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Archive 1 | Archive 2 | Archive 3 | Archive 4 |
Blue LEDs existed before Nakamura's invention. What Nakamura invented was a high-brightness blue LED. In his 1993 patent application (US Patent No. 5,578,839), he refers to several prior publications, the earliest being "Jpn. Pat. Appln. KOKAI Publication No. 64-17484". Here are its details from the Japanese Patent Office website:
This patent describes an LED that emits blue light with a "wavelength of 4800 nm" [sic]. As far as I can tell, all the other publications referred to in Nakamura's patent also relate to blue LEDs. But he goes on to say that "All conventional light-emitting devices are unsatisfactory in both output power and luminance, and have no satisfactory luminosity."
So basically, blue LEDs have been around since the mid 1980s, but Nakamura was the first to develop a practical device. -- Sakurambo 桜ん坊 10:31, 22 January 2007 (UTC)
NOTE: I should probably also point out that the assignee of Nakamura's 1993 patent is Nichia Chemical Industries. If someone from Nichia is trying to claim that highly efficient blue LEDs existed before Nakamura's invention, then this document should put an end to the argument. -- Sakurambo 桜ん坊 11:30, 22 January 2007 (UTC)
WHy so much about the first few years in the intro? The first few patents seems like some quite trivial for the overview...
24.95.50.181 03:33, 24 March 2007 (UTC)
It would be good to have a table of lumens vs. color for various typical current LEDs. This is a product of the efficiency of the devices and the response of the human eye. The article is kind of a hodge-podge collection of exotic info, not so good for typical current info.- 69.87.200.211 10:17, 15 May 2007 (UTC)
This article is currently quite misleading about typical current LED brightness and efficiency. And there is no mention of mcd, which is the most commonly used term for rating ordinary LEDs.- 69.87.203.48 21:10, 19 May 2007 (UTC)
LEDs are getting more and more efficient and in many cases are more efficient than currently used light bulbs. What is misleading?-- Gloriamarie 21:16, 3 August 2007 (UTC)
It is absurd that someone just censored mentioning the traditional buzz of (some) ballasts. WP articles are not advocates of any tech, nor unconcerned with history!- 69.87.203.17 23:28, 27 May 2007 (UTC)
who can show me the white LED I-V curve?? thanks!! —The preceding unsigned comment was added by Ryan siow ( talk • contribs) 08:19, August 22, 2007 (UTC).
I understand that some LEDs can be manufactured that will change color with the applied voltage. Are these commercially available at the moment, and are they practical in terms of expected life, reliability. etc? —Preceding unsigned comment added by 68.162.238.162 ( talk) 02:26, 5 September 2007 (UTC)
This sounds confused. Each LED die will not change colour, however one can put 2 or 3 in a package and vary the supply to each. Tabby ( talk) 06:19, 24 January 2008 (UTC)
I hear LED pronounced like the word 'led' much more often than L-E-D and think 'lead' may be the generally accepted pronunciation. So maybe all the "an LED"s in the article should be changed to "a LED"s. Keep in mind words like 'LASER' and 'SCUBA' before writing off this proposal. The dictionary doesn't make the definitions and pronunciation, it just keeps track of them -- meaning it isn't always up to date. Just check google. "a LED" 224k results. "an LED" is 199k results.—Preceding unsigned comment added by 75.72.206.28 ( talk) 02:56, 11 December 2007 (UTC)
Is it just me or does this display look remarkably like Nixie Tubes?
Some of the layout of the sections don't make much sense. My section numbers are from [1]. Section 1 is the history and then Section 7 is "a" history? Sections 7.x are unrelated to the history, altho 7.2.1 might be related. Yng varr 18:44, 30 January 2008 (UTC)
Seems there are people editing that don't understand the subject, and are drawing numerous oversimlified conclusions from references. The article currently contains an awful lot of misinformation, due I think to misunderstnding material. Personally I'm not interested in editing things that are changed by various folk that lack understanding of the subject material, its just pointless.
Are there any mechanisms in wikipedia to help improve this problem? If not the article will continue to contain a fair amount of misinformation, since its what unqualified people have been told by enthusiastic promoters with $ signs in their eyes. Tabby ( talk) 19:35, 21 February 2008 (UTC)
Meanwhile I think its time to consider changing A class to B class, due to the many errors in an otherwise thorough article. Tabby ( talk) 19:48, 21 February 2008 (UTC)
There were two history sections, one at the beginning and one at the end of the article. I moved the content at the end toward the beginning, but there are some points of redundancy that an expert on this article should try to remove: for example, Losev's invention is mentioned twice. Shalom ( Hello • Peace) 15:21, 10 March 2008 (UTC)
Removed this sentence: In early 2008, researchers at Bilkent University in Turkey demonstrated a new technique for producing white light from blue LEDs coated with nanocrystals. This approach was shown giving off "more than 300 lumens per watt". [1]
This is about visible lumens per watt of emitted light, not about lumens of visible light per electrical watt, as the others, and therefore not comparable. -- 87.187.10.235 ( talk) 18:25, 8 April 2008 (UTC)
and quite frankly I'm not sure if every single new piece of research belongs on Wikipedia. Unless someone comes along and edits it for style, I'm deleting it. eigenlambda ( talk) 18:51, 8 April 2008 (UTC)
Is it just me, or is the first paragraph of the lead a tad overly-technical? Things like that belong in the article, of course, but the first paragraph of the lead should probably have more of a layman's description, useful for people with no background in the subject. The second paragraph of the lead seems to work quite well for this; I'm just wondering if it's good to have such a technically-oriented paragraph before it. Maybe they should just be swapped. -- Aquillion ( talk) 03:02, 29 April 2008 (UTC)
I agree, a simple explanation at the top would be great. —Preceding unsigned comment added by 84.216.47.83 ( talk) 19:21, 17 May 2008 (UTC)
This development. Kaiwhakahaere ( talk) 20:17, 8 May 2008 (UTC)
http://en.wikipedia.org/wiki/Haitz's_Law ( talk) June 20 2008 -- Reachtokaushik ( talk) 09:46, 20 June 2008 (UTC)
There is a lot of good information in this article but is also has many problems:
There is a big paragraph/section on the history _before_ the discovery subsection which actually only has a small part about the discovery. A subsection of the history is about LED panels (should maybe be under applications). Then, very prominently there is a subsection about touch sensing with a reference to one paper and no examples of applications (how relevant is this?).
