Ex parte WAGNER - Page 4

              Appeal No. 1997-1899                                                                                         
              Application No. 08/407,145                                                                                   

                            As indicated above, present polarizers as commercially available, do                           
                     not transmit the infrared components of light in a linear manner as compared                          
                     to other frequency components contained in the light beam. Hence, the                                 
                     blue-green filter serves to attenuate transmitted light components about the                          
                     near infra-red spectrum which are for example, emitted by foilage such as                             
                     grass, trees and so on. In this manner, the output light from the entire                              
                     arrangement depicted is indicative of nighttime conditions. By rotating the                           
                     plate 21 with respect to plates 20 and 22, one can thereby achieve a                                  
                     variation in the light directed to the night vision device and hence, by such                         
                     rotation one can simulate various nighttime conditions as starlight, overcast                         
                     moonlight, or direct moonlight and one can do so in any particular daylight                           
                     condition as from early dusk to noon day sunlight.                                                    

              (See Burbo at column 3, line 57 to column 4, line 13.)  Burbo clearly compensates for the                    
              variations in light for the entire day from dawn to dusk without the need for a variable filter              
              as the examiner maintains on page 6 of the answer.  Burbo states that the blue-green filter                  
              is to compensate for inherent problems induced by the use of the polarizers,  therefore,  in                 
              our view,  there would have been no motivation to vary this filter since this would negate the               
              needed compensation.                                                                                         
                     The examiner argues that the “combination of the static blue-green filter in addition                 
              to the polarization plates makes a mechanically alterable (through attenuation by the                        
              polarization plates) frequency filter (through the blue-green filter).”                                      
              (See supplemental answer at page 2.)  We disagree with the examiner as discussed                             
              above.   The examiner relies upon the Burbo at column 3, lines 14-27 which states:                           


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