Creating a Visible Beam with LED

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Bo Participant Join Date: Dec 2008 Posts: 4	Creating a Visible Beam with LED 12/02/2008 12:42 PM
	Is it possible to create a visible beam using a LED? Basically I would like to know if a LED can produce a beam like a laser does. Thanks in advance.
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#3 "Re: Creating a visible beam with a LED" by bhankiii on 12/02/2008 3:59 PM (score 2)
#4 "Re: Creating a visible beam with a LED" by Bayes on 12/02/2008 4:12 PM (score 3)
#9 "Re: Creating a visible beam with a LED" by Bayes on 12/02/2008 9:33 PM (score 5)
#12 "Re: Creating a visible beam with a LED" by Gwen.Stouthuysen on 12/03/2008 2:55 AM (score 2)
#15 "Re: Creating a Visible Beam with LED" by scrump on 12/03/2008 10:22 AM (score 2)
#19 "Re: Creating a Visible Beam with LED" by Anonymous Poster on 12/03/2008 11:03 PM (score 2)

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#14 "Re: Creating a Visible Beam with LED" by Andy Germany on 12/03/2008 7:53 AM (score 1)
#17 "Re: Creating a Visible Beam with LED" by Bill ML on 12/03/2008 1:38 PM (score 1)

beatenblood Associate Join Date: Dec 2008 Posts: 30 Good Answers: 1	#1 Re: Creating a visible beam with a LED 12/02/2008 1:00 PM
	hi.. a light emitting diode emits visible light, the only difference is that the output is too dispersed.. it is not as concentrated as the LASERS.. and the light rays from the LEDs are usually converted into finer beams mostly by using a "concentrator" that produces a collimated fine beam of a much reduced and narrow beam angle
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Bo Participant Join Date: Dec 2008 Posts: 4	#2 In reply to #1 Re: Creating a visible beam with a LED 12/02/2008 2:38 PM
	Thank you so much for the quick response. So if I understand this correctly I could use a "concentrator" that would in fact not disperse the beam, which would in turn make the beam visible along the same line that a laser beam is visible?
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bhankiii Guru Join Date: Sep 2006 Location: El Lago, Texas, USA Posts: 2639 Good Answers: 65	#3 Re: Creating a visible beam with a LED 12/02/2008 3:59 PM
	No - an LED cannot produce a beam like a laser does, any more than a light bulb can. Laser light is coherent - all the photons vibrate the same way, and so the beam doesn't spread. LED light is not coherent, although you can find LEDs with a spread of 10 degrees or less. You can, as the other poster suggests, use optics to create something of a stable beam. But the simple solution is to use a laser diode, which you'll find inside your CD or DVD player.
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CJMcGill Guru Join Date: Jul 2008 Location: SoCal USA Posts: 556 Good Answers: 23	#11 In reply to #3 Re: Creating a visible beam with a LED 12/03/2008 12:00 AM
	Mr B, isn't a 'laser diode' technically an LED by definition? And is it not multiplied by reflection through a crystal to magnify and align it so as to concentrate its output? It's been a while since I read about these, and the technology may have changed some, but I was surprised by your casual reference to a laser diode in explaining that it is not a Light Emitting Diode.. Care to expand on this for us? __________________ I do not 'know it all', but i will admit that I would like to. CJM
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Anonymous Poster	#13 In reply to #11 Re: Creating a visible beam with a LED 12/03/2008 4:10 AM
	A laser Diode works by having a very fine "tube" of active area running throught the center of the diode and reflective ends so the photons get reflected back and forward exciting other photons in the process until they break out of the end. this gives a fairly concentrated beam with a little scatter from photons which have been bouncing from side to side of the "tube". In comparison an LED has a spot of active area on top of the laser which just emits light when it is powered. and any colomnisation is due to the lense in the cap of the package.
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Anonymous Poster	#35 In reply to #3 Re: Creating a visible beam with a LED 12/22/2008 12:26 AM
	See here: www.elecosn.com Here are dimmable LED Bulb, and LED incandescent bulb
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Bayes The Engineer Join Date: Feb 2005 Location: Albany, New York Posts: 5060 Good Answers: 129	#4 Re: Creating a visible beam with a LED 12/02/2008 4:12 PM
