LED Wavelength Shift Compensation via Dual Electrical Biasing
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Solution Overview
Problem
Existing methods for controlling the intensity of light emissions from LEDs, such as PWM and CCR, result in wavelength shifting and color distortions, which are unacceptable for many applications and have not been effectively addressed, often requiring complex and costly feedback systems to compensate for these issues.
Innovation Solution
A method and apparatus that utilize a combination of electrical biasing techniques, such as superposition or alternation of PWM and CCR, to maintain a stable perceived color emission across a range of intensities and temperatures without significant resistive impedances, thereby minimizing power losses and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If PWM or CCR methods are used to control LED intensity, then intensity regulation is achieved, but wavelength shifting and color distortions occur
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting multiple electrical parameters (current, voltage, duty cycle) in combination to compensate for wavelength shifts. The controller modifies at least one of current, voltage, or duty cycle based on detected wavelength changes, transforming the control approach from single-parameter to multi-parameter adjustment to maintain stable color emission across intensity ranges.
Solution Approach 2:
The patent implements feedback by using a wavelength detector to monitor the actual wavelength emitted by the LED and feeding this information back to the controller. The controller then adjusts the electrical parameters accordingly to counteract wavelength shifts, creating a closed-loop control system that actively compensates for color distortions during intensity regulation.
2Stability of the object's composition
If complex feedback systems are used to compensate for wavelength shifting, then color stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by designing a controller that performs multiple functions: it regulates intensity, compensates for wavelength shifts, and adjusts electrical parameters dynamically. This multi-functional approach consolidates what would traditionally require separate dedicated circuits for wavelength compensation into a single integrated control unit, reducing overall system complexity while maintaining color stability.
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 stable color emission with reduced power losses and increased efficiency, allowing for longer battery life in portable devices and simpler, cost-effective implementation, while maintaining the intensity and color stability of LED lighting systems.
Implementation Method 1
Because a light-emitting diode is a semiconductor device that emits incoherent, narrow-spectrum light when electrically biased in the forward direction of its (p-n) junction
Data Source
AI summary
Representative embodiments of the disclosure provide a system and apparatus for controlling an intensity and spectrum of light emitted from a solid state lighting system. The solid state lighting system has a first emitted spectrum at full intensity and at a selected temperature, with a first electrical biasing for the solid state lighting system producing a first wavelength shift, and a second electrical biasing for the solid state lighting system producing a second, opposing wavelength shift. Representative embodiments provide for receiving information designating a selected intensity level and a selected temperature and providing a combined first electrical biasing and second electrical biasing to the solid state lighting system to generate emitted light having the selected intensity level and having a second emitted spectrum within a predetermined variance of the first emitted spectrum over a predetermined range of temperatures.