Dosun Solar Headlamp

[half-watt]

1. DoSun's idea may still be patentable - depends upon the "claims" (viz. the proper legal term) that they make. it is not unusual to have a couple of dozen claims in a single patent. an engineer who works for a company might like to break these "claims" out into multiple patents (sometimes successfuly; sometimes not), but often corporate patent counsel will bundle a bunch together, either for legal reasons (to better insure that the patent is granted), or for financial reasons (cheaper to file for one patent than for five patents or two dozen).

2. DoSun's idea may(???) be unique in certain respects - particularly their "eagle" [eye] beam pattern (broad/wide like our eyes are naturally used to seeing in daylight). some headlamps provide this feature as an array of multiple LEDs (think FoxFury here) and as a somewhat fixed output mode (unless lower output levels are used by lighting fewer LEDs, again FoxFury). DoSun uses a single light source and a moveable reflector such that the wide/broad/eagle beam is not mandatory. also, the output level is variable for any of the beam patterns. is this unique? don't know. one would need to do a search of prior art.

3. If the next logical step has NOT been patented, then it may(???) be patented subject to at the very least the following standard caveat (using the actual legalese phraseology which after 25+ yrs as an engineer i've now committed to memory): "the invention must be unobvious to one skilled in the art". the comment on the rotating bezel might(???) be obvious to one skilled in the art of headlamp design, but then it might not be so to the patent examiner and so might be granted (though it could later be challenged in court with outcome uncertain). however, IMO, it would not so much be the concept of the rotating bezel, but rather the overall system operation that might be patentable, i.e. something like "a system using [some "tech" [talk/speak], to use the Hollywood script writing term, here for their particular mechanism/design] which rotates between three areas of a reflector, providing a pure flood output, a unique[??? i'm not sure 'bout this either being unique, but assume for the moment that it is] wide angle field of illumination from a single LED light source, and a near-far dual spot...". something like the idea of a four wheeled vehicle that moves under its own power is a nice concept/idea, but is not patentable in and of itself. patents are intended to provide protection and foster an atmosphere of creativity. such a broad claim of a four wheeled vehicle that moves under its own power (i.e. self-propelled) would stifle creativity and would never be granted, IMO.

4. as far as public knowlegde goes, that would, again, probably depend upon the "claims" made in DoSun's patent. public knowledge and knowledge which the inventor has not kept secret until disclosing and applying for a patent (though the patent may not yet be granted), is not patentable.

5. in the good ol' USofA patents are good for 17y after which others may make use of one's invention without licensing/royalties (this, again, is to foster continual improvement and invention, hence the shorter "protection" of 17y for US patents), though they are in effect longer in some other countries.

i've been amazed at what can get patented. for some decades now with a technology explosion occurring and patent examiners not knowledgeable in some areas of science and technology, sometimes patents are granted which would never even pass the test of "unobvious to one skilled in the art". however, the patent examiner grants the patent since he/she is not skilled in the art and thinks that the invention is pretty neat. among others, there is a famous early software patent granted a number of years ago regarding insuring the visibility of a mouse pointer/cursor regardless of the background color. this patent was granted when, IMO, it never should have been due to the innate/obvious method that was being employed (a programmer would obviously use the XOR [aka "logical difference"] operation to ensure pointer visibility on any background color). an entire US company was formed on the basis of the patent with what appeared to be one sole "raison d'etre" [i.e. "reason for being" - IIRC, this company at the time did not have a marketable product - only an obvious idea for which a patent was, IMO, mistakenly granted], viz. with a legal department that cruised trade shows and conventions looking for POSSIBLE patent "infringement" and then issued letters demanding either cease and desist or licensing royalties, else the inevitable litigation would ensue - both Apple and IBM received "nastygrams" from the legal vultures circling above, or is it the bottom-feeding slugs slithering along??

 

[uk_caver]

The 'flat' beam is somewhat unusual, though noncircular beams from LEDs do seem to be available in various LED optics, so the possibility of doing something similar with a reflector isn't enirely novel.
In fact, if playing with an LED and half a reflector, the possibility (if not the actuality) of all kinds of odd shapes is hard to avoid, though it would presumably take some ability with optics and/or good software to get a nice clean beam pattern of given shape.

I wonder, would some similar effect (spot, diffuse, oval) be possible if using a fixed half-reflector along with a rotating front-glass with a fresnel lens for the oval, as well as a fresnel +/or diffuser film for the diffuse light?

 

[lasercrazy]

So where are the beamshots?

