosphor of the present invention is a Mn-activated ZnS phosphor represented by ZnS: Mn, and the addition amount of Mn as an activator is usually 10 mol% or less, preferably 1 to 7 mol%.
Is. Around 380 ppm by static NMR
The broadening of the signal line width of ⁶⁷ Zn is represented by the full width at half maximum (Δν _1/2 (Zn)) of the signal peak, and the resonance frequency is 18.8 M by NMR using a static probe.
Hz, pulse width 5 μsec (30 ° pulse), waiting time 2.5 sec, and integration time are usually obtained by measuring 1000 to 2000 times. From the linearity of the signal,
The line width is obtained by separating the linear shape using a Gaussian function by the usual method. The full width at half maximum is plotted on the vertical axis, and the Mn concentration is plotted on the horizontal axis.

Next, a standard line is created. First, Zn
A standard substance of S: Mn is prepared. After thoroughly mixing ZnS and manganese carbonate in an amount corresponding to each concentration, the mixture is filled in a quartz crucible and baked at 900 ° C. for 75 minutes. The fired product obtained is thoroughly washed with pure water, dried at 120 ° C. and sieved to obtain a ZnS: Mn standard substance.

Using the same standard material as above, a ⁶⁷ Zn signal near 380 ppm was obtained by static NMR, and the half-value width (Δν _1/2 (Zn) ^ST ) was determined. Similarly to the above, the half-value width is plotted on the vertical axis, and the Mn concentration is plotted on the horizontal axis.

The phosphor of the present invention has the same Mn concentration and is larger than the full width at half maximum of the standard ZnS: Mn phosphor. That is, Δν _1/2 (Mn)> Δν _1/2 (Mn) ^ST . In particular, Δν _1/2 (Mn)> Δν _1/2 (Mn) ^ST +
50 Hz is preferable, and Δν _1/2 (Mn)> Δν
_1/2 (Mn) ^ST +100 Hz is preferable.

The phosphor of the present invention can be preferably produced, for example, by the following method. First, raw material ZnS and manganese carbonate are mixed well in a desired composition, and the mixture is baked at a temperature of 700 ° C. to 980 ° C. for 30 minutes or more. 120 after washing the obtained baked product with water
Obtained by drying at ℃. Even in the case of such a process or other manufacturing method, a calibration curve with a standard substance should be prepared in advance, and the half-value width of the obtained phosphor should be monitored to adjust the amount of activator and each treatment condition. It can also be manufactured in.

[0012]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. ^{The full} width at half maximum of the ⁶⁷ Zn signal (Δν _1/2 (Zn), Δν _1/2 (Zn) ^ST ) was measured by mounting a static probe on a solid NMR apparatus MSL-300 manufactured by Bruker. The measurement conditions are as follows.

[0013]

[Table 1] Probe: Static probe Resonance frequency: 18.8 MHz Pulse sequence: Single pulse Pulse width: 5 μsec (30 ° pulse) Wait time: 2.5 sec

Hereinafter, the Mn concentration and the impurity concentration of each sample are as follows: Seiko SPS-1200AICP device (inductively coupled high frequency plasma emission spectrometer) and Rigaku33.
Quantification was performed using a 70 fluorescent X-ray apparatus. In addition, the measurement of the brightness of the phosphor is performed by an electron beam excitation device (TOPCON ABT-
32).

Reference Examples 1 to 6 (Preparation of Standard Material) Raw material Z having the composition shown in Table 1 below.
nS and manganese carbonate were thoroughly mixed by a dry method, filled in a crucible made of quartz, and baked at a temperature of 900 ° C. for 75 minutes. The obtained fired product was sufficiently washed with pure water, dried at 120 ° C., and sieved to obtain a ZnS: Mn standard substance. As a result of powder X-ray diffraction, all were ZnS. In addition, the amount of Zn / Mn was the same as the charged amount within the range of experimental error by the ICP apparatus. In addition, the signal shapes of the emission spectra were almost the same in Reference Examples 2 to 6. When these phosphors were excited with an electron beam, all of them glowed orange except for Reference Example 1.

[0016]

[Table 2]

(Preparation of standard line of full width at half maximum of ⁶⁷ Zn signal) For the standard substances of Reference Examples 1 to 6, static N
Full width at half maximum of ⁶⁷ Zn signal (Δν _1/2 (Z
n) ^ST ) was measured and calculated. ^{The full} width at half maximum of the ⁶⁷ Zn signal (Δν _1/2 (Zn) ^ST ) is shown in Table 1 together with the Mn concentration. Also, based on this, the standard line obtained by plotting the relationship by plotting the full width at half maximum of the ⁶⁷ Zn signal (Δν _1/2 (Zn) ^ST ) on the vertical axis and the Mn concentration on the horizontal axis, As shown in FIG.

