The 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 drawbacks, including mass volume availability, required eye-safety measures and high cost. Now, Lumileds has demonstrated that its Luxeon IR domed and Luxeon IR compact LEDs can offer suitable alternatives to VCSEL technology for TOF applications operating up to 40MHz.
To demonstrate this, engineering teams from Lumileds and Melexis have developed an evaluation kit that allows designers to operate the Luxeon IR LEDs to frequencies up to 40MHz. The intrinsic properties of these LEDs 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 6 ns, which is a factor of 4 over other similar LED devices. 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,” explained Erno Fancsali, Director CPAT EMEA at Lumileds.
“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,” said Wouter Schrama, Sr. Product Manager for the Luxeon IR Family at Lumileds. “The joint evaluation kit with Melexis can help our customers reduce their development time significantly and enable them to successfully enter the market”.
Lumileds and Melexis have reported the results in a whitepaper.
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