Optical Distance Measuring Apparatus for Live Cell Imaging
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Solution Overview
Problem
Conventional microscopes face challenges in achieving high-resolution three-dimensional measurements of biological samples without damaging them, particularly in live cells, and struggle to accurately measure refractive index distributions and spatial frequencies within the plane.
Innovation Solution
An optical distance measuring apparatus using coherent irradiation light, a scanning element, and photo detectors to obtain phase information and measurement values, allowing for high-resolution two-dimensional scanning and three-dimensional measurement of objects without the need for special modulation elements or acoustic optical devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanning electron microscope is used to achieve high resolution and large focal depth, then measurement precision is improved, but the object under measurement must be coated with conductive material which damages the cell and reduces reliability for live cell observation
Solution Approach 1:
The patent replaces the electron beam-based mechanical scanning system with an optical interference system using coherent light. The heterodyne interference method uses light waves instead of electron beams to probe the sample, eliminating the need for conductive coatings and enabling live cell observation while maintaining high measurement precision through phase detection
2Measurement precision
If a probe microscope is used to measure distance by utilizing atomic force or tunnel current, then measurement precision is improved, but the probe cannot move at high speed and handling becomes difficult
Solution Approach 1:
The patent replaces the mechanical probe system with a non-contact optical interference system. By using heterodyne interference of coherent light beams, the system achieves high-precision distance measurement without physical contact, enabling rapid scanning and real-time measurement without the speed limitations and handling difficulties of mechanical probes
3Measurement precision
If a confocal microscope is used to obtain height information by moving the objective lens, then three-dimensional measurement is achieved, but the measurement cannot be performed in real time due to the need to move components
Solution Approach 1:
The patent employs periodic modulation of the light source frequency to create heterodyne interference signals. This periodic action encodes the optical path difference information directly into the frequency domain, allowing simultaneous measurement of multiple points without mechanical movement, thereby achieving real-time three-dimensional measurement while maintaining height information accuracy
4Measurement precision
If conventional optical heterodyne method is used to measure phase change with resolution of 1/500 of wavelength, then measurement precision is improved, but the method requires two laser lights with different frequencies which increases device complexity
Solution Approach 1:
The patent changes the frequency parameter of the light source periodically to generate heterodyne interference. By modulating a single light source's frequency rather than using two separate laser lights, the system achieves the required phase detection resolution of 1/500 wavelength while significantly reducing device complexity through parameter modulation instead of dual-source configuration
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 high-resolution, real-time measurement of three-dimensional information and refractive index distributions in live cells and micro-objects, improving upon conventional microscopes by maintaining spatial frequency accuracy and reducing costs.
Implementation Method 1
a photo detector receiving the irradiation light modulated by being passed through the object under measurement in accordance with the scanning, and performing photoelectric conversion on the irradiation light
Implementation Method 2
an optical heterodyne method using lights will be described, but, a heterodyne method is also performed with the similar idea for other electromagnetic waves. This optical heterodyne method makes two laser lights with different frequencies interfere with each other to create a beat signal of the frequency difference, and detects a phase change of this beat signal with a resolution of about 1/500 of a wavelength
Data Source
AI summary
An optical distance measuring apparatus includes: a scanning element scanning a coherent irradiation light from a light source and sending it to an object under measurement; a photo detector receiving the irradiation light modulated by being passed through the object under measurement in accordance with the scanning, and performing photoelectric conversion on the irradiation light; and a measuring unit obtaining phase information of the object under measurement based on a signal photoelectrically converted by the photo detector and a signal to be a reference for the scanning by the scanning element, and obtaining a measurement value regarding the object under measurement based on the phase information.