(Example 1) ZnS 100.00 g, M
After 2.42 g of nCO ₃ .H ₂ O was thoroughly mixed by a dry method, the mixture was charged into a quartz crucible and baked at a temperature of 980 ° C. for 75 minutes. After thoroughly washing the obtained baked product with pure water,
It was dried at 120 ° C. and sieved. The obtained phosphor is Zn
It is represented by S: Mn.

(Example 2) ZnS: M was prepared in the same manner as in Example 1 except that the firing time was changed to 150 minutes.
An n phosphor was obtained. This was confirmed by static NMR ⁶⁷
The full width at half maximum of the Zn signal (Δν _1/2 (Zn)) was measured. The NMR chart is shown in FIG. Then the brightness was measured. Table 2 shows the results.

(Comparative Example 1) ZnS: M was prepared in the same manner as in Example 1 except that the firing temperature was changed to 700 ° C.
An n phosphor was obtained. This was confirmed by static NMR ⁶⁷
The full width at half maximum of the Zn signal (Δν _1/2 (Zn)) was measured. Then the brightness was measured. Table 2 shows the results.

Comparative Example 2 ZnS: Mn was prepared in the same manner as in Example 1 except that the firing time was changed to 30 minutes.
A phosphor was obtained. ⁶⁷ Z by static NMR
The half-width of the n signal (Δν _1/2 (Zn)) was measured.
Then the brightness was measured. Table 2 shows the results.

Example 3 ZnS 100.00 g, M
After 3.63 g of nCO ₃ .H ₂ O was thoroughly mixed by a dry method, the mixture was charged into a quartz crucible and baked at a temperature of 980 ° C. for 75 minutes. After thoroughly washing the obtained baked product with pure water,
It was dried at 120 ° C. and sieved. The obtained phosphor is Zn
It is represented by S: Mn. The full width at half maximum of the ⁶⁷ Zn signal (Δν _1/2 (Zn)) was measured by static NMR. Then the brightness was measured. Table 2 shows the results.

(Comparative Example 3) ZnS: M was prepared in the same manner as in Example 3 except that the firing temperature was changed to 800 ° C.
An n phosphor was obtained. This was confirmed by static NMR ⁶⁷
The full width at half maximum of the Zn signal (Δν _1/2 (Zn)) was measured. Then the brightness was measured. Table 2 shows the results.

[0024]

[Table 3]

The full width at half maximum of the ⁶⁷ Zn signal in Table 3 (Δν _1/2
( ⁶⁷ Zn)) is plotted on the vertical axis and Mn concentration is plotted on the horizontal axis. The relationship is plotted, and the relationship with the standard line of FIG. As is apparent from FIG. 1, those of the examples of the present invention having excellent relative brightness have half-width values higher than the standard line.

[0026]

INDUSTRIAL APPLICABILITY The phosphor of the present invention has high brightness and can achieve sufficiently high brightness without being irradiated with a high-density electron beam, and is useful as an orange phosphor.

[Brief description of drawings]

FIG. 1 is a full width at half maximum of a ⁶⁷ Zn signal of the phosphor of the present invention (Δ
The graph which showed the relationship of (nu) _1/2 (Zn)) and Mn concentration, and the relationship with a standard line.

FIG. 2 Full width at half maximum of ⁶⁷ Zn signal of standard substance (Δν _1/2
The graph which shows the relationship between (Mn) ^ST ) and Mn concentration.

FIG. 3 is an NMR chart of the ZnS: Mn phosphor of Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryuji Adachi 1060 Narita, Odawara-shi, Kanagawa Kasei Optonix Co., Ltd. Odawara Plant (72) Inventor, Hase Ko, 1060 Narita, Odawara-shi, Kanagawa Odawara Plant Within

Claims (1)

[Claims] 1. A Mn-activated ZnS represented by ZnS: Mn.
Phosphor, 380 pp by static NMR
FWHM of ⁶⁷ Zn signal near m (Δν _1/2 (Zn))
Is plotted against Mn concentration, and standard ZnS: M
Mn concentration of n phosphor and 380 by static NMR
Full width at half maximum of ⁶⁷ Zn signal in the vicinity of ppm (Δν _1/2 (Z
n) When ^ST ) is plotted, at the same Mn concentration, Δν _1/2
A zinc sulfide phosphor characterized in that (Mn)> Δν _1/2 (Mn) ^ST .