Segmented Adhesive Fixing Light Guide Plate Thermal Expansion
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Solution Overview
Problem
The existing backlight modules in LCD devices face a reduction in brightness due to high-temperature operation, caused by poor heat dissipation, leading to expansion and contraction issues with the light guide plate (LGP) that result in decreased light extraction efficiency and display brightness.
Innovation Solution
The use of segmented double-sided adhesive tapes to fix the LGP, allowing for greater expansion along the length direction of the light source while minimizing expansion in the width direction, reducing the gap between the LGP and the light source, and utilizing transparent adhesive layers with patterned structures to enhance light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional double-sided adhesive tapes are used to fix the LGP to the backplate, then the LGP can be securely fixed, but the LGP cannot accommodate thermal expansion and contraction during high-temperature operation, causing gaps between the LGP and light source
Solution Approach 1:
The adhesive tape is divided into multiple segments along the length direction, with each segment independently adhering to the LGP at different positions. This segmentation allows each adhesive segment to independently accommodate local thermal expansion and contraction of the LGP, preventing gap formation while maintaining overall fixing stability during temperature fluctuations
Solution Approach 2:
The adhesive tape transitions from a static, rigid fixing structure to a dynamic structure that can adapt to thermal changes. The segmented design enables the adhesive tape to dynamically adjust its configuration during thermal expansion and contraction cycles, maintaining optimal contact between the LGP and light source across varying temperature conditions
2Manufacturing precision
If the LGP is tightly fixed to prevent movement, then positioning precision is improved, but light extraction efficiency decreases due to gaps formed during thermal contraction
Solution Approach 1:
By segmenting the adhesive tape into multiple independent sections, the LGP can maintain precise positioning through collective adhesion while allowing localized movement at each segment interface. This enables the LGP to remain tightly positioned during normal operation but accommodate thermal contraction without forming gaps that would reduce light extraction efficiency
3Strength
If continuous adhesive tape is used to ensure complete coverage, then fixing strength is improved, but light extraction efficiency is reduced due to excessive adhesive material between the LGP and light source
Solution Approach 1:
The adhesive tape is segmented into discrete sections rather than forming a continuous layer. This segmentation maintains adequate fixing strength through distributed adhesion points while creating gaps between segments that allow light to pass through, thereby improving light extraction efficiency by reducing the total adhesive material between the LGP and light source
Solution Approach 2:
Different regions of the adhesive structure serve different functions: adhesive segments provide fixing strength at specific locations, while the spaces between segments allow light transmission. This local differentiation of function enables simultaneous achievement of strong fixation and high light extraction efficiency
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 solution maintains high display brightness by minimizing the gap between the LGP and the light source during temperature fluctuations, improving light extraction efficiency and reducing residual adhesive issues for reusable components.
Implementation Method 1
an end of the light guide plate which is close to the light source is fixed on the flexible printed circuit board and/or the backplate through segmented double-sided adhesive tapes
Implementation Method 2
utilizing transparent adhesive layers with patterned structures to enhance light extraction efficiency
Implementation Method 3
the end of the LGP 3 close to the LEDs is expanded quite severely, causing the LGP 3 to extend further away from the LEDs
Data Source
AI summary
A display backlight module includes a light guide plate, a light source disposed on a side of the light guide plate, and at least one of a flexible printed circuit board and a backplate, such that an end of the light guide plate closest to the light source is fixed on the flexible printed circuit board or the backplate by a plurality of double-sided adhesive blocks spaced apart from each other.