VCSEL Illuminator with Micro-Lenses for Multi-Zone NIR Control
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Solution Overview
Problem
Current near infrared (NIR) illumination systems face challenges in controlling illumination intensity across different zones of an image sensor's field of view, leading to issues like saturation and limited detail visibility due to the modest dynamic range of electronic image sensors and the limitations of LED and laser diode sources.
Innovation Solution
The use of vertical-cavity surface-emitting laser (VCSEL) arrays with integrated micro-lenses for beam shaping, allowing for independently addressable and adjustable illumination zones, reducing coherence noise and enhancing eye-safe exposure levels by configuring multiple low-power incoherent emitters as an extended source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single laser source is used for illumination, then illumination power and efficiency are improved, but coherence noise and eye safety issues worsen
Solution Approach 1:
The patent divides a single high-power laser source into multiple lower-power laser beams using beam splitting optics. This segmentation maintains total illumination power while reducing coherence noise, as the divided beams have reduced mutual interference effects compared to a single high-power beam.
2Power
If a single laser source is used for illumination, then illumination power is improved, but eye safety worsens
Solution Approach 1:
The patent segments the single high-power laser source into multiple lower-power beams. This distribution of power across multiple beams reduces the power density of individual beams, thereby improving eye safety while maintaining total illumination power through the combined effect of all beams.
3Object-affected harmful factors
If LED illumination is used, then eye safety and freedom from coherence noise are improved, but illumination intensity and efficiency worsen
Solution Approach 1:
The patent combines multiple low-power laser beams into a unified illumination field that covers the same area as LED illumination would provide. By merging the effects of multiple coherent sources, the system achieves LED-like illumination uniformity and coverage while maintaining the higher efficiency and intensity advantages of laser sources.
4Object-generated harmful factors
If LED illumination is used, then freedom from coherence noise is improved, but illumination efficiency worsens
Solution Approach 1:
The patent uses multiple segmented laser beams instead of a single LED source. This segmentation approach maintains the coherence noise freedom of distributed sources while achieving superior illumination efficiency through the inherently higher wall-plug efficiency of laser diodes compared to LEDs, particularly at higher power levels.
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
This solution provides precise control over illumination levels across various zones, improving image processing performance by reducing saturation and enhancing features like object tracking and gesture recognition, while maintaining eye safety and efficiency.
Implementation Method 1
vertical-cavity surface-emitting laser (VCSEL) arrays with integrated micro-lenses for beam shaping
Implementation Method 2
integrated micro-lenses for beam shaping
Implementation Method 3
reducing coherence noise and enhancing eye-safe exposure levels by configuring multiple low-power incoherent emitters as an extended source
Data Source
AI summary
Methods, devices and systems are described for selectively illuminating different zones of a field of view by a multi-zone illumination device. In one aspect, a multi-zone illuminator may include a plurality of vertical cavity surface emitting lasers (VCSELs), and a plurality of micro-optical devices aligned with apertures of individual or groups of VCSELs, which are configured to be individually activated to provide adjustable illumination to different zones of a field of view of an image sensor. In another aspect, a method of selective illumination may include receiving information specifying a field of view of a camera, and controlling at least two sub arrays or individual illuminators of an illuminating array to output light at independently adjustable illumination powers, wherein each of the at least two sub arrays are independently configurable to illuminate at least one of a plurality of separate zones corresponding to the field of view of the camera.