Optical Lens Design for Compact Confocal Imaging
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Solution Overview
Problem
Existing optical lenses face challenges in achieving low-profile and compact designs, wide viewing angles, high resolution, and 24-hours confocal image-capturing capability while maintaining low fabrication costs and minimizing thermal drift, as they often require multiple lenses or switch mechanisms, which increase costs and can be affected by thermal drift from plastic materials.
Innovation Solution
The optical lens design consists of a first glass lens with negative refractive power and a second lens group with positive refractive power, including one glass lens and two plastic lenses, arranged to satisfy specific refractive power conditions and include an aperture stop, achieving low-profile and compact designs, wide viewing angles, high resolution, and reduced distortion with minimal thermal drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a typical optical lens uses a considerable number of lenses or a switch mechanism for an optical filter to achieve 24-hours confocal capability, then the confocal image-capturing capability is improved, but the fabrication cost increases
Solution Approach 1:
The optical lens achieves 24-hours confocal capability through a single integrated lens design that functions for both day and night imaging without requiring additional lenses or switch mechanisms. The lens structure combines multiple functional elements (including plastic and glass lenses with specific refractive powers) into one universal component that maintains confocal performance across different lighting conditions, thereby eliminating the need for costly additional components while preserving the confocal image-capturing capability
Solution Approach 2:
The patent merges multiple lens elements with different materials and refractive powers into a single integrated optical lens assembly. By combining plastic lenses (for cost-effectiveness and moldability) with glass lenses (for optical precision and thermal stability) in specific configurations, the design achieves confocal capability for both visible and infrared wavelengths without requiring separate lenses or switching mechanisms, thus reducing fabrication costs while maintaining reliability
2Ease of manufacture
If plastic lenses are used to reduce fabrication costs, then the ease of manufacture is improved, but thermal drift occurs that lowers optical performance
Solution Approach 1:
The optical lens employs a composite structure combining plastic lenses and glass lenses with specific refractive powers. The plastic lenses (with refractive powers of -1.5 to -2.5 and +1.0 to +2.0) provide cost-effective molding and design flexibility, while the glass lens (with refractive power of +3.0 to +4.0 and Abbe number >60) provides thermal stability and optical precision. This composite material approach allows the system to achieve both low fabrication costs and minimal thermal drift by leveraging the complementary strengths of each material
Solution Approach 2:
The patent carefully selects and optimizes specific optical parameters for each lens element to compensate for thermal drift. The glass lens is designed with an Abbe number greater than 60 to minimize chromatic aberration and thermal sensitivity, while the plastic lenses are designed with specific refractive power ranges (-1.5 to -2.5 for the first, +1.0 to +2.0 for the second) to balance the thermal characteristics. By adjusting these parameters, the overall lens system maintains stable optical performance across temperature variations while keeping fabrication costs low
3Manufacturing precision
If multiple lenses are used to achieve wide viewing angles and high resolution, then the imaging quality is improved, but the device complexity increases
Solution Approach 1:
The optical lens is segmented into five distinct lens elements with specific functions: a first plastic lens (negative refractive power) for wide-angle correction, a second plastic lens (positive refractive power) for focal length adjustment, a third plastic lens (negative refractive power) for aberration correction, a fourth glass lens (positive refractive power, Abbe number >60) for thermal stability and chromatic aberration correction, and a fifth plastic lens (positive refractive power) for final image formation. Each segment is optimized for specific optical corrections, allowing the system to achieve high resolution and wide viewing angles with a manageable number of elements rather than requiring excessive lenses
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 achieves low-profile and compact optical lenses with wide viewing angles, high resolution, reduced distortion, and 24-hours confocal image-capturing capability while maintaining low fabrication costs and minimizing thermal drift, ensuring good imaging quality across varying temperatures.
Implementation Method 1
an optical lens includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order from a magnified side to a minified side. A sum of refractive powers of the first lens and the second lens is negative, and a sum of refractive powers of the third lens, the fourth lens and the fifth lens is positive.
Data Source
AI summary
An optical lens includes a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in order from a magnified side to a minified side. A sum of refractive powers of the first lens and the second lens is negative, and a sum of refractive powers of the third lens, the fourth lens and the fifth lens is positive. The first lens is a glass lens with a negative refractive power, the second lens is a plastic lens, and the third lens, the fourth lens and the fifth lens are composed of one glass lens with an Abbe number of larger than 60 and two plastic lenses.