Liquid Lens Window Bonding for Thermal Exposure Resistance
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Solution Overview
Problem
Conventional liquid lenses fail under thermal exposure requirements, particularly in automotive and military applications, due to adhesive failure between transparent windows and metal bases when subjected to high temperatures.
Innovation Solution
A liquid lens design with specific window dimensions and adhesive formulation, including a thermoset polymer with a hardener-to-polymer ratio of 0.4:10 to 0.9:10, and a lower window edge height of 0.3 mm to 1.2 mm, to enhance thermal exposure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid lenses are used in thermal environments, then they can be manufactured with standard adhesives, but the adhesives fail under prolonged exposure to high temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by specifying a thermoset polymer with a hardener-to-polymer ratio between 0.4:10 and 0.9:10. This parameter modification enables the adhesive to maintain bond strength at elevated temperatures up to 105°C for 1000 hours, resolving the thermal exposure resistance issue while preserving adhesive strength
Solution Approach 2:
The patent uses a composite adhesive system combining thermoset polymer and hardener in specific ratios. This composite material approach creates a cross-linked polymer structure that provides both strong bonding and thermal stability, simultaneously addressing adhesive strength and thermal resistance requirements
2Reliability
If the lower window edge height is increased to improve sealing, then thermal exposure resistance improves, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the lower window edge height parameter to a specific range (0.3mm to 1.2mm) that provides adequate sealing and thermal resistance while remaining manufacturable. This parameter optimization balances performance requirements with manufacturing feasibility, avoiding excessive complexity
3Ease of manufacture
If standard adhesive formulations are used, then manufacturing is simplified, but thermal exposure resistance deteriorates
Solution Approach 1:
The patent modifies the adhesive formulation parameters by specifying a thermoset polymer with controlled hardener-to-polymer ratios (0.4:10 to 0.9:10). This parameter change maintains ease of manufacture through standard dispensing techniques while dramatically improving thermal exposure resistance to withstand 105°C for 1000 hours
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 design provides improved reliability and stability under thermal stress, allowing the lenses to operate without failure for extended periods, suitable for demanding applications like automotive and military uses.
Implementation Method 1
first and second immiscible fluids defining an interface moveable by electrowetting
Implementation Method 2
the adhesive is a thermoset polymer comprising a hardener and a polymer at a ratio from about 0.4:10 to about 0.9:10 of the hardener to the polymer
Data Source
AI summary
A liquid lens device includes: first and second immiscible fluids defining an interface moveable by electrowetting; a cap portion; a base portion; a gasket positioned between the cap portion and the base portion; an upper window positioned within the cap portion; and a lower window positioned within the base portion, the windows facing and substantially parallel to each other. The lower window comprises opposing primary surfaces and an edge. The lower window is joined to the base portion with an adhesive, the adhesive positioned in contact with a portion of one or more of the primary surfaces and the edge. The fluids are sealed within the cap portion, base portion, gasket and windows. Further, a height of the edge of the lower window is greater than 0.3 mm and less than 1.2 mm.