Low-cost LED-based TOF System Measures Distance Upto 3m


Lumileds and Luxeon demo cost-effective IR LED alternatives to VCSEL technology for the emerging TOF distance measurement applications such as driver monitoring systems, logistics navigation, gesture recognition, and drones

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.

Lumileds and Melexis claimed that LUXEON IR Domed and LUXEON IR Compact LEDs can be ideal alternatives to VCSEL technology for TOF applications operating up to 40 MHz. The companies have demonstrated the operation of Luxeon IR LEDs at up to 40MHz, enabling TOF applications in 940nm and 850nm with a range of up to 3 meters.


According to the companies, the LED-based TOF system claims accuracy and range comparable to VCSEL-based solutions, while reducing the overall system cost.

TOF applications enabled with Lumileds Luxeon IR LEDs operating at up to 40 MHz

To demonstrate this, engineering teams from Lumileds and Melexis have developed an evaluation kit that allows customers to operate the LUXEON IR LEDs to high frequencies up to 40MHz. According to Lumileds, the intrinsic properties of the LUXEON IR 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,” said Erno Fancsali, Director CPAT EMEA at Lumileds.

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“This break-through in high-frequency operation of LUXEON IR LEDs enables new TOF applications previously limited by cost or eye-safety constraints. 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”.

“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,” said Gualtiero Bagnuoli, Product Marketing Manager at Melexis.

To learn more about the LUXEON IR LEDs and the evaluation kit, click here.



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