Night Vision Eyepiece With Lightweight Integrated Lens Cell
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Solution Overview
Problem
Existing night vision goggles are heavy due to multiple components, including glass lenses and metal parts, leading to physiological strain, misalignment of optical components, and increased cost, with prior solutions exacerbating these issues through additional mechanical features and loose tolerances.
Innovation Solution
A lightweight all-plastic lens cell assembly with integrated sealing features, focus stops, and focus thread grooves, featuring an interference fit for lens elements to eliminate centering and tilt errors, and integral spacers for improved collimation and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass lenses and metal parts are used in the eyepiece assembly, then optical performance and durability are improved, but weight increases significantly
Solution Approach 1:
The patent changes the material parameters from traditional glass and metal to plastic materials, specifically using plastics with appropriate refractive indices and mechanical properties. This parameter change maintains optical performance while significantly reducing density and weight of the lens elements and housing.
Solution Approach 2:
The patent employs composite material strategies by integrating multiple plastic components with different properties into the eyepiece assembly. The lens elements, housing, and spacers are all made from engineered plastic materials that combine optical clarity with mechanical strength, replacing traditional glass-metal composites.
2Ease of manufacture
If traditional lens cell assembly with clearance fits is used, then manufacturing is easier, but collimation errors and centering errors increase
Solution Approach 1:
The patent merges the lens element and spacer into a single integrated plastic component, eliminating the separate spacer piece. This integration removes the clearance fit between lens and spacer, thereby eliminating centering errors and tilt errors while maintaining ease of manufacture through one-step molding processes.
Solution Approach 2:
The integrated spacer structure acts as an intermediary that precisely positions the lens element within the housing. By making the spacer integral to the lens element rather than a separate part, it serves as a built-in positioning mechanism that eliminates alignment errors without requiring additional adjustment mechanisms.
3Strength
If press fitting is used to secure lens elements in metal lens cells, then mechanical strength is improved, but stress-induced chipping and optical distortion increase
Solution Approach 1:
The patent changes the material parameters from metal to plastic for both the lens cell and lens elements. Plastic materials have lower elastic moduli and can accommodate thermal expansion differences, reducing stress concentrations at interfaces. This parameter change eliminates the chipping problem while maintaining adequate mechanical strength through material selection and design.
Solution Approach 2:
The patent applies local quality by designing the plastic lens element with specific geometric features at the interface regions, such as rounded edges and optimized thickness distributions. These local modifications reduce stress concentration points where chipping would occur, while the overall component maintains sufficient strength.
4Ease of manufacture
If lens elements are made with larger diameters to accommodate clearance fits, then manufacturing tolerances are easier to meet, but weight and collimation errors increase
Solution Approach 1:
The patent combines the lens element and spacer functions into a single molded plastic part. This integration eliminates the need for clearance fits between separate components, allowing the use of smaller, optimized lens diameters that reduce weight while maintaining manufacturing feasibility through precise one-step molding processes.
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present invention is a lightweight lens cell assembly forming a nightvision eyepiece. The lens cell has an integral focusing mechanism and at least one lens element manufactured from a polymer. Because the lens cell is manufactured from a material thermally matched to the polymer and the lens element is integrally connected to the lens cell or connected to the lens cell by an interference fit, the assembly provides significant benefits to both weight and error reduction.