Open Cell Foam Dust Seal for AR Camera Cavity
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Solution Overview
Problem
Augmented reality viewing devices face challenges in maintaining a dust-free environment within their optical components, particularly due to manufacturing tolerances that result in varying gaps between sub-assemblies, leading to potential image quality degradation from stress-induced deformations and dust infiltration.
Innovation Solution
The implementation of a viewing device design featuring a shell piece with a transparent window and internal mounting structure, utilizing a seal system with open cell foam seal members that provide continuous contact and a closed front cavity to prevent dust entry, while being compressible to accommodate manufacturing variance and reduce stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manufacturing tolerances are tight to reduce gaps between sub-assemblies, then image quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The seal member is designed with specific material properties (compressibility) and geometric parameters (thickness, cross-sectional area) that allow it to adapt to gap variations within a range without requiring tight manufacturing tolerances. This transforms the solution from controlling gap dimensions to controlling seal member properties.
Solution Approach 2:
The seal member acts as a pre-designed cushioning element that anticipates and compensates for potential gap variations. By designing the seal with specific compressible properties, the system is pre-prepared to handle manufacturing tolerances without requiring additional adjustment or complex assembly procedures.
2Object-affected harmful factors
If gaps between sub-assemblies are reduced to prevent dust infiltration, then dust seal performance is improved, but stress on optical components increases
Solution Approach 1:
The seal member is designed as a flexible, compressible element that can deform to accommodate gap variations. This flexibility allows the seal to maintain contact and prevent dust infiltration while absorbing mechanical stresses without transmitting them to the optical components.
Solution Approach 2:
The seal member serves as a pre-designed stress-absorbing element that protects optical components from stress-induced deformations. By positioning the seal to bear mechanical loads, the system pre-protects sensitive components while maintaining dust seal integrity.
3Ease of manufacture
If seal members are made compressible to accommodate manufacturing variance, then ease of assembly is improved, but seal effectiveness may be compromised
Solution Approach 1:
The seal member's compressibility is precisely controlled through material selection and geometric design. By optimizing parameters such as material durometer, cross-sectional area, and thickness, the seal achieves the right balance between ease of assembly (ability to compress to fill gaps) and seal effectiveness (maintaining sufficient contact pressure).
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 seals the optical components, maintaining image quality by preventing dust infiltration and minimizing stress on sensitive components, even with manufacturing tolerances that result in varying gaps, ensuring a stable and clear visual experience.
Implementation Method 1
utilizing a seal system with open cell foam seal members that provide continuous contact and a closed front cavity to prevent dust entry, while being compressible to accommodate manufacturing variance and reduce stress on components
Data Source
AI summary
An open cell foam is used to create a seal between a camera and a shell piece. The shell piece, camera, seal and a transparent window form a closed front cavity. Because the cavity is closed, dust can remain away from a lens of the camera.