Wide-Angle Lens Miniaturization via Aberration Correction

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Solution Overview

Problem

Conventional wide-angle lenses for in-vehicle cameras face challenges in miniaturization due to limited space and difficulties in effectively correcting aberrations such as curvature of field, chromatic aberration of magnification, and coma, especially when the combined effective focal length of the first and second lenses is not within the optimal range.

Innovation Solution

The design of a wide-angle lens comprising a specific arrangement of lenses with varying refractive powers and surface curvatures, including a negative lens with a convex object-side surface and a concave image-side surface, a positive lens with aspherical surfaces, and a cemented lens group, optimized to achieve a combined effective focal length and image height ratio that allows for miniaturization while maintaining good optical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the combined effective focal length of the first and second lenses is not within the optimal range, then the lens can be made smaller, but aberrations such as curvature of field, chromatic aberration of magnification, and coma cannot be effectively corrected

Engineering Contradiction:

Improvelens sizeVSAvoidaberration correction

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the combined effective focal length of the first and second lenses to a specific range (−0.400 ≤ f12/HOI < −0.100). This parameter optimization simultaneously achieves miniaturization of the lens while ensuring effective correction of various aberrations including curvature of field, chromatic aberration of magnification, and coma.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If conventional lens arrangements are used, then the lens structure is simpler, but the object-to-image distance cannot be reduced for miniaturization

Engineering Contradiction:

Improvelens sizeVSAvoidlens arrangement

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the lens system into seven distinct lenses with specific refractive power arrangements (−−+++−+). This segmentation allows for optimized optical performance and miniaturization while managing the complexity through structured arrangement. The diaphragm is also strategically positioned to further divide and control the optical path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies the nesting principle by cementing the sixth and seventh lenses together to form a combined lens unit. This nesting reduces the overall object-to-image distance and compact the lens structure, achieving miniaturization while maintaining optical performance.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Reliability

If the number of lenses is increased to correct aberrations, then optical performance improves, but the lens becomes larger and more complex

Engineering Contradiction:

Improveaberration correctionVSAvoidlens size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent optimizes the refractive powers of individual lenses and their spacing to achieve effective aberration correction with a compact seven-lens structure. By carefully controlling parameters such as the combined effective focal length ratio and surface curvatures, the patent achieves both miniaturization and high optical performance without requiring additional lenses.

Inventive Principle:

Principle #35Parameter changes

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 reduces the object-to-image distance, enabling the miniaturization of the wide-angle lens while effectively correcting curvature of field, chromatic aberration of magnification, and coma, resulting in improved optical performance.

Implementation Method 1

a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and an imaging element

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS11789240B2Wide-angle lens including seven lenses of −−+++−+ refractive powers

Publication Date: 2023.10.17 SANKYO SEIKI MFG CO LTD

AI summary

A wide-angle lens is provided. The wide-angle lens includes, sequentially arranged from an object side, a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a fifth lens, a sixth lens, a seventh lens and an imaging element. The first lens is a negative lens with a convex spherical surface facing the object side and a concave surface facing an image side. The second lens is a negative lens with a concave surface facing the image side. A combined effective focal length of the first lens and the second lens is set to f12 and a maximum image height is set to HOI, −1.000<f12/HOI<−0.400 is satisfied.