Microscope ring light with a number of different features

microscope-ring-light

Microscopes magnify light. It makes sense that having more light reflecting off of the subject will result in a better magnified image. And so we come to Aziz! Light! It’s [Steve's] LED light ring for a stereo microscope. It’s also a shout out to one of our favorite Sci-Fi movies.

He’s not messing around with this microscope. We’ve already seen his custom stand and camera add-on. This is no exception. The device uses a fab-house PCB which he designed. It boasts a dual-ring of white LEDs. But the controls don’t simply stop with on and off. He’s included two rotary encoders, three momentary push switches, and three LEDs as a user interface. This is all shown off in his demo video after the break.

An ATtiny1634 is responsible for controlling the device. When turned on it gently ramps the light up to medium brightness. This can be adjusted with one of the rotary encoders. If there are shadows or other issues one of the push buttons can be used to change the mode, allowing a rotary encoder to select different lighting patterns to remedy the situation. There are even different setting for driving the inner and outer rings of LEDs.

We haven’t worked with any high-end optical microscopy. Are these features something that is available on commercial hardware, or is [Steve] forging new ground here?

40 thoughts on “Microscope ring light with a number of different features

  1. I’ll be the first to say that I’m not forging new ground in terms of different light patterns and such. I have a commercial unit on my microscope at work which offers some of the same features, but with an awful user interface. My goal was to put the effort into making a much more intuitive user experience, and to add some “spit and polish” with stuff like smooth fades, etc.

    As far as I know, using two different types of LEDs is unique, though I didn’t do an exhaustive search.

    1. It is a really neat build. Though I have the feeling that from all the patterns you have programmed, just a few are actually useful. Half/Quarter-moon illumination is optimal for reading part numbers, while full-ring is great to illuminate components without casting shadows. The use of a diffuse light is probably best when the components have a reflective surface.
      Do you agree?

      1. There are probably some patterns in there that aren’t as useful as others. However, reading part numbers off of chips is just one application and it may demand a particular type of lighting.

        Also, because of the low quality camera I used for the demo, many patterns looked much worse than they do with the naked eye.

    2. Well done! Great video, I especially appreciated the demonstration for reading part numbers. For my home setup I can choose between white or red LED illumination. I find that the red increases my perception of contrast which is helpful for inspecting for solder bridges. Something I’d like to see is the capacity to illuminate with two different colors from opposing sides increase the perception of depth.

      - Robot

  2. Aziz…. LIGHT! Definitely in the top five of my favorite Sci-Fi movies, and an awesome project to have that name for.

    1. I thought about using RGB LEDs, but for electronics work it probably wouldn’t be a real benefit. It might be helpful for other types of microscopy, though.

      1. I’ve been thinking about making LED lights at different frequency bands for specific fluorescence experiments or dealing with diffraction limits on my microscope… but RGB LEDs wouldn’t necessarily have the most useful frequencies.

      2. In my low to mid range microbiology lab in a winery we use color filters to help with visualization. I could imagine that differnt color LED woudl be a help in the lab. I don’t have the time now, but in the future I may try some experiments.

      3. It might have helped with some labeling on chips possibly, if it’s in a specific color, and perhaps using a separate lightsource to see if it makes any difference might be an interesting experiment ‘after the fact’ so to speak, although I also don’t think it matters much.

        And then there’s the angle of the light, and I wonder if you could make a version with some sort of adjustment for that, perhaps some sort of ring with a prism/lens redirection that can be adjusted into the lightpath? Or an addition that sits more on the outside that slants light in more.
        But it’s all a bunch wild ideas really.
        And while I’m throwing things out;: a polarizing filter might be an interesting addition too.

  3. Is it sad that I could tell that he was looking at an AVR Dragon programmer from the very first test shot? (and now that I pay attention to the first image, I see it there too…)

        1. First off, that is one of my favorite jokes that my Dad told me as a child. Thanks for the jog down memory lane, it brought a smile to my face. I miss that guy. :(

          Second @Steve, great build! For the last few weeks I had been planning something like this – a light ring with rotatable patterns and dimming. What never occurred to me was to use of two different types of leds. Good job, I have seen a few of your projects and have been impressed every time.

  4. I use a 9,000$ microscope and it doesn’t have features like that. What it does have is awesome optical clarity, and the ring light is blindingly bright on the LED version. The older ones we have just use a 150w halogen and some fiber optics.

