Light Alternative?

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gdcross

Member
2002-05-30 2:16 am
I've been reading a lot of the posts about lights so I'll throw this at you because there's a lot of pages (which I don't have to time to go through right now) to read to see if it has been mentioned. a search didn't come up with anything.

I see that a lot of people are using mercury vapor bulbs. Most of the mercury vapor bulbs burn toward the yellow visible spectrum (really simplified). A suggestion I submit is using lights that are used in salt water aquariums. The Very High Output (VHO) and Metal Halides (you want the daylight bulbs) are in the high white spectrum and are very 'bright'. The electronic ballast that you will require for the lights are expensive, but they come in kits which include a reflector (conic or flat - your choice) or the parts can be purchased separately. The upside is that they last a long time and since you're not worried about a slight loss in light over time, they should last several years.

The electronic ballasts run very cool (the Ice Cap ballasts I can attest too as two of them drive my VHO florescents on my 375 aquarium) and are easy on the electric bill. There is no need to have a fan for them (you will for the bulb area), they run that cool if not enclosed. They look good too, so you may not want to cover them for the coolness factor. They also have minature florescents. If you want more bulbs, you can gang them if you get the right ballast. Warning - these ballasts are not cheap but beat the cheap ones both in cost of use and mean time before failure. I've had my two ballast for nearly nine years and no sign of quitting or bad power output (blackened ends of flourescent tubes).

The metal halide bulbs are also small, not like the hugh bulbs that are typical for mecury or outdoor halides. That will save you a lot of space inside that cabinet.

The down side may be that the lights may be too high on the UV side (certainly the actinic bulbs, which are like a blacklight and not what you would want) but I don't think that it would cause any problems. Bulbs are rated from 5000 Kelvin to 20,000K for metal halides. If you've never seen one of these bulbs in action you will not believe how bright they are. Hey, they are supposed to simulated noon day sun for deep water tanks (water absorbs light like you would believe).

Search for marine aquarium specialists to see the varieties of lights that are available.

Anyhow, you can visit the Ice Cap website at http://www.icecapinc.com for a recommended electronic ballast. They have a good reference for their products. Yes, I've got a lot of experience with this type of lighting, if you were wondering.

Hopefully this helps or gives everyone a new route to think about light sources. Good luck to all of you and maybe I'll join you ranks for DIY'ers. Got to admit, some of the stuff you're doing is very interesting.
 
Just the person to answer my question

What color is a Ir filter? Or, an Ir/UV filter?

We use these in our slide projectors I believe, but , we don't know which one is actually the filter. As, there are many lenses in them can you help to resolve our query?

Also, is a mirror that reflects visible light and absorbs the rest the same? Are there any positives to one rather than the other approach?

Thanks in advance!
 

gdcross

Member
2002-05-30 2:16 am
Interesting question. Maybe I can answer it.

When I was and Infantryman and we were switching to the passive Night Observation Devices (NODs), all the active NODs had IR emitters to provide the light source. The IR filters in those devices were red in color. The xenon lights on the M60 tanks also had IR capabilities with the IR filter installed over the light. I unfortunately did not have an opportunity to see what color the filter was (the lights on the M60 were 1 million candle power I think - truly spectacular when turned on in the desert night). To make a long story short, an IR filter lens can be clear also. I refer you to IR LEDs which can be used with surveillance cameras which have clear 'lens.'

The question on your slide projector I'll have to give some thought and research too. How to tell the difference I couldn't really say at the moment. If it were used to filter light, then it really doesn't make any sense to create a lens; a flat piece of glass would serve the purpose of a filter and be cheap. I wonder if the lens are optically coated? If I may ask, does it really matter? - which the second answer may answer.

A 'cool' reflective surface, in this case a mirror, is designed to reject IR lengths which are heat producing. The positive is that there would be a decrease in (forgive the awful description) 'thermally - or heat producing' reflected light. The positive is less heat generated from light on the receiving end (your LCD). The negative is the loss of a little light but I doubt significant to worry about. I would ask is the cost of a cool mirror worth it? I somehow think that it wouldn't be since everyone is using glass barriers with fans to dissipate heat. Do they make an IR glass coating (for automobiles) that is clear? This could be something to consider if IR is a problem.

I'm not sure I helped any. I'm more concerned about the quality of light that gets to my corals in my tanks. If you would like some more technical information on MH light try this website:
http://saltaquarium.about.com/gi/dy...w.sasala.com/fish/lighting/new-lighting2.html
Click on 'Reef Lighting' on the menu to the left. It has some good information on MH lighting (technical and layman) and constructing lights.


If you're wondering about all the Kelvin ratings here is a good example of how Kelvin (K) rates against sunlight:
Kelvin Light Sample Color
5200 K Sunlight Blue
4000 K Xenon HID Blue-white (Like those Halogen
lights on cars)
3800 K White
3200 K Halogen Yellow-white
2900 K Incandescent bulb Yellow

Mind you - although this is a general chart - MH bulbs for aquariums called 'daylight' bulbs are bright bluish white light and more bright white than blue to myself.

Good Luck!
 
gdcross,

Apologize for not explaining before and thank you for your knowledgeable response.

We were trying to ascertain the physical look of a Ir glass/lens in the slide projectors we use in the "DIY Small Panel Projector" thread. After we find out what's what we should be able to start a comparison experiment.

Some of our projectors use the mirror approach and others use the glass/lens approach.

We were trying to find out for our "prototype" box, if one had advantages over another.

We were able to conduct a simple glass and remote control test to find one Ir filter (a flat glass with a greenish tint). We think this would be a good way to confirm it's being an Ir filter.

I personally felt the mirror approach was the superior Ir cleaning device but, not sure how to evaluate as we haven't performed a controlled experiment. Nor, have we any data on the percentage loss of light for glass vs first surface Ir passing mirror as well as efficiency of absorption. However, the more expensive projectors I've seen use the mirror approach.

We utilize the small panel lcd's and heat seems to be the major issue on these. So, finding the ideal DIY approach to the Ir heat problem is our major concern in making our setup.

Thanks for letting us bend your ear. This certainly helps our investigation!
 

gdcross

Member
2002-05-30 2:16 am
A quick thought on a filter vs the mirror. Energy efficient storm windows on homes use an extremely thin IR filter sandwiched between the double panes. I'm going from memory but I think the reduction in IR from sunlight was somewhere around 30%. The loss of light was 3 to 5%? Not a bad tradeoff. Before you think it - I have too many hobbies.

The light which comes through our window does not appear to have any tint and is as bright as the old window. Sorry but that's about as scientific as I can get it for you at the moment. But I'm certain that there are spec's on the filtering capabilities of this material. Now that I think about it, perhaps I should be talking about UV and not IR, which makes my point irrelevant?

I confess, you've thought of things I would never have considered or probably bothered with. Then again, if I were building it, I would probably be attentive to the details as all of you are. If I find anything that might be helpful I'll pass it on.
 
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