Optical Encoders with Talbot Imaging

Why Talbot Imaging is Used in Interferential Optical Encoders

Encoders are used in closed loop systems to measure the position of a load. In many applications, such as surgical robotics and satellite communication devices, high resolution, high accuracy and lower power consumption are key requirements for an encoder.

Talbot Imaging enables high resolution and high accuracy

Interferential optical encoders that utilize talbot imaging allow for very high resolution and accuracy. Talbot imaging is a phenomenon that occurs when monochromatic plane waves are incident on a grating, and spherical wavefronts are created. These wavefronts then interfere to create an exact replica of the grating (same pitch and phase) at the talbot distance. The talbot image is relatively large and can be filtered to produce a pure sinusoidal wave, therefore very high resolution can be achieved while allowing for wide alignment tolerances. In addition to the resolution and accuracy, talbot imaging interferential encoders do not require additional components like filtering optics, making it a smaller package than other encoders.

Lasers Enable Lower Power Consumption

Talbot Imaging based Interferential encoders utilize a laser as the light source rather than a LED. This means that the encoder has lower power consumption and runs cooler than other LED-based encoders.