Fixed Focal Length Imaging Optical System Aberration Correction

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Solution Overview

Problem

Existing fixed focal length imaging optical systems face challenges in effectively correcting various aberrations while maintaining a compact design and achieving high image quality, especially in wide-angle lenses, where aberration correction and downsizing are compromised.

Innovation Solution

A fixed focal length imaging optical system configuration with a first lens group having negative power, a second lens group with positive power that moves along the optical axis for focusing, and a third lens group with negative power that remains stationary, optimizing the relationships between total optical length, lens thickness, and focal length to achieve improved aberration correction and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a fixed focal length imaging optical system uses a compact design with limited lens groups, then the device size is reduced, but the ability to correct various aberrations deteriorates

Engineering Contradiction:
Improveoptical system sizeVSAvoidaberration correction performance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The optical system is divided into three distinct lens groups with specific power distributions (positive, positive, negative). Each group is positioned at different distances from the image plane and performs specialized functions: the first two groups contribute to focusing and positive power, while the third group provides negative power for aberration correction. This segmentation allows compact sizing while maintaining aberration correction capability through optimized group placement and power distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The third lens group is specifically designed with negative refractive power and positioned at a greater distance from the image plane compared to the other groups. This local specialization of the third group's optical properties (negative power) and position creates a distributed aberration correction mechanism that enhances overall system performance without increasing total system volume proportionally.

Inventive Principle:
Principle #3Local quality

2Reliability

If the third lens group is positioned farther from the image plane, then aberration correction improves, but the total optical length increases

Engineering Contradiction:
Improveaberration correction performanceVSAvoidoptical length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The system optimizes the ratio relationship between the optical distances of the three lens groups from the image plane. By establishing specific ratio constraints (0.3 < distance1/distance3 < 1.0 and 0.1 < distance2/distance3 < 0.7), the patent achieves a balanced configuration where the third group's distance provides sufficient aberration correction while the overall distance relationships prevent excessive total optical length. This parameter optimization resolves the contradiction between correction performance and compactness.

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 allows for effective correction of aberrations, including coma and image surface curvature, while maintaining a compact design, suitable for wide-angle lenses and enabling precise focusing control without excessive lens barrel length.

Implementation Method 1

a first lens group G1 having positive power, a second lens group G2 having positive power, and a third lens group G3 having negative power in order from an object side toward an image side

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3650902B1Single focus image pickup optical system, and image pickup device and camera system using single focus image pickup optical system
Publication Date: 2024.09.04 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3650902B1 patent drawingFigure 1
  • EP3650902B1 patent drawingFigure 2
  • EP3650902B1 patent drawingFigure 3

AI summary

A fixed focal length imaging optical system includes first lens group (G1) having positive power, second lens group (G2) having positive power, and third lens group (G3) having negative power in order from an object side toward an image side. Upon focusing, second lens group (G2) moves along an optical axis, and first lens group (G1) and third lens group (G3) do not move. The present disclosure provides the fixed focal length imaging optical system capable of favorably correcting various aberrations such as spherical aberration, astigmatism, and distortion, and an imaging device and a camera system each of which includes the fixed focal length imaging optical system.