JPS5869281A - Oxyhalide phosphor - Google Patents

Abstract

NEW MATERIAL:Compounds of the formula wherein MIII is at least one trivalent metal selected from Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb and Bi; X is Cl and/or Br; x is a number satisfying the condition of 0<x<0.1. USE:Ce-activated trivalent metal oxyhalide phosphors which is suitable for use in a radiation image conversion method utilizing stimulation emission and X-ray sensitized paper, and instantaneously emits blue light under the excitation of X- rays, electron beam, ultraviolet light, etc. PREPARATION:A trivalent metal oxide of the formula MIII2O3 is thoroughly mixed with a starting material for a phosphor, consisting of NH4Cl and/or NH4Br and CeO2. The mixture is pre-calcined in a weakly reducing atmosphere at 400-800 deg.C for 1-6hr and then calcined at 800-1,300 deg.C for 1-6hr.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to oxyhalide phosphors, and more particularly to cerium-attached ff1J valent metal oxynolide phosphors.

Conventionally, as /II of oxyhalide phosphor, its #i
The i formula is LnOX:xCe (Ln is at least one trivalent metal selected from the group consisting of La, Gd, l, u, and Y, and X is one of α and Br or one of them) A cerium-activated trivalent metal oxyhalide phosphor is known, where X is 0 (X (0, / condition ta plus number). It is used as a phosphor for X-ray intensifying screens because it emits blue light (instantaneous light emission) when excited with F, such as electron-1 ultraviolet fiber, and its emission spectrum matches the spectral sensitivity of regular type XII photographic film. It is useful.

The cerium-activated trivalent metal oxyhalide phosphor is a photostimulable phosphor (a phosphor that emits light when excited with electromagnetic waves selected from visible light and infrared light after being irradiated with radiation. Radiation includes X-rays, alpha rays, beta beams, rfII&, high-energy neutron beams, electron beams, vacuum cables, ultraviolet l11
81 magnitude electromagnetic waves or particles. ), and therefore it is known that it can be used in a radiation image conversion method using a photostimulable phosphor. That is, the radiation that has passed through the object is absorbed by the Oxy-Raid phosphor, and then this phosphor is excited with electromagnetic waves selected from long-wavelength light of pjOnm or higher and infrared rays. It is possible to image radiation by emitting the accumulated radiation energy as fluorescent light and detecting this fluorescent light with a photoelectric conversion device such as a 7-otomultiplier tube (Japanese Patent Application Laid-open No. 11-11121) Kol Sanhiro issue, same j4-110JI
No., JJ-/l group J No. 0).

The trivalent metal constituting the matrix of the cerium-activated trivalent metal oxy/＼ride phosphor is made of at least i@ of Ll, Gd, Lu, and Y. A cerium-attached 2J-valent metal oxyhalide phosphor made of a metal other than metal on this fabric has not been known at all.

An object of the present invention is to provide a novel cerium-sealed J-valent metal oxyhalide fluoride body in which the trivalent metal constituting the matrix is a metal other than the above-mentioned cloth steel metal. Another object of the present invention is to produce a cerium-activated j-valent metal oxyno-
Provides a ride phosphor.

In order to achieve the above object, the present inventors have been searching for trivalent metal oxyhalides that can be activated by cerium. As a result, the 1lla tribe/tanoid pr
, Nd, Pm, Sm, Eu.

Tb, Dy, Ho, Er, Tm and HiYI), Oyobiv
Oxyhalide of a trivalent metal of at least lfs selected from the group consisting of Bi, a group B metal (however, halogen is α
and Br) as a matrix, and when this matrix is activated with cerium, a phosphor that exhibits W-color instantaneous and stimulated luminescence can be obtained. This discovery led to the completion of the present invention.

The compositional formula of the cerium-activated trivalent gold-oxy7-ride phosphor of the present invention is M"OX:XCe (where M is Pr, Nd, Pm, am, or Eu.

'l'b, l) y, ) (o, , gr, Tm, Yb ojhi B1 with at least l lumber J @ gold metal, X is either α and f3r or both, and X is expressed as 0 (a number that satisfies the conditions x (θ, l). Shows instant evening light emission.

Further, after this phosphor is irradiated with radiation such as X-rays, ≠j0 to ooom, preferably pjo to yz.

When excited with electromagnetic waves in the nm wavelength range, it exhibits w-color stimulated luminescence.

The present invention will be explained in detail below.

The cerium-activated J-valent metal oxyride phosphor of the present invention represented by the above compositional formula is manufactured by the manufacturing method described below.

