~
I'd miss the speaker trees ........
that always broke out your side window as you drove off .
~
~
I'd miss the speaker trees ........
that always broke out your side window as you drove off .
~
~ "She" says ...... I have ... TooManyGizmos ~
W/L is apparently in trouble with George Lucas over the whole Lightsaber thing...
No matter how well focused, it's only 1 watt. Blink reflex is going to kick in and keep eye exposure to a lot less than a second. 1 watt for 1/4 of a second is not going to significantly heat up more than a tiny volume of eye tissue.
Rough calculations.
Assume the eye is about the size of a 2 cm cube.
It's mostly water, so it's about 8 cc or 8 ml.
8 ml weighs about 0.016 lbs.
1 watt for 1/4 second is 1/4 joule.
1/4 joule is about 0.00025 BTU
0.00025 BTU will heat 0.016 lbs of water by 0.015 degrees F.
Yes, you may burn a small spot, but I don't see how you're going to heat up more than a small spot on the eye in the 1/4 second or so it takes to blink.
1/4 Joule will only boil 0.00014 grams of water, so you're not going to cause much damage to a widespread area from steam.
I will admit to the possibility that there is some other effect that might cause blindness over a larger area, but I haven't heard of it yet.
Yes, I can easily believe damage to a small spot on the retina because it's focused on a tiny area. However, for widespread damage, 1 watt is simply not that much power in terms of causing heat damage over anything other than the tiniest area for such a short exposure time.
If once you start down the light path, forever will it dominate your destiny, consume you it will.
The part of the eye that isn't just jelly is VERY small, and able to heat up VERY fast when light falls on it... if that's not that much energy, explain to me why a hundred mW will still cause instant blindness (MUCH faster than you can blink). If you think a watt is no big deal, go ahead, use it without goggles. Just don't sue anyone when you hear that "pop" and the innards of your eye are destroyed.
also WTF is with george lucas suing wicked? Seriously? wtf....
That sounds like an urban legend. I recall the main reason given for the decline and eventual disappearance of drive-in theaters was economics. Land in most areas became too valuable to use for a drive-in theater, which in many parts can only operate in the warmer months of the year. Other factors were the widespread adoption of daylight-savings time, which limited showtime hours (particularly in the summer), and the invention of color television, which had people spending more time watching home entertainment. The shrinking interior-size of cars may have played a part, as well. All of these factors together made drive-ins unprofitable.
Designing a projector with adequate cooling to prevent from melting film shouldn't be difficult. I'm sure modern IMAX projectors that display on screens up to eight stories high are many times more powerful than old-time drive-in projectors. Besides, an outdoor drive-in projector doesn't really need to be more powerful than an indoor projector. I remember drive-ins being a lot "dimmer" than indoor movies, so it wouldn't surprise me if they used the same projectors.
Unfortunately, I don't think anything is going to bring back the drive-in theater. The drive-in is a charming relic of a bygone era.
Try reading before posting next time.
I agree that it might cause a pinhole burn in your retina. I don't see any effect that would cause intense light on one spot on the retina to spread out and cause heating across the whole of the retina. Even if you intensely heat up one small section of the retina for a very short period of time, I see no mechanism to rapidly spread the heat over the whole retina.
I'm an engineer and do understand what a watt is, how much heat it generates, and how thermodynamics and heat flow works.
Unless the fluid in your eye is liquid helium, it's not some sort of heat superconductor that's going to instantly spread the heat over the whole retina. Heat will flow outward in three dimensions through the tissue of your eye and the temperature will drop rapidly from the pinpoint spot heated by the laser.
I've seen no indication that a few hundred mW will instantly cause blindness over the whole visual field. Yes, it may cause a pinhole burn in the retina.
Remember, they use lasers all the time to reattach retinas or do other things in the eye. It burns a tiny spot on the retina, it doesn't magically spread over the whole retina and burn it. Yes, it may cause a small blind spot where the laser hits. It's like spot welding on the retina.
Remember, I said it might damage the retina and leave a blind spot, so no, thanks, I'm not going to be willing to burn holes in my retina to prove you wrong. You're welcome to try and pop your own eyeballs if you want to. Buy a laser, get some cow eyeballs, and have fun. They won't pop with a few seconds of exposure.
As far as something going pop, try reading again. Turning 0.14 milligrams of water into steam is not going to make your eyeball pop.
However, after a little thought, I realize you might be able to blind the whole eye if you hit the optic nerve head and burned the head of the optic nerve. However, that's a very tiny target to hit. I suspect it would be hard to do that much damage that quickly. There were also some military laser rangefinders that were known to rupture blood vessels in the eye and cause blindness by filling the eye with blood. I believe they were very high power infrared lasers, though.
