Five-Element Lens Assembly with Concave First Surface

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Solution Overview

Problem

Conventional compact photographing optical lens assemblies for electronic devices face issues with damage from environmental exposure, limited effective range, and ineffective correction of peripheral aberrations such as astigmatism and distortion due to convex object-side surfaces and lack of bi-aspheric design in higher-order aspherical coefficients.

Innovation Solution

A photographing optical lens assembly with a concave object-side surface for the first lens element, negative refractive power for the fourth lens element, and bi-aspheric design for the fourth and fifth lens elements, along with specific curvature and focal length conditions, to prevent damage, extend the effective range, and correct peripheral aberrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the first lens element has a convex object-side surface, then the lens structure is simpler to manufacture, but the lens surface is exposed to the environment causing damage and decreased imaging quality

Engineering Contradiction:

Improvelens manufacturing simplicityVSAvoidlens durability and imaging quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent inverts the conventional convex object-side surface design to a concave object-side surface for the first lens element. This inversion protects the lens surface from environmental exposure and damage while maintaining manufacturing feasibility through the specific curvature design

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of moving object

If the fourth lens element has positive refractive power, then the lens system is more compact, but the effective range cannot be extended

Engineering Contradiction:

Improvelens assembly compactnessVSAvoideffective range of lens

Core Design Contradiction:

Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent changes the refractive power parameter of the fourth lens element from positive to negative. This parameter change extends the effective range of the lens system through divergent light beam capability while maintaining a compact overall structure through optimized element spacing

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If the fourth and fifth lens elements lack bi-aspheric design, then the manufacturing process is simpler, but peripheral aberrations such as astigmatism and distortion cannot be corrected effectively

Engineering Contradiction:

Improvelens element manufacturing simplicityVSAvoidaberration correction quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies bi-aspheric surface design to the fourth and fifth lens elements, replacing simple spherical surfaces with complex aspheric curvatures. This enables effective correction of peripheral aberrations including astigmatism and distortion while maintaining manufacturing feasibility through precision molding techniques

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 solution effectively prevents lens damage, enhances imaging quality, corrects astigmatism and distortion, and extends the effective range of the lens system while maintaining a compact size.

Implementation Method 1

a first lens element having an object-side surface being concave in a paraxial region

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

a fourth lens element with negative refractive power having an aspheric object-side surface and an aspheric image-side surface

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 3

the bi-aspheric design of the fourth and fifth lens elements can obtain the high order aspherical coefficient for optimal performance, so as to correct peripheral aberrations, such as, astigmatism and distortion, effectively

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS9733454B2Photographing optical lens assembly, imaging device and mobile terminal

Publication Date: 2017.08.15 LARGAN PRECISION

AI summary

A photographing optical lens assembly comprises, in order from an object side to an image side: a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with refractive power has a concave object-side surface in a paraxial region. The second lens element has refractive power. The third lens element has refractive power. The fourth lens element with negative refractive power has an object-side and an image-side surfaces both being aspheric. The fifth lens element with refractive power has an aspheric object-side surface and an aspheric image-side surface being concave in a paraxial region with at least one inflection point. The photographing optical lens assembly has a total of five lens elements with refractive power.