LED Illumination Device with Coplanar Lens Array
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Solution Overview
Problem
Fiber-optic light sources face limitations such as low light transmission efficiency, non-uniform light distribution, and thermal constraints due to the Etendue principle and the use of LEDs, which require multiple LEDs and complex optics to achieve desired light intensity and uniformity.
Innovation Solution
A design featuring multiple LEDs mounted on a substrate with a lens array to collect and collimate light, a focusing lens to align with the fiber optic bundle, and an optional diffusing element to enhance light uniformity, optimizing the arrangement of LEDs and lenses for increased light capture and reduced heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple LEDs are used to increase light output, then light intensity is improved, but device complexity increases
Solution Approach 1:
The illumination device segments the light source into multiple individual LEDs arranged in an array, with each LED independently coupled to the fiber optic bundle. This segmentation allows the system to achieve high total light output by combining multiple light sources while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The patent merges multiple LED light sources and their individual optical paths into a single integrated system that couples to the fiber optic bundle. By combining the light output from multiple LEDs through a common coupling mechanism, the system achieves high illumination intensity without proportionally increasing overall device complexity.
2Loss of energy
If focusing optics are used to improve light coupling efficiency, then light transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates complex focusing optics from the light coupling system. Instead of using lenses or mirrors to focus light, the invention directly couples each LED to the fiber optic bundle, achieving efficient light transfer through geometric alignment and proximity rather than optical focusing elements.
Solution Approach 2:
The patent introduces a simple intermediate coupling structure that facilitates direct light transfer from LEDs to the fiber optic bundle without requiring complex focusing optics. This intermediary mechanism enables efficient light coupling through straightforward geometric arrangement rather than optical focusing.
3Illumination intensity
If a large number of LEDs are used to overcome Etendue limitations, then light output is improved, but heat generation increases
Solution Approach 1:
The patent segments the high-power illumination task across multiple individual LED elements, distributing the heat generation across many separate sources rather than concentrating it in a single high-power source. This segmentation allows for better thermal management through distributed heat dissipation.
Solution Approach 2:
The patent arranges multiple LEDs in a two-dimensional array configuration, spreading the heat-generating elements across a larger spatial footprint. This dimensional distribution reduces heat concentration at any single point and improves overall thermal management of the illumination 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 significantly increases light output and achieves uniform color and intensity distribution, overcoming the limitations of traditional fiber-optic systems by aligning and overlaying LED images onto the fiber optic bundle, resulting in improved light transfer efficiency and reduced thermal constraints.
Implementation Method 1
a lens array to collect and collimate light from the LEDs
Implementation Method 2
a focusing lens to focus light onto the input end of a fiber-optic bundle
Implementation Method 3
For most fiber-optic bundles composed of clad glass fibers, that acceptance half-angle is approximately 33°, corresponding to a numerical aperture (NA) of approximately 0.55
Implementation Method 4
an optional light diffusing element, a device to support and align the LEDs and optical elements
Data Source
AI summary
A device comprising a plurality of LEDs arranged in a coplanar array, the coplanar array comprising an LED at the center and LEDs positioned radially symmetrically around the LED at the center, and wherein the central axes of the LEDs are arranged to be parallel to each other; a one-piece lens array collimating light from the LEDs, the lens array comprising a plurality of coplanar lens tiles, the coplanar lens tiles comprising a lens tile at the center and lens tiles positioned radially symmetrically around the lens tile at the center, and wherein the central axis of each of the lens tiles is aligned with the central axis of a corresponding LED; and a focusing lens converging the collimated light from the lens array into a single image in a focal plane, wherein the central axis of the focusing lens is aligned with the central axis of the lens array.