LED Filament Light-Blocking Wall for Optical Cross-Talk Reduction
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Solution Overview
Problem
LED filaments with RGB and white LEDs on the same PCB or FPC surface experience unwanted optical cross-talk, reducing the color-gamut area and resulting in unsaturated color appearance.
Innovation Solution
Incorporating at least one light-blocking wall between the first and second LED filament portions, such as between white and RGB LEDs, to prevent optical cross-talk by blocking light where needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RGB and white LEDs are placed on the same PCB or FPC surface, then the device complexity is reduced and manufacturing is simplified, but optical cross-talk occurs between LED strings causing color gamut reduction and unsaturated color appearance
Solution Approach 1:
The LED filament is divided into multiple independent LED strings (white LED string, RGB LED strings) that are spatially separated by light-blocking walls. Each string is mounted on separate regions of the PCB/FPC, preventing optical cross-talk while maintaining manufacturing simplicity through modular assembly procedures.
Solution Approach 2:
Light-blocking walls are introduced as intermediary structures between adjacent LED strings. These walls act as optical barriers that prevent light from one LED string from interfering with adjacent strings, thereby maintaining color saturation and gamut area while allowing close proximity mounting for compact design.
2Area of stationary object
If multiple LED strings are arranged closely together, then the filament width is reduced and compactness is improved, but optical cross-talk between strings increases causing color distortion
Solution Approach 1:
The solution adds a vertical dimension to the structure by introducing light-blocking walls that extend upward from the PCB/FPC surface. This three-dimensional arrangement allows horizontal compactness (small filament width) while maintaining vertical optical isolation between LED strings, preventing cross-talk without increasing planar footprint.
Solution Approach 2:
Light-blocking properties are applied locally at critical interfaces between LED strings rather than uniformly across the entire filament. The light-blocking walls are positioned specifically where optical cross-talk would occur, providing targeted isolation while allowing light emission in desired directions, thus maintaining compact dimensions without compromising color quality.
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 effectively reduces or prevents optical cross-talk, maintaining a larger color-gamut area and achieving saturated color points, thereby enhancing the color tunability of LED filament lamps.
Implementation Method 1
at least one light-blocking wall arranged between the first LED filament portion and the second LED filament portion to reduce or prevent optical cross-talk between the first LEDs of the first LED filament portion and the second LEDs of the second LED filament portion
Data Source
AI summary
The present invention relates to an LED filament (10), comprising: a first LED filament portion (12a) comprising a plurality of first LEDs (14a) adapted to emit first LED filament light: a second LED filament portion (12b) parallel to the first LED filament portion (12a) and comprising a plurality of second LEDs (14b) adapted to emit second LED filament light: and at least one light-blocking wall (26) arranged between the first and second LED filament portions to reduce or prevent optical cross-talk between the first and second LEDs.