Umm, because they’re “total internal reflection” lenses? :laughing:
Seriously, it’d be hard to bulk AR-coat just the front surface and mask the rest of the lens. AR-coating the sides/back would be like poking holes in a bucket…
With reflectors, a lot of front-firing light just shoots out all over the place as spill, not really contributing to usable light.
With a TIR lens, almost all of the light is captured, and ideally would be focused to the hotspot with little wasted spill. The only problem (that depends on the type/shape/size of the LED) is that light at the extremes, eg, the corners of the chip, is sufficiently off-center that it might not hit at the critical angle or less, so ends up escaping vs being reflected back into the lens and directed out front.
A perfectly point-source LED chip would get close to “100%” efficiency, minus losses passing through the medium.
Nope, AR coating doesn’t change refraction angle. And so it doesn’t change the total internal reflection angle.
It just adds a layer (or several) with refraction index between that of air and of glass.
What happens with light that tries to escape glass at angle that would reflect off air when it hits AR coating layer instead?
2 cases:
either the angle is so high that it reflects anyway (but an angle that’s different from the one of uncoated)
or not, it just refracts
In the second case, the light hits air at much steeper angle and reflects. Then hits glass and refracts. Overall it travels at the same angle as if there would be no coating, but is shifted slightly.
I get what you’re saying, but something I remember reading a while ago about coatings on camera-lens glass, why some pieces are coated and others aren’t, seemed to imply that the coating did change the angle.
I found my measurement results. Indeed, with 21 mm TIR luminous flux falls relative to the reflector. probably due to the fact that part of the lens is overlapped by the edge of the bezel.
My numbers (these are not lumens, my sphere is not calibrated!)
17 mm TIR with glass - 412
Reflector with glass - 399
Reflector with glass ang 3M Magic scotch - 381
21 мм TIR without glass - 346
TIR lenses are not all the same. Some are narrow focus and clear and might have less losses than a reflector. Some are wide focus and might be frosted or textured and have more losses than a reflector.
For my head mounted lights, I use this 60° textured lens.
I do get some losses, but it’s no big deal. All my headlights are more than bright enough to compensate since they are for close up work anyway.
On this particular test I think I estimated the output drop using a different light.
So just to make sure I use the same headlamp and battery and then switch out the 60° TIR (including factory lens) with the original reflector I tested it again.
I also used my TA Tube lumen tester with a .65 .68 correction factor (this should be the correct one). I also used a fresh off the charger 30Q battery.
With reflector - 689 720 lumen
With TIR lens - 526 550 lumen
So we have a loss of 23.6% in output
I did the same measurements using two Eagle Eye X2R and got slightly less drops in output by switching to the 60 degree TIR lens. One light measured 18.5% and the other 20%.
All of these lights use the factory glass lens so the only thing that changed was the reflector for a plastic TIR optic.
Just got mine last night and am very happy with it. But it was so cheap so I thought I would try another one.
I like the style of the Skilhunt headlamp so I threw the similar looking Boruit EFL0867 in the cart. I will probably get some use out of it especially since my wife asked if she good keep the EHL0628 on her nightstand. I should of got 2 EHL0628’s. I also shoud have paid more attention to the modes, High/Middle/Strobe. This is what I saw…Switch Mode:High/Middle/Low. It is uncomfortable to read with and would destroy your night vision while camping. In conclusion I would recommend avoiding this one:
I see it spending most of its life in a drawer. If only it had Narsil UI it would be my new edc just be wearing a headlight at all times everywhere
edit-should have, not should of
s.-Sorry if I am way off the thread topic but I wanted to add I’ve been playing with
ELF0867. About 6 fast clicks from off turns it into a one function light just Med. Which
makes it more usable IMHO
ps. 3rd time is a charm right? Again sorry for being off topic, but I have to correct what
I previously said. 6 fast clicks puts the light in a weird mode. One click lights the red
switch only. 2nd click puts it in weird dim-brighten-dim-brighten…Is my battery failing?
