Auto-Focus Displacement Sensor for Cell Imaging
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Solution Overview
Problem
Existing observation devices face challenges in performing high-speed auto-focus control for high-magnification imaging of cells in culture containers due to mechanical inaccuracies in the XY stage, leading to out-of-focus images and prolonged imaging times.
Innovation Solution
An observation device with an imaging optical system, auto-focus displacement sensors, and a vertical direction error acquisition section that precedently detects the vertical position of the container and adjusts the focal length or lens position to compensate for mechanical errors, allowing precise auto-focus control during scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If auto-focus control is performed for each observation position using a displacement gauge, then imaging accuracy is improved, but imaging time increases significantly (about 2 seconds per position, totaling 10 minutes for 300 positions)
Solution Approach 1:
The patent performs auto-focus control in advance at predetermined positions (e.g., four corner positions) before actual imaging. The obtained focus information is then used to calculate and apply focus offsets to all observation positions, eliminating the need for time-consuming per-position auto-focus during imaging.
Solution Approach 2:
The patent copies focus information from predetermined reference positions to all observation positions through calculated offset values. Instead of measuring each position individually, the system creates a focus map by transferring and adapting the focus data from a limited number of reference points across the entire imaging region.
2Area of stationary object
If the XY stage is moved to scan observation positions, then wide-area imaging is enabled, but mechanical inaccuracies cause Z-position variations (undulation) leading to out-of-focus images
Solution Approach 1:
The patent uses displacement gauges to detect actual Z-position variations of the XY stage during scanning. This feedback information is used to calculate focus offsets that compensate for mechanical undulations, allowing the system to maintain focus accuracy across the entire wide imaging area despite stage movement inaccuracies.
Solution Approach 2:
The patent dynamically adjusts focus parameters (lens Z-position or focal length) based on detected stage position variations. By changing focus parameters in response to measured undulations, the system compensates for mechanical inaccuracies and maintains image focus across the full imaging area.
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 high-accuracy auto-focus control and significantly reduces imaging time by compensating for mechanical inaccuracies in the XY stage, facilitating high-speed imaging of cells in culture containers.
Implementation Method 1
auto-focus displacement sensors that precedently detect the vertical position of the container
Implementation Method 2
imaging optical system having an imaging lens that forms an image of an observation target
Data Source
AI summary
Before an observation region of the imaging optical system reaches an observation position in a culture container, a vertical position of the culture container at the observation position is precedently detected by an auto-focus displacement sensor. In a case where an auto-focus control is performed on the basis of the position, an error between the precedently detected vertical position of the container at the observation position and a vertical position of the container at a time point when an observation region of the imaging optical system is scanned up to the observation position is acquired, and an objective lens is moved in an optical axis direction on the basis of the error.