Once again, in case you're STILL not reading what's posted here, It's a really BAD idea to point one of these into your eye or use one without proper eye protection. I think it's entirely possible to almost instantly end up with blindness in a small spot of your visual field, if not worse. Picture it like when a camera flash leaves a blind spot in your vision, but it NEVER goes away.
I'll go further and say it's a bad idea for any of us "normal" people to use one of these 1 W lasers at all. Entirely too much chance to accidentally get a reflection off of something and damage someone's vision.
As mom said, "It's all fun and games until someone loses an eye."
If once you start down the light path, forever will it dominate your destiny, consume you it will.
I just got an email from WL saying:
Thank you for purchasing our Spyder III Arctic <1W portable laser.
We sincerely appreciate your patience for bearing with us while we
prepare to ship your order to you. We have an important
announcement that will affect your order.
Due to the overwhelming popularity and media coverage of the S3
Arctic laser, we are implementing an electronic switch upgrade to
the laser for all customers, free of charge. This upgrade will
enable the following functional and safety features on your S3
Arctic laser:
1) Adjustable Power Mode : Low power and high power modes are now
selectable. Laser's default power mode is low power mode.
2) Adjustable Wave Mode : Pulse mode and constant wave modes are
now selectable. Laser's default wave mode is pulse mode.
3) Secure Lock/Unlock Mode : The laser can now be locked and
unlocked electronically to prevent unauthorized usage. Laser's
default secure mode is locked mode.
4) Training Lens : A replaceable training lens will be installed on
each laser that reduces the power output by 80% to prevent
accidents for new users. Once training is completed, user may replace
the training lens with the included standard lens for maximum power.
Because our customers' safety and well-being is our highest
concern, we feel it is our social responsibility to implement these
features free of charge. This enables new users as well as
experienced users to use our products with extra protection.
As one of the world's leading laser manufacturers, we feel as
passionately about our customer's safety as advancing laser
technology and paving the path towards the future.
We expect to begin shipments of the new S3 Arctic by July 15th,
2010, in 2 weeks time.
If for professional reasons you would like to receive the original,
non-upgraded model with less functionality, please provide the
following information with your order number to
[link removed - DM51]
1) Scanned government-issued photo ID card
2) Certificate of professional requirement that matches name on
above ID card (IE: Law Enforcement, Scientific, Medical, Military
license)
Thank you again for your patience and we look forward to serving
you again soon.
P.S. Please disregard this email if you are not a S3 Arctic
purchaser. Stay tuned for more important news and offers from Wicked Lasers.
Best Regards,
[details removed - DM51]
Last edited by DM51; 07-01-2010 at 02:04 AM.
That's a lot of failsafes; the laser starts out locked AND low power AND pulse modulated AND lens-reduced.. I'm not sure what else you could do to protect the end user..
This is an exciting update. I don't have that email yet....
What do I do now? Low power modes seem like a great addition, but I kinda want an on/off version too.
edit: WHOOPS I suppose I don't have a certificate of professional requirement. Although I could use this at work...
Three fail-safes or three hundred.... you can't protect the end users from their own stupidity, er, or "igorance".![]()
Last edited by ejot; 06-30-2010 at 10:59 PM.
Caution: if you provide a scanned driver's license as an ID, and your ID has your SSN on it, I strongly recommend blurring out at least six of the nine digits of the number before sending it to anyone, not just W/L. There are very few agencies that have the legal right to require your full SSN.
I read your whole post. I thought I made it very clear in mine that the whole eye doesn't need to be heated... just a very small fraction of it. THE WHOLE RETINA IS DESTROYED at these powers. I'm not an ophthalmologist, I don't know the mechanisms through which it is destroyed but the fact is in a human eye exposure to a small part results in destruction of a lot more. And as for the pop-I never suggested your eye would physically pop-it's well known among laserists that destruction of retinal cells not only causes blindness, but a loud popping noise perceivable only to the person who just lost an eye. Once again, I'm not sure as to the mechanisms but this kind of violent stimulation manifests itself as a sound. And you must keep in mind the eye is NOT made of liquid helium, just as you said. Poor thermal conductivity in human tissue means that all of that heat stays in one small area rather than harmlessly dissipating throughout the whole eyeball. Even in relatively heat conductive mediums like water, if you put a piece of electric tape in a glass of water and shine a laser at the bottom of the tape, the water will boil. If the heat was distributed, you'd get a practically nonexistent increase in heat. But nonetheless, you still see boiling.
