Patent ID: 6842243

Claim:
A turbidity sensor for underwater measurements, comprising: a watertight housing; a light emitting diode; a first light focusing device for focusing a light emitted from the diode and passing the focused light into to-be-measured water; a second light focusing device for collecting at least one scattered light resulted form the focused light when passing the water; a photodiode for receiving the collected light thereby generating electronic signals; and an electronic board for processing the electronic signals, wherein said watertight housing has cavities for accommodating the first and second focusing devices therein respectively, said cavities are shaved cylindrically and tilted with a first angle relatively to an upper surface of said watertight housing which is placed below a water surface, the first and second focusing devices are transparent cylinders having a flat end tilting relatively to a cylinder axis with a second angle so as to be in parallel with the upper surface of the housing and another end facing away from the upper surface, and the first angle is equal to the second angle, and said another end is a spherical surface for focusing light beam.