Screw-Fixed Lens Unit for Waterproof Camera Serviceability
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Solution Overview
Problem
Existing lens units that fix lenses to holders using resin claws or projections face issues with lens detachment and waterproof performance due to the need to damage the claw for removal and the repulsive force of O-rings causing lens float, which degrades waterproofing.
Innovation Solution
A lens unit design that fixes lenses to a holder using a screw structure, with separate optical and radial direction positioning parts, and optionally adhesive bonding, allowing easy detachment and preventing lens float.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a claw or projection made of resin is deformed by heat to fix a lens to a lens holder, then the lens can be firmly fixed, but the lens cannot be detached without damaging the claw or projection
Solution Approach 1:
The fixing structure is divided into a screw portion formed on the lens and a screw hole in the lens holder, allowing the lens to be securely fixed during use but easily detached by simply unscrewing, without damaging either component. This segmentation enables reversible fixing while maintaining strong attachment during operation.
2Strength
If the lens is fixed by deforming a resin claw by heat, then the lens is firmly attached, but the lens may float due to repulsive force of the O-ring during cooling, degrading waterproof performance
Solution Approach 1:
The screw structure is designed to pre-compress the O-ring between the lens and lens holder before the lens cools and contracts. This preliminary compression action ensures the O-ring remains effectively sealed even when thermal contraction creates gaps, preventing water infiltration while maintaining firm attachment.
3Ease of repair
If a screw structure is used to fix the lens, then the lens can be easily detached for maintenance, but additional components increase device complexity
Solution Approach 1:
The screw portion is directly formed on the lens itself, merging the fixing mechanism with the lens structure. This eliminates the need for separate fixing components, reducing overall device complexity while maintaining ease of lens detachment and reattachment for maintenance purposes.
4Ease of operation
If play is provided in the screw structure to enable smooth threading, then the screw can be easily engaged, but rattling of the lens in the optical axis direction occurs causing position disturbance
Solution Approach 1:
The fixing structure is segmented into three functional zones: a screw portion for easy engagement and detachment, a positioning portion that eliminates optical axis play to ensure precise lens positioning, and a sealing portion with the O-ring for waterproofing. This segmentation allows each zone to optimize its specific function without compromising others.
Solution Approach 2:
The positioning portion acts as an intermediary between the screw portion and the lens optical surface, preventing the transmission of rattling and position disturbances from the screw engagement to the lens optical positioning, thereby maintaining manufacturing precision while enabling easy operation.
Data Source
AI summary
A lens unit in a camera unit includes a first lens which is a lens, a lens holder in a tube shape which holds the first lens, and an O-ring which is a seal member. The first lens is fixed to the lens holder using a screw structure. The O-ring is sandwiched between the first lens and the lens holder in the optical axis direction,