 

[half-watt]

Re: Dosun Solar Headlamp at Fenix-Store.com

i just want to know the lumen rating of them?

all number Mfr. Claimed:

Boost 120% / 104 lm for MOMENTARY use (not sure of continuous TIME allowed)
Hi 100% / 93.6 lm for 3h on alk. (currently testing it with Sanyo 2700 NiMH 02:07 at this time)
Med 60% / 52 lm for 5h
Lo 30% / 20.8 lm for 12h
Slow Strobe (a dbl-flash with a short pause) 100%/Hi for 12h
Fast Strobe (very fast strobe) 100%/Hi for 6h (so, probably a 50% duty cycle or thereabouts since burn-time is 2x constant 100%/Hi burn-time).

i'll try to remember to Post-back the final burn-time on Hi w/the Sanyo 2700 (they came off the charger early yesterday evening and the burn-time test started at 0730 today).

if the burn-time results are similar to another CPF-er's test of the DoSun R1 (a 2xAA flashlight), then the NiMH burn-times in the H1 are expected to be >2x as long as cp. to the alk. burn-times. however, other than the fact that both lights are made by DoSun, there is no other basis on my part for ASSUMING (actually HOPING) that a similar increase in burn-time will occur with the H1 running off of 3xAA NiMH.


EDIT:
at this point in time i still don't have a light meter (logging or otherwise) and am merely timing the burn-time until the light becomes very dim, glows, or shuts off (don't know if direct drive occurs if Vin gets too low to support the regulator/converter electronics).

also, have never owned a camera, so no beamshots from me. beamshots, IMO, would NOT be helpful unless they were pics of actual outdoor use. why? the reflector on the H1 has three distinct areas which are rotated to the bottom of the head, thus placing that portion of the reflector directly UNDER the downward firing LED (the LED has a reflective cylinder all around it, including "out the front", except the part pointing down which allows light to only directly strike the bottom ~120deg of the reflector when the reflector is positioned at any azimuth.

if one is white wall "hunting", the beam is NOT a pretty beam, IMO, when in any of the three positions (i.e. spot, eagle [a broad/wide horizontal beam pattern], or flood). however, in actual use the artifact-like anomalies in the beam's appearance are *NOT* at all objectionable. anyone who is used to a good incandescent/Xenon headlamp beam probably won't mind the beam patterns of the H1 at all. IMO, while NOT up to LED beam pattern standards (ignore Cree-donuts and rings), it is better than Xenon headlamp beams that i've used, or at the very least as good as some of the better Xenon headlamp beams in terms of appearance and artifacts.

only other point of note at this time is that while a "Herculean" effort is *NOT* required to actuate the buttons (two of them to be precise - ON/OFF/MODE selection button w/a 2sec press and hold to turn OFF, and a BOOST button), the buttons, IMO, required just a tad too much force to actuate - though this can probably prevent accidental "turn-on" in one's pack.

 

[uk_caver]

So where are the beamshots?

They do at least have illuminance maps on the Dosun site.
I guess it's hard to do a good beamshot of both parts of the beam in operation, hence their drawings.

(PS another possibly useful feature of the downfiring-into-partial-reflector geometry is that as well as giving good downspill, there's very little upspill above the spot, which means it's a very nice non-dazzling arrangement if looking at someone wearing one, as long as they're directing the spot at or below your chin.)

 

[half-watt]

another possibly useful feature of the downfiring-into-partial-reflector geometry is that as well as giving good downspill, there's very little upspill above the spot, which means it's a very nice non-dazzling arrangement if looking at someone wearing one, as long as they're directing the spot at or below your chin.)

EXCELLENT POINT!! wish i had mentioned it in a Post. good observation on your part. i noticed the sharp cut-off (almost like in some auto HID headlights) in the "eagle" beam pattern, but failed to really take notice of it in the "spot" (other than the fact that the "spot" is somewhat well defined, but still with decent spill).

 

[uk_caver]

I can't see any real value in a boost that's only seemingly ~10% higher than the regular Hi output level, beyond allowing the packaging/marketing to carry a number above 100 lumens despite any given lamp hardly ever (possibly never) being likely to be run at that level.
Practically speaking, it seems likely to be almost totally pointless.

 

[uk_caver]

The lack of upspill is most easily noticeable when *other* people are using lights in a face-to-face group situation.
Otherwise, except maybe if using a light for crawling or climbing, you may well not notice that feature of the beam.
However, even face-to-face, it's easy to simply not notice being dazzled, rather than to notice not being dazzled.

