Wide-Angle Imaging Lens With Movable Front Group Focusing

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Solution Overview

Problem

Existing imaging lenses face challenges in achieving a wide angle, small size, and favorable optical performance, particularly in correcting aberrations and maintaining compactness while ensuring high optical quality.

Innovation Solution

The imaging lens design consists of a front group and a rear group with specific refractive powers, where at least one group moves during focusing, and includes lenses with optimized curvature and refractive indices to satisfy conditional expressions, ensuring a wide angle and small size with improved optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the lens system is designed to achieve a wide angle, then the angle of view is improved, but the lens size and complexity increase

Engineering Contradiction:

Improveangle of viewVSAvoidlens structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The lens system is divided into distinct groups: a front group containing negative meniscus lenses and other elements, a stop, and a rear group with positive refractive power. This segmentation allows each group to be optimized independently for wide-angle performance while managing overall system complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The front group is designed to move during focusing operations while the rear group remains stationary relative to the image plane. This dynamic configuration enables wide-angle coverage with flexible focusing capability without requiring the entire lens system to be complex and movable.

Inventive Principle:

Principle #15Dynamics

2Length of moving object

If the lens system is compacted to reduce size, then the lens length is reduced, but optical performance and aberration correction deteriorate

Engineering Contradiction:

Improvelens lengthVSAvoidoptical performance

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent specifies precise parameter ranges including Conditional Expression (1) for the ratio of lens length to focal length, Conditional Expression (2) for the back focal length ratio, and Conditional Expression (3) for the angle of view. These parameter optimizations enable compact lens length while maintaining optical performance through mathematically constrained design space.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The lens system employs multiple lens materials with different refractive powers and dispersion characteristics. The front group uses negative meniscus lenses with specific curvature radii ratios, combined with other lens types, creating a composite optical system that achieves compact size while correcting aberrations through material diversity.

Inventive Principle:

Principle #40Composite materials

3Reliability

If multiple lenses are added to correct aberrations, then optical performance is improved, but the lens size and weight increase

Engineering Contradiction:

Improveaberration correctionVSAvoidlens weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

Specific lens elements within the front group are designed with particular properties: negative meniscus lenses with convex surfaces facing the object side, and specific curvature radius ratios. This local optimization of individual elements achieves aberration correction without requiring excessive numbers of lenses, thereby controlling weight.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The front group moves during focusing while the rear group stays stationary. This dynamic arrangement allows aberration correction through the movement of fewer elements rather than requiring all lenses to be heavy and precisely positioned, reducing overall weight while maintaining optical performance.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If the front group moves during focusing, then focusing capability is improved, but the complexity of the moving mechanism increases

Engineering Contradiction:

Improvefocusing capabilityVSAvoidfocusing mechanism complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The lens system is segmented into a movable front group and a stationary rear group. This segmentation simplifies the focusing mechanism by requiring movement of only the front group elements rather than the entire lens system, reducing mechanical complexity while maintaining full focusing capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inventive Principle:

Principle #15Dynamics

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 lens design achieves a wide angle, small size, and favorable optical performance by effectively correcting aberrations and maintaining compactness, while allowing for reduced weight and size in imaging apparatuses.

Implementation Method 1

an imaging lens consisting of, in order from an object side to an image side: a front group; a stop; and a rear group that has a positive refractive power

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12443007B2Imaging lens and imaging apparatus

Publication Date: 2025.10.14 FUJIFILM CORP

AI summary

An imaging lens consisting of, in order from an object side to an image side: a front group; a stop; and a rear group that has a positive refractive power. The imaging lens satisfies predetermined conditional expressions.