LED Module Current Control for Consistent Color Gamut
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Solution Overview
Problem
Existing LED modules face challenges in maintaining a consistent gamut due to variations in the emission properties, particularly center wavelengths, of individual LEDs, which affect the color reproduction capabilities.
Innovation Solution
A method and LED module design that adjusts the current strength for each LED to compensate for manufacturing variations, using pulse-width modulation (PWM) to adjust center wavelengths and achieve a predetermined gamut through additive color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If LEDs are operated at high current densities to increase luminous intensity, then illumination intensity is improved, but light output decreases non-linearly over time due to degradation
Solution Approach 1:
The patent implements dynamic current adjustment by controlling the LED driver to vary drive current based on operational phase. During initial operation, higher currents are applied to achieve desired luminous intensity, then currents are reduced to extend lifespan and maintain stability, resolving the contradiction between initial brightness and long-term reliability
Solution Approach 2:
The patent employs periodic dimming cycles where the LED operates at full intensity for a initial period, then transitions to reduced intensity periods. This periodic operation pattern allows the LED to achieve high luminous intensity when needed while spending more time at lower currents to prevent degradation, thereby maintaining light output stability over time
2Illumination intensity
If LEDs are operated at high current densities to increase luminous intensity, then illumination intensity is improved, but operational lifetime decreases
Solution Approach 1:
The patent applies preliminary action by implementing a controlled initial operation phase where LEDs are driven at high currents to achieve required luminous intensity, followed by a transition to reduced current operation. This preliminary high-intensity phase is time-limited and followed by maintenance phases that extend operational lifetime, effectively managing the trade-off between initial performance and long-term durability
Solution Approach 2:
The system dynamically adjusts drive current based on operational phase and monitored LED performance. By continuously adapting the current level rather than maintaining a fixed high current, the system achieves high luminous intensity when required while minimizing the cumulative stress that reduces operational lifetime
3Illumination intensity
If LEDs are operated at high current densities to increase luminous intensity, then illumination intensity is improved, but color temperature shifts occur
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor LED output characteristics including color temperature. When LEDs are driven at high currents causing color shifts, the system detects these changes and adjusts operating parameters to compensate, thereby maintaining color temperature consistency while still achieving required luminous intensity through controlled operation
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating an LED module (1), wherein the LED module (1) comprises at least three varicoloured LEDs (2, 3, 4) which collectively span a gamut of adjustable colour points and which are controlled by means of a driver device (5) via control signals (6), wherein current strengths, with which the at least three varicoloured LEDs (2, 3, 4) are each operated, are adjusted to set predefined corner points of the gamut, such that a predefined gamut is provided. The invention also relates to an LED module (1).