 

[half-watt]

I can't see any real value in a boost that's only seemingly ~10% higher than the regular Hi output level, beyond allowing the packaging/marketing to carry a number above 100 lumens despite any given lamp hardly ever (possibly never) being likely to be run at that level...

another excellent point. DoSun's claim of 120% figure output for their BOOST increase over HI/100% output differ's from their actual "claimed" lumen numbers (104 v. 93.6) which have the "Boost" only ~11% higher.

however, indoors, an increase "Boosted" output is noticeable to the "eye" (not sure what a light meter would show - that would be interesting), and i get the impression that it's at least 33% (or a bit more) brighter. i only say this b/c some years ago, while playing with a Photon Fusion headlamp, i learned that 33% is 'bout the smallest increase in light output that i can easily notice w/o having to switch back-and-forth b/t modes multiple times to make sure that i'm really perceiving (and not imagining) an increase in light output.

again, it's daylight here, and my darkened basement is my only testing "grounds", so to speak, at this point in time. indoors in the basement the BOOST difference is easily noticeable both on white wall and the basement workshop which doesn't have any white walls - just studs, wood, concrete, tools, and equipment, etc.. don't know, however, if BOOST will be noticeable out in the forest on a hike or in camp at night; probably not much or at all if it's really only a 10% to 20% increase in brightness. not a caver, so i won't speculate at all in its use for caving (it's probably *NOT* robust enough in construction, but then again, the Petzl Duo is of plastic construction and is used for caving, by some cavers at least - ok, ok,...so, i speculated...).


EDIT:

HI/100% burn-time test is at ~03:28 on 3xAA Sanyo 2700 NiMH.

while extremely imprecise, to say the least, the H1 output still appears to be as bright as when i started. however, i'd be kidding myself if i asserted that the light output appears the same to my eye now as when i started the "test" (i almost hesitate to call it a "test"). how am i to really know if less Lux is being output without a light meter? all i'm saying is that it is still quite bright and i can't tell if it has dimmed any.

also, DoSun warns NOT to touch the aluminum backplate on the head as it can get rather hot when used for a period of time on the higher output mode(s).

don't know if it the reduced voltage (i.e., as cp. to alk. cells) of the NiMH cells is the reason, but the Al backplate has never really gotten too hot to touch, just quite warm or slightly hot (could hold my fingertips there for several seconds with no problem; removed them NOT b/c of heat). checking now, maybe light output is down a bit as the Al backplate, while still very warm, seems to me to be just a bit cooler than when i started and the cell voltage was higher. just held my fingertips there for 10s and there is no doubt that i would NOT have to remove them due to heat even one or two minutes later (or longer).

 

[uk_caver]

I'd certainly agree with you that something like a 30% brightness difference is about the smallest that might be reliably detected by eye with even the briefest interruption while changing power levels.

What happens as the cells discharge - does it switch levels, slowly fade, or suck the cells dry?

Heatsink-wise, unless there was a large mass of aluminium acting as a thermal store, I'd guess that with only a Watt or so of heat going in, if you could hold your fingers on the heatsink for more than a few seconds without pain, you could probably hold them there indefinitely.

(Underground, Duos actually seem to do fairly well, though they are designed to be easily boltable onto helmets, not relying on elastic straps like most other lamps. However, unlike most headtorches, they are designed by a company that was started by a serious caver, and which is a major supplier of caving hardware.)

 

[cat]

Why do those lumens numbers seem to be a bit low, like those given at fenix-store for the R1 ? Cree Q5 claims usually higher than that (if that is what it is.)

half-watt, no camera, ok,...but have yo seen the beamshots on Szemhazai's review of the Primus Race? What would you say, how the Dosun would compare to that?

 

[half-watt]

uk_c, good info. many thanks.

-----------------------------------------

DoSun H1 Hi/100% output burntime test on Sanyo 2700 NiMH cells:

it is now approx. 6h 10m since the "test" was started and the output has dimmed quite noticeably (if it was dark, i would have undoubtedly noticed it sooner). probably 10% or so of the starting brightness. it is still much more than sufficient for proximity/task lighting, but i wouldn't want to use it in the forest to walk much more than a simple footpath at night.

adjusted for "spot" output, it is probably 100% brighter than or 2x as bright as (against a white wall in my basement) a Muyshondt Nautilus on its LOW output mode (supposedly ~4 lumen) running off of a fairly fresh CR123A. so this is easily still outputting 8+ lumens after 6h 10m of running on HI/100% output. the spot is much brighter, i'm trying to compare the overall brightness (hence my mentioning lumens, plus i don't have Lux measurements for the Nautilus, only claimed lumen numbers).

even as i've begun to type this, the brightness is dropping off further. i'll have to pop the NiMH cells out and check their %SOC. just a moment...

ok, back. here are the results:

none of the cells lights even the 10% LED on my ZTS MB-1 battery tester. the cells have cooled a bit to the touch (they don't feel warm at all, so little current is being pulled out of them), and their resting, no load voltage (i know, i know...) is

+1.04VDC, +0.92VDC, and +0.94VDC.

given their current temperature (NOT warm to the touch), i don't expect too much voltage recovery by letting the cells rest.

putting them back in the H1 and comparing again to the Muyshondt Nautilus on low, it is no different to the "eye" than before. still looks to be at least 2x as bright when adjusted for "spot" output as compared to the Nautilus on LOW, and approx just as bright when adjusted for "flood".

i hope that this amateurish experiment gives some idea of the much better performance one can expect from the H1 when using NiMH cells as opposed to alkaline cells.

if anyone has any questions, just Post back and i'll attempt to answer them.

