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What would be the best way to redirect LED light in a limited space (as esthetically possible)?


LED's will be mounted in a wooden frame that is about 2 inches (50 mm)  in height, facing at a right angle to the object illuminated, but mounted "normally" in the frame (through hole).  BTW, the "light" included in some of the LED's will be near IR and UV.
SO, I need any light "escaping" to the "other 3 directions or sides" of the LED, redirected towards "the fourth side".   

No, I can not turn the LED's, at least I don't have a way at this time to and still distribute the output evenly.

I've included a little sketch of what I mean.  The "viewer" is positioned from Your viewpoint, the width of the frame I have above is the small area I have to work with, and I don't want the "solution" to be esthetically UGLY either if that can be avoided.

Picture of What would be the best way to redirect LED light in a limited space (as esthetically possible)?
tomtomtom552 years ago
After wasting lots of time and money, I've found that craft store acrylic rods work just as well, for "light pipes" and similar purposes, and cost practically nothing.

The way that flat panel backlighting fiber optics are made is quite simple:
A bunch of strands are held together by some clear shrink tubing, to collect light at the LED source.

They are then spread out horizontally, along the height (or width of the screen to be backlit.
Another set of light-conductors are "braided" perpendicularly to these.
In order to get the light to come out from the sides of the acrylic, they can be sanded (fine grit) at an angle, getting narrower as it extends farther from the light source. This is especially important when the perpendiculars intersect.

Behind, and at the 3 edges which aren't coming from the light source, you will need something reflective. I find reflective safety tape works well.
Behind the entire panel, you will need a larger, uniform reflective surface (somewhat diffusing, not mirror-like). Trial and error will find SOMETHING useful.

In front of the panel, you'll need some diffusing material.

That's just about it. It's easier than I may have made it sound; I tend to over-explain things.

Good luck! I hope this helps.
Goodhart (author)  tomtomtom552 years ago
Thanks. This project I was working on, an ible I have already published, required light in front of the object (in this case a t-shirt) but behind another pane of glass. My project never really achieved what I had hoped for however, but I did get the UV lighting to work relatively well.
seandogue3 years ago
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Goodhart (author)  seandogue3 years ago
This is an interesting solution too. Will the light coming from a light pipe be very concentrated though? I do definitely lean towards some form of reflection as you and Burf have suggested.
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Goodhart (author)  seandogue3 years ago
The "frame" I have in my illustration will be around 12 or 14 inches by about 18-20 inches with a glass front.

With as few LEDs I am trying to illuminate (from the frame) the flat object inside the fame.   I want it to be viewable in 3 different modes but I only had enough to purchase about 9 LEDs of each kind except the bright white ones. 

I am looking to create a bit of a special effect with the different sets of LEDs, some making the object "visible" to a digital camera, for instance, without the need to flood it with light that may damage or fade the object's colors etc.

I have already created the wire harness, and planned where to place the LED's around the parimeter, but the light is very local, and some of it glares off the glass (ergo the need to redirect that portion of it).

Sorry about the scale of my original drawing it is ALL wrong of course, the LED shown is WAY too big in comparison with the frame shown.

Hmm, the sound of your tube idea may be applicable but modified as (maybe) a half tube ? 

Sorry for withholding some  details, I have at least 3 ibles in my "to do list* unfinished that I asked about some detail, and they got finished, by someone else before I was able to complete mine....one of these days I will either delete them or modify them enough to be published as originals :-) 

So, yes reflection is what I am after, but not concentration of light into a small area.
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Goodhart (author)  seandogue3 years ago
I don't think I need to cut them in half....maybe if I just cut down the length of one side? That would open it up to allow me to use it as a kind of reflective shield....I hope new copper is reflective enough...
Goodhart (author)  seandogue3 years ago
I understand. I was hoping to be able to mount the LED's "up close" as in in the actual frame of the display case, around the outside, and reflect any light that would travel out towards the viewer, back into the displayed item.

