JP2005187817A - Method for preparing storage phosphor from precursor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preparing a CsX:Eu stimulable phosphor and a screen or a panel provided with the phosphor as powder phosphor or vapor deposited needle-shaped phosphor suitable for use in an image forming method for recording and reproducing images of an object made by high energy radiation. <P>SOLUTION: The CsX:Eu stimulable phosphor is essentially free from oxygen in its crystal structure, and wherein X represents a halide selected from the group consisting of Br, Cl and combinations thereof. The method comprises the steps of mixing CsX with a compound or combinations of precursor compounds having as a composition Cs<SB>x</SB>Eu<SB>y</SB>X'<SB>x+αy</SB>, heating the mixture at a temperature ≥450°C, cooling the mixture, and optionally annealing and recovering the CsX:Eu stimulable phosphor, wherein the ratio of x/y exceeds a value of 0.25, wherein α≥2 and X' is a halide selected from the group consisting of Cl, Br and I and combinations thereof. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a solution for the synthesis or production of impurities-free, in particular oxygen-free, CsBr: Eu phosphors, a method for producing a screen or panel using said phosphor, and an image using said screen or panel It relates to the forming method.

  A well-known use of storage phosphors is the generation of X-ray images. US-A 3859527 discloses a method for generating an X-ray image with a photostimulable phosphor contained in a phosphor panel. The panel is exposed to an X-ray beam modulated according to the incident pattern, so that the phosphor temporarily stores the energy contained in the X-ray radiation pattern. At some interval after exposure, a beam of visible or infrared light scans the panel and stimulates the emission of stored energy as light. The light is detected and sequentially converted into an electrical signal that is processed to produce a visible image. For this purpose, the phosphor should store as much of the incident X-ray energy as possible and emit as little of the stored energy until stimulated by the scanning beam. This is referred to as “digital radiography” or “computer radiography”.

  The image quality produced by any radiographic system that uses a phosphor screen, and therefore by a digital radiographic system, is highly dependent on the configuration of the phosphor screen. In general, the thinner the phosphor screen at a given amount of x-ray absorption, the better the image quality.

  This means that the lower the binder to phosphor ratio of the phosphor screen, the better the image quality that can be achieved with that screen. Thus, optimum sharpness can be obtained when a screen without any binder is used. Such a screen can be produced, for example, by physical vapor deposition of a phosphor material on a support, which may be thermal vapor deposition, sputtering, electron beam vapor deposition, and the like. However, this production method cannot be used to produce high quality screens with all available phosphors. The manufacturing method described above leads to the best results when a phosphor is used in which the crystals are co-melted.

  The use of alkali metal halide phosphors in storage screens or panels is well known in the field of storage phosphor radiation, and the high coincidence melt of these phosphors produces structured and binderless screens. Make it possible to do.

  It is disclosed that when binderless screens with alkali halide phosphors are produced, it is beneficial to deposit phosphor crystals in several types, such as piles, needles, tiles, etc. ing. US-A 4,769,549 discloses that the image quality of a binderless phosphor screen can be improved when the phosphor layer has a block structure formed of thin pillars.

  US-A 5,055,681 discloses a storage phosphor screen with a pile-like structure and containing an alkali halide phosphor. The image quality of such a screen still needs to be improved, and JP-A 06/230198 discloses that the surface of the screen with columnar phosphors is rough and the height of the surface can improve its sharpness. . In U.S. Pat. No. 5,874,744, attention is paid to the reflectivity of the phosphors used to produce storage phosphor screens with needle-like or columnar phosphors.

EP-A 111 13 458 discloses a binderless storage phosphor screen comprising an alkali metal storage phosphor, wherein the screen has an intensity I ₁₀₀ such that I ₁₀₀ / I ₁₁₀ ≧ 1 (100) diffraction. It has a linear and intensity _{I 110} (110), characterized in that an XRD spectrum having diffraction lines. Such phosphor screens show a better compromise between speed and sharpness.

