I bought this illuminator for a good price. Originally it came with the socket for an arc bulb but without the bulb or power supply. So I proceeded to modify it to accept G6.35 bulbs. I got the bulb base installed at a height that more or less centers the bulb filament with the illuminator's parabolic mirror.
I installed a 120V 300W bulb on the base and tested it...but I have two potential problems:
1.- I can see the filament reflection (dark) when I project the light into a white surface. Do I need to add a diffussion filter somewhere down the line?
2.- The unit does not get extremely hot on the outside (it is very well designed for heat dissipation) but you can feel an extreme heat coming from the front opening. I am worried that such extreme heat could damage the mirror or its coatings or the condenser on the front (since the bulb gets ~4mm from it when the condenser is retracted to its max)
On the other hand, I imagine that the arc bulb would have produced extreme heat also.
Any comments?
Zeiss illuminator conversion
Moderators: rjlittlefield, ChrisR, Chris S., Pau
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Pau
I have never seen a three hundred watt tungsten bulb used for a microscope and the reason is exactly what you have discovered. They put out too much infra red. There are issues of source size as well.
Normally the reflection from the rear reflector should be close to the same brightness and size as the main image. I have seen alignment instructions that tell you to bring them both into focus and to interleave them. This is usually done by adjusting separately the distance between the arc or filament plane and the mirror and then the distance to the condensing lens.
Whether or not your optics will tolerate the amount of IR you are trying to shoot down them depends on what kind of arc lamp was originally in there.
Arc lamps are much more efficient than tungsten lamps and produce much less IR and more light per electrical watt. So it is quite likely if you run that lamp you will cook downstream optics. The highest wattage tungsten halogen lamp one sees on microscopes are typically 100 watts and even those are much less common than 50 and 20 watters. You should drop back to one of those.
Also there is usually an IR reducing filter close to the bulb. Sometimes this is the first condensing lens other times it may be a little farther downstream but it is recognizable by a bluish tint to the glass.
One of the numerous reasons for using short arc lamps is that they have a small source size. The above mentioned quartz halogen lamps also have a 2 or 3 mm square source size. The optics are probably designed accordingly and using a 300 watt lamp that probably results in lower field intensity depending on the area of the filament you selected.
Edit: Just saw the picture you uploaded. The XBO 75 or HBO 100 that was originally in that lamphouse was exactly centered on the circular mount. Your set up is off by a significant amount. You should be able to
find a 100 or 50 watt lamp that will drop into that socket. That lamphouse was never designed for more than 100 watts.
Also condesers for that lamp house are pretty short focal length and do get pretty close to the arc lamp. One often sees them with cracks in them. These depending on their orientation may or may not reduce the output. They often get cracked when arc lamps pop which they do ocassionally if they are run too long.
Normally the reflection from the rear reflector should be close to the same brightness and size as the main image. I have seen alignment instructions that tell you to bring them both into focus and to interleave them. This is usually done by adjusting separately the distance between the arc or filament plane and the mirror and then the distance to the condensing lens.
Whether or not your optics will tolerate the amount of IR you are trying to shoot down them depends on what kind of arc lamp was originally in there.
Arc lamps are much more efficient than tungsten lamps and produce much less IR and more light per electrical watt. So it is quite likely if you run that lamp you will cook downstream optics. The highest wattage tungsten halogen lamp one sees on microscopes are typically 100 watts and even those are much less common than 50 and 20 watters. You should drop back to one of those.
Also there is usually an IR reducing filter close to the bulb. Sometimes this is the first condensing lens other times it may be a little farther downstream but it is recognizable by a bluish tint to the glass.
One of the numerous reasons for using short arc lamps is that they have a small source size. The above mentioned quartz halogen lamps also have a 2 or 3 mm square source size. The optics are probably designed accordingly and using a 300 watt lamp that probably results in lower field intensity depending on the area of the filament you selected.
Edit: Just saw the picture you uploaded. The XBO 75 or HBO 100 that was originally in that lamphouse was exactly centered on the circular mount. Your set up is off by a significant amount. You should be able to
find a 100 or 50 watt lamp that will drop into that socket. That lamphouse was never designed for more than 100 watts.
Also condesers for that lamp house are pretty short focal length and do get pretty close to the arc lamp. One often sees them with cracks in them. These depending on their orientation may or may not reduce the output. They often get cracked when arc lamps pop which they do ocassionally if they are run too long.
This lamp house is for 100W halogen or 50W HBO, although there are models for 75 or 150W HBO, this will provide enough or even excessive light for most techniques. 300w will be excessive, those lamps normally use cooling fans (projectors...)
Do you have the instructions of the lamp house?, I can provide you a link or pdf
To set Köhler illumination and center the lamp you need no frosted glass, but at the collecting tube inside the Zeiss microscope base there is one that can be switched in or out with a hex key
I see the lamp way out the center, even if you can focus it rightly its mirror image will be likely defocused. There are round smaller lamp holders that could fit better.
