Five-Lens Imaging System with Aspheric Fifth Element for Compact High-Resolution Design

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Solution Overview

Problem

There is a demand for a compact imaging lens with high resolution performance that can cover a wide angle of view while minimizing the total length, particularly for devices like cellular phones and smartphones, where existing lenses composed of five or six lenses are too large and cumbersome.

Innovation Solution

The imaging lens is optimized with a configuration of five lenses, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens, a fourth lens with positive refractive power, and a fifth lens with negative refractive power, where the fifth lens has aspheric surfaces and a meniscus shape convex toward the object side, along with specific focal length ratios and an aperture stop placement to reduce the total length and enhance optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the imaging lens is composed of five or six lenses to achieve high resolution performance, then the imaging performance is improved, but the total length of the lens increases

Engineering Contradiction:

Improveimaging performanceVSAvoidtotal length

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by optimizing the refractive powers and focal lengths of individual lens elements. Specifically, it sets the refractive power of the fourth lens to be 1.5 to 2.5 times that of the third lens, and the focal length of the fifth lens to be 0.8 to 1.2 times that of the fourth lens. These parameter optimizations enable high imaging performance with a reduced total length compared to conventional five-lens designs.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes aspheric surfaces on the fifth lens to correct optical aberrations. By employing aspheric curvature instead of simple spherical surfaces, the design achieves improved imaging performance across the field of view while maintaining a compact form factor, thereby reducing the total lens length.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the number of lenses is increased to cover wide angle of view, then the angle of view coverage is improved, but the device complexity increases

Engineering Contradiction:

Improveangle of view coverageVSAvoidnumber of lenses

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the optical system into five distinct lens elements with specific refractive power relationships. The third lens has negative refractive power, the fourth lens has positive refractive power that is 1.5 to 2.5 times that of the third lens, and the fifth lens has positive refractive power. This segmentation allows wide angle of view coverage while maintaining manageable complexity through optimized element arrangement.

Inventive Principle:

Principle #1Segmentation

3Length of moving object

If the total length of the lens is decreased for miniaturization, then the compactness is improved, but the imaging performance deteriorates

Engineering Contradiction:

Improvetotal lengthVSAvoidimaging performance

Core Design Contradiction:

Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent achieves compactness without performance loss through precise parameter optimization. The focal length of the fifth lens is set to be 0.8 to 1.2 times that of the fourth lens, and the refractive power relationships are carefully controlled. These parameter changes enable a reduced total length while maintaining high resolution performance across the entire field of view.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The aspheric surfaces on the fifth lens enable compact design by correcting field curvature and distortion aberrations that would otherwise require additional lens elements. This curvature optimization allows the system to achieve both short total length and high imaging performance simultaneously.

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

This configuration achieves high resolution performance across the central and peripheral angles of view while significantly reducing the total length of the lens system, enabling high-quality imaging with a more compact form factor suitable for mobile devices.

Implementation Method 1

a fifth lens that has a negative refractive power and has an object side surface and an image side surface which have aspheric shapes

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

an object side surface and an image side surface which have aspheric shapes

Methodology Applied

Scientific EffectAspheric surface optics: Refraction

Data Source

PatentUS9235028B2Imaging lens and imaging apparatus including the imaging lens

Publication Date: 2016.01.12 JIANGXI JINGCHAO OPTICAL CO LTD

AI summary

An imaging lens substantially consists of, in order from an object side, five lenses of a first lens that has a positive refractive power and is convex toward the object side, a second lens that has a negative refractive power, a third lens, a fourth lens that has a positive refractive power, and a fifth lens that has a negative refractive power and has an object side surface and an image side surface which have aspheric shapes. Further, the imaging lens satisfies predetermined conditional expressions.