	Laser beams can be seen, because the light emitted is scattering There a thousand million dusty specs, off of which the light reflects, Since a laser has coherence (That just means low divergence), The scattered light we call the beam is bright due to the photon density. But LEDs have coherence not, because of their high divergence output, The light produced is not so densely packed to produce a beam we can detect, If you collimate the light with optics, you may have a beam for a little bit, But eventually the beam widens and it's brightness goes to...... Or to answer your question another way, no, because LED light is not coherent. However you can make a nice flashlight.
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bhankiii Guru Join Date: Sep 2006 Location: El Lago, Texas, USA Posts: 2639 Good Answers: 65	#5 In reply to #4 Re: Creating a visible beam with a LED 12/02/2008 4:29 PM
	what - no rhyming pentameter?
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Bayes The Engineer Join Date: Feb 2005 Location: Albany, New York Posts: 5060 Good Answers: 129	#10 In reply to #5 Re: Creating a visible beam with a LED 12/02/2008 9:44 PM
	I wouldn't write my worst enemies poetry in pentameter.....
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Bo Participant Join Date: Dec 2008 Posts: 4	#6 In reply to #4 Re: Creating a visible beam with a LED 12/02/2008 5:07 PM
	So if I want to use LED (due to cost) and only want the beam to be visible for about 3 feet I might be able to accomplish this by using the right optics? Of course I haven't even talked about being able to see the beam outdoors in full daylight. All - Thanks for the replies. Very insightful. You must forgive my ignorance but I am just an old retired Marine trying to develop a product.
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JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#7 In reply to #6 Re: Creating a visible beam with a LED 12/02/2008 6:57 PM
	Depending how many you're going to make, you may find that the cost of the optics+LED is greater than that of a laser diode. You can get laser pointers/key rings etc. in the pound shop these days. (£1 ≈ $1.50). __________________ "Love justice, you who rule the world" - Dante Alighieri
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Bo Participant Join Date: Dec 2008 Posts: 4	#8 In reply to #7 Re: Creating a visible beam with a LED 12/02/2008 8:36 PM
	JohnDG, Thanks for the info. The only concern I have with a laser is to be viewed outdoors in full sunlight it appears that only a green laser will work. From my research the green laser will cost to much to make the product cost effective. Perhaps I need to start looking a little more into this. Thanks,
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Bayes The Engineer Join Date: Feb 2005 Location: Albany, New York Posts: 5060 Good Answers: 129	#9 In reply to #8 Re: Creating a visible beam with a LED 12/02/2008 9:33 PM
	Bo, Don't know how much you're willing to spend, but here is a green laser pointer for $14. It's only 5mW. I'm not sure if you know, but the stronger the power, the more visible the laser will be (because of more scattering). http://www.bestofferbuy.com/5mw-powerful-green-laser-pointer-pen-p-950.html?currency=USD&utm_source=gbase&utm_medium=cse&utm_campaign=gbase As you have mentioned, the eye is most sensitive to green light, meaning that given three different lasers, red, blue, green, at the same power, the green would seem brightest, then the Red, then the blue. Here is a graph below of the eye's sensitivity to color: The point I'm trying to make here is that a 10 or 15 mW red laser pointer might be brighter than a 5 mW green laser and could be cheaper since the red ones are easier to make. You'll have to look into it. Also keep in mind that air attenuates blue and green light more than red light. So a red laser loses less intensity over distance, but this is a secondary effect unless your application is involving a long distance. Attenuation curve:
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Gwen.Stouthuysen Guru Join Date: Aug 2006 Location: Glabbeek, Belgium Posts: 1480 Good Answers: 28	#12 In reply to #7 Re: Creating a visible beam with a LED 12/03/2008 2:55 AM
	But laser diodes also need the beam shaping and collimating to create the nice beam that comes out of a pointer. I assume that the poster will try to make a laser sword, do never forget that if you want a nicely visible section of 1m the next 100m will also be visible. __________________ "Here we are now, entertain us"
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Anonymous Poster	#16 In reply to #12 Re: Creating a visible beam with a LED 12/03/2008 10:22 AM
	"I assume that the poster will try to make a laser sword"I assume that the poster will try to make a laser sword...." I hope not,,,, we'll have a bunch of blind children running around..... prehaps someone should mention the effects of laser light on a persons vision, since this is to be used outdoors and must be strong enough to be seen in daylight.....
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bwire Guru Join Date: Dec 2007 Location: Upper Mid-west USA Posts: 7498 Good Answers: 97	#36 In reply to #4 Re: Creating a visible beam with a LED 12/22/2008 2:54 AM
