Liquid Lens Imaging Module Using Functional Optics for Thermal Defocus
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Solution Overview
Problem
Conventional lens modules with liquid lenses suffer from temperature-related defocus issues due to thermal expansion of plastic lenses, affecting effective focal length and flange back length.
Innovation Solution
Incorporating a functional optical element with a refractive index temperature coefficient between -9×10^-5 and 9×10^-5, such as a glass lens, and a diffractive optical element with a low temperature-sensitive optical diffraction grating, to stabilize the imaging lens group and correct chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed-focal-length plastic lens group is used in the photographing module, then the device complexity is reduced and ease of manufacture is improved, but the lens group expands due to heat from surrounding elements, causing effective focal length and flange back length to change with temperature, resulting in defocus phenomenon
Solution Approach 1:
The patent applies parameter changes by selecting a glass lens material with a specific refractive index temperature coefficient (β) within the range of -9×10^-5 to 9×10^-5. This parameter selection ensures that the glass lens compensates for thermal expansion effects, maintaining stable effective focal length and flange back length across temperature variations, thereby resolving the defocus phenomenon while keeping the lens structure simple
Solution Approach 2:
The patent employs composite materials by combining glass lens elements with specific optical properties into the imaging lens group. The glass lens with controlled refractive index temperature coefficient works in conjunction with other lens elements to create a composite optical system that is thermally stable, addressing the reliability issue without significantly increasing manufacturing complexity
2Reliability
If the refractive index temperature coefficient of the functional lens is controlled within -9×10^-5 to 9×10^-5, then the temperature effect is improved and imaging stability is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a parameter range (β between -9×10^-5 to 9×10^-5) rather than a single precise value, which balances temperature stability requirements with manufacturing feasibility. This range allows sufficient thermal compensation while providing manufacturing tolerance, reducing the burden on manufacturing precision
Solution Approach 2:
The patent applies local quality by focusing the precision requirement specifically on the refractive index temperature coefficient parameter of the glass lens, while other lens parameters can have standard tolerances. This targeted approach to quality control addresses temperature stability without unnecessarily increasing overall manufacturing precision requirements
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 improves thermal stability and reduces temperature sensitivity, ensuring consistent imaging quality by synchronizing focal length changes with temperature fluctuations.
Implementation Method 1
The fixed-focal-length plastic lens group is prone to expand due to heat emitting of a surrounding element... As a result, an effective focal length (Effective Focal Length) and a flange back length (Flange Back Length) of the lens group change with a temperature
Implementation Method 2
a refractive index temperature coefficient β of the functional lens meets: -9×10^-5≤β≤9×10^-5
Implementation Method 3
a diffractive optical element with a low temperature-sensitive optical diffraction grating
Data Source
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AI summary
This application provides a lens module and an electronic device. The lens module includes an imaging lens group, a light filter, and an image sensor, the imaging lens group includes a plurality of lenses whose optical axes mutually overlap, the plurality of lenses include a liquid lens, a plastic lens, and a functional optical element, the functional optical element is a functional lens and/or a diffractive optical element, and a refractive index temperature coefficient β of the functional lens meets: -9:optical-5≤β≤9×10-5. According to the lens module and the electronic device provided in embodiments of this application, the functional optical element is disposed in the imaging lens group including the liquid lens, so that a temperature effect problem of a lens module including a liquid lens in the conventional technology can be resolved.