In the "physical function" subsection semiconductor physics is mixed with light extraction and after that a long list of materials that relate back to the semiconductor part.
The White LEDs section is a small article in itself that actually starts by talking about RGB systems that are in fact NOT white LEDs. The section (in my view) lacks organization and subsection. Maybe it should be its own article since the white LEDs are becoming so important.
The diagram in the OLED section have nothing to do with OLED, and why is "potential of OLED"s a subsection of "Efficiency and operational parameters"
There is a huge amount of information in this article but it seems to have been arranged with at shovel. If someone could explain the reasoning behind these "issues" I would be most grateful if not I will get to work on them since this is a subject I care a lot about.
-- Thorseth ( talk) 02:35, 4 July 2008 (UTC)
White (light) LEDs are becoming increasingly important, but the section is lacking in many ways so i suggest it gets moved to its own article. —Preceding unsigned comment added by Thorseth ( talk • contribs) 14:05, 4 July 2008 (UTC)
Sorry that I forgot -- Thorseth ( talk) 12:07, 5 July 2008 (UTC)
I think the White led section should be cut in two "RGB systems" and "Phosphor coating"(or something) that could very well be much shorter. I also think that LED lamp is a very broad article that does not adress the issue of white light generation very much. -- Thorseth ( talk) 12:24, 5 July 2008 (UTC)
I just bought some pink-magenta LEDs and it has a phosphor coating. I don't think the section on phosphor LEDs should be limited to white. Ginbot86 ( talk) 20:25, 18 July 2008 (UTC)
This is a very long section on a single use of LEDs that says more about sinage and not so much about LEDs. If all the possible applications of LEDs had similar treatment the LED article would several MB in size.-- Thorseth ( talk) 13:15, 29 July 2008 (UTC)
I just grabbed this table from the french wikipedia. I like how it relates color, material, voltage and wavelength. I just translated it and have not checked it for facts. It could replace the material section and the "voltage-color" table under "considerations". Any objections?
-- Thorseth ( talk) 11:32, 14 August 2008 (UTC)
I recently took a science course in which one of the lessons involved dipping LEDs of various colors into liquid nitrogen to cool them. This caused the wavelength of the emitted light to shift towards the blue end of the electromagnetic spectrum (i.e. the yellow LED turned green, the green LED turned blue, etc.). This had something to do with band gap energy or something. Should this be mentioned in the article? Ilikefood ( talk) 18:19, 29 August 2008 (UTC)
I really like Wikipedia as a news source and have a 'latest discovery' that I think should be added:
http://news.uns.purdue.edu/x/2008b/080717SandsLighting.html |Title=Advance brings low-cost, bright LED lighting closer to reality | Publisher=Purdue University
I believe that when applied, this possible reduced cost manufacturing process will have a profound impact on the enlarged use of LEDs for many lighting purposes, even though a time line for practical use has not been established. LED manufacturing, like all electronic device manufacturing, uses many toxic materials, but LEDs have less harmful materials contained within than say CCFLs and their mercury concerns.
I think more of these types of items could be included in Wikipedia as soon as published, for reference at least. Walrus Webtech ( talk) 05:20, 1 September 2008 (UTC)
I have a comment to make about the table. I noticed that InGaN and GaN are both listed in the Green category. However, they are not the same shade of green as the others listed, they are a shade known as Pure Green or Emerald Green. I personally think that Pure Green should be listed separately from the other Green LEDs, not simply because they are a different shade, but they are considered a distinct category from traditional green LEDs. If anyone knows the difference in wavelenghts between Green and Pure Green, please post it here. ANDROS1337 02:29, 16 October 2008 (UTC)
At the University of Cincinnati the DNA in salmon sperm has recently been discovered to amplify the effects and quality of an LED light [2] [3].
Which type of LED technology does Laptops with LED screens most commonly use? Blue LED, White LED or Colored LED. I am a bit confused about the different types of LED's.
Netbooks like the ASUS EEE PC and the Acer Aspire One, which type of technology do they use - do they just use white LED to light up the screen?
And do LED notebook screens pose a health hazzard if they are white LED or Blue LED? ("Blue Hazzard")? —mesmerator
To answer all three of your questions:
Ok, my rather rash edits was reverted, so ill put my suggestion up here and see what happens. The subsection "Christmas light" under the section "Considerations for use" is, I think, misplaced and unnecessarily long. Non of the other niche applications are given more than a line or two. However I think that the application is interesting enough to be put in a separate article. Any objections or suggestions?
-- Thorseth ( talk) 15:12, 3 January 2009 (UTC)
Please revise the lead to use some simpler terminology. 'p-n Junction' could instead say "junction of two different semiconductors, or 'p-n junction' ". Use of some dependent clauses to explain the rather technical terminology would be better. I had to reaad four articles to understand one lead, and that's not how a wikipedia article should go. I get the basic idea now, electricity goes into the element, light comes out, but it took way too much effort to have to learn that. ThuranX ( talk) 00:01, 5 January 2009 (UTC)
A light-emitting-diode (LED) /ˌɛliːˈdiː/, [3] is a semiconductor component, of the diode type, that emits light when an electric current is supplied in the forward direction of the diode. The effect is a form of electroluminescence where electrical energy is converted to light when electrons and electron holes are joined in the junction between a two semiconductor materials ( p-n junction). The light is incoherent and narrow- spectrum.
