Four-Lens Imaging Assembly with Aspheric Surfaces for Compact Mobile Camera Design
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Solution Overview
Problem
Conventional imaging lens assemblies for mobile phone cameras face challenges in reducing total track length, simplifying manufacturing processes, and controlling sensitivity while maintaining high image quality and resolution.
Innovation Solution
The proposed imaging lens assembly consists of four lens elements with specific refractive powers and surface configurations, including a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power and aspheric surfaces, and a fourth lens element with negative refractive power and an inflection point, along with an aperture stop placement between the first and second lens elements, optimizing the on-axis spacing and Abbe numbers to achieve a compact design and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If spherical-surface glass lenses are used and adhered together to form a doublet, then chromatic aberration is corrected, but the total track length cannot be reduced easily and manufacturing becomes complicated
Solution Approach 1:
The patent changes the surface geometry parameter from spherical to aspherical for the lens elements. This allows a single lens element to achieve both chromatic aberration correction and reduced total track length, eliminating the need for complex multi-element doublet assemblies while maintaining manufacturing feasibility.
Solution Approach 2:
The patent extracts the chromatic aberration correction function from the complex multi-element doublet structure and integrates it into a simplified single aspherical lens element design, reducing overall system complexity while maintaining the correction capability.
2Manufacturing precision
If spherical-surface glass lenses are used and adhered together to form a doublet, then chromatic aberration is corrected, but the freedom of the system is curtailed
Solution Approach 1:
By changing from spherical to aspherical surface geometry, the patent gains additional design parameters (aspherical coefficients) that provide greater freedom in optimizing the optical system for chromatic aberration correction while allowing more flexible system configuration and reduced track length.
3Length of moving object
If the aperture stop is placed in front of the first lens element, then the total track length is reduced, but the sensitivity of the system increases
Solution Approach 1:
The patent employs aspherical surfaces on the lens elements, which provide additional degrees of freedom in the optical design. This allows the system to achieve reduced total track length with the aperture stop positioned optimally while compensating for increased sensitivity through the aberration-correcting capability of the aspherical surfaces.
4Measurement precision
If more lens elements are added to reduce total track length, then image quality improves, but manufacturing complexity increases
Solution Approach 1:
The patent uses aspherical lens elements that combine multiple optical correction functions within fewer elements. The aspherical surfaces act as a composite optical solution, integrating what would traditionally require multiple separate spherical elements into a more compact and manufacturable design with reduced element count.
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, mitigates sensitivity, and enhances image resolution, enabling a wide field of view and improved correction of aberrations, making it suitable for high-resolution mobile phone cameras.
Implementation Method 1
a first lens element with positive refractive power having a convex object-side surface and a convex image-side surface; a second lens element with negative refractive power having a concave object-side surface; a third lens element with positive refractive power having a convex image-side surface
Data Source
AI summary
This invention provides an imaging lens assembly comprising: in order from an object side to an image side: a first lens with positive refractive power having a convex object-side surface and a convex image-side surface; a second lens with negative refractive power having a concave object-side surface; a third lens with positive refractive power having a convex image-side surface, at least one of both surfaces thereof being aspheric; and a fourth lens with negative refractive power having a convex object-side surface and a concave image-side surface on which at least one inflection point is formed; wherein there are four lenses with refractive power, an on-axis spacing between an aperture stop and an electronic sensor provided therein is SL, an on-axis spacing between the object-side surface of the first lens and the electronic sensor is TTL, they satisfy the relation: 0.75<SL/TTL<0.90.