Some kind of plastic needed

[martin54]

If you know where you can get lots of vinyl off cuts then ask them if they have any translucent off cuts or even frosted you can try. Translucent is what is used for lightboxes so allows more light through & frosted is available in different colours & will also allow more light through. Both have a matt finish which will help with the glare.
Don't know if these get moved about a lot but if you go down the sheet material route then polycarbonate might be a better option than acrylic, acrylic tends to be a bit brittle but make sure it is an exterior grade. Exterior grade is UV stabalised which stops it yellowing over time.

Another option if you are still experimenting & still have units to manufacture is to change the colour of the LEDs so they show up better during daylight hours.

[m_c]

This will only be getting used a few times a year, and will spend most of it's life wrapped up in a shed, so I'm not too bothered about UV stability. The ability to not fail in rain is far higher on the priority list!
It's going to be built into a box, so I'll make a cover to protect the front during transportation.

[martin54]

What are you going to use for manufacturing the box? Something like aluminium composite would probably work quite well, it's light & pretty hard wearing & you can fold it into a box shape fairly easily by routing a "V" grove to fold along. would reduce the number of joins you would have to worry about sealing.

[m_c]

Not got that far yet!

Main panel that holds everything will most likely be aluminium, which will then have the perspex mounted closely in front of it. Then all that needs a box around it. I might just go for something like ply for simplicity, then give it a good prime, and paint.
I've got somebody who could do the woodwork for me, which saves me time. If I go metal I'd have to do it myself.

[Swarfing]

Maybe the acrylic diffuser panels they use for the light units in paneled ceilings maybe a better bet?

[martin54]

Composite board has a thin aluminium skin with a plastic centre. OK it's a lot more expensive than say far eastern ply but the whole thing would be lighter & easier to move about, it's already powder coated so no need to paint & comes in about 6 different colours plus it's pretty easy to cut so your woodworking guy could still manufacture it for you. Normal woodworking tools will be ok as long as any saws are fine toothed, for small jobs I use one of those throw away laminate saws that joiners use & the V groove I do with a normal hand help router.
Not the cheapest way to do it but would look good & last for years.

[birchy]

Most of the old clock radios and such like used (brown/green) tinted acrylic to reduce the glare.

[Musht]

With Birchy, it`s a contrast rather than diffusion problem, dark tint will work better than a frost.

Amber LED might work better as well, high brightness, `sunlight visible ` are reliable and relatively cheap.