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SINGAPORE: Researchers from the Nanyang Technological University (NTU) have made a breakthrough in the field of light detection and ranging sensors (LiDAR), which could see the key component of autonomous vehicles becoming 200 times cheaper – and the size of a fingertip.

Driverless cars use LiDAR sensors to build a three-dimensional (3D) map of objects around the vehicle. The sensors send out light beams and detect those that are reflected back in order to measure where obstacles are.



That is how autonomous vehicles avoid collisions and keep other road users safe.

Currently, LiDAR sensors make use of laser diodes to generate laser beams. These sensors spin furiously to cover a 360-degree view of a car’s surroundings and create the 3D map.

Autonomous vehicles in Singapore can be identified by the LiDAR sensors spinning furiously atop their roofs.

But this makes LiDAR sensors expensive and ephemeral.



“Because of the mechanical moving parts, you have to actually replace the LiDAR before you have to replace your car tyres,” said Dr Nam Donguk, who is the lead researcher on the LiDAR sensors project.

But NTU’s researchers have found a way to emit light from a silicon chip instead, which will replace the need for the diodes.

They found a way to stretch germanium – commonly used as transistors in electronics, especially in central processing units (CPUs) – and found that the element is better able to emit light when stretched.

It is the first time scientists have been able to find a way to emit light from a material that is compatible with silicon.

In fact, it was previously thought to be close to impossible to create an on-chip laser for LiDAR – also known as a solid state LiDAR.

The chip-sized LiDAR sensors (left) and the current LiDAR sensors that are used on autonomous vehicles currently.

CHEAPER AND BETTER

Currently, the cheapest conventional LiDAR sensor costs S$10,000, while the solid state micro LiDAR chip will cost just S$50 when it is commercially-ready.

“Since we can make our LiDAR chip with our technology using mass production, which means anybody can buy it with maybe S$50, it will open up the opportunities for maybe smaller companies who want to make autonomous vehicle technology to be ready,” said Dr Nam.

“As of now, conventional LiDAR is too expensive, so not many companies can really jump in so easily.”

Another benefit is that image quality from the micro LiDAR silicon chip will be of a much higher resolution, thanks to the density of lasers on the chip, and images can be retrieved much faster than with conventional LiDAR sensors.

The breakthrough is also likely to make other technologies cheaper, faster and more reliable.

For example, the micro LiDAR chip can be mounted on drones, which is currently impossible given the heavy weight of conventional LiDAR sensors.

It could also be used in mobile phone chips.

“The other possibility that I can think of is basically to replace WiFi technology with light communication, we call it LiFi technology,” said Dr Tan Chuan Seng, Associate Chair (Research) in NTU’s School of Electrical and Electronic Engineering, who oversees the project. “Those are the exciting applications we can foresee."

The team behind the project has been awarded a grant by the National Research Foundation to get the technology ready for commercial use, which could be in the next five years.

