In the past decade, the smartphone changed from being a luxury business tool to an integral part of everyday life. With that came the ability to take high-resolution photos on the go, and recent years have seen the ability to shoot HD-quality video too. However, one issue that has constantly plagued even top-of-the-line smartphones is the quality of low-light photos. Light sensitivity is based on standard CMOS image sensor technology, and even standalone digital cameras suffer from this issue.
InVisage, a Bay Area-based semiconductor company, has addressed this limitation with a groundbreaking innovation known as QuantumFilm. Utilizing a patented nanomaterial, QuantumFilm™ enhances the ability of devices to take quality photos despite a low-light environment.
Why does QuantumFilm succeed where traditional CMOS image sensors struggle? CMOS sensors use silicon for a dual function: both electronic read-out and light sensing, creating limits on light-absorption capabilities. QuantumFilm replaces the light sensing role of the silicon photodiode, with maximal light sensitivity across the spectral range.
QuantumFilm achieves this as a new class of semiconductor material designed specifically for the purpose of maximum light absorption. With QuantumFilm™, the entire area of the imaging array is now covered in a material dedicated to light sensing. Thanks to minimal diffusion of electrons and holes, electrical crosstalk is also minimized. This is brought into the real world through a custom manufacturing process that deposits the film on top of a silicon wafer with analog and digital circuitry. InVisage's proprietary technology enables a smooth and efficient manufacturing process, one that opens up QuantumFilm to the commercial market.
The difference is ultimately all in the numbers. Standard CMOS sensors are limited to a minimum of 1.1um pixel size. QuantumFilm leaps past this standard and brings manufacturing capabilities to a new level with industry-leading 1.1um pixels using a low-cost 110nm silicon process and even smaller pixels with smaller technology nodes.
Under these new specifications, many doors are opened for the consumer electronics market. After all, photography in all its forms is driven by a device's capability to capture light. QuantumFilm™ breaks new ground by enabling:
- Built-in global shutter capability
- Higher levels of light sensitivity
- Wider dynamic range across all wavelengths
- Higher image resolutions
- Extended spectral sensitivity previously unavailable due to silicon limitations
Smartphones evolve from year to year, with new iterations boasting advanced features and faster speeds. Camera technology is a key driver in this – in fact, a recent study demonstrated that more than half of those surveyed took photos exclusively on their smartphone. That means that people are turning to convenience despite the limitations of their technology. With QuantumFilm™, one of the biggest drawbacks facing image capture in smartphones and lower-tier digital cameras – the ability to work in low-light environments – is quickly becoming a non-issue. This leap forward can potentially transform the image sensor market, from budget cameras and smartphones to security cameras and laptop web cams, and regardless of how, when, or why cameras are used, the ultimate winner in all of this is the consumer.
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About the Author
Ted Sargent holds the rank of professor and Canada research chair in nanotechnology at the University of Toronto. In 2004–6 he was also visiting professor of nanotechnology at the Massachusetts Institute of Technology. In 2003 Mr. Sargent was named "one of the world's top young innovators" by MIT's Technology Review. He was awarded a Canada Research Chair at the University of Toronto in 2000. He received the B.Sc.Eng. (Engineering Physics) from Queen's University in 1995 and the Ph.D. in electrical and computer engineering (Photonics) from the University of Toronto in 1998.