High Radiance LED Light Engine with Tapered Optics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current surgical and microscopy lighting technologies, such as tungsten, metal halide, xenon, and mercury lamps, face issues with short lifetimes, high voltage requirements, toxicity concerns, and inadequate color rendering index (CRI) and correlated color temperature (CCT) stability, while commercially available LED solutions suffer from low CRI and non-adjustable CCT.
Innovation Solution
A high radiance LED light source with closed-loop control over multiple colors, utilizing chip-on-board technology, diamond heat spreaders, and non-imaging collection optics with dichroic beam couplers, providing stable CRI and CCT over a wide range and maintaining high radiance through improved thermal management and optical power monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If tungsten or tungsten halogen lamps are used, then long lifetime is achieved, but radiance is insufficient for demanding surgical applications
Solution Approach 1:
The patent transitions from thermal radiation sources (tungsten) to electroluminescence sources (LEDs), fundamentally changing the physical mechanism of light generation. This parameter change enables achieving both high radiance and long lifetime simultaneously, as LEDs operate at lower temperatures and have no filament degradation issues.
Solution Approach 2:
The patent replaces the mechanical/thermal system (tungsten filament heating) with an electrical/optical system (LED electroluminescence). This substitution eliminates the fundamental limitations of thermal sources, enabling high radiance without the short lifetime associated with high-temperature filament operation.
2Illumination intensity
If metal halide, xenon, or mercury lamps are used, then high radiance is achieved, but toxic mercury is used which is being forced out by regulatory agencies
Solution Approach 1:
The patent eliminates the harmful element (mercury) entirely while maintaining or improving performance. By using LED technology with phosphor conversion, the system achieves high radiance without any toxic materials, turning the harmful dependency on mercury into a benefit of environmentally friendly operation.
Solution Approach 2:
The patent adopts solid-state LED technology which is inherently more reliable and longer-lived than gas discharge lamps. The elimination of fragile glass envelopes and toxic gases makes the system both safer and more durable, effectively replacing short-lived hazardous lamps with long-lived safe alternatives.
3Illumination intensity
If arc lamps are used, then high radiance is achieved, but arc flicker necessitates homogenizing optics which further reduces source radiance
Solution Approach 1:
The patent replaces the unstable arc discharge mechanism with stable LED electroluminescence. LEDs provide inherently stable light output without arc flicker, eliminating the need for complex homogenizing optics that reduce radiance. The electrical-to-optical conversion in LEDs is far more stable than thermal-to-optical conversion in arc lamps.
Solution Approach 2:
The patent ensures continuous stable operation by eliminating the arc start-stop and flicker characteristics of gas discharge lamps. LEDs provide continuous steady-state operation, maintaining consistent radiance output without the interruptions and fluctuations inherent in arc lamp operation.
4Duration of action of stationary object
If commercially available white LED systems are used, then long life and high radiance are achieved, but CRI is very low on the order of 65 to 80
Solution Approach 1:
The patent segments the white light generation into multiple independent LED chips with different wavelengths (blue, cyan, green, yellow-green, red). This segmentation allows independent optimization of each wavelength component to achieve both high radiance and high CRI, rather than relying on a single white LED chip with fixed phosphor conversion.
Solution Approach 2:
The patent uses a composite approach by combining multiple LED chip types with different spectral characteristics. This composite LED array, coupled with appropriate phosphors and optical elements, creates a synergistic system that achieves superior CRI and radiance compared to individual white LED chips, while maintaining the long lifetime advantage of LED technology.
5Illumination intensity
If commercially available white LED systems are used, then high radiance is achieved, but CCT is not stable as it generally increases with increasing intensity
Solution Approach 1:
The patent segments the spectral output into multiple independently controllable wavelength components from different LED chips. This segmentation enables independent adjustment of each wavelength's intensity, allowing precise control and stabilization of overall CCT regardless of total intensity changes, eliminating the CCT drift inherent in single-white-LED systems.
Solution Approach 2:
The patent implements dynamic control of multiple LED chip intensities through closed-loop feedback. By actively adjusting the drive current to each LED chip type based on measured output, the system dynamically maintains stable CCT across varying intensity levels, transforming the static CCT-drift problem into a controllable dynamic system.
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 offers significantly longer lifespan (up to 20,000 hours), higher radiance, and improved color rendering capabilities, surpassing existing technologies in surgical and microscopy applications with stable CRI and CCT, while being free from toxic materials.
Implementation Method 1
A first plurality of light emitting diode (LED) die having a first color are mounted to a heat spreader... A second plurality of LED die having a second color are mounted to the heat spreader
Implementation Method 2
A first plurality of light emitting diode (LED) die having a first color are mounted to a heat spreader
Implementation Method 3
High efficiency non-imaging collection optics are coupled to the LEDs to efficiently capture all the light the LEDs emit and reformat it as an output
Implementation Method 4
High efficiency non-imaging collection optics are coupled to the LEDs to efficiently capture all the light the LEDs emit and reformat it as an output
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Described is a light emitting diode (LED) high radiance illumination system that includes at least one LED die and a tapered collection optic. An aperture in a reflective surface at the output end of the tapered collection optic recovers light is configured to emit light to an adjacent optical fiber bundle. The reflective surface surrounding the aperture reflects light back through the tapered collection optic, resulting in increased radiance. The system provides uniform high intensity in near and far fields and is suitable for applications including surgical and microscopy illumination with high color rendering index, and stable and adjustable intensity and correlated color rendering. Illumination can include one or more colors, including white light. The system has improved thermal and optical performance and is generally more compact and lower in cost relative to conventional systems.