LED Filament Structure With Deposited Conductor for Higher Lumen Density
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Solution Overview
Problem
LED filament lamps face issues such as structural weakness leading to breakage, limited lumen per unit length, and high overall thickness due to conventional wire bonding processes, which affect their applicability and efficiency in providing wide-angle illumination.
Innovation Solution
A lighting device with a light-emitting diode filament featuring a chip strip structure on a substrate, connected by a conductor layer formed through deposition, allowing for a continuous strip-shaped structure that reduces the distance between deposition units and increases lumen per unit length, while using a light conversion unit to enhance light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional wire bonding process is used to connect LED chips, then electrical connection is achieved, but the filament structure becomes thick and prone to breakage
Solution Approach 1:
The patent replaces the mechanical wire bonding process with a deposition-based conductor layer formation. Instead of using physical wires to connect LED chips, a continuous conductor layer is deposited directly on the substrate to electrically connect the chips, eliminating the need for separate wire bonding steps and reducing overall filament thickness while improving structural integrity.
Solution Approach 2:
The patent merges the electrical connection function and structural support function into a single integrated conductor layer. The conductor layer serves both as the electrical pathway connecting LED chips and as part of the structural framework of the filament, eliminating the need for separate wire bonding components and reducing filament thickness.
2Ease of manufacture
If LED chips are spaced far apart for wire bonding, then manufacturing is easier, but lumen per unit length decreases
Solution Approach 1:
The deposition-based conductor layer formation enables closer spacing of LED chips compared to wire bonding. The continuous deposited conductor layer can be formed with finer precision and smaller feature sizes than wire bonds, allowing chips to be placed closer together while maintaining reliable electrical connections, thereby increasing lumen per unit length.
3Shape
If LED filament is made thin to match tungsten filament shape, then aesthetic appearance is improved, but structural strength decreases and breakage increases
Solution Approach 1:
The patent employs a composite structure consisting of a substrate, deposition units (LED chips), connecting layers, and a conductor layer. This multi-layer composite architecture provides enhanced mechanical strength and structural integrity while maintaining a thin overall profile that mimics the appearance of traditional tungsten filaments, reducing breakage risk.
Solution Approach 2:
The patent utilizes thin film deposition techniques to create the conductor layer and connecting layers, which provide structural support and electrical connectivity within a thin profile. The deposited layers form a flexible yet strong structure that maintains the thin filament shape while preventing breakage.
4Illumination intensity
If more LED chips are placed per unit length, then lumen per unit length increases, but manufacturing complexity increases
Solution Approach 1:
The deposition-based connection method simplifies manufacturing for high-density chip arrangements. Instead of performing complex wire bonding operations on closely spaced chips, the continuous conductor layer is deposited in a single or few steps, automatically connecting all chips along the filament. This reduces manufacturing complexity while enabling higher chip density and increased lumen per unit length.
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 provides a stable electrical connection, reduces breakage risk, and enhances light output by increasing the number of deposition units per unit length, improving the filament's structural integrity and illumination efficiency.
Implementation Method 1
a conductor layer configured to electrically connect the deposition units
Data Source
AI summary
A lighting device, including: a lamp housing and a lamp cap connected to each other and formed a closed space; at least one light-emitting diode filament disposed in the closed space; and a stem connected to the lamp cap and electrical conducted with the light-emitting diode filament, wherein the light-emitting diode filament includes: a chip strip structure; a light conversion unit wrapping the chip strip structure; and electrodes located at two ends of the chip strip structure respectively and electrically connected thereto, wherein at least part of the electrodes are wrapped in the light conversion unit; the chip strip structure includes a substrate with a first end and a second end, and a deposition segment located between the first end and the second end; and the deposition segment includes a plurality of deposition units with a connecting layer disposed therebetween, and a conductor layer electrically connects the deposition units.