LED Candle Bulb Light Guide Radial Distribution

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Solution Overview

Problem

Semiconductor light emitting devices struggle to emulate the appearance of natural candle light due to design constraints, such as the need for a heat sink, which limits their ability to produce a predominantly radial light distribution characteristic of candle flames.

Innovation Solution

A semiconductor light emitting bulb design featuring a light emitting device at the base with a light guide that directs light to a diffusion element above the base, creating a predominantly radial light distribution pattern that mimics candle light, including a combination of conic and cylindric diffusion elements and a reflective layer to enhance the halo effect and teardrop shape of the flame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If semiconductor light emitting devices are used to emulate candle light, then energy efficiency is improved, but the ability to produce predominantly radial light distribution deteriorates due to heat sink requirements

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlight distribution pattern
Core Design Contradiction:
Use of energy by moving objectVSShape

Solution Approach 1:

A light guide is introduced as an intermediary component between the LED light source and the external environment. The light guide redirects light that would normally travel upward toward the heat sink instead, channeling it to illuminate the diffuser element and produce the desired radial candle-like light distribution pattern.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention redirects light propagation from a primarily vertical dimension (upward toward heat sink) to a radial three-dimensional distribution pattern. By using the light guide to redirect light at different angles and the diffuser element to scatter light in multiple directions, the system achieves predominant radial light distribution characteristic of candle flames.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Temperature

If a heat sink is mounted close to the light emitting device, then heat dissipation is improved, but the emulation of natural candle light appearance deteriorates

Engineering Contradiction:
Improveheat dissipationVSAvoidcandle light appearance
Core Design Contradiction:
TemperatureVSShape

Solution Approach 1:

The heat sink is extracted from its conventional position immediately adjacent to the LED and relocated to the base of the bulb. This spatial separation allows the upper portion of the bulb to be designed without heat dissipation constraints, enabling the implementation of light guides and diffuser elements that produce authentic candle-like visual appearance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The light guide serves as a mediator that decouples the thermal management function from the optical emission function. It allows the heat sink to remain at the base while still enabling effective light distribution through the diffuser element, resolving the conflict between heat dissipation requirements and aesthetic appearance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Shape

If conventional incandescent bulbs are configured to suspend filament above base, then point source emission is improved, but energy efficiency deteriorates

Engineering Contradiction:
Improvepoint source emissionVSAvoidenergy efficiency
Core Design Contradiction:
ShapeVSUse of energy by moving object

Solution Approach 1:

The invention creates an optical copy or illusion of a suspended point source by using a light guide to redirect light to appear as if emanating from above the base, combined with a diffuser element that scatters light radially. This replicates the visual appearance of incandescent candle emulation without using actual thermal radiation from a filament.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The mechanical/thermal system of incandescent filament heating and radiation is replaced with a semiconductor LED system combined with optical elements (light guide and diffuser). This substitution maintains the desired optical output characteristics while dramatically improving energy efficiency by eliminating inefficient thermal conversion.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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 bulb effectively emulates the appearance of a natural candle light source while being mounted on a remote heat sink, providing a more realistic and efficient light distribution pattern that approximates the radial and diffused light output of a candle flame.

Implementation Method 1

a light guide that guides the emitted light to a diffusion element above the base of the bulb

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Implementation Method 2

a diffusion element above the base of the bulb that diffuses the light so as to emulate the predominantly radial light produced by a candle

Methodology Applied
Scientific EffectLight diffusion: Scattering

Implementation Method 3

a reflective layer to enhance the halo effect and teardrop shape of the flame

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2745039B1Candle light LED light bulbs
Publication Date: 2019.06.26 SIGNIFY HOLDING BV
  • EP2745039B1 patent drawingFigure 1~4
  • EP2745039B1 patent drawingFigure 3A~3E

AI summary

A light bulb includes a light emitting device at the base of the bulb and a light guide (320) that guides the emitted light to a diffusion element (330) above the base of the bulb. The diffusion element is configured to diffuse the light so as to emulate the predominantly radial light distribution pattern produced by a candle. A variety of features for the diffusion element, as well as features of the base and bulb, are presented that enhance the candle-like effects.