Air-Spaced Imaging Lens Design for Thermal Stability
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Solution Overview
Problem
Existing imaging lenses used in onboard and surveillance cameras face challenges in achieving a balance between environmental resistance, cost-effectiveness, and maintaining performance across varying temperatures, with cemented lenses experiencing adhesive degradation and increased costs due to specialized processing.
Innovation Solution
The design of an imaging lens comprising a front group with a negative power and a rear group with a positive power, utilizing single glass lenses with specific Abbe numbers and curvature configurations to enhance environmental resistance without the need for cemented lenses, thus avoiding costly processing and maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a cemented lens is used to achieve reduction in size, then the lens becomes more compact, but the adhesive material degrades under severe environment causing optical performance deterioration
Solution Approach 1:
The patent removes the cemented lens structure entirely, extracting the adhesive layer that causes degradation under severe environmental conditions. The lens system is redesigned as a air-spaced configuration where individual lenses are separated by air gaps rather than being cemented together, eliminating the source of environmental degradation while maintaining optical performance.
Solution Approach 2:
The patent avoids using expensive and environmentally vulnerable cemented adhesives by adopting a simpler air-spaced design. This approach uses only the lens elements themselves separated by air gaps, eliminating the need for specialized adhesive materials that would degrade under temperature and humidity variations.
2Speed
If multiple lenses made of material having refractive index larger than 1.9 are used to achieve fast lens performance, then the F number is reduced, but the manufacturing cost increases
Solution Approach 1:
The patent achieves fast lens performance (F number 2.0) by optimizing the arrangement and parameters of standard glass lenses rather than using expensive high-refractive-index materials. The specific configuration of lens powers, curvatures, and spacings is optimized to achieve the desired focal ratio using conventional optical materials, thereby reducing manufacturing costs while maintaining speed.
3Volume of moving object
If aspheric lenses are used to achieve compact design, then the lens size is reduced, but significant performance change occurs due to temperature when made of plastic
Solution Approach 1:
The patent employs a composite lens design combining multiple glass elements with different refractive indices and dispersive properties. This composite structure achieves compact focal length while using glass materials that are thermally stable, avoiding the temperature sensitivity inherent in plastic aspheric lenses. The combination of multiple glass elements provides both compactness and thermal stability.
4Manufacturing precision
If glass mold is used to form lenses to achieve precise shape, then the lens surface precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces complex glass molding processes with precision mechanical grinding and polishing techniques. This substitution allows for achieving the required lens surface precision through controlled mechanical removal of material rather than through expensive glass molding, thereby reducing manufacturing costs while maintaining optical quality.
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 improves environmental resistance and optical performance while reducing manufacturing costs, allowing for a compact, fast, and low-cost lens capable of withstanding extreme temperatures, and effectively correcting chromatic and field aberrations.
Implementation Method 1
an imaging lens including, in order from the object side, a front group having a negative power, a stop, and a rear group having a positive power... Each lens constituting the front group and the rear group is a single lens
Data Source
AI summary
An imaging lens is provided and includes, in order from the object side, a front group having a negative power, a stop, and a rear group having a positive power. The front group includes, in order from the object side, a first negative lens having a meniscus shape with a concave surface on an image side, a second negative lens, and a third positive lens. The rear group includes, in order from the object side, a fourth positive lens, a fifth negative lens having a meniscus shape with a concave surface on the object side, and a sixth positive lens. An Abbe number of each of the first lens, the second lens, the fourth lens, and the sixth lens at the d-line is equal to or larger than 40, and an Abbe number of each of the third lens and the fifth lens at the d-line is equal to or smaller than 40. Each lens constituting the front group and the rear group is a single lens.