Light Engine Combining High and Low Etendue Beams
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Solution Overview
Problem
There is a demand for multi-spectral light engines that can combine light from different types of sources with varying emission characteristics, such as LEDs, optical fiber-based sources, and laser diodes, to meet the requirements of advanced multi-spectral devices like laparoscopes and endoscopes, which need greater flexibility in fluorescence imaging.
Innovation Solution
A light engine system that combines a high-etendue light source with a low-etendue light source using a light guide with a distal end face to emit a second light beam within the expanded optical path of the first light beam, without passing through an aperture in a light redirecting element, and an optical condenser to direct both light beams to a common exit plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If light from multiple different light sources with varying etendue is combined, then spectral flexibility and imaging capabilities are improved, but device complexity and alignment difficulty increase
Solution Approach 1:
The patent combines multiple light sources with different etendue values (high-etendue LED source and low-etendue laser source) into a single integrated light engine system. The light guide integrates both light sources and their optical paths, merging them into a unified structure that delivers combined light output through a single interface, thereby achieving spectral flexibility without proportionally increasing device complexity.
Solution Approach 2:
The light guide acts as an intermediary component that receives light from both high-etendue and low-etendue sources, guides them through separate but integrated optical paths, and combines them at the output. This intermediary structure simplifies the overall system architecture by providing a common platform for integrating diverse light sources with different optical characteristics.
2Adaptability or versatility
If a light guide is used to deliver low etendue light within the expanded optical path, then light source integration is improved, but precision in positioning and alignment is required
Solution Approach 1:
The patent utilizes the spatial dimension by having the light guide enter the expanded optical path from the periphery rather than from the central axis. This off-axis entry point allows the low-etendue light to be injected into the expanded beam path without requiring precise axial alignment, thereby reducing manufacturing precision requirements while maintaining effective light source integration.
Solution Approach 2:
The light guide creates a virtual copy or replica of the light source output by delivering the low-etendue light through its distal end face within the expanded optical path. This copying approach allows the low-etendue light to follow the same optical path as the high-etendue light without requiring direct physical alignment between the two sources, simplifying the positioning requirements.
3Ease of operation
If the distal end face of the light guide enters through the periphery of the expanded optical path, then alignment complexity is reduced, but the structural design becomes more challenging
Solution Approach 1:
The patent segments the optical path into distinct regions: the expanded optical path from the high-etendue source and the separate light guide path from the periphery. This segmentation allows each component to be designed and aligned independently, with the light guide entering through the periphery of the expanded path, thereby simplifying alignment procedures while the integrated housing provides the necessary structural complexity management.
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 enables the generation of a combined light beam with specific spectral characteristics, enhancing the capabilities of multi-spectral devices by providing greater flexibility in fluorescence imaging and improving the efficiency and compactness of the light engine system.
Implementation Method 1
a collector optical system arranged to receive the diverging first light beam and form therefrom an expanded first light beam that travels over a first expanded optical path
Implementation Method 2
a light guide having a proximal end section in optical communication with the first light source and having a distal end section that enters the first expanded optical path through the periphery, the distal end section having an end face, the light guide configured to conduct the second light from the second light source and emit the second light from the end face as a second light beam
Implementation Method 3
an optical condenser configured to receive and direct the first light beam and the second light beam to a common exit plane to form the combined light beam
Data Source
AI summary
A first light source with a first etendue generates a first light beam to travel along a first optical path having an expanded portion formed by a collector optical system. A second light source having a second etendue less than one tenth of the first etendue forms second light, which is conducted by a light guide having a distal section with an end face. The second light is emitted from the end face as a second light beam that travels over a second optical path that resides within the expanded portion of the first optical path due to the light guide being disposed relative to the first optical path from an off-axis direction. An optical condenser receives and directs the first and second light beams to a common exit plane to form the combined light beam.