Rotary sensor for industry uses polarization of light for sensing

May 18, 2014
Researchers at Fraunhofer Institute for Integrated Circuits (IIS; Erlangen, Germany) have developed a new kind of rotary sensor that combines precision measurement with flexible handling, allowing it to be customized to specific measurement tasks.
A polarization sensor mounted on a test board measures the angle of polarization rotation. (Copyright Fraunhofer IIS)

Researchers at Fraunhofer Institute for Integrated Circuits (IIS; Erlangen, Germany) have developed a new kind of rotary sensor that combines precision measurement with flexible handling, allowing it to be customized to specific measurement tasks. The scientists will be presenting their prototype at the Sensor + Test trade show in Nürnberg, Germany from June 3 to 5, 2014 (Hall 12, Booth 12-537).

There are currently two types of rotation-angle sensors on the market, based on either magnetic or optical measuring principles. Magnetic sensors are durable and dirt resistant, giving them an advantage in harsh environments. They are, however not as precise as optical sensors (rotary encoders). These in turn are not very flexible to use, since they must be precisely mounted in a fixed position on the object being measured.

The Fraunhofer IIS device relies on light polarization; a polarizing film is attached to the test object (a drive shaft, for example) and light directed at it. A readout module is mounted in the beam of light; several wire-grid microstructures are arranged in a matrix on the sensor chip (these grids can be manufactured using standard CMOS techniques). The angular position of the shaft is calculated when the polarized light strikes the lattices.

"To obtain a definite measurement of the angular position of a shaft, we need at least three grids that are each structured in different directions," says Norbert Weber, group manager at the IIS. "Depending on the measuring task, we can also add further grids, thus adapting the chip to suit the specific requirements of customers while increasing measurement accuracy."

The design is not as precise as conventional optical sensors, but the Fraunhofer IIS sensor is significantly more robust and can be relatively flexibly positioned. "The chip does not even have to sit directly on the optical axis -- the only thing that matters is that it is located within the light beam," says Weber. Another advantage is that even if the shaft wobbles slightly, the results are not affected as long as the beam is wide enough.

Source: http://www.fraunhofer.de/en/press/research-news/2014/may/right-spin.html

Sponsored Recommendations

Melles Griot® XPLAN™ CCG Lens Series

March 19, 2024
IDEX Health & Science sets a new standard with our Melles Griot® XPLAN™ CCG Lens Series fluorescence microscope imaging systems. Access superior-quality optics with off-the-shelf...

Spatial Biology

March 19, 2024
Spatial Biology refers to the field that integrates spatial information into biological research, allowing for the study of biological systems in their native spatial context....

Custom-Engineered Optical Solutions for Your Application

March 19, 2024
We combine advanced optical design and manufacturing technology, with decades of experience in critical applications, to take you from first designs to ongoing marketplace success...

Semrock Optical Filters Resources

March 19, 2024
Looking for more information about Semrock optical filters? Explore sets by fluorophore, download the 2023 Semrock catalog and more.

Voice your opinion!

To join the conversation, and become an exclusive member of Laser Focus World, create an account today!