Optical Sensor for Measuring the Concentration of Ethanol in Aqueous Solutions

A variant of an optoelectronic sensor for measuring the concentration of ethanol in an aqueous solution is proposed. The dependence of the refractive index on the concentration of ethanol in an aqueous solution is used. The refractive index is calculated by the reflection coefficient from the interface with the measured solution. A method for calculating the profile of a plastic collimating optical lens for this sensor is proposed. The measurement accuracy is improved by using a reference channel and controlling the power of the radiation source.