Five-Lens Optical Imaging System with Inflection Point for Compact High Resolution
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Solution Overview
Problem
The challenge is to develop an optical imaging system with five lenses that has a short total track length (TTL) to facilitate its mounting in small portable terminals while maintaining high resolution, as increasing the number of lenses in an optical imaging system typically results in a longer TTL, making it difficult to fit within compact spaces.
Innovation Solution
The optical imaging system is designed with specific lens configurations, including a first lens with convex surfaces, a second lens with concave surfaces, a third lens with a concave object-side and convex image-side surface, a fourth lens with concave surfaces, and a fifth lens featuring an inflection point on its image-side surface, along with a filter of reduced thickness, to satisfy conditions such as TTL/(ImgH*2) < 0.65 and 80 < FOV, ensuring a compact form while achieving high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of lenses is increased to five lenses to achieve high resolution, then the resolution is improved, but the total track length (TTL) is increased making it difficult to mount in small portable terminals
Solution Approach 1:
The patent applies parameter changes by optimizing the refractive indices, curvature radii, and thicknesses of the five lenses to achieve a compact design. Specifically, the fifth lens has an inflection point on its image-side surface with controlled curvature, and the lens parameters satisfy specific conditional expressions (e.g., -1.50 < (Rr5/Rr6) < -0.50 where Rr5 and Rr6 are curvature radii at the inflection point and vertex respectively). These parameter optimizations enable high resolution with a reduced total track length suitable for portable terminals.
2Reliability
If the fifth lens has an inflection point on its image-side surface to control aberrations, then the optical performance is improved, but the lens design complexity is increased
Solution Approach 1:
The patent applies local quality by introducing an inflection point specifically on the image-side surface of the fifth lens. This localized structural feature allows precise control of optical aberrations (such as spherical and coma aberrations) in the critical image-forming region without requiring complex designs in all lenses. The inflection point creates a specific curvature profile that locally optimizes light ray convergence, improving optical performance while maintaining overall design manageability.
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 allows for the miniaturization of the optical imaging system, enabling it to be easily mounted in small terminals while achieving high resolution, as demonstrated by the satisfaction of various conditional expressions and characteristics such as TTL ≤ 3.80 mm and 80 < FOV, thereby realizing a high-resolution imaging system within a compact form factor.
Implementation Method 1
a fifth lens having an inflection point formed on an image-side surface thereof
Data Source
AI summary
An optical imaging system includes a first lens, a second lens, a third lens, a fourth lens, and a fifth lens having an inflection point formed on an image-side surface thereof. The first to fifth lenses are sequentially disposed from an object side to an imaging plane. The optical imaging system satisfies TTL/(ImgH*2)<0.65, where TTL is a distance from an object-side surface of the first lens to the imaging plane, and ImgH*2 is a diagonal length of the imaging plane.