New to me Zeiss Standard

[75RR]

You could get a completely new holder made that you can stick though the open hole.

Does one need (forward/backward) movement in order to focus with a led light?
Does Köhler illumination exist with led lighting?

Links to making ones own led light source?
I confess not being very good with electricity. Happier with plug and play.

[Ichthyophthirius]

Does one need (forward/backward) movement in order to focus with a led light?

Yes. That's provided by screw 1 (M5; 4-stared grip)

There are a lot of LED replacement ideas and LED power supplies on the internet. It's a project rather than a quick fix.

All the replacement requires in terms of Koehler illumination is placing the LED in exactly the same position as the original lamp filament, and having a single-chip LED with a sufficiently large chip. Maybe someone in the forum with experience can make a recommendation?

As for the aluminium rod, here is one suggestion (no guarantees):

Take an aluminium rod, 20 mm diameter, 120 mm long.

Get a workshop to cut an M19 thread around the outside of the bottom 50 mm of the 120 mm rod. The bottom of the rod will now fit through the hole in the lamp socket (20 mm diameter).

Use two M19 counter nuts (either side of the lamp socket) to fix the rod in the illuminator. The thread is 50 mm long, so you'll have room to find the right position.

Get a single-chip LED on a star platine, solder on wires, and glue the LED to the flat top of the aluminium rod using thermal conduction glue.

Connect the wires to a suitable power source.

Scetch (not drawn to scale)

[75RR]

Sorry about the repeated posts, can't seem to delete them.

Get a single-chip LED on a star platine

Can you be more specific? Led #, type, source, watts, where might I get one?

Know someone who can do this, that is make metal parts, but not the electrical connections.

Would still need transformer and dimmer, wouldn't I?
.

[Ichthyophthirius]

Can you be more specific? Led #, type, source, watts, where might I get one?

I don't have enough knowledge either to make a recommendation. The LED market changes so quickly ... if no-one answers in this discussion, just open a new discussion to ask for recommended LED and suitable LED dimmer design.

I wrote star platine, because you can also buy the LED itself, but that's incredibly difficult to solder with a large soldering iron so you buy them pre-attached to a star or round base with contacts. The bases are about 20 mm in diameter.

I have previously used the white Cree XM-L U2 on a copper base (available on Ebay etc.), a very bright power LED when run at 2 W. However, even with a chip area of 4 square mm the chip is smaller than the Original light bulb filament of the Zeiss illuminator.

There are LEDs with larger areas http://www.candlepowerforums.com/vb/sho ... T-90/page2 , like the Luminus SST-90 (9 square mm) http://mevial.ru/wp-content/uploads/201 ... igned1.jpg but I haven't tested it and never heard of anybody using it on a microscope - that's why I think you should ask somebody who's more knowledgeable in this area.

Ichthy

[rjlittlefield]

Sorry about the repeated posts, can't seem to delete them.

I've deleted the posts you edited to say doubled.

The forum software does allow you to delete your own post, but only if it's the last one in the thread. If you try to delete an earlier doubled post, or if somebody has replied after you posted, then only an admin can fix the problem.

Doubled messages usually happen because the forum is slow at responding and the user hits Submit again. The defense against this is to push the Submit button only once per attempt. If it looks like the Submit didn't work, then hit Preview instead. Wait for a response, or keep hitting Preview until you get a response, then look at the "Topic review" section below the editing box to see if perhaps your earlier Submit attempt really did get through despite appearances. If you do not see your message, and only then, hit Submit again. Repeat as necessary.

Hope this helps!

