Heat Reactive Adhesive Sheet for LCD Backlight Frame Narrowing
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Solution Overview
Problem
Conventional liquid crystal display devices face challenges in narrowing the frame on the light source side due to insufficient adhesion strength caused by reduced adhesion area between the wiring board and the light guide, leading to non-uniform luminance and peeling issues during drop tests.
Innovation Solution
A light source device with a wiring substrate and a heat reactive adhesive sheet is used, providing enhanced adhesion strength by increasing the adhesive area, allowing for a more compact design and preventing peeling, even with reduced adhesion regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the distance from light sources to display area is reduced and intervals between light sources are reduced, then frame width is narrowed, but adhesion area of double-sided tape is decreased making it difficult to maintain adhesion strength
Solution Approach 1:
The patent changes the adhesive properties by using a heat-reactive adhesive sheet instead of conventional double-sided tape. The adhesive sheet's adhesion characteristics are modified through thermal activation, allowing it to provide sufficient bonding strength even when the adhesion area is reduced due to narrower frame dimensions.
Solution Approach 2:
The patent employs a composite adhesive structure consisting of a heat-reactive adhesive sheet with specific thermal and adhesive properties. This composite material approach allows the adhesive system to compensate for reduced adhesion area by providing enhanced bond strength through thermal activation, resolving the contradiction between narrow frame width and sufficient adhesion strength.
2Length of stationary object
If adhesion area is reduced, then frame can be narrowed, but adhesion between wiring board and light guide becomes incomplete causing non-uniform luminance
Solution Approach 1:
The heat-reactive adhesive sheet modifies its adhesive parameters through thermal activation, creating a more reliable bond between the wiring board and light guide. This ensures complete and uniform adhesion even with reduced adhesion area, preventing the luminance non-uniformity that would otherwise occur due to incomplete bonding.
3Length of stationary object
If adhesion area is reduced, then frame can be narrowed, but double-sided tape peels off during drop test
Solution Approach 1:
The patent transforms the adhesive's performance parameters through thermal activation. The heat-reactive adhesive sheet provides significantly enhanced bond strength and reliability compared to conventional double-sided tape, ensuring the assembly withstands mechanical shocks during drop tests even with reduced adhesion area.
Solution Approach 2:
The patent replaces the mechanical adhesion system (conventional double-sided tape relying solely on physical bonding) with a thermally-activated adhesive system. This substitution allows the adhesive to develop superior bonding characteristics through thermal energy, dramatically improving reliability under mechanical stress conditions.
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 heat reactive adhesive sheet achieves 3 to 5 times the adhesive strength of conventional double-sided tape, enabling a significantly downsized frame on the light source side while maintaining firm attachment, thus addressing non-uniform luminance and peeling issues.
Implementation Method 1
a heat reactive adhesive sheet adhered to the wiring substrate
Data Source
AI summary
According to one embodiment, a light source device includes a wiring substrate including a mount region, a plurality of light sources arranged and mounted on the mount region of the wiring substrate, and a heat reactive adhesive sheet adhered to the wiring substrate.