Wednesday, May 18, 2022

Scientists designed lens-free fluorescent microscope

FlatScope may be the world’s tiniest, lightest microscope for biological applications and beyond.

According to Rice University engineers with a notion that lenses are no longer necessary for some microscopes since they are developing FlatScope, a thin fluorescent microscope whose abilities promise to surpass those of old-school devices.


FlatScope eliminates the tradeoff that hinders traditional microscopes in which arrays of lenses can either collect less light from a large field of view or more light from a smaller field.


Baraniuk said, “We think of this as amping up FlatCam so it can solve even bigger problems


But like all traditional microscopes, telescopes, and cameras, their resolution depends on the size of their lenses, which can be large and heavy and limit their use in biological applications.

This team comes up with a different approach. It uses the same charge-coupled device(CCD) chips discovered in all electronic cameras to capture incoming light, but the comparisons halt there. Like the FlatCam project that inspired it, FlatScope’s field of view equals the size of the CCD sensor, which can be as large or as small as required. It’s flat because it replaces the array of lenses in a traditional microscope with a custom amplitude mask.

This mask, which resembles a barcode, sits directly in front of the CCD. The light that comes through the mask and hits the sensor becomes data that a computer program interprets to produce images.



He said, “A camera in your mobile phone or DSLR typically gets on the order of 100-micron resolution.”


“I think of a microscope as something that allows you to imagine things on the micron scale.”



He said, “It wasn’t as trivial as simply applying the FlatCam algorithm to the same techniques we used to image things that are far away.”

The mask is akin to the aperture in a lensed camera that focuses light onto the sensor, but it’s only a few hundred micrometers from the sensor and allows only a fraction of the available light to get through, limiting the amount of data to simplify processing.

Robinson said, “In the case of a megapixel camera, that computational problem requires a matrix of a million times a million elements.”



Veeraraghavan said the burgeoning internet of things may provide many applications for flat cameras and microscopes. That, in turn, would drive down costs.

He added, “One of the big advantages of this technology compared with traditional cameras is that because we don’t need lenses, we don’t need post-fabrication assembly.”

“We can imagine this rolling off a fabrication line.”


Veeraraghavan said, “To be able to carry a microscope in your pocket is a neat technology.”

The researchers noted that while their current work is focused on fluorescent applications, FlatScope could also be used for bright-field, dark-field, and reflected-light microscopy. They suggested an array of FlatScopes on a flexible background could be used to match the contours of a target.



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