Flat panel LED lights

[Temp]

I'm considering making a backlight for a fused glass art panel. Main concern is how to get a uniform level of illumination without spending a lot of time experimenting with led strips, reflective sheets and diffusers.

 

It occurs to me I might be able to modify an LED flat panel ceiling light. 

 

I know some of you have tried them. Can you see the individual LEDs throughout the diffuser or are they pretty uniform?

[PeterW]

They actually work by lighting the edge of the diffuser not as a slab of leds. You could do the same with a piece of sandblasted glass - how big is the piece ..?

[Alex]

how big a panel? 

Could something like this be made to work? https://www.energybulbs.co.uk/kosnic+12w+2d+4-pin+led+-+cool+white/465781742

 

[Ferdinand]

5 hours ago, Alex said:

how big a panel? 

Could something like this be made to work? https://www.energybulbs.co.uk/kosnic+12w+2d+4-pin+led+-+cool+white/465781742

 

 

What happens to those when those LEDs start popping, and how will performance be affected by time on or number of times it is switched on?

 

I have not had a good experience with LED replacements for some type of bulb claiming tens of thousands of hours. GU10s have been great and last for a long time, but some other types seem to die much more quickly. OTOH that panel is inexpensive.

 

Given that LEDs run cool, could you use something like a stick-on window-film on normal glass to diffuse the light behind the artwork?

 

I am sure some on BH have offcuts they could send to be played with once you know your size. I am sure I have some Rabbit-Goo frosted-roll left over somewhere, for example.

 

Does it need to be dimmable?

 

OTOH this 36W 7mm deep 600x600mm at 400k colour temp one comes for a similar price as the naked one you link, with a 5yr guarantee and an extra dimmable option mentioned.

https://www.elementlighting.co.uk/commercial-lighting/led-panel-lights/36w-led-panel-light-600mm-x-600mm-with-5yr-warranty-cool-white-4000k

 

(GOOGLE5 for 5% off)

 

Ferdinand

 

 

 

Edited September 22, 2018 by Ferdinand

[RandAbuild]

I bought 6 of these 36W LED Panel Light 600mm x 600mm panel lights when we started our build. One went into each room and they gave out a fantastic, even bright light, with little shadow. Most of our subbies were amazed by the light they gave out.

They've now moved into the garage, where two panels are quite sufficient to light up a double garage. You can't see individual LEDs as they light the edge. Recommended!

[Ed Davies]

@Ferdinand's link says:

 

Quote

Class II driver
Class III panel

 

I know what Class II is (double insulated, doesn't need earthing) but what's Class III? SELV?

Edited September 22, 2018 by Ed Davies
Link to Wikipedia section on SELV.

[Jeremy Harris]

16 minutes ago, Ed Davies said:

@Ferdinand's link says:

 

 

I know what Class II is (double insulated, doesn't need earthing) but what's Class III? SELV?

 

Yes, it's SELV.  These LED panels qualify as the driver is separate and mains powered, but connected by a low voltage cable to the light itself. 

[Temp]

I haven't purchased the glass panel yet but it will probably be around 600mm X 200mm.

 

I've just found 600 X 600 panel on eBay for £22 so might buy one to diassemble for parts and ideas. Claims to be 45W dimmable.

[Temp]

This is the sort of think I'm thinking of...

 

https://www.etsy.com/uk/listing/236473849/wave-in-a-frame-free-uk-shipping?ref=related-7

 

https://www.jazzitupinteriors.co.uk/acatalog/FUSED-GLASS-WALL-ARTWORK-PANEL-JDORGASTR_6020.html

 

 

[Temp]

In the end I ordered a "46W" 600*600 panel off ebay and it arrived today. Listing says it's dimmable, packaging says non-dimmable. Have contacted seller but it doesn't bother me as I got it to take it apart.

 

In case anyone is interested..

 

Inside there are two strips of about 96 LEDs each making 192 LED in total.  The power supply is a 1A constant current at 50V max so they must be arranged in 16 strings of 12 LED or something like that (12*3.3V = 39.6V). 

 

The diffuser comprises three layers:

 

Lower translucent white sheet

2.5mm Transparent sheet with textured surface (edge lit by the LEDs)

Opaque white backing

 

Behind that there is a 2-3mm thick foam layer which seems to be only used to fill a void. So the whole thing could be even thinner than it is. The whole lot is retained by a thin sheet of aluminium and about 24 self tapping screws. If I ever need some think aluminium for one of my model planes this might be a source.

 

Not a lot of insulation between the LED strings and the metal frame. 

 

Power supply has Pout:44W marked on it (not 46W).

27-42V 50V Max

Constant current 1050mA

Short circuit Protection

 

So I could reduce the number of LEDs to str if I decide to cut it up to make a smaller back light.

 

 

 

[ProDave]

The construction of that is exactly the same as the LED backlight system employed in a lot of flat screen LCD tv's.  I have stripped plenty of those down in the past.