Capsule Endoscope Lens System with Aspheric Surfaces
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Solution Overview
Problem
Capsule endoscopes face challenges in obtaining high-quality images due to their short data collection time and potential non-optimal positioning, requiring high-quality, wide-angle, large-field-of-view optics with compact size, low cost, and minimal lens elements while maintaining good optical quality.
Innovation Solution
A lens system comprising a first concave aspheric lens, a second convex aspheric lens, and a third convex aspheric lens, with specific radius and Abbe number relationships, and a stop to maintain symmetric performance, achieving a large field of view, compact size, and low cost with only three lens elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide-angle lens system is used to increase field of view, then the field of view is improved, but the lens system size and complexity increase
Solution Approach 1:
The lens system is divided into three separate lens elements (first lens, second lens, and third lens) with specific aspheric surface characteristics. This segmentation allows each lens to contribute to specific optical functions while maintaining overall compactness and controlling aberrations, resolving the contradiction between wide field of view and system complexity
Solution Approach 2:
The patent employs aspheric surfaces on all three lens elements instead of traditional spherical or flat surfaces. The aspheric curvature (with specific coefficients k1, k2, k3) enables the lens system to achieve wide field of view while controlling optical aberrations and maintaining compact size, directly addressing the contradiction between field of view and complexity
2Reliability
If multiple lens elements are used to improve optical quality, then optical quality is improved, but manufacturing cost and complexity increase
Solution Approach 1:
Each lens element is designed with specific local optical characteristics (different aspheric coefficients, different positions) to address specific optical requirements at different locations in the optical path. This localized optimization achieves high optical quality with only three lens elements, avoiding the need for more complex and expensive multi-element systems
Solution Approach 2:
The patent optimizes specific parameters (aspheric coefficients k1, k2, k3, lens positions, curvatures) to achieve the desired optical performance. By carefully selecting and adjusting these parameters, the system achieves high optical quality with minimal lens elements, reducing manufacturing complexity and cost
3Volume of moving object
If the lens system is made compact to fit capsule endoscope constraints, then size is improved, but field of view and optical quality deteriorate
Solution Approach 1:
The three lens elements are arranged in a compact nested configuration within the capsule endoscope housing. The lenses are positioned close together with precise spacing, allowing the entire lens system to fit within the limited space of the capsule while still achieving wide field of view through the aspheric surface design
Solution Approach 2:
The aspheric surfaces on all lens elements enable the system to achieve wide field of view within a compact volume. The specific aspheric coefficients and curvatures are designed to maximize the field of view while keeping the overall lens system size minimal, directly resolving the contradiction between size and field of view
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 lens system provides a large field of view exceeding 110°, compact size, low cost, and good optical quality with nominal aberrations, enhancing image acquisition in capsule endoscopes.
Implementation Method 1
a first lens having a concave aspheric surface having a radius R2 and a second lens having a convex aspheric surface having a radius R3 facing the first lens
Data Source
AI summary
A lens system and a for a capsule endoscope includes a first lens having a concave aspheric surface having a radius R2 and a second lens having a convex aspheric surface having a radius R3 facing the first lens. A third lens has a convex aspheric surface having radius R6. The lens system satisfies the following conditions: (1) R2/Gap>1 and ABS(R3/R2)>1.28; (2) 1<ABS(R6/R2)<1.1 and R6<0; and (3) V2<V1 and V2<V3; wherein: i) Gap is a distance from a center of curvature of the concave aspheric surface of the first lens to a center of curvature of the convex aspheric surface of the second lens; (ii) ABS denotes absolute value; and (iii) V1 is an Abbe number of the first lens, V2 is an Abbe number of the second lens, and V3 is an Abbe number of the third lens.