Optical Apparatus Mechanical Sealing Against Dew Condensation
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Solution Overview
Problem
Dew condensation on eyepiece lenses due to temperature changes and moisture entry, leading to degraded visibility and image quality, particularly when plastic materials are used, as they are prone to deformation from adhesive shrinkage.
Innovation Solution
A sealing structure with a first and second optical member held by a first and second holding member, sealed by first and second sealing members, preventing moisture entry and maintaining optical accuracy by using a convex lens and elastic members to stabilize positions and reduce air layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adhesive medium is used to seal the space between optical members, then moisture entry is prevented, but surface accuracy and image quality deteriorate due to adhesive shrinkage
Solution Approach 1:
The adhesive medium is extracted from the sealing function and replaced by a mechanical sealing structure consisting of grooves and sealing members. This eliminates the harmful shrinkage effect while maintaining the moisture barrier function.
Solution Approach 2:
A sealing member (such as an O-ring or gasket) is introduced as an intermediary element between the grooves and the moisture. This sealing member provides effective moisture barrier without causing deformation to the optical members.
2Ease of manufacture
If plastic material is used for eyepiece lenses, then manufacturing cost and weight are reduced, but surface accuracy and image quality worsen due to deformation from adhesive shrinkage
Solution Approach 1:
The adhesive bonding method is replaced with a mechanical sealing approach using grooves and sealing members. This eliminates the shrinkage force that deforms plastic lenses while maintaining the sealing function.
Solution Approach 2:
The joining method is changed from chemical bonding (adhesive) to mechanical sealing (grooves + sealing member). This parameter change eliminates the harmful side effect of shrinkage while maintaining the benefits of plastic lens materials.
3Reliability
If adhesive bonding is used to seal optical members, then moisture entry is prevented, but device complexity increases due to additional bonding processes
Solution Approach 1:
The holding structure and sealing structure are merged into a single integrated design. The grooves are formed as part of the holding member structure, and the sealing members are positioned within these grooves, combining multiple functions into one cohesive system.
Data Source
AI summary
An optical apparatus includes a first optical member and a first holding member configured to hold the first optical member and a second optical member located on an inner side of the first optical member that are sealed with a first sealing member A space between the first optical member and the second optical member is sealed.