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Author Topic: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades  (Read 11164 times)

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Offline Photonic Bladesmith

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Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades - Part 1 LED Tests

After posting the build and test log of Luminous Devices CBT-120 LED based 30 Amp LED sabers driving fluorescent saber blades, [ 30 Amp LED Sabers & Fluorescence Enhanced Saber Blades (Part 1 - Saber) ], LUMINARA of Vader's Vault suggested that I look into CREE XP-E2 LED star arrays as a more electrically efficient and more cost effective source of high output saber blade illumination.  Following up on her advice, I made some purchases and started some tests ...

Custom 3-Up Cree High Power LED




I purchased some Tri-CREE XP-E2 Green and Royal Blue Stars with the intent of testing them to measure the optical output vs. drive current, and the maximum sustained current before LED failure.   The Tri-green CREE XP-E2 LED star was selected because it is rated as the brightest conventional LED source used in current sabers.  The royal blue CREE-XP-E2 LED was selected for testing due to its high absolute optical power in the pumping absorption band for exciting fluorescent saber blades intended for outdoor daylight use.




Two custom Quad-CREE-XP-E2 royal blue LED stars with matching collimating lensed reflectors were ordered from LED Supply [ LEDSupply - For All Your LED Project Needs! ] to be used in constructing a test saber after measurements were made to determine the optimal drive current for this LED.

Cree XPE - QuadPod 4-Up Royal-Blue High Power LED
(Request a custom order Quad Star with Royal Blue CREE XP-E2 LEDs)

An extra Tri-CREE XP-E2 green LED with matching collimating lensed reflectors was set aside from the destructive high current testing to be used to construct a high brightness standard lighting technique saber to be used as a brightness reference to compare to the green fluorescent blade sabers to in different lighting conditions.  A Vader's Vault dual diffused blade was purchased to ensure that a proven design for an efficient bright blade is used for the comparison tests.

The LED stars were attached to 1" diameter copper or aluminum rod stock heat sinks using Arctic Silver thermal conductive epoxy. 



LED output power is measured using Ophir thermal absorption based power measurement heads. Separate DVMs are used to simultaneously measure the drive current and LED voltage drop.  This combined data can be used to measure the efficiency of the LED at a given current in converting electrical input power into optical output power.

OEM thermal and photodiode sensors | OEM Power Sensors - Ophir

______________

Measurements were taken at 0.1 amp increments.  The power was applied to the diode at the measurement current at each step for the ten seconds required to record the, power and LED voltage , and was then turned off to allow the LED to cool back to ambient temperature.

The graph data was recorded using the Tri-CREE XP-E2 stars powering up each diode individually.



Results Summary:

The XP-E2 LEDs are rated by Cree for operation at 1 amp.  At least for short intervals, they can be operated at significantly higher currents, though the increase in brightness with increases in current becomes incrementally smaller at higher current levels.  Past 1.9 amps, increasing the drive current produced no increase in brightness for the green XP-E2 LEDs.

The royal blue XP-E2 LED is about three times more efficient than the XP-E2 green LED in converting electrical input into optical output power.  However, the eye is about twenty times less sensitive in the deep blue than in the green, so a  green LED illuminated blade saber at the same current will still appear over six times as bright ( = six times the lumen rating) as a royal blue LED illuminated conventional saber blade. 

The royal blue CREE XP-E2 LED if used as an optical pump source for a green fluorescent saber blade will have its blue photons transformed into green photons at a 92% efficiency making a fluorescence based green blade three times brighter than an XP-E2 green LED illuminated saber at the same current. 

Used outdoors in daylight, the fluorescent green blade will transform sunlight shining on the blade into even more  green photons making it appear even brighter than a comparably driven green LED conventional blade saber. 

In contrast, conventional diffused clear non-fluorescent blades will interact with sunlight to only wash out the LED color with scattered and reflected white sunlight.

________________

What is the maximum safe operating current?


Sustained operation tests were performed on heat sink mounted XP-E2 green and royal blue LED stars at 1.5 amps and 2.0 amps with the collimator lenses attached and all LEDs operating simultaneously.

At 1.5 amps, the LEDs operated continuously for over an hour with no problems.

At 2.0 amps, the LEDs in the LED stars started to fail and go dead in less than 5 minutes.

The operating current for the new test sabers was selected to be 1.5 amps per LED.