	And when using good LED flash lights a discernable can be seen if fog or dusty conditions exist too. __________________ If death came with a warning there would be a whole lot less of it.
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Andy Germany Guru Join Date: Sep 2006 Location: Near Frankfurt am Main, Germany. 50.390866N, 8.884827E Posts: 17996 Good Answers: 200	#14 Re: Creating a Visible Beam with LED 12/03/2008 7:53 AM
	It might be possible to take a powerfull green LED and use a laser colliminator (optics) to get a reasonably good beam over 10 meters or so, but as many have pointed out, a green laser pointer is not that expensive, so is making your own worthwhile? Probably not!!! Coherent (laser) light is far better for such purposes than incoherent light (LEDs and other light sources). __________________ "What others say about you reveals more about them, than it does you." Anon.
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scrump Member Join Date: Dec 2008 Location: Baton Rouge Posts: 5 Good Answers: 1	#15 Re: Creating a Visible Beam with LED 12/03/2008 10:22 AM
	It may be getting a little off topic, but here is a site describing how to make your own laser powerful enough to burn: http://www.felesmagus.com/pages/lasers-howto.html You can look on YouTube and see videos where people have made them and burned objects. Please keep in mind that even a little 5mW laser can permanently damage your eye. A more powerful laser can seriously blind someone before they can even react and close their eyelid. While you may be careful and always point it away from yourself, a beam that is accidentally reflected in an unpredicted direction can yield disastrous results on a friend or family member's eye. I personally think that it is really not a good idea to create and/or use a powerful laser in an uncontrolled environment. From your discussion, I gather that you want a visible beam. This search may lead you to consider using a more powerful laser than what you can buy in a laser pointer. I just wanted to pass along the info and a warning to do your research and please be careful should you experiment with lasers. Best regards and good luck! __________________ scrump
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Bill ML Power-User Join Date: Jul 2007 Location: Orlando Posts: 242 Good Answers: 3	#17 Re: Creating a Visible Beam with LED 12/03/2008 1:38 PM
	Bo: (finally?) seems to later better define perhaps what he is wanting to accomplish. There are laser modules in the 5mW range, and yes green, that should do what you are wanting to do, such as ability to focus properly that may give you the result that you are looking for. They are not cheap. I'm not sure why red (less expensive) would not work, but you are the boss. Maybe you need to provide just what it is that you are wanting to do.
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Bill H. Power-User Join Date: May 2007 Location: Hurst, Texas Posts: 178 Good Answers: 4	#18 Re: Creating a Visible Beam with LED 12/03/2008 3:21 PM
	A little baby powder scattered by blown air will make it visible, but gets messy. A fog from a machine or an ultrasonic vaporizer will also work. __________________ Bill H.
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Anonymous Poster	#19 Re: Creating a Visible Beam with LED 12/03/2008 11:03 PM
	Can a conventional LED produce a beam like a LASER diode does? No. You'll never get an LED to collimate in as tight a beam as a LASED diode with a simple optic on the front. The best I've seen to date is something like a 5 degree beam and the lens is 25 mm in dia. (again, nothing resembling a LASER diode) Can you create a beam that is visible in the air (in daylight) like a LASER with a regular LED? I assume you mean like a LASER light show type of beam. Again, no. You can always make the light more visible by shooting it through smoke, fog, or something else to scatter the light toward you eye so you can see it, but I don't think that's what you're looking for either. It sounds like you want a beam that is visible in the regular air, even in daylight. That would be a really powerful beam of light to scatter enough energy off the small amount of dust that's in regular every day air so you can see it in plain daylight. You aren't going to get that kind of power out of an LED, or even a LASER LED. You're going to be talking something that is water cooled (at the least) to do that. If you think a LASER diode is expensive, baby you ain't seen nothing yet... (With apologies to BTO)
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Sciesis2 Guru Join Date: Oct 2006 Location: Vancouver (not BC) Washington (not DC) US of A Posts: 1261 Good Answers: 12	#20 Re: Creating a Visible Beam with LED 12/04/2008 3:10 PM