  When excited with high energy radiation, excitons or electron / hole pairs are created in prompt phosphors and scintillators. The subsequent recombination of electrons and holes releases the energy used for the creation of luminescent photons, ie for the luminescence process. The presence of defects in the phosphor material creates an additional energy level in the band gap. As a result, electrons can be deexcited in many small steps. The resulting energy packet is too small to cause photon emission. Instead, the energy is converted into so-called photons or lattice vibrations. That is, the excitation energy is lost in the form of heat.

  Similar to prompt phosphors, high energy radiation creates electron-hole pairs in the storage phosphor. In these materials, many electron-hole pairs do not recombine directly. Instead, electrons are trapped in the electron trap and holes are trapped in the hole trap. Subsequent stimulation of the storage phosphor with a long wavelength range of light, such as red light, allows the captured electrons to absorb photons. The photons provide enough energy to escape from the trap. Such escape is followed by recombination with holes and stimulated luminescence.

  Traps in storage phosphors are often inherent lattice defects. For example, in alkaline earth halides and alkaline halide storage phosphors, electrons are trapped in halide vacancies, which are thus converted to F centers. If the storage phosphor crystal lattice is contaminated with extraneous elements, additional defects are created. These defects adversely affect luminescence as in prompt phosphors. Furthermore, these defects can compete with inherent lattice defects as electron trapping centers. The additional defects are generally too unstable to be useful for long-term energy storage or too stable so that no electrons are released upon stimulation.

  Therefore, it is most important to avoid contamination with foreign elements in the prompt phosphor and also in the storage phosphor.

  In addition, the high moisture content of the raw material mixture may cause trouble as a source fluctuation, which may later cause unacceptable inhomogeneities in the screen when assessing quality.

  Many contaminations can be avoided by using very pure materials in the phosphor synthesis process. Other contamination is more difficult to prevent.

  Alkali halides and alkaline earth halide phosphors are often mixed with oxides. The source of this contaminating element can often be water absorbed on the surface of slightly hygroscopic salt particles, in particular on the surface of Eu compound derivatives. In the synthesis of CsBr: Eu storage phosphors by prior art methods, dopant materials are often recognized as a source of oxygen incorporation.

In EP-A 1276117, the synthesis of CsBr: Eu starting from CsBr and a europium compound selected from the group consisting of Eu (II) halide, Eu (III) halide and Eu oxyhalide is Eu ₂ O as dopant material. Is described as an improvement over the use of ₃ . It is clear that the use of the dopant compounds described above reduces the amount of oxygen in the reaction mixture.

However, the use of europium halide EuX _n (2 ≦ n ≦ 3) or europium oxyhalide (EuOX) may be accompanied by oxygen contamination. It is clear that some oxide contamination occurs when EuOX (X represents a halide) is used. When EuOX decomposes at temperatures above 700 ° C. (which represents a temperature at least 100 ° C. above the melting temperature of CsBr: Eu), the evaporation process lacks a “single phase” process from its initial stage, and the starting material It is clear that when everything is mixed into only one crucible, phase separation occurs and further causes instabilities in the deposition process. This phenomenon is even more so when shaking occurs during the evaporation process and inhomogeneous deposition on the phosphor support. After strict separation of the raw material in several (at least two) crucibles, two crucibles or boats for the production of the phosphor in such a way that the resulting phosphor particles meet the stoichiometric conditions The solution can be sought by evaporating the raw material or precursor from However, such a solution requires a strict geometric arrangement in the deposition chamber, which can impose process reproducibility because the evaporation of Cs and Eu compounds takes place after melting at different temperatures.

Furthermore, even if EuX _n (2 ≦ n ≦ 3) is used, which at first glance has no “structural” presence of oxygen, oxygen contamination will occur unless very strict precautions are taken.

EuX _n (2 ≦ n ≦ 3) compounds are known to be extremely hygroscopic. For example, EuBr ₃ is EuBr _3. It is only commercially available as 6-9H ₂ O, with an indefinite number of water molecules bound as “crystal water”. When this material is heated, hydrolysis occurs and EuOBr is formed.

In order to avoid hydrolysis, dehydration must be completed. This is because the presence of one molecule of water per molecule of EuBr ₃ is sufficient for complete conversion to EuOBr and HBr. Similar problems exist with other europium halides.

