In no time at all, LiDAR sensors have established themselves as a key technology for automated processes, especially when it comes to fully-automated autonomous driving. For high-precision detection of distances between vehicles and their static and dynamic environment, the laser beam must be shaped into a light field with a defined field of view.
In fact, the most critical components - to engineer a state-of-the-art LiDAR system - are the optics that shape the laser light in the right direction. What’s more: Safe and reliable operation of the LiDAR system is only possible if the risk of injury from laser photons has been eliminated - something that requires a beam propagation without any hot spots. This in turn necessitates a consistent intensity distribution of the laser radiation, even at high ambient temperatures.
Thanks to its zero hot spot beam shaping, the wide-angle diffuser from LIMO delivers consistent performance, even in extreme operating temperatures (-40℃ - 150℃), while its expansive illumination area enables full coverage of the 360° surrounding view with just four LiDAR systems for reliable driving safety.
In contrast to the diffractive optical components (DOEs), which are limited to small angles and moderate ambient conditions and have an intensity distribution that drops flat towards at the edges, the LIMO diffuser technology takes a different approach: LIMOs glass refractive optical elements can disperse laser light in one direction up to a full illumination angle ranging from a few mrad to over 100°. When combined with a second functional surface, the light can also be shaped at any desired angle in the other direction, making it possible to obtain a rectangular field with a steep edge slope and a user-defined size of 125° x 25°, for example. These different angles illuminate the target area precisely and uniformly, while a surface structure defined for the customer’s application delivers a consistent intensity distribution for the specific application. This is beneficial for noise reduction and increases the signal-to-noise ratio, and it also enhances the range of the LiDAR sensors as a result.
These LIMO diffusers can be combined with all types of low- and high-power laser sources, even in the range of 1.4 < M² < 15, i.e., the range in which laser beam homogenization is a difficult task.
Wafer technology for large quantities
Just like other micro-optics made by LIMO, the diffusers can be manufactured on wafers using a revolutionary new, highly-productive processing method. LIMO fabricates high-quality glass laser optics on wafers measuring up to 300 mm x 300 mm, making it possible to offer consistently lower production costs for high-volume orders without sacrificing any quality. In light of the fact that LiDAR systems and 3D sensors are components that play a major role in the safety of autonomous driving, and because the quantities needed for this application are so large, the quality and cost structure of the optics are significant factors in the breakthrough of this technology.