One of the great things about the last few months has been sunny weather, and the chance to build outside during the day, rather than just inside at night (Quick reminder for northern hemisphere readers, it is summer here, and holidays finished only a couple of weeks ago). What became apparent is that when building under sunlight, the trans fluoro reddish orange elements (also called Trans Neon Orange on bricklink) tend to become brighter in the sunlight, with an eerie glow. This was not obvious when working under an incandescent lamp at midnight. It turns out that these transparent fluorescent colours are, intact, fluorescing.
What does it mean to demonstrate fluorescence?
When light, or other forms of electromagnetic radiation, strikes a substance, the energy is absorbed. Electrons in the outer shell may be excited, and move to a higher energy state. As these electrons return to their native energy state, energy, typically in the form of light is given off. This light is of a longer wavelength (lower frequency) than that of the light striking the substance. Some substances are more prone to this than others, especially in the case of ultraviolet light. It can be observed with many minerals.
Why do these elements look a little different in sunlight? Sunlight is not just white, visible light (which Newton demonstrated to be made up of all the colours of the spectrum), but also includes ultraviolet and infrared light.
Fluorescent lights are dependent on the UV light emitted by heating (typically) mercury, and the emitted light causes the tube’s phosphor coating to fluoresce.
Here are some of my Transparent elements exposed to regular LED lighting, and to the ‘white fluorescent light’ from my light box. You can see traces of the fluorescence with in this second group. The third image shows the same image taken, with only UV lighting.
The UV lighting here is provided using an ultraviolet LED from an electronics supply shop, and a coin shaped battery, as has been shown previously. This light can also be tucked away inside a MOC featuring transparent fluorescent elements, to enhance the fluorescent effect.
Here I used a little ‘white light’ in conjunction with the UV light, to give an eerie feel to a NEXO Space tanker making its way across an alien landscape.
Have you taken advantage of this property? It would seem that this is just crying out for exploitation in a MOC. If so, why not post links to it below, or share it on the Rambling Brick Facebook page.
4 thoughts on “You light up my LEGO – let it glow!”
[…] You may have seen my article last year on fluorescence in LEGO elements. […]
[…] Highlighting the front and back of the figures, and also look at them under an ultraviolet lamp, to see if we see anything interesting…After looking at Vibrant Coral ever so briefly last week, I wonder how they will all appear […]
Will exposing to UV light affect discolouration of bricks like direct sunlight exposure would?
I think it is unlikely to if the exposure is low powered, and for a limited period, eg a few weekend shows. Sunlight is much more intense, and has a broader range of wavelengths. But I’d love to hear a materials engineer’s opinion on itZ