Thin Resin Infrared Lens Structure for Higher IR Transmittance
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Solution Overview
Problem
Infrared optical systems are not widely used due to high costs, primarily attributed to expensive lenses, and existing materials like Ge, Si, ZnSe, ZnS, and chalcogenide glass are either costly, toxic, or have poor workability and infrared transmittance, while PE resin, although cost-effective, has low transmittance when formed into a thick central part.
Innovation Solution
Infrared lenses made of resin with an average thickness of 0.5 mm or less, featuring a Fresnel surface and aspheric shape, and optionally combined with inorganic lenses, to achieve high infrared transmittance and reduced material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single PE resin lens is used to form an image, then the lens can be made with good formability and low cost, but the central part becomes thick which decreases infrared transmittance
Solution Approach 1:
The patent divides the imaging function into multiple lenses (first lens and second lens) instead of using a single thick lens. This segmentation allows each lens to have thinner individual thickness while collectively achieving the required imaging power, thereby maintaining high infrared transmittance while preserving the advantages of PE resin formability and low cost
Solution Approach 2:
The patent uses a composite lens system combining PE resin lenses with other infrared-transmissive materials. The first lens is made of PE resin and the second lens is made of a different material, creating a composite optical system that balances cost, formability, and infrared transmittance performance
2Reliability
If Ge or Si materials are used for lenses, then good infrared transmittance is achieved, but the materials have poor workability and high cost
Solution Approach 1:
The patent replaces expensive and difficult-to-manufacture materials like Ge and Si with PE resin, which is cheaper and has excellent formability. Although PE resin has lower inherent transmittance, the multi-lens design compensates for this, achieving acceptable overall performance at lower cost and with much better workability
Solution Approach 2:
The patent creates a composite optical system that combines PE resin lenses with other materials to achieve the required infrared transmittance without using expensive Ge or Si materials throughout, thus improving workability and reducing cost while maintaining adequate transmittance
3Ease of manufacture
If ZnSe, ZnS, or chalcogenide glass are used for lenses, then aspheric surfaces can be formed by molding, but the materials are toxic and costly
Solution Approach 1:
The patent replaces toxic and costly materials like ZnSe, ZnS, and chalcogenide glass with PE resin, which is non-toxic and inexpensive. The PE resin lenses can be molded into aspheric surfaces, maintaining the manufacturing advantages while eliminating the harmful and costly aspects of the alternative materials
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 solution provides infrared lenses with high transmittance, reduced material costs, and improved formability, enabling cost-effective infrared applications.
Implementation Method 1
one optical surface of the first infrared lens is a Fresnel surface
Implementation Method 2
one optical surface of the first infrared lens is a Fresnel surface
Implementation Method 3
the other optical surface of the first infrared lens has an aspheric shape having an inflection point
Data Source
AI summary
An infrared lens transmits infrared rays. The infrared lens is made of resin. An average thickness of the infrared lens within an optically effective diameter is 0.5 mm or less.