LED Light Source with Curved Reflector for Spherical Distribution

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Solution Overview

Problem

Conventional incandescent light sources have short lifespans and safety concerns due to high temperatures, and LED light sources typically emit light into a hemisphere rather than a full sphere, limiting their application in retrofitting luminaires that require uniform light distribution.

Innovation Solution

A light source comprising a light unit with LEDs, a reflector, and a light guide with a higher refractive index than the surrounding medium, featuring a reflecting surface that can be concave or convex to achieve a spatial intensity distribution similar to incandescent light sources, allowing light to be emitted uniformly into a full sphere and adapted for various lighting applications.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If LED light sources are used to replace incandescent light sources, then energy efficiency and lifespan are improved, but light distribution uniformity deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlight distribution uniformity
Core Design Contradiction:
Loss of energyVSIllumination intensity

Solution Approach 1:

The patent employs a light guide with a curved or spherical output surface to redirect light from the LED into a full-sphere distribution pattern. The curved geometry transforms the inherently directional LED emission into omnidirectional light distribution, resolving the contradiction between LED energy efficiency and uniform light distribution requirements.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent introduces a light guide as an intermediary component between the LED and the surrounding space. This light guide acts as a mediator that receives directional light from the LED and redistributes it uniformly in all directions, enabling LED replacement in applications requiring spherical light distribution while maintaining energy efficiency benefits.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If conventional incandescent light sources are used, then uniform light distribution is achieved, but temperature and safety issues worsen

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidthermal stress
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent replaces the thermal-mechanical incandescent filament system with an electroluminescent LED system coupled with optical elements. This substitution eliminates the high-temperature filament while achieving the same uniform light distribution function through optical design, thereby resolving the temperature and safety issues associated with conventional incandescent sources.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If LEDs emit light into a hemisphere only, then device simplicity is maintained, but application versatility deteriorates

Engineering Contradiction:
Improvedevice simplicityVSAvoidapplication versatility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent designs a light guide system that can achieve full-sphere light distribution, making the LED-based light source universally applicable to various luminaire types that previously required incandescent bulbs. This multi-functional capability allows a single LED design to replace multiple different light sources across different applications, enhancing versatility without significantly increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 retrofit LED light source with improved optical efficiency and safety by mimicking the light distribution of incandescent sources, offering increased efficacy and versatility in lighting applications while reducing thermal stress and enhancing visual comfort.

Implementation Method 1

a light transmissive light guide (8) having an input end (8a), an output end (8b), and a central region (8c) therebetween, the light guide extending along an axial direction... 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

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a reflector (9) arranged adjacent to the output end (8b) and comprising a reflecting surface (10) facing the output end and covering at least a portion of the output end. The reflecting surface is arranged such that at least a portion of the reflecting surface is one of concave and convex

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2386045B1Light source with LEDS, light guide and reflector
Publication Date: 2015.06.17 KONINKLIJKE PHILIPS NV
  • EP2386045B1 patent drawingFigure 1a~2b
  • EP2386045B1 patent drawingFigure 3a~3b
  • EP2386045B1 patent drawingFigure 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 reflecting surface can be arranged in a number of exemplary ways such as to enable the light emitted from the light source to have a spatial intensity distribution that is similar to the light intensity distribution of an incandescent light source.