LED Light Source With Transmissive Reflector For Spherical Emission
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Solution Overview
Problem
Conventional incandescent light sources have a short lifespan, pose safety risks due to high temperature, and emit light unevenly, while LED replacements emit light into a hemisphere rather than a full sphere, lacking the decorative sparkling effects of incandescent lights.
Innovation Solution
A light source comprising a light unit with an LED and a light transmissive guide having a reflector with a transmitting portion and a reflecting surface, allowing light to be emitted uniformly into a full sphere, mimicking the intensity distribution of incandescent lights, and optionally featuring a color mixing rod and translucent envelope for enhanced performance and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If incandescent light sources are used, then light is emitted uniformly into a full sphere (4π sr), but the lifespan is short and safety risks arise due to high temperature
Solution Approach 1:
The patent replaces the thermal-mechanical incandescent filament system with an LED-based optical system. LEDs convert electrical energy directly to light without heating a filament, eliminating the mechanical/thermal failure modes of incandescent bulbs while achieving comparable or superior uniform light distribution through the light guide and reflector assembly
Solution Approach 2:
The patent changes the fundamental operating parameters from thermal radiation (incandescent) to electroluminescence (LED). This parameter change enables significantly lower operating temperatures, extended lifespan, and improved safety while maintaining the desired spherical light distribution pattern through optical design
2Reliability
If LED light sources are used, then lifespan is extended and efficacy is increased, but light is emitted only into a hemisphere (2π sr) rather than a full sphere
Solution Approach 1:
The patent introduces a light guide as an intermediary component between the LED and the surrounding space. The light guide receives light from the LED and redistributes it in multiple directions, while a reflector acts as a second intermediary to redirect light that would otherwise be lost, collectively transforming unidirectional LED emission into omnidirectional illumination
Solution Approach 2:
The patent uses the light guide's three-dimensional structure with its refractive index gradient to redirect light in multiple spatial dimensions. The reflector adds another dimensional aspect by reflecting light from the rear, effectively converting the LED's limited emission cone into full-sphere coverage through multi-dimensional light path manipulation
3Illumination intensity
If a reflector is added to redirect light, then spherical emission is achieved, but device complexity increases
Solution Approach 1:
The patent merges the light guide and reflector into an integrated optical assembly where the light guide's refractive properties and the reflector's reflective surface work together as a unified system. This merging reduces the number of separate components and simplifies assembly while achieving the desired spherical light distribution
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 long-lasting, safe, and uniformly lit LED light source that replicates the sparkling effects of incandescent lights, offering increased efficacy and adaptability to various lighting needs and environments.
Implementation Method 1
The light guide is arranged such that its index of refraction is higher than the index of refraction of the medium exterior to the light guide
Implementation Method 2
The reflector comprises a reflecting surface facing the output end and covering at least a portion of the output end
Data Source
Figure 1a~2
Figure 3
Figure 4a~4b
AI summary
The present invention relates to a light emitting diode, LED, light source that may be arranged for retrofitting into a luminaire employing an incandescent light source. The light source comprises a light guide into which light from one or more LEDs in a light unit arranged at one end of the light guide is injected, and a reflector having a reflecting surface arranged at the other end of the light guide and facing towards the light guide capable of reflecting light incident on the reflecting surface. According to the present invention, the reflector comprises at least one transmitting portion being arranged such that at least a portion of light incident on the at least one transmitting portion is transmitted through the reflector, for example a through hole extending along an axis, allowing for an almost viewing angle independent light intensity of the light source.