Three-Element Aspheric Lens System for Aberration Correction

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Solution Overview

Problem

Conventional photographic lens assemblies with two or three lens elements struggle to achieve superior imaging quality and compact size due to limited aberration correction capabilities, particularly in portable electronic devices.

Innovation Solution

A photographic lens system comprising three lens elements with specific refractive powers and surface curvatures, including a first lens with positive refractive power, a second lens with negative refractive power made of plastic, and a third lens with negative refractive power, optimized to satisfy specific curvature and thickness conditions for improved aberration correction and miniaturization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a two-lens structure is adopted to reduce manufacturing costs, then manufacturing cost is reduced, but aberration correction ability is limited and imaging quality deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoidaberration correction ability

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the optical system into three separate lens elements instead of two, with each element having specific refractive power characteristics (positive, negative, negative). This segmentation allows each lens element to address specific aberration types independently, improving overall aberration correction capability while maintaining cost-effectiveness through the use of plastic materials for the second and third elements.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If three lens elements are used to improve imaging quality, then imaging quality is improved, but the overall size of the lens assembly increases

Engineering Contradiction:

Improveimaging qualityVSAvoidoverall size

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The patent employs aspheric surfaces on all three lens elements, changing the geometric parameters from traditional spherical surfaces. This allows for more compact lens design while maintaining superior aberration correction. The aspheric surfaces enable better control of light paths, reducing the overall length requirement while achieving high imaging quality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a combination of different materials: the first lens element uses glass or plastic, while the second and third elements use plastic materials. This composite material approach allows for optimized optical performance with reduced weight and size, as plastic materials can be molded into complex aspheric shapes more easily and at lower cost than glass.

Inventive Principle:

Principle #40Composite materials

3Length of stationary object

If all three lens elements have positive refractive power to miniaturize the lens assembly, then the total length is reduced, but chromatic aberration correction becomes difficult and imaging quality deteriorates

Engineering Contradiction:

Improvetotal lengthVSAvoidchromatic aberration correction

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent uses the second and third lens elements with negative refractive power to counterbalance the chromatic aberration introduced by the first positive lens element. This alternating sign configuration (positive-negative-negative) creates a balanced optical system where the negative elements compensate for the chromatic dispersion of the positive element, achieving effective chromatic aberration correction in a compact form.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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

The lens system achieves enhanced imaging quality, reduced spherical aberration, and miniaturization while maintaining a balanced refractive power allocation, effectively correcting chromatic aberration and maintaining a compact form factor.

Implementation Method 1

The object-side surface and the image-side surface are aspheric

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

reduced spherical aberration

Methodology Applied

Scientific EffectSpherical aberration correction: Lens

Implementation Method 3

correcting chromatic aberration

Methodology Applied

Scientific EffectChromatic aberration correction: Lens

Data Source

PatentUS8724235B2Photographing lens system

Publication Date: 2014.05.13 LARGAN PRECISION

AI summary

A photographing lens system includes, in order from an object side to an image side, a first lens element with positive refractive power including a convex object-side surface and a convex image-side surface, and the object-side surface and the convex image-side surface of the first lens element being aspheric; a second lens element with negative refractive power including a concave object-side surface and a convex image-side surface, and the object-side surface and the image-side surface of the second lens element being aspheric; and a third lens element with negative refractive power including an object-side surface and a concave image-side surface, and the object-side surface and the image-side surface of the third lens element being aspheric. The second lens element and the third lens element are made of plastic. The image-side surface of the third lens element is concave near an optical axis and convex away from the optical axis.