Lumileds and Melexis demo LUXEON IR LEDs operating up to 40MHz, enabling 940nm and 850nm TOF applications up to 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. However, VCSEL technology has drawbacks including mass volume availability, required eye-safety measures and high cost. Now, LED maker Lumileds LLC of San Jose, CA, USA has demonstrated that LUXEON IR Domed and LUXEON IR Compact LEDs can be suitable alternatives to VCSEL technology for TOF applications operating at high frequencies up to 40MHz.

To demonstrate this, engineering teams from Lumileds and Melexis NV of Ypres, Belgium (which provides automotive semiconductor sensors) have developed an evaluation kit that allows the operation up to 40MHz of LUXEON IR LEDs, whose intrinsic properties result in a clean and repeatable response curve required for TOF operations.

“The illuminator evaluation kit developed by Lumileds reduces the rise and fall times of the light pulses to 6ns, which is a factor of four over other similar LED devices,” says Erno Fancsali, director CPAT (Customer Program Application Team) EMEA (Europe, Middle East and Africa) at Lumileds. “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,” he adds.

“This breakthrough in high-frequency operation of LUXEON IR LEDs enables new TOF applications previously limited by cost or eye-safety constraints,” says LUXEON IR Family senior product manager Wouter Schrama. “This development will help to bring affordable and eye-safe distance measurements to a much 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, by request. “The joint evaluation kit with Melexis can help our customers reduce their development time significantly and enable them to successfully enter the market,” Schrama adds.

“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; the performance of the system in terms of range and accuracy provides a compelling value proposition for the emerging TOF systems,” reckons Melexis’ product marketing manager Gualtiero Bagnuoli.

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

Tags: Lumileds

Visit: www.lumileds.com/uploads/788/WP35-pdf

Visit: www.melexis.com