Patent ID: 8604455

Claim:
An optical sensor array ( 10 ) detecting a first liquid medium in a second liquid medium by reflecting an emitted light beam at a given wavelength at a reflecting surface ( 30 ), comprising a light source ( 5 ) and an associated first receiver ( 6 ), comprising: two glass rod lenses ( 20 ) being configured parallel to each other the first glass rod lens ( 20 a ) having a polished angular boundary surface ( 21 a ) with respect to an optical axis thereof; the reflecting surface ( 30 A) being situated opposite the glass rod lenses ( 20 a , 20 b ); the light source being allocated to the first glass rod lens ( 20 a ); the first receiver being allocated to the second glass rod lens ( 20 b ); and wherein a light beam leaving the first glass rod lens ( 20 a ) through the boundary surface ( 21 a ) is affected by light refraction.