Microscope Objective-Lens Autofocus With Piezoelectric-Motor Travel
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Solution Overview
Problem
Existing microscope systems face challenges in performing auto-focus control during tiling imaging of cultivation containers due to fabrication tolerances and variations in the bottom surface thickness, which limits the movement of the imaging optical system using piezoelectric elements, especially when large variations are present.
Innovation Solution
A microscope apparatus and program that utilize a combination of a piezoelectric element and a pulse motor to move the objective lens in the optical axis direction, with a controller determining power distribution based on distance and position information to maintain focus across different regions, even when piezoelectric element deformation limits are reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a piezoelectric element is used to move the objective lens in the optical axis direction for high-speed scanning, then the imaging speed is improved, but the movable range is limited due to the deformation limit of the piezoelectric element
Solution Approach 1:
The movable range control unit divides the total movement range into multiple sections, with the piezoelectric element handling fine adjustments within its deformation limit and the pulse motor handling larger displacements. This segmentation allows the system to achieve both high-speed scanning (via piezoelectric element) and extended movable range (via pulse motor).
Solution Approach 2:
The movable range control unit acts as an intermediary that coordinates between the piezoelectric element and pulse motor. It determines when to use each actuator based on the required displacement, enabling the system to overcome the piezoelectric element's deformation limit while maintaining high-speed performance.
2Ease of manufacture
If the focal position is set with reference to the bottom surface of the cultivation container, then the setup is simplified, but imaging quality deteriorates due to fabrication tolerances and thickness variations
Solution Approach 1:
The system uses feedback from the bottom surface position detection unit to dynamically adjust the focal position. By detecting actual thickness variations and communicating this information to the movable range control unit, the system compensates for fabrication tolerances and maintains optimal focus despite variations in container bottom surface.
Solution Approach 2:
The system performs preliminary detection of the bottom surface position before imaging begins. This advance measurement allows the movable range control unit to pre-calculate the required adjustments to the objective lens position, ensuring that focus is optimized for each specific region before the imaging process starts.
3Measurement precision
If high-magnification imaging is performed across the entire observation target, then the image detail is improved, but the observation time increases due to the need to scan multiple regions
Solution Approach 1:
The system dynamically adjusts the scanning strategy based on detected bottom surface variations. Regions with large thickness variations are scanned more efficiently using the pulse motor for rapid positioning, while regions with minimal variations use the faster piezoelectric element, optimizing the balance between image detail and observation time.
Solution Approach 2:
The system performs preliminary scanning to detect bottom surface positions across different regions before conducting detailed high-magnification imaging. This preliminary information allows the system to plan the most efficient scanning path and focus adjustments, reducing unnecessary movements and minimizing observation time while maintaining image quality.
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 effective auto-focus control that follows the position of each region in the optical axis direction, ensuring clear imaging across varied cultivation container surfaces, thereby improving the quality of high-magnification wide-view images.
Implementation Method 1
a piezoelectric element is used as an optical axis direction moving member
Implementation Method 2
a pulse motor that moves the objective lens in the optical axis direction when a deformation amount of the piezoelectric element reaches a limit
Data Source
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AI summary
Provided are a microscope apparatus capable of executing auto-focus control that appropriately follows a high-speed scan in a case of capturing a high-magnification and wide view image of an observation target contained in a container having large variations in the bottom surface, and a program. In a case where a microscope apparatus main body 10 scans the bottom surface of the cultivation container 50 by synchronously controlling a piezoelectric element 15A and an actuator 15B serving as optical axis-directional transport devices having different properties from each other, an objective lens 14b of the imaging optical system 14 is transported to a focus position in the optical axis direction.