Substrate requirements to enable durability and accuracy in structured-light based 3D sensing

Applications that require awareness of the structure, environment or objects are growing, and include augmented and virtual reality applications, gesture recognition and facial recognition for consumer, industrial and entertainment applications. This is creating a demand for 3D data capture and the use of depth sensors. Structured Light Illumination (SLI) is one of the leading depth sensor technologies. It is an indirect measurement of distance through observed distortion of a projected light pattern. To miniaturize these sensors for consumer applications, custom optics are required for the projector including diffractive optical elements (DOE). SLI is currently preferred due to its small form factor, high resolution and low power consumption. It can deliver high spatial resolution while working in low light conditions. To use SLI for high accuracy applications, the stability of the pattern under various environmental conditions and temperature ranges is required. We show simulations of the impact of the DOE substrate CTE on the generated dot patterns, and ultimately the depth accuracy and distortion of the 3D image. Measurements of commercially available consumer structured light sensors support the simulations.