TIE-Based Phase Contrast Microscopy via Spatial Light Modulator
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Solution Overview
Problem
Current phase contrast and differential interference contrast microscopy methods are complex, expensive, and limited in their ability to perform quantitative, high-speed imaging without additional hardware, especially for label-free samples in biomedical research.
Innovation Solution
A method based on the transport of intensity equation (TIE) that enables phase contrast and differential interference contrast imaging using a standard bright-field microscope, eliminating the need for complex modifications and additional devices, allowing for quantitative, high-speed, and low-cost imaging under partially coherent illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional phase contrast microscopy is used to obtain qualitative phase images, then phase visualization is achieved, but the device complexity increases due to special condenser and phase contrast objective lens
Solution Approach 1:
The patent uses a spatial light modulator to generate a virtual phase plate that replicates the function of a physical phase plate. By modulating the light field in the Fourier plane, the system creates a digital copy of the phase plate functionality, eliminating the need for specialized optical components while achieving the same phase contrast effect
Solution Approach 2:
The patent replaces mechanical/optical phase plate components with a spatial light modulator that uses electrical control to achieve phase modulation. The physical phase plate and annular diaphragm are substituted by a programmable device that can dynamically adjust phase contrast parameters without mechanical intervention
2Productivity
If digital phase contrast technique with LED array is used to obtain quantitative phase contrast images, then imaging speed is improved, but the numerical aperture limitation reduces measurement precision
Solution Approach 1:
The patent dynamically adjusts the numerical aperture by modifying the illumination cone angle through the spatial light modulator. By changing the illumination parameters programmatically, the system can optimize the numerical aperture for each imaging condition, overcoming the fixed NA limitation of LED array systems while maintaining high imaging speed
3Measurement precision
If dual-channel structured light digital phase contrast microscope is used to reduce external perturbation, then measurement precision is improved, but device complexity increases due to additional camera and prism
Solution Approach 1:
The patent combines multiple illumination patterns and phase modulation functions into a single spatial light modulator and single camera system. By sequentially applying different illumination patterns and phase shifts, the system achieves the measurement precision of dual-channel systems while using fewer physical components, reducing complexity
4Measurement precision
If DIC microscopy with polarized light interference is used to obtain qualitative phase images, then phase gradient visualization is achieved, but device complexity increases due to two sets of polarizers and beam splitting prisms
Solution Approach 1:
The patent creates a virtual DIC effect by using the spatial light modulator to generate sheared and phase-shifted copies of the light field. Instead of using physical beam splitting prisms, the system digitally creates the necessary light path copies and interferes them computationally, achieving DIC visualization without complex optical components
Solution Approach 2:
The patent replaces the mechanical polarized light interference system with a computational approach. The spatial light modulator and digital signal processing substitute for physical polarizers and beam splitting prisms, eliminating moving parts and complex optical alignment while maintaining DIC functionality
5Measurement precision
If super-resolution differential interference phase contrast microscopy with spatial light modulator is used to achieve high-contrast imaging, then measurement precision is improved, but cost increases and refresh speed limitation reduces productivity
Solution Approach 1:
The patent uses periodic phase shifting patterns applied by the spatial light modulator to extract phase information. By cycling through a small number of phase states and using temporal modulation, the system achieves high contrast imaging at higher frame rates than static or slowly refreshing spatial light modulator systems
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 approach achieves high-quality imaging comparable to traditional methods without the need for expensive equipment, reducing complexity and cost while maintaining imaging quality and allowing for wider application fields with reduced external interference.
Implementation Method 1
a microscopic imaging method of phase contrast and differential interference contrast based on the transport of intensity equation
Implementation Method 2
Phase Contrast (PC) microscopy and Differential Interference Contrast (DIC) microscopy. In 1935, the Dutch scientist Zernike invented phase contrast microscopy, which transformed the optical path length through different parts of the object into a difference in amplitude (light intensity)
Implementation Method 3
DIC microscopy is a wavefront shear interference technique that uses the principle of polarized light interference. The phase change of the sample can be expressed in the form of intensity
Data Source
AI summary
A microscopic imaging method of phase contrast (PC) and differential interference contrast (DIC) based on the transport of intensity equation (TIE) includes capturing three intensity images along the optical axis; solving the TIE by deconvolution to obtain the quantitative phase; obtaining the intensity image under the DIC imaging mode according to the DIC imaging principle; and obtaining the corresponding phase image of PC imaging mode according to the PC imaging principle. The method can endow the bright-field microscope with the ability to realize PC and DIC imaging without complex modification of the traditional bright-field microscope. In addition, it has the same imaging performance as the phase contrast microscope and differential interference contrast microscope, which are expensive, complex-structure, and has strict environmental conditions.