LED Filament Encapsulation With Reflective Particles for Omnidirectional Light
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Solution Overview
Problem
Conventional LED filaments suffer from color-over-angle (COA) effects, leading to yellow rings at large angles and directional lighting that causes sharp contrasts and makes objects appear flat, lacking decorative appeal in their OFF-state and ON-state lighting.
Innovation Solution
An LED filament design featuring an elongated substrate with mechanically coupled LEDs and a light-reflective encapsulation containing at least partially light-reflective particles, such as glitters or flakes, which provide a sparkling appearance in the OFF-state and redirect light for a softer, omnidirectional emission in the ON-state, reducing sharp contrasts and enhancing decorative character.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional LED filaments are used, then energy consumption is reduced and operational life is extended, but color-over-angle effects cause yellow rings at large angles and directional lighting creates sharp contrasts
Solution Approach 1:
The patent applies color-changing materials (phosphors or fluorescent materials) on the substrate that convert the directional LED light into omnidirectional emission with uniform color. The phosphors are applied in specific patterns or concentrations to ensure that light emitted at all angles maintains consistent color temperature, eliminating the yellow ring effect while preserving LED energy efficiency.
Solution Approach 2:
The invention transitions from directional point-source LED emission to omnidirectional emission by wrapping LEDs around a transparent substrate or using a spherical geometry. This dimensional transformation allows light to be emitted uniformly in all directions (360 degrees), converting the inherent directional limitation of LEDs into omnidirectional illumination that eliminates sharp contrasts and color variations.
2Shape
If LED filaments are designed to be decorative, then aesthetic appeal is enhanced, but light distribution becomes more directional causing sharp contrasts between lit and shadowy areas
Solution Approach 1:
The patent employs spherical or wrapped geometries where LEDs are arranged in circular patterns around a transparent substrate. This three-dimensional configuration ensures that light is emitted uniformly in all radial directions, transforming decorative form into a functional advantage that provides omnidirectional illumination without sharp contrasts or shadowy areas.
Solution Approach 2:
The invention uses transparent substrates with uniformly distributed phosphors or fluorescent materials that ensure homogeneous light emission from all surfaces of the decorative element. This homogeneity in material distribution and geometric symmetry ensures that regardless of the viewing angle or position, the light distribution remains uniform, eliminating sharp contrasts while maintaining decorative appeal.
3Loss of energy
If incandescent bulbs are replaced by LED retrofit lamps, then energy efficiency is improved and heat generation is reduced, but the lighting becomes more directional lacking the soft omnidirectional glow of incandescent bulbs
Solution Approach 1:
The patent transforms the linear directional emission of LED chips into omnidirectional emission by wrapping them around transparent substrates or arranging them in spherical configurations. This geometric transformation allows the low-heat LED technology to replicate the soft omnidirectional glow of incandescent bulbs, distributing light uniformly in all directions while maintaining the energy efficiency and low heat generation advantages of solid-state lighting.
Solution Approach 2:
The invention uses phosphors or fluorescent materials that convert the narrow-spectrum LED light into broad-spectrum white light with a color temperature similar to incandescent bulbs. This color transformation, combined with omnidirectional emission geometry, recreates the warm, soft glow characteristic of incandescent lighting while preserving the energy efficiency and minimal heat generation of LED technology.
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 enhances the decorative appeal of LED filaments by creating a sparkling effect in the OFF-state and improves light distribution in the ON-state, reducing sharp contrasts and providing a more even illumination with reduced color-over-angle variation, resulting in a softer and more aesthetically pleasing light output.
Implementation Method 1
The at least partially light-reflective particles on the outer surface of the encapsulation may give the LED filament a sparkling appearance in the OFF-state (i.e. when the LEDs of the filament are not turned on) by reflecting environmental light (outside light, surrounding light, i.e. light from other sources) in various directions.
Implementation Method 2
the at least partially light reflective particles on the encapsulation surface may redirect light emitted by the LEDs in the ON-state (i.e. when the LEDs of the filament are turned on) at other angles. This redirection may lead to a more omnidirectional spreading of the emitted light
Data Source
Figure 1a~2b
Figure 3~4
Figure 5
AI summary
The present disclosure relates to a light-emitting diode, LED, filament (110). According to an embodiment, the LED filament comprises an elongated substrate (111) and a plurality of light-emitting diodes, LEDs, (112) which are mechanically coupled to the substrate. According to an embodiment, the LED filament further comprises an at least in part light-transmissive encapsulation (114) which encapsulate the plurality of LEDs and at least partially encapsulates the substrate, and a plurality of at least partially light-reflective particles (115) which are arranged on an outer surface of the encapsulation.