It is very much like a picture frame, only a few inches deeper.  I want to be able to preserve the item as well as display it under several "conditions".  :-)

I have to use things I have at the moment, or cost VERY little....my thought,  was to take something shiney (and small) about the shape of a spoon (much like the reflectors they used on the old box cameras), and direct it that way, but the local craft shop doesn't have anything appropriate.  I think I shall take a quick walk through the local hardware store and see what I can "turn up" :-)
Goodhart (author)  seandogue3 years ago
I was thinking of using individual copper crimp connectors like those pictured, but I would need to first flare one end, cut them in half, and then attach them with insulation between them and the contacts (in case of accidental shifting). Seems like a lot of work for something that may not help much anyways.
Copper lugs.jpg
Goodhart (author)  Goodhart3 years ago
BTW, thank you for all your suggestions, I am greatly appreciative.
I have not experimented with this idea, but how about dipping the tips/side (area that needs to be redirected) in chrome paint. You may need to mount them first and carefully paint them with a brush. Testor's model paint may come in chrome, I'm not sure as I haven't done models in years. I have bought chrome spray paint within the last few years - either Krylon or Rustoleum brands - I know it was one of those names.

To use spray paint for dipping or brushing, spray an amount into a container - enough to dip the part or brush into. IIRC, you'll need to work relatively quick with this method.

Once you are satisfied with the results, you can cover the exposed chrome areas with black or whatever color needed to make them blend in. This is similar to what they do with glass mirrors (turn one over and all you'll see is grey, usually).

Good luck,

Qa
Goodhart (author)  Quercus austrina3 years ago
I was thinking the same thing....maybe painting the inside of a plate or small half a tube or something.
rimar20003 years ago
If the way is intricate, try to do a "glass fiber" using transparent hot glue. It is easy to try it.
Goodhart (author)  rimar20003 years ago
It would have to be very short, and still dispersed and reflected at the end, I am afraid. Although this gives me a idea to try.
There are semi-clear and clear hot glue , seek the clearest you can.
Goodhart (author)  rimar20003 years ago
I am still in need of "reflecton/redirection" of the light coming out of the sides of the LED, more so then what is coming out from the front dome. Otherwise, it would be a great idea :-)
That "reflecton/redirection" of the light is accomplished by the glass fiber. Besides, using hot glue you can do a "pick-up" around the led to capture all the light.
Goodhart (author)  rimar20003 years ago
I am not being clear, I am sorry. When you look at the "drawing" of mine, the portion of the LED the viewer is facing will shine light "towards the person viewing it:" which will glare off the glass a little further out from it between the LED and the viewer. So, I need to reflect the light from that direction and get it to go in the same direction as the rest of the light already coming form the LED.
iceng3 years ago
Certain materials fluorescent under UV light ( like linen ) Very blue white,
lm sure you already thought of that.

My thought,  it is worth a try to ring the inside of edge (height) of your frame
with the fluorescent materials (paints) of your choice to light your "objet d'art".
And a UV dispersing lens device at the LED.

The remarkable feature of UV light, is any light accidently directed to the
viewer cannot easily be noticed or seen until converted to visible light.

A final note there is a clear plastic sheet which could be your frame
window that fluoresces under UV light (I cut it into angel wings 4 night viewing)
It could provide overall alibet non-uniform (because of a single LED) lighting
of your target. You have to try and err, after all this is instructables.

A

Goodhart (author)  iceng3 years ago
Iceng wrote: Certain materials fluorescent under UV light ( like linen ) Very blue white,
lm sure you already thought of that.


(yep, that is the effect I want to get, so I want to direct the light towards the {don't tell anyone} t-shirt :-)


So I am in need of directing (in one case) the UV light right at the displayed object....so the object itself will fluoresce. With the IR LEDs, they will be make it visible to a digital camera, without having to "turn on the lights".

And the bright white LEDs are for normal viewing
Burf3 years ago
One-way mirror on the viewer side of the picture frame, reflective side facing the object to be illuminated?
Goodhart (author)  Burf3 years ago
That is an interesting, if not expensive solution, but it would have to be around the edge only, so the viewer could actually see the object displayed. :-)
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