The small incremental increase in brightness going from 1.5 amps to 2.0 amps makes it not worth the effort and cost in LEDs to try to find a possible safe drive level between 1.5 amps and 2.0 amps to drive the LEDs.

_______________

Next: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades - Part 2 Sabers

« Last Edit: June 24, 2017, 07:11:04 PM by Photonic Bladesmith »

Offline Photonic Bladesmith

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Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades - Part 2 Sabers


Two sabers are to be constructed:

Saber  1 - Quad royal blue CREE XP-E2 LED star driven at 1.5 amps per LED - Intended to drive a green fluorescent saber blade at more practical current levels and heat loads than the 30 amp saber referenced in: [http://www.fx-sabers.com/forum/index.php?topic=46064.0]

Saber  2 - Tri green CREE XP-E2 LED star driven at 1.5 amps per LED - Intended to drive a Vader's Vault double diffused saber blade to act as a brightness reference to compare fluorescent blade sabers with a known high brightness rated conventional blade-LED combo.


Sound card - Plecter Labs Nano Biscotte V2.  The Nano Biscotte board is powered by a voltage regulated 5 volts from a lithium battery stack regulated down from 8 volts using a LT3083 programmable voltage/current regulator IC.

LED Driver - The LED driver is custom designed using Linear Technologies LT3083 programmable low dropout voltage linear current/voltage regulator ICs to individually drive each LED on the CREE LED stars.  The four regulators are configured to be switched on and off simultaneously by the Nano Biscotte LED output pad.   Each regulator can be independently set for up to 3 amps output current.  If you want to drive an SSR-90 type high current single die LED, the regulators can be operated in parallel to sum their current outputs into a single LED.



Saber electronics schematic

Power - The saber is powered by a pair of LG brand high current (up to 35 amps) lithium rechargeable 18650 batteries.  A thin wall Kevlar-epoxy tube with spring loaded solid copper rod end contacts holds the batteries and allows them to be rapidly swapped out without tools.

In Stock genuine high discharge rate rechargeable cylindrical 18650 Li-Ion

_______________

Build log:





















_______________
_______________

Measured power and equivalent lumens


Ophir model L150C-A    optical power measurement head

Tri CREE XP-E2 green LED saber at 4.5 amps (1.5 amps per LED)

1.2 watts optical output power at 520 nm
Electric input to optical output efficiency = 8%
Driving a conventional saber blade = 610 lumens



_______


Quad CREE XP-E2 royal blue LED saber at 6 amps (1.5 amps per LED)

5.0 watts optical output power at 450 nm
Electric input to optical output efficiency = 26%
Driving a conventional saber blade = 130 lumens
Driving a green fluorescent saber blade = 2,200 lumens



_______



Luminous Devices CBT-120 Blue LED driven at 30 amps (50% duty cycle square wave drive, 20 Hz)

Link:  30 Amp LED Sabers & Fluorescence Enhanced Saber Blades (Part 1 - Saber)



7.5 watts average / 15 watts peak power    optical output at 462 nm
Electric input to optical output efficiency = 11%

Average power:
Driving a conventional saber blade = 340 lumens
Driving a green fluorescent saber blade = 3,300 lumens

Peak power:
Driving a conventional saber blade = 680 lumens
Driving a green fluorescent saber blade = 6,700 lumens

______________
______________

Outdoor tests:

________

Sabers:

Tri-CREE XP-E2 green LED Saber driven at 4.5 amps- Vader's Vault Double Diffused Blade

Quad-CREE XP-E2 royal blue Saber driven at 6 amps - Fluorescent blade

Luminous Devices blue CBT-120 LED Saber driven at 30 amps (50% duty cycle, square wave) - Fluorescent blade

________

Estimated fluorescent blade luminosity due to sunlight:

Assume that 1/3 of the solar spectrum is in the fluorescein dye excitation band.
Solar Insolation (late afternoon cloudy day and clear day just before sunset) ~ 100-200 watt / square meter
Fluorescein dye pump band to green light conversion efficiency 92%

Photo conditions:
- cloudy day, late afternoon
- clear day, 1 hour before sunset



Starting fluorescent blade brightness in the green from sunlight alone approximately 400 - 800 lumens.
Blue LED illumination fluorescing the blade adds to this baseline brightness value.

Scattered white light from conventional blade approximately 200 - 500 lumens.
This is the white light level that is competing with the LED to wash out the LED color in conventional blades.

