Wafer-Level Five-Aspheric Lens System for Wide Viewing Angle
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Solution Overview
Problem
Conventional small digital camera modules face limitations in achieving wide viewing angles greater than 70 degrees while maintaining a short overall lens length, due to optical aberrations that are not compatible with image sensors of enhanced resolution.
Innovation Solution
A five-aspheric-surface wafer-level lens system is designed with specific substrate and lens configurations, including concave and convex aspheric surfaces, and reflow-compatible materials, to achieve a wide viewing angle of 90 degrees or more with a short overall length of less than 5 mm, while maintaining good optical quality and low cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional molded one-piece plastic lens is used, then the lens structure is simple and manufacturing is easy, but the viewing angle is limited to between 60 and 70 degrees and optical aberrations cannot be corrected for high-resolution sensors
Solution Approach 1:
The single lens is divided into multiple lenses (first lens, second lens, third lens) with different functions. The first lens has a negative optical power with an aspheric surface to reduce distortion, the second lens has positive optical power for focusing, and the third lens corrects optical aberrations. This segmentation allows each lens to be optimized for specific optical functions while maintaining manufacturability through wafer-level fabrication.
Solution Approach 2:
The first lens incorporates an aspheric surface instead of a conventional spherical surface. This asymmetric geometry allows for better correction of optical aberrations including distortion and field curvature, enabling wide viewing angles (90 degrees or more) while maintaining image quality suitable for high-resolution sensors. The aspheric surface is achieved through wafer-level molding and curing processes.
2Adaptability or versatility
If the viewing angle is increased to greater than 70 degrees, then wider field of view is achieved, but optical aberrations increase and overall lens length must be increased
Solution Approach 1:
The optical parameters of the lens system are carefully controlled to achieve wide viewing angle with short length. Specifically, the ratio of focal lengths (0.2 < F1/F2 < 0.5), the optical power distribution, and the aspheric surface parameters are optimized. These parameter changes enable the system to achieve 90 degrees or more viewing angle while maintaining overall lens length of less than 5 mm and effective focal length of 2.0 mm or less.
3Manufacturing precision
If multiple lenses with different materials and surfaces are used, then optical performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Multiple lenses with different optical functions are combined into a single integrated lens system manufactured at wafer-level. The first lens, second lens, and third lens are formed on the same substrate using molding and curing processes, allowing them to be positioned precisely relative to each other. This merging approach maintains optical performance while simplifying manufacturing compared to assembling separate lenses.
Solution Approach 2:
The wafer-level manufacturing process serves multiple functions: it forms multiple lenses with different optical powers and aspheric surfaces, positions them precisely relative to each other, and creates a compact integrated structure. This multi-functional approach achieves complex optical performance with a unified manufacturing process rather than separate fabrication and assembly steps.
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 lens system achieves a wide viewing angle of 90 degrees or more, a short overall length of less than 5 mm, and nominal optical aberrations, ensuring compatibility with high-resolution image sensors and meeting the requirements of low cost and optical performance.
Implementation Method 1
a first lens having a concave aspheric surface and a focal length F1 and a second lens having a convex aspheric surface facing the first lens
Data Source
AI summary
A wafer-level lens system includes a first substrate, a first lens having a planar surface in contact with the first substrate and a concave aspheric surface, a second substrate, a second lens having a convex aspheric surface facing the first lens and a planar surface in contact with the second substrate, a third lens having a planar surface in contact with the second substrate and a concave aspheric surface, a third substrate, a fourth lens having a convex aspheric surface facing the third lens and a planar surface in contact with the third substrate, and a fifth lens having a planar surface in contact with the third substrate and a concave aspheric surface.