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, addressing COA issues and enhancing decorative character.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional LED filaments are used to provide directional lighting, then lighting efficiency is improved, but color uniformity deteriorates due to color-over-angle effects and sharp contrasts
Solution Approach 1:
The patent segments the lighting function by separating the LED light source from the light distribution function. Multiple LEDs are arranged along the filament, and each LED's light is independently managed through the translucent encapsulation and reflective particles, creating omnidirectional distribution while maintaining color uniformity across different viewing angles
Solution Approach 2:
The patent changes the light distribution parameters by using a translucent encapsulation instead of transparent, and adding reflective particles to the encapsulation. This transforms the directional light emission into omnidirectional emission, reducing color-over-angle effects and improving color uniformity while maintaining lighting efficiency
2Use of energy by moving object
If LED filaments provide directional light emission, then power consumption is reduced, but decorative appeal deteriorates in OFF-state due to lack of sparkle
Solution Approach 1:
The translucent encapsulation with reflective particles serves multiple functions: it diffuses light during ON-state for omnidirectional emission, and reflects ambient light during OFF-state to create sparkle effect. This single component structure provides both functional lighting and decorative appeal without increasing power consumption
Solution Approach 2:
The patent changes the optical parameters of the encapsulation from transparent to translucent, and adds reflective particles, enabling the material to interact differently with light in ON-state versus OFF-state. This creates dual functionality: functional lighting when powered and decorative sparkle when unpowered, without additional energy consumption
3Illumination intensity
If transparent encapsulation is used in LED filaments, then light transmission is improved, but light distribution deteriorates due to sharp contrasts and directional emission
Solution Approach 1:
The patent changes the optical parameter of the encapsulation from transparent to translucent, which diffuses the light while maintaining high transmission. This transforms the sharp directional light into soft omnidirectional light, improving light distribution uniformity and reducing color-over-angle effects while preserving light transmission efficiency
Solution Approach 2:
The translucent encapsulation acts as an intermediary between the LED light source and the surrounding environment. It mediates the light transmission by diffusing the light in multiple directions, creating uniform light distribution and soft lighting effects while maintaining high overall transmission
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 providing a sparkling appearance when off and a softer, more evenly distributed light when on, reducing sharp contrasts and improving color rendering index, while maintaining optimal light coverage and reflectivity.
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
Further, 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
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.