Method of vaporization of phosphor precursor raw materials
In a method of preparing a storage phosphor layer on a support by vapor deposition from a crucible unit by heating as phosphor precursor raw materials a matrix component and an activator component or a precursor component thereof, wherein said crucible unit comprises at least a bottom and surrounding side walls as a crucible for phosphor precursor raw materials present in said crucible in liquid form, wherein said crucible unit further comprises at least a chimney as part of the crucible unit and a slit allowing phosphor precursor raw materials to escape in vaporized form from said crucible unit in order to deposit it as a phosphor layer onto said support, the step of heating said precursor raw materials in the crucible in liquid form proceeds up to a temperature T 1 and the step of heating said precursor raw materials in vaporized form in said chimney, proceeds up to a temperature T 2 , characterized in that a positive difference in temperature [T 2 −T 1 ] is maintained.
1 . Method of preparing a storage phosphor layer on a support by vapor deposition from a crucible unit by heating as phosphor precursor raw materials a matrix component and an activator component or a precursor component thereof, wherein said crucible unit comprises at least a bottom and surrounding side walls as a crucible for phosphor precursor raw materials present in said crucible in liquid form, wherein said crucible unit further comprises at least a chimney as part of the crucible unit and a slit allowing phosphor precursor raw materials to escape in vaporized form from said crucible unit in order to deposit it as a phosphor layer onto said support, wherein the step of heating said precursor raw materials in the crucible in liquid form proceeds up to a temperature T 1 and wherein the step of heating said precursor raw materials in vaporized form in said chimney, proceeds up to a temperature T 2 , characterized in that a positive difference in temperature [T 2 −T 1 ] is maintained.
2 . Method according to claim 1 , wherein said temperatures T 1 and T 2 are attained by radiation heating, resistive heating or a combination of radiation heating and resistive heating.
3 . Method according to claim 1 , wherein said temperatures are controlled by means of thermo-couples.
4 . Method according to claim 2 , wherein said temperatures are controlled by means of thermo-couples.
5 . Method according to claim 1 , wherein said temperatures are controlled and steered by means of thermo-couples.
6 . Method according to claim 2 , wherein said temperatures are controlled and steered by means of thermo-couples.
7 . Method according to claim 5 , wherein said temperatures are steered by means of thermo-couples via a back-coupling mechanism.
8 . Method according to claim 6 , wherein said temperatures are steered by means of thermo-couples via a back-coupling mechanism.
9 . Method according to claim 1 , wherein a set of coupled thermo-couples is mounted in the raw materials, covering part of the bottom of the said crucible.
10 . Method according to claim 1 , wherein a set of coupled thermo-couples is present at the outside of the crucible, in contact with the bottom of said crucible in order to measure and steer temperature T 1 .
11 . Method according to claim 1 , wherein a set of coupled thermo-couples is present in the vaporized raw materials in the said chimney in order to measure and steer temperature T 2 .
12 . Method according to claim 1 , wherein CsX is a matrix component and EuX 2 , EuX 3 , EuOX or a mixture thereof are activator components, X representing Cl, Br, I or a combination thereof.
13 . Method according to claim 1 , wherein Cs x Eu y X′ (x+αy) is an activator precursor material, wherein x, y and α are integers, wherein x/y is more than 0.25 and wherein a is at least 2 and wherein X′ represents Cl, Br, I or a combination thereof.
14 . Method according to claim 1 , wherein said storage phosphor is CsBr:Eu.
15 . Method according to claim 1 , wherein temperature T 1 is higher than 640° C.
16 . Method according to claim 1 , wherein temperature T 2 is higher than 640° C.
17 . Method according to claim 1 , wherein a difference in temperature [T 2 −T 1 ] of at least 80° C. is maintained.
18 . Method according to claim 1 , wherein said support is composed of glass, a ceramic material, a polymeric material or a metal.
19 . Method according to claim 1 , wherein said vapor deposition proceeds in a batch process.
20 . Method according to claim 1 , wherein said vapor deposition proceeds in a continuous process.▪