Hydrolysis and subsequent conversion to europium oxyhalide can be avoided if the europium halide is heated to temperatures below 200 ° C. under reduced pressure for extended periods of time. However, because of the significant amount, this process can take days or even be impossible to complete.

  However, the resulting dehydrated europium halide will absorb water as soon as it is exposed to the ambient atmosphere. This means that mixing with the CsBr matrix material must be done in a room or glove box with a conditioned and completely dry atmosphere. Also, take precautions to avoid water absorption during the transfer of materials to a reaction environment, such as a furnace to make CsBr: Eu powder or a vapor deposition chamber to make a CsBr: Eu phosphor layer by vapor deposition. Should.

Alternatively, the water-containing raw material mixture consisting of CsBr and dehydrated _{EuX n (2 ≦ n ≦ 3} ) is CsBr: CsBr by the furnace or deposition for making Eu powder: the reaction environment, such as the deposition chamber to make Eu layer Can be dried.

Thus, in the application US-A1-2003 / 0104121, the corresponding EP-A-1217633 and the PCT application WO-A-0103156, a CsX: Eu phosphor screen is produced, which can be used as a starting raw material to give a europium dopant or activator, for example EuBr. _The manufacturing process includes mixing 10 ⁻³ mol% to 5 mol% of a europium compound such as ³ with CsX and subsequently depositing the mixture on a support to form a binder-free phosphor screen.

  However, drying the raw material mixture in the furnace is extremely time consuming and even impossible because the water must diffuse through the thick powder layer. Even for the limited thickness of the powder layer, the drying process may require several days, which makes the phosphor synthesis process extremely time consuming and insufficient.

  When the raw material mixture is dried in a vacuum chamber where vapor deposition is to take place, a large amount of water vapor will be released. This will prevent decompression and cause corrosion. Water is immediately absorbed at the vacuum chamber walls and removal of the absorbed water will again be very time consuming.

  In order to provide a method for melting and solidifying a high-purity europium halide particularly useful as a raw material for vapor deposition, JP-A 2003-201119 describes a method for melting europium halide and a method for manufacturing a solidified body. Europium halide is melted by heating and then cooled in the presence of a halogen source, such as ammonium halide, or such halogen, preferably in an atmosphere of dry air. However, corrosion of surrounding materials can occur in the presence of such compounds. Furthermore, it takes a very long time to carry out the drying treatment at a temperature up to 400 ° C. under reduced pressure during a heating time of 1 to 10 hours.

  In addition to the problems associated with hygroscopicity and corrosion, many uncertain oxides can be present in different ratios, so the purity of the starting material is given very vaguely and even different uncertain “phase” crucibles. An unstable vapor flow or non-uniform deposition can occur because the presence in can cause squirting or shaking while vaporizing the starting material.

  The object of the present invention is therefore to provide a method, in particular a synthesis method, for producing CsBr: Eu as a deposited CsBr: Eu phosphor or as a powder phosphor in a layer, said CsBr: Eu phosphor Has excellent reproducible quality.

  In particular, it is an object of the present invention to provide an effective method for producing CsBr: Eu phosphors in powder form or needle-shaped layer form, wherein the phosphor is present in a small amount as a contaminant in the phosphor crystal lattice. Not included.

The “effective method” “requires no special precautions to avoid water being absorbed by the starting material mixture” and “requires a time-consuming drying step during phosphor synthesis. should be understood as "not to, in which in the temperature range between the melting point of the component having a melting point and crucible of eutectic composition of CsBr and EuBr _n is heated, the vapor phase is held more constant Can.

The above objective is to obtain the general formula Cs _x Eu _y X ′ _{x + αy} (where X ′ is a halide selected from the group of Cl, Br and I, α ≧ 2, and x / y is a value of 0.25. Is used as a dopant material in the synthesis of CsBr: Eu.

  Specific features for preferred embodiments of the invention are set out in the dependent claims.

  Further advantages and embodiments of the present invention will become apparent from the following description.

