Sheba Microsystems Solves the Automotive Autofocus Camera Problem

Some of us are old enough to remember the revelation seeing the improved image quality when we went from fixed-focus “instamatic” cameras to autofocus 35mm cameras, so it is easy to understand the value of crisp focus for image quality.

For automotive safety systems to work their best, they need a clear picture of the scene ahead, and Sheba Microsystems proposes replacing today’s instamatic-quality fixed-focus cameras with ones that can focus accurately over a wide range of temperatures.

Image quality will be more important as cameras become even more pervasive. Allied Market Research estimates that the market for automotive smart cameras will grow from $3.4 billion in 2023 to $27.2 billion by 2032.

It is fluctuating temperatures that wreak havoc with focus clarity, as the camera parts expand and contract at different rates. Sheba Microsystems’s new Sharp-7 automotive camera corrects for these changes using electrostatic micro-actuators to keep its 8-megapixel automotive-grade image sensor supplied with a clear image across the automotive temperature range of -40 to 150 degrees Celsius.

This issue is compounded by the increasing use of higher-resolution image sensors, which are the equivalent of using high-quality 35 mm film with the old fixed-focus camera lens. The smaller pixels in sensors with more pixels packed into them require more precise alignment of the optics to ensure that light is accurately focused on each pixel, according to Sheba. Any misalignment due to thermal expansion or contraction can lead to blurring or distortion.

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“The absence of reliable autofocus actuator technology that can operate in the automotive environment, coupled with the problem of thermal expansion, has been a decades-long blocker and has limited the adoption of high-resolution sensors in automotive cameras,” stated Sheba CEO and co-founder Faez Ba-Tis, PhD.

Sheba’s solution is to use micro-electromechanical systems (MEMS) technology to adjust the camera’s focus. We’ve seen MEMS used in actuators, tire pressure monitors, speakers, pressure sensors, lidar, and automotive timing systems, so it is no surprise to find another application for the technology.

The improved focus for advanced driver-assistance system (ADAS) cameras supports capabilities such as ultra-precise object detection, digital zooming, and more. Sheba’s unexpected solution for compensating for thermal expansion is to move the lightweight sensor along the optical axis instead of moving the heavier lenses.

The image sensor weighs only 2-3 percent of the optical lens’s weight, making it easier to move quickly and accurately for precise autofocus performance even when temperatures fluctuate. Sheba tests the mechanism for drop, thermal shock, thermal cycling, vibration, mechanical shock, tumble, and micro-drop to ensure durability.

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“With the Sharp-7 camera we wanted to demonstrate not only how Sheba MEMS technology solves for thermal expansion and produces consistent high-quality imaging from existing 8 MP sensors, but also how our technology paves the road towards the adoption of even higher resolution image sensors, which will ultimately keep everyone on the road safer, especially with today’s advancements in autonomous vehicle technology,” said Ba-Tis. “Our mobile phones should not have better cameras than our cars.”