JPS6015485A - Green color phosphorescent material - Google Patents

Abstract

PURPOSE:To provide a green color phosphorescent material exhibiting improved luminance under excitation with a low velocity electron beam, prepd. by mixing an electrically conductive metal oxide having a specified particle size distribution with a terbium-activated rare earth oxide/sulfide phosphor. CONSTITUTION:The green color phosphorescent material is prepd. by mixing (A) at least one electrically conductive metal oxide having a particle size distribution of 0.1-2.4mu in median and 0.7 or lower in standard deviation (e.g. In2O3, SnO2 and ZnO) with (B) at least one terbium-activated rare earth oxide/sulfide phosphor shown by formula, R2O2S:Tb (where R is one or more of Y, Gd and La) in a blend ratio of 14:1 to 1:14 by weight. Component (B) is obtained, e.g., by adding sulfur and sodium carbonate as flux to a mixt. of La2O3, Y2O3 in a given molar ratio and burning it at about 1,200-1,300 deg.C in the air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a phosphor for slow electron beams that emits green light. More specifically, a low-speed electron beam prepared by mixing an appropriate amount of at least one conductive metal oxide (I2O3,5LIO7ZnO) having a specific particle size distribution of the present invention and at least one specific green phosphor. Regarding phosphors for use.

Conventionally, indium oxide (■,.

0,) and terbium-activated late yttrium sulfide phosphor (:
A luminescent composition prepared by mixing Y2O, S: Tb) at an M amount ratio of 29 to 9:1,
) and Y, 02S:Tb in a weight ratio of 1=9 to 9:1 are known. These light-emitting compositions exhibit green light emission under slow electron beam excitation at an accelerating voltage of I KVV or lower, particularly 100 V or lower, but from a practical standpoint, it is desired to further improve the luminescence by 14 degrees.

An object of the present invention is to provide a green light-emitting composition with improved emission brightness under slow electron beam excitation at an accelerating voltage of IK, V or less, particularly, tooy or less.

The inventors of the present invention have conducted extensive research in order to improve the luminance of the above-mentioned conventionally known green light-emitting compositions.

As a result, it was found that the luminance was improved when using appropriate amounts of In2O, 6-C, and ZnO with a specific particle size distribution.
``C source composition 11.
02), tungsten oxide (WO3), niobium oxide (N
2o2s:TbCHowever, Y
,, Is it possible to get the same effect as above even if Gd D and La's 1 or 2 yen v, upper) V gets stuck? To Kuzu who completes "Mita Shihonbatsu 9", J/"C.

1. Use as a conductive substance that is a component of the luminescent composition of the present invention.
Q r) The exclusive metal acid that can be used is ■. 203,
ZnO18nO2, rI02, WO8, INb2O6, etc.: 8+Nigeraj.

Ru. In particular, from the viewpoint of luminance of the composition obtained, I n20
8.8 nO2 and ZnO are more preferred. In addition, In
20B and S. 02, when the green-emitting phosphor is the same, the luminance of the composition using In2O is generally higher than that of the composition using 8,102 when the applied a storm pressure is 60V or less. is sick, acceleration voltage is 60V xp
The opposite is true if the value is also high.

These conductive metal oxides have a median value of 0. ]~2.4μ,
Those having a particle size distribution with a standard deviation value of 0.7 or less are used. The median value is outside the above range, and the standard deviation value is 0.
．． Those having a particle size distribution larger than 7p are not used because the luminance of the resulting composition is low.

The more preferable median range varies depending on the type of green-emitting phosphor to be mixed with the conductive material, but is generally 3 to 1.
It is 0μ. Further, when the median value is constant, the standard deviation value is preferably as small as possible, and is generally preferably dO15 or less.

