Fluorescent Lamp Array Inverter Voltage Control
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Solution Overview
Problem
As the size of liquid crystal display backlights increases, fluorescent lamp arrays exhibit a noticeable difference in light output at opposite ends due to manufacturing variations and changes in component values with temperature, leading to uneven brightness, which existing solutions attempt to correct manually or through inverter voltage adjustments, but these methods are prone to human error and require additional labor and adjustments over time.
Innovation Solution
An electrical circuit comprising a microcontroller and firmware that generates pulse-width modulated inverter switch control signals with variable duty cycles to adjust inverter voltages automatically, ensuring equal light output at both ends of the fluorescent lamp array by using sensors to measure parameters and feedback signals to calculate and adjust the duty cycles of the inverter bridges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the length of fluorescent lamps is increased to accommodate larger display width, then the display size is improved, but the difference in light output at opposite ends becomes noticeable
Solution Approach 1:
The patent applies local quality by adjusting the inverter voltage independently at each end of the fluorescent lamp array. The system measures light output at both ends and applies different voltage corrections to each end, allowing each region to have optimized illumination characteristics rather than treating the entire array uniformly.
Solution Approach 2:
The patent changes the inverter voltage parameter to compensate for light output differences. By varying the inverter voltage applied to each end of the fluorescent lamp array, the system adjusts the electrical parameters to achieve uniform light output across the entire display area.
2Illumination intensity
If manual adjustment methods are used to correct light output differences, then the light output can be balanced, but human error and additional labor are introduced
Solution Approach 1:
The system performs self-service by automatically measuring light output at both ends of the fluorescent lamp array and adjusting the inverter voltage without human intervention. The microcontroller continuously monitors the light output and autonomously makes corrections, eliminating the need for manual adjustment and reducing human error.
Solution Approach 2:
The patent implements feedback control by measuring the light output at each end of the fluorescent lamp array and using this information to adjust the inverter voltage. The system continuously monitors the light output and makes real-time corrections to maintain uniform illumination, creating a closed-loop control system.
3Illumination intensity
If inverter voltage adjustments are made to correct light output differences, then brightness uniformity is improved, but component mismatches and temperature changes require continuous adjustments
Solution Approach 1:
The patent uses continuous feedback control to monitor light output and adjust inverter voltage in response to changing conditions. By continuously measuring light output at both ends and making real-time adjustments, the system compensates for component mismatches and temperature changes, maintaining stable and reliable operation without requiring manual re-adjustment.
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
Automatically adjusts the inverter voltages to maintain equal light output at both ends of the fluorescent lamp array, reducing human error and labor costs, and continuously compensating for component mismatches and temperature changes, ensuring consistent brightness across the display.
Implementation Method 1
generating a pulse-width modulated inverter switch control signal having a duty cycle that may be varied to adjust the inverter voltage
Data Source
AI summary
A method and electrical circuit corrects a difference in light output at opposite ends of a fluorescent lamp array. An electrical circuit for correcting a difference in light output at the ends of a fluorescent lamp array includes a microcontroller and firmware for generating a first pulse-width modulated inverter switch control signal having a first duty cycle that may be varied by computer program instructions executed by the microcontroller. An inverter bridge driver is coupled to the microcontroller for generating a switching signal for a first inverter bridge from the first pulse-width modulated inverter switch control signal to generate a first inverter voltage having a magnitude determined by the first duty cycle.