Four-Element Imaging Lens Assembly Balancing Size and Image Quality
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Solution Overview
Problem
Conventional optical systems face challenges in achieving a balance among high image quality, low sensitivity, proper aperture size, miniaturization, and desirable field of view due to advancements in semiconductor technology and increasing functionality requirements.
Innovation Solution
An imaging system lens assembly comprising four lens elements with specific optical parameters and configurations, including reflective elements for optical path folding, to optimize image quality and compactness while allowing for miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical systems are used, then they can maintain simple structure, but they cannot achieve high image quality while meeting miniaturization and multi-functionality requirements
Solution Approach 1:
The optical system is divided into four distinct lens elements, each with specific refractive power characteristics (first and second lens elements with positive refractive power, third lens element with negative refractive power, fourth lens element with positive refractive power). This segmentation allows each element to contribute differently to aberration correction and image quality enhancement while maintaining overall system compactness.
Solution Approach 2:
Each lens element is designed with specific local optical properties including controlled Abbe numbers (V1, V2, V3), refractive indices (N1, N2, N3), and surface curvatures (R1-R8). The object-side and image-side surfaces of each lens element have different curvature characteristics to optimize local aberration correction. This localized optimization of optical properties enables high image quality in a compact configuration.
2Volume of moving object
If the lens assembly is miniaturized, then compactness is improved, but optical performance and image quality may deteriorate
Solution Approach 1:
The four lens elements are arranged in a nested configuration along the optical path with controlled axial distances between them. The lens elements are positioned closely together with specific spacing (axial distance between object-side surface of first lens element and image-side surface of fourth lens element is TD, and between image-side surface of fourth lens element and image surface is BL). This nested arrangement minimizes the overall axial length while maintaining sufficient optical path length for high-quality imaging.
Solution Approach 2:
The patent specifies precise parameter ranges to optimize the balance between compactness and image quality: 0 < TD/BL < 0.42 for axial distance ratio, 1.0 < Fno < 4.0 for f-number, and specific ranges for Abbe numbers (V1 > 20.0, V2 > 20.0, V3 > 20.0), refractive indices (N1 > 1.5, N2 > 1.5, N3 > 1.5), and curvature radii (R1, R2, R3, R4, R5, R6, R7, R8). These parameter optimizations enable miniaturization while preserving optical performance.
3Use of energy by moving object
If the aperture size is increased, then light gathering ability is improved, but sensitivity and depth of field control become problematic
Solution Approach 1:
The f-number is controlled within the range 1.0 < Fno < 4.0 to optimize the balance between light gathering ability and sensitivity control. The aperture size is indirectly controlled through the refractive powers and curvatures of the lens elements, particularly the positive refractive power of the first and second lens elements which help concentrate light while the negative refractive power of the third lens element provides depth of field control. This parameter optimization enables the system to achieve proper sensitivity and depth of field characteristics.
4Adaptability or versatility
If the field of view is expanded, then functionality is improved, but optical aberrations and image quality deteriorate
Solution Approach 1:
The four-lens-element configuration with differentiated refractive power distribution (positive, positive, negative, positive) enables the system to handle a broader field of view while correcting aberrations. Each lens element contributes to field curvature and distortion control, allowing expanded functionality without sacrificing image quality in the paraxial and off-axis regions.
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 assembly achieves improved image quality, compactness, and flexibility in design, addressing the balance of optical system requirements while reducing mechanical limitations and enhancing performance across various environments.
Implementation Method 1
Each of the four lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The second lens element has positive refractive power, and the object-side surface of the third lens element is convex in a paraxial region thereof.
Data Source
AI summary
An imaging system lens assembly includes, in order from an object side to an image side: a first lens element, a second lens element, a third lens element and a fourth lens element. Each of the four lens elements has an object-side surface facing toward the object side and an image-side surface facing toward the image side. The second lens element has positive refractive power. The object-side surface of the third lens element is convex in a paraxial region thereof.