Optical encoders, also known as optical rotary encoders, are characterized by a very high position accuracy and repeatability as well as a very high signal quality. Moreover, they are not sensitive to magnetic interference and offer a significantly higher resolution than magnetic encoders.
In optical encoders, a code disc with a measuring element attached to the shaft of the motor is used. A distinction is made here between reflective and transmissive optical encoders.
Reflective optical encoders
With reflective optical encoders, the light from an LED is reflected back to the code disc by a reflective surface and collected by photodetectors. Reflective optical encoders are especially compact since the LED, the photodetectors and the electronics can be mounted on the same circuit board or even on the same chip. For these reasons, FAULHABER primarily uses reflective optical encoders.
Transmissive optical encoders
Transmissive optical encoders make use of the transmitted light process. Here, the light from the LED passes through slits in the code disc and is collected by photodetectors on the other side of the code disc.