LED Backlight Unit Without PCB Using Integrated Metal Chassis
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Solution Overview
Problem
Conventional LED backlight units with insulating substrates suffer from high thermal resistance, increased cost, and thickness due to the use of metal core substrates and separate heating pads, leading to reduced light emission, reliability, and lifespan of LED chips.
Innovation Solution
A method of manufacturing an LED backlight unit without a PCB, where an insulating resin layer is applied to a metal chassis, with engraved circuit patterns filled or plated with metal, and LED packages are directly mounted, eliminating the need for a separate PCB and heating pad, thereby reducing thermal resistance and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal core substrates are used for LED mounting, then heat dissipation is improved, but cost increases significantly
Solution Approach 1:
The patent combines the substrate and heating pad functions into a single integrated structure. The metal chassis serves as both the structural support and the heat dissipation path, eliminating the need for separate metal core substrates and heating pads. This merging reduces component count and cost while maintaining effective thermal management through the integrated metal framework.
Solution Approach 2:
The patent extracts the essential heat dissipation function from the expensive metal core substrate and implements it through the metal chassis structure. By separating the structural support function (handled by the chassis) from the heat dissipation function (handled by the metal framework and thermal pathways), the design eliminates the need for costly specialized substrates while maintaining effective thermal management.
2Ease of manufacture
If insulating substrates with heating pads are used, then cost is reduced compared to metal core substrates, but thermal resistance increases and heat dissipation deteriorates
Solution Approach 1:
The patent merges the substrate and heating pad into a single integrated metal chassis structure. This eliminates the thermal interface resistance between separate components by creating direct thermal pathways from the LED chips through the metal framework. The integration maintains low cost while dramatically improving heat dissipation by eliminating the thermal bottleneck of separate insulating layers and heating pads.
Solution Approach 2:
The patent employs composite construction combining metal framework for heat dissipation with localized insulating resin for electrical isolation. This composite approach allows simultaneous achievement of low thermal resistance through the metal pathways and adequate electrical insulation where needed, avoiding the need for expensive full-metal core substrates while maintaining effective thermal management.
3Reliability
If separate PCB and heating pad are used, then electrical connection and thermal management are achieved, but device complexity and thickness increase
Solution Approach 1:
The patent merges the PCB and heating pad into a single integrated metal chassis structure. The metal framework provides both structural support and heat dissipation pathways, while circuit traces are directly formed on or within the chassis. This integration eliminates multiple separate components, reduces assembly steps, and decreases overall thickness while maintaining reliable electrical connections and thermal management.
Solution Approach 2:
The metal chassis serves multiple functions simultaneously: it provides structural support, acts as the heat dissipation pathway, serves as the mounting platform for LED chips, and carries the circuit traces for electrical connections. This multi-functionality eliminates the need for separate specialized components, reducing device complexity and thickness while maintaining all necessary functions.
4Ease of manufacture
If conventional insulating substrates are used, then cost is reduced, but the number of components and assembly steps increase
Solution Approach 1:
The patent combines multiple separate components (substrate, heating pad, mounting structure) into a single integrated metal chassis. This reduction in component count simplifies the manufacturing process, reduces assembly steps, and lowers overall cost while maintaining all necessary functions. The integrated design eliminates interfaces between components, reducing potential failure points and simplifying quality control.
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 significantly reduces thermal resistance and thickness, enhancing the reliability and lifespan of LED chips by efficient heat dissipation and simplifying the manufacturing process while lowering costs.
Implementation Method 1
The chassis 110 is made of material having excellent thermal conductivity, such as metal
Implementation Method 2
forming an insulating resin layer on a chassis made of metal material by applying insulating resin to the chassis in liquid form
Implementation Method 3
filling the engraved circuit patterns with metal material or plating the engraved circuit patterns with metal material
Data Source
Figure 1~2
Figure 3A~3C
Figure 3D~3F
AI summary
Disclosed herein is a Light Emitting Diode (LED) backlight unit without a Printed Circuit board (PCB). The LED backlight unit includes a chassis, insulating resin layer, and one or more light source modules. The insulating resin layer is formed on the chassis. The circuit patterns are formed on the insulating resin layer. The light source modules are mounted on the insulating resin layer and arc electrically connected to the circuit patterns. The insulating resin layer has a thickness of 200 µm or less, and is formed by laminating solid film insulating resin on the chassis or by applying liquid insulating resin to the chassis using a molding method employing spin coating or blade coating. Furthermore, the circuit patterns are formed by filling the engraved circuit patterns of the insulating resin layer with metal material.