OPT - Optical Level Switch

KOBOLD OPT optical level switches for clear or translucent liquids are perfect for serving as a level limit detector for various process liquids. 

Its small geometry enables a very low switching hysteresis. 

The optical design is free of any moving parts, delivering increased reliability. 

This optical liquid level switch is completely self-contained; both the LED light source and the photodetector are housed behind the same lens.

The OPT consists of a hollow hemispherical lens, in which the infrared diodes are fitted as a transmitter and as a receiver with semiconductor switch. 

When the sensor lens is dry, all of the infrared light is reflected from the surface of the hemisphere onto the receiver. 

As soon as the sensor lens is covered with liquid, the refractive index on the boundary layer changes and most of the light then escapes into the liquid. 

Less light reaches the receiver, which initiates the switching function.