Backlight Device Time Division Drive Circuit
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Solution Overview
Problem
Existing liquid crystal display devices face challenges with increased circuit sizes and heating values due to the need for dedicated control chains and constant current sources for each divided area in the backlight, especially as the number of divided areas increases, leading to inefficiencies in area light modulation and scanning backlight functions.
Innovation Solution
A backlight device with a plurality of divided areas where light sources are chain-connected, and a control part that uses time division to select and drive these areas using shared backlight drive paths, reducing the number of control parts and drive paths required, thereby minimizing circuit sizes and heating values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dedicated control chains and constant current sources are provided for each divided area in the backlight, then area light modulation function is achieved, but circuit size and heating value increase
Solution Approach 1:
Multiple LED chains that were previously controlled by separate control circuits are merged into a single control circuit. The control circuit sequentially selects and controls different LED chains through switching mechanisms, allowing one circuit to perform the function of multiple dedicated circuits, thereby reducing overall circuit size while maintaining area light modulation capability
Solution Approach 2:
The control circuit employs periodic sequential scanning to control different divided areas of the backlight. By cyclically selecting and controlling LED chains in sequence rather than simultaneously, the system achieves area light modulation with a single control circuit, reducing circuit complexity and heating value while maintaining functional versatility
2Adaptability or versatility
If dedicated control chains and constant current sources are provided for each divided area in the backlight, then area light modulation function is achieved, but heating value increases
Solution Approach 1:
Multiple constant current sources that were previously required for each divided area are merged into a single constant current source. This single source sequentially provides current to different LED chains through switching mechanisms, reducing the total number of power supply circuits and thereby decreasing heating value while maintaining the ability to control different backlight areas
Solution Approach 2:
The single constant current source operates periodically by sequentially supplying current to different LED chains in sequence. This time-division multiplexing approach allows one constant current source to replace multiple dedicated sources, significantly reducing the heating value generated by power supply circuits while preserving area light modulation functionality
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 approach reduces the circuit sizes and heating values for area light modulation and scanning backlight functions, allowing for more efficient and cost-effective implementation while maintaining image quality and reducing power consumption.
Implementation Method 1
a light emitting diode (LED) instead of the CCFL is also used as the light source for the backlight
Data Source
AI summary
The backlight device includes: a backlight including a plurality of light sources; and a backlight control part. The backlight includes a plurality of divided areas, and light sources disposed in each of the plurality of divided areas are chain-connected. The backlight control part includes at least one backlight control unit for controlling turning on and off of the backlight which includes the plurality of divided areas, with respect to the each divided area. The backlight control unit includes a selection unit for selecting one of divided areas, at least one backlight drive path. The selection unit selects the one of divided areas in a time division manner, and the light sources of the one of divided areas are driven by sharing the at least one backlight drive path in common.