Five-Element Lens System with Aspheric Surfaces for Wide Field of View
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Solution Overview
Problem
Conventional compact optical systems with a wide field of view struggle to achieve high resolution and image quality due to issues like image distortion, vignetting, and difficulty in miniaturization, especially with five-element lens structures that attempt to enhance the field of view but face problems with refractive power and image quality.
Innovation Solution
A photographing lens system comprising five lens elements with specific refractive powers and surface shapes, including aspheric surfaces with inflection points, and air gaps between adjacent elements, optimized by conditions such as curvature radii and thickness ratios to correct aberrations and maintain compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a five-element lens structure is used to enlarge the field of view, then the field of view is widened, but image distortion and vignetting occur at the periphery
Solution Approach 1:
The patent applies aspheric surfaces to multiple lens elements (first, second, fourth, and fifth lens elements have aspheric object-side or image-side surfaces). The aspheric coefficients are specifically designed to correct peripheral image distortion and vignetting while maintaining the wide field of view enabled by the five-element structure. This resolves the contradiction by using curved surface geometry to eliminate the harmful effects of the complex lens arrangement.
2Adaptability or versatility
If the refractive power of lens elements is increased to enlarge the field of view, then the field of view is widened, but difficulty in miniaturization occurs
Solution Approach 1:
The patent employs specific parameter ranges for lens curvature radii, thicknesses, and refractive powers to achieve wide field of view while controlling overall size. The conditional expressions (0.5 < f12/f < 2.0, 0.3 < CT2/ΣCT < 0.8, etc.) define optimized parameter ranges that balance field of view enlargement with miniaturization requirements.
Solution Approach 2:
The optical system is divided into five separate lens elements with air gaps between them, allowing independent optimization of each element's refractive power and surface shape. This segmentation enables the system to achieve wide field of view through distributed optical power rather than concentrating it in a single strong lens, thereby avoiding excessive size.
3Manufacturing precision
If more lens elements are added to improve image quality, then image quality is improved, but device complexity increases
Solution Approach 1:
By using aspheric surfaces on multiple lens elements, the patent achieves superior image quality correction (distortion, astigmatism, spherical aberration) without requiring additional lens elements. The aspheric geometry provides extra degrees of freedom for aberration control, allowing five elements to perform the work that would otherwise require more elements, thus reducing structural complexity.
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 a compact optical system with a wide field of view, improved image quality, reduced distortion, and enhanced manufacturability, effectively addressing the limitations of conventional systems by optimizing lens element arrangements and materials like plastic or glass.
Implementation Method 1
The fourth lens element with negative refractive power has a concave object-side surface, wherein the object-side surface and an image-side surface of the fourth lens element are aspheric. The fifth lens element with positive refractive power has a convex object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the fifth lens element are aspheric
Data Source
AI summary
A photographing lens system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element and a fifth lens element. The first lens element with negative refractive power has a concave image-side surface. The second lens element has refractive power. The third lens element with positive refractive power has a convex object-side surface and a convex image-side surface. The fourth lens element with negative refractive power has a concave image-side surface, wherein an object-side surface and the image-side surface of the fourth lens element are aspheric. The fifth lens element with positive refractive power has a convex object-side surface and a convex image-side surface, wherein the object-side surface and the image-side surface of the fifth lens element are aspheric.