    1. I have a Zeiss OPMI and it has a U shaped ring light source that has small lenses that all focus on a single point.

      The UV is filtered out at the source. The IR cut filter eliminates virtually all UV as well. The reason for the fiber is to get a hot source away from the scope and lessen bulk.

  5. Problem is, that many of these new high power LED’s are from China and they are CRAP, the organic dyes are wrong.
    So what you get is high power LED’s with too much UV or IR, but you cannot see it, then you shove it through a lens assembly and into your eyes!!!!!!

    Personally I would NEVER use an LED ring light on my optical microscopes

    1. Seems like he has more then enough lumens, so put a diffuser (like they use on LED backlight flat panels) between the source and the subject and problem solved.

    2. The white LEDs work by emitting tight-band blue light, which is then absorbed and re-emitted as wide-band yellow light by some phosphors. Getting UV or IR light out of the process would require some technical heroics. …so, yes, I agree some references would be nice.

      1. He’ll probably have a friend draw a picture in paint stating his claims in a table and will link to that as ‘proof’, that’s how things are done on the internet presently :/

      2. It’s possible he’s mixing these up with frequency-doubled green lasers, where the cheap ones do in fact have shoddy filters that let gobs of un-doubled IR through.

    3. Simply knowing that white LEDs use inorganic phosphors, not “organic dyes”, is pretty much all you need to realize that this is bogus. Even if he’d gotten it mixed up with frequency-doubled lasers, there’s still no organic materials involved.

      I hear there are some fancier white LEDs which use near-UV emitters (instead of royal blue) with a mix of phosphors to produce a more natural spectrum. These could possibly leak some UV, but these are specialty LEDs, not typical cheap Chinese products.

      And even if any white LED *somehow* produced so much IR by proportion that it could cause thermal damage to the eye, you’d instantly throw it out as defective, because it would be so visibly dim.

        1. True. For example, one might think ammonia (NH4) is organic because it exists in living things. Yet according the chemical definition, it’s not organic, because it contains no carbon.

          And Rhodamine 6G (C28H31N2O3Cl), which is used in dye lasers, is considered organic because it does contain carbon; despite not being something you’d normally find in a living thing.

          However, the phosphors used in most LEDs (like cerium-doped yttrium aluminium garnet, for example) fall under no definition or organic; neither colloquial or chemical.

    4. The only danger with regular white LEDs is excessive blue light (not UV), and this pretty much only applies when staring into the LED itself.

      There was actually a new class of radiation warnings instituted for white LEDs, “blue light hazard” or something like that :P

      1. Probably related to the fact that some of the blue range of the spectrum does actually interfere with your biological clock (some bodies interpret it as being “morning” and reset the biological clock, leading to insomnia).

        http://www.eurekalert.org/pub_releases/2001-08/tju-jnu080901.php

        http://www.nytimes.com/2011/07/05/health/05light.html?pagewanted=all&_r=0

        People like me can easily lose sleep after being bombarded with “blue” light during night time, those fluorescent lamps advertised as “daylight” color are the worst!

      2. 400 – 500 nm light has been shown in rodents to cause retinal damage by retriggering photoreceptor bleaching before the visual cycle completes.

        Not shown in humans yet, but that hasn’t stopped people from slapping warning stickers around and making blue-blocking sunglasses.

  6. Steve, I just got LED lights on one scope at work. I would’ve easily spent more for a kit like this and assembled it myself (or a partially assembled kit). I’m happy with mine, (It has quadrants too, but NOT AT ALL like the AZIZ), but your versatility is awesome!

    P.S. I have 2 of those B&L’s at work and I totally love them for their price point.

  7. I wonder if the next step for this is some sort of automated polynomial texture mapping to generate high detail computer generated surface maps.

  8. In the video, around the two-minute mark (when the various lighting modes are being discussed) I noticed that regardless of what pattern is being displayed, they all suffer from a basic dark shadow in the center. Is that intentional? Am I missing something? In fact, it appears that a lot of the light is being wasted illuminating areas of the object that will never been seen by the microscope. Perhaps the LEDs should have been mounted differently, then angled inward to get maximum illumination on the field of view.

    1. You’re probably not imagining it. The LEDs are mounted off of the PC board on purpose, to allow their leads to be bent to aim the LEDs. I have only done a very rough job at tweaking their aim at this point.

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