Nested Lens Barrel Layout for Low-Force Focus Lens Drive
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Solution Overview
Problem
Conventional stepping motors used in focus lens drive mechanisms have a small driving force, making it difficult to move heavy focus lenses in the optical axis direction.
Innovation Solution
A lens barrel design that includes a first lens holding frame and a second lens holding frame, each with its own driving unit, allowing for the movement of lenses in the optical axis direction, and utilizing a stepping motor to drive these frames, thereby distributing the weight and enabling effective lens movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single heavy focus lens is used, then the lens can provide sufficient optical performance, but the driving force required to move it becomes excessively large
Solution Approach 1:
The patent divides the focus lens system into multiple separate focus lenses (first focus lens and second focus lens) that can be independently driven. Each lens is mounted on its own holding frame with dedicated driving units, allowing the total weight to be distributed across multiple smaller driving forces rather than requiring a single large driving force to move one heavy lens.
2Device complexity
If a single driving unit is used for one focus lens, then the structure is simple, but the driving force is insufficient to move heavy lenses
Solution Approach 1:
The patent implements multiple driving units (first driving unit and second driving unit) corresponding to multiple focus lenses. Each driving unit is responsible for moving its respective focus lens independently, distributing the mechanical load and enabling sufficient driving force for each lens while maintaining manageable structural complexity through modular design.
Solution Approach 2:
The patent arranges the lens holding frames and driving units in a nested configuration where the first lens holding frame is positioned inside the second lens holding frame. This nested arrangement allows multiple driving units to be compactly integrated within a shared structural framework, reducing overall device complexity while maintaining the benefits of multiple independent driving units.
3Weight of moving object
If multiple focus lenses are used, then the total weight increases, but the driving force per lens decreases making movement easier
Solution Approach 1:
The patent segments the focus lens system into multiple independently driven units, each with its own driving unit. This segmentation allows the total weight of multiple lenses to be managed by distributing the driving force across multiple independent actuators, where each actuator handles a smaller portion of the total weight, making movement feasible and controllable.
Data Source
AI summary
A lightweight lens barrel that includes two focus lenses. The first lens holding frame for holding a first lens L5, a first drive unit STM5 for causing the first lens holding frame to move in the optical axis direction, a second lens holding frame for holding a second lens L6, and a second drive unit STM6 for causing the second lens holding frame to move in the optical axis direction, the first lens holding frame being arranged on an inner peripheral side of the second lens holding frame.