Autofocus Device with Projection State Changing Unit for Real-Time Follow-AF
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Solution Overview
Problem
Conventional autofocus systems in microscopes face challenges in maintaining focus when the in-focus position set by the autofocus function differs from the observer's intended observation point, particularly with high numerical aperture objective lenses and thin samples, requiring manual offset adjustments and complex hybrid AF setups.
Innovation Solution
An autofocus device with a stage and objective lens system that includes a driving unit, light casting unit, detection unit, projection state changing unit, and in-focus state determination and adjustment units, allowing real-time follow-AF to the user's desired observation point by controlling the relative positions of the stage and objective lens, and storing settings for precise focus maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional autofocus systems are used with high numerical aperture objective lenses, then high magnification is achieved, but the focus depth becomes very small (sub microns) causing the in-focus position to differ from the observation target position
Solution Approach 1:
The patent replaces manual mechanical focus adjustment with an automated offset control system. The offset control unit automatically adjusts the focus position based on detection unit feedback, eliminating the need for manual mechanical intervention to align the in-focus position with the observation target position.
Solution Approach 2:
The patent introduces an offset parameter that can be adjusted to change the focus position relative to the observation target. By modifying this parameter, the system adapts the focus depth and position to match the specific requirements of thin samples observed with high numerical aperture lenses.
2Measurement precision
If manual offset adjustments are made to align focus with observation target, then focus accuracy is improved, but operation complexity increases and real-time follow-AF capability is lost
Solution Approach 1:
The detection unit continuously monitors the focus state and automatically feeds back to the offset control unit, which adjusts the focus position without user intervention. This self-service mechanism maintains focus accuracy while eliminating complex manual operations.
Solution Approach 2:
The system implements a feedback loop where the detection unit continuously provides information about the current focus state, and the offset control unit uses this feedback to automatically adjust the focus position, maintaining alignment with the observation target in real-time.
3Adaptability or versatility
If hybrid AF setups are used to maintain focus on different positions, then focus flexibility is improved, but device complexity and user intervention requirements increase
Solution Approach 1:
The offset control unit serves multiple functions: it adjusts focus position, maintains real-time follow-AF capability, and adapts to different sample types and observation requirements. This single multi-functional unit replaces the need for complex hybrid AF setups with multiple specialized components.
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 accurate and efficient real-time follow-AF to the user's desired observation point with minimal user intervention, simplifying operations and maintaining focus without manual adjustments, while allowing for storage and retrieval of optimized focus settings.
Implementation Method 1
detection unit for detecting an optical image formed by light that was cast by the lighting unit and was reflected from the sample via the objective lens
Implementation Method 2
projection state changing unit being provided in an optical path from the lighting unit to the detection unit, for changing a state of the optical image projected onto the detection unit
Data Source
AI summary
An autofocus device, comprises: a stage for mounting a sample; an objective lens; a focusing unit driving stage or the objective lens in an optical axis direction in order to control the position relative to each other of the stage and the objective lens; a lighting unit onto the sample; a detection unit detecting an optical image; a projection state changing unit being provided in an optical path, changing a state of the optical image projected onto the detection unit; a first in-focus state determination unit determining an in-focus state of the sample on the basis of a detection result; and a first in-focus state adjustment unit controlling a position of the projection state changing unit such that a state in which the stage and the objective lens are held at prescribed positions under control of the driving unit is determined to be an in-focus state.