Gradient Buffer Layer Bonding for Transparent Substrate Joints
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Solution Overview
Problem
The bonding of light-transmissive members using adhesives, such as acrylic polymers, often results in deterioration due to ultraviolet light, and existing adhesive-free methods like atomic diffusion bonding compromise light transmission properties.
Innovation Solution
A method involving a buffer layer with a metallic element concentration distribution changing in the film thickness direction, formed by oxygen supply layers and metal films, allows for adhesive-free bonding of substrates while maintaining high light transmission and electrical insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive including acrylic polymer is used to bond light-transmissive substrates, then bonding strength is improved, but light transmission property deteriorates and adhesive deteriorates due to ultraviolet light
Solution Approach 1:
The patent removes the adhesive layer from the bonding structure entirely, replacing it with a direct bonding interface between substrates. This extraction eliminates the source of UV deterioration while maintaining bonding functionality through alternative mechanisms.
Solution Approach 2:
The patent introduces a buffer layer as an intermediary between substrates to enable bonding without adhesive. This buffer layer mediates the bonding process, allowing direct substrate-to-substrate bonding while preventing the harmful effects of adhesive materials.
2Reliability
If atomic diffusion bonding method is used to bond substrates without adhesive, then resistance to deterioration is improved, but light transmission property worsens
Solution Approach 1:
The patent applies local quality by creating a buffer layer with specific localized properties (controlled thickness and material composition) at the bonding interface. This localized structure maintains transparency in the optical path while providing the necessary bonding functionality only where needed.
Solution Approach 2:
The patent changes physical parameters of the buffer layer, specifically controlling its thickness to be within a range that allows sufficient light transmission while maintaining bonding strength. The buffer layer's material composition and thickness are optimized to balance optical and mechanical requirements.
3Ease of manufacture
If adhesive is used to bond substrates, then ease of manufacture is improved, but light transmission property and reliability worsen
Solution Approach 1:
The patent extracts the adhesive component from the manufacturing process, replacing it with a buffer layer structure that enables bonding without requiring adhesive materials. This simplifies the material system while improving long-term reliability.
Solution Approach 2:
The patent replaces the chemical bonding mechanism of adhesives with a physical bonding mechanism using the buffer layer structure. This substitution eliminates chemical deterioration issues while maintaining bonding functionality.
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 enhances the reliability of bonded parts by achieving high light transmission and electrical insulation properties without adhesives, addressing the limitations of existing methods.
Implementation Method 1
The two substances are bonded with no adhesive by using an atomic diffusion bonding method
Implementation Method 2
bonding of the first substrate and the second substrate with no adhesive, and makes it possible to improve a light transmission property of a bonded part
Data Source
AI summary
There is provided a functional element that includes a first substrate, a second substrate disposed to face the first substrate, and a buffer layer provided between the first substrate and the second substrate. The buffer layer has, in a layer thereof, a distribution of concentration of a metallic element. The distribution changes in a film thickness direction.