Liquid Lens Thermal Drift Compensation
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Solution Overview
Problem
Liquid lenses face thermal drift issues due to temperature-induced expansion of the liquid, leading to changes in focal length, which existing technologies have not effectively addressed.
Innovation Solution
A lens design featuring a transparent, elastically deformable membrane and a rigid member, with a lens shaping element that adjusts the membrane's curvature to maintain a constant focal length, using mechanisms such as thermal expansion compensation and refractive index changes, to minimize thermal drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the liquid lens is used over a temperature range, then the liquid expands with increasing temperature, but this leads to thermal drift of the focal length
Solution Approach 1:
The patent changes the physical parameters of the system by introducing a compensation liquid with different thermal expansion properties. The compensation liquid's volume changes with temperature in a way that counteracts the expansion of the original liquid, thereby stabilizing the overall focal length of the lens system across temperature variations.
Solution Approach 2:
The patent uses a composite approach by combining two different liquids (the original liquid and the compensation liquid) with different thermal expansion characteristics. This composite liquid system allows the beneficial property of liquid adaptability while compensating for the harmful thermal expansion effect through the interaction of the two liquids.
2Reliability
If a compensation mechanism is added to stabilize focal length, then thermal drift is reduced, but the device complexity increases
Solution Approach 1:
The compensation liquid serves multiple functions simultaneously: it compensates for thermal expansion, maintains volume balance, and preserves the optical properties needed for lens operation. This multi-functionality allows the system to achieve thermal stability without adding separate mechanical compensation devices, thereby limiting the increase in structural complexity.
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 solution effectively stabilizes the focal length of the lens, ensuring it remains constant over a temperature range of at least 30°C, reducing focal power changes to less than 0.5 dpt, thereby addressing the thermal drift issue.
Implementation Method 1
the liquid expands with increasing temperature leading to an increasing curvature of said area of the membrane which finally leads to a thermal drift of the focal length of the lens
Implementation Method 2
a lens shaping element that contacts the membrane and defines an area of said membrane, which area has an adjustable curvature for adjusting the focal length of the lens
Data Source
AI summary
The invention relates to a lens, comprising a container (100) defining a volume (V) which is filled with a transparent liquid (2), wherein the container (10) comprises a transparent and elastically deformable membrane (20) and a rigid member (30), wherein the membrane (20) and the rigid member (30) delimit said volume (V), and a lens shaping element (200) that contacts the membrane (20) and defines an area (21) of said membrane (20), which area (21) has an adjustable curvature for adjusting the focal length of the lens (1). According to the invention, the lens (1) is configured to compensate a thermal expansion of the liquid (2) and/or a change of the refractive index of the liquid (2) due to an increased temperature of the liquid (2) in order to reduce an unwanted thermally induced change of the focal length of the lens (1).