Zoom Lens Configuration for Large-Format Imaging

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Solution Overview

Problem

Existing zoom lenses with high magnification and high performance become oversized when adapted for large-format image pickup devices, as they are optimized for smaller formats and struggle to maintain compactness and lightweight design while achieving high optical performance across the entire zoom and focus range.

Innovation Solution

A zoom lens configuration comprising a front lens unit with positive refractive power that does not move during zooming, one or two intermediate lens units with negative refractive power that move for zooming, a first rear lens unit with negative refractive power that moves, a second rear lens unit with positive refractive power that moves, and a third rear lens unit with positive refractive power that does not move, where all intervals between adjacent lens units change for zooming, satisfying specific focal length ratios to suppress aberrations and maintain compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a zoom lens is optimized for high magnification and high performance with a configuration suitable for small image pickup devices, then optical performance and compactness are improved, but the lens becomes oversized when adapted for large-format image pickup devices

Engineering Contradiction:

Improveoptical performanceVSAvoidlens size

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The zoom lens is divided into five distinct lens units (front lens unit, intermediate lens units, first rear lens unit, second rear lens unit, third rear lens unit) with specific refractive powers and movement characteristics. This segmentation allows each unit to be optimized independently for its function while maintaining overall compactness and high optical performance when adapted for large-format image pickup devices

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies specific conditional expressions for focal length ratios (−6≤f1/f2≤−2.5, 2.8≤ft/f1≤5.0, 3.5≤f3/f2≤12.0) and defines precise movement intervals between lens units during zooming. These parameter changes enable the lens to maintain high magnification and optical performance while controlling the overall size when adapted for large-format image pickup devices

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the lens configuration is changed to accommodate large-format image pickup devices, then adaptability is improved, but compactness and lightweight design are compromised

Engineering Contradiction:

Improveadaptability to large-format devicesVSAvoidlens weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The intermediate lens units and rear lens units are designed to move during zooming operations, with specific movement intervals defined between adjacent lens units. This dynamic configuration allows the lens to achieve high magnification and adapt to large-format image pickup devices while maintaining a compact and lightweight design by optimizing the movement paths and ranges of individual lens units

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If multiple lens units are configured to move during zooming to achieve high magnification, then optical performance is improved, but device complexity increases

Engineering Contradiction:

Improveoptical performanceVSAvoidlens structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The zoom lens is divided into five distinct lens units with specific refractive powers and movement characteristics. This segmentation allows each unit to be optimized independently for its function while maintaining overall compactness and high optical performance

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The front lens unit serves dual functions: it acts as the first lens unit for focusing operations and provides the positive refractive power necessary for the overall lens configuration. This multi-functionality reduces the need for additional separate components, thereby managing complexity while maintaining high optical performance

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 magnification, compactness, and lightweight design while maintaining high optical performance across the zoom range, effectively addressing the issue of lens enlargement when adapted for large-format image pickup devices.