LED Filament Lamp Scattering Profile for Candlelight Appearance

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Solution Overview

Problem

LED filament lamps lack the aesthetic appeal of candlelight, appearing static and unattractive compared to the vivid, warm, and romantic light of open flames, while candles pose a fire risk.

Innovation Solution

An LED filament lamp with a variable light intensity profile achieved by varying the thickness and concentration of a light scattering material along its length, mimicking the appearance of a candle flame while ensuring safety and longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If LED filaments are used to replace incandescent lamps, then energy efficiency and operational life are improved, but aesthetic appeal and visual warmth are worsened

Engineering Contradiction:
Improvepower consumptionVSAvoidaesthetic appeal
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent applies local quality by varying the thickness of the encapsulant along the LED filament length. Different sections of the filament have different encapsulant thicknesses, creating zones with different light scattering properties. This produces a non-uniform light intensity distribution that mimics the visual characteristics of candlelight, thereby improving aesthetic appeal while maintaining LED energy efficiency

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes physical parameters of the encapsulant material, specifically its thickness and the concentration of light scattering particles, along the length of the LED filament. These parameter variations create the desired light intensity profile that resembles candlelight, resolving the contradiction between LED efficiency and aesthetic appeal

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If LED filaments have uniform structure, then manufacturing is simplified, but light intensity uniformity is worsened

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight intensity uniformity
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The encapsulant thickness is deliberately varied along the LED filament length, creating local differences in light scattering. This non-uniform structure produces the desired candlelight-like effect while remaining compatible with standard manufacturing processes, thus balancing manufacturing simplicity with controlled light intensity variation

Inventive Principle:
Principle #3Local quality

3Illumination intensity

If candles are used for illumination, then aesthetic appeal is improved, but safety is worsened

Engineering Contradiction:
Improveaesthetic appealVSAvoidfire risk
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent creates an artificial copy of candlelight appearance using LED technology. By manipulating the light scattering properties of the encapsulant, the LED filament reproduces the visual characteristics of candlelight including its warm glow and intensity variations, without the harmful open flame, thus achieving aesthetic appeal while eliminating fire risk

Inventive Principle:
Principle #26Copying

4Illumination intensity

If LED filament structure is modified to improve light distribution, then aesthetic appeal is improved, but device complexity is worsened

Engineering Contradiction:
Improvelight distributionVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent modifies the encapsulant thickness parameter along the LED filament length to control light scattering and achieve desired light distribution. This approach improves aesthetic appeal through parameter variation rather than adding complex structural elements, thus minimizing increases in device complexity

Inventive Principle:
Principle #35Parameter changes

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 LED filament lamp generates an attractive and appealing light effect that combines the benefits of LED lighting with the aesthetic of candlelight, offering improved safety and cost-efficiency over candles, with a longer operational life and easier recycling.

Implementation Method 1

The encapsulant comprises a light scattering material. At least one of (i) the thickness of the encapsulant, and (ii) the concentration of the light scattering material in the encapsulant, along the LED filament length increases over at least two adjacent first LEDs and decreases over at least two adjacent second LEDs different from the at least two adjacent first LEDs.

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4031802B1LED filament lamp
Publication Date: 2024.03.20 SIGNIFY HOLDING BV
  • EP4031802B1 patent drawingFigure 1a~1f
  • EP4031802B1 patent drawingFigure 2a~2b
  • EP4031802B1 patent drawingFigure 3a~3f

AI summary

There is provided a light emitting diode, LED, filament lamp (100) which provides LED filament lamp light (100'). The LED filament lamp (100) comprises at least one LED filament (101) which has a LED filament length (L) which extends from a first end (1003) to a second end (1004). The at least one LED filament (101) provides LED filament light (101') and comprises an array (102) of a plurality of LEDs (103) and an encapsulant (104). The array (102) of a plurality of LEDs (103) provide LED light (103') and extend along the LED filament length (L). The encapsulant (104) is at least partially enclosing the plurality of LEDs (103). The encapsulant (104) comprises a light scattering material (105). In the direction from the first end (1003) to the second end (1004) at least one of (i) the thickness (TL) of the encapsulant (104), and (ii) the concentration (CL) of the light scattering material (105) in the encapsulant (104), along the LED filament length (L) increases over at least two adjacent first LEDs (106) and decreases over at least two adjacent second LEDs (107) different from the at least two adjacent first LEDs (106), and wherein the thickness (TL) and/or concentration (CL) firstly increases and secondly decreases at least along a portion of the LED filament length (L).