The user User_talk:WikiEditorContributor has copy-pasted material from industri news web sites
please compare
and
The material is unreferenced and almost a direct copy. Can someone please take the nessesery steps as I don't have time-- Thorseth ( talk) 09:28, 12 January 2009 (UTC)
Maybe this section can be inserted somewhere else?, rather than being lost. Electron9 ( talk) 14:09, 12 January 2009 (UTC)
xxxxxxxxxxxxxxx
Most LED Christmas lights (at least in 120-volt North America) are operated directly from mains electricity, with an in-line resistor (molded inside a small cylinder the same green or white color as the wire insulation) for each circuit. Older colors are operated in circuits of up to 60 LEDs, while newer or mixed colors are normally in one or two circuits of 25, 30, or 35. An example of Halloween lights is two different sets of 70 LEDs: the orange set is divded into two circuits with a one-kilo ohm resistor each, while the purple (blue with red phosphor) set is three circuits with a 1.1 kΩ resistor each. Each circuit uses 2.4 watts, and from this it is derived that the LEDs are about 5 kΩ in total.
he alternating current can be seen in these sets by spinning one end of the string around. It is then apparent that the LEDs are on less than half of the time, being off when the voltage is negative (reverse-biased) or too low. The slightly-delayed rise and slow decay of phosphors can also be seen in each flash, depending on their phosphorescence. While inexpensive, the flickering caused by this method can be annoying to some people. Additionally, the unsmoothed peak voltage of nearly 170 total volts in each cycle shortens the life of the LEDs, though they are still rated for a service life ( MTTF) of around 25 000 hours (if moisture does not rust them first). However, blue and deep-green ones are more prone to failure, especially early in their use.
I'm concerned about the following paragraph:
Cree issued a press release on November 19th, 2008 about a laboratory prototype LED achieving 161 lumens/watt at 350 mA (Over 10 times more efficient than incandescent lightbulbs). Output was 173 lumens. Power works out to 1.075 watts. Voltage drop works out to 3.07 volts. citation needed original research? Correlated color temperature was reported to be 4689 K. [4]
LED manufacturers and researchers tend to quote luminous efficacy of radiation (LER), rather than the overall ("wallplug") luminous efficacy of their devices. [5] This gives numbers that are larger than the overall efficacy, which is undoubtedly convenient for marketing, irrespective of any technical justification for its use. The cited press release does not give sufficient information to establish that the value cited is overall luminous efficacy, not LER. The paragraph above, however, gives a value for the voltage which is not given in the press release. If this were a true value, it would support the conclusion that the LE value given is wallplug luminous efficacy not LER. From the wording, however, I suspect that this uncited voltage was calculated by a Wikipedia editor from the values of luminous efficacy and current, assuming without justification that the efficacy given is the wallplug value. Besides being wrong, this is original research.
Finally, note that manufacturer's press releases are not reliable sources. They can be used as sources for Wikipedia articles only when they meet certain conditions, including that the information not be self-serving. Inflated luminous efficacy figures probably count as self-serving.
I am removing the sentences that are uncited and probably original research. I suggest that editors of this article delete the entire paragraph until it can be confirmed by a reliable source.-- Srleffler ( talk) 05:15, 13 January 2009 (UTC)
For me this section looks like advertising and it should be removed. If nobody objects Ill do it within this week-- Thorseth ( talk) 14:01, 15 January 2009 (UTC)
I will try to get the article ready for Wikipedia:Peer_review which means getting rid of all major clean up banners. The objective is of cause to get to featured article ( WP:FA) status at some point.-- Thorseth ( talk) 14:31, 15 January 2009 (UTC)
A LED flashlight uses a small plano-convex lens to create a beam from the light generated by the white LED. I have these type of lights. Powerzilla ( talk) 21:01, 21 January 2009 (UTC)
I would like to know what you think of this new longer lead. Its missing all the wikilinks and references and perhaps some punctuation, but the general idea should be there.
What do you think? -- Thorseth ( talk) 10:23, 13 February 2009 (UTC)
I'm not usually one to argue over international conventions, or just dig in and fix them, but I think we need to fix this one:
Many of the LEDs produced in the 1970s and 1980s are still in service today. Typical lifetimes quoted are 25.000 to 100.000 hours but heat and current settings can extend or shorten this time significantly.
It means something different than intended in the locality of the rest of the article. Should this be fixed? -- Steven Fisher ( talk) 19:07, 20 February 2009 (UTC)
Flashing LEDs, Bi-color LEDs, Tri-color LED, RGB LEDs, 'Alphanumeric LED displays all is not custom design, these are just specific application in general for any user.-- Namazu-tron ( talk) 11:22, 22 February 2009 (UTC)
Please state a reputable source for changing the discoverer/inventor of the LED from HJ Round to Loslev. He was not first and stating "mid 1920" as the time of discovery/invention is not very precise or encyclopedic. If someone other than Round should be the inventor it should be Holonyak who made a usable LED as we know it today. This is a huge thing to change without discussion.-- Thorseth ( talk) 10:08, 23 February 2009 (UTC)
This is a list of 70 articles [6] that references Rounds work. I have not been able to find one reference other than Zhelduv, Nat. Photonics (2007), to the Loslev articles published almost ten years after. -- Thorseth ( talk) 10:51, 23 February 2009 (UTC)
light emit/light emits (first section) —Preceding unsigned comment added by 67.233.167.196 ( talk) 14:39, 15 February 2009 (UTC)
I am not a native English speaker, so I am wondering what the correct form is. Is it "a LED" or "an LED" and if both when, is it the one and when is it the other. Both occur in the article.-- Thorseth ( talk) 12:58, 24 February 2009 (UTC)
By using a major web search engine whose name rhymes with "frugal", I found an absurd number of Wikipedia articles on various aspects of the light-emitting diode. I added them all to the LED_(disambiguation) page, on the theory that if they're here they should be referenced. However, my goal is to seriously reduce the number of articles, by merging them or even just deleting them. I'm posting here to get people's reaction before I start wielding my machete.
Here's the list of pages I found, with my own notes and opinions in parenthesis:
So, I'd reduce this whole shebang to the following: Light-emitting diode, Organic light-emitting diode, LED circuit, LED physics, LED lighting, LED beacons, LED art, LED products. That's merging 23 articles down to 8.
