While musing the purchase of a LEP, I’ve not seen the two styles (laser shine through and laser reflected) differentiated much.
Is it worthwhile to differentiate the two? Perhaps as Transmission LEP (TLEP) and Reflected LEP (RLEP)?
I’ve not seen much on pros/cons of each design, I’m worried that either may suffer from rapid phosphor damage over time.
Fair enough..
I just call them shine-through or LEP with mirror :D
But yeah, that might be useful.. If you (or anyone else) have any other suggestions for names, that would be helpful.
Thread for name discussion of the 2 variants here: https://budgetlightforum.com/t/-/69262
So I was about to submit a warranty claim to Fenix for the aforementioned issue, when I began to wonder if I was just being neurotic and this issue was actually a non-issue, or even something that I just never noticed before. I still think this is probably a new issue, but I thought I would offer the light as is here for $140 if anyone wants to buy it, before I go try to go through the warranty process. I will make a sale thread if anyone is interested.
Anybody stumble across this yet? https://www.aliexpress.com/item/1005003814334109.html?
Built in 21700 isn’t my style, nor the power bank functions, but the UI is actually ok with two mode groups… one being single mode - which is what counts in my book.
No, hadn't seen that one before.
I like their use cases!
must be fun meetings!
I don’t like the lack of a cover glass over the projection lens. The projection lens is always plastic in LEPs.
Fair point! I didn't notice that.
btw.. I hadn't seen this *fire name before yet.
I'd love to see manufacturers focus more on features and functionality, instead of just all gunning for the current longest throw title. Maybe a zoomable? Maybe surround it with LEDs like the new Lumintop? How about a better UI...an aduril 2 LEP! I love angle lights/headlights..maybe an angle light LEP?
Hi everyone great thread. What I would like to know is why are the lumens on the LEP’S, so low. The highest I have seen is 900 lumens.
I can’t imagine any use for this but for some reason a LEP headlamp still sounds like a great idea!
The headlamp with the most throw that I know of is the Maxtoch Eagle LR552, which only throws 850m / 180kcd. Imagine a LEP headlamp with about 2km throw!
The Amutorch BT55 is being advertised again. $170 group buy for 2600m throw / 1.7 Mcd!
Hi, I am very interested in the LEP light, but the laser class 3B makes it a little hard to get my hands on. Has anyone close to you had to look directly at the LEP light? Would it be like an accident with a laser pointer?
I’m not willing to try! I only have the TK30 by Fenix from this lineup. It doesn’t seem like a friendly candidate to gaze into.
Does anyone know if all of these LEP flashlights are using the same wavelength laser to excite the phosphor? What do they use? I know a blue wavelength, but blue laser diodes can be purchased fairly inexpensively from 405 to 460 nm.
They will likely all be close to 460nm because that's where the Ce:YAG Phosphor has the highest absorption rate and also where the most powerful laser diodes can be had.
Update:
The NUBM44 450 nm laser diode is the most powerful blue right now I am aware of producing about 8 watts output, there are 465 nm diodes such as the NUBM07E which can produce about 3 watts at 465 nm or so, but not eight watts at that long of a blue wavelength.
Last night I pointed a 410 nm violet-blue 1.5 watt laser pointer at the phosphor of a SBT90.2 LED and the light output from its surface was brilliant white, I tried 450 nm and the output was a dull yellow. Although not sure what phosphor they are using for that diode.
450nm is almost the same as 465nm. In this case only the output of the laser diode really matters. So yes, the NUBM44 is probably the most powerful.
How bright is your 450nm laser? It's very unlikely that the phosphor of the SBT90.2 LEDs does not have it's maximum absorption at 450-465nm.
I have tried this myself with an Osram Black flat here (in German) and a 3W ~445nm diode. The Osram LED became brighter when lit up by the laser even when it was running at full power and the laser was not even perfectly focussed on the LED (no cylindrical correction optics, only a standard "G2" focussing lens).
My available test wavelengths:
I have several blue laser pointers, I'm afraid to use the eight watt one on my flashlight, may damage it. The powers available to me are 200 mw, 1 watt, 3 watts and 8 watts from 405 to 488 nm (450 nm @8W). I tried the 200 mw 450 nm laser and the 1.5 watt 410 nm pointer produced the best result. As a note to your concern about unequal drive powers into the phosphor, I defocused the 410 quite a bit to roughly approximate the power density of the 200 mw pointer and I could clearly see 450 nm was far less effective at producing much output, only seeing some yellow.
Splitting nm hairs:
When I say the wavelengths are far different I'm coming from a visual standpoint. For myself, even 5 nm makes a big difference in how the tint of a beam appears to me. Because our eyes are less and less sensitive to the shorter blue wavelengths, I prefer the longer wavelength blue lasers, so the difference between 450 nm and 460 nm is very substantial to me, but of course the sensitivity of our retina to wavelength isn't what we are discussing.
Back to what I'm looking for:
I'm really curious what wavelength most LEP flashlights are using to excite the phosphor, I have a W3 Pro and a spectrometer good to .2 nm accuracy, time to set it up and try to find the answer for that flashlight. So far, searching Google, I haven't found much information regarding the excitation wavelengths used in LEP's, so far only the mention of blue wavelength which is fairly wide in terms of the blue visual spectrum, in nanometers. However, there are only a few common wavelength of blue laser diodes, such as 445, 450, 460, 465 nm (plus or minus a nm or so), the shorter wavelengths being able to produce substantially greater amounts of coherent light output.
Where to get LEP optimized phosphor for blue pump wavelengths?
Anyone have a recommendation of where I can purchase the phosphor, or the phosphor targets being used in LEP flashlights? Seems they are secret sauce in this industry now, not much can be found, I'm unable to find samples available for the ones used in these flashlights.
I was able to find some phosphor coated disks (with the outer edge in a ring coated, not the centers) used with laser projectors which respond brilliantly to 410 nm. Perhaps I will use those for my home brew LEP flashlight I want to build. I'd like to build one which can produce several times the lumen output of the LEP's available to me in the market right now.