LED Backlight Driver COF Package Thermal Isolation
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Solution Overview
Problem
Conventional LED backlight drivers in display apparatuses face issues with heat management, leading to reduced reliability and color cast problems due to direct contact between driving chips and the backlight module, which limits the number of local dimming zones and affects the service life of LEDs.
Innovation Solution
Implementing a chip-on-film (COF) package for the driving chip, which is not in direct contact with the backlight module, allowing for reduced heat transfer and improved heat dissipation, thereby enhancing the reliability of the backlight module and alleviating color cast issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If LED driving chips are soldered directly to the backlight module in conventional wire bonding package manner, then the device structure is simple and easy to manufacture, but the driving chips cannot efficiently release heat causing overheating and color cast problems
Solution Approach 1:
The patent introduces a flexible circuit board as an intermediary carrier between the LED driving chip and the backlight module. The chip is mounted on the flexible circuit board using COF package technology, which separates the heat-generating chip from the heat-sensitive backlight module while maintaining electrical connection through the flexible circuit board's conductive traces.
Solution Approach 2:
The patent extracts the LED driving chip from direct contact with the backlight module by mounting it on a separate flexible circuit board. This extraction removes the heat source from the immediate vicinity of the backlight module, preventing thermal interference while maintaining the functional relationship through the flexible circuit board connection.
2Volume of moving object
If LED driving chips are mounted directly on the backlight module, then the device size is compact, but the service life of LEDs is shortened due to heat-related degradation
Solution Approach 1:
The flexible circuit board serves as a mediator that maintains close proximity between the driving chip and backlight module for compactness while simultaneously providing thermal isolation to protect LED service life from heat degradation.
Solution Approach 2:
The patent employs a flexible circuit board - a thin film structure - to mount the driving chip near the backlight module without direct contact. This flexible film enables compact integration while its inherent flexibility and thin profile allow for effective thermal management by preventing heat transfer to the LEDs.
3Productivity
If the number of backlight local dimming zones is increased, then the display performance is improved, but the control PCB becomes bulky and reaches maximum size limits
Solution Approach 1:
The patent transitions from a rigid two-dimensional PCB layout to a flexible three-dimensional configuration using flexible circuit boards. This allows the driving chips to be arranged in multiple layers and orientations, enabling increased number of local dimming zones without proportionally increasing the footprint area of the control PCB.
Solution Approach 2:
The flexible circuit board serves multiple functions: it acts as a mechanical support structure, an electrical connection medium, and a space-efficient mounting platform. This multi-functionality allows the control PCB to accommodate more driving chips for increased local dimming zones while maintaining a compact form factor.
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 COF package configuration reduces heat-related issues, increases the number of backlight dimming zones, and extends the service life of LEDs by preventing overheating, thus improving the overall reliability and performance of the backlight module.
Implementation Method 1
the at least one driving chip is disposed on at least one chip-on-film (COF) package, and not in direct contact with the backlight module to reduce heat transfer to the backlight module
Data Source
AI summary
An LED backlight driver includes at least one driving chip configured to drive a backlight module. The at least one driving chip is disposed on at least one chip-on-film package, and not in direct contact with the backlight module to reduce heat transfer to the backlight module.