LED Luminance Compensation via Temperature-Dependent Current Regulation
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Solution Overview
Problem
Light-emitting diodes (LEDs) experience a decrease in brightness with increasing temperature, and existing methods for brightness compensation are either inadequate or overly complex, often requiring additional components and increased technical complexity.
Innovation Solution
A method that measures temperature values and uses pre-determined current values stored in a memory module to adjust the current regulator of LEDs, ensuring consistent brightness across temperature fluctuations, without the need for complex digital logic or additional sensors, using analog components to drive LEDs with current values that maintain brightness independently of color settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If existing brightness adjustment methods are used, then LED brightness can be dimmed, but they fail to compensate for temperature-induced brightness decrease
Solution Approach 1:
The patent implements a feedback mechanism by measuring the LED temperature with a temperature sensor and using this measurement to dynamically adjust the drive current through a lookup table that maps temperature values to compensation current values. This closed-loop feedback ensures brightness consistency despite temperature variations.
Solution Approach 2:
The patent changes the drive current parameter based on temperature measurements. By storing pre-calculated compensation current values in a lookup table indexed by temperature, the system dynamically adjusts the current parameter to compensate for temperature-induced brightness changes, maintaining consistent perceived brightness.
2Illumination intensity
If optical sensors are used to measure LED brightness, then brightness can be adjusted to predetermined values, but additional components and complexity are required
Solution Approach 1:
The patent uses temperature as an intermediary parameter instead of directly measuring brightness. By measuring temperature (which is easier and less expensive than optical sensing) and using a pre-stored lookup table to determine the appropriate compensation current, the system achieves brightness control without requiring complex optical sensors or real-time brightness measurements.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing the relationship between temperature and required compensation current in a lookup table during manufacturing or system setup. This pre-computed data allows the runtime system to simply look up the appropriate current value based on measured temperature, avoiding complex real-time calculations or measurements.
3Illumination intensity
If PWM dimming is used, then brightness can be adjusted, but the method is primarily for dimming rather than compensation
Solution Approach 1:
The patent transitions from static PWM dimming to dynamic current adjustment based on real-time temperature measurements. The system dynamically modifies the drive current magnitude (rather than just pulse width) to compensate for temperature effects, providing adaptability to changing thermal conditions while maintaining brightness 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
The method effectively maintains constant brightness perception, reducing the need for additional bits in color settings and minimizing technical complexity, allowing for efficient brightness compensation across temperature changes without visible differences in LED brightness.
Implementation Method 1
A temperature sensor is provided, configured to measure a temperature of the light-emitting diode
Implementation Method 2
A lookup table is provided, configured to store a plurality of current values, each current value having a corresponding temperature value
Implementation Method 3
The current regulator is configured to regulate a current through the light-emitting diode such that a brightness of the light-emitting diode is substantially constant, independent of a temperature of the light-emitting diode
Data Source
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AI summary
The invention is directed to a method for brightness compensation in at least on light emitting diode. The disclosed method achieves a constant brightness of the LED regardless of temperature variations. The invention is also directed to a correspondingly equipped device and to a storage module for use in the disclosed method.