Aug 25, 2025
Against the backdrop of continuous advancements in modern technology, electronic image sensors, as the core components of various digital imaging devices, are widely used in industrial cameras, digital cameras, surveillance systems, mobile phones, automotive auxiliary systems, and fields such as medical, biometric identification, and more. As the demands for image clarity, speed, and power consumption continue to rise, electronic image sensor technology is also continually evolving.
An electronic image sensor is a semiconductor device capable of converting optical images into electrical signals. By focusing external light onto the sensor’s image plane through an imaging lens, a two-dimensional light intensity distribution is formed. The photosensitive pixel array inside the sensor then converts this light intensity into analog or digital signals, completing the acquisition and processing of image information.
Currently, electronic image sensors are mainly divided into the following three categories:
CCD (Charge-Coupled Device)
CCD is a type of electronic image sensor with a long history, known for its high sensitivity, low noise, and high-quality imaging. It is widely used in high-end fields such as astronomical photography and professional video equipment. CCD transmits signals by coupling charges within the chip. While its imaging quality is excellent, its manufacturing cost is high, and it has relatively higher power consumption.
CMOS (Complementary Metal-Oxide Semiconductor)
CMOS is a rapidly emerging type of electronic image sensor in recent years. With its simple structure, low power consumption, high integration, and relatively low cost, it is suitable for portable devices such as mobile phones and web cameras. With advancements in manufacturing processes, the image quality of CMOS has gradually caught up with, or even partially surpassed, CCD, becoming the mainstream in the market.
CIS (Contact Image Sensor)
CIS is a type of electronic image sensor specifically used for scanners. It works by closely contacting the scanned object with an LED light source to complete image acquisition. Although CIS does not match CCD and CMOS in depth of field and resolution, its simple structure and low cost make it suitable for scanning flat documents.
The core working processes of electronic image sensors include light reception, conversion, and signal transmission:
Light reception: External scene light is focused on the sensor surface through the lens.
Photoelectric conversion: The light intensity received by each pixel is converted into the corresponding charge by a photodiode.
Signal reading and processing: CCD transmits charges to the output via a shift register, while CMOS directly converts them to voltage signals through internal circuits, then processes them to digital image signals via analog-to-digital conversion (ADC).
The number of pixels determines the image resolution; the more pixels an electronic image sensor contains, the finer the image it can reproduce.
With the development of emerging technologies such as AI vision, autonomous driving, and virtual reality, electronic image sensors are moving towards higher resolution, lower power consumption, higher dynamic range, and greater intelligence. CMOS, with its superior process compatibility and scalability, will play an increasingly important role in the future. As the “eyes” of digital imaging systems, electronic image sensors, with their diverse classifications and clear principles, have achieved deep integration and innovation in multiple technical fields. With continuous sensor technology advancements, we have reason to believe that future imaging devices will be smarter, more efficient, and more precise.