Well, normally, I'd say you don't know what you're talking about, but SINCE YOU TYPED IN ALL CAPS, it must be true.
Sorry, but you still have no idea what you're talking about.
However, it's a really bad idea to shine one of these things into anyone's eyes. Some damage to vision is likely.
As for boiling, remember, 1 watt laser, 1/4 of a second.
If once you start down the light path, forever will it dominate your destiny, consume you it will.
Well, this lasers aperture is 1.5mm. That's about as wide as the entire pupil in a lighted room. So even at extremely close range the beam is wide enough to cover everything it needs to make you 100% blind (in one eye anyway). After just 25 meters the beam will be wide enough to cover your entire eyeball, but still powerful enough to make you permanently blind in 1/100th of a second (I think the blink reflex is .25 seconds? ) So yeah, total blindness is what you're looking at with this thing, not a small "black spot"
The lasers they use for eye surgery are focused to an incredibly small dot size, and are running at much, much less power than this thing.
I think we can agree that it is bad to get this thing into your eyes. Whether not it is permanent is beyond me, and probably, beyond everyone here.
Anyway, I have had a 500mW green pointed at my face from about 400ft and I received no permanent damage (that I know of). It was a Viasho so it was IR filtered. I had it on a tripod and my dumbass friends thought it'd be funny to point it at me. Luckily this laser has quite the divergence.
Also I have always wondered, is there a difference between getting lased at night time or being lased at day time, as far as damages to your eyes go.
Really? I thought they where 50 Watts of Infra Red.
Last edited by SmurfTacular; 07-01-2010 at 07:01 AM.
double post
50 Watts!?!? Are you sure? wow
This wikipedia article ( http://en.wikipedia.org/wiki/LASIK ) talks about nanoseconds and femtoseconds of exposure though, which is much less than the 1/100th and 1/4 seconds we were talking about. And like I said, I'm sure they are focused to a tiny dot, instead of flooding the eye like the arctic would.
No, I'm not sure! Im not a doctor.
Im basing that on the fact that most industrial lasers of all kind are 50W IR lasers. The more I think about it, the more silly it seems of using a 50W IR laser millimeter away from somebody's eye. Probably not even close to 50W.
Last edited by SmurfTacular; 07-01-2010 at 07:34 AM.
Also, it looks like they actually use UV lasers (193nm). This article says UV is largely absorbed by the cornea and lens: http://en.wikipedia.org/wiki/Laser_safety
So, those lasers are probably used specifically not to damage the retina.
I dunno, when I look at bulb filament, which is at least 1.5mm long and nearly 1.5mm wide (due to the spiraling), it doesn't 'fill my entire pupil' in any way. It's a very bright line in my vision. Given what little I know about the retina, this means that my eyes focused on the filament MUST be focusing the light onto a very small part of my retina. Deliberately defocusing my eyes can make a point source of light appear large and fuzzy - so in some situations you could have a light source you aren't focused on fill your retina - but if you are focused on it then it will appear to be its apparent size - by definition of the apparent size!
The blue laser won't have much effect on the lens and jelly of the eye - they use IR (oops, UV) lasers in surgery because the eyes are, unsurprisingly, nearly transparent to visible light. As long as you aren't focused on the bridge of your nose, the WL laser, like any other small source, will appear to be a point because it is focused by your eye onto a small part of the retina. If your eye didn't focus small things onto small parts of the retina, we wouldn't be able to see very well at all.
Lawsuit: In July 2001, LucasArts sued a medical company for calling a laser-guided device a Light Saber. LucasArts defends their copyright of the name "Lightsaber," and apparently things similar to it. But only reviewers have called the WL device a "lightsaber," I suspect WL knew of the pitfalls of using the Jedi weapon without having The Force. It's surprising though, how many unlicensed things are being sold on eBay and so on with the name 'Lightsaber.' I guess LucasArts did the math and figured out how much money WL will make from this. I can't find a particular lightsaber that the Arctic Pro is a copy of.
The article describing it "designed to look like a lightsaber from Star Wars." But I wasn't aware that any spiffy-looking cylinder (even one that emits light!) was an "Infringing device." Look out custom CPF makers, George might decide he wants to sample your work for free. Don't make 'em TOO nifty.
Who was it who made the giant-lens light with a 3 mRad divergence recently? It had about half a meter between the LED and the lens. Look out!
My biggest light-hog is my camera.
