Hi all,
So I have a question: now that we have those LED chips that can emit very bright and relatively cold (in temperature) homogeneous light (for example the design of general purpose spot lights) close to the condenser aperture plane. Is there really a need for the collector lens and optics?
Cheers
Question about illumination/colletor lens
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smollerthings
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apochronaut
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Re: Question about illumination/colletor lens
You are still starting with a small almost point source emitter, so it depends on how good a microscope you want. If you just want a microscope that can do 400X , then the answer is a qualified no. If you want 400X with resolution to match the aperture , then some collimating optics, yes. If you want a high N.A. microscope, with high magnification, using a point source emitter will require a collimating optical system for the illuminator. Colour temperature will need careful attention.
Another option would be to have an led source that had similar radiating properties to a gas flame or ribbon filament, such as formerly used In the late 19th century for research grade illuminators. Collimating optics would still be necessary but would need be designed to make used of critical illumination parameters.
The way around collimating optics is to go the other way and make an led light source that mimics the sky, which was the original light source that allowed for high N.A. microscope optics. If your light source is broad enough, .even enough and bright enough, then collimating optics are unnecessary. One could even see the possibility for condenserless under certain conditions.
Another option would be to have an led source that had similar radiating properties to a gas flame or ribbon filament, such as formerly used In the late 19th century for research grade illuminators. Collimating optics would still be necessary but would need be designed to make used of critical illumination parameters.
The way around collimating optics is to go the other way and make an led light source that mimics the sky, which was the original light source that allowed for high N.A. microscope optics. If your light source is broad enough, .even enough and bright enough, then collimating optics are unnecessary. One could even see the possibility for condenserless under certain conditions.
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smollerthings
- Posts: 457
- Joined: Thu Aug 19, 2021 12:10 pm
Re: Question about illumination/colletor lens
Thoughtful answer as usual 
My thought was on your last point. I was looking at the spot light in my bathroom and it is very bright and even. I took one apart and it is basically a ring of ribbons with a transparent deflector in the middle and a white reflector at the bottom. It is powerful enough for 40x for sure, 100x also but the one I have is only 3w. But I think one cannot go too high a wattage in this configuration because of proximity to sample.
Anyway, my question is hypothetical. Maybe could be useful to convert mirror based microscopes or those whose original illuminators have been lost.
My thought was on your last point. I was looking at the spot light in my bathroom and it is very bright and even. I took one apart and it is basically a ring of ribbons with a transparent deflector in the middle and a white reflector at the bottom. It is powerful enough for 40x for sure, 100x also but the one I have is only 3w. But I think one cannot go too high a wattage in this configuration because of proximity to sample.
Anyway, my question is hypothetical. Maybe could be useful to convert mirror based microscopes or those whose original illuminators have been lost.