Tri-Lens Imaging Unit for Compact Profile and Aberration Control
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Solution Overview
Problem
The challenge is to create a compact imaging lens unit for portable devices that maintains optical performance while achieving a lower profile, as reducing the number of lenses complicates aberration correction and manufacturing thinner plastic lenses is difficult.
Innovation Solution
The solution involves a tri-lens configuration with specific surface shapes for each lens, including a convex object side and concave image side for the first lens, a meniscus-shaped second lens, and a convex object side and concave image side for the third lens, all formed as plastic aspherical lenses by injection molding, allowing for aberration correction and a reduced profile without compromising optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the number of lenses is reduced to achieve a lower profile, then the profile height is reduced, but optical characteristics deteriorate due to inadequate aberration correction
Solution Approach 1:
The patent divides the imaging function into three separate lens elements (first lens with positive power, second meniscus lens, and third lens with negative power) arranged in sequence. Each lens element is designed with specific surface curvatures and powers to collectively correct various aberrations while maintaining a compact overall profile, thus resolving the contradiction between reduced lens count and adequate aberration correction.
Solution Approach 2:
Each lens element is designed with specific local optical properties: the first lens has a convex object-side surface and concave image-side surface with positive power, the second lens is meniscus-shaped, and the third lens has convex and concave surfaces with negative power. These localized design variations enable effective aberration correction across the entire optical system while maintaining a lower profile.
2Length of stationary object
If plastic lenses are made thinner to achieve a lower profile, then the profile height is reduced, but manufacturing difficulty increases due to injection molding limitations
Solution Approach 1:
The patent specifies precise parameter ranges for each lens element including focal length ratios (0.3 < f2/f1 < 1.5, 1.0 < |f3/f1| < 3.0), curvature radii relationships (R1/R2 between -5.0 and -0.5, R4/R5 between -5.0 and -0.5), and thickness ratios (0.1 < d2/d1 < 0.5, 0.1 < d3/d1 < 0.5). These parameter optimizations enable thin lens design that remains manufacturable through injection molding while achieving the desired lower profile.
3Reliability
If aspherical plastic lenses are used to correct aberration with limited lenses, then optical characteristics improve, but manufacturing complexity increases due to injection molding restrictions on thin lenses
Solution Approach 1:
The patent defines specific parameter ranges for aspherical surface coefficients (A4, A6, A8, A10, A12, A14) for each lens element, along with thickness ratios and curvature relationships. These controlled parameter variations enable effective aberration correction through aspherical surfaces while maintaining manufacturability by ensuring lens thickness remains within injection molding capabilities.
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
This configuration enables a lower profile imaging lens unit with improved optical performance, facilitating aberration correction and manufacturing simplicity, while maintaining the optical quality necessary for portable devices.
Implementation Method 1
The first lens includes a first surface located on the object side and being convex toward the object side and a second surface located on the image side and being concave toward the image side near the optical axis and convex toward the image side as the first lens rim becomes closer
Data Source
AI summary
An imaging lens unit which achieves a lower profile without adversely affecting the optical performance. The imaging lens unit includes a first lens, an aperture stop, a second lens, and a third lens arranged sequentially along the optical axis from the object side to the image side. The first lens includes a first surface located on the object side and being convex toward the object side and a second surface located on the image side and being concave toward the image side near the optical axis and convex toward the image side as the rim of the first lens becomes closer.