Reactions? Am I too deletionist, or perhaps not even enough so? -- Dan Griscom ( talk) 22:58, 2 March 2009 (UTC)
I think the suggestions are good, the LED physics is much needed. LED still has a lot of very detailed information (blue and UV, white light), while the solid state physics aspect is only loosely covered. A physics article should have all these details. I have made some of the splits, to make LED more readable without loosing content, but merging these small articles together in something like LED circuit and LED physics is a good idea. I wonder if LED lamp and LED circuit does not really belong together in some way, there seems to be missing something like a LED system or LED lamp, from wall plug to illumination sort of thing, combining "circuit", "heat management", LED optics etc. It nice to see a lot people working to improve on the subject.-- Thorseth ( talk) 09:31, 3 March 2009 (UTC)
Here's my consolidated list again (plus one new article), with my reasonings added. Note that I'm not drawing a line in the sand; I'm just elucidating my reasoning. The list of nine articles:
I'm open to further consolidation if there's consensus. However, cutting the 23 articles down to 3 (plus material placed in other articles) is more than I'd like. -- Dan Griscom ( talk) 23:34, 3 March 2009 (UTC)
Well, I guess I'd better get going on this. For my own reference (and in case anyone else wants to dig in), here's my current thinking on the final article list:
I'm least certain of the LED products page. I was thinking to gather together a set of LED-based products that (for the most part) don't really deserve their own articles. I'm no longer sure this is a useful path, though; perhaps these articles should just be improved in-place (or nominated for deletion). Thoughts? -- Dan Griscom ( talk) 03:01, 8 March 2009 (UTC)
"LED Display" I agree that it is under a broad catagory. Seems graphics displays (e.g. signage or generally static billboards) are one technology / product item and video/tv displays are another. I believe the industry is just getting started with video displays (e.g. Samsung's LCD/LED hybrid model)and we have stadium video. I can see separating graphics apps from the video perhaps. What grouping does LED technology history belonge ? - Jim April 25
I suggest that LED TV (LED backlight LCD display) should be merged with LCD TV and not included with the LED articles. With OLED displays included in the LED display section. —Preceding unsigned comment added by 86.172.177.145 ( talk) 07:59, 7 May 2009 (UTC)
—Preceding unsigned comment added by 71.221.240.156 ( talk) 01:21, 26 April 2009 (UTC)
Exploring this thicket of inter-related articles, I am mostly glad so far for the diversity. If they were well-organized and merged, people would start coming along and deciding the resulting mega-articles had "too much unneeded detail" and "simplifying". As things are, many of the articles are stubs, yearning to be fleshed out, which seems better. In conclusion, if you see two smallish articles that seem like a natural match, merging might be fine, but please don't merge something small into something big... - 71.174.180.243 ( talk) 03:05, 16 June 2009 (UTC)
Merge at least some I at least think that the various articles on general illumination with LEDs should get consolidated. This area is changing rapidly and it will make it easier to keep them all up to date. Ccrrccrr ( talk) 04:40, 19 June 2009 (UTC)
Perhaps the design diagrams (low-power and high power leds) from following article can be taken over: http://www.elektor.com/magazines/2008/february/power-to-the-leds.350167.lynkx
Also, the diagram of a common LED should be integrated (consists of die, lens, cooling body and connection wires)
Also, It should be added in the article that red, amber, and orange LEDs are made of AlInGaP (aluminum, indium, gallium, phosphor) green, blue, and cyan LEDs are made of InGaN (indium, gallium, and nitrogen)
The CANbus system should also be mentioned as an open-source solution to power lighting LED's in dwellings. See http://www.elektor.com/magazines/2008/february/the-ledbus-system.350139.lynkx (it allows installation of regular leds instead of led lamps with imbedded electronics)
Thanks,
81.246.131.67 ( talk) 08:11, 6 March 2009 (UTC)
I'm a little disappointed that Torseth removed my image. LEDs are becoming more common in car lighting and a typical way to see a car has LEDs is to see them blink while they drive by, or move your eyes across them. I caught a car with blinking LEDs with a camera and thought, this might be interesting here. It also illustrates nicely, how quickly LEDs can be turned on and off, which is also mentioned in the article. But true, you don't see much of it on the thumbnail.
I wonder, if there are combined back-/brake lights, where the backlight function is with PWM while the brakelight is with full duty cycle. But maybe these lights are required to be separate.
Nevertheless, thanks for your work on this article, Torseth. Darsie from german wiki pedia ( talk) 12:59, 19 March 2009 (UTC)
"While not an LED as such, an ordinary NPN bipolar transistor will emit violet light if its emitter-base junction is subjected to non-destructive reverse breakdown. This is easy to demonstrate by filing the top off a metal-can transistor (BC107, 2N2222 or similar) and biasing it well above emitter-base breakdown (≥ 20 V) via a current-limiting resistor."
Apart from being about NPN technology rather than LED this is unintelligible to me as a non-specialist -- AndyCPrivate ( talk) 13:44, 12 May 2009 (UTC)
Well I would guess that you create some hole/electron pairs in what is effectively a PN junction that recombine at "zero-k" in the band gap, if the material is germanium for instance this is quite natural, for silicon I don't know... -- Thorseth ( talk) 23:40, 13 May 2009 (UTC)
Please add data about the biggest LED makers, how much they make per year, where the LEDs are actually made, and whether the parts are actually made by them, or made by others for them.
