Lumileds, Melexis make advance in high-frequency infrared LEDs

20 Nov 2018

Partners demonstrate operation up to 40MHz Luxeon IR LEDs enabling time-of-flight applications in 940nm, 850nm with range of 3m.

High frequency operation of infrared light sources is rapidly gaining interest for various time-of-flight (TOF) applications in automotive, industrial and consumer segments. Due to the fast switching requirements of these applications, mostly vertical cavity surface emitting lasers (VCSELs) are being considered.

VCSEL technology, however, also comes with its disadvantages, including mass volume availability, eye-safety measures and high cost. Lumileds has shown that its Luxeon IR Domed and IR Compact LEDs are alternatives to VCSEL technology for TOF applications operating up to 40 MHz.

To demonstrate this, teams from Lumileds and Melexis have developed an evaluation kit that allows users to operate these IR LEDs to high frequencies up to 40MHz.

Erno Fancsali, Director CPAT EMEA at Lumileds, commented, “The illuminator evaluation kit reduces the rise and fall times of the light pulses to 6ns, which is a factor of 4 over other similar LED devices.

'Combination effect'

He continued, "This is enabled by optimizing the combination of improved peak current response of the Luxeon IR LEDS, the PCB design and boost electronics. The illuminator card enables an LED-based TOF system with accuracy and range comparable to VCSEL-based solutions, while reducing the overall system cost.”

Wouter Schrama, Senior Product Manager for Luxeon IR at Lumileds, said, “This development will help to bring affordable and eye-safe distance measurements to a broader range of products such as driver monitoring systems, logistics navigation, gesture recognition systems and drones.”

The Lumileds LED illuminator is available in 60°, 90°, and 150° fields of view and for 850nm and 940nm wavelengths. The joint evaluation kit with Melexis can help users reduce their development time significantly.

“The Lumileds solution pairs well with our new Automotive QVGA TOF chipset and will help accelerate the adoption of TOF systems, at an affordable cost point,” said Gualtiero Bagnuoli, Product Marketing Manager at Melexis.

Lumileds and Melexis have reported the results in a whitepaper that can be downloaded from the Lumileds website.