--Rik

[Pau]

There are LEDs with larger areas http://www.candlepowerforums.com/vb/sho ... T-90/page2 , like the Luminus SST-90 (9 square mm) http://mevial.ru/wp-content/uploads/201 ... igned1.jpg but I haven't tested it and never heard of anybody using it on a microscope - that's why I think you should ask somebody who's more knowledgeable in this area

All the pictured LEDS are arrays like mine, no actual single LEDS

[Ichthyophthirius]

All the pictured LEDS are arrays like mine, no actual single LEDS

Are you sure? XR-E, XM-L, SST-50 and SST-90 are usually considered "single chip" as opposed to the two LEDs on the right of the picture; there might be thin wires running across the surface of the chip, but there are no wide areas of non-emitting surface (no dark areas to speak of). In a perfectly aligned Koehler setup the dark areas are not important anyway. They might be arrays on a deep level (are they?), but they are certainly "single chip" for practical purposes.

What Glen "doesn't want" are arrays like this: http://media.digikey.com/Photos/Cree%20 ... 000M01.JPG

Regards, Ichthy

[Pau]

Ichthy,
I'm not aware of the usual nomenclature but the pictured LEDs -and mine- are micro arrays of tiny leds covered with a common phosphor, why if not so high number of connectors?. In fact I think (but not sure at all) that all high power LEDs follow this design. Just in my case the 3x3 matrix is more clearly visible because the LEDs themself are less closely packed so for microscope illuminators it seems a priori less desirable.
Please correct me if I'm wrong.

EDIT: I was WRONG. Now I have some Cree XP and XM-L and they are single chip LEDs with uniformly illuminating surface except the extreme phosphor borders

[enricosavazzi]

All the Cree XM-L I own or have seen are single-die (= single chip). At least some of them have multiple die contacts, probably to spread the current through multiple wires connecting the die and package.

I have myself thought of modifying a Zeiss illuminator in much the same way as proposed higher up this thread (i.e. by mounting the LED on a round aluminium rod), but have not yet gotten around to doing it.

Among the variants of this idea I have thought are:
- Using a copper rod instead of aluminium (slightly higher heat conduction and heat capacity).
- Attaching a heatsink at the external end of the rod, to increase heat dissipation.
- Using a short rod completely contained within the illuminator, drilling a cylindrical hole at its back and mounting the end of a a heat pipe in the hole, to transport the heat to an external heatsink more efficiently than just by heat conduction.
- Cutting the casing of the illuminator approximately to half length, so that I can instead use a LED directly mounted on a heatsink. The LED can be centered and focused by mounting the heatsink on a system of aluminium profiles that allow a few mm of travel and tilt in three directions, and individually locked with thumbscrews.

Another thing I thought of doing is mounting a parabolic reflector around the LED (same type used in most LED torches). I don't know, however, whether the microscope condenser can use this extra, slightly off-axis light. Likely not, if it is off-axis by more than a few mm.

[Ichthyophthirius]

I have myself thought of modifying a Zeiss illuminator in much the same way as proposed higher up this thread (i.e. by mounting the LED on a round aluminium rod), but have not yet gotten around to doing it.

Among the variants of this idea I have thought are:
- Using a copper rod instead of aluminium (slightly higher heat conduction and heat capacity).
- Attaching a heatsink at the external end of the rod, to increase heat dissipation.
- Using a short rod completely contained within the illuminator, drilling a cylindrical hole at its back and mounting the end of a a heat pipe in the hole, to transport the heat to an external heatsink more efficiently than just by heat conduction.

Hi Enrico,

I'm using an LED mounted to a simple turned aluminium rod like this: http://www.mikroskopie-forum.de/index.p ... #msg128161 that fits into the short illuminator tube in the foot of the Standard.

From my experience, and others using it, the size of the aluminium rod is sufficient to dissipate the heat (< 2W). Not to say it's vastly oversized as it is. We found that cooling rips are not necessary (looking very cool, though). In addition, the aluminium rod has a large contact area with the illuminator tube and the lamp housing, so the heat is quickly conducted away into the microscope stand. This is much more efficient then heat convection through cooling rips.

The critical point is the junction between the LED star base and the aluminium rod. This is were the heat conductivity is the lowest - so it's important to use heat conducting glue or paste and keep the layer of glue/paste very thin. Compared to the glue junction, the difference between aluminium and copper doesn't matter much.

