LED Backlight Current Regulation for Display Uniformity
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Solution Overview
Problem
Existing display apparatuses using non-self-emission type liquid crystal displays face challenges in maintaining consistent light quantity due to fluctuations in forward voltages of light-emitting diodes, leading to increased labor and costs in resistance value measurement and selection.
Innovation Solution
The display apparatus employs N light-emitting diode strings connected in parallel, with a current regulator and drive unit configuration that includes a reference voltage generating circuit, differential amplifier circuits, and field-effect transistors to regulate current flow evenly across the strings, preventing variations in light quantity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If resistance values of light-emitting diodes are measured and selected manually, then light quantity consistency can be improved, but labor and costs increase
Solution Approach 1:
The system uses automatic circuit configuration where the control unit autonomously identifies and connects light-emitting diodes with similar forward voltage characteristics. The circuit automatically balances current distribution across parallel strings without manual intervention, achieving light quantity consistency through self-regulating mechanisms.
Solution Approach 2:
The invention changes the selection parameter from manual resistance measurement to automated forward voltage characteristic matching. By using circuit configuration that automatically identifies and groups light-emitting diodes based on their electrical characteristics, the system achieves consistent light output without manual sorting operations.
2Illumination intensity
If multiple light-emitting diodes are connected in parallel to increase brightness, then illumination intensity improves, but current distribution uniformity deteriorates
Solution Approach 1:
The system divides the parallel light-emitting diode connections into multiple strings with controlled configurations. By segmenting the parallel arrangement and using controlled coupling between strings, the circuit maintains uniform current distribution while achieving high illumination intensity through coordinated operation of multiple segments.
Solution Approach 2:
The control unit continuously monitors the electrical characteristics of light-emitting diode strings and adjusts current distribution in real-time. This feedback mechanism ensures uniform current flow across all parallel strings, preventing hot spots and maintaining consistent brightness while supporting high overall illumination intensity.
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 configuration effectively reduces variations in light quantity without increasing labor or costs, while simplifying the drive unit configuration and enhancing withstand voltage, allowing for consistent illumination across the display panel.
Implementation Method 1
N light-emitting diode strings connected in parallel with each other, each of the N light-emitting diode strings includes M light-emitting diodes connected in series
Implementation Method 2
a current regulator configured to regulate current flowing in each of the N light-emitting diode strings
Data Source
AI summary
The instant application describes a display apparatus that includes a display panel configured to display an image; and a backlight unit configured to illuminate the display panel from a back of the display panel. The backlight unit includes: N light-emitting diode strings connected in parallel with each other, each of the N light-emitting diode strings includes M light-emitting diodes connected in series, N being an integer of 2 or more and M being an integer of 1 or more; a power source unit connected in series with the N light-emitting diode strings and configured to generate a voltage; a drive unit connected in series with the N light-emitting diode strings and the power source unit and configured to supply currents to the N light-emitting diode strings; and a current regulator configured to regulate current flowing in each of the N light-emitting diode strings.