Six-Lens Imaging Optics for Temperature-Stable Focus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging lenses for cameras, particularly those used in monitoring and onboard cameras, face challenges in maintaining focusing performance across varying environmental conditions, while also requiring compact size, light weight, and resistance to temperature changes, with existing technologies struggling to balance these factors effectively.
Innovation Solution
A six-lens imaging lens configuration with specific refractive power distributions and temperature coefficients, along with conditional expressions to optimize lens shapes and materials, ensuring favorable optical performance and reduced focus shift across temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact lens design is used to reduce size, then the lens becomes smaller and lighter, but focusing performance deteriorates under temperature changes
Solution Approach 1:
The patent applies parameter changes by carefully selecting and controlling the temperature coefficients of refractive index (dN/dT) for specific lens elements (fourth and sixth lenses). By setting these parameters within specific ranges and establishing quantitative relationships between dN4/dT, dN6/dT, and focal length f, the design achieves temperature compensation that maintains focusing performance while keeping the lens compact.
2Measurement precision
If lens elements are added to improve optical performance, then focusing accuracy improves, but device complexity increases
Solution Approach 1:
The patent implements multi-functionality by designing a six-lens configuration where each lens element serves multiple purposes. The first three lenses form a negative-positive lens group that provides both imaging and initial aberration correction, while the fourth, fifth, and sixth lenses form another negative-positive combination that simultaneously corrects temperature-induced focus shift and refines optical quality. This integrated design achieves high focusing accuracy without proportionally increasing complexity.
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 proposed lens configuration achieves high optical performance, compactness, and resistance to environmental changes, particularly in temperature fluctuations, while maintaining favorable focusing capabilities.
Implementation Method 1
an imaging lens includes, in order from an object side, a first lens, a second lens, a third lens, an aperture stop, a fourth lens, a fifth lens, and a sixth lens. The first lens has negative refractive power. The second lens has negative refractive power. The third lens has positive refractive power. The fourth lens has positive refractive power. The fifth lens has negative refractive power. The sixth lens has positive refractive power.
Implementation Method 2
temperature coefficient of refractive index of the fourth lens for d-line within a temperature range of 20° C. to 40° C. be dN4/dT: temperature coefficient of refractive index of the sixth lens for the d-line within the temperature range of 20° C. to 40° C. be dN6/dT
Data Source
AI summary
An imaging lens includes, in order from an object side, a first lens having negative refractive power; a second lens having negative refractive power; a third lens having positive refractive power; an aperture stop; a fourth lens having positive refractive power; a fifth lens having negative refractive power; and a sixth lens having positive refractive power. Letting curvature radius of an object-side surface of the first lens be R1; curvature radius of an image-side surface of the first lens be R2; temperature coefficient of refractive index of the fourth lens for d-line within a temperature range of 20° C. to 40° C. be dN4/dT; temperature coefficient of refractive index of the sixth lens for the d-line within the temperature range of 20° C. to 40° C. be dN6/dT; and focal length of the imaging lens for the d-line be f, the imaging lens satisfies conditional expressions:0.6<(R1+R2)/(R1-R2)<0.8(1)-1.1<(dN4/dT+dN6/dT)/f<-0.7(2)