Source: http://www.google.com/patents/US4645721?dq=6016038
Timestamp: 2018-01-18 13:02:48
Document Index: 700309359

Matched Legal Cases: ['application No. 497', 'application No. 520', 'application No. 502', 'application No. 535', 'application No. 543', 'application No. 660', 'application No. 668', 'Application No. 60', 'application No. 660', 'application No. 723', 'application No. 727', 'application No. 727', 'Application No. 59', 'Application No. 59', 'Application No. 60', 'Application No. 60']

Patent US4645721 - Radiation image storage panel - Google Patents
A radiation image storage panel comprising a support, a phosphor layer which comprises a binder and a stimulable phosphor dispersed therein and a protective film, superposed in this order, characterized in that a thin film comprising an inorganic material is provided on a surface of the panel....http://www.google.com/patents/US4645721?utm_source=gb-gplus-sharePatent US4645721 - Radiation image storage panel
Publication number US4645721 A
Application number US 06/818,239
Also published as EP0188274A2, EP0188274A3
Publication number 06818239, 818239, US 4645721 A, US 4645721A, US-A-4645721, US4645721 A, US4645721A
Inventors Satoshi Arakawa, Terumi Matsuda
US 4645721 A
A radiation image storage panel comprising a support, a phosphor layer which comprises a binder and a stimulable phosphor dispersed therein and a protective film, superposed in this order, characterized in that a thin film comprising an inorganic material is provided on a surface of the panel.
1. A radiation image storage panel comprising a support, a phosphor layer which comprises a binder and a stimulable phosphor dispersed therein and a protective film, superposed in this order, characterized in that a thin film comprising an inorganic compound selected from the group consisting of inorganic nitrides, inorganic carbides, inorganic oxides, and inorganic fluorides, all having a property of being resistant to damage is provided on a surface of the panel.
6. The radiation image storage panel as claimed in claim 5, in which said thin film having the anti-reflecting property comprises MgF2.
9. The radiation image storage panel as claimed in claim 8, in which said thin film having the antistatic property comprises at least one inorganic compound selected from the group consisting of In2 O3, SnO2 and ZnO.
It is an object of the present invention to provide a radiation image storage panel having a high hardness on the panel surface.
ZnS:Cu,Pb, BaO.xAl2 O3 :Eu, in which x is a number satisfying the condition of 0.8≦x≦10, and MII O.xSiO2 :A, in which MII is at least one divalent metal selected from the group consisting of Mg, Ca, Sr, Zn, Cd and Ba, A is at least one element selected from the group consisting of Ce, Tb, Eu, Tm, Pb, Tl, Bi and Mn, and x is a number satisfying the condition of 0.5≦x≦2.5, as described in U.S. Pat. No. 4,236,078;
(Ba1-x,M2+ x)FX:yA, in which M2+ is at least one divalent metal selected from the group consisting of Mg, Ca, Sr, Zn and Cd, X is at least one element selected from the group consisting of Cl, Br and I, A is at least one element selected from the group consisting of Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb and Er, and x and y are numbers satisfying the conditions of 0≦x≦0.6 and 0≦y≦0.2, respectively, as described in U.S. Pat. No. 4,239,968;
(Ba1-x, MII x)F2.aBaX2 :yEu,zA, in which MII is at least one element selected from the group consisting of Be, Mg, Ca, Sr, Zn and Cd; X is at least one element selected from the group consisting of Cl, Br and I; A is at least one element selected from the group consisting of Zr and Sc; and a, x, y and z are numbers satisfying the conditions of 0.5≦a≦1.25, 0≦x≦1, 10-6 ≦y≦2×10-1, and 0<z≦10-2, respectively, as described in Japanese Patent Provisional Publication No. 56(1981)-116777;
(Ba1-x,MII x)F2.aBaX2 :yEu,zB, in which MII is at least one element selected from the group consisting of Be, Mg, Ca, Sr, Zn and Cd; X is at least one element selected from the group consisting of Cl, Br and I; and a, x, y and z are numbers satisfying the conditions of 0.5≦a≦1.25, 0≦x≦1, 10-6 ≦y≦2×10-1, and 0<x≦2×10-1, respectively, as described in Japanese Patent Provisional Publication No. 57(1982)-23673;
