Full Spectrum LED Illuminator for Endoscopy
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Solution Overview
Problem
Illumination systems for endoscopy and microscopy face challenges in achieving bright, full visible spectrum illumination using solid state light sources due to limitations in output brightness and spectral coverage, particularly with LEDs, which struggle to match the performance of arc lamps and require complex optical designs to overcome etendue constraints and cooling issues.
Innovation Solution
A solid state illuminator utilizing multiple high power LEDs spanning the visible spectrum, carefully selected and powered to produce a color-balanced output, combined using mirrors or dichroic filters, and coupled into optical light guides via high NA lenses, with advanced thermal management and optical path optimization to enhance efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple different colored LEDs are combined using dichroic mirrors to source emitting over a wide spectral range, then spectral coverage is improved, but device complexity and etendue constraints worsen
Solution Approach 1:
The illumination system divides the visible spectrum into multiple wavelength regions, with each region served by a dedicated LED source (violet, blue, cyan, green, yellow-green, yellow, orange, red). This segmentation allows each LED to be optimized for its specific wavelength range while collectively covering the entire visible spectrum, resolving the contradiction between spectral coverage and device complexity.
Solution Approach 2:
The patent transitions from a single LED source to a multi-dimensional array of wavelength-specific LED sources arranged in a linear configuration. This dimensional expansion from one to multiple wavelength dimensions enables broad spectral coverage while maintaining manageable complexity through systematic arrangement and shared optical components.
2Illumination intensity
If higher power LED light sources are used to increase total light output, then brightness is improved, but thermal management challenges worsen
Solution Approach 1:
The patent introduces a dedicated cooling system as an intermediary component between the LED sources and the surrounding environment. This cooling system acts as a thermal mediator, actively removing heat from the high-power LED sources to prevent thermal accumulation, thereby enabling high light output without excessive temperature rise.
Solution Approach 2:
The patent replaces passive thermal management with an active cooling system that uses refrigeration cycles or thermoelectric devices to actively pump heat away from the LEDs. This substitution of mechanical/passive thermal management with active controlled cooling enables higher power operation while maintaining acceptable temperature levels.
3Illumination intensity
If arc lamp or halogen technology is used to achieve bright illumination, then brightness is improved, but spectral quality and efficiency worsen
Solution Approach 1:
The patent changes the fundamental operating parameters of the light source by transitioning from thermal radiation (arc lamp/halogen) to electroluminescence (LEDs). This parameter change enables broader spectral coverage with higher efficiency, as each LED emits light through electrical excitation rather than thermal processes, eliminating the efficiency losses inherent in thermal radiation.
Solution Approach 2:
The patent employs a composite approach by combining multiple LED sources with different emission characteristics to create a composite light output that matches or exceeds the performance of traditional arc lamps. This composite material approach in optics combines the advantages of different LED types to achieve broad spectrum coverage while maintaining solid-state efficiency.
4Adaptability or versatility
If green LED output is increased to match arc lamp levels, then spectral balance is improved, but manufacturing precision and reliability worsen
Solution Approach 1:
The patent merges multiple green LED sources with different emission characteristics to achieve a composite green output that is both intense and spectrally balanced. By combining the outputs of multiple green LEDs, the system achieves the desired spectral balance while the redundancy of multiple sources improves overall reliability compared to relying on a single green LED configuration.
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 provides a cost-effective, reliable, and bright, color-balanced, broad-spectrum visible light output that can be effectively coupled into optical light guides, with optional UV or NIR illumination for fluorescence excitation, overcoming previous limitations in brightness and spectral coverage.
Implementation Method 1
multiple high power LED light sources that span the visible spectrum (e.g. from 400 - 700 nm)
Implementation Method 2
solid state light sources to produce a bright, color balanced, broad spectrum visible light output
Implementation Method 3
The light produced by these LEDs is combined into a single beam using either mirrors or dichroic filters appropriately wavelength matched to the LED light output
Implementation Method 4
dichroic filters appropriately wavelength matched to the LED light output
Implementation Method 5
The combined light may then be coupled into an optical light guide using an appropriate optical element such as a high (e.g. > 0.5) NA lens
Implementation Method 6
coupled into optical light guides via high NA lenses
Implementation Method 7
advanced thermal management and optical path optimization to enhance efficiency and reliability
Data Source
Figure 1~2
Figure 3~4
AI summary
An apparatus for providing a light output to an optical guide for illumination of an imaged object including a plurality of solid state light-emitting sources each of which are independently powered and independently controlled, each light-emitting source emitting light at a wavelength which is different from the wavelength emitted by the other light-emitting sources. The apparatus also includes a heat sink configured to thermally couple the plurality of solid state light-emitting sources and provide conduction of heat generated by the plurality of solid state light-emitting sources. The apparatus further includes an optical elements to collect, collimate, and combine the emissions from the plurality of solid state light-emitting sources into a combined beam of light to be optically coupled to the light guide.