VCSEL Array Illuminator for Uniform Depth Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional direct time-of-flight (dTOF) systems for augmented reality headsets suffer from non-uniform illumination, which decreases the signal-to-noise ratio and requires scanning to capture complete depth information, increasing power consumption.
Innovation Solution
An illuminator with a plurality of light sources and a lens assembly where the focus of the lens assembly is positioned within an overlap plane, causing light from adjacent light sources to overlap, resulting in more uniform illumination of a region of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple beams of collimated light are emitted by separate light sources, then depth information can be obtained for different portions of the local area, but non-uniform illumination occurs and signal-to-noise ratio decreases
Solution Approach 1:
The patent merges multiple collimated beams of light from separate light sources into a single unified illumination pattern by focusing them through a lens assembly to an overlap plane, causing the beams to combine and uniformly illuminate the target area, thereby resolving the non-uniform illumination problem while maintaining depth sensing capability
Solution Approach 2:
The patent transforms the spatial arrangement of light sources from separate collimated beams in three-dimensional space to a focused overlap plane configuration, changing the dimensional organization of light propagation to achieve uniform illumination across the target area
2Measurement precision
If scanning is used to capture complete frame of depth information, then all areas can be illuminated, but power consumption increases
Solution Approach 1:
The patent enables continuous simultaneous illumination of the entire target area by focusing multiple light sources to an overlap plane, eliminating the need for sequential scanning operations, thereby maintaining complete depth information coverage while continuously reducing power consumption
Solution Approach 2:
The patent pre-arranges the optical paths of multiple light sources through the lens assembly to converge at the overlap plane before illumination, so that all areas are simultaneously covered from the start without requiring sequential scanning actions
3Productivity
If separate collimated beams are used for each light source, then each beam can illuminate specific portions, but signal-to-noise ratio decreases due to non-uniform illumination
Solution Approach 1:
The patent combines multiple separate collimated beams into a unified illumination field by focusing them to an overlap plane where the beams merge and overlap, creating uniform illumination that improves the signal-to-noise ratio of the reflected light captured by the detector
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides more uniform illumination, improving the signal-to-noise ratio and reducing power consumption by eliminating the need for scanning, while maintaining accurate depth sensing.
Implementation Method 1
a lens assembly configured to receive light emitted by one or more of the light sources and to direct the light into a local area, the lens assembly positioned relative to the array of light sources so a focus of the lens assembly is within an overlap plane where light from adjacent light sources of the array at least partially overlap
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A depth camera assembly includes an illuminator that dynamically illuminates different regions of a local area. The illuminator comprises an array of light sources, such as a vertical-cavity surface emitting laser (VCSEL) array, and a lens assembly. The array of light sources may include a plurality of groups of one or more light sources, with each group being independently addressable. The lens assembly is positioned so a focus of the lens assembly is in a plane where illumination from adjacent light sources of the array at least partially overlaps. Such positioning of the lens assembly focus causes light from adjacent light sources to blur into each other, forming flood illumination for a region of the local area. In some embodiments, the flood illumination may alternatively or additionally be achieved by introducing aberration into the lens assembly, including a microlens array in the illuminator or some combination thereof.