	Now you all have got me thinking. I wonder how complex it would be to make a laser cutter capable of handling .091 inch sheet aluminum. It might make fabricating electronic product sheet metal much easier than having umpteen punches... dies... etc. Bill
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Anonymous Poster	#22 In reply to #20 Re: Creating a Visible Beam with LED 12/07/2008 12:16 PM
	LASER cutters are already in existence for fabricating metal products. I have a friend who has a couple 4000 Watt Liquid Nitrogen cooled beasties that cut through steel like butter. (they cut great blades for ice skates in seconds...) Incidentally, aluminium is the hardest metal to cut through with one because it is so reflective. They need a special profile loaded into the LASER to prevent damage to it. But they can cut through a half inch of that stuff with ease as well. I'm sure there are lower wattage ones that can handle the job you want to do with them.
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D.RAMAKRISHNA NAIDU Power-User Join Date: Jan 2008 Location: CHENNAI, INDIA Posts: 302 Good Answers: 6	#21 Re: Creating a Visible Beam with LED 12/05/2008 5:39 AM
	*Bo:* *Is it possible to create a visible beam using a LED?* No.LIGHT BY ITSELF IS INVISIBLE.A beam of light will be invisible and only when it is reflected off some object(s), the object(s) become visible.Using an LED or Laser or any other luminescent source will still not give a Visible beam. *Basically I would like to know if a LED can produce a beam like a laser does.* No.Laser output is far more intense (denser) than output from LED for the same wattage. *Would you say that your comment is "off-topic" with respect to the original Forum Thread?* These posts are ok (to a point), but it is considered polite to check this box so that those who want to stay "on-topic" can do so easily. (You may find that your comments will be marked as off-topic by the community anyway, so why not save us all the trouble.) Being direct answers, how can it be considered 'off topic'?? D.Ramakrishna Naidu __________________ Design & Build HOMOPHILIC Suprahuman ROBOTS
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dkwarner Guru Join Date: May 2006 Location: Placerville, CA (38° 45N, 120° 47'W) Posts: 6215 Good Answers: 248	#23 In reply to #21 Re: Creating a Visible Beam with LED 12/07/2008 11:44 PM
	"Being direct answers, how can it be considered 'off topic'??" Unfortunately, the rating dialog box only offers two choices: Good answer, and off topic, so the only choice for one wishing to rate an answer as poor or bad is to select off topic. Perhaps the moderators/programmers of CR4 could remedy this problem... Dick __________________ Teaching is a great experience, but there is no better teacher than experience.
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mircoconsultant Power-User Join Date: Feb 2008 Location: Newmarket, near Toronto, Ontario, Canada Posts: 126 Good Answers: 2	#24 In reply to #23 Re: Creating a Visible Beam with LED 12/14/2008 2:22 PM
	Rating Problem, I agree that the rating system could use some improvements. CR4 - time for some minute evolution! How about a posting and discussion?? Maybe I`ll start one... MG __________________ Mirco
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JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#25 In reply to #24 Re: Creating a Visible Beam with LED 12/14/2008 6:17 PM
	Discussions about the rating system come up every few months - here's one fairly recent one: http://cr4.globalspec.com/thread/20795/Change-Good-Answers-to-Good-Threads, but if you search back, you'll find many more. As far as I can tell, among the various suggestions for changes, nothing has come up as a universally accepted improvement to the current system. I've got my beefs, but so has pretty well anyone on CR4. Best thing to do IMHO is let it drift past - don't fret about it. Not worth losing sleep over. __________________ "Love justice, you who rule the world" - Dante Alighieri
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Sciesis2 Guru Join Date: Oct 2006 Location: Vancouver (not BC) Washington (not DC) US of A Posts: 1261 Good Answers: 12	#26 In reply to #25 Re: Creating a Visible Beam with LED 12/15/2008 8:12 AM
	As an add on... It was not that long ago when we had NO rating system... and considering this is all free, I think we should be thankful for what we have. Bill
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JohnDG Guru Join Date: May 2006 Location: Reading, Berkshire, UK. Going under cover. Posts: 9684 Good Answers: 468	#27 In reply to #26 Re: Creating a Visible Beam with LED 12/15/2008 8:21 AM
	Hear, hear! __________________ "Love justice, you who rule the world" - Dante Alighieri
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bob c

