LED Color Mixing via Time-Division Multiplexing on Rectified AC
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Solution Overview
Problem
Existing LED lighting systems for aircraft interiors face challenges in efficiently implementing color mixing functionality with a minimal number of components, particularly when operating on rectified AC voltage without the need for a switched-mode power supply.
Innovation Solution
An LED lighting device with a color mixing unit comprising multiple color groups of LEDs, controlled by a device that selectively activates and deactivates these groups to generate a mixed color, utilizing a rectified AC voltage supply, and employing time-division multiplexing to achieve color mixing with minimal components and avoid flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switched-mode power supply is used to operate LEDs with AC voltage, then the LEDs can be operated reliably, but the device complexity and component count increase significantly
Solution Approach 1:
The patent extracts and removes the switched-mode power supply from the system, replacing it with a direct connection to the rectified AC voltage. The LED arrangement is designed to operate directly from the rectified AC voltage without requiring complex power conversion circuitry, thereby eliminating the switched-mode power supply and its associated components while maintaining reliable LED operation.
Solution Approach 2:
The LED arrangement is designed to serve multiple functions: it acts as both the lighting source and the voltage regulation mechanism. By configuring LEDs in different series/parallel arrangements, the system can adapt to different AC voltage levels and maintain reliable operation without requiring a dedicated power supply circuit, thus achieving multi-functionality with minimal components.
2Illumination intensity
If multiple color groups of LEDs are activated simultaneously to achieve color mixing, then the color mixing quality improves, but the risk of flickering increases due to AC voltage variations
Solution Approach 1:
The patent employs periodic activation of color groups synchronized with the AC voltage cycle. Instead of simultaneous activation, color groups are activated in periodic sequences that align with the rectified AC voltage waveform. This periodic action ensures that each color group receives adequate voltage during its activation period while maintaining overall color mixing quality and preventing flickering through proper timing synchronization.
Solution Approach 2:
The system dynamically adjusts the activation timing and duration of different color groups based on the instantaneous AC voltage level. The control mechanism modifies which color groups are active at different points in the AC cycle, optimizing color mixing while ensuring stable operation. This dynamic adaptation allows the system to maintain high illumination quality without flickering by responding to voltage variations in real-time.
3Adaptability or versatility
If the LED arrangement is configured to accommodate varying AC voltage levels, then the adaptability to different power supplies improves, but the device complexity increases
Solution Approach 1:
The LED arrangement is segmented into multiple color groups with different series/parallel configurations. Each segment is designed to operate within specific voltage ranges, and the system switches between segments based on the input AC voltage level. This segmentation allows the system to adapt to different voltage levels (e.g., 100-130V or 200-260V AC) without requiring complex voltage regulation circuitry, as each segment is optimized for its voltage range.
Solution Approach 2:
The patent changes the electrical parameters (series/parallel connections) of LED groups based on the detected AC voltage level. When high voltage is detected, certain groups are connected in series to accommodate the higher voltage; when low voltage is detected, the same groups are reconfigured in parallel. This parameter change approach provides voltage adaptability while maintaining a relatively simple physical structure, avoiding the need for complex power supply equipment.
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 enables efficient color mixing in aircraft interiors with a reduced component count, ensuring stable and flicker-free lighting by synchronizing the activation of color groups with the AC voltage supply, effectively addressing the need for efficient and cost-effective color mixing in LED lighting systems.
Implementation Method 1
The color mixing unit (7) comprises a plurality of LEDs (light-emitting diodes) arranged in any desired distribution on a surface, with LEDs differing in luminous color depending on the color group
Implementation Method 2
the color groups being controlled within a color time window (F) in such a way that they are activated one after the other in order to generate the mixed color during the color time window
Implementation Method 3
The voltage supply (13) can include a rectifier device, which rectifies the AC voltage of the AC voltage supply (2) into the rectified AC voltage as the supply voltage with a supply current
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
LED lighting has the advantage over thermal light sources of being very small and commercially available in various colors, making it possible to produce colored lighting cost-effectively and with minimal installation space. The object of the present invention is to equip an LED lighting device with a color mixing functionality characterized by high efficiency and a small number of components. For this purpose, an LED lighting device 1 is equipped with a color mixing unit 7, wherein the color mixing unit 7 comprises at least a first and a second color group 9a, b, c of LEDs, the LEDs of color groups 9a, b, c being distinguished by their luminous color R, B, G, respectively, and a power supply 5 for supplying the color mixing unit with a supply voltage 13, wherein the supply voltage 13 is in the form of a rectified alternating voltage.wherein a repetition frequency of half-waves H1, H2, H3 of the supply voltage defines a voltage frequency, and with a control device 8 for selectively activating and deactivating the color groups 9 a, b, c, wherein the color mixing unit 7 generates a mixed color M1, M2, M3 through the selectively activated and deactivated color groups 9 a, b, c, proposed, wherein a repetition frequency of a color time window F defines a color mixing frequency, wherein the control device 8 is configured to control the color groups 9a, b, c such that they are activated successively within the color time window F in order to generate the mixed color M1, M2, M3 during the color time window F.