Phosphor panel with good humidity resistance

Abstract

A phosphor panel with a protective coating divided in at least two layers: a layer A, being closest to said phosphor layer and a layer B farther away from said phosphor layer wherein the layer A has a lower water vapour permeability coefficient than the layer B. Layer A has a water vapour permeability coefficient, P, so that 0 ≤ P ≤ 1 × 10 - 11 ⁢ cm 3 ⁡ ( STP ) · cm cm 2 · s · Pa .

1 . A phosphor panel comprising a phosphor layer and a protective layer, wherein the phosphor layer has a main surface and edges, characterized in that said protective layer is divided in at least two layers: 
 a layer A, being closest to said phosphor layer and    a layer B farther away from said phosphor layer;    and wherein said layer A has a lower water vapour permeability coefficient than said layer B.    
     
     
         2 . A phosphor panel according to  claim 1 , wherein said layer A has a water vapour permeability coefficient, P, so that  
       
         
           
             
               0 
               ≤ 
               P 
               ≤ 
               
                 1 
                 × 
                 
                   10 
                   
                     - 
                     11 
                   
                 
                 ⁢ 
                 
                   
                     
                       
                         
                           cm 
                           3 
                         
                         ⁡ 
                         
                           ( 
                           STP 
                           ) 
                         
                       
                       · 
                       cm 
                     
                     
                       
                         cm 
                         2 
                       
                       · 
                       s 
                       · 
                       Pa 
                     
                   
                   . 
                 
               
             
           
         
       
     
     
         3 . A phosphor panel according to  claim 1 , wherein said layer B is an outermost layer and has a thickness, t, and looses in a Taber abrasion test (sandpaper P220, load 250 g, 500 cycles) at most 25% of said thickness t.  
     
     
         4 . A phosphor panel according to  claim 1 , wherein said layer A is adjacent to the said phosphor layer and contains a layer of parylene.  
     
     
         5 . A phosphor panel according to  claim 4 , wherein said parylene is selected from the group consisting of parylene C, parylene D and parylene HT.  
     
     
         6 . A phosphor panel according to  claim 1 , wherein said layer A has a thickness in the range between 0.05 μm and 15 μm.  
     
     
         7 . A phosphor panel according to  claim 1 , wherein said layer B is a radiation cured polymeric layer.  
     
     
         8 . A phosphor panel according to  claim 2 , wherein said layer A is adjacent to said phosphor layer and contains a layer of parylene.  
     
     
         9 . A phosphor panel according to  claim 6 , wherein said parylene is selected from the group consisting of parylene C, parylene D and parylene HT.  
     
     
         10 . A phosphor panel according to  claim 2 , wherein said layer A has a thickness in the range between 0.05 μm and 15 μm.  
     
     
         11 . A phosphor panel according to claims  2 , wherein said layer B is a radiation cured polymeric layer.  
     
     
         12 . A phosphor panel according to  claim 3 , wherein said layer A is adjacent to the said phosphor layer and contains a layer of parylene.  
     
     
         13 . A phosphor panel according to  claim 8 , wherein said parylene is selected from the group consisting of parylene C, parylene D and parylene HT.  
     
     
         14 . A phosphor panel according to  claim 3  wherein said layer A has a thickness in the range between 0.05 μm and 15 μm.  
     
     
         15 . A phosphor panel according to  claim 3 , wherein said layer B is a radiation cured polymeric layer.  
     
     
         16 . A phosphor panel according to  claim 1 , wherein said phosphor layer is a photostimulable phosphor layer.  
     
     
         17 . A phosphor panel according to  claim 16 , wherein said panel comprises a binderless photostimulable phosphor layer.  
     
     
         18 . A phosphor panel according to  claim 17 , wherein said binderless photostimulable phosphor layer contains a CsX:Eu stimulable phosphor, wherein X represents a halide selected from the group consisting of Br and Cl.  
     
     
         19 . A method for the preparation of a binderless phosphor panel comprising the steps of: 
 providing a support,    vapour depositing a CsX:Eu phosphor, wherein X representing a halide selected from the group consisting of Br and Cl, thereby forming a binderless phosphor layer on the said support,    applying a layer of parylene on the said binderless phosphor layer by chemical vapour deposition, thereby forming a layer A;    applying a radiation curable solution on top of the said layer A; and    curing said panel by UV exposure, thereby forming layer B.    
     
     
         20 . A method according to  claim 19 , further including a step of applying an edge reinforcement.  
     
     
         21 . A method for the preparation of a binderless phosphor panel comprising the steps of 
 providing a support,    vapour depositing a CsX:Eu phosphor, wherein X represents a halide selected from the group consisting of Br and Cl, thereby forming a binderless phosphor layer on the said support,    applying a layer of parylene on the said binderless phosphor layer by chemical vapour deposition, forming a layer A;    applying a radiation curable solution on top of the said layer A; and    curing said panel by electron beam exposure, thereby forming layer B.    
     
     
         22 . A method according to  claim 21 , further including a step of applying an edge reinforcement.