Chromatic Confocal Sensor for Well Plate Autofocus
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Solution Overview
Problem
Automated systems for imaging biological samples in well plates face inefficiencies due to the time-consuming process of refocusing cameras for each well, especially when visual contrast is insufficient, and existing methods may not accurately account for non-flat or bowed well bases.
Innovation Solution
A method and apparatus using polychromatic light to measure the position of the base surfaces of well plates, allowing for rapid determination of the focal plane by focusing different wavelengths along an axis and collecting scattered light to adjust the focal plane for accurate imaging across multiple wells without the need for conventional autofocus techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional autofocus techniques are used to focus the camera on each well, then the focal plane can be adjusted for each sample location, but the process is time-consuming and reduces imaging efficiency
Solution Approach 1:
The patent applies preliminary action by pre-calibrating the relationship between wavelength and position along the optical axis before actual imaging. The chromatic confocal sensor pre-determines the position of the well base intersection with the optical axis, allowing the focal plane to be rapidly adjusted without time-consuming conventional autofocus procedures for each well.
2Measurement precision
If the base of the well plate is non-flat or bowed, then standard focusing methods may not accurately locate the focal plane, but adjusting focus for each well individually increases processing time
Solution Approach 1:
The patent applies segmentation by dividing the well base into multiple measurement points along the optical axis, each corresponding to a specific wavelength. By measuring the position at multiple discrete wavelength points and interpolating, the system accurately determines the intersection position even when the base is non-flat or bowed, without requiring manual refocusing for each well.
3Reliability
If visual contrast between samples and surroundings is insufficient, then conventional autofocus systems cannot function efficiently, but alternative methods are needed that do not rely on visual contrast
Solution Approach 1:
The patent introduces an intermediary measurement approach by using a chromatic confocal sensor that measures the position of the well base through optical wavelength-position relationships rather than relying on visual contrast. This intermediary measurement system enables reliable focal plane determination even when samples have insufficient visual contrast for conventional autofocus systems.
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 approach significantly reduces the time required for imaging multiple wells by allowing simultaneous focus adjustment across all positions, improving efficiency and accuracy by using pre-calibrated relationships between wavelengths and positions to determine the base intersection with the optical axis.
Implementation Method 1
focusing a continuum of wavelengths of polychromatic light to a continuum of pre-calibrated positions along an axis that extends through where the base of a biological sample container arranged in the container station would be, and by collecting, preferably confocally, and spectrally decomposing those components of the polychromatic light scattered from said axis
Implementation Method 2
collecting, preferably confocally, and spectrally decomposing those components of the polychromatic light scattered from said axis
Data Source
AI summary
An apparatus and method for optically analyzing samples in a biological sample container containing samples arranged at different locations on the base of the container. An optical acquisition device is provided comprising a detector and an objective. The position of the upper and lower surfaces of the base at each of the sample locations is determined by a confocal polychromatic displacement sensor. Light is collected from each of the sample locations by adjusting the focal plane to be coincident with, or vertically offset from, the upper surface of the base, as determined from the displacement sensor. This allows for rapid scanning of large numbers of samples in a multi-well plate or other biological sample containers.