First, the raw materials for the phosphor are 1) Pr, 0. , Nd, 0. , Pm, 0. , SmOEu
UTb4O7, 23% 23% DYOHoOErzOa, 23% 23% Tm0YbO and Bi2O5 Spirit 3-23 at least l of 1) NH4 (j and 0NH4BY (D of which one or both, and 11i) Ce02 The oxide of I) and the cerium oxide of 11) are stoichiometrically at least one trivalent metal selected from the group consisting of Bi, where X is Ox O is used in the amount necessary to obtain the mixed oxide represented by (a number that satisfies the condition: (approximately 2.2 times the stoichiometrically required charge).

The required amount of each of the phosphor raw materials of the above apparatus), ii) and 111) is weighed out and thoroughly mixed. Next, the obtained phosphor raw material mixture is filled into a heat-resistant container such as a quartz boat, an alumina crucible, or a quartz crucible, and fired in an electric furnace. This firing consists of pre-firing and main firing. That is, first, the phosphor raw material mixture is fired at a temperature of -00 to 1000C for 1 to 4 hours. By this firing, ammonium halogenide in the phosphor raw material mixture is decomposed and hydrogen halide (
Hct or HBr or H (j and HHr) is vaporized into ammonia (NH,), and a part of the hydrogen oxide reacts with the oxide of 1) above to form trivalent metal oxyhalide (M”OX). ) is generated.Next, the firing tIIA degree is increased and main firing is performed.This main firing is 100~IJOO@
The reaction is carried out at a temperature of 1 to 1 hour. In both the pre-firing and the main firing, a mono-reducing atmosphere such as an ii1 cumulative gas atmosphere containing a small amount of hydrogen gas or a coal-board gas atmosphere containing a small amount of carbon monoxide is used as the firing atmosphere. After firing,
The phosphor of the present invention is obtained by loosening the obtained fired product and sieving it by a valley-pole operation commonly employed in the production of phosphors.

The cerium-activated Jihi gold-oxyhalide phosphor of the present invention manufactured by the above-described manufacturing method has a composition formula of MOX, xCe (where Mll is Pr, Nd, pm, am, or 1eu).

Tb, 'Dy, HoXEr, 'I'm, yb and Bi
, at least 111 trivalent metals selected from the group j, X is one or both of α and Br, and X is a number satisfying the condition 0 x Oll. It is expressed as This phosphor exhibits instantaneous blue light emission ft, ir under excitation with X111il, electron beam, ultraviolet, etc.

The emission spectrum of the phosphor of the present invention matches the spectral sensitivity of regular type X-ray photographic film, and also matches the spectral sensitivity of photoelectric conversion devices such as photomultiplier tubes. It is particularly useful as a phosphor for X-edge intensifying screens and as a phosphor for use in radiation image conversion methods that utilize stimulated luminescence.

Figure 1 illustrates the emission spectrum of the phosphor of the present invention, and is the emission spectrum due to X@ excitation of the Nd0Br, toCe phosphor. As is clear from FIG. 1, Nd0Br,t.

The Ce phosphor emits blue light under X1iA excitation, and its emission spectrum matches the spectral sensitivity of regular type X-Yoma film.

Note that the #I1 diagram shows the emission spectrum due to X-excitation, but the emission spectrum due to excitation by electron beams, ultraviolet, etc.
It is almost the same as the figure. Also @/The figure is NdUBr:io”
Although this is the emission spectrum of the Ce phosphor, the emission spectra of other phosphors of the present invention that differ from either or both of the trivalent metal (Nd) and halogen (Br) as the host constituents are also shown in the g1 diagram. Almost the same. Of course, in the emission spectrum of the phosphor of the present invention, the position of the emission peak does not change even if the cerium-coated oil amount X value changes.

As mentioned above, the phosphor of the present invention emits instantaneous blue light when excited by X-rays, electron beams, ultraviolet rays, etc.; UZO no Torioo
It exhibits blue stimulated luminescence when excited with electromagnetic radiation in the nm wavelength range. Therefore, the phosphor of the present invention is the above-mentioned photostimulable phosphor t1.
The III-exhaustible fluorescent phosphor used in the radiation one-image conversion method is useful.

That is, the radiation transmitted through the object is absorbed by the phosphor of the present invention, and then the phosphor is
The radiation accumulated in the phosphor by electromagnetic waves in the growth region of m is excited, and the radiation accumulated in the phosphor is emitted as fluorescence, and by detecting the fluorescence of O, the radiation 1w image l[1IIoI!
The change is the key.

