Microscope Optical Path Difference for Focus Accuracy
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Solution Overview
Problem
Conventional microscope systems face challenges in securing sufficient light for image capture and achieving high focus accuracy due to the division of light in optical path difference systems, which affects the timing and accuracy of image pickup.
Innovation Solution
An image capturing apparatus with a stage, light source, and a light guiding optical system that includes a light dividing unit to separate optical paths for image capture and focus control, using an optical path difference producing member on the second optical path to maintain light intensity and allow for accurate focus control without dividing light, and a region control unit to set waiting times based on scanning speed and interval between imaging regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light dividing unit is used to separate optical paths for image capture and focus control, then focus control capability is improved, but light intensity for image capture is reduced
Solution Approach 1:
The optical path is divided into two separate paths: a first optical path for image capture and a second optical path for focus control. The light dividing unit (beam splitter) segments the incoming light from the sample, directing portions to different imaging devices. This allows independent optimization of each path without compromising the other.
Solution Approach 2:
A light guiding optical system with a beam splitter acts as an intermediary to distribute light between the image capture path and the focus control path. The beam splitter mediates the light distribution, enabling both functions to operate simultaneously with adequate light intensity in each path.
2Illumination intensity
If exposure time is extended to secure sufficient light for image capture, then light intensity is improved, but image capture speed is reduced
Solution Approach 1:
By segmenting the optical path and using a beam splitter, the system captures images in both the first and second optical paths simultaneously with sufficient light intensity, eliminating the need for extended exposure times that would slow down image capture.
3Reliability
If timing for image capture by first and second imaging units is synchronized, then system coordination is improved, but device complexity is increased
Solution Approach 1:
The timing control unit merges the control of both imaging devices into a unified timing system. It coordinates the exposure timing of the first imaging device (for image capture) and the second imaging device (for focus control) simultaneously, ensuring synchronized operation while managing complexity through integrated control.
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 solution ensures high accuracy in focus positioning and sufficient light for image pickup, allowing for precise control of the focus position and efficient image capture without reducing light intensity on the second optical path.
Implementation Method 1
an optical path difference producing member which gives an optical path difference to the second optical image along an in-plane direction of the imaging area
Data Source
AI summary
In the image capturing apparatus, the optical path difference producing member is disposed on the second optical path. Thereby, at the second imaging device, it is possible to suppress the amount of light on image pickup of an optical image which is focused at the front of an optical image made incident into the first imaging device (front focus) and on image pickup of an optical image which is focused at the rear thereof (rear focus) and also to secure the amount of light on image pickup by the first imaging device. Further, in the image capturing apparatus, based on a scanning velocity v of the stage and an interval d between the first imaging region and the second imaging region, a waiting time is set from image pickup at the first imaging region to image pickup at the second imaging region. As a result, light from the same position of the sample is made incident into the first imaging region and the second imaging region. Thus, it is possible to control a focus position at high accuracy.