To improve the contact between star base and aluminium rod, I also have a piece with two little threads (M2) for small screws cut in http://www.mikroskopie-forum.de/index.p ... 7#msg87457 , that allow to star base to be attached very tightly. This also allows to exchange LEDs quickly (when using heat conducting paste).

Ichthy

[enricosavazzi]

Hi Ichthy,

my main reason for considering a heatpipe or cooling fins is that I am planning to use a 10W Cree XM-L. The specifications say that its life span will be shortened if it is fed continuously at more than 5W, so it seems that heat is an issue at these power levels.

I don't know yet whether operation at high power will be really necessary, but DIC eats a lot of light. It might also be useful to temporarily feed the LED at high power (in "flash mode") to shorten exposure times.

One idea I had was to attach three or four LEDs of different wavelengths (UV, purple, royal blue, blue) side by side for fluorescence, in addition to white, to the same heatsink. A sideways slider would be used to switch the desired LED into position, but re-centering would also be necessary. Since only one LED would be powered, the heatsink does not need to be very big.

[75RR]

Have removed the base to have a look inside. Had to buy some allen keys.

Do not appear to have a Field Diaphragm. Not broken, just not there.
Also tube has no lens. It is just a hollow tube.
First photo is set at 20 See red circle. Second one is set at 0.
There is no regular "leaf diaphragm" (as I have seen in some photos) yet turning the dial between 0 and 20 does seem to have a distorting effect.

Is this an alternative Field Diaphragm? Does not look broken nor does it seem to be missing anything.
Do not know what to make of this. Any suggestions?

[Ichthyophthirius]

Do not appear to have a Field Diaphragm.

The unit is called the "Diaphragm insert" "46 70 58". It's possible that somebody has removed the blades of the iris or, more likely, that the iris is stuck and the leaver is broken out.

Hold the unit horizontally and carefully remove the three large metal screws. This should allow you to remove the black cover and then the metal ring.

Have a look if the iris is still in there. Be very careful when you open the unit so the iris blades don't fall out (it's a lot of work putting it back together).

Here are a few pictures of how to clean the iris if necessary: http://www.mikroskopie-forum.de/index.php?topic=9565.0

Never oil/lumbricate the blades of an iris (for example to get it going again). They have to be absolutely grease-free.

Also tube has no lens. It is just a hollow tube.

It is likely that the illuminator connecting tube for the small Standard stand has no lenses in it. Compare this (no lens): http://www.ebay.com/itm/251688403793 to this (much longer; with lens) http://www.ebay.com/itm/311118687197

Ichthy

[75RR]

Many thanks for all your help Ichthy.

The unit is called the "Diaphragm insert" "46 70 58". It's possible that somebody has removed the blades of the iris or, more likely, that the iris is stuck and the leaver is broken out.

Looks like they have been removed, though I can not think why.
I suppose that means a new one. Should I attempt to get a tube with a lens as well?

glen

[Ichthyophthirius]

Looks like they have been removed, though I can not think why.
I suppose that means a new one.

UN-believable. Somebody has canibalised the iris ... Getting a "new one" sounds easy, but there were two common versions (there were in fact even more), 46 70 57 (for Phomi III and Universal) and 46 70 58 (that's the one you want; for Standard) which differ in their collector lenses (again the reason is the difference in the size of the bases of the different models) but the number is rarely written on the Diaphragm insert unit. So you either have to ask the seller where the Diaphragm insert came from, or feel lucky, or transplant the iris into your old insert.

Your Diaphragm insert is the older version, with 13 blades, as opposed to the newer version with 6 blades.

Should I attempt to get a tube with a lens as well?

My guess is, that the illuminator tube that you have is the correct one [ would be very helpful if somebody could confirm that ].

A tube other than the correct one might not work and the long one with the lens might not even fit into the base of the microscope. I'd wait with the purchase until you have reliable information.