Lensless Sample Observation Using Micrometric LED Matrix Illumination
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Solution Overview
Problem
Existing lensless imaging devices using spatial filters for biological samples face issues with precise centering requirements, reduced light intensity, and non-uniform illumination due to the use of spatial filters, which compromise sensitivity and image quality, especially when observing moving particles.
Innovation Solution
Employing a light source comprising micrometric light-emitting diodes arranged in a matrix, spaced less than 50 µm apart, without a spatial filter, allowing independent or simultaneous activation, and utilizing holographic reconstruction algorithms to process images formed by interference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spatial filter with a small aperture is used to obtain good spatial coherence, then spatial coherence is improved, but the solid angle of emission is reduced, limiting the quantity of light reaching the detector
Solution Approach 1:
The invention divides a single light source into multiple micrometric light-emitting diodes arranged in a matrix. Each micro-LED acts as an independent point source with small dimensions (less than 50 µm), providing good spatial coherence. By having multiple such sources arranged in a matrix, the system collectively provides sufficient light intensity while maintaining coherence properties, thus resolving the contradiction between spatial coherence and light intensity.
2Measurement precision
If a spatial filter is used to define a small opening, then spatial coherence is improved, but precise centering of the light source relative to the aperture is required, increasing device complexity
Solution Approach 1:
The invention removes the spatial filter component entirely from the system. Instead of using a filter with a small aperture that requires precise centering, the patent employs multiple micrometric light-emitting diodes with dimensions less than 50 µm that inherently provide the necessary spatial coherence without requiring any filtering or precise alignment mechanisms.
3Measurement precision
If a spatial filter with a small aperture is used, then spatial coherence is improved, but the quantity of light reaching the detector is reduced, compromising sensitivity
Solution Approach 1:
The invention combines multiple micrometric light-emitting diodes in a matrix arrangement. Each individual micro-LED provides good spatial coherence due to its small size, while the collective output of multiple such sources provides sufficient light intensity. This merging approach simultaneously achieves spatial coherence and maintains sensitivity by ensuring adequate light reaches the detector.
4Device complexity
If micrometric light-emitting diodes are used without a spatial filter, then device complexity is reduced, but uniform illumination must be maintained across the sample
Solution Approach 1:
The invention uses a matrix of micrometric light-emitting diodes where each micro-LED has specific local properties (small dimensions less than 50 µm) that provide good spatial coherence. The collective arrangement of these micro-sources creates a illumination pattern that is both coherent and sufficiently uniform across the sample area, eliminating the need for spatial filters while maintaining illumination quality.
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
Achieves improved illumination, uniform light intensity, and enhanced image resolution, reducing device complexity and cost while maintaining sensitivity and enabling compact designs suitable for biological samples.
Implementation Method 1
The light source comprises at least one micrometric light-emitting diode whose largest diameter or largest diagonal is less than 500 µm
Implementation Method 2
This image is formed by interference patterns between the light wave emitted by the source and transmitted by the sample, and diffraction waves, resulting from the diffraction by the sample of the light wave emitted by the source
Implementation Method 3
This image is formed by interference patterns between the light wave emitted by the source and transmitted by the sample, and diffraction waves
Data Source
Figure 1A~1C
Figure 2~3
Figure 4A~4B
AI summary
The invention is a sample observation device comprising: a light source capable of emitting an incident wave propagating towards a support suitable for receiving the sample; and an image sensor capable of detecting a light wave transmitted by the sample when the latter is placed between the light source and the image sensor. It is characterized in that the light source comprises a micrometric LED, the light-emitting surface of which has a diameter or longer diagonal of less than 50 µm. The invention also includes a method for observing a sample using such a device.