Less-Common Materials, Vol. 127 (1987), p. As described in the 155-160 periodicals, the “drying route” followed by treatment with ammonium bromide followed by “ammonium bromide route for dehydrating rare earth bromides” in the first step Eu ₂ O ₃ "Gives europium bromide complex salts (NH ₄ ) ₂ EuBr ₅ and (NH ₄ ) ₃ EuBr ₆ where EuOBr is formed in a competitive reaction. As an alternative, in a wet manufacturing process, a mixture of NH ₄ Br and Eu ₂ O ₃ is heated in concentrated HBr. Hydrated EuBr ₃ . Although 6 aq may be used, an excess of NH ₄ Br is required to avoid hydrolysis and formation of EuOBr.

(NH ₄ ) ₂ EuBr ₅ and (NH ₄ ) ₃ EuBr ₆ should be stored in a dry state to avoid hydrolysis or hydrate formation, which may lead to oxybromide contamination during the decomposition of tribromide. Lead. However, decomposition of these ternary complex salts under reduced pressure at temperatures ranging from 350 to 400 ° C. leads to the desired binary EuBr ₃ in the final decomposition step.

In another method, EuBr ₂ is made starting from Eu ₂ O ₃ as a starting material, dissolved in dilute HBr and evaporated after the addition of NH ₄ Br, where EuBr ₃ is Mh. Chem. , Bd97, p. Separate into EuBr ₂ and Br ₂ as described in 863-865.

More useful information on the phase equilibrium, evaporation behavior and thermodynamic properties of europium tribromide can be found in Chem. Thermodynamics, Vol. 5 (1973), p. 283-290, where there is a reversible equilibrium between tetragonal Eu dibromide, orthorhombic dark rust tea Eu tribromide, and bromine where Eu tribromide to Eu dibromide. It has been clearly shown that the disproportionation process to bromide and bromine is very temperature dependent. And the disproportionation process starts at a temperature of 200 ° C. and the equilibrium between the more hygroscopic Eu tribromide and the less hygroscopic Eu bromide is achieved after further calcination when the reaction is clearly endothermic. It has been shown that it is only done. As a result, the condensed phase with altered composition is measured up to the EuBr _2.2 composition.

In US-A 2003/00424429, it is preferred that the europium compound used in tablet form by compression is first treated by the trivalent europium reduction method, then isolated and degassed before compression. In addition to CsBr as the main component (amount of at least 90 mol%), the tablets contain the europium compound in an amount of up to 10%. Before starting the compression, it is required to heat the powder mixture in a nitrogen atmosphere and to burn it at 525 ° C. for 2 hours, where the burned powder is evacuated to remove as much moisture as possible. At 200 ° C. and degassed. After compressing the powder into tablets (requiring a high force of 800 kg / cm ² ), the tablet evaporation process is carried out by application of an electron beam.

In the present invention, a more convenient and less moisture sensitive method is found, where CsBr and Cs _x Eu _y X ′ _{x + αy} (where x / y> 0.25, α ≧ 2) as the main components, An evaporation process has been developed starting from X 'is a halide selected from the group consisting of Cl, Br and I and combinations thereof. Rare Metals, Vol. 21 (1), March 2002, p. As described in 36-42, molten salt phase diagram evaluation by pattern recognition can be performed without experimental evidence such as CsEu ₃ Br ₇ (CsBr is present in an amount less than 50%), perovskite-like CsEuBr ₃ (CsBr is EuBr present in an amount equilibrium as _2), and _Cs 3 EuBr ₅ (CsBr leads to the prediction of the existence of intermediate compounds, such as present in an amount greater than 50%), in all of the intermediate compounds, the divalent europium Present as an activator element or dopant.
These experimental evidence of the presence of the intermediate can be derived from XRD analysis of the obtained salt, XRD signals _{CsBr, EuOBr, EuBr 3, EuBr} 2, Eu 3 as _O 4 Br and _Eu 2 _{O 3} It appears different from any well-known signal.

