Retractable Lens Barrel Teleconverter Interference Prevention
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Solution Overview
Problem
Conventional zoom lens barrels face issues with interference between teleconverter components and the lens frame when a teleconverter is mounted, leading to potential damage and performance degradation.
Innovation Solution
A lens barrel design featuring a lens drive frame driven by three cam pins, with a retractable lens frame and a biasing member that expands and contracts to retract the lens frame when a teleconverter is mounted, preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a teleconverter is mounted between the camera body and lens barrel, then the focal length is extended, but the members on the teleconverter side interfere with the lens frame on the lens barrel side in the optical axis direction, causing potential damage to parts
Solution Approach 1:
The lens frame is designed to be movable along the optical axis rather than fixed. A biasing member (spring) provides a restoring force that enables the lens frame to dynamically adjust its position. When a teleconverter is mounted, the lens frame automatically moves in the optical axis direction to avoid interference, and the spring ensures it returns to its original position when the teleconverter is removed.
Solution Approach 2:
A biasing member (compression spring) is introduced as an intermediary element between the lens frame and the lens drive frame. This spring acts as a mediator that provides the necessary force to move the lens frame away from the interference zone when a teleconverter is present, while maintaining normal operation when no teleconverter is mounted.
2Reliability
If the lens frame is made movable to prevent interference with teleconverter, then part damage is prevented, but the structural complexity increases with additional components like biasing members and guide shafts
Solution Approach 1:
The lens drive frame serves multiple functions: it drives the lens frame during normal focusing operations and simultaneously acts as a guide structure (with guide shafts) to constrain the lens frame's movement when a teleconverter is mounted. The biasing member provides both the force to move the lens frame away from interference and the restoring force to return it to position.
Solution Approach 2:
The lens frame is nested within the lens drive frame, with the lens frame movable along guide shafts that are part of the lens drive frame structure. This nested arrangement allows the smaller lens frame to move independently within the larger lens drive frame structure, enabling the protection mechanism without requiring a completely separate system.
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 design effectively prevents damage and interference issues when a teleconverter is mounted, ensuring reliable operation and maintaining optical performance.
Implementation Method 1
a biasing member that is attached along the guide shafts, applies a biasing force for biasing the retractable lens frame toward the pressing member in the optical axis direction, and expands and contracts when the teleconverter is mounted to the mounting portion, thereby retracting the retractable lens frame toward the subject side in the optical axis direction
Data Source
AI summary
A lens barrel (10) comprises a lens mount unit (20a), a retractable lens frame (18b), a seventh lens group unit (18), three cam pins (18ad), guide shafts (18af), a pressing member (18d), and a compression spring (18ag). At least two of the guide shafts (18af) are provided to the seventh group unit (18) and are disposed in the optical axis (X). The compression spring (18ag) applies a biasing force that biases the retractable lens frame (18b) against the pressing member (18d) in the optical axis (X) direction, and expands and contracts when a teleconverter (30) is mounted to the lens mount unit (20a), causing the retractable lens frame (18b) to retract to the subject side in the optical axis (X) direction.