__________

Outdoors, cloudy day, late afternoon.



__________

Outdoors, clear day, 1 hour before sunset.






______________
______________

The optical output power of the 6 amp driven royal blue Quad CREE XP-E2 is just slightly less than the time average power output of the 30 amp Luminous devices CBT-120 LED that has been shown to be able to burn blade diameter holes in trash bags. 

A burning capabilities ( and eye hazard ) test is in order for the 6 amp Quad CREE XP-E2 royal blue saber.

The test material here is an 1/8" thick Depron model aircraft foam sheet.

 






Definitely not something that you want to shine into someone's eyes!

____________

Summary:

The Quad CREE XP-E2 royal blue LED is surprisingly efficient in converting electrical input power into optical output.  The CREE XP-E2 royal blue LED has a measured electrical power to optical power conversion efficiency of 26% at 1.5 amps, and 35% at its officially rated drive limit at 1.0 amp.  For driving fluorescent blades, this makes the Quad CREE XP-E2 royal blue LED two and a half times more efficient at converting electrical energy into pump band optical energy than the 30 amp Luminous Devices CBT-120 blue LED which still has the edge for absolute brightness, though at 5 times the drive current.

For making a maximally bright saber blade at a given (reasonable) drive current, a Fluorescein ("day glow green") dyed fluorescent blade, illuminated by an overdriven CREE XP-E2 royal blue LED array seems to be the best option with current technology LEDs (August 2015).   The CREE XP-E2 royal blue driven fluorescent blade has triple the brightness of a conventional blade illuminated by the same generation green LEDs.

So far, both the green and the royal blue CREE XP-E2 LED stars are surviving being driven at 1.5 amps per diode.

Fluorescent blades illuminated by over driven Quad CREE XP-E2 royal blue LEDs are adequately bright for non-direct sunlight outdoor daylight conditions for doing illuminated “glow stick” saber demos.  They are significantly brighter under these conditions than conventional LED in-hilt sabers.  Fluorescent blades have the additional advantage in the a large fraction of the sunlight shining on the blade is converted into the same colored blade light that the LEDs are driving the blade to produce. 

While not having the peak brightness capability of the Luminous Devices blue CBT-120 LEDs, the Quad royal blue CREE stars have the advantages of two to three times higher electrical power to optical output conversion efficiencies resulting in far more reasonable drive current requirements, and a much smaller mechanical form factor enabling them to fit into vastly more hilt designs.

Until a source of fluorescent dyed polycarbonate blades are found, the current acrylic fluorescent dyed saber blades are display/demo only blades not suitable for full speed sparring.


Thanks again to LUMINARA for the suggestion to investigate the use of CREE XP-E2 LEDs for my high brightness saber blade experiments.






« Last Edit: June 24, 2017, 07:13:47 PM by Photonic Bladesmith »

Offline Greywolf

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Wow, so much fascinating information ^-^ ...

Thank you very much for sharing!
Life is but a series of missed opportunities.

Offline Askew Wai

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This is great to know, particularly seeing testing of the upper amp limits of the LEDs.

Since you have the green tri-Cree and the flourescent blade, can you also consider that combination? Accepting there may be no flourescence of the LED light, but flourescence of daylight plus transmitted green LED glow might still be a match for blue->flourescence (or else emphasise the gains resulting from blue LEDs).

Offline LUMINARA UNDULI

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Photonic Bladesmith, your work is inspiring!  Thank you so much for sharing this awesome new tech with the community and your continued research :).

You have a PM my friend :D.



Website: Vader's vault
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Offline ShadyCanuck

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For making a maximally bright saber blade at a given (reasonable) drive current, a Fluorescein ("day glow green") dyed fluorescent blade, illuminated by an overdriven CREE XP-E2 royal blue LED array seems to be the best option with current technology LEDs (August 2015).   The CREE XP-E2 royal blue driven fluorescent blade has triple the brightness of a conventional blade illuminated by the same generation green LEDs.

So far, both the green and the royal blue CREE XP-E2 LED stars are surviving being driven at 1.5 amps per diode.

Fluorescent blades illuminated by over driven Quad CREE XP-E2 royal blue LEDs are adequately bright for non-direct sunlight outdoor daylight conditions for doing illuminated “glow stick” saber demos.  They are significantly brighter under these conditions than conventional LED in-hilt sabers.  Fluorescent blades have the additional advantage in the a large fraction of the sunlight shining on the blade is converted into the same colored blade light that the LEDs are driving the blade to produce. 

