JPS6038433B2 - Rare earth oxysulfide phosphor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a Tb (terevitium)-activated rare oxysulfide phosphor, which has particularly high luminous efficiency and low phosphorescence (long afterglow component). Regarding ide compounds.

Tb-activated rare oxysulfide photons emit light efficiently upon X-ray excitation, so they are used for X-ray light surfaces such as intensifying screens, and they It is gradually replacing the crab light body.

In this crab photon, the Tb concentration per 1 mol of the crab photon is 5 x 105 to 3 x 10-2 mol, and in this concentration range, the crab photon becomes a practical crab photon with high luminance. These crab light bodies are also used for the crab light surface of cathode ray tubes and backlight lamps. The present invention was made based on experimental findings that by adding Yb (ytterbium) to a conventional Tb-activated rare oxysulfide phosphor, luminous efficiency was improved and phosphorescence was weakened.

That is, the rare group oxysulfide phosphor of the present invention is represented by the following compositional formula. Ln2(1-p-q)02
The range of S/TQPYb), p, and q is 1×10-4
≦p≦3×10-2, 1×10-6≦q≦0.075p
, where Ln represents at least one of Y, I, W, and Lu.

In particular, the crab photoreceptor of the present invention has excellent properties for use in X-ray intensifying screens. One of the present invention (Y, Gb) 20bu/Tb
, Yb are conventionally used. Brightness is 2.5-3. compared to CaW04. The X-ray absorption rate is approximately 30% higher, and when used as an intensifying screen, it exhibits excellent characteristics of high sensitivity and low quantum noise. These rare ±cervical oxysulfado crab photons are prepared as follows. Dissolve rare species with nitric acid. Add oxalic acid (or dimethyl oxalate) to this solution to obtain dilute oxalate. This is thermally decomposed to form an oxide, and then sulfur powder and K3P04, N and C03 are added as a flux and fired at 1,100 to 130,000. The thus obtained (Y, Gd) 20b/Th, Yb has improved luminous efficiency in the range where Yb is 1 x 10-6 or more and the Tb concentration is 0.07 vowels or less, and the luminous efficiency is improved. The brightness will be improved by about 20%. When the Yb concentration exceeds 0.075 times the Tb concentration, the emission intensity decreases extremely. FIG. 1 is a diagram showing the relationship between Yb concentration and luminescence intensity. Also, the conventional crab light body (Y, Gd) 20
In 2S/Th, a long afterglow (phosphorescence) is observed after X-ray excitation is stopped, but when Yb is added in an amount of 1×10-4 mol'RE or more, the long afterglow decreases by about one order of magnitude. FIG. 2 is a diagram showing this relationship. Almost the same tendency is observed when other rare species are used as the matrix, and the long afterglow component is reduced from a very small amount of Yb of 1 x 10-5 mol'RE. Figure 3 shows La202S,
Gd202S, Y of the Tb-activated crab photoreceptor as the parent body of Y2C
It is a figure showing the sensitization effect by addition of b. By the way, the crab photo substance (Y, 20)/Tb used as the crab photo substance for intensifying screens exhibits strong luminescence in the blue to green region when Tb is around 1 x 10-3 mol/RE, which is different from the conventional one. Displays luminescent characteristics that match the standard film speed used. Sensitivity is CaW0
It is 2.5 to 3 times higher than 4. However, in this Tb concentration range, the long afterglow component after the X-ray excitation stops is strong, resulting in drawbacks such as blurred photographic images and overlapping of previously taken images. However, by using (Y,Gd)202S/Tb,Yb which eliminates the long afterglow component by adding Yb of the present invention, the above-mentioned drawbacks can be solved and the sensitivity of the intensifying screen can be increased by improving the luminous efficiency. In addition, green-emitting photoreceptors La202S/Tb and Gd202S/T° C. were added to increase the luminous intensity and showed excellent characteristics when used in crab light lamps. Furthermore, when used in cathode ray tubes for displays such as oscilloscopes, the current characteristics are greatly improved because brightness saturation due to current density is less than in conventional ZnS matrix backlights. Example 1Y203113 evening, Gd203181 evening, Tb4070.374 evening, YQ
Dissolve 030.0118 in nitric acid.

