fiduciary

Author Topic: A Light Focusing Solution Thread  (Read 11091 times)

0 Members and 1 Guest are viewing this topic.

Offline Sunrider

  • Unlimited Brightness!!! RRROOAARRR!!!
  • Master Force User
  • *****
  • Posts: 585
A Light Focusing Solution Thread
« on: July 20, 2011, 03:59:21 PM »
This is a thread for people to share their experiences and knowledge about LED light focusing solutions. Master Yoda said it would be cool if we had a thread with info about lenses and I must obey my master.  :D

This is a stumbling block for our hobby because of the lack of choices of narrow beam LED products that actually fit in a hilt.

 Beam patterns and intensities are very difficult to quantify and compare even with fancy equipment so I will take a more simple approach on the subject to try and convey my findings on the matter. Besides the fact I don't have 2 of everything to compare side by side.  ;)

I have found a fairly simple way to tell whether or not a a lens or reflector can be a good match for a LED, and if it is worth trying to use. I basically look straight down the optic then turn it at an angle a bit and note what I see. Feel free to inject your opinion whether similar or different.
 

  We seem to be limited to two basic groups of solutions. Clear plastic lenses, and reflectors.

 Some fundamental differences that stand out to me regarding performance are.

Reflectors:
More difficult to get a even, narrow beam, free of hot spots.
More light lost to the side rather than straight out the front.
More available options.


Lenses:
Can make a tighter, evenly spread out beam.
Less available options.

Similarities:
Must be suited to fit a certain LED type exactly to work well.
Must have super smooth surface.
Must be positioned precisely in the right spot.

Here are some examples to support my findings and to show a simple method I use to tell if a solution should work or not. You can right click and view image to see bigger pic.



Here is a LEDEngin 10w. With this reflector if you look straight at the LED you can see the reflection of the 4 dies off  the reflector ok. This tells us that most of the light will go where we want it to. But the dead dark circle around the led dome shows that it isnít a great fit for the LED.



This is an example of a poor reflector. The surface is polished but the texture sends the light in all directions. And the dark circle again.




Here is a good clear lens but poorly positioned. The 4 dies in the center are mostly in focus but the lens is mounted too high and you canít see much reflection of the dies around the outer part. And a dead circle around the dome again.




Here is a really bad lens. You can barely see any trace of the dies anywhere and what you can see is all distorted. Unfortunately I donít have a good example of a 10w with a lens I wish one of the makers would do one and keep it available.




Here is just the wrong lens. The outer portion looks great showing the center of  all 4 dies but the middle is completely dark.




This is why the reflector has a more difficult time with making a narrow beam. The line of sight off the dies limits them to around 50 degrees. It can only focus the light it can catch it around the sides.




 Its hard to see here but this is a rebel with the 8 degree lens. From the front you only see parts of the die no dead dark spots at all. Thatís why these work great.




Here is the same thing off to the side a little. Already the die is hardly seen anymore and dark spots appear. This signifies that the lens creates a pretty narrow beam.





Here is a SSR90 with a good aluminum reflector setup. I took it out of a nice flashlight that made a pretty tight beam and was the right size.  No dark spots here Every part of the reflector shows the die. With this setup and a blade with 6 feet of gift wrap butted up against the reflector it is a close 2nd behind a good lens setup.






Here is the same led with a good lens but poorly positioned. You can see a big ring around the center.





Here is a lens that I took out of a head mounted lamp. It is a good fit for the led and positioned well. No dead spots.





And the same from a bit to the side. You can still see a little of the die from the side but its almost gone. Not as narrow as the 8 degree but better than the reflector.




The SSR90 is the only led I have both a good reflector and lens for so this is the best comparison I can make. Here is the same lens as above but mounted in a blade holder shown on a wall. It is not super narrow, probably about 15 degrees.




Here is the reflector mounted in a blade holder shown against the wall. It does produce a good fairly tight spot. The down side is all the light not going in the right direction that appears as the big ring around the outside.




