Surgical Microscope Optical System Chromatic Aberration Compensation

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Solution Overview

Problem

Conventional surgical microscopes face challenges in achieving good imaging quality across both visible and infrared spectral ranges without significant chromatic aberrations, which affect image sharpness and require adjustments in the optical system.

Innovation Solution

The optical system incorporates a second optics assembly with lenses made from specific glasses that compensate for longitudinal chromatic aberrations in the wavelength range of 625 nm to 850 nm, ensuring that images remain sharp across these spectral ranges without needing to adjust the optical assemblies' positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional achromatic optical assemblies are used, then imaging quality in visible spectral range is maintained, but longitudinal chromatic aberration increases in infrared spectral range

Engineering Contradiction:
Improveimaging qualityVSAvoidlongitudinal chromatic aberration
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by modifying the optical system to include specific lens elements with anomalous partial dispersion properties. The second optical assembly incorporates lenses made from glasses with specific optical parameters (anomalous partial dispersion) that compensate for the longitudinal chromatic aberration in the infrared range, while maintaining visible range performance. This changes the physical parameters of the optical system to achieve multi-spectral correction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining different glass types with specific optical properties in the optical assemblies. The second optical assembly uses lenses made from glasses with anomalous partial dispersion (such as fluorophosphate glasses) combined with other optical elements. This composite approach allows the system to correct chromatic aberrations across both visible and infrared spectral ranges by leveraging the complementary properties of different materials.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If optical assemblies are adjusted over long displacement paths to compensate chromatic aberration, then image sharpness in infrared range improves, but device complexity and operation difficulty increase

Engineering Contradiction:
Improveimage sharpnessVSAvoidoptical system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-correcting the chromatic aberration through the specific design of the second optical assembly. The lenses with anomalous partial dispersion are positioned and configured in advance to automatically compensate for longitudinal chromatic aberration in the infrared range. This eliminates the need for post-adjustment or complex displacement mechanisms, as the correction is built into the optical design itself.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the distance of optical system from object area is changed for refocusing, then image quality in visible range is maintained, but object distance consistency is lost

Engineering Contradiction:
Improveimage qualityVSAvoidobject distance consistency
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by using lenses with anomalous partial dispersion properties in the second optical assembly. These special optical parameters allow the system to maintain focus across different spectral ranges (visible and infrared) without changing the object distance. The specific refractive index and dispersion characteristics of the glass materials enable simultaneous optimization for multiple wavelengths.

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 solution allows for clear imaging of the object area in both visible and infrared ranges at the same object distance, reducing chromatic aberrations and maintaining image sharpness without requiring long displacement paths or refocusing.

Implementation Method 1

The second optical assembly 24 is designed as a system that at least partially compensates for longitudinal chromatic aberrations of the first optical assembly 18 occurring in the wavelength range of light 625 nm≤λ≤850 nm

Methodology Applied
Scientific EffectChromatic aberration compensation: Refraction

Data Source

PatentEP3064980B1Optical system and operation microscope
Publication Date: 2020.04.15 CARL ZEISS MEDITEC AG
  • EP3064980B1 patent drawingFigure 1
  • EP3064980B1 patent drawingFigure 2~3
  • EP3064980B1 patent drawingFigure 4~5

AI summary

The invention relates to an optical system for imaging an object region (12) with an optical beam path (16r, 16r') in an image plane (27a, 27b, 27c) of an image acquisition system. The optical system comprises a first optical assembly (18) penetrated by the optical beam path (16r) and a second optical assembly (24) arranged in the optical beam path (16r) on the side of the first optical assembly (18) facing away from the object region (12). According to the invention, the second optical assembly (24) is designed as a system that at least partially compensates for longitudinal chromatic aberrations of the first optical assembly (18) occurring in the wavelength range of light 625 nm ≤ λ ≤ 850 nm.