Alumina Sputtered Bonding for Transparent Substrates
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Solution Overview
Problem
Existing methods for bonding transparent substrates, such as those used in optical devices and communication devices, often compromise light transmittance due to the use of organic adhesives and can generate bubbles at the bonding interface.
Innovation Solution
A method involving the formation of a thin film of aluminum oxide on the bonding surfaces of transparent substrates using a sputtering method, followed by contacting the films in air and heating the bonded substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If organic adhesives are used to bond transparent substrates, then bonding strength is achieved, but light transmittance deteriorates and bubbles are generated at the bonding interface
Solution Approach 1:
The invention changes the material parameter from organic adhesive to inorganic aluminum oxide film, and changes the bonding mechanism parameter from chemical adhesion to physical contact bonding enhanced by heating. This parameter transformation resolves the contradiction by eliminating the inherent optical absorption and bubble-generation issues of organic adhesives while achieving sufficient bonding strength through the inorganic film's physical properties and thermal processing
Solution Approach 2:
The invention replaces the chemical bonding mechanism of organic adhesives with a physical bonding mechanism using inorganic aluminum oxide film and thermal energy. The aluminum oxide film serves as a bonding interface that relies on physical contact and thermal activation rather than chemical adhesion, thereby eliminating the optical interference caused by organic materials while maintaining bonding functionality
2Strength
If organic adhesives are used to bond transparent substrates, then bonding is achieved, but organic materials are introduced which cannot be used in radiation environments
Solution Approach 1:
The invention changes the material composition parameter from organic to inorganic (aluminum oxide), fundamentally altering the material's interaction with radiation. Inorganic materials like aluminum oxide exhibit superior radiation resistance compared to organic adhesives, thereby resolving the contradiction between achieving bonding and maintaining radiation resistance in harsh environments
3Illumination intensity
If a thin film of aluminum oxide is formed by sputtering and substrates are bonded in air with heating, then light transmittance exceeds 90% and bonding strength is high, but process complexity increases
Solution Approach 1:
The aluminum oxide film serves as an intermediary layer between the transparent substrates, enabling bonding while maintaining optical transparency. This intermediary approach allows the process to achieve high transmittance (>90%) by using a thin inorganic film that does not significantly absorb light, while the sputtering and heating steps provide controlled bonding without requiring complex multi-layer adhesive systems
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 method achieves high bonding strength and maintains a high optical transmittance, exceeding 90% in some cases, without the need for organic adhesives, making it suitable for applications where organic materials cannot be used.
Implementation Method 1
forming a thin film of aluminum oxide by a sputtering method on bonding surfaces of the transparent substrates
Implementation Method 2
heating the bonded pair of transparent substrates
Data Source
AI summary
A method of bonding transparent substrates is provided, comprising: preparing a pair of transparent substrates; forming a thin film of aluminum oxide by a sputtering method, on a bonding surface of the transparent substrates; contacting the aluminum oxide thin films in the air to bond the pair of transparent substrates; and heating the bonded pair of transparent substrates.