IR light source developed combining features of VCSELs and LEDs

ROHM has established VCSELED, a new infrared light source technology that encapsulates a VCSEL element in a resin optical diffusion material for laser light. It is currently developing this technology for commercialisation as a light source for improving vehicle Driver Monitoring Systems (DMS) and In-Cabin Monitoring Systems (IMS).

To improve automotive safety further, driver monitoring systems are increasingly being installed in vehicles equipped with ADAS to detect drowsiness, sleepiness, and distracted driving. In Japan, the Ministry of Land, Infrastructure, Transport, and Tourism has created guidelines that define the system's design and functions. In the EU, there are plans to make installation mandatory for all new vehicles sold in Europe from July 2024 onwards. Automakers and suppliers are also developing in-vehicle monitoring systems to detect occupants other than the driver, and there is a growing awareness of the necessity for high-performance light sources that allow detection systems to function with greater precision.

In response, the company has developed VCSELED, which attains high-accuracy sensing. Minimal wavelength temperature variation and a wide emission beam angle make it excellent for in-vehicle monitoring systems. It also contributes to improving the accuracy and performance of inspection systems for robots and industrial equipment, as well as spatial recognition and ranging systems.

VCSELED extends the beam (irradiation) angle similar to LEDs by combining a high-performance VCSEL element and light diffusion material to facilitate sensing over a wider area with higher accuracy than VCSELs. What is more, the light-emitting element and light diffuser are incorporated into a compact package, contributing to smaller, thinner applications.

The VCSEL element used in VCSELED features a narrow emission wavelength bandwidth of 4nm, approximately one-seventh that of LEDs. This characteristic improves resolution performance on the receiving side while eradicating the red glow often associated with LEDs. At the same time, a wavelength temperature variation of 0.072nm/C – less than one-fourth that of LEDs (0.3nm/C) – allows for high-accuracy sensing unaffected by temperature changes. Furthermore, the response time when emitting light is 2ns, approximately 7.5 times faster than LEDs, contributing to higher performance in ToF applications that use infrared light to measure distance.

The company is working on commercialising VCSELED as a new technology brand for infrared light source components. Prototype samples are available for purchase now, with mass production samples for consumers scheduled for release in October 2024 and automotive use in 2025, respectively.