According to the method of the present invention, the production of CsX: Eu stimulated phosphor (where X represents a halide selected from the group consisting of Br, Cl and combinations thereof) is performed by the following steps:
Cs _x Eu _y X ′ _{x + αy} as composition (where x / y> 0.25, α ≧ 2, X ′ is a halide selected from the group consisting of Cl, Br and I and combinations thereof) A precursor compound or a combination of precursor compounds having CsX with
-Heating the mixture at a temperature of 450 ° C or higher;
-Cooling said mixture;
-Recovering the CsX: Eu phosphor if desired.

  In a preferred example according to the method of the invention, the ratio x / y = 1, more preferably x / y> 1, even more preferably x / y = 3, most preferably x / y> 3.

  Further, the method of the present invention includes the step of annealing at a temperature T in the range of 25 ° C. to 400 ° C. in an inert atmosphere, air or oxygen atmosphere.

In a raw material mixture ("raw material mixture" is to be understood as a mixture of salts containing Eu precursor and CsBr salt, said CsBr salt is added to obtain the raw material mixture ), with respect to the total amount of cesium 10 ^{−3 to} 25 mol% of europium is present, and in a more preferred example, there is an amount of europium in the range of 10 ⁻³ to 10 mol% with respect to the total amount of cesium.

Furthermore, according to the method of the present invention, the raw material mixture is present only in one crucible, and 10 ^{−3 to 5} mol% of europium is present in the raw material mixture with respect to the total amount of cesium, and more preferably in the raw material mixture. 10 ⁻³ to ³ mol% of europium is present with respect to the amount of cesium.

In another example of the method of the present invention, the raw material mixture is present in at least two crucibles, and in the raw material mixture of at least one crucible, 10 ^{−3 to} 80 mol% of europium is present relative to the total amount of cesium.

  The binderless phosphor screen according to the invention contains a CsX: Eu phosphor prepared according to the method example as described above.

  In accordance with the present invention, a method of manufacturing a binder-free phosphor screen or panel provides a CsX: Eu phosphor produced by the phosphor production example as described above, from physical vapor deposition, chemical vapor deposition and atomization techniques. Depositing said phosphor on a support by a method selected from the group consisting of:

Furthermore, according to the invention, a phosphor without binder on a support containing a CsX: Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br, Cl and combinations thereof. A method of manufacturing a body screen or panel is described, wherein the method is Cs _x Eu _y X ′ _{x + αy} (where X ′ is a halide selected from the group consisting of Cl, Br and I and combinations thereof; A precursor compound or a combination of precursor compounds with /y>0.25, α ≧ 2 and a number of heatable containers of CsX with the support (for example to change the vacuum from 10 ⁻⁴ mbar to 1 mbar) To) a deposition chamber evacuated to 1 mbar or less, and then add an inert gas (such as Ar) to it, and further physical vapor deposition Wherein on the support by a method selected from the group consisting of evaporation and atomization techniques CsX: as Eu and a composition of _{Cs x Eu y X 'x +} 3y or _Cs x _Eu y _X' wherein precursor compound having _{x + 2y,} or precursor compound The combination is such that a CsX: Eu phosphor (wherein Eu is present as a dopant in an amount of 10 ^{−5 to 5} mol%, in another example 10 ^{−3 to 5} mol%) is formed on the support. The process of vapor-depositing is included.

The present invention for making a phosphor screen or panel on a support containing a CsX: Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br, Cl and combinations thereof. in the process according to the method _Cs x _Eu y X as compositional _{'x + αy} (where, X' is a halide selected from the group consisting of Cl, Br and I and combinations thereof, x / y> 0.25 , Α ≧ 2 (optionally α ≦ 3), and a heatable container containing a precursor compound or a combination of precursor compounds and a mixture of CsX, together with the support, into a deposition chamber evacuated to 1 mbar or less, As the CsX: Eu and composition on the support by a method selected from the group consisting of physical vapor deposition, chemical vapor deposition and atomization techniques s including _x Eu _y X _'depositing a combination of the precursor compound or precursor compound having _{x + .alpha.y.}

In a particularly preferred example according to the invention, only CsX is present in one crucible, while in the other (second) crucible Cs _x Eu _y X ′ _{x + αy} is optionally provided in the presence of CsX. Even more preferred CsBr is present in one crucible in the example, while the second _Cs x _Eu in the crucible _y Br _{x +} αy (however, x / y> 0.25, α ≧ 2) is optionally different amounts of CsBr Exists in the presence.

