Microscope Depth of Field Determination via F-Stop Projection
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Solution Overview
Problem
Microscopes face challenges in accurately focusing on transparent or low contrast specimens due to the subjective nature of traditional focusing methods and the difficulty in determining the desired depth of field, which results in imaging beyond the area of interest.
Innovation Solution
A microscope system and method that empirically determines the depth of field by projecting an F-stop onto a specimen, analyzing contrast at incremental positions, and adjusting the relative movement between the specimen and objective lens to establish the boundaries of the depth of field, allowing for precise focusing and imaging at a defined depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional subjective focusing methods are used, then the microscope can be operated with simple mechanisms, but the focusing accuracy and precision deteriorate due to human subjectivity
Solution Approach 1:
The patent replaces the mechanical manual focusing system with an automated optical sensing system. A light source projects patterns onto the specimen, and a sensor detects the reflected or transmitted light to objectively determine focus quality, eliminating reliance on human visual judgment and manual adjustment mechanisms.
Solution Approach 2:
The patent implements a feedback loop where the sensor continuously monitors focus quality by analyzing light patterns at different focal planes, and this information is used to automatically adjust the focal position. The system iteratively refines the focus by comparing sensor readings against optimal focus criteria and making real-time adjustments.
2Area of stationary object
If the depth of field is increased to capture more specimen areas, then the imaging coverage is improved, but the imaging precision of specific depths deteriorates due to blur from out-of-focus regions
Solution Approach 1:
The patent divides the three-dimensional specimen into multiple discrete focal planes or depth layers. The system sequentially captures images at each segmented depth plane and can reconstruct a composite three-dimensional representation, allowing precise imaging of specific depths while maintaining the option to synthesize broader coverage through computational methods.
Solution Approach 2:
The patent transitions from two-dimensional planar imaging to three-dimensional volumetric imaging by adding the depth dimension as a discrete variable. The system captures image data across multiple focal planes and uses computational algorithms to reconstruct and display the specimen in three dimensions, enabling selective visualization of specific depth regions while preserving overall structural context.
3Extent of automation
If automated focus systems using light reflection are used, then the focusing automation is improved, but the ability to focus on transparent specimens deteriorates due to insufficient reflectivity
Solution Approach 1:
The patent introduces an intermediary optical element or coating on the specimen or objective lens that enhances light interaction. This intermediary layer increases the contrast between reflected and transmitted light, enabling the automated sensor to reliably detect focal positions on transparent specimens that would otherwise be invisible to reflection-based sensing methods.
4Volume of stationary object
If multiple focal planes are captured to improve depth coverage, then the volumetric imaging is improved, but the imaging time deteriorates due to sequential capture requirements
Solution Approach 1:
The patent employs periodic or pulsed illumination and rapid sequential capture of focal planes. The light source is modulated in a periodic manner, and the system captures multiple depth planes in rapid succession during a single illumination cycle, significantly reducing the total imaging time compared to traditional sequential methods while maintaining complete volumetric coverage.
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
Enables accurate and automated focusing on transparent or low contrast specimens, improving imaging precision by determining the working distance and depth of field, thereby allowing for clear imaging of specific areas within the specimen.
Implementation Method 1
projecting the F-stop onto the focal face at the first position to produce an F-stop projection thereon
Data Source
AI summary
A microscope system and method empirically determines the boundaries of the depth of field of an objective lens. The system and method are largely automated, with the manipulation of a specimen to be imaged being carried out by processors and associated equipment. Calculations of the empirical depth of field are also likewise automated. Upon empirically determining the boundaries of the depth of field, the specimen, particularly when transparent or translucent, can be accurately imaged at user-defined depths smaller than the depth of field.