Here are the last two together. Showing the major differences. The green one with the reflector has a less even center with some hot spots. The blue with lens is more even. When light intensity is measured with a light meter. The hot spots are a ring around the center as strong as the lens center witch can work to our advantage. But the lens covers more area with high readings. I would guess the reflector is losing about 10% of the light to the side.








Conclusion:

Due to our space constraints a lens has the potential to work better than a reflector. Like with the rebel the Carclo 8.7 degree is hard to beat. But it is very hard to find lenses or reflectors that can work good for many leds. So whatever fits best (less visible dead spots and more die) is best.  Basically ether can work good if they fit the led well, have a smooth surface that transferís light well, and the light is dumped directly into gift wrap forcing it down the blade. And if you like more flair at the bottom of  the blade there are more parts available to use or find.


So for those who have eliminated those dead spots please add the details of your solution to this thread with a picture if possible. Or if you can add more detailed information even better.



Offline Artorius Vidnyl

  • Force User
  • ***
  • Posts: 192
  • Suns of the Force
Re: A Light Focusing Solution Thread
« Reply #1 on: July 20, 2011, 05:21:27 PM »
Thank you for posting this!  My friend and I are preparing to do our first build and I'm going to print this out so we can reference it.  Again thank you!

"Always remember, your focus determines your reality."
―Qui-Gon

Offline Ultra

  • Master Force User
  • *****
  • Posts: 2037
Re: A Light Focusing Solution Thread
« Reply #2 on: July 22, 2011, 09:57:43 AM »
Differences in actual blade illumination would be better illustrated with side by side blade comparisons using the different focusing solutions you are trying to test.

Very few smiths actually have extended experience with reflectors.  The MHS was built to use the LXHL-NX05 collimator lens, so even if reflectors were better, few could even try them since they would not fit in an MHS saber.  I went to great expense to develop a module that would get around this limitation and allow me to use the more expensive reflectors in MHS compatible sabers.  Needless to say, I would not have bothered if I did not feel there was a true benefit to the additional cost of reflectors over optics in my sabers.

So what about modern times?  Have optics gotten better?  In a word, no.

The light transmission efficiency of lenses has not improved in recent years, it's actually gone down.  The desire for lens makers to make a lens capable of withstanding the incredible heat produced by modern LED's has forced them to move away from PMMA optical acrylic to a less efficient medium.

The Carclo 8.7į lens has an 86% light transmission efficiency. 

On a Rebel, that is.  It has only a 79% light transmission efficiency on a Seoul P4.

It is made from polycarbonate, the same kind they make eye glass lenses from, which is one reason why the efficiency is so low.  It can withstand higher heat than acrylic, but at a cost to visual acuity.

Visual acuity aside, polycarbonate is "soft", which is why it makes a great blade, but lenses made from Polycarb scratch easily and exhibit aberattions.  That is why Carclo even states in it's datasheets that visible inclusions (defects you can see with the naked eye) in the lenses are within standards.  From the datasheet:

"Please note that flow lines, weld lines and small black or white inclusions within the lenses are acceptable if the optical performance of the lens is within the specification described to +/-10%."

+/- 10% is a WIDE variance, but typical for Polycarbonate lenses.  How many of you are ok with a variance of 10% for light transmission?

What about the "old" lenses?
The 10 degree LXHL-NX05 lenses that we all kinda "grew up" on, where made from Optical Grade Acrylic (PMMA) and offered a 90% light transmission efficiency rate.  They were, in essence, a "better" lens than the Carclo 8.7.  I don't have any LXHL-NX05's in 10 degree form to test here against comparable LED's, but perhaps someone will help out this thread with that comparison.  Luckily, there are still PMMA lenses available today for Seoul, Cree, and LedEngin.

Why IMS reflectors?
Reflectors in general have a far higher efficiency rate than lenses; the IMS SO20XA's have a 94% light efficiency when used with lambertian LED's.  The efficiency of a reflector is still unmatched by any lens we use for sabers.

Greater than 90 degree?  It's all about the side spill!

When you're using wide angle emitters, like P4's which have a 120 degree viewing angle, you need a very efficient way to harness the side spill.  The difference between 79% and 94% is pretty significant, so reflectors are an obvious choice. 

