Lens Apparatus Rotation Restriction and Elastic Fixation
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Solution Overview
Problem
Existing lens fixation methods, such as thermal caulking or adhesives, can cause stress-induced distortion of lens surfaces, and methods using elastic members can result in high pressing forces and instability, leading to rotation of lenses about the optical axis and degradation of optical performance.
Innovation Solution
A lens apparatus featuring a holding barrel and a rotation restriction member made of fiberglass-reinforced polycarbonate resin, which abuts the holding barrel to restrict rotation about the optical axis while using tension coil springs to apply a weak biasing force, reducing distortion and ensuring accurate positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a lens is fixed via an elastic member in a narrow slit between the pressing member and the lens, then the lens can be pressed against the lens holder, but the spring constant of the elastic member becomes extremely high, resulting in an extremely high pressing force that deforms the lens surface
Solution Approach 1:
The patent changes the geometric parameters of the elastic member, specifically increasing the slit width from a narrow configuration to a width of 0.5-2.0 mm. This parameter change reduces the spring constant of the elastic member, thereby reducing the pressing force applied to the lens while maintaining adequate fixation. The pressing force is controlled to be 1/10 to 1/5 of the lens weight, preventing lens surface deformation.
Solution Approach 2:
The patent introduces a pressing member as an intermediary component between the lens holder and the lens. This pressing member, equipped with the elastic member, mediates the force transmission and allows for controlled application of pressing force. The pressing member includes a pressing surface that contacts the lens, distributing the force evenly and preventing localized deformation.
2Manufacturing precision
If a lens is fixed with a weak force to reduce distortion of the lens surface, then lens surface accuracy is maintained, but it becomes difficult to stably press each individual lens with the same force
Solution Approach 1:
The patent designs the elastic member with universal geometric parameters (slit width of 0.5-2.0 mm) that can be applied to lenses of different masses and sizes. The standardized design ensures consistent pressing force characteristics across different lens types. The pressing member also provides multiple functions: fixation, positioning, and force distribution, ensuring reliable and stable fixation for each individual lens.
Solution Approach 2:
The patent optimizes the elastic member parameters (slit width, material properties) to achieve a spring constant that provides sufficient fixation force while maintaining lens surface accuracy. The pressing force is precisely controlled to be 1/10 to 1/5 of the lens weight, ensuring both stability and prevention of deformation across different lens specimens.
3Strength
If thermal caulking or adhesive is used for fixing a lens to a lens holding barrel, then the lens can be securely fixed, but stress generated during fixing causes distortion of the lens surface
Solution Approach 1:
The patent replaces thermal caulking and adhesive methods with a mechanical fixation system using an elastic member. This substitution eliminates the need for thermal or chemical fixation processes that generate stress and cause lens surface distortion. The mechanical spring-based system provides secure fixation through controlled elastic force without applying stress to the lens.
4Reliability
If a lens placed closest to an object is fixed using an elastic member, then the lens can be held in position, but the lens rotates about the optical axis when external rotational force is applied, causing change in optical performance
Solution Approach 1:
The patent introduces asymmetry in the form of a rotation prevention protrusion that extends in the axial direction. This asymmetric feature engages with a corresponding structure to prevent rotational movement of the lens about the optical axis. The asymmetric design specifically addresses the rotation problem while maintaining the symmetric elastic fixation for positioning.
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
The solution effectively suppresses lens rotation and distortion, maintaining optical performance and allowing for stable, accurate lens positioning without degrading the lens's surface accuracy or requiring complex tools for assembly.
Implementation Method 1
by intervention of the pressing member formed of a ring-shaped elastically-deformable elastic material
Implementation Method 2
tension coil springs to apply a weak biasing force
Implementation Method 3
the rotation restriction member is configured to come into abutment against the holding barrel along a direction of rotation of the optical member about an optical axis, to restrict the rotation
Data Source
AI summary
Provided is a lens apparatus including: an optical member; a holding barrel holding the optical member, and a rotation restriction member fixed to the optical member, wherein the rotation restriction member is configured to come into abutment against the holding barrel along a direction of rotation of the optical member about an optical axis, to restrict the rotation of the optical member about the optical axis, relative to the holding barrel, and lacks contact with the holding barrel along an optical-axis direction and a radial direction of the optical member.