Five-Element Imaging Lens Compact Length High Resolution
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Solution Overview
Problem
Conventional imaging lenses for devices like smartphones and tablet terminals are too long and do not adequately meet the demands for high pixel counts and high resolution, as they have an unsuitable ratio of overall lens length to focal length and increased pixel size, leading to reduced sensitivity and larger size.
Innovation Solution
A five-element imaging lens configuration with specific refractive powers and surface shapes, including a first lens with positive power and convex surface, a second lens with negative power and concave surface, a third lens with negative power and meniscus shape, a fourth lens with positive power and concave surface, and a fifth lens with negative power and aspherical concave surface, optimized to satisfy conditional expressions for reduced overall length and improved imaging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging lenses are used to meet high pixel count demands, then image sensor size must be increased, but overall lens length becomes too long
Solution Approach 1:
The patent applies parameter changes by optimizing the focal length ratio between the first and fifth lenses (0.91 < f/f1f/f5 < 1.05) and controlling the overall lens length to focal length ratio (TTL/f) within 1.25-1.35. These parameter optimizations enable the lens to achieve high pixel count performance (5MP or greater) while maintaining a compact overall length suitable for portable devices with large image sensors.
Solution Approach 2:
The imaging lens is segmented into five distinct lens elements with specific refractive power distributions: first lens (positive), second lens (negative), third lens (negative), fourth lens (positive), and fifth lens (negative). This segmentation allows each element to contribute differently to the overall optical performance, enabling high resolution imaging while controlling the total lens length through coordinated design of individual elements.
2Measurement precision
If image sensor size is increased for higher pixel counts, then sensitivity is reduced, but lens complexity increases
Solution Approach 1:
The patent controls the F-number within 1.8-2.2 through optimized lens parameter design, including the focal length ratios and surface curvatures. This F-number optimization ensures sufficient light gathering capability and sensor sensitivity even when using large image sensors with high pixel counts (5MP or greater), thereby maintaining reliability while achieving high resolution.
3Length of moving object
If overall lens length is reduced for compact devices, then imaging performance at peripheral angles deteriorates, but device thickness is reduced
Solution Approach 1:
The patent employs aspherical surfaces on the first, third, and fifth lenses to correct optical aberrations. The aspherical shapes enable effective control of spherical aberration, coma, and astigmatism across the entire field of view including peripheral angles, while maintaining a compact overall lens length. This curvature optimization ensures high imaging performance throughout the image area without increasing lens length.
Solution Approach 2:
The patent optimizes multiple parameters simultaneously including focal length ratios (f/f1f/f5), overall length to focal length ratio (TTL/f), and F-number to achieve a balanced design. These parameter changes enable the lens to maintain excellent imaging performance from central to peripheral angles while keeping the overall length compact for portable device integration.
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 achieves a small F-number and high imaging performance from central to peripheral angles of view while reducing the overall lens length, enabling high-resolution image capture with a compact design suitable for devices with large image sensors.
Implementation Method 1
a first lens L1 having a positive refractive power and a convex surface on the object side, a second lens L2 having a negative refractive power and a concave surface on the object side, a third lens L3 having a negative refractive power and a meniscus shape with a convex surface on the object side, a fourth lens L4 having a positive refractive power and a meniscus shape with a concave surface on the object side, and a fifth lens L5 having a negative refractive power
Data Source
AI summary
An imaging lens, substantially consisting of five lenses, composed of a positive first lens with a convex surface on the object side, a negative second lens with a concave surface on the object side, a third lens having a negative meniscus shape with a convex surface on the object side, a fourth lens having a positive meniscus shape with a concave surface on the object side, and a negative fifth lens with a concave surface on the image side, the image side surface having an aspherical shape with at least one inflection point located inward in a radial direction from the intersection between the image side surface and a principal ray of the maximum angle of view toward the optical axis, disposed in order from the object side, and satisfies given conditional expressions.