What hazards and pollution are associated with manufacture? Where has this had the most impact? - 96.237.10.106 ( talk) 12:48, 3 June 2009 (UTC)
I removed the statement that LEDs would result in 50X less waste compared to incandescents. Heft a high power LED screw-in replacement, with its Al heatsinks, etc. Then feel how light an incandescent bulb. Next consider that glass is a lot less energy intensive to produce than aluminum. That statement was not justified. Ccrrccrr ( talk) 04:36, 19 June 2009 (UTC)
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This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 | Archive 2 | Archive 3 | Archive 4 |
Blue LEDs existed before Nakamura's invention. What Nakamura invented was a high-brightness blue LED. In his 1993 patent application (US Patent No. 5,578,839), he refers to several prior publications, the earliest being "Jpn. Pat. Appln. KOKAI Publication No. 64-17484". Here are its details from the Japanese Patent Office website:
This patent describes an LED that emits blue light with a "wavelength of 4800 nm" [sic]. As far as I can tell, all the other publications referred to in Nakamura's patent also relate to blue LEDs. But he goes on to say that "All conventional light-emitting devices are unsatisfactory in both output power and luminance, and have no satisfactory luminosity."
So basically, blue LEDs have been around since the mid 1980s, but Nakamura was the first to develop a practical device. -- Sakurambo 桜ん坊 10:31, 22 January 2007 (UTC)
NOTE: I should probably also point out that the assignee of Nakamura's 1993 patent is Nichia Chemical Industries. If someone from Nichia is trying to claim that highly efficient blue LEDs existed before Nakamura's invention, then this document should put an end to the argument. -- Sakurambo 桜ん坊 11:30, 22 January 2007 (UTC)
WHy so much about the first few years in the intro? The first few patents seems like some quite trivial for the overview...
24.95.50.181 03:33, 24 March 2007 (UTC)
It would be good to have a table of lumens vs. color for various typical current LEDs. This is a product of the efficiency of the devices and the response of the human eye. The article is kind of a hodge-podge collection of exotic info, not so good for typical current info.- 69.87.200.211 10:17, 15 May 2007 (UTC)
This article is currently quite misleading about typical current LED brightness and efficiency. And there is no mention of mcd, which is the most commonly used term for rating ordinary LEDs.- 69.87.203.48 21:10, 19 May 2007 (UTC)
LEDs are getting more and more efficient and in many cases are more efficient than currently used light bulbs. What is misleading?-- Gloriamarie 21:16, 3 August 2007 (UTC)
It is absurd that someone just censored mentioning the traditional buzz of (some) ballasts. WP articles are not advocates of any tech, nor unconcerned with history!- 69.87.203.17 23:28, 27 May 2007 (UTC)
who can show me the white LED I-V curve?? thanks!! —The preceding unsigned comment was added by Ryan siow ( talk • contribs) 08:19, August 22, 2007 (UTC).
I understand that some LEDs can be manufactured that will change color with the applied voltage. Are these commercially available at the moment, and are they practical in terms of expected life, reliability. etc? —Preceding unsigned comment added by 68.162.238.162 ( talk) 02:26, 5 September 2007 (UTC)
This sounds confused. Each LED die will not change colour, however one can put 2 or 3 in a package and vary the supply to each. Tabby ( talk) 06:19, 24 January 2008 (UTC)
I hear LED pronounced like the word 'led' much more often than L-E-D and think 'lead' may be the generally accepted pronunciation. So maybe all the "an LED"s in the article should be changed to "a LED"s. Keep in mind words like 'LASER' and 'SCUBA' before writing off this proposal. The dictionary doesn't make the definitions and pronunciation, it just keeps track of them -- meaning it isn't always up to date. Just check google. "a LED" 224k results. "an LED" is 199k results.—Preceding unsigned comment added by 75.72.206.28 ( talk) 02:56, 11 December 2007 (UTC)
Is it just me or does this display look remarkably like Nixie Tubes?
Some of the layout of the sections don't make much sense. My section numbers are from [1]. Section 1 is the history and then Section 7 is "a" history? Sections 7.x are unrelated to the history, altho 7.2.1 might be related. Yng varr 18:44, 30 January 2008 (UTC)
Seems there are people editing that don't understand the subject, and are drawing numerous oversimlified conclusions from references. The article currently contains an awful lot of misinformation, due I think to misunderstnding material. Personally I'm not interested in editing things that are changed by various folk that lack understanding of the subject material, its just pointless.
Are there any mechanisms in wikipedia to help improve this problem? If not the article will continue to contain a fair amount of misinformation, since its what unqualified people have been told by enthusiastic promoters with $ signs in their eyes. Tabby ( talk) 19:35, 21 February 2008 (UTC)
Meanwhile I think its time to consider changing A class to B class, due to the many errors in an otherwise thorough article. Tabby ( talk) 19:48, 21 February 2008 (UTC)
There were two history sections, one at the beginning and one at the end of the article. I moved the content at the end toward the beginning, but there are some points of redundancy that an expert on this article should try to remove: for example, Losev's invention is mentioned twice. Shalom ( Hello • Peace) 15:21, 10 March 2008 (UTC)
Removed this sentence: In early 2008, researchers at Bilkent University in Turkey demonstrated a new technique for producing white light from blue LEDs coated with nanocrystals. This approach was shown giving off "more than 300 lumens per watt". [1]
This is about visible lumens per watt of emitted light, not about lumens of visible light per electrical watt, as the others, and therefore not comparable. -- 87.187.10.235 ( talk) 18:25, 8 April 2008 (UTC)
and quite frankly I'm not sure if every single new piece of research belongs on Wikipedia. Unless someone comes along and edits it for style, I'm deleting it. eigenlambda ( talk) 18:51, 8 April 2008 (UTC)
Is it just me, or is the first paragraph of the lead a tad overly-technical? Things like that belong in the article, of course, but the first paragraph of the lead should probably have more of a layman's description, useful for people with no background in the subject. The second paragraph of the lead seems to work quite well for this; I'm just wondering if it's good to have such a technically-oriented paragraph before it. Maybe they should just be swapped. -- Aquillion ( talk) 03:02, 29 April 2008 (UTC)
I agree, a simple explanation at the top would be great. —Preceding unsigned comment added by 84.216.47.83 ( talk) 19:21, 17 May 2008 (UTC)
This development. Kaiwhakahaere ( talk) 20:17, 8 May 2008 (UTC)
http://en.wikipedia.org/wiki/Haitz's_Law ( talk) June 20 2008 -- Reachtokaushik ( talk) 09:46, 20 June 2008 (UTC)
There is a lot of good information in this article but is also has many problems:
There is a big paragraph/section on the history _before_ the discovery subsection which actually only has a small part about the discovery. A subsection of the history is about LED panels (should maybe be under applications). Then, very prominently there is a subsection about touch sensing with a reference to one paper and no examples of applications (how relevant is this?).
