Optical System Lens Barrel Contact Design for Thermal Stability
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Solution Overview
Problem
In optical systems, the space between lenses and the lens barrel can cause decentering and tilting of lenses, leading to aberrations and reduced optical performance, especially at low temperatures due to thermal expansion differences.
Innovation Solution
The optical system includes a configuration with cemented lenses and interval holding members, where the lenses are in contact outside their effective regions, satisfying specific diameter ratios and thermal expansion coefficient differences to minimize decentering and tilting, and includes aspheric surfaces to correct aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If space is provided between lenses and lens barrel to accommodate thermal expansion, then reliability under temperature variations is improved, but lens decentering and tilting occur causing aberrations
Solution Approach 1:
The patent applies local quality by making different parts of the lens serve different functions: the effective region (central area) maintains optical quality for imaging, while the peripheral region (outside effective region) makes contact with the lens barrel to provide mechanical support and positioning. This localized functional differentiation allows the lens to simultaneously achieve optical performance and positional stability without requiring large clearance for thermal expansion.
Solution Approach 2:
The patent implements preliminary anti-action by designing the lens peripheral region to make contact with the lens barrel before thermal expansion occurs. This pre-established contact structure prevents decentering and tilting that would otherwise occur during temperature variations, counteracting the harmful effects of thermal expansion before they can degrade optical performance.
2Device complexity
If lenses are made cemented to reduce elements, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies merging by combining multiple lens elements into cemented lens units (e.g., cemented lenses 105 and 106). This reduces the total number of separate lens elements and air-glass interfaces in the optical system, simplifying the overall device complexity while maintaining optical performance through precise cementing of the combined elements.
3Manufacturing precision
If aspheric surfaces are added to correct aberrations, then optical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies spheroidality by incorporating aspheric surfaces on specific lens surfaces (e.g., object-side surface of first negative lens, image-side surface of final positive lens). These aspheric curvatures effectively correct spherical aberration and other optical imperfections, improving image quality. The aspheric shapes are strategically placed on only critical surfaces rather than all lenses, balancing aberration correction with manufacturing feasibility.
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 configuration reduces lens decentering and tilting, enhances optical performance by correcting aberrations, and allows for a compact design with minimal space between the lens barrel and lenses, maintaining favorable optical properties across temperature variations.
Implementation Method 1
the space between lenses and the lens barrel can cause decentering and tilting of lenses, leading to aberrations and reduced optical performance, especially at low temperatures due to thermal expansion differences
Data Source
AI summary
An optical system includes a first lens and a second lens, at least one of which is a cemented lens. Outside respective effective regions of the first lens and the second lens, the first lens and the second lens are in contact with a lens or an interval holding member disposed between the first lens and the second lens. Following inequalities are satisfied:0.96<D1/D2<1.04, and0.96<D1/D3<1.04, where maximum diameters of the first lens and the second lens are D1 and D2, respectively, and a maximum diameter of the lens or the interval holding member is D3.