The lens for HBO arc lamps is different (more dioptric power) than the one for halogen, although with a LED with a size similar to the square lamp filament I find the HBO lamp collecting lens working better than the halogen model for true Köhler illumination.
To prevent heat damage look for a heat filter, there are two main types: old style transparent very light green glass and metallized reflective "heat mirror"
EDIT: typing while g4lab was posting, some tips repetitive
Do you have the instructions of the lamp house?, I can provide you a link or pdf
To set Köhler illumination and center the lamp you need no frosted glass, but at the collecting tube inside the Zeiss microscope base there is one that can be switched in or out with a hex key
I see the lamp way out the center, even if you can focus it rightly its mirror image will be likely defocused. There are round smaller lamp holders that could fit better.
The lens for HBO arc lamps is different (more dioptric power) than the one for halogen, although with a LED with a size similar to the square lamp filament I find the HBO lamp collecting lens working better than the halogen model for true Köhler illumination.
To prevent heat damage look for a heat filter, there are two main types: old style transparent very light green glass and metallized reflective "heat mirror"
EDIT: typing while g4lab was posting, some tips repetitive
Pau
Thank you guys.
I will immediately ditch the 300W lamp.
If I understood correctly, I should get a 20-50W halogen lamp (voltage is not important, since I have control over how to power the lamp) and center the socket as close to the center between the mirror and the condenser as possible (the distance changes because the condenser moves back and forth)
Pau, thank you for the offer of a pdf. If you send it I will appreciate it.
I don't have the original socket for the arc lamp, so I have to find another light source.
You mention a LED source...do you mean to install a single LED chip (say 3W, 10,000K) pointing to the mirror? the size of the LED is about 1/4-1/5in round. Wouldn't that project a dark spot in the middle if pointed towards the mirror? Should I ignore the mirror altogether and build a 3x3W LED cluster pointing towards the condenser?
Since the arc option is out of the question, what would be the second best?
The reason I am rebuilding this lamp is because I acquired a couple of Zeiss Standard microscopes (one with the fluorescence adapter) and it looks to me that it's a pretty universal machine. I can see that there are a lot of adapters and options for it in ebay, etc. If I can bring one of them to a half decent condition I can use it for polarization microscopy, DIC, etc., can't I?
I will immediately ditch the 300W lamp.
If I understood correctly, I should get a 20-50W halogen lamp (voltage is not important, since I have control over how to power the lamp) and center the socket as close to the center between the mirror and the condenser as possible (the distance changes because the condenser moves back and forth)
Pau, thank you for the offer of a pdf. If you send it I will appreciate it.
I don't have the original socket for the arc lamp, so I have to find another light source.
You mention a LED source...do you mean to install a single LED chip (say 3W, 10,000K) pointing to the mirror? the size of the LED is about 1/4-1/5in round. Wouldn't that project a dark spot in the middle if pointed towards the mirror? Should I ignore the mirror altogether and build a 3x3W LED cluster pointing towards the condenser?
Since the arc option is out of the question, what would be the second best?
The reason I am rebuilding this lamp is because I acquired a couple of Zeiss Standard microscopes (one with the fluorescence adapter) and it looks to me that it's a pretty universal machine. I can see that there are a lot of adapters and options for it in ebay, etc. If I can bring one of them to a half decent condition I can use it for polarization microscopy, DIC, etc., can't I?
Here you have lots of Zeiss manuals and brochures: http://www.science-info.net/docs/zeiss/
This one is for lamp house 100 http://www.science-info.net/docs/zeiss/ ... tor100.pdf
You need a microscope lamp (square filament, right position...), not a generic one. Look for one of the recommended models.
Here you have links to the LED I use and its driving electronics:
http://www.photomacrography.net/forum/v ... p?p=197545
Because a LED only emits towards one side the mirror has no sense, you need to place the LED at the expected position for the lamp filament facing to the lens
This one is for lamp house 100 http://www.science-info.net/docs/zeiss/ ... tor100.pdf
You need a microscope lamp (square filament, right position...), not a generic one. Look for one of the recommended models.
Here you have links to the LED I use and its driving electronics:
http://www.photomacrography.net/forum/v ... p?p=197545
Because a LED only emits towards one side the mirror has no sense, you need to place the LED at the expected position for the lamp filament facing to the lens
Pau
NOTE: I don't use the whole lamp house with the LED, only its focusable lens module with a custom adapter for the heatshink-LED module.
Here you can see a setup that uses it but with a lower power LED:
http://www.fluorescencemicroscopy.it/en ... o_led.html , second half of the page
I also have the Lamphouse 60 adaptation designed by member 75RR
Here you can see a setup that uses it but with a lower power LED:
http://www.fluorescencemicroscopy.it/en ... o_led.html , second half of the page
I also have the Lamphouse 60 adaptation designed by member 75RR
Pau