In a further particularly preferred embodiment according to the present invention CsX in one crucible _'exist in the presence of _{x + .alpha.y,} whereas in another (second) crucible _{Cs x Eu y X' Cs x} Eu y X is _{x + .alpha.y} given. In an even more preferred example, CsBr and Cs _x Eu _y Br _{x + αy} (where x / y> 0.25, α ≧ 2) are present in one crucible, and Cs _x Eu _y Br _{x + αy} is given in the second crucible. It is done.

Further in accordance with the present invention, a method for recording and reproducing an image of an object produced by high energy radiation is disclosed, said method comprising the following steps as a continuous process:
- exposing the image storage panel in an X-ray radiation (the panel includes a CsX stimulable phosphor, X represents a halide selected from the group consisting of Br, Cl and combinations thereof, Eu is 10 ^-3 to Present as a dopant in an amount of 5 mol%, the phosphor is produced according to the above method),
-Stimulating said panel with radiation having a wavelength between 500 nm and 1100 nm, thereby emitting stimulated radiation;
-Collect the stimulated radiation.

Further in accordance with the present invention, a method for recording and reproducing an image of an object produced by high energy radiation is disclosed, said method comprising the following steps as a continuous process:
-Exposing a binderless phosphor screen as previously disclosed with X-ray radiation;
-Stimulating said panel with radiation having a wavelength between 500 nm and 1100 nm, thereby emitting stimulated radiation;
-Collect the stimulated radiation.

First, the trivalent europium derivative is isolated and dried, and the dried trivalent compound is reduced to obtain the divalent form of europium, and the europium salt (present in an amount of less than 10 mol%) is converted into CsBr salt (from 90 mol%). In contrast to the conditions that take many precautions to homogenize), the activator or dopant exists as a stable divalent europium, embedded in CsBr as a matrix component, and together with a stable ternary An intermediate complex is formed, where the formation of the complex and the formation of bromine (Br ₂ ) shifts the equilibrium towards the presence of divalent europium as a dopant or activator ion.

  The term “stable” here reflects not only “presence as oxidation-resistant divalent europium against air oxygen or other oxidants” but also resistance to moisture, such as ammonium bromide or HBr gas. Does not contain any halide.

Particularly _{Cs x Eu y X 'x +} αy as stable complex allows for homogeneous melt when mixed together with CsBr, put together in a crucible for evaporation purposes: Until 600 ° C. partial melting Things are still observed. The first melting point observed is in the range of the eutectic composition. It is clear that higher temperatures are required to melt the mixture together, and once melting begins, the melt is formed in a homogeneous manner without the formation of different phases and without the occurrence of spouts or swaying. It is. Furthermore, it is clear that this robust system as given in the present invention shows advantages over an evaporation system using one and two “boats” or “crucibles”. This is because there is no longer any compatible phase with different activator precursors and main components.

Experimental evidence for the purity of the stable ternary intermediate precursor complex was found by thermographic analysis. Furthermore, embedding CsBr with EuBr ₂ in the matrix clearly reduces its hygroscopicity.

The advantages associated with the present invention as described above are clearly associated with the stabilization of the compounds essential in the production process of the desired CsBr: Eu phosphor, the solid particles being processed at temperatures above 400 ° C. _Then, even is held in a state in which the eutectic composition has been buffered against _{Cs x Eu y X 'x +} αy precursors and mixtures major salts as CsBr.

A reasonable interpretation of the observed phenomenon is clearly associated with the presence of solid nuclei particles that act as nuclei controlling evaporation within the 585-675 ° C range and further up to 700 ° C. Interpretation of the signal in the XRD spectrum shows a very high probability of perovskite-like CsEuBr ₃ in addition to Cs ₂ EuBr ₄ as a divalent europium precursor when X ′ is Br.

  Thus, the “buffered state” described above ensures a constant composition of the deposited CsBr: Eu.

