In addition to LiDAR and DMS in ADAS, TriLumina is targeting depth sensing and gesture control for the industrial robotics, commercial and consumer electronics markets.

It’s critical to work with leading Tier 1 suppliers like DENSO as we introduce and deploy technology that will shape the automotive industry for years to come. It’s a tremendous endorsement of our technology to have DENSO engage as one of our Tier 1 partners, work with us to become qualified, and help fuel development.

—Kirk Otis, chief executive officer of TriLumina

TriLumina has developed unique architecture for two-dimensional arrays of Vertical Cavity Surface Emitting Lasers (VCSELs) that allow for simultaneous high-power output and high-bandwidth modulation. The arrays use integrated micro-lenses for beam shaping and control, and to enable incoherent beam combining to make compact, high-brightness sources with low coherence noise.

In our approach to VCSEL array technology we use flip-chip bonding that employs a sub-mount. Here, the VCSEL die is constructed in gallium arsenide, then flip-chip bonded to a ceramic or silicon sub-mount that has patterned metal on its surface. Each of the individual VCSEL elements that make up the array is formed by a mesa structure … The anodes of the individual VCSEL elements are connected to the common sub-mount anode pad via solder bumps that are reflowed to the anode metallization of the sub-mount. The VCSEL elements are designed to emit light through the back of the substrate at wavelengths in the 905 to 980 nm range.

A useful feature of this approach is that micro-lenses can be etched in the emission side of the substrate. These can be used to collimate and/or manipulate the combined array of light beams. The cathode side of the array is connected to the common cathode of the sub-mount by a set of common shorted solder bumps. The metal patterns of the sub-mount are arranged to form an impedance-matched electrical waveguide structure … This enables the array to be modulated at higher speeds than could be obtained if the VCSEL elements were added as discrete, individual parts … The ability to integrate micro-lenses into the emission side of the laser die provides a powerful capability for beam shaping and manipulation.

—Warren et al.

Cross-section of TriLumina’s VCSEL array structure. Warren et al. Click to enlarge.

TriLumina’s VCSEL configuration, with light passing through the substrate in a back-emitting design that is coupled with high-speed circuits, results in a smaller, less-expensive laser source well-suited to requirements of flash lidar applications, explained John Joseph, TriLumina founder, in a 2015 article in Laser Focus World.

Flash LiDAR uses high-speed pulsed laser flashes, and triggers a time that counts the time it takes for each pixel of a focal plane array or timed camera to respond to the infrared light pulse.

TriLumina currently offers two main products:

• LiDAR-IR Laser Array Fields for LiDAR and advanced driver assistance systems. TriLumina provides a scalable high-power modulated illumination source for LiDAR and long distance time-of-flight applications. With pulsed power operation capabilities into the kilowatts and consumer level pricing, TriLumina enables high accuracy LiDAR for the automotive market.

• NUI-IR Laser Array Chip for Smart Illumination and Depth Sensing. The TriLumina family of High Speed VCSEL Array Emitters (HSVAE) provides a fast scalable-power near-IR emitter solution for a wide range of applications.

DENSO’s Silicon Valley office actively works with startup companies, and through these types of partnerships expects to gain access to new technologies in the areas of autonomous drive, electric vehicles, transportation, batteries, and energy storage while also expanding DENSO’s overall presence and visibility within entrepreneurial networks.

Resources

• Mial E. Warren; Richard F. Carson; John R. Joseph; Thomas Wilcox; Preethi Dacha, et al. (2015) “High-speed and scalable high-power VCSEL arrays and their applications” Proc. SPIE 9381, Vertical-Cavity Surface-Emitting Lasers XIX doi: 10.1117/12.2080235