While not having the peak brightness capability of the Luminous Devices blue CBT-120 LEDs, the Quad royal blue CREE stars have the advantages of two to three times higher electrical power to optical output conversion efficiencies resulting in far more reasonable drive current requirements, and a much smaller mechanical form factor enabling them to fit into vastly more hilt designs.

Until a source of fluorescent dyed polycarbonate blades are found, the current acrylic fluorescent dyed saber blades are display/demo only blades not suitable for full speed sparring.


Thanks again to LUMINARA for the suggestion to investigate the use of CREE XP-E2 LEDs for my high brightness saber blade experiments.

Fantastic work and research. My hat is off to you, sir!

Now down to business: someone needs to start producing fluorescent dyed polycarbonate blades so we can actually duel with them.  But I would settle for even just one these current acrylic fluorescent dyed saber blades for display/demo use. 

Anyone?  Anyone at all?!?
Do or do not. There is no try.

Offline STARKILLER

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ShadyCanuck, ask and ye shall receive  ;D

We just got the first shipment in: The Vader's Vault Photon Blade will launch in the store very soon. Tested the first one tonight and it's amazing.


Offline Wilbur

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ShadyCanuck, ask and ye shall receive  ;D

We just got the first shipment in: The Vader's Vault Photon Blade will launch in the store very soon. Tested the first one tonight and it's amazing.

This has me so excited!   :D

Offline ShadyCanuck

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ShadyCanuck, ask and ye shall receive  ;D

We just got the first shipment in: The Vader's Vault Photon Blade will launch in the store very soon. Tested the first one tonight and it's amazing.

That. Is. AWESOME!
Do or do not. There is no try.

Offline Sethski

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Photonic Bladesmith - thank you so much for all the work you've put in to this and for sharing in such detail - really interesting, really exciting! - and double excited with Vader's Vault's 'Photon' polycarbonate blades  8)

I'm curious too - do you think royal blue frequency LEDs in a string blade set up with a flourescent blade could work to give a similar boost in brightness?   

Offline LUMINARA UNDULI

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Re: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades
« Reply #10 on: August 23, 2015, 05:35:56 AM »
Sethski, we are working on that right now with the Photon™ blade.  I should have results for you in the coming weeks as to how that works.  With our testing, I am extremely optimistic, but until we have the actual empirical data that's the best I can say.



Website: Vader's vault
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Offline Sethski

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Re: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades
« Reply #11 on: August 23, 2015, 08:03:57 AM »
Sethski, we are working on that right now with the Photon™ blade.  I should have results for you in the coming weeks as to how that works.  With our testing, I am extremely optimistic, but until we have the actual empirical data that's the best I can say.

That's awesome!  :D Look forward to seeing how it works and hoping it works well.

Are you going to try a few different LEDs for test string segments or something like that?

It'd be great to know which LEDS you use and find best if you're happy to share that.

I was looking on Mouser and bookmarked these two on basis of mix of price/angle/luminosity/wavelength (from brief reading - so may be wrong - it looks like the optimum wavelength for excitation of the fluorescin is 490nm?):
VAOL-5GSBY4 VCC | Mouser
C503B-BCN-CV0Z0461 Cree, Inc. | Mouser

Offline ShadyCanuck

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Re: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades
« Reply #12 on: August 23, 2015, 01:51:59 PM »

Custom 3-Up Cree High Power LED




I purchased some Tri-CREE XP-E2 Green and Royal Blue Stars with the intent of testing them to measure the optical output vs. drive current, and the maximum sustained current before LED failure.   The Tri-green CREE XP-E2 LED star was selected because it is rated as the brightest conventional LED source used in current sabers.  The royal blue CREE-XP-E2 LED was selected for testing due to its high absolute optical power in the pumping absorption band for exciting fluorescent saber blades intended for outdoor daylight use.




Two custom Quad-CREE-XP-E2 royal blue LED stars with matching collimating lensed reflectors were ordered from LED Supply [ LEDSupply - For All Your LED Project Needs! ] to be used in constructing a test saber after measurements were made to determine the optimal drive current for this LED.

Cree XPE - QuadPod 4-Up Royal-Blue High Power LED


........

