Backlight Light Source Layout for Slim Thickness and Heat Dissipation
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Solution Overview
Problem
Existing backlight units face challenges in achieving a slim structure while maintaining high efficiency and effective heat dissipation due to limitations in packaging of light emitting diodes, which hinder the use of highly efficient light emitting diode chips.
Innovation Solution
A backlight unit design incorporating a light source with a substrate, semiconductor stack, reflector, and light guide plate, where the reflector reflects light emitted from a first surface towards second surfaces, and a wavelength conversion layer covers the light emitting device to enhance light collection and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a light emitting diode package is mounted on a substrate inside the edge type backlight unit, then thickness reduction is achieved, but heat dissipation deteriorates
Solution Approach 1:
The patent transitions from vertical stacking (mounting LED package on substrate inside backlight unit) to lateral arrangement (mounting LED chip on circuit board side by side). This dimensional change allows heat to dissipate laterally through the circuit board while maintaining slim thickness profile, resolving the contradiction between thickness reduction and heat dissipation performance.
2Length of stationary object
If packaging of light emitting diode is reduced, then thickness reduction is achieved, but high efficiency light emitting diode chip cannot be employed
Solution Approach 1:
The patent extracts the LED chip from the conventional packaged form and mounts it directly on the circuit board in a COB (chip on board) configuration. This extraction eliminates the packaging structure that limited thickness reduction, enabling the use of highly efficient LED chips while achieving slim profile through direct mounting and lateral arrangement.
3Loss of energy
If light emitting diode chip is mounted directly on circuit board, then efficiency is improved, but heat dissipation becomes insufficient
Solution Approach 1:
The patent segments the heat dissipation function by distributing multiple LED chips laterally across the circuit board rather than concentrating them in a single vertical package. This segmentation allows heat to be dissipated across multiple locations and pathways in the circuit board, improving overall heat dissipation capacity while maintaining high luminous efficiency through direct chip mounting.
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 design achieves a slim structure with high output and efficiency, allowing for the use of highly efficient light emitting diode chips by reducing thickness and improving heat dissipation through a COB structure.
Implementation Method 1
a reflector structured and positioned to block light emitted from a first surface of the light emitting device by reflecting the light emitted from the first surface toward second surfaces of the light source
Implementation Method 2
a wavelength conversion layer covering the light emitting device to enhance light collection and efficiency
Data Source
AI summary
A backlight unit includes one or more light sources operable to emit light and a light guide plate arranged adjacent to the one or more light sources, reflected lights exiting the one or more light sources via the second surfaces and entering the light guide plate. A light source includes a light emitting device having a substrate and a semiconductor stack disposed on the substrate. The reflector is structured and positioned to block light emitted from a first surface of the light emitting device by reflecting the light emitted from the first surface toward second surfaces of the light source.