What the hell mode.
I have 6 different types of diffuser film I’m selling these days and none of them plays well with this reflector .maybe it’s the emitter /reflector combo IDK .As a mule Dc-Fix works fine just not with the reflector .
iIm going to drop in a Samsung h351D anyway so i’ll let you know if it’s the reflector or the emitter .
I bought this light thinking it was a stepless ramping like the boruit R2 has with no PWM .
It’s NOT a smooth stepless ramping light . It JUMPS thru modes when you hold the button down . Chinese descriptions are never very helpful and like garrybunk says . the User interface is a bit hard to describe . it’s really rather simple and it doesn’t deserve all the stupid hate it received from members here on this thread (all of which don’t own the light ) user interface isn’t a smooth ramp and …doesn’t suck .
I love the light and think besides the Skillhunt H03 this is one of the best cheap headlamps out there .
I had ordered 2 and have been using one at work with great success. Don’t mind the stock emitter’s tint because my whole shop is coated in oil and coolant so it just makes it pretty.
The one I keep at home finally got an emitter upgrade with an XM-L2 U3 3D on Noctigon 20mm. Replaced the 2 wires to MCPCB with teflon coated.
Note: the solder points on the switch side of the board need to be trimmed very close to the board or they will short out against the button retaining ring when you screw it together.
It’s anodized, but why risk it? You can test by simply placing the retaining ring against the assembly and verify that they aren’t dragging on it.
Using it for night fishing, very comfortable light. No cons, except emitter. It must be swapped with warmer, stock cool white is not suitable in foggy weather.
Wildcat, thanks for the Convoy tip!
My Convoy optics arrived and after testing I decided it must be permanent.
After sanding the sides of the optic I also wallowed out the inside of the bezel to allow the shoulder of the optic to rest on it.
Bonus was that there is a groove on the inside of the bezel that I was able to slip the o-ring into to keep the optic in place and give it some water resistance.
Didn’t need to adjust the height of the optic, sits just perfect and has a little downward pressure on the MCPCB. I left the reflector centering guide in.
The beam is much more usable for closer work and there are no sharp demarcations between hotspot and spill, or any rings around the outer edge.
Pictures can explain better than me:
I had a 219C 5000K laying around from another light, on a 16mm mcpcb, so I swapped it in like you. I only needed to extend one wire. It works and looks great under a 60° TIR lens.
Output on high went down from 495 lm to 330 lm. (Maukka calibrated TA Lumen Tube) I’ve got more than enough brightness to handle the close-up type work I use it for such as soldering and automotive repair. It’s the perfect little light now. :+1:
I saw this some time ago and bought one. since, I have bought 3 more. This really is a good headlamp for around $11! I just tried to find a couple more for friends and can hardly find them anywhere.
Does anyone know where to get them other than Aliexpress?
Banggood seems to sell a version of this Boruit EHL0628 but is known as the Xanes D10 headlamp. I haven’t tried ordering from BG so I’m not sure if it’s exactly the same or they just look the same (based on the item description and usage operation and the pictures posted). I got the EHL0628 from their official store in AliExpress.
I finally got around to changing the LED and optics in my EHL0628 (XP-L ON 16mm copper and TIR).
I didn’t want to solder an extension to the wire so I took off the driver and soldered longer wires directly to it. I took the chance to shoot some photos.
Note that this is the old version bought almost a year ago, the new version has a new UI (with stepless dimming).
[Edit: Sorry, no new version and no new UI. I misunderstood the phrase “stepless dimming” (I’m not a native English speaker)]
Charging circuit:
Looks like two TP4057 chips in parallel.
The driver:
A quick guess would be that the unmarked SO-8 IC is an MCU that is providing PWM to switch two transistors (SOT-23-3 chips) through current limiting resistors (the 3 1ohms in parallel).
The two boards are separated by a plastic spacer (sorry about the quality, took this one with my phone’s camera):
