What’s the secret to increasingly smaller sensors?

Actually, it’s no secret, but microelectromechanical systems (MEMS) and integrated circuit technology provide breakthroughs in size and the ability to further decrease size with next-generation designs. The breakthroughs can occur both in the research & development area and in volume production.

In the R&D area, CEA-Leti has prototyped a next-generation optical chemical sensor using mid-infrared (IR) silicon photonics for use in highly integrated smartphones and other portable devices. The IoT-ready sensors are coin-size and operate in the spectral range of 2.5 µm to 12 µm. The goal of the project was to achieve competitive performance using the tools and processes typical of the IC and MEMS industries for the design.

Three existing technologies were combined to produce on-chip optical chemical sensors:

• Integrating a mid-IR laser on silicon
• Developing photonic integrated circuits (PICs) in the mid-IR wavelength range, and
• Miniaturizing a photoacoustic detector on silicon chips.

For volume production, OmniVision Technologies, Inc., developed the OV2778 automotive image sensor, a 2-megapixel (MP) red, green and blue (RGB)-IR sensor for cabin and occupant monitoring. Built on OmniVision’s 2.8-micron OmniBSI-2 Deep Well pixel technology, the image sensor delivers a 16-bit linear output from a single exposure with best-in-class low-light sensitivity.

Since the OV2778 is offered in a 6.5 x 5.7-mm automotive chip scale package (CSP), it is the smallest package available for the automotive in-cabin applications. This enables the smallest camera sizes possible for easier and unobtrusive placement inside the passenger compartment. Targeting automotive applications, the image sensor is AEC-Q100 Grade 2 certified.