Many autonomous car efforts use lidar (light detecting and ranging) to “see” the world. Combining a laser transmitter and receiver, lidar detects the tiny but measurable time it takes for the laser to bounce off an object to determine how far away it is.
By steering the laser, the lidar can produce a 3D scan of its surroundings.
The earliest lidar scanning methods steered the laser either by moving the laser transmitter itself or by redirecting it with a spinning mirror. These are a familiar sight on prototype autonomous vehicles, partially due to their large size, roughly that of a coffee can. More recent ones like the Velodyne pucks are a little less obtrusive.
Phased array steering
A phased array lidar steers its beam without moving parts. Several transmitters are arranged in an array. The beams from these transmitters interfere with each other, making a stronger signal in some directions and weaker in others. By adjusting when each transmitter begins and ends its electromagnetic wave, the strong signal can be “steered”.
This is an improvement over mechanical steering, as it scans faster and can be made smaller. The downside of this is that it requires multiple transmitters, making it costly both in terms of manufacturing and power requirements.
Quanergy is a leading supplier of this type of lidar, which it describes in this video.
Optical metasurface steering
A optical metasurface is like a solid state lens on a chip. It redirects a single laser beam to perform a scan. This technology is faster, more energy efficient and promises to be cheaper once built at scale.
Researchers at Purdue University and Stanford University describe this as a breakthrough.
“The researchers say their innovation is orders of magnitude faster than conventional leading-edge laser beam steering devices that use phased antenna-array technology.”
Moving from mechanical steering to phased array steering is informed by Principle 1 – Segmentation, breaking up a single sensor into an array of multiple sensors. It also follows Laws of Technical System Evolution by transitioning from a mechanical system to an electromagnetic system.
This same evolution can be derived from SCAMPER Adapt, as lidar is an adaptation of radar technology which also transitioned from mechanical steering to phased arrays.