  While the invention will be described below in connection with its preferred examples, it will be understood that it is not intended to limit the invention to those examples.

1. Production of activator element precursor Cs _x Eu _y Br _z :
Different amounts of EuBr ₃ and CsBr were weighed to produce a precursor (EUBLA). After homogenizing the mixture, deionized water was added until a clear solution was formed. The solution was added to a ROTAVAP® unit in a glass vat placed in a triethylene glycol bath and heated to 100 ° C. under reduced pressure (50 mbar end) until the solution was dried and colored from white to yellow.

  Drying was then continued under reduced pressure at 150 ° C. for 8 hours. The dried compound was carefully weighed after cooling and stored in a glove box under inert gas (nitrogen).

Table 1 below summarizes the data of the different experiments, which were obtained by the number of moles of EuBr ₃ and CsBr, the ratio of Eu to the total amount of Eu + CsBr, the net weight obtained, the drying time, and the procedure given previously. Gives the number of moles of water still present in the powder mixture.

  From Table 1 below it can be concluded that only less than 0.1 mol of water present as "crystal water" is incorporated into the crystals of the crystal mixture thus obtained.

2. Combustion of activator element precursor Cs _x Eu _y Br _z :
In these experiments, 50 g of precursor powder was processed in an oven under nitrogen (1.5 l / min) and after 15 minutes the combustion procedure was started as summarized in Table 2. In Table 2, the combustion conditions were given in addition to the number of moles of CsBr per mole, the number of moles of EuBr ₃ per mole and the number of moles of weight loss equivalent to the loss of bromine for divalent Eu and trivalent Eu.

Table 2 shows the results obtained from CsBr / EuBr ₂ binary intermediate compounds at different combustion conditions.

Table precursor compound obtained from the weight balance of the 2 by combustion CsBr / EuBr ₂ binary actually corresponding it and thus the resulting precursor can be concluded that a _{Cs x} EuBr _{2 +} x. Similar results could be obtained for any ratio of intermediate compounds as previously obtained for the 70/30 molar ratio (further experiments performed were 90/10, 80/20, 60 / Made to a ratio of 40 and 50/50). From Table 2, there is a loss when CsBr evaporates at a high temperature of 600 ° C. The resulting weight loss is clearly equivalent to the loss of bromine in the reduction step where EuBr ₃ is reduced to EuBr ₂ and Br is lost.

In Table 3, summarized, melting temperature and weight loss% between 100 ° C.-200 ° C. (thermogravimetric analysis (TGA) and differential scanning calorimetry) for compounds obtained after burning in different ratios of CsBr and EuBr ₃ precursor mixtures. Meter (measured by DSC).

From Table 3, it can be concluded that the precursor composition obtained after combustion is not hygroscopic if compared to EuBr ₃ and EuBr ₂ compounds. At low temperatures, no weight gain was measured. If compared with CsBr / EuOBr _system, Cs _x EuBr _{2 +} x precursor gives better melting and evaporation behavior with CsBr. The optimized evaporation environment should be determined experimentally.

3. From the XRD spectrum of the Cs _x EuBr _{2 + x} precursor (mixture burned at 400 ° C.) as produced on the properties of the activator element precursor Cs _x Eu _y Br _z by X-ray diffraction (XRD) , the burned Cs _x The “2θ” peak in the EuBr _{2 + x} precursor diffraction spectrum clearly shows that the peak as registered is similar to the known peak of CsSmBr ₃ and that only the extra peaks consistent with the CsBr and EuOBr impurities were found. Indicated. _Further, indicated _{EuBr 2, EuBr 3, Eu 3} O 4 is clearly a peak of Br, _Eu 2 _{O 3,} it does not appear, it is further evidence for clearly proven presence of _{Cs x} EuBr _{2 +} x precursor.

Thus, contrary to the prior art literature, a well-known precursor compound different from EuBr ₃ is clearly proven to be an excellent precursor suitable for use as starting material in the synthesis of CsBr: Eu phosphors. It was done. The presence of dopants or particular desired CsEuBr ₃ and _Cs 2 EuBr ₄ starting precursor raw materials as activator source was clearly proven by X-ray diffraction as suitable analytical techniques.

