Re: Double your light output with no extra heat
So how have our suggestions helped ?
In another thread I've done some calculations, based on analysis done by bbb74.
http://www.candlepowerforums.com/vb/showthread.php?p=3490781#post3490781
If you increase lens size so it captures +/-50 degrees instead of +/-40 degrees AND switch from an XP-G to an XR-E, the percentage of light captured from the LED increases from 44% to 94%.
Seems an easy way to achieve your goal in the original post, of 15% increase.
btw you never answered my question about the +15% goal. A person would have great difficulty detecting a 15% increase - is there some minimum lighting level you need to achieve to comply with an industry standard, or is it to match a competing product.
The 15% increase that is needed isn't necessarily exactly 15%, its just my estimation. Basically brighter is better, thats all. The current model needs to be a bit brighter in order to be useful. Its currently bright enough in the center of the spot, but dies off at the edges enough to loose its functionality.
I've taken everyones help into consideration and am now testing prototypes with the XRE R2 with biconvex and plano-convex lenses. So far tests have indicated that this is exactly what needed to be done. I cannot thank everyone on this forum enough. I hope to find a way to return the favor.
With the XRE, I've got 2 lenses that almost work perfectly:
Biconvex 14mm diameter focal length =12mm
Plano-convex 15mm diameter, focal length = 18mm (coated)
Both can produce the correct sized spot and at the correct brightness. Ideally the biconvex focal length should be between 10.5-11mm and the plano-convex somewhere between 12-15mm focal length. (both in 15mm diameter-largest apatite as Dr.Jones also indicated. Indiana Jones?:thumbsup
🙂 I cannot correctly calculate the perfect focal length though. I've tried all forms of calculations and have come up with little more than estimations.
I cannot for the life of me understand why first of all the plano-convex produces a much cleaner spot, and second, why a longer focal length plano-convex can produce the correct focus when compared to a shorter focal length biconvex. Clarification on this would greatly help.
The following is a picture of current tests and the lenses to be made. I greatly appreciate any input.
(Note: Diffuse focus because this is how it will be used. Spot on right has correct sized spot but too dark at edges.)
Plano-convex spot does not appear to be darker than the biconvex in real life.
There is a TON more information I've learned, but its too much for one post. For example, aspheric lenses are good, but have so many weird angles going on that they end up producing a good center spot, but the edges are significantly fuzzed at best. Also, why do smaller aperture biconvex lenses have a radius of curvature less than their focal length sometimes(this seems to be for very short focal lengths)? Why do plano-convex lenses act so differently when you place them outside their designed focal length when compared to biconvex? - all things that make it more difficult to even estimate the proper focal length. Basically I don't know if these new lenses will have too short of a focal length or now and have no idea how to judge.
