Variable-Focus Lens Gas Pressure Compensation
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Solution Overview
Problem
Variable-focus lenses with deformable housings face issues of excessive liquid pressure due to thermal expansion, leading to optical distortion and potential fracture of transparent plates, complicating manufacturing and precise positioning.
Innovation Solution
Incorporating a volume of gas in contact with one of the liquids, with retention measures to prevent it from entering the light path, and using electrowetting effects to deform the refractive interface, while maintaining a rigid structure by compensating for liquid expansion through compressible gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid housing structure is used for the variable-focus lens, then the structural stability and positioning precision are improved, but the internal pressure increases excessively due to liquid thermal expansion, causing optical distortion and potential fracture of transparent plates
Solution Approach 1:
The housing is divided into a rigid external structure for stability and a compliant internal pressure-regulating structure. The rigid housing provides structural stability and positioning precision, while the internal pressure-regulating structure (including deformable membranes or expandable elements) absorbs thermal expansion pressure, preventing it from transmitting to the transparent plates.
Solution Approach 2:
The housing structure incorporates elements that change their physical parameters (such as volume or stiffness) in response to temperature changes. When temperature increases and liquid pressure rises, the compliant internal structure deforms or expands, increasing its volume to accommodate the expanded liquid, thereby maintaining constant pressure on the transparent plates.
2Stress or pressure
If the housing structure is made deformable to compensate for liquid expansion, then the internal pressure is reduced, but the positioning precision and manufacturing complexity deteriorate
Solution Approach 1:
The housing is segmented into rigid external components for precise positioning and manufacturing, and a separate compliant internal pressure-regulating mechanism. This segmentation allows each part to perform its specialized function: the rigid external structure ensures manufacturing precision and assembly accuracy, while the internal mechanism handles pressure compensation independently.
Solution Approach 2:
An intermediary pressure-regulating mechanism is introduced between the liquid and the rigid housing structure. This intermediary (such as a deformable membrane or expandable element) absorbs the thermal expansion effects, mediating between the liquid's volume changes and the rigid housing, thereby protecting the precision components from pressure while maintaining positioning accuracy.
3Reliability
If special precautions are taken during assembly and temperature range is limited, then the risk of transparent plate fracture is reduced, but the ease of manufacture and operational flexibility deteriorate
Solution Approach 1:
The housing incorporates a pre-designed pressure-compensation mechanism that is built into the structure before assembly. This beforehand cushioning (such as pre-installed expandable elements or compliant layers) automatically absorbs thermal expansion pressure during normal operation, eliminating the need for special assembly precautions or temperature restrictions, thereby simplifying manufacturing while maintaining reliability.
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 limits internal pressure changes due to temperature variations, reducing the risk of optical distortion and allowing for easier manufacturing and precise positioning of lens components, while maintaining a rigid structure.
Implementation Method 1
The liquid lens includes a system for deforming the moveable refractive interface by electrowetting effects, thus making it possible to modify the optical power of the lens
Implementation Method 2
The pressure of the liquids in the housing may increase substantially, for example, during the operations of assembling the components of the housing, or, once the housing has been assembled, upon an increase in temperature of the liquids of the lens, which have higher expansion coefficients than the expansion coefficients of the constituent materials of the housing
Implementation Method 3
Incorporating a volume of gas in contact with one of the liquids, with retention measures to prevent it from entering the light path, and using electrowetting effects to deform the refractive interface, while maintaining a rigid structure by compensating for liquid expansion through compressible gas
Data Source
AI summary
The invention relates to a variable-focus lens (60) for focusing light rays in light paths passing through the lens along an optical axis (Δ). The lens comprises an arrangement of first and second immiscible liquids (67, 68) that have different refractive indices and are in contact over a moveable refractive optical interface (69), a volume of gas (72) in contact with one of said liquids, and a retention measure (70, 74) for keeping the volume of gas away from the light paths of the light rays passing through the lens for focusing.