Image Sensor Bias Field Layout for Dark Current Reduction

The sensing region is divided into multiple unit pixels, and the bias field region is segmented to be disposed along the edges of these unit pixels. This segmentation allows the bias field to be applied locally at each pixel boundary, effectively reducing dark current and improving photocharge detection efficiency without requiring a completely redesigned structure.

The bias field region is strategically positioned only along the edges of the sensing region where dark current generation is most problematic. By applying the bias voltage locally at these critical boundary areas rather than uniformly across the entire sensor, the patent reduces dark current and improves detection efficiency while minimizing the overall structural complexity and voltage requirements.

The bias voltage is applied only to the bias field region located at the edges of the sensing region, not to the entire sensor area. This localized voltage application creates electric fields only where needed to guide photocharges away from dark current-prone boundary areas, thereby improving detection efficiency while significantly reducing overall power consumption compared to full-sensor biasing.

Instead of applying bias voltage uniformly across the entire sensing region, the patent uses partial action by limiting the bias field to only the edge regions where dark current is generated. This partial application of voltage is sufficient to achieve the desired photocharge movement and dark current reduction without the excessive power consumption that would result from full-area biasing.