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Join Date: Jul 2007

Location: Fort Lauderdale Florida

Posts: 5708

Good Answers: 123

#28

Re: Creating a Visible Beam with LED

12/15/2008 12:12 PM

I am not sure that I understand exactly what it is that you want. If you want a LED to be as powerful as a laser, Well you have heard the answers already. But if you are looking for a LED powered light that holds a very tightly focused beam of light, and is quite strong, Take a look at this light sold by Grote. I have one mounted on a truck, and have not found any of Hella"s lights that can match the distance and brightness combination.

Trilliant™ LED High Output Work Lamp

PRODUCT NUMBER
63571 - Spot, NEW

FEATURES & BENEFITS

•	Long-lasting, high output LED work lamp
•	Field tested in brutal off-road conditions
•	Beam pattern can be changed with optional replacement lenses
•	Easily mountable with a durable 1/2" stud mounting bracket, also features Aim-N-Go technology
•	Color temperature provides a natural contrast most like sunlight, reducing eye fatigue and optimizing job performance
•	Superior lamp for mining, military, construction, off-road, agriculture, utilities, emergency, and any general illumination for applications that require a durable lamp delivering a long life bright light that is low heat emitting

OTHER PRODUCT NUMBERS
63581 - Flood, NEW
63761 - Wide Flood, NEW
63591 - Trapezoid, NEW
63671 - Spot, 24V, NEW
63681 - Flood, 24V, NEW
63771 - Wide Flood, 24V, NEW
63691 - Trapezoid, 24V, NEW

TECHNICAL SPECIFICATIONS
Material: Powder Coated Steel/Cast Aluminum/ Polycarbonate Lens
Finish: Black
Voltage Amp: 10 - 30 V- 24V - 2.1A
Bracket: 43652
Lens: 94580- Spot & Wide Flood Lens
94600- Flood Lens
94590- Trapezoid Lens

Their site is

www.grote.com Good luck.

__________________
Bob

dkwarner Guru Join Date: May 2006 Location: Placerville, CA (38° 45N, 120° 47'W) Posts: 6215 Good Answers: 248	#29 In reply to #28 Re: Creating a Visible Beam with LED 12/15/2008 1:09 PM
	Thanks for the link! I couldn't be sure whether the ones labeled 24V also work on 12V (I did see 10-30V, but can't tell whether that refers to a range of voltage for a single device, or different devices for different voltages). I also was unable to find any pricing. How much are they? __________________ Teaching is a great experience, but there is no better teacher than experience.
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bob c Guru Join Date: Jul 2007 Location: Fort Lauderdale Florida Posts: 5708 Good Answers: 123	#30 In reply to #29 Re: Creating a Visible Beam with LED 12/15/2008 1:13 PM
	The light will work with anything from 10 to 30 volts. Pricing was about $450. US. It also has interchangeable lenses available to change from spot to trapazoilal to flood. __________________ Bob
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dkwarner Guru Join Date: May 2006 Location: Placerville, CA (38° 45N, 120° 47'W) Posts: 6215 Good Answers: 248	#31 In reply to #30 Re: Creating a Visible Beam with LED 12/15/2008 1:35 PM
	WOW! That puts it out of consideration for most of my needs! Thanks again! __________________ Teaching is a great experience, but there is no better teacher than experience.
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bob c Guru Join Date: Jul 2007 Location: Fort Lauderdale Florida Posts: 5708 Good Answers: 123	#33 In reply to #31 Re: Creating a Visible Beam with LED 12/15/2008 2:05 PM
	In a more affordable light. The Inova company sells a rechargeable LED flashlight called T4 that puts out 175 watts in a spread beam. It will not light a sign a mile away, but still a good light. __________________ Bob
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Bill ML Power-User Join Date: Jul 2007 Location: Orlando Posts: 242 Good Answers: 3	#32 Re: Creating a Visible Beam with LED 12/15/2008 1:49 PM
	Once again, it appears as though an inquirer (Bo) begins with nil information and so many expend their time an energy that are well above their brain caps. Bo has not said just what he wanted to accomplish with his project. That's the first indicator also. In all fairness, the originator really must include these points in order to gain the information they want. On the forgiven side, an inquirer that truly is coming with a school project; but they should iterate just that. They and others don't seem to bother to Google for information, just lean on CR4. CR4 should be maybe the next step in not finding an answer.
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bwire Guru Join Date: Dec 2007 Location: Upper Mid-west USA Posts: 7498 Good Answers: 97	#34 In reply to #32 Re: Creating a Visible Beam with LED 12/15/2008 10:54 PM
	Bo has not said just what he wanted to accomplish with his project. That's the first indicator also. What could it be?? Since an LED will recharge a solar device could it cause heat to be created if focused with a Fresnel lens?? Yes you are correct. A visible beam is useful tool in stage lighting and a "pin spot" is the tool for the job. LED pin spots are on the market. __________________ If death came with a warning there would be a whole lot less of it.
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