Microscope Autofocus Control for Culture Containers
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Solution Overview
Problem
Existing microscopes face challenges in accurately focusing on an observation target placement surface within a culture container due to variations in culture container type, culture solution amount, and objective lens magnification, leading to difficulties in separate detection of reflection signals from the target surface and container surfaces.
Innovation Solution
A microscope system with an illumination light emission unit, container support, objective lens, focusing light emission unit, reflected light detection, and autofocus control unit that adjusts focus based on acquired information about the container, culture solution amount, and objective lens magnification, allowing switching between first and second autofocus controls to accurately focus on the observation target placement surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional autofocus control is used to focus on the observation target placement surface, then focus accuracy deteriorates when the container bottom thickness is small or culture solution amount is small, but using alternative methods increases device complexity
Solution Approach 1:
The system changes the wavelength parameter of the light used for focus detection. By using infrared light with a wavelength different from the observation light, the system can detect focus position accurately without being affected by the culture solution or container bottom interference that plagues conventional visible light autofocus methods
Solution Approach 2:
The autofocus control is segmented into multiple modes based on container and culture solution conditions. The control unit selects between first autofocus control (for containers with sufficient bottom thickness and culture solution) and second autofocus control (for containers with small bottom thickness or small culture solution amount), allowing optimized focus detection for each specific condition
2Measurement precision
If the bottom portion thickness of the culture container is small, then focusing on the observation target placement surface becomes difficult due to signal interference, but increasing container thickness increases device complexity
Solution Approach 1:
The system introduces an intermediary substance (infrared light) to detect the focus position. This intermediary wavelength of light can penetrate the culture solution and container bottom without being significantly absorbed or scattered, allowing the detection unit to distinguish the reflection from the observation target placement surface even when the container bottom is thin
3Measurement precision
If the amount of culture solution is small, then the distance between liquid surface and observation target placement surface is short causing detection signal interference, but increasing solution amount increases productivity requirements
Solution Approach 1:
The system changes the detection wavelength to infrared, which has different penetration and reflection characteristics compared to visible light. This parameter change allows the detection unit to differentiate between reflections from the liquid surface and the observation target placement surface even when they are close together, without requiring increased culture solution volume
4Measurement precision
If the magnification of the objective lens is low, then the focal depth is large making precise focusing difficult, but increasing magnification reduces the observation area
Solution Approach 1:
The system replaces the mechanical focusing adjustment process with an optical detection-based autofocus system. The detection unit measures the focus position by analyzing reflected infrared light, and the control unit automatically adjusts the objective lens position, eliminating the need for manual focus adjustment and providing precise focusing regardless of lens magnification
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 precise focusing on the observation target placement surface by adapting autofocus control methods based on container and solution conditions, improving image clarity and focus accuracy regardless of container type, solution amount, and lens magnification.
Implementation Method 1
an objective lens on which the illumination light having passed through the container and the container support unit is incident
Implementation Method 2
an objective lens on which the illumination light having passed through the container and the container support unit is incident
Implementation Method 3
a reflected light detection unit that detects reflected light, which is due to emission of the focusing light from the container support unit side, through the objective lens
Data Source
AI summary
A microscope includes an illumination light emission unit 10 that emits illumination light, a stage 61 on which a culture container 60 is placed, an objective lens 31 on which the illumination light having passed through the culture container 60 and the stage 61 is incident, a focusing light emission unit 70 that emits focusing light, a reflected light detection unit 75 that detects reflected light due to emission of the focusing light, a distance changing unit 34 that changes a distance between the objective lens 31 and the stage 61, an autofocus control unit 51 that performs autofocus control based on the reflected light, and a focus control information acquisition unit 53 that acquires focus control information including information of the culture container 60, the amount of culture solution C, and the magnification of the objective lens 31.