Piezoelectric Fluid Lens Meniscus Control
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Solution Overview
Problem
Conventional fluid focus lenses face challenges with material choice and temperature stability due to the complexity of electro-wetting principles and pump systems, which are difficult to control effectively.
Innovation Solution
A piezoelectric fluid focus lens design that uses a cylindrical piezoelectric element within a fluid chamber, where the meniscus shape is altered by changing the voltage applied to the piezoelectric material, allowing for controlled changes in the meniscus shape without altering the fluid volumes, thus simplifying the system and improving temperature stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electro-wetting principles are used to control the meniscus shape, then the lens focus can be adjusted, but the system becomes difficult to control and material selection is limited
Solution Approach 1:
The patent replaces the electro-wetting system with a piezoelectric system. Instead of using electrical voltage to alter surface tension properties of fluids (electro-wetting), the invention uses piezoelectric elements that convert electrical signals directly into mechanical displacement. This mechanical substitution simplifies the control mechanism while maintaining the ability to adjust the meniscus shape and lens focus.
Solution Approach 2:
The patent introduces a coating on the piezoelectric element that acts as an intermediary. This coating has selective affinity for the first fluid versus the second fluid, creating a clear interface that enhances the piezoelectric effect and allows for more precise control of the meniscus position without the complexities of electro-wetting.
2Shape
If pump systems are used to change fluid volumes, then the meniscus shape can be altered, but the system becomes technically complicated and difficult to control
Solution Approach 1:
The patent replaces the pump system with a piezoelectric system. Instead of using pumps to mechanically transfer fluid between chambers (which requires complex valves, seals, and control mechanisms), the invention uses piezoelectric elements that directly displace the meniscus through mechanical expansion and contraction. This substitution eliminates the need for fluid transfer while achieving the same shape-changing effect.
Solution Approach 2:
The patent changes the control parameter from fluid volume (controlled by pumps) to piezoelectric element displacement (controlled by voltage). By applying different voltages to the piezoelectric element, the meniscus shape is adjusted through direct mechanical action rather than indirect fluid volume manipulation, simplifying the overall system.
3Ease of operation
If electro-wetting principles are used, then focus adjustment is possible, but temperature stability is compromised
Solution Approach 1:
The patent replaces the electro-wetting mechanism with a piezoelectric mechanism that is less sensitive to temperature variations. While electro-wetting relies on electrical properties of fluids that can change with temperature, the piezoelectric effect in solid ceramics is more stable across temperature ranges, improving overall system stability.
Solution Approach 2:
The patent uses immiscible fluids with different refractive indices that are selected for their stability and compatibility with the piezoelectric system. These fluids are chosen specifically because they maintain their properties across temperature variations, unlike the electro-wetting fluids that require precise temperature control.
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 piezoelectric fluid focus lens provides a more reliable and efficient method for changing the lens shape, reducing complexity and improving performance across various temperature conditions, while maintaining the same fluid volumes on either side of the meniscus.
Implementation Method 1
Changes in the source of electricity, or voltage potential, induce a change in the length of the piezoelectric material, and move the perimeter of the meniscus, thus inducing a change of the shape of the meniscus
Implementation Method 2
The perimeter of the meniscus is fixedly located on one side of the cylindrical element, for example, using a suitable coating that attracts the first fluid and repels the second fluid
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A variable focus lens (10) comprises a fluid chamber (12) having an optical axis (20). One or more piezoelectric element (22) is disposed about the optical axis within a portion of the fluid chamber. First and second fluids (24,26) are disposed within another portion the fluid chamber and in contact with one another over a meniscus (28,36) extending transverse the optical axis, the first and second fluids being substantially immiscible and having different indices of refraction. The perimeter of the meniscus is fixedly located on a surface in relationship to the one or more piezoelectric element, wherein responsive to application of a voltage potential (32) to the one or more piezoelectric element, the one or more piezoelectric element controllably alters one or more of (i) a shape of the meniscus or (ii) a translation of the meniscus.