Backlight Unit Chassis and Heat Spreading Layer Design
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Solution Overview
Problem
Conventional backlight assemblies for electronic devices with passive pixels are often bulky, inefficient, and prone to visible artifacts, occupying excessive space and requiring significant design compromises for compactness and performance.
Innovation Solution
A backlight unit with a flexible printed circuit board-mounted row of light-emitting diodes, a light guide layer, and a reflector, combined with a heat spreading layer and adhesive patterns to mitigate wrinkling, and a chassis design that optimizes space usage and light distribution, enhancing backlight efficiency and reducing thermal hotspots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If conventional backlight assemblies are used, then backlight illumination is provided, but the assembly occupies excessive space and is bulky
Solution Approach 1:
The backlight assembly is segmented into distinct functional layers: light guide layer, reflector layer, and heat spreading layer. Each layer performs a specific function and can be independently optimized, allowing the overall assembly to be compact while maintaining performance through specialized layer design
Solution Approach 2:
The patent implements a nested structure where the heat spreading layer is positioned between the light guide layer and the flexible printed circuit board, with the reflector layer attached to the lower surface of the light guide layer. This nested arrangement maximizes space utilization within the limited thickness available in the display assembly
2Reliability
If conventional backlight assemblies are used, then illumination is provided, but visible artifacts occur
Solution Approach 1:
The patent converts potentially harmful thermal effects into beneficial outcomes by implementing the heat spreading layer that redistributes thermal energy from LED hotspots. This prevents thermal-related visible artifacts while the reflected light from the reflector layer compensates for any light loss, turning thermal management into a performance enhancement
Solution Approach 2:
The patent changes the physical and optical parameters of each layer to optimize performance. The light guide layer uses specific refractive index materials, the reflector layer uses high reflectivity coatings, and the heat spreading layer uses materials with specific thermal conductivity properties. These parameter optimizations reduce visible artifacts while maintaining compact dimensions
3Reliability
If conventional backlight assemblies are used, then backlight is provided, but the assembly is not robust
Solution Approach 1:
The patent merges multiple functions into integrated layers that provide both structural support and optical/thermal performance. The light guide layer serves as both an optical element and a structural component, while the heat spreading layer simultaneously manages thermal energy and provides mechanical stability, creating a robust yet compact assembly
Solution Approach 2:
The patent employs composite material structures where each layer is composed of materials with specific properties optimized for its function. The combination of light guide material, reflector material, and heat spreading material creates a composite assembly that is both robust and space-efficient, with each material contributing its unique properties to the overall performance
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 solution provides improved backlight efficiency, reduced bulkiness, and minimized visible artifacts, allowing for more compact and robust electronic device designs with enhanced display performance.
Implementation Method 1
The backlight unit may have a row of light-emitting diodes that are mounted on a flexible printed circuit board and that emit light into a light guide layer
Implementation Method 2
A reflector layer may be attached to a lower surface of the light guide layer
Implementation Method 3
A heat spreading layer may be attached to a lower surface of the reflector layer and a lower surface of the flexible printed circuit board
Data Source
AI summary
A backlight unit may be used to produce backlight illumination for a display. The backlight unit may have a row of light-emitting diodes that are mounted on a flexible printed circuit and that emit light into a light guide layer. The backlight unit may include a chassis that extends around the periphery of the light guide layer. The chassis may have a first portion that is mounted on the flexible printed circuit adjacent to the light-emitting diodes and a second portion that extends over the light-emitting diodes. A heat spreading layer may be attached to a reflector layer and the flexible printed circuit. The heat spreading layer may have a width that is less than the width of the reflector layer. Adhesive patches may attach the light guide layer to the flexible printed circuit. A patterned adhesive layer may be formed over the light-emitting diodes and the light guide layer.