15:48 Sep 8 

Thanks a lot... yes I noticed the typo when I pressed "send" - I used "les trois couleurs... produisant les pixels" but "qui constituent chaque pixel" would be great also... Thank you very much

14:28 Sep 8 

'In' is certainly correct in EN, though i'm not quite so sure about 'dans' in FR — there is no really notion of 'inside' the pixels, it just basically means that each pixel (more as a notional thing than perhaps actually physically) is made up of 3 LEDs; I wonder if you can't use some sort of formulation like "...qui constituent chaque pixel"?

Do also note the small typo in your proposed translation: it should of course be 'couleurs' in the plural.