In the development of image sensor chips, what is "Saturation capacity”

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What is "Saturation capacity"?

In image sensor chip research and development, “Saturation capacity” refers to the maximum light signal intensity that a sensor can process. In other words, it indicates the limit value that the sensor can accommodate or process when exposed to very intense illumination.

Simply put, Saturation capacity is like the “saturation point” of the sensor. When the intensity of the light signal exceeds this saturation point, the sensor can no longer effectively process stronger light, which may cause overexposure or distortion in the image.

The purpose of measuring Saturation capacity is to ensure that the sensor can process light signals of various intensities under different lighting conditions and avoid distortion or saturation under high light intensity conditions. R&D engineers typically evaluate the sensor’s response under different lighting conditions to ensure its Saturation capacity is sufficient to cope with various lighting scenarios that may be encountered in real-world applications.

How "Saturation capacity" works

Light signal conversion: The basic function of a sensor is to convert light signals into electrical signals. When light shines on the sensor, the light signal is converted into an electrical signal by the photosensitive element – this is the first step in image capture by the sensor.
Electrical signal saturation: Saturation capacity involves the maximum light signal intensity that the sensor can process. When the intensity of the light signal reaches or exceeds the sensor’s limit value, the sensor’s electrical signal becomes saturated, reaching its maximum processing capacity.
Effect of saturation: When the sensor is saturated, it can no longer effectively distinguish between different brightness levels of light. This can cause overexposed areas in the image, loss of detail, and possible color distortion around saturated areas.
Measuring Saturation capacity: The process of measuring Saturation capacity usually involves exposing the sensor to light of different brightness levels and observing changes in its electrical signal. The limit value where the electrical signal can no longer increase is the Saturation capacity.

In summary, the working principle of Saturation capacity is that the sensor has an upper limit on processing light signals – exceeding this limit causes sensor saturation and image distortion. Measuring Saturation capacity helps ensure the sensor can cope with various lighting conditions and avoid issues when images are captured in high light environments.