Observation Device Auto-Focus Control Using Displacement Sensors
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Solution Overview
Problem
Current observation devices require excessive time for auto-focus control and scanning, making high-speed imaging of multipotential stem cells impractical due to the need for focal position adjustments in each observation region, especially when using containers with millimeter-order fabrication tolerances.
Innovation Solution
The observation device employs a displacement sensor moving mechanism with a guide mechanism and a piezoelectric element in the imaging optical system to move the objective lens based on detected container positions, allowing for high-speed auto-focus control and reduced scanning time by reciprocating the stage or imaging optical system in both main and sub-scanning directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If auto-focus control is performed for each observation region using conventional methods, then focal position accuracy is improved, but imaging time increases excessively (about 2 seconds per region)
Solution Approach 1:
The patent measures the container bottom position in advance using a displacement sensor before actual imaging begins. This preliminary measurement allows the system to pre-calculate focal positions for all observation regions, eliminating the need for time-consuming auto-focus control during the imaging process itself. The focal position for each region is determined based on the pre-measured container position and the known relationship between container position and focal plane.
Solution Approach 2:
The patent replaces the conventional auto-focus control method (which mechanically adjusts the objective lens position based on image contrast analysis) with a calculation-based approach. Instead of using mechanical feedback from image contrast, the system calculates the focal position directly from the displacement sensor data and geometric relationships, significantly reducing the time required for focus adjustment.
2Productivity
If the stage is moved at high speed to reduce scanning time, then productivity is improved, but the operation process and auto-focus control results may not match, causing imaging errors
Solution Approach 1:
The patent performs all position measurements and focal position calculations before the high-speed scanning begins. The displacement sensor measures the container position in advance, and the control unit calculates all necessary focal positions beforehand. During high-speed scanning, the system simply applies the pre-calculated focal positions without needing to perform real-time auto-focus control, thereby maintaining both high speed and high reliability.
Solution Approach 2:
The patent introduces a displacement sensor as an intermediary device that directly measures the container position without requiring image capture and analysis. This intermediary measurement system provides accurate position data independently of the scanning speed, allowing the system to maintain synchronization accuracy even when scanning at high speeds.
3Measurement precision
If conventional auto-focus control methods are used for each observation region, then focal position accuracy is improved, but the number of motors and device complexity increase
Solution Approach 1:
The patent extracts the auto-focus control function from the imaging system by using a separate displacement sensor to measure the container position independently. This measurement is then used to calculate focal positions without requiring additional motors or complex synchronization systems in the imaging optical system itself. The focus adjustment is achieved through calculation rather than additional mechanical actuators.
Solution Approach 2:
The displacement sensor serves multiple functions: it measures the container position for focus calculation, and its data is used to determine focal positions for all observation regions simultaneously. This single sensor replaces what would otherwise require multiple motors and complex control systems, demonstrating multi-functionality that reduces overall device complexity.
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 enables rapid auto-focus control and significantly shortens the scanning time across multiple observation regions, facilitating high-speed imaging by detecting container positions before image capture and adjusting the focal position accordingly.
Implementation Method 1
the imaging optical system may include a piezoelectric element that moves the objective lens in an optical axis direction
Implementation Method 2
at least one displacement sensor...detects a vertical position of a container
Data Source
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AI summary
Provided are an observation device, an observation method, and an observation control program capable of performing an auto-focus control for each observation region at high speed and shortening a scanning time of each observation region. The observation device includes a stage 51, an imaging optical system 14 that includes an objective lens, a detection section 18 that includes displacement sensors 18a and 18b that detect a vertical position of a cultivation container 50, an imaging optical system controller 21 that controls the imaging optical system driving section 15 to move the objective lens in an optical axis direction on the basis of the vertical position of the cultivation container 50, and a horizontal driving section 17 that moves the stage 51 in a main scanning direction and a sub-scanning direction and reciprocates the stage 51 in the main scanning direction, in which the detection section 18 detects the vertical position of the cultivation container 50 at a forward position in a movement direction of the observation region with reference to the position of the observation region of the imaging optical system 14 with respect to the cultivation container 50, and changes a displacement sensor to be used in accordance with a change of the movement direction in the main scanning direction.