Lens Barrel Eccentricity Stabilization via Asymmetric Leaf Spring Biasing
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Solution Overview
Problem
Conventional lens apparatuses face instability in optical performance due to changes in the eccentricity state of the rotatable barrel relative to the fixed barrel, caused by varying fitting play and external disturbances, which affects the alignment and biasing forces of elastic members.
Innovation Solution
A lens apparatus with a fixed barrel and a movable cam ring, where leaf springs are attached to the outer surface of the fixed barrel, biasing the cam ring through bore formations, reducing play and maintaining stability by orienting biasing forces in a direction that counters gravity and minimizes pitch movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastic members are retained between the rotatable barrel and the fixed barrel to reduce fitting play, then the fitting play is reduced, but the displacement amount of the elastic member must be small due to space constraints, requiring large rigidity which causes biasing force variation
Solution Approach 1:
The elastic member is configured to extend in the axial direction of the rotatable barrel rather than radially between the barrels. This dimensional change allows the elastic member to achieve large displacement amounts along the axis while maintaining compact radial dimensions, enabling use of lower rigidity materials with consistent biasing forces.
Solution Approach 2:
The elastic member is divided into multiple segments along its length, with each segment capable of independent deformation. This segmentation allows the elastic member to accumulate large total displacement through sequential segment deformation, reducing the need for high rigidity while maintaining stability.
2Stability of the object's composition
If elastic members are provided at equal intervals in the circumferential direction, then the rotatable barrel is centered on the optical axis, but the position becomes unstable under operating load changes or external disturbances
Solution Approach 1:
The elastic member is positioned asymmetrically relative to the optical axis, with its projection overlapping the optical axis only in specific angular ranges during operation. This asymmetric configuration creates a unidirectional biasing effect that actively counteracts gravitational and external disturbance forces, providing stable positioning under load variations.
Solution Approach 2:
The elastic member is pre-configured to generate biasing forces that anticipate and counteract gravitational forces and external disturbances before they cause position drift. The asymmetric positioning ensures the biasing force always acts to restore the rotatable barrel to its correct angular position.
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 stabilizes the position of the rotatable barrel, reduces optical performance variations, and allows for larger displacement of elastic members, enhancing the precision and stability of the lens apparatus while reducing the apparatus's size.
Implementation Method 1
a second barrel fitted to an inside of the first barrel and configured to be moved relative to the first barrel; and an elastic member fixed to an outer surface of the first barrel, and biasing an outer surface of the second barrel to an inner surface of the first barrel
Data Source
AI summary
A lens apparatus of the present invention includes: a first barrel configured not to be moved; a second barrel fitted to an inside of the first barrel and configured to be moved relative to the first barrel; and an elastic member fixed to an outer surface of the first barrel, and biasing an outer surface of the second barrel to an inner surface of the first barrel through a bore formed in the first barrel.