4-Color Pixel Image Sensor NIR Noise Reduction

The optical black pixel region is segmented into two distinct functional regions: a visible optical black pixel region for concealing visible color noise and an NIR optical black pixel region for compensating noise transfer to NIR pixels. This segmentation allows each region to specialize in addressing different aspects of the technical contradiction without interfering with each other's function.

Different regions of the optical black pixel structure are given different local qualities: the visible optical black pixel region uses a metal layer configuration optimized for visible light blocking, while the NIR optical black pixel region uses a different metal layer configuration optimized for NIR light blocking. This local quality differentiation enables each region to effectively address its specific noise compensation task.

The patent transitions from a single-layer metal structure to a multi-layer stacked structure extending in the vertical dimension. By adding layers in the thickness direction rather than expanding horizontally, the patent achieves improved black level maintenance and noise blocking while minimizing lateral space consumption. The stacked configuration of photodiodes, metal layers, color filters, and micro-lenses creates a vertical architecture that efficiently packs multiple functional elements.

The multi-layer structure serves multiple functions simultaneously: the metal layers block incident light to maintain black level, the color filters separate wavelengths, the micro-lenses focus light, and the stacked photodiodes capture different color channels. This multi-functionality reduces the need for separate dedicated components, effectively managing complexity by combining functions into a unified stacked architecture.