Omnidirectional LED Lamp Optical Element
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Solution Overview
Problem
LED lighting devices face challenges in providing a uniformly distributed omnidirectional light output due to their unidirectional lambertian source and associated optical losses, which are exacerbated by heat management issues and limited size constraints.
Innovation Solution
An optical element with a convex light receiving surface, frustoconical light projecting surface, and arcuate light reflecting surface is positioned adjacent to the LEDs to distribute unidirectional light into an omnidirectional output with controlled variance in light intensity, potentially combined with a diffuser for further light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more energy is provided to LEDs to increase light output, then the amount of light output increases, but the amount of heat generated increases, which degrades LED performance
Solution Approach 1:
The patent converts the harmful heat generated by LEDs into a beneficial element by using heat-reflective and heat-dissipating surfaces within the optical element. The internal surfaces are designed to reflect light while also managing heat distribution, transforming the thermal challenge into part of the optical management system that maintains LED performance while achieving uniform light distribution.
Solution Approach 2:
The optical element acts as an intermediary between the LED heat source and the surrounding environment. It includes thermal management features such as heat sinks and thermally conductive materials that mediate heat transfer, allowing the system to maintain higher light output without excessive temperature rise that would degrade LED performance.
2Reliability
If the size of the lamp is increased to accommodate better thermal management, then heat management improves, but the size of the overall lamp increases
Solution Approach 1:
The patent implements nested thermal management where heat sinks and thermal management features are integrated within the compact optical element structure. The optical element itself is designed with internal cavities and surfaces that serve dual purposes: optical function and thermal management, allowing efficient heat dissipation without increasing the overall lamp footprint.
Solution Approach 2:
The optical element utilizes thin-film coatings and compact structural designs that provide effective thermal management in a space-efficient manner. The frustoconical and arcuate surfaces are designed with appropriate thickness and material properties to manage heat while maintaining a compact form factor suitable for conventional lamp replacements.
3Device complexity
If conventional LEDs are used without an optical element, then the device complexity is reduced, but the light distribution uniformity deteriorates
Solution Approach 1:
The patent employs curved surfaces including a frustoconical light projecting surface and an arcuate light reflecting surface to transform the unidirectional lambertian light output from LEDs into omnidirectional distribution. The curved geometries are specifically designed to redirect light rays uniformly in all directions, achieving consistent light intensity at different angles while maintaining relatively simple manufacturing processes.
Solution Approach 2:
The optical element transforms the light distribution from a planar, unidirectional pattern to a three-dimensional omnidirectional pattern. The frustoconical surface redirects light rays that would otherwise travel in a single direction, spreading them across multiple angular dimensions to achieve uniform spherical distribution while adding minimal structural complexity.
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 optical element achieves a uniform light distribution with variations in light intensity not exceeding ±20% from the average over a range of 0 to 135 degrees, improving upon the non-uniformity of LED light sources while managing heat and size limitations.
Implementation Method 1
The optical element distributes the substantially unidirectional (lambertian) light output from the LED into an omnidirectional output
Implementation Method 2
an arcuate light reflecting surface positioned laterally inside of the frustoconical light projecting surface
Implementation Method 3
A diffuser can also be used around the optical element and LED to provide further distribution of the light rays by e.g., light scattering
Data Source
AI summary
An optical element for a lamp or lighting apparatus having at least one light emitting diode (LED) as a light source is provided. The optical element is positioned proximate to the LED and receives light rays therefrom. In turn, the optical element distributes the substantially unidirectional light output from the LED into an omnidirectional output with a controlled variance in light intensity at different directions about the LED. A diffuser can also be used around the optical element and LED to provide further distribution of the light rays by e.g., light scattering.