Lens Barrel Focus Lens Group Segmentation

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Solution Overview

Problem

Conventional lens barrels with inner focus type mechanisms face challenges in maintaining focus when object distance changes during zooming, leading to potential defocus issues due to the movement of focus lenses with other lens groups during zooming operations.

Innovation Solution

The design incorporates a rotary barrel with cam grooves that allow independent movement of the focus lens group in the optical axis direction, using cam followers and actuators to adjust the focus lens position separately from other lens groups, thereby minimizing defocus and enhancing optical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the focus lens is moved together with other lens groups during zooming, then the zooming operation is simplified, but the focus accuracy deteriorates due to object distance changes

Engineering Contradiction:

Improvezooming operationVSAvoidfocus accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The lens barrel is divided into separate functional units: a first lens group for zooming operations and a focus lens group for focus control. The focus lens group is held by a dedicated focus lens holding frame that can move independently from the first lens group, allowing zooming without affecting focus position. This segmentation enables independent control of zooming and focusing functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The focus lens is extracted from the common lens group structure and placed in a separate focus lens holding frame. This extraction allows the focus lens to be controlled independently from other lens groups during zooming operations, preventing focus shift while maintaining simplified zooming mechanics.

Inventive Principle:

Principle #2Taking out (Extraction)

2Measurement precision

If the focus lens position is adjusted independently during zooming, then focus accuracy is improved, but the device complexity increases

Engineering Contradiction:

Improvefocus accuracyVSAvoidlens barrel structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The focus lens holding frame integrates multiple functions: it holds the focus lens, provides a cam follower for controlled movement, and interfaces with both the first lens group and the second lens group. By merging these functions into a single component, the design achieves independent focus control without proportionally increasing overall structural complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The focus lens holding frame acts as an intermediary component between the first lens group (for zooming) and the second lens group (for focus adjustment). This intermediary structure enables coordinated movement where the cam follower engages with cam grooves to translate zooming motion into precise focus lens positioning without requiring complex direct coupling mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11320627B2Lens barrel and imaging device

Publication Date: 2022.05.03 NIKON CORP

AI summary

A lens barrel including a first lens, an actuator that drives the first lens, a first barrel that holds a first cam follower and the actuator and moves in an optical axis direction, a second lens, and a second barrel that holds a second cam follower and the second lens and moves in the optical axis direction, the second barrel having a first hole portion in which the first cam follower is disposed.