Four-Element Aspheric Lens System for Compact Mobile Imaging
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Solution Overview
Problem
Conventional compact image optical lens systems for mobile electronic products face challenges in achieving high pixel image sensors, large chief ray angles, and excellent imaging quality while maintaining a compact size, as they often result in long total track lengths and inadequate image quality.
Innovation Solution
The proposed image optical lens system consists of a specific configuration of four lens elements with aspheric surfaces, including a first lens with positive refractive power, a second with negative refractive power, a third with positive refractive power made of plastic and aspheric surfaces, and a fourth with negative refractive power, optimizing the chief ray angle, curvature radii, and thickness relationships to reduce the total track length and enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a three-element lens structure is used to achieve compact size, then the total track length is reduced, but the image quality deteriorates
Solution Approach 1:
The lens system is divided into four distinct lens elements with specific refractive powers and surface configurations. Each element performs a specific optical function, allowing the system to achieve compact size while maintaining image quality through coordinated action of multiple segmented components rather than a single complex element.
Solution Approach 2:
The patent employs aspheric surfaces on multiple lens elements, including the object-side surface of the first lens element and both surfaces of the fourth lens element. These curved non-spherical surfaces enable better control of light rays, reducing aberrations and improving image quality within a compact form factor.
2Manufacturing precision
If a four-element lens structure is used to achieve high image quality, then the image quality is improved, but the total track length becomes too long for compact electronic products
Solution Approach 1:
The patent specifies precise parameter relationships between lens elements, including curvature radii ratios (0.5<R1/R2<2), thickness ratios (0.3<CT1/CT2<1.5), and refractive power distributions. These parameter optimizations enable the four-element system to achieve high image quality while controlling the total track length for compact applications.
Solution Approach 2:
The lens system combines different materials with varying refractive indices and dispersion properties across the four elements. This composite approach allows each element to contribute differently to image formation, achieving superior image quality and aberration correction within a compact configuration.
3Manufacturing precision
If the chief ray angle is increased to match high pixel image sensors, then the photosensing performance is improved, but the back focal length and total track length become too long
Solution Approach 1:
The fourth lens element serves multiple functions simultaneously: it corrects optical aberrations, controls the chief ray angle to match sensor requirements, and contributes to compacting the overall system length. This multi-functional design allows the system to achieve large chief ray angles without proportionally increasing the back focal length.
Solution Approach 2:
The patent addresses the chief ray angle issue by optimizing the angular distribution of light rays in addition to axial dimensions. Through careful design of lens surface curvatures and positions, the system achieves large chief ray angles (improving sensor coupling) while maintaining compact axial length through sophisticated ray control in multiple dimensions.
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 effectively reduces the total track length, corrects aberrations, and enhances image quality, allowing for a compact and high-performance image optical lens system suitable for mobile electronic products with improved chief ray angles and image resolution.
Implementation Method 1
a first lens element (110) with positive refractive power
Implementation Method 2
a second lens element (120) with negative refractive power
Implementation Method 3
a third lens element (130) with positive refractive power
Implementation Method 4
a fourth lens element (140) with negative refractive power
Data Source
AI summary
An image optical 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 and a fourth lens element. The first lens element with positive refractive power has a convex object-side surface. The second lens element has negative refractive power. The third lens element with positive refractive power is made of plastic material and has a convex image-side surface, wherein an object-side surface and the image-side surface of the third lens element are aspheric. The fourth lens element with negative refractive power is made of plastic material, and has a concave object-side surface and a concave image-side surface, wherein the object-side surface and the image-side surface of the fourth lens element are aspheric, and the image-side surface of the fourth lens element changes from concave at the paraxial region to convex at the peripheral region.