Optics the future for lights?

I was reading about prisms and why they are used in binocs and telescopes because they have 100% (internal) reflection, instead of 90% reflection for a reflector, which decreases as the reflector gets dirty etc.

Then i got to thinking about our beloved Luxeons and their optics - they all act as prisms and collimate the light because of internal reflection from the sides of the optic.

Of course, this is subject to proper placement of the optic - if it is not placed correctly (at the critical angle) there will be almost no reflection.

So does anyone else think optics are the way to go for high efficiency applications, replacing reflectors as LEDs become smaller point sources of light?

Hmm... i wonder how a big-*** optic would do to collimate the beam into a tight far-throwing spot. /ubbthreads/images/graemlins/thinking.gif

I don't know what form they will take, but I believe that there is an entire "optical frontier" waiting to be explored. Personally, I envision a tiny "monocular" device with a LS positioned where the human eye would normally go. Sort of a scaled down version of what is presented here: http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB1&Number=394616&page=0&view=collapsed&sb=5&o=1&fpart=1

:shrug: Looks like optics have moving to the back burner lately. Does anyone here think that optics will still be used in lights? I myself am building a Mag tri Lux and will be using optics. More just to compare beam quality against reflectors.

There have been some interesting threads recently about this. Here is one, in case you haven't seen it:
http://candlepowerforums.com/vb/showthread.php?t=155504http://candlepowerforums.com/vb/showthread.php?p=1912059#post1912059

SureFire's new TIR optics for their Cree XR-E models are the first production model optics that beat what a reflector can achieve in the same bezel. I am extremely impressed with how far SureFire have developed TIR optics.

Al

Yes I read that thread DM51. I think I was mostly refering to retail lights. The use of asphrerical lenses has rekindled the use of optics for sure. Back in 2003, there were numerous lights using optics. Today, the use of optics has been replaced with reflectors.

I absolutely agree that optics will be MUCH more efficient than LEDs, reflectors only have about ~88% reflectance, more like 75% when taking into account lens losses and oxidation etc. TIR optics can transmit almost 100%.

Another thing to consider is that with the LEDs, the reflectors can only capture a fairly small portion of th elight, a lot of it spills out the front. In the case of a light that is to be used at close range that's fine, even an avantage as it lights up peripheral vision fairly well. In the case of a light to be used for throw however, all the light that spills out the front is essenitally wasted. With good TIR optics though, ALL the light from the LED can be collimtaed into a beam, whereas even with some of the better LED lights today, probably little more than 50% of the lumens are focused into the beam.

I think a beam with a sharp hotpsot, and gradual "taper" with some spill is ideal, and can be accomplished nicely with good optics. What I would like to see is some sort of focusable light using compound optics -- TIR to project a tight image of the LED (almost 100% of the light) into a big collimating lens such as an aspherical or fresnel lens. The secondary lens could be moved back and forth to adjust focus. Though I haven't built a light with it, I have a Cree that I accidentally broke the dome off of -- with a lens I can focus the light from that into a tiny poinpoint, a good optical system like the one I described could throw extremely well, and even designed to produce some spill, and be de-focusable for more flood.

It's funny how things swing around after a couple of years. Maybe we will see less people placing reflectors into their KL1's.

The new E1L and E2L with the new KX1 bezel (Cree XR-E behind a new TIR optic) will not need to be modified to a reflector in order to get a great beam.

Al