Overview of General Technologies for Image Sensors

technical dimension

Key content

Explanation/Technical Points

core principle

photoelectric conversion

By using photosensitive elements (mainly photodiodes) to convert received photons into electrons, an electrical signal is formed.

mainstream technology

CMOS vs. CCD

CMOS image sensors have become the absolute mainstream in the market due to their high integration, low power consumption, and cost advantages; CCD is mainly used in professional fields with special requirements for image quality.

Process structure

FSI, BSI, Stacked

This is the technological evolution route: front illuminated → back illuminated → stacked. Stacking is currently the mainstream direction, which separates and stacks pixel layers and logic circuit layers, significantly improving performance and reducing size.

shutter type

Rolling shutter shutter vs. global shutter

Roller shutter with line by line exposure has low cost, but it may cause deformation when shooting moving objects; The global shutter simultaneously exposes the entire image without distortion, but the pixel structure is more complex. Modern advanced sensors can integrate two modes.

key parameters

Pixel, pixel size, optical size

The "impossible triangle" is composed of high pixel, large size (pixel size and optical size), and low cost, which need to be balanced according to the application. Other important parameters include dynamic range, signal-to-noise ratio, frame rate, etc.

Manufacturing and Packaging

Wafer stacking, special processes

It involves unique processes such as deep photodiode molding, pixel isolation, and color filter arrays. The packaging forms such as CSP, COB, etc. affect the final module size and performance.