(Ba1-x, MII x)F2.aBaX2 :yEu,zA, in which MII is at least one element selected from the group consisting of Be, Mg, Ca, Sr, Zn and Cd; X is at least one element selected from the group consisting of Cl, Br and I; A is at least one element selected from the group consisting of As and Si; and a, x, y and z are numbers satisfying the conditions of 0.5≦a≦1.25, 0≦x≦1, 10-6 ≦y≦2×10-1, and 0<z≦5×10-1, respectively, as described in Japanese Provisional Publication No. 57(1982)-23675;
Ba1-x Mx/2 Lx/2 FX:yEu2+, in which M is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; L is at least one trivalent metal selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, In and Tl; X is at least one halogen selected from the group consisting of Cl, Br and I; and x and y are numbers satisfying the conditions of 10-2 ≦x≦0.5 and 0<y≦0.1, respectively, as described in U.S. patent application No. 497,805, now abandoned;
BaFX.xA:yEu2+, in which X is at least one halogen selected from the group consisting of Cl, Br and I; A is at least one fired product of a tetrafluoroboric acid compound; and x and y are numbers satisfying the conditions of 10-6 --x≦0.1 and 0<y≦0.1, respectively, as described in U.S. patent application No. 520,215, now abandoned;
BaFx:xA:yEu2+, in which X is at least one halogen selected from the group consisting of Cl, Br and I; A is at least one fired product of a hexafluoro compound selected from the group consisting of monovalent and divalent metal salts of hexafluoro silicic acid, hexafluoro titanic acid and hexafluoro zirconic acid; and x and y are numbers satisfying the conditions of 10-6 ≦x≦0.1 and 0<y<0.1, respectively, as described in U.S. patent application No. 502,648, now abandoned;
MII FX.xNaX':yEu2+ :zA, in which MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; each of X and X' is at least one halogen selected from the group consisting of Cl, Br and I; A is at least one transition metal selected from the group consisting of V, Cr, Mn, Fe, Co and Ni; and x, y and z are numbers satisfying the conditions of 0<x≦2, 0<y≦0.2 and 0<z≦10-2, respectively, as described in U.S. patent application No. 535,928, now U.S. Pat. No. 4,505,989;
MII FX.aMI X'.bM'II X"2.cMIII X"'3.xA:yEu2+, in which MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; MI is at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; M'II is at least one divalent metal selected from the group consisting of Be and Mg; MIII is at least one trivalent metal selected from the group consisting of Al, Ga, In and Tl; A is metal oxide; X is at least one halogen selected from the group consisting of Cl, Br and I; each of X', X" and X"' is at least one halogen selected from the group consisting of F, Cl, Br and I; a, b and c are numbers satisfying the conditions of 0≦a≦2, 0≦b≦10-2, 0≦c≦10-2 and a+b+c≦10-6 ; and x and y are numbers satisfying the conditions of 0<x≦0.5 and 0<y≦0.2, respectively, as described in U.S. patent application No. 543,326, now abandoned;
MII X2.aMII X'2 :xEu2+, in which MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; each of X and X' is at least one halogen selected from the group consisting of Cl, Br and I, and X≠X'; and a and x are numbers satisfying the conditions of 0.1≦a≦10.0 and 0<x≦0.2, respectively, as described in U.S. patent application No. 660,987, now abandoned;
MII FX.aMI X':xEu2+, in which MII is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; MI is at least one alkali metal selected from the group consisting of Rb and Cs; X is at least one halogen selected from the group consisting of Cl, Br and I; X' is at least one halogen selected from the group consisting of F, Cl, Br and I; and a and x are numbers satisfying the conditions of 0≦a≦4.0 and 0<x≦0.2, respectively, as described in U.S. patent application No. 668,464, now abandoned; and
MI X:xBi, in which MI is at least one alakli metal selected from the group consisting of Rb and Cs; X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a number satisfying the condition of 0<x≦0.2, as described in Japanese Patent Application No. 60(1985)-70484.
