I'm new to this forum. This is half a question, half a challenge. And it's more engineering then physics but I thought I might get good insights from a physics forum.
I would like to cure a UV activated resin using a collimated $390$ to $420~\rm nm$ light source. The area I need to cure is $3$" ($7.5~\rm nm$) by $3$". ( although the light beam can be bigger then this area and of any shape) so long as it's collimated and as efficient and low cost as possible. I want to get at least $3$ watts of light power over that area and it has to have light everywhere and ideally as evenly distributed as possible. Ouff!
I'll have to build some sort of DIY apparatus to collimate light coming from $390$ to $420~\rm nm$ LED's.
There are different types of LEDs on the market. Single point high power ones ($1$-$3~\rm W$) with viewing angles $40$ to $160$ degrees (the angle at which the light cone expands out) or some even higher power arrays of diodes : $5~\rm W$+
Or low power $5$mm diameter ones with witch I could build a large array of evenly spaced LEDs. ( but not necessarily) these have viewing angles of $25$ to $160$ degrees.
In all cases, the actual light emmiting part is generally square and very small, then it is encapsulated in another package.
I don't know much about optics and I have been pondering about this problem for a while now.
How would you go about doing this? From lenses to mirrors, to what type of led to use, there's pretty much an infinite different ways to approach this and I needed to get the idea out there, so others could share their insight.
Feel free to throw any ideas but try to remain as technically and scientifically correct as possible.
Also, although the problem makes sense to me maybe I failed to share it with you appropriately, feel free to ask questions or clarifications!
EDIT: I intend to pass the light through an LCD screen before hitting the resin. Which brings me to another question. At these wavelength, will diffraction come I to play if the LCD "holes " the light is passing through are 100 microns large?
Edit wavelength can be between $390$ and $420$ blow that will damage the LCD. Above will not cure the resin.