The image below compares an SO20XA reflector vs a LXHL-NX05.  As you can see, the IMS harnesses the side spill much better.




Benefit of lenses?
They are cheaper.  Significantly cheaper than reflectors.  You can get good quality optics for 62 cents each if you don't buy in quantity, much less of you do.  In certain multi-die LED's, like the Ledengin 10w, lenses actually do work better than the IMS reflector due to the construction of the LED dome.  They might work better for Rebels, but I don't use rebels anymore, so I'm not concerned with that.


3 to 6 times brighter??

Don't believe the hype; using a reflector or a lens will NOT make your saber orders of magnitudes brighter.

Pictures are worth a thousand words, so here's a little evidence in practice.  I sponsor a Lucasfilm approved stage combat team called Defenders of the Force.  They use the sabers I build in their live performances.  Needless to say, in a live performance, sabers need to be durable and bright.  All the sabers shown use reflectors.  The LED's used are Luxeon III for the reds, Seoul P4 for green and blue, RGB for Arctic Blue and SRD.  Bright enough?  They think so.  You be the judge:

Some daylight photos:











And of course, they look pretty nice at night, too  :D:




So where do we go from here?
Moving forward is always the goal, and the path forward lies not in choosing one technology over the other, but rather combining the benefits of both technologies.  Yoda and I are in preliminary tests of a new reflector+lens holder based on my machined aluminum reflector unit I debuted in this video:

http://www.youtube.com/watch?v=gmfcUECOSO4

The idea is to use a specially machined reflector to hold the optic, thus harnessing the side-spill efficiency of the reflector and the collimating of the optic to make a unit superior to either.  Here is the latest prototype:



The new unit does indeed make a fuller blade in every drop-in test I have performed.  Yoda will be conducting his own tests.  The real question is whether or not the benefit is worth the extra cost, and that's why we are continuing to refine and perfect the concept.  Thanks for reading this far.  Sorry to be so verbose, but this subject is alot more nuanced and complex than most are aware.

Reason for Edit: Added Quote for Pertinent information pertaining to topic.
« Last Edit: August 20, 2011, 05:08:42 PM by Yoda »

Offline RedArc

  • Experienced Force User
  • ****
  • Posts: 460
Re: A Light Focusing Solution Thread
« Reply #3 on: July 22, 2011, 10:29:18 AM »
Very interesting !

Thanks mate  ;)



Offline Sunrider

  • Unlimited Brightness!!! RRROOAARRR!!!
  • Master Force User
  • *****
  • Posts: 585
Re: A Light Focusing Solution Thread
« Reply #4 on: July 22, 2011, 02:35:00 PM »
Differences in actual blade illumination would be better illustrated with side by side blade comparisons using the different focusing solutions you are trying to test.

That info would also be useful. But the major point I tried to make was that you can to a good degree, predict what a focuser will do by looking at it mounted. A blade is somewhat secondary if it has several feet of gift wrap. From my testing, as long as the focuser is highly efficient you will have a hard time seeing a difference between two of the same blade.

I am not in a position to put together all those comparisons as I don't have 2 of enough parts to do it. Maybe you are? It would help others out if people with the means could add what info they can here.   ;)



Very interesting !

Thanks mate  ;)

 You are welcome Sir.  :)

Offline cannibal869

  • I dub thee Darth..........Lecter.
  • Master Force User
  • *****
  • Posts: 795
  • NUCLEAR POWERED JEDI at work!!!
Re: A Light Focusing Solution Thread
« Reply #5 on: July 22, 2011, 03:48:59 PM »
might I suggest a sticky mods?

thanks man this is awesome info.  I may have a few additional pics soon to send your way ;)

Offline darth_call

  • Master Force User
  • *****
  • Posts: 6841
Re: A Light Focusing Solution Thread
« Reply #6 on: July 22, 2011, 03:50:57 PM »
might I suggest a sticky mods?

The entire mod staff is teflon coated, it's a requirement.
But we'll sticky this topic.


Well done on the subject matter sunrider. A definite good read and something to add to my bookmarked topics.