Conductive metal oxides having the above particle size distribution can be produced by directly firing a general reagent or a fired product obtained by firing a general reagent in air, a neutral atmosphere, or a weakly reducing atmosphere. It is obtained by crushing with a ball mill, roll mill, etc. and then classifying it. Alternatively, compounds that can be easily converted into metal oxides by a heat source such as carbonates, oxalates, hydroxides, etc. may be calcined in air to obtain metal oxides, and the metal oxides may be classified. The reason for using a fired product is that the temperature stability of the fired product is better than that of raw powder that is not fired, and therefore, the luminescence is better when a fired product is used than when raw powder is used. A composition 1c with good stability can be obtained. In addition, R2, which is the other component of the luminescent material,
02S: Tb r Namely, lanthanum oxide (LR20s) and yttrium oxide (Y20s)
g) and L820syjτ1 for Y2O3x moles
-x) mole, and then add and mix a predetermined amount of terbium oxide (Tb20g) to the mixed rare earth oxide, which is obtained by adding 20 to 40% by weight of sulfur (sl and 20 to 40% as a flux). Added 40% by weight of sodium carbonate (N a 2 CO 3 ) in the air.
200'C-1300'Cf Obtained by firing for 1 to 5 hours Note that L at Us , Y2
To obtain a mixed rare earth consisting of 20 g of Tb and 20 g of Tb, it is possible to simply mix them physically, but generally, in order to improve the mixability, they are first dissolved in a mineral acid such as nitric acid or hydrochloric acid. , by adding an oxalic acid aqueous solution to this
1 Lanthanum sulfate? (A method has been adopted in which yttrium zate and terbium oxalate are co-precipitated, and the co-precipitated rare earth l15 acid salt is heated to form a mixed rare earth oxide. The amount of activator Tb is 10.9 to 1.5x with respect to the base material It, 2t)2Sl, 9.
It's xo'7 and it's good size 5xioy~6X10,
It is 9. In addition, if the temperature is -44 (in other words, terbium-activated acid (flt-formed Laflanthanum phosphor L -20□
8:Tb), it goes without saying that the 11 combination of Y2O3 in the above-mentioned manufacturing method is unnecessary. These phosphors generally have a particle size distribution with a median value of 1 to 20 microns and a standard deviation value of 0.7 or less. In the present invention, the median value of C is preferably 3μ to 10μ.
belongs to. Among these fluorescent materials, Y2O2S:Tb fluorescent material is particularly preferred from the viewpoint of luminance of the resulting composition.

The luminescent composition of the present invention can be obtained by combining the above-mentioned conductive substance and green luminescent phosphor in a mortar, ball mill, mixer mill, or the like. Both materials are mixed in an M amount ratio such that the value of the conductive substance/green emitting phosphor is 1/14 to 14/1, and when the value of the conductive substance is less than 1/14, charge-up by the magnetically conductive substance is prevented. No effect is obtained and the composition therefore has properties close to those of a green-emitting phosphor and does not emit light under slow electron beam excitation. On the other hand, when the value of longitudinal conductive material/green emitting phosphor is larger than 14/1, the resulting composition emits very weak light. Although the effect of preventing Ciq↓−↓ is sufficient, it is thought that this is because the light emission from the phosphor is blocked by the concentrated substance.

The light-emitting composition obtained by the present invention is set in a low-speed electron beam excitation device 1 as shown in FIG. This makes it possible to emit light with sufficient clarity using the low-velocity Nariko beam.

Figure 2 shows "ntos (!: 'Y2O2S :'Tb
The graph shows the relationship between the n2o content (M amount %) and the luminescence degree of the composition in the luminescent composition containing phosphor 826. Curves a, t) and C are the standard deviation values, respectively. are all 0.4, but the median value is 0.3μ.
, 0.6 μ, 1.5 μ. This is the case when 20s is used.

In addition, in FIG. 2, the luminance (slope IIIl) is curve C.
It is expressed as a cutting value with a maximum luminous species degree of 100.

As is clear from FIG. 2, 1n20. The median value of is small B
The more you get, the more you need to obtain the maximum luminance. ,
0. The content will be less. In other words, if the median value is small, 1n
2 (J3 is used, the median is larger -, Lo J
IU↓ Lo20. There is also less damage when using . High-intensity light emission can be obtained with a 2o3 content. 1. As is clear from FIG. 2, when comparing the maximum luminance at each median value, the maximum luminance is the best when the median value of In2O3 is 0.6 μ.

Figure 3 is the same as Figure 2 +n, U3 and Yz02S:Tb
FIG. 3 is a graph showing the relationship between the median value of 1n2u3 and the maximum luminance of the composition when the standard deviation is constant (gu (1,4)) in a luminescent composition mixed with a phosphor. The maximum luminance (vertical axis) has a median value of 1.5.
II + 2 (expressed as a relative value with the maximum luminance of the composition using L13 as 100%). I see that the maximum luminance has improved and is approximately 0.
．． The maximum brightness is reached at 6μ, but as the median value becomes even smaller, the maximum brightness tends to decrease. General reagents 1.
20. usually has a median value of 20μ to 30μ,
1n20 of this general reagent. Considering the luminescence brightness of the luminescent composition using as a standard, the median value is 0.1-2.4μ
It can be seen that a luminescent composition with improved luminance can be obtained when 1203 is selectively used, especially when 1.20. When used, a composition with significantly improved luminance can be produced.

