Outdoor Magnifying Lens for U.S. Government Project

Can you explain more what you mean by "magnifying the light"? You can use a lens to focus the light onto a smaller area, but you won't be increasing the total light output.

Hello John

I do need to increase the light output. I figured if "lighthouses" have had a "magnified" type of glass for years than the technology is available..may be not. It would get this project out of a bind if someone has any idea of this type of glass exists.

thank you

But with a lighthouse, you're only illuminating a very small area at a time. The lens system rotates to sweep a beam out to the horizon, so an observer just sees a flash as the beam passes.

Are your lights illuminating something (as in street lighting), or are they being looked at directly (as in traffic lights)?

Hi John

They will not be looked at directly unless someone makes a point at looking at the light source ( the fixture), otherwise they are task lights. They are in fact illuminating flag poles, buildings, columns and large trees.

I really appreciate your kind help.

Bob

Are you using an appropriate reflector?

First question,

Why if these times of dwindleing energy, would you want to light up trees, buildings, etc.

isn't it bad enough already that in the USA we waste billions of dollars of energy every year on such sad lighting practices?

Check out the internaltional Dark Sky organization.

I myself would feel embarrassed to even think of doing such a job.

such a stupid waste of energy.

Hi,

Lighthouses use an amazing advance in optics called a Fresnel lens after the French inventor, perhaps this avenue may be a part of your solution, but grinding/moulding a new magnifying lens sounds very expensive and would NOT increase the light output. I trust you have exhausted your investigation of LED's? This would seem the most logical path to me. Cheers, TC

Having visited a few lighthouses over the years, I am told they use Fresnel Lenses. You might try googling that subject area or checking it out on Wikipedia. My 2 cents worth.

Mr. Gentry,

This is very unclear to me. I'm almost sure someone can help, but just need a little more detail.

What sort of architect are you? Do you have a EE PE on your staff?

Can we get a copy of the specs (I believe you said the contract has been let, so there's no competition problem).

Looking at what you want to do i would suggest you get in touch with the architect in charge for the the lights of Paris (France-Europe) they have an excellent experience in the field you describe for instance the lights for the Eiffel tower and all the historical buildings in the downtown. i think you could get a good support. Paris is called also "la ville lumière" which means the "light town".

Of course if it is politically correct to ask for an European solution.

Hi, Bob
As John says you can't magnify the light.... you can just move it about or direct it where you want.
If you give us more specific information we can help better.

The only solutions (IMHO) are.

1. Increase the power output of the light-source (bulb).
2. Increase the number of light sources.
3. Direct (focus) the light more accurately so that it only illuminates your 'target' and avoids any 'wasted' light. (this is generally done with reflectors rather than lenses).
4. Prove that the results achieved are in fact consistent with what was specified and are perfectly adequate. (This may sound flipant...but measurement of light levels is a tricky business and unless they were correctly specified in the first place....)

I shall omit #5,6,7 as you have already had enough mad humour from a guest....(drat, I thought that was my job )

Del

Del, THAT is an intelligent answer! I couldn't conceive of "magnifying" light, unless one were going from a large light source to a smaller area. I have heard stories about "some kids" roasting ants with a magnifying glass and using sunlight.

Contact an electrical engineering firm in your area. Our firm does lighting designs for architects in Washington and Idaho. there is a fixture for your needs and the electrical engineer doing lighting designs knows what it is.

Sounds like your problem starts with the reflector as has been suggested earlier. If you are trying to illuminate specific objects you would be using a parabolic reflector which in turn works best with a point source of light. Sometimes reflectors are given a 'hammered' type of finish to remove banding effects but this tends to diffuse the light output.

I think that, rather than using a lens to patch the problem, you need to look back at the source of the problem. A lens might be able to concentrate the light into a smaller area to increase the brightness but will also give you some losses.

Hi Bob:

They used some type of mirror system at Lowe's Motor Speeway to illuminate to racetrack for night races. It worked good. I think it has been done at other tracks also, including Daytona. You might check with them.

Indydog

The good news is that can use your existing lights and increase the illumination intensity at the target area. This can be accomplished by focussing the light and scanning. The peak intensity can easily be doubled, but the target will be illuminated slightly less than 1/2 the time.

Twice the intensity for half the time...
So on average that'd be exactly the same then?

You are precisely correct. However, remember that a camera flash doesn't increase the average illumination by much at all, but it provides intense illumination for the period the intensity is required.