VCSEL Array Eye Safety Control via Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mobile devices' near-infrared (NIR) structured light projectors can potentially harm users' eyes due to prolonged exposure, violating eye safety regulations, and existing systems struggle to minimize NIR light projection while maintaining sufficient light intensity.
Innovation Solution
A system that locates and tracks the user's eyes using cameras and controls the intensity of the VCSEL array in the NIR structured light projector, ensuring no light is projected onto the eyes by turning off or reducing the intensity of specific light sources imaged onto the eyes, while increasing intensity for other areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the intensity of VCSELs in the VCSEL array is increased to provide sufficient light for structured light projection, then the productivity and measurement precision are improved, but the object-affected harmful factors worsen due to potential eye damage from NIR light exposure
Solution Approach 1:
The VCSEL array is divided into multiple independently controllable light sources, allowing selective activation of specific VCSELs based on their projected positions relative to detected eye locations. This segmentation enables the system to activate sufficient light sources for adequate illumination while excluding those that would project onto eyes, thus resolving the contradiction between light intensity and eye safety
Solution Approach 2:
Different regions of the VCSEL array are assigned different operational states (active or inactive) based on local spatial relationships with detected eyes. The system applies local quality control by adjusting the intensity or activation status of individual VCSELs or groups of VCSELs in specific regions, allowing high intensity in safe regions while maintaining zero or low intensity in eye-projection regions
2Measurement precision
If the total power emission of the SL projector is increased to improve depth calculation precision and imaging quality, then the measurement precision is improved, but the object-affected harmful factors worsen due to higher NIR light exposure risk
Solution Approach 1:
The projector power is segmented across multiple VCSELs that can be independently controlled. By activating only the subset of VCSELs whose projected patterns fall outside eye regions, the system achieves sufficient total power for accurate depth calculation while minimizing harmful NIR exposure to eyes
Solution Approach 2:
The system continuously detects eye positions and uses this feedback to dynamically adjust which VCSELs are activated. This real-time feedback loop ensures that the projector maintains optimal power levels for measurement precision while adapting to prevent harmful exposure as eye positions change
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
Significantly reduces eye exposure to NIR light, allowing for higher total power emission while adhering to eye safety regulations, ensuring user safety and compliance.
Implementation Method 1
Each VCSEL creates a separate dot of NIR light. The spatial arrangement of the VCSELs in the array and the replicating DOE determines how the dots are imaged onto the scene.
Implementation Method 2
The spatial arrangement of the VCSELs in the array and the replicating DOE determines how the dots are imaged onto the scene.
Implementation Method 3
A NIR-sensitive camera images the face with the pattern projected on it.
Data Source
AI summary
Systems and methods for mitigating or preventing eye damage from structured light IR/NIR projector systems. When a SL projector with a multi-light-source array that projects a SL pattern onto an object, a first camera images the light pattern projected on the object and optionally provides camera frames viewed by a user. A multi-light-source array controller is configurable to control separately an on or off status and/or an intensity of each light source in the multi-light-source array, and an algorithm is operative to detect in the first camera frames SL pattern elements projected onto the object, to detect the eyes of the user, to compare a position of each projected SL pattern element with a position of the detected eyes, and to send commands to the multi-light-source array controller to turn off or reduce the intensity of array light sources that are projected or likely to be projected onto the user's eyes.