Five-Lens Plastic Optical System Aberration Correction

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Solution Overview

Problem

Miniaturization and lightweight requirements of mobile communications terminals pose challenges in implementing camera modules with high resolution and performance, particularly due to issues with chromatic aberrations and optical system brightness when using plastic lenses instead of glass.

Innovation Solution

An optical system comprising five plastic lenses with specific refractive powers and shapes, including a first lens with negative refractive power and a meniscus shape convex toward the object, a second lens with positive refractive power and both surfaces convex, a third lens with negative refractive power and concave surfaces, a fourth lens with positive refractive power and a meniscus shape convex toward the image, and a fifth lens with negative refractive power and inflection points, satisfying several conditional expressions to improve aberration correction and sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If plastic lenses are used instead of glass lenses, then weight is reduced and manufacturing cost is lowered, but chromatic aberrations worsen and optical system brightness decreases

Engineering Contradiction:

Improveweight of camera moduleVSAvoidchromatic aberrations

Core Design Contradiction:

Weight of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite lens design where the second lens uses a plastic material with a specific refractive index range (1.65-1.75) and the third lens uses a plastic material with a different refractive index range (1.50-1.60). This combination of different plastic materials allows correction of chromatic aberrations while maintaining the weight and cost advantages of plastic lenses over glass lenses.

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If five or more lenses are configured in the optical system, then resolution is improved, but device complexity increases and miniaturization becomes more difficult

Engineering Contradiction:

Improveresolution of camera moduleVSAvoidcomplexity of optical system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies specific parameter constraints to achieve high resolution with a five-lens configuration. The air gap between the third and fourth lenses is set to be more than 8 times the air gap between the second and third lenses (T34/T23 > 8.0). Additionally, the focal length of the first lens is constrained to -0.10f < f1 < -0.05f, and the Abbe number of the third lens is constrained to 20 < v3 < 40. These parameter optimizations enable high resolution while maintaining manageable system complexity.

Inventive Principle:

Principle #35Parameter changes

3Volume of moving object

If the air gap between lenses is reduced for miniaturization, then overall module size is reduced, but aberration correction capability deteriorates

Engineering Contradiction:

Improvesize of camera moduleVSAvoidaberration correction

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies local optimization by creating a large air gap specifically between the third and fourth lenses (T34 > 8.0 × T23), while maintaining compact dimensions elsewhere in the system. This localized space allocation allows the optical system to maintain aberration correction capability through the larger separation distance, while the overall module remains miniaturized due to efficient space utilization in other regions.

Inventive Principle:

Principle #3Local quality

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 optical system enhances aberration correction, improves lens sensitivity, and reduces manufacturing costs while maintaining high resolution, enabling the miniaturization of camera modules with improved optical performance.

Implementation Method 1

a first lens (10) having negative refractive power, an object-side surface of which is convex toward an object

Methodology Applied