Wide-angle lens assembly with segmented rear group

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Solution Overview

Problem

Conventional wide-angle optical lens assemblies with inverse telephoto structures fail to completely correct aberrations and maintain a moderate total track length, especially in compact camera systems with high-pixel resolution demands.

Innovation Solution

A wide-angle optical lens assembly comprising a configuration of four lens elements with specific refractive powers and curvatures, including a first lens with negative power, a second with positive power, a third with positive power, and a fourth with positive power and a convex image-side surface made of plastic, optimized to correct aberrations and reduce total track length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional inverse telephoto structure with a one-element rear lens group is used, then the wide-angle characteristic is obtained, but the aberration cannot be corrected completely

Engineering Contradiction:

Improvewide-angle characteristicVSAvoidaberration correction

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The rear lens group is divided into multiple lens elements (second, third, and fourth lens elements) instead of using a single element. This segmentation allows each element to contribute to both the wide-angle characteristic and aberration correction, with the second element providing positive refractive power, the third element further correcting aberrations, and the fourth element with a convex image-side surface optimizing the overall performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses different materials for different lens elements, specifically making the fourth lens element from plastic material while other elements may use glass or different plastic compositions. This composite material approach allows optimization of each element for specific functions, combining the advantages of different materials to achieve both wide-angle performance and aberration correction.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the lens assembly is designed for high-pixel resolution, then the image quality improves, but the total track length increases

Engineering Contradiction:

Improveimage qualityVSAvoidtotal track length

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent applies specific design characteristics to local regions of the lens system. The fourth lens element is designed with a convex image-side surface and made of plastic material, creating a localized optimization zone that efficiently corrects high-order aberrations. This local quality enhancement allows high-pixel resolution performance without requiring a proportionally longer total track length, as the correction is achieved in a concentrated manner rather than distributed throughout the entire lens length.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If more lens elements are added to correct aberrations, then the aberration correction improves, but the device complexity increases

Engineering Contradiction:

Improveaberration correctionVSAvoidlens assembly structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent optimizes specific parameters of the lens elements to achieve effective aberration correction with a moderate number of elements. The fourth lens element is designed with a convex image-side surface and made of plastic material, creating a localized optimization zone that efficiently corrects high-order aberrations. This local quality enhancement allows high-pixel resolution performance without requiring a proportionally longer total track length, as the correction is achieved in a concentrated manner rather than distributed throughout the entire lens length.

Inventive Principle:

Principle #35Parameter changes

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 configuration enhances image quality, corrects high-order aberrations, and maintains a compact design while achieving a wide-angle characteristic, ensuring sufficient field of view and reducing the total track length of the lens assembly.

Implementation Method 1

The first lens element with a negative refractive power has a convex object-side surface and a concave image-side surface

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

The second lens element with a positive refractive power has a convex object-side surface and a concave image-side surface

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

the fourth lens element has at least one aspheric surface

Methodology Applied

Scientific EffectAspheric refraction: Refraction

Data Source

PatentUS8089698B1Wide-angle optical lens assembly

Publication Date: 2012.01.03 LARGAN PRECISION

AI summary

A wide-angle optical lens assembly comprises, in order from an object side to an image side: a first lens element with a negative refractive power having concave image-side surface, a second lens element with a positive refractive power, a third lens element with a positive refractive power, and a fourth lens element with a positive refractive power having convex image-side surface, at least one surface of the fourth lens element thereof being aspheric. By such arrangement, total track length and photosensitivity of the wide-angle optical lens assembly can be effectively reduced while retaining large field of view and superb image quality.