Transparent Composite Substrate Bonding Sapphire Glass
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Solution Overview
Problem
Sapphire substrates, despite their excellent abrasion and scratch resistance, are limited by high costs, low compression resistance, and brittleness, while existing composite substrates with adhesives suffer from poor transparency and adhesion issues, especially at high temperatures and pressures.
Innovation Solution
A method of manufacturing a transparent composite substrate by forming an inorganic material layer on a sapphire substrate, stacking it with a glass substrate, and applying an electrical field to create a binding layer without adhesives, using silicon or silicon dioxide layers and temperatures between 200°C to 400°C to achieve strong and stable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to bond sapphire substrate to glass substrate, then bonding is achieved, but transparency deteriorates and adhesion strength decreases at high temperature and pressure
Solution Approach 1:
The patent removes the adhesive layer from the bonding structure, replacing it with a direct bonding interface between the sapphire substrate and glass substrate. This extraction eliminates the transparency-detrimental adhesive while maintaining bonding through surface activation and direct contact at the interface.
Solution Approach 2:
The patent introduces a thin film layer (such as silicon oxide or silicon nitride) as an intermediary between the sapphire substrate and glass substrate. This intermediary layer facilitates bonding through plasma treatment or chemical vapor deposition, achieving strong adhesion without compromising optical transparency, as the film is sufficiently thin to maintain light transmission.
2Strength
If adhesive is used to bond sapphire substrate to glass substrate, then bonding is achieved, but bonding reliability deteriorates at high temperature and pressure
Solution Approach 1:
The patent eliminates the adhesive layer that degrades under high temperature and pressure, replacing it with a direct bonding interface. This extraction ensures bonding reliability by using the inherent thermal and pressure stability of the sapphire-glass interface, enhanced by surface activation treatments that create temperature-resistant bonds.
Solution Approach 2:
The patent changes the bonding parameters by applying plasma treatment or chemical vapor deposition to activate the substrate surfaces before bonding. This parameter change creates a surface state that forms strong, temperature-resistant bonds without requiring organic adhesives that would degrade under high temperature and pressure conditions.
3Strength
If adhesive is used to bond sapphire substrate to glass substrate, then bonding is achieved, but substrate thickness increases
Solution Approach 1:
The patent removes the adhesive layer from the bonding structure, eliminating the additional thickness that adhesives contribute. The direct bonding interface between sapphire and glass substrates achieves adhesion without the extra material layer, thereby reducing the overall substrate thickness while maintaining bonding strength.
4Strength
If sapphire substrate is used, then abrasion and scratch resistance are improved, but cost increases significantly
Solution Approach 1:
The patent creates a composite structure by bonding sapphire substrate to glass substrate, combining the abrasion and scratch resistance of sapphire with the cost-effectiveness and compression resistance of glass. This composite material approach allows the expensive sapphire to be used only where its specific properties are needed, while the less expensive glass provides structural support and reduces overall cost.
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 reduces the cost of sapphire substrates, enhances compression resistance, maintains transparency, and ensures strong bonding at high temperatures, making the composite suitable for wide application in touch panels.
Implementation Method 1
The sapphire substrate and the glass substrate are heated to form a binding layer at the contact surface
Implementation Method 2
an electrical field is applied to the sapphire substrate and the glass substrate, which the sapphire substrate is connected to an anode of the electrical field, and the glass substrate is connected to an cathode of the electrical field
Data Source
Figure 1~2
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Figure 5
AI summary
A transparent composite substrate includes a first transparent substrate, a second transparent substrate, and a binding layer bonding the first transparent substrate and the second transparent substrate.