Add 425 grams of dimethyl oxalate to the mixture, heat to 8,000 ℃, and leave to stand to obtain an oxalate compound. Let this co-order be an oxide fired for 1100 qCI hours. Obtained rare earth oxide 100 sulfur powder to 25 sulfur powder, K3P04
14 Add Na2C0325 and mix.

When this mixture is packed in a Ruzobo and fired at 1200 oo for 4 hours in a nitrogen atmosphere, (Y, Gd). Mother 80bu/mo
．． A crab photon having a composition of 6 on the Yb side of o is obtained. This crab light body has subordinate columns (Y, Gd), . 99802S/Tchi. o
The luminous efficiency was improved by about 20% compared to o2, and the afterglow became weaker as shown in FIG. In addition, the intensifying screen prototyped using this crab photon showed a 25% improvement in sensitivity and a 10% improvement in contrast compared to conventional products.

Example 2 La203326ta Tq072.617# Yb20
330.0079 in the same manner as in Example 1, La, . 9
9 mirror 02S/ThO. o, 4Ybo. Make 2 of oo.

The thus obtained crab luminous material had luminous efficiency improved by about 15% compared to the conventional 202S/Tb. When a crab light lamp was prototyped using this crab light body, the luminous efficiency was improved by 10% compared to the conventionally used edge-colored crab light lamp. Matai 20
This is an improvement of about 18% compared to the crab light lamp using 2S/Tb. Example 3 GQO evening 362.5 ta Tb 4071.495 ta Y
Q030.0079 Example 1 The same aircraft as GdM9202S/ThO. Female Ybo. Create a crab light body named oo.

The crab photons thus obtained are conventional W, . 9920
2S/Tbo. .

The luminous efficiency was improved by about 25% compared to the fake one. Sik using this crab light body. When making an oscilloscope tube, the conventional P-
Compared to No. 31 Crab light surface (ZnS/Cu backlight), the current characteristics were much better, and the brightness was improved by 40% in the high current density region.
Also, Gd,. 99202S/Tb side 30 compared to light side
% brightness improved. Example 4 Y203225.8ta Tb4070.374ta Y
QO's. 395 in the same manner as in Example 1, Y, . $802
S/Tb skin rudder Ybo. o's.

Create the second Kojiko body.

This fin light body is the conventional Y, . 99802S/Tbo. The luminous efficiency was improved by 15% compared to that of

Example 5 L average 033 group TLO? 0.3 tablet paper Yb2030
．． Lu...980 on the evening of 0118 with the same aircraft as Example 1
2S/ThO. Side Ybo. Create a crab light body called 6 on the o side.

This crab light body is subordinate to Lu, . 9Kyou02S/Tho. oo
The luminous efficiency was improved by 20% compared to 2. As described in the examples above, the present invention improves the luminous efficiency of the conventional rare earth oxysulfide photomaterial activated with Tb by several tens of percent, and when excited with conventional X-rays (Y, Gd) 202S /Td etc. was able to eliminate the afterglow component.

These light beams can be used in X-ray light surfaces, cathode ray tube rear light surfaces, and full-body light lamps to improve efficiency compared to conventional ones.

[Brief explanation of the drawings] Figure 1 shows (Y, Gb)...Sasa○ko/T Hiroshi. Figure 2 showing the change in luminous efficiency when Yb is added to the oo2 phosphor.
The figure shows the change in afterglow intensity over time when Yb is added to this crab photon.
FIG. 2 is a diagram showing changes in luminous efficiency due to addition of Yb to each base material of 2S. Figure 1 Figure 2 Figure 3

Claims (1)

[Scope of Claims] 1. A Tb-activated rare earth oxysulfide phosphor represented by the following compositional formula. Ln_2(1-p-q)O_2S/Tb_2pYb_2
q However, the range of p and q is 1×10^-^4≦p≦3
×10^-^2, 1×10^-^6≦q≦0.075p
, where Ln represents at least one of Y, La, Gd, and Lu.