sensorränden

Sensorranden is the outer boundary of the active sensing area in a sensor. In solid-state devices such as CCDs and CMOS image sensors, sensorranden marks where the electronically active region ends and the inactive perimeter or edge of the device begins. The edge is influenced by how the electric fields are terminated, how closely the peripheral pixels are wired to readout electronics, and the coatings and passivation applied at the periphery.

Edge effects are a common characteristic of sensorranden. Near the boundary, the sensor often exhibits reduced sensitivity, nonuniform response, and, in optical sensors, shading or vignetting that can complicate flat-field corrections. These effects arise from the geometry of the sensor, variations in fill factor between edge and central pixels, charge collection inefficiencies, and changes in electric field lines at the edge.

To mitigate sensorranden effects, manufacturers employ several techniques. Guard rings and deep diffusions help terminate electric fields and collect stray charges. Trench isolation and careful edge-passivation reduce leakage currents and cross-talk. Edge design often aims to maintain a similar electrical environment for peripheral pixels as for central ones, and calibration procedures such as flat-field correction are used to compensate residual nonuniformities. In large-area tiling, sensorranden regions may be avoided in data analysis or corrected for during mosaicking.

The term is device- and application-specific; its exact definition can vary with sensor architecture, fabrication process, and the intended use of the sensor.