Backlight Substrate Using Composite Resist Layers for Delamination Control
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Solution Overview
Problem
Epoxy-based white resist layers used in backlights for liquid crystal display devices degrade over time due to heat and light, leading to decreased reflectance and uneven brightness, while silicone-based alternatives suffer from poor adhesion issues causing delamination of protective layers from circuit substrates.
Innovation Solution
A light-emitting-element-equipped substrate with a silicone-based white resist layer and a non-silicone-based white resist layer, where the non-silicone-based layer enhances adhesion and light reflectance, and is strategically placed between the silicone-based layer and the circuit substrate to prevent delamination and maintain brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an epoxy-based white resist layer is used between the circuit substrate and protective layer, then the initial brightness is maintained, but the brightness decreases and becomes uneven over time due to aging degradation from heat and light
Solution Approach 1:
The patent changes the material parameter of the white resist layer from epoxy-based to silicone-based resin. This material substitution provides high heat resistance and maintains reflectance stability under light irradiation, preventing the yellowing and brightness degradation that occurs with epoxy-based materials over time.
Solution Approach 2:
The patent employs a composite structure by forming both a silicone-based white resist layer and an acryl-based white resist layer. The acryl-based layer serves as an adhesion promoter between the silicone-based layer and the protective layer, creating a multi-layer composite system that combines the benefits of high heat resistance with improved bonding.
2Reliability
If a silicone-based white resist layer is used between the protective layer and circuit substrate, then heat resistance and aging resistance are improved, but the protective layer and circuit substrate easily delaminate due to poor adhesion
Solution Approach 1:
The patent introduces an acryl-based white resist layer as an intermediary between the silicone-based white resist layer and the protective layer. This intermediate layer acts as an adhesion promoter, forming strong bonds with both the silicone-based layer and the protective layer, thereby preventing delamination while preserving the high heat resistance of the silicone-based material.
Solution Approach 2:
The patent creates a multi-layer composite structure combining silicone-based and acryl-based white resist layers. The silicone-based layer provides heat resistance and aging resistance, while the acryl-based layer provides adhesion strength, achieving a synergistic effect where the composite structure overcomes the limitations of individual materials.
3Reliability
If a white resist layer is coated on the entire main surface of the circuit substrate, then circuit wiring is protected and light reflectance is increased, but the LED light emission is blocked when the layer covers the LED
Solution Approach 1:
The patent applies the white resist layer selectively rather than uniformly across the entire circuit substrate. By forming openings that expose the LED while covering the circuit wiring, the white resist layer provides protection and reflectance enhancement in appropriate locations without blocking the LED light emission path.
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 solution effectively reduces the risk of delamination and maintains consistent brightness by utilizing a non-silicone-based white resist layer to enhance adhesion and light reflectance, addressing the issues of degradation and adhesion in existing technologies.
Implementation Method 1
a silicone-based white resist layer covering the main surface and including: a first opening surrounding the light-emitting element; and a second opening different from the first opening
Implementation Method 2
a transparent protective layer covering the light-emitting element, the silicone-based white resist layer, and the second opening
Implementation Method 3
a non-silicone-based white resist layer found in a region inside the second opening in plan view
Data Source
AI summary
A light-emitting-element-equipped substrate includes: a circuit substrate including a main surface; a light-emitting element mounted on the main surface and electrically connected to the circuit substrate; a silicone-based white resist layer covering the main surface and including: a first opening surrounding the light-emitting element; and a second opening different from the first opening; and a transparent protective layer covering the light-emitting element, the silicone-based white resist layer, and the second opening.