Patterned Adhesive Member for LCD Light Leakage Reduction
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Solution Overview
Problem
Liquid crystal displays experience light leakage due to adhesive materials located between the light guide plate and the flexible printed circuit board (FPCB) with mounted LEDs, as light emitted from the LEDs can pass through these adhesives, causing unwanted light exit at adhesive regions.
Innovation Solution
A double-sided adhesive member is strategically placed between the LEDs on the FPCB, avoiding continuous contact along high-intensity light pathways to minimize light leakage, while still ensuring strong adhesion between the FPCB, main support, and light guide, using pre-patterned tapes or curable fluid adhesives with specific shapes like quadrangular, triangular, or circular configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a continuous adhesive member is used to affix the FPCB, main support, and light guide together, then adhesion strength is improved, but light leakage occurs along the adhesive pathways
Solution Approach 1:
The adhesive member is divided into multiple discrete adhesive regions separated by non-adhesive gaps. These gaps are strategically positioned to interrupt continuous light pathways from LEDs while adhesive regions maintain structural bonding between FPCB, main support, and light guide, thus resolving the contradiction between adhesion strength and light leakage prevention
Solution Approach 2:
Different regions of the adhesive member have different properties: adhesive regions provide strong bonding while non-adhesive gap regions block light transmission. This local differentiation allows the same component to simultaneously satisfy both adhesion requirements and light leakage prevention requirements in different spatial locations
2Strength
If adhesive material is placed between the light guide plate and FPCB, then structural adhesion is improved, but incident light efficiency decreases due to light absorption and scattering
Solution Approach 1:
The adhesive member is segmented into discrete regions with gaps between them, reducing the total adhesive material in light pathways. This segmentation maintains necessary structural adhesion while minimizing light absorption and scattering, thereby improving incident light efficiency
Solution Approach 2:
Adhesive material is extracted from continuous pathways and retained only in specific discrete regions. This removal of excess adhesive from light transmission areas reduces parasitic light absorption and scattering while preserving adhesion function where structurally necessary
3Manufacturing precision
If multiple separate adhesive components are used to affix different parts, then adhesion precision is improved, but device complexity increases
Solution Approach 1:
Multiple adhesive functions are merged into a single integrated adhesive member with patterned adhesive and non-adhesive regions. This unified component simultaneously provides adhesion between FPCB, main support, and light guide while the patterned design ensures precise light pathway interruption, reducing assembly complexity compared to multiple separate adhesive components
4Reliability
If adhesive member covers the entire surface of FPCB, then bonding reliability is improved, but light leakage occurs through adhesive pathways
Solution Approach 1:
The adhesive member is segmented into discrete adhesive regions separated by non-adhesive gaps. This segmentation maintains bonding reliability at adhesive interfaces while the gaps strategically interrupt continuous light pathways from LEDs, preventing light leakage through adhesive material
Solution Approach 2:
Non-adhesive gaps act as intermediary elements between adhesive regions. These gaps serve dual functions: maintaining structural integrity through adhesive regions while blocking light transmission pathways, thus mediating between bonding reliability requirements and light leakage prevention requirements
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 configuration significantly reduces light leakage and enhances manufacturing simplicity by maintaining adhesion without continuous light conducting pathways, improving incident light efficiency and color coordinate consistency by about 20% compared to traditional methods.
Implementation Method 1
a double-sided adhesive member formed to affix together the FPCB, the main support, and the light guide
Data Source
AI summary
The high intensity light output of edge lighting point light sources such as LEDs may generate undesired leakage light that is optically conducted by way of a continuum of the material of a components affixing adhesive member. In accordance with present disclosure, air filled grooves or other such discontinuities are formed in the adhesive member along respective light output pathways of the respective point light sources. One corresponding embodiment comprises spaced apart LEDs mounted on an FPCB; a light guide plate (LGP) disposed adjacent to the LEDs; a main support accommodating the LEDs and the LGP; and an adhesive member formed to affix together the FPCB, the main support, and the light guide, wherein the adhesive member is patterned to define air filled grooves along respective light output pathways of the LEDs.