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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)?
tomtomtom553 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)  tomtomtom553 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.
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 austrina4 years ago
I was thinking the same thing....maybe painting the inside of a plate or small half a tube or something.
rimar20004 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)  rimar20004 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)  rimar20004 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)  rimar20004 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.
iceng4 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)  iceng4 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
Burf4 years ago
One-way mirror on the viewer side of the picture frame, reflective side facing the object to be illuminated?
Goodhart (author)  Burf4 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. :-)