Figure 2 shows the intensity of the fluorescent light emitted from the JOt'Jd (JBr, /OCe phosphor) when the phosphor is excited with electromagnetic waves of different wavelengths after being irradiated with XftM. If
The one showing the f-oxidation (i.e., the photostimulated excitation spectrum) is shown. As is clear from Fig. 44, after receiving the Nd0Br, 10Ce phosphor
It exhibits stimulated luminescence when excited by electromagnetic waves of Onm wavelength chain acids. The color of the light emitted from the Nd0Br, 10Ce phosphor due to stimulation is evening, and the stimulated emission spectrum of the phosphor is almost the same as that shown in FIG. Figure 2 shows Nd0Br
: This is the cvH exhaustion excitation spectrum of the to-3ce phosphor, but the excitation spectrum of other phosphors of the present invention in which either or both of the trivalent metal (Nd) and halogen (Bi), which are the host constituents, is different is shown. The excitation spectrum is also almost the same as in FIG.

A case in which the phosphor of the present invention is used in a radiation-image conversion method using stimulated luminescence will be specifically explained using schematic diagrams. Third
In the figure //Fi is the radiation-generating device, lj is the object,
IJ is a radiation fl conversion panel having a photostimulable phosphor layer containing the cerium-activated trivalent metal oxyhalide phosphor of the present invention; )≠ is the radiation accumulated in the radiation-image conversion panel;
11 is a light source as an excitation source for emitting the m image as fluorescence, lj is an optical I#IL conversion device that detects the fluorescence emitted from the skeleton radiation & fl conversion panel, and 11 is a photoelectric conversion device (' A device that reproduces the l! No. as an m image, /7 a device that displays the reproduced m image, /I a light f:lAl+
The reflected light from L is cut and the radiation 1W image conversion panel 13
This is a filter that allows only the most emitted light to pass through. /j to r1# may be anything that can reproduce the light extinction @ from 13 as an image in some form, and is not limited to the above.

As shown in Figure 3, the plate donor l is radiated - the generation value F
When radiation is placed between jkli and the radiation*image conversion panel 13 and irradiated with radiation, the radiation is transmitted according to changes in the radiation transmittance of each part of the subject lλ, and the transmitted image (that is, the image of the intensity of the radiation) is The radiation enters the radiation-image conversion panel 13.

This incident transmitted image is the radiation l1Iil image conversion panel/3
is absorbed into the stimulable phosphor layer by ZL, and a number of electrons or holes proportional to the radiation dose are generated in the phosphor layer, which increases the trap level of the stimulable phosphor. is accumulated in Ie radiation #! An accumulated image (-m image of food) of the transmission image is formed. Next, this A1 area is the former A. Luguite W.
J rise and manifest. That is, the excitation light emitted from the light source /l emits the stimulable phosphor I-
was scanned to drive out the electrons or holes accumulated at the trap level, and the accumulated image was emitted as fluorescent light. As mentioned above, the excitable wavelength range of the monovalent europium-activated composite halide phosphor used in the stimulable phosphor layer of the radiation fusion conversion panel 3 is 4Ajo to oonm, Since the optimum excitation wavelength range is pro to 7j Onm, electromagnetic waves having a wavelength of pro to oonm, preferably ≠IO to 7j Onm, are used as the excitation light. In this range (4410 to 7 jOnm), the stimulable phosphor layer can be excited without substantially increasing its temperature, so that deterioration of the phosphor and the phosphor layer due to temperature changes can be prevented.

The intensity of the fluorescent light emitted from the phosphor layer due to excitation by the excitation light depends on the number of accumulated electrons or holes, that is, the intensity of the radiation-energy absorbed by the phosphor layer of the radiation-image conversion panel 13. This original signal is converted into an electrical signal using a photoelectric conversion device, such as a photomultiplier tube.
The image reproduction device 16 reproduces the image as an image, and the m-image display device 1lt17 displays this m-image.

The radiation-image converting panel used in the radiation-temperature distribution method of the present invention is a phosphor material containing a europium-activated composite halide phosphor having a valence of 6 cλ dispersed in a suitable binder. have If the phosphor layer is self-supporting, the stimulable phosphor layer itself can serve as a radiation image conversion panel, but generally the phosphor layer is provided on a suitable skinned body.
A radiation 111gl conversion panel is constructed. Furthermore, usually, a straining membrane is provided on one side of the phosphor layer (on the side opposite to the side on which the support is provided) for physically or chemically deepening the phosphor layer. Further, a lower molding layer may be provided between the phosphor layer and the support in order to bring the phosphor layer and the support into closer contact with each other. Incidentally, a radial-like image conversion panel having a structure similar to the one shown above can be obtained from a radial-like image conversion panel as disclosed in Japanese Patent Application Laid-open No. 1/63J00.
(If the phosphor layer is not colored, it is preferably colored so that the degree of dusk gradually increases from the excitation light incident side to the opposite side.)

In addition to the cerium-activated trivalent metal oxyhalide phosphor of the present invention, the phosphor layer of the radiation image storage panel may optionally contain one of the known stimulable phosphors.
A photostimulable phosphor that emits light by stimulation with electromagnetic waves in the wavelength range may be used in combination.

