Sony Unveils First Single‑Chip SPAD Lidar Sensor for Automotive Applications

As automotive cameras and millimeter‑wave radar grow, lidar is cementing its role in high‑precision road‑condition sensing and object detection. Yet challenges remain: improving distance‑measurement accuracy, ensuring safety and reliability across diverse environments, and moving toward solid‑state, compact, and cost‑effective designs. Sony is tackling these hurdles with a breakthrough in lidar technology.

Single‑photon avalanche diode (SPAD) pixels form the core of direct time‑of‑flight (dToF) sensors, measuring distance by timing the return of light emitted by a source after it reflects off an object.

Sony’s new IMX459 SPAD depth sensor merges SPAD pixels and a dedicated distance‑measuring processing circuit onto a single silicon die—an industry first for automotive lidar. Production is slated to begin in March 2022, promising enhanced detection and recognition performance for advanced driver‑assist systems (ADAS) and autonomous driving (AD).

The IMX459 builds on Sony’s mature CMOS image‑sensor heritage, incorporating back‑illuminated pixels, stacked die architecture, and copper‑copper (Cu‑Cu) interconnects. These features enable a 10 µm square pixel, yielding a compact 1/2.9‑inch format with roughly 100 000 effective pixels. The result is a high‑resolution, high‑speed sensor that delivers 15 cm distance resolution from short to long ranges while meeting automotive functional‑safety standards for reliability and safety.

In its stacked configuration, a Cu‑Cu bond connects the top SPAD pixel chip to a bottom logic die that houses the distance‑processing circuitry. This layout preserves a high aperture ratio and keeps the pixel pitch to 10 µm. The sensor’s light‑incidence plane features micro‑irregularities that refract incoming photons, boosting absorption efficiency.

With a 24% photon‑detection efficiency at the 905 nm wavelength commonly used in automotive lidar, the IMX459 can reliably detect low‑reflectivity targets at high resolution. An active recharge circuit—also linked via Cu‑Cu to each pixel—delivers a response speed of approximately 6 ns per photon under normal operation.

The sensor is qualified to AEC‑Q100 Grade 2 automotive electronic reliability tests and has been engineered to satisfy ISO 26262 functional‑safety requirements, supporting ASIL‑B(D) for failure detection, notification, and control. These certifications underpin the lidar’s safety and dependability for future mobility solutions.

Sony has released a mechanical‑scanning lidar reference design that integrates the IMX459, enabling customers and partners to accelerate development, reduce engineering effort, and lower overall costs.

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