Gradient-Index Lens for Wide-Angle Chromatic Aberration Correction
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Solution Overview
Problem
Conventional wide-angle lenses struggle to achieve chromatic aberration correction while providing wide viewing angles and high-quality imaging for both visible and infrared light, often requiring a greater number of lens elements or varying the thickness of the optical filter.
Innovation Solution
The imaging lens design includes a first lens with negative refractive power, a gradient-index (GRIN) or inhomogeneous material lens, and an aperture stop disposed between the outermost lenses, satisfying the condition of 1<D/T<32, where D is the maximum outer diameter and T is the thickness of the GRIN or inhomogeneous material lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional wide-angle lenses use more lens elements or vary optical filter thickness to correct chromatic aberration, then chromatic aberration correction improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies parameter changes by utilizing a gradient-index lens where the refractive index varies continuously along the optical axis according to a specific mathematical function. This continuous variation of the refractive index parameter enables effective chromatic aberration correction without requiring multiple discrete lens elements, thus resolving the contradiction between correction quality and device complexity
Solution Approach 2:
The patent employs composite materials by combining the gradient-index lens with conventional homogeneous lenses in a hybrid optical system. The gradient-index lens is made from special optical materials with spatially varying refractive indices, while other elements use traditional homogeneous optical materials, creating a composite system that achieves superior chromatic aberration correction with reduced element count
2Manufacturing precision
If conventional wide-angle lenses use more lens elements to correct chromatic aberration, then imaging quality improves, but the lens size and overall length increase
Solution Approach 1:
The gradient-index lens utilizes continuous parameter variation of the refractive index along the optical axis, described by functions such as n(y) = n0 + n1*y or n(y) = n0 + n1*y + n2*y^2, where y is the distance from the optical axis. This parameter change approach provides strong chromatic dispersion control within a compact form factor, improving imaging quality without increasing overall lens length
Solution Approach 2:
The patent extracts the chromatic aberration correction function from multiple discrete lens elements and concentrates it into a single gradient-index lens element. By taking out this specific function and implementing it through refractive index gradient rather than through multiple cemented elements, the design achieves high imaging quality with reduced overall length
3Manufacturing precision
If conventional lenses use cemented lenses for chromatic aberration correction, then correction effectiveness improves, but manufacturing cost and production complexity increase
Solution Approach 1:
The patent extracts the chromatic aberration correction capability from traditional cemented lens assemblies and implements it through a single gradient-index lens element. This extraction eliminates the need for complex cementing processes, multiple material matching requirements, and alignment procedures, significantly simplifying manufacturing while maintaining correction effectiveness
Solution Approach 2:
The gradient-index lens can be manufactured using modern techniques such as direct injection molding or precision glass forming, which are more cost-effective and scalable than traditional multi-element cemented lens assembly. The single-element design reduces material waste, assembly time, and quality control complexity, making production more economical
4Manufacturing precision
If conventional wide-angle lenses are designed for visible light, then visible light imaging quality improves, but infrared light imaging performance deteriorates
Solution Approach 1:
The gradient-index lens is designed with a refractive index profile that provides effective chromatic aberration correction across a broad spectral range covering both visible and infrared wavelengths. The optical system achieves multi-functionality by simultaneously optimizing performance for visible light imaging and infrared light imaging, allowing the same lens design to serve both applications without requiring separate optimized designs
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 effectively corrects chromatic aberration while maintaining wide viewing angles, achieving high-quality imaging in both visible and infrared light without altering the optical filter thickness, and is cost-effective by reducing the number of cemented lenses.
Implementation Method 1
one of the no more than nine lenses is a gradient-index (GRIN) lens. The gradient-index lens satisfies a condition of 1<D/T<32, where D is a maximum outer diameter of the gradient-index lens and T is a thickness of the gradient-index lens along an optical axis of the imaging lens
Implementation Method 2
one of the no more than nine lenses is an inhomogeneous material lens. Two opposite surfaces of the inhomogeneous material lens along an optical axis of the imaging lens have different refractive indices
Data Source
AI summary
An imaging lens includes a first lens, a second lens and a third lens arranged in order from an object side to an image side. The first lens has a negative refractive power, the imaging lens includes no more than nine lenses with refractive powers, and one of the no more than nine lenses has a gradient refractive index. An aperture stop is disposed between two outermost lenses with refractive powers at opposite ends of the imaging lens. The lens having a gradient refractive index satisfies a condition of1<D/T<32, where D is a maximum outer diameter of the lens having a gradient refractive index, and T is a thickness of the lens having a gradient refractive index measured along an optical axis of the imaging lens.