Alright, you know what? I'm tired of arguing with you. You've got your head up your butt, and refuse to realize some very simple medical truths because some basic math that only applies to general situations appears to say otherwise... And as for boiling, watch this. http://www.youtube.com/watch?v=GLO9NqE4Jxs . Oh look, the water's boiling in a small area even though the laser's only putting out enough energy to heat the whole glass a fraction of a degree! And imagine that, water probably has much better thermal conductivity than protein-filled vitreous humor...big surprise, looks like a one watt laser has no problem boiling a small area, like the cornea!
Found on YouTube; 1W 445nm Blue Laser Burning Tests: http://www.youtube.com/watch?v=__5CpKlr4-4
Features electrical tape, leather, wood, matches, an LED, some plastic. If you doubt that a 1W laser can really do much in the way of burning things, you'll definitely want to see this..
Last edited by StarHalo; 07-01-2010 at 12:21 PM.
I don't want to argue, and I am concerned about laser safety. But if the eye's lens is designed to focus things onto the retina, it seems like a small apparent source - no matter how much of the pupil it illuminates - will resolve to a very small area of the retina. For example, a lightbulb filament illuminates my entire pupil quite uniformly. If the eye's lens didn't focus small things to small areas on the retina, it seems like we would be absolutely unable to see.
However, there is a mechanism that causes widespread retinal damage, and it seems to be similar to what you were talking about. WickedLasers acknowledges this type of damage, although I think they should emphasize it further. The energy from the laser, concentrated to a tiny point on the retina, can produce a pulse of pressure (some report hearing it as a pop!) that permanently damages a large area of the retina. Apollo Cree is right that neither the whole eye nor retinal surface are heated much, but that's not needed to damage the whole retina. I haven't been able to find an energy threshold leading to acoustic damage, but lasers in near-IR and visible light are of the right frequencies. UV light would mainly denature the cornea.
My biggest light-hog is my camera.
lol, it works in Firefox, but IE loads the video then goes to the home screen..
Here's the correct-for-everybody link: http://www.youtube.com/watch?v=__5CpKlr4-4
1) Adjustable Power Mode : Low power and high power modes are now
selectable. Laser's default power mode is low power mode.
That’s cool, I don’t mind that much.
2) Adjustable Wave Mode : Pulse mode and constant wave modes are
now selectable. Laser's default wave mode is pulse mode.
What does this mean? Like momentary mode and constant on?
3) Secure Lock/Unlock Mode : The laser can now be locked and
unlocked electronically to prevent unauthorized usage. Laser's
default secure mode is locked mode.
How do you electronically lock something? What do we have to like press the same button in some sort of cryptic pattern every time we need to use this thing? That will get very annoying very fast!
4) Training Lens : A replaceable training lens will be installed on
each laser that reduces the power output by 80% to prevent
accidents for new users. Once training is completed, user may replace
the training lens with the included standard lens for maximum power.
This better not be like an internal lens we have to replace, or any thing technical, I’m not buying an assembly required product, I hope it’s just a simple lens cap on the end, or like the lens in a flashlight secured by the bezel
.
Because our customers' safety and well-being is our highest
concern, we feel it is our social responsibility to implement these
features free of charge. This enables new users as well as
experienced users to use our products with extra protection.
As one of the world's leading laser manufacturers, we feel as
passionately about our customer's safety as advancing laser
technology and paving the path towards the future.
We expect to begin shipments of the new S3 Arctic by July 15th,
2010, in 2 weeks time.
This isn’t that big of a deal, but if this thing doesn’t have memory and we have to do some sort of cryptic button pushing, change to high mode, change to constant on mode-EVERY TIMER we want to turn this on it will really suck!
“What do you mean LEDs are more efficient then Incans?”, that’s just what they want you to think! It’s a Conspiracy, Man!
BTW wicked's new "pulsed mode" is only at 6 hertz- WTF?
Very nicely put, thank you for clarifying that purely thermal effects are not the sole contributor to retinal damage. The photoacoustic component is probably the dominant damage mechanism in this case, likely involving optic inertial cavitation. Essentially, the incident energy forms small bubbles that violently collapse, yielding highly localized areas of extreme temp and pressure (potentially thousands of degrees C and thousands of psi's over a very small area, and for a very short time).
Cavitation damage creates nucleation sites for more bubbles, creating more cavitation damage, creating more bubbles, creating more damage..... I'm speculating here, but I suspect that is part of the reason why a small but intense projection onto the retina can end up destroying the entire thing. Likely it's also the source of the reported "pop".
Google image "cavitation damage" to see what it can do to poorly designed mechanical systems. We actually exploit a similar effect in the semiconductor industry to clean wafers, in fact I just finished designing such a system.