Single-Objective Stereo Microscope With Split-Aperture Image Correction

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Solution Overview

Problem

Existing stereoscopic microscopes face challenges in achieving high magnification and resolution due to the use of separate objective assemblies, which result in reduced aperture size and exit pupil size, making them impractical for comfortable viewing and limiting optical performance.

Innovation Solution

A stereo microscope design utilizing a split aperture stop structure within a single objective assembly, combined with a digital image processor to compensate for image distortions and intensity variations, allowing for adjustable transition between stereo and mono views.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate objective assemblies are used to achieve stereo perception, then depth perception is improved, but aperture size and exit pupil size are reduced, limiting resolution and making viewing uncomfortable

Engineering Contradiction:
Improvedepth perceptionVSAvoidaperture size
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The aperture stop is divided into two separate aperture stops, each directing light to a different eyepiece. This segmentation allows each eye to receive light from a slightly different angle through the same objective assembly, providing stereo perception without requiring separate objectives, thereby maintaining large aperture size and exit pupil dimensions for high resolution and comfortable viewing

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines the functions of separate objective assemblies into a single objective assembly by using a split aperture stop. The single objective produces an intermediate image that is then divided by the split aperture and directed to both eyepieces, merging the stereo separation function into the aperture rather than requiring separate objectives, thus maintaining large aperture size while achieving stereo perception

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If separate objective assemblies are used to achieve stereo perception, then depth perception is improved, but the working distance must be large to accommodate the bulky objectives, reducing versatility

Engineering Contradiction:
Improvedepth perceptionVSAvoidworking distance
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent merges the stereo separation function into the aperture stop rather than requiring separate objective assemblies. This allows the use of a single compact objective assembly with a large working distance, while the split aperture directs light to different eyepieces to provide stereo perception, thereby achieving both depth perception and versatile short working distance

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The aperture stop is segmented into two separate aperture stops positioned at different locations. This segmentation enables stereo perception through the same objective assembly, eliminating the need for bulky separate objectives and allowing the objective to be positioned close to the object for versatile applications

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If a single objective assembly is used with split aperture, then aperture size and resolution are improved, but the optical paths become asymmetric, causing image distortion and intensity variations

Engineering Contradiction:
Improveaperture sizeVSAvoidoptical path symmetry
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

A digital image processor is implemented to detect and correct asymmetries in the optical paths. The processor receives images from both eyepieces, analyzes intensity variations and distortions caused by the asymmetric split aperture configuration, and applies computational corrections to equalize the images, thereby maintaining the benefits of large aperture size while compensating for optical path asymmetries

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses a digital image processor to dynamically adjust image parameters such as intensity and geometric distortion. By applying computational corrections based on the known asymmetric optical path characteristics, the system compensates for the asymmetries introduced by the split aperture, maintaining image quality while preserving the advantages of a large single aperture

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

The design achieves higher resolution and comfortable viewing by maintaining stereo perception while allowing for seamless transitions between stereo and mono modes, enhancing user experience and optical performance.

Implementation Method 1

The objective assembly 101 is configured such that it produces an image of the object 111 at infinity

Methodology Applied
Scientific EffectOptical focusing: Lens

Implementation Method 2

A tube lens 103 focusses light from the objective assembly 101 to produce an intermediate image 112 within the microscope

Methodology Applied
Scientific EffectOptical focusing: Lens

Implementation Method 3

A beamsplitter 221 is provided within the microscope tube, splitting the light along two paths

Methodology Applied
Scientific EffectLight splitting: Reflection

Implementation Method 4

An eyepiece 104 magnifies the intermediate image 112, producing a larger virtual image

Methodology Applied
Scientific EffectOptical magnification: Lens

Data Source

PatentEP3695264B1Stereo microscope with single objective
Publication Date: 2025.07.16 VISION ENG LTD
  • EP3695264B1 patent drawingFigure 1~4B
  • EP3695264B1 patent drawingFigure 5
  • EP3695264B1 patent drawingFigure 6A~7C

AI summary

An assembly for use in a microscope having an objective assembly including an aperture. The assembly comprises a lens and a beamsplitter. The lens and the beamsplitter are configured to form a respective aperture image on each of two optical paths. The assembly further comprises, on each optical path, a stop structure. Each stop structure is located on a plane of the respective aperture image, so as to block a portion of the respective aperture image in order to provide an exit pupil, such that a stereoscopic image of an object viewed through the microscope is produceable by the combination of the images of the object visible through each exit pupil. The assembly further comprises two image sensors and a digital image processor. Each image sensor is configured to capture an image visible through the respective exit pupil and to output a digital image. The digital image processor is configured to apply a correction to the respective digital image output by each image sensor, the correction being based on the position of the respective stop structure