Zoom Lens Third Unit Cemented Lenses Aberration Control

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Solution Overview

Problem

Current zoom lenses for compact digital cameras face challenges in achieving a high zoom ratio while maintaining a compact structure and suppressing aberrations, particularly in designs with a large aperture and high magnification, where the existing configurations often result in increased lens diameter and aberration issues.

Innovation Solution

A zoom lens configuration comprising a first lens unit with positive refractive power, a second lens unit with negative refractive power, and a third lens unit with positive refractive power, where the third lens unit includes cemented lenses with specific refractive index and focal length ratios, and air spaces, satisfying conditional expressions to control aberrations and maintain a compact structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a zoom lens with large aperture and high magnification is designed, then the lens can capture images in dark places and increase shutter speed, but the lens diameter increases and aberration issues worsen

Engineering Contradiction:

Improvelens apertureVSAvoidaberration

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The third lens unit is divided into multiple lens components with different refractive powers (positive and negative). This segmentation allows for better control of light paths and aberration correction while maintaining a large aperture, resolving the contradiction between illumination intensity and aberration control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different lens components within the third lens unit have different refractive indices and focal lengths tailored to specific regions of the optical path. This local optimization enables effective aberration correction in high-magnification regions while maintaining large aperture for good illumination.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If a zoom lens with high zoom ratio is designed, then the magnification capability increases, but the lens structure becomes more complex and size increases

Engineering Contradiction:

Improvezoom ratioVSAvoidlens structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The third lens unit serves multiple functions simultaneously: it provides the necessary magnification for high zoom ratio while also acting as an aberration correction unit. The cemented lens structure within this unit performs both focusing and aberration control, reducing overall system complexity despite high zoom requirements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cemented lens structure embeds one lens element within another, with the positive and negative lenses integrated in a compact arrangement. This nesting achieves high magnification capability while maintaining a compact structure and reducing overall complexity.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Volume of moving object

If a compact lens structure is maintained, then the camera size is reduced for portability, but aberration control becomes more difficult

Engineering Contradiction:

Improvelens sizeVSAvoidaberration

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The cemented lens structure employs asymmetric design with different refractive indices (nd3_2p ≥ 1.8 and nd3_2n ≥ 2.0) and specific focal length ratios. This asymmetric configuration enables effective aberration correction in a compact form factor, resolving the contradiction between compact size and aberration control.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention uses specific parameter ranges for refractive indices and focal lengths to optimize the balance between compact size and aberration control. By carefully selecting parameters within defined ranges, the lens achieves both compact dimensions and effective aberration suppression.

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

This configuration allows for a high zoom ratio while suppressing aberrations and maintaining a compact lens structure, enabling efficient image capture with a large aperture and high magnification, thus addressing the limitations of existing designs.

Implementation Method 1

a second lens component having a negative refractive power in which, a lens having a positive refractive power and a lens having a negative refractive power are cemented

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10139605B2Zoom lens and image pickup apparatus using the same

Publication Date: 2018.11.27 OM DIGITAL SOLUTIONS CORP

AI summary

A zoom lens comprises in order from an object side,a first lens unit having a positive refractive power,a second lens unit having a negative refractive power, anda third lens unit having a positive refractive power, andthe third unit having a positive refractive power comprises in order from the object side,a first lens component having a positive refractive power, anda second lens component having a negative refractive power in which, a lens having a positive refractive power and a lens having a negative refractive power are cemented, andthe zoom lens satisfies the following conditional expressions (1), (2), and (3)1.4<|f3_2p/f3_2n|<2.6 (1)nd3_2p−nd3_2n≥0 (2)nd3_2n≥1.8 (3).