DIY Scope

For MIT 6.123/20.345 (Bioinstrumentation) I’m building a bright field/fluorescence microscope from scratch; it’s surprisingly cheap (for a serious microscope) so I thought I’d share what I’ve got done.

Conceptually, a bright field microscope needs surprisingly few specialized parts (a bright field microscope is what most people think of when they think of a microscope — you see an object backlit by the microscope light). Most of the magic happens in the objective — and those are readily available from the optics supplies like Thorlabs or Edmund Optics. Besides the objective, you’ll need a couple of convex planar lenses (not too difficult to come by) to focus the beam, and a mirror to help with alignment.

A simplified schematic of the optical path is below:

DIY Bright Field Microscope Schematic

A red LED is used to provide the brightfield light; technically a blue LED would be better (because blue is a smaller wavelength and therefore provides a higher resolution), but would make things a bit messy when I integrate fluorescence later on. The LED light hits the sample and scatters from it; the objective collects the light and needs a 200 mm lens (f1) to correctly collimate the light. The collimated light gets directed to the middle of the camera’s field of view with the mirror, and voila, you have a microscope!

Here’s an image of my constructed microscope (made from mostly Thorlabs’ parts):

DIY Microscope

I tested it using a standard with line thicknesses of known size:

Picture of the standard

and could detect the smallest lines (~18 lines/mm) with pretty good resolution:

Image of the standard through my microscope

I also used a target with 600 lines per mm (meaning the lines should be around 1.6 um apart), and was able to resolve the lines. So we’ve got a resolution of around a single micron on this microscope — enough to make microspheres and most cells visible as blobs.

A 600 line per mm standard, as seen from the brightfield microscope

Right now I’m working on adding a green laser to the optical path for fluorescence microscopy, and figuring out a way to reduce the cost of the microscope. It looks like the final fluorescence microscope will cost in the $1000-$2000 range (in large part because of the camera); I’d like to drop that cost down by about $1000 ideally to the $500-$1000 range. If anyone knows of a good place to get cheap (but not crappy) optics, computer vision cameras, etc., let me know!

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~ by asymptoticdesign on 10 March, 2012.

5 Responses to “DIY Scope”

  1. This is awesome !

    I’d love some higher res images ( more of them too! )

    Where did you source the parts from? Do you have that parts-listed out?

  2. All of the parts are from Thorlabs (mostly because that’s what the lab had lying around). I’m currently making a parts list for the brightfield path, the fluorescence path, and a confocal module that I’m working on adding to it.

    I’m shooting to have a final parts list and schematics (along with code for software) ready by June. After that I plan to find ways to reduce cost, probably by finding suitable replacements at surplus suppliers, etc.

  3. could you post the final parts list and schematics list ? Thank you.

  4. Hello Nathan,

    Did you get any further with this? I’m teaching a class in materials at CalArts and my students want to make microscopes. They don’t need to be perfect, but the images should be suggestive.

  5. I really love to read out your blog, i guess you have made huge researches about led bulbs and led lights. keep it up.

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