chatting about: back lighting with LED’s!

[Phill Fenton]

This sounds like a really interesting project Joe. Some time ago I was asked if I could produce a sign consisting of 3 dimensional hollow letters -backlit to produce a “halo effect around each individual letter. I did’nt have a clue where to begin so I politely declined to quote for this. I look forward to hearing more about how these kind of jobs are done. 😀

[Martin Pearson]

Its really quite easy Phill, the letters can be almost any material but obviously with a solid face so the light doesnt escape out the front, the backs of the letters is made from clear acrylic, and the light source (normally neon) sits inside the letter mounted on the clear acrylic back. The letters are mounted the same way other individual letters are mounted.
Almost the first job I did as a signmaker was for a nightclub, 500mm stainless letters with 100mm returns, backlit with electric blue neon to give halo effect.
Looks really good if I do say so myself.

[Paul Davenport]

Who’s LEDs are you using JOE

Nice to see that im not the only one playing with LEDs, we are building some signs for a customer, aluminium built ups spanning 27meters, red halo effect using white inGaN emitters shining through transparent red backs

All running from 24v switch mode transformers

Joe what sort of lumens per meter do your emitters output, the ones i have decided to use are 180 Lpm, and consume 1.2 watt per unit.
They are single emitters mounted to an aluminium PCB/heatsink

[Joe McNamara]

Lumens per what…emitters 😮
Blimey …bit hi tech or what?
Seriously though, I’m experimenting with some hi intensity blue LEDs and a 12v transformer from maplins electronics….5 leds in a channel letter (with a 35mm return)letter “L” about 7″ tall with the leds pointing backward through a white acrylic back of the letter to diffuse the light. Says in the maplins book they’re suitable for sign illumination…and they’re wired in parallel with a resistor at the start between the transformer and the leds…if that makes any sense 😆
I got the very helpful bloke at maplins to work out the resistor value and the transformer settings….currently 4.5v for the 5 leds but he said I’ll probably need to crank it up to 12-15v for the finished sign. Anyway, I just showed the mock up to the potential customer and he loved it so Got the order at a decent price. Any tips or advice would be appreciated as it’s a new toy to me Paul…but gives a great effect for lighting.
Cheers mate
Joe

[Martin Pearson]

Hi Joe, couple of questions if you dont mind.
Were you playing around with this idea before the customer asked about it or is your experimentation as a result of an inquiry ?
Do you have any experience with electrics/lighting or is it all down to your time as a signmaker.
And finally you said that the back of the letters was white acrylic, does enough light shine through the acrylic or is it what I know as opal acrylic that the backs are made of.

[Paul Davenport]

Joe

I can give you tons of advice about this subject, but its better for you to ask specific questions really as i think i could get to deep on the subject.

Basically (i may be wrong here) but I guess the LEDs that maplins sell are of the dome type with the two wires coming out the bottom, really cheap to buy, we are using a slightly different item, manufactured by a company called luxion in the US, it is a Aluminium PCB with the white inGaN emitter in the centre, each item is connected in series by IDA connections which allow for easy installation in a letter

the sign i mentioned will use around 1500 very high intensity white emittors costing around 6.00 each, roughly 9 grand in LEDs alone !

I have been looking into alternative lighting (to neon) for about 3 years or so now , played with fibre optic lighting in some 3 metre high built up letters for the Manchester Evening News Arena, which was an unbelievable amount of labour involved
And ive been looking in on the LEDs for a while, waiting for a marked improvement in light output before id take the plunge and buy some

I will put some pics up for you to look at, but for now if you need to know anything else, please ask