In the "physical function" subsection semiconductor physics is mixed with light extraction and after that a long list of materials that relate back to the semiconductor part.
The White LEDs section is a small article in itself that actually starts by talking about RGB systems that are in fact NOT white LEDs. The section (in my view) lacks organization and subsection. Maybe it should be its own article since the white LEDs are becoming so important.
The diagram in the OLED section have nothing to do with OLED, and why is "potential of OLED"s a subsection of "Efficiency and operational parameters"
There is a huge amount of information in this article but it seems to have been arranged with at shovel. If someone could explain the reasoning behind these "issues" I would be most grateful if not I will get to work on them since this is a subject I care a lot about.
-- Thorseth ( talk) 02:35, 4 July 2008 (UTC)
White (light) LEDs are becoming increasingly important, but the section is lacking in many ways so i suggest it gets moved to its own article. —Preceding unsigned comment added by Thorseth ( talk • contribs) 14:05, 4 July 2008 (UTC)
Sorry that I forgot -- Thorseth ( talk) 12:07, 5 July 2008 (UTC)
I think the White led section should be cut in two "RGB systems" and "Phosphor coating"(or something) that could very well be much shorter. I also think that LED lamp is a very broad article that does not adress the issue of white light generation very much. -- Thorseth ( talk) 12:24, 5 July 2008 (UTC)
I just bought some pink-magenta LEDs and it has a phosphor coating. I don't think the section on phosphor LEDs should be limited to white. Ginbot86 ( talk) 20:25, 18 July 2008 (UTC)
This is a very long section on a single use of LEDs that says more about sinage and not so much about LEDs. If all the possible applications of LEDs had similar treatment the LED article would several MB in size.-- Thorseth ( talk) 13:15, 29 July 2008 (UTC)
I just grabbed this table from the french wikipedia. I like how it relates color, material, voltage and wavelength. I just translated it and have not checked it for facts. It could replace the material section and the "voltage-color" table under "considerations". Any objections?
-- Thorseth ( talk) 11:32, 14 August 2008 (UTC)
I recently took a science course in which one of the lessons involved dipping LEDs of various colors into liquid nitrogen to cool them. This caused the wavelength of the emitted light to shift towards the blue end of the electromagnetic spectrum (i.e. the yellow LED turned green, the green LED turned blue, etc.). This had something to do with band gap energy or something. Should this be mentioned in the article? Ilikefood ( talk) 18:19, 29 August 2008 (UTC)
I really like Wikipedia as a news source and have a 'latest discovery' that I think should be added:
http://news.uns.purdue.edu/x/2008b/080717SandsLighting.html |Title=Advance brings low-cost, bright LED lighting closer to reality | Publisher=Purdue University
I believe that when applied, this possible reduced cost manufacturing process will have a profound impact on the enlarged use of LEDs for many lighting purposes, even though a time line for practical use has not been established. LED manufacturing, like all electronic device manufacturing, uses many toxic materials, but LEDs have less harmful materials contained within than say CCFLs and their mercury concerns.
I think more of these types of items could be included in Wikipedia as soon as published, for reference at least. Walrus Webtech ( talk) 05:20, 1 September 2008 (UTC)
I have a comment to make about the table. I noticed that InGaN and GaN are both listed in the Green category. However, they are not the same shade of green as the others listed, they are a shade known as Pure Green or Emerald Green. I personally think that Pure Green should be listed separately from the other Green LEDs, not simply because they are a different shade, but they are considered a distinct category from traditional green LEDs. If anyone knows the difference in wavelenghts between Green and Pure Green, please post it here. ANDROS1337 02:29, 16 October 2008 (UTC)
At the University of Cincinnati the DNA in salmon sperm has recently been discovered to amplify the effects and quality of an LED light [2] [3].
Which type of LED technology does Laptops with LED screens most commonly use? Blue LED, White LED or Colored LED. I am a bit confused about the different types of LED's.
Netbooks like the ASUS EEE PC and the Acer Aspire One, which type of technology do they use - do they just use white LED to light up the screen?
And do LED notebook screens pose a health hazzard if they are white LED or Blue LED? ("Blue Hazzard")? —mesmerator
To answer all three of your questions:
Ok, my rather rash edits was reverted, so ill put my suggestion up here and see what happens. The subsection "Christmas light" under the section "Considerations for use" is, I think, misplaced and unnecessarily long. Non of the other niche applications are given more than a line or two. However I think that the application is interesting enough to be put in a separate article. Any objections or suggestions?
-- Thorseth ( talk) 15:12, 3 January 2009 (UTC)
Please revise the lead to use some simpler terminology. 'p-n Junction' could instead say "junction of two different semiconductors, or 'p-n junction' ". Use of some dependent clauses to explain the rather technical terminology would be better. I had to reaad four articles to understand one lead, and that's not how a wikipedia article should go. I get the basic idea now, electricity goes into the element, light comes out, but it took way too much effort to have to learn that. ThuranX ( talk) 00:01, 5 January 2009 (UTC)
A light-emitting-diode (LED) /ˌɛliːˈdiː/, [3] is a semiconductor component, of the diode type, that emits light when an electric current is supplied in the forward direction of the diode. The effect is a form of electroluminescence where electrical energy is converted to light when electrons and electron holes are joined in the junction between a two semiconductor materials ( p-n junction). The light is incoherent and narrow- spectrum.
