LED Filament Light Conversion Layer for 360 Illumination
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Solution Overview
Problem
Conventional LED light sources face challenges in achieving wide-angle illumination and color rendering index due to directional light emission, stress concentration during bending, and reduced luminous flux from low red phosphor conversion rates, along with flicker issues from AC to DC conversion and heat effects on electrolytic capacitors.
Innovation Solution
An LED filament design with a light conversion layer comprising a top and carrying layer, including a transparent layer for heat dissipation and structural reinforcement, and conductive sections for stress distribution, along with a specific phosphor composition for enhanced color rendering and luminous efficiency, and a gas filling to improve heat dissipation and longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LED chips are fixed on a narrow glass substrate to achieve 360° full-angle illumination, then wide-angle illumination is improved, but the directional light emission characteristic of conventional LEDs cannot be overcome
Solution Approach 1:
The patent transitions from conventional planar LED mounting to a three-dimensional filament structure where LED chips are arranged along a curved or spiral path within the bulb. This spatial reconfiguration enables light emission from multiple angles simultaneously, achieving 360° illumination without requiring complex multi-directional optical systems.
Solution Approach 2:
The LED filament is designed with a curved or spiral geometry rather than a straight line, allowing the light source to distribute illumination more evenly in all directions. The curved path of the filament ensures that light is emitted from various angular positions, creating omnidirectional lighting效果.
2Adaptability or versatility
If FPC substrate is used to enable filament bending, then flexibility is improved, but coefficient of thermal expansion mismatch causes LED chip displacement or degumming
Solution Approach 1:
The patent changes the material parameters of the substrate, specifically selecting materials with thermal expansion coefficients that match both the LED chips and the encapsulant resin. This parameter optimization prevents thermal stress-induced failures during bending operations while maintaining the required flexibility for various filament configurations.
Solution Approach 2:
The patent employs composite substrate structures that combine materials with complementary properties. The composite design provides both the flexibility needed for bending and the thermal stability required to prevent chip displacement, reconciling the conflicting requirements through material composition rather than single-material solutions.
3Illumination intensity
If red phosphor is added to increase color rendering index, then color rendering is improved, but total luminous flux decreases due to low conversion rate
Solution Approach 1:
The patent applies different phosphor compositions to different regions or layers of the encapsulant. By strategically placing red phosphor in specific zones where it can effectively convert blue light without excessively reducing overall luminous flux, the design achieves improved color rendering while minimizing the negative impact on total light output.
Solution Approach 2:
The patent uses composite phosphor systems combining multiple phosphor materials with different emission characteristics. This composite approach allows simultaneous optimization of color rendering index and luminous flux by selecting phosphors that work synergistically, where the combined conversion efficiency exceeds that of individual phosphors alone.
4Ease of operation
If AC to DC conversion is implemented to drive LEDs, then proper electrical drive is achieved, but flicker and heat effects on electrolytic capacitors occur
Solution Approach 1:
The patent replaces traditional electrolytic capacitor-based filtering with solid-state capacitor alternatives or different circuit topologies that eliminate or reduce flicker and heat generation issues. This substitution removes the problematic components while maintaining the necessary AC-to-DC conversion functionality for LED operation.
Solution Approach 2:
The patent optimizes the electrical parameters of the driving circuit, including switching frequency, current ripple, and thermal management characteristics. By carefully selecting operating parameters, the design achieves stable LED drive with minimal flicker and reduced thermal stress on capacitive components, extending system reliability.
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 achieves 360° illumination, high color rendering index, and improved luminous efficiency with reduced heat and stress, while minimizing flicker and extending service life through effective heat dissipation and structural reinforcement.
Implementation Method 1
a light conversion layer, wrapping the LED section and parts of the electrodes, and comprising a top layer and a carrying layer... the light conversion layer has a first end and a second end opposite to the first end... transparent layer for heat dissipation
Implementation Method 2
a specific phosphor composition for enhanced color rendering and luminous efficiency... wrapping the LED section and parts of the electrodes, and comprising a top layer and a carrying layer
Implementation Method 3
conductive sections for stress distribution... electrically connected to the LED section
Implementation Method 4
a gas filling to improve heat dissipation and longevity
Implementation Method 5
a gas filling to improve heat dissipation and longevity
Data Source
AI summary
This application relates to the field of lighting, and discloses an LED filament including: at least one LED section, each LED section including at least two LED chips, adjacent LED chips being electrically connected to each other; electrodes, electrically connected to the LED section; and a light conversion layer, wrapping the LED section and parts of the electrodes, and including a top layer and a carrying layer, the carrying layer including a base layer and a transparent layer, the base layer including an upper surface and a lower surface opposite to each other, the upper surface of the base layer being in contact with a part of the top layer, and a part of the lower surface of the base layer being in contact with the transparent layer. This application has the characteristics of uniform light emission and good heat dissipation effect.