Note that the standard deviation value also affects the luminance of the composition. That is, within the median value range of 0.1 to 2.4μ, the luminance tends to decrease as the standard deviation value increases. This is because the larger the standard deviation value is, the more large particles and small particles that have a low contribution to luminance are included. From this point, the standard deviation value is determined to be 0.7 or less. Good luck r
i O,s or less.

In addition, Figures 2 and 3 are ■・1203 and Y20□s:'
The same trends as in FIGS. 2 and 3 were obtained when other green phosphors were used instead of the r'b or Y202 S:'l"b phosphors.The luminescent composition of the present invention , the conductive metal oxide is limited to having a particle size distribution with a median value of 0.1 μ to 244 μ and a standard deviation value of 0.7 or less,
Also, the mixing weight ratio of the conductive material and the green phosphor was 14/1.
The limitation to 1/14 was based on the above-mentioned findings.

As mentioned above, the present invention has an acceleration voltage of 1 or less, especially 1
The present invention provides a primary color generating composition with improved luminance under slow electron beam excitation of 0.0 V or less, and has great industrial utility value.

Next, the present invention will be explained by examples.

Example 1 Engineering n20. The reagent was dissolved and ammonia water was added to precipitate the hydroxide, which was washed with water, filtered and dried, then calcined in the air at 1200°C for 1 hour, crushed, and then classified, with a median value of 1.5.
Inx having a particle size distribution with a μ standard deviation value of 0.4
(J35.li' and Y2 with a particle size distribution with a median value of 6μ and a standard deviation value of 0.35 manufactured by a normal manufacturing method)
After thoroughly mixing 5 g of O2S:Tb phosphor using a mortar, 30 m9 of the mixture was taken and placed in the apparatus shown in FIG. The mounting was carried out by placing the composition 5 on the anode 6 on the insulating substrate 7 placed in the vacuum chamber 1. After evacuating the inside of this device to 1×10 Torr or less, the oxide-coated filament 2 is activated, and thermionic electrons 3 are generated with a filament current of 0.09 mA, and the grid 4 is
When a voltage of θ~150cm was applied between the anode 6 and the anode 6, 1
Green light emission was observed from around 5V, 120F at 30V
A brightness of t −L was obtained.

Example 2 Classify 1,,O, created in the same manner as Example 1,
In2053g having a particle size distribution with a median value of 0.6 μ and a standard deviation of 0.4 and Y2O2S:Tb, which is the same as in Example 1.
7 g of fluorescens was mixed in a mortar. When the obtained composition was excited with a slow electron beam in the same manner as in Example 1, green light emission was observed from around 15■ and 150F+ at 30V.
-L luminance was obtained.

Example 3 8n02 produced in the same manner as in Example 1 was classified to obtain S having a particle size distribution with a median value of 0.5μ and a standard deviation of 0.4.
n lJ23 l and the same y, o, s:'rb as in Example 1
Fluorescent material 7II was mixed using a mortar. When the obtained composition was excited with a slow electron beam in the same manner as in Example 1, blue light emission was observed from around 18V and 145F at 30V.
A brightness of t-L was obtained.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a demau/tuple device for excitation with slow electron beams, in which 1 vacuum chamber, 2 a cathode, 3 irradiation electrons, 4
5 is a grid, 5 is a light emitting material, 6 is an anode, and 71d is an insulating substrate. Figure 2 is a diagram showing the luminance luminance versus the mixing weight ratio of In,
2 is a graph showing the relationship between the median value of In2O and the maximum luminance of the composition when the standard deviation is kept constant in a luminescent composition in which YzoJS:Tb phosphor is mixed with YzoJS:Tb phosphor. 〕 1 l AC

Claims (2)

[Claims] (1) At least one conductive metal oxide (I++20s, 5n02.Zn0) having a particle size distribution with a median value of 0.1 tt to 2.4 μ standard deviation Ck)gF) of 0.7 or less. and at least one of the terbium-activated rare earth #1 sulfide phosphors having the general formula R202S:Tb (wherein R is 1m or more of Y, Gd, and La) in a ratio of 14:1 to ]:14
A green luminescent material mixed in a weight ratio of . (2) The green light-emitting material 0 according to claim 1, characterized in that the median value of the phosphor is 3 μ to 10 μ.