The user User_talk:WikiEditorContributor has copy-pasted material from industri news web sites
please compare
and
The material is unreferenced and almost a direct copy. Can someone please take the nessesery steps as I don't have time-- Thorseth ( talk) 09:28, 12 January 2009 (UTC)
Maybe this section can be inserted somewhere else?, rather than being lost. Electron9 ( talk) 14:09, 12 January 2009 (UTC)
xxxxxxxxxxxxxxx
Most LED Christmas lights (at least in 120-volt North America) are operated directly from mains electricity, with an in-line resistor (molded inside a small cylinder the same green or white color as the wire insulation) for each circuit. Older colors are operated in circuits of up to 60 LEDs, while newer or mixed colors are normally in one or two circuits of 25, 30, or 35. An example of Halloween lights is two different sets of 70 LEDs: the orange set is divded into two circuits with a one-kilo ohm resistor each, while the purple (blue with red phosphor) set is three circuits with a 1.1 kΩ resistor each. Each circuit uses 2.4 watts, and from this it is derived that the LEDs are about 5 kΩ in total.
he alternating current can be seen in these sets by spinning one end of the string around. It is then apparent that the LEDs are on less than half of the time, being off when the voltage is negative (reverse-biased) or too low. The slightly-delayed rise and slow decay of phosphors can also be seen in each flash, depending on their phosphorescence. While inexpensive, the flickering caused by this method can be annoying to some people. Additionally, the unsmoothed peak voltage of nearly 170 total volts in each cycle shortens the life of the LEDs, though they are still rated for a service life ( MTTF) of around 25 000 hours (if moisture does not rust them first). However, blue and deep-green ones are more prone to failure, especially early in their use.
I'm concerned about the following paragraph:
Cree issued a press release on November 19th, 2008 about a laboratory prototype LED achieving 161 lumens/watt at 350 mA (Over 10 times more efficient than incandescent lightbulbs). Output was 173 lumens. Power works out to 1.075 watts. Voltage drop works out to 3.07 volts. citation needed original research? Correlated color temperature was reported to be 4689 K. [4]
LED manufacturers and researchers tend to quote luminous efficacy of radiation (LER), rather than the overall ("wallplug") luminous efficacy of their devices. [5] This gives numbers that are larger than the overall efficacy, which is undoubtedly convenient for marketing, irrespective of any technical justification for its use. The cited press release does not give sufficient information to establish that the value cited is overall luminous efficacy, not LER. The paragraph above, however, gives a value for the voltage which is not given in the press release. If this were a true value, it would support the conclusion that the LE value given is wallplug luminous efficacy not LER. From the wording, however, I suspect that this uncited voltage was calculated by a Wikipedia editor from the values of luminous efficacy and current, assuming without justification that the efficacy given is the wallplug value. Besides being wrong, this is original research.
Finally, note that manufacturer's press releases are not reliable sources. They can be used as sources for Wikipedia articles only when they meet certain conditions, including that the information not be self-serving. Inflated luminous efficacy figures probably count as self-serving.
I am removing the sentences that are uncited and probably original research. I suggest that editors of this article delete the entire paragraph until it can be confirmed by a reliable source.-- Srleffler ( talk) 05:15, 13 January 2009 (UTC)
For me this section looks like advertising and it should be removed. If nobody objects Ill do it within this week-- Thorseth ( talk) 14:01, 15 January 2009 (UTC)
I will try to get the article ready for Wikipedia:Peer_review which means getting rid of all major clean up banners. The objective is of cause to get to featured article ( WP:FA) status at some point.-- Thorseth ( talk) 14:31, 15 January 2009 (UTC)
A LED flashlight uses a small plano-convex lens to create a beam from the light generated by the white LED. I have these type of lights. Powerzilla ( talk) 21:01, 21 January 2009 (UTC)
I would like to know what you think of this new longer lead. Its missing all the wikilinks and references and perhaps some punctuation, but the general idea should be there.
What do you think? -- Thorseth ( talk) 10:23, 13 February 2009 (UTC)
I'm not usually one to argue over international conventions, or just dig in and fix them, but I think we need to fix this one:
Many of the LEDs produced in the 1970s and 1980s are still in service today. Typical lifetimes quoted are 25.000 to 100.000 hours but heat and current settings can extend or shorten this time significantly.
It means something different than intended in the locality of the rest of the article. Should this be fixed? -- Steven Fisher ( talk) 19:07, 20 February 2009 (UTC)
Flashing LEDs, Bi-color LEDs, Tri-color LED, RGB LEDs, 'Alphanumeric LED displays all is not custom design, these are just specific application in general for any user.-- Namazu-tron ( talk) 11:22, 22 February 2009 (UTC)
Please state a reputable source for changing the discoverer/inventor of the LED from HJ Round to Loslev. He was not first and stating "mid 1920" as the time of discovery/invention is not very precise or encyclopedic. If someone other than Round should be the inventor it should be Holonyak who made a usable LED as we know it today. This is a huge thing to change without discussion.-- Thorseth ( talk) 10:08, 23 February 2009 (UTC)
This is a list of 70 articles [6] that references Rounds work. I have not been able to find one reference other than Zhelduv, Nat. Photonics (2007), to the Loslev articles published almost ten years after. -- Thorseth ( talk) 10:51, 23 February 2009 (UTC)
light emit/light emits (first section) —Preceding unsigned comment added by 67.233.167.196 ( talk) 14:39, 15 February 2009 (UTC)
I am not a native English speaker, so I am wondering what the correct form is. Is it "a LED" or "an LED" and if both when, is it the one and when is it the other. Both occur in the article.-- Thorseth ( talk) 12:58, 24 February 2009 (UTC)
By using a major web search engine whose name rhymes with "frugal", I found an absurd number of Wikipedia articles on various aspects of the light-emitting diode. I added them all to the LED_(disambiguation) page, on the theory that if they're here they should be referenced. However, my goal is to seriously reduce the number of articles, by merging them or even just deleting them. I'm posting here to get people's reaction before I start wielding my machete.
Here's the list of pages I found, with my own notes and opinions in parenthesis:
So, I'd reduce this whole shebang to the following: Light-emitting diode, Organic light-emitting diode, LED circuit, LED physics, LED lighting, LED beacons, LED art, LED products. That's merging 23 articles down to 8.
