Wide-Angle Lens Aspheric Correction Miniaturization

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Solution Overview

Problem

Existing wide-angle lenses face challenges in achieving a miniaturized form with an angular range exceeding 180 degrees due to limitations in cost reduction, miniaturization, and image quality issues such as chromatic aberration and image degradation caused by manufacturing errors and environmental changes, particularly when using plastic lenses with limited refractive index and Abbe number range.

Innovation Solution

A wide-angle lens configuration comprising a front lens group with at least two positive power lenses and one negative power lens, and a rear lens group with a positive power lens, including aspheric surfaces to minimize aberrations, combined with an electronic circuit for signal processing to correct distortion, chromatic aberration, and modulation transfer function characteristics, using glass lenses for the strongest power to enhance stability and reduce environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If plastic lenses with limited refractive index and Abbe number range are used to reduce cost and miniaturize the lens, then manufacturing cost and lens size are reduced, but chromatic aberration of magnification cannot be adequately corrected and color fringing occurs

Engineering Contradiction:

Improvemanufacturing costVSAvoidchromatic aberration correction

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a composite lens structure combining plastic lenses with at least one glass lens having specific refractive index and Abbe number characteristics. This composite approach allows the system to achieve both cost reduction (through plastic lenses) and adequate chromatic aberration correction (through the glass lens with suitable optical properties).

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent specifies particular ranges for refractive index and Abbe number of the glass lens to optimize chromatic aberration correction. By carefully selecting and controlling these optical parameters, the system achieves effective correction of chromatic aberration of magnification while maintaining a miniaturized structure.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If multiple aspheric surface lenses are used to achieve miniaturization and weight reduction, then lens size and weight are reduced, but image degradation occurs due to assembling errors in manufacturing or environmental changes

Engineering Contradiction:

Improvelens sizeVSAvoidimage quality stability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies aspheric surfaces selectively rather than on all lenses, concentrating the aspheric correction where most needed while using spherical surfaces on other lenses. This reduces the number of surfaces requiring precise manufacturing and assembly, thereby improving reliability and reducing sensitivity to assembly errors while still achieving miniaturization.

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If the object side lens (first lens) has a relatively large radius to simplify manufacturing, then ease of manufacture is improved, but the lens thickness cannot be adequately reduced which becomes an obstacle to reducing the size of the image capturing lens

Engineering Contradiction:

Improvelens manufacturing simplicityVSAvoidlens thickness

Core Design Contradiction:

Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent divides the lens system into multiple lens elements with different functions. The first lens can have a larger radius for ease of manufacture, while subsequent lenses compensate for the thickness through their combined optical power and positioning, achieving overall size reduction without sacrificing manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

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 solution enables a high-quality, miniaturized image capturing apparatus with an angular range exceeding 180 degrees, effectively correcting optical aberrations and maintaining image quality under varying conditions, while reducing manufacturing costs and environmental sensitivity.

Implementation Method 1

one of the lenses of the front lens group arranged second in order from the object side has a lens face arranged into an aspheric surface

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

chromatic aberration of magnification may not be adequately corrected and color fringing may easily occur

Methodology Applied

Scientific EffectChromatic aberration:

Data Source

PatentUS7773305B2Wide-angle lens and image capturing apparatus

Publication Date: 2010.08.10 RICOH CO LTD

AI summary

A wide-angle lens is disclosed that includes a front lens group and a rear lens group that are arranged in order from an object side to an image side with an aperture being arranged between the front lens group and the rear lens group. The front lens group includes at least two lenses arranged toward the object side that have negative powers, and at least one lens arranged toward the image side that has a positive power. The rear lens group includes at least one lens having a positive power. One of the lenses of the front lens group arranged second in order from the object side has a lens face that is arranged into an aspheric surface. The front lens group, the aperture, and the rear lens group make up an image forming system having an angle of view greater than 180 degrees.