The MII X2.aMII X'2 :xEu2+ phosphor described in the above-mentioned U.S. patent application No. 660,987, now abandoned, may contain the following additives in the following amount per 1 mol of MII X2.aMII X'2 :
bKX".cMgX"'2.dMIII LLX""3, in which MIII is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu; each of X", X"' and X"" is at least one halogen selected from the group consisting of F, Cl, Br and I; and b, c and d are numbers satisfying the conditions of 0≦b≦2.0, 0≦c≦2.0, 0≦d≦2.0 and 2×10-5 ≦b+c+d, as described in U.S. patent application No. 723,819, now abandoned;
yB, in which y is a number satisfying the condition of 2×10-4 ≦y≦2×10-1, as described in U.S. patent application No. 727,974;
bA, in which S is at least one oxide selected from the group consisting of SiO2 and P2 O5 ; and b is a number satisfying the condition of 10-4 ≦b≦2×10-1, as described in U.S. patent application No. 727,972;
bSiO, in which b is a number satisfying the condition of 0<b≦3×10-2, as described in Japanese Patent Application No. 59(1984)-240452;
bSnX"2, in which X" is at least one halogen selected from the group consisting of F, Cl, Br and I; and b is a number satisfying the condition of 0<g≦10-3, as described in Japanese Patent Application No. 59(1984)-240454;
bCsX".cSnX"'2, in which each of X" and X"' is at least one halogen selected from the group consisting of F, Cl, Br and I; and b and c are numbers satisfying the conditions of 0<b≦10.0 and 10-6 ≦c≦2×10-2, respectively, as described in Japanese Patent Application No. 60(1985)-78033; and
bCsX".yLn3+, in which X" is at least one halogen selected from the group consisting of F, Cl, Br and I; Ln is at least one rare earth selected from the group consisting of Sc, Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; and b and y are numbers satisfying the conditions of 0<b≦10.0 and 10-6 ≦y≦1.8×10-1, respectively, as described in Japanese Patent Application No. 60(1985)-78035.
In the radiation image storage panel of the invention, the thin film comprises at least one inorganic compound such as an inorganic fluoride, an inorganic oxide, an inorganic nitride or an inorganic carbide, Examples of the inorganic compound employable in the invention includes fluorides such as MgF2, CaF2, BaF2 and cryolite; oxides such as MgO, CaO, B2 O3, Al2 O3, ZrO2, TiO2, SiO, SiO2, ZnO, In2 O3, SnO2 and ITO (mixed crystal of In2 O3 and SnO2); nitrides such as BN and Si3 N4 ; and carbides such as SiC, TiC and WC. When a thin film is formed on the protective film by using any of these compounds, hardness of the panel surface can be enhanced.
From the viewpoint of the improvement in the resistance to damage, the inorganic compound is preferably MgF2, CaF2, BaF2, cryolite, MgO, CaO, B2 O3, ZnO, In2 O3, SnO2, ITO, BN, Si3 N4, SiC, TiC or WC. Among these compounds, the nitrides and carbides are particularly preferred. The thin film comprising the above-mentioned compound (which may be called a "damage-resistant film") preferably has a thickness within the range of 500 to 20,000 angstrom.
Further, from the viewpoint of the improvement in the anti-reflection, the inorganic compound is preferably a fluoride such as MgF2, CaF2 or cryolite; or an oxide such as Al2 O3, ZrO2, TiO2, SiO or SiO2. Any of these compounds has a low reflectance for stimulating rays to excite the stimulable phosphor in the panel, that is, the compound has a low reflectance for the electromagnetic wave in the wavelength region of the excitation thereof. Further, the compound has a low absorption coefficient for the stimulating rays, namely has a high transmittance therefor. The thin film comprising said compound (which may be called an "anti-reflecting film") preferably has a thickness in such an order as the wavelength of the stimulating rays. Particularly preferable is an optical thickness of odd times 1/4 of the wavelength of the stimulating rays (thickness being equal to n λ/4 wherein n=1, 3, 5, . . . , when λ represents the wavelength), which provides a noticeably low reflectance to the thin film. The anti-reflecting film may comprises multiple layers, whereby a reflectance thereof is more decreased. Each layer of the multiple film basically has a thickness of the odd times 1/4 of the wavelength, but the anti-reflecting film may be a transmissive multiple film in which each layer has a thickness deviated from the odd times 1/4 of the wavelength. The thickness of the anti-reflecting film is generally within the range of 10 to 1,000 angstrom.
