Six-Element Aspheric Lens System for Compact Wide-Angle Imaging

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Solution Overview

Problem

Conventional optical lens systems for mobile devices and cameras face challenges in achieving a balance between a large field of view, compact size, and high image quality, with existing designs either compromising on image resolving power or total track length.

Innovation Solution

The optical photographing lens system consists of six elements with specific refractive powers and surface curvatures, including aspheric surfaces, arranged to optimize focal lengths and curvature radii, allowing for a compact design with improved image quality and field of view.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a negative-positive lens structure is used to achieve a wide field of view, then the field of view is enlarged, but the image resolving power becomes insufficient and the total track length is difficult to reduce

Engineering Contradiction:

Improvefield of viewVSAvoidimage resolving power

Core Design Contradiction:

Area of moving objectVSManufacturing precision

Solution Approach 1:

The lens system is divided into six distinct lens elements with alternating positive and negative refractive powers. This segmentation allows each element to be optimized for specific functions: the negative elements (first, fourth, sixth) expand the field of view while the positive elements (second, third, fifth) maintain image resolving power, resolving the contradiction between wide angle and sharpness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the lens elements have different surface characteristics. Aspheric surfaces are applied to specific elements (fourth, fifth, and sixth elements) to correct local optical aberrations in the wide-angle regions, while maintaining appropriate spherical surfaces in other areas to preserve overall image quality and resolving power

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a six-element lens structure is used to improve image resolving power, then the image quality is improved, but the back focal length cannot be reduced and the total track length is not easy to be reduced

Engineering Contradiction:

Improveimage resolving powerVSAvoidtotal track length

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The lens system inverts the conventional ordering by placing a negative refractive power element (sixth element) closest to the image plane. This inversion allows the back focal length to be reduced while maintaining six elements for sufficient resolving power, as the negative element near the sensor plane helps fold the light path more efficiently

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system employs aspheric surface parameters for the fourth, fifth, and sixth lens elements, with specific curvature radius ratios (|R10/R9|=0.05 to 0.30) that optimize the balance between compact total track length and maintained image resolving power across the six-element structure

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If conventional lens elements are used, then the manufacturing is simpler, but spherical aberration and astigmatism are not effectively reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidaberration control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The fourth, fifth, and sixth lens elements utilize aspheric surfaces instead of conventional spherical surfaces. This curvature modification effectively reduces spherical aberration and astigmatism by providing non-uniform surface power distribution, while the aspheric coefficients are optimized to maintain manufacturability through standard molding or grinding processes

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 enhances image quality by reducing spherical aberration and astigmatism, enabling a larger field of view while maintaining a compact size, suitable for applications in digital cameras and mobile devices.

Implementation Method 1

The fourth lens element has refractive power, wherein at least one surface of the fourth lens element is aspheric. The fifth lens element with positive refractive power has a convex image-side surface and both of the surfaces are aspheric. The sixth lens element with negative refractive power has an image-side surface changing from concave at a paraxial region to convex at a peripheral region, and both of the surfaces are aspheric.

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8743477B2Optical photographing lens system

Publication Date: 2014.06.03 LARGAN PRECISION

AI summary

An optical photographing 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, a fourth lens element, a fifth lens element and a sixth lens element. The first lens element with negative refractive power has a convex object-side surface and a concave image-side surface. The second lens element has positive refractive power. The third lens element has refractive power. The fourth lens element has refractive power, wherein at least one surface of the fourth lens element is aspheric. The fifth lens element with positive refractive power has a convex image-side surface and both of the surfaces are aspheric. The sixth lens element with negative refractive power has an image-side surface changing from concave at a paraxial region to convex at a peripheral region, and both of the surfaces are aspheric.