The royal blue XP-E2 LED is about three times more efficient than the XP-E2 green LED in converting electrical input into optical output power.  However, the eye is about twenty times less sensitive in the deep blue than in the green, so a  green LED illuminated blade saber at the same current will still appear over six times as bright ( = six times the lumen rating) as a royal blue LED illuminated conventional saber blade. 

The royal blue CREE XP-E2 LED if used as an optical pump source for a green fluorescent saber blade will have its blue photons transformed into green photons at a 92% efficiency making a fluorescence based green blade three times brighter than an XP-E2 green LED illuminated saber at the same current. 



The link you posted here for the quad cree blue LED is for Quad XPE - not a Quad XP-E2 configuration.  I thought the XP-E2 was the second generation of the XPE LED.  Am I wrong?  And does the XP-E2 even come as Quad-Cree, or only as a Tri-Cree?  I'm just trying to get my head around this stuff...
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Offline Photonic Bladesmith

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Re: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades
« Reply #13 on: August 23, 2015, 03:16:35 PM »

Custom 3-Up Cree High Power LED




I purchased some Tri-CREE XP-E2 Green and Royal Blue Stars with the intent of testing them to measure the optical output vs. drive current, and the maximum sustained current before LED failure.   The Tri-green CREE XP-E2 LED star was selected because it is rated as the brightest conventional LED source used in current sabers.  The royal blue CREE-XP-E2 LED was selected for testing due to its high absolute optical power in the pumping absorption band for exciting fluorescent saber blades intended for outdoor daylight use.




Two custom Quad-CREE-XP-E2 royal blue LED stars with matching collimating lensed reflectors were ordered from LED Supply [ LEDSupply - For All Your LED Project Needs! ] to be used in constructing a test saber after measurements were made to determine the optimal drive current for this LED.

Cree XPE - QuadPod 4-Up Royal-Blue High Power LED


........

The royal blue XP-E2 LED is about three times more efficient than the XP-E2 green LED in converting electrical input into optical output power.  However, the eye is about twenty times less sensitive in the deep blue than in the green, so a  green LED illuminated blade saber at the same current will still appear over six times as bright ( = six times the lumen rating) as a royal blue LED illuminated conventional saber blade. 

The royal blue CREE XP-E2 LED if used as an optical pump source for a green fluorescent saber blade will have its blue photons transformed into green photons at a 92% efficiency making a fluorescence based green blade three times brighter than an XP-E2 green LED illuminated saber at the same current. 



The link you posted here for the quad cree blue LED is for Quad XPE - not a Quad XP-E2 configuration.  I thought the XP-E2 was the second generation of the XPE LED.  Am I wrong?  And does the XP-E2 even come as Quad-Cree, or only as a Tri-Cree?  I'm just trying to get my head around this stuff...

I emailed LED Supply and asked them if they can make me the Quad star with XP-E2 Royal Blue LEDs and they said that they would as a special order.
I added a correction to my original post to specify that the Quad Royal Blue CREE XP-E2 LED star was a special order item.

My tests were performed with the special order Quad CREE XP-E2 LED Stars that they made for me.

(What I would really like is to have the connections that Vader's Vault have and  be able to get CREE XP-E2 LED stars made with the latest select high output binned LEDs!)


Below is what LED Supply sent me when I requested a special order for Royal Blue  Quad CREE XP-E2 LED stars:

__________

LED Supply Sales Team <sales@ledsupply.com> 

Mar 26

 We can build the QuadPod LED with the Royal-Blue Cree XP-E2 LED.  The price for the QuadPod with the XP-E2 LED would be the same as the Deep-Red version.  To place your order through the website, order 3 of this item (Luxeon Rebel - QuadPod 4-Up Deep-Red High Power LED).  Then leave us a note in the "Comments" field during checkout that you want the QuadPod made with the Royal-Blue XP-E2 LED.  The lead time for this order would be 7-10 business days.

 Respectfully,

 --
 David McGalliard | LEDSupply Sales Manager
802.728.6031
LEDSupply - For All Your LED Project Needs!
LEDSupply - YouTube
http://www.facebook.com/ledsupply

« Last Edit: August 23, 2015, 03:27:27 PM by Photonic Bladesmith »

Offline LUMINARA UNDULI

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Re: Overdriven CREE XP-E2 LED Sabers & Fluorescence Enhanced Saber Blades
« Reply #14 on: August 23, 2015, 06:04:07 PM »
Photonic, we can help you in the LED department.  We can chat via PM :).



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