Patent ID: 11940263
Assignee: TRINAMIX GMBH
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 14:
15. A method for determining a position of at least one object (114) by using at least one detector (112), the method comprising the following steps:
providing at least one transfer device (130), wherein the transfer device (130) has at least one focal length in response to the at least one incident light beam propagating from the object (114) to the detector (112), wherein the transfer device (130) has at least one optical axis (142);
providing at least one illumination source (144) adapted to generate at least one light beam (146) for illuminating the object (114), wherein the illumination source (144) is displaced from the optical axis (142) by a distance BL, wherein the illumination source (144) has a geometrical extend G in a range 3.10−4 mm2·sr≤G≤3.3 mm2·sr; wherein the illumination source (144) comprises at least one optical sender fiber (118) for illuminating the object (114);
providing at least one first optical receiving fiber (120, 122) and at least one second optical receiving fiber (122, 124), wherein each of the optical receiving fibers (120, 122, 124) comprises at least one cladding (136) and at least one core (134), wherein the first optical receiving fiber (120, 122) has a core diameter of d1, wherein the second optical receiving fiber (120, 124) has a core diameter of d2, wherein a ratio d1/BL is in a range 0.000318≤d1/BL≤6.83, and wherein the ratio d2/BL is in the range 0.000318≤d2/BL≤6.83, wherein an entrance face of at least one of the optical receiving fibers (120, 126, 124) is arranged such that a variance over distance dependence of the combined signal is maximal, wherein the entrance face of at least one of the optical receiving fibers (120, 126, 124) is positioned as such that a combined signal Qfar at large object distances and a combined signal Qclose at small object distances have a maximum variation, Q
      far
     
     
      Q
      
       c
       ⁢
       l
       ⁢
       o
       ⁢
       s
       ⁢
       e
      
     
    
    ≈
    
     
      
       
        r
        Coc
        
         Object
         ,
         close
        
       
       (
       
        
         z
         O
        
        ,
        
         Z
         s
        
        ,
        
         Z
         i
        
       
       )
      
      2
     
     
      
       
        r
        Coc
        
         Object
         ,
         far
        
       
       (
       
        
         z
         O
        
        ,
        
         Z
         s
        
        ,
        
         Z
         i
        
       
       )
      
      2
     
    
   
   →
   max
  
  ,
 

wherein rCocObject,close is a radius of the circle of confusion at small object distances and rCocObject,far is a radius of the circle of confusion at large object distances, wherein zO is a detectable distance range between the entrance face of at least one of the optical receiving fibers (120, 126, 124) and the object, zs is a distance between the transfer device (130) and the entrance face of at least one of the optical receiving fibers (120, 126, 124) and zi is a position of the focused image behind the transfer device (130), which depends on the position of the object zo;
providing at least two optical sensors (126, 128), wherein at least one first optical sensor (126) is arranged at an exit end of the first optical receiving fiber (120, 122) and at least one second optical sensor is arranged at an exit end of the second optical receiving fiber (120, 124), wherein each optical sensor (126, 128) has at least one light sensitive area (148), wherein each optical sensor (126, 128) is designed to generate at least one sensor signal in response to an illumination of its respective light-sensitive area (148) by the light beam generated by the object (114) having passed through the respective optical receiving fiber (120, 122, 124);
illuminating the light-sensitive area (148) of at least one of the optical sensors (126, 128) with the light beam having passed through the first optical receiving fiber (120, 122) and illuminating the light-sensitive area (148) of the other one of the optical sensors (126, 128) with the light beam having passed through the second optical receiving fiber (120, 124), wherein, thereby, each of the light-sensitive areas (148) generates at least one sensor signal; and
evaluating the sensor signals, thereby, determining at least one longitudinal coordinate z of the object (114), wherein the evaluating comprises deriving a combined signal Q of the sensor signals.