LED Illumination Module Current Routing for CCT Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current LED-based illumination devices face limitations in light output level, color quality stability, and expense due to color point instability, poor color rendering, and spatial/angular variations in color, which are exacerbated by the need for complex color control electronics and sensors.
Innovation Solution
The implementation of a modular LED illumination system where LEDs in different zones are selectively illuminated by independently routing current from a single source to different strings, allowing for adjustable Correlated Color Temperature (CCT) through control of switching frequency and duty cycle, thereby enhancing color rendering and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single current source is used to drive multiple LED strings in different zones, then device complexity and cost are reduced, but the ability to independently control flux from each zone is limited
Solution Approach 1:
The LED illumination device is divided into multiple zones with distinct LED strings, where each zone can be independently controlled through a current router that selectively directs current to specific zones based on switching frequency and duty cycle, enabling independent flux control without requiring separate current sources for each zone
Solution Approach 2:
The patent employs dynamic control parameters including switching frequency and duty cycle to enable a single current source to adaptively control multiple LED strings. By varying these parameters, the system can independently adjust the flux output of different LED zones, transforming a static single-source limitation into a dynamic multi-zone control capability
2Stability of the object's composition
If LEDs with different color characteristics are used in different zones, then color quality and CCT adjustability are improved, but manufacturing precision and color matching become more difficult
Solution Approach 1:
Different zones of the LED illumination device incorporate LEDs with specific color characteristics tailored to their function. For example, certain zones use LEDs optimized for specific wavelength ranges to illuminate different portions of phosphor materials, enabling independent color tuning and improved overall color quality without requiring precise color matching across all LEDs
Solution Approach 2:
The patent utilizes variations in LED operational parameters such as forward voltage, current, and switching frequency to achieve color point stability. By controlling the electrical parameters of LEDs in different zones, the system can maintain consistent color output despite manufacturing variations, reducing the need for tight color matching during assembly
3Stability of the object's composition
If complex color control electronics and sensors are used to maintain color point, then color quality is improved, but device complexity and cost increase
Solution Approach 1:
The LED illumination device achieves color point stability through self-regulating mechanisms where the physical layout of LEDs in different zones, combined with phosphor materials of varying properties, creates inherent color balance. The system uses the natural optical interactions between LED emissions and phosphor conversion rather than active feedback control, eliminating the need for color sensors and complex control electronics
Solution Approach 2:
The patent employs phosphor materials with different color conversion characteristics in different zones to achieve desired color output. By strategically placing phosphors with specific emission spectra and using LEDs that excite these phosphors effectively, the system achieves color quality improvement through material selection rather than electronic control
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
This approach enables flexible control of CCT over a broad range, improving color quality and reducing the need for complex electronics, while maintaining efficient light output and minimizing spatial/angular color variations.
Implementation Method 1
An LED based illumination device includes a first LED string comprising a first plurality of LEDs coupled in series, wherein a current supplied to the first LED string causes a light emission from the LED based illumination device with a first Correlated Color Temperature (CCT)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An illumination module includes a plurality of Light Emitting Diodes (LEDs) located in different zones to preferentially illuminate different color converting surfaces. The flux emitted from LEDs located in different zones may be independently controlled by selectively routing current from a single current source to different strings of LEDs in the different zones. In this manner, changes in the CCT of light emitted from LED based illumination module may be achieved.