Near-Infrared Objective Lens Using Barrel Distortion
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Solution Overview
Problem
Commercial cell phone camera lenses are not optimized for near-infrared imaging, failing to provide near-diffraction limited image quality due to limitations in focal length and pixel size, especially under low light conditions, and cannot be simply scaled to achieve faster F# values.
Innovation Solution
A compact objective lens assembly with specific aspheric and meniscus lens elements, including a field corrector, is designed for near-infrared imaging, utilizing negative 'barrel' distortion to increase focal length while maintaining a wide field of view and fast F# of at least 1.44, incorporating materials like Cyclic Olefin Copolymer and AL-6263 for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If commercial cell phone camera lenses are designed with complex non-spherical surfaces to correct geometric aberrations and achieve low distortion (±3%), then image quality over a large field of view is improved, but the lens assembly cannot achieve near-diffraction limited image quality in the near-infrared spectrum with faster F# values
Solution Approach 1:
The patent applies parameter changes by deliberately introducing negative optical distortion (barrel distortion) into the lens design, which increases the axial focal length while maintaining the same field of view. This parameter modification allows the lens to achieve near-diffraction limited image quality in the near-infrared spectrum with faster F# values, resolving the contradiction between visible spectrum optimization and near-infrared performance
Solution Approach 2:
Instead of correcting distortion as is done in conventional lenses, this patent inverts the approach by deliberately introducing negative distortion to achieve the desired optical performance. The field corrector element is designed to produce controlled barrel distortion, which paradoxically improves near-infrared imaging capability and enables faster F# values
2Manufacturing precision
If the focal length is increased to improve image resolution, then near-diffraction limited image quality is achieved, but the lens assembly length increases
Solution Approach 1:
The patent inverts the conventional approach by introducing negative distortion that increases the axial focal length. This allows the effective focal length to be longer (improving resolution) while the physical lens assembly length remains compact, as the negative distortion compensates for the increased focal length requirement
3Area of stationary object
If the field of view is widened to ±32.5°, then coverage area is improved, but maintaining near-diffraction limited image quality becomes more difficult
Solution Approach 1:
The patent changes the distortion parameter to negative values, which allows the lens to maintain near-diffraction limited image quality across a wide ±32.5° field of view. The controlled barrel distortion helps manage the trade-off between wide field coverage and image quality by adjusting the light path geometry
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
The design achieves near-diffraction limited image resolution over a ±32.5° field of view in the near-infrared spectrum with improved light gathering capabilities and reduced distortion, enabling better image quality and increased pixel density without increasing the lens length.
Implementation Method 1
A compact objective lens with enhanced distortion for near-infrared imaging comprises a positively powered, aspheric, and meniscus first lens element; a negatively powered, aspheric, and meniscus second lens element
Implementation Method 2
most have complex non-spherical surface shapes that correct geometric aberrations over a large field of view
Data Source
AI summary
The current invention describes a compact objective lens with enhanced distortion for near-infrared imaging, comprising a positively powered, aspheric, and meniscus first lens element; a negatively powered, aspheric, and meniscus second lens element; a positively powered, aspheric, and biconvex third lens element; a negatively powered, aspheric, and meniscus fourth lens element; a negatively powered, aspheric, and meniscus field corrector element; and a detector assembly comprising a window and a detector plane where the light rays come to focus.