CMOS image sensor technology, initially developed at NASA's Jet Propulsion Laboratory (JPL) for space missions, is now extensively used in billions of devices globally, including cell phones.
From Space to Your Pocket: The Rise of CMOS Image Sensors
Development at JPL
In the 1980s, Charge Coupled Device (CCD) technology was the primary method for generating high-quality images in space science and other applications. Dr. Eric Fossum was hired by JPL in 1990 to advance CCD technology for interplanetary space missions. Instead, he pioneered the advancement of Complementary Metal-Oxide Semiconductor (CMOS) technology for this purpose.
Fossum developed the first CMOS active pixel image sensor by applying a technique commonly used for CCDs to CMOS sensors. This technique, called "intra-pixel charge transfer with correlated double sampling," enabled significant noise reduction in CMOS sensors. It achieved this by taking double measurements of a pixel's voltage (without and with light-generated charge) and subtracting the values to improve the signal-to-noise ratio.
Technical Advantages
CMOS sensors offered distinct advantages over their CCD predecessors:
- CCD Sensors: These convert light into electric charges, which are then transferred step-by-step to an amplifier. This process requires significant power and an efficient charge transfer mechanism.
- CMOS Sensors: A key innovation, CMOS sensors feature signal amplifiers within each pixel, allowing for direct signal reading. This design inherently requires less voltage to operate and significantly reduces issues like radiation susceptibility often associated with charge transfer in CCDs.
Commercialization and Global Adoption
Following its development, several companies collaborated with JPL to refine the technology. In 1995, Fossum and Dr. Sabrina Kemeny licensed the technology from CalTech and established Photobit to further develop CMOS sensors. Photobit focused on improving CMOS capabilities, reducing power requirements, and lowering manufacturing costs, paving the way for wider adoption.
CMOS cameras quickly found applications in early webcams and revolutionary medical "pill cams."
In 2001, Micron Technology acquired Photobit, dedicating additional resources to CMOS development. The rapid expansion of the cell phone industry proved to be a major catalyst, leading to over a billion CMOS sensors manufactured annually by 2013. Current production now reaches approximately seven billion CMOS sensors per year globally.
Diverse Applications
CMOS technology has been integrated into numerous daily devices and critical scientific missions, demonstrating its versatility and reliability:
- Consumer & Commercial:
- Digital still and video cameras (including cell phones)
- Automotive electronics
- Webcams and sports cameras
- Industrial equipment
- Security cameras (e.g., doorbells)
- Medical and dental imaging
- Space Science & Exploration:
- Engineering cameras for NASA's Perseverance Mars rover's entry, descent, and landing.
- OCO-3 mission, monitoring Earth's carbon dioxide distribution.
- Scientific imagers on NASA's Parker Solar Probe mission.
- Upcoming missions: Europa Clipper (to Jupiter's moon Europa) and UVEX (for galaxy and star evolution).
- Monitoring deployments of CubeSats and SmallSats, such as Pandora, BLACKCAT, and SPARCS.
- Development for future life-searching missions like the Habitable Worlds Observatory.
Industry Recognition
Dr. Eric Fossum was awarded the prestigious 2026 Charles Stark Draper Prize for Engineering by the National Academy of Engineering (NAE). This significant award recognizes his innovation, development, and commercialization of the CMOS active pixel image sensor, acknowledging its profound societal impact. The initial development efforts at JPL were funded by JPL and NASA.