Laser Diode Matrix Illuminator Prism Light Pipe Collimation
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Solution Overview
Problem
Existing laser illuminators using high-brightness matrices of laser diodes face challenges in achieving homogeneous illumination with controlled divergence, compactness, and efficient collimation, due to the asymmetrical beam properties of semiconductor lasers, which complicates the manufacture and alignment of collimating devices and results in loss of brightness and increased cooling difficulties.
Innovation Solution
A long-range laser illuminator design featuring a matrix of high-brightness infrared emitters with a prism-shaped light pipe that processes and collimates beams into a single, homogeneous beam, where the light pipe has a flat input face opposite the emitters and a flat output face for collimation, allowing for geometric control of the final lighting angle and improved compactness and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of the emitter matrix is increased to achieve higher lighting power, then the total power increases, but the component loses compactness and rigidity, and source brightness is reduced
Solution Approach 1:
Multiple laser diode emitters arranged in a matrix are merged into a single integrated emitting surface, combining their individual beams into a unified output that maintains compactness while achieving high total power through coherent or incoherent summation of emitter outputs
Solution Approach 2:
The emitter matrix is arranged in a two-dimensional configuration rather than a single line, allowing power scaling in both horizontal and vertical dimensions while maintaining a compact footprint through optimized spatial distribution of emitters
2Power
If the density of emitters on the emitting surface is increased to achieve higher lighting power, then the source brightness increases and compactness is improved, but cooling becomes more complex and beam collimation becomes more difficult
Solution Approach 1:
A common heat sink or thermal management substrate serves as an intermediary structure that collects heat from multiple high-density emitters through integrated thermal pathways, simplifying cooling by providing a unified thermal interface rather than requiring individual cooling solutions for each emitter
Solution Approach 2:
The thermal conductivity and heat capacity parameters of the substrate material are optimized to efficiently conduct and dissipate heat from high-density emitters, allowing increased emitter density without proportionally increasing cooling complexity
3Power
If the density of emitters on the array is increased to achieve higher lighting power, then the source brightness increases and compactness is improved, but beam collimation becomes more difficult
Solution Approach 1:
Individual collimation optics are extracted from each emitter location and replaced with a single common collimation lens positioned at a distance from the emitter matrix, allowing all emitters to share one collimation element and simplifying the optical system while maintaining effective beam collimation
Solution Approach 2:
The emitter matrix is designed with pre-determined spacing and positioning that anticipates the requirements of a common collimation lens, allowing the lens to effectively collimate all beams simultaneously without requiring complex adaptive optics or individual adjustment mechanisms
4Manufacturing precision
If conventional collimation techniques with microlenses or microfibers are used for each emitter, then beam collimation is achieved, but the device complexity increases and manufacturing precision requirements increase
Solution Approach 1:
Individual microlens or microfiber collimation elements are merged into a single common collimation lens that serves all emitters in the matrix, reducing the total number of optical components and simplifying manufacturing while maintaining collimation quality through optimized lens design and positioning
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 the production of a compact, efficient laser illuminator with increased brilliance and controlled divergence, capable of producing a single, homogeneous beam that matches the geometry of night vision detectors, enhancing energy efficiency and simplifying manufacturing and alignment processes.
Implementation Method 1
a prism having a flat entrance face arranged opposite the emitter array and a flat exit face, the latter being arranged opposite collimation means
Implementation Method 2
the numerical aperture of said end of this optical fiber being greater than the numerical aperture of said sources
Data Source
Figure 1~3
Figure 4a~4b
AI summary
The illuminator has a matrix (3) of high brilliance laser emitters (4) that emit light beams, and a unit (6) disposed relative to the matrix for processing the light beams which are divergent along slow and rapid axes. The unit (6) includes a light guide (8) disposed relative and proximate to the matrix for combining the light beams and a homogenous light beam (7).