LED Optic Redirecting Light via Refraction and Reflection
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Solution Overview
Problem
Conventional light emitting diodes (LEDs) lack the capability to efficiently manage light distribution, particularly in applications like street lighting, where it is necessary to bias light towards the street rather than houses, leading to inefficient energy use and suboptimal illumination patterns.
Innovation Solution
An optical system comprising a light emitting diode with an associated optic that utilizes total internal reflection and refractive surfaces to redirect light from the house side to the street side, enhancing the illumination intensity on the desired area by manipulating light rays through sequential refraction and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional unbiased LEDs are mounted facing down over the sidewalk, then the LED structure is simple and easy to install, but the light distribution is inefficient as equal amounts of light are cast towards both the street and houses
Solution Approach 1:
The patent introduces an optical element as an intermediary component between the LED and the environment. This optical element selectively redirects light rays based on their origin direction, serving as a mediator that transforms the unbiased light distribution into a biased distribution favoring the street side while maintaining the simple downward-facing LED mounting configuration.
Solution Approach 2:
The optical element applies different optical properties to different regions: the first surface has a first region with a first refractive index and a second region with a second refractive index. This local differentiation of optical properties enables selective redirection of light from different directions, improving energy efficiency without complicating the overall LED mounting structure.
2Loss of energy
If the optical element uses multiple regions with different refractive indices to redirect light, then light distribution efficiency is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functional regions into a single integrated optical element. The first and second regions with different refractive indices are combined in one component that performs both refraction and reflection functions, eliminating the need for separate optical components and reducing overall device complexity while maintaining high light redirection efficiency.
Solution Approach 2:
The optical element serves multiple functions simultaneously: it acts as a refractive element for light from the first direction, a reflective element for light from the second direction, and a beam-forming element. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while achieving efficient light management.
3Loss of energy
If total internal reflection is used to redirect light, then energy conservation is improved, but the requirement for precise optical geometry increases complexity
Solution Approach 1:
The patent changes the refractive index parameter across different regions of the optical element to achieve total internal reflection at specific interfaces. By carefully selecting and varying the refractive indices of the first and second regions, the design achieves efficient light redirection through total internal reflection while the gradual parameter transition simplifies manufacturing compared to sharp geometric discontinuities.
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 system effectively transforms light distribution, conserving energy by redirecting light from houses to streets, thereby improving illumination efficiency and reducing energy consumption in various lighting applications.
Implementation Method 1
a first refractive surface forming an interface between the first medium and the second medium and that receives light from the light emitting diode and that redirects a section of the light from a first direction toward a second direction
Implementation Method 2
a second refractive surface forming an interface between the second medium and the first medium and that applies total internal reflection to redirect the section of light towards a desired location
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
A light source, for example a light emitting diode, can emit light and have an associated optical axis. The source can be deployed in applications where it is desirable to have illumination biased laterally relative to the optical axis, such as in a street luminaire where directing light towards a street is beneficial. The source can be coupled to an optic that comprises an inner surface facing the source and an outer surface that is opposite the inner surface. The inner surface can comprise a refractive surface that receives light headed away from the optical axis of the light source, for example opposite the street. The refractive surface can form the received light into a beam. The outer surface of the optic can reflect the beam back across the optical axis, for example so that light headed away from the street is redirected towards the street.