Compact Imaging Lens with Aspheric Inflection Points for Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional imaging lenses for small cameras, such as smartphones, face challenges in achieving both downsizing and proper aberration correction, particularly in correcting chromatic aberrations and maintaining a low profile while maintaining high resolution.
Innovation Solution
The imaging lens configuration includes a specific arrangement of lenses with varying refractive powers and aspheric surfaces, including a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with negative refractive power, and an eighth lens with negative refractive power having an aspheric image-side surface with at least one inflection point, which allows for proper correction of chromatic aberrations and reduction in profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses is increased to correct aberrations, then aberration correction is improved, but the total track length increases and the lens profile becomes larger
Solution Approach 1:
The patent applies parameter changes by utilizing aspheric surfaces with inflection points on specific lenses (7th and 8th lenses). This changes the geometric parameters of the lens surfaces, enabling better aberration correction without increasing the total track length. The aspheric coefficients and inflection point positions are optimized to achieve high-resolution imaging while maintaining a compact profile suitable for mobile devices.
2Length of stationary object
If the total track length is reduced for downsizing, then the lens profile is reduced, but aberration correction becomes insufficient
Solution Approach 1:
The patent applies local quality by introducing aspheric surfaces with inflection points specifically on the 7th and 8th lenses, rather than modifying all lenses uniformly. This localized application of aspheric design allows targeted correction of aberrations in critical regions of the optical path while maintaining a short total track length. The inflection points are strategically positioned to correct chromatic and spherical aberrations without requiring additional lens elements.
3Ease of manufacture
If conventional spherical surfaces are used, then manufacturing is easier, but chromatic aberration and field curvature cannot be properly corrected
Solution Approach 1:
The patent applies spheroidality by replacing conventional spherical lens surfaces with aspheric surfaces that have inflection points. The aspheric surfaces on the 7th and 8th lenses feature complex curvature profiles that cannot be described by simple spherical equations. This enables proper correction of chromatic aberration, field curvature, and distortion while maintaining manufacturability through precision molding techniques commonly used in the optical industry.
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 enables effective correction of chromatic aberrations across a wide range of wavelengths, axial chromatic aberration, and magnification, while also reducing the lens profile and maintaining a wide field of view, suitable for high-resolution imaging in compact camera systems.
Implementation Method 1
The eighth lens has an aspheric image-side surface having at least one inflection point
Implementation Method 2
field curvature and distortion at an image periphery can be properly corrected
Implementation Method 3
chromatic aberration can be properly corrected for wavelengths in a wide range
Implementation Method 4
a first lens with positive refractive power, a second lens with negative refractive power, a third lens with positive refractive power, a fourth lens with negative refractive power
Implementation Method 5
forms an image of an object on an image sensor
Implementation Method 6
an imaging lens for forming an image of an object on an image sensor
Data Source
AI summary
There is provided a compact imaging lens configured to properly correct aberrations. The imaging lens includes, in order from an object side to an image side, a first lens L1 with positive refractive power, a second lens L2 with negative refractive power, a third lens L3 with positive refractive power, a fourth lens L4 with negative refractive power, a fifth lens L5, a sixth lens L6, a seventh lens L7 with positive refractive power, and an eighth lens L8 with negative refractive power.The fourth lens is formed in a shape of a meniscus lens having an object-side surface being concave in a paraxial region. The eighth lens L8 has an aspheric image-side surface having at least one inflection point. Furthermore, the following conditional expression is satisfied:0.04<D34/f<0.15wheref: a focal length of the overall optical system of the imaging lens, andD34: a distance along the optical axis between the third lens and the fourth lens.