NLS-Glossary

At axial damping, the standard calibrating plate is conducted to the axis of the active surface of the sensor.                                                                                                                 

are allowed EM stationary waves that exist along the optical cavity length whose electric field patterns are determined by the length L of the optical cavity, e.g. $𝑚 ( \frac{𝜆}{2n} ) =L$where λ is the free-space wavelength, n is the refractive index of the cavity medium and m is an integer, 1, 2, … Longitudinal modes of an optical cavity are normally associated with transverse modes of the cavity. Each transverse mode has many longitudinal modes.

is one of two integers that are normally used to characterize propagating modes in a step index fiber (or more generally in a cylindrical waveguide). It characterizes the azimuthal field distribution. In a step index fiber, there are 2l number of maxima in the light intensity around a circle center on the fiber axis.

distance on the optical axis between last active optical surface and the sensor when the object is at infinity. The value is only valid in paraxial optics, ie for objects close to the optical axis. Further off the optical axis, the focal distance of distant objects is affected by the spherical aberration.

The area surrounding a printed symbol, including the spaces and quiet zones. Also referred to as the Substrate.                                                                                                   

to reliably distinguish a target object from non-target objects. This can be done for nearly every color and surface of the object, and reflective backgrounds are ignored.
Photoelectric sensors with background suppression consist of a light emitter and several light receivers. By means of triangulation, the position of an object can be determined. Using this position, the switching distance can be set and the object thereby distinguished from the background.

Electromechanical background suppression, the receiver is mechanically aligned with an external adjusting screw such that only reflected light from the desired working range strikes the receiving diode.

Electronic background suppression, light reflected by the object strikes a certain point at the receiver line array. Reflected light is electronically evaluated at this particular point.