Long wave infrared imaging polarimeter, and method of assembly

Abstract

A long wave infrared imaging polarimeter (LWIP) is disclosed including a pixilated polarizing array (PPA) in close proximity to a microbolometer focal plane array (MFPA), along with an alignment engine for aligning and bonding the PPA and MFPA and method for assembly.

We claim: 
     
         1 . An LWIP comprising a PPA and an MFPA, the PPA comprising a substrate and pixels for receiving energy from a source and the MFPA comprising a substrate and pixels, the PPA affixed to and parallel with the MFPA, and the PPA and MFPA aligned so that the PPA pixels correspond one-to-one to the MFPA pixels and the PPA pixels transmit energy from the source to the corresponding MFPA pixels. 
     
     
         2 . The LWIP as in  claim 1 , wherein each of the PPA pixels comprises a wire grid. 
     
     
         3 . The LWIP as in  claim 2 , wherein each of the wire grid comprises wires which are substantially parallel. 
     
     
         4 . The LWIP as in  claim 3 , wherein each of the wire grids has an orientation of 0, 45, 90 or 135 degrees. 
     
     
         5 . The LWIP as in  claim 4 , wherein each of the 0 degree wire grids is adjacent to one of the 90 degree wire grids, and each of the 45 degree wire grids is adjacent to one of the 135 degree wire grids. 
     
     
         6 . The LWIP as in  claim 5 , wherein vertically correlated noise is removed by the following operations 
       
         
           
             
               
                 S 
                 1 
               
               = 
               
                 
                   
                     I 
                     0 
                   
                   - 
                   
                     I 
                     90 
                   
                 
                 
                   
                     I 
                     90 
                   
                   + 
                   
                     I 
                     0 
                   
                 
               
             
           
         
         
           
             
               
                 S 
                 2 
               
               = 
               
                 
                   
                     I 
                     45 
                   
                   - 
                   
                     I 
                     135 
                   
                 
                 
                   
                     I 
                     45 
                   
                   + 
                   
                     I 
                     135 
                   
                 
               
             
           
         
       
       where I 0  is the image formed with the 0 degree pixels, I 90  is the image formed with the 90 degree pixels, I 45  is the image formed with the 45 degree polarized pixels, and I 135  is the image formed with the 135 degree polarized pixels. 
     
     
         7 . The LWIP as in  claim 1 , the PPA further comprising an anti-reflective coating. 
     
     
         8 . The LWIP as in  claim 1 , wherein the PPA has a pitch which is substantially the same as the pitch of the MFPA. 
     
     
         9 . The LWIP as in  claim 1 , wherein the PPA and MFPA are secured so that the pixels of the PPA and MFPA are at a distance not exceeding approximately one half the pitch of the pixels. 
     
     
         10 . The LWIP as in  claim 1 , wherein the PPA pixels and the MFPA active areas have centers, and the PPA pixel centers and the MFPA pixel active areas are within a range of +/−2 microns. 
     
     
         11 . The LWIP as in  claim 1 , further comprising optics having an f/# of less than one. 
     
     
         12 . An alignment engine for aligning and bonding a PPA to an MFPA, said alignment engine having components capable of assuming an epoxy deposition position and also an alignment and bonding position, and said components comprising
 a. an epoxy deposition stage comprising a 3 axis stage, a needle mount having two ends, and a needle for depositing epoxy, the 3 axis stage connected to one end of the needle mount and the needle connected to the other end of the needle mount,   b. a PPA chuck actuator comprising a motor and a PPA chuck comprising a transparent disc,   c. an MFPA chuck actuator,   d. a downlooking camera mounted directly above the epoxy deposition,   e. a first sidelooking camera mounted to the side of, and at the same height as, the epoxy deposition position,   f. an LWD microscope and associated camera directly above the alignment and boding position and mounted on an LWD actuator   g. a second sidelooking camera mounted to the side of, and at the same height as, the alignment and bonding position,   h. a UV light for curing the epoxy,   such that when the transparent disc is in the line of sight of the LWD microscope and associated camera, and the PPA and the MFPA are properly aligned, they are bonded together by curing the epoxy with the UV light.