Aspheric Lens Assembly Reducing Total Track Length
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Solution Overview
Problem
Conventional high-resolution compact photographing optical lens assemblies face challenges in reducing optical sensitivity and total track length due to the arrangement of spherical lenses, which complicates manufacturing and image quality.
Innovation Solution
A photographing optical lens assembly comprising four lens elements with specific refractive powers and surface curvatures, where the aperture stop is positioned between the first and second lens elements, and the electronic sensor is on the image plane, optimizing the distribution of refractive power to reduce sensitivity and total track length while maintaining high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spherical lenses are used in the lens assembly, then manufacturing is simplified, but the total track length increases and design freedom is limited
Solution Approach 1:
The patent applies aspheric surfaces to lens elements instead of traditional spherical surfaces. This allows for more compact optical design with reduced total track length while maintaining manufacturing feasibility through modern molding techniques. The aspheric profiles enable better aberration control and shorter focal length arrangements.
Solution Approach 2:
The patent changes the geometric parameters of lens surfaces from spherical to aspheric configurations. This parameter change enables more flexible optical path design, allowing reduction of the total track length while maintaining image quality and correcting aberrations more effectively.
2Reliability
If multiple spherical lenses are combined into a doublet structure, then chromatic aberrations are corrected, but the arrangement complexity increases and total track length is limited
Solution Approach 1:
The patent uses aspheric lens elements that can correct chromatic aberrations without requiring complex multi-element doublet structures. The aspheric profiles provide additional degrees of freedom for aberration control, simplifying the overall lens arrangement while maintaining correction effectiveness.
Solution Approach 2:
By changing from spherical to aspheric surface parameters, the patent achieves chromatic aberration correction with fewer elements and simpler arrangement. The aspheric coefficients provide additional control parameters that replace the need for complex multi-element combinations.
3Device complexity
If the aperture stop is positioned in front of the first lens element, then the optical system is simplified, but the system sensitivity increases making yield control difficult
Solution Approach 1:
The patent employs aspheric lens elements that are less sensitive to positioning variations and manufacturing tolerances. This reduced sensitivity allows for easier yield control while maintaining the simplified aperture stop configuration in front of the first lens element.
Solution Approach 2:
By using aspheric surfaces with optimized parameters, the patent reduces the sensitivity of the optical system to manufacturing variations. This enables better yield control even with the aperture stop positioned in front of the first lens element, as the aspheric profiles compensate for tolerances more effectively than spherical surfaces.
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 and sensitivity of the optical system while achieving higher image quality by balancing refractive power and correcting aberrations, allowing for a more compact and efficient lens assembly.
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 and a concave image-side surface
Data Source
AI summary
This invention provides a photographing optical lens assembly, from an object side to an image side in order, comprising a first lens element with positive refractive power having a convex object-side surface, a second lens element with negative refractive power having a concave image-side surface, a third lens element with positive refractive power, a fourth lens element with negative refractive power having a concave image-side surface, both the two surfaces of the fourth lens thereof being aspheric. And an aperture stop is positioned between the first element and the second lens element. There are four lens elements with refractive power in the lens assembly.