Preferred known #1 exhaustible fluorophores to be used in combination are 4
1iPiII! Rare earth-activated lanthanum quinhalide phosphor listed in No. 11-/Col No. 3, U.S. Tokuken #I
No. 44,234,071, Japanese Unexamined Patent Publication No. 11/1973/λllJ,
Same jz-isi≠! No. 1l-141JIf No. 4j
4-23ts issue, j4-2314 issue, j4-7≠/
Examples include rare earth-activated alkaline earth metal fluorohalide phosphors described in No. 71 and the like.

In addition, white powder may be dispersed in the phosphor layer of the radiant l/M111 reversible panel as shown in Japanese Patent Application Laid-Open No. 11-1989/$44'-7. In addition, the Radiation 1Iil image conversion panel is available from Tokukai Seita-//Juri No. 3 or Toku-Sho! A metal reflective layer or a white powder reflective layer may be provided on the opposite side of the phosphor layer from the excitation nine-incidence bar as disclosed in No. 1atoo. By using colorants or white powders, the light reflection l
By providing K, it is possible to obtain a radiation-to-self conversion panel that provides images with high sharpness.

In the radiation f*f Chinese method of the present invention, the source energy light source that excites the phosphor layer of the prodigal image conversion panel emits light with a band spectrum distribution in the wavelength range from ≠jO to oonm. In addition to light sources with a single wavelength, such as He"-Ne laser light (AjJnm), YAG laser light (10A hronm), ruby L/- laser light (62 nm), and argon laser (see lfI'mm), A light source that emits light is used. In particular, when a laser beam is used, a high excitation energy can be obtained. It is more preferable to use le-Ne laser beam (among other laser beams).

Next, the present invention will be explained by examples.

Example Nd, 0,141.2171 (0,r mol), NHBY
/4At, Rif (/, 1 mol) and CeO□0. /7
Co., Ltd. (10-" mol) was weighed out and thoroughly mixed using a ball mill. The resulting mixture was filled with a quartz board and placed in an electric furnace for firing. This firing was performed by first having a volume of 1-
The firing was carried out in a nitrogen gas atmosphere containing hydrogen gas at a temperature of zoo0c for 2 hours, and then the temperature was raised to /100"c and the firing was carried out in the same atmosphere for 2 hours. After firing, the obtained fired product was loosened and passed through a sieve. .In this way, the Nd0 of the present invention
A Br, to Ce phosphor was obtained.

This phosphor exhibited instantaneous blue light emission whose emission spectrum is shown in FIG. 1 under excitation with Xd, electron beams, ultraviolet rays, etc. Furthermore, this phosphor exhibited blue stimulated luminescence when excited with He--Ne laser light (jJJnm) after irradiation with X-rays.

Nd2O,0,! Pr2O3, Pm20 instead of mole O
．． ．． 8m20a, Eu2O,, Tb40. , DYUHO
20,, Er20. ,T111sOn,! 3\ Yb2O3 and Bi2O3 are 0 for Tb4O7
．． 2! PrOBr:
10"Ce'i!' light body, Pm0Br:10"Ced nine bodies, Smυf3r:10"Ce fluorescent body, Eu0Br:1
0”Cue phosphor, Tb0Br:1O-3Ce phosphor,
D”jOBr:10-30:e fluorophore, Ho0BrH1
0-3Ce, l photon, Er0Br:1O-3ce phosphor, TmUHr:1O-3ce phosphor, Yb0Br:1O
-3Ce phosphor Jr! and BjOBr: 1o-3Ce fluoride body was left behind. All of these phosphors showed instantaneous light emission of W color, whose emission spectrum was almost the same as that shown in the figure 4, under excitation F with Xd, electron beams, ultraviolet rays, etc. dkHe-rQev-f' also irradiated with Xd
-ft, TeIfdJi&T and blue j1 emission gold was shown.

[Brief explanation of the drawing]

Figure 1 illustrates the original spectrum of the cerium-added trivalent metal oxy7 halide phosphor of the present invention. FIG. 4 illustrates the stimulated excitation spectrum of the cerium-added trivalent metal oxide/halide phosphor of the present invention. FIG. 3 is a schematic diagram of a radiation m-image conversion method using stimulated luminescence of a phosphor according to the present invention. /l... Radiation edge generator, lλ... Subject, 13.
... Radiation m-image conversion panel, /4... Light source, /j...
Photoelectric conversion device, /4... Image reproduction device, 17...1
Monk display device, /I...filter.

Claims (1)

[Scope of Claims] At least one OJ-valent metal selected from the group consisting of the composition formula Bt, X is either one or both of α and Br, and X satisfies 0<X<0. A cerium-activated trivalent metal oxyhalide phosphor represented by a number satisfying the following condition: