Microscope Stage Illumination

Hello-

I'm wondering if anyone can provide some more ideas for direct illumination of the stage of a microscope with an LED. I found this great resource here:
http://eldredspellflutes.com/LED_index.htm
But in his case he used a ready made conversion kit and had optics underneath to support the size.

My stage has at most 3.5" of clearance to the bottom of the iris- I think I could mount a star or a round on top of a lag bolt (heatsink) and mount it- the power would be external to that.

Anyone have any other links for non-housed lights that are very thin? My 3 watt Riverrock flashlight was more than sufficient to illuminate the stage.


Thanks in advance-

Jason

First thing first: Welcome to CPF!

If you are looking for a quick solution, a power LED, a chunk of aluminium and three Nimh cells would do the trick, just put all three cells in series and power the LED, and mount the led on the aluminium to have a good heatsink.

If you want to go the efficient way browse the forum for drivers/converters there are plenty to choose from.

I think your biggest problem will be how to find a good color rendition, since white leds lack the red component needed to achieve a high CRI

Tell us what tools you have available and your goals and we can go from there.

Have Fun!


Pablo

Do you need a very intense spot? For higher magnification, I figured that the specimen would look too dim. You can use some of PolymerOptics' fiber optic concentrator optics. You can get a super-intense 6mm diameter round spot with this thing. The height of this optic from the base of the LED emitter is 15.6mm, and the distance from the top of the optic to the focal point (that 6mm spot) is 14.5mm. So ~30.1mm, or about 1.85". This will give you plenty of room for a heatsink to cool the LED. Now, you can defocus this optic, I am sure, and increase the size of the spot while decreasing the brightness some. Here is the link to the PDF:

http://www.polymer-optics.co.uk/141%20-%20Single%20Cell%20Concentrator(Luxeon).pdf

You can get these at Future Electronics for $2 to $3. Its part number is "141". Fraen has something similar, but I believe that the part is much more expensive.

While at Future Electronics, you can pick up any old Luxeon K2 LED and it should be bright enough, cheap enough, and durable enough for your application (it can take the heat well). These are anywhere from $2.80 to $5.10, and they come in cool white, neutral white, and warm white. They also come in different brightnesses (binned by letter). The neutral white may work well if you wan to render colors good, or go with the warm white.

The above mentioned optic comes with an optic holder, and you have a choice of three different lens holders (for different LEDs). The 151 optic holder works with the K2 emitter, the 128 lens holder works with the 3W star, and finally, the 121 works with any 1W star or any bare emitter. These are used to just hold the optic at the right height, and they fit around the different LED emitters' different shapes.

You do not have to drive the LED too hard if you use that optic, maybe. It says in the datasheet for that concentrator that it produces more than 850,000lux at the concentrated spot. That is with any old 25 lumen 1W LED. With a K2, you can power it at low levels and still get an intense spot.

As for a cheap driver (if you want to go really cheap), any standard LM317 voltage regulator would work with a standard 6V battery pack or wall wart. It is very easy to wire, and you can hook it up to a dimmer if you want, also. All that is left is finding a piece of aluminum or copper around to mount this to. Any old Pentium I processor heatsink should keep it cool, as long as you do not drive the LED too hard. Screw the star-shaped board in place (use thermal paste if you want), and solder it up to your circuit and you will be good to go!

So, does the light mount directly under the tray that holds the specimen (lights from beneath), or is it off to the side and uses mirrors? Just wondering. It was hard to picture exactly what you wanted. Either way, it should be simple to mount.

What do you think? I hope I understand what you need. I hope that I made sense, too. If you do not like that particular optic, you can find many different kinds at Future Electronics for a good price. All of what I said is just a cheap, solid, and simple way of lighting a small area, like the specimen glass. The reason I mentioned Future Electronics is that they are the main reseller of Lumileds LEDs. It is where you can get them direct and save a few bucks. They have lm317 parts plus any resistors, too. If I am going the wrong direction, please tell me. Well, you came to a nice place. We will help you through whatever you need.

-Tony

Wow. Talk about the motherload...




Might be too large. Hrmmm.

The stage itself has a concentrator optic. Earlier I took my 3 watt River Rock and shined the light up the center of the hole in the base. That was MORE than enough to illuminate all levels of magnification, so I have no doubt that a 1 watt will suffice.

I was trying to avoid a direct drive system by using a board and will thus take a look at those links. The concentrator optic that fits over the lumiled will be a nice addition- I don't need to worry about alot of spill and the more light the better.

I'm intending on using this to describe and count yeast colonies for my beer and wine making- we're going to be making our own house brews soon if this works by selectively cloning different strains from our beers and replicating them.

Thanks again for the help, and I'm hoping this photo clears things up some!

Jason

Tony graciously has permitted me to post a PM here to update the thread so that should anyone else come along they might get their answer here. Sorry for the delay, been traveling ALOT.
-------------------------

No problem. I think that I was thinking too narrowly with products that would work for you. I do not work with different varieties of microscopes often like you would, so I only pictured in my mind just a few that I have seen and used before for classes.

I thought that you needed the tightest little spot possible, and I just had that one optic in mind. A reflector would work nearly as well. If you would shine a flashlight using an high flux LED and a reflector on a wall at a close distance, there may be a good chance you will get a projected donut shape in the beam. However, I was thinking that if you would de-focus the emitter in the reflector, you can focus it where you can get a tight, solid spot at close distances.

For the most part, those two lamp modules should work for you. If you would happen to get a "donut" beam, you could move the module so it is slightly off center so the dim donut hole is not projected directly beneath your slides. It seems like it would be easy to pop off the springs (if needed) and solder on your own wires directly onto the contacts on the back of the driver board.

So I just wanted to check. Are these modules to be free standing (fixed) with the battery pack and/or converter sitting beside it secured, or do you want to fit this module in a flashlight to rest underneath the microscope?

What would the reason be that you would use batteries for this light? Is it so it can be removable to be used for other things? Lithium batteries can chargers seem expensive, especially if you do not plan on making your microscope mobile. In that case, it may save you the trouble to use a cheap wall adapter. Now, if you have any intentions to move the microscope for on-the-scene field work, then the battery idea would be awesome. Imagine firing that puppy up next to someone else's microscope when they have the cheesy battery-powered screw in light bulb to illuminate things. That would catch some attention for sure. I did not save the picture that you posted of your microscope, and I just forgot how things are set up and how much room you have.

I wanted to point out that if you get either module, it will have its own converter installed in the rear under the springs. I think they are buck circuits to be used with one or two li-ion cells (which would work I guess if you wanted to go the battery route), but you would have to check the descriptions and reviews/comments. This driver may possibly not work for the fixed lighting, depending on the minimum and maximum V-in of the driver board and the supply voltage of your wall adapter. It may work however, seeing that you plan on using a 5V adapter. A cell phone charger may work, but you may not get the 1000mA that you want.

You know, if you want, you can even get just the reflector that is the same or similar as to what is used in those modules. This way, you can specify the emitter (if you have much of a choice) and the driver. If you want to make this use a plug-in wall adapter, you do not have to worry about taking out the included driver to use the AMC7135 1050mA regulated driver instead, simply because you can choose which to buy from the start. Here:

http://www.dealextreme.com/details.dx/sku.3257

Now, according to the reviews, I remember that that above bare reflector does not work with the full size Cree star or circle shaped board (16mm or 19mm), but instead, any board that is under 15mm will fit, such as the following 14mm Cree XR-E P4 circle, for example:

http://www.dealextreme.com/details.dx/sku.3475

You can get the larger star with the newer Q5 emitter and trim it down, but that sounds like a pain. I guess you would only have to trim off the protruding hex-board material to allow it to fit. The best thing about getting the reflector and emitter separate (my main reason for bringing it up) is that you can purposely defocus it by adding a cardboard disk on top of the star to raise up the reflector, or by making the LED sit up higher into the reflector. This way, the spot would be tight and bright and better focused. If you play with a mini-magLED, you can get a super small spot on a close by wall or piece of paper by de-focusing the LED a bit. I forget which way you have to turn the head. The same should work for the Cree and the orange-peel reflector. In addition, it is cheaper to build your own (and not necessarily any more difficult since you have to solder things anyways). The aluminum relfector set costs only $2.77 and the Cree XR-E P4 emitter fixed on the 14mm board costs $6.13. This is $8.90 total so far without the cost of the driver, of course.

I just wanted to share some other ideas. I think that you can go any route by using the reflectors from DX and be very pleased with the super-bright results. I understand time and money has to be an issue some, so you do not want to go through too much hassle just to light the specimen slides with today's LED technology. I suppose the cheap $3 10W xenon bulb and reflector module from DX would work easier, too, but there may be an issue of cooking your specimens (if organic). That would not be good at all! :mecry:

Anyway, keep me posted on what you come up with. It is exciting to see LEDs being used for such application more often. It is sort of refreshing! Good luck!


-Tony

P.S. - Feel free to post this on your thread if you think it would be of help to other people. I never thought of it before.




Quote:
Originally Posted by purduephotog
I'd like to thank you and ask a pair of questions as a followup for my microscope stage illumination.

1) I saw this linked over at FatWallet.com- it would appear to meet most of my requirements:
http://www.dealextreme.com/details.dx/sku.1447
or
http://www.dealextreme.com/details.dx/sku.1343
And then I'd need to power it, so:
http://www.dealextreme.com/details.dx/sku.975
And Charge it
http://www.dealextreme.com/details.dx/sku.1251

2) If that isn't appropriate, there's also the individual parts (I could scrap an AC adapter that produces 5 volts) and purchase a 10 pack of regulators such as this:
http://www.dealextreme.com/details.dx/sku.1885

Thanks again for your help and I can post this on the thread if you'd like-

That's a great Idea.
Maybe one of the 5 mode dropin would be useful instead of the single mode linked. Three brightness modes depending on what you are looking at. I doubt that strobe or sos would be of much use tho.
They need to be cooled tho as they still generate a lot of heat.
3 Watt into a small metal can is bound to get hot.

How about one of those 6V lantern batteries as a power source or maybe a SLA.