Reactions? Am I too deletionist, or perhaps not even enough so? -- Dan Griscom ( talk) 22:58, 2 March 2009 (UTC)
I think the suggestions are good, the LED physics is much needed. LED still has a lot of very detailed information (blue and UV, white light), while the solid state physics aspect is only loosely covered. A physics article should have all these details. I have made some of the splits, to make LED more readable without loosing content, but merging these small articles together in something like LED circuit and LED physics is a good idea. I wonder if LED lamp and LED circuit does not really belong together in some way, there seems to be missing something like a LED system or LED lamp, from wall plug to illumination sort of thing, combining "circuit", "heat management", LED optics etc. It nice to see a lot people working to improve on the subject.-- Thorseth ( talk) 09:31, 3 March 2009 (UTC)
Here's my consolidated list again (plus one new article), with my reasonings added. Note that I'm not drawing a line in the sand; I'm just elucidating my reasoning. The list of nine articles:
I'm open to further consolidation if there's consensus. However, cutting the 23 articles down to 3 (plus material placed in other articles) is more than I'd like. -- Dan Griscom ( talk) 23:34, 3 March 2009 (UTC)
Well, I guess I'd better get going on this. For my own reference (and in case anyone else wants to dig in), here's my current thinking on the final article list:
I'm least certain of the LED products page. I was thinking to gather together a set of LED-based products that (for the most part) don't really deserve their own articles. I'm no longer sure this is a useful path, though; perhaps these articles should just be improved in-place (or nominated for deletion). Thoughts? -- Dan Griscom ( talk) 03:01, 8 March 2009 (UTC)
"LED Display" I agree that it is under a broad catagory. Seems graphics displays (e.g. signage or generally static billboards) are one technology / product item and video/tv displays are another. I believe the industry is just getting started with video displays (e.g. Samsung's LCD/LED hybrid model)and we have stadium video. I can see separating graphics apps from the video perhaps. What grouping does LED technology history belonge ? - Jim April 25
I suggest that LED TV (LED backlight LCD display) should be merged with LCD TV and not included with the LED articles. With OLED displays included in the LED display section. —Preceding unsigned comment added by 86.172.177.145 ( talk) 07:59, 7 May 2009 (UTC)
—Preceding unsigned comment added by 71.221.240.156 ( talk) 01:21, 26 April 2009 (UTC)
Exploring this thicket of inter-related articles, I am mostly glad so far for the diversity. If they were well-organized and merged, people would start coming along and deciding the resulting mega-articles had "too much unneeded detail" and "simplifying". As things are, many of the articles are stubs, yearning to be fleshed out, which seems better. In conclusion, if you see two smallish articles that seem like a natural match, merging might be fine, but please don't merge something small into something big... - 71.174.180.243 ( talk) 03:05, 16 June 2009 (UTC)
Merge at least some I at least think that the various articles on general illumination with LEDs should get consolidated. This area is changing rapidly and it will make it easier to keep them all up to date. Ccrrccrr ( talk) 04:40, 19 June 2009 (UTC)
Perhaps the design diagrams (low-power and high power leds) from following article can be taken over: http://www.elektor.com/magazines/2008/february/power-to-the-leds.350167.lynkx
Also, the diagram of a common LED should be integrated (consists of die, lens, cooling body and connection wires)
Also, It should be added in the article that red, amber, and orange LEDs are made of AlInGaP (aluminum, indium, gallium, phosphor) green, blue, and cyan LEDs are made of InGaN (indium, gallium, and nitrogen)
The CANbus system should also be mentioned as an open-source solution to power lighting LED's in dwellings. See http://www.elektor.com/magazines/2008/february/the-ledbus-system.350139.lynkx (it allows installation of regular leds instead of led lamps with imbedded electronics)
Thanks,
81.246.131.67 ( talk) 08:11, 6 March 2009 (UTC)
I'm a little disappointed that Torseth removed my image. LEDs are becoming more common in car lighting and a typical way to see a car has LEDs is to see them blink while they drive by, or move your eyes across them. I caught a car with blinking LEDs with a camera and thought, this might be interesting here. It also illustrates nicely, how quickly LEDs can be turned on and off, which is also mentioned in the article. But true, you don't see much of it on the thumbnail.
I wonder, if there are combined back-/brake lights, where the backlight function is with PWM while the brakelight is with full duty cycle. But maybe these lights are required to be separate.
Nevertheless, thanks for your work on this article, Torseth. Darsie from german wiki pedia ( talk) 12:59, 19 March 2009 (UTC)
"While not an LED as such, an ordinary NPN bipolar transistor will emit violet light if its emitter-base junction is subjected to non-destructive reverse breakdown. This is easy to demonstrate by filing the top off a metal-can transistor (BC107, 2N2222 or similar) and biasing it well above emitter-base breakdown (≥ 20 V) via a current-limiting resistor."
Apart from being about NPN technology rather than LED this is unintelligible to me as a non-specialist -- AndyCPrivate ( talk) 13:44, 12 May 2009 (UTC)
Well I would guess that you create some hole/electron pairs in what is effectively a PN junction that recombine at "zero-k" in the band gap, if the material is germanium for instance this is quite natural, for silicon I don't know... -- Thorseth ( talk) 23:40, 13 May 2009 (UTC)
Please add data about the biggest LED makers, how much they make per year, where the LEDs are actually made, and whether the parts are actually made by them, or made by others for them.
What hazards and pollution are associated with manufacture? Where has this had the most impact? - 96.237.10.106 ( talk) 12:48, 3 June 2009 (UTC)
I removed the statement that LEDs would result in 50X less waste compared to incandescents. Heft a high power LED screw-in replacement, with its Al heatsinks, etc. Then feel how light an incandescent bulb. Next consider that glass is a lot less energy intensive to produce than aluminum. That statement was not justified. Ccrrccrr ( talk) 04:36, 19 June 2009 (UTC)
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