Backlight Unit Driving Current Correction Circuit
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Solution Overview
Problem
Existing backlight units for LCD devices face issues with fluctuating driving currents due to deviations in resistor levels, leading to defective units and inefficient rework processes that are time-consuming and labor-intensive.
Innovation Solution
A backlight unit with a static current switching element, sensing resistor, and a driving current corrector that detects and automatically corrects the driving current in real-time by generating a control signal based on sensing voltage comparisons with upper and lower limit reference voltages, using a control signal generator, comparators, and switching elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual soldering process is used to correct resistor levels in defective backlight units, then resistor level correction can be achieved, but operation time is relatively long and labor cost increases
Solution Approach 1:
The backlight unit performs self-diagnosis and self-correction through the driving current corrector that automatically detects driving current levels and adjusts resistor values without external intervention, eliminating manual soldering operations
Solution Approach 2:
The patent replaces manual mechanical soldering with an automated electronic control system comprising comparators, switching elements, and a driving current corrector that electronically adjusts resistor levels based on feedback signals
2Manufacturing precision
If manual soldering process is used to correct resistor levels, then resistor level correction can be achieved, but the process is labor-intensive and requires operator intervention
Solution Approach 1:
The system automatically detects driving current deviations and corrects resistor levels through the driving current corrector without requiring operator intervention, achieving full automation of the correction process
Solution Approach 2:
The patent implements a feedback mechanism where the sensing resistor monitors driving current levels, comparators compare actual levels against target levels, and the driving current corrector automatically adjusts resistor values based on this feedback information
3Device complexity
If resistor levels deviate from target levels, then driving current control can be simplified, but driving current fluctuation increases and defect rate increases
Solution Approach 1:
The patent employs feedback control where sensing resistors continuously monitor driving current levels, comparators compare these levels against predetermined target levels, and driving current correctors automatically adjust resistor values to maintain stable driving current despite initial component variations
Solution Approach 2:
The system dynamically changes resistor level parameters through the driving current corrector based on real-time feedback, allowing the system to adapt to component tolerances and maintain optimal driving current levels
4Manufacturing precision
If rework is performed on backlight units with driving current deviations, then driving current can be corrected, but the correction process is difficult and time-consuming
Solution Approach 1:
The backlight unit automatically corrects its own driving current issues through the integrated driving current corrector, eliminating the need for external rework operations and making the correction process trivial
Solution Approach 2:
The patent replaces difficult manual soldering and rework operations with automated electronic control that adjusts resistor levels through switching elements and control circuits, making correction as simple as applying power to the unit
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 solution stabilizes the driving current within a tolerance range, reducing fluctuations and eliminating the need for lengthy rework processes, thereby saving labor and time while ensuring accurate resistor adjustments.
Implementation Method 1
a sensing resistor (Rs) connected between the sensing node and a ground
Data Source
AI summary
A backlight unit capable of substantially reducing a change in a level of a driving current includes: a light source; a static current switching element connected between the light source and a sensing node and controlling a driving current supplied to the light source; a sensing resistor connected between the sensing node and a ground; a static current controller controlling an operation of the static current switching element based on a sensing voltage from the sensing node and an externally supplied driving current control signal; and a driving current corrector generating the driving current control signal and correcting a level of the driving current control signal based on the sensing voltage.