Phosphor screen and imaging assembly with poly(lactic acid) support

Abstract

A phosphor screen comprises an inorganic phosphor capable of absorbing X-rays and emitting electromagnetic radiation having a wavelength greater than 300 nm. The phosphor is disposed on a support that has a reflective substrate comprising a continuous poly(lactic acid) first phase and a second phase dispersed within the continuous poly(lactic acid) first phase. The second phase contains microvoids that in turn contain barium sulfate particles. This support provides improved reflectivity particularly at shorter wavelengths.

1 - 21 . (canceled)  
   
   
       22 . A flexible film comprising at least one layer comprising a continuous poly(lactic acid) first phase and a second phase dispersed within said continuous poly(lactic acid) first phase, said second phase comprised of microvoids containing inorganic particles.  
   
   
       23 . The flexible film of  claim 22  wherein said microvoids comprise barium sulfate particles.  
   
   
       24 . The flexible film of  claim 22  wherein said microvoids occupy from about 35 to about 60% (by volume) of said reflective substrate and said inorganic particles have an average size of from about 0.6 to about 2 mμ and comprise from about 23 to about 65 weight % of total substrate weight.  
   
   
       25 . The flexible film of  claim 22  having a dry thickness of from about 30 to about 120 mμ.  
   
   
       26 . The flexible film of  claim 22  wherein said poly(lactic acid) first phase is a biaxially oriented poly(lactic acid).  
   
   
       27 . The flexible film of  claim 22  wherein the ratio of the reflective index of said poly(lactic acid) first phase to said second phase is from about 1.4:1 to about 1.6:1.  
   
   
       28 . The flexible film of  claim 22  that is capable of reflecting at least 90% of incident radiation having a wavelength of from about 300 to about 700 nm.  
   
   
       29 . The flexible film of  claim 22  having a dry thickness of from about 75 to about 400 μm.  
   
   
       30 . The flexible film of  claim 22  wherein said poly(lactic acid) first phase is composed of at least 75% by weight of poly(L-lactic acid).  
   
   
       31 . The flexible film of  claim 22  further comprising a transparent protective layer disposed thereover.  
   
   
       32 . The flexible film of  claim 22  further comprising a microvoided polymer layer that is free of barium sulfate and arranged directly adjacent thereto.  
   
   
       33 . The flexible film of  claim 32  wherein said microvoided polymer layer has a dry thickness of from about 30 to about 120 μm.  
   
   
       34 . The flexible film of  claim 32  wherein said microvoided polymer layer is a stretched polyester layer.  
   
   
       35 . The flexible film of  claim 32  wherein said microvoided polymer layer comprises organic particles in the microvoids.