Wide-Angle Illuminator Module Using VCSEL Arrays and Microlenses
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Solution Overview
Problem
Current near-infrared (NIR) illumination systems face challenges in providing a wide-angle field of illumination due to the broad emission profile of LEDs and the limited optical conversion efficiency and speckle noise of conventional laser diodes, which affect the dynamic range and accuracy of electronic image sensors.
Innovation Solution
A wide-angle illuminator module comprising a rigid support structure with angled faces, integrated VCSEL arrays, and a driver circuit to control multiple illumination zones, utilizing microlenses to direct and shape the light output, reducing coherence noise and increasing eye-safe exposure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional laser diodes are used for illumination, then narrow spectral emission and higher efficiency are achieved, but speckle noise and low eye-safe exposure levels occur
Solution Approach 1:
The patent divides a single high-power laser source into multiple lower-power VCSEL elements arranged in an array. Each VCSEL element emits light with lower coherence, reducing speckle noise while maintaining overall illumination efficiency. The segmented approach allows independent control of each element to optimize both efficiency and reduce coherence artifacts.
Solution Approach 2:
The patent applies different optical properties to different parts of the illumination system by using microlenses with varying focal lengths and offsets tailored to specific VCSEL elements. This local optimization allows each element to contribute efficiently to the overall illumination while minimizing speckle effects through varied beam characteristics.
2Power
If a single high-power laser source is used, then sufficient illumination power is achieved, but significant speckle noise and low eye-safe exposure levels result
Solution Approach 1:
The high-power illumination requirement is met by combining multiple VCSEL elements in an array configuration. Each element operates at lower power levels that are eye-safe, while the collective output of all elements provides sufficient total illumination power. This segmentation approach maintains eye safety while achieving the required illumination intensity.
Solution Approach 2:
The patent merges the output of multiple VCSEL elements to achieve the required total illumination power. By combining multiple low-power, eye-safe sources, the system attains high overall power output without the speckle noise and eye safety issues associated with single high-power laser sources.
3Object-generated harmful factors
If LEDs are used for illumination, then low cost and freedom from speckle noise are achieved, but broad emission profile and limited optical conversion efficiency occur
Solution Approach 1:
The patent introduces microlenses as intermediary optical elements between the VCSEL sources and the target. These microlenses focus and direct the light from each VCSEL element, improving optical conversion efficiency by directing more light toward the intended field of view. This intermediary optical system enables VCSELs to achieve LED-like efficiency while maintaining their inherent advantages of narrow spectral emission and absence of speckle noise.
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 enables adjustable and wide-angle illumination, enhancing image sensor capabilities for applications like object tracking and gesture recognition by reducing speckle noise and increasing the dynamic range of image sensors.
Implementation Method 1
a flexible circuit including one or more VCSEL arrays, each VCSEL array positioned over a face among the plurality of angled faces, each VCSEL array including a plurality of integrated microlenses with one microlens positioned over each VCSEL in the VCSEL array
Implementation Method 2
each VCSEL array including a plurality of integrated microlenses with one microlens positioned over each VCSEL in the VCSEL array
Implementation Method 3
A wide-angle illuminator module comprises a rigid support structure having a plurality of angled faces
Data Source
AI summary
A wide-angle illuminator module including a rigid support structure having a plurality of angled faces, a flexible circuit including one or more VCSEL arrays, each VCSEL array positioned over a face among the plurality of angled faces, each VCSEL array including a plurality of integrated microlenses with one microlens positioned over each VCSEL in the VCSEL array, and a driver circuit for providing electrical pulses to each VCSEL array, wherein the plurality of VCSEL arrays address illumination zones in a combined field of illumination. The support structure may also be a heatsink. The flexible circuit may be a single flexible circuit configured to be placed over the support structure or a plurality of flexible circuits, each including one VCSEL array.