Offline Sunrider

  • Unlimited Brightness!!! RRROOAARRR!!!
  • Master Force User
  • *****
  • Posts: 585
Re: A Light Focusing Solution Thread
« Reply #7 on: July 22, 2011, 06:08:25 PM »
might I suggest a sticky mods?

thanks man this is awesome info.  I may have a few additional pics soon to send your way ;)

 You're welcome Sir, and by all means add what you can.

might I suggest a sticky mods?

The entire mod staff is teflon coated, it's a requirement.
But we'll sticky this topic.


Well done on the subject matter sunrider. A definite good read and something to add to my bookmarked topics.

 Thank you Lord Vader, I am pleased to do my part for the Empire.  :D

Offline IndustrialAction

  • Master Force User
  • *****
  • Posts: 1870
  • IAC - Elegant designs with a more civilized edge
    • IndustrialAction Customs
Re: A Light Focusing Solution Thread
« Reply #8 on: July 22, 2011, 06:17:13 PM »
Has anyone tried using an adjustable focus lens from a flashlight? There are several different types. I may pick up a few to test out unless someone else has already done it.

Offline Sunrider

  • Unlimited Brightness!!! RRROOAARRR!!!
  • Master Force User
  • *****
  • Posts: 585
Re: A Light Focusing Solution Thread
« Reply #9 on: July 22, 2011, 07:38:13 PM »
 That's where I found the lenses I use for the SSR90, in a head lamp that could make a tight beam with a decent size led. H7 model.

Offline forcejunkie530

  • Experienced Force User
  • ****
  • Posts: 348
Re: A Light Focusing Solution Thread
« Reply #10 on: July 22, 2011, 08:21:41 PM »
If I'm repeating anything that this thread is already talking about I do apologize....but are we talking about making those circles on the wall smaller? That would make for an Insanely bright blade if the light was directed to be a 1 inch diameter if it was shined within 5 to 10 feet from the wall???
My Sabers
1.
2. Ultrasabers Steel Stunt Lux lll Amber
3. Ultrasabers Steel Stunt Lux lll Red
4.. My Custom Makototsai MK-F Series with Cyan added (coming next week!)

Offline Sunrider

  • Unlimited Brightness!!! RRROOAARRR!!!
  • Master Force User
  • *****
  • Posts: 585
Re: A Light Focusing Solution Thread
« Reply #11 on: July 22, 2011, 09:14:31 PM »
The smaller the dot on the wall means a lower degree pattern which is good. Unfortunately lambertian leds cannot be focused much below 10 degrees. And the bigger the die the bigger the focuser must be to keep the tight beam.  ;)

Offline MACE WINDU

  • Formerly known as Nightstorm
  • JEDI/ALLIANCE Master MODERATOR
  • Master Force User
  • **
  • Posts: 1367
  • Do you have a problem with purple?
Re: A Light Focusing Solution Thread
« Reply #12 on: July 22, 2011, 09:42:32 PM »
Thank you for this thread Sunrider.  Very informitive.  It also gave me an idea that I used to fix up a saber I was having troubles with! :)


Offline forcejunkie530

  • Experienced Force User
  • ****
  • Posts: 348
Re: A Light Focusing Solution Thread
« Reply #13 on: July 23, 2011, 01:11:05 AM »
maybe construct it to where you use one full 5 degree lens in its normal position, with another one on top of it upside down? Work with the optics that way...I dunno...just tossing out guesses that might be worth a try
My Sabers
1.
2. Ultrasabers Steel Stunt Lux lll Amber
3. Ultrasabers Steel Stunt Lux lll Red
4.. My Custom Makototsai MK-F Series with Cyan added (coming next week!)

Offline JANGO FETT

  • Owner of Kilsythe Customs
  • Administrator
  • Master Force User
  • *
  • Posts: 9647
    • Youtube channel
Re: A Light Focusing Solution Thread
« Reply #14 on: July 24, 2011, 10:25:20 AM »
reopened.
I'll merge posts back in after going thru them, later.
Reposting or starting another argument will result in a vacation FOR ALL INVOLVED.



Have you heard the tragedy of Mark Hamill the Wise?

My thoughts and prayers to the padawans of Coruscant - Master Jeselnik