Patent ID: 11892438
Assignee: ASAHI KASEI MICRODEVICES CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 9:
10. The optical densitometer according to claim 1, wherein
in the first distance modification region, the distance from the light propagation portion gradually changes from a distance greater than a distance given by the following Expression (3) to a distance equal to or smaller than a distance given by the following Expression (4):, 3
          ⁢
          
            λ
            0
          
        
        
          2
          ⁢
          π
          ⁢
          
            
              
                n
                pro
                2
              
              -
              
                n
                gap
                2
              
            
          
        
      
    
    
      
        Expression
        ⁢
        
          
        
        ⁢
        
          (
          3
          )
        
      
    
  

where λ0 represents the average wavelength, in vacuum, of the light propagating through the core layer, npro represents the refractive index of the material forming the light propagation portion or the extension region, and ngap represents a refractive index of a material present in a portion sandwiched between the light propagation portion and the at least a portion of the diffraction grating portion, and, 3
          ⁢
          
            λ
            0
          
        
        
          2
          ⁢
          π
          ⁢
          
            
              
                n
                coup
                2
              
              -
              
                n
                mid
                2
              
            
          
        
      
    
    
      
        Expression
        ⁢
        
          
        
        ⁢
        
          (
          4
          ), where λ0 represents the average wavelength, in vacuum, of the light propagating through the core layer, ncoup represents the refractive index of the material forming the first optical coupling region or the second optical coupling region, and nmid represents the refractive index of the material present in the portion sandwiched between the first optical coupling region and the second optical coupling region.