Optical Imaging System Reducing Optics Abbe Number Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing optical imaging systems, such as surgical microscopes, face challenges in achieving optimal image quality and a compact design for wide-angle viewing, with issues like reduced imaging quality and increased overall length due to the introduction of reducing optics.

Innovation Solution

The optical imaging system employs lenses made of materials with specific Abbe numbers, where the first lens has a higher Abbe number than the second, ensuring a chromatic angular deviation of less than 0.5' across the 480-660 nm wavelength range, and allows for adjustable focusing and compact design by enabling the reducing optics to be swiveled into the beam path.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If reducing optics are introduced into the beam path to enable wide-angle viewing, then the adaptability of the optical imaging system is improved, but the image quality deteriorates due to reduced imaging quality

Engineering Contradiction:
Improveadaptability of optical imaging systemVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent changes the material parameters (Abbe numbers) of the lens elements in the reducing optics. Specifically, it uses a first lens with a first Abbe number and a second lens with a second Abbe number, where the difference between these Abbe numbers is between 16 and 22. This parameter change allows the system to achieve both wide-angle viewing capability and acceptable image quality by controlling chromatic aberrations through the specific combination of materials with different dispersion properties.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If reducing optics are introduced into the beam path to enable wide-angle viewing, then the adaptability of the optical imaging system is improved, but the overall length increases

Engineering Contradiction:
Improveadaptability of optical imaging systemVSAvoidoverall length
Core Design Contradiction:
Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent optimizes the optical parameters of the reducing optics, specifically the focal lengths and Abbe numbers of the lens elements. By carefully selecting the focal lengths and material properties, the design achieves a compact configuration that provides the necessary beam path reduction for wide-angle viewing while minimizing the overall length of the optical system, making it suitable for surgical applications where space is limited.

Inventive Principle:
Principle #35Parameter changes

3Length of moving object

If the distance between the main lens and the object is reduced to achieve compact design, then the overall length is reduced, but the focal lengths for wide-angle lenses become very small which deteriorates image quality

Engineering Contradiction:
Improveoverall lengthVSAvoidimage quality
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs a composite lens system in the reducing optics, combining lens elements made of different materials with distinct Abbe numbers (difference between 16 and 22). This composite approach allows the system to achieve the required short focal lengths for compact design while using the different material properties to correct chromatic aberrations and maintain image quality. The combination of materials with different dispersion characteristics compensates for the optical deficiencies introduced by the short focal lengths.

Inventive Principle:
Principle #40Composite materials

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 ensures consistently good contrast and image quality over the entire wavelength range with minimal chromatic angular deviation, allowing for a compact and versatile optical imaging system suitable for wide-angle viewing applications.

Implementation Method 1

The first lens of the reducing optics is made of a first material that has a first Abbe number, and that the second lens of the reducing optics is made of a second material that has a second Abbe number

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

the difference between the first Abbe number and the second Abbe number is between 16 and 22... the image quality for an observation beam path is so good that contrast-reducing and disturbing image errors are corrected

Methodology Applied
Scientific EffectChromatic aberration correction: Dispersion (of waves)

Data Source

PatentEP2853933B1Optical imaging system
Publication Date: 2019.05.22 CARL ZEISS MEDITEC AG
  • EP2853933B1 patent drawingFigure 1
  • EP2853933B1 patent drawingFigure 2
  • EP2853933B1 patent drawingFigure 3

AI summary

Optical imaging system (1) for generating an image of an object plane with a lens system comprising a principal objective (20) and a reducing optic in front of the principal objective (20), and aligned along an optical axis 23. The reducing optic has a first lens (22) with a positive refractive power (22) and a second lens (21) with a negative refractive power. An object-side first principal plane (H) and an image-side second principal plane (H') are defined by the lens system. The optical imaging system defines an observation beam path that is guided through the lens system such that the observation beam path in the first principal plane (H) and in the second principal plane (H') is at a distance B from the optical axis of the lens system.According to the invention, the first lens (22) is made of a first material having a first Abbe number, and the second lens (21) is made of a second material having a second Abbe number, wherein the first Abbe number is greater than the second Abbe number. The lens system is configured such that for a wavelength range λ of 480 nm ≤ λ ≤ 660 nm and for a principal wavelength e = 546 nm, the following relationship is satisfied: arctanBfe⁢ʹ+fe⋅fe⁢ʹ/fλ-fe<0.5⁢ʹ, where: fe = object-side focal length for the principal wavelength e with respect to the first principal plane (H); fλ = object-side focal length for the wavelength λ with respect to the first principal plane (H); fe' = image-side focal length for the principal wavelength e with respect to the second principal plane (H').