Wafer-Level Aspherical Lens for Miniaturized Optical Performance
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Solution Overview
Problem
Conventional wafer-level miniature image capture lenses face challenges in miniaturization due to difficulties in controlling lens surface accuracy and handling tiny components, resulting in inferior optical performance compared to conventional 3D lenses, especially in terms of aberration and modulation transfer function, especially at higher Nyquist frequencies.
Innovation Solution
A miniature image capture lens system is designed with an aperture diaphragm and a wafer-level lens configuration comprising aspherical lenses arranged in specific groups on substrates, meeting specific focal length and thickness conditions to enhance optical performance, including a first lens group acting as a meniscus lens and a second group as a field corrector to match the image sensor's chief ray angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If wafer-level lens modules are used for miniaturization, then device size is reduced, but optical performance deteriorates due to difficulty in controlling lens surface accuracy and handling tiny components
Solution Approach 1:
The wafer-level lens module is divided into multiple discrete lens elements (first lens, second lens, third lens, fourth lens) arranged in specific groups. This segmentation allows each lens element to be independently optimized and positioned, enabling better control over optical performance while maintaining the miniaturized wafer-level form factor.
Solution Approach 2:
Each lens element is designed with specific local optical properties including aspherical surfaces with tailored curvature radii and refractive indices. The first lens group (positive meniscus) and second lens group (negative meniscus) have different local optical characteristics to correct specific aberrations, allowing optimization of optical performance in different regions of the compact lens system.
2Manufacturing precision
If conventional 3D lens structures are used, then optical performance is maintained, but device size increases
Solution Approach 1:
The patent transitions from conventional three-dimensional lens structures to a two-and-a-half-dimensional wafer-level configuration where multiple thin lens plates are stacked and singulated. This dimensional change enables miniaturization by reducing the overall thickness and volume while maintaining optical functionality through careful design of the stacked lens arrangement.
Solution Approach 2:
The patent employs aspherical lens surfaces with specific curvature radii, refractive indices, and thickness parameters to achieve comparable optical performance in a miniaturized form factor. By optimizing parameters such as the ratio of total track length to effective focal length (0.5-1.5) and the spacing between lens elements, the design maintains aberration control and modulation transfer function while reducing device size.
3Manufacturing precision
If aspherical lenses are used in wafer-level configuration, then aberration control is improved, but manufacturing complexity increases
Solution Approach 1:
The complex optical correction requirements are divided among multiple aspherical lens elements in two groups, with each element responsible for specific aberration corrections. This segmentation of optical functions simplifies the design of individual lens elements while achieving comprehensive aberration control for the entire system.
Solution Approach 2:
The patent utilizes aspherical lens surfaces with precisely controlled curvature profiles to correct optical aberrations. The aspherical shapes allow for better aberration control compared to spherical surfaces, and the specific curvature radii are optimized to balance manufacturing feasibility with optical performance in the wafer-level configuration.
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 design achieves comparable optical performance to conventional 3D lenses while allowing for miniaturization, with improved aberration control and modulation transfer function, and is reflow solderable in Pb-free soldering processes.
Implementation Method 1
a first lens disposed on a first side of the first substrate and a second lens disposed on a second side of the first substrate
Data Source
AI summary
A miniature image capture lens is disclosed, comprising an aperture diaphragm having an aperture through which an image is captured and a wafer-level lens system, comprising a first lens group including a first substrate, a first lens disposed on a first side of the first substrate and a second lens disposed on a second side of the first substrate, and a second lens group including a second substrate, a third lens disposed on a first side of the second substrate and a fourth lens disposed on a second side of the second substrate. The first lens, the second lens, the third lens and the fourth lens are aspherical and the miniature image capture lens meets the following condition: L/fe<1.6; f1/fe=0.5˜1.5; f2/fe=−1˜−3; Tgroup2/TBFL=0.8˜1.2; Tair/Tgroup2=0.4˜0.8; L: total track length (TTL) from the first lens to an image plane fe: effective focal length of whole lens system f1: effective focal length of the first lens f2: effective focal length of the second lens Tgroup2: thickness of the second lens group Tair: distance between the second lens and the third lens Tlens2: thickness of the second lens Tlens2: thickness of the second lens TBFL: back focal length from the last lens surface to the image plane.