Five-Element Aspheric Lens System for Compact Image Capture

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Solution Overview

Problem

Conventional image capturing lens systems for portable electronic devices, such as smartphones and PDAs, face challenges in achieving high image quality and compactness due to excessive total track length and inability to correct aberrations effectively, especially with increasing pixel size demands.

Innovation Solution

A compact image capturing optical lens system comprising five lens elements with specific refractive powers and aspheric surfaces, including a first positive refractive power lens, a second negative refractive power lens with concave surfaces, a third negative refractive power lens with concave and aspheric surfaces, a fourth positive refractive power lens made of plastic with aspheric surfaces, and a fifth negative refractive power lens with a concave image-side surface and inflection points, optimized to reduce total track length and correct aberrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional five-lens element lens system is used to improve image quality, then image quality is improved, but total track length becomes excessively long

Engineering Contradiction:

Improveimage qualityVSAvoidtotal track length

Core Design Contradiction:

Manufacturing precisionVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the refractive powers, curvature radii, and axial distances of the five lens elements. Specifically, it sets the second lens element with negative refractive power, the third with negative refractive power and concave object-side surface, and establishes specific relationships between curvature radii (R3, R4, R5, R6, R7, R8) and axial distances (T23, T34, T45) to achieve compact total track length while maintaining high image quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes aspheric surfaces on multiple lens elements (second, third, fourth, and fifth lens elements) to correct optical aberrations more effectively than spherical surfaces. The aspheric surfaces allow for better control of light rays, enabling high image quality with a reduced number of lens elements and shorter total track length

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Length of moving object

If the number of lens elements is reduced to shorten total track length, then total track length is reduced, but aberration correction capability deteriorates

Engineering Contradiction:

Improvetotal track lengthVSAvoidaberration correction

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs a composite design combining glass and plastic lens elements. The fourth and fifth lens elements are made of plastic material, which allows for cost-effective aspheric surface fabrication. This composite approach enables complex aberration correction with fewer elements while maintaining compact size

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent incorporates aspheric surfaces on the second, third, fourth, and fifth lens elements to provide superior aberration correction compared to traditional spherical surfaces. The aspheric profiles enable precise control of off-axis light rays, correcting astigmatism and other aberrations effectively within a compact five-element configuration

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 system achieves reduced photosensitivity, corrected aberrations and astigmatism, improved image resolution, and a compact design suitable for portable devices by leveraging the refractive powers and aspheric surfaces of the lens elements.

Implementation Method 1

a first lens element with positive refractive power; a second lens element with negative refractive power; a third lens element with negative refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8339718B1Image capturing optical lens system

Publication Date: 2012.12.25 LARGAN PRECISION

AI summary

This invention provides an optical lens system comprising: a first lens element with positive refractive power; a second lens element with negative refractive power; a third lens element with negative refractive power having a concave object-side surface and at least one of the object-side surface and the image-side surface thereof being aspheric; a plastic fourth lens element having at least one of the object-side surface and the image-side surface thereof being aspheric; a plastic fifth lens element having a concave image-side surface, at least one of the object-side surface and the image-side surface thereof being aspheric, and at least one inflection point is formed on at least one of the object-side surface and the image-side surface thereof. By such arrangement, photosensitivity and total track length of the system can be reduced, and the aberration and astigmatism of the system can be effectively corrected. Moreover, high image resolution can be obtained.