  As stated for the purposes of the present invention, no special precautions are required to avoid absorption of water by the raw material mixture of starting materials which is distinctly different from the synthesized CsBr: Eu phosphor composition, and CsBr : No drying process is required which consumes time during the synthesis of the Eu phosphor.

  While preferred examples of the invention have been described in detail, it will be apparent to those skilled in the art that many changes can be made therein without departing from the scope of the invention as defined in the claims.

Claims (10)

A method for producing CsX: Eu-stimulated phosphor, wherein X represents a halide selected from the group consisting of Br, Cl and combinations thereof, wherein:
Cs _x Eu _y X ′ _{x + αy} as composition (where x / y> 0.25, α ≧ 2, X ′ is a halide selected from the group consisting of Cl, Br and I and combinations thereof) A precursor compound or a combination of precursor compounds having CsX with
-Heating the mixture at a temperature of 450 ° C or higher;
-Cooling said mixture;
-Recovering the CsX: Eu phosphor if desired;
A method comprising the steps. The method according to claim 1, wherein 10 ^{−3 to} 25 mol% of europium is present in the raw material mixture with respect to the total amount of cesium. The method according to claim 1 or 2, wherein the raw material mixture is present only in one crucible, and 10 ^{-3 to 5} mol% of europium is present in the raw material mixture with respect to the total amount of cesium. The method according to claim 1 or 2, wherein the raw material mixture is present in at least two crucibles, and 10 ^{-3 to} 80 mol% of europium is present in the raw material mixture of at least one crucible with respect to the total amount of cesium.   5. A CsX: Eu phosphor produced according to the method of any of claims 1-4, wherein said phosphor on a support by a method selected from the group consisting of physical vapor deposition, chemical vapor deposition and atomization techniques. A method for producing a binder-free phosphor screen or panel comprising the step of depositing. Producing a binder-free phosphor screen or panel on a support containing CsX: Eu-stimulated phosphor, where X represents a halide selected from the group consisting of Br, Cl and combinations thereof A method for the method comprising:
-Cs _x Eu _y X ' _{x + αy} as composition (where X' is a halide selected from the group consisting of Cl, Br and I and combinations thereof, x / y> 0.25, α ≧ 2 A precursor compound or a combination of precursor compounds having) and a number of heatable containers containing CsX, together with the support, into a deposition chamber evacuated to 1 mbar or less, further adding an inert gas,
-Further depositing the CsX: Eu stimulable phosphor on the support by a method selected from the group consisting of physical vapor deposition, chemical vapor deposition and atomization techniques;
Including steps,
The combination of the precursor compound or precursor compounds with _{Cs x Eu y X 'x +} 3y or _{Cs x Eu y X' x +} 2y as composition, CsX on the support: Eu storage phosphor (where, Eu is ¹⁰ -5 5 mol % Present as a dopant) in a ratio to CsX. A method for producing a phosphor screen or panel on a support containing CsX: Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br, Cl and combinations thereof. And said method is:
-Cs _x Eu _y X ' _{x + αy} as composition (where X' is a halide selected from the group consisting of Cl, Br and I and combinations thereof, x / y> 0.25, α ≧ 2 And a plurality of heatable containers containing a precursor compound or a combination of precursor compounds having CsX and CsX together with the support in an evaporation chamber evacuated to 1 mbar or less,
-Further depositing the CsX: Eu stimulable phosphor on the support by a method selected from the group consisting of physical vapor deposition, chemical vapor deposition and atomization techniques;
A method comprising the steps. Claims CsBr is present in one crucible and Cs _x Eu _y Br _{x + αy} (where x / y> 0.25, α ≧ 2) is optionally present in the presence of another amount of CsBr in the second crucible. Item 8. The method according to Item 7. CsBr and _Cs in one crucible _{x Eu y} Br x ₊ αy (however, x / y> 0.25, α ≧ 2) is present, according to _{Cs x Eu y} Br x _{+ αy} given claim 7 in a second crucible the method of.   A binderless phosphor screen containing a CsX: Eu phosphor produced according to the method of any of claims 1-9.