 

[chadne]

I got mine today, but it isn't dark here yet
The only thing I notice is that the battery pack seems big, and the part that physically holds the batteries in place appears screwed into the unit, which might mean I could put in a proprietary battery back -- rectangular lipo, or something like that. I haven't taken the head apart, but metal faces the outside. which hopefully means a good heat path exists. It might be a good candidate for a the p7 headlamp build I'm planning (okay, maybe the new four chip cree is a better idea, but that wasn't announced when I bought the p7's)

 

[clg0159]

Would someone owning this headlamp please post some beamshots.

 

[DragonFlame]

I'm also looking forward to beamshots ...
It might be (at last) the headlamp to offer both a concentrated beam for scouting further ahead and some diffused light right in front of you ....
I'd also be curious about a nice plotted runtime test ...

 

[half-watt]

cat, my apologies, only just now noticed that your Post addressed me.

Why do those lumens numbers seem to be a bit low, like those given at fenix-store for the R1 ? Cree Q5 claims usually higher than that (if that is what it is.)

first off, while i like the H1 a lot (but NOT as much as a PT Apex or MyoXP '08 model), i can't comment on the R1 (i know, not addressed to me) since mine showed up obviously used, greasy, scratched bezel, and fried electronics. however, the R6 that i have is very nice construction, but lacking in output, and all those extra modes are, IMO, "fluff" modes that will almost never be used.

also, compared to some other lights that i have, the R6 is dim (i'm expecting that the R1 will compare similarly, but have no empirical evidence to base this statement on. so, it's merely my opinion. YMMV.) and, unless those other lights (not SF lights in this case) really underguesstimate their light outputs, the R6 is in no way producing the numbers they claim, comparatively speaking. for example, a Ra Twisty-100-TW on its default MED o.p. level of 17lm (Mfr. Claimed) is clearly brighter than my particular R6 on its 48lm (again, Mr. Claimed) o.p. level. do the math, the claimed 48lm value is nearly 3x higher than the 17lm value and the claimed 17lm of the Twisty is brighter!!


now, on to your H1 questions:

half-watt, no camera, ok,...but have yo seen the beamshots on Szemhazai's review of the Primus Race? What would you say, how the Dosun would compare to that?

yes. i've seen the beamshots. i also own a Primus Race and it's output is warmer and quite pristine in appearance - quite nice beam pattern, IMO. in comparison, the H1, which again i like a lot, has the ugliest beam pattern of any LED headlamp or LED flashlight that i've ever seen as it's filled with artifacts from the fancy reflector. however, this doesn't bother me in the least. it reminds me (other than its much cooler/whiter beam output) a bit of an incadescent/Xenon headlamp's beam pattern which very often had artifacts unless the reflector was quite stippled.

the H1, IMO, makes up for the artifacts with its 3-way beam pattern selection capability and the usefulness of its beam patterns - the spot and eagle have very clearly defined and sharp cut-offs with little spill beyond the portions of the beam patterns that cut-off, yet there is sufficient spill in the non-cutoff areas/azimuths of the beam pattern. the H1 also has some pretty decent burntimes, and even more so on NiMH cells (~6h on HI in my own testing).

however, i'd definitely rate it behind a MyoXP '08 version headlamp. given the choice between the two, i'd go for the unregulated MyoXP '08 headlamp.

'nuff said. my two shekels. YMMV.

 

[chadne]

I have to agree with the ugly beam statements. If you consider yourself a beam purist, this is so far from being the light for you it's not even funny. The decent build (close to PT apex), and the variable pattern are a great idea. I was using the flood to take out the trash last night and loved it -- I use the 4 leds on my apex for flood, and then switch to spot to see stuff further out, so this is perfect for that as it is brighter than the apex.. Someone complained about dual strobe. I used slow strobe on my apex to hike several miles in the dark since my buddy was using my backup light and it worked great at providing bright light when the battery was nearly dead. The fast strobe is also probably useful if you need to annoy someone -- as in get their attention, or go into convulsions....

If I didn't have to sign up for a spam inducing photo sharing site, I'd put pics up.

 

[clg0159]

Still interested in seeing the beamshots, I don't really care that the beam is not perfect!

 

[Mercaptan]

If I didn't have to sign up for a spam inducing photo sharing site, I'd put pics up.

www.imageshack.us

 

[cat]

Thanks, half-watt, that helps a lot. Sorry about the belated response. I need to take a closer look at the Myo XP. And consider that I probably need more focussed beam more than anything else.