Otherwise, from the viewpoint of the improvement in the antistatic property, the inorganic compound is preferably a conductive oxide such as ZnO, In2 O3, SnO2 or ITO(mixed crystal of In2 O3 and SnO2). Any of these compounds has a high conductivity and a thin film thereof provides the antistatic effect to the panel. The thin film comprising the above-mentioned compound (which may be called an "antistatic film") preferably has a thickness within the range of 100 to 5,000 angstrom.
To a mixture of a particulate divalent europium activated barium fluorobromide (BaFBr:0.001Eu2+) phosphor and a linear polyester resin were added successively methyl ethyl ketone and nitrocellulose (nitration degree: 11.5%), to prepare a dispersion containing the phosphor particles. Subsequently, tricresyl phosphate, n-butanol and methyl ethyl ketone were added to the dispersion. The mixture was sufficiently stirred by means of a propeller agitator to obtain a homogeneous coating dispersion having a mixing ratio of 1:10 (binder:phosphor, by weight) and a viscosity of 25-35 PS (at 25° C.).
The coating dispersion was applied evenly onto a polyethylene terephthalate sheet (support, thickness: 250 μm) placed horizontally on a glass plate. The application of the coating dispersion was carried out using a doctor blade. After the coating was complete, the support having a layer of the coating dispersion was placed in an oven and heated at a temperature gradually rising from 25° to 100° C. Thus, a phosphor layer having a thickness of approx. 250 μm was formed on the support.
The procedure of Example 1 was repeated except for not forming a thin film of TiC on the protective film, to prepare a radiation image storage panel consisting essentially of a support, a phosphor layer and a transparent protective film.
The radiation image storage panels prepared in Example 1 and Comparison Example 1 were evaluated on the occurrence of scratches according to the following test.
A phosphor layer and a transparent protective film were provided on a support in the same manner as described in Example 1.
Subsequently, magnesium fluoride (MgF2) was deposited on the transparent protective film in a thickness of approx. 1,580 angstrom [1/4 of the wavelength (632.8 nm) of a He-Ne laser] by vaccum deposition, to form a thin film comprising MgF2 (anti-reflecting film) on the protective film.
Thus, a radiation image storage panel consisting essentially of a support, a phosphor layer, a transparent protective film and a thin film of MgF2 was prepared.
The radiation image storage panels prepared in Example 2 and Comparison Example 1 were evaluated on the surface reflectance. The reflectance of the protective film-side surface of the panel is measured using a He-Ne laser (632.8 nm).
The radiation image storage panels prepared in Examples 3-6 and Comparison Example 1 were evaluated on electrical resistance of the panel surface according to the following test.
The radiation image storage panel was cut to give a test strip having a size of 110 mm×110 mm. The test strip was placed on a circular electrode (P-601 type, manufactured by Kawaguchi Electric Co., Ltd.) provided with an insulation resistance tester (EV-40 type super-insulation resistance tester, manufactured by the same) and then the voltage was set to measure the electric resistance of the surface (SR) of the test strip at a temperature of 23° C. and at a humidity of 50% RH. The obtained surface resistance is represented by logarithmic value (log SR).
TABLE 1______________________________________                 Surface Resistance    Inorganic Compound                 (ohm)______________________________________Example3          In.sub.2 O.sub.3                     74          SnO.sub.2      45          ITO            46          ZnO            8Com. Example1          --             >15______________________________________
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U.S. Classification 428/690, 250/484.4, 976/DIG.439, 250/581, 250/483.1
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:ARAKAWA, SATOSHI;MATSUDA, TERUMI;REEL/FRAME:004516/0929
